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Sample records for persistent mitochondrial damage

  1. Persistent damage induces mitochondrial DNA degradation

    PubMed Central

    Shokolenko, Inna N.; Wilson, Glenn L.; Alexeyev, Mikhail F.

    2013-01-01

    Considerable progress has been made recently toward understanding the processes of mitochondrial DNA (mtDNA) damage and repair. However, a paucity of information still exists regarding the physiological effects of persistent mtDNA damage. This is due, in part, to experimental difficulties associated with targeting mtDNA for damage, while sparing nuclear DNA. Here, we characterize two systems designed for targeted mtDNA damage based on the inducible (Tet-ON) mitochondrial expression of the bacterial enzyme, exonuclease III, and the human enzyme, uracil-N-glyosylase containing the Y147A mutation. In both systems, damage was accompanied by degradation of mtDNA, which was detectable by six hours after induction of mutant uracil-N-glycosylase and by twelve hours after induction of exoIII. Unexpectedly, increases in the steady-state levels of single-strand lesions, which led to degradation, were small in absolute terms indicating that both abasic sites and single-strand gaps may be poorly tolerated in mtDNA. mtDNA degradation was accompanied by the loss of expression of mtDNA-encoded COX2. After withdrawal of the inducer, recovery from mtDNA depletion occurred faster in the system expressing exonuclease III, but in both systems reduced mtDNA levels persisted longer than 144h after doxycycline withdrawal. mtDNA degradation was followed by reduction and loss of respiration, decreased membrane potential, reduced cell viability, reduced intrinsic reactive oxygen species production, slowed proliferation, and changes in mitochondrial morphology (fragmentation of the mitochondrial network, rounding and “foaming” of the mitochondria). The mutagenic effects of abasic sites in mtDNA were low, which indicates that damaged mtDNA molecules may be degraded if not rapidly repaired. This study establishes, for the first time, that mtDNA degradation can be a direct and immediate consequence of persistent mtDNA damage and that increased ROS production is not an invariant consequence

  2. Mitochondrial DNA Damage and Diseases

    PubMed Central

    Singh, Gyanesh; Pachouri, U C; Khaidem, Devika Chanu; Kundu, Aman; Chopra, Chirag; Singh, Pushplata

    2015-01-01

    Various endogenous and environmental factors can cause mitochondrial DNA (mtDNA) damage.  One of the reasons for enhanced mtDNA damage could be its proximity to the source of oxidants, and lack of histone-like protective proteins. Moreover, mitochondria contain inadequate DNA repair pathways, and, diminished DNA repair capacity may be one of the factors responsible for high mutation frequency of the mtDNA. mtDNA damage might cause impaired mitochondrial function, and, unrepaired mtDNA damage has been frequently linked with several diseases. Exploration of mitochondrial perspective of diseases might lead to a better understanding of several diseases, and will certainly open new avenues for detection, cure, and prevention of ailments.

  3. Mitochondrial DNA damage induced autophagy, cell death, and disease

    PubMed Central

    Van Houten, Bennett; Hunter, Senyene E.; Meyer, Joel N.

    2016-01-01

    Mammalian mitochondria contain multiple small genomes. While these organelles have efficient base excision removal of oxidative DNA lesions and alkylation damage, many DNA repair systems that work on nuclear DNA damage are not active in mitochondria. What is the fate of DNA damage in the mitochondria that cannot be repaired or that overwhelms the repair system? Some forms of mitochondrial DNA damage can apparently trigger mitochondrial DNA destruction, either via direct degradation or through specific forms of autophagy, such as mitophagy. However, accumulation of certain types of mitochondrial damage, in the absence of DNA ligase III (Lig3) or exonuclease G (EXOG), enzymes required for repair, can directly trigger cell death. This review examines the cellular effects of persistent damage to mitochondrial genomes and discusses the very different cell fates that occur in response to different kinds of damage. PMID:26709760

  4. Oxidative stress, mitochondrial damage and neurodegenerative diseases

    PubMed Central

    Guo, Chunyan; Sun, Li; Chen, Xueping; Zhang, Danshen

    2013-01-01

    Oxidative stress and mitochondrial damage have been implicated in the pathogenesis of several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Oxidative stress is characterized by the overproduction of reactive oxygen species, which can induce mitochondrial DNA mutations, damage the mitochondrial respiratory chain, alter membrane permeability, and influence Ca2+ homeostasis and mitochondrial defense systems. All these changes are implicated in the development of these neurodegenerative diseases, mediating or amplifying neuronal dysfunction and triggering neurodegeneration. This paper summarizes the contribution of oxidative stress and mitochondrial damage to the onset of neurodegenerative eases and discusses strategies to modify mitochondrial dysfunction that may be attractive therapeutic interventions for the treatment of various neurodegenerative diseases. PMID:25206509

  5. Oxidative damage and mitochondrial decay in aging.

    PubMed Central

    Shigenaga, M K; Hagen, T M; Ames, B N

    1994-01-01

    We argue for the critical role of oxidative damage in causing the mitochondrial dysfunction of aging. Oxidants generated by mitochondria appear to be the major source of the oxidative lesions that accumulate with age. Several mitochondrial functions decline with age. The contributing factors include the intrinsic rate of proton leakage across the inner mitochondrial membrane (a correlate of oxidant formation), decreased membrane fluidity, and decreased levels and function of cardiolipin, which supports the function of many of the proteins of the inner mitochondrial membrane. Acetyl-L-carnitine, a high-energy mitochondrial substrate, appears to reverse many age-associated deficits in cellular function, in part by increasing cellular ATP production. Such evidence supports the suggestion that age-associated accumulation of mitochondrial deficits due to oxidative damage is likely to be a major contributor to cellular, tissue, and organismal aging. PMID:7971961

  6. Mitochondrial DNA Damage and its Consequences for Mitochondrial Gene Expression

    PubMed Central

    Cline, Susan D.

    2012-01-01

    How mitochondria process DNA damage and whether a change in the steady-state level of mitochondrial DNA damage (mtDNA) contributes to mitochondrial dysfunction are questions that fuel burgeoning areas of research into aging and disease pathogenesis. Over the past decade, researchers have identified and measured various forms of endogenous and environmental mtDNA damage and have elucidated mtDNA repair pathways. Interestingly, mitochondria do not appear to contain the full range of DNA repair mechanisms that operate in the nucleus, although mtDNA contains types of damage that are targets of each nuclear DNA repair pathway. The reduced repair capacity may, in part, explain the high mutation frequency of the mitochondrial chromosome. Since mtDNA replication is dependent on transcription, mtDNA damage may alter mitochondrial gene expression at three levels: by causing DNA polymerase γ nucleotide incorporation errors leading to mutations, by interfering with the priming of mtDNA replication by the mitochondrial RNA polymerase, or by inducing transcriptional mutagenesis or premature transcript termination. This review summarizes our current knowledge of mtDNA damage, its repair, and its effects on mtDNA integrity and gene expression. PMID:22728831

  7. Persistent impairment of mitochondrial and tissue redox status during lithium-pilocarpine-induced epileptogenesis

    PubMed Central

    Waldbaum, Simon; Liang, Li-Ping; Patel, Manisha

    2016-01-01

    Mitochondrial dysfunction and oxidative stress are known to occur following acute seizure activity but their contribution during epileptogenesis is largely unknown. The goal of this study was to determine the extent of mitochondrial oxidative stress, changes to redox status, and mitochondrial DNA (mtDNA) damage during epileptogenesis in the lithium-pilocarpine model of temporal lobe epilepsy. Mitochondrial oxidative stress, changes in tissue and mitochondrial redox status, and mtDNA damage were assessed in the hippocampus and neocortex of Sprague–Dawley rats at time points (24 h to 3 months) following lithium-pilocarpine administration. A time-dependent increase in mitochondrial hydrogen peroxide (H2O2) production coincident with increased mtDNA lesion frequency in the hippocampus was observed during epileptogenesis. Acute increases (24–48 h) in H2O2 production and mtDNA lesion frequency were dependent on the severity of convulsive seizure activity during initial status epilepticus. Tissue levels of GSH, GSH/GSSG, coenzyme A (CoASH), and CoASH/CoASSG were persistently impaired at all measured time points throughout epileptogenesis, that is, acutely (24–48 h), during the ‘latent period’ (48 h to 7 days), and chronic epilepsy (21 days to 3 months). Together with our previous work, these results demonstrate the model independence of mitochondrial oxidative stress, genomic instability, and persistent impairment of mitochondrial specific redox status during epileptogenesis. Lasting impairment of mitochondrial and tissue redox status during the latent period, in addition to the acute and chronic phases of epileptogenesis, suggests that redox-dependent processes may contribute to the progression of epileptogenesis in experimental temporal lobe epilepsy. PMID:21219330

  8. Mitochondrial DNA replacement versus nuclear DNA persistence

    NASA Astrophysics Data System (ADS)

    Serva, Maurizio

    2006-10-01

    In this paper we consider two populations whose generations are not overlapping and whose size is large. The number of males and females in both populations is constant. Any generation is replaced by a new one and any individual has two parents concerning nuclear DNA and a single one (the mother) concerning mtDNA. Moreover, at any generation some individuals migrate from the first population to the second. In a finite random time T, the mtDNA of the second population is completely replaced by the mtDNA of the first. In the same time, the nuclear DNA is not completely replaced and a fraction F of the ancient nuclear DNA persists. We compute both T and F. Since this study shows that complete replacement of mtDNA in a population is compatible with the persistence of a large fraction of nuclear DNA, it may have some relevance for the 'out of Africa'/multiregional debate in palaeoanthropology.

  9. Cancer cells recovering from damage exhibit mitochondrial restructuring and increased aerobic glycolysis

    SciTech Connect

    Akakura, Shin; Ostrakhovitch, Elena; Sanokawa-Akakura, Reiko; Tabibzadeh, Siamak

    2014-06-13

    Highlights: • Some cancer cells recover from severe damage that causes cell death in majority of cells. • Damage-Recovered (DR) cancer cells show reduced mitochondria, mDNA and mitochondrial enzymes. • DR cells show increased aerobic glycolysis, ATP, cell proliferation, and resistance to damage. • DR cells recovered from in vivo damage also show increased glycolysis and proliferation rate. - Abstract: Instead of relying on mitochondrial oxidative phosphorylation, most cancer cells rely heavily on aerobic glycolysis, a phenomenon termed as “the Warburg effect”. We considered that this effect is a direct consequence of damage which persists in cancer cells that recover from damage. To this end, we studied glycolysis and rate of cell proliferation in cancer cells that recovered from severe damage. We show that in vitro Damage-Recovered (DR) cells exhibit mitochondrial structural remodeling, display Warburg effect, and show increased in vitro and in vivo proliferation and tolerance to damage. To test whether cancer cells derived from tumor microenvironment can show similar properties, we isolated Damage-Recovered (T{sup DR}) cells from tumors. We demonstrate that T{sup DR} cells also show increased aerobic glycolysis and a high proliferation rate. These findings show that Warburg effect and its consequences are induced in cancer cells that survive severe damage.

  10. PCR-Based Analysis of Mitochondrial DNA Copy Number, Mitochondrial DNA Damage, and Nuclear DNA Damage.

    PubMed

    Gonzalez-Hunt, Claudia P; Rooney, John P; Ryde, Ian T; Anbalagan, Charumathi; Joglekar, Rashmi; Meyer, Joel N

    2016-01-01

    Because of the role that DNA damage and depletion play in human disease, it is important to develop and improve tools to assess these endpoints. This unit describes PCR-based methods to measure nuclear and mitochondrial DNA damage and copy number. Long amplicon quantitative polymerase chain reaction (LA-QPCR) is used to detect DNA damage by measuring the number of polymerase-inhibiting lesions present based on the amount of PCR amplification; real-time PCR (RT-PCR) is used to calculate genome content. In this unit, we provide step-by-step instructions to perform these assays in Homo sapiens, Mus musculus, Rattus norvegicus, Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, Oryzias latipes, Fundulus grandis, and Fundulus heteroclitus, and discuss the advantages and disadvantages of these assays. PMID:26828332

  11. PCR-based analysis of mitochondrial DNA copy number, mitochondrial DNA damage, and nuclear DNA damage

    PubMed Central

    Gonzalez-Hunt, Claudia P.; Rooney, John P.; Ryde, Ian T.; Anbalagan, Charumathi; Joglekar, Rashmi

    2016-01-01

    Because of the role DNA damage and depletion play in human disease, it is important to develop and improve tools to assess these endpoints. This unit describes PCR-based methods to measure nuclear and mitochondrial DNA damage and copy number. Long amplicon quantitative polymerase chain reaction (LA-QPCR) is used to detect DNA damage by measuring the number of polymerase-inhibiting lesions present based on the amount of PCR amplification; real-time PCR (RT-PCR) is used to calculate genome content. In this unit we provide step-by-step instructions to perform these assays in Homo sapiens, Mus musculus, Rattus norvegicus, Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, Oryzias latipes, Fundulus grandis, and Fundulus heteroclitus, and discuss the advantages and disadvantages of these assays. PMID:26828332

  12. FUS Interacts with HSP60 to Promote Mitochondrial Damage

    PubMed Central

    Deng, Jianwen; Yang, Mengxue; Chen, Yanbo; Chen, Xiaoping; Liu, Jianghong; Sun, Shufeng; Cheng, Haipeng; Li, Yang; Bigio, Eileen H.; Mesulam, Marsel; Xu, Qi; Du, Sidan; Fushimi, Kazuo; Zhu, Li; Wu, Jane Y.

    2015-01-01

    FUS-proteinopathies, a group of heterogeneous disorders including ALS-FUS and FTLD-FUS, are characterized by the formation of inclusion bodies containing the nuclear protein FUS in the affected patients. However, the underlying molecular and cellular defects remain unclear. Here we provide evidence for mitochondrial localization of FUS and its induction of mitochondrial damage. Remarkably, FTLD-FUS brain samples show increased FUS expression and mitochondrial defects. Biochemical and genetic data demonstrate that FUS interacts with a mitochondrial chaperonin, HSP60, and that FUS translocation to mitochondria is, at least in part, mediated by HSP60. Down-regulating HSP60 reduces mitochondrially localized FUS and partially rescues mitochondrial defects and neurodegenerative phenotypes caused by FUS expression in transgenic flies. This is the first report of direct mitochondrial targeting by a nuclear protein associated with neurodegeneration, suggesting that mitochondrial impairment may represent a critical event in different forms of FUS-proteinopathies and a common pathological feature for both ALS-FUS and FTLD-FUS. Our study offers a potential explanation for the highly heterogeneous nature and complex genetic presentation of different forms of FUS-proteinopathies. Our data also suggest that mitochondrial damage may be a target in future development of diagnostic and therapeutic tools for FUS-proteinopathies, a group of devastating neurodegenerative diseases. PMID:26335776

  13. Mitochondrial DNA damage and efficiency of ATP biosynthesis: mathematical model.

    PubMed

    Beregovskaya, N; Maiboroda, R

    1995-01-21

    The role of mitochondrial DNA (mtDNA) damage in ageing processes and in malignant transformation of a cell is discussed. A mathematical model of the mtDNA population in a cell and in tissue is constructed. The model describes the effects of mtDNA damages accumulated during ageing and some features of malignant transformation and regeneration. PMID:7891454

  14. Oxidative DNA damage stalls the human mitochondrial replisome

    PubMed Central

    Stojkovič, Gorazd; Makarova, Alena V.; Wanrooij, Paulina H.; Forslund, Josefin; Burgers, Peter M.; Wanrooij, Sjoerd

    2016-01-01

    Oxidative stress is capable of causing damage to various cellular constituents, including DNA. There is however limited knowledge on how oxidative stress influences mitochondrial DNA and its replication. Here, we have used purified mtDNA replication proteins, i.e. DNA polymerase γ holoenzyme, the mitochondrial single-stranded DNA binding protein mtSSB, the replicative helicase Twinkle and the proposed mitochondrial translesion synthesis polymerase PrimPol to study lesion bypass synthesis on oxidative damage-containing DNA templates. Our studies were carried out at dNTP levels representative of those prevailing either in cycling or in non-dividing cells. At dNTP concentrations that mimic those in cycling cells, the replication machinery showed substantial stalling at sites of damage, and these problems were further exacerbated at the lower dNTP concentrations present in resting cells. PrimPol, the translesion synthesis polymerase identified inside mammalian mitochondria, did not promote mtDNA replication fork bypass of the damage. This argues against a conventional role for PrimPol as a mitochondrial translesion synthesis DNA polymerase for oxidative DNA damage; however, we show that Twinkle, the mtDNA replicative helicase, is able to stimulate PrimPol DNA synthesis in vitro, suggestive of an as yet unidentified role of PrimPol in mtDNA metabolism. PMID:27364318

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

    SciTech Connect

    Chen, Qun; Yin, Guotian; Stewart, Sarah; Hu, Ying; Lesnefsky, Edward J.

    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 to 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.

  16. Nanoparticle-Mediated Mitochondrial Damage Induces Apoptosis in Cancer.

    PubMed

    Mallick, Abhik; More, Piyush; Syed, Muhammed Muazzam Kamil; Basu, Sudipta

    2016-06-01

    Detouring of conventional DNA damaging anticancer drugs into mitochondria to damage mitochondrial DNA is evolving as a promising strategy in chemotherapy. Inhibiting single target in mitochondria would eventually lead to the emergence of drug resistance. Moreover, targeting mitochondria selectively in cancer cells, keeping them intact in healthy cells, remains a major challenge. Herein, triphenylphosphine (TPP)-coated positively charged 131.6 nm spherical nanoparticles (NPs) comprised of α-tocopheryl succinate (TOS, inhibitor of complex II in electron transport chain) and obatoclax (Obt, inhibitor of Bcl-2) were engineered. The TOS-TPP-Obt-NPs entered into acidic lysosomes via macropinocytosis, followed by lysosomal escape and finally homed into mitochondria over a period of 24 h. Subsequently, these TOS-TPP-Obt-NPs triggered mitochondrial outer membrane permeabilization (MOMP) by inhibiting antiapoptotic Bcl-2, leading to Cytochrome C release. These TOS-TPP-Obt-NPs mediated mitochondrial damage induced cellular apoptosis through caspase-9 and caspase-3 cleavage to show improved efficacy in HeLa cells. Moreover, TOS-TPP-Obt-NPs induced MOMP in drug-resistant triple negative breast cancer cells (MDA-MB-231), leading to remarkable efficacy, compared to the combination of free drugs in higher drug concentrations. Results presented here clearly stimulate the usage of multiple drugs to perturb simultaneously diverse targets, selectively in mitochondria, as next-generation cancer therapeutics. PMID:27160664

  17. Mechanisms of Mitochondrial Damage in Keratinocytes by Pemphigus Vulgaris Antibodies*

    PubMed Central

    Kalantari-Dehaghi, Mina; Chen, Yumay; Deng, Wu; Chernyavsky, Alex; Marchenko, Steve; Wang, Ping H.; Grando, Sergei A.

    2013-01-01

    The development of nonhormonal treatment of pemphigus vulgaris (PV) has been hampered by a lack of clear understanding of the mechanisms leading to keratinocyte (KC) detachment and death in pemphigus. In this study, we sought to identify changes in the vital mitochondrial functions in KCs treated with the sera from PV patients and healthy donors. PV sera significantly increased proton leakage from KCs, suggesting that PV IgGs increase production of reactive oxygen species. Indeed, measurement of intracellular reactive oxygen species production showed a drastic increase of cell staining in response to treatment by PV sera, which was confirmed by FACS analysis. Exposure of KCs to PV sera also caused dramatic changes in the mitochondrial membrane potential detected with the JC-1 dye. These changes can trigger the mitochondria-mediated intrinsic apoptosis. Although sera from different PV patients elicited unique patterns of mitochondrial damage, the mitochondria-protecting drugs nicotinamide (also called niacinamide), minocycline, and cyclosporine A exhibited a uniform protective effect. Their therapeutic activity was validated in the passive transfer model of PV in neonatal BALB/c mice. The highest efficacy of mitochondrial protection of the combination of these drugs found in mitochondrial assay was consistent with the ability of the same drug combination to abolish acantholysis in mouse skin. These findings provide a theoretical background for clinical reports of the efficacy of mitochondria-protecting drugs in PV patients. Pharmacological protection of mitochondria and/or compensation of an altered mitochondrial function may therefore become a novel approach to development of personalized nonhormonal therapies of patients with this potentially lethal autoimmune blistering disease. PMID:23599429

  18. MTERF2 contributes to MPP(+)-induced mitochondrial dysfunction and cell damage.

    PubMed

    Han, Yanyan; Gao, Peiye; Qiu, Shi; Zhang, Linbing; Yang, Ling; Zuo, Ji; Zhong, Chunjiu; Zhu, Shun; Liu, Wen

    2016-02-26

    Parkinson's disease (PD) is a common neurodegenerative disorder whose pathogenesis is under intense investigation. Substantial evidence indicates that mitochondrial dysfunction plays a central role in the pathophysiology of PD. Several mitochondrial internal regulating factors act to maintain the mitochondrial function. However, how these internal regulating factors contribute to mitochondrial dysfunction in PD remains elusive. One of these factors, mitochondrial transcription termination factor 2 (MTERF2), has been implicated in the regulation of oxidative phosphorylation by modulating mitochondrial DNA transcription. Here, we discovered a new role of MTERF2 in regulating mitochondrial dysfunction and cell damage induced by MPP(+) in SH-SY5Y cells. We found that MPP(+) treatment elevated MTERF2 expression, induced mitochondrial dysfunction and cell damage, which was alleviated by MTERF2 knockdown. These findings demonstrate that MTERF2 contributes to MPP(+)-induced mitochondrial disruption and cell damage. This study indicates that MTERF2 is a potential therapeutic target for environmentally induced Parkinson's disease. PMID:26826381

  19. Deficiency in the inner mitochondrial membrane peptidase 2-like (Immp21) gene increases ischemic brain damage and impairs mitochondrial function

    PubMed Central

    Ma, Yi; Mehta, Suresh L.; Lu, Baisong; Andy Li, P.

    2011-01-01

    Mitochondrial dysfunction plays an important role in mediating ischemic brain damage. Immp2l is an inner mitochondrial membrane peptidase that processes mitochondrial proteins cytochrome c1 (Cyc1). Homozygous mutation of Immp2l (Immp2lTg(Tyr)979Ove or Immp2l−/−) elevates mitochondrial membrane potential, increases superoxide (•O2−) production in the brain and impairs fertility. The objectives of this study are to explore the effects of heterozygous mutation of lmmp2l (Immp2l+/−) on ischemic outcome and to determine the influence of Immp2l deficiency on brain mitochondria after stroke. Male Immp2l+/− and wild-type (WT) mice were subjected to 1-h focal cerebral ischemia. Their brains were harvested after 5 and 24-h of reperfusion. The results showed that infarct volume and DNA oxidative damage significantly increased in the Immp2l+/− mice. There were no obvious cerebral vasculature abnormalities between the two types of mice viewed by Indian ink perfusion. The increased damage in Immp2l+/− mice was associated with early increase in •O2− production. Mitochondrial respiratory rate, total mitochondrial respiratory capacity and mitochondrial respiratory complex activities were decreased at 5-h of recirculation in Immp2l+/− mice compared to WT mice. Our results suggest that lmmp2l deficiency increases ischemic brain damage by enhancing •O2− production and damaging mitochondrial functional performance. PMID:21824519

  20. Mitochondrial Permeability Transition: New Findings and Persisting Uncertainties.

    PubMed

    Izzo, Valentina; Bravo-San Pedro, José Manuel; Sica, Valentina; Kroemer, Guido; Galluzzi, Lorenzo

    2016-09-01

    Several insults cause the inner mitochondrial membrane to abruptly lose osmotic homeostasis, hence initiating a regulated variant of cell death known as 'mitochondrial permeability transition' (MPT)-driven necrosis. MPT provides an etiological contribution to several human disorders characterized by the acute loss of post-mitotic cells, including cardiac and cerebral ischemia. Nevertheless, the precise molecular determinants of MPT remain elusive, which considerably hampers the development of clinically implementable cardio- or neuroprotective strategies targeting this process. We summarize recent findings shedding new light on the supramolecular entity that mediates MPT, the so-called 'permeability transition pore complex' (PTPC). Moreover, we discuss hitherto unresolved controversies on MPT and analyze the major obstacles that still preclude the complete understanding and therapeutic targeting of this process. PMID:27161573

  1. Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage.

    PubMed

    Guarini, Giacinta; Kiyooka, Takahiko; Ohanyan, Vahagn; Pung, Yuh Fen; Marzilli, Mario; Chen, Yeong Renn; Chen, Chwen Lih; Kang, Patrick T; Hardwick, James P; Kolz, Christopher L; Yin, Liya; Wilson, Glenn L; Shokolenko, Inna; Dobson, James G; Fenton, Richard; Chilian, William M

    2016-05-01

    Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process. PMID:27040114

  2. Spaceflight environment induces mitochondrial oxidative damage in ocular tissue.

    PubMed

    Mao, Xiao W; Pecaut, Michael J; Stodieck, Louis S; Ferguson, Virginia L; Bateman, Ted A; Bouxsein, Mary; Jones, Tamako A; Moldovan, Maria; Cunningham, Christopher E; Chieu, Jenny; Gridley, Daila S

    2013-10-01

    A recent report shows that more than 30% of the astronauts returning from Space Shuttle missions or the International Space Station (ISS) were diagnosed with eye problems that can cause reduced visual acuity. We investigate here whether spaceflight environment-associated retinal damage might be related to oxidative stress-induced mitochondrial apoptosis. Female C57BL/6 mice were flown in the space shuttle Atlantis (STS-135), and within 3-5 h of landing, the spaceflight and ground-control mice, similarly housed in animal enclosure modules (AEMs) were euthanized and their eyes were removed for analysis. Changes in expression of genes involved in oxidative stress, mitochondrial and endothelial cell biology were examined. Apoptosis in the retina was analyzed by caspase-3 immunocytochemical analysis and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Levels of 4-hydroxynonenal (4-HNE) protein, an oxidative specific marker for lipid peroxidation were also measured. Evaluation of spaceflight mice and AEM ground-control mice showed that expression of several genes playing central roles in regulating the mitochondria-associated apoptotic pathway were significantly altered in mouse ocular tissue after spaceflight compared to AEM ground-control mice. In addition, the mRNA levels of several genes, which are responsible for regulating the production of reactive oxygen species were also significantly up-regulated in spaceflight samples compared to AEM ground-control mice. Further more, the level of HNE protein was significantly elevated in the retina after spaceflight compared to controls. Our results also revealed that spaceflight conditions induced significant apoptosis in the retina especially inner nuclear layer (INL) and ganglion cell layer (GCL) compared to AEM ground controls. The data provided the first evidence that spaceflight conditions induce oxidative damage that results in mitochondrial apoptosis in the retina. This data suggest

  3. Methoxychlor causes mitochondrial dysfunction and oxidative damage in the mouse ovary

    SciTech Connect

    Gupta, R.K.; Schuh, R.A.; Fiskum, G.; Flaws, J.A. . E-mail: jflaws@epi.umaryland.edu

    2006-11-01

    Methoxychlor (MXC) is an organochlorine pesticide that reduces fertility in female rodents by causing ovarian atrophy, persistent estrous cyclicity, and antral follicle atresia (apoptotic cell death). Oxidative damage resulting from reactive oxygen species (ROS) generation has been demonstrated to lead to toxicant-induced cell death. Thus, this work tested the hypothesis that MXC causes oxidative damage to the mouse ovary and affects mitochondrial respiration in a manner that stimulates ROS production. For the in vitro experiments, mitochondria were collected from adult cycling mouse ovaries, treated with vehicle (dimethyl sulfoxide; DMSO) or MXC, and subjected to polarographic measurements of respiration. For the in vivo experiments, adult cycling CD-1 mice were dosed with either vehicle (sesame oil) or MXC for 20 days. After treatment, ovarian mitochondria were isolated and subjected to measurements of respiration and fluorimetric measurements of H{sub 2}O{sub 2} production. Some ovaries were also fixed and processed for immunohistochemistry using antibodies for ROS production markers: nitrotyrosine and 8-hydroxy-2'-deoxyguanosine (8-OHG). Ovaries from in vivo experiments were also used to measure the mRNA expression and activity of antioxidants such as Cu/Zn superoxide dismutase (SOD1), glutathione peroxidase (GPX), and catalase (CAT). The results indicate that MXC significantly impairs mitochondrial respiration, increases production of H{sub 2}O{sub 2}, causes more staining for nitrotyrosine and 8-OHG in antral follicles, and decreases the expression and activity of SOD1, GPX, and CAT as compared to controls. Collectively, these data indicate that MXC inhibits mitochondrial respiration, causes ROS production, and decreases antioxidant expression and activity in the ovary, specifically in the antral follicles. Therefore, it is possible that MXC causes atresia of ovarian antral follicles by inducing oxidative stress through mitochondrial production of ROS.

  4. Lamivudine/telbivudine-associated neuromyopathy: neurogenic damage, mitochondrial dysfunction and mitochondrial DNA depletion

    PubMed Central

    Xu, Hongliang; Wang, Zhaoxia; Zheng, Lemin; Zhang, Wei; Lv, He; Jin, Suqin; Yuan, Yun

    2014-01-01

    Aims Myopathy or neuropathy has been associated with lamivudine/telbivudine therapy in hepatitis B patients. We aim to describe the pathological changes of lamivudine/telbivudine-associated neuromyopathy. Methods We retrospectively recruited six patients who were diagnosed with nucleotide analogues-associated myopathy or neuropathy. Muscle and nerve biopsy were performed, and the specimens were prepared for the light microscopy and electron microscopy. Genomic DNA was extracted from frozen muscle specimens, and the mitochondrial DNA (mtDNA) content was quantified by real-time PCR. Results Recovery of the myopathy can be achieved after the discontinuation or changing the drugs to entecavir. Muscle and nerve biopsy revealed similar changes under either the light or electronic microscopy in all the subjects. Quantitative real-time PCR revealed decrease of mtDNA content in the affected muscle. Conclusions MtDNA depletion results in mitochondrial dysfunction in the lamivudine/telbivudine-associated neuromyopathy. Myopathy was characterised by mitochondrial dysfunction accompanied with neurogenic damage due to axonal neuropathy. Ultrastructure changes of mitochondria included vacuolisation, simplification of the cristae and homogenised matrix. PMID:25190818

  5. Reduced calcium-dependent mitochondrial damage underlies the reduced vulnerability of excitotoxicity-tolerant hippocampal neurons.

    PubMed

    Pivovarova, Natalia B; Stanika, Ruslan I; Watts, Charlotte A; Brantner, Christine A; Smith, Carolyn L; Andrews, S Brian

    2008-03-01

    In central neurons, over-stimulation of NMDA receptors leads to excessive mitochondrial calcium accumulation and damage, which is a critical step in excitotoxic death. This raises the possibility that low susceptibility to calcium overload-induced mitochondrial damage might characterize excitotoxicity-resistant neurons. In this study, we have exploited two complementary models of preconditioning-induced excitotoxicity resistance to demonstrate reduced calcium-dependent mitochondrial damage in NMDA-tolerant hippocampal neurons. We have further identified adaptations in mitochondrial calcium handling that account for enhanced mitochondrial integrity. In both models, enhanced tolerance was associated with improved preservation of mitochondrial membrane potential and structure. In the first model, which exhibited modest neuroprotection, mitochondria-dependent calcium deregulation was delayed, even though cytosolic and mitochondrial calcium loads were quantitatively unchanged, indicating that enhanced mitochondrial calcium capacity accounts for reduced injury. In contrast, the second model, which exhibited strong neuroprotection, displayed further delayed calcium deregulation and reduced mitochondrial damage because downregulation of NMDA receptor surface expression depressed calcium loading. Reducing calcium entry also modified the chemical composition of the calcium-buffering precipitates that form in calcium-loaded mitochondria. It thus appears that reduced mitochondrial calcium loading is a major factor underlying the robust neuroprotection seen in highly tolerant cells. PMID:18036152

  6. Dicarbonyls linked to damage in the powerhouse: glycation of mitochondrial proteins and oxidative stress

    PubMed Central

    Rabbani, Naila; Thornalley, Paul J.

    2009-01-01

    Protection of mitochondrial proteins from glycation by endogenous dicarbonyl compounds, methylglyoxal and glyoxal, was found recently to prevent increased formation of reactive oxygen species and oxidative and nitrosative damage to the proteome during aging and produce life extension in the nematode Caenorhabditis elegans. This suggests that dicarbonyl glycation damage to the mitochondrial proteome may be a preceding event to mitochondrial dysfunction leading to oxidative stress. Future research will address the functional charges in mitochondrial proteins that are the targets for dicarbonyl glycation. PMID:18793186

  7. Mitochondrial Oxidative Stress, Mitochondrial DNA Damage and Their Role in Age-Related Vascular Dysfunction

    PubMed Central

    Mikhed, Yuliya; Daiber, Andreas; Steven, Sebastian

    2015-01-01

    The prevalence of cardiovascular diseases is significantly increased in the older population. Risk factors and predictors of future cardiovascular events such as hypertension, atherosclerosis, or diabetes are observed with higher frequency in elderly individuals. A major determinant of vascular aging is endothelial dysfunction, characterized by impaired endothelium-dependent signaling processes. Increased production of reactive oxygen species (ROS) leads to oxidative stress, loss of nitric oxide (•NO) signaling, loss of endothelial barrier function and infiltration of leukocytes to the vascular wall, explaining the low-grade inflammation characteristic for the aged vasculature. We here discuss the importance of different sources of ROS for vascular aging and their contribution to the increased cardiovascular risk in the elderly population with special emphasis on mitochondrial ROS formation and oxidative damage of mitochondrial DNA. Also the interaction (crosstalk) of mitochondria with nicotinamide adenosine dinucleotide phosphate (NADPH) oxidases is highlighted. Current concepts of vascular aging, consequences for the development of cardiovascular events and the particular role of ROS are evaluated on the basis of cell culture experiments, animal studies and clinical trials. Present data point to a more important role of oxidative stress for the maximal healthspan (healthy aging) than for the maximal lifespan. PMID:26184181

  8. Protection from palmitate-induced mitochondrial DNA damage prevents from mitochondrial oxidative stress, mitochondrial dysfunction, apoptosis, and impaired insulin signaling in rat L6 skeletal muscle cells.

    PubMed

    Yuzefovych, Larysa V; Solodushko, Viktoriya A; Wilson, Glenn L; Rachek, Lyudmila I

    2012-01-01

    Saturated free fatty acids have been implicated in the increase of oxidative stress, mitochondrial dysfunction, apoptosis, and insulin resistance seen in type 2 diabetes. The purpose of this study was to determine whether palmitate-induced mitochondrial DNA (mtDNA) damage contributed to increased oxidative stress, mitochondrial dysfunction, apoptosis, impaired insulin signaling, and reduced glucose uptake in skeletal muscle cells. Adenoviral vectors were used to deliver the DNA repair enzyme human 8-oxoguanine DNA glycosylase/(apurinic/apyrimidinic) lyase (hOGG1) to mitochondria in L6 myotubes. After palmitate exposure, we evaluated mtDNA damage, mitochondrial function, production of mitochondrial reactive oxygen species, apoptosis, insulin signaling pathways, and glucose uptake. Protection of mtDNA from palmitate-induced damage by overexpression of hOGG1 targeted to mitochondria significantly diminished palmitate-induced mitochondrial superoxide production, restored the decline in ATP levels, reduced activation of c-Jun N-terminal kinase (JNK) kinase, prevented cells from entering apoptosis, increased insulin-stimulated phosphorylation of serine-threonine kinase (Akt) (Ser473) and tyrosine phosphorylation of insulin receptor substrate-1, and thereby enhanced glucose transporter 4 translocation to plasma membrane, and restored insulin signaling. Addition of a specific inhibitor of JNK mimicked the effect of mitochondrial overexpression of hOGG1 and partially restored insulin sensitivity, thus confirming the involvement of mtDNA damage and subsequent increase of oxidative stress and JNK activation in insulin signaling in L6 myotubes. Our results are the first to report that mtDNA damage is the proximal cause in palmitate-induced mitochondrial dysfunction and impaired insulin signaling and provide strong evidence that targeting DNA repair enzymes into mitochondria in skeletal muscles could be a potential therapeutic treatment for insulin resistance. PMID:22128025

  9. Strenuous exercise induces mitochondrial damage in skeletal muscle of old mice

    SciTech Connect

    Lee, Sangho; Kim, Minjung; Lim, Wonchung; Kim, Taeyoung; Kang, Chounghun

    2015-05-29

    Strenuous exercise is known to cause excessive ROS generation and inflammation. However, the mechanisms responsible for the regulation of mitochondrial integrity in the senescent muscle during high-intensity exercise (HE) are not well studied. Here, we show that HE suppresses up-regulation of mitochondrial function despite increase in mitochondrial copy number, following excessive ROS production, proinflammatory cytokines and NFκB activation. Moreover, HE in the old group resulted in the decreasing of both fusion (Mfn2) and fission (Drp1) proteins that may contribute to alteration of mitochondrial morphology. This study suggests that strenuous exercise does not reverse age-related mitochondrial damage and dysfunction by the increased ROS and inflammation. - Highlights: • Effect of exercise on mitochondrial function of aged skeletal muscles was studied. • Strenuous exercise triggered excessive ROS production and inflammatory cytokines. • Strenuous exercise suppressed mitochondrial function in senescent muscle.

  10. Mitochondrial damage contributes to Pseudomonas aeruginosa activation of the inflammasome and is downregulated by autophagy.

    PubMed

    Jabir, Majid Sakhi; Hopkins, Lee; Ritchie, Neil D; Ullah, Ihsan; Bayes, Hannah K; Li, Dong; Tourlomousis, Panagiotis; Lupton, Alison; Puleston, Daniel; Simon, Anna Katharina; Bryant, Clare; Evans, Thomas J

    2015-01-01

    The nucleotide-binding domain, leucine-rich repeat containing family caspase recruitment domain containing 4 (NLRC4) inflammasome can be activated by pathogenic bacteria via products translocated through the microbial type III secretion apparatus (T3SS). Recent work has shown that activation of the NLRP3 inflammasome is downregulated by autophagy, but the influence of autophagy on NLRC4 activation is unclear. We set out to determine how autophagy might influence this process, using the bacterium Pseudomonas aeruginosa, which activates the NLRC4 inflammasome via its T3SS. Infection resulted in T3SS-dependent mitochondrial damage with increased production of reactive oxygen intermediates and release of mitochondrial DNA. Inhibiting mitochondrial reactive oxygen release or degrading intracellular mitochondrial DNA abrogated NLRC4 inflammasome activation. Moreover, macrophages lacking mitochondria failed to activate NLRC4 following infection. Removal of damaged mitochondria by autophagy significantly attenuated NLRC4 inflammasome activation. Mitochondrial DNA bound specifically to NLRC4 immunoprecipitates and transfection of mitochondrial DNA directly activated the NLRC4 inflammasome; oxidation of the DNA enhanced this effect. Manipulation of autophagy altered the degree of inflammasome activation and inflammation in an in vivo model of P. aeruginosa infection. Our results reveal a novel mechanism contributing to NLRC4 activation by P. aeruginosa via mitochondrial damage and release of mitochondrial DNA triggered by the bacterial T3SS that is downregulated by autophagy. PMID:25700738

  11. Quantitative PCR-Based Measurement of Nuclear and Mitochondrial DNA Damage and Repair in Mammalian Cells

    PubMed Central

    Furda, Amy; Santos, Janine H.; Meyer, Joel N.; Van Houten, Bennett

    2015-01-01

    In this chapter, we describe a gene-specific quantitative PCR (QPCR)-based assay for the measurement of DNA damage, using amplification of long DNA targets. This assay has been used extensively to measure the integrity of both nuclear and mitochondrial genomes exposed to different genotoxins and has proven to be particularly valuable in identifying reactive oxygen species-mediated mitochondrial DNA damage. QPCR can be used to quantify both the formation of DNA damage as well as the kinetics of damage removal. One of the main strengths of the assay is that it permits monitoring the integrity of mtDNA directly from total cellular DNA without the need for isolating mitochondria or a separate step of mitochondrial DNA purification. Here we discuss advantages and limitations of using QPCR to assay DNA damage in mammalian cells. In addition, we give a detailed protocol of the QPCR assay that helps facilitate its successful deployment in any molecular biology laboratory. PMID:24623245

  12. Persistently Altered Brain Mitochondrial Bioenergetics After Apparently Successful Resuscitation From Cardiac Arrest

    PubMed Central

    Kilbaugh, Todd J; Sutton, Robert M; Karlsson, Michael; Hansson, Magnus J; Naim, Maryam Y; Morgan, Ryan W; Bratinov, George; Lampe, Joshua W; Nadkarni, Vinay M; Becker, Lance B; Margulies, Susan S; Berg, Robert A

    2015-01-01

    Background Although advances in cardiopulmonary resuscitation have improved survival from cardiac arrest (CA), neurologic injury persists and impaired mitochondrial bioenergetics may be critical for targeted neuroresuscitation. The authors sought to determine if excellent cardiopulmonary resuscitation and postresuscitation care and good traditional survival rates result in persistently disordered cerebral mitochondrial bioenergetics in a porcine pediatric model of asphyxia-associated ventricular fibrillation CA. Methods and Results After 7 minutes of asphyxia, followed by ventricular fibrillation, 5 female 1-month-old swine (4 sham) received blood pressure–targeted care: titration of compression depth to systolic blood pressure of 90 mm Hg and vasopressor administration to a coronary perfusion pressure >20 mm Hg. All animals received protocol-based vasopressor support after return of spontaneous circulation for 4 hours before they were killed. The primary outcome was integrated mitochondrial electron transport system (ETS) function. CA animals displayed significantly decreased maximal, coupled oxidative phosphorylating respiration (OXPHOSCI+CII) in cortex (P<0.02) and hippocampus (P<0.02), as well as decreased phosphorylation and coupling efficiency (cortex, P<0.05; hippocampus, P<0.05). Complex I– and complex II–driven respiration were both significantly decreased after CA (cortex: OXPHOSCI P<0.01, ETSCII P<0.05; hippocampus: OXPHOSCI P<0.03, ETSCII P<0.01). In the hippocampus, there was a significant decrease in maximal uncoupled, nonphosphorylating respiration (ETSCI+CII), as well as a 30% reduction in citrate synthase activity (P<0.04). Conclusions Mitochondria in both the cortex and hippocampus displayed significant alterations in respiratory function after CA despite excellent cardiopulmonary resuscitation and postresuscitation care in asphyxia-associated ventricular fibrillation CA. Analysis of integrated ETS function identifies mitochondrial

  13. The Opa1-Dependent Mitochondrial Cristae Remodeling Pathway Controls Atrophic, Apoptotic, and Ischemic Tissue Damage

    PubMed Central

    Varanita, Tatiana; Soriano, Maria Eugenia; Romanello, Vanina; Zaglia, Tania; Quintana-Cabrera, Rubén; Semenzato, Martina; Menabò, Roberta; Costa, Veronica; Civiletto, Gabriele; Pesce, Paola; Viscomi, Carlo; Zeviani, Massimo; Di Lisa, Fabio; Mongillo, Marco; Sandri, Marco; Scorrano, Luca

    2015-01-01

    Summary Mitochondrial morphological and ultrastructural changes occur during apoptosis and autophagy, but whether they are relevant in vivo for tissue response to damage is unclear. Here we investigate the role of the optic atrophy 1 (OPA1)-dependent cristae remodeling pathway in vivo and provide evidence that it regulates the response of multiple tissues to apoptotic, necrotic, and atrophic stimuli. Genetic inhibition of the cristae remodeling pathway in vivo does not affect development, but protects mice from denervation-induced muscular atrophy, ischemic heart and brain damage, as well as hepatocellular apoptosis. Mechanistically, OPA1-dependent mitochondrial cristae stabilization increases mitochondrial respiratory efficiency and blunts mitochondrial dysfunction, cytochrome c release, and reactive oxygen species production. Our results indicate that the OPA1-dependent cristae remodeling pathway is a fundamental, targetable determinant of tissue damage in vivo. PMID:26039448

  14. A novel approach for organelle-specific DNA damage targeting reveals different susceptibility of mitochondrial DNA to the anticancer drugs camptothecin and topotecan

    PubMed Central

    de la Loza, M. C. Díaz; Wellinger, R. E.

    2009-01-01

    DNA is susceptible of being damaged by chemicals, UV light or gamma irradiation. Nuclear DNA damage invokes both a checkpoint and a repair response. By contrast, little is known about the cellular response to mitochondrial DNA damage. We designed an experimental system that allows organelle-specific DNA damage targeting in Saccharomyces cerevisiae. DNA damage is mediated by a toxic topoisomerase I allele which leads to the formation of persistent DNA single-strand breaks. We show that organelle-specific targeting of a toxic topoisomerase I to either the nucleus or mitochondria leads to nuclear DNA damage and cell death or to loss of mitochondrial DNA and formation of respiration-deficient ‘petite’ cells, respectively. In wild-type cells, toxic topoisomerase I–DNA intermediates are formed as a consequence of topoisomerase I interaction with camptothecin-based anticancer drugs. We reasoned that targeting of topoisomerase I to the mitochondria of top1Δ cells should lead to petite formation in the presence of camptothecin. Interestingly, camptothecin failed to generate petite; however, its derivative topotecan accumulates in mitochondria and induces petite formation. Our findings demonstrate that drug modifications can lead to organelle-specific DNA damage and thus opens new perspectives on the role of mitochondrial DNA-damage in cancer treatment. PMID:19151088

  15. Mitochondrial Dysfunction Contributes to Hypertensive Target Organ Damage: Lessons from an Animal Model of Human Disease

    PubMed Central

    Stanzione, Rosita; Volpe, Massimo

    2016-01-01

    Mechanisms underlying hypertensive target organ damage (TOD) are not completely understood. The pathophysiological role of mitochondrial oxidative stress, resulting from mitochondrial dysfunction, in development of TOD is unclear. The stroke-prone spontaneously hypertensive rat (SHRSP) is a suitable model of human hypertension and of its vascular consequences. Pathogenesis of TOD in SHRSP is multifactorial, being determined by high blood pressure levels, high salt/low potassium diet, and genetic factors. Accumulating evidence points to a key role of mitochondrial dysfunction in increased susceptibility to TOD development of SHRSP. Mitochondrial abnormalities were described in both heart and brain of SHRSP. Pharmacological compounds able to protect mitochondrial function exerted a significant protective effect on TOD development, independently of blood pressure levels. Through our research efforts, we discovered that two genes encoding mitochondrial proteins, one (Ndufc2) involved in OXPHOS complex I assembly and activity and the second one (UCP2) involved in clearance of mitochondrial ROS, are responsible, when dysregulated, for vascular damage in SHRSP. The suitability of SHRSP as a model of human disease represents a promising background for future translation of the experimental findings to human hypertension. Novel therapeutic strategies toward mitochondrial molecular targets may become a valuable tool for prevention and treatment of TOD in human hypertension. PMID:27594970

  16. Mitochondrial Dysfunction Contributes to Hypertensive Target Organ Damage: Lessons from an Animal Model of Human Disease.

    PubMed

    Rubattu, Speranza; Stanzione, Rosita; Volpe, Massimo

    2016-01-01

    Mechanisms underlying hypertensive target organ damage (TOD) are not completely understood. The pathophysiological role of mitochondrial oxidative stress, resulting from mitochondrial dysfunction, in development of TOD is unclear. The stroke-prone spontaneously hypertensive rat (SHRSP) is a suitable model of human hypertension and of its vascular consequences. Pathogenesis of TOD in SHRSP is multifactorial, being determined by high blood pressure levels, high salt/low potassium diet, and genetic factors. Accumulating evidence points to a key role of mitochondrial dysfunction in increased susceptibility to TOD development of SHRSP. Mitochondrial abnormalities were described in both heart and brain of SHRSP. Pharmacological compounds able to protect mitochondrial function exerted a significant protective effect on TOD development, independently of blood pressure levels. Through our research efforts, we discovered that two genes encoding mitochondrial proteins, one (Ndufc2) involved in OXPHOS complex I assembly and activity and the second one (UCP2) involved in clearance of mitochondrial ROS, are responsible, when dysregulated, for vascular damage in SHRSP. The suitability of SHRSP as a model of human disease represents a promising background for future translation of the experimental findings to human hypertension. Novel therapeutic strategies toward mitochondrial molecular targets may become a valuable tool for prevention and treatment of TOD in human hypertension. PMID:27594970

  17. Stationary-Phase Persisters to Ofloxacin Sustain DNA Damage and Require Repair Systems Only during Recovery

    PubMed Central

    Völzing, Katherine G.

    2015-01-01

    ABSTRACT Chronic infections are a serious health care problem, and bacterial persisters have been implicated in infection reoccurrence. Progress toward finding antipersister therapies has been slow, in part because of knowledge gaps regarding the physiology of these rare phenotypic variants. Evidence shows that growth status is important for survival, as nongrowing cultures can have 100-fold more persisters than growing populations. However, additional factors are clearly important, as persisters remain rare even in nongrowing populations. What features, beyond growth inhibition, allow persisters to survive antibiotic stress while the majority of their kin succumb to it remains an open question. To investigate this, we used stationary phase as a model nongrowing environment to study Escherichia coli persistence to ofloxacin. Given that the prevailing model of persistence attributes survival to transient dormancy and antibiotic target inactivity, we anticipated that persisters would suffer less damage than their dying kin. However, using genetic mutants, flow cytometry, fluorescence-activated cell sorting, and persistence assays, we discovered that nongrowing ofloxacin persisters experience antibiotic-induced damage that is indistinguishable from that of nonpersisters. Consistent with this, we found that these persisters required DNA repair for survival and that repair machinery was unnecessary until the posttreatment recovery period (after ofloxacin removal). These findings suggest that persistence to ofloxacin is not engendered solely by reduced antibiotic target corruption, demonstrate that what happens following antibiotic stress can be critical to the persistence phenotype, and support the notion that inhibition of DNA damage repair systems could be an effective strategy to eliminate fluoroquinolone persisters. PMID:26330511

  18. Development of a robust DNA damage model including persistent telomere-associated damage with application to secondary cancer risk assessment

    PubMed Central

    Rastgou Talemi, Soheil; Kollarovic, Gabriel; Lapytsko, Anastasiya; Schaber, Jörg

    2015-01-01

    Mathematical modelling has been instrumental to understand kinetics of radiation-induced DNA damage repair and associated secondary cancer risk. The widely accepted two-lesion kinetic (TLK) model assumes two kinds of double strand breaks, simple and complex ones, with different repair rates. Recently, persistent DNA damage associated with telomeres was reported as a new kind of DNA damage. We therefore extended existing versions of the TLK model by new categories of DNA damage and re-evaluated those models using extensive data. We subjected different versions of the TLK model to a rigorous model discrimination approach. This enabled us to robustly select a best approximating parsimonious model that can both recapitulate and predict transient and persistent DNA damage after ionizing radiation. Models and data argue for i) nonlinear dose-damage relationships, and ii) negligible saturation of repair kinetics even for high doses. Additionally, we show that simulated radiation-induced persistent telomere-associated DNA damage foci (TAF) can be used to predict excess relative risk (ERR) of developing secondary leukemia after fractionated radiotherapy. We suggest that TAF may serve as an additional measure to predict cancer risk after radiotherapy using high dose rates. This may improve predicting risk-dose dependency of ionizing radiation especially for long-term therapies. PMID:26359627

  19. Development of a robust DNA damage model including persistent telomere-associated damage with application to secondary cancer risk assessment.

    PubMed

    Rastgou Talemi, Soheil; Kollarovic, Gabriel; Lapytsko, Anastasiya; Schaber, Jörg

    2015-01-01

    Mathematical modelling has been instrumental to understand kinetics of radiation-induced DNA damage repair and associated secondary cancer risk. The widely accepted two-lesion kinetic (TLK) model assumes two kinds of double strand breaks, simple and complex ones, with different repair rates. Recently, persistent DNA damage associated with telomeres was reported as a new kind of DNA damage. We therefore extended existing versions of the TLK model by new categories of DNA damage and re-evaluated those models using extensive data. We subjected different versions of the TLK model to a rigorous model discrimination approach. This enabled us to robustly select a best approximating parsimonious model that can both recapitulate and predict transient and persistent DNA damage after ionizing radiation. Models and data argue for i) nonlinear dose-damage relationships, and ii) negligible saturation of repair kinetics even for high doses. Additionally, we show that simulated radiation-induced persistent telomere-associated DNA damage foci (TAF) can be used to predict excess relative risk (ERR) of developing secondary leukemia after fractionated radiotherapy. We suggest that TAF may serve as an additional measure to predict cancer risk after radiotherapy using high dose rates. This may improve predicting risk-dose dependency of ionizing radiation especially for long-term therapies. PMID:26359627

  20. Mitochondrial damage in the soybean seed axis during imbibition at chilling temperatures.

    PubMed

    Yin, Guangkun; Sun, Hongmei; Xin, Xia; Qin, Guozheng; Liang, Zheng; Jing, Xinming

    2009-07-01

    The development of mitochondria during seed germination is essential for plant growth. However, the developmental process is still poorly understood. Temperature plays a key role in soybean germination, and in this study we characterized the mitochondrial ultrastructure and proteome after imbibition at 22, 10 and 4 degrees C for 24 h. The mitochondria from the soybean seed axis can be divided into light and heavy mitochondria by Percoll density gradient centrifugation. The axes imbibed at 4 degrees C mainly contained light mitochondria, which had lower levels of specific mitochondrial enzymes and oxidative phosphorylation activity. In contrast, the axes imbibed at 22 degrees C mainly contained heavy mitochondria, which exhibited higher metabolism. Electron microscopy revealed that mitochondria in the axes imbibed at 4 degrees C had a poorly developed internal membrane system with few cristae, while the mitochondria in the axes imbibed at 22 degrees C developed more normally. Furthermore, we compared the axis mitochondrial proteomes during imbibition at different temperatures. The differentially expressed proteins were identified using ESI-Q-TOF-MS/MS (electrospray ionization quadrupole time-of-flight tandem mass spectrometry). Proteins involved in mitochondrial metabolites including malate dehydrogenase (tricarboxylic acid cycle enzyme), putative ATP synthase subunit (oxidative phosphorylation complex subunits), mitochondrial chaperonin-60 (heat shock protein), arginase (urea cycle enzyme) and mitochondrial elongation factor Tu (mitochondrial genome transcript enzyme) were identified. The reduced expression of these proteins might not support normal mitochondrial metabolism. We conclude that chilling during imbibition causes mitochondrial damage at both ultrastructural and metabolic levels. PMID:19520672

  1. Mitochondrial Telomerase Protects Cancer Cells from Nuclear DNA Damage and Apoptosis

    PubMed Central

    Singhapol, Chatchawan; Pal, Deepali; Czapiewski, Rafal; Porika, Mahendar; Nelson, Glyn; Saretzki, Gabriele C.

    2013-01-01

    Most cancer cells express high levels of telomerase and proliferate indefinitely. In addition to its telomere maintenance function, telomerase also has a pro-survival function resulting in an increased resistance against DNA damage and decreased apoptosis induction. However, the molecular mechanisms for this protective function remain elusive and it is unclear whether it is connected to telomere maintenance or is rather a non-telomeric function of the telomerase protein, TERT. It was shown recently that the protein subunit of telomerase can shuttle from the nucleus to the mitochondria upon oxidative stress where it protects mitochondrial function and decreases intracellular oxidative stress. Here we show that endogenous telomerase (TERT protein) shuttles from the nucleus into mitochondria upon oxidative stress in cancer cells and analyzed the nuclear exclusion patterns of endogenous telomerase after treatment with hydrogen peroxide in different cell lines. Cell populations excluded TERT from the nucleus upon oxidative stress in a heterogeneous fashion. We found a significant correlation between nuclear localization of telomerase and high DNA damage, while cells which excluded telomerase from the nucleus displayed no or very low DNA damage. We modeled nuclear and mitochondrial telomerase using organelle specific localization vectors and confirmed that mitochondrial localization of telomerase protects the nucleus from inflicted DNA damage and apoptosis while, in contrast, nuclear localization of telomerase correlated with higher amounts of DNA damage and apoptosis. It is known that nuclear DNA damage can be caused by mitochondrially generated reactive oxygen species (ROS). We demonstrate here that mitochondrial localization of telomerase specifically prevents nuclear DNA damage by decreasing levels of mitochondrial ROS. We suggest that this decrease of oxidative stress might be a possible cause for high stress resistance of cancer cells and could be especially

  2. XPD localizes in mitochondria and protects the mitochondrial genome from oxidative DNA damage

    PubMed Central

    Liu, Jing; Fang, Hongbo; Chi, Zhenfen; Wu, Zan; Wei, Di; Mo, Dongliang; Niu, Kaifeng; Balajee, Adayabalam S.; Hei, Tom K.; Nie, Linghu; Zhao, Yongliang

    2015-01-01

    Xeroderma pigmentosum group D (XPD/ERCC2) encodes an ATP-dependent helicase that plays essential roles in both transcription and nucleotide excision repair of nuclear DNA, however, whether or not XPD exerts similar functions in mitochondria remains elusive. In this study, we provide the first evidence that XPD is localized in the inner membrane of mitochondria, and cells under oxidative stress showed an enhanced recruitment of XPD into mitochondrial compartment. Furthermore, mitochondrial reactive oxygen species production and levels of oxidative stress-induced mitochondrial DNA (mtDNA) common deletion were significantly elevated, whereas capacity for oxidative damage repair of mtDNA was markedly reduced in both XPD-suppressed human osteosarcoma (U2OS) cells and XPD-deficient human fibroblasts. Immunoprecipitation-mass spectrometry analysis was used to identify interacting factor(s) with XPD and TUFM, a mitochondrial Tu translation elongation factor was detected to be physically interacted with XPD. Similar to the findings in XPD-deficient cells, mitochondrial common deletion and oxidative damage repair capacity in U2OS cells were found to be significantly altered after TUFM knock-down. Our findings clearly demonstrate that XPD plays crucial role(s) in protecting mitochondrial genome stability by facilitating an efficient repair of oxidative DNA damage in mitochondria. PMID:25969448

  3. Focal damage to macaque photoreceptors produces persistent visual loss

    PubMed Central

    Strazzeri, Jennifer M.; Hunter, Jennifer J.; Masella, Benjamin D.; Yin, Lu; Fischer, William S.; DiLoreto, David A.; Libby, Richard T.; Williams, David R.; Merigan, William H.

    2014-01-01

    Insertion of light-gated channels into inner retina neurons restores neural light responses, light evoked potentials, visual optomotor responses and visually-guided maze behavior in mice blinded by retinal degeneration. This method of vision restoration bypasses damaged outer retina, providing stimulation directly to retinal ganglion cells in inner retina. The approach is similar to that of electronic visual protheses, but may offer some advantages, such as avoidance of complex surgery and direct targeting of many thousands of neurons. However, the promise of this technique for restoring human vision remains uncertain because rodent animal models, in which it has been largely developed, are not ideal for evaluating visual perception. On the other hand, psychophysical vision studies in macaque can be used to evaluate different approaches to vision restoration in humans. Furthermore, it has not been possible to test vision restoration in macaques, the optimal model for human-like vision, because there has been no macaque model of outer retina degeneration. In this study, we describe development of a macaque model of photoreceptor degeneration that can in future studies be used to test restoration of perception by visual prostheses. Our results show that perceptual deficits caused by focal light damage are restricted to locations at which photoreceptors are damaged, that optical coherence tomography (OCT) can be used to track such lesions, and that adaptive optics retinal imaging, which we recently used for in vivo recording of ganglion cell function, can be used in future studies to examine these lesions. PMID:24316158

  4. Focal damage to macaque photoreceptors produces persistent visual loss.

    PubMed

    Strazzeri, Jennifer M; Hunter, Jennifer J; Masella, Benjamin D; Yin, Lu; Fischer, William S; DiLoreto, David A; Libby, Richard T; Williams, David R; Merigan, William H

    2014-02-01

    Insertion of light-gated channels into inner retina neurons restores neural light responses, light evoked potentials, visual optomotor responses and visually-guided maze behavior in mice blinded by retinal degeneration. This method of vision restoration bypasses damaged outer retina, providing stimulation directly to retinal ganglion cells in inner retina. The approach is similar to that of electronic visual protheses, but may offer some advantages, such as avoidance of complex surgery and direct targeting of many thousands of neurons. However, the promise of this technique for restoring human vision remains uncertain because rodent animal models, in which it has been largely developed, are not ideal for evaluating visual perception. On the other hand, psychophysical vision studies in macaque can be used to evaluate different approaches to vision restoration in humans. Furthermore, it has not been possible to test vision restoration in macaques, the optimal model for human-like vision, because there has been no macaque model of outer retina degeneration. In this study, we describe development of a macaque model of photoreceptor degeneration that can in future studies be used to test restoration of perception by visual prostheses. Our results show that perceptual deficits caused by focal light damage are restricted to locations at which photoreceptors are damaged, that optical coherence tomography (OCT) can be used to track such lesions, and that adaptive optics retinal imaging, which we recently used for in vivo recording of ganglion cell function, can be used in future studies to examine these lesions. PMID:24316158

  5. Selective removal of persistent particles with no photomask damage

    NASA Astrophysics Data System (ADS)

    Robinson, Tod; Bozak, Ron; White, Roy; Archuletta, Mike; Lee, David

    2009-04-01

    Makers and users of advanced technology photomasks have seen increased difficulties with the removal of persistent, or stubborn, nano-particle contamination. Shrinking pattern geometries, and new mask clean technologies to minimize haze, have both increased the number of problems and loss of mask yield due to these non-removable nano-particles. A novel technique (BitCleanTM) has been developed using a scanning probe microscope system originally designed for nanomachining photomask defect repair. Progress in the technical development of this approach into a manufacture-able solution is reviewed and its effectiveness is shown in selectively removing adherent particles without touching surrounding sensitive structures. Methods for generating targeted edge test particles along with considerations for removal of particles in various pattern geometries and materials are also discussed.

  6. Assessment of mitochondrial DNA damage in little brown bats (Myotis lucifugus) collected near a mercury-contaminated river

    USGS Publications Warehouse

    Karouna-Renier, Natalie K.; White, Carl; Perkins, Christopher R.; Schmerfeld, John J.; Yates, David

    2014-01-01

    Historical discharges of Hg into the South River near the town of Waynesboro, VA, USA, have resulted in persistently elevated Hg concentrations in sediment, surface water, ground water, soil, and wildlife downstream of the discharge site. In the present study, we examined mercury (Hg) levels in in little brown bats (Myotis lucifugus) from this location and assessed the utility of a non-destructively collected tissue sample (wing punch) for determining mitochondrial DNA (mtDNA) damage in Hg exposed bats. Bats captured 1 and 3 km from the South River, exhibited significantly higher levels of total Hg (THg) in blood and fur than those from the reference location. We compared levels of mtDNA damage using real-time quantitative PCR (qPCR) analysis of two distinct regions of mtDNA. Genotoxicity is among the many known toxic effects of Hg, resulting from direct interactions with DNA or from oxidative damage. Because it lacks many of the protective protein structures and repair mechanisms associated with nuclear DNA, mtDNA is more sensitive to the effects of genotoxic chemicals and therefore may be a useful biomarker in chronically exposed organisms. Significantly higher levels of damage were observed in both regions of mtDNA in bats captured 3 km from the river than in controls. However, levels of mtDNA damage exhibited weak correlations with fur and blood THg levels, suggesting that other factors may play a role in the site-specific differences.

  7. Multiple mitochondrial DNA deletions and persistent hyperthermia in a patient with Brachmann-de Lange phenotype

    SciTech Connect

    Melegh, B.; Bock, I.; Mehes, K.

    1996-10-02

    In a newborn boy with characteristics of Brachmann-de Lange syndrome (BDLS), high temperatures were observed on the second day after birth and recurred 2-6 times daily during the 7 months of the patient`s life. After, transient hypertonia hypotonia developed. In muscle biopsy specimen taken on the 51st day of life, serious and progressive distortion of mitochondria was observed. In several mitochondria the cristae structure was broken, other mitochondria were shrunken and the damage progressed towards further deterioration in other organelles. At several points between the myofibrils, amorphous material was seen, possibly debris of destroyed mitochondria. Most myofibrils seemed to be intact; however, in some areas myolytic signs were present. Analysis of the mitochondrial DNA (mtDNA) showed multiple deletions in skeletal and heart muscles, liver, lung and kidney. Since the mtDNA encodes several proteins of the respiratory complexes, the deleted mtDNA certainly affected the integrity of the mitochondrial oxidative phosphorylation process by synthesis of abnormal proteins. In the present case the hyperthermia may have been a result of the mtDNA damage. 13 refs.

  8. Troglitazone, but not rosiglitazone, damages mitochondrial DNA and induces mitochondrial dysfunction and cell death in human hepatocytes

    SciTech Connect

    Rachek, Lyudmila I.; Yuzefovych, Larysa V.; LeDoux, Susan P.; Julie, Neil L.; Wilson, Glenn L.

    2009-11-01

    Thiazolidinediones (TZDs), such as troglitazone (TRO) and rosiglitazone (ROSI), improve insulin resistance by acting as ligands for the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARgamma). TRO was withdrawn from the market because of reports of serious hepatotoxicity. A growing body of evidence suggests that TRO caused mitochondrial dysfunction and induction of apoptosis in human hepatocytes but its mechanisms of action remain unclear. We hypothesized that damage to mitochondrial DNA (mtDNA) is an initiating event involved in TRO-induced mitochondrial dysfunction and hepatotoxicity. Primary human hepatocytes were exposed to TRO and ROSI. The results obtained revealed that TRO, but not ROSI at equimolar concentrations, caused a substantial increase in mtDNA damage and decreased ATP production and cellular viability. The reactive oxygen species (ROS) scavenger, N-acetyl cystein (NAC), significantly diminished the TRO-induced cytotoxicity, suggesting involvement of ROS in TRO-induced hepatocyte cytotoxicity. The PPARgamma antagonist (GW9662) did not block the TRO-induced decrease in cell viability, indicating that the TRO-induced hepatotoxicity is PPARgamma-independent. Furthermore, TRO induced hepatocyte apoptosis, caspase-3 cleavage and cytochrome c release. Targeting of a DNA repair protein to mitochondria by protein transduction using a fusion protein containing the DNA repair enzyme Endonuclease III (EndoIII) from Escherichia coli, a mitochondrial translocation sequence (MTS) and the protein transduction domain (PTD) from HIV-1 TAT protein protected hepatocytes against TRO-induced toxicity. Overall, our results indicate that significant mtDNA damage caused by TRO is a prime initiator of the hepatoxicity caused by this drug.

  9. Aldose Reductase-Mediated Phosphorylation of p53 Leads to Mitochondrial Dysfunction, and Damage in Diabetic Platelets

    PubMed Central

    Tang, Wai Ho; Stitham, Jeremiah; Jin, Yu; Liu, Renjing; Lee, Seung Hee; Du, Jing; Atteya, Gourg; Gleim, Scott; Spollett, Geralyn; Martin, Kathleen; Hwa, John

    2014-01-01

    Background Platelet abnormalities are well-recognized complications of diabetes mellitus (DM). Mitochondria play a central role in platelet metabolism and activation. Mitochondrial dysfunction is evident in DM. The molecular pathway for hyperglycemia-induced mitochondrial dysfunction in DM platelets is unknown. Methods and Results Using both human and humanized mouse models, we report that hyperglycemia-induced aldose reductase (AR) activation, and subsequent reactive oxygen species (ROS) production, leads to increased p53 phosphorylation (Ser15), which promotes mitochondrial dysfunction, damage and rupture by sequestration of the anti-apoptotic protein Bcl-xL. In a glucose dose dependent manner, severe mitochondrial damage leads to loss of mitochondrial membrane potential and platelet apoptosis (cytochrome c release, caspase 3 activation and phosphatidylserine exposure). Although platelet hyperactivation, mitochondrial dysfunction, AR activation, ROS production and p53 phosphorylation are all induced by hyperglycemia, we demonstrate that platelet apoptosis and hyperactivation are two distinct states, dependent upon the severity of the hyperglycemia and mitochondrial damage. Combined, both lead to increased thrombus formation in a mouse blood stasis model. Conclusions AR contributes to diabetes-mediated mitochondrial dysfunction and damage through the activation of p53. The degree of mitochondrial dysfunction and damage determines whether hyperactivity (mild damage) or apoptosis (severe damage) will ensue. These signaling components provide novel therapeutic targets for DM thrombotic complications. PMID:24474649

  10. Pathogenesis of Target Organ Damage in Hypertension: Role of Mitochondrial Oxidative Stress

    PubMed Central

    Rubattu, Speranza; Pagliaro, Beniamino; Pierelli, Giorgia; Santolamazza, Caterina; Di Castro, Sara; Mennuni, Silvia; Volpe, Massimo

    2014-01-01

    Hypertension causes target organ damage (TOD) that involves vasculature, heart, brain and kidneys. Complex biochemical, hormonal and hemodynamic mechanisms are involved in the pathogenesis of TOD. Common to all these processes is an increased bioavailability of reactive oxygen species (ROS). Both in vitro and in vivo studies explored the role of mitochondrial oxidative stress as a mechanism involved in the pathogenesis of TOD in hypertension, especially focusing on atherosclerosis, heart disease, renal failure, cerebrovascular disease. Both dysfunction of mitochondrial proteins, such as uncoupling protein-2 (UCP2), superoxide dismutase (SOD) 2, peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), calcium channels, and the interaction between mitochondria and other sources of ROS, such as NADPH oxidase, play an important role in the development of endothelial dysfunction, cardiac hypertrophy, renal and cerebral damage in hypertension. Commonly used anti-hypertensive drugs have shown protective effects against mitochondrial-dependent oxidative stress. Notably, few mitochondrial proteins can be considered therapeutic targets on their own. In fact, antioxidant therapies specifically targeted at mitochondria represent promising strategies to reduce mitochondrial dysfunction and related hypertensive TOD. In the present article, we discuss the role of mitochondrial oxidative stress as a contributing factor to hypertensive TOD development. We also provide an overview of mitochondria-based treatment strategies that may reveal useful to prevent TOD and reduce its progression. PMID:25561233

  11. Quercetin Attenuates Chronic Ethanol-Induced Hepatic Mitochondrial Damage through Enhanced Mitophagy

    PubMed Central

    Yu, Xiao; Xu, Yanyan; Zhang, Shanshan; Sun, Jian; Liu, Peiyi; Xiao, Lin; Tang, Yuhan; Liu, Liegang; Yao, Ping

    2016-01-01

    Emerging evidence suggested mitophagy activation mitigates ethanol-induced liver injury. However, the effect of ethanol on mitophagy is inconsistent. Importantly, the understanding of mitophagy status after chronic ethanol consumption is limited. This study evaluated the effect of quercetin, a naturally-occurring flavonoid, on chronic ethanol-induced mitochondrial damage focused on mitophagy. An ethanol regime to mice for 15 weeks (accounting for 30% of total calories) led to significant mitochondrial damage as evidenced by changes of the mitochondrial ultrastructure, loss of mitochondrial membrane potential and remodeling of membrane lipid composition, which was greatly attenuated by quercetin (100 mg/kg.bw). Moreover, quercetin blocked chronic ethanol-induced mitophagy suppression as denoted by mitophagosomes-lysosome fusion and mitophagy-related regulator elements, including LC3II, Parkin, p62 and voltage-dependent anion channel 1 (VDAC1), paralleling with increased FoxO3a nuclear translocation. AMP-activated protein kinase (AMPK) and extracellular signal regulated kinase 2 (ERK2), instead of AKT and Sirtuin 1, were involved in quercetin-mediated mitophagy activation. Quercetin alleviated ethanol-elicited mitochondrial damage through enhancing mitophagy, highlighting a promising preventive strategy for alcoholic liver disease. PMID:26742072

  12. Inhibition of Soluble Epoxide Hydrolase Limits Mitochondrial Damage and Preserves Function Following Ischemic Injury

    PubMed Central

    Akhnokh, Maria K.; Yang, Feng Hua; Samokhvalov, Victor; Jamieson, Kristi L.; Cho, Woo Jung; Wagg, Cory; Takawale, Abhijit; Wang, Xiuhua; Lopaschuk, Gary D.; Hammock, Bruce D.; Kassiri, Zamaneh; Seubert, John M.

    2016-01-01

    Aims: Myocardial ischemia can result in marked mitochondrial damage leading to cardiac dysfunction, as such identifying novel mechanisms to limit mitochondrial injury is important. This study investigated the hypothesis that inhibiting soluble epoxide hydrolase (sEH), responsible for converting epoxyeicosatrienoic acids to dihydroxyeicosatrienoic acids protects mitochondrial from injury caused by myocardial infarction. Methods: sEH null and WT littermate mice were subjected to surgical occlusion of the left anterior descending (LAD) artery or sham operation. A parallel group of WT mice received an sEH inhibitor, trans-4-[4-(3-adamantan-1-y1-ureido)-cyclohexyloxy]-benzoic acid (tAUCB; 10 mg/L) or vehicle in the drinking water 4 days prior and 7 days post-MI. Cardiac function was assessed by echocardiography prior- and 7-days post-surgery. Heart tissues were dissected into infarct, peri-, and non-infarct regions to assess ultrastructure by electron microscopy. Complexes I, II, IV, citrate synthase, PI3K activities, and mitochondrial respiration were assessed in non-infarct regions. Isolated working hearts were used to measure the rates of glucose and palmitate oxidation. Results: Echocardiography revealed that tAUCB treatment or sEH deficiency significantly improved systolic and diastolic function post-MI compared to controls. Reduced infarct expansion and less adverse cardiac remodeling were observed in tAUCB-treated and sEH null groups. EM data demonstrated mitochondrial ultrastructure damage occurred in infarct and peri-infarct regions but not in non-infarct regions. Inhibition of sEH resulted in significant improvements in mitochondrial respiration, ATP content, mitochondrial enzymatic activities and restored insulin sensitivity and PI3K activity. Conclusion: Inhibition or genetic deletion of sEH protects against long-term ischemia by preserving cardiac function and maintaining mitochondrial efficiency. PMID:27375480

  13. Persistence of mitochondrial DNA markers as fecal indicators in water environments.

    PubMed

    He, Xiwei; Chen, Huimei; Shi, Wei; Cui, Yibin; Zhang, Xu-Xiang

    2015-11-15

    Mitochondrial DNA (mtDNA) polymerase chain reaction (PCR) technology has recently been developed to identify sources of fecal contamination, but information regarding environmental fate of mtDNA is limited. In this study, quantitative real-time PCR was used to determine the persistence of three species-specific mtDNA markers (human, pig and chicken) in river microcosms under different laboratory conditions and in dialysis tubes incubated in river environments during different seasons. Human feces had a higher abundance of mtDNA marker than pig and chicken feces. A biphasic decay pattern was observed for the mtDNA markers in microcosms incubated in darkness, and T90 (time needed for 90% reduction) ranged from 2.03 to 13.83 d. Each species-specific mtDNA marker persisted for relatively longer time at lower temperatures, and light exposure and predation increased the decay rates. Field experiments showed that the mtDNA markers could survive for longer time in winter (T90: 1.79-4.37 d) than in summer (T90: 0.60-0.75 d). Field application of mtDNA technology indicated that the markers were mainly distributed on the sites near animal breeding plants and had lower abundance in downstream water of the receiving river. This study expands our knowledge of the environmental fate of mtDNA markers and the results may be useful for practical application of the technology in fecal source tracking. PMID:26172605

  14. 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. PMID:25962994

  15. Deletion of conserved protein phosphatases reverses defects associated with mitochondrial DNA damage in Saccharomyces cerevisiae.

    PubMed

    Garipler, Görkem; Mutlu, Nebibe; Lack, Nathan A; Dunn, Cory D

    2014-01-28

    Mitochondrial biogenesis is regulated by signaling pathways sensitive to extracellular conditions and to the internal environment of the cell. Therefore, treatments for disease caused by mutation of mtDNA may emerge from studies of how signal transduction pathways command mitochondrial function. We have examined the role of phosphatases under the control of the conserved α4/Tap42 protein in cells lacking a mitochondrial genome. We found that deletion of protein phosphatase 2A (PP2A) or of protein phosphatase 6 (PP6) protects cells from the reduced proliferation, mitochondrial protein import defects, lower mitochondrial electrochemical potential, and nuclear transcriptional response associated with mtDNA damage. Moreover, PP2A or PP6 deletion allows viability of a sensitized yeast strain after mtDNA loss. Interestingly, the Saccharomyces cerevisiae ortholog of the mammalian AMP-activated protein kinase was required for the full benefits of PP6 deletion and also for proliferation of otherwise wild-type cells lacking mtDNA. Our work highlights the important role that nutrient-responsive signaling pathways can play in determining the response to mitochondrial dysfunction. PMID:24474773

  16. Screening SIRT1 Activators from Medicinal Plants as Bioactive Compounds against Oxidative Damage in Mitochondrial Function

    PubMed Central

    Wang, Yi; Liang, Xinying; Chen, Yaqi; Zhao, Xiaoping

    2016-01-01

    Sirtuin type 1 (SIRT1) belongs to the family of NAD+ dependent histone deacetylases and plays a critical role in cellular metabolism and response to oxidative stress. Traditional Chinese medicines (TCMs), as an important part of natural products, have been reported to exert protective effect against oxidative stress in mitochondria. In this study, we screened SIRT1 activators from TCMs and investigated their activities against mitochondrial damage. 19 activators were found in total by in vitro SIRT1 activity assay. Among those active compounds, four compounds, ginsenoside Rb2, ginsenoside F1, ginsenoside Rc, and schisandrin A, were further studied to validate the SIRT1-activation effects by liquid chromatography-mass spectrometry and confirm their activities against oxidative damage in H9c2 cardiomyocytes exposed to tert-butyl hydroperoxide (t-BHP). The results showed that those compounds enhanced the deacetylated activity of SIRT1, increased ATP content, and inhibited intracellular ROS formation as well as regulating the activity of Mn-SOD. These SIRT1 activators also showed moderate protective effects on mitochondrial function in t-BHP cells by recovering oxygen consumption and increasing mitochondrial DNA content. Our results suggested that those compounds from TCMs attenuated oxidative stress-induced mitochondrial damage in cardiomyocytes through activation of SIRT1. PMID:26981165

  17. Mitochondrial DNA damage is associated with damage accrual and disease duration in patients with Systemic Lupus Erythematosus

    PubMed Central

    López-López, Linnette; Nieves-Plaza, Mariely; Castro, María del R.; Font, Yvonne M.; Torres-Ramos, Carlos; Vilá, Luis M.; Ayala-Peña, Sylvette

    2014-01-01

    Objective To determine the extent of mitochondrial DNA (mtDNA) damage in systemic lupus erythematosus (SLE) patients compared to healthy subjects and to determine the factors associated with mtDNA damage among SLE patients. Methods A cross-sectional study was performed in 86 SLE patients (per American College of Rheumatology classification criteria) and 86 healthy individuals matched for age and gender. Peripheral blood mononuclear cells (PBMCs) were collected from subjects to assess the relative amounts of mtDNA damage. Quantitative polymerase chain reaction assay was used to measure the frequency of mtDNA lesions and mtDNA abundance. Socioeconomic-demographic features, clinical manifestations, pharmacologic treatment, disease activity, and damage accrual were determined. Statistical analyses were performed using t test, pairwise correlation, and Pearson’s chi-square test (or Fisher’s exact test) as appropriate. Results Among SLE patients, 93.0% were women. The mean (SD) age was 38.0 (10.4) years and the mean (SD) disease duration was 8.7 (7.5) years. SLE patients exhibited increased levels of mtDNA damage as shown by higher levels of mtDNA lesions and decreased mtDNA abundance as compared to healthy individuals. There was a negative correlation between disease damage and mtDNA abundance and a positive correlation between mtDNA lesions and disease duration. No association was found between disease activity and mtDNA damage. Conclusion PBMCs from SLE patients exhibited more mtDNA damage compared to healthy subjects. Higher levels of mtDNA damage were observed among SLE patients with major organ involvement and damage accrual. These results suggest that mtDNA damage have a potential role in the pathogenesis of SLE. PMID:24899636

  18. Role of oxidative DNA damage in mitochondrial dysfunction and Huntington's disease pathogenesis.

    PubMed

    Ayala-Peña, Sylvette

    2013-09-01

    Huntington's disease (HD) is a neurodegenerative disorder with an autosomal dominant expression pattern and typically a late-onset appearance. HD is a movement disorder with a heterogeneous phenotype characterized by involuntary dance-like gait, bioenergetic deficits, motor impairment, and cognitive and psychiatric deficits. Compelling evidence suggests that increased oxidative stress and mitochondrial dysfunction may underlie HD pathogenesis. However, the exact mechanisms underlying mutant huntingtin-induced neurological toxicity remain unclear. The objective of this paper is to review recent literature regarding the role of oxidative DNA damage in mitochondrial dysfunction and HD pathogenesis. PMID:23602907

  19. Profiling mitochondrial proteins in radiation-induced genome-unstable cell lines with persistent oxidative stress by mass spectrometry

    SciTech Connect

    Miller, John H.; Jin, Shuangshuang; Morgan, William F.; Yang, Austin; Wan, Yunhu; Aypar, Umut; Peters, Jonathan S.; Springer, David L.

    2008-06-01

    Radiation-induced genome instability (RIGI) is a response to radiation exposure in which the progeny of surviving cells exhibit increased frequency of chromosomal changes many generations after the initial insult. Persistently elevated oxidative stress accompanying RIGI and the ability of free-radical scavengers, given before irradiation, to reduce the incidence of instability suggest that radiation induced alterations to mitochondrial function likely play a role in RIGI. To further elucidate this mechanism, we performed high-throughput quantitative mass spectrometry on samples enriched in mitochondrial proteins from three chromosomally-unstable GM10115 Chinese-hamster-ovary cell lines and their stable parental cell line. Out of several hundred identified proteins, sufficient data were collected on 74 mitochondrial proteins to test for statistically significant differences in their abundance between unstable and stable cell lines. Each of the unstable cell lines showed a distinct profile of statistically-significant differential abundant mitochondrial proteins. The LS-12 cell line was characterized by 8 downregulated proteins, whereas the CS-9 cell line exhibited 5 distinct up-regulated proteins. The unstable 115 cell line had two down-regulated proteins, one of which was also downregulated in LS-12, and one up-regulated protein relative to stable parental cells. The mitochondrial protein profiles for LS-12 and C-9 provide further evidence that mitochondrial dysfunction is involved in the genome instability of these cell lines.

  20. Mechanisms of MDMA (ecstasy)-induced oxidative stress, mitochondrial dysfunction, and organ damage.

    PubMed

    Song, Byoung-Joon; Moon, Kwan-Hoon; Upreti, Vijay V; Eddington, Natalie D; Lee, Insong J

    2010-08-01

    Despite numerous reports about the acute and sub-chronic toxicities caused by MDMA (3,4-methylenedioxymethamphetamine, ecstasy), the underlying mechanism of organ damage is poorly understood. The aim of this review is to present an update of the mechanistic studies on MDMA-mediated organ damage partly caused by increased oxidative/nitrosative stress. Because of the extensive reviews on MDMA-mediated oxidative stress and tissue damage, we specifically focus on the mechanisms and consequences of oxidative-modifications of mitochondrial proteins, leading to mitochondrial dysfunction. We briefly describe a method to systematically identify oxidatively-modified mitochondrial proteins in control and MDMA-exposed rats by using biotin-N-maleimide (biotin-NM) as a sensitive probe for oxidized proteins. We also describe various applications and advantages of this Cys-targeted proteomics method and alternative approaches to overcome potential limitations of this method in studying oxidized proteins from MDMA-exposed tissues. Finally we discuss the mechanism of synergistic drug-interaction between MDMA and other abused substances including alcohol (ethanol) as well as application of this redox-based proteomics method in translational studies for developing effective preventive and therapeutic agents against MDMA-induced organ damage. PMID:20420575

  1. Over-expression of heme oxygenase-1 promotes oxidative mitochondrial damage in rat astroglia.

    PubMed

    Song, Wei; Su, Haixiang; Song, Sisi; Paudel, Hemant K; Schipper, Hyman M

    2006-03-01

    Glial heme oxygenase-1 is over-expressed in the CNS of subjects with Alzheimer disease (AD), Parkinson disease (PD) and multiple sclerosis (MS). Up-regulation of HO-1 in rat astroglia has been shown to facilitate iron sequestration by the mitochondrial compartment. To determine whether HO-1 induction promotes mitochondrial oxidative stress, assays for 8-epiPGF(2alpha) (ELISA), protein carbonyls (ELISA) and 8-OHdG (HPLC-EC) were used to quantify oxidative damage to lipids, proteins, and nucleic acids, respectively, in mitochondrial fractions and whole-cell compartments derived from cultured rat astroglia engineered to over-express human (h) HO-1 by transient transfection. Cell viability was assessed by trypan blue exclusion and the MTT assay, and cell proliferation was determined by [3H] thymidine incorporation and total cell counts. In rat astrocytes, hHO-1 over-expression (x 3 days) resulted in significant oxidative damage to mitochondrial lipids, proteins, and nucleic acids, partial growth arrest, and increased cell death. These effects were attenuated by incubation with 1 microM tin mesoporphyrin, a competitive HO inhibitor, or the iron chelator, deferoxamine. Up-regulation of HO-1 engenders oxidative mitochondrial injury in cultured rat astroglia. Heme-derived ferrous iron and carbon monoxide (CO) may mediate the oxidative modification of mitochondrial lipids, proteins and nucleic acids in these cells. Glial HO-1 hyperactivity may contribute to cellular oxidative stress, pathological iron deposition, and bioenergetic failure characteristic of degenerating and inflamed neural tissues and may constitute a rational target for therapeutic intervention in these conditions. PMID:16222706

  2. Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage.

    PubMed Central

    Li, Ning; Sioutas, Constantinos; Cho, Arthur; Schmitz, Debra; Misra, Chandan; Sempf, Joan; Wang, Meiying; Oberley, Terry; Froines, John; Nel, Andre

    2003-01-01

    The objectives of this study were to determine whether differences in the size and composition of coarse (2.5-10 micro m), fine (< 2.5 microm), and ultrafine (< 0.1 microm) particulate matter (PM) are related to their uptake in macrophages and epithelial cells and their ability to induce oxidative stress. The premise for this study is the increasing awareness that various PM components induce pulmonary inflammation through the generation of oxidative stress. Coarse, fine, and ultrafine particles (UFPs) were collected by ambient particle concentrators in the Los Angeles basin in California and used to study their chemical composition in parallel with assays for generation of reactive oxygen species (ROS) and ability to induce oxidative stress in macrophages and epithelial cells. UFPs were most potent toward inducing cellular heme oxygenase-1 (HO-1) expression and depleting intracellular glutathione. HO-1 expression, a sensitive marker for oxidative stress, is directly correlated with the high organic carbon and polycyclic aromatic hydrocarbon (PAH) content of UFPs. The dithiothreitol (DTT) assay, a quantitative measure of in vitro ROS formation, was correlated with PAH content and HO-1 expression. UFPs also had the highest ROS activity in the DTT assay. Because the small size of UFPs allows better tissue penetration, we used electron microscopy to study subcellular localization. UFPs and, to a lesser extent, fine particles, localize in mitochondria, where they induce major structural damage. This may contribute to oxidative stress. Our studies demonstrate that the increased biological potency of UFPs is related to the content of redox cycling organic chemicals and their ability to damage mitochondria. PMID:12676598

  3. Cockayne syndrome group B protein prevents the accumulation of damaged mitochondria by promoting mitochondrial autophagy

    PubMed Central

    Scheibye-Knudsen, Morten; Ramamoorthy, Mahesh; Sykora, Peter; Maynard, Scott; Lin, Ping-Chang; Minor, Robin K.; Wilson III, David M.; Cooper, Marcus; Spencer, Richard; de Cabo, Rafael; Croteau, Deborah L.

    2012-01-01

    Cockayne syndrome (CS) is a devastating autosomal recessive disease characterized by neurodegeneration, cachexia, and accelerated aging. 80% of the cases are caused by mutations in the CS complementation group B (CSB) gene known to be involved in DNA repair and transcription. Recent evidence indicates that CSB is present in mitochondria, where it associates with mitochondrial DNA (mtDNA). We report an increase in metabolism in the CSBm/m mouse model and CSB-deficient cells. Mitochondrial content is increased in CSB-deficient cells, whereas autophagy is down-regulated, presumably as a result of defects in the recruitment of P62 and mitochondrial ubiquitination. CSB-deficient cells show increased free radical production and an accumulation of damaged mitochondria. Accordingly, treatment with the autophagic stimulators lithium chloride or rapamycin reverses the bioenergetic phenotype of CSB-deficient cells. Our data imply that CSB acts as an mtDNA damage sensor, inducing mitochondrial autophagy in response to stress, and that pharmacological modulators of autophagy are potential treatment options for this accelerated aging phenotype. PMID:22473955

  4. Cyclovirobuxine D Attenuates Doxorubicin-Induced Cardiomyopathy by Suppression of Oxidative Damage and Mitochondrial Biogenesis Impairment

    PubMed Central

    Guo, Qian; Guo, Jiabin; Yang, Rong; Peng, Hui; Zhao, Jun; Li, Li; Peng, Shuangqing

    2015-01-01

    The clinical application of doxorubicin (DOX) is compromised by its cardiac toxic effect. Cyclovirobuxine D (CVB-D) is a steroid alkaloid extracted from a traditional Chinese medicine, Buxus microphylla. Our results showed that CVB-D pretreatment markedly attenuated DOX-induced cardiac contractile dysfunction and histological alterations. By using TUNEL assay and western blot analysis, we found that CVB-D pretreatment reduced DOX-induced apoptosis of myocardial cells and mitochondrial cytochrome c release to cytosol. CVB-D pretreatment ameliorated DOX-induced cardiac oxidative damage including lipid peroxidation and protein carbonylation and a decrease in the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Moreover, CVB-D was found to prevent DOX-induced mitochondrial biogenesis impairment as evidenced by preservation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and nuclear respiratory factor 1 (NRF1), as well as mitochondrial DNA copy number. These findings demonstrate that CVB-D protects against DOX-induced cardiomyopathy, at least in part, by suppression of oxidative damage and mitochondrial biogenesis impairment. PMID:26075032

  5. The mitochondrial theory of aging: do damaged mitochondria accumulate by delayed degradation?

    PubMed

    Kowald, A

    1999-08-01

    The mitochondrial theory of aging states that the slow accumulation of impaired mitochondria is the driving force of the aging process. In recent years, this theory has gained new support with the discovery of age-related mitochondrial DNA deletions. However, the underlying mechanism of the accumulation of defective mitochondria remained unclear. This has changed recently with the proposal of de Grey that damaged mitochondria have a decreased degradation rate. The resulting increase in biological half-life would be a strong selection advantage leading to the accumulation of defective mitochondria. In this article, I summarize current ideas on how damaged organelles can build up in a cell as well as the shortcomings of these ideas. Then the new hypothesis and its justification are described. It appears that de Grey's hypothesis is a very promising concept that elegantly solves inconsistencies of current models and is in accordance with experimental findings. PMID:10530786

  6. Oxidative Stress Induces Persistent Telomeric DNA Damage Responsible for Nuclear Morphology Change in Mammalian Cells

    PubMed Central

    Coluzzi, Elisa; Colamartino, Monica; Cozzi, Renata; Leone, Stefano; Meneghini, Carlo; O’Callaghan, Nathan; Sgura, Antonella

    2014-01-01

    One main function of telomeres is to maintain chromosome and genome stability. The rate of telomere shortening can be accelerated significantly by chemical and physical environmental agents. Reactive oxygen species are a source of oxidative stress and can produce modified bases (mainly 8-oxoG) and single strand breaks anywhere in the genome. The high incidence of guanine residues in telomeric DNA sequences makes the telomere a preferred target for oxidative damage. Our aim in this work is to evaluate whether chromosome instability induced by oxidative stress is related specifically to telomeric damage. We treated human primary fibroblasts (MRC-5) in vitro with hydrogen peroxide (100 and 200 µM) for 1 hr and collected data at several time points. To evaluate the persistence of oxidative stress-induced DNA damage up to 24 hrs after treatment, we analysed telomeric and genomic oxidative damage by qPCR and a modified comet assay, respectively. The results demonstrate that the genomic damage is completely repaired, while the telomeric oxidative damage persists. The analysis of telomere length reveals a significant telomere shortening 48 hrs after treatment, leading us to hypothesise that residual telomere damage could be responsible for the telomere shortening observed. Considering the influence of telomere length modulation on genomic stability, we quantified abnormal nuclear morphologies (Nucleoplasmic Bridges, Nuclear Buds and Micronuclei) and observed an increase of chromosome instability in the same time frame as telomere shortening. At subsequent times (72 and 96 hrs), we observed a restoration of telomere length and a reduction of chromosome instability, leaving us to conjecture a correlation between telomere shortening/dysfunction and chromosome instability. We can conclude that oxidative base damage leads to abnormal nuclear morphologies and that telomere dysfunction is an important contributor to this effect. PMID:25354277

  7. Defects associated with mitochondrial DNA damage can be mitigated by increased vacuolar pH in Saccharomyces cerevisiae.

    PubMed

    Garipler, Görkem; Dunn, Cory D

    2013-05-01

    While searching for mutations that alleviate detrimental effects of mitochondrial DNA (mtDNA) damage, we found that disrupting vacuolar biogenesis permitted survival of a sensitized yeast background after mitochondrial genome loss. Furthermore, elevating vacuolar pH increases proliferation after mtDNA deletion and reverses the protein import defect of mitochondria lacking DNA. PMID:23502676

  8. QPCR: a tool for analysis of mitochondrial and nuclear DNA damage in ecotoxicology.

    PubMed

    Meyer, Joel N

    2010-04-01

    The quantitative PCR (QPCR) assay for DNA damage and repair has been used extensively in laboratory species. More recently, it has been adapted to ecological settings. The purpose of this article is to provide a detailed methodological guide that will facilitate its adaptation to additional species, highlight its potential for ecotoxicological and biomonitoring work, and critically review the strengths and limitations of this assay. Major strengths of the assay include very low (nanogram to picogram) amounts of input DNA; direct comparison of damage and repair in the nuclear and mitochondrial genomes, and different parts of the nuclear genome; detection of a wide range of types of DNA damage; very good reproducibility and quantification; applicability to properly preserved frozen samples; simultaneous monitoring of relative mitochondrial genome copy number; and easy adaptation to most species. Potential limitations include the limit of detection (approximately 1 lesion per 10(5) bases); the inability to distinguish different types of DNA damage; and the need to base quantification of damage on a control or reference sample. I suggest that the QPCR assay is particularly powerful for some ecotoxicological studies. PMID:20049526

  9. [Exercise training in hypoxia prevents hypoxia induced mitochondrial DNA oxidative damage in skeletal muscle].

    PubMed

    Bo, Hai; Li, Ling; Duan, Fu-Qiang; Zhu, Jiang

    2014-10-25

    This study was undertaken to investigate the effect of exercise training on mitochondrial DNA (mtDNA) oxidative damage and 8-oxoguanine DNA glycosylase-1 (OGG1) expression in skeletal muscle of rats under continuous exposure to hypoxia. Male Sprague-Dawley rats were randomly divided into 4 groups (n = 8): normoxia control group (NC), normoxia training group (NT), hypoxia control group (HC), and hypoxia training group (HT). The hypoxia-treated animals were housed in normobaric hypoxic tent containing 11.3% oxygen for consecutive 4 weeks. The exercise-trained animals were exercised on a motor-driven rodent treadmill at a speed of 15 m/min, 5% grade for 60 min/day, 5 days per week for 4 weeks. The results showed that, compared with NC group, hypoxia attenuated complex I, II, IV and ATP synthase activities of the electron transport chain, and the level of mitochondrial membrane potential in HC group (P < 0.05 or P < 0.01). Moreover, hypoxia decreased mitochondrial OGG1, MnSOD, and GPx activities (P < 0.05 or P < 0.01), whereas elevated reactive oxygen species (ROS) generation and the level of 8-oxo-deoxyguanosine (8-oxodG) in mtDNA (P < 0.01). Furthermore, hypoxia attenuated muscle and mitochondrial [NAD⁺]/ [NADH] ratio, and SIRT3 protein expression (P < 0.05 or P < 0.01). Compared with HC group, exercise training in hypoxia elevated complex I, II, IV and ATP synthase activities, and the level of mitochondrial membrane potential in HT group (P < 0.05 or P < 0.01). Moreover, exercise training in hypoxia increased MnSOD and GPx activities and mitochondrial OGG1 level (P < 0.01), whereas decreased ROS generation and the level of 8-oxodG in mtDNA (P < 0.01). Furthermore, exercise training in hypoxia increased muscle and mitochondrial [NAD⁺]/[NADH] ratio, as well as SIRT3 protein expression (P < 0.05 or P < 0.01). These findings suggest that exercise training in hypoxia can decrease hypoxia-induced mtDNA oxidative damage in the skeletal muscle through up

  10. Persistent Bloodstream Infection with Kocuria rhizophila Related to a Damaged Central Catheter

    PubMed Central

    Becker, Karsten; Mérens, Audrey; Ferroni, Agnès; Dubern, Béatrice; Vu-Thien, Hoang

    2012-01-01

    A case of persistent bloodstream infection with Kocuria rhizophila related to a damaged central venous catheter in a 3-year-old girl with Hirschsprung's disease is reported. The strain was identified as K. rhizophila by 16S rRNA gene sequencing and matrix-assisted laser desorption ionization–time of flight mass spectrometry. Arbitrarily primed PCR analysis showed a clonal strain. The repeated septic episodes were resolved with the catheter repair. PMID:22259211

  11. Inhibition of the mitochondrial respiratory chain function abrogates quartz induced DNA damage in lung epithelial cells.

    PubMed

    Li, Hui; Haberzettl, Petra; Albrecht, Catrin; Höhr, Doris; Knaapen, Ad M; Borm, Paul J A; Schins, Roel P F

    2007-04-01

    Respirable quartz dust has been classified as a human carcinogen by the International Agency for Research on Cancer. The aim of our study was to investigate the mechanisms of DNA damage by DQ12 quartz in RLE-6TN rat lung epithelial type II cells (RLE). Transmission electron microscopy and flow-cytometry analysis showed a rapid particle uptake (30 min to 4 h) of quartz by the RLE cells, but particles were not found within the cell nuclei. This suggests that DNA strand breakage and induction of 8-hydroxydeoxyguanosine - as also observed in these cells during these treatment intervals - did not result from direct physical interactions between particles and DNA, or from short-lived particle surface-derived reactive oxygen species. DNA damage by quartz was significantly reduced in the presence of the mitochondrial inhibitors rotenone and antimycin-A. In the absence of quartz, these inhibitors did not affect DNA damage, but they reduced cellular oxygen consumption. No signs of apoptosis were observed by quartz. Flow-cytometry analysis indicated that the reduced DNA damage by rotenone was not due to a possible mitochondria-mediated reduction of particle uptake by the RLE cells. Further proof of concept for the role of mitochondria was shown by the failure of quartz to elicit DNA damage in mitochondria-depleted 143B (rho-0) osteosarcoma cells, at concentrations where it elicited DNA damage in the parental 143B cell line. In conclusion, our data show that respirable quartz particles can elicit oxidative DNA damage in vitro without entering the nuclei of type II cells, which are considered to be important target cells in quartz carcinogenesis. Furthermore, our observations indicate that such indirect DNA damage involves the mitochondrial electron transport chain function, by an as-yet-to-be elucidated mechanism. PMID:17239409

  12. Mitochondrial ferritin suppresses MPTP-induced cell damage by regulating iron metabolism and attenuating oxidative stress.

    PubMed

    You, Lin-Hao; Li, Zhen; Duan, Xiang-Lin; Zhao, Bao-Lu; Chang, Yan-Zhong; Shi, Zhen-Hua

    2016-07-01

    Our previous work showed that mitochondrial ferritin (MtFt) played an important role in preventing neuronal damage in 6-OHDA-induced Parkinson's disease (PD). However, the role of MtFt in a PD model induced by MPTP is not clear. Here, we found that methyl-4-phenyl-1, 2, 3, 6-tetra-pyridine (MPTP) significantly upregulated MtFt in the mouse hippocampus, substantia nigra (SN) and striatum. To explore the effect of MtFt upregulation on the MPTP-mediated injury to neural cells, MtFt-/- mice and MtFt-overexpressing cells were used to construct models of PD induced by MPTP. Our results showed that MPTP dramatically downregulated expression of transferrin receptor 1 (TfR1) and tyrosine hydroxylase and upregulated L-ferritin expression in the mouse striatum and SN. Interestingly, MPTP induced high levels of MtFt in these tissues, indicating that MtFt was involved in iron metabolism and influenced dopamine synthesis induced by MPTP. Meanwhile, the Bcl2/Bax ratio was decreased significantly by MPTP in the striatum and SN of MtFt knockout (MtFt-/-) mice compared with controls. Overexpression of MtFt increased TfR1 and decreased ferroportin 1 induced by 1-methyl-4-phenylpyridinium ions (MPP+). MtFt strongly inhibited mitochondrial damage through maintaining the mitochondrial membrane potential and protecting the integrity of the mitochondrial membrane. It also suppressed the increase of the labile iron pool, decreased production of reactive oxygen species and dramatically rescued the apoptosis induced by MPP+. In conclusion, this study demonstrates that MtFt plays an important role in preventing neuronal damage in the MPTP-induced parkinsonian phenotype by inhibiting cellular iron accumulation and subsequent oxidative stress. PMID:27017962

  13. Mitochondrial Peroxiredoxin-3 protects against hyperglycemia induced myocardial damage in Diabetic cardiomyopathy.

    PubMed

    Arkat, Silpa; Umbarkar, Prachi; Singh, Sarojini; Sitasawad, Sandhya L

    2016-08-01

    Mitochondrial oxidative stress has emerged as a key contributor towards the development of diabetic cardiomyopathy. Peroxiredoxin-3 (Prx-3), a mitochondrial antioxidant, scavenges H2O2 and offers protection against ROS related pathologies. We observed a decrease in the expression of Prx-3 in the hearts of streptozotocin (STZ) induced diabetic rats, and also high glucose treated H9c2 cardiac cells, which may augment oxidative stress mediated damage. Hence we hypothesized that overexpression of Prx-3 could prevent the cardiac damage associated with diabetes. In this study we used quercetin (QUE) to achieve Prx-3 induction in vivo, while a Prx-3 overexpressing H9c2 cell line was employed for carrying out in vitro studies. Diabetes was induced in Wistar rats by a single intraperitoneal injection of STZ. Quercetin (50mg/kg body weight) was delivered orally to hyperglycemic and age matched control rats for 2 months. Quercetin treatment induced the myocardial expression of Prx-3 but not Prx-5 both in control and STZ rats. Prx-3 induction by quercetin prevented diabetes induced oxidative stress as confirmed by decrease in expression of markers such as 4-HNE and mitochondrial uncoupling protein, UCP-3. It was also successful in reducing cardiac cell apoptosis, hypertrophy and fibrosis leading to amelioration of cardiac contractility defects. Overexpression of Prx-3 in cultured H9c2 cardiac cells could significantly diminish high glucose inflicted mitochondrial oxidative damage and apoptosis, thus strengthening our hypothesis. These results suggest that diabetes induced cardiomyopathy can be prevented by elevating Prx-3 levels thereby providing extensive protection to the diabetic heart. PMID:27393003

  14. Naringin protects memory impairment and mitochondrial oxidative damage against aluminum-induced neurotoxicity in rats.

    PubMed

    Prakash, Atish; Shur, Bhargabi; Kumar, Anil

    2013-09-01

    Aluminum has been indicated in neurodegenerative disorders and naringin, a bioflavonoid has been used to reduce neurotoxic effects of aluminum against aluminum chloride-induced rats. Therefore, present study has been designed to explore the possible role of naringin against aluminum-induced cognitive dysfunction and oxidative damage in rats. Aluminum (100 mg/kg) and naringin (40 and 80 mg/kg) drug treatment were administered orally for six weeks to male wistar rats. Various behavioral performance tasks, biochemical, mitochondrial oxidative parameters, and aluminum concentration in the brain were assessed. Aluminum chloride treatment significantly caused cognitive dysfunction and mitochondria oxidative damage as compared to vehicle treated control group. Besides, aluminum chloride treatment significantly increased acetyl cholinesterase activity and aluminum concentration in the brain as compared to sham. Chronic administration of naringin significantly improved cognitive performance and attenuated mitochondria oxidative damage, acetyl cholinesterase activity, and aluminum concentration in aluminum-treated rats as compared to control rats. Results of the study demonstrate neuroprotective potential of naringin against aluminum chloride-induced cognitive dysfunction and mitochondrial oxidative damage. PMID:23510099

  15. Endoplasmic Reticulum Stress Activates the Inflammasome via NLRP3- and Caspase-2-Driven Mitochondrial Damage.

    PubMed

    Bronner, Denise N; Abuaita, Basel H; Chen, Xiaoyun; Fitzgerald, Katherine A; Nuñez, Gabriel; He, Yongqun; Yin, Xiao-Ming; O'Riordan, Mary X D

    2015-09-15

    Endoplasmic reticulum (ER) stress is observed in many human diseases, often associated with inflammation. ER stress can trigger inflammation through nucleotide-binding domain and leucine-rich repeat containing (NLRP3) inflammasome, which might stimulate inflammasome formation by association with damaged mitochondria. How ER stress triggers mitochondrial dysfunction and inflammasome activation is ill defined. Here we have used an infection model to show that the IRE1α ER stress sensor regulates regulated mitochondrial dysfunction through an NLRP3-mediated feed-forward loop, independently of ASC. IRE1α activation increased mitochondrial reactive oxygen species, promoting NLRP3 association with mitochondria. NLRP3 was required for ER stress-induced cleavage of caspase-2 and the pro-apoptotic factor, Bid, leading to subsequent release of mitochondrial contents. Caspase-2 and Bid were necessary for activation of the canonical inflammasome by infection-associated or general ER stress. These data identify an NLRP3-caspase-2-dependent mechanism that relays ER stress to the mitochondria to promote inflammation, integrating cellular stress and innate immunity. PMID:26341399

  16. Determination of the Action Spectrum of UVR-Induced Mitochondrial DNA Damage in Human Skin Cells.

    PubMed

    Latimer, Jennifer A; Lloyd, James J; Diffey, Brian L; Matts, Paul J; Birch-Machin, Mark A

    2015-10-01

    Biological responses of human skin to UVR including cancer and aging are largely wavelength-dependent, as shown by the action spectra of UVR-induced erythema and nuclear DNA (nDNA) damage. A molecular dosimeter of UVR exposure is therefore required. Although mitochondrial DNA (mtDNA) damage has been shown to be a reliable and sensitive biomarker of UVR exposure in human skin, its wavelength dependency is unknown. The current study solves this problem by determining the action spectrum of UVR-induced mtDNA damage in human skin. Human neonatal dermal fibroblasts and primary human adult keratinocyte cells were irradiated with increasing doses of UVR. Dose-response curves of mtDNA damage were produced for each of the UVR sources and cell types, and an action spectrum for each cell type was determined by mathematical induction. Similarities between these mtDNA damage action spectra and previously determined nDNA damage were observed, with the most detrimental effects occurring over the shorter UVR wavelengths. Notably, a statistically significant (P<0.0001) greater sensitivity to mtDNA damage was observed in dermal fibroblasts compared with keratinocytes at wavelengths >300 nm, possibly indicating a wider picture of depth dependence in sensitivity. This finding has implications for disease/photodamage mechanisms and interventions. PMID:26030182

  17. Nickel(II)-induced nasal epithelial toxicity and oxidative mitochondrial damage.

    PubMed

    Lee, Yoon-Jin; Lim, Soo-Sung; Baek, Byoung Joon; An, Je-Min; Nam, Hae-Seon; Woo, Kee-Min; Cho, Moon-Kyun; Kim, Sung-Ho; Lee, Sang-Han

    2016-03-01

    In probing the underlying mechanisms of nickel(II)-induced cytotoxicity on nasal epithelium, we investigated the effects of nickel(II) acetate on nasal epithelial RPMI-2650 cells. Nickel(II) elicited apoptosis, as signified by pyknotic and fragmented nuclei, increased caspase-3/7 activity, and an increase in annexin V binding, hypodiploid DNA, and Bax/Bcl-2 protein ratio. Nickel(II)-induced G2/M arrest was associated with up-regulation of p21(WAF1/CIP1) expression, decrease in phosphorylation at Thr(161) of Cdc2, and down-regulation of cyclin B1. Associated with these responses, ROS generation and mitochondrial depolarization increased in a nickel(II) concentration-dependent fashion. Pretreatment with N-acetylcysteine (NAC) attenuated these changes. p53 reporter gene assay and analyses of p53, Puma, Bax, and Bcl-2 protein levels indicated that NAC inhibited nickel(II)-induced activation of p53-mediated mitochondrial apoptotic pathway. Collectively, our study provides evidences that nickel(II) may induce oxidative damage on nasal epithelium in which antioxidant NAC protects cells against nickel(II)-induced apoptosis through the prevention of oxidative stress-mediated mitochondrial damage. PMID:26809061

  18. Method for assessing damage to mitochondrial DNA caused by radiation and epichlorohydrin

    SciTech Connect

    Singh, G.; Hauswirth, W.W.; Ross, W.E.; Neims, A.H.

    1985-01-01

    This paper describes a rapid and reliable method for quantification of damage to mitochondrial DNA (mtDNA), especially strand breaks. The degree of damage to mtDNA is assessed by the proportion of physical forms (i.e., supercoiled versus open-circular and linear forms) upon agarose gel electrophoresis, blotting, and visualization by hybridization with (/sup 32/P)mtDNA probes. The use of a radiolabeled probe is a crucial step in the procedure because it provides both a means to quantify by radioautography and to obtain the mtDNA specificity required to eliminate misinterpretation due to nuclear DNA contamination. To demonstrate the utility of this technique, X-irradiation and epichlorohydrin are shown to damage both isolated mtDNA and mtDNA in whole cells in a dose-dependent fashion.

  19. Oxidative stress and mitochondrial damage: importance in non-SOD1 ALS

    PubMed Central

    Carrì, Maria Teresa; Valle, Cristiana; Bozzo, Francesca; Cozzolino, Mauro

    2015-01-01

    It is well known that mitochondrial damage (MD) is both the major contributor to oxidative stress (OS) (the condition arising from unbalance between production and removal of reactive oxygen species) and one of the major consequences of OS, because of the high dependance of mitochondrial function on redox-sensitive targets such as intact membranes. Conditions in which neuronal cells are not able to cope with MD and OS seem to lead or contribute to several neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS), at least in the most studied superoxide dismutase 1 (SOD1)-linked genetic variant. As summarized in this review, new evidence indicates that MD and OS play a role also in non-SOD1 ALS and thus they may represent a target for therapy despite previous failures in clinical trials. PMID:25741238

  20. Oxidative damage of DNA induced by X-irradiation decreases the uterine endometrial receptivity which involves mitochondrial and lysosomal dysfunction

    PubMed Central

    Gao, Wei; Liang, Jin-Xiao; Liu, Shuai; Liu, Chang; Liu, Xiao-Fang; Wang, Xiao-Qi; Yan, Qiu

    2015-01-01

    X irradiation may lead to female infertility and the mechanism is still not clear. After X irradiation exposure, significantly morphological changes and functional decline in endometrial epithelial cells were observed. The mitochondrial and lysosomal dysfunction and oxidative DNA damage were noticed after X irradiation. In addition, pretreatment with NAC, NH4Cl or Pep A reduced the X irradiation induced damages. These studies demonstrate that the oxidative DNA damage which involved dysfunctional lysosomal and mitochondrial contribute to X irradiation-induced impaired receptive state of uterine endometrium and proper protective reagents can be helpful in improving endometrial function. PMID:26064230

  1. MiR-25 protects cardiomyocytes against oxidative damage by targeting the mitochondrial calcium uniporter.

    PubMed

    Pan, Lei; Huang, Bi-Jun; Ma, Xiu-E; Wang, Shi-Yi; Feng, Jing; Lv, Fei; Liu, Yuan; Liu, Yi; Li, Chang-Ming; Liang, Dan-Dan; Li, Jun; Xu, Liang; Chen, Yi-Han

    2015-01-01

    MicroRNAs (miRNAs) are a class of small non-coding RNAs, whose expression levels vary in different cell types and tissues. Emerging evidence indicates that tissue-specific and -enriched miRNAs are closely associated with cellular development and stress responses in their tissues. MiR-25 has been documented to be abundant in cardiomyocytes, but its function in the heart remains unknown. Here, we report that miR-25 can protect cardiomyocytes against oxidative damage by down-regulating mitochondrial calcium uniporter (MCU). MiR-25 was markedly elevated in response to oxidative stimulation in cardiomyocytes. Further overexpression of miR-25 protected cardiomyocytes against oxidative damage by inactivating the mitochondrial apoptosis pathway. MCU was identified as a potential target of miR-25 by bioinformatical analysis. MCU mRNA level was reversely correlated with miR-25 under the exposure of H2O2, and MCU protein level was largely decreased by miR-25 overexpression. The luciferase reporter assay confirmed that miR-25 bound directly to the 3' untranslated region (UTR) of MCU mRNA. MiR-25 significantly decreased H2O2-induced elevation of mitochondrial Ca2+ concentration, which is likely to be the result of decreased activity of MCU. We conclude that miR-25 targets MCU to protect cardiomyocytes against oxidative damages. This finding provides novel insights into the involvement of miRNAs in oxidative stress in cardiomyocytes. PMID:25764156

  2. Differential Effect of Endurance Training on Mitochondrial Protein Damage, Degradation, and Acetylation in the Context of Aging.

    PubMed

    Johnson, Matthew L; Irving, Brian A; Lanza, Ian R; Vendelbo, Mikkel H; Konopka, Adam R; Robinson, Matthew M; Henderson, Gregory C; Klaus, Katherine A; Morse, Dawn M; Heppelmann, Carrie; Bergen, H Robert; Dasari, Surendra; Schimke, Jill M; Jakaitis, Daniel R; Nair, K Sreekumaran

    2015-11-01

    Acute aerobic exercise increases reactive oxygen species and could potentially damage proteins, but exercise training (ET) enhances mitochondrial respiration irrespective of age. Here, we report a differential impact of ET on protein quality in young and older participants. Using mass spectrometry we measured oxidative damage to skeletal muscle proteins before and after 8 weeks of ET and find that young but not older participants reduced oxidative damage to both total skeletal muscle and mitochondrial proteins. Young participants showed higher total and mitochondrial derived semitryptic peptides and 26S proteasome activity indicating increased protein degradation. ET however, increased the activity of the endogenous antioxidants in older participants. ET also increased skeletal muscle content of the mitochondrial deacetylase SIRT3 in both groups. A reduction in the acetylation of isocitrate dehydrogenase 2 was observed following ET that may counteract the effect of acute oxidative stress. In conclusion aging is associated with an inability to improve skeletal muscle and mitochondrial protein quality in response to ET by increasing degradation of damaged proteins. ET does however increase muscle and mitochondrial antioxidant capacity in older individuals, which provides increased buffering from the acute oxidative effects of exercise. PMID:25504576

  3. Enhanced UV-mediated free radical generation; DNA and mitochondrial damage caused by retinol supplementation.

    PubMed

    Klamt, Fábio; Dal-Pizzol, Felipe; Bernard, Elena Aida; Moreira, José Cláudio Fonseca

    2003-08-01

    Retinoid supplementation has been therapeutically used against various human disorders. We and others have demonstrated that retinol treatment causes free radical generation and increased iron uptake, iron storage and oxidative damage, both in vitro and in vivo. Here, we investigate the possible synergistic effect of retinol on UV-mediated free radical generation, oxidative damage to biomolecules and decreased cellular viability in primary cultured mammalian cells. Retinol treatment (7 microM) resulted in a threefold increase in UV-mediated free radical generation and a 40%, increase in lipoperoxidation. DNA fragmentation and mitochondrial oxidative damage also increased significantly in retinol-supplemented UV-irradiated cultured cells as compared to UV-irradiated control cells, which were only treated with the solvent used to deliver the retinol (0.1% ethanol). All measurements were restored to control values when an iron chelator, 1,10-phenanthroline (100 microM), or an OH* scavenger, mannitol (1 mM), was co-administrated. Rather than protecting against free radical generation, retinol seems to enhance UV-mediated oxidative damage and decreases cellular viability in cultured cells. We suggest that retinol-enhanced iron uptake and storage and increased reactive oxygen species generated by the Fenton reaction may act synergistically with UV-irradiation in causing oxidative damage to cells. PMID:14521222

  4. Elimination of damaged mitochondria through mitophagy reduces mitochondrial oxidative stress and increases tolerance to trichothecenes.

    PubMed

    Bin-Umer, Mohamed Anwar; McLaughlin, John E; Butterly, Matthew S; McCormick, Susan; Tumer, Nilgun E

    2014-08-12

    Trichothecene mycotoxins are natural contaminants of small grain cereals and are encountered in the environment, posing a worldwide threat to human and animal health. Their mechanism of toxicity is poorly understood, and little is known about cellular protection mechanisms against trichothecenes. We previously identified inhibition of mitochondrial protein synthesis as a novel mechanism for trichothecene-induced cell death. To identify cellular functions involved in trichothecene resistance, we screened the Saccharomyces cerevisiae deletion library for increased sensitivity to nonlethal concentrations of trichothecin (Tcin) and identified 121 strains exhibiting higher sensitivity than the parental strain. The largest group of sensitive strains had significantly higher reactive oxygen species (ROS) levels relative to the parental strain. A dose-dependent increase in ROS levels was observed in the parental strain treated with different trichothecenes, but not in a petite version of the parental strain or in the presence of a mitochondrial membrane uncoupler, indicating that mitochondria are the main site of ROS production due to toxin exposure. Cytotoxicity of trichothecenes was alleviated after treatment of the parental strain and highly sensitive mutants with antioxidants, suggesting that oxidative stress contributes to trichothecene sensitivity. Cotreatment with rapamycin and trichothecenes reduced ROS levels and cytotoxicity in the parental strain relative to the trichothecene treatment alone, but not in mitophagy deficient mutants, suggesting that elimination of trichothecene-damaged mitochondria by mitophagy improves cell survival. These results reveal that increased mitophagy is a cellular protection mechanism against trichothecene-induced mitochondrial oxidative stress and a potential target for trichothecene resistance. PMID:25071194

  5. Lewy body pathology is associated with mitochondrial DNA damage in Parkinson's disease.

    PubMed

    Müller, Sarina K; Bender, Andreas; Laub, Christoph; Högen, Tobias; Schlaudraff, Falk; Liss, Birgit; Klopstock, Thomas; Elstner, Matthias

    2013-09-01

    Mitochondrial dysfunction has been strongly implicated in the pathogenesis of Parkinson's disease (PD) and Alzheimer's disease (AD), but its relation to protein aggregation is unclear. PD is characterized by synuclein aggregation (i.e., Lewy body [LB] formation). In AD, the abnormal accumulation of tau protein forms neurofibrillary tangles. In this study, we laser-dissected LB-positive and -negative neurons from the substantia nigra of postmortem PD brains, and tau-positive and -negative hippocampal neurons from AD brains. We quantified mitochondrial DNA deletions in relation to the cellular phenotype and in comparison with age-matched controls. Deletion levels were highest in LB-positive neurons of PD brains (40.5 ± 16.8%), followed by LB-negative neurons of PD cases (31.8 ± 14.4%) and control subjects (25.6 ± 17.5%; analysis of variance p < 0.005). In hippocampal neurons, deletion levels were 25%-30%, independent of disease status and neurofibrillary tangles. The presented findings imply increased mitochondrial DNA damage in LB-positive midbrain neurons, but do not support a direct causative link of respiratory chain dysfunction and protein aggregation. PMID:23566333

  6. Modulation of mitochondrial function and autophagy mediates carnosine neuroprotection against ischemic brain damage

    PubMed Central

    Kim, Kyeong-A; Akram, Muhammad; Shin, Young-Jun; Kim, Eun-Sun; Yu, Seong Woon; Majid, Arshad; Bae, Ok-Nam

    2014-01-01

    Background and Purpose Despite the rapidly increasing global burden of ischemic stroke, no therapeutic options for neuroprotection against stroke currently exist. Recent studies have shown that autophagy plays a key role in ischemic neuronal death and treatments that target autophagy may represent a novel strategy in neuroprotection. We investigated whether autophagy is regulated by carnosine, an endogenous pleiotropic dipeptide which has robust neuroprotective activity against ischemic brain damage. Methods We examined the effect of carnosine on mitochondrial dysfunction and autophagic processes in rat focal ischemia and in neuronal cultures. Results Autophagic pathways such as reduction of phosphorylated mTOR/p70S6K and the conversion of LC3-I to LC3-II were enhanced in the ischemic brain. However, treatment with carnosine significantly attenuated autophagic signaling in the ischemic brain, with improvement of brain mitochondrial function and mitophagy signaling. The protective effect of carnosine against autophagy was also confirmed in primary cortical neurons. Conclusion Taken together, our data suggest that the neuroprotective effect of carnosine is at least partially mediated by mitochondrial protection, and attenuation of deleterious autophagic processes. Our findings shed new light on the mechanistic pathways that this exciting neuroprotective agent influences. PMID:24938837

  7. Elimination of damaged mitochondria through mitophagy reduces mitochondrial oxidative stress and increases tolerance to trichothecenes

    PubMed Central

    Bin-Umer, Mohamed Anwar; McLaughlin, John E.; Butterly, Matthew S.; McCormick, Susan; Tumer, Nilgun E.

    2014-01-01

    Trichothecene mycotoxins are natural contaminants of small grain cereals and are encountered in the environment, posing a worldwide threat to human and animal health. Their mechanism of toxicity is poorly understood, and little is known about cellular protection mechanisms against trichothecenes. We previously identified inhibition of mitochondrial protein synthesis as a novel mechanism for trichothecene-induced cell death. To identify cellular functions involved in trichothecene resistance, we screened the Saccharomyces cerevisiae deletion library for increased sensitivity to nonlethal concentrations of trichothecin (Tcin) and identified 121 strains exhibiting higher sensitivity than the parental strain. The largest group of sensitive strains had significantly higher reactive oxygen species (ROS) levels relative to the parental strain. A dose-dependent increase in ROS levels was observed in the parental strain treated with different trichothecenes, but not in a petite version of the parental strain or in the presence of a mitochondrial membrane uncoupler, indicating that mitochondria are the main site of ROS production due to toxin exposure. Cytotoxicity of trichothecenes was alleviated after treatment of the parental strain and highly sensitive mutants with antioxidants, suggesting that oxidative stress contributes to trichothecene sensitivity. Cotreatment with rapamycin and trichothecenes reduced ROS levels and cytotoxicity in the parental strain relative to the trichothecene treatment alone, but not in mitophagy deficient mutants, suggesting that elimination of trichothecene-damaged mitochondria by mitophagy improves cell survival. These results reveal that increased mitophagy is a cellular protection mechanism against trichothecene-induced mitochondrial oxidative stress and a potential target for trichothecene resistance. PMID:25071194

  8. Inhibition of HAS2 induction enhances the radiosensitivity of cancer cells via persistent DNA damage

    SciTech Connect

    Shen, Yan Nan; Shin, Hyun-Jin; Joo, Hyun-Yoo; Park, Eun-Ran; Kim, Su-Hyeon; Hwang, Sang-Gu; Park, Sang Jun; Kim, Chun-Ho; Lee, Kee-Ho

    2014-01-17

    Highlights: •HAS2 may be a promising target for the radiosensitization of human cancer. •HAS2 is elevated (up to ∼10-fold) in irradiated radioresistant and -sensitive cancer cells. •HAS2 knockdown sensitizes cancer cells to radiation. •HAS2 knockdown potentiates irradiation-induced DNA damage and apoptotic death. •Thus, the irradiation-induced up-regulation of HAS2 contributes to the radioresistance of cancer cells. -- Abstract: Hyaluronan synthase 2 (HAS2), a synthetic enzyme for hyaluronan, regulates various aspects of cancer progression, including migration, invasion and angiogenesis. However, the possible association of HAS2 with the response of cancer cells to anticancer radiotherapy, has not yet been elucidated. Here, we show that HAS2 knockdown potentiates irradiation-induced DNA damage and apoptosis in cancer cells. Upon exposure to radiation, all of the tested human cancer cell lines exhibited marked (up to 10-fold) up-regulation of HAS2 within 24 h. Inhibition of HAS2 induction significantly reduced the survival of irradiated radioresistant and -sensitive cells. Interestingly, HAS2 depletion rendered the cells to sustain irradiation-induced DNA damage, thereby leading to an increase of apoptotic death. These findings indicate that HAS2 knockdown sensitizes cancer cells to radiation via persistent DNA damage, further suggesting that the irradiation-induced up-regulation of HAS2 contributes to the radioresistance of cancer cells. Thus, HAS2 could potentially be targeted for therapeutic interventions aimed at radiosensitizing cancer cells.

  9. Cytotoxic activity of tumor necrosis factor is mediated by early damage of mitochondrial functions. Evidence for the involvement of mitochondrial radical generation.

    PubMed

    Schulze-Osthoff, K; Bakker, A C; Vanhaesebroeck, B; Beyaert, R; Jacob, W A; Fiers, W

    1992-03-15

    Structural mitochondrial damage accompanies the cytotoxic effects of several drugs including tumor necrosis factor (TNF). Using various inhibitors of mitochondrial electron transport we have investigated the mechanism of TNF-mediated cytotoxicity in L929 and WEHI 164 clone 13 mouse fibrosarcoma cells. Inhibitors with different sites of action modulated TNF cytotoxicity, however, with contrasting effects on final cell viability. Inhibition of mitochondrial electron transport at complex III (cytochrome c reductase) by antimycin A resulted in a marked potentiation of TNF-mediated injury. In contrast, when the electron flow to ubiquinone was blocked, either at complex I (NADH-ubiquinone oxidoreductase) with amytal or at complex II (succinate-ubiquinone reductase) with thenoyltrifluoroacetone, cells were markedly protected against TNF cytotoxicity. Neither uncouplers nor inhibitors of oxidative phosphorylation nor complex IV (cytochrome c oxidase) inhibitors significantly interfered with TNF-mediated effects, ruling out the involvement of energy-coupled phenomena. In addition, the toxic effects of TNF were counteracted by the addition of antioxidants and iron chelators. Furthermore, we analyzed the direct effect of TNF on mitochondrial morphology and functions. Treatment of L929 cells with TNF led to an early degeneration of the mitochondrial ultrastructure without any pronounced damage of other cellular organelles. Analysis of the mitochondrial electron flow revealed that TNF treatment led to a rapid inhibition of the mitochondria to oxidize succinate and NADH-linked substrates. The inhibition of electron transport was dose-dependent and became readily detectable 60 min after the start of TNF treatment, thus preceding the onset of cell death by at least 3-6 h. In contrast, only minor effects were observed on complex IV activity. The different effects observed with the mitochondrial respiratory chain inhibitors provide suggestive evidence that mitochondrial production

  10. Persistence of DNA damage following exposure of human bladder cells to chronic monomethylarsonous acid

    SciTech Connect

    Wnek, S.M.; Medeiros, M.K.; Eblin, K.E.; Gandolfi, A.J.

    2009-12-01

    Malignant transformation was demonstrated in UROtsa cells following 52-weeks of exposure to 50 nM monomethylarsonous acid (MMA{sup III}); the result was the malignantly transformed cell line, URO-MSC. URO-MSC cells were used to study the induction of DNA damage and the alteration of DNA repair enzymes in both the presence of MMA{sup III} [URO-MSC(+)] and after subsequent removal of MMA{sup III} [URO-MSC(-)] following chronic, low-level exposure. In the presence of MMA{sup III}, URO-MSC(+) cells demonstrated a sustained increase in DNA damage following 12-weeks of exposure; in particular, a significant increase in DNA single-strand breaks at 12-weeks of exposure consistently elevated through 52 weeks. The persistence of DNA damage in URO-MSC cells was assessed after a 2-week removal of MMA{sup III}. URO-MSC(-) cells demonstrated a decrease in DNA damage compared to URO-MSC(+); however, DNA damage in URO-MSC(-) remained significantly elevated when compared to untreated UROtsa and increased in a time-dependent manner. Reactive oxygen species (ROS) were demonstrated to be a critical component in the generation of DNA damage determined through the incubation of ROS scavengers with URO-MSC cells. Poly (ADP-ribose) polymerase (PARP) is a key repair enzyme in DNA single-strand break repair. URO-MSC(+) resulted in a slight increase in PARP activity after 36-weeks of MMA{sup III} exposure, suggesting the presence of MMA{sup III} is inhibiting the increase in PARP activity. In support, PARP activity in URO-MSC(-) increased significantly, coinciding with a subsequent decrease in DNA damage demonstrated in URO-MSC(-) compared to URO-MSC(+). These data demonstrate that chronic, low-level exposure of UROtsa cells to 50 nM MMA{sup III} results in: the induction of DNA damage that remains elevated upon removal of MMA{sup III}; increased levels of ROS that play a role in MMA{sup III} induced-DNA damage; and decreased PARP activity in the presence of MMA{sup III}.

  11. Herpes simplex encephalitis is linked with selective mitochondrial damage; a post-mortem and in vitro study.

    PubMed

    Wnęk, Małgorzata; Ressel, Lorenzo; Ricci, Emanuele; Rodriguez-Martinez, Carmen; Guerrero, Julio Cesar Villalvazo; Ismail, Zarini; Smith, Colin; Kipar, Anja; Sodeik, Beate; Chinnery, Patrick F; Solomon, Tom; Griffiths, Michael J

    2016-09-01

    Herpes simplex virus type-1 (HSV-1) encephalitis (HSE) is the most commonly diagnosed cause of viral encephalitis in western countries. Despite antiviral treatment, HSE remains a devastating disease with high morbidity and mortality. Improved understanding of pathogenesis may lead to more effective therapies. Mitochondrial damage has been reported during HSV infection in vitro. However, whether it occurs in the human brain and whether this contributes to the pathogenesis has not been fully explored. Minocycline, an antibiotic, has been reported to protect mitochondria and limit brain damage. Minocycline has not been studied in HSV infection. In the first genome-wide transcriptomic study of post-mortem human HSE brain tissue, we demonstrated a highly preferential reduction in mitochondrial genome (MtDNA) encoded transcripts in HSE cases (n = 3) compared to controls (n = 5). Brain tissue exhibited a significant inverse correlation for immunostaining between cytochrome c oxidase subunit 1 (CO1), a MtDNA encoded enzyme subunit, and HSV-1; with lower abundance for mitochondrial protein in regions where HSV-1 was abundant. Preferential loss of mitochondrial function, among MtDNA encoded components, was confirmed using an in vitro primary human astrocyte HSV-1 infection model. Dysfunction of cytochrome c oxidase (CO), a mitochondrial enzyme composed predominantly of MtDNA encoded subunits, preceded that of succinate dehydrogenase (composed entirely of nuclear encoded subunits). Minocycline treated astrocytes exhibited higher CO1 transcript abundance, sustained CO activity and cell viability compared to non-treated astrocytes. Based on observations from HSE patient tissue, this study highlights mitochondrial damage as a critical and early event during HSV-1 infection. We demonstrate minocycline preserves mitochondrial function and cell viability during HSV-1 infection. Minocycline, and mitochondrial protection, offers a novel adjunctive therapeutic approach for

  12. Ca2+ toxicity and mitochondrial damage in acute pancreatitis: translational overview

    PubMed Central

    Maléth, József; Hegyi, Péter

    2016-01-01

    Acute pancreatitis (AP) is a leading cause of hospitalization among non-malignant gastrointestinal disorders. The mortality of severe AP can reach 30–50%, which is most probably owing to the lack of specific treatment. Therefore, AP is a major healthcare problem, which urges researchers to identify novel drug targets. Studies from the last decades highlighted that the toxic cellular Ca2+ overload and mitochondrial damage are key pathogenic steps in the disease development affecting both acinar and ductal cell functions. Moreover, recent observations showed that modifying the cellular Ca2+ signalling might be beneficial in AP. The inhibition of Ca2+ release from the endoplasmic reticulum or the activity of plasma membrane Ca2+ influx channels decreased the severity of AP in experimental models. Similarly, inhibition of mitochondrial permeability transition pore (MPTP) opening also seems to improve the outcome of AP in in vivo animal models. At the moment MPTP blockers are under detailed clinical investigation to test whether interventions in MPTP openings and/or Ca2+ homeostasis of the cells can be specific targets in prevention or treatment of cell damage in AP. This article is part of the themed issue ‘Evolution brings Ca2+ and ATP together to control life and death’. PMID:27377719

  13. Synergistic effects of melatonin and deprenyl against MPTP-induced mitochondrial damage and DA depletion.

    PubMed

    Khaldy, Hoda; Escames, Germaine; León, Josefa; Bikjdaouene, Leila; Acuña-Castroviejo, Darío

    2003-01-01

    Previous studies showed a synergistic effect of melatonin and deprenyl against dopamine (DA) autoxidation in vitro. Since oxidative stress is implicated in Parkinson's disease (PD), we explored the effects of melatonin plus deprenyl administration in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in C57/Bl6 mice. Melatonin, but not deprenyl prevents the inhibition of mitochondrial complex I and the oxidative damage in nigrostriatal neurons induced by MPTP. With the dose used deprenyl recovers 50% DA levels and tyrosine hydroxylase activity depressed by the neurotoxin, normalizing locomotor activity of mice. Melatonin, which was unable to counteract MPTP-induced DA depletion and inhibition of tyrosine hydroxylase activity, potentiates the effect of deprenyl on catecholamine turnover and mice ambulatory activity. These results suggest a dissociation of complex I inhibition from DA depletion in this model of Parkinson's disease. The data also support that a combination of melatonin, which improves mitochondrial electron transport chain and reduces oxidative damage, and deprenyl, which promotes the specific function of the rescued neurons, i.e. DA turnover, may be a promising strategy for the treatment of PD. PMID:12600724

  14. Ca2+ toxicity and mitochondrial damage in acute pancreatitis: translational overview.

    PubMed

    Maléth, József; Hegyi, Péter

    2016-08-01

    Acute pancreatitis (AP) is a leading cause of hospitalization among non-malignant gastrointestinal disorders. The mortality of severe AP can reach 30-50%, which is most probably owing to the lack of specific treatment. Therefore, AP is a major healthcare problem, which urges researchers to identify novel drug targets. Studies from the last decades highlighted that the toxic cellular Ca(2+) overload and mitochondrial damage are key pathogenic steps in the disease development affecting both acinar and ductal cell functions. Moreover, recent observations showed that modifying the cellular Ca(2+) signalling might be beneficial in AP. The inhibition of Ca(2+) release from the endoplasmic reticulum or the activity of plasma membrane Ca(2+) influx channels decreased the severity of AP in experimental models. Similarly, inhibition of mitochondrial permeability transition pore (MPTP) opening also seems to improve the outcome of AP in in vivo animal models. At the moment MPTP blockers are under detailed clinical investigation to test whether interventions in MPTP openings and/or Ca(2+) homeostasis of the cells can be specific targets in prevention or treatment of cell damage in AP.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'. PMID:27377719

  15. The novel mitochondrial iron chelator 5-((methylamino)methyl)-8-hydroxyquinoline protects against mitochondrial-induced oxidative damage and neuronal death.

    PubMed

    Mena, Natalia P; García-Beltrán, Olimpo; Lourido, Fernanda; Urrutia, Pamela J; Mena, Raúl; Castro-Castillo, Vicente; Cassels, Bruce K; Núñez, Marco T

    2015-08-01

    Abundant evidence indicates that iron accumulation, oxidative damage and mitochondrial dysfunction are common features of Huntington's disease, Parkinson's disease, Friedreich's ataxia and a group of disorders known as Neurodegeneration with Brain Iron Accumulation. In this study, we evaluated the effectiveness of two novel 8-OH-quinoline-based iron chelators, Q1 and Q4, to decrease mitochondrial iron accumulation and oxidative damage in cellular and animal models of PD. We found that at sub-micromolar concentrations, Q1 selectively decreased the mitochondrial iron pool and was extremely effective in protecting against rotenone-induced oxidative damage and death. Q4, in turn, preferentially chelated the cytoplasmic iron pool and presented a decreased capacity to protect against rotenone-induced oxidative damage and death. Oral administration of Q1 to mice protected substantia nigra pars compacta neurons against oxidative damage and MPTP-induced death. Taken together, our results support the concept that oral administration of Q1 is a promising therapeutic strategy for the treatment of NBIA. PMID:26051278

  16. Quantitative PCR for detection of DNA damage in mitochondrial DNA of the fission yeast Schizosaccharomyces pombe.

    PubMed

    Senoo, Takanori; Yamanaka, Mayumi; Nakamura, Atori; Terashita, Tomoki; Kawano, Shinji; Ikeda, Shogo

    2016-08-01

    Quantitative polymerase chain reaction (QPCR) has been employed to detect DNA damage and repair in mitochondrial DNA (mtDNA) of human and several model organisms. The assay also permits the quantitation of relative mtDNA copy number in cells. Here, we developed the QPCR assay primers and reaction conditions for the fission yeast Schizosaccharomyces pombe, an important model of eukaryote biology, not previously described. Under these conditions, long targets (approximately 10kb) in mtDNA were quantitatively amplified using 0.1ng of crude DNA templates without isolation of mitochondria and mtDNA. Quantitative detection of oxidative DNA damage in mtDNA was illustrated by using a DNA template irradiated with UVA in the presence of riboflavin. The damage to mtDNA in S. pombe cells treated with hydrogen peroxide and paraquat was also quantitatively measured. Finally, we found that mtDNA copy number in S. pombe cells increased after transition into a stationary phase and that the damage to mtDNA due to endogenous cellular processes accumulated during chronological aging. PMID:27236021

  17. Persistent DNA Damage after High Dose In Vivo Gamma Exposure of Minipig Skin

    PubMed Central

    Ahmed, Emad A.; Agay, Diane; Schrock, Gerrit; Drouet, Michel; Meineke, Viktor; Scherthan, Harry

    2012-01-01

    Background Exposure to high doses of ionizing radiation (IR) can lead to localized radiation injury of the skin and exposed cells suffer dsDNA breaks that may elicit cell death or stochastic changes. Little is known about the DNA damage response after high-dose exposure of the skin. Here, we investigate the cellular and DNA damage response in acutely irradiated minipig skin. Methods and Findings IR-induced DNA damage, repair and cellular survival were studied in 15 cm2 of minipig skin exposed in vivo to ∼50 Co-60 γ rays. Skin biopsies of control and 4 h up to 96 days post exposure were investigated for radiation-induced foci (RIF) formation using γ-H2AX, 53BP1, and active ATM-p immunofluorescence. High-dose IR induced massive γ-H2AX phosphorylation and high 53BP1 RIF numbers 4 h, 20 h after IR. As time progressed RIF numbers dropped to a low of <1% of keratinocytes at 28–70 days. The latter contained large RIFs that included ATM-p, indicating the accumulation of complex DNA damage. At 96 days most of the cells with RIFs had disappeared. The frequency of active-caspase-3-positive apoptotic cells was 17-fold increased 3 days after IR and remained >3-fold elevated at all subsequent time points. Replicating basal cells (Ki67+) were reduced 3 days post IR followed by increased proliferation and recovery of epidermal cellularity after 28 days. Conclusions Acute high dose irradiation of minipig epidermis impaired stem cell replication and induced elevated apoptosis from 3 days onward. DNA repair cleared the high numbers of DBSs in skin cells, while RIFs that persisted in <1% cells marked complex and potentially lethal DNA damage up to several weeks after exposure. An elevated frequency of keratinocytes with persistent RIFs may thus serve as indicator of previous acute radiation exposure, which may be useful in the follow up of nuclear or radiological accident scenarios. PMID:22761813

  18. Differential expression and glycative damage affect specific mitochondrial proteins with aging in rat liver.

    PubMed

    Bakala, Hilaire; Ladouce, Romain; Baraibar, Martin A; Friguet, Bertrand

    2013-12-01

    Aging is accompanied by the gradual deterioration of cell functions. Particularly, mitochondrial dysfunction, associated with an accumulation of damaged proteins, is of key importance due to the central role of these organelles in cellular metabolism. However, the detailed molecular mechanisms involved in such impairment have not been completely elucidated. In the present study, proteomic analyses looking at both changes at the expression level as well as to glycative modifications of the mitochondrial proteome were performed. Two-dimensional difference gel electrophoresis analysis revealed 16 differentially expressed proteins with aging. Thirteen exhibited a decreased expression and are crucial enzymes related to OXPHOS chain complex I/V components, TCA cycle or fatty acid β-oxidation reaction. On the other hand, 2 enzymes involved in fatty acid β-oxidation cycle were increased in aged mitochondria. Immunodetection and further identification of glycated proteins disclosed a set of advanced glycation end product-modified proteins, including 6 enzymes involved in the fatty acid β-oxidation process, and 2 enzymes of the TCA/urea cycles. A crucial antioxidant enzyme, catalase, was among the most strongly glycated proteins. In addition, several AGE-damaged enzymes (aldehyde dehydrogenase 2, medium chain acyl-CoA dehydrogenase and 3-ketoacyl-CoA dehydrogenase) exhibited a decreased activity with age. Taken together, these data suggest that liver mitochondria in old rats suffer from a decline in their capacity for energy production, due to (i) decreased expression of OXPHOS complex I/V components and (ii) glycative damage to key fatty acid β-oxidation and TCA/urea cycle enzymes. PMID:23906978

  19. Differences in Liver Injury and Trophoblastic Mitochondrial Damage in Different Preeclampsia-like Mouse Models

    PubMed Central

    Han, Yi-Wei; Yang, Zi; Ding, Xiao-Yan; Yu, Huan

    2015-01-01

    Background: Preeclampsia is a multifactorial disease during pregnancy. Dysregulated lipid metabolism may be related to some preeclampsia. We investigated the relationship between triglycerides (TGs) and liver injury in different preeclampsia-like mouse models and their potential common pathways. Methods: Preeclampsia-like models (Nw-nitro-L-arginine-methyl ester [L-NAME], lipopolysaccharide [LPS], apolipoprotein C-III [Apo] transgnic mice + L-NAME, β2 glycoprotein I [βGPI]) were used in four experimental groups: L-NAME (LN), LPS, Apo-LN and βGPI, respectively, and controls received saline (LN-C, LPS-C, Apo-C, βGPI-C). The first three models were established in preimplantation (PI), early-, mid- and late-gestation (EG, MG and LG). βGPI and controls were injected before implantation. Mean arterial pressure (MAP), 24-hour urine protein, placental and fetal weight, serum TGs, total cholesterol (TC) and pathologic liver and trophocyte changes were assessed. Results: MAP and proteinuria were significantly increased in the experimental groups. Placenta and fetal weight in PI, EP and MP subgroups were significantly lower than LP. Serum TGs significantly increased in most groups but controls. TC was not different between experimental and control groups. Spotty hepatic cell necrosis was observed in PI, EG, MG in LN, Apo-LN and βGPI, but no morphologic changes were observed in the LPS group. Similar trophoblastic mitochondrial damage was observed in every experimental group. Conclusions: Earlier preeclampsia onset causes a higher MAP and urine protein level, and more severe placental and fetal damage. Preeclampsia-like models generated by varied means lead to different changes in lipid metabolism and associated with liver injury. Trophoblastic mitochondrial damage may be the common terminal pathway in different preeclampsia-like models. PMID:26063365

  20. Effect of ambient PM(2.5) on lung mitochondrial damage and fusion/fission gene expression in rats.

    PubMed

    Li, Ruijin; Kou, Xiaojing; Geng, Hong; Xie, Jingfang; Yang, Zhenhua; Zhang, Yuexia; Cai, Zongwei; Dong, Chuan

    2015-03-16

    Exposure to ambient fine particulate matter (PM2.5) increases the risk of respiratory disease. Although previous mitochondrial research has provided new information about PM toxicity in the lung, the exact mechanism of PM2.5-mediated structural and functional damage of lung mitochondria remains unclear. In this study, changes in lung mitochondrial morphology, expression of mitochondrial fission/fusion markers, lipid peroxidation, and transport ATPase activity in SD rats exposed to ambient PM2.5 at different dosages were investigated. Also, the release of reactive oxygen species (ROS) via the respiratory burst in rat alveolar macrophages (AMs) exposed to PM2.5 was examined by luminol-dependent chemiluminescence (CL). The results showed that (1) PM2.5 deposited in the lung and induced pathological damage, particularly causing abnormal alterations of mitochondrial structure, including mitochondrial swelling and cristae disorder or even fragmentation in the presence of higher doses of PM2.5; (2) PM2.5 significantly affected the expression of specific mitochondrial fission/fusion markers (OPA1, Mfn1, Mfn2, Fis1, and Drp1) in rat lung; (3) PM2.5 inhibited Mn superoxide dismutase (MnSOD), Na(+)K(+)-ATPase, and Ca(2+)-ATPase activities and elevated malondialdehyde (MDA) content in rat lung mitochondria; and (4) PM2.5 induced rat AMs to produce ROS, which was inhibited by about 84.1% by diphenyleneiodonium chloride (DPI), an important ROS generation inhibitor. It is suggested that the pathological injury observed in rat lung exposed to PM2.5 is associated with mitochondrial fusion-fission dysfunction, ROS generation, mitochondrial lipid peroxidation, and cellular homeostasis imbalance. Damage to lung mitochondria may be one of the important mechanisms by which PM2.5 induces lung injury, contributing to respiratory diseases. PMID:25560372

  1. Fumarase: a mitochondrial metabolic enzyme and a cytosolic/nuclear component of the DNA damage response.

    PubMed

    Yogev, Ohad; Yogev, Orli; Singer, Esti; Shaulian, Eitan; Goldberg, Michal; Fox, Thomas D; Pines, Ophry

    2010-03-01

    In eukaryotes, fumarase (FH in human) is a well-known tricarboxylic-acid-cycle enzyme in the mitochondrial matrix. However, conserved from yeast to humans is a cytosolic isoenzyme of fumarase whose function in this compartment remains obscure. A few years ago, FH was surprisingly shown to underlie a tumor susceptibility syndrome, Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). A biallelic inactivation of FH has been detected in almost all HLRCC tumors, and therefore FH was suggested to function as a tumor suppressor. Recently it was suggested that FH inhibition leads to elevated intracellular fumarate, which in turn acts as a competitive inhibitor of HPH (HIF prolyl hydroxylase), thereby causing stabilization of HIF (Hypoxia-inducible factor) by preventing proteasomal degradation. The transcription factor HIF increases the expression of angiogenesis regulated genes, such as VEGF, which can lead to high microvessel density and tumorigenesis. Yet this mechanism does not fully explain the large cytosolic population of fumarase molecules. We constructed a yeast strain in which fumarase is localized exclusively to mitochondria. This led to the discovery that the yeast cytosolic fumarase plays a key role in the protection of cells from DNA damage, particularly from DNA double-strand breaks. We show that the cytosolic fumarase is a member of the DNA damage response that is recruited from the cytosol to the nucleus upon DNA damage induction. This function of fumarase depends on its enzymatic activity, and its absence in cells can be complemented by high concentrations of fumaric acid. Our findings suggest that fumarase and fumaric acid are critical elements of the DNA damage response, which underlies the tumor suppressor role of fumarase in human cells and which is most probably HIF independent. This study shows an exciting crosstalk between primary metabolism and the DNA damage response, thereby providing a scenario for metabolic control of tumor propagation

  2. Microwave Processing for Sample Preparation to Evaluate Mitochondrial Ultrastructural Damage in Hemorrhagic Shock

    NASA Astrophysics Data System (ADS)

    Josephsen, Gary D.; Josephsen, Kelly A.; Beilman, Greg J.; Taylor, Jodie H.; Muiler, Kristine E.

    2005-12-01

    This is a report of the adaptation of microwave processing in the preparation of liver biopsies for transmission electron microscopy (TEM) to examine ultrastructural damage of mitochondria in the setting of metabolic stress. Hemorrhagic shock was induced in pigs via 35% total blood volume bleed and a 90-min period of shock followed by resuscitation. Hepatic biopsies were collected before shock and after resuscitation. Following collection, biopsies were processed for TEM by a rapid method involving microwave irradiation (Giberson, 2001). Samples pre- and postshock of each of two animals were viewed and scored using the mitochondrial ultrastructure scoring system (Crouser et al., 2002), a system used to quantify the severity of ultrastructural damage during shock. Results showed evidence of increased ultrastructural damage in the postshock samples, which scored 4.00 and 3.42, versus their preshock controls, which scored 1.18 and 1.27. The results of this analysis were similar to those obtained in another model of shock (Crouser et al., 2002). However, the amount of time used to process the samples was significantly shortened with methods involving microwave irradiation.

  3. Methionine restriction decreases endogenous oxidative molecular damage and increases mitochondrial biogenesis and uncoupling protein 4 in rat brain.

    PubMed

    Naudí, Alba; Caro, Pilar; Jové, Mariona; Gómez, José; Boada, Jordi; Ayala, Victoria; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

    2007-12-01

    Aging plays a central role in the occurrence of neurodegenerative diseases. Caloric restriction (CR) mitigates oxidative stress by decreasing the rate of generation of endogenous damage, a mechanism that can contribute to the slowing of the aging rate induced by this intervention. Various reports have recently linked methionine to aging, and methionine restriction (MetR) without energy restriction also increases life span. We have thus hypothesized that MetR can be responsible, at least in part, for the decrease in endogenous oxidative damage in CR. In this investigation we subjected male rats to exactly the same dietary protocol of MetR that is known to increase their life span. We have found that MetR: (1) decreases the mitochondrial complex I content and activity, as well as complex III content, while the complex II and IV, the mitochondrial flavoprotein apoptosis-inducing factor (AIF) and ATP content are unchanged; (2) increases the mitochondrial biogenesis factor PGC-1alpha; (3) increases the resistance of brain to metabolic and oxidative stress by increasing mitochondrial uncoupling protein 4 uncoupling protein 4 (UCP4); and (4) decreases mitochondrial oxidative DNA damage and all five different markers of protein oxidation measured and lowers membrane unsaturation in rat brain. No changes were detected for protein amino acid composition. These beneficial MetR-induced changes likely derived from metabolic reprogramming at the cellular and tissue level can play a key role in the protection against aging-associated neurodegenerative disorders. PMID:17716000

  4. Analysis of DNA damage and repair in nuclear and mitochondrial DNA of animal cells using quantitative PCR

    PubMed Central

    Furda, Amy M.; Bess, Amanda Smith; Meyer, Joel N.; Van Houten, Bennett

    2015-01-01

    This chapter was written as a guide to using the long-amplicon quantitative PCR (QPCR) assay for the measurement of DNA damage in mammalian as well as non-mammalian species such as C. elegans (nematodes), Drosophila melanogaster (fruit flies) and two species of fish (Fundulus heteroclitus and Danio rerio). Since its development in the early 1990s [1-3], the QPCR assay has been widely used to measure DNA damage and repair kinetics in nuclear and mitochondrial genomes after genotoxin exposure [3-5]. One of the main strengths of the assay is that the labor-intensive and artifact-generating step of mitochondrial isolation is not needed for the accurate measurement of mtDNA copy number and damage. Below we present the advantages and limitations of using QPCR to assay DNA damage in animal cells and provide a detailed protocol of the QPCR assay that integrates its usage in newly developed animal systems. PMID:22941600

  5. Mitochondrial Staining Allows Robust Elimination of Apoptotic and Damaged Cells during Cell Sorting

    PubMed Central

    Ponomarev, Eugeny D.; Tsytsykova, Alla; Armant, Myriam; Vorobjev, Ivan A.

    2014-01-01

    High-speed fluorescence-activated cell sorting is relevant for a plethora of applications, such as PCR-based techniques, microarrays, cloning, and propagation of selected cell populations. We suggest a simple cell-sorting technique to eliminate early and late apoptotic and necrotic cells, with good signal-to-noise ratio and a high-purity yield. The mitochondrial potential dye, TMRE (tetramethylrhodamine ethyl ester perchlorate), was used to separate viable and non-apoptotic cells from the cell sorting samples. TMRE staining is reversible and does not affect cell proliferation and viability. Sorted TMRE+ cells contained a negligible percentage of apoptotic and damaged cells and had a higher proliferative potential as compared with their counterpart cells, sorted on the basis of staining with DNA viability dye. This novel sorting technique using TMRE does not interfere with subsequent functional assays and is a method of choice for the enrichment of functionally active, unbiased cell populations. PMID:24394470

  6. Investigating photoexcitation-induced mitochondrial damage by chemotherapeutic corroles using multimode optical imaging

    NASA Astrophysics Data System (ADS)

    Hwang, Jae Youn; Lubow, David J.; Sims, Jessica D.; Gray, Harry B.; Mahammed, Atif; Gross, Zeev; Medina-Kauwe, Lali K.; Farkas, Daniel L.

    2012-01-01

    We recently reported that a targeted, brightly fluorescent gallium corrole (HerGa) is highly effective for breast tumor detection and treatment. Unlike structurally similar porphryins, HerGa exhibits tumor-targeted toxicity without the need for photoexcitation. We have now examined whether photoexcitation further modulates HerGa toxicity, using multimode optical imaging of live cells, including two-photon excited fluorescence, differential interference contrast (DIC), spectral, and lifetime imaging. Using two-photon excited fluorescence imaging, we observed that light at specific wavelengths augments the HerGa-mediated mitochondrial membrane potential disruption of breast cancer cells in situ. In addition, DIC, spectral, and fluorescence lifetime imaging enabled us to both validate cell damage by HerGa photoexcitation and investigate HerGa internalization, thus allowing optimization of light dose and timing. Our demonstration of HerGa phototoxicity opens the way for development of new methods of cancer intervention using tumor-targeted corroles.

  7. Persistent DNA Damage in Spermatogonial Stem Cells After Fractionated Low-Dose Irradiation of Testicular Tissue

    SciTech Connect

    Grewenig, Angelika; Schuler, Nadine; Rübe, Claudia E.

    2015-08-01

    Purpose: Testicular spermatogenesis is extremely sensitive to radiation-induced damage, and even low scattered doses to testis from radiation therapy may pose reproductive risks with potential treatment-related infertility. Radiation-induced DNA double-strand breaks (DSBs) represent the greatest threat to the genomic integrity of spermatogonial stem cells (SSCs), which are essential to maintain spermatogenesis and prevent reproduction failure. Methods and Materials: During daily low-dose radiation with 100 mGy or 10 mGy, radiation-induced DSBs were monitored in mouse testis by quantifying 53 binding protein 1 (53BP-1) foci in SSCs within their stem cell niche. The accumulation of DSBs was correlated with proliferation, differentiation, and apoptosis of testicular germ cell populations. Results: Even very low doses of ionizing radiation arrested spermatogenesis, primarily by inducing apoptosis in spermatogonia. Eventual recovery of spermatogenesis depended on the survival of SSCs and their functional ability to proliferate and differentiate to provide adequate numbers of differentiating spermatogonia. Importantly, apoptosis-resistant SSCs resulted in increased 53BP-1 foci levels during, and even several months after, fractionated low-dose radiation, suggesting that surviving SSCs have accumulated an increased load of DNA damage. Conclusions: SSCs revealed elevated levels of DSBs for weeks after radiation, and if these DSBs persist through differentiation to spermatozoa, this may have severe consequences for the genomic integrity of the fertilizing sperm.

  8. Mitochondrial reactive oxygen species are scavenged by Cockayne syndrome B protein in human fibroblasts without nuclear DNA damage

    PubMed Central

    Cleaver, James E.; Brennan-Minnella, Angela M.; Swanson, Raymond A.; Fong, Ka-wing; Chen, Junjie; Chou, Kai-ming; Chen, Yih-wen; Revet, Ingrid; Bezrookove, Vladimir

    2014-01-01

    Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role. PMID:25136123

  9. Mitochondrial reactive oxygen species are scavenged by Cockayne syndrome B protein in human fibroblasts without nuclear DNA damage.

    PubMed

    Cleaver, James E; Brennan-Minnella, Angela M; Swanson, Raymond A; Fong, Ka-wing; Chen, Junjie; Chou, Kai-ming; Chen, Yih-wen; Revet, Ingrid; Bezrookove, Vladimir

    2014-09-16

    Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role. PMID:25136123

  10. 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

  11. Mitochondria-targeted Ogg1 and Aconitase-2 Prevent Oxidant-induced Mitochondrial DNA Damage in Alveolar Epithelial Cells*

    PubMed Central

    Kim, Seok-Jo; Cheresh, Paul; Williams, David; Cheng, Yuan; Ridge, Karen; Schumacker, Paul T.; Weitzman, Sigmund; Bohr, Vilhelm A.; Kamp, David W.

    2014-01-01

    Mitochondria-targeted human 8-oxoguanine DNA glycosylase (mt-hOgg1) and aconitase-2 (Aco-2) each reduce oxidant-induced alveolar epithelial cell (AEC) apoptosis, but it is unclear whether protection occurs by preventing AEC mitochondrial DNA (mtDNA) damage. Using quantitative PCR-based measurements of mitochondrial and nuclear DNA damage, mtDNA damage was preferentially noted in AEC after exposure to oxidative stress (e.g. amosite asbestos (5–25 μg/cm2) or H2O2 (100–250 μm)) for 24 h. Overexpression of wild-type mt-hOgg1 or mt-long α/β 317–323 hOgg1 mutant incapable of DNA repair (mt-hOgg1-Mut) each blocked A549 cell oxidant-induced mtDNA damage, mitochondrial p53 translocation, and intrinsic apoptosis as assessed by DNA fragmentation and cleaved caspase-9. In contrast, compared with controls, knockdown of Ogg1 (using Ogg1 shRNA in A549 cells or primary alveolar type 2 cells from ogg1−/− mice) augmented mtDNA lesions and intrinsic apoptosis at base line, and these effects were increased further after exposure to oxidative stress. Notably, overexpression of Aco-2 reduced oxidant-induced mtDNA lesions, mitochondrial p53 translocation, and apoptosis, whereas siRNA for Aco-2 (siAco-2) enhanced mtDNA damage, mitochondrial p53 translocation, and apoptosis. Finally, siAco-2 attenuated the protective effects of mt-hOgg1-Mut but not wild-type mt-hOgg1 against oxidant-induced mtDNA damage and apoptosis. Collectively, these data demonstrate a novel role for mt-hOgg1 and Aco-2 in preserving AEC mtDNA integrity, thereby preventing oxidant-induced mitochondrial dysfunction, p53 mitochondrial translocation, and intrinsic apoptosis. Furthermore, mt-hOgg1 chaperoning of Aco-2 in preventing oxidant-mediated mtDNA damage and apoptosis may afford an innovative target for the molecular events underlying oxidant-induced toxicity. PMID:24429287

  12. Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice.

    PubMed

    Stephenson, Erin J; Ragauskas, Alyse; Jaligama, Sridhar; Redd, JeAnna R; Parvathareddy, Jyothi; Peloquin, Matthew J; Saravia, Jordy; Han, Joan C; Cormier, Stephania A; Bridges, Dave

    2016-06-01

    We have investigated the effects of in utero exposure to environmentally persistent free radicals (EPFRs) on growth, metabolism, energy utilization, and skeletal muscle mitochondria in a mouse model of diet-induced obesity. Pregnant mice were treated with laboratory-generated, combustion-derived particular matter (MCP230). The adult offspring were placed on a high-fat diet for 12 wk, after which we observed a 9.8% increase in their body weight. The increase in body size observed in the MCP230-exposed mice was not associated with increases in food intake but was associated with a reduction in physical activity and lower energy expenditure. The reduced energy expenditure in mice indirectly exposed to MCP230 was associated with reductions in skeletal muscle mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase activity. Upregulation of key genes involved in ameliorating oxidative stress was also observed in the muscle of MCP230-exposed mice. These findings suggest that gestational exposure to MCP230 leads to a reduction in energy expenditure at least in part through alterations to mitochondrial metabolism in the skeletal muscle. PMID:27117006

  13. Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice

    PubMed Central

    Stephenson, Erin J.; Ragauskas, Alyse; Jaligama, Sridhar; Redd, JeAnna R.; Parvathareddy, Jyothi; Peloquin, Matthew J.; Saravia, Jordy; Han, Joan C.; Cormier, Stephania A.

    2016-01-01

    We have investigated the effects of in utero exposure to environmentally persistent free radicals (EPFRs) on growth, metabolism, energy utilization, and skeletal muscle mitochondria in a mouse model of diet-induced obesity. Pregnant mice were treated with laboratory-generated, combustion-derived particular matter (MCP230). The adult offspring were placed on a high-fat diet for 12 wk, after which we observed a 9.8% increase in their body weight. The increase in body size observed in the MCP230-exposed mice was not associated with increases in food intake but was associated with a reduction in physical activity and lower energy expenditure. The reduced energy expenditure in mice indirectly exposed to MCP230 was associated with reductions in skeletal muscle mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase activity. Upregulation of key genes involved in ameliorating oxidative stress was also observed in the muscle of MCP230-exposed mice. These findings suggest that gestational exposure to MCP230 leads to a reduction in energy expenditure at least in part through alterations to mitochondrial metabolism in the skeletal muscle. PMID:27117006

  14. Selenite induces DNA damage and specific mitochondrial degeneration in human bladder cancer cells.

    PubMed

    Řezáčová, K; Čáňová, K; Bezrouk, A; Rudolf, E

    2016-04-01

    We have investigated the cytotoxicity and specific effects of selenite in human bladder cancer cell line RT-112 and its clonogenic variant RT-112 HB. Selenite inhibited cell growth and proliferation in both cell lines. Treated cells developed extensive vacuolization which was dose independent but occurring in differing time frames. Ultrastructure analysis revealed that the observed vacuoles are damaged mitochondria and potentially other subcellular compartments. Selenite-specific effects on mitochondria were further confirmed by mitochondrial membrane potential analysis, changes in ATP production and generation of superoxide. Simultaneously, selenite induced DNA damage in treated cells with activation of p53, PARP-1 and JNK and suppressed autophagy. Cells ultimately died via a combination of apoptosis, necrosis and a distinct type of cell death featuring "vacuolar shrinkage", loss of adherence and absence of secondary necrosis as well as other classical markers of either apoptosis or autophagy. The significant presence of so called necroptosis was also not confirmed as the specific inhibitor necrostatin-1 could not prevent cell death. These results thus confirm the toxicity of selenite in bladder cancer cells while pointing at potentially new mechanism of action of this compound in this model. PMID:26718266

  15. Vitamin E protects against the mitochondrial damage caused by cyclosporin A in LLC-PK1 cells

    SciTech Connect

    Arriba, G. de Perez de Hornedo, J.; Ramirez Rubio, S.; Calvino Fernandez, M.; Benito Martinez, S.; Maiques Camarero, M.; Parra Cid, T.

    2009-09-15

    Cyclosporin A (CsA) has nephrotoxic effects known to involve reactive oxygen species (ROS), since antioxidants prevent the kidney damage induced by this drug. Given that mitochondria are among the main sources of intracellular ROS, the aims of our study were to examine the mitochondrial effects of CsA in the porcine renal endothelial cell line LLC-PK1 and the influence of the antioxidant Vitamin E (Vit E). Following the treatment of LLC-PK1 cells with CsA, we assessed the mitochondrial synthesis of superoxide anion, permeability transition pore opening, mitochondrial membrane potential, cardiolipin peroxidation, cytochrome c release and cellular apoptosis, using flow cytometry and confocal microscopy procedures. Similar experiments were done after Vit E preincubation of cells. CsA treatment increased superoxide anion in a dose-dependent way. CsA opened the permeability transition pores, caused Bax migration to mitochondria, and decreased mitochondrial membrane potential and cardiolipin content. Also CsA released cytochrome c into cytosol and provoked cellular apoptosis. Vit E pretreatment inhibited the effects that CsA induced on mitochondrial structure and function in LLC-PK1 cells and avoided apoptosis. CsA modifies mitochondrial LLC-PK1 cell physiology with loss of negative electrochemical gradient across the inner mitochondrial membrane and increased lipid peroxidation. These features are related to apoptosis and can explain the cellular damage that CsA induces. As Vit E inhibited these effects, our results suggest that they were mediated by an increase in ROS production by mitochondria.

  16. Mutations of the Thyroid Hormone Transporter MCT8 Cause Prenatal Brain Damage and Persistent Hypomyelination

    PubMed Central

    López-Espíndola, Daniela; Morales-Bastos, Carmen; Grijota-Martínez, Carmen; Liao, Xiao-Hui; Lev, Dorit; Sugo, Ella; Verge, Charles F.; Refetoff, Samuel

    2014-01-01

    Context: Mutations in the MCT8 (SLC16A2) gene, encoding a specific thyroid hormone transporter, cause an X-linked disease with profound psychomotor retardation, neurological impairment, and abnormal serum thyroid hormone levels. The nature of the central nervous system damage is unknown. Objective: The objective of the study was to define the neuropathology of the syndrome by analyzing brain tissue sections from MCT8-deficient subjects. Design: We analyzed brain sections from a 30th gestational week male fetus and an 11-year-old boy and as controls, brain tissue from a 30th and 28th gestational week male and female fetuses, respectively, and a 10-year-old girl and a 12-year-old boy. Methods: Staining with hematoxylin-eosin and immunostaining for myelin basic protein, 70-kDa neurofilament, parvalbumin, calbindin-D28k, and synaptophysin were performed. Thyroid hormone determinations and quantitative PCR for deiodinases were also performed. Results: The MCT8-deficient fetus showed a delay in cortical and cerebellar development and myelination, loss of parvalbumin expression, abnormal calbindin-D28k content, impaired axonal maturation, and diminished biochemical differentiation of Purkinje cells. The 11-year-old boy showed altered cerebellar structure, deficient myelination, deficient synaptophysin and parvalbumin expression, and abnormal calbindin-D28k expression. The MCT8-deficient fetal cerebral cortex showed 50% reduction of thyroid hormones and increased type 2 deiodinase and decreased type 3 deiodinase mRNAs. Conclusions: The following conclusions were reached: 1) brain damage in MCT8 deficiency is diffuse, without evidence of focal lesions, and present from fetal stages despite apparent normality at birth; 2) deficient hypomyelination persists up to 11 years of age; and 3) the findings are compatible with the deficient action of thyroid hormones in the developing brain caused by impaired transport to the target neural cells. PMID:25222753

  17. Persistence of Space Radiation Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts

    NASA Technical Reports Server (NTRS)

    George, Kerry; Cucinotta, Francis A.

    2008-01-01

    Cytogenetic damage in astronaut's peripheral blood lymphocytes is a useful in vivo marker of space radiation induced damage. Moreover, if radiation induced chromosome translocations persist in peripheral blood lymphocytes for many years, as has been assumed, they could potentially be used to measure retrospective doses or prolonged low dose rate exposures. However, as more data becomes available, evidence suggests that the yield of translocations may decline with time after exposure, at least in the case of space radiation exposures. We present our latest follow-up measurements of chromosome aberrations in astronauts blood lymphocytes assessed by FISH painting and collected a various times beginning directly after return from space to several years after flight. For most individuals the analysis of individual time-courses for translocations revealed a temporal decline of yields with different half-lives. Since the level of stable aberrations depends on the interplay between natural loss of circulating T-lymphocytes and replenishment from the stem or progenitor cells, the differences in the rates of decay could be explained by inter-individual variation in lymphocyte turn over. Biodosimetry estimates derived from cytogenetic analysis of samples collected a few days after return to earth lie within the range expected from physical dosimetry. However, a temporal decline in yields may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure. In addition, limited data on multiple flights show a lack of correlation between time in space and translocation yields. Data from one crewmember who has participated in two separate long-duration space missions and has been followed up for over 10 years provides limited information on the effect of repeat flights and show a possible adaptive response to space radiation exposure.

  18. Influence of heavy ions on cell survival, cytogenetic damage and mitochondrial function of human endothelial cells

    NASA Astrophysics Data System (ADS)

    Ritter, Sylvia; Helm, Alexander; Lee, Ryonfa; Pollet, Dieter; Durante, Marco

    There is increasing evidence that there is an elevated risk of cardiovascular disease among atomic bomb survivors and radiotherapy patients, typically developing with a long latency. However, essentially no information is available on the potential cardiovascular risks associated with space radiation, in particular heavy ions. To address this issue, we have chosen human umbilical vein endothelial cells (HUVEC) as a model system. Cells at an early passage number were irradiated with 0.1 to 4 Gy of either 9.8 MeV/u C-ions (LET=170 keV/µm), 91 MeV/u C-ions (LET=29 keV/µm) or 250 kV X-rays. Cells were regularly subcultured up to 40 days (20 population doublings) post-irradiation. Immediately after exposure cell inactivation was deter-mined by the colony forming assay. Furthermore, at selected time-points cytogenetic damage (formation of micronuclei in binucleated cells) and the mitochondrial membrane potential ΨM (flow cytometric analysis following JC-1 staining) were assessed. Measurement of the directly induced radiation damage showed that 9.8 MeV/u and 91 MeV/u C-ions were more effective than X-rays (i.e. about 3 and 2 times, respectively) with respect to cell inactivation or the in-duction of cytogenetic damage. At the subsequent days in the irradiated cultures the number of cells with micronuclei declined to the control level (3-5Altogether our data indicate that under the applied radiation conditions the integrity of mitochondria which play a significant role in the regulation of cardiovascular cell function is not impaired. With respect to directly induced genetic damage C-ions are more effective than X-rays as observed in other cell systems. If the effectiveness of charged particles for the occurrence of late chromosomal damage in endothelial cells is higher than that of sparsely ionizing radiation needs further clarification. The data obtained up to now indicate that sophisticated cytogenetic techniques have to be applied in order to draw any firm

  19. HMGB1 facilitates repair of mitochondrial DNA damage and extends the lifespan of mutant ataxin-1 knock-in mice

    PubMed Central

    Ito, Hikaru; Fujita, Kyota; Tagawa, Kazuhiko; Chen, Xigui; Homma, Hidenori; Sasabe, Toshikazu; Shimizu, Jun; Shimizu, Shigeomi; Tamura, Takuya; Muramatsu, Shin-ichi; Okazawa, Hitoshi

    2015-01-01

    Mutant ataxin-1 (Atxn1), which causes spinocerebellar ataxia type 1 (SCA1), binds to and impairs the function of high-mobility group box 1 (HMGB1), a crucial nuclear protein that regulates DNA architectural changes essential for DNA damage repair and transcription. In this study, we established that transgenic or virus vector-mediated complementation with HMGB1 ameliorates motor dysfunction and prolongs lifespan in mutant Atxn1 knock-in (Atxn1-KI) mice. We identified mitochondrial DNA damage repair by HMGB1 as a novel molecular basis for this effect, in addition to the mechanisms already associated with HMGB1 function, such as nuclear DNA damage repair and nuclear transcription. The dysfunction and the improvement of mitochondrial DNA damage repair functions are tightly associated with the exacerbation and rescue, respectively, of symptoms, supporting the involvement of mitochondrial DNA quality control by HMGB1 in SCA1 pathology. Moreover, we show that the rescue of Purkinje cell dendrites and dendritic spines by HMGB1 could be downstream effects. Although extracellular HMGB1 triggers inflammation mediated by Toll-like receptor and receptor for advanced glycation end products, upregulation of intracellular HMGB1 does not induce such side effects. Thus, viral delivery of HMGB1 is a candidate approach by which to modify the disease progression of SCA1 even after the onset. PMID:25510912

  20. Extensive and evolutionarily persistent mitochondrial tRNA editing in Velvet Worms (phylum Onychophora).

    PubMed

    Segovia, Romulo; Pett, Walker; Trewick, Steve; Lavrov, Dennis V

    2011-10-01

    Mitochondrial genomes of onychophorans (velvet worms) present an interesting problem: Some previous studies reported them lacking several transfer RNA (tRNA) genes, whereas others found that all their tRNA genes were present but severely reduced. To resolve this discrepancy, we determined complete mitochondrial DNA (mtDNA) sequences of the onychophorans Oroperipatus sp. and Peripatoides sympatrica as well as cDNA sequences from 14 and 10 of their tRNAs, respectively. We show that tRNA genes in these genomes are indeed highly reduced and encode truncated molecules, which are restored to more conventional structures by extensive tRNA editing. During this editing process, up to 34 nucleotides are added to the tRNA sequences encoded in Oroperipatus sp. mtDNA, rebuilding the aminoacyl acceptor stem, the TΨC arm, and in some extreme cases, the variable arm and even a part of the anticodon stem. The editing is less extreme in P. sympatrica in which at least a part of the TΨC arm is always encoded in mtDNA. When the entire TΨC arm is added de novo in Oroperipatus sp., the sequence of this arm is either identical or similar among different tRNA species, yet the sequences show substantial variation for each tRNA. These observations suggest that the arm is rebuilt, at least in part, by a template-independent mechanism and argue against the alternative possibility that tRNA genes or their parts are imported from the nucleus. By contrast, the 3' end of the aminoacyl acceptor stem is likely restored by a template-dependent mechanism. The extreme tRNA editing reported here has been preserved for >140 My as it was found in both extant families of onychophorans. Furthermore, a similar type of tRNA editing may be present in several other groups of arthropods, which show a high degree of tRNA gene reduction in their mtDNA. PMID:21546355

  1. Mitochondrial protein-derived cryptides: Are endogenous N-formylated peptides including mitocryptide-2 components of mitochondrial damage-associated molecular patterns?

    PubMed

    Marutani, Takayuki; Hattori, Tatsuya; Tsutsumi, Koki; Koike, Yusuke; Harada, Akihiko; Noguchi, Kosuke; Kiso, Yoshiaki; Mukai, Hidehito

    2016-11-01

    Recently, much attention has been paid to "nonclassical" bioactive peptides, which are fragmented peptides simultaneously produced during maturation and degradation of various functional proteins. We identified many fragmented peptides derived from various mitochondrial proteins including mitocryptide-1 and mitocryptide-2 that efficiently activate neutrophils. These endogenous, functionally active, fragmented peptides are referred to as "cryptides." Among them, mitocryptide-2 is an N-formylated cryptide cleaved from mitochondrial cytochrome b that is encoded in mitochondrial DNA (mtDNA). It is known that 13 proteins encoded in mtDNA are translated in mitochondria as N-formylated forms, suggesting the existence of endogenous N-formylated peptides other than mitocryptide-2. Here, we investigated the effects of N-formylated peptides presumably cleaved from mtDNA-encoded proteins other than cytochrome b on the functions of neutrophilic cells to elucidate possible regulation by endogenous N-formylated cryptides. Four N-formylated cryptides derived from cytochrome c oxidase subunit I and NADH dehydrogenase subunits 4, 5, and 6 among 12 peptides from mtDNA-encoded proteins efficiently induced not only migration but also β-hexosaminidase release, which is an indicator of neutrophilic phagocytosis, in HL-60 cells differentiated into neutrophilic cells. These activities were comparable to or higher than those induced by mitocryptide-2. Although endogenous N-formylated peptides that are contained in mitochondrial damage-associated molecular patterns (DAMPs) have yet to be molecularly identified, they have been implicated in innate immunity. Thus, N-formylated cryptides including mitocryptide-2 are first-line candidates for the contents of mitochondrial DAMPs to promote innate immune responses. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 580-587, 2016. PMID:26600263

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

    SciTech Connect

    Cheshchevik, V.T.; Lapshina, E.A.; Dremza, I.K.; Zabrodskaya, S.V.; Reiter, R.J.; Prokopchik, N.I.; Zavodnik, I.B.

    2012-06-15

    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%, p < 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

  3. Excitotoxic Insult Results in a Long-Lasting Activation of CaMKIIα and Mitochondrial Damage in Living Hippocampal Neurons

    PubMed Central

    Otmakhov, Nikolai; Gorbacheva, Elena V.; Regmi, Shaurav; Yasuda, Ryohei; Hudmon, Andy; Lisman, John

    2015-01-01

    Over-activation of excitatory NMDA receptors and the resulting Ca2+ overload is the main cause of neuronal toxicity during stroke. CaMKII becomes misregulated during such events. Biochemical studies show either a dramatic loss of CaMKII activity or its persistent autonomous activation after stroke, with both of these processes being implicated in cell toxicity. To complement the biochemical data, we monitored CaMKII activation in living hippocampal neurons in slice cultures using high spatial/temporal resolution two-photon imaging of the CaMKIIα FRET sensor, Camui. CaMKII activation state was estimated by measuring Camui fluorescence lifetime. Short NMDA insult resulted in Camui activation followed by a redistribution of its protein localization: an increase in spines, a decrease in dendritic shafts, and concentration into numerous clusters in the cell soma. Camui activation was either persistent (> 1–3 hours) or transient (~20 min) and, in general, correlated with its protein redistribution. After longer NMDA insult, however, Camui redistribution persisted longer than its activation, suggesting distinct regulation/phases of these processes. Mutational and pharmacological analysis suggested that persistent Camui activation was due to prolonged Ca2+ elevation, with little impact of autonomous states produced by T286 autophosphorylation and/or by C280/M281 oxidation. Cell injury was monitored using expressible mitochondrial marker mito-dsRed. Shortly after Camui activation and clustering, NMDA treatment resulted in mitochondrial swelling, with persistence of the swelling temporarily linked to the persistence of Camui activation. The results suggest that in living neurons excitotoxic insult produces long-lasting Ca2+-dependent active state of CaMKII temporarily linked to cell injury. CaMKII function, however, is to be restricted due to strong clustering. The study provides the first characterization of CaMKII activation dynamics in living neurons during excitotoxic

  4. Mitochondrial DNA oxidative damage contributes to cardiomyocyte ischemia/reperfusion-injury in rats: cardioprotective role of lycopene.

    PubMed

    Yue, Rongchuan; Xia, Xuewei; Jiang, Jiahui; Yang, Dezhong; Han, Yu; Chen, Xiongwen; Cai, Yue; Li, Liangpeng; Wang, Wei Eric; Zeng, Chunyu

    2015-09-01

    Mitochondrial (mt) dysfunction and oxidative stress are involved in the pathogenesis of ischemia/reperfusion (I/R)-injury. Lycopene, a lipophilic antioxidant found mainly in tomatoes and in other vegetables and fruits, can protect mtDNA against oxidative damage. However, the role of mtDNA in myocardial I/R-injury is unclear. In the present study, we aimed to determine if and how lycopene protects cardiomyocytes from I/R-injury. In both in vitro and in vivo studies, I/R-injury increased mt 8-hydroxyguanine (8-OHdG) content, decreased mtDNA content and mtDNA transcription levels, and caused mitochondrial dysfunction in cardiomyocytes. These effects of I/R injury on cardiomycoytes were blocked by pre-treatment with lycopene. MtDNA depletion alone was sufficient to induce cardiomyocyte death. I/R-injury decreased the protein level of a key activator of mt transcription, mitochondrial transcription factor A (Tfam), which was blocked by lycopene. The protective effect of lycopene on mtDNA was associated with a reduction in mitochondrial ROS production and stabilization of Tfam. In conclusion, lycopene protects cardiomyocytes from the oxidative damage of mtDNA induced by I/R-injury. PMID:25656550

  5. Protective Effects of Salidroside on Mitochondrial Functions against Exertional Heat Stroke-Induced Organ Damage in the Rat

    PubMed Central

    Zhang, Wei; Peng, Ming; Yang, Yang; Xiao, Zhangwu; Song, Bin; Lin, Zhaofen

    2015-01-01

    Exertional heat stroke (EHS) results in a constellation of systemic inflammatory responses resulting in multiorgan failure and an extremely high mortality. The present study was designed to evaluate the protective effects of salidroside on EHS by improving mitochondrial functions in the rat model. Liver and heart mitochondria were observed by transmission electron microscopy and mitochondrial membrane potential (ΔΨm) was detected by a fluorescent probe. Intramitochondrial free Ca2+ concentration, mitochondrial respiratory control ratio (RCR), reactive oxygen species (ROS) levels, superoxide dismutase (SOD), and malondialdehyde (MDA) activity were detected by the corresponding kits. RT-PCR was performed to estimate peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and manganese form of SOD (MnSOD) mRNA expression. The results demonstrated that salidroside was able to relieve EHS damage by reducing the swelling of mitochondria, ROS levels, and MDA activity, as well as increasing ΔΨm, RCR, free Ca2+ concentration, SOD, PGC-1α, and MnSOD mRNA levels. In conclusion, salidroside has protective effects on mitochondrial functions against exertional heat stroke-induced organ damage in the rat. PMID:26664452

  6. Mitochondrial anti-oxidant protects IEX-1 deficient mice from organ damage during endotoxemia.

    PubMed

    Ramsey, Haley; Wu, Mei X

    2014-12-01

    Sepsis, a leading cause of mortality in intensive care units worldwide, is often a result of overactive and systemic inflammation following serious infections. We found that mice lacking immediate early responsive gene X-1 (IEX-1) were prone to lipopolysaccharide (LPS) -induced endotoxemia. A nonlethal dose of LPS provoked numerous aberrations in IEX-1 knockout (KO) mice including pancytopenia, increased serum aspartate aminotransferase (AST), and lung neutrophilia, concurrent with liver and kidney damage, followed by death. Given these results, in conjunction with a proven role for IEX-1 in the regulation of reactive oxygen species (ROS) homeostasis during stress, we pre-treated IEX-1 KO mice with Mitoquinone (MitoQ), a mitochondrion-based antioxidant prior to LPS injection. The treatment significantly reduced ROS formation in circulatory cells and protected against pancytopenia and multiple organ failure, drastically increasing the survival rate of IEX-1 KO mice challenged by this low dose of LPS. This study confirms significant contribution of mitochondrial ROS to the etiology of sepsis. PMID:25466275

  7. Age-related alterations in oxidatively damaged proteins of mouse skeletal muscle mitochondrial electron transport chain complexes

    PubMed Central

    Choksi, Kashyap B.; Nuss, Jonathan E.; DeFord, James H.; Papaconstantinou, John

    2010-01-01

    Age-associated mitochondrial dysfunction is a major source of reactive oxygen species (ROS) and oxidative modification to proteins. Mitochondrial electron transport chain (ETC) complexes I and III are the sites of ROS production and we hypothesize that proteins of the ETC complexes are primary targets of ROS-mediated modification which impairs their structure and function. The pectoralis, primarily an aerobic red muscle, and quadriceps, primarily an anaerobic white muscle, have different rates of respiration and oxygen-carrying capacity, and hence, different rates of ROS production. This raises the question of whether these muscles exhibit different levels of oxidative protein modification. Our studies reveal that the pectoralis shows a dramatic age-related decline in almost all complex activities that correlates with increased oxidative modification. Similar complex proteins were modified in the quadriceps, at a significantly lower level with less change in enzyme and ETC coupling function. We postulate that mitochondrial ROS causes damage to specific ETC subunits which increases with age and leads to further mitochondrial dysfunction. We conclude that physiological characteristics of the pectoralis vs quadriceps may play a role in age-associated rate of mitochondrial dysfunction and in the decline in tissue function. PMID:18598756

  8. Supplementation of T3 Recovers Hypothyroid Rat Liver Cells from Oxidatively Damaged Inner Mitochondrial Membrane Leading to Apoptosis

    PubMed Central

    Mukherjee, Sutapa; Samanta, Luna; Roy, Anita; Bhanja, Shravani; Chainy, Gagan B. N.

    2014-01-01

    Hypothyroidism is a growing medical concern. There are conflicting reports regarding the mechanism of oxidative stress in hypothyroidism. Mitochondrial oxidative stress is pivotal to thyroid dysfunction. The present study aimed to delineate the effects of hepatic inner mitochondrial membrane dysfunction as a consequence of 6-n-propyl-2-thiouracil-induced hypothyroidism in rats. Increased oxidative stress predominance in the submitochondrial particles (SMP) and altered antioxidant defenses in the mitochondrial matrix fraction correlated with hepatocyte apoptosis. In order to check whether the effects caused by hypothyroidism are reversed by T3, the above parameters were evaluated in a subset of T3-treated hypothyroid rats. Complex I activity was inhibited in hypothyroid SMP, whereas T3 supplementation upregulated electron transport chain complexes. Higher mitochondrial H2O2 levels in hypothyroidism due to reduced matrix GPx activity culminated in severe oxidative damage to membrane lipids. SMP and matrix proteins were stabilised in hypothyroidism but exhibited increased carbonylation after T3 administration. Glutathione content was higher in both. Hepatocyte apoptosis was evident in hypothyroid liver sections; T3 administration, on the other hand, exerted antiapoptotic and proproliferative effects. Hence, thyroid hormone level critically regulates functional integrity of hepatic mitochondria; hypothyroidism injures mitochondrial membrane lipids leading to hepatocyte apoptosis, which is substantially recovered upon T3 supplementation. PMID:24987693

  9. O(2) uptake in the light in chlamydomonas: evidence for persistent mitochondrial respiration.

    PubMed

    Peltier, G; Thibault, P

    1985-09-01

    The nature of the process responsible for the stationary O(2) uptake occurring in the light under saturating CO(2) concentration in Chlamydomonas reinhardii has been investigated. For this purpose, a mass spectrometer with a membrane inlet system was used to measure O(2) uptake and evolution in the algal suspension. First, we observed that the O(2) uptake rate was constant (about 0.5 micromoles of O(2) per milligram chlorophyll per minute) during a light to dark transition and was not affected by 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Salicylhydroxamic acid had no effect on O(2) uptake in the dark or in the light, but was found to have the same inhibitory effect either in the dark or in the light when added to cyanide-treated algae. The stimulation of the O(2) uptake rate due to the uncoupling effect of carbonyl cyanide m-chlorophenylhydrazone was about the same in the dark or in the light. From these results, we conclude that mitochondrial respiration is maintained during illumination and therefore is not inhibited by high ATP levels. Another conclusion is that in conditions where photorespiration is absent, no other light-dependent O(2) uptake process occurs. If Mehler reactions are involved, in Chlamydomonas, under conditions where both photosynthetic carbon oxidation and reduction cycles cannot operate (as in cyanide-treated algae), their occurrence in photosynthesizing algae either under saturating CO(2) concentration or at the CO(2) compensation point appears very unlikely. The comparison with the situation previously reported in Scenedesmus (R. J. Radmer and B. Kok 1976 Plant Physiol 58: 336-340) suggests that different O(2) uptake processes might be present in these two algal species. PMID:16664375

  10. DAF-16/FoxO and EGL-27/GATA promote developmental growth in response to persistent somatic DNA damage

    PubMed Central

    Babu, Vipin; Ermolaeva, Maria A.; Müller, Roman-Ulrich; Frommolt, Peter; Williams, Ashley B.; Greiss, Sebastian; Schneider, Jennifer I.; Benzing, Thomas; Schermer, Bernhard; Schumacher, Björn

    2014-01-01

    Genome maintenance defects cause complex disease phenotypes characterized by developmental failure, cancer susceptibility, and premature aging. It remains poorly understood how DNA damage responses function during organismal development and maintain tissue functionality when DNA damage accumulates with aging. Here we show that the FoxO transcription factor DAF-16 is activated in response to DNA damage during development while the DNA damage responsiveness of DAF-16 declines with aging. We find that in contrast to its established role in mediating starvation arrest, DAF-16 alleviates DNA damage-induced developmental arrest and even in the absence of DNA repair promotes developmental growth and enhances somatic tissue functionality. We demonstrate that the GATA transcription factor EGL-27 co-regulates DAF-16 target genes in response to DNA damage and together with DAF-16 promotes developmental growth. We propose that EGL-27/GATA activity specifies DAF-16 mediated DNA damage responses to enable developmental progression and to prolong tissue functioning when DNA damage persists. PMID:25419847

  11. Parallel damage in mitochondrial and lysosomal compartments promotes efficient cell death with autophagy: The case of the pentacyclic triterpenoids

    PubMed Central

    Martins, Waleska K.; Costa, Érico T.; Cruz, Mário C.; Stolf, Beatriz S.; Miotto, Ronei; Cordeiro, Rodrigo M.; Baptista, Maurício S.

    2015-01-01

    The role of autophagy in cell death is still controversial and a lot of debate has concerned the transition from its pro-survival to its pro-death roles. The similar structure of the triterpenoids Betulinic (BA) and Oleanolic (OA) acids allowed us to prove that this transition involves parallel damage in mitochondria and lysosome. After treating immortalized human skin keratinocytes (HaCaT) with either BA or OA, we evaluated cell viability, proliferation and mechanism of cell death, function and morphology of mitochondria and lysosomes, and the status of the autophagy flux. We also quantified the interactions of BA and OA with membrane mimics, both in-vitro and in-silico. Essentially, OA caused mitochondrial damage that relied on autophagy to rescue cellular homeostasis, which failed upon lysosomal inhibition by Chloroquine or Bafilomycin-A1. BA caused parallel damage on mitochondria and lysosome, turning autophagy into a destructive process. The higher cytotoxicity of BA correlated with its stronger efficiency in damaging membrane mimics. Based on these findings, we underlined the concept that autophagy will turn into a destructive outcome when there is parallel damage in mitochondrial and lysosomal membranes. We trust that this concept will help the development of new drugs against aggressive cancers. PMID:26213355

  12. Deficiency in Cardiolipin Reduces Doxorubicin-Induced Oxidative Stress and Mitochondrial Damage in Human B-Lymphocytes

    PubMed Central

    Aryal, Baikuntha; Rao, V. Ashutosh

    2016-01-01

    Cardiolipin (CL) is an inner mitochondrial membrane phospholipid which plays an important role in mitochondrial function. Perturbation in CL biosynthesis alters mitochondrial bioenergetics causing a severe genetic disorder commonly known as Barth syndrome. Barth syndrome patients are known to have a reduced concentration and altered composition of CL. Cardiolipin is also known to have a high affinity for the chemotherapeutic agent doxorubicin (Dox), resulting in an extensive mitochondrial accumulation of the drug. Our results indicate that B-lymphocytes from healthy individuals are more sensitive to Dox-induced oxidative stress and cellular toxicity compared to the B-lymphocytes from Barth syndrome as indicated by greater cell death and greater level of cleaved caspase-3 following Dox treatment. Barth lymphocytes, when compared to healthy lymphocytes, showed a greater basal level of mitochondrial reactive oxygen species (mito-ROS), yet exhibited a lower level of induced mito-ROS production in response to Dox. Significantly less ATP content and slightly greater OXPHOS protein levels were detected in healthy cells compared to Barth cells after Dox treatment. Consistent with greater mitochondrial ROS, treatment with Dox induced a higher level of lipid peroxidation and protein carbonylation in healthy lymphocytes compared to Barth lymphocytes. The final remodeling of CL during CL synthesis is catalyzed by the tafazzin protein. Knockdown of tafazzin gene in H9c2 cardiomyocytes using siRNA showed decreased oxidant-induced damage, as observed in Barth lymphocytes. Our findings demonstrate that a deficiency in CL might provide a therapeutic advantage in favor of oxidant-induced anticancer activities. PMID:27434059

  13. Protective effect of boldine on oxidative mitochondrial damage in streptozotocin-induced diabetic rats.

    PubMed

    Jang, Y Y; Song, J H; Shin, Y K; Han, E S; Lee, C S

    2000-10-01

    Increased oxidative stress has been suggested to be involved in the pathogenesis and progression of diabetic tissue damage. Several antioxidants have been described as beneficial for oxidative stress-associated diseases. Boldine ([s]-2,9-dihydroxy-1, 10-dimethoxyaporphine) is a major alkaloid found in the leaves and bark of boldo (Peumus boldus Molina), and has been shown to possess antioxidant activity and anti-inflammatory effects. From this point of view, the possible anti-diabetic effect of boldine and its mechanism were evaluated. The experiments were performed on male rats divided into four groups: control, boldine (100 mg kg(-1), daily in drinking water), diabetic [single dose of 80 mg kg(-1)of streptozotocin (STZ), i.p.] and diabetic simultaneously fed with boldine for 8 weeks. Diabetic status was evaluated periodically with changes of plasma glucose levels and body weight in rats. The effect of boldine on the STZ-induced diabetic rats was examined with the formation of malondialdehydes and carbonyls and the activities of endogenous antioxidant enzymes (superoxide dismutase and glutathione peroxidase) in mitochondria of the pancreas, kidney and liver. The scavenging action of boldine on oxygen free radicals and the effect on mitochondrial free-radical production were also investigated. The treatment of boldine attenuated the development of hyperglycemia and weight loss induced by STZ injection in rats. The levels of malondialdehyde (MDA) and carbonyls in liver, kidney and pancreas mitochondria were significantly increased in STZ-treated rats and decreased after boldine administration. The activities of mitochondrial manganese superoxide dismutase (MnSOD) in the liver, pancreas and kidney were significantly elevated in STZ-treated rats. Boldine administration decreased STZ-induced elevation of MnSOD activity in kidney and pancreas mitochondria, but not in liver mitochondria. In the STZ-treated group, glutathione peroxidase activities decreased in liver

  14. Iron Oxide Nanoparticles Induce Autophagosome Accumulation through Multiple Mechanisms: Lysosome Impairment, Mitochondrial Damage, and ER Stress.

    PubMed

    Zhang, Xudong; Zhang, Hongqiu; Liang, Xin; Zhang, Jinxie; Tao, Wei; Zhu, Xianbing; Chang, Danfeng; Zeng, Xiaowei; Liu, Gan; Mei, Lin

    2016-07-01

    Magnetite (iron oxide, Fe3O4) nanoparticles have been widely used for drug delivery and magnetic resonance imaging (MRI). Previous studies have shown that many metal-based nanoparticles including Fe3O4 nanoparticles can induce autophagosome accumulation in treated cells. However, the underlying mechanism is still not clear. To investigate the biosafety of Fe3O4 and PLGA-coated Fe3O4 nanoparticles, some experiments related to the mechanism of autophagy induction by these nanoparticles have been investigated. In this study, the results showed that Fe3O4, PLGA-coated Fe3O4, and PLGA nanoparticles could be taken up by the cells through cellular endocytosis. Fe3O4 nanoparticles extensively impair lysosomes and lead to the accumulation of LC3-positive autophagosomes, while PLGA-coated Fe3O4 nanoparticles reduce this destructive effect on lysosomes. Moreover, Fe3O4 nanoparticles could also cause mitochondrial damage and ER and Golgi body stresses, which induce autophagy, while PLGA-coated Fe3O4 nanoparticles reduce the destructive effect on these organelles. Thus, the Fe3O4 nanoparticle-induced autophagosome accumulation may be caused by multiple mechanisms. The autophagosome accumulation induced by Fe3O4 was also investigated. The Fe3O4, PLGA-coated Fe3O4, and PLGA nanoparticle-treated mice were sacrificed to evaluate the toxicity of these nanoparticles on the mice. The data showed that Fe3O4 nanoparticle treated mice would lead to the extensive accumulation of autophagosomes in the kidney and spleen in comparison to the PLGA-coated Fe3O4 and PLGA nanoparticles. Our data clarifies the mechanism by which Fe3O4 induces autophagosome accumulation and the mechanism of its toxicity on cell organelles and mice organs. These findings may have an important impact on the clinical application of Fe3O4 based nanoparticles. PMID:27287467

  15. Heme oxygenase-1 induction prevents neuronal damage triggered during mitochondrial inhibition: role of CO and bilirubin.

    PubMed

    Orozco-Ibarra, Marisol; Estrada-Sánchez, Ana María; Massieu, Lourdes; Pedraza-Chaverrí, José

    2009-06-01

    Heme oxygenase (HO) catalyzes the breakdown of heme to iron, carbon monoxide (CO), and biliverdin, the latter being further reduced to bilirubin (BR). A protective role of the inducible isoform, HO-1, has been described in pathological conditions associated with reactive oxygen species (ROS) and oxidative damage. The aim of this study was to investigate the role of HO-1 in the neurotoxicity induced by the mitochondrial toxin 3-nitropropionic acid (3-NP) in primary cultures of cerebellar granule neurons (CGNs). Toxicity of 3-NP is associated with ROS production, and this metabolic toxin has been used to mimic pathological conditions such as Huntington's disease. We found that cell death caused by 3-NP exposure was exacerbated by inhibition of HO with tin mesoporphyrin (SnMP). In addition, HO-1 up-regulation induced by the exposure to cobalt protoporphyrin (CoPP) before the incubation with 3-NP, prevented the cell death and the increase in ROS induced by 3-NP. Interestingly, addition of SnMP to CoPP-pretreated CGNs exposed to 3-NP, abolished the protective effect of CoPP suggesting that HO activity was responsible for this protective effect. This was additionally supported by the fact that CORM-2, a CO-releasing molecule, and BR, were able to protect against cell death and the increase in ROS induced by 3-NP. Our data clearly show that HO-1 elicits in CGNs a neuroprotective action against the neurotoxicity of 3-NP and that CO and BR may be involved, at least in part, in this protective effect. The present results increase our knowledge about the role of HO-1 in neuropathological conditions. PMID:19063990

  16. Low molecular weight guluronate prevents TNF-α-induced oxidative damage and mitochondrial dysfunction in C2C12 skeletal muscle cells.

    PubMed

    Dun, Yun-lou; Zhou, Xiao-lin; Guan, Hua-shi; Yu, Guang-li; Li, Chun-xia; Hu, Ting; Zhao, Xia; Cheng, Xiao-lei; He, Xiao-xi; Hao, Jie-jie

    2015-09-01

    Muscle wasting is associated with a variety of chronic or inflammatory disorders. Evidence suggests that inflammatory cytokines play a vital role in muscle inflammatory pathology and this may result in oxidative damage and mitochondrial dysfunction in skeletal muscle. In our study, we used microwave degradation to prepare a water-soluble low molecular weight guluronate (LMG) of 3000 Da from Fucus vesiculosus obtained from Canada, the Atlantic Ocean. We demonstrated the structural characteristics, using HPLC, FTIR and NMR of LMG and investigated its effects on oxidative damage and mitochondrial dysfunction in C2C12 skeletal muscle cells induced by tumor necrosis factor alpha (TNF-α), a cell inflammatory cytokine. The results indicated that LMG could alleviate mitochondrial reactive oxygen species (ROS) production, increase the activities of antioxidant enzymes (GSH and SOD), promote mitochondrial membrane potential (MMP) and upregulate the expression of mitochondrial respiratory chain protein in TNF-α-induced C2C12 cells. LMG supplement also increased the mitochondrial DNA copy number and mitochondrial biogenesis related genes in TNF-α-induced C2C12 cells. LMG may exert these protective effects through the nuclear factor kappa B (NF-κB) signaling pathway. These suggest that LMG is capable of protecting TNF-α-induced C2C12 cells against oxidative damage and mitochondrial dysfunction. PMID:26205038

  17. Pre-B-cell colony-enhancing factor protects against apoptotic neuronal death and mitochondrial damage in ischemia.

    PubMed

    Wang, Xiaowan; Li, Hailong; Ding, Shinghua

    2016-01-01

    We previously demonstrated that Pre-B-cell colony-enhancing factor (PBEF), also known as nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in mammalian NAD(+) biosynthesis pathway, plays a brain and neuronal protective role in ischemic stroke. In this study, we further investigated the mechanism of its neuroprotective effect after ischemia in the primary cultured mouse cortical neurons. Using apoptotic cell death assay, fluorescent imaging, molecular biology, mitochondrial biogenesis measurements and Western blotting analysis, our results show that the overexpression of PBEF in neurons can significantly promote neuronal survival, reduce the translocation of apoptosis inducing factor (AIF) from mitochondria to nuclei and inhibit the activation of capase-3 after glutamate-induced excitotoxicity. We further found that the overexpression of PBEF can suppress glutamate-induced mitochondrial fragmentation, the loss of mitochondrial DNA (mtDNA) content and the reduction of PGC-1 and NRF-1 expressions. Furthermore, these beneficial effects by PBEF are dependent on its enzymatic activity of NAD(+) synthesis. In summary, our study demonstrated that PBEF ameliorates ischemia-induced neuronal death through inhibiting caspase-dependent and independent apoptotic signaling pathways and suppressing mitochondrial damage and dysfunction. Our study provides novel insights into the mechanisms underlying the neuroprotective effect of PBEF, and helps to identify potential targets for ischemic stroke therapy. PMID:27576732

  18. Mentha piperita essential oil induces apoptosis in yeast associated with both cytosolic and mitochondrial ROS-mediated damage.

    PubMed

    Ferreira, Patrícia; Cardoso, Teresa; Ferreira, Filipa; Fernandes-Ferreira, Manuel; Piper, Peter; Sousa, Maria João

    2014-11-01

    Mentha piperita (MP), also known as peppermint, is an aromatic and medicinal plant widely used in the food industry, perfumery and cosmetic, pharmacy and traditional medicine. Its essential oil (EO) displays antimicrobial activity against a range of bacteria and fungi. In this study, we found that MP EO lethal cytotoxicity is associated with increased levels of intracellular reactive oxygen species, mitochondrial fragmentation and chromatin condensation, without loss of the plasma membrane integrity, indicative of an apoptotic process. Overexpression of cytosolic catalase and superoxide dismutases reverted the lethal effects of the EO and of its major component menthol. Conversely, deficiency in Sod1p (cytosolic copper-zinc-superoxide dismutase) greatly increased sensitivity to both agents, but deficiency in Sod2p (mitochondrial manganese superoxide dismutase) only induced sensitivity under respiratory growth conditions. Mentha piperita EO increased the frequency of respiratory deficient mutants indicative of damage to the mitochondrial genome, although increase in mitochondrial thiol oxidation does not seem to be involved in the EO toxicity. PMID:25065265

  19. Pre-B-cell colony-enhancing factor protects against apoptotic neuronal death and mitochondrial damage in ischemia

    PubMed Central

    Wang, Xiaowan; Li, Hailong; Ding, Shinghua

    2016-01-01

    We previously demonstrated that Pre-B-cell colony-enhancing factor (PBEF), also known as nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in mammalian NAD+ biosynthesis pathway, plays a brain and neuronal protective role in ischemic stroke. In this study, we further investigated the mechanism of its neuroprotective effect after ischemia in the primary cultured mouse cortical neurons. Using apoptotic cell death assay, fluorescent imaging, molecular biology, mitochondrial biogenesis measurements and Western blotting analysis, our results show that the overexpression of PBEF in neurons can significantly promote neuronal survival, reduce the translocation of apoptosis inducing factor (AIF) from mitochondria to nuclei and inhibit the activation of capase-3 after glutamate-induced excitotoxicity. We further found that the overexpression of PBEF can suppress glutamate-induced mitochondrial fragmentation, the loss of mitochondrial DNA (mtDNA) content and the reduction of PGC-1 and NRF-1 expressions. Furthermore, these beneficial effects by PBEF are dependent on its enzymatic activity of NAD+ synthesis. In summary, our study demonstrated that PBEF ameliorates ischemia-induced neuronal death through inhibiting caspase-dependent and independent apoptotic signaling pathways and suppressing mitochondrial damage and dysfunction. Our study provides novel insights into the mechanisms underlying the neuroprotective effect of PBEF, and helps to identify potential targets for ischemic stroke therapy. PMID:27576732

  20. DNA Damage and Repair in Vascular Disease.

    PubMed

    Uryga, Anna; Gray, Kelly; Bennett, Martin

    2016-01-01

    DNA damage affecting both genomic and mitochondrial DNA is present in a variety of both inherited and acquired vascular diseases. Multiple cell types show persistent DNA damage and a range of lesions. In turn, DNA damage activates a variety of DNA repair mechanisms, many of which are activated in vascular disease. Such DNA repair mechanisms either stall the cell cycle to allow repair to occur or trigger apoptosis or cell senescence to prevent propagation of damaged DNA. Recent evidence has indicated that DNA damage occurs early, is progressive, and is sufficient to impair function of cells composing the vascular wall. The consequences of persistent genomic and mitochondrial DNA damage, including inflammation, cell senescence, and apoptosis, are present in vascular disease. DNA damage can thus directly cause vascular disease, opening up new possibilities for both prevention and treatment. We review the evidence for and the causes, types, and consequences of DNA damage in vascular disease. PMID:26442438

  1. Activation of the Mitochondrial Apoptotic Pathway Produces Reactive Oxygen Species and Oxidative Damage in Hepatocytes That Contribute to Liver Tumorigenesis.

    PubMed

    Hikita, Hayato; Kodama, Takahiro; Tanaka, Satoshi; Saito, Yoshinobu; Nozaki, Yasutoshi; Nakabori, Tasuku; Shimizu, Satoshi; Hayashi, Yoshito; Li, Wei; Shigekawa, Minoru; Sakamori, Ryotaro; Miyagi, Takuya; Hiramatsu, Naoki; Tatsumi, Tomohide; Takehara, Tetsuo

    2015-08-01

    Chronic hepatitis, including viral hepatitis and steatihepatitis, is a well-known high-risk condition for hepatocellular carcinoma. We previously reported that continuous hepatocyte apoptosis drives liver tumors in hepatocyte-specific Bcl-xL or Mcl-1 knockout mice. In this study, we further examine the underlying cellular mechanisms of generating tumors in apoptosis-prone liver. In cultured hepatocytes, the administration of ABT-737, a Bcl-xL/-2/-w inhibitor, led to production of reactive oxygen species (ROS) as well as activation of caspases. Mitochondria isolated from murine liver, upon administration of truncated-Bid, a proapoptotic Bcl-2 family protein, released cytochrome c and produced ROS, which was dependent on mitochondrial respiration. Hepatic apoptosis, regeneration, accumulation of oxidative damages, and tumorigenesis observed in hepatocyte-specific Mcl-1 knockout mice were substantially attenuated by further deficiency of Bax or Bid, suggesting that a balance of mitochondrial Bcl-2 family proteins governs generation of oxidative stress and other pathologies. Whole-exome sequencing clarified that C>A/G>T transversion, which is often caused by oxidative DNA damage in proliferating cells, was a frequently observed mutation pattern in liver tumors of Mcl-1 knockout mice. The administration of antioxidant L-N-acetylcysteine did not affect apoptosis, compensatory regeneration, or fibrotic responses but significantly reduced oxidative DNA damage and incidence and multiplicity of live tumors in Mcl-1 knockout mice. In conclusion, activation of the mitochondrial apoptotic pathway in hepatocytes accumulates intracellular oxidative damages, leading to liver tumorigenesis, independently of liver regeneration or fibrosis. This study supports a concept that antioxidant therapy may be useful for suppressing liver carcinogenesis in patients with chronic liver disease. PMID:26038117

  2. Arsenic trioxide induces oxidative stress, DNA damage, and mitochondrial pathway of apoptosis in human leukemia (HL-60) cells

    PubMed Central

    2014-01-01

    Background Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), which accounts for approximately 10% of all acute myloid leukemia cases. It is a blood cancer that is formed by chromosomal mutation. Each year in the United States, APL affects about 1,500 patients of all age groups and causes approximately 1.2% of cancer deaths. Arsenic trioxide (ATO) has been used successfully for treatment of APL patients, and both induction and consolidated therapy have resulted in complete remission. Recently published studies from our laboratory have demonstrated that ATO pharmacology as an anti-leukemic drug is associated with cytotoxic and genotoxic effects in leukemia cells. Methods In the present study, we further investigated the detailed molecular mechanism of ATO-mediated intrinsic pathway of apoptosis; using HL-60 cells as a test model. Oxidative stress was assessed by spectrophotometric measurements of MDA and GSH levels while genotoxicity was determined by single cell gel electrophoresis (Comet assay). Apoptosis pathway was analyzed by Western blot analysis of Bax, Bcl2 and caspase 3 expression, as well as immunocytochemistry and confocal imaging of Bax and Cyt c translocation and mitochondrial membrane potential depolarization. Results ATO significantly (p < 0.05) induces oxidative stress, DNA damage, and caspase 3 activityin HL-60 cells in a dose-dependent manner. It also activated the intrinsic pathway of apoptosis by significantly modulating (p < 0.05) the expression and translocation of apoptotic molecules and decreasing the mitochondrial membrane potential in leukemia cells. Conclusion Taken together, our research demonstrated that ATO induces mitochondrial pathway of apoptosis in HL-60 cells. This apoptotic signaling is modulated via oxidative stress, DNA damage, and change in mitochondrial membrane potential, translocation and upregulation of apoptotic proteins leading programmed cell death. PMID:24887205

  3. Paternal DNA damage resulting from various sperm treatments persists after fertilization and is similar before and after DNA replication.

    PubMed

    Yamauchi, Yasuhiro; Riel, Jonathan M; Ward, Monika A

    2012-01-01

    In spite of its highly condensed state, sperm DNA is vulnerable to damage that can originate from oxidative stress, the activity of sperm-specific nucleases, or both. After fertilization, in the oocyte, paternal chromatin undergoes dramatic changes, and during this extensive remodeling, it can be both repaired and degraded, and these processes can be linked to DNA synthesis. Here, we analyzed sperm response to damage-inducing treatments both before and after fertilization and before or after zygotic DNA replication. Epididymal mouse spermatozoa were either frozen without cryoprotection (FT) or treated with detergent Triton X-100 coupled with dithiothreitol (TX+DTT) to induce DNA damage. Fresh, untreated sperm served as control. Immediately after preparation, spermatozoa from 3 groups were taken for comet assay, or for intracytoplasmic sperm injection into prometaphase I oocytes to visualize prematurely condensed single-chromatid chromosomes, or into mature metaphase II oocytes to visualize chromosomes after DNA replication. Comet assay revealed increased DNA fragmentation in treated sperm when compared with control, with FT sperm more severely affected. Chromosome analysis demonstrated paternal DNA damage in oocytes injected with treated, but not with fresh, sperm, with FT and TX+DTT groups now yielding similar damage. There were no differences in the incidence of abnormal paternal karyoplates before and after DNA synthesis in all examined groups. This study provides evidence that subjecting sperm to DNA damage-inducing treatments results in degradation of highly condensed sperm chromatin when it is still packed within the sperm head, and that this DNA damage persists after fertilization. The difference in DNA damage in sperm subjected to 2 treatments was ameliorated in the fertilized oocytes, suggesting that some chromatin repair might have occurred. This process, however, was independent of DNA synthesis and took place during oocyte maturation. PMID:21546611

  4. Two Strategies for the Development of Mitochondrial-Targeted Small Molecule Radiation Damage Mitigators

    PubMed Central

    Rwigema, Jean-Claude M.; Beck, Barbara; Wang, Wei; Doemling, Alexander; Epperly, Michael W.; Shields, Donna; Goff, Julie P.; Franicola, Darcy; Dixon, Tracy; Frantz, Marie-Céline; Wipf, Peter; Tyurina, Yulia; Kagan, Valerian E.; Wang, Hong; Greenberger, Joel S.

    2011-01-01

    Purpose To evaluate the effectiveness of mitigation of acute ionizing radiation damage by mitochondria-targeted small molecules. Materials and Methods We evaluated the nitroxide-linked alkene peptide isostere JP4-039, the nitric oxide synthase inhibitor-linked alkene peptide esostere MCF201-89, and the p53/mdm2/mdm4 inhibitor BEB55 in radiation mitigation by clonogenic survival curves with the murine hematopoietic progenitor cell line 32D cl 3, human bone marrow stromal (KM101) and pulmonary epithelial (IB3) cell line. The p53 dependent mechanism of action was tested with p53 +/+ and p53 −/− murine bone marrow stromal cell lines. C57BL/6 NHsd female mice were injected I.P. after 9.5 Gy total body irradiation (TBI) with JP4-039, MCF201-89, or BEB55 individually or in combination. Results Each drug, JP4-039, MCF201-89, or BEB55, individually or as a mixture of all 3 compounds, increased the survival of 32D cl 3 cells and IB3 cells significantly over control irradiated cells (p=0.0021, p=0.0011, p=0.0038, and p=0.0073, respectively), and (p=0.0193, p=0.0452, p=0.0017, and p=0.0019 respectively). KM101 cells were protected by individual drugs (p=0.0007, p=0.0235, p=0.0044, respectively). JP4-039 and MCF201-89 increased irradiation survival of both p53+/+ (p=0.0396 and p=0.0071, respectively) and p53−/− cells (p=0.0007 and p=0.0188 respectively), while BEB55 was ineffective with (p53−/−) cells. Drugs administered individually or as a mixtures of all 3 after TBI significantly increased mouse survival (p=0.0234, 0.0009, 0.0052 and 0.0167 respectively). Conclusion Mitochondrial targeting of small molecule radiation mitigators decreases irradiation-induced cell death in vitro and prolongs survival of lethally irradiated mice. PMID:21493014

  5. Persistent DNA damage-induced premature senescence alters the functional features of human bone marrow mesenchymal stem cells.

    PubMed

    Minieri, Valentina; Saviozzi, Silvia; Gambarotta, Giovanna; Lo Iacono, Marco; Accomasso, Lisa; Cibrario Rocchietti, Elisa; Gallina, Clara; Turinetto, Valentina; Giachino, Claudia

    2015-04-01

    Human mesenchymal stem cells (hMSCs) are adult multipotent stem cells located in various tissues, including the bone marrow. In contrast to terminally differentiated somatic cells, adult stem cells must persist and function throughout life to ensure tissue homeostasis and repair. For this reason, they must be equipped with DNA damage responses able to maintain genomic integrity while ensuring their lifelong persistence. Evaluation of hMSC response to genotoxic insults is of great interest considering both their therapeutic potential and their physiological functions. This study aimed to investigate the response of human bone marrow MSCs to the genotoxic agent Actinomycin D (ActD), a well-known anti-tumour drug. We report that hMSCs react by undergoing premature senescence driven by a persistent DNA damage response activation, as hallmarked by inhibition of DNA synthesis, p21 and p16 protein expression, marked Senescent Associated β-galactosidase activity and enlarged γH2AX foci co-localizing with 53BP1 protein. Senescent hMSCs overexpress several senescence-associated secretory phenotype (SASP) genes and promote motility of lung tumour and osteosarcoma cell lines in vitro. Our findings disclose a multifaceted consequence of ActD treatment on hMSCs that on the one hand helps to preserve this stem cell pool and prevents damaged cells from undergoing neoplastic transformation, and on the other hand alters their functional effects on the surrounding tissue microenvironment in a way that might worsen their tumour-promoting behaviour. PMID:25619736

  6. ER–Mitochondrial Calcium Flow Underlies Vulnerability of Mechanosensory Hair Cells to Damage

    PubMed Central

    Esterberg, Robert; Hailey, Dale W.

    2014-01-01

    Mechanosensory hair cells are vulnerable to environmental insult, resulting in hearing and balance disorders. We demonstrate that directional compartmental flow of intracellular Ca2+ underlies death in zebrafish lateral line hair cells after exposure to aminoglycoside antibiotics, a well characterized hair cell toxin. Ca2+ is mobilized from the ER and transferred to mitochondria via IP3 channels with little cytoplasmic leakage. Pharmacological agents that shunt ER-derived Ca2+ directly to cytoplasm mitigate toxicity, indicating that high cytoplasmic Ca2+ levels alone are not cytotoxic. Inhibition of the mitochondrial transition pore sensitizes hair cells to the toxic effects of aminoglycosides, contrasting with current models of excitotoxicity. Hair cells display efficient ER–mitochondrial Ca2+ flow, suggesting that tight coupling of these organelles drives mitochondrial activity under physiological conditions at the cost of increased susceptibility to toxins. PMID:25031409

  7. NP04634 prevents cell damage caused by calcium overload and mitochondrial disruption in bovine chromaffin cells.

    PubMed

    Valero, Teresa; del Barrio, Laura; Egea, Javier; Cañas, Noelia; Martínez, Ana; García, Antonio G; Villarroya, Mercedes; López, Manuela G

    2009-04-01

    Marine sponges are becoming a rich source of potential new medicines. NP04634 is a synthetic derivative of 11,19 dideoxyfistularin, a natural product of the Mediterranean sponge Aplysina cavernicola. We report the cytoprotective effects of this new compound in isolated bovine chromaffin cells exposed to cytotoxic stimuli that have been related to neuronal cell death, i.e. Ca(2+) overload and mitochondrial dysfunction. Cell death was achieved by: (i) causing Ca(2+) overload through voltage-dependent calcium channels by exposing the cells to 30 mM K(+), 5 mM Ca(2+) plus 0.3 microM FPL64176 (an L-type Ca(2+)-channel activator); (ii) incubating the cells with veratridine, causing cytosolic Ca(2+) concentration ([Ca(2+)](c)) oscillations and mitochondrial disruption; and (iii) blocking mitochondrial complexes I and V using a combination of 30 microM rotenone and 10 microM oligomycin. At 10 microM, NP04634 caused significant protection against 30K(+)/5Ca(2+)/FPL-induced toxicity. NP04634 caused a concentration-dependent reduction in [Ca(2+)](c) induced by 70 mM K(+) in cells loaded with Fluo-4; maximum blockade was 67% at 30 microM. Veratridine caused continuous [Ca(2+)](c) oscillations that translated into 43.4+/-2% cell death. In this model, NP04634 caused 42% and 67% protection at 3 and 10 microM, respectively. NP04634 reduced [Ca(2+)](c) oscillations and mitochondrial depolarization caused by veratridine. NP04634 at 10 microM also protected against mitochondrial disruption caused by rotenone plus oligomycin. In conclusion, NP04634 is a novel compound of marine origin with cytoprotective properties that might have potential therapeutic implications under pathological circumstances involving Ca(2+) overload and mitochondrial disruption, such as in certain neurodegenerative diseases and/or stroke. PMID:19233161

  8. The marine toxin palytoxin induces necrotic death in HaCaT cells through a rapid mitochondrial damage.

    PubMed

    Pelin, Marco; Sosa, Silvio; Pacor, Sabrina; Tubaro, Aurelia; Florio, Chiara

    2014-09-17

    Palytoxin (PLTX) is one of the most toxic algal biotoxin known so far. It transforms the Na(+)/K(+)-ATPase into a cationic channel inducing a massive intracellular Na(+) influx. However, from a mechanistic point of view, the features and the intracellular pathways leading to PLTX-induced cell death are still not completely characterized. This study on skin HaCaT keratinocytes demonstrates that PLTX induces necrosis since propidium iodide uptake was observed already after 1 h toxin exposure, an effect that was not lowered by toxin removal. Furthermore, necrotic-like morphological alterations were evidenced by confocal microscopy. Apoptosis occurrence was excluded since no caspases 3/7, caspase 8, and caspase 9 activation as well as no apoptotic bodies formation were recorded. Necrosis was preceded by a very early mitochondrial damage as indicated by JC-1 fluorescence shift, recorded already after 5 min toxin exposure. This shift was totally abolished when Na(+) and Ca(2+) ions were withdrawn from culture medium, whereas cyclosporine-A was ineffective, excluding the occurrence of a controlled biochemical response. These results clearly establish necrosis as the primary mechanism for PLTX-induced cell death in HaCaT cells. The rapidity of mitochondrial damage and the consequent irreversible necrosis rise serious concerns about the very fast onset of PLTX toxic effects. PMID:25066017

  9. Spatiotemporal autophagic degradation of oxidatively damaged organelles after photodynamic stress is amplified by mitochondrial reactive oxygen species

    PubMed Central

    Rubio, Noemi; Coupienne, Isabelle; Di Valentin, Emmanuel; Heirman, Ingeborg; Grooten, Johan; Piette, Jacques; Agostinis, Patrizia

    2012-01-01

    Although reactive oxygen species (ROS) have been reported to evoke different autophagic pathways, how ROS or their secondary products modulate the selective clearance of oxidatively damaged organelles is less explored. To investigate the signaling role of ROS and the impact of their compartmentalization in autophagy pathways, we used murine fibrosarcoma L929 cells overexpressing different antioxidant enzymes targeted to the cytosol or mitochondria and subjected them to photodynamic (PD) stress with the endoplasmic reticulum (ER)-associated photosensitizer hypericin. We show that following apical ROS-mediated damage to the ER, predominantly cells overexpressing mitochondria-associated glutathione peroxidase 4 (GPX4) and manganese superoxide dismutase (SOD2) displayed attenuated kinetics of autophagosome formation and overall cell death, as detected by computerized time-lapse microscopy. Consistent with a primary ER photodamage, kinetics and colocalization studies revealed that photogenerated ROS induced an initial reticulophagy, followed by morphological changes in the mitochondrial network that preceded clearance of mitochondria by mitophagy. Overexpression of cytosolic and mitochondria-associated GPX4 retained the tubular mitochondrial network in response to PD stress and concomitantly blocked the progression toward mitophagy. Preventing the formation of phospholipid hydroperoxides and H2O2 in the cytosol as well as in the mitochondria significantly reduced cardiolipin peroxidation and apoptosis. All together, these results show that in response to apical ER photodamage ROS propagate to mitochondria, which in turn amplify ROS production, thereby contributing to two antagonizing processes, mitophagy and apoptosis. PMID:22889744

  10. Activation of mitochondrial STAT-3 and reduced mitochondria damage during hypothermia treatment for post-cardiac arrest myocardial dysfunction.

    PubMed

    Huang, Chien-Hua; Tsai, Min-Shan; Chiang, Chih-Yen; Su, Yu-Jen; Wang, Tzung-Dau; Chang, Wei-Tien; Chen, Huei-Wen; Chen, Wen-Jone

    2015-11-01

    While therapeutic hypothermia improves the outcomes of individuals in cardiac arrest, the hemodynamic responses and mechanisms which underlie hypothermia-induced cardioprotection are not fully understood. Therefore, we investigated the mechanism by which induced hypothermia preserves cardiac function and protects against mitochondrial damage following cardiac arrest. Cardiac arrest was induced in adult male Wistar rats by asphyxiation for 8.5 min. Following resuscitation, the animals were randomly assigned to a hypothermia (32 °C) or normothermia (37 °C) group. Monitoring results showed that cardiac output at the fourth hour after resuscitation was significantly better in rats treated with hypothermia when compared to rats treated with normothermia (P < 0.01). Examinations by transmission electron microscopy showed that mitochondria in the left ventricle of rats in the hypothermia group were significantly less swollen compared to such mitochondria in the normothermia group (P < 0.001). Additionally, opening of mitochondrial permeability transition pores occurred less frequently in the hypothermic group. While complex I/III activity in the electron transport reaction was damaged after cardiac arrest and resuscitation, the degree of injury was ameliorated by hypothermia treatment (P < 0.05). The amount of STAT-3 phosphorylated at tyrosine 705 and its expression in mitochondria were significantly higher under hypothermia treatment compared to normothermia treatment. In vitro studies showed that inhibition STAT-3 activation abolished the ability of hypothermia to protect H9C2 cardiomyocytes against injury produced by simulated ischemia and reperfusion. Therapeutic hypothermia treatment can ameliorate cardiac dysfunction and help preserve both mitochondrial integrity and electron transport activity. PMID:26471891

  11. Apoptosis and non-inflammatory phagocytosis can be induced by mitochondrial damage without caspases.

    PubMed

    van Delft, M F; Smith, D P; Lahoud, M H; Huang, D C S; Adams, J M

    2010-05-01

    A central issue regarding vertebrate apoptosis is whether caspase activity is essential, particularly for its crucial biological outcome: non-inflammatory clearance of the dying cell. Caspase-9 is required for the proteolytic cascade unleashed by the mitochondrial outer membrane permeabilization (MOMP) regulated by the Bcl-2 protein family. However, despite the severely blunted apoptosis in cells from Casp9(-/-) mice, some organs with copious apoptosis, such as the thymus, appear unaffected. To address this paradox, we investigated how caspase-9 loss affects apoptosis and clearance of mouse fibroblasts and thymocytes. Although Casp9(-/-) cells were initially refractory to apoptotic insults, they eventually succumbed to slower caspase-independent cell death. Furthermore, in gamma-irradiated mice, the dying Casp9(-/-) thymocytes were efficiently cleared, without apparent inflammation. Notably, MOMP proceeded normally, and the impaired mitochondrial function, revealed by diminished mitochondrial membrane potential (DeltaPsi(m)), committed cells to die, as judged by loss of clonogenicity. Upon the eventual full collapse of DeltaPsi(m), presumably reflecting failure of respiration, intact dying Casp9(-/-) cells unexpectedly exposed the prototypic 'eat-me' signal phosphatidylserine, which allowed their recognition and engulfment by phagocytes without overt inflammation. Hence, caspase-9-induced proteolysis accelerates apoptosis, but impaired mitochondrial integrity apparently triggers a default caspase-independent program of cell death and non-inflammatory clearance. Thus, caspases appear dispensable for some essential biological functions of apoptosis. PMID:19911005

  12. Oxidative Stress in Cardiac Mitochondria Caused by Copper Deficiency May Be Insufficient to Damage Mitochondrial Proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper (Cu) deficiency may promote the generation of reactive oxygen species (ROS) by the mitochondrial electron transport chain through inhibition of cytochrome c oxidase (CCO) and increased reduction of respiratory complexes upstream from CCO. In the present study, respiration, H2O2 production and...

  13. Apoptosis and non-inflammatory phagocytosis can be induced by mitochondrial damage without caspases

    PubMed Central

    van Delft, Mark F.; Smith, Darrin P.; Lahoud, Mireille H.; Huang, David C.S.; Adams, Jerry M.

    2010-01-01

    A central issue regarding vertebrate apoptosis is whether caspase activity is essential, particularly for its crucial biological outcome, non-inflammatory clearance of the dying cell. Caspase-9 is required for the proteolytic cascade unleashed by the mitochondrial outer membrane permeabilization (MOMP) regulated by the Bcl-2 protein family. However, despite the severely blunted apoptosis in cells from Casp9−/− mice, some organs with copious apoptosis, such as the thymus, appear unaffected. To address this paradox, we investigated how caspase-9 loss affects apoptosis and clearance of mouse fibroblasts and thymocytes. Although Casp9−/− cells were initially refractory to apoptotic insults, they eventually succumbed to slower caspase-independent cell death. Furthermore, in γ-irradiated mice, the dying Casp9−/− thymocytes were efficiently cleared, without apparent inflammation. Notably, MOMP proceeded normally, and the impaired mitochondrial function, revealed by diminished mitochondrial membrane potential (Δψm), committed cells to die, as judged by loss of clonogenicity. Upon the eventual full collapse of Δψm, presumably reflecting failure of respiration, intact dying Casp9−/− cells unexpectedly exposed the prototypic “eat-me” signal phosphatidylserine, which allowed their recognition and engulfment by phagocytes without overt inflammation. Hence, caspase-9-induced proteolysis accelerates apoptosis, but impaired mitochondrial integrity apparently triggers a default caspase-independent program of cell death and non-inflammatory clearance. Thus, caspases appear dispensable for some essential biological functions of apoptosis. PMID:19911005

  14. Changes in DNA damage, molecular integrity, and copy number for plastid DNA and mitochondrial DNA during maize development.

    PubMed

    Kumar, Rachana A; Oldenburg, Delene J; Bendich, Arnold J

    2014-12-01

    The amount and structural integrity of organellar DNAs change during plant development, although the mechanisms of change are poorly understood. Using PCR-based methods, we quantified DNA damage, molecular integrity, and genome copy number for plastid and mitochondrial DNAs of maize seedlings. A DNA repair assay was also used to assess DNA impediments. During development, DNA damage increased and molecules with impediments that prevented amplification by Taq DNA polymerase increased, with light causing the greatest change. DNA copy number values depended on the assay method, with standard real-time quantitative PCR (qPCR) values exceeding those determined by long-PCR by 100- to 1000-fold. As the organelles develop, their DNAs may be damaged in oxidative environments created by photo-oxidative reactions and photosynthetic/respiratory electron transfer. Some molecules may be repaired, while molecules with unrepaired damage may be degraded to non-functional fragments measured by standard qPCR but not by long-PCR. PMID:25261192

  15. Changes in DNA damage, molecular integrity, and copy number for plastid DNA and mitochondrial DNA during maize development

    PubMed Central

    Kumar, Rachana A.; Oldenburg, Delene J.; Bendich, Arnold J.

    2014-01-01

    The amount and structural integrity of organellar DNAs change during plant development, although the mechanisms of change are poorly understood. Using PCR-based methods, we quantified DNA damage, molecular integrity, and genome copy number for plastid and mitochondrial DNAs of maize seedlings. A DNA repair assay was also used to assess DNA impediments. During development, DNA damage increased and molecules with impediments that prevented amplification by Taq DNA polymerase increased, with light causing the greatest change. DNA copy number values depended on the assay method, with standard real-time quantitative PCR (qPCR) values exceeding those determined by long-PCR by 100- to 1000-fold. As the organelles develop, their DNAs may be damaged in oxidative environments created by photo-oxidative reactions and photosynthetic/respiratory electron transfer. Some molecules may be repaired, while molecules with unrepaired damage may be degraded to non-functional fragments measured by standard qPCR but not by long-PCR. PMID:25261192

  16. Mitochondrial DNA Alterations and Reduced Mitochondrial Function in Aging

    PubMed Central

    Hebert, Sadie L.; Lanza, Ian R.; Nair, K. Sreekumaran

    2010-01-01

    Oxidative damage to mitochondrial DNA increases with aging. This damage has the potential to affect mitochondrial DNA replication and transcription which could alter the abundance or functionality of mitochondrial proteins. This review describes mitochondrial DNA alterations and changes in mitochondrial function that occur with aging. Age-related alterations in mitochondrial DNA as a possible contributor to the reduction in mitochondrial function are discussed. PMID:20307565

  17. Impaired enzymatic defensive activity, mitochondrial dysfunction and proteasome activation are involved in RTT cell oxidative damage.

    PubMed

    Cervellati, Carlo; Sticozzi, Claudia; Romani, Arianna; Belmonte, Giuseppe; De Rasmo, Domenico; Signorile, Anna; Cervellati, Franco; Milanese, Chiara; Mastroberardino, Pier Giorgio; Pecorelli, Alessandra; Savelli, Vinno; Forman, Henry J; Hayek, Joussef; Valacchi, Giuseppe

    2015-10-01

    A strong correlation between oxidative stress (OS) and Rett syndrome (RTT), a rare neurodevelopmental disorder affecting females in the 95% of the cases, has been well documented although the source of OS and the effect of a redox imbalance in this pathology has not been yet investigated. Using freshly isolated skin fibroblasts from RTT patients and healthy subjects, we have demonstrated in RTT cells high levels of H2O2 and HNE protein adducts. These findings correlated with the constitutive activation of NADPH-oxidase (NOX) and that was prevented by a NOX inhibitor and iron chelator pre-treatment, showing its direct involvement. In parallel, we demonstrated an increase in mitochondrial oxidant production, altered mitochondrial biogenesis and impaired proteasome activity in RTT samples. Further, we found that the key cellular defensive enzymes: glutathione peroxidase, superoxide dismutase and thioredoxin reductases activities were also significantly lower in RTT. Taken all together, our findings suggest that the systemic OS levels in RTT can be a consequence of both: increased endogenous oxidants as well as altered mitochondrial biogenesis with a decreased activity of defensive enzymes that leads to posttranslational oxidant protein modification and a proteasome activity impairment. PMID:26189585

  18. Arsenic-induced mitochondrial oxidative damage is mediated by decreased PGC-1α expression and its downstream targets in rat brain.

    PubMed

    Prakash, Chandra; Kumar, Vijay

    2016-08-25

    The present study was carried out to investigate the molecular mechanism of arsenic-induced mitochondrial oxidative damage and its relation to biogenesis in rat brain. Chronic sodium arsenite (25 ppm, orally) administration for 12 weeks decreased mitochondrial complexes activities and mRNA expression of selective complexes subunits. The expression of mitochondrial biogenesis regulator PGC-1α, and its downstream targets NRF-1, NRF-2 and Tfam were decreased significantly both at mRNA and protein levels suggesting impaired biogenesis following chronic arsenic-exposure. In addition to this, protein expression analysis also revealed activation of Bax and caspase-3, leading to translocation of cytochrome c from mitochondria to cytosol suggesting induction of apoptotic pathway under oxidative stress. This was further confirmed by electron microscopy study which depicted morphological changes in mitochondria in terms of altered nuclear and mitochondrial shape and chromatin condensation in arsenic-treated rats. The immunohistochemical studies showed both nuclear and cytosolic localization of NRF-1 and NRF-2 in arsenic-exposed rat brain further suggesting regulatory role of these transcription factors under arsenic neurotoxicity. The results of present study indicate that arsenic-induced mitochondrial oxidative damage is associated with decreased mitochondrial biogenesis in rat brain that may present as important target to reveal the mechanism for arsenic-induced neurotoxicity. PMID:27425645

  19. Redox regulation of mitochondrial fission, protein misfolding, synaptic damage, and neuronal cell death: potential implications for Alzheimer’s and Parkinson’s diseases

    PubMed Central

    Nakamura, Tomohiro

    2010-01-01

    Normal mitochondrial dynamics consist of fission and fusion events giving rise to new mitochondria, a process termed mitochondrial biogenesis. However, several neurodegenerative disorders manifest aberrant mitochondrial dynamics, resulting in morphological abnormalities often associated with deficits in mitochondrial mobility and cell bioenergetics. Rarely, dysfunctional mitochondrial occur in a familial pattern due to genetic mutations, but much more commonly patients manifest sporadic forms of mitochondrial disability presumably related to a complex set of interactions of multiple genes (or their products) with environmental factors (G × E). Recent studies have shown that generation of excessive nitric oxide (NO), in part due to generation of oligomers of amyloid-β (Aβ) protein or overactivity of the NMDA-subtype of glutamate receptor, can augment mitochondrial fission, leading to frank fragmentation of the mitochondria. S-Nitrosylation, a covalent redox reaction of NO with specific protein thiol groups, represents one mechanism contributing to NO-induced mitochondrial fragmentation, bioenergetic failure, synaptic damage, and eventually neuronal apoptosis. Here, we summarize our evidence in Alzheimer’s disease (AD) patients and animal models showing that NO contributes to mitochondrial fragmentation via S-nitrosylation of dynamin-related protein 1 (Drp1), a protein involved in mitochondrial fission. These findings may provide a new target for drug development in AD. Additionally, we review emerging evidence that redox reactions triggered by excessive levels of NO can contribute to protein misfolding, the hallmark of a number of neurodegenerative disorders, including AD and Parkinson’s disease. For example, S-nitrosylation of parkin disrupts its E3 ubiquitin ligase activity, and thereby affects Lewy body formation and neuronal cell death. PMID:20177970

  20. Induction and persistence of radiation-induced DNA damage is more pronounced in young animals than in old animals

    PubMed Central

    Hudson, Darryl; Kovalchuk, Igor; Koturbash, Igor; Kolb, Bryan; Martin, Olga A.; Kovalchuk, Olga

    2011-01-01

    Younger individuals are more prone to develop cancer upon ionizing radiation (IR) exposure. Radiation-induced tumors are associated with inefficient repair of IR-induced DNA damage and genome instability. Phosphorylation of histone H2AX (γ-H2AX) is the initial event in repair of IR-induced DNA damage on the chromatin flanking the DNA strand breaks. This step is crucially important for the repair of DNA strand breaks and for the maintenance of genome stability. We studied the molecular underpinnings of the age-related IR effects using an animal model. By assaying for IR-induced γ-H2AX foci we analyzed the induction and repair of the DNA strand breaks in spleen, thymus, liver, lung, kidney, cerebellum, hippocampus, frontal cortex and olfactory bulb of 7, 14, 24, 30 and 45 days old male and female mice as a function of age. We demonstrate that tissues of younger animals are much more susceptible to IR-induced DNA damage. Younger animals exhibited higher levels of γ-H2AX formation which partially correlated with cellular proliferation and expression of DNA repair proteins. Induction and persistence of γ-H2AX foci was the highest in lymphoid organs (thymus and spleen) of 7 and 14 day old mice. The lowest focal induction was seen in lung and brain of young animals. The mechanisms of cell and tissue-specificity of in vivo IR responses need to be further dissected. This study provides a roadmap for the future analyses of DNA damage and repair induction in young individuals. PMID:21685513

  1. Low-molecular-weight polyphenols protect kidney damage through suppressing NF-κB and modulating mitochondrial biogenesis in diabetic db/db mice.

    PubMed

    Liu, Hung-Wen; Wei, Chu-Chun; Chang, Sue-Joan

    2016-04-20

    Hyperglycemia, increased inflammatory responses, and dysregulation of mitochondrial function accompanied by type 2 diabetes may eventually lead to kidney damage. We examined the protective effects of oligonol, a low-molecular-weight polyphenol derived from lychee fruit and green tea, on kidney damage in diabetic db/db mice. Dietary oligonol supplementation lowered glucose and insulin levels and improved oral glucose tolerance. Oligonol attenuated serum resistin and IL-6 levels and reduced glomerular hypertrophy and mesangial matrix expansion caused by diabetes. Oligonol reduced activation of nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase. Suppressed renal oxidative stress by oligonol was associated with stimulated sirtuin1 expression and restored AMP-activated kinase protein α activity, mitochondrial DNA copy number, and mitochondrial biogenesis associated genes including nuclear respiratory factor 1 and mitochondrial transcription factor A. In conclusion, oligonol reduced fasting glucose level, improved insulin sensitivity, suppressed inflammatory responses, and upregulated metabolic regulators involved in mitochondrial biogenesis, thereby leading to protection against diabetes-induced kidney damage. PMID:26960417

  2. Mitochondrial ATP-sensitive potassium channel opening inhibits isoproterenol-induced cardiac hypertrophy by preventing oxidative damage.

    PubMed

    Lemos Caldas, Francisco Rodrigo; Rocha Leite, Iago Mateus; Tavarez Filgueiras, Ana Beatriz; de Figueiredo Júnior, Isaias Lima; Gomes Marques de Sousa, Tereza Amália; Martins, Pamela Reis; Kowaltowski, Alicia Juliana; Fernandes Facundo, Heberty di Tarso

    2015-04-01

    Cardiac hypertrophy is a chronic complex disease that occurs in response to hemodynamic load and is accompanied by oxidative stress and mitochondrial dysfunction. Mitochondrial ATP-sensitive K channels (mitoKATPs) have previously been shown to prevent oxidative cardiac damage under conditions of ischemia/reperfusion. However, the effect of these channels on cardiac hypertrophy has not been tested to date. In this study, we show that treatment of Swiss mice with isoproterenol (30 mg·kg·d) induces cardiac hypertrophy while significantly decreasing the levels of reduced protein thiols, glutathione, catalase, and superoxide dismutase activity, indicative of a condition of oxidative imbalance. Treatment with diazoxide (a mitoKATP opener, 5 mg·kg·d) normalized the levels of protein thiols and reduced glutathione, rescued superoxide dismutase activity, and significantly prevented cardiac hypertrophy. The protective effects of diazoxide were mitigated by the mitoKATP blockers 5-hydroxydecanoate (5 mg·kg·d) and glibenclamide (3 mg·kg·d), demonstrating that they were related to activation of the channel. Taken together, our results establish that mitoKATP activation promotes very robust prevention of cardiac hypertrophy and associated oxidative imbalance and suggest that these channels can be important drug targets for the pharmacological control of cardiac hypertrophy. PMID:25850726

  3. Ophiopogonin D attenuates doxorubicin-induced autophagic cell death by relieving mitochondrial damage in vitro and in vivo.

    PubMed

    Zhang, Ying-Yu; Meng, Chen; Zhang, Xin-Mu; Yuan, Cai-Hua; Wen, Ming-Da; Chen, Zhong; Dong, Da-Chuan; Gao, Yan-Hong; Liu, Chang; Zhang, Zhao

    2015-01-01

    It has been reported that ophiopogonin D (OP-D), a steroidal glycoside and an active component extracted from Ophiopogon japonicas, promotes antioxidative protection of the cardiovascular system. However, it is unknown whether OP-D exerts protective effects against doxorubicin (DOX)-induced autophagic cardiomyocyte injury. Here, we demonstrate that DOX induced excessive autophagy through the generation of reactive oxygen species (ROS) in H9c2 cells and in mouse hearts, which was indicated by a significant increase in the number of autophagic vacuoles, LC3-II/LC3-I ratio, and upregulation of the expression of GFP-LC3. Pretreatment with OP-D partially attenuated the above phenomena, similar to the effects of treatment with 3-methyladenine. In addition, OP-D treatment significantly relieved the disruption of the mitochondrial membrane potential by antioxidative effects through downregulating the expression of both phosphorylated c-Jun N-terminal kinase and extracellular signal-regulated kinase. The ability of OP-D to reduce the generation of ROS due to mitochondrial damage and, consequently, to inhibit autophagic activity partially accounts for its protective effects in the hearts against DOX-induced toxicity. PMID:25378375

  4. The human MSH5 (MutSHomolog 5) protein localizes to mitochondria and protects the mitochondrial genome from oxidative damage.

    PubMed

    Bannwarth, Sylvie; Figueroa, Alexia; Fragaki, Konstantina; Destroismaisons, Laurie; Lacas-Gervais, Sandra; Lespinasse, Françoise; Vandenbos, Fanny; Pradelli, Ludivine A; Ricci, Jean-Ehrland; Rötig, Agnès; Michiels, Jean-François; Vande Velde, Christine; Paquis-Flucklinger, Véronique

    2012-11-01

    MutS homologs play a central role in maintaining genetic stability. We show that MSH5 (MutSHomolog 5) is localized into the mitochondria of germ and somatic cells. This protein binds to mtDNA and interacts with the Twinkle helicase and the DNA polymerase gamma. hMSH5 stimulates mtDNA repair in response to DNA damage induced by oxidative stress. Furthermore, we observed a subsarcolemmal accumulation of hMSH5 in COX negative muscle fibers of patients presenting a mitochondrial myopathy. We report a novel localization for hMSH5 suggesting that this protein may have functions other than those known in meiotic recombination. PMID:22917773

  5. Persistence of Gender Related-Effects on Visuo-Spatial and Verbal Working Memory in Right Brain-Damaged Patients

    PubMed Central

    Piccardi, Laura; Matano, Alessandro; D’Antuono, Giovanni; Marin, Dario; Ciurli, Paola; Incoccia, Chiara; Verde, Paola; Guariglia, Paola

    2016-01-01

    The aim of the present study was to verify if gender differences in verbal and visuo-spatial working memory would persist following right cerebral lesions. To pursue our aim we investigated a large sample (n. 346) of right brain-damaged patients and healthy participants (n. 272) for the presence of gender effects in performing Corsi and Digit Test. We also assessed a subgroup of patients (n. 109) for the nature (active vs. passive) of working memory tasks. We tested working memory (WM) administering the Corsi Test (CBT) and the Digit Span (DS) using two different versions: forward (fCBT and fDS), subjects were required to repeat stimuli in the same order that they were presented; and backward (bCBT and bDS), subjects were required to repeat stimuli in the opposite order of presentation. In this way, passive storage and active processing of working memory were assessed. Our results showed the persistence of gender-related effects in spite of the presence of right brain lesions. We found that men outperformed women both in CBT and DS, regardless of active and passive processing of verbal and visuo-spatial stimuli. The presence of visuo-spatial disorders (i.e., hemineglect) can affect the performance on Corsi Test. In our sample, men and women were equally affected by hemineglect, therefore it did not mask the gender effect. Generally speaking, the persistence of the men’s superiority in visuo-spatial tasks may be interpreted as a protective factor, at least for men, within other life factors such as level of education or kind of profession before retirement. PMID:27445734

  6. Persistence of Gender Related-Effects on Visuo-Spatial and Verbal Working Memory in Right Brain-Damaged Patients.

    PubMed

    Piccardi, Laura; Matano, Alessandro; D'Antuono, Giovanni; Marin, Dario; Ciurli, Paola; Incoccia, Chiara; Verde, Paola; Guariglia, Paola

    2016-01-01

    The aim of the present study was to verify if gender differences in verbal and visuo-spatial working memory would persist following right cerebral lesions. To pursue our aim we investigated a large sample (n. 346) of right brain-damaged patients and healthy participants (n. 272) for the presence of gender effects in performing Corsi and Digit Test. We also assessed a subgroup of patients (n. 109) for the nature (active vs. passive) of working memory tasks. We tested working memory (WM) administering the Corsi Test (CBT) and the Digit Span (DS) using two different versions: forward (fCBT and fDS), subjects were required to repeat stimuli in the same order that they were presented; and backward (bCBT and bDS), subjects were required to repeat stimuli in the opposite order of presentation. In this way, passive storage and active processing of working memory were assessed. Our results showed the persistence of gender-related effects in spite of the presence of right brain lesions. We found that men outperformed women both in CBT and DS, regardless of active and passive processing of verbal and visuo-spatial stimuli. The presence of visuo-spatial disorders (i.e., hemineglect) can affect the performance on Corsi Test. In our sample, men and women were equally affected by hemineglect, therefore it did not mask the gender effect. Generally speaking, the persistence of the men's superiority in visuo-spatial tasks may be interpreted as a protective factor, at least for men, within other life factors such as level of education or kind of profession before retirement. PMID:27445734

  7. Persistence and protection of mitochondrial DNA in the generative cell of cucumber is consistent with its paternal transmission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucumber, unlike most plants, shows paternal inheritance of its mitochondrial DNA (mtDNA); however, the mechanisms regulating this unique transmission mode are unclear. Here we monitored the amounts of mtDNA through the development of cucumber microspores to pollen and observed that mtDNA decreases ...

  8. Brain zinc chelation by diethyldithiocarbamate increased the behavioral and mitochondrial damages in zebrafish subjected to hypoxia

    PubMed Central

    Braga, Marcos M.; Silva, Emerson S.; Moraes, Tarsila B.; Schirmbeck, Gabriel Henrique; Rico, Eduardo P.; Pinto, Charles B.; Rosemberg, Denis B.; Dutra-Filho, Carlos S.; Dias, Renato D.; Oliveira, Diogo L.; T. Rocha, João Batista; Souza, Diogo O.

    2016-01-01

    The increase in brain levels of chelatable zinc (Zn) in dysfunctions involving oxygen deprivation has stimulated the treatment with Zn chelators, such as diethyldithiocarbamate (DEDTC). However, DEDTC is a redox-active compound and it should be better evaluated during hypoxia. We use the hypoxia model in zebrafish to evaluate DEDTC effects. The exploratory behavior, chelatable Zn content, activities of mitochondrial dehydrogenases, reactive species levels (nitric oxide, superoxide anion, hydroxyl radical scavenger capacity) and cellular antioxidants (sulfhydryl, superoxide dismutase) of zebrafish brain were assessed after recovery, with or without 0.2 mM DEDTC. The increased brain levels of chelatable Zn induced by hypoxia were mitigated by DEDTC. However, the novel tank task indicated that DEDTC did further enhance the exploratory deficit caused by hypoxia. Furthermore, these behavioral impairments caused by DEDTC were more associated with a negative action on mitochondrial activity and brain oxidative balance. Thus, due to apparent pro-oxidant action of DEDTC, our data do not support its use for neuroprotection in neuropathologies involving oxygen deprivation. PMID:26854133

  9. Cytochrome c as a Potentially Clinical Useful Marker of Mitochondrial and Cellular Damage

    PubMed Central

    Eleftheriadis, Theodoros; Pissas, Georgios; Liakopoulos, Vassilios; Stefanidis, Ioannis

    2016-01-01

    Mitochondria are evolutionary endosymbionts derived from bacteria. Thus, they bear molecules, such as mitochondrial DNA (mtDNA) that contains CpG DNA repeats and N-formyl peptides (FPs), found in bacteria. Upon cell necrosis or apoptosis, these molecules are released into the interstitial space and the circulation and recognized by the immune cells through the same receptors that recognize pathogen-associated molecular patterns, leading to inflammation. Other mitochondrial molecules are not of bacterial origin, but they may serve as danger-associated molecular patterns (DAMPs) when due to cell injury are translocated into inappropriate compartments. There they are recognized by pattern recognition receptors of the immune cells. Cytochrome c is such a molecule. In this review, experimental and clinical data are presented that confirms cytochrome c release into the extracellular space in pathological conditions characterized by cell death. This indicates that serum cytochrome c, which can be easily measured, may be a clinically useful marker for diagnosing and assessing the severity of such pathological entities. Reasonably, detection of high cytochrome c level into the circulation means release of various other molecules that serves as DAMPs when found extracellularly, the mtDNA and FPs included. Finally, because the release of this universally found compound into the extracellular space makes cytochrome c an ideal molecule to play the role of a DAMP per se, the available experimental and clinical data that support such a role are provided. PMID:27489552

  10. Mitochondrial Damage and Apoptosis Induced by Adenosine Deaminase Inhibition and Deoxyadenosine in Human Neuroblastoma Cell Lines.

    PubMed

    Garcia-Gil, Mercedes; Tozzi, Maria Grazia; Balestri, Francesco; Colombaioni, Laura; Camici, Marcella

    2016-07-01

    The treatment with deoxycoformycin, a strong adenosine deaminase inhibitor, in combination with deoxyadenosine, causes apoptotic cell death of two human neuroblastoma cell lines, SH-SY5Y and LAN5. Herein we demonstrate that, in SH-SY5Y cells, this combination rapidly decreases mitochondrial reactive oxygen species and, in parallel, increases mitochondrial mass, while, later, induces nuclear fragmentation, and activation of caspase-8, -9, and -3. In previous papers we have shown that a human astrocytoma cell line, subjected to the same treatment, undergoes apoptotic death as well. Therefore, both astrocytoma and neuroblastoma cell lines undergo apoptotic death following the combined treatment with deoxycoformycin and deoxyadenosine, but several differences have been found in the mode of action, possibly reflecting a different functional and metabolic profile of the two cell lines. Overall this work indicates that the neuroblastoma cell lines, like the line of astrocytic origin, are very sensitive to purine metabolism perturbation thus suggesting new therapeutic approaches to nervous system tumors. J. Cell. Biochem. 117: 1671-1679, 2016. © 2015 Wiley Periodicals, Inc. PMID:26659614

  11. Liver ultrastructural morphology and mitochondrial DNA levels in HIV/hepatitis C virus coinfection: no evidence of mitochondrial damage with highly active antiretroviral therapy.

    PubMed

    Matsukura, Motoi; Chu, Fanny F S; Au, May; Lu, Helen; Chen, Jennifer; Rietkerk, Sonja; Barrios, Rolando; Farley, John D; Montaner, Julio S; Montessori, Valentina C; Walker, David C; Côté, Hélène C F

    2008-06-19

    Liver mitochondrial toxicity is a concern, particularly in HIV/hepatitis C virus (HCV) coinfection. Liver biopsies from HIV/HCV co-infected patients, 14 ON-highly active antiretroviral therapy (HAART) and nine OFF-HAART, were assessed by electron microscopy quantitative morphometric analyses. Hepatocytes tended to be larger ON-HAART than OFF-HAART (P = 0.05), but mitochondrial volume, cristae density, lipid volume, mitochondrial DNA and RNA levels were similar. We found no evidence of increased mitochondrial toxicity in individuals currently on HAART, suggesting that concomitant HAART should not delay HCV therapy. PMID:18525271

  12. Persistent DNA damage caused by low levels of mitomycin C induces irreversible cell senescence.

    PubMed

    McKenna, Elise; Traganos, Frank; Zhao, Hong; Darzynkiewicz, Zbigniew

    2012-08-15

    Mutations of oncogenes and tumor suppressor genes which activate mTOR through several downstream signaling pathways are common to cancer. Activation of mTOR when combined with inhibition of cell cycle progression or DNA replication stress has previously been shown to promote cell senescence. In the present study, we examined the conditions under which human non-small cell lung carcinoma A549 cells can undergo senescence when treated with the DNA alkylating agent mitomycin C (MMC). While exposure of A549 cells to 0.1 or 0.5 µg/ml of MMC led to their arrest in S phase of the cell cycle and subsequent apoptosis, exposure to 0.01 or 0.02 µg/ml for 6 d resulted in induction of cell senescence and near total (0.01 µg/ml) or total (0.02 µg/ml) elimination of their reproductive potential. During exposure to these low concentrations of MMC, the cells demonstrated evidence of DNA replication stress manifested by expression of γH2AX, p21 (WAF1) and a very low level of EdU incorporation into DNA. The data are consistent with the notion that enduring DNA replication stress in cells known to have activated oncogenes leads to their senescence. It is reasonable to expect that tumors having constitutive activation of oncogenes triggering mTOR signaling may be particularly predisposed to undergoing senescence following prolonged treatment with low doses of DNA damaging drugs. PMID:22871735

  13. Persistent and heritable structural damage induced in heterochromatic DNA from rat liver by N-nitrosodimethylamine

    SciTech Connect

    Ward, E.J.; Stewart, B.W.

    1987-03-24

    Analysis, by benzoylated DEAE-cellulose chromatography, has been made of structural change in eu- and heterochromatic DNA from rat liver following administration of the carcinogen N-nitrosodimethylamine. Either hepatic DNA was prelabeled with (/sup 3/H)thymidine administered 2-3 weeks before injection of the carcinogen or the labeled precursor was given during regenerative hyperplasia in rats treated earlier with N-nitrosodimethylamine. Following phenol extraction of either whole liver homogenate or nuclease-fractionated eu- and heterochromatin, carcinogen-modified DNA was examined by stepwise or caffeine gradient elution from benzoylated DEAE-cellulose. In whole DNA, nitrosamine-induced single-stranded character was maximal 4-24 h after treatment, declining rapidly thereafter; gradient elution of these DNA preparations also provided short-term evidence of structural change. Caffeine gradient chromatography suggested short-term nitrosamine-induced structural change in euchromatic DNA, while increased binding of heterochromatic DNA was evident for up to 3 months after carcinogen treatment. Preparations of newly synthesized heterochromatic DNA from animals subjected to hepatectomy up to 2 months after carcinogen treatment provided evidence of heritable structural damage. Carcinogen-induced binding of heterochromatic DNA to benzoylated DEAE-cellulose was indicative of specific structural lesions whose affinity equalled that of single-stranded DNA up to 1.0 kilobase in length. The data suggest that structural lesions in heterochromatin, which may be a consequence of incomplete repair, are preferentially degraded by endogenous nuclease(s).

  14. Redox regulation of protein misfolding, mitochondrial dysfunction, synaptic damage, and cell death in neurodegenerative diseases

    PubMed Central

    Nakamura, Tomohiro; Cho, Dong-Hyung; Lipton, Stuart A.

    2012-01-01

    The loss or injury of neurons associated with oxidative and nitrosative redox stress plays an important role in the onset of various neurodegenerative diseases. Specifically, nitric oxide (NO), can affect neuronal survival through a process called S-nitrosylation, by which the NO group undergoes a redox reaction with specific protein thiols. This in turn can lead to the accumulation of misfolded proteins, which generally form aggregates in Alzheimer’s, Parkinson’s, and other neurodegenerative diseases. Evidence suggests that S-nitrosylation can also impair mitochondrial function and lead to excessive fission of mitochondria and consequent bioenergetic compromise via effects on the activity of the fission protein dynamin-related protein 1 (Drp1). This insult leads to synaptic dysfunction and loss. Additionally, high levels of NO can S-nitrosylate a number of aberrant targets involved in neuronal survival pathways, including the antiapoptotic protein XIAP, inhibiting its ability to prevent apoptosis. PMID:22771760

  15. Redox modulation by S-nitrosylation contributes to protein misfolding, mitochondrial dynamics, and neuronal synaptic damage in neurodegenerative diseases

    PubMed Central

    Nakamura, T; Lipton, S A

    2011-01-01

    The pathological processes of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases engender synaptic and neuronal cell damage. While mild oxidative and nitrosative (nitric oxide (NO)-related) stress mediates normal neuronal signaling, excessive accumulation of these free radicals is linked to neuronal cell injury or death. In neurons, N-methyl--aspartate (NMDA) receptor (NMDAR) activation and subsequent Ca2+ influx can induce the generation of NO via neuronal NO synthase. Emerging evidence has demonstrated that S-nitrosylation, representing covalent reaction of an NO group with a critical protein thiol, mediates the vast majority of NO signaling. Analogous to phosphorylation and other posttranslational modifications, S-nitrosylation can regulate the biological activity of many proteins. Here, we discuss recent studies that implicate neuropathogenic roles of S-nitrosylation in protein misfolding, mitochondrial dysfunction, synaptic injury, and eventual neuronal loss. Among a growing number of S-nitrosylated proteins that contribute to disease pathogenesis, in this review we focus on S-nitrosylated protein-disulfide isomerase (forming SNO-PDI) and dynamin-related protein 1 (forming SNO-Drp1). Furthermore, we describe drugs, such as memantine and newer derivatives of this compound that can prevent both hyperactivation of extrasynaptic NMDARs as well as downstream pathways that lead to nitrosative stress, synaptic damage, and neuronal loss. PMID:21597461

  16. Redox modulation by S-nitrosylation contributes to protein misfolding, mitochondrial dynamics, and neuronal synaptic damage in neurodegenerative diseases.

    PubMed

    Nakamura, T; Lipton, S A

    2011-09-01

    The pathological processes of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases engender synaptic and neuronal cell damage. While mild oxidative and nitrosative (nitric oxide (NO)-related) stress mediates normal neuronal signaling, excessive accumulation of these free radicals is linked to neuronal cell injury or death. In neurons, N-methyl-D-aspartate (NMDA) receptor (NMDAR) activation and subsequent Ca(2+) influx can induce the generation of NO via neuronal NO synthase. Emerging evidence has demonstrated that S-nitrosylation, representing covalent reaction of an NO group with a critical protein thiol, mediates the vast majority of NO signaling. Analogous to phosphorylation and other posttranslational modifications, S-nitrosylation can regulate the biological activity of many proteins. Here, we discuss recent studies that implicate neuropathogenic roles of S-nitrosylation in protein misfolding, mitochondrial dysfunction, synaptic injury, and eventual neuronal loss. Among a growing number of S-nitrosylated proteins that contribute to disease pathogenesis, in this review we focus on S-nitrosylated protein-disulfide isomerase (forming SNO-PDI) and dynamin-related protein 1 (forming SNO-Drp1). Furthermore, we describe drugs, such as memantine and newer derivatives of this compound that can prevent both hyperactivation of extrasynaptic NMDARs as well as downstream pathways that lead to nitrosative stress, synaptic damage, and neuronal loss. PMID:21597461

  17. Cytosolic DNA triggers mitochondrial apoptosis via DNA damage signaling proteins independently of AIM2 and RNA polymerase III.

    PubMed

    Wenzel, Michael; Wunderlich, Michael; Besch, Robert; Poeck, Hendrik; Willms, Simone; Schwantes, Astrid; Kremer, Melanie; Sutter, Gerd; Endres, Stefan; Schmidt, Andreas; Rothenfusser, Simon

    2012-01-01

    A key host response to limit microbial spread is the induction of cell death when foreign nucleic acids are sensed within infected cells. In mouse macrophages, transfected DNA or infection with modified vaccinia virus Ankara (MVA) can trigger cell death via the absent in melanoma 2 (AIM2) inflammasome. In this article, we show that nonmyeloid human cell types lacking a functional AIM2 inflammasome still die in response to cytosolic delivery of different DNAs or infection with MVA. This cell death induced by foreign DNA is independent of caspase-8 and carries features of mitochondrial apoptosis: dependence on BAX, APAF-1, and caspase-9. Although it does not require the IFN pathway known to be triggered by infection with MVA or transfected DNA via polymerase III and retinoid acid-induced gene I-like helicases, it shows a strong dependence on components of the DNA damage signaling pathway: cytosolic delivery of DNA or infection with MVA leads to phosphorylation of p53 (serines 15 and 46) and autophosphorylation of ataxia telangiectasia mutated (ATM); depleting p53 or ATM with small interfering RNA or inhibiting the ATM/ATM-related kinase family by caffeine strongly reduces apoptosis. Taken together, our findings suggest that a pathway activating DNA damage signaling plays an important independent role in detecting intracellular foreign DNA, thereby complementing the induction of IFN and activation of the AIM2 inflammasome. PMID:22140256

  18. Decreased in vitro fertility in male rats exposed to fluoride-induced oxidative stress damage and mitochondrial transmembrane potential loss

    SciTech Connect

    Izquierdo-Vega, Jeannett A.; Sanchez-Gutierrez, Manuel; Razo, Luz Maria del

    2008-08-01

    Fluorosis, caused by drinking water contamination with inorganic fluoride, is a public health problem in many areas around the world. The aim of the study was to evaluate the effect of environmentally relevant doses of fluoride on in vitro fertilization (IVF) capacity of spermatozoa, and its relationship to spermatozoa mitochondrial transmembrane potential ({delta}{psi}{sub m}). Male Wistar rats were administered at 5 mg fluoride/kg body mass/24 h, or deionized water orally for 8 weeks. We evaluated several spermatozoa parameters in treated and untreated rats: i) standard quality analysis, ii) superoxide dismutase (SOD) activity, iii) the generation of superoxide anion (O{sub 2}{sup {center_dot}}{sup -}), iv) lipid peroxidation concentration, v) ultrastructural analyses of spermatozoa using transmission electron microscopy, vi) {delta}{psi}{sub m}, vii) acrosome reaction, and viii) IVF capability. Spermatozoa from fluoride-treated rats exhibited a significant decrease in SOD activity ({approx} 33%), accompanied with a significant increase in the generation of O{sub 2}{sup {center_dot}} ({approx} 40%), a significant decrease in {delta}{psi}{sub m} ({approx} 33%), and a significant increase in lipid peroxidation concentration ({approx} 50%), relative to spermatozoa from the control group. Consistent with this finding, spermatozoa from fluoride-treated rats exhibited altered plasmatic membrane. In addition, the percentage of fluoride-treated spermatozoa capable of undergoing the acrosome reaction was decreased relative to control spermatozoa (34 vs. 55%), while the percentage fluoride-treated spermatozoa capable of oocyte fertilization was also significantly lower than the control group (13 vs. 71%). These observations suggest that subchronic exposure to fluoride causes oxidative stress damage and loss of mitochondrial transmembrane potential, resulting in reduced fertility.

  19. Alternariol induce toxicity via cell death and mitochondrial damage on Caco-2 cells.

    PubMed

    Fernández-Blanco, Celia; Juan-García, Ana; Juan, Cristina; Font, Guillermina; Ruiz, Maria-Jose

    2016-02-01

    Alternariol (AOH), a mycotoxin produced by Alternaria sp, appears as food contaminant in fruit, vegetables and cereal products. Its toxicity has been demonstrated, but the mechanisms involved have not been elucidated yet. In this study, the pathways triggered by AOH and degradation products generated on Caco-2 cells were evaluated. Cells were exposed to AOH sub-cytotoxic concentrations of 15, 30 and 60 μM. Cell cycle disruption, the induction of apoptosis/necrosis and changes in mitochondrial membrane potential (Δψm) after 24 and 48 h was asses by flow cytometry. Also, AOH and its degradation products were evaluated after 24 and 48 h by high-performance liquid chromatography with tandem mass spectrometric (LC-MS/MS) to detect and quantify its levels. Cell cycle was significantly decreased at G1 phase and increased at S and G2/M phase at the time of exposure. AOH induced necrosis, apoptosis/necrosis and loss of Δψm in a dose and time-dependent manner. The concentrations of AOH quantified in the culture media exposed to AOH decreased as the exposure time was increased. In conclusion, AOH caused cytotoxic effects supported by blocking cell cycle, decreasing cell proliferation and increasing apoptosis/necrosis cells. PMID:26683312

  20. Role of chemokines and their receptors in viral persistence and liver damage during chronic hepatitis C virus infection.

    PubMed

    Larrubia, Juan R; Benito-Martínez, Selma; Calvino, Miryam; Sanz-de-Villalobos, Eduardo; Parra-Cid, Trinidad

    2008-12-21

    Chemokines produced in the liver during hepatitis C virus (HCV) infection induce migration of activated T cells from the periphery to infected parenchyma. The milieu of chemokines secreted by infected hepatocytes is predominantly associated with the T-helper cell/Tc1 T cell (Th1/Tc1) response. These chemokines consist of CCL3 (macrophage inflammatory protein-1 alpha; MIP-1 alpha), CCL4 (MIP-1 beta), CCL5 (regulated on activation normal T cell expressed and secreted; RANTES), CXCL10 (interferon-gamma-inducible protein-10; IP-10), CXCL11 (interferon-inducible T-cell alpha chemoattractant; I-TAC), and CXCL9 (monokine induced by interferon gamma; Mig) and they recruit T cells expressing either CCR5 or CXCR3 chemokine receptors. Intrahepatic and peripheral blood levels of these chemokines are increased during chronic hepatitis C. The interaction between chemokines and their receptors is essential in recruiting HCV-specific T cells to control the infection. When the adaptive immune response fails in this task, non-specific T cells without the capacity to control the infection are also recruited to the liver, and these are ultimately responsible for the persistent hepatic damage. The modulation of chemokine receptor expression and chemokine secretion could be a viral escape mechanism to avoid specific T cell migration to the liver during the early phase of infection, and to maintain liver viability during the chronic phase, by impairing non-specific T cell migration. Some chemokines and their receptors correlate with liver damage, and CXCL10 (IP-10) and CXCR3 levels have shown a clinical utility as predictors of treatment response outcome. The regulation of chemokines and their receptors could be a future potential therapeutic target to decrease liver inflammation and to increase specific T cell migration to the infected liver. PMID:19084927

  1. Depletion of the cellular antioxidant system contributes to tenofovir disoproxil fumarate - induced mitochondrial damage and increased oxido-nitrosative stress in the kidney

    PubMed Central

    2013-01-01

    Background Nephrotoxicity is a dose limiting side effect of tenofovir, a reverse transcriptase inhibitor that is used for the treatment of HIV infection. The mechanism of tenofovir nephrotoxicity is not clear. Tenofovir is specifically toxic to the proximal convoluted tubules and proximal tubular mitochondria are the targets of tenofovir cytotoxicity. Damaged mitochondria are major sources of reactive oxygen species and cellular damage is reported to occur after the antioxidants are depleted. The purpose of the study is to investigate the alterations in cellular antioxidant system in tenofovir induced renal damage using a rat model. Results Chronic tenofovir administration to adult Wistar rats resulted in proximal tubular damage (as evidenced by light microscopy), proximal tubular dysfunction (as shown by Fanconi syndrome and tubular proteinuria), and extensive proximal tubular mitochondrial injury (as revealed by electron microscopy). A 50% increase in protein carbonyl content was observed in the kidneys of TDF treated rats as compared with the control. Reduced glutathione was decreased by 50%. The activity of superoxide dismutase was decreased by 57%, glutathione peroxidase by 45%, and glutathione reductase by 150% as compared with control. Carbonic Anhydrase activity was decreased by 45% in the TDF treated rat kidneys as compared with control. Succinate dehydrogenase activity, an indicator of mitochondrial activity was decreased by 29% in the TDF treated rat kidneys as compared with controls, suggesting mitochondrial dysfunction. Conclusion Tenofovir- induced mitochondrial damage and increased oxidative stress in the rat kidneys may be due to depletion of the antioxidant system particularly, the glutathione dependent system and MnSOD. PMID:23957306

  2. Effects of benzo[a]pyrene on mitochondrial and nuclear DNA damage in Atlantic killifish (Fundulus heteroclitus) from a creosote-contaminated and reference site

    PubMed Central

    Jung, Dawoon; Cho, Youngeun; Collins, Leonard B.; Swenberg, James A.; Di Giulio, Richard T.

    2009-01-01

    Benzo[a]pyrene (BaP) is a known genotoxicant that affects both mitochondrial and nuclear DNA (mtDNA, nDNA). Here, we examined mtDNA and nDNA damage in the Atlantic killifish (Fundulus heteroclitus) from a highly contaminated Superfund site (Elizabeth River, VA, USA) and from a reference site (King’s Creek, VA, USA) that were dosed with 10 mg/kg BaP. Using the long amplicon quantitative PCR technique, we observed similar increases in mitochondrial and nuclear DNA damage in King’s Creek fish treated with BaP. Killifish from the Elizabeth River showed high levels of basal nDNA and mtDNA damage compared to fish from the reference site, but the level of damage induced due to BaP treatment was much lower in Elizabeth River killifish compared to King’s Creek fish. Laboratory-reared offspring from both populations showed increased BaP-induced damage in mtDNA, relative to nDNA. Similar to the adult experiment, the Elizabeth River larvae had higher levels of basal DNA damage than those from the reference site, but were less impacted by BaP exposure. Measurements of oxidative DNA damage (8-oxo-deoxyguanine by LC-MS/MS) showed no differences among treatment groups, suggesting that the majority of DNA damage is from covalent binding of BaP metabolites to DNA. This study shows for the first time that mitochondria can be an important target of BaP toxicity in fish, indicating that BaP exposures could have important energetic consequences. Results also suggest that multi-generational exposures in the wild may lead to adaptations that dampen DNA damage arising from BaP exposure. PMID:19726093

  3. Nrf2-ARE Activator Carnosic Acid Decreases Mitochondrial Dysfunction, Oxidative Damage and Neuronal Cytoskeletal Degradation Following Traumatic Brain Injury in Mice

    PubMed Central

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

    2014-01-01

    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 (ARE) 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 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 minutes post-TBI reduced cortical lipid peroxidation, protein nitration, and cytoskeletal breakdown markers in a dose-dependent manner at 48 hours 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 8 hours 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. PMID:25432068

  4. Repeated ovarian stimulations induce oxidative damage and mitochondrial DNA mutations in mouse ovaries.

    PubMed

    Chao, Hsiang-Tai; Lee, Shu-Yu; Lee, Horng-Mo; Liao, Tien-Ling; Wei, Yau-Huei; Kao, Shu-Huei

    2005-05-01

    Superovulation by injection of exogenous gonadotropin is the elementary method to produce in vivo-derived embryos for embryo transfer in women. Increased oocyte aneuploidy, embryo mortality, fetal growth retardation, and congenital abnormalities have been studied at higher-dose stimulations. Ovarian and oocyte biological aging possibly may have adverse implications for human oocyte competence with repeated hyperstimulation. In this study, we found that reduced competence for the human oocyte has been associated with degenerative embryo upsurge during embryo culture and failure to develop into the blastocyst stage in the three, four, five, and six stimulation cycles. On the other hand, the numbers of ovulated oocytes were decreased in the groups with more ovarian stimulation. More aggregated mitochondria were found in the cytoplasm of the repetitively stimulated embryos. Higher amounts of oxidative damage including 8-OH-dG, lipoperoxides, and carbonyl proteins were also revealed in the ovaries with more cycle numbers of ovarian stimulation. Higher proportions of mtDNA mutations were also found. The detected molecular size of the mutated band was approximately 675 bp. Increased amounts of carbonyl proteins were also revealed after repeated stimulation. An understanding of the relationship between oocyte competence and ovarian responses to stimulation in the mouse may provide insights into the origin of oocyte defects and the biology of ooplasmic aging that could be of clinical relevance in the diagnosis and treatment of human infertility. PMID:15965057

  5. Vinca alkaloids cause aberrant ROS-mediated JNK activation, Mcl-1 downregulation, DNA damage, mitochondrial dysfunction, and apoptosis in lung adenocarcinoma cells.

    PubMed

    Chiu, Wei-Hsin; Luo, Sheng-Jei; Chen, Chia-Ling; Cheng, Jai-Hong; Hsieh, Chia-Yuan; Wang, Chi-Yun; Huang, Wei-Ching; Su, Wu-Chou; Lin, Chiou-Feng

    2012-05-01

    Vinca alkaloids are clinically used to inhibit the growth of malignancy by interfering with microtubule polymerization. The purpose of this study was to identify the molecular mechanisms underlying growth inhibition as well as apoptosis in vinca alkaloid-treated lung adenocarcinoma cells. Consistent with nocodazole, treatment with vinorelbine (VNR) caused mitotic prometaphase arrest in a time-dependent manner, accompanied by cell apoptosis, dependent on both dose and time. VNR sequentially induced mitochondrial transmembrane potential (MTP) loss and caspase-dependent apoptosis following myeloid cell leukemia (Mcl) 1 downregulation. Prolonged activation of c-Jun N-terminal kinase (JNK) was required for vinca alkaloid- and nocodazole-induced apoptosis but not cell cycle arrest. Vinca alkaloids and nocodazole caused glutathione/reactive oxygen species (ROS) imbalance, and inhibiting ROS prevented prolonged JNK activation, decreased Mcl-1 levels, MTP loss, and apoptosis. Notably, cell size and granularity were enlarged in stimulated cells; unexpectedly, many ROS-producing mitochondria were accumulated followed by aberrant JNK-mediated mitochondrial dysfunction. Unlike cisplatin, which causes DNA damage in each phase of the cell cycle, VNR and nocodazole induced aberrant JNK-regulated DNA damage in prometaphase; however, inhibiting ATM (ataxia telangiectasia, mutated) and ATR (ATM and Rad3-related) did not reverse mitotic arrest or apoptosis. These results demonstrate an essential role of ROS in vinca alkaloid-induced aberrant JNK-mediated Mcl-1 downregulation and DNA damage followed by mitochondrial dysfunction-related apoptosis but not mitotic arrest. PMID:22285910

  6. Deficiency of methionine sulfoxide reductase A causes cellular dysfunction and mitochondrial damage in cardiac myocytes under physical and oxidative stresses

    SciTech Connect

    Nan, Changlong; Li, Yuejin; Jean-Charles, Pierre-Yves; Chen, Guozhen; Kreymerman, Alexander; Prentice, Howard; Weissbach, Herbert; Huang, Xupei

    2010-11-26

    Research highlights: {yields} Deficiency of MsrA in the heart renders myocardial cells more sensitive to oxidative stress. {yields} Mitochondrial damage happens in the heart lacking MsrA. {yields} More protein oxidation in myocardial cells lacking MsrA. {yields} MsrA protects the heart against oxidative stress. -- Abstract: Methionine sulfoxide reductase A (MsrA) is an enzyme that reverses oxidation of methionine in proteins. Using a MsrA gene knockout (MsrA{sup -/-}) mouse model, we have investigated the role of MsrA in the heart. Our data indicate that cellular contractility and cardiac function are not significantly changed in MsrA{sup -/-} mice if the hearts are not stressed. However, the cellular contractility, when stressed using a higher stimulation frequency (2 Hz), is significantly reduced in MsrA{sup -/-} cardiac myocytes. MsrA{sup -/-} cardiac myocytes also show a significant decrease in contractility after oxidative stress using H{sub 2}O{sub 2}. Corresponding changes in Ca{sup 2+} transients are observed in MsrA{sup -/-} cardiomyocytes treated with 2 Hz stimulation or with H{sub 2}O{sub 2}. Electron microscope analyses reveal a dramatic morphological change of mitochondria in MsrA{sup -/-} mouse hearts. Further biochemical measurements indicate that protein oxidation levels in MsrA{sup -/-} mouse hearts are significantly higher than those in wild type controls. Our study demonstrates that the lack of MsrA in cardiac myocytes reduces myocardial cell's capability against stress stimulations resulting in a cellular dysfunction in the heart.

  7. Dermal γδ T-Cells Can Be Activated by Mitochondrial Damage-Associated Molecular Patterns

    PubMed Central

    Schwacha, Martin G.; Rani, Meenakshi; Nicholson, Susannah E.; Lewis, Aaron M.; Holloway, Travis L.; Sordo, Salvador; Cap, Andrew P.

    2016-01-01

    Background Gamma delta T-cells have been shown to be important to the early immunoinflammatory response to injury, independent of infection. This unique T-cell population acts to regulate cell trafficking and the release of cytokines and growth factors. We propose this sterile inflammatory response is in part associated with damage associated molecular patterns (DAMPs) generated by major injury, such as burn, and mediated via toll-like receptors (TLRs). It is unknown whether DAMPs can activate resident γδ T-cells that reside in skin. Methods Gamma delta T-cells were isolated from the skin of male C57BL/6 mice by enzymatic digestion. Mitochondrial DAMPs (MTDs) were generated from mitochondria isolated from mouse livers by sonication and centrifugation. Dermal γδ T-cells were incubated with MTDs (0–500 μg/ml) for 24 hr and cells and supernatants were collected for analysis. Results MTDs activated dermal γδ T-cells, as evidenced by increased TLR2 and TLR4 expression following in vitro exposure. MTDs also induced the production of inflammatory cytokines (IL-1β, IL-6), and growth factors (PDGF and VEGF) by γδ T-cells. Conclusions These findings herein support the concept that MTDs released after tissue/cellular injury are capable of activating dermal γδ T-cells. We propose that the activation of this unique T-cell population is central in the initiation of sterile inflammation and also contributes to the subsequent healing processes. PMID:27403524

  8. The simultaneous detection of mitochondrial DNA damage from sun-exposed skin of three whale species and its association with UV-induced microscopic lesions and apoptosis.

    PubMed

    Bowman, Amy; Martinez-Levasseur, Laura M; Acevedo-Whitehouse, Karina; Gendron, Diane; Birch-Machin, Mark A

    2013-07-01

    Due to life history and physiological constraints, cetaceans (whales) are unable to avoid prolonged exposure to external environmental insults, such as solar ultraviolet radiation (UV). The majority of studies on the effects of UV on skin are restricted to humans and laboratory animals, but it is important to develop tools to understand the effects of UV damage on large mammals such as whales, as these animals are long-lived and widely distributed, and can reflect the effects of UV across a large geographical range. We and others have used mitochondrial DNA (mtDNA) as a reliable marker of UV-induced damage particularly in human skin. UV-induced mtDNA strand breaks or lesions accumulate throughout the lifespan of an individual, thus constituting an excellent biomarker for cumulative exposure. Based on our previous studies in human skin, we have developed for the first time in the literature a quantitative real-time PCR methodology to detect and quantify mtDNA lesions in skin from sun-blistered whales. Furthermore the methodology allows for simultaneous detection of mtDNA damage in different species. Therefore using 44 epidermal mtDNA samples collected from 15 blue whales, 10 fin whales, and 19 sperm whales from the Gulf of California, Mexico, we quantified damage across 4.3 kilobases, a large region of the ~16,400 base pair whale mitochondrial genome. The results show a range of mtDNA damage in the skin of the three different whale species. This previously unreported observation was correlated with apoptotic damage and microscopic lesions, both of which are markers of UV-induced damage. As is the case in human studies, this suggests the potential use of mtDNA as a biomarker for measuring the effect of cumulative UV exposure in whales and may provide a platform to help understand the effects of changing global environmental conditions. PMID:23583579

  9. Mitochondrial protein quality control in health and disease

    PubMed Central

    Baker, Michael J; Palmer, Catherine S; Stojanovski, Diana

    2014-01-01

    Progressive mitochondrial dysfunction is linked with the onset of many age-related pathologies and neurological disorders. Mitochondrial damage can come in many forms and be induced by a variety of cellular insults. To preserve organelle function during biogenesis or times of stress, multiple surveillance systems work to ensure the persistence of a functional mitochondrial network. This review provides an overview of these processes, which collectively contribute to the maintenance of a healthy mitochondrial population, which is critical for cell physiology and survival. 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:24117041

  10. A role for MHR1, a gene required for mitochondrial genetic recombination, in the repair of damage spontaneously introduced in yeast mtDNA

    PubMed Central

    Ling, Feng; Morioka, Hiroshi; Ohtsuka, Eiko; Shibata, Takehiko

    2000-01-01

    A nuclear recessive mutant in Saccharomyces cerevisiae, mhr1-1, is defective in mitochondrial genetic recombination at 30°C and shows extensive vegetative petite induction by UV irradiation at 30°C or when cultivated at a higher temperature (37°C). It has been postulated that mitochondrial DNA (mtDNA) is oxidatively damaged by by-products of oxidative respiration. Since genetic recombination plays a critical role in DNA repair in various organisms, we tested the possibility that MHR1 plays a role in the repair of oxidatively damaged mtDNA using an enzyme assay. mtDNA isolated from cells grown under standard (aerobic) conditions contained a much higher level of DNA lesions compared with mtDNA isolated from anaerobically grown cells. Soon after a temperature shift from 30 to 37°C the number of mtDNA lesions increased 2-fold in mhr1-1 mutant cells but not in MHR1 cells. Malonic acid, which decreased the oxidative stress in mitochondria, partially suppressed both petite induction and the temperature-induced increase in the amount of mtDNA damage in mhr1-1 cells at 37°C. Thus, functional mitochondria require active MHR1, which keeps the extent of spontaneous oxidative damage in mtDNA within a tolerable level. These observations are consistent with MHR1 having a possible role in mtDNA repair. PMID:11121487

  11. CTRP9 induces mitochondrial biogenesis and protects high glucose-induced endothelial oxidative damage via AdipoR1 -SIRT1- PGC-1α activation.

    PubMed

    Cheng, Liang; Li, Bin; Chen, Xu; Su, Jie; Wang, Hongbing; Yu, Shiqiang; Zheng, Qijun

    2016-09-01

    Vascular lesions caused by endothelial dysfunction are the most common and serious complication of diabetes. The vasoactive potency of CTRP9 has been reported in our previous study via nitric oxide (NO) production. However, the effect of CTRP9 on vascular endothelial cells remains unknown. This study aimed to investigate the protection role of CTRP9 in the primary aortic vascular endothelial cells and HAECs under high-glucose condition. We found that the aortic vascular endothelial cells isolated from mice fed with a high fat diet generated more ROS production than normal cells, along with decreased mitochondrial biogenesis, which was also found in HAECs treated with high glucose. However, the treatment of CTPR9 significantly reduced ROS production and increased the activities of endogenous antioxidant enzymes, the expression of PGC-1α, NRF1, TFAM, ATP5A1 and SIRT1, and the activity of cytochrome c oxidase, indicating an induction of mitochondrial biogenesis. Furthermore, silencing the expression of SIRT1 in HAECs impeded the effect of CTRP9 on mitochondrial biogenesis, while silencing the expression of AdipoR1 in HAECs reversed the expression of SIRT1 and PGC-1α. Based on these findings, this study showed that CTRP9 might induce mitochondrial biogenesis and protect high glucose-induced endothelial oxidative damage via AdipoR1-SIRT1-PGC-1α signaling pathway. PMID:27349872

  12. Assessment of Newly Synthesized Mitochondrial DNA Using BrdU Labeling in Primary Neurons from Alzheimer’s Disease Mice: Implications for Impaired Mitochondrial Biogenesis and Synaptic Damage

    PubMed Central

    Calkins, Marcus J.; Reddy, P. Hemachandra

    2011-01-01

    The purpose our study was to assess mitochondrial biogenesis and distribution in murine primary neurons. Using 5-bromo-2-deoxyuridie (BrdU) incorporation and primary neurons, we studied the mitochondrial biogenesis and mitochondrial distribution in hippocampal neurons from amyloid beta precursor protein (AβPP) transgenic mice and wild-type (WT) neurons treated with oxidative stressors, rotenone and H2O2. We found that after 20 hr of labeling, BrdU incorporation was specific to porin-positive mitochondria. The proportion of mitochondrial area that labeled with BrdU was 40.3 ± 6.3% at 20 hr. The number of mitochondria with newly synthesized DNA was higher in AβPP neuronal cell bodies than in the cell bodies of WT neurons (AβPP, 45.23 ± 2.67 BrdU-positive/cell body; WT, 32.92 ± 2.49 BrdU-positive/cell body; p = 0.005). In neurites, the number of BrdU-positive mitochondria decreased in AβPP cultures compared to WT neurons (AβPP, 0.105 ± 0.008 BrdU-positive/μm neurite; WT, 0.220 ± 0.036 BrdU-positive−/−μm neurite; p = 0.010). Further, BrdU in the cell body increased when neurons were treated with low doses of H2O2 (49.6 ± 2.7 BrdU-positive/cell body, p = 0.0002 compared to untreated cells), while the neurites showed decreased BrdU staining (0.122 ± 0.010 BrdU-positive/μm neurite, p = 0.005 compared to the untreated). BrdU labeling was increased in the cell body under rotenone treatment. Additionally, under rotenone treatment, the content of BrdU labeling decreased in neurites. These findings suggest that Aβ and mitochondrial toxins enhance mitochondrial fragmentation in cell body, and may cause impaired axonal transport of mitochondria leading to synaptic degeneration. PMID:21549836

  13. Assessment of newly synthesized mitochondrial DNA using BrdU labeling in primary neurons from Alzheimer's disease mice: Implications for impaired mitochondrial biogenesis and synaptic damage.

    PubMed

    Calkins, Marcus J; Reddy, P Hemachandra

    2011-09-01

    The purpose of our study was to assess mitochondrial biogenesis and distribution in murine primary neurons. Using 5-bromo-2-deoxyuridine (BrdU) incorporation and primary neurons, we studied the mitochondrial biogenesis and mitochondrial distribution in hippocampal neurons from amyloid beta precursor protein (AβPP) transgenic mice and wild-type (WT) neurons treated with oxidative stressors, rotenone and H(2)O(2). We found that after 20h of labeling, BrdU incorporation was specific to porin-positive mitochondria. The proportion of mitochondrial area labeled with BrdU was 40.3±6.3% at 20h. The number of mitochondria with newly synthesized DNA was higher in AβPP neuronal cell bodies than in the cell bodies of WT neurons (AβPP, 45.23±2.67 BrdU-positive/cell body; WT, 32.92±2.49 BrdU-positive/cell body; p=0.005). In neurites, the number of BrdU-positive mitochondria decreased in AβPP cultures compared to WT neurons (AβPP, 0.105±0.008 BrdU-positive/μm neurite; WT, 0.220±0.036 BrdU-positive/μm neurite; p=0.010). Further, BrdU in the cell body increased when neurons were treated with low doses of H(2)O(2) (49.6±2.7 BrdU-positive/cell body, p=0.0002 compared to untreated cells), while the neurites showed decreased BrdU staining (0.122±0.010 BrdU-positive/μm neurite, p=0.005 compared to the untreated). BrdU labeling was increased in the cell body under rotenone treatment. Additionally, under rotenone treatment, the content of BrdU labeling decreased in neurites. These findings suggest that Aβ and mitochondrial toxins enhance mitochondrial fragmentation in the cell body, and may cause impaired axonal transport of mitochondria leading to synaptic degeneration. PMID:21549836

  14. The autophagy inhibitor chloroquine targets cancer stem cells in triple negative breast cancer by inducing mitochondrial damage and impairing DNA break repair.

    PubMed

    Liang, Diana H; Choi, Dong Soon; Ensor, Joe E; Kaipparettu, Benny A; Bass, Barbara L; Chang, Jenny C

    2016-07-01

    Triple negative breast cancer (TNBC), characterized by an abundance of treatment-resistant breast cancer stem cells (CSCs), has a poorer prognosis than other types of breast cancers. Despite its aggressiveness, no effective targeted therapy exists for TNBC. Here, we demonstrate that CQ effectively targets CSCs via autophagy inhibition, mitochondrial structural damage, and impairment of double-stranded DNA break repair. Electron microscopy demonstrates CQ-induced mitochondrial cristae damage, which leads to mitochondrial membrane depolarization with a significant reduction in the activity of cytochrome c oxidase and accumulation of superoxide and double-stranded DNA breaks. CQ effectively diminishes the TNBC cells' ability to metastasize in vitro and in a TNBC xenograft model. When administered in combination with carboplatin, CQ effectively inhibits carboplatin-induced autophagy. This combination treatment significantly diminishes the expression of DNA repair proteins in CSC subpopulations, resulting in tumor growth reduction in carboplatin-resistant BRCA1 wild-type TNBC orthotopic xenografts. As TNBC's high treatment failure rate has been attributed to enrichment of CSCs, CQ, an autophagy inhibitor with anti-CSC effects, may be an effective adjunct to current TNBC chemotherapy regimens with carboplatin. PMID:27060208

  15. Exposure to Mitochondrial Genotoxins and Dopaminergic Neurodegeneration in Caenorhabditis elegans

    PubMed Central

    Bodhicharla, Rakesh K.; McKeever, Madeline G.; Arrant, Andrew E.; Margillo, Kathleen M.; Ryde, Ian T.; Cyr, Derek D.; Kosmaczewski, Sara G.; Hammarlund, Marc; Meyer, Joel N.

    2014-01-01

    Neurodegeneration has been correlated with mitochondrial DNA (mtDNA) damage and exposure to environmental toxins, but causation is unclear. We investigated the ability of several known environmental genotoxins and neurotoxins to cause mtDNA damage, mtDNA depletion, and neurodegeneration in Caenorhabditis elegans. We found that paraquat, cadmium chloride and aflatoxin B1 caused more mitochondrial than nuclear DNA damage, and paraquat and aflatoxin B1 also caused dopaminergic neurodegeneration. 6-hydroxydopamine (6-OHDA) caused similar levels of mitochondrial and nuclear DNA damage. To further test whether the neurodegeneration could be attributed to the observed mtDNA damage, C. elegans were exposed to repeated low-dose ultraviolet C radiation (UVC) that resulted in persistent mtDNA damage; this exposure also resulted in dopaminergic neurodegeneration. Damage to GABAergic neurons and pharyngeal muscle cells was not detected. We also found that fasting at the first larval stage was protective in dopaminergic neurons against 6-OHDA-induced neurodegeneration. Finally, we found that dopaminergic neurons in C. elegans are capable of regeneration after laser surgery. Our findings are consistent with a causal role for mitochondrial DNA damage in neurodegeneration, but also support non mtDNA-mediated mechanisms. PMID:25486066

  16. Cyclosporine A-induced apoptosis in renal tubular cells is related to oxidative damage and mitochondrial fission.

    PubMed

    de Arriba, Gabriel; Calvino, Miryam; Benito, Selma; Parra, Trinidad

    2013-03-27

    Cyclosporine A (CsA) nephrotoxicity has been linked to reactive oxygen species (ROS) production in renal cells. We have demonstrated that the antioxidant Vitamin E (Vit E) abolished renal toxicity in vivo and in vitro models. As one of the main sources of intracellular ROS are mitochondria, we studied the effects of CsA on several mitochondrial functions in LLC-PK1 cells. CsA induced ROS synthesis and decreased reduced glutathione (GSH). The drug decreased mitochondrial membrane potential (ΔΨm) and induced physiological modifications in both the inner (IMM) and the outer mitochondrial membranes (OMM). In the IMM, CsA provoked mitochondrial permeability transition pores (MPTP) and cytochrome c was liberated into the intermembrane space. CsA also induced pore formation in the OMM, allowing that intermembrane space contents can reach cytosol. Furthermore, CsA altered the mitochondrial dynamics, inducing an increase in mitochondrial fission; CsA increased the expression of dynamin related protein 1 (Drp1) that contributes to mitochondrial fission, and decreased the expression of mitofusin 2 (Mfn2) and optic atrophy protein 1 (Opa1), proteins involved in the fusion process. All these phenomena were related to apoptosis. These effects were inhibited when cells were treated with the antioxidant Vit E suggesting that they were mediated by the synthesis of ROS. PMID:23347876

  17. Oxidative mitochondrial DNA damage in peripheral blood mononuclear cells is associated with reduced volumes of hippocampus and subcortical gray matter in chronically HIV-infected patients

    PubMed Central

    Kallianpur, Kalpana J.; Gerschenson, Mariana; Mitchell, Brooks I.; LiButti, Daniel E.; Umaki, Tracie M.; Ndhlovu, Lishomwa C.; Nakamoto, Beau K.; Chow, Dominic C.; Shikuma, Cecilia M.

    2016-01-01

    Cross-sectional relationships were examined between regional brain volumes and mitochondrial DNA (mtDNA) 8-hydroxy-2-deoxyguanosine (8-oxo-dG) in peripheral blood mononuclear cells (PBMCs) of 47 HIV patients [mean age 51 years; 81% with HIV RNA ≤50 copies/mL] on combination antiretroviral therapy. The gene-specific DNA damage and repair assay measured mtDNA 8-oxo-dG break frequency. Magnetic resonance imaging was performed at 3 T. Higher mtDNA 8-oxo-dG was associated with lateral ventricular enlargement and with decreased volumes of hippocampus, pallidum, and total subcortical gray matter, suggesting the involvement of systemic mitochondrial-specific oxidative stress in chronic HIV-related structural brain changes and cognitive difficulties. Clarification of the mechanism may provide potential therapeutic targets. PMID:26923169

  18. Loss of Prohibitin Induces Mitochondrial Damages Altering β-Cell Function and Survival and Is Responsible for Gradual Diabetes Development

    PubMed Central

    Supale, Sachin; Thorel, Fabrizio; Merkwirth, Carsten; Gjinovci, Asllan; Herrera, Pedro L.; Scorrano, Luca; Meda, Paolo; Langer, Thomas; Maechler, Pierre

    2013-01-01

    Prohibitins are highly conserved proteins mainly implicated in the maintenance of mitochondrial function and architecture. Their dysfunctions are associated with aging, cancer, obesity, and inflammation. However, their possible role in pancreatic β-cells remains unknown. The current study documents the expression of prohibitins in human and rodent islets and their key role for β-cell function and survival. Ablation of Phb2 in mouse β-cells sequentially resulted in impairment of mitochondrial function and insulin secretion, loss of β-cells, progressive alteration of glucose homeostasis, and, ultimately, severe diabetes. Remarkably, these events progressed over a 3-week period of time after weaning. Defective insulin supply in β-Phb2−/− mice was contributed by both β-cell dysfunction and apoptosis, temporarily compensated by increased β-cell proliferation. At the molecular level, we observed that deletion of Phb2 caused mitochondrial abnormalities, including reduction of mitochondrial DNA copy number and respiratory chain complex IV levels, altered mitochondrial activity, cleavage of L-optic atrophy 1, and mitochondrial fragmentation. Overall, our data demonstrate that Phb2 is essential for metabolic activation of mitochondria and, as a consequence, for function and survival of β-cells. PMID:23863811

  19. SOD3 Ameliorates H2O2-Induced Oxidative Damage in SH-SY5Y Cells by Inhibiting the Mitochondrial Pathway.

    PubMed

    Yang, Rong; Wei, Li; Fu, Qing-Qing; Wang, Hua; You, Hua; Yu, Hua-Rong

    2016-07-01

    This study was designed to investigate the protective effects of extracellular superoxide dismutase (SOD3) against hydrogen peroxide (H2O2) induced damage in human neuroblastoma SH-SY5Y cells and to elucidate the mechanisms responsible for this beneficial effect. SOD3-overexpressing SH-SY5Y cells were generated by adenoviral vector-mediated infection, and H2O2 was then added into the cell culture system to establish an in vitro model of oxidative stress. Cell viability, the generation of intracellular reactive oxygen species (ROS), the expression and activity of antioxidant enzymes, the levels of lipid peroxidation malondialdehyde (MDA), the expression of mitochondrial apoptosis-related genes, and calcium imaging were examined. Following H2O2 exposure, the over-expression of SOD3 promoted the survival of SH-SY5Y cells; decreased the production of ROS, MDA levels, cytochrome C, caspase-3, caspase-9, and Bax gene expression, and calcium levels; and increased the expression and activity of antioxidant enzyme genes and the expression level of Bcl-2. Together, our data demonstrate that SOD3 ameliorates H2O2-induced oxidative damage in neuroblastoma SH-SY5Y cells by inhibiting the mitochondrial pathway and provide new insights into the functional actions of SOD3 on oxidative stress-induced cell damage. PMID:27084770

  20. Cytoplasmic irradiation results in mitochondrial dysfunction and DRP1-dependent mitochondrial fission

    PubMed Central

    Zhang, Bo; Davidson, Mercy M.; Zhou, Hongning; Wang, Chunxin; Walker, Winsome F.; Hei, Tom K.

    2014-01-01

    Direct DNA damage is often considered the primary cause of cancer in patients exposed to ionizing radiation or environmental carcinogens. While mitochondria are known to play an important role in radiation-induced cellular response, the mechanisms by which cytoplasmic stimuli modulate mitochondrial dynamics and functions are largely unknown. In the present study, we examined changes in mitochondrial dynamics and functions triggered by α particle damage to the mitochondria in human small airway epithelial cells, using a precision microbeam irradiator with a beam width of one micron. Targeted cytoplasmic irradiation using this device resulted in mitochondrial fragmentation and a reduction of cytochrome c oxidase and succinate dehydrogenase activity, when compared with nonirradiated controls, suggesting a reduction in respiratory chain function. Additionally, mitochondrial fragmentation or fission was associated with increased expression of the dynamin-like protein DRP1, which promotes mitochondrial fission. DRP1 inhibition by the drug mdivi-1 prevented radiation-induced mitochondrial fission, but respiratory chain function in mitochondria inhibited by radiation persisted for 12 hr. Irradiated cells also showed an increase in mitochondria-derived superoxide that could be quenched by dimethyl sulfoxide. Taken together, our results provide a mechanistic explanation for the extranuclear, non-targeted effects of ionizing radiation. PMID:24080278

  1. SK channel activation modulates mitochondrial respiration and attenuates neuronal HT-22 cell damage induced by H2O2.

    PubMed

    Richter, Maren; Nickel, Catharina; Apel, Lisa; Kaas, Alexander; Dodel, Richard; Culmsee, Carsten; Dolga, Amalia M

    2015-02-01

    Previous studies established an essential role for small conductance calcium-activated potassium (SK) channels in neuronal cell death pathways induced by glutamate excitotoxicity in cortical neurons in vitro and after cerebral ischemia in vivo. In addition to the intracellular calcium deregulation, glutamate-induced cell death also involves mechanisms of oxidative stress and mitochondrial dysfunction. Therefore, we sought to investigate whether SK channel activation might also affect mechanisms of intrinsic death pathways induced by reactive oxygen species (ROS) such as hydrogen peroxide (H2O2). Exposure of immortalized hippocampal HT-22 cells to H2O2 imposed activation of a cascade of intracellular toxic events resulting in intracellular ROS production, mitochondrial loss of function, and ultimately cell death. Using a pharmacological approach to activate SK channels with CyPPA, we demonstrated a reduction of H2O2-mediated intracellular ROS production and cell death. Interestingly, CyPPA mediated neuroprotection in conditions of extracellular calcium and/or pyruvate depletion, pointing to a neuroprotective role of mitochondrial SK channels. Moreover, CyPPA partially inhibited H2O2-induced mitochondrial superoxide production, but did not prevent mitochondrial membrane depolarization. CyPPA treatment resulted in slight ATP depletion and a reduction of mitochondrial respiration/oxygen consumption. These findings postulate that SK channels mediate a protective effect by preventing neuronal death from subsequent oxidative stress through an adaptive metabolic response at the level of mitochondria. Therefore, SK channel activation may serve as a therapeutic target, where mitochondrial dysfunction and related mechanisms of oxidative stress contribute to progressive degeneration and death of neurons. PMID:25576183

  2. Papuamine causes autophagy following the reduction of cell survival through mitochondrial damage and JNK activation in MCF-7 human breast cancer cells

    PubMed Central

    KANNO, SYU-ICHI; YOMOGIDA, SHIN; TOMIZAWA, AYAKO; YAMAZAKI, HIROYUKI; UKAI, KAZUYO; MANGINDAAN, REMY E.P.; NAMIKOSHI, MICHIO; ISHIKAWA, MASAAKI

    2013-01-01

    We previously reported that extracts of an Indonesian marine sponge Haliclona sp. showed potent cytotoxicity and the induction of apoptosis against human solid cancer cell lines. In this study, we examine the cytotoxic mechanism of the major chemical compound, papuamine, on MCF-7 human breast cancer cells. Papuamine at 5 μM did not show significant cytotoxic effects after incubation for 24 h, but autophagosome vesicular formation was apparent. At 10 μM of papuamine, significant reduction in cell survival was observed at 12 h, and increases in autophagy at this concentration were time-dependent and apparent before the appearance of cytotoxic effects. Both the release of cytochrome c to the cytosol and increase in Bax in the mitochondrial fraction were found to be concentration-dependent. Moreover, mitochondrial membrane potential shows concentration- and time-dependent decreases with exposure to papuamine. The release of cytochrome c has been shown to be accompanied by an increase in JNK activation. 3-Methyladenine (MA), a classical autophagy inhibitor showed increased JNK activation by exposure to papuamine. In conclusion, our results indicate that papuamine causes earlier onset autophagy and delayed reduction of cell survival through mitochondrial damage and JNK activation in MCF-7 cells. PMID:24026338

  3. Space Radiation Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts: Persistence of Damage After Flight and the Effects of Repeat Long Duration Missions

    NASA Technical Reports Server (NTRS)

    George, Kerry; Rhone, Jordan; Chappell, L. J.; Cucinotta, F. A.

    2010-01-01

    Cytogenetic damage was assessed in blood lymphocytes from astronauts before and after they participated in long-duration space missions of three months or more. The frequency of chromosome damage was measured by fluorescence in situ hybridization (FISH) chromosome painting before flight and at various intervals from a few days to many months after return from the mission. For all individuals, the frequency of chromosome exchanges measured within a month of return from space was higher than their prefight yield. However, some individuals showed a temporal decline in chromosome damage with time after flight. Statistical analysis using combined data for all astronauts indicated a significant overall decreasing trend in total chromosome exchanges with time after flight, although this trend was not seen for all astronauts and the yield of chromosome damage in some individuals actually increased with time after flight. The decreasing trend in total exchanges was slightly more significant when statistical analysis was restricted to data collected more than 220 days after return from flight. In addition, limited data on multiple flights show a lack of correlation between time in space and translocation yields. Data from three crewmembers who has participated in two separate long-duration space missions provide limited information on the effect of repeat flights and show a possible adaptive response to space radiation exposure.

  4. Significant accumulation of persistent organic pollutants and dysregulation in multiple DNA damage repair pathways in the electronic-waste-exposed populations

    SciTech Connect

    He, Xiaobo; Jing, Yaqing; Wang, Jianhai; Li, Keqiu; Yang, Qiaoyun; Zhao, Yuxia; Li, Ran; Ge, Jie; Qiu, Xinghua; Li, Guang

    2015-02-15

    Electronic waste (e-waste) has created a worldwide environmental and health problem, by generating a diverse group of hazardous compounds such as persistent organic pollutants (POPs). Our previous studies demonstrated that populations from e-waste exposed region have a significantly higher level of chromosomal aberrancy and incidence of DNA damage. In this study, we further demonstrated that various POPs persisted at a significantly higher concentration in the exposed group than those in the unexposed group. The level of reactive oxygen species and micronucleus rate were also significantly elevated in the exposed group. RNA sequencing analysis revealed 31 genes in DNA damage responses and repair pathways that were differentially expressed between the two groups (Log 2 ratio >1 or <−1). Our data demonstrated that both females and males of the exposed group have activated a series of DNA damage response genes; however many important DNA repair pathways have been dysregulated. Expressions of NEIL1/3 and RPA3, which are critical in initiating base pair and nucleotide excision repairs respectively, have been downregulated in both females and males of the exposed group. In contrast, expression of RNF8, an E3 ligase involved in an error prone non-homologous end joining repair for DNA double strand break, was upregulated in both genders of the exposed group. The other genes appeared to be differentially expressed only when the males or females of the two groups were compared respectively. Importantly, the expression of cell cycle regulatory gene CDC25A that has been implicated in multiple kinds of malignant transformation was significantly upregulated among the exposed males while downregulated among the exposed females. In conclusion, our studies have demonstrated significant correlations between e-waste disposing and POPs accumulation, DNA lesions and dysregulation of multiple DNA damage repair mechanisms in the residents of the e-waste exposed region. - Highlights:

  5. Protease Omi cleaving Hax-1 protein contributes to OGD/R-induced mitochondrial damage in neuroblastoma N2a cells and cerebral injury in MCAO mice

    PubMed Central

    Wu, Jia-yuan; Li, Mei; Cao, Li-juan; Sun, Mei-ling; Chen, Dong; Ren, Hai-gang; Xia, Qin; Tao, Zhou-teng; Qin, Zheng-hong; Hu, Qing-song; Wang, Guang-hui

    2015-01-01

    Aim: In the penumbra after focal cerebral ischemia, an increase of protease Omi is linked to a decrease of Hs1-associated protein X-1 (Hax-1), a protein belonging to the Bcl-2 family. In this study we investigated the mechanisms underlying the regulation of Hax-1 by protease Omi in cerebral ischemia/reperfusion (I/R) injury. Methods: Mouse neuroblastoma N2a cells were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R); cell viability was assessed with MTT assay. Mice underwent 2-h middle cerebral artery occlusion (MCAO) and reperfusion, and the infarct volume was determined with TTC staining. The expression of Omi and Hax-1 was detected using immunoblot and immunofluorescence assays. The mitochondrial membrane potential was measured using TMRM staining. Results: In the brains of MCAO mice, the protein level of Omi was significantly increased, while the protein level of Hax-1 was decreased. Similar changes were observed in OGD/R-treated N2a cells, but the mRNA level of Hax-1 was not changed. Furthermore, in OGD/R-treated N2a cells, knockdown of Omi significantly increased Hax-1 protein level. Immunofluorescence assay showed that Omi and Hax-1 were co-localized in mitochondria of N2a cells. OGD/R caused marked mitochondrial damage and apoptosis in N2a cells, while inhibition of Omi protease activity with UCF-101 (10 μmol/L) or overexpression of Hax-1 could restore the mitochondrial membrane potential and attenuate cell apoptosis. Moreover, pretreatment of MCAO mice with UCF-101 (7.15 mg/kg, ip) could restore Hax-1 expression, inhibit caspase activation, and significantly reduce the infarct volume. Conclusion: Protease Omi impairs mitochondrial function by cleaving Hax-1, which induces apoptosis in OGD/R-treated N2a cells and causes I/R injury in MCAO mice. PMID:26299953

  6. Curcumin Ameliorates Furazolidone-Induced DNA Damage and Apoptosis in Human Hepatocyte L02 Cells by Inhibiting ROS Production and Mitochondrial Pathway.

    PubMed

    Dai, Chongshan; Li, Daowen; Gong, Lijing; Xiao, Xilong; Tang, Shusheng

    2016-01-01

    Furazolidone (FZD), a synthetic nitrofuran derivative, has been widely used as an antibacterial and antiprotozoal agent. Recently, the potential toxicity of FZD has raised concerns, but its mechanism is still unclear. This study aimed to investigate the protective effect of curcumin on FZD-induced cytotoxicity and the underlying mechanism in human hepatocyte L02 cells. The results showed that curcumin pre-treatment significantly ameliorated FZD-induced oxidative stress, characterized by decreased reactive oxygen species (ROS) and malondialdehyde formation, and increased superoxide dismutase, catalase activities and glutathione contents. In addition, curcumin pre-treatment significantly ameliorated the loss of mitochondrial membrane potential, the activations of caspase-9 and -3, and apoptosis caused by FZD. Alkaline comet assay showed that curcumin markedly reduced FZD-induced DNA damage in a dose-dependent manner. Curcumin pre-treatment consistently and markedly down-regulated the mRNA expression levels of p53, Bax, caspase-9 and -3 and up-regulated the mRNA expression level of Bcl-2. Taken together, these results reveal that curcumin protects against FZD-induced DNA damage and apoptosis by inhibiting oxidative stress and mitochondrial pathway. Our study indicated that curcumin may be a promising combiner with FZD to reduce FZD-related toxicity in clinical applications. PMID:27556439

  7. A Bowman-Birk inhibitor induces apoptosis in human breast adenocarcinoma through mitochondrial impairment and oxidative damage following proteasome 20S inhibition.

    PubMed

    Mehdad, A; Brumana, G; Souza, A A; Barbosa, Jarg; Ventura, M M; de Freitas, S M

    2016-01-01

    Proteasome inhibitors are emerging as a new class of chemopreventive agents and have gained huge importance as potential pharmacological tools in breast cancer treatment. Improved understanding of the role played by proteases and their specific inhibitors in humans offers novel and challenging opportunities for preventive and therapeutic intervention. In this study, we demonstrated that the Bowman-Birk protease inhibitor from Vigna unguiculata seeds, named black-eyed pea trypsin/chymotrypsin Inhibitor (BTCI), potently suppresses human breast adenocarcinoma cell viability by inhibiting the activity of proteasome 20S. BTCI induced a negative growth effect against a panel of breast cancer cells, with a concomitant cytostatic effect at the G2/M phase of the cell cycle and an increase in apoptosis, as observed by an augmented number of cells at the sub-G1 phase and annexin V-fluorescin isothiocyanate (FITC)/propidium iodide (PI) staining. In contrast, BTCI exhibited no cytotoxic effect on normal mammary epithelial cells. Moreover, the increased levels of intracellular reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in cells treated with BTCI indicated mitochondrial damage as a crucial cellular event responsible for the apoptotic process. The higher activity of caspase in tumoral cells treated with BTCI in comparison with untreated cells suggests that BTCI induces apoptosis in a caspase-dependent manner. BTCI affected NF-kB target gene expression in both non invasive and invasive breast cancer cell lines, with the effect highly pronounced in the invasive cells. An increased expression of interleukin-8 (IL-8) in both cell lines was also observed. Taken together, these results suggest that BTCI promotes apoptosis through ROS-induced mitochondrial damage following proteasome inhibition. These findings highlight the pharmacological potential and benefit of BTCI in breast cancer treatment. PMID:27551492

  8. A Bowman–Birk inhibitor induces apoptosis in human breast adenocarcinoma through mitochondrial impairment and oxidative damage following proteasome 20S inhibition

    PubMed Central

    Mehdad, A; Brumana, G; Souza, AA; Barbosa, JARG; Ventura, MM; de Freitas, SM

    2016-01-01

    Proteasome inhibitors are emerging as a new class of chemopreventive agents and have gained huge importance as potential pharmacological tools in breast cancer treatment. Improved understanding of the role played by proteases and their specific inhibitors in humans offers novel and challenging opportunities for preventive and therapeutic intervention. In this study, we demonstrated that the Bowman–Birk protease inhibitor from Vigna unguiculata seeds, named black-eyed pea trypsin/chymotrypsin Inhibitor (BTCI), potently suppresses human breast adenocarcinoma cell viability by inhibiting the activity of proteasome 20S. BTCI induced a negative growth effect against a panel of breast cancer cells, with a concomitant cytostatic effect at the G2/M phase of the cell cycle and an increase in apoptosis, as observed by an augmented number of cells at the sub-G1 phase and annexin V-fluorescin isothiocyanate (FITC)/propidium iodide (PI) staining. In contrast, BTCI exhibited no cytotoxic effect on normal mammary epithelial cells. Moreover, the increased levels of intracellular reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in cells treated with BTCI indicated mitochondrial damage as a crucial cellular event responsible for the apoptotic process. The higher activity of caspase in tumoral cells treated with BTCI in comparison with untreated cells suggests that BTCI induces apoptosis in a caspase-dependent manner. BTCI affected NF-kB target gene expression in both non invasive and invasive breast cancer cell lines, with the effect highly pronounced in the invasive cells. An increased expression of interleukin-8 (IL-8) in both cell lines was also observed. Taken together, these results suggest that BTCI promotes apoptosis through ROS-induced mitochondrial damage following proteasome inhibition. These findings highlight the pharmacological potential and benefit of BTCI in breast cancer treatment. PMID:27551492

  9. Up-Regulation of Mitochondrial Antioxidant Superoxide Dismutase Underpins Persistent Cardiac Nutritional-Preconditioning by Long Chain n-3 Polyunsaturated Fatty Acids in the Rat

    PubMed Central

    Abdukeyum, Grace G.; Owen, Alice J.; Larkin, Theresa A.; McLennan, Peter L.

    2016-01-01

    Reactive oxygen species paradoxically underpin both ischaemia/reperfusion (I/R) damage and ischaemic preconditioning (IPC) cardioprotection. Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) are highly susceptible to peroxidation, but are paradoxically cardioprotective. This study tested the hypothesis that LCn-3 PUFA cardioprotection is underpinned by peroxidation, upregulating antioxidant activity to reduce I/R-induced lipid oxidation, and the mechanisms of this nutritional preconditioning contrast to mechanisms of IPC. Rats were fed: fish oil (LCn-3 PUFA); sunflower seed oil (n-6 PUFA); or beef tallow (saturated fat, SF) enriched diets for six weeks. Isolated hearts were subject to: 180 min normoxic perfusion; a 30 min coronary occlusion ischaemia protocol then 120 min normoxic reperfusion; or a 3 × 5 min global IPC protocol, 30 min ischaemia, then reperfusion. Dietary LCn-3 PUFA raised basal: membrane docosahexaenoic acid (22:6n-3 DHA); fatty acid peroxidisability index; concentrations of lipid oxidation products; and superoxide dismutase (MnSOD) activity (but not CuZnSOD or glutathione peroxidase). Infarct size correlated inversely with basal MnSOD activity (r2 = 0.85) in the ischaemia protocol and positively with I/R-induced lipid oxidation (lipid hydroperoxides (LPO), r2 = 0.475; malondialdehyde (MDA), r2 = 0.583) across ischaemia and IPC protocols. While both dietary fish oil and IPC infarct-reduction were associated with reduced I/R-induced lipid oxidation, fish oil produced nutritional preconditioning by prior LCn-3 PUFA incorporation and increased peroxidisability leading to up-regulated mitochondrial SOD antioxidant activity. PMID:26959067

  10. Myristicin from nutmeg induces apoptosis via the mitochondrial pathway and down regulates genes of the DNA damage response pathways in human leukaemia K562 cells.

    PubMed

    Martins, Célia; Doran, Carolina; Silva, Inês C; Miranda, Claudia; Rueff, José; Rodrigues, António S

    2014-07-25

    Myristicin, an allylbenzene, is a major active component of various spices, such as nutmeg and cinnamon, plants from the Umbelliferae family or in some essential oils, such as oils of clove or marjoram. Human exposure to myristicin is low but widespread due to consumption of these spices and essential oils, added to food (e.g. cola drinks) or in traditional medicine. Occasionally high dose exposure occurs, leading to various clinical symptoms, however the molecular mechanisms underlying them are unknown. Our previous studies revealed that myristicin is not genotoxic and yet presented apoptotic activity. Therefore, in this work we assessed the apoptotic mechanisms induced by myristicin in human leukaemia cells. In order to gain further insight on the potential of myristicin to modulate gene expression we also analysed alterations in expression of 84 genes associated with the DNA damage response pathway. The results obtained show that myristicin can induce apoptosis as characterised by alterations in the mitochondrial membrane potential, cytochrome c release, caspase-3 activation, PARP-cleavage and DNA fragmentation. The gene expression profile revealed an overall down regulation of DNA damage response genes after exposure to myristicin, with significant under-expression of genes associated with nucleotide excision repair (ERCC1), double strand break repair (RAD50, RAD51) and DNA damage signalling (ATM) and stress response (GADD45A, GADD45G). On the whole, we demonstrate that myristicin can alter mitochondrial membrane function, induce apoptosis and modulate gene expression in human leukaemia K562 cells. This study provides further detail on the molecular mechanisms underlying the biological activity of myristicin. PMID:24792648

  11. UV-induced histone H2AX phosphorylation and DNA damage related proteins accumulate and persist in nucleotide excision repair-deficient XP-B cells.

    PubMed

    Oh, Kyu-Seon; Bustin, Michael; Mazur, Sharlyn J; Appella, Ettore; Kraemer, Kenneth H

    2011-01-01

    DNA double strand breaks (DSB) may be caused by ionizing radiation. In contrast, UV exposure forms dipyrimidine photoproducts and is not considered an inducer of DSB. We found that uniform or localized UV treatment induced phosphorylation of the DNA damage related (DDR) proteins H2AX, ATM and NBS1 and co-localization of γ-H2AX with the DDR proteins p-ATM, p-NBS1, Rad51 and FANCD2 that persisted for about 6h in normal human fibroblasts. This post-UV phosphorylation was observed in the absence of nucleotide excision repair (NER), since NER deficient XP-B cells (lacking functional XPB DNA repair helicase) and global genome repair-deficient rodent cells also showed phosphorylation and localization of these DDR proteins. Resolution of the DDR proteins was dependent on NER, since they persisted for 24h in the XP-B cells. In the normal and XP-B cells p53 and p21 was detected at 6h and 24h but Mdm2 was not induced in the XP-B cells. Post-UV induction of Wip1 phosphatase was detected in the normal cells but not in the XP-B cells. DNA DSB were detected with a neutral comet assay at 6h and 24h post-UV in the normal and XP-B cells. These results indicate that UV damage can activate the DDR pathway in the absence of NER. However, a later step in DNA damage processing involving induction of Wip1 and resolution of DDR proteins was not observed in the absence of NER. PMID:20947453

  12. Mapping time-course mitochondrial adaptations in the kidney in experimental diabetes.

    PubMed

    Coughlan, Melinda T; Nguyen, Tuong-Vi; Penfold, Sally A; Higgins, Gavin C; Thallas-Bonke, Vicki; Tan, Sih Min; Van Bergen, Nicole J; Sourris, Karly C; Harcourt, Brooke E; Thorburn, David R; Trounce, Ian A; Cooper, Mark E; Forbes, Josephine M

    2016-05-01

    Oxidative phosphorylation (OXPHOS) drives ATP production by mitochondria, which are dynamic organelles, constantly fusing and dividing to maintain kidney homoeostasis. In diabetic kidney disease (DKD), mitochondria appear dysfunctional, but the temporal development of diabetes-induced adaptations in mitochondrial structure and bioenergetics have not been previously documented. In the present study, we map the changes in mitochondrial dynamics and function in rat kidney mitochondria at 4, 8, 16 and 32 weeks of diabetes. Our data reveal that changes in mitochondrial bioenergetics and dynamics precede the development of albuminuria and renal histological changes. Specifically, in early diabetes (4 weeks), a decrease in ATP content and mitochondrial fragmentation within proximal tubule epithelial cells (PTECs) of diabetic kidneys were clearly apparent, but no changes in urinary albumin excretion or glomerular morphology were evident at this time. By 8 weeks of diabetes, there was increased capacity for mitochondrial permeability transition (mPT) by pore opening, which persisted over time and correlated with mitochondrial hydrogen peroxide (H2O2) generation and glomerular damage. Late in diabetes, by week 16, tubular damage was evident with increased urinary kidney injury molecule-1 (KIM-1) excretion, where an increase in the Complex I-linked oxygen consumption rate (OCR), in the context of a decrease in kidney ATP, indicated mitochondrial uncoupling. Taken together, these data show that changes in mitochondrial bioenergetics and dynamics may precede the development of the renal lesion in diabetes, and this supports the hypothesis that mitochondrial dysfunction is a primary cause of DKD. PMID:26831938

  13. Persistent Activation of NF-κB in BRCA1-Deficient Mammary Progenitors Drives Aberrant Proliferation and Accumulation of DNA Damage.

    PubMed

    Sau, Andrea; Lau, Rosanna; Cabrita, Miguel A; Nolan, Emma; Crooks, Peter A; Visvader, Jane E; Pratt, M A Christine

    2016-07-01

    Human BRCA1 mutation carriers and BRCA1-deficient mouse mammary glands contain an abnormal population of mammary luminal progenitors that can form 3D colonies in a hormone-independent manner. The intrinsic cellular regulatory defect in these presumptive breast cancer precursors is not known. We have discovered that nuclear factor kappaB (NF-κB) (p52/RelB) is persistently activated in a subset of BRCA1-deficient mammary luminal progenitors. Hormone-independent luminal progenitor colony formation required NF-κB, ataxia telangiectasia-mutated (ATM), and the inhibitor of kappaB kinase, IKKα. Progesterone (P4)-stimulated proliferation resulted in a marked enhancement of DNA damage foci in Brca1(-/-) mouse mammary. In vivo, NF-κB inhibition prevented recovery of Brca1(-/-) hormone-independent colony-forming cells. The majority of human BRCA1(mut/+) mammary glands showed marked lobular expression of nuclear NF-κB. We conclude that the aberrant proliferative capacity of Brca1(-/-) luminal progenitor cells is linked to the replication-associated DNA damage response, where proliferation of mammary progenitors is perpetuated by damage-induced, autologous NF-κB signaling. PMID:27292187

  14. Ultraviolet B, melanin and mitochondrial DNA: Photo-damage in human epidermal keratinocytes and melanocytes modulated by alpha-melanocyte-stimulating hormone

    PubMed Central

    Böhm, Markus; Hill, Helene Z.

    2016-01-01

    Alpha-melanocyte-stimulating hormone (alpha-MSH) increases melanogenesis and protects from UV-induced DNA damage. However, its effect on mitochondrial DNA (mtDNA) damage is unknown. We have addressed this issue in a pilot study using human epidermal keratinocytes and melanocytes incubated with alpha-MSH and irradiated with UVB. Real-time touchdown PCR was used to quantify total and deleted mtDNA. The deletion detected encompassed the common deletion but was more sensitive to detection. There were 4.4 times more mtDNA copies in keratinocytes than in melanocytes. Irradiation alone did not affect copy numbers. Alpha-MSH slightly increased copy numbers in both cell types in the absence of UVB and caused a similar small decrease in copy number with dose in both cell types. Deleted copies were nearly twice as frequent in keratinocytes as in melanocytes. Alpha-MSH reduced the frequency of deleted copies by half in keratinocytes but not in melanocytes. UVB dose dependently led to an increase in the deleted copy number in alpha-MSH-treated melanocytes. UVB irradiation had little effect on deleted copy number in alpha-MSH-treated keratinocytes. In summary, alpha-MSH enhances mtDNA damage in melanocytes presumably by increased melanogenesis, while α-MSH is protective in keratinocytes, the more so in the absence of irradiation. PMID:27303631

  15. Low doses of ultraviolet radiation and oxidative damage induce dramatic accumulation of mitochondrial DNA replication intermediates, fork regression, and replication initiation shift

    PubMed Central

    Torregrosa-Muñumer, Rubén; Goffart, Steffi; Haikonen, Juha A.; Pohjoismäki, Jaakko L. O.

    2015-01-01

    Mitochondrial DNA is prone to damage by various intrinsic as well as environmental stressors. DNA damage can in turn cause problems for replication, resulting in replication stalling and double-strand breaks, which are suspected to be the leading cause of pathological mtDNA rearrangements. In this study, we exposed cells to subtle levels of oxidative stress or UV radiation and followed their effects on mtDNA maintenance. Although the damage did not influence mtDNA copy number, we detected a massive accumulation of RNA:DNA hybrid–containing replication intermediates, followed by an increase in cruciform DNA molecules, as well as in bidirectional replication initiation outside of the main replication origin, OH. Our results suggest that mitochondria maintain two different types of replication as an adaptation to different cellular environments; the RNA:DNA hybrid–involving replication mode maintains mtDNA integrity in tissues with low oxidative stress, and the potentially more error tolerant conventional strand-coupled replication operates when stress is high. PMID:26399294

  16. Dioscin Induces Apoptosis in Human Cervical Carcinoma HeLa and SiHa Cells through ROS-Mediated DNA Damage and the Mitochondrial Signaling Pathway.

    PubMed

    Zhao, Xinwei; Tao, Xufeng; Xu, Lina; Yin, Lianhong; Qi, Yan; Xu, Youwei; Han, Xu; Peng, Jinyong

    2016-01-01

    Dioscin, a natural product, has activity against glioblastoma multiforme, lung cancer and colon cancer. In this study, the effects of dioscin against human cervical carcinoma HeLa and SiHa cells were further confirmed, and the possible mechanism(s) were investigated. A transmission electron microscopy (TEM) assay and DAPI staining were used to detect the cellular morphology. Flow cytometry was used to assay cell apoptosis, ROS and Ca(2+) levels. Single cell gel electrophoresis and immunofluorescence assays were used to test DNA damage and cytochrome C release. The results showed that dioscin significantly inhibited cell proliferation and caused DNA damage in HeLa and SiHa cells. The mechanistic investigation showed that dioscin caused the release of cytochrome C from mitochondria into the cytosol. In addition, dioscin significantly up-regulated the protein levels of Bak, Bax, Bid, p53, caspase-3, caspase-9, and down-regulated the protein levels of Bcl-2 and Bcl-xl. Our work thus demonstrated that dioscin notably induces apoptosis in HeLa and SiHa cells through adjusting ROS-mediated DNA damage and the mitochondrial signaling pathway. PMID:27271587

  17. Ultraviolet B, melanin and mitochondrial DNA: Photo-damage in human epidermal keratinocytes and melanocytes modulated by alpha-melanocyte-stimulating hormone.

    PubMed

    Böhm, Markus; Hill, Helene Z

    2016-01-01

    Alpha-melanocyte-stimulating hormone (alpha-MSH) increases melanogenesis and protects from UV-induced DNA damage. However, its effect on mitochondrial DNA (mtDNA) damage is unknown. We have addressed this issue in a pilot study using human epidermal keratinocytes and melanocytes incubated with alpha-MSH and irradiated with UVB. Real-time touchdown PCR was used to quantify total and deleted mtDNA. The deletion detected encompassed the common deletion but was more sensitive to detection. There were 4.4 times more mtDNA copies in keratinocytes than in melanocytes. Irradiation alone did not affect copy numbers. Alpha-MSH slightly increased copy numbers in both cell types in the absence of UVB and caused a similar small decrease in copy number with dose in both cell types. Deleted copies were nearly twice as frequent in keratinocytes as in melanocytes. Alpha-MSH reduced the frequency of deleted copies by half in keratinocytes but not in melanocytes. UVB dose dependently led to an increase in the deleted copy number in alpha-MSH-treated melanocytes. UVB irradiation had little effect on deleted copy number in alpha-MSH-treated keratinocytes. In summary, alpha-MSH enhances mtDNA damage in melanocytes presumably by increased melanogenesis, while α-MSH is protective in keratinocytes, the more so in the absence of irradiation. PMID:27303631

  18. Effect of hyperbaric oxygenation on mitochondrial function of neuronal cells in the cortex of neonatal rats after hypoxic-ischemic brain damage

    PubMed Central

    Yang, L.; Hei, M.Y.; Dai, J.J.; Hu, N.; Xiang, X.Y.

    2016-01-01

    The timing and mechanisms of protection by hyperbaric oxygenation (HBO) in hypoxic-ischemic brain damage (HIBD) have only been partially elucidated. We monitored the effect of HBO on the mitochondrial function of neuronal cells in the cerebral cortex of neonatal rats after HIBD. Neonatal Sprague-Dawley rats (total of 360 of both genders) were randomly divided into normal control, HIBD, and HIBD+HBO groups. The HBO treatment began immediately after hypoxia-ischemia (HI) and continued once a day for 7 consecutive days. Animals were euthanized 0, 2, 4, 6, and 12 h post-HI to monitor the changes in mitochondrial membrane potential (ΔΨm) occurring soon after a single dose of HBO treatment, as well as 2, 3, 4, 5, 6, and 7 days post-HI to study ΔΨm changes after a series of HBO treatments. Fluctuations in ΔΨm were observed in the ipsilateral cortex in both HIBD and HIBD+HBO groups. Within 2 to 12 h after HI insult, the ΔΨm of the HIBD and HIBD+HBO groups recovered to some extent. A secondary drop in ΔΨm was observed in both groups during the 1-4 days post-HI period, but was more severe in the HIBD+HBO group. There was a secondary recovery of ΔΨm observed in the HIBD+HBO group, but not in the HIBD group, during the 5-7 days period after HI insult. HBO therapy may not lead to improvement of neural cell mitochondrial function in the cerebral cortex in the early stage post-HI, but may improve it in the sub-acute stage post-HI. PMID:27119428

  19. Effect of hyperbaric oxygenation on mitochondrial function of neuronal cells in the cortex of neonatal rats after hypoxic-ischemic brain damage.

    PubMed

    Yang, L; Hei, M Y; Dai, J J; Hu, N; Xiang, X Y

    2016-01-01

    The timing and mechanisms of protection by hyperbaric oxygenation (HBO) in hypoxic-ischemic brain damage (HIBD) have only been partially elucidated. We monitored the effect of HBO on the mitochondrial function of neuronal cells in the cerebral cortex of neonatal rats after HIBD. Neonatal Sprague-Dawley rats (total of 360 of both genders) were randomly divided into normal control, HIBD, and HIBD+HBO groups. The HBO treatment began immediately after hypoxia-ischemia (HI) and continued once a day for 7 consecutive days. Animals were euthanized 0, 2, 4, 6, and 12 h post-HI to monitor the changes in mitochondrial membrane potential (ΔΨm) occurring soon after a single dose of HBO treatment, as well as 2, 3, 4, 5, 6, and 7 days post-HI to study ΔΨm changes after a series of HBO treatments. Fluctuations in ΔΨm were observed in the ipsilateral cortex in both HIBD and HIBD+HBO groups. Within 2 to 12 h after HI insult, the ΔΨm of the HIBD and HIBD+HBO groups recovered to some extent. A secondary drop in ΔΨm was observed in both groups during the 1-4 days post-HI period, but was more severe in the HIBD+HBO group. There was a secondary recovery of ΔΨm observed in the HIBD+HBO group, but not in the HIBD group, during the 5-7 days period after HI insult. HBO therapy may not lead to improvement of neural cell mitochondrial function in the cerebral cortex in the early stage post-HI, but may improve it in the sub-acute stage post-HI. PMID:27119428

  20. A defect in the mitochondrial complex III, but not complex IV, triggers early ROS-dependent damage in defined brain regions

    PubMed Central

    Diaz, Francisca; Garcia, Sofia; Padgett, Kyle R.; Moraes, Carlos T.

    2012-01-01

    We have created two neuron-specific mouse models of mitochondrial electron transport chain deficiencies involving defects in complex III (CIII) or complex IV (CIV). These conditional knockouts (cKOs) were created by ablation of the genes coding for the Rieske iron–sulfur protein (RISP) and COX10, respectively. RISP is one of the catalytic subunits of CIII and COX10 is an assembly factor indispensable for the maturation of Cox1, one of the catalytic subunits of CIV. Although the rates of gene deletion, protein loss and complex dysfunction were similar, the RISP cKO survived 3.5 months of age, whereas the COX10 cKO survived for 10–12 months. The RISP cKO had a sudden death, with minimal behavioral changes. In contrast, the COX10 cKO showed a distinctive behavioral phenotype with onset at 4 months of age followed by a slower but progressive neurodegeneration. Curiously, the piriform and somatosensory cortices were more vulnerable to the CIII defect whereas cingulate cortex and to a less extent piriform cortex were affected preferentially by the CIV defect. In addition, the CIII model showed severe and early reactive oxygen species damage, a feature not observed until very late in the pathology of the CIV model. These findings illustrate how specific respiratory chain defects have distinct molecular mechanisms, leading to distinct pathologies, akin to the clinical heterogeneity observed in patients with mitochondrial diseases. PMID:22914734

  1. Crocin protects retinal ganglion cells against H2O2-induced damage through the mitochondrial pathway and activation of NF-κB.

    PubMed

    Lv, Bochang; Chen, Tao; Xu, Zhiguo; Huo, Fuquan; Wei, Yanyan; Yang, Xinguang

    2016-01-01

    Glaucoma is a degenerative nerve disorder that results in irreversible blindness. It has been reported that the apoptosis of retinal ganglion cells (RGCs) is a hallmark of glaucoma. Oxidative stress is one of the major factors that cause apoptosis of RGCs. Crocin has many beneficial effects, including antioxidant and anti-apoptotic actions. However, the mechanism by which crocin protects against oxidative stress‑induced damage to RGCs remains unclear. The present study aimed to investigate the mechanism by which crocin protects RGC-5 cells against H2O2-induced damage. H2O2 was used to establish a model of oxidative stress injury in RGC-5 cells to mimic the development of glaucoma in vitro. Different concentrations (0.1 and 1 µM) of crocin were added to test whether crocin was capable of protecting RGCs from H2O2-induced damage. WST-1, lactic dehydrogenase (LDH) release and Annexin V/FITC assays were then performed. Levels of reactive oxygen species (ROS) were detected using a ROS assay kit, mitochondrial membrane potential (ΔΨm) was analyzed by JC-1 staining, caspase-3 activity was examined using a Caspase-3 assay kit, and the protein levels of Bax, Bcl-1 and cytochrome c were measured using western blot analysis. In addition, the protein level of phosphorylated nuclear factor-κB (p-NF-κB) p65 was also evaluated using western blot analysis. The results showed that crocin protected RGC-5 cells from apoptosis, decreased LDH release and enhanced cell viability. Additional experiments demonstrated that crocin decreased ROS levels, increased ΔΨm, downregulated the protein expression of Bax and cytochrome c, promoted Bcl-2 protein expression and activated NF-κB. Taken together, the findings of this study indicate that crocin prevented H2O2‑induced damage to RGCs through the mitochondrial pathway and activation of NF-κB. PMID:26718031

  2. Damage to mitochondrial complex I during cardiac ischemia reperfusion injury is reduced indirectly by anti-anginal drug ranolazine

    PubMed Central

    Gadicherla, Ashish K.; Stowe, David F.; Antholine, William E.; Yang, Meiying; Camara, Amadou K.S.

    2011-01-01

    Ranolazine (Ran), an anti-anginal drug, is a late Na+ channel current blocker that is also believed to attenuate fatty acid oxidation and mitochondrial respiratory complex I activity, especially during ischemia. In this study, we investigated if Ran's protective effect against cardiac ischemia/reperfusion (IR) injury is mediated at the mitochondrial level and specifically if respiratory complex I (NADH oxidoreductase) function is protected. We treated isolated and perfused guinea pig hearts with Ran just before 30 min ischemia and then isolated cardiac mitochondria at the end of 30 min ischemia and/or 30 min ischemia followed by 10 min reperfusion. We utilized spectrophotometric and histochemical techniques to assay complex I activity, western blot analysis for complex I subunit NDUFA9, electron paramagnetic resonance for activity of complex I Fe-S clusters, ELISA for determination of protein acetylation, native gel histochemical staining for respiratory supercomplex assemblies, and high pressure liquid chromatography for cardiolipin integrity; cardiac function was measured during IR. Ran treated hearts showed higher complex I activity and greater detectable complex I protein levels compared to untreated IR hearts. Ran treatment also led to more normalized electron transfer via Fe-S centers, supercomplex assembly and cardiolipin integrity. These improvements in complex I structure and function with Ran were associated with improved cardiac function after IR. However, these protective effects of Ran are not mediated by a direct action on mitochondria, but rather indirectly via cytosolic mechanisms that lead to less oxidation and better structural integrity of complex I. PMID:22178605

  3. Melatonin Prevents Mitochondrial Damage Induced by Doxorubicin in Mouse Fibroblasts Through Ampk-Ppar Gamma-Dependent Mechanisms

    PubMed Central

    Guven, Celal; Taskin, Eylem; Akcakaya, Handan

    2016-01-01

    Background Doxorubicin (brand name: Adriamycin®) is used to treat solid tissue cancer but it also affects noncancerous tissues. Its mechanism of cytotoxicity is probably related to increased oxidation, mitochondrial dysfunction, and apoptosis. Melatonin is reported to have antiapoptotic and antioxidative effects. The aim of this study was to determine whether melatonin would counteract in vitro cytotoxicity of doxorubicin in mouse fibroblasts and determine the pathway of its action against doxorubicin-induced apoptosis. Material/Methods We measured markers of apoptosis (cytochrome-c, mitochondrial membrane potential, and apoptotic cell number) and oxidative stress (total oxidant and antioxidant status) and calculated oxidant stress index in 4 groups of fibroblasts: controls, melatonin-treated, doxorubicin-treated, and fibroblasts concomittantly treated with a combination of melatonin and doxorubicin. Results Melatonin given with doxorubicin succesfully countered apoptosis generated by doxorubicin alone, which points to its potential as a protective agent against cell death in doxorubicin chemotherapy. This also implies that patients should be receiving doxorubicin treatment when their physiological level of melatonin is at its highest, which is early in the morning. Conclusions This physiological level may not be high enough to overcome doxorubicin-induced oxidative stress, but adjuvant melatonin treatment may improve quality of life. Further research is needed to verify our findings. PMID:26861593

  4. Higher Initial DNA Damage and Persistent Cell Cycle Arrest after Carbon Ion Irradiation Compared to X-irradiation in Prostate and Colon Cancer Cells.

    PubMed

    Suetens, Annelies; Konings, Katrien; Moreels, Marjan; Quintens, Roel; Verslegers, Mieke; Soors, Els; Tabury, Kevin; Grégoire, Vincent; Baatout, Sarah

    2016-01-01

    The use of charged-particle beams, such as carbon ions, is becoming a more and more attractive treatment option for cancer therapy. Given the precise absorbed dose-localization and an increased biological effectiveness, this form of therapy is much more advantageous compared to conventional radiotherapy, and is currently being used for treatment of specific cancer types. The high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. In order to better understand the underlying mechanisms responsible for the increased biological effectiveness, we investigated the DNA damage and repair kinetics and cell cycle progression in two p53 mutant cell lines, more specifically a prostate (PC3) and colon (Caco-2) cancer cell line, after exposure to different radiation qualities. Cells were irradiated with various absorbed doses (0, 0.5, and 2 Gy) of accelerated (13)C-ions at the Grand Accélérateur National d'Ions Lourds facility (Caen, France) or with X-rays (0, 0.1, 0.5, 1, 2, and 5 Gy). Microscopic analysis of DNA double-strand breaks showed dose-dependent increases in γ-H2AX foci numbers and foci occupancy after exposure to both types of irradiation, in both cell lines. However, 24 h after exposure, residual damage was more pronounced after lower doses of carbon ion irradiation compared to X-irradiation. Flow cytometric analysis showed that carbon ion irradiation induced a permanent G2/M arrest in PC3 cells at lower doses (2 Gy) compared to X-rays (5 Gy), while in Caco-2 cells the G2/M arrest was transient after irradiation with X-rays (2 and 5 Gy) but persistent after exposure to carbon ions (2 Gy). PMID:27148479

  5. Higher Initial DNA Damage and Persistent Cell Cycle Arrest after Carbon Ion Irradiation Compared to X-irradiation in Prostate and Colon Cancer Cells

    PubMed Central

    Suetens, Annelies; Konings, Katrien; Moreels, Marjan; Quintens, Roel; Verslegers, Mieke; Soors, Els; Tabury, Kevin; Grégoire, Vincent; Baatout, Sarah

    2016-01-01

    The use of charged-particle beams, such as carbon ions, is becoming a more and more attractive treatment option for cancer therapy. Given the precise absorbed dose-localization and an increased biological effectiveness, this form of therapy is much more advantageous compared to conventional radiotherapy, and is currently being used for treatment of specific cancer types. The high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. In order to better understand the underlying mechanisms responsible for the increased biological effectiveness, we investigated the DNA damage and repair kinetics and cell cycle progression in two p53 mutant cell lines, more specifically a prostate (PC3) and colon (Caco-2) cancer cell line, after exposure to different radiation qualities. Cells were irradiated with various absorbed doses (0, 0.5, and 2 Gy) of accelerated 13C-ions at the Grand Accélérateur National d’Ions Lourds facility (Caen, France) or with X-rays (0, 0.1, 0.5, 1, 2, and 5 Gy). Microscopic analysis of DNA double-strand breaks showed dose-dependent increases in γ-H2AX foci numbers and foci occupancy after exposure to both types of irradiation, in both cell lines. However, 24 h after exposure, residual damage was more pronounced after lower doses of carbon ion irradiation compared to X-irradiation. Flow cytometric analysis showed that carbon ion irradiation induced a permanent G2/M arrest in PC3 cells at lower doses (2 Gy) compared to X-rays (5 Gy), while in Caco-2 cells the G2/M arrest was transient after irradiation with X-rays (2 and 5 Gy) but persistent after exposure to carbon ions (2 Gy). PMID:27148479

  6. Mitochondrial DNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression in cultured cells of patients with MERRF syndrome.

    PubMed

    Wu, Shi-Bei; Ma, Yi-Shing; Wu, Yu-Ting; Chen, Yin-Chiu; Wei, Yau-Huei

    2010-06-01

    Myoclonic epilepsy and ragged-red fibers (MERRF) syndrome is a rare disorder characterized by myoclonus, muscle weakness, cerebellar ataxia, heart conduction block, and dementia. It has been documented that 80-90% of the patients with MERRF syndrome are caused by the A8344G mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We and other investigators have reported that the mtDNA mutation results in not only inefficient generation of adenosine triphosphate but also increased production of reactive oxygen species (ROS) in cultured cells harboring A8344G mutation of mtDNA. In addition, we found an imbalance in the gene expression of antioxidant enzymes in the skin fibroblasts of MERRF patients. The mRNA, protein, and enzyme activity levels of manganese-superoxide dismutase were increased, but those of Cu,Zn-SOD, catalase, and glutathione peroxidase did not show significant changes. Recently, we showed that the excess ROS could damage voltage-dependent anion channel, prohibitin, Lon protease, and aconitase in the MERRF cells. Moreover, there was a dramatic increase in the gene expression and activity of matrix metalloproteinase 1, which may contribute to the cytoskeleton remodeling involved in the weakness and atrophy of muscle commonly seen in MERRF patients. Taken together, we suggest that mtDNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression are involved in the pathogenesis and progression of MERRF syndrome. PMID:20411357

  7. Activation of mitochondrial apoptotic pathway in mantle cell lymphoma: high sensitivity to mitoxantrone in cases with functional DNA-damage response genes.

    PubMed

    Ferrer, Ana; Marcé, Silvia; Bellosillo, Beatriz; Villamor, Neus; Bosch, Francesc; López-Guillermo, Armando; Espinet, Blanca; Solé, Francesc; Montserrat, Emili; Campo, Elias; Colomer, Dolors

    2004-11-25

    Mantle cell lymphoma (MCL) is a mature B-cell proliferation characterized by the presence of translocation t(11;14)(q13;q32), an aggressive clinical course, and poor response to chemotherapy. The majority of drugs currently used in the treatment of lymphoproliferative disorders induce cell death by triggering apoptosis, but few data concerning drug-induced apoptosis in MCL have been reported. We have analysed the mechanisms of drug-induced cell death in four cell lines with the t(11;14) and in primary cells from 10 patients with MCL. Mitoxantrone, a topoisomerase II inhibitor, induced a strong cytotoxic effect in three cell lines (JVM-2, REC-1, and Granta 519), and in primary MCL cells. This cytotoxic effect due to apoptosis induction was observed despite the presence of either p53 or ATM abnormalities. However, no cytotoxic effect was detected after incubation with DNA-damaging agents in the NCEB-1 cell line, carrying p53 and ATM alterations, despite the presence of functional mitochondrial machinery. These results support that mitoxantrone can be effective in the treatment of MCL but that this activity requires the integrity of functional DNA-damage response genes. PMID:15480431

  8. Selenium (sodium selenite) causes cytotoxicity and apoptotic mediated cell death in PLHC-1 fish cell line through DNA and mitochondrial membrane potential damage.

    PubMed

    Selvaraj, Vellaisamy; Tomblin, Justin; Yeager Armistead, Mindy; Murray, Elizabeth

    2013-01-01

    Elevated concentration of selenium poses a toxic threat to organisms inhabiting aquatic ecosystems influenced by excessive inputs from anthropogenic sources. Selenium is also an essential micronutrient in living things, particularly in fish, and provides antioxidant properties to tissues. Whole fish and hepatocytes in primary culture show selenite toxicity above threshold levels. The present study was designed to investigate the process by which selenite exposure causes cellular toxicity and apoptotic and necrotic cell death in fish hepatoma cell line PLHC-1. PLHC-1 cells were exposed to various selenite concentrations (1, 10, 50 and 100 μM) for 10, 20 and 40 h intervals. The 24h inhibitory concentration 50 (IC₅₀) of selenite in PLHC-1 cell line was found to be 237 μM. Flow cytometery data showed that selenite exposed cells promote apoptotic and necrotic mediated cell death when selenite concentrations were ≥10 μM compared to control. Selenite exposure was associated with a significant increase of caspase-3 activities suggesting the induction of apoptosis. Selenite exposure at high levels (≥10 μM) and longer exposure times (≥20 h) induces mitochondrial membrane potential damage (ΔΨ(m)), DNA damage and elevated production of ROS which could be associated with cell death. PMID:23158585

  9. Melatonin prevents cytosolic calcium overload, mitochondrial damage and cell death due to toxically high doses of dexamethasone-induced oxidative stress in human neuroblastoma SH-SY5Y cells.

    PubMed

    Suwanjang, Wilasinee; Abramov, Andrey Y; Charngkaew, Komgrid; Govitrapong, Piyarat; Chetsawang, Banthit

    2016-07-01

    Stressor exposure activates the hypothalamic-pituitary-adrenal (HPA) axis and causes elevations in the levels of glucocorticoids (GC) from the adrenal glands. Increasing evidence has demonstrated that prolonged exposure to high GC levels can lead to oxidative stress, calcium deregulation, mitochondrial dysfunction and apoptosis in a number of cell types. However, melatonin, via its antioxidant activity, exhibits a neuroprotective effect against oxidative stress-induced cell death. Therefore, in the present study, we explored the protective effect of melatonin in GC-induced toxicity in human neuroblastoma SH-SY5Y cells. Cellular treatment with the toxically high doses of the synthetic GC receptor agonist, dexamethasone (DEX) elicited marked decreases in the levels of glutathione and increases in ROS production, lipid peroxidation and cell death. DEX toxicity also induced increases in the levels of cytosolic calcium and mitochondrial fusion proteins (Mfn1 and Opa1) but decreases in the levels of mitochondrial fission proteins (Fis1 and Drp1). Mitochondrial damage was observed in large proportions of the DEX-treated cells. Pretreatment of the cells with melatonin substantially prevented the DEX-induced toxicity. These results suggest that melatonin might exert protective effects against oxidative stress, cytosolic calcium overload and mitochondrial damage in DEX-induced neurotoxicity. PMID:27155536

  10. Mitochondrial protein oxidation in yeast mutants lacking manganese-(MnSOD) or copper- and zinc-containing superoxide dismutase (CuZnSOD): evidence that MnSOD and CuZnSOD have both unique and overlapping functions in protecting mitochondrial proteins from oxidative damage.

    PubMed

    O'Brien, Kristin M; Dirmeier, Reinhard; Engle, Marcella; Poyton, Robert O

    2004-12-10

    Saccharomyces cerevisiae expresses two forms of superoxide dismutase (SOD): MnSOD, encoded by SOD2, which is located within the mitochondrial matrix, and CuZnSOD, encoded by SOD1, which is located in both the cytosol and the mitochondrial intermembrane space. Because two different SOD enzymes are located in the mitochondrion, we examined the relative roles of each in protecting mitochondria against oxidative stress. Using protein carbonylation as a measure of oxidative stress, we have found no correlation between overall levels of respiration and the level of oxidative mitochondrial protein damage in either wild type or sod mutant strains. Moreover, mitochondrial protein carbonylation levels in sod1, sod2, and sod1sod2 mutants are not elevated in cells harvested from mid-logarithmic and early stationary phases, suggesting that neither MnSOD nor CuZnSOD is required for protecting the majority of mitochondrial proteins from oxidative damage during these early phases of growth. During late stationary phase, mitochondrial protein carbonylation increases in all strains, particularly in sod1 and sod1sod2 mutants. By using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, we have found that specific proteins become carbonylated in sod1 and sod2 mutants. We identified six mitochondrial protein spots representing five unique proteins that become carbonylated in a sod1 mutant and 19 mitochondrial protein spots representing 11 unique proteins that become carbonylated in a sod2 mutant. Although some of the same proteins are carbonylated in both mutants, other proteins are not. These findings indicate that MnSOD and CuZnSOD have both unique and overlapping functions in the mitochondrion. PMID:15385544

  11. The resistance of electron-transport chain Fe-S clusters to oxidative damage during the reaction of peroxynitrite with mitochondrial complex II and rat-heart pericardium.

    PubMed

    Pearce, Linda L; Martinez-Bosch, Sandra; Manzano, Elisenda Lopez; Winnica, Daniel E; Epperly, Michael W; Peterson, Jim

    2009-05-01

    The effects of peroxynitrite and nitric oxide on the iron-sulfur clusters in complex II (succinate dehydrogenase) isolated from bovine heart have been studied primarily by EPR spectroscopy and no measurable damage to the constitutive 2Fe-2S, 3Fe-4S, or 4Fe-4S clusters was observed. The enzyme can be repeatedly oxidized with a slight excess of peroxynitrite and then quantitatively re-reduced with succinate. When added in large excess, peroxynitrite reacted with at least one tyrosine in each subunit of complex II to form 3-nitrotyrosines, but activity was barely compromised. Examination of rat-heart pericardium subjected to conditions leading to peroxynitrite production showed a small inhibition of complex II (16%) and a greater inhibition of aconitase (77%). In addition, experiments performed with excesses of sodium citrate and sodium succinate on rat-heart pericardium indicated that the "g approximately 2.01" EPR signal observed immediately following the beginning of conditions modeling oxidative/nitrosative stress, could be a consequence of both reversible oxidation of the constitutive 3Fe-4S cluster in complex II and degradation of the 4Fe-4S cluster in aconitase. However, the net signal envelope, which becomes apparent in less than 1min following the start of oxidative/nitrosative conditions, is dominated by the component arising from complex II. Taking into account the findings of a previous study concerning complexes I and III (L.L. Pearce, A.J. Kanai, M.W. Epperly, J. Peterson, Nitrosative stress results in irreversible inhibition of purified mitochondrial complexes I and III without modification of cofactors, Nitric Oxide 13 (2005) 254-263) it is now apparent that, with the exception of the cofactor in aconitase, mammalian (mitochondrial) iron-sulfur clusters are surprisingly resistant to degradation stemming from oxidative/nitrosative stress. PMID:19118636

  12. Aging augments mitochondrial susceptibility to heat stress

    PubMed Central

    Haak, Jodie L.; Buettner, Garry R.; Spitz, Douglas R.; Kregel, Kevin C.

    2009-01-01

    The pathophysiology of aging is accompanied by a decline in tolerance to environmental stress. While mitochondria are primary suspects in the etiology of aging, little is known about their ability to tolerate perturbations to homeostasis in older organisms. To investigate the role of mitochondria in the increased susceptibility to heat stress that accompanies aging, young and old Fischer 344 rats underwent a heat stress protocol known to elicit exaggerated cellular damage with aging. At either 2 or 24 h after heat stress, livers were removed from animals, and hepatic mitochondria were isolated. Electron microscopy revealed extensive morphological damage to mitochondria from young and, to a greater extent, old rats after heat stress. There was also a significant loss of cytochrome c from old, but not young, mitochondria and a persistent increase in 4-hydroxynonenal-modified proteins in old vs. young mitochondria exposed to heat stress. Electron paramagnetic resonance measurements of superoxide indicate greater superoxide production from mitochondria of old compared with young animals and suggest that mitochondrial integrity was altered during heat stress. The mitochondrial stress response, which functions to correct stress-induced damage to mitochondrial proteins, was also blunted in old rats. Delayed and reduced levels of heat shock protein 60 (Hsp60), the main inducible mitochondrial stress protein, were observed in old compared with young mitochondria after heat stress. Additionally, the amount of Hsp10 protein increased in young, but not old, rat liver mitochondria after hyperthermic challenge. Taken together, these data suggest that mitochondria in old animals are more vulnerable to incurring and less able to repair oxidative damage that occurs in response to a physiologically relevant heat stress. PMID:19144753

  13. Low Expression of Mfn2 Is Associated with Mitochondrial Damage and Apoptosis of Ovarian Tissues in the Premature Ovarian Failure Model

    PubMed Central

    Wang, Lingjuan; Bai, Ge; Xiang, Wenpei

    2015-01-01

    Background This study aimed to construct a working model for detecting the mitochondrial damage and expression of Mfn2. It furthermore explored the pathogenesis of premature ovarian failure (POF) induced by cisplatin. Method Forty young female mice were divided randomly into two groups. The first was the treatment group intraperitoneally administered cisplatin (1.5mg/kg). The untreated control group was likewise injected with physiological saline for 10 days. One month later, we observed the ovarian weight and morphological changes, particularly the development of follicles and concentration of sex hormones. Immunohistochemistry and western blotting were used to measure the two groups. We later evaluated ovarian cell apoptosis with TUNEL and analyzed Bcl-2 and Bax levels. We used transmission electron microscopy in order to observe the ultrastructure of ovarian cells. The phosphomolybdic acid colorimetric method was used to measure the ATP content in the ovarian tissue. Finally, the mitochondrial membrane potential of ovarian cells was detected with JC-1 dye. Results The cisplatin resulted in a decline of body weight, reduced ovarian weight significantly, and resulted in disorders of the extrous cycle. The follicles’ number decreased within the tissue’s stromal hyperplasia. Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed. However, Mfn2 was present in the cell’s cytoplasm in both groups. Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased. In addition, the ATP levels (35.2 ±5.7μmol/g) of the control group were significantly higher (13.5 ± 3.8 μmol/g). Lastly, an obvious impairment of mitochondrial function and structure was observed. Conclusion The intreperitoneal injection of cisplatin, when administered for 10 days, establishes a POF model. Thus, the above results suggest that lower expression of Mfn2 may be

  14. N-Formyl peptides drive mitochondrial damage associated molecular pattern induced neutrophil activation through ERK1/2 and P38 MAP kinase signalling pathways.

    PubMed

    Hazeldine, Jon; Hampson, Peter; Opoku, Francis Adusei; Foster, Mark; Lord, Janet M

    2015-01-01

    Traumatic injury results in a systemic inflammatory response syndrome (SIRS), a phenomenon characterised by the release of pro-inflammatory cytokines into the circulation and immune cell activation. Released from necrotic cells as a result of tissue damage, damage associated molecular patterns (DAMPs) are thought to initiate the SIRS response by activating circulating immune cells through surface expressed pathogen recognition receptors. Neutrophils, the most abundant leucocyte in human circulation, are heavily implicated in the initial immune response to traumatic injury and have been shown to elicit a robust functional response to DAMP stimulation. Here, we confirm that mitochondrial DAMPs (mtDAMPs) are potent activators of human neutrophils and show for the first time that signalling through the mitogen-activated-protein-kinases p38 and extracellular-signal-related-kinase 1/2 (ERK1/2) is essential for this response. At 40 and/or 100 μg/ml, mtDAMPs activated human neutrophils, indicated by a significant reduction in the surface expression of L-selectin, and triggered a number of functional responses from both resting and tumour necrosis factor-α primed neutrophils, which included reactive oxygen species (ROS) generation, degranulation, secretion of interleukin-8 and activation of p38 and ERK1/2 MAPKs. Pre-treatment of neutrophils with Cyclosporin H, a selective inhibitor of formyl peptide receptor-1 (FPR-1), significantly inhibited mtDAMP-induced L-selectin shedding as well as p38 and ERK1/2 activation, suggesting that N-formyl peptides are the main constituents driving mtDAMP-induced neutrophil activation. Indeed, no evidence of L-selectin shedding or p38 and ERK1/2 activation was observed in neutrophils challenged with mitochondrial DNA alone. Interestingly, pharmacological inhibition of p38 or ERK1/2 either alone or in combination significantly inhibited L-selectin shedding and IL-8 secretion by mtDAMP-challenged neutrophils, revealing for the first time

  15. Mitochondrial Turnover in the Heart

    PubMed Central

    Gustafsson, Åsa B.

    2010-01-01

    Mitochondrial quality control is increasingly recognized as an essential element in maintaining optimally functioning tissues. Mitochondrial quality control depends upon a balance between biogenesis and autophagic destruction. Mitochondrial dynamics (fusion and fission) allows for the redistribution of mitochondrial components. We speculate that this permits sorting of highly functional components into one end of a mitochondrion, while damaged components are segregated at the other end, to be jettisoned by asymmetric fission followed by selective mitophagy. Ischemic preconditioning requires autophagy/mitophagy, resulting in selective elimination of damaged mitochondria, leaving behind a population of robust mitochondria with a higher threshold for opening of the mitochondrial permeability transition pore. In this review we will consider the factors that regulate mitochondrial biogenesis and destruction, the machinery involved in both processes, and the biomedical consequences associated with altered mitochondrial turnover. PMID:21147177

  16. Mitochondrial ROS Induces Cardiac Inflammation via a Pathway through mtDNA Damage in a Pneumonia-Related Sepsis Model.

    PubMed

    Yao, Xiao; Carlson, Deborah; Sun, Yuxiao; Ma, Lisha; Wolf, Steven E; Minei, Joseph P; Zang, Qun S

    2015-01-01

    We have previously shown that mitochondria-targeted vitamin E (Mito-Vit-E), a mtROS specific antioxidant, improves cardiac performance and attenuates inflammation in a pneumonia-related sepsis model. In this study, we applied the same approaches to decipher the signaling pathway(s) of mtROS-dependent cardiac inflammation after sepsis. Sepsis was induced in Sprague Dawley rats by intratracheal injection of S. pneumoniae. Mito-Vit-E, vitamin E or vehicle was administered 30 minutes later. In myocardium 24 hours post-inoculation, Mito-Vit-E, but not vitamin E, significantly protected mtDNA integrity and decreased mtDNA damage. Mito-Vit-E alleviated sepsis-induced reduction in mitochondria-localized DNA repair enzymes including DNA polymerase γ, AP endonuclease, 8-oxoguanine glycosylase, and uracil-DNA glycosylase. Mito-Vit-E dramatically improved metabolism and membrane integrity in mitochondria, suppressed leakage of mtDNA into the cytoplasm, inhibited up-regulation of Toll-like receptor 9 (TLR9) pathway factors MYD88 and RAGE, and limited RAGE interaction with its ligand TFAM in septic hearts. Mito-Vit-E also deactivated NF-κB and caspase 1, reduced expression of the essential inflammasome component ASC, and decreased inflammatory cytokine IL-1β. In vitro, both Mito-Vit-E and TLR9 inhibitor OND-I suppressed LPS-induced up-regulation in MYD88, RAGE, ASC, active caspase 1, and IL-1β in cardiomyocytes. Since free mtDNA escaped from damaged mitochondria function as a type of DAMPs to stimulate inflammation through TLR9, these data together suggest that sepsis-induced cardiac inflammation is mediated, at least partially, through mtDNA-TLR9-RAGE. At last, Mito-Vit-E reduced the circulation of myocardial injury marker troponin-I, diminished apoptosis and amended morphology in septic hearts, suggesting that mitochondria-targeted antioxidants are a potential cardioprotective approach for sepsis. PMID:26448624

  17. Mitochondrial ROS Induces Cardiac Inflammation via a Pathway through mtDNA Damage in a Pneumonia-Related Sepsis Model

    PubMed Central

    Yao, Xiao; Carlson, Deborah; Sun, Yuxiao; Ma, Lisha; Wolf, Steven E.; Minei, Joseph P.; Zang, Qun S.

    2015-01-01

    We have previously shown that mitochondria-targeted vitamin E (Mito-Vit-E), a mtROS specific antioxidant, improves cardiac performance and attenuates inflammation in a pneumonia-related sepsis model. In this study, we applied the same approaches to decipher the signaling pathway(s) of mtROS-dependent cardiac inflammation after sepsis. Sepsis was induced in Sprague Dawley rats by intratracheal injection of S. pneumoniae. Mito-Vit-E, vitamin E or vehicle was administered 30 minutes later. In myocardium 24 hours post-inoculation, Mito-Vit-E, but not vitamin E, significantly protected mtDNA integrity and decreased mtDNA damage. Mito-Vit-E alleviated sepsis-induced reduction in mitochondria-localized DNA repair enzymes including DNA polymerase γ, AP endonuclease, 8-oxoguanine glycosylase, and uracil-DNA glycosylase. Mito-Vit-E dramatically improved metabolism and membrane integrity in mitochondria, suppressed leakage of mtDNA into the cytoplasm, inhibited up-regulation of Toll-like receptor 9 (TLR9) pathway factors MYD88 and RAGE, and limited RAGE interaction with its ligand TFAM in septic hearts. Mito-Vit-E also deactivated NF-κB and caspase 1, reduced expression of the essential inflammasome component ASC, and decreased inflammatory cytokine IL–1β. In vitro, both Mito-Vit-E and TLR9 inhibitor OND-I suppressed LPS-induced up-regulation in MYD88, RAGE, ASC, active caspase 1, and IL–1β in cardiomyocytes. Since free mtDNA escaped from damaged mitochondria function as a type of DAMPs to stimulate inflammation through TLR9, these data together suggest that sepsis-induced cardiac inflammation is mediated, at least partially, through mtDNA-TLR9-RAGE. At last, Mito-Vit-E reduced the circulation of myocardial injury marker troponin-I, diminished apoptosis and amended morphology in septic hearts, suggesting that mitochondria-targeted antioxidants are a potential cardioprotective approach for sepsis. PMID:26448624

  18. Methotrexate Promotes Platelet Apoptosis via JNK-Mediated Mitochondrial Damage: Alleviation by N-Acetylcysteine and N-Acetylcysteine Amide.

    PubMed

    Paul, Manoj; Hemshekhar, Mahadevappa; Thushara, Ram M; Sundaram, Mahalingam S; NaveenKumar, Somanathapura K; Naveen, Shivanna; Devaraja, Sannaningaiah; Somyajit, Kumar; West, Robert; Basappa; Nayaka, Siddaiah C; Zakai, Uzma I; Nagaraju, Ganesh; Rangappa, Kanchugarakoppal S; Kemparaju, Kempaiah; Girish, Kesturu S

    2015-01-01

    Thrombocytopenia in methotrexate (MTX)-treated cancer and rheumatoid arthritis (RA) patients connotes the interference of MTX with platelets. Hence, it seemed appealing to appraise the effect of MTX on platelets. Thereby, the mechanism of action of MTX on platelets was dissected. MTX (10 μM) induced activation of pro-apoptotic proteins Bid, Bax and Bad through JNK phosphorylation leading to ΔΨm dissipation, cytochrome c release and caspase activation, culminating in apoptosis. The use of specific inhibitor for JNK abrogates the MTX-induced activation of pro-apoptotic proteins and downstream events confirming JNK phosphorylation by MTX as a key event. We also demonstrate that platelet mitochondria as prime sources of ROS which plays a central role in MTX-induced apoptosis. Further, MTX induces oxidative stress by altering the levels of ROS and glutathione cycle. In parallel, the clinically approved thiol antioxidant N-acetylcysteine (NAC) and its derivative N-acetylcysteine amide (NACA) proficiently alleviate MTX-induced platelet apoptosis and oxidative damage. These findings underpin the dearth of research on interference of therapeutic drugs with platelets, despite their importance in human health and disease. Therefore, the use of antioxidants as supplementary therapy seems to be a safe bet in pathologies associated with altered platelet functions. PMID:26083398

  19. Methotrexate Promotes Platelet Apoptosis via JNK-Mediated Mitochondrial Damage: Alleviation by N-Acetylcysteine and N-Acetylcysteine Amide

    PubMed Central

    Paul, Manoj; Hemshekhar, Mahadevappa; Thushara, Ram M.; Sundaram, Mahalingam S.; NaveenKumar, Somanathapura K.; Naveen, Shivanna; Devaraja, Sannaningaiah; Somyajit, Kumar; West, Robert; Basappa; Nayaka, Siddaiah C.; Zakai, Uzma I.; Nagaraju, Ganesh; Rangappa, Kanchugarakoppal S.; Kemparaju, Kempaiah; Girish, Kesturu S.

    2015-01-01

    Thrombocytopenia in methotrexate (MTX)-treated cancer and rheumatoid arthritis (RA) patients connotes the interference of MTX with platelets. Hence, it seemed appealing to appraise the effect of MTX on platelets. Thereby, the mechanism of action of MTX on platelets was dissected. MTX (10 μM) induced activation of pro-apoptotic proteins Bid, Bax and Bad through JNK phosphorylation leading to ΔΨm dissipation, cytochrome c release and caspase activation, culminating in apoptosis. The use of specific inhibitor for JNK abrogates the MTX-induced activation of pro-apoptotic proteins and downstream events confirming JNK phosphorylation by MTX as a key event. We also demonstrate that platelet mitochondria as prime sources of ROS which plays a central role in MTX-induced apoptosis. Further, MTX induces oxidative stress by altering the levels of ROS and glutathione cycle. In parallel, the clinically approved thiol antioxidant N-acetylcysteine (NAC) and its derivative N-acetylcysteine amide (NACA) proficiently alleviate MTX-induced platelet apoptosis and oxidative damage. These findings underpin the dearth of research on interference of therapeutic drugs with platelets, despite their importance in human health and disease. Therefore, the use of antioxidants as supplementary therapy seems to be a safe bet in pathologies associated with altered platelet functions. PMID:26083398

  20. Mitochondrial dysfunction during sepsis.

    PubMed

    Azevedo, Luciano Cesar Pontes

    2010-09-01

    Sepsis and multiple organ failure remain leading causes of death in intensive care patients. Recent advances in our understanding of the pathophysiology of these syndromes include a likely prominent role for mitochondria. Patient studies have shown that the degree of mitochondrial dysfunction is related to the eventual outcome. Associated mechanisms include damage to mitochondria or inhibition of the electron transport chain enzymes by nitric oxide and other reactive oxygen species (the effects of which are amplified by co-existing tissue hypoxia), hormonal influences that decrease mitochondrial activity, and downregulation of mitochondrial protein expression. Notably, despite these findings, there is minimal cell death seen in most affected organs, and these organs generally regain reasonably normal function should the patient survive. It is thus plausible that multiple organ failure following sepsis may actually represent an adaptive state whereby the organs temporarily 'shut down' their normal metabolic functions in order to protect themselves from an overwhelming and prolonged insult. A decrease in energy supply due to mitochondrial inhibition or injury may trigger this hibernation/estivation-like state. Likewise, organ recovery may depend on restoration of normal mitochondrial respiration. Data from animal studies show histological recovery of mitochondria after a septic insult that precedes clinical improvement. Stimulation of mitochondrial biogenesis could offer a new therapeutic approach for patients in multi-organ failure. This review will cover basic aspects of mitochondrial function, mechanisms of mitochondrial dysfunction in sepsis, and approaches to prevent, mitigate or speed recovery from mitochondrial injury. PMID:20509844

  1. Twin Mitochondrial Sequence Analysis.

    PubMed

    Bouhlal, Yosr; Martinez, Selena; Gong, Henry; Dumas, Kevin; Shieh, Joseph T C

    2013-09-01

    When applying genome-wide sequencing technologies to disease investigation, it is increasingly important to resolve sequence variation in regions of the genome that may have homologous sequences. The human mitochondrial genome challenges interpretation given the potential for heteroplasmy, somatic variation, and homologous nuclear mitochondrial sequences (numts). Identical twins share the same mitochondrial DNA (mtDNA) from early life, but whether the mitochondrial sequence remains similar is unclear. We compared an adult monozygotic twin pair using high throughput-sequencing and evaluated variants with primer extension and mitochondrial pre-enrichment. Thirty-seven variants were shared between the twin individuals, and the variants were verified on the original genomic DNA. These studies support highly identical genetic sequence in this case. Certain low-level variant calls were of high quality and homology to the mitochondrial DNA, and they were further evaluated. When we assessed calls in pre-enriched mitochondrial DNA templates, we found that these may represent numts, which can be differentiated from mtDNA variation. We conclude that twin identity extends to mitochondrial DNA, and it is critical to differentiate between numts and mtDNA in genome sequencing, particularly since significant heteroplasmy could influence genome interpretation. Further studies on mtDNA and numts will aid in understanding how variation occurs and persists. PMID:24040623

  2. Comparison of intraplatelet reactive oxygen species, mitochondrial damage, and platelet apoptosis after implantation of three continuous flow left ventricular assist devices: HeartMate II, Jarvik 2000, and HeartWare.

    PubMed

    Mondal, Nandan K; Sorensen, Erik N; Feller, Erika D; Pham, Si M; Griffith, Bartley P; Wu, Zhongjun J

    2015-01-01

    Differences in device design may have an effect on platelet damage and associated clinical complications. We aimed to compare device-specific platelet functionality in 26 heart failure patients supported with three continuous-flow left ventricular assist devices: HeartMate II (n = 8), Jarvik 2000 (n = 9), and HeartWare (n = 9). Intraplatelet reactive oxygen species (ROS) generation, mitochondrial damage, and platelet apoptosis were compared between device types before and after the implantation at every week up to 1 month. Overall, the baseline characteristics, demographics, routine laboratory values were comparable between the three device groups. Intraplatelet ROS, mitochondrial damage, and platelet apoptosis significantly elevated in the HeartWare group in comparison with the other two device groups after implantation. The major bleeding, infections, systemic inflammatory response syndrome, and right ventricular failure were found to be more common among the HeartWare group than others. Intraplatelet ROS and platelet damage levels were returned to baseline in both the HeartMate II and the Jarvik groups, whereas in HeartWare group they remained elevated. The patients with the Jarvik and the HeartMate II experienced less clinical complications and the platelet functionality is not compromised by these devices. Data from this study suggests that the continuous-flow left ventricular assist devices design may exert different effects on platelet function. PMID:25757140

  3. Methamphetamine causes acute hyperthermia-dependent liver damage.

    PubMed

    Halpin, Laura E; Gunning, William T; Yamamoto, Bryan K

    2013-10-01

    Methamphetamine-induced neurotoxicity has been correlated with damage to the liver but this damage has not been extensively characterized. Moreover, the mechanism by which the drug contributes to liver damage is unknown. This study characterizes the hepatocellular toxicity of methamphetamine and examines if hyperthermia contributes to this liver damage. Livers from methamphetamine-treated rats were examined using electron microscopy and hematoxylin and eosin staining. Methamphetamine increased glycogen stores, mitochondrial aggregation, microvesicular lipid, and hydropic change. These changes were diffuse throughout the hepatic lobule, as evidenced by a lack of hematoxylin and eosin staining. To confirm if these changes were indicative of damage, serum aspartate and alanine aminotransferase were measured. The functional significance of methamphetamine-induced liver damage was also examined by measuring plasma ammonia. To examine the contribution of hyperthermia to this damage, methamphetamine-treated rats were cooled during and after drug treatment by cooling their external environment. Serum aspartate and alanine aminotransferase, as well as plasma ammonia were increased concurrently with these morphologic changes and were prevented when methamphetamine-induced hyperthermia was blocked. These findings support that methamphetamine produces changes in hepatocellular morphology and damage persisting for at least 24 h after drug exposure. At this same time point, methamphetamine treatment significantly increases plasma ammonia concentrations, consistent with impaired ammonia metabolism and functional liver damage. Methamphetamine-induced hyperthermia contributes significantly to the persistent liver damage and increases in peripheral ammonia produced by the drug. PMID:25505562

  4. Methamphetamine causes acute hyperthermia-dependent liver damage

    PubMed Central

    Halpin, Laura E; Gunning, William T; Yamamoto, Bryan K

    2013-01-01

    Methamphetamine-induced neurotoxicity has been correlated with damage to the liver but this damage has not been extensively characterized. Moreover, the mechanism by which the drug contributes to liver damage is unknown. This study characterizes the hepatocellular toxicity of methamphetamine and examines if hyperthermia contributes to this liver damage. Livers from methamphetamine-treated rats were examined using electron microscopy and hematoxylin and eosin staining. Methamphetamine increased glycogen stores, mitochondrial aggregation, microvesicular lipid, and hydropic change. These changes were diffuse throughout the hepatic lobule, as evidenced by a lack of hematoxylin and eosin staining. To confirm if these changes were indicative of damage, serum aspartate and alanine aminotransferase were measured. The functional significance of methamphetamine-induced liver damage was also examined by measuring plasma ammonia. To examine the contribution of hyperthermia to this damage, methamphetamine-treated rats were cooled during and after drug treatment by cooling their external environment. Serum aspartate and alanine aminotransferase, as well as plasma ammonia were increased concurrently with these morphologic changes and were prevented when methamphetamine-induced hyperthermia was blocked. These findings support that methamphetamine produces changes in hepatocellular morphology and damage persisting for at least 24 h after drug exposure. At this same time point, methamphetamine treatment significantly increases plasma ammonia concentrations, consistent with impaired ammonia metabolism and functional liver damage. Methamphetamine-induced hyperthermia contributes significantly to the persistent liver damage and increases in peripheral ammonia produced by the drug. PMID:25505562

  5. Mitochondrial DNA, mitochondrial dysfunction, and cardiac manifestations.

    PubMed

    Lee, Sung Ryul; Kim, Nari; Noh, Yeonhee; Xu, Zhelong; Ko, Kyung Soo; Rhee, Byoung Doo; Han, Jin

    2016-01-01

    Mitochondria, the powerhouses of cells, have their own DNA (mtDNA). They regulate the transport of metabolites and ions, which determine cell physiology, survival, and death. Mitochondrial dysfunction, including impaired oxidative phosphorylation, preferentially affects heart function via imbalance of energy supply and demand. Recently, mitochondrial mutations and associated mitochondrial dysfunction were suggested as a causal factor of cardiac manifestations. Oxidative stress largely influences mtDNA stability due to oxidative modifications of mtDNA. Furthermore, the continuous replicative state of mtDNA and presence of minimal nucleoid structure render mitochondria vulnerable to oxidative damage and subsequent mutations, which impair mitochondrial functions. However, the occurrence of mtDNA heteroplasmy in the same mitochondrion or cell and presence of nuclear DNA-encoded mtDNA repair systems raise questions regarding whether oxidative stress-mediated mtDNA mutations are the major driving force in accumulation of mtDNA mutations. Here, we address the possible causes of mitochondrial DNA mutations and their involvement in cardiac manifestations. Current strategies for treatment related to mitochondrial mutations and/or dysfunction in cardiac manifestations are briefly discussed. PMID:27100514

  6. Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit.

    PubMed

    Tran, Lee; Hanavan, Paul D; Campbell, Latoya E; De Filippis, Elena; Lake, Douglas F; Coletta, Dawn K; Roust, Lori R; Mandarino, Lawrence J; Carroll, Chad C; Katsanos, Christos S

    2016-01-01

    Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = - 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish

  7. Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit

    PubMed Central

    Tran, Lee; Hanavan, Paul D.; Campbell, Latoya E.; De Filippis, Elena; Lake, Douglas F.; Coletta, Dawn K.; Roust, Lori R.; Mandarino, Lawrence J.; Carroll, Chad C.; Katsanos, Christos S.

    2016-01-01

    Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = – 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish

  8. Exposure to Heavy Ion Radiation Induces Persistent Oxidative Stress in Mouse Intestine

    PubMed Central

    Datta, Kamal; Suman, Shubhankar; Kallakury, Bhaskar V. S.; Fornace, Albert J.

    2012-01-01

    Ionizing radiation-induced oxidative stress is attributed to generation of reactive oxygen species (ROS) due to radiolysis of water molecules and is short lived. Persistent oxidative stress has also been observed after radiation exposure and is implicated in the late effects of radiation. The goal of this study was to determine if long-term oxidative stress in freshly isolated mouse intestinal epithelial cells (IEC) is dependent on radiation quality at a dose relevant to fractionated radiotherapy. Mice (C57BL/6J; 6 to 8 weeks; female) were irradiated with 2 Gy of γ-rays, a low-linear energy transfer (LET) radiation, and intestinal tissues and IEC were collected 1 year after radiation exposure. Intracellular ROS, mitochondrial function, and antioxidant activity in IEC were studied by flow cytometry and biochemical assays. Oxidative DNA damage, cell death, and mitogenic activity in IEC were assessed by immunohistochemistry. Effects of γ radiation were compared to 56Fe radiation (iso-toxic dose: 1.6 Gy; energy: 1000 MeV/nucleon; LET: 148 keV/µm), we used as representative of high-LET radiation, since it's one of the important sources of high Z and high energy (HZE) radiation in cosmic rays. Radiation quality affected the level of persistent oxidative stress with higher elevation of intracellular ROS and mitochondrial superoxide in high-LET 56Fe radiation compared to unirradiated controls and γ radiation. NADPH oxidase activity, mitochondrial membrane damage, and loss of mitochondrial membrane potential were greater in 56Fe-irradiated mice. Compared to γ radiation oxidative DNA damage was higher, cell death ratio was unchanged, and mitotic activity was increased after 56Fe radiation. Taken together our results indicate that long-term functional dysregulation of mitochondria and increased NADPH oxidase activity are major contributing factors towards heavy ion radiation-induced persistent oxidative stress in IEC with potential for neoplastic transformation. PMID

  9. Methods for Efficient Elimination of Mitochondrial DNA from Cultured Cells

    PubMed Central

    Spadafora, Domenico; Kozhukhar, Nataliya; Chouljenko, Vladimir N.; Kousoulas, Konstantin G.; Alexeyev, Mikhail F.

    2016-01-01

    Here, we document that persistent mitochondria DNA (mtDNA) damage due to mitochondrial overexpression of the Y147A mutant uracil-N-glycosylase as well as mitochondrial overexpression of bacterial Exonuclease III or Herpes Simplex Virus protein UL12.5M185 can induce a complete loss of mtDNA (ρ0 phenotype) without compromising the viability of cells cultured in media supplemented with uridine and pyruvate. Furthermore, we use these observations to develop rapid, sequence-independent methods for the elimination of mtDNA, and demonstrate utility of these methods for generating ρ0 cells of human, mouse and rat origin. We also demonstrate that ρ0 cells generated by each of these three methods can serve as recipients of mtDNA in fusions with enucleated cells. PMID:27136098

  10. A Heart That Beats for 500 Years: Age-Related Changes in Cardiac Proteasome Activity, Oxidative Protein Damage and Expression of Heat Shock Proteins, Inflammatory Factors, and Mitochondrial Complexes in Arctica islandica, the Longest-Living Noncolonial Animal

    PubMed Central

    Sosnowska, Danuta; Richardson, Chris; Sonntag, William E.; Csiszar, Anna; Ridgway, Iain

    2014-01-01

    Study of negligibly senescent animals may provide clues that lead to better understanding of the cardiac aging process. To elucidate mechanisms of successful cardiac aging, we investigated age-related changes in proteasome activity, oxidative protein damage and expression of heat shock proteins, inflammatory factors, and mitochondrial complexes in the heart of the ocean quahog Arctica islandica, the longest-lived noncolonial animal (maximum life span potential: 508 years). We found that in the heart of A. islandica the level of oxidatively damaged proteins did not change significantly up to 120 years of age. No significant aging-induced changes were observed in caspase-like and trypsin-like proteasome activity. Chymotrypsin-like proteasome activity showed a significant early-life decline, then it remained stable for up to 182 years. No significant relationship was observed between the extent of protein ubiquitination and age. In the heart of A. islandica, an early-life decline in expression of HSP90 and five mitochondrial electron transport chain complexes was observed. We found significant age-related increases in the expression of three cytokine-like mediators (interleukin-6, interleukin-1β, and tumor necrosis factor-α) in the heart of A. islandica. Collectively, in extremely long-lived molluscs, maintenance of protein homeostasis likely contributes to the preservation of cardiac function. Our data also support the concept that low-grade chronic inflammation in the cardiovascular system is a universal feature of the aging process, which is also manifest in invertebrates. PMID:24347613

  11. Mitochondrial disease in pregnancy: a systematic review

    PubMed Central

    Say, R E; Whittaker, R G; Turnbull, H E; McFarland, R; Taylor, R W; Turnbull, D M

    2011-01-01

    Mitochondrial diseases are heterogeneous in clinical presentation and genotype. The incidence of known pathogenic mitochondrial DNA mutations in the general population is 1 in 500. Little is known about the implications of pregnancy for women with mitochondrial disease. We undertook a systematic review of the literature on mitochondrial disease in pregnancy. Ten case reports were identified. The most common complications were threatened preterm labour (5 women) and preeclampsia (4 women). Two women experienced magnesium sulphate toxicity. Pregnancy had a varied effect on mitochondrial disease with some women being asymptomatic; others developing mild symptoms such as exercise intolerance or muscle weakness which resolved postnatally; and others developed more serious, persistent symptoms such as symptomatic Wolff–Parkinson–White syndrome, persistent paraesthesia and focal segmental glomerulosclerosis. Women with mitochondrial disease appear to be at increased risk of complications during pregnancy and labour but further prospective cohort studies are needed.

  12. Mitochondrial Dynamics in Diabetic Cardiomyopathy

    PubMed Central

    Galloway, Chad A.

    2015-01-01

    Abstract Significance: Cardiac function is energetically demanding, reliant on efficient well-coupled mitochondria to generate adenosine triphosphate and fulfill the cardiac demand. Predictably then, mitochondrial dysfunction is associated with cardiac pathologies, often related to metabolic disease, most commonly diabetes. Diabetic cardiomyopathy (DCM), characterized by decreased left ventricular function, arises independently of coronary artery disease and atherosclerosis. Dysregulation of Ca2+ handling, metabolic changes, and oxidative stress are observed in DCM, abnormalities reflected in alterations in mitochondrial energetics. Cardiac tissue from DCM patients also presents with altered mitochondrial morphology, suggesting a possible role of mitochondrial dynamics in its pathological progression. Recent Advances: Abnormal mitochondrial morphology is associated with pathologies across diverse tissues, suggesting that this highly regulated process is essential for proper cell maintenance and physiological homeostasis. Highly structured cardiac myofibers were hypothesized to limit alterations in mitochondrial morphology; however, recent work has identified morphological changes in cardiac tissue, specifically in DCM. Critical Issues: Mitochondrial dysfunction has been reported independently from observations of altered mitochondrial morphology in DCM. The temporal relationship and causative nature between functional and morphological changes of mitochondria in the establishment/progression of DCM is unclear. Future Directions: Altered mitochondrial energetics and morphology are not only causal for but also consequential to reactive oxygen species production, hence exacerbating oxidative damage through reciprocal amplification, which is integral to the progression of DCM. Therefore, targeting mitochondria for DCM will require better mechanistic characterization of morphological distortion and bioenergetic dysfunction. Antioxid. Redox Signal. 22, 1545–1562. PMID

  13. Mitochondrial Cardiomyopathies

    PubMed Central

    El-Hattab, Ayman W.; Scaglia, Fernando

    2016-01-01

    Mitochondria are found in all nucleated human cells and perform various essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA), whereas more than 99% of them are encoded by nuclear DNA (nDNA). Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs for various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20–40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular non-compaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain complexes subunits and their assembly factors, mitochondrial transfer RNAs, ribosomal RNAs, ribosomal proteins, translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia. PMID:27504452

  14. Mitochondrial vasculopathy.

    PubMed

    Finsterer, Josef; Zarrouk-Mahjoub, Sinda

    2016-05-26

    Mitochondrial disorders (MIDs) are usually multisystem disorders (mitochondrial multiorgan disorder syndrome) either on from onset or starting at a point during the disease course. Most frequently affected tissues are those with a high oxygen demand such as the central nervous system, the muscle, endocrine glands, or the myocardium. Recently, it has been shown that rarely also the arteries may be affected (mitochondrial arteriopathy). This review focuses on the type, diagnosis, and treatment of mitochondrial vasculopathy in MID patients. A literature search using appropriate search terms was carried out. Mitochondrial vasculopathy manifests as either microangiopathy or macroangiopathy. Clinical manifestations of mitochondrial microangiopathy include leukoencephalopathy, migraine-like headache, stroke-like episodes, or peripheral retinopathy. Mitochondrial macroangiopathy manifests as atherosclerosis, ectasia of arteries, aneurysm formation, dissection, or spontaneous rupture of arteries. The diagnosis relies on the documentation and confirmation of the mitochondrial metabolic defect or the genetic cause after exclusion of non-MID causes. Treatment is not at variance compared to treatment of vasculopathy due to non-MID causes. Mitochondrial vasculopathy exists and manifests as micro- or macroangiopathy. Diagnosing mitochondrial vasculopathy is crucial since appropriate treatment may prevent from severe complications. PMID:27231520

  15. Mitochondrial vasculopathy

    PubMed Central

    Finsterer, Josef; Zarrouk-Mahjoub, Sinda

    2016-01-01

    Mitochondrial disorders (MIDs) are usually multisystem disorders (mitochondrial multiorgan disorder syndrome) either on from onset or starting at a point during the disease course. Most frequently affected tissues are those with a high oxygen demand such as the central nervous system, the muscle, endocrine glands, or the myocardium. Recently, it has been shown that rarely also the arteries may be affected (mitochondrial arteriopathy). This review focuses on the type, diagnosis, and treatment of mitochondrial vasculopathy in MID patients. A literature search using appropriate search terms was carried out. Mitochondrial vasculopathy manifests as either microangiopathy or macroangiopathy. Clinical manifestations of mitochondrial microangiopathy include leukoencephalopathy, migraine-like headache, stroke-like episodes, or peripheral retinopathy. Mitochondrial macroangiopathy manifests as atherosclerosis, ectasia of arteries, aneurysm formation, dissection, or spontaneous rupture of arteries. The diagnosis relies on the documentation and confirmation of the mitochondrial metabolic defect or the genetic cause after exclusion of non-MID causes. Treatment is not at variance compared to treatment of vasculopathy due to non-MID causes. Mitochondrial vasculopathy exists and manifests as micro- or macroangiopathy. Diagnosing mitochondrial vasculopathy is crucial since appropriate treatment may prevent from severe complications. PMID:27231520

  16. Mitochondrial Cardiomyopathies.

    PubMed

    El-Hattab, Ayman W; Scaglia, Fernando

    2016-01-01

    Mitochondria are found in all nucleated human cells and perform various essential functions, including the generation of cellular energy. Mitochondria are under dual genome control. Only a small fraction of their proteins are encoded by mitochondrial DNA (mtDNA), whereas more than 99% of them are encoded by nuclear DNA (nDNA). Mutations in mtDNA or mitochondria-related nDNA genes result in mitochondrial dysfunction leading to insufficient energy production required to meet the needs for various organs, particularly those with high energy requirements, including the central nervous system, skeletal and cardiac muscles, kidneys, liver, and endocrine system. Because cardiac muscles are one of the high energy demanding tissues, cardiac involvement occurs in mitochondrial diseases with cardiomyopathies being one of the most frequent cardiac manifestations found in these disorders. Cardiomyopathy is estimated to occur in 20-40% of children with mitochondrial diseases. Mitochondrial cardiomyopathies can vary in severity from asymptomatic status to severe manifestations including heart failure, arrhythmias, and sudden cardiac death. Hypertrophic cardiomyopathy is the most common type; however, mitochondrial cardiomyopathies might also present as dilated, restrictive, left ventricular non-compaction, and histiocytoid cardiomyopathies. Cardiomyopathies are frequent manifestations of mitochondrial diseases associated with defects in electron transport chain complexes subunits and their assembly factors, mitochondrial transfer RNAs, ribosomal RNAs, ribosomal proteins, translation factors, mtDNA maintenance, and coenzyme Q10 synthesis. Other mitochondrial diseases with cardiomyopathies include Barth syndrome, Sengers syndrome, TMEM70-related mitochondrial complex V deficiency, and Friedreich ataxia. PMID:27504452

  17. Persistence of Space Radiation-Induced Cytogenetic Damage in the Blood Lymphocytes of Astronauts and the Effects of Repeat Long Duration Space Missions

    NASA Technical Reports Server (NTRS)

    George, Kerry A.; Cucinotta, Francis A.

    2009-01-01

    The yield of chromosome damage in astronauts blood lymphocytes has been shown to increase after long duration space missions of a few months or more. This provides a useful in vivo measurement of space radiation induced damage that takes into account individual radiosensitivity and considers the influence of microgravity and other stress conditions. We present our latest follow-up analyses of chromosome damage in astronauts blood lymphocytes assessed by fluorescence in situ hybridization (FISH) chromosome painting and collected at various times, from directly after return from space to several years after flight. For most individuals the analysis of individual time-courses for translocations revealed a temporal decline of yields with different half-lives. Dose was derived from frequencies of chromosome exchanges using preflight calibration curves, and estimates derived from samples collected a few days after return to earth lie within the range expected from physical dosimetry. However, a temporal decline in yields may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure. Limited data on three individuals who have participated in repeat long duration space flights indicates a lack of correlation between time in space and translocation yields, and show a possible adaptive response to space radiation exposure.

  18. Novel Nitrobenzazolo[3,2-a]quinolinium Salts Induce Cell Death through a Mechanism Involving DNA Damage, Cell Cycle Changes, and Mitochondrial Permeabilization

    PubMed Central

    Vélez, Christian; Cox, Osvaldo; Rosado-Berrios, Carlos A.; Molina, Dennise; Arroyo, Luz; Carro, Sujey; Filikov, Anton; Kumar, Vineet; Malhotra, Sanjay V.; Cordero, Marisol; Zayas, Beatriz

    2014-01-01

    This study reports the capacity of three nitro substituted benzazolo[3,2-a]quinolinium salts NBQs: NBQ 95 (NSC-763304), NBQ 38 (NSC 763305), and NBQ 97 (NSC-763306) as potential antitumor agents. NBQ’s are unnatural alkaloids possessing a positive charge that could facilitate interaction with cell organelles. The anticancer activities of these compounds were evaluated through the National Cancer Institute (NCI) 60 cell line screening which represents diverse histologies. The screening was performed at 10 µM on all cell lines. Results from the NCI screening indicated cytotoxicity activity on six cell lines. In order to explore a possible mechanism of action, a detailed biological activity study of NBQ 95 and NBQ 38 was performed on A431 human epidermoid carcinoma cells to determine an apoptotic pathway involving, cell cycle changes, DNA fragmentation, mutations, mitochondrial membrane permeabilization and caspases activation. DNA fragmentation, cell cycle effects, mutagenesis, mitochondrial permeabilization and activation of caspases were determined by fluorimetry and differential imaging. Our data showed that A431 growth was inhibited with an average IC50 of 30 µM. In terms of the mechanism, these compounds interacted with DNA causing fragmentation and cell cycle arrest at sub G0/G1 stage. Mutagenesis was higher for NBQ 38 and moderate for NBQ 95 Mitochon-drial permeabilization was observed with NBQ 38 and slightly for NBQ 95. Both compounds caused activation of Caspases 3 and 7 suggesting an apoptotic cell death pathway through an intrinsic mechanism. This study reports evidence of the toxicity of these novel compounds with overlapping structural and mechanistic similarities to ellipticine, a known anti-tumor compound. PMID:25243104

  19. Mechanism of mitochondrial permeability transition pore induction and damage in the pancreas: inhibition prevents acute pancreatitis by protecting production of ATP

    PubMed Central

    Mukherjee, Rajarshi; Mareninova, Olga A; Odinokova, Irina V; Huang, Wei; Murphy, John; Chvanov, Michael; Javed, Muhammad A; Wen, Li; Booth, David M; Cane, Matthew C; Awais, Muhammad; Gavillet, Bruno; Pruss, Rebecca M; Schaller, Sophie; Molkentin, Jeffery D; Tepikin, Alexei V; Petersen, Ole H; Pandol, Stephen J; Gukovsky, Ilya; Criddle, David N; Gukovskaya, Anna S; Sutton, Robert

    2016-01-01

    Objective Acute pancreatitis is caused by toxins that induce acinar cell calcium overload, zymogen activation, cytokine release and cell death, yet is without specific drug therapy. Mitochondrial dysfunction has been implicated but the mechanism not established. Design We investigated the mechanism of induction and consequences of the mitochondrial permeability transition pore (MPTP) in the pancreas using cell biological methods including confocal microscopy, patch clamp technology and multiple clinically representative disease models. Effects of genetic and pharmacological inhibition of the MPTP were examined in isolated murine and human pancreatic acinar cells, and in hyperstimulation, bile acid, alcoholic and choline-deficient, ethionine-supplemented acute pancreatitis. Results MPTP opening was mediated by toxin-induced inositol trisphosphate and ryanodine receptor calcium channel release, and resulted in diminished ATP production, leading to impaired calcium clearance, defective autophagy, zymogen activation, cytokine production, phosphoglycerate mutase 5 activation and necrosis, which was prevented by intracellular ATP supplementation. When MPTP opening was inhibited genetically or pharmacologically, all biochemical, immunological and histopathological responses of acute pancreatitis in all four models were reduced or abolished. Conclusions This work demonstrates the mechanism and consequences of MPTP opening to be fundamental to multiple forms of acute pancreatitis and validates the MPTP as a drug target for this disease. PMID:26071131

  20. Contribution of nano-copper particles to in vivo liver dysfunction and cellular damage: role of IκBα/NF-κB, MAPKs and mitochondrial signal.

    PubMed

    Manna, Prasenjit; Ghosh, Manoranjan; Ghosh, Jyotirmoy; Das, Joydeep; Sil, Parames C

    2012-02-01

    The present study investigated the oxidative stress responsive cell signaling in nano-copper-induced hepatic dysfunction and cell death. Exposure to nano-copper (18 nm) dose-dependently (200-600 mg/kg bw) reduced the hepatic index, caused oxidative stress and led to hepatic dysfunction. Nano-copper burden also increased the transcriptional activity of NF-κB, up-regulated the expression of phosphorylated p38, ERK1/2 and caused the reciprocal regulation of Bcl-2 family proteins, disruption of mitochondrial membrane potential, release of cytochrome C, formation of apoptosome and activation of caspase 3. DAPI staining, immunofluorescence study, FACS analysis and histological findings also support this observation. Soluble copper (Cu(+2), 110 mg/kg bw)-exposed animals were used as a positive control. Different doses of particulate and soluble forms were used in the study because of different LD(50) values. The results suggest that nano-copper induces hepatic dysfunction and cell death via the oxidative stress-dependent signaling cascades and mitochondrial event. PMID:21319953

  1. The mitochondrial unfolded protein response - synchronizing genomes

    PubMed Central

    Jovaisaite, Virginija; Auwerx, Johan

    2014-01-01

    Maintenance of the mitochondrial proteome is performed primarily by chaperones, which fold and assemble proteins, and by proteases, which degrade excess damaged proteins. Upon various types of mitochondrial stress, triggered genetically or pharmacologically, dysfunction of the proteome is sensed and communicated to the nucleus, where an extensive transcriptional program, aimed to repair the damage, is activated. This feedback loop, termed the mitochondrial unfolded protein response (UPRmt), synchronizes the activity of the mitochondrial and nuclear genomes and as such ensures the quality of the mitochondrial proteome. Here we review the recent advances in the UPRmt field and discuss its induction, signaling, communication with the other mitochondrial and major cellular regulatory pathways and its potential implications on health and lifespan. PMID:25543897

  2. Mitochondrial Diseases

    PubMed Central

    Lee, Young-Mock

    2012-01-01

    Mitochondria contain the respiratory chain enzyme complexes that carry out oxidative phosphorylation and produce the main part of cellular energy in the form of ATP. Although several proteins related with signalling, assembling, transporting, and enzymatic function can be impaired in mitochondrial diseases, most frequently the activity of the respiratory chain protein complexes is primarily or secondarily affected, leading to impaired oxygen utilization and reduced energy production. Mitochondrial diseases usually show a chronic, slowly progressive course and present with multiorgan involvement with varying onset between birth and late adulthood. Neuromuscular system is frequently affected in mitochondrial diseases. Although there is actually no specific therapy and cure for mitochondrial diseases, the understanding of the pathophysiology may further facilitate the diagnostic approach and open perspectives to future in mitochondrial diseases. PMID:24649452

  3. [Persistent diarrhea

    PubMed

    Andrade, J A; Moreira, C; Fagundes Neto, U

    2000-07-01

    INTRODUCTION: Persistent diarrhea has high impact on infantile morbidity and mortality rates in developing countries. Several studies have shown that 3 to 20% of acute diarrheal episodes in children under 5 years of age become persistent. DEFINITION: Persistent diarrhea is defined as an episode that lasts more than 14 days. ETIOLOGY: The most important agents isolated in persistent diarrhea are: Enteropathogenic E. coli (EPEC), Salmonella, Enteroaggregative E. coli (EAEC), Klebisiella and Cryptosporidium. CLINICAL ASPECTS: In general, the clinical characteristics of patients with persistent diarrhea do not change with the pathogenic agent. Persistent diarrhea seems to represent the final result of a several insults a infant suffers that predisposes to a more severe episode of diarrhea due to a combination of host factors and high rates of enviromental contamination. Therefore, efforts should be made to promptly treat all episodes of diarrhea with apropriate follow-up. THERAPY: The aim of the treatment is to restore hydroelectrolytic deficits and to replace losses until the diarrheal ceases. It is possible in the majority of the cases, using oral rehydration therapy and erly an appropriate type of diet. PREVENTION: It is imperative that management strategies also focus on preventive aspects. The most effective diarrheal prevention strategy in young infants worldwide is promotion of exclusive breast feeding. PMID:14676915

  4. Increased Selectivity towards Cytoplasmic versus Mitochondrial Ribosome Confers Improved Efficiency of Synthetic Aminoglycosides in Fixing Damaged Genes: A Strategy for Treatment of Genetic Diseases Caused by Nonsense Mutations

    PubMed Central

    Kandasamy, Jeyakumar; Atia-Glikin, Dana; Shulman, Eli; Shapira, Katya; Shavit, Michal; Belakhov, Valery; Baasov, Timor

    2012-01-01

    Compelling evidence is now available that gentamicin and geneticin (G418) can induce mammalian ribosome to suppress disease-causing nonsense mutations and partially restore the expression of functional proteins. However, toxicity and relative lack of efficacy at subtoxic doses limit the use of gentamicin for suppression therapy. Although G418 exhibits strongest activity, it is very cytotoxic even at low doses. We describe here the first systematic development of the novel aminoglycoside (S)-11 exhibiting similar in vitro and ex vivo activity to that of G418, while its cell toxicity is significantly lower than those of gentamicin and G418. Using a series of biochemical assays, we provide proof of principle that antibacterial activity and toxicity of aminoglycosides can be dissected from their suppression activity. The data further indicate that the increased specificity towards cytoplasmic ribosome correlates with the increased activity, and that the decreased specificity towards mitochondrial ribosome confers to the lowered cytotoxicity. PMID:23148581

  5. Mitochondrial cytopathies.

    PubMed

    El-Hattab, Ayman W; Scaglia, Fernando

    2016-09-01

    Mitochondria are found in all nucleated human cells and perform a variety of essential functions, including the generation of cellular energy. Most of mitochondrial proteins are encoded by the nuclear DNA (nDNA) whereas a very small fraction is encoded by the mitochondrial DNA (mtDNA). Mutations in mtDNA or mitochondria-related nDNA genes can result in mitochondrial dysfunction which leads to a wide range of cellular perturbations including aberrant calcium homeostasis, excessive reactive oxygen species production, dysregulated apoptosis, and insufficient energy generation to meet the needs of various organs, particularly those with high energy demand. Impaired mitochondrial function in various tissues and organs results in the multi-organ manifestations of mitochondrial diseases including epilepsy, intellectual disability, skeletal and cardiac myopathies, hepatopathies, endocrinopathies, and nephropathies. Defects in nDNA genes can be inherited in an autosomal or X-linked manners, whereas, mtDNA is maternally inherited. Mitochondrial diseases can result from mutations of nDNA genes encoding subunits of the electron transport chain complexes or their assembly factors, proteins associated with the mitochondrial import or networking, mitochondrial translation factors, or proteins involved in mtDNA maintenance. MtDNA defects can be either point mutations or rearrangements. The diagnosis of mitochondrial disorders can be challenging in many cases and is based on clinical recognition, biochemical screening, histopathological studies, functional studies, and molecular genetic testing. Currently, there are no satisfactory therapies available for mitochondrial disorders that significantly alter the course of the disease. Therapeutic options include symptomatic treatment, cofactor supplementation, and exercise. PMID:26996063

  6. Mitochondrial oxidative stress in aging and healthspan

    PubMed Central

    2014-01-01

    The free radical theory of aging proposes that reactive oxygen species (ROS)-induced accumulation of damage to cellular macromolecules is a primary driving force of aging and a major determinant of lifespan. Although this theory is one of the most popular explanations for the cause of aging, several experimental rodent models of antioxidant manipulation have failed to affect lifespan. Moreover, antioxidant supplementation clinical trials have been largely disappointing. The mitochondrial theory of aging specifies more particularly that mitochondria are both the primary sources of ROS and the primary targets of ROS damage. In addition to effects on lifespan and aging, mitochondrial ROS have been shown to play a central role in healthspan of many vital organ systems. In this article we review the evidence supporting the role of mitochondrial oxidative stress, mitochondrial damage and dysfunction in aging and healthspan, including cardiac aging, age-dependent cardiovascular diseases, skeletal muscle aging, neurodegenerative diseases, insulin resistance and diabetes as well as age-related cancers. The crosstalk of mitochondrial ROS, redox, and other cellular signaling is briefly presented. Potential therapeutic strategies to improve mitochondrial function in aging and healthspan are reviewed, with a focus on mitochondrial protective drugs, such as the mitochondrial antioxidants MitoQ, SkQ1, and the mitochondrial protective peptide SS-31. PMID:24860647

  7. Mitochondrial encephalomyopathies.

    PubMed

    Lombes, A; Bonilla, E; Dimauro, S

    1989-01-01

    Increasingly numerous studies are being devoted to mitochondrial diseases, notably those which involve the neuromuscular system. Our knowledge and understanding of these diseases is progressing rapidly. We owe to Luft et al. (1962) the first description of this type of diseases. Their patient, a woman, presented with clinical symptoms suggestive of mitochondrial dysfunction, major histological abnormalities of skeletal muscle mitochondria and defective oxidative phosphorylation coupling clearly demonstrated in mitochondria isolated from muscle. This clinical, histological and biochemical triad led to the definition of mitochondrial myopathies. Subsequently, the triad was seldom encountered, and most mitochondrial myopathies were primarily defined by the presence of morphological abnormalities of muscle mitochondria. This review deals with the morphological, clinical, biochemical and genetic aspects of mitochondrial encephalomyopathies. The various morphological abnormalities of mitochondria are described. These are not specific of any particular disease. They may be present in some non-mitochondrial diseases and may be lacking in diseases due to specific defects of mitochondrial enzymes (e.g. carnitine palmityl-transferase or pyruvate dehydrogenase). The clinical classification of mitochondrial encephalomyopathies is discussed. There are two main schools of thought: the "lumpers" do not recognize specific syndromes within the spectrum of mitochondrial "cytopathies", the "splitters" try to identify specific syndromes while recognizing the existence of borderline cases. The following syndromes are described: chronic progressive external ophthalmoplegia (CPEO), Kearns-Sayre syndrome (KSS), MERRF syndrome (myoclonic epilepsy with ragged-red fibers), MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) and Leigh and Alpers syndromes. The biochemical classification comprises five types of abnormalities: defects of transport

  8. Genetics Home Reference: mitochondrial neurogastrointestinal encephalopathy disease

    MedlinePlus

    ... modification) is used as a building block of DNA . Thymidine phosphorylase breaks down thymidine into smaller molecules, ... molecule is damaging to a particular kind of DNA known as mitochondrial DNA or mtDNA. Mitochondria are ...

  9. Genetics Home Reference: mitochondrial complex III deficiency

    MedlinePlus

    ... species, which are harmful molecules that can damage DNA and tissues. MT-CYB and BCS1L gene mutations ... genes, the MT-CYB gene is found in DNA located in mitochondria, called mitochondrial DNA (mtDNA). This ...

  10. Mitochondrial DNA.

    ERIC Educational Resources Information Center

    Wright, Russell G.; Bottino, Paul J.

    1986-01-01

    Provides background information for teachers on mitochondrial DNA, pointing out that it may have once been a free-living organism. Includes a ready-to-duplicate exercise titled "Using Microchondrial DNA to Measure Evolutionary Distance." (JN)

  11. Mitochondrial Myopathies

    MedlinePlus

    ... line and are therefore called the electron transport chain, and complex V actually churns out ATP, so ... coQ10 , is a component of the electron transport chain, which uses oxygen to manufacture ATP. Some mitochondrial ...

  12. Mitochondrial Diseases

    MedlinePlus

    ... in your body tissues. If you have a metabolic disorder, something goes wrong with this process. Mitochondrial diseases are a group of metabolic disorders. Mitochondria are small structures that produce energy in ...

  13. Mitochondrial Myopathy

    MedlinePlus

    ... with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes. The symptoms of ... riboflavin, coenzyme Q, and carnitine (a specialized amino acid) may provide subjective improvement in fatigue and energy ...

  14. Mitochondrial genetics

    PubMed Central

    Chinnery, Patrick Francis; Hudson, Gavin

    2013-01-01

    Introduction In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. Sources of data In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. Areas of agreement The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. Areas of controversy The exact mechanisms which govern the inheritance of mtDNA are hotly debated. Growing points Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease. PMID:23704099

  15. Semibiotic Persistence

    NASA Astrophysics Data System (ADS)

    Prothmann, C.; Zauner, K.-P.

    From observation, we find four different strategies to successfully enable structures to persist over extended periods of time. If functionally relevant features are very large compared to the changes that can be effectuated by entropy, the functional structure itself has a high enough probability to erode only slowly over time. If the functionally relevant features are protected from environmental influence by sacrificial layers that absorb the impinging of the environment, deterioration can be avoided or slowed. Loss of functionality can be delayed, even for complex systems, by keeping alternate options for all required components available. Biological systems also apply information processing to actively counter the impact of entropy by mechanisms such as self-repair. The latter strategy increases the overall persistence of living systems and enables them to maintain a highly complex functional organisation during their lifetime and over generations. In contrast to the other strategies, information processing has only low material overhead. While at present engineered technology is far from achieving the self-repair of evolved systems, the semibiotic combination of biological components with conventionally engineered systems may open a path to long-term persistence of functional devices in harsh environments. We review nature's strategies for persistence, and consider early steps taken in the laboratory to import such capabilities into engineered architectures.

  16. Telomerase Reverse Transcriptase and Peroxisome Proliferator-Activated Receptor γ Co-Activator-1α Cooperate to Protect Cells from DNA Damage and Mitochondrial Dysfunction in Vascular Senescence.

    PubMed

    Mendelsohn, Andrew R; Larrick, James W

    2015-10-01

    Reduced telomere length with increasing age in dividing cells has been implicated in contributing to the pathologies of human aging, which include cardiovascular and metabolic disorders, through induction of cellular senescence. Telomere shortening results from the absence of telomerase, an enzyme required to maintain telomere length. Telomerase reverse transcriptase (TERT), the protein subunit of telomerase, is expressed only transiently in a subset of adult somatic cells, which include stem cells and smooth muscle cells. A recent report from Xiong and colleagues demonstrates a pivotal role for the transcription co-factor peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α) in maintaining TERT expression and preventing vascular senescence and atherosclerosis in mice. Ablation of PGC-1α reduced TERT expression and increased DNA damage and reactive oxygen species (ROS), resulting in shortened telomeres and vascular senescence. In the ApoE(-/-) mouse model of atherosclerosis, forced expression of PGC-1α increased expression of TERT, extended telomeres, and reversed genomic DNA damage, vascular senescence, and the development of atherosclerotic plaques. Alpha lipoic acid (ALA) stimulated expression of PGC-1α and TERT and reversed DNA damage, vascular senescence, and atherosclerosis, similarly to ectopic expression of PGC-1α. ALA stimulated cyclic adenosine monophosphate (cAMP) signaling, which in turn activated the cAMP response element-binding protein (CREB), a co-factor for PGC-1α expression. The possibility that ALA might induce TERT to extend telomeres in human cells suggests that ALA may be useful in treating atherosclerosis and other aging-related diseases. However, further investigation is needed to identify whether ALA induces TERT in human cells, which cell types are susceptible, and whether such changes have clinical significance. PMID:26414604

  17. Mitochondrial dysfunction and organophosphorus compounds

    SciTech Connect

    Karami-Mohajeri, Somayyeh; Abdollahi, Mohammad

    2013-07-01

    Organophosphorous (OPs) pesticides are the most widely used pesticides in the agriculture and home. However, many acute or chronic poisoning reports about OPs have been published in the recent years. Mitochondria as a site of cellular oxygen consumption and energy production can be a target for OPs poisoning as a non-cholinergic mechanism of toxicity of OPs. In the present review, we have reviewed and criticized all the evidences about the mitochondrial dysfunctions as a mechanism of toxicity of OPs. For this purpose, all biochemical, molecular, and morphological data were retrieved from various studies. Some toxicities of OPs are arisen from dysfunction of mitochondrial oxidative phosphorylation through alteration of complexes I, II, III, IV and V activities and disruption of mitochondrial membrane. Reductions of adenosine triphosphate (ATP) synthesis or induction of its hydrolysis can impair the cellular energy. The OPs disrupt cellular and mitochondrial antioxidant defense, reactive oxygen species generation, and calcium uptake and promote oxidative and genotoxic damage triggering cell death via cytochrome C released from mitochondria and consequent activation of caspases. The mitochondrial dysfunction induced by OPs can be restored by use of antioxidants such as vitamin E and C, alpha-tocopherol, electron donors, and through increasing the cytosolic ATP level. However, to elucidate many aspect of mitochondrial toxicity of Ops, further studies should be performed. - Highlights: • As a non-cholinergic mechanism of toxicity, mitochondria is a target for OPs. • OPs affect action of complexes I, II, III, IV and V in the mitochondria. • OPs reduce mitochondrial ATP. • OPs promote oxidative and genotoxic damage via release of cytochrome C from mitochondria. • OP-induced mitochondrial dysfunction can be restored by increasing the cytosolic ATP.

  18. Mitochondrial Metabolism in Aging Heart.

    PubMed

    Lesnefsky, Edward J; Chen, Qun; Hoppel, Charles L

    2016-05-13

    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 ≈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

  19. Mitochondrial Stress Signaling Promotes Cellular Adaptations

    PubMed Central

    2014-01-01

    Mitochondrial dysfunction has been implicated in the aetiology of many complex diseases, as well as the ageing process. Much of the research on mitochondrial dysfunction has focused on how mitochondrial damage may potentiate pathological phenotypes. The purpose of this review is to draw attention to the less well-studied mechanisms by which the cell adapts to mitochondrial perturbations. This involves communication of stress to the cell and successful induction of quality control responses, which include mitophagy, unfolded protein response, upregulation of antioxidant and DNA repair enzymes, morphological changes, and if all else fails apoptosis. The mitochondrion is an inherently stressful environment and we speculate that dysregulation of stress signaling or an inability to switch on these adaptations during times of mitochondrial stress may underpin mitochondrial dysfunction and hence amount to pathological states over time. PMID:24587804

  20. Mitochondrial Evolution

    PubMed Central

    Gray, Michael W.

    2012-01-01

    Viewed through the lens of the genome it contains, the mitochondrion is of unquestioned bacterial ancestry, originating from within the bacterial phylum α-Proteobacteria (Alphaproteobacteria). Accordingly, the endosymbiont hypothesis—the idea that the mitochondrion evolved from a bacterial progenitor via symbiosis within an essentially eukaryotic host cell—has assumed the status of a theory. Yet mitochondrial genome evolution has taken radically different pathways in diverse eukaryotic lineages, and the organelle itself is increasingly viewed as a genetic and functional mosaic, with the bulk of the mitochondrial proteome having an evolutionary origin outside Alphaproteobacteria. New data continue to reshape our views regarding mitochondrial evolution, particularly raising the question of whether the mitochondrion originated after the eukaryotic cell arose, as assumed in the classical endosymbiont hypothesis, or whether this organelle had its beginning at the same time as the cell containing it. PMID:22952398

  1. BDE-154 induces mitochondrial permeability transition and impairs mitochondrial bioenergetics.

    PubMed

    Pereira, Lílian Cristina; Miranda, Luiz Felippe Cabral; de Souza, Alecsandra Oliveira; Dorta, Daniel Junqueira

    2014-01-01

    Brominated flame retardants are used in various consumer goods to make these materials difficult to burn. Polybrominated diphenyl ethers (PBDE), which are representative of this class of retardants, consist of two benzene rings linked by an oxygen atom, and contain between 1 and 10 bromine atoms in their chemical structure, with the possibility of up to 209 different congeners. Among these congeners, BDE-154 (hexa-BDE) is persistent in the environment and easy to detect in the biota, but no apparent information regarding the mechanism underlying action and toxicity is available. Mitochondria, as the main energy-producing organelles, play an important role in the maintenance of various cellular functions. Therefore, mitochondria were used in the present study as an experimental model to determine the effects of BDE-154 congener at concentrations ranging from 0.1 μM to 50 μM. Our results demonstrated that BDE-154 interacts with the mitochondrial membrane, preferably by inserting into the hydrophobic core of the mitochondrial membrane, which partially inhibits respiration, dissipates Δψ, and permeabilizes the inner mitochondrial membrane to deplete ATP. These effects are more pronounced at concentrations equal to or higher than 10 μM. Results also showed that BDE-154 did not induce reactive oxygen species (ROS) accumulation within the mitochondria, indicating the absence of oxidative stress. Therefore, BDE-154 impairs mitochondrial bioenergetics and permeabilizes the mitochondrial membrane, potentially leading to cell death but not via mechanisms involving oxidative stress. PMID:24555644

  2. Reduced mitochondrial ROS, enhanced antioxidant defense, and distinct age-related changes in oxidative damage in muscles of long-lived Peromyscus leucopus

    PubMed Central

    Shi, Yun; Pulliam, Daniel A.; Liu, Yuhong; Hamilton, Ryan T.; Jernigan, Amanda L.; Bhattacharya, Arunabh; Sloane, Lauren B.; Qi, Wenbo; Chaudhuri, Asish; Buffenstein, Rochelle; Ungvari, Zoltan; Austad, Steven N.

    2013-01-01

    Comparing biological processes in closely related species with divergent life spans is a powerful approach to study mechanisms of aging. The oxidative stress hypothesis of aging predicts that longer-lived species would have lower reactive oxygen species (ROS) generation and/or an increased antioxidant capacity, resulting in reduced oxidative damage with age than in shorter-lived species. In this study, we measured ROS generation in the young adult animals of the long-lived white-footed mouse, Peromyscus leucopus (maximal life span potential, MLSP = 8 yr) and the common laboratory mouse, Mus musculus (C57BL/6J strain; MLSP = 3.5 yr). Consistent with the hypothesis, our results show that skeletal muscle mitochondria from adult P. leucopus produce less ROS (superoxide and hydrogen peroxide) compared with M. musculus. Additionally, P. leucopus has an increase in the activity of antioxidant enzymes superoxide dismutase 1, catalase, and glutathione peroxidase 1 at young age. P. leucopus compared with M. musculus display low levels of lipid peroxidation (isoprostanes) throughout life; however, P. leucopus although having elevated protein carbonyls at a young age, the accrual of protein oxidation with age is minimal in contrast to the linear increase in M. musculus. Altogether, the results from young animals are in agreement with the predictions of the oxidative stress hypothesis of aging with the exception of protein carbonyls. Nonetheless, the age-dependent increase in protein carbonyls is more pronounced in short-lived M. musculus, which supports enhanced protein homeostasis in long-lived P. leucopus. PMID:23325454

  3. Selenite Stimulates Mitochondrial Biogenesis Signaling and Enhances Mitochondrial Functional Performance in Murine Hippocampal Neuronal Cells

    PubMed Central

    Idris, Haza; Kumari, Santosh; Li, P. Andy

    2012-01-01

    Supplementation of selenium has been shown to protect cells against free radical mediated cell damage. The objectives of this study are to examine whether supplementation of selenium stimulates mitochondrial biogenesis signaling pathways and whether selenium enhances mitochondrial functional performance. Murine hippocampal neuronal HT22 cells were treated with sodium selenite for 24 hours. Mitochondrial biogenesis markers, mitochondrial respiratory rate and activities of mitochondrial electron transport chain complexes were measured and compared to non-treated cells. The results revealed that treatment of selenium to the HT22 cells elevated the levels of nuclear mitochondrial biogenesis regulators PGC-1α and NRF1, as well as mitochondrial proteins cytochrome c and cytochrome c oxidase IV (COX IV). These effects are associated with phosphorylation of Akt and cAMP response element-binding (CREB). Supplementation of selenium significantly increased mitochondrial respiration and improved the activities of mitochondrial respiratory complexes. We conclude that selenium activates mitochondrial biogenesis signaling pathway and improves mitochondrial function. These effects may be associated with modulation of AKT-CREB pathway. PMID:23110128

  4. Mitochondrial Oxidative Stress in Temporal Lobe Epilepsy

    PubMed Central

    Waldbaum, Simon; Patel, Manisha

    2011-01-01

    Mitochondrial oxidative stress and dysfunction are contributing factors to various neurological disorders. Recently, there has been increasing evidence supporting the association between mitochondrial oxidative stress and epilepsy. Although certain inherited epilepsies are associated with mitochondrial dysfunction, little is known about its role in acquired epilepsies such as temporal lobe epilepsy. Mitochondrial oxidative stress and dysfunction are emerging as key factors that not only result from seizures, but may also contribute to epileptogenesis. The occurrence of epilepsy increases with age, and mitochondrial oxidative stress is a leading mechanism of aging and age-related degenerative disease, suggesting a further involvement of mitochondrial dysfunction in seizure generation. Mitochondria have critical cellular functions that effect neuronal excitability including production of adenosine triphosphate (ATP), fatty acid oxidation, control of apoptosis and necrosis, regulation of amino acid cycling, neurotransmitter biosynthesis, and regulation of cytosolic Ca2+ homeostasis. Mitochondria are the primary site of reactive oxygen species (ROS) production making them uniquely vulnerable to oxidative stress and damage which can further affect cellular macromolecule function, the ability of the electron transport chain to produce ATP, antioxidant defenses, mitochondrial DNA stability, and synaptic glutamate homeostasis. Oxidative damage to one or more of these cellular targets may affect neuronal excitability and increase seizure susceptibility. The specific targeting of mitochondrial oxidative stress, dysfunction, and bioenergetics with pharmacological and non-pharmacological treatments may be a novel avenue for attenuating epileptogenesis and seizure initiation. PMID:19850449

  5. Hypobaric Hypoxia Imbalances Mitochondrial Dynamics in Rat Brain Hippocampus

    PubMed Central

    Jain, Khushbu; Prasad, Dipti; Singh, Shashi Bala; Kohli, Ekta

    2015-01-01

    Brain is predominantly susceptible to oxidative stress and mitochondrial dysfunction during hypobaric hypoxia, and therefore undergoes neurodegeneration due to energy crisis. Evidences illustrate a high degree of association for mitochondrial fusion/fission imbalance and mitochondrial dysfunction. Mitochondrial fusion/fission is a recently reported dynamic mechanism which frequently occurs among cellular mitochondrial network. Hence, the study investigated the temporal alteration and involvement of abnormal mitochondrial dynamics (fusion/fission) along with disturbed mitochondrial functionality during chronic exposure to hypobaric hypoxia (HH). The Sprague-Dawley rats were exposed to simulated high altitude equivalent to 25000 ft for 3, 7, 14, 21, and 28 days. Mitochondrial morphology, distribution within neurons, enzyme activity of respiratory complexes, Δψm, ADP: ATP, and expression of fission/fusion key proteins were determined. Results demonstrated HH induced alteration in mitochondrial morphology by damaged, small mitochondria observed in neurons with disturbance of mitochondrial functionality and reduced mitochondrial density in neuronal processes manifested by excessive mitochondrial fragmentation (fission) and decreased mitochondrial fusion as compared to unexposed rat brain hippocampus. The study suggested that imbalance in mitochondrial dynamics is one of the noteworthy mechanisms occurring in hippocampal neurons during HH insult. PMID:26236504

  6. Stress-induced OMA1 activation and autocatalytic turnover regulate OPA1-dependent mitochondrial dynamics

    PubMed Central

    Baker, Michael J; Lampe, Philipp A; Stojanovski, Diana; Korwitz, Anne; Anand, Ruchika; Tatsuta, Takashi; Langer, Thomas

    2014-01-01

    The dynamic network of mitochondria fragments under stress allowing the segregation of damaged mitochondria and, in case of persistent damage, their selective removal by mitophagy. Mitochondrial fragmentation upon depolarisation of mitochondria is brought about by the degradation of central components of the mitochondrial fusion machinery. The OMA1 peptidase mediates the degradation of long isoforms of the dynamin-like GTPase OPA1 in the inner membrane. Here, we demonstrate that OMA1-mediated degradation of OPA1 is a general cellular stress response. OMA1 is constitutively active but displays strongly enhanced activity in response to various stress insults. We identify an amino terminal stress-sensor domain of OMA1, which is only present in homologues of higher eukaryotes and which modulates OMA1 proteolysis and activation. OMA1 activation is associated with its autocatalyic degradation, which initiates from both termini of OMA1 and results in complete OMA1 turnover. Autocatalytic proteolysis of OMA1 ensures the reversibility of the response and allows OPA1-mediated mitochondrial fusion to resume upon alleviation of stress. This differentiated stress response maintains the functional integrity of mitochondria and contributes to cell survival. PMID:24550258

  7. Aberrant Nucleo-cytoplasmic Cross-Talk Results in Donor Cell mtDNA Persistence in Cloned Embryos

    PubMed Central

    Lloyd, Rhiannon E.; Lee, Joon-Hee; Alberio, Ramiro; Bowles, Emma J.; Ramalho-Santos, João; Campbell, Keith H. S.; St. John, Justin C.

    2006-01-01

    Mitochondrial DNA is an extranuclear genome normally maternally inherited through the oocyte. However, the use of nuclear transfer can result in both donor cell and recipient oocyte mitochondrial DNA persisting through to blastocyst and being transmitted to the offspring. The degree of donor mitochondrial DNA transmission appears to be random and currently no evidence exists to explain this phenomenon. To determine whether this is a dilution factor or directly related to the transcriptional status of the donor cell in respect of mitochondrial DNA transcription factors, we have generated sheep nuclear transfer embryos using donor cells: (1) possessing their full mitochondrial DNA complement, (2) those partially depleted, and (3) those depleted but containing residual levels. For each donor type, donor mitochondrial DNA persisted in some blastocysts. It is evident from the donor cells used that nuclear-encoded mitochondrial DNA transcription and replication factors persist even after mitochondrial DNA depletion, as do transcripts for some of the mitochondrial-encoded genes. These cells are therefore still programmed to drive mitochondrial DNA replication and transcription. In nuclear transfer-derived embryos, we have observed the persistence of these nuclear-encoded mitochondrial DNA transcription and replication factors but not in those embryos generated through in vitro fertilization. Consequently, nucleo-mitochondrial interaction following nuclear transfer is out of sequence as the onset of mitochondrial replication is a postimplantation event. PMID:16452133

  8. Diet impact on mitochondrial bioenergetics and dynamics

    PubMed Central

    Putti, Rosalba; Sica, Raffaella; Migliaccio, Vincenzo; Lionetti, Lillà

    2015-01-01

    Diet induced obesity is associated with impaired mitochondrial function and dynamic behavior. Mitochondria are highly dynamic organelles and the balance in fusion/fission is strictly associated with their bioenergetics. Fusion processes are associated with the optimization of mitochondrial function, whereas fission processes are associated with the removal of damaged mitochondria. In diet-induced obesity, impaired mitochondrial function and increased fission processes were found in liver and skeletal muscle. Diverse dietary fat sources differently affect mitochondrial dynamics and bioenergetics. In contrast to saturated fatty acids, omega 3 polyunsaturated fatty acids induce fusion processes and improve mitochondrial function. Moreover, the pro-longevity effect of caloric restriction has been correlated with changes in mitochondrial dynamics leading to decreased cell oxidative injury. Noteworthy, emerging findings revealed an important role for mitochondrial dynamics within neuronal populations involved in central regulation of body energy balance. In conclusion, mitochondrial dynamic processes with their strict interconnection with mitochondrial bioenergetics are involved in energy balance and diet impact on metabolic tissues. PMID:25904870

  9. 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.

  10. Parkin suppresses Drp1-independent mitochondrial division.

    PubMed

    Roy, Madhuparna; Itoh, Kie; Iijima, Miho; Sesaki, Hiromi

    2016-07-01

    The cycle of mitochondrial division and fusion disconnect and reconnect individual mitochondria in cells to remodel this energy-producing organelle. Although dynamin-related protein 1 (Drp1) plays a major role in mitochondrial division in cells, a reduced level of mitochondrial division still persists even in the absence of Drp1. It is unknown how much Drp1-mediated mitochondrial division accounts for the connectivity of mitochondria. The role of a Parkinson's disease-associated protein-parkin, which biochemically and genetically interacts with Drp1-in mitochondrial connectivity also remains poorly understood. Here, we quantified the number and connectivity of mitochondria using mitochondria-targeted photoactivatable GFP in cells. We show that the loss of Drp1 increases the connectivity of mitochondria by 15-fold in mouse embryonic fibroblasts (MEFs). While a single loss of parkin does not affect the connectivity of mitochondria, the connectivity of mitochondria significantly decreased compared with a single loss of Drp1 when parkin was lost in the absence of Drp1. Furthermore, the loss of parkin decreased the frequency of depolarization of the mitochondrial inner membrane that is caused by increased mitochondrial connectivity in Drp1-knockout MEFs. Therefore, our data suggest that parkin negatively regulates Drp1-indendent mitochondrial division. PMID:27181353

  11. Barriers to male transmission of mitochondrial DNA in sperm development.

    PubMed

    DeLuca, Steven Z; O'Farrell, Patrick H

    2012-03-13

    Across the eukaryotic phylogeny, offspring usually inherit their mitochondrial genome from only one of two parents: in animals, the female. Although mechanisms that eliminate paternally derived mitochondria from the zygote have been sought, the developmental stage at which paternal transmission of mitochondrial DNA is restricted is unknown in most animals. Here, we show that the mitochondria of mature Drosophila sperm lack DNA, and we uncover two processes that eliminate mitochondrial DNA during spermatogenesis. Visualization of mitochondrial DNA nucleoids revealed their abrupt disappearance from developing spermatids in a process requiring the mitochondrial nuclease, Endonuclease G. In Endonuclease G mutants, persisting nucleoids are swept out of spermatids by a cellular remodeling process that trims and shapes spermatid tails. Our results show that mitochondrial DNA is eliminated during spermatogenesis, thereby removing the capacity of sperm to transmit the mitochondrial genome to the next generation. PMID:22421049

  12. Mitochondrial Protein Quality Control: The Mechanisms Guarding Mitochondrial Health

    PubMed Central

    Bohovych, Iryna; Chan, Sherine S.L.

    2015-01-01

    Abstract Significance: Mitochondria are complex dynamic organelles pivotal for cellular physiology and human health. Failure to maintain mitochondrial health leads to numerous maladies that include late-onset neurodegenerative diseases and cardiovascular disorders. Furthermore, a decline in mitochondrial health is prevalent with aging. A set of evolutionary conserved mechanisms known as mitochondrial quality control (MQC) is involved in recognition and correction of the mitochondrial proteome. Recent Advances: Here, we review current knowledge and latest developments in MQC. We particularly focus on the proteolytic aspect of MQC and its impact on health and aging. Critical Issues: While our knowledge about MQC is steadily growing, critical gaps remain in the mechanistic understanding of how MQC modules sense damage and preserve mitochondrial welfare, particularly in higher organisms. Future Directions: Delineating how coordinated action of the MQC modules orchestrates physiological responses on both organellar and cellular levels will further elucidate the current picture of MQC's role and function in health, cellular stress, and degenerative diseases. Antioxid. Redox Signal. 22, 977–994. PMID:25546710

  13. Loss of Mitochondrial Function Impairs Lysosomes.

    PubMed

    Demers-Lamarche, Julie; Guillebaud, Gérald; Tlili, Mouna; Todkar, Kiran; Bélanger, Noémie; Grondin, Martine; Nguyen, Angela P; Michel, Jennifer; Germain, Marc

    2016-05-01

    Alterations in mitochondrial function, as observed in neurodegenerative diseases, lead to disrupted energy metabolism and production of damaging reactive oxygen species. Here, we demonstrate that mitochondrial dysfunction also disrupts the structure and function of lysosomes, the main degradation and recycling organelle. Specifically, inhibition of mitochondrial function, following deletion of the mitochondrial protein AIF, OPA1, or PINK1, as well as chemical inhibition of the electron transport chain, impaired lysosomal activity and caused the appearance of large lysosomal vacuoles. Importantly, our results show that lysosomal impairment is dependent on reactive oxygen species. Given that alterations in both mitochondrial function and lysosomal activity are key features of neurodegenerative diseases, this work provides important insights into the etiology of neurodegenerative diseases. PMID:26987902

  14. Altered Mitochondrial Dynamics and TBI Pathophysiology.

    PubMed

    Fischer, Tara D; Hylin, Michael J; Zhao, Jing; Moore, Anthony N; Waxham, M Neal; Dash, Pramod K

    2016-01-01

    Mitochondrial function is intimately linked to cellular survival, growth, and death. Mitochondria not only generate ATP from oxidative phosphorylation, but also mediate intracellular calcium buffering, generation of reactive oxygen species (ROS), and apoptosis. Electron leakage from the electron transport chain, especially from damaged or depolarized mitochondria, can generate excess free radicals that damage cellular proteins, DNA, and lipids. Furthermore, mitochondrial damage releases pro-apoptotic factors to initiate cell death. Previous studies have reported that traumatic brain injury (TBI) reduces mitochondrial respiration, enhances production of ROS, and triggers apoptotic cell death, suggesting a prominent role of mitochondria in TBI pathophysiology. Mitochondria maintain cellular energy homeostasis and health via balanced processes of fusion and fission, continuously dividing and fusing to form an interconnected network throughout the cell. An imbalance of these processes, particularly an excess of fission, can be detrimental to mitochondrial function, causing decreased respiration, ROS production, and apoptosis. Mitochondrial fission is regulated by the cytosolic GTPase, dynamin-related protein 1 (Drp1), which translocates to the mitochondrial outer membrane (MOM) to initiate fission. Aberrant Drp1 activity has been linked to excessive mitochondrial fission and neurodegeneration. Measurement of Drp1 levels in purified hippocampal mitochondria showed an increase in TBI animals as compared to sham controls. Analysis of cryo-electron micrographs of these mitochondria also showed that TBI caused an initial increase in the length of hippocampal mitochondria at 24 h post-injury, followed by a significant decrease in length at 72 h. Post-TBI administration of Mitochondrial division inhibitor-1 (Mdivi-1), a pharmacological inhibitor of Drp1, prevented this decrease in mitochondria length. Mdivi-1 treatment also reduced the loss of newborn neurons in the

  15. Altered Mitochondrial Dynamics and TBI Pathophysiology

    PubMed Central

    Fischer, Tara D.; Hylin, Michael J.; Zhao, Jing; Moore, Anthony N.; Waxham, M. Neal; Dash, Pramod K.

    2016-01-01

    Mitochondrial function is intimately linked to cellular survival, growth, and death. Mitochondria not only generate ATP from oxidative phosphorylation, but also mediate intracellular calcium buffering, generation of reactive oxygen species (ROS), and apoptosis. Electron leakage from the electron transport chain, especially from damaged or depolarized mitochondria, can generate excess free radicals that damage cellular proteins, DNA, and lipids. Furthermore, mitochondrial damage releases pro-apoptotic factors to initiate cell death. Previous studies have reported that traumatic brain injury (TBI) reduces mitochondrial respiration, enhances production of ROS, and triggers apoptotic cell death, suggesting a prominent role of mitochondria in TBI pathophysiology. Mitochondria maintain cellular energy homeostasis and health via balanced processes of fusion and fission, continuously dividing and fusing to form an interconnected network throughout the cell. An imbalance of these processes, particularly an excess of fission, can be detrimental to mitochondrial function, causing decreased respiration, ROS production, and apoptosis. Mitochondrial fission is regulated by the cytosolic GTPase, dynamin-related protein 1 (Drp1), which translocates to the mitochondrial outer membrane (MOM) to initiate fission. Aberrant Drp1 activity has been linked to excessive mitochondrial fission and neurodegeneration. Measurement of Drp1 levels in purified hippocampal mitochondria showed an increase in TBI animals as compared to sham controls. Analysis of cryo-electron micrographs of these mitochondria also showed that TBI caused an initial increase in the length of hippocampal mitochondria at 24 h post-injury, followed by a significant decrease in length at 72 h. Post-TBI administration of Mitochondrial division inhibitor-1 (Mdivi-1), a pharmacological inhibitor of Drp1, prevented this decrease in mitochondria length. Mdivi-1 treatment also reduced the loss of newborn neurons in the

  16. United Mitochondrial Disease Foundation

    MedlinePlus

    ... Caregivers! Want to help? Enroll now in the Mitochondrial Disease Community Registry to advance the development of treatments and cures. HOME What is Mitochondrial Disease Types of Mitochondrial Disease Possible Symptoms Getting a ...

  17. What Is Mitochondrial DNA?

    MedlinePlus

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  18. Mitochondrial dysfunction in ataxia-telangiectasia.

    PubMed

    Valentin-Vega, Yasmine A; Maclean, Kirsteen H; Tait-Mulder, Jacqueline; Milasta, Sandra; Steeves, Meredith; Dorsey, Frank C; Cleveland, John L; Green, Douglas R; Kastan, Michael B

    2012-02-01

    Ataxia-telangiectasia mutated (ATM) plays a central role in DNA damage responses, and its loss leads to development of T-cell malignancies. Here, we show that ATM loss also leads to intrinsic mitochondrial abnormalities in thymocytes, including elevated reactive oxygen species, increased aberrant mitochondria, high cellular respiratory capacity, and decreased mitophagy. A fraction of ATM protein is localized in mitochondria, and it is rapidly activated by mitochondrial dysfunction. Unexpectedly, allelic loss of the autophagy regulator Beclin-1 significantly delayed tumor development in ATM-null mice. This effect was not associated with rescue of DNA damage signaling but rather with a significant reversal of the mitochondrial abnormalities. These data support a model in which ATM plays direct roles in modulating mitochondrial homeostasis and suggest that mitochondrial dysfunction and associated increases in mitochondrial reactive oxygen species contribute to the cancer-prone phenotype observed in organisms lacking ATM. Thus, ataxia-telangiectasia should be considered, at least in part, as a mitochondrial disease. PMID:22144182

  19. Mitochondrial tRNA cleavage by tRNA-targeting ribonuclease causes mitochondrial dysfunction observed in mitochondrial disease

    SciTech Connect

    Ogawa, Tetsuhiro Shimizu, Ayano; Takahashi, Kazutoshi; Hidaka, Makoto; Masaki, Haruhiko

    2014-08-15

    Highlights: • MTS-tagged ribonuclease was translocated successfully to the mitochondrial matrix. • MTS-tagged ribonuclease cleaved mt tRNA and reduced COX activity. • Easy and reproducible method of inducing mt tRNA dysfunction. - Abstract: Mitochondrial DNA (mtDNA) is a genome possessed by mitochondria. Since reactive oxygen species (ROS) are generated during aerobic respiration in mitochondria, mtDNA is commonly exposed to the risk of DNA damage. Mitochondrial disease is caused by mitochondrial dysfunction, and mutations or deletions on mitochondrial tRNA (mt tRNA) genes are often observed in mtDNA of patients with the disease. Hence, the correlation between mt tRNA activity and mitochondrial dysfunction has been assessed. Then, cybrid cells, which are constructed by the fusion of an enucleated cell harboring altered mtDNA with a ρ{sup 0} cell, have long been used for the analysis due to difficulty in mtDNA manipulation. Here, we propose a new method that involves mt tRNA cleavage by a bacterial tRNA-specific ribonuclease. The ribonuclease tagged with a mitochondrial-targeting sequence (MTS) was successfully translocated to the mitochondrial matrix. Additionally, mt tRNA cleavage, which resulted in the decrease of cytochrome c oxidase (COX) activity, was observed.

  20. Mitochondrial transplantation for therapeutic use.

    PubMed

    McCully, James D; Levitsky, Sidney; Del Nido, Pedro J; Cowan, Douglas B

    2016-03-01

    Mitochondria play a key role in the homeostasis of the vast majority of the body's cells. In the myocardium where mitochondria constitute 30 % of the total myocardial cell volume, temporary attenuation or obstruction of blood flow and as a result oxygen delivery to myocardial cells (ischemia) severely alters mitochondrial structure and function. These alterations in mitochondrial structure and function occur during ischemia and continue after blood flow and oxygen delivery to the myocardium is restored, and significantly decrease myocardial contractile function and myocardial cell survival. We hypothesized that the augmentation or replacement of mitochondria damaged by ischemia would provide a mechanism to enhance cellular function and cellular rescue following the restoration of blood flow. To test this hypothesis we have used a model of myocardial ischemia and reperfusion. Our studies demonstrate that the transplantation of autologous mitochondria, isolated from the patient's own body, and then directly injected into the myocardial during early reperfusion augment the function of native mitochondria damaged during ischemia and enhances myocardial post-ischemic functional recovery and cellular viability. The transplanted mitochondria act both extracellularly and intracellularly. Extracellularly, the transplanted mitochondria enhance high energy synthesis and cellular adenosine triphosphate stores and alter the myocardial proteome. Once internalized the transplanted mitochondria rescue cellular function and replace damaged mitochondrial DNA. There is no immune or auto-immune reaction and there is no pro-arrhythmia as a result of the transplanted mitochondria. Our studies and those of others demonstrate that mitochondrial transplantation can be effective in a number of cell types and diseases. These include cardiac and skeletal muscle, pulmonary and hepatic tissue and cells and in neuronal tissue. In this review we discuss the mechanisms leading to mitochondrial

  1. Mitochondrial dynamism and cardiac fate--a personal perspective.

    PubMed

    Dorn, Gerald W

    2013-01-01

    Defects in mitochondrial biogenesis are well known to contribute to cardiac dysfunction. By contrast, mechanistic details of essential homeostatic mechanisms that maintain mitochondrial health in the heart are only recently being uncovered, and the pathological potential of these processes is largely hypothetical. I will review the role of mitochondrial dynamics, focusing on cyclic organelle fission and fusion, in normal and diseased hearts. Special attention is given to recent insights into the non-canonical functioning of the mitofusin 2 (Mfn2) outer mitochondrial membrane fusion protein as a regulator of sarcoplasmic-reticular calcium crosstalk and a critical determinant of mitophagic culling of damaged mitochondria. Because mitochondrial fusion in normal adult cardiomyocytes occurs so slowly and infrequently, I postulate that the major function of Mfn2 in the heart may not be to redundantly promote mitochondrial fusion with Mfn1, but to centrally orchestrate mitochondrial quality control.   PMID:23615052

  2. Mitochondrial Dynamics and Mitochondrial Dysfunction in Diabetes.

    PubMed

    Wada, Jun; Nakatsuka, Atsuko

    2016-06-01

    The mitochondria are involved in active and dynamic processes, such as mitochondrial biogenesis, fission, fusion and mitophagy to maintain mitochondrial and cellular functions. In obesity and type 2 diabetes, impaired oxidation, reduced mitochondrial contents, lowered rates of oxidative phosphorylation and excessive reactive oxygen species (ROS) production have been reported. Mitochondrial biogenesis is regulated by various transcription factors such as peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), peroxisome proliferator-activated receptors (PPARs), estrogen-related receptors (ERRs), and nuclear respiratory factors (NRFs). Mitochondrial fusion is promoted by mitofusin 1 (MFN1), mitofusin 2 (MFN2) and optic atrophy 1 (OPA1), while fission is governed by the recruitment of dynamin-related protein 1 (DRP1) by adaptor proteins such as mitochondrial fission factor (MFF), mitochondrial dynamics proteins of 49 and 51 kDa (MiD49 and MiD51), and fission 1 (FIS1). Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) and PARKIN promote DRP1-dependent mitochondrial fission, and the outer mitochondrial adaptor MiD51 is required in DRP1 recruitment and PARKIN-dependent mitophagy. This review describes the molecular mechanism of mitochondrial dynamics, its abnormality in diabetes and obesity, and pharmaceuticals targeting mitochondrial biogenesis, fission, fusion and mitophagy. PMID:27339203

  3. Mitochondrial Dysfunction in Amyotrophic Lateral Sclerosis

    PubMed Central

    Shi, Ping; Gal, Jozsef; Kwinter, David M.; Liu, Xiaoyan; Zhu, Haining

    2009-01-01

    The etiology of motor neuron degeneration in amyotrophic lateral sclerosis (ALS) remains to be better understood. Based on the studies from ALS patients and transgenic animal models, it is believed that ALS is likely to be a multifactorial and multisystem disease. Many mechanisms have been postulated to be involved in the pathology of ALS, such as oxidative stress, glutamate excitotoxicity, mitochondrial damage, defective axonal transport, glia cell pathology and aberrant RNA metabolism. Mitochondria, which play crucial roles in excitotoxicity, apoptosis and cell survival, have shown to be an early target in ALS pathogenesis and contribute to the disease progression. Morphological and functional defects in mitochondria were found in both human patients and ALS mice overexpressing mutant SOD1. Mutant SOD1 was found to be preferentially associated with mitochondria and subsequently impair mitochondrial function. Recent studies suggest that axonal transport of mitochondria along microtubules and mitochondrial dynamics may also be disrupted in ALS. These results also illustrate the critical importance of maintaining proper mitochondrial function in axons and neuromuscular junctions, supporting the emerging “dying-back” axonopathy model of ALS. In this review, we will discuss how mitochondrial dysfunction has been linked to the ALS variants of SOD1 and the mechanisms by which mitochondrial damage contributes to the disease etiology. PMID:19715760

  4. Exacerbation of acute kidney injury by bone marrow stromal cells from rats with persistent renin-angiotensin system activation.

    PubMed

    Kankuri, Esko; Mervaala, Elina E; Storvik, Markus; Ahola, Aija M J; Levijoki, Jouko; Müller, Dominik N; Finckenberg, Piet; Mervaala, Eero M

    2015-06-01

    Hypertension and persistent activation of the renin-angiotensin system (RAS) are predisposing factors for the development of acute kidney injury (AKI). Although bone-marrow-derived stromal cells (BMSCs) have shown therapeutic promise in treatment of AKI, the impact of pathological RAS on BMSC functionality has remained unresolved. RAS and its local components in the bone marrow are involved in several key steps of cell maturation processes. This may also render the BMSC population vulnerable to alterations even in the early phases of RAS pathology. We isolated transgenic BMSCs (TG-BMSCs) from young end-organ-disease-free rats with increased RAS activation [human angiotensinogen/renin double transgenic rats (dTGRs)] that eventually develop hypertension and die of end-organ damage and kidney failure at 8 weeks of age. Control cells (SD-BMSCs) were isolated from wild-type Sprague-Dawley rats. Cell phenotype, mitochondrial reactive oxygen species (ROS) production and respiration were assessed, and gene expression profiling was carried out using microarrays. Cells' therapeutic efficacy was evaluated in a rat model of acute ischaemia/reperfusion-induced AKI. Serum urea and creatinine were measured at 24 h and 48 h. Acute tubular damage was scored and immunohistochemistry was used for evaluation for markers of inflammation [monocyte chemoattractant protein (MCP-1), ED-1], and kidney injury [kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL)]. TG-BMSCs showed distinct mitochondrial morphology, decreased cell respiration and increased production of ROS. Gene expression profiling revealed a pronounced pro-inflammatory phenotype. In contrast with the therapeutic effect of SD-BMSCs, administration of TG-BMSCs in the AKI model resulted in exacerbation of kidney injury and high mortality. Our results demonstrate that early persistent RAS activation can dramatically compromise therapeutic potential of BMSCs by causing a shift into a pro

  5. Cancer as a mitochondrial metabolic disease

    PubMed Central

    Seyfried, Thomas N.

    2015-01-01

    Cancer is widely considered a genetic disease involving nuclear mutations in oncogenes and tumor suppressor genes. This view persists despite the numerous inconsistencies associated with the somatic mutation theory. In contrast to the somatic mutation theory, emerging evidence suggests that cancer is a mitochondrial metabolic disease, according to the original theory of Otto Warburg. The findings are reviewed from nuclear cytoplasm transfer experiments that relate to the origin of cancer. The evidence from these experiments is difficult to reconcile with the somatic mutation theory, but is consistent with the notion that cancer is primarily a mitochondrial metabolic disease. PMID:26217661

  6. Mitochondrial Drugs for Alzheimer Disease

    PubMed Central

    Bonda, David J.; Wang, Xinglong; Gustaw-Rothenberg, Katarzyna A.; Perry, George; Smith, Mark A.; Zhu, Xiongwei

    2009-01-01

    Therapeutic strategies for Alzheimer disease (AD) have yet to offer a disease-modifying effect to stop the debilitating progression of neurodegeneration and cognitive decline. Rather, treatments thus far are limited to agents that slow disease progression without halting it, and although much work towards a cure is underway, a greater understanding of disease etiology is certainly necessary for any such achievement. Mitochondria, as the centers of cellular metabolic activity and the primary generators of reactive oxidative species in the cell, received particular attention especially given that mitochondrial defects are known to contribute to cellular damage. Furthermore, as oxidative stress has come to the forefront of AD as a causal theory, and as mitochondrial damage is known to precede much of the hallmark pathologies of AD, it seems increasingly apparent that this metabolic organelle is ultimately responsible for much, if not all of disease pathogenesis. In this review, we review the role of neuronal mitochondria in the pathogenesis of AD and critically assess treatment strategies that utilize this upstream access point as a method for disease prevention. We suspect that, with a revived focus on mitochondrial repair and protection, an effective and realistic therapeutic agent can be successfully developed. PMID:20657666

  7. Mitochondrial Drugs for Alzheimer Disease.

    PubMed

    Bonda, David J; Wang, Xinglong; Gustaw-Rothenberg, Katarzyna A; Perry, George; Smith, Mark A; Zhu, Xiongwei

    2009-12-23

    Therapeutic strategies for Alzheimer disease (AD) have yet to offer a disease-modifying effect to stop the debilitating progression of neurodegeneration and cognitive decline. Rather, treatments thus far are limited to agents that slow disease progression without halting it, and although much work towards a cure is underway, a greater understanding of disease etiology is certainly necessary for any such achievement. Mitochondria, as the centers of cellular metabolic activity and the primary generators of reactive oxidative species in the cell, received particular attention especially given that mitochondrial defects are known to contribute to cellular damage. Furthermore, as oxidative stress has come to the forefront of AD as a causal theory, and as mitochondrial damage is known to precede much of the hallmark pathologies of AD, it seems increasingly apparent that this metabolic organelle is ultimately responsible for much, if not all of disease pathogenesis. In this review, we review the role of neuronal mitochondria in the pathogenesis of AD and critically assess treatment strategies that utilize this upstream access point as a method for disease prevention. We suspect that, with a revived focus on mitochondrial repair and protection, an effective and realistic therapeutic agent can be successfully developed. PMID:20657666

  8. In-Utero Low-Dose Irradiation Leads to Persistent Alterations in the Mouse Heart Proteome

    PubMed Central

    Bakshi, Mayur V.; Azimzadeh, Omid; Merl-Pham, Juliane; Verreet, Tine; Hauck, Stefanie M.; Benotmane, Mohammed A.; Atkinson, Michael J.; Tapio, Soile

    2016-01-01

    Prenatal exposure to stress such as increased level of reactive oxygen species or antiviral therapy are known factors leading to adult heart defects. The risks following a radiation exposure during fetal period are unknown, as are the mechanisms of any potential cardiac damage. The aim of this study was to gather evidence for possible damage by investigating long-term changes in the mouse heart proteome after prenatal exposure to low and moderate radiation doses. Pregnant C57Bl/6J mice received on embryonic day 11 (E11) a single total body dose of ionizing radiation that ranged from 0.02 Gy to 1.0 Gy. The offspring were sacrificed at the age of 6 months or 2 years. Quantitative proteomic analysis of heart tissue was performed using Isotope Coded Protein Label technology and tandem mass spectrometry. The proteomics data were analyzed by bioinformatics and key changes were validated by immunoblotting. Persistent changes were observed in the expression of proteins representing mitochondrial respiratory complexes, redox and heat shock response, and the cytoskeleton, even at the low dose of 0.1 Gy. The level of total and active form of the kinase MAP4K4 that is essential for the embryonic development of mouse heart was persistently decreased at the radiation dose of 1.0 Gy. This study provides the first insight into the molecular mechanisms of cardiac impairment induced by ionizing radiation exposure during the prenatal period. PMID:27276052

  9. Mitochondrial dynamics, mitophagy and cardiovascular disease.

    PubMed

    Vásquez-Trincado, César; García-Carvajal, Ivonne; Pennanen, Christian; Parra, Valentina; Hill, Joseph A; Rothermel, Beverly A; Lavandero, Sergio

    2016-02-01

    Cardiac hypertrophy is often initiated as an adaptive response to haemodynamic stress or myocardial injury, and allows the heart to meet an increased demand for oxygen. Although initially beneficial, hypertrophy can ultimately contribute to the progression of cardiac disease, leading to an increase in interstitial fibrosis and a decrease in ventricular function. Metabolic changes have emerged as key mechanisms involved in the development and progression of pathological remodelling. As the myocardium is a highly oxidative tissue, mitochondria play a central role in maintaining optimal performance of the heart. 'Mitochondrial dynamics', the processes of mitochondrial fusion, fission, biogenesis and mitophagy that determine mitochondrial morphology, quality and abundance have recently been implicated in cardiovascular disease. Studies link mitochondrial dynamics to the balance between energy demand and nutrient supply, suggesting that changes in mitochondrial morphology may act as a mechanism for bioenergetic adaptation during cardiac pathological remodelling. Another critical function of mitochondrial dynamics is the removal of damaged and dysfunctional mitochondria through mitophagy, which is dependent on the fission/fusion cycle. In this article, we discuss the latest findings regarding the impact of mitochondrial dynamics and mitophagy on the development and progression of cardiovascular pathologies, including diabetic cardiomyopathy, atherosclerosis, damage from ischaemia-reperfusion, cardiac hypertrophy and decompensated heart failure. We will address the ability of mitochondrial fusion and fission to impact all cell types within the myocardium, including cardiac myocytes, cardiac fibroblasts and vascular smooth muscle cells. Finally, we will discuss how these findings can be applied to improve the treatment and prevention of cardiovascular diseases. PMID:26537557

  10. Cold Storage Exacerbates Renal and Mitochondrial Dysfunction Following Transplantation

    PubMed Central

    Shrum, S; MacMillan-Crow, LA; Parajuli, N

    2016-01-01

    Long-term renal function is compromised in patients receiving deceased donor kidneys which require cold storage exposure prior to transplantation. It is well established that extended cold storage induces renal damage and several labs, including our own, have demonstrated renal mitochondrial damage after cold storage alone. However, to our knowledge, few studies have assessed renal and mitochondrial function after transplantation of rat kidneys exposed to short-term (4 hr) cold storage compared to transplant without cold storage (autotransplantation). Our data reveal that cold storage plus transplantation exacerbated renal and mitochondrial dysfunction when compared to autotransplantation alone. PMID:27066594

  11. Demyelination increases axonal stationary mitochondrial size and the speed of axonal mitochondrial transport

    PubMed Central

    Kiryu-Seo, Sumiko; Ohno, Nobuhiko; Kidd, Grahame J.; Komuro, Hitoshi; Trapp, Bruce D.

    2010-01-01

    Axonal degeneration contributes to permanent neurological disability in inherited and acquired diseases of myelin. Mitochondrial dysfunction has been proposed as a major contributor to this axonal degeneration. It remains to be determined, however, if myelination, demyelination or remyelination alter the size and distribution of axonal mitochondrial stationary sites or the rates of axonal mitochondrial transport. Using live myelinated rat dorsal root ganglion (DRG) cultures, we investigated whether myelination and lysolecithin-induced demyelination affect axonal mitochondria. Myelination increased the size of axonal stationary mitochondrial sites by 2.3 fold. Following demyelination, the size of axonal stationary mitochondrial sites was increased by an additional 2.2 fold and the transport velocity of motile mitochondria was increased by 47%. These measures returned to the levels of myelinated axons following remyelination. Demyelination induced activating transcription factor (ATF) 3 in DRG neurons. Knockdown of neuronal ATF3 by shRNA abolished the demyelination-induced increase in axonal mitochondrial transport and increased nitrotyrosine immunoreactivity in axonal mitochondria, suggesting that neuronal ATF3 expression and increased mitochondrial transport protect demyelinated axons from oxidative damage. In response to insufficient ATP production, demyelinated axons increase the size of stationary mitochondrial sites and thereby balance ATP production with the increased energy needs of nerve conduction. PMID:20463228

  12. Mitochondrial Rejuvenation After Induced Pluripotency

    PubMed Central

    Tjong, Jonathan; Alcasid, Nathan; Perkins, Guy A.; Goissis, Marcelo D.; Ellisman, Mark H.; Perez, Gloria I.; Cibelli, Jose B.

    2010-01-01

    Background As stem cells of the early embryo mature and differentiate into all tissues, the mitochondrial complement undergoes dramatic functional improvement. Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands. It has recently been reported that when the stem cell type known as induced pluripotent stem cells (IPSCs) are re-differentiated for several weeks in vitro, the mitochondrial complement progressively re-acquires properties approximating input fibroblasts, suggesting that despite the observation that IPSC conversion “resets” some parameters of cellular aging such as telomere length, it may have little impact on other age-affected cellular systems such as mitochondria in IPSC-derived cells. Methodology/Principal Findings We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts. This observation likely stems from two aspects of our experimental design: 1) that the input cell lines used were of advanced cellular age and contained an inefficient mitochondrial complement, and 2) the re-derived fibroblasts were produced using an extensive differentiation regimen that may more closely mimic the degree of growth and maturation found in a developing mammal. Conclusions/Significance These results — coupled with earlier data from our laboratory — suggest that IPSC conversion not only resets the “biological clock”, but can also rejuvenate the energetic capacity of derived cells. PMID:21124794

  13. Mitochondrial disease and epilepsy.

    PubMed

    Rahman, Shamima

    2012-05-01

    Mitochondrial respiratory chain disorders are relatively common inborn errors of energy metabolism, with a combined prevalence of one in 5000. These disorders typically affect tissues with high energy requirements, and cerebral involvement occurs frequently in childhood, often manifesting in seizures. Mitochondrial diseases are genetically heterogeneous; to date, mutations have been reported in all 37 mitochondrially encoded genes and more than 80 nuclear genes. The major genetic causes of mitochondrial epilepsy are mitochondrial DNA mutations (including those typically associated with the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS] and myoclonic epilepsy with ragged red fibres [MERRF] syndromes); mutations in POLG (classically associated with Alpers syndrome but also presenting as the mitochondrial recessive ataxia syndrome [MIRAS], spinocerebellar ataxia with epilepsy [SCAE], and myoclonus, epilepsy, myopathy, sensory ataxia [MEMSA] syndromes in older individuals) and other disorders of mitochondrial DNA maintenance; complex I deficiency; disorders of coenzyme Q(10) biosynthesis; and disorders of mitochondrial translation such as RARS2 mutations. It is not clear why some genetic defects, but not others, are particularly associated with seizures. Epilepsy may be the presenting feature of mitochondrial disease but is often part of a multisystem clinical presentation. Mitochondrial epilepsy may be very difficult to manage, and is often a poor prognostic feature. At present there are no curative treatments for mitochondrial disease. Individuals with mitochondrial epilepsy are frequently prescribed multiple anticonvulsants, and the role of vitamins and other nutritional supplements and the ketogenic diet remain unproven. PMID:22283595

  14. Pivotal role of AKAP121 in mitochondrial physiology.

    PubMed

    Czachor, Alexander; Failla, Athena; Lockey, Richard; Kolliputi, Narasaiah

    2016-04-15

    In this Perspective, we discuss some recent developments in the study of the mitochondrial scaffolding protein AKAP121 (also known as AKAP1, or AKAP149 as the human homolog), with an emphasis on its role in mitochondrial physiology. AKAP121 has been identified to function as a key regulatory molecule in several mitochondrial events including oxidative phosphorylation, the control of membrane potential, fission-induced apoptosis, maintenance of mitochondrial Ca(2+)homeostasis, and the phosphorylation of various mitochondrial respiratory chain substrate molecules. Furthermore, we discuss the role of hypoxia in prompting cellular stress and damage, which has been demonstrated to mediate the proteosomal degradation of AKAP121, leading to an increase in reactive oxgyen species production, mitochondrial dysfunction, and ultimately cell death. PMID:26825124

  15. Nuclear DNA damage signalling to mitochondria in ageing.

    PubMed

    Fang, Evandro Fei; Scheibye-Knudsen, Morten; Chua, Katrin F; Mattson, Mark P; Croteau, Deborah L; Bohr, Vilhelm A

    2016-05-01

    Mitochondrial dysfunction is a hallmark of ageing, and mitochondrial maintenance may lead to increased healthspan. Emerging evidence suggests a crucial role for signalling from the nucleus to mitochondria (NM signalling) in regulating mitochondrial function and ageing. An important initiator of NM signalling is nuclear DNA damage, which accumulates with age and may contribute to the development of age-associated diseases. DNA damage-dependent NM signalling constitutes a network that includes nuclear sirtuins and controls genomic stability and mitochondrial integrity. Pharmacological modulation of NM signalling is a promising novel approach for the prevention and treatment of age-associated diseases. PMID:26956196

  16. Mitochondrial dysfunction in inherited renal disease and acute kidney injury.

    PubMed

    Emma, Francesco; Montini, Giovanni; Parikh, Samir M; Salviati, Leonardo

    2016-05-01

    Mitochondria are increasingly recognized as key players in genetic and acquired renal diseases. Most mitochondrial cytopathies that cause renal symptoms are characterized by tubular defects, but glomerular, tubulointerstitial and cystic diseases have also been described. For example, defects in coenzyme Q10 (CoQ10) biosynthesis and the mitochondrial DNA 3243 A>G mutation are important causes of focal segmental glomerulosclerosis in children and in adults, respectively. Although they sometimes present with isolated renal findings, mitochondrial diseases are frequently associated with symptoms related to central nervous system and neuromuscular involvement. They can result from mutations in nuclear genes that are inherited according to classic Mendelian rules or from mutations in mitochondrial DNA, which are transmitted according to more complex rules of mitochondrial genetics. Diagnosis of mitochondrial disorders involves clinical characterization of patients in combination with biochemical and genetic analyses. In particular, prompt diagnosis of CoQ10 biosynthesis defects is imperative because of their potentially reversible nature. In acute kidney injury (AKI), mitochondrial dysfunction contributes to the physiopathology of tissue injury, whereas mitochondrial biogenesis has an important role in the recovery of renal function. Potential therapies that target mitochondrial dysfunction or promote mitochondrial regeneration are being developed to limit renal damage during AKI and promote repair of injured tissue. PMID:26804019

  17. Mitochondrial RNA granules: Compartmentalizing mitochondrial gene expression.

    PubMed

    Jourdain, Alexis A; Boehm, Erik; Maundrell, Kinsey; Martinou, Jean-Claude

    2016-03-14

    In mitochondria, DNA replication, gene expression, and RNA degradation machineries coexist within a common nondelimited space, raising the question of how functional compartmentalization of gene expression is achieved. Here, we discuss the recently characterized "mitochondrial RNA granules," mitochondrial subdomains with an emerging role in the regulation of gene expression. PMID:26953349

  18. Contribution of dopamine to mitochondrial complex I inhibition and dopaminergic deficits caused by methylenedioxymethamphetamine in mice.

    PubMed

    Barros-Miñones, L; Goñi-Allo, B; Suquia, V; Beitia, G; Aguirre, N; Puerta, E

    2015-06-01

    Methylenedioxymethamphetamine (MDMA) causes a persistent loss of dopaminergic cell bodies in the substantia nigra of mice. Current evidence indicates that MDMA-induced neurotoxicity is mediated by oxidative stress probably due to the inhibition of mitochondrial complex I activity. In this study we investigated the contribution of dopamine (DA) to such effects. For this, we modulated the dopaminergic system of mice at the synthesis, uptake or metabolism levels. Striatal mitochondrial complex I activity was decreased 1 h after MDMA; an effect not observed in the striatum of DA depleted mice or in the hippocampus, a dopamine spare region. The DA precursor, L-dopa, caused a significant reduction of mitochondrial complex I activity by itself and exacerbated the dopaminergic deficits when combined with systemic MDMA. By contrast, no damage was observed when L-dopa was combined with intrastriatal injections of MDMA. On the other hand, dopamine uptake blockade using GBR 12909, inhibited both, the acute inhibition of complex I activity and the long-term dopaminergic toxicity caused by MDMA. Moreover, the inhibition of DA metabolism with the monoamine oxidase (MAO) inhibitor, pargyline, afforded a significant protection against MDMA-induced complex I inhibition and neurotoxicity. Taken together, these findings point to the formation of hydrogen peroxide subsequent to DA metabolism by MAO, rather than a direct DA-mediated mitochondrial complex I inhibition, and the contribution of a peripheral metabolite of MDMA, as the key steps in the chain of biochemical events leading to DA neurotoxicity caused by MDMA in mice. PMID:25666033

  19. A Small Volatile Bacterial Molecule Triggers Mitochondrial Dysfunction in Murine Skeletal Muscle

    PubMed Central

    Tzika, A. Aria; Constantinou, Caterina; Bandyopadhaya, Arunava; Psychogios, Nikolaos; Lee, Sangseok; Mindrinos, Michael; Martyn, J. A. Jeevendra; Tompkins, Ronald G.; Rahme, Laurence G.

    2013-01-01

    Mitochondria integrate distinct signals that reflect specific threats to the host, including infection, tissue damage, and metabolic dysfunction; and play a key role in insulin resistance. We have found that the Pseudomonas aeruginosa quorum sensing infochemical, 2-amino acetophenone (2-AA), produced during acute and chronic infection in human tissues, including in the lungs of cystic fibrosis (CF) patients, acts as an interkingdom immunomodulatory signal that facilitates pathogen persistence, and host tolerance to infection. Transcriptome results have led to the hypothesis that 2-AA causes further harm to the host by triggering mitochondrial dysfunction in skeletal muscle. As normal skeletal muscle function is essential to survival, and is compromised in many chronic illnesses, including infections and CF-associated muscle wasting, we here determine the global effects of 2-AA on skeletal muscle using high-resolution magic-angle-spinning (HRMAS), proton (1H) nuclear magnetic resonance (NMR) metabolomics, in vivo 31P NMR, whole-genome expression analysis and functional studies. Our results show that 2-AA when injected into mice, induced a biological signature of insulin resistance as determined by 1H NMR analysis-, and dramatically altered insulin signaling, glucose transport, and mitochondrial function. Genes including Glut4, IRS1, PPAR-γ, PGC1 and Sirt1 were downregulated, whereas uncoupling protein UCP3 was up-regulated, in accordance with mitochondrial dysfunction. Although 2-AA did not alter high-energy phosphates or pH by in vivo 31P NMR analysis, it significantly reduced the rate of ATP synthesis. This affect was corroborated by results demonstrating down-regulation of the expression of genes involved in energy production and muscle function, and was further validated by muscle function studies. Together, these results further demonstrate that 2-AA, acts as a mediator of interkingdom modulation, and likely effects insulin resistance associated with a

  20. p53 and Mitochondrial Function in Neurons

    PubMed Central

    Wang, David B.; Kinoshita, Chizuru; Kinoshita, Yoshito; Morrison, Richard S.

    2014-01-01

    The p53 tumor suppressor plays a central role in dictating cell survival and death as a cellular sensor for a myriad of stresses including DNA damage, oxidative and nutritional stress, ischemia and disruption of nucleolar function. Activation of p53-dependent apoptosis leads to mitochondrial apoptotic changes via the intrinsic and extrinsic pathways triggering cell death execution most notably by release of cytochrome c and activation of the caspase cascade. Although it was previously believed that p53 induces apoptotic mitochondrial changes exclusively through transcription-dependent mechanisms, recent studies suggest that p53 also regulates apoptosis via a transcription-independent action at the mitochondria. Recent evidence further suggests that p53 can regulate necrotic cell death and autophagic activity including mitophagy. An increasing number of cytosolic and mitochondrial proteins involved in mitochondrial metabolism and respiration are regulated by p53, which influences mitochondrial ROS production as well. Cellular redox homeostasis is also directly regulated by p53 through modified expression of pro- and anti-oxidant proteins. Proper regulation of mitochondrial size and shape through fission and fusion assures optimal mitochondrial bioenergetic function while enabling adequate mitochondrial transport to accommodate local energy demands unique to neuronal architecture. Abnormal regulation of mitochondrial dynamics has been increasingly implicated in neurodegeneration, where elevated levels of p53 may have a direct contribution as the expression of some fission/fusion proteins are directly regulated by p53. Thus, p53 may have a much wider influence on mitochondrial integrity and function than one would expect from its well-established ability to transcriptionally induce mitochondrial apoptosis. However, much of the evidence demonstrating that p53 can influence mitochondria through nuclear, cytosolic or intra-mitochondrial sites of action has yet to be

  1. Human Mitochondrial Protein Database

    National Institute of Standards and Technology Data Gateway

    SRD 131 Human Mitochondrial Protein Database (Web, free access)   The Human Mitochondrial Protein Database (HMPDb) provides comprehensive data on mitochondrial and human nuclear encoded proteins involved in mitochondrial biogenesis and function. This database consolidates information from SwissProt, LocusLink, Protein Data Bank (PDB), GenBank, Genome Database (GDB), Online Mendelian Inheritance in Man (OMIM), Human Mitochondrial Genome Database (mtDB), MITOMAP, Neuromuscular Disease Center and Human 2-D PAGE Databases. This database is intended as a tool not only to aid in studying the mitochondrion but in studying the associated diseases.

  2. Mitochondrial divergence between slow- and fast-aging garter snakes.

    PubMed

    Schwartz, Tonia S; Arendsee, Zebulun W; Bronikowski, Anne M

    2015-11-01

    Mitochondrial function has long been hypothesized to be intimately involved in aging processes--either directly through declining efficiency of mitochondrial respiration and ATP production with advancing age, or indirectly, e.g., through increased mitochondrial production of damaging free radicals with age. Yet we lack a comprehensive understanding of the evolution of mitochondrial genotypes and phenotypes across diverse animal models, particularly in species that have extremely labile physiology. Here, we measure mitochondrial genome-types and transcription in ecotypes of garter snakes (Thamnophis elegans) that are adapted to disparate habitats and have diverged in aging rates and lifespans despite residing in close proximity. Using two RNA-seq datasets, we (1) reconstruct the garter snake mitochondrial genome sequence and bioinformatically identify regulatory elements, (2) test for divergence of mitochondrial gene expression between the ecotypes and in response to heat stress, and (3) test for sequence divergence in mitochondrial protein-coding regions in these slow-aging (SA) and fast-aging (FA) naturally occurring ecotypes. At the nucleotide sequence level, we confirmed two (duplicated) mitochondrial control regions one of which contains a glucocorticoid response element (GRE). Gene expression of protein-coding genes was higher in FA snakes relative to SA snakes for most genes, but was neither affected by heat stress nor an interaction between heat stress and ecotype. SA and FA ecotypes had unique mitochondrial haplotypes with amino acid substitutions in both CYTB and ND5. The CYTB amino acid change (Isoleucine → Threonine) was highly segregated between ecotypes. This divergence of mitochondrial haplotypes between SA and FA snakes contrasts with nuclear gene-flow estimates, but correlates with previously reported divergence in mitochondrial function (mitochondrial oxygen consumption, ATP production, and reactive oxygen species consequences). PMID:26403677

  3. Oxidative stress and mitochondrial protein quality control in aging.

    PubMed

    Lionaki, Eirini; Tavernarakis, Nektarios

    2013-10-30

    Mitochondrial protein quality control incorporates an elaborate network of chaperones and proteases that survey the organelle for misfolded or unfolded proteins and toxic aggregates. Repair of misfolded or aggregated protein and proteolytic removal of irreversibly damaged proteins are carried out by the mitochondrial protein quality control system. Initial maturation and folding of the nuclear or mitochondrial-encoded mitochondrial proteins are mediated by processing peptidases and chaperones that interact with the protein translocation machinery. Mitochondrial proteins are subjected to cumulative oxidative damage. Thus, impairment of quality control processes may cause mitochondrial dysfunction. Aging has been associated with a marked decline in the effectiveness of mitochondrial protein quality control. Here, we present an overview of the chaperones and proteases involved in the initial folding and maturation of new, incoming precursor molecules, and the subsequent repair and removal of oxidized aggregated proteins. In addition, we highlight the link between mitochondrial protein quality control mechanisms and the aging process. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine. PMID:23563202

  4. Mitochondrial Biology and Neurological Diseases.

    PubMed

    Arun, Siddharth; Liu, Lei; Donmez, Gizem

    2016-01-01

    Mitochondria are extremely active organelles that perform a variety of roles in the cell including energy production, regulation of calcium homeostasis, apoptosis, and population maintenance through fission and fusion. Mitochondrial dysfunction in the form of oxidative stress and mutations can contribute to the pathogenesis of various neurodegenerative diseases such as Parkinson's (PD), Alzheimer's (AD), and Huntington's diseases (HD). Abnormalities of Complex I function in the electron transport chain have been implicated in some neurodegenerative diseases, inhibiting ATP production and generating reactive oxygen species that can cause major damage to mitochondria. Mutations in both nuclear and mitochondrial DNA can contribute to neurodegenerative disease, although the pathogenesis of these conditions tends to focus on nuclear mutations. In PD, nuclear genome mutations in the PINK1 and parkin genes have been implicated in neurodegeneration [1], while mutations in APP, PSEN1 and PSEN2 have been implicated in a variety of clinical symptoms of AD [5]. Mutant htt protein is known to cause HD [2]. Much progress has been made to determine some causes of these neurodegenerative diseases, though permanent treatments have yet to be developed. In this review, we discuss the roles of mitochondrial dysfunction in the pathogenesis of these diseases. PMID:26903445

  5. Mitochondrial Biology and Neurological Diseases

    PubMed Central

    Arun, Siddharth; Liu, Lei; Donmez, Gizem

    2016-01-01

    Mitochondria are extremely active organelles that perform a variety of roles in the cell including energy production, regulation of calcium homeostasis, apoptosis, and population maintenance through fission and fusion. Mitochondrial dysfunction in the form of oxidative stress and mutations can contribute to the pathogenesis of various neurodegenerative diseases such as Parkinson’s (PD), Alzheimer’s (AD), and Huntington’s diseases (HD). Abnormalities of Complex I function in the electron transport chain have been implicated in some neurodegenerative diseases, inhibiting ATP production and generating reactive oxygen species that can cause major damage to mitochondria Mutations in both nuclear and mitochondrial DNA can contribute to neurodegenerative disease, although the pathogenesis of these conditions tends to focus on nuclear mutations. In PD, nuclear genome mutations in the PINK1 and parkin genes have been implicated in neurodegeneration [1], while mutations in APP, PSEN1 and PSEN2 have been implicated in a variety of clinical symptoms of AD [5]. Mutant htt protein is known to cause HD [2]. Much progress has been made to determine some causes of these neurodegenerative diseases, though permanent treatments have yet to be developed. In this review, we discuss the roles of mitochondrial dysfunction in the pathogenesis of these diseases. PMID:26903445

  6. Segregation of naturally occurring mitochondrial DNA variants in a mini-pig model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Within cells and tissues, the maternally inherited mitochondrial genome (mtDNA) is present in multimeric form and can harbour naturally occurring variants. Whilst high variant load can cause mitochondrial disease, naturally occurring mtDNA variants likely persist at low levels across generations of ...

  7. PERSISTENT, BIOACCUMULATIVE, AND TOXIC POLLUTANTS (PBTS)

    EPA Science Inventory

    Article describes the class of compounds known as persistent, bioaccumulative, and toxic pollutants (known as PBTs), including the mechanisms responsible for ability to build up the food chain and for causing adverse health effects and ecosystem damage. Exposure to numerous PBTs ...

  8. [Mitochondrial disease and mitochondrial DNA depletion syndromes].

    PubMed

    Huang, Chin-Chang; Hsu, Chang-Huang

    2009-12-01

    Mitochondria is an intracellular double membrane-bound structure and it can provide energy for intracellular metabolism. The metabolism includes Krebs cycle, beta-oxidation and lipid synthesis. The density of mitochondria is different in various tissues dependent upon the demands of oxidative phosphorylation. Mitochondrial diseases can occur by defects either in mitochondrial DNA or nuclear DNA. Human mitochondrial DNA (mtDNA) encoding for 22 tRNAs, 2 rRNAs and 13 mRNAs that are translated in the mitochondria. Mitochondrial genetic diseases are most resulted from defects in the mtDNA which may be point mutations, deletions, or mitochondrial DNA depletion. These patterns of inheritance in mitochondrial diseases include sporadic, maternally inherited, or of Mendelian inheritance. Mitochondrial DNA depletion is caused by defects in the nuclear genes that are responsible for maintenance of integrity of mtDNA or deoxyribonucelotide pools and mtDNA biogenesis. The mtDNA depletion syndrome (MDS) includes the following categories: progressive external ophthalmoplegia (PEO), predominant myopathy, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), sensory-ataxic neuropathy, dysarthria, and ophthalmoplegia (SANDO) and hepato-encephalopathy. The most common tissues or organs involved in MDS and related disorders include the brain, liver and muscles. These involved genes are divided into two groups including 1) DNA polymerase gamma (POLG, POLG2) and Twinkle genes whose products function directly at the mtDNA replication fork, and 2) adenine nucleotide translocator 1, thymidine phosphorylase, thymidine kinase 2, deoxyguanosine kinase, ADP-forming succinyl-CoA synthetase ligase, MPV17 whose products supply the mitochondria with deoxyribonucleotide triphosphate pools needed for mtDNA replication, and possible mutation in the RRM2B gene. The development has provided new information about the importance of the biosynthetic pathway of the nucleotides for mtDNA replication

  9. N-acetylcysteine inhibits the upregulation of mitochondrial biogenesis genes in livers from rats fed ethanol chronically

    PubMed Central

    Caro, Andres A.; Bell, Matthew; Ejiofor, Shannon; Zurcher, Grant; Petersen, Dennis R.; Ronis, Martin J. J.

    2014-01-01

    Background Chronic ethanol administration to experimental animals induces hepatic oxidative stress and upregulates mitochondrial biogenesis. The mechanisms by which chronic ethanol upregulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic ethanol feeding. If our hypothesis is correct, co-administration of antioxidants should prevent upregulation of mitochondrial biogenesis genes. Methods Rats were fed an ethanol-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/day; control rats were administered isocaloric diets where carbohydrates substituted for ethanol calories. Results Ethanol administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and GSH/GSSG ratio. These effects were inhibited by co-administration of ethanol and NAC. Chronic ethanol increased the expression of mitochondrial biogenesis genes including peroxisome proliferator activated receptor gamma-coactivator-1 alpha and mitochondrial transcription factor A, and mitochondrial DNA; co-administration of ethanol and NAC prevented these effects. Chronic ethanol administration was associated with decreased mitochondrial mass, inactivation and depletion of mitochondrial complex I and complex IV, and increased hepatic mitochondrial oxidative damage, effects that were not prevented by NAC. Conclusions These results suggest that oxidative stress caused by chronic ethanol triggered the upregulation of mitochondrial biogenesis genes in rat liver, because an antioxidant such as NAC prevented both effects. Because NAC did not prevent liver mitochondrial oxidative damage, extra-mitochondrial effects of reactive oxygen species may regulate mitochondrial biogenesis. In spite of the induction of hepatic mitochondrial biogenesis genes by

  10. Data on mitochondrial function in skeletal muscle of old mice in response to different exercise intensity.

    PubMed

    Kang, Chounghun; Lim, Wonchung

    2016-06-01

    Endurance exercise is securely linked to muscle metabolic adaptations including enhanced mitochondrial function ("Effects of exercise on mitochondrial oxygen uptake and respiratory enzyme activity in skeletal muscle" [1], "Effects of exercise on mitochondrial content and function in aging human skeletal muscle" [2]). However, the link between exercise intensity and mitochondrial function in aging muscle has not been fully investigated. In order to understand how strenuous exercise affects mitochondrial function in aged mice, male C57BL/6 mice at age 24 months were randomly assigned to 3 groups: non-exercise (NE), low-intensity (LE) and high-intensity treadmill exercise group (HE). Mitochondrial complex activity and respiration were measured to evaluate mitochondrial function in mouse skeletal muscle. The data described here are related to the research article entitled "Strenuous exercise induces mitochondrial damage in skeletal muscle of old mice" [3]. PMID:27222846

  11. Data on mitochondrial function in skeletal muscle of old mice in response to different exercise intensity

    PubMed Central

    Kang, Chounghun; Lim, Wonchung

    2016-01-01

    Endurance exercise is securely linked to muscle metabolic adaptations including enhanced mitochondrial function (“Effects of exercise on mitochondrial oxygen uptake and respiratory enzyme activity in skeletal muscle” [1], “Effects of exercise on mitochondrial content and function in aging human skeletal muscle” [2]). However, the link between exercise intensity and mitochondrial function in aging muscle has not been fully investigated. In order to understand how strenuous exercise affects mitochondrial function in aged mice, male C57BL/6 mice at age 24 months were randomly assigned to 3 groups: non-exercise (NE), low-intensity (LE) and high-intensity treadmill exercise group (HE). Mitochondrial complex activity and respiration were measured to evaluate mitochondrial function in mouse skeletal muscle. The data described here are related to the research article entitled “Strenuous exercise induces mitochondrial damage in skeletal muscle of old mice” [3]. PMID:27222846

  12. Free redicals and tissue damage produced by exercise

    SciTech Connect

    Davies, K.J.A.; Quintanilha, A.T.; Brooks, G.A.; Packer, L.

    1982-08-31

    We report a two- to three-fold increase in free radical (R/sup 0/) concentrations of muscle and liver following exercise to exhaustive. Exhaustive exercise also resulted in decreased mitochondrial respiratory control, loss of sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) integrity, and increased levels of lipid peroxidation products. Free radical concentrations, lipid peroxidation, mitochondrial and SR, ER, and mitochondrial damage were similar in exercise exhausted control animals and non-exercised vitamin E deficient animals, suggesting the possibility of a common R/sup 0/ dependent damage process. In agreement with previous work showing that exercise endurance capacity is largely determined by the functional mitochondrial content of muscle (1-4), vitamin E deficient animals endurance was 40% lower than that of controls. The results suggest that R/sup 0/ induced damage may provide a stimulus to the mitochondrial biogenesis which results from endurance training.

  13. Cytoprotection by the Modulation of Mitochondrial Electron Transport Chain: The Emerging Role of Mitochondrial STAT3

    PubMed Central

    Szczepanek, Karol; Chen, Qun; Larner, Andrew C.; Lesnefsky, Edward J.

    2011-01-01

    The down regulation of mitochondrial electron transport is an emerging mechanism of cytoprotective intervention that is effective in pathologic settings such as myocardial ischemia and reperfusion when the continuation of mitochondrial respiration produces reactive oxygen species, mitochondrial calcium overload, and the release of cytochrome c to activate cell death programs. The initial target of deranged electron transport is the mitochondria themselves. In the first part of this review, we describe this concept and summarize different approaches used to regulate mitochondrial respiration by targeting complex I as a proximal site in the electron transport chain (ETC) in order to favor the cytoprotection. The second part of the review highlights the emerging role of signal transducer and activator of transcription 3 (STAT3) in the direct, non-transcriptional regulation of ETC, as an example of a genetic approach to modulate respiration. Recent studies indicate that a pool of STAT3 resides in the mitochondria where it is necessary for the maximal activity of complexes I and II of the electron transport chain (ETC). The over expression of mitochondrial-targeted STAT3 results in a partial blockade of electron transport at complexes I and II that does not impair mitochondrial membrane potential nor enhance the production of reactive oxygen species (ROS). The targeting of transcriptionally-inactive STAT3 to mitochondria attenuates damage to mitochondria during cell stress, resulting in decreased production of ROS and retention of cytochrome c by mitochondria. The overexpression of STAT3 targeted to mitochondria unveils a novel protective approach mediated by modulation of mitochondrial respiration that is independent of STAT3 transcriptional activity. The limitation of mitochondrial respiration under pathologic circumstances can be approached by activation and over expression of endogenous signaling mechanisms in addition to pharmacologic means. The regulation of

  14. Mitochondrial phospholipids: role in mitochondrial function.

    PubMed

    Mejia, Edgard M; Hatch, Grant M

    2016-04-01

    Mitochondria are essential components of eukaryotic cells and are involved in a diverse set of cellular processes that include ATP production, cellular signalling, apoptosis and cell growth. These organelles are thought to have originated from a symbiotic relationship between prokaryotic cells in an effort to provide a bioenergetic jump and thus, the greater complexity observed in eukaryotes (Lane and Martin 2010). Mitochondrial processes are required not only for the maintenance of cellular homeostasis, but also allow cell to cell and tissue to tissue communication (Nunnari and Suomalainen 2012). Mitochondrial phospholipids are important components of this system. Phospholipids make up the characteristic outer and inner membranes that give mitochondria their shape. In addition, these membranes house sterols, sphingolipids and a wide variety of proteins. It is the phospholipids that also give rise to other characteristic mitochondrial structures such as cristae (formed from the invaginations of the inner mitochondrial membrane), the matrix (area within cristae) and the intermembrane space (IMS) which separates the outer mitochondrial membrane (OMM) and inner mitochondrial membrane (IMM). Phospholipids are the building blocks that make up these structures. However, the phospholipid composition of the OMM and IMM is unique in each membrane. Mitochondria are able to synthesize some of the phospholipids it requires, but the majority of cellular lipid biosynthesis takes place in the endoplasmic reticulum (ER) in conjunction with the Golgi apparatus (Fagone and Jackowski 2009). In this review, we will focus on the role that mitochondrial phospholipids play in specific cellular functions and discuss their biosynthesis, metabolism and transport as well as the differences between the OMM and IMM phospholipid composition. Finally, we will focus on the human diseases that result from disturbances to mitochondrial phospholipids and the current research being performed to help

  15. Mitochondrial allostatic load puts the 'gluc' back in glucocorticoids.

    PubMed

    Picard, Martin; Juster, Robert-Paul; McEwen, Bruce S

    2014-05-01

    The link between chronic psychosocial and metabolic stress and the pathogenesis of disease has been extensively documented. Nevertheless, the cellular mechanisms by which stressful life experiences and their associated primary neuroendocrine mediators cause biological damage and increase disease risk remain poorly understood. The allostatic load model of chronic stress focuses on glucocorticoid dysregulation. In this Perspectives, we expand upon the metabolic aspects of this model-particularly glucose imbalance-and propose that mitochondrial dysfunction constitutes an early, modifiable target of chronic stress and stress-related health behaviours. Central to this process is mitochondrial regulation of energy metabolism and cellular signalling. Chronically elevated glucose levels damage both mitochondria and mitochondrial DNA, generating toxic products that can promote systemic inflammation, alter gene expression and hasten cell ageing. Consequently, the concept of 'mitochondrial allostatic load' defines the deleterious structural and functional changes that mitochondria undergo in response to elevated glucose levels and stress-related pathophysiology. PMID:24663223

  16. Hypoxamirs and Mitochondrial Metabolism

    PubMed Central

    Cottrill, Katherine A.; Chan, Stephen Y.

    2014-01-01

    Abstract Significance: Chronic hypoxia can drive maladaptive responses in numerous organ systems, leading to a multitude of chronic mammalian diseases. Oxygen homeostasis is intimately linked with mitochondrial metabolism, and dysfunction in these systems can combine to form the backbone of hypoxic-ischemic injury in multiple tissue beds. Increased appreciation of the crucial roles of hypoxia-associated miRNA (hypoxamirs) in metabolism adds a new dimension to our understanding of the regulation of hypoxia-induced disease. Recent Advances: Myriad factors related to glycolysis (e.g., aldolase A and hexokinase II), tricarboxylic acid cycle function (e.g., glutaminase and iron-sulfur cluster assembly protein 1/2), and apoptosis (e.g., p53) have been recently implicated as targets of hypoxamirs. In addition, several hypoxamirs have been implicated in the regulation of the master transcription factor of hypoxia, hypoxia-inducible factor-1α, clarifying how the cellular program of hypoxia is sustained and resolved. Critical Issues: Central to the discussion of metabolic change in hypoxia is the Warburg effect, a shift toward anaerobic metabolism that persists after normal oxygen levels have been restored. Many newly discovered targets of hypoxia-driven microRNA converge on pathways known to be involved in this pathological phenomenon and the apoptosis-resistant phenotype associated with it. Future Directions: The often synergistic functions of miRNA may make them ideal therapeutic targets. The use of antisense inhibitors is currently being considered in diseases in which hypoxia and metabolic dysregulation predominate. In addition, exploration of pleiotripic miRNA functions will likely continue to offer unique insights into the mechanistic relationships of their downstream target pathways and associated hypoxic phenotypes. Antioxid. Redox Signal. 21, 1189–1201. PMID:24111795

  17. Mitophagy plays a central role in mitochondrial ageing.

    PubMed

    Diot, Alan; Morten, Karl; Poulton, Joanna

    2016-08-01

    The mechanisms underlying ageing have been discussed for decades, and advances in molecular and cell biology of the last three decades have accelerated research in this area. Over this period, it has become clear that mitochondrial function, which plays a major role in many cellular pathways from ATP production to nuclear gene expression and epigenetics alterations, declines with age. The emerging concepts suggest novel mechanisms, involving mtDNA quality, mitochondrial dynamics or mitochondrial quality control. In this review, we discuss the impact of mitochondria in the ageing process, the role of mitochondria in reactive oxygen species production, in nuclear gene expression, the accumulation of mtDNA damage and the importance of mitochondrial dynamics and recycling. Declining mitophagy (mitochondrial quality control) may be an important component of human ageing. PMID:27352213

  18. Exercise-induced mitochondrial dysfunction: a myth or reality?

    PubMed

    Ostojic, Sergej M

    2016-08-01

    Beneficial effects of physical activity on mitochondrial health are well substantiated in the scientific literature, with regular exercise improving mitochondrial quality and quantity in normal healthy population, and in cardiometabolic and neurodegenerative disorders and aging. However, several recent studies questioned this paradigm, suggesting that extremely heavy or exhaustive exercise fosters mitochondrial disturbances that could permanently damage its function in health and disease. Exercise-induced mitochondrial dysfunction (EIMD) might be a key proxy for negative outcomes of exhaustive exercise, being a pathophysiological substrate of heart abnormalities, chronic fatigue syndrome (CFS) or muscle degeneration. Here, we overview possible factors that mediate negative effects of exhaustive exercise on mitochondrial function and structure, and put forward alternative solutions for the management of EIMD. PMID:27389587

  19. Kinetics and specificity of paternal mitochondrial elimination in Caenorhabditis elegans.

    PubMed

    Wang, Yang; Zhang, Yi; Chen, Lianwan; Liang, Qian; Yin, Xiao-Ming; Miao, Long; Kang, Byung-Ho; Xue, Ding

    2016-01-01

    In most eukaryotes, mitochondria are inherited maternally. The autophagy process is critical for paternal mitochondrial elimination (PME) in Caenorhabditis elegans, but how paternal mitochondria, but not maternal mitochondria, are selectively targeted for degradation is poorly understood. Here we report that mitochondrial dynamics have a profound effect on PME. A defect in fission of paternal mitochondria delays PME, whereas a defect in fusion of paternal mitochondria accelerates PME. Surprisingly, a defect in maternal mitochondrial fusion delays PME, which is reversed by a fission defect in maternal mitochondria or by increasing maternal mitochondrial membrane potential using oligomycin. Electron microscopy and tomography analyses reveal that a proportion of maternal mitochondria are compromised when they fail to fuse normally, leading to their competition for the autophagy machinery with damaged paternal mitochondria and delayed PME. Our study indicates that mitochondrial dynamics play a critical role in regulating both the kinetics and the specificity of PME. PMID:27581092

  20. Three-Dimensional Normal Human Neural Progenitor Tissue-Like Assemblies: A Model for Persistent Varicell-Zoster Virus Infection and Platform to Study Viral Infectivity and Oxidative Stress and Damage

    NASA Technical Reports Server (NTRS)

    Goodwin, T. J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

    2014-01-01

    The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpesvirus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex threedimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6].

  1. Response: persistent perplexities.

    PubMed

    Radin, M J

    2001-09-01

    This response to the preceding five articles highlights the stubborn persistence of the philosophical perplexities surrounding commodification in the realm of medicine and biotechnology. PMID:11700685

  2. Mitochondrial threshold effects.

    PubMed Central

    Rossignol, Rodrigue; Faustin, Benjamin; Rocher, Christophe; Malgat, Monique; Mazat, Jean-Pierre; Letellier, Thierry

    2003-01-01

    The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the 'phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the 'biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a 'translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases. PMID:12467494

  3. MYC and Mitochondrial Biogenesis

    PubMed Central

    Morrish, Fionnuala; Hockenbery, David

    2014-01-01

    Mitochondria, the powerhouses of the cell, face two imperatives concerning biogenesis. The first is the requirement for dividing cells to replicate their mitochondrial content by growth of existing mitochondria. The second is the dynamic regulation of mitochondrial content in response to organismal and cellular cues (e.g., exercise, caloric restriction, energy status, temperature). MYC provides the clearest example of a programmed expansion of mitochondrial content linked to the cell cycle. As an oncogene, MYC also presents intriguing questions about the role of its mitochondrial targets in cancer-related phenotypes, such as the Warburg effect and MYC-dependent apoptosis. PMID:24789872

  4. Regulation of Mitochondrial Transport in Neurons

    PubMed Central

    Lin, Mei-Yao; Sheng, Zu-Hang

    2015-01-01

    Mitochondria are cellular power plants that supply ATP to power various biological activities essential for neuronal growth, survival, and function. Due to unique morphological features, neurons face exceptional challenges to maintain ATP and Ca2+ homeostasis. Neurons require specialized mechanisms distributing mitochondria to distal areas where energy and Ca2+ buffering are in high demand, such as synapses and axonal branches. These distal compartments also undergo development- and activity-dependent remodeling, thereby altering mitochondrial trafficking and distribution. Mitochondria move bi-directionally, pause briefly, and move again, frequently changing direction. In mature neurons, only one-third of axonal mitochondria are motile. Stationary mitochondria serve as local energy sources and buffer intracellular Ca2+. The balance between motile and stationary mitochondria responds quickly to changes in axonal and synaptic physiology. Furthermore, neurons are postmitotic cells surviving for the lifetime of the organism; thus, mitochondria need to be removed when they become aged or dysfunction. Mitochondria also alter their motility under stress conditions or when their integrity is impaired. Therefore, regulation of mitochondrial transport is essential to meet altered metabolic requirements and to remove aged and damaged mitochondria or replenish healthy ones to distal terminals. Defects in mitochondrial transport and altered distribution are implicated in the pathogenesis of several major neurological disorders. Thus, research into the mechanisms regulating mitochondrial motility is an important emerging frontier in neurobiology. This short review provides an updated overview on motor-adaptor machineries that drive and regulate mitochondrial transport and docking receptors that anchor axonal mitochondria in response to the changes in synaptic activity, metabolic requirement, and altered mitochondrial integrity. The review focuses on microtubule (MT

  5. Mitochondrial Proteases as Emerging Pharmacological Targets.

    PubMed

    Gibellini, Lara; De Biasi, Sara; Nasi, Milena; Iannone, Anna; Cossarizza, Andrea; Pinti, Marcello

    2016-01-01

    The preservation of mitochondrial function and integrity is critical for cell viability. Under stress conditions, unfolded, misfolded or damaged proteins accumulate in a certain compartment of the organelle, interfering with oxidative phosphorylation and normal mitochondrial functions. In stress conditions, several mechanisms, including mitochondrial unfolded protease response (UPRmt), fusion and fission, and mitophagy are engaged to restore normal proteostasis of the organelle. Mitochondrial proteases are a family of more than 20 enzymes that not only are involved in the UPRmt, but actively participate at multiple levels in the stress-response system. Alterations in their expression levels, or mutations that determine loss or gain of function of these proteases deeply impair mitochondrial functionality and can be associated with the onset of inherited diseases, with the development of neurodegenerative disorders and with the process of carcinogenesis. In this review, we focus our attention on six of them, namely CLPP, HTRA2 and LONP1, by analysing the current knowledge about their functions, their involvement in the pathogenesis of human diseases, and the compounds currently available for inhibiting their functions. PMID:26831646

  6. MAVS maintains mitochondrial homeostasis via autophagy

    PubMed Central

    Sun, Xiaofeng; Sun, Liwei; Zhao, Yuanyuan; Li, Ying; Lin, Wei; Chen, Dahua; Sun, Qinmiao

    2016-01-01

    Mitochondrial antiviral signalling protein (MAVS) acts as a critical adaptor protein to transduce antiviral signalling by physically interacting with activated RIG-I and MDA5 receptors. MAVS executes its functions at the outer membrane of mitochondria to regulate downstream antiviral signalling, indicating that the mitochondria provides a functional platform for innate antiviral signalling transduction. However, little is known about whether and how MAVS-mediated antiviral signalling contributes to mitochondrial homeostasis. Here we show that the activation of MAVS is sufficient to induce autophagic signalling, which may mediate the turnover of the damaged mitochondria. Importantly, we find MAVS directly interacts with LC3 through its LC3-binding motif ‘YxxI’, suggesting that MAVS might act as an autophagy receptor to mediate mitochondrial turnover upon excessive activation of RLR signalling. Furthermore, we provide evidence that both MAVS self-aggregation and its interaction with TRAF2/6 proteins are important for MAVS-mediated mitochondrial turnover. Collectively, our findings suggest that MAVS acts as a potential receptor for mitochondria-associated autophagic signalling to maintain mitochondrial homeostasis. PMID:27551434

  7. MAVS maintains mitochondrial homeostasis via autophagy.

    PubMed

    Sun, Xiaofeng; Sun, Liwei; Zhao, Yuanyuan; Li, Ying; Lin, Wei; Chen, Dahua; Sun, Qinmiao

    2016-01-01

    Mitochondrial antiviral signalling protein (MAVS) acts as a critical adaptor protein to transduce antiviral signalling by physically interacting with activated RIG-I and MDA5 receptors. MAVS executes its functions at the outer membrane of mitochondria to regulate downstream antiviral signalling, indicating that the mitochondria provides a functional platform for innate antiviral signalling transduction. However, little is known about whether and how MAVS-mediated antiviral signalling contributes to mitochondrial homeostasis. Here we show that the activation of MAVS is sufficient to induce autophagic signalling, which may mediate the turnover of the damaged mitochondria. Importantly, we find MAVS directly interacts with LC3 through its LC3-binding motif 'YxxI', suggesting that MAVS might act as an autophagy receptor to mediate mitochondrial turnover upon excessive activation of RLR signalling. Furthermore, we provide evidence that both MAVS self-aggregation and its interaction with TRAF2/6 proteins are important for MAVS-mediated mitochondrial turnover. Collectively, our findings suggest that MAVS acts as a potential receptor for mitochondria-associated autophagic signalling to maintain mitochondrial homeostasis. PMID:27551434

  8. Effects of dietary fatty acids on mitochondrial phospholipid compositions, oxidative status and mitochondrial gene expression of zebrafish at different ages.

    PubMed

    Betancor, M B; Almaida-Pagán, P F; Hernández, A; Tocher, D R

    2015-10-01

    Mitochondrial decay is generally associated with impairment in the organelle bioenergetics function and increased oxidative stress, and it appears that deterioration of mitochondrial inner membrane phospholipids (PL) and accumulation of mitochondrial DNA (mtDNA) mutations are among the main mechanisms involved in this process. In the present study, mitochondrial membrane PL compositions, oxidative status (TBARS content and SOD activity) and mtDNA gene expression of muscle and liver were analyzed in zebrafish fed two diets with lipid supplied either by rapeseed oil (RO) or a blend 60:40 of RO and DHA500 TG oil (DHA). Two feeding trials were performed using zebrafish from the same population of two ages (8 and 21 months). Dietary FA composition affected fish growth in 8-month-old animals, which could be related to an increase in stress promoted by diet composition. Lipid peroxidation was considerably higher in mitochondria of 8-month-old zebrafish fed the DHA diet than in animals fed the RO diet. This could indicate higher oxidative damage to mitochondrial lipids, very likely due to increased incorporation of DHA in PL of mitochondrial membranes. Lipids would be among the first molecules affected by mitochondrial reactive oxygen species, and lipid peroxidation could propagate oxidative reactions that would damage other molecules, including mtDNA. Mitochondrial lipid peroxidation and gene expression of 21-month-old fish showed lower responsiveness to diet composition than those of younger fish. Differences found in the effect of diet composition on mitochondrial lipids between the two age groups could be indicating age-related changes in the ability to maintain structural homeostasis of mitochondrial membranes. PMID:26156499

  9. Three-Dimensional Normal Human Neutral Progenitor Tissue-Like Assemblies: A Model for Persistent Varicella-Zoster Virus Infection and Platform to Study Oxidate Stress and Damage in Multiple Hit Scenarios

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

    2014-01-01

    The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpes virus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex three-dimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6]. By combining the RFs of microgravity, radiation, and viral infection we will demonstrate that living in the space environment leads to significant physiological consequences for the peripheral and subsequently the central nervous system (PNS, CNS) associated with OSaD generation and consequentially endangers long-duration and exploration-class missions.

  10. Betaine is a positive regulator of mitochondrial respiration

    SciTech Connect

    Lee, Icksoo

    2015-01-09

    Highlights: • Betaine enhances cytochrome c oxidase activity and mitochondrial respiration. • Betaine increases mitochondrial membrane potential and cellular energy levels. • Betaine’s anti-tumorigenic effect might be due to a reversal of the Warburg effect. - Abstract: Betaine protects cells from environmental stress and serves as a methyl donor in several biochemical pathways. It reduces cardiovascular disease risk and protects liver cells from alcoholic liver damage and nonalcoholic steatohepatitis. Its pretreatment can rescue cells exposed to toxins such as rotenone, chloroform, and LiCl. Furthermore, it has been suggested that betaine can suppress cancer cell growth in vivo and in vitro. Mitochondrial electron transport chain (ETC) complexes generate the mitochondrial membrane potential, which is essential to produce cellular energy, ATP. Reduced mitochondrial respiration and energy status have been found in many human pathological conditions including aging, cancer, and neurodegenerative disease. In this study we investigated whether betaine directly targets mitochondria. We show that betaine treatment leads to an upregulation of mitochondrial respiration and cytochrome c oxidase activity in H2.35 cells, the proposed rate limiting enzyme of ETC in vivo. Following treatment, the mitochondrial membrane potential was increased and cellular energy levels were elevated. We propose that the anti-proliferative effects of betaine on cancer cells might be due to enhanced mitochondrial function contributing to a reversal of the Warburg effect.

  11. Zinc and calcium modulate mitochondrial redox state and morphofunctional integrity.

    PubMed

    Sharaf, Mahmoud S; van den Heuvel, Michael R; Stevens, Don; Kamunde, Collins

    2015-07-01

    Zinc and calcium have highly interwoven functions that are essential for cellular homeostasis. Here we first present a novel real-time flow cytometric technique to measure mitochondrial redox state and show it is modulated by zinc and calcium, individually and combined. We then assess the interactions of zinc and calcium on mitochondrial H2O2 production, membrane potential (ΔΨm), morphological status, oxidative phosphorylation (OXPHOS), complex I activity, and structural integrity. Whereas zinc at low doses and both cations at high doses individually and combined promoted H2O2 production, the two cations individually did not alter mitochondrial redox state. However, when combined at low and high doses the two cations synergistically suppressed and promoted, respectively, mitochondrial shift to a more oxidized state. Surprisingly, the antioxidants vitamin E and N-acetylcysteine showed pro-oxidant activity at low doses, whereas at high antioxidant doses NAC inhibited OXPHOS and dyscoupled mitochondria. Individually, zinc was more potent than calcium in inhibiting OXPHOS, whereas calcium more potently dissipated the ΔΨm and altered mitochondrial volume and ultrastructure. The two cations synergistically inhibited OXPHOS but antagonistically dissipated ΔΨm and altered mitochondrial volume and morphology. Overall, our study highlights the importance of zinc and calcium in mitochondrial redox regulation and functional integrity. Importantly, we uncovered previously unrecognized bidirectional interactions of zinc and calcium that reveal distinctive foci for modulating mitochondrial function in normal and disease states because they are potentially protective or damaging depending on conditions. PMID:25841782

  12. Mitochondrial syndromes with leukoencephalopathies.

    PubMed

    Wong, Lee-Jun C

    2012-02-01

    White matter involvement has recently been recognized as a common feature in patients with multisystem mitochondrial disorders that may be caused by molecular defects in either the mitochondrial genome or the nuclear genes. It was first realized in classical mitochondrial syndromes associated with mitochondrial DNA (mtDNA) mutations, such as mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), Leigh's disease, and Kearns-Sayre's syndrome. Deficiencies in respiratory chain complexes I, II, IV, and V often cause Leigh's disease; most of them are due to nuclear defects that may lead to severe early-onset leukoencephalopathies. Defects in a group of nuclear genes involved in the maintenance of mtDNA integrity may also affect the white matter; for example, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) caused by thymidine phosphorylase deficiency, Navajo neurohepatopathy (NNH) due to MPV17 mutations, and Alpers syndrome due to defects in DNA polymerase gamma (POLG). More recently, leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) has been reported to be caused by autosomal recessive mutations in a mitochondrial aspartyl-tRNA synthetase, DARS2 gene. A patient with leukoencephalopathy and neurologic complications in addition to a multisystem involvement warrants a complete evaluation for mitochondrial disorders. A definite diagnosis may be achieved by molecular analysis of candidate genes based on the biochemical, clinical, and imaging results. PMID:22422207

  13. Myoclonus in mitochondrial disorders.

    PubMed

    Mancuso, Michelangelo; Orsucci, Daniele; Angelini, Corrado; Bertini, Enrico; Catteruccia, Michela; Pegoraro, Elena; Carelli, Valerio; Valentino, Maria L; Comi, Giacomo P; Minetti, Carlo; Bruno, Claudio; Moggio, Maurizio; Ienco, Elena Caldarazzo; Mongini, Tiziana; Vercelli, Liliana; Primiano, Guido; Servidei, Serenella; Tonin, Paola; Scarpelli, Mauro; Toscano, Antonio; Musumeci, Olimpia; Moroni, Isabella; Uziel, Graziella; Santorelli, Filippo M; Nesti, Claudia; Filosto, Massimiliano; Lamperti, Costanza; Zeviani, Massimo; Siciliano, Gabriele

    2014-05-01

    Myoclonus is a possible manifestation of mitochondrial disorders, and its presence is considered, in association with epilepsy and the ragged red fibers, pivotal for the syndromic diagnosis of MERRF (myoclonic epilepsy with ragged red fibers). However, its prevalence in mitochondrial diseases is not known. The aims of this study are the evaluation of the prevalence of myoclonus in a big cohort of mitochondrial patients and the clinical characterization of these subjects. Based on the database of the "Nation-wide Italian Collaborative Network of Mitochondrial Diseases," we reviewed the clinical and molecular data of mitochondrial patients with myoclonus among their clinical features. Myoclonus is a rather uncommon clinical feature of mitochondrial diseases (3.6% of 1,086 patients registered in our database). It is not strictly linked to a specific genotype or phenotype, and only 1 of 3 patients with MERRF harbors the 8344A>G mutation (frequently labeled as "the MERRF mutation"). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ataxia. In a myoclonic patient, evidences of mitochondrial dysfunction must be investigated, even though myoclonus is not a common sign of mitochondriopathy. Clinical, histological, and biochemical data may predict the finding of a mitochondrial or nuclear DNA mutation. Finally, this study reinforces the notion that myoclonus is not inextricably linked to epilepsy in MERRF patients, and therefore the term "myoclonic epilepsy" seems inadequate and potentially misleading. PMID:24510442

  14. The human mitochondrial transcriptome

    PubMed Central

    Mercer, Tim R.; Neph, Shane; Dinger, Marcel E.; Crawford, Joanna; Smith, Martin A.; Shearwood, Anne-Marie J.; Haugen, Eric; Bracken, Cameron P.; Rackham, Oliver; Stamatoyannopoulos, John A.; Filipovska, Aleksandra; Mattick, John S.

    2011-01-01

    Summary The human mitochondrial genome comprises a distinct genetic system transcribed as precursor polycistronic transcripts that are subsequently cleaved to generate individual mRNAs, tRNAs and rRNAs. Here we provide a comprehensive analysis of the human mitochondrial transcriptome across multiple cell lines and tissues. Using directional deep sequencing and parallel analysis of RNA ends, we demonstrate wide variation in mitochondrial transcript abundance and precisely resolve transcript processing and maturation events. We identify previously undescribed transcripts, including small RNAs, and observe the enrichment of several nuclear RNAs in mitochondria. Using high-throughput in vivo DNaseI footprinting, we establish the global profile of DNA-binding protein occupancy across the mitochondrial genome at single nucleotide resolution, revealing regulatory features at mitochondrial transcription initiation sites and functional insights into disease-associated variants. This integrated analysis of the mitochondrial transcriptome reveals unexpected complexity in the regulation, expression, and processing of mitochondrial RNA, and provides a resource for future studies of mitochondrial function (accessed at mitochondria.matticklab.com). PMID:21854988

  15. Novel p75 neurotrophin receptor ligand stabilizes neuronal calcium, preserves mitochondrial movement and protects against HIV associated neuropathogenesis.

    PubMed

    Meeker, Rick B; Poulton, Winona; Clary, Gillian; Schriver, Michael; Longo, Frank M

    2016-01-01

    Human immunodeficiency virus (HIV) rapidly penetrates into the brain and establishes a persistent infection of macrophages/microglia. Activation of these cells by HIV results in the secretion of soluble factors that destabilize neuronal calcium homeostasis, encourage oxidative stress and result in neural damage. This damage is thought to underlie the cognitive-motor dysfunction that develops in many HIV-infected patients. Studies have suggested that neurotrophins may protect neurons from the toxic effects of HIV-associated proteins. To better understand the pathogenic mechanisms and the neuroprotective potential of neurotrophin ligands, we evaluated neuronal damage, calcium homeostasis and mitochondrial functions after exposure of cultured rat neurons directly to HIV gp120 or to conditioned medium from human monocyte-derived macrophages treated with gp120. We then assessed the ability of a new non-peptide p75 neurotrophin receptor ligand, LM11A-31, to stabilize calcium homeostasis and prevent the development of pathology. Each toxic challenge resulted in a delayed accumulation of intracellular calcium coupled to a decrease in the rate of calcium clearance from the cell. The delayed calcium accumulation correlated with the development of focal dendritic swellings (beading), cytoskeletal damage and impaired movement of mitochondria. Addition of LM11A-31 to the cultures at nanomolar concentrations eliminated cell death, significantly reduced the pathology, suppressed the delayed accumulation of calcium and restored mitochondrial movements. The potent neuroprotection and the stabilization of calcium homeostasis indicate that LM11A-31 may have excellent potential for the treatment of HIV-associated neurodegeneration. PMID:26424436

  16. Mitochondrial Therapeutics for Cardioprotection

    PubMed Central

    Carreira, Raquel S.; Lee, Pamela; Gottlieb, Roberta A.

    2013-01-01

    Mitochondria represent approximately one-third of the mass of the heart and play a critical role in maintaining cellular function—however, they are also a potent source of free radicals and pro-apoptotic factors. As such, maintaining mitochondrial homeostasis is essential to cell survival. As the dominant source of ATP, continuous quality control is mandatory to ensure their ongoing optimal function. Mitochondrial quality control is accomplished by the dynamic interplay of fusion, fission, autophagy, and mitochondrial biogenesis. This review examines these processes in the heart and considers their role in the context of ischemia-reperfusion injury. Interventions that modulate mitochondrial turnover, including pharmacologic agents, exercise, and caloric restriction are discussed as a means to improve mitochondrial quality control, ameliorate cardiovascular dysfunction, and enhance longevity. PMID:21718247

  17. Calpastatin overexpression reduces oxidative stress-induced mitochondrial impairment and cell death in human neuroblastoma SH-SY5Y cells by decreasing calpain and calcineurin activation, induction of mitochondrial fission and destruction of mitochondrial fusion.

    PubMed

    Tangmansakulchai, Kulvadee; Abubakar, Zuroida; Kitiyanant, Narisorn; Suwanjang, Wilasinee; Leepiyasakulchai, Chaniya; Govitrapong, Piyarat; Chetsawang, Banthit

    2016-09-01

    Calpain is an intracellular Ca(2+)-dependent protease, and the activation of calpain has been implicated in neurodegenerative diseases. Calpain activity can be regulated by calpastatin, an endogenous specific calpain inhibitor. Several lines of evidence have demonstrated a potential role of calpastatin in preventing calpain-mediated pathogenesis. Additionally, several studies have revealed that calpain activation and mitochondrial damage are involved in the cell death process; however, recent evidence has not clearly indicated a neuroprotective mechanism of calpastatin against calpain-dependent mitochondrial impairment in the process of neuronal cell death. Therefore, the purpose of this study was to investigate the potential ability of calpastatin to inhibit calpain activation and mitochondrial impairment in oxidative stress-induced neuron degeneration. Calpastatin was stably overexpressed in human neuroblastoma SH-SY5Y cells. In non-calpastatin overexpressing SH-SY5Y cells, hydrogen peroxide significantly decreased cell viability, superoxide dismutase activity, mitochondrial membrane potential, ATP production and mitochondrial fusion protein (Opa1) levels in the mitochondrial fraction but increased reactive oxygen species formation, calpain and calcineurin activation, mitochondrial fission protein (Fis1 and Drp1) levels in the mitochondrial fraction and apoptotic cells. Nevertheless, these toxic effects were abolished in hydrogen peroxide-treated calpastatin-overexpressing SH-SY5Y cells. The results of the present study demonstrate the potential ability of calpastatin to diminish calpain and calcineurin activation and mitochondrial impairment in neurons that are affected by oxidative damage. PMID:27453331

  18. The mitochondrial inner membrane GTPase, optic atrophy 1 (Opa1), restores mitochondrial morphology and promotes neuronal survival following excitotoxicity.

    PubMed

    Jahani-Asl, Arezu; Pilon-Larose, Karine; Xu, William; MacLaurin, Jason G; Park, David S; McBride, Heidi M; Slack, Ruth S

    2011-02-11

    Mitochondrial dynamics have been extensively studied in the context of classical cell death models involving Bax-mediated cytochrome c release. Excitotoxic neuronal loss is a non-classical death signaling pathway that occurs following overactivation of glutamate receptors independent of Bax activation. Presently, the role of mitochondrial dynamics in the regulation of excitotoxicity remains largely unknown. Here, we report that NMDA-induced excitotoxicity results in defects in mitochondrial morphology as evident by the presence of excessive fragmented mitochondria, cessation of mitochondrial fusion, and cristae dilation. Up-regulation of the mitochondrial inner membrane GTPase, Opa1, is able to restore mitochondrial morphology and protect neurons against excitotoxic injury. Opa1 functions downstream of the calcium-dependent protease, calpain. Inhibition of calpain activity by calpastatin, an endogenous calpain inhibitor, significantly rescued mitochondrial defects and maintained neuronal survival. Opa1 was required for calpastatin-mediated neuroprotection because the enhanced survival found following NMDA-induced toxicity was significantly reduced upon loss of Opa1. Our results define a mechanism whereby breakdown of the mitochondrial network mediated through loss of Opa1 function contributes to neuronal death following excitotoxic neuronal injury. These studies suggest Opa1 as a potential therapeutic target to promote neuronal survival following acute brain damage and neurodegenerative diseases. PMID:21041314

  19. Negative regulation of mitochondrial transcription by mitochondrial topoisomerase I

    PubMed Central

    Sobek, Stefan; Dalla Rosa, Ilaria; Pommier, Yves; Bornholz, Beatrice; Kalfalah, Faiza; Zhang, Hongliang; Wiesner, Rudolf J.; von Kleist-Retzow, Jürgen-Christoph; Hillebrand, Frank; Schaal, Heiner; Mielke, Christian; Christensen, Morten O.; Boege, Fritz

    2013-01-01

    Mitochondrial topoisomerase I is a genetically distinct mitochondria-dedicated enzyme with a crucial but so far unknown role in the homeostasis of mitochondrial DNA metabolism. Here, we present data suggesting a negative regulatory function in mitochondrial transcription or transcript stability. Deficiency or depletion of mitochondrial topoisomerase I increased mitochondrial transcripts, whereas overexpression lowered mitochondrial transcripts, depleted respiratory complexes I, III and IV, decreased cell respiration and raised superoxide levels. Acute depletion of mitochondrial topoisomerase I triggered neither a nuclear mito-biogenic stress response nor compensatory topoisomerase IIβ upregulation, suggesting the concomitant increase in mitochondrial transcripts was due to release of a local inhibitory effect. Mitochondrial topoisomerase I was co-immunoprecipitated with mitochondrial RNA polymerase. It selectively accumulated and rapidly exchanged at a subset of nucleoids distinguished by the presence of newly synthesized RNA and/or mitochondrial RNA polymerase. The inactive Y559F-mutant behaved similarly without affecting mitochondrial transcripts. In conclusion, mitochondrial topoisomerase I dampens mitochondrial transcription and thereby alters respiratory capacity. The mechanism involves selective association of the active enzyme with transcriptionally active nucleoids and a direct interaction with mitochondrial RNA polymerase. The inhibitory role of topoisomerase I in mitochondrial transcription is strikingly different from the stimulatory role of topoisomerase I in nuclear transcription. PMID:23982517

  20. Status Epilepticus in Immature Rats Is Associated with Oxidative Stress and Mitochondrial Dysfunction.

    PubMed

    Folbergrová, Jaroslava; Ješina, Pavel; Kubová, Hana; Druga, Rastislav; Otáhal, Jakub

    2016-01-01

    Epilepsy is a neurologic disorder, particularly frequent in infants and children where it can lead to serious consequences later in life. Oxidative stress and mitochondrial dysfunction are implicated in the pathogenesis of many neurological disorders including epilepsy in adults. However, their role in immature epileptic brain is unclear since there have been two contrary opinions: oxidative stress is age-dependent and does not occur in immature brain during status epilepticus (SE) and, on the other hand, evidence of oxidative stress in immature brain during a specific model of SE. To solve this dilemma, we have decided to investigate oxidative stress following SE induced in immature 12-day-old rats by three substances with a different mechanism of action, namely 4-aminopyridine, LiCl-pilocarpine or kainic acid. Fluoro-Jade-B staining revealed mild brain damage especially in hippocampus and thalamus in each of the tested models. Decrease of glucose and glycogen with parallel rises of lactate clearly indicate high rate of glycolysis, which was apparently not sufficient in 4-AP and Li-Pilo status, as evident from the decreases of PCr levels. Hydroethidium method revealed significantly higher levels of superoxide anion (by ∼60%) in the hippocampus, cerebral cortex and thalamus of immature rats during status. SE lead to mitochondrial dysfunction with a specific pronounced decrease of complex I activity that persisted for a long period of survival. Complexes II and IV activities remained in the control range. Antioxidant treatment with SOD mimetic MnTMPYP or peroxynitrite scavenger FeTPPS significantly attenuated oxidative stress and inhibition of complex I activity. These findings bring evidence that oxidative stress and mitochondrial dysfunction are age and model independent, and may thus be considered a general phenomenon. They can have a clinical relevance for a novel approach to the treatment of epilepsy, allowing to target the mechanisms which play a crucial or

  1. Status Epilepticus in Immature Rats Is Associated with Oxidative Stress and Mitochondrial Dysfunction

    PubMed Central

    Folbergrová, Jaroslava; Ješina, Pavel; Kubová, Hana; Druga, Rastislav; Otáhal, Jakub

    2016-01-01

    Epilepsy is a neurologic disorder, particularly frequent in infants and children where it can lead to serious consequences later in life. Oxidative stress and mitochondrial dysfunction are implicated in the pathogenesis of many neurological disorders including epilepsy in adults. However, their role in immature epileptic brain is unclear since there have been two contrary opinions: oxidative stress is age-dependent and does not occur in immature brain during status epilepticus (SE) and, on the other hand, evidence of oxidative stress in immature brain during a specific model of SE. To solve this dilemma, we have decided to investigate oxidative stress following SE induced in immature 12-day-old rats by three substances with a different mechanism of action, namely 4-aminopyridine, LiCl-pilocarpine or kainic acid. Fluoro-Jade-B staining revealed mild brain damage especially in hippocampus and thalamus in each of the tested models. Decrease of glucose and glycogen with parallel rises of lactate clearly indicate high rate of glycolysis, which was apparently not sufficient in 4-AP and Li-Pilo status, as evident from the decreases of PCr levels. Hydroethidium method revealed significantly higher levels of superoxide anion (by ∼60%) in the hippocampus, cerebral cortex and thalamus of immature rats during status. SE lead to mitochondrial dysfunction with a specific pronounced decrease of complex I activity that persisted for a long period of survival. Complexes II and IV activities remained in the control range. Antioxidant treatment with SOD mimetic MnTMPYP or peroxynitrite scavenger FeTPPS significantly attenuated oxidative stress and inhibition of complex I activity. These findings bring evidence that oxidative stress and mitochondrial dysfunction are age and model independent, and may thus be considered a general phenomenon. They can have a clinical relevance for a novel approach to the treatment of epilepsy, allowing to target the mechanisms which play a crucial or

  2. S-Nitrosylation of Drp1 links excessive mitochondrial fission to neuronal injury in neurodegeneration

    PubMed Central

    Nakamura, Tomohiro; Cieplak, Piotr; Cho, Dong-Hyung; Godzik, Adam; Lipton, Stuart A.

    2010-01-01

    Neurons are known to use large amounts of energy for their normal function and activity. In order to meet this demand, mitochondrial fission, fusion, and movement events (mitochondrial dynamics) control mitochondrial morphology, facilitating biogenesis and proper distribution of mitochondria within neurons. In contrast, dysfunction in mitochondrial dynamics results in reduced cell bioenergetics and thus contributes to neuronal injury and death in many neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease, and Huntington’s disease. We recently reported that amyloid-β peptide, thought to be a key mediator of AD pathogenesis, engenders S-nitrosylation and thus hyperactivation of the mitochondrial fission protein Drp1. This activation leads to excessive mitochondrial fragmentation, bioenergetic compromise, and synaptic damage in models of AD. Here, we provide an extended commentary on our findings of nitric oxide-mediated abnormal mitochondrial dynamics. PMID:20447471

  3. S-nitrosylation of Drp1 links excessive mitochondrial fission to neuronal injury in neurodegeneration.

    PubMed

    Nakamura, Tomohiro; Cieplak, Piotr; Cho, Dong-Hyung; Godzik, Adam; Lipton, Stuart A

    2010-08-01

    Neurons are known to use large amounts of energy for their normal function and activity. In order to meet this demand, mitochondrial fission, fusion, and movement events (mitochondrial dynamics) control mitochondrial morphology, facilitating biogenesis and proper distribution of mitochondria within neurons. In contrast, dysfunction in mitochondrial dynamics results in reduced cell bioenergetics and thus contributes to neuronal injury and death in many neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease, and Huntington's disease. We recently reported that amyloid-beta peptide, thought to be a key mediator of AD pathogenesis, engenders S-nitrosylation and thus hyperactivation of the mitochondrial fission protein Drp1. This activation leads to excessive mitochondrial fragmentation, bioenergetic compromise, and synaptic damage in models of AD. Here, we provide an extended commentary on our findings of nitric oxide-mediated abnormal mitochondrial dynamics. PMID:20447471

  4. Mechanical overloading causes mitochondrial superoxide and SOD2 imbalance in chondrocytes resulting in cartilage degeneration.

    PubMed

    Koike, Masato; Nojiri, Hidetoshi; Ozawa, Yusuke; Watanabe, Kenji; Muramatsu, Yuta; Kaneko, Haruka; Morikawa, Daichi; Kobayashi, Keiji; Saita, Yoshitomo; Sasho, Takahisa; Shirasawa, Takuji; Yokote, Koutaro; Kaneko, Kazuo; Shimizu, Takahiko

    2015-01-01

    Mechanical stress and aging are major risk factors of cartilage degeneration. Human studies have previously reported that oxidative damage increased, while SOD2 protein was reciprocally downregulated in osteoarthritic degenerated cartilage. However, it remains unclear whether mitochondrial superoxide imbalance in chondrocytes causes cartilage degeneration. We herein demonstrate that mechanical loading promoted mitochondrial superoxide generation and selective Sod2 downregulation in chondrocytes in vivo and that mitochondrial superoxide inducer also downregulated Sod2 expression in chondrocytes in vitro. A genetically manipulated model revealed that Sod2 deficiency in chondrocytes also resulted in mitochondrial superoxide overproduction and dysfunction, thus leading to cartilage degeneration. Intra-articular injection of a permeable antioxidant effectively suppressed the mechanical loading-induced mitochondrial superoxide generation and cartilage degeneration in mice. Our findings demonstrate that mitochondrial superoxide plays a pivotal role in the development and progression of osteoarthritis, and the mitochondrial superoxide balance may therefore be a promising target for the treatment of cartilage degeneration. PMID:26108578

  5. Mechanical overloading causes mitochondrial superoxide and SOD2 imbalance in chondrocytes resulting in cartilage degeneration

    PubMed Central

    Koike, Masato; Nojiri, Hidetoshi; Ozawa, Yusuke; Watanabe, Kenji; Muramatsu, Yuta; Kaneko, Haruka; Morikawa, Daichi; Kobayashi, Keiji; Saita, Yoshitomo; Sasho, Takahisa; Shirasawa, Takuji; Yokote, Koutaro; Kaneko, Kazuo; Shimizu, Takahiko

    2015-01-01

    Mechanical stress and aging are major risk factors of cartilage degeneration. Human studies have previously reported that oxidative damage increased, while SOD2 protein was reciprocally downregulated in osteoarthritic degenerated cartilage. However, it remains unclear whether mitochondrial superoxide imbalance in chondrocytes causes cartilage degeneration. We herein demonstrate that mechanical loading promoted mitochondrial superoxide generation and selective Sod2 downregulation in chondrocytes in vivo and that mitochondrial superoxide inducer also downregulated Sod2 expression in chondrocytes in vitro. A genetically manipulated model revealed that Sod2 deficiency in chondrocytes also resulted in mitochondrial superoxide overproduction and dysfunction, thus leading to cartilage degeneration. Intra-articular injection of a permeable antioxidant effectively suppressed the mechanical loading-induced mitochondrial superoxide generation and cartilage degeneration in mice. Our findings demonstrate that mitochondrial superoxide plays a pivotal role in the development and progression of osteoarthritis, and the mitochondrial superoxide balance may therefore be a promising target for the treatment of cartilage degeneration. PMID:26108578

  6. 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. PMID:26816095

  7. Mitochondrial decay in the brains of old rats: ameliorating effect of alpha-lipoic acid and acetyl-L-carnitine.

    PubMed

    Long, Jiangang; Gao, Feng; Tong, Liqi; Cotman, Carl W; Ames, Bruce N; Liu, Jiankang

    2009-04-01

    To investigate the mitochondrial decay and oxidative damage resulting from aging, the activities/kinetics of the mitochondrial complexes were examined in the brains of young and old rats as well as in old rats fed R-alpha-lipoic acid plus acetyl-L-carnitine (LA/ALC). The brain mitochondria of old rats, compared with young rats, had significantly decreased endogenous antioxidants and superoxide dismutase activity; more oxidative damage to lipids and proteins; and decreased activities of complex I, IV and V. Complex I showed a decrease in binding affinity (increase in K(m)) for substrates. Feeding LA/ALC to old rats partially restored age-associated mitochondrial dysfunction to the levels of the young rats. These results indicate that oxidative mitochondrial decay plays an important role in brain aging and that a combination of nutrients targeting mitochondria, such as LA/ALC, could ameliorate mitochondrial decay through preventing mitochondrial oxidative damage. PMID:18846423

  8. Mitochondrial Decay in the Brains of Old Rats: Ameliorating Effect of Alpha-Lipoic Acid and Acetyl-L-carnitine

    PubMed Central

    Long, Jiangang; Gao, Feng; Tong, Liqi; Cotman, Carl W.; Ames, Bruce N.

    2009-01-01

    To investigate the mitochondrial decay and oxidative damage resulting from aging, the activities/kinetics of the mitochondrial complexes were examined in the brains of young and old rats as well as in old rats fed R-α-lipoic acid plus acetyl-L-carnitine (LA/ALC). The brain mitochondria of old rats, compared with young rats, had significantly decreased endogenous antioxidants and superoxide dismutase activity; more oxidative damage to lipids and proteins; and decreased activities of complex I, IV and V. Complex I showed a decrease in binding affinity (increase in Km) for substrates. Feeding LA/ALC to old rats partially restored age-associated mitochondrial dysfunction to the levels of the young rats. These results indicate that oxidative mitochondrial decay plays an important role in brain aging and that a combination of nutrients targeting mitochondria, such as LA/ALC, could ameliorate mitochondrial decay through preventing mitochondrial oxidative damage. PMID:18846423

  9. Treatment of Mitochondrial Disorders

    PubMed Central

    Avula, Sreenivas; Parikh, Sumit; Demarest, Scott; Kurz, Jonathan; Gropman, Andrea

    2014-01-01

    Opinion statement While numerous treatments for mitochondrial disorders have been suggested, relatively few have undergone controlled clinical trials. Treatment of these disorders is challenging, as only symptomatic therapy is available. In this review we will focus on newer drugs and treatment trials in mitochondrial diseases, with a special focus on medications to avoid in treating epilepsy and ICU patient with mitochondrial disease, which has not been included in such a review. Readers are also referred to the opinion statement in A Modern Approach to the Treatment of Mitochondrial Disease published in Current Treatment Options in Neurology 2009. Many of the supplements used for treatment were reviewed in the previous abstract, and dosing guidelines were provided. The focus of this review is on items not previously covered in depth, and our discussion includes more recently studied compounds as well as any relevant updates on older compounds. We review a variety of vitamins and xenobiotics, including dichloroacetate (DCA), arginine, coenzyme Q10, idebenone, EPI-743, and exercise training. Treatment of epilepsy, which is a common feature in many mitochondrial phenotypes, warrants special consideration due to the added toxicity of certain medications, and we provide a discussion of these unique treatment challenges. Interesting, however, with only a few exceptions, the treatment strategies for epilepsy in mitochondrial cytopathies are the same as for epilepsy without mitochondrial dysfunction. We also discuss intensive care management, building upon similar reviews, adding new dimensions, and demonstrating the complexity of overall care of these patients. PMID:24700433

  10. Persistent depressive disorder

    MedlinePlus

    PDD; Chronic depression; Depression - chronic ... The exact cause of persistent depressive disorder (PDD) is unknown. It tends to run in families. PDD occurs more often in women. Most people with PDD will also ...

  11. Persistent depressive disorder

    MedlinePlus

    The exact cause of persistent depressive disorder (PDD) is unknown. It tends to run in families. PDD occurs more often in women. Most people with PDD will also have an episode of major depression at some point in their lives. ...

  12. Persistent heap Management library

    Energy Science and Technology Software Center (ESTSC)

    2012-01-17

    PERM is a C library for persistent heap management and is intended for use with a dynamic-memory allocator (e.g. malloc, free). The PERM memory allocator replaces the standard C dynamic memory allocation functions with compatible versions that provide persistent memory to application programs. Memory allocated with the PERM allocatory will persist between program invocations after a call to a checkpoint function. This function essentially saves the state of the heap and registered global variables tomore » a file which may reside in flash memory or other node local storage. A few other functions are also provided by the library to manage checkpoint files. Global variables in an application can be marked persistent and be included in a checkpoint by using a compiler attribute defined as PERM. The PERM checkpoint methof is not dependent on the programming model ans works with distributed memory or shared memory programs.« less

  13. Persistent heap Management library

    SciTech Connect

    2012-01-17

    PERM is a C library for persistent heap management and is intended for use with a dynamic-memory allocator (e.g. malloc, free). The PERM memory allocator replaces the standard C dynamic memory allocation functions with compatible versions that provide persistent memory to application programs. Memory allocated with the PERM allocatory will persist between program invocations after a call to a checkpoint function. This function essentially saves the state of the heap and registered global variables to a file which may reside in flash memory or other node local storage. A few other functions are also provided by the library to manage checkpoint files. Global variables in an application can be marked persistent and be included in a checkpoint by using a compiler attribute defined as PERM. The PERM checkpoint methof is not dependent on the programming model ans works with distributed memory or shared memory programs.

  14. [Persistent idiopathic facial pain and atypical odontalgia].

    PubMed

    Gaul, Charly; Ettlin, Dominik; Pfau, Doreen B

    2013-01-01

    The terms 'persistent idiopathic facial pain' (PIFP) and 'atypical odontalgia' (AO) are currently used as exclusion diagnoses for chronic toothache and chronic facial pain. Knowledge about these pain conditions in medical and dental practices is of crucial importance for the prevention of iatrogenic tissue damage by not-indicated invasive interventions, such as endodontic treatment and tooth extraction. In the present paper, etiology and pathogenesis, differential diagnostic criteria, and diagnostic approaches will be explained and relevant therapeutic principles will be outlined. PMID:23916270

  15. Free radicals and tissue damage produced by exercise

    SciTech Connect

    Davies, K.J.A.; Quintanilha, A.T.; Brooks, G.A; Packer, L.

    1982-08-31

    Reported is a two- to three-fold increase in free radical (R*) concentrations of muscle and liver following exercise to exhaustion. Exhaustive exercise also resulted in decreased mitochondrial respiratory control, loss of sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) integrity, and increased levels of lipid peroxidation products. Free radical concentrations, lipid peroxidation, and SR, ER, and mitochondrial damage were similar in exercise exhausted control animals and non-exercised vitamin E deficient animals, suggesting the possibility of a common R* dependent damage process. In agreement with previous work showing that exercise endurance capacity is largely determined by the functional mitochondrial content of muscle, vitamin E deficient animals endurance was 40% lower than that of controls. The results suggest that R* induced damage may provide a stimulus to the mitochondrial biogenesis which results from endurance training.

  16. Mitochondrial diseases and epilepsy.

    PubMed

    Bindoff, Laurence A; Engelsen, Bernt A

    2012-09-01

    The mitochondrial respiratory chain is the final common pathway for energy production. Defects affecting this pathway can give rise to disease that presents at any age and affects any tissue. However, irrespective of genetic defect, epilepsy is common and there is a significant risk of status epilepticus. This review summarizes our current understanding of the epilepsy that occurs in mitochondrial disease, focusing on three of the most common disorders: mitochondrial myopathy encephalopathy, lactic acidosis and stroke-like episodes (MELAS), myoclonus epilepsy and ragged-red fibers (MERRF), and polymerase gamma (POLG) related disease. In addition, we review the pathogenesis and possible treatment of these disorders. PMID:22946726

  17. Arsenic trioxide (As(2)O(3)) induces apoptosis and necrosis mediated cell death through mitochondrial membrane potential damage and elevated production of reactive oxygen species in PLHC-1 fish cell line.

    PubMed

    Selvaraj, Vellaisamy; Armistead, Mindy Yeager; Cohenford, Menashi; Murray, Elizabeth

    2013-01-01

    Several environmental pollutants, including metals can induce toxicological effect on aquatic animal species. Most studies to understand the toxicity of arsenic compounds were performed in mammalian cells; however, the study of the arsenic toxicity to the aquatic animals' species, including fish, is limited. So the objective of this study was first to investigate the effects of As(2)O(3) induced toxicity particularly on apoptosis and necrosis mediated cell death in fish cell PLHC-1 as compared to the mechanism of toxicity from known mammalian cell lines, secondly to relate in vitro effects in fish to those demonstrated by in vivo systems. To conduct this study, PLHC-1 cells were exposed to various concentrations of As(2)O(3) (0-100 μM) for 10, 20 and 40 h. The results indicate that As(2)O(3) exposure promoted apoptotic and necrotic mediated cell death in a concentration and time dependent manner. Cell death (apoptotic and necrotic) induced by As(2)O(3) was further confirmed by changes in various phases of cell cycle, DNA fragmentation (necro- comet and apo-comet) in the comet assay, alteration in mitochondrial membrane potential and formation of increased reactive oxygen species (ROS). Apoptotic mediated cell death was confirmed further by observing the increased caspase-3 activity and elevated expression of p53, cytochrome c and Bax proteins levels in the same experimental conditions. PLHC-1 cells were shown to be a good model for evaluating biochemical/cytotoxic effects following exposure to various reference chemicals and environmental contaminants. In vitro data obtained from this study provides a comprehensive approach for the elucidating the actual molecular mechanism for As(2)O(3) induced toxicity particularly apoptosis and necrosis mediated cell death in PLHC-1 cell line. PMID:23121984

  18. Short Mitochondrial ARF Triggers Parkin/PINK1-dependent Mitophagy*

    PubMed Central

    Grenier, Karl; Kontogiannea, Maria; Fon, Edward A.

    2014-01-01

    Parkinson disease (PD) is a complex neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra. Multiple genes have been associated with PD, including Parkin and PINK1. Recent studies have established that the Parkin and PINK1 proteins function in a common mitochondrial quality control pathway, whereby disruption of the mitochondrial membrane potential leads to PINK1 stabilization at the mitochondrial outer surface. PINK1 accumulation leads to Parkin recruitment from the cytosol, which in turn promotes the degradation of the damaged mitochondria by autophagy (mitophagy). Most studies characterizing PINK1/Parkin mitophagy have relied on high concentrations of chemical uncouplers to trigger mitochondrial depolarization, a stimulus that has been difficult to adapt to neuronal systems and one unlikely to faithfully model the mitochondrial damage that occurs in PD. Here, we report that the short mitochondrial isoform of ARF (smARF), previously identified as an alternate translation product of the tumor suppressor p19ARF, depolarizes mitochondria and promotes mitophagy in a Parkin/PINK1-dependent manner, both in cell lines and in neurons. The work positions smARF upstream of PINK1 and Parkin and demonstrates that mitophagy can be triggered by intrinsic signaling cascades. PMID:25217637

  19. MITOCHONDRIAL GLUTATHIONE: FEATURES, REGULATION AND ROLE IN DISEASE

    PubMed Central

    Marí, Montserrat; Morales, Albert; Colell, Anna; García-Ruiz, Carmen; Kaplowitz, Neil; Fernández-Checa, José C

    2012-01-01

    BACKGROUND Mitochondria are the powerhouse of mammalian cells and the main source of reactive oxygen species (ROS) associated with oxygen consumption. In addition, they also play a strategic role in controlling the fate of cells through regulation of death pathways. Mitochondrial ROS production fulfills a signaling role through regulation of redox pathways, but also contributes to mitochondrial damage in a number of pathological states. SCOPE OF REVIEW Mitochondria are exposed to the constant generation of oxidant species, and yet the organelle remains functional due to the existence of an armamentarium of antioxidant defense systems aimed to repair oxidative damage, of which mitochondrial glutathione (mGSH) is of particular relevance. Thus, the aim of the review is to cover the regulation of mGSH and its role in disease. MAJOR CONCLUSIONS Cumulating evidence over recent years has demonstrated the essential role for mGSH in mitochondrial physiology and disease. Despite its high concentration in the mitochondrial matrix, mitochondria lack the enzymes to synthesize GSH de novo, so that mGSH originates from cytosolic GSH via transport through specific mitochondrial carriers, which exhibit sensitivity to membrane dynamics. Depletion of mGSH sensitizes cells to stimuli leading to oxidative stress such as TNF, hypoxia or amyloid β-peptide, thereby contributing to disease pathogenesis. GENERAL SIGNIFICANCE Understanding the regulation of mGSH may provide novel insights to disease pathogenesis and toxicity and the opportunity to design therapeutic targets of intervention in cell death susceptibility and disease. PMID:23123815

  20. The HIV Protein gp120 Alters Mitochondrial Dynamics in Neurons.

    PubMed

    Avdoshina, Valeria; Fields, Jerel Adam; Castellano, Paul; Dedoni, Simona; Palchik, Guillermo; Trejo, Margarita; Adame, Anthony; Rockenstein, Edward; Eugenin, Eliseo; Masliah, Eliezer; Mocchetti, Italo

    2016-05-01

    Neurotoxicity of human immunodeficiency virus-1 (HIV) includes synaptic simplification and neuronal apoptosis. However, the mechanisms of HIV-associated neurotoxicity remain unclear, thus precluding an effective treatment of the neurological complications. The present study was undertaken to characterize novel mechanisms of HIV neurotoxicity that may explain how HIV subjects develop neuronal degeneration. Several neurodegenerative disorders are characterized by mitochondrial dysfunction; therefore, we hypothesized that HIV promotes mitochondrial damage. We first analyzed brains from HIV encephalitis (HIVE) by electron microscopy. Several sections of HIVE subjects contained enlarged and damaged mitochondria compared to brains from HIV subjects with no neurological complications. Similar pathologies were observed in mice overexpressing the HIV protein gp120, suggesting that this viral protein may be responsible for mitochondrial pathology found in HIVE. To gain more information about the cellular mechanisms of gp120 neurotoxicity, we exposed rat cortical neurons to gp120 and we determined cellular oxygen consumption rate, mitochondrial distribution, and trafficking. Our data show that gp120 evokes impairment in mitochondrial function and distribution. These data suggest that one of the mechanisms of HIV neurotoxicity includes altered mitochondrial dynamics in neurons. PMID:26936603

  1. Mitochondrial biogenesis: pharmacological approaches.

    PubMed

    Valero, Teresa

    2014-01-01

    Organelle biogenesis is concomitant to organelle inheritance during cell division. It is necessary that organelles double their size and divide to give rise to two identical daughter cells. Mitochondrial biogenesis occurs by growth and division of pre-existing organelles and is temporally coordinated with cell cycle events [1]. However, mitochondrial biogenesis is not only produced in association with cell division. It can be produced in response to an oxidative stimulus, to an increase in the energy requirements of the cells, to exercise training, to electrical stimulation, to hormones, during development, in certain mitochondrial diseases, etc. [2]. Mitochondrial biogenesis is therefore defined as the process via which cells increase their individual mitochondrial mass [3]. Recent discoveries have raised attention to mitochondrial biogenesis as a potential target to treat diseases which up to date do not have an efficient cure. Mitochondria, as the major ROS producer and the major antioxidant producer exert a crucial role within the cell mediating processes such as apoptosis, detoxification, Ca2+ buffering, etc. This pivotal role makes mitochondria a potential target to treat a great variety of diseases. Mitochondrial biogenesis can be pharmacologically manipulated. This issue tries to cover a number of approaches to treat several diseases through triggering mitochondrial biogenesis. It contains recent discoveries in this novel field, focusing on advanced mitochondrial therapies to chronic and degenerative diseases, mitochondrial diseases, lifespan extension, mitohormesis, intracellular signaling, new pharmacological targets and natural therapies. It contributes to the field by covering and gathering the scarcely reported pharmacological approaches in the novel and promising field of mitochondrial biogenesis. There are several diseases that have a mitochondrial origin such as chronic progressive external ophthalmoplegia (CPEO) and the Kearns- Sayre syndrome (KSS

  2. Mitochondrial DNA mutations and breast tumorigenesis

    PubMed Central

    Yadav, Neelu; Chandra, Dhyan

    2013-01-01

    Breast cancer is a heterogeneous disease and genetic factors play an important role in its genesis. Although mutations in tumor suppressors and oncogenes encoded by the nuclear genome are known to play a critical role in breast tumorigenesis, the contribution of the mitochondrial genome to this process is unclear. Like the nuclear genome, the mitochondrial genome also encodes proteins critical for mitochondria functions such as oxidative phosphorylation (OXPHOS), which is known to be defective in cancer including breast cancer. Due to limited repair mechanisms compared to that for nuclear DNA (nDNA), mitochondrial DNA (mtDNA) is more susceptible to mutations. Thus changes in mitochondrial genes could also contribute to the development of breast cancer. In this review we discuss mtDNA mutations that affect OXPHOS. Continuous acquisition of mtDNA mutations and selection of advantageous mutations ultimately leads to generation of cells that propagate uncontrollably to form tumors. Since irreversible damage to OXPHOS leads to a shift in energy metabolism towards enhanced aerobic glycolysis in most cancers, mutations in mtDNA represent an early event during breast tumorigenesis, and thus may serve as potential biomarkers for early detection and prognosis of breast cancer. Because mtDNA mutations lead to defective OXPHOS, development of agents that target OXPHOS will provide specificity for preventative and therapeutic agents against breast cancer with minimal toxicity. PMID:24140413

  3. The ageing neuromuscular system and sarcopenia: a mitochondrial perspective.

    PubMed

    Rygiel, Karolina A; Picard, Martin; Turnbull, Doug M

    2016-08-15

    Skeletal muscles undergo structural and functional decline with ageing, culminating in sarcopenia. The underlying neuromuscular mechanisms have been the subject of intense investigation, revealing mitochondrial abnormalities as potential culprits within both nerve and muscle cells. Implicated mechanisms involve impaired mitochondrial dynamics, reduced organelle biogenesis and quality control via mitophagy, accumulation of mitochondrial DNA (mtDNA) damage and respiratory chain defect, metabolic disturbance, pro-apoptotic signalling, and oxidative stress. This article provides an overview of the cellular mechanisms whereby mitochondria may promote maladaptive changes within motor neurons, the neuromuscular junction (NMJ) and muscle fibres. Lifelong physical activity, which promotes mitochondrial health across tissues, is emerging as an effective countermeasure for sarcopenia. PMID:26921061

  4. Mitochondrial dynamics and quality control in Huntington's disease.

    PubMed

    Guedes-Dias, Pedro; Pinho, Brígida R; Soares, Tânia R; de Proença, João; Duchen, Michael R; Oliveira, Jorge M A

    2016-06-01

    Huntington's disease (HD) is an inherited neurodegenerative disorder caused by polyglutamine expansion mutations in the huntingtin protein. Despite its ubiquitous distribution, expression of mutant huntingtin (mHtt) is particularly detrimental to medium spiny neurons within the striatum. Mitochondrial dysfunction has been associated with HD pathogenesis. Here we review the current evidence for mHtt-induced abnormalities in mitochondrial dynamics and quality control, with a particular focus on brain and neuronal data pertaining to striatal vulnerability. We address mHtt effects on mitochondrial biogenesis, protein import, complex assembly, fission and fusion, mitochondrial transport, and on the degradation of damaged mitochondria via autophagy (mitophagy). For an integrated perspective on potentially converging pathogenic mechanisms, we also address impaired autophagosomal transport and abnormal mHtt proteostasis in HD. PMID:26388396

  5. Dysfunction of Rice Mitochondrial Membrane Induced by Yb3+.

    PubMed

    Gao, Jia-Ling; Wu, Man; Liu, Wen; Feng, Zhi-Jiang; Zhang, Ye-Zhong; Jiang, Feng-Lei; Liu, Yi; Dai, Jie

    2015-12-01

    Ytterbium (Yb), a widely used rare earth element, is treated as highly toxic to human being and adverseness to plant. Mitochondria play a significant role in plant growth and development, and are proposed as a potential target for ytterbium toxicity. In this paper, the biological effect of Yb(3+) on isolated rice mitochondria was investigated. We found that Yb(3+) with high concentrations (200 ~ 600 μM) not only induced mitochondrial membrane permeability transition (mtMPT), but also disturbed the mitochondrial ultrastructure. Moreover, Yb(3+) caused the respiratory chain damage, ROS formation, membrane potential decrease, and mitochondrial complex II activity reverse. The results above suggested that Yb(3+) with high concentrations could induce mitochondrial membrane dysfunction. These findings will support some valuable information to the safe application of Yb-based agents. PMID:26305923

  6. Mitochondrial dysfunction contributes to neurodegeneration in multiple sclerosis.

    PubMed

    Witte, Maarten E; Mahad, Don J; Lassmann, Hans; van Horssen, Jack

    2014-03-01

    Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Current treatments are very effective in reducing the neuroinflammatory attack, but fail to significantly halt disease progression and associated loss of neuronal tissue. In recent years, it has become increasingly clear that dysfunctional mitochondria are important contributors to damage and loss of both axons and neurons. Observations in animal and histopathological studies suggest that infiltrating leukocytes and activated microglia play a central role in neuronal mitochondrial dysfunction. This review provides a comprehensive overview on the current knowledge regarding mitochondrial dysfunction in MS. Importantly, more insight into the cause and consequences of impaired mitochondrial function provide a basis for mitochondrial-targeted medicine to combat progressive MS. PMID:24369898

  7. Mitochondrial dynamics: Orchestrating the journey to advanced age.

    PubMed

    Biala, Agnieszka K; Dhingra, Rimpy; Kirshenbaum, Lorrie A

    2015-06-01

    Aging is a degenerative process that unfortunately is an inevitable part of life and risk factor for cardiovascular disease including heart failure. Among the several theories purported to explain the effects of age on cardiac dysfunction, the mitochondrion has emerged a central regulator of this process. Hence, it is not surprising that abnormalities in mitochondrial quality control including biogenesis and turnover have such detrimental effects on cardiac function. In fact mitochondria serve as a conduit for biological signals for apoptosis, necrosis and autophagy respectively. The removal of damaged mitochondria by autophagy/mitophagy is essential for mitochondrial quality control and cardiac homeostasis. Defects in mitochondrial dynamism fission/fusion events have been linked to cardiac senescence and heart failure. In this review we discuss the impact of aging on mitochondrial dynamics and senescence on cardiovascular health. This article is part of a Special Issue entitled: CV Aging. PMID:25918048

  8. 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.; Agarwal, Anupam; 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

  9. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    PubMed Central

    Martin, Lee J.

    2010-01-01

    Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS) are the most common human adult-onset neurodegenerative diseases. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of AD, PD, and ALS are inherited, and genes causing these diseases have been identified. Nevertheless, the mechanisms of the neuronal cell death are unresolved. Morphological, biochemical, genetic, as well as cell and animal model studies reveal that mitochondria could have roles in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations, triggering neurodegeneration according to a cell death matrix theory. In AD, alterations in enzymes involved in oxidative phosphorylation, oxidative damage, and mitochondrial binding of Aβ and amyloid precursor protein have been reported. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review summarizes how mitochondrial pathobiology might contribute to neuronal death in AD, PD, and ALS and could serve as a target for drug therapy. PMID:21258649

  10. Experimental treatments for mitochondrial dysfunction in sepsis: A narrative review

    PubMed Central

    Zheng, Guilang; Lyu, Juanjuan; Huang, Jingda; Xiang, Dan; Xie, Meiyan; Zeng, Qiyi

    2015-01-01

    Sepsis is a systemic inflammatory response to infection. Sepsis, which can lead to severe sepsis, septic shock, and multiple organ dysfunction syndrome, is an important cause of mortality. Pathogenesis is extremely complex. In recent years, cell hypoxia caused by mitochondrial dysfunction has become a hot research field. Sepsis damages the structure and function of mitochondria, conversely, mitochondrial dysfunction aggravated sepsis. The treatment of sepsis lacks effective specific drugs. The aim of this paper is to undertake a narrative review of the current experimental treatment for mitochondrial dysfunction in sepsis. The search was conducted in PubMed databases and Web of Science databases from 1950 to January 2014. A total of 1,090 references were retrieved by the search, of which 121 researches met all the inclusion criteria were included. Articles on the relationship between sepsis and mitochondria, and drugs used for mitochondrial dysfunction in sepsis were reviewed retrospectively. The drugs were divided into four categories: (1) Drug related to mitochondrial matrix and respiratory chain, (2) drugs of mitochondrial antioxidant and free radical scavengers, (3) drugs related to mitochondrial membrane stability, (4) hormone therapy for septic mitochondria. In animal experiments, many drugs show good results. However, clinical research lacks. In future studies, the urgent need is to develop promising drugs in clinical trials. PMID:25983774

  11. Defective mitochondrial fission augments NLRP3 inflammasome activation.

    PubMed

    Park, Sangjun; Won, Ji-Hee; Hwang, Inhwa; Hong, Sujeong; Lee, Heung Kyu; Yu, Je-Wook

    2015-01-01

    Despite the fact that deregulated NLRP3 inflammasome activation contributes to the pathogenesis of chronic inflammatory or metabolic disorders, the underlying mechanism by which NLRP3 inflammasome signaling is initiated or potentiated remains poorly understood. Much attention is being paid to mitochondria as a regulator of NLRP3 inflammasome activation, but little is known about the role of mitochondrial dynamics for the inflammasome pathway. Here, we present evidence that aberrant mitochondrial elongation caused by the knockdown of dynamin-related protein 1 (Drp1) lead to a marked increase in NLRP3-dependent caspase-1 activation and interleukin-1-beta secretion in mouse bone marrow-derived macrophages. Conversely, carbonyl cyanide m-chlorophenyl hydrazone, a chemical inducer of mitochondrial fission, clearly attenuated NLRP3 inflammasome assembly and activation. Augmented activation of NLRP3 inflammasome by mitochondrial elongation is not resulted from the increased mitochondrial damages of Drp1-knockdown cells. Notably, enhanced extracellular signal-regulated kinase (ERK) signaling in Drp1-knockdown macrophages is implicated in the potentiation of NLRP3 inflammasome activation, possibly via mediating mitochondrial localization of NLRP3 to facilitate the assembly of NLRP3 inflammasome. Taken together, our results provide a molecular insight into the importance of mitochondrial dynamics in potentiating NLRP3 inflammasome activation, leading to aberrant inflammation. PMID:26489382

  12. Inherited mitochondrial neuropathies.

    PubMed

    Finsterer, Josef

    2011-05-15

    Mitochondrial disorders (MIDs) occasionally manifest as polyneuropathy either as the dominant feature or as one of many other manifestations (inherited mitochondrial neuropathy). MIDs in which polyneuropathy is the dominant feature, include NARP syndrome due to the transition m.8993T>, CMT2A due to MFN2 mutations, CMT2K and CMT4A due to GDAP1 mutations, and axonal/demyelinating neuropathy with external ophthalmoplegia due to POLG1 mutations. MIDs in which polyneuropathy is an inconstant feature among others is the MELAS syndrome, MERRF syndrome, LHON, Mendelian PEO, KSS, Leigh syndrome, MNGIE, SANDO; MIRAS, MEMSA, AHS, MDS (hepato-cerebral form), IOSCA, and ADOA syndrome. In the majority of the cases polyneuropathy presents in a multiplex neuropathy distribution. Nerve conduction studies may reveal either axonal or demyelinated or mixed types of neuropathies. If a hereditary neuropathy is due to mitochondrial dysfunction, the management of these patients is at variance from non-mitochondrial hereditary neuropathies. Patients with mitochondrial hereditary neuropathy need to be carefully investigated for clinical or subclinical involvement of other organs or systems. Supportive treatment with co-factors, antioxidants, alternative energy sources, or lactate lowering agents can be tried. Involvement of other organs may require specific treatment. Mitochondrial neuropathies should be included in the differential diagnosis of hereditary neuropathies. PMID:21402391

  13. Dynamin-related protein 1 and mitochondrial fragmentation in neurodegenerative diseases.

    PubMed

    Reddy, P Hemachandra; Reddy, Tejaswini P; Manczak, Maria; Calkins, Marcus J; Shirendeb, Ulziibat; Mao, Peizhong

    2011-06-24

    The purpose of this article is to review the recent developments of abnormal mitochondrial dynamics, mitochondrial fragmentation, and neuronal damage in neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis. The GTPase family of proteins, including fission proteins, dynamin related protein 1 (Drp1), mitochondrial fission 1 (Fis1), and fusion proteins (Mfn1, Mfn2 and Opa1) are essential to maintain mitochondrial fission and fusion balance, and to provide necessary adenosine triphosphate to neurons. Among these, Drp1 is involved in several important aspects of mitochondria, including shape, size, distribution, remodeling, and maintenance of mitochondria in mammalian cells. In addition, recent advancements in molecular, cellular, electron microscopy, and confocal imaging studies revealed that Drp1 is associated with several cellular functions, including mitochondrial and peroxisomal fragmentation, phosphorylation, SUMOylation, ubiquitination, and cell death. In the last two decades, tremendous progress has been made in researching mitochondrial dynamics, in yeast, worms, and mammalian cells; and this research has provided evidence linking Drp1 to neurodegenerative diseases. Researchers in the neurodegenerative disease field are beginning to recognize the possible involvement of Drp1 in causing mitochondrial fragmentation and abnormal mitochondrial dynamics in neurodegenerative diseases. This article summarizes research findings relating Drp1 to mitochondrial fission and fusion, in yeast, worms, and mammals. Based on findings from the Reddy laboratory and others', we propose that mutant proteins of neurodegenerative diseases, including AD, PD, HD, and ALS, interact with Drp1, activate mitochondrial fission machinery, fragment mitochondria excessively, and impair mitochondrial transport and mitochondrial dynamics, ultimately causing mitochondrial dysfunction and neuronal damage. PMID:21145355

  14. Antioxidant treatment reverses mitochondrial dysfunction in a sepsis animal model.

    PubMed

    Zapelini, Paula H; Rezin, Gislaine T; Cardoso, Mariane R; Ritter, Cristiane; Klamt, Fábio; Moreira, José C F; Streck, Emilio L; Dal-Pizzol, Felipe

    2008-06-01

    Evidence from the literature has demonstrated that reactive oxygen species (ROS) play an important role in the development of multiple organ failure and septic shock. In addition, mitochondrial dysfunction has been implicated in the pathogenesis of multiple organ dysfunction syndrome (MODS). The hypothesis of cytopathic hypoxia postulates that impairment in mitochondrial oxidative phosphorylation reduces aerobic adenosine triphosphate (ATP) production and potentially induces MODS. In this work, our aim was to evaluate the effects of antioxidants on oxidative damage and energy metabolism parameters in liver of rats submitted to a cecal ligation puncture (CLP) model of sepsis. We speculate that CLP induces a sequence of events that culminate with liver cells death. We propose that mitochondrial superoxide production induces mitochondrial oxidative damage, leading to mitochondrial dysfunction, swelling and release of cytochrome c. These events occur in early sepsis development, as reported in the present work. Liver cells necrosis only occurs 24 h after CLP, but all other events occur earlier (6-12 h). Moreover, we showed that antioxidants may prevent oxidative damage and mitochondrial dysfunction in liver of rats after CLP. In another set of experiments, we verified that L-NAME administration did not reverse increase of superoxide anion production, TBARS formation, protein carbonylation, mitochondrial swelling, increased serum AST or inhibition on complex IV activity caused by CLP. Considering that this drug inhibits nitric oxide synthase and that no parameter was reversed by its administration, we suggest that all the events reported in this study are not mediated by nitric oxide. In conclusion, although it is difficult to extrapolate our findings to human, it is tempting to speculate that antioxidants may be used in the future in the treatment of this disease. PMID:18417427

  15. Mitochondrial Ryanodine Receptors and Other Mitochondrial Ca2+ Permeable Channels

    PubMed Central

    Ryu, Shin-Young; Beutner, Gisela; Dirksen, Robert T.; Kinnally, Kathleen W.; Sheu, Shey-Shing

    2010-01-01

    Ca2+ channels that underlie mitochondrial Ca2+ transport first reported decades ago have now just recently been precisely characterized electrophysiologically. Numerous data indicate that mitochondrial Ca2+ uptake via these channels regulates multiple intracellular processes by shaping cytosolic and mitochondrial Ca2+ transients, as well as altering the cellular metabolic and redox state. On the other hand, mitochondrial Ca2+ overload also initiates a cascade of events that leads to cell death. Thus, characterization of mitochondrial Ca2+ channels is central to a comprehensive understanding of cell signaling. Here, we discuss recent progresses in the biophysical and electrophysiological characterization of several distinct mitochondrial Ca2+ channels. PMID:20096690

  16. Oxygen Reperfusion Damage in an Insect

    PubMed Central

    Lighton, John R. B.; Schilman, Pablo E.

    2007-01-01

    The deleterious effects of anoxia followed by reperfusion with oxygen in higher animals including mammals are well known. A convenient and genetically well characterized small-animal model that exhibits reproducible, quantifiable oxygen reperfusion damage is currently lacking. Here we describe the dynamics of whole-organism metabolic recovery from anoxia in an insect, Drosophila melanogaster, and report that damage caused by oxygen reperfusion can be quantified in a novel but straightforward way. We monitored CO2 emission (an index of mitochondrial activity) and water vapor output (an index of neuromuscular control of the spiracles, which are valves between the outside air and the insect's tracheal system) during entry into, and recovery from, rapid-onset anoxia exposure with durations ranging from 7.5 to 120 minutes. Anoxia caused a brief peak of CO2 output followed by knock-out. Mitochondrial respiration ceased and the spiracle constrictor muscles relaxed, but then re-contracted, presumably powered by anaerobic processes. Reperfusion to sustained normoxia caused a bimodal re-activation of mitochondrial respiration, and in the case of the spiracle constrictor muscles, slow inactivation followed by re-activation. After long anoxia durations, both the bimodality of mitochondrial reactivation and the recovery of spiracular control were impaired. Repeated reperfusion followed by episodes of anoxia depressed mitochondrial respiratory flux rates and damaged the integrity of the spiracular control system in a dose-dependent fashion. This is the first time that physiological evidence of oxygen reperfusion damage has been described in an insect or any invertebrate. We suggest that some of the traditional approaches of insect respiratory biology, such as quantifying respiratory water loss, may facilitate using D. melanogaster as a convenient, well-characterized experimental model for studying the underlying biology and mechanisms of ischemia and reperfusion damage and its

  17. Low-dose ionizing radiation induces mitochondrial fusion and increases expression of mitochondrial complexes I and III in hippocampal neurons

    PubMed Central

    Chang, Chuang-Rung; Kao, Mou-Chieh; Chen, Kuan-Wei; Chiu, Shih-Che; Hsu, Ming-Ling; Hsiang, I-Chou; Chen, Yu-Jen; Chen, Linyi

    2015-01-01

    High energy ionizing radiation can cause DNA damage and cell death. During clinical radiation therapy, the radiation dose could range from 15 to 60 Gy depending on targets. While 2 Gy radiation has been shown to cause cancer cell death, studies also suggest a protective potential by low dose radiation. In this study, we examined the effect of 0.2-2 Gy radiation on hippocampal neurons. Low dose 0.2 Gy radiation treatment increased the levels of MTT. Since hippocampal neurons are post-mitotic, this result reveals a possibility that 0.2 Gy irradiation may increase mitochondrial activity to cope with stimuli. Maintaining neural plasticity is an energy-demanding process that requires high efficient mitochondrial function. We thus hypothesized that low dose radiation may regulate mitochondrial dynamics and function to ensure survival of neurons. Our results showed that five days after 0.2 Gy irradiation, no obvious changes on neuronal survival, neuronal synapses, membrane potential of mitochondria, reactive oxygen species levels, and mitochondrial DNA copy numbers. Interestingly, 0.2 Gy irradiation promoted the mitochondria fusion, resulting in part from the increased level of a mitochondrial fusion protein, Mfn2, and inhibition of Drp1 fission protein trafficking to the mitochondria. Accompanying with the increased mitochondrial fusion, the expressions of complexes I and III of the electron transport chain were also increased. These findings suggest that, hippocampal neurons undergo increased mitochondrial fusion to modulate cellular activity as an adaptive mechanism in response to low dose radiation. PMID:26415228

  18. Persistence and financial markets

    NASA Astrophysics Data System (ADS)

    Jain, S.

    2007-09-01

    The persistence phenomenon is studied in a financial context by using a novel mapping of the time evolution of the values of shares in a portfolio onto Ising spins. The method is applied to historical data from the London Financial Times Stock Exchange 100 index (FTSE 100) over an arbitrarily chosen period. By following the time dependence of the spins, we find evidence for a power law decay of the proportion of shares that remain either above or below their ‘starting’ values. As a result, we estimate a persistence exponent for the underlying financial market to be ≈0.5. Preliminary results from computer simulations on persistence in the economic dynamics of a toy model appear to reproduce the behaviour observed in real markets.

  19. Why Do Delusions Persist?

    PubMed Central

    Corlett, Philip R.; Krystal, John H.; Taylor, Jane R.; Fletcher, Paul C.

    2009-01-01

    Delusions are bizarre and distressing beliefs that characterize certain mental illnesses. They arise without clear reasons and are remarkably persistent. Recent models of delusions, drawing on a neuroscientific understanding of learning, focus on how delusions might emerge from abnormal experience. We believe that these models can be extended to help us understand why delusions persist. We consider prediction error, the mismatch between expectancy and experience, to be central. Surprising events demand a change in our expectancies. This involves making what we have learned labile, updating and binding the memory anew: a process of memory reconsolidation. We argue that, under the influence of excessive prediction error, delusional beliefs are repeatedly reconsolidated, strengthening them so that they persist, apparently impervious to contradiction. PMID:19636384

  20. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    PubMed Central

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress 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. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  1. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics.

    PubMed

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F G; Rothermel, Beverly A; Lavandero, Sergio

    2012-01-01

    Endoplasmic reticulum (ER) stress 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. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER-mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  2. Oxidative stress, cardiolipin and mitochondrial dysfunction in nonalcoholic fatty liver disease

    PubMed Central

    Paradies, Giuseppe; Paradies, Valeria; Ruggiero, Francesca M; Petrosillo, Giuseppe

    2014-01-01

    Nonalcoholic fatty liver disease (NAFLD) is today considered the most common form of chronic liver disease, affecting a high proportion of the population worldwide. NAFLD encompasses a large spectrum of liver damage, ranging from simple steatosis to steatohepatitis, advanced fibrosis and cirrhosis. Obesity, hyperglycemia, type 2 diabetes and hypertriglyceridemia are the most important risk factors. The pathogenesis of NAFLD and its progression to fibrosis and chronic liver disease is still unknown. Accumulating evidence indicates that mitochondrial dysfunction plays a key role in the physiopathology of NAFLD, although the mechanisms underlying this dysfunction are still unclear. Oxidative stress is considered an important factor in producing lethal hepatocyte injury associated with NAFLD. Mitochondrial respiratory chain is the main subcellular source of reactive oxygen species (ROS), which may damage mitochondrial proteins, lipids and mitochondrial DNA. Cardiolipin, a phospholipid located at the level of the inner mitochondrial membrane, plays an important role in several reactions and processes involved in mitochondrial bioenergetics as well as in mitochondrial dependent steps of apoptosis. This phospholipid is particularly susceptible to ROS attack. Cardiolipin peroxidation has been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including NAFLD. In this review, we focus on the potential roles played by oxidative stress and cardiolipin alterations in mitochondrial dysfunction associated with NAFLD. PMID:25339807

  3. How mitochondrial dynamism orchestrates mitophagy

    PubMed Central

    Shirihai, Orian; Song, Moshi; Dorn, Gerald W

    2015-01-01

    Mitochondria are highly dynamic, except in adult cardiomyocytes. Yet, the fission and fusion-promoting proteins that mediate mitochondrial dynamism are highly expressed in, and essential to the normal functioning of, hearts. Here, we review accumulating evidence supporting important roles for mitochondrial fission and fusion in cardiac mitochondrial quality control, focusing on the PINK1-Parkin mitophagy pathway.Based in part on recent findings from in vivo mouse models in which mitofusin-mediated mitochondrial fusion or Drp1-mediated mitochondrial fission were conditionally interrupted in cardiac myocytes, we propose several new concepts that may provide insight into the cardiac mitochondrial dynamism-mitophagy interactome. PMID:25999423

  4. Mitochondrial oxidative stress mediates induction of autophagy and hypertrophy in angiotensin-II treated mouse hearts.

    PubMed

    Dai, Dao-Fu; Rabinovitch, Peter

    2011-08-01

    Autophagy is characterized by recycling of cellular organelles and can be induced by several stimuli, including nutrient deprivation and oxidative stress. As a major site of free radical production during oxidative phosphorylation, mitochondria are believed to be primary targets of oxidative damage during stress. Our recent study demonstrated that angiotensin II increases cardiac mitochondrial reactive oxygen species (ROS) production, causes a decline of mitochondrial membrane potential in cardiomyocytes and increases cardiac mitochondrial protein oxidative damage and mitochondrial DNA deletions. The deleterious effects of angiotensin II on mitochondria are associated with an increase in autophagosomes and increased signaling of mitochondrial biogenesis, interpreted as an attempt to replenish the damaged mitochondria and restore energy production. Direct evidence for the central role of mitochondrial ROS was investigated by comparing the effect on mice overexpressing catalase targeted to mitochondria (mCAT) and mice overexpressing peroxisomal targeted catalase (pCAT, the natural site of catalase) challenged by angiotensin II or Gαq overexpression. The mCAT, but not pCAT, mice are resistant to cardiac hypertrophy, fibrosis and mitochondrial damage, biogenesis and autophagy induced by angiotensin II, as well as heart failure induced by overexpression of Gαq. PMID:21505274

  5. The mitochondrial plasmid of the true slime mold Physarum polycephalum bypasses uniparental inheritance by promoting mitochondrial fusion.

    PubMed

    Sakurai, Rakusa; Nomura, Hideo; Moriyam, Yohsuke; Kawano, Shigeyuki

    2004-08-01

    Mitochondrial DNA (mtDNA) is inherited maternally in most eukaryotes. Linear mitochondrial plasmids in higher plants and fungi are also transmitted from the maternal parent to the progeny. However, mF, which is a mitochondrial linear plasmid of Physarum polycephalum, evades uniparental mitochondrial inheritance. We examined 36 myxamoebal strains of Physarum and isolated three novel mF+ strains (JE8, TU111, NG111) that harbored free mF plasmids. These strains were mated with the mF- strain KM88. Of the three mF- x mF+ crosses, only KM88 x JE8 displayed complete uniparental inheritance. However, in KM88 x TU111 and KM88 x NG111, the mtDNA of KM88 and mF of TU111 and NG111 were inherited by the plasmodia and showed recombination. For example, although the mtDNA of TU111 was eliminated, the mF of TU111 persisted and became inserted into the mtDNA of KM88, such that recombinant mtDNA represented 80% of the total mtDNA. The parental mitochondria fused to yield giant mitochondria with two or more mitochondrial nucleoids. The mF appears to exchange mitochondria from the recipient (paternal) to the donor (maternal) by promoting mitochondrial fusion. PMID:15179521

  6. Molecular Genetics of Mitochondrial Biogenesis in Maize.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mitochondrial genome encodes proteins essential for mitochondrial respiration and ATP synthesis. Nuclear gene products, however, are required for the expression of mitochondrial genes and the elaboration of functional mitochondrial protein complexes. We are exploiting a unique collection of maiz...

  7. Diabetic Retinopathy, Superoxide Damage and Antioxidants

    PubMed Central

    Santos, Julia M.; Mohammad, Ghulam; Zhong, Qing; Kowluru, Renu A.

    2011-01-01

    Retinopathy, the leading cause of acquired blindness in young adults, is one of the most feared complications of diabetes, and hyperglycemia is considered as the major trigger for its development. The microvasculature of the retina is constantly bombarded by high glucose, and this insult results in many metabolic, structural and functional changes. Retinal mitochondria become dysfunctional, its DNA is damaged and proteins encoded by its DNA are decreased. The electron transport chain system becomes compromised, further producing superoxide and providing no relief to the retina from a continuous cycle of damage. Although the retina attempts to initiate repair mechanisms by inducing gene expressions of the repair enzymes, their mitochondrial accumulation remains deficient. Understanding the molecular mechanism of mitochondrial damage should help identify therapies to treat/retard this sight threatening complication of diabetes. Our hope is that if the retinal mitochondria are maintained healthy with adjunct therapies, the development and progression of diabetic retinopathy can be inhibited. PMID:20939803

  8. The Spectrum of Mitochondrial Ultrastructural Defects in Mitochondrial Myopathy

    PubMed Central

    Vincent, Amy E.; Ng, Yi Shiau; White, Kathryn; Davey, Tracey; Mannella, Carmen; Falkous, Gavin; Feeney, Catherine; Schaefer, Andrew M.; McFarland, Robert; Gorman, Grainne S.; Taylor, Robert W.; Turnbull, Doug M.; Picard, Martin

    2016-01-01

    Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus provide insight into the underlying pathogenesis of inherited and acquired mitochondrial diseases. Following a systematic literature review on ultrastructural defects in mitochondrial myopathy, we investigated skeletal muscle biopsies from seven subjects with genetically defined mtDNA mutations. Mitochondrial ultrastructure and morphology were characterized using two complimentary approaches: transmission electron microscopy (TEM) and serial block face scanning EM (SBF-SEM) with 3D reconstruction. Six ultrastructural abnormalities were identified including i) paracrystalline inclusions, ii) linearization of cristae and abnormal angular features, iii) concentric layering of cristae membranes, iv) matrix compartmentalization, v) nanotunelling, and vi) donut-shaped mitochondria. In light of recent molecular advances in mitochondrial biology, these findings reveal novel aspects of mitochondrial ultrastructure and morphology in human tissues with implications for understanding the mechanisms linking mitochondrial dysfunction to disease. PMID:27506553

  9. The Spectrum of Mitochondrial Ultrastructural Defects in Mitochondrial Myopathy.

    PubMed

    Vincent, Amy E; Ng, Yi Shiau; White, Kathryn; Davey, Tracey; Mannella, Carmen; Falkous, Gavin; Feeney, Catherine; Schaefer, Andrew M; McFarland, Robert; Gorman, Grainne S; Taylor, Robert W; Turnbull, Doug M; Picard, Martin

    2016-01-01

    Mitochondrial functions are intrinsically linked to their morphology and membrane ultrastructure. Characterizing abnormal mitochondrial structural features may thus provide insight into the underlying pathogenesis of inherited and acquired mitochondrial diseases. Following a systematic literature review on ultrastructural defects in mitochondrial myopathy, we investigated skeletal muscle biopsies from seven subjects with genetically defined mtDNA mutations. Mitochondrial ultrastructure and morphology were characterized using two complimentary approaches: transmission electron microscopy (TEM) and serial block face scanning EM (SBF-SEM) with 3D reconstruction. Six ultrastructural abnormalities were identified including i) paracrystalline inclusions, ii) linearization of cristae and abnormal angular features, iii) concentric layering of cristae membranes, iv) matrix compartmentalization, v) nanotunelling, and vi) donut-shaped mitochondria. In light of recent molecular advances in mitochondrial biology, these findings reveal novel aspects of mitochondrial ultrastructure and morphology in human tissues with implications for understanding the mechanisms linking mitochondrial dysfunction to disease. PMID:27506553

  10. A Very Persistent Mistake

    ERIC Educational Resources Information Center

    McClelland, J. A. G.

    2011-01-01

    Articulated bodies with an internal energy source require to be coupled to an external mass in order to accelerate themselves but the typical text book assertion that the net force is provided by the external mass is not correct. Arguments are presented demonstrating that the assertion is incorrect and reasons are suggested for the persistence of…

  11. Retention and Persistence Data.

    ERIC Educational Resources Information Center

    Sanford, Timothy R.

    Two studies are combined with an introductory section: one is "Persistence to Graduation for Freshmen Entering the University of North Carolina at Chapel Hill, 1967-75," by Timothy Sanford, and the second is "Freshman, Transfer, Professional, Masters, and Doctoral Student Retention at the University of North Carolina at Chapel Hill," by Paul D.…

  12. The Persistence of PCBs.

    ERIC Educational Resources Information Center

    Boyle, Robert H.; Highland, Joseph H.

    1979-01-01

    PCB's are one of the most persistent chemicals ever introduced into the environment by man. From very early in their history of manufacture PCB's were suspected of being hazardous to health, but public awareness of the hazard was slow in coming. (RE)

  13. DNA damage in neurodegenerative diseases.

    PubMed

    Coppedè, Fabio; Migliore, Lucia

    2015-06-01

    Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis, which represent three of the most common neurodegenerative pathologies in humans. PMID:26255941

  14. Mitochondrial Dysfunction in Cancer

    PubMed Central

    Boland, Michelle L.; Chourasia, Aparajita H.; Macleod, Kay F.

    2013-01-01

    A mechanistic understanding of how mitochondrial dysfunction contributes to cell growth and tumorigenesis is emerging beyond Warburg as an area of research that is under-explored in terms of its significance for clinical management of cancer. Work discussed in this review focuses less on the Warburg effect and more on mitochondria and how dysfunctional mitochondria modulate cell cycle, gene expression, metabolism, cell viability, and other established aspects of cell growth and stress responses. There is increasing evidence that key oncogenes and tumor suppressors modulate mitochondrial dynamics through important signaling pathways and that mitochondrial mass and function vary between tumors and individuals but the significance of these events for cancer are not fully appreciated. We explore the interplay between key molecules involved in mitochondrial fission and fusion and in apoptosis, as well as in mitophagy, biogenesis, and spatial dynamics of mitochondria and consider how these distinct mechanisms are coordinated in response to physiological stresses such as hypoxia and nutrient deprivation. Importantly, we examine how deregulation of these processes in cancer has knock on effects for cell proliferation and growth. We define major forms of mitochondrial dysfunction and address the extent to which the functional consequences of such dysfunction can be determined and exploited for cancer diagnosis and treatment. PMID:24350057

  15. Mitochondrial fusion and inheritance of the mitochondrial genome.

    PubMed

    Takano, Hiroyoshi; Onoue, Kenta; Kawano, Shigeyuki

    2010-03-01

    Although maternal or uniparental inheritance of mitochondrial genomes is a general rule, biparental inheritance is sometimes observed in protists and fungi,including yeasts. In yeast, recombination occurs between the mitochondrial genomes inherited from both parents.Mitochondrial fusion observed in yeast zygotes is thought to set up a space for DNA recombination. In the last decade,a universal mitochondrial fusion mechanism has been uncovered, using yeast as a model. On the other hand, an alternative mitochondrial fusion mechanism has been identified in the true slime mold Physarum polycephalum.A specific mitochondrial plasmid, mF, has been detected as the genetic material that causes mitochondrial fusion in P. polycephalum. Without mF, fusion of the mitochondria is not observed throughout the life cycle, suggesting that Physarum has no constitutive mitochondrial fusion mechanism.Conversely, mitochondria fuse in zygotes and during sporulation with mF. The complete mF sequence suggests that one gene, ORF640, encodes a fusogen for Physarum mitochondria. Although in general, mitochondria are inherited uniparentally, biparental inheritance occurs with specific sexual crossing in P. polycephalum.An analysis of the transmission of mitochondrial genomes has shown that recombinations between two parental mitochondrial genomes require mitochondrial fusion,mediated by mF. Physarum is a unique organism for studying mitochondrial fusion. PMID:20196232

  16. SOS Response Induces Persistence to Fluoroquinolones in Escherichia coli

    PubMed Central

    Dörr, Tobias; Lewis, Kim; Vulić, Marin

    2009-01-01

    Bacteria can survive antibiotic treatment without acquiring heritable antibiotic resistance. We investigated persistence to the fluoroquinolone ciprofloxacin in Escherichia coli. Our data show that a majority of persisters to ciprofloxacin were formed upon exposure to the antibiotic, in a manner dependent on the SOS gene network. These findings reveal an active and inducible mechanism of persister formation mediated by the SOS response, challenging the prevailing view that persisters are pre-existing and formed purely by stochastic means. SOS-induced persistence is a novel mechanism by which cells can counteract DNA damage and promote survival to fluoroquinolones. This unique survival mechanism may be an important factor influencing the outcome of antibiotic therapy in vivo. PMID:20011100

  17. Renal Mitochondrial Cytopathies

    PubMed Central

    Emma, Francesco; Montini, Giovanni; Salviati, Leonardo; Dionisi-Vici, Carlo

    2011-01-01

    Renal diseases in mitochondrial cytopathies are a group of rare diseases that are characterized by frequent multisystemic involvement and extreme variability of phenotype. Most frequently patients present a tubular defect that is consistent with complete De Toni-Debré-Fanconi syndrome in most severe forms. More rarely, patients present with chronic tubulointerstitial nephritis, cystic renal diseases, or primary glomerular involvement. In recent years, two clearly defined entities, namely 3243 A > G tRNALEU mutations and coenzyme Q10 biosynthesis defects, have been described. The latter group is particularly important because it represents the only treatable renal mitochondrial defect. In this paper, the physiopathologic bases of mitochondrial cytopathies, the diagnostic approaches, and main characteristics of related renal diseases are summarized. PMID:21811680

  18. Concise Review: Heteroplasmic Mitochondrial DNA Mutations and Mitochondrial Diseases: Toward iPSC-Based Disease Modeling, Drug Discovery, and Regenerative Therapeutics.

    PubMed

    Hatakeyama, Hideyuki; Goto, Yu-Ichi

    2016-04-01

    Mitochondria contain multiple copies of their own genome (mitochondrial DNA; mtDNA). Once mitochondria are damaged by mutant mtDNA, mitochondrial dysfunction is strongly induced, followed by symptomatic appearance of mitochondrial diseases. Major genetic causes of mitochondrial diseases are defects in mtDNA, and the others are defects of mitochondria-associating genes that are encoded in nuclear DNA (nDNA). Numerous pathogenic mutations responsible for various types of mitochondrial diseases have been identified in mtDNA; however, it remains uncertain why mitochondrial diseases present a wide variety of clinical spectrum even among patients carrying the same mtDNA mutations (e.g., variations in age of onset, in affected tissues and organs, or in disease progression and phenotypic severity). Disease-relevant induced pluripotent stem cells (iPSCs) derived from mitochondrial disease patients have therefore opened new avenues for understanding the definitive genotype-phenotype relationship of affected tissues and organs in various types of mitochondrial diseases triggered by mtDNA mutations. In this concise review, we briefly summarize several recent approaches using patient-derived iPSCs and their derivatives carrying various mtDNA mutations for applications in human mitochondrial disease modeling, drug discovery, and future regenerative therapeutics. Stem Cells 2016;34:801-808. PMID:26850516

  19. A silybin-phospholipid complex prevents mitochondrial dysfunction in a rodent model of nonalcoholic steatohepatitis.

    PubMed

    Serviddio, Gaetano; Bellanti, Francesco; Giudetti, Anna Maria; Gnoni, Gabriele Vincenzo; Petrella, Antonio; Tamborra, Rosanna; Romano, Antonino Davide; Rollo, Tiziana; Vendemiale, Gianluigi; Altomare, Emanuele

    2010-03-01

    Mitochondrial dysfunction and oxidative stress are determinant events in the pathogenesis of nonalcoholic steatohepatitis. Silybin has shown antioxidant, anti-inflammatory, and antifibrotic effects in chronic liver disease. We aimed to study the effect of the silybin-phospholipid complex (SILIPHOS) on liver redox balance and mitochondrial function in a dietary model of nonalcoholic steatohepatitis. To accomplish this, glutathione oxidation, mitochondrial oxygen uptake, proton leak, ATP homeostasis, and H(2)O(2) production rate were evaluated in isolated liver mitochondria from rats fed a methionine- and choline-deficient (MCD) diet and the MCD diet plus SILIPHOS for 7 and 14 weeks. Oxidative proteins, hydroxynonenal (HNE)- and malondialdehyde (MDA)-protein adducts, and mitochondrial membrane lipid composition were also measured. Treatment with SILIPHOS limited glutathione depletion and mitochondrial H(2)O(2) production. Moreover, SILIPHOS preserved mitochondrial bioenergetics and prevented mitochondrial proton leak and ATP reduction. Finally, SILIPHOS limited the formation of HNE- and MDA-protein adducts. In conclusion, SILIPHOS is effective in preventing severe oxidative stress and preserving hepatic mitochondrial bioenergetics in nonalcoholic steatohepatitis induced by the MCD diet. The modifications of mitochondrial membrane fatty acid composition induced by the MCD diet are partially prevented by SILIPHOS, conferring anti-inflammatory and antifibrotic effects. The increased vulnerability of lipid membranes to oxidative damage is limited by SILIPHOS through preserved mitochondrial function. PMID:20008062

  20. Decreasing mitochondrial fission alleviates hepatic steatosis in a murine model of nonalcoholic fatty liver disease

    PubMed Central

    Galloway, Chad A.; Lee, Hakjoo; Brookes, Paul S.

    2014-01-01

    Mitochondria produce the majority of cellular ATP through oxidative phosphorylation, and their capacity to do so is influenced by many factors. Mitochondrial morphology is recently suggested as an important contributor in controlling mitochondrial bioenergetics. Mitochondria divide and fuse continuously, which is affected by environmental factors, including metabolic alterations. Underscoring its bioenergetic influence, altered mitochondrial morphology is reported in tissues of patients and in animal models of metabolic dysfunction. In this study, we found that mitochondrial fission plays a vital role in the progression of nonalcoholic fatty liver disease (NAFLD). The development of hepatic steatosis, oxidative/nitrative stress, and hepatic tissue damage, induced by a high-fat diet, were alleviated in genetically manipulated mice suppressing mitochondrial fission. The alleviation of steatosis was recapitulated in primary hepatocytes with the inhibition of mitochondrial fission. Mechanistically, our study indicates that fission inhibition enhances proton leak under conditions of free fatty acid incubation, implicating bioenergetic change through manipulating mitochondrial fission. Taken together, our results suggest a mechanistic role for mitochondrial fission in the etiology of NAFLD. The efficacy of decreasing mitochondrial fission in the suppression of NAFLD suggests that mitochondrial fission represents a novel target for therapeutic treatment of NAFLD. PMID:25080922

  1. Mitochondrial deficiency in Cockayne syndrome

    PubMed Central

    Scheibye-Knudsen, Morten; Croteau, Deborah L.; Bohr, Vilhelm A.

    2013-01-01

    Cockayne syndrome is a rare inherited disorder characterized by accelerated aging, cachectic dwarfism and many other features. Recent work has implicated mitochondrial dysfunction in the pathogenesis of this disease. This is particularly interesting since mitochondrial deficiencies are believed to be important in the aging process. In this review, we will discuss recent findings of mitochondrial pathology in Cockayne syndrome and suggest possible mechanisms for the mitochondrial dysfunction. PMID:23435289

  2. Mitochondrial-Derived Oxidants and Cellular Responses to Low Dose/Low LET Ionizing Radiation

    SciTech Connect

    Spitz, Douglas R.

    2009-11-09

    Exposure to ionizing radiation results in the immediate formation of free radicals and other reactive oxygen species (ROS). It has been assumed that the subsequent injury processes leading to genomic instability and carcinogenesis following radiation, derive from the initial oxidative damage caused by these free radicals and ROS. It is now becoming increasingly obvious that metabolic oxidation/reduction (redox) reactions can be altered by irradiation leading to persistent increases in steady-state levels of intracellular free radicals and ROS that contribute to the long term biological effects of radiation exposure by causing chronic oxidative stress. The objective during the last period of support (DE-FG02-05ER64050; 5/15/05-12/31/09) was to determine the involvement of mitochondrial genetic defects in metabolic oxidative stress and the biological effects of low dose/low LET radiation. Aim 1 was to determine if cells with mutations in succinate dehydrogenase (SDH) subunits C and D (SDHC and SDHD in mitochondrial complex II) demonstrated increases in steady-state levels of reactive oxygen species (ROS; O2•- and H2O2) as well as demonstrating increased sensitivity to low dose/low LET radiation (10 cGy) in cultured mammalian cells. Aim #2 was to determine if mitochondrially-derived ROS contributed to increased sensitivity to low dose/low LET radiation in mammalian cells containing mutations in SDH subunits. Aim #3 was to determine if a causal relationship existed between increases in mitochondrial ROS production, alterations in electron transport chain proteins, and genomic instability in the progeny of irradiated cells. Evidence gathered in the 2005-2009 period of support demonstrated that mutations in genes coding for mitochondrial electron transport chain proteins (ETC); either Succinate Dehydrogenase (SDH) subunit C (SDHC) or subunit D (SDHD); caused increased ROS production, increased genomic instability, and increased sensitivity to low dose/low LET radiation

  3. Cancer: Mitochondrial Origins

    PubMed Central

    Stefano, George B.; Kream, Richard M.

    2015-01-01

    The primacy of glucose derived from photosynthesis as an existential source of chemical energy across plant and animal phyla is universally accepted as a core principle in the biological sciences. In mammalian cells, initial processing of glucose to triose phosphate intermediates takes place within the cytosolic glycolytic pathway and terminates with temporal transport of reducing equivalents derived from pyruvate metabolism by membrane-associated respiratory complexes in the mitochondrial matrix. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionary fashioned chemiosmotic production of ATP as a high-efficiency biological process. The mechanistic bases of carcinogenesis have demonstrated profound alteration of normative mitochondrial function, notably dysregulated respiratory processes. Accordingly, the classic Warburg effect functionally links aerobic glycolysis, aberrant production and release of lactate, and metabolic down-regulation of mitochondrial oxidative processes with the carcinogenetic phenotype. We surmise, however, that aerobic fermentation by cancer cells may also represent a developmental re-emergence of an evolutionarily conserved early phenotype, which was “sidelined” with the emergence of mitochondrial oxidative phosphorylation as a primary mechanism for ATP production in normal cells. Regardless of state-dependent physiological status in mixed populations of cancer cells, it has been established that mitochondria are functionally linked to the initiation of cancer and its progression. Biochemical, molecular, and physiological differences in cancer cell mitochondria, notably mtDNA heteroplasmy and allele-specific expression of selected nuclear genes, may represent major focal points for novel targeting and elimination of cancer cells in metastatic disease afflicting human populations. To date, and despite considerable research efforts, the practical realization of advanced

  4. Pharmacologic Effects on Mitochondrial Function

    ERIC Educational Resources Information Center

    Cohen, Bruce H.

    2010-01-01

    The vast majority of energy necessary for cellular function is produced in mitochondria. Free-radical production and apoptosis are other critical mitochondrial functions. The complex structure, electrochemical properties of the inner mitochondrial membrane (IMM), and genetic control from both mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) are…

  5. Late Mitochondrial Acquisition, Really?

    PubMed Central

    Degli Esposti, Mauro

    2016-01-01

    This article provides a timely critique of a recent Nature paper by Pittis and Gabaldón that has suggested a late origin of mitochondria in eukaryote evolution. It shows that the inferred ancestry of many mitochondrial proteins has been incorrectly assigned by Pittis and Gabaldón to bacteria other than the aerobic proteobacteria from which the ancestor of mitochondria originates, thereby questioning the validity of their suggestion that mitochondrial acquisition may be a late event in eukaryote evolution. The analysis and approach presented here may guide future studies to resolve the true ancestry of mitochondria. PMID:27289097

  6. Involvement of mitochondrial dysfunction in nefazodone-induced hepatotoxicity.

    PubMed

    Silva, Ana Marta; Barbosa, Inês A; Seabra, Cátia; Beltrão, Nuno; Santos, Raquel; Vega-Naredo, Ignacio; Oliveira, Paulo J; Cunha-Oliveira, Teresa

    2016-08-01

    Nefazodone (NEF) is an antidepressive agent that was widely used in the treatment of depression until its withdrawal from the market, due to reports of liver injury and failure. NEF hepatotoxicity has been associated with mitochondrial impairment due to interference with the OXPHOS enzymatic activities, increased ROS generation and decreased antioxidant defenses. However, the mechanisms by which NEF induces mitochondrial dysfunction in hepatocytes are not completely understood. Here, we investigated the mitochondrial mechanisms affected upon NEF exposure and whether these might be linked to drug hepatotoxicity, in order to infer liabilities of future drug candidates. Two moderately hepatotoxic NEF concentrations (20 and 50 μM) were selected from dose-response growth curves performed in HepG2 cells. Cell viability, caspase activity, nuclear morphology, mitochondrial transmembrane potential, mitochondrial superoxide levels, and the expression of genes associated with different cellular pathways were evaluated at different time points. NEF treatment led to an increase in the expression of genes associated with DNA-damage response, antioxidant defense and apoptosis and a decreased expression of genes encoding proteins involved in oxidative phosphorylation, DNA repair, cell proliferation and cell cycle progression, which seem to constitute mechanisms underlying the observed mitochondrial and cell function impairment. PMID:27288927

  7. Dysfunctional Mitochondrial Dynamics in the Pathophysiology of Neurodegenerative Diseases

    PubMed Central

    Haun, Florian; Nakamura, Tomohiro; Lipton, Stuart A

    2013-01-01

    Mitochondrial dysfunction occurs in neurodegenerative diseases, however molecular mechanisms underlying this process remain elusive. Emerging evidence suggests that nitrosative stress, mediated by reactive nitrogen species (RNS), may play a role in mitochondrial pathology. Here, we review findings that highlight the abnormal mitochondrial morphology observed in many neurodegenerative disorders including Alzheimer’s, Parkinson’s, and Huntington’s diseases. One mechanism whereby RNS can affect mitochondrial function and thus neuronal survival occurs via protein S-nitrosylation, representing chemical reaction of a nitric oxide (NO) group with a critical cysteine thiol. In this review, we focus on the signaling pathway whereby S-nitrosylation of the mitochondrial fission protein Drp1 (dynamin-related protein 1; forming S-nitrosothiol (SNO)-Drp1) precipitates excessive mitochondrial fission or fragmentation and consequent bioenergetic compromise. Subsequently, the formation of SNO-Drp1 leads to synaptic damage and neuronal death. Thus, intervention in the SNO-Drp1 pathway may provide therapeutic benefit in neurodegenerative diseases. PMID:24587691

  8. Delaying the mitochondrial decay of aging with acetylcarnitine.

    PubMed

    Ames, Bruce N; Liu, Jiankang

    2004-11-01

    Oxidative mitochondrial decay is a major contributor to aging. Some of this decay can be reversed in old rats by feeding them normal mitochondrial metabolites, acetylcarnitine (ALC) and lipoic acid (LA), at high levels. Feeding the substrate ALC with LA, a mitochondrial antioxidant, restores the velocity of the reaction (K(m)) for ALC transferase and mitochondrial function. The principle appears to be that, with age, increased oxidative damage to protein causes a deformation of structure of key enzymes with a consequent lessening of affinity (K(m)) for the enzyme substrate. The effect of age on the enzyme-binding affinity can be mimicked by reacting it with malondialdehyde (a lipid peroxidation product that increases with age). In old rats (vs. young rats), mitochondrial membrane potential, cardiolipin level, respiratory control ratio, and cellular O(2) uptake are lower; oxidants/O(2), neuron RNA oxidation, and mutagenic aldehydes from lipid peroxidation are higher. Ambulatory activity and cognition decline with age. Feeding old rats ALC with LA for a few weeks restores mitochondrial function; lowers oxidants, neuron RNA oxidation, and mutagenic aldehydes; and increases rat ambulatory activity and cognition (as assayed with the Skinner box and Morris water maze). A recent meta-analysis of 21 double-blind clinical trials of ALC in the treatment of mild cognitive impairment and mild Alzheimer's disease showed significant efficacy vs. placebo. A meta-analysis of 4 clinical trials of LA for treatment of neuropathic deficits in diabetes showed significant efficacy vs. placebo. PMID:15591008

  9. Mitochondrial toxicity of depleted uranium: protection by Beta-glucan.

    PubMed

    Shaki, Fatemeh; Pourahmad, Jalal

    2013-01-01

    Considerable evidence suggests that mitochondrial dysfunction contributes to the toxicity of uranyl acetate (UA), a soluble salt of depleted uranium (DU). We examined the ability of the two antioxidants, beta-glucan and butylated hydroxyl toluene (BHT), to prevent UA-induced mitochondrial dysfunction using rat-isolated kidney mitochondria. Beta-glucan (150 nM) and BHT (20 nM) attenuated UA-induced mitochondrial reactive oxygen species (ROS) formation, lipid peroxidation and glutathione oxidation. Beta-glucan and BHT also prevented the loss of mitochondrial membrane potential (MMP) and mitochondrial swelling following the UA treatment in isolated mitochondria. Our results show that beta-glucan and BHT prevented UA-induced mitochondrial outer membrane damage as well as release of cytochrome c from mitochondria. UA also decreased the ATP production in isolated mitochondria significantly inhibited with beta-glucan and BHT pre-treatment. Our results showed that beta-glucan may be mitochondria-targeted antioxidant and suggested this compound as a possible drug candidate for prophylaxis and treatment against DU-induced nephrotoxicity. PMID:24250581

  10. Persistent fetal circulation.

    PubMed

    Saucier, P H

    1980-01-01

    A review of persistent fetal circulation, which involves the presence of a right to left extrapulmonary shunt that is sustained into neonatal life, is presented. Clinical signs exhibited by the infant often resemble those of respiratory distress. Treatment is accomplished with hyperventilation and/or pharmacologically with tolazoline which, in addition to the usual attention to the overall condition of the infant, requires intensive monitoring by the nurse. PMID:6898712

  11. Persistent interface fluid syndrome.

    PubMed

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2008-08-01

    We present an unusual case of persistent interface fluid that would not resolve despite normal intraocular pressure and corneal endothelial replacement with Descemet-stripping endothelial keratoplasty. Dissection, elevation, and repositioning of the laser in situ keratomileusis flap were required to resolve the interface fluid. Circumferential corneal graft-host margin scar formation acting as a mechanical strut may have been the cause of the intractable interface fluid. PMID:18655997

  12. Restriction enzyme analysis of the mitochondrial genome in mitochondrial myopathy.

    PubMed Central

    Poulton, J; Turnbull, D M; Mehta, A B; Wilson, J; Gardiner, R M

    1988-01-01

    The mitochondrial myopathies are a heterogeneous group of disorders some of which may be caused by mutations in the mitochondrial genome. Mitochondrial DNA from 10 patients with mitochondrial myopathy and their mothers was analysed using five restriction enzymes and 11 mitochondrial probes in bacteriophage M13. No abnormalities were found in seven out of the 10 patients. Polymorphisms which have not previously been reported were detected in three patients and two of their mothers. These results exclude the presence of deletions or insertions of greater than 60 bp in the region of the mitochondrial genome examined. Any causative mitochondrial DNA mutations in these disorders are therefore likely to be point mutations or small structural rearrangements. Images PMID:2903249

  13. Increased ER–mitochondrial coupling promotes mitochondrial respiration and bioenergetics during early phases of ER stress

    PubMed Central

    Bravo, Roberto; Vicencio, Jose Miguel; Parra, Valentina; Troncoso, Rodrigo; Munoz, Juan Pablo; Bui, Michael; Quiroga, Clara; Rodriguez, Andrea E.; Verdejo, Hugo E.; Ferreira, Jorge; Iglewski, Myriam; Chiong, Mario; Simmen, Thomas; Zorzano, Antonio; Hill, Joseph A.; Rothermel, Beverly A.; Szabadkai, Gyorgy; Lavandero, Sergio

    2011-01-01

    Increasing evidence indicates that endoplasmic reticulum (ER) stress activates the adaptive unfolded protein response (UPR), but that beyond a certain degree of ER damage, this response triggers apoptotic pathways. The general mechanisms of the UPR and its apoptotic pathways are well characterized. However, the metabolic events that occur during the adaptive phase of ER stress, before the cell death response, remain unknown. Here, we show that, during the onset of ER stress, the reticular and mitochondrial networks are redistributed towards the perinuclear area and their points of connection are increased in a microtubule-dependent fashion. A localized increase in mitochondrial transmembrane potential is observed only in redistributed mitochondria, whereas mitochondria that remain in other subcellular zones display no significant changes. Spatial re-organization of these organelles correlates with an increase in ATP levels, oxygen consumption, reductive power and increased mitochondrial Ca2+ uptake. Accordingly, uncoupling of the organelles or blocking Ca2+ transfer impaired the metabolic response, rendering cells more vulnerable to ER stress. Overall, these data indicate that ER stress induces an early increase in mitochondrial metabolism that depends crucially upon organelle coupling and Ca2+ transfer, which, by enhancing cellular bioenergetics, establishes the metabolic basis for the adaptation to this response. PMID:21628424

  14. Mitochondrial genome acquisition restores respiratory function and tumorigenic potential of cancer cells without mitochondrial DNA.

    PubMed

    Tan, An S; Baty, James W; Dong, Lan-Feng; Bezawork-Geleta, Ayenachew; Endaya, Berwini; Goodwin, Jacob; Bajzikova, Martina; Kovarova, Jaromira; Peterka, Martin; Yan, Bing; Pesdar, Elham Alizadeh; Sobol, Margarita; Filimonenko, Anatolyj; Stuart, Shani; Vondrusova, Magdalena; Kluckova, Katarina; Sachaphibulkij, Karishma; Rohlena, Jakub; Hozak, Pavel; Truksa, Jaroslav; Eccles, David; Haupt, Larisa M; Griffiths, Lyn R; Neuzil, Jiri; Berridge, Michael V

    2015-01-01

    We report that tumor cells without mitochondrial DNA (mtDNA) show delayed tumor growth, and that tumor formation is associated with acquisition of mtDNA from host cells. This leads to partial recovery of mitochondrial function in cells derived from primary tumors grown from cells without mtDNA and a shorter lag in tumor growth. Cell lines from circulating tumor cells showed further recovery of mitochondrial respiration and an intermediate lag to tumor growth, while cells from lung metastases exhibited full restoration of respiratory function and no lag in tumor growth. Stepwise assembly of mitochondrial respiratory (super)complexes was correlated with acquisition of respiratory function. Our findings indicate horizontal transfer of mtDNA from host cells in the tumor microenvironment to tumor cells with compromised respiratory function to re-establish respiration and tumor-initiating efficacy. These results suggest pathophysiological processes for overcoming mtDNA damage and support the notion of high plasticity of malignant cells. PMID:25565207

  15. Persistent fetal circulation

    PubMed Central

    D’cunha, Chrysal; Sankaran, Koravangattu

    2001-01-01

    Persistent fetal circulation (PFC), also known as persistent pulmonary hypertension of the newborn, is defined as postnatal persistence of right-to-left ductal or atrial shunting, or both in the presence of elevated right ventricular pressure. It is a relatively rare condition that is usually seen in newborns with respiratory distress syndrome, overwhelming sepsis, meconium and other aspiration syndromes, intrauterine hypoxia and ischemia, and/or neonatal hypoxia and ischemia. This condition causes severe hypoxemia, and, as a result, has significant morbidity and mortality. Improved antenatal and neonatal care; the use of surfactant; continuous monitoring of oxygenation, blood pressure and other vital functions; and early recognition and intervention have made this condition even more rare. In modern neonatal intensive care units, anticipation and early treatment of PFC and its complications in sick newborns are commonplace. Thus, severe forms of PFC are only seen on isolated occasions. Consequently, it is even more imperative to revisit PFC compared with the time when there were occasional cases of PFC seen in neonatal intensive care units, and to discuss evolving treatment and management issues that pertain to this syndrome. PMID:20084150

  16. Dysregulation of Mitochondrial Dynamics and the Muscle Transcriptome in ICU Patients Suffering from Sepsis Induced Multiple Organ Failure

    PubMed Central

    Fredriksson, Katarina; Tjäder, Inga; Keller, Pernille; Petrovic, Natasa; Ahlman, Bo; Schéele, Camilla; Wernerman, Jan; Timmons, James A.; Rooyackers, Olav

    2008-01-01

    Background Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patient's protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients impairing cellular energy balance, which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments and the molecular consequences. Methodology/Principal Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2α/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and

  17. Mitochondrial dysfunction in DDR-related cancer predisposition syndromes.

    PubMed

    Lyakhovich, Alex; Graifer, Dmitry; Stefanovie, Barbora; Krejci, Lumir

    2016-04-01

    Given the key role of mitochondria in various cellular events, it is not surprising that mitochondrial dysfunction (MDF) is seen in many pathological conditions, in particular cancer. The mechanisms defining MDF are not clearly understood and may involve genetic defects, misbalance of reactive oxygen species (ROS), impaired autophagy (mitophagy), acquired mutations in mitochondrial or nuclear DNA and inability of cells to cope with the consequences. The importance of MDF arises from its detection in the syndromes with defective DNA damage response (DDR) and cancer predisposition. Here, we will focus on the dual role of these syndromes in cancer predisposition and MDF with specific emphasis on impaired autophagy. PMID:26926806

  18. Elastocapillary Instability in Mitochondrial Fission

    NASA Astrophysics Data System (ADS)

    Gonzalez-Rodriguez, David; Sart, Sébastien; Babataheri, Avin; Tareste, David; Barakat, Abdul I.; Clanet, Christophe; Husson, Julien

    2015-08-01

    Mitochondria are dynamic cell organelles that constantly undergo fission and fusion events. These dynamical processes, which tightly regulate mitochondrial morphology, are essential for cell physiology. Here we propose an elastocapillary mechanical instability as a mechanism for mitochondrial fission. We experimentally induce mitochondrial fission by rupturing the cell's plasma membrane. We present a stability analysis that successfully explains the observed fission wavelength and the role of mitochondrial morphology in the occurrence of fission events. Our results show that the laws of fluid mechanics can describe mitochondrial morphology and dynamics.

  19. ENERGETICS, EPIGENETICS, MITOCHONDRIAL GENETICS

    PubMed Central

    Wallace, Douglas C.; Fan, Weiwei

    2011-01-01

    The epigenome has been hypothesized to provide the interface between the environment and the nuclear DNA (nDNA) genes. Key factors in the environment are the availability of calories and demands on the organism’s energetic capacity. Energy is funneled through glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), the cellular bioenergetic systems. Since there are thousands of bioenergetic genes dispersed across the chromosomes and mitochondrial DNA (mtDNA), both cis and trans regulation of the nDNA genes is required. The bioenergetic systems convert environmental calories into ATP, acetyl-Coenzyme A (acetyl-CoA), S-adenosyl-methionine (SAM), and reduced NAD+. When calories are abundant, ATP and acetyl-CoA phosphorylate and acetylate chromatin, opening the nDNA for transcription and replication. When calories are limiting, chromatin phosphorylation and acetylation are lost and gene expression is suppressed. DNA methylaton via SAM can also be modulated by mitochondrial function. Phosphorylation and acetylation are also pivotal to regulating cellular signal transduction pathways. Therefore, bioenergetics provides the interface between the environment and the epigenome. Consistent with this conclusion, the clinical phenotypes of bioenergetic diseases are strikingly similar to those observed in epigenetic diseases (Angelman, Rett, Fragile X Syndromes, the laminopathies, cancer, etc.), and an increasing number of epigenetic diseases are being associated with mitochondrial dysfunction. This bioenergetic-epigenomic hypothesis has broad implications for the etiology, pathophysiology, and treatment of a wide range of common diseases. PMID:19796712

  20. Mitochondrial Ion Channels

    PubMed Central

    O’Rourke, Brian

    2009-01-01

    In work spanning more than a century, mitochondria have been recognized for their multifunctional roles in metabolism, energy transduction, ion transport, inheritance, signaling, and cell death. Foremost among these tasks is the continuous production of ATP through oxidative phosphorylation, which requires a large electrochemical driving force for protons across the mitochondrial inner membrane. This process requires a membrane with relatively low permeability to ions to minimize energy dissipation. However, a wealth of evidence now indicates that both selective and nonselective ion channels are present in the mitochondrial inner membrane, along with several known channels on the outer membrane. Some of these channels are active under physiological conditions, and others may be activated under pathophysiological conditions to act as the major determinants of cell life and death. This review summarizes research on mitochondrial ion channels and efforts to identify their molecular correlates. Except in a few cases, our understanding of the structure of mitochondrial ion channels is limited, indicating the need for focused discovery in this area. PMID:17059356

  1. Protons Trigger Mitochondrial Flashes.

    PubMed

    Wang, Xianhua; Zhang, Xing; Huang, Zhanglong; Wu, Di; Liu, Beibei; Zhang, Rufeng; Yin, Rongkang; Hou, Tingting; Jian, Chongshu; Xu, Jiejia; Zhao, Yan; Wang, Yanru; Gao, Feng; Cheng, Heping

    2016-07-26

    Emerging evidence indicates that mitochondrial flashes (mitoflashes) are highly conserved elemental mitochondrial signaling events. However, which signal controls their ignition and how they are integrated with other mitochondrial signals and functions remain elusive. In this study, we aimed to further delineate the signal components of the mitoflash and determine the mitoflash trigger mechanism. Using multiple biosensors and chemical probes as well as label-free autofluorescence, we found that the mitoflash reflects chemical and electrical excitation at the single-organelle level, comprising bursting superoxide production, oxidative redox shift, and matrix alkalinization as well as transient membrane depolarization. Both electroneutral H(+)/K(+) or H(+)/Na(+) antiport and matrix proton uncaging elicited immediate and robust mitoflash responses over a broad dynamic range in cardiomyocytes and HeLa cells. However, charge-uncompensated proton transport, which depolarizes mitochondria, caused the opposite effect, and steady matrix acidification mildly inhibited mitoflashes. Based on a numerical simulation, we estimated a mean proton lifetime of 1.42 ns and diffusion distance of 2.06 nm in the matrix. We conclude that nanodomain protons act as a novel, to our knowledge, trigger of mitoflashes in energized mitochondria. This finding suggests that mitoflash genesis is functionally and mechanistically integrated with mitochondrial energy metabolism. PMID:27463140

  2. OMA1 mediates OPA1 proteolysis and mitochondrial fragmentation in experimental models of ischemic kidney injury

    PubMed Central

    Xiao, Xiao; Hu, Yanzhong; Quirós, Pedro M.; Wei, Qingqing; López-Otín, Carlos

    2014-01-01

    Acute kidney injury (AKI) is associated with mitochondrial fragmentation, which contributes to mitochondrial damage and tubular cell apoptosis. Mitochondrial fragmentation involves the cleavage of both mitochondrial outer and inner membranes. Cleavage of the outer membrane results from Drp-1-mediated fission activation and Bak-promoted fusion arrest, but the molecular mechanism of inner membrane cleavage remains elusive. OMA1-mediated proteolysis of OPA1, a key inner membrane fusion protein, was recently suggested to account for inner membrane cleavage during cell stress. In this study, we determined the role of OMA1 in OPA1 proteolysis and mitochondrial fragmentation in experimental models of ischemic AKI. In ATP-depletion injury, knockdown of OMA1 suppressed OPA1 proteolysis, mitochondrial fragmentation, cytochrome c release, and consequent apoptosis in renal proximal tubular cells. In mice, OMA1 deficiency prevented ischemic AKI as indicated by better renal function, less tubular damage, and lower apoptosis. OPA1 proteolysis and mitochondrial injury during ischemic AKI were ameliorated in OMA1-deficient mice. Thus, OMA1-mediated OPA1 proteolysis plays an important role in the disruption of mitochondrial dynamics in ischemic AKI. PMID:24671334

  3. HIV alters neuronal mitochondrial fission/fusion in the brain during HIV-Associated Neurocognitive Disorders

    PubMed Central

    Fields, Jerel Adam; Serger, Elisabeth; Campos, Sofia; Divakaruni, Ajit S.; Kim, Changyoun; Smith, Kendall; Trejo, Margarita; Adame, Anthony; Spencer, Brian; Rockenstein, Edward; Murphy, Anne N.; Ellis, Ronald J.; Letendre, Scott; Grant, Igor; Masliah, Eliezer

    2015-01-01

    HIV-associated neurocognitive disorders (HAND) still occur in approximately 50% of HIV patients, and therapies to combat HAND progression are urgently needed. HIV proteins are released from infected cells and cause neuronal damage, possibly through mitochondrial abnormalities. Altered mitochondrial fission and fusion is implicated in several neurodegenerative disorders. Here, we hypothesized that mitochondrial fission/fusion may be dysregulated in neurons during HAND. We have identified decreased mitochondrial fission protein (dynamin 1-like; DNM1L) in frontal cortex tissues of HAND donors, along with enlarged and elongated mitochondria localized to the soma of damaged neurons. Similar pathology was observed in the brains of GFAP-gp120 tg mice. In vitro, recombinant gp120 decreased total and active DNM1L levels, reduced the level of Mitotracker staining, and increased extracellular acidification rate (ECAR) in primary neurons. DNM1L knockdown enhanced the effects of gp120 as measured by reduced Mitotracker signal in the treated cells. Interestingly, overexpression of DNM1L increased the level of Mitotracker staining in primary rat neurons and reduced neuroinflammation and neurodegeneration in the GFAP-gp120-tg mice. These data suggest that mitochondrial biogenesis dynamics are shifted towards mitochondrial fusion in brains of HAND patients and this may be due to gp120-induced reduction in DNM1L activity. Promoting mitochondrial fission during HIV infection of the CNS may restore mitochondrial biogenesis and prevent neurodegeneration. PMID:26611103

  4. Status epilepticus triggers early mitochondrial fusion in the rat hippocampus in a lithium-pilocarpine model.

    PubMed

    Córdova-Dávalos, Laura; Carrera-Calvo, Dulce; Solís-Navarrete, Jael; Mercado-Gómez, Octavio Fabián; Arriaga-Ávila, Virginia; Agredano-Moreno, Lourdes Teresa; Jiménez-García, Luis Felipe; Guevara-Guzmán, Rosalinda

    2016-07-01

    Many reports investigating the hippocampus have demonstrated an increase in neuronal damage, cellular loss, oxidative stress and mitochondrial DNA damage during status epilepticus (SE); however, information regarding alterations in mitochondrial fission and fusion events in SE is lacking. The aim of the present study was to examine the possible imbalance between mitochondrial fission and fusion in the hippocampus of male rats after acute seizure mediated by SE. In this study, we used ninety animals were randomly divided into control and SE groups and subjected to the lithium-pilocarpine model of epilepsy. Hippocampi were obtained at 3, 24 and 72h after SE, and the cytoplasmic and mitochondrial fractions of the cells were used to analyze changes in the Drp1 and Fis1 fission proteins and the Mfn1 and Opa1 fusion proteins by western blot analysis. Moreover, changes in the expression of fission and fusion mRNA transcripts were evaluated by real-time PCR. Mitochondrial morphology was also analyzed using standard transmission electron microscopy. Our data showed that the fission-related mRNA Drp1 was down-regulated rapidly after SE, while Fis1 did not show any significant changes in expression. Moreover, the mitochondrial fusion-associated proteins Mfn1 and Opa1 exhibited an increase in expression at 72h after SE. Electron microphotography revealed several morphological changes, such as swollen mitochondria and damage of the inner mitochondrial membrane, at 24h; at 72h elongation of some mitochondrial was also observed. Our results suggest that after the initiation of SE, the main regulator of the fission mRNA Drp1 is down-regulated, which in turn regulates mitochondrial fission and leads to an increase in the Mfn1 and Opa1 proteins to induce mitochondrial fusion, suggesting an imbalance of the fission and fusion processes. PMID:27045873

  5. Effects of Mitochondrial Translocation of Telomerase on Drug Resistance in Hepatocellular Carcinoma Cells

    PubMed Central

    Yan, Jing; Zhou, Yuan; Chen, DaiXing; Li, LiLi; Yang, Xin; You, Yang; Ling, Xianlong

    2015-01-01

    Hepatocellular carcinoma (HCC) cells exhibit multidrug resistance (MDR), but the underlying mechanisms remain unclear. Cancer cells that overexpress telomerase are resistant to chemotherapeutic drugs. This study aimed to determine the effects of mitochondrial translocation of telomerase on MDR in HCC cells. HepG2 cells were transfected with negative plasmid and PTPN11 (Shp-2) short hairpin RNA (ShRNA) plasmid to establish HepG2-negative (HepG2 transfected with negative plasmid) and HepG2-ShShp-2 (HepG2 transfected with Shp-2 ShRNA plasmid) cells. Sensitivity to chemotherapeutic drugs was assessed by Cell Counting Kit-8 (CCK-8) assays. Distribution of human telomerase reverse transcriptase (hTERT) within mitochondria was detected by western blotting and immunofluorescence combined with laser scanning confocal microscopy. Mitochondrial reactive oxygen species (ROS) generation was demonstrated by flow cytometry with the mitochondrial superoxide (Mito-Sox) indicator. The frequency of damaged mitochondrial DNA (mtDNA) was illustrated by quantitative real-time polymerase chain reaction (Q-PCR). Expression of mitochondrial respiratory chain complex subunits ND1 and COXII were also demonstrated by western blotting. Knockdown of Shp-2 in HepG2 cells resulted in upregulation of mitochondrial TERT expression and increased resistance to cisplatin (CDDP) and 5-fluorouracil (5-FU) (resistance indices, 2.094 and 1.863, respectively). In addition, both the mitochondrial ROS and the frequency of mtDNA damage were decreased, and COXII expression was upregulated. Our results suggest that Mitochondrial translocation of hTERT may lead to chemotherapeutic resistance in HCC cells. Mitochondrial hTERT contributes to the drug resistance of tumor cells by reducing ROS production and mtDNA damage, and exerting a protective effect on the mitochondrial respiratory chain. PMID:25561980

  6. Mitochondrial genome changes and neurodegenerative diseases☆

    PubMed Central

    Pinto, Milena; Moraes, Carlos T.

    2014-01-01

    Mitochondria are essential organelles within the cell where most of the energy production occurs by the oxidative phosphorylation system (OXPHOS). Critical components of the OXPHOS are encoded by the mitochondrial DNA (mtDNA) and therefore, mutations involving this genome can be deleterious to the cell. Post-mitotic tissues, such as muscle and brain, are most sensitive to mtDNA changes, due to their high energy requirements and non-proliferative status. It has been proposed that mtDNA biological features and location make it vulnerable to mutations, which accumulate over time. However, although the role of mtDNA damage has been conclusively connected to neuronal impairment in mitochondrial diseases, its role in age-related neurodegenerative diseases remains speculative. Here we review the pathophysiology of mtDNA mutations leading to neurodegeneration and discuss the insights obtained by studying mouse models of mtDNA dysfunction. This article is part of a Special Issue entitled: Misfolded Proteins, Mitochondrial Dysfunction, and Neurodegenerative Diseases. PMID:24252612

  7. Mitochondrial DNA hypomethylation in chrome plating workers.

    PubMed

    Yang, Linqing; Xia, Bo; Yang, Xueqin; Ding, Hong; Wu, Desheng; Zhang, Huimin; Jiang, Gaofeng; Liu, Jianjun; Zhuang, Zhixiong

    2016-01-22

    A matched case-control study was conducted to examine the relationship between chromium (Cr) exposure and variation in mitochondrial (mt) DNA methylation. We enrolled 29 pairs of subjects in this study; Cr exposure was confirmed in the cases by detecting blood Cr and other metal ion concentrations. DNA damage caused by Cr exposure was determined in terms of binucleated micronucleus frequency (BNMN) and mtDNA copy number. Finally, a Sequenom MassARRAY platform was applied to inspect the DNA methylation levels of mitochondrially encoded tRNA phenylalanine (MT-TF), mitochondrially encoded 12S RNA (MT-RNR1), and long interspersed nucleotide element-1 (LINE-1) genes. The blood Cr ion concentration and micronucleus frequency of the Cr-exposed group were higher than those of the control group, whereas the mtDNA copy number remained unchanged. The methylation levels of MT-TF and MT-RNR1 but not LINE-1 were significantly lower in Cr-exposed workers. Pearson correlation analysis showed that workers with higher blood Cr ion concentrations exhibited lower MT-TF and MT-RNR1 gene methylation, and multiple linear regression analysis indicated that CpG sites 1 and 2 in MT-TF and CpG site 6 in MT-RNR1 were affected. These results suggested that methylation level of mtDNA has the possibility of acting as an alternative effect biomarker for Cr exposure. PMID:26656300

  8. Mitochondrial dynamics and cell death in heart failure.

    PubMed

    Marín-García, José; Akhmedov, Alexander T

    2016-03-01

    The highly regulated processes of mitochondrial fusion (joining), fission (division) and trafficking, collectively called mitochondrial dynamics, determine cell-type specific morphology, intracellular distribution and activity of these critical organelles. Mitochondria are critical for cardiac function, while their structural and functional abnormalities contribute to several common cardiovascular diseases, including heart failure (HF). The tightly balanced mitochondrial fusion and fission determine number, morphology and activity of these multifunctional organelles. Although the intracellular architecture of mature cardiomyocytes greatly restricts mitochondrial dynamics, this process occurs in the adult human heart. Fusion and fission modulate multiple mitochondrial functions, ranging from energy and reactive oxygen species production to Ca(2+) homeostasis and cell death, allowing the heart to respond properly to body demands. Tightly controlled balance between fusion and fission is of utmost importance in the high energy-demanding cardiomyocytes. A shift toward fission leads to mitochondrial fragmentation, while a shift toward fusion results in the formation of enlarged mitochondria and in the fusion of damaged mitochondria with healthy organelles. Mfn1, Mfn2 and OPA1 constitute the core machinery promoting mitochondrial fusion, whereas Drp1, Fis1, Mff and MiD49/51 are the core components of fission machinery. Growing evidence suggests that fusion/fission factors in adult cardiomyocytes play essential noncanonical roles in cardiac development, Ca(2+) signaling, mitochondrial quality control and cell death. Impairment of this complex circuit causes cardiomyocyte dysfunction and death contributing to heart injury culminating in HF. Pharmacological targeting of components of this intricate network may be a novel therapeutic modality for HF treatment. PMID:26872674

  9. The genetics of mitochondrial disease.

    PubMed

    Davis, Ryan L; Sue, Carolyn M

    2011-11-01

    The discovery that defects in mitochondria and mitochondrial DNA could cause human disease has led to the development of a rapidly expanding group of disorders known as mitochondrial disease. Mitochondrial disease is so named because of the common feature of impaired mitochondrial function. The main function of the mitochondrion is to produce energy for the cell in the form of ATP. ATP is generated by the respiratory chain, a series of complex proteins that are located in the mitochondrial membrane, and are encoded for by both the mitochondrial and nuclear genomes. Consequently, mitochondrial disease can be caused by mutations in either mitochondrial or nuclear DNA. Given the distribution of mitochondria throughout the body, the specific properties of mitochondrial DNA, and the mitochondrion's dependence on nuclear genes for its normal function, the clinical presentation of mitochondrial disease can be highly variable. Thus, familiarity with typical clinical presentations and knowledge of the genes that contribute to mitochondrial function will aid the clinician in the recognition, diagnosis, and management of patients with this group of diverse disorders. PMID:22266889

  10. Dopamine Coupling to Mitochondrial Signaling: Implications for Transplantation.

    PubMed

    Stefano, George B; Ramin, Rohina; Kream, Richard M

    2016-01-01

    The persistence of major medical disorders afflicting millions of humans worldwide involves a functional pathophysiological coupling of systemic pro-inflammatory processes and tissue hypoxia. Mechanistically, reciprocal triggering of multiple ischemic/hypoxic and pro-inflammatory events, if not corrected, will promote pathophysiological amplification leading to a deleterious cascade of bio-senescent cellular and molecular signaling pathways that converge to markedly impair mitochondrial energy production. Given the level of energy production and utilization that can vary in and between cells and regionally in the same type of cells found in the body, e.g., dopamine neurons, the metabolic energy regulator, the mitochondrion, assumes a high position in the potential to maintain normal health and develop abnormal activities, resulting in chronic pathologies. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionarily fashioned chemiosmotic production of ATP as a high-efficiency biological proton pump process. The mechanistic evolutionary bases of diabetes have demonstrated the profound alteration of normative mitochondrial function, notably deregulated respiratory processes. This same phenomenon provides evidence of mitochondrial linkages to neurological disorders, such as Parkinson's disease. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial targeted therapies has not been forthcoming. PMID:26790458

  11. Learning's "Weak" Link to Persistence

    ERIC Educational Resources Information Center

    Wolniak, Gregory C.; Mayhew, Matthew J.; Engberg, Mark E.

    2012-01-01

    This study advances the understanding of college persistence by examining five dimensions of student learning in relation to second-year persistence. Two of the five dimensions of learning were found to be significant predictors of persistence, and each was moderated by social integration. (Contains 5 tables and 1 figure.)

  12. Oxidative stress modulates mitochondrial failure and cyclophilin D function in X-linked adrenoleukodystrophy

    PubMed Central

    López-Erauskin, Jone; Galino, Jorge; Bianchi, Patrizia; Fourcade, Stéphane; Andreu, Antoni L.; Ferrer, Isidre; Muñoz-Pinedo, Cristina

    2012-01-01

    A common process associated with oxidative stress and severe mitochondrial impairment is the opening of the mitochondrial permeability transition pore, as described in many neurodegenerative diseases. Thus, inhibition of mitochondrial permeability transition pore opening represents a potential target for inhibiting mitochondrial-driven cell death. Among the mitochondrial permeability transition pore components, cyclophilin D is the most studied and has been found increased under pathological conditions. Here, we have used in vitro and in vivo models of X-linked adrenoleukodystrophy to investigate the relationship between the mitochondrial permeability transition pore opening and redox homeostasis. X-linked adrenoleukodystrophy is a neurodegenerative condition caused by loss of function of the peroxisomal ABCD1 transporter, in which oxidative stress plays a pivotal role. In this study, we provide evidence of impaired mitochondrial metabolism in a peroxisomal disease, as fibroblasts in patients with X-linked adrenoleukodystrophy cannot survive when forced to rely on mitochondrial energy production, i.e. on incubation in galactose. Oxidative stress induced under galactose conditions leads to mitochondrial damage in the form of mitochondrial inner membrane potential dissipation, ATP drop and necrotic cell death, together with increased levels of oxidative modifications in cyclophilin D protein. Moreover, we show increased expression levels of cyclophilin D in the affected zones of brains in patients with adrenomyeloneuropathy, in spinal cord of a mouse model of X-linked adrenoleukodystrophy (Abcd1-null mice) and in fibroblasts from patients with X-linked adrenoleukodystrophy. Notably, treatment with antioxidants rescues mitochondrial damage markers in fibroblasts from patients with X-linked adrenoleukodystrophy, including cyclophilin D oxidative modifications, and reverses cyclophilin D induction in vitro and in vivo. These findings provide mechanistic insight into the

  13. Catecholamine-induced cardiac mitochondrial dysfunction and mPTP opening: protective effect of curcumin.

    PubMed

    Izem-Meziane, Malika; Djerdjouri, Bahia; Rimbaud, Stephanie; Caffin, Fanny; Fortin, Dominique; Garnier, Anne; Veksler, Vladimir; Joubert, Frederic; Ventura-Clapier, Renee

    2012-02-01

    The present study was designed to characterize the mitochondrial dysfunction induced by catecholamines and to investigate whether curcumin, a natural antioxidant, induces cardioprotective effects against catecholamine-induced cardiotoxicity by preserving mitochondrial function. Because mitochondria play a central role in ischemia and oxidative stress, we hypothesized that mitochondrial dysfunction is involved in catecholamine toxicity and in the potential protective effects of curcumin. Male Wistar rats received subcutaneous injection of 150 mg·kg(-1)·day(-1) isoprenaline (ISO) for two consecutive days with or without pretreatment with 60 mg·kg(-1)·day(-1) curcumin. Twenty four hours after, cardiac tissues were examined for apoptosis and oxidative stress. Expression of proteins involved in mitochondrial biogenesis and function were measured by real-time RT-PCR. Isolated mitochondria and permeabilized cardiac fibers were used for swelling and mitochondrial function experiments, respectively. Mitochondrial morphology and permeability transition pore (mPTP) opening were assessed by fluorescence in isolated cardiomyocytes. ISO treatment induced cell damage, oxidative stress, and apoptosis that were prevented by curcumin. Moreover, mitochondria seem to play an important role in these effects as respiration and mitochondrial swelling were increased following ISO treatment, these effects being again prevented by curcumin. Importantly, curcumin completely prevented the ISO-induced increase in mPTP calcium susceptibility in isolated cardiomyocytes without affecting mitochondrial biogenesis and mitochondrial network dynamic. The results unravel the importance of mitochondrial dysfunction in isoprenaline-induced cardiotoxicity as well as a new cardioprotective effect of curcumin through prevention of mitochondrial damage and mPTP opening. PMID:22101527