Cell-permeable, mitochondrial-targeted, peptide antioxidants.

PubMed

Szeto, Hazel H

2006-04-21

Cellular oxidative injury has been implicated in aging and a wide array of clinical disorders including ischemia-reperfusion injury; neurodegenerative diseases; diabetes; inflammatory diseases such as atherosclerosis, arthritis, and hepatitis; and drug-induced toxicity. However, available antioxidants have not proven to be particularly effective against many of these disorders. A possibility is that some of the antioxidants do not reach the relevant sites of free radical generation, especially if mitochondria are the primary source of reactive oxygen species (ROS). The SS (Szeto-Schiller) peptide antioxidants represent a novel approach with targeted delivery of antioxidants to the inner mitochondrial membrane. The structural motif of these SS peptides centers on alternating aromatic residues and basic amino acids (aromatic-cationic peptides). These SS peptides can scavenge hydrogen peroxide and peroxynitrite and inhibit lipid peroxidation. Their antioxidant action can be attributed to the tyrosine or dimethyltyrosine residue. By reducing mitochondrial ROS, these peptides inhibit mitochondrial permeability transition and cytochrome c release, thus preventing oxidant-induced cell death. Because these peptides concentrate >1000-fold in the inner mitochondrial membrane, they prevent oxidative cell death with EC50 in the nM range. Preclinical studies support their potential use for ischemia-reperfusion injury and neurodegenerative disorders. Although peptides have often been considered to be poor drug candidates, these small peptides have excellent "druggable" properties, making them promising agents for many diseases with unmet needs.

MitoTEMPO Prevents Oxalate Induced Injury in NRK-52E Cells via Inhibiting Mitochondrial Dysfunction and Modulating Oxidative Stress

PubMed Central

Yu, Xiao; Liu, Jihong

2017-01-01

As one of the major risks for urolithiasis, hyperoxaluria can be caused by genetic defect or dietary intake. And high oxalate induced renal epithelial cells injury is related to oxidative stress and mitochondrial dysfunction. Here, we investigated whether MitoTEMPO, a mitochondria-targeted antioxidant, could protect against oxalate mediated injury in NRK-52E cells via inhibiting mitochondrial dysfunction and modulating oxidative stress. MitoSOX Red was used to determine mitochondrial ROS (mtROS) production. Mitochondrial membrane potential (Δψm) and quantification of ATP synthesis were measured to evaluate mitochondrial function. The protein expression of Nox4, Nox2, and p22 was also detected to explore the effect of oxalate and MitoTEMPO on NADPH oxidase. Our results revealed that pretreatment with MitoTEMPO significantly inhibited oxalate induced lactate dehydrogenase (LDH) and malondialdehyde (MDA) release and decreased oxalate induced mtROS generation. Further, MitoTEMPO pretreatment restored disruption of Δψm and decreased ATP synthesis mediated by oxalate. In addition, MitoTEMPO altered the protein expression of Nox4 and p22 and decreased the protein expression of IL-6 and osteopontin (OPN) induced by oxalate. We concluded that MitoTEMPO may be a new candidate to protect against oxalate induced kidney injury as well as urolithiasis. PMID:28116040

The mitochondrially targeted antioxidant MitoQ protects the intestinal barrier by ameliorating mitochondrial DNA damage via the Nrf2/ARE signaling pathway.

PubMed

Hu, Qiongyuan; Ren, Jianan; Li, Guanwei; Wu, Jie; Wu, Xiuwen; Wang, Gefei; Gu, Guosheng; Ren, Huajian; Hong, Zhiwu; Li, Jieshou

2018-03-14

Disruption of the mucosal barrier following intestinal ischemia reperfusion (I/R) is life threatening in clinical practice. Mitochondrial dysfunction and oxidative stress significantly contribute to the early phase of I/R injury and amplify the inflammatory response. MitoQ is a mitochondrially targeted antioxidant that exerts protective effects following I/R injury. In the present study, we aimed to determine whether and how MitoQ protects intestinal epithelial cells (IECs) from I/R injury. In both in vivo and in vitro studies, we found that MitoQ pretreatment downregulated I/R-induced oxidative stress and stabilized the intestinal barrier, as evidenced by MitoQ-treated I/R mice exhibiting attenuated intestinal hyperpermeability, inflammatory response, epithelial apoptosis, and tight junction damage compared to controls. Mechanistically, I/R elevated mitochondrial 8-hydroxyguanine content, reduced mitochondrial DNA (mtDNA) copy number and mRNA transcription levels, and induced mitochondrial disruption in IECs. However, MitoQ pretreatment dramatically inhibited these deleterious effects. mtDNA depletion alone was sufficient to induce apoptosis and mitochondrial dysfunction of IECs. Mitochondrial transcription factor A (TFAM), a key activator of mitochondrial transcription, was significantly reduced during I/R injury, a phenomenon that was prevented by MitoQ treatment. Furthermore, we observed that thee protective properties of MitoQ were affected by upregulation of cellular antioxidant genes, including HO-1, NQO-1, and γ-GCLC. Transfection with Nrf2 siRNA in IECs exposed to hypoxia/reperfusion conditions partially blocked the effects of MitoQ on mtDNA damage and mitochondrial oxidative stress. In conclusion, our data suggest that MitoQ exerts protective effect on I/R-induced intestinal barrier dysfunction.

Bax-mediated mitochondrial outer membrane permeabilization (MOMP), distinct from the mitochondrial permeability transition, is a key mechanism in diclofenac-induced hepatocyte injury: Multiple protective roles of cyclosporin A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siu, W.P.; Pun, Pamela Boon Li; Latchoumycandane, Calivarathan

2008-03-15

Diclofenac, a widely used nonsteroidal anti-inflammatory drug, has been associated with rare but severe cases of clinical hepatotoxicity. Diclofenac causes concentration-dependent cell death in human hepatocytes (after 24-48 h) by mitochondrial permeabilization via poorly defined mechanisms. To explore whether the cyclophilin D (CyD)-dependent mitochondrial permeability transition (mPT) and/or the mitochondrial outer membrane permeabilization (MOMP) was primarily involved in mediating cell death, we exposed immortalized human hepatocytes (HC-04) to apoptogenic concentrations of diclofenac (> 500 {mu}M) in the presence or absence of inhibitors of upstream mediators. The CyD inhibitor, cyclosporin A (CsA, 2 {mu}M) fully inhibited diclofenac-induced cell injury, suggesting thatmore » mPT was involved. However, CyD gene silencing using siRNA left the cells susceptible to diclofenac toxicity, and CsA still protected the CyD-negative cells from lethal injury. Diclofenac induced early (9 h) activation of Bax and Bak and caused mitochondrial translocation of Bax, indicating that MOMP was involved in cell death. Inhibition of Bax protein expression by using siRNA significantly protected HC-04 from diclofenac-induced cell injury. Diclofenac also induced early Bid activation (tBid formation, 6 h), which is an upstream mechanism that initiates Bax activation and mitochondrial translocation. Bid activation was sensitive to the Ca{sup 2+} chelator, BAPTA. In conclusion, we found that Bax/Bak-mediated MOMP is a key mechanism of diclofenac-induced lethal cell injury in human hepatocytes, and that CsA can prevent MOMP through inhibition of Bax activation. These data support our concept that the Ca{sup 2+}-Bid-Bax-MOMP axis is a critical pathway in diclofenac (metabolite)-induced hepatocyte injury.« less

Prevention of Trauma/Hemorrhagic Shock-Induced Mortality, Apoptosis, Inflammation and Mitochondrial Dysfunction

DTIC Science & Technology

2012-12-01

injury, which they wanted to use to establish if kidney injury occurred in our standard rat T/HS model and to determine whether kidney injury could be...prevented by use of IL-6 as a resuscitation adjuvant. In this experiment, we subjected 6 rats each to either our sham protocol or our standard T/HS...time of accumulation in our standard T/HS protocol. Our results demonstrated that shred blood accumulated sIL-6R over time to concentrations (100 ng

Creatine protects against mitochondrial dysfunction associated with HIV-1 Tat-induced neuronal injury.

PubMed

Stevens, Patrick R; Gawryluk, Jeremy W; Hui, Liang; Chen, Xuesong; Geiger, Jonathan D

2014-01-01

HIV-1 infected individuals live longer but experience a prevalence rate of over 50% for HIV-1 associated neurocognitive disorders (HAND) for which no effective treatment is available. Viral and cellular factors secreted by HIV-1 infected cells lead to neuronal injury and HIV-1 Tat continues to be implicated in the pathogenesis of HAND. Here we tested the hypothesis that creatine protected against HIV-1 Tat-induced neuronal injury by preventing mitochondrial bioenergetic crisis and/or redox catastrophe. Creatine blocked HIV-1 Tat(1-72)-induced increases in neuron cell death and synaptic area loss. Creatine protected against HIV-1 Tat-induced decreases in ATP. Creatine and creatine plus HIV-1 Tat increased cellular levels of creatine, and creatine plus HIV-1 Tat further decreased ratios of phosphocreatine to creatine observed with creatine or HIV-1 Tat treatments alone. Additionally, creatine protected against HIV-1 Tat-induced mitochondrial hypopolarization and HIV-1 Tat-induced mitochondrial permeability transition pore opening. Thus, creatine may be a useful adjunctive therapy against HAND.

Antcin H Protects Against Acute Liver Injury Through Disruption of the Interaction of c-Jun-N-Terminal Kinase with Mitochondria

PubMed Central

Huo, Yazhen; Win, Sanda; Than, Tin Aung; Yin, Shutao; Ye, Min

2017-01-01

Abstract Aim: Antrodia Camphorate (AC) is a mushroom that is widely used in Asian countries to prevent and treat various diseases, including liver diseases. However, the active ingredients that contribute to the biological functions remain elusive. The purpose of the present study is to test the hepatoprotective effect of Antcin H, a major triterpenoid chemical isolated from AC, in murine models of acute liver injury. Results: We found that Antcin H pretreatment protected against liver injury in both acetaminophen (APAP) and galactosamine/tumor necrosis factor (TNF)α models. More importantly, Antcin H also offered a significant protection against acetaminophen-induced liver injury when it was given 1 h after acetaminophen. The protection was verified in primary mouse hepatocytes. Antcin H prevented sustained c-Jun-N-terminal kinase (JNK) activation in both models. We excluded an effect of Antcin H on acetaminophen metabolism and TNF receptor signaling and excluded a direct effect as a free radical scavenger or JNK inhibitor. Since the sustained JNK activation through its interaction with mitochondrial Sab, leading to increased mitochondrial reactive oxygen species (ROS), is pivotal in both models, we examined the effect of Antcin H on p-JNK binding to mitochondria and impairment of mitochondrial respiration. Antcin H inhibited the direct effect of p-JNK on isolated mitochondrial function and binding to isolated mitochondria. Innovation and Conclusion: Our study has identified Antcin H as a novel active ingredient that contributes to the hepatoprotective effect of AC, and Antcin H protects against liver injury through disruption of the binding of p-JNK to Sab, which interferes with the ROS-dependent self-sustaining activation of MAPK cascade. Antioxid. Redox Signal. 26, 207–220. PMID:27596680

Mitochondrial mechanisms of neuronal rescue by F-68, a hydrophilic Pluronic block co-polymer, following acute substrate deprivation.

PubMed

Wang, Janice C; Bindokas, Vytautas P; Skinner, Matthew; Emrick, Todd; Marks, Jeremy D

2017-10-01

Global brain ischemia can lead to widespread neuronal death and poor neurologic outcomes in patients. Despite detailed understanding of the cellular and molecular mechanisms mediating neuronal death following focal and global brain hypoxia-ischemia, treatments to reduce ischemia-induced brain injury remain elusive. One pathway central to neuronal death following global brain ischemia is mitochondrial dysfunction, one consequence of which is the cascade of intracellular events leading to mitochondrial outer membrane permeabilization. A novel approach to rescuing injured neurons from death involves targeting cellular membranes using a class of synthetic molecules called Pluronics. Pluronics are triblock copolymers of hydrophilic poly[ethylene oxide] (PEO) and hydrophobic poly[propylene oxide] (PPO). Evidence is accumulating to suggest that hydrophilic Pluronics rescue injured neurons from death following substrate deprivation by preventing mitochondrial dysfunction. Here, we will review current understanding of the nature of interaction of Pluronic molecules with biological membranes and the efficacy of F-68, an 80% hydrophilic Pluronic, in rescuing neurons from injury. We will review data indicating that F-68 reduces mitochondrial dysfunction and mitochondria-dependent death pathways in a model of neuronal injury in vitro, and present new evidence that F-68 acts directly on mitochondria to inhibit mitochondrial outer membrane permeabilization. Finally, we will present results of a pilot, proof-of-principle study suggesting that F-68 is effective in reducing hippocampal injury induced by transient global ischemia in vivo. By targeting mitochondrial dysfunction, F-68 and other Pluronic molecules constitute an exciting new approach to rescuing neurons from acute injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gallic acid prevents nonsteroidal anti-inflammatory drug-induced gastropathy in rat by blocking oxidative stress and apoptosis.

PubMed

Pal, Chinmay; Bindu, Samik; Dey, Sumanta; Alam, Athar; Goyal, Manish; Iqbal, Mohd Shameel; Maity, Pallab; Adhikari, Susanta S; Bandyopadhyay, Uday

2010-07-15

Nonsteroidal anti-inflammatory drug (NSAID)-induced oxidative stress plays a critical role in gastric mucosal cell apoptosis and gastropathy. NSAIDs induce the generation of hydroxyl radical ((*)OH) through the release of free iron, which plays an important role in developing gastropathy. Thus, molecules having both iron-chelating and antiapoptotic properties will be beneficial in preventing NSAID-induced gastropathy. Gallic acid (GA), a polyphenolic natural product, has the capacity to chelate free iron. Here, we report that GA significantly prevents, as well as heals, NSAID-induced gastropathy. In vivo, GA blocks NSAID-mediated mitochondrial oxidative stress by preventing mitochondrial protein carbonyl formation, lipid peroxidation, and thiol depletion. In vitro, GA scavenges free radicals and blocks (*)OH-mediated oxidative damage. GA also attenuates gastric mucosal cell apoptosis in vivo as well as in vitro in cultured gastric mucosal cells as evident from the TUNEL assay. GA prevents NSAID-induced activation of caspase-9, a marker for the mitochondrial pathway of apoptosis, and restores NSAID-mediated collapse of the mitochondrial transmembrane potential and dehydrogenase activity. Thus, the inhibition of mitochondrial oxidative stress by GA is associated with the inhibition of NSAID-induced mitochondrial dysfunction and activation of apoptosis in gastric mucosal cells, which are responsible for gastric injury or gastropathy. Copyright 2010 Elsevier Inc. All rights reserved.

Krüppel-like factor 6 regulates mitochondrial function in the kidney

PubMed Central

Mallipattu, Sandeep K.; Horne, Sylvia J.; D’Agati, Vivette; Narla, Goutham; Liu, Ruijie; Frohman, Michael A.; Dickman, Kathleen; Chen, Edward Y.; Ma’ayan, Avi; Bialkowska, Agnieszka B.; Ghaleb, Amr M.; Nandan, Mandayam O.; Jain, Mukesh K.; Daehn, Ilse; Chuang, Peter Y.; Yang, Vincent W.; He, John C.

2015-01-01

Maintenance of mitochondrial structure and function is critical for preventing podocyte apoptosis and eventual glomerulosclerosis in the kidney; however, the transcription factors that regulate mitochondrial function in podocyte injury remain to be identified. Here, we identified Krüppel-like factor 6 (KLF6), a zinc finger domain transcription factor, as an essential regulator of mitochondrial function in podocyte apoptosis. We observed that podocyte-specific deletion of Klf6 increased the susceptibility of a resistant mouse strain to adriamycin-induced (ADR-induced) focal segmental glomerulosclerosis (FSGS). KLF6 expression was induced early in response to ADR in mice and cultured human podocytes, and prevented mitochondrial dysfunction and activation of intrinsic apoptotic pathways in these podocytes. Promoter analysis and chromatin immunoprecipitation studies revealed that putative KLF6 transcriptional binding sites are present in the promoter of the mitochondrial cytochrome c oxidase assembly gene (SCO2), which is critical for preventing cytochrome c release and activation of the intrinsic apoptotic pathway. Additionally, KLF6 expression was reduced in podocytes from HIV-1 transgenic mice as well as in renal biopsies from patients with HIV-associated nephropathy (HIVAN) and FSGS. Together, these findings indicate that KLF6-dependent regulation of the cytochrome c oxidase assembly gene is critical for maintaining mitochondrial function and preventing podocyte apoptosis. PMID:25689250

Curcumin prevents cisplatin-induced renal alterations in mitochondrial bioenergetics and dynamic.

PubMed

Ortega-Domínguez, Bibiana; Aparicio-Trejo, Omar Emiliano; García-Arroyo, Fernando E; León-Contreras, Juan Carlos; Tapia, Edilia; Molina-Jijón, Eduardo; Hernández-Pando, Rogelio; Sánchez-Lozada, Laura Gabriela; Barrera-Oviedo, Diana; Pedraza-Chaverri, José

2017-09-01

Cisplatin is widely used as chemotherapeutic agent for treatment of diverse types of cancer, however, acute kidney injury (AKI) is an important side effect of this treatment. Diverse mechanisms have been involved in cisplatin-induced AKI, such as oxidative stress, apoptosis and mitochondrial damage. On the other hand, curcumin is a polyphenol extracted from the rhizome of Curcuma longa L. Previous studies have shown that curcumin protects against the cisplatin-induced AKI; however, it is unknown whether curcumin can reduce alterations in mitochondrial bioenergetics and dynamic in this model. It was found that curcumin prevents cisplatin-induced: (a) AKI and (b) alterations in the following mitochondrial parameters: bioenergetics, ultrastructure, hydrogen peroxide production and dynamic. In fact, curcumin prevented the increase of mitochondrial fission 1 protein (FIS1), the decrease of optic atrophy 1 protein (OPA1) and the decrease of NAD + -dependent deacetylase sirtuin-3 (SIRT3), a mitochondrial dynamic regulator as well as the increase in the mitophagy associated proteins parkin and phosphatase and tensin homologue (PTEN)-induced putative kinase protein 1 (PINK1). In conclusion, the protective effect of curcumin in cisplatin-induced AKI was associated with the prevention of the alterations in mitochondrial bioenergetics, ultrastructure, redox balance, dynamic, and SIRT3 levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogen Sulfide Preconditioning Protects Rat Liver against Ischemia/Reperfusion Injury by Activating Akt-GSK-3β Signaling and Inhibiting Mitochondrial Permeability Transition

PubMed Central

Zhang, Hao; Xu, Fengying; Zou, Zui; Liu, Meng; Wang, Quanxing; Miao, Mingyong; Shi, Xueyin

2013-01-01

Hydrogen sulfide (H2S) is the third most common endogenously produced gaseous signaling molecule, but its impact on hepatic ischemia/reperfusion (I/R) injury, especially on mitochondrial function, remains unclear. In this study, rats were randomized into Sham, I/R, ischemia preconditioning (IPC) or sodium hydrosulfide (NaHS, an H2S donor) preconditioning groups. To establish a model of segmental (70%) warm hepatic ischemia, the hepatic artery, left portal vein and median liver lobes were occluded for 60 min and then unclamped to allow reperfusion. Preconditioning with 12.5, 25 or 50 μmol/kg NaHS prior to the I/R insult significantly increased serum H2S levels, and, similar to IPC, NaHS preconditioning decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the plasma and prevented hepatocytes from undergoing I/R-induced necrosis. Moreover, a sub-toxic dose of NaHS (25 μmol/kg) did not disrupt the systemic hemodynamics but dramatically inhibited mitochondrial permeability transition pore (MPTP) opening and thus prevented mitochondrial-related cell death and apoptosis. Mechanistic studies revealed that NaHS preconditioning markedly increased the expression of phosphorylated protein kinase B (p-Akt), phosphorylated glycogen synthase kinase-3 beta (p-GSK-3β) and B-cell lymphoma-2 (Bcl-2) and decreased the release of mitochondrial cytochrome c and cleaved caspase-3/9 levels. Therefore, NaHS administration prior to hepatic I/R ameliorates mitochondrial and hepatocellular damage through the inhibition of MPTP opening and the activation of Akt-GSK-3β signaling. Furthermore, this study provides experimental evidence for the clinical use of H2S to reduce liver damage after perioperative I/R injury. PMID:24058562

Mitochondriotropic and Cardioprotective Effects of Triphenylphosphonium-Conjugated Derivatives of the Diterpenoid Isosteviol

PubMed Central

Strobykina, Irina; Semenov, Victor V.; Semenova, Marina; Martelli, Alma; Citi, Valentina; Breschi, Maria C.; Kataev, Vladimir E.; Calderone, Vincenzo

2017-01-01

Mitochondria play a crucial role in the cell fate; in particular, reducing the accumulation of calcium in the mitochondrial matrix offers cardioprotection. This affect is achieved by a mild depolarization of the mitochondrial membrane potential, which prevents the assembly and opening of the mitochondrial permeability transition pore. For this reason, mitochondria are an attractive target for pharmacological interventions that prevent ischaemia/reperfusion injury. Isosteviol is a diterpenoid created from the acid hydrolysis of Stevia rebaudiana Bertoni (fam. Asteraceae) glycosides that has shown protective effects against ischaemia/reperfusion injury, which are likely mediated through the activation of mitochondrial adenosine tri-phosphate (ATP)-sensitive potassium (mitoKATP) channels. Some triphenylphosphonium (triPP)-conjugated derivatives of isosteviol have been developed, and to evaluate the possible pharmacological benefits that result from these synthetic modifications, in this study, the mitochondriotropic properties of isosteviol and several triPP-conjugates were investigated in rat cardiac mitochondria and in the rat heart cell line H9c2. This study’s main findings highlight the ability of isosteviol to depolarize the mitochondrial membrane potential and reduce calcium uptake by the mitochondria, which are typical functions of mitochondrial potassium channel openings. Moreover, triPP-conjugated derivatives showed a similar behavior to isosteviol but at lower concentrations, indicative of their improved uptake into the mitochondrial matrix. Finally, the cardioprotective property of a selected triPP-conjugated derivative was demonstrated in an in vivo model of acute myocardial infarct. PMID:28954424

Mitochondria-targeted antioxidant mitotempo protects mitochondrial function against amyloid beta toxicity in primary cultured mouse neurons.

PubMed

Hu, Hongtao; Li, Mo

2016-09-09

Mitochondrial defects including excess reactive oxygen species (ROS) production and compromised ATP generation are featured pathology in Alzheimer's disease (AD). Amyloid beta (Aβ)-mediated mitochondrial ROS overproduction disrupts intra-neuronal Redox balance, in turn exacerbating mitochondrial dysfunction leading to neuronal injury. Previous studies have found the beneficial effects of mitochondria-targeted antioxidants in preventing mitochondrial dysfunction and neuronal injury in AD animal and cell models, suggesting that mitochondrial ROS scavengers hold promise for the treatment of this neurological disorder. In this study, we have determined that mitotempo, a novel mitochondria-targeted antioxidant protects mitochondrial function from the toxicity of Aβ in primary cultured neurons. Our results showed that Aβ-promoted mitochondrial superoxide production and neuronal lipid oxidation were significantly suppressed by the application of mitotempo. Moreover, mitotempo also demonstrated protective effects on mitochondrial bioenergetics evidenced by preserved mitochondrial membrane potential, cytochrome c oxidase activity as well as ATP production. In addition, the Aβ-induced mitochondrial DNA (mtDNA) depletion and decreased expression levels of mtDNA replication-related DNA polymerase gamma (DNA pol γ) and Twinkle were substantially mitigated by mitotempo. Therefore, our study suggests that elimination of excess mitochondrial ROS rescues mitochondrial function in Aβ-insulted neruons; and mitotempo has the potential to be a promising therapeutic agent to protect mitochondrial and neuronal function in AD. Copyright © 2016 Elsevier Inc. All rights reserved.

Exercise Prevents Cardiac Injury and Improves Mitochondrial Biogenesis in Advanced Diabetic Cardiomyopathy with PGC-1α and Akt Activation.

PubMed

Wang, Hui; Bei, Yihua; Lu, Yan; Sun, Wei; Liu, Qi; Wang, Yalong; Cao, Yujie; Chen, Ping; Xiao, Junjie; Kong, Xiangqing

2015-01-01

Diabetic cardiomyopathy (DCM) represents the major cause of morbidity and mortality among diabetics. Exercise has been reported to be effective to protect the heart from cardiac injury during the development of DCM. However, the potential cardioprotective effect of exercise in advanced DCM remains unclear. Seven-week old male C57BL/6 wild-type or db/db mice were either subjected to a running exercise program for 15 weeks or kept sedentary. Cardiac function, myocardial apoptosis and fibrosis, and mitochondrial biogenesis were examined for evaluation of cardiac injury. A reduction in ejection fraction and fractional shortening in db/db mice was significantly reversed by exercise training. DCM induced remarkable cardiomyocyte apoptosis and increased ratio of Bax/Bcl-2 at the protein level. Meanwhile, DCM caused slightly myocardial fibrosis with elevated mRNA levels of collagen I and collagen III. Also, DCM resulted in a reduction of mitochondrial DNA (mtDNA) replication and transcription, together with reduced mtDNA content and impaired mitochondrial ultrastructure. All of these changes could be abolished by exercise training. Furthermore, DCM-associated inhibition of PGC-1α and Akt signaling was significantly activated by exercise, indicating that exercise-induced activation of PGC-1α and Akt signaling might be responsible for mediating cardioprotective effect of exercise in DCM. Exercise preserves cardiac function, prevents myocardial apoptosis and fibrosis, and improves mitochondrial biogenesis in the late stage of DCM. Exercise-induced activation of PGC-1α and Akt signaling might be promising therapeutic targets for advanced DCM. © 2015 S. Karger AG, Basel.

Creatine protects against mitochondrial dysfunction associated with HIV-1 Tat-induced neuronal injury

PubMed Central

Stevens, Patrick R.; Gawryluk, Jeremy W.; Hui, Liang; Chen, Xuesong; Geiger, Jonathan D.

2015-01-01

HIV-1 infected individuals are living longer but experiencing a prevalence rate of over 50% for HIV-1 associated neurocognitive disorders (HAND) for which no effective treatment is available. Viral and cellular factors secreted by HIV-1 infected cells leads to neuronal injury and HIV-1 Tat continues to be implicated in the pathogenesis of HAND. Here we tested the hypothesis that creatine protected against HIV-1 Tat-induced neuronal injury by preventing mitochondrial bioenergetic crisis and/or redox catastrophe. Creatine blocked HIV-1 Tat1-72-induced increases in neuron cell death and synaptic area loss. Creatine protected against HIV-1 Tat-induced decreases in ATP. Creatine and creatine plus HIV-1 Tat increased cellular levels of creatine, and creatine plus HIV-1 Tat further decreased ratios of phosphocreatine to creatine observed with creatine or HIV-1 Tat treatments alone. Additionally, creatine protected against HIV-1 Tat-induced mitochondrial hypopolarization and HIV-1 Tat-induced mitochondrial permeability transition pore opening. Thus, creatine may be a useful adjunctive therapy against HAND. PMID:25613139

Parkinson's disease proteins: Novel mitochondrial targets for cardioprotection

PubMed Central

Mukherjee, Uma A.; Ong, Sang-Bing; Ong, Sang-Ging; Hausenloy, Derek J.

2015-01-01

Ischemic heart disease (IHD) is the leading cause of death and disability worldwide. Therefore, novel therapeutic targets for protecting the heart against acute ischemia/reperfusion injury (IRI) are required to attenuate cardiomyocyte death, preserve myocardial function, and prevent the onset of heart failure. In this regard, a specific group of mitochondrial proteins, which have been linked to familial forms of Parkinson's disease (PD), may provide novel therapeutic targets for cardioprotection. In dopaminergic neurons of the substantia nigra, these PD proteins, which include Parkin, PINK1, DJ-1, LRRK2, and α-synuclein, play essential roles in preventing cell death—through maintaining normal mitochondrial function, protecting against oxidative stress, mediating mitophagy, and preventing apoptosis. These rare familial forms of PD may therefore provide important insights into the pathophysiology underlying mitochondrial dysfunction and the development of PD. Interestingly, these PD proteins are also present in the heart, but their role in myocardial health and disease is not clear. In this article, we review the role of these PD proteins in the heart and explore their potential as novel mitochondrial targets for cardioprotection. PMID:26481155

Preventive effects of indole-3-carbinol against alcohol-induced liver injury in mice via antioxidant, anti-inflammatory, and anti-apoptotic mechanisms: Role of gut-liver-adipose tissue axis.

PubMed

Choi, Youngshim; Abdelmegeed, Mohamed A; Song, Byoung-Joon

2018-05-01

Indole-3-carbinol (I3C), found in Brassica family vegetables, exhibits antioxidant, anti-inflammatory, and anti-cancerous properties. Here, we aimed to evaluate the preventive effects of I3C against ethanol (EtOH)-induced liver injury and study the protective mechanism(s) by using the well-established chronic-plus-binge alcohol exposure model. The preventive effects of I3C were evaluated by conducting various histological, biochemical, and real-time PCR analyses in mouse liver, adipose tissue, and colon, since functional alterations of adipose tissue and intestine can also participate in promoting EtOH-induced liver damage. Daily treatment with I3C alleviated EtOH-induced liver injury and hepatocyte apoptosis, but not steatosis, by attenuating elevated oxidative stress, as evidenced by the decreased levels of hepatic lipid peroxidation, hydrogen peroxide, CYP2E1, NADPH-oxidase, and protein acetylation with maintenance of mitochondrial complex I, II, and III protein levels and activities. I3C also restored the hepatic antioxidant capacity by preventing EtOH-induced suppression of glutathione contents and mitochondrial aldehyde dehydrogenase-2 activity. I3C preventive effects were also achieved by attenuating the increased levels of hepatic proinflammatory cytokines, including IL1β, and neutrophil infiltration. I3C also attenuated EtOH-induced gut leakiness with decreased serum endotoxin levels through preventing EtOH-induced oxidative stress, apoptosis of enterocytes, and alteration of tight junction protein claudin-1. Furthermore, I3C alleviated adipose tissue inflammation and decreased free fatty acid release. Collectively, I3C prevented EtOH-induced liver injury via attenuating the damaging effect of ethanol on the gut-liver-adipose tissue axis. Therefore, I3C may also have a high potential for translational research in treating or preventing other types of hepatic injury associated with oxidative stress and inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

Mitochondria selective S-nitrosation by mitochondria-targeted S-nitrosothiol protects against post-infarct heart failure in mouse hearts.

PubMed

Methner, Carmen; Chouchani, Edward T; Buonincontri, Guido; Pell, Victoria R; Sawiak, Stephen J; Murphy, Michael P; Krieg, Thomas

2014-07-01

Recently it has been shown that the mitochondria-targeted S-nitrosothiol MitoSNO protects against acute ischaemia/reperfusion (IR) injury by inhibiting the reactivation of mitochondrial complex I in the first minutes of reperfusion of ischaemic tissue, thereby preventing free radical formation that underlies IR injury. However, it remains unclear how this transient inhibition of mitochondrial complex I-mediated free radicals at reperfusion affects the long-term recovery of the heart following IR injury. Here we determined whether the acute protection by MitoSNO at reperfusion prevented the subsequent development of post-myocardial infarction heart failure. Mice were subjected to 30 min left coronary artery occlusion followed by reperfusion and recovery over 28 days. MitoSNO (100 ng/kg) was applied 5 min before the onset of reperfusion followed by 20 min infusion (1 ng/kg/min). Infarct size and cardiac function were measured by magnetic resonance imaging (MRI) 24 h after infarction. MitoSNO-treated mice exhibited reduced infarct size and preserved function. In addition, MitoSNO at reperfusion improved outcome measures 28 days post-IR, including preserved systolic function (63.7 ±1.8% LVEF vs. 53.7 ± 2.1% in controls, P = 0.01) and tissue fibrosis. MitoSNO action acutely at reperfusion reduces infarct size and protects from post-myocardial infarction heart failure. Therefore, targeted inhibition of mitochondrial complex I in the first minutes of reperfusion by MitoSNO is a rational therapeutic strategy for preventing subsequent heart failure in patients undergoing IR injury. © 2014 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.

Glomerular Endothelial Mitochondrial Dysfunction Is Essential and Characteristic of Diabetic Kidney Disease Susceptibility.

PubMed

Qi, Haiying; Casalena, Gabriella; Shi, Shaolin; Yu, Liping; Ebefors, Kerstin; Sun, Yezhou; Zhang, Weijia; D'Agati, Vivette; Schlondorff, Detlef; Haraldsson, Börje; Böttinger, Erwin; Daehn, Ilse

2017-03-01

The molecular signaling mechanisms between glomerular cell types during initiation/progression of diabetic kidney disease (DKD) remain poorly understood. We compared the early transcriptome profile between DKD-resistant C57BL/6J and DKD-susceptible DBA/2J (D2) glomeruli and demonstrated a significant downregulation of essential mitochondrial genes in glomeruli from diabetic D2 mice, but not in C57BL/6J, with comparable hyperglycemia. Diabetic D2 mice manifested increased mitochondrial DNA lesions (8-oxoguanine) exclusively localized to glomerular endothelial cells after 3 weeks of diabetes, and these accumulated over time in addition to increased urine secretion of 8-oxo-deoxyguanosine. Detailed assessment of glomerular capillaries from diabetic D2 mice demonstrated early signs of endothelial injury and loss of fenestrae. Glomerular endothelial mitochondrial dysfunction was associated with increased glomerular endothelin-1 receptor type A (Ednra) expression and increased circulating endothelin-1 (Edn1). Selective Ednra blockade or mitochondrial-targeted reactive oxygen species scavenging prevented mitochondrial oxidative stress of endothelial cells and ameliorated diabetes-induced endothelial injury, podocyte loss, albuminuria, and glomerulosclerosis. In human DKD, increased urine 8-oxo-deoxyguanosine was associated with rapid DKD progression, and biopsies from patients with DKD showed increased mitochondrial DNA damage associated with glomerular endothelial EDNRA expression. Our studies show that DKD susceptibility was linked to mitochondrial dysfunction, mediated largely by Edn1-Ednra in glomerular endothelial cells representing an early event in DKD progression, and suggest that cross talk between glomerular endothelial injury and podocytes leads to defects and depletion, albuminuria, and glomerulosclerosis. © 2017 by the American Diabetes Association.

Targeting cholesterol at different levels in the mevalonate pathway protects fatty liver against ischemia-reperfusion injury.

PubMed

Llacuna, Laura; Fernández, Anna; Montfort, Claudia Von; Matías, Núria; Martínez, Laura; Caballero, Francisco; Rimola, Antoni; Elena, Montserrat; Morales, Albert; Fernández-Checa, José C; García-Ruiz, Carmen

2011-05-01

Liver steatosis enhances ischemia/reperfusion (I/R) injury and is considered a primary factor in graft failure after liver transplantation. Although previous reports have shown a role for qualitative steatosis (macrovesicular vs. microvesicular) in hepatic I/R injury, no studies have compared side by side the specific contribution of individual lipids accumulating in fatty liver to I/R damage. We used nutritional and genetic models of micro and macrovesicular fatty livers exhibiting specific lipid profiles to assess their susceptibility to normothermic I/R injury. Unlike choline-deficient (CD) diet-fed mice, characterized by predominant liver triglycerides/free fatty acids (TG/FFA) accumulation, mice fed a cholesterol-enriched (HC) diet, which exhibited enhanced hepatic cholesterol loading in mitochondria, were highly sensitive to I/R-induced liver injury. In vivo two-photon confocal imaging revealed enhanced mitochondrial depolarization and generation of reactive oxygen species following hepatic I/R in HC-fed but not in CD-fed mice, consistent with decreased mitochondrial GSH (mGSH) observed in HC-fed mice. Moreover, ob/ob mice, characterized by increased hepatic TG, FFA, and cholesterol levels, were as sensitive to I/R-mediated liver injury as mice fed the HC diet. Livers from ob/ob mice displayed increased StAR expression and mitochondrial cholesterol accumulation, resulting in mGSH depletion. Interestingly, atorvastatin therapy or squalene synthase inhibition in vivo attenuated StAR overexpression, mitochondrial cholesterol loading, and mGSH depletion, protecting ob/ob mice from I/R-mediated liver injury. Cholesterol accumulation, particularly in mitochondria, sensitizes to hepatic I/R injury, and thus represents a novel target to prevent the enhanced damage of steatotic livers to I/R-mediated damage. Copyright © 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Reduction of Mitochondria-Endoplasmic Reticulum Interactions by Acetylcholine Protects Human Umbilical Vein Endothelial Cells From Hypoxia/Reoxygenation Injury.

PubMed

He, Xi; Bi, Xue-Yuan; Lu, Xing-Zhu; Zhao, Ming; Yu, Xiao-Jiang; Sun, Lei; Xu, Man; Wier, W Gil; Zang, Wei-Jin

2015-07-01

We explored the role of endoplasmic reticulum (ER)-mitochondria Ca(2+) cross talk involving voltage-dependent anion channel-1 (VDAC1)/glucose-regulated protein 75/inositol 1,4,5-trisphosphate receptor 1 complex and mitofusin 2 in endothelial cells during hypoxia/reoxygenation (H/R), and investigated the protective effects of acetylcholine. Acetylcholine treatment during reoxygenation prevented intracellular and mitochondrial Ca(2+) increases and alleviated ER Ca(2+) depletion during H/R in human umbilical vein endothelial cells. Consequently, acetylcholine enhanced mitochondrial membrane potential and inhibited proapoptotic cascades, thereby reducing cell death and preserving endothelial ultrastructure. This effect was likely mediated by the type-3 muscarinic acetylcholine receptor and the phosphatidylinositol 3-kinase/Akt pathway. In addition, interactions among members of the VDAC1/glucose-regulated protein 75/inositol 1,4,5-trisphosphate receptor 1 complex were increased after H/R and were associated with mitochondrial Ca(2+) overload and cell death. Inhibition of the partner of the Ca(2+) channeling complex (VDAC1 siRNA) or a reduction in ER-mitochondria tethering (mitofusin 2 siRNA) prevented the increased protein interaction within the complex and reduced mitochondrial Ca(2+) accumulation and subsequent endothelial cell death after H/R. Intriguingly, acetylcholine could modulate ER-mitochondria Ca(2+) cross talk by inhibiting the VDAC1/glucose-regulated protein 75/inositol 1,4,5-trisphosphate receptor 1 complex and mitofusin 2 expression. Phosphatidylinositol 3-kinase siRNA diminished acetylcholine-mediated inhibition of mitochondrial Ca(2+) overload and VDAC1/glucose-regulated protein 75/inositol 1,4,5-trisphosphate receptor 1 complex formation induced by H/R. Our data suggest that ER-mitochondria interplay plays an important role in reperfusion injury in the endothelium and may be a novel molecular target for endothelial protection. Acetylcholine attenuates both intracellular and mitochondrial Ca(2+) overload and protects endothelial cells from H/R injury, presumably by disrupting the ER-mitochondria interaction. © 2015 American Heart Association, Inc.

Targeting an antioxidant to mitochondria decreases cardiac ischemia-reperfusion injury.

PubMed

Adlam, Victoria J; Harrison, Joanne C; Porteous, Carolyn M; James, Andrew M; Smith, Robin A J; Murphy, Michael P; Sammut, Ivan A

2005-07-01

Mitochondrial oxidative damage contributes to a wide range of pathologies, including cardiovascular disorders and neurodegenerative diseases. Therefore, protecting mitochondria from oxidative damage should be an effective therapeutic strategy. However, conventional antioxidants have limited efficacy due to the difficulty of delivering them to mitochondria in situ. To overcome this problem, we developed mitochondria-targeted antioxidants, typified by MitoQ, which comprises a lipophilic triphenylphosphonium (TPP) cation covalently attached to a ubiquinol antioxidant. Driven by the large mitochondrial membrane potential, the TPP cation concentrates MitoQ several hundred-fold within mitochondria, selectively preventing mitochondrial oxidative damage. To test whether MitoQ was active in vivo, we chose a clinically relevant form of mitochondrial oxidative damage: cardiac ischemia-reperfusion injury. Feeding MitoQ to rats significantly decreased heart dysfunction, cell death, and mitochondrial damage after ischemia-reperfusion. This protection was due to the antioxidant activity of MitoQ within mitochondria, as an untargeted antioxidant was ineffective and accumulation of the TPP cation alone gave no protection. Therefore, targeting antioxidants to mitochondria in vivo is a promising new therapeutic strategy in the wide range of human diseases such as Parkinson's disease, diabetes, and Friedreich's ataxia where mitochondrial oxidative damage underlies the pathology.

Polyethylene glycol rinse solution: An effective way to prevent ischemia-reperfusion injury

PubMed Central

Zaouali, Mohamed Amine; Bejaoui, Mohamed; Calvo, Maria; Folch-Puy, Emma; Pantazi, Eirini; Pasut, Gianfranco; Rimola, Antoni; Ben Abdennebi, Hassen; Adam, René; Roselló-Catafau, Joan

2014-01-01

AIM: To test whether a new rinse solution containing polyethylene glycol 35 (PEG-35) could prevent ischemia-reperfusion injury (IRI) in liver grafts. METHODS: Sprague-Dawley rat livers were stored in University of Wisconsin preservation solution and then washed with different rinse solutions (Ringer’s lactate solution and a new rinse solution enriched with PEG-35 at either 1 or 5 g/L) before ex vivo perfusion with Krebs-Heinseleit buffer solution. We assessed the following: liver injury (transaminase levels), mitochondrial damage (glutamate dehydrogenase activity), liver function (bile output and vascular resistance), oxidative stress (malondialdehyde), nitric oxide, liver autophagy (Beclin-1 and LCB3) and cytoskeleton integrity (filament and globular actin fraction); as well as levels of metalloproteinases (MMP2 and MMP9), adenosine monophosphate-activated protein kinase (AMPK), heat shock protein 70 (HSP70) and heme oxygenase 1 (HO-1). RESULTS: When we used the PEG-35 rinse solution, reduced hepatic injury and improved liver function were noted after reperfusion. The PEG-35 rinse solution prevented oxidative stress, mitochondrial damage, and liver autophagy. Further, it increased the expression of cytoprotective heat shock proteins such as HO-1 and HSP70, activated AMPK, and contributed to the restoration of cytoskeleton integrity after IRI. CONCLUSION: Using the rinse solution containing PEG-35 was effective for decreasing liver graft vulnerability to IRI. PMID:25473175

Baicalein Reduces Airway Injury in Allergen and IL-13 Induced Airway Inflammation

PubMed Central

Mabalirajan, Ulaganathan; Ahmad, Tanveer; Rehman, Rakhshinda; Leishangthem, Geeta Devi; Dinda, Amit Kumar; Agrawal, Anurag; Ghosh, Balaram; Sharma, Surendra Kumar

2013-01-01

Background Baicalein, a bioflavone present in the dry roots of Scutellaria baicalensis Georgi, is known to reduce eotaxin production in human fibroblasts. However, there are no reports of its anti-asthma activity or its effect on airway injury. Methodology/Principal Findings In a standard experimental asthma model, male Balb/c mice that were sensitized with ovalbumin (OVA), treated with baicalein (10 mg/kg, ip) or a vehicle control, either during (preventive use) or after OVA challenge (therapeutic use). In an alternate model, baicalein was administered to male Balb/c mice which were given either IL-4 or IL-13 intranasally. Features of asthma were determined by estimating airway hyperresponsiveness (AHR), histopathological changes and biochemical assays of key inflammatory molecules. Airway injury was determined with apoptotic assays, transmission electron microscopy and assessing key mitochondrial functions. Baicalein treatment reduced AHR and inflammation in both experimental models. TGF-β1, sub-epithelial fibrosis and goblet cell metaplasia, were also reduced. Furthermore, baicalein treatment significantly reduced 12/15-LOX activity, features of mitochondrial dysfunctions, and apoptosis of bronchial epithelia. Conclusion/Significance Our findings demonstrate that baicalein can attenuate important features of asthma, possibly through the reduction of airway injury and restoration of mitochondrial function. PMID:23646158

Herba Cistanches stimulates cellular glutathione redox cycling by reactive oxygen species generated from mitochondrial respiration in H9c2 cardiomyocytes.

PubMed

Wong, Hoi Shan; Ko, Kam Ming

2013-01-01

Earlier findings demonstrated that pretreatment of Herba Cistanches [the dried whole plant of Cistanche deserticola Y.C. Ma (Orobanchaceae)], a "Yang-invigorating" Chinese tonic herb, stimulated the ATP-generation capacity (ATP-GC) in mitochondria isolated from rat heart ex vivo. The enhancement of mitochondrial ATP-GC by Herba Cistanches was associated with induction of glutathione antioxidant status and protection against ischemia/reperfusion (I/R) injury in rat hearts. This study investigated the relationship between enhancements in mitochondrial ATP-GC and glutathione antioxidant status in H9c2 cardiomyocytes using a semipurified fraction of Herba Cistanches (HCF1). HCF1 (10-300 ng/mL) was tested for its effects on mitochondrial ATP generation, glutathione antioxidant status and protection against oxidant injury in H9c2 cardiomyocytes and rat hearts. HCF1 at 30 ng/mL increased mitochondrial ATP-GC and ADP-stimulated state 3 respiration (by 50 and 100%, respectively) in H9c2 cardiomyocytes. The stimulation of mitochondrial respiration was associated with the induction of mitochondrial uncoupling (27%) and enhancement of cellular glutathione redox cycling as well as protection against hypoxia/reoxygenation (hypox/reoxy)-induced apoptosis (by 60%). While HCF1 treatment increased reactive oxygen species generation from mitochondrial respiration in H9c2 cardiomyocytes, pretreatment with antioxidants (DMTU) abrogated the HCF1-induced cellular responses and the associated cytoprotective effect. HCF1 pretreatment (1.14 and 3.41 mg/kg × 14) also protected against myocardial I/R injury in rats (by 13 and 32%), presumably mediated by the induction of glutathione antioxidant response. The long-term intake of HCF1 may offer a prospect for the prevention of ischemic heart disease.

Mitochondria-targeted therapies for acute kidney injury.

PubMed

Tábara, Luis Carlos; Poveda, Jonay; Martin-Cleary, Catalina; Selgas, Rafael; Ortiz, Alberto; Sanchez-Niño, Maria D

2014-08-08

Acute kidney injury (AKI) is a serious clinical condition with no effective treatment. Tubular cells are key targets in AKI. Tubular cells and, specifically, proximal tubular cells are extremely rich in mitochondria and mitochondrial changes had long been known to be a feature of AKI. However, only recent advances in understanding the molecules involved in mitochondria biogenesis and dynamics and the availability of mitochondria-targeted drugs has allowed the exploration of the specific role of mitochondria in AKI. We now review the morphological and functional mitochondrial changes during AKI, as well as changes in the expression of mitochondrial genes and proteins. Finally, we summarise the current status of novel therapeutic strategies specifically targeting mitochondria such as mitochondrial permeability transition pore (MPTP) opening inhibitors (cyclosporine A (CsA)), quinone analogues (MitoQ, SkQ1 and SkQR1), superoxide dismutase (SOD) mimetics (Mito-CP), Szeto-Schiller (SS) peptides (Bendavia) and mitochondrial division inhibitors (mdivi-1). MitoQ, SkQ1, SkQR1, Mito-CP, Bendavia and mdivi-1 have improved the course of diverse experimental models of AKI. Evidence for a beneficial effect of CsA on human cardiac ischaemia-reperfusion injury derives from a clinical trial; however, CsA is nephrotoxic. MitoQ and Bendavia have been shown to be safe for humans. Ongoing clinical trials are testing the efficacy of Bendavia in AKI prevention following renal artery percutaneous transluminal angioplasty.

The Mitochondria-Targeted Antioxidant Mitoquinone Protects against Cold Storage Injury of Renal Tubular Cells and Rat Kidneys

PubMed Central

Mitchell, Tanecia; Rotaru, Dumitru; Saba, Hamida; Smith, Robin A. J.; Murphy, Michael P.

2011-01-01

The majority of kidneys used for transplantation are obtained from deceased donors. These kidneys must undergo cold preservation/storage before transplantation to preserve tissue quality and allow time for recipient selection and transport. However, cold storage (CS) can result in tissue injury, kidney discardment, or long-term renal dysfunction after transplantation. We have previously determined mitochondrial superoxide and other downstream oxidants to be important signaling molecules that contribute to CS plus rewarming (RW) injury of rat renal proximal tubular cells. Thus, this study's purpose was to determine whether adding mitoquinone (MitoQ), a mitochondria-targeted antioxidant, to University of Wisconsin (UW) preservation solution could offer protection against CS injury. CS was initiated by placing renal cells or isolated rat kidneys in UW solution alone (4 h at 4°C) or UW solution containing MitoQ or its control compound, decyltriphenylphosphonium bromide (DecylTPP) (1 μM in vitro; 100 μM ex vivo). Oxidant production, mitochondrial function, cell viability, and alterations in renal morphology were assessed after CS exposure. CS induced a 2- to 3-fold increase in mitochondrial superoxide generation and tyrosine nitration, partial inactivation of mitochondrial complexes, and a significant increase in cell death and/or renal damage. MitoQ treatment decreased oxidant production ∼2-fold, completely prevented mitochondrial dysfunction, and significantly improved cell viability and/or renal morphology, whereas DecylTPP treatment did not offer any protection. These findings implicate that MitoQ could potentially be of therapeutic use for reducing organ preservation damage and kidney discardment and/or possibly improving renal function after transplantation. PMID:21159749

The mitochondria-targeted antioxidant mitoquinone protects against cold storage injury of renal tubular cells and rat kidneys.

PubMed

Mitchell, Tanecia; Rotaru, Dumitru; Saba, Hamida; Smith, Robin A J; Murphy, Michael P; MacMillan-Crow, Lee Ann

2011-03-01

The majority of kidneys used for transplantation are obtained from deceased donors. These kidneys must undergo cold preservation/storage before transplantation to preserve tissue quality and allow time for recipient selection and transport. However, cold storage (CS) can result in tissue injury, kidney discardment, or long-term renal dysfunction after transplantation. We have previously determined mitochondrial superoxide and other downstream oxidants to be important signaling molecules that contribute to CS plus rewarming (RW) injury of rat renal proximal tubular cells. Thus, this study's purpose was to determine whether adding mitoquinone (MitoQ), a mitochondria-targeted antioxidant, to University of Wisconsin (UW) preservation solution could offer protection against CS injury. CS was initiated by placing renal cells or isolated rat kidneys in UW solution alone (4 h at 4°C) or UW solution containing MitoQ or its control compound, decyltriphenylphosphonium bromide (DecylTPP) (1 μM in vitro; 100 μM ex vivo). Oxidant production, mitochondrial function, cell viability, and alterations in renal morphology were assessed after CS exposure. CS induced a 2- to 3-fold increase in mitochondrial superoxide generation and tyrosine nitration, partial inactivation of mitochondrial complexes, and a significant increase in cell death and/or renal damage. MitoQ treatment decreased oxidant production ~2-fold, completely prevented mitochondrial dysfunction, and significantly improved cell viability and/or renal morphology, whereas DecylTPP treatment did not offer any protection. These findings implicate that MitoQ could potentially be of therapeutic use for reducing organ preservation damage and kidney discardment and/or possibly improving renal function after transplantation.

Prevention of Trauma/Hemorrhagic Shock-Induced Mortality, Apoptosis, Inflammation and Mitochondrial Dysfunction Using IL-6 as a Resuscitation Adjuvant

DTIC Science & Technology

2011-12-01

infiltrating PMNs is not merely limited to organs that have been directly injured from trauma. Ischemia - reperfusion injury (which occurs after... injury by facilitating inflammatory cell adhesion in an animal model of myocardial ischemia - reperfusion [61,62]. Fabp2 and Fabp5 have been implicated in...Bauer A, Tweardy DJ (1998) Activation of STAT proteins following ischemia reperfusion injury demonstrates a distinct IL- 6 and G-CSF mediated profile

8-pCPT-cGMP prevents mitochondrial depolarization and improves the outcome of steatotic partial liver transplantation

PubMed Central

Liu, Qinlong; Rehman, Hasibur; Krishnasamy, Yasodha; Lemasters, John J; Zhong, Zhi

2017-01-01

Permeant cGMP analogs prevent the mitochondria permeability transition (MPT) in vitro. In this study, we explored whether 8-pCPT-cGMP prevents the MPT and decreases post-transplant damage to fatty partial liver grafts (FPG) in vivo. Rats were fed a control or high-fat, high-fructose diet for 2-week. Lean and fatty liver explants were reduced in size ex vivo to ~35% and stored in the University of Wisconsin solution with and without 8-pCPT-cGMP (300 µM) for 2 h. After transplantation, alanine aminotransferase release (indicator of hepatocellular injury), hyperbilirubinemia (indicator of poor liver function), and cell death were all higher in FPG than in lean partial grafts (LPG). Liver regeneration increased in LPG but was suppressed in FPG. 8-pCPT-cGMP blunted graft injury, improved liver regeneration and function, and increased survival of FPG. Hepatic mitochondrial depolarization detected by intravital multiphoton microscopy of rhodamine 123 in living rats was ~3.5-fold higher in FPG than in LPG. 8-pCPT-cGMP decreased mitochondrial depolarization in FPG almost to the level of LPG. Activation of mammalian target of rapamycin (mTOR), an energy sensitive kinase that stimulates cell proliferation and growth, and p70S6 kinase, a downstream signaling molecule of mTOR, was increased in LPG but suppressed in FPG. 8-pCPT-cGMP restored the activity of mTOR and p70S6 kinase in FPG. 8-pCPT-cGMP also increased activation of cAMP response element-binding protein (CREB) and expression of cyclins D1 and E in FPG. Non-alcoholic steatosis increases injury and suppresses regeneration after partial liver transplantation, at least in part, due to more severe mitochondrial dysfunction. Protection of mitochondria with a cGMP analog effectively improves outcomes of FPG transplantation. PMID:28694919

Prevention of Trauma/Hemorrhagic Shock-Induced Mortality,Apoptosis, Inflammation and Mitochondrial Dysfunction

DTIC Science & Technology

2013-12-01

suggesting another mechanism for the apoptosis-reduction benefit of IL-6 signaling, and 7) Stat3. can substitute for Stat3. to restore mitochondrial...Rats subjected to femur fracture and T-HS (AIM 2) and 3) Swine subjected to laparotomy, splenectomy, tissue injury and controlled HS (AIM 3). Aim...unacceptable mortality during the shock phase, the second was that there was variable amounts of bleeding from the femoral fracture site. We opted based on

Flurbiprofen, a Cyclooxygenase Inhibitor, Protects Mice from Hepatic Ischemia/Reperfusion Injury by Inhibiting GSK-3β Signaling and Mitochondrial Permeability Transition

PubMed Central

Fu, Hailong; Chen, Huan; Wang, Chengcai; Xu, Haitao; Liu, Fang; Guo, Meng; Wang, Quanxing; Shi, Xueyin

2012-01-01

Flurbiprofen acts as a nonselective inhibitor for cyclooxygenases (COX-1 and COX-2), but its impact on hepatic ischemia/reperfusion (I/R) injury remains unclear. Mice were randomized into sham, I/R and flurbiprofen (Flurb) groups. The hepatic artery and portal vein to the left and median liver lobes were occluded for 90 min and unclamped for reperfusion to establish a model of segmental (70%) warm hepatic ischemia. Pretreatment of animals with flurbiprofen prior to I/R insult significantly decreased serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), and prevented hepatocytes from I/R-induced apoptosis/necrosis. Moreover, flurbiprofen dramatically inhibited mitochondrial permeability transition (MPT) pore opening, and thus prevented mitochondrial-related cell death and apoptosis. Mechanistic studies revealed that flurbiprofen markedly inhibited glycogen synthase kinase (GSK)-3β activity and increased phosphorylation of GSK-3β at Ser9, which, consequently, could modulate the adenine nucleotide translocase (ANT)–cyclophilin D (CyP-D) complex and the susceptibility to MPT induction. Therefore, administration of flurbiprofen prior to hepatic I/R ameliorates mitochondrial and hepatocellular damage through inhibition of MPT and inactivation of GSK-3β, and provides experimental evidence for clinical use of flurbiprofen to protect liver function in surgical settings in addition to its conventional use for pain relief. PMID:22714712

Carbamazepine suppresses calpain-mediated autophagy impairment after ischemia/reperfusion in mouse livers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jae-Sung, E-mail: Jae.Kim@surgery.ufl.edu; Wang, Jin-Hee, E-mail: jin-hee.wang@surgery.ufl.edu; Biel, Thomas G., E-mail: Thomas.Biel@surgery.ufl.edu

Onset of the mitochondrial permeability transition (MPT) plays a causative role in ischemia/reperfusion (I/R) injury. Current therapeutic strategies for reducing reperfusion injury remain disappointing. Autophagy is a lysosome-mediated, catabolic process that timely eliminates abnormal or damaged cellular constituents and organelles such as dysfunctional mitochondria. I/R induces calcium overloading and calpain activation, leading to degradation of key autophagy-related proteins (Atg). Carbamazepine (CBZ), an FDA-approved anticonvulsant drug, has recently been reported to increase autophagy. We investigated the effects of CBZ on hepatic I/R injury. Hepatocytes and livers from male C57BL/6 mice were subjected to simulated in vitro, as well as in vivomore » I/R, respectively. Cell death, intracellular calcium, calpain activity, changes in autophagy-related proteins (Atg), autophagic flux, MPT and mitochondrial membrane potential after I/R were analyzed in the presence and absence of 20 μM CBZ. CBZ significantly increased hepatocyte viability after reperfusion. Confocal microscopy revealed that CBZ prevented calcium overloading, the onset of the MPT and mitochondrial depolarization. Immunoblotting and fluorometric analysis showed that CBZ blocked calpain activation, depletion of Atg7 and Beclin-1 and loss of autophagic flux after reperfusion. Intravital multiphoton imaging of anesthetized mice demonstrated that CBZ substantially reversed autophagic defects and mitochondrial dysfunction after I/R in vivo. In conclusion, CBZ prevents calcium overloading and calpain activation, which, in turn, suppresses Atg7 and Beclin-1 depletion, defective autophagy, onset of the MPT and cell death after I/R. - Highlights: • A mechanism of carbamazepine (CBZ)-induced cytoprotection in livers is proposed. • Impaired autophagy is a key event contributing to lethal reperfusion injury. • The importance of autophagy is extended and confirmed in an in vivo model. • CBZ is a potential agent to improve liver function after liver surgery.« less

Curcumin micelles improve mitochondrial function in neuronal PC12 cells and brains of NMRI mice - Impact on bioavailability.

PubMed

Hagl, Stephanie; Kocher, Alexa; Schiborr, Christina; Kolesova, Natalie; Frank, Jan; Eckert, Gunter P

2015-10-01

Curcumin, a polyphenolic compound abundant in the rhizome of Curcuma longa, has been reported to have various beneficial biological and pharmacological activities. Recent research revealed that curcumin might be valuable in the prevention and therapy of numerous disorders including neurodegenerative diseases like Alzheimer's disease. Due to its low absorption and quick elimination from the body, curcumin bioavailability is rather low which poses major problems for the use of curcumin as a therapeutic agent. There are several approaches to ameliorate curcumin bioavailability after oral administration, amongst them simultaneous administration with secondary plant compounds, micronization and micellation. We examined bioavailability in vivo in NMRI mice and the effects of native curcumin and a newly developed curcumin micelles formulation on mitochondrial function in vitro in PC12 cells and ex vivo in isolated mouse brain mitochondria. We found that curcumin micelles improved bioavailability of native curcumin around 10- to 40-fold in plasma and brain of mice. Incubation with native curcumin and curcumin micelles prevented isolated mouse brain mitochondria from swelling, indicating less mitochondrial permeability transition pore (mPTP) opening and prevention of injury. Curcumin micelles proved to be more efficient in preventing mitochondrial swelling in isolated mouse brain mitochondria and protecting PC12 cells from nitrosative stress than native curcumin. Due to their improved effectivity, curcumin micelles might be a suitable formulation for the prevention of mitochondrial dysfunction in brain aging and neurodegeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fructose 1-6 bisphosphate versus University of Wisconsin solution for rat liver preservation: does FBP prevent early mitochondrial injury?

PubMed

de Fraga, R S; Heinen, P E T; Kruel, C R P; Molin, S D; Mota, S M; Cerski, C T S; Gasperin, G; Souto, A A; de Oliveira, J R; Alvares-da-Silva, M R

2011-06-01

Fructose 1,6-biphosphate (FBP) has been shown to exert therapeutic effects in models of ischemia-reperfusion in organs other than the liver. This study compared FBP and University of Wisconsin (UW) solution during cold storage and reperfusion, among mitochondria of adult male Wistar rat livers. Adult male Wistar rats were assigned to two groups according to the preservation solution used; UW or FBP Aspartate transaminase (AST), alanine transferase (ALT); and lactic dehydrogenase (LDH) were measured in samples of the storage solution obtained at 2, 4 and 6 hours of preservation. After 6 hours of cold storage, we reperfused the liver, taking blood samples to measure AST, ALT, LDH, and throbarbituric acid reactive substances (TBARS). Hepatic fragments were processed for histologic analysis; for determinations of TBARS, catalase, and nitric oxide as well as for mitochondrial evaluation by infrared spectroscopy. During cold preservation, levels of AST and LDH in the storage solution were lower among the FBP group, but after reperfusion, serum levels of AST, ALT, and LDH were higher in this group, as was catalase activity. TBARS and nitric oxide were comparable between the groups. In the UW group there was a higher amide I/amide II ratio than in the FBP group, suggesting an abnormal protein structure of the mitochondrial membrane. No signs of preservation injury were observed in any liver biopsy, but sinusoidal congestion was present in livers preserved with FBP. FBP showed a protective effect for preservation during cold storage seeming to protect the mitochondrial membrane although it did not prevent reperfusion injury. Copyright © 2011 Elsevier Inc. All rights reserved.

Vitamin E confers cytoprotective effects on cardiomyocytes under conditions of heat stress by increasing the expression of metallothionein.

PubMed

Wang, Xiaowu; Dong, Wenpeng; Yuan, Binbin; Yang, Yongchao; Yang, Dongpeng; Lin, Xi; Chen, Changfu; Zhang, Weida

2016-05-01

Heat stress (HS) is commonly used to refer to the heat load that an individual is subjected to due to either metabolic heat, or environmental factors, including high temperatures and high humidity levels. HS has been reported to affect and even damage the functioning of various organs; overexposure to high temperatures and high humidity may lead to accidental deaths. It has been suggested that the cardiovascular system is primarily targeted by exposure to HS conditions; the HS-induced dysfunction of cardiomyocytes, which is characterized by mitochondrial dysfunction, may result in the development of cardiovascular diseases. The excessive production of reactive oxygen species (ROS) also participates in mitochondrial dysfunction. However, effective methods for the prevention and treatment of mitochondrial and cardiovascular dysfunction induced by exposure to HS are lacking. In the present study, we hypothesized that vitamin E (VE), an antioxidant, is capable of preventing oxidative stress and mitochondrial injury in cardiomyocytes induced by exposure to HS. The results revealed that pre‑treatment with VE increased the expression of metallothionein (MT), which has previously been reported to confer cytoprotective effects, particularly on the cardiovascular system. Pre-treatment with VE restored mitochondrial function in cardiomyocytes under conditions of HS by increasing the expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), and by increasing adenosine triphosphate (ATP) levels. Furthermore, pre-treatment with VE decreased the production of ROS, which was induced by exposure to HS and thus exerted antioxidant effects. In addition, pre-treatment with VE attenuated oxidative stress induced by exposure to HS, as demonstrated by the increased levels of antioxidant enzymes [superoxide dismutase (SOD) and glutathione (GSH)], and by the decreased levels of markers of oxidative injury [malondialdehyde (MDA) and lactate dehydrogenase (LDH)]. Taken together, these findings suggest that pre-treatment with VE can prevent mitochondrial dysfunction and oxidative stress in cardiomyocytes induced by exposure to HS, by increasing the expression of MT.

Reduction in Autophagy by (-)-Epigallocatechin-3-Gallate (EGCG): a Potential Mechanism of Prevention of Mitochondrial Dysfunction After Subarachnoid Hemorrhage.

PubMed

Chen, Ying; Huang, Liyong; Zhang, Huiyong; Diao, Xiling; Zhao, Shuyang; Zhou, Wenke

2017-01-01

Mitochondrial dysfunction and subsequent autophagy, which are common features in central nervous system (CNS) disorders, were found to contribute to neuronal cell injury after subarachnoid hemorrhage (SAH). (-)-Epigallocatechin-3-gallate (EGCG), the main biological active of tea catechin, is well known for its beneficial effects in the treatment of CNS diseases. Here, the ability of EGCG to rescue cellular injury and mitochondrial function following the improvement of autophagic flux after SAH was investigated. As expected, EGCG-protected mitochondrial function depended on the inhibition of cytosolic Ca 2+ concentration ([Ca 2+ ] i ) influx via voltage-gated calcium channels (VGCCs) and, consequently, mitochondrial Ca 2+ concentration ([Ca 2+ ] m ) overload via mitochondrial Ca 2+ uniporter (MCU). The attenuated [Ca 2+ ] i and [Ca 2+ ] m levels observed in the EGCG-treated group likely lessened oxyhemoglobin (OxyHb)-induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondrial membrane permeability transition pore (mPTP) opening, reactive oxygen species (ROS), and cytochrosome c (cyt c) releasing. Subsequently, EGCG can restore the disrupted autophagy flux after SAH both at the initiation and formation stages by regulating Atg5, LC3B, and Becn-1 (Beclin-1) mRNA expressions. Thus, precondition EGCG resulted in autophagosomes and more autolysosomes compared with SAH group. As a result, EGCG pre-treatment increased the neurological score and decreased cell death. This study suggested that the mitochondrial dysfunction and abnormal autophagy flux synergistically contribute to SAH pathogenesis. Thus, EGCG can be regarded as a new pharmacological agent that targets both mitochondria and altered autophagy in SAH therapy.

Thiamine preserves mitochondrial function in a rat model of traumatic brain injury, preventing inactivation of the 2-oxoglutarate dehydrogenase complex.

PubMed

Mkrtchyan, Garik V; Üçal, Muammer; Müllebner, Andrea; Dumitrescu, Sergiu; Kames, Martina; Moldzio, Rudolf; Molcanyi, Marek; Schaefer, Samuel; Weidinger, Adelheid; Schaefer, Ute; Hescheler, Juergen; Duvigneau, Johanna Catharina; Redl, Heinz; Bunik, Victoria I; Kozlov, Andrey V

2018-05-16

Based on the fact that traumatic brain injury is associated with mitochondrial dysfunction we aimed at localization of mitochondrial defect and attempted to correct it by thiamine. Interventional controlled experimental animal study was used. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion traumatic brain injury. Thiamine was administered 1 h prior to trauma; cortex was extracted for analysis 4 h and 3 d after trauma. Increased expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor receptor 1 (TNF-R1) by 4 h was accompanied by a decrease in mitochondrial respiration with glutamate but neither with pyruvate nor succinate. Assays of TCA cycle flux-limiting 2-oxoglutarate dehydrogenase complex (OGDHC) and functionally linked enzymes (glutamate dehydrogenase, glutamine synthetase, pyruvate dehydrogenase, malate dehydrogenase and malic enzyme) indicated that only OGDHC activity was decreased. Application of the OGDHC coenzyme precursor thiamine rescued the activity of OGDHC and restored mitochondrial respiration. These effects were not mediated by changes in the expression of the OGDHC sub-units (E1k and E3), suggesting post-translational mechanism of thiamine effects. By the third day after TBI, thiamine treatment also decreased expression of TNF-R1. Specific markers of unfolded protein response did not change in response to thiamine. Our data point to OGDHC as a major site of damage in mitochondria upon traumatic brain injury, which is associated with neuroinflammation and can be corrected by thiamine. Further studies are required to evaluate the pathological impact of these findings in clinical settings. Copyright © 2018. Published by Elsevier B.V.

A TSPO ligand prevents mitochondrial sterol accumulation and dysfunction during myocardial ischemia-reperfusion in hypercholesterolemic rats.

PubMed

Musman, Julien; Paradis, Stéphanie; Panel, Mathieu; Pons, Sandrine; Barau, Caroline; Caccia, Claudio; Leoni, Valerio; Ghaleh, Bijan; Morin, Didier

2017-10-15

A major cause of cell death during myocardial ischemia-reperfusion is mitochondrial dysfunction. We previously showed that the reperfusion of an ischemic myocardium was associated with an accumulation of cholesterol into mitochondria and a concomitant strong generation of auto-oxidized oxysterols. The inhibition of mitochondrial accumulation of cholesterol abolished the formation of oxysterols and prevented mitochondrial injury at reperfusion. The aim of this study was to investigate the impact of hypercholesterolemia on sterol and oxysterol accumulation in rat cardiac cytosols and mitochondria and to analyse the effect of the translocator protein ligand 4'-chlorodiazepam on this accumulation and mitochondrial function. Hypercholesterolemic ZDF fa/fa rats or normocholesterolemic lean rats were submitted to 30min of coronary artery occlusion followed by 15min reperfusion where cardiac cytosols and mitochondria were isolated. Hypercholesterolemia increased the cellular cardiac concentrations of cholesterol, cholesterol precursors and oxysterols both in cytosol and mitochondria in non-ischemic conditions. It also amplified the accumulation of all these compounds in cardiac cells and the alteration of mitochondrial function with ischemia-reperfusion. Administration of 4'-chlorodiazepam to ZDF fa/fa rats had no effect on the enhancement of sterols and oxysterols observed in the cytosols but inhibited cholesterol transfer to the mitochondria. It also alleviated the mitochondrial accumulation of all the investigated sterols and oxysterols. This was associated with a restoration of oxidative phosphorylation and a prevention of mitochondrial transition pore opening. The inhibition of cholesterol accumulation with TSPO ligands represents an interesting strategy to protect the mitochondria during ischemia-reperfusion in hypercholesterolemic conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Inhibition of NAADP signalling on reperfusion protects the heart by preventing lethal calcium oscillations via two-pore channel 1 and opening of the mitochondrial permeability transition pore.

PubMed

Davidson, Sean M; Foote, Kirsty; Kunuthur, Suma; Gosain, Raj; Tan, Noah; Tyser, Richard; Zhao, Yong Juan; Graeff, Richard; Ganesan, A; Duchen, Michael R; Patel, Sandip; Yellon, Derek M

2015-12-01

In the heart, a period of ischaemia followed by reperfusion evokes powerful cytosolic Ca(2+) oscillations that can cause lethal cell injury. These signals represent attractive cardioprotective targets, but the underlying mechanisms of genesis are ill-defined. Here, we investigated the role of the second messenger nicotinic acid adenine dinucleotide phosphate (NAADP), which is known in several cell types to induce Ca(2+) oscillations that initiate from acidic stores such as lysosomes, likely via two-pore channels (TPCs, TPC1 and 2). An NAADP antagonist called Ned-K was developed by rational design based on a previously existing scaffold. Ned-K suppressed Ca(2+) oscillations and dramatically protected cardiomyocytes from cell death in vitro after ischaemia and reoxygenation, preventing opening of the mitochondrial permeability transition pore. Ned-K profoundly decreased infarct size in mice in vivo. Transgenic mice lacking the endo-lysosomal TPC1 were also protected from injury. NAADP signalling plays a major role in reperfusion-induced cell death and represents a potent pathway for protection against reperfusion injury. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Inhibition of NAADP signalling on reperfusion protects the heart by preventing lethal calcium oscillations via two-pore channel 1 and opening of the mitochondrial permeability transition pore

PubMed Central

Davidson, Sean M.; Foote, Kirsty; Kunuthur, Suma; Gosain, Raj; Tan, Noah; Tyser, Richard; Zhao, Yong Juan; Graeff, Richard; Ganesan, A.; Duchen, Michael R.; Patel, Sandip; Yellon, Derek M.

2015-01-01

Aims In the heart, a period of ischaemia followed by reperfusion evokes powerful cytosolic Ca2+ oscillations that can cause lethal cell injury. These signals represent attractive cardioprotective targets, but the underlying mechanisms of genesis are ill-defined. Here, we investigated the role of the second messenger nicotinic acid adenine dinucleotide phosphate (NAADP), which is known in several cell types to induce Ca2+ oscillations that initiate from acidic stores such as lysosomes, likely via two-pore channels (TPCs, TPC1 and 2). Methods and results An NAADP antagonist called Ned-K was developed by rational design based on a previously existing scaffold. Ned-K suppressed Ca2+ oscillations and dramatically protected cardiomyocytes from cell death in vitro after ischaemia and reoxygenation, preventing opening of the mitochondrial permeability transition pore. Ned-K profoundly decreased infarct size in mice in vivo. Transgenic mice lacking the endo-lysosomal TPC1 were also protected from injury. Conclusion NAADP signalling plays a major role in reperfusion-induced cell death and represents a potent pathway for protection against reperfusion injury. PMID:26395965

The effect of mitochondrial calcium uniporter on mitochondrial fission in hippocampus cells ischemia/reperfusion injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Lantao; Li, Shuhong; Wang, Shilei, E-mail: wshlei@aliyun.com

The mitochondrial calcium uniporter (MCU) transports free Ca{sup 2+} into the mitochondrial matrix, maintaining Ca{sup 2+} homeostasis, thus regulates the mitochondrial morphology. Previous studies have indicated that there was closely crosstalk between MCU and mitochondrial fission during the process of ischemia/reperfusion injury. This study constructed a hypoxia reoxygenation model using primary hippocampus neurons to mimic the cerebral ischemia/reperfusion injury and aims to explore the exactly effect of MCU on the mitochondrial fission during the process of ischemia/reperfusion injury and so as the mechanisms. Our results found that the inhibitor of the MCU, Ru360, decreased mitochondrial Ca{sup 2+} concentration, suppressed themore » expression of mitochondrial fission protein Drp1, MIEF1 and Fis1, and thus improved mitochondrial morphology significantly. Whereas spermine, the agonist of the MCU, had no significant impact compared to the I/R group. This study demonstrated that the MCU regulates the process of mitochondrial fission by controlling the Ca{sup 2+} transport, directly upregulating mitochondrial fission proteins Drp1, Fis1 and indirectly reversing the MIEF1-induced mitochondrial fusion. It also provides new targets for brain protection during ischemia/reperfusion injury. - Highlights: • We study MCU with primary neuron culture. • MCU induces mitochondrial fission. • MCU reverses MIEF1 effect.« less

Brain injury with diabetes mellitus: evidence, mechanisms and treatment implications.

PubMed

Hamed, Sherifa A

2017-04-01

Diabetes mellitus is a risk for brain injury. Brain injury is associated with acute and chronic hyperglycaemia, insulin resistance, hyperinsulinemia, diabetic ketoacidosis (DKA) and hypoglycaemic events in diabetic patients. Hyperglycemia is a cause of cognitive deterioration, low intelligent quotient, neurodegeneration, brain aging, brain atrophy and dementia. Areas covered: The current review highlights the experimental, clinical, neuroimaging and neuropathological evidence of brain injury induced by diabetes and its associated metabolic derangements. It also highlights the mechanisms of diabetes-induced brain injury. It seems that the pathogenesis of hyperglycemia-induced brain injury is complex and includes combination of vascular disease, oxidative stress, neuroinflammation, mitochondrial dysfunction, apoptosis, reduction of neurotrophic factors, acetylcholinesterase (AChE) activation, neurotransmitters' changes, impairment of brain repair processes, impairment of brain glymphatic system, accumulation of amyloid β and tau phosphorylation and neurodegeneration. The potentials for prevention and treatment are also discussed. Expert commentary: We summarize the risks and the possible mechanisms of DM-induced brain injury and recommend strategies for neuroprotection and neurorestoration. Recently, a number of drugs and substances [in addition to insulin and its mimics] have shown promising potentials against diabetes-induced brain injury. These include: antioxidants, neuroinflammation inhibitors, anti-apoptotics, neurotrophic factors, AChE inhibitors, mitochondrial function modifiers and cell based therapies.

Liraglutide alleviates H2O2-induced retinal ganglion cells injury by inhibiting autophagy through mitochondrial pathways.

PubMed

Ma, Xuefei; Lin, Wenjian; Lin, Zhenyu; Hao, Ming; Gao, Xinyuan; Zhang, Yue; Kuang, Hongyu

2017-06-01

Retinal ganglion cells (RGCs), which exist in the inner retina, are the retinal neurons which can be damaged in the early stage of diabetic retinopathy (DR). Liraglutide, a glucagon-like peptide-1 (GLP-1) analog, exerts biological functions by binding the receptor (GLP-1R), the expression of which in RGC-5 cells was first shown by our team in 2012. It was reported that liraglutide prevented retinal neurodegeneration in diabetic subjects. However, the involvement of mechanisms such as autophagy and mitochondrial balance in liraglutide-induced retinal protection is unknown. Here, we aimed to investigate the protective effects of liraglutide and explore the potential mechanisms of liraglutide-induced retinal RGC protection. RGC-5 cells were treated with H 2 O 2 and/or liraglutide. Cell viability was detected with the CCK-8 kit. The axon marker GAP43, autophagy and mitophagy indicators LC3A/B, Beclin-1, p62, Parkin, BCL2/Adenovirus E1B 19kDa protein-interacting protein 3-like (BNIP3L) and the key regulator of mitochondrial biogenesis PGC-1α were examined via western blot analysis. Autophagy was also evaluated using the ImageXpress Micro XLS system and transmission electron microscopy (TEM). Reactive oxygen species (ROS), mitochondrial membrane potential and fluorescent staining for mitochondria were also measured using the ImageXpress Micro XLS system. Our results showed that pretreatment with liraglutide significantly prevented H 2 O 2 -induced cell viability decline, mitochondrial morphological deterioration and induction of autophagy, which appeared as increased expression of LC3 II/I and Beclin-1, along with p62 degradation. Moreover, liraglutide suppressed the H 2 O 2 -induced decline in GAP43 expression, thus protecting cells. However, rapamycin induced autophagy and blocked the protective process. Liraglutide also provided mitochondrial protection and appeared to alleviate H 2 O 2 -induced ROS overproduction and a decline in mitochondrial membrane potential, partially by promoting mitochondrial generation and attenuating mitophagy. In conclusion, liraglutide attenuates H 2 O 2 induced RGC-5 cell injury by inhibiting autophagy through maintaining a balance between mitochondrial biogenesis and mitophagy. Copyright © 2017 Elsevier Inc. All rights reserved.

TRO40303 Ameliorates Alcohol-Induced Pancreatitis Through Reduction of Fatty Acid Ethyl Ester–Induced Mitochondrial Injury and Necrotic Cell Death

PubMed Central

Javed, Muhammad Ahsan; Wen, Li; Awais, Muhammad; Latawiec, Diane; Huang, Wei; Chvanov, Michael; Schaller, Sophie; Bordet, Thierry; Michaud, Magali; Pruss, Rebecca; Tepikin, Alexei; Criddle, David; Sutton, Robert

2018-01-01

Objectives Mitochondrial permeability transition pore inhibition is a promising approach to treat acute pancreatitis (AP). We sought to determine (i) the effects of the mitochondrial permeability transition pore inhibitor 3,5-seco-4-nor-cholestan-5-one oxime-3-ol (TRO40303) on murine and human pancreatic acinar cell (PAC) injury induced by fatty acid ethyl esters (FAEEs) or taurolithocholic acid-3-sulfate and (ii) TRO40303 pharmacokinetics and efficacy in experimental alcoholic AP (FAEE-AP). Methods Changes in mitochondrial membrane potential (Δψm), cytosolic Ca2+ ([Ca2+]c), and cell fate were examined in freshly isolated murine or human PACs by confocal microscopy. TRO40303 pharmacokinetics were assessed in cerulein-induced AP and therapeutic efficacy in FAEE-AP induced with palmitoleic acid and ethanol. Severity of AP was assessed by standard biomarkers and blinded histopathology. Results TRO40303 prevented loss of Δψm and necrosis induced by 100 μM palmitoleic acid ethyl ester or 500 μM taurolithocholic acid-3-sulfate in murine and human PACs. Pharmacokinetic analysis found TRO40303 accumulated in the pancreas. A single dose of 3 mg/kg TRO40303 significantly reduced serum amylase (P = 0.043), pancreatic trypsin (P = 0.018), and histopathology scores (P = 0.0058) in FAEE-AP. Conclusions TRO40303 protects mitochondria and prevents necrotic cell death pathway activation in murine and human PACs, ameliorates the severity of FAEE-AP, and is a candidate drug for human AP. PMID:29200128

Mitochondrial dysfunction and tissue injury by alcohol, high fat, nonalcoholic substances and pathological conditions through post-translational protein modifications

PubMed Central

Song, Byoung-Joon; Akbar, Mohammed; Abdelmegeed, Mohamed A.; Byun, Kyunghee; Lee, Bonghee; Yoon, Seung Kew; Hardwick, James P.

2014-01-01

Mitochondria are critically important in providing cellular energy ATP as well as their involvement in anti-oxidant defense, fat oxidation, intermediary metabolism and cell death processes. It is well-established that mitochondrial functions are suppressed when living cells or organisms are exposed to potentially toxic agents including alcohol, high fat diets, smoking and certain drugs or in many pathophysiological states through increased levels of oxidative/nitrative stress. Under elevated nitroxidative stress, cellular macromolecules proteins, DNA, and lipids can undergo different oxidative modifications, leading to disruption of their normal, sometimes critical, physiological functions. Recent reports also indicated that many mitochondrial proteins are modified via various post-translation modifications (PTMs) and primarily inactivated. Because of the recently-emerging information, in this review, we specifically focus on the mechanisms and roles of five major PTMs (namely oxidation, nitration, phosphorylation, acetylation, and adduct formation with lipid-peroxides, reactive metabolites, or advanced glycation end products) in experimental models of alcoholic and nonalcoholic fatty liver disease as well as acute hepatic injury caused by toxic compounds. We also highlight the role of the ethanol-inducible cytochrome P450-2E1 (CYP2E1) in some of these PTM changes. Finally, we discuss translational research opportunities with natural and/or synthetic anti-oxidants, which can prevent or delay the onset of mitochondrial dysfunction, fat accumulation and tissue injury. PMID:25465468

Renal Tubular Cell Mitochondrial Dysfunction Occurs Despite Preserved Renal Oxygen Delivery in Experimental Septic Acute Kidney Injury

PubMed Central

Pollen, Sean; Greco, Elisabetta; Courtneidge, Holly; Hall, Andrew M.; Duchen, Michael R.; Tam, Frederick W. K.; Unwin, Robert J.; Singer, Mervyn

2018-01-01

Objective: To explain the paradigm of significant renal functional impairment despite preserved hemodynamics and histology in sepsis-induced acute kidney injury. Design: Prospective observational animal study. Setting: University research laboratory. Subjects: Male Wistar rats. Intervention: Using a fluid-resuscitated sublethal rat model of fecal peritonitis, changes in renal function were characterized in relation to global and renal hemodynamics, and histology at 6 and 24 hours (n = 6–10). Sham-operated animals were used as comparison (n = 8). Tubular cell mitochondrial function was assessed using multiphoton confocal imaging of live kidney slices incubated in septic serum. Measurements and Main Results: By 24 hours, serum creatinine was significantly elevated with a concurrent decrease in renal lactate clearance in septic animals compared with sham-operated and 6-hour septic animals. Renal uncoupling protein-2 was elevated in septic animals at 24 hours although tubular cell injury was minimal and mitochondrial ultrastructure in renal proximal tubular cells preserved. There was no significant change in global or renal hemodynamics and oxygen delivery/consumption between sham-operated and septic animals at both 6- and 24-hour timepoints. In the live kidney slice model, mitochondrial dysfunction was seen in proximal tubular epithelial cells incubated with septic serum with increased production of reactive oxygen species, and decreases in nicotinamide adenine dinucleotide and mitochondrial membrane potential. These effects were prevented by coincubation with the reactive oxygen species scavenger, 4-hydroxy-2,2,6,6-tetramethyl-piperidin-1-oxyl. Conclusions: Renal dysfunction in sepsis occurs independently of hemodynamic instability or structural damage. Mitochondrial dysfunction mediated by circulating mediators that induce local oxidative stress may represent an important pathophysiologic mechanism. PMID:29293148

Inhibition of MCU forces extramitochondrial adaptations governing physiological and pathological stress responses in heart

PubMed Central

Rasmussen, Tyler P.; Wu, Yuejin; Joiner, Mei-ling A.; Koval, Olha M.; Wilson, Nicholas R.; Luczak, Elizabeth D.; Wang, Qinchuan; Chen, Biyi; Gao, Zhan; Zhu, Zhiyong; Wagner, Brett A.; Soto, Jamie; McCormick, Michael L.; Kutschke, William; Weiss, Robert M.; Yu, Liping; Boudreau, Ryan L.; Abel, E. Dale; Zhan, Fenghuang; Spitz, Douglas R.; Buettner, Garry R.; Song, Long-Sheng; Zingman, Leonid V.; Anderson, Mark E.

2015-01-01

Myocardial mitochondrial Ca2+ entry enables physiological stress responses but in excess promotes injury and death. However, tissue-specific in vivo systems for testing the role of mitochondrial Ca2+ are lacking. We developed a mouse model with myocardial delimited transgenic expression of a dominant negative (DN) form of the mitochondrial Ca2+ uniporter (MCU). DN-MCU mice lack MCU-mediated mitochondrial Ca2+ entry in myocardium, but, surprisingly, isolated perfused hearts exhibited higher O2 consumption rates (OCR) and impaired pacing induced mechanical performance compared with wild-type (WT) littermate controls. In contrast, OCR in DN-MCU–permeabilized myocardial fibers or isolated mitochondria in low Ca2+ were not increased compared with WT, suggesting that DN-MCU expression increased OCR by enhanced energetic demands related to extramitochondrial Ca2+ homeostasis. Consistent with this, we found that DN-MCU ventricular cardiomyocytes exhibited elevated cytoplasmic [Ca2+] that was partially reversed by ATP dialysis, suggesting that metabolic defects arising from loss of MCU function impaired physiological intracellular Ca2+ homeostasis. Mitochondrial Ca2+ overload is thought to dissipate the inner mitochondrial membrane potential (ΔΨm) and enhance formation of reactive oxygen species (ROS) as a consequence of ischemia-reperfusion injury. Our data show that DN-MCU hearts had preserved ΔΨm and reduced ROS during ischemia reperfusion but were not protected from myocardial death compared with WT. Taken together, our findings show that chronic myocardial MCU inhibition leads to previously unanticipated compensatory changes that affect cytoplasmic Ca2+ homeostasis, reprogram transcription, increase OCR, reduce performance, and prevent anticipated therapeutic responses to ischemia-reperfusion injury. PMID:26153425

Critical role of free cytosolic calcium, but not uncoupling, in mitochondrial permeability transition and cell death induced by diclofenac oxidative metabolites in immortalized human hepatocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, M.S.; Lim, Priscilla L.K.; Gupta, Rashi

2006-12-15

Diclofenac is a widely used nonsteroidal anti-inflammatory drug that has been associated with rare but serious hepatotoxicity. Experimental evidence indicates that diclofenac targets mitochondria and induces the permeability transition (mPT) which leads to apoptotic cell death in hepatocytes. While the downstream effector mechanisms have been well characterized, the more proximal pathways leading to the mPT are not known. The purpose of this study was to explore the role of free cytosolic calcium (Ca{sup 2+} {sub c}) in diclofenac-induced cell injury in immortalized human hepatocytes. We show that exposure to diclofenac caused time- and concentration-dependent cell injury, which was prevented bymore » the specific mPT inhibitor cyclosporin A (CsA, 5 {mu}M). At 8 h, diclofenac caused increases in [Ca{sup 2+}]{sub c} (Fluo-4 fluorescence), which was unaffected by CsA. Combined exposure to diclofenac/BAPTA (Ca{sup 2+} chelator) inhibited cell injury, indicating that Ca{sup 2+} plays a critical role in precipitating mPT. Diclofenac decreased the mitochondrial membrane potential, {delta}{psi}{sub m} (JC-1 fluorescence), even in the presence of CsA or BAPTA, indicating that mitochondrial depolarization was not a consequence of the mPT or elevated [Ca{sup 2+}]{sub c}. The CYP2C9 inhibitor sulphaphenazole (10 {mu}M) protected from diclofenac-induced cell injury and prevented increases in [Ca{sup 2+}]{sub c}, while it had no effect on the dissipation of the {delta}{psi}{sub m}. Finally, diclofenac exposure greatly increased the mitochondria-selective superoxide levels secondary to the increases in [Ca{sup 2+}]{sub c}. In conclusion, these data demonstrate that diclofenac has direct depolarizing effects on mitochondria which does not lead to cell injury, while CYP2C9-mediated bioactivation causes increases in [Ca{sup 2+}]{sub c}, triggering the mPT and precipitating cell death.« less

Betaine Treatment Attenuates Chronic Ethanol-Induced Hepatic Steatosis and Alterations to the Mitochondrial Respiratory Chain Proteome

PubMed Central

Kharbanda, Kusum K.; Todero, Sandra L.; King, Adrienne L.; Osna, Natalia A.; McVicker, Benita L.; Tuma, Dean J.; Wisecarver, James L.; Bailey, Shannon M.

2012-01-01

Introduction. Mitochondrial damage and disruption in oxidative phosphorylation contributes to the pathogenesis of alcoholic liver injury. Herein, we tested the hypothesis that the hepatoprotective actions of betaine against alcoholic liver injury occur at the level of the mitochondrial proteome. Methods. Male Wister rats were pair-fed control or ethanol-containing liquid diets supplemented with or without betaine (10 mg/mL) for 4-5 wks. Liver was examined for triglyceride accumulation, levels of methionine cycle metabolites, and alterations in mitochondrial proteins. Results. Chronic ethanol ingestion resulted in triglyceride accumulation which was attenuated in the ethanol plus betaine group. Blue native gel electrophoresis (BN-PAGE) revealed significant decreases in the content of the intact oxidative phosphorylation complexes in mitochondria from ethanol-fed animals. The alcohol-dependent loss in many of the low molecular weight oxidative phosphorylation proteins was prevented by betaine supplementation. This protection by betaine was associated with normalization of SAM : S-adenosylhomocysteine (SAH) ratios and the attenuation of the ethanol-induced increase in inducible nitric oxide synthase and nitric oxide generation in the liver. Discussion/Conclusion. In summary, betaine attenuates alcoholic steatosis and alterations to the oxidative phosphorylation system. Therefore, preservation of mitochondrial function may be another key molecular mechanism responsible for betaine hepatoprotection. PMID:22187660

Mitochondrial Reactive Oxygen Species and Kidney Hypoxia in the Development of Diabetic Nephropathy

PubMed Central

Schiffer, Tomas A.; Friederich-Persson, Malou

2017-01-01

The underlying mechanisms in the development of diabetic nephropathy are currently unclear and likely consist of a series of dynamic events from the early to late stages of the disease. Diabetic nephropathy is currently without curative treatments and it is acknowledged that even the earliest clinical manifestation of nephropathy is preceded by an established morphological renal injury that is in turn preceded by functional and metabolic alterations. An early manifestation of the diabetic kidney is the development of kidney hypoxia that has been acknowledged as a common pathway to nephropathy. There have been reports of altered mitochondrial function in the diabetic kidney such as altered mitophagy, mitochondrial dynamics, uncoupling, and cellular signaling through hypoxia inducible factors and AMP-kinase. These factors are also likely to be intertwined in a complex manner. In this review, we discuss how these pathways are connected to mitochondrial production of reactive oxygen species (ROS) and how they may relate to the development of kidney hypoxia in diabetic nephropathy. From available literature, it is evident that early correction and/or prevention of mitochondrial dysfunction may be pivotal in the prevention and treatment of diabetic nephropathy. PMID:28443030

Mitochondrial Reactive Oxygen Species and Kidney Hypoxia in the Development of Diabetic Nephropathy.

PubMed

Schiffer, Tomas A; Friederich-Persson, Malou

2017-01-01

The underlying mechanisms in the development of diabetic nephropathy are currently unclear and likely consist of a series of dynamic events from the early to late stages of the disease. Diabetic nephropathy is currently without curative treatments and it is acknowledged that even the earliest clinical manifestation of nephropathy is preceded by an established morphological renal injury that is in turn preceded by functional and metabolic alterations. An early manifestation of the diabetic kidney is the development of kidney hypoxia that has been acknowledged as a common pathway to nephropathy. There have been reports of altered mitochondrial function in the diabetic kidney such as altered mitophagy, mitochondrial dynamics, uncoupling, and cellular signaling through hypoxia inducible factors and AMP-kinase. These factors are also likely to be intertwined in a complex manner. In this review, we discuss how these pathways are connected to mitochondrial production of reactive oxygen species (ROS) and how they may relate to the development of kidney hypoxia in diabetic nephropathy. From available literature, it is evident that early correction and/or prevention of mitochondrial dysfunction may be pivotal in the prevention and treatment of diabetic nephropathy.

Azilsartan, an angiotensin II type 1 receptor blocker, attenuates tert-butyl hydroperoxide-induced endothelial cell injury through inhibition of mitochondrial dysfunction and anti-inflammatory activity.

PubMed

Liu, Hao; Mao, Ping; Wang, Jia; Wang, Tuo; Xie, Chang-Hou

2016-03-01

Angiotensin II type 1 receptor (AT1-R) blockers protect against brain ischemia by mechanisms dependent on and independent of arterial blood pressure. However, the effects of AT1-R blockers on brain endothelial cell injury and detailed mechanisms remain unclear. The goal of this study is to investigate whether azilsartan, an AT1-R blocker, could attenuate oxidative injury in endothelial cells via regulating mitochondrial function and inflammatory responses. We found that treatment with azilsartan suppressed tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in murine brain endothelial cells (mBECs) by increasing cell viability, decreasing lactate dehydrogenase (LDH) release and inhibiting cell apoptosis. Azilsartan significantly inhibited reactive oxygen species (ROS) generation and lipid peroxidation, but had no effect on antioxidant system. We also detected preserved mitochondrial function after azilsartan treatment, as evidenced by increased mitochondrial membrane potential (MMP), reduced cytochrome c release, preserved ATP synthesis and inhibited mitochondrial swelling. In addition, azilsartan differently regulated expression of inflammatory cytokines and increased the activation of endothelial nitric oxide synthase (eNOS). Pretreatment with eNOS inhibitor L-NIO partially prevented the azilsartan-induced regulation of cytokines and protection. Furthermore, azilsartan-induced protection in our in vitro model was shown to be associated with protein stability of peroxisome proliferator-activated receptor-γ (PPAR-γ). Overall, our data suggest that the AT1-R blocker azilsartan may have therapeutic values in treating endothelial dysfunction associated neurological disorders through anti-oxidative and anti-inflammatory properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mitochondrial-Based Therapeutics for the Treatment of Spinal Cord Injury: Mitochondrial Biogenesis as a Potential Pharmacological Target

PubMed Central

Scholpa, Natalie E.

2017-01-01

Spinal cord injury (SCI) is characterized by an initial trauma followed by a progressive cascade of damage referred to as secondary injury. A hallmark of secondary injury is vascular disruption leading to vasoconstriction and decreased oxygen delivery, which directly reduces the ability of mitochondria to maintain homeostasis and leads to loss of ATP-dependent cellular functions, calcium overload, excitotoxicity, and oxidative stress, further exacerbating injury. Restoration of mitochondria dysfunction during the acute phases of secondary injury after SCI represents a potentially effective therapeutic strategy. This review discusses the past and present pharmacological options for the treatment of SCI as well as current research on mitochondria-targeted approaches. Increased antioxidant activity, inhibition of the mitochondrial permeability transition, alternate energy sources, and manipulation of mitochondrial morphology are among the strategies under investigation. Unfortunately, many of these tactics address single aspects of mitochondrial dysfunction, ultimately proving largely ineffective. Therefore, this review also examines the unexplored therapeutic efficacy of pharmacological enhancement of mitochondrial biogenesis, which has the potential to more comprehensively improve mitochondrial function after SCI. PMID:28935700

Mitochondrial-Based Therapeutics for the Treatment of Spinal Cord Injury: Mitochondrial Biogenesis as a Potential Pharmacological Target.

PubMed

Scholpa, Natalie E; Schnellmann, Rick G

2017-12-01

Spinal cord injury (SCI) is characterized by an initial trauma followed by a progressive cascade of damage referred to as secondary injury. A hallmark of secondary injury is vascular disruption leading to vasoconstriction and decreased oxygen delivery, which directly reduces the ability of mitochondria to maintain homeostasis and leads to loss of ATP-dependent cellular functions, calcium overload, excitotoxicity, and oxidative stress, further exacerbating injury. Restoration of mitochondria dysfunction during the acute phases of secondary injury after SCI represents a potentially effective therapeutic strategy. This review discusses the past and present pharmacological options for the treatment of SCI as well as current research on mitochondria-targeted approaches. Increased antioxidant activity, inhibition of the mitochondrial permeability transition, alternate energy sources, and manipulation of mitochondrial morphology are among the strategies under investigation. Unfortunately, many of these tactics address single aspects of mitochondrial dysfunction, ultimately proving largely ineffective. Therefore, this review also examines the unexplored therapeutic efficacy of pharmacological enhancement of mitochondrial biogenesis, which has the potential to more comprehensively improve mitochondrial function after SCI. U.S. Government work not protected by U.S. copyright.

Tauroursodeoxycholic acid increases neural stem cell pool and neuronal conversion by regulating mitochondria-cell cycle retrograde signaling

PubMed Central

Xavier, Joana M; Morgado, Ana L; Rodrigues, Cecília MP; Solá, Susana

2014-01-01

The low survival and differentiation rates of stem cells after either transplantation or neural injury have been a major concern of stem cell-based therapy. Thus, further understanding long-term survival and differentiation of stem cells may uncover new targets for discovery and development of novel therapeutic approaches. We have previously described the impact of mitochondrial apoptosis-related events in modulating neural stem cell (NSC) fate. In addition, the endogenous bile acid, tauroursodeoxycholic acid (TUDCA) was shown to be neuroprotective in several animal models of neurodegenerative disorders by acting as an anti-apoptotic and anti-oxidant molecule at the mitochondrial level. Here, we hypothesize that TUDCA might also play a role on NSC fate decision. We found that TUDCA prevents mitochondrial apoptotic events typical of early-stage mouse NSC differentiation, preserves mitochondrial integrity and function, while enhancing self-renewal potential and accelerating cell cycle exit of NSCs. Interestingly, TUDCA prevention of mitochondrial alterations interfered with NSC differentiation potential by favoring neuronal rather than astroglial conversion. Finally, inhibition of mitochondrial reactive oxygen species (mtROS) scavenger and adenosine triphosphate (ATP) synthase revealed that the effect of TUDCA is dependent on mtROS and ATP regulation levels. Collectively, these data underline the importance of mitochondrial stress control of NSC fate decision and support a new role for TUDCA in this process. PMID:25483094

Loss of sirtuin 1 and mitofusin 2 contributes to enhanced ischemia/reperfusion injury in aged livers.

PubMed

Chun, Sung Kook; Lee, Sooyeon; Flores-Toro, Joseph; U, Rebecca Y; Yang, Ming-Jim; Go, Kristina L; Biel, Thomas G; Miney, Catherine E; Pierre Louis, Schiley; Law, Brian K; Law, Mary E; Thomas, Elizabeth M; Behrns, Kevin E; Leeuwenburgh, Christiaan; Kim, Jae-Sung

2018-05-17

Ischemia/reperfusion (I/R) injury is a causative factor contributing to morbidity and mortality during liver resection and transplantation. Livers from elderly patients have a poorer recovery from these surgeries, indicating reduced reparative capacity with aging. Mechanisms underlying this age-mediated hypersensitivity to I/R injury remain poorly understood. Here, we investigated how sirtuin 1 (SIRT1) and mitofusin 2 (MFN2) are affected by I/R in aged livers. Young (3 months) and old (23-26 months) male C57/BL6 mice were subjected to hepatic I/R in vivo. Primary hepatocytes isolated from each age group were also exposed to simulated in vitro I/R. Biochemical, genetic, and imaging analyses were performed to assess cell death, autophagy flux, mitophagy, and mitochondrial function. Compared to young mice, old livers showed accelerated liver injury following mild I/R. Reperfusion of old hepatocytes also showed necrosis, accompanied with defective autophagy, onset of the mitochondrial permeability transition, and mitochondrial dysfunction. Biochemical analysis indicated a near-complete loss of both SIRT1 and MFN2 after I/R in old hepatocytes, which did not occur in young cells. Overexpression of either SIRT1 or MFN2 alone in old hepatocytes failed to mitigate I/R injury, while co-overexpression of both proteins promoted autophagy and prevented mitochondrial dysfunction and cell death after reperfusion. Genetic approaches with deletion and point mutants revealed that SIRT1 deacetylated K655 and K662 residues in the C-terminus of MFN2, leading to autophagy activation. The SIRT1-MFN2 axis is pivotal during I/R recovery and may be a novel therapeutic target to reduce I/R injury in aged livers. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Mitochondrial biogenesis in the pulmonary vasculature during inhalation lung injury and fibrosis

EPA Science Inventory

Cell survival and injury repair is facilitated by mitochondrial biogenesis; however, the role of this process in lung repair is unknown. We evaluated mitochondrial biogenesis in the mouse lung in two injuries that cause acute inflammation and in two that cause chronic inflammatio...

Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaja, Ivan; Bai, Xiaowen, E-mail: xibai@mcw.edu; Liu, Yanan

Highlights: • Drp1-mediated increased mitochondrial fission but not fusion is involved the cardiomyocyte death during anoxia-reoxygenation injury. • Reactive oxygen species are upstream initiators of mitochondrial fission. • Increased mitochondrial fission is resulted from Cdk1-, PKCδ-, and calcineurin-mediated Drp1 pathways. - Abstract: Myocardial ischemia–reperfusion (I/R) injury is one of the leading causes of death and disability worldwide. Mitochondrial fission has been shown to be involved in cardiomyocyte death. However, molecular machinery involved in mitochondrial fission during I/R injury has not yet been completely understood. In this study we aimed to investigate molecular mechanisms of controlling activation of dynamin-related protein 1more » (Drp1, a key protein in mitochondrial fission) during anoxia-reoxygenation (A/R) injury of HL1 cardiomyocytes. A/R injury induced cardiomyocyte death accompanied by the increases of mitochondrial fission, reactive oxygen species (ROS) production and activated Drp1 (pSer616 Drp1), and decrease of inactivated Drp1 (pSer637 Drp1) while mitochondrial fusion protein levels were not significantly changed. Blocking Drp1 activity with mitochondrial division inhibitor mdivi1 attenuated cell death, mitochondrial fission, and Drp1 activation after A/R. Trolox, a ROS scavenger, decreased pSer616 Drp1 level and mitochondrial fission after A/R. Immunoprecipitation assay further indicates that cyclin dependent kinase 1 (Cdk1) and protein kinase C isoform delta (PKCδ) bind Drp1, thus increasing mitochondrial fission. Inhibiting Cdk1 and PKCδ attenuated the increases in pSer616 Drp1, mitochondrial fission, and cardiomyocyte death. FK506, a calcineurin inhibitor, blocked the decrease in expression of inactivated pSer637 Drp1 and mitochondrial fission. Our findings reveal the following novel molecular mechanisms controlling mitochondrial fission during A/R injury of cardiomyocytes: (1) ROS are upstream initiators of mitochondrial fission; and (2) the increased mitochondrial fission is resulted from both increased activation and decreased inactivation of Drp1 through Cdk1, PKCδ, and calcineurin-mediated pathways, respectively.« less

Resveratrol, an Nrf2 activator, ameliorates aging-related progressive renal injury

PubMed Central

Kim, Eun Nim; Lim, Ji Hee; Kim, Min Young; Ban, Tae Hyun; Jang, In-Ae; Yoon, Hye Eun; Park, Cheol Whee; Chang, Yoon Sik

2018-01-01

Background. Two important issues in the aging kidney are mitochondrial dysfunction and oxidative stress. An Nrf2 activator, resveratrol, is known to have various effects. Resveratrol may prevent inflammation and oxidative stress by activating Nrf2 and SIRT1 signaling. We examined whether resveratrol could potentially ameliorate the cellular condition, such as renal injury due to cellular oxidative stress and mitochondrial dysfunction caused by aging. Methods. Male 18-month-old C57BL/6 mice were used. Resveratrol (40 mg/kg) was administered to aged mice for 6 months. We compared histological changes, oxidative stress, and aging-related protein expression in the kidney between the resveratrol-treated group (RSV) and the control group (cont). We performed experiments using small-interfering RNAs (siRNAs) for Nrf2 and SIRT1 in cultured HK2 cells. Results. Resveratrol improved renal function, proteinuria, histological changes and inflammation in aging mice. Also, expression of Nrf2-HO-1-NOQ-1 signaling and SIRT1-AMPK-PGC-1α signaling was increased in the RSV group. Transfection with Nrf2 and SIRT1 siRNA prevented resveratrol-induced anti-oxidative effect in HK2 cells in media treated with H2O2. Conclusions. Activation of the Nrf2 and SIRT1 signaling pathways ameliorated oxidative stress and mitochondrial dysfunction. Pharmacological targeting of Nrf2 signaling molecules may reduce the pathologic changes of aging in the kidney. PMID:29326403

Tauroursodeoxycholic acid inhibits endoplasmic reticulum stress, blocks mitochondrial permeability transition pore opening, and suppresses reperfusion injury through GSK-3ß in cardiac H9c2 cells.

PubMed

Xie, Yuxi; He, Yonggui; Cai, Zhiliang; Cai, Jianhang; Xi, Mengyao; Zhang, Yidong; Xi, Jinkun

2016-01-01

This study investigates whether inhibition of endoplasmic reticulum (ER) stress prevents opening of the mitochondrial permeability transition pore (mPTP) and evaluates the corresponding signaling pathways involved in this process. Exposure of cardiac H9c2 cells to 800 µM H 2 O 2 for 20 min opened mPTP in response to oxidative stress, as demonstrated by quenching of tetramethylrhodamine ethyl ester (TMRE) fluorescence. Oxidative stress-induced mPTP opening was rescued by the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) in a dose-dependent manner at low concentrations. The PI3K and PKG inhibitors LY294002 and KT5823 inhibited the effect of TUDCA on mPTP opening, suggesting the involvement of PI3K/Akt and PKG signaling pathways. TUDCA significantly increased glycogen synthase kinase 3 (GSK-3β) phosphorylation at Ser-9, with peak effect at 30 µM TUDCA. The level of GRP78 (ER chaperone) expression was significantly upregulated by 30 µM TUDCA. TUDCA-induced increases in Akt and GSK-3β phosphorylation were inhibited by LY294002, whereas KT5823 suppressed TUDCA-induced increases in VASP and GSK-3β phosphorylation. Oxidative stress severely affected cell morphology and ultrastructure. TUDCA prevented H 2 O 2 -induced ER swelling and mitochondrial damage. TUDCA boosted the viability of cells disrupted by ischemia/reperfusion (I/R), indicating that TUDCA eased reperfusion injury. However, TUDCA did not improve the viability of cells expressing the constitutively active GSK-3β mutant (GSK-3β-S9A-HA) that were subjected to I/R, suggesting an essential role of GSK-3β inactivation in TUDCA-mediated cardioprotection against reperfusion damage. These data indicate that ER stress inhibition prevents mPTP opening and attenuates reperfusion injury through GSK-3β inactivation. The PI3K/Akt and PKG pathways may mediate GSK-3β inactivation.

Rosuvastatin postconditioning protects isolated hearts against ischemia-reperfusion injury: The role of radical oxygen species, PI3K-Akt-GSK-3β pathway, and mitochondrial permeability transition pore.

PubMed

Liu, Chun-Wei; Yang, Fan; Cheng, Shi-Zhao; Liu, Yue; Wan, Liang-Hui; Cong, Hong-Liang

2017-02-01

Glycogen synthase kinase-3β (GSK-3β) and mitochondrial permeability transition pore (mPTP) play an important role in myocardial ischemia-reperfusion injury. The aim of this study was to investigate whether postconditioning with rosuvastatin is able to reduce myocardial ischemia-reperfusion injury and clarify the potential mechanisms. Isolated rat hearts underwent 30 minutes of ischemia and 60 minutes of reperfusion in the presence or absence of rosuvastatin (1-50 nmol/L). The activity of signaling pathway was determined by Western blot analysis, and Ca 2+ -induced mPTP opening was assessed by the use of a potentiometric method. Rosuvastatin significantly reduced myocardial infarct size and improved cardiac function at 5 and 10 nmol/L. Protection disappeared at higher concentration and reverted to increased damage at 50 nmol/L. At 5 nmol/L, rosuvastatin increased the phosphorylation of protein kinase B (Akt) and GSK-3β, concomitant with a higher Ca 2+ load required to open the mPTP. Rosuvastatin postconditioning also significantly increased superoxide dismutase activity and reduced malondialdehyde and radical oxygen species level. LY294002, phosphatidylinositol-3-kinase (PI3K) inhibitors, abolished these protective effects of rosuvastatin postconditioning. Rosuvastatin prevents myocardial ischemia-reperfusion injury by inducing phosphorylation of PI3K-Akt and GSK-3β, preventing oxidative stress and subsequent inhibition of mPTP opening. © 2016 John Wiley & Sons Ltd.

Yap-Hippo pathway regulates cerebral hypoxia-reoxygenation injury in neuroblastoma N2a cells via inhibiting ROCK1/F-actin/mitochondrial fission pathways.

PubMed

Geng, Chizi; Wei, Jianchao; Wu, Chengsi

2018-05-23

Yes-associated protein (Yap), a regulator of cellular apoptosis, has been demonstrated to be involved in cerebral ischemia-reperfusion (IR) injury through poorly defined mechanisms. The present study aimed to explore the role of Yap in regulating cerebral IR injury in vitro, with a focus on mitochondrial fission and ROCK1/F-actin pathways. Our data demonstrated that Yap was actually downregulated in N2a cells after cerebral hypoxia-reoxygenation (HR) injury, and that lower expression of Yap was closely associated with increased cell death. However, the reintroduction of Yap was able to suppress the HR-mediated N2a cells death via blocking the mitochondria-related apoptotic signal. At the molecular levels, Yap overexpression sustained mitochondrial potential, normalized the mitochondrial respiratory function, reduced ROS overproduction, limited HtrA2/Omi release from mitochondria into the nucleus, and suppressed pro-apoptotic proteins activation. Subsequently, functional studies have further illustrated that HR-mediated mitochondrial apoptosis was highly regulated by mitochondrial fission, whereas Yap overexpression was able to attenuate HR-mediated mitochondrial fission and, thus, promote N2a cell survival in the context of HR injury. At last, we demonstrated that Yap handled mitochondrial fission via closing ROCK1/F-actin signaling pathways. Activation of ROCK1/F-actin pathways abrogated the protective role of Yap overexpression on mitochondrial homeostasis and N2a cell survival in the setting of HR injury. Altogether, our data identified Yap as the endogenous defender to relieve HR-mediated nerve damage via antagonizing ROCK1/F-actin/mitochondrial fission pathways.

Ketogenic Diet Improves Brain Ischemic Tolerance and Inhibits NLRP3 Inflammasome Activation by Preventing Drp1-Mediated Mitochondrial Fission and Endoplasmic Reticulum Stress

PubMed Central

Guo, Min; Wang, Xun; Zhao, Yanxin; Yang, Qi; Ding, Hongyan; Dong, Qiang; Chen, Xingdong; Cui, Mei

2018-01-01

Background: Neuroprotective effects of ketogenic diets (KD) have been reported in stroke models, and nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome has also been implicated in the pathogenesis of stroke. This study aimed to investigate the effects of KD on NLRP3 inflammasome and explore the potential molecular mechanisms. Methods: In in vivo study, mice were fed with KD for 3 weeks and then subjected to middle cerebral artery occlusion/reperfusion (MCAO/R)-injury. In in vitro study, SH-SY-5Y cells were treated with β-hydroxybutyrate (BHB) followed by oxygen–glucose deprivation/reoxygenation (OGD/R). NLRP3 inflammasome activation and related regulatory mechanisms were evaluated. Results: Mice fed with KD had increased tolerance to MCAO/R. KD inhibited endoplasmic reticulum (ER) stress and suppressed TXNIP/NLRP3 inflammasome activation in the brain. The in vitro study showed BHB (10 mM) prevented the mitochondrial translocation of dynamin-related protein 1 (Drp1) to inhibit mitochondrial fission. Furthermore, BHB decreased reactive oxygen species (ROS) generation, inhibited ROS-NLRP3 pathway in OGD/R-treated cells, and suppressed ER stress-induced NLRP3 inflammasome activation. Conclusions: KD may suppress ER stress and protect mitochondrial integrity by suppressing the mitochondrial translocation of Drp1 to inhibit NLRP3 inflammasome activation, thus exerting neuroprotective effects. Our findings provide evidence for the potential application of KD in the prevention of ischemic stroke. PMID:29662437

Nitrite therapy after cardiac arrest reduces ROS generation, improves cardiac and neurological function and enhances survival via reversible inhibition of mitochondrial complex I

PubMed Central

Dezfulian, Cameron; Shiva, Sruti; Alekseyenko, Aleksey; Pendyal, Akshay; Beiser, DG; Munasinghe, Jeeva P.; Anderson, Stasia A.; Chesley, Christopher F.; Hoek, TL Vanden; Gladwin, Mark T.

2009-01-01

Background Three-fourths of cardiac arrest survivors die prior to hospital discharge or suffer significant neurological injury. Excepting therapeutic hypothermia and revascularization, no novel therapies have been developed that improve survival or cardiac and neurological function after resuscitation. Nitrite (NO2−) increases cellular resilience to focal ischemia-reperfusion injury in multiple organs. We hypothesized that nitrite therapy may improve outcomes after the unique global ischemia-reperfusion insult of cardiopulmonary arrest. Methods and Results We developed a mouse model of cardiac arrest characterized by 12-minutes of normothermic asystole and a high cardiopulmonary resuscitation (CPR) rate. In this model, global ischemia and CPR was associated with blood and organ nitrite depletion, reversible myocardial dysfunction, impaired alveolar gas exchange, neurological injury and an approximate 50% mortality. A single low dose of intravenous nitrite (50 nmol=1.85 μmol/kg=0.13 mg/kg) compared to blinded saline placebo given at CPR initiation with epinephrine improved cardiac function, survival and neurological outcomes. From a mechanistic standpoint, nitrite treatment restored intracardiac nitrite and increased S-nitrosothiol levels, decreased pathological cardiac mitochondrial oxygen consumption due to reactive oxygen species formation and prevented oxidative enzymatic injury via reversible specific inhibition of respiratory chain complex I. Conclusion Nitrite therapy after resuscitation from 12-minutes of asystole rapidly and reversibly modulated mitochondrial reactive oxygen species generation during early reperfusion, limiting acute cardiac dysfunction and death, as well as neurological impairment in survivors. PMID:19704094

Targeting Mitochondria and Reactive Oxygen Species-Driven Pathogenesis in Diabetic Nephropathy

PubMed Central

Lindblom, Runa; Higgins, Gavin; Coughlan, Melinda; de Haan, Judy B.

2015-01-01

Diabetic kidney disease is one of the major microvascular complications of both type 1 and type 2 diabetes mellitus. Approximately 30% of patients with diabetes experience renal complications. Current clinical therapies can only mitigate the symptoms and delay the progression to end-stage renal disease, but not prevent or reverse it. Oxidative stress is an important player in the pathogenesis of diabetic nephropathy. The activity of reactive oxygen and nitrogen species (ROS/NS), which are by-products of the diabetic milieu, has been found to correlate with pathological changes observed in the diabetic kidney. However, many clinical studies have failed to establish that antioxidant therapy is renoprotective. The discovery that increased ROS/NS activity is linked to mitochondrial dysfunction, endoplasmic reticulum stress, inflammation, cellular senescence, and cell death calls for a refined approach to antioxidant therapy. It is becoming clear that mitochondria play a key role in the generation of ROS/NS and their consequences on the cellular pathways involved in apoptotic cell death in the diabetic kidney. Oxidative stress has also been associated with necrosis via induction of mitochondrial permeability transition. This review highlights the importance of mitochondria in regulating redox balance, modulating cellular responses to oxidative stress, and influencing cell death pathways in diabetic kidney disease. ROS/NS-mediated cellular dysfunction corresponds with progressive disease in the diabetic kidney, and consequently represents an important clinical target. Based on this consideration, this review also examines current therapeutic interventions to prevent ROS/NS-derived injury in the diabetic kidney. These interventions, mainly aimed at reducing or preventing mitochondrial-generated oxidative stress, improving mitochondrial antioxidant defense, and maintaining mitochondrial integrity, may deliver alternative approaches to halt or prevent diabetic kidney disease. PMID:26676666

Mitochondrial reactive oxygen species generation triggers inflammatory response and tissue injury associated with hepatic ischemia-reperfusion: therapeutic potential of mitochondrially-targeted antioxidants

PubMed Central

Mukhopadhyay, Partha; Horváth, Bėla; Zsengellėr, Zsuzsanna; Bátkai, Sándor; Cao, Zongxian; Kechrid, Malek; Holovac, Eileen; Erdėlyi, Katalin; Tanchian, Galin; Liaudet, Lucas; Stillman, Isaac E.; Joseph, Joy; Kalyanaraman, Balaraman; Pacher, Pál

2012-01-01

Mitochondrial reactive oxygen species generation has been implicated in the pathophysiology of ischemia-reperfusion (I/R) injury, however its exact role and its spatial-temporal relationship with inflammation are elusive. Herein we explored the spatial-temporal relationship of oxidative/nitrative stress and inflammatory response during the course of hepatic I/R and the possible therapeutic potential of mitochondrial-targeted antioxidants, using a mouse model of segmental hepatic ischemia-reperfusion injury. Hepatic I/R was characterized by early (at 2 hours of reperfusion) mitochondrial injury, decreased complex I activity, increased oxidant generation in the liver or liver mitochondria, and profound hepatocellular injury/dysfunction with acute pro-inflammatory response (TNF-α, MIP-1αCCL3, MIP-2/CXCL2) without inflammatory cell infiltration, followed by marked neutrophil infiltration and more pronounced secondary wave of oxidative/nitrative stress in the liver (starting from 6 hours of reperfusion and peaking at 24 hours). Mitochondrially-targeted antioxidants, MitoQ or Mito-CP, dose-dependently attenuated I/R-induced liver dysfunction, the early and delayed oxidative and nitrative stress response (HNE/carbonyl adducts, malondialdehyde, 8-OHdG, and 3-nitrotyrosine formation), mitochondrial and histopathological injury/dysfunction, as well as delayed inflammatory cell infiltration and cell death. Mitochondrially generated oxidants play a central role in triggering the deleterious cascade of events associated with hepatic I/R, which may be targeted by novel antioxidants for therapeutic advantage. PMID:22683818

LR-90 prevents methylglyoxal-induced oxidative stress and apoptosis in human endothelial cells

PubMed Central

Figarola, James L.; Singhal, Jyotsana; Rahbar, Samuel; Awasthi, Sanjay

2014-01-01

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis. PMID:24615331

Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model

PubMed Central

Ishida, Tokiko; Kotani, Hirokazu; Miyao, Masashi; Kawai, Chihiro; Jemail, Leila; Abiru, Hitoshi; Tamaki, Keiji

2016-01-01

The pathogenesis of renal impairment in chronic liver diseases (CLDs) has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy), autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet–fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the pathophysiological mechanisms of sublethal tubular cell injury. PMID:26752420

Small Interfering RNA Targeting Mitochondrial Calcium Uniporter Improves Cardiomyocyte Cell Viability in Hypoxia/Reoxygenation Injury by Reducing Calcium Overload.

PubMed

Oropeza-Almazán, Yuriana; Vázquez-Garza, Eduardo; Chapoy-Villanueva, Héctor; Torre-Amione, Guillermo; García-Rivas, Gerardo

2017-01-01

Intracellular Ca 2+ mishandling is an underlying mechanism in hypoxia/reoxygenation (H/R) injury that results in mitochondrial dysfunction and cardiomyocytes death. These events are mediated by mitochondrial Ca 2+ ( m Ca 2+ ) overload that is facilitated by the mitochondrial calcium uniporter (MCU) channel. Along this line, we evaluated the effect of siRNA-targeting MCU in cardiomyocytes subjected to H/R injury. First, cardiomyocytes treated with siRNA demonstrated a reduction of MCU expression by 67%, which resulted in significant decrease in mitochondrial Ca 2+ transport. siRNA treated cardiomyocytes showed decreased mitochondrial permeability pore opening and oxidative stress trigger by Ca 2+ overload. Furthermore, after H/R injury MCU silencing decreased necrosis and apoptosis levels by 30% and 50%, respectively, and resulted in reduction in caspases 3/7, 9, and 8 activity. Our findings are consistent with previous conclusions that demonstrate that MCU activity is partly responsible for cellular injury induced by H/R and support the concept of utilizing siRNA-targeting MCU as a potential therapeutic strategy.

Multifunctional Mitochondrial Epac1 Controls Myocardial Cell Death.

PubMed

Fazal, Loubina; Laudette, Marion; Paula-Gomes, Sílvia; Pons, Sandrine; Conte, Caroline; Tortosa, Florence; Sicard, Pierre; Sainte-Marie, Yannis; Bisserier, Malik; Lairez, Olivier; Lucas, Alexandre; Roy, Jérôme; Ghaleh, Bijan; Fauconnier, Jérémy; Mialet-Perez, Jeanne; Lezoualc'h, Frank

2017-02-17

Although the second messenger cyclic AMP (cAMP) is physiologically beneficial in the heart, it largely contributes to cardiac disease progression when dysregulated. Current evidence suggests that cAMP is produced within mitochondria. However, mitochondrial cAMP signaling and its involvement in cardiac pathophysiology are far from being understood. To investigate the role of MitEpac1 (mitochondrial exchange protein directly activated by cAMP 1) in ischemia/reperfusion injury. We show that Epac1 (exchange protein directly activated by cAMP 1) genetic ablation ( Epac1 -/- ) protects against experimental myocardial ischemia/reperfusion injury with reduced infarct size and cardiomyocyte apoptosis. As observed in vivo, Epac1 inhibition prevents hypoxia/reoxygenation-induced adult cardiomyocyte apoptosis. Interestingly, a deleted form of Epac1 in its mitochondrial-targeting sequence protects against hypoxia/reoxygenation-induced cell death. Mechanistically, Epac1 favors Ca 2+ exchange between the endoplasmic reticulum and the mitochondrion, by increasing interaction with a macromolecular complex composed of the VDAC1 (voltage-dependent anion channel 1), the GRP75 (chaperone glucose-regulated protein 75), and the IP3R1 (inositol-1,4,5-triphosphate receptor 1), leading to mitochondrial Ca 2+ overload and opening of the mitochondrial permeability transition pore. In addition, our findings demonstrate that MitEpac1 inhibits isocitrate dehydrogenase 2 via the mitochondrial recruitment of CaMKII (Ca 2+ /calmodulin-dependent protein kinase II), which decreases nicotinamide adenine dinucleotide phosphate hydrogen synthesis, thereby, reducing the antioxidant capabilities of the cardiomyocyte. Our results reveal the existence, within mitochondria, of different cAMP-Epac1 microdomains that control myocardial cell death. In addition, our findings suggest Epac1 as a promising target for the treatment of ischemia-induced myocardial damage. © 2017 American Heart Association, Inc.

Reversible Disruption of Neuronal Mitochondria by Ischemic and Traumatic Injury Revealed by Quantitative Two-Photon Imaging in the Neocortex of Anesthetized Mice

PubMed Central

Kislin, Mikhail; Sword, Jeremy; Fomitcheva, Ioulia V.; Croom, Deborah; Pryazhnikov, Evgeny; Lihavainen, Eero; Toptunov, Dmytro; Rauvala, Heikki; Ribeiro, Andre S.

2017-01-01

Mitochondria play a variety of functional roles in cortical neurons, from metabolic support and neuroprotection to the release of cytokines that trigger apoptosis. In dendrites, mitochondrial structure is closely linked to their function, and fragmentation (fission) of the normally elongated mitochondria indicates loss of their function under pathological conditions, such as stroke and brain trauma. Using in vivo two-photon microscopy in mouse brain, we quantified mitochondrial fragmentation in a full spectrum of cortical injuries, ranging from severe to mild. Severe global ischemic injury was induced by bilateral common carotid artery occlusion, whereas severe focal stroke injury was induced by Rose Bengal photosensitization. The moderate and mild traumatic injury was inflicted by focal laser lesion and by mild photo-damage, respectively. Dendritic and mitochondrial structural changes were tracked longitudinally using transgenic mice expressing fluorescent proteins localized either in cytosol or in mitochondrial matrix. In response to severe injury, mitochondrial fragmentation developed in parallel with dendritic damage signified by dendritic beading. Reconstruction from serial section electron microscopy confirmed mitochondrial fragmentation. Unlike dendritic beading, fragmentation spread beyond the injury core in focal stroke and focal laser lesion models. In moderate and mild injury, mitochondrial fragmentation was reversible with full recovery of structural integrity after 1–2 weeks. The transient fragmentation observed in the mild photo-damage model was associated with changes in dendritic spine density without any signs of dendritic damage. Our findings indicate that alterations in neuronal mitochondria structure are very sensitive to the tissue damage and can be reversible in ischemic and traumatic injuries. SIGNIFICANCE STATEMENT During ischemic stroke or brain trauma, mitochondria can either protect neurons by supplying ATP and adsorbing excessive Ca2+, or kill neurons by releasing proapoptotic factors. Mitochondrial function is tightly linked to their morphology: healthy mitochondria are thin and long; dysfunctional mitochondria are thick (swollen) and short (fragmented). To date, fragmentation of mitochondria was studied either in dissociated cultured neurons or in brain slices, but not in the intact living brain. Using real-time in vivo two-photon microscopy, we quantified mitochondrial fragmentation during acute pathological conditions that mimic severe, moderate, and mild brain injury. We demonstrated that alterations in neuronal mitochondria structural integrity can be reversible in traumatic and ischemic injuries, highlighting mitochondria as a potential target for therapeutic interventions. PMID:28077713

Protective responses to sublytic complement in the retinal pigment epithelium

PubMed Central

Tan, Li Xuan; Toops, Kimberly A.; Lakkaraju, Aparna

2016-01-01

The retinal pigment epithelium (RPE) is a key site of injury in inherited and age-related macular degenerations. Abnormal activation of the complement system is a feature of these blinding diseases, yet how the RPE combats complement attack is poorly understood. The complement cascade terminates in the cell-surface assembly of membrane attack complexes (MACs), which promote inflammation by causing aberrant signal transduction. Here, we investigated mechanisms crucial for limiting MAC assembly and preserving cellular integrity in the RPE and asked how these are compromised in models of macular degeneration. Using polarized primary RPE and the pigmented Abca4−/− Stargardt disease mouse model, we provide evidence for two protective responses occurring within minutes of complement attack, which are essential for maintaining mitochondrial health in the RPE. First, accelerated recycling of the membrane-bound complement regulator CD59 to the RPE cell surface inhibits MAC formation. Second, fusion of lysosomes with the RPE plasma membrane immediately after complement attack limits sustained elevations in intracellular calcium and prevents mitochondrial injury. Cholesterol accumulation in the RPE, induced by vitamin A dimers or oxidized LDL, inhibits these defense mechanisms by activating acid sphingomyelinase (ASMase), which increases tubulin acetylation and derails organelle traffic. Defective CD59 recycling and lysosome exocytosis after complement attack lead to mitochondrial fragmentation and oxidative stress in the RPE. Drugs that stimulate cholesterol efflux or inhibit ASMase restore both these critical safeguards in the RPE and avert complement-induced mitochondrial injury in vitro and in Abca4−/− mice, indicating that they could be effective therapeutic approaches for macular degenerations. PMID:27432952

Fisetin Confers Cardioprotection against Myocardial Ischemia Reperfusion Injury by Suppressing Mitochondrial Oxidative Stress and Mitochondrial Dysfunction and Inhibiting Glycogen Synthase Kinase 3β Activity.

PubMed

Shanmugam, Karthi; Ravindran, Sriram; Kurian, Gino A; Rajesh, Mohanraj

2018-01-01

Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality worldwide. Timely reperfusion is considered an optimal treatment for AMI. Paradoxically, the procedure of reperfusion can itself cause myocardial tissue injury. Therefore, a strategy to minimize the reperfusion-induced myocardial tissue injury is vital for salvaging the healthy myocardium. Herein, we investigated the cardioprotective effects of fisetin, a natural flavonoid, against ischemia/reperfusion (I/R) injury (IRI) using a Langendorff isolated heart perfusion system. I/R produced significant myocardial tissue injury, which was characterized by elevated levels of lactate dehydrogenase and creatine kinase in the perfusate and decreased indices of hemodynamic parameters. Furthermore, I/R resulted in elevated oxidative stress, uncoupling of the mitochondrial electron transport chain, increased mitochondrial swelling, a decrease of the mitochondrial membrane potential, and induction of apoptosis. Moreover, IRI was associated with a loss of the mitochondrial structure and decreased mitochondrial biogenesis. However, when the animals were pretreated with fisetin, it significantly attenuated the I/R-induced myocardial tissue injury, blunted the oxidative stress, and restored the structure and function of mitochondria. Mechanistically, the fisetin effects were found to be mediated via inhibition of glycogen synthase kinase 3 β (GSK3 β ), which was confirmed by a biochemical assay and molecular docking studies.

Protecting Mitochondrial Bioenergetic Function during Resuscitation from Cardiac Arrest

PubMed Central

Gazmuri, Raúl J.; Radhakrishnan, Jeejabai

2012-01-01

Synopsis Successful resuscitation from cardiac arrest requires reestablishment of aerobic metabolism by reperfusion with oxygenated blood of tissues that have been deprived of oxygen for variables periods of time. However, reperfusion concomitantly activates pathogenic mechanisms known as “reperfusion injury.” At the core of reperfusion injury are mitochondria, playing a critical role as effectors and targets of such injury. Mitochondrial injury compromises oxidative phosphorylation and also prompts release of cytochrome c to the cytosol and bloodstream where it correlates with severity of injury. Main drivers of such injury include Ca2+ overload and oxidative stress. Preclinical work shows that limiting myocardial cytosolic Na+ overload at the time of reperfusion attenuates mitochondrial Ca2+ overload and maintains oxidative phosphorylation yielding functional myocardial benefits that include preservation of left ventricular distensibility. Preservation of left ventricular distensibility enables hemodynamically more effective chest compression. Similar myocardial effect have been reported using erythropoietin hypothesized to protect mitochondrial bioenergetic function presumably through activation of pathways similar to those activated during preconditioning. Incorporation of novel and clinical relevant strategies to protect mitochondrial bioenergetic function are expected to attenuate injury at the time of reperfusion and enhance organ viability ultimately improving resuscitation and survival from cardiac arrest. PMID:22433486

Celastrol from 'Thunder God Vine' protects SH-SY5Y cells through the preservation of mitochondrial function and inhibition of p38 MAPK in a rotenone model of Parkinson's disease.

PubMed

Choi, Bong-Suk; Kim, Hyool; Lee, Hyo Jeong; Sapkota, Kumar; Park, Se Eun; Kim, Seung; Kim, Sung-Jun

2014-01-01

Celastrol, a potent natural triterpene and one of the most promising medicinal molecules, is known to possess a broad range of biological activity. Rotenone, a pesticide and complex I inhibitor, is commonly used to produce experimental models of Parkinson's disease both in vivo and in vitro. The present study was designed to examine the effects of celastrol on cell injury induced by rotenone in the human dopaminergic cells and to elucidate the possible mechanistic clues in its neuroprotective action. We demonstrate that celastrol protects SH-SY5Y cells from rotenone-induced cellular injury and apoptotic cell death. Celastrol also prevented the increased generation of reactive oxygen species and mitochondrial membrane potential (ΔΨm) loss induced by rotenone. Similarly, celastrol treatment inhibited cytochrome c release, Bax/Bcl-2 ratio changes, and caspase-9/3 activation. Celastrol specifically inhibited rotenone-evoked p38 mitogen-activated protein kinase activation in SH-SY5Y cells. These data suggest that celastrol may serve as a potent agent for prevention of neurotoxin-induced neurodegeneration through multiple mechanisms and thus has therapeutic potential for the treatment of neurodegenerative diseases.

Creatine Enhances Mitochondrial-Mediated Oligodendrocyte Survival After Demyelinating Injury

PubMed Central

Nanescu, Sonia E.

2017-01-01

Chronic oligodendrocyte loss, which occurs in the demyelinating disorder multiple sclerosis (MS), contributes to axonal dysfunction and neurodegeneration. Current therapies are able to reduce MS severity, but do not prevent transition into the progressive phase of the disease, which is characterized by chronic neurodegeneration. Therefore, pharmacological compounds that promote oligodendrocyte survival could be beneficial for neuroprotection in MS. Here, we investigated the role of creatine, an organic acid involved in adenosine triphosphate (ATP) buffering, in oligodendrocyte function. We found that creatine increased mitochondrial ATP production directly in oligodendrocyte lineage cell cultures and exerted robust protection on oligodendrocytes by preventing cell death in both naive and lipopolysaccharide-treated mixed glia. Moreover, lysolecithin-mediated demyelination in mice deficient in the creatine-synthesizing enzyme guanidinoacetate-methyltransferase (Gamt) did not affect oligodendrocyte precursor cell recruitment, but resulted in exacerbated apoptosis of regenerated oligodendrocytes in central nervous system (CNS) lesions. Remarkably, creatine administration into Gamt-deficient and wild-type mice with demyelinating injury reduced oligodendrocyte apoptosis, thereby increasing oligodendrocyte density and myelin basic protein staining in CNS lesions. We found that creatine did not affect the recruitment of macrophages/microglia into lesions, suggesting that creatine affects oligodendrocyte survival independently of inflammation. Together, our results demonstrate a novel function for creatine in promoting oligodendrocyte viability during CNS remyelination. SIGNIFICANCE STATEMENT We report that creatine enhances oligodendrocyte mitochondrial function and protects against caspase-dependent oligodendrocyte apoptosis during CNS remyelination. This work has important implications for the development of therapeutic targets for diseases characterized by oligodendrocyte death, including multiple sclerosis. PMID:28069926

Preventive effect of piracetam and vinpocetine on hypoxia-reoxygenation induced injury in primary hippocampal culture.

PubMed

Solanki, P; Prasad, D; Muthuraju, S; Sharma, A K; Singh, S B; Ilavzhagan, G

2011-04-01

The present study investigates the potential of Piracetam and Vinpocetine (nootropic drugs, known to possess neuroprotective properties) in preventing hypoxia-reoxygenation induced oxidative stress in primary hippocampal cell culture. The hippocampal culture was exposed to hypoxia (95% N(2), 5% CO(2)) for 3h and followed by 1h of reoxygenation (21% O(2) and 5% CO(2)) at 37 °C. The primary hippocampal cultures were supplemented with the optimum dose of Piracetam and Vinpocetine, independently, and the cultures were divided into six groups, viz. Control/Normoxia, Hypoxia, Hypoxia+Piracetam, Hypoxia+Vinpocetine, Normoxia + Piracetam and Normoxia+Vinpocetine. The cell-viability assays and biochemical oxidative stress parameters were evaluated for each of the six groups. Administration of 1mM Piracetam or 500 nM Vinpocetine significantly prevents the culture from hypoxia-reoxygenation injury when determined by Neutral Red assay, LDH release and Acetylcholine esterase activity. Results showed that Piracetam and Vinpocetine supplementation significantly prevented the fall of mitochondrial membrane potential, rise in ROS generation and reduction in antioxidant levels associated with the hypoxia-reoxygenation injury. In conclusion, the present study establishes that both Piracetam and Vinpocetine give neuroprotection against hypoxia-reoxygenation injury in primary hippocampal cell culture. Copyright © 2010 Elsevier Ltd. All rights reserved.

Drp1-dependent mitophagy protects against cisplatin-induced apoptosis of renal tubular epithelial cells by improving mitochondrial function

PubMed Central

Qi, Jia; Duan, Suyan; Huang, Zhimin; Zhang, Chengning; Wu, Lin; Zeng, Ming; Zhang, Bo; Wang, Ningning; Mao, Huijuan; Zhang, Aihua; Xing, Changying; Yuan, Yanggang

2017-01-01

Cisplatin chemotherapy often causes acute kidney injury (AKI) in cancer patients. There is increasing evidence that mitochondrial dysfunction plays an important role in cisplatin-induced nephrotoxicity. Degradation of damaged mitochondria is carried out by mitophagy. Although mitophagy is considered of particular importance in protecting against AKI, little is known of the precise role of mitophagy and its molecular mechanisms during cisplatin-induced nephrotoxicity. Also, evidence that activation of mitophagy improved mitochondrial function is lacking. Furthermore, several evidences have shown that mitochondrial fission coordinates with mitophagy. The aim of this study was to investigate whether activation of mitophagy protects against mitochondrial dysfunction and renal proximal tubular cells injury during cisplatin treatment. The effect of mitochondrial fission on mitophagy was also investigated. In cultured human renal proximal tubular cells, we observed that 3-methyladenine, a pharmacological inhibitor of autophagy, blocked mitophagy and exacerbated cisplatin-induced mitochondrial dysfunction and cells injury. In contrast, autophagy activator rapamycin enhanced mitophagy and protected against the harmful effects of cisplatin on mitochondrial function and cells viability. Suppression of mitochondrial fission by knockdown of its main regulator dynamin-related protein-1 (Drp1) decreased cisplatin-induced mitophagy. Meanwhile, Drp1 suppression protected against cisplatin-induced cells injury by inhibiting mitochondrial dysfunction. Our results provide evidence that Drp1-depedent mitophagy has potential as renoprotective targets for the treatment of cisplatin-induced AKI. PMID:28423497

Bmi-1 plays a critical role in protection from renal tubulointerstitial injury by maintaining redox balance

PubMed Central

Jin, Jianliang; Lv, Xianhui; Chen, Lulu; Zhang, Wei; Li, Jinbo; Wang, Qian; Wang, Rong; Lu, Xiang; Miao, Dengshun

2014-01-01

To determine whether Bmi-1 deficiency could lead to renal tubulointerstitial injury by mitochondrial dysfunction and increased oxidative stress in the kidney, 3-week-old Bmi-1-/- mice were treated with the antioxidant N-acetylcysteine (NAC, 1 mg mL−1) in their drinking water, or pyrro-quinoline quinone (PQQ, 4 mg kg−1 diet) in their diet for 2 weeks, and their renal phenotypes were compared with vehicle-treated Bmi1-/- and wild-type mice. Bmi-1 was knocked down in human renal proximal tubular epithelial (HK2) cells which were treated with 1 mm NAC for 72 or 96 h, and their phenotypes were compared with control cells. Five-week-old vehicle-treated Bmi-1-/- mice displayed renal interstitial fibrosis, tubular atrophy, and severe renal function impairment with decreased renal cell proliferation, increased renal cell apoptosis and senescence, and inflammatory cell infiltration. Impaired mitochondrial structure, decreased mitochondrial numbers, and increased oxidative stress occurred in Bmi-1-/- mice; subsequently, this caused DNA damage, the activation of TGF-β1/Smad signaling, and the imbalance between extracellular matrix synthesis and degradation. Oxidative stress-induced epithelial-to-mesenchymal transition of renal tubular epithelial cells was enhanced in Bmi-1 knocked down HK2 cells. All phenotypic alterations caused by Bmi-1 deficiency were ameliorated by antioxidant treatment. These findings indicate that Bmi-1 plays a critical role in protection from renal tubulointerstitial injury by maintaining redox balance and will be a novel therapeutic target for preventing renal tubulointerstitial injury. PMID:24915841

Mpv17 in mitochondria protects podocytes against mitochondrial dysfunction and apoptosis in vivo and in vitro.

PubMed

Casalena, Gabriela; Krick, Stefanie; Daehn, Ilse; Yu, Liping; Ju, Wenjun; Shi, Shaolin; Tsai, Su-yi; D'Agati, Vivette; Lindenmeyer, Maja; Cohen, Clemens D; Schlondorff, Detlef; Bottinger, Erwin P

2014-06-01

Mitochondrial dysfunction is increasingly recognized as contributing to glomerular diseases, including those secondary to mitochondrial DNA (mtDNA) mutations and deletions. Mitochondria maintain cellular redox and energy homeostasis and are a major source of intracellular reactive oxygen species (ROS) production. Mitochondrial ROS accumulation may contribute to stress-induced mitochondrial dysfunction and apoptosis and thereby to glomerulosclerosis. In mice, deletion of the gene encoding Mpv17 is associated with glomerulosclerosis, but the underlying mechanism remains poorly defined. Here we report that Mpv17 localizes to mitochondria of podocytes and its expression is reduced in several glomerular injury models and in human focal segmental glomerulosclerosis (FSGS) but not in minimal change disease. Using models of mild or severe nephrotoxic serum nephritis (NTSN) in Mpv17(+/+) wild-type (WT) and Mpv17(-/-) knockout mice, we found that Mpv17 deficiency resulted in increased proteinuria (mild NTSN) and renal insufficiency (severe NTSN) compared with WT. These lesions were associated with increased mitochondrial ROS generation and mitochondrial injury such as oxidative DNA damage. In vitro, podocytes with loss of Mpv17 function were characterized by increased susceptibility to apoptosis and ROS injury including decreased mitochondrial function, loss of mtDNA content, and change in mitochondrial configuration. In summary, the inner mitochondrial membrane protein Mpv17 in podocytes is essential for the maintenance of mitochondrial homeostasis and protects podocytes against oxidative stress-induced injury both in vitro and in vivo. Copyright © 2014 the American Physiological Society.

Heme oxygenase-1 regulates mitochondrial quality control in the heart

PubMed Central

Hull, Travis D.; Boddu, Ravindra; Guo, Lingling; Tisher, Cornelia C.; Traylor, Amie M.; Patel, Bindiya; Joseph, Reny; Prabhu, Sumanth D.; Suliman, Hagir B.; Piantadosi, Claude A.; George, James F.

2016-01-01

The cardioprotective inducible enzyme heme oxygenase-1 (HO-1) degrades prooxidant heme into equimolar quantities of carbon monoxide, biliverdin, and iron. We hypothesized that HO-1 mediates cardiac protection, at least in part, by regulating mitochondrial quality control. We treated WT and HO-1 transgenic mice with the known mitochondrial toxin, doxorubicin (DOX). Relative to WT mice, mice globally overexpressing human HO-1 were protected from DOX-induced dilated cardiomyopathy, cardiac cytoarchitectural derangement, and infiltration of CD11b+ mononuclear phagocytes. Cardiac-specific overexpression of HO-1 ameliorated DOX-mediated dilation of the sarcoplasmic reticulum as well as mitochondrial disorganization in the form of mitochondrial fragmentation and increased numbers of damaged mitochondria in autophagic vacuoles. HO-1 overexpression promotes mitochondrial biogenesis by upregulating protein expression of NRF1, PGC1α, and TFAM, which was inhibited in WT animals treated with DOX. Concomitantly, HO-1 overexpression inhibited the upregulation of the mitochondrial fission mediator Fis1 and resulted in increased expression of the fusion mediators, Mfn1 and Mfn2. It also prevented dynamic changes in the levels of key mediators of the mitophagy pathway, PINK1 and parkin. Therefore, these findings suggest that HO-1 has a novel role in protecting the heart from oxidative injury by regulating mitochondrial quality control. PMID:27110594

Mitochondrial JNK activation triggers autophagy and apoptosis and aggravates myocardial injury following ischemia/reperfusion.

PubMed

Xu, Jie; Qin, Xinghua; Cai, Xiaoqing; Yang, Lu; Xing, Yuan; Li, Jun; Zhang, Lihua; Tang, Ying; Liu, Jiankang; Zhang, Xing; Gao, Feng

2015-02-01

c-Jun N-terminal kinase (JNK) is a stress-activated mitogen-activated protein kinase that plays a central role in initiating apoptosis in disease conditions. Recent studies have shown that mitochondrial JNK signaling is partly responsible for ischemic myocardial dysfunction; however, the underlying mechanism remains unclear. Here we report for the first time that activation of mitochondrial JNK, rather than JNK localization on mitochondria, induces autophagy and apoptosis and aggravates myocardial ischemia/reperfusion injury. Myocardial ischemia/reperfusion induced a dominant increase of mitochondrial JNK phosphorylation, while JNK mitochondrial localization was reduced. Treatment with Tat-SabKIM1, a retro-inverso peptide which blocks JNK interaction with mitochondria, decreased mitochondrial JNK activation without affecting JNK mitochondrial localization following reperfusion. Tat-SabKIM1 treatment reduced Bcl2-regulated autophagy, cytochrome c-mediated apoptosis and myocardial infarct size. Notably, selective inhibition of mitochondrial JNK activation using Tat-SabKIM1 produced a similar infarct size-reducing effect as inhibiting universal JNK activation with JNK inhibitor SP600125. Moreover, insulin-treated animals exhibited significantly dampened mitochondrial JNK activation accompanied by reduced infarct size and diminished autophagy and apoptosis following reperfusion. Taken together, these findings demonstrate that mitochondrial JNK activation, rather than JNK mitochondrial localization, induces autophagy and apoptosis and exacerbates myocardial ischemia/reperfusion injury. Insulin selectively inhibits mitochondrial JNK activation, contributing to insulin cardioprotection against myocardial ischemic/reperfusion injury. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Oncostatin M (OSM) protects against cardiac ischaemia/reperfusion injury in diabetic mice by regulating apoptosis, mitochondrial biogenesis and insulin sensitivity.

PubMed

Sun, Dongdong; Li, Shuang; Wu, Hao; Zhang, Mingming; Zhang, Xiaotian; Wei, Liping; Qin, Xing; Gao, Erhe

2015-06-01

Oncostatin M (OSM) exhibits many unique biological activities by activating Oβ receptor. However, its role in myocardial I/R injury in diabetic mice remains unknown. The involvement of OSM was assessed in diabetic mice which underwent myocardial I/R injury by OSM treatment or genetic deficiency of OSM receptor Oβ. Its mechanism on cardiomyocyte apoptosis, mitochondrial biogenesis and insulin sensitivity were further studied. OSM alleviated cardiac I/R injury by inhibiting cardiomyocyte apoptosis through inhibition of inositol pyrophosphate 7 (IP7) production, thus activating PI3K/Akt/BAD pathway, decreasing Bax expression while up-regulating Bcl-2 expression and decreasing the ratio of Bax to Bcl-2 in db/db mice. OSM enhanced mitochondrial biogenesis and mitochondrial function in db/db mice subjected to cardiac I/R injury. On the contrary, OSM receptor Oβ knockout exacerbated cardiac I/R injury, increased IP7 production, enhanced cardiomyocyte apoptosis, impaired mitochondrial biogenesis, glucose homoeostasis and insulin sensitivity in cardiac I/R injured diabetic mice. Inhibition of IP7 production by TNP (IP6K inhibitor) exerted similar effects of OSM. The mechanism of OSM on cardiac I/R injury in diabetic mice is partly associated with IP7/Akt and adenine mononucleotide protein kinase/PGC-1α pathway. OSM protects against cardiac I/R Injury by regulating apoptosis, insulin sensitivity and mitochondrial biogenesis in diabetic mice through inhibition of IP7 production. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Lycopene protects human SH-SY5Y neuroblastoma cells against hydrogen peroxide-induced death via inhibition of oxidative stress and mitochondria-associated apoptotic pathways

PubMed Central

FENG, CHUNSHENG; LUO, TIANFEI; ZHANG, SHUYAN; LIU, KAI; ZHANG, YANHONG; LUO, YINAN; GE, PENGFEI

2016-01-01

Oxidative stress, which is characterized by excessive production of reactive oxygen species (ROS), is a common pathway that results in neuronal injury or death due to various types of pathological stress. Although lycopene has been identified as a potent antioxidant, its effect on hydrogen peroxide (H2O2)-induced neuronal damage remains unclear. In the present study, pretreatment with lycopene was observed to protect SH-SY5Y neuroblastoma cells against H2O2-induced death via inhibition of apoptosis resulting from activation of caspase-3 and translocation of apoptosis inducing factor (AIF) to the nucleus. Furthermore, the over-produced ROS, as well as the reduced activities of anti-oxidative enzymes, superoxide dismutase and catalase, were demonstrated to be alleviated by lycopene. Additionally, lycopene counteracted H2O2-induced mitochondrial dysfunction, which was evidenced by suppression of mitochondrial permeability transition pore opening, attenuation of the decline of the mitochondrial membrane potential, and inhibition of the increase of Bax and decrease of Bcl-2 levels within the mitochondria. The release of cytochrome c and AIF from the mitochondria was also reduced. These results indicate that lycopene is a potent neuroprotectant against apoptosis, oxidative stress and mitochondrial dysfunction, and could be administered to prevent neuronal injury or death. PMID:27035331

A mild traumatic brain injury in mice produces lasting deficits in brain metabolism.

PubMed

Lyons, Danielle N; Vekaria, Hemendra; Macheda, Teresa; Bakshi, Vikas; Powell, David K; Gold, Brian T; Lin, Ai-Ling; Sulllivan, Pat; Bachstetter, Adam D

2018-05-29

Metabolic uncoupling has been well-characterized during the first minutes-to-days after a traumatic brain injury (TBI), yet mitochondrial bioenergetics during the weeks-to-months after a brain injury is poorly defined, particularly after a mild TBI. We hypothesized that a closed head injury (CHI) would be associated with deficits in mitochondrial bioenergetics at one month after the injury. A significant decrease in state-III (ATP production) and state-V (complex-I) driven mitochondrial respiration was found at 1-month post-injury in adult C57Bl/6J mice. Isolation of synaptic mitochondria demonstrated that the deficit in state-III and state-V was primarily neuronal. Injured mice had a temporally consistent deficit in memory recall at 1-month post injury. Using proton magnetic resonance spectroscopy (1H MRS) at 7-Tesla, we found significant decreases in phosphocreatine, N-Acetylaspartic acid (NAA), and total choline. We also found regional variations in cerebral blood flow, including both hypo- and hyper- perfusion, as measured by a pseudo-continuous arterial spin labeling MR sequence. Our results highlight a chronic deficit in mitochondrial bioenergetics associated with a CHI that may lead toward a novel approach for neurorestoration following a mild TBI. Magnetic resonance spectroscopy provides a potential biomarker for assessing the efficacy of candidate treatments targeted at improving mitochondrial bioenergetics.

Mitochondrial-targeted DNA repair enzyme 8-oxoguanine DNA glycosylase 1 protects against ventilator-induced lung injury in intact mice.

PubMed

Hashizume, Masahiro; Mouner, Marc; Chouteau, Joshua M; Gorodnya, Olena M; Ruchko, Mykhaylo V; Potter, Barry J; Wilson, Glenn L; Gillespie, Mark N; Parker, James C

2013-02-15

This study tested the hypothesis that oxidative mitochondrial-targeted DNA (mtDNA) damage triggered ventilator-induced lung injury (VILI). Control mice and mice infused with a fusion protein targeting the DNA repair enzyme, 8-oxoguanine-DNA glycosylase 1 (OGG1) to mitochondria were mechanically ventilated with a range of peak inflation pressures (PIP) for specified durations. In minimal VILI (1 h at 40 cmH(2)O PIP), lung total extravascular albumin space increased 2.8-fold even though neither lung wet/dry (W/D) weight ratios nor bronchoalveolar lavage (BAL) macrophage inflammatory protein (MIP)-2 or IL-6 failed to differ from nonventilated or low PIP controls. This increase in albumin space was attenuated by OGG1. Moderately severe VILI (2 h at 40 cmH(2)O PIP) produced a 25-fold increase in total extravascular albumin space, a 60% increase in W/D weight ratio and marked increases in BAL MIP-2 and IL-6, accompanied by oxidative mitochondrial DNA damage, as well as decreases in the total tissue glutathione (GSH) and GSH/GSSH ratio compared with nonventilated lungs. All of these injury indices were attenuated in OGG1-treated mice. At the highest level of VILI (2 h at 50 cmH(2)O PIP), OGG1 failed to protect against massive lung edema and BAL cytokines or against depletion of the tissue GSH pool. Interestingly, whereas untreated mice died before completing the 2-h protocol, OGG1-treated mice lived for the duration of observation. Thus mitochondrially targeted OGG1 prevented VILI over a range of ventilation times and pressures and enhanced survival in the most severely injured group. These findings support the concept that oxidative mtDNA damage caused by high PIP triggers induction of acute lung inflammation and injury.

The compound Chinese medicine "Kang Fu Ling" protects against high power microwave-induced myocardial injury.

PubMed

Zhang, Xueyan; Gao, Yabing; Dong, Ji; Wang, Shuiming; Yao, Binwei; Zhang, Jing; Hu, Shaohua; Xu, Xinping; Zuo, Hongyan; Wang, Lifeng; Zhou, Hongmei; Zhao, Li; Peng, Ruiyun

2014-01-01

The prevention and treatment of Microwave-caused cardiovascular injury remains elusive. This study investigated the cardiovascular protective effects of compound Chinese medicine "Kang Fu Ling" (KFL) against high power microwave (HPM)-induced myocardial injury and the role of the mitochondrial permeability transition pore (mPTP) opening in KFL protection. Male Wistar rats (100) were divided into 5 equal groups: no treatment, radiation only, or radiation followed by treatment with KFL at 0.75, 1.5, or 3 g/kg/day. Electrocardiography was used to Electrophysiological examination. Histological and ultrastructural changes in heart tissue and isolated mitochondria were observed by light microscope and electron microscopy. mPTP opening and mitochondrial membrane potential were detected by confocal laser scanning microscopy and fluorescence analysis. Connexin-43 (Cx-43) and endothelial nitric oxide synthase (eNOS) were detected by immunohistochemistry. The expression of voltage-dependent anion channel (VDAC) was detected by western blotting. At 7 days after radiation, rats without KFL treatment showed a significantly lower heart rate (P<0.01) than untreated controls and a J point shift. Myocyte swelling and rearrangement were evident. Mitochondria exhibited rupture, and decreased fluorescence intensity, suggesting opening of mPTP and a consequent reduction in mitochondrial membrane potential. After treatment with 1.5 g/kg/day KFL for 7 d, the heart rate increased significantly (P<0.01), and the J point shift was reduced flavorfully (P<0.05) compared to untreated, irradiated rats; myocytes and mitochondria were of normal morphology. The fluorescence intensities of dye-treated mitochondria were also increased, suggesting inhibition of mPTP opening and preservation of the mitochondrial membrane potential. The microwave-induced decrease of Cx-43 and VDAC protein expression was significantly reversed. Microwave radiation can cause electrophysiological, histological and ultrastructural changes in the heart. KFL at 1.5 g/kg/day had the greatest protective effect on these cardiovascular events. mPTP plays an important role in the protective effects of KFL against microwave-radiation-induced myocardial injury.

Sirtuin 1 Agonist Minimizes Injury and Improves the Immune Response Following Traumatic Shock.

PubMed

Luciano, Jason A; Kautza, Benjamin; Darwiche, Sophie; Martinez, Silvia; Stratimirovic, Sladjana; Waltz, Paul; Sperry, Jason; Rosengart, Matthew; Shiva, Sruti; Zuckerbraun, Brian S

2015-08-01

Survival from traumatic injury requires a coordinated and controlled inflammatory and immune response. Mitochondrial and metabolic responses to stress have been shown to play a role in these inflammatory and immune responses. We hypothesized that increases in mitochondrial biogenesis via a sirtuin 1 agonist would decrease tissue injury and partially ameliorate the immunosuppression seen following trauma. C57Bl/6 mice were subjected to a multiple trauma model. Mice were pretreated with either 100 mg/kg per day of the sirtuin 1 agonist, Srt1720, via oral gavage for 2 days prior to trauma and extended until the day the animals were killed, or they were pretreated with peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) siRNA via hydrodynamic tail vein injection 48 h prior to trauma. Markers for mitochondrial function and biogenesis were measured in addition to splenocyte proliferative capacity and bacterial clearance. Srt1720 was noted to improve mitochondrial biogenesis, mitochondrial function, and complex IV activity following traumatic injury (P < 0.05), whereas knockdown of PGC1α resulted in exacerbation of mitochondrial dysfunction (P < 0.05). These changes in mitochondrial function were associated with altered severity of hepatic injury with significant reductions in serum alanine aminotransferase levels seen in mice treated with srt1720. Splenocyte proliferative capacity and intraperitoneal bacterial clearance were evaluated as markers for overall immune function following trauma-hemorrhage. Treatment with Srt1720 minimized the trauma-induced decreases in splenocyte proliferation (P < 0.05), whereas treatment with PGC1α siRNA led to diminished bacterial clearance. The PGC1α signaling pathway is an important regulator of mitochondrial function and biogenesis, which can potentially be harnessed to protect against hepatic injury and minimize the immunosuppression that is seen following trauma-hemorrhage.

Melatonin protects cardiac microvasculature against ischemia/reperfusion injury via suppression of mitochondrial fission-VDAC1-HK2-mPTP-mitophagy axis.

PubMed

Zhou, Hao; Zhang, Ying; Hu, Shunying; Shi, Chen; Zhu, Pingjun; Ma, Qiang; Jin, Qinhua; Cao, Feng; Tian, Feng; Chen, Yundai

2017-08-01

The cardiac microvascular system, which is primarily composed of monolayer endothelial cells, is the site of blood supply and nutrient exchange to cardiomyocytes. However, microvascular ischemia/reperfusion injury (IRI) following percutaneous coronary intervention is a woefully neglected topic, and few strategies are available to reverse such pathologies. Here, we studied the effects of melatonin on microcirculation IRI and elucidated the underlying mechanism. Melatonin markedly reduced infarcted area, improved cardiac function, restored blood flow, and lower microcirculation perfusion defects. Histological analysis showed that cardiac microcirculation endothelial cells (CMEC) in melatonin-treated mice had an unbroken endothelial barrier, increased endothelial nitric oxide synthase expression, unobstructed lumen, reduced inflammatory cell infiltration, and less endothelial damage. In contrast, AMP-activated protein kinase α (AMPKα) deficiency abolished the beneficial effects of melatonin on microvasculature. In vitro, IRI activated dynamin-related protein 1 (Drp1)-dependent mitochondrial fission, which subsequently induced voltage-dependent anion channel 1 (VDAC1) oligomerization, hexokinase 2 (HK2) liberation, mitochondrial permeability transition pore (mPTP) opening, PINK1/Parkin upregulation, and ultimately mitophagy-mediated CMEC death. However, melatonin strengthened CMEC survival via activation of AMPKα, followed by p-Drp1 S616 downregulation and p-Drp1 S37 upregulation, which blunted Drp1-dependent mitochondrial fission. Suppression of mitochondrial fission by melatonin recovered VDAC1-HK2 interaction that prevented mPTP opening and PINK1/Parkin activation, eventually blocking mitophagy-mediated cellular death. In summary, this study confirmed that melatonin protects cardiac microvasculature against IRI. The underlying mechanism may be attributed to the inhibitory effects of melatonin on mitochondrial fission-VDAC1-HK2-mPTP-mitophagy axis via activation of AMPKα. © 2017 The Authors. Journal of Pineal Research Published by John Wiley & Sons Ltd.

5-Aminolevulinic acid with sodium ferrous citrate induces autophagy and protects cardiomyocytes from hypoxia-induced cellular injury through MAPK-Nrf-2-HO-1 signaling cascade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Mingyi; Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou; Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha

Background: Hypoxia causes cardiac disease via oxidative stress and mitochondrial dysfunction. 5-Aminolevulinic acid in combination with sodium ferrous citrate (ALA/SFC) has been shown to up-regulate heme oxygenase-1 (HO-1) and decrease macrophage infiltration and renal cell apoptosis in renal ischemia injury mice. However, its underlying mechanism remains largely unknown. The aim of this study was to investigate whether ALA/SFC could protect cardiomyocytes from hypoxia-induced apoptosis by autophagy via HO-1 signaling. Materials & methods: Murine atrial cardiomyocyte HL-1 cells were pretreated with ALA/SFC and then exposed to hypoxia. Results: ALA/SFC pretreatment significantly attenuated hypoxia-induced cardiomyocyte apoptosis, reactive oxygen species production, and mitochondrial injury,more » while it increased cell viability and autophagy levels. HO-1 expression by ALA/SFC was associated with up-regulation and nuclear translocation of Nrf-2, whereas Nrf-2 siRNA dramatically reduced HO-1 expression. ERK1/2, p38, and SAPK/JNK pathways were activated by ALA/SFC and their specific inhibitors significantly reduced ALA/SFC-mediated HO-1 upregulation. Silencing of either Nrf-2 or HO-1and LY294002, inhibitor of autophagy, abolished the protective ability of ALA/AFC against hypoxia-induced injury and reduced ALA/SFC-induced autophagy. Conclusion: Taken together, our data suggest that ALA/SFC induces autophagy via activation of MAPK/Nrf-2/HO-1 signaling pathway to protect cardiomyocytes from hypoxia-induced apoptosis. - Highlights: • ALA/SFC attenuates hypoxia-induced cardiomyocyte apoptosis, reactive oxygen species production, and mitochondrial injury. • ALA/SFC increases the heme oxygenase-1 expression via Nrf-2 and ERK1/2, p38, and SAPK/JNK pathways. • ALA/SFC induces autophagy and inhibition of autophagy prevent ALA/SFC-mediated suppression of hypoxia-induced injury.« less

N-acetyl-cysteine increases cellular dysfunction in progressive chronic kidney damage after acute kidney injury by dampening endogenous antioxidant responses.

PubMed

Small, David M; Sanchez, Washington Y; Roy, Sandrine F; Morais, Christudas; Brooks, Heddwen L; Coombes, Jeff S; Johnson, David W; Gobe, Glenda C

2018-05-01

Oxidative stress and mitochondrial dysfunction exacerbate acute kidney injury (AKI), but their role in any associated progress to chronic kidney disease (CKD) remains unclear. Antioxidant therapies often benefit AKI, but their benefits in CKD are controversial since clinical and preclinical investigations often conflict. Here we examined the influence of the antioxidant N-acetyl-cysteine (NAC) on oxidative stress and mitochondrial function during AKI (20-min bilateral renal ischemia plus reperfusion/IR) and progression to chronic kidney pathologies in mice. NAC (5% in diet) was given to mice 7 days prior and up to 21 days post-IR (21d-IR). NAC treatment resulted in the following: prevented proximal tubular epithelial cell apoptosis at early IR (40-min postischemia), yet enhanced interstitial cell proliferation at 21d-IR; increased transforming growth factor-β1 expression independent of IR time; and significantly dampened nuclear factor-like 2-initiated cytoprotective signaling at early IR. In the long term, NAC enhanced cellular metabolic impairment demonstrated by increased peroxisome proliferator activator-γ serine-112 phosphorylation at 21d-IR. Intravital multiphoton microscopy revealed increased endogenous fluorescence of nicotinamide adenine dinucleotide (NADH) in cortical tubular epithelial cells during ischemia, and at 21d-IR that was not attenuated with NAC. Fluorescence lifetime imaging microscopy demonstrated persistent metabolic impairment by increased free/bound NADH in the cortex at 21d-IR that was enhanced by NAC. Increased mitochondrial dysfunction in remnant tubular cells was demonstrated at 21d-IR by tetramethylrhodamine methyl ester fluorimetry. In summary, NAC enhanced progression to CKD following AKI not only by dampening endogenous cellular antioxidant responses at time of injury but also by enhancing persistent kidney mitochondrial and metabolic dysfunction.

The role of hexokinase in cardioprotection – mechanism and potential for translation

PubMed Central

Pereira, Gonçalo C; Pasdois, Philippe

2015-01-01

Mitochondrial permeability transition pore (mPTP) opening plays a critical role in cardiac reperfusion injury and its prevention is cardioprotective. Tumour cell mitochondria usually have high levels of hexokinase isoform 2 (HK2) bound to their outer mitochondrial membranes (OMM) and HK2 binding to heart mitochondria has also been implicated in resistance to reperfusion injury. HK2 dissociates from heart mitochondria during ischaemia, and the extent of this correlates with the infarct size on reperfusion. Here we review the mechanisms and regulations of HK2 binding to mitochondria and how this inhibits mPTP opening and consequent reperfusion injury. Major determinants of HK2 dissociation are the elevated glucose‐6‐phosphate concentrations and decreased pH in ischaemia. These are modulated by the myriad of signalling pathways implicated in preconditioning protocols as a result of a decrease in pre‐ischaemic glycogen content. Loss of mitochondrial HK2 during ischaemia is associated with permeabilization of the OMM to cytochrome c, which leads to greater reactive oxygen species production and mPTP opening during reperfusion. Potential interactions between HK2 and OMM proteins associated with mitochondrial fission (e.g. Drp1) and apoptosis (B‐cell lymphoma 2 family members) in these processes are examined. Also considered is the role of HK2 binding in stabilizing contact sites between the OMM and the inner membrane. Breakage of these during ischaemia is proposed to facilitate cytochrome c loss during ischaemia while increasing mPTP opening and compromising cellular bioenergetics during reperfusion. We end by highlighting the many unanswered questions and discussing the potential of modulating mitochondrial HK2 binding as a pharmacological target. Linked Articles This article is part of a themed section on Conditioning the Heart – Pathways to Translation. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue‐8 PMID:25204670

Ebselen protects mitochondrial function and oxidative stress while inhibiting the mitochondrial apoptosis pathway after acute spinal cord injury.

PubMed

Jia, Zhi-Qiang; Li, San-Qiang; Qiao, Wei-Qiang; Xu, Wen-Zhong; Xing, Jian-Wu; Liu, Jian-Tao; Song, Hui; Gao, Zhong-Yang; Xing, Bing-Wen; He, Xi-Jing

2018-05-04

Ebselen is a fat-soluble small molecule and organic selenium compound that regulates the activity of glutathione peroxidase to alleviate mitochondrial oxidative stress and improve mitochondrial function. In the present study, we aimed to investigate the effects of ebselen on mitochondrial oxidative stress response, mitochondrial apotosis, and motor behaviors after spinal cord injury (SCI). We found that ebselen significantly increased the BBB score in motor behavior, thus suggesting a rescue effect of ebselen on motor function after SCI in rats. Meanwhile, we revealed that ebselen can increase glutathione (GSH) content as well as superoxide dismutase (SOD) and catalase (CAT) activities after SCI-this suggests ebselen has an antioxidant effect. Furthermore, the ATP content and Na + -K + -ATPase activity in mitochondria were increased by ebselen after SCI, while the mitochondrial membrane potential (MMP) was decreased by ebselen. The Cytochrome C and Smac release from mitochondria were reduced by ebselen after SCI, thus indicating improved membrane permeability by ebselen. Moreover, the alterations in caspase-3, Bax and Bcl-2 protein expression, as well as the proportion of cell apoptosis were improved by ebselen treatment, which together suggested that ebselen has an inhibitory effect on mitochondrial apotosis pathways after SCI. Taken together, our results suggest that ebselen can inhibit secondary damage caused by spinal cord injury. Indeed it plays a neuroprotective role in spinal cord injury perhaps by improving mitochondrial function and inhibiting the mitochondrial apoptosis pathway. Copyright © 2018 Elsevier B.V. All rights reserved.

A Topical Mitochondria-Targeted Redox Cycling Nitroxide Mitigates Oxidative Stress Induced Skin Damage

PubMed Central

Brand, Rhonda M.; Epperly, Michael W.; Stottlemyer, J. Mark; Skoda, Erin M.; Gao, Xiang; Li, Song; Huq, Saiful; Wipf, Peter; Kagan, Valerian E.; Greenberger, Joel S.; Falo, Louis D.

2017-01-01

Skin is the largest human organ and provides a first line of defense that includes physical, chemical, and immune mechanisms to combat environmental stress. Radiation is a prevalent environmental stressor. Radiation induced skin damage ranges from photoaging and cutaneous carcinogenesis from UV exposure, to treatment-limiting radiation dermatitis associated with radiotherapy, to cutaneous radiation syndrome, a frequently fatal consequence of exposures from nuclear accidents. The major mechanism of skin injury common to these exposures is radiation induced oxidative stress. Efforts to prevent or mitigate radiation damage have included development of antioxidants capable of reducing reactive oxygen species (ROS). Mitochondria are particularly susceptible to oxidative stress, and mitochondrial dependent apoptosis plays a major role in radiation induced tissue damage. We reasoned that targeting a redox cycling nitroxide to mitochondria could prevent ROS accumulation, limiting downstream oxidative damage and preserving mitochondrial function. Here we show that in both mouse and human skin, topical application of a mitochondrial targeted antioxidant prevents and mitigates radiation induced skin damage characterized by clinical dermatitis, loss of barrier function, inflammation, and fibrosis. Further, damage mitigation is associated with reduced apoptosis, preservation of the skin’s antioxidant capacity, and reduction of irreversible DNA and protein oxidation associated with oxidative stress. PMID:27794421

Mitofusin-2 protects against cold stress-induced cell injury in HEK293 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wenbin; Chen, Yaomin; Yang, Qun

2010-06-25

Mitochondrial impairment is hypothesized to contribute to cell injury during cold stress. Mitochondria fission and fusion are closely related in the function of the mitochondria, but the precise mechanisms whereby these processes regulate cell injury during cold stress remain to be determined. HEK293 cells were cultured in a cold environment (4.0 {+-} 0.1 {sup o}C) for 2, 4, 8, or 12 h. Western blot analyses showed that these cells expressed decreased fission-related protein Drp1 and increased fusion-related protein Mfn2 at 4 h; meanwhile, electron microscopy analysis revealed large and long mitochondrial morphology within these cells, indicating increased mitochondrial fusion. Withmore » silencing of Mfn2 but not of Mfn1 by siRNA promoted cold-stress-induced cell death with decreased ATP production in HEK293 cells. Our results show that increased expression of Mfn2 and mitochondrial fusion are important for mitochondrial function as well as cell survival during cold stress. These findings have important implications for understanding the mechanisms of mitochondrial fusion and fission in cold-stress-induced cell injury.« less

The protective effect of lipid emulsion in preventing bupivacaine-induced mitochondrial injury and apoptosis of H9C2 cardiomyocytes.

PubMed

Chen, Zhe; Jin, Zhousheng; Xia, Yun; Zhao, Shishi; Xu, Xuzhong; Papadimos, Thomas J; Wang, Quanguang

2017-11-01

Lipid emulsion (LE) has been shown to be effective in the resuscitation of bupivacaine-induced cardiac arrest, but the precise mechanism of this action has not been fully elucidated. Pursuant to this lack of information on the mechanism in which LE protects the myocardium during bupivacaine-induced toxicity, we explored mitochondrial function and cell apoptosis. H9C2 cardiomyocytes were used in study. Cells were randomly divided in different groups and were cultivated 6 h, 12 h, and 24 h. The mitochondria were extracted and mitochondrial ATP content was measured, as was mitochondrial membrane potential, the concentration of calcium ion (Ca2+), and the activity of Ca2+-ATP enzyme (Ca2+-ATPase). Cells from groups Bup1000, LE group, and Bup1000LE were collected to determine cell viability, cell apoptosis, and electron microscopy scanning of mitochondrial ultrastructure (after 24 h). We found that LE can reverse the inhibition of the mitochondrial function induced by bupivacaine, regulate the concentration of calcium ion in mitochondria, resulting in the protection of myocardial cells from toxicity induced by bupivacaine.

Protective effects of dietary avocado oil on impaired electron transport chain function and exacerbated oxidative stress in liver mitochondria from diabetic rats.

PubMed

Ortiz-Avila, Omar; Gallegos-Corona, Marco Alonso; Sánchez-Briones, Luis Alberto; Calderón-Cortés, Elizabeth; Montoya-Pérez, Rocío; Rodriguez-Orozco, Alain R; Campos-García, Jesús; Saavedra-Molina, Alfredo; Mejía-Zepeda, Ricardo; Cortés-Rojo, Christian

2015-08-01

Electron transport chain (ETC) dysfunction, excessive ROS generation and lipid peroxidation are hallmarks of mitochondrial injury in the diabetic liver, with these alterations also playing a role in the development of non-alcoholic fatty liver disease (NAFLD). Enhanced mitochondrial sensitivity to lipid peroxidation during diabetes has been also associated to augmented content of C22:6 in membrane phospholipids. Thus, we aimed to test whether avocado oil, a rich source of C18:1 and antioxidants, attenuates the deleterious effects of diabetes on oxidative status of liver mitochondria by decreasing unsaturation of acyl chains of membrane lipids and/or by improving ETC functionality and decreasing ROS generation. Streptozocin-induced diabetes elicited a noticeable increase in the content of C22:6, leading to augmented mitochondrial peroxidizability index and higher levels of lipid peroxidation. Mitochondrial respiration and complex I activity were impaired in diabetic rats with a concomitant increase in ROS generation using a complex I substrate. This was associated to a more oxidized state of glutathione, All these alterations were prevented by avocado oil except by the changes in mitochondrial fatty acid composition. Avocado oil did not prevented hyperglycemia and polyphagia although did normalized hyperlipidemia. Neither diabetes nor avocado oil induced steatosis. These results suggest that avocado oil improves mitochondrial ETC function by attenuating the deleterious effects of oxidative stress in the liver of diabetic rats independently of a hypoglycemic effect or by modifying the fatty acid composition of mitochondrial membranes. These findings might have also significant implications in the progression of NAFLD in experimental models of steatosis.

Mdivi-1 ameliorates early brain injury after subarachnoid hemorrhage via the suppression of inflammation-related blood-brain barrier disruption and endoplasmic reticulum stress-based apoptosis.

PubMed

Fan, Lin-Feng; He, Ping-You; Peng, Yu-Cong; Du, Qing-Hua; Ma, Yi-Jun; Jin, Jian-Xiang; Xu, Hang-Zhe; Li, Jian-Ru; Wang, Zhi-Jiang; Cao, Sheng-Long; Li, Tao; Yan, Feng; Gu, Chi; Wang, Lin; Chen, Gao

2017-11-01

Aberrant modulation of mitochondrial dynamic network, which shifts the balance of fusion and fission towards fission, is involved in brain damage of various neurodegenerative diseases including Parkinson's disease, Huntington's disease and Alzheimer's disease. A recent research has shown that the inhibition of mitochondrial fission alleviates early brain injury after experimental subarachnoid hemorrhage, however, the underlying molecular mechanisms have remained to be elucidated. This study was undertaken to characterize the effects of the inhibition of dynamin-related protein-1 (Drp1, a dominator of mitochondrial fission) on blood-brain barrier (BBB) disruption and neuronal apoptosis following SAH and the potential mechanisms. The endovascular perforation model of SAH was performed in adult male Sprague Dawley rats. The results indicated Mdivi-1(a selective Drp1 inhibitor) reversed the morphologic changes of mitochondria and Drp1 translocation, reduced ROS levels, ameliorated the BBB disruption and brain edema remarkably, decreased the expression of MMP-9 and prevented degradation of tight junction proteins-occludin, claudin-5 and ZO-1. Mdivi-1 administration also inhibited the nuclear translocation of nuclear factor-kappa B (NF-κB), leading to decreased expressions of TNF-ɑ, IL-6 and IL-1ß. Moreover, Mdivi-1 treatment attenuated neuronal cell death and improved neurological outcome. To investigate the underlying mechanisms further, we determined that Mdivi-1 reduced p-PERK, p-eIF2α, CHOP, cleaved caspase-3 and Bax expression as well as increased Bcl-2 expression. Rotenone (a selective inhibitor of mitochondrial complexes I) abolished both the anti-BBB disruption and anti-apoptosis effects of Mdivi-1. In conclusion, these data implied that excessive mitochondrial fission might inhibit mitochondrial complex I to become a cause of oxidative stress in SAH, and the inhibition of Drp1 by Mdivi-1 attenuated early brain injury after SAH probably via the suppression of inflammation-related blood-brain barrier disruption and endoplasmic reticulum stress-based apoptosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Rat liver mitochondrial damage under acute or chronic carbon tetrachloride-induced intoxication: Protection by melatonin and cranberry flavonoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheshchevik, V.T.; Department of Biochemistry, Yanka Kupala Grodno State University, Len. Kom. Blvd. - 50, 230017 Grodno; Lapshina, E.A.

In current societies, the risk of toxic liver damage has markedly increased. The aim of the present work was to carry out further research into the mechanism(s) of liver mitochondrial damage induced by acute (0.8 g/kg body weight, single injection) or chronic (1.6 g/ kg body weight, 30 days, biweekly injections) carbon tetrachloride – induced intoxication and to evaluate the hepatoprotective potential of the antioxidant, melatonin, as well as succinate and cranberry flavonoids in rats. Acute intoxication resulted in considerable impairment of mitochondrial respiratory parameters in the liver. The activity of mitochondrial succinate dehydrogenase (complex II) decreased (by 25%, pmore » < 0.05). Short-term melatonin treatment (10 mg/kg, three times) of rats did not reduce the degree of toxic mitochondrial dysfunction but decreased the enhanced NO production. After 30-day chronic intoxication, no significant change in the respiratory activity of liver mitochondria was observed, despite marked changes in the redox-balance of mitochondria. The activities of the mitochondrial enzymes, succinate dehydrogenase and glutathione peroxidase, as well as that of cytoplasmic catalase in liver cells were inhibited significantly. Mitochondria isolated from the livers of the rats chronically treated with CCl{sub 4} displayed obvious irreversible impairments. Long-term melatonin administration (10 mg/kg, 30 days, daily) to chronically intoxicated rats diminished the toxic effects of CCl{sub 4}, reducing elevated plasma activities of alanine aminotransferase and aspartate aminotransferase and bilirubin concentration, prevented accumulation of membrane lipid peroxidation products in rat liver and resulted in apparent preservation of the mitochondrial ultrastructure. The treatment of the animals by the complex of melatonin (10 mg/kg) plus succinate (50 mg/kg) plus cranberry flavonoids (7 mg/kg) was even more effective in prevention of toxic liver injury and liver mitochondria damage. Highlights: ► After 30-day chronic CCl{sub 4} intoxication mitochondria displayed considerable changes. ► The functional parameters of mitochondria were similar to the control values. ► Melatonin + succinate + flavonoids prevented mitochondrial ultrastructure damage. ► The above complex enhanced regenerative processes in the liver.« less

Creatine Enhances Mitochondrial-Mediated Oligodendrocyte Survival After Demyelinating Injury.

PubMed

Chamberlain, Kelly A; Chapey, Kristen S; Nanescu, Sonia E; Huang, Jeffrey K

2017-02-08

Chronic oligodendrocyte loss, which occurs in the demyelinating disorder multiple sclerosis (MS), contributes to axonal dysfunction and neurodegeneration. Current therapies are able to reduce MS severity, but do not prevent transition into the progressive phase of the disease, which is characterized by chronic neurodegeneration. Therefore, pharmacological compounds that promote oligodendrocyte survival could be beneficial for neuroprotection in MS. Here, we investigated the role of creatine, an organic acid involved in adenosine triphosphate (ATP) buffering, in oligodendrocyte function. We found that creatine increased mitochondrial ATP production directly in oligodendrocyte lineage cell cultures and exerted robust protection on oligodendrocytes by preventing cell death in both naive and lipopolysaccharide-treated mixed glia. Moreover, lysolecithin-mediated demyelination in mice deficient in the creatine-synthesizing enzyme guanidinoacetate-methyltransferase ( Gamt ) did not affect oligodendrocyte precursor cell recruitment, but resulted in exacerbated apoptosis of regenerated oligodendrocytes in central nervous system (CNS) lesions. Remarkably, creatine administration into Gamt -deficient and wild-type mice with demyelinating injury reduced oligodendrocyte apoptosis, thereby increasing oligodendrocyte density and myelin basic protein staining in CNS lesions. We found that creatine did not affect the recruitment of macrophages/microglia into lesions, suggesting that creatine affects oligodendrocyte survival independently of inflammation. Together, our results demonstrate a novel function for creatine in promoting oligodendrocyte viability during CNS remyelination. SIGNIFICANCE STATEMENT We report that creatine enhances oligodendrocyte mitochondrial function and protects against caspase-dependent oligodendrocyte apoptosis during CNS remyelination. This work has important implications for the development of therapeutic targets for diseases characterized by oligodendrocyte death, including multiple sclerosis. Copyright © 2017 Chamberlain et al.

Erythropoietin Employs Cell Longevity Pathways of SIRT1 to Foster Endothelial Vascular Integrity During Oxidant Stress

PubMed Central

Hou, Jinling; Wang, Shaohui; Shang, Yan Chen; Chong, Zhao Zhong; Maiese, Kenneth

2011-01-01

Given the cytoprotective ability of erythropoietin (EPO) in cerebral microvascular endothelial cells (ECs) and the invaluable role of ECs in the central nervous system, it is imperative to elucidate the cellular pathways for EPO to protect ECs against brain injury. Here we illustrate that EPO relies upon the modulation of SIRT1 (silent mating type information regulator 2 homolog 1) in cerebral microvascular ECs to foster cytoprotection during oxygen-glucose deprivation (OGD). SIRT1 activation which results in the inhibition of apoptotic early membrane phosphatidylserine (PS) externalization and subsequent DNA degradation during OGD becomes a necessary component for EPO protection in ECs, since inhibition of SIRT1 activity or diminishing its expression by gene silencing abrogates cell survival supported by EPO during OGD. Furthermore, EPO promotes the subcellular trafficking of SIRT1 to the nucleus which is necessary for EPO to foster vascular protection. EPO through SIRT1 averts apoptosis through activation of protein kinase B (Akt1) and the phosphorylation and cytoplasmic retention of the forkhead transcription factor FoxO3a. SIRT1 through EPO activation also utilizes mitochondrial pathways to prevent mitochondrial depolarization, cytochrome c release, and Bad, caspase 1, and caspase 3 activation. Our work identifies novel pathways for EPO in the vascular system that can govern the activity of SIRT1 to prevent apoptotic injury through Akt1, FoxO3a phosphorylation and trafficking, mitochondrial membrane permeability, Bad activation, and caspase 1 and 3 activities in ECs during oxidant stress. PMID:21722091

Diabetes and Kidney Disease: Role of Oxidative Stress

PubMed Central

Jha, Jay C.; Banal, Claudine; Chow, Bryna S.M.; Cooper, Mark E.

2016-01-01

Abstract Significance: Intrarenal oxidative stress plays a critical role in the initiation and progression of diabetic kidney disease (DKD). Enhanced oxidative stress results from overproduction of reactive oxygen species (ROS) in the context of concomitant, insufficient antioxidant pathways. Renal ROS production in diabetes is predominantly mediated by various NADPH oxidases (NOXs), but a defective antioxidant system as well as mitochondrial dysfunction may also contribute. Recent Advances: Effective agents targeting the source of ROS generation hold the promise to rescue the kidney from oxidative damage and prevent subsequent progression of DKD. Critical Issues and Future Directions: In the present review, we summarize and critically analyze molecular and cellular mechanisms that have been demonstrated to be involved in NOX-induced renal injury in diabetes, with particular focus on the role of increased glomerular injury, the development of albuminuria, and tubulointerstitial fibrosis, as well as mitochondrial dysfunction. Furthermore, novel agents targeting NOX isoforms are discussed. Antioxid. Redox Signal. 25, 657–684. PMID:26906673

Adrenergic Signaling Regulates Mitochondrial Ca2+ Uptake Through Pyk2-Dependent Tyrosine Phosphorylation of the Mitochondrial Ca2+ Uniporter

PubMed Central

Jhun, Bong Sook; Xu, Shangcheng; Hurst, Stephen; Raffaello, Anna; Liu, Xiaoyun; Yi, Bing; Zhang, Huiliang; Gross, Polina; Mishra, Jyotsna; Ainbinder, Alina; Kettlewell, Sarah; Smith, Godfrey L.; Dirksen, Robert T.; Wang, Wang; Rizzuto, Rosario

2014-01-01

Abstract Aims: Mitochondrial Ca2+ homeostasis is crucial for balancing cell survival and death. The recent discovery of the molecular identity of the mitochondrial Ca2+ uniporter pore (MCU) opens new possibilities for applying genetic approaches to study mitochondrial Ca2+ regulation in various cell types, including cardiac myocytes. Basal tyrosine phosphorylation of MCU was reported from mass spectroscopy of human and mouse tissues, but the signaling pathways that regulate mitochondrial Ca2+ entry through posttranslational modifications of MCU are completely unknown. Therefore, we investigated α1-adrenergic-mediated signal transduction of MCU posttranslational modification and function in cardiac cells. Results: α1-adrenoceptor (α1-AR) signaling translocated activated proline-rich tyrosine kinase 2 (Pyk2) from the cytosol to mitochondrial matrix and accelerates mitochondrial Ca2+ uptake via Pyk2-dependent MCU phosphorylation and tetrametric MCU channel pore formation. Moreover, we found that α1-AR stimulation increases reactive oxygen species production at mitochondria, mitochondrial permeability transition pore activity, and initiates apoptotic signaling via Pyk2-dependent MCU activation and mitochondrial Ca2+ overload. Innovation: Our data indicate that inhibition of α1-AR-Pyk2-MCU signaling represents a potential novel therapeutic target to limit or prevent mitochondrial Ca2+ overload, oxidative stress, mitochondrial injury, and myocardial death during pathophysiological conditions, where chronic adrenergic stimulation is present. Conclusion: The α1-AR-Pyk2-dependent tyrosine phosphorylation of the MCU regulates mitochondrial Ca2+ entry and apoptosis in cardiac cells. Antioxid. Redox Signal. 21, 863–879. PMID:24800979

Fibroblast growth factor 2 protects against renal ischaemia/reperfusion injury by attenuating mitochondrial damage and proinflammatory signalling.

PubMed

Tan, Xiao-Hua; Zheng, Xiao-Meng; Yu, Li-Xia; He, Jian; Zhu, Hong-Mei; Ge, Xiu-Ping; Ren, Xiao-Li; Ye, Fa-Qing; Bellusci, Saverio; Xiao, Jian; Li, Xiao-Kun; Zhang, Jin-San

2017-11-01

Ischaemia-reperfusion injury (I/RI) is a common cause of acute kidney injury (AKI). The molecular basis underlying I/RI-induced renal pathogenesis and measures to prevent or reverse this pathologic process remains to be resolved. Basic fibroblast growth factor (FGF2) is reported to have protective roles of myocardial infarction as well as in several other I/R related disorders. Herein we present evidence that FGF2 exhibits robust protective effect against renal histological and functional damages in a rat I/RI model. FGF2 treatment greatly alleviated I/R-induced acute renal dysfunction and largely blunted I/R-induced elevation in serum creatinine and blood urea nitrogen, and also the number of TUNEL-positive tubular cells in the kidney. Mechanistically, FGF2 substantially ameliorated renal I/RI by mitigating several mitochondria damaging parameters including pro-apoptotic alteration of Bcl2/Bax expression, caspase-3 activation, loss of mitochondrial membrane potential and K ATP channel integrity. Of note, the protective effect of FGF2 was significantly compromised by the K ATP channel blocker 5-HD. Interestingly, I/RI alone resulted in mild activation of FGFR, whereas FGF2 treatment led to more robust receptor activation. More significantly, post-I/RI administration of FGF2 also exhibited robust protection against I/RI by reducing cell apoptosis, inhibiting the release of damage-associated molecular pattern molecule HMBG1 and activation of its downstream inflammatory cytokines such as IL-1α, IL-6 and TNF α. Taken together, our data suggest that FGF2 offers effective protection against I/RI and improves animal survival by attenuating mitochondrial damage and HMGB1-mediated inflammatory response. Therefore, FGF2 has the potential to be used for the prevention and treatment of I/RI-induced AKI. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Pretreatment with Sodium Phenylbutyrate Alleviates Cerebral Ischemia/Reperfusion Injury by Upregulating DJ-1 Protein.

PubMed

Yang, Rui-Xin; Lei, Jie; Wang, Bo-Dong; Feng, Da-Yun; Huang, Lu; Li, Yu-Qian; Li, Tao; Zhu, Gang; Li, Chen; Lu, Fang-Fang; Nie, Tie-Jian; Gao, Guo-Dong; Gao, Li

2017-01-01

Oxidative stress and mitochondrial dysfunction play critical roles in ischemia/reperfusion (I/R) injury. DJ-1 is an endogenous antioxidant that attenuates oxidative stress and maintains mitochondrial function, likely acting as a protector of I/R injury. In the present study, we explored the protective effect of a possible DJ-1 agonist, sodium phenylbutyrate (SPB), against I/R injury by protecting mitochondrial dysfunction via the upregulation of DJ-1 protein. Pretreatment with SPB upregulated the DJ-1 protein level and rescued the I/R injury-induced DJ-1 decrease about 50% both in vivo and in vitro . SPB also improved cellular viability and mitochondrial function and alleviated neuronal apoptosis both in cell and animal models; these effects of SPB were abolished by DJ-1 knockdown with siRNA. Furthermore, SPB improved the survival rate about 20% and neurological functions, as well as reduced about 50% of the infarct volume and brain edema, of middle cerebral artery occlusion mice 23 h after reperfusion. Therefore, our findings demonstrate that preconditioning of SPB possesses a neuroprotective effect against cerebral I/R injury by protecting mitochondrial function dependent on the DJ-1 upregulation, suggesting that DJ-1 is a potential therapeutic target for clinical ischemic stroke.

Pretreatment with Sodium Phenylbutyrate Alleviates Cerebral Ischemia/Reperfusion Injury by Upregulating DJ-1 Protein

PubMed Central

Yang, Rui-Xin; Lei, Jie; Wang, Bo-Dong; Feng, Da-Yun; Huang, Lu; Li, Yu-Qian; Li, Tao; Zhu, Gang; Li, Chen; Lu, Fang-Fang; Nie, Tie-Jian; Gao, Guo-Dong; Gao, Li

2017-01-01

Oxidative stress and mitochondrial dysfunction play critical roles in ischemia/reperfusion (I/R) injury. DJ-1 is an endogenous antioxidant that attenuates oxidative stress and maintains mitochondrial function, likely acting as a protector of I/R injury. In the present study, we explored the protective effect of a possible DJ-1 agonist, sodium phenylbutyrate (SPB), against I/R injury by protecting mitochondrial dysfunction via the upregulation of DJ-1 protein. Pretreatment with SPB upregulated the DJ-1 protein level and rescued the I/R injury-induced DJ-1 decrease about 50% both in vivo and in vitro. SPB also improved cellular viability and mitochondrial function and alleviated neuronal apoptosis both in cell and animal models; these effects of SPB were abolished by DJ-1 knockdown with siRNA. Furthermore, SPB improved the survival rate about 20% and neurological functions, as well as reduced about 50% of the infarct volume and brain edema, of middle cerebral artery occlusion mice 23 h after reperfusion. Therefore, our findings demonstrate that preconditioning of SPB possesses a neuroprotective effect against cerebral I/R injury by protecting mitochondrial function dependent on the DJ-1 upregulation, suggesting that DJ-1 is a potential therapeutic target for clinical ischemic stroke. PMID:28649223

Osthole attenuates spinal cord ischemia-reperfusion injury through mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction in rats.

PubMed

Zhou, Yue-fei; Li, Liang; Feng, Feng; Yuan, Hua; Gao, Da-kuan; Fu, Luo-an; Fei, Zhou

2013-12-01

Osthole, the main bioactive compounds isolated from the traditional Chinese medical herb broad Cnidium monnieri (L.) cusson, has been shown to exert spectrum of pharmacologic activities. The aim of this study was to investigate the potential neuroprotective effects of osthole against spinal cord ischemia-reperfusion injury in rats. Osthole was administrated at the concentration of 0.1, 1, 10, 50, or 200 mg/kg (intraperitoneally) 1 h before spinal cord ischemia. The effects on spinal cord injury were measured by spinal cord water content, infarct volume, hematoxylin and eosin staining, and neurologic assessment. Mitochondria were purified from injured spinal cord tissue to determine mitochondrial function. We found that treatment with osthole (10 and 50 mg/kg) significantly decreased spinal cord water content and infarct volume, preserved normal motor neurons, and improved neurologic functions. These protective effects can be also observed even if the treatment was delayed to 4 h after reperfusion. Osthole treatment preserved mitochondrial membrane potential level, reduced reactive oxygen species production, increased adenosine triphosphate generation, and inhibited cytochrome c release in mitochondrial samples. Moreover, osthole increased mitochondria respiratory chain complex activities in spinal cord tissue, with no effect on mitochondrial DNA content and the expression of mitochondrial-specific transcription factors. All these findings demonstrate the neuroprotective effect of osthole in spinal cord ischemia-reperfusion injury model and suggest that oshtole-induced neuroprotection was mediated by mitochondrial biogenesis-independent inhibition of mitochondrial dysfunction. Copyright © 2013 Elsevier Inc. All rights reserved.

Accelerated recovery of renal mitochondrial and tubule homeostasis with SIRT1/PGC-1α activation following ischemia–reperfusion injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Funk, Jason A., E-mail: funkj@musc.edu; Schnellmann, Rick G., E-mail: schnell@musc.edu; Ralph H. Johnson VA Medical Center, Charleston, SC 29401

Kidney ischemia–reperfusion (I/R) injury elicits cellular injury in the proximal tubule, and mitochondrial dysfunction is a pathological consequence of I/R. Promoting mitochondrial biogenesis (MB) as a repair mechanism after injury may offer a unique strategy to restore both mitochondrial and organ function. Rats subjected to bilateral renal pedicle ligation for 22 min were treated once daily with the SIRT1 activator SRT1720 (5 mg/kg) starting 24 h after reperfusion until 72 h–144 h. SIRT1 expression was elevated in the renal cortex of rats after I/R + vehicle treatment (IRV), but was associated with less nuclear localization. SIRT1 expression was even furthermore » augmented and nuclear localization was restored in the kidneys of rats after I/R + SRT1720 treatment (IRS). PGC-1α was elevated at 72 h–144 h in IRV and IRS kidneys; however, SRT1720 treatment induced deacetylation of PGC-1α, a marker of activation. Mitochondrial proteins ATP synthase β, COX I, and NDUFB8, as well as mitochondrial respiration, were diminished 24 h–144 h in IRV rats, but were partially or fully restored in IRS rats. Urinary kidney injury molecule-1 (KIM-1) was persistently elevated in both IRV and IRS rats; however, KIM-1 tissue expression was attenuated in IRS rats. Additionally, sustained loss of Na{sup +},K{sup +}–ATPase expression and basolateral localization and elevated vimentin in IRV rats was normalized in IRS rats, suggesting restoration of a differentiated, polarized tubule epithelium. The results suggest that SRT1720 treatment expedited recovery of mitochondrial protein expression and function by enhancing MB, which was associated with faster proximal tubule repair. Targeting MB may offer unique therapeutic strategy following ischemic injury. - Highlights: • We examined recovery of mitochondrial and renal function after ischemia–reperfusion. • SRT1720 treatment after I/R induced mitochondrial biogenesis via SIRT1/PGC-1α. • Recovery of mitochondrial function was expedited with SRT1720 treatment. • Restoration of tubule homeostasis was expedited with SRT1720 treatment. • Activators of SIRT1 and PGC-1α may offer new therapeutic targets for AKI.« less

Skeletal muscle mitochondrial health and spinal cord injury.

PubMed

O'Brien, Laura C; Gorgey, Ashraf S

2016-10-18

Mitochondria are the main source of cellular energy production and are dynamic organelles that undergo biogenesis, remodeling, and degradation. Mitochondrial dysfunction is observed in a number of disease states including acute and chronic central or peripheral nervous system injury by traumatic brain injury, spinal cord injury (SCI), and neurodegenerative disease as well as in metabolic disturbances such as insulin resistance, type II diabetes and obesity. Mitochondrial dysfunction is most commonly observed in high energy requiring tissues like the brain and skeletal muscle. In persons with chronic SCI, changes to skeletal muscle may include remarkable atrophy and conversion of muscle fiber type from oxidative to fast glycolytic, combined with increased infiltration of intramuscular adipose tissue. These changes contribute to a proinflammatory environment, glucose intolerance and insulin resistance. The loss of metabolically active muscle combined with inactivity predisposes individuals with SCI to type II diabetes and obesity. The contribution of skeletal muscle mitochondrial density and electron transport chain activity to the development of the aforementioned comorbidities following SCI is unclear. A better understanding of the mechanisms involved in skeletal muscle mitochondrial dynamics is imperative to designing and testing effective treatments for this growing population. The current editorial will review ways to study mitochondrial function and the importance of improving skeletal muscle mitochondrial health in clinical populations with a special focus on chronic SCI.

Accelerated recovery of renal mitochondrial and tubule homeostasis with SIRT1/PGC-1α activation following ischemia-reperfusion injury.

PubMed

Funk, Jason A; Schnellmann, Rick G

2013-12-01

Kidney ischemia-reperfusion (I/R) injury elicits cellular injury in the proximal tubule, and mitochondrial dysfunction is a pathological consequence of I/R. Promoting mitochondrial biogenesis (MB) as a repair mechanism after injury may offer a unique strategy to restore both mitochondrial and organ function. Rats subjected to bilateral renal pedicle ligation for 22 min were treated once daily with the SIRT1 activator SRT1720 (5mg/kg) starting 24h after reperfusion until 72h-144 h. SIRT1 expression was elevated in the renal cortex of rats after I/R+vehicle treatment (IRV), but was associated with less nuclear localization. SIRT1 expression was even further augmented and nuclear localization was restored in the kidneys of rats after I/R+SRT1720 treatment (IRS). PGC-1α was elevated at 72 h-144 h in IRV and IRS kidneys; however, SRT1720 treatment induced deacetylation of PGC-1α, a marker of activation. Mitochondrial proteins ATP synthase β, COX I, and NDUFB8, as well as mitochondrial respiration, were diminished 24h-144 h in IRV rats, but were partially or fully restored in IRS rats. Urinary kidney injury molecule-1 (KIM-1) was persistently elevated in both IRV and IRS rats; however, KIM-1 tissue expression was attenuated in IRS rats. Additionally, sustained loss of Na(+),K(+)-ATPase expression and basolateral localization and elevated vimentin in IRV rats was normalized in IRS rats, suggesting restoration of a differentiated, polarized tubule epithelium. The results suggest that SRT1720 treatment expedited recovery of mitochondrial protein expression and function by enhancing MB, which was associated with faster proximal tubule repair. Targeting MB may offer unique therapeutic strategy following ischemic injury. © 2013. Published by Elsevier Inc. All rights reserved.

Soluble guanylate cyclase activation during ischemic injury in mice protects against postischemic inflammation at the mitochondrial level.

PubMed

Wang, Derek Z; Jones, Allan W; Wang, Walter Z; Wang, Meifang; Korthuis, Ronald J

2016-05-01

The aim was to determine whether treatment with BAY 60-2770, a selective activator of oxidized soluble guanylate cyclase (sGC), near the end of an ischemic event would prevent postischemic inflammation and mitochondrial dysfunction in wild-type (WT) and heme oxygenase-1 KO (HO-1(-/-)) mice. This protocol prevented increases in leukocyte rolling (LR) and adhesion (LA) to intestinal venules along with elevated TNFα and circulating neutrophil levels that accompany ischemia-reperfusion (I/R) in both animal models. We further hypothesized that a component of BAY 60-2770 treatment involves maintenance of mitochondrial membrane integrity during I/R. Measurements on isolated enterocytes of calcein fluorescence (mitochondrial permeability) and JC-1 fluorescence ratio (mitochondrial membrane potential) were reduced by I/R, indicating formation of mitochondrial permeability transition pores (mPTP). These effects were abrogated by BAY 60-2770 as well as cyclosporin A and SB-216763, which prevented mPTP opening and inhibited glycogen synthase kinase-3β (GSK-3β), respectively. Western blots of WT and HO-1(-/-) enterocytes indicated that GSK-3β phosphorylation on Ser(9) (inhibitory site) was reduced by half following I/R alone (increased GSK-3β activity) and increased by one-third (reduced GSK-3β activity) following BAY 60-2770. Other investigators have associated phosphorylation of the GSK-3β substrate cyclophilin D (pCyPD) with mPTP formation. We observed a 60% increase in pCyPD after I/R, whereas BAY 60-2770 treatment of sham and I/R groups reduced pCyPD by about 20%. In conclusion, selective activation of oxidized sGC of WT and HO-1(-/-) during ischemia protects against I/R-induced inflammation and preserves mucosal integrity in part by reducing pCyPD production and mPTP formation. Copyright © 2016 the American Physiological Society.

Neuroprotective effects of diazoxide and its antagonism by glibenclamide in pyramidal neurons of rat hippocampus subjected to ischemia-reperfusion-induced injury.

PubMed

Zarch, Anoushiravan Vakili; Toroudi, Hamidreza Pazoki; Soleimani, Mansooreh; Bakhtiarian, Azam; Katebi, Majid; Djahanguiri, Bijan

2009-01-01

Mitochondrial ATP-sensitive potassium channel opener, diazoxide, is shown to have protective effect on the heart and brain following ischemia-reperfusion-induced injury (IR/II). However, the detailed effect of diazoxide and its antagonist on neuronal death, mitochondrial changes, and apoptosis in cerebral IR/II has not fully studied. IR/II was induced in rats by the 4-vessel occlusion model. Neuronal cell death and mitochondrial changes in CA1-CA4 pyramidal cells of the hippocampus were studied by light and electron microscopy, respectively. Apoptosis was assessed by measuring the amount of protein expressed by Bax and Bcl-2 genes. In light microscopy studies, the number of total and normal cells were increased only following 18 mg/kg of diazoxide. Lower doses (2 and 6 mg/kg) failed to change the cell numbers. All three doses of glibenclamide (1, 5, and 25 mg/kg) decreased the number of total and normal cell populations. In electron microscopy studies, different doses of diazoxide and glibenclamide prevented and aggravated the IR-induced morphological changes, respectively. Western blot analysis showed that diazoxide and glibenclamide inhibited and enhanced Bax protein expression respectively. Regarding Bcl-2 expression, only diazoxide showed a significant enhancement of gene expression. In conclusion, the results show that diazoxide can exhibit neuroprotective effects against IR/II in hippocampal regions, possibly through the opening of mitochondrial ATP-sensitive K(+) channels.

Mitochondrial Division Inhibitor 1 (mdivi-1) Protects Neurons against Excitotoxicity through the Modulation of Mitochondrial Function and Intracellular Ca2+ Signaling.

PubMed

Ruiz, Asier; Alberdi, Elena; Matute, Carlos

2018-01-01

Excessive dynamin related protein 1 (Drp1)-triggered mitochondrial fission contributes to apoptosis under pathological conditions and therefore it has emerged as a promising therapeutic target. Mitochondrial division inhibitor 1 (mdivi-1) inhibits Drp1-dependent mitochondrial fission and is neuroprotective in several models of brain ischemia and neurodegeneration. However, mdivi-1 also modulates mitochondrial function and oxidative stress independently of Drp1, and consequently the mechanisms through which it protects against neuronal injury are more complex than previously foreseen. In this study, we have analyzed the effects of mdivi-1 on mitochondrial dynamics, Ca 2+ signaling, mitochondrial bioenergetics and cell viability during neuronal excitotoxicity in vitro . Time-lapse fluorescence microscopy revealed that mdivi-1 blocked NMDA-induced mitochondrial fission but not that triggered by sustained AMPA receptor activation, showing that mdivi-1 inhibits excitotoxic mitochondrial fragmentation in a source specific manner. Similarly, mdivi-1 strongly reduced NMDA-triggered necrotic-like neuronal death and, to a lesser extent, AMPA-induced toxicity. Interestingly, neuroprotection provided by mdivi-1 against NMDA, but not AMPA, correlated with a reduction in cytosolic Ca 2+ ([Ca 2+ ] cyt ) overload and calpain activation indicating additional cytoprotective mechanisms. Indeed, mdivi-1 depolarized mitochondrial membrane and depleted ER Ca 2+ content, leading to attenuation of mitochondrial [Ca 2+ ] increase and enhancement of the integrated stress response (ISR) during NMDA receptor activation. Finally, lentiviral knockdown of Drp1 did not rescue NMDA-induced mitochondrial fission and toxicity, indicating that neuroprotective activity of mdivi-1 is Drp1-independent. Together, these results suggest that mdivi-1 induces a Drp1-independent protective phenotype that prevents predominantly NMDA receptor-mediated excitotoxicity through the modulation of mitochondrial function and intracellular Ca 2+ signaling.

Agmatine effects on mitochondrial membrane potential and NF-κB activation protect against rotenone-induced cell damage in human neuronal-like SH-SY5Y cells.

PubMed

Condello, Salvatore; Currò, Monica; Ferlazzo, Nadia; Caccamo, Daniela; Satriano, Joseph; Ientile, Riccardo

2011-01-01

Agmatine, an endogenous arginine metabolite, has been proposed as a novel neuromodulator that plays protective roles in the CNS in several models of cellular damage. However, the mechanisms involved in these protective effects in neurodegenerative diseases are poorly understood. The present study was undertaken to investigate the effects of agmatine on cell injury induced by rotenone, commonly used in establishing in vivo and in vitro models of Parkinson's disease, in human-derived dopaminergic neuroblastoma cell line (SH-SY5Y). We report that agmatine dose-dependently suppressed rotenone-induced cellular injury through a reduction of oxidative stress. Similar effects were obtained by spermine, suggesting a scavenging effect for these compounds. However, unlike spermine, agmatine also prevented rotenone-induced nuclear factor-κB nuclear translocation and mitochondrial membrane potential dissipation. Furthermore, rotenone-induced increase in apoptotic markers, such as caspase 3 activity, Bax expression and cytochrome c release, was significantly attenuated with agmatine treatment. These findings demonstrate mitochondrial preservation with agmatine in a rotenone model of apoptotic cell death, and that the neuroprotective action of agmatine appears because of suppressing apoptotic signalling mechanisms. Thus, agmatine may have therapeutic potential in the treatment of Parkinson's disease by protecting dopaminergic neurons.

An Antimicrobial Peptidomimetic Induces Mucorales Cell Death through Mitochondria-Mediated Apoptosis

PubMed Central

Barbu, E. Magda; Shirazi, Fazal; McGrath, Danielle M.; Albert, Nathaniel; Sidman, Richard L.; Pasqualini, Renata; Arap, Wadih; Kontoyiannis, Dimitrios P.

2013-01-01

The incidence of mucormycosis has dramatically increased in immunocompromised patients. Moreover, the array of cellular targets whose inhibition results in fungal cell death is rather limited. Mitochondria have been mechanistically identified as central regulators of detoxification and virulence in fungi. Our group has previously designed and developed a proteolytically-resistant peptidomimetic motif D(KLAKLAK)2 with pleiotropic action ranging from targeted (i.e., ligand-directed) activity against cancer and obesity to non-targeted activity against antibiotic resistant gram-negative rods. Here we evaluated whether this non-targeted peptidomimetic motif is active against Mucorales. We show that D(KLAKLAK)2 has marked fungicidal action, inhibits germination, and reduces hyphal viability. We have also observed cellular changes characteristic of apoptosis in D(KLAKLAK)2-treated Mucorales cells. Moreover, the fungicidal activity was directly correlated with vacuolar injury, mitochondrial swelling and mitochondrial membrane depolarization, intracellular reactive oxygen species accumulation (ROS), and increased caspase-like enzymatic activity. Finally, these apoptotic features were prevented by the addition of the ROS scavenger N-acetyl-cysteine indicating mechanistic pathway specificity. Together, these findings indicate that D(KLAKLAK)2 makes Mucorales exquisitely susceptible via mitochondrial injury-induced apoptosis. This prototype may serve as a candidate drug for the development of translational applications against mucormycosis and perhaps other fungal infections. PMID:24098573

An antimicrobial peptidomimetic induces Mucorales cell death through mitochondria-mediated apoptosis.

PubMed

Barbu, E Magda; Shirazi, Fazal; McGrath, Danielle M; Albert, Nathaniel; Sidman, Richard L; Pasqualini, Renata; Arap, Wadih; Kontoyiannis, Dimitrios P

2013-01-01

The incidence of mucormycosis has dramatically increased in immunocompromised patients. Moreover, the array of cellular targets whose inhibition results in fungal cell death is rather limited. Mitochondria have been mechanistically identified as central regulators of detoxification and virulence in fungi. Our group has previously designed and developed a proteolytically-resistant peptidomimetic motif D(KLAKLAK)2 with pleiotropic action ranging from targeted (i.e., ligand-directed) activity against cancer and obesity to non-targeted activity against antibiotic resistant gram-negative rods. Here we evaluated whether this non-targeted peptidomimetic motif is active against Mucorales. We show that D(KLAKLAK)2 has marked fungicidal action, inhibits germination, and reduces hyphal viability. We have also observed cellular changes characteristic of apoptosis in D(KLAKLAK)2-treated Mucorales cells. Moreover, the fungicidal activity was directly correlated with vacuolar injury, mitochondrial swelling and mitochondrial membrane depolarization, intracellular reactive oxygen species accumulation (ROS), and increased caspase-like enzymatic activity. Finally, these apoptotic features were prevented by the addition of the ROS scavenger N-acetyl-cysteine indicating mechanistic pathway specificity. Together, these findings indicate that D(KLAKLAK)2 makes Mucorales exquisitely susceptible via mitochondrial injury-induced apoptosis. This prototype may serve as a candidate drug for the development of translational applications against mucormycosis and perhaps other fungal infections.

Mitochondria localize to injured axons to support regeneration

PubMed Central

Han, Sung Min; Baig, Huma S.; Hammarlund, Marc

2016-01-01

SUMMARY Axon regeneration is essential to restore the nervous system after axon injury. However, the neuronal cell biology that underlies axon regeneration is incompletely understood. Here we use in vivo single-neuron analysis to investigate the relationship between nerve injury, mitochondrial localization, and axon regeneration. Mitochondria translocate into injured axons, so that average mitochondria density increases after injury. Moreover, single-neuron analysis reveals that axons that fail to increase mitochondria have poor regeneration. Experimental alterations to axonal mitochondrial distribution or mitochondrial respiratory chain function result in corresponding changes to regeneration outcomes. Axonal mitochondria are specifically required for growth cone migration, identifying a key energy challenge for injured neurons. Finally, mitochondrial localization to the axon after injury is regulated in part by dual-leucine zipper kinase-1 (DLK-1), a conserved regulator of axon regeneration. These data identify regulation of axonal mitochondria as a new cell biological mechanism that helps determine the regenerative response of injured neurons. PMID:28009276

Inhaled, Nebulized Sodium Nitrite Protects In Murine and Porcine Experimental Models Of Hemorrhagic Shock and Resuscitation by Limiting Mitochondrial Injury

PubMed Central

Kautza, Benjamin; Gomez, Hernando; Escobar, Daniel; Corey, Catherine; Ataya, Bilal; Luciano, Jason; Botero, Ana Maria; Gordon, Lisa; Brumfield, John; Martinez, Silvia; Holder, Andre; Ogundele, Olufunmilayo; Pinsky, Michael; Shiva, Sruti; Zuckerbraun, Brian S.

2015-01-01

Objective The cellular injury that occurs in the setting of hemorrhagic shock and resuscitation (HS/R) affects all tissue types and can drive altered inflammatory responses. Resuscitative adjuncts hold the promise of decreasing such injury. Here we test the hypothesis that sodium nitrite (NaNO2), delivered as a nebulized solution via an inhalational route, protects against injury and inflammation from HS/R. Methods Mice underwent HS/R to a mean arterial pressure (MAP) of 20 or 25 mmHg. Mice were resuscitated with Lactated Ringers after 90–120 minutes of hypotension. Mice were randomized to receive nebulized NaNO2 via a flow through chamber (30mg in 5mL PBS). Pigs (30–35 kg) were anesthetized and bled to a MAP of 30–40 mmHg for 90 minutes, randomized to receive NaNO2 (11 mg in 2.5 mL PBS) nebulized into the ventilator circuit starting 60 minutes into the hypotensive period, followed by initial resuscitation with Hextend. Pigs had ongoing resuscitation and support for up to four hours. Hemodynamic data were collected continuously. Results NaNO2 limited organ injury and inflammation in murine hemorrhagic shock. A nitrate/nitrite depleted diet exacerbated organ injury, as well as mortality, and inhaled NaNO2 significantly reversed this effect. Furthermore, NaNO2 limited mitochondrial oxidant injury. In porcine HS/R, NaNO2 had no significant influence on shock induced hemodynamics. NaNO2 limited hypoxia/reoxia or HS/R-induced mitochondrial injury and promoted mitochondrial fusion. Conclusion NaNO2 may be a useful adjunct to shock resuscitation based on its limitation of mitochondrial injury. PMID:26410351

Regulation of Mitochondrial Function and Glutamatergic System Are the Target of Guanosine Effect in Traumatic Brain Injury.

PubMed

Dobrachinski, Fernando; da Rosa Gerbatin, Rogério; Sartori, Gláubia; Ferreira Marques, Naiani; Zemolin, Ana Paula; Almeida Silva, Luiz Fernando; Franco, Jeferson Luis; Freire Royes, Luiz Fernando; Rechia Fighera, Michele; Antunes Soares, Félix Alexandre

2017-04-01

Traumatic brain injury (TBI) is a highly complex multi-factorial disorder. Experimental trauma involves primary and secondary injury cascades that underlie delayed neuronal dysfunction and death. Mitochondrial dysfunction and glutamatergic excitotoxicity are the hallmark mechanisms of damage. Accordingly, a successful pharmacological intervention requires a multi-faceted approach. Guanosine (GUO) is known for its neuromodulator effects in various models of brain pathology, specifically those that involve the glutamatergic system. The aim of the study was to investigate the GUO effects against mitochondrial damage in hippocampus and cortex of rats subjected to TBI, as well as the relationship of this effect with the glutamatergic system. Adult male Wistar rats were subjected to a unilateral moderate fluid percussion brain injury (FPI) and treated 15 min later with GUO (7.5 mg/kg) or vehicle (saline 0.9%). Analyses were performed in hippocampus and cortex 3 h post-trauma and revealed significant mitochondrial dysfunction, characterized by a disrupted membrane potential, unbalanced redox system, decreased mitochondrial viability, and complex I inhibition. Further, disruption of Ca 2+ homeostasis and increased mitochondrial swelling was also noted. Our results showed that mitochondrial dysfunction contributed to decreased glutamate uptake and levels of glial glutamate transporters (glutamate transporter 1 and glutamate aspartate transporter), which leads to excitotoxicity. GUO treatment ameliorated mitochondrial damage and glutamatergic dyshomeostasis. Thus, GUO might provide a new efficacious strategy for the treatment acute physiological alterations secondary to TBI.

Parkin regulates mitophagy and mitochondrial function to protect against alcohol-induced liver injury and steatosis in mice

PubMed Central

Williams, Jessica A.; Ni, Hong-Min; Ding, Yifeng

2015-01-01

Alcoholic liver disease claims two million lives per year. We previously reported that autophagy protected against alcohol-induced liver injury and steatosis by removing damaged mitochondria. However, the mechanisms for removal of these mitochondria are unknown. Parkin is an evolutionarily conserved E3 ligase that is recruited to damaged mitochondria to initiate ubiquitination of mitochondrial outer membrane proteins and subsequent mitochondrial degradation by mitophagy. In addition to its role in mitophagy, Parkin has been shown to have other roles in maintaining mitochondrial function. We investigated whether Parkin protected against alcohol-induced liver injury and steatosis using wild-type (WT) and Parkin knockout (KO) mice treated with alcohol by the acute-binge and Gao-binge (chronic plus acute-binge) models. We found that Parkin protected against liver injury in both alcohol models, likely because of Parkin's role in maintaining a population of healthy mitochondria. Alcohol caused greater mitochondrial damage and oxidative stress in Parkin KO livers compared with WT livers. After alcohol treatment, Parkin KO mice had severely swollen and damaged mitochondria that lacked cristae, which were not seen in WT mice. Furthermore, Parkin KO mice had decreased mitophagy, β-oxidation, mitochondrial respiration, and cytochrome c oxidase activity after acute alcohol treatment compared with WT mice. Interestingly, liver mitochondria seemed able to adapt to alcohol treatment, but Parkin KO mouse liver mitochondria had less capacity to adapt to Gao-binge treatment compared with WT mouse liver mitochondria. Overall, our findings indicate that Parkin is an important mediator of protection against alcohol-induced mitochondrial damage, steatosis, and liver injury. PMID:26159696

The Mammalian-Specific Protein Armcx1 Regulates Mitochondrial Transport during Axon Regeneration.

PubMed

Cartoni, Romain; Norsworthy, Michael W; Bei, Fengfeng; Wang, Chen; Li, Siwei; Zhang, Yiling; Gabel, Christopher V; Schwarz, Thomas L; He, Zhigang

2016-12-21

Mitochondrial transport is crucial for neuronal and axonal physiology. However, whether and how it impacts neuronal injury responses, such as neuronal survival and axon regeneration, remain largely unknown. In an established mouse model with robust axon regeneration, we show that Armcx1, a mammalian-specific gene encoding a mitochondria-localized protein, is upregulated after axotomy in this high regeneration condition. Armcx1 overexpression enhances mitochondrial transport in adult retinal ganglion cells (RGCs). Importantly, Armcx1 also promotes both neuronal survival and axon regeneration after injury, and these effects depend on its mitochondrial localization. Furthermore, Armcx1 knockdown undermines both neuronal survival and axon regeneration in the high regenerative capacity model, further supporting a key role of Armcx1 in regulating neuronal injury responses in the adult central nervous system (CNS). Our findings suggest that Armcx1 controls mitochondrial transport during neuronal repair. Copyright © 2016 Elsevier Inc. All rights reserved.

Fluid Mechanical Forces and Endothelial Mitochondria: A Bioengineering Perspective.

PubMed

Scheitlin, Christopher G; Nair, Devi M; Crestanello, Juan A; Zweier, Jay L; Alevriadou, B Rita

2014-12-01

Endothelial cell dysfunction is the hallmark of every cardiovascular disease/condition, including atherosclerosis and ischemia/reperfusion injury. Fluid shear stress acting on the vascular endothelium is known to regulate cell homeostasis. Altered hemodynamics is thought to play a causative role in endothelial dysfunction. The dysfunction is associated with/preceded by mitochondrial oxidative stress. Studies by our group and others have shown that the form and/or function of the mitochondrial network are affected when endothelial cells are exposed to shear stress in the absence or presence of additional physicochemical stimuli. The present review will summarize the current knowledge on the interconnections among intracellular Ca 2+ - nitric oxide - mitochondrial reactive oxygen species, mitochondrial fusion/fission, autophagy/mitophagy, and cell apoptosis vs. survival. More specifically, it will list the evidence on potential regulation of the above intracellular species and processes by the fluid shear stress acting on the endothelium under either physiological flow conditions or during reperfusion (following a period of ischemia). Understanding how the local hemodynamics affects mitochondrial physiology and the cell redox state may lead to development of novel therapeutic strategies for prevention or treatment of the endothelial dysfunction and, hence, of cardiovascular disease.

Effects of the novel angiotensin II receptor type I antagonist, fimasartan on myocardial ischemia/reperfusion injury.

PubMed

Han, Jin; Park, Sung-Ji; Thu, Vu Thi; Lee, Sung-Ryul; Long, Le Thanh; Kim, Hyoung Kyu; Kim, Nari; Park, Seung Woo; Jeon, Eun-Seok; Kim, Eun-Ji; Yoon, Chang-Hwan; Cho, Goo-Young; Choi, Dong-Ju

2013-10-03

The aim of this study was to investigate the cardioprotective effect of fimasartan, a newly developed angiotensin II receptor type I blocker (ARB), against myocardial ischemia/reperfusion (I/R) injury and to identify the mechanism by which it reduces mitochondrial damage. Fimasartan was administered intravenously to Sprague-Dawley rats (3mg/kg), cardiomyocytes (50 μM), and H9c2 cells (50 μM) before ischemia or hypoxia. Myocardial infarction (MI), echocardiograms, DNA fragmentation, terminal deoxynucleotidyl transferase-mediated dUTP in situ nick-end labeling, immunoblotting, oxygen consumption, confocal microscopic appearance, and L-type Ca(2+) current (ICa,L) were then assessed. Fimasartan pretreatment remarkably reduced the rate of MI and improved cardiac performance well after I/R (n = 9/group). Fimasartan also reduced apoptotic cell death both in vivo and in hypoxia/reoxygenation (H/R)-treated H9c2 cells (n = 5~8/group). H/R-induced mitochondrial O2(-) production and collapse of membrane potential were markedly attenuated in fimasartan-treated cardiomyocytes (n = 4 ~ 6/group). Additionally, mitochondrial Ca(2+) overload during reoxygenation was suppressed by fimasartan (n = 4~6/group), and this was found to be possibly related to the inhibition of ICa,L and mitochondrial Ca(2+) uniporter. Furthermore, fimasartan pretreatment increased phosphorylations of Akt and glycogen synthase kinase-3β (n = 5 ~ 7/group), decreased pro-apoptotic p53 levels, and increased anti-apoptotic Bcl-2 levels (n = 4) during reperfusion. Fimasartan preconditioning has the potential to modulate Bcl-2 and suppress I/R-induced Ca(2+) overload by inhibiting ICa,L and MCU. These beneficial effects could prevent the mitochondrial dysfunction and apoptosis accompanied by I/R. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Endothelial mitochondrial oxidative stress determines podocyte depletion in segmental glomerulosclerosis

PubMed Central

Daehn, Ilse; Casalena, Gabriella; Zhang, Taoran; Shi, Shaolin; Fenninger, Franz; Barasch, Nicholas; Yu, Liping; D’Agati, Vivette; Schlondorff, Detlef; Kriz, Wilhelm; Haraldsson, Borje; Bottinger, Erwin P.

2014-01-01

Focal segmental glomerular sclerosis (FSGS) is a primary kidney disease that is commonly associated with proteinuria and progressive loss of glomerular function, leading to development of chronic kidney disease (CKD). FSGS is characterized by podocyte injury and depletion and collapse of glomerular capillary segments. Progression of FSGS is associated with TGF-β activation in podocytes; however, it is not clear how TGF-β signaling promotes disease. Here, we determined that podocyte-specific activation of TGF-β signaling in transgenic mice and BALB/c mice with Adriamycin-induced glomerulosclerosis is associated with endothelin-1 (EDN1) release by podocytes, which mediates mitochondrial oxidative stress and dysfunction in adjacent endothelial cells via paracrine EDN1 receptor type A (EDNRA) activation. Endothelial dysfunction promoted podocyte apoptosis, and inhibition of EDNRA or scavenging of mitochondrial-targeted ROS prevented podocyte loss, albuminuria, glomerulosclerosis, and renal failure. We confirmed reciprocal crosstalk between podocytes and endothelial cells in a coculture system. Biopsies from patients with FSGS exhibited increased mitochondrial DNA damage, consistent with EDNRA-mediated glomerular endothelial mitochondrial oxidative stress. Our studies indicate that segmental glomerulosclerosis develops as a result of podocyte-endothelial crosstalk mediated by EDN1/EDNRA-dependent mitochondrial dysfunction and suggest that targeting the reciprocal interaction between podocytes and endothelia may provide opportunities for therapeutic intervention in FSGS. PMID:24590287

Caffeic acid attenuates rat liver reperfusion injury through sirtuin 3-dependent regulation of mitochondrial respiratory chain.

PubMed

Mu, Hong-Na; Li, Quan; Pan, Chun-Shui; Liu, Yu-Ying; Yan, Li; Hu, Bai-He; Sun, Kai; Chang, Xin; Zhao, Xin-Rong; Fan, Jing-Yu; Han, Jing-Yan

2015-08-01

Sirtuin 3 (Sirt3) plays critical roles in regulating mitochondrial oxidative metabolism. However, whether Sirt3 is involved in liver ischemia and reperfusion (I/R) injury remains elusive. Caffeic acid (CA) is a natural antioxidant derived from Salvia miltiorrhiza. Whether CA protects against liver I/R injury through regulating Sirt3 and the mitochondrial respiratory chain (MRC) is unclear. This study investigated the effect of CA on liver I/R injury, microcirculatory disturbance, and potential mechanisms, particularly focusing on Sirt3-dependent MRC. Liver I/R of male Sprague-Dawley rats was established by occlusion of portal area vessels for 30 min followed by 120 min of reperfusion. CA (15 mg/kg/h) was continuously infused via the femoral vein starting 30 min before ischemia. After I/R, Sirt3 expression, and MRC activity decreased, acetylation of NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 and succinate dehydrogenase complex, subunit A, flavoprotein variant provoked, and the liver microcirculatory disturbance and injury were observed. Treatment with CA attenuated liver injury, inhibited Sirt3 down-expression, and up-regulated MRC activity. CA attenuated rat liver microcirculatory disturbance and oxidative injury through regulation of Sirt3 and the mitochondrial respiratory chain. Copyright © 2015 Elsevier Inc. All rights reserved.

Blockade of Drp1 rescues oxidative stress-induced osteoblast dysfunction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, Xueqi; Huang, Shengbin; Yu, Qing

Osteoblast dysfunction, induced by oxidative stress, plays a critical role in the pathophysiology of osteoporosis. However, the underlying mechanisms remain unclarified. Imbalance of mitochondrial dynamics has been closely linked to oxidative stress. Here, we reveal an unexplored role of dynamic related protein 1(Drp1), the major regulator in mitochondrial fission, in the oxidative stress-induced osteoblast injury model. We demonstrate that levels of phosphorylation and expression of Drp1 significantly increased under oxidative stress. Blockade of Drp1, through pharmaceutical inhibitor or gene knockdown, significantly protected against H{sub 2}O{sub 2}-induced osteoblast dysfunction, as shown by increased cell viability, improved cellular alkaline phosphatase (ALP) activitymore » and mineralization and restored mitochondrial function. The protective effects of blocking Drp1 in H{sub 2}O{sub 2}-induced osteoblast dysfunction were evidenced by increased mitochondrial function and suppressed production of reactive oxygen species (ROS). These findings provide new insights into the role of the Drp1-dependent mitochondrial pathway in the pathology of osteoporosis, indicating that the Drp1 pathway may be targetable for the development of new therapeutic approaches in the prevention and the treatment of osteoporosis. - Highlights: • Oxidative stress is an early pathological event in osteoporosis. • Imbalance of mitochondrial dynamics are linked to oxidative stress in osteoporosis. • The role of the Drp1-dependent mitochondrial pathway in osteoporosis.« less

Ascorbate and low concentrations of FeSO4 induce Ca2+-dependent pore in rat liver mitochondria.

PubMed

Brailovskaya, I V; Starkov, A A; Mokhova, E N

2001-08-01

Oxidative stress is one of the most frequent causes of tissue and cell injury in various pathologies. The molecular mechanism of mitochondrial damage under conditions of oxidative stress induced in vitro with low concentrations of FeSO4 and ascorbate (vitamin C) was studied. FeSO4 (1-4 microM) added to rat liver mitochondria that were incubated in the presence of 2.3 mM ascorbate induced (with a certain delay) a decrease in membrane potential and high-amplitude swelling. It also significantly decreased the ability of mitochondria to accumulate exogenous Ca2+. All the effects of FeSO4 + ascorbate were essentially prevented by cyclosporin A, a specific inhibitor of the mitochondrial Ca2+-dependent pore (also known as the mitochondrial permeability transition). EGTA restored the membrane potential of mitochondria de-energized with FeSO4 + ascorbate. We hypothesize that oxidative stress induced in vitro with FeSO4 and millimolar concentrations of ascorbate damages mitochondria by inducing the cyclosporin A-sensitive Ca2+-dependent pore in the inner mitochondrial membrane.

[Prevention of Inonotus obliquus polysaccharides for high power microwave radiation induced testicular injury in rats: an experimental research].

PubMed

Zhao, Li-Wei; Zhong, Xiu-Hong; Sun, Yan-Mei; Yang, Shu-Yan; Shen, Nan; Zhang, Yi-Zhong; Yang, Ning-Jiang; Ren, Kuang; Lu, Shi-Jie

2014-07-01

To investigate the effect of Inonotus obliquus polysaccharides on testicular injury induced by exposure to high power microwave (HPM) in rats. A total of 30 male Wistar rats were randomly divided into 5 groups, i.e., the normal control group, the microwave radiation model group, the treatment group, the new microwave radiation model group, and the prevention group, 6 in each group. All rats, except those in the normal control group, were exposed to microwave at an average power density of 200 mW/cm2 for 6 min. Rats in the control group and the model group were administered with normal saline by gastrogavage, once a day. Rats in the treatment group and the prevention group were given with Inonotus obliquus polysaccharides by gastrogavage, 2 mL each time (400 mg/kg body weight), once a day. All rats were sacrificed on the 11th day.The sperm density and the rate of sperm deformity were determined. Pathological changes of testis were observed by light microscope and transmission electron microscope. Short-term HPM irradiation could significantly reduce the sperm density and increase the sperm deformity rate (P < 0.05). Meanwhile, obvious pathological changes of testes occurred. Compared with the two model groups, the sperm density increased and the sperm deformity rate decreased in the treatment group and the prevention group (P < 0.05). Under the light microscope, injuries of spermatogenic cells and stromal cells, as well as vascular dilatation and congestion were obviously alleviated in the treatment group and the prevention group. Mitochondrial swelling and endoplasmic reticulum expansion shown by ultrastructural observation were also significantly alleviated. Of them, injuries of spermatogenic cells and inflammation response were milder in the treatment group than in the prevention group. Inonotus obliquus polysaccharides had significant protective effect on microwave radiation induced testicular injury. Better effect was obtained by therapeutic medication than preventive medication.

Pink1/Parkin-mediated mitophagy play a protective role in cisplatin induced renal tubular epithelial cells injury.

PubMed

Zhao, Chuanyan; Chen, Zhuyun; Xu, Xueqiang; An, Xiaofei; Duan, Suyan; Huang, Zhimin; Zhang, Chengning; Wu, Lin; Zhang, Bo; Zhang, Aihua; Xing, Changying; Yuan, Yanggang

2017-01-15

Cisplatin often causes acute kidney injury (AKI) in the treatment of a wide variety of malignancies. Mitochondrial dysfunction is one of the main reasons for cisplatin nephrotoxicity. Previous study showed that Pink1 and Parkin play central roles in regulating the mitophagy, which is a key protective mechanism by specifically eliminating dysfunctional or damaged mitochondria. However, the mechanisms that modulate mitophagy in cisplatin induced nephrotoxicity remain to be elucidated. The purpose of this study was to investigate the effects of Pink1/Parkin pathway in mitophagy, mitochondrial dysfunction and renal proximal tubular cells injury during cisplatin treatment. In cultured human renal proximal tubular cells, we found that knockdown of Pink1/Parkin induced the aggravation of mitochondrial function, leading to the increase of cell injury through inhibition of mitophagy. Additionally, the overexpression of Pink1/Parkin protected against cisplatin-induced mitochondrial dysfunction and cell injury by promoting mitophagy. Our results provide clear evidence that Pink1/Parkin-dependent mitophagy has identified potential targets for the treatment of cisplatin-induced AKI. Copyright © 2016 Elsevier Inc. All rights reserved.

Ursolic Acid-enriched herba cynomorii extract induces mitochondrial uncoupling and glutathione redox cycling through mitochondrial reactive oxygen species generation: protection against menadione cytotoxicity in h9c2 cells.

PubMed

Chen, Jihang; Wong, Hoi Shan; Ko, Kam Ming

2014-01-27

Herba Cynomorii (Cynomorium songaricum Rupr., Cynomoriaceae) is one of the most commonly used 'Yang-invigorating' tonic herbs in Traditional Chinese Medicine (TCM). An earlier study in our laboratory has demonstrated that HCY2, an ursolic acid-enriched fraction derived from Herba Cynomorii, increased mitochondrial ATP generation capacity (ATP-GC) and induced mitochondrial uncoupling as well as a cellular glutathione response, thereby protecting against oxidant injury in H9c2 cells. In this study, we demonstrated that pre-incubation of H9c2 cells with HCY2 increased mitochondrial reactive oxygen species (ROS) generation in these cells, which is likely an event secondary to the stimulation of the mitochondrial electron transport chain. The suppression of mitochondrial ROS by the antioxidant dimethylthiourea abrogated the HCY2-induced enhancement of mitochondrial uncoupling and glutathione reductase (GR)-mediated glutathione redox cycling, and also protected against menadione-induced cytotoxicity. Studies using specific inhibitors of uncoupling protein and GR suggested that the HCY2-induced mitochondrial uncoupling and glutathione redox cycling play a determining role in the cytoprotection against menadione-induced oxidant injury in H9c2 cells. Experimental evidence obtained thus far supports the causal role of HCY2-induced mitochondrial ROS production in eliciting mitochondrial uncoupling and glutathione antioxidant responses, which offer cytoprotection against oxidant injury in H9c2 cells.

Chlorogenic acid ameliorates endotoxin-induced liver injury by promoting mitochondrial oxidative phosphorylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yan; College of Food Safety, Guizhou Medical University, Guiyang 550025; Ruan, Zheng, E-mail: ruanzheng@ncu.edu.cn

Acute or chronic hepatic injury is a common pathology worldwide. Mitochondrial dysfunction and the depletion of adenosine triphosphate (ATP) play important roles in liver injury. Chlorogenic acids (CGA) are some of the most abundant phenolic acids in human diet. This study was designed to test the hypothesis that CGA may protect against chronic lipopolysaccharide (LPS)-induced liver injury by modulating mitochondrial energy generation. CGA decreased the activities of serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase. The contents of ATP and adenosine monophosphate (AMP), as well as the ratio of AMP/ATP, were increased after CGA supplementation. The activities of enzymes thatmore » are involved in glycolysis were reduced, while those of enzymes involved in oxidative phosphorylation were increased. Moreover, phosphorylated AMP-activated protein kinase (AMPK), and mRNA levels of AMPK-α, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial DNA transcription factor A were increased after CGA supplementation. Collectively, these findings suggest that the hepatoprotective effect of CGA might be associated with enhanced ATP production, the stimulation of mitochondrial oxidative phosphorylation and the inhibition of glycolysis. - Highlights: • Dietary supplementation with chlorogenic acid (CGA) improved endotoxin-induced liver injury. • Chlorogenic acid enhances ATP increase and shifts energy metabolism, which is correlated with up-regulation AMPK and PGC-1α. • The possible mechanism of CGA on mitochondrial biogenesis was correlated with up-regulation AMPK and PGC-1α.« less

The Compound Chinese Medicine “Kang Fu Ling” Protects against High Power Microwave-Induced Myocardial Injury

PubMed Central

Zhang, Xueyan; Gao, Yabing; Dong, Ji; Wang, Shuiming; Yao, Binwei; Zhang, Jing; Hu, Shaohua; Xu, Xinping; Zuo, Hongyan; Wang, Lifeng; Zhou, Hongmei; Zhao, Li; Peng, Ruiyun

2014-01-01

Background The prevention and treatment of Microwave-caused cardiovascular injury remains elusive. This study investigated the cardiovascular protective effects of compound Chinese medicine “Kang Fu Ling” (KFL) against high power microwave (HPM)-induced myocardial injury and the role of the mitochondrial permeability transition pore (mPTP) opening in KFL protection. Methods Male Wistar rats (100) were divided into 5 equal groups: no treatment, radiation only, or radiation followed by treatment with KFL at 0.75, 1.5, or 3 g/kg/day. Electrocardiography was used to Electrophysiological examination. Histological and ultrastructural changes in heart tissue and isolated mitochondria were observed by light microscope and electron microscopy. mPTP opening and mitochondrial membrane potential were detected by confocal laser scanning microscopy and fluorescence analysis. Connexin-43 (Cx-43) and endothelial nitric oxide synthase (eNOS) were detected by immunohistochemistry. The expression of voltage-dependent anion channel (VDAC) was detected by western blotting. Results At 7 days after radiation, rats without KFL treatment showed a significantly lower heart rate (P<0.01) than untreated controls and a J point shift. Myocyte swelling and rearrangement were evident. Mitochondria exhibited rupture, and decreased fluorescence intensity, suggesting opening of mPTP and a consequent reduction in mitochondrial membrane potential. After treatment with 1.5 g/kg/day KFL for 7 d, the heart rate increased significantly (P<0.01), and the J point shift was reduced flavorfully (P<0.05) compared to untreated, irradiated rats; myocytes and mitochondria were of normal morphology. The fluorescence intensities of dye-treated mitochondria were also increased, suggesting inhibition of mPTP opening and preservation of the mitochondrial membrane potential. The microwave-induced decrease of Cx-43 and VDAC protein expression was significantly reversed. Conclusion Microwave radiation can cause electrophysiological, histological and ultrastructural changes in the heart. KFL at 1.5 g/kg/day had the greatest protective effect on these cardiovascular events. mPTP plays an important role in the protective effects of KFL against microwave-radiation-induced myocardial injury. PMID:24992449

Is cell aging caused by respiration-dependent injury to the mitochondrial genome

NASA Technical Reports Server (NTRS)

Fleming, J. E.; Yengoyan, L. S.; Miquel, J.; Cottrell, S. F.; Economos, A. C.

1982-01-01

Though intrinsic mitochondrial aging has been considered before as a possible cause of cellular senescence, the mechanisms of such mitochondrial aging have remained obscure. In this article, the hypothesis of free-radical-induced inhibition of mitochondrial replenishment in fixed postmitotic cells is expanded. It is maintained that the respiration-dependent production of superoxide and hydroxyl radicals may not be fully counteracted, leading to a continuous production of lipoperoxides and malonaldehyde in actively respiring mitochondria. These compounds, in turn, can easily react with the mitochondrial DNA which is in close spatial relationship with the inner mitochondrial membrane, producing an injury that the mitochondria may be unable to counteract because of their apparent lack of adequate repair mechanisms. Mitochondrial division may thus be inhibited leading to age-related reduction of mitochondrial numbers, a deficit in energy production with a concomitant decrease in protein synthesis, deterioration of physiological performance, and, therefore, of organismic performance.

The abolishment of anesthesia-induced cognitive impairment by timely protection of mitochondria in the developing rat brain: the importance of free oxygen radicals and mitochondrial integrity.

PubMed

Boscolo, A; Starr, J A; Sanchez, V; Lunardi, N; DiGruccio, M R; Ori, C; Erisir, A; Trimmer, P; Bennett, J; Jevtovic-Todorovic, V

2012-03-01

Early exposure to general anesthesia (GA) causes developmental neuroapoptosis in the mammalian brain and long-term cognitive impairment. Recent evidence suggests that GA also causes functional and morphological impairment of the immature neuronal mitochondria. Injured mitochondria could be a significant source of reactive oxygen species (ROS), which, if not scavenged in timely fashion, may cause excessive lipid peroxidation and damage of cellular membranes. We examined whether early exposure to GA results in ROS upregulation and whether mitochondrial protection and ROS scavenging prevent GA-induced pathomorphological and behavioral impairments. We exposed 7-day-old rats to GA with or without either EUK-134, a synthetic ROS scavenger, or R(+) pramipexole (PPX), a synthetic aminobenzothiazol derivative that restores mitochondrial integrity. We found that GA causes extensive ROS upregulation and lipid peroxidation, as well as mitochondrial injury and neuronal loss in the subiculum. As compared to rats given only GA, those also given PPX or EUK-134 had significantly downregulated lipid peroxidation, preserved mitochondrial integrity, and significantly less neuronal loss. The subiculum is highly intertwined with the hippocampal CA1 region, anterior thalamic nuclei, and both entorhinal and cingulate cortices; hence, it is important in cognitive development. We found that PPX or EUK-134 co-treatment completely prevented GA-induced cognitive impairment. Because mitochondria are vulnerable to GA-induced developmental neurotoxicity, they could be an important therapeutic target for adjuvant therapy aimed at improving the safety of commonly used GAs. Copyright © 2011 Elsevier Inc. All rights reserved.

Steatotic livers are susceptible to normothermic ischemia-reperfusion injury from mitochondrial Complex-I dysfunction

PubMed Central

Chu, Michael JJ; Premkumar, Rakesh; Hickey, Anthony JR; Jiang, Yannan; Delahunt, Brett; Phillips, Anthony RJ; Bartlett, Adam SJR

2016-01-01

AIM: To assess the effects of ischemic preconditioning (IPC, 10-min ischemia/10-min reperfusion) on steatotic liver mitochondrial function after normothermic ischemia-reperfusion injury (IRI). METHODS: Sixty male Sprague-Dawley rats were fed 8-wk with either control chow or high-fat/high-sucrose diet inducing > 60% mixed steatosis. Three groups (n = 10/group) for each dietary state were tested: (1) the IRI group underwent 60 min partial hepatic ischemia and 4 h reperfusion; (2) the IPC group underwent IPC prior to same standard IRI; and (3) sham underwent the same surgery without IRI or IPC. Hepatic mitochondrial function was analyzed by oxygraphs. Mitochondrial Complex-I, Complex-II enzyme activity, serum alanine aminotransferase (ALT), and histological injury were measured. RESULTS: Steatotic-IRI livers had a greater increase in ALT (2476 ± 166 vs 1457 ± 103 IU/L, P < 0.01) and histological injury following IRI compared to the lean liver group. Steatotic-IRI demonstrated lower Complex-I activity at baseline [78.4 ± 2.5 vs 116.4 ± 6.0 nmol/(min.mg protein), P < 0.001] and following IRI [28.0 ± 6.2 vs 104.3 ± 12.6 nmol/(min.mg protein), P < 0.001]. Steatotic-IRI also demonstrated impaired Complex-I function post-IRI compared to the lean liver IRI group. Complex-II activity was unaffected by hepatic steatosis or IRI. Lean liver mitochondrial function was unchanged following IRI. IPC normalized ALT and histological injury in steatotic livers but had no effect on overall steatotic liver mitochondrial function or individual mitochondrial complex enzyme activities. CONCLUSION: Warm IRI impairs steatotic liver Complex-I activity and function. The protective effects of IPC in steatotic livers may not be mediated through mitochondria. PMID:27217699

Parkin regulates mitophagy and mitochondrial function to protect against alcohol-induced liver injury and steatosis in mice.

PubMed

Williams, Jessica A; Ni, Hong-Min; Ding, Yifeng; Ding, Wen-Xing

2015-09-01

Alcoholic liver disease claims two million lives per year. We previously reported that autophagy protected against alcohol-induced liver injury and steatosis by removing damaged mitochondria. However, the mechanisms for removal of these mitochondria are unknown. Parkin is an evolutionarily conserved E3 ligase that is recruited to damaged mitochondria to initiate ubiquitination of mitochondrial outer membrane proteins and subsequent mitochondrial degradation by mitophagy. In addition to its role in mitophagy, Parkin has been shown to have other roles in maintaining mitochondrial function. We investigated whether Parkin protected against alcohol-induced liver injury and steatosis using wild-type (WT) and Parkin knockout (KO) mice treated with alcohol by the acute-binge and Gao-binge (chronic plus acute-binge) models. We found that Parkin protected against liver injury in both alcohol models, likely because of Parkin's role in maintaining a population of healthy mitochondria. Alcohol caused greater mitochondrial damage and oxidative stress in Parkin KO livers compared with WT livers. After alcohol treatment, Parkin KO mice had severely swollen and damaged mitochondria that lacked cristae, which were not seen in WT mice. Furthermore, Parkin KO mice had decreased mitophagy, β-oxidation, mitochondrial respiration, and cytochrome c oxidase activity after acute alcohol treatment compared with WT mice. Interestingly, liver mitochondria seemed able to adapt to alcohol treatment, but Parkin KO mouse liver mitochondria had less capacity to adapt to Gao-binge treatment compared with WT mouse liver mitochondria. Overall, our findings indicate that Parkin is an important mediator of protection against alcohol-induced mitochondrial damage, steatosis, and liver injury. Copyright © 2015 the American Physiological Society.

Disruption of Redox Homeostasis in Tumor Necrosis Factor-Induced Apoptosis in a Murine Hepatocyte Cell Line

PubMed Central

Pierce, Robert H.; Campbell, Jean S.; Stephenson, Alyssa B.; Franklin, Christopher C.; Chaisson, Michelle; Poot, Martin; Kavanagh, Terrance J.; Rabinovitch, Peter S.; Fausto, Nelson

2000-01-01

Tumor necrosis factor (TNF) is a mediator of the acute phase response in the liver and can initiate proliferation and cause cell death in hepatocytes. We investigated the mechanisms by which TNF causes apoptosis in hepatocytes focusing on the role of oxidative stress, antioxidant defenses, and mitochondrial damage. The studies were conducted in cultured AML12 cells, a line of differentiated murine hepatocytes. As is the case for hepatocytes in vivo, AML12 cells were not sensitive to cell death by TNF alone, but died by apoptosis when exposed to TNF and a small dose of actinomycin D (Act D). Morphological signs of apoptosis were not detected until 6 hours after the treatment and by 18 hours ∼50% of the cells had died. Exposure of the cells to TNF+Act D did not block NFκB nuclear translocation, DNA binding, or its overall transactivation capacity. Induction of apoptosis was characterized by oxidative stress indicated by the loss of NAD(P)H and glutathione followed by mitochondrial damage that included loss of mitochondrial membrane potential, inner membrane structural damage, and mitochondrial condensation. These changes coincided with cytochrome C release and the activation of caspases-8, -9, and -3. TNF-induced apoptosis was dependent on glutathione levels. In cells with decreased levels of glutathione, TNF by itself in the absence of transcriptional blocking acted as an apoptotic agent. Conversely, the antioxidant α-lipoic acid, that protected against the loss of glutathione in cells exposed to TNF+Act D completely prevented mitochondrial damage, caspase activation, cytochrome C release, and apoptosis. The results demonstrate that apoptosis induced by TNF+Act D in AML12 cells involves oxidative injury and mitochondrial damage. As injury was regulated to a larger extent by the glutathione content of the cells, we suggest that the combination of TNF+Act D causes apoptosis because Act D blocks the transcription of genes required for antioxidant defenses. PMID:10880392

Notch3/Akt signaling contributes to OSM-induced protection against cardiac ischemia/reperfusion injury.

PubMed

Zhang, Mingming; Wang, Chen; Hu, Jianqiang; Lin, Jie; Zhao, Zhijing; Shen, Min; Gao, Haokao; Li, Na; Liu, Min; Zheng, Pengfei; Qiu, Cuiting; Gao, Erhe; Wang, Haichang; Sun, Dongdong

2015-09-01

Oncostatin M (OSM) exhibits many unique biological activities by activating the Oβ receptor. However, its role in myocardial ischemia/reperfusion injury (I/R injury) in mice remains unknown. We investigated whether Notch3/Akt signaling is involved in the regulation of OSM-induced protection against cardiac I/R injury. The effects of OSM were assessed in mice that underwent myocardial I/R injury by OSM treatment or by genetic deficiency of the OSM receptor Oβ. We investigated its effects on cardiomyocyte apoptosis and mitochondrial biogenesis and whether Notch3/Akt signaling was involved in the regulation of OSM-induced protection against cardiac I/R injury. The mice underwent 30 min of ischemia followed by 3 h of reperfusion and were randomized to be treated with Notch3 siRNA (siNotch3) or lentivirus carrying Notch3 cDNA (Notch3) 72 h before coronary artery ligation. Myocardial infarct size, cardiac function, cardiomyocyte apoptosis and mitochondria morphology in mice that underwent cardiac I/R injury were compared between groups. OSM alleviated cardiac I/R injury by inhibiting cardiomyocyte apoptosis through promotion of Notch3 production, thus activating the PI3K/Akt pathway. OSM enhanced mitochondrial biogenesis and mitochondrial function in mice subjected to cardiac I/R injury. In contrast, OSM receptor Oβ knock out exacerbated cardiac I/R injury, decreased Notch3 production, enhanced cardiomyocyte apoptosis, and impaired mitochondrial biogenesis in cardiac I/R injured mice. The mechanism of OSM on cardiac I/R injury is partly mediated by the Notch3/Akt pathway. These results suggest a novel role of Notch3/Akt signaling that contributes to OSM-induced protection against cardiac I/R injury.

SIRT1/PGC-1α Signaling Promotes Mitochondrial Functional Recovery and Reduces Apoptosis after Intracerebral Hemorrhage in Rats

PubMed Central

Zhou, Yang; Wang, Shaohua; Li, Yixin; Yu, Shanshan; Zhao, Yong

2018-01-01

Silent information regulator 1 (SIRT1) exerts neuroprotection in many neurodegenerative diseases. However, it is not clear if SIRT1 has protective effects after intracerebral hemorrhage (ICH)-induced brain injury in rats. Thus, our goal was to examine the influence of SIRT1 on ICH injuries and any underlying mechanisms of this influence. Brain injury was induced by autologous arterial blood (60 μL) injection into rat brains, and data show that activation of SIRT1 with SRT1720 (5 mg/kg) restored nuclear SIRT1, deacetylation of PGC-1α, and mitochondrial biogenesis and decreased mortality, behavioral deficits, and brain water content without significant changes in phosphorylated AMP-activated protein kinase (pAMPK) induced by ICH. Activation of SIRT1 with SRT1720 also restored mitochondrial electron transport chain proteins and decreased apoptotic proteins in ICH; however, these changes were reversed after ICH. In contrast, treatment with PGC-1α siRNA yielded opposite effects. To explore the protective effects of SIRT1 after ICH, siRNAs were used to knockdown SIRT1. Treatment with SIRT1 siRNA increased mortality, behavioral deficits, brain water content, mitochondrial dysfunction, and neurocyte apoptosis after ICH. Thus, activation of SIRT1 promotes recovery of mitochondrial protein and function by increasing mitochondrial biogenesis and reduces apoptosis after ICH via the PGC-1α mitochondrial pathway. These data may suggest a new therapeutic approach for ICH injuries. PMID:29375306

Ketone bodies are protective against oxidative stress in neocortical neurons.

PubMed

Kim, Do Young; Davis, Laurie M; Sullivan, Patrick G; Maalouf, Marwan; Simeone, Timothy A; van Brederode, Johannes; Rho, Jong M

2007-06-01

Ketone bodies (KB) have been shown to prevent neurodegeneration in models of Parkinson's and Alzheimer's diseases, but the mechanisms underlying these effects remain unclear. One possibility is that KB may exert antioxidant activity. In the current study, we explored the effects of KB on rat neocortical neurons exposed to hydrogen peroxide (H(2)O(2)) or diamide - a thiol oxidant and activator of mitochondrial permeability transition (mPT). We found that: (i) KB completely blocked large inward currents induced by either H(2)O(2) or diamide; (ii) KB significantly decreased the number of propidium iodide-labeled cells in neocortical slices after exposure to H(2)O(2) or diamide; (iii) KB significantly decreased reactive oxygen species (ROS) levels in dissociated neurons and in isolated neocortical mitochondria; (iv) the electrophysiological effects of KB in neurons exposed to H(2)O(2) or diamide were mimicked by bongkrekic acid and cyclosporin A, known inhibitors of mPT, as well as by catalase and DL - dithiothreitol, known antioxidants; (v) diamide alone did not significantly alter basal ROS levels in neurons, supporting previous studies indicating that diamide-induced neuronal injury may be mediated by mPT opening; and (vi) KB significantly increased the threshold for calcium-induced mPT in isolated mitochondria. Taken together, our data suggest that KB may prevent mPT and oxidative injury in neocortical neurons, most likely by decreasing mitochondrial ROS production.

Pretreatment with Resveratrol Prevents Neuronal Injury and Cognitive Deficits Induced by Perinatal Hypoxia-Ischemia in Rats

PubMed Central

Arteaga, Olatz; Revuelta, Miren; Urigüen, Leyre; Álvarez, Antonia; Montalvo, Haizea; Hilario, Enrique

2015-01-01

Despite advances in neonatal care, hypoxic-ischemic brain injury is still a serious clinical problem, which is responsible for many cases of perinatal mortality, cerebral palsy, motor impairment and cognitive deficits. Resveratrol, a natural polyphenol with important anti-oxidant and anti-inflammatory properties, is present in grapevines, peanuts and pomegranates. The aim of the present work was to evaluate the possible neuroprotective effect of resveratrol when administered before or immediately after a hypoxic-ischemic brain event in neonatal rats by analyzing brain damage, the mitochondrial status and long-term cognitive impairment. Our results indicate that pretreatment with resveratrol protects against brain damage, reducing infarct volume, preserving myelination and minimizing the astroglial reactive response. Moreover its neuroprotective effect was found to be long lasting, as behavioral outcomes were significantly improved at adulthood. We speculate that one of the mechanisms for this neuroprotection may be related to the maintenance of the mitochondrial inner membrane integrity and potential, and to the reduction of reactive oxygen species. Curiously, none of these protective features was observed when resveratrol was administered immediately after hypoxia-ischemia. PMID:26544861

Chlorogenic acid ameliorates endotoxin-induced liver injury by promoting mitochondrial oxidative phosphorylation.

PubMed

Zhou, Yan; Ruan, Zheng; Zhou, Lili; Shu, Xugang; Sun, Xiaohong; Mi, Shumei; Yang, Yuhui; Yin, Yulong

2016-01-22

Acute or chronic hepatic injury is a common pathology worldwide. Mitochondrial dysfunction and the depletion of adenosine triphosphate (ATP) play important roles in liver injury. Chlorogenic acids (CGA) are some of the most abundant phenolic acids in human diet. This study was designed to test the hypothesis that CGA may protect against chronic lipopolysaccharide (LPS)-induced liver injury by modulating mitochondrial energy generation. CGA decreased the activities of serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase. The contents of ATP and adenosine monophosphate (AMP), as well as the ratio of AMP/ATP, were increased after CGA supplementation. The activities of enzymes that are involved in glycolysis were reduced, while those of enzymes involved in oxidative phosphorylation were increased. Moreover, phosphorylated AMP-activated protein kinase (AMPK), and mRNA levels of AMPK-α, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial DNA transcription factor A were increased after CGA supplementation. Collectively, these findings suggest that the hepatoprotective effect of CGA might be associated with enhanced ATP production, the stimulation of mitochondrial oxidative phosphorylation and the inhibition of glycolysis. Copyright © 2015 Elsevier Inc. All rights reserved.

Human mesenchymal stromal cells transplanted into mice stimulate renal tubular cells and enhance mitochondrial function.

PubMed

Perico, Luca; Morigi, Marina; Rota, Cinzia; Breno, Matteo; Mele, Caterina; Noris, Marina; Introna, Martino; Capelli, Chiara; Longaretti, Lorena; Rottoli, Daniela; Conti, Sara; Corna, Daniela; Remuzzi, Giuseppe; Benigni, Ariela

2017-10-17

Mesenchymal stromal cells (MSCs) are renoprotective and drive regeneration following injury, although cellular targets of such an effect are still ill-defined. Here, we show that human umbilical cord (UC)-MSCs transplanted into mice stimulate tubular cells to regain mitochondrial mass and function, associated with enhanced microtubule-rich projections that appear to mediate mitochondrial trafficking to create a reparative dialogue among adjacent tubular cells. Treatment with UC-MSCs in mice with cisplatin-induced acute kidney injury (AKI) regulates mitochondrial biogenesis in proximal tubuli by enhancing PGC1α expression, NAD + biosynthesis and Sirtuin 3 (SIRT3) activity, thus fostering antioxidant defenses and ATP production. The functional role of SIRT3 in tubular recovery is highlighted by data that in SIRT3-deficient mice with AKI, UC-MSC treatment fails to induce renoprotection. These data document a previously unrecognized mechanism through which UC-MSCs facilitate renal repair, so as to induce global metabolic reprogramming of damaged tubular cells to sustain energy supply.Mesenchymal stromal cells drive renal regeneration following injury. Here, the authors show that human mesenchymal stromal cells, when transplanted into mice with acute kidney injury, stimulate renal tubular cell growth and enhance mitochondrial function via SIRT3.

Bnip3 mediates doxorubicin-induced cardiac myocyte necrosis and mortality through changes in mitochondrial signaling

PubMed Central

Dhingra, Rimpy; Margulets, Victoria; Chowdhury, Subir Roy; Thliveris, James; Jassal, Davinder; Fernyhough, Paul; Dorn, Gerald W.; Kirshenbaum, Lorrie A.

2014-01-01

Doxorubicin (DOX) is widely used for treating human cancers, but can induce heart failure through an undefined mechanism. Herein we describe a previously unidentified signaling pathway that couples DOX-induced mitochondrial respiratory chain defects and necrotic cell death to the BH3-only protein Bcl-2-like 19kDa-interacting protein 3 (Bnip3). Cellular defects, including vacuolization and disrupted mitochondria, were observed in DOX-treated mice hearts. This coincided with mitochondrial localization of Bnip3, increased reactive oxygen species production, loss of mitochondrial membrane potential, mitochondrial permeability transition pore opening, and necrosis. Interestingly, a 3.1-fold decrease in maximal mitochondrial respiration was observed in cardiac mitochondria of mice treated with DOX. In vehicle-treated control cells undergoing normal respiration, the respiratory chain complex IV subunit 1 (COX1) was tightly bound to uncoupling protein 3 (UCP3), but this complex was disrupted in cells treated with DOX. Mitochondrial dysfunction induced by DOX was accompanied by contractile failure and necrotic cell death. Conversely, shRNA directed against Bnip3 or a mutant of Bnip3 defective for mitochondrial targeting abrogated DOX-induced loss of COX1-UCP3 complexes and respiratory chain defects. Finally, Bnip3−/− mice treated with DOX displayed relatively normal mitochondrial morphology, respiration, and mortality rates comparable to those of saline-treated WT mice, supporting the idea that Bnip3 underlies the cardiotoxic effects of DOX. These findings reveal a new signaling pathway in which DOX-induced mitochondrial respiratory chain defects and necrotic cell death are mutually dependent on and obligatorily linked to Bnip3 gene activation. Interventions that antagonize Bnip3 may prove beneficial in preventing mitochondrial injury and heart failure in cancer patients undergoing chemotherapy. PMID:25489073

Protein kinase C-ε activation induces mitochondrial dysfunction and fragmentation in renal proximal tubules

PubMed Central

Bakajsova, Diana; Samarel, Allen M.

2011-01-01

PKC-ε activation mediates protection from ischemia-reperfusion injury in the myocardium. Mitochondria are a subcellular target of these protective mechanisms of PKC-ε. Previously, we have shown that PKC-ε activation is involved in mitochondrial dysfunction in oxidant-injured renal proximal tubular cells (RPTC; Nowak G, Bakajsova D, Clifton GL Am J Physiol Renal Physiol 286: F307–F316, 2004). The goal of this study was to examine the role of PKC-ε activation in mitochondrial dysfunction and to identify mitochondrial targets of PKC-ε in RPTC. The constitutively active and inactive mutants of PKC-ε were overexpressed in primary cultures of RPTC using the adenoviral technique. Increases in active PKC-ε levels were accompanied by PKC-ε translocation to mitochondria. Sustained PKC-ε activation resulted in decreases in state 3 respiration, electron transport rate, ATP production, ATP content, and activities of complexes I and IV and F0F1-ATPase. Furthermore, PKC-ε activation increased mitochondrial membrane potential and oxidant production and induced mitochondrial fragmentation and RPTC death. Accumulation of the dynamin-related protein in mitochondria preceded mitochondrial fragmentation. Antioxidants blocked PKC-ε-induced increases in the oxidant production but did not prevent mitochondrial fragmentation and cell death. The inactive PKC-ε mutant had no effect on mitochondrial functions, morphology, oxidant production, and RPTC viability. We conclude that active PKC-ε targets complexes I and IV and F0F1-ATPase in RPTC. PKC-ε activation mediates mitochondrial dysfunction, hyperpolarization, and fragmentation. It also induces oxidant generation and cell death, but oxidative stress is not the mechanism of RPTC death. These results show that in contrast to protective effects of PKC-ε activation in cardiomyocytes, sustained PKC-ε activation is detrimental to mitochondrial function and viability in RPTC. PMID:21289057

CGP37157, an inhibitor of the mitochondrial Na+/Ca2+ exchanger, protects neurons from excitotoxicity by blocking voltage-gated Ca2+ channels.

PubMed

Ruiz, A; Alberdi, E; Matute, C

2014-04-10

Inhibition of the mitochondrial Na(+)/Ca(2+) exchanger (NCLX) by CGP37157 is protective in models of neuronal injury that involve disruption of intracellular Ca(2+) homeostasis. However, the Ca(2+) signaling pathways and stores underlying neuroprotection by that inhibitor are not well defined. In the present study, we analyzed how intracellular Ca(2+) levels are modulated by CGP37157 (10 μM) during NMDA insults in primary cultures of rat cortical neurons. We initially assessed the presence of NCLX in mitochondria of cultured neurons by immunolabeling, and subsequently, we analyzed the effects of CGP37157 on neuronal Ca(2+) homeostasis using cameleon-based mitochondrial Ca(2+) and cytosolic Ca(2+) ([Ca(2+)]i) live imaging. We observed that NCLX-driven mitochondrial Ca(2+) exchange occurs in cortical neurons under basal conditions as CGP37157 induced a decrease in [Ca(2)]i concomitant with a Ca(2+) accumulation inside the mitochondria. In turn, CGP37157 also inhibited mitochondrial Ca(2+) efflux after the stimulation of acetylcholine receptors. In contrast, CGP37157 strongly prevented depolarization-induced [Ca(2+)]i increase by blocking voltage-gated Ca(2+) channels (VGCCs), whereas it did not induce depletion of ER Ca(2+) stores. Moreover, mitochondrial Ca(2+) overload was reduced as a consequence of diminished Ca(2+) entry through VGCCs. The decrease in cytosolic and mitochondrial Ca(2+) overload by CGP37157 resulted in a reduction of excitotoxic mitochondrial damage, characterized here by a reduction in mitochondrial membrane depolarization, oxidative stress and calpain activation. In summary, our results provide evidence that during excitotoxicity CGP37157 modulates cytosolic and mitochondrial Ca(2+) dynamics that leads to attenuation of NMDA-induced mitochondrial dysfunction and neuronal cell death by blocking VGCCs.

CGP37157, an inhibitor of the mitochondrial Na+/Ca2+ exchanger, protects neurons from excitotoxicity by blocking voltage-gated Ca2+ channels

PubMed Central

Ruiz, A; Alberdi, E; Matute, C

2014-01-01

Inhibition of the mitochondrial Na+/Ca2+ exchanger (NCLX) by CGP37157 is protective in models of neuronal injury that involve disruption of intracellular Ca2+ homeostasis. However, the Ca2+ signaling pathways and stores underlying neuroprotection by that inhibitor are not well defined. In the present study, we analyzed how intracellular Ca2+ levels are modulated by CGP37157 (10 μM) during NMDA insults in primary cultures of rat cortical neurons. We initially assessed the presence of NCLX in mitochondria of cultured neurons by immunolabeling, and subsequently, we analyzed the effects of CGP37157 on neuronal Ca2+ homeostasis using cameleon-based mitochondrial Ca2+ and cytosolic Ca2+ ([Ca2+]i) live imaging. We observed that NCLX-driven mitochondrial Ca2+ exchange occurs in cortical neurons under basal conditions as CGP37157 induced a decrease in [Ca2]i concomitant with a Ca2+ accumulation inside the mitochondria. In turn, CGP37157 also inhibited mitochondrial Ca2+ efflux after the stimulation of acetylcholine receptors. In contrast, CGP37157 strongly prevented depolarization-induced [Ca2+]i increase by blocking voltage-gated Ca2+ channels (VGCCs), whereas it did not induce depletion of ER Ca2+ stores. Moreover, mitochondrial Ca2+ overload was reduced as a consequence of diminished Ca2+ entry through VGCCs. The decrease in cytosolic and mitochondrial Ca2+ overload by CGP37157 resulted in a reduction of excitotoxic mitochondrial damage, characterized here by a reduction in mitochondrial membrane depolarization, oxidative stress and calpain activation. In summary, our results provide evidence that during excitotoxicity CGP37157 modulates cytosolic and mitochondrial Ca2+ dynamics that leads to attenuation of NMDA-induced mitochondrial dysfunction and neuronal cell death by blocking VGCCs. PMID:24722281

Chronic alcohol binging injures the liver and other organs by reducing NAD⁺ levels required for sirtuin's deacetylase activity.

PubMed

French, Samuel W

2016-04-01

NAD(+) levels are markedly reduced when blood alcohol levels are high during binge drinking. This causes liver injury to occur because the enzymes that require NAD(+) as a cofactor such as the sirtuin de-acetylases cannot de-acetylate acetylated proteins such as acetylated histones. This prevents the epigenetic changes that regulate metabolic processes and which prevent organ injury such as fatty liver in response to alcohol abuse. Hyper acetylation of numerous regulatory proteins develops. Systemic multi-organ injury occurs when NAD(+) is reduced. For instance the Circadian clock is altered if NAD(+) is not available. Cell cycle arrest occurs due to up regulation of cell cycle inhibitors leading to DNA damage, mutations, apoptosis and tumorigenesis. NAD(+) is linked to aging in the regulation of telomere stability. NAD(+) is required for mitochondrial renewal. Alcohol dehydrogenase is present in every visceral organ in the body so that there is a systemic reduction of NAD(+) levels in all of these organs during binge drinking. Copyright © 2016. Published by Elsevier Inc.

cis p-tau: early driver of brain injury and tauopathy blocked by antibody

PubMed Central

Mannix, Rebekah; Qiu, Jianhua; Moncaster, Juliet; Chen, Chun-Hau; Yao, Yandan; Lin, Yu-Min; Driver, Jane A; Sun, Yan; Wei, Shuo; Luo, Man-Li; Albayram, Onder; Huang, Pengyu; Rotenberg, Alexander; Ryo, Akihide; Goldstein, Lee E; Pascual-Leone, Alvaro; McKee, Ann C.; Meehan, William; Zhou, Xiao Zhen; Lu, Kun Ping

2015-01-01

Traumatic brain injury (TBI), characterized by acute neurological dysfunction, is one of the best known environmental risk factors for chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD), whose defining pathologic features include tauopathy made of phosphorylated tau (p-tau). However, tauopathy has not been detected in early stages after TBI and how TBI leads to tauopathy is unknown. Here we find robust cis p-tau pathology after sport- and military-related TBI in humans and mice. Acutely after TBI in mice and stress in vitro, neurons prominently produce cis p-tau, which disrupts axonal microtubule network and mitochondrial transport, spreads to other neurons, and leads to apoptosis. This process, termed “cistauosis”, appears long before other tauopathy. Treating TBI mice with cis antibody blocks cistauosis, prevents tauopathy development and spread, and restores many TBI-related structural and functional sequelae. Thus, cis p-tau is a major early driver after TBI and leads to tauopathy in CTE and AD, and cis antibody may be further developed to detect and treat TBI, and prevent progressive neurodegeneration after injury. PMID:26176913

Autophagy and skeletal muscles in sepsis.

PubMed

Mofarrahi, Mahroo; Sigala, Ioanna; Guo, Yeting; Godin, Richard; Davis, Elaine C; Petrof, Basil; Sandri, Marco; Burelle, Yan; Hussain, Sabah N A

2012-01-01

Mitochondrial injury develops in skeletal muscles during the course of severe sepsis. Autophagy is a protein and organelle recycling pathway which functions to degrade or recycle unnecessary, redundant, or inefficient cellular components. No information is available regarding the degree of sepsis-induced mitochondrial injury and autophagy in the ventilatory and locomotor muscles. This study tests the hypotheses that the locomotor muscles are more prone to sepsis-induced mitochondrial injury, depressed biogenesis and autophagy induction compared with the ventilatory muscles. Adult male C57/Bl6 mice were injected with i.p. phosphate buffered saline (PBS) or E. coli lipopolysaccharide (LPS, 20 mg/kg) and sacrificed 24 h later. The tibialis anterior (TA), soleus (SOLD) and diaphragm (DIA) muscles were quickly excised and examined for mitochondrial morphological injury, Ca(++) retention capacity and biogenesis. Autophagy was detected with electron microscopy, lipidation of Lc3b proteins and by measuring gene expression of several autophagy-related genes. Electron microscopy revealed ultrastructural injuries in the mitochondria of each muscle, however, injuries were more severe in the TA and SOL muscles than they were in the DIA. Gene expressions of nuclear and mitochondrial DNA transcription factors and co-activators (indicators of biogenesis) were significantly depressed in all treated muscles, although to a greater extent in the TA and SOL muscles. Significant autophagosome formation, Lc3b protein lipidation and upregulation of autophagy-related proteins were detected to a greater extent in the TA and SOL muscles and less so in the DIA. Lipidation of Lc3b and the degree of induction of autophagy-related proteins were significantly blunted in mice expressing a muscle-specific IκBα superrepresor. We conclude that locomotor muscles are more prone to sepsis-induced mitochondrial injury, decreased biogenesis and increased autophagy compared with the ventilatory muscles and that autophagy in skeletal muscles during sepsis is regulated in part through the NFκB transcription factor.

Autophagy and Skeletal Muscles in Sepsis

PubMed Central

Mofarrahi, Mahroo; Sigala, Ioanna; Guo, Yeting; Godin, Richard; Davis, Elaine C.; Petrof, Basil; Sandri, Marco

2012-01-01

Background Mitochondrial injury develops in skeletal muscles during the course of severe sepsis. Autophagy is a protein and organelle recycling pathway which functions to degrade or recycle unnecessary, redundant, or inefficient cellular components. No information is available regarding the degree of sepsis-induced mitochondrial injury and autophagy in the ventilatory and locomotor muscles. This study tests the hypotheses that the locomotor muscles are more prone to sepsis-induced mitochondrial injury, depressed biogenesis and autophagy induction compared with the ventilatory muscles. Methodology/Principal Findings Adult male C57/Bl6 mice were injected with i.p. phosphate buffered saline (PBS) or E. coli lipopolysaccharide (LPS, 20 mg/kg) and sacrificed 24 h later. The tibialis anterior (TA), soleus (SOLD) and diaphragm (DIA) muscles were quickly excised and examined for mitochondrial morphological injury, Ca++ retention capacity and biogenesis. Autophagy was detected with electron microscopy, lipidation of Lc3b proteins and by measuring gene expression of several autophagy-related genes. Electron microscopy revealed ultrastructural injuries in the mitochondria of each muscle, however, injuries were more severe in the TA and SOL muscles than they were in the DIA. Gene expressions of nuclear and mitochondrial DNA transcription factors and co-activators (indicators of biogenesis) were significantly depressed in all treated muscles, although to a greater extent in the TA and SOL muscles. Significant autophagosome formation, Lc3b protein lipidation and upregulation of autophagy-related proteins were detected to a greater extent in the TA and SOL muscles and less so in the DIA. Lipidation of Lc3b and the degree of induction of autophagy-related proteins were significantly blunted in mice expressing a muscle-specific IκBα superrepresor. Conclusion/Significance We conclude that locomotor muscles are more prone to sepsis-induced mitochondrial injury, decreased biogenesis and increased autophagy compared with the ventilatory muscles and that autophagy in skeletal muscles during sepsis is regulated in part through the NFκB transcription factor. PMID:23056618

Redox proteomic identification of HNE-bound mitochondrial proteins in cardiac tissues reveals a systemic effect on energy metabolism after doxorubicin treatment.

PubMed

Zhao, Y; Miriyala, S; Miao, L; Mitov, M; Schnell, D; Dhar, S K; Cai, J; Klein, J B; Sultana, R; Butterfield, D A; Vore, M; Batinic-Haberle, I; Bondada, S; St Clair, D K

2014-07-01

Doxorubicin (DOX), one of the most effective anticancer drugs, is known to generate progressive cardiac damage, which is due, in part, to DOX-induced reactive oxygen species (ROS). The elevated ROS often induce oxidative protein modifications that result in alteration of protein functions. This study demonstrates that the level of proteins adducted by 4-hydroxy-2-nonenal (HNE), a lipid peroxidation product, is significantly increased in mouse heart mitochondria after DOX treatment. A redox proteomics method involving two-dimensional electrophoresis followed by mass spectrometry and investigation of protein databases identified several HNE-modified mitochondrial proteins, which were verified by HNE-specific immunoprecipitation in cardiac mitochondria from the DOX-treated mice. The majority of the identified proteins are related to mitochondrial energy metabolism. These include proteins in the citric acid cycle and electron transport chain. The enzymatic activities of the HNE-adducted proteins were significantly reduced in DOX-treated mice. Consistent with the decline in the function of the HNE-adducted proteins, the respiratory function of cardiac mitochondria as determined by oxygen consumption rate was also significantly reduced after DOX treatment. Treatment with Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin, an SOD mimic, averted the doxorubicin-induced mitochondrial dysfunctions as well as the HNE-protein adductions. Together, the results demonstrate that free radical-mediated alteration of energy metabolism is an important mechanism mediating DOX-induced cardiac injury, suggesting that metabolic intervention may represent a novel approach to preventing cardiac injury after chemotherapy. Copyright © 2014 Elsevier Inc. All rights reserved.

Bacopa monnieri-Induced Protective Autophagy Inhibits Benzo[a]pyrene-Mediated Apoptosis.

PubMed

Das, Durgesh Nandini; Naik, Prajna Paramita; Nayak, Aditi; Panda, Prashanta Kumar; Mukhopadhyay, Subhadip; Sinha, Niharika; Bhutia, Sujit K

2016-11-01

Benzo[a]pyrene (B[a]P) is capable of inducing oxidative stress and cellular injuries leading to cell death and associates with a significant risk of cancer development. Prevention of B[a]P-induced cellular toxicity with herbal compound through regulation of mitochondrial oxidative stress might protect cell death and have therapeutic benefit to human health. In this study, we demonstrated the cytoprotective role of Bacopa monnieri (BM) against B[a]P-induced apoptosis through autophagy induction. Pretreatment with BM rescued the reduction in cell viability in B[a]P-treated human keratinocytes (HaCaT) cells indicating the cytoprotective potential of BM against B[a]P. Moreover, BM was found to inhibit B[a]P-mediated reactive oxygen species (ROS)-induced apoptosis activation in HaCaT cells. Furthermore, BM was found to preserve mitochondrial membrane potential and inhibited release of cytochrome c in B[a]P-treated HaCaT cells. Bacopa monnieri induced protective autophagy; we knocked down Beclin-1, and data showed that BM was unable to protect from B[a]P-induced mitochondrial ROS-mediated apoptosis in Beclin-1-deficient HaCaT cells. Moreover, we established that B[a]P-induced damaged mitochondria were found to colocalize and degraded within autolysosomes in order to protect HaCaT cells from mitochondrial injury. In conclusion, B[a]P-induced apoptosis was rescued by BM treatment and provided cytoprotection through Beclin-1-dependent autophagy activation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Long-term treatment with a Yang-invigorating Chinese herbal formula produces generalized tissue protection against oxidative damage in rats.

PubMed

Chiu, Po Yee; Leung, Hoi Yan; Siu, Ada Hoi Ling; Chen, Na; Poon, Michel K T; Ko, Kam Ming

2008-02-01

Previous work in our laboratory has shown that long-term treatment with Vigconic 28 (VI-28), a Yang-invigorating Chinese herbal formula used for the promotion of overall wellness in Chinese medicine, can enhance the mitochondrial functional ability and antioxidant capacity in various tissues of both male and female rats. To investigate whether the VI-28 treatment regimen could afford tissue protection against oxidative injury, the effects of long-term VI-28 treatment (80 or 240 mg/kg/d x 30) on oxidative stress-induced tissue damage in various organs (brain, heart, liver, and kidney) were examined in female rats. The results indicated that long-term VI-28 treatment invariably protected against oxidative tissue damage in the rat models of cerebral/myocardial ischemia-reperfusion injury, CCl4 hepatotoxicity, and gentamicin nephrotoxicity. The tissue protection was associated with increases in the levels and activities of mitochondrial antioxidant components as well as with the preservation of mitochondrial structural integrity. This was evidenced by decreases in the sensitivity of mitochondria to Ca2+-induced permeability transition, and in the levels of mitochondrial malondialdehyde production, Ca2+ loading, and cytochrome c release in the tissues examined. Interestingly, the VI-28 treatment increased red cell CuZn-superoxide dismutase (CuZn-SOD) levels, and these levels correlated positively with the degree of tissue protection afforded by long-term VI-28 treatment in rats. The generalized tissue protection afforded by long-term VI-28 treatment may have clinical implications in the prevention of age-related diseases, and VI-28 treatment may possibly delay the aging process.

Hydrogen Sulfide Protects Renal Grafts Against Prolonged Cold Ischemia-Reperfusion Injury via Specific Mitochondrial Actions.

PubMed

Lobb, I; Jiang, J; Lian, D; Liu, W; Haig, A; Saha, M N; Torregrossa, R; Wood, M E; Whiteman, M; Sener, A

2017-02-01

Ischemia-reperfusion injury is unavoidably caused by loss and subsequent restoration of blood flow during organ procurement, and prolonged ischemia-reperfusion injury IRI results in increased rates of delayed graft function and early graft loss. The endogenously produced gasotransmitter, hydrogen sulfide (H 2 S), is a novel molecule that mitigates hypoxic tissue injury. The current study investigates the protective mitochondrial effects of H 2 S during in vivo cold storage and subsequent renal transplantation (RTx) and in vitro cold hypoxic renal injury. Donor allografts from Brown Norway rats treated with University of Wisconsin (UW) solution + H 2 S (150 μM NaSH) during prolonged (24-h) cold (4°C) storage exhibited significantly (p < 0.05) decreased acute necrotic/apoptotic injury and significantly (p < 0.05) improved function and recipient Lewis rat survival compared to UW solution alone. Treatment of rat kidney epithelial cells (NRK-52E) with the mitochondrial-targeted H 2 S donor, AP39, during in vitro cold hypoxic injury improved the protective capacity of H 2 S >1000-fold compared to similar levels of the nonspecific H 2 S donor, GYY4137 and also improved syngraft function and survival following prolonged cold storage compared to UW solution. H 2 S treatment mitigates cold IRI-associated renal injury via mitochondrial actions and could represent a novel therapeutic strategy to minimize the detrimental clinical outcomes of prolonged cold IRI during RTx. © 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.

Impaired cortical mitochondrial function following TBI precedes behavioral changes

PubMed Central

Watson, William D.; Buonora, John E.; Yarnell, Angela M.; Lucky, Jessica J.; D’Acchille, Michaela I.; McMullen, David C.; Boston, Andrew G.; Kuczmarski, Andrew V.; Kean, William S.; Verma, Ajay; Grunberg, Neil E.; Cole, Jeffrey T.

2014-01-01

Traumatic brain injury (TBI) pathophysiology can be attributed to either the immediate, primary physical injury, or the delayed, secondary injury which begins minutes to hours after the initial injury and can persist for several months or longer. Because these secondary cascades are delayed and last for a significant time period post-TBI, they are primary research targets for new therapeutics. To investigate changes in mitochondrial function after a brain injury, both the cortical impact site and ipsilateral hippocampus of adult male rats 7 and 17 days after a controlled cortical impact (CCI) injury were examined. State 3, state 4, and uncoupler-stimulated rates of oxygen consumption, respiratory control ratios (RCRs) were measured and membrane potential quantified, and all were significantly decreased in 7 day post-TBI cortical mitochondria. By contrast, hippocampal mitochondria at 7 days showed only non-significant decreases in rates of oxygen consumption and membrane potential. NADH oxidase activities measured in disrupted mitochondria were normal in both injured cortex and hippocampus at 7 days post-CCI. Respiratory and phosphorylation capacities at 17 days post-CCI were comparable to naïve animals for both cortical and hippocampus mitochondria. However, unlike oxidative phosphorylation, membrane potential of mitochondria in the cortical lining of the impact site did not recover at 17 days, suggesting that while diminished cortical membrane potential at 17 days does not adversely affect mitochondrial capacity to synthesize ATP, it may negatively impact other membrane potential-sensitive mitochondrial functions. Memory status, as assessed by a passive avoidance paradigm, was not significantly impaired until 17 days after injury. These results indicate pronounced disturbances in cortical mitochondrial function 7 days after CCI which precede the behavioral impairment observed at 17 days. PMID:24550822

The mitochondria-targeted anti-oxidant MitoQ decreases ischemia-reperfusion injury in a murine syngeneic heart transplant model.

PubMed

Dare, Anna J; Logan, Angela; Prime, Tracy A; Rogatti, Sebastian; Goddard, Martin; Bolton, Eleanor M; Bradley, J Andrew; Pettigrew, Gavin J; Murphy, Michael P; Saeb-Parsy, Kourosh

2015-11-01

Free radical production and mitochondrial dysfunction during cardiac graft reperfusion is a major factor in post-transplant ischemia-reperfusion (IR) injury, an important underlying cause of primary graft dysfunction. We therefore assessed the efficacy of the mitochondria-targeted anti-oxidant MitoQ in reducing IR injury in a murine heterotopic cardiac transplant model. Hearts from C57BL/6 donor mice were flushed with storage solution alone, solution containing the anti-oxidant MitoQ, or solution containing the non-anti-oxidant decyltriphenylphosphonium control and exposed to short (30 minutes) or prolonged (4 hour) cold preservation before transplantation. Grafts were transplanted into C57BL/6 recipients and analyzed for mitochondrial reactive oxygen species production, oxidative damage, serum troponin, beating score, and inflammatory markers 120 minutes or 24 hours post-transplant. MitoQ was taken up by the heart during cold storage. Prolonged cold preservation of donor hearts before IR increased IR injury (troponin I, beating score) and mitochondrial reactive oxygen species, mitochondrial DNA damage, protein carbonyls, and pro-inflammatory cytokine release 24 hours after transplant. Administration of MitoQ to the donor heart in the storage solution protected against this IR injury by blocking graft oxidative damage and dampening the early pro-inflammatory response in the recipient. IR after heart transplantation results in mitochondrial oxidative damage that is potentiated by cold ischemia. Supplementing donor graft perfusion with the anti-oxidant MitoQ before transplantation should be studied further to reduce IR-related free radical production, the innate immune response to IR injury, and subsequent donor cardiac injury. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

The mitochondria-targeted anti-oxidant MitoQ decreases ischemia-reperfusion injury in a murine syngeneic heart transplant model

PubMed Central

Dare, Anna J.; Logan, Angela; Prime, Tracy A.; Rogatti, Sebastian; Goddard, Martin; Bolton, Eleanor M.; Bradley, J. Andrew; Pettigrew, Gavin J.; Murphy, Michael P.; Saeb-Parsy, Kourosh

2015-01-01

Background Free radical production and mitochondrial dysfunction during cardiac graft reperfusion is a major factor in post-transplant ischemia-reperfusion (IR) injury, an important underlying cause of primary graft dysfunction. We therefore assessed the efficacy of the mitochondria-targeted anti-oxidant MitoQ in reducing IR injury in a murine heterotopic cardiac transplant model. Methods Hearts from C57BL/6 donor mice were flushed with storage solution alone, solution containing the anti-oxidant MitoQ, or solution containing the non–anti-oxidant decyltriphenylphosphonium control and exposed to short (30 minutes) or prolonged (4 hour) cold preservation before transplantation. Grafts were transplanted into C57BL/6 recipients and analyzed for mitochondrial reactive oxygen species production, oxidative damage, serum troponin, beating score, and inflammatory markers 120 minutes or 24 hours post-transplant. Results MitoQ was taken up by the heart during cold storage. Prolonged cold preservation of donor hearts before IR increased IR injury (troponin I, beating score) and mitochondrial reactive oxygen species, mitochondrial DNA damage, protein carbonyls, and pro-inflammatory cytokine release 24 hours after transplant. Administration of MitoQ to the donor heart in the storage solution protected against this IR injury by blocking graft oxidative damage and dampening the early pro-inflammatory response in the recipient. Conclusions IR after heart transplantation results in mitochondrial oxidative damage that is potentiated by cold ischemia. Supplementing donor graft perfusion with the anti-oxidant MitoQ before transplantation should be studied further to reduce IR-related free radical production, the innate immune response to IR injury, and subsequent donor cardiac injury. PMID:26140808

EGCG protects against homocysteine-induced human umbilical vein endothelial cells apoptosis by modulating mitochondrial-dependent apoptotic signaling and PI3K/Akt/eNOS signaling pathways.

PubMed

Liu, Shumin; Sun, Zhengwu; Chu, Peng; Li, Hailong; Ahsan, Anil; Zhou, Ziru; Zhang, Zonghui; Sun, Bin; Wu, Jingjun; Xi, Yalin; Han, Guozhu; Lin, Yuan; Peng, Jinyong; Tang, Zeyao

2017-05-01

Homocysteine (Hcy) induced vascular endothelial injury leads to the progression of endothelial dysfunction in atherosclerosis. Epigallocatechin gallate (EGCG), a natural dietary antioxidant, has been applied to protect against atherosclerosis. However, the underlying protective mechanism of EGCG has not been clarified. The present study investigated the mechanism of EGCG protected against Hcy-induced human umbilical vein endothelial cells (HUVECs) apoptosis. Methyl thiazolyl tetrazolium assay (MTT), transmission electron microscope, fluorescent staining, flow cytometry, western blot were used in this study. The study has demonstrated that EGCG suppressed Hcy-induced endothelial cell morphological changes and reactive oxygen species (ROS) generation. Moreover, EGCG dose-dependently prevented Hcy-induced HUVECs cytotoxicity and apoptotic biochemical changes such as reducing mitochondrial membrane potential (MMP), decreasing Bcl-2/Bax protein ratio and activating caspase-9 and 3. In addition, EGCG enhanced the protein ratio of p-Akt/Akt, endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) formation in injured cells. In conclusion, the present study shows that EGCG prevents Hcy-induced HUVECs apoptosis via modulating mitochondrial apoptotic and PI3K/Akt/eNOS signaling pathways. Furthermore, the results indicate that EGCG is likely to represent a potential therapeutic strategy for atherosclerosis associated with Hyperhomocysteinemia (HHcy).

Isolating the segment of the mitochondrial electron transport chain responsible for mitochondrial damage during cardiac ischemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Qun; Yin, Guotian; Stewart, Sarah

2010-07-09

Ischemia damages the mitochondrial electron transport chain (ETC), mediated in part by damage generated by the mitochondria themselves. Mitochondrial damage resulting from ischemia, in turn, leads to cardiac injury during reperfusion. The goal of the present study was to localize the segment of the ETC that produces the ischemic mitochondrial damage. We tested if blockade of the proximal ETC at complex I differed from blockade distal in the chain at cytochrome oxidase. Isolated rabbit hearts were perfused for 15 min followed by 30 min stop-flow ischemia at 37 {sup o}C. Amobarbital (2.5 mM) or azide (5 mM) was used tomore » block proximal (complex I) or distal (cytochrome oxidase) sites in the ETC. Time control hearts were buffer-perfused for 45 min. Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) were isolated. Ischemia decreased cytochrome c content in SSM but not in IFM compared to time control. Blockade of electron transport at complex I preserved the cytochrome c content in SSM. In contrast, blockade of electron transport at cytochrome oxidase with azide did not retain cytochrome c in SSM during ischemia. Since blockade of electron transport at complex III also prevented cytochrome c loss during ischemia, the specific site that elicits mitochondrial damage during ischemia is likely located in the segment between complex III and cytochrome oxidase.« less

N-acetylcysteine with apocynin prevents hyperoxaluria-induced mitochondrial protein perturbations in nephrolithiasis.

PubMed

Sharma, Minu; Sud, Amit; Kaur, Tanzeer; Tandon, Chanderdeep; Singla, S K

2016-09-01

Diminished mitochondrial activities were deemed to play an imperative role in surged oxidative damage perceived in hyperoxaluric renal tissue. Proteomics is particularly valuable to delineate the damaging effects of oxidative stress on mitochondrial proteins. The present study was designed to apply large-scale proteomics to describe systematically how mitochondrial proteins/pathways govern the renal damage and calcium oxalate crystal adhesion in hyperoxaluria. Furthermore, the potential beneficial effects of combinatorial therapy with N-acetylcysteine (NAC) and apocynin were studied to establish its credibility in the modulation of hyperoxaluria-induced alterations in mitochondrial proteins. In an experimental setup with male Wistar rats, five groups were designed for 9 d. At the end of the experiment, 24-h urine was collected and rats were euthanized. Urinary samples were analyzed for kidney injury marker and creatinine clearance. Transmission electron microscopy revealed distorted renal mitochondria in hyperoxaluria but combinatorial therapy restored the normal mitochondrial architecture. Mitochondria were isolated from renal tissue of experimental rats, and mitochondrial membrane potential was analyzed. The two-dimensional electrophoresis (2-DE) based comparative proteomic analysis was performed on proteins isolated from renal mitochondria. The results revealed eight differentially expressed mitochondrial proteins in hyperoxaluric rats, which were identified by Matrix-assisted laser desorption/ionization time of flight/time of flight (MALDI-TOF/TOF) analysis. Identified proteins including those involved in important mitochondrial processes, e.g. antioxidant defense, energy metabolism, and electron transport chain. Therapeutic administration of NAC with apocynin significantly expunged hyperoxaluria-induced discrepancy in the renal mitochondrial proteins, bringing them closer to the controls. The results provide insights to further understand the underlying mechanisms in the development of hyperoxaluria-induced nephrolithiasis and the therapeutic relevance of the combinatorial therapy.

Abnormal permeability of inner and outer mitochondrial membranes contributes independently to mitochondrial dysfunction in the liver during acute endotoxemia.

PubMed

Crouser, Elliott D; Julian, Mark W; Huff, Jennifer E; Joshi, Mandar S; Bauer, John A; Gadd, Martha E; Wewers, Mark D; Pfeiffer, Douglas R

2004-02-01

This study was designed to determine the role played by the mitochondrial permeability transition in the pathogenesis of mitochondrial damage and dysfunction in a representative systemic organ during the acute phase of endotoxemia. A well-established, normotensive feline model was employed to determine whether pretreatment with cyclosporine A, a potent inhibitor of the mitochondrial permeability transition, normalizes mitochondrial ultrastructural injury and dysfunction in the liver during acute endotoxemia. The Ohio State University Medical Center research laboratory. Random source, adult, male conditioned cats. Hemodynamic resuscitation and maintenance of acid-base balance and tissue oxygen availability were provided, as needed, to minimize the potentially confounding effects of tissue hypoxia and/or acidosis on the experimental results. Treatment groups received isotonic saline vehicle (control; n = 6), lipopolysaccharide (3.0 mg/kg, intravenously; n = 8), or cyclosporine A (6.0 mg/kg, intravenously; n = 6) or tacrolimus (FK506, 0.1 mg/kg, intravenously; n = 4) followed in 30 mins by lipopolysaccharide (3.0 mg/kg, intravenously). Liver samples were obtained 4 hrs posttreatment, and mitochondrial ultrastructure, function, and cytochrome c, Bax, and ceramide contents were assessed. As expected, significant mitochondrial injury was apparent in the liver 4 hrs after lipopolysaccharide treatment, despite maintenance of regional tissue oxygen availability. Namely, mitochondria demonstrated high-amplitude swelling and exhibited altered respiratory function. Cyclosporine A pretreatment attenuated lipopolysaccharide-induced mitochondrial ultrastructural abnormalities and normalized mitochondrial respiratory control, reflecting protection against inner mitochondrial membrane damage. However, an abnormal permeability of outer mitochondrial membranes to cytochrome c was observed in all lipopolysaccharide-treated groups and was associated with increased mitochondrial concentrations of Bax and ceramide. These studies confirm that liver mitochondria are early targets of injury during endotoxemia and that inner and outer mitochondrial membrane damage occurs through different mechanisms. Inner mitochondrial membrane damage appears to relate to the mitochondrial permeability transition, whereas outer mitochondrial membrane damage can occur independent of the mitochondrial permeability transition. Preliminary evidence suggests that Bax may participate in lipopolysaccharide-induced outer mitochondrial membrane damage, but further investigations are needed to confirm this.

Cholecystokinin induces caspase activation and mitochondrial dysfunction in pancreatic acinar cells. Roles in cell injury processes of pancreatitis.

PubMed

Gukovskaya, Anna S; Gukovsky, Ilya; Jung, Yoon; Mouria, Michelle; Pandol, Stephen J

2002-06-21

Apoptosis and necrosis are critical parameters of pancreatitis, the mechanisms of which remain unknown. Many characteristics of pancreatitis can be studied in vitro in pancreatic acini treated with high doses of cholecystokinin (CCK). We show here that CCK stimulates apoptosis and death signaling pathways in rat pancreatic acinar cells, including caspase activation, cytochrome c release, and mitochondrial depolarization. The mitochondrial dysfunction is mediated by upstream caspases (possibly caspase-8) and, in turn, leads to activation of caspase-3. CCK causes mitochondrial alterations through both permeability transition pore-dependent (cytochrome c release) and permeability transition pore-independent (mitochondrial depolarization) mechanisms. Caspase activation and mitochondrial alterations also occur in untreated pancreatic acinar cells; however, the underlying mechanisms are different. In particular, caspases protect untreated acinar cells from mitochondrial damage. We found that caspases not only mediate apoptosis but also regulate other parameters of CCK-induced acinar cell injury that are characteristic of pancreatitis; in particular, caspases negatively regulate necrosis and trypsin activation in acinar cells. The results suggest that the observed signaling pathways regulate parenchymal cell injury and death in CCK-induced pancreatitis. Protection against necrosis and trypsin activation by caspases can explain why the severity of pancreatitis in experimental models correlates inversely with the extent of apoptosis.

Mitochondrial respiratory chain complexes as sources and targets of thiol-based redox-regulation.

PubMed

Dröse, Stefan; Brandt, Ulrich; Wittig, Ilka

2014-08-01

The respiratory chain of the inner mitochondrial membrane is a unique assembly of protein complexes that transfers the electrons of reducing equivalents extracted from foodstuff to molecular oxygen to generate a proton-motive force as the primary energy source for cellular ATP-synthesis. Recent evidence indicates that redox reactions are also involved in regulating mitochondrial function via redox-modification of specific cysteine-thiol groups in subunits of respiratory chain complexes. Vice versa the generation of reactive oxygen species (ROS) by respiratory chain complexes may have an impact on the mitochondrial redox balance through reversible and irreversible thiol-modification of specific target proteins involved in redox signaling, but also pathophysiological processes. Recent evidence indicates that thiol-based redox regulation of the respiratory chain activity and especially S-nitrosylation of complex I could be a strategy to prevent elevated ROS production, oxidative damage and tissue necrosis during ischemia-reperfusion injury. This review focuses on the thiol-based redox processes involving the respiratory chain as a source as well as a target, including a general overview on mitochondria as highly compartmentalized redox organelles and on methods to investigate the redox state of mitochondrial proteins. This article is part of a Special Issue entitled: Thiol-Based Redox Processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Interactive HIV-1 Tat and morphine-induced synaptodendritic injury is triggered through focal disruptions in Na⁺ influx, mitochondrial instability, and Ca²⁺ overload.

PubMed

Fitting, Sylvia; Knapp, Pamela E; Zou, Shiping; Marks, William D; Bowers, M Scott; Akbarali, Hamid I; Hauser, Kurt F

2014-09-17

Synaptodendritic injury is thought to underlie HIV-associated neurocognitive disorders and contributes to exaggerated inflammation and cognitive impairment seen in opioid abusers with HIV-1. To examine events triggering combined transactivator of transcription (Tat)- and morphine-induced synaptodendritic injury systematically, striatal neuron imaging studies were conducted in vitro. These studies demonstrated nearly identical pathologic increases in dendritic varicosities as seen in Tat transgenic mice in vivo. Tat caused significant focal increases in intracellular sodium ([Na(+)]i) and calcium ([Ca(2+)]i) in dendrites that were accompanied by the emergence of dendritic varicosities. These effects were largely, but not entirely, attenuated by the NMDA and AMPA receptor antagonists MK-801 and CNQX, respectively. Concurrent morphine treatment accelerated Tat-induced focal varicosities, which were accompanied by localized increases in [Ca(2+)]i and exaggerated instability in mitochondrial inner membrane potential. Importantly, morphine's effects were prevented by the μ-opioid receptor antagonist CTAP and were not observed in neurons cultured from μ-opioid receptor knock-out mice. Combined Tat- and morphine-induced initial losses in ion homeostasis and increases in [Ca(2+)]i were attenuated by the ryanodine receptor inhibitor ryanodine, as well as pyruvate. In summary, Tat induced increases in [Na(+)]i, mitochondrial instability, excessive Ca(2+) influx through glutamatergic receptors, and swelling along dendrites. Morphine, acting via μ-opioid receptors, exacerbates these excitotoxic Tat effects at the same subcellular locations by mobilizing additional [Ca(2+)]i and by further disrupting [Ca(2+)]i homeostasis. We hypothesize that the spatiotemporal relationship of μ-opioid and aberrant AMPA/NMDA glutamate receptor signaling is critical in defining the location and degree to which opiates exacerbate the synaptodendritic injury commonly observed in neuroAIDS. Copyright © 2014 the authors 0270-6474/14/3412850-15$15.00/0.

Mitochondrial PKC-ε deficiency promotes I/R-mediated myocardial injury via GSK3β-dependent mitochondrial permeability transition pore opening.

PubMed

Wang, Shijun; Zhang, Feng; Zhao, Gang; Cheng, Yong; Wu, Ting; Wu, Bing; Zhang, You-En

2017-09-01

Mitochondrial fission is critically involved in cardiomyocyte apoptosis, which has been considered as one of the leading causes of ischaemia/reperfusion (I/R)-induced myocardial injury. In our previous works, we demonstrate that aldehyde dehydrogenase-2 (ALDH2) deficiency aggravates cardiomyocyte apoptosis and cardiac dysfunction. The aim of this study was to elucidate whether ALDH2 deficiency promotes mitochondrial injury and cardiomyocyte death in response to I/R stress and the underlying mechanism. I/R injury was induced by aortic cross-clamping for 45 min. followed by unclamping for 24 hrs in ALDH2 knockout (ALDH2 -/- ) and wild-type (WT) mice. Then myocardial infarct size, cell apoptosis and cardiac function were examined. The protein kinase C (PKC) isoform expressions and their mitochondrial translocation, the activity of dynamin-related protein 1 (Drp1), caspase9 and caspase3 were determined by Western blot. The effects of N-acetylcysteine (NAC) or PKC-δ shRNA treatment on glycogen synthase kinase-3β (GSK-3β) activity and mitochondrial permeability transition pore (mPTP) opening were also detected. The results showed that ALDH2 -/- mice exhibited increased myocardial infarct size and cardiomyocyte apoptosis, enhanced levels of cleaved caspase9, caspase3 and phosphorylated Drp1. Mitochondrial PKC-ε translocation was lower in ALDH2 -/- mice than in WT mice, and PKC-δ was the opposite. Further data showed that mitochondrial PKC isoform ratio was regulated by cellular reactive oxygen species (ROS) level, which could be reversed by NAC pre-treatment under I/R injury. In addition, PKC-ε inhibition caused activation of caspase9, caspase3 and Drp1Ser 616 in response to I/R stress. Importantly, expression of phosphorylated GSK-3β (inactive form) was lower in ALDH2 -/- mice than in WT mice, and both were increased by NAC pre-treatment. I/R-induced mitochondrial translocation of GSK-3β was inhibited by PKC-δ shRNA or NAC pre-treatment. In addition, mitochondrial membrane potential (∆Ψ m ) was reduced in ALDH2 -/- mice after I/R, which was partly reversed by the GSK-3β inhibitor (SB216763) or PKC-δ shRNA. Collectively, our data provide the evidence that abnormal PKC-ε/PKC-δ ratio promotes the activation of Drp1 signalling, caspase cascades and GSK-3β-dependent mPTP opening, which results in mitochondrial injury-triggered cardiomyocyte apoptosis and myocardial dysfuction in ALDH2 -/- mice following I/R stress. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Indian Ginseng (Withania somnifera) supplementation ameliorates oxidative stress and mitochondrial dysfunctions in experimental model of stroke.

PubMed

Sood, Abhilasha; Mehrotra, Arpit; Dhawan, Devinder K; Sandhir, Rajat

2018-04-18

Stroke is an increasingly prevalent clinical condition and second leading cause of death globally. The present study evaluated the therapeutic potential of Indian Ginseng, also known as Withania somnifera (WS), supplementation on middle cerebral artery occlusion (MCAO) induced mitochondrial dysfunctions in experimental model of ischemic stroke. Stroke was induced in animals by occluding the middle cerebral artery, followed by reperfusion injury. Ischemia reperfusion injury resulted in increased oxidative stress indicated by increased reactive oxygen species and protein carbonyl levels; compromised antioxidant system; in terms of reduced superoxide dismutase and catalase activity, along with reduction in GSH levels and the redox ratio, impaired mitochondrial functions and enhanced expression of apoptosis markers. Ischemia reperfusion injury induced mitochondrial dysfunctions in terms of (i) reduced activity of the mitochondrial respiratory chain enzymes, (ii) reduced histochemical staining of complex-II and IV, (iii) reduced in-gel activity of mitochondrial complex-I to V, (iv) mitochondrial structural changes in terms of increased mitochondrial swelling, reduced mitochondrial membrane potential and ultrastructural changes. Additionally, an increase in the activity of caspase-3 and caspase-9 was also observed, along with altered expression of apoptotic proteins Bcl-2 and Bax in MCAO animals. MCAO animals also showed significant impairment in cognitive functions assessed using Y maze test. WS pre-supplementation, on the other hand ameliorated MCAO induced oxidative stress, mitochondrial dysfunctions, apoptosis and cognitive impairments. The results show protective effect of WS pre-supplementation in ischemic stroke and are suggestive of its potential application in stroke management.

Lansoprazole protects and heals gastric mucosa from non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy by inhibiting mitochondrial as well as Fas-mediated death pathways with concurrent induction of mucosal cell renewal.

PubMed

Maity, Pallab; Bindu, Samik; Choubey, Vinay; Alam, Athar; Mitra, Kalyan; Goyal, Manish; Dey, Sumanta; Guha, Mithu; Pal, Chinmay; Bandyopadhyay, Uday

2008-05-23

We have investigated the mechanism of antiapoptotic and cell renewal effects of lansoprazole, a proton pump inhibitor, to protect and heal gastric mucosal injury in vivo induced by indomethacin, a non-steroidal anti-inflammatory drug (NSAID). Lansoprazole prevents indomethacin-induced gastric damage by blocking activation of mitochondrial and Fas pathways of apoptosis. Lansoprazole prevents indomethacin-induced up-regulation of proapoptotic Bax and Bak and down-regulation of antiapoptotic Bcl-2 and Bcl(xL) to maintain the normal proapoptotic/antiapoptotic ratio and thereby arrests indomethacin-induced mitochondrial translocation of Bax and collapse of mitochondrial membrane potential followed by cytochrome c release and caspase-9 activation. Lansoprazole also inhibits indomethacin-induced Fas-mediated mucosal cell death by down-regulating Fas or FasL expression and inhibiting caspase-8 activation. Lansoprazole favors mucosal cell renewal simultaneously by stimulating gene expression of prosurvival proliferating cell nuclear antigen, survivin, epidermal growth factor, and basic fibroblast growth factor. The up-regulation of Flt-1 further indicates that lansoprazole activates vascular epidermal growth factor-mediated controlled angiogenesis to repair gastric mucosa. Lansoprazole also stimulates the healing of already formed ulcers induced by indomethacin. Time course study of healing indicates that it switches off the mitochondrial death pathway completely but not the Fas pathway. However, lansoprazole heals mucosal lesions almost completely after overcoming the persisting Fas pathway, probably by favoring the prosurvival genes expression. This study thus provides the detailed mechanism of antiapoptotic and prosurvival effects of lansoprazole for offering gastroprotection against indomethacin-induced gastropathy.

Fatty acid ethyl ester synthase inhibition ameliorates ethanol-induced Ca2+-dependent mitochondrial dysfunction and acute pancreatitis

PubMed Central

Huang, Wei; Booth, David M; Cane, Matthew C; Chvanov, Michael; Javed, Muhammad A; Elliott, Victoria L; Armstrong, Jane A; Dingsdale, Hayley; Cash, Nicole; Li, Yan; Greenhalf, William; Mukherjee, Rajarshi; Kaphalia, Bhupendra S; Jaffar, Mohammed; Petersen, Ole H; Tepikin, Alexei V; Sutton, Robert; Criddle, David N

2014-01-01

Objective Non-oxidative metabolism of ethanol (NOME) produces fatty acid ethyl esters (FAEEs) via carboxylester lipase (CEL) and other enzyme action implicated in mitochondrial injury and acute pancreatitis (AP). This study investigated the relative importance of oxidative and non-oxidative pathways in mitochondrial dysfunction, pancreatic damage and development of alcoholic AP, and whether deleterious effects of NOME are preventable. Design Intracellular calcium ([Ca2+]C), NAD(P)H, mitochondrial membrane potential and activation of apoptotic and necrotic cell death pathways were examined in isolated pancreatic acinar cells in response to ethanol and/or palmitoleic acid (POA) in the presence or absence of 4-methylpyrazole (4-MP) to inhibit oxidative metabolism. A novel in vivo model of alcoholic AP induced by intraperitoneal administration of ethanol and POA was developed to assess the effects of manipulating alcohol metabolism. Results Inhibition of OME with 4-MP converted predominantly transient [Ca2+]C rises induced by low ethanol/POA combination to sustained elevations, with concurrent mitochondrial depolarisation, fall of NAD(P)H and cellular necrosis in vitro. All effects were prevented by 3-benzyl-6-chloro-2-pyrone (3-BCP), a CEL inhibitor. 3-BCP also significantly inhibited rises of pancreatic FAEE in vivo and ameliorated acute pancreatic damage and inflammation induced by administration of ethanol and POA to mice. Conclusions A combination of low ethanol and fatty acid that did not exert deleterious effects per se became toxic when oxidative metabolism was inhibited. The in vitro and in vivo damage was markedly inhibited by blockade of CEL, indicating the potential for development of specific therapy for treatment of alcoholic AP via inhibition of FAEE generation. PMID:24162590

Inhibition of nuclear factor-κB signal by pyrrolidine dithiocarbamate alleviates lipopolysaccharide-induced acute lung injury

PubMed Central

Yang, Hongfu; Sun, Rongqing; Ma, Ning; Liu, Qilong; Sun, Xiaoge; Zi, Panpan; Wang, Junsheng; Chao, Ke; Yu, Lei

2017-01-01

This study mainly studied the effect of inhibition of nuclear factor-κB (NF-κB) signal by pyrrolidine dithiocarbamate (PDTC) on lipopolysaccharide (LPS)-induced inflammatory response, oxidative stress, and mitochondrial dysfunction in a murine acute lung injury model. The results showed that LPS exposure activated NF-κB and its upstream proteins and caused lung inflammation, oxidative stress, and mitochondrial dysfunction in mice. While inhibition of NF-κB by PDTC adminstration alleviated LPS-induced generation of lymphocytes, IL-1β, and TNF-α. Malondialdehyde, a common oxidative product, was markedly reduced after PDTC treatment in LPS-challenged mice. Furthermore, PDTC alleviated LPS-induced mitochondrial dysfunction via improving ATP synthesis and uncoupling protein 2 expression. In conclusion, inhibition of NF-κB by PDTC alleviated LPS-induced acute lung injury via maintaining inflammatory status, oxidative balance, and mitochondrial function in mice. PMID:28521300

Prevention of Acute Kidney Injury by Tauroursodeoxycholic Acid in Rat and Cell Culture Models

PubMed Central

Li, Shunan; Abedin, Md. Joynal; Noppakun, Kajohnsak; Wang, Lawrence; Kaur, Tarundeep; Najafian, Behzad; Rodrigues, Cecília M. P.

2012-01-01

Background Acute kidney injury (AKI) has grave short- and long-term consequences. Often the onset of AKI is predictable, such as following surgery that compromises blood flow to the kidney. Even in such situations, present therapies cannot prevent AKI. As apoptosis is a major form of cell death following AKI, we determined the efficacy and mechanisms of action of tauroursodeoxycholic acid (TUDCA), a molecule with potent anti-apoptotic and pro-survival properties, in prevention of AKI in rat and cell culture models. TUDCA is particularly attractive from a translational standpoint, as it has a proven safety record in animals and humans. Methodology/Principal Findings We chose an ischemia-reperfusion model in rats to simulate AKI in native kidneys, and a human kidney cell culture model to simulate AKI associated with cryopreservation in transplanted kidneys. TUDCA significantly ameliorated AKI in the test models due to inhibition of the mitochondrial pathway of apoptosis and upregulation of survival pathways. Conclusions This study sets the stage for testing TUDCA in future clinical trials for prevention of AKI, an area that needs urgent attention due to lack of effective therapies. PMID:23152827

DHA but Not EPA Emulsions Preserve Neurological and Mitochondrial Function after Brain Hypoxia-Ischemia in Neonatal Mice.

PubMed

Mayurasakorn, Korapat; Niatsetskaya, Zoya V; Sosunov, Sergey A; Williams, Jill J; Zirpoli, Hylde; Vlasakov, Iliyan; Deckelbaum, Richard J; Ten, Vadim S

2016-01-01

Treatment with triglyceride emulsions of docosahexaenoic acid (tri-DHA) protected neonatal mice against hypoxia-ischemia (HI) brain injury. The mechanism of this neuroprotection remains unclear. We hypothesized that administration of tri-DHA enriches HI-brains with DHA/DHA metabolites. This reduces Ca2+-induced mitochondrial membrane permeabilization and attenuates brain injury. 10-day-old C57BL/6J mice following HI-brain injury received tri-DHA, tri-EPA or vehicle. At 4-5 hours of reperfusion, mitochondrial fatty acid composition and Ca2+ buffering capacity were analyzed. At 24 hours and at 8-9 weeks of recovery, oxidative injury, neurofunctional and neuropathological outcomes were evaluated. In vitro, hyperoxia-induced mitochondrial generation of reactive oxygen species (ROS) and Ca2+ buffering capacity were measured in the presence or absence of DHA or EPA. Only post-treatment with tri-DHA reduced oxidative damage and improved short- and long-term neurological outcomes. This was associated with increased content of DHA in brain mitochondria and DHA-derived bioactive metabolites in cerebral tissue. After tri-DHA administration HI mitochondria were resistant to Ca2+-induced membrane permeabilization. In vitro, hyperoxia increased mitochondrial ROS production and reduced Ca2+ buffering capacity; DHA, but not EPA, significantly attenuated these effects of hyperoxia. Post-treatment with tri-DHA resulted in significant accumulation of DHA and DHA derived bioactive metabolites in the HI-brain. This was associated with improved mitochondrial tolerance to Ca2+-induced permeabilization, reduced oxidative brain injury and permanent neuroprotection. Interaction of DHA with mitochondria alters ROS release and improves Ca2+ buffering capacity. This may account for neuroprotective action of post-HI administration of tri-DHA.

Ischaemic accumulation of succinate controls reperfusion injury through mitochondrial ROS

PubMed Central

Gaude, Edoardo; Aksentijević, Dunja; Sundier, Stephanie Y.; Robb, Ellen L.; Logan, Angela; Nadtochiy, Sergiy M.; Ord, Emily N. J.; Smith, Anthony C.; Eyassu, Filmon; Shirley, Rachel; Hu, Chou-Hui; Dare, Anna J.; James, Andrew M.; Rogatti, Sebastian; Hartley, Richard C.; Eaton, Simon; Costa, Ana S.H.; Brookes, Paul S.; Davidson, Sean M.; Duchen, Michael R.; Saeb-Parsy, Kourosh; Shattock, Michael J.; Robinson, Alan J.; Work, Lorraine M.; Frezza, Christian; Krieg, Thomas; Murphy, Michael P.

2014-01-01

Ischaemia-reperfusion (IR) injury occurs when blood supply to an organ is disrupted and then restored, and underlies many disorders, notably heart attack and stroke. While reperfusion of ischaemic tissue is essential for survival, it also initiates oxidative damage, cell death, and aberrant immune responses through generation of mitochondrial reactive oxygen species (ROS)1-5. Although mitochondrial ROS production in IR is established, it has generally been considered a non-specific response to reperfusion1,3. Here, we developed a comparative in vivo metabolomic analysis and unexpectedly identified widely conserved metabolic pathways responsible for mitochondrial ROS production during IR. We showed that selective accumulation of the citric acid cycle (CAC) intermediate succinate is a universal metabolic signature of ischaemia in a range of tissues and is responsible for mitochondrial ROS production during reperfusion. Ischaemic succinate accumulation arises from reversal of succinate dehydrogenase (SDH), which in turn is driven by fumarate overflow from purine nucleotide breakdown and partial reversal of the malate/aspartate shuttle. Upon reperfusion, the accumulated succinate is rapidly re-oxidised by SDH, driving extensive ROS generation by reverse electron transport (RET) at mitochondrial complex I. Decreasing ischaemic succinate accumulation by pharmacological inhibition is sufficient to ameliorate in vivo IR injury in murine models of heart attack and stroke. Thus, we have identified a conserved metabolic response of tissues to ischaemia and reperfusion that unifies many hitherto unconnected aspects of IR injury. Furthermore, these findings reveal a novel pathway for metabolic control of ROS production in vivo, while demonstrating that inhibition of ischaemic succinate accumulation and its oxidation upon subsequent reperfusion is a potential therapeutic target to decrease IR injury in a range of pathologies. PMID:25383517

DHA but Not EPA Emulsions Preserve Neurological and Mitochondrial Function after Brain Hypoxia-Ischemia in Neonatal Mice

PubMed Central

Sosunov, Sergey A.; Williams, Jill J.; Zirpoli, Hylde; Vlasakov, Iliyan; Deckelbaum, Richard J.; Ten, Vadim S.

2016-01-01

Background and Purpose Treatment with triglyceride emulsions of docosahexaenoic acid (tri-DHA) protected neonatal mice against hypoxia-ischemia (HI) brain injury. The mechanism of this neuroprotection remains unclear. We hypothesized that administration of tri-DHA enriches HI-brains with DHA/DHA metabolites. This reduces Ca2+-induced mitochondrial membrane permeabilization and attenuates brain injury. Methods 10-day-old C57BL/6J mice following HI-brain injury received tri-DHA, tri-EPA or vehicle. At 4–5 hours of reperfusion, mitochondrial fatty acid composition and Ca2+ buffering capacity were analyzed. At 24 hours and at 8–9 weeks of recovery, oxidative injury, neurofunctional and neuropathological outcomes were evaluated. In vitro, hyperoxia-induced mitochondrial generation of reactive oxygen species (ROS) and Ca2+ buffering capacity were measured in the presence or absence of DHA or EPA. Results Only post-treatment with tri-DHA reduced oxidative damage and improved short- and long-term neurological outcomes. This was associated with increased content of DHA in brain mitochondria and DHA-derived bioactive metabolites in cerebral tissue. After tri-DHA administration HI mitochondria were resistant to Ca2+-induced membrane permeabilization. In vitro, hyperoxia increased mitochondrial ROS production and reduced Ca2+ buffering capacity; DHA, but not EPA, significantly attenuated these effects of hyperoxia. Conclusions Post-treatment with tri-DHA resulted in significant accumulation of DHA and DHA derived bioactive metabolites in the HI-brain. This was associated with improved mitochondrial tolerance to Ca2+-induced permeabilization, reduced oxidative brain injury and permanent neuroprotection. Interaction of DHA with mitochondria alters ROS release and improves Ca2+ buffering capacity. This may account for neuroprotective action of post-HI administration of tri-DHA. PMID:27513579

Oxidative Damage and Mitochondrial Injuries Are Induced by Various Irrigation Pressures in Rabbit Models of Mild and Severe Hydronephrosis

PubMed Central

Cao, Zhixiu; Yu, Weimin; Li, Wei; Cheng, Fan; Rao, Ting; Yao, Xiaobing; Zhang, Xiaobin; Larré, Stéphane

2015-01-01

Objective We aimed to study whether tolerance to irrigation pressure could be modified by evaluating the oxidative damage of obstructed kidneys based on rabbit models experiencing different degrees of hydronephrosis. Methods A total of 66 rabbits were randomly divided into two experimental groups and a control group. In the experimental groups, the rabbits underwent a surgical procedure inducing mild (group M, n=24) or severe (group S, n=24) hydronephrosis. In each experimental group, the rabbits were then randomly divided into 4 subgroups (M0-M3 and S0-S3) consisting of 6 rabbits each. Group 0 received no perfusion. Groups 1 through 3 were perfused with 20, 60 and 100 mmHg fluid, respectively. For the control group, after a sham operation was performed, the rabbits were divided into 4 subgroups and were perfused with fluid at 0, 20, 60 or 100 mmHg of pressure. Kidney injuries was evaluated by neutrophil gelatinase associated lipocalin (NGAL). Oxidative damage was assessed by analyzing superoxide dismutase (Mn-SOD) activity, malondialdehyde (MDA) levels, glutathione reductase (GR), catalase (CAT) and peroxide (H2O2) levels, mitochondrial injuries was assessed by mitochondrial membrane potential (MMP), the mitochondrial ultrastructure and tubular cell apoptosis. Results In the experimental groups, all results were similar for groups 0 and 1. In group 2, abnormalities were observed in the S group only, and the kidneys of rabbits in group 3 suffered oxidative damage and mitochondrial injuries with increased NGAL, decreased Mn-SOD, GR and CAT,increased MDA and H2O2, lower levels of MMP, mitochondrial vacuolization and an increased apoptotic index. Conclusion In rabbits, severely obstructed kidneys were more susceptible to oxidative damage and mitochondrial injury than mildly obstructed kidneys when subjected to higher degrees of kidney perfusion pressure. PMID:26090815

Mitochondrial Optic Atrophy (OPA) 1 Processing Is Altered in Response to Neonatal Hypoxic-Ischemic Brain Injury

PubMed Central

Baburamani, Ana A.; Hurling, Chloe; Stolp, Helen; Sobotka, Kristina; Gressens, Pierre; Hagberg, Henrik; Thornton, Claire

2015-01-01

Perturbation of mitochondrial function and subsequent induction of cell death pathways are key hallmarks in neonatal hypoxic-ischemic (HI) injury, both in animal models and in term infants. Mitoprotective therapies therefore offer a new avenue for intervention for the babies who suffer life-long disabilities as a result of birth asphyxia. Here we show that after oxygen-glucose deprivation in primary neurons or in a mouse model of HI, mitochondrial protein homeostasis is altered, manifesting as a change in mitochondrial morphology and functional impairment. Furthermore we find that the mitochondrial fusion and cristae regulatory protein, OPA1, is aberrantly cleaved to shorter forms. OPA1 cleavage is normally regulated by a balanced action of the proteases Yme1L and Oma1. However, in primary neurons or after HI in vivo, protein expression of YmelL is also reduced, whereas no change is observed in Oma1 expression. Our data strongly suggest that alterations in mitochondria-shaping proteins are an early event in the pathogenesis of neonatal HI injury. PMID:26393574

Cerium oxide nanoparticles protect endothelial cells from apoptosis induced by oxidative stress.

PubMed

Chen, Shizhu; Hou, Yingjian; Cheng, Gong; Zhang, Cuimiao; Wang, Shuxiang; Zhang, Jinchao

2013-07-01

Oxidative stress is well documented to cause injury to endothelial cells (ECs), which in turn trigger cardiovascular diseases. Previous studies revealed that cerium oxide nanoparticles (nanoceria) had antioxidant property, but the protective effect of nanoceria on ROS injury to ECs and cardiovascular diseases has not been reported. In the current study, we investigated the protective effect and underlying mechanisms of nanoceria on oxidative injury to ECs. The cell viability, lactate dehydrogenase release, cellular uptake, intracellular localization and reactive oxygen species (ROS) levels, endocytosis mechanism, cell apoptosis, and mitochondrial membrane potential were performed. The results indicated that nanoceria had no cytotoxicity on ECs but had the ability to prevent injury by H2O2. Nanoceria could be uptaken into ECs through caveolae- and clathrin-mediated endocytosis and distributed throughout the cytoplasma. The internalized nanoceria effectively attenuated ROS overproduction induced by H2O2. Apoptosis was also alleviated greatly by nanoceria pretreatment. These results may be helpful for more rational application of nanoceria in biomedical fields in the future.

Estrogen-related receptor α is essential for maintaining mitochondrial integrity in cisplatin-induced acute kidney injury.

PubMed

Tsushida, Keigo; Tanabe, Katsuyuki; Masuda, Kana; Tanimura, Satoshi; Miyake, Hiromasa; Arata, Yuka; Sugiyama, Hitoshi; Wada, Jun

2018-04-15

Acute kidney injury (AKI) has been associated with not only higher in-hospital mortality but also the subsequent development of chronic kidney disease (CKD). Recent evidence has suggested the involvement of mitochondrial dysfunction and impaired dynamics in the pathogenesis of AKI. Estrogen-related receptor α (ERRα) is an orphan nuclear receptor that acts as a transcription factor to regulate the transcription of genes required for mitochondrial biogenesis and oxidative phosphorylation. In the present study, we examined the effects of ERRα deficiency on the progression of AKI induced by cisplatin. Male C57BL/6 J wild-type and ERRα -/- mice received a single intraperitoneal injection of 20 mg/kg cisplatin. Seventy-two hours after the injection, kidney function and morphology were evaluated. ERRα expression was observed in renal tubules, and cisplatin inhibited its translocation into nuclei. ERRα deficiency exacerbated cisplatin-induced renal dysfunction and tubular injury, as well as oxidative stress and apoptosis. ERRα -/- mice kidneys revealed lower mitochondrial DNA content and swollen mitochondria with reduced cristae. In addition, these mice had lower expression of the mitochondrial fusion protein mitofusin-2. The cisplatin-induced decrease in mitochondrial DNA and altered mitochondrial structure were more severe in ERRα -/- mice. In cultured mouse proximal tubular epithelial cells, the ERRα inverse agonist XCT-790 significantly inhibited mitofusin-2 expression and induced mitochondrial fragmentation. Taken together, our findings suggest the involvement of ERRα in the progression of cisplatin-induced AKI probably through impaired mitochondrial dynamics. Copyright © 2018 Elsevier Inc. All rights reserved.

Redox imbalance and mitochondrial abnormalities in the diabetic lung.

PubMed

Wu, Jinzi; Jin, Zhen; Yan, Liang-Jun

2017-04-01

Although the lung is one of the least studied organs in diabetes, increasing evidence indicates that it is an inevitable target of diabetic complications. Nevertheless, the underlying biochemical mechanisms of lung injury in diabetes remain largely unexplored. Given that redox imbalance, oxidative stress, and mitochondrial dysfunction have been implicated in diabetic tissue injury, we set out to investigate mechanisms of lung injury in diabetes. The objective of this study was to evaluate NADH/NAD + redox status, oxidative stress, and mitochondrial abnormalities in the diabetic lung. Using STZ induced diabetes in rat as a model, we measured redox-imbalance related parameters including aldose reductase activity, level of poly ADP ribose polymerase (PAPR-1), NAD + content, NADPH content, reduced form of glutathione (GSH), and glucose 6-phophate dehydrogenase (G6PD) activity. For assessment of mitochondrial abnormalities in the diabetic lung, we measured the activities of mitochondrial electron transport chain complexes I to IV and complex V as well as dihydrolipoamide dehydrogenase (DLDH) content and activity. We also measured the protein content of NAD + dependent enzymes such as sirtuin3 (sirt3) and NAD(P)H: quinone oxidoreductase 1 (NQO1). Our results demonstrate that NADH/NAD + redox imbalance occurs in the diabetic lung. This redox imbalance upregulates the activities of complexes I to IV, but not complex V; and this upregulation is likely the source of increased mitochondrial ROS production, oxidative stress, and cell death in the diabetic lung. These results, together with the findings that the protein contents of DLDH, sirt3, and NQO1 all are decreased in the diabetic lung, demonstrate that redox imbalance, mitochondrial abnormality, and oxidative stress contribute to lung injury in diabetes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

ZnPP reduces autophagy and induces apoptosis, thus aggravating liver ischemia/reperfusion injury in vitro.

PubMed

Wang, Yun; Xiong, Xuanxuan; Guo, Hao; Wu, Mingbo; Li, Xiangcheng; Hu, Yuanchao; Xie, Guangwei; Shen, Jian; Tian, Qingzhong

2014-12-01

There is growing evidence indicating that autophagy plays a protective role in liver ischemia/reperfusion (IR) injury. Heme oxygenase-1 (HO-1) can also prevent liver IR injury by limiting inflammation and inducing an anti-apoptotic response. Autophagy also plays a crucial role in liver IR injury. The aim of the present study was to investigate the role of HO-1 in liver IR injury and the association between HO-1, autophagy and apoptotic pathways. IR simulation was performed using buffalo rat liver (BRL) cells, and HO-1 activity was either induced by hemin (HIR group) or inhibited by zinc protoporphyrin (ZnPP) (ZIR group). In the HIR and ZIR group, the expression of HO-1 and autophagy-related genes [light chain 3-Ⅱ (LC3-Ⅱ)] was assessed by RT-qPCR and the protein expression of caspases, autophagy-related genes and genes associated with apoptotic pathways (Bax) was detected by western blot anlaysis. The results of RT-PCR revealed the genetically decreased expression of HO-1 and autophagy-related genes in the ZIR group. Similar results were obtained by western blot analysis and immunofluorescence. An ultrastructural analysis revealed a lower number of autophagosomes in the ZIR group; in the HIR group, the number of autophagosomes was increased. The expression of Bax and cytosolic cytochrome c was increased, while that of Bcl-2 was decreased following treatment of the cells with ZnPP prior to IR simulation; the oppostie occurred in the HIR group. Cleaved caspase-3, caspase-9 and poly(ADP-ribose) polymerase (PARP) protein were activated in the IR and ZIR groups. The disruption of mitochondrial membrane potential was also observed in the ZIR group. In general, the downregulation of HO-1 reduced autophagy and activated the mitochondrial apoptotic pathway.

Febuxostat pretreatment attenuates myocardial ischemia/reperfusion injury via mitochondrial apoptosis.

PubMed

Wang, Shulin; Li, Yunpeng; Song, Xudong; Wang, Xianbao; Zhao, Cong; Chen, Aihua; Yang, Pingzhen

2015-07-02

Febuxostat is a selective inhibitor of xanthine oxidase (XO). XO is a critical source of reactive oxygen species (ROS) during myocardial ischemia/reperfusion (I/R) injury. Inhibition of XO is therapeutically effective in I/R injury. Evidence suggests that febuxostat exerts antioxidant effects by directly scavenging ROS. The present study was performed to investigate the effects of febuxostat on myocardial I/R injury and its underlying mechanisms. We utilized an in vivo mouse model of myocardial I/R injury and an in vitro neonatal rat cardiomyocyte (NRC) model of hypoxia/reoxygenation (H/R) injury. Mice were randomized into five groups: Sham, I/R (I/R + Vehicle), I/R + FEB (I/R + febuxostat), AL + I/R (I/R + allopurinol) and FEB (febuxostat), respectively. The I/R + FEB mice were pretreated with febuxostat (5 mg/kg; i.p.) 24 and 1 h prior to I/R. NRCs received febuxostat (1 and 10 µM) at 24 and 1 h before exposure to hypoxia for 3 h followed by reoxygenation for 3 h. Cardiac function, myocardial infarct size, serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH), and myocardial apoptotic index (AI) were measured in order to ascertain the effects of febuxostat on myocardial I/R injury. Hypoxia/reperfusion (H/R) injury in NRCs was examined using MTT, LDH leakage assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The underlying mechanisms were determined by measuring ROS production, mitochondrial membrane potential (ΔΨm), and expression of cytochrome c, cleaved caspases as well as Bcl-2 protein levels. Myocardial I/R led to an elevation in the myocardial infarct size, serum levels of CK and LDH, cell death and AI. Furthermore, I/R reduced cardiac function. These changes were significantly attenuated by pretreatment with febuxostat and allopurinol, especially by febuxostat. Febuxostat also protected the mitochondrial structure following myocardial I/R, inhibited H/R-induced ROS generation, stabilized the ΔΨm, alleviated cytosolic translocation of mitochondrial cytochrome C, inhibited activation of caspase-3 and -9, upregulated antiapoptotic proteins and downregulated proapoptotic proteins. This study revealed that febuxostat pretreatment mediates the cardioprotective effects against I/R and H/R injury by inhibiting mitochondrial-dependent apoptosis.

Ischemia-reperfusion injury in rat fatty liver: role of nutritional status.

PubMed

Caraceni, P; Nardo, B; Domenicali, M; Turi, P; Vici, M; Simoncini, M; De Maria, N; Trevisani, F; Van Thiel, D H; Derenzini, M; Cavallari, A; Bernardi, M

1999-04-01

Fatty livers are more sensitive to the deleterious effects of ischemia-reperfusion than normal livers. Nutritional status greatly modulates this injury in normal livers, but its role in the specific setting of fatty liver is unknown. This study aimed to determine the effect of nutritional status on warm ischemia-reperfusion injury in rat fatty livers. Fed and fasted rats with normal or fatty liver induced by a choline deficient diet underwent 1 hour of lobar ischemia and reperfusion. Rat survival was determined for 7 days. Serum transaminases, liver histology and cell ultrastructure were assessed before and after ischemia, and at 30 minutes, 2 hours, 8 hours, and 24 hours after reperfusion. Survival was also determined in fatty fasted rats supplemented with glucose before surgery. The preischemic hepatic glycogen was measured in all groups. Whereas survival was similar in fasted and fed rats with normal liver (90% vs. 100%), fasting dramatically reduced survival in rats with fatty liver (14% vs. 64%, P <.01). Accordingly, fasting and fatty degeneration had a synergistic effect in exacerbating liver injury. Mitochondrial damage was a predominant feature of ultrastructural hepatocyte injury in fasted fatty livers. Glucose supplementation partially prevented the fasting-induced depletion of glycogen and improved the 7-day rat survival to 45%. These data indicate that rat fatty livers exposed to normothermic ischemia-reperfusion injury are much more sensitive to fasting than histologically normal livers. Because glucose supplementation improves both the hepatic glycogen stores and the rat survival, a nutritional repletion procedure may be part of a treatment strategy aimed to prevent ischemia-reperfusion injury in fatty livers.

Penehyclidine hydrochloride regulates mitochondrial dynamics and apoptosis through p38MAPK and JNK signal pathways and provides cardioprotection in rats with myocardial ischemia-reperfusion injury.

PubMed

Feng, Min; Wang, Lirui; Chang, Siyuan; Yuan, Pu

2018-05-31

The potential mechanism of penehyclidine hydrochloride (PHC) against myocardial ischemia-reperfusion (I/R) injury has not been fully elucidated. The aim of the present study was to reveal whether mitochondrial dynamics, apoptosis, and MAPKs were involved in the cardioprotective effect of this drug on myocardial I/R injury. Ninety healthy adult male Wistar rats were separately pretreated with normal saline (0.9%); PHC; and signal pathway blockers of MAPKs, Drp1, and Bcl-2. Coronary artery ligation and subsequent reperfusion were performed to induce myocardial I/R injury. Echocardiography was performed. Myocardial enzymes and oxidative stress markers were detected. Myocardial cell apoptotic rates and infarct sizes were measured. Mitochondrial function was evaluated. Expression levels of MAPKs, mitochondria regulatory proteins (Drp1, Mfn1/2), and apoptosis-related proteins (Bcl-2, Bax) were determined. PHC pretreatment improved myocardial abnormalities (dysfunction, injury, infarct size, and apoptotic rate), mitochondrial abnormalities (dysfunction and fission), and excessive oxidative stress and inhibited the activities of p38MAPK and JNK signal pathways in rats with myocardial I/R injury (P < 0.05). Additionally, p38MAPK and JNK blockers (SB239063 and SP600125, respectively) had an effect on rats same as that of PHC. Although Drp1 blocker (Mdivi-1) showed a similar cardioprotective effect (P < 0.05), it did not affect the expression of MAPKs and apoptosis-related proteins (P > 0.05). In addition, Bcl-2 blocker (ABT-737) caused a high expression of Drp1 and a low expression of Mfn1/2 (P < 0.05). PHC regulated mitochondrial dynamics and apoptosis through p38MAPK and JNK signal pathways and provided cardioprotection in rats with myocardial I/R injury. Copyright © 2018 Elsevier B.V. All rights reserved.

Combinatorial usage of fungal polysaccharides from Cordyceps sinensis and Ganoderma atrum ameliorate drug-induced liver injury in mice.

PubMed

Fan, Songtao; Huang, Xiaojun; Wang, Sunan; Li, Chang; Zhang, Zhihong; Xie, Mingyong; Nie, Shaoping

2018-05-15

This study investigated the possible protective effect of combined fungal polysaccharides (CFP), consisting of Cordyceps sinensis polysaccharides (CSP) and Ganoderma atrum polysaccharides (PSG) with well-defined structural characteristics, against cyclophosphamide (CTX)-induced hepatotoxicity in mice. Our results indicated CFP effectively prevented the liver injury by decreasing toxicity markers (aspartate transaminase, alanine aminotransferase and alkaline phosphatase). Further biochemical and molecular analysis indicated CSP particularly inhibited the activation of Toll-like receptor 9 (TLR9) and its related inflammatory signals, including pro-inflammatory cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 to modulate hepatic inflammation response. Relatively, through activation of peroxisome proliferator-activated receptor α (PPARα), PSG increased hepatic glutathione peroxidase and glutathione content depleted by CTX, as well as prevented mitochondria-dependent apoptosis with regulation on Bcl-2 family proteins (Bad, Bax and Bcl-2). In addition, protective effect of CFP was associated with enhanced modulations on cellular oxidant/antioxidant imbalance, mitochondrial apoptotic pathway and pro-inflammatory factors via PPARα upregulation and TLR9 downregulation. Taking together, the combinatorial approach based on CSP and PSG presented a practical option for the management of drug-induced liver injury. Copyright © 2018 Elsevier Ltd. All rights reserved.

Activation of G protein‐coupled oestrogen receptor 1 at the onset of reperfusion protects the myocardium against ischemia/reperfusion injury by reducing mitochondrial dysfunction and mitophagy

PubMed Central

Feng, Yansheng; Madungwe, Ngonidzashe B; da Cruz Junho, Carolina Victoria

2017-01-01

Background and Purpose Recent evidence indicates that GPER (G protein‐coupled oestrogen receptor 1) mediates acute pre‐ischaemic oestrogen‐induced protection of the myocardium from ischaemia/reperfusion injury via a signalling cascade that includes PKC translocation, ERK1/2/ GSK‐3β phosphorylation and inhibition of the mitochondrial permeability transition pore (mPTP) opening. Here, we investigated the impact and mechanism involved in post‐ischaemic GPER activation in ischaemia/reperfusion injury. We determined whether GPER activation at the onset of reperfusion confers cardioprotective effects by protecting against mitochondrial impairment and mitophagy. Experimental Approach In vivo rat hearts were subjected to ischaemia followed by reperfusion with oestrogen (17β‐oestradiol, E2), E2 + G15, a GPER antagonist, or vehicle. Myocardial infarct size, the threshold for the opening of mPTP, mitophagy, mitochondrial membrane potential, ROS production, proteins ubiquitinated including cyclophilin D, and phosphorylation levels of ERK and GSK‐3β were measured. Results We found that post‐ischaemic E2 administration to both male and female ovariectomized‐rats reduced myocardial infarct size. Post‐ischaemic E2 administration preserved mitochondrial structural integrity and this was associated with a decrease in ROS production and increased mitochondrial membrane potential, as well as an increase in the mitochondrial Ca2+ load required to induce mPTP opening via activation of the MEK/ERK/GSK‐3β axis. Moreover, E2 reduced mitophagy via the PINK1/Parkin pathway involving LC3I, LC3II and p62 proteins. All these post‐ischaemic effects of E2 were abolished by G15 suggesting a GPER‐dependent mechanism. Conclusion These results indicate that post‐ischaemic GPER activation induces cardioprotective effects against ischaemia/reperfusion injury in males and females by protecting mitochondrial structural integrity and function and reducing mitophagy. PMID:28906548

Nrf2 inhibits oxaliplatin-induced peripheral neuropathy via protection of mitochondrial function.

PubMed

Yang, Yang; Luo, Lan; Cai, Xueting; Fang, Yuan; Wang, Jiaqi; Chen, Gang; Yang, Jie; Zhou, Qian; Sun, Xiaoyan; Cheng, Xiaolan; Yan, Huaijiang; Lu, Wuguang; Hu, Chunping; Cao, Peng

2018-05-20

Oxaliplatin-induced peripheral neuropathy (OIPN) is a severe, dose-limiting toxicity associated with cancer chemotherapy. The efficacy of antioxidant administration in OIPN is debatable, as the promising preliminary results obtained with a number of antioxidants have not been confirmed in larger clinical trials. Besides its antioxidant activity, the transcription factor, nuclear factor-erythroid 2 (NF-E2) p45-related factor 2 (Nrf2) plays a crucial role in the maintenance of mitochondrial homeostasis, and mitochondrial dysfunction is a key contributor to OIPN. Here, we have investigated the protective properties of Nrf2 in OIPN. Nrf2 -/- mice displayed severe mechanical allodynia and cold sensitivity and thus experienced increased peripheral nervous system injury compared to Nrf2 +/+ mice. Furthermore, Nrf2 knockout aggravated oxaliplatin-induced reactive oxygen species production, decreased the mitochondrial membrane potential, led to abnormal intracellular calcium levels, and induced cytochrome c-related apoptosis and overexpression of the TRP protein family. Sulforaphane-induced activation of the Nrf2 signaling pathway alleviated morphological alterations, mitochondrial dysfunction in dorsal root ganglion neurons, and nociceptive sensations in mice. Our findings reveal that Nrf2 may play a critical role in ameliorating OIPN, through protection of mitochondrial function by alleviating oxidative stress and inhibiting TRP protein family expression. This suggests that pharmacological or therapeutic activation of Nrf2 may be used to prevent or slow down the progression of OIPN. Copyright © 2018 Elsevier Inc. All rights reserved.

Levosimendan: a cardiovascular drug to prevent liver ischemia-reperfusion injury?

PubMed

Onody, Peter; Stangl, Rita; Fulop, Andras; Rosero, Oliver; Garbaisz, David; Turoczi, Zsolt; Lotz, Gabor; Rakonczay, Zoltan; Balla, Zsolt; Hegedus, Viktor; Harsanyi, Laszlo; Szijarto, Attila

2013-01-01

Temporary occlusion of the hepatoduodenal ligament leads to an ischemic-reperfusion (IR) injury in the liver. Levosimendan is a new positive inotropic drug, which induces preconditioning-like adaptive mechanisms due to opening of mitochondrial KATP channels. The aim of this study was to examine possible protective effects of levosimendan in a rat model of hepatic IR injury. Levosimendan was administered to male Wistar rats 1 hour (early pretreatment) or 24 hours (late pretreatment) before induction of 60-minute segmental liver ischemia. Microcirculation of the liver was monitored by laser Doppler flowmeter. After 24 hours of reperfusion, liver and blood samples were taken for histology, immuno- and enzyme-histochemistry (TUNEL; PARP; NADH-TR) as well as for laboratory tests. Furthermore, liver antioxidant status was assessed and HSP72 expression was measured. In both groups pretreated with levosimendan, significantly better hepatic microcirculation was observed compared to respective IR control groups. Similarly, histological damage was also reduced after levosimendan administration. This observation was supported by significantly lower activities of serum ALT (p early = 0.02; p late = 0.005), AST (p early = 0.02; p late = 0.004) and less DNA damage by TUNEL test (p early = 0.05; p late = 0.034) and PAR positivity (p early = 0.02; p late = 0.04). Levosimendan pretreatment resulted in significant improvement of liver redox homeostasis. Further, significantly better mitochondrial function was detected in animals receiving late pretreatment. Finally, HSP72 expression was increased by IR injury, but it was not affected by levosimendan pretreatment. Levosimendan pretreatment can be hepatoprotective and it could be useful before extensive liver resection.

Permeabilization of brain tissue in situ enables multiregion analysis of mitochondrial function in a single mouse brain.

PubMed

Herbst, Eric A F; Holloway, Graham P

2015-02-15

Mitochondrial function in the brain is traditionally assessed through analysing respiration in isolated mitochondria, a technique that possesses significant tissue and time requirements while also disrupting the cooperative mitochondrial reticulum. We permeabilized brain tissue in situ to permit analysis of mitochondrial respiration with the native mitochondrial morphology intact, removing the need for isolation time and minimizing tissue requirements to ∼2 mg wet weight. The permeabilized brain technique was validated against the traditional method of isolated mitochondria and was then further applied to assess regional variation in the mouse brain with ischaemia-reperfusion injuries. A transgenic mouse model overexpressing catalase within mitochondria was applied to show the contribution of mitochondrial reactive oxygen species to ischaemia-reperfusion injuries in different brain regions. This technique enhances the accessibility of addressing physiological questions in small brain regions and in applying transgenic mouse models to assess mechanisms regulating mitochondrial function in health and disease. Mitochondria function as the core energy providers in the brain and symptoms of neurodegenerative diseases are often attributed to their dysregulation. Assessing mitochondrial function is classically performed in isolated mitochondria; however, this process requires significant isolation time, demand for abundant tissue and disruption of the cooperative mitochondrial reticulum, all of which reduce reliability when attempting to assess in vivo mitochondrial bioenergetics. Here we introduce a method that advances the assessment of mitochondrial respiration in the brain by permeabilizing existing brain tissue to grant direct access to the mitochondrial reticulum in situ. The permeabilized brain preparation allows for instant analysis of mitochondrial function with unaltered mitochondrial morphology using significantly small sample sizes (∼2 mg), which permits the analysis of mitochondrial function in multiple subregions within a single mouse brain. Here this technique was applied to assess regional variation in brain mitochondrial function with acute ischaemia-reperfusion injuries and to determine the role of reactive oxygen species in exacerbating dysfunction through the application of a transgenic mouse model overexpressing catalase within mitochondria. Through creating accessibility to small regions for the investigation of mitochondrial function, the permeabilized brain preparation enhances the capacity for examining regional differences in mitochondrial regulation within the brain, as the majority of genetic models used for unique approaches exist in the mouse model. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Autophagy activation promotes removal of damaged mitochondria and protects against renal tubular injury induced by albumin overload.

PubMed

Tan, Jin; Wang, Miaohong; Song, Shuling; Miao, Yuyang; Zhang, Qiang

2018-01-10

Proteinuria (albuminuria) is an important cause of aggravating tubulointerstitial injury. Previous studies have shown that autophagy activation can alleviate renal tubular epithelial cell injury caused by urinary protein, but the mechanism is not clear. Here, we investigated the role of clearance of damaged mitochondria in this protective effect. We found that albumin overload induces a significant increase in turnover of LC3-II and decrease in p62 protein level in renal proximal tubular (HK-2) cells in vitro. Albumin overload also induces an increase in mitochondrial damage. ALC, a mitochondrial torpent, alleviates mitochondrial damage induced by albumin overload and also decreases autophagy, while mitochondrial damage revulsant CCCP further increases autophagy. Furthermore, pretreatment of HK-2 cells with rapamycin reduced the amount of damaged mitochondria and the level of apoptosis induced by albumin overload. In contrast, blocking autophagy with chloroquine exerted an opposite effect. Taken together, our results indicated autophagy activation promotes removal of damaged mitochondria and protects against renal tubular injury caused by albumin overload. This further confirms previous research that autophagy activation is an adaptive response in renal tubular epithelial cells after urinary protein overload.

The Crucial Role of Early Mitochondrial Injury in L-Lysine-Induced Acute Pancreatitis

PubMed Central

Biczó, György; Hegyi, Péter; Dósa, Sándor; Shalbuyeva, Natalia; Berczi, Sándor; Sinervirta, Riitta; Hracskó, Zsuzsanna; Siska, Andrea; Kukor, Zoltán; Jármay, Katalin; Venglovecz, Viktória; Varga, Ilona S.; Iványi, Béla; Alhonen, Leena; Wittmann, Tibor; Gukovskaya, Anna; Takács, Tamás

2011-01-01

Abstract Aims Large doses of intraperitoneally injected basic amino acids, L-arginine, or L-ornithine, induce acute pancreatitis in rodents, although the mechanisms mediating pancreatic toxicity remain unknown. Another basic amino acid, L-lysine, was also shown to cause pancreatic acinar cell injury. The aim of the study was to get insight into the mechanisms through which L-lysine damages the rat exocrine pancreas, in particular to characterize the kinetics of L-lysine-induced mitochondrial injury, as well as the pathologic responses (including alteration of antioxidant systems) characteristic of acute pancreatitis. Results We showed that intraperitoneal administration of 2 g/kg L-lysine induced severe acute necrotizing pancreatitis. L-lysine administration caused early pancreatic mitochondrial damage that preceded the activation of trypsinogen and the proinflammatory transcription factor nuclear factor-κB (NF-κB), which are commonly thought to play an important role in the development of acute pancreatitis. Our data demonstrate that L-lysine impairs adenosine triphosphate synthase activity of isolated pancreatic, but not liver, mitochondria. Innovation and Conclusion Taken together, early mitochondrial injury caused by large doses of L-lysine may lead to the development of acute pancreatitis independently of pancreatic trypsinogen and NF-κB activation. PMID:21644850

Quercetin Exerts Differential Neuroprotective Effects Against H2O2 and Aβ Aggregates in Hippocampal Neurons: the Role of Mitochondria.

PubMed

Godoy, Juan A; Lindsay, Carolina B; Quintanilla, Rodrigo A; Carvajal, Francisco J; Cerpa, Waldo; Inestrosa, Nibaldo C

2017-11-01

Amyloid-β peptide (Aβ) is one of the major players in the pathogenesis of Alzheimer's disease (AD). Despite numerous studies, the mechanisms by which Aβ induces neurodegeneration are not completely understood. Oxidative stress is considered a major contributor to the pathogenesis of AD, and accumulating evidence indicates that high levels of reactive oxygen species (ROS) are involved in Aβ-induced neurodegeneration. Moreover, Aβ can induce the deregulation of calcium homeostasis, which also affects mitochondrial function and triggers neuronal cell death. In the present study, we analyzed the effects of quercetin, a plant flavonoid with antioxidant properties, on oxidative stress- and Aβ-induced degeneration. Our results indicate that quercetin efficiently protected against H 2 O 2 -induced neuronal toxicity; however, this protection was only partial in rat hippocampal neurons that were treated with Aβ. Treatment with quercetin decreased ROS levels, recovered the normal morphology of mitochondria, and prevented mitochondrial dysfunction in neurons that were treated with H 2 O 2 . By contrast, quercetin treatment partially rescued hippocampal neurons from Aβ-induced mitochondrial injury. Most importantly, quercetin treatment prevented the toxic effects that are induced by H 2 O 2 in hippocampal neurons and, to a lesser extent, the Aβ-induced toxicity that is associated with the superoxide anion, which is a precursor of ROS production in mitochondria. Collectively, these results indicate that quercetin exerts differential effects on the prevention of H 2 O 2 - and Aβ-induced neurotoxicity in hippocampal neurons and may be a powerful tool for dissecting the molecular mechanisms underlying Aβ neurotoxicity.

Expression and function of Kv7.4 channels in rat cardiac mitochondria: possible targets for cardioprotection.

PubMed

Testai, Lara; Barrese, Vincenzo; Soldovieri, Maria Virginia; Ambrosino, Paolo; Martelli, Alma; Vinciguerra, Iolanda; Miceli, Francesco; Greenwood, Iain Andrew; Curtis, Michael John; Breschi, Maria Cristina; Sisalli, Maria Josè; Scorziello, Antonella; Canduela, Miren Josune; Grandes, Pedro; Calderone, Vincenzo; Taglialatela, Maurizio

2016-05-01

Plasmalemmal Kv7.1 (KCNQ1) channels are critical players in cardiac excitability; however, little is known on the functional role of additional Kv7 family members (Kv7.2-5) in cardiac cells. In this work, the expression, function, cellular and subcellular localization, and potential cardioprotective role against anoxic-ischaemic cardiac injury of Kv7.4 channels have been investigated. Expression of Kv7.1 and Kv7.4 transcripts was found in rat heart tissue by quantitative polymerase chain reaction. Western blots detected Kv7.4 subunits in mitochondria from Kv7.4-transfected cells, H9c2 cardiomyoblasts, freshly isolated adult cardiomyocytes, and whole hearts. Immunofluorescence experiments revealed that Kv7.4 subunits co-localized with mitochondrial markers in cardiac cells, with ∼ 30-40% of cardiac mitochondria being labelled by Kv7.4 antibodies, a result also confirmed by immunogold electron microscopy experiments. In isolated cardiac (but not liver) mitochondria, retigabine (1-30 µM) and flupirtine (30 µM), two selective Kv7 activators, increased Tl(+) influx, depolarized the membrane potential, and inhibited calcium uptake; all these effects were antagonized by the Kv7 blocker XE991. In intact H9c2 cells, reducing Kv7.4 expression by RNA interference blunted retigabine-induced mitochondrial membrane depolarization; in these cells, retigabine decreased mitochondrial Ca(2+) levels and increased radical oxygen species production, both effects prevented by XE991. Finally, retigabine reduced cellular damage in H9c2 cells exposed to anoxia/re-oxygenation and largely prevented the functional and morphological changes triggered by global ischaemia/reperfusion (I/R) in Langendorff-perfused rat hearts. Kv7.4 channels are present and functional in cardiac mitochondria; their activation exerts a significant cardioprotective role, making them potential therapeutic targets against I/R-induced cardiac injury. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Aldehydic load and aldehyde dehydrogenase 2 profile during the progression of post-myocardial infarction cardiomyopathy: benefits of Alda-1

PubMed Central

Gomes, Katia M.S.; Bechara, Luiz R.G.; Lima, Vanessa M.; Ribeiro, Márcio A.C.; Campos, Juliane C.; Dourado, Paulo M.; Kowaltowski, Alicia J.; Mochly-Rosen, Daria; Ferreira, Julio C.B.

2015-01-01

Background/Objectives We previously demonstrated that reducing cardiac aldehydic load by aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme responsible for metabolizing the major lipid peroxidation product, protects against acute ischemia/reperfusion injury and chronic heart failure. However, time-dependent changes in ALDH2 profile, aldehydic load and mitochondrial bioenergetics during progression of post-myocardial infarction (post-MI) cardiomyopathy is unknown and should be established to determine the optimal time window for drug treatment. Methods Here we characterized cardiac ALDH2 activity and expression, lipid peroxidation, 4-hydroxy-2-nonenal (4-HNE) adduct formation, glutathione pool and mitochondrial energy metabolism and H2O2 release during the 4 weeks after permanent left anterior descending (LAD) coronary artery occlusion in rats. Results We observed a sustained disruption of cardiac mitochondrial function during the progression of post-MI cardiomyopathy, characterized by >50% reduced mitochondrial respiratory control ratios and up to 2 fold increase in H2O2 release. Mitochondrial dysfunction was accompanied by accumulation of cardiac and circulating lipid peroxides and 4-HNE protein adducts and down-regulation of electron transport chain complexes I and V. Moreover, increased aldehydic load was associated with a 90% reduction in cardiac ALDH2 activity and increased glutathione pool. Further supporting an ALDH2 mechanism, sustained Alda-1 treatment (starting 24hrs after permanent LAD occlusion surgery) prevented aldehydic overload, mitochondrial dysfunction and improved ventricular function in post-MI cardiomyopathy rats. Conclusion Taken together, our findings demonstrate a disrupted mitochondrial metabolism along with an insufficient cardiac ALDH2-mediated aldehyde clearance during the progression of ventricular dysfunction, suggesting a potential therapeutic value of ALDH2 activators during the progression of post-myocardial infarction cardiomyopathy. PMID:25464432

TRPM2 Channels Protect against Cardiac Ischemia-Reperfusion Injury

PubMed Central

Miller, Barbara A.; Hoffman, Nicholas E.; Merali, Salim; Zhang, Xue-Qian; Wang, JuFang; Rajan, Sudarsan; Shanmughapriya, Santhanam; Gao, Erhe; Barrero, Carlos A.; Mallilankaraman, Karthik; Song, Jianliang; Gu, Tongda; Hirschler-Laszkiewicz, Iwona; Koch, Walter J.; Feldman, Arthur M.; Madesh, Muniswamy; Cheung, Joseph Y.

2014-01-01

Cardiac TRPM2 channels were activated by intracellular adenosine diphosphate-ribose and blocked by flufenamic acid. In adult cardiac myocytes the ratio of GCa to GNa of TRPM2 channels was 0.56 ± 0.02. To explore the cellular mechanisms by which TRPM2 channels protect against cardiac ischemia/reperfusion (I/R) injury, we analyzed proteomes from WT and TRPM2 KO hearts subjected to I/R. The canonical pathways that exhibited the largest difference between WT-I/R and KO-I/R hearts were mitochondrial dysfunction and the tricarboxylic acid cycle. Complexes I, III, and IV were down-regulated, whereas complexes II and V were up-regulated in KO-I/R compared with WT-I/R hearts. Western blots confirmed reduced expression of the Complex I subunit and other mitochondria-associated proteins in KO-I/R hearts. Bioenergetic analyses revealed that KO myocytes had a lower mitochondrial membrane potential, mitochondrial Ca2+ uptake, ATP levels, and O2 consumption but higher mitochondrial superoxide levels. Additionally, mitochondrial Ca2+ uniporter (MCU) currents were lower in KO myocytes, indicating reduced mitochondrial Ca2+ uptake was likely due to both lower ψm and MCU activity. Similar to isolated myocytes, O2 consumption and ATP levels were also reduced in KO hearts. Under a simulated I/R model, aberrant mitochondrial bioenergetics was exacerbated in KO myocytes. Reactive oxygen species levels were also significantly higher in KO-I/R compared with WT-I/R heart slices, consistent with mitochondrial dysfunction in KO-I/R hearts. We conclude that TRPM2 channels protect the heart from I/R injury by ameliorating mitochondrial dysfunction and reducing reactive oxygen species levels. PMID:24492610

Insulin alleviates mitochondrial oxidative stress involving upregulation of superoxide dismutase 2 and uncoupling protein 2 in septic acute kidney injury

PubMed Central

Chen, Guang-Dao; Zhang, Jun-Liang; Chen, Yi-Ting; Zhang, Ju-Xing; Wang, Tao; Zeng, Qi-Yi

2018-01-01

The aim of the present study was to explore the effects and mechanisms of insulin on mitochondrial oxidative stress in septic acute kidney injury (AKI). Male Sprague Dawley rats were divided randomly into four groups: Control group, sham surgery group, cecal ligation and puncture (CLP) group, and CLP plus insulin group. Blood specimens and kidney tissues were obtained at 12 and 24 h after surgery as separate experiments. Analyses of histology and indicators of renal injury [blood urea nitrogen (BUN) and serum creatinine (CRE) and neutrophil gelatinase-associated lipocalin (NGAL)], mitochondrial function [adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP)], oxidative stress [inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS) and nitric oxide (NO)], endogenous antioxidant systems [superoxide dismutase (SOD) and glutathione (GSH)] as well as the expression of uncoupling protein (UCP), PINK1 protein (a major mediator of mitophagy), PGC1α protein (a major regulator of mitochondrial biogenesis) were performed. Compared with CLP group, the CLP plus insulin group had milder histological damage, higher levels of ATP and MMP as well as lower levels of BUN, serum CRE and NGAL, intrarenal iNOS, mitochondrial ROS and total NO. Moreover, the CLP plus insulin group demonstrated increased expression of SOD2 and UCP2. In contrast, insulin administration suppressed mitophagy meanwhile did not upregulate total GSH and induce mitochondrial biogenesis following CLP. These findings indicated that the upregulation of SOD2 and UCP2 may be involved in insulin protecting against mitochondrial oxidative stress in septic AKI. PMID:29563990

Insulin alleviates mitochondrial oxidative stress involving upregulation of superoxide dismutase 2 and uncoupling protein 2 in septic acute kidney injury.

PubMed

Chen, Guang-Dao; Zhang, Jun-Liang; Chen, Yi-Ting; Zhang, Ju-Xing; Wang, Tao; Zeng, Qi-Yi

2018-04-01

The aim of the present study was to explore the effects and mechanisms of insulin on mitochondrial oxidative stress in septic acute kidney injury (AKI). Male Sprague Dawley rats were divided randomly into four groups: Control group, sham surgery group, cecal ligation and puncture (CLP) group, and CLP plus insulin group. Blood specimens and kidney tissues were obtained at 12 and 24 h after surgery as separate experiments. Analyses of histology and indicators of renal injury [blood urea nitrogen (BUN) and serum creatinine (CRE) and neutrophil gelatinase-associated lipocalin (NGAL)], mitochondrial function [adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP)], oxidative stress [inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS) and nitric oxide (NO)], endogenous antioxidant systems [superoxide dismutase (SOD) and glutathione (GSH)] as well as the expression of uncoupling protein (UCP), PINK1 protein (a major mediator of mitophagy), PGC1α protein (a major regulator of mitochondrial biogenesis) were performed. Compared with CLP group, the CLP plus insulin group had milder histological damage, higher levels of ATP and MMP as well as lower levels of BUN, serum CRE and NGAL, intrarenal iNOS, mitochondrial ROS and total NO. Moreover, the CLP plus insulin group demonstrated increased expression of SOD2 and UCP2. In contrast, insulin administration suppressed mitophagy meanwhile did not upregulate total GSH and induce mitochondrial biogenesis following CLP. These findings indicated that the upregulation of SOD2 and UCP2 may be involved in insulin protecting against mitochondrial oxidative stress in septic AKI.

Acute high-altitude hypoxic brain injury: Identification of ten differential proteins

PubMed Central

Li, Jianyu; Qi, Yuting; Liu, Hui; Cui, Ying; Zhang, Li; Gong, Haiying; Li, Yaxiao; Li, Lingzhi; Zhang, Yongliang

2013-01-01

Hypobaric hypoxia can cause severe brain damage and mitochondrial dysfunction, and is involved in hypoxic brain injury. However, little is currently known about the mechanisms responsible for mitochondrial dysfunction in hypobaric hypoxic brain damage. In this study, a rat model of hypobaric hypoxic brain injury was established to investigate the molecular mechanisms associated with mitochondrial dysfunction. As revealed by two-dimensional electrophoresis analysis, 16, 21, and 36 differential protein spots in cerebral mitochondria were observed at 6, 12, and 24 hours post-hypobaric hypoxia, respectively. Furthermore, ten protein spots selected from each hypobaric hypoxia subgroup were similarly regulated and were identified by mass spectrometry. These detected proteins included dihydropyrimidinase-related protein 2, creatine kinase B-type, isovaleryl-CoA dehydrogenase, elongation factor Ts, ATP synthase beta-subunit, 3-mercaptopyruvate sulfurtransferase, electron transfer flavoprotein alpha-subunit, Chain A of 2-enoyl-CoA hydratase, NADH dehydrogenase iron-sulfur protein 8 and tropomyosin beta chain. These ten proteins are all involved in the electron transport chain and the function of ATP synthase. Our findings indicate that hypobaric hypoxia can induce the differential expression of several cerebral mitochondrial proteins, which are involved in the regulation of mitochondrial energy production. PMID:25206614

Autophagy in sepsis: Degradation into exhaustion?

PubMed

Ho, Jeffery; Yu, Jun; Wong, Sunny H; Zhang, Lin; Liu, Xiaodong; Wong, Wai T; Leung, Czarina C H; Choi, Gordon; Wang, Maggie H T; Gin, Tony; Chan, Matthew T V; Wu, William K K

2016-07-02

Autophagy is one of the innate immune defense mechanisms against microbial challenges. Previous in vitro and in vivo models of sepsis demonstrated that autophagy was activated initially in sepsis, followed by a subsequent phase of impairment. Autophagy modulation appears to be protective against multiple organ injuries in these murine sepsis models. This is achieved in part by preventing apoptosis, maintaining a balance between the productions of pro- and anti-inflammatory cytokines, and preserving mitochondrial functions. This article aims to discuss the role of autophagy in sepsis and the therapeutic potential of autophagy enhancers.

Progesterone induces neuroprotection following reperfusion-promoted mitochondrial dysfunction after focal cerebral ischemia in rats.

PubMed

Andrabi, Syed Suhail; Parvez, Suhel; Tabassum, Heena

2017-06-01

Organelle damage and increases in mitochondrial permeabilization are key events in the development of cerebral ischemic tissue injury because they cause both modifications in ATP turnover and cellular apoptosis/necrosis. Early restoration of blood flow and improvement of mitochondrial function might reverse the situation and help in recovery following an onset of stroke. Mitochondria and related bioenergetic processes can be effectively used as pharmacological targets. Progesterone (P4), one of the promising neurosteroids, has been found to be neuroprotective in various models of neurological diseases, through a number of mechanisms. This influenced us to investigate the possible role of P4 in the mitochondria-mediated neuroprotective mechanism in an ischemic stroke model of rat. In this study, we have shown the positive effect of P4 administration on behavioral deficits and mitochondrial health in an ischemic stroke injury model of transient middle cerebral artery occlusion (tMCAO). After induction of tMCAO, the rats received an initial intraperitoneal injection of P4 (8 mg/kg body weight) or vehicle at 1 h post-occlusion followed by subcutaneous injections at 6, 12 and 18 h. Behavioral assessment for functional deficits included grip strength, motor coordination and gait analysis. Findings revealed a significant improvement with P4 treatment in tMCAO animals. Staining of isolated brain slices from P4-treated rats with 2,3,5-triphenyltetrazolium chloride (TTC) showed a reduction in the infarct area in comparison to the vehicle group, indicating the presence of an increased number of viable mitochondria. P4 treatment was also able to attenuate mitochondrial reactive oxygen species (ROS) production, as well as block the mitochondrial permeability transition pore (mPTP), in the tMCAO injury model. In addition, it was also able to ameliorate the altered mitochondrial membrane potential and respiration ratio in the ischemic animals, thereby suggesting that P4 has a positive effect on mitochondrial bioenergetics. In conclusion, these results demonstrate that P4 treatment is beneficial in preserving the mitochondrial functions that are altered in cerebral ischemic injury and thus can help in defining better therapies. © 2017. Published by The Company of Biologists Ltd.

Mitochondrial Permeability Transition in Pathogenesis of Hemorrhagic Injury: Targeted Therapy with Minocycline

DTIC Science & Technology

2012-03-01

minocy- cline treatment (Figures 1-4). Minocycline also improved mitochondrial function as assessed by intravital multiphoton imaging of the...will make direct measurements by intravital multiphoton microscopy to determine whether onset of the mitochondrial permeability transition and...oxidative stress were assessed 6 h after resuscitation. Mitochondrial polarization were assessed by intravital microscopy. After H/R with vehicle or

Impaired Cerebral Mitochondrial Oxidative Phosphorylation Function in a Rat Model of Ventricular Fibrillation and Cardiopulmonary Resuscitation

PubMed Central

Fu, Yue; Xu, Wen; Jiang, Longyuan; Huang, Zitong

2014-01-01

Postcardiac arrest brain injury significantly contributes to mortality and morbidity in patients suffering from cardiac arrest (CA). Evidence that shows that mitochondrial dysfunction appears to be a key factor in tissue damage after ischemia/reperfusion is accumulating. However, limited data are available regarding the cerebral mitochondrial dysfunction during CA and cardiopulmonary resuscitation (CPR) and its relationship to the alterations of high-energy phosphate. Here, we sought to identify alterations of mitochondrial morphology and oxidative phosphorylation function as well as high-energy phosphates during CA and CPR in a rat model of ventricular fibrillation (VF). We found that impairment of mitochondrial respiration and partial depletion of adenosine triphosphate (ATP) and phosphocreatine (PCr) developed in the cerebral cortex and hippocampus following a prolonged cardiac arrest. Optimal CPR might ameliorate the deranged phosphorus metabolism and preserve mitochondrial function. No obvious ultrastructural abnormalities of mitochondria have been found during CA. We conclude that CA causes cerebral mitochondrial dysfunction along with decay of high-energy phosphates, which would be mitigated with CPR. This study may broaden our understanding of the pathogenic processes underlying global cerebral ischemic injury and provide a potential therapeutic strategy that aimed at preserving cerebral mitochondrial function during CA. PMID:24696844

Effect of nerve injury on the number of dorsal root ganglion neurons and autotomy behavior in adult Bax-deficient mice.

PubMed

Lyu, Chuang; Lyu, Gong-Wei; Martinez, Aurora; Shi, Tie-Jun Sten

2017-01-01

The proapoptotic molecule BAX, plays an important role in mitochondrial apoptotic pathway. Dorsal root ganglion (DRG) neurons depend on neurotrophic factors for survival at early developmental stages. Withdrawal of neurotrophic factors will induce apoptosis in DRG neurons, but this type of cell death can be delayed or prevented in neonatal Bax knockout (KO) mice. In adult animals, evidence also shows that DRG neurons are less dependent upon neurotrophic factors for survival. However, little is known about the effect of Bax deletion on the survival of normal and denervated DRG neurons in adult mice. A unilateral sciatic nerve transection was performed in adult Bax KO mice and wild-type (WT) littermates. Stereological method was employed to quantify the number of lumbar-5 DRG neurons 1 month post-surgery. Nerve injury-induced autotomy behavior was also examined on days 1, 3, and 7 post-surgery. There were significantly more neurons in contralateral DRGs of KO mice as compared with WT mice. The number of neurons was reduced in ipsilateral DRGs in both KO and WT mice. No changes in size distributions of DRG neuron profiles were detected before or after nerve injury. Injury-induced autotomy behavior developed much earlier and was more serious in KO mice. Although postnatal death or loss of DRG neurons is partially prevented by Bax deletion, this effect cannot interfere with long-term nerve injury-induced neuronal loss. The exaggerated self-amputation behavior observed in the mutant mice indicates that Bax deficiency may enhance the development of spontaneous pain following nerve injury.

Identity and function of a cardiac mitochondrial small conductance Ca2+-activated K+ channel splice variant

PubMed Central

Yang, MeiYing; Camara, Amadou K.S.; Aldakkak, Mohammed; Kwok, Wai-Meng; Stowe, David F.

2017-01-01

We provide evidence for location and function of a small conductance, Ca2+-activated K+ (SKCa) channel isoform 3 (SK3) in mitochondria (m) of guinea pig, rat and human ventricular myocytes. SKCa agonists protected isolated hearts and mitochondria against ischemia/reperfusion (IR) injury; SKCa antagonists worsened IR injury. Intravenous infusion of a SKCa channel agonist/antagonist, respectively, in intact rats was effective in reducing/enhancing regional infarct size induced by coronary artery occlusion. Localization of SK3 in mitochondria was evidenced by Western blot of inner mitochondrial membrane, immunocytochemical staining of cardiomyocytes, and immunogold labeling of isolated mitochondria. We identified a SK3 splice variant in guinea pig (SK3.1, aka SK3a) and human ventricular cells (SK3.2) by amplifying mRNA, and show mitochondrial expression in mouse atrial tumor cells (HL-1) by transfection with full length and truncated SK3.1 protein. We found that the Nterminus is not required for mitochondrial trafficking but the C-terminus beyond the Ca2+ calmodulin binding domain is required for Ca2+ sensing to induce mK+ influx and/or promote mitochondrial localization. In isolated guinea pig mitochondria and in SK3 overexpressed HL-1 cells, mK+ influx was driven by adding CaCl2. Moreover, there was a greater fall in membrane potential (ΔΨm), and enhanced cell death with simulated cell injury after silencing SK3.1 with siRNA. Although SKCa channel opening protects the heart and mitochondria against IR injury, the mechanism for favorable bioenergetics effects resulting from SKCa channel opening remains unclear. SKCa channels could play an essential role in restraining cardiac mitochondria from inducing oxidative stress-induced injury resulting from mCa2+ overload. PMID:28342809

No improvement of neuronal metabolism in the reperfusion phase with melatonin treatment after hypoxic-ischemic brain injury in the neonatal rat.

PubMed

Berger, Hester R; Morken, Tora Sund; Vettukattil, Riyas; Brubakk, Ann-Mari; Sonnewald, Ursula; Widerøe, Marius

2016-01-01

Mitochondrial impairment is a key feature underlying neonatal hypoxic-ischemic (HI) brain injury and melatonin is potentially neuroprotective through its effects on mitochondria. In this study, we have used (1) H and (13) C NMR spectroscopy after injection of [1-(13) C]glucose and [1,2-(13) C]acetate to examine neuronal and astrocytic metabolism in the early reperfusion phase after unilateral HI brain injury in 7-day-old rat pups, exploring the effects of HI on mitochondrial function and the potential protective effects of melatonin on brain metabolism. One hour after hypoxia-ischemia, astrocytic metabolism was recovered and glycolysis was normalized, whereas mitochondrial metabolism in neurons was clearly impaired. Pyruvate carboxylation was also lower in both hemispheres after HI. The transfer of glutamate from neurons to astrocytes was higher whereas the transfer of glutamine from astrocytes to neurons was lower 1 h after HI in the contralateral hemisphere. Neuronal metabolism was equally affected in pups treated with melatonin (10 mg/kg) immediately after HI as in vehicle treated pups indicating that the given dose of melatonin was not capable of protecting the neuronal mitochondria in this early phase after HI brain injury. However, any beneficial effects of melatonin might have been masked by modulatory effects of the solvent dimethyl sulfoxide on cerebral metabolism. Neuronal and astrocytic metabolism was examined by (13) C and (1) H NMR spectroscopy in the early reperfusion phase after unilateral hypoxic-ischemic brain injury and melatonin treatment in neonatal rats. One hour after hypoxia-ischemia astrocytic mitochondrial metabolism had recovered and glycolysis was normalized, whereas mitochondrial metabolism in neurons was impaired. Melatonin treatment did not show a protective effect on neuronal metabolism. © 2015 International Society for Neurochemistry.

Ginsenoside Rd attenuates myocardial ischemia/reperfusion injury via Akt/GSK-3β signaling and inhibition of the mitochondria-dependent apoptotic pathway.

PubMed

Wang, Yang; Li, Xu; Wang, Xiaoliang; Lau, Waynebond; Wang, Yajing; Xing, Yuan; Zhang, Xing; Ma, Xinliang; Gao, Feng

2013-01-01

Evidence suggests Ginsenoside Rd (GSRd), a biologically active extract from the medical plant Panax Ginseng, exerts antioxidant effect, decreasing reactive oxygen species (ROS) formation. Current study determined the effect of GSRd on myocardial ischemia/reperfusion (MI/R) injury (a pathological condition where ROS production is significantly increased) and investigated the underlying mechanisms. The current study utilized an in vivo rat model of MI/R injury and an in vitro neonatal rat cardiomyocyte (NRC) model of simulated ischemia/reperfusion (SI/R) injury. Infarct size was measured by Evans blue/TTC double staining. NRC injury was determined by MTT and lactate dehydrogenase (LDH) leakage assay. ROS accumulation and apoptosis were assessed by flow cytometry. Mitochondrial membrane potential (MMP) was determined by 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetrathylbenzimidazol carbocyanine iodide (JC-1). Cytosolic translocation of mitochondrial cytochrome c and expression of caspase-9, caspase-3, Bcl-2 family proteins, and phosphorylated Akt and GSK-3β were determined by western blot. Pretreatment with GSRd (50 mg/kg) significantly augmented rat cardiac function, as evidenced by increased left ventricular ejection fraction (LVEF) and ±dP/dt. GSRd reduced myocardial infarct size, apoptotic cell death, and blood creatine kinase/lactate dehydrogenase levels after MI/R. In NRCs, GSRd (10 µM) inhibited SI/R-induced ROS generation (P<0.01), decreased cellular apoptosis, stabilized the mitochondrial membrane potential (MMP), and attenuated cytosolic translocation of mitochondrial cytochrome c. GSRd inhibited activation of caspase-9 and caspase-3, increased the phosphorylated Akt and GSK-3β, and increased the Bcl-2/Bax ratio. Together, these data demonstrate GSRd mediated cardioprotective effect against MI/R-induced apoptosis via a mitochondrial-dependent apoptotic pathway.

Minoxidil attenuates ischemia-induced apoptosis in cultured neonatal rat cardiomyocytes.

PubMed

Takatani, Tomoka; Takahashi, Kyoko; Jin, Chengshi; Matsuda, Takahisa; Cheng, Xinyao; Ito, Takashi; Azuma, Junichi

2004-06-01

The effects of minoxidil (a mitochondrial K+(ATP) channel opener) on ischemia-induced necrosis and apoptosis were examined using a cardiomyocyte model of simulated ischemia, since mitochondrial K+(ATP) channel openers have been suggested to be involved in the mechanisms of cardioprotective action against ischemia/reperfusion injury. In the absence of minoxidil, simulated ischemia led to cellular release of creatine phosphokinase (CPK), morphologic degeneration, and beating cessation within 24 to 72 hours. Based on the Hoechst 33258 staining pattern, a significant number of cells placed in sealed flasks underwent apoptosis. Myocytes treated with 5 microM of minoxidil failed to alter the degree of ischemia-induced CPK loss for 48 to 72 hours. However, minoxidil treatment prevented the loss of beating function in many of the ischemic cells, and attenuated the decline in intracellular ATP content after a 48-hour ischemic incubation. The number of nuclear fragmentation was significantly reduced in minoxidil-treated cells after a 72-hour ischemic insult compared with untreated ischemic cells. This effect was blocked by the mitochondrial K+(ATP) channel antagonist 5-HD. The data suggest that minoxidil renders the cell resistant to ischemia-induced necrosis and apoptosis. The beneficial effects of minoxidil appear to be related to the opening of mitochondrial K+(ATP) channels.

Optical imaging of tissue mitochondrial redox state in intact rat lungs in two models of pulmonary oxidative stress

PubMed Central

Sepehr, Reyhaneh; Staniszewski, Kevin; Maleki, Sepideh; Jacobs, Elizabeth R.; Audi, Said

2012-01-01

Abstract. Ventilation with enhanced fractions of O2 (hyperoxia) is a common and necessary treatment for hypoxemia in patients with lung failure, but prolonged exposure to hyperoxia causes lung injury. Ischemia-reperfusion (IR) injury of lung tissue is common in lung transplant or crush injury to the chest. These conditions are associated with apoptosis and decreased survival of lung tissue. The objective of this work is to use cryoimaging to evaluate the effect of exposure to hyperoxia and IR injury on lung tissue mitochondrial redox state in rats. The autofluorescent mitochondrial metabolic coenzymes nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are electron carriers in ATP generation. These intrinsic fluorophores were imaged for rat lungs using low-temperature fluorescence imaging (cryoimaging). Perfused lungs from four groups of rats were studied: normoxia (control), control perfused with an mitochondrial complex IV inhibitor (potassium cyanide, KCN), rats exposed to hyperoxia (85% O2) for seven days, and from rats subjected to lung IR in vivo 24 hours prior to study. Each lung was sectioned sequentially in the transverse direction, and the images were used to reconstruct a three-dimensional (3-D) rendering. In KCN perfused lungs the respiratory chain was more reduced, whereas hyperoxic and IR lung tissue have a more oxidized respiratory chain than control lung tissue, consistent with previously measured mitochondrial dysfunction in both hyperoxic and IR lungs. PMID:22559688

Renal transplantation induces mitochondrial uncoupling, increased kidney oxygen consumption, and decreased kidney oxygen tension.

PubMed

Papazova, Diana A; Friederich-Persson, Malou; Joles, Jaap A; Verhaar, Marianne C

2015-01-01

Hypoxia is an acknowledged pathway to renal injury and ischemia-reperfusion (I/R) and is known to reduce renal oxygen tension (Po2). We hypothesized that renal I/R increases oxidative damage and induces mitochondrial uncoupling, resulting in increased oxygen consumption and hence kidney hypoxia. Lewis rats underwent syngenic renal transplantation (TX) and contralateral nephrectomy. Controls were uninephrectomized (1K-CON) or left untreated (2K-CON). After 7 days, urinary excretion of protein and thiobarbituric acid-reactive substances were measured, and after 14 days glomerular filtration rate (GFR), renal blood flow, whole kidney Qo2, cortical Po2, kidney cortex mitochondrial uncoupling, renal oxidative damage, and tubulointerstitial injury were assessed. TX, compared with 1K-CON, resulted in mitochondrial uncoupling mediated via uncoupling protein-2 (16 ± 3.3 vs. 0.9 ± 0.4 pmol O2 · s(-1)· mg protein(-1), P < 0.05) and increased whole kidney Qo2 (55 ± 16 vs. 33 ± 10 μmol O2/min, P < 0.05). Corticomedullary Po2 was lower in TX compared with 1K-CON (30 ± 13 vs. 47 ± 4 μM, P < 0.05) whereas no significant difference was observed between 2K-CON and 1K-CON rats. Proteinuria, oxidative damage, and the tubulointerstitial injury score were not significantly different in 1K-CON and TX. Treatment of donors for 5 days with mito-TEMPO reduced mitochondrial uncoupling but did not affect renal hemodynamics, Qo2, Po2, or injury. Collectively, our results demonstrate increased mitochondrial uncoupling as an early event after experimental renal transplantation associated with increased oxygen consumption and kidney hypoxia in the absence of increases in markers of damage. Copyright © 2015 the American Physiological Society.

Renal Mitochondrial Response to Low Temperature in Non-Hibernating and Hibernating Species.

PubMed

Dugbartey, George J; Hardenberg, Maarten C; Kok, Wendelinde F; Boerema, Ate S; Carey, Hannah V; Staples, James F; Henning, Robert H; Bouma, Hjalmar R

2017-09-20

Therapeutic hypothermia is commonly applied to limit ischemic injury in organ transplantation, during cardiac and brain surgery and after cardiopulmonary resuscitation. In these procedures, the kidneys are particularly at risk for ischemia/reperfusion injury (IRI), likely due to their high rate of metabolism. Although hypothermia mitigates ischemic kidney injury, it is not a panacea. Residual mitochondrial failure is believed to be a key event triggering loss of cellular homeostasis, and potentially cell death. Subsequent rewarming generates large amounts of reactive oxygen species that aggravate organ injury. Recent Advances: Hibernators are able to withstand periods of profoundly reduced metabolism and body temperature ("torpor"), interspersed by brief periods of rewarming ("arousal") without signs of organ injury. Specific adaptations allow maintenance of mitochondrial homeostasis, limit oxidative stress, and protect against cell death. These adaptations consist of active suppression of mitochondrial function and upregulation of anti-oxidant enzymes and anti-apoptotic pathways. Unraveling the precise molecular mechanisms that allow hibernators to cycle through torpor and arousal without precipitating organ injury may translate into novel pharmacological approaches to limit IRI in patients. Although the precise signaling routes involved in natural hibernation are not yet fully understood, torpor-like hypothermic states with increased resistance to ischemia/reperfusion can be induced pharmacologically by 5'-adenosine monophosphate (5'-AMP), adenosine, and hydrogen sulfide (H 2 S) in non-hibernators. In this review, we compare the molecular effects of hypothermia in non-hibernators with natural and pharmacologically induced torpor, to delineate how safe and reversible metabolic suppression may provide resistance to renal IRI. Antioxid. Redox Signal. 27, 599-617.

Characterization of mitochondrial injury after cardiac arrest (COMICA).

PubMed

Donnino, Michael W; Liu, Xiaowen; Andersen, Lars W; Rittenberger, Jon C; Abella, Benjamin S; Gaieski, David F; Ornato, Joseph P; Gazmuri, Raúl J; Grossestreuer, Anne V; Cocchi, Michael N; Abbate, Antonio; Uber, Amy; Clore, John; Peberdy, Mary Anne; Callaway, Clifton W

2017-04-01

Mitochondrial injury post-cardiac arrest has been described in pre-clinical settings but the extent to which this injury occurs in humans remains largely unknown. We hypothesized that increased levels of mitochondrial biomarkers would be associated with mortality and neurological morbidity in post-cardiac arrest subjects. We performed a prospective multicenter study of post-cardiac arrest subjects. Inclusion criteria were comatose adults who suffered an out-of-hospital cardiac arrest. Mitochondrial biomarkers were measured at 0, 12, 24, 36 and 48h after return of spontaneous circulation as well as in healthy controls. Out of 111 subjects enrolled, 102 had evaluable samples at 0h. Cardiac arrest subjects had higher baseline cytochrome c levels compared to controls (2.18ng/mL [0.74, 7.74] vs. 0.16ng/mL [0.03, 0.91], p<0.001), and subjects who died had higher 0h cytochrome c levels compared to survivors (3.66ng/mL [1.40, 14.9] vs. 1.27ng/mL [0.16, 2.37], p<0.001). There were significantly higher Ribonuclease P (RNaseP) (3.3 [1.2, 5.7] vs. 1.2 [0.8, 1.2], p<0.001) and Beta-2microglobulin (B2M) (12.0 [1.0, 22.9], vs. 0.6 [0.6, 1.3], p<0.001) levels in cardiac arrest subjects at baseline compared to the control subjects. There were no differences between survivors and non-survivors for mitochondrial DNA, nuclear DNA, or cell free DNA. Cytochrome c was increased in post- cardiac arrest subjects compared to controls, and in post-cardiac arrest non-survivors compared to survivors. Nuclear DNA and cell free DNA was increased in plasma of post-cardiac arrest subjects. There were no differences in mitochondrial DNA, nuclear DNA, or cell free DNA between survivors and non-survivors. Mitochondrial injury markers showed mixed results in the post-cardiac arrest period. Future research needs to investigate these differences. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of Mitochondrial Injury after Cardiac Arrest (COMICA)

PubMed Central

Donnino, Michael W.; Liu, Xiaowen; Andersen, Lars W.; Rittenberger, Jon C.; Abella, Benjamin S.; Gaieski, David F.; Ornato, Joseph P.; Gazmuri, Raúl J.; Grossestreur, Anne V.; Cocchi, Michaen N.; Abbate, Antonio; Uber, Amy; Clore, John; Peberdy, Mary Anne; Callaway, Clifton

2017-01-01

Introduction Mitochondrial injury post-cardiac arrest has been described in pre-clinical settings but the extent to which this injury occurs in humans remains largely unknown. We hypothesized that increased levels of mitochondrial biomarkers would be associated with mortality and neurological morbidity in post-cardiac arrest subjects. Methods We performed a prospective multicenter study of post-cardiac arrest subjects. Inclusion criteria were comatose adults who suffered an out-of-hospital cardiac arrest. Mitochondrial biomarkers were measured at 0, 12, 24, 36 and 48 hours after return of spontaneous circulation as well as in healthy controls. Results Out of 111 subjects enrolled, 102 had evaluable samples at 0 hours. Cardiac arrest subjects had higher baseline cytochrome c levels compared to controls (2.18 ng/mL [0.74, 7.74] vs. 0.16 ng/mL [0.03, 0.91], p<0.001), and subjects who died had higher 0 hours cytochrome c levels compared to survivors (3.66 ng/mL [1.40, 14.9] vs. 1.27 ng/mL [0.16, 2.37], p<0.001). There were significantly higher RNAase P (3.3 [1.2, 5.7] vs. 1.2 [0.8, 1.2], p<0.001) and B2M (12.0 [1.0, 22.9], vs. 0.6 [0.6, 1.3], p<0.001) levels in cardiac arrest subjects at baseline compared to the control subjects. There were no differences between survivors and non-survivors for mitochondrial DNA, nuclear DNA, or cell free DNA. Conclusions Cytochrome C was increased in post-cardiac arrest subjects compared to controls, and in post-cardiac arrest non-survivors compared to survivors. Nuclear DNA and cell free DNA was increased in plasma of post-cardiac arrest subjects. There were no differences in mitochondrial DNA, nuclear DNA, or cell free DNA between survivors and non-survivors. Mitochondrial injury markers showed mixed results in post-arrest period. Future research needs to investigate these differences. PMID:28126408

Improvement of liver injury and survival by JNK2 and iNOS deficiency in liver transplants from cardiac death mice.

PubMed

Liu, Qinlong; Rehman, Hasibur; Krishnasamy, Yasodha; Schnellmann, Rick G; Lemasters, John J; Zhong, Zhi

2015-07-01

Inclusion of liver grafts from cardiac death donors (CDD) would increase the availability of donor livers but is hampered by a higher risk of primary non-function. Here, we seek to determine mechanisms that contribute to primary non-function of liver grafts from CDD with the goal to develop strategies for improved function and outcome, focusing on c-Jun-N-terminal kinase (JNK) activation and mitochondrial depolarization, two known mediators of graft failure. Livers explanted from wild-type, inducible nitric oxide synthase knockout (iNOS(-/-)), JNK1(-/-) or JNK2(-/-) mice after 45-min aorta clamping were implanted into wild-type recipients. Mitochondrial depolarization was detected by intravital confocal microscopy in living recipients. After transplantation of wild-type CDD livers, graft iNOS expression and 3-nitrotyrosine adducts increased, but hepatic endothelial NOS expression was unchanged. Graft injury and dysfunction were substantially higher in CDD grafts than in non-CDD grafts. iNOS deficiency and inhibition attenuated injury and improved function and survival of CDD grafts. JNK1/2 and apoptosis signal-regulating kinase-1 activation increased markedly in wild-type CDD grafts, which was blunted by iNOS deficiency. JNK inhibition and JNK2 deficiency, but not JNK1 deficiency, decreased injury and improved function and survival of CDD grafts. Mitochondrial depolarization and binding of phospho-JNK2 to Sab, a mitochondrial protein linked to the mitochondrial permeability transition, were higher in CDD than in non-CDD grafts. iNOS deficiency, JNK inhibition and JNK2 deficiency all decreased mitochondrial depolarization and blunted ATP depletion in CDD grafts. JNK inhibition and deficiency did not decrease 3-nitrotyrosine adducts in CDD grafts. The iNOS-JNK2-Sab pathway promotes CDD graft failure via increased mitochondrial depolarization, and is an attractive target to improve liver function and survival in CDD liver transplantation recipients. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun

Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake wasmore » measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect by inhibiting the MCU.« less

Dynamin-Related Protein 1 as a therapeutic target in cardiac arrest

PubMed Central

Sharp, Willard W.

2015-01-01

Despite improvements in cardiopulmonary resuscitation (CPR) quality, defibrillation technologies, and implementation of therapeutic hypothermia, less than 10% of out-of-hospital cardiac arrest (OHCA) victims survive to hospital discharge. New resuscitation therapies have been slow to develop, in part, because the pathophysiologic mechanisms critical for resuscitation are not understood. During cardiac arrest, systemic cessation of blood flow results in whole body ischemia. CPR, and the restoration of spontaneous circulation (ROSC), both result in immediate reperfusion injury of the heart that is characterized by severe contractile dysfunction. Unlike diseases of localized ischemia/reperfusion (IR) injury (myocardial infarction and stroke), global IR injury of organs results in profound organ dysfunction with far shorter ischemic times. The two most commonly injured organs following cardiac arrest resuscitation, the heart and brain, are critically dependent on mitochondrial function. New insights into mitochondrial dynamics and the role of the mitochondrial fission protein Dynamin-related protein 1 (Drp1) in apoptosis have made targeting these mechanisms attractive for IR therapy. In animal models, inhibiting Drp1 following IR injury or cardiac arrest confers protection to both the heart and brain. In this review, the relationship of the major mitochondrial fission protein Drp1 to ischemic changes in the heart and its targeting as a new therapeutic target following cardiac arrest are discussed. PMID:25659608

Inhibitor of apoptosis signal-regulating kinase 1 protects against acetaminophen-induced liver injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Yuchao; Ramachandran, Anup; Breckenridge, David G.

Metabolic activation and oxidant stress are key events in the pathophysiology of acetaminophen (APAP) hepatotoxicity. The initial mitochondrial oxidative stress triggered by protein adduct formation is amplified by c-jun-N-terminal kinase (JNK), resulting in mitochondrial dysfunction and ultimately cell necrosis. Apoptosis signal-regulating kinase 1 (ASK1) is considered the link between oxidant stress and JNK activation. The objective of the current study was to assess the efficacy and mechanism of action of the small-molecule ASK1 inhibitor GS-459679 in a murine model of APAP hepatotoxicity. APAP (300 mg/kg) caused extensive glutathione depletion, JNK activation and translocation to the mitochondria, oxidant stress and livermore » injury as indicated by plasma ALT activities and area of necrosis over a 24 h observation period. Pretreatment with 30 mg/kg of GS-459679 almost completely prevented JNK activation, oxidant stress and injury without affecting the metabolic activation of APAP. To evaluate the therapeutic potential of GS-459679, mice were treated with APAP and then with the inhibitor. Given 1.5 h after APAP, GS-459679 was still protective, which was paralleled by reduced JNK activation and p-JNK translocation to mitochondria. However, GS-459679 treatment was not more effective than N-acetylcysteine, and the combination of GS-459679 and N-acetylcysteine exhibited similar efficacy as N-acetylcysteine monotherapy, suggesting that GS-459769 and N-acetylcysteine affect the same pathway. Importantly, inhibition of ASK1 did not impair liver regeneration as indicated by PCNA staining. In conclusion, the ASK1 inhibitor GS-459679 protected against APAP toxicity by attenuating JNK activation and oxidant stress in mice and may have therapeutic potential for APAP overdose patients. - Highlights: • Two ASK1 inhibitors protected against acetaminophen-induced liver injury. • The ASK1 inhibitors protect when used as pre- or post-treatment. • Protection by ASK1 inhibitor is not due to inhibition of APAP metabolism. • The ASK1 inhibitor prevents JNK activation and translocation to mitochondria. • Treatment with ASK1 inhibitors does not impair liver regeneration after APAP.« less

Polyenylphosphatidylcholine attenuates alcohol-induced fatty liver and hyperlipemia in rats.

PubMed

Navder, K P; Baraona, E; Lieber, C S

1997-09-01

Chronic administration of a soybean-derived polyenylphosphatidylcholine (PPC) extract prevents the development of cirrhosis in alcohol-fed baboons. To assess whether this phospholipid also affects earlier changes induced by alcohol consumption (such as fatty liver and hyperlipemia), 28 male rat littermates were pair-fed liquid diets containing 36% of energy either as ethanol or as additional carbohydrate for 21 d, and killed 90 min after intragastric administration of the corresponding diets. Half of the rats were given PPC (3 g/l), whereas the other half received the same amount of linoleate (as safflower oil) and choline (as bitartrate salt). PPC did not affect diet or alcohol consumption [15.4 +/- 0.5 G/(kg.d)], but the ethanol-induced hepatomegaly and the hepatic accumulation of lipids (principally triglycerides and cholesterol esters) and proteins were about half those in rats not given PPC. The ethanol-induced postprandial hyperlipemia was lower with PPC than without, despite an enhanced fat absorption and no difference in the level of plasma free fatty acids. The attenuation of fatty liver and hyperlipemia was associated with correction of the ethanol-induced inhibition of mitochondrial oxidation of palmitoyl-1-carnitine and the depression of cytochrome oxidase activity, as well as the increases in activity of serum glutamate dehydrogenase and aminotransferases. Thus, PPC attenuates early manifestations of alcohol toxicity, at least in part, by improving mitochondrial injury. These beneficial effects of PPC at the initial stages of alcoholic liver injury may prevent or delay the progression to more advanced forms of alcoholic liver disease.

Isoflurane postconditioning prevents opening of the mitochondrial permeability transition pore through inhibition of glycogen synthase kinase 3beta.

PubMed

Feng, Jianhua; Lucchinetti, Eliana; Ahuja, Preeti; Pasch, Thomas; Perriard, Jean-Claude; Zaugg, Michael

2005-11-01

Postischemic administration of volatile anesthetics activates reperfusion injury salvage kinases and decreases myocardial damage. However, the mechanisms underlying anesthetic postconditioning are unclear. Isolated perfused rat hearts were exposed to 40 min of ischemia followed by 1 h of reperfusion. Anesthetic postconditioning was induced by 15 min of 2.1 vol% isoflurane (1.5 minimum alveolar concentration) administered at the onset of reperfusion. In some experiments, atractyloside (10 microm), a mitochondrial permeability transition pore (mPTP) opener, and LY294002 (15 microm), a phosphatidylinositol 3-kinase inhibitor, were coadministered with isoflurane. Western blot analysis was used to determine phosphorylation of protein kinase B/Akt and its downstream target glycogen synthase kinase 3beta after 15 min of reperfusion. Myocardial tissue content of nicotinamide adenine dinucleotide served as a marker for mPTP opening. Accumulation of MitoTracker Red 580 (Molecular Probes, Invitrogen, Basel, Switzerland) was used to visualize mitochondrial function. Anesthetic postconditioning significantly improved functional recovery and decreased infarct size (36 +/- 1% in unprotected hearts vs. 3 +/- 2% in anesthetic postconditioning; P < 0.05). Isoflurane-mediated protection was abolished by atractyloside and LY294002. LY294002 inhibited isoflurane-induced phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta and opened mPTP as determined by nicotinamide adenine dinucleotide measurements. Atractyloside, a direct opener of the mPTP, did not inhibit phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta by isoflurane but reversed isoflurane-mediated cytoprotection. Microscopy showed accumulation of the mitochondrial tracker in isoflurane-protected functional mitochondria but no staining in mitochondria of unprotected hearts. Anesthetic postconditioning by isoflurane effectively protects against reperfusion damage by preventing opening of the mPTP through inhibition of glycogen synthase kinase 3beta.

Gradual changes in permeability of inner mitochondrial membrane precede the mitochondrial permeability transition.

PubMed

Balakirev, M Y; Zimmer, G

1998-08-01

Some compounds are known to induce solute-nonselective permeability of the inner mitochondrial membrane (IMM) in Ca2+-loaded mitochondria. Existing data suggest that this process, following the opening of a mitochondrial permeability transition pore, is preceded by different solute-selective permeable states of IMM. At pH 7, for instance, the K0.5 for Ca2+-induced pore opening is 16 microM, a value 80-fold above a therapeutically relevant shift of intracellular Ca2+ during ischemia in vivo. The present work shows that in the absence of Ca2+, phenylarsine oxide and tetraalkyl thiuram disulfides (TDs) are able to induce a complex sequence of IMM permeability changes. At first, these agents activated an electrogenic K+ influx into the mitochondria. This K+-specific pathway had K0.5 = 35 mM for K+ and was inhibited by bromsulfalein with Ki = 2.5 microM. The inhibitors of mitochondrial KATP channel, ATP and glibenclamide, did not inhibit K+ transport via this pathway. Moreover, 50 microM glibenclamide induced by itself K+ influx into the mitochondria. After the increase in K+ permeability of IMM, mitochondria become increasingly permeable to protons. Mechanisms of H+ leak and nonselective permeability increase could also be different depending on the type of mitochondrial permeability transition (MPT) inducer. Thus, permeabilization of mitochondria induced by phenylarsine oxide was fully prevented by ADP and/or cyclosporin A, whereas TD-induced membrane alterations were insensitive toward these inhibitors. It is suggested that MPT in vivo leading to irreversible apoptosis is irrelevant in reversible ischemia/reperfusion injury. Copyright 1998 Academic Press.

Squid ink polysaccharide prevents autophagy and oxidative stress affected by cyclophosphamide in Leydig cells of mice: a pilot study

PubMed Central

Gu, Yi-Peng; Yang, Xiao-Mei; Duan, Zhen-Hua; Shang, Jiang-Hua; Luo, Ping; Xiao, Wei; Zhang, Da-Yan; Liu, Hua-Zhong

2017-01-01

Objective(s): The aim of this study was to explore the effects of Squid ink polysaccharide (SIP) on prevention of autophagy and oxidative stress induced by cyclophosphamide (CP) in Leydig cells of mice. Materials and Methods: Examination of reproductive organ exponents, abnormal sperm rate, activities of superoxide dismutase (SOD), catalase (CAT), contents of malondialdehyde (MDA), and histological structure were performed to detect the optimal dose of SIP against oxidative stress damage in vivo, and autophagy-associated protein LC3 and Beclin-1 were examined by immunofluorescence, and their expression was detected by Western blot analysis. Leydig cells ultrastructural changes were observed by transmission fluorescent microscope. Results: SIP significantly inhibited sperm aberration, histological structure and injury of seminiferous tubules caused by CP, as well as the antioxidant activity of SOD and CAT were increased; contents of MDA were decreased. The optimal dose of SIP for prevention of oxidative stress injury by CP was 80 mg/kg. In addition, LC3 and Beclin-1 fluorescent granules were much less in the Leydig cell layer after treatment via SIP compared with the CP-treated group, and the expression levels of LC3 and Beclin-1 were also decreased. Furthermore, characteristics of cell autophagy such as mitochondrial swelling, autophagic vacuoles, and chromatin pyknosis were observed in CP-treated Leydig cells, but SIP could effectively weaken injury of Leydig cell ultrastructure by CP. Conclusion: SIP, as an antioxidant, prevents the cytoskeleton damage through up-regulation antioxidant capacity and inhibition autophagy caused by CP. PMID:29299195

Levosimendan: A Cardiovascular Drug to Prevent Liver Ischemia-Reperfusion Injury?

PubMed Central

Fulop, Andras; Rosero, Oliver; Garbaisz, David; Turoczi, Zsolt; Lotz, Gabor; Rakonczay, Zoltan; Balla, Zsolt; Hegedus, Viktor; Harsanyi, Laszlo; Szijarto, Attila

2013-01-01

Introduction Temporary occlusion of the hepatoduodenal ligament leads to an ischemic-reperfusion (IR) injury in the liver. Levosimendan is a new positive inotropic drug, which induces preconditioning-like adaptive mechanisms due to opening of mitochondrial KATP channels. The aim of this study was to examine possible protective effects of levosimendan in a rat model of hepatic IR injury. Material and Methods Levosimendan was administered to male Wistar rats 1 hour (early pretreatment) or 24 hours (late pretreatment) before induction of 60-minute segmental liver ischemia. Microcirculation of the liver was monitored by laser Doppler flowmeter. After 24 hours of reperfusion, liver and blood samples were taken for histology, immuno- and enzyme-histochemistry (TUNEL; PARP; NADH-TR) as well as for laboratory tests. Furthermore, liver antioxidant status was assessed and HSP72 expression was measured. Results In both groups pretreated with levosimendan, significantly better hepatic microcirculation was observed compared to respective IR control groups. Similarly, histological damage was also reduced after levosimendan administration. This observation was supported by significantly lower activities of serum ALT (pearly = 0.02; plate = 0.005), AST (pearly = 0.02; plate = 0.004) and less DNA damage by TUNEL test (pearly = 0.05; plate = 0.034) and PAR positivity (pearly = 0.02; plate = 0.04). Levosimendan pretreatment resulted in significant improvement of liver redox homeostasis. Further, significantly better mitochondrial function was detected in animals receiving late pretreatment. Finally, HSP72 expression was increased by IR injury, but it was not affected by levosimendan pretreatment. Conclusion Levosimendan pretreatment can be hepatoprotective and it could be useful before extensive liver resection. PMID:24040056

Nanoparticle-Mediated Delivery of Mitochondrial Division Inhibitor 1 to the Myocardium Protects the Heart From Ischemia-Reperfusion Injury Through Inhibition of Mitochondria Outer Membrane Permeabilization: A New Therapeutic Modality for Acute Myocardial Infarction.

PubMed

Ishikita, Ayako; Matoba, Tetsuya; Ikeda, Gentaro; Koga, Jun-Ichiro; Mao, Yajing; Nakano, Kaku; Takeuchi, Osamu; Sadoshima, Junichi; Egashira, Kensuke

2016-07-22

Mitochondria-mediated cell death plays a critical role in myocardial ischemia-reperfusion (IR) injury. We hypothesized that nanoparticle-mediated drug delivery of mitochondrial division inhibitor 1 (Mdivi1) protects hearts from IR injury through inhibition of mitochondria outer membrane permeabilization (MOMP), which causes mitochondrial-mediated cell death. We formulated poly (lactic-co-glycolic acid) nanoparticles containing Mdivi1 (Mdivi1-NP). We recently demonstrated that these nanoparticles could be successfully delivered to the cytosol and mitochondria of cardiomyocytes under H2O2-induced oxidative stress that mimicked IR injury. Pretreatment with Mdivi1-NP ameliorated H2O2-induced cell death in rat neonatal cardiomyocytes more potently than Mdivi1 alone, as indicated by a lower estimated half-maximal effective concentration and greater maximal effect on cell survival. Mdivi1-NP treatment of Langendorff-perfused mouse hearts through the coronary arteries at the time of reperfusion reduced infarct size after IR injury more effectively than Mdivi1 alone. Mdivi1-NP treatment also inhibited Drp1-mediated Bax translocation to the mitochondria and subsequent cytochrome c leakage into the cytosol, namely, MOMP, in mouse IR hearts. MOMP inhibition was also observed in cyclophilin D knockout (CypD-KO) mice, which lack the mitochondrial permeability transition pore (MPTP) opening. Intravenous Mdivi1-NP treatment in vivo at the time of reperfusion reduced IR injury in wild-type and CypD-KO mice, but not Bax-KO mice. Mdivi1-NP treatment reduced IR injury through inhibition of MOMP, even in the absence of a CypD/MPTP opening. Thus, nanoparticle-mediated drug delivery of Mdivi1 may be a novel treatment strategy for IR injury. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Water-soluble Coenzyme Q10 formulation (Q-ter) promotes outer hair cell survival in a guinea pig model of noise induced hearing loss (NIHL).

PubMed

Fetoni, Anna Rita; Piacentini, Roberto; Fiorita, Antonella; Paludetti, Gaetano; Troiani, Diana

2009-02-27

The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS) also in noise induced hearing loss (NIHL) and anti-oxidants and free-radicals scavengers have been shown to attenuate the damage. Coenzyme Q(10) (CoQ(10)) or ubiquinone has a bioenergetic role as a component of the mithocondrial respiratory chain, it inhibits mitochondrial lipid peroxidation, inducing ATP production and it is involved in ROS removal and prevention of oxidative stress-induced apoptosis. However the therapeutic application of CoQ(10) is limited by the lack of solubility and poor bio- availability, therefore it is a challenge to improve its water solubility in order to ameliorate the efficacy in tissues and fluids. This study was conducted in a model of acoustic trauma in the guinea pig where the effectiveness of CoQ(10) was compared with a soluble formulation of CoQ(10) (multicomposite CoQ(10) Terclatrate, Q-ter) given intraperitoneally 1 h before and once daily for 3 days after pure tone noise exposure (6 kHz for 1 h at 120 dB SPL). Functional and morphological studies were carried out by measuring auditory brainstem responses, scanning electron microscopy for hair cell loss count, active caspase 3 staining and terminal deoxynucleotidyl transferase-mediated dUTP labelling assay in order to identify initial signs of apoptosis. Treatments decreased active caspase 3 expression and the number of apoptotic cells, but animals injected with Q-ter showed a greater degree of activity in preventing apoptosis and thus in improving hearing. These data confirm that solubility of Coenzyme Q(10) improves the ability of CoQ(10) in preventing oxidative injuries that result from mitochondrial dysfunction.

Melatonin and mitochondrial function during ischemia/reperfusion injury.

PubMed

Ma, Zhiqiang; Xin, Zhenlong; Di, Wencheng; Yan, Xiaolong; Li, Xiaofei; Reiter, Russel J; Yang, Yang

2017-11-01

Ischemia/reperfusion (IR) injury occurs in many organs and tissues, and contributes to morbidity and mortality worldwide. Melatonin, an endogenously produced indolamine, provides a strong defense against IR injury. Mitochondrion, an organelle for ATP production and a decider for cell fate, has been validated to be a crucial target for melatonin to exert its protection against IR injury. In this review, we first clarify the mechanisms underlying mitochondrial dysfunction during IR and melatonin's protection of mitochondria under this condition. Thereafter, special focus is placed on the protective actions of melatonin against IR injury in brain, heart, liver, and others. Finally, we explore several potential future directions of research in this area. Collectively, the information compiled here will serve as a comprehensive reference for the actions of melatonin in IR injury identified to date and will hopefully aid in the design of future research and increase the potential of melatonin as a therapeutic agent.

Inhibiting poly(ADP-ribose) polymerase: a potential therapy against oligodendrocyte death

PubMed Central

Veto, Sara; Acs, Peter; Bauer, Jan; Lassmann, Hans; Berente, Zoltan; Setalo, Gyorgy; Borgulya, Gabor; Sumegi, Balazs; Komoly, Samuel; Gallyas, Ferenc; Illes, Zsolt

2010-01-01

Oligodendrocyte loss and demyelination are major pathological hallmarks of multiple sclerosis. In pattern III lesions, inflammation is minor in the early stages, and oligodendrocyte apoptosis prevails, which appears to be mediated at least in part through mitochondrial injury. Here, we demonstrate poly(ADP-ribose) polymerase activation and apoptosis inducing factor nuclear translocation within apoptotic oligodendrocytes in such multiple sclerosis lesions. The same morphological and molecular pathology was observed in an experimental model of primary demyelination, induced by the mitochondrial toxin cuprizone. Inhibition of poly(ADP-ribose) polymerase in this model attenuated oligodendrocyte depletion and decreased demyelination. Poly(ADP-ribose) polymerase inhibition suppressed c-Jun N-terminal kinase and p38 mitogen-activated protein kinase phosphorylation, increased the activation of the cytoprotective phosphatidylinositol-3 kinase-Akt pathway and prevented caspase-independent apoptosis inducing factor-mediated apoptosis. Our data indicate that poly(ADP-ribose) polymerase activation plays a crucial role in the pathogenesis of pattern III multiple sclerosis lesions. Since poly(ADP-ribose) polymerase inhibition was also effective in the inflammatory model of multiple sclerosis, it may target all subtypes of multiple sclerosis, either by preventing oligodendrocyte death or attenuating inflammation. PMID:20157013

Assessment of hepatoprotective and nephroprotective potential of withaferin A on bromobenzene-induced injury in Swiss albino mice: possible involvement of mitochondrial dysfunction and inflammation.

PubMed

Vedi, Mahima; Sabina, Evan Prince

2016-10-01

Bromobenzene is a well-known environmental toxin which causes liver and kidney damage through CYP450-mediated bio-activation to generate reactive metabolites and, consequently, oxidative stress. The present study aimed to evaluate the possible protective role of withaferin A against bromobenzene-induced liver and kidney damage in mice. Withaferin A (10 mg/kg) was administered orally to the mice for 8 days before intragastric intubation of bromobenzene (10 mmol/kg). As results of this experiment, the levels of liver and kidney functional markers, lipid peroxidation, and cytokines (TNF-α and IL-1β) presented an increase and there was a decrease in anti-oxidant activity in the bromobenzene-treated group of mice. Pre-treatment with withaferin A not only significantly decreased the levels of liver and kidney functional markers and cytokines but also reduced oxidative stress, as evidenced by improved anti-oxidant status. In addition, the mitochondrial dysfunction shown through the decrease in the activities of mitochondrial enzymes and imbalance in the Bax/Bcl-2 expression in the livers and kidneys of bromobenzene-treated mice was effectively prevented by pre-administration of withaferin A. These results validated our conviction that bromobenzene caused liver and kidney damage via mitochondrial pathway and withaferin A provided significant protection against it. Thus, withaferin A may have possible usage in clinical liver and kidney diseases in which oxidative stress and mitochondrial dysfunction may be existent.

RNase1 prevents the damaging interplay between extracellular RNA and tumour necrosis factor-α in cardiac ischaemia/reperfusion injury.

PubMed

Cabrera-Fuentes, H A; Ruiz-Meana, M; Simsekyilmaz, S; Kostin, S; Inserte, J; Saffarzadeh, M; Galuska, S P; Vijayan, V; Barba, I; Barreto, G; Fischer, S; Lochnit, G; Ilinskaya, O N; Baumgart-Vogt, E; Böning, A; Lecour, S; Hausenloy, D J; Liehn, E A; Garcia-Dorado, D; Schlüter, K-D; Preissner, K T

2014-12-01

Despite optimal therapy, the morbidity and mortality of patients presenting with an acute myocardial infarction (MI) remain significant, and the initial mechanistic trigger of myocardial "ischaemia/reperfusion (I/R) injury" remains greatly unexplained. Here we show that factors released from the damaged cardiac tissue itself, in particular extracellular RNA (eRNA) and tumour-necrosis-factor α (TNF-α), may dictate I/R injury. In an experimental in vivo mouse model of myocardial I/R as well as in the isolated I/R Langendorff-perfused rat heart, cardiomyocyte death was induced by eRNA and TNF-α. Moreover, TNF-α promoted further eRNA release especially under hypoxia, feeding a vicious cell damaging cycle during I/R with the massive production of oxygen radicals, mitochondrial obstruction, decrease in antioxidant enzymes and decline of cardiomyocyte functions. The administration of RNase1 significantly decreased myocardial infarction in both experimental models. This regimen allowed the reduction in cytokine release, normalisation of antioxidant enzymes as well as preservation of cardiac tissue. Thus, RNase1 administration provides a novel therapeutic regimen to interfere with the adverse eRNA-TNF-α interplay and significantly reduces or prevents the pathological outcome of ischaemic heart disease.

Decreasing mitochondrial fission diminishes vascular smooth muscle cell migration and ameliorates intimal hyperplasia

PubMed Central

Wang, Li; Yu, Tianzheng; Lee, Hakjoo; O'Brien, Dawn K.; Sesaki, Hiromi; Yoon, Yisang

2015-01-01

Aims Vascular smooth muscle cell (VSMC) migration in response to arterial wall injury is a critical process in the development of intimal hyperplasia. Cell migration is an energy-demanding process that is predicted to require mitochondrial function. Mitochondria are morphologically dynamic, undergoing continuous shape change through fission and fusion. However, the role of mitochondrial morphology in VSMC migration is not well understood. The aim of the study is to understand how mitochondrial fission contributes to VSMC migration and provides its in vivo relevance in the mouse model of intimal hyperplasia. Methods and results In primary mouse VSMCs, the chemoattractant PDGF induced mitochondrial shortening through the mitochondrial fission protein dynamin-like protein 1 (DLP1)/Drp1. Perturbation of mitochondrial fission by expressing the dominant-negative mutant DLP1-K38A or by DLP1 silencing greatly decreased PDGF-induced lamellipodia formation and VSMC migration, indicating that mitochondrial fission is an important process in VSMC migration. PDGF induced an augmentation of mitochondrial energetics as well as ROS production, both of which were found to be necessary for VSMC migration. Mechanistically, the inhibition of mitochondrial fission induced an increase of mitochondrial inner membrane proton leak in VSMCs, abrogating the PDGF-induced energetic enhancement and an ROS increase. In an in vivo model of intimal hyperplasia, transgenic mice expressing DLP1-K38A displayed markedly reduced ROS levels and neointima formation in response to femoral artery wire injury. Conclusions Mitochondrial fission is an integral process in cell migration, and controlling mitochondrial fission can limit VSMC migration and the pathological intimal hyperplasia by altering mitochondrial energetics and ROS levels. PMID:25587046

Leaf extract of Rhus verniciflua Stokes protects dopaminergic neuronal cells in a rotenone model of Parkinson's disease.

PubMed

Kim, Seung; Park, Se-Eun; Sapkota, Kumar; Kim, Myung-Kon; Kim, Sung-Jun

2011-10-01

The present study investigated the neuroprotective effects of Rhus verniciflua Stokes (RVS) leaf extract on rotenone-induced apoptosis in human dopaminergic cells, SH-SY5Y. Cells were pretreated with RVS extract for 1 h then treated with vehicle or rotenone for 24 h. Cell viability, cell cytotoxicity, cell morphology and nuclear morphology were examined by MTT assay, lactate dehydrogenase release assay, phase contrast microscopy and staining with Hoechast 33342, respectively. Reactive oxygen species were measured by 2'7'-dichlorofluorescein diacetate and fragmented DNA was observed by TUNEL assay. Mitochondrial membrane potential was determined by Rhodamine 123. Pro-apoptotic and anti-apoptotic proteins and tyrosine hydroxylase were analysed by Western blotting. Results showed that RVS suppressed rotenone-induced reactive oxygen species generation, cellular injury and apoptotic cell death. RVS also prevented rotenone-mediated changes in Bax/Bcl-2 levels, mitochondrial membrane potential dissipation and Caspase 3 activation. Moreover, RVS pretreatment increased the tyrosine hydroxylase levels in SH-SY5Y cells. These findings demonstrate that RVS protects SH-SY5Y cells against rotenone-induced injury and suggest that RVS may have potential therapeutic value for neurodegenerative disease associated with oxidative stress. © 2011 The Authors. JPP © 2011 Royal Pharmaceutical Society.

Combined Salvianolic Acid B and Ginsenoside Rg1 Exerts Cardioprotection against Ischemia/Reperfusion Injury in Rats

PubMed Central

Deng, Yanping; Yang, Min; Xu, Feng; Zhang, Qian; Zhao, Qun; Yu, Haitao; Li, Defang; Zhang, Ge; Lu, Aiping; Cho, Kenka; Teng, Fukang; Wu, Peng; Wang, Linlin; Wu, Wanying; Liu, Xuan; Guo, De-an; Jiang, Baohong

2015-01-01

Lack of pharmacological strategies in clinics restricts the patient prognosis with myocardial ischemia/reperfusion (I/R) injury. The aim of this study was to evaluate the cardioprotection of combined salvianolic acid B (SalB) and ginsenoside Rg1 (Rg1) against myocardial I/R injury and further investigate the underlying mechanism. I/R injury was induced by coronary artery ligation for Wistar male rats and hypoxia/reoxygenation injury was induced on H9c2 cells. Firstly, the best ratio between SalB and Rg1was set as 2:5 based on their effects on heart function detected by hemodynamic measurement. Then SalB-Rg1 (2:5) was found to maintain mitochondrial membrane potential and resist apoptosis and necrosis in H9c2 cell with hypoxia/reoxygenation injury. Companying with same dose of SalB or Rg1 only, SalB-Rg1 showed more significant effects on down-regulation of myocardial infarct size, maintenance of myocardium structure, improvement on cardiac function, decrease of cytokine secretion including TNF-α, IL-1β, RANTES and sVCAM-1. Finally, the SalB-Rg1 improved the viability of cardiac myocytes other than cardiac fibroblasts in rats with I/R injury using flow cytometry. Our results revealed that SalB-Rg1 was a promising strategy to prevent myocardial I/R injury. PMID:26280455

Mitochondrial role in cell aging

NASA Technical Reports Server (NTRS)

Miquel, J.; Fleming, J.; Economos, A. C.; Johnson, J. E., Jr.

1980-01-01

The experimental studies on the mitochondria of insect and mammalian cells are examined with a view to an analysis of intrinsic mitochondrial senescence, and its relation to the age-related changes in other cell organelles. The fine structural and biochemical data support the concept that the mitochondria of fixed postmitotic cells may be the site of intrinsic aging because of the attack by free radicals and lipid peroxides originating in the organelles as a by-product of oxygen reduction during respiration. Although the cells have numerous mechanisms for counteracting lipid peroxidation injury, there is a slippage in the antioxidant protection. Intrinsic mitochondrial aging could thus be considered as a specific manifestation of oxygen toxicity. It is proposed that free radical injury renders an increasing number of the mitochondria unable to divide, probably because of damage to the lipids of the inner membrane and to mitochondrial DNA.

Nrf2-ARE activator carnosic acid decreases mitochondrial dysfunction, oxidative damage and neuronal cytoskeletal degradation following traumatic brain injury in mice.

PubMed

Miller, Darren M; Singh, Indrapal N; Wang, Juan A; Hall, Edward D

2015-02-01

The importance of free radical-induced oxidative damage after traumatic brain injury (TBI) has been well documented. Despite multiple clinical trials with radical-scavenging antioxidants that are neuroprotective in TBI models, none is approved for acute TBI patients. As an alternative antioxidant target, Nrf2 is a transcription factor that activates expression of antioxidant and cytoprotective genes by binding to antioxidant response elements (AREs) within DNA. Previous research has shown that neuronal mitochondria are susceptible to oxidative damage post-TBI, and thus the current study investigates whether Nrf2-ARE activation protects mitochondrial function when activated post-TBI. It was hypothesized that administration of carnosic acid (CA) would reduce oxidative damage biomarkers in the brain tissue and also preserve cortical mitochondrial respiratory function post-TBI. A mouse controlled cortical impact (CCI) model was employed with a 1.0mm cortical deformation injury. Administration of CA at 15 min post-TBI reduced cortical lipid peroxidation, protein nitration, and cytoskeletal breakdown markers in a dose-dependent manner at 48 h post-injury. Moreover, CA preserved mitochondrial respiratory function compared to vehicle animals. This was accompanied by decreased oxidative damage to mitochondrial proteins, suggesting the mechanistic connection of the two effects. Lastly, delaying the initial administration of CA up to 8h post-TBI was still capable of reducing cytoskeletal breakdown, thereby demonstrating a clinically relevant therapeutic window for this approach. This study demonstrates that pharmacological Nrf2-ARE induction is capable of neuroprotective efficacy when administered after TBI. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of taurine on ischemia-reperfusion injury.

PubMed

Schaffer, Stephen W; Jong, Chian Ju; Ito, Takashi; Azuma, Junichi

2014-01-01

Taurine is an abundant β-amino acid that regulates several events that dramatically influence the development of ischemia-reperfusion injury. One of these events is the extrusion of taurine and Na+ from the cell via the taurine/Na+ symport. The loss of Na+ during the ischemia-reperfusion insult limits the amount of available Na+ for Na+/Ca2+ exchange, an important process in the development of Ca2+ overload and the activation of the mitochondrial permeability transition, a key process in ischemia-reperfusion mediated cell death. Taurine also prevents excessive generation of reactive oxygen species by the respiratory chain, an event that also limits the activation of the MPT. Because taurine is an osmoregulator, changes in taurine concentration trigger "osmotic preconditioning," a process that activates an Akt-dependent cytoprotective signaling pathway that inhibits MPT pore formation. These effects of taurine have clinical implications, as experimental evidence reveals potential promise of taurine therapy in preventing cardiac damage during bypass surgery, heart transplantation and myocardial infarction. Moreover, severe loss of taurine from the heart during an ischemia-reperfusion insult may increase the risk of ventricular remodeling and development of heart failure.

Mechanism of Siglec-8-induced human eosinophil apoptosis: role of caspases and mitochondrial injury.

PubMed

Nutku, Esra; Hudson, Sherry A; Bochner, Bruce S

2005-10-28

Sialic acid binding immunoglobulin like lectin (Siglec)-8 crosslinking with specific antibodies causes human eosinophil apoptosis. Mechanisms by which Siglec-8 crosslinking induces apoptosis are not known. Peripheral blood eosinophils were examined for caspase, mitochondria and reactive oxygen species (ROS) involvement after incubating the cells with anti-Siglec-8 crosslinking Abs or control Abs, in the presence or absence of selective inhibitors. Siglec-8 crosslinking induced rapid cleavage of caspase-3, caspase-8, and caspase-9 in eosinophils. Selective caspase-8 and/or caspase-9 inhibitors inhibited this apoptosis. Siglec-8 crosslinking on eosinophils increased dissipation of mitochondrial membrane potential upstream of caspase activation. Rotenone and antimycin, inhibitors of mitochondrial respiratory chain components, completely inhibited apoptosis. Additional experiments with an inhibitor of ROS, diphenyleneiodonium, demonstrated that ROS was also essential for Siglec-8-mediated apoptosis and preceded Siglec-8-mediated mitochondrial dissipation. These experiments show that Siglec-8-induced apoptosis occurs through the sequential production of ROS, followed by induction of mitochondrial injury and caspase cleavage.

Inflammation, Iron, Energy Failure, and Oxidative Stress in the Pathogenesis of Multiple Sclerosis

PubMed Central

Haider, Lukas

2015-01-01

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system. Different trigger pathologies have been suggested by the primary cytodegenerative “inside-out” and primary inflammation-driven “outside-in” hypotheses. Recent data indicate that mitochondrial injury and subsequent energy failure are key factors in the induction of demyelination and neurodegeneration. The brain weighs only a few percent of the body mass but accounts for approximately 20% of the total basal oxygen consumption of mitochondria. Oxidative stress induces mitochondrial injury in patients with multiple sclerosis and energy failure in the central nervous system of susceptible individuals. The interconnected mechanisms responsible for free radical production in patients with multiple sclerosis are as follows: (i) inflammation-induced production of free radicals by activated immune cells, (ii) liberation of iron from the myelin sheets during demyelination, and (iii) mitochondrial injury and thus energy failure-related free radical production. In the present review, the different sources of oxidative stress and their relationships to patients with multiple sclerosis considering tissue injury mechanisms and clinical aspects have been discussed. PMID:26106458

Inhibition of Drp1 attenuates mitochondrial damage and myocardial injury in Coxsackievirus B3 induced myocarditis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Lin; Zhang, Ming; Yan, Rui

Viral myocarditis (VMC) is closely related to apoptosis, oxidative stress, innate immunity, and energy metabolism, which are all linked to mitochondrial dysfunction. A close nexus between mitochondrial dynamics and cardiovascular disease with mitochondrial dysfunction has been deeply researched, but there is still no relevant report in viral myocarditis. In this study, we aimed to explore the role of Dynamin-related protein 1 (Drp1)-linked mitochondrial fission in VMC. Mice were inoculated with the Coxsackievirus B3 (CVB3) and treated with mdivi1 (a Drp1 inhibitor). Protein expression of Drp1 was increased in mitochondria while decreased in cytoplasm and accompanied by excessive mitochondrial fission inmore » VMC mice. In addition, midivi1 treatment attenuate inflammatory cells infiltration in myocardium of the mice, serum Cardiac troponin I (CTnI) and Creatine kinase-MB (CK-MB) level. Mdivi1 also could improved the survival rate of mice and mitochondrial dysfunction reflected as the up-regulated mitochondrial marker enzymatic activities of succinate dehydrogenase (SDH), cytochrome c oxidase (COX) and mitochondrial membrane potential (MMP). At the same time, mdivi1 rescued the body weight loss, myocardial injury and apoptosis of cardiomyocyte. Furthermore, decease in LVEDs and increase in EF and FS were detected by echocardiogram, which indicated the improved myocardial function. Thus, Drp1-linked excessive mitochondrial fission contributed to VMC and midivi1 may be a potential therapeutic approach. - Highlights: • The expression of Drp1 is significantly increased in mitochondria while decreased in cytoplasm in VMC mice. • Drp1-linked excessive mitochondrial fission is involved in VMC. • Midivi1 treatment mitigate the mitochondrial damage, inflammation, apoptosis in VMC mice. • The disturbance of mitochondrial dynamics may be a new therapeutic target for VMC.« less

Involvement of the mitochondrial permeability transition pore in chronic ethanol-mediated liver injury in mice

PubMed Central

King, Adrienne L.; Swain, Telisha M.; Mao, Zhengkuan; Udoh, Uduak S.; Oliva, Claudia R.; Betancourt, Angela M.; Griguer, Corrine E.; Crowe, David R.; Lesort, Mathieu

2013-01-01

Chronic ethanol consumption increases sensitivity of the mitochondrial permeability transition (MPT) pore induction in liver. Ca2+ promotes MPT pore opening, and genetic ablation of cyclophilin D (CypD) increases the Ca2+ threshold for the MPT. We used wild-type (WT) and CypD-null (CypD−/−) mice fed a control or an ethanol-containing diet to investigate the role of the MPT in ethanol-mediated liver injury. Ca2+-mediated induction of the MPT and mitochondrial respiration were measured in isolated liver mitochondria. Steatosis was present in WT and CypD−/− mice fed ethanol and accompanied by increased terminal deoxynucleotidyl transferase dUTP-mediated nick-end label-positive nuclei. Autophagy was increased in ethanol-fed WT mice compared with ethanol-fed CypD−/− mice, as reflected by an increase in the ratio of microtubule protein 1 light chain 3B II to microtubule protein 1 light chain 3B I. Higher levels of p62 were measured in CypD−/− than WT mice. Ethanol decreased mitochondrial respiratory control ratios and select complex activities in WT and CypD−/− mice. Ethanol also increased CypD protein in liver of WT mice. Mitochondria from control- and ethanol-fed WT mice were more sensitive to Ca2+-mediated MPT pore induction than mitochondria from their CypD−/− counterparts. Mitochondria from ethanol-fed CypD−/− mice were also more sensitive to Ca2+-induced swelling than mitochondria from control-fed CypD−/− mice but were less sensitive than mitochondria from ethanol-fed WT mice. In summary, CypD deficiency was associated with impaired autophagy and did not prevent ethanol-mediated steatosis. Furthermore, increased MPT sensitivity was observed in mitochondria from ethanol-fed WT and CypD−/− mice. We conclude that chronic ethanol consumption likely lowers the threshold for CypD-regulated and -independent characteristics of the ethanol-mediated MPT pore in liver mitochondria. PMID:24356880

Mitochondrial DNA Unwinding Enzyme Required for Liver Regeneration | Center for Cancer Research

Cancer.gov

The liver has an exceptional capacity to proliferate. This ability allows the liver to regenerate its mass after partial surgical removal or injury and is the key to successful partial liver transplants. Liver cells, called hepatocytes, are packed with mitochondria, and regulating mitochondrial DNA (mtDNA) copy number is crucial to mitochondrial function, including energy

Ubiquinol treatment for TBI in male rats: Effects on mitochondrial integrity, injury severity, and neurometabolism.

PubMed

Pierce, Janet D; Gupte, Raeesa; Thimmesch, Amanda; Shen, Qiuhua; Hiebert, John B; Brooks, William M; Clancy, Richard L; Diaz, Francisco J; Harris, Janna L

2018-06-01

Following traumatic brain injury (TBI), there is significant secondary damage to cerebral tissue from increased free radicals and impaired mitochondrial function. This imbalance between reactive oxygen species (ROS) production and the effectiveness of cellular antioxidant defenses is termed oxidative stress. Often there are insufficient antioxidants to scavenge ROS, leading to alterations in cerebral structure and function. Attenuating oxidative stress following a TBI by administering an antioxidant may decrease secondary brain injury, and currently many drugs and supplements are being investigated. We explored an over-the-counter supplement called ubiquinol (reduced form of coenzyme Q10), a potent antioxidant naturally produced in brain mitochondria. We administered intra-arterial ubiquinol to rats to determine if it would reduce mitochondrial damage, apoptosis, and severity of a contusive TBI. Adult male F344 rats were randomly assigned to one of three groups: (1) Saline-TBI, (2) ubiquinol 30 minutes before TBI (UB-PreTBI), or (3) ubiquinol 30 minutes after TBI (UB-PostTBI). We found when ubiquinol was administered before or after TBI, rats had an acute reduction in brain mitochondrial damage, apoptosis, and two serum biomarkers of TBI severity, glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1). However, in vivo neurometabolic assessment with proton magnetic resonance spectroscopy did not show attenuated injury-induced changes. These findings are the first to show that ubiquinol preserves mitochondria and reduces cellular injury severity after TBI, and support further study of ubiquinol as a promising adjunct therapy for TBI. © 2018 Wiley Periodicals, Inc.

Calcium and ER stress mediate hepatic apoptosis after burn injury

PubMed Central

Gauglitz, Gerd G.; Song, Juquan; Kulp, Gabriela A.; Finnerty, Celeste C.; Cox, Robert A.; Barral, José M.; Herndon, David N.; Boehning, Darren

2009-01-01

Abstract A hallmark of the disease state following severe burn injury is decreased liver function, which results in gross metabolic derangements that compromise patient survival. The underlying mechanisms leading to hepatocyte dysfunction after burn are essentially unknown. The aim of the present study was to determine the underlying mechanisms leading to hepatocyte dysfunction and apoptosis after burn. Rats were randomized to either control (no burn) or burn (60% total body surface area burn) and sacrificed at various time‐points. Liver was either perfused to isolate primary rat hepatocytes, which were used for in vitro calcium imaging, or liver was harvested and processed for immunohistology, transmission electron microscopy, mitochondrial isolation, mass spectroscopy or Western blotting to determine the hepatic response to burn injury in vivo. We found that thermal injury leads to severely depleted endoplasmic reticulum (ER) calcium stores and consequent elevated cytosolic calcium concentrations in primary hepatocytes in vitro. Burn‐induced ER calcium depletion caused depressed hepatocyte responsiveness to signalling molecules that regulate hepatic homeostasis, such as vasopressin and the purinergic agonist ATP. In vivo, thermal injury resulted in activation of the ER stress response and major alterations in mitochondrial structure and function – effects which may be mediated by increased calcium release by inositol 1,4,5‐trisphosphate receptors. Our results reveal that thermal injury leads to dramatic hepatic disturbances in calcium homeostasis and resultant ER stress leading to mitochondrial abnormalities contributing to hepatic dysfunction and apoptosis after burn injury. PMID:20141609

Aniline Induces Oxidative Stress and Apoptosis of Primary Cultured Hepatocytes.

PubMed

Wang, Yue; Gao, Hong; Na, Xiao-Lin; Dong, Shu-Ying; Dong, Hong-Wei; Yu, Jia; Jia, Li; Wu, Yong-Hui

2016-11-30

The toxicity and carcinogenicity of aniline in humans and animals have been well documented. However, the molecular mechanism involved in aniline-induced liver toxicity and carcinogenesis remains unclear. In our research, primary cultured hepatocytes were exposed to aniline (0, 1.25, 2.50, 5.0 and 10.0 μg/mL) for 24 h in the presence or absence of N -acetyl-l-cysteine (NAC). Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT), mitochondrial membrane potential, DNA damage, cell viability, and apoptosis were detected. Levels of ROS and MDA were significantly increased and levels of GSH and CAT, activity of SOD, and mitochondrial membrane potential in hepatocytes were significantly decreased by aniline compared with the negative control group. The tail moment and DNA content of the tail in exposed groups were significantly higher than those in the negative control group. Cell viability was reduced and apoptotic death was induced by aniline in a concentration-dependent manner. The phenomena of ROS generation, oxidative damage, loss of mitochondrial membrane potential, DNA damage and apoptosis could be prevented if ROS inhibitor NAC was added. ROS generation is involved in the loss of mitochondrial membrane potential and DNA injury, which may play a role in aniline-induced apoptosis in hepatocytes. Our study provides insight into the mechanism of aniline-induced toxicity and apoptosis of hepatocytes.

Aniline Induces Oxidative Stress and Apoptosis of Primary Cultured Hepatocytes

PubMed Central

Wang, Yue; Gao, Hong; Na, Xiao-Lin; Dong, Shu-Ying; Dong, Hong-Wei; Yu, Jia; Jia, Li; Wu, Yong-Hui

2016-01-01

The toxicity and carcinogenicity of aniline in humans and animals have been well documented. However, the molecular mechanism involved in aniline-induced liver toxicity and carcinogenesis remains unclear. In our research, primary cultured hepatocytes were exposed to aniline (0, 1.25, 2.50, 5.0 and 10.0 μg/mL) for 24 h in the presence or absence of N-acetyl-l-cysteine (NAC). Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT), mitochondrial membrane potential, DNA damage, cell viability, and apoptosis were detected. Levels of ROS and MDA were significantly increased and levels of GSH and CAT, activity of SOD, and mitochondrial membrane potential in hepatocytes were significantly decreased by aniline compared with the negative control group. The tail moment and DNA content of the tail in exposed groups were significantly higher than those in the negative control group. Cell viability was reduced and apoptotic death was induced by aniline in a concentration-dependent manner. The phenomena of ROS generation, oxidative damage, loss of mitochondrial membrane potential, DNA damage and apoptosis could be prevented if ROS inhibitor NAC was added. ROS generation is involved in the loss of mitochondrial membrane potential and DNA injury, which may play a role in aniline-induced apoptosis in hepatocytes. Our study provides insight into the mechanism of aniline-induced toxicity and apoptosis of hepatocytes. PMID:27916916

Effects of a human recombinant alkaline phosphatase during impaired mitochondrial function in human renal proximal tubule epithelial cells.

PubMed

Peters, Esther; Schirris, Tom; van Asbeck, Alexander H; Gerretsen, Jelle; Eymael, Jennifer; Ashikov, Angel; Adjobo-Hermans, Merel J W; Russel, Frans; Pickkers, Peter; Masereeuw, Rosalinde

2017-02-05

Sepsis-associated acute kidney injury is a multifactorial syndrome in which inflammation and renal microcirculatory dysfunction play a profound role. Subsequently, renal tubule mitochondria reprioritize cellular functions to prevent further damage. Here, we investigated the putative protective effects of human recombinant alkaline phosphatase (recAP) during inhibition of mitochondrial respiration in conditionally immortalized human proximal tubule epithelial cells (ciPTEC). Full inhibition of mitochondrial oxygen consumption was obtained after 24h antimycin A treatment, which did not affect cell viability. While recAP did not affect the antimycin A-induced decreased oxygen consumption and increased hypoxia-inducible factor-1α or adrenomedullin gene expression levels, the antimycin A-induced increase of pro-inflammatory cytokines IL-6 and IL-8 was attenuated. Antimycin A tended to induce the release of detrimental purines ATP and ADP, which reached statistical significance when antimycin A was co-incubated with lipopolysaccharide, and were completely converted into cytoprotective adenosine by recAP. As the adenosine A 2A receptor was up-regulated after antimycin A exposure, an adenosine A 2A receptor knockout ciPTEC cell line was generated in which recAP still provided protection. Together, recAP did not affect oxygen consumption but attenuated the inflammatory response during impaired mitochondrial function, an effect suggested to be mediated by dephosphorylating ATP and ADP into adenosine. Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi Xinming; Cai Yan; Gong Likun

Aristolochic acid (AA), a natural nephrotoxin and carcinogen, can induce a progressive tubulointerstitial nephropathy. However, the mechanism by which AA causes renal injury remains largely unknown. Here we reported that the mitochondrial permeability transition (MPT) plays an important role in the renal injury induced by aristolochic acid I (AAI). We found that in the presence of Ca{sup 2+}, AAI caused mitochondrial swelling, leakage of Ca{sup 2+}, membrane depolarization, and release of cytochrome c in isolated kidney mitochondria. These alterations were suppressed by cyclosporin A (CsA), an agent known to inhibit MPT. Culture of HK-2 cell, a human renal tubular epithelialmore » cell line for 24 h with AAI caused a decrease in cellular ATP, mitochondrial membrane depolarization, cytochrome c release, and increase of caspase 3 activity. These toxic effects of AAI were attenuated by CsA and bongkrekic acid (BA), another specific MPT inhibitor. Furthermore, AAI greatly inhibited the activity of mitochondrial adenine nucleotide translocator (ANT) in isolated mitochondria. We suggested that ANT may mediate, at least in part, the AAI-induced MPT. Taken together, these results suggested that MPT plays a critical role in the pathogenesis of HK-2 cell injury induced by AAI and implied that MPT might contribute to human nephrotoxicity of aristolochic acid.« less

The axon-protective WLD(S) protein partially rescues mitochondrial respiration and glycolysis after axonal injury.

PubMed

Godzik, Katharina; Coleman, Michael P

2015-04-01

The axon-protective Wallerian degeneration slow (WLD(S)) protein can ameliorate the decline in axonal ATP levels after neurite transection. Here, we tested the hypothesis that this effect is associated with maintenance of mitochondrial respiration and/or glycolysis. We used isolated neurites of superior cervical ganglion (SCG) cultures in the Seahorse XF-24 Metabolic Flux Analyser to determine mitochondrial respiration and glycolysis under different conditions. We observed that both mitochondrial respiration and glycolysis declined significantly during the latent phase of Wallerian degeneration. WLD(S) partially reduced the decline both in glycolysis and in mitochondrial respiration. In addition, we found that depleting NAD levels in uncut cultures led to changes in mitochondrial respiration and glycolysis similar to those rescued by WLD(S) after cut, suggesting that the maintenance of NAD levels in Wld(S) neurites after axonal injury at least partially underlies the maintenance of ATP levels. However, by using another axon-protective mutation (Sarm1(-/-)), we could demonstrate that rescue of basal ECAR (and hence probably glycolysis) rather than basal OCR (mitochondrial respiration) may be part of the protective phenotype to delay Wallerian degeneration. These findings open new routes to study glycolysis and the connection between NAD and ATP levels in axon degeneration, which may help to eventually develop therapeutic strategies to treat neurodegenerative diseases.

The protective effect of baicalin against renal ischemia-reperfusion injury through inhibition of inflammation and apoptosis

PubMed Central

2014-01-01

Background Renal ischemia-reperfusion injury (IRI) increases the rates of acute kidney failure, delayed graft function, and early mortality after kidney transplantation. The pathophysiology involved includes oxidative stress, mitochondrial dysfunction, and immune-mediated injury. The anti-oxidation, anti-apoptosis, and anti-inflammation properties of baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis, have been verified. This study therefore assessed the effects of baicalin against renal IRI in rats. Methods Baicalin was intraperitoneally injected 30 min before renal ischemia. Serum and kidneys were harvested 24 h after reperfusion. Renal function and histological changes were assessed. Markers of oxidative stress, the Toll-like receptor (TLR)2 and TLR4 signaling pathway, mitochondrial stress, and cell apoptosis were also evaluated. Results Baicalin treatment decreased oxidative stress and histological injury, and improved kidney function, as well as inhibiting proinflammatory responses and tubular apoptosis. Baicalin pretreatment also reduced the expression of TLR2, TLR4, MyD88, p-NF-κB, and p-IκB proteins, as well as decreasing caspase-3 activity and increasing the Bcl-2/Bax ratio. Conclusions Baicalin may attenuate renal ischemia-reperfusion injury by inhibiting proinflammatory responses and mitochondria-mediated apoptosis. These effects are associated with the TLR2/4 signaling pathway and mitochondrial stress. PMID:24417870

The protective effect of baicalin against renal ischemia-reperfusion injury through inhibition of inflammation and apoptosis.

PubMed

Lin, Miao; Li, Long; Li, Liping; Pokhrel, Gaurab; Qi, Guisheng; Rong, Ruiming; Zhu, Tongyu

2014-01-13

Renal ischemia-reperfusion injury (IRI) increases the rates of acute kidney failure, delayed graft function, and early mortality after kidney transplantation. The pathophysiology involved includes oxidative stress, mitochondrial dysfunction, and immune-mediated injury. The anti-oxidation, anti-apoptosis, and anti-inflammation properties of baicalin, a flavonoid glycoside isolated from Scutellaria baicalensis, have been verified. This study therefore assessed the effects of baicalin against renal IRI in rats. Baicalin was intraperitoneally injected 30 min before renal ischemia. Serum and kidneys were harvested 24 h after reperfusion. Renal function and histological changes were assessed. Markers of oxidative stress, the Toll-like receptor (TLR)2 and TLR4 signaling pathway, mitochondrial stress, and cell apoptosis were also evaluated. Baicalin treatment decreased oxidative stress and histological injury, and improved kidney function, as well as inhibiting proinflammatory responses and tubular apoptosis. Baicalin pretreatment also reduced the expression of TLR2, TLR4, MyD88, p-NF-κB, and p-IκB proteins, as well as decreasing caspase-3 activity and increasing the Bcl-2/Bax ratio. Baicalin may attenuate renal ischemia-reperfusion injury by inhibiting proinflammatory responses and mitochondria-mediated apoptosis. These effects are associated with the TLR2/4 signaling pathway and mitochondrial stress.

Naringin ameliorates gentamicin-induced nephrotoxicity and associated mitochondrial dysfunction, apoptosis and inflammation in rats: possible mechanism of nephroprotection.

PubMed

Sahu, Bidya Dhar; Tatireddy, Srujana; Koneru, Meghana; Borkar, Roshan M; Kumar, Jerald Mahesh; Kuncha, Madhusudana; Srinivas, R; Shyam Sunder, R; Sistla, Ramakrishna

2014-05-15

Gentamicin-induced nephrotoxicity has been well documented, although its underlying mechanisms and preventive strategies remain to be investigated. The present study was designed to investigate the protective effect of naringin, a bioflavonoid, on gentamicin-induced nephrotoxicity and to elucidate the potential mechanism. Serum specific renal function parameters (blood urea nitrogen and creatinine) and histopathology of kidney tissues were evaluated to assess the gentamicin-induced nephrotoxicity. Renal oxidative stress (lipid peroxidation, protein carbonylation, enzymatic and non-enzymatic antioxidants), inflammatory (NF-kB [p65], TNF-α, IL-6 and MPO) and apoptotic (caspase 3, caspase 9, Bax, Bcl-2, p53 and DNA fragmentation) markers were also evaluated. Significant decrease in mitochondrial NADH dehydrogenase, succinate dehydrogenase, cytochrome c oxidase and mitochondrial redox activity indicated the gentamicin-induced mitochondrial dysfunction. Naringin (100mg/kg) treatment along with gentamicin restored the mitochondrial function and increased the renal endogenous antioxidant status. Gentamicin induced increased renal inflammatory cytokines (TNF-α and IL-6), nuclear protein expression of NF-κB (p65) and NF-κB-DNA binding activity and myeloperoxidase (MPO) activity were significantly decreased upon naringin treatment. In addition, naringin treatment significantly decreased the amount of cleaved caspase 3, Bax, and p53 protein expression and increased the Bcl-2 protein expression. Naringin treatment also ameliorated the extent of histologic injury and reduced inflammatory infiltration in renal tubules. U-HPLS-MS data revealed that naringin co-administration along with gentamicin did not alter the renal uptake and/or accumulation of gentamicin in kidney tissues. These findings suggest that naringin treatment attenuates renal dysfunction and structural damage through the reduction of oxidative stress, mitochondrial dysfunction, inflammation and apoptosis in the kidney. Copyright © 2014 Elsevier Inc. All rights reserved.

Smad3 deficiency protects mice from obesity-induced podocyte injury that precedes insulin resistance.

PubMed

Sun, Yu B Y; Qu, Xinli; Howard, Victor; Dai, Lie; Jiang, Xiaoyun; Ren, Yi; Fu, Ping; Puelles, Victor G; Nikolic-Paterson, David J; Caruana, Georgina; Bertram, John F; Sleeman, Mark W; Li, Jinhua

2015-08-01

Signaling by TGF-β/Smad3 plays a key role in renal fibrosis. As obesity is one of the major risk factors of chronic and end-stage renal disease, we studied the role of Smad3 signaling in the pathogenesis of obesity-related renal disease. After switching to a high fat diet, the onset of Smad3 C-terminal phosphorylation, increase in albuminuria, and the early stages of peripheral and renal insulin resistance occurred at 1 day, and 4 and 8 weeks, respectively, in C57BL/6 mice. The loss of synaptopodin, a functional marker of podocytes, and phosphorylation of the Smad3 linker region (T179 and S213) appeared after 4 weeks of the high fat diet. This suggests a temporal pattern of Smad3 signaling activation leading to kidney injury and subsequent insulin resistance in the development of obesity-related renal disease. In vivo, Smad3 knockout attenuated the high fat diet-induced proteinuria, renal fibrosis, overall podocyte injury, and mitochondrial dysfunction in podocytes. In vitro palmitate caused a rapid activation of Smad3 in 30 min, loss of synaptopodin in 2 days, and impaired insulin signaling in 3 days in isolated mouse podocytes. Blockade of either Smad3 phosphorylation by SIS3 (a Smad3 inhibitor) or T179 phosphorylation by flavopiridol (a CDK9 inhibitor) prevented the palmitate-induced loss of synaptopodin and mitochondrial function in podocytes. Thus, Smad3 signaling plays essential roles in obesity-related renal disease and may be a novel therapeutic target.

Enhanced Production of Adenosine Triphosphate by Pharmacological Activation of Adenosine Monophosphate-Activated Protein Kinase Ameliorates Acetaminophen-Induced Liver Injury

PubMed Central

Hwang, Jung Hwan; Kim, Yong-Hoon; Noh, Jung-Ran; Choi, Dong-Hee; Kim, Kyoung-Shim; Lee, Chul-Ho

2015-01-01

The hepatic cell death induced by acetaminophen (APAP) is closely related to cellular adenosine triphosphate (ATP) depletion, which is mainly caused by mitochondrial dysfunction. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of low energy status. AMPK regulates metabolic homeostasis by stimulating catabolic metabolism and suppressing anabolic pathways to increase cellular energy levels. We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo. Therefore, we hypothesized that the enhanced production of ATP via AMPK stimulation can lead to amelioration of APAP-induced liver failure. A769662, an allosteric activator of AMPK, produced a strong synergistic effect on AMPK Thr172 phosphorylation with APAP in primary hepatocytes and liver tissue. Interestingly, activation of AMPK by A769662 ameliorated the APAP-induced hepatotoxicity in C57BL/6N mice treated with APAP at a dose of 400 mg/kg intraperitoneally. However, mice treated with APAP alone developed massive centrilobular necrosis, and APAP increased their serum alanine aminotransferase and aspartate aminotransferase levels. Furthermore, A769662 administration prevented the loss of intracellular ATP without interfering with the APAP-mediated reduction of mitochondrial dysfunction. In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury. In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis. Furthermore, stimulation of AMPK may have potential therapeutic application for APAP overdose. PMID:26434492

Enhanced Production of Adenosine Triphosphate by Pharmacological Activation of Adenosine Monophosphate-Activated Protein Kinase Ameliorates Acetaminophen-Induced Liver Injury.

PubMed

Hwang, Jung Hwan; Kim, Yong-Hoon; Noh, Jung-Ran; Choi, Dong-Hee; Kim, Kyoung-Shim; Lee, Chul-Ho

2015-10-01

The hepatic cell death induced by acetaminophen (APAP) is closely related to cellular adenosine triphosphate (ATP) depletion, which is mainly caused by mitochondrial dysfunction. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of low energy status. AMPK regulates metabolic homeostasis by stimulating catabolic metabolism and suppressing anabolic pathways to increase cellular energy levels. We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo. Therefore, we hypothesized that the enhanced production of ATP via AMPK stimulation can lead to amelioration of APAP-induced liver failure. A769662, an allosteric activator of AMPK, produced a strong synergistic effect on AMPK Thr172 phosphorylation with APAP in primary hepatocytes and liver tissue. Interestingly, activation of AMPK by A769662 ameliorated the APAP-induced hepatotoxicity in C57BL/6N mice treated with APAP at a dose of 400 mg/kg intraperitoneally. However, mice treated with APAP alone developed massive centrilobular necrosis, and APAP increased their serum alanine aminotransferase and aspartate aminotransferase levels. Furthermore, A769662 administration prevented the loss of intracellular ATP without interfering with the APAP-mediated reduction of mitochondrial dysfunction. In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury. In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis. Furthermore, stimulation of AMPK may have potential therapeutic application for APAP overdose.

Anti-hypoxia effect of adenovirus-mediated expression of heat shock protein 70 (HSP70) on primary cultured neurons.

PubMed

Hu, Dan; Chen, Fuqiang; Guan, Chun; Yang, Fangfang; Qu, Yan

2013-09-01

Heat shock protein 70 (HSP70) has attracted great attention recently in hypoxia injury because of its close link to the recovery after hypoxic-ischemic damage in organs. However, the cellular mechanism underlying its protective roles remains unclear. In this study, we developed a recombinant adenovirus containing HSP70-GFP (vAd-HSP70-GFP) and studied the effect of virus-mediated expression of exogenous HSP70 gene on neurons in response to hypoxia-reoxygenation injury. Virus-mediated expression of HSP70 was detected as early as 24 hr and lasted until 10 days after infection. Neurons with 48 hr vAd-HSP70-GFP infection were exposed to 0, 0.5, 1, 2, 3, or 4 hr hypoxia followed by 1 hr reoxygenation. The mRNA and protein levels of HSP70 in neurons exposed to different lengths of hypoxia were compared by using RT-PCR and Western blotting (WB). The 1-hr hypoxia exposure showed the most significant increases in the HSP70 mRNA and protein level compared with other exposure durations. MTT assay showed that HSP70 overexpression significantly increased the neuronal viability, accompanied by decreased lactate dehydrogenase (LDH) activity in the culture medium after hypoxia-reoxygenation. Neurons with vAd-HSP70-GFP exhibited increased levels of mitochondrial cytochrome C (Cyt-C) and decreased levels of cytoplasmic Cyt-C compared with vAd-GFP-infected cells. These results suggest a neuroprotective role of exogenous HSP70 against hypoxia-reoxygenation injury, possibly via preventing initiation of mitochondrial apoptosis. Copyright © 2013 Wiley Periodicals, Inc.

Mitochondrial pharmacology: electron transport chain bypass as strategies to treat mitochondrial dysfunction.

PubMed

Atamna, Hani; Mackey, Jeanette; Dhahbi, Joseph M

2012-01-01

Mitochondrial dysfunction (primary or secondary) is detrimental to intermediary metabolism. Therapeutic strategies to treat/prevent mitochondrial dysfunction could be valuable for managing metabolic and age-related disorders. Here, we review strategies proposed to treat mitochondrial impairment. We then concentrate on redox-active agents, with mild-redox potential, who shuttle electrons among specific cytosolic or mitochondrial redox-centers. We propose that specific redox agents with mild redox potential (-0.1 V; 0.1 V) improve mitochondrial function because they can readily donate or accept electrons in biological systems, thus they enhance metabolic activity and prevent reactive oxygen species (ROS) production. These agents are likely to lack toxic effects because they lack the risk of inhibiting electron transfer in redox centers. This is different from redox agents with strong negative (-0.4 V; -0.2 V) or positive (0.2 V; 0.4 V) redox potentials who alter the redox status of redox-centers (i.e., become permanently reduced or oxidized). This view has been demonstrated by testing the effect of several redox active agents on cellular senescence. Methylene blue (MB, redox potential ≅10 mV) appears to readily cycle between the oxidized and reduced forms using specific mitochondrial and cytosolic redox centers. MB is most effective in delaying cell senescence and enhancing mitochondrial function in vivo and in vitro. Mild-redox agents can alter the biochemical activity of specific mitochondrial components, which then in response alters the expression of nuclear and mitochondrial genes. We present the concept of mitochondrial electron-carrier bypass as a potential result of mild-redox agents, a method to prevent ROS production, improve mitochondrial function, and delay cellular aging. Thus, mild-redox agents may prevent/delay mitochondria-driven disorders. Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.

Cyclosporine A normalizes mitochondrial coupling, reactive oxygen species production, and inflammation and partially restores skeletal muscle maximal oxidative capacity in experimental aortic cross-clamping.

PubMed

Pottecher, Julien; Guillot, Max; Belaidi, Elise; Charles, Anne-Laure; Lejay, Anne; Gharib, Abdallah; Diemunsch, Pierre; Geny, Bernard

2013-04-01

By binding to cyclophilin D, cyclosporine A (CsA) inhibits mitochondrial permeability transition pore (mPTP) opening and prevents mitochondrial dysfunction and ultimately cell death after ischemia-reperfusion (IR) injury in cardiac muscle. This study tested whether CsA would decrease skeletal muscle oxidative stress and mitochondrial dysfunctions after aortic cross-clamping related IR. Forty-five Wistar rats were investigated. The sham group (n = 8) had aortic exposure but no ischemia, the IR group (n = 10) had aortic cross-clamping for 3 hours followed by 2 hours of reperfusion, and the IR+CsA group (n = 9) had two intraperitoneal injections of 10 mg of CsA at 90 and 150 minutes of ischemia before reperfusion. Mitochondrial coupling (acceptor control ratio) and mitochondrial respiratory chain complexes' activities were measured. Reactive oxygen species (ROS) production, cyclophilin D expression, and muscle inflammation were determined using dihydroethidium staining, Western blot, and immunohistochemistry, respectively. An additional 18 sham rats were investigated to determine CsA blood levels and the effects of CsA on mitochondrial respiration and calcium retention capacity, a marker of mPTP opening, both in myocardium and gastrocnemius with and without CsA. Compared with sham, IR decreased mitochondrial coupling (1.38 ± 0.06 vs 1.98 ± 0.20; P = .0092), increased ROS production (3992 ± 706 arbitrary units [AU] vs 1812 ± 322 AU; P = .033), was associated with macrophage infiltration, and decreased maximal oxidative capacity (V(max): 4.08 ± 0.38 μmol O(2)/min/g vs 5.98 ± 0.56 μmol O(2)/min/g; P = .015). Despite IR, CsA treatment totally restored mitochondrial coupling (1.93 ± 0.12; P = .023 vs IR), normalized ROS (1569 ± 348 AU; P = .0098 vs IR), and decreased inflammation. The V(max) was slightly enhanced (5.02 ± 0.39 μmol O(2)/min/g; P = .33 vs IR; P = .35 vs sham). Compared with myocardium, gastrocnemius muscle was characterized by a decreased cyclophilin D content (-50%) associated with an earlier opening of mPTP (calcium retention capacity increased from 10.85 ± 1.35 μM/mg dry weight [DW] to 12.11 ± 2.77 μM/mg DW; P = .65; and from 11.07 ± 1.67 to 37.65 ± 11.41 μM/mg DW; P = .0098 in gastrocnemius and heart, respectively). Cyclosporine A normalized ROS production, decreased inflammation, and restored mitochondrial coupling during aortic cross-clamping. Incomplete Vmax protection might be due to low cyclophilin D expression in gastrocnemius, preventing CsA from blocking mPTP opening. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Effects of different acute high ambient temperatures on function of hepatic mitochondrial respiration, antioxidative enzymes, and oxidative injury in broiler chickens.

PubMed

Tan, G-Y; Yang, L; Fu, Y-Q; Feng, J-H; Zhang, M-H

2010-01-01

This study investigated the effects of different acute high ambient temperatures on dysfunction of hepatic mitochondrial respiration, the antioxidative enzyme system, and oxidative injury in broiler chickens. One hundred twenty-eight 6-wk-old broiler chickens were assigned randomly to 4 groups and subsequently exposed to 25 (control), 32, 35, and 38 degrees C (RH, 70 +/- 5%) for 3 h, respectively. The rectal temperatures, activity of antioxidative enzymes (superoxide dismutase, catalase, and glutathione peroxidase), content of malondialdehyde and protein carbonyl, and the activity of mitochondrial respiratory enzymes were determined. The results showed that exposure to high ambient temperature induced a significant elevation of rectal temperature, antioxidative enzyme activity, and formation of malondialdehyde and protein carbonyl, as well as dysfunction of the mitochondrial respiratory chain in comparison with control (P < 0.05). Almost all of the indicators changed in a temperature-dependent manner with the gradual increase of ambient temperature from 32 to 38 degrees C; differences in each parameter (except catalase) among the groups exposed to different high ambient temperatures were also statistically significant (P < 0.05). The results of the present study suggest that, in the broiler chicken model used here, acute exposure to high temperatures may depress the activity of the mitochondrial respiratory chain. This inactivation results subsequently in overproduction of reactive oxygen species, which ultimately results in oxidative injury. However, this hypothesis needs to be evaluated more rigorously in future studies. It has also been shown that, with the gradual increase in temperature, the oxidative injury induced by heat stress in broiler chickens becomes increasingly severe, and this stress response presents in a temperature-dependent manner in the temperature range of 32 to 38 degrees C.

In vivo high-resolution magic angle spinning magnetic and electron paramagnetic resonance spectroscopic analysis of mitochondria-targeted peptide in Drosophila melanogaster with trauma-induced thoracic injury.

PubMed

Constantinou, Caterina; Apidianakis, Yiorgos; Psychogios, Nikolaos; Righi, Valeria; Mindrinos, Michael N; Khan, Nadeem; Swartz, Harold M; Szeto, Hazel H; Tompkins, Ronald G; Rahme, Laurence G; Tzika, A Aria

2016-02-01

Trauma is the most common cause of mortality among individuals aged between 1 and 44 years and the third leading cause of mortality overall in the US. In this study, we examined the effects of trauma on the expression of genes in Drosophila melanogaster, a useful model for investigating genetics and physiology. After trauma was induced by a non-lethal needle puncture of the thorax, we observed the differential expression of genes encoding for mitochondrial uncoupling proteins, as well as those encoding for apoptosis-related and insulin signaling-related proteins, thus indicating muscle functional dysregulation. These results prompted us to examine the link between insulin signaling and mitochondrial dysfunction using in vivo nuclear magnetic resonance (NMR) with complementary electron paramagnetic resonance (EPR) spectroscopy. Trauma significantly increased insulin resistance biomarkers, and the NMR spectral profile of the aged flies with trauma-induced thoracic injury resembled that of insulin-resistant chico mutant flies. In addition, the mitochondrial redox status, as measured by EPR, was significantly altered following trauma, indicating mitochondrial uncoupling. A mitochondria-targeted compound, Szeto-Schiller (SS)-31 that promotes adenosine triphosphate (ATP) synthesis normalized the NMR spectral profile, as well as the mitochondrial redox status of the flies with trauma-induced thoracic injury, as assessed by EPR. Based on these findings, we propose a molecular mechanism responsible for trauma-related mortality and also propose that trauma sequelae in aging are linked to insulin signaling and mitochondrial dysfunction. Our findings further suggest that SS-31 attenuates trauma-associated pathological changes.

Mitochondrial Approaches to Protect Against Cardiac Ischemia and Reperfusion Injury

PubMed Central

Camara, Amadou K. S.; Bienengraeber, Martin; Stowe, David F.

2011-01-01

The mitochondrion is a vital component in cellular energy metabolism and intracellular signaling processes. Mitochondria are involved in a myriad of complex signaling cascades regulating cell death vs. survival. Importantly, mitochondrial dysfunction and the resulting oxidative and nitrosative stress are central in the pathogenesis of numerous human maladies including cardiovascular diseases, neurodegenerative diseases, diabetes, and retinal diseases, many of which are related. This review will examine the emerging understanding of the role of mitochondria in the etiology and progression of cardiovascular diseases and will explore potential therapeutic benefits of targeting the organelle in attenuating the disease process. Indeed, recent advances in mitochondrial biology have led to selective targeting of drugs designed to modulate or manipulate mitochondrial function, to the use of light therapy directed to the mitochondrial function, and to modification of the mitochondrial genome for potential therapeutic benefit. The approach to rationally treat mitochondrial dysfunction could lead to more effective interventions in cardiovascular diseases that to date have remained elusive. The central premise of this review is that if mitochondrial abnormalities contribute to the etiology of cardiovascular diseases (e.g., ischemic heart disease), alleviating the mitochondrial dysfunction will contribute to mitigating the severity or progression of the disease. To this end, this review will provide an overview of our current understanding of mitochondria function in cardiovascular diseases as well as the potential role for targeting mitochondria with potential drugs or other interventions that lead to protection against cell injury. PMID:21559063

Brain mitochondrial bioenergetics change with rapid and prolonged shifts in aggression in the honey bee, Apis mellifera.

PubMed

Rittschof, Clare C; Vekaria, Hemendra J; Palmer, Joseph H; Sullivan, Patrick G

2018-04-25

Neuronal function demands high-level energy production, and as such, a decline in mitochondrial respiration characterizes brain injury and disease. A growing number of studies, however, link brain mitochondrial function to behavioral modulation in non-diseased contexts. In the honey bee, we show for the first time that an acute social interaction, which invokes an aggressive response, may also cause a rapid decline in brain mitochondrial bioenergetics. The degree and speed of this decline has only been previously observed in the context of brain injury. Furthermore, in the honey bee, age-related increases in aggressive tendency are associated with increased baseline brain mitochondrial respiration, as well as increased plasticity in response to metabolic fuel type in vitro Similarly, diet restriction and ketone body feeding, which commonly enhance mammalian brain mitochondrial function in vivo , cause increased aggression. Thus, even in normal behavioral contexts, brain mitochondria show a surprising degree of variation in function over both rapid and prolonged time scales, with age predicting both baseline function and plasticity in function. These results suggest that mitochondrial function is integral to modulating aggression-related neuronal signaling. We hypothesize that variation in function reflects mitochondrial calcium buffering activity, and that shifts in mitochondrial function signal to the neuronal soma to regulate gene expression and neural energetic state. Modulating brain energetic state is emerging as a critical component of the regulation of behavior in non-diseased contexts. © 2018. Published by The Company of Biologists Ltd.

Synergistic interaction of fatty acids and oxysterols impairs mitochondrial function and limits liver adaptation during nafld progression.

PubMed

Bellanti, Francesco; Villani, Rosanna; Tamborra, Rosanna; Blonda, Maria; Iannelli, Giuseppina; di Bello, Giorgia; Facciorusso, Antonio; Poli, Giuseppe; Iuliano, Luigi; Avolio, Carlo; Vendemiale, Gianluigi; Serviddio, Gaetano

2018-05-01

The complete mechanism accounting for the progression from simple steatosis to steatohepatitis in nonalcoholic fatty liver disease (NAFLD) has not been elucidated. Lipotoxicity refers to cellular injury caused by hepatic free fatty acids (FFAs) and cholesterol accumulation. Excess cholesterol autoxidizes to oxysterols during oxidative stress conditions. We hypothesize that interaction of FAs and cholesterol derivatives may primarily impair mitochondrial function and affect biogenesis adaptation during NAFLD progression. We demonstrated that the accumulation of specific non-enzymatic oxysterols in the liver of animals fed high-fat+high-cholesterol diet induces mitochondrial damage and depletion of proteins of the respiratory chain complexes. When tested in vitro, 5α-cholestane-3β,5,6β-triol (triol) combined to FFAs was able to reduce respiration in isolated liver mitochondria, induced apoptosis in primary hepatocytes, and down-regulated transcription factors involved in mitochondrial biogenesis. Finally, a lower protein content in the mitochondrial respiratory chain complexes was observed in human non-alcoholic steatohepatitis. In conclusion, hepatic accumulation of FFAs and non-enzymatic oxysterols synergistically facilitates development and progression of NAFLD by impairing mitochondrial function, energy balance and biogenesis adaptation to chronic injury. Copyright © 2017. Published by Elsevier B.V.

Over-expression of mitochondrial creatine kinase in the murine heart improves functional recovery and protects against injury following ischaemia-reperfusion.

PubMed

Whittington, Hannah J; Ostrowski, Philip J; McAndrew, Debra J; Cao, Fang; Shaw, Andrew; Eykyn, Thomas R; Lake, Hannah; Tyler, Jack; Schneider, Jurgen E; Neubauer, Stefan; Zervou, Sevasti; Lygate, Craig A

2018-03-02

Mitochondrial creatine kinase (MtCK) couples ATP production via oxidative phosphorylation to phosphocreatine in the cytosol, which acts as a mobile energy store available for regeneration of ATP at times of high demand. We hypothesised that elevating MtCK would be beneficial in ischaemia-reperfusion (I/R) injury. Mice were created overexpressing the sarcomeric MtCK gene with αMHC promoter at the Rosa26 locus (MtCK-OE) and compared with wild-type (WT) littermates. MtCK activity was 27% higher than WT, with no change in other CK isoenzymes or creatine levels. Electron microscopy confirmed normal mitochondrial cell density and mitochondrial localisation of transgenic protein. Respiration in isolated mitochondria was unaltered and metabolomic analysis by 1H-NMR suggests that cellular metabolism was not grossly affected by transgene expression. There were no significant differences in cardiac structure or function under baseline conditions by cine-MRI or LV haemodynamics. In Langendorff-perfused hearts subjected to 20min ischaemia and 30 min reperfusion, MtCK-OE exhibited less ischaemic contracture and improved functional recovery (Rate pressure product 58% above WT; P < 0.001). These hearts had reduced myocardial infarct size, which was confirmed in vivo: 55±4% in WT vs 29±4% in MtCK-OE; P < 0.0001). Isolated cardiomyocytes from MtCK-OE hearts exhibited delayed opening of the mitochondrial permeability transition pore (mPTP) compared to WT, which was confirmed by reduced mitochondrial swelling in response to calcium. There was no detectable change in the structural integrity of the mitochondrial membrane. Modest elevation of MtCK activity in the heart does not adversely affect cellular metabolism, mitochondrial or in vivo cardiac function, but modifies mPTP opening to protect against I/R injury and improve functional recovery. Our findings support MtCK as a prime therapeutic target in myocardial ischaemia.

Mitochondrial Dysfunction, Through Impaired Autophagy, Leads to Endoplasmic Reticulum Stress, Deregulated Lipid Metabolism, and Pancreatitis in Animal Models.

PubMed

Biczo, Gyorgy; Vegh, Eszter T; Shalbueva, Natalia; Mareninova, Olga A; Elperin, Jason; Lotshaw, Ethan; Gretler, Sophie; Lugea, Aurelia; Malla, Sudarshan R; Dawson, David; Ruchala, Piotr; Whitelegge, Julian; French, Samuel W; Wen, Li; Husain, Sohail Z; Gorelick, Fred S; Hegyi, Peter; Rakonczay, Zoltan; Gukovsky, Ilya; Gukovskaya, Anna S

2018-02-01

Little is known about the signaling pathways that initiate and promote acute pancreatitis (AP). The pathogenesis of AP has been associated with abnormal increases in cytosolic Ca 2+ , mitochondrial dysfunction, impaired autophagy, and endoplasmic reticulum (ER) stress. We analyzed the mechanisms of these dysfunctions and their relationships, and how these contribute to development of AP in mice and rats. Pancreatitis was induced in C57BL/6J mice (control) and mice deficient in peptidylprolyl isomerase D (cyclophilin D, encoded by Ppid) by administration of L-arginine (also in rats), caerulein, bile acid, or an AP-inducing diet. Parameters of pancreatitis, mitochondrial function, autophagy, ER stress, and lipid metabolism were measured in pancreatic tissue, acinar cells, and isolated mitochondria. Some mice with AP were given trehalose to enhance autophagic efficiency. Human pancreatitis tissues were analyzed by immunofluorescence. Mitochondrial dysfunction in pancreas of mice with AP was induced by either mitochondrial Ca 2+ overload or through a Ca 2+ overload-independent pathway that involved reduced activity of ATP synthase (80% inhibition in pancreatic mitochondria isolated from rats or mice given L-arginine). Both pathways were mediated by cyclophilin D and led to mitochondrial depolarization and fragmentation. Mitochondrial dysfunction caused pancreatic ER stress, impaired autophagy, and deregulation of lipid metabolism. These pathologic responses were abrogated in cyclophilin D-knockout mice. Administration of trehalose largely prevented trypsinogen activation, necrosis, and other parameters of pancreatic injury in mice with L-arginine AP. Tissues from patients with pancreatitis had markers of mitochondrial damage and impaired autophagy, compared with normal pancreas. In different animal models, we find a central role for mitochondrial dysfunction, and for impaired autophagy as its principal downstream effector, in development of AP. In particular, the pathway involving enhanced interaction of cyclophilin D with ATP synthase mediates L-arginine-induced pancreatitis, a model of severe AP the pathogenesis of which has remained unknown. Strategies to restore mitochondrial and/or autophagic function might be developed for treatment of AP. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

Inhibitory effects of myricitrin on oxidative stress-induced endothelial damage and early atherosclerosis in ApoE −/− mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Gui-bo; Qin, Meng; Ye, Jing-xue

Atherosclerosis (AS) is a state of heightened oxidative stress characterized by lipid and protein oxidation in vascular walls. Oxidative stress-induced vascular endothelial cell (VEC) injury is a major factor in the pathogenesis of AS. Myricitrin, a natural flavonoid isolated from the root bark of Myrica cerifera, was recently found to have a strong antioxidative effect. However, its use for treating cardiovascular diseases, especially AS is still unreported. Consequently, we evaluated the cytoprotective effect of myricitrin on AS by assessing oxidative stress-induced VEC damage. The in vivo study using an ApoE −/− mouse model of AS demonstrated that myricitrin treatment protectsmore » against VEC damage and inhibits early AS plaque formation. This effect is associated with the antioxidative effect of myricitrin, as observed in a hydrogen peroxide (H{sub 2}O{sub 2})-induced rat model of artery endothelial injury and primary cultured human VECs. Myricitrin treatment also prevents and attenuates H{sub 2}O{sub 2}-induced endothelial injury. Further investigation of the cytoprotective effects of myricitrin demonstrated that myricitrin exerts its function by scavenging for reactive oxygen species, as well as reducing lipid peroxidation, blocking NO release, and maintaining mitochondrial transmembrane potential. Myricitrin treatment also significantly decreased H{sub 2}O{sub 2}-induced apoptosis in VECs, which was associated with significant inhibition of p53 gene expression, activation of caspase-3 and the MAPK signaling pathway, and alteration of the patterns of pro-apoptotic and anti-apoptotic gene expression. The resulting significantly increased bcl-2/bax ratio indicates that myricitrin may prevent the apoptosis induced by oxidative stress injury. - Highlights: • Myricitrin prevents early atherosclerosis in ApoE−/− mice. • Myricitrin protects endothelial cell from H{sub 2}O{sub 2} induced injury in rat and HUVECs. • Myricitrin enhanced NO release and up regulates eNOS activity in HUVECs. • Myricitrin down regulates P53 expression and MAPKs phosphorylation in HUVECs.« less

Sevoflurane postconditioning improves myocardial mitochondrial respiratory function and reduces myocardial ischemia-reperfusion injury by up-regulating HIF-1

PubMed Central

Yang, Long; Xie, Peng; Wu, Jianjiang; Yu, Jin; Yu, Tian; Wang, Haiying; Wang, Jiang; Xia, Zhengyuan; Zheng, Hong

2016-01-01

Background: Sevoflurane postconditioning (SPostC) can exert myocardial protective effects similar to ischemic preconditioning. However, the exact myocardial protection mechanism by SPostC is unclear. Studies indicate that hypoxia-inducible factor-1 (HIF-1) maintains cellular respiration homeostasis by regulating mitochondrial respiratory chain enzyme activity under hypoxic conditions. This study investigated whether SPostC could regulate the expression of myocardial HIF-1α and to improve mitochondrial respiratory function, thereby relieving myocardial ischemia-reperfusion injury in rats. Methods: The myocardial ischemia-reperfusion rat model was established using the Langendorff isolated heart perfusion apparatus. Additionally, postconditioning was performed using sevoflurane alone or in combination with the HIF-1α inhibitor 2-methoxyestradiol (2ME2). The changes in hemodynamic parameters, HIF-1α protein expression levels, mitochondrial respiratory function and enzyme activity, mitochondrial reactive oxygen species (ROS) production rates, and mitochondrial ultrastructure were measured or observed. Results: Compared to the ischemia-reperfusion (I/R) group, HIF-1α expression in the SPostC group was significantly up-regulated. Additionally, cardiac function indicators, mitochondrial state 3 respiratory rate, respiratory control ratio (RCR), cytochrome C oxidase (CcO), NADH oxidase (NADHO), and succinate oxidase (SUCO) activities, mitochondrial ROS production rate, and mitochondrial ultrastructure were significantly better than those in the I/R group. However, these advantages were completely reversed by the HIF-1α specific inhibitor 2ME2 (P<0.05). Conclusion: The myocardial protective function of SPostC might be associated with the improvement of mitochondrial respiratory function after up-regulation of HIF-1α expression. PMID:27830025

Sevoflurane postconditioning improves myocardial mitochondrial respiratory function and reduces myocardial ischemia-reperfusion injury by up-regulating HIF-1.

PubMed

Yang, Long; Xie, Peng; Wu, Jianjiang; Yu, Jin; Yu, Tian; Wang, Haiying; Wang, Jiang; Xia, Zhengyuan; Zheng, Hong

2016-01-01

Sevoflurane postconditioning (SPostC) can exert myocardial protective effects similar to ischemic preconditioning. However, the exact myocardial protection mechanism by SPostC is unclear. Studies indicate that hypoxia-inducible factor-1 (HIF-1) maintains cellular respiration homeostasis by regulating mitochondrial respiratory chain enzyme activity under hypoxic conditions. This study investigated whether SPostC could regulate the expression of myocardial HIF-1α and to improve mitochondrial respiratory function, thereby relieving myocardial ischemia-reperfusion injury in rats. The myocardial ischemia-reperfusion rat model was established using the Langendorff isolated heart perfusion apparatus. Additionally, postconditioning was performed using sevoflurane alone or in combination with the HIF-1α inhibitor 2-methoxyestradiol (2ME2). The changes in hemodynamic parameters, HIF-1α protein expression levels, mitochondrial respiratory function and enzyme activity, mitochondrial reactive oxygen species (ROS) production rates, and mitochondrial ultrastructure were measured or observed. Compared to the ischemia-reperfusion (I/R) group, HIF-1α expression in the SPostC group was significantly up-regulated. Additionally, cardiac function indicators, mitochondrial state 3 respiratory rate, respiratory control ratio (RCR), cytochrome C oxidase (C c O), NADH oxidase (NADHO), and succinate oxidase (SUCO) activities, mitochondrial ROS production rate, and mitochondrial ultrastructure were significantly better than those in the I/R group. However, these advantages were completely reversed by the HIF-1α specific inhibitor 2ME2 ( P <0.05). The myocardial protective function of SPostC might be associated with the improvement of mitochondrial respiratory function after up-regulation of HIF-1α expression.

The role of oxidative stress in organophosphate and nerve agent toxicity

PubMed Central

Pearson, Jennifer N.; Patel, Manisha

2016-01-01

Organophosphate nerve agents exert their toxicity through inhibition of acetylcholinesterase. The excessive stimulation of cholinergic receptors rapidly causes neuronal damage, seizures, death, and long-term neurological impairment in those that survive. Owing to the lethality of organophosphorus agents and the growing risk they pose, medical interventions that prevent organophosphate toxicity and the delayed injury response are much needed. Studies have shown that oxidative stress occurs in models of subacute, acute, and chronic exposure to organophosphate agents. Key findings of these studies include alterations in mitochondrial function and increased free radical–mediated injury, such as lipid peroxidation. This review focuses on the role of reactive oxygen species in organophosphate neurotoxicity and its dependence on seizure activity. Understanding the sources, mechanisms, and pathological consequences of organophosphate-induced oxidative stress can lead to the development of rational therapies for treating toxic exposures. PMID:27371936

Ischemia-induced endothelial cell swelling and mitochondrial dysfunction are attenuated by cinnamtannin D1, green tea extract, and resveratrol in vitro.

PubMed

Panickar, Kiran S; Qin, Bolin; Anderson, Richard A

2015-10-01

Polyphenols possess antioxidant and anti-inflammatory properties. Oxidative stress (OS) and inflammation have been implicated in the pathogenesis of cytotoxic brain edema in cerebral ischemia. In addition, OS and pro-inflammatory cytokines also damage the endothelial cells and the neurovascular unit. Endothelial cell swelling may contribute to a leaky blood-brain barrier which may result in vasogenic edema in the continued presence of the existing cytotoxic edema. We investigated the protective effects of polyphenols on cytotoxic cell swelling in bEND3 endothelial cultures subjected to 5 hours oxygen-glucose deprivation (OGD). A polyphenol trimer from cinnamon (cinnamtannin D1), a polyphenol-rich extract from green tea, and resveratrol prevented the OGD-induced rise in mitochondrial free radicals, cell swelling, and the dissipation of the inner mitochondrial membrane potential. Monocyte chemoattractant protein (also called CCL2), a chemokine, but not tumor necrosis factor-α or interleukin-6, augmented the cell swelling. This effect of monochemoattractant protein 1-1 was attenuated by the polyphenols. Cyclosporin A, a blocker of the mitochondrial permeability transition pore, did not attenuate cell swelling but BAPTA-AM, an intracellular calcium chelator did, indicating a role of [Ca(2+)]i but not the mPT in cell swelling. These results indicate that the polyphenols reduce mitochondrial reactive oxygen species and subsequent cell swelling in endothelial cells following ischemic injury and thus may reduce brain edema and associated neural damage in ischemia. One possible mechanism by which the polyphenols may attenuate endothelial cell swelling is through the reduction in [Ca(2+)]i.

Glucose fluctuation increased hepatocyte apoptosis under lipotoxicity and the involvement of mitochondrial permeability transition opening.

PubMed

Yin, Xueyao; Zheng, Fenping; Pan, Qianqian; Zhang, Saifei; Yu, Dan; Xu, Zhiye; Li, Hong

2015-12-01

Oxidative stress is considered to be an important factor in producing lethal hepatocyte injury associated with nonalcoholic fatty liver disease (NAFLD). Glucose fluctuation, more pronounced in patients with diabetes, has been recognized as an even stronger oxidative stress inducer than the sustained hyperglycemia. Here, we investigated the role of glucose variability in the development of the NAFLD based on hepatocyte apoptosis and possible mechanisms. To achieve this goal we studied C57BL/6J mice that were maintained on a high fat diet (HFD) and injected with glucose (3 g/kg) twice daily to induce intermittent high glucose (IHG). We also studied hepatic L02 cells incubated with palmitic acid (PA) to induce steatosis. The following experimental groups were compared: normal glucose (NG), sustained high glucose (SHG) and IHG with or without PA. We found that, although hepatic enzyme levels and liver lipid deposition were comparable between HFD mice injected with glucose or saline, the glucose injected mice displayed marked hepatocyte apoptosis and inflammation, accompanied by increased lipid peroxide in liver. In vitro, in the presence of PA, IHG increased L02 cell apoptosis and oxidative stress and produced pronounced mitochondrial dysfunction relative to the NG and SHG groups. Furthermore, treatment with the mitochondrial permeability transition (MPT) inhibitor, cyclosporin A (1.5 μmol/l), prevented mitochondrial dysfunction, oxidative stress and hepatocyte apoptosis. Our data suggests that IHG under lipotoxicity might contribute to the development of NAFLD by increasing oxidative stress and hepatocyte apoptosis via MPT and its related mitochondrial dysfunction. © 2015 Society for Endocrinology.

Targeted Modification of Mitochondrial ROS Production Converts High Glucose-Induced Cytotoxicity to Cytoprotection: Effects on Anesthetic Preconditioning.

PubMed

Sedlic, Filip; Muravyeva, Maria Y; Sepac, Ana; Sedlic, Marija; Williams, Anna Marie; Yang, Meiying; Bai, Xiaowen; Bosnjak, Zeljko J

2017-01-01

Contradictory reports on the effects of diabetes and hyperglycemia on myocardial infarction range from cytotoxicity to cytoprotection. The study was designed to investigate acute effects of high glucose-driven changes in mitochondrial metabolism and osmolarity on adaptive mechanisms and resistance to oxidative stress of isolated rat cardiomyocytes. We examined the effects of high glucose on several parameters of mitochondrial bioenergetics, including changes in oxygen consumption, mitochondrial membrane potential, and NAD(P)H fluorometry. Effects of high glucose on the endogenous cytoprotective mechanisms elicited by anesthetic preconditioning (APC) and the mediators of cell injury were also tested. These experiments included real-time measurements of reactive oxygen species (ROS) production and mitochondrial permeability transition pore (mPTP) opening in single cells by laser scanning fluorescence confocal microscopy, and cell survival assay. High glucose rapidly enhanced mitochondrial energy metabolism, observed by increase in NAD(P)H fluorescence intensity, oxygen consumption, and mitochondrial membrane potential. This substantially elevated production of ROS, accelerated opening of the mPTP, and decreased survival of cells exposed to oxidative stress. Abrogation of high glucose-induced mitochondrial hyperpolarization with 2,4 dinitrophenol (DNP) significantly, but not completely, attenuated ROS production to a level similar to hyperosmotic mannitol control. DNP treatment reversed high glucose-induced cytotoxicity to cytoprotection. Hyperosmotic mannitol treatment also induced cytoprotection. High glucose abrogated APC-induced mitochondrial depolarization, delay in mPTP opening and cytoprotection. In conclusion, high glucose-induced mitochondrial hyperpolarization abolishes APC and augments cell injury. Attenuation of high glucose-induced ROS production by eliminating mitochondrial hyperpolarization protects cardiomyocytes. J. Cell. Physiol. 232: 216-224, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Naringin Attenuates Cerebral Ischemia-Reperfusion Injury Through Inhibiting Peroxynitrite-Mediated Mitophagy Activation.

PubMed

Feng, Jinghan; Chen, Xingmiao; Lu, Shengwen; Li, Wenting; Yang, Dan; Su, Weiwei; Wang, Xijun; Shen, Jiangang

2018-04-07

Excessive autophagy/mitophagy plays important roles during cerebral ischemia-reperfusion (I/R) injury. Peroxynitrite (ONOO - ), a representative reactive nitrogen species, mediates excessive mitophagy activation and exacerbates cerebral I/R injury. In the present study, we tested the hypothesis that naringin, a natural antioxidant, could inhibit ONOO - -mediated mitophagy activation and attenuate cerebral I/R injury. Firstly, we demonstrated that naringin possessed strong ONOO - scavenging capability and also inhibited the production of superoxide and nitric oxide in SH-SY5Y cells exposed to 10 h oxygen-glucose-deprivation plus 14 h of reoxygenation or ONOO - donor 3-morpholinosydnonimine conditions. Naringin also inhibited the expression of NADPH oxidase subunits and iNOS in rat brains subjected to 2 h ischemia plus 22 h reperfusion. Next, we found that naringin was able to cross the blood-brain barrier, and naringin decreased neurological deficit score, reduced infarct size, and attenuated apoptotic cell death in the ischemia-reperfused rat brains. Furthermore, naringin reduced 3-nitrotyrosine formation, decreased the ratio of LC3-II to LC3-I in mitochondrial fraction, and inhibited the translocation of Parkin to the mitochondria. Taken together, naringin could be a potential therapeutic agent to prevent the brain from I/R injury via attenuating ONOO - -mediated excessive mitophagy.

MitoQ administration prevents endotoxin-induced cardiac dysfunction

PubMed Central

Murphy, M. P.; Callahan, L. A.

2009-01-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6′-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg·kg−1·day−1), saline + MitoQ (500 μM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction. PMID:19657095

MitoQ administration prevents endotoxin-induced cardiac dysfunction.

PubMed

Supinski, G S; Murphy, M P; Callahan, L A

2009-10-01

Sepsis elicits severe alterations in cardiac function, impairing cardiac mitochondrial and pressure-generating capacity. Currently, there are no therapies to prevent sepsis-induced cardiac dysfunction. We tested the hypothesis that administration of a mitochondrially targeted antioxidant, 10-(6'-ubiquinonyl)-decyltriphenylphosphonium (MitoQ), would prevent endotoxin-induced reductions in cardiac mitochondrial and contractile function. Studies were performed on adult rodents (n = 52) given either saline, endotoxin (8 mg x kg(-1) x day(-1)), saline + MitoQ (500 microM), or both endotoxin and MitoQ. At 48 h animals were killed and hearts were removed for determination of either cardiac mitochondrial function (using polarography) or cardiac pressure generation (using the Langendorf technique). We found that endotoxin induced reductions in mitochondrial state 3 respiration rates, the respiratory control ratio, and ATP generation. Moreover, MitoQ administration prevented each of these endotoxin-induced abnormalities, P < 0.001. We also found that endotoxin produced reductions in cardiac pressure-generating capacity, reducing the systolic pressure-diastolic relationship. MitoQ also prevented endotoxin-induced reductions in cardiac pressure generation, P < 0.01. One potential link between mitochondrial and contractile dysfunction is caspase activation; we found that endotoxin increased cardiac levels of active caspases 9 and 3 (P < 0.001), while MitoQ prevented this increase (P < 0.01). These data demonstrate that MitoQ is a potent inhibitor of endotoxin-induced mitochondrial and cardiac abnormalities. We speculate that this agent may prove a novel therapy for sepsis-induced cardiac dysfunction.

Protection against renal ischemia-reperfusion injury in vivo by the mitochondria targeted antioxidant MitoQ.

PubMed

Dare, Anna J; Bolton, Eleanor A; Pettigrew, Gavin J; Bradley, J Andrew; Saeb-Parsy, Kourosh; Murphy, Michael P

2015-08-01

Ischemia-reperfusion (IR) injury to the kidney occurs in a range of clinically important scenarios including hypotension, sepsis and in surgical procedures such as cardiac bypass surgery and kidney transplantation, leading to acute kidney injury (AKI). Mitochondrial oxidative damage is a significant contributor to the early phases of IR injury and may initiate a damaging inflammatory response. Here we assessed whether the mitochondria targeted antioxidant MitoQ could decrease oxidative damage during IR injury and thereby protect kidney function. To do this we exposed kidneys in mice to in vivo ischemia by bilaterally occluding the renal vessels followed by reperfusion for up to 24h. This caused renal dysfunction, measured by decreased creatinine clearance, and increased markers of oxidative damage. Administering MitoQ to the mice intravenously 15 min prior to ischemia protected the kidney from damage and dysfunction. These data indicate that mitochondrial oxidative damage contributes to kidney IR injury and that mitochondria targeted antioxidants such as MitoQ are potential therapies for renal dysfunction due to IR injury. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Protection against renal ischemia–reperfusion injury in vivo by the mitochondria targeted antioxidant MitoQ

PubMed Central

Dare, Anna J.; Bolton, Eleanor A.; Pettigrew, Gavin J.; Bradley, J. Andrew; Saeb-Parsy, Kourosh; Murphy, Michael P.

2015-01-01

Ischemia–reperfusion (IR) injury to the kidney occurs in a range of clinically important scenarios including hypotension, sepsis and in surgical procedures such as cardiac bypass surgery and kidney transplantation, leading to acute kidney injury (AKI). Mitochondrial oxidative damage is a significant contributor to the early phases of IR injury and may initiate a damaging inflammatory response. Here we assessed whether the mitochondria targeted antioxidant MitoQ could decrease oxidative damage during IR injury and thereby protect kidney function. To do this we exposed kidneys in mice to in vivo ischemia by bilaterally occluding the renal vessels followed by reperfusion for up to 24 h. This caused renal dysfunction, measured by decreased creatinine clearance, and increased markers of oxidative damage. Administering MitoQ to the mice intravenously 15 min prior to ischemia protected the kidney from damage and dysfunction. These data indicate that mitochondrial oxidative damage contributes to kidney IR injury and that mitochondria targeted antioxidants such as MitoQ are potential therapies for renal dysfunction due to IR injury. PMID:25965144

Time-controlled fasting prevents aging-like mitochondrial changes induced by persistent dietary fat overload in skeletal muscle

PubMed Central

Lettieri-Barbato, Daniele; Cannata, Stefano Maria; Casagrande, Viviana; Ciriolo, Maria Rosa

2018-01-01

A large body of evidence suggests that persistent dietary fat overload causes mitochondrial dysfunction and systemic metabolic gridlock. Mitochondrial and lipid metabolism in skeletal muscle (SkM) are severely affected upon persistent high fat diet (HFD) leading to premature tissue aging. Here, we designed weekly cycles of fasting (called as time-controlled fasting, TCF) and showed that they were effective in limiting mitochondrial damage and metabolic disturbances induced by HFD. Specifically, TCF was able to prevent the decline of adipose triglyceride lipase (Atgl), maintain efficient mitochondrial respiration in SkM as well as improve blood glucose and lipid profile. Atgl was found to be the mediator of such preventive effects as its downregulation or up-regulation in C2C12 myotubes triggers mitochondrial alteration or protects against the deleterious effects of high fat levels respectively. In conclusion, TCF could represent an effective strategy to limit mitochondrial impairment and metabolic inflexibility that are typically induced by modern western diets or during aging. PMID:29742122

Time-controlled fasting prevents aging-like mitochondrial changes induced by persistent dietary fat overload in skeletal muscle.

PubMed

Lettieri-Barbato, Daniele; Cannata, Stefano Maria; Casagrande, Viviana; Ciriolo, Maria Rosa; Aquilano, Katia

2018-01-01

A large body of evidence suggests that persistent dietary fat overload causes mitochondrial dysfunction and systemic metabolic gridlock. Mitochondrial and lipid metabolism in skeletal muscle (SkM) are severely affected upon persistent high fat diet (HFD) leading to premature tissue aging. Here, we designed weekly cycles of fasting (called as time-controlled fasting, TCF) and showed that they were effective in limiting mitochondrial damage and metabolic disturbances induced by HFD. Specifically, TCF was able to prevent the decline of adipose triglyceride lipase (Atgl), maintain efficient mitochondrial respiration in SkM as well as improve blood glucose and lipid profile. Atgl was found to be the mediator of such preventive effects as its downregulation or up-regulation in C2C12 myotubes triggers mitochondrial alteration or protects against the deleterious effects of high fat levels respectively. In conclusion, TCF could represent an effective strategy to limit mitochondrial impairment and metabolic inflexibility that are typically induced by modern western diets or during aging.

Behavioral benefits of maternal swimming are counteracted by neonatal hypoxia-ischemia in the offspring.

PubMed

Marcelino, Thiago Beltram; de Lemos Rodrigues, Patricia Idalina; Klein, Caroline Peres; Santos, Bernardo Gindri Dos; Miguel, Patrícia Maidana; Netto, Carlos Alexandre; Silva, Lenir Orlandi Pereira; Matté, Cristiane

2016-10-01

Hypoxia-ischemia (HI) represents one of the most common causes of neonatal encephalopathy. The central nervous system injury comprises several mechanisms, including inflammatory, excitotoxicity, and redox homeostasis unbalance leading to cell death and cognitive impairment. Exercise during pregnancy is a potential therapeutic tool due to benefits offered to mother and fetus. Swimming during pregnancy elicits a strong metabolic programming in the offspring's brain, evidenced by increased antioxidant enzymes, mitochondrial biogenesis, and neurogenesis. This article aims to evaluate whether the benefits of maternal exercise are able to prevent behavioral brain injury caused by neonatal HI. Female adult Wistar rats swam before and during pregnancy (30min/day, 5 days/week, 4 weeks). At 7(th) day after birth, the offspring was submitted to HI protocol and, in adulthood (60(th) day), it performed the behavioral tests. It was observed an increase in motor activity in the open field test in HI-rats, which was not prevented by maternal exercise. The rats subjected to maternal swimming presented an improved long-term memory in the object recognition task, which was totally reversed by neonatal HI encephalopathy. BDNF brain levels were not altered; suggesting that HI or maternal exercise effects were BDNF-independent. In summary, our data suggest a beneficial long-term effect of maternal swimming, despite not being robust enough to protect from HI injury. Copyright © 2016 Elsevier B.V. All rights reserved.

Inhibition of Methylglyoxal-Induced AGEs/RAGE Expression Contributes to Dermal Protection by N-Acetyl-L-Cysteine.

PubMed

Yang, Chun-Tao; Meng, Fu-Hui; Chen, Li; Li, Xiang; Cen, Lai-Jian; Wen, Yu-Hua; Li, Cai-Chen; Zhang, Hui

2017-01-01

Accumulation of advanced glycation end products (AGEs) is a major cause of diabetes mellitus (DM) skin complications. Methylglyoxal (MGO), a reactive dicarbonyl compound, is a crucial intermediate of AGEs generation. N-acetyl-L-cysteine (NAC), an active ingredient of some medicines, can induce endogenous GSH and hydrogen sulfide generation, and set off a condensation reaction with MGO. However, there is rare evidence to show NAC can alleviate DM-induced skin injury through inhibition of AGEs generation or toxicity. The present study aimed to observe the effects of NAC on MGO-induced inflammatory injury and investigate the roles of AGEs and its receptor (RAGE) in NAC's dermal protection in human HaCaT keratinocytes. The cells were exposed to MGO to simulate a high MGO status in diabetic blood or tissues. The content of AGEs in serum or cell medium was measured with ELISA. The protective effects of NAC against MGO-induce injury were evaluated by administration before MGO one hour, in virtue of cell viability, mitochondrial membrane potential, inflammation reaction, nuclear factor (NF)-κB activation, matrix metalloproteinase (MMP)-9 expression, as well as cellular behavioral function. We found the AGEs levels of patients with DM were elevated comparing with healthy volunteers. The in vitro AGEs generation was also able to be enhanced by the exposure of HaCaT cells to MGO, which reduced dose-dependently cellular viability, damaged mitochondrial function, triggered secretion of interleukin (IL)-6 and IL-8, activated NF-κB and upregulated MMP-9 expression. Furthermore, the exposure caused cellular adhesion and migration dysfunction, as well as collagen type I inhibition. Importantly, before the exposure to MGO, the preconditioning with NAC significantly attenuated MGO-induced AGEs generation, improved cellular viability and mitochondrial function, partially reversed the overexpression of proinflammatory factors and MMP-9, as well as the activation of NF-κB. Lastly, NAC blocked MGO-induced RAGE upregulation, and inhibition of RAGE with its neutralizing antibody significantly alleviated MGO-induced NF-κB activation, MMP-9 upregulation and inflammatory injury in HaCaT cells. The present work indicates the administration of NAC can prevent MGO-induced dermal inflammatory injury through inhibition of AGEs/RAGE signal, which may provide a basal support for the treatment of diabetic skin complications with NAC-containing medicines in the future. © 2017 The Author(s)Published by S. Karger AG, Basel.

Role of PPARγ in the Differentiation and Function of Neurons

PubMed Central

Quintanilla, Rodrigo A.; Utreras, Elias; Cabezas-Opazo, Fabián A.

2014-01-01

Neuronal processes (neurites and axons) have an important role in brain cells communication and, generally, they are damaged in neurodegenerative diseases. Recent evidence has showed that the activation of PPARγ pathway promoted neuronal differentiation and axon polarity. In addition, activation of PPARγ using thiazolidinediones (TZDs) prevented neurodegeneration by reducing neuronal death, improving mitochondrial function, and decreasing neuroinflammation in neuropathic pain. In this review, we will discuss important evidence that supports a possible role of PPARγ in neuronal development, improvement of neuronal health, and pain signaling. Therefore, activation of PPARγ is a potential target with therapeutic applications against neurodegenerative disorders, brain injury, and pain regulation. PMID:25246934

Modeling the effect of blunt impact on mitochondrial function in cartilage: implications for development of osteoarthritis.

PubMed

Kapitanov, Georgi I; Ayati, Bruce P; Martin, James A

2017-01-01

Osteoarthritis (OA) is a disease characterized by degeneration of joint cartilage. It is associated with pain and disability and is the result of either age and activity related joint wear or an injury. Non-invasive treatment options are scarce and prevention and early intervention methods are practically non-existent. The modeling effort presented in this article is constructed based on an emerging biological hypothesis-post-impact oxidative stress leads to cartilage cell apoptosis and hence the degeneration observed with the disease. The objective is to quantitatively describe the loss of cell viability and function in cartilage after an injurious impact and identify the key parameters and variables that contribute to this phenomenon. We constructed a system of differential equations that tracks cell viability, mitochondrial function, and concentrations of reactive oxygen species (ROS), adenosine triphosphate (ATP), and glycosaminoglycans (GAG). The system was solved using MATLAB and the equations' parameters were fit to existing data using a particle swarm algorithm. The model fits well the available data for cell viability, ATP production, and GAG content. Local sensitivity analysis shows that the initial amount of ROS is the most important parameter. The model we constructed is a viable method for producing in silico studies and with a few modifications, and data calibration and validation, may be a powerful predictive tool in the search for a non-invasive treatment for post-traumatic osteoarthritis.

Inhibitory effect of melatonin on necroptosis via repressing the Ripk3-PGAM5-CypD-mPTP pathway attenuates cardiac microvascular ischemia reperfusion injury.

PubMed

Zhou, Hao; Li, Dandan; Zhu, Pingjun; Ma, Qiang; Sam, Toan; Wang, Jin; Hu, Shunying; Chen, Yundai; Zhang, Yingmei

2018-05-16

The molecular features of necroptosis in cardiac ischemia reperfusion (IR) injury have been extensively explored. However, there have been no studies investigating the physiological regulatory mechanisms of melatonin acting on necroptosis in cardiac IR injury. This study was designed to determine the role of necroptosis in microvascular IR injury, and investigate the contribution of melatonin in repressing necroptosis and preventing IR-mediated endothelial system collapse. Our results demonstrated that Ripk3 was primarily activated by IR injury and consequently aggravated endothelial necroptosis, microvessel barrier dysfunction, capillary hyperpermeability, the inflammation response, microcirculatory vasospasms and microvascular perfusion defects. However, administration of melatonin prevented Ripk3 activation and provided a pro-survival advantage for the endothelial system in the context of cardiac IR injury, similar to the results obtained via genetic ablation of Ripk3. Functional investigations clearly illustrated that activated Ripk3 upregulated PGAM5 expression, and the latter repressed CypD phosphorylation, which obligated endothelial cells to undergo necroptosis via augmenting mPTP (mitochondrial permeability transition pore) opening. Interestingly, melatonin supplementation suppressed mPTP opening and interrupted endothelial necroptosis via blocking the Ripk3-PGAM5-CypD signal pathways. Taken together, our studies identified the Ripk3-PGAM5-CypD-mPTP axis as a new pathway responsible for reperfusion-mediated microvascular damage via initiating endothelial necroptosis. In contrast, melatonin treatment inhibited the Ripk3-PGAM5-CypD-mPTP cascade and thus reduced cellular necroptosis, conferring a protective advantage to the endothelial system in IR stress. These findings establish a new paradigm in microvascular IR injury and update the concept for cell death management handled by melatonin under the burden of reperfusion attack. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Cardiac-Specific Knockout of ETA Receptor Mitigates Paraquat-Induced Cardiac Contractile Dysfunction.

PubMed

Wang, Jiaxing; Lu, Songhe; Zheng, Qijun; Hu, Nan; Yu, Wenjun; Li, Na; Liu, Min; Gao, Beilei; Zhang, Guoyong; Zhang, Yingmei; Wang, Haichang

2016-07-01

Paraquat (1,1'-dim ethyl-4-4'-bipyridinium dichloride), a highly toxic quaternary ammonium herbicide widely used in agriculture, exerts potent toxic prooxidant effects resulting in multi-organ failure including the lung and heart although the underlying mechanism remains elusive. Recent evidence suggests possible involvement of endothelin system in paraquat-induced acute lung injury. This study was designed to examine the role of endothelin receptor A (ETA) in paraquat-induced cardiac contractile and mitochondrial injury. Wild-type (WT) and cardiac-specific ETA receptor knockout mice were challenged to paraquat (45 mg/kg, i.p.) for 48 h prior to the assessment of echocardiographic, cardiomyocyte contractile and intracellular Ca(2+) properties, as well as apoptosis and mitochondrial damage. Levels of the mitochondrial proteins for biogenesis and oxidative phosphorylation including UCP2, HSP90 and PGC1α were evaluated. Our results revealed that paraquat elicited cardiac enlargement, mechanical anomalies including compromised echocardiographic parameters (elevated left ventricular end-systolic and end-diastolic diameters as well as reduced factional shortening), suppressed cardiomyocyte contractile function, intracellular Ca(2+) handling, overt apoptosis and mitochondrial damage. ETA receptor knockout itself failed to affect myocardial function, apoptosis, mitochondrial integrity and mitochondrial protein expression. However, ETA receptor knockout ablated or significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) defect, apoptosis and mitochondrial damage. Taken together, these findings revealed that endothelin system in particular the ETA receptor may be involved in paraquat-induced toxic myocardial contractile anomalies possibly related to apoptosis and mitochondrial damage.

Myricetin and quercetin attenuate ischemic injury in glial cultures by different mechanisms

USDA-ARS?s Scientific Manuscript database

We have demonstrated that polyphenols from cinnamon and green tea reduce cell swelling and mitochondrial dysfunction in C6 glial cultures following ischemic injury. We tested the protective effects of the flavonoid polyphenols, myricetin and quercetin, on key features of ischemic injury. C6 cultures...

[Hyperbaric oxygen therapy and inert gases in cerebral ischemia and traumatic brain injury].

PubMed

Chhor, V; Canini, F; De Rudnicki, S; Dahmani, S; Gressens, P; Constantin, P

2013-12-01

Cerebral ischemia is a common thread of acute cerebral lesions, whether vascular or traumatic origin. Hyperbaric oxygen (HBO) improves tissue oxygenation and may prevent impairment of reversible lesions. In experimental models of cerebral ischemia or traumatic brain injury, HBO has neuroprotective effects which are related to various mechanisms such as modulation of oxidative stress, neuro-inflammation or cerebral and mitochondrial metabolism. However, results of clinical trials failed to prove any neuroprotective effects for cerebral ischemia and remained to be confirmed for traumatic brain injury despite preliminary encouraging results. The addition of inert gases to HBO sessions, especially argon or xenon which show neuroprotective experimental effects, may provide an additional improvement of cerebral lesions. Further multicentric studies with a strict methodology and a better targeted definition are required before drawing definitive conclusions about the efficiency of combined therapy with HBO and inert gases in acute cerebral lesions. Copyright © 2013 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

Protective Effect of Bendavia (SS-31) Against Oxygen/Glucose-Deprivation Stress-Induced Mitochondrial Damage in Human Brain Microvascular Endothelial Cells.

PubMed

Imai, Takahiko; Mishiro, Keisuke; Takagi, Toshinori; Isono, Aoi; Nagasawa, Hideko; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

2017-01-01

Mitochondria play a key role in cell survival by perfoming functions such as adenosine tri-phosphate (ATP) synthesis, regulation of apoptotic cell death, calcium storage. Hypoxic conditions induce mitochondrial dysfunction, which leads to endothelial injury in cerebral ischemia. Functional disorders include the following: collapse of mitochondrial membrane potential, reduction of ATP synthesis, and generation of reactive oxygen species (ROS). Bendavia, a novel tetra-peptide, has been reported to restrict the uncoupling of the mitochondrial membrane chain, protect the synthesis of ATP, and inhibit ROS generation. In the present study, we investigated whether bendavia protects mitochondria under hypoxic and starved conditions by using human brain microvascular endothelial cells (HBMVECs). After pre-treatment with bendavia, we exposed HBMVECs to oxygen glucose deprivation (OGD) for 6 h. We then assessed cell viability, the level of caspase-3/7 activity, ROS generation, mitochondrial membrane potential, ATP contents, and the number of mitochondria. Bendavia recovered cell viability and reduced the caspase-3/7 activity induced by OGDinduced damage. Bendavia also recovered mitochondrial functions. These results suggest that bendavia protects mitochondrial function against OGD-induced injury and inhibits apoptosis in HBMVECs. Consequently, our findings indicate that bendavia might become the new therapeutic drug of choice to target mitochondria in case of cerebral ischemia. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

CRISPR/Cas9 and mitochondrial gene replacement therapy: promising techniques and ethical considerations

PubMed Central

Fogleman, Sarah; Santana, Casey; Bishop, Casey; Miller, Alyssa; Capco, David G

2016-01-01

Thousands of mothers are at risk of transmitting mitochondrial diseases to their offspring each year, with the most severe form of these diseases being fatal [1]. With no cure, transmission prevention is the only current hope for decreasing the disease incidence. Current methods of prevention rely on low mutant maternal mitochondrial DNA levels, while those with levels close to or above threshold (>60%) are still at a very high risk of transmission [2]. Two novel approaches may offer hope for preventing and treating mitochondrial disease: mitochondrial replacement therapy, and CRISPR/Cas9. Mitochondrial replacement therapy has emerged as a promising tool that has the potential to prevent transmission in patients with higher mutant mitochondrial loads. This method is the subject of many ethical concerns due its use of a donor embryo to transplant the patient’s nuclear DNA; however, it has ultimately been approved for use in the United Kingdom and was recently declared ethically permissible by the FDA. The leading-edge CRISPR/Cas9 technology exploits the principles of bacterial immune function to target and remove specific sequences of mutated DNA. This may have potential in treating individuals with disease caused by mutant mitochondrial DNA. As the technology progresses, it is important that the ethical considerations herein emerge and become more established. The purpose of this review is to discuss current research surrounding the procedure and efficacy of the techniques, compare the ethical concerns of each approach, and look into the future of mitochondrial gene replacement therapy. PMID:27725916

Ginsenoside Rg3 attenuates sepsis-induced injury and mitochondrial dysfunction in liver via AMPK-mediated autophagy flux.

PubMed

Xing, Wei; Yang, Lei; Peng, Yue; Wang, Qianlu; Gao, Min; Yang, Mingshi; Xiao, Xianzhong

2017-08-31

Sepsis-led mitochondrial dysfunction has become a critical pathophysiological procedure in sepsis. Since ginsenosides have been applied in the treatment of mitochondrial dysfunction, ginsenoside Rg3 was employed to study its effects on the mitochondrial dysfunction induced by sepsis. The apoptosis rate, oxygen consumption rate (OCR), reactive oxygen species (ROS), antioxidant glutathione (GSH) pools, and mitochondrial transmembrane potential (MTP) were determined in LPS-induced sepsis hepatocytes treated with different concentrations of Rg3. Then, the protein expression levels of mitochondrial biogenesis related transcription factors, autophagy-related proteins, and AMP-activated protein kinase (AMPK) signal pathway related proteins were determined by Western blotting in both in vitro and in vivo sepsis models. Rg3 shows functions of promotion of OCR, attenuation of ROS, and maintenance of GSH pools, and its conjugating activity in the in vitro sepsis models. Rg3-treated cells were observed to have a higher MTP value compared with the LPS only induced cells. Moreover, Rg3 treatment can inhibit mitochondrial dysfunction via increasing the protein expression levels of mitochondrial biogenesis related transcription factors. Rg3 treatment has the function of inhibitor of apoptosis of human primary hepatocytes, and Rg3 can up-regulate the autophagy-related proteins and activate AMPK signal pathway in sepsis models. Meanwhile, the mitochondrial protective function exerted by Rg3 decreased after the autophagy inhibitors or AMPK inhibitor treatment in LPS-induced human primary hepatocytes. Rg3 can improve mitochondrial dysfunction by regulating autophagy in mitochondria via activating the AMPK signal pathway, thus protecting cell and organ injuries caused by sepsis. © 2017 The Author(s).

Protective effects of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone to PC12 cells against cytotoxicity induced by hydrogen peroxide.

PubMed

Su, Ming-Yuan; Huang, Hai-Ya; Li, Lin; Lu, Yan-Hua

2011-01-26

Oxidative stress has been considered as a major cause of cellular injuries in various clinical abnormalities. One of the possible ways to prevent reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical therapies to augment the endogenous antioxidant defense capacity. The present study found that 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), a chalcone isolated from the buds of Cleistocalyx operculatus, possessed cytoprotective activity in PC12 cells treated with H(2)O(2). The results showed that DMC could effectively increase cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) reduction], decrease the cell apoptotic percentage [annexin V/propidium iodide (AV/PI) assay], prevent the membrane from damage [lactate dehydrogenase (LDH) release], scavenge ROS formation, reduce caspase-3 activity, and attenuate the decrease of mitochondrial membrane potential (MMP) in PC12 cells treated with H(2)O(2). Meanwhile, DMC increased the catalytic activity of superoxide dismutase (SOD) and the cellular amount of glutathione (GSH), decreased the cellular amount of malondialdehyde (MDA), and decreased the production of lipid peroxidation in PC12 cells treated with H(2)O(2).

Lipotoxicity Causes Multisystem Organ Failure and Exacerbates Acute Pancreatitis in Obesity

PubMed Central

Navina, Sarah; Acharya, Chathur; DeLany, James P.; Orlichenko, Lidiya S.; Baty, Catherine J.; Shiva, Sruti S.; Durgampudi, Chandra; Karlsson, Jenny M.; Lee, Kenneth; Bae, Kyongtae T.; Furlan, Alessandro; Behari, Jaideep; Liu, Shiguang; McHale, Teresa; Nichols, Larry; Papachristou, Georgios Ioannis; Yadav, Dhiraj; Singh, Vijay P.

2012-01-01

Obesity increases the risk of adverse outcomes during acute critical illnesses such as burns, severe trauma, and acute pancreatitis. Although individuals with more body fat and higher serum cytokines and lipase are more likely to experience problems, the roles that these characteristics play are not clear. We used severe acute pancreatitis as a representative disease to investigate the effects of obesity on local organ function and systemic processes. In obese humans, we found that an increase in the volume of intrapancreatic adipocytes was associated with more extensive pancreatic necrosis during acute pancreatitis and that acute pancreatitis was associated with multisystem organ failure in obese individuals. In vitro studies of pancreatic acinar cells showed that unsaturated fatty acids were proinflammatory, releasing intracellular calcium, inhibiting mitochondrial complexes I and V, and causing necrosis. Saturated fatty acids had no such effects. Inhibition of lipolysis in obese (ob/ob) mice with induced pancreatitis prevented a rise in serum unsaturated fatty acids and prevented renal injury, lung injury, systemic inflammation, hypocalcemia, reduced pancreatic necrosis, and mortality. Thus, therapeutic approaches that target unsaturated fatty acid–mediated lipotoxicity may reduce adverse outcomes in obese patients with critical illnesses such as severe acute pancreatitis. PMID:22049070

Increase in Cardiac Ischemia-Reperfusion Injuries in Opa1+/- Mouse Model

PubMed Central

Fauconnier, Jérémy; Cellier, Laura; Tamareille, Sophie; Gharib, Abdallah; Chevrollier, Arnaud; Loufrani, Laurent; Grenier, Céline; Kamel, Rima; Sarzi, Emmanuelle; Lacampagne, Alain; Ovize, Michel; Henrion, Daniel; Reynier, Pascal; Lenaers, Guy; Mirebeau-Prunier, Delphine

2016-01-01

Background Recent data suggests the involvement of mitochondrial dynamics in cardiac ischemia/reperfusion (I/R) injuries. Whilst excessive mitochondrial fission has been described as detrimental, the role of fusion proteins in this context remains uncertain. Objectives To investigate whether Opa1 (protein involved in mitochondrial inner-membrane fusion) deficiency affects I/R injuries. Methods and Results We examined mice exhibiting Opa1delTTAG mutations (Opa1+/-), showing 70% Opa1 protein expression in the myocardium as compared to their wild-type (WT) littermates. Cardiac left-ventricular systolic function assessed by means of echocardiography was observed to be similar in 3-month-old WT and Opa1+/- mice. After subjection to I/R, infarct size was significantly greater in Opa1+/- than in WTs both in vivo (43.2±4.1% vs. 28.4±3.5%, respectively; p<0.01) and ex vivo (71.1±3.2% vs. 59.6±8.5%, respectively; p<0.05). No difference was observed in the expression of other main fission/fusion protein, oxidative phosphorylation, apoptotic markers, or mitochondrial permeability transition pore (mPTP) function. Analysis of calcium transients in isolated ventricular cardiomyocytes demonstrated a lower sarcoplasmic reticulum Ca2+ uptake, whereas cytosolic Ca2+ removal from the Na+/Ca2+ exchanger (NCX) was increased, whilst SERCA2a, phospholamban, and NCX protein expression levels were unaffected in Opa1+/- compared to WT mice. Simultaneous whole-cell patch-clamp recordings of mitochondrial Ca2+ movements and ventricular action potential (AP) showed impairment of dynamic mitochondrial Ca2+ uptake and a marked increase in the AP late repolarization phase in conjunction with greater occurrence of arrhythmia in Opa1+/- mice. Conclusion Opa1 deficiency was associated with increased sensitivity to I/R, imbalance in dynamic mitochondrial Ca2+ uptake, and subsequent increase in NCX activity. PMID:27723783

ALDH2 restores exhaustive exercise-induced mitochondrial dysfunction in skeletal muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Qiuping; Zheng, Jianheng; Qiu, Jun

Background: Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is highly expressed in heart and skeletal muscles, and is the major enzyme that metabolizes acetaldehyde and toxic aldehydes. The cardioprotective effects of ALDH2 during cardiac ischemia/reperfusion injury have been recognized. However, less is known about the function of ALDH2 in skeletal muscle. This study was designed to evaluate the effect of ALDH2 on exhaustive exercise-induced skeletal muscle injury. Methods: We created transgenic mice expressing ALDH2 in skeletal muscles. Male wild-type C57/BL6 (WT) and ALDH2 transgenic mice (ALDH2-Tg), 8-weeks old, were challenged with exhaustive exercise for 1 week to induce skeletal muscle injury. Animalsmore » were sacrificed 24 h post-exercise and muscle tissue was excised. Results: ALDH2-Tg mice displayed significantly increased treadmill exercise capacity compared to WT mice. Exhaustive exercise caused an increase in mRNA levels of the muscle atrophy markers, Atrogin-1 and MuRF1, and reduced mitochondrial biogenesis and fusion in WT skeletal muscles; these effects were attenuated in ALDH2-Tg mice. Exhaustive exercise also enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of Beclin1 and Bnip3; the effects of which were mitigated by ALDH2 overexpression. In addition, ALDH2-Tg reversed the increase of an oxidative stress biomarker (4-hydroxynonenal) and decreased levels of mitochondrial antioxidant proteins, including manganese superoxide dismutase and NAD(P)H:quinone oxidoreductase 1, in skeletal muscle induced by exhaustive exercise. Conclusion: ALDH2 may reverse skeletal muscle mitochondrial dysfunction due to exhaustive exercise by regulating mitochondria dynamic remodeling and enhancing the quality of mitochondria. - Highlights: • Skeletal muscle ALDH2 expression and activity declines during exhaustive exercise. • ALDH2 overexpression enhances physical performance and restores muscle atrophy. • ALDH2 overexpression attenuates exercise-induced mitochondrial oxidative stress.« less

Sonic hedgehog promotes neurite outgrowth of cortical neurons under oxidative stress: Involving of mitochondria and energy metabolism.

PubMed

He, Weiliang; Cui, Lili; Zhang, Cong; Zhang, Xiangjian; He, Junna; Xie, Yanzhao; Chen, Yanxia

2017-01-01

Oxidative stress has been demonstrated to be involved in the etiology of several neurobiological disorders. Sonic hedgehog (Shh), a secreted glycoprotein factor, has been implicated in promoting several aspects of brain remodeling process. Mitochondria may play an important role in controlling fundamental processes in neuroplasticity. However, little evidence is available about the effect and the potential mechanism of Shh on neurite outgrowth in primary cortical neurons under oxidative stress. Here, we revealed that Shh treatment significantly increased the viability of cortical neurons in a dose-dependent manner, which was damaged by hydrogen peroxide (H 2 O 2 ). Shh alleviated the apoptosis rate of H 2 O 2 -induced neurons. Shh also increased neuritogenesis injuried by H 2 O 2 in primary cortical neurons. Moreover, Shh reduced the generation of reactive oxygen species (ROS), increased the activities of SOD and and decreased the productions of MDA. In addition, Shh protected mitochondrial functions, elevated the cellular ATP levels and amelioratesd the impairment of mitochondrial complex II activities of cortical neurons induced by H 2 O 2 . In conclusion, all these results suggest that Shh acts as a prosurvival factor playing an essential role to neurite outgrowth of cortical neuron under H 2 O 2 -induced oxidative stress, possibly through counteracting ROS release and preventing mitochondrial dysfunction and ATP as well as mitochondrial complex II activities against oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

C-Phycocyanin protects against mitochondrial dysfunction and oxidative stress in parthenogenetic porcine embryos.

PubMed

Niu, Ying-Jie; Zhou, Wenjun; Guo, Jing; Nie, Zheng-Wen; Shin, Kyung-Tae; Kim, Nam-Hyung; Lv, Wen-Fa; Cui, Xiang-Shun

2017-12-05

C-Phycocyanin (CP) is a biliprotein enriched in blue-green algae that is known to possess antioxidant, anti-apoptosis, anti-inflammatory, and radical-scavenging properties in somatic cells. However, the protective effect of CP on porcine embryo developmental competence in vitro remains unclear. In the present study, we investigated the effect of CP on the development of early porcine embryos as well as its underlying mechanisms. Different concentrations of CP (2, 5, 8, 10 μg/mL) were added to porcine zygote medium 5 during in vitro culture. The results showed that 5 μg/mL CP significantly increased blastocyst formation and hatching rate. Blastocyst formation and quality were significantly increased in the 50 μM H 2 O 2 treatment group following 5 μg/mL CP addition. CP prevented the H 2 O 2 -induced compromise of mitochondrial membrane potential, release of cytochrome c from the mitochondria, and reactive oxygen species generation. Furthermore, apoptosis, DNA damage level, and autophagy in the blastocysts were attenuated by supplementation of CP in the H 2 O 2 -induced oxidative injury group compared to in controls. These results suggest that CP has beneficial effects on the development of porcine parthenotes by attenuating mitochondrial dysfunction and oxidative stress.

Cyclosporine A at reperfusion fails to reduce infarct size in the in vivo rat heart.

PubMed

De Paulis, Damien; Chiari, Pascal; Teixeira, Geoffrey; Couture-Lepetit, Elisabeth; Abrial, Maryline; Argaud, Laurent; Gharib, Abdallah; Ovize, Michel

2013-09-01

We examined the effects on infarct size and mitochondrial function of ischemic (Isch), cyclosporine A (CsA) and isoflurane (Iso) preconditioning and postconditioning in the in vivo rat model. Anesthetized open-chest rats underwent 30 min of ischemia followed by either 120 min (protocol 1: infarct size assessment) or 15 min of reperfusion (protocol 2: assessment of mitochondrial function). All treatments administered before the 30-min ischemia (Pre-Isch, Pre-CsA, Pre-Iso) significantly reduced infarct as compared to control. In contrast, only Post-Iso significantly reduced infarct size, while Post-Isch and Post-CsA had no significant protective effect. As for the postconditioning-like interventions, the mitochondrial calcium retention capacity significantly increased only in the Post-Iso group (+58 % vs control) after succinate activation. Only Post-Iso increased state 3 (+177 and +62 %, for G/M and succinate, respectively) when compared to control. Also, Post-Iso reduced the hydrogen peroxide (H2O2) production (-46 % vs control) after complex I activation. This study suggests that isoflurane, but not cyclosporine A, can prevent lethal reperfusion injury in this in vivo rat model. This might be related to the need for a combined effect on cyclophilin D and complex I during the first minutes of reperfusion.

Mechanistic review of drug-induced steatohepatitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumacher, Justin D., E-mail: Justin.d.schumacher@rutgers.edu; Guo, Grace L.

Drug-induced steatohepatitis is a rare form of liver injury known to be caused by only a handful of compounds. These compounds stimulate the development of steatohepatitis through their toxicity to hepatocyte mitochondria; inhibition of beta-oxidation, mitochondrial respiration, and/or oxidative phosphorylation. Other mechanisms discussed include the disruption of phospholipid metabolism in lysosomes, prevention of lipid egress from hepatocytes, targeting mitochondrial DNA and topoisomerase, decreasing intestinal barrier function, activation of the adenosine pathway, increasing fatty acid synthesis, and sequestration of coenzyme A. It has been found that the majority of compounds that induce steatohepatitis have cationic amphiphilic structures; a lipophilic ring structuremore » with a side chain containing a cationic secondary or tertiary amine. Within the last decade, the ability of many chemotherapeutics to cause steatohepatitis has become more evident coining the term chemotherapy-associated steatohepatitis (CASH). The mechanisms behind drug-induced steatohepatitis are discussed with a focus on cationic amphiphilic drugs and chemotherapeutic agents. - Highlights: • Reviewed the mechanisms underlying drug-induced steatohepatitis for many compounds • Mitochondrial dysfunction is critical in the development of drug-induced steatohepatitis. • Majority of drugs that induce steatohepatitis are cationic amphiphilic drugs. • Chemotherapeutics that induce CASH are cationic amphiphilic drugs. • Majority of drugs that induce steatohepatitis are carnitine palmitoyltransferase-I inhibitors.« less

Acetaminophen-induced liver injury in rats and mice: Comparison of protein adducts, mitochondrial dysfunction, and oxidative stress in the mechanism of toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGill, Mitchell R.; Williams, C. David; Xie, Yuchao

2012-11-01

Acetaminophen (APAP) overdose is the most common cause of acute liver failure in the West. In mice, APAP hepatotoxicity can be rapidly induced with a single dose. Because it is both clinically relevant and experimentally convenient, APAP intoxication has become a popular model of liver injury. Early data demonstrated that rats are resistant to APAP toxicity. As a result, mice are the preferred species for mechanistic studies. Furthermore, recent work has shown that the mechanisms of APAP toxicity in humans are similar to mice. Nevertheless, some investigators still use rats. New mechanistic information from the last forty years invites amore » reevaluation of the differences between these species. Comparison may provide interesting insights and confirm or exclude the rat as an option for APAP studies. To this end, we treated rats and mice with APAP and measured parameters of liver injury, APAP metabolism, oxidative stress, and activation of the c-Jun N-terminal kinase (JNK). Consistent with earlier data, we found that rats were highly resistant to APAP toxicity. Although overall APAP metabolism was similar in both species, mitochondrial protein adducts were significantly lower in rats. Accordingly, rats also had less oxidative stress. Finally, while mice showed extensive activation and mitochondrial translocation of JNK, this could not be detected in rat livers. These data support the hypothesis that mitochondrial dysfunction is critical for the development of necrosis after APAP treatment. Because mitochondrial damage also occurs in humans, rats are not a clinically relevant species for studies of APAP hepatotoxicity. Highlights: ► Acetaminophen overdose causes severe liver injury only in mice but not in rats. ► APAP causes hepatic GSH depletion and protein adduct formation in rats and mice. ► Less protein adducts were measured in rat liver mitochondria compared to mouse. ► No oxidant stress, peroxynitrite formation or JNK activation was present in rats. ► The limited mitochondrial adducts in rats are insufficient to trigger cell necrosis.« less

The Effects of Difumarate Salt S-15176 after Spinal Cord Injury in Rats

PubMed Central

Tunçdemir, Matem; Kelten, Bilal; Akdemir, Osman; Karaoğlan, Alper; Taşdemiroğlu, Erol

2015-01-01

Objective In the present study we analyzed neuroprotective and antiapoptotic effect of the difumarate salt S-15176, as an anti-ischemic, an antioxidant and a stabilizer of mitochondrial membrane in secondary damage following spinal cord injury (SCI) in a rat model. Methods Three groups were performed with 30 Wistar rats; control (1), trauma (2), and a trauma+S-15176 (10 mg/kg i.p., dimethyl sulfoxide) treatment (3). SCI was performed at the thoracic level using the weight-drop technique. Spinal cord tissues were collected following intracardiac perfusion in 3rd and 7th days of posttrauma. Hematoxylin and eosin staining for histopatology, terminal deoxynucleotidyl transferase dUTP nick end labeling assay for apoptotic cells and immunohistochemistry for proapoptotic cytochrome-c, Bax and caspase 9 were performed to all groups. Functional recovery test were applied to each group in 3rd and 7th days following SCI. Results In trauma group, edematous regions, diffuse hemorrhage, necrosis, leukocyte infiltration and severe degeneration in motor neurons were observed prominently in gray matter. The number of apoptotic cells was significantly higher (p<0.05) than control group. In the S-15176-treated groups, apoptotic cell number in 3rd and 7th days (p<0.001), also cytochrome-c (p<0.001), Bax (p<0.001) and caspase 9 immunoreactive cells (p<0.001) were significantly decreased in number compared to trauma groups. Hemorrhage and edema in the focal areas were also noticed in gray matter of treatment groups. Results of the locomotor test were significantly increased in treatment group (p<0.05) when compared to trauma groups. Conclusion We suggest that difumarate salt S-15176 prevents mitochondrial pathways of apoptosis and protects spinal cord from secondary injury and helps to preserve motor function following SCI in rats. PMID:26180614

Mitochondrial dysfunction as a trigger of innate immune responses and inflammation.

PubMed

West, A Phillip

2017-11-01

A growing literature indicates that mitochondria are key participants in innate immune pathways, functioning as both signaling platforms and contributing to effector responses. In addition to regulating antiviral signaling and antibacterial immunity, mitochondria are also important drivers of inflammation caused by sterile injury. Much research on mitochondrial control of immunity now centers on understanding how mitochondrial constituents released during cellular damage simulate the innate immune system. When mitochondrial integrity is compromised, mitochondrial damage-associated molecular patterns engage pattern recognition receptors, trigger inflammation, and promote pathology in an expanding list of diseases. Here, I review the emerging knowledge of mitochondrial dysfunction in innate immune responses and discuss how environmental exposures may induce mitochondrial damage to potentiate inflammation and human disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of mitochondrial permeability transition pores in mitochondrial autophagy.

PubMed

Rodriguez-Enriquez, Sara; He, Lihua; Lemasters, John J

2004-12-01

During autophagy, cells rid themselves of damaged and superfluous mitochondria, as well as other organelles. This activation of mitochondrial turnover could be the result of changes in the physiological state of mitochondria. Confocal microscopy and fluorescence techniques indicate that onset of mitochondrial permeability transition is one such change. The mitochondrial permeability transition is a reversible phenomenon whereby the mitochondrial inner membrane becomes freely permeable to solutes of less than 1500 Da. At onset of the mitochondrial permeability transition, mitochondria depolarize, uncouple, and undergo large amplitude swelling due to opening of permeability transition pores, which may form by aggregation of damaged, misfolded membrane proteins. When injurious cellular stresses occur, cells may protect themselves using autophagy to remove damaged mitochondria and mutated mitochondrial DNA. Ca(2+) overloading, reactive oxygen and nitrogen species, decreased mitochondrial membrane potential, and oxidation of pyridine nucleotides and glutathione all promote mitochondrial damage and onset of the mitochondrial permeability transition. The mitochondrial permeability transition is also associated with necrosis and apoptosis after a variety of stimuli. This review emphasizes the role of the mitochondrial permeability transition as a key event in mitochondrial autophagy.

Desensitizing Mitochondrial Permeability Transition by ERK-Cyclophilin D Axis Contributes to the Neuroprotective Effect of Gallic Acid against Cerebral Ischemia/Reperfusion Injury

PubMed Central

Sun, Jing; Ren, Da-Dui; Wan, Jin-Yi; Chen, Chen; Chen, Dong; Yang, Huan; Feng, Chun-Lai; Gao, Jing

2017-01-01

Ischemic stroke is a devastating disease with complex pathophysiology. Much evidence confirms that opening of the mitochondrial permeability transition pore (MPTP) is related with mitochondrial dysfunction to apoptosis in ischemic stroke, thus elucidating its signaling mechanism and screening novel MPTP inhibitor is therefore of paramount importance. Our earlier studies identified that gallic acid (GA), a naturally occurring plant phenol, endows with effect on inhibition of mitochondrial dysfunction, which has significant neuroprotective effect in cerebral ischemia/reperfusion injury. However, its molecular mechanisms regulating mitochondrial dysfunction remain elusive. Here, we uncover a role of GA in protecting mitochondria via MPTP inhibition. In addition to inhibit CypD binding to adenine nucleotide translocator, GA potentiates extracellular signal-regulated kinases (ERK) phosphorylation, leading to a decrease in cyclophilin D (CypD) expression, resulting in a desensitization to induction of MPTP, thus inhibiting caspase activation and ultimately giving rise to cellular survival. Our study firstly identifies ERK-CypD axis is one of the cornerstones of the cell death pathways following ischemic stroke, and confirms GA is a novel inhibitor of MPTP, which inhibits apoptosis depending on regulating the ERK-CypD axis. PMID:28428752

TSA protects H9c2 cells against thapsigargin-induced apoptosis related to endoplasmic reticulum stress-mediated mitochondrial injury.

PubMed

Li, Zhiping; Liu, Yan; Dai, Xinlun; Zhou, Qiangqiang; Liu, Xueli; Li, Zeyu; Chen, Xia

2017-05-01

Endoplasmic reticulum stress (ERS) activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. Recently, TSA has shown protective effects on ERS and its mechanisms related to ER pathway has been previously characterized. However, whether TSA exerts its protective role via metabolic events remain largely undefined. Objectives : To explore the possible involvement of the metabolic changes during ERS and to better understand how TSA influence mitochondrial function to facilitate cellular adaptation. Results : TSA is an inhibitor of histone deacetylase which could significantly inhibit H9c2 cell apoptosis induced by Thapsigargin (TG). It also intervene the decrease of mitochondrial membrane potential. By immunofluorescence staining, we have shown that GRP78 was concentrated in the perinuclear region and co-localized with ER. However, treatments with TG and TSA could let it overlap with the mitochondrial marker MitoTracker. Cellular fractionation also confirmed the location of GRP78 in mitochondrion. TSA decreases ERS-induced cell apoptosis and mitochondrial injury may related to enhance the location of GRP78 in mitochondrion.

Thymoquinone Attenuates Myocardial Ischemia/Reperfusion Injury Through Activation of SIRT1 Signaling.

PubMed

Lu, Yunyang; Feng, Yingda; Liu, Dan; Zhang, Zhiran; Gao, Kai; Zhang, Wei; Tang, Haifeng

2018-06-15

Myocardial ischemia/reperfusion (MI/R) injury is a leading factor responsible for damage in myocardial infarction, resulting in additional injury to cardiac tissues involved in oxidative stress, inflammation, and apoptosis. Thymoquinone (TQ), the main constituent of Nigella sativa L. seeds, has been reported to possess various biological activities. However, few reports regarding myocardial protection are available at present. Therefore, this study was conducted aiming to investigate the protective effect of TQ against MI/R injury and to clarify its potential mechanism. MI/R injury models of isolated rat hearts and neonatal rat cardiomyocytes were established. The Langendorff isolated perfused heart system, triphenyltetrazolium chloride staining, gene transfection, TransLaser scanning confocal microscopy, and western blotting were employed to evaluate the cardioprotection effect of TQ against MI/R injury. Compared with the MI/R group, TQ treatment could remarkably improve left ventricular function, decrease myocardial infarct size and production of lactate dehydrogenase (LDH), and attenuate mitochondrial oxidative damage by elevating superoxide dismutase (SOD) activity and reducing production of hydrogen peroxide (H2O2) and malonaldehyde (MDA). Moreover, the cardioprotective effect of TQ was accompanied by up-regulated expression of SIRT1 and inhibition of p53 acetylation. Additionally, TQ treatment could also enhance mitochondrial function and reduce the number of apoptotic cardiomyocytes. Nonetheless, the cardioprotective effect of TQ could be mitigated by SIRT1 inhibitor sirtinol and SIRT1 siRNA, respectively, which was achieved through inhibition of the SIRT1 signaling pathway. The findings in this study demonstrate that TQ is efficient in attenuating MI/R injury through activation of the SIRT1 signaling pathway, which can thus reduce mitochondrial oxidative stress damage and cardiomyocyte apoptosis. © 2018 The Author(s). Published by S. Karger AG, Basel.

The Effect of Propofol on Mitochondrial Fission during Oxygen-Glucose Deprivation and Reperfusion Injury in Rat Hippocampal Neurons.

PubMed

Wang, Haibin; Zheng, Shengfa; Liu, Maodong; Jia, Changxin; Wang, Shilei; Wang, Xue; Xue, Sha; Guo, Yunliang

2016-01-01

The neuroprotective role of propofol in transient global and focal cerebral ischemia reperfusion (I/R) animal model has recently been highlighted. However, no studies have conducted to explore the relationship between mitochondrial fission/fusion and I/R injury under the intervention of propofol. Moreover, neuroprotective mechanism of propofol is yet unclear. Culturing primary hippocampal cells were subjected to oxygen-glucose deprivation and re-oxygenation (OGD/R) model, as a model of cerebral I/R in vitro. Methods CCK-8 assay was used to test the effect of propofol on cell viability. We examined the effect of propofol on mitochondrial ultrastructure and mitochondrial fission evoked by OGD/R with transmission electron microscopy and immunofluorescence assay. To investigate possible neuroprotective mechanisms, the authors then examined whether propofol could inhibit calcium-overload, calcineurin (CaN) activation and the phosphorylation of dynamin-related protein 1 (Drp1) during the period of OGD/R, as well as the combination of Drp1-ser 637 and fission 1 (Fis1) protein by immunofluorescence assay, ELISA and double-labeling immunofluorescence analysis. Finally, the expression of Drp1-ser 637 and Fis1, apoptosis inducing factor (AIF) and cytochrome C (Cyt C) were detected by western blot. When added in culture media during OGD period, propofol (0.1μM-50μM) could alleviate neurons injury and protect mitochondrial ultrastructure, meanwhile inhibit mitochondrial fission. Furthermore, the concentration of intracellular free Ca2+, CaN activition and the phosphorylation of Drp1-ser637 were suppressed, as well as the translocation and combination of Drp1-ser 637 and Fis1. The authors also found that the expression of Cyt C, AIF, Drp1-ser637 and Fis1 were down-regulated. Notably, high dose of propofol (100μM-200μM) were confirmed to decrease the survival of neurons based on results of cell viability. Propofol could inhibit mitochondrial fission and mitochondrial apoptotic pathway evoked by OGD/R in rat hippocampal neurons, which may be via depressing calcium-overload.

Vascular calcification abrogates the nicorandil mediated cardio-protection in ischemia reperfusion injury of rat heart.

PubMed

Ravindran, Sriram; Murali, Jeyashri; Amirthalingam, Sunil Kumar; Gopalakrishnan, Senthilkumar; Kurian, Gino A

2017-02-01

The present study was aimed to determine the efficacy of nicorandil in treating cardiac reperfusion injury with an underlying co-morbidity of vascular calcification (VC). Adenine diet was used to induce VC in Wistar rat and the heart was isolated to induce global ischemia reperfusion (IR) by Langendorff method, with and without the nicorandil (7.5mg/kg) pre-treatment and compared with those fed on normal diet. The adenine-treated rats displayed abnormal ECG changes and altered mitochondrial integrity compared to a normal rat heart. These hearts, when subjected to IR increased the infarct size, cardiac injury (measured by lactate dehydrogenase and creatine kinase activity in the coronary perfusate) and significantly altered the hemodynamics compared to the normal perfused heart. Nicorandil pretreatment in rat fed on normal diet enhanced the hemodynamics significantly (P<0.05) along with a substantial reduction in the mitochondrial dysfunction (measured by high ADP to oxygen consumption ratio, respiratory control ratio, enzyme activities and less swelling behavior) when subjected to IR. However, this cardio-protective effect of nicorandil was absent in rat heart with underlying calcification. Our results suggest that, the protective effect of nicorandil, a known mitochondrial ATP linked K + channel opener, against myocardial reperfusion injury was confined to normal rat heart. Copyright © 2017 Elsevier Inc. All rights reserved.

Deferasirox-induced iron depletion promotes BclxL downregulation and death of proximal tubular cells

PubMed Central

Martin-Sanchez, Diego; Gallegos-Villalobos, Angel; Fontecha-Barriuso, Miguel; Carrasco, Susana; Sanchez-Niño, Maria Dolores; Lopez-Hernandez, Francisco J; Ruiz-Ortega, Marta; Egido, Jesus; Ortiz, Alberto; Sanz, Ana Belén

2017-01-01

Iron deficiency has been associated with kidney injury. Deferasirox is an oral iron chelator used to treat blood transfusion-related iron overload. Nephrotoxicity is the most serious and common adverse effect of deferasirox and may present as an acute or chronic kidney disease. However, scarce data are available on the molecular mechanisms of nephrotoxicity. We explored the therapeutic modulation of deferasirox-induced proximal tubular cell death in culture. Deferasirox induced dose-dependent tubular cell death and AnexxinV/7AAD staining showed features of apoptosis and necrosis. However, despite inhibiting caspase-3 activation, the pan-caspase inhibitor zVAD-fmk failed to prevent deferasirox-induced cell death. Moreover, zVAD increased deferasirox-induced cell death, a feature sometimes found in necroptosis. Electron microscopy identified mitochondrial injury and features of necrosis. However, neither necrostatin-1 nor RIP3 knockdown prevented deferasirox-induced cell death. Deferasirox caused BclxL depletion and BclxL overexpression was protective. Preventing iron depletion protected from BclxL downregulation and deferasirox cytotoxicity. In conclusion, deferasirox promoted iron depletion-dependent cell death characterized by BclxL downregulation. BclxL overexpression was protective, suggesting a role for BclxL downregulation in iron depletion-induced cell death. This information may be used to develop novel nephroprotective strategies. Furthermore, it supports the concept that monitoring kidney tissue iron depletion may decrease the risk of deferasirox nephrotoxicity. PMID:28139717

Deferasirox-induced iron depletion promotes BclxL downregulation and death of proximal tubular cells.

PubMed

Martin-Sanchez, Diego; Gallegos-Villalobos, Angel; Fontecha-Barriuso, Miguel; Carrasco, Susana; Sanchez-Niño, Maria Dolores; Lopez-Hernandez, Francisco J; Ruiz-Ortega, Marta; Egido, Jesus; Ortiz, Alberto; Sanz, Ana Belén

2017-01-31

Iron deficiency has been associated with kidney injury. Deferasirox is an oral iron chelator used to treat blood transfusion-related iron overload. Nephrotoxicity is the most serious and common adverse effect of deferasirox and may present as an acute or chronic kidney disease. However, scarce data are available on the molecular mechanisms of nephrotoxicity. We explored the therapeutic modulation of deferasirox-induced proximal tubular cell death in culture. Deferasirox induced dose-dependent tubular cell death and AnexxinV/7AAD staining showed features of apoptosis and necrosis. However, despite inhibiting caspase-3 activation, the pan-caspase inhibitor zVAD-fmk failed to prevent deferasirox-induced cell death. Moreover, zVAD increased deferasirox-induced cell death, a feature sometimes found in necroptosis. Electron microscopy identified mitochondrial injury and features of necrosis. However, neither necrostatin-1 nor RIP3 knockdown prevented deferasirox-induced cell death. Deferasirox caused BclxL depletion and BclxL overexpression was protective. Preventing iron depletion protected from BclxL downregulation and deferasirox cytotoxicity. In conclusion, deferasirox promoted iron depletion-dependent cell death characterized by BclxL downregulation. BclxL overexpression was protective, suggesting a role for BclxL downregulation in iron depletion-induced cell death. This information may be used to develop novel nephroprotective strategies. Furthermore, it supports the concept that monitoring kidney tissue iron depletion may decrease the risk of deferasirox nephrotoxicity.

Tauroursodeoxycholic Acid Protects Against Mitochondrial Dysfunction and Cell Death via Mitophagy in Human Neuroblastoma Cells.

PubMed

Fonseca, Inês; Gordino, Gisela; Moreira, Sara; Nunes, Maria João; Azevedo, Carla; Gama, Maria João; Rodrigues, Elsa; Rodrigues, Cecília Maria Pereira; Castro-Caldas, Margarida

2017-10-01

Mitochondrial dysfunction has been deeply implicated in the pathogenesis of several neurodegenerative diseases. Thus, to keep a healthy mitochondrial population, a balanced mitochondrial turnover must be achieved. Tauroursodeoxycholic acid (TUDCA) is neuroprotective in various neurodegenerative disease models; however, the mechanisms involved are still incompletely characterized. In this study, we investigated the neuroprotective role of TUDCA against mitochondrial damage triggered by the mitochondrial uncoupler carbonyl cyanide m-chlorophelyhydrazone (CCCP). Herein, we show that TUDCA significantly prevents CCCP-induced cell death, ROS generation, and mitochondrial damage. Our results indicate that the neuroprotective role of TUDCA in this cell model is mediated by parkin and depends on mitophagy. The demonstration that pharmacological up-regulation of mitophagy by TUDCA prevents neurodegeneration provides new insights for the use of TUDCA as a modulator of mitochondrial activity and turnover, with implications in neurodegenerative diseases.

The mitochondria-targeted antioxidant MitoQ ameliorated tubular injury mediated by mitophagy in diabetic kidney disease via Nrf2/PINK1.

PubMed

Xiao, Li; Xu, Xiaoxuan; Zhang, Fan; Wang, Ming; Xu, Yan; Tang, Dan; Wang, Jiahui; Qin, Yan; Liu, Yu; Tang, Chengyuan; He, Liyu; Greka, Anna; Zhou, Zhiguang; Liu, Fuyou; Dong, Zheng; Sun, Lin

2017-04-01

Mitochondria play a crucial role in tubular injury in diabetic kidney disease (DKD). MitoQ is a mitochondria-targeted antioxidant that exerts protective effects in diabetic mice, but the mechanism underlying these effects is not clear. We demonstrated that mitochondrial abnormalities, such as defective mitophagy, mitochondrial reactive oxygen species (ROS) overexpression and mitochondrial fragmentation, occurred in the tubular cells of db/db mice, accompanied by reduced PINK and Parkin expression and increased apoptosis. These changes were partially reversed following an intraperitoneal injection of mitoQ. High glucose (HG) also induces deficient mitophagy, mitochondrial dysfunction and apoptosis in HK-2 cells, changes that were reversed by mitoQ. Moreover, mitoQ restored the expression, activity and translocation of HG-induced NF-E2-related factor 2 (Nrf2) and inhibited the expression of Kelch-like ECH-associated protein (Keap1), as well as the interaction between Nrf2 and Keap1. The reduced PINK and Parkin expression noted in HK-2 cells subjected to HG exposure was partially restored by mitoQ. This effect was abolished by Nrf2 siRNA and augmented by Keap1 siRNA. Transfection with Nrf2 siRNA or PINK siRNA in HK-2 cells exposed to HG conditions partially blocked the effects of mitoQ on mitophagy and tubular damage. These results suggest that mitoQ exerts beneficial effects on tubular injury in DKD via mitophagy and that mitochondrial quality control is mediated by Nrf2/PINK. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Cell Cycle Regulators Guide Mitochondrial Activity in Radiation-Induced Adaptive Response

PubMed Central

Alexandrou, Aris T.

2014-01-01

Abstract Significance: There are accruing concerns on potential genotoxic agents present in the environment including low-dose ionizing radiation (LDIR) that naturally exists on earth's surface and atmosphere and is frequently used in medical diagnosis and nuclear industry. Although its long-term health risk is being evaluated and remains controversial, LDIR is shown to induce temporary but significant adaptive responses in mammalian cells and animals. The mechanisms guiding the mitochondrial function in LDIR-induced adaptive response represent a unique communication between DNA damage and cellular metabolism. Elucidation of the LDIR-regulated mitochondrial activity may reveal new mechanisms adjusting cellular function to cope with hazardous environmental stress. Recent Advances: Key cell cycle regulators, including Cyclin D1/CDK4 and Cyclin B1/cyclin-dependent kinase 1 (CDK1) complexes, are actively involved in the regulation of mitochondrial functions via phosphorylation of their mitochondrial targets. Accumulating new evidence supports a concept that the Cyclin B1/CDK1 complex acts as a mediator in the cross talk between radiation-induced DNA damage and mitochondrial functions to coordinate cellular responses to low-level genotoxic stresses. Critical Issues: The LDIR-mediated mitochondrial activity via Cyclin B1/CDK1 regulation is an irreplaceable network that is able to harmonize vital cellular functions with adjusted mitochondrial metabolism to enhance cellular homeostasis. Future Directions: Further investigation of the coordinative mechanism that regulates mitochondrial activities in sublethal stress conditions, including LDIR, will reveal new insights of how cells cope with genotoxic injury and will be vital for future targeted therapeutic interventions that reduce environmental injury and cancer risk. Antioxid. Redox Signal. 20, 1463–1480. PMID:24180340

Carbon monoxide alleviates lipopolysaccharide-induced oxidative stress injury through suppressing the expression of Fis1 in NR8383 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Jia; Yu, Jian-bo, E-mail: yujianbo11@126.com; Liu, Wei

Acute respiratory distress syndrome (ARDS) is one of the most devastating complications of sepsis lacking of effective therapy. Mitochondrial dynamics undergoing continuous fusion and fission play a crucial role in mitochondrial structure and function. Fis1, as a small protein located on the outer membrane of mitochondria, has been thought to be an important protein mediated mitochondrial fission. During ARDS, alveolar macrophages suffer from increased oxidative stress and apoptosis, and also accompanied by disrupted mitochondrial dynamics. In addition, as one of the products of heme degradation catalyzed by heme oxygenase, carbon monoxide (CO) possesses powerful protective properties in vivo or inmore » vitro models, such as anti-inflammatory, antioxidant and anti-apoptosis function. However, there is little evidence that CO alleviates oxidative stress damage through altering mitochondrial fission in alveolar macrophages. In the present study, our results showed that CO increased cell vitality, improved mitochondrial SOD activity, reduced reactive oxygen species (ROS) production and inhibited cell apoptosis in NR8383 exposed to LPS. Meanwhile, CO decreased the expression of Fis1, increased mitochondrial membrane potential and sustained elongation of mitochondria in LPS-incubated NR8383. Overall, our study underscored a critical role of CO in suppressing the expression of Fis1 and alleviating LPS- induced oxidative stress damage in alveolar macrophages. - Highlights: • LPS exposure triggered cell injury in NR8383. • CO alleviated LPS-induced oxidative stress damage in alveolar macrophages. • CO inhibited Fis1 levels and improved mitochondrial function in LPS-induced NR8383.« less

SIRT3 protects hepatocytes from oxidative injury by enhancing ROS scavenging and mitochondrial integrity

USDA-ARS?s Scientific Manuscript database

Evidences of oxidative stress and mitochondrial dysfunction have been recognized in most of clinical and experimental liver diseases. SIRT3, a member of NAD+-dependent deacetylases, is mainly localized in mitochondria. So far, the role of SIRT3 in protecting hepatocytes against oxidative stress rema...

Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage.

PubMed

Kim, Seok-Jo; Cheresh, Paul; Jablonski, Renea P; Morales-Nebreda, Luisa; Cheng, Yuan; Hogan, Erin; Yeldandi, Anjana; Chi, Monica; Piseaux, Raul; Ridge, Karen; Michael Hart, C; Chandel, Navdeep; Scott Budinger, G R; Kamp, David W

2016-12-01

Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. Crocidolite asbestos (100µg/50µL), TiO 2 (negative control), bleomycin (0.025 units/50µL), or PBS was instilled intratracheally in 8-10 week-old wild-type (WT - C57Bl/6J) or MCAT mice. The lungs were harvested at 21d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H 2 O 2 -induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H 2 O 2 production may be a novel therapeutic target for mitigating pulmonary fibrosis. Published by Elsevier Inc.

Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage

PubMed Central

Kim, Seok-Jo; Cheresh, Paul; Jablonski, Renea P.; Morales-Nebreda, Luisa; Cheng, Yuan; Hogan, Erin; Yeldandi, Anjana; Chi, Monica; Piseaux, Raul; Ridge, Karen; Hart, C. Michael; Chandel, Navdeep; Budinger, G.R. Scott; Kamp, David W.

2018-01-01

Rationale Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. Objective To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. Methods Crocidolite asbestos (100 μg/50 μL), TiO2 (negative control), bleomycin (0.025 units/50 μL), or PBS was instilled intratracheally in 8–10 week-old wild-type (WT - C57Bl/6 J) or MCAT mice. The lungs were harvested at 21 d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. Results Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. Conclusions Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H2O2-induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H2O2 production may be a novel therapeutic target for mitigating pulmonary fibrosis. PMID:27840320

Myocardial Ablation of G Protein-Coupled Receptor Kinase 2 (GRK2) Decreases Ischemia/Reperfusion Injury through an Anti-Intrinsic Apoptotic Pathway.

PubMed

Fan, Qian; Chen, Mai; Zuo, Lin; Shang, Xiying; Huang, Maggie Z; Ciccarelli, Michele; Raake, Philip; Brinks, Henriette; Chuprun, Kurt J; Dorn, Gerald W; Koch, Walter J; Gao, Erhe

2013-01-01

Studies from our lab have shown that decreasing myocardial G protein-coupled receptor kinase 2 (GRK2) activity and expression can prevent heart failure progression after myocardial infarction. Since GRK2 appears to also act as a pro-death kinase in myocytes, we investigated the effect of cardiomyocyte-specific GRK2 ablation on the acute response to cardiac ischemia/reperfusion (I/R) injury. To do this we utilized two independent lines of GRK2 knockout (KO) mice where the GRK2 gene was deleted in only cardiomyocytes either constitutively at birth or in an inducible manner that occurred in adult mice prior to I/R. These GRK2 KO mice and appropriate control mice were subjected to a sham procedure or 30 min of myocardial ischemia via coronary artery ligation followed by 24 hrs reperfusion. Echocardiography and hemodynamic measurements showed significantly improved post-I/R cardiac function in both GRK2 KO lines, which correlated with smaller infarct sizes in GRK2 KO mice compared to controls. Moreover, there was significantly less TUNEL positive myocytes, less caspase-3, and -9 but not caspase-8 activities in GRK2 KO mice compared to control mice after I/R injury. Of note, we found that lowering cardiac GRK2 expression was associated with significantly lower cytosolic cytochrome C levels in both lines of GRK2 KO mice after I/R compared to corresponding control animals. Mechanistically, the anti-apoptotic effects of lowering GRK2 expression were accompanied by increased levels of Bcl-2, Bcl-xl, and increased activation of Akt after I/R injury. These findings were reproduced in vitro in cultured cardiomyocytes and GRK2 mRNA silencing. Therefore, lowering GRK2 expression in cardiomyocytes limits I/R-induced injury and improves post-ischemia recovery by decreasing myocyte apoptosis at least partially via Akt/Bcl-2 mediated mitochondrial protection and implicates mitochondrial-dependent actions, solidifying GRK2 as a pro-death kinase in the heart.

Ginkgo Biloba Ameliorates Subfertility Induced by Testicular Ischemia/Reperfusion Injury in Adult Wistar Rats: A Possible New Mitochondrial Mechanism

PubMed Central

Ahmed, Asmaa Ibrahim; El-Zawahry, Khaled Mohamed

2016-01-01

Testicular torsion, a surgical emergency, could affect the endocrine and exocrine testicular functions. This study demonstrates histopathological and physiological effects of testicular ischemia/perfusion (I/R) injury and the possible protective effects of Ginkgo biloba treatment. Fifty adult male Wistar rats, 180–200 gm, were randomly divided into sham-operated, Gingko biloba supplemented, ischemia only, I/R, and Gingko biloba treated I/R groups. Overnight fasted rats were anaesthetized by Pentobarbital; I/R was performed by left testis 720° rotation in I/R and treated I/R groups. Orchiectomy was performed for histopathological studies and detection of mitochondrial NAD+. Determination of free testosterone, FSH, TNF-α, and IL1-β in plasma was performed. Plasma-free testosterone was significantly decreased, while plasma FSH, TNF-α, IL-1β, and testicular mitochondrial NAD+ were significantly increased in I/R group compared to control group. These parameters were reversed in Gingko biloba treated I/R group compared to I/R group. I/R caused marked testicular damage and increased APAF-1 in the apoptotic cells which were reversed by Ginkgo biloba treatment. It could be concluded that I/R caused subfertility induced by apoptosis and oxidative stress manifested by the elevated testicular mitochondrial NAD+, which is considered a new possible mechanism. Also, testicular injury could be reduced by Gingko biloba administration alone. PMID:28101298

Ginkgo Biloba Ameliorates Subfertility Induced by Testicular Ischemia/Reperfusion Injury in Adult Wistar Rats: A Possible New Mitochondrial Mechanism.

PubMed

Ahmed, Asmaa Ibrahim; Lasheen, Noha N; El-Zawahry, Khaled Mohamed

2016-01-01

Testicular torsion, a surgical emergency, could affect the endocrine and exocrine testicular functions. This study demonstrates histopathological and physiological effects of testicular ischemia/perfusion (I/R) injury and the possible protective effects of Ginkgo biloba treatment. Fifty adult male Wistar rats, 180-200 gm, were randomly divided into sham-operated, Gingko biloba supplemented, ischemia only, I/R, and Gingko biloba treated I/R groups. Overnight fasted rats were anaesthetized by Pentobarbital; I/R was performed by left testis 720° rotation in I/R and treated I/R groups. Orchiectomy was performed for histopathological studies and detection of mitochondrial NAD + . Determination of free testosterone, FSH, TNF- α , and IL1- β in plasma was performed. Plasma-free testosterone was significantly decreased, while plasma FSH, TNF- α , IL-1 β , and testicular mitochondrial NAD + were significantly increased in I/R group compared to control group. These parameters were reversed in Gingko biloba treated I/R group compared to I/R group. I/R caused marked testicular damage and increased APAF-1 in the apoptotic cells which were reversed by Ginkgo biloba treatment. It could be concluded that I/R caused subfertility induced by apoptosis and oxidative stress manifested by the elevated testicular mitochondrial NAD + , which is considered a new possible mechanism. Also, testicular injury could be reduced by Gingko biloba administration alone.

YiXin-Shu, a ShengMai-San-based traditional Chinese medicine formula, attenuates myocardial ischemia/reperfusion injury by suppressing mitochondrial mediated apoptosis and upregulating liver-X-receptor α.

PubMed

Zhao, Yichao; Xu, Longwei; Qiao, Zhiqing; Gao, Lingchen; Ding, Song; Ying, Xiaoying; Su, Yuanyuan; Lin, Nan; He, Ben; Pu, Jun

2016-03-11

Positive evidence from clinical trials has fueled growing acceptance of traditional Chinese medicine (TCM) for the treatment of cardiac diseases; however, little is known about the underlying mechanisms. Here, we investigated the nature and underlying mechanisms of the effects of YiXin-Shu (YXS), an antioxidant-enriched TCM formula, on myocardial ischemia/reperfusion (MI/R) injury. YXS pretreatment significantly reduced infarct size and improved viable myocardium metabolism and cardiac function in hypercholesterolemic mice. Mechanistically, YXS attenuated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway (as reflected by inhibition of mitochondrial swelling, cytochrome c release and caspase-9 activity, and normalization of Bcl-2 and Bax levels) without altering the death receptor and endoplasmic reticulum-stress death pathways. Moreover, YXS reduced oxidative/nitrative stress (as reflected by decreased superoxide and nitrotyrosine content and normalized pro- and anti-oxidant enzyme levels). Interestingly, YXS upregulated endogenous nuclear receptors including LXRα, PPARα, PPARβ and ERα, and in-vivo knockdown of cardiac-specific LXRα significantly blunted the cardio-protective effects of YXS. Collectively, these data show that YXS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and oxidative stress and by upregulating LXRα, thereby providing a rationale for future clinical trials and clinical applications.

Mitochondrial DNA Unwinding Enzyme Required for Liver Regeneration | Center for Cancer Research

Cancer.gov

The liver has an exceptional capacity to proliferate. This ability allows the liver to regenerate its mass after partial surgical removal or injury and is the key to successful partial liver transplants. Liver cells, called hepatocytes, are packed with mitochondria, and regulating mitochondrial DNA (mtDNA) copy number is crucial to mitochondrial function, including energy production, during proliferation. Yves Pommier, M.D., Ph.D., of CCR’s Developmental Therapeutics Branch, and his colleagues recently showed that the vertebrate mitochondrial topoisomerase, Top1mt, was critical in maintaining mitochondrial function in the heart after doxorubicin-induced damage. The group wondered whether Top1mt might play a similar role in liver regeneration.

CORM-A1 prevents blood-brain barrier dysfunction caused by ionotropic glutamate receptor-mediated endothelial oxidative stress and apoptosis.

PubMed

Basuroy, Shyamali; Leffler, Charles W; Parfenova, Helena

2013-06-01

In cerebral microvascular endothelial cells (CMVEC) of newborn pigs, glutamate at excitotoxic concentrations (mM) causes apoptosis mediated by reactive oxygen species (ROS). Carbon monoxide (CO) produced by CMVEC or delivered by a CO-releasing molecule, CORM-A1, has antioxidant properties. We tested the hypothesis that CORM-A1 prevents cerebrovascular endothelial barrier dysfunction caused by glutamate excitotoxicity. First, we identified the glutamate receptors (GluRs) and enzymatic sources of ROS involved in the mechanism of endothelial apoptosis. In glutamate-exposed CMVEC, ROS formation and apoptosis were blocked by rotenone, 2-thenoyltrifluoroacetone (TTFA), and antimycin, indicating that mitochondrial complexes I, II, and III are the major sources of oxidative stress. Agonists of ionotropic GluRs (iGluRs) N-methyl-D-aspartate (NMDA), cis-ACPD, AMPA, and kainate increased ROS production and apoptosis, whereas iGluR antagonists exhibited antiapoptotic properties, suggesting that iGluRs mediate glutamate-induced endothelial apoptosis. The functional consequences of endothelial injury were tested in the model of blood-brain barrier (BBB) composed of CMVEC monolayer on semipermeable membranes. Glutamate and iGluR agonists reduced transendothelial electrical resistance and increased endothelial paracellular permeability to 3-kDa dextran. CORM-A1 exhibited potent antioxidant and antiapoptotic properties in CMVEC and completely prevented BBB dysfunction caused by glutamate and iGluR agonists. Overall, the endothelial component of the BBB is a cellular target for excitotoxic glutamate that, via a mechanism involving a iGluR-mediated activation of mitochondrial ROS production and apoptosis, leads to BBB opening that may be prevented by the antioxidant and antiapoptotic actions of CORMs. Antioxidant CORMs therapy may help preserve BBB functional integrity in neonatal cerebrovascular disease.

AP39, a mitochondria‐targeting hydrogen sulfide (H2S) donor, protects against myocardial reperfusion injury independently of salvage kinase signalling

PubMed Central

Karwi, Qutuba G; Bornbaum, Julia; Boengler, Kerstin; Torregrossa, Roberta; Whiteman, Matthew; Wood, Mark E; Schulz, Rainer

2017-01-01

Background and Purpose H2S protects myocardium against ischaemia/reperfusion injury. This protection may involve the cytosolic reperfusion injury salvage kinase (RISK) pathway, but direct effects on mitochondrial function are possible. Here, we investigated the potential cardioprotective effect of a mitochondria‐specific H2S donor, AP39, at reperfusion against ischaemia/reperfusion injury. Experimental Approach Anaesthetized rats underwent myocardial ischaemia (30 min)/reperfusion (120 min) with randomization to receive interventions before reperfusion: vehicle, AP39 (0.01, 0.1, 1 μmol·kg−1), or control compounds AP219 and ADT‐OH (1 μmol·kg−1). LY294002, L‐NAME or ODQ were used to investigate the involvement of the RISK pathway. Myocardial samples harvested 5 min after reperfusion were analysed for RISK protein phosphorylation and isolated cardiac mitochondria were used to examine the direct mitochondrial effects of AP39. Key Results AP39, dose‐dependently, reduced infarct size. Inhibition of either PI3K/Akt, eNOS or sGC did not affect this effect of AP39. Western blot analysis confirmed that AP39 did not induce phosphorylation of Akt, eNOS, GSK‐3β or ERK1/2. In isolated subsarcolemmal and interfibrillar mitochondria, AP39 significantly attenuated mitochondrial ROS generation without affecting respiratory complexes I or II. Furthermore, AP39 inhibited mitochondrial permeability transition pore (PTP) opening and co‐incubation of mitochondria with AP39 and cyclosporine A induced an additive inhibitory effect on the PTP. Conclusion and Implications AP39 protects against reperfusion injury independently of the cytosolic RISK pathway. This cardioprotective effect could be mediated by inhibiting PTP via a cyclophilin D‐independent mechanism. Thus, selective delivery of H2S to mitochondria may be therapeutically applicable for employing the cardioprotective utility of H2S. PMID:27930802

Protective effects of propofol against whole cerebral ischemia/reperfusion injury in rats through the inhibition of the apoptosis-inducing factor pathway.

PubMed

Tao, Tao; Li, Chun-Lei; Yang, Wan-Chao; Zeng, Xian-Zhang; Song, Chun-Yu; Yue, Zi-Yong; Dong, Hong; Qian, Hua

2016-08-01

Cerebral ischemia/reperfusion (I/R) injury could cause neural apoptosis that involved the signaling cascades. Cytochrome c release from the mitochondria and the followed activation of caspase 9 and caspase 3 are the important steps. Now, a new mitochondrial protein, apoptosis-inducing factor (AIF), has been shown to have relationship with the caspase-independent apoptotic pathway. In this study, we investigated the protective effects of propofol through inhibiting AIF-mediated apoptosis induced by whole cerebral I/R injury in rats. 120 Wistar rats that obtained the permission of the animal care committee of Harbin Medical University were randomly divided into three groups: sham group (S group), cerebral ischemia/reperfusion injury group (I/R group), and propofol treatment group (P group). Propofol (1.0mg/kg/min) was administered intravenously for 1h before the induction of ischemia in P group. The apoptotic rate in three groups was detected by flow cytometry after 24h of reperfusion. The mitochondrial membrane potential (MMP) changes were detected via microplate reader. The expressions of B-cell leukemia-2 (Bcl-2), Bcl-2 associated X protein (Bax) and AIF were evaluated using Western blot after 6h, 24h and 48h of reperfusion. The results of our study showed that apoptotic level was lower in P group compared with I/R group and propofol could protect MMP. The ratio of Bcl-2/Bax was significantly higher in P group compared with I/R group. The translocation of AIF from mitochondrial to nucleus was lower in P group than that in I/R group. Our findings suggested that the protective effects of propofol on cerebral I/R injury might be associated with inhibiting translocation of AIF from mitochondrial to the nucleus in hippocampal neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Coenzyme Q10 Protects Human Endothelial Cells from β-Amyloid Uptake and Oxidative Stress-Induced Injury

PubMed Central

Durán-Prado, Mario; Frontiñán, Javier; Santiago-Mora, Raquel; Peinado, Juan Ramón; Parrado-Fernández, Cristina; Gómez-Almagro, María Victoria; Moreno, María; López-Domínguez, José Alberto; Villalba, José Manuel; Alcaín, Francisco J.

2014-01-01

Neuropathological symptoms of Alzheimer's disease appear in advances stages, once neuronal damage arises. Nevertheless, recent studies demonstrate that in early asymptomatic stages, ß-amyloid peptide damages the cerebral microvasculature through mechanisms that involve an increase in reactive oxygen species and calcium, which induces necrosis and apoptosis of endothelial cells, leading to cerebrovascular dysfunction. The goal of our work is to study the potential preventive effect of the lipophilic antioxidant coenzyme Q (CoQ) against ß-amyloid-induced damage on human endothelial cells. We analyzed the protective effect of CoQ against Aβ-induced injury in human umbilical vein endothelial cells (HUVECs) using fluorescence and confocal microscopy, biochemical techniques and RMN-based metabolomics. Our results show that CoQ pretreatment of HUVECs delayed Aβ incorporation into the plasma membrane and mitochondria. Moreover, CoQ reduced the influx of extracellular Ca2+, and Ca2+ release from mitochondria due to opening the mitochondrial transition pore after β-amyloid administration, in addition to decreasing O2 .− and H2O2 levels. Pretreatment with CoQ also prevented ß-amyloid-induced HUVECs necrosis and apoptosis, restored their ability to proliferate, migrate and form tube-like structures in vitro, which is mirrored by a restoration of the cell metabolic profile to control levels. CoQ protected endothelial cells from Aβ-induced injury at physiological concentrations in human plasma after oral CoQ supplementation and thus could be a promising molecule to protect endothelial cells against amyloid angiopathy. PMID:25272163

Role of mitochondria in paricalcitol-mediated cytoprotection during obstructive nephropathy

PubMed Central

García, Isabel Mercedes; Altamirano, Liliana; Mazzei, Luciana; Fornés, Miguel; Molina, Marisa Nile; Ferder, León

2012-01-01

Vitamin D slows the progression of chronic kidney disease. Furthermore, activators of vitamin D receptors (VDR) have suppressant effects on the renin-angiotensin system, as well as anti-inflammatory and antifibrotic actions. This study aimed to evaluate the cytoprotective effects of paricalcitol, a VDR activator, at the mitochondrial level using an obstructive nephropathy model [unilateral ureteral obstruction (UUO)]. Rats subjected to UUO and controls were treated daily with vehicle or paricalcitol. The control group underwent a sham surgery. The treatment was done for 15 days (30 ng/kg). The following were determined: biochemical parameters; fibrosis; apoptosis; mitochondrial morphology; VDR, AT1 receptor, and NADPH oxidase 4 expression; and NADPH oxidase activity (in total and in mitochondrial fractions from the renal cortex). VDR activation prevented fibrosis (20 ± 5 vs. 60 ± 10%) and the number of TUNEL-positive apoptotic cells (10 ± 3 vs. 25 ± 4) in UUO. Biochemical, histological, and molecular studies suggest mitochondrial injury. Electron microscopy revealed in UUO electronically luminous material in the nucleus. Some mitochondria were increased in size and contained dilated crests and larger than normal spaces in their interiors. These changes were not present with paricalcitol treatment. Additionally, high AT1-receptor mRNA and NADPH activity was reverted in mitochondrial fractions from obstructed paricalcitol-treated animals (0.58 ± 0.06 vs. 0.95 ± 0.05 relative densitometry units and 9,000 ± 800 vs. 15,000 ± 1,000 relative fluorescence units·μg protein−1·min−1, respectively). These changes were consistent with an improvement in VDR expression (0.75 ± 0.05 vs. 0.35 ± 0.04 relative densitometry units). These results suggest that paricalcitol confers a protective effect and reveal, as well, a possible AT1 receptor-dependent protective effect that occurs at the mitochondrial level. PMID:22492946

Mitochondria-Targeted Antioxidant Prevents Cardiac Dysfunction Induced by Tafazzin Gene Knockdown in Cardiac Myocytes

PubMed Central

He, Quan; Harris, Nicole; Ren, Jun; Han, Xianlin

2014-01-01

Tafazzin, a mitochondrial acyltransferase, plays an important role in cardiolipin side chain remodeling. Previous studies have shown that dysfunction of tafazzin reduces cardiolipin content, impairs mitochondrial function, and causes dilated cardiomyopathy in Barth syndrome. Reactive oxygen species (ROS) have been implicated in the development of cardiomyopathy and are also the obligated byproducts of mitochondria. We hypothesized that tafazzin knockdown increases ROS production from mitochondria, and a mitochondria-targeted antioxidant prevents tafazzin knockdown induced mitochondrial and cardiac dysfunction. We employed cardiac myocytes transduced with an adenovirus containing tafazzin shRNA as a model to investigate the effects of the mitochondrial antioxidant, mito-Tempo. Knocking down tafazzin decreased steady state levels of cardiolipin and increased mitochondrial ROS. Treatment of cardiac myocytes with mito-Tempo normalized tafazzin knockdown enhanced mitochondrial ROS production and cellular ATP decline. Mito-Tempo also significantly abrogated tafazzin knockdown induced cardiac hypertrophy, contractile dysfunction, and cell death. We conclude that mitochondria-targeted antioxidant prevents cardiac dysfunction induced by tafazzin gene knockdown in cardiac myocytes and suggest mito-Tempo as a potential therapeutic for Barth syndrome and other dilated cardiomyopathies resulting from mitochondrial oxidative stress. PMID:25247053

S-52, a novel nootropic compound, protects against β-amyloid induced neuronal injury by attenuating mitochondrial dysfunction.

PubMed

Gao, Xin; Zheng, Chun Yan; Qin, Guo Wei; Tang, Xi Can; Zhang, Hai Yan

2012-10-01

Accumulating evidence suggests that β-amyloid (Aβ)-induced oxidative DNA damage and mitochondrial dysfunction may initiate and contribute to the progression of Alzheimer's disease (AD). This study evaluated the neuroprotective effects of S-52, a novel nootropic compound, on Aβ-induced mitochondrial failure. In an established paradigm of moderate cellular injury induced by Aβ, S-52 was observed to attenuate the toxicity of Aβ to energy metabolism, mitochondrial membrane structure, and key enzymes in the electron transport chain and tricarboxylic acid cycle. In addition, S-52 also effectively inhibited reactive oxygen species accumulation dose dependently not only in Aβ-harmed cells but also in unharmed, normal cells. The role of S-52 as a scavenger of free radicals is involved in the antioxidative effect of this compound. The beneficial effects on mitochondria and oxidative stress extend the neuroprotective effects of S-52. The present study provides crucial information for better understanding the beneficial profiles of this compound and discovering novel potential drug candidates for AD therapy. Copyright © 2012 Wiley Periodicals, Inc.

Melatonin pretreatment enhances the therapeutic effects of exogenous mitochondria against hepatic ischemia-reperfusion injury in rats through suppression of mitochondrial permeability transition.

PubMed

Chen, Hong-Hwa; Chen, Yen-Ta; Yang, Chih-Chao; Chen, Kuan-Hung; Sung, Pei-Hsun; Chiang, Hsin-Ju; Chen, Chih-Hung; Chua, Sarah; Chung, Sheng-Ying; Chen, Yi-Ling; Huang, Tien-Hung; Kao, Gour-Shenq; Chen, Sheng-Yi; Lee, Mel S; Yip, Hon-Kan

2016-08-01

We tested the hypothesis that melatonin (Mel) enhances exogenous mitochondria (Mito) treatment against rodent hepatic ischemia-reperfusion (IR) injury. In vitro study utilized three groups of hepatocytes (i.e. nontreatment, menadione, and menadione-melatonin treatment, 4.0 × 10(5) each), while in vivo study used adult male Sprague Dawley rats (n = 40) equally divided into sham-control (SC), IR (60-min left-lobe ischemia + 72-hr reperfusion), IR-Mel (melatonin at 30 min/6/8 hr after reperfusion), IR-Mito (mitochondria 15,000 μg/rat 30 min after reperfusion), and IR-Mel-Mito. Following menadione treatment in vitro, oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (cleaved caspase-3/PARP), DNA damage (γ-H2AX/CD90/XRCC1), mitochondria damage (cytosolic cytochrome c) biomarkers, and mitochondrial permeability transition were found to be lower, whereas mitochondrial cytochrome c were found to be higher in hepatocytes with melatonin treatment compared to those without (all P < 0.001). In vivo study demonstrated highest liver injury score and serum AST in IR group, but lowest in SC group and higher in IR-Mito group than that in groups IR-Mel and IR-Mel-Mito, and higher in IR-Mel group than that in IR-Mel-Mito group after 72-hr reperfusion (all P < 0.003). Protein expressions of inflammatory (TNF-α/NF-κB/IL-1β/MMP-9), oxidative stress (NOX-1/NOX-2/oxidized protein), apoptotic (caspase-3/PARP/Bax), and mitochondria damage (cytosolic cytochrome c) biomarkers displayed an identical pattern, whereas mitochondria integrity marker (mitochondrial cytochrome c) showed an opposite pattern compared to that of liver injury score (all P < 0.001) among five groups. Microscopically, expressions of apoptotic nuclei, inflammatory (MPO(+) /CD68(+) /CD14(+) cells), and DNA damage (γ-H2AX(+) cells) biomarkers exhibited an identical pattern compared to that of liver injury score (all P < 0.001) among five groups. Melatonin-supported mitochondria treatment offered an additional benefit of alleviating hepatic IR injury. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A procyanidin type A trimer from cinnamon extract attenuates glial cell swelling and the reduction in glutamate uptake following ischemia-like injury in vitro.

PubMed

Panickar, K S; Polansky, M M; Graves, D J; Urban, J F; Anderson, R A

2012-01-27

Dietary polyphenols exert neuroprotective effects in ischemic injury. The protective effects of a procyanidin type A trimer (trimer 1) isolated from a water soluble cinnamon extract (CE) were investigated on key features of ischemic injury, including cell swelling, increased free radical production, increased intracellular calcium ([Ca(2+)](i)), mitochondrial dysfunction, and the reduction in glutamate uptake. Astrocyte (glial) swelling is a major component of cytotoxic brain edema in ischemia and, along with vasogenic edema, may contribute to increased intracranial pressure, brain herniation, and additional ischemic injuries. C6 glial cultures were exposed to oxygen-glucose deprivation (OGD) for 5 h, and cell swelling was determined at 90 min after the end of OGD. OGD-induced increases in glial swelling were significantly blocked by trimer 1, but not by the major nonpolyphenol fractions of CE including cinnamaldehyde and coumarin. Increased free radical production, a contributing factor in cell swelling following ischemic injury, was also significantly reduced by trimer 1. Mitochondrial dysfunction, another key feature of ischemic injury, is hypothesized to contribute to glial swelling. Depolarization of the inner mitochondrial membrane potential (ΔΨ(m)) was assessed using a fluorescent dye (tetramethylrhodamine ethyl ester [TMRE]), and was significantly attenuated by trimer 1 as was OGD-induced increased [Ca(2+)](i). Taken together with our previous observation that blockers of [Ca(2+)](i) reduce cell swelling, our results indicate that trimer 1 may attenuate cell swelling by regulating [Ca(2+)](i). Trimer 1 also significantly attenuated the OGD-induced decrease in glutamate uptake. In addition, cyclosporin A, a blocker of the mitochondrial permeability pore (mPT), but not FK506 (that does not block the mPT), reduced the OGD-induced decline in glutamate uptake indicating a role of the mPT in such effects. Thus, the effects of trimer 1 in attenuating the reduction in glutamate uptake are likely mediated through their action on the mitochondria. Published by Elsevier Ltd on behalf of IBRO.

PATHOPHYSIOLOGICAL CONSEQUENCES OF TAT-HKII PEPTIDE ADMINISTRATION ARE INDEPENDENT OF IMPAIRED VASCULAR FUNCTION AND ENSUING ISCHEMIA

PubMed Central

Nederlof, Rianne; Xie, Chaoqin; Eerbeek, Otto; Koeman, Anneke; Milstein, Dan MJ; Hollmann, Markus W; Mik, Egbert G; Warley, Alice; Southworth, Richard; Akar, Fadi G.; Zuurbier, Coert J

2013-01-01

Rationale We have shown that partial dissociation of HKII from mitochondria in the intact heart using low dose (200 nM) TAT-HKII prevents the cardioprotective effects of ischemic preconditioning (IPC) whereas high-dose (10 μM) TAT-HKII administration results in rapid myocardial dysfunction, mitochondrial depolarization and disintegration. In this issue of Circulation Research, Pasdois et al argue that the deleterious effects of TAT-HKII administration on cardiac function are likely due to vasoconstriction and ensuing ischemia. Objective To investigate whether altered vascular function and ensuing ischemia recapitulate the deleterious effects of TAT-HKII in intact myocardium. Methods and Results Using a variety of complementary techniques, including mitochondrial membrane potential (ΔΨm) imaging, high-resolution optical action potential (AP) mapping, analysis of lactate production, NADH epifluorescence, lactate dehydrogenase (LDH) release, and electron microscopy, we provide direct evidence that refutes the notion that acute myocardial dysfunction by high-dose TAT-HKII peptide administration is a consequence of impaired vascular function. Moreover, we demonstrate that low-dose TAT-HKII treatment, which abrogates the protective effects of IPC, is not associated with ischemia or ischemic-injury. Conclusions Our findings challenge the notion that the effects of TAT-HKII are attributable to impaired vascular function and ensuing ischemia; thereby, lending further credence to the role of mitochondria bound HKII as a critical regulator of cardiac function, ischemia-reperfusion (IR) injury, and cardioprotection by IPC. PMID:23329797

Involvement of endogenous antioxidant systems in the protective activity of pituitary adenylate cyclase-activating polypeptide against hydrogen peroxide-induced oxidative damages in cultured rat astrocytes.

PubMed

Douiri, Salma; Bahdoudi, Seyma; Hamdi, Yosra; Cubì, Roger; Basille, Magali; Fournier, Alain; Vaudry, Hubert; Tonon, Marie-Christine; Amri, Mohamed; Vaudry, David; Masmoudi-Kouki, Olfa

2016-06-01

Astroglial cells possess an array of cellular defense mechanisms, including superoxide dismutase (SOD) and catalase antioxidant enzymes, to prevent damages caused by oxidative stress. Nevertheless, astroglial cell viability and functionality can be affected by significant oxidative stress. We have previously shown that pituitary adenylate cyclase-activating polypeptide (PACAP) is a potent glioprotective agent that prevents hydrogen peroxide (H2 O2 )-induced apoptosis in cultured astrocytes. The purpose of this study was to investigate the potential protective effect of PACAP against oxidative-generated alteration of astrocytic antioxidant systems. Incubation of cells with subnanomolar concentrations of PACAP inhibited H2 O2 -evoked reactive oxygen species accumulation, mitochondrial respiratory burst, and caspase-3 mRNA level increase. PACAP also stimulated SOD and catalase activities in a concentration-dependent manner, and counteracted the inhibitory effect of H2 O2 on the activity of these two antioxidant enzymes. The protective action of PACAP against H2 O2 -evoked inhibition of antioxidant systems in astrocytes was protein kinase A, PKC, and MAP-kinase dependent. In the presence of H2 O2 , the SOD blocker NaCN and the catalase inhibitor 3-aminotriazole, both suppressed the protective effects of PACAP on SOD and catalase activities, mitochondrial function, and cell survival. Taken together, these results indicate that the anti-apoptotic effect of PACAP on astroglial cells can account for the activation of endogenous antioxidant enzymes and reduction in respiration rate, thus preserving mitochondrial integrity and preventing caspase-3 expression provoked by oxidative stress. Considering its powerful anti-apoptotic and anti-oxidative properties, the PACAPergic signaling system should thus be considered for the development of new therapeutical approaches to cure various pathologies involving oxidative neurodegeneration. We propose the following cascade for the glioprotective action of Pituitary adenylate cyclase-activating polypeptide (PACAP) against H2 O2 -induced astrocyte damages and cell apoptosis in cultured rat astrocytes. PACAP, through activation of its receptor, PAC1-R, and the protein kinase A (PKA), protein kinase C (PKC), and MAP-kinases signaling pathways, prevents accumulation of ROS and inhibition of SOD and catalase activities. This allows the preservation of mitochondrial membrane integrity and the reduction in caspase-3 activation induced by H2 O2 . These data may lead to the development of new strategies for cerebral injury treatment. Cat, catalase; Cyt. C, cytochrome C; SOD, superoxide dismutase. © 2016 International Society for Neurochemistry.

An Overview of Pathways of Regulated Necrosis in Acute Kidney Injury.

PubMed

Kers, Jesper; Leemans, Jaklien C; Linkermann, Andreas

2016-05-01

Necrosis is the predominant form of regulated cell death in acute kidney injury (AKI) and represents results in the formation of casts that appear in the urine sedimentation, referred to as muddy brown casts, which are part of the diagnosis of AKI. Pathologists referred to this typical feature as acute tubular necrosis. We are only beginning to understand the dynamics and the molecular pathways that underlie such typical necrotic morphology. In this review, we provide an overview of candidate pathways and summarize the emerging evidence for the relative contribution of these pathways of regulated necrosis, such as necroptosis, ferroptosis, mitochondrial permeability transition-mediated regulated necrosis, parthanatos, and pyroptosis. Inhibitors of each of these pathways are available, and clinical trials may be started after the detection of the most promising drug targets, which will be discussed here. With the global burden of AKI in mind, inhibitiors of regulated necrosis represent promising means to prevent this disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Blockade of store-operated calcium entry alleviates high glucose-induced neurotoxicity via inhibiting apoptosis in rat neurons.

PubMed

Xu, Zhenkuan; Xu, Wenzhe; Song, Yan; Zhang, Bin; Li, Feng; Liu, Yuguang

2016-07-25

Altered store-operated calcium entry (SOCE) has been suggested to be involved in many diabetic complications. However, the association of altered SOCE and diabetic neuronal damage remains unclear. This study aimed to investigate the effects of altered SOCE on primary cultured rat neuron injury induced by high glucose. Our data demonstrated that high glucose increased rat neuron injury and upregulated the expression of store-operated calcium channel (SOC). Inhibition of SOCE by a pharmacological inhibitor and siRNA knockdown of stromal interaction molecule 1 weakened the intracellular calcium overload, restored mitochondrial membrane potential, downregulated cytochrome C release and inhibited cell apoptosis. As well, treatment with the calcium chelator BAPTA-AM prevented cell apoptosis by ameliorating the high glucose-increased intracellular calcium level. These findings suggest that SOCE blockade may alleviate high glucose-induced neuronal damage by inhibiting apoptosis. SOCE might be a promising therapeutic target in diabetic neurotoxicity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Ionizing radiation accelerates Drp1-dependent mitochondrial fission, which involves delayed mitochondrial reactive oxygen species production in normal human fibroblast-like cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobashigawa, Shinko, E-mail: kobashin@nagasaki-u.ac.jp; Suzuki, Keiji; Yamashita, Shunichi

2011-11-04

Highlights: Black-Right-Pointing-Pointer We report first time that ionizing radiation induces mitochondrial dynamic changes. Black-Right-Pointing-Pointer Radiation-induced mitochondrial fission was caused by Drp1 localization. Black-Right-Pointing-Pointer We found that radiation causes delayed ROS from mitochondria. Black-Right-Pointing-Pointer Down regulation of Drp1 rescued mitochondrial dysfunction after radiation exposure. -- Abstract: Ionizing radiation is known to increase intracellular level of reactive oxygen species (ROS) through mitochondrial dysfunction. Although it has been as a basis of radiation-induced genetic instability, the mechanism involving mitochondrial dysfunction remains unclear. Here we studied the dynamics of mitochondrial structure in normal human fibroblast like cells exposed to ionizing radiation. Delayed mitochondrial O{submore » 2}{sup {center_dot}-} production was peaked 3 days after irradiation, which was coupled with accelerated mitochondrial fission. We found that radiation exposure accumulated dynamin-related protein 1 (Drp1) to mitochondria. Knocking down of Drp1 expression prevented radiation induced acceleration of mitochondrial fission. Furthermore, knockdown of Drp1 significantly suppressed delayed production of mitochondrial O{sub 2}{sup {center_dot}-}. Since the loss of mitochondrial membrane potential, which was induced by radiation was prevented in cells knocking down of Drp1 expression, indicating that the excessive mitochondrial fission was involved in delayed mitochondrial dysfunction after irradiation.« less

Melatonin protect the development of preimplantation mouse embryos from sodium fluoride-induced oxidative injury.

PubMed

Zhao, Jiamin; Fu, Beibei; Peng, Wei; Mao, Tingchao; Wu, Haibo; Zhang, Yong

2017-09-01

Recently study shows that melatonin can protect embryos from the culture environment oxidative stress. However, the protective effect of melatonin on the mouse development of preimplantation embryos under sodium fluoride (NaF) induced oxidative stress is still unclear. Here, we showed that exposure to NaF significantly increased the reactive oxygen species (ROS) level, decreased the blastocyst formation rates, and increased the fragmentation, apoptosis and retardation of blastocysts in the development of mouse preimplantation embryos. However, the protective of melatonin remarkable increased the of blastocyst formation rates, maintained mitochondrial function and total antioxidant capacity by clearing ROS. Importantly the data showed that melatonin improved the activity of enzymatic antioxidants, including glutathione(GSH), superoxide dismutase(SOD), and malonaldehyde (MDA), and increased the expression levels of antioxidative genes. Taken together, our results indicate that melatonin prevent NaF-induced oxidative damage to mouse preimplantation embryo through down regulation of ROS level, stabilization of mitochondrial function and modulation of the activity of antioxidases and antioxidant genes. Copyright © 2017 Elsevier B.V. All rights reserved.

Cardioprotective effect of sulphonated formononetin on acute myocardial infarction in rats.

PubMed

Zhang, Shumin; Tang, Xuexi; Tian, Jingwei; Li, Chunmei; Zhang, Guanbo; Jiang, Wanglin; Zhang, Zunting

2011-06-01

This study was designed to investigate the therapeutic effect of sodium formononetin-3'-sulphonate (Sul-F), a water-soluble derivate of formononetin, on acute myocardial infarction in rats. The results showed that treatment with Sul-F significantly prevented the elevation of ST-segment level, decreased the contents of creatine kinase-MB, lactate dehydrogenase, alanine aminotransferase and cardiac troponin T in serum and reduced the myocardium necrosis scores. The number of apoptosis cardiocytes is well accordance with the up-regulated expression of Bcl-2 and the down-regulated expression of Bax. Meanwhile, Sul-F significantly increased the cardiac mitochondrial ATP content, improved ATP synthase activity, decreased thiobarbituric acid-reactive substances content and attenuated the decrease in superoxide dismutase and glutathione peroxidase activities. These findings indicate that Sul-F has a protective potential against myocardial infarction injury. A possible mechanism for the protective effect is the elevated expression of endogenous antioxidant defence enzymes degraded lipid peroxidation products and improved energy metholism of cardiac mitochondrial, thus attenuating cardiocyte apoptosis. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

Thyroid hormone-induced oxidative stress.

PubMed

Venditti, P; Di Meo, S

2006-02-01

Hypermetabolic state in hyperthyroidism is associated with tissue oxidative injury. Available data indicate that hyperthyroid tissues exhibit an increased ROS and RNS production. The increased mitochondrial ROS generation is a side effect of the enhanced level of electron carriers, by which hyperthyroid tissues increase their metabolic capacity. Investigations of antioxidant defence system have returned controversial results. Moreover, other thyroid hormone-linked biochemical changes increase tissue susceptibility to oxidative challenge, which exacerbates the injury and dysfunction they suffer under stressful conditions. Mitochondria, as a primary target for oxidative stress, might account for hyperthyroidism linked tissue dysfunction. This is consistent with the inverse relationship found between functional recovery of ischemic hyperthyroid hearts and mitochondrial oxidative damage and respiration impairment. However, thyroid hormone-activated mitochondrial mechanisms provide protection against excessive tissue dysfunction, including increased expression of uncoupling proteins, proteolytic enzymes and transcriptional coactivator PGC-1, and stimulate opening of permeability transition pores.

Mitochondrial permeability transition pore inhibitors prevent ethanol-induced neuronal death in mice.

PubMed

Lamarche, Frederic; Carcenac, Carole; Gonthier, Brigitte; Cottet-Rousselle, Cecile; Chauvin, Christiane; Barret, Luc; Leverve, Xavier; Savasta, Marc; Fontaine, Eric

2013-01-18

Ethanol induces brain injury by a mechanism that remains partly unknown. Mitochondria play a key role in cell death processes, notably through the opening of the permeability transition pore (PTP). Here, we tested the effect of ethanol and PTP inhibitors on mitochondrial physiology and cell viability both in vitro and in vivo. Direct addition of ethanol up to 100 mM on isolated mouse brain mitochondria slightly decreased oxygen consumption but did not affect PTP regulation. In comparison, when isolated from ethanol-treated (two doses of 2 g/kg, 2 h apart) 7-day-old mouse pups, brain mitochondria displayed a transient decrease in oxygen consumption but no change in PTP regulation or H2O2 production. Conversely, exposure of primary cultured astrocytes and neurons to 20 mM ethanol for 3 days led to a transient PTP opening in astrocytes without affecting cell viability and to a permanent PTP opening in 10 to 20% neurons with the same percentage of cell death. Ethanol-treated mouse pups displayed a widespread caspase-3 activation in neurons but not in astrocytes and dramatic behavioral alterations. Interestingly, two different PTP inhibitors (namely, cyclosporin A and nortriptyline) prevented both ethanol-induced neuronal death in vivo and ethanol-induced behavioral modifications. We conclude that PTP opening is involved in ethanol-induced neurotoxicity in the mouse.

Melanocortin 4 Receptor Activation Attenuates Mitochondrial Dysfunction in Skeletal Muscle of Diabetic Rats.

PubMed

Zhang, Hao-Hao; Liu, Jiao; Qin, Gui-Jun; Li, Xia-Lian; Du, Pei-Jie; Hao, Xiao; Zhao, Di; Tian, Tian; Wu, Jing; Yun, Meng; Bai, Yan-Hui

2017-11-01

A previous study has confirmed that the central melanocortin system was able to mediate skeletal muscle AMP-activated protein kinase (AMPK) activation in mice fed a high-fat diet, while activation of the AMPK signaling pathway significantly induced mitochondrial biogenesis. Our hypothesis was that melanocortin 4 receptor (MC4R) was involved in the development of skeletal muscle injury in diabetic rats. In this study, we treated diabetic rats intracerebroventricularly with MC4R agonist R027-3225 or antagonist SHU9119, respectively. Then, we measured the production of reactive oxygen species (ROS), the levels of malondialdehyde (MDA) and glutathione (GSH), the mitochondrial DNA (mtDNA) content and mitochondrial biogenesis, and the protein levels of p-AMPK, AMPK, peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), sirtuin 1 (SIRT1), and manganese superoxide dismutase (MnSOD) in the skeletal muscle of diabetic rats. The results showed that there was significant skeletal muscle injury in the diabetic rats along with serious oxidative stress and decreased mitochondrial biogenesis. Treatment with R027-3225 reduced oxidative stress and induced mitochondrial biogenesis in skeletal muscle, and also activated the AMPK-SIRT1-PGC-1α signaling pathway. However, diabetic rats injected with MC4R antagonist SHU9119 showed an aggravated oxidative stress and mitochondrial dysfunction in skeletal muscle. In conclusion, our results revealed that MC4R activation was able to attenuate oxidative stress and mitochondrial dysfunction in skeletal muscle induced by diabetes partially through activating the AMPK-SIRT1-PGC-1α signaling pathway. J. Cell. Biochem. 118: 4072-4079, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

SIRT1 activation by curcumin pretreatment attenuates mitochondrial oxidative damage induced by myocardial ischemia reperfusion injury.

PubMed

Yang, Yang; Duan, Weixun; Lin, Yan; Yi, Wei; Liang, Zhenxing; Yan, Juanjuan; Wang, Ning; Deng, Chao; Zhang, Song; Li, Yue; Chen, Wensheng; Yu, Shiqiang; Yi, Dinghua; Jin, Zhenxiao

2013-12-01

Ischemia reperfusion (IR) injury (IRI) is harmful to the cardiovascular system and causes mitochondrial oxidative stress. Silent information regulator 1 (SIRT1), a type of histone deacetylase, contributes to IRI. Curcumin (Cur) is a strong natural antioxidant and is the active component in Curcuma longa; Cur has protective effects against IRI and may regulate the activity of SIRT1. This study was designed to investigate the protective effect of Cur pretreatment on myocardial IRI and to elucidate this potential mechanism. Isolated and in vivo rat hearts and cultured neonatal rat cardiomyocytes were subjected to IR. Prior to this procedure, the hearts or cardiomyocytes were exposed to Cur in the absence or presence of the SIRT1 inhibitor sirtinol or SIRT1 siRNA. Cur conferred a cardioprotective effect, as shown by improved postischemic cardiac function, decreased myocardial infarct size, decreased myocardial apoptotic index, and several biochemical parameters, including the up-regulation of the antiapoptotic protein Bcl2 and the down-regulation of the proapoptotic protein Bax. Sirtinol and SIRT1 siRNA each blocked the Cur-mediated cardioprotection by inhibiting SIRT1 signaling. Cur also resulted in a well-preserved mitochondrial redox potential, significantly elevated mitochondrial superoxide dismutase activity, and decreased formation of mitochondrial hydrogen peroxide and malondialdehyde. These observations indicated that the IR-induced mitochondrial oxidative damage was remarkably attenuated. However, this Cur-elevated mitochondrial function was reversed by sirtinol or SIRT1 siRNA treatment. In summary, our results demonstrate that Cur pretreatment attenuates IRI by reducing IR-induced mitochondrial oxidative damage through the activation of SIRT1 signaling. © 2013 Elsevier Inc. All rights reserved.

PPAR agonists as therapeutics for CNS trauma and neurological diseases

PubMed Central

Mandrekar-Colucci, Shweta; Sauerbeck, Andrew; Popovich, Phillip G.; McTigue, Dana M.

2013-01-01

Traumatic injury or disease of the spinal cord and brain elicits multiple cellular and biochemical reactions that together cause or are associated with neuropathology. Specifically, injury or disease elicits acute infiltration and activation of immune cells, death of neurons and glia, mitochondrial dysfunction, and the secretion of substrates that inhibit axon regeneration. In some diseases, inflammation is chronic or non-resolving. Ligands that target PPARs (peroxisome proliferator-activated receptors), a group of ligand-activated transcription factors, are promising therapeutics for neurologic disease and CNS injury because their activation affects many, if not all, of these interrelated pathologic mechanisms. PPAR activation can simultaneously weaken or reprogram the immune response, stimulate metabolic and mitochondrial function, promote axon growth and induce progenitor cells to differentiate into myelinating oligodendrocytes. PPAR activation has beneficial effects in many pre-clinical models of neurodegenerative diseases and CNS injury; however, the mechanisms through which PPARs exert these effects have yet to be fully elucidated. In this review we discuss current literature supporting the role of PPAR activation as a therapeutic target for treating traumatic injury and degenerative diseases of the CNS. PMID:24215544

Oxidative muscular injury and its relevance to hyperthyroidism.

PubMed

Asayama, K; Kato, K

1990-01-01

In experimental hyperthyroidism, acceleration of lipid peroxidation occurs in heart and slow-oxidative muscles, suggesting the contribution of reactive oxygen species to the muscular injury caused by thyroid hormones. This article reviews various models of oxidative muscular injury and considers the relevance of the accompanying metabolic derangements to thyrotoxic myopathy and cardiomyopathy, which are the major complications of hyperthyroidism. The muscular injury models in which reactive oxygen species are supposed to play a role are ischemia/reperfusion syndrome, exercise-induced myopathy, heart and skeletal muscle diseases related to the nutritional deficiency of selenium and vitamin E and related disorders, and genetic muscular dystrophies. These models provide evidence that mitochondrial function and the glutathione-dependent antioxidant system are important for the maintenance of the structural and functional integrity of muscular tissues. Thyroid hormones have a profound effect on mitochondrial oxidative activity, synthesis and degradation of proteins and vitamin E, the sensitivity of the tissues to catecholamine, the differentiation of muscle fibers, and the levels of antioxidant enzymes. The large volume of circumstantial evidence presented here indicates that hyperthyroid muscular tissues undergo several biochemical changes that predispose them to free radical-mediated injury.

Vildagliptin reduces cardiac ischemic-reperfusion injury in obese orchiectomized rats.

PubMed

Pongkan, Wanpitak; Pintana, Hiranya; Jaiwongkam, Thidarat; Kredphoo, Sasiwan; Sivasinprasasn, Sivaporn; Chattipakorn, Siriporn C; Chattipakorn, Nipon

2016-10-01

Obesity and testosterone deprivation are associated with coronary artery disease. Testosterone and vildagliptin (dipeptidyl peptidase-4 inhibitors) exert cardioprotection during ischemic-reperfusion (I/R) injury. However, the effect of these drugs on I/R heart in a testosterone-deprived, obese, insulin-resistant model is unclear. This study investigated the effects of testosterone and vildagliptin on cardiac function, arrhythmias and the infarct size in I/R heart of testosterone-deprived rats with obese insulin resistance. Orchiectomized (O) or sham operated (S) male Wistar rats were divided into 2 groups to receive normal diet (ND) or high-fat diet (HFD) for 12 weeks. Orchiectomized rats in each diet were divided to receive testosterone (2 mg/kg), vildagliptin (3 mg/kg) or the vehicle daily for 4 weeks. Then, I/R was performed by a 30-min left anterior descending coronary artery ligation, followed by a 120-min reperfusion. LV function, arrhythmia scores, infarct size and cardiac mitochondrial function were determined. HFD groups developed insulin resistance at week 12. At week 16, cardiac function was impaired in NDO, HFO and HFS rats, but was restored in all testosterone- and vildagliptin-treated rats. During I/R injury, arrhythmia scores, infarct size and cardiac mitochondrial dysfunction were prominently increased in NDO, HFO and HFS rats, compared with those in NDS rats. Treatment with either testosterone or vildagliptin similarly attenuated these impairments during I/R injury. These finding suggest that both testosterone replacement and vildagliptin share similar efficacy for cardioprotection during I/R injury by decreasing the infarct size and attenuating cardiac mitochondrial dysfunction caused by I/R injury in testosterone-deprived rats with obese insulin resistance. © 2016 Society for Endocrinology.

Avocado Oil Improves Mitochondrial Function and Decreases Oxidative Stress in Brain of Diabetic Rats.

PubMed

Ortiz-Avila, Omar; Esquivel-Martínez, Mauricio; Olmos-Orizaba, Berenice Eridani; Saavedra-Molina, Alfredo; Rodriguez-Orozco, Alain R; Cortés-Rojo, Christian

2015-01-01

Diabetic encephalopathy is a diabetic complication related to the metabolic alterations featuring diabetes. Diabetes is characterized by increased lipid peroxidation, altered glutathione redox status, exacerbated levels of ROS, and mitochondrial dysfunction. Although the pathophysiology of diabetic encephalopathy remains to be clarified, oxidative stress and mitochondrial dysfunction play a crucial role in the pathogenesis of chronic diabetic complications. Taking this into consideration, the aim of this work was to evaluate the effects of 90-day avocado oil intake in brain mitochondrial function and oxidative status in streptozotocin-induced diabetic rats (STZ rats). Avocado oil improves brain mitochondrial function in diabetic rats preventing impairment of mitochondrial respiration and mitochondrial membrane potential (ΔΨ m ), besides increasing complex III activity. Avocado oil also decreased ROS levels and lipid peroxidation and improved the GSH/GSSG ratio as well. These results demonstrate that avocado oil supplementation prevents brain mitochondrial dysfunction induced by diabetes in association with decreased oxidative stress.

Albumin Overload and PINK1/Parkin Signaling-Related Mitophagy in Renal Tubular Epithelial Cells.

PubMed

Tan, Jin; Xie, Qi; Song, Shuling; Miao, Yuyang; Zhang, Qiang

2018-03-01

BACKGROUND Albumin, as a major urinary protein component, is a risk factor for chronic kidney disease progression. Mitochondrial dysfunction is one of the main causes of albumin-induced proximal tubule cells injury. Mitophagy is considered as a pivotal protective mechanism for the elimination of dysfunctional mitochondria. The objective of this research was to determine whether albumin overload-induced mitochondrial dysfunction can activate PINK1/Parkin-mediated mitophagy in renal tubular epithelial cells (TECs). MATERIAL AND METHODS Immunofluorescence assay and Western blot assay were used to detect the effects of albumin overload on autophagy marker protein LC3. Transmission electron microscopy and Western blot assay were used to investigate the role of albumin in mitochondrial injury. Western blot assay and co-localization of acidic lysosomes and mitochondria assay were employed to detect the activation of mitophagy induced by albumin. Finally, we explored the role of PINK1/Parkin signaling in albumin-induced mitophagy by inhibiting mitophagy by knockdown of PARK2 (Parkin) level. RESULTS Immunofluorescence and Western blot results showed that the expression level of LC3-II increased, and the maximum increase point was observed after 8 h of albumin treatment. Transmission electron microscopy results demonstrated that albumin overload-induced mitochondrial injury and quantity of autophagosomes increased. Additionally, expression of PINK1 and cytosolic cytochrome C increased and mitochondria cytochrome C decreased in the albumin group. The co-localization of acidic lysosomes and mitochondria demonstrated that the number of albumin overload-induced mitophagy-positive dots increased. The transient transfection of PARK2 siRNA result showed knockdown of the expression level of PARK2 can inhibit mitophagy induced by albumin. CONCLUSIONS In conclusion, our study suggests that mitochondrial dysfunction activates the PINK1/Parkin signaling and mitophagy in renal tubular epithelial cells under albumin overload condition.

Cinnamon polyphenols attenuate cell swelling and mitochondrial dysfunction following oxygen-glucose deprivation in glial cells.

PubMed

Panickar, Kiran S; Polansky, Marilyn M; Anderson, Richard A

2009-04-01

Astrocyte swelling is an integral component of cytotoxic brain edema in ischemic injury. While mechanisms underlying astrocyte swelling are likely multifactorial, oxidative stress and mitochondrial dysfunction are hypothesized to contribute to such swelling. We investigated the protective effects of cinnamon polyphenol extract (CPE) that has anti-oxidant and insulin-potentiating effects on cell swelling and depolarization of the inner mitochondrial membrane potential (DeltaPsi(m)) in ischemic injury. C6 glial cells were subjected to oxygen-glucose deprivation (OGD) and cell volume determined using the 3-O-methyl-[3H]-glucose method at 90 min after the end of OGD. When compared with controls, OGD increased cell volume by 34%. This increase was blocked by CPE or insulin but not by blockers of oxidative/nitrosative stress including vitamin E, resveratrol, N-nitro-L-arginine methyl ester (L-NAME) or uric acid. Mitochondrial dysfunction, a key component of ischemic injury, contributes to cell swelling. Changes in DeltaPsi(m) were assessed at the end of OGD with tetramethylrhodamine ethyl ester (TMRE), a potentiometric dye. OGD induced a 39% decline in DeltaPsi(m) and this decline was blocked by CPE as well as insulin. To test the involvement of the mitochondrial permeability transition (mPT), we used Cyclosporin A (CsA), an immunosuppressant and a blocker of the mPT pore. CsA blocked cell swelling and the decline in DeltaPsi(m) but FK506, an immunosuppressant that does not block the mPT, did not. Our results show that CPE reduces OGD-induced cell swelling as well as the decline in DeltaPsi(m) in cultures and some of its protective effects may be through inhibiting the mPT.

6-HYDROXYDOPAMINE INDUCES MITOCHONDRIAL ERK ACTIVATION

PubMed Central

Kulich, Scott M.; Horbinski, Craig; Patel, Manisha; Chu, Charleen T.

2007-01-01

Reactive oxygen species (ROS) are implicated in 6-hydroxydopamine (6-OHDA) injury to catecholaminergic neurons; however, the mechanism(s) are unclear. In addition to ROS generated during autoxidation, 6-OHDA may initiate secondary cellular sources of ROS that contribute to toxicity. Using a neuronal cell line, we found that catalytic metalloporphyrin antioxidants conferred protection if added 1 hour after exposure to 6-OHDA, whereas the hydrogen peroxide scavenger catalase failed to protect if added more than 15 min after 6-OHDA. There was a temporal correspondence between loss of protection and loss of the ability of the antioxidant to inhibit 6-OHDA-induced ERK phosphorylation. Time course studies of aconitase inactivation, as an indicator of intracellular superoxide, and MitoSOX red, a mitochondria targeted ROS indicator, demonstrate early intracellular ROS followed by a delayed phase of mitochondrial ROS production, associated with phosphorylation of a mitochondrial pool of ERK. Furthermore, upon initiation of mitochondrial ROS and ERK activation, 6-OHDA-injured cells became refractory to rescue by metalloporphyrin antioxidants. Together with previous studies showing that inhibition of the ERK pathway confers protection from 6-OHDA toxicity, and that phosphorylated ERK accumulates in mitochondria of degenerating human Parkinson’s disease neurons, these studies implicate mitochondrial ERK activation in Parkinsonian oxidative neuronal injury. PMID:17602953

Cisplatin impairs rat liver mitochondrial functions by inducing changes on membrane ion permeability: prevention by thiol group protecting agents.

PubMed

Custódio, José B A; Cardoso, Carla M P; Santos, Maria S; Almeida, Leonor M; Vicente, Joaquim A F; Fernandes, Maria A S

2009-05-02

Cisplatin (CisPt) is the most important platinum anticancer drug widely used in the treatment of head, neck, ovarian and testicular cancers. However, the mechanisms by which CisPt induces cytotoxicity, namely hepatotoxicity, are not completely understood. The goal of this study was to investigate the influence of CisPt on rat liver mitochondrial functions (Ca(2+)-induced mitochondrial permeability transition (MPT), mitochondrial bioenergetics, and mitochondrial oxidative stress) to better understand the mechanism underlying its hepatotoxicity. The effect of thiol group protecting agents and some antioxidants against CisPt-induced mitochondrial damage was also investigated. Treatment of rat liver mitochondria with CisPt (20nmol/mg protein) induced Ca(2+)-dependent mitochondrial swelling, depolarization of membrane potential (DeltaPsi), Ca(2+) release, and NAD(P)H fluorescence intensity decay. These effects were prevented by cyclosporine A (CyA), a potent and specific inhibitor of the MPT. In the concentration range of up to 40nmol/mg protein, CisPt slightly inhibited state 3 and stimulated state 2 and state 4 respiration rates using succinate as respiratory substrate. The respiratory indexes, respiratory control ratio (RCR) and ADP/O ratios, the DeltaPsi, and the ADP phosphorylation rate were also depressed. CisPt induced mitochondrial inner membrane permeabilization to protons (proton leak) but did not induce significant changes on mitochondrial H(2)O(2) generation. All the effects induced by CisPt on rat liver mitochondria were prevented by thiol group protecting agents namely, glutathione (GSH), dithiothreitol (DTT), N-acetyl-L-cysteine (NAC) and cysteine (CYS), whereas superoxide-dismutase (SOD), catalase (CAT) and ascorbate (ASC) were without effect. In conclusion, the anticancer drug CisPt: (1) increases the sensitivity of mitochondria to Ca(2+)-induced MPT; (2) interferes with mitochondrial bioenergetics by increasing mitochondrial inner membrane permeabilization to H(+); (3) does not significantly affect H(2)O(2) generation by mitochondria; (4) its mitochondrial damaging effects are protected by thiol group protecting agents. Based on these conclusions, it is possible to hypothesise that small changes on the redox-status of thiol groups, affecting membrane permeability to cations (Ca(2+) and H(+)) underlie CisPt-induced liver mitochondrial damage, putatively responsible for its hepatotoxicity. Therefore, we propose that CisPt-induced mitochondrial damage and consequent hepatotoxicity could be prevented by using thiol group protecting agents as therapeutic adjuvants.

Study the oxidative injury of yeast cells by NADH autofluorescence

NASA Astrophysics Data System (ADS)

Liang, Ju; Wu, Wen-Lan; Liu, Zhi-Hong; Mei, Yun-Jun; Cai, Ru-Xiu; Shen, Ping

2007-06-01

Autofluorescence has an advantage over the extrinsic fluorescence of an unperturbed environment during investigation, especially in complex system such as biological cells and tissues. NADH is an important fluorescent substance in living cells. The time courses of intracellular NADH autofluorescence in the process of yeast cells exposed to H 2O 2 and ONOO - have been recorded in detail in this work. In the presence of different amounts of H 2O 2 and ONOO -, necrosis, apoptosis and reversible injury are initiated in yeast cells, which are confirmed by acridine orange/ethidum bromide and Annexin V/propidium iodide staining. It is found that intracellular NADH content increases momently in the beginning of the apoptotic process and then decreases continually till the cell dies. The most remarkable difference between the apoptotic and the necrotic process is that the NADH content in the latter case changes much more sharply. Further in the case of reversible injury, the time course of intracellular NADH content is completely different from the above two pathways of cell death. It just decreases to some degree firstly and then resumes to the original level. Based on the role of NADH in mitochondrial respiratory chain, the time course of intracellular NADH content is believed to have reflected the response of mitochondrial redox state to oxidative stress. Thus, it is found that the mitochondrial redox state changes differently in different pathways of oxidative injury in yeast cells.

Synergistic effects of hydrogen peroxide and ethanol on cell viability loss in PC12 cells by increase in mitochondrial permeability transition.

PubMed

Lee, Chung Soo; Kim, Yun Jeong; Ko, Hyun Hee; Han, Eun Sook

2005-07-15

The promoting effect of ethanol against the cytotoxicity of hydrogen peroxide (H2O2) in differentiated PC12 cells was assessed by measuring the effect on the mitochondrial membrane permeability. Treatment of PC12 cells with H2O2 resulted in the nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species (ROS) and depletion of GSH. In PC12 cells and dopaminergic neuroblastoma SH-SY5Y cells, the promoting effect of ethanol on the H2O2-induced cell death was increased with exposure time. Ethanol promoted the nuclear damage, change in the mitochondrial membrane permeability, ROS formation and decrease in GSH contents due to H2O2 in PC12 cells. Catalase, carboxy-PTIO, Mn-TBAP, N-acetylcysteine, cyclosporin A and trifluoperazine inhibited the H2O2 and ethanol-induced mitochondrial dysfunction and cell injury. The results show that the ethanol treatment promotes the cytotoxicity of H2O2 against PC12 cells. Ethanol may enhance the H2O2-induced viability loss in PC12 cells by promoting the mitochondrial membrane permeability change, release of cytochrome c and subsequent activation of caspase-3, which is associated with the increased formation of ROS and depletion of GSH. The findings suggest that ethanol as a promoting agent for the formation of mitochondrial permeability transition may enhance the neuronal cell injury caused by oxidants.

Mitochondrial aquaporin-8 knockdown in human hepatoma HepG2 cells causes ROS-induced mitochondrial depolarization and loss of viability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchissio, Maria Julia; Francés, Daniel Eleazar Antonio; Carnovale, Cristina Ester

Human aquaporin-8 (AQP8) channels facilitate the diffusional transport of H{sub 2}O{sub 2} across membranes. Since AQP8 is expressed in hepatic inner mitochondrial membranes, we studied whether mitochondrial AQP8 (mtAQP8) knockdown in human hepatoma HepG2 cells impairs mitochondrial H{sub 2}O{sub 2} release, which may lead to organelle dysfunction and cell death. We confirmed AQP8 expression in HepG2 inner mitochondrial membranes and found that 72 h after cell transfection with siRNAs targeting two different regions of the human AQP8 molecule, mtAQP8 protein specifically decreased by around 60% (p < 0.05). Studies in isolated mtAQP8-knockdown mitochondria showed that H{sub 2}O{sub 2} release, assessedmore » by Amplex Red, was reduced by about 45% (p < 0.05), an effect not observed in digitonin-permeabilized mitochondria. mtAQP8-knockdown cells showed an increase in mitochondrial ROS, assessed by dichlorodihydrofluorescein diacetate (+ 120%, p < 0.05) and loss of mitochondrial membrane potential (− 80%, p < 0.05), assessed by tetramethylrhodamine-coupled quantitative fluorescence microscopy. The mitochondria-targeted antioxidant MitoTempol prevented ROS accumulation and dissipation of mitochondrial membrane potential. Cyclosporin A, a mitochondrial permeability transition pore blocker, also abolished the mtAQP8 knockdown-induced mitochondrial depolarization. Besides, the loss of viability in mtAQP8 knockdown cells verified by MTT assay, LDH leakage, and trypan blue exclusion test could be prevented by cyclosporin A. Our data on human hepatoma HepG2 cells suggest that mtAQP8 facilitates mitochondrial H{sub 2}O{sub 2} release and that its defective expression causes ROS-induced mitochondrial depolarization via the mitochondrial permeability transition mechanism, and cell death. -- Highlights: ► Aquaporin-8 is expressed in mitochondria of human hepatoma HepG2 cells. ► Aquaporin-8 knockdown impairs mitochondrial H{sub 2}O{sub 2} release and increases ROS. ► Aquaporin-8 knockdown causes ROS-induced mitochondrial depolarization and cell death. ► Mitochondrial permeability transition blockage prevents depolarization and cell death.« less

Endurance exercise rescues progeroid aging and induces systemic mitochondrial rejuvenation in mtDNA mutator mice

PubMed Central

Safdar, Adeel; Bourgeois, Jacqueline M.; Ogborn, Daniel I.; Little, Jonathan P.; Hettinga, Bart P.; Akhtar, Mahmood; Thompson, James E.; Melov, Simon; Mocellin, Nicholas J.; Kujoth, Gregory C.; Prolla, Tomas A.; Tarnopolsky, Mark A.

2011-01-01

A causal role for mitochondrial DNA (mtDNA) mutagenesis in mammalian aging is supported by recent studies demonstrating that the mtDNA mutator mouse, harboring a defect in the proofreading-exonuclease activity of mitochondrial polymerase gamma, exhibits accelerated aging phenotypes characteristic of human aging, systemic mitochondrial dysfunction, multisystem pathology, and reduced lifespan. Epidemiologic studies in humans have demonstrated that endurance training reduces the risk of chronic diseases and extends life expectancy. Whether endurance exercise can attenuate the cumulative systemic decline observed in aging remains elusive. Here we show that 5 mo of endurance exercise induced systemic mitochondrial biogenesis, prevented mtDNA depletion and mutations, increased mitochondrial oxidative capacity and respiratory chain assembly, restored mitochondrial morphology, and blunted pathological levels of apoptosis in multiple tissues of mtDNA mutator mice. These adaptations conferred complete phenotypic protection, reduced multisystem pathology, and prevented premature mortality in these mice. The systemic mitochondrial rejuvenation through endurance exercise promises to be an effective therapeutic approach to mitigating mitochondrial dysfunction in aging and related comorbidities. PMID:21368114

Structural and functional alterations in rhodamine-123- and doxycycline-photosensitized cells

NASA Astrophysics Data System (ADS)

Shea, Christopher R.; Whitaker, Diana; Murphy, George F.; Chen, Norah; Wimberly, Joanne; Scholz, M.; Sherwood, M. E.; Flotte, Thomas J.; Hasan, Tayyaba

1990-06-01

In order to elucidate the mechanisms of photosensitized injury to mitochondria, two photosensitizers have been compared. Both doxycycline (DOTC) and rhodamine-l23 (R123) localize preferentially within the mitochondria of MGH-IJ1 bladder carcinoma cells j1 vitro, and both sensitize phototoxic injury that is selective for mitochondria. Mitochondria of cells pretreated with DOTC and irradiated with UVA (1 J/cm2, 320-400 rim) undergo massive swelling that begins by 10 mm after irradiation, is maximal by 1 h, and is partially repaired by 4 h; damage caused by exposure to a higher UVA dose (6 J/cm2), however, is not repaired. In contrast, cells pretreated with R123 and irradiated with an argon-ion laser (10 J/cm2, 514.5 rim) undergo a different type of mitochondrial injury, characterized by the delayed (4 h) onset of moderate mitochondrial swelling and striking mitochondrial distortion and fragmentation, which is not repaired by 48 h after irradiation. These differences indicate that the reactions underlying cellular phototoxicity can be distinguished even on an ultrastructural level. Probably both the primary photochemistry and the submitochondrial targets of these reactions differ with the two photosensitizers.

The muscle-specific ubiquitin ligase atrogin-1/MAFbx mediates statin-induced muscle toxicity

PubMed Central

Hanai, Jun-ichi; Cao, Peirang; Tanksale, Preeti; Imamura, Shintaro; Koshimizu, Eriko; Zhao, Jinghui; Kishi, Shuji; Yamashita, Michiaki; Phillips, Paul S.; Sukhatme, Vikas P.; Lecker, Stewart H.

2007-01-01

Statins inhibit HMG-CoA reductase, a key enzyme in cholesterol synthesis, and are widely used to treat hypercholesterolemia. These drugs can lead to a number of side effects in muscle, including muscle fiber breakdown; however, the mechanisms of muscle injury by statins are poorly understood. We report that lovastatin induced the expression of atrogin-1, a key gene involved in skeletal muscle atrophy, in humans with statin myopathy, in zebrafish embryos, and in vitro in murine skeletal muscle cells. In cultured mouse myotubes, atrogin-1 induction following lovastatin treatment was accompanied by distinct morphological changes, largely absent in atrogin-1 null cells. In zebrafish embryos, lovastatin promoted muscle fiber damage, an effect that was closely mimicked by knockdown of zebrafish HMG-CoA reductase. Moreover, atrogin-1 knockdown in zebrafish embryos prevented lovastatin-induced muscle injury. Finally, overexpression of PGC-1α, a transcriptional coactivator that induces mitochondrial biogenesis and protects against the development of muscle atrophy, dramatically prevented lovastatin-induced muscle damage and abrogated atrogin-1 induction both in fish and in cultured mouse myotubes. Collectively, our human, animal, and in vitro findings shed light on the molecular mechanism of statin-induced myopathy and suggest that atrogin-1 may be a critical mediator of the muscle damage induced by statins. PMID:17992259

Mangiferin Enhanced Autophagy via Inhibiting mTORC1 Pathway to Prevent High Glucose-Induced Cardiomyocyte Injury.

PubMed

Hou, Jun; Zheng, Dezhi; Xiao, Wenjing; Li, Dandan; Ma, Jie; Hu, Yonghe

2018-01-01

Mangiferin functions as a perfect anti-oxidative compound in the diabetic heart, however, the exact mechanism remains to be elucidated. Here, we show the cardioprotective effect of mangiferin under high glucose-induced cardiotoxic condition mainly contributed to enhanced autophagy via suppressing mTORC1 downstream signal transduction. Primary neonatal rat cardiomyocytes were cultured to detect myocytes injury, autophagy, and related signal transduction under different doses of glucose and mangiferin treatment. High glucose (30 mM) reduced autophagic flux, and increased myocyte apoptosis and death compared with normal glucose (5.5 mM) as determined by variation of autophagy markers LC3-II, p62, parkin, GFP-LC3, or mRFP-LC3 fluorescence puncta, cell viability, cleaved caspase 3, cleaved PARP apoptosis indices, reactive oxygen species (ROS), MAO, and PI death indices. Conversely, mangiferin inhibited hyperglycemia associated oxidative stress by reducing ROS, MAO, cleaved caspase 3, and cleaved PARP generation, reestablishing cell viability, mitochondrial membrane potential, and enhancing autophagic flux, thereby preventing myocytes from high glucose-induced toxicity. Furthermore, cardioprotection with mangiferin was potentially related to the decreased mTOR phosphorylation and suppression of mTORC1 downstream signaling pathway. These data indicated the valuable effects of mangiferin on regulation of cardiac autophagy and pointed to the promising utilization for hyperglycemia control.

Inhibition of mitochondrial fission prevents hypoxia-induced metabolic shift and cellular proliferation of pulmonary arterial smooth muscle cells.

PubMed

Parra, Valentina; Bravo-Sagua, Roberto; Norambuena-Soto, Ignacio; Hernández-Fuentes, Carolina P; Gómez-Contreras, Andrés G; Verdejo, Hugo E; Mellado, Rosemarie; Chiong, Mario; Lavandero, Sergio; Castro, Pablo F

2017-11-01

Chronic hypoxia exacerbates proliferation of pulmonary arterial smooth muscle cells (PASMC), thereby reducing the lumen of pulmonary arteries. This leads to poor blood oxygenation and cardiac work overload, which are the basis of diseases such as pulmonary artery hypertension (PAH). Recent studies revealed an emerging role of mitochondria in PAH pathogenesis, as key regulators of cell survival and metabolism. In this work, we assessed whether hypoxia-induced mitochondrial fragmentation contributes to the alterations of both PASMC death and proliferation. In previous work in cardiac myocytes, we showed that trimetazidine (TMZ), a partial inhibitor of lipid oxidation, stimulates mitochondrial fusion and preserves mitochondrial function. Thus, here we evaluated whether TMZ-induced mitochondrial fusion can prevent human PASMC proliferation in an in vitro hypoxic model. Using confocal fluorescence microscopy, we showed that prolonged hypoxia (48h) induces mitochondrial fragmentation along with higher levels of the mitochondrial fission protein DRP1. Concomitantly, both mitochondrial potential and respiratory rates decreased, indicative of mitochondrial dysfunction. In accordance with a metabolic shift towards non-mitochondrial ATP generation, mRNA levels of glycolytic markers HK2, PFKFB2 and GLUT1 increased during hypoxia. Incubation of PASMC with TMZ, prior to hypoxia, prevented all these changes and precluded the increase in PASMC proliferation. These findings were also observed using Mdivi-1 (a pharmacological DRP1 inhibitor) or a dominant negative DRP1 K38A as pre-treatments. Altogether, our data indicate that TMZ exerts a protective role against hypoxia-induced PASMC proliferation, by preserving mitochondrial function, thus highlighting DRP1-dependent morphology as a novel therapeutic approach for diseases such as PAH. Copyright © 2017 Elsevier B.V. All rights reserved.

Protective properties of sesamin against fluoride-induced oxidative stress and apoptosis in kidney of carp (Cyprinus carpio) via JNK signaling pathway.

PubMed

Cao, Jinling; Chen, Jianjie; Xie, Lingtian; Wang, Jundong; Feng, Cuiping; Song, Jing

2015-10-01

Sesamin, a major lignan derived from sesame seeds, has been reported to have many benefits and medicinal properties. However, its protective effects against fluoride-induced injury in kidney of fish have not been clarified. Previously we found that fluoride exposure caused damage and apoptosis in the kidneys of the common carp, Cyprinus carpio. In this study, the effects of sesamin on renal oxidative stress and apoptosis in fluoride-exposed fish were determined. The results showed that sesamin alleviated significantly fluoride-induced renal damage and apoptosis of carp in a dose-dependent manner, indicated by the histopathological examination and ultrastructural observation. Moreover, treatment with sesamin also inhibited significantly fluoride-induced remarkable enhancement of reactive oxygen species (ROS) production and oxidative stress, such as the increase of lipid peroxidation level and the depletion of intracellular reduced glutathione (GSH) level in kidney. To explore the underlying mechanisms of sesamin action, we found that activities of caspase-3 were notably inhibited by treatment with sesamin in the kidney of fluoride-exposed fish. Sesamin decreased the levels of p-JNK protein in kidney, which in turn inactivated pro-apoptotic signaling events by restoring the balance between mitochondrial pro- and anti-apoptotic Bcl-2 and Bax proteins and by decreasing the release of mitochondrial cytochrome c in kidney of fluoride-exposed fish. JNK was also involved in the mitochondrial extrinsic apoptotic pathways of sesamin effects against fluoride-induced renal injury by regulating the levels of p-c-Jun, necrosis factor-alpha (TNF-α) and Bak proteins. These findings indicated that sesamin could protect kidney against fluoride-induced apoptosis by the oxidative stress downstream-mediated change in the inactivation of JNK signaling pathway. Taken together, sesamin plays an important role in maintaining renal health and preventing kidney from toxic damage induced by fluoride. Copyright © 2015 Elsevier B.V. All rights reserved.

[Protective effect of hydrogen against hyperoxia-induced type II alveolar epithelial cell injury].

PubMed

Yao, Lan; Xu, Feng; Luo, Chong; Yu, Pan; Dong, Xinxin; Sun, Xuejun; Liu, Chengjun

2013-02-01

To investigate the protective effect of hydrogen against hyperoxia-induced oxidative stress injury in premature rat type II alveolar epithelial cells (AECs). The type II AECs isolated from premature rats were randomly divided into air (21% oxygen) control group, hyperoxia (95% oxygen) control group, air + hydrogen group, and hyperoxia+ hydrogen group. The cells with hydrogen treatment were cultured in the presence of rich hydrogen. After the corresponding exposure for 24 h, the cell morphology was observed microscopically. MTT assay was used to evaluated the cell proliferation ability, and JC-1 fluorescence probe was used to detect the mitochondrial membrane potential (δφ) changes of the type II AECs. The concentration of maleic dialdehyde (MDA) and superoxide dismutase (SOD) activity in the cell supernatant were detected using colorimetric method. No significant differences were found in cell growth or measurements between air control and air + hydrogen groups. Compared with air control group, the cells exposed to hyperoxia showed significantly suppressed proliferation, reduced mitochondrial membrane potential, increased MDA content, and decreased SOD activity. Intervention with hydrogen resulted in significantly increased cell proliferation and SOD activity and lowered MDA content, and restored the mitochondrial membrane potential in the cells with hyperoxia exposure (P<0.05). Hydrogen can significantly reduce hyperoxia-induced oxidative stress injury in premature rat type II AECs, improve the cellular antioxidant capacity, stabilize the mitochondrial membrane potential, and reduce the inhibitory effect of hyperoxia on cell proliferation.

α7 Nicotinic Acetylcholine Receptor Signaling Inhibits Inflammasome Activation by Preventing Mitochondrial DNA Release

PubMed Central

Lu, Ben; Kwan, Kevin; Levine, Yaakov A; Olofsson, Peder S; Yang, Huan; Li, Jianhua; Joshi, Sonia; Wang, Haichao; Andersson, Ulf; Chavan, Sangeeta S; Tracey, Kevin J

2014-01-01

The mammalian immune system and the nervous system coevolved under the influence of cellular and environmental stress. Cellular stress is associated with changes in immunity and activation of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome, a key component of innate immunity. Here we show that α7 nicotinic acetylcholine receptor (α7 nAchR)-signaling inhibits inflammasome activation and prevents release of mitochondrial DNA, an NLRP3 ligand. Cholinergic receptor agonists or vagus nerve stimulation significantly inhibits inflammasome activation, whereas genetic deletion of α7 nAchR significantly enhances inflammasome activation. Acetylcholine accumulates in macrophage cytoplasm after adenosine triphosphate (ATP) stimulation in an α7 nAchR-independent manner. Acetylcholine significantly attenuated calcium or hydrogen oxide–induced mitochondrial damage and mitochondrial DNA release. Together, these findings reveal a novel neurotransmitter-mediated signaling pathway: acetylcholine translocates into the cytoplasm of immune cells during inflammation and inhibits NLRP3 inflammasome activation by preventing mitochondrial DNA release. PMID:24849809

Silencing of p53 RNA through transarterial delivery ameliorates renal tubular injury and downregulates GSK-3β expression after ischemia-reperfusion injury.

PubMed

Fujino, Takayuki; Muhib, Sharifi; Sato, Nobuyuki; Hasebe, Naoyuki

2013-12-01

p53, a pivotal protein in the apoptotic pathway, has been identified as a mediator of transcriptional responses to ischemia-reperfusion (IR) injury. The characteristics and functional significance of the p53 response in vivo are largely unknown in IR-induced kidney injury. Therapeutic opportunities of delivering small interfering RNA (siRNA) via venous injection have gained recognition; however, systemic adverse effects of siRNA therapy should be considered. To prevent IR-induced kidney injury, we tested the efficacy of transarterial administration of siRNA targeting p53 (p53 siRNA). Female C57BL/6 mice underwent unilateral renal artery ischemia for 30 min, followed by reperfusion. siRNA experiments utilized short hairpin (sh) RNA plasmid-based approaches. Transfection of shRNA was performed using cationic polymer transfection reagent. Injection of synthetic p53 shRNA into the left renal artery just after ischemia improved tubular injury, apoptosis, and the swelling of mitochondria in cells of the thick ascending limb of Henle (mTALH) at the outer medullary regions. Staining of upregulated p53 was colocalized with the inducible expression of glycogen synthase kinase-3β (GSK-3β) at mTALH after IR injury. p53 shRNA inhibited GSK-3β expression and restored β-catenin expression at mTALH. For IR-induced kidney injury, transarterial delivery of p53 siRNA is an effective pharmacological intervention. Targeting siRNA to p53 leads to an attenuation of apoptosis and mitochondrial damage through the downregulation of GSK-3β expression and upregulation of β-catenin. Local delivery of vectors such as p53 siRNA through a transaortic catheter is clinically useful in reducing the adverse effect of siRNA-related therapy.

Drp1 loss-of-function reduces cardiomyocyte oxygen dependence protecting the heart from ischemia-reperfusion injury.

PubMed

Zepeda, Ramiro; Kuzmicic, Jovan; Parra, Valentina; Troncoso, Rodrigo; Pennanen, Christian; Riquelme, Jaime A; Pedrozo, Zully; Chiong, Mario; Sánchez, Gina; Lavandero, Sergio

2014-06-01

Mitochondria are key organelles for ATP production in cardiomyocytes, which is regulated by processes of fission and fusion. We hypothesized that the mitochondria fusion protein dynamin-related protein 1 (Drp1) inhibition, attenuates ischemia-reperfusion (I/R) injury through modifications in mitochondrial metabolism. Rats were subjected to I/R through coronary artery ligation, and isolated cardiomyocytes were treated with an ischemia-mimicking solution. In vivo, cardiac function, myocardial infarction area, and mitochondrial morphology were determined, whereas in vitro, viability, mitochondrial membrane potential, intracellular ATP levels, and oxygen consumption rate (OCR) were assessed. In both models, an adenovirus expressing Drp1 dominant-negative K38A (Drp1K38A) was used to induce Drp1 loss-of-function. Our results showed that I/R stimulated mitochondrial fission. Myocardial infarction size and cell death induced by I/R were significantly reduced, whereas cardiac function after I/R was improved in Drp1K38A-treated rats compared with controls. Drp1K38A-transduced cardiomyocytes showed lower OCR with no decrease in intracellular ATP levels, and on I/R, a larger decrease in OCR with a smaller reduction in intracellular ATP level was observed. However, proton leak-associated oxygen consumption was comparatively higher in Drp1K38A-treated cardiomyocytes, suggesting a protective mitochondrial uncoupling effect against I/R. Collectively, our results show that Drp1 inhibition triggers cardioprotection by reducing mitochondrial metabolism during I/R.

MitoQ blunts mitochondrial and renal damage during cold preservation of porcine kidneys.

PubMed

Parajuli, Nirmala; Campbell, Lia H; Marine, Akira; Brockbank, Kelvin G M; Macmillan-Crow, Lee Ann

2012-01-01

Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury. In order to better translate animal studies, the inclusion of large animal models is necessary to develop safe preclinical protocols. Therefore, we tested the hypothesis that addition of MitoQ to cold storage solution preserves mitochondrial function by decreasing oxidative stress, leading to less renal tubular damage during cold preservation of porcine kidneys employing a standard criteria donor model. Results showed that cold storage significantly induced oxidative stress (nitrotyrosine), renal tubular damage, and cell death. Using High Resolution Respirometry and fresh porcine kidney biopsies to assess mitochondrial function we showed that MitoQ significantly improved complex II/III respiration of the electron transport chain following 24 hours of cold storage. In addition, MitoQ blunted oxidative stress, renal tubular damage, and cell death after 48 hours. These results suggested that MitoQ decreased oxidative stress, tubular damage and cell death by improving mitochondrial function during cold storage. Therefore this compound should be considered as an integral part of organ preservation solution prior to transplantation.

MitoQ Blunts Mitochondrial and Renal Damage during Cold Preservation of Porcine Kidneys

PubMed Central

Parajuli, Nirmala; Campbell, Lia H.; Marine, Akira; Brockbank, Kelvin G. M.; MacMillan-Crow, Lee Ann

2012-01-01

Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury. In order to better translate animal studies, the inclusion of large animal models is necessary to develop safe preclinical protocols. Therefore, we tested the hypothesis that addition of MitoQ to cold storage solution preserves mitochondrial function by decreasing oxidative stress, leading to less renal tubular damage during cold preservation of porcine kidneys employing a standard criteria donor model. Results showed that cold storage significantly induced oxidative stress (nitrotyrosine), renal tubular damage, and cell death. Using High Resolution Respirometry and fresh porcine kidney biopsies to assess mitochondrial function we showed that MitoQ significantly improved complex II/III respiration of the electron transport chain following 24 hours of cold storage. In addition, MitoQ blunted oxidative stress, renal tubular damage, and cell death after 48 hours. These results suggested that MitoQ decreased oxidative stress, tubular damage and cell death by improving mitochondrial function during cold storage. Therefore this compound should be considered as an integral part of organ preservation solution prior to transplantation. PMID:23139796

Mitochondrial dysfunction-associated OPA1 cleavage contributes to muscle degeneration: preventative effect of hydroxytyrosol acetate.

PubMed

Wang, X; Li, H; Zheng, A; Yang, L; Liu, J; Chen, C; Tang, Y; Zou, X; Li, Y; Long, J; Liu, J; Zhang, Y; Feng, Z

2014-11-13

Mitochondrial dysfunction contributes to the development of muscle disorders, including muscle wasting, muscle atrophy and degeneration. Despite the knowledge that oxidative stress closely interacts with mitochondrial dysfunction, the detailed mechanisms remain obscure. In this study, tert-butylhydroperoxide (t-BHP) was used to induce oxidative stress on differentiated C2C12 myotubes. t-BHP induced significant mitochondrial dysfunction in a time-dependent manner, accompanied by decreased myosin heavy chain (MyHC) expression at both the mRNA and protein levels. Consistently, endogenous reactive oxygen species (ROS) overproduction triggered by carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), a mitochondrial oxidative phosphorylation inhibitor, was accompanied by decreased membrane potential and decreased MyHC protein content. However, the free radical scavenger N-acetyl-L-cysteine (NAC) efficiently reduced the ROS level and restored MyHC content, suggesting a close association between ROS and MyHC expression. Meanwhile, we found that both t-BHP and FCCP promoted the cleavage of optic atrophy 1 (OPA1) from the long form into short form during the early stages. In addition, the ATPase family gene 3-like 2, a mitochondrial inner membrane protease, was also markedly increased. Moreover, OPA1 knockdown in myotubes was accompanied by decreased MyHC content, whereas NAC failed to prevent FCCP-induced MyHC decrease with OPA1 knockdown, suggesting that ROS might affect MyHC content by modulating OPA1 cleavage. In addition, hydroxytyrosol acetate (HT-AC), an important compound in virgin olive oil, could significantly prevent t-BHP-induced mitochondrial membrane potential and cell viability loss in myotubes. Specifically, HT-AC inhibited t-BHP-induced OPA1 cleavage and mitochondrial morphology changes, accompanied by improvement on mitochondrial oxygen consumption capacity, ATP productive potential and activities of mitochondrial complex I, II and V. Moreover, both t-BHP- and FCCP-induced MyHC decrease was sufficiently inhibited by HT-AC. Taken together, our data provide evidence indicating that mitochondrial dysfunction-associated OPA1 cleavage may contribute to muscle degeneration, and olive oil compounds could be effective nutrients for preventing the development of muscle disorders.

Msh1p counteracts oxidative lesion-induced instability of mtDNA and stimulates mitochondrial recombination in Saccharomyces cerevisiae.

PubMed

Kaniak, Aneta; Dzierzbicki, Piotr; Rogowska, Agata T; Malc, Ewa; Fikus, Marta; Ciesla, Zygmunt

2009-03-01

The proximity of the mitochondrial genome to the respiratory chain, a major source of ROS (radical oxygen species), makes mtDNA more vulnerable to oxidative damage than nuclear DNA. Mitochondrial BER (base excision repair) is generally considered to be the main pathway involved in the prevention of oxidative lesion-induced mutations in mtDNA. However, we previously demonstrated that the increased frequency of mitochondrial Oli(r) mutants in an ogg1Delta strain, lacking the activity of a crucial mtBER glycosylase, is reduced in the presence of plasmids encoding Msh1p, the mitochondrial homologue of the bacterial mismatch protein MutS. This finding suggested that Msh1p might be involved in the prevention of mitochondrial mutagenesis induced by oxidative stress. Here we show that a double mutant carrying the msh1-R813W allele, encoding a variant of the protein defective in the ATP hydrolysis activity, combined with deletion of SOD2, encoding the mitochondrial superoxide dismutase, displays a synergistic effect on the frequency of Oli(r) mutants, indicating that Msh1p prevents generation of oxidative lesion-induced mitochondrial mutations. We also show that double mutants carrying the msh1-R813W allele, combined with deletion of either OGG1 or APN1, the latter resulting in deficiency of the Apn1 endonuclease, exhibit a synergistic effect on the frequency of respiration-defective mutants having gross rearrangements of the mitochondrial genome. This suggests that Msh1p, Ogg1p and Apn1p play overlapping functions in maintaining the stability of mtDNA. In addition, we demonstrate, using a novel ARG8(m) recombination assay, that a surplus of Msh1p results in enhanced mitochondrial recombination. Interestingly, the mutant forms of the protein, msh1p-R813W and msh1p-G776D, fail to stimulate recombination. We postulate that the Msh1p-enhanced homologous recombination may play an important role in the prevention of oxidative lesion-induced rearrangements of the mitochondrial genome.

Sex differences in mitochondrial biogenesis determine neuronal death and survival in response to oxygen glucose deprivation and reoxygenation

PubMed Central

2014-01-01

Background Mitochondrial dysfunction has been linked to neuronal death and a wide array of neurodegenerative diseases. Previously, we have shown sex differences in mitochondria-mediated cell death pathways following hypoxia-ischemia. However, the role of mitochondrial biogenesis in hypoxic-ischemic brain injury between male vs. female has not been studied yet. Results Primary cerebellar granule neurons (CGNs), isolated from P7 male and female mice (CD-1) segregated based on visual inspection of sex, were exposed to 2 h of oxygen glucose deprivation (OGD) followed by 6–24 h of reoxygenation (Reox). Mitochondrial membrane potential (ΔΨm) and cellular ATP levels were reduced significantly in XX CGNs as compared to XY CGNs. Mitochondrial DNA (mtDNA) content was increased (>2-fold) at 2 h OGD in XY CGNs and remained increased up to 24 h of Reox compared to XX neurons and normoxia controls. The expression of mitochondrial transcription factor A (Tfam), the nuclear respiratory factor-1 (NRF-1) and the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a master regulator of mitochondrial biogenesis, were up-regulated (2-fold, ***p < 0.001) in XY CGNs but slightly reduced or remained unchanged in XX neurons. Similarly, the TFAM and PGC-1α protein levels and the mitochondrial proteins HSP60 and COXIV were increased in XY neurons only. Supportively, a balanced stimulation of fusion (Mfn 1and Mfn 2) and fission (Fis 1 and Drp 1) genes and enhanced formation of donut-shaped mitochondria were observed in XY CGNs vs. XX neurons (**p < 0.01). Conclusions Our results demonstrate that OGD/Reox alters mitochondrial biogenesis and morphological changes in a sex-specific way, influencing neuronal injury/survival differently in both sexes. PMID:24410996

Mangiferin protects mitochondrial function by preserving mitochondrial hexokinase-II in vessel endothelial cells.

PubMed

Song, Junna; Li, Yi; Song, Junmei; Hou, Fangjie; Liu, Baolin; Li, Aiying

2017-07-01

Hexokinase-II (HK-II) confers protection against cell death and this study was designed to investigate the effect of mangiferin on the regulation of mitochondrial HK-II. In vessel endothelial cells, saturated fatty acid palmitate (PA) stimulation induced HK-II detachment from mitochondria due to cellular acidification. Mangiferin reduced lactate accumulation by improving pyruvate dehydrogenase activity, promoted Akt translocation to HK-II and prevented HK-II detachment from mitochondria. Knockdown of Akt2 diminished the protective effect of mangiferin on mitochondrial HK-II, confirming the role of Akt in the regulation of HK-II. Mangiferin prevented mitochondrial permeability transition pore opening, restored mitochondrial membrane potential and thereby protected cell from apoptosis. In high-fat diet fed mice, oral administration of mangiferin induced Akt phosphorylation, increased HK-II binding to mitochondria and resultantly protected vessel endothelial function, demonstrating its protective effect on endothelial integrity in vivo. This finding provided a novel strategy for the protection of mitochondrial function in the endothelium. Copyright © 2017 Elsevier B.V. All rights reserved.

Cannabidiol protects against hepatic ischemia/reperfusion injury by attenuating inflammatory signaling and response, oxidative/nitrative stress, and cell death

PubMed Central

Mukhopadhyay, Partha; Rajesh, Mohanraj; Horváth, Béla; Bátkai, Sándor; Park, Ogyi; Tanashian, Galin; Gao, Rachel Y; Patel, Vivek; Wink, David A.; Liaudet, Lucas; Haskó, György; Mechoulam, Raphael; Pacher, Pál

2011-01-01

Ischemia-reperfusion (I/R) is a pivotal mechanism of liver damage following liver transplantation or hepatic surgery. We have investigated the effects of cannabidiol(CBD), the non-psychotropic constituent of marijuana, in a mouse model of hepatic I/R injury. I/R triggered time-dependent increases/changes in markers of liver injury (serum transaminases), hepatic oxidative/nitrative stress (4-hydroxy-2-nonenal, nitrotyrosine content/staining, gp91phox and inducible nitric oxide synthase mRNA), mitochondrial dysfunction (decreased complex I activity), inflammation (tumor necrosis factor alpha (TNF-α), cyclooxygenase 2, macrophage inflammatory protein-1α/2, inter-cellular adhesion molecule 1 mRNA levels, tissue neutrophil infiltration, nuclear factor kappa B (NF-KB) activation), stress signaling (p38MAPK and JNK) and cell death (DNA fragmentation, PARP activity, and TUNEL). CBD significantly reduced the extent of liver inflammation, oxidative/nitrative stress and cell death, and also attenuated the bacterial endotoxin-triggered NF-KB activation and TNF-α production in isolated Kupffer cells, likewise the adhesion molecules expression in primary human liver sinusoidal endothelial cells stimulated with TNF-α, and attachment of human neutrophils to the activated endothelium. These protective effects were preserved in CB2 knockout mice and were not prevented by CB1/2 antagonists in vitro. Thus, CBD may represent a novel, protective strategy against I/R injury by attenuating key inflammatory pathways and oxidative/nitrative tissue injury, independent from classical CB1/2 receptors. PMID:21362471

Microtubule antagonists activate programmed cell death (apoptosis) in cultured rat hepatocytes.

PubMed Central

Tsukidate, K.; Yamamoto, K.; Snyder, J. W.; Farber, J. L.

1993-01-01

We investigated the mechanism of lethal injury following the disruption of microtubules in cultured hepatocytes treated with vinblastine (VBL) or colchicine (COL). These agents kill hepatocytes by a process readily distinguished from two well-known pathways that lead to a loss of viability, namely, oxidative stress and inhibition of mitochondrial electron transport. Cell killing with VBL and COL was accompanied by fragmentation of DNA. Both the loss of viability and the fragmentation of DNA were prevented by the inhibition of protein synthesis within 6 hours following exposure to VBL or COL. Cell death and the fragmentation of DNA were also prevented when Ca2+ was removed from the culture medium. By contrast, the inhibition of protein kinase C prevented cell killing by VBL or COL, but did not alter the extent of DNA fragmentation. The requirements here for protein synthesis, extracellular Ca2+, and protein kinase C activity define a model of apoptosis, or programmed cell death, that seems to involve mechanisms that can be dissociated from the fragmentation of DNA. Images Figure 2 PMID:8362985

Stabilization of mitochondrial membrane potential prevents doxorubicin-induced cardiotoxicity in isolated rat heart

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montaigne, David; Marechal, Xavier; Baccouch, Riadh

2010-05-01

The present study was undertaken to examine the effects of doxorubicin on left ventricular function and cellular energy state in intact isolated hearts, and, to test whether inhibition of mitochondrial membrane potential dissipation would prevent doxorubicin-induced mitochondrial and myocardial dysfunction. Myocardial contractile performance and mitochondrial respiration were evaluated by left ventricular tension and its first derivatives and cardiac fiber respirometry, respectively. NADH levels, mitochondrial membrane potential and glucose uptake were monitored non-invasively via epicardial imaging of the left ventricular wall of Langendorff-perfused rat hearts. Heart performance was reduced in a time-dependent manner in isolated rat hearts perfused with Krebs-Henseleit solutionmore » containing 1 muM doxorubicin. Compared with controls, doxorubicin induced acute myocardial dysfunction (dF/dt{sub max} of 105 +- 8 mN/s in control hearts vs. 49 +- 7 mN/s in doxorubicin-treated hearts; *p < 0.05). In cardiac fibers prepared from perfused hearts, doxorubicin induced depression of mitochondrial respiration (respiratory control ratio of 4.0 +- 0.2 in control hearts vs. 2.2 +- 0.2 in doxorubicin-treated hearts; *p < 0.05) and cytochrome c oxidase kinetic activity (24 +- 1 muM cytochrome c/min/mg in control hearts vs. 14 +- 3 muM cytochrome c/min/mg in doxorubicin-treated hearts; *p < 0.05). Acute cardiotoxicity induced by doxorubicin was accompanied by NADH redox state, mitochondrial membrane potential, and glucose uptake reduction. Inhibition of mitochondrial permeability transition pore opening by cyclosporine A largely prevented mitochondrial membrane potential dissipation, cardiac energy state and dysfunction. These results suggest that in intact hearts an impairment of mitochondrial metabolism is involved in the development of doxorubicin cardiotoxicity.« less

Activation of sirtuin 1/3 improves vascular hyporeactivity in severe hemorrhagic shock by alleviation of mitochondrial damage

PubMed Central

Li, Pengyun; Meng, Xianzhong; Bian, Huining; Burns, Nana; Zhao, Ke-seng; Song, Rui

2015-01-01

Vascular hyporeactivity is one of the major causes responsible for refractory hypotension and associated mortality in severe hemorrhagic shock. Mitochondrial permeability transition (mPT) pore opening in arteriolar smooth muscle cells (ASMCs) is involved in the pathogenesis of vascular hyporeactivity. However, the molecular mechanism underlying mitochondrial injury in ASMCs during hemorrhagic shock is not well understood. Here we produced an in vivo model of severe hemorrhagic shock in adult Wistar rats. We found that sirtuin (SIRT)1/3 protein levels and deacetylase activities were decreased in ASMCs following severe shock. Immunofluorescence staining confirmed reduced levels of SIRT1 in the nucleus and SIRT3 in the mitochondria, respectively. Acetylation of cyclophilin D (CyPD), a component of mPT pore, was increased. SIRT1 activators suppressed mPT pore opening and ameliorated mitochondrial injury in ASMCs after severe shock. Furthermore, administration of SIRT1 activators improved vasoreactivity in rats under severe shock. Our data suggest that epigenetic mechanisms, namely histone post-translational modifications, are involved in regulation of mPT by SIRT1/SIRT3- mediated deacetylation of CyPD. SIRT1/3 is a promising therapeutic target for the treatment of severe hemorrhagic shock. PMID:26473372

Hepatocellular toxicity of oxalicumone A via oxidative stress injury and mitochondrial dysfunction in healthy human liver cells.

PubMed

Shi, Si; Yao, Limei; Guo, Kunbin; Wang, Xiangyu; Wang, Qi; Li, Weirong

2018-01-01

The marine‑derived oxalicumone A (POA) has been demonstrated as a potent anti‑tumor bioactive agent for a variety of human carcinoma, but to the best of our knowledge, remains to be evaluated in healthy liver cells. As many drugs distribute preferentially in the liver, the present study aimed to investigate the effects of POA on apoptosis, oxidative stress and mitochondrial function in L‑02 healthy liver cells. A Cell‑Counting kit‑8 assay demonstrated that POA inhibits the proliferation of L‑02 cells in a dose‑ and time‑dependent manner. Furthermore, POA induced apoptosis by increasing the percentage of cells in early apoptosis and the sub‑G1 cell cycle, along with causing S‑phase arrest in L‑02 cells. Additionally, POA activated caspase 3, increased the protein expression levels of Fas ligand and B‑cell lymphoma X‑associated protein, and decreased the expression of the anti‑apoptotic protein B‑cell lymphoma 2. POA additionally reduced the content of GSH and the activity of superoxide dismutase, elevated malondialdehyde and nitric oxide levels, increased reactive oxygen species production and the levels of alanine aminotransferase and aspartate aminotransferase, which suggested that POA induced lipid peroxidation injury in L‑02 cells and that oxidative stress serves an important role. Furthermore, POA caused alternations of mitochondrial function, including an abrupt depletion of adenosine triphosphate synthesis, mitochondrial permeability transition pore opening and depletion of mitochondrial membrane potential in L‑02 cells. These data suggested that POA exerts cytotoxicity, at least in part, by inducing oxidative stress, mitochondrial dysfunction, and eventually apoptosis. Changes in mitochondrial function and oxidative stress by POA may therefore be critical in POA‑induced toxicity in L‑02 cells.

Cannabidiol Protects against Doxorubicin-Induced Cardiomyopathy by Modulating Mitochondrial Function and Biogenesis.

PubMed

Hao, Enkui; Mukhopadhyay, Partha; Cao, Zongxian; Erdélyi, Katalin; Holovac, Eileen; Liaudet, Lucas; Lee, Wen-Shin; Haskó, György; Mechoulam, Raphael; Pacher, Pál

2015-01-06

Doxorubicin (DOX) is a widely used, potent chemotherapeutic agent; however, its clinical application is limited because of its dose-dependent cardiotoxicity. DOX's cardiotoxicity involves increased oxidative/nitrative stress, impaired mitochondrial function in cardiomyocytes/endothelial cells and cell death. Cannabidiol (CBD) is a nonpsychotropic constituent of marijuana, which is well tolerated in humans, with antioxidant, antiinflammatory and recently discovered antitumor properties. We aimed to explore the effects of CBD in a well-established mouse model of DOX-induced cardiomyopathy. DOX-induced cardiomyopathy was characterized by increased myocardial injury (elevated serum creatine kinase and lactate dehydrogenase levels), myocardial oxidative and nitrative stress (decreased total glutathione content and glutathione peroxidase 1 activity, increased lipid peroxidation, 3-nitrotyrosine formation and expression of inducible nitric oxide synthase mRNA), myocardial cell death (apoptotic and poly[ADP]-ribose polymerase 1 [PARP]-dependent) and cardiac dysfunction (decline in ejection fraction and left ventricular fractional shortening). DOX also impaired myocardial mitochondrial biogenesis (decreased mitochondrial copy number, mRNA expression of peroxisome proliferator-activated receptor γ coactivator 1-alpha, peroxisome proliferator-activated receptor alpha, estrogen-related receptor alpha), reduced mitochondrial function (attenuated complex I and II activities) and decreased myocardial expression of uncoupling protein 2 and 3 and medium-chain acyl-CoA dehydrogenase mRNA. Treatment with CBD markedly improved DOX-induced cardiac dysfunction, oxidative/nitrative stress and cell death. CBD also enhanced the DOX-induced impaired cardiac mitochondrial function and biogenesis. These data suggest that CBD may represent a novel cardioprotective strategy against DOX-induced cardiotoxicity, and the above-described effects on mitochondrial function and biogenesis may contribute to its beneficial properties described in numerous other models of tissue injury.

Cannabidiol Protects against Doxorubicin-Induced Cardiomyopathy by Modulating Mitochondrial Function and Biogenesis

PubMed Central

Hao, Enkui; Mukhopadhyay, Partha; Cao, Zongxian; Erdélyi, Katalin; Holovac, Eileen; Liaudet, Lucas; Lee, Wen-Shin; Haskó, György; Mechoulam, Raphael; Pacher, Pál

2015-01-01

Doxorubicin (DOX) is a widely used, potent chemotherapeutic agent; however, its clinical application is limited because of its dose-dependent cardiotoxicity. DOX’s cardiotoxicity involves increased oxidative/nitrative stress, impaired mitochondrial function in cardiomyocytes/endothelial cells and cell death. Cannabidiol (CBD) is a nonpsychotropic constituent of marijuana, which is well tolerated in humans, with antioxidant, antiinflammatory and recently discovered antitumor properties. We aimed to explore the effects of CBD in a well-established mouse model of DOX-induced cardiomyopathy. DOX-induced cardiomyopathy was characterized by increased myocardial injury (elevated serum creatine kinase and lactate dehydrogenase levels), myocardial oxidative and nitrative stress (decreased total glutathione content and glutathione peroxidase 1 activity, increased lipid peroxidation, 3-nitrotyrosine formation and expression of inducible nitric oxide synthase mRNA), myocardial cell death (apoptotic and poly[ADP]-ribose polymerase 1 [PARP]-dependent) and cardiac dysfunction (decline in ejection fraction and left ventricular fractional shortening). DOX also impaired myocardial mitochondrial biogenesis (decreased mitochondrial copy number, mRNA expression of peroxisome proliferator-activated receptor γ coactivator 1-alpha, peroxisome proliferator-activated receptor alpha, estrogen-related receptor alpha), reduced mitochondrial function (attenuated complex I and II activities) and decreased myocardial expression of uncoupling protein 2 and 3 and medium-chain acyl-CoA dehydrogenase mRNA. Treatment with CBD markedly improved DOX-induced cardiac dysfunction, oxidative/nitrative stress and cell death. CBD also enhanced the DOX-induced impaired cardiac mitochondrial function and biogenesis. These data suggest that CBD may represent a novel cardioprotective strategy against DOX-induced cardiotoxicity, and the above-described effects on mitochondrial function and biogenesis may contribute to its beneficial properties described in numerous other models of tissue injury. PMID:25569804

Neuroprotective effects of lycopene in spinal cord injury in rats via antioxidative and anti-apoptotic pathway.

PubMed

Hu, Wei; Wang, Hongbo; Liu, Zhenfeng; Liu, Yanlu; Wang, Rong; Luo, Xiao; Huang, Yifei

2017-03-06

Oxidative damage induced-mitochondrial dysfunction and apoptosis has been widely studied in spinal cord injury (SCI). Lycopene, a polyunsaturated hydrocarbon, has the highest antioxidant capacity compared to the other carotenoids. However, the role of lycopene in SCI is unknown. In the present study, we evaluated the antioxidant effects of lycopene on mitochondrial dysfunction and apoptosis following T10 contusion SCI in rats. The rats were randomized into 5 groups: the sham group, the SCI group and the SCI pre-treated with lycopene (5, 10, or 20mg/kg) group. The SCI group showed increased malondialdehyde (MDA) content, decreased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) ability, which indicated that SCI could induce oxidative damage. What's more, the SCI group showed decreased mRNA expression of cytochrome b and mitochondrial transcription factor A (Tfam), and decreased mitochondrial membrane potential (ΔYm), which indicated that SCI could induce mitochondrial dysfunction. Besides, the SCI group showed decreased protein expression of bcl-2 and mitochondrial cytochrome C, increased protein expression of cytosolic cytochrome C, cleaved caspase-9, cleaved caspase-3 and bax, and increased TUNEL-positive cell numbers, which indicated that SCI could induce cell apoptosis. Fortunately, the lycopene treatment significantly ameliorated oxidative damage, mitochondrial dysfunction and cell apoptosis via the reversion of those parameters described above in the dose of lycopene of 10 and 20mg/kg. In addition, lycopene significantly ameliorated the hind limb motor disturbances in the SCI+lyco10 group and the SCI+lyco20 group compared with the SCI group. These results suggested that lycopene administration could improve total antioxidant status and might have neuroprotective effects on SCI. Copyright © 2017 Elsevier B.V. All rights reserved.

Mitochondrial Modulation by Epigallocatechin 3-Gallate Ameliorates Cisplatin Induced Renal Injury through Decreasing Oxidative/Nitrative Stress, Inflammation and NF-kB in Mice

PubMed Central

Wang, Xueping; Wang, Ping; Fu, Guanghou; Meng, Hongzhou; Wang, Yimin; Jin, Baiye

2015-01-01

Cancer chemotherapy drug cisplatin is known for its nephrotoxicity. The aim of this study is to investigate whether Epigallocatechin 3-Gallate (EGCG) can reduce cisplatin mediated side effect in kidney and to understand its mechanism of protection against tissue injury. We used a well-established 3-day cisplatin induced nephrotoxicity mice model where EGCG were administered. EGCG is a major active compound in Green Tea and have strong anti-oxidant and anti-inflammatory properties. EGCG protected against cisplatin induced renal dysfunction as measured by serum creatinine and blood urea nitrogen (BUN). EGCG improved cisplatin induced kidney structural damages such as tubular dilatation, cast formation, granulovaculoar degeneration and tubular cell necrosis as evident by PAS staining. Cisplatin induced kidney specific mitochondrial oxidative stress, impaired activities of mitochondrial electron transport chain enzyme complexes, impaired anti-oxidant defense enzyme activities such as glutathione peroxidase (GPX) and manganese superoxide dismutase (MnSOD) in mitochondria, inflammation (tumor necrosis factor α and interleukin 1β), increased accumulation of NF-κB in nuclear fraction, p53 induction, and apoptotic cell death (caspase 3 activity and DNA fragmentation). Treatment of mice with EGCG markedly attenuated cisplatin induced mitochondrial oxidative/nitrative stress, mitochondrial damages to electron transport chain activities and antioxidant defense enzyme activities in mitochondria. These mitochondrial modulations by EGCG led to protection mechanism against cisplatin induced inflammation and apoptotic cell death in mice kidney. As a result, EGCG improved renal function in cisplatin mediated kidney damage. In addition to that, EGCG attenuated cisplatin induced apoptotic cell death and mitochondrial reactive oxygen species (ROS) generation in human kidney tubular cell line HK-2. Thus, our data suggest that EGCG may represent new promising adjunct candidate for cisplatin. PMID:25875356

Inhibition of the mitochondrial pyruvate carrier protects from excitotoxic neuronal death.

PubMed

Divakaruni, Ajit S; Wallace, Martina; Buren, Caodu; Martyniuk, Kelly; Andreyev, Alexander Y; Li, Edward; Fields, Jerel A; Cordes, Thekla; Reynolds, Ian J; Bloodgood, Brenda L; Raymond, Lynn A; Metallo, Christian M; Murphy, Anne N

2017-04-03

Glutamate is the dominant excitatory neurotransmitter in the brain, but under conditions of metabolic stress it can accumulate to excitotoxic levels. Although pharmacologic modulation of excitatory amino acid receptors is well studied, minimal consideration has been given to targeting mitochondrial glutamate metabolism to control neurotransmitter levels. Here we demonstrate that chemical inhibition of the mitochondrial pyruvate carrier (MPC) protects primary cortical neurons from excitotoxic death. Reductions in mitochondrial pyruvate uptake do not compromise cellular energy metabolism, suggesting neuronal metabolic flexibility. Rather, MPC inhibition rewires mitochondrial substrate metabolism to preferentially increase reliance on glutamate to fuel energetics and anaplerosis. Mobilizing the neuronal glutamate pool for oxidation decreases the quantity of glutamate released upon depolarization and, in turn, limits the positive-feedback cascade of excitotoxic neuronal injury. The finding links mitochondrial pyruvate metabolism to glutamatergic neurotransmission and establishes the MPC as a therapeutic target to treat neurodegenerative diseases characterized by excitotoxicity. © 2017 Divakaruni et al.

Inhibition of the mitochondrial pyruvate carrier protects from excitotoxic neuronal death

PubMed Central

Wallace, Martina; Buren, Caodu; Martyniuk, Kelly; Andreyev, Alexander Y.; Li, Edward; Fields, Jerel A.; Cordes, Thekla; Reynolds, Ian J.; Bloodgood, Brenda L.; Metallo, Christian M.

2017-01-01

Glutamate is the dominant excitatory neurotransmitter in the brain, but under conditions of metabolic stress it can accumulate to excitotoxic levels. Although pharmacologic modulation of excitatory amino acid receptors is well studied, minimal consideration has been given to targeting mitochondrial glutamate metabolism to control neurotransmitter levels. Here we demonstrate that chemical inhibition of the mitochondrial pyruvate carrier (MPC) protects primary cortical neurons from excitotoxic death. Reductions in mitochondrial pyruvate uptake do not compromise cellular energy metabolism, suggesting neuronal metabolic flexibility. Rather, MPC inhibition rewires mitochondrial substrate metabolism to preferentially increase reliance on glutamate to fuel energetics and anaplerosis. Mobilizing the neuronal glutamate pool for oxidation decreases the quantity of glutamate released upon depolarization and, in turn, limits the positive-feedback cascade of excitotoxic neuronal injury. The finding links mitochondrial pyruvate metabolism to glutamatergic neurotransmission and establishes the MPC as a therapeutic target to treat neurodegenerative diseases characterized by excitotoxicity. PMID:28254829

Mitochondrial biotransformation of ω-(phenoxy)alkanoic acids, 3-(phenoxy)acrylic acids, and ω-(1-methyl-1H-imidazol-2-ylthio)alkanoic acids: A prodrug strategy for targeting cytoprotective antioxidants to mitochondria

PubMed Central

Roser, Kurt S.; Brookes, Paul S.; Wojtovich, Andrew P.; Olson, Leif P.; Shojaie, Jalil; Parton, Richard L.; Anders, M. W.

2010-01-01

Mitochondrial reactive oxygen species (ROS) generation and the attendant mitochondrial dysfunction are implicated in a range of disease states. The objective of the present studies was to test the hypothesis that the mitochondrial β-oxidation pathway could be exploited to deliver and biotransform the prodrugs ω-(phenoxy)alkanoic acids, 3-(phenoxy)acrylic acids, and ω-(1-methyl-1H-imidazol-2-ylthio)alkanoic acids to the corresponding phenolic antioxidants or methimazole. 3 -and 5-(Phenoxy)alkanoic acids and methyl-substituted analogs were biotransformed to phenols; rates of biotransformation decreased markedly with methyl-group substitution on the phenoxy moiety. 2,6-Dimethylphenol formation from the analogs 3-([2,6-dimethylphenoxy]methylthio)propanoic acid and 3-(2,6-dimethylphenoxy)acrylic acid was greater than that observed with ω-(2,6-dimethylphenoxy)alkanoic acids. 3- and 5-(1-Methyl-1H-imidazol-2-ylthio)alkanoic acids were rapidly biotransformed to the antioxidant methimazole and conferred significant cytoprotection against hypoxia-reoxygenation injury in isolated cardiomyocytes. Both 3-(2,6-dimethylphenoxy)propanoic acid and 3-(2,6-dimethylphenoxy)acrylic acid also afforded cytoprotection against hypoxia-reoxygenation injury in isolated cardiomyocytes. These results demonstrate that mitochondrial β-oxidation is a potentially useful delivery system for targeting antioxidants to mitochondria. PMID:20129794

Three-dimensional analysis of somatic mitochondrial dynamics in fission-deficient injured motor neurons using FIB/SEM.

PubMed

Tamada, Hiromi; Kiryu-Seo, Sumiko; Hosokawa, Hiroki; Ohta, Keisuke; Ishihara, Naotada; Nomura, Masatoshi; Mihara, Katsuyoshi; Nakamura, Kei-Ichiro; Kiyama, Hiroshi

2017-08-01

Mitochondria undergo morphological changes through fusion and fission for their quality control, which are vital for neuronal function. In this study, we examined three-dimensional morphologies of mitochondria in motor neurons under normal, nerve injured, and nerve injured plus fission-impaired conditions using the focused ion beam/scanning electron microscopy (FIB/SEM), because the FIB/SEM technology is a powerful tool to demonstrate both 3D images of whole organelle and the intra-organellar structure simultaneously. Crossing of dynamin-related protein 1 (Drp1) gene-floxed mice with neuronal injury-specific Cre driver mice, Atf3:BAC Tg mice, allowed for Drp1 ablation specifically in injured neurons. FIB/SEM analysis demonstrated that somatic mitochondrial morphologies in motor neurons were not altered before or after nerve injury. However, the fission impairment resulted in prominent somatic mitochondrial enlargement, which initially induced complex morphologies with round regions and long tubular processes, subsequently causing a decrease in the number of processes and further enlargement of the round regions, which eventually resulted in big spheroidal mitochondria without processes. The abnormal mitochondria exhibited several degradative morphologies: local or total cristae collapse, vacuolization, and mitophagy. These suggest that mitochondrial fission is crucial for maintaining mitochondrial integrity in injured motor neurons, and multiple forms of mitochondria degradation may accelerate neuronal degradation. © 2017 Wiley Periodicals, Inc.

β-Sitosterol enhances cellular glutathione redox cycling by reactive oxygen species generated from mitochondrial respiration: protection against oxidant injury in H9c2 cells and rat hearts.

PubMed

Wong, Hoi Shan; Chen, Na; Leong, Pou Kuan; Ko, Kam Ming

2014-07-01

Herba Cistanches (Cistanche deserticola Y. C. Ma) is a 'Yang-invigorating' tonic herb in Chinese medicine. Preliminary chemical analysis indicated that β-sitosterol (BS) is one of the chemical constituents in an active fraction of Herba Cistanches. To investigate whether BS is an active ingredient of Herba Cistanches, the effects of BS on H9c2 cells and rat hearts were examined. The results indicated that BS stimulated the mitochondrial ATP generation capacity in H9c2 cells, which was associated with the increased production of mitochondrial reactive oxygen species. BS also stimulated mitochondrial state 3 and state 4 respiration, with the resultant decrease in coupling efficiency. BS produced an up-regulation of cellular glutathione redox cycling and protected against hypoxia/reoxygenation-induced apoptosis in H9c2 cells. However, the protective effect of BS against myocardial ischemia/reperfusion injury was seen in female but not male rats ex vivo. The cardioprotection afforded by BS was likely mediated by an up-regulation of mitochondrial glutathione redox cycling in female rat hearts. In conclusion, the ensemble of results suggests that BS is an active ingredient of Herba Cistanches. The gender-dependent effect of BS on myocardial protection will further be investigated. Copyright © 2013 John Wiley & Sons, Ltd.

Betanin attenuates paraquat-induced liver toxicity through a mitochondrial pathway.

PubMed

Han, Junyan; Zhang, Zongju; Yang, Shaobin; Wang, Jun; Yang, Xuelian; Tan, Dehong

2014-08-01

We attempted to determine whether betanin (from natural pigments) that has anti-oxidant properties would be protective against paraquat-induced liver injury in Sprague-Dawley rats. Paraquat was injected intraperitoneally into rats to induce liver toxicity. The rats were randomly divided into four groups: a control group, a paraquat group, and two groups that received betanin at doses of 25 and 100mg/kg/day three days before and two days after they were administered paraquat. We evaluated liver histopathology, serum liver enzymatic activities, oxidative stress, cytochrome P450 (CYP) 3A2 mRNA expression, and mitochondrial damage. The rats that were injected with paraquat incurred liver injury, evidenced by histological changes and elevated serum aspartate aminotransferase and alanine aminotransferase levels; paraquat also led to oxidative stress, an increase of cytochrome P450 3A2 mRNA expression, and mitochondrial damage, indicated by mitochondrial membrane swelling, reduced mitochondrial cytochrome C, and apoptosis-inducing factor protein levels. Pathological damage and all of the above mentioned markers were lesser in the animals treated with betanin than in those who received paraquat alone. Betanin had a protective effect against paraquat-induced liver damage in rats. The mechanism of the protection appears to be the inhibition of CYP 3A2 expression and protection of mitochondria. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Young Man with Non-alcoholic Steatohepatitis and Serum Anti-mitochondrial Antibody Positivity: A Case Report.

PubMed

Seike, Takuya; Komura, Takuya; Shimizu, Yoshiaki; Omura, Hitoshi; Kumai, Tatsuo; Kagaya, Takashi; Ohta, Hajime; Kawashima, Atsuhiro; Harada, Kenichi; Kaneko, Shuichi; Unoura, Masashi

2018-06-06

A 37-year-old obese man who was a social drinker was admitted to our hospital to undergo a detailed examination for liver injury with anti-mitochondrial antibody positivity. Abdominal ultrasonography revealed moderate fatty liver. A histological analysis showed steatosis of approximately 30% of the hepatocytes, focal necrosis, a few ballooning hepatocytes and lobular inflammation suggestive of steatohepatitis, epithelioid granuloma and irregularity of the sequence of the bile duct epithelium accompanied by lymphocyte infiltration suggestive of chronic cholangitis. He was diagnosed with non-alcoholic steatohepatitis complicated with primary biliary cholangitis. His liver injury was improved by weight loss and high-dose ursodeoxycholic acid treatment.

Oxidative stress and myocardial injury in the diabetic heart

PubMed Central

Ansley, David M.; Wang, Baohua

2013-01-01

Reactive oxygen or nitrogen species play an integral role in both myocardial injury and repair. This dichotomy is differentiated at the level of species type, amount, duration of free radical generated. Homeostatic mechanisms designed to prevent free radical generation in the first instance, scavenge, or enzymatically convert them to less toxic forms and water, play crucial roles in maintenance of cellular structure and function. The outcome between functional recovery and dysfunction is dependent upon the inherent ability of these homeostatic antioxidant defenses to withstand acute free radical generation, in the order of seconds to minutes. Alternatively, pre-existent antioxidant capacity (from intracellular and extracellular sources) may regulate the degree of free radical generation. This converts reactive oxygen and nitrogen species to the role of second messenger involved in cell signalling. The adaptive capacity of the cell is altered by the balance between death or survival signal converging at the level of the mitochondria, with distinct pathophysiologic consequences that extends the period of injury from hours to days and weeks. Hyperglycemia, hyperlipidemia, and insulin resistance enhance oxidative stress in diabetic myocardium that cannot adapt to ischemia reperfusion. Altered glucose flux, mitochondrial derangements and nitric oxide synthase uncoupling in the presence of decreased antioxidant defense and impaired prosurvival cell signalling may render the diabetic myocardium more vulnerable to injury, remodelling and heart failure. PMID:23011912

Vasopressin Mediates the Renal Damage Induced by Limited Fructose Rehydration in Recurrently Dehydrated Rats.

PubMed

García-Arroyo, Fernando E; Tapia, Edilia; Blas-Marron, Mónica G; Gonzaga, Guillermo; Silverio, Octaviano; Cristóbal, Magdalena; Osorio, Horacio; Arellano-Buendía, Abraham S; Zazueta, Cecilia; Aparicio-Trejo, Omar Emiliano; Reyes-García, Juan G; Pedraza-Chaverri, José; Soto, Virgilia; Roncal-Jiménez, Carlos; Johnson, Richard J; Sánchez-Lozada, Laura G

2017-01-01

Recurrent dehydration and heat stress cause chronic kidney damage in experimental animals. The injury is exacerbated by rehydration with fructose-containing beverages. Fructose may amplify dehydration-induced injury by directly stimulating vasopressin release and also by acting as a substrate for the aldose reductase-fructokinase pathway, as both of these systems are active during dehydration. The role of vasopressin in heat stress associated injury has not to date been explored. Here we show that the amplification of renal damage mediated by fructose in thermal dehydration is mediated by vasopressin. Fructose rehydration markedly enhanced vasopressin (copeptin) levels and activation of the aldose reductase-fructokinase pathway in the kidney. Moreover, the amplification of the renal functional changes (decreased creatinine clearance and tubular injury with systemic inflammation, renal oxidative stress, and mitochondrial dysfunction) were prevented by the blockade of V1a and V2 vasopressin receptors with conivaptan. On the other hand, there are also other operative mechanisms when water is used as rehydration fluid that produce milder renal damage that is not fully corrected by vasopressin blockade. Therefore, we clearly showed evidence of the cross-talk between fructose, even at small doses, and vasopressin that interact to amplify the renal damage induced by dehydration. These data may be relevant for heat stress nephropathy as well as for other renal pathologies due to the current generalized consumption of fructose and deficient hydration habits.

Salvianic acid A sodium protects HUVEC cells against tert-butyl hydroperoxide induced oxidative injury via mitochondria-dependent pathway.

PubMed

Jia, Dan; Li, Tian; Chen, Xiaofei; Ding, Xuan; Chai, Yifeng; Chen, Alex F; Zhu, Zhenyu; Zhang, Chuan

2018-01-05

Salvianic acid A (Danshensu) is a major water-soluble component extracted from Salvia miltiorrhiza (Danshen), which has been widely used in clinic in China for treatment of cardiovascular diseases (CVDs). This study aimed to investigate the protective effects of salvianic acid A sodium (SAAS) against tert-butyl hydroperoxide (t-BHP) induced human umbilical vein endothelial cell (HUVEC) oxidative injury and the underlying molecular mechanisms. In the antioxidant activity-assessing model, SAAS pretreatment significantly ameliorated the cell growth inhibition and apoptosis induced by t-BHP. An ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) based-metabolic profiling was developed to investigate the metabolic changes of HUVEC cells in response to t-BHP and SAAS. The results revealed that t-BHP injury upregulated 13 metabolites mainly involved in tryptophan metabolism and phenylalanine metabolism which were highly correlated with mitochondrial function and oxidative stress, and 50 μM SAAS pretreatment effectively reversed these metabolic changes. Further biomedical research indicated that SAAS pretreatment reduced the t-BHP induced increase of lactate dehydrogenase (LDH), intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and mitochondrial membrane potential (MMP), and the decrease of key antioxidant enzymes through mitochondria antioxidative pathways via JAK2/STAT3 and PI3K/Akt/GSK-3β signalings. Taken together, our results suggested that SAAS may protect HUVEC cells against t-BHP induced oxidative injury via mitochondrial antioxidative defense system. Copyright © 2017 Elsevier B.V. All rights reserved.

Kidney-Heart Interactions in Acute Kidney Injury.

PubMed

Doi, Kent

2016-01-01

Acute kidney injury (AKI) is a common complication in critically ill patients treated in intensive care units. Renal replacement therapy (RRT)-requiring AKI occurs in approximately 5-10% patients in intensive care unit and their mortality rate is unacceptably high (50-60%), despite sufficient control of uremia using remarkably advanced modern RRT techniques. This suggests that there are unrecognized organ interactions following AKI that could worsen the outcomes. Cardiorenal syndrome has been defined based on clinical observations that acute and chronic heart failure causes kidney injury and AKI and that chronic kidney disease worsens heart diseases. Possible pathways that connect these 2 organs have been suggested; however, the precise mechanisms are yet to be clarified, particularly in AKI-induced cardiac dysfunction. This review focuses on acute cardiac dysfunction in the setting of AKI. A recent animal study demonstrated the dysregulation of mitochondrial dynamics caused by an increased dynamin-related protein 1 expression and cellular apoptosis of the heart in a renal ischemia reperfusion model. Although the precise mechanisms that induce cardiac mitochondrial injury in AKI remain unclear, cardiac mitochondria injury could be a novel candidate of drug targets against high mortality in severe AKI. © 2016 S. Karger AG, Basel.

Lycopene Prevents Amyloid [Beta]-Induced Mitochondrial Oxidative Stress and Dysfunctions in Cultured Rat Cortical Neurons.

PubMed

Qu, Mingyue; Jiang, Zheng; Liao, Yuanxiang; Song, Zhenyao; Nan, Xinzhong

2016-06-01

Brains affected by Alzheimer's disease (AD) show a large spectrum of mitochondrial alterations at both morphological and genetic level. The causal link between β-amyloid (Aβ) and mitochondrial dysfunction has been established in cellular models of AD. We observed previously that lycopene, a member of the carotenoid family of phytochemicals, could counteract neuronal apoptosis and cell damage induced by Aβ and other neurotoxic substances, and that this neuroprotective action somehow involved the mitochondria. The present study aims to investigate the effects of lycopene on mitochondria in cultured rat cortical neurons exposed to Aβ. It was found that lycopene attenuated Aβ-induced oxidative stress, as evidenced by the decreased intracellular reactive oxygen species generation and mitochondria-derived superoxide production. Additionally, lycopene ameliorated Aβ-induced mitochondrial morphological alteration, opening of the mitochondrial permeability transition pores and the consequent cytochrome c release. Lycopene also improved mitochondrial complex activities and restored ATP levels in Aβ-treated neuron. Furthermore, lycopene prevented mitochondrial DNA damages and improved the protein level of mitochondrial transcription factor A in mitochondria. Those results indicate that lycopene protects mitochondria against Aβ-induced damages, at least in part by inhibiting mitochondrial oxidative stress and improving mitochondrial function. These beneficial effects of lycopene may account for its protection against Aβ-induced neurotoxicity.

Inhibition of mTOR Prevents ROS Production Initiated by Ethidium Bromide-Induced Mitochondrial DNA Depletion

PubMed Central

Nacarelli, Timothy; Azar, Ashley; Sell, Christian

2014-01-01

The regulation of mitochondrial mass and DNA content involves a complex interaction between mitochondrial DNA replication machinery, functional components of the electron transport chain, selective clearance of mitochondria, and nuclear gene expression. In order to gain insight into cellular responses to mitochondrial stress, we treated human diploid fibroblasts with ethidium bromide at concentrations that induced loss of mitochondrial DNA over a period of 7 days. The decrease in mitochondrial DNA was accompanied by a reduction in steady state levels of the mitochondrial DNA binding protein, TFAM, a reduction in several electron transport chain protein levels, increased mitochondrial and total cellular ROS, and activation of p38 MAPK. However, there was an increase in mitochondrial mass and voltage dependent anion channel levels. In addition, mechanistic target of rapamycin (mTOR) activity, as judged by p70S6K targets, was decreased while steady state levels of p62/SQSTM1 and Parkin were increased. Treatment of cells with rapamycin created a situation in which cells were better able to adapt to the mitochondrial dysfunction, resulting in decreased ROS and increased cell viability but did not prevent the reduction in mitochondrial DNA. These effects may be due to a more efficient flux through the electron transport chain, increased autophagy, or enhanced AKT signaling, coupled with a reduced growth rate. Together, the results suggest that mTOR activity is affected by mitochondrial stress, which may be part of the retrograde signal system required for normal mitochondrial homeostasis. PMID:25104948

Lower susceptibility of female mice to acetaminophen hepatotoxicity: Role of mitochondrial glutathione, oxidant stress and c-jun N-terminal kinase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Kuo; Williams, C. David; McGill, Mitchell R.

Acetaminophen (APAP) overdose causes severe hepatotoxicity in animals and humans. However, the mechanisms underlying the gender differences in susceptibility to APAP overdose in mice have not been clarified. In our study, APAP (300 mg/kg) caused severe liver injury in male mice but 69–77% lower injury in females. No gender difference in metabolic activation of APAP was found. Hepatic glutathione (GSH) was rapidly depleted in both genders, while GSH recovery in female mice was 2.6 fold higher in the mitochondria at 4 h, and 2.5 and 3.3 fold higher in the total liver at 4 h and 6 h, respectively. Thismore » faster recovery of GSH, which correlated with greater induction of glutamate-cysteine ligase, attenuated mitochondrial oxidative stress in female mice, as suggested by a lower GSSG/GSH ratio at 6 h (3.8% in males vs. 1.4% in females) and minimal centrilobular nitrotyrosine staining. While c-jun N-terminal kinase (JNK) activation was similar at 2 and 4 h post-APAP, it was 3.1 fold lower at 6 h in female mice. However, female mice were still protected by the JNK inhibitor SP600125. 17β-Estradiol pretreatment moderately decreased liver injury and oxidative stress in male mice without affecting GSH recovery. Conclusion: The lower susceptibility of female mice is achieved by the improved detoxification of reactive oxygen due to accelerated recovery of mitochondrial GSH levels, which attenuates late JNK activation and liver injury. However, even the reduced injury in female mice was still dependent on JNK. While 17β-estradiol partially protects male mice, it does not affect hepatic GSH recovery. - Highlights: • Female mice are less susceptible to acetaminophen overdose than males. • GSH depletion and protein adduct formation are similar in both genders. • Recovery of hepatic GSH levels is faster in females and correlates with Gclc. • Reduced oxidant stress in females leads to reduced JNK activation. • JNK activation and mitochondrial translocation are critical in females.« less

Attenuation of Skeletal Muscle and Renal Injury to the Lower Limb following Ischemia-Reperfusion Using mPTP Inhibitor NIM-811

PubMed Central

Garbaisz, David; Turoczi, Zsolt; Aranyi, Peter; Fulop, Andras; Rosero, Oliver; Hermesz, Edit; Ferencz, Agnes; Lotz, Gabor; Harsanyi, Laszlo; Szijarto, Attila

2014-01-01

Introduction Operation on the infrarenal aorta and large arteries of the lower extremities may cause rhabdomyolysis of the skeletal muscle, which in turn may induce remote kidney injury. NIM-811 (N-metyl-4-isoleucine-cyclosporine) is a mitochondria specific drug, which can prevent ischemic-reperfusion (IR) injury, by inhibiting mitochondrial permeability transition pores (mPTP). Objectives Our aim was to reduce damages in the skeletal muscle and the kidney after IR of the lower limb with NIM-811. Materials and methods Wistar rats underwent 180 minutes of bilateral lower limb ischemia and 240 minutes of reperfusion. Four animal groups were formed called Sham (receiving vehicle and sham surgery), NIM-Sham (receiving NIM-811 and sham surgery), IR (receiving vehicle and surgery), and NIM-IR (receiving NIM-811 and surgery). Serum, urine and histological samples were taken at the end of reperfusion. NADH-tetrazolium staining, muscle Wet/Dry (W/D) ratio calculations, laser Doppler-flowmetry (LDF) and mean arterial pressure (MAP) monitoring were performed. Renal peroxynitrite concentration, serum TNF-α and IL-6 levels were measured. Results Less significant histopathological changes were observable in the NIM-IR group as compared with the IR group. Serum K+ and necroenzyme levels were significantly lower in the NIM-IR group than in the IR group (LDH: p<0.001; CK: p<0.001; K+: p = 0.017). Muscle mitochondrial viability proved to be significantly higher (p = 0.001) and renal function parameters were significantly better (creatinine: p = 0.016; FENa: p<0.001) in the NIM-IR group in comparison to the IR group. Serum TNF-α and IL-6 levels were significantly lower (TNF-α: p = 0.003, IL-6: p = 0.040) as well as W/D ratio and peroxynitrite concentration were significantly lower (p = 0.014; p<0.001) in the NIM-IR group than in the IR group. Conclusion NIM-811 could have the potential of reducing rhabdomyolysis and impairment of the kidney after lower limb IR injury. PMID:24968303

Attenuation of skeletal muscle and renal injury to the lower limb following ischemia-reperfusion using mPTP inhibitor NIM-811.

PubMed

Garbaisz, David; Turoczi, Zsolt; Aranyi, Peter; Fulop, Andras; Rosero, Oliver; Hermesz, Edit; Ferencz, Agnes; Lotz, Gabor; Harsanyi, Laszlo; Szijarto, Attila

2014-01-01

Operation on the infrarenal aorta and large arteries of the lower extremities may cause rhabdomyolysis of the skeletal muscle, which in turn may induce remote kidney injury. NIM-811 (N-metyl-4-isoleucine-cyclosporine) is a mitochondria specific drug, which can prevent ischemic-reperfusion (IR) injury, by inhibiting mitochondrial permeability transition pores (mPTP). Our aim was to reduce damages in the skeletal muscle and the kidney after IR of the lower limb with NIM-811. Wistar rats underwent 180 minutes of bilateral lower limb ischemia and 240 minutes of reperfusion. Four animal groups were formed called Sham (receiving vehicle and sham surgery), NIM-Sham (receiving NIM-811 and sham surgery), IR (receiving vehicle and surgery), and NIM-IR (receiving NIM-811 and surgery). Serum, urine and histological samples were taken at the end of reperfusion. NADH-tetrazolium staining, muscle Wet/Dry (W/D) ratio calculations, laser Doppler-flowmetry (LDF) and mean arterial pressure (MAP) monitoring were performed. Renal peroxynitrite concentration, serum TNF-α and IL-6 levels were measured. Less significant histopathological changes were observable in the NIM-IR group as compared with the IR group. Serum K+ and necroenzyme levels were significantly lower in the NIM-IR group than in the IR group (LDH: p<0.001; CK: p<0.001; K+: p = 0.017). Muscle mitochondrial viability proved to be significantly higher (p = 0.001) and renal function parameters were significantly better (creatinine: p = 0.016; FENa: p<0.001) in the NIM-IR group in comparison to the IR group. Serum TNF-α and IL-6 levels were significantly lower (TNF-α: p = 0.003, IL-6: p = 0.040) as well as W/D ratio and peroxynitrite concentration were significantly lower (p = 0.014; p<0.001) in the NIM-IR group than in the IR group. NIM-811 could have the potential of reducing rhabdomyolysis and impairment of the kidney after lower limb IR injury.

Pretreatment with xenon protected immature rabbit heart from ischaemia/reperfusion injury by opening of the mitoKATP channel.

PubMed

Li, Qian; Lian, Chunwei; Zhou, Ronghua; Li, Tao; Xiang, Xujin; Liu, Bin

2013-04-01

The noble gas anaesthetic, xenon has previously been shown to protect the adult myocardium from ischaemia/reperfusion (I/R) injury, however its effect on immature myocardium is unclear. The aim of this study was to investigate the effect of xenon on the isolated immature heart. Isolated, immature (2-3weeks old) New Zealand rabbit hearts were perfused with Krebs-Henseleit buffer via Langendorff-mode. After 20min of baseline equilibration, hearts were pretreated with 75% xenon, 75% xenon+100μM diazoxide, or 75% xenon+100μM 5-hydroxydecanoate, and then subjected to 1h of global ischaemia and 3h of reperfusion. Pretreatment with 75% xenon significantly improved cardiac function (P<0.01 vs. the I/R group, respectively), limited myocardial infarct size (20.83±2.16%, P<0.01 vs. 35.82±2.14% of the I/R group), reduced cardiac enzyme release (CK-MB, 1.00±0.19IU/L, P<0.01 vs. 0.44±0.14IU/L of the I/R group; LDH, 6.15±1.06IU/L P<0.01 vs. 3.49±0.37IU/L of the I/R group) and decreased apoptosis (6.17±0.56%, P<0.01 vs. 11.31±0.93% of the I/R group). In addition, the mitochondrial structure changes caused by I/R injury were largely prevented by 75% xenon pretreatment (1.37±0.16, P<0.01 vs. 2.32±0.13 of the I/R group). The mitochondrial adenosine triphosphate-sensitive potassium (mitoKATP) channel opener diazoxide did not influence the effect of xenon, but the specific mitoKATP channel blocker 5-hydroxydecanoate completely abolished this effect. Our study demonstrated that pretreatment with 75% xenon protected immature heart from I/R injury, and this protection was probably mediated by preservation of myocardial mitochondria and opening of mitoKATP channel. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Triptolide-induced mitochondrial damage dysregulates fatty acid metabolism in mouse sertoli cells.

PubMed

Cheng, Yisen; Chen, Gaojian; Wang, Li; Kong, Jiamin; Pan, Ji; Xi, Yue; Shen, Feihai; Huang, Zhiying

2018-08-01

Triptolide is a major active ingredient of tripterygium glycosides, used for the therapy of immune and inflammatory diseases. However, its clinical applications are limited by severe male fertility toxicity associated with decreased sperm count, mobility and testicular injures. In this study, we determined that triptoide-induced mitochondrial dysfunction triggered reduction of lactate and dysregulation of fatty acid metabolism in mouse Sertoli cells. First, triptolide induced mitochondrial damage through the suppressing of proliferator-activated receptor coactivator-1 alpha (PGC-1α) activity and protein. Second, mitochondrial damage decreased lactate production and dysregulated fatty acid metabolism. Finally, mitochondrial dysfunction was initiated by the inhibition of sirtuin 1 (SIRT1) with the regulation of AMP-activated protein kinase (AMPK) in Sertoli cells after triptolide treatment. Meanwhile, triptolide induced mitochondrial fatty acid oxidation dysregulation by increasing AMPK phosphorylation. Taken together, we provide evidence that the mechanism of triptolide-induced testicular toxicity under mitochondrial injury may involve a metabolic change. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular identity of cardiac mitochondrial chloride intracellular channel proteins.

PubMed

Ponnalagu, Devasena; Gururaja Rao, Shubha; Farber, Jason; Xin, Wenyu; Hussain, Ahmed Tafsirul; Shah, Kajol; Tanda, Soichi; Berryman, Mark; Edwards, John C; Singh, Harpreet

2016-03-01

Emerging evidences demonstrate significance of chloride channels in cardiac function and cardioprotection from ischemia-reperfusion (IR) injury. Unlike mitochondrial potassium channels sensitive to calcium (BKCa) and ATP (KATP), molecular identity of majority of cardiac mitochondrial chloride channels located at the inner membrane is not known. In this study, we report the presence of unique dimorphic chloride intracellular channel (CLIC) proteins namely CLIC1, CLIC4 and CLIC5 as abundant CLICs in the rodent heart. Further, CLIC4, CLIC5, and an ortholog present in Drosophila (DmCLIC) localize to adult cardiac mitochondria. We found that CLIC4 is enriched in the outer mitochondrial membrane, whereas CLIC5 is present in the inner mitochondrial membrane. Also, CLIC5 plays a direct role in regulating mitochondrial reactive oxygen species (ROS) generation. Our study highlights that CLIC5 is localized to the cardiac mitochondria and directly modulates mitochondrial function. Copyright © 2016 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Early Mitochondrial Adaptations in Skeletal Muscle to Diet-Induced Obesity Are Strain Dependent and Determine Oxidative Stress and Energy Expenditure But Not Insulin Sensitivity

PubMed Central

Sena, Sandra; Sloan, Crystal; Tebbi, Ali; Han, Yong Hwan; O'Neill, Brian T.; Cooksey, Robert C.; Jones, Deborah; Holland, William L.; McClain, Donald A.; Abel, E. Dale

2012-01-01

This study sought to elucidate the relationship between skeletal muscle mitochondrial dysfunction, oxidative stress, and insulin resistance in two mouse models with differential susceptibility to diet-induced obesity. We examined the time course of mitochondrial dysfunction and insulin resistance in obesity-prone C57B and obesity-resistant FVB mouse strains in response to high-fat feeding. After 5 wk, impaired insulin-mediated glucose uptake in skeletal muscle developed in both strains in the absence of any impairment in proximal insulin signaling. Impaired mitochondrial oxidative capacity preceded the development of insulin resistant glucose uptake in C57B mice in concert with increased oxidative stress in skeletal muscle. By contrast, mitochondrial uncoupling in FVB mice, which prevented oxidative stress and increased energy expenditure, did not prevent insulin resistant glucose uptake in skeletal muscle. Preventing oxidative stress in C57B mice treated systemically with an antioxidant normalized skeletal muscle mitochondrial function but failed to normalize glucose tolerance and insulin sensitivity. Furthermore, high fat-fed uncoupling protein 3 knockout mice developed increased oxidative stress that did not worsen glucose tolerance. In the evolution of diet-induced obesity and insulin resistance, initial but divergent strain-dependent mitochondrial adaptations modulate oxidative stress and energy expenditure without influencing the onset of impaired insulin-mediated glucose uptake. PMID:22510273

Lower Susceptibility of Female Mice to Acetaminophen Hepatotoxicity: Role of Mitochondrial Glutathione, Oxidant Stress and c-Jun N-Terminal Kinase

PubMed Central

Du, Kuo; Williams, C. David; McGill, Mitchell R.; Jaeschke, Hartmut

2014-01-01

Acetaminophen (APAP) overdose causes severe hepatotoxicity in animals and humans. However, the mechanisms underlying the gender differences in susceptibility to APAP overdose in mice have not been clarified. In our study, APAP (300 mg/kg) caused severe liver injury in male mice but 69-77% lower injury in females. No gender difference in metabolic activation of APAP was found. Hepatic glutathione (GSH) was rapidly depleted in both genders, while GSH recovery in female mice was 2.6 fold higher in mitochondria at 4h, and 2.5 and 3.3 fold higher in the total liver at 4h and 6h, respectively. This faster recovery of GSH, which correlated with greater induction of glutamate-cysteine ligase, attenuated mitochondrial oxidative stress in female mice, as suggested by a lower GSSG/GSH ratio at 6h (3.8% in males vs. 1.4% in females) and minimal centrilobular nitrotyrosine staining. While c-jun N-terminal kinase (JNK) activation was similar at 2 and 4h post-APAP, it was 3.1 fold lower at 6h in female mice. However, female mice were still protected by the JNK inhibitor SP600125. 17β-Estradiol pretreatment moderately decreased liver injury and oxidative stress in male mice without affecting GSH recovery. Conclusion: The lower susceptibility of female mice is achieved by the improved detoxification of reactive oxygen due to accelerated recovery of mitochondrial GSH levels, which attenuates late JNK activation and liver injury. However, even the reduced injury in female mice was still dependent on JNK. While 17β-estradiol partially protects male mice, it does not affect hepatic GSH recovery. PMID:25218290

Hearts from Mice Fed a Non-Obesogenic High-Fat Diet Exhibit Changes in Their Oxidative State, Calcium and Mitochondria in Parallel with Increased Susceptibility to Reperfusion Injury

PubMed Central

Littlejohns, Ben; Pasdois, Philippe; Duggan, Simon; Bond, Andrew R.; Heesom, Kate; Jackson, Christopher L.; Angelini, Gianni D.; Halestrap, Andrew P.; Suleiman, M.-Saadeh

2014-01-01

Rationale High-fat diet with obesity-associated co-morbidities triggers cardiac remodeling and renders the heart more vulnerable to ischemia/reperfusion injury. However, the effect of high-fat diet without obesity and associated co-morbidities is presently unknown. Objectives To characterize a non-obese mouse model of high-fat diet, assess the vulnerability of hearts to reperfusion injury and to investigate cardiac cellular remodeling in relation to the mechanism(s) underlying reperfusion injury. Methods and Results Feeding C57BL/6J male mice high-fat diet for 20 weeks did not induce obesity, diabetes, cardiac hypertrophy, cardiac dysfunction, atherosclerosis or cardiac apoptosis. However, isolated perfused hearts from mice fed high-fat diet were more vulnerable to reperfusion injury than those from mice fed normal diet. In isolated cardiomyocytes, high-fat diet was associated with higher diastolic intracellular Ca2+ concentration and greater damage to isolated cardiomyocytes following simulated ischemia/reperfusion. High-fat diet was also associated with changes in mitochondrial morphology and expression of some related proteins but not mitochondrial respiration or reactive oxygen species turnover rates. Proteomics, western blot and high-performance liquid chromatography techniques revealed that high-fat diet led to less cardiac oxidative stress, higher catalase expression and significant changes in expression of putative components of the mitochondrial permeability transition pore (mPTP). Inhibition of the mPTP conferred relatively more cardio-protection in the high-fat fed mice compared to normal diet. Conclusions This study shows for the first time that high-fat diet, independent of obesity-induced co-morbidities, triggers changes in cardiac oxidative state, calcium handling and mitochondria which are likely to be responsible for increased vulnerability to cardiac insults. PMID:24950187

Early Effects of Prolonged Cardiac Arrest and Ischemic Postconditioning during Cardiopulmonary Resuscitation on Cardiac and Brain Mitochondrial Function in Pigs.

PubMed

Matsuura, Timothy R; Bartos, Jason A; Tsangaris, Adamantios; Shekar, Kadambari Chandra; Olson, Matthew D; Riess, Matthias L; Bienengraeber, Martin; Aufderheide, Tom P; Neumar, Robert W; Rees, Jennifer N; McKnite, Scott H; Dikalova, Anna E; Dikalov, Sergey I; Douglas, Hunter F; Yannopoulos, Demetris

2017-07-01

Out-of-hospital cardiac arrest (CA) is a prevalent medical crisis resulting in severe injury to the heart and brain and an overall survival of less than 10%. Mitochondrial dysfunction is predicted to be a key determinant of poor outcomes following prolonged CA. However, the onset and severity of mitochondrial dysfunction during CA and cardiopulmonary resuscitation (CPR) is not fully understood. Ischemic postconditioning (IPC), controlled pauses during the initiation of CPR, has been shown to improve cardiac function and neurologically favorable outcomes after 15min of CA. We tested the hypothesis that mitochondrial dysfunction develops during prolonged CA and can be rescued with IPC during CPR (IPC-CPR). A total of 63 swine were randomized to no ischemia (Naïve), 19min of ventricular fibrillation (VF) CA without CPR (Untreated VF), or 15min of CA with 4min of reperfusion with either standard CPR (S-CPR) or IPC-CPR. Mitochondria were isolated from the heart and brain to quantify respiration, rate of ATP synthesis, and calcium retention capacity (CRC). Reactive oxygen species (ROS) production was quantified from fresh frozen heart and brain tissue. Compared to Naïve, Untreated VF induced cardiac and brain ROS overproduction concurrent with decreased mitochondrial respiratory coupling and CRC, as well as decreased cardiac ATP synthesis. Compared to Untreated VF, S-CPR attenuated brain ROS overproduction but had no other effect on mitochondrial function in the heart or brain. Compared to Untreated VF, IPC-CPR improved cardiac mitochondrial respiratory coupling and rate of ATP synthesis, and decreased ROS overproduction in the heart and brain. Fifteen minutes of VF CA results in diminished mitochondrial respiration, ATP synthesis, CRC, and increased ROS production in the heart and brain. IPC-CPR attenuates cardiac mitochondrial dysfunction caused by prolonged VF CA after only 4min of reperfusion, suggesting that IPC-CPR is an effective intervention to reduce cardiac injury. However, reperfusion with both CPR methods had limited effect on mitochondrial function in the brain, emphasizing an important physiological divergence in post-arrest recovery between those two vital organs. Copyright © 2017 Elsevier B.V. All rights reserved.

Inhibition of mitochondrial fragmentation diminishes Huntington’s disease–associated neurodegeneration

PubMed Central

Guo, Xing; Disatnik, Marie-Helene; Monbureau, Marie; Shamloo, Mehrdad; Mochly-Rosen, Daria; Qi, Xin

2013-01-01

Huntington’s disease (HD) is the result of expression of a mutated Huntingtin protein (mtHtt), and is associated with a variety of cellular dysfunctions including excessive mitochondrial fission. Here, we tested whether inhibition of excessive mitochondrial fission prevents mtHtt-induced pathology. We developed a selective inhibitor (P110-TAT) of the mitochondrial fission protein dynamin-related protein 1 (DRP1). We found that P110-TAT inhibited mtHtt-induced excessive mitochondrial fragmentation, improved mitochondrial function, and increased cell viability in HD cell culture models. P110-TAT treatment of fibroblasts from patients with HD and patients with HD with iPS cell–derived neurons reduced mitochondrial fragmentation and corrected mitochondrial dysfunction. P110-TAT treatment also reduced the extent of neurite shortening and cell death in iPS cell–derived neurons in patients with HD. Moreover, treatment of HD transgenic mice with P110-TAT reduced mitochondrial dysfunction, motor deficits, neuropathology, and mortality. We found that p53, a stress gene involved in HD pathogenesis, binds to DRP1 and mediates DRP1-induced mitochondrial and neuronal damage. Furthermore, P110-TAT treatment suppressed mtHtt-induced association of p53 with mitochondria in multiple HD models. These data indicate that inhibition of DRP1-dependent excessive mitochondrial fission with a P110-TAT–like inhibitor may prevent or slow the progression of HD. PMID:24231356

Cardioprotection Via Modulation of Calcium Homeostasis by Thiopental in Hypoxia-Reoxygenated Neonatal Rat Cardiomyocytes

PubMed Central

Kim, Hyun-Soo; Hwang, Ki-Chul

2010-01-01

Purpose Ca2+ homeostasis plays an important role in myocardial cell injury induced by hypoxia-reoxygenation, and prevention of intracellular Ca2+ overload is key to cardioprotection. Even though thiopental is a frequently used anesthetic agent, little is known about its cardioprotective effects, particulary in association with Ca2+ homeostasis. We investigated whether thiopental protects cardiomyocytes against hypoxia-reoxygenation injury by regulating Ca2+ homeostasis. Materials and Methods Neonatal rat cardiomyocytes were isolated. Cardiomyocytes were exposed to different concentrations of thiopental and immediately replaced in the hypoxic chamber to maintain hypoxia. After 1 hour of exposure, a culture dish was transferred to the CO2 incubator and cells were incubated at 37℃ for 5 hours. At the end of the experiments, the authors assessed cell protection using immunoblot analysis and caspase activity. The mRNA of genes involved in Ca2+ homeostasis, mitochondrial membrane potential, and cellular Ca2+ levels were examined. Results In thiopental-treated cardiomyocytes, there was a decrease in expression of the proapoptotic protein Bax, caspase-3 activation, and intracellular Ca2+ content. In addition, both enhancement of anti-apoptotic protein Bcl-2 and activation of Erk concerned with survival were shown. Furthermore, thiopental attenuated alterations of genes involving Ca2+ regulation and significantly modulated abnormal changes of NCX and SERCA2a genes in hypoxia-reoxygenated neonatal cardiomyocytes. Thiopental suppressed disruption of mitochondrial membrane potential (ΔΨm) induced by hypoxia-reoxygenation. Conclusion Thiopental is likely to modulate expression of genes that regulate Ca2+ homeostasis, which reduces apoptotic cell death and results in cardioprotection. PMID:20191008

Mitochondrial DNA Damage Initiates Acute Lung Injury and Multi-Organ System Failure Evoked in Rats by Intra-Tracheal Pseudomonas Aeruginosa.

PubMed

Lee, Yann-Leei; Obiako, Boniface; Gorodnya, Olena M; Ruchko, Mykhaylo V; Kuck, Jamie L; Pastukh, Viktor M; Wilson, Glenn L; Simmons, Jon D; Gillespie, Mark N

2017-07-01

Although studies in rat cultured pulmonary artery endothelial cells, perfused lungs, and intact mice support the concept that oxidative mitochondrial (mt) DNA damage triggers acute lung injury (ALI), it has not yet been determined whether enhanced mtDNA repair forestalls development of ALI and its progression to multiple organ system failure (MOSF). Accordingly, here we examined the effect of a fusion protein construct targeting the DNA glycosylase, Ogg1, to mitochondria in a rat model intra-tracheal Pseudomonas aeruginosa (strain 103; PA103)-induced ALI and MOSF. Relative to controls, animals given PA103 displayed increases in lung vascular filtration coefficient accompanied by transient lung tissue oxidative mtDNA damage and variable changes in mtDNA copy number without evidence of nuclear DNA damage. The approximate 40% of animals surviving 24 h after bacterial administration exhibited multiple organ dysfunction, manifest as increased serum and tissue-specific indices of kidney and liver failure, along with depressed heart rate and blood pressure. While administration of mt-targeted Ogg1 to control animals was innocuous, the active fusion protein, but not a DNA repair-deficient mutant, prevented bacteria-induced increases in lung tissue oxidative mtDNA damage, failed to alter mtDNA copy number, and attenuated lung endothelial barrier degradation. These changes were associated with suppression of liver, kidney, and cardiovascular dysfunction and with decreased 24 h mortality. Collectively, the present findings indicate that oxidative mtDNA damage to lung tissue initiates PA103-induced ALI and MOSF in rats.

Ganoderma atrum polysaccharide ameliorates anoxia/reoxygenation-mediated oxidative stress and apoptosis in human umbilical vein endothelial cells.

PubMed

Zhang, Yan-Song; Li, Wen-Juan; Zhang, Xian-Yi; Yan, Yu-Xin; Nie, Shao-Ping; Gong, De-Ming; Tang, Xiao-Fang; He, Ming; Xie, Ming-Yong

2017-05-01

Ganoderma atrum polysaccharide (PSG-1), a main polysaccharide from Ganoderma atrum, possesses potent antioxidant capacity and cardiovascular benefits. The aim of this study was to investigate the role of PSG-1 in oxidative stress and apoptosis in human umbilical vein endothelial cells (HUVECs) under anoxia/reoxygenation (A/R) injury conditions. The results showed that exposure of HUVECs to A/R triggered cell death and apoptosis. Administration of PSG-1 significantly inhibited A/R-induced cell death and apoptosis in HUVECs. PSG-1-reduced A/R injury was mediated via mitochondrial apoptotic pathway, as evidenced by elevation of mitochondrial Bcl-2 protein and mitochondrial membrane potential, and attenuation of Bax translocation, cytochrome c release and caspases activation. Furthermore, PSG-1 enhanced the activities of superoxide dismutase, catalase and glutathione peroxidase and glutathione content, and concomitantly attenuated reactive oxygen species generation, lipid peroxidation and glutathione disulfide content. The antioxidant, N-acetyl-l-cysteine, significantly ameliorated all of these endothelial injuries caused by A/R, suggesting that antioxidant activities might play a key role in PSG-1-induced endothelial protection. Taken together, these findings suggested that PSG-1 could be as a promising adjuvant against endothelial dysfunction through ameliorating oxidative stress and apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Cranberry flavonoids prevent toxic rat liver mitochondrial damage in vivo and scavenge free radicals in vitro.

PubMed

Lapshina, Elena A; Zamaraeva, Maria; Cheshchevik, Vitali T; Olchowik-Grabarek, Ewa; Sekowski, Szymon; Zukowska, Izabela; Golovach, Nina G; Burd, Vasili N; Zavodnik, Ilya B

2015-06-01

The present study was undertaken for further elucidation of the mechanisms of flavonoid biological activity, focusing on the antioxidative and protective effects of cranberry flavonoids in free radical-generating systems and those on mitochondrial ultrastructure during carbon tetrachloride-induced rat intoxication. Treatment of rats with cranberry flavonoids (7 mg/kg) during chronic carbon tetrachloride-induced intoxication led to prevention of mitochondrial damage, including fragmentation, rupture and local loss of the outer mitochondrial membrane. In radical-generating systems, cranberry flavonoids effectively scavenged nitric oxide (IC50  = 4.4 ± 0.4 µg/ml), superoxide anion radicals (IC50  = 2.8 ± 0.3 µg/ml) and hydroxyl radicals (IC50  = 53 ± 4 µg/ml). The IC50 for reduction of 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) was 2.2 ± 0.3 µg/ml. Flavonoids prevented to some extent lipid peroxidation in liposomal membranes and glutathione oxidation in erythrocytes treated with UV irradiation or organic hydroperoxides as well as decreased the rigidity of the outer leaflet of the liposomal membranes. The hepatoprotective potential of cranberry flavonoids could be due to specific prevention of rat liver mitochondrial damage. The mitochondria-addressed effects of flavonoids might be related both to radical-scavenging properties and modulation of various mitochondrial events. Copyright © 2015 John Wiley & Sons, Ltd.

Protective effect of mitochondrial-targeted antioxidant MitoQ against iron ion 56Fe radiation induced brain injury in mice.

PubMed

Gan, Lu; Wang, Zhenhua; Si, Jing; Zhou, Rong; Sun, Chao; Liu, Yang; Ye, Yancheng; Zhang, Yanshan; Liu, Zhiyuan; Zhang, Hong

2018-02-15

Exposure to iron ion 56 Fe radiation (IR) during space missions poses a significant risk to the central nervous system and radiation exposure is intimately linked to the production of reactive oxygen species (ROS). MitoQ is a mitochondria-targeted antioxidant that has been shown to decrease oxidative damage and lower mitochondrial ROS in a number of animal models. Therefore, the present study aimed to investigate role of the mitochondrial targeted antioxidant MitoQ against 56 Fe particle irradiation-induced oxidative damage and mitochondria dysfunction in the mouse brains. Increased ROS levels were observed in mouse brains after IR compared with the control group. Enhanced ROS production leads to disruption of cellular antioxidant defense systems, mitochondrial respiration dysfunction, altered mitochondria dynamics and increased release of cytochrome c (cyto c) from mitochondria into cytosol resulting in apoptotic cell death. MitoQ reduced IR-induced oxidative stress (decreased ROS production and increased SOD, CAT activities) with decreased lipid peroxidation as well as reduced protein and DNA oxidation. MitoQ also protected mitochondrial respiration after IR. In addition, MitoQ increased the expression of mitofusin2 (Mfn2) and optic atrophy gene1 (OPA1), and decreased the expression of dynamic-like protein (Drp1). MitoQ also suppressed mitochondrial DNA damage, cyto c release, and caspase-3 activity in IR-treated mice compared to the control group. These results demonstrate that MitoQ may protect against IR-induced brain injury. Copyright © 2018 Elsevier Inc. All rights reserved.

Control of mitochondrial physiology and cell death by the Bcl-2 family proteins Bax and Bok.

PubMed

D'Orsi, Beatrice; Mateyka, Julia; Prehn, Jochen H M

2017-10-01

Neuronal cell death is often triggered by events that involve intracellular increases in Ca 2+ . Under resting conditions, the intracellular Ca 2+ concentration is tightly controlled by a number of extrusion and sequestering mechanisms involving the plasma membrane, mitochondria, and ER. These mechanisms act to prevent a disruption of neuronal ion homeostasis. As these processes require ATP, excessive Ca 2+ overloading may cause energy depletion, mitochondrial dysfunction, and may eventually lead to Ca 2+ -dependent cell death. Excessive Ca 2+ entry though glutamate receptors (excitotoxicity) has been implicated in several neurologic and chronic neurodegenerative diseases, including ischemic stroke, epilepsy, and Alzheimer's disease. Recent evidence has revealed that excitotoxic cell death is regulated by the B-cell lymphoma-2 (Bcl-2) family of proteins. Bcl-2 proteins, comprising of both pro-apoptotic and anti-apoptotic members, have been shown to not only mediate the intrinsic apoptosis pathway by controlling mitochondrial outer membrane (MOM) integrity, but to also control neuronal Ca 2+ homeostasis and energetics. In this review, the role of Bcl-2 family proteins in the regulation of apoptosis, their expression in the central nervous system and how they control Ca 2+ -dependent neuronal injury are summarized. We review the current knowledge on Bcl-2 family proteins in the regulation of mitochondrial function and bioenergetics, including the fusion and fission machinery, and their role in Ca 2+ homeostasis regulation at the mitochondria and ER. Specifically, we discuss how the 'pro-apoptotic' Bcl-2 family proteins, Bax and Bok, physiologically expressed in the nervous system, regulate such 'non-apoptotic/daytime' functions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Moderate intensity exercise prevents diabetic cardiomyopathy associated contractile dysfunction through restoration of mitochondrial function and connexin 43 levels in db/db mice.

PubMed

Veeranki, Sudhakar; Givvimani, Srikanth; Kundu, Sourav; Metreveli, Naira; Pushpakumar, Sathnur; Tyagi, Suresh C

2016-03-01

Although the cardiovascular benefits of exercise are well known, exercise induced effects and mechanisms in prevention of cardiomyopathy are less clear during obesity associated type-2 diabetes. The current study assessed the impact of moderate intensity exercise on diabetic cardiomyopathy by examining cardiac function and structure and mitochondrial function. Obese-diabetic (db/db), and lean control (db/+) mice, were subjected to a 5 week, 300 m run on a tread-mill for 5 days/week at the speeds of 10-11 m/min. Various physiological parameters were recorded and the heart function was evaluated with M-mode echocardiography. Contraction parameters and calcium transits were examined on isolated cardiomyocytes. At the molecular level: connexin 43 and 37 (Cx43 and 37) levels, mitochondrial biogenesis regulators: Mfn2 and Drp-1 levels, mitochondrial trans-membrane potential and cytochrome c leakage were assessed through western blotting immunohistochemistry and flow cytometry. Ability of exercise to reverse oxygen consumption rate (OCR), tissue ATP levels, and cardiac fibrosis were also determined. The exercise regimen was able to prevent diabetic cardiac functional deficiencies: ejection fraction (EF) and fractional shortening (FS). Improvements in contraction velocity and contraction maximum were noted with the isolated cardiomyocytes. Restoration of interstitial and micro-vessels associated Cx43 levels and improved gap junction intercellular communication (GJIC) were observed. The decline in the Mfn2/Drp-1 ratio in the db/db mice hearts was prevented after exercise. The exercise regimen further attenuated transmembrane potential decline and cytochrome c leakage. These corrections further led to improvements in OCR and tissue ATP levels and reduction in cardiac fibrosis. Moderate intensity exercise produced significant cardiovascular benefits by improving mitochondrial function through restoration of Cx43 networks and mitochondrial trans-membrane potential and prevention of excessive mitochondrial fission. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trimetazidine prevents palmitate-induced mitochondrial fission and dysfunction in cultured cardiomyocytes.

PubMed

Kuzmicic, Jovan; Parra, Valentina; Verdejo, Hugo E; López-Crisosto, Camila; Chiong, Mario; García, Lorena; Jensen, Michael D; Bernlohr, David A; Castro, Pablo F; Lavandero, Sergio

2014-10-01

Metabolic and cardiovascular disease patients have increased plasma levels of lipids and, specifically, of palmitate, which can be toxic for several tissues. Trimetazidine (TMZ), a partial inhibitor of lipid oxidation, has been proposed as a metabolic modulator for several cardiovascular pathologies. However, its mechanism of action is controversial. Given the fact that TMZ is able to alter mitochondrial metabolism, we evaluated the protective role of TMZ on mitochondrial morphology and function in an in vitro model of lipotoxicity induced by palmitate. We treated cultured rat cardiomyocytes with BSA-conjugated palmitate (25 nM free), TMZ (0.1-100 μM), or a combination of both. We evaluated mitochondrial morphology and lipid accumulation by confocal fluorescence microscopy, parameters of mitochondrial metabolism (mitochondrial membrane potential, oxygen consumption rate [OCR], and ATP levels), and ceramide production by mass spectrometry and indirect immunofluorescence. Palmitate promoted mitochondrial fission evidenced by a decrease in mitochondrial volume (50%) and an increase in the number of mitochondria per cell (80%), whereas TMZ increased mitochondrial volume (39%), and decreased mitochondrial number (56%), suggesting mitochondrial fusion. Palmitate also decreased mitochondrial metabolism (ATP levels and OCR), while TMZ potentiated all the metabolic parameters assessed. Moreover, pretreatment with TMZ protected the cardiomyocytes from palmitate-induced mitochondrial fission and dysfunction. TMZ also increased lipid accumulation in cardiomyocytes, and prevented palmitate-induced ceramide production. Our data show that TMZ protects cardiomyocytes by changing intracellular lipid management. Thus, the beneficial effects of TMZ on patients with different cardiovascular pathologies can be related to modulation of the mitochondrial morphology and function. Copyright © 2014 Elsevier Inc. All rights reserved.

Preventing Mitochondrial Diseases: Embryo-Sparing Donor-Independent Options.

PubMed

Adashi, Eli Y; Cohen, I Glenn

2018-05-01

Mutant mitochondrial DNA gives rise to a broad range of incurable inborn maladies. Prevention may now be possible by replacing the mutation-carrying mitochondria of zygotes or oocytes at risk with donated unaffected counterparts. However, mitochondrial replacement therapy is being held back by theological, ethical, and safety concerns over the loss of human zygotes and the involvement of a donor. These concerns make it plain that the identification, validation, and regulatory adjudication of novel embryo-sparing donor-independent technologies remains a pressing imperative. This Opinion highlights three emerging embryo-sparing donor-independent options that stand to markedly allay theological, ethical, and safety concerns raised by mitochondrial replacement therapy. Copyright © 2018 Elsevier Ltd. All rights reserved.

Salvaging hope: Is increasing NAD(+) a key to treating mitochondrial myopathy?

PubMed

Lightowlers, Robert N; Chrzanowska-Lightowlers, Zofia M A

2014-06-01

Mitochondrial diseases can arise from mutations either in mitochondrial DNA or in nuclear DNA encoding mitochondrially destined proteins. Currently, there is no cure for these diseases although treatments to ameliorate a subset of the symptoms are being developed. In this issue of EMBO Molecular Medicine, Khan et al (2014) use a mouse model to test the efficacy of a simple dietary supplement of nicotinamide riboside to treat and prevent mitochondrial myopathies.

NCIPC's contribution to global injury and violence prevention: past, present, and future.

PubMed

Mahendra, Reshma R; Roehler, Douglas R; Degutis, Linda C

2012-09-01

Injuries and violence impact millions across the globe each year. For the past 20 years, the National Center for Injury Prevention and Control (NCIPC) at the Centers for Disease Control and Prevention (CDC) has assembled the largest cadre of injury and violence prevention experts in the world to reduce the burden of injuries and violence domestically and to inform global injury and violence prevention efforts. This article focuses on NCIPC's global injury and violence prevention work that involves: increasing awareness of the preventability of injury and violence, partnerships to promote injury research and best practices; establishing standards and guidance for data collection; building capacity through training and mentoring; and supporting evidence-based strategies. To decrease the global burden, the authors propose priority setting to maximize the development and sustainability of financial and human resources for injury and violence prevention. The authors call for increased capacity and resources for global injury and violence prevention. Published by Elsevier Ltd.

Behaviour, the key factor for sports injury prevention.

PubMed

Verhagen, Evert A L M; van Stralen, Maartje M; van Mechelen, Willem

2010-11-01

Safety in sports and physical activity is an important prerequisite for continuing participation in sports, as well as for maintenance of a healthy physically active lifestyle. For this reason, prevention, reduction and control of sports injuries are important goals for society as a whole. Recent advances in sports medicine discuss the need for research on real-life injury prevention. Such views call for a more behavioural approach when it comes to actual sports injury prevention. Nevertheless, the role of behaviour in sports injury prevention remains under-researched. In order to push the field of sports injury prevention forward, this article provides an overview of the relationship between behaviour and sports injury risk. Different types of behaviour relate to injury risk factors and injury mechanisms. Behaviour that influences risk factors and injury mechanisms is not confined only to the athlete. Various types of behaviour by, for example, the coach, referee, physical therapist or sports associations, also influence risk factors and injury mechanisms. In addition, multiple behaviours often act together. Some types of behaviour may directly affect injury risk and are by definition a risk factor. Other behaviours may only affect risk factors and injury mechanisms, and influence injury risk indirectly. Recent ideas on injury prevention that call for studies on real-life injury prevention still rely heavily on preventive measures that are established through efficacy research. A serious limitation in such an approach is that one expects that proven preventive measures will be adopted if the determinants and influences of sports safety behaviours are understood. Therefore, if one truly wants to prevent sports injuries in a real-life situation, a broader research focus is needed. In trying to do so, we need to look at lessons learned from other fields of injury prevention research.

Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis.

PubMed

de Graaf, Aniek O; van den Heuvel, Lambert P; Dijkman, Henry B P M; de Abreu, Ronney A; Birkenkamp, Kim U; de Witte, Theo; van der Reijden, Bert A; Smeitink, Jan A M; Jansen, Joop H

2004-10-01

Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity.

Mitochondrial metals as a potential therapeutic target in neurodegeneration

PubMed Central

Grubman, A; White, A R; Liddell, J R

2014-01-01

Transition metals are critical for enzyme function and protein folding, but in excess can mediate neurotoxic oxidative processes. As mitochondria are particularly vulnerable to oxidative damage due to radicals generated during ATP production, mitochondrial biometal homeostasis must therefore be tightly controlled to safely harness the redox potential of metal enzyme cofactors. Dysregulation of metal functions is evident in numerous neurological disorders including Alzheimer's disease, stroke, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and Friedrich's ataxia. This review describes the mitochondrial metal defects in these disorders and highlights novel metal-based therapeutic approaches that target mitochondrial metal homeostasis in neurological disorders. Linked Articles This article is part of a themed issue on Mitochondrial Pharmacology: Energy, Injury & Beyond. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2014.171.issue-8 PMID:24206195

Mitochondrial functions of RECQL4 are required for the prevention of aerobic glycolysis-dependent cell invasion.

PubMed

Kumari, Jyoti; Hussain, Mansoor; De, Siddharth; Chandra, Suruchika; Modi, Priyanka; Tikoo, Shweta; Singh, Archana; Sagar, Chandrasekhar; Sepuri, Naresh Babu V; Sengupta, Sagar

2016-04-01

Germline mutations in RECQL4 helicase are associated with Rothmund-Thomson syndrome, which is characterized by a predisposition to cancer. RECQL4 localizes to the mitochondria, where it acts as an accessory factor during mitochondrial DNA replication. To understand the specific mitochondrial functions of RECQL4, we created isogenic cell lines, in which the mitochondrial localization of the helicase was either retained or abolished. The mitochondrial integrity was affected due to the absence of RECQL4 in mitochondria, leading to a decrease in F1F0-ATP synthase activity. In cells where RECQL4 does not localize to mitochondria, the membrane potential was decreased, whereas ROS levels increased due to the presence of high levels of catalytically inactive SOD2. Inactive SOD2 accumulated owing to diminished SIRT3 activity. Lack of the mitochondrial functions of RECQL4 led to aerobic glycolysis that, in turn, led to an increased invasive capability within these cells. Together, this study demonstrates for the first time that, owing to its mitochondrial functions, the accessory mitochondrial replication helicase RECQL4 prevents the invasive step in the neoplastic transformation process. © 2016. Published by The Company of Biologists Ltd.

Optical metabolic imaging of irradiated rat heart exposed to ischemia-reperfusion injury

NASA Astrophysics Data System (ADS)

la Cour, Mette Funding; Mehrvar, Shima; Heisner, James S.; Motlagh, Mohammad Masoudi; Medhora, Meetha; Ranji, Mahsa; Camara, Amadou K. S.

2018-01-01

Whole thoracic irradiation (WTI) is known to cause deterioration in cardiac function. Whether irradiation predisposes the heart to further ischemia and reperfusion (IR) injury is not well known. The aim of this study is to examine the susceptibility of rat hearts to IR injury following a single fraction of 15 Gy WTI and to investigate the role of mitochondrial metabolism in the differential susceptibility to IR injury. After day 35 of irradiation, ex vivo hearts from irradiated and nonirradiated rats (controls) were exposed to 25-min global ischemia followed by 60-min IR, or hearts were perfused without IR for the same protocol duration [time controls (TC)]. Online fluorometry of metabolic indices [redox state: reduced nicotinamide adenine dinucleotide (NADH), oxidized flavin adenine dinucleotide (FAD), and NADH/FAD redox ratio] and functional variables [systolic left ventricular pressure (LVP), diastolic LVP (diaLVP), coronary flow (CF), and heart rate were recorded in the beating heart; developed LVP (dLVP) and rate pressure product (RPP)] were derived. At the end of each experimental protocol, hearts were immediately snap frozen in liquid N2 for later three-dimensional imaging of the mitochondrial redox state using optical cryoimaging. Irradiation caused a delay in recovery of dLVP and RPP after IR when compared to nonirradiated hearts but recovered to the same level at the end of reperfusion. CF in the irradiated hearts recovered better than the control hearts after IR injury. Both fluorometry and 3-D cryoimaging showed that in WTI and control hearts, the redox ratio increased during ischemia (reduced) and decreased on reperfusion (oxidized) when compared to their respective TCs; however, there was no significant difference in the redox state between WTI and controls. In conclusion, our results show that although irradiation of rat hearts compromised baseline cardiovascular function, it did not alter cardiac mitochondrial redox state and induce greater susceptibility of these hearts to IR injury.

Mitochondrial translocation of Nur77 induced by ROS contributed to cardiomyocyte apoptosis in metabolic syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Aibin; Liu, Jingyi; Institute of Cardiovascular Disease, General Hospital of Beijing Command, PLA, Beijing

Highlights: • Metabolic syndrome exacerbated MI/R induced injury accompanied by decreased Nur77. • ROS led to Nur77 translocation in metabolic syndrome. • Inhibiting relocation of Nur77 to mitochondria reduced ROS-induced cardiomyocyte injury in metabolic syndrome. - Abstract: Metabolic syndrome is a major risk factor for cardiovascular diseases, and increased cardiomyocyte apoptosis which contributes to cardiac dysfunction after myocardial ischemia/reperfusion (MI/R) injury. Nur77, a nuclear orphan receptor, is involved in such various cellular events as apoptosis, proliferation, and glucose and lipid metabolism in several cell types. Apoptosis is positively correlated with mitochondrial translocation of Nur77 in the cancer cells. However, themore » roles of Nur77 on cardiac myocytes in patients with metabolic syndrome remain unclear. The objective of this study was to determine whether Nur77 may contribute to cardiac apoptosis in patients with metabolic syndrome after I/R injury, and, if so, to identify the underlying molecular mechanisms responsible. We used leptin-deficient (ob/ob) mice to make metabolic syndrome models. In this report, we observed that, accompanied by the substantial decline in apoptosis inducer Nur77, MI/R induced cardiac dysfunction was manifested as cardiomyopathy and increased ROS. Using the neonatal rat cardiac myocytes cultured in a high-glucose and high-fat medium, we found that excessive H{sub 2}O{sub 2} led to the significant alteration in mitochondrial membrane potential and translocation of Nur77 from the nucleus to the mitochondria. However, inhibition of the relocation of Nur77 to mitochondria via Cyclosporin A reversed the changes in membrane potential mediated by H{sub 2}O{sub 2} and reduced myocardial cell injury. Therefore, these data provide a potential underlying mechanism for cardiac dysfunction in metabolic syndrome and the suppression of Nur77 translocation may provide an effective approach to reduce cardiac injury in the process.« less

Protective effects of a natural product, curcumin, against amyloid β induced mitochondrial and synaptic toxicities in Alzheimer's disease

PubMed Central

Reddy, P Hemachandra; Manczak, Maria; Yin, Xiangling; Grady, Mary Catharine; Mitchell, Andrew; Kandimalla, Ramesh; Kuruva, Chandra Sekhar

2016-01-01

The purpose of our study was to investigate the protective effects of a natural product—‘curcumin’— in Alzheimer's disease (AD)-like neurons. Although much research has been done in AD, very little has been reported on the effects of curcumin on mitochondrial biogenesis, dynamics, function and synaptic activities. Therefore, the present study investigated the protective effects against amyloid β (Aβ) induced mitochondrial and synaptic toxicities. Using human neuroblastoma (SHSY5Y) cells, curcumin and Aβ, we studied the protective effects of curcumin against Aβ. Further, we also studied preventive (curcumin+Aβ) and intervention (Aβ+curcumin) effects of curcumin against Aβ in SHSY5Y cells. Using real time RT-PCR, immunoblotting and immunofluorescence analysis, we measured mRNA and protein levels of mitochondrial dynamics, mitochondrial biogenesis and synaptic genes. We also assessed mitochondrial function by measuring hydrogen peroxide, lipid peroxidation, cytochrome oxidase activity and mitochondrial ATP. Cell viability was studied using the MTT assay. Aβ was found to impair mitochondrial dynamics, reduce mitochondrial biogenesis and decrease synaptic activity and mitochondrial function. In contrast, curcumin enhanced mitochondrial fusion activity and reduced fission machinery, and increased biogenesis and synaptic proteins. Mitochondrial function and cell viability were elevated in curcumin treated cells. Interestingly, curcumin pre- and post-treated cells incubated with Aβ showed reduced mitochondrial dysfunction, and maintained cell viability and mitochondrial dynamics, mitochondrial biogenesis and synaptic activity. Further, the protective effects of curcumin were stronger in pretreated SHSY5Y cells than in post-treated cells, indicating that curcumin works better in prevention than treatment in AD-like neurons. Our findings suggest that curcumin is a promising drug molecule to treat AD patients. PMID:27521081

Protective effects of a natural product, curcumin, against amyloid β induced mitochondrial and synaptic toxicities in Alzheimer's disease.

PubMed

Reddy, P Hemachandra; Manczak, Maria; Yin, Xiangling; Grady, Mary Catharine; Mitchell, Andrew; Kandimalla, Ramesh; Kuruva, Chandra Sekhar

2016-12-01

The purpose of our study was to investigate the protective effects of a natural product-'curcumin'- in Alzheimer's disease (AD)-like neurons. Although much research has been done in AD, very little has been reported on the effects of curcumin on mitochondrial biogenesis, dynamics, function and synaptic activities. Therefore, the present study investigated the protective effects against amyloid β (Aβ) induced mitochondrial and synaptic toxicities. Using human neuroblastoma (SHSY5Y) cells, curcumin and Aβ, we studied the protective effects of curcumin against Aβ. Further, we also studied preventive (curcumin+Aβ) and intervention (Aβ+curcumin) effects of curcumin against Aβ in SHSY5Y cells. Using real time RT-PCR, immunoblotting and immunofluorescence analysis, we measured mRNA and protein levels of mitochondrial dynamics, mitochondrial biogenesis and synaptic genes. We also assessed mitochondrial function by measuring hydrogen peroxide, lipid peroxidation, cytochrome oxidase activity and mitochondrial ATP. Cell viability was studied using the MTT assay. Aβ was found to impair mitochondrial dynamics, reduce mitochondrial biogenesis and decrease synaptic activity and mitochondrial function. In contrast, curcumin enhanced mitochondrial fusion activity and reduced fission machinery, and increased biogenesis and synaptic proteins. Mitochondrial function and cell viability were elevated in curcumin treated cells. Interestingly, curcumin pre- and post-treated cells incubated with Aβ showed reduced mitochondrial dysfunction, and maintained cell viability and mitochondrial dynamics, mitochondrial biogenesis and synaptic activity. Further, the protective effects of curcumin were stronger in pretreated SHSY5Y cells than in post-treated cells, indicating that curcumin works better in prevention than treatment in AD-like neurons. Our findings suggest that curcumin is a promising drug molecule to treat AD patients. Copyright © 2016 American Federation for Medical Research.

Mitochondria-Division Inhibitor 1 Protects Against Amyloid-β induced Mitochondrial Fragmentation and Synaptic Damage in Alzheimer's Disease.

PubMed

Reddy, P Hemachandra; Manczak, Maria; Yin, XiangLing

2017-01-01

The purpose our study was to determine the protective effects of mitochondria division inhibitor 1 (Mdivi1) in Alzheimer's disease (AD). Mdivi1 is hypothesized to reduce excessive fragmentation of mitochondria and mitochondrial dysfunction in AD neurons. Very little is known about whether Mdivi1 can confer protective effects in AD. In the present study, we sought to determine the protective effects of Mdivi1 against amyloid-β (Aβ)- and mitochondrial fission protein, dynamin-related protein 1 (Drp1)-induced excessive fragmentation of mitochondria in AD progression. We also studied preventive (Mdivi1+Aβ42) and intervention (Aβ42+Mdivi1) effects against Aβ42 in N2a cells. Using real-time RT-PCR and immunoblotting analysis, we measured mRNA and protein levels of mitochondrial dynamics, mitochondrial biogenesis, and synaptic genes. We also assessed mitochondrial function by measuring H2O2, lipid peroxidation, cytochrome oxidase activity, and mitochondrial ATP. MTT assays were used to assess the cell viability. Aβ42 was found to impair mitochondrial dynamics, lower mitochondrial biogenesis, lower synaptic activity, and lower mitochondrial function. On the contrary, Mdivi1 enhanced mitochondrial fusion activity, lowered fission machinery, and increased biogenesis and synaptic proteins. Mitochondrial function and cell viability were elevated in Mdivi1-treated cells. Interestingly, Mdivi1 pre- and post-treated cells treated with Aβ showed reduced mitochondrial dysfunction, and maintained cell viability, mitochondrial dynamics, mitochondrial biogenesis, and synaptic activity. The protective effects of Mdivi1 were stronger in N2a+Aβ42 pre-treated with Mdivi1, than in N2a+Aβ42 cells than Mdivi1 post-treated cells, indicating that Mdivi1 works better in prevention than treatment in AD like neurons.

Telmisartan enhances mitochondrial activity and alters cellular functions in human coronary artery endothelial cells via AMP-activated protein kinase pathway.

PubMed

Kurokawa, Hirofumi; Sugiyama, Seigo; Nozaki, Toshimitsu; Sugamura, Koichi; Toyama, Kensuke; Matsubara, Junichi; Fujisue, Koichiro; Ohba, Keisuke; Maeda, Hirofumi; Konishi, Masaaki; Akiyama, Eiichi; Sumida, Hitoshi; Izumiya, Yasuhiro; Yasuda, Osamu; Kim-Mitsuyama, Shokei; Ogawa, Hisao

2015-04-01

Mitochondrial dysfunction plays an important role in cellular senescence and impaired function of vascular endothelium, resulted in cardiovascular diseases. Telmisartan is a unique angiotensin II type I receptor blocker that has been shown to prevent cardiovascular events in high risk patients. AMP-activated protein kinase (AMPK) plays a critical role in mitochondrial biogenesis and endothelial function. This study assessed whether telmisartan enhances mitochondrial function and alters cellular functions via AMPK in human coronary artery endothelial cells (HCAECs). In cultured HCAECs, telmisartan significantly enhanced mitochondrial activity assessed by mitochondrial reductase activity and intracellular ATP production and increased the expression of mitochondria related genes. Telmisartan prevented cellular senescence and exhibited the anti-apoptotic and pro-angiogenic properties. The expression of genes related anti-oxidant and pro-angiogenic properties were increased by telmisartan. Telmisartan increased endothelial NO synthase and AMPK phosphorylation. Peroxisome proliferator-activated receptor gamma signaling was not involved in telmisartan-induced improvement of mitochondrial function. All of these effects were abolished by inhibition of AMPK. Telmisartan enhanced mitochondrial activity and exhibited anti-senescence effects and improving endothelial function through AMPK in HCAECs. Telmisartan could provide beneficial effects on vascular diseases via enhancement of mitochondrial activity and modulating endothelial function through AMPK activation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Naringin ameliorates gentamicin-induced nephrotoxicity and associated mitochondrial dysfunction, apoptosis and inflammation in rats: Possible mechanism of nephroprotection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahu, Bidya Dhar; Tatireddy, Srujana; Koneru, Meghana

Gentamicin-induced nephrotoxicity has been well documented, although its underlying mechanisms and preventive strategies remain to be investigated. The present study was designed to investigate the protective effect of naringin, a bioflavonoid, on gentamicin-induced nephrotoxicity and to elucidate the potential mechanism. Serum specific renal function parameters (blood urea nitrogen and creatinine) and histopathology of kidney tissues were evaluated to assess the gentamicin-induced nephrotoxicity. Renal oxidative stress (lipid peroxidation, protein carbonylation, enzymatic and non-enzymatic antioxidants), inflammatory (NF-kB [p65], TNF-α, IL-6 and MPO) and apoptotic (caspase 3, caspase 9, Bax, Bcl-2, p53 and DNA fragmentation) markers were also evaluated. Significant decrease in mitochondrialmore » NADH dehydrogenase, succinate dehydrogenase, cytochrome c oxidase and mitochondrial redox activity indicated the gentamicin-induced mitochondrial dysfunction. Naringin (100 mg/kg) treatment along with gentamicin restored the mitochondrial function and increased the renal endogenous antioxidant status. Gentamicin induced increased renal inflammatory cytokines (TNF-α and IL-6), nuclear protein expression of NF-κB (p65) and NF-κB-DNA binding activity and myeloperoxidase (MPO) activity were significantly decreased upon naringin treatment. In addition, naringin treatment significantly decreased the amount of cleaved caspase 3, Bax, and p53 protein expression and increased the Bcl-2 protein expression. Naringin treatment also ameliorated the extent of histologic injury and reduced inflammatory infiltration in renal tubules. U-HPLS-MS data revealed that naringin co-administration along with gentamicin did not alter the renal uptake and/or accumulation of gentamicin in kidney tissues. These findings suggest that naringin treatment attenuates renal dysfunction and structural damage through the reduction of oxidative stress, mitochondrial dysfunction, inflammation and apoptosis in the kidney. - Highlights: • Naringin ameliorated gentamicin-induced nephrotoxicity in rats. • Naringin treatment attenuated gentamicin-induced renal apoptosis in rats. • Naringin ameliorated gentamicin-induced renal mitochondrial dysfunction in rats. • Naringin decreased NF-κB activation and pro-inflammatory cytokine release. • U-HPLC-MS data revealed that naringin did not alter the renal uptake of gentamicin.« less

Overexpression of the long noncoding RNA TUG1 protects against cold-induced injury of mouse livers by inhibiting apoptosis and inflammation.

PubMed

Su, Song; Liu, Jiang; He, Kai; Zhang, Mengyu; Feng, Chunhong; Peng, Fangyi; Li, Bo; Xia, Xianming

2016-04-01

Hepatic injury provoked by cold storage is a major problem affecting liver transplantation, as exposure to cold induces apoptosis in hepatic tissues. Long noncoding RNAs (lncRNAs) are increasingly understood to regulate apoptosis, but the contribution of lncRNAs to cold-induced liver injury remains unknown. Using RNA-seq, we determined the differential lncRNA expression profile in mouse livers after cold storage and found that expression of the lncRNA TUG1 was significantly down-regulated. Overexpression of TUG1 attenuated cold-induced apoptosis in mouse hepatocytes and liver sinusoidal endothelial cells LSECs, in part by blocking mitochondrial apoptosis and endoplasmic reticulum (ER) stress pathways. Moreover, TUG1 attenuated apoptosis, inflammation, and oxidative stress in vivo in livers subjected to cold storage. Overexpression of TUG1 also improved hepatocyte function and prolonged hepatic graft survival rates in mice. These results suggest that the lncRNA TUG1 exerts a protective effect against cold-induced liver damage by inhibiting apoptosis in mice, and suggests a potential role for TUG1 as a target for the prevention of cold-induced liver damage in liver transplantation. RNA-seq data are available from GEO using accession number GSE76609. © 2016 Federation of European Biochemical Societies.

Salvaging hope: Is increasing NAD+ a key to treating mitochondrial myopathy?

PubMed Central

Lightowlers, Robert N; Chrzanowska-Lightowlers, Zofia MA

2014-01-01

Mitochondrial diseases can arise from mutations either in mitochondrial DNA or in nuclear DNA encoding mitochondrially destined proteins. Currently, there is no cure for these diseases although treatments to ameliorate a subset of the symptoms are being developed. In this issue of EMBO Molecular Medicine, Khan et al (2014) use a mouse model to test the efficacy of a simple dietary supplement of nicotinamide riboside to treat and prevent mitochondrial myopathies. PMID:24838280

Patient participation in pressure injury prevention: giving patient's a voice.

PubMed

Latimer, Sharon; Chaboyer, Wendy; Gillespie, Brigid

2014-12-01

Pressure injuries burden patients and healthcare organisations, with some preventative practices having little impact on prevalence reduction. Patient participation in care may be an effective pressure injury prevention strategy, yet patient preferences are unknown. The aim of this interpretive study was to describe patients' perceptions of their current and future role in pressure injury prevention. Semi-structured interviews were conducted with 20 adult inpatients recruited from four medical units, at two Australian metropolitan hospitals. Interview data were analysed using content analysis, with three categories emerging: 'experiencing pressure injuries'; 'participating in pressure injury prevention'; and 'resourcing pressure injury prevention and treatment'. These categories reflect the complex nature of participants' pressure injury experience. The findings suggest participants gather pressure injury knowledge from first-hand and vicarious experience; knowledge they bring to hospital. Most participants preferred a proactive pressure injury prevention role. Many identified barriers in the healthcare environment that impeded their participation and affected their experience of pressure injuries and pressure injury prevention. If patient participation as a pressure injury prevention strategy is to be considered, nurses and organisations need to view patients as partners. © 2013 Nordic College of Caring Science.

Plasma bacterial and mitochondrial DNA distinguish bacterial sepsis from sterile systemic inflammatory response syndrome and quantify inflammatory tissue injury in nonhuman primates.

PubMed

Sursal, Tolga; Stearns-Kurosawa, Deborah J; Itagaki, Kiyoshi; Oh, Sun-Young; Sun, Shiqin; Kurosawa, Shinichiro; Hauser, Carl J

2013-01-01

Systemic inflammatory response syndrome (SIRS) is a fundamental host response common to bacterial infection and sterile tissue injury. Systemic inflammatory response syndrome can cause organ dysfunction and death, but its mechanisms are incompletely understood. Moreover, SIRS can progress to organ failure or death despite being sterile or after control of the inciting infection. Biomarkers discriminating between sepsis, sterile SIRS, and postinfective SIRS would therefore help direct care. Circulating mitochondrial DNA (mtDNA) is a damage-associated molecular pattern reflecting cellular injury. Circulating bacterial 16S DNA (bDNA) is a pathogen-associated pattern (PAMP) reflecting ongoing infection. We developed quantitative polymerase chain reaction assays to quantify these markers, and predicting their plasma levels might help distinguish sterile injury from infection. To study these events in primates, we assayed banked serum from Papio baboons that had undergone a brief challenge of intravenous Bacillus anthracis delta Sterne (modified to remove toxins) followed by antibiotics (anthrax) that causes organ failure and death. To investigate the progression of sepsis to "severe" sepsis and death, we studied animals where anthrax was pretreated with drotrecogin alfa (activated protein C), which attenuates sepsis in baboons. We also contrasted lethal anthrax bacteremia against nonlethal E. coli bacteremia and against sterile tissue injury from Shiga-like toxin 1. Bacterial DNA and mtDNA levels in timed samples were correlated with blood culture results and assays of organ function. Sterile injury by Shiga-like toxin 1 increased mtDNA, but bDNA was undetectable: consistent with the absence of infection. The bacterial challenges caused parallel early bDNA and mtDNA increases, but bDNA detected pathogens even after bacteria were undetectable by culture. Sublethal E. coli challenge only caused transient rises in mtDNA consistent with a self-limited injury. In lethal anthrax challenge (n = 4), bDNA increased transiently, but mtDNA levels remained elevated until death, consistent with persistent septic tissue damage after bacterial clearance. Critically, activated protein C pretreatment (n = 4) allowed mtDNA levels to decay after bacterial clearance with sparing of organ function and survival. In summary, host tissue injury correlates with mtDNA whether infective or sterile. Mitochondrial DNA and bDNA polymerase chain reactions can quantify tissue injury incurred by septic or sterile mechanisms and suggest the source of SIRS of unknown origin.

Inhibition of autophagy promotes CYP2E1-dependent toxicity in HepG2 cells via elevated oxidative stress, mitochondria dysfunction and activation of p38 and JNK MAPK☆

PubMed Central

Wu, Defeng; Cederbaum, Arthur I.

2013-01-01

Autophagy has been shown to be protective against drug and alcohol-induced liver injury. CYP2E1 plays a role in the toxicity of ethanol, carcinogens and certain drugs. Inhibition of autophagy increased ethanol-toxicity and accumulation of fat in wild type and CYP2E1 knockin mice but not in CYP2E1 knockout mice as well as in HepG2 cells expressing CYP2E1 (E47 cells) but not HepG2 cells lacking CYP2E1 (C34 cells). The goal of the current study was to evaluate whether modulation of autophagy can affect CYP2E1-dependent cytotoxicity in the E47 cells. The agents used to promote CYP2E1 –dependent toxicity were a polyunsaturated fatty acid, arachidonic acid (AA), buthionine sulfoximine (BSO), which depletes GSH, and CCl4, which is metabolized to the CCl3 radical. These three agents produced a decrease in E47 cell viability which was enhanced upon inhibition of autophagy by 3-methyladenine (3-MA) or Atg 7 siRNA. Toxicity was lowered by rapamycin which increased autophagy and was much lower to the C34 cells which do not express CYP2E1. Toxicity was mainly necrotic and was associated with an increase in reactive oxygen production and oxidative stress; 3-MA increased while rapamycin blunted the oxidative stress. The enhanced toxicity and ROS formation produced when autophagy was inhibited was prevented by the antioxidant N-Acetyl cysteine. AA, BSO and CCl4 produced mitochondrial dysfunction, lowered cellular ATP levels and elevated mitochondrial production of ROS. This mitochondrial dysfunction was enhanced by inhibition of autophagy with 3-MA but decreased when autophagy was increased by rapamycin. The mitogen activated protein kinases p38 MAPK and JNK were activated by AA especially when autophagy was inhibited and chemical inhibitors of p38 MAPK and JNK lowered the elevated toxicity of AA produced by 3-MA. These results show that autophagy was protective against the toxicity produced by several agents known to be activated by CYP2E1. Since CYP2E1 plays an important role in the toxicity of ethanol, drugs and carcinogens and is activated under various pathophysiological conditions such as diabetes, NASH and obesity, attempts to stimulate autophagy may be beneficial in preventing/lowering CYP2E1/ethanol liver injury. PMID:24273738

Mitochondrial Redox Signaling and Tumor Progression.

PubMed

Chen, Yuxin; Zhang, Haiqing; Zhou, Huanjiao Jenny; Ji, Weidong; Min, Wang

2016-03-25

Cancer cell can reprogram their energy production by switching mitochondrial oxidative phosphorylation to glycolysis. However, mitochondria play multiple roles in cancer cells, including redox regulation, reactive oxygen species (ROS) generation, and apoptotic signaling. Moreover, these mitochondrial roles are integrated via multiple interconnected metabolic and redox sensitive pathways. Interestingly, mitochondrial redox proteins biphasically regulate tumor progression depending on cellular ROS levels. Low level of ROS functions as signaling messengers promoting cancer cell proliferation and cancer invasion. However, anti-cancer drug-initiated stress signaling could induce excessive ROS, which is detrimental to cancer cells. Mitochondrial redox proteins could scavenger basal ROS and function as "tumor suppressors" or prevent excessive ROS to act as "tumor promoter". Paradoxically, excessive ROS often also induce DNA mutations and/or promotes tumor metastasis at various stages of cancer progression. Targeting redox-sensitive pathways and transcriptional factors in the appropriate context offers great promise for cancer prevention and therapy. However, the therapeutics should be cancer-type and stage-dependent.

Leptin, Insulin, and Cinnamon Polyphenols Attenuate Glial Swelling and Mitochondrial Dysfunction in Ischemic Injury

USDA-ARS?s Scientific Manuscript database

Obesity is a major risk factor for stroke, and tissue injury following a stroke may be more severe in the obese. A key feature of obesity is increased serum levels of obesity-related hormones including leptin and insulin, indicating a state of resistance to these hormones. Insulin resistance is gen...

Protective effects of cassia seed ethanol extract against carbon tetrachloride-induced liver injury in mice.

PubMed

Xie, Qing; Guo, Fang-Fang; Zhou, Wen

2012-01-01

Oxidative stress has been recognized as a critical pathogenetic mechanism for the initiation and the progression of hepatic injury in a variety of liver disorders. Antioxidants, including many natural compounds or extracts, have been used to cope with liver disorders. The present study was designed to investigate the hepatoprotective effects of cassia seed ethanol extract (CSE) in carbon tetrachloride (CCl(4))-induced liver injury in mice. The animals were pre-treated with different doses of CSE (0.5, 1.0, 2.0 g/kg body weight) or distilled water for 5 days, then were injected intraperitoneally with CCl(4) (0.1% in corn oil, v/v, 20 ml/kg body weight), and sacrificed at 16 hours after CCl(4) exposure. The serum aminotransferase activities, histopathological changes, hepatic and mitochondrial antioxidant indexes, and cytochrome P450 2E1 (CYP2E1) activities were examined. Consistent with previous studies, acute CCl(4) administration caused great lesion to the liver, shown by the elevation of the serum aminotransferase activities, mitochondria membrane permeability transition (MPT), and the ballooning degeneration of hepatocytes. However, these adverse effects were all significantly inhibited by CSE pretreatment. CCl(4)-induced decrease of the CYP2E1 activity was dose-dependently inhibited by CSE pretreatment. Furthermore, CSE dramatically decreased the hepatic and mitochondrial malondialdehyde (MDA) levels, increased the hepatic and mitochondrial glutathione (GSH) levels, and restored the activities of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione S-transferase (GST). These results suggested that CSE could protect mice against CCl(4)-induced liver injury via enhancement of the antioxidant capacity.

Fusion or Fission: The Destiny of Mitochondria In Traumatic Brain Injury of Different Severities.

PubMed

Di Pietro, Valentina; Lazzarino, Giacomo; Amorini, Angela Maria; Signoretti, Stefano; Hill, Lisa J; Porto, Edoardo; Tavazzi, Barbara; Lazzarino, Giuseppe; Belli, Antonio

2017-08-23

Mitochondrial dynamics are regulated by a complex system of proteins representing the mitochondrial quality control (MQC). MQC balances antagonistic forces of fusion and fission determining mitochondrial and cell fates. In several neurological disorders, dysfunctional mitochondria show significant changes in gene and protein expression of the MQC and contribute to the pathophysiological mechanisms of cell damage. In this study, we evaluated the main gene and protein expression involved in the MQC in rats receiving traumatic brain injury (TBI) of different severities. At 6, 24, 48 and 120 hours after mild TBI (mTBI) or severe TBI (sTBI), gene and protein expressions of fusion and fission were measured in brain tissue homogenates. Compared to intact brain controls, results showed that genes and proteins inducing fusion or fission were upregulated and downregulated, respectively, in mTBI, but downregulated and upregulated, respectively, in sTBI. In particular, OPA1, regulating inner membrane dynamics, cristae remodelling, oxidative phosphorylation, was post-translationally cleaved generating differential amounts of long and short OPA1 in mTBI and sTBI. Corroborated by data referring to citrate synthase, these results confirm the transitory (mTBI) or permanent (sTBI) mitochondrial dysfunction, enhancing MQC importance to maintain cell functions and indicating in OPA1 an attractive potential therapeutic target for TBI.

Genetic Ablation of Calcium-independent Phospholipase A2γ Induces Glomerular Injury in Mice*

PubMed Central

Elimam, Hanan; Papillon, Joan; Kaufman, Daniel R.; Guillemette, Julie; Aoudjit, Lamine; Gross, Richard W.; Takano, Tomoko; Cybulsky, Andrey V.

2016-01-01

Glomerular visceral epithelial cells (podocytes) play a critical role in the maintenance of glomerular permselectivity. Podocyte injury, manifesting as proteinuria, is the cause of many glomerular diseases. We reported previously that calcium-independent phospholipase A2γ (iPLA2γ) is cytoprotective against complement-mediated glomerular epithelial cell injury. Studies in iPLA2γ KO mice have demonstrated an important role for iPLA2γ in mitochondrial lipid turnover, membrane structure, and metabolism. The aim of the present study was to employ iPLA2γ KO mice to better understand the role of iPLA2γ in normal glomerular and podocyte function as well as in glomerular injury. We show that deletion of iPLA2γ did not cause detectable albuminuria; however, it resulted in mitochondrial structural abnormalities and enhanced autophagy in podocytes as well as loss of podocytes in aging KO mice. Moreover, after induction of anti-glomerular basement membrane nephritis in young mice, iPLA2γ KO mice exhibited significantly increased levels of albuminuria, podocyte injury, and loss of podocytes compared with wild type. Thus, iPLA2γ has a protective functional role in the normal glomerulus and in glomerulonephritis. Understanding the role of iPLA2γ in glomerular pathophysiology provides opportunities for the development of novel therapeutic approaches to glomerular injury and proteinuria. PMID:27226532

Dietary and plant polyphenols exert neuroprotective effects and improve cognitive function in cerebral ischemia.

PubMed

Panickar, Kiran S; Jang, Saebyeol

2013-08-01

Cerebral ischemia is caused by an interruption of blood flow to the brain which generally leads to irreversible brain damage. Ischemic injury is associated with vascular leakage, inflammation, tissue injury, and cell death. Cellular changes associated with ischemia include impairment of metabolism, energy failure, free radical production, excitotoxicity, altered calcium homeostasis, and activation of proteases all of which affect brain functioning and also contribute to longterm disabilities including cognitive decline. Inflammation, mitochondrial dysfunction, increased oxidative/nitrosative stress, and intracellular calcium overload contribute to brain injury including cell death and brain edema. However, there is a paucity of agents that can effectively reduce cerebral damage and hence considerable attention has focused on developing newer agents with more efficacy and fewer side-effects. Polyphenols are natural compounds with variable phenolic structures and are rich in vegetables, fruits, grains, bark, roots, tea, and wine. Most polyphenols have antioxidant, anti-inflammatory, and anti-apoptotic properties and their protective effects on mitochondrial functioning, glutamate uptake, and regulating intracellular calcium levels in ischemic injury in vitro have been demonstrated. This review will assess the current status of the potential effects of polyphenols in reducing cerebral injury and improving cognitive function in ischemia in animal and human studies. In addition, the review will also examine available patents in nutrition and agriculture that relates to cerebral ischemic injury with an emphasis on plant polyphenols.

Differential effects of buffer pH on Ca2+-induced ROS emission with inhibited mitochondrial complexes I and III

PubMed Central

Lindsay, Daniel P.; Camara, Amadou K. S.; Stowe, David F.; Lubbe, Ryan; Aldakkak, Mohammed

2015-01-01

Excessive mitochondrial reactive oxygen species (ROS) emission is a critical component in the etiology of ischemic injury. Complex I and complex III of the electron transport chain are considered the primary sources of ROS emission during cardiac ischemia and reperfusion (IR) injury. Several factors modulate ischemic ROS emission, such as an increase in extra-matrix Ca2+, a decrease in extra-matrix pH, and a change in substrate utilization. Here we examined the combined effects of these factors on ROS emission from respiratory complexes I and III under conditions of simulated IR injury. Guinea pig heart mitochondria were suspended in experimental buffer at a given pH and incubated with or without CaCl2. Mitochondria were then treated with either pyruvate, a complex I substrate, followed by rotenone, a complex I inhibitor, or succinate, a complex II substrate, followed by antimycin A, a complex III inhibitor. H2O2 release rate and matrix volume were compared with and without adding CaCl2 and at pH 7.15, 6.9, or 6.5 with pyruvate + rotenone or succinate + antimycin A to simulate conditions that may occur during in vivo cardiac IR injury. We found a large increase in H2O2 release with high [CaCl2] and pyruvate + rotenone at pH 6.9, but not at pHs 7.15 or 6.5. Large increases in H2O2 release rate also occurred at each pH with high [CaCl2] and succinate + antimycin A, with the highest levels observed at pH 7.15. The increases in H2O2 release were associated with significant mitochondrial swelling, and both H2O2 release and swelling were abolished by cyclosporine A, a desensitizer of the mitochondrial permeability transition pore (mPTP). These results indicate that ROS production by complex I and by complex III is differently affected by buffer pH and Ca2+ loading with mPTP opening. The study suggests that changes in the levels of cytosolic Ca2+ and pH during IR alter the relative amounts of ROS produced at mitochondrial respiratory complex I and complex III. PMID:25805998

Emerging Mitochondrial Therapeutic Targets in Optic Neuropathies.

PubMed

Lopez Sanchez, M I G; Crowston, J G; Mackey, D A; Trounce, I A

2016-09-01

Optic neuropathies are an important cause of blindness worldwide. The study of the most common inherited mitochondrial optic neuropathies, Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (ADOA) has highlighted a fundamental role for mitochondrial function in the survival of the affected neuron-the retinal ganglion cell. A picture is now emerging that links mitochondrial dysfunction to optic nerve disease and other neurodegenerative processes. Insights gained from the peculiar susceptibility of retinal ganglion cells to mitochondrial dysfunction are likely to inform therapeutic development for glaucoma and other common neurodegenerative diseases of aging. Despite it being a fast-evolving field of research, a lack of access to human ocular tissues and limited animal models of mitochondrial disease have prevented direct retinal ganglion cell experimentation and delayed the development of efficient therapeutic strategies to prevent vision loss. Currently, there are no approved treatments for mitochondrial disease, including optic neuropathies caused by primary or secondary mitochondrial dysfunction. Recent advances in eye research have provided important insights into the molecular mechanisms that mediate pathogenesis, and new therapeutic strategies including gene correction approaches are currently being investigated. Here, we review the general principles of mitochondrial biology relevant to retinal ganglion cell function and provide an overview of the major optic neuropathies with mitochondrial involvement, LHON and ADOA, whilst highlighting the emerging link between mitochondrial dysfunction and glaucoma. The pharmacological strategies currently being trialed to improve mitochondrial dysfunction in these optic neuropathies are discussed in addition to emerging therapeutic approaches to preserve retinal ganglion cell function. Copyright © 2016 Elsevier Inc. All rights reserved.

Regulator of G Protein Signaling 6 Protects the Heart from Ischemic Injury

PubMed Central

Chakravarti, Bandana; Mabe, Nathaniel W.; Seeley, Sarah L.; Bui, Albert D.; Yang, Jianqi; Watts, Stephanie W.; Neubig, Richard R.; Fisher, Rory A.

2017-01-01

Gαi-coupled receptors play important roles in protecting the heart from ischemic injury. Regulator of G protein signaling (RGS) proteins suppress Gαi signaling by accelerating the GTPase activity of Gαi subunits. However, the roles of individual RGS proteins in modulating ischemic injury are unknown. In this study, we investigated the effect of RGS6 deletion on myocardial sensitivity to ischemic injury. Hearts from RGS6 knockout (RGS6−/−) and RGS6 wild-type (RGS6+/+) mice were subjected to 30 minutes of ischemia and 2 hours of reperfusion on a Langendorff heart apparatus. Infarcts in RGS6−/− hearts were significantly larger than infarcts in RGS6+/+ hearts. RGS6−/− hearts also exhibited increased phosphorylation of β2-adrenergic receptors and G protein–coupled receptor kinase 2 (GRK2). Mitochondrial GRK2 as well as caspase-3 cleavage were increased significantly in RGS6−/− hearts compared with RGS6+/+ hearts after ischemia. Chronic propranolol treatment of mice prevented the observed increases in ischemic injury and the GRK2 phosphorylation observed in RGS6−/− hearts. Our findings suggest that loss of RGS6 predisposes the ventricle to prodeath signaling through a β2AR-GRK2–dependent signaling mechanism, and they provide evidence for a protective role of RGS6 in the ischemic heart. Individuals expressing genetic polymorphisms that suppress the activity of RGS6 may be at increased risk of cardiac ischemic injury. Furthermore, the development of agents that increase RGS6 expression or activity might provide a novel strategy for the treatment of ischemic heart disease. PMID:28035008

Rapamycin Protects against Myocardial Ischemia-Reperfusion Injury through JAK2-STAT3 Signaling Pathway

PubMed Central

Das, Anindita; Salloum, Fadi N.; Durrant, David; Ockaili, Ramzi; Kukreja, Rakesh C

2012-01-01

Rapamycin (Sirolimus®) is used to prevent rejection of transplanted organs and coronary restenosis. We reported that rapamycin induced cardioprotection against ischemia-reperfusion (I/R) injury through opening of mitochondrial KATP channels. However, signaling mechanisms in rapamycin-induced cardioprotection are currently unknown. Considering that STAT3 is protective in the heart, we investigated the potential role of this transcription factor in rapamycin-induced protection against (I/R) injury. Adult male ICR mice were treated with rapamycin (0.25 mg/kg, i.p.) or vehicle (DMSO) with/without inhibitor of JAK2 (AG-490) or STAT3 (stattic). One hour later, the hearts were subjected to I/R either in Langendorf mode or in situ ligation of left coronary artery. Additionally, primary murine cardiomyocytes were subjected to simulated ischemia/reoxygenation (SI-RO) injury in vitro. For in situ targeted knockdown of STAT3, lentiviral vector containing short hairpin RNA was injected into left ventricle 3 weeks prior to initiating I/R injury. Infarct size, cardiac function, cardiomyocyte necrosis and apoptosis were assessed. Rapamycin reduced infarct size, improved cardiac function following I/R, limited cardiomyocytes necrosis as well as apoptosis following SI-RO which were blocked by AG-490 and stattic. In situ knock-down of STAT3 attenuated rapamycin-induced protection against I/R injury. Rapamycin triggered unique cardioprotecive signaling including phosphorylation of ERK, STAT3, eNOS and glycogen synthase kinase-3β in concert with increased prosurvival Bcl-2 to Bax ratio. Our data suggest that JAK2-STAT3 signaling plays an essential role in rapamycin-induced cardioprotection. We propose that rapamycin is a novel and clinically relevant pharmacological strategy to target STAT3 activation for treatment of myocardial infarction. PMID:22999860

Mitochondrial Disease: Clinical Aspects, Molecular Mechanisms, Translational Science, and Clinical Frontiers

PubMed Central

Thornton, Ben; Cohen, Bruce; Copeland, William; Maria, Bernard L.

2015-01-01

Mitochondrial medicine provides a metabolic perspective on the pathology of conditions linked with inadequate oxidative phosphorylation. Dysfunction in the mitochondrial machinery can result in improper energy production, leading to cellular injury or even apoptosis. Clinical presentations are often subtle, so clinicians must have a high index of suspicion to make early diagnoses. Symptoms could include muscle weakness and pain, seizures, loss of motor control, decreased visual and auditory functions, metabolic acidosis, acute developmental regression, and immune system dysfunction. The 2013 Neurobiology of Disease in Children Symposium, held in conjunction with the 42nd Annual Meeting of the Child Neurology Society, aimed to (1) describe accepted clinical phenotypes of mitochondrial disease produced from various mitochondrial mutations, (2) discuss contemporary understanding of molecular mechanisms that contribute to disease pathology, (3) highlight the systemic effects produced by dysfunction within the mitochondrial machinery, and (4) introduce current strategies that are being translated from bench to bedside as potential therapeutics. PMID:24916430

Mitochondria in the nervous system: From health to disease, Part I.

PubMed

Polster, Brian M; Carrì, Maria Teresa; Beart, Philip M

2017-10-01

In Part I of this Special Issue on "Mitochondria in the Nervous System: From Health to Disease", the editors bring together contributions from experts in brain mitochondrial research to provide an up-to-date overview of mitochondrial functioning in physiology and pathology. The issue provides cutting edge reviews on classical areas of mitochondrial biology that include energy substrate utilization, calcium handling, mitochondria-endoplasmic reticulum communication, and cell death regulation. Additional reviews and original research articles touch upon key mitochondrial defects seen across multiple neurodegenerative conditions, including fragmentation, loss of respiratory capacity, calcium overload, elevated reactive oxygen species generation, perturbed NAD + metabolism, altered protein acetylation, and compromised mitophagy. Emerging links between the genetics of neurodegenerative disorders and disruption in mitochondrial function are discussed, and a new mouse model of Complex I deficiency is described. Finally, novel ways to rescue mitochondrial structure and function in acute and chronic brain injury are explored. Copyright © 2017. Published by Elsevier Ltd.

Excessive Hepatic Mitochondrial TCA Cycle and Gluconeogenesis in Humans with Nonalcoholic Fatty Liver Disease

PubMed Central

Sunny, Nishanth E.; Parks, Elizabeth J.; Browning, Jeffrey D.; Burgess, Shawn C.

2013-01-01

Summary Approximately one-third of the U.S. population has nonalcoholic fatty liver disease (NAFLD), a condition closely associated with insulin resistance and increased risk of liver injury. Dysregulated mitochondrial metabolism is central in these disorders, but the manner and degree of dysregulation are disputed. This study tested whether humans with NAFLD have abnormal in vivo hepatic mitochondrial metabolism. Subjects with low (3.0%) and high (17%) intrahepatic triglyceride (IHTG) were studied using 2H and 13C tracers to evaluate systemic lipolysis, hepatic glucose production, and mitochondrial pathways (TCA cycle, anaplerosis, and ketogenesis). Individuals with NAFLD had 50% higher rates of lipolysis and 30% higher rates of gluconeogenesis. There was a positive correlation between IHTG content and both mitochondrial oxidative and anaplerotic fluxes. These data indicate that mitochondrial oxidative metabolism is ∼2-fold greater in those with NAFLD, providing a potential link between IHTG content, oxidative stress, and liver damage. PMID:22152305

Arsenic induces apoptosis in mouse liver is mitochondria dependent and is abrogated by N-acetylcysteine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santra, Amal; Chowdhury, Abhijit; Ghatak, Subhadip

2007-04-15

Arsenicosis, caused by arsenic contamination of drinking water supplies, is a major public health problem in India and Bangladesh. Chronic liver disease, often with portal hypertension occurs in chronic arsenicosis, contributes to the morbidity and mortality. The early cellular events that initiate liver cell injury due to arsenicosis have not been studied. Our aim was to identify the possible mechanisms related to arsenic-induced liver injury in mice. Liver injury was induced in mice by arsenic treatment. The liver was used for mitochondrial oxidative stress, mitochondrial permeability transition (MPT). Evidence of apoptosis was sought by TUNEL test, caspase assay and histology.more » Pretreatment with N-acetyl-L-cysteine (NAC) was done to modulate hepatic GSH level. Arsenic treatment in mice caused liver injury associated with increased oxidative stress in liver mitochondria and alteration of MPT. Altered MPT facilitated cytochrome c release in the cytosol, activation of caspase 9 and caspase 3 activities and apoptotic cell death. Pretreatment of NAC to arsenic-treated mice abrogated all these alteration suggesting a glutathione (GSH)-dependent mechanism. Oxidative stress in mitochondria and inappropriate MPT are important in the pathogenesis of arsenic induced apoptotic liver cell injury. The phenomenon is GSH dependent and supplementation of NAC might have beneficial effects.« less

Limonene protects osteoblasts against methylglyoxal-derived adduct formation by regulating glyoxalase, oxidative stress, and mitochondrial function.

PubMed

Suh, Kwang Sik; Chon, Suk; Choi, Eun Mi

2017-12-25

Methylglyoxal (MG) is a potent protein glycating agent and an important precursor of advanced glycation end products, which are involved in the pathogenesis of diabetic osteopathy. In this study, we investigated the effects of limonene on MG-induced damage in osteoblastic MC3T3-E1 cells. Pretreating cells with limonene prevented MG-induced protein adduct formation, tumor necrosis factor alpha and interleukin-6 release, mitochondrial superoxide production, and cardiolipin peroxidation. In addition, limonene increased glyoxalase I activity, and glutathione and heme oxygenase-1 levels in the presence of MG. Pretreatment with limonene prior to MG exposure reduced MG-induced mitochondrial dysfunction by preventing mitochondrial membrane potential dissipation and adenosine triphosphate loss, and reduced the levels of adenosine monophosphate-activated protein kinase, peroxisome proliferator activated receptor γ coactivator 1α, and nitric oxide. These results demonstrate that limonene may prevent the development of diabetic osteopathy. Copyright © 2017 Elsevier B.V. All rights reserved.

Activating Nrf-2 Signaling Depresses Unilateral Ureteral Obstruction-Evoked Mitochondrial Stress-Related Autophagy, Apoptosis and Pyroptosis in Kidney

PubMed Central

Chung, Shue Dong; Lai, Ting Yu; Chien, Chiang Ting; Yu, Hong Jen

2012-01-01

Exacerbated oxidative stress and inflammation may induce three types of programmed cell death, autophagy, apoptosis and pyroptosis in unilateral ureteral obstruction (UUO) kidney. Sulforaphane activating NF-E2-related nuclear factor erythroid-2 (Nrf-2) signaling may ameliorate UUO-induced renal damage. UUO was induced in the left kidney of female Wistar rats. The level of renal blood flow, cortical and medullary oxygen tension and reactive oxygen species (ROS) was evaluated. Fibrosis, ED-1 (macrophage/monocyte) infiltration, oxidative stress, autophagy, apoptosis and pyroptosis were evaluated by immunohistochemistry and Western blot in UUO kidneys. Effects of sulforaphane, an Nrf-2 activator, on Nrf-2- and mitochondrial stress-related proteins and renal injury were examined. UUO decreased renal blood flow and oxygen tension and increased renal ROS, 3-nitrotyrosine stain, ED-1 infiltration and fibrosis. Enhanced renal tubular Beclin-1 expression started at 4 h UUO and further enhanced at 3d UUO, whereas increased Atg-5-Atg12 and LC3-II expression were found at 3d UUO. Increased renal Bax/Bcl-2 ratio, caspase 3 and PARP fragments, apoptosis formation associated with increased caspase 1 and IL-1β expression for pyroptosis formation were started from 3d UUO. UUO reduced nuclear Nrf-2 translocation, increased cytosolic and inhibitory Nrf-2 expression, increased cytosolic Bax translocation to mitochondrial and enhanced mitochondrial Cytochrome c release into cytosol of the UUO kidneys. Sulforaphane significantly increased nuclear Nrf-2 translocation and decreased mitochondrial Bax translocation and Cytochrome c release into cytosol resulting in decreased renal injury. In conclusion, sulforaphane via activating Nrf-2 signaling preserved mitochondrial function and suppressed UUO-induced renal oxidative stress, inflammation, fibrosis, autophagy, apoptosis and pyroptosis. PMID:23071780

Sevoflurane postconditioning protects the myocardium against ischemia/reperfusion injury via activation of the JAK2–STAT3 pathway

PubMed Central

Wu, Jianjiang; Yu, Jin; Xie, Peng; Maimaitili, Yiliyaer; Wang, Jiang; Yang, Long; Ma, Haiping; Zhang, Xing; Yang, Yining

2017-01-01

Background Sevoflurane postconditioning (S-post) has similar cardioprotective effects as ischemic preconditioning. However, the underlying mechanism of S-post has not been fully elucidated. Janus kinase signaling transduction/transcription activator (JAK2–STAT3) plays an important role in cardioprotection. The purpose of this study was to determine whether the cardioprotective effects of S-post are associated with activation of the JAK2–STAT3 signal pathway. Methods An adult male Sprague–Dawley (SD) rat model of myocardial ischemia/reperfusion (I/R) injury was established using the Langendorff isolated heart perfusion apparatus. At the beginning of reperfusion, 2.4% sevoflurane alone or in combination with AG490 (a JAK2 selective inhibitor) was used as a postconditioning treatment. The cardiac function indicators, myocardial infarct size, lactic dehydrogenase (LDH) release, mitochondrial ultrastructure, mitochondrial reactive oxygen species (ROS) generation rates, ATP content, protein expression of p-JAK, p-STAT3, Bcl-2 and Bax were measured. Results Compared with the I/R group, S-post significantly increased the expression of p-JAK, p-STAT3 and Bcl-2 and reduced the protein expression of Bax, which markedly decreased the myocardial infarction areas, improved the cardiac function indicators and the mitochondrial ultrastructure, decreased the mitochondrial ROS and increased the ATP content. However, the cardioprotective effects of S-post were abolished by treatment with a JAK2 selective inhibitor (p < 0.05). Conclusion This study demonstrates that the cardioprotective effects of S-post are associated with the activation of JAK2–STAT3. The mechanism may be related to an increased expression of p-JAK2 and p-STAT3 after S-post, which reduced mitochondrial ROS generation and increased mitochondrial ATP content, thereby reducing apoptosis and myocardial infarct size. PMID:28392989

Dual role of mitochondria in producing melatonin and driving GPCR signaling to block cytochrome c release.

PubMed

Suofu, Yalikun; Li, Wei; Jean-Alphonse, Frédéric G; Jia, Jiaoying; Khattar, Nicolas K; Li, Jiatong; Baranov, Sergei V; Leronni, Daniela; Mihalik, Amanda C; He, Yanqing; Cecon, Erika; Wehbi, Vanessa L; Kim, JinHo; Heath, Brianna E; Baranova, Oxana V; Wang, Xiaomin; Gable, Matthew J; Kretz, Eric S; Di Benedetto, Giulietta; Lezon, Timothy R; Ferrando, Lisa M; Larkin, Timothy M; Sullivan, Mara; Yablonska, Svitlana; Wang, Jingjing; Minnigh, M Beth; Guillaumet, Gérald; Suzenet, Franck; Richardson, R Mark; Poloyac, Samuel M; Stolz, Donna B; Jockers, Ralf; Witt-Enderby, Paula A; Carlisle, Diane L; Vilardaga, Jean-Pierre; Friedlander, Robert M

2017-09-19

G protein-coupled receptors (GPCRs) are classically characterized as cell-surface receptors transmitting extracellular signals into cells. Here we show that central components of a GPCR signaling system comprised of the melatonin type 1 receptor (MT 1 ), its associated G protein, and β-arrestins are on and within neuronal mitochondria. We discovered that the ligand melatonin is exclusively synthesized in the mitochondrial matrix and released by the organelle activating the mitochondrial MT 1 signal-transduction pathway inhibiting stress-mediated cytochrome c release and caspase activation. These findings coupled with our observation that mitochondrial MT 1 overexpression reduces ischemic brain injury in mice delineate a mitochondrial GPCR mechanism contributing to the neuroprotective action of melatonin. We propose a new term, "automitocrine," analogous to "autocrine" when a similar phenomenon occurs at the cellular level, to describe this unexpected intracellular organelle ligand-receptor pathway that opens a new research avenue investigating mitochondrial GPCR biology.

Estrogen-related receptor-α (ERRα) deficiency in skeletal muscle impairs regeneration in response to injury

PubMed Central

LaBarge, Samuel; McDonald, Marisa; Smith-Powell, Leslie; Auwerx, Johan; Huss, Janice M.

2014-01-01

The estrogen-related receptor-α (ERRα) regulates mitochondrial biogenesis and glucose and fatty acid oxidation during differentiation in skeletal myocytes. However, whether ERRα controls metabolic remodeling during skeletal muscle regeneration in vivo is unknown. We characterized the time course of skeletal muscle regeneration in wild-type (M-ERRαWT) and muscle-specific ERRα−/− (M-ERRα−/−) mice after injury by intramuscular cardiotoxin injection. M-ERRα−/− mice exhibited impaired regeneration characterized by smaller myofibers with increased centrally localized nuclei and reduced mitochondrial density and cytochrome oxidase and citrate synthase activities relative to M-ERRαWT. Transcript levels of mitochondrial transcription factor A, nuclear respiratory factor-2a, and peroxisome proliferator-activated receptor (PPAR)-γ coactivator (PGC)-1β, were downregulated in the M-ERRα−/− muscles at the onset of myogenesis. Furthermore, coincident with delayed myofiber recovery, we observed reduced muscle ATP content (−45% vs. M-ERRαWT) and enhanced AMP-activated protein kinase (AMPK) activation in M-ERRα−/− muscle. We subsequently demonstrated that pharmacologic postinjury AMPK activation was sufficient to delay muscle regeneration in WT mice. AMPK activation induced ERRα transcript expression in M-ERRαWT muscle and in C2C12 myotubes through induction of the Esrra promoter, indicating that ERRα may control gene regulation downstream of the AMPK pathway. Collectively, these results suggest that ERRα deficiency during muscle regeneration impairs recovery of mitochondrial energetic capacity and perturbs AMPK activity, resulting in delayed myofiber repair.—LaBarge, S., McDonald, M., Smith-Powell, L., Auwerx, J., Huss, J. M. Estrogen-related receptor-α (ERRα) deficiency in skeletal muscle impairs regeneration in response to injury. PMID:24277576

Novel interactions of mitochondria and reactive oxygen/nitrogen species in alcohol mediated liver disease

PubMed Central

Mantena, Sudheer K; King, Adrienne L; Andringa, Kelly K; Landar, Aimee; Darley-Usmar, Victor; Bailey, Shannon M

2007-01-01

Mitochondrial dysfunction is known to be a contributing factor to a number of diseases including chronic alcohol induced liver injury. While there is a detailed understanding of the metabolic pathways and proteins of the liver mitochondrion, little is known regarding how changes in the mitochondrial proteome may contribute to the development of hepatic pathologies. Emerging evidence indicates that reactive oxygen and nitrogen species disrupt mitochondrial function through post-translational modifications to the mitochondrial proteome. Indeed, various new affinity labeling reagents are available to test the hypothesis that post-translational modification of proteins by reactive species contributes to mitochondrial dysfunction and alcoholic fatty liver disease. Specialized proteomic techniques are also now available, which allow for identification of defects in the assembly of multi-protein complexes in mitochondria and the resolution of the highly hydrophobic proteins of the inner membrane. In this review knowledge gained from the study of changes to the mitochondrial proteome in alcoholic hepatotoxicity will be described and placed into a mechanistic framework to increase understanding of the role of mitochondrial dysfunction in liver disease. PMID:17854139

Mitochondrial Metabolism in Aging Heart

PubMed Central

Lesnefsky, Edward J.; Chen, Qun; Hoppel, Charles L.

2016-01-01

Altered mitochondrial metabolism is the underlying basis for the increased sensitivity in the aged heart to stress. The aged heart exhibits impaired metabolic flexibility, with a decreased capacity to oxidize fatty acids and enhanced dependence on glucose metabolism. Aging impairs mitochondrial oxidative phosphorylation, with a greater role played by the mitochondria located between the myofibrils, the interfibrillar mitochondria. With aging, there is a decrease in activity of complexes III and IV, which account for the decrease in respiration. Furthermore, aging decreases mitochondrial content among the myofibrils. The end result is that in the interfibrillar area there is an approximate 50% decrease in mitochondrial function, affecting all substrates. The defective mitochondria persist in the aged heart, leading to enhanced oxidant production and oxidative injury and the activation of oxidant signaling for cell death. Aging defects in mitochondria represent new therapeutic targets, whether by manipulation of the mitochondrial proteome, modulation of electron transport, activation of biogenesis or mitophagy, or the regulation of mitochondrial fission and fusion. These mechanisms provide new ways to attenuate cardiac disease in elders by preemptive treatment of age-related defects, in contrast to the treatment of disease-induced dysfunction. PMID:27174952

Melatonin prevents abnormal mitochondrial dynamics resulting from the neurotoxicity of cadmium by blocking calcium-dependent translocation of Drp1 to the mitochondria.

PubMed

Xu, Shangcheng; Pi, Huifeng; Zhang, Lei; Zhang, Nixian; Li, YuMing; Zhang, Huiliang; Tang, Ju; Li, Huijuan; Feng, Min; Deng, Ping; Guo, Pan; Tian, Li; Xie, Jia; He, Mindi; Lu, Yonghui; Zhong, Min; Zhang, Yanwen; Wang, Wang; Reiter, Russel J; Yu, Zhengping; Zhou, Zhou

2016-04-01

Cadmium (Cd) is a persistent environmental toxin and occupational pollutant that is considered to be a potential risk factor in the development of neurodegenerative diseases. Abnormal mitochondrial dynamics are increasingly implicated in mitochondrial damage in various neurological pathologies. The aim of this study was to investigate whether the disturbance of mitochondrial dynamics contributed to Cd-induced neurotoxicity and whether melatonin has any neuroprotective properties. After cortical neurons were exposed to 10 μM cadmium chloride (CdCl2 ) for various periods (0, 3, 6, 12, and 24 hr), the morphology of their mitochondria significantly changed from the normal tubular networks into punctuated structures within 3 hr. Following this pronounced mitochondrial fragmentation, Cd treatment led to signs of mitochondrial dysfunction, including excess reactive oxygen species (ROS) production, decreased ATP content, and mitochondrial membrane potential (▵Ψm) loss. However, 1 mM melatonin pretreatment efficiently attenuated the Cd-induced mitochondrial fragmentation, which improved the turnover of mitochondrial function. In the brain tissues of rats that were intraperitoneally given 1 mg/kg CdCl2 for 7 days, melatonin also ameliorated excessive mitochondrial fragmentation and mitochondrial damage in vivo. Melatonin's protective effects were attributed to its roles in preventing cytosolic calcium ([Ca(2+) ]i ) overload, which blocked the recruitment of Drp1 from the cytoplasm to the mitochondria. Taken together, our results are the first to demonstrate that abnormal mitochondrial dynamics is involved in cadmium-induced neurotoxicity. Melatonin has significant pharmacological potential in protecting against the neurotoxicity of Cd by blocking the disbalance of mitochondrial fusion and fission. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Analysis on violence injury incidence and prevention in China].

PubMed

Er, Yuliang; Gao, Xin; Duan, Leilei; Wang, Yuan; Deng, Xiao; Ji, Cuirong; Ye, Pengpeng; Jin, Ye; Wang, Linhong

2016-01-01

To understand the incidence of violence injury and its prevention in China, and provide reference for the prevention and control of violence injury. The violence injury data in China were collected from national death surveillance data set (2006-2013) and national injury surveillance system (2013) for the descriptive epidemiological analysis on the incidence of violence injury and related death. The laws and policies about violence injury prevention, related data collection capacity and violence injury prevention programs in China were described. The violence injury mortality declined by 46.3% during 2006-2013 from 1.21/100000 to 0.65/100000. The incidence of violence injury death in males peaked in age group 30-34 years (1.42/100000), and it was low in age group<15 years. Three peaks of violence injury death were found in females, i.e. 0.84/100000 in infants, 0.72/100000 in age group 30-34 years and 1.18/100000 in age group≥85 years. The laws and policies about violence injury prevention were imperfect, and the data about violence injury were limited. Most prevention programs were limited in scale and duration. The crude and standardized violence injury mortality declined in China during 2006-2013. It is necessary to conduct gender specific prevention strategies and improve the related law and policy development, data collection and prevention service.

Mitochondrial Cyclophilin D in Vascular Oxidative Stress and Hypertension.

PubMed

Itani, Hana A; Dikalova, Anna E; McMaster, William G; Nazarewicz, Rafal R; Bikineyeva, Alfiya T; Harrison, David G; Dikalov, Sergey I

2016-06-01

Vascular superoxide (O˙2 (-)) and inflammation contribute to hypertension. The mitochondria are an important source of O˙2 (-); however, the regulation of mitochondrial O˙2 (-) and the antihypertensive potential of targeting the mitochondria remain poorly defined. Angiotensin II and inflammatory cytokines, such as interleukin 17A and tumor necrosis factor-α (TNFα) significantly contribute to hypertension. We hypothesized that angiotensin II and cytokines co-operatively induce cyclophilin D (CypD)-dependent mitochondrial O˙2 (-) production in hypertension. We tested whether CypD inhibition attenuates endothelial oxidative stress and reduces hypertension. CypD depletion in CypD(-/-) mice prevents overproduction of mitochondrial O˙2 (-) in angiotensin II-infused mice, attenuates hypertension by 20 mm Hg, and improves vascular relaxation compared with wild-type C57Bl/6J mice. Treatment of hypertensive mice with the specific CypD inhibitor Sanglifehrin A reduces blood pressure by 28 mm Hg, inhibits production of mitochondrial O˙2 (-) by 40%, and improves vascular relaxation. Angiotensin II-induced hypertension was associated with CypD redox activation by S-glutathionylation, and expression of the mitochondria-targeted H2O2 scavenger, catalase, abolished CypD S-glutathionylation, prevented stimulation mitochondrial O˙2 (-), and attenuated hypertension. The functional role of cytokine-angiotensin II interplay was confirmed by co-operative stimulation of mitochondrial O˙2 (-) by 3-fold in cultured endothelial cells and impairment of aortic relaxation incubated with combination of angiotensin II, interleukin 17A, and tumor necrosis factor-α which was prevented by CypD depletion or expression of mitochondria-targeted SOD2 and catalase. These data support a novel role of CypD in hypertension and demonstrate that targeting CypD decreases mitochondrial O˙2 (-), improves vascular relaxation, and reduces hypertension. © 2016 American Heart Association, Inc.

Epoxyeicosatrienoic acids pretreatment improves amyloid β-induced mitochondrial dysfunction in cultured rat hippocampal astrocytes.

PubMed

Sarkar, Pallabi; Zaja, Ivan; Bienengraeber, Martin; Rarick, Kevin R; Terashvili, Maia; Canfield, Scott; Falck, John R; Harder, David R

2014-02-15

Amyloid-β (Aβ) has long been implicated as a causative protein in Alzheimer's disease. Cellular Aβ accumulation is toxic and causes mitochondrial dysfunction, which precedes clinical symptoms of Alzheimer's disease pathology. In the present study, we explored the possible use of epoxyeicosatrienoic acids (EETs), epoxide metabolites of arachidonic acid, as therapeutic target against Aβ-induced mitochondrial impairment using cultured neonatal hippocampal astrocytes. Inhibition of endogenous EET production by a selective epoxygenase inhibitor, MS-PPOH, caused a greater reduction in mitochondrial membrane potential in the presence of Aβ (1, 10 μM) exposure versus absence of Aβ. MS-PPOH preincubation also aggravated Aβ-induced mitochondrial fragmentation. Preincubation of the cells with either 14,15- or 11,12-EET prevented this mitochondrial depolarization and fragmentation. EET pretreatment also further improved the reduction observed in mitochondrial oxygen consumption in the presence of Aβ. Preincubation of the cells with EETs significantly improved cellular respiration under basal condition and in the presence of the protonophore, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP). The uncoupling of ATP synthase from the electron transfer chain that occurred in Aβ-treated cells was also prevented by preincubation with EETs. Lastly, cellular reactive oxygen species production, a hallmark of Aβ toxicity, also showed significant reduction in the presence of EETs. We have previously shown that Aβ reduces EET synthesis in rat brain homogenates and cultured hippocampal astrocytes and neurons (Sarkar P, Narayanan J, Harder DR. Differential effect of amyloid beta on the cytochrome P450 epoxygenase activity in rat brain. Neuroscience 194: 241-249, 2011). We conclude that reduction of endogenous EETs may be one of the mechanisms through which Aβ inflicts toxicity and thus supplementing the cells with exogenous EETs improves mitochondrial dynamics and prevents metabolic impairment.

Mechanisms, Prediction, and Prevention of ACL Injuries: Cut Risk With Three Sharpened and Validated Tools

PubMed Central

Hewett, Timothy E.; Myer, Gregory D.; Ford, Kevin R.; Paterno, Mark V.; Quatman, Carmen E.

2017-01-01

Economic and societal pressures influence modern medical practice to develop and implement prevention strategies. Anterior cruciate ligament (ACL) injury devastates the knee joint leading to short term disability and long term sequelae. Due to the high risk of long term osteoarthritis in all treatment populations following ACL injury, prevention is the only effective intervention for this life-altering disruption in knee health. The “Sequence of Prevention” Model provides a framework to monitor progress towards the ultimate goal of preventing ACL injuries. Utilizing this model, our multidisciplinary collaborative research team has spent the last decade working to delineate injury mechanisms, identify injury risk factors, predict which athletes are at-risk for injury, and develop ACL injury prevention programs. Within this model of injury prevention, modifiable factors (biomechanical and neuromuscular) related to injury mechanisms likely provide the best opportunity for intervention strategies aimed to decrease the risk of ACL injury, particularly in female athletes. Knowledge advancements have led to the development of potential solutions that allow athletes to compete with lowered risk of ACL injury. Design and integration of personalized clinical assessment tools and targeted prevention strategies for athletes at high risk for ACL injury may transform current prevention practices and ultimately significantly reduce ACL injury incidence. This 2016 OREF Clinical Research Award focuses on the authors' work and contributions to the field. The author's acknowledge the many research groups who have contributed to the current state of knowledge in the fields of ACL injury mechanisms, injury risk screening and injury prevention strategies. PMID:27612195

Mitochondrial impairment contributes to cocaine-induced cardiac dysfunction: Prevention by the targeted antioxidant MitoQ.

PubMed

Vergeade, Aurélia; Mulder, Paul; Vendeville-Dehaudt, Cathy; Estour, François; Fortin, Dominique; Ventura-Clapier, Renée; Thuillez, Christian; Monteil, Christelle

2010-09-01

The goal of this study was to assess mitochondrial function and ROS production in an experimental model of cocaine-induced cardiac dysfunction. We hypothesized that cocaine abuse may lead to altered mitochondrial function that in turn may cause left ventricular dysfunction. Seven days of cocaine administration to rats led to an increased oxygen consumption detected in cardiac fibers, specifically through complex I and complex III. ROS levels were increased, specifically in interfibrillar mitochondria. In parallel there was a decrease in ATP synthesis, whereas no difference was observed in subsarcolemmal mitochondria. This uncoupling effect on oxidative phosphorylation was not detectable after short-term exposure to cocaine, suggesting that these mitochondrial abnormalities were a late rather than a primary event in the pathological response to cocaine. MitoQ, a mitochondrial-targeted antioxidant, was shown to completely prevent these mitochondrial abnormalities as well as cardiac dysfunction characterized here by a diastolic dysfunction studied with a conductance catheter to obtain pressure-volume data. Taken together, these results extend previous studies and demonstrate that cocaine-induced cardiac dysfunction may be due to a mitochondrial defect. Copyright 2010 Elsevier Inc. All rights reserved.

Are we having fun yet? Fostering adherence to injury preventive exercise recommendations in young athletes.

PubMed

Keats, Melanie R; Emery, Carolyn A; Finch, Caroline F

2012-03-01

Sport and recreational activities are the leading cause of injury in youth, yet there is increasing evidence that many sport-related injuries are preventable. For injury prevention strategies to be effective, individuals must understand, adopt and adhere to the recommended prevention strategy or programme. Despite the recognized importance of a behavioural approach, the inclusion of behavioural change strategies in sport injury prevention has been historically neglected. The purpose of this commentary is to outline the rationale for the inclusion and application of behavioural science in reducing the burden of injury by increasing adherence to proven prevention strategies. In an effort to provide an illustrative example of a behavioural change approach, the authors suggest a specific plan for the implementation of a neuromuscular training strategy to reduce the risk of lower limb injury in youth sport. Given the paucity of evidence in the sport injury prevention setting, and the lack of application of theoretical frameworks to predicting adoption and adherence to injury preventive exercise recommendations in youth sport, data from the related physical activity promotion domain is utilized to describe how sound, theory-based injury prevention exercise interventions in youth may be developed. While the question of how to facilitate behavioural change and optimize adherence to preventive exercise recommendations remains an ongoing challenge, the authors detail several strategies based on two prominent behavioural theories to aid the reader in conceptualizing, designing and implementing effective interventions. Despite the minimal application of behavioural theory within the field of sport injury prevention in youth, behavioural science has the potential to make a significant impact on the understanding and prevention of youth sport injury. Appropriate evaluation of adherence and maintenance components based on models of behavioural change should be a critical component of future injury prevention research and practice.

Cytoprotective Mechanisms in Fatty Liver Preservation against Cold Ischemia Injury: A Comparison between IGL-1 and HTK

PubMed Central

Panisello-Roselló, Arnau; Verde, Eva; Flores, Marta; Folch-Puy, Emma; Rolo, Anabela; Palmeira, Carlos; Hotter, Georgina; Adam, René; Roselló-Catafau, Joan

2018-01-01

Institute Goeorges Lopez 1 (IGL-1) and Histidine-Tryptophan-Ketoglutarate (HTK) preservation solutions are regularly used in clinical for liver transplantation besides University of Wisconsin (UW) solution and Celsior. Several clinical trials and experimental works have been carried out comparing all the solutions, however the comparative IGL-1 and HTK appraisals are poor; especially when they deal with the underlying protection mechanisms of the fatty liver graft during cold storage. Fatty livers from male obese Zücker rats were conserved for 24 h at 4 °C in IGL-1 or HTK preservation solutions. After organ recovery and rinsing of fatty liver grafts with Ringer Lactate solution, we measured the changes in mechanistic target of rapamycin (mTOR) signaling activation, liver autophagy markers (Beclin-1, Beclin-2, LC3B and ATG7) and apoptotic markers (caspase 3, caspase 9 and TUNEL). These determinations were correlated with the prevention of liver injury (aspartate and alanine aminostransferase (AST/ALT), histology) and mitochondrial damage (glutamate dehydrogenase (GLDH) and confocal microscopy findings). Liver grafts preserved in IGL-1 solution showed a marked reduction on p-TOR/mTOR ratio when compared to HTK. This was concomitant with significant increased cyto-protective autophagy and prevention of liver apoptosis, including inflammatory cytokines such as HMGB1. Together, our results revealed that IGL-1 preservation solution better protected fatty liver grafts against cold ischemia damage than HTK solution. IGL-1 protection was associated with a reduced liver damage, higher induced autophagy and decreased apoptosis. All these effects would contribute to limit the subsequent extension of reperfusion injury after graft revascularization in liver transplantation procedures. PMID:29364854

Calcium, mitochondria and oxidative stress in neuronal pathology. Novel aspects of an enduring theme.

PubMed

Chinopoulos, Christos; Adam-Vizi, Vera

2006-02-01

The interplay among reactive oxygen species (ROS) formation, elevated intracellular calcium concentration and mitochondrial demise is a recurring theme in research focusing on brain pathology, both for acute and chronic neurodegenerative states. However, causality, extent of contribution or the sequence of these events prior to cell death is not yet firmly established. Here we review the role of the alpha-ketoglutarate dehydrogenase complex as a newly identified source of mitochondrial ROS production. Furthermore, based on contemporary reports we examine novel concepts as potential mediators of neuronal injury connecting mitochondria, increased [Ca2+]c and ROS/reactive nitrogen species (RNS) formation; specifically: (a) the possibility that plasmalemmal nonselective cationic channels contribute to the latent [Ca2+]c rise in the context of glutamate-induced delayed calcium deregulation; (b) the likelihood of the involvement of the channels in the phenomenon of 'Ca2+ paradox' that might be implicated in ischemia/reperfusion injury; and (c) how ROS/RNS and mitochondrial status could influence the activity of these channels leading to loss of ionic homeostasis and cell death.

Rapamycin protects the mitochondria against oxidative stress and apoptosis in a rat model of Parkinson's disease.

PubMed

Jiang, Jianhua; Jiang, Juean; Zuo, Yuanyi; Gu, Zhenlun

2013-04-01

Parkinson's disease (PD) is a neurodegenerative disease, in which oxidative stress and mitochondrial dysfunction are responsible for neuronal apoptosis. Rapamycin plays a crucial role in reducing oxidative stress and protecting the mitochondria. However, its protective role in PD has not yet been fully elucidated. In this study, we report that pre-treatment with rapamycin provides behavioral improvements, protects against the loss of dopaminergic neurons, and alleviates mitochondrial ultrastructural injuries in a rat model of PD. Peroxide levels were lower and antioxidant activities were higher in PD rats pre-treated with rapamycin compared to the PD rats pre-treated with the vehicle. Furthermore, pre-treatment with rapamycin significantly elevated the expression of anti-apoptotic markers and reduced the levels of pro-apoptotic markers compared to pre-treatment with the vehicle. In conclusion, our results demonstrated that rapamycin reduced oxidative stress and alleviated mitochondrial injuries in the 6-hydroxydopamine (6-OHDA)-induced rat model of PD, which may subsequently contribute to its anti-apoptotic effects. The ability of rapamycin to exhibit neuroprotection in a rat model of PD may be related to its antioxidant capabilities.

Curcumin prevents mitochondrial dysfunction in the brain of the senescence-accelerated mouse-prone 8.

PubMed

Eckert, Gunter P; Schiborr, Christina; Hagl, Stephanie; Abdel-Kader, Reham; Müller, Walter E; Rimbach, Gerald; Frank, Jan

2013-04-01

The aging brain suffers mitochondrial dysfunction and a reduced availability of energy in the form of ATP, which in turn may cause or promote the decline in cognitive, sensory, and motor function observed with advancing age. There is a need for animal models that display some of the pathological features of human brain aging in order to study their prevention by e.g. dietary factors. We thus investigated the suitability of the fast-aging senescence-accelerated mouse-prone 8 (SAMP8) strain and its normally aging control senescence-accelerated mouse-resistant 1 (SAMR1) as a model for the age-dependent changes in mitochondrial function in the brain. To this end, 2-months old male SAMR1 (n=10) and SAMP8 mice (n=7) were fed a Western type diet (control groups) for 5months and one group of SAMP8 mice (n=6) was fed an identical diet fortified with 500mg curcumin per kg. Dissociated brain cells and brain tissue homogenates were analyzed for malondialdehyde, heme oxygenase-1 mRNA, mitochondrial membrane potential (MMP), ATP concentrations, protein levels of mitochondrial marker proteins for mitochondrial membranes (TIMM, TOMM), the mitochondrial permeability transition pore (ANT1, VDAC1, TSPO), respiration complexes, and fission and fusion (Fis, Opa1, Mfn1, Drp1). Dissociated brain cells isolated from SAMP8 mice showed significantly reduced MMP and ATP levels, probably due to significantly diminished complex V protein expression, and increased expression of TSPO. Fission and fusion marker proteins indicate enhanced mitochondrial fission in brains of SAMP8 mice. Treatment of SAMP8 mice with curcumin improved MMP and ATP and restored mitochondrial fusion, probably by up-regulating nuclear factor PGC1α protein expression. In conclusion, SAMP8 compared to SAMR1 mice are a suitable model to study age-dependent changes in mitochondrial function and curcumin emerges as a promising nutraceutical for the prevention of neurodegenerative diseases that are accompanied or caused by mitochondrial dysfunction. Copyright © 2013 Elsevier Ltd. All rights reserved.

A specific amino acid formula prevents alcoholic liver disease in rodents.

PubMed

Tedesco, Laura; Corsetti, Giovanni; Ruocco, Chiara; Ragni, Maurizio; Rossi, Fabio; Carruba, Michele O; Valerio, Alessandra; Nisoli, Enzo

2018-05-01

Chronic alcohol consumption promotes mitochondrial dysfunction, oxidative stress, defective protein metabolism, and fat accumulation in hepatocytes (liver steatosis). Inadequate amino acid metabolism is worsened by protein malnutrition, frequently present in alcohol-consuming patients, with reduced circulating branched-chain amino acids (BCAAs). Here we asked whether dietary supplementation with a specific amino acid mixture, enriched in BCAAs (BCAAem) and able to promote mitochondrial function in muscle of middle-aged rodents, would prevent mitochondrial dysfunction and liver steatosis in Wistar rats fed on a Lieber-DeCarli ethanol (EtOH)-containing liquid diet. Supplementation of BCAAem, unlike a mixture based on the amino acid profile of casein, abrogated the EtOH-induced fat accumulation, mitochondrial impairment, and oxidative stress in liver. These effects of BCAAem were accompanied by normalization of leucine, arginine, and tryptophan levels, which were reduced in liver of EtOH-consuming rats. Moreover, although the EtOH exposure of HepG2 cells reduced mitochondrial DNA, mitochondrial transcription factors, and respiratory chain proteins, the BCAAem but not casein-derived amino acid supplementation halted this mitochondrial toxicity. Nicotinamide adenine dinucleotide levels and sirtuin 1 (Sirt1) expression, as well as endothelial nitric oxide (eNOS) and mammalian/mechanistic target of rapamycin (mTOR) signaling pathways, were downregulated in the EtOH-exposed HepG2 cells. BCAAem reverted these molecular defects and the mitochondrial dysfunction, suggesting that the mitochondrial integrity obtained with the amino acid supplementation could be mediated through a Sirt1-eNOS-mTOR pathway. Thus a dietary activation of the mitochondrial biogenesis and function by a specific amino acid supplement protects against the EtOH toxicity and preserves the liver integrity in mammals. NEW & NOTEWORTHY Dietary supplementation of a specific amino acid formula prevents both fat accumulation and mitochondrial dysfunction in hepatocytes of alcohol-consuming rats. These effects are accompanied also by increased expression of anti-reactive oxygen species genes. The amino acid-protective effects likely reflect activation of sirtuin 1-endothelial nitric oxide synthase-mammalian target of rapamycin pathway able to regulate the cellular energy balance of hepatocytes exposed to chronic, alcoholic damage.

Differential acute and chronic effects of burn trauma on murine skeletal muscle bioenergetics

PubMed Central

Porter, Craig; Herndon, David N.; Bhattarai, Nisha; Ogunbileje, John O.; Szczesny, Bartosz; Szabo, Csaba; Toliver-Kinsky, Tracy; Sidossis, Labros S.

2015-01-01

Altered skeletal muscle mitochondrial function contributes to the pathophysiological stress response to burns. However, the acute and chronic impact of burn trauma on skeletal muscle bioenergetics remains poorly understood. Here, we determined the temporal relationship between burn trauma and mitochondrial function in murine skeletal muscle local to and distal from burn wounds. Male BALB/c mice (8–10 weeks old) were burned by submersion of the dorsum in water (~95°C) to create a full thickness burn on ~30% of the body. Skeletal muscle was harvested from spinotrapezius underneath burn wounds (local) and the quadriceps (distal) of sham and burn treated mice at 3h, 24h, 4d and 10d post-injury. Mitochondrial respiration was determined in permeabilized myofiber bundles by high-resolution respirometry. Caspase 9 and caspase 3 protein concentration were determined by western blot. In muscle local to burn wounds, respiration coupled to ATP production was significantly diminished at 3h and 24h post-injury (P<0.001), as was mitochondrial coupling control (P<0.001). There was a 5- (P<0.05) and 8-fold (P<0.001) increase in respiration in response to cytochrome at 3h and 24h post burn, indicating damage to the outer mitochondrial membranes. Moreover, we also observed greater active caspase 9 and caspase 3 in muscle local to burn wounds, indicating the induction of apoptosis. Distal muscle mitochondrial function was unaltered by burn trauma until 10d post burn, where both respiratory capacity (P<0.05) and coupling control (P<0.05) was significantly lower than sham. These data highlight a differential response in muscle mitochondrial function to burn trauma, where the timing, degree and mode of dysfunction are dependent on whether the muscle is local or distal to the burn wound. PMID:26615714

Resuscitation Strategies for Burn Injuries Sustained in Austere Environments to Improve Renal Perfusion and Function

DTIC Science & Technology

2017-10-01

a synergistic effect with systemic in- flammation and manifests in several physiological impairments (hy- perglycemia, elevated body temperature ...based on respirometry (i.e., the ratio of mitochondrial oxygen consumption in the presence and absence of ADP), mitochondrial function was reported to be...we predict it will not be as effective as the gold standard i.v. fluid resuscitation which may relate to fluid volume requirements that cannot be

Flavonoid Fraction of Orange and Bergamot Juices Protect Human Lung Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Stress

PubMed Central

Ferlazzo, Nadia; Visalli, Giuseppa; Smeriglio, Antonella; Cirmi, Santa; Lombardo, Giovanni Enrico; Campiglia, Pietro; Di Pietro, Angela

2015-01-01

It has been reported that oxidant/antioxidant imbalance triggers cell damage that in turn causes a number of lung diseases. Flavonoids are known for their health benefits, and Citrus fruits juices are one of the main food sources of these secondary plant metabolites. The present study was designed to evaluate the effect of the flavonoid fraction of bergamot and orange juices, on H2O2-induced oxidative stress in human lung epithelial A549 cells. First we tested the antioxidant properties of both extracts in cell-free experimental models and then we assayed their capability to prevent the cytotoxic effects induced by H2O2. Our results demonstrated that both Citrus juice extracts reduce the generation of reactive oxygen species and membrane lipid peroxidation, improve mitochondrial functionality, and prevent DNA-oxidative damage in A549 cells incubated with H2O2. Our data indicate that the mix of flavonoids present in both bergamot and orange juices may be of use in preventing oxidative cell injury and pave the way for further research into a novel healthy approach to avoid lung disorders. PMID:26221182

Flavonoid Fraction of Orange and Bergamot Juices Protect Human Lung Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Stress.

PubMed

Ferlazzo, Nadia; Visalli, Giuseppa; Smeriglio, Antonella; Cirmi, Santa; Lombardo, Giovanni Enrico; Campiglia, Pietro; Di Pietro, Angela; Navarra, Michele

2015-01-01

It has been reported that oxidant/antioxidant imbalance triggers cell damage that in turn causes a number of lung diseases. Flavonoids are known for their health benefits, and Citrus fruits juices are one of the main food sources of these secondary plant metabolites. The present study was designed to evaluate the effect of the flavonoid fraction of bergamot and orange juices, on H2O2-induced oxidative stress in human lung epithelial A549 cells. First we tested the antioxidant properties of both extracts in cell-free experimental models and then we assayed their capability to prevent the cytotoxic effects induced by H2O2. Our results demonstrated that both Citrus juice extracts reduce the generation of reactive oxygen species and membrane lipid peroxidation, improve mitochondrial functionality, and prevent DNA-oxidative damage in A549 cells incubated with H2O2. Our data indicate that the mix of flavonoids present in both bergamot and orange juices may be of use in preventing oxidative cell injury and pave the way for further research into a novel healthy approach to avoid lung disorders.

Mitochondrial Dysregulation and Protection in Cisplatin Nephrotoxicity

PubMed Central

Yang, Yuan; Liu, Hong; Liu, Fuyou; Dong, Zheng

2014-01-01

Nephrotoxicity is a major side effect of cisplatin in chemotherapy. Pathologically, cisplatin nephrotoxicity is characterized by cell injury and death in renal tubules. The research in the past decade has gained significant understanding of the cellular and molecular mechanisms of tubular cell death, revealing a central role of mitochondrial dysregulation. The pathological changes of mitochondria in cisplatin nephrotoxicity are mainly triggered by DNA damage response, pro-apoptotic protein attack, disruption of mitochondrial dynamics, and oxidative stress. As such, inhibitory strategies targeting these cytotoxic events may provide renal protection. Nonetheless, ideal approaches for renoprotection should not only protect kidneys but also enhance the anti-cancer efficacy of cisplatin in chemotherapy. PMID:24859930

Early spinal cord and brainstem involvement in infantile Leigh syndrome possibly caused by a novel variant.

PubMed

Tenney, Jeffrey R; Prada, Carlos E; Hopkin, Robert J; Hallinan, Barbara E

2013-12-01

Leigh syndrome, due to a dysfunction of mitochondrial energy metabolism, is a genetically heterogeneous and progressive neurologic disorder that usually occurs in infancy and childhood. Its clinical presentation and neuroimaging findings can be variable, especially early in the course of the disease. This report presents a patient with infantile Leigh syndrome who had atypical radiologic findings on serial neuroimaging studies with early and severe involvement of the cervical spinal cord and brainstem and injury to the thalami and basal ganglia occurring only late in the clinical course. Postmortem microscopic examination supported this timing of injury within the central nervous system. In addition, mitochondrial deoxyribonucleic acid sequencing showed a novel homoplasmic variant that could be responsible for this unique lethal form of Leigh syndrome.

Role of Pterocarpus santalinus against mitochondrial dysfunction and membrane lipid changes induced by ulcerogens in rat gastric mucosa.

PubMed

Narayan, Shoba; Devi, R S; Devi, C S Shyamala

2007-11-20

Free radicals produced by ulcerogenic agents affect the TCA cycle enzymes located in the outer membrane of the mitochondria. Upon induction with ulcerogens, peroxidation of membrane lipids bring about alterations in the mitochondrial enzyme activity. This indicates an increase in the permeability levels of the mitochondrial membrane. The ability of PSE to scavenge the reactive oxygen species results in restoration of activities of TCA cycle enzymes. NSAIDs interfere with the mitochondrial beta-oxidation of fatty acids in vitro and in vivo, resulting in uncoupling of mitochondrial oxidative phosphorylation process. This usually results in diminished cellular ATP production. The recovery of gastric mucosal barrier function through maintenance of energy metabolism results in maintenance of ATP levels, as observed in this study upon treatment with PSE. Membrane integrity altered by peroxidation is known to have a modified fatty acid composition, a disruption of permeability, a decrease in electrical resistance, and increase in flip-flopping between monolayers and inactivated cross-linked proteins. The severe depletion of arachidonic acid in ulcer induced groups was prevented upon treatment with PSE. The acid inhibitory property of the herbal extract enables the maintenance of GL activity upon treatment with PSE. The ability to prevent membrane peroxidation has been traced to the presence of active constituents in the PSE. In essence, PSE has been found to prevent mitochondrial dysfunction, provide mitochondrial cell integrity, through the maintenance of lipid bilayer by its ability to provide a hydrophobic character to the gastric mucosa, further indicating its ability to reverse the action of NSAIDs and mast cell degranulators in gastric mucosa.

Prevention of alcoholic fatty liver and mitochondrial dysfunction in the rat by long-chain polyunsaturated fatty acids

PubMed Central

Song, Byoung-Joon; Moon, Kwan-Hoon; Olsson, Nils U.; Salem, Norman

2008-01-01

Background/Aims We reported that reduced dietary intake of polyunsaturated fatty acids (PUFA) such as arachidonic (AA,20:4n6, omega-6) and docosahexaenoic (DHA,22:6n3, omega-3) acids led to alcohol-induced fatty liver and fibrosis. This study was aimed at studying the mechanisms by which a DHA/AA-supplemented diet prevents alcohol-induced fatty liver. Methods Male Long-Evans rats were fed an ethanol or control liquid-diet with or without DHA/AA for 9 weeks. Plasma transaminase levels, liver histology, oxidative/nitrosative stress markers, and activities of oxidatively-modified mitochondrial proteins were evaluated. Results Chronic alcohol administration increased the degree of fatty liver but fatty liver decreased significantly in rats fed the alcohol-DHA/AA-supplemented diet. Alcohol exposure increased oxidative/nitrosative stress with elevated levels of ethanol-inducible CYP2E1, nitric oxide synthase, nitrite and mitochondrial hydrogen peroxide. However, these increments were normalized in rats fed the alcohol-DHA/AA-supplemented diet. The number of oxidatively-modified mitochondrial proteins was markedly increased following alcohol exposure but significantly reduced in rats fed the alcohol-DHA/AA-supplemented diet. The suppressed activities of mitochondrial aldehyde dehydrogenase, ATP synthase, and 3-ketoacyl-CoA thiolase in ethanol-exposed rats were also recovered in animals fed the ethanol-DHA/AA-supplemented diet. Conclusions Addition of DHA/AA prevents alcohol-induced fatty liver and mitochondrial dysfunction in an animal model by protecting various mitochondrial enzymes most likely through reducing oxidative/nitrosative stress. PMID:18571270

Optical imaging of irradiated and non-irradiated hearts (Conference Presentation)

NASA Astrophysics Data System (ADS)

Bolin, Stephanie; Chen, Guanchu; Medhora, Meetha M.; Camara, Amadou K. S.; Ranji, Mahsa

2016-03-01

Objective: In this study, the metabolic state of the heart tissue is studied in a rodent model of ischemia and reperfusion (IR) in rats exposed to irradiation injury using a cryofluorescence imaging technique. Mitochondrial metabolic state is evaluated by autofluorescence of mitochondrial metabolic coenzymes NADH and FAD. The redox ratio (NADH/FAD) is used as a biochemical/metabolic marker of oxidative stress, before, during and after IR. Materials and methods: Hearts were extracted from non-irradiated (control) and irradiated rats (Irr) given 15 Gy whole thorax irradiation rats (WTI). After 35 days, before the onset of radiation pneumonitis, these two groups of hearts were subjected to one of three treatments; Time control (TC; hearts perfused for the duration of the protocol without ischemia or IR), 25 minutes ischemia with no reperfusion and 25 minutes ischemia followed by 60 minutes reperfusion (IR). Hearts were removed from the Langendorff perfusion system and immediately snap frozen in liquid N2 to preserve the metabolic state after injury; 3-dimensional (3D) cryo-fluorescent imager was used to obtain in fixed time NADH and FAD fluorescence images and their distribution across the entire ventricles. In this study, a 30-μm axial resolution was used resulting in 550 cross-section images per heart. The 3D images of the redox ratio and their respective histograms were calculated in the six groups of hearts. Results: We compared the mean values of the redox ratio in each group, which demonstrate a reduced mitochondrial redox state in both irradiated and non-irradiated ischemic hearts and an oxidized mitochondrial redox state for both irradiated and non-irradiated ischemia-reperfusion hearts compared to control hearts. For non-irradiated hearts, ischemia and IR injuries resulted respectively in 61% increase and 54% decrease in redox ratio when compared with TC. For irradiated hearts, ischemia and IR injuries resulted respectively in 90% increase and 50% decrease in redox ratio when compared to TC. Conclusion: The cryoimager is able to quantify ischemia and IR injuries. Cryoimaging is a unique 3D imaging tools that provides quantitative measurement of tissue metabolic state. Hearts that underwent irradiation indicates a more oxidized metabolic state in the tissue. This change persists across all three treatments.

Paracrine Activation of the Wnt/β-Catenin Pathway by Bone Marrow Stem Cell Attenuates Cisplatin-Induced Kidney Injury.

PubMed

Jiao, Xiaoyan; Cai, Jieru; Yu, Xiaofang; Ding, Xiaoqiang

2017-01-01

Cisplatin-induced acute kidney injury (AKI) involves damage to tubular cells via excess reactive oxygen species (ROS) generation. Stem cell-based therapies have shown great promise in AKI treatment. In this study, we aimed to assess the protective effect and mechanism of bone marrow mesenchymal stem cell (BMSC)-derived conditioned medium (CM) against cisplatin-induced AKI. In vitro, NRK-52E cells were incubated with cisplatin in the presence or absence of CM, followed by the assessment of cell viability, apoptosis and cell cycle distribution. Then, ICG-001 and IWR-1 were used to inhibit the wnt/β-catenin pathway. Furthermore, intracellular and mitochondrial ROS levels were evaluated using DCFH-DA and MitoSOX, respectively. In vivo, after cisplatin injection, rats were intravenously injected with CM or BMSCs. Sera and kidney tissues were collected on day 3 after cisplatin injection to evaluate changes in renal function and histology. Western blotting and qRT-PCR were employed to determine the expression of wnt/β-catenin pathway-related genes and proteins. Immunohistochemical staining was used to evaluate tubular β-catenin expression in kidney biopsy from AKI patients. CM protected NRK-52E cells from cisplatin-induced injury by restoring the wnt4/β-catenin pathway. In response to ICG-001 and IWR-1, the protective effect of CM was attenuated, characterized by a decrease in cell proliferation and an increase in cell apoptosis and intracellular and mitochondrial ROS levels. Knockdown of β-catenin using siRNAs also suppressed the mitochondrial biogenesis regulators PGC-1α, TFAM and NRF-1. In the rat model, CM significantly alleviated renal function and histology associated with tubular injury and upregulated wnt4 and β-catenin. However, the renoprotective effect of CM was blocked by ICG-001, characterized by exacerbated renal function, suppressed PGC-1α expression and increased mitochondrial ROS. Clinical data showed that the tubular β-catenin level was lower in AKI patients experiencing partial recovery than in patients experiencing complete recovery. The activation of the wnt/β-catenin pathway by CM protects against cisplatin-induced kidney injury, resulting in reduced apoptosis and intracellular ROS levels. © 2017 The Author(s). Published by S. Karger AG, Basel.

Injuries in the military: a review and commentary focused on prevention.

PubMed

Jones, B H; Perrotta, D M; Canham-Chervak, M L; Nee, M A; Brundage, J F

2000-04-01

In November 1996, the Armed Forces Epidemiological Board (AFEB) Injury Prevention and Control Work Group issued a report that cited injuries as the leading cause of morbidity and mortality among military service members. This article reviews the types and categories of military morbidity and mortality data examined by the AFEB work group and the companion Department of Defense (DoD) Injury Surveillance and Prevention Work Group. This article further uses the injury data reviewed to illustrate the role of surveillance and research in injury prevention. The review provides the context for discussion of the implications of the AFEB work group's findings for the prevention of injuries in the military. The AFEB work group consisted of 11 civilian injury epidemiologists, health professionals and scientists from academia, and other non-DoD government agencies, plus six military liaison officers. Injury data from medical databases were provided to the civilian experts on the AFEB work group by the all-military DoD Injury Surveillance and Prevention Work Group. The AFEB work group assessed the value of each database to the process of prevention and made recommendations for improvement and use of each data source. Both work groups found that injuries were the single leading cause of deaths, disabilities, hospitalizations, outpatient visits, and manpower losses among military service members. They also identified numerous data sources useful for determining the causes and risk factors for injuries. Those data sources indicate that training injuries, sports, falls, and motor vehicle crashes are among the most important causes of morbidity for military personnel. While the work group recommends ways to prevent injuries, they felt the top priority for injury prevention must be the formation of a comprehensive medical surveillance system. Data from this surveillance system must be used routinely to prioritize and monitor injury and disease prevention and research programs. The success of injury prevention will depend not just on use of surveillance but also partnerships among the medical, surveillance, and safety agencies of the military services as well as the military commanders, other decision makers, and service members whose direct actions can prevent injuries and disease.

Cold ischemia contributes to the development of chronic rejection and mitochondrial injury after cardiac transplantation.

PubMed

Schneeberger, Stefan; Amberger, Albert; Mandl, Julia; Hautz, Theresa; Renz, Oliver; Obrist, Peter; Meusburger, Hugo; Brandacher, Gerald; Mark, Walter; Strobl, Daniela; Troppmair, Jakob; Pratschke, Johann; Margreiter, Raimund; Kuznetsov, Andrey V

2010-12-01

Chronic rejection (CR) remains an unsolved hurdle for long-term heart transplant survival. The effect of cold ischemia (CI) on progression of CR and the mechanisms resulting in functional deficit were investigated by studying gene expression, mitochondrial function, and enzymatic activity. Allogeneic (Lew→F344) and syngeneic (Lew→Lew) heart transplantations were performed with or without 10 h of CI. After evaluation of myocardial contraction, hearts were excised at 2, 10, 40, and 60 days for investigation of vasculopathy, gene expression, enzymatic activities, and mitochondrial respiration. Gene expression studies identified a gene cluster coding for subunits of the mitochondrial electron transport chain regulated in response to CI and CR. Myocardial performance, mitochondrial function, and mitochondrial marker enzyme activities declined in all allografts with time after transplantation. These declines were more rapid and severe in CI allografts (CR-CI) and correlated well with progression of vasculopathy and fibrosis. Mitochondria related gene expression and mitochondrial function are substantially compromised with the progression of CR and show that CI impacts on progression, gene profile, and mitochondrial function of CR. Monitoring mitochondrial function and enzyme activity might allow for earlier detection of CR and cardiac allograft dysfunction. © 2010 The Authors. Journal compilation © 2010 European Society for Organ Transplantation.

Combination strategy of PARP inhibitor with antioxidant prevent bioenergetic deficits and inflammatory changes in CCI-induced neuropathy.

PubMed

Komirishetty, Prashanth; Areti, Aparna; Gogoi, Ranadeep; Sistla, Ramakrishna; Kumar, Ashutosh

2017-02-01

Neuropathic pain, a debilitating pain condition and the underlying pathogenic mechanisms are complex and interwoven amongst each other and still there is scant information available regarding therapies which promise to treat the condition. Evidence indicate that oxidative/nitrosative stress induced poly (ADP-ribose) polymerase (PARP) overactivation initiate neuroinflammation and bioenergetic crisis culminating into neurodegenerative changes following nerve injury. Hence, we investigated the therapeutic effect of combining an antioxidant, quercetin and a PARP inhibitor, 4-amino 1, 8-naphthalimide (4-ANI) on the hallmark deficits induced by chronic constriction injury (CCI) of sciatic nerve in rats. Quercetin (25 mg/kg, p.o.) and 4-ANI (3 mg/kg, p.o.) were administered either alone or in combination for 14 days to examine sciatic functional index, allodynia and hyperalgesia using walking track analysis, Von Frey, acetone spray and hot plate tests respectively. Malondialdehyde, nitrite and glutathione levels were estimated to detect oxidative/nitrosative stress; mitochondrial membrane potential and cytochrome c oxidase activity to assess mitochondrial function; NAD & ATP levels to examine the bioenergetic status and levels of inflammatory markers were evaluated in ipsilateral sciatic nerve. Quercetin and 4-ANI alone improved the pain behaviour and biochemical alterations but the combination therapy demonstrated an appreciable reversal of CCI-induced changes. Nitrotyrosine and Poly ADP-Ribose (PAR) immunopositivity was decreased and nuclear factor erythroid 2-related factor (Nrf-2) levels were increased significantly in micro-sections of the sciatic nerve and dorsal root ganglion (DRG) of treatment group. These results suggest that simultaneous inhibition of oxidative stress-PARP activation cascade may potentially be useful strategies for management of trauma induced neuropathic pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carvedilol prevents functional deficits in peripheral nerve mitochondria of rats with oxaliplatin-evoked painful peripheral neuropathy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Areti, Aparna; Komirishetty, Prashanth; Kumar, Ash

Oxaliplatin use as chemotherapeutic agent is frequently limited by cumulative neurotoxicity which may compromise quality of life. Reports relate this neurotoxic effect to oxidative stress and mitochondrial dysfunction in peripheral nerves and dorsal root ganglion (DRG). Carvedilol is an antihypertensive drug, has also been appreciated for its antioxidant and mitoprotective properties. Carvedilol co-treatment did not reduce the anti-tumor effects of oxaliplatin in human colon cancer cells (HT-29), but exhibited free radical scavenging activity against oxaliplatin-induced oxidative stress in neuronal cells (Neuro-2a). Hence, the present study was designed to investigate the effect of carvedilol in the experimental model of oxaliplatin-induced peripheralmore » neuropathy (OIPN) in Sprague-Dawley rats. Oxaliplatin reduced the sensory nerve conduction velocity and produced the thermal and mechanical nociception. Carvedilol significantly (P < 0.001) attenuated these functional and sensorimotor deficits. It also counteracted oxidative/nitrosative stress by reducing the levels of nitrotyrosine and improving the mitochondrial superoxide dismutase expression in both sciatic nerve and DRG tissues. It improved the mitochondrial function and prevented the oxaliplatin-induced alteration in mitochondrial membrane potential in sciatic nerve thus prevented loss of intra epidermal nerve fiber density in the foot pads. Together the results prompt the use of carvedilol along with chemotherapy with oxaliplatin to prevent the peripheral neuropathy. - Graphical abstract: Schematic representation neuroprotective mechanisms of carvedilol in oxaliplatin-induced peripheral neuropathy. - Highlights: • Oxaliplatin-induced mitochondrial dysfunction causes neurotoxicity. • Mitochondrial dysfunction leads to bioenergetic and functional deficits. • Carvedilol alleviated oxaliplatin-induced behavioural and functional changes. • Targeting mitochondria with carvedilol attenuated neuropathic pain.« less

A Peculiar Formula of Essential Amino Acids Prevents Rosuvastatin Myopathy in Mice

PubMed Central

D'Antona, Giuseppe; Tedesco, Laura; Ruocco, Chiara; Corsetti, Giovanni; Ragni, Maurizio; Fossati, Andrea; Saba, Elisa; Fenaroli, Francesca; Montinaro, Mery; Carruba, Michele O.; Valerio, Alessandra

2016-01-01

Abstract Aims: Myopathy, characterized by mitochondrial oxidative stress, occurs in ∼10% of statin-treated patients, and a major risk exists with potent statins such as rosuvastatin (Rvs). We sought to determine whether a peculiar branched-chain amino acid-enriched mixture (BCAAem), found to improve mitochondrial function and reduce oxidative stress in muscle of middle-aged mice, was able to prevent Rvs myopathy. Results: Dietary supplementation of BCAAem was able to prevent the structural and functional alterations of muscle induced by Rvs in young mice. Rvs-increased plasma 3-methylhistidine (a marker of muscular protein degradation) was prevented by BCAAem. This was obtained without changes of Rvs ability to reduce cholesterol and triglyceride levels in blood. Rather, BCAAem promotes de novo protein synthesis and reduces proteolysis in cultured myotubes. Morphological alterations of C2C12 cells induced by statin were counteracted by amino acids, as were the Rvs-increased atrogin-1 mRNA and protein levels. Moreover, BCAAem maintained mitochondrial mass and density and citrate synthase activity in skeletal muscle of Rvs-treated mice beside oxygen consumption and ATP levels in C2C12 cells exposed to statin. Notably, BCAAem assisted Rvs to reduce oxidative stress and to increase the anti-reactive oxygen species (ROS) defense system in skeletal muscle. Innovation and Conclusions: The complex interplay between proteostasis and antioxidant properties may underlie the mechanism by which a specific amino acid formula preserves mitochondrial efficiency and muscle health in Rvs-treated mice. Strategies aimed at promoting protein balance and controlling mitochondrial ROS level may be used as therapeutics for the treatment of muscular diseases involving mitochondrial dysfunction, such as statin myopathy. Antioxid. Redox Signal. 25, 595–608. PMID:27245589

Mitochondrial transfer of mesenchymal stem cells effectively protects corneal epithelial cells from mitochondrial damage.

PubMed

Jiang, Dan; Gao, Fei; Zhang, Yuelin; Wong, David Sai Hung; Li, Qing; Tse, Hung-Fat; Xu, Goufeng; Yu, Zhendong; Lian, Qizhou

2016-11-10

Recent studies have demonstrated that mesenchymal stem cells (MSCs) can donate mitochondria to airway epithelial cells and rescue mitochondrial damage in lung injury. We sought to determine whether MSCs could donate mitochondria and protect against oxidative stress-induced mitochondrial dysfunction in the cornea. Co-culturing of MSCs and corneal epithelial cells (CECs) indicated that the efficiency of mitochondrial transfer from MSCs to CECs was enhanced by Rotenone (Rot)-induced oxidative stress. The efficient mitochondrial transfer was associated with increased formation of tunneling nanotubes (TNTs) between MSCs and CECs, tubular connections that allowed direct intercellular communication. Separation of MSCs and CECs by a transwell culture system revealed no mitochiondrial transfer from MSCs to CECs and mitochondrial function was impaired when CECs were exposed to Rot challenge. CECs with or without mitochondrial transfer from MSCs displayed a distinct survival capacity and mitochondrial oxygen consumption rate. Mechanistically, increased filopodia outgrowth in CECs for TNT formation was associated with oxidative inflammation-activated NFκB/TNFαip2 signaling pathways that could be attenuated by reactive oxygen species scavenger N-acetylcysteine (NAC) treatment. Furthermore, MSCs grown on a decellularized porcine corneal scaffold were transplanted onto an alkali-injured eye in a rabbit model. Enhanced corneal wound healing was evident following healthy MSC scaffold transplantation. And transferred mitochondria was detected in corneal epithelium. In conclusion, mitochondrial transfer from MSCs provides novel protection for the cornea against oxidative stress-induced mitochondrial damage. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.

Mitochondrial NUDIX hydrolases: A metabolic link between NAD catabolism, GTP and mitochondrial dynamics.

PubMed

Long, Aaron; Klimova, Nina; Kristian, Tibor

2017-10-01

NAD + catabolism and mitochondrial dynamics are important parts of normal mitochondrial function and are both reported to be disrupted in aging, neurodegenerative diseases, and acute brain injury. While both processes have been extensively studied there has been little reported on how the mechanisms of these two processes are linked. This review focuses on how downstream NAD + catabolism via NUDIX hydrolases affects mitochondrial dynamics under pathologic conditions. Additionally, several potential targets in mitochondrial dysfunction and fragmentation are discussed, including the roles of mitochondrial poly(ADP-ribose) polymerase 1(mtPARP1), AMPK, AMP, and intra-mitochondrial GTP metabolism. Mitochondrial and cytosolic NUDIX hydrolases (NUDT9α and NUDT9β) can affect mitochondrial and cellular AMP levels by hydrolyzing ADP- ribose (ADPr) and subsequently altering the levels of GTP and ATP. Poly (ADP-ribose) polymerase 1 (PARP1) is activated after DNA damage, which depletes NAD + pools and results in the PARylation of nuclear and mitochondrial proteins. In the mitochondria, ADP-ribosyl hydrolase-3 (ARH3) hydrolyzes PAR to ADPr, while NUDT9α metabolizes ADPr to AMP. Elevated AMP levels have been reported to reduce mitochondrial ATP production by inhibiting the adenine nucleotide translocase (ANT), allosterically activating AMPK by altering the cellular AMP: ATP ratio, and by depleting mitochondrial GTP pools by being phosphorylated by adenylate kinase 3 (AK3), which uses GTP as a phosphate donor. Recently, activated AMPK was reported to phosphorylate mitochondria fission factor (MFF), which increases Drp1 localization to the mitochondria and promotes mitochondrial fission. Moreover, the increased AK3 activity could deplete mitochondrial GTP pools and possibly inhibit normal activity of GTP-dependent fusion enzymes, thus altering mitochondrial dynamics. Published by Elsevier Ltd.

Female soccer knee injury: observed knowledge gaps in injury prevention among players/parents/coaches and current evidence (the KNOW study).

PubMed

Orr, B; Brown, C; Hemsing, J; McCormick, T; Pound, S; Otto, D; Emery, C A; Beaupre, L A

2013-06-01

This study sought to determine if knowledge regarding the risk for knee injuries and the potential for their prevention is being translated to female adolescent soccer players (13-18 years), their parents, and coaches. Eligible participants in the 2007 indoor soccer season were surveyed to determine their knowledge of the risk for and the potential to prevent knee injuries, and their knowledge of effective prevention strategies, if they felt that injury prevention was possible. Team selection was stratified to be representative of both competitive and recreational level play and age group distributions within the selected soccer association. Of the study subjects, 773/1396 (55.4%) responded to the survey: 408 (53%) players, 292 (38%) parents, and 73 (9%) coaches. Most respondents (538 [71%]) were aware of the risk for knee injury. Coaches and parents were more likely than players to view knee injuries as preventable; however, appropriate prevention strategies were often not identified. Four hundred eighty-four (63.8%) respondents reported that they had never received information on knee injuries. Substantial knowledge gaps regarding knee injury prevention and effective preventative strategies were identified. Given the predominance of knee injuries in female adolescent soccer players, there is an urgent need for knowledge translation of prevention strategies to decrease both incidence and long-term consequences of knee injuries. © 2011 John Wiley & Sons A/S.

Microparticles Mediate Hepatic Ischemia-Reperfusion Injury and Are the Targets of Diannexin (ASP8597)

PubMed Central

Wong, Heng Jian; Croft, Kevin; Mori, Trevor; Farrell, Geoffrey C.

2014-01-01

Background & Aims Ischemia–reperfusion injury (IRI) can cause hepatic failure after liver surgery or transplantation. IRI causes oxidative stress, which injures sinusoidal endothelial cells (SECs), leading to recruitment and activation of Kupffer cells, platelets and microcirculatory impairment. We investigated whether injured SECs and other cell types release microparticles during post-ischemic reperfusion, and whether such microparticles have pro-inflammatory, platelet-activating and pro-injurious effects that could contribute to IRI pathogenesis. Methods C57BL6 mice underwent 60 min of partial hepatic ischemia followed by 15 min–24 hrs of reperfusion. We collected blood and liver samples, isolated circulating microparticles, and determined protein and lipid content. To establish mechanism for microparticle production, we subjected murine primary hepatocytes to hypoxia-reoxygenation. Because microparticles express everted phosphatidylserine residues that are the target of annexin V, we analyzed the effects of an annexin V-homodimer (Diannexin or ASP8597) on post-ischemia microparticle production and function. Results Microparticles were detected in the circulation 15–30 min after post-ischemic reperfusion, and contained markers of SECs, platelets, natural killer T cells, and CD8+ cells; 4 hrs later, they contained markers of macrophages. Microparticles contained F2-isoprostanes, indicating oxidative damage to membrane lipids. Injection of mice with TNF-α increased microparticle formation, whereas Diannexin substantially reduced microparticle release and prevented IRI. Hypoxia-re-oxygenation generated microparticles from primary hepatocytes by processes that involved oxidative stress. Exposing cultured hepatocytes to preparations of microparticles isolated from the circulation during IRI caused injury involving mitochondrial membrane permeability transition. Microparticles also activated platelets and induced neutrophil migration in vitro. The inflammatory properties of microparticles involved activation of NF-κB and JNK, increased expression of E-selectin, P-selectin, ICAM-1 and VCAM-1. All these processes were blocked by coating microparticles with Diannexin. Conclusions Following hepatic IRI, microparticles circulate and can be taken up by hepatocytes, where they activate signaling pathways that mediate inflammation and hepatocyte injury. Diannexin prevents microparticle formation and subsequent inflammation. PMID:25222287

The effect of alpha-lipoic acid on mitochondrial superoxide and glucocorticoid-induced hypertension.

PubMed

Ong, Sharon L H; Vohra, Harpreet; Zhang, Yi; Sutton, Matthew; Whitworth, Judith A

2013-01-01

To examine the effect of alpha-lipoic acid, an antioxidant with mitochondrial superoxide inhibitory properties, on adrenocorticotrophic hormone- (ACTH-HT) and dexamethasone-induced hypertensions (DEX-HT) in rats and if any antihypertensive effect is mediated via mitochondrial superoxide inhibition. In a prevention study, rats received ground food or alpha-lipoic-acid-laced food (10 mg/rat/day) for 15 nights. Saline, adrenocorticotrophic hormone (ACTH, 0.2 mg/kg/day), or dexamethasone (DEX, 10  μ g/rat/day) was injected subcutaneously from day 5 to day 11. In a reversal study, rats received alpha-lipoic-acid-laced food 4 days after commencement of saline or DEX. Tail-cuff systolic blood pressure (SBP) was measured second daily. Kidney mitochondrial superoxide was examined using (MitoSOX) Red (MitoSOX) via flow cytometry. SBP was increased by ACTH (P < 0.0005) and DEX (P < 0.0005). Alpha-lipoic acid alone did not alter SBP. With alpha-lipoic acid pretreatment, SBP was increased by ACTH (P' < 0.005) but not by DEX. Alpha-lipoic partially prevented ACTH-HT (P' < 0.0005) and fully prevented DEX-HT (P' < 0.0005) but failed to reverse DEX-HT. ACTH and DEX did not increase MitoSOX signal. In ACTH-hypertensive rats, high-dose alpha-lipoic acid (100 mg/rat/day) did not decrease SBP further but raised MitoSOX signal (P < 0.001), suggesting prooxidant activity. Glucocorticoid-induced hypertension in rats is prevented by alpha-lipoic acid via mechanisms other than mitochondrial superoxide reduction.

Incidence, aetiology and prevention of musculoskeletal injuries in volleyball: A systematic review of the literature.

PubMed

Kilic, O; Maas, M; Verhagen, E; Zwerver, J; Gouttebarge, V

2017-07-01

Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies.

A national program for injury prevention in children and adolescents: the injury free coalition for kids.

PubMed

Pressley, Joyce C; Barlow, Barbara; Durkin, Maureen; Jacko, Sally A; Dominguez, DiLenny Roca; Johnson, Lenita

2005-09-01

Injury is the leading cause of death and a major source of preventable disability in children. Mechanisms of injury are rooted in a complex web of social, economic, environmental, criminal, and behavioral factors that necessitate a multifaceted, systematic injury prevention approach. This article describes the injury burden and the way physicians, community coalitions, and a private foundation teamed to impact the problem first in an urban minority community and then through a national program. Through our injury prevention work in a resource-limited neighborhood, a national model evolved that provides a systematic framework through which education and other interventions are implemented. Interventions are aimed at changing the community and home environments physically (safe play areas and elimination of community and home hazards) and socially (education and supervised extracurricular activities with mentors). This program, based on physician-community partnerships and private foundation financial support, expanded to 40 sites in 37 cities, representing all 10 US trauma regions. Each site is a local adaptation of the Injury Free Coalition model also referred to as the ABC's of injury prevention: A, "analyze injury data through local injury surveillance"; B, "build a local coalition"; C, "communicate the problem and raise awareness that injuries are a preventable public health problem"; D, "develop interventions and injury prevention activities to create safer environments and activities for children"; and E, "evaluate the interventions with ongoing surveillance." It is feasible to develop a comprehensive injury prevention program of national scope using a voluntary coalition of trauma centers, private foundation financial and technical support, and a local injury prevention model with a well-established record of reducing and sustaining lower injury rates for inner-city children and adolescents.