Reactive oxygen species trigger Parkin/PINK1 pathway-dependent mitophagy by inducing mitochondrial recruitment of Parkin.

PubMed

Xiao, Bin; Goh, Jian-Yuan; Xiao, Lin; Xian, Hongxu; Lim, Kah-Leong; Liou, Yih-Cherng

2017-10-06

Defective mitophagy linked to dysfunction in the proteins Parkin and PTEN-induced putative kinase 1 (PINK1) is implicated in the pathogenesis of Parkinson's disease. Although the mechanism by which Parkin mediates mitophagy in a PINK1-dependent manner is becoming clearer, the triggers for this mitophagy pathway remain elusive. Reactive oxygen species (ROS) have been suggested as such triggers, but this proposal remains controversial because ROS scavengers fail to retard mitophagy. Here we demonstrate that the role of ROS in mitophagy has been underappreciated as a result of the inefficiency of ROS scavengers to control ROS bursts after high-dose treatment with carbonyl cyanide m -chlorophenylhydrazone. Supporting this, combinatorial treatment with N -acetyl-l-cysteine and catalase substantially inhibited the ROS upsurge and PINK1-dependent Parkin translocation to mitochondria in response to carbonyl cyanide m -chlorophenylhydrazone treatment. In addition to the chemical mitophagy inducer, overexpression of voltage-dependent anion channel 1 (VDAC1) induced Parkin translocation to mitochondria, presumably by stimulating ROS generation. Similarly, combined N -acetyl-l-cysteine and catalase treatment also suppressed VDAC1-induced redistribution of Parkin. Alongside these observations, we also found that the elevated protein level of PINK1 was not necessary for Parkin translocation to mitochondria. Thus, our data suggest that ROS may act as a trigger for the induction of Parkin/PINK1-dependent mitophagy. In addition, our study casts doubt on the importance of protein quantity of PINK1 in the recruitment of Parkin to mitochondria. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Ubiquitin phosphorylated at Ser57 hyper-activates parkin.

PubMed

George, Susanna; Wang, Sabrina M; Bi, Yumin; Treidlinger, Margot; Barber, Kathryn R; Shaw, Gary S; O'Donoghue, Patrick

2017-11-01

Malfunction of the ubiquitin (Ub) E3 ligase, parkin, leads to defects in mitophagy and protein quality control linked to Parkinson's disease. Parkin activity is stimulated by phosphorylation of Ub at Ser65 (pUb S65 ). Since the upstream kinase is only known for Ser65 (PINK1), the biochemical function of other phosphorylation sites on Ub remain largely unknown. We used fluorescently labelled and site-specifically phosphorylated Ub substrates to quantitatively relate the position and stoichiometry of Ub phosphorylation to parkin activation. Fluorescence measurements show that pUb S65 -stimulated parkin is 5-fold more active than auto-inhibited and un-stimulated parkin, which catalyzes a basal level of auto-ubiquitination. We consistently observed a low but detectable level of parkin activity with pUb S12 . Strikingly, pUb S57 hyper-activates parkin, and our data demonstrate that parkin is able to selectively synthesize poly-pUb S57 chains, even when 90% of the Ub in the reaction is un-phosphorylated. We further found that parkin ubiquitinates its physiological substrate Miro-1 with chains solely composed of pUb S65 and more efficiently with pUb S57 chains. Parkin hyper-activation by pUb S57 demonstrates the first PINK1-independent route to active parkin, revealing the roles of multiple ubiquitin phosphorylation sites in governing parkin stimulation and catalytic activity. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.

Parkin mediates neuroprotection through activation of Notch1 signaling.

PubMed

Yoon, Ji-Hye; Ann, Eun-Jung; Kim, Mi-Yeon; Ahn, Ji-Seon; Jo, Eun-Hye; Lee, Hye-Jin; Lee, Hye-Won; Lee, Young Chul; Kim, Jeong-Sun; Park, Hee-Sae

2017-02-04

Parkin, an E3 ubiquitin ligase, is the most frequently mutated gene in hereditary Parkinson's disease. Inactivation of Parkin leads to impairment of the ubiquitin-proteasome system, resulting in the accumulation of misfolded or aggregated proteins and ensuing neurodegeneration. In this study, we show that Parkin positively regulates the Notch1 signaling pathway. Overexpression of Parkin stabilized Notch1-IC protein levels, whereas knockdown of Parkin decreased Notch1-IC protein stability. Notably, overexpression of Parkin disrupted oxidative stress-induced apoptosis in neuronal cells. However, knockdown of Notch1 inhibited Parkin-induced neuronal cell survival. Together, these results indicate that Parkin is a novel regulator of the Notch1 signaling pathway, which promotes neuronal cell survival.

Parkin in cancer: Mitophagy-related/unrelated tasks.

PubMed

Eid, Nabil; Kondo, Yoichi

2017-03-08

Dysfunctional mitochondria may produce excessive reactive oxygen species, thus inducing DNA damage, which may be oncogenic if not repaired. As a major role of the PINK1-Parkin pathway involves selective autophagic clearance of damaged mitochondria via a process termed mitophagy, Parkin-mediated mitophagy may be a tumor-suppressive mechanism. As an alternative mechanism for tumor inhibition beyond mitophagy, Parkin has been reported to have other oncosuppressive functions such as DNA repair, negative regulation of cell proliferation and stimulation of p53 tumor suppressor function. The authors recently reported that acute ethanol-induced mitophagy in hepatocytes was associated with Parkin mitochondrial translocation and colocalization with accumulated 8-OHdG (a marker of DNA damage and mutagenicity). This finding suggests: (1) the possibility of Parkin-mediated repair of damaged mitochondrial DNA in hepatocytes of ethanol-treated rats (ETRs) as an oncosuppressive mechanism; and (2) potential induction of cytoprotective mitophagy in ETR hepatocytes if mitochondrial damage is too severe to be repaired. Below is a summary of the various roles Parkin plays in tumor suppression, which may or may not be related to mitophagy. A proper understanding of the various tasks performed by Parkin in tumorigenesis may help in cancer therapy by allowing the PINK1-Parkin pathway to be targeted.

Impulsive-compulsive behaviors in parkin-associated Parkinson disease.

PubMed

Morgante, Francesca; Fasano, Alfonso; Ginevrino, Monia; Petrucci, Simona; Ricciardi, Lucia; Bove, Francesco; Criscuolo, Chiara; Moccia, Marcello; De Rosa, Anna; Sorbera, Chiara; Bentivoglio, Anna Rita; Barone, Paolo; De Michele, Giuseppe; Pellecchia, Maria Teresa; Valente, Enza Maria

2016-10-04

The aim of this multicenter, case-control study was to investigate the prevalence and severity of impulsive-compulsive behaviors (ICBs) in a cohort of patients with parkin-associated Parkinson disease (PD) compared to a group of patients without the mutation. We compared 22 patients with biallelic parkin mutations (parkin-PD) and 26 patients negative for parkin, PINK1, DJ-1, and GBA mutations (PD-NM), matched for age at onset, disease duration, levodopa, and dopamine agonist equivalent daily dose. A semistructured interview was used to diagnose each of the following ICBs: compulsive sexual behavior, compulsive buying, binge eating, punding, hobbyism, and compulsive medication use. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) was adopted to rate ICB severity. Frequency of patients with at least one ICB was comparable between parkin-PD and PD-NM. Nevertheless, when analyzing the distribution of specific ICBs, a higher frequency of compulsive shopping, binge eating, and punding/hobbyism was found in the parkin-PD group. Compared to PD-NM, parkin-PD patients with ICB had younger onset age and higher frequency of smokers; in 5 patients, ICB had predated PD onset. Total and partial (compulsive buying, compulsive sexual behavior, binge eating, hobbyism/punding) QUIP-RS scores were higher in patients with parkin-PD compared to patients with PD-NM. Logistic regression analysis showed that the presence of parkin mutations was associated with smoking status and higher QUIP-RS total score. Our data expand the parkin-associated phenotypic spectrum demonstrating higher frequency and severity of specific ICBs, and suggesting an association between the parkin genotype, smoking status, and ICB severity. © 2016 American Academy of Neurology.

Impulsive-compulsive behaviors in parkin-associated Parkinson disease

PubMed Central

Fasano, Alfonso; Ginevrino, Monia; Petrucci, Simona; Ricciardi, Lucia; Bove, Francesco; Criscuolo, Chiara; Moccia, Marcello; De Rosa, Anna; Sorbera, Chiara; Bentivoglio, Anna Rita; Barone, Paolo; De Michele, Giuseppe; Pellecchia, Maria Teresa; Valente, Enza Maria

2016-01-01

Objective: The aim of this multicenter, case-control study was to investigate the prevalence and severity of impulsive-compulsive behaviors (ICBs) in a cohort of patients with parkin-associated Parkinson disease (PD) compared to a group of patients without the mutation. Methods: We compared 22 patients with biallelic parkin mutations (parkin-PD) and 26 patients negative for parkin, PINK1, DJ-1, and GBA mutations (PD-NM), matched for age at onset, disease duration, levodopa, and dopamine agonist equivalent daily dose. A semistructured interview was used to diagnose each of the following ICBs: compulsive sexual behavior, compulsive buying, binge eating, punding, hobbyism, and compulsive medication use. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease–Rating Scale (QUIP-RS) was adopted to rate ICB severity. Results: Frequency of patients with at least one ICB was comparable between parkin-PD and PD-NM. Nevertheless, when analyzing the distribution of specific ICBs, a higher frequency of compulsive shopping, binge eating, and punding/hobbyism was found in the parkin-PD group. Compared to PD-NM, parkin-PD patients with ICB had younger onset age and higher frequency of smokers; in 5 patients, ICB had predated PD onset. Total and partial (compulsive buying, compulsive sexual behavior, binge eating, hobbyism/punding) QUIP-RS scores were higher in patients with parkin-PD compared to patients with PD-NM. Logistic regression analysis showed that the presence of parkin mutations was associated with smoking status and higher QUIP-RS total score. Conclusions: Our data expand the parkin-associated phenotypic spectrum demonstrating higher frequency and severity of specific ICBs, and suggesting an association between the parkin genotype, smoking status, and ICB severity. PMID:27590295

Superoxide dismutating molecules rescue the toxic effects of PINK1 and parkin loss.

PubMed

Biosa, Alice; Sanchez-Martinez, Alvaro; Filograna, Roberta; Terriente-Felix, Ana; Alam, Sarah M; Beltramini, Mariano; Bubacco, Luigi; Bisaglia, Marco; Whitworth, Alexander J

2018-05-01

Reactive oxygen species exert important functions in regulating several cellular signalling pathways. However, an excessive accumulation of reactive oxygen species can perturb the redox homeostasis leading to oxidative stress, a condition which has been associated to many neurodegenerative disorders. Accordingly, alterations in the redox state of cells and mitochondrial homeostasis are established hallmarks in both familial and sporadic Parkinson's disease cases. PINK1 and Parkin are two genes which account for a large fraction of autosomal recessive early-onset forms of Parkinson's disease and are now firmly associated to both mitochondria and redox homeostasis. In this study we explored the hypothesis that superoxide anions participate in the generation of the Parkin and PINK1 associated phenotypic effect by testing the capacity of endogenous and exogenous superoxide dismutating molecules to rescue the toxic effects induced by loss of PINK1 or Parkin, in both cellular and fly models. Our results demonstrate the positive effect of an increased level of superoxide dismutase proteins on the pathological phenotypes, both in vitro and in vivo. A more pronounced effectiveness for mitochondrial SOD2 activity points to the superoxide radicals generated in the mitochondrial matrix as the prime suspect in the definition of the observed phenotypes. Moreover, we also demonstrate the efficacy of a SOD-mimetic compound, M40403, to partially ameliorate PINK1/Parkin phenotypes in vitro and in vivo. These results support the further exploration of SOD-mimetic compounds as a therapeutic strategy against Parkinson's disease.

Miro phosphorylation sites regulate Parkin recruitment and mitochondrial motility.

PubMed

Shlevkov, Evgeny; Kramer, Tal; Schapansky, Jason; LaVoie, Matthew J; Schwarz, Thomas L

2016-10-11

The PTEN-induced putative kinase 1 (PINK1)/Parkin pathway can tag damaged mitochondria and trigger their degradation by mitophagy. Before the onset of mitophagy, the pathway blocks mitochondrial motility by causing Miro degradation. PINK1 activates Parkin by phosphorylating both Parkin and ubiquitin. PINK1, however, has other mitochondrial substrates, including Miro (also called RhoT1 and -2), although the significance of those substrates is less clear. We show that mimicking PINK1 phosphorylation of Miro on S156 promoted the interaction of Parkin with Miro, stimulated Miro ubiquitination and degradation, recruited Parkin to the mitochondria, and via Parkin arrested axonal transport of mitochondria. Although Miro S156E promoted Parkin recruitment it was insufficient to trigger mitophagy in the absence of broader PINK1 action. In contrast, mimicking phosphorylation of Miro on T298/T299 inhibited PINK1-induced Miro ubiquitination, Parkin recruitment, and Parkin-dependent mitochondrial arrest. The effects of the T298E/T299E phosphomimetic were dominant over S156E substitution. We propose that the status of Miro phosphorylation influences the decision to undergo Parkin-dependent mitochondrial arrest, which, in the context of PINK1 action on other substrates, can restrict mitochondrial dynamics before mitophagy.

Miro phosphorylation sites regulate Parkin recruitment and mitochondrial motility

PubMed Central

Shlevkov, Evgeny; Kramer, Tal; Schapansky, Jason; LaVoie, Matthew J.; Schwarz, Thomas L.

2016-01-01

The PTEN-induced putative kinase 1 (PINK1)/Parkin pathway can tag damaged mitochondria and trigger their degradation by mitophagy. Before the onset of mitophagy, the pathway blocks mitochondrial motility by causing Miro degradation. PINK1 activates Parkin by phosphorylating both Parkin and ubiquitin. PINK1, however, has other mitochondrial substrates, including Miro (also called RhoT1 and -2), although the significance of those substrates is less clear. We show that mimicking PINK1 phosphorylation of Miro on S156 promoted the interaction of Parkin with Miro, stimulated Miro ubiquitination and degradation, recruited Parkin to the mitochondria, and via Parkin arrested axonal transport of mitochondria. Although Miro S156E promoted Parkin recruitment it was insufficient to trigger mitophagy in the absence of broader PINK1 action. In contrast, mimicking phosphorylation of Miro on T298/T299 inhibited PINK1-induced Miro ubiquitination, Parkin recruitment, and Parkin-dependent mitochondrial arrest. The effects of the T298E/T299E phosphomimetic were dominant over S156E substitution. We propose that the status of Miro phosphorylation influences the decision to undergo Parkin-dependent mitochondrial arrest, which, in the context of PINK1 action on other substrates, can restrict mitochondrial dynamics before mitophagy. PMID:27679849

Parkin Regulates the Activity of Pyruvate Kinase M2*

PubMed Central

Liu, Kun; Li, Fanzhou; Han, Haichao; Chen, Yue; Mao, Zebin; Luo, Jianyuan; Zhao, Yingming; Zheng, Bin; Gu, Wei; Zhao, Wenhui

2016-01-01

Parkin, a ubiquitin E3 ligase, is mutated in most cases of autosomal recessive early onset Parkinson disease. It was discovered that Parkin is also mutated in glioblastoma and other human malignancies and that it inhibits tumor cell growth. Here, we identified pyruvate kinase M2 (PKM2) as a unique substrate for parkin through biochemical purification. We found that parkin interacts with PKM2 both in vitro and in vivo, and this interaction dramatically increases during glucose starvation. Ubiquitylation of PKM2 by parkin does not affect its stability but decreases its enzymatic activity. Parkin regulates the glycolysis pathway and affects the cell metabolism. Our studies revealed the novel important roles of parkin in tumor cell metabolism and provided new insight for therapy of Parkinson disease. PMID:26975375

Phosphorylated ubiquitin chain is the genuine Parkin receptor

PubMed Central

Okatsu, Kei; Koyano, Fumika; Kimura, Mayumi; Kosako, Hidetaka; Saeki, Yasushi

2015-01-01

PINK1 selectively recruits Parkin to depolarized mitochondria for quarantine and removal of damaged mitochondria via ubiquitylation. Dysfunction of this process predisposes development of familial recessive Parkinson’s disease. Although various models for the recruitment process have been proposed, none of them adequately explain the accumulated data, and thus the molecular basis for PINK1 recruitment of Parkin remains to be fully elucidated. In this study, we show that a linear ubiquitin chain of phosphomimetic tetra-ubiquitin(S65D) recruits Parkin to energized mitochondria in the absence of PINK1, whereas a wild-type tetra-ubiquitin chain does not. Under more physiologically relevant conditions, a lysosomal phosphorylated polyubiquitin chain recruited phosphomimetic Parkin to the lysosome. A cellular ubiquitin replacement system confirmed that ubiquitin phosphorylation is indeed essential for Parkin translocation. Furthermore, physical interactions between phosphomimetic Parkin and phosphorylated polyubiquitin chain were detected by immunoprecipitation from cells and in vitro reconstitution using recombinant proteins. We thus propose that the phosphorylated ubiquitin chain functions as the genuine Parkin receptor for recruitment to depolarized mitochondria. PMID:25847540

Phosphorylation of Parkin at Serine65 is essential for activation: elaboration of a Miro1 substrate-based assay of Parkin E3 ligase activity

PubMed Central

Kazlauskaite, Agne; Kelly, Van; Johnson, Clare; Baillie, Carla; Hastie, C. James; Peggie, Mark; Macartney, Thomas; Woodroof, Helen I.; Alessi, Dario R.; Pedrioli, Patrick G. A.; Muqit, Miratul M. K.

2014-01-01

Mutations in PINK1 and Parkin are associated with early-onset Parkinson's disease. We recently discovered that PINK1 phosphorylates Parkin at serine65 (Ser65) within its Ubl domain, leading to its activation in a substrate-free activity assay. We now demonstrate the critical requirement of Ser65 phosphorylation for substrate ubiquitylation through elaboration of a novel in vitro E3 ligase activity assay using full-length untagged Parkin and its putative substrate, the mitochondrial GTPase Miro1. We observe that Parkin efficiently ubiquitylates Miro1 at highly conserved lysine residues, 153, 230, 235, 330 and 572, upon phosphorylation by PINK1. We have further established an E2-ubiquitin discharge assay to assess Parkin activity and observe robust discharge of ubiquitin-loaded UbcH7 E2 ligase upon phosphorylation of Parkin at Ser65 by wild-type, but not kinase-inactive PINK1 or a Parkin Ser65Ala mutant, suggesting a possible mechanism of how Ser65 phosphorylation may activate Parkin E3 ligase activity. For the first time, to the best of our knowledge, we report the effect of Parkin disease-associated mutations in substrate-based assays using full-length untagged recombinant Parkin. Our mutation analysis indicates an essential role for the catalytic cysteine Cys431 and reveals fundamental new knowledge on how mutations may confer pathogenicity via disruption of Miro1 ubiquitylation, free ubiquitin chain formation or by impacting Parkin's ability to discharge ubiquitin from a loaded E2. This study provides further evidence that phosphorylation of Parkin at Ser65 is critical for its activation. It also provides evidence that Miro1 is a direct Parkin substrate. The assays and reagents developed in this study will be important to uncover new insights into Parkin biology as well as aid in the development of screens to identify small molecule Parkin activators for the treatment of Parkinson's disease. PMID:24647965

Parkin Regulates the Activity of Pyruvate Kinase M2.

PubMed

Liu, Kun; Li, Fanzhou; Han, Haichao; Chen, Yue; Mao, Zebin; Luo, Jianyuan; Zhao, Yingming; Zheng, Bin; Gu, Wei; Zhao, Wenhui

2016-05-06

Parkin, a ubiquitin E3 ligase, is mutated in most cases of autosomal recessive early onset Parkinson disease. It was discovered that Parkin is also mutated in glioblastoma and other human malignancies and that it inhibits tumor cell growth. Here, we identified pyruvate kinase M2 (PKM2) as a unique substrate for parkin through biochemical purification. We found that parkin interacts with PKM2 both in vitro and in vivo, and this interaction dramatically increases during glucose starvation. Ubiquitylation of PKM2 by parkin does not affect its stability but decreases its enzymatic activity. Parkin regulates the glycolysis pathway and affects the cell metabolism. Our studies revealed the novel important roles of parkin in tumor cell metabolism and provided new insight for therapy of Parkinson disease. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Association of murine lupus and thymic full-length endogenous retroviral expression maps to a bone marrow stem cell

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

Krieg, A.M.; Gourley, M.F.; Steinberg, A.D.

1991-05-01

Recent studies of thymic gene expression in murine lupus have demonstrated 8.4-kb (full-length size) modified polytropic (Mpmv) endogenous retroviral RNA. In contrast, normal control mouse strains do not produce detectable amounts of such RNA in their thymuses. Prior studies have attributed a defect in experimental tolerance in murine lupus to a bone marrow stem cell rather than to the thymic epithelium; in contrast, infectious retroviral expression has been associated with the thymic epithelium, rather than with the bone marrow stem cell. The present study was designed to determine whether the abnormal Mpmv expression associated with murine lupus mapped to thymicmore » epithelium or to a marrow precursor. Lethally irradiated control and lupus-prone mice were reconstituted with T cell depleted bone marrow; one month later their thymuses were studied for endogenous retroviral RNA and protein expression. Recipients of bone marrow from nonautoimmune donors expressed neither 8.4-kb Mpmv RNA nor surface MCF gp70 in their thymuses. In contrast, recipients of bone marrow from autoimmune NZB or BXSB donors expressed thymic 8.4-kb Mpmv RNA and mink cell focus-forming gp70. These studies demonstrate that lupus-associated 8.4-kb Mpmv endogenous retroviral expression is determined by bone marrow stem cells.« less

Dual Function of Phosphoubiquitin in E3 Activation of Parkin*

PubMed Central

Walinda, Erik; Morimoto, Daichi; Sugase, Kenji; Shirakawa, Masahiro

2016-01-01

Mutations in the gene encoding parkin, an auto-inhibited E3 ubiquitin ligase that functions in the clearance of damaged mitochondria, are the most common cause of autosomal recessive juvenile Parkinsonism. The mechanism regulating parkin activation remains poorly understood. Here we show, by using isothermal titration calorimetry, solution NMR, and fluorescence spectroscopy, that parkin can bind ubiquitin and phosphomimetic ubiquitin by recognizing the canonical hydrophobic patch and C terminus of ubiquitin. The affinity of parkin for both phosphomimetic and unmodified ubiquitin is markedly enhanced upon removal of the ubiquitin-like (UBL) domain of parkin. This suggests that the agonistic binding of ubiquitin to parkin in trans is counterbalanced by the antagonistic activity of the parkin UBL domain in cis. Intriguingly, UBL binding is enthalpy-driven, whereas ubiquitin binding is driven by an increase in the total entropy of the system. These thermodynamic differences are explained by different chemistry in the ubiquitin- and UBL-binding pockets of parkin and, as shown by molecular dynamics simulations, are not a consequence of changes in protein conformational entropy. Indeed, comparison of conformational fluctuations reveals that the RING1-IBR element becomes considerably more rigid upon complex formation. A model of parkin activation is proposed in which E2∼Ub binding triggers large scale diffusional motion of the RING2 domain toward the ubiquitin-stabilized RING1-IBR assembly to complete formation of the active parkin-E2∼Ub transfer complex. Thus, ubiquitin plays a dual role in parkin activation by competing with the inhibitory UBL domain and stabilizing the active form of parkin. PMID:27284007

Pathologic and Therapeutic Implications for the Cell Biology of Parkin

PubMed Central

Charan, Rakshita A.; LaVoie, Matthew J.

2015-01-01

Mutations in the E3 ligase parkin are the most common cause of autosomal recessive Parkinson's disease (PD), but it is believed that parkin dysfunction may also contribute to idiopathic PD. Since its discovery, parkin has been implicated in supporting multiple neuroprotective pathways, many revolving around the maintenance of mitochondrial health quality control and governance of cell survival. Recent advances across the structure, biochemistry, and cell biology of parkin have provided great insights into the etiology of parkin-linked and idiopathic PD and may ultimately generate novel therapeutic strategies to slow or halt disease progression. This review describes the various pathways in which parkin acts and the mechanisms by which parkin may be targeted for therapeutic intervention. PMID:25697646

Dual Function of Phosphoubiquitin in E3 Activation of Parkin.

PubMed

Walinda, Erik; Morimoto, Daichi; Sugase, Kenji; Shirakawa, Masahiro

2016-08-05

Mutations in the gene encoding parkin, an auto-inhibited E3 ubiquitin ligase that functions in the clearance of damaged mitochondria, are the most common cause of autosomal recessive juvenile Parkinsonism. The mechanism regulating parkin activation remains poorly understood. Here we show, by using isothermal titration calorimetry, solution NMR, and fluorescence spectroscopy, that parkin can bind ubiquitin and phosphomimetic ubiquitin by recognizing the canonical hydrophobic patch and C terminus of ubiquitin. The affinity of parkin for both phosphomimetic and unmodified ubiquitin is markedly enhanced upon removal of the ubiquitin-like (UBL) domain of parkin. This suggests that the agonistic binding of ubiquitin to parkin in trans is counterbalanced by the antagonistic activity of the parkin UBL domain in cis Intriguingly, UBL binding is enthalpy-driven, whereas ubiquitin binding is driven by an increase in the total entropy of the system. These thermodynamic differences are explained by different chemistry in the ubiquitin- and UBL-binding pockets of parkin and, as shown by molecular dynamics simulations, are not a consequence of changes in protein conformational entropy. Indeed, comparison of conformational fluctuations reveals that the RING1-IBR element becomes considerably more rigid upon complex formation. A model of parkin activation is proposed in which E2∼Ub binding triggers large scale diffusional motion of the RING2 domain toward the ubiquitin-stabilized RING1-IBR assembly to complete formation of the active parkin-E2∼Ub transfer complex. Thus, ubiquitin plays a dual role in parkin activation by competing with the inhibitory UBL domain and stabilizing the active form of parkin. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Quantitative proteomic analysis of Parkin substrates in Drosophila neurons.

PubMed

Martinez, Aitor; Lectez, Benoit; Ramirez, Juanma; Popp, Oliver; Sutherland, James D; Urbé, Sylvie; Dittmar, Gunnar; Clague, Michael J; Mayor, Ugo

2017-04-11

Parkin (PARK2) is an E3 ubiquitin ligase that is commonly mutated in Familial Parkinson's Disease (PD). In cell culture models, Parkin is recruited to acutely depolarised mitochondria by PINK1. PINK1 activates Parkin activity leading to ubiquitination of multiple proteins, which in turn promotes clearance of mitochondria by mitophagy. Many substrates have been identified using cell culture models in combination with depolarising drugs or proteasome inhibitors, but not in more physiological settings. Here we utilized the recently introduced BioUb strategy to isolate ubiquitinated proteins in flies. Following Parkin Wild-Type (WT) and Parkin Ligase dead (LD) expression we analysed by mass spectrometry and stringent bioinformatics analysis those proteins differentially ubiquitinated to provide the first survey of steady state Parkin substrates using an in vivo model. We further used an in vivo ubiquitination assay to validate one of those substrates in SH-SY5Y cells. We identified 35 proteins that are more prominently ubiquitinated following Parkin over-expression. These include several mitochondrial proteins and a number of endosomal trafficking regulators such as v-ATPase sub-units, Syx5/STX5, ALiX/PDCD6IP and Vps4. We also identified the retromer component, Vps35, another PD-associated gene that has recently been shown to interact genetically with parkin. Importantly, we validated Parkin-dependent ubiquitination of VPS35 in human neuroblastoma cells. Collectively our results provide new leads to the possible physiological functions of Parkin activity that are not overtly biased by acute mitochondrial depolarisation.

Parkin regulation of CHOP modulates susceptibility to cardiac endoplasmic reticulum stress.

PubMed

Han, Kim; Hassanzadeh, Shahin; Singh, Komudi; Menazza, Sara; Nguyen, Tiffany T; Stevens, Mark V; Nguyen, An; San, Hong; Anderson, Stasia A; Lin, Yongshun; Zou, Jizhong; Murphy, Elizabeth; Sack, Michael N

2017-05-18

The regulatory control of cardiac endoplasmic reticulum (ER) stress is incompletely characterized. As ER stress signaling upregulates the E3-ubiquitin ligase Parkin, we investigated the role of Parkin in cardiac ER stress. Parkin knockout mice exposed to aortic constriction-induced cardiac pressure-overload or in response to systemic tunicamycin (TM) developed adverse ventricular remodeling with excessive levels of the ER regulatory C/EBP homologous protein CHOP. CHOP was identified as a Parkin substrate and its turnover was Parkin-dose and proteasome-dependent. Parkin depletion in cardiac HL-1 cells increased CHOP levels and enhanced susceptibility to TM-induced cell death. Parkin reconstitution rescued this phenotype and the contribution of excess CHOP to this ER stress injury was confirmed by reduction in TM-induced cell death when CHOP was depleted in Parkin knockdown cardiomyocytes. Isogenic Parkin mutant iPSC-derived cardiomyocytes showed exaggerated ER stress induced CHOP and apoptotic signatures and myocardium from subjects with dilated cardiomyopathy showed excessive Parkin and CHOP induction. This study identifies that Parkin functions to blunt excessive CHOP to prevent maladaptive ER stress-induced cell death and adverse cardiac ventricular remodeling. Additionally, Parkin is identified as a novel post-translational regulatory moderator of CHOP stability and uncovers an additional stress-modifying function of this E3-ubiquitin ligase.

Structure-guided mutagenesis reveals a hierarchical mechanism of Parkin activation

PubMed Central

Tang, Matthew Y.; Vranas, Marta; Krahn, Andrea I.; Pundlik, Shayal; Trempe, Jean- François; Fon, Edward A.

2017-01-01

Parkin and PINK1 function in a common pathway to clear damaged mitochondria. Parkin exists in an auto-inhibited conformation stabilized by multiple interdomain interactions. The binding of PINK1-generated phospho-ubiquitin and the phosphorylation of the ubiquitin-like (Ubl) domain of Parkin at Ser65 release its auto-inhibition, but how and when these events take place in cells remain to be defined. Here we show that mutations that we designed to activate Parkin by releasing the Repressor Element of Parkin (REP) domain, or by disrupting the interface between the RING0:RING2 domains, can completely rescue mutations in the Parkin Ubl that are defective in mitochondrial autophagy. Using a FRET reporter assay we show that Parkin undergoes a conformational change upon phosphorylation that can be mimicked by mutating Trp403 in the REP. We propose a hierarchical model whereby pUb binding on mitochondria enables Parkin phosphorylation, which, in turn, leads to REP removal, E3 ligase activation and mitophagy. PMID:28276439

Structure-guided mutagenesis reveals a hierarchical mechanism of Parkin activation.

PubMed

Tang, Matthew Y; Vranas, Marta; Krahn, Andrea I; Pundlik, Shayal; Trempe, Jean-François; Fon, Edward A

2017-03-09

Parkin and PINK1 function in a common pathway to clear damaged mitochondria. Parkin exists in an auto-inhibited conformation stabilized by multiple interdomain interactions. The binding of PINK1-generated phospho-ubiquitin and the phosphorylation of the ubiquitin-like (Ubl) domain of Parkin at Ser65 release its auto-inhibition, but how and when these events take place in cells remain to be defined. Here we show that mutations that we designed to activate Parkin by releasing the Repressor Element of Parkin (REP) domain, or by disrupting the interface between the RING0:RING2 domains, can completely rescue mutations in the Parkin Ubl that are defective in mitochondrial autophagy. Using a FRET reporter assay we show that Parkin undergoes a conformational change upon phosphorylation that can be mimicked by mutating Trp403 in the REP. We propose a hierarchical model whereby pUb binding on mitochondria enables Parkin phosphorylation, which, in turn, leads to REP removal, E3 ligase activation and mitophagy.

Identification and molecular characterization of Parkin in Clonorchis sinensis.

PubMed

Bai, Xuelian; Kim, Tae Im; Lee, Ji-Yun; Dai, Fuhong; Hong, Sung-Jong

2015-02-01

Clonorchis sinensis habitating in the bile duct of mammals causes clonorchiasis endemic in East Asian countries. Parkin is a RING-between-RING protein and has E3-ubiquitin ligase activity catalyzing ubiquitination and degradation of substrate proteins. A cDNA clone of C. sinensis was predicted to encode a polypeptide homologous to parkin (CsParkin) including 5 domains (Ubl, RING0, RING1, IBR, and RING2). The cysteine and histidine residues binding to Zn(2+) were all conserved and participated in formation of tertiary structural RINGs. Conserved residues were also an E2-binding site in RING1 domain and a catalytic cysteine residue in the RING2 domain. Native CsParkin was determined to have an estimated molecular weight of 45.7 kDa from C. sinensis adults by immunoblotting. CsParkin revealed E3-ubiquitin ligase activity and higher expression in metacercariae than in adults. CsParkin was localized in the locomotive and male reproductive organs of C. sinensis adults, and extensively in metacercariae. Parkin has been found to participate in regulating mitochondrial function and energy metabolism in mammalian cells. From these results, it is suggested that CsParkin play roles in energy metabolism of the locomotive organs, and possibly in protein metabolism of the reproductive organs of C. sinensis.

Autoregulation of Parkin activity through its ubiquitin-like domain

PubMed Central

Chaugule, Viduth K; Burchell, Lynn; Barber, Kathryn R; Sidhu, Ateesh; Leslie, Simon J; Shaw, Gary S; Walden, Helen

2011-01-01

Parkin is an E3-ubiquitin ligase belonging to the RBR (RING–InBetweenRING–RING family), and is involved in the neurodegenerative disorder Parkinson's disease. Autosomal recessive juvenile Parkinsonism, which is one of the most common familial forms of the disease, is directly linked to mutations in the parkin gene. However, the molecular mechanisms of Parkin dysfunction in the disease state remain to be established. We now demonstrate that the ubiquitin-like domain of Parkin functions to inhibit its autoubiquitination. Moreover pathogenic Parkin mutations disrupt this autoinhibition, resulting in a constitutively active molecule. In addition, we show that the mechanism of autoregulation involves ubiquitin binding by a C-terminal region of Parkin. Our observations provide important molecular insights into the underlying basis of Parkinson's disease, and in the regulation of RBR E3-ligase activity. PMID:21694720

Phosphorylation of Mitochondrial Polyubiquitin by PINK1 Promotes Parkin Mitochondrial Tethering

PubMed Central

Shiba-Fukushima, Kahori; Arano, Taku; Matsumoto, Gen; Inoshita, Tsuyoshi; Yoshida, Shigeharu; Ishihama, Yasushi; Ryu, Kwon-Yul; Nukina, Nobuyuki; Hattori, Nobutaka; Imai, Yuzuru

2014-01-01

The kinase PINK1 and the E3 ubiquitin (Ub) ligase Parkin participate in mitochondrial quality control. The phosphorylation of Ser65 in Parkin's ubiquitin-like (UBl) domain by PINK1 stimulates Parkin activation and translocation to damaged mitochondria, which induces mitophagy generating polyUb chain. However, Parkin Ser65 phosphorylation is insufficient for Parkin mitochondrial translocation. Here we report that Ser65 in polyUb chain is also phosphorylated by PINK1, and that phosphorylated polyUb chain on mitochondria tethers Parkin at mitochondria. The expression of Tom70MTS-4xUb SE, which mimics phospho-Ser65 polyUb chains on the mitochondria, activated Parkin E3 activity and its mitochondrial translocation. An E3-dead form of Parkin translocated to mitochondria with reduced membrane potential in the presence of Tom70MTS-4xUb SE, whereas non-phospho-polyUb mutant Tom70MTS-4xUb SA abrogated Parkin translocation. Parkin binds to the phospho-polyUb chain through its RING1-In-Between-RING (IBR) domains, but its RING0-linker is also required for mitochondrial translocation. Moreover, the expression of Tom70MTS-4xUb SE improved mitochondrial degeneration in PINK1-deficient, but not Parkin-deficient, Drosophila. Our study suggests that the phosphorylation of mitochondrial polyUb by PINK1 is implicated in both Parkin activation and mitochondrial translocation, predicting a chain reaction mechanism of mitochondrial phospho-polyUb production by which rapid translocation of Parkin is achieved. PMID:25474007

Parkin promotes proteasomal degradation of synaptotagmin IV by accelerating polyubiquitination.

PubMed

Kabayama, Hiroyuki; Tokushige, Naoko; Takeuchi, Makoto; Kabayama, Miyuki; Fukuda, Mitsunori; Mikoshiba, Katsuhiko

2017-04-01

Parkin is an E3 ubiquitin ligase whose mutations cause autosomal recessive juvenile Parkinson's disease (PD). Unlike the human phenotype, parkin knockout (KO) mice show no apparent dopamine neuron degeneration, although they demonstrate reduced expression and activity of striatal mitochondrial proteins believed to be necessary for neuronal survival. Instead, parkin-KO mice show reduced striatal evoked dopamine release, abnormal synaptic plasticity, and non-motor symptoms, all of which appear to mimic the preclinical features of Parkinson's disease. Extensive studies have screened candidate synaptic proteins responsible for reduced evoked dopamine release, and synaptotagmin XI (Syt XI), an isoform of Syt family regulating membrane trafficking, has been identified as a substrate of parkin in humans. However, its expression level is unaltered in the striatum of parkin-KO mice. Thus, the target(s) of parkin and the molecular mechanisms underlying the impaired dopamine release in parkin-KO mice remain unknown. In this study, we focused on Syt IV because of its highly homology to Syt XI, and because they share an evolutionarily conserved lack of Ca 2+ -binding capacity; thus, Syt IV plays an inhibitory role in Ca 2+ -dependent neurotransmitter release in PC12 cells and neurons in various brain regions. We found that a proteasome inhibitor increased Syt IV protein, but not Syt XI protein, in neuron-like, differentiated PC12 cells, and that parkin interacted with and polyubiquitinated Syt IV, thereby accelerating its protein turnover. Parkin overexpression selectively degraded Syt IV protein, but not Syt I protein (indispensable for Ca 2+ -dependent exocytosis), thus enhancing depolarization-dependent exocytosis. Furthermore, in parkin-KO mice, the level of striatal Syt IV protein was increased. Our data indicate a crucial role for parkin in the proteasomal degradation of Syt IV, and provide a potential mechanism of parkin-regulated, evoked neurotransmitter release

Molecular dynamics simulations of human E3 ubiquitin ligase Parkin

PubMed Central

Qiu, Shi; Zhu, Shun; Xu, Shan; Han, Yanyan; Liu, Wen; Zuo, Ji

2017-01-01

Human E3 ubiquitin protein ligase parkin (Parkin) mediates mitophagy to maintain mitochondrial homeostasis. Parkin mutations are common genetic causes of early onset familial Parkinson's disease. The molecular mechanism of Parkin activation has been widely studied with emerging evidence suggesting an essential role of the phosphorylated (phospho)-ubiquitin interaction. However, the underlying mechanism of the phospho-ubiquitin interaction remains elusive. In the present study, replica exchange molecular dynamics simulations were performed to examine the conformational dynamics of Parkin in monomer and phospho-ubiquitin-bound states. In the Parkin monomer state, high structural flexibilities were observed in the majority of regions of Parkin particularly in the loop domain between the ubiquitin-like (UBL) and really interesting new gene (RING)0 domain. Binding of phospho-ubiquitin stabilizes the RING1/RING in between RING interface but destabilizes the RING1-UBL interface. Furthermore, using steered molecular dynamics simulations of Parkin mutations, it was demonstrated that salt bridge interactions contribute significantly to the interdomain interactions between the RING1 and UBL domain. Taken together, the results of the present study revealed the conformational dynamics of human full-length Parkin in monomer and phospho-ubiquitin-bound states, providing insights into designing potential therapeutics against Parkinson's disease. PMID:28765939

Molecular dynamics simulations of human E3 ubiquitin ligase Parkin.

PubMed

Qiu, Shi; Zhu, Shun; Xu, Shan; Han, Yanyan; Liu, Wen; Zuo, Ji

2017-10-01

Human E3 ubiquitin protein ligase parkin (Parkin) mediates mitophagy to maintain mitochondrial homeostasis. Parkin mutations are common genetic causes of early onset familial Parkinson's disease. The molecular mechanism of Parkin activation has been widely studied with emerging evidence suggesting an essential role of the phosphorylated (phospho)‑ubiquitin interaction. However, the underlying mecha-nism of the phospho‑ubiquitin interaction remains elusive. In the present study, replica exchange molecular dynamics simulations were performed to examine the conformational dynamics of Parkin in monomer and phospho‑ubiquitin‑bound states. In the Parkin monomer state, high structural flexi-bilities were observed in the majority of regions of Parkin particularly in the loop domain between the ubiquitin‑like (UBL) and really interesting new gene (RING)0 domain. Binding of phospho‑ubiquitin stabilizes the RING1/RING in between RING interface but destabilizes the RING1‑UBL interface. Furthermore, using steered molecular dynamics simulations of Parkin mutations, it was demonstrated that salt bridge interactions contribute significantly to the interdomain interactions between the RING1 and UBL domain. Taken together, the results of the present study revealed the conformational dynamics of human full‑length Parkin in monomer and phospho‑ubiquitin‑bound states, providing insights into designing potential therapeutics against Parkinson's disease.

Parkin-mediated mitophagy is downregulated in browning of white adipose tissue.

PubMed

Taylor, David; Gottlieb, Roberta A

2017-04-01

Browning of white adipose tissue (WAT) promotes increased energy expenditure through the action of uncoupling protein 1 (UCP1) and is an attractive target to promote weight loss in obesity. Lowering of mitochondrial membrane potential by UCP1 is uniquely beneficial in this context; in other tissues, reduced membrane potential promotes mitochondrial clearance via mitophagy. It is unknown how parkin-mediated mitophagy is regulated in beige adipocytes. The relationship between parkin expression and WAT browning was investigated in 3T3-L1 adipocytes and parkin-deficient male C57BL/6 mice in response to pharmacological browning stimuli. Rosiglitazone treatment in 3T3-L1 adipocytes promoted mitochondrial biogenesis, UCP1 expression, and mitochondrial uncoupling. Parkin expression was decreased and reduced mitochondrial-associated parkin, and p62 indicated a reduction in mitophagy activity. Parkin overexpression prevented mitochondrial remodeling in response to rosiglitazone. In CL 316,243-treated wild-type mice, decreased parkin expression was observed in subcutaneous inguinal WAT, where UCP1 was strongly induced. CL 316,243 treatment weakly induced UCP1 expression in the gonadal depot, where parkin expression was unchanged. In contrast, parkin-deficient mice exhibited robust UCP1 expression in gonadal WAT following CL 316,243 treatment. WAT browning was associated with a decrease in parkin-mediated mitophagy, and parkin expression antagonized browning of WAT. © 2017 The Obesity Society.

Parkin absence accelerates microtubule aging in dopaminergic neurons.

PubMed

Cartelli, Daniele; Amadeo, Alida; Calogero, Alessandra Maria; Casagrande, Francesca Vittoria Marialuisa; De Gregorio, Carmelita; Gioria, Mariarosa; Kuzumaki, Naoko; Costa, Ilaria; Sassone, Jenny; Ciammola, Andrea; Hattori, Nobutaka; Okano, Hideyuki; Goldwurm, Stefano; Roybon, Laurent; Pezzoli, Gianni; Cappelletti, Graziella

2018-01-01

Loss-of-function caused by mutations in the parkin gene (PARK2) lead to early-onset familial Parkinson's disease. Recently, mechanistic studies proved the ability of parkin in regulating mitochondria homeostasis and microtubule (MT) stability. Looking at these systems during aging of PARK2 knockout mice, we found that loss of parkin induced an accelerated (over)acetylation of MT system both in dopaminergic neuron cell bodies and fibers, localized in the substantia nigra and corpus striatum, respectively. Interestingly, in PARK2 knockout mice, changes of MT stability preceded the alteration of mitochondria transport. Moreover, in-cell experiments confirmed that loss of parkin affects mitochondria mobility and showed that this defect depends on MT system as it is rescued by paclitaxel, a well-known MT-targeted agent. Furthermore, both in PC12 neuronal cells and in patients' induced pluripotent stem cell-derived midbrain neurons, we observed that parkin deficiencies cause the fragmentation of stable MTs. Therefore, we suggest that parkin acts as a regulator of MT system during neuronal aging, and we endorse the hypothesis that MT dysfunction may be crucial in the pathogenesis of Parkinson's disease. Copyright © 2017 Elsevier Inc. All rights reserved.

Regulation of parkin and PINK1 by neddylation

PubMed Central

Choo, Yeun Su; Vogler, Georg; Wang, Danling; Kalvakuri, Sreehari; Iliuk, Anton; Tao, W. Andy; Bodmer, Rolf; Zhang, Zhuohua

2012-01-01

Neddylation is a posttranslational modification that plays important roles in regulating protein structure and function by covalently conjugating NEDD8, an ubiquitin-like small molecule, to the substrate. Here, we report that Parkinson's disease (PD)-related parkin and PINK1 are NEDD8 conjugated. Neddylation of parkin and PINK1 results in increased E3 ligase activity of parkin and selective stabilization of the 55 kDa PINK1 fragment. Expression of dAPP-BP1, a NEDD8 activation enzyme subunit, in Drosophila suppresses abnormalities induced by dPINK1 RNAi. PD neurotoxin MPP+ inhibits neddylation of both parkin and PINK1. NEDD8 immunoreactivity is associated with Lewy bodies in midbrain dopaminergic neurons of PD patients. Together, these results suggest that parkin and PINK1 are regulated by neddylation and that impaired NEDD8 modification of these proteins likely contributes to PD pathogenesis. PMID:22388932

Parkin regulates translesion DNA synthesis in response to UV radiation.

PubMed

Zhu, Xuefei; Ma, Xiaolu; Tu, Yingfeng; Huang, Min; Liu, Hongmei; Wang, Fengli; Gong, Juanjuan; Wang, Jiuqiang; Li, Xiaoling; Chen, Qian; Shen, Hongyan; Zhu, Shu; Wang, Yun; Liu, Yang; Guo, Caixia; Tang, Tie-Shan

2017-05-30

Deficiency of Parkin is a major cause of early-onset Parkinson's disease (PD). Notably, PD patients also exhibit a significantly higher risk in melanoma and other skin tumors, while the mechanism remains largely unknown. In this study, we show that depletion of Parkin causes compromised cell viability and genome stability after ultraviolet (UV) radiation. We demonstrate that Parkin promotes efficient Rad18-dependent proliferating cell nuclear antigen (PCNA) monoubiquitination by facilitating the formation of Replication protein A (RPA)-coated ssDNA upon UV radiation. Furthermore, Parkin is found to physically interact with NBS1 (Nijmegen breakage syndrome 1), and to be required for optimal recruitment of NBS1 and DNA polymerase eta (Polη) to UV-induced damage sites. Consequently, depletion of Parkin leads to increased UV-induced mutagenesis. These findings unveil an important role of Parkin in protecting genome stability through positively regulating translesion DNA synthesis (TLS) upon UV damage, providing a novel mechanistic link between Parkin deficiency and predisposition to skin cancers in PD patients.

MUL1 acts in parallel to the PINK1/parkin pathway in regulating mitofusin and compensates for loss of PINK1/parkin

PubMed Central

Yun, Jina; Puri, Rajat; Yang, Huan; Lizzio, Michael A; Wu, Chunlai; Sheng, Zu-Hang; Guo, Ming

2014-01-01

Parkinson's disease (PD) genes PINK1 and parkin act in a common pathway that regulates mitochondrial integrity and quality. Identifying new suppressors of the pathway is important for finding new therapeutic strategies. In this study, we show that MUL1 suppresses PINK1 or parkin mutant phenotypes in Drosophila. The suppression is achieved through the ubiquitin-dependent degradation of Mitofusin, which itself causes PINK1/parkin mutant-like toxicity when overexpressed. We further show that removing MUL1 in PINK1 or parkin loss-of-function mutant aggravates phenotypes caused by loss of either gene alone, leading to lethality in flies and degeneration in mouse cortical neurons. Together, these observations show that MUL1 acts in parallel to the PINK1/parkin pathway on a shared target mitofusin to maintain mitochondrial integrity. The MUL1 pathway compensates for loss of PINK1/parkin in both Drosophila and mammals and is a promising therapeutic target for PD. DOI: http://dx.doi.org/10.7554/eLife.01958.001 PMID:24898855

Parkin gene alterations in ovarian carcinoma from northern Indian population.

PubMed

Mehdi, Syed Jafar; Ali, Asgar; Rizvi, M Moshahid Alam

2011-09-01

Parkin, a tumor suppressor gene located on chromosome 6q25-27, has been identified as a target for mutation in many human malignancies like breast, ovaries, cervical and lungs etc. After a preliminary report on the loss of heterozygosity and altered Parkin expression in breast and ovarian tumors, we aimed to study loss of heterozygosity in the Parkin gene associated microsatellite markers and its expression in human ovarian cancer patients from Indian population. We examined 102 paired normal and ovarian cancer samples for allelic loss in Parkin gene locus using Parkin gene associated microsatellite markers through loss of heterozygosity and changes in its expression through semiquantitative RT-PCR. Loss of heterozygosity identified common region of loss in Parkin locus with highest frequency for the intragenic marker D6S1599 (53%) whereas, 49 of 102 (48%) specimens showed decreased or no expression of Parkin in ovarian tumors. The study revealed that presence of loss of heterozygosity was significantly higher in both the intragenic markers (D6S1599 and D6S305) as compared with the locus of flanking region (D6S1008) with their p value 0.000001 and 0.00008, respectively. It also revealed that Parkin inactivation is probably a combination of loss of heterozygosity coupled with downregulation of Parkin gene through an alternative means like epigenetic mechanism. These data strongly supports the previous study and argue that Parkin is a tumor suppressor gene whose inactivation may play an important role in ovarian carcinoma.

Overexpression of parkin in rat nigrostriatal dopamine system protects against methamphetamine neurotoxicity

PubMed Central

Liu, Bin; Traini, Roberta; Killinger, Bryan; Schneider, Bernard; Moszczynska, Anna

2013-01-01

Methamphetamine (METH) is a central nervous system psychostimulant with a high potential for abuse. At high doses, METH causes a selective degeneration of dopaminergic terminals in the striatum, sparing other striatal terminals and cell bodies. We previously detected a deficit in parkin after binge METH in rat striatal synaptosomes. Parkin is an ubiquitin-protein E3 ligase capable of protecting dopamine neurons from diverse cellular insults. Whether the deficit in parkin mediates the toxicity of METH and whether parkin can protect from toxicity of the drug is unknown. The present study investigated whether overexpression of parkin attenuates degeneration of striatal dopaminergic terminals exposed to binge METH. Parkin overexpression in rat nigrostriatal dopamine system was achieved by microinjection of adeno-associated viral transfer vector 2/6 encoding rat parkin (AAV2/6-parkin) into the substantia nigra pars compacta. The microinjections of AAV2/6-parkin dose-dependently increased parkin levels in both the substantia nigra pars compacta and striatum. The levels of dopamine synthesizing enzyme, tyrosine hydroxylase, remained at the control levels; therefore, tyrosine hydroxylase immunoreactivity was used as an index of dopaminergic terminal integrity. In METH-exposed rats, the increase in parkin levels attenuated METH-induced decreases in striatal tyrosine hydroxylase immunoreactivity in a dose-dependent manner, indicating that parkin can protect striatal dopaminergic terminals against METH neurotoxicity. PMID:23313192

Landscape of the PARKIN-dependent ubiquitylome in response to mitochondrial depolarization.

PubMed

Sarraf, Shireen A; Raman, Malavika; Guarani-Pereira, Virginia; Sowa, Mathew E; Huttlin, Edward L; Gygi, Steven P; Harper, J Wade

2013-04-18

The PARKIN ubiquitin ligase (also known as PARK2) and its regulatory kinase PINK1 (also known as PARK6), often mutated in familial early-onset Parkinson's disease, have central roles in mitochondrial homeostasis and mitophagy. Whereas PARKIN is recruited to the mitochondrial outer membrane (MOM) upon depolarization via PINK1 action and can ubiquitylate porin, mitofusin and Miro proteins on the MOM, the full repertoire of PARKIN substrates--the PARKIN-dependent ubiquitylome--remains poorly defined. Here we use quantitative diGly capture proteomics (diGly) to elucidate the ubiquitylation site specificity and topology of PARKIN-dependent target modification in response to mitochondrial depolarization. Hundreds of dynamically regulated ubiquitylation sites in dozens of proteins were identified, with strong enrichment for MOM proteins, indicating that PARKIN dramatically alters the ubiquitylation status of the mitochondrial proteome. Using complementary interaction proteomics, we found depolarization-dependent PARKIN association with numerous MOM targets, autophagy receptors, and the proteasome. Mutation of the PARKIN active site residue C431, which has been found mutated in Parkinson's disease patients, largely disrupts these associations. Structural and topological analysis revealed extensive conservation of PARKIN-dependent ubiquitylation sites on cytoplasmic domains in vertebrate and Drosophila melanogaster MOM proteins. These studies provide a resource for understanding how the PINK1-PARKIN pathway re-sculpts the proteome to support mitochondrial homeostasis.

Parkin regulates translesion DNA synthesis in response to UV radiation

PubMed Central

Huang, Min; Liu, Hongmei; Wang, Fengli; Gong, Juanjuan; Wang, Jiuqiang; Li, Xiaoling; Chen, Qian; Shen, Hongyan; Zhu, Shu; Wang, Yun; Liu, Yang; Guo, Caixia; Tang, Tie-Shan

2017-01-01

Deficiency of Parkin is a major cause of early-onset Parkinson's disease (PD). Notably, PD patients also exhibit a significantly higher risk in melanoma and other skin tumors, while the mechanism remains largely unknown. In this study, we show that depletion of Parkin causes compromised cell viability and genome stability after ultraviolet (UV) radiation. We demonstrate that Parkin promotes efficient Rad18-dependent proliferating cell nuclear antigen (PCNA) monoubiquitination by facilitating the formation of Replication protein A (RPA)-coated ssDNA upon UV radiation. Furthermore, Parkin is found to physically interact with NBS1 (Nijmegen breakage syndrome 1), and to be required for optimal recruitment of NBS1 and DNA polymerase eta (Polη) to UV-induced damage sites. Consequently, depletion of Parkin leads to increased UV-induced mutagenesis. These findings unveil an important role of Parkin in protecting genome stability through positively regulating translesion DNA synthesis (TLS) upon UV damage, providing a novel mechanistic link between Parkin deficiency and predisposition to skin cancers in PD patients. PMID:28430587

Parkin Deficiency Reduces Hippocampal Glutamatergic Neurotransmission by Impairing AMPA Receptor Endocytosis.

PubMed

Cortese, Giuseppe P; Zhu, Mei; Williams, Damian; Heath, Sarah; Waites, Clarissa L

2016-11-30

Mutations in the gene encoding Parkin, an E3 ubiquitin ligase, lead to juvenile-onset Parkinson's disease by inducing the selective death of midbrain dopaminergic neurons. Accumulating evidence indicates that Parkin also has an important role in excitatory glutamatergic neurotransmission, although its precise mechanism of action remains unclear. Here, we investigate Parkin's role at glutamatergic synapses of rat hippocampal neurons. We find that Parkin-deficient neurons exhibit significantly reduced AMPA receptor (AMPAR)-mediated currents and cell-surface expression, and that these phenotypes result from decreased postsynaptic expression of the adaptor protein Homer1, which is necessary for coupling AMPAR endocytic zones with the postsynaptic density. Accordingly, Parkin loss of function leads to the reduced density of postsynaptic endocytic zones and to impaired AMPAR internalization. These findings demonstrate a novel and essential role for Parkin in glutamatergic neurotransmission, as a stabilizer of postsynaptic Homer1 and the Homer1-linked endocytic machinery necessary for maintaining normal cell-surface AMPAR levels. Mutations in Parkin, a ubiquitinating enzyme, lead to the selective loss of midbrain dopaminergic neurons and juvenile-onset Parkinson's disease (PD). Parkin loss of function has also been shown to alter hippocampal glutamatergic neurotransmission, providing a potential explanation for PD-associated cognitive impairment. However, very little is known about Parkin's specific sites or mechanisms of action at glutamatergic synapses. Here, we show that Parkin deficiency leads to decreased AMPA receptor-mediated activity due to disruption of the postsynaptic endocytic zones required for maintaining proper cell-surface AMPA receptor levels. These findings demonstrate a novel role for Parkin in synaptic AMPA receptor internalization and suggest a Parkin-dependent mechanism for hippocampal dysfunction that may explain cognitive deficits associated with

Parkin-catalyzed Ubiquitin-Ester Transfer Is Triggered by PINK1-dependent Phosphorylation*

PubMed Central

Iguchi, Masahiro; Kujuro, Yuki; Okatsu, Kei; Koyano, Fumika; Kosako, Hidetaka; Kimura, Mayumi; Suzuki, Norihiro; Uchiyama, Shinichiro; Tanaka, Keiji; Matsuda, Noriyuki

2013-01-01

PINK1 and PARKIN are causal genes for autosomal recessive familial Parkinsonism. PINK1 is a mitochondrial Ser/Thr kinase, whereas Parkin functions as an E3 ubiquitin ligase. Under steady-state conditions, Parkin localizes to the cytoplasm where its E3 activity is repressed. A decrease in mitochondrial membrane potential triggers Parkin E3 activity and recruits it to depolarized mitochondria for ubiquitylation of mitochondrial substrates. The molecular basis for how the E3 activity of Parkin is re-established by mitochondrial damage has yet to be determined. Here we provide in vitro biochemical evidence for ubiquitin-thioester formation on Cys-431 of recombinant Parkin. We also report that Parkin forms a ubiquitin-ester following a decrease in mitochondrial membrane potential in cells, and that this event is essential for substrate ubiquitylation. Importantly, the Parkin RING2 domain acts as a transthiolation or acyl-transferring domain rather than an E2-recruiting domain. Furthermore, formation of the ubiquitin-ester depends on PINK1 phosphorylation of Parkin Ser-65. A phosphorylation-deficient mutation completely inhibited formation of the Parkin ubiquitin-ester intermediate, whereas phosphorylation mimics, such as Ser to Glu substitution, enabled partial formation of the intermediate irrespective of Ser-65 phosphorylation. We propose that PINK1-dependent phosphorylation of Parkin leads to the ubiquitin-ester transfer reaction of the RING2 domain, and that this is an essential step in Parkin activation. PMID:23754282

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. Copyright © 2016 Elsevier Inc. All rights reserved.

Parkin overexpression protects retinal ganglion cells against glutamate excitotoxicity.

PubMed

Hu, Xinxin; Dai, Yi; Sun, Xinghuai

2017-01-01

To investigate the role of parkin in regulating mitochondrial homeostasis of retinal ganglion cells (RGCs) under glutamate excitotoxicity. Rat RGCs were purified from dissociated retinal tissue with a modified two-step panning protocol. Cultured RGCs were transfected with parkin using an adenovirus system. The distribution and morphology of mitochondria in the RGCs were assessed with MitoTracker. The expression and distribution of parkin and optineurin proteins were measured with western blot analysis and immunofluorescence. Cytotoxicity of RGCs was evaluated by measuring lactate dehydrogenase (LDH) activity. Mitochondrial membrane potential was determined with the JC-1 assay. The expression of Bax and Bcl-2 were measured with western blot analysis. In the presence of glutamate-induced excitotoxicity, the number of mitochondria in the axons of the RGCs was predominantly increased, and the mitochondrial membrane potential in RGCs was depolarized. The expression of the parkin and optineurin proteins was upregulated and distributed mostly in the axons of the RGCs. Overexpression of parkin stabilized the mitochondrial membrane potential of RGCs, decreased cytotoxicity and apoptosis, attenuated the expression of Bax, and promoted the expression of optineurin under glutamate excitotoxicity. Overexpression of parkin exerted a significant protective effect on cultured RGCs against glutamate excitotoxicity. Interventions to alter the parkin-mediated mitochondria pathway may be useful in protecting RGCs against excitotoxic RGC damage.

Mechanisms of mitophagy: PINK1, Parkin, USP30 and beyond.

PubMed

Bingol, Baris; Sheng, Morgan

2016-11-01

Mitochondrial quality control is central for maintaining a healthy population of mitochondria. Two Parkinson's disease genes, mitochondrial kinase PINK1 and ubiquitin ligase Parkin, degrade damaged mitochondria though mitophagy. In this pathway, PINK1 senses mitochondrial damage and activates Parkin by phosphorylating Parkin and ubiquitin. Activated Parkin then builds ubiquitin chains on damaged mitochondria to tag them for degradation in lysosomes. USP30 deubiquitinase acts as a brake on mitophagy by opposing Parkin-mediated ubiquitination. Human genetic data point to a role for mitophagy defects in neurodegenerative diseases. This review highlights the molecular mechanisms of the mitophagy pathway and the recent advances in the understanding of mitophagy in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

Lipid profiling of parkin-mutant human skin fibroblasts.

PubMed

Lobasso, Simona; Tanzarella, Paola; Vergara, Daniele; Maffia, Michele; Cocco, Tiziana; Corcelli, Angela

2017-12-01

Parkin mutations are a major cause of early-onset Parkinson's disease (PD). The impairment of protein quality control system together with defects in mitochondria and autophagy process are consequences of the lack of parkin, which leads to neurodegeneration. Little is known about the role of lipids in these alterations of cell functions. In the present study, parkin-mutant human skin primary fibroblasts have been considered as cellular model of PD to investigate on possible lipid alterations associated with the lack of parkin protein. Dermal fibroblasts were obtained from two unrelated PD patients with different parkin mutations and their lipid compositions were compared with that of two control fibroblasts. The lipid extracts of fibroblasts have been analyzed by combined matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) and thin-layer chromatography (TLC). In parallel, we have performed direct MALDI-TOF/MS lipid analyses of intact fibroblasts by skipping lipid extraction steps. Results show that the proportions of some phospholipids and glycosphingolipids were altered in the lipid profiles of parkin-mutant fibroblasts. The detected higher level of gangliosides, phosphatidylinositol, and phosphatidylserine could be linked to dysfunction of autophagy and mitochondrial turnover; in addition, the lysophosphatidylcholine increase could represent the marker of neuroinflammatory state, a well-known component of PD. © 2017 Wiley Periodicals, Inc.

Parkin mediates the ubiquitination of VPS35 and modulates retromer-dependent endosomal sorting.

PubMed

Williams, Erin T; Glauser, Liliane; Tsika, Elpida; Jiang, Haisong; Islam, Shariful; Moore, Darren J

2018-06-11

Mutations in a number of genes cause familial forms of Parkinson's disease (PD), including mutations in the vacuolar protein sorting 35 ortholog (VPS35) and parkin genes. In this study, we identify a novel functional interaction between parkin and VPS35. We demonstrate that parkin interacts with and robustly ubiquitinates VPS35 in human neural cells. Familial parkin mutations are impaired in their ability to ubiquitinate VPS35. Parkin mediates the attachment of an atypical poly-ubiquitin chain to VPS35 with three lysine residues identified within the C-terminal region of VPS35 that are covalently modified by ubiquitin. Notably, parkin-mediated VPS35 ubiquitination does not promote the proteasomal degradation of VPS35. Furthermore, parkin does not influence the steady-state levels or turnover of VPS35 in neural cells and VPS35 levels are normal in the brains of parkin knockout mice. These data suggest that ubiquitination of VPS35 by parkin may instead serve a non-degradative cellular function potentially by regulating retromer-dependent sorting. Accordingly, we find that components of the retromer-associated WASH complex are markedly decreased in the brain of parkin knockout mice, suggesting that parkin may modulate WASH complex-dependent retromer sorting. Parkin gene silencing in primary cortical neurons selectively disrupts the vesicular sorting of the autophagy receptor ATG9A, a WASH-dependent retromer cargo. Parkin is not required for dopaminergic neurodegeneration induced by the expression of PD-linked D620N VPS35 in mice, consistent with VPS35 being located downstream of parkin function. Our data reveal a novel functional interaction of parkin with VPS35 that may be important for retromer-mediated endosomal sorting and PD.

Loss of Parkin Impairs Mitochondrial Function and Leads to Muscle Atrophy.

PubMed

Peker, Nesibe; Donipadi, Vinay; Sharma, Mridula; McFarlane, Craig; Kambadur, Ravi

2018-03-21

Parkinson's Disease is a neurodegenerative disease characterized by tremors, muscle stiffness and muscle weakness. Molecular genetic analysis confirmed that mutations in PARKIN and PINK1 genes, which play major roles in mitochondrial quality control and mitophagy, are frequently associated with Parkinson's Disease. PARKIN is an E3 ubiquitin ligase that translocates to mitochondria during loss of mitochondrial membrane potential to increase mitophagy. Although muscle dysfunction is noted in Parkinson's Disease, little is known about the involvement of PARKIN in the muscle phenotype of Parkinson's Disease. In this study, we report that the mitochondrial uncoupler CCCP promotes PINK1/PARKIN-mediated mitophagy in myogenic C2C12 cells. As a result of this excess mitophagy, we show that CCCP treatment of myotubes leads to the development of myotube atrophy in vitro. Surprisingly, we also found that siRNA-mediated knock down of Parkin results in accumulation of dysfunctional mitochondria, possibly due to impaired mitochondrial turnover. In addition, knock down of Parkin led to myotubular atrophy in vitro. Consistent with these in vitro results, Parkin knockout muscles showed impaired mitochondrial function and smaller myofiber area, suggesting that Parkin function is required for post-natal skeletal muscle growth and development.

Landscape of the PARKIN-dependent ubiquitylome in response to mitochondrial depolarization

PubMed Central

Sarraf, Shireen A.; Raman, Malavika; Guarani-Pereira, Virginia; Sowa, Mathew E.; Huttlin, Edward L.; Gygi, Steven P.; Harper, J. Wade

2013-01-01

The PARKIN (PARK2) ubiquitin ligase and its regulatory kinase PINK1 (PARK6), often mutated in familial early onset Parkinson’s Disease (PD), play central roles in mitochondrial homeostasis and mitophagy.1–3 While PARKIN is recruited to the mitochondrial outer membrane (MOM) upon depolarization via PINK1 action and can ubiquitylate Porin, Mitofusin, and Miro proteins on the MOM,1,4–11 the full repertoire of PARKIN substrates – the PARKIN-dependent ubiquitylome - remains poorly defined. Here we employ quantitative diGLY capture proteomics12,13 to elucidate the ubiquitylation site-specificity and topology of PARKIN-dependent target modification in response to mitochondrial depolarization. Hundreds of dynamically regulated ubiquitylation sites in dozens of proteins were identified, with strong enrichment for MOM proteins, indicating that PARKIN dramatically alters the ubiquitylation status of the mitochondrial proteome. Using complementary interaction proteomics, we found depolarization-dependent PARKIN association with numerous MOM targets, autophagy receptors, and the proteasome. Mutation of PARKIN’s active site residue C431, which has been found mutated in PD patients, largely disrupts these associations. Structural and topological analysis revealed extensive conservation of PARKIN-dependent ubiquitylation sites on cytoplasmic domains in vertebrate and D. melanogaster MOM proteins. These studies provide a resource for understanding how the PINK1-PARKIN pathway re-sculpts the proteome to support mitochondrial homeostasis. PMID:23503661

Overexpression of parkin in the rat nigrostriatal dopamine system protects against methamphetamine neurotoxicity.

PubMed

Liu, Bin; Traini, Roberta; Killinger, Bryan; Schneider, Bernard; Moszczynska, Anna

2013-09-01

Methamphetamine (METH) is a central nervous system psychostimulant with a high potential for abuse. At high doses, METH causes a selective degeneration of dopaminergic terminals in the striatum, sparing other striatal terminals and cell bodies. We previously detected a deficit in parkin after binge METH in rat striatal synaptosomes. Parkin is an ubiquitin-protein E3 ligase capable of protecting dopamine neurons from diverse cellular insults. Whether the deficit in parkin mediates the toxicity of METH and whether parkin can protect from toxicity of the drug is unknown. The present study investigated whether overexpression of parkin attenuates degeneration of striatal dopaminergic terminals exposed to binge METH. Parkin overexpression in rat nigrostriatal dopamine system was achieved by microinjection of adeno-associated viral transfer vector 2/6 encoding rat parkin (AAV2/6-parkin) into the substantia nigra pars compacta. The microinjections of AAV2/6-parkin dose-dependently increased parkin levels in both the substantia nigra pars compacta and striatum. The levels of dopamine synthesizing enzyme, tyrosine hydroxylase, remained at the control levels; therefore, tyrosine hydroxylase immunoreactivity was used as an index of dopaminergic terminal integrity. In METH-exposed rats, the increase in parkin levels attenuated METH-induced decreases in striatal tyrosine hydroxylase immunoreactivity in a dose-dependent manner, indicating that parkin can protect striatal dopaminergic terminals against METH neurotoxicity. Copyright © 2013 Elsevier Inc. All rights reserved.

Site-specific Interaction Mapping of Phosphorylated Ubiquitin to Uncover Parkin Activation*♦

PubMed Central

Yamano, Koji; Queliconi, Bruno B.; Koyano, Fumika; Saeki, Yasushi; Hirokawa, Takatsugu; Tanaka, Keiji; Matsuda, Noriyuki

2015-01-01

Damaged mitochondria are eliminated through autophagy machinery. A cytosolic E3 ubiquitin ligase Parkin, a gene product mutated in familial Parkinsonism, is essential for this pathway. Recent progress has revealed that phosphorylation of both Parkin and ubiquitin at Ser65 by PINK1 are crucial for activation and recruitment of Parkin to the damaged mitochondria. However, the mechanism by which phosphorylated ubiquitin associates with and activates phosphorylated Parkin E3 ligase activity remains largely unknown. Here, we analyze interactions between phosphorylated forms of both Parkin and ubiquitin at a spatial resolution of the amino acid residue by site-specific photo-crosslinking. We reveal that the in-between-RING (IBR) domain along with RING1 domain of Parkin preferentially binds to ubiquitin in a phosphorylation-dependent manner. Furthermore, another approach, the Fluoppi (fluorescent-based technology detecting protein-protein interaction) assay, also showed that pathogenic mutations in these domains blocked interactions with phosphomimetic ubiquitin in mammalian cells. Molecular modeling based on the site-specific photo-crosslinking interaction map combined with mass spectrometry strongly suggests that a novel binding mechanism between Parkin and ubiquitin leads to a Parkin conformational change with subsequent activation of Parkin E3 ligase activity. PMID:26260794

Proteomic Analysis of Parkin Isoforms Expression in Different Rat Brain Areas.

PubMed

D'Amico, Agata Grazia; Maugeri, Grazia; Reitano, Rita; Cavallaro, Sebastiano; D'Agata, Velia

2016-10-01

PARK2 gene's mutations are related to the familial form of juvenile Parkinsonism, also known as the autosomic recessive juvenile Parkinsonism. This gene encodes for parkin, a 465-amino acid protein. To date, a large number of parkin isoforms, generated by an alternative splicing mechanism, have been described. Currently, Gene Bank lists 27 rat PARK2 transcripts, which matches to 20 exclusive parkin alternative splice variants. Despite the existence of these isoforms, most of the studies carried out so far, have been focused only on the originally cloned parkin. In this work we have analyzed the expression profile of parkin isoforms in some rat brain areas including prefrontal cortex, hippocampus, substantia nigra and cerebellum. To discriminate among these isoforms, we detected their localization through the use of two antibodies that are able to identify different domains of the parkin canonical sequence. Our analysis has revealed that at least fourteen parkin isoforms are expressed in rat brain with a various distribution in the regions analyzed. Our study might help to elucidate the pathophysiological role of these proteins in the central nervous system.

Parkin and PINK1 functions in oxidative stress and neurodegeneration.

PubMed

Barodia, Sandeep K; Creed, Rose B; Goldberg, Matthew S

2017-07-01

Loss-of-function mutations in the genes encoding Parkin and PINK1 are causally linked to autosomal recessive Parkinson's disease (PD). Parkin, an E3 ubiquitin ligase, and PINK1, a mitochondrial-targeted kinase, function together in a common pathway to remove dysfunctional mitochondria by autophagy. Presumably, deficiency for Parkin or PINK1 impairs mitochondrial autophagy and thereby increases oxidative stress due to the accumulation of dysfunctional mitochondria that release reactive oxygen species. Parkin and PINK1 likely have additional functions that may be relevant to the mechanisms by which mutations in these genes cause neurodegeneration, such as regulating inflammation, apoptosis, or dendritic morphogenesis. Here we briefly review what is known about functions of Parkin and PINK1 related to oxidative stress and neurodegeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

Parkin Regulates Mitosis and Genomic Stability through Cdc20/Cdh1.

PubMed

Lee, Seung Baek; Kim, Jung Jin; Nam, Hyun-Ja; Gao, Bowen; Yin, Ping; Qin, Bo; Yi, Sang-Yeop; Ham, Hyoungjun; Evans, Debra; Kim, Sun-Hyun; Zhang, Jun; Deng, Min; Liu, Tongzheng; Zhang, Haoxing; Billadeau, Daniel D; Wang, Liewei; Giaime, Emilie; Shen, Jie; Pang, Yuan-Ping; Jen, Jin; van Deursen, Jan M; Lou, Zhenkun

2015-10-01

Mutations in the E3 ubiquitin ligase Parkin have been linked to familial Parkinson's disease. Parkin has also been implicated in mitosis through mechanisms that are unclear. Here we show that Parkin interacts with anaphase promoting complex/cyclosome (APC/C) coactivators Cdc20 and Cdh1 to mediate the degradation of several key mitotic regulators independent of APC/C. We demonstrate that ordered progression through mitosis is orchestrated by two distinct E3 ligases through the shared use of Cdc20 and Cdh1. Furthermore, Parkin is phosphorylated and activated by polo-like kinase 1 (Plk1) during mitosis. Parkin deficiency results in overexpression of its substrates, mitotic defects, genomic instability, and tumorigenesis. These results suggest that the Parkin-Cdc20/Cdh1 complex is an important regulator of mitosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Hydrocortisone-induced parkin prevents dopaminergic cell death via CREB pathway in Parkinson's disease model.

PubMed

Ham, Sangwoo; Lee, Yun-Il; Jo, Minkyung; Kim, Hyojung; Kang, Hojin; Jo, Areum; Lee, Gum Hwa; Mo, Yun Jeong; Park, Sang Chul; Lee, Yun Song; Shin, Joo-Ho; Lee, Yunjong

2017-04-03

Dysfunctional parkin due to mutations or post-translational modifications contributes to dopaminergic neurodegeneration in Parkinson's disease (PD). Overexpression of parkin provides protection against cellular stresses and prevents dopamine cell loss in several PD animal models. Here we performed an unbiased high-throughput luciferase screening to identify chemicals that can increase parkin expression. Among promising parkin inducers, hydrocortisone possessed the most favorable profiles including parkin induction ability, cell protection ability, and physicochemical property of absorption, distribution, metabolism, and excretion (ADME) without inducing endoplasmic reticulum stress. We found that hydrocortisone-induced parkin expression was accountable for cell protection against oxidative stress. Hydrocortisone-activated parkin expression was mediated by CREB pathway since gRNA to CREB abolished hydrocortisone's ability to induce parkin. Finally, hydrocortisone treatment in mice increased brain parkin levels and prevented 6-hydroxy dopamine induced dopamine cell loss when assessed at 4 days after the toxin's injection. Our results showed that hydrocortisone could stimulate parkin expression via CREB pathway and the induced parkin expression was accountable for its neuroprotective effect. Since glucocorticoid is a physiological hormone, maintaining optimal levels of glucocorticoid might be a potential therapeutic or preventive strategy for Parkinson's disease.

Parkin targets HIF-1α for ubiquitination and degradation to inhibit breast tumor progression.

PubMed

Liu, Juan; Zhang, Cen; Zhao, Yuhan; Yue, Xuetian; Wu, Hao; Huang, Shan; Chen, James; Tomsky, Kyle; Xie, Haiyang; Khella, Christen A; Gatza, Michael L; Xia, Dajing; Gao, Jimin; White, Eileen; Haffty, Bruce G; Hu, Wenwei; Feng, Zhaohui

2017-11-28

Mutations in E3 ubiquitin ligase Parkin have been linked to familial Parkinson's disease. Accumulating evidence suggests that Parkin is a tumor suppressor, but the underlying mechanism is poorly understood. Here we show that Parkin is an E3 ubiquitin ligase for hypoxia-inducible factor 1α (HIF-1α). Parkin interacts with HIF-1α and promotes HIF-1α degradation through ubiquitination, which in turn inhibits metastasis of breast cancer cells. Parkin downregulation in breast cancer cells promotes metastasis, which can be inhibited by targeting HIF-1α with RNA interference or the small-molecule inhibitor YC-1. We further identify lysine 477 (K477) of HIF-1α as a major ubiquitination site for Parkin. K477R HIF-1α mutation and specific cancer-associated Parkin mutations largely abolish the functions of Parkin to ubiquitinate HIF-1α and inhibit cancer metastasis. Importantly, Parkin expression is inversely correlated with HIF-1α expression and metastasis in breast cancer. Our results reveal an important mechanism for Parkin in tumor suppression and HIF-1α regulation.

Parkin is activated by PINK1-dependent phosphorylation of ubiquitin at Ser65

PubMed Central

Kazlauskaite, Agne; Kondapalli, Chandana; Gourlay, Robert; Campbell, David G.; Ritorto, Maria Stella; Hofmann, Kay; Alessi, Dario R.; Knebel, Axel; Trost, Matthias; Muqit, Miratul M. K.

2014-01-01

We have previously reported that the Parkinson's disease-associated kinase PINK1 (PTEN-induced putative kinase 1) is activated by mitochondrial depolarization and stimulates the Parkin E3 ligase by phosphorylating Ser65 within its Ubl (ubiquitin-like) domain. Using phosphoproteomic analysis, we identified a novel ubiquitin phosphopeptide phosphorylated at Ser65 that was enriched 14-fold in HEK (human embryonic kidney)-293 cells overexpressing wild-type PINK1 stimulated with the mitochondrial uncoupling agent CCCP (carbonyl cyanide m-chlorophenylhydrazone), to activate PINK1, compared with cells expressing kinase-inactive PINK1. Ser65 in ubiquitin lies in a similar motif to Ser65 in the Ubl domain of Parkin. Remarkably, PINK1 directly phosphorylates Ser65 of ubiquitin in vitro. We undertook a series of experiments that provide striking evidence that Ser65-phosphorylated ubiquitin (ubiquitinPhospho−Ser65) functions as a critical activator of Parkin. First, we demonstrate that a fragment of Parkin lacking the Ubl domain encompassing Ser65 (ΔUbl-Parkin) is robustly activated by ubiquitinPhospho−Ser65, but not by non-phosphorylated ubiquitin. Secondly, we find that the isolated Parkin Ubl domain phosphorylated at Ser65 (UblPhospho−Ser65) can also activate ΔUbl-Parkin similarly to ubiquitinPhospho−Ser65. Thirdly, we establish that ubiquitinPhospho−Ser65, but not non-phosphorylated ubiquitin or UblPhospho−Ser65, activates full-length wild-type Parkin as well as the non-phosphorylatable S65A Parkin mutant. Fourthly, we provide evidence that optimal activation of full-length Parkin E3 ligase is dependent on PINK1-mediated phosphorylation of both Parkin at Ser65 and ubiquitin at Ser65, since only mutation of both proteins at Ser65 completely abolishes Parkin activation. In conclusion, the findings of the present study reveal that PINK1 controls Parkin E3 ligase activity not only by phosphorylating Parkin at Ser65, but also by phosphorylating ubiquitin at Ser65

Olfaction in Parkin carriers in Chinese patients with Parkinson disease.

PubMed

Wang, Ying; Wu, Jian-Jun; Liu, Feng-Tao; Chen, Kui; Chen, Chen; Luo, Su-Shan; Wang, Yi-Xuan; Li, Da-Ke; Guan, Rong-Yuan; Yang, Yu-Jie; An, Yu; Wang, Jian; Sun, Yi-Min

2017-05-01

Olfactory identification was reported to be better among PD (Parkinson disease) patients with Parkin mutations, but previous studies didn't eliminate the interference of other PD related genes on olfaction, and whether olfaction of Parkin mutations patients was better in Chinese population was still unknown. To assess olfaction function among PD patients with Parkin mutations in Chinese population. A total of 226 PD patients with a positive family history or an early-onset age (<50 years) were enrolled for genetic testing of PD related genes by target sequencing and multiple ligation-dependent probe amplification. The clinical data including olfactory function test were investigated. Linear regression was performed to adjust for the covariates between all groups. There were 68 patients found having a negative result in PD genetic testing and 43 patients carrying homozygous or compound heterozygous Parkin mutations. Among them, 49 PD panel negative patients and 33 PD- Parkin patients had results of olfactory assessment. PD -Parkin patients performed significantly better on the Sniffin' Sticks tests than panel negative patients (8.0 ± 1.7 vs. 5.7 ± 1.9, p  <   .001), but still worse compared to healthy controls (9.4 ± 1.5, p  =   .003). These differences persisted after adjusting for confounders. Among Chinese population, PD -Parkin patients had relatively preserved olfaction compared to PD panel negative patients after eliminating the interference of other PD related genes, but were still worse than healthy controls.

Extracellular Alpha-Synuclein Oligomers Induce Parkin S-Nitrosylation: Relevance to Sporadic Parkinson's Disease Etiopathology.

PubMed

Wilkaniec, Anna; Lenkiewicz, Anna M; Czapski, Grzegorz A; Jęśko, Henryk M; Hilgier, Wojciech; Brodzik, Robert; Gąssowska-Dobrowolska, Magdalena; Culmsee, Carsten; Adamczyk, Agata

2018-04-21

α-Synuclein (ASN) and parkin, a multifunctional E3 ubiquitin ligase, are two proteins that are associated with the pathophysiology of Parkinson's disease (PD). Excessive release of ASN, its oligomerization, aggregation, and deposition in the cytoplasm contribute to neuronal injury and cell death through oxidative-nitrosative stress induction, mitochondrial impairment, and synaptic dysfunction. In contrast, overexpression of parkin provides protection against cellular stresses and prevents dopaminergic neural cell loss in several animal models of PD. However, the influence of ASN on the function of parkin is largely unknown. Therefore, the aim of this study was to investigate the effect of extracellular ASN oligomers on parkin expression, S-nitrosylation, as well as its activity. For these investigations, we used rat pheochromocytoma (PC12) cell line treated with exogenous oligomeric ASN as well as PC12 cells with parkin overexpression and parkin knock-down. The experiments were performed using spectrophotometric, spectrofluorometric, and immunochemical methods. We found that exogenous ASN oligomers induce oxidative/nitrosative stress leading to parkin S-nitrosylation. Moreover, this posttranslational modification induced the elevation of parkin autoubiquitination and degradation of the protein. The decreased parkin levels resulted in significant cell death, whereas parkin overexpression protected against toxicity induced by extracellular ASN oligomers. We conclude that lowering parkin levels by extracellular ASN may significantly contribute to the propagation of neurodegeneration in PD pathology through accumulation of defective proteins as a consequence of parkin degradation.

Structure of phosphorylated UBL domain and insights into PINK1-orchestrated parkin activation.

PubMed

Aguirre, Jacob D; Dunkerley, Karen M; Mercier, Pascal; Shaw, Gary S

2017-01-10

Mutations in PARK2 and PARK6 genes are responsible for the majority of hereditary Parkinson's disease cases. These genes encode the E3 ubiquitin ligase parkin and the protein kinase PTEN-induced kinase 1 (PINK1), respectively. Together, parkin and PINK1 regulate the mitophagy pathway, which recycles damaged mitochondria following oxidative stress. Native parkin is inactive and exists in an autoinhibited state mediated by its ubiquitin-like (UBL) domain. PINK1 phosphorylation of serine 65 in parkin's UBL and serine 65 of ubiquitin fully activate ubiquitin ligase activity; however, a structural rationale for these observations is not clear. Here, we report the structure of the phosphorylated UBL domain from parkin. We find that destabilization of the UBL results from rearrangements to hydrophobic core packing that modify its structure. Altered surface electrostatics from the phosphoserine group disrupt its intramolecular association, resulting in poorer autoinhibition in phosphorylated parkin. Further, we show that phosphorylation of both the UBL domain and ubiquitin are required to activate parkin by releasing the UBL domain, forming an extended structure needed to facilitate E2-ubiquitin binding. Together, the results underscore the importance of parkin activation by the PINK1 phosphorylation signal and provide a structural picture of the unraveling of parkin's ubiquitin ligase potential.

Parkin induces G2/M cell cycle arrest in TNF-α-treated HeLa cells.

PubMed

Lee, Min Ho; Cho, Yoonjung; Jung, Byung Chul; Kim, Sung Hoon; Kang, Yeo Wool; Pan, Cheol-Ho; Rhee, Ki-Jong; Kim, Yoon Suk

2015-08-14

Parkin is a known tumor suppressor. However, the mechanism by which parkin acts as a tumor suppressor remains to be fully elucidated. Previously, we reported that parkin expression induces caspase-dependent apoptotic cell death in TNF-α-treated HeLa cells. However, at that time, we did not consider the involvement of parkin in cell cycle control. In the current study, we investigated whether parkin is involved in cell cycle regulation and suppression of cancer cell growth. In our cell cycle analyses, parkin expression induced G2/M cell cycle arrest in TNF-α-treated HeLa cells. To elucidate the mechanism(s) by which parkin induces this G2/M arrest, we analyzed cell cycle regulatory molecules involved in the G2/M transition. Parkin expression induced CDC2 phosphorylation which is known to inhibit CDC2 activity and cause G2/M arrest. Cyclin B1, which is degraded during the mitotic transition, accumulated in response to parkin expression, thereby indicating parkin-induced G2/M arrest. Next, we established that Myt1, which is known to phosphorylate and inhibit CDC2, increased following parkin expression. In addition, we found that parkin also induces increased Myt1 expression, G2/M arrest, and reduced cell viability in TNF-α-treated HCT15 cells. Furthermore, knockdown of parkin expression by parkin-specific siRNA decreased Myt1 expression and phosphorylation of CDC2 and resulted in recovered cell viability. These results suggest that parkin acts as a crucial molecule causing cell cycle arrest in G2/M, thereby suppressing tumor cell growth. Copyright © 2015 Elsevier Inc. All rights reserved.

Quantitative proteomics reveal a feedforward mechanism for mitochondrial PARKIN translocation and ubiquitin chain synthesis.

PubMed

Ordureau, Alban; Sarraf, Shireen A; Duda, David M; Heo, Jin-Mi; Jedrychowski, Mark P; Sviderskiy, Vladislav O; Olszewski, Jennifer L; Koerber, James T; Xie, Tiao; Beausoleil, Sean A; Wells, James A; Gygi, Steven P; Schulman, Brenda A; Harper, J Wade

2014-11-06

Phosphorylation is often used to promote protein ubiquitylation, yet we rarely understand quantitatively how ligase activation and ubiquitin (UB) chain assembly are integrated with phosphoregulation. Here we employ quantitative proteomics and live-cell imaging to dissect individual steps in the PINK1 kinase-PARKIN UB ligase mitochondrial control pathway disrupted in Parkinson's disease. PINK1 plays a dual role by phosphorylating PARKIN on its UB-like domain and poly-UB chains on mitochondria. PARKIN activation by PINK1 produces canonical and noncanonical UB chains on mitochondria, and PARKIN-dependent chain assembly is required for accumulation of poly-phospho-UB (poly-p-UB) on mitochondria. In vitro, PINK1 directly activates PARKIN's ability to assemble canonical and noncanonical UB chains and promotes association of PARKIN with both p-UB and poly-p-UB. Our data reveal a feedforward mechanism that explains how PINK1 phosphorylation of both PARKIN and poly-UB chains synthesized by PARKIN drives a program of PARKIN recruitment and mitochondrial ubiquitylation in response to mitochondrial damage. Copyright © 2014 Elsevier Inc. All rights reserved.

Parkin in Parkinson's Disease and Cancer: a Double-Edged Sword.

PubMed

Wahabi, Khushnuma; Perwez, Ahmad; Rizvi, Moshahid A

2018-01-18

Parkin for more than a decade has been portrayed as a neuroprotector gene is now increasingly emerging as a multifaceted gene that can exert entirely opposite effects i.e., both cell proliferation and apoptosis. Parkinson's disease, a neurological disease, progresses due to excess in cell death, while, in case of cancer, cell death normally fails to occur. Parkin, an E3 ubiquitin ligase, was first identified as a gene implicated in autosomal recessive juvenile Parkinsonism, but several evidences indicate that Parkin is a tumor suppressor gene, involved in a variety of cancers. It is hard to imagine that two entirely different classes of disease, like cancer and Parkinson's disease, can converge at a critical point attributable to a single gene, Parkin. This mysterious and hidden connection may prove a boon in disguise and has raised hopes that studying the biology of one disease may help to identify novel targets of therapy for the other. In this Parkinson's disease-cancer story, if the detail of Parkin pathway is unraveled and gaps in the storyline are properly filled up, we may end getting an entirely new therapeutic option. This review mainly highlights the recent literature which suggests how Parkin gene regulates the various hallmarks of both the Parkinson's disease and cancer.

Role of Parkin and endurance training on mitochondrial turnover in skeletal muscle.

PubMed

Chen, Chris Chin Wah; Erlich, Avigail T; Hood, David A

2018-03-17

Parkin is a ubiquitin ligase that is involved in the selective removal of dysfunctional mitochondria. This process is termed mitophagy and can assist in mitochondrial quality control. Endurance training can produce adaptations in skeletal muscle toward a more oxidative phenotype, an outcome of enhanced mitochondrial biogenesis. It remains unknown whether Parkin-mediated mitophagy is involved in training-induced increases in mitochondrial content and function. Our purpose was to determine a role for Parkin in maintaining mitochondrial turnover in muscle, and its requirement in mediating mitochondrial biogenesis following endurance exercise training. Wild-type and Parkin knockout (KO) mice were trained for 6 weeks and then treated with colchicine or vehicle to evaluate the role of Parkin in mediating changes in mitochondrial content, function and acute exercise-induced mitophagy flux. Our results indicate that Parkin is required for the basal maintenance of mitochondrial function. The absence of Parkin did not significantly alter mitophagy basally; however, acute exercise produced an elevation in mitophagy flux, a response that was Parkin-dependent. Mitochondrial content was increased following training in both genotypes, but this occurred without an induction of PGC-1α signaling in KO animals. Interestingly, the increased muscle mitochondrial content in response to training did not influence basal mitophagy flux, despite an enhanced expression and localization of Parkin to mitochondria in WT animals. Furthermore, exercise-induced mitophagy flux was attenuated with training in WT animals, suggesting a lower rate of mitochondrial degradation resulting from improved organelle quality with training. In contrast, training led to a higher mitochondrial content, but with persistent dysfunction, in KO animals. Thus, the lack of a rescue of mitochondrial dysfunction with training in the absence of Parkin is the likely reason for the impaired training-induced attenuation of

Parkin Mutations Reduce the Complexity of Neuronal Processes in iPSC-derived Human Neurons

PubMed Central

Ren, Yong; Jiang, Houbo; Hu, Zhixing; Fan, Kevin; Wang, Jun; Janoschka, Stephen; Wang, Xiaomin; Ge, Shaoyu; Feng, Jian

2015-01-01

Parkinson’s disease (PD) is characterized by the degeneration of nigral dopaminergic (DA) neurons and non-DA neurons in many parts of the brain. Mutations of parkin, an E3 ubiquitin ligase that strongly binds to microtubules, are the most frequent cause of recessively inherited Parkinson’s disease. The lack of robust PD phenotype in parkin knockout mice suggests a unique vulnerability of human neurons to parkin mutations. Here, we show that the complexity of neuronal processes as measured by total neurite length, number of terminals, number of branch points and Sholl analysis, was greatly reduced in induced pluripotent stem cell (iPSC)-derived TH+ or TH− neurons from PD patients with parkin mutations. Consistent with these, microtubule stability was significantly decreased by parkin mutations in iPSC-derived neurons. Overexpression of parkin, but not its PD-linked mutant nor GFP, restored the complexity of neuronal processes and the stability of microtubules. Consistent with these, the microtubule-depolymerizing agent colchicine mimicked the effect of parkin mutations by decreasing neurite length and complexity in control neurons while the microtubule-stabilizing drug taxol mimicked the effect of parkin overexpression by enhancing the morphology of parkin-deficient neurons. The results suggest that parkin maintains the morphological complexity of human neurons by stabilizing microtubules. PMID:25332110

Parkin-phosphoubiquitin complex reveals cryptic ubiquitin-binding site required for RBR ligase activity.

PubMed

Kumar, Atul; Chaugule, Viduth K; Condos, Tara E C; Barber, Kathryn R; Johnson, Clare; Toth, Rachel; Sundaramoorthy, Ramasubramanian; Knebel, Axel; Shaw, Gary S; Walden, Helen

2017-05-01

RING-between-RING (RBR) E3 ligases are a class of ubiquitin ligases distinct from RING or HECT E3 ligases. An important RBR ligase is Parkin, mutations in which lead to early-onset hereditary Parkinsonism. Parkin and other RBR ligases share a catalytic RBR module but are usually autoinhibited and activated via distinct mechanisms. Recent insights into Parkin regulation predict large, unknown conformational changes during Parkin activation. However, current data on active RBR ligases reflect the absence of regulatory domains. Therefore, it remains unclear how individual RBR ligases are activated, and whether they share a common mechanism. We now report the crystal structure of a human Parkin-phosphoubiquitin complex, which shows that phosphoubiquitin binding induces movement in the 'in-between RING' (IBR) domain to reveal a cryptic ubiquitin-binding site. Mutation of this site negatively affects Parkin's activity. Furthermore, ubiquitin binding promotes cooperation between Parkin molecules, which suggests a role for interdomain association in the RBR ligase mechanism.

Parkin loss leads to PARIS-dependent declines in mitochondrial mass and respiration

PubMed Central

Stevens, Daniel A.; Lee, Yunjong; Kang, Ho Chul; Lee, Byoung Dae; Lee, Yun-Il; Bower, Aaron; Jiang, Haisong; Kang, Sung-Ung; Andrabi, Shaida A.; Dawson, Valina L.; Shin, Joo-Ho; Dawson, Ted M.

2015-01-01

Mutations in parkin lead to early-onset autosomal recessive Parkinson’s disease (PD) and inactivation of parkin is thought to contribute to sporadic PD. Adult knockout of parkin in the ventral midbrain of mice leads to an age-dependent loss of dopamine neurons that is dependent on the accumulation of parkin interacting substrate (PARIS), zinc finger protein 746 (ZNF746), and its transcriptional repression of PGC-1α. Here we show that adult knockout of parkin in mouse ventral midbrain leads to decreases in mitochondrial size, number, and protein markers consistent with a defect in mitochondrial biogenesis. This decrease in mitochondrial mass is prevented by short hairpin RNA knockdown of PARIS. PARIS overexpression in mouse ventral midbrain leads to decreases in mitochondrial number and protein markers and PGC-1α–dependent deficits in mitochondrial respiration. Taken together, these results suggest that parkin loss impairs mitochondrial biogenesis, leading to declining function of the mitochondrial pool and cell death. PMID:26324925

Exon dosage analysis of parkin gene in Chinese sporadic Parkinson's disease.

PubMed

Guo, Ji-Feng; Dong, Xiao-Li; Xu, Qian; Li, Nan; Yan, Xin-Xiang; Xia, Kun; Tang, Bei-Sha

2015-09-14

Parkin gene mutations are by far the most common mutations in both familial Parkinson's disease (PD) and sporadic PD. Approximately, 50% of parkin mutations is exon dosage mutations (i.e., deletions and duplications of entire exons). Here, we first established a MLPA assay for quick detection of parkin exon rearrangements. Then, we studied parkin exon dosage mutations in 755 Chinese sporadic PDdisease patients using the established MLPA assay. We found that there were 25 (3.3%) patients with exon dosage alterations including deletions and duplications, 20 (11.4%) patients with exon rearrangements in 178 early-onset patients, and 5 (0.86%) patients with exon rearrangement mutations in 579 later-onset patients. The percentage of individuals with parkin dosage mutations is more than 33% when the age at onset is less than 30 years old, but less than 7% when the age at onset is more than 30. In these mutations, deletion is the main mutational style, especially in exon 2-5. Our results indicated that exon dosage mutations in parkin gene might be the main cause for sporadic PD, especially in EOP. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

SESN2 facilitates mitophagy by helping Parkin translocation through ULK1 mediated Beclin1 phosphorylation.

PubMed

Kumar, Ashish; Shaha, Chandrima

2018-01-12

Mitophagy, the selective degradation of mitochondria by autophagy, is crucial for the maintenance of healthy mitochondrial pool in cells. The critical event in mitophagy is the translocation of cytosolic Parkin, a ubiquitin ligase, to the surface of defective mitochondria. This study elucidates a novel role of SESN2/Sestrin2, a stress inducible protein, in mitochondrial translocation of PARK2/Parkin during mitophagy. The data demonstrates that SESN2 downregulation inhibits BECN1/Beclin1 and Parkin interaction, thereby preventing optimum mitochondrial accumulation of Parkin. SESN2 interacts with ULK1 (unc-51 like kinase 1) and assists ULK1 mediated phosphorylation of Beclin1 at serine-14 position required for binding with Parkin prior to mitochondrial translocation. The trigger for SESN2 activation and regulation of Parkin translocation is the generation of mitochondrial superoxide. Scavenging of mitochondrial superoxide lower the levels of SESN2, resulting in retardation of Parkin translocation. Importantly, we observe that SESN2 mediated cytosolic interaction of Parkin and Beclin1 is PINK1 independent but mitochondrial translocation of Parkin is PINK1 dependent. Together, these findings suggest the role of SESN2 as a positive regulator of Parkin mediated mitophagy.

Molecular mechanisms underlying PINK1 and Parkin catalyzed ubiquitylation of substrates on damaged mitochondria.

PubMed

Koyano, Fumika; Matsuda, Noriyuki

2015-10-01

PINK1 and Parkin are gene products that cause genetic recessive Parkinsonism. PINK1 is a protein kinase and Parkin is a ubiquitin ligase (E3) that links ubiquitin to a substrate. Importantly, under steady state conditions, the enzymatic activity of Parkin is completely suppressed, but is activated when mitochondria become abnormal. In 2013 and 2014, biochemical and structure-function analyses revealed a number of critical mechanistic insights. First, Parkin is a self-inhibitory E3 that suppresses its E3 activity via intramolecular interactions. Second, in response to a decrease in mitochondrial membrane potential, PINK1 phosphorylates Ser65 in both the Parkin ubiquitin-like domain and ubiquitin itself. These phosphorylation events cooperate to relieve the Parkin autoinhibition. Third, activated Parkin forms a ubiquitin-thioester bond at Cys431 to produce a reaction intermediate that catalyzes ubiquitylation of substrates on damaged mitochondria. While the molecular mechanism regulating Parkin enzymatic activity has largely eluded clarification, a complete picture is now emerging. Copyright © 2015 Elsevier B.V. All rights reserved.

USP8 regulates mitophagy by removing K6-linked ubiquitin conjugates from parkin

PubMed Central

Durcan, Thomas M; Tang, Matthew Y; Pérusse, Joëlle R; Dashti, Eman A; Aguileta, Miguel A; McLelland, Gian-Luca; Gros, Priti; Shaler, Thomas A; Faubert, Denis; Coulombe, Benoit; Fon, Edward A

2014-01-01

Mutations in the Park2 gene, encoding the E3 ubiquitin-ligase parkin, are responsible for a familial form of Parkinson's disease (PD). Parkin-mediated ubiquitination is critical for the efficient elimination of depolarized dysfunctional mitochondria by autophagy (mitophagy). As damaged mitochondria are a major source of toxic reactive oxygen species within the cell, this pathway is believed to be highly relevant to the pathogenesis of PD. Little is known about how parkin-mediated ubiquitination is regulated during mitophagy or about the nature of the ubiquitin conjugates involved. We report here that USP8/UBPY, a deubiquitinating enzyme not previously implicated in mitochondrial quality control, is critical for parkin-mediated mitophagy. USP8 preferentially removes non-canonical K6-linked ubiquitin chains from parkin, a process required for the efficient recruitment of parkin to depolarized mitochondria and for their subsequent elimination by mitophagy. This work uncovers a novel role for USP8-mediated deubiquitination of K6-linked ubiquitin conjugates from parkin in mitochondrial quality control. PMID:25216678

Hepatitis C Virus Induces the Mitochondrial Translocation of Parkin and Subsequent Mitophagy

PubMed Central

Kim, Seong-Jun; Syed, Gulam H.; Siddiqui, Aleem

2013-01-01

Hepatitis C Virus (HCV) induces intracellular events that trigger mitochondrial dysfunction and promote host metabolic alterations. Here, we investigated selective autophagic degradation of mitochondria (mitophagy) in HCV-infected cells. HCV infection stimulated Parkin and PINK1 gene expression, induced perinuclear clustering of mitochondria, and promoted mitochondrial translocation of Parkin, an initial event in mitophagy. Liver tissues from chronic HCV patients also exhibited notable levels of Parkin induction. Using multiple strategies involving confocal and electron microscopy, we demonstrated that HCV-infected cells display greater number of mitophagosomes and mitophagolysosomes compared to uninfected cells. HCV-induced mitophagy was evidenced by the colocalization of LC3 puncta with Parkin-associated mitochondria and lysosomes. Ultrastructural analysis by electron microscopy and immunoelectron microscopy also displayed engulfment of damaged mitochondria in double membrane vesicles in HCV-infected cells. The HCV-induced mitophagy occurred irrespective of genotypic differences. Silencing Parkin and PINK1 hindered HCV replication suggesting the functional relevance of mitophagy in HCV propagation. HCV-mediated decline of mitochondrial complex I enzyme activity was rescued by chemical inhibition of mitophagy or by Parkin silencing. Overall our results suggest that HCV induces Parkin-dependent mitophagy, which may have significant contribution in mitochondrial liver injury associated with chronic hepatitis C. PMID:23555273

PINK1 Primes Parkin-Mediated Ubiquitination of PARIS in Dopaminergic Neuronal Survival.

PubMed

Lee, Yunjong; Stevens, Daniel A; Kang, Sung-Ung; Jiang, Haisong; Lee, Yun-Il; Ko, Han Seok; Scarffe, Leslie A; Umanah, George E; Kang, Hojin; Ham, Sangwoo; Kam, Tae-In; Allen, Kathleen; Brahmachari, Saurav; Kim, Jungwoo Wren; Neifert, Stewart; Yun, Seung Pil; Fiesel, Fabienne C; Springer, Wolfdieter; Dawson, Valina L; Shin, Joo-Ho; Dawson, Ted M

2017-01-24

Mutations in PTEN-induced putative kinase 1 (PINK1) and parkin cause autosomal-recessive Parkinson's disease through a common pathway involving mitochondrial quality control. Parkin inactivation leads to accumulation of the parkin interacting substrate (PARIS, ZNF746) that plays an important role in dopamine cell loss through repression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α) promoter activity. Here, we show that PARIS links PINK1 and parkin in a common pathway that regulates dopaminergic neuron survival. PINK1 interacts with and phosphorylates serines 322 and 613 of PARIS to control its ubiquitination and clearance by parkin. PINK1 phosphorylation of PARIS alleviates PARIS toxicity, as well as repression of PGC-1α promoter activity. Conditional knockdown of PINK1 in adult mouse brains leads to a progressive loss of dopaminergic neurons in the substantia nigra that is dependent on PARIS. Altogether, these results uncover a function of PINK1 to direct parkin-PARIS-regulated PGC-1α expression and dopaminergic neuronal survival. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Phospho-ubiquitin: upending the PINK-Parkin-ubiquitin cascade.

PubMed

Matsuda, Noriyuki

2016-04-01

Mitochondria with decreased membrane potential are characterized by defects in protein import into the matrix and impairments in high-efficiency synthesis of ATP. These low-quality mitochondria are marked with ubiquitin for selective degradation. Key factors in this mechanism are PTEN-induced putative kinase 1 (PINK1, a mitochondrial kinase) and Parkin (a ubiquitin ligase), disruption of which has been implicated in predisposition to Parkinson's disease. Previously, the clearance of damaged mitochondria had been thought to be the end result of a simple cascading reaction of PINK1-Parkin-ubiquitin. However, in the past year, several research groups including ours unexpectedly revealed that Parkin regulation is mediated by PINK1-dependent phosphorylation of ubiquitin. These results overturned the simple hierarchy that posited PINK1 and ubiquitin as the upstream and downstream factors of Parkin, respectively. Although ubiquitylation is well-known as a post-translational modification, it has recently become clear that ubiquitin itself can be modified, and that this modification unexpectedly converts ubiquitin to a factor that functions in retrograde signalling. © The Authors 2016. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Olfaction in Parkin single and compound heterozygotes in a cohort of young onset Parkinson's disease patients.

PubMed

Malek, N; Swallow, D M A; Grosset, K A; Lawton, M A; Smith, C R; Bajaj, N P; Barker, R A; Ben-Shlomo, Y; Bresner, C; Burn, D J; Foltynie, T; Morris, H R; Williams, N; Wood, N W; Grosset, D G

2016-10-01

Parkin related Parkinson's disease (PD) is differentiated from idiopathic PD by absent or sparse Lewy bodies, and preserved olfaction. The significance of single Parkin mutations in the pathogenesis of PD is debated. To assess olfaction results according to Parkin mutation status. To compare the prevalence of Parkin single heterozygous mutations in patients diagnosed with PD to the rate in healthy controls in order to establish whether these single mutations could be a risk factor for developing PD. Parkin gene mutation testing was performed in young onset PD (diagnosed <50 years old) to identify three groups: Parkin homozygous or compound heterozygote mutation carriers, Parkin single heterozygote mutation carriers, and non-carriers of Parkin mutations. Olfaction was tested using the 40-item British version of the University of Pennsylvania smell identification test (UPSIT). Of 344 young onset PD cases tested, 8 (2.3%) were Parkin compound heterozygotes and 13 (3.8%) were Parkin single heterozygotes. Olfaction results were available in 282 cases (eight compound heterozygotes, nine single heterozygotes, and 265 non-carriers). In Parkin compound heterozygotes, the median UPSIT score was 33, interquartile range (IQR) 28.5-36.5, which was significantly better than in single Parkin heterozygotes (median 19, IQR 18-28) and non-carriers (median score 22, IQR 16-28) (ANOVA P < 0.001). These differences persisted after adjusting for age, disease duration, gender, and smoking (P < 0.001). There was no significant difference in UPSIT scores between single heterozygotes and non-carriers (P = 0.90). Patients with Parkin compound heterozygous mutations have relatively preserved olfaction compared to Parkin single heterozygotes and non-carriers. The prevalence of Parkin single heterozygosity is similar to the 3.7% rate reported in healthy controls. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Parkin negatively regulates the antiviral signaling pathway by targeting TRAF3 for degradation.

PubMed

Xin, Di; Gu, Haiyan; Liu, Enping; Sun, Qinmiao

2018-06-14

Chronic neuroinflammation is a characteristic of Parkinson's disease (PD). Previous investigations have shown that Parkin gene mutations are related to the early-onset recessive form of PD and isolated juvenile-onset PD. Further, Parkin plays important roles in mitochondrial quality control and cytokine-induced cell death. However, whether Parkin regulates other cellular events is still largely unknown. In this study, we performed overexpression and knockout experiments, and found that Parkin negatively regulates antiviral immune responses against RNA and DNA viruses. Mechanistically, we show that Parkin interacts with tumor necrosis factor receptor-associated factor 3 (TRAF3) to regulate stability of TRAF3 protein by promoting K48-linked ubiquitination. Our findings suggest that Parkin plays a novel role in innate immune signaling by targeting TRAF3 for degradation, and maintaining the balance of innate antiviral immunity. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Parkin is required for exercise-induced mitophagy in muscle: impact of aging.

PubMed

Chen, Chris Chin Wah; Erlich, Avigail T; Crilly, Matthew J; Hood, David A

2018-05-29

The maintenance of muscle health with advancing age is dependent on mitochondrial homeostasis. While reductions in mitochondrial biogenesis have been observed with age, less is known regarding organelle degradation. Parkin is an E3 ubiquitin ligase implicated in mitophagy, but few studies have examined Parkin's contribution to mitochondrial turnover in muscle. Wild type (WT) and Parkin knockout (KO) mice were used to delineate a role for Parkin-mediated mitochondrial degradation in aged muscle, in concurrence with exercise. Aged animals exhibited declines in muscle mass and mitochondrial content, paralleled by a nuclear environment endorsing the transcriptional repression of mitochondrial biogenesis. Mitophagic signaling was enhanced following acute endurance exercise in young WT mice, but was abolished in the absence of Parkin. Basal mitophagy flux of the autophagosomal protein LC3II was augmented in aged animals, but did not increase additionally with exercise when compared to young animals. In the absence of Parkin, exercise increased the nuclear localization of PARIS, corresponding to a decrease in nuclear PGC-1α. Remarkably, exercise enhanced mitochondrial ubiquitination in both young WT and KO animals. This suggested compensation of alternative ubiquitin ligases that were, however, unable to restore the diminished exercise-induced mitophagy in KO mice. Under basal conditions, we demonstrated that Parkin was required for mitochondrial Mfn2 ubiquitination. We also observed an abrogation of exercise-induced mitophagy in aged muscle. Our results demonstrate that acute exercise-induced mitophagy is dependent on Parkin, and attenuated with age, which likely contributes to changes in mitochondrial content and quality in aging muscle.

Binding to serine 65-phosphorylated ubiquitin primes Parkin for optimal PINK1-dependent phosphorylation and activation

PubMed Central

Kazlauskaite, Agne; Martínez-Torres, R Julio; Wilkie, Scott; Kumar, Atul; Peltier, Julien; Gonzalez, Alba; Johnson, Clare; Zhang, Jinwei; Hope, Anthony G; Peggie, Mark; Trost, Matthias; van Aalten, Daan MF; Alessi, Dario R; Prescott, Alan R; Knebel, Axel; Walden, Helen; Muqit, Miratul MK

2015-01-01

Mutations in the mitochondrial protein kinase PINK1 are associated with autosomal recessive Parkinson disease (PD). We and other groups have reported that PINK1 activates Parkin E3 ligase activity both directly via phosphorylation of Parkin serine 65 (Ser65)—which lies within its ubiquitin-like domain (Ubl)—and indirectly through phosphorylation of ubiquitin at Ser65. How Ser65-phosphorylated ubiquitin (ubiquitinPhospho-Ser65) contributes to Parkin activation is currently unknown. Here, we demonstrate that ubiquitinPhospho-Ser65 binding to Parkin dramatically increases the rate and stoichiometry of Parkin phosphorylation at Ser65 by PINK1 in vitro. Analysis of the Parkin structure, corroborated by site-directed mutagenesis, shows that the conserved His302 and Lys151 residues play a critical role in binding of ubiquitinPhospho-Ser65, thereby promoting Parkin Ser65 phosphorylation and activation of its E3 ligase activity in vitro. Mutation of His302 markedly inhibits Parkin Ser65 phosphorylation at the mitochondria, which is associated with a marked reduction in its E3 ligase activity following mitochondrial depolarisation. We show that the binding of ubiquitinPhospho-Ser65 to Parkin disrupts the interaction between the Ubl domain and C-terminal region, thereby increasing the accessibility of Parkin Ser65. Finally, purified Parkin maximally phosphorylated at Ser65 in vitro cannot be further activated by the addition of ubiquitinPhospho-Ser65. Our results thus suggest that a major role of ubiquitinPhospho-Ser65 is to promote PINK1-mediated phosphorylation of Parkin at Ser65, leading to maximal activation of Parkin E3 ligase activity. His302 and Lys151 are likely to line a phospho-Ser65-binding pocket on the surface of Parkin that is critical for the ubiquitinPhospho-Ser65 interaction. This study provides new mechanistic insights into Parkin activation by ubiquitinPhospho-Ser65, which could aid in the development of Parkin activators that mimic the effect of

Binding to serine 65-phosphorylated ubiquitin primes Parkin for optimal PINK1-dependent phosphorylation and activation.

PubMed

Kazlauskaite, Agne; Martínez-Torres, R Julio; Wilkie, Scott; Kumar, Atul; Peltier, Julien; Gonzalez, Alba; Johnson, Clare; Zhang, Jinwei; Hope, Anthony G; Peggie, Mark; Trost, Matthias; van Aalten, Daan M F; Alessi, Dario R; Prescott, Alan R; Knebel, Axel; Walden, Helen; Muqit, Miratul M K

2015-08-01

Mutations in the mitochondrial protein kinase PINK1 are associated with autosomal recessive Parkinson disease (PD). We and other groups have reported that PINK1 activates Parkin E3 ligase activity both directly via phosphorylation of Parkin serine 65 (Ser(65))--which lies within its ubiquitin-like domain (Ubl)--and indirectly through phosphorylation of ubiquitin at Ser(65). How Ser(65)-phosphorylated ubiquitin (ubiquitin(Phospho-Ser65)) contributes to Parkin activation is currently unknown. Here, we demonstrate that ubiquitin(Phospho-Ser65) binding to Parkin dramatically increases the rate and stoichiometry of Parkin phosphorylation at Ser(65) by PINK1 in vitro. Analysis of the Parkin structure, corroborated by site-directed mutagenesis, shows that the conserved His302 and Lys151 residues play a critical role in binding of ubiquitin(Phospho-Ser65), thereby promoting Parkin Ser(65) phosphorylation and activation of its E3 ligase activity in vitro. Mutation of His302 markedly inhibits Parkin Ser(65) phosphorylation at the mitochondria, which is associated with a marked reduction in its E3 ligase activity following mitochondrial depolarisation. We show that the binding of ubiquitin(Phospho-Ser65) to Parkin disrupts the interaction between the Ubl domain and C-terminal region, thereby increasing the accessibility of Parkin Ser(65). Finally, purified Parkin maximally phosphorylated at Ser(65) in vitro cannot be further activated by the addition of ubiquitin(Phospho-Ser65). Our results thus suggest that a major role of ubiquitin(Phospho-Ser65) is to promote PINK1-mediated phosphorylation of Parkin at Ser(65), leading to maximal activation of Parkin E3 ligase activity. His302 and Lys151 are likely to line a phospho-Ser(65)-binding pocket on the surface of Parkin that is critical for the ubiquitin(Phospho-Ser65) interaction. This study provides new mechanistic insights into Parkin activation by ubiquitin(Phospho-Ser65), which could aid in the development of Parkin

Parkin, A Top Level Manager in the Cell’s Sanitation Department

PubMed Central

Rankin, Carolyn A; Roy, Ambrish; Zhang, Yang; Richter, Mark

2011-01-01

Parkin belongs to a class of multiple RING domain proteins designated as RBR (RING, in between RING, RING) proteins. In this review we examine what is known regarding the structure/function relationship of the Parkin protein. Parkin contains three RING domains plus a ubiquitin-like domain and an in-between-RING (IBR) domain. RING domains are rich in cysteine amino acids that act as ligands to bind zinc ions. RING domains may interact with DNA or with other proteins and perform a wide range of functions. Some function as E3 ubiquitin ligases, participating in attachment of ubiquitin chains to signal proteasome degradation; however, ubiquitin may be attached for purposes other than proteasome degradation. It was determined that the C-terminal most RING, RING2, is essential for Parkin to function as an E3 ubiquitin ligase and a number of substrates have been identified. However, Parkin also participates in a number of other fiunctions, such as DNA repair, microtubule stabilization, and formation of aggresomes. Some functions, such as participation in a multi-protein complex implicated in NMDA activity at the post synaptic density, do not require ubiquitination of substrate molecules. Recent observations of RING proteins suggest their function may be regulated by zinc ion binding. We have modeled the three RING domains of Parkin and have identified a new set of RING2 ligands. This set allows for binding of two rather than just one zinc ion, opening the possibility that the number of zinc ions bound acts as a molecular switch to modulate Parkin function. PMID:21633666

Parkin-mediated protection of dopaminergic neurons in a chronic MPTP-minipump mouse model of Parkinson disease.

PubMed

Yasuda, Toru; Hayakawa, Hideki; Nihira, Tomoko; Ren, Yong-Ri; Nakata, Yasuto; Nagai, Makiko; Hattori, Nobutaka; Miyake, Koichi; Takada, Masahiko; Shimada, Takashi; Mizuno, Yoshikuni; Mochizuki, Hideki

2011-08-01

Loss-of-function mutations in the ubiquitin ligase parkin are the major cause of recessively inherited early-onset Parkinson disease (PD). Impairment of parkin activity caused by nitrosative or dopamine-related modifications may also be responsible for the loss of dopaminergic (DA) neurons in sporadic PD. Previous studies have shown that viral vector-mediated delivery of parkin prevented DA neurodegeneration in several animal models, but little is known about the neuroprotective actions of parkin in vivo. Here, we investigated mechanisms of neuroprotection of overexpressed parkin in a modified long-term mouse model of PD using osmotic minipump administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Recombinant adeno-associated viral vector-mediated intranigral delivery of parkin prevented motor deficits and DA cell loss in the mice. Ser129-phosphorylated α-synuclein-immunoreactive cells were increased in the substantia nigra of parkin-treated mice. Moreover, delivery of parkin alleviated the MPTP-induced decrease of the active phosphorylated form of Akt. On the other hand, upregulation of p53 and mitochondrial alterations induced by chronic MPTP administration were barely suppressed by parkin. These results suggest that the neuroprotective actions of parkin may be impaired in severe PD.

High expression of Parkin predicts easier recurrence of patients with adjuvant transarterial chemoembolization.

PubMed

Zhang, Changlie; Song, Zhihong; Yu, Guangji

2017-10-01

To investigate the clinical significance of E3 ubiquitin ligase Parkin in patients with adjuvant transarterial chemoembolization after curative resection of hepatocellular carcinoma. Parkin expression of hepatocellular carcinomas was detected and its correlation with clinicopathological factors was analyzed with χ 2 test. The significance of Parkin in prognosis and recurrence was analyzed with log-rank test and the Cox-regression model. High expression of Parkin could result in lower recurrence-free survival rate instead of overall survival rate. Larger tumor size, positive tumor recurrence, advanced T, N, M and TNM stage were significantly associated with poorer prognosis. Larger tumor size, advanced T and TNM stage could lead to higher recurrence. High Parkin expression could predict easier recurrence to patients with adjuvant transarterial chemoembolization.

Loss of Parkin reduces inflammatory arthritis by inhibiting p53 degradation.

PubMed

Jung, Yu Yeon; Son, Dong Ju; Lee, Hye Lim; Kim, Dae Hwan; Song, Min Jong; Ham, Young Wan; Kim, Youngsoo; Han, Sang Bae; Park, Mi Hee; Hong, Jin Tae

2017-08-01

Parkin is associated with various inflammatory diseases, including Parkinson's disease (PD) and rheumatoid arthritis (RA). However, the precise role of Parkin in RA is unclear. The present study addressed this issue by comparing the development of RA between non-transgenic (non-Tg) mice and PARK2 knockout (KO) mice. We found that cyclooxygenase-2 and inducible nitric oxide synthase expression and nuclear factor-κB activity were reduced but p53 activation was increased in PARK2 KO as compared to non-Tg mice. These effects were associated with reduced p53 degradation. Parkin was found to interact with p53; however, this was abolished in Parkin KO mice, which prevented p53 degradation. Treatment of PARK2 KO mice with p53 inhibitor increased Parkin expression as well as inflammation and RA development while decreasing nuclear p53 translocation, demonstrating that PARK2 deficiency inhibits inflammation in RA via suppression of p53 degradation. These results suggest that RA development may be reduced in PD patients. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Lead (Pb) induced ATM-dependent mitophagy via PINK1/Parkin pathway.

PubMed

Gu, Xueyan; Qi, Yongmei; Feng, Zengxiu; Ma, Lin; Gao, Ke; Zhang, Yingmei

2018-07-01

Lead (Pb), a widely distributed environmental pollutant, is known to induce mitochondrial damage as well as autophagy in vitro and in vivo. In this study, we found that Pb could trigger mitophagy in both HEK293 cells and the kidney cortex of male Kunming mice. However, whether ataxia telangiectasis mutated (ATM) which is reported to be linked with PTEN-induced putative kinase 1 (PINK1)/Parkin pathway (a well-characterized mitophagic pathway) participates in the regulation of Pb-induced mitophagy and its exact role remains enigmatic. Our results indicated that Pb activated ATM in vitro and in vivo, and further in vitro studies showed that ATM could co-localize with PINK1 and Parkin in cytosol and interact with PINK1. Knockdown of ATM by siRNA blocked Pb-induced mitophagy even under the circumstance of enhanced accumulation of PINK1 and mitochondrial Parkin. Intriguingly, elevation instead of reduction in phosphorylation level of PINK1 and Parkin was observed in response to ATM knockdown and Pb did not contribute to the further increase of their phosphorylation level, implying that ATM indirectly regulated PINK1/Parkin pathway. These findings reveal a novel mechanism for Pb toxicity and suggest the regulatory importance of ATM in PINK1/Parkin-mediated mitophagy. Copyright © 2018 Elsevier B.V. All rights reserved.

Cell-Permeable Parkin Proteins Suppress Parkinson Disease-Associated Phenotypes in Cultured Cells and Animals

PubMed Central

Duong, Tam; Kim, Jaetaek; Ruley, H. Earl; Jo, Daewoong

2014-01-01

Parkinson’s disease (PD) is a neurodegenerative disorder of complex etiology characterized by the selective loss of dopaminergic neurons, particularly in the substantia nigra. Parkin, a tightly regulated E3 ubiquitin ligase, promotes the survival of dopaminergic neurons in both PD and Parkinsonian syndromes induced by acute exposures to neurotoxic agents. The present study assessed the potential of cell-permeable parkin (CP-Parkin) as a neuroprotective agent. Cellular uptake and tissue penetration of recombinant, enzymatically active parkin was markedly enhanced by the addition of a hydrophobic macromolecule transduction domain (MTD). The resulting CP-Parkin proteins (HPM13 and PM10) suppressed dopaminergic neuronal toxicity in cells and mice exposed to 6-hydroxydopamine (6-OHDH) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). These included enhanced survival and dopamine expression in cultured CATH.a and SH-SY5Y neuronal cells; and protection against MPTP-induced damage in mice, notably preservation of tyrosine hydroxylase-positive cells with enhanced dopamine expression in the striatum and midbrain, and preservation of gross motor function. These results demonstrate that CP-Parkin proteins can compensate for intrinsic limitations in the parkin response and provide a therapeutic strategy to augment parkin activity in vivo. PMID:25019626

PINK1-dependent phosphorylation of PINK1 and Parkin is essential for mitochondrial quality control.

PubMed

Zhuang, Na; Li, Lin; Chen, She; Wang, Tao

2016-12-01

Mitochondrial dysfunction has been linked to the pathogenesis of a large number of inherited diseases in humans, including Parkinson's disease, the second most common neurodegenerative disorder. The Parkinson's disease genes pink1 and parkin, which encode a mitochondrially targeted protein kinase, and an E3 ubiquitin ligase, respectively, participate in a key mitochondrial quality-control pathway that eliminates damaged mitochondria. In the current study, we established an in vivo PINK1/Parkin-induced photoreceptor neuron degeneration model in Drosophila with the aim of dissecting the PINK1/Parkin pathway in detail. Using LC-MS/MS analysis, we identified Serine 346 as the sole autophosphorylation site of Drosophila PINK1 and found that substitution of Serine 346 to Alanine completely abolished the PINK1 autophosphorylation. Disruption of either PINK1 or Parkin phosphorylation impaired the PINK1/Parkin pathway, and the degeneration phenotype of photoreceptor neurons was obviously alleviated. Phosphorylation of PINK1 is not only required for the PINK1-mediated mitochondrial recruitment of Parkin but also induces its kinase activity toward Parkin. In contrast, phosphorylation of Parkin by PINK1 is dispensable for its translocation but required for its activation. Moreover, substitution with autophosphorylation-deficient PINK1 failed to rescue pink1 null mutant phenotypes. Taken together, our findings suggest that autophosphorylation of PINK1 is essential for the mitochondrial translocation of Parkin and for subsequent phosphorylation and activation of Parkin.

Parkin is a lipid-responsive regulator of fat uptake in mice and mutant human cells

PubMed Central

Kim, Kye-Young; Stevens, Mark V.; Akter, M. Hasina; Rusk, Sarah E.; Huang, Robert J.; Cohen, Alexandra; Noguchi, Audrey; Springer, Danielle; Bocharov, Alexander V.; Eggerman, Tomas L.; Suen, Der-Fen; Youle, Richard J.; Amar, Marcelo; Remaley, Alan T.; Sack, Michael N.

2011-01-01

It has long been hypothesized that abnormalities in lipid biology contribute to degenerative brain diseases. Consistent with this, emerging epidemiologic evidence links lipid alterations with Parkinson disease (PD), and disruption of lipid metabolism has been found to predispose to α-synuclein toxicity. We therefore investigated whether Parkin, an E3 ubiquitin ligase found to be defective in patients with early onset PD, regulates systemic lipid metabolism. We perturbed lipid levels by exposing Parkin+/+ and Parkin–/– mice to a high-fat and -cholesterol diet (HFD). Parkin–/– mice resisted weight gain, steatohepatitis, and insulin resistance. In wild-type mice, the HFD markedly increased hepatic Parkin levels in parallel with lipid transport proteins, including CD36, Sr-B1, and FABP. These lipid transport proteins were not induced in Parkin–/– mice. The role of Parkin in fat uptake was confirmed by increased oleate accumulation in hepatocytes overexpressing Parkin and decreased uptake in Parkin–/– mouse embryonic fibroblasts and patient cells harboring complex heterozygous mutations in the Parkin-encoding gene PARK2. Parkin conferred this effect, in part, via ubiquitin-mediated stabilization of the lipid transporter CD36. Reconstitution of Parkin restored hepatic fat uptake and CD36 levels in Parkin–/– mice, and Parkin augmented fat accumulation during adipocyte differentiation. These results demonstrate that Parkin is regulated in a lipid-dependent manner and modulates systemic fat uptake via ubiquitin ligase–dependent effects. Whether this metabolic regulation contributes to premature Parkinsonism warrants investigation. PMID:21865652

PINK1-dependent phosphorylation of PINK1 and Parkin is essential for mitochondrial quality control

PubMed Central

Zhuang, Na; Li, Lin; Chen, She; Wang, Tao

2016-01-01

Mitochondrial dysfunction has been linked to the pathogenesis of a large number of inherited diseases in humans, including Parkinson's disease, the second most common neurodegenerative disorder. The Parkinson's disease genes pink1 and parkin, which encode a mitochondrially targeted protein kinase, and an E3 ubiquitin ligase, respectively, participate in a key mitochondrial quality-control pathway that eliminates damaged mitochondria. In the current study, we established an in vivo PINK1/Parkin-induced photoreceptor neuron degeneration model in Drosophila with the aim of dissecting the PINK1/Parkin pathway in detail. Using LC-MS/MS analysis, we identified Serine 346 as the sole autophosphorylation site of Drosophila PINK1 and found that substitution of Serine 346 to Alanine completely abolished the PINK1 autophosphorylation. Disruption of either PINK1 or Parkin phosphorylation impaired the PINK1/Parkin pathway, and the degeneration phenotype of photoreceptor neurons was obviously alleviated. Phosphorylation of PINK1 is not only required for the PINK1-mediated mitochondrial recruitment of Parkin but also induces its kinase activity toward Parkin. In contrast, phosphorylation of Parkin by PINK1 is dispensable for its translocation but required for its activation. Moreover, substitution with autophosphorylation-deficient PINK1 failed to rescue pink1 null mutant phenotypes. Taken together, our findings suggest that autophosphorylation of PINK1 is essential for the mitochondrial translocation of Parkin and for subsequent phosphorylation and activation of Parkin. PMID:27906179

The Roles of PINK1, Parkin and Mitochondrial Fidelity in Parkinson's Disease

PubMed Central

Pickrell, Alicia M.; Youle, Richard J.

2015-01-01

Understanding the function of genes mutated in hereditary forms of Parkinson's disease yields insight into disease etiology and reveals new pathways in cell biology. Although mutations or variants in many genes increase the susceptibility to Parkinson's disease, only a handful of monogenic causes of Parkinsonism have been identified. Biochemical and genetic studies reveal that the products of two genes that are mutated in autosomal recessive Parkinsonism, PINK1 and Parkin, normally work together in the same pathway to govern mitochondrial quality control, bolstering previous evidence that mitochondrial damage is involved in Parkinson's disease. PINK1 accumulates on the outer membrane of damaged mitochondria, activates Parkin's E3 ubiquitin ligase activity and recruits Parkin to the dysfunctional mitochondrion. Then, Parkin ubiquitinates outer mitochondrial membrane proteins to trigger selective autophagy. This review covers the normal functions that PINK1 and Parkin play within cells, their molecular mechanisms of action, and the pathophysiological consequences of their loss. PMID:25611507

Parkin protein expression and its impact on survival of patients with advanced colorectal cancer.

PubMed

da Silva-Camargo, Claudia Caroline Veloso; Svoboda Baldin, Rosimeri Kuhl; Costacurta Polli, Nayanne Louise; Agostinho, Amanda Pereira; Olandosk, Marcia; de Noronha, Lúcia; Sotomaior, Vanessa Santos

2018-02-01

Features of colorectal cancer such as natural history, molecular, chromosomal, and epigenetic alterations have been well described. However, there is still a lack of accurate prognostic markers, which is evident by the lower overall survival rates of patients with advanced cancer. Although alterations in parkin protein expression have been described in colorectal cancer, the functional significance of this protein remains unknown. The present study aimed to investigate the involvement of parkin expression in colorectal adenocarcinoma development and progression by evaluating the association between its expression, clinicopathological parameters, and expression of known proteins involved in colorectal cancer. Tissue microarrays consisting of 73 tumor and 64 normal tissue samples were generated to examine parkin expression and localization by immunohistochemistry. A positive correlation of parkin and APC expression was observed in the superficial, intermediate, and profound regions of all cases (ρ = 0.37; P = 0.001). Parkin expression was also significantly associated with tumors in men ( P = 0.049), those of the mucinous subtype ( P = 0.028), and of advanced stage (III + IV, P = 0.041). In addition, increased parkin expression was observed in the invasive front tumor region ( P = 0.013). More importantly, a positive correlation was found between parkin expression and the overall survival of patients with advanced colorectal cancer ( P = 0.019). Multivariate analysis showed that parkin expression was independent of any of the clinicopathological parameters evaluated in relation to patient survival. These results suggest that parkin expression status can be used as a potential independent prognostic marker of survival in advanced colorectal cancer.

Protective role of Parkin in skeletal muscle contractile and mitochondrial function.

PubMed

Gouspillou, Gilles; Godin, Richard; Piquereau, Jérome; Picard, Martin; Mofarrahi, Mahroo; Mathew, Jasmin; Purves-Smith, Fennigje M; Sgarioto, Nicolas; Hepple, Russell T; Burelle, Yan; Hussain, Sabah N A

2018-04-22

Parkin, an E3 ubiquitin ligase encoded by the Park2 gene, has been implicated in the regulation of mitophagy, a quality control process in which defective mitochondria are degraded. The exact physiological significance of Parkin in regulating mitochondrial function and contractility in skeletal muscle remains largely unexplored. Using Park2 -/- mice, we show that Parkin ablation causes a decrease in muscle specific force, a severe decrease in mitochondrial respiration, mitochondrial uncoupling and an increased susceptibility to opening of the permeability transition pore. These results demonstrate that Parkin plays a protective role in the maintenance of normal mitochondrial and contractile functions in skeletal muscles. Parkin is an E3 ubiquitin ligase encoded by the Park2 gene. Parkin has been implicated in the regulation of mitophagy, a quality control process in which defective mitochondria are sequestered in autophagosomes and delivered to lysosomes for degradation. Although Parkin has been mainly studied for its implication in neuronal degeneration in Parkinson disease, its role in other tissues remains largely unknown. In the present study, we investigated the skeletal muscles of Park2 knockout (Park2 -/- ) mice to test the hypothesis that Parkin plays a physiological role in mitochondrial quality control in normal skeletal muscle, a tissue highly reliant on mitochondrial content and function. We first show that the tibialis anterior (TA) of Park2 -/- mice display a slight but significant decrease in its specific force. Park2 -/ - muscles also show a trend for type IIB fibre hypertrophy without alteration in muscle fibre type proportion. Compared to Park2 +/+ muscles, the mitochondrial function of Park2 -/- skeletal muscles was significantly impaired, as indicated by the significant decrease in ADP-stimulated mitochondrial respiratory rates, uncoupling, reduced activities of respiratory chain complexes containing mitochondrial DNA (mtDNA)-encoded subunits

Parkin-phosphoubiquitin complex reveals a cryptic ubiquitin binding site required for RBR ligase activity

PubMed Central

Kumar, Atul; Chaugule, Viduth K; Condos, Tara E C; Barber, Kathryn R; Johnson, Clare; Toth, Rachel; Sundaramoorthy, Ramasubramanian; Knebel, Axel; Shaw, Gary S; Walden, Helen

2017-01-01

RING-BETWEENRING-RING (RBR) E3 ligases are a class of ubiquitin ligases distinct from RING or HECT E3 ligases. An important RBR is Parkin, mutations in which lead to early onset hereditary Parkinsonism. Parkin and other RBRs share a catalytic RBR module, but are usually autoinhibited and activated via distinct mechanisms. Recent insights into Parkin regulation predict large, unknown conformational changes during activation of Parkin. However, current data on active RBRs are in the absence of regulatory domains. Therefore, how individual RBRs are activated, and whether they share a common mechanism remains unclear. We now report the crystal structure of a human Parkin-phosphoubiquitin complex, which shows that phosphoubiquitin binding induces a movement in the IBR domain to reveal a cryptic ubiquitin binding site. Mutation of this site negatively impacts on Parkin’s activity. Furthermore, ubiquitin binding promotes cooperation between Parkin molecules, suggesting a role for interdomain association in RBR ligase mechanism. PMID:28414322

Murine Endogenous Retroviruses Are Detectable in Patient-Derived Xenografts but Not in Patient-Individual Cell Lines of Human Colorectal Cancer.

PubMed

Bock, Stephanie; Mullins, Christina S; Klar, Ernst; Pérot, Philippe; Maletzki, Claudia; Linnebacher, Michael

2018-01-01

Endogenous retroviruses are remnants of retroviral infections. In contrast to their human counterparts, murine endogenous retroviruses (mERV) still can synthesize infectious particles and retrotranspose. Xenotransplanted human cells have occasionally been described to be mERV infected. With genetic engineered mice and patient-derived xenografts (PDXs) on the rise as eminent research tools, we here systematically investigated, if different tumor models harbor mERV infections. Relevant mERV candidates were first preselected by next generation sequencing (NGS) analysis of spontaneous lymphomas triggered by colorectal cancer (CRC) PDX tissue. Two primer systems were designed for each of these candidates (AblMLV, EcoMLV, EndoPP, MLV, and preXMRV) and implemented in an quantitative real-time (RT-qPCR) screen using murine tissues ( n = 11), PDX-tissues ( n = 22), PDX-derived cell lines ( n = 13), and patient-derived tumor cell lines ( n = 14). The expression levels of mERV varied largely both in the PDX samples and in the mouse tissues. No mERV signal was, however, obtained from cDNA or genomic DNA of CRC cell lines. Expression of EcoMLV was higher in PDX than in murine tissues; for EndoPP it was the opposite. These two were thus further investigated in 40 additional PDX. In addition, four patient-derived cell lines free of any mERV expression were subcutaneously injected into immunodeficient mice. Outgrowing cell-derived xenografts barely expressed EndoPP. In contrast, the expression of EcoMLV was even higher than in surrounding mouse tissues. This expression gradually vanished within few passages of re-cultivated cells. In summary, these results strongly imply that: (i) PDX and murine tissues in general are likely to be contaminated by mERV, (ii) mERV are expressed transiently and at low level in fresh PDX-derived cell cultures, and (iii) mERV integration into the genome of human cells is unlikely or at least a very rare event. Thus, mERVs are stowaways present in

Compartmentalized Regulation of Parkin-Mediated Mitochondrial Quality Control in the Drosophila Nervous System In Vivo.

PubMed

Sung, Hyun; Tandarich, Lauren C; Nguyen, Kenny; Hollenbeck, Peter J

2016-07-13

In neurons, the normal distribution and selective removal of mitochondria are considered essential for maintaining the functions of the large asymmetric cell and its diverse compartments. Parkin, a E3 ubiquitin ligase associated with familial Parkinson's disease, has been implicated in mitochondrial dynamics and removal in cells including neurons. However, it is not clear how Parkin functions in mitochondrial turnover in vivo, or whether Parkin-dependent events of the mitochondrial life cycle occur in all neuronal compartments. Here, using the live Drosophila nervous system, we investigated the involvement of Parkin in mitochondrial dynamics, distribution, morphology, and removal. Contrary to our expectations, we found that Parkin-deficient animals do not accumulate senescent mitochondria in their motor axons or neuromuscular junctions; instead, they contain far fewer axonal mitochondria, and these displayed normal motility behavior, morphology, and metabolic state. However, the loss of Parkin did produce abnormal tubular and reticular mitochondria restricted to the motor cell bodies. In addition, in contrast to drug-treated, immortalized cells in vitro, mature motor neurons rarely displayed Parkin-dependent mitophagy. These data indicate that the cell body is the focus of Parkin-dependent mitochondrial quality control in neurons, and argue that a selection process allows only healthy mitochondria to pass from cell bodies to axons, perhaps to limit the impact of mitochondrial dysfunction. Parkin has been proposed to police mitochondrial fidelity by binding to dysfunctional mitochondria via PTEN (phosphatase and tensin homolog)-induced putative kinase 1 (PINK1) and targeting them for autophagic degradation. However, it is unknown whether and how the PINK1/Parkin pathway regulates the mitochondrial life cycle in neurons in vivo Using Drosophila motor neurons, we show that parkin disruption generates an abnormal mitochondrial network in cell bodies in vivo and reduces

Compartmentalized Regulation of Parkin-Mediated Mitochondrial Quality Control in the Drosophila Nervous System In Vivo

PubMed Central

Sung, Hyun; Tandarich, Lauren C.; Nguyen, Kenny

2016-01-01

In neurons, the normal distribution and selective removal of mitochondria are considered essential for maintaining the functions of the large asymmetric cell and its diverse compartments. Parkin, a E3 ubiquitin ligase associated with familial Parkinson's disease, has been implicated in mitochondrial dynamics and removal in cells including neurons. However, it is not clear how Parkin functions in mitochondrial turnover in vivo, or whether Parkin-dependent events of the mitochondrial life cycle occur in all neuronal compartments. Here, using the live Drosophila nervous system, we investigated the involvement of Parkin in mitochondrial dynamics, distribution, morphology, and removal. Contrary to our expectations, we found that Parkin-deficient animals do not accumulate senescent mitochondria in their motor axons or neuromuscular junctions; instead, they contain far fewer axonal mitochondria, and these displayed normal motility behavior, morphology, and metabolic state. However, the loss of Parkin did produce abnormal tubular and reticular mitochondria restricted to the motor cell bodies. In addition, in contrast to drug-treated, immortalized cells in vitro, mature motor neurons rarely displayed Parkin-dependent mitophagy. These data indicate that the cell body is the focus of Parkin-dependent mitochondrial quality control in neurons, and argue that a selection process allows only healthy mitochondria to pass from cell bodies to axons, perhaps to limit the impact of mitochondrial dysfunction. SIGNIFICANCE STATEMENT Parkin has been proposed to police mitochondrial fidelity by binding to dysfunctional mitochondria via PTEN (phosphatase and tensin homolog)-induced putative kinase 1 (PINK1) and targeting them for autophagic degradation. However, it is unknown whether and how the PINK1/Parkin pathway regulates the mitochondrial life cycle in neurons in vivo. Using Drosophila motor neurons, we show that parkin disruption generates an abnormal mitochondrial network in cell

Parkin dosage mutations have greater pathogenicity in familial PD than simple sequence mutations

PubMed Central

Pankratz, N; Kissell, D K.; Pauciulo, M W.; Halter, C A.; Rudolph, A; Pfeiffer, R F.; Marder, K S.; Foroud, T; Nichols, W C.

2009-01-01

Objective: Mutations in both alleles of parkin have been shown to result in Parkinson disease (PD). However, it is unclear whether haploinsufficiency (presence of a mutation in only 1 of the 2 parkin alleles) increases the risk for PD. Methods: We performed comprehensive dosage and sequence analysis of all 12 exons of parkin in a sample of 520 independent patients with familial PD and 263 controls. We evaluated whether presence of a single parkin mutation, either a sequence (point mutation or small insertion/deletion) or dosage (whole exon deletion or duplication) mutation, was found at increased frequency in cases as compared with controls. We then compared the clinical characteristics of cases with 0, 1, or 2 parkin mutations. Results: We identified 55 independent patients with PD with at least 1 parkin mutation and 9 controls with a single sequence mutation. Cases and controls had a similar frequency of single sequence mutations (3.1% vs 3.4%, p = 0.83); however, the cases had a significantly higher rate of dosage mutations (2.6% vs 0%, p = 0.009). Cases with a single dosage mutation were more likely to have an earlier age at onset (50% with onset at ≤45 years) compared with those with no parkin mutations (10%, p = 0.00002); this was not true for cases with only a single sequence mutation (25% with onset at ≤45 years, p = 0.06). Conclusions: Parkin haploinsufficiency, specifically for a dosage mutation rather than a point mutation or small insertion/deletion, is a risk factor for familial PD and may be associated with earlier age at onset. GLOSSARY ADL = Activities of Daily Living; GDS = Geriatric Depression Scale; MLPA = multiplex ligation-dependent probe amplification; MMSE = Mini-Mental State Examination; PD = Parkinson disease; UPDRS = Unified Parkinson’s Disease Rating Scale. PMID:19636047

Nix restores mitophagy and mitochondrial function to protect against PINK1/Parkin-related Parkinson's disease.

PubMed

Koentjoro, Brianada; Park, Jin-Sung; Sue, Carolyn M

2017-03-10

Therapeutic targets are needed to develop neuroprotective treatments for Parkinson's disease (PD). Mitophagy, the selective autophagic elimination of dysfunctional mitochondria, is essential for the maintenance of mitochondrial integrity and is predominantly regulated by the PINK1/Parkin-mediated pathway. Loss of function mutations in Parkin and PINK1 cause an accumulation of dysfunctional mitochondria, leading to nigral neurodegeneration and early-onset PD with a high penetrance rate. We previously identified an asymptomatic homozygous Parkin mutation carrier who had not developed PD by her eighth decade despite the loss of functional Parkin. Here we discover a putative mechanism that protects her against PD. In contrast to Parkin-related PD patient-derived cells, the asymptomatic carrier cells show preserved mitochondrial function and mitophagy which is mediated by mitochondrial receptor Nip3-like protein X (Nix). Nix-mediated mitophagy was not affected by PINK1 knockdown. Both genetic and pharmacological induction of Nix restores mitophagy in PINK1- and Parkin-related PD patient cell lines, confirming its ability to induce mitophagy in the absence of PINK1/Parkin-mediated pathway. Moreover, Nix over-expression improves mitochondrial ATP production in these patient cells. Our results demonstrate that Nix can serve as an alternative mediator of mitophagy to maintain mitochondrial turnover, identifying Nix as a promising target for neuroprotective treatment in PINK1/Parkin-related PD.

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

PubMed Central

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

2015-01-01

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

Mitochondrial dynamics and Parkinson's disease: focus on parkin.

PubMed

Lim, Kah-Leong; Ng, Xiao-Hui; Grace, Lim Gui-Yin; Yao, Tso-Pang

2012-05-01

Parkinson's disease (PD) is a prevalent neurodegenerative disease affecting millions of individuals worldwide. Despite intensive efforts devoted to drug discovery, the disease remains incurable. To provide more effective medical therapy for PD, better understanding of the underlying causes of the disease is clearly necessary. A broad range of studies conducted over the past few decades have collectively implicated aberrant mitochondrial homeostasis as a key contributor to the development of PD. Supporting this, mutations in several PD-linked genes are directly or indirectly linked to mitochondrial dysfunction. In particular, recent discoveries have identified parkin, whose mutations are causative of recessive parkinsonism, as a key regulator of mitochondrial homeostasis. Parkin appears to be involved in the entire spectrum of mitochondrial dynamics, including organelle biogenesis, fusion/fission, and clearance via mitophagy. How a single protein can regulate such diverse mitochondrial events is as intriguing as it is amazing; the mechanism underlying this is currently under intense research. Here, we provide an overview of mitochondrial dynamics and its relationship with neurodegenerative diseases and discuss current evidence and controversies surrounding the role of parkin in mitochondrial quality control and its relevance to PD pathogenesis. Although the emerging field of parkin-mediated mitochondrial quality control has proven to be exciting, it is important to recognize that PD pathogenesis is likely to involve an intricate network of interacting pathways. Elucidating the reciprocity of pathways, particularly how other PD-related pathways potentially influence mitochondrial homeostasis, may hold the key to therapeutic development.

Endogenous Murine BST-2/Tetherin Is Not a Major Restriction Factor of Influenza A Virus Infection.

PubMed

Londrigan, Sarah L; Tate, Michelle D; Job, Emma R; Moffat, Jessica M; Wakim, Linda M; Gonelli, Christopher A; Purcell, Damien F J; Brooks, Andrew G; Villadangos, Jose A; Reading, Patrick C; Mintern, Justine D

2015-01-01

BST-2 (tetherin, CD317, HM1.24) restricts virus growth by tethering enveloped viruses to the cell surface. The role of BST-2 during influenza A virus infection (IAV) is controversial. Here, we assessed the capacity of endogenous BST-2 to restrict IAV in primary murine cells. IAV infection increased BST-2 surface expression by primary macrophages, but not alveolar epithelial cells (AEC). BST-2-deficient AEC and macrophages displayed no difference in susceptibility to IAV infection relative to wild type cells. Furthermore, BST-2 played little role in infectious IAV release from either AEC or macrophages. To examine BST-2 during IAV infection in vivo, we infected BST-2-deficient mice. No difference in weight loss or in viral loads in the lungs and/or nasal tissues were detected between BST-2-deficient and wild type animals. This study rules out a major role for endogenous BST-2 in modulating IAV in the mouse model of infection.

Endogenous Murine BST-2/Tetherin Is Not a Major Restriction Factor of Influenza A Virus Infection

PubMed Central

Job, Emma R.; Moffat, Jessica M.; Wakim, Linda M.; Gonelli, Christopher A.; Purcell, Damien F. J.; Brooks, Andrew G.; Villadangos, Jose A.; Reading, Patrick C.; Mintern, Justine D.

2015-01-01

BST-2 (tetherin, CD317, HM1.24) restricts virus growth by tethering enveloped viruses to the cell surface. The role of BST-2 during influenza A virus infection (IAV) is controversial. Here, we assessed the capacity of endogenous BST-2 to restrict IAV in primary murine cells. IAV infection increased BST-2 surface expression by primary macrophages, but not alveolar epithelial cells (AEC). BST-2-deficient AEC and macrophages displayed no difference in susceptibility to IAV infection relative to wild type cells. Furthermore, BST-2 played little role in infectious IAV release from either AEC or macrophages. To examine BST-2 during IAV infection in vivo, we infected BST-2-deficient mice. No difference in weight loss or in viral loads in the lungs and/or nasal tissues were detected between BST-2-deficient and wild type animals. This study rules out a major role for endogenous BST-2 in modulating IAV in the mouse model of infection. PMID:26566124

Covalent ISG15 conjugation positively regulates the ubiquitin E3 ligase activity of parkin

PubMed Central

Im, Eunju; Yoo, Lang; Hyun, Minju; Shin, Woo Hyun

2016-01-01

Parkinson's disease (PD) is characterized by selective loss of dopaminergic neurons in the pars compacta of the substantia nigra and accumulation of ubiquitinated proteins in aggregates called Lewy bodies. Several mutated genes have been found in familial PD patients, including SNCA (α-synuclein), PARK2 (parkin), PINK1, PARK7 (DJ-1), LRRK2 and ATP13A2. Many pathogenic mutations of PARK2, which encodes the ubiquitin E3 ligase parkin, result in loss of function, leading to accumulation of parkin substrates and consequently contributing to dopaminergic cell death. ISG15 is a member of the ubiquitin-like modifier family and is induced by stimulation with type I interferons. Similar to ubiquitin and ubiquitination, covalent conjugation of ISG15 to target proteins (ISGylation) regulates their biochemical properties. In this study, we identified parkin as a novel target of ISGylation specifically mediated by the ISG15-E3 ligase HERC5. In addition, we identified two ISGylation sites, Lys-349 and Lys-369, in the in-between-ring domain of parkin. ISGylation of these sites promotes parkin's ubiquitin E3 ligase activity by suppressing the intramolecular interaction that maintains its autoinhibited conformation and increases its cytoprotective effect. In conclusion, covalent ISG15 conjugation is a novel mode of modulating parkin activity, and alteration in this pathway may be associated with PD pathogenesis. PMID:27534820

Covalent ISG15 conjugation positively regulates the ubiquitin E3 ligase activity of parkin.

PubMed

Im, Eunju; Yoo, Lang; Hyun, Minju; Shin, Woo Hyun; Chung, Kwang Chul

2016-08-01

Parkinson's disease (PD) is characterized by selective loss of dopaminergic neurons in the pars compacta of the substantia nigra and accumulation of ubiquitinated proteins in aggregates called Lewy bodies. Several mutated genes have been found in familial PD patients, including SNCA (α-synuclein), PARK2 (parkin), PINK1, PARK7 (DJ-1), LRRK2 and ATP13A2 Many pathogenic mutations of PARK2, which encodes the ubiquitin E3 ligase parkin, result in loss of function, leading to accumulation of parkin substrates and consequently contributing to dopaminergic cell death. ISG15 is a member of the ubiquitin-like modifier family and is induced by stimulation with type I interferons. Similar to ubiquitin and ubiquitination, covalent conjugation of ISG15 to target proteins (ISGylation) regulates their biochemical properties. In this study, we identified parkin as a novel target of ISGylation specifically mediated by the ISG15-E3 ligase HERC5. In addition, we identified two ISGylation sites, Lys-349 and Lys-369, in the in-between-ring domain of parkin. ISGylation of these sites promotes parkin's ubiquitin E3 ligase activity by suppressing the intramolecular interaction that maintains its autoinhibited conformation and increases its cytoprotective effect. In conclusion, covalent ISG15 conjugation is a novel mode of modulating parkin activity, and alteration in this pathway may be associated with PD pathogenesis. © 2016 The Authors.

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

PubMed

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

2015-09-01

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

Linking F-box protein 7 and parkin to neuronal degeneration in Parkinson's disease (PD).

PubMed

Zhou, Zhi Dong; Sathiyamoorthy, Sushmitha; Angeles, Dario C; Tan, Eng King

2016-04-18

Mutations of F-box protein 7 (FBXO7) and Parkin, two proteins in ubiquitin-proteasome system (UPS), are both implicated in pathogenesis of dopamine (DA) neuron degeneration in Parkinson's disease (PD). Parkin is a HECT/RING hybrid ligase that physically receives ubiquitin on its catalytic centre and passes ubiquitin onto its substrates, whereas FBXO7 is an adaptor protein in Skp-Cullin-F-box (SCF) SCF(FBXO7) ubiquitin E3 ligase complex to recognize substrates and mediate substrates ubiquitination by SCF(FBXO7) E3 ligase. Here, we discuss the overlapping pathophysiologic mechanisms and clinical features linking Parkin and FBXO7 with autosomal recessive PD. Both proteins play an important role in neuroprotective mitophagy to clear away impaired mitochondria. Parkin can be recruited to impaired mitochondria whereas cellular stress can promote FBXO7 mitochondrial translocation. PD-linked FBXO7 can recruit Parkin into damaged mitochondria and facilitate its aggregation. WT FBXO7, but not PD-linked FBXO7 mutants can rescue DA neuron degeneration in Parkin null Drosophila. A better understanding of the common pathophysiologic mechanisms of these two proteins could unravel specific pathways for targeted therapy in PD.

Dopamine Induces Oscillatory Activities in Human Midbrain Neurons with Parkin Mutations.

PubMed

Zhong, Ping; Hu, Zhixing; Jiang, Houbo; Yan, Zhen; Feng, Jian

2017-05-02

Locomotor symptoms in Parkinson's disease (PD) are accompanied by widespread oscillatory neuronal activities in basal ganglia. Here, we show that activation of dopamine D1-class receptors elicits a large rhythmic bursting of spontaneous excitatory postsynaptic currents (sEPSCs) in midbrain neurons differentiated from induced pluripotent stem cells (iPSCs) of PD patients with parkin mutations, but not normal subjects. Overexpression of wild-type parkin, but not its PD-causing mutant, abolishes the oscillatory activities in patient neurons. Dopamine induces a delayed enhancement in the amplitude of spontaneous, but not miniature, EPSCs, thus increasing quantal content. The results suggest that presynaptic regulation of glutamatergic transmission by dopamine D1-class receptors is significantly potentiated by parkin mutations. The aberrant dopaminergic regulation of presynaptic glutamatergic transmission in patient-specific iPSC-derived midbrain neurons provides a mechanistic clue to PD pathophysiology, and it demonstrates the usefulness of this model system in understanding how mutations of parkin cause movement symptoms in Parkinson's disease. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

PARKIN overexpression in human mesenchymal stromal cells from Wharton's jelly suppresses 6-hydroxydopamine-induced apoptosis: Potential therapeutic strategy in Parkinson's disease.

PubMed

Bonilla-Porras, A R; Arevalo-Arbelaez, A; Alzate-Restrepo, J F; Velez-Pardo, C; Jimenez-Del-Rio, M

2018-01-01

Stem cell transplantation is an excellent option for regenerative or replacement therapy. However, deleterious microenvironmental and endogenous factors (e.g., oxidative stress) compromise ongoing graft survival and longevity. Therefore, (transient or stable) genetically modified cells may be reasonably thought to resist oxidative stress-induced damage. Genetic engineering of mesenchymal stromal cells (MSCs) obtained from Wharton's jelly tissue may offer some therapeutic potential. PARKIN is a multifunctional ubiquitin ligase able to protect dopaminergic cells against stress-related signaling. We, therefore, evaluated the effect of the neurotoxicant 6-hydroxydopamine (6-OHDA) on regulated cell death signaling in MSCs and investigated whether overexpression of PARKIN in MSCs was capable of modulating the effect of 6-OHDA. We transiently transfected Wharton's jelly-derived MSCs with an mCherry-PARKIN vector using the Lipofectamine LTX method. Naïve MSCs and MSCs overexpressing PARKIN were exposed to increasing concentrations of 6-OHDA. We used light and fluorescence microscopy, flow cytometry, immunocytochemistry staining, in-cell Western and Western blot analysis. After 12-24 h of 6-OHDA exposure, we detected dichlorofluorescein (DCF)-positive cells (80%) indicative of reactive oxygen species (H2O2) production, reduced cell viability (40-50%), decreased mitochondrial membrane potential (ΔΨm, ~35-45%), DNA fragmentation (18-30%), and G1-arrested cell cycle in the MSCs. 6-OHDA exposure increased the expression of the transcription factor c-JUN, increased the expression of the mitochondria maintenance Phosphatase and tensin homologue-induced putative kinase 1 (PINK1) protein and increased the expression of pro-apoptotic PUMA, caspase-3 and apoptosis-inducing factor (AIF). 6-OHDA exposure also significantly augmented the oxidation of the oxidative stress sensor, DJ-1. Overexpression of PARKIN in MSCs not only significantly reduced the expression of cell death and

Generation and characterisation of a parkin-Pacrg knockout mouse line and a Pacrg knockout mouse line.

PubMed

Stephenson, Sarah E M; Aumann, Timothy D; Taylor, Juliet M; Riseley, Jessica R; Li, Ruili; Mann, Jeffrey R; Tomas, Doris; Lockhart, Paul J

2018-05-14

Mutations in PARK2 (parkin) can result in Parkinson's disease (PD). Parkin shares a bidirectional promoter with parkin coregulated gene (PACRG) and the transcriptional start sites are separated by only ~200 bp. Bidirectionally regulated genes have been shown to function in common biological pathways. Mice lacking parkin have largely failed to recapitulate the dopaminergic neuronal loss and movement impairments seen in individuals with parkin-mediated PD. We aimed to investigate the function of PACRG and test the hypothesis that parkin and PACRG function in a common pathway by generating and characterizing two novel knockout mouse lines harbouring loss of both parkin and Pacrg or Pacrg alone. Successful modification of the targeted allele was confirmed at the genomic, transcriptional and steady state protein levels for both genes. At 18-20 months of age, there were no significant differences in the behaviour of parental and mutant lines when assessed by openfield, rotarod and balance beam. Subsequent neuropathological examination suggested there was no gross abnormality of the dopaminergic system in the substantia nigra and no significant difference in the number of dopaminergic neurons in either knockout model compared to wildtype mice.

Quantitative gait analysis in parkin disease: Possible role of dystonia.

PubMed

Castagna, Anna; Frittoli, Serena; Ferrarin, Maurizio; Del Sorbo, Francesca; Romito, Luigi M; Elia, Antonio E; Albanese, Alberto

2016-11-01

Parkin disease (PARK2, OMIM 602544) is an autosomal-recessive early-onset parkinsonism characterized by an early occurrence of lower limb dystonia. The aim of this study was to analyze spatiotemporal, kinematic, and kinetic gait parameters in patients with parkin disease in the OFF and ON conditions compared to healthy age-matched controls. Fifteen patients with parkin disease and 15 healthy age-matched controls were studied in a gait analysis laboratory with an integrated optoelectronic system. Spatiotemporal, kinematic, and kinetic gait parameters at a self-selected speed were recorded in the OFF and ON conditions. A jerk index was computed to quantify the possible reduction of smoothness of joint movements. Compared to controls, parkin patients had, either in the OFF or in the ON conditions, significant reduction of walking velocity, increased step width, and decreased percentage of double support. Kinematic analysis in both conditions showed: increased ankle dorsiflexion and knee flexion at the initial contact; maximal flexion and increased range of motion in mid stance; increased hip flexion and max extension in stance at pelvis; and increased mean tilt antiversion. Kinetics showed increased hip and knee power generation in stance in either condition. The jerk index was increased at all joints both in OFF and ON. There were no correlations between individual gait parameters and clinical ratings. Parkin patients have an abnormal gait pattern that does not vary between the OFF and the ON conditions. Variations recorded with instrumented analysis are more evident for kinematic than kinetic parameters at lower limbs. Severity of dystonia does not correlate with any individual kinematic parameter. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Parkin Knockout Inhibits Neuronal Development via Regulation of Proteasomal Degradation of p21

PubMed Central

Park, Mi Hee; Lee, Hwa-Jeong; Lee, Hye Lim; Son, Dong Ju; Ju, Jung Hoon; Hyun, Byung Kook; Jung, Sung Hee; Song, Ju-Kyoung; Lee, Dong Hun; Hwang, Chul Ju; Han, Sang Bae; Kim, Sanghyeon; Hong, Jin Tae

2017-01-01

PARK2 encodes for the E3 ubiquitin ligase parkin and is implicated in the development of Parkinson's disease (PD). Although the neuroprotective role of parkin is well known, the mechanism of PARK2's function in neural stem differentiation has not yet been thoroughly studied. Co-expressions network analysis showed that synaptosomal-associated protein 25 (SNAP-25) and brain-derived neurotrophic factor (BDNF) were positively correlated with parkin, but negatively correlated with p21 in human patient brain. We investigated a link between the ubiquitin E3 ligase parkin and proteasomal degradation of p21 for the control of neural stem cell differentiation. We found that the neurogenesis was lowered in PARK2 knockout (KO) mice compared with non-tg mice. Expression of the marker protein for neural cell differentiation such as class III beta tubulin (TUBBIII), glial fibrillary acidic protein (GFAP) and neurofilament, as well as SNAP25 and BDNF, was down regulated in PARK2 KO mice. Associated with the loss of differentiation function, p21 protein was highly accumulated in the neural stem cells of PARK2 KO mice. We discovered that p21 directly binds with parkin and is ubiquitinated by parkin which resulted in the loss of cell differentiation ability. Introduction of p21 shRNA in PARK2 KO mice significantly rescued the differentiation efficacy as well as SNAP25 and BDNF expression. c-Jun N-terminal kinase (JNK) pathway is implicated in neurogenesis and p21 degradation. We also defined the decreased p21 ubiquitination and differentiation ability were reversed after treatment with JNK inhibitor, SP600125 in PARK2 KO mice derived neural stem cells. Thus, the present study indicated that parkin knockout inhibits neural stem cell differentiation by JNK-dependent proteasomal degradation of p21. PMID:28656059

Parkin Knockout Inhibits Neuronal Development via Regulation of Proteasomal Degradation of p21.

PubMed

Park, Mi Hee; Lee, Hwa-Jeong; Lee, Hye Lim; Son, Dong Ju; Ju, Jung Hoon; Hyun, Byung Kook; Jung, Sung Hee; Song, Ju-Kyoung; Lee, Dong Hun; Hwang, Chul Ju; Han, Sang Bae; Kim, Sanghyeon; Hong, Jin Tae

2017-01-01

PARK2 encodes for the E3 ubiquitin ligase parkin and is implicated in the development of Parkinson's disease (PD). Although the neuroprotective role of parkin is well known, the mechanism of PARK2's function in neural stem differentiation has not yet been thoroughly studied. Co-expressions network analysis showed that synaptosomal-associated protein 25 (SNAP-25) and brain-derived neurotrophic factor (BDNF) were positively correlated with parkin, but negatively correlated with p21 in human patient brain. We investigated a link between the ubiquitin E3 ligase parkin and proteasomal degradation of p21 for the control of neural stem cell differentiation. We found that the neurogenesis was lowered in PARK2 knockout (KO) mice compared with non-tg mice. Expression of the marker protein for neural cell differentiation such as class III beta tubulin (TUBBIII), glial fibrillary acidic protein (GFAP) and neurofilament, as well as SNAP25 and BDNF, was down regulated in PARK2 KO mice. Associated with the loss of differentiation function, p21 protein was highly accumulated in the neural stem cells of PARK2 KO mice. We discovered that p21 directly binds with parkin and is ubiquitinated by parkin which resulted in the loss of cell differentiation ability. Introduction of p21 shRNA in PARK2 KO mice significantly rescued the differentiation efficacy as well as SNAP25 and BDNF expression. c-Jun N-terminal kinase (JNK) pathway is implicated in neurogenesis and p21 degradation. We also defined the decreased p21 ubiquitination and differentiation ability were reversed after treatment with JNK inhibitor, SP600125 in PARK2 KO mice derived neural stem cells. Thus, the present study indicated that parkin knockout inhibits neural stem cell differentiation by JNK-dependent proteasomal degradation of p21.

The relationship between Obsessive-Compulsive symptoms and PARKIN genotype: The CORE-PD study

PubMed Central

Sharp, ME; Caccappolo, E; Mejia-Santana, H; Tang, M–X; Rosado, L; Orbe Reilly, M; Ruiz, D; Louis, ED; Comella, C; Nance, M; Bressman, S; Scott, WK; Tanner, C; Waters, C; Fahn, S; Cote, L; Ford, B; Rezak, M; Novak, K; Friedman, JH; Pfeiffer, R; Payami, H; Molho, E; Factor, SA; Nutt, J; Serrano, C; Arroyo, M; Pauciulo, MW; Nichols, WC; Clark, LN; Alcalay, RN; Marder, KS

2014-01-01

Background Few studies have systematically investigated the association between PARKIN genotype and psychiatric co-morbidities of PD. PARKIN-associated PD is characterized by severe nigral dopaminergic neuronal loss, a finding that may have implications for behaviors rooted in dopaminergic circuits such as obsessive-compulsive symptoms (OCS). Methods The Schedule of Compulsions and Obsessions Patient Inventory (SCOPI) was administered to 104 patients with early-onset PD and 257 asymptomatic first-degree relatives. Carriers of one and two PARKIN mutations were compared to non-carriers. Results Among patients, carriers scored lower than non-carriers in adjusted models (one-mutation: 13.9 point difference, p=0.03; two-mutation: 24.1, p=0.001), where lower scores indicate less OCS. Among asymptomatic relatives, there was a trend towards the opposite: mutation carriers scored higher than non-carriers (one mutation p = 0.05; two mutations p = 0.13). Conclusions First, there was a significant association between PARKIN mutation status and obsessive-compulsive symptom level in both PD and asymptomatics, suggesting that OCS might represent an early non-motor dopamine-dependent feature. Second, irrespective of disease status, heterozygotes were significantly different that non-carriers suggesting that PARKIN heterozygosity may contribute to phenotype. PMID:25393808

Parkin Binds to α/β Tubulin and Increases their Ubiquitination and Degradation

PubMed Central

Ren, Yong; Zhao, Jinghui; Feng, Jian

2007-01-01

In addition to inhibiting the mitochondrial respiratory chain, toxins known to cause Parkinson’s disease (PD), such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone, also strongly depolymerize microtubules and increase tubulin degradation. Microtubules are polymers of tubulin α/β heterodimers, whose correct folding requires coordinated actions of cellular chaperonins and co-factors. Misfolded tubulin monomers are highly toxic and quickly degraded through a hitherto unknown mechanism. Here we report that parkin, a protein-ubiquitin E3 ligase linked to PD, was tightly bound to microtubules in taxol-mediated microtubule co-assembly assays. In lysates from the rat brain or transfected HEK293 cells, α-tubulin and β-tubulin were strongly co-immunoprecipitated with parkin at 4°C in the presence of colchicine, a condition where tubulin exits as α/β heterodimers. At the subcellular level, parkin exhibited punctate immunostaining along microtubules in rat brain sections, cultured primary neurons, glial cells and cell lines. This pattern of subcellular localization was abolished in cells treated with the microtubule-depolymerizing drug colchicine. The binding between parkin and tubulin apparently led to increased ubiquitination and accelerated degradation of α- and β-tubulins in HEK293 cells. Similarly ubiquitinated tubulins were also observed in rat brain lysates. Furthermore, parkin mutants found in PD patients did not ubiquitinate or degrade either tubulin. Taken together, our results show that parkin is a novel tubulin-binding protein, as well as a microtubule-associated protein (MAP). Its ability to enhance the ubiquitination and degradation of misfolded tubulins may play a significant role in protecting neurons from toxins that cause PD. PMID:12716939

Nucleotide sequence analysis establishes the role of endogenous murine leukemia virus DNA segments in formation of recombinant mink cell focus-forming murine leukemia viruses.

PubMed Central

Khan, A S

1984-01-01

The sequence of 363 nucleotides near the 3' end of the pol gene and 564 nucleotides from the 5' terminus of the env gene in an endogenous murine leukemia viral (MuLV) DNA segment, cloned from AKR/J mouse DNA and designated as A-12, was obtained. For comparison, the nucleotide sequence in an analogous portion of AKR mink cell focus-forming (MCF) 247 MuLV provirus was also determined. Sequence features unique to MCF247 MuLV DNA in the 3' pol and 5' env regions were identified by comparison with nucleotide sequences in analogous regions of NFS -Th-1 xenotropic and AKR ecotropic MuLV proviruses. These included (i) an insertion of 12 base pairs encoding four amino acids located 60 base pairs from the 3' terminus of the pol gene and immediately preceding the env gene, (ii) the deletion of 12 base pairs (encoding four amino acids) and the insertion of 3 base pairs (encoding one amino acid) in the 5' portion of the env gene, and (iii) single base substitutions resulting in 2 MCF247 -specific amino acids in the 3' pol and 23 in the 5' env regions. Nucleotide sequence comparison involving the 3' pol and 5' env regions of AKR MCF247 , NFS xenotropic, and AKR ecotropic MuLV proviruses with the cloned endogenous MuLV DNA indicated that MCF247 proviral DNA sequences were conserved in the cloned endogenous MuLV proviral segment. In fact, total nucleotide sequence identity existed between the endogenous MuLV DNA and the MCF247 MuLV provirus in the 3' portion of the pol gene. In the 5' env region, only 4 of 564 nucleotides were different, resulting in three amino acid changes between AKR MCF247 MuLV DNA and the endogenous MuLV DNA present in clone A-12. In addition, nucleotide sequence comparison indicated that Moloney-and Friend-MCF MuLVs were also highly related in the 3' pol and 5' env regions to the cloned endogenous MuLV DNA. These results establish the role of endogenous MuLV DNA segments in generation of recombinant MCF viruses. PMID:6328017

Parkin binds the Rpn10 subunit of 26S proteasomes through its ubiquitin-like domain

PubMed Central

Sakata, Eri; Yamaguchi, Yoshiki; Kurimoto, Eiji; Kikuchi, Jun; Yokoyama, Shigeyuki; Yamada, Shingo; Kawahara, Hiroyuki; Yokosawa, Hideyoshi; Hattori, Nobutaka; Mizuno, Yoshikuni; Tanaka, Keiji; Kato, Koichi

2003-01-01

Parkin, a product of the causative gene of autosomal-recessive juvenile parkinsonism (AR-JP), is a RING-type E3 ubiquitin ligase and has an amino-terminal ubiquitin-like (Ubl) domain. Although a single mutation that causes an Arg to Pro substitution at position 42 of the Ubl domain (the Arg 42 mutation) has been identified in AR-JP patients, the function of this domain is not clear. In this study, we determined the three-dimensional structure of the Ubl domain of parkin by NMR, in particular by extensive use of backbone 15N-1H residual dipolar-coupling data. Inspection of chemical-shift-perturbation data showed that the parkin Ubl domain binds the Rpn10 subunit of 26S proteasomes via the region of parkin that includes position 42. Our findings suggest that the Arg 42 mutation induces a conformational change in the Rpn10-binding site of Ubl, resulting in impaired proteasomal binding of parkin, which could be the cause of AR-JP. PMID:12634850

Impact of altered phosphorylation on loss of function of juvenile Parkinsonism-associated genetic variants of the E3 ligase parkin.

PubMed

Aguirre, Jacob D; Dunkerley, Karen M; Lam, Rica; Rusal, Michele; Shaw, Gary S

2018-04-27

Autosomal recessive juvenile Parkinsonism (ARJP) is an inherited neurodegenerative disease in which 50% of affected individuals harbor mutations in the gene encoding the E3 ligase parkin. Parkin regulates the mitochondrial recycling pathway, which is induced by oxidative stress. In its native state, parkin is auto-inhibited by its N-terminal ubiquitin-like (Ubl) domain, which blocks the binding site for an incoming E2∼ubiquitin conjugate, needed for parkin's ubiquitination activity. Parkin is activated via phosphorylation of Ser-65 in its Ubl domain by PTEN-induced putative kinase 1 (PINK1) and a ubiquitin molecule phosphorylated at a position equivalent to Ser-65 in parkin. Here we have examined the underlying molecular mechanism of phosphorylation of parkin's Ubl domain carrying ARJP-associated substitutions and how altered phosphorylation modulates parkin activation and ubiquitination. We found that three substitutions in the Ubl domain (G12R, R33Q, and R42P) significantly decrease PINK1's ability to phosphorylate the Ubl domain. We noted that two basic loss-of-function substitutions (R33Q and R42P) are close to acidic patches in the proposed PINK1-parkin interface, indicating that ionic interactions at this site may be important for efficient parkin phosphorylation. Increased auto-ubiquitination with unique ubiquitin chain patterns was observed for two other Ubl domain substitutions (G12R and T55I), suggesting that these substitutions, along with phosphorylation, increase parkin degradation. Moreover, Ubl domain phosphorylation decreased its affinity for the potential effector protein ataxin-3, which edits ubiquitin chain building by parkin. Overall, our work provides a framework for the mechanisms of parkin's loss-of-function, indicating an interplay between ARJP-associated substitutions and phosphorylation of its Ubl domain. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

De novo tetrahydrobiopterin biosynthesis is impaired in the inflammed striatum of parkin(-/-) mice.

PubMed

de Paula Martins, Roberta; Glaser, Viviane; Aguiar, Aderbal S; de Paula Ferreira, Priscila Maximiliano; Ghisoni, Karina; da Luz Scheffer, Débora; Lanfumey, Laurence; Raisman-Vozari, Rita; Corti, Olga; De Paul, Ana Lucia; da Silva, Rodrigo Augusto; Latini, Alexandra

2018-06-01

Parkinson's disease (PD), the second-most prevalent neurodegenerative disease, is primarily characterized by neurodegeneration in the substantia nigra pars compacta, resulting in motor impairment. Loss-of-function mutations in parkin are the major cause of the early onset familial form of the disease. Although rodents deficient in parkin (parkin (-/-) ) have some dopaminergic system dysfunction associated with central oxidative stress and energy metabolism deficiencies, these animals only display nigrostriatal pathway degeneration under inflammatory conditions. This study investigated the impact of the inflammatory stimulus induced by lypopolisaccharide (LPS) on tetrahydrobiopterin (BH4) synthesizing enzymes (de novo and salvage pathways), since this cofactor is essential for dopamine synthesis. The mitochondrial content and architecture was investigated in the striatum of LPS-exposed parkin (-/-) mice. As expected, the LPS (0.33 mg/kg; i.p.) challenge compromised spontaneous locomotion and social interaction with juvenile parkin (-/-) and WT mice. Moreover, the genotype impacted the kinetics of the investigation of the juvenile. The inflammatory scenario did not induce apparent changes in mitochondrial ultrastructure; however, it increased the quantity of mitochondria, which were of smaller size, and provoked the perinuclear distribution of the organelle. Furthermore, the BH4 de novo biosynthetic pathway failed to be up-regulated in the LPS challenge, a well-known stimulus for its activation. The LPS treatment increased sepiapterin reductase (SPR) expression, suggesting compensation by the salvage pathway. This might indicate that dopamine synthesis is compromised in parkin (-/-) mice under inflammatory conditions. Finally, this scenario impaired the striatal expression of the transcription factor BDNF, possibly favoring cell death. © 2018 International Federation for Cell Biology.

Restriction by APOBEC3 proteins of endogenous retroviruses with an extracellular life cycle: ex vivo effects and in vivo "traces" on the murine IAPE and human HERV-K elements

PubMed Central

Esnault, Cécile; Priet, Stéphane; Ribet, David; Heidmann, Odile; Heidmann, Thierry

2008-01-01

Background APOBEC3 cytosine deaminases have been demonstrated to restrict infectivity of a series of retroviruses, with different efficiencies depending on the retrovirus. In addition, APOBEC3 proteins can severely restrict the intracellular transposition of a series of retroelements with a strictly intracellular life cycle, including the murine IAP and MusD LTR-retrotransposons. Results Here we show that the IAPE element, which is the infectious progenitor of the strictly intracellular IAP elements, and the infectious human endogenous retrovirus HERV-K are restricted by both murine and human APOBEC3 proteins in an ex vivo assay for infectivity, with evidence in most cases of strand-specific G-to-A editing of the proviruses, with the expected signatures. In silico analysis of the naturally occurring genomic copies of the corresponding endogenous elements performed on the mouse and human genomes discloses "traces" of APOBEC3-editing, with the specific signature of the murine APOBEC3 and human APOBEC3G enzymes, respectively, and to a variable extent depending on the family member. Conclusion These results indicate that the IAPE and HERV-K elements, which can only replicate via an extracellular infection cycle, have been restricted at the time of their entry, amplification and integration into their target host genomes by definite APOBEC3 proteins, most probably acting in evolution to limit the mutagenic effect of these endogenized extracellular parasites. PMID:18702815

Restless legs syndrome, rapid eye movement sleep behavior disorder, and hypersomnia in patients with two parkin mutations.

PubMed

Limousin, Nadège; Konofal, Eric; Karroum, Elias; Lohmann, Ebba; Theodorou, Ioannis; Dürr, Alexandra; Arnulf, Isabelle

2009-10-15

Parkin gene mutations cause a juvenile parkinsonism. Patients with these mutations may commonly exhibit REM sleep behaviour disorders, but other sleep problems (insomnia, sleepiness, restless legs syndrome) have not been studied. The aim of this study was to evaluate the sleep-wake phenotype in patients with two parkin mutations, compared with patients with idiopathic Parkinson's disease (iPD). Sleep interview and overnight video-polysomnography, followed by multiple sleep latency tests, were assessed in 11 consecutive patients with two parkin mutations (aged 35-60 years, from seven families) and 11 sex-matched patients with iPD (aged 51-65 years). Sleep complaints in the parkin group included insomnia (73% patients versus 45% in the iPD group), restless legs syndrome (45%, versus none in the iPD group, P = 0.04), and daytime sleepiness (45%, versus 54% in the iPD group). Of the parkin patients, 45% had REM sleep without atonia, but only 9% had a definite REM sleep behavior disorder. All sleep measures were similar in the parkin and iPD groups. Two parkin siblings had a central hypersomnia, characterized by mean daytime sleep latencies of 3 min, no sleep onset REM periods, and normal nighttime sleep. Although the patients with two parkin mutations were young, their sleep phenotype paralleled the clinical and polygraphic sleep recording abnormalities reported in iPD, except that restless legs syndrome was more prevalent and secondary narcolepsy was absent.

Parkin clearance of dysfunctional mitochondria regulates ROS levels and increases survival of human chondrocytes.

PubMed

Ansari, M Y; Khan, N M; Ahmad, I; Haqqi, T M

2017-08-08

Mitochondrial dysfunction, oxidative stress and chondrocyte death are important contributors to the development and pathogenesis of osteoarthritis (OA). In this study, we determined the expression and role of Parkin in the clearance of damaged/dysfunctional mitochondria, regulation of reactive oxygen species (ROS) levels and chondrocyte survival under pathological conditions. Human chondrocytes were from the unaffected area of knee OA cartilage (n = 12) and were stimulated with IL-1β to mimic pathological conditions. Mitochondrial membrane depolarization and ROS levels were determined using specific dyes and flow cytometry. Autophagy was determined by Western blotting for ATG5, Beclin1, immunofluorescence staining and confocal microscopy. Gene expression was determined by RT-qPCR. siRNA, wild-type and mutant Parkin plasmids were transfected using Amaxa system. Apoptosis was determined by PI staining of chondrocytes and TUNEL assay. IL-1β-stimulated OA chondrocytes showed high levels of ROS generation, mitochondrial membrane damage, accumulation of damaged mitochondria and higher incidence of apoptosis. IL-1β stimulation of chondrocytes with depleted Parkin expression resulted in sustained high levels of ROS, accumulation of damaged/dysfunctional mitochondria and enhanced apoptosis. Parkin translocation to depolarized/damaged mitochondria and recruitment of p62/SQSTM1 was required for the elimination of damaged/dysfunctional mitochondria in IL-1β-stimulated OA chondrocytes. Importantly we demonstrate that Parkin elimination of depolarized/damaged mitochondria required the Parkin ubiquitin ligase activity and resulted in reduced ROS levels and inhibition of apoptosis in OA chondrocytes under pathological conditions. Our data demonstrates that Parkin functions to eliminate depolarized/damaged mitochondria in chondrocytes which is necessary for mitochondrial quality control, regulation of ROS levels and chondrocyte survival under pathological conditions

Hepatitis B Virus X protein elevates Parkin-mediated mitophagy through Lon Peptidase in starvation.

PubMed

Huang, Xiao-Yun; Li, Dan; Chen, Zhi-Xin; Huang, Yue-Hong; Gao, Wen-Yu; Zheng, Bi-Yun; Wang, Xiao-Zhong

2018-07-01

Hepatocellular Carcinoma (HCC) is the fifth most prevalent cancer worldwide. Specially, Hepatitis B viurs X protein (HBx) is a leading factor in the progression of Hepatitis B viurs-related HCC. Nutrient-deprived tumor microenvironment also contributes to tumor development. However, the role of HBx in nutrient-deprived HCC has received little investigation. Here, we show that HBx elevates PINK1-Parkin mediating mitophagy in starvation. HBx not only increases the PINK1/Parkin gene expression but also accelerates Parkin recruitment to partial mitochondria. Further analysis indicates that, HBx either promotes mitochondrial unfolded protein response, with remarkable mitochondrial LONP1 increases, or reduces LONP1 expression in cytosol inducing LONP1-Parkin pathway, both consequently enhancing mitophagy. Moreover, the enhanced mitophagy lowers mitochondrial apoptosis in starved hepatoma cells, and Bax is implied in the machinery. In addition, we define differential centrifuge, 3000 g or 12,000 g to pellet mitochondria, as an effective method to obtain distinct mitochondria. In collect, HBx regulates diverse aspects of LONP1 and Parkin, enhancing mitophagy in starvation. This study may shed new insights into the machinery development of hepatocellular carcinoma. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Murine endogenous retroviruses

PubMed Central

2016-01-01

Up to 10% of the mouse genome is comprised of endogenous retrovirus (ERV) sequences, and most represent the remains of ancient germ line infections. Our knowledge of the three distinct classes of ERVs is inversely correlated with their copy number, and their characterization has benefited from the availability of divergent wild mouse species and subspecies, and from ongoing analysis of the Mus genome sequence. In contrast to human ERVs, which are nearly all extinct, active mouse ERVs can still be found in all three ERV classes. The distribution and diversity of ERVs has been shaped by host-virus interactions over the course of evolution, but ERVs have also been pivotal in shaping the mouse genome by altering host genes through insertional mutagenesis, by adding novel regulatory and coding sequences, and by their co-option by host cells as retroviral resistance genes. We review mechanisms by which an adaptive coexistence has evolved. (Part of a Multi-author Review) PMID:18818872

Metformin Restores Parkin-Mediated Mitophagy, Suppressed by Cytosolic p53

PubMed Central

Song, Young Mi; Lee, Woo Kyung; Lee, Yong-ho; Kang, Eun Seok; Cha, Bong-Soo; Lee, Byung-Wan

2016-01-01

Metformin is known to alleviate hepatosteatosis by inducing 5’ adenosine monophosphate (AMP)-kinase-independent, sirtuin 1 (SIRT1)-mediated autophagy. Dysfunctional mitophagy in response to glucolipotoxicities might play an important role in hepatosteatosis. Here, we investigated the mechanism by which metformin induces mitophagy through restoration of the suppressed Parkin-mediated mitophagy. To this end, our ob/ob mice were divided into three groups: (1) ad libitum feeding of a standard chow diet; (2) intraperitoneal injections of metformin 300 mg/kg; and (3) 3 g/day caloric restriction (CR). HepG2 cells were treated with palmitate (PA) plus high glucose in the absence or presence of metformin. We detected enhanced mitophagy in ob/ob mice treated with metformin or CR, whereas mitochondrial spheroids were observed in mice fed ad libitum. Metabolically stressed ob/ob mice and PA-treated HepG2 cells showed an increase in expression of endoplasmic reticulum (ER) stress markers and cytosolic p53. Cytosolic p53 inhibited mitophagy by disturbing the mitochondrial translocation of Parkin, as demonstrated by immunoprecipitation. However, metformin decreased ER stress and p53 expression, resulting in induction of Parkin-mediated mitophagy. Furthermore, pifithrin-α, a specific inhibitor of p53, increased mitochondrial incorporation into autophagosomes. Taken together, these results indicate that metformin treatment facilitates Parkin-mediated mitophagy rather than mitochondrial spheroid formation by decreasing the inhibitory interaction with cytosolic p53 and increasing degradation of mitofusins. PMID:26784190

Parkin and PINK1 function in a vesicular trafficking pathway regulating mitochondrial quality control

PubMed Central

McLelland, Gian-Luca; Soubannier, Vincent; Chen, Carol X; McBride, Heidi M; Fon, Edward A

2014-01-01

Mitochondrial dysfunction has long been associated with Parkinson's disease (PD). Parkin and PINK1, two genes associated with familial PD, have been implicated in the degradation of depolarized mitochondria via autophagy (mitophagy). Here, we describe the involvement of parkin and PINK1 in a vesicular pathway regulating mitochondrial quality control. This pathway is distinct from canonical mitophagy and is triggered by the generation of oxidative stress from within mitochondria. Wild-type but not PD-linked mutant parkin supports the biogenesis of a population of mitochondria-derived vesicles (MDVs), which bud off mitochondria and contain a specific repertoire of cargo proteins. These MDVs require PINK1 expression and ultimately target to lysosomes for degradation. We hypothesize that loss of this parkin- and PINK1-dependent trafficking mechanism impairs the ability of mitochondria to selectively degrade oxidized and damaged proteins leading, over time, to the mitochondrial dysfunction noted in PD. PMID:24446486

Parkin promotes proteasomal degradation of p62: implication of selective vulnerability of neuronal cells in the pathogenesis of Parkinson's disease.

PubMed

Song, Pingping; Li, Shanshan; Wu, Hao; Gao, Ruize; Rao, Guanhua; Wang, Dongmei; Chen, Ziheng; Ma, Biao; Wang, Hongxia; Sui, Nan; Deng, Haiteng; Zhang, Zhuohua; Tang, Tieshan; Tan, Zheng; Han, Zehan; Lu, Tieyuan; Zhu, Yushan; Chen, Quan

2016-02-01

Mutations or inactivation of parkin, an E3 ubiquitin ligase, are associated with familial form or sporadic Parkinson's disease (PD), respectively, which manifested with the selective vulnerability of neuronal cells in substantia nigra (SN) and striatum (STR) regions. However, the underlying molecular mechanism linking parkin with the etiology of PD remains elusive. Here we report that p62, a critical regulator for protein quality control, inclusion body formation, selective autophagy and diverse signaling pathways, is a new substrate of parkin. P62 levels were increased in the SN and STR regions, but not in other brain regions in parkin knockout mice. Parkin directly interacts with and ubiquitinates p62 at the K13 to promote proteasomal degradation of p62 even in the absence of ATG5. Pathogenic mutations, knockdown of parkin or mutation of p62 at K13 prevented the degradation of p62. We further showed that parkin deficiency mice have pronounced loss of tyrosine hydroxylase positive neurons and have worse performance in motor test when treated with 6-hydroxydopamine hydrochloride in aged mice. These results suggest that, in addition to their critical role in regulating autophagy, p62 are subjected to parkin mediated proteasomal degradation and implicate that the dysregulation of parkin/p62 axis may involve in the selective vulnerability of neuronal cells during the onset of PD pathogenesis.

S-Nitrosylation of parkin as a novel regulator of p53-mediated neuronal cell death in sporadic Parkinson’s disease

PubMed Central

2013-01-01

Background Mutations in the gene encoding parkin, a neuroprotective protein with dual functions as an E3 ubiquitin ligase and transcriptional repressor of p53, are linked to familial forms of Parkinson’s disease (PD). We hypothesized that oxidative posttranslational modification of parkin by environmental toxins may contribute to sporadic PD. Results We first demonstrated that S-nitrosylation of parkin decreased its activity as a repressor of p53 gene expression, leading to upregulation of p53. Chromatin immunoprecipitation as well as gel-shift assays showed that parkin bound to the p53 promoter, and this binding was inhibited by S-nitrosylation of parkin. Additionally, nitrosative stress induced apoptosis in cells expressing parkin, and this death was, at least in part, dependent upon p53. In primary mesencephalic cultures, pesticide-induced apoptosis was prevented by inhibition of nitric oxide synthase (NOS). In a mouse model of pesticide-induced PD, both S-nitrosylated (SNO-)parkin and p53 protein levels were increased, while administration of a NOS inhibitor mitigated neuronal death in these mice. Moreover, the levels of SNO-parkin and p53 were simultaneously elevated in postmortem human PD brain compared to controls. Conclusions Taken together, our data indicate that S-nitrosylation of parkin, leading to p53-mediated neuronal cell death, contributes to the pathophysiology of sporadic PD. PMID:23985028

Myocardial 123I-metaiodobenzylguanidine scintigraphy in patients with homozygous and heterozygous parkin mutations.

PubMed

De Rosa, Anna; Pellegrino, Teresa; Pappatà, Sabina; Pellecchia, Maria Teresa; Peluso, Silvio; Saccà, Francesco; Barone, Paolo; Cuocolo, Alberto; De Michele, Giuseppe

2017-02-01

PARK2 is an autosomal recessive parkinsonism caused by parkin gene mutations. Several Parkinson's Disease (PD) cases harbor single parkin mutations, raising a debate about the pathogenic meaning of heterozygous mutations. Here, we evaluate cardiac autonomic innervation in patients with either two or one parkin mutations compared to patients with idiopathic PD (IPD). Myocardial 123 I-metaiodobenzylguanidine (MIBG) scintigraphy was performed in six PD patients with single parkin mutations (HET), four with two mutations (PARK2), and eight with IPD. In comparison to control group, IPD patients showed lower early and late heart-to-mediastinum (H/M) ratios and higher washout rates, whereas HET patients had only lower early H/M ratio, and PARK2 patients were not different for any parameter. At individual level, MIBG findings were abnormal in 7/8 IPD, in 4/6 HET and in 1/4 PARK2 patients. Preserved cardiac 123 I-MIBG uptake confirms that PARK2 pathogenic mechanism, at least partially, differs from that responsible for IPD. HET subjects show intermediate findings, suggesting possible heterogeneity.

Interaction between RING1 (R1) and the Ubiquitin-like (UBL) Domains Is Critical for the Regulation of Parkin Activity*

PubMed Central

Ham, Su Jin; Lee, Soo Young; Song, Saera; Chung, Ju-Ryung; Choi, Sekyu; Chung, Jongkyeong

2016-01-01

Parkin is an E3 ligase that contains a ubiquitin-like (UBL) domain in the N terminus and an R1-in-between-ring-RING2 motif in the C terminus. We showed that the UBL domain specifically interacts with the R1 domain and negatively regulates Parkin E3 ligase activity, Parkin-dependent mitophagy, and Parkin translocation to the mitochondria. The binding between the UBL domain and the R1 domain was suppressed by carbonyl cyanide m-chlorophenyl hydrazone treatment or by expression of PTEN-induced putative kinase 1 (PINK1), an upstream kinase that phosphorylates Parkin at the Ser-65 residue of the UBL domain. Moreover, we demonstrated that phosphorylation of the UBL domain at Ser-65 prevents its binding to the R1 domain and promotes Parkin activities. We further showed that mitochondrial translocation of Parkin, which depends on phosphorylation at Ser-65, and interaction between the R1 domain and a mitochondrial outer membrane protein, VDAC1, are suppressed by binding of the UBL domain to the R1 domain. Interestingly, Parkin with missense mutations associated with Parkinson disease (PD) in the UBL domain, such as K27N, R33Q, and A46P, did not translocate to the mitochondria and induce E3 ligase activity by m-chlorophenyl hydrazone treatment, which correlated with the interaction between the R1 domain and the UBL domain with those PD mutations. These findings provide a molecular mechanism of how Parkin recruitment to the mitochondria and Parkin activation as an E3 ubiquitin ligase are regulated by PINK1 and explain the previously unknown mechanism of how Parkin mutations in the UBL domain cause PD pathogenesis. PMID:26631732

Interaction between RING1 (R1) and the Ubiquitin-like (UBL) Domains Is Critical for the Regulation of Parkin Activity.

PubMed

Ham, Su Jin; Lee, Soo Young; Song, Saera; Chung, Ju-Ryung; Choi, Sekyu; Chung, Jongkyeong

2016-01-22

Parkin is an E3 ligase that contains a ubiquitin-like (UBL) domain in the N terminus and an R1-in-between-ring-RING2 motif in the C terminus. We showed that the UBL domain specifically interacts with the R1 domain and negatively regulates Parkin E3 ligase activity, Parkin-dependent mitophagy, and Parkin translocation to the mitochondria. The binding between the UBL domain and the R1 domain was suppressed by carbonyl cyanide m-chlorophenyl hydrazone treatment or by expression of PTEN-induced putative kinase 1 (PINK1), an upstream kinase that phosphorylates Parkin at the Ser-65 residue of the UBL domain. Moreover, we demonstrated that phosphorylation of the UBL domain at Ser-65 prevents its binding to the R1 domain and promotes Parkin activities. We further showed that mitochondrial translocation of Parkin, which depends on phosphorylation at Ser-65, and interaction between the R1 domain and a mitochondrial outer membrane protein, VDAC1, are suppressed by binding of the UBL domain to the R1 domain. Interestingly, Parkin with missense mutations associated with Parkinson disease (PD) in the UBL domain, such as K27N, R33Q, and A46P, did not translocate to the mitochondria and induce E3 ligase activity by m-chlorophenyl hydrazone treatment, which correlated with the interaction between the R1 domain and the UBL domain with those PD mutations. These findings provide a molecular mechanism of how Parkin recruitment to the mitochondria and Parkin activation as an E3 ubiquitin ligase are regulated by PINK1 and explain the previously unknown mechanism of how Parkin mutations in the UBL domain cause PD pathogenesis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Involvement of PINK1/parkin-mediated mitophagy in ZnO nanoparticle-induced toxicity in BV-2 cells.

PubMed

Wei, Limin; Wang, Jianfeng; Chen, Aijie; Liu, Jia; Feng, Xiaoli; Shao, Longquan

2017-01-01

With the increasing application of zinc oxide nanoparticles (ZnO NPs) in biological materials, the neurotoxicity caused by these particles has raised serious concerns. However, the underlying molecular mechanisms of the toxic effect of ZnO NPs on brain cells remain unclear. Mitochondrial damage has been reported to be a factor in the toxicity of ZnO NPs. PINK1/parkin-mediated mitophagy is a newly emerging additional function of autophagy that selectively degrades impaired mitochondria. Here, a PINK1 gene knockdown BV-2 cell model was established to determine whether PINK1/parkin-mediated mitophagy was involved in ZnO NP-induced toxicity in BV-2 cells. The expression of total parkin, mito-parkin, cyto-parkin, and PINK1 both in wild type and PINK1 -/- BV-2 cells was evaluated using Western blot analysis after the cells were exposed to 10 μg/mL of 50 nm ZnO NPs for 2, 4, 8, 12, and 24 h. The findings suggested that the downregulation of PINK1 resulted in a significant reduction in the survival rate after ZnO NP exposure compared with that of control cells. ZnO NPs were found to induce the transportation of parkin from the cytoplasm to the mitochondria, implying the involvement of mitophagy in ZnO NP-induced toxicity. The deletion of the PINK1 gene inhibited the recruitment of parkin to the mitochondria, causing failure of the cell to trigger mitophagy. The present study demonstrated that apart from autophagy, PINK1/parkin-mediated mitophagy plays a protective role in ZnO NP-induced cytotoxicity.

Involvement of PINK1/parkin-mediated mitophagy in ZnO nanoparticle-induced toxicity in BV-2 cells

PubMed Central

Wei, Limin; Wang, Jianfeng; Chen, Aijie; Liu, Jia; Feng, Xiaoli; Shao, Longquan

2017-01-01

With the increasing application of zinc oxide nanoparticles (ZnO NPs) in biological materials, the neurotoxicity caused by these particles has raised serious concerns. However, the underlying molecular mechanisms of the toxic effect of ZnO NPs on brain cells remain unclear. Mitochondrial damage has been reported to be a factor in the toxicity of ZnO NPs. PINK1/parkin-mediated mitophagy is a newly emerging additional function of autophagy that selectively degrades impaired mitochondria. Here, a PINK1 gene knockdown BV-2 cell model was established to determine whether PINK1/parkin-mediated mitophagy was involved in ZnO NP-induced toxicity in BV-2 cells. The expression of total parkin, mito-parkin, cyto-parkin, and PINK1 both in wild type and PINK1−/− BV-2 cells was evaluated using Western blot analysis after the cells were exposed to 10 μg/mL of 50 nm ZnO NPs for 2, 4, 8, 12, and 24 h. The findings suggested that the downregulation of PINK1 resulted in a significant reduction in the survival rate after ZnO NP exposure compared with that of control cells. ZnO NPs were found to induce the transportation of parkin from the cytoplasm to the mitochondria, implying the involvement of mitophagy in ZnO NP-induced toxicity. The deletion of the PINK1 gene inhibited the recruitment of parkin to the mitochondria, causing failure of the cell to trigger mitophagy. The present study demonstrated that apart from autophagy, PINK1/parkin-mediated mitophagy plays a protective role in ZnO NP-induced cytotoxicity. PMID:28331313

Overexpression of Buffy enhances the loss of parkin and suppresses the loss of Pink1 phenotypes in Drosophila.

PubMed

M'Angale, P Githure; Staveley, Brian E

2017-03-01

Mutations in parkin (PARK2) and Pink1 (PARK6) are responsible for autosomal recessive forms of early onset Parkinson's disease (PD). Attributed to the failure of neurons to clear dysfunctional mitochondria, loss of gene expression leads to loss of nigrostriatal neurons. The Pink1/parkin pathway plays a role in the quality control mechanism aimed at eliminating defective mitochondria, and the failure of this mechanism results in a reduced lifespan and impaired locomotor ability, among other phenotypes. Inhibition of parkin or Pink1 through the induction of stable RNAi transgene in the Ddc-Gal4-expressing neurons results in such phenotypes to model PD. To further evaluate the effects of the overexpression of the Bcl-2 homologue Buffy, we analysed lifespan and climbing ability in both parkin-RNAi- and Pink1-RNAi-expressing flies. In addition, the effect of Buffy overexpression upon parkin-induced developmental eye defects was examined through GMR-Gal4-dependent expression. Curiously, Buffy overexpression produced very different effects: the parkin-induced phenotypes were enhanced, whereas the Pink1-enhanced phenotypes were suppressed. Interestingly, the overexpression of Buffy along with the inhibition of parkin in the neuron-rich eye results in the suppression of the developmental eye defects.

Lack of Parkin Anticipates the Phenotype and Affects Mitochondrial Morphology and mtDNA Levels in a Mouse Model of Parkinson's Disease.

PubMed

Pinto, Milena; Nissanka, Nadee; Moraes, Carlos T

2018-01-24

PARK2 is the most common gene mutated in monogenic recessive familial cases of Parkinson's disease (PD). Pathogenic mutations cause a loss of function of the encoded protein Parkin. ParkinKO mice, however, poorly represent human PD symptoms as they only exhibit mild motor phenotypes, minor dopamine metabolism abnormalities, and no signs of dopaminergic neurodegeneration. Parkin has been shown to participate in mitochondrial turnover, by targeting damaged mitochondria with low membrane potential to mitophagy. We studied the role of Parkin on mitochondrial quality control in vivo by knocking out Parkin in the PD-mito- Pst I mouse (males), where the mitochondrial DNA (mtDNA) undergoes double-strand breaks only in dopaminergic neurons. The lack of Parkin promoted earlier onset of dopaminergic neurodegeneration and motor defects in the PD-mito- Pst I mice, but it did not worsen the pathology. The lack of Parkin affected mitochondrial morphology in dopaminergic axons and was associated with an increase in mtDNA levels (mutant and wild type). Unexpectedly, it did not cause a parallel increase in mitochondrial mass or mitophagy. Our results suggest that Parkin affects mtDNA levels in a mitophagy-independent manner. SIGNIFICANCE STATEMENT Parkinson's disease is characterized by progressive motor symptoms due to the selective loss of dopaminergic neurons in the substantia nigra. Loss-of-function mutations of Parkin cause some monogenic forms of Parkinson's disease, possibly through its role in mitochondrial turnover and quality control. To study whether Parkin has a role in vivo in the context of mitochondrial damage, we knocked out Parkin in a mouse model in which the mitochondrial DNA is damaged in dopaminergic neurons. We found that the loss of Parkin did not exacerbate the parkinsonian pathology already present in the mice, but it was associated with an increase in mtDNA levels (mutant and wild-type) without altering mitochondrial mass. These results shed new light on

Parkin Protects Against Misfolded SOD1 Toxicity by Promoting Its Aggresome Formation and Autophagic Clearance.

PubMed

Yung, Cheryl; Sha, Di; Li, Lian; Chin, Lih-Shen

2016-11-01

Mutations in Cu/Zn superoxide dismutase (SOD1) cause autosomal dominant amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease with no effective treatment. Despite ample evidence indicating involvement of mutation-induced SOD1 protein misfolding and aggregation in ALS pathogenesis, the molecular mechanisms that control cellular management of misfolded, aggregation-prone SOD1 mutant proteins remain unclear. Here, we report that parkin, an E3 ubiquitin-protein ligase which is linked to Parkinson's disease, is a novel regulator of cellular defense against toxicity induced by ALS-associated SOD1 mutant proteins. We find that parkin mediates K63-linked polyubiquitination of SOD1 mutants in cooperation with the UbcH13/Uev1a E2 enzyme and promotes degradation of these misfolded SOD1 proteins by the autophagy-lysosome system. In response to strong proteotoxic stress associated with proteasome impairment, parkin promotes sequestration of misfolded and aggregated SOD1 proteins to form perinuclear aggresomes, regulates positioning of lysosomes around misfolded SOD1 aggresomes, and facilitates aggresome clearance by autophagy. Our findings reveal parkin-mediated cytoprotective mechanisms against misfolded SOD1 toxicity and suggest that enhancing parkin-mediated cytoprotection may provide a novel therapeutic strategy for treating ALS.

ENDOGENOUS RETROVIRUSES MOBILIZED DURING FRIEND MURINE LEUKEMIA VIRUS INFECTION

PubMed Central

Hansen, Ethan; Hendrick, Duncan; Malik, Frank; Evans, Leonard H.

2016-01-01

We have demonstrated in a mouse model that infection with a retrovirus can lead not only to the generation of recombinants between exogenous and endogenous gammaretrovirus, but also to the mobilization of endogenous proviruses by pseudotyping entire polytropic proviral transcripts and facilitating their infectious spread to new cells. However, the frequency of this occurrence, the kinetics, and the identity of mobilized endogenous proviruses was unclear. Here we find that these mobilized transcripts are detected after only one day of infection. They predominate over recombinant polytropic viruses early in infection, persist throughout the course of disease and are comprised of multiple different polytropic proviruses. Other endogenous retroviral elements such as intracisternal A particles (IAPs) were not detected. The integration of the endogenous transcripts into new cells could result in loss of transcriptional control and elevated expression which may facilitate pathogenesis, perhaps by contributing to the generation of polytropic recombinant viruses. PMID:27657834

Glial dysfunction in parkin null mice: effects of aging.

PubMed

Solano, Rosa M; Casarejos, Maria J; Menéndez-Cuervo, Jamie; Rodriguez-Navarro, Jose A; García de Yébenes, Justo; Mena, Maria A

2008-01-16

Parkin mutations in humans produce parkinsonism whose pathogenesis is related to impaired protein degradation, increased free radicals, and abnormal neurotransmitter release. The role of glia in parkin deficiency is little known. We cultured midbrain glia from wild-type (WT) and parkin knock-out (PK-KO) mice. After 18-20 d in vitro, PK-KO glial cultures had less astrocytes, more microglia, reduced proliferation, and increased proapoptotic protein expression. PK-KO glia had greater levels of intracellular glutathione (GSH), increased mRNA expression of the GSH-synthesizing enzyme gamma-glutamylcysteine synthetase, and greater glutathione S-transferase and lower glutathione peroxidase activities than WT. The reverse happened in glia cultured in serum-free defined medium (EF12) or in old cultures. PK-KO glia was more susceptible than WT to transference to EF12 or neurotoxins (1-methyl-4-phenylpyridinium, blockers of GSH synthesis or catalase, inhibitors of extracellular signal-regulated kinase 1/2 and phosphatidylinositol 3 kinases), aging of the culture, or combination of these insults. PK-KO glia was less susceptible than WT to Fe2+ plus H2O2 and less responsive to protection by deferoxamine. Old WT glia increased the expression of heat shock protein 70, but PK-KO did not. Glia conditioned medium (GCM) from PK-KO was less neuroprotective and had lower levels of GSH than WT. GCM from WT increased the levels of dopamine markers in midbrain neuronal cultures transferred to EF12 more efficiently than GCM from PK-KO, and the difference was corrected by supplementation with GSH. PK-KO-GCM was a less powerful suppressor of apoptosis and microglia in neuronal cultures. Our data prove that abnormal glial function is critical in parkin mutations, and its role increases with aging.

Inactivation of parkin by promoter methylation correlated with lymph node metastasis and genomic instability in nasopharyngeal carcinoma.

PubMed

Ni, Haifeng; Zhou, Zhen; Jiang, Bo; Yuan, Xiaoyang; Cao, Xiaolin; Huang, Guangwu; Li, Yong

2017-03-01

This study aimed to investigate the inactivation of the parkin gene by promoter methylation and its relationship with genome instability in nasopharyngeal carcinoma. Parkin was considered as a tumor suppressor gene in various types of cancers. However, its role in nasopharyngeal carcinoma is unexplored. Genomic instabilities were detected in nasopharyngeal carcinoma tissues by the random amplified polymorphic DNA. The methylation-specific polymerase chain reaction, semi-quantitative reverse transcription polymerase chain reaction, and immunohistochemical analysis were used to detect methylation and mRNA and protein expression of parkin in 54 cases of nasopharyngeal carcinoma tissues and 16 cases of normal nasopharyngeal epithelia tissues, and in 5 nasopharyngeal carcinoma cell lines (CNE1, CNE2, TWO3, C666, and HONE1) and 1 normal nasopharyngeal epithelia cell line (NP69). mRNA expression of parkin in CNE1 and CNE2 was analyzed before and after methyltransferase inhibitor 5-aza-2-deoxycytidine treatment. The relationship between promoter methylation and mRNA expression, demethylation and mRNA expression, and mRNA and protein expression of the gene and clinical factors and genomic instabilities were analyzed. The mRNA and protein expression levels were significantly reduced in 54 cases of human nasopharyngeal carcinoma compared with 16 cases of normal nasopharyngeal epithelia. Parkin-methylated cases showed significantly lower mRNA and protein expression levels compared with unmethylated cases. After 5-aza-2-deoxycytidine treatment, parkin mRNA expression was restored in CNE1 and CNE2; 92.59% (50/54) of nasopharyngeal carcinoma demonstrated genomic instability. Parkin is frequently inactivated by promoter methylation, and its mRNA and protein expression correlate with lymph node metastasis and genomic instability. Parkin deficiency probably promotes tumorigenesis in nasopharyngeal carcinoma.

Mitochondrial targeted HSP90 inhibitor Gamitrinib-TPP (G-TPP) induces PINK1/Parkin-dependent mitophagy.

PubMed

Fiesel, Fabienne C; James, Elle D; Hudec, Roman; Springer, Wolfdieter

2017-12-05

Loss-of-function mutations in PINK1 or PARKIN are associated with early-onset Parkinson's disease. Upon mitochondrial stress, PINK1 and Parkin together mediate a response that protects cells from the accumulation of harmful, damaged mitochondria. PINK1, the upstream kinase accumulates on the mitochondrial surface and recruits the E3 ubiquitin ligase Parkin on site to ubiquitylate substrate proteins. The joint activity of both to generate phosphorylated poly-ubiquitin chains on the mitochondrial surface induces the recruitment of autophagy receptors and eventually whole organelles are cleared by autophagy. While this pathway is generally accepted to occur upon chemical uncoupling of mitochondria, the (patho-) physiologic relevance has been questioned. However, few studies have indicated that PINK1 and Parkin are also activated upon accumulation of misfolded proteins in the mitochondrial lumen upon overexpression of ΔOTC (Ornithine transcarbamylase). Here, we used the mitochondrial targeted HSP90 inhibitor Gamitrinib-triphenylphosphonium (G-TPP), an anti-cancer agent, to chemically interfere with mitochondrial protein folding. G-TPP treatment induced PINK1 accumulation, ubiquitin phosphorylation at Ser65, Parkin activation and its recruitment to mitochondria was specific for mitochondrial HSP90 inhibition and largely independent of mitochondrial membrane depolarization. Mitophagy induction was observed by monitoring autophagy receptor recruitment and the mitoKeima reporter. Importantly, mitophagy was not only induced in cancer cells but also in primary human fibroblasts and thereof converted neurons. G-TPP treatment might represent a novel strategy to study PINK1 and Parkin-mediated mitochondrial quality control using a more physiologically relevant stress.

Phosphorylation by PINK1 Releases the UBL Domain and Initializes the Conformational Opening of the E3 Ubiquitin Ligase Parkin

PubMed Central

Moussaud-Lamodière, Elisabeth L.; Dourado, Daniel F. A. R.; Flores, Samuel C.; Springer, Wolfdieter

2014-01-01

Loss-of-function mutations in PINK1 or PARKIN are the most common causes of autosomal recessive Parkinson's disease. Both gene products, the Ser/Thr kinase PINK1 and the E3 Ubiquitin ligase Parkin, functionally cooperate in a mitochondrial quality control pathway. Upon stress, PINK1 activates Parkin and enables its translocation to and ubiquitination of damaged mitochondria to facilitate their clearance from the cell. Though PINK1-dependent phosphorylation of Ser65 is an important initial step, the molecular mechanisms underlying the activation of Parkin's enzymatic functions remain unclear. Using molecular modeling, we generated a complete structural model of human Parkin at all atom resolution. At steady state, the Ub ligase is maintained inactive in a closed, auto-inhibited conformation that results from intra-molecular interactions. Evidently, Parkin has to undergo major structural rearrangements in order to unleash its catalytic activity. As a spark, we have modeled PINK1-dependent Ser65 phosphorylation in silico and provide the first molecular dynamics simulation of Parkin conformations along a sequential unfolding pathway that could release its intertwined domains and enable its catalytic activity. We combined free (unbiased) molecular dynamics simulation, Monte Carlo algorithms, and minimal-biasing methods with cell-based high content imaging and biochemical assays. Phosphorylation of Ser65 results in widening of a newly defined cleft and dissociation of the regulatory N-terminal UBL domain. This motion propagates through further opening conformations that allow binding of an Ub-loaded E2 co-enzyme. Subsequent spatial reorientation of the catalytic centers of both enzymes might facilitate the transfer of the Ub moiety to charge Parkin. Our structure-function study provides the basis to elucidate regulatory mechanisms and activity of the neuroprotective Parkin. This may open up new avenues for the development of small molecule Parkin activators through

PINK1-Parkin alleviates metabolic stress induced by obesity in adipose tissue and in 3T3-L1 preadipocytes.

PubMed

Cui, Chen; Chen, Shihong; Qiao, Jingting; Qing, Li; Wang, Lingshu; He, Tianyi; Wang, Chuan; Liu, Fuqiang; Gong, Lei; Chen, Li; Hou, Xinguo

2018-04-06

Mitochondria play an important role in cellular metabolism and are closely related with metabolic stress. Recently, several studies have shown that mitophagy mediated by PTEN-induced putative kinase 1 (PINK1) and Parkin may play a critical role in clearing the damaged mitochondria and maintaining the overall balance of intracellular mitochondria in quality and quantity. A previous study showed that PINK1 and Parkin were overexpressed in adipose tissue in obese subjects. However, it is still unclear whether a direct relationship exists between obesity and mitophagy. In this study, we created a high-fat-diet (HFD)-induced obese mouse model and examined the expression of PINK1 and Parkin in adipose tissue using western blot and real-time quantitative PCR. After we confirmed that there is an interesting difference between regular-chow-fed mice and HFD-induced obese mice in the expression of PINK1 and Parkin in vivo, we further tested the expression of PINK1 and Parkin in 3T3-L1 preadipocytes in vitro by treating cells with palmitic acid (PA) to induce metabolic stress. To better understand the role of PINK1 and Parkin in metabolic stress, 3T3-L1 preadipocytes were transfected with small interfering RNA (siRNA) of PINK1 and Parkin followed by PA treatment. Our results showed that under lower concentrations of PA, PINK1 and Parkin can be activated and play a protective role in resisting the harmful effects of PA, including protecting the mitochondrial function and resisting cellular death, while under higher concentrations of PA, the expression of PINK1 and Parkin can be inhibited. These results suggest that PINK1-Parkin can protect mitochondrial function against metabolic stress induced by obesity or PA to a certain degree. Copyright © 2018 Elsevier Inc. All rights reserved.

Parkin elimination of mitochondria is important for maintenance of lens epithelial cell ROS levels and survival upon oxidative stress exposure.

PubMed

Brennan, Lisa; Khoury, Josef; Kantorow, Marc

2017-01-01

Age-related cataract is associated with oxidative stress and death of lens epithelial cells (LECs) whose survival is dependent on functional mitochondrial populations. Oxidative stress-induced depolarization/damage of LEC mitochondria results in increased reactive oxygen species (ROS) levels and cell death suggesting the need for a LEC mechanism to remove mitochondria depolarized/damaged upon oxidative stress exposure to prevent ROS release and LEC death. To date, a mechanism(s) for removal of depolarized/damaged LEC mitochondria has yet to be identified and the importance of eliminating oxidative stress-damaged mitochondria to prevent LEC ROS release and death has not been established. Here, we demonstrate that Parkin levels increase in LECs exposed to H 2 O 2 -oxidative stress. We establish that Parkin translocates to LEC mitochondria depolarized upon oxidative stress exposure and that Parkin recruits p62/SQSTM1 to depolarized LEC mitochondria. We demonstrate that translocation of Parkin results in the elimination of depolarized/damaged mitochondria and that Parkin clearance of LEC mitochondria is dependent on its ubiquitin ligase activity. Importantly, we demonstrate that Parkin elimination of damaged LEC mitochondria results in reduced ROS levels and increased survival upon oxidative stress exposure. These results establish that Parkin functions to eliminate LEC mitochondria depolarized/damaged upon oxidative stress exposure and that elimination of damaged mitochondria by Parkin is important for LEC homeostasis and survival. The data also suggest that mitochondrial quality control by Parkin could play a role in lens transparency. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Galectin-3 Inhibits Galectin-8/Parkin-Mediated Ubiquitination of Group A Streptococcus.

PubMed

Cheng, Yi-Lin; Wu, Yan-Wei; Kuo, Chih-Feng; Lu, Shiou-Ling; Liu, Fu-Tong; Anderson, Robert; Lin, Chiou-Feng; Liu, Yi-Ling; Wang, Wan-Yu; Chen, Ying-Da; Zheng, Po-Xing; Wu, Jiunn-Jong; Lin, Yee-Shin

2017-07-25

Group A streptococcus (GAS) is an important human pathogen that causes a wide variety of cutaneous and systemic infections. Although originally thought to be an extracellular bacterium, numerous studies have demonstrated that GAS can trigger internalization into nonimmune cells to escape from immune surveillance or antibiotic-mediated killing. Epithelial cells possess a defense mechanism involving autophagy-mediated targeting and killing of GAS within lysosome-fused autophagosomes. In endothelial cells, in contrast, we previously showed that autophagy is not sufficient for GAS killing. In the present study, we showed higher galectin-3 (Gal-3) expression and lower Gal-8 expression in endothelial cells than in epithelial cells. The recruitment of Gal-3 to GAS is higher and the recruitment of Gal-8 to GAS is lower in endothelial cells than in epithelial cells. We further showed that Gal-3 promotes GAS replication and diminishes the recruitment of Gal-8 and ubiquitin, the latter of which is a critical protein for autophagy sequestration. After knockdown of Gal-3 in endothelial cells, the colocalization of Gal-8, parkin, and ubiquitin-decorated GAS is significantly increased, as is the interaction of Gal-8 and parkin, an E3 ligase. Furthermore, inhibition of Gal-8 in epithelial cells attenuates recruitment of parkin; both Gal-8 and parkin contribute to ubiquitin recruitment and GAS elimination. Animal studies confirmed that Gal-3-knockout mice develop less-severe skin damage and that GAS replication can be detected only in the air pouch and not in organs and endothelial cells. These results demonstrate that Gal-3 inhibits ubiquitin recruitment by blocking Gal-8 and parkin recruitment, resulting in GAS replication in endothelial cells. IMPORTANCE In epithelial cells, GAS can be efficiently killed within the lysosome-fused autophaosome compartment. However, we previously showed that, in spite of LC-3 recruitment, the autophagic machinery is not sufficient for GAS killing

Doxorubicin-induced mitophagy and mitochondrial damage is associated with dysregulation of the PINK1/parkin pathway.

PubMed

Yin, Jian; Guo, Jiabin; Zhang, Qiang; Cui, Lan; Zhang, Li; Zhang, Tingfen; Zhao, Jun; Li, Jin; Middleton, Alistair; Carmichael, Paul L; Peng, Shuangqing

2018-09-01

The usefulness of doxorubicin (DOX), a potent anticancer agent, is limited by its cardiotoxicity. Mitochondria play a central role in DOX-induced cardiotoxicity though the precise mechanisms are still obscure. Increasing evidence indicates that excessive activation of mitophagy and mitochondrial dysfunction are key causal events leading to DOX-induced cardiac injury. The PINK1/parkin pathway has emerged as a critical pathway in regulation of mitophagy as well as mitochondrial function. The present study was aimed to investigate the role of PINK1/parkin pathway in DOX-induced mitochondrial damage and cardiotoxicity. Our results showed that DOX concentration-dependently induced cytotoxicity and mitochondrial toxic effects including mitochondrial superoxide accumulation, decreased mitochondrial membrane potential and mitochondrial DNA copy number, as well as mitochondrial ultrastructural alterations. DOX induced mitophagy as evidenced by increases of the markers of autophagosomes, LC3, Beclin 1, reduction of p62, and co-localization of LC3 in mitochondria. DOX activated PINK1/parkin pathway and promoted translocation of PINK1/parkin to mitochondria. Meanwhile, DOX inhibited the expression of PGC-1α and its downstream targets nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM), and reduced the expression of mitochondrial proteins. Inhibition of mitophagy by mdivi-1 was found to attenuate activation of the PINK1/parkin pathway by DOX and preserve mitochondrial biogenesis, consequently mitigating DOX-induced mitochondrial superoxide overproduction and mitochondrial dysfunction. Moreover, scavenging mitochondrial superoxide by Mito-tempo was also found to effectively attenuate activation of the PINK1/parkin pathway and rescue the cells from DOX-induced adverse effects. Taken together, these findings suggest that DOX-induced mitophagy and mitochondrial damage in cardiomyocytes are mediated, at least in part, by dysregulation of the PINK1

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

PubMed

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

2017-01-15

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

PINK1/Parkin-mediated mitophagy play a protective role in manganese induced apoptosis in SH-SY5Y cells.

PubMed

Zhang, Hong-Tao; Mi, Lan; Wang, Ting; Yuan, Lan; Li, Xue-Hui; Dong, Li-Sha; Zhao, Peng; Fu, Juan-Ling; Yao, Bi-Yun; Zhou, Zong-Can

2016-08-01

Manganese (Mn) as an environmental risk factor of Parkinson's disease (PD) is considered to cause manganism. Mitophagy is thought to play a key role in elimination the injured mitochondria. The goal of this paper was to explore whether the PINK1/Parkin-mediated mitophagy is activated and its role in Mn-induced mitochondrial dysfunction and cell death in SH-SY5Y cells. Here, we investigated effects of MnCl2 on ROS generation, mitochondrial membrane potential (MMP/ΔΨm) and apoptosis by FACS and examined PINK1/Parkin-mediated mitophagy by western-blotting and the co-localization of mitochondria and acidic lysosomes. Further, we explore the role of mitophagy in Mn-induced apoptosis by inhibition the mitophagy by knockdown Parkin level. Results show that MnCl2 dose-dependently caused ΔΨm decrease, ROS generation and apoptosis of dopaminergic SH-SY5Y cells. Moreover, Mn could induce mitophagy and PINK1/Parkin-mediated pathway was activated in SH-SY5Y cells. Transient transfection of Parkin siRNA knockdown the expressing level of parkin inhibited Mn-induced mitophagy and aggravated apoptosis of SH-SY5Y cells. In conclusion, our study demonstrated that Mn may induce PINK1/Parkin-mediated mitophagy, which may exert significant neuro-protective effect against Mn-induced dopaminergic neuronal cells apoptosis. Copyright © 2016 Elsevier B.V. All rights reserved.

UbMES and UbFluor: Novel probes for ring-between-ring (RBR) E3 ubiquitin ligase PARKIN.

PubMed

Park, Sungjin; Foote, Peter K; Krist, David T; Rice, Sarah E; Statsyuk, Alexander V

2017-10-06

Ring-between-ring (RBR) E3 ligases have been implicated in autoimmune disorders and neurodegenerative diseases. The functions of many RBR E3s are poorly defined, and their regulation is complex, involving post-translational modifications and allosteric regulation with other protein partners. The functional complexity of RBRs, coupled with the complexity of the native ubiquitination reaction that requires ATP and E1 and E2 enzymes, makes it difficult to study these ligases for basic research and therapeutic purposes. To address this challenge, we developed novel chemical probes, ubiquitin C-terminal fluorescein thioesters UbMES and UbFluor, to qualitatively and quantitatively assess the activity of the RBR E3 ligase PARKIN in a simple experimental setup and in real time using fluorescence polarization. First, we confirmed that PARKIN does not require an E2 enzyme for substrate ubiquitination, lysine selection, and polyubiquitin chain formation. Second, we confirmed that UbFluor quantitatively detects naturally occurring activation states of PARKIN caused by Ser 65 phosphorylation (pPARKIN) and phosphorylated ubiquitin (pUb). Third, we showed that both pUb and the ubiquitin-accepting substrate contribute to maximal pPARKIN ubiquitin conjugation turnover. pUb enhances the transthiolation step, whereas the substrate clears the pPARKIN∼Ub thioester intermediate. Finally, we established that UbFluor can quantify activation or inhibition of PARKIN by structural mutations. These results demonstrate the feasibility of using UbFluor for quantitative studies of the biochemistry of RBR E3s and for high-throughput screening of small-molecule activators or inhibitors of PARKIN and other RBR E3 ligases. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Linking a compound-heterozygous Parkin mutant (Q311R and A371T) to Parkinson's disease by using proteomic and molecular approaches.

PubMed

Ozgul, Sinem; Kasap, Murat; Akpinar, Gurler; Kanli, Aylin; Güzel, Nil; Karaosmanoglu, Kübra; Baykal, Ahmet Tarik; Iseri, Pervin

2015-01-01

Parkin is an E3-protein ubiquitin ligase, which plays an important role as a scavenger in cell metabolism. Since the discovery of the link between Parkin and Parkinson's disease, Parkin was placed in the center of Parkinson's disease research. Previously, we isolated a mutant form of the Parkin protein (Q311R and A371T) from a Parkinson's disease patient. In this study, we aimed at characterizing this mutant Parkin protein by using biochemical and proteomic approaches. We used neuroblastoma cells (SH-SY5Y) as our model and created two inducible cell lines that expressed the wild type and the mutant Parkin proteins. We first investigated the effect of expressing both the wild type and the mutant Parkin proteins on the overall proteome by using 2D-DIGE approach. The experiments yielded the identification of 22 differentially regulated proteins, of which 13 were regulated in the mutant Parkin expressing cells. Classification of the identified proteins based on biological process and molecular function revealed that the majority of the regulated proteins belonged to protein folding and energy metabolism. Ingenuity Pathway Analysis predicted the presence of a link between the regulated proteins of the mutant Parkin expressing cells and Parkinson's disease. We also performed biochemical characterization studies on the wild type and the mutant Parkin proteins to make sense out of the differences observed at the proteome level. Both proteins displayed biological activity, had similar stabilities and localized similarly to the cytoplasm and the nucleus in SH-SY5Y cells. The mutant protein, however, was cut by a protease and subjected to a post-translational modification. The observed differences at the proteome level might be due to the differences in processing of the mutant Parkin protein. Overall, we were able to create a possible link between a pair of Parkin mutations to its pertinent disease by using 2D-DIGE in combination with biochemical and molecular approaches

Guanabenz promotes neuronal survival via enhancement of ATF4 and parkin expression in models of Parkinson disease.

PubMed

Sun, Xiaotian; Aimé, Pascaline; Dai, David; Ramalingam, Nagendran; Crary, John F; Burke, Robert E; Greene, Lloyd A; Levy, Oren A

2018-05-01

Reduced function of parkin appears to be a central pathogenic event in Parkinson disease (PD). Increasing parkin levels enhances survival in models of PD-related neuronal death and is a promising therapeutic objective. Previously, we demonstrated that the transcription factor ATF4 promotes survival in response to PD-mimetic stressors by maintaining parkin levels. ATF4 translation is up-regulated by phosphorylation of the translation initiation factor eIF2α. The small molecule guanabenz enhances eIF2α phosphorylation by blocking the function of GADD34, a regulatory protein that promotes eIF2α dephosphorylation. We tested the hypothesis that guanabenz, by inhibiting GADD34 and consequently increasing eIF2α phosphorylation and elevating ATF4, would improve survival in models of PD by up-regulating parkin. We found that GADD34 is strongly induced by 6-OHDA, and that GADD34 localization is dramatically altered in dopaminergic substantia nigra neurons in PD cases. We further demonstrated that guanabenz attenuates 6-hydroxydopamine (6-OHDA) induced cell death of differentiated PC12 cells and primary ventral midbrain dopaminergic neurons in culture, and of dopaminergic neurons in the substantia nigra of mice. In culture models, guanabenz also increases eIF2α phosphorylation and ATF4 and parkin levels in response to 6-OHDA. Furthermore, if either ATF4 or parkin is silenced, then the protective effect of guanabenz is lost. We also found similar results in a distinct model of neuronal death: primary cultures of cortical neurons treated with the topoisomerase I inhibitor camptothecin, in which guanabenz limited camptothecin-induced neuronal death in an ATF4- and parkin-dependent manner. In summary, our data suggest that guanabenz and other GADD34 inhibitors could be used as therapeutic agents to boost parkin levels and thereby slow neurodegeneration in PD and other neurodegenerative conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

PINK1/Parkin-mediated mitophagy alleviates chlorpyrifos-induced apoptosis in SH-SY5Y cells.

PubMed

Dai, Hongmei; Deng, Yuanying; Zhang, Jie; Han, Hailong; Zhao, Mingyi; Li, Ying; Zhang, Chen; Tian, Jing; Bing, Guoying; Zhao, Lingling

2015-08-06

Chlorpyrifos (CPF) is one of the most widely used organophosphorous insecticides. There are links between CPF exposure and neurological disorders. Mitochondrial damage has been implicated to play a key role in CPF-induced neurotoxicity. Mitophagy, the selective autophagic elimination of mitochondria, is an important mitochondrial quality control mechanism. However, the role of mitophagy in CPF-induced neurotoxicity remains unclear. In this study, CPF-caused mitochondrial damage, role and mechanism of mitophagy on CPF-induced neuroapoptosis were extensively studied by using SH-SY5Y cells. We showed that CPF treatment caused mitochondrial fragmentation, excessive ROS generation and mitochondrial depolarization, thus led to cell apoptosis. Moreover, CPF treatment also resulted in increased colocalizaton of mitochondria with LC3, decreased levels of mitochondrial proteins, PINK1 stabilization and mitochondrial accumulation of Parkin. These data suggested that CPF treatment induced PINK1/Parkin-mediated mitophagy in SH-SY5Y cells. Furthermore, knockdown of Parkin dramatically increased CPF-induced neuroapoptosis. On the other hand, overexpression of Parkin markedly alleviated CPF-induced SH-SY5Y cell apoptosis. Together, these findings implicate a protective role of PINK1/Parkin-mediated mitophagy against neuroapoptosis and that enhancing mitophagy provides a potential therapeutic strategy for CPF-induced neurological disorders. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

HSP72 is a mitochondrial stress sensor critical for Parkin action, oxidative metabolism, and insulin sensitivity in skeletal muscle.

PubMed

Drew, Brian G; Ribas, Vicente; Le, Jamie A; Henstridge, Darren C; Phun, Jennifer; Zhou, Zhenqi; Soleymani, Teo; Daraei, Pedram; Sitz, Daniel; Vergnes, Laurent; Wanagat, Jonathan; Reue, Karen; Febbraio, Mark A; Hevener, Andrea L

2014-05-01

Increased heat shock protein (HSP) 72 expression in skeletal muscle prevents obesity and glucose intolerance in mice, although the underlying mechanisms of this observation are largely unresolved. Herein we show that HSP72 is a critical regulator of stress-induced mitochondrial triage signaling since Parkin, an E3 ubiquitin ligase known to regulate mitophagy, was unable to ubiquitinate and control its own protein expression or that of its central target mitofusin (Mfn) in the absence of HSP72. In wild-type cells, we show that HSP72 rapidly translocates to depolarized mitochondria prior to Parkin recruitment and immunoprecipitates with both Parkin and Mfn2 only after specific mitochondrial insult. In HSP72 knockout mice, impaired Parkin action was associated with retention of enlarged, dysmorphic mitochondria and paralleled by reduced muscle respiratory capacity, lipid accumulation, and muscle insulin resistance. Reduced oxygen consumption and impaired insulin action were recapitulated in Parkin-null myotubes, confirming a role for the HSP72-Parkin axis in the regulation of muscle insulin sensitivity. These data suggest that strategies to maintain HSP72 may provide therapeutic benefit to enhance mitochondrial quality and insulin action to ameliorate complications associated with metabolic diseases, including type 2 diabetes.

Friend and Moloney murine leukemia viruses specifically recombine with different endogenous retroviral sequences to generate mink cell focus-forming viruses.

PubMed

Evans, L H; Cloyd, M W

1985-01-01

A group of mink cell focus-forming (MCF) viruses was derived by inoculation of NFS/N mice with Moloney murine leukemia virus (Mo-MuLV 1387) and was compared to a similarly derived group of MCF viruses from mice inoculated with Friend MuLV (Fr-MuLV 57). Antigenic analyses using monoclonal antibodies specific for MCF virus and xenotropic MuLV envelope proteins and genomic structural analyses by RNase T1-resistant oligonucleotide finger-printing indicated that the Moloney and Friend MCF viruses arose by recombination of the respective ecotropic MuLVs with different endogenous retrovirus sequences of NFS mice.

The Naïve Murine Cornea as a Model System to Identify Novel Endogenous Regulators of Lymphangiogenesis: TRAIL and rtPA.

PubMed

Regenfuß, Birgit; Dreisow, Marie-Luise; Hos, Deniz; Masli, Sharmila; Bock, Felix; Cursiefen, Claus

2015-06-01

In the murine cornea, which is an established model for analyzing pathologic lymphatic vessel growth, phenotypic heterogeneity of the endogenous lymphatic vessels in the limbus of the cornea was previously described. In this study, the cornea of BALB/c, C57BL/6, and FVB mice with different limbal lymphangiogenic phenotypes was analyzed to identify novel candidates potentially influencing lymphatic vessel growth. Pathway specific expression analysis of the cornea was performed to identify novel candidate genes. Corneal protein expression of the respective candidates was analyzed by fluorescent immunohistochemistry. The effect of the candidates on proliferation of human dermal lymphatic endothelial cells (HDLECs) was analyzed by BrdU proliferation ELISA. Thirteen genes were differentially regulated in corneas of mouse strains with more endogenous limbal lymphatic vessels (high-lymphangiogenic) (C57BL/6) compared to mouse strains with less endogenous limbal lymphatic vessels (low-lymphangiogenic) (BALB/c, FVB). Two candidates, Tumor necrosis factor (ligand) superfamily member 10 (Tnfsf10/Trail) and Plasminogen activator, tissue (Plat/tPA) were expressed in the cornea of BALB/c and C57BL/6 mice on the protein level. In vitro, Trail and recombinant tPA inhibited the proliferation of human dermal lymphatic endothelial cells. Molecular analysis of the naive cornea in mouse strains with different limbal lymphatic phenotypes is a valuable model to identify novel endogenous regulators of lymphangiogenesis.

Compensatory premotor activity during affective face processing in subclinical carriers of a single mutant Parkin allele.

PubMed

Anders, Silke; Sack, Benjamin; Pohl, Anna; Münte, Thomas; Pramstaller, Peter; Klein, Christine; Binkofski, Ferdinand

2012-04-01

Patients with Parkinson's disease suffer from significant motor impairments and accompanying cognitive and affective dysfunction due to progressive disturbances of basal ganglia-cortical gating loops. Parkinson's disease has a long presymptomatic stage, which indicates a substantial capacity of the human brain to compensate for dopaminergic nerve degeneration before clinical manifestation of the disease. Neuroimaging studies provide evidence that increased motor-related cortical activity can compensate for progressive dopaminergic nerve degeneration in carriers of a single mutant Parkin or PINK1 gene, who show a mild but significant reduction of dopamine metabolism in the basal ganglia in the complete absence of clinical motor signs. However, it is currently unknown whether similar compensatory mechanisms are effective in non-motor basal ganglia-cortical gating loops. Here, we ask whether asymptomatic Parkin mutation carriers show altered patterns of brain activity during processing of facial gestures, and whether this might compensate for latent facial emotion recognition deficits. Current theories in social neuroscience assume that execution and perception of facial gestures are linked by a special class of visuomotor neurons ('mirror neurons') in the ventrolateral premotor cortex/pars opercularis of the inferior frontal gyrus (Brodmann area 44/6). We hypothesized that asymptomatic Parkin mutation carriers would show increased activity in this area during processing of affective facial gestures, replicating the compensatory motor effects that have previously been observed in these individuals. Additionally, Parkin mutation carriers might show altered activity in other basal ganglia-cortical gating loops. Eight asymptomatic heterozygous Parkin mutation carriers and eight matched controls underwent functional magnetic resonance imaging and a subsequent facial emotion recognition task. As predicted, Parkin mutation carriers showed significantly stronger activity in

Compensatory premotor activity during affective face processing in subclinical carriers of a single mutant Parkin allele

PubMed Central

Sack, Benjamin; Pohl, Anna; Münte, Thomas; Pramstaller, Peter; Klein, Christine; Binkofski, Ferdinand

2012-01-01

Patients with Parkinson's disease suffer from significant motor impairments and accompanying cognitive and affective dysfunction due to progressive disturbances of basal ganglia–cortical gating loops. Parkinson's disease has a long presymptomatic stage, which indicates a substantial capacity of the human brain to compensate for dopaminergic nerve degeneration before clinical manifestation of the disease. Neuroimaging studies provide evidence that increased motor-related cortical activity can compensate for progressive dopaminergic nerve degeneration in carriers of a single mutant Parkin or PINK1 gene, who show a mild but significant reduction of dopamine metabolism in the basal ganglia in the complete absence of clinical motor signs. However, it is currently unknown whether similar compensatory mechanisms are effective in non-motor basal ganglia–cortical gating loops. Here, we ask whether asymptomatic Parkin mutation carriers show altered patterns of brain activity during processing of facial gestures, and whether this might compensate for latent facial emotion recognition deficits. Current theories in social neuroscience assume that execution and perception of facial gestures are linked by a special class of visuomotor neurons (‘mirror neurons’) in the ventrolateral premotor cortex/pars opercularis of the inferior frontal gyrus (Brodmann area 44/6). We hypothesized that asymptomatic Parkin mutation carriers would show increased activity in this area during processing of affective facial gestures, replicating the compensatory motor effects that have previously been observed in these individuals. Additionally, Parkin mutation carriers might show altered activity in other basal ganglia–cortical gating loops. Eight asymptomatic heterozygous Parkin mutation carriers and eight matched controls underwent functional magnetic resonance imaging and a subsequent facial emotion recognition task. As predicted, Parkin mutation carriers showed significantly stronger

PINK1, Parkin, and Mitochondrial Quality Control: What can we Learn about Parkinson's Disease Pathobiology?

PubMed

Truban, Dominika; Hou, Xu; Caulfield, Thomas R; Fiesel, Fabienne C; Springer, Wolfdieter

2017-01-01

The first clinical description of Parkinson's disease (PD) will embrace its two century anniversary in 2017. For the past 30 years, mitochondrial dysfunction has been hypothesized to play a central role in the pathobiology of this devastating neurodegenerative disease. The identifications of mutations in genes encoding PINK1 (PTEN-induced kinase 1) and Parkin (E3 ubiquitin ligase) in familial PD and their functional association with mitochondrial quality control provided further support to this hypothesis. Recent research focused mainly on their key involvement in the clearance of damaged mitochondria, a process known as mitophagy. It has become evident that there are many other aspects of this complex regulated, multifaceted pathway that provides neuroprotection. As such, numerous additional factors that impact PINK1/Parkin have already been identified including genes involved in other forms of PD. A great pathogenic overlap amongst different forms of familial, environmental and even sporadic disease is emerging that potentially converges at the level of mitochondrial quality control. Tremendous efforts now seek to further detail the roles and exploit PINK1 and Parkin, their upstream regulators and downstream signaling pathways for future translation. This review summarizes the latest findings on PINK1/Parkin-directed mitochondrial quality control, its integration and cross-talk with other disease factors and pathways as well as the implications for idiopathic PD. In addition, we highlight novel avenues for the development of biomarkers and disease-modifying therapies that are based on a detailed understanding of the PINK1/Parkin pathway.

Parkin modulates expression of HIF-1α and HIF-3α during hypoxia in gliobastoma-derived cell lines in vitro.

PubMed

Maugeri, Grazia; D'Amico, Agata Grazia; Reitano, Rita; Saccone, Salvatore; Federico, Concetta; Cavallaro, Sebastiano; D'Agata, Velia

2016-06-01

Mutation of the Parkin gene causes an autosomal recessive juvenile-onset form of Parkinson's disease. However, recently, it has been also linked to a wide variety of malignancies, including glioblastoma multiforme (GBM). In this pathology, Parkin exhibits a tumor suppressor role by mitigating the proliferation rate in both in vitro and in vivo models. However, Parkin involvement in the hypoxic process has not as yet been investigated. GBM is the most common and aggressive primary brain tumor in adults and is characterized by hypoxic areas. The low oxygen supply causes the expression of hypoxia-inducible factors (HIFs) leading to an accumulation of pro-angiogenic factors and tumoral invasiveness. We assess the relationship between Parkin and two HIFs expressed during hypoxic conditions, namely HIF-1α and HIF-3α. Our data show that Parkin is downregulated under hypoxia and that it interferes with HIF expression based on cellular oxygen tension. These results suggest a role for the involvement of Parkin in GBM, although further studies will be needed to understand the mechanism by which it modulates HIF-1α and HIF-3α expression.

MiT/TFE transcription factors are activated during mitophagy downstream of Parkin and Atg5.

PubMed

Nezich, Catherine L; Wang, Chunxin; Fogel, Adam I; Youle, Richard J

2015-08-03

The kinase PINK1 and ubiquitin ligase Parkin can regulate the selective elimination of damaged mitochondria through autophagy (mitophagy). Because of the demand on lysosomal function by mitophagy, we investigated a role for the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, in this process. We show that during mitophagy TFEB translocates to the nucleus and displays transcriptional activity in a PINK1- and Parkin-dependent manner. MITF and TFE3, homologues of TFEB belonging to the same microphthalmia/transcription factor E (MiT/TFE) family, are similarly regulated during mitophagy. Unlike TFEB translocation after starvation-induced mammalian target of rapamycin complex 1 inhibition, Parkin-mediated TFEB relocalization required Atg9A and Atg5 activity. However, constitutively active Rag guanosine triphosphatases prevented TFEB translocation during mitophagy, suggesting cross talk between these two MiT/TFE activation pathways. Analysis of clustered regularly interspaced short palindromic repeats-generated TFEB/MITF/TFE3/TFEC single, double, and triple knockout cell lines revealed that these proteins partly facilitate Parkin-mediated mitochondrial clearance. These results illuminate a pathway leading to MiT/TFE transcription factor activation, distinct from starvation-induced autophagy, which occurs during mitophagy.

Enteric serotonin and oxytocin: endogenous regulation of severity in a murine model of necrotizing enterocolitis.

PubMed

Gross Margolis, Kara; Vittorio, Jennifer; Talavera, Maria; Gluck, Karen; Li, Zhishan; Iuga, Alina; Stevanovic, Korey; Saurman, Virginia; Israelyan, Narek; Welch, Martha G; Gershon, Michael D

2017-11-01

Necrotizing enterocolitis (NEC), a gastrointestinal inflammatory disease of unknown etiology that may also affect the liver, causes a great deal of morbidity and mortality in premature infants. We tested the hypothesis that signaling molecules, which are endogenous to the bowel, regulate the severity of intestinal and hepatic damage in an established murine NEC model. Specifically, we postulated that mucosal serotonin (5-HT), which is proinflammatory, would exacerbate experimental NEC and that oxytocin (OT), which is present in enteric neurons and is anti-inflammatory, would oppose it. Genetic deletion of the 5-HT transporter (SERT), which increases and prolongs effects of 5-HT, was found to increase the severity of systemic manifestations, intestinal inflammation, and associated hepatotoxicity of experimental NEC. In contrast, genetic deletion of tryptophan hydroxylase 1 (TPH1), which is responsible for 5-HT biosynthesis in enterochromaffin (EC) cells of the intestinal mucosa, and TPH inhibition with LP-920540 both decrease the severity of experimental NEC in the small intestine and liver. These observations suggest that 5-HT from EC cells helps to drive the inflammatory damage to the gut and liver that occurs in the murine NEC model. Administration of OT decreased, while the OT receptor antagonist atosiban exacerbated, the intestinal inflammation of experimental NEC. Data from the current investigation are consistent with the tested hypotheses-that the enteric signaling molecules, 5-HT (positively) and OT (negatively) regulate severity of inflammation in a mouse model of NEC. Moreover, we suggest that mucosally restricted inhibition of 5-HT biosynthesis and/or administration of OT may be useful in the treatment of NEC. NEW & NOTEWORTHY Serotonin (5-HT) and oxytocin reciprocally regulate the severity of intestinal inflammation and hepatotoxicity in a murine model of necrotizing enterocolitis (NEC). Selective depletion of mucosal 5-HT through genetic deletion or

A comprehensive computational study on pathogenic mis-sense mutations spanning the RING2 and REP domains of Parkin protein.

PubMed

Biswas, Ria; Bagchi, Angshuman

2017-04-30

Various mutations in PARK2 gene, which encodes the protein parkin, are significantly associated with the onset of autosomal recessive juvenile Parkinson (ARJP) in neuronal cells. Parkin is a multi domain protein, the N-terminal part contains the Ubl and the C-terminal part consists of four zinc coordinating domains, viz., RING0, RING1, in between ring (IBR) and RING2. Disease mutations are spread over all the domains of Parkin, although mutations in some regions may affect the functionality of Parkin more adversely. The mutations in the RING2 domain are seen to abolish the neuroprotective E3 ligase activity of Parkin. In this current work, we carried out detailed in silico analysis to study the extent of pathogenicity of mutations spanning the Parkin RING2 domain and the adjoining REP region by SIFT, Mutation Accessor, PolyPhen2, SNPs and GO, GV/GD and I-mutant. To study the structural and functional implications of these mutations on RING2-REP domain of Parkin, we studied the solvent accessibility (SASA/RSA), hydrophobicity, intra-molecular hydrogen bonding profile and domain analysis by various computational tools. Finally, we analysed the interaction energy profiles of the mutants and compared them to the wild type protein using Discovery studio 2.5. By comparing the various analyses it could be safely concluded that except P437L and A379V mutations, all other mutations were potentially deleterious affecting various structural aspects of RING2 domain architecture. This study is based purely on computational approach which has the potential to identify disease mutations and the information could further be used in treatment of diseases and prognosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Parkin-Dependent Degradation of the F-Box Protein Fbw7β Promotes Neuronal Survival in Response to Oxidative Stress by Stabilizing Mcl-1

PubMed Central

Ekholm-Reed, Susanna; Goldberg, Matthew S.; Schlossmacher, Michael G.

2013-01-01

Parkinson's disease (PD) is characterized by progressive loss of midbrain dopaminergic neurons resulting in motor dysfunction. While most PD is sporadic in nature, a significant subset can be linked to either dominant or recessive germ line mutations. PARK2, encoding the ubiquitin ligase parkin, is the most frequently mutated gene in hereditary Parkinson's disease. Here, we present evidence for a neuronal ubiquitin ligase cascade involving parkin and the multisubunit ubiquitin ligase SCFFbw7β. Specifically, parkin targets the SCF substrate adapter Fbw7β for proteasomal degradation. Furthermore, we show that the physiological role of parkin-mediated regulation of Fbw7β levels is the stabilization of the mitochondrial prosurvival factor Mcl-1, an SCFFbw7β target in neurons. We show that neurons depleted of parkin become acutely sensitive to oxidative stress due to an inability to maintain adequate levels of Mcl-1. Therefore, loss of parkin function through biallelic mutation of PARK2 may lead to death of dopaminergic neurons through unregulated SCFFbw7β-mediated ubiquitylation-dependent proteolysis of Mcl-1. PMID:23858059

PINK1, Parkin, and Mitochondrial Quality Control: What can we Learn about Parkinson’s Disease Pathobiology?

PubMed Central

Truban, Dominika; Hou, Xu; Caulfield, Thomas R.; Fiesel, Fabienne C.; Springer, Wolfdieter

2016-01-01

The first clinical description of Parkinson’s disease (PD) will embrace its two century anniversary in 2017. For the past 30 years, mitochondrial dysfunction has been hypothesized to play a central role in the pathobiology of this devastating neurodegenerative disease. The identifications of mutations in genes encoding PINK1 (PTEN-induced kinase 1) and Parkin (E3 ubiquitin ligase) in familial PD and their functional association with mitochondrial quality control provided further support to this hypothesis. Recent research focused mainly on their key involvement in the clearance of damaged mitochondria, a process known as mitophagy. It has become evident that there are many other aspects of this complex regulated, multifaceted pathway that provides neuroprotection. As such, numerous additional factors that impact PINK1/Parkin have already been identified including genes involved in other forms of PD. A great pathogenic overlap amongst different forms of familial, environmental and even sporadic disease is emerging that potentially converges at the level of mitochondrial quality control. Tremendous efforts now seek to further detail the roles and exploit PINK1 and Parkin, their upstream regulators and downstream signaling pathways for future translation. This review summarizes the latest findings on PINK1/Parkin-directed mitochondrial quality control, its integration and cross-talk with other disease factors and pathways as well as the implications for idiopathic PD. In addition, we highlight novel avenues for the development of biomarkers and disease-modifying therapies that are based on a detailed understanding of the PINK1/Parkin pathway. PMID:27911343

Drosophila CHIP protects against mitochondrial dysfunction by acting downstream of Pink1 in parallel with Parkin.

PubMed

Chen, Jia; Xue, Jin; Ruan, Jingsong; Zhao, Juan; Tang, Beisha; Duan, Ranhui

2017-12-01

Mitochondrial kinase PTEN-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase Parkin function in a common pathway to regulate mitochondrial homeostasis contributing to the pathogenesis of Parkinson disease. The carboxyl terminus of Hsc70-interacting protein (CHIP) acts as a heat shock protein 70/heat shock protein 90 cochaperone to mediate protein folding or as an E3 ubiquitin ligase to target proteins for degradation. In this study, overexpression of Drosophila CHIP suppressed a range of Pink1 mutant phenotypes in flies, including abnormal wing posture, thoracic indentation, locomotion defects, muscle degeneration, and loss of dopaminergic neurons. Mitochondrial defects of Pink1 mutant, such as excessive fusion, reduced ATP content, and crista disorganization, were rescued by CHIP but not its ligase-dead mutants. Similar phenotypes and mitochondrial impairment were ameliorated in Parkin mutant flies by wild-type CHIP. Inactivation of CHIP with null fly mutants resulted in mitochondrial defects, such as reduced thoracic ATP content at 3 d old, decreased thoracic mitochondrial DNA content, and defective mitochondrial morphology at 60 d old. CHIP mutants did not exacerbate the phenotypes of Pink1 mutant flies but markedly shortened the life span of Parkin mutant flies. These results indicate that CHIP is involved in mitochondrial integrity and may act downstream of Pink1 in parallel with Parkin.-Chen, J., Xue, J., Ruan, J., Zhao, J., Tang, B., Duan, R. Drosophila CHIP protects against mitochondrial dysfunction by acting downstream of Pink1 in parallel with Parkin. © FASEB.

The parkin Mutant Phenotype in the Fly Is Largely Rescued by Metal-Responsive Transcription Factor (MTF-1) ▿ †

PubMed Central

Saini, Nidhi; Georgiev, Oleg; Schaffner, Walter

2011-01-01

The gene for Parkin, an E3 ubiquitin ligase, is mutated in some familial forms of Parkinson's disease, a severe neurodegenerative disorder. A homozygous mutant of the Drosophila ortholog of human parkin is viable but results in severe motoric impairment including an inability to fly, female and male sterility, and a decreased life span. We show here that a double mutant of the genes for Parkin and the metal-responsive transcription factor 1 (MTF-1) is not viable. MTF-1, which is conserved from insects to mammals, is a key regulator of heavy metal homeostasis and detoxification and plays additional roles in other stress conditions, notably oxidative stress. In contrast to the synthetic lethality of the double mutant, elevated expression of MTF-1 dramatically ameliorates the parkin mutant phenotype, as evidenced by a prolonged life span, motoric improvement including short flight episodes, and female fertility. At the cellular level, muscle and mitochondrial structures are substantially improved. A beneficial effect is also seen with a transgene encoding human MTF-1. We propose that Parkin and MTF-1 provide complementary functions in metal homeostasis, oxidative stress and other cellular stress responses. Our findings also raise the possibility that MTF-1 gene polymorphisms in humans could affect the severity of Parkinson's disease. PMID:21383066

AMBRA1 is able to induce mitophagy via LC3 binding, regardless of PARKIN and p62/SQSTM1

PubMed Central

Strappazzon, F; Nazio, F; Corrado, M; Cianfanelli, V; Romagnoli, A; Fimia, G M; Campello, S; Nardacci, R; Piacentini, M; Campanella, M; Cecconi, F

2015-01-01

Damaged mitochondria are eliminated by mitophagy, a selective form of autophagy whose dysfunction associates with neurodegenerative diseases. PINK1, PARKIN and p62/SQTMS1 have been shown to regulate mitophagy, leaving hitherto ill-defined the contribution by key players in ‘general' autophagy. In basal conditions, a pool of AMBRA1 – an upstream autophagy regulator and a PARKIN interactor – is present at the mitochondria, where its pro-autophagic activity is inhibited by Bcl-2. Here we show that, upon mitophagy induction, AMBRA1 binds the autophagosome adapter LC3 through a LIR (LC3 interacting region) motif, this interaction being crucial for regulating both canonical PARKIN-dependent and -independent mitochondrial clearance. Moreover, forcing AMBRA1 localization to the outer mitochondrial membrane unleashes a massive PARKIN- and p62-independent but LC3-dependent mitophagy. These results highlight a novel role for AMBRA1 as a powerful mitophagy regulator, through both canonical or noncanonical pathways. PMID:25215947

AMBRA1 is able to induce mitophagy via LC3 binding, regardless of PARKIN and p62/SQSTM1.

PubMed

Strappazzon, F; Nazio, F; Corrado, M; Cianfanelli, V; Romagnoli, A; Fimia, G M; Campello, S; Nardacci, R; Piacentini, M; Campanella, M; Cecconi, F

2015-03-01

Damaged mitochondria are eliminated by mitophagy, a selective form of autophagy whose dysfunction associates with neurodegenerative diseases. PINK1, PARKIN and p62/SQTMS1 have been shown to regulate mitophagy, leaving hitherto ill-defined the contribution by key players in 'general' autophagy. In basal conditions, a pool of AMBRA1 - an upstream autophagy regulator and a PARKIN interactor - is present at the mitochondria, where its pro-autophagic activity is inhibited by Bcl-2. Here we show that, upon mitophagy induction, AMBRA1 binds the autophagosome adapter LC3 through a LIR (LC3 interacting region) motif, this interaction being crucial for regulating both canonical PARKIN-dependent and -independent mitochondrial clearance. Moreover, forcing AMBRA1 localization to the outer mitochondrial membrane unleashes a massive PARKIN- and p62-independent but LC3-dependent mitophagy. These results highlight a novel role for AMBRA1 as a powerful mitophagy regulator, through both canonical or noncanonical pathways.

Changes in the expression of neurotransmitter receptors in Parkin and DJ-1 knockout mice--A quantitative multireceptor study.

PubMed

Cremer, J N; Amunts, K; Schleicher, A; Palomero-Gallagher, N; Piel, M; Rösch, F; Zilles, K

2015-12-17

Parkinson's disease (PD) is a well-characterized neurological disorder with regard to its neuropathological and symptomatic appearance. At the genetic level, mutations of particular genes, e.g. Parkin and DJ-1, were found in human hereditary PD with early onset. Neurotransmitter receptors constitute decisive elements in neural signal transduction. Furthermore, since they are often altered in neurological and psychiatric diseases, receptors have been successful targets for pharmacological agents. However, the consequences of PD-associated gene mutations on the expression of transmitter receptors are largely unknown. Therefore, we studied the expression of 16 different receptor binding sites of the neurotransmitters glutamate, GABA, acetylcholine, adrenaline, serotonin, dopamine and adenosine by means of quantitative receptor autoradiography in Parkin and DJ-1 knockout mice. These knockout mice exhibit electrophysiological and behavioral deficits, but do not show the typical dopaminergic cell loss. We demonstrated differential changes of binding site densities in eleven brain regions. Most prominently, we found an up-regulation of GABA(B) and kainate receptor densities in numerous cortical areas of Parkin and DJ-1 knockout mice, as well as increased NMDA but decreased AMPA receptor densities in different brain regions of the Parkin knockout mice. The alterations of three different glutamate receptor types may indicate the potential relevance of the glutamatergic system in the pathogenesis of PD. Furthermore, the cholinergic M1, M2 and nicotinic receptors as well as the adrenergic α2 and the adenosine A(2A) receptors showed differentially increased densities in Parkin and DJ-1 knockout mice. Taken together, knockout of the PD-associated genes Parkin or DJ-1 results in differential changes of neurotransmitter receptor densities, highlighting a possible role of altered non-dopaminergic, and in particular of glutamatergic neurotransmission in PD pathogenesis. Copyright

Mitophagy controls beige adipocyte maintenance through a Parkin-dependent and UCP1-independent mechanism.

PubMed

Lu, Xiaodan; Altshuler-Keylin, Svetlana; Wang, Qiang; Chen, Yong; Henrique Sponton, Carlos; Ikeda, Kenji; Maretich, Pema; Yoneshiro, Takeshi; Kajimura, Shingo

2018-04-24

Beige adipocytes are an inducible form of mitochondria-enriched thermogenic adipocytes that emerge in response to external stimuli, such as chronic cold exposure. We have previously shown that after the withdrawal of external stimuli, beige adipocytes directly acquire a white fat-like phenotype through autophagy-mediated mitochondrial degradation. We investigated the upstream pathway that mediates mitochondrial clearance and report that Parkin-mediated mitophagy plays a key role in the beige-to-white adipocyte transition. Mice genetically deficient in Park2 showed reduced mitochondrial degradation and retained thermogenic beige adipocytes even after the withdrawal of external stimuli. Norepinephrine signaling through the PKA pathway inhibited the recruitment of Parkin protein to mitochondria in beige adipocytes. However, mitochondrial proton uncoupling by uncoupling protein 1 (UCP1) was dispensable for Parkin recruitment and beige adipocyte maintenance. These results suggest a physiological mechanism by which external cues control mitochondrial homeostasis in thermogenic fat cells through mitophagy. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Minocycline protects, rescues and prevents knockdown transgenic parkin Drosophila against paraquat/iron toxicity: Implications for autosomic recessive juvenile parkinsonism.

PubMed

Ortega-Arellano, Hector Flavio; Jimenez-Del-Rio, Marlene; Velez-Pardo, Carlos

2017-05-01

Autosomal recessive Juvenile Parkinsonism (AR-JP) is a chronic, progressive neurodegenerative disorder caused by mutation in the PARKIN gene, and invariably associated with dopaminergic (DAergic) neuronal loss and brain iron accumulation. Since current medical therapy is symptomatic and lacks significant disease-modifying effects, other treatment approaches are urgently needed it. In the present work, we investigate the role of minocycline (MC) in paraquat (PQ)/iron-induced neurotoxicity in the Drosophila TH>parkin-RNAi/+ (w[*]; UAS-parkin-RNAi; TH-GAL4) fly and have shown the following: (i) MC increased life span and restored the locomotor activity of knockdown (KD) transgenic parkin flies in comparison with the control (vehicle) group; (ii) MC at low (0.1 and 0.3mM) and middle (0.5mM) concentrations protected, rescued and prevented KD parkin Drosophila against PQ toxicity. However, MC at high (1mM) concentration aggravated the toxic effect of PQ; (iii) MC protected and rescued DAergic neurons against the PQ toxic effect according to tyrosine hydroxylase (TH)>green-fluorescent protein (GFP) reporter protein microscopy and anti-TH Western blotting analysis; (iv) MC protected DAergic neurons against PQ/iron toxicity; (v) MC significantly abridged lipid peroxidation (LPO) in the protection, rescue and prevention treatment in TH>parkin-RNAi/+ flies against PQ or iron alone or combined (PQ/iron)-induced neuronal oxidative stress (OS). Our results suggest that MC exerts neuroprotection against PQ/iron-induced OS in DAergic neurons most probably by the scavenging activity of reactive oxygen species (ROS), and by chelating iron. Therefore, MC might be a potential therapeutic drug to delay, revert, or prevent AR-JP. Copyright © 2017 Elsevier B.V. All rights reserved.

Vulnerable Parkin Loss-of-Function Drosophila Dopaminergic Neurons Have Advanced Mitochondrial Aging, Mitochondrial Network Loss and Transiently Reduced Autophagosome Recruitment.

PubMed

Cackovic, Juliana; Gutierrez-Luke, Susana; Call, Gerald B; Juba, Amber; O'Brien, Stephanie; Jun, Charles H; Buhlman, Lori M

2018-01-01

Selective degeneration of substantia nigra dopaminergic (DA) neurons is a hallmark pathology of familial Parkinson's disease (PD). While the mechanism of degeneration is elusive, abnormalities in mitochondrial function and turnover are strongly implicated. An Autosomal Recessive-Juvenile Parkinsonism (AR-JP) Drosophila melanogaster model exhibits DA neurodegeneration as well as aberrant mitochondrial dynamics and function. Disruptions in mitophagy have been observed in parkin loss-of-function models, and changes in mitochondrial respiration have been reported in patient fibroblasts. Whether loss of parkin causes selective DA neurodegeneration in vivo as a result of lost or decreased mitophagy is unknown. This study employs the use of fluorescent constructs expressed in Drosophila DA neurons that are functionally homologous to those of the mammalian substantia nigra. We provide evidence that degenerating DA neurons in parkin loss-of-function mutant flies have advanced mitochondrial aging, and that mitochondrial networks are fragmented and contain swollen organelles. We also found that mitophagy initiation is decreased in park ( Drosophila parkin/PARK2 ortholog) homozygous mutants, but autophagosome formation is unaffected, and mitochondrial network volumes are decreased. As the fly ages, autophagosome recruitment becomes similar to control, while mitochondria continue to show signs of damage, and climbing deficits persist. Interestingly, aberrant mitochondrial morphology, aging and mitophagy initiation were not observed in DA neurons that do not degenerate. Our results suggest that parkin is important for mitochondrial homeostasis in vulnerable Drosophila DA neurons, and that loss of parkin-mediated mitophagy may play a role in degeneration of relevant DA neurons or motor deficits in this model.

PGAM5 regulates PINK1/Parkin-mediated mitophagy via DRP1 in CCCP-induced mitochondrial dysfunction.

PubMed

Park, Yun Sun; Choi, Su Eun; Koh, Hyun Chul

2018-03-01

Mitochondrial dynamics and mitophagy are critical processes for regulating mitochondrial homeostasis. Phosphoglycerate mutase family member 5 (PGAM5) is a mitochondrial protein that plays crucial roles in apoptosis and necroptosis, but the roles of PGAM5 in mitochondrial dynamics and mitophagy remain unclear. In this study, we investigated the role of PGAM5 in carbonyl cyanide m-chlorophenylhydrazone (CCCP)-induced mitochondrial damage and the correlation between mitochondrial dynamics and mitophagy using SH-SY5Y cells. We found that CCCP decreased mitochondrial membrane potential, resulting in mitochondrial dysfunction. CCCP increased PGAM5, dynamin-related protein 1 (DRP1), and optic atrophy 1 (OPA1) expression of the mitochondrial fraction in a time-dependent manner. Knockdown of PGAM5 inhibited DRP1 translocation without a change in OPA1 expression in CCCP-treated cells. Furthermore, knockdown of PGAM5 and DRP1 significantly blocked the increase of PTEN-induced putative protein kinase 1 (PINK1) and Parkin expression in the mitochondrial fraction of CCCP-treated cells. Interestingly, CCCP did not alter PINK1/Parkin expression in the mitochondrial fraction of OPA1 knockdown cells. Inhibiting mitophagy by PGAM5 knockdown accelerated CCCP-induced apoptosis. CCCP treatment also results in PINK1 stabilization on the mitochondrial membrane, which subsequently increases Parkin recruitment from the cytosol to abnormal mitochondria. In addition, we found that CCCP increased the level of mitochondrial LC3II, indicating that Parkin recruitment of PINK1 is a result of mitophagy. We propose that activation of PGAM5 is associated with DRP1 recruitment and PINK1 stabilization, which contribute to the modulation of mitophagy in CCCP-treated cells with mitochondrial dysfunction. In conclusion, we demonstrated that PGAM5 regulates PINK1-Parkin-mediated mitophagy, which can exert a neuroprotective effect against CCCP-induced apoptosis. Copyright © 2017 Elsevier B.V. All rights

Frataxin-Mediated PINK1-Parkin-Dependent Mitophagy in Hepatic Steatosis: The Protective Effects of Quercetin.

PubMed

Liu, Peiyi; Lin, Hongkun; Xu, Yanyan; Zhou, Feng; Wang, Jing; Liu, Jingjing; Zhu, Xinhong; Guo, Xiaoping; Tang, Yuhan; Yao, Ping

2018-06-23

Naturally occurring quercetin has been found to induce mitophagy and prevent non-alcoholic fatty liver disease (NAFLD). However, it still remains elusive whether frataxin upregulation by quercetin contributes to the beneficial effect through mitophagy or not. Adult male C57BL/J mice were fed a high fat diet (HFD, 60% of energy from fat) with quercetin (100 mg/kg.bw) or not for 10 weeks. Quercetin alleviated HFD-induced histopathological changes, disorders of lipid metabolism, mitochondrial damage. Moreover, quercetin blocked mitophagy suppression by HFD based on the increased LC3II, PINK1 and Beclin1 expressions, as well as decreased p62 levels. Quercetin also improved the Parkin translocation to mitochondria confirmed by immunofluorescence. Specifically, frataxin was lowered in the liver of HFD-fed mice or HepG2 cell incubated with oleate/palmitate but restored by quercetin. And quercetin's regulation of frataxin may depend on p53. Furthermore, lentivirus-mediated stable knockdown of frataxin in HepG2 inhibited PINK1- Parkin-associated mitophagy and resulted in lipid accumulation. Frataxin was further decreased by free fatty acids in knockdown cells concomitantly with depressed PINK1-Parkin-associated mitophagy, which was partially normalized by quercetin. Quercetin alleviated hepatic steatosis by enhancing frataxin-mediated PINK1/Parkin-dependent mitophagy, highlighting a promising preventive strategy and mechanism for NAFLD by quercetin. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Carnosic acid protects SH-SY5Y cells against 6-hydroxydopamine-induced cell death through upregulation of parkin pathway.

PubMed

Lin, Chia-Yuan; Tsai, Chia-Wen; Tsai, Chia-Wen

2016-11-01

Parkin is a Parkinson's disease (PD)-linked gene that plays an important role in the ubiquitin-proteasome system (UPS). This study explored whether carnosic acid (CA) from rosemary protects against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity via upregulation of parkin in vivo and in vitro. We found that the reduction in proteasomal activity by 6-OHDA was attenuated in SH-SY5Y cells pretreated with 1 μM CA. Immunoblots showed that CA reversed the induction of ubiquitinated protein and the reduction of PTEN-induced putative kinase 1 (PINK1) and parkin protein in 6-OHDA-treated SH-SY5Y cells and rats. Moreover, in a transgenic OW13 Caenorhabditis elegans model of PD that expresses human α-synuclein in muscle cells, CA reduced α-synuclein accumulation in a dose-dependent manner. In cells pretreated with the proteasome inhibitor MG132, CA no longer reversed the 6-OHDA-mediated induction of cleavage of caspase 3 and poly(ADP)-ribose polymerase and no longer reversed the suppression of proteasome activity. When parkin expression was silenced by use of small interfering RNA, the ability of CA to inhibit apoptosis and induce proteasomal activity was significantly reduced. The reduction in 6-OHDA-induced neurotoxicity by CA was associated with the induction of parkin, which in turn upregulated the UPS and then decreased cell death. Copyright © 2016. Published by Elsevier Ltd.

Mfn2 ubiquitination by PINK1/parkin gates the p97-dependent release of ER from mitochondria to drive mitophagy

PubMed Central

McLelland, Gian-Luca; Goiran, Thomas; Yi, Wei; Dorval, Geneviève; Chen, Carol X; Lauinger, Nadine D; Krahn, Andrea I; Valimehr, Sepideh; Rakovic, Aleksandar; Rouiller, Isabelle; Durcan, Thomas M; Trempe, Jean-François

2018-01-01

Despite their importance as signaling hubs, the function of mitochondria-ER contact sites in mitochondrial quality control pathways remains unexplored. Here we describe a mechanism by which Mfn2, a mitochondria-ER tether, gates the autophagic turnover of mitochondria by PINK1 and parkin. Mitochondria-ER appositions are destroyed during mitophagy, and reducing mitochondria-ER contacts increases the rate of mitochondrial degradation. Mechanistically, parkin/PINK1 catalyze a rapid burst of Mfn2 phosphoubiquitination to trigger p97-dependent disassembly of Mfn2 complexes from the outer mitochondrial membrane, dissociating mitochondria from the ER. We additionally demonstrate that a major portion of the facilitatory effect of p97 on mitophagy is epistatic to Mfn2 and promotes the availability of other parkin substrates such as VDAC1. Finally, we reconstitute the action of these factors on Mfn2 and VDAC1 ubiquitination in a cell-free assay. We show that mitochondria-ER tethering suppresses mitophagy and describe a parkin-/PINK1-dependent mechanism that regulates the destruction of mitochondria-ER contact sites. PMID:29676259

Neonatal C57BL/6J and parkin mice respond differently following developmental manganese exposure: Result of a high dose pilot study.

PubMed

Foster, Melanie L; Bartnikas, Thomas B; Maresca-Fichter, Hailey C; Mercadante, Courtney; Dash, Miriam; Miller, Chelsea; Dorman, David C

2018-01-01

It has been suggested that childhood exposure to neurotoxicants may increase the risk of Parkinson's disease (PD) or other neurodegenerative disease in adults. Some recessive forms of PD have been linked to loss-of-function mutations in the Park2 gene that encodes for parkin. The purpose of this pilot study was to evaluate whether responses to neonatal manganese (Mn) exposure differ in mice with a Park2 gene defect (parkin mice) when compared with a wildtype strain (C57BL/6J). Neonatal parkin and C57BL/6J littermates were randomly assigned to 0, 11, or 25mg Mn/kg-day dose groups with oral exposures occurring from postnatal day (PND) 1 through PND 28. Motor activity was measured on PND 19-22 and 29-32. Tissue Mn concentrations were measured in liver, femur, olfactory bulb, frontal cortex, and striatum on PND 29. Hepatic and frontal cortex gene expression of Slc11a2, Slc40a1, Slc30a10, Hamp (liver only), and Park2 were also measured on PND 29. Some strain differences were seen. As expected, decreased hepatic and frontal cortex Park2 expression was seen in the parkin mice when compared with C57BL/6J mice. Untreated parkin mice also had higher liver and femur Mn concentrations when compared with the C57BL/6J mice. Exposure to≥11mg Mn/kg-day was associated with increased brain Mn concentrations in all mice, no strain difference was observed. Manganese exposure in C57Bl6, but not parkin mice, was associated with a negative correlation between striatal Mn concentration and motor activity. Manganese exposure was not associated with changes in frontal cortex gene expression. Decreased hepatic Slc30a10, Slc40a1, and Hamp expression were seen in PND 29 C57BL/6J mice given 25mg Mn/kg-day. In contrast, Mn exposure was only associated with decreased Hamp expression in the parkin mice. Our results suggest that the Parkin gene defect did not increase the susceptibility of neonatal mice to adverse health effects associated with high-dose Mn exposure. Copyright © 2017 Elsevier B

Albumin Overload and PINK1/Parkin Signaling-Related Mitophagy in Renal Tubular Epithelial Cells.

PubMed

Tan, Jin; Xie, Qi; Song, Shuling; Miao, Yuyang; Zhang, Qiang

2018-03-01

BACKGROUND Albumin, as a major urinary protein component, is a risk factor for chronic kidney disease progression. Mitochondrial dysfunction is one of the main causes of albumin-induced proximal tubule cells injury. Mitophagy is considered as a pivotal protective mechanism for the elimination of dysfunctional mitochondria. The objective of this research was to determine whether albumin overload-induced mitochondrial dysfunction can activate PINK1/Parkin-mediated mitophagy in renal tubular epithelial cells (TECs). MATERIAL AND METHODS Immunofluorescence assay and Western blot assay were used to detect the effects of albumin overload on autophagy marker protein LC3. Transmission electron microscopy and Western blot assay were used to investigate the role of albumin in mitochondrial injury. Western blot assay and co-localization of acidic lysosomes and mitochondria assay were employed to detect the activation of mitophagy induced by albumin. Finally, we explored the role of PINK1/Parkin signaling in albumin-induced mitophagy by inhibiting mitophagy by knockdown of PARK2 (Parkin) level. RESULTS Immunofluorescence and Western blot results showed that the expression level of LC3-II increased, and the maximum increase point was observed after 8 h of albumin treatment. Transmission electron microscopy results demonstrated that albumin overload-induced mitochondrial injury and quantity of autophagosomes increased. Additionally, expression of PINK1 and cytosolic cytochrome C increased and mitochondria cytochrome C decreased in the albumin group. The co-localization of acidic lysosomes and mitochondria demonstrated that the number of albumin overload-induced mitophagy-positive dots increased. The transient transfection of PARK2 siRNA result showed knockdown of the expression level of PARK2 can inhibit mitophagy induced by albumin. CONCLUSIONS In conclusion, our study suggests that mitochondrial dysfunction activates the PINK1/Parkin signaling and mitophagy in renal tubular

Precise identification of endogenous proviruses of NFS/N mice participating in recombination with moloney ecotropic murine leukemia virus (MuLV) to generate polytropic MuLVs.

PubMed

Alamgir, A S M; Owens, Nick; Lavignon, Marc; Malik, Frank; Evans, Leonard H

2005-04-01

Polytropic murine leukemia viruses (MuLVs) are generated by recombination of ecotropic MuLVs with env genes of a family of endogenous proviruses in mice, resulting in viruses with an expanded host range and greater virulence. Inbred mouse strains contain numerous endogenous proviruses that are potential donors of the env gene sequences of polytropic MuLVs; however, the precise identification of those proviruses that participate in recombination has been elusive. Three different structural groups of proviruses in NFS/N mice have been described and different ecotropic MuLVs preferentially recombine with different groups of proviruses. In contrast to other ecotropic MuLVs such as Friend MuLV or Akv that recombine predominantly with a single group of proviruses, Moloney MuLV (M-MuLV) recombines with at least two distinct groups. In this study, we determined that only three endogenous proviruses, two of one group and one of another group, are major participants in recombination with M-MuLV. Furthermore, the distinction between the polytropic MuLVs generated by M-MuLV and other ecotropic MuLVs is the result of recombination with a single endogenous provirus. This provirus exhibits a frameshift mutation in the 3' region of the surface glycoprotein-encoding sequences that is excluded in recombinants with M-MuLV. The sites of recombination between the env genes of M-MuLV and endogenous proviruses were confined to a short region exhibiting maximum homology between the ecotropic and polytropic env sequences and maximum stability of predicted RNA secondary structure. These observations suggest a possible mechanism for the specificity of recombination observed for different ecotropic MuLVs.

Involvement of Parkin in the ubiquitin proteasome system-mediated degradation of N-type voltage-gated Ca2+ channels.

PubMed

Grimaldo, Lizbeth; Sandoval, Alejandro; Garza-López, Edgar; Felix, Ricardo

2017-01-01

N-type calcium (CaV2.2) channels are widely expressed in the brain and the peripheral nervous system, where they play important roles in the regulation of transmitter release. Although CaV2.2 channel expression levels are precisely regulated, presently little is known regarding the molecules that mediate its synthesis and degradation. Previously, by using a combination of biochemical and functional analyses, we showed that the complex formed by the light chain 1 of the microtubule-associated protein 1B (LC1-MAP1B) and the ubiquitin-proteasome system (UPS) E2 enzyme UBE2L3, may interact with the CaV2.2 channels promoting ubiquitin-mediated degradation. The present report aims to gain further insights into the possible mechanism of degradation of the neuronal CaV2.2 channel by the UPS. First, we identified the enzymes UBE3A and Parkin, members of the UPS E3 ubiquitin ligase family, as novel CaV2.2 channel binding partners, although evidence to support a direct protein-protein interaction is not yet available. Immunoprecipitation assays confirmed the interaction between UBE3A and Parkin with CaV2.2 channels heterologously expressed in HEK-293 cells and in neural tissues. Parkin, but not UBE3A, overexpression led to a reduced CaV2.2 protein level and decreased current density. Electrophysiological recordings performed in the presence of MG132 prevented the actions of Parkin suggesting enhanced channel proteasomal degradation. Together these results unveil a novel functional coupling between Parkin and the CaV2.2 channels and provide a novel insight into the basic mechanisms of CaV channels protein quality control and functional expression.

Modulation of ARTS and XIAP by Parkin Is Associated with Carnosic Acid Protects SH-SY5Y Cells against 6-Hydroxydopamine-Induced Apoptosis.

PubMed

Fu, Ru-Huei; Huang, Li-Chun; Lin, Chia-Yuan; Tsai, Chia-Wen

2018-02-01

The mediation of apoptosis-related protein in the TGF-β signaling pathway (ARTS) and X-liked inhibitor of apoptosis protein (XIAP) by parkin plays a critical role in preventing Parkinson's disease. We studied whether carnosic acid (CA) could prevent 6-hydroxydopamine (6-OHDA)-induced apoptosis by modulating ARTS and XIAP through parkin in SH-SY5Y cells. In cells treated with 6-OHDA, the protein expression of ARTS is increased and XIAP is decreased. Pretreatment of cells with CA reversed these effects. Moreover, CA attenuated the activation of caspase 9 and caspase 7 by 6-OHDA. By immunoprecipitation with ARTS antibody, we found that 6-OHDA increased the protein expression of XIAP. However, pretreatment of cells with CA reduced XIAP protein and increased the ubiquitination of ARTS. Silencing of parkin attenuated the ability of CA to reverse the induction of ARTS and apoptotic-related proteins and the reduction of XIAP and parkin protein by 6-OHDA. Similarly, reversal of 6-OHDA-induced nuclear condensation and apoptotic-related proteins by CA was inhibited in cells with XIAP silencing. In conclusion, CA induces parkin by enhancing the ubiquitination of ARTS, leading to induction of XIAP. This may be a novel strategy for preventing Parkinson's disease.

Sorafenib targets the mitochondrial electron transport chain complexes and ATP synthase to activate the PINK1-Parkin pathway and modulate cellular drug response.

PubMed

Zhang, Conggang; Liu, Zeyu; Bunker, Eric; Ramirez, Adrian; Lee, Schuyler; Peng, Yinghua; Tan, Aik-Choon; Eckhardt, S Gail; Chapnick, Douglas A; Liu, Xuedong

2017-09-08

Sorafenib (Nexavar) is a broad-spectrum multikinase inhibitor that proves effective in treating advanced renal-cell carcinoma and liver cancer. Despite its well-characterized mechanism of action on several established cancer-related protein kinases, sorafenib causes variable responses among human tumors, although the cause for this variation is unknown. In an unbiased screening of an oncology drug library, we found that sorafenib activates recruitment of the ubiquitin E3 ligase Parkin to damaged mitochondria. We show that sorafenib inhibits the activity of both complex II/III of the electron transport chain and ATP synthase. Dual inhibition of these complexes, but not inhibition of each individual complex, stabilizes the serine-threonine protein kinase PINK1 on the mitochondrial outer membrane and activates Parkin. Unlike the protonophore carbonyl cyanide m -chlorophenylhydrazone, which activates the mitophagy response, sorafenib treatment triggers PINK1/Parkin-dependent cellular apoptosis, which is attenuated upon Bcl-2 overexpression. In summary, our results reveal a new mechanism of action for sorafenib as a mitocan and suggest that high Parkin activity levels could make tumor cells more sensitive to sorafenib's actions, providing one possible explanation why Parkin may be a tumor suppressor gene. These insights could be useful in developing new rationally designed combination therapies with sorafenib. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Prevention of 3-methylcholanthrene-induced fibrosarcomas in rats pre-inoculated with endogenous rat retrovirus

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

Fish, D.C.; Demarais, J.T.; Djurickovic, D.B.

1981-04-01

Weanling Fischer 344 rats received a single intraperitoneal injection of a 1000-fold concentrated preparation of endogenous nontransforming rat retrovirus. Ten days later, the rats were each given a single subcutaneous injection of 3-methylcholanthrene. The rats inoculated with the endogenous rat retrovirus were significantly protected against the development of cancer, whereas uninoculated rats and rats given one of several murine tetroviruses or baboon retrovirus were not protected.

Carnosic Acid Attenuates 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells by Inducing Autophagy Through an Enhanced Interaction of Parkin and Beclin1.

PubMed

Lin, Chia-Yuan; Tsai, Chia-Wen

2017-05-01

Enhanced removal of abnormal protein aggregates or injured organelles through autophagy is related to neuroprotection in Parkinson's disease. In this study, we explored whether the induction of autophagy is associated with the neuroprotection of rosemary carnosic acid (CA) against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in SH-SY5Y cells. The results indicated that cells treated with CA had increased protein levels of parkin and autophagy-related markers, including phosphatidylinositol 3-kinase p100, Beclin1, autophagy-related gene 7, and microtubule-associated protein 1 light chain 3-II, as well as enhanced formation of autophagic vacuoles. Treatment of cells with 6-OHDA decreased the levels of parkin and the autophagy markers, but CA pretreatment reversed these effects. However, wortmannin (an autophagosome formation blocker) pretreatment attenuated the effect of CA. After CA pretreatment, the induction of cleaved caspase 3, cleaved poly-ADP ribose polymerase, and nuclear condensation by 6-OHDA were alleviated. Both wortmannin and bafilomycin A1 (an autophagosome-lysosome fusion blocker) inhibited the anti-apoptosis effects of CA. Additionally, we performed immunoprecipitation with anti-parkin antibody and found that the interaction of parkin and Beclin1 protein was reduced by 6-OHDA but that this effect was reversed in cells pretreated with CA. Moreover, transfection of parkin siRNA in cells inhibited the ability of CA to alleviate 6-OHDA-decreased autophagy-related markers and nuclear condensation. In conclusion, CA protects against 6-OHDA-induced apoptosis by inducing autophagy through the interaction of parkin and Beclin1. These results provide a future strategy for use of CA in the prevention of Parkinson's disease.

Relative high frequency of the c.255delA parkin gene mutation in Spanish patients with autosomal recessive parkinsonism

PubMed Central

Munoz, E; Tolosa, E; Pastor, P; Marti, M; Valldeoriola, F; Campdelacreu, J; Oliva, R

2002-01-01

Objectives: To search for the presence of parkin gene mutations in Spanish patients with Parkinson's disease (PD) and characterise the phenotype associated with these mutations. Methods: Thirty seven PD patients with either early onset or autosomal recessive pattern of inheritance were selected for genetic study. Results: Mutations were identified in seven index patients (19%). Homozygous mutations were detected in six patients and a heterozygous mutation in one. The age at onset was lower in patients with mutations than in patients without mutations. Dystonia at onset was present in two patients with parkin gene mutations. The disease began in two patients with postural tremor in the upper limbs mimicking essential tremor. Four patients exhibited a long term response to dopamine agonists. The c.255delA mutation was identified in four unrelated families. This is a frameshift mutation leading to protein truncation. Conclusions: Parkin gene mutations are present in Spanish patients with early onset and/or an autosomal recessive parkinsonism. The c.255delA is the most frequent mutation found, suggesting a relative high prevalence in the Spanish population. PMID:12397156

Role of endogenous insulin gene enhancer protein ISL-1 in angiogenesis

PubMed Central

Xiong, Si-qi; Jiang, Hai-bo; Li, Yan-xiu; Li, Hai-bo; Xu, Hui-zhuo; Wu, Zhen-kai; Zheng, Wei

2016-01-01

Objective To elucidate the role of insulin gene enhancer protein ISL-1 (Islet-1) in angiogenesis and regulation of vascular endothelial growth factor (VEGF) expression in vitro and in vivo. Methods siRNA targeting Islet-1 was transfected to human umbilical vein endothelial cell lines (HUVECs). The expression of Islet-1 and VEGF in the cultured cells was measured using real-time PCR and immunoblotting. 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide; thiazolyl blue (MTT) assay was used to analyze the proliferation of HUVECs affected by Islet-1. Wound healing and Transwell assays were conducted to assess the motility of HUVECs. The formation of capillary-like structures was examined using growth factor–reduced Matrigel. siRNA targeting Islet-1 was intravitreally injected into the murine model of oxygen-induced retinopathy (OIR). Retinal neovascularization was evaluated with angiography using fluorescein-labeled dextran and then quantified histologically. Real-time PCR and immunoblotting were used to determine whether local Islet-1 silencing affected the expression of Islet-1 and VEGF in murine retinas. Results The expression of Islet-1 and VEGF in HUVECs was knocked down by siRNA. Reduced endogenous Islet-1 levels in cultured cells greatly inhibited the proliferation, migration, and tube formation in HUVECs in vitro. Retinal neovascularization following injection of Islet-1 siRNA was significantly reduced compared with that of the contralateral control eye. Histological analysis indicated that the neovascular nuclei protruding into the vitreous cavity were decreased. Furthermore, the Islet-1 and VEGF expression levels were downregulated in murine retinas treated with siRNA against Islet-1. Conclusions Reducing the expression of endogenous Islet-1 inhibits proliferation, migration, and tube formation in vascular endothelial cells in vitro and suppresses retinal angiogenesis in vivo. Endogenous Islet-1 regulates angiogenesis via VEGF. PMID:27994436

PINK1/Parkin-Dependent Mitochondrial Surveillance: From Pleiotropy to Parkinson's Disease

PubMed Central

Mouton-Liger, Francois; Jacoupy, Maxime; Corvol, Jean-Christophe; Corti, Olga

2017-01-01

Parkinson's disease (PD) is one of the most frequent neurodegenerative disease caused by the preferential, progressive degeneration of the dopaminergic (DA) neurons of the substantia nigra (SN) pars compacta. PD is characterized by a multifaceted pathological process involving protein misfolding, mitochondrial dysfunction, neuroinflammation and metabolism deregulation. The molecular mechanisms governing the complex interplay between the different facets of this process are still unknown. PARK2/Parkin and PARK6/PINK1, two genes responsible for familial forms of PD, act as a ubiquitous core signaling pathway, coupling mitochondrial stress to mitochondrial surveillance, by regulating mitochondrial dynamics, the removal of damaged mitochondrial components by mitochondria-derived vesicles, mitophagy, and mitochondrial biogenesis. Over the last decade, PINK1/Parkin-dependent mitochondrial quality control emerged as a pleiotropic regulatory pathway. Loss of its function impinges on a number of physiological processes suspected to contribute to PD pathogenesis. Its role in the regulation of innate immunity and inflammatory processes stands out, providing compelling support to the contribution of non-cell-autonomous immune mechanisms in PD. In this review, we illustrate the central role of this multifunctional pathway at the crossroads between mitochondrial stress, neuroinflammation and metabolism. We discuss how its dysfunction may contribute to PD pathogenesis and pinpoint major unresolved questions in the field. PMID:28507507

Transcriptional alterations in skin fibroblasts from Parkinson's disease patients with parkin mutations.

PubMed

González-Casacuberta, Ingrid; Morén, Constanza; Juárez-Flores, Diana-Luz; Esteve-Codina, Anna; Sierra, Cristina; Catalán-García, Marc; Guitart-Mampel, Mariona; Tobías, Ester; Milisenda, José César; Pont-Sunyer, Claustre; Martí, María José; Cardellach, Francesc; Tolosa, Eduard; Artuch, Rafael; Ezquerra, Mario; Fernández-Santiago, Rubén; Garrabou, Glòria

2018-05-01

Mutations in the parkin gene (PRKN) are the most common cause of autosomal-recessive juvenile Parkinson's disease (PD). PRKN encodes an E3 ubiquitin ligase that is involved in multiple regulatory functions including proteasomal-mediated protein turnover, mitochondrial function, mitophagy, and cell survival. However, the precise molecular events mediated by PRKN mutations in PRKN-associated PD (PRKN-PD) remain unknown. To elucidate the cellular impact of parkin mutations, we performed an RNA sequencing study in skin fibroblasts from PRKN-PD patients carrying different PRKN mutations (n = 4) and genetically unrelated healthy subjects (n = 4). We identified 343 differentially expressed genes in PRKN-PD fibroblasts. Gene ontology and canonical pathway analysis revealed enrichment of differentially expressed genes in processes such as cell adhesion, cell growth, and amino acid and folate metabolism among others. Our findings indicate that PRKN mutations are associated with large global gene expression changes as observed in fibroblasts from PRKN-PD patients and support the view of PD as a systemic disease affecting also non-neural peripheral tissues such as the skin. Copyright © 2018 Elsevier Inc. All rights reserved.

Elimination of endogenous aberrant kappa chain transcripts from sp2/0-derived hybridoma cells by specific ribozyme cleavage: utility in genetic therapy of HIV-1 infections.

PubMed Central

Duan, L; Pomerantz, R J

1994-01-01

The pooled degenerate-primer polymerase chain reaction (PCR) technology is now widely used in the amplification and cloning of murine hybridoma-specific immunoglobulin gene cDNAs. The design of primers is mainly based on the highly conserved 5' terminus of immunoglobulin gene variable regions and the constant region in the 3' terminus. Of note, most murine hybridoma cell lines are derived from the Sp2/0 cell line, which is demonstrated to express endogenous aberrant kappa chains (abV kappa). This high-level endogenous abV kappa mixes with specific kappa chains in the hybridomas and interferes with the efficiency of the reverse transcriptase (RT)-PCR cloning strategy. In this report, during the cloning of murine anti-human immunodeficiency virus type I (HIV-1) hybridoma immunoglobulin cDNAs, a specific primer-PCR screening system was developed, based on the abV kappa complementarity-defining region (CDR), to eliminate abV kappa-carrying plasmids. Furthermore, an abV kappa sequence-specific derived ribozyme was developed and packaged in a retroviral expression vector system. This abV kappa ribozyme can be transduced into different murine hybridomas, and expressed intracellularly to potently eliminate endogenous abV kappa RNA. Images PMID:7816635

Mitochondrial Quality Control via the PGC1α-TFEB Signaling Pathway Is Compromised by Parkin Q311X Mutation But Independently Restored by Rapamycin.

PubMed

Siddiqui, Almas; Bhaumik, Dipa; Chinta, Shankar J; Rane, Anand; Rajagopalan, Subramanian; Lieu, Christopher A; Lithgow, Gordon J; Andersen, Julie K

2015-09-16

Following its activation by PINK1, parkin is recruited to depolarized mitochondria where it ubiquitinates outer mitochondrial membrane proteins, initiating lysosomal-mediated degradation of these organelles. Mutations in the gene encoding parkin, PARK2, result in both familial and sporadic forms of Parkinson's disease (PD) in conjunction with reductions in removal of damaged mitochondria. In contrast to what has been reported for other PARK2 mutations, expression of the Q311X mutation in vivo in mice appears to involve a downstream step in the autophagic pathway at the level of lysosomal function. This coincides with increased PARIS expression and reduced expression of a reciprocal signaling pathway involving the master mitochondrial regulator peroxisome proliferator-activated receptor-gamma coactivator (PGC1α) and the lysosomal regulator transcription factor EB (TFEB). Treatment with rapamycin was found to independently restore PGC1α-TFEB signaling in a manner not requiring parkin activity and to abrogate impairment of mitochondrial quality control and neurodegenerative features associated with this in vivo model. Losses in PGC1α-TFEB signaling in cultured rat DAergic cells expressing the Q311X mutation associated with reduced mitochondrial function and cell viability were found to be PARIS-dependent and to be independently restored by rapamycin in a manner requiring TFEB. Studies in human iPSC-derived neurons demonstrate that TFEB induction can restore mitochondrial function and cell viability in a mitochondrially compromised human cell model. Based on these data, we propose that the parkin Q311X mutation impacts on mitochondrial quality control via PARIS-mediated regulation of PGC1α-TFEB signaling and that this can be independently restored via upregulation of TFEB function. Mutations in PARK2 are generally associated with loss in ability to interact with PINK1, impacting on autophagic initiation. Our data suggest that, in the case of at least one parkin

Parkin deficiency modulates NLRP3 inflammasome activation by attenuating an A20-dependent negative feedback loop.

PubMed

Mouton-Liger, François; Rosazza, Thibault; Sepulveda-Diaz, Julia; Ieang, Amélie; Hassoun, Sidi-Mohamed; Claire, Emilie; Mangone, Graziella; Brice, Alexis; Michel, Patrick P; Corvol, Jean-Christophe; Corti, Olga

2018-04-17

Neuroinflammation and mitochondrial dysfunction, key mechanisms in the pathogenesis of Parkinson's disease (PD), are usually explored independently. Loss-of-function mutations of PARK2 and PARK6, encoding the E3 ubiquitin protein ligase Parkin and the mitochondrial serine/threonine kinase PINK1, account for a large proportion of cases of autosomal recessive early-onset PD. PINK1 and Parkin regulate mitochondrial quality control and have been linked to the modulation of innate immunity pathways. We report here an exacerbation of NLRP3 inflammasome activation by specific inducers in microglia and bone marrow-derived macrophages from Park2 -/- and Pink1 -/- mice. The caspase 1-dependent release of IL-1β and IL-18 was, therefore, enhanced in Park2 -/- and Pink1 -/- cells. This defect was confirmed in blood-derived macrophages from patients with PARK2 mutations and was reversed by MCC950, which specifically inhibits NLRP3 inflammasome complex formation. Enhanced NLRP3 signaling in Parkin-deficient cells was accompanied by a lack of induction of A20, a well-known negative regulator of the NF-κB pathway recently shown to attenuate NLRP3 inflammasome activity. We also found an inverse correlation between A20 abundance and IL-1β release, in human macrophages challenged with NLRP3 inflammasome inducers. Overall, our observations suggest that the A20/NLRP3-inflammasome axis participates in the pathogenesis of PARK2-linked PD, paving the way for the exploration of its potential as a biomarker and treatment target. © 2018 The Authors. Glia Published by Wiley Periodicals, Inc.

Evidence that the modulation of membrane-associated protein kinase C activity by an endogenous inhibitor plays a role in N1E-115 murine neuroblastoma cell differentiation.

PubMed

Chakravarthy, B R; Wong, J; Durkin, J P

1995-10-01

Murine neuroblastoma cells, N1E-115, were induced to differentiate into neuron-like cells by serum deprivation for 18 h. As previous studies have shown that the suppression of protein kinase C (PKC) activity by selective inhibitors or neutralizing antibodies induces neuroblastoma cells to differentiate, we tested the hypothesis that serum deprivation may cause a rapid loss in membrane PKC activity that occurs well before the morphological changes that are characteristic of cell differentiation. A significant reduction in particulate (membrane) PKC activity was indeed observed within 3 h of serum withdrawal when enzyme activity was measured in intact native membranes by the recently described in vitro "direct" assay. This rapid reduction in enzyme activity was confirmed by the decreased phosphorylation of the MARCKS protein, an endogenous PKC-selective substrate, in intact cells. The decrease in membrane PKC activity occurred without any loss in the amount of membrane-associated enzyme, suggesting that some factor(s) resident in neuroblastoma membranes was suppressing PKC activity. Indeed, results indicate the presence of an endogenous inhibitor of PKC tightly associated with neuroblastoma membranes. This inhibitory activity increased in the membranes of cells subjected to serum deprivation, raising the possibility that it was likely responsible for the decline in membrane PKC activity in differentiating N1E-115 cells. Preliminary characterization indicated that the inhibitory activity is a protein and is localized mainly in the membrane fraction. Thus, these results demonstrate directly that endogenous inhibitor can regulate membrane-associated PKC activity in cells and thereby modulate PKC-related neuronal functions.

Endogenous pro-resolving and anti-inflammatory lipid mediators: a new pharmacologic genus

PubMed Central

Serhan, C N; Chiang, N

2008-01-01

Complete resolution of an acute inflammatory response and its return to homeostasis are essential for healthy tissues. Here, we overview ongoing efforts to characterize cellular and molecular mechanisms that govern the resolution of self-limited inflammation. Systematic temporal analyses of evolving inflammatory exudates using mediator lipidomics-informatics, proteomics, and cellular trafficking with murine resolving exudates demonstrate novel endogenous pathways of local-acting mediators that share both anti-inflammatory and pro-resolving properties. In murine systems, resolving-exudate leukocytes switch their phenotype to actively generate new families of mediators from major omega-3 fatty acids EPA and DHA termed resolvins and protectins. Recent advances on their biosynthesis and actions are reviewed with a focus on the E-series resolvins (RvE1, RvE2), D series resolvins (RvD1, RvD2) and the protectins including neuroprotectin D1/protectin D1 (NPD1/PD1) as well as their aspirin-triggered epimeric forms. Members of each new family demonstrate potent stereo-specific actions, joining the lipoxins as endogenous local signals that govern resolution and endogenous anti-inflammation mechanisms. In addition to their origins and roles in resolution biology in the immune system, recent findings indicate that these new mediator families also display potent protective actions in lung, kidney, and eye as well as enhance microbial clearance. Thus, these endogenous agonists of resolution pathways constitute a novel genus of chemical mediators that possess pro-resolving, anti-inflammatory, and antifibrotic as well as host-directed antimicrobial actions. These may be useful in the design of new therapeutics and treatments for diseases with the underlying trait of uncontrolled inflammation and redox organ stress. PMID:17965751

Lactoferrin Expression in Human and Murine Ocular Tissue.

PubMed

Rageh, Abrar A; Ferrington, Deborah A; Roehrich, Heidi; Yuan, Ching; Terluk, Marcia R; Nelson, Elizabeth F; Montezuma, Sandra R

2016-07-01

Lactoferrin (LF) is a multifunctional protein known to provide innate defense due to its antimicrobial and anti-inflammatory properties. In the eye, LF has been identified in the tears and vitreous humor. Its presence in other ocular tissues has not been determined. Our aim is to assess the presence of LF in the cornea, iris, retina and retinal pigment epithelium (RPE) of humans and mice. To test for the endogenous production of LF, reverse transcription polymerase chain reaction was performed in cultured human cells from the cornea and RPE and in murine tissues. To confirm LF localization in specific ocular tissue, immunohistochemistry was performed on flat mounts of cornea, retina and RPE in human donor eyes. The presence of LF was assessed by western blotting in human and mouse ocular tissue and human culture cells (cornea and RPE). To verify antibody specificity, purified human LF and transferrin (TF) were used on 1D and 2D western blots. LF gene expression was confirmed in the cornea and RPE cell cultures from humans, suggesting that LF is an endogenously produced protein. PCR results from mouse ocular tissue showed LF expression in cornea, iris, RPE, but not in retina. These results were also consistent with immunohistochemical localization of LF in human donor tissue. Antibody reaction for human LF was specific and western blotting showed its presence in the cornea, iris and RPE tissues. A faint reaction for the retina was observed but was likely due to contamination from other ocular tissues. Multiple commercially available antibodies for murine LF cross-reacted with TF, so no reliable results were obtained for murine western blot. LF is expressed in multiple eye tissues of humans and mice. This widespread expression and multifunctional activity of LF suggests that it may play an important role in protecting eye tissues from inflammation-associated diseases.

Pink1 and Parkin regulate Drosophila intestinal stem cell proliferation during stress and aging.

PubMed

Koehler, Christopher L; Perkins, Guy A; Ellisman, Mark H; Jones, D Leanne

2017-08-07

Intestinal stem cells (ISCs) maintain the midgut epithelium in Drosophila melanogaster Proper cellular turnover and tissue function rely on tightly regulated rates of ISC division and appropriate differentiation of daughter cells. However, aging and epithelial injury cause elevated ISC proliferation and decreased capacity for terminal differentiation of daughter enteroblasts (EBs). The mechanisms causing functional decline of stem cells with age remain elusive; however, recent findings suggest that stem cell metabolism plays an important role in the regulation of stem cell activity. Here, we investigate how alterations in mitochondrial homeostasis modulate stem cell behavior in vivo via RNA interference-mediated knockdown of factors involved in mitochondrial dynamics. ISC/EB-specific knockdown of the mitophagy-related genes Pink1 or Parkin suppresses the age-related loss of tissue homeostasis, despite dramatic changes in mitochondrial ultrastructure and mitochondrial damage in ISCs/EBs. Maintenance of tissue homeostasis upon reduction of Pink1 or Parkin appears to result from reduction of age- and stress-induced ISC proliferation, in part, through induction of ISC senescence. Our results indicate an uncoupling of cellular, tissue, and organismal aging through inhibition of ISC proliferation and provide insight into strategies used by stem cells to maintain tissue homeostasis despite severe damage to organelles. © 2017 Koehler et al.

Characterization of airway and vascular responses in murine lungs

PubMed Central

Held, Heinz-Dieter; Martin, Christian; Uhlig, Stefan

1999-01-01

We characterized the responses of murine airways and pulmonary vessels to a variety of endogenous mediators in the isolated perfused and ventilated mouse lung (IPL) and compared them with those in precision-cut lung slices. Airways: The EC50 (μM) for contractions of airways in IPL/slices was methacholine (Mch), 6.1/1.5>serotonin, 0.7/2.0>U46619 (TP-receptor agonist), 0.1/0.06>endothelin-1, 0.1/0.05. In the IPL, maximum increase in airway resistance (RL) was 0.6, 0.4, 0.8 and 11 cmH2O s ml−1, respectively. Adenosine (⩽1 mM), bombesin (⩽100 μM), histamine (⩽10 mM), LTC4 (⩽1 μM), PAF (0.25 μM) and substance P (⩽100 μM) had only weak effects (<5% of Mch) on RL. Vessels: The EC50 (μM) for vasoconstriction in the IPL was LTC4, 0.06>U46619, 0.05Murine precision-cut lung slices maintain important characteristics of the whole organ. The maximum reagibility of murine airways to endogenous mediators is serotoninmurine pulmonary vasculature is serotonin

Vaccination directed against the human endogenous retrovirus-K envelope protein inhibits tumor growth in a murine model system.

PubMed

Kraus, Benjamin; Fischer, Katrin; Büchner, Sarah M; Wels, Winfried S; Löwer, Roswitha; Sliva, Katja; Schnierle, Barbara S

2013-01-01

Human endogenous retrovirus (HERV) genomes are chromosomally integrated in all cells of an individual. They are normally transcriptionally silenced and transmitted only vertically. Enhanced expression of HERV-K accompanied by the emergence of anti-HERV-K-directed immune responses has been observed in tumor patients and HIV-infected individuals. As HERV-K is usually not expressed and immunological tolerance development is unlikely, it is an appropriate target for the development of immunotherapies. We generated a recombinant vaccinia virus (MVA-HKenv) expressing the HERV-K envelope glycoprotein (ENV), based on the modified vaccinia virus Ankara (MVA), and established an animal model to test its vaccination efficacy. Murine renal carcinoma cells (Renca) were genetically altered to express E. coli beta-galactosidase (RLZ cells) or the HERV-K ENV gene (RLZ-HKenv cells). Intravenous injection of RLZ-HKenv cells into syngenic BALB/c mice led to the formation of pulmonary metastases, which were detectable by X-gal staining. A single vaccination of tumor-bearing mice with MVA-HKenv drastically reduced the number of pulmonary RLZ-HKenv tumor nodules compared to vaccination with wild-type MVA. Prophylactic vaccination of mice with MVA-HKenv precluded the formation of RLZ-HKenv tumor nodules, whereas wild-type MVA-vaccinated animals succumbed to metastasis. Protection from tumor formation correlated with enhanced HERV-K ENV-specific killing activity of splenocytes. These data demonstrate for the first time that HERV-K ENV is a useful target for vaccine development and might offer new treatment opportunities for diverse types of cancer.

Endogenous biosynthesis of thromboxane and prostacyclin in 2 distinct murine models of atherosclerosis.

PubMed

Praticò, D; Cyrus, T; Li, H; FitzGerald, G A

2000-12-01

Thromboxane A(2) is a potent vasoconstrictor and platelet agonist; prostacyclin is a potent platelet inhibitor and vasodilator. Altered biosynthesis of these eicosanoids is a feature of human hypercholesterolemia and atherosclerosis. This study examined whether in 2 murine models of atherosclerosis their levels are increased and correlated with the evolution of the disease. Urinary 2,3-dinor thromboxane B(2) and 2,3-dinor-6-keto prostaglandin F(1 alpha), metabolites of thromboxane and prostacyclin, respectively, were assayed in apoliprotein E (apoE)-deficient mice on chow and low-density lipoprotein receptor (LDLR)-deficient mice on chow and a Western-type diet. Atherosclerosis lesion area was measured by en face method. Both eicosanoids increased in apoE-deficient mice on chow and in LDLR-deficient mice on a high-fat diet, but not in LDLR-deficient mice on chow by the end of the study. Aspirin suppressed ex vivo platelet aggregation, serum thromboxane B(2), and 2,3-dinor thromboxane B(2), and significantly reduced the excretion of 2,3-dinor-6-keto prostaglandin F(1 alpha) in these animals. This study demonstrates that thromboxane as well as prostacyclin biosynthesis is increased in 2 murine models of atherogenesis and is secondary to increased in vivo platelet activation. Assessment of their generation in these models may afford the basis for future studies on the functional role of these eicosanoids in the evolution and progression of atherosclerosis. (Blood. 2000;96:3823-3826)

Activation of endogenous antioxidants as a common therapeutic strategy against cancer, neurodegeneration and cardiovascular diseases: A lesson learnt from DJ-1.

PubMed

Chan, Julie Y H; Chan, Samuel H H

2015-12-01

This review aims at presenting a new concept pertaining to the development of antioxidants, namely, to evolve from disease-oriented therapy to mechanism-oriented therapy. Using as our illustrative example is DJ-1, a homodimeric protein that is ubiquitously expressed in a variety of mammalian tissues, including the brain, and is found in the matrix and the intermembrane space of the mitochondria. DJ-1 is known to be an endogenous antioxidant against cancer, neurodegeneration and cardiovascular diseases, of which oxidative stress plays a causal role. Interestingly, the mechanistic targets of DJ-1 as an antioxidant, including Daxx, Nrf2, thioredoxin, glutathione, α-synuclein, PTEN/PI3K/Akt, and Pink/Parkin are also associated with those oxidative stress-related diseases. Furthermore, activators of DJ-1 are available in the form of mortalin, phenylbutyrate and quinone oxidoreductase 1. It follows that activation of DJ-1 as a common endogenous antioxidant provides a new strategy against cancer, neurodegeneration and cardiovascular diseases. Since clinical trials on exogenous application of the known antioxidants have basically failed, an alternative approach would logically be to activate the endogenous antioxidants that are already present in the appropriate cellular locale where elevated oxidative stress is the culprit for the disease. At the same time, since oxidative stress is a common denominator among cancer, neurodegeneration and cardiovascular diseases, development of antioxidant therapy should target the reduction in reactive oxygen species. Instead of focusing on disease-oriented therapy, pharmaceutical companies should concentrate on developing agents and dosing schemes for effective activation of the endogenous antioxidants that are associated with a multitude of oxidative stress-related diseases (mechanism-oriented therapy). Copyright © 2015 Elsevier Inc. All rights reserved.

Dual Roles of Endogenous Platelet-activating Factor Acetylhydrolase in a Murine Model of Necrotizing Enterocolitis

PubMed Central

Lu, Jing; Pierce, Marissa; Franklin, Andrew; Jilling, Tamas; Stafforini, Diana M.; Caplan, Michael

2010-01-01

Human preterm infants with necrotizing enterocolitis (NEC) have increased circulating and luminal levels of platelet-activating factor (PAF) and decreased serum PAF-acetylhydrolase (PAF-AH), the enzyme that inactivates PAF. Formula supplemented with recombinant PAF-AH decreases NEC in a neonatal rat model. We hypothesized that endogenous PAF-AH contributes to neonatal intestinal homeostasis, and therefore developed PAF-AH−/− mice using standard approaches to study the role of this enzyme in the neonatal NEC model. Following exposure to a well-established NEC model, intestinal tissues were evaluated for histology, pro-inflammatory cytokine mRNA synthesis, and death using standard techniques. We found that mortality rates were significantly lower in PAF-AH−/− pups compared to wild-type controls before 24 hours of life but surviving PAF-AH−/− animals were more susceptible to NEC development compared to wild-type controls. Increased NEC incidence was associated with prominent inflammation characterized by elevated intestinal mRNA expression of sPLA2, iNOS and CXCL1. In conclusion, the data support a protective role for endogenous PAF-AH in the development of NEC, and since preterm neonates have endogenous PAF-AH deficiency, this may place them at increased risk for disease. PMID:20531249

iPS models of Parkin and PINK1.

PubMed

Rakovic, Aleksandar; Seibler, Philip; Klein, Christine

2015-04-01

Parkinson disease (PD) is a degenerative disorder of the central nervous system resulting from depletion of dopaminergic neurons and currently remains incurable despite enormous international research efforts. The development of induced pluripotent stem cell (iPSC) technology opened up the unique possibility of studying disease mechanisms in human tissue that was otherwise not accessible, such as the brain. Of particular interest are the monogenetic forms of PD as they closely resemble the more common 'idiopathic' PD and, through the mutated protein, provide a clear research target in iPSC-derived neurons. Recessively inherited Parkin and PTEN-induced putative kinase 1 (PINK1) mutations have been investigated in this context and the present review describes the first insights gained from studies in iPSC-derived dopaminergic neurons, which comprise abnormalities in mitochondrial and dopamine homoeostasis, microtubular stability and axonal outgrowth. These new models of PD have a high translational potential that includes the identification of druggable targets, testing of known and novel therapeutic agents in the disease-relevant tissue using well-defined read-outs and potential regenerative approaches.

In vitro and in vivo effects of CpG-Oligodeoxynucleotides (CpG-ODN) on murine transitional cell carcinoma and on the native murine urinary bladder wall.

PubMed

Olbert, Peter Jochen; Schrader, Andres Jan; Simon, Corinna; Dalpke, Alexander; Barth, Peter; Hofmann, Rainer; Hegele, Axel

2009-06-01

Intravesical BCG instillation is established and efficient in the prophylaxis of recurrent transitional cell carcinoma. A Th-1 biased immune response is postulated. Recent work has proven the efficacy of synthetic CpG-Oligodeoxynucleotides (ODN) as inducers and adjuvants for a strong Th1-response and there is evidence for a direct and/or adjuvant anti-neoplastic effect. The purpose of this study was to examine the local effects of CpG-ODN on the murine bladder wall after intravesical instillation and the effects on cytokine expression in an orthotopic murine bladder cancer model. Histopathology, immunohistochemistry and fluorescence microscopy were performed after different instillation schedules of stimulatory, non-stimulatory biotinylized and FITC-labelled CpG-ODN into the murine bladder. MB-49 murine bladder cancer cells were tested for TLR-9 expression to exclude a potential direct responsiveness to CpG-ODN. Furthermore induction of apoptosis was tested by annexin V staining and FACS analysis of CpG-ODN stimulated tumor cells. In an orthotopic C57/Bl6 murine bladder cancer model, the expressions of IL-12, IFNgamma, IL-10 and TGF-beta were evaluated after repeated CpG-ODN treatment. Single and repeated instillation of CpG-ODN induced subepithelial and urothelial lymphocytic infiltrations with consecutive apoptoses. PBS and non-stimulative ODN induced no visible reaction. Bladder submucosa stained positive for biotin. Controls showed no endogenic biotin staining. FITC-labelled ODN adhered to the bladder mucosa and penetration of the mucosal barrier was not detected. MB-49 TCC cells did not express TLR-9 and CpG-ODN did not induce apoptosis in these cells. Repeated intravesical instillations of CpG-ODN in orthotopic murine tumor bearing urinary bladders resulted in significant up-regulation of both Th-1 and Th-2 cytokines. CpG-ODNs have promising anti-neoplastic potential. They exert a pronounced immunological response both in the native murine urinary bladder and

Impaired parkin-mediated mitochondrial targeting to autophagosomes differentially contributes to tissue pathology in lysosomal storage diseases

PubMed Central

de Pablo-Latorre, Raquel; Saide, Assunta; Polishhuck, Elena V.; Nusco, Edoardo; Fraldi, Alessandro; Ballabio, Andrea

2012-01-01

Dysfunctional mitochondria are a well-known disease hallmark. The accumulation of aberrant mitochondria can alter cell homeostasis, thus resulting in tissue degeneration. Lysosomal storage disorders (LSDs) are a group of inherited diseases characterized by the buildup of undegraded material inside the lysosomes that leads to autophagic-lysosomal dysfunction. In LSDs, autophagic stress has been associated to mitochondrial accumulation and dysfunction. However, the mechanisms underlying mitochondrial aberrations and how these are involved in tissue pathogenesis remain largely unexplored. In normal conditions, mitochondrial clearance occurs by mitophagy, a selective form of autophagy, which relies on a parkin-mediated mitochondrial priming and subsequent sequestration by autophagosomes. Here, we performed a detailed analysis of key steps of mitophagy in a mouse model of multiple sulfatase deficiency (MSD), a severe type of LSD characterized by both neurological and systemic involvement. We demonstrated that in MSD liver reduced parkin levels resulted in inefficient mitochondrial priming, thus contributing to the accumulation of giant mitochondria that are located outside autophagic vesicles ultimately leading to cytochrome c release and apoptotic cell death. Morphological and functional changes were also observed in mitochondria from MSD brain but these were not directly associated with neuronal cell loss, suggesting a secondary contribution of mitochondria to neurodegeneration. Together, these data shed new light on the mechanisms underlying mitochondrial dysfunction in LSDs and on their tissue-specific differential contribution to the pathogenesis of this group of metabolic disorders. PMID:22215441

Genotype-phenotype relations for the Parkinson's Disease genes Parkin, PINK1, DJ1: MDSGene Systematic Review.

PubMed

Kasten, Meike; Hartmann, Corinna; Hampf, Jennie; Schaake, Susen; Westenberger, Ana; Vollstedt, Eva-Juliane; Balck, Alexander; Domingo, Aloysius; Vulinovic, Franca; Dulovic, Marija; Zorn, Ingo; Madoev, Harutyun; Zehnle, Hanna; Lembeck, Christina M; Schawe, Leopold; Reginold, Jennifer; Huang, Jana; König, Inke R; Bertram, Lars; Marras, Connie; Lohmann, Katja; Lill, Christina M; Klein, Christine

2018-04-11

This first comprehensive MDSGene review is devoted to the 3 autosomal recessive Parkinson's disease forms: PARK-Parkin, PARK-PINK1, and PARK-DJ1. It followed MDSGene's standardized data extraction protocol and screened a total of 3652 citations and is based on fully curated phenotypic and genotypic data on >1100 patients with recessively inherited PD because of 221 different disease-causing mutations in Parkin, PINK1, or DJ1. All these data are also available in an easily searchable online database (www.mdsgene.org), which also provides descriptive summary statistics on phenotypic and genetic data. Despite the high degree of missingness of phenotypic features and unsystematic reporting of genotype data in the original literature, the present review recapitulates many of the previously described findings including early onset (median age at onset of ∼30 years for carriers of at least 2 mutations in any of the 3 genes) of an overall clinically typical form of PD with excellent treatment response, dystonia and dyskinesia being relatively common and cognitive decline relatively uncommon. However, when comparing actual data with common expert knowledge in previously published reviews, we detected several discrepancies. We conclude that systematic reporting of phenotypes is a pressing need in light of increasingly available molecular genetic testing and the emergence of first gene-specific therapies entering clinical trials. © 2018 International Parkinson and Movement Disorder Society. © 2018 International Parkinson and Movement Disorder Society.

Temporal distribution of endogenous retinoids in the embryonic mouse mandible.

PubMed

Beeman, C S; Kronmiller, J E

1994-09-01

Retinoids play an important part in embryonic pattern formation. They are necessary for normal differentiation of odontogenic tissues and, in excess, disrupt the pattern of tooth formation. Excess retinoids produce supernumerary buds of the dental lamina in the diastema region of the mouse embryonic mandible where teeth do not normally form. This effect is coincident with an increase in epithelial proliferation and an alteration in epidermal growth factor mRNA expression (a gene product necessary for tooth formation). It was found by high-performance liquid chromatography that endogenous retinoids are present in the developing murine mandible and that concentrations of some retinoids reach a peak at the time of the initiation of odontogenesis (dental lamina formation).

Alzheimer brain-derived tau oligomers propagate pathology from endogenous tau.

PubMed

Lasagna-Reeves, Cristian A; Castillo-Carranza, Diana L; Sengupta, Urmi; Guerrero-Munoz, Marcos J; Kiritoshi, Takaki; Neugebauer, Volker; Jackson, George R; Kayed, Rakez

2012-01-01

Intracerebral injection of brain extracts containing amyloid or tau aggregates in transgenic animals can induce cerebral amyloidosis and tau pathology. We extracted pure populations of tau oligomers directly from the cerebral cortex of Alzheimer disease (AD) brain. These oligomers are potent inhibitors of long term potentiation (LTP) in hippocampal brain slices and disrupt memory in wild type mice. We observed for the first time that these authentic brain-derived tau oligomers propagate abnormal tau conformation of endogenous murine tau after prolonged incubation. The conformation and hydrophobicity of tau oligomers play a critical role in the initiation and spread of tau pathology in the naïve host in a manner reminiscent of sporadic AD.

Proliferation of murine midbrain neural stem cells depends upon an endogenous sonic hedgehog (Shh) source.

PubMed

Martínez, Constanza; Cornejo, Víctor Hugo; Lois, Pablo; Ellis, Tammy; Solis, Natalia P; Wainwright, Brandon J; Palma, Verónica

2013-01-01

The Sonic Hedgehog (Shh) pathway is responsible for critical patterning events early in development and for regulating the delicate balance between proliferation and differentiation in the developing and adult vertebrate brain. Currently, our knowledge of the potential role of Shh in regulating neural stem cells (NSC) is largely derived from analyses of the mammalian forebrain, but for dorsal midbrain development it is mostly unknown. For a detailed understanding of the role of Shh pathway for midbrain development in vivo, we took advantage of mouse embryos with cell autonomously activated Hedgehog (Hh) signaling in a conditional Patched 1 (Ptc1) mutant mouse model. This animal model shows an extensive embryonic tectal hypertrophy as a result of Hh pathway activation. In order to reveal the cellular and molecular origin of this in vivo phenotype, we established a novel culture system to evaluate neurospheres (nsps) viability, proliferation and differentiation. By recreating the three-dimensional (3-D) microenvironment we highlight the pivotal role of endogenous Shh in maintaining the stem cell potential of tectal radial glial cells (RGC) and progenitors by modulating their Ptc1 expression. We demonstrate that during late embryogenesis Shh enhances proliferation of NSC, whereas blockage of endogenous Shh signaling using cyclopamine, a potent Hh pathway inhibitor, produces the opposite effect. We propose that canonical Shh signaling plays a central role in the control of NSC behavior in the developing dorsal midbrain by acting as a niche factor by partially mediating the response of NSC to epidermal growth factor (EGF) and fibroblast growth factor (FGF) signaling. We conclude that endogenous Shh signaling is a critical mechanism regulating the proliferation of stem cell lineages in the embryonic dorsal tissue.

Attenuating endogenous Fgfr2b ligands during bleomycin-induced lung fibrosis does not compromise murine lung repair

PubMed Central

MacKenzie, BreAnne; Henneke, Ingrid; Hezel, Stefanie; Al Alam, Denise; El Agha, Elie; Chao, Cho-Ming; Quantius, Jennifer; Wilhelm, Jochen; Jones, Matthew; Goth, Kerstin; Li, Xiaokun; Seeger, Werner; Königshoff, Melanie; Herold, Susanne; Rizvanov, Albert A.; Günther, Andreas

2015-01-01

Fibroblast growth factors (Fgfs) mediate organ repair. Lung epithelial cell overexpression of Fgf10 postbleomycin injury is both protective and therapeutic, characterized by increased survival and attenuated fibrosis. Exogenous administration of FGF7 (palifermin) also showed prophylactic survival benefits in mice. The role of endogenous Fgfr2b ligands on bleomycin-induced lung fibrosis is still elusive. This study reports the expression of endogenous Fgfr2b ligands, receptors, and signaling targets in wild-type mice following bleomycin lung injury. In addition, the impact of attenuating endogenous Fgfr2b-ligands following bleomycin-induced fibrosis was tested by using a doxycycline (dox)-based inducible, soluble, dominant-negative form of the Fgfr2b receptor. Double-transgenic (DTG) Rosa26rtTA/+;tet(O)solFgfr2b mice were validated for the expression and activity of soluble Fgfr2b (failure to regenerate maxillary incisors, attenuated recombinant FGF7 signal in the lung). As previously reported, no defects in lung morphometry were detected in DTG (+dox) mice exposed from postnatal days (PN) 1 through PN105. Female single-transgenic (STG) and DTG mice were subjected to various levels of bleomycin injury (1.0, 2.0, and 3.0 U/kg). Fgfr2b ligands were attenuated either throughout injury (days 0–11; days 0–28) or during later stages (days 6–28 and 14–28). No significant changes in survival, weight, lung function, confluent areas of fibrosis, or hydroxyproline deposition were detected in DTG mice. These results indicate that endogenous Fgfr2b ligands do not significantly protect against bleomycin injury, nor do they expedite the resolution of bleomycin-induced lung injury in mice. PMID:25820524

C/EBPβ LIP and c-Jun synergize to regulate expression of the murine progesterone receptor.

PubMed

Wang, Weizhong; Do, Han Ngoc; Aupperlee, Mark D; Durairaj, Srinivasan; Flynn, Emily E; Miksicek, Richard J; Haslam, Sandra Z; Schwartz, Richard C

2018-06-02

CCAAT/enhancer binding protein β (C/EBPβ) is required for murine mammary ductal morphogenesis and alveologenesis. Progesterone is critical for proliferation and alveologenesis in adult mammary glands, and there is a similar requirement for progesterone receptor isoform B (PRB) in alveologenesis. We examined C/EBPβ regulation of PR expression. All three C/EBPβ isoforms, including typically inhibitory LIP, transactivated the PR promoter. LIP, particularly, strongly synergized with c-Jun to drive PR transcription. Endogenous C/EBPβ and c-Jun stimulated a PR promoter-reporter and these two factors showed promoter occupancy on the endogenous PR gene. Additionally, LIP overexpression elevated endogenous PR protein expression. In pregnancy, both PRB and the relative abundance of LIP among C/EBPβ isoforms increase. Consistent with a role in PRB expression, in vivo C/EBPβ and PR isoform A expression showed mutually exclusive localization in mammary epithelium, while C/EBPβ and PRB largely co-localized. We suggest a critical role for C/EBPβ, particularly LIP, in PRB expression. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Upregulating endogenous genes by an RNA-programmable artificial transactivator

PubMed Central

Fimiani, Cristina; Goina, Elisa; Mallamaci, Antonello

2015-01-01

To promote expression of endogenous genes ad libitum, we developed a novel, programmable transcription factor prototype. Kept together via an MS2 coat protein/RNA interface, it includes a fixed, polypeptidic transactivating domain and a variable RNA domain that recognizes the desired gene. Thanks to this device, we specifically upregulated five genes, in cell lines and primary cultures of murine pallial precursors. Gene upregulation was small, however sufficient to robustly inhibit neuronal differentiation. The transactivator interacted with target gene chromatin via its RNA cofactor. Its activity was restricted to cells in which the target gene is normally transcribed. Our device might be useful for specific applications. However for this purpose, it will require an improvement of its transactivation power as well as a better characterization of its target specificity and mechanism of action. PMID:26152305

Effect of caffeine on induction of endogenous type C virus in mouse cells in vitro

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

Niwa, O.; Sugahara, T.

1981-08-01

The effect of caffeine on the expression of murine endogenous virus in mouse cells induced by radiation and chemicals was studied. Postirradiation treatment of K-BALB cells with caffeine enhanced cell killing as well as the induction of xenotropic virus after ultraviolet light irradiation. The degree of enhancement for the virus induction was comparable to that for cell killing. On the other hand, colony-forming ability and the expression of xenotropic virus of K-BALB cells after X-irradiation were unaffected by caffeine. These data suggest a linear relationship between the degree of endogenous virus expression and the amount of lethal damages after irradiation.more » For induction by halogenated pyrimidines, a 24-hr incubation of AKR2B cells with caffeine after 5-iodo-2'-deoxyuridine treatment resulted in marked suppression of the expression of ecotropic virus. On the contrary, in K-BALB cells, caffeine exerted only a small effect on 5-iodo-2'-deoxyuridine-induced expression of ecotropic and xenotropic viruses. These results indicate that, although using the same inducing agent, the pathway of endogenous virus induction may be different for AKR2B cells and for K-BALB cells.« less

Analysis of alpha hemoglobin stabilizing protein overexpression in murine β-thalassemia

PubMed Central

Nasimuzzaman, Md; Khandros, Eugene; Wang, Xiaomei; Kong, Yi; Zhao, Huifen; Weiss, David; Rivella, Stefano; Weiss, Mitchell J.; Persons, Derek A.

2013-01-01

Excess free α-globin is cytotoxic and contributes to the pathophysiology of β-thalassemia. Alpha hemoglobin stabilizing protein (AHSP) is a molecular chaperone that binds free α-globin to promote its folding and inhibit its ability to produce damaging reactive oxygen species. Reduced AHSP levels correlate with increased severity of β-thalassemia in some human cohorts, but causal mechanistic relationships are not established for these associations. We used transgenic and lentiviral gene transfer methods to investigate whether supraphysiologic AHSP levels could mitigate the severity of β-thalassemia intermedia by providing an increased sink for the excess pool of α-globin chains. We tested wild-type AHSP and two mutant versions with amino acid substitutions that confer 3- or 13-fold higher affinity for α-globin. Erythroid overexpression of these AHSP proteins up to 11-fold beyond endogenous levels had no major effects on hematologic parameters in β-thalassemic animals. Our results demonstrate that endogenous AHSP is not limiting for α-globin detoxification in a murine model of β-thalassemia. PMID:20815047

Vaccination directed against the human endogenous retrovirus-K (HERV-K) gag protein slows HERV-K gag expressing cell growth in a murine model system.

PubMed

Kraus, Benjamin; Fischer, Katrin; Sliva, Katja; Schnierle, Barbara S

2014-03-26

Human endogenous retroviruses (HERVs) are remnants of ancestral infections and chromosomally integrated in all cells of an individual, are transmitted only vertically and are defective in viral replication. However enhanced expression of HERV-K accompanied by the emergence of anti-HERV-K-directed immune responses has been observed inter-alia in HIV-infected individuals and tumor patients. Therefore HERV-K might serve as a tumor-specific antigen or even as a constant target for the development of an HIV vaccine. To verify our hypothesis, we tested the immunogenicity of HERV-K Gag by using a recombinant vaccinia virus (MVA-HKcon) expressing the HERV-K Gag protein and established an animal model to test its vaccination efficacy. Murine renal carcinoma cells (Renca) were genetically altered to express E. coli beta-galactosidase (RLZ cells) and the HERV-K Gag protein (RLZ-HKGag cells). Subcutaneous application of RLZ-HKGag cells into syngenic BALB/c mice resulted in the formation of local tumors in MVA vaccinated mice. MVA-HKcon vaccination reduced the tumor growth. Furthermore, intravenous injection of RLZ-HKGag cells led to the formation of pulmonary metastases. Vaccination of tumor-bearing mice with MVA-HKcon drastically reduced the number of pulmonary RLZ-HKGag tumor nodules compared to vaccination with wild-type MVA. The data demonstrate that HERV-K Gag is a useful target for vaccine development and might offer new treatment opportunities for cancer patients.

SIMILAR PATTERNS OF MITOCHONDRIAL VULNERABILITY AND RESCUE INDUCED BY GENETIC MODIFICATION OF α-SYNUCLEIN, PARKIN AND DJ-1 IN C. ELEGANS*

PubMed Central

Westlund, Beth; Perier, Celine; Burnam, Lucinda; Sluder, Anne; Hoener, Marius; Rodrigues, Cecilia MP; Alfonso, Aixa; Steer, Clifford; Liu, Leo; Przedborski, Serge; Wolozin, Benjamin

2014-01-01

How genetic and environmental factors interact in Parkinson’s disease is poorly understood. We have now compared the patterns of vulnerability and rescue of C. elegans with genetic modifications of three different genetic factors implicated in PD. We observed that expressing α-synuclein, deleting parkin (K08E3.7) or knocking down DJ-1 (B0432.2) or parkin, produces similar patterns of pharmacological vulnerability and rescue. C. elegans lines with these genetic changes were more vulnerable than non-transgenic nematodes to mitochondrial complex I inhibitors, including rotenone, fenperoximate, pyridaben or stigmatellin. In contrast, the genetic manipulations did not increase sensitivity to paraquat, sodium azide, divalent metal ions (FeII or CuII) or etoposide compared to non-transgenic nematodes. Each of the PD-related lines was also partially rescued by the anti-oxidant probucol, the mitochondrial complex II activator, D-β-hydroxybutyrate (DβHB) or the anti-apoptotic bile acid tauroursodeoxycholic acid (TUDCA). Complete protection in all lines was achieved by combining DβHB with TUDCA but not with probucol. These results show that diverse PD-related genetic modifications disrupt mitochondrial function in C. elegans, and they raise the possibility that mitochondrial disruption is a pathway shared in common by many types of familial PD. PMID:16239214

Frequent Infection of Human Cancer Xenografts with Murine Endogenous Retroviruses in Vivo

PubMed Central

Naseer, Asif; Terry, Anne; Gilroy, Kathryn; Kilbey, Anna; Watts, Ciorsdaidh; Mackay, Nancy; Bell, Margaret; Mason, Susan; Blyth, Karen; Cameron, Ewan; Neil, James C.

2015-01-01

Infection of human cancer xenografts in mice with murine leukemia viruses (MLVs) is a long-standing observation, but the likelihood of infection in vivo and its biological consequences are poorly understood. We therefore conducted a prospective study in commonly used xenograft recipient strains. From BALB/c nude mice engrafted with MCF7 human mammary carcinoma cells, we isolated a virus that was virtually identical to Bxv1, a locus encoding replication-competent xenotropic MLV (XMLV). XMLV was detected in 9/17 (53%) independently isolated explants. XMLV was not found in primary leukemias or in THP1 leukemia cells grown in Bxv1-negative NSG (NOD/SCID/γCnull) mice, although MCF7 explants harbored replication-defective MLV proviruses. To assess the significance of infection for xenograft behavior in vivo, we examined changes in growth and global transcription in MCF7 and the highly susceptible Raji Burkitt lymphoma cell line chronically infected with XMLV. Raji cells showed a stronger transcriptional response that included up-regulation of chemokines and effectors of innate antiviral immunity. In conclusion, the risk of de novo XMLV infection of xenografts is high in Bxv1 positive mice, while infection can have positive or negative effects on xenograft growth potential with significant consequences for interpretation of many xenograft studies. PMID:25912714

Are endogenous feline leukemia viruses really endogenous?

PubMed

Stewart, H; Jarrett, O; Hosie, M J; Willett, B J

2011-10-15

Full length endogenous feline leukemia virus (FeLV) proviruses exist within the genomes of many breeds of domestic cat raising the possibility that they may also exist in a transmissible exogenous form. Such viruses would share receptor usage with the recombinant FeLV-B subgroup, a viral subgroup that arises in vivo by recombination between exogenous subgroup A virus (FeLV-A) and endogenous FeLV. Accordingly, all isolates of FeLV-B made to date have contained a "helper" FeLV-A, consistent with their recombinatorial origin. In order to assess whether endogenous viruses are transmitted between cats, we examined primary isolates of FeLV for which the viral subgroup had been determined for the presence of a subgroup B virus that lacked an FeLV-A. Here we describe the identification of two primary field isolates of FeLV (2518 and 4314) that appeared to contain subgroup B virus only by classical interference assays, raising the possibility of between-host transmission of endogenous FeLV. Sequencing of the env gene and U3 region of the 3' long terminal repeat (LTR) confirmed that both viral genomes contained endogenous viral env genes. However the viral 3' LTRs appeared exogenous in origin with a putative 3' recombination breakpoint residing at the 3' end of the env gene. Further, the FeLV-2518 virions also co-packaged a truncated FeLV-A genome containing a defective env gene, termed FeLV-2518(A) whilst no helper subgroup A viral genome was detected in virions of FeLV-4314. The acquisition of an exogenous LTR by the endogenous FeLV in 4314 may have allowed a recombinant FeLV variant to outgrow an exogenous FeLV-A virus that was presumably present during first infection. Given time, a similar evolution may also occur within the 2518 isolate. The data suggest that endogenous FeLVs may be mobilised by acquisition of exogenous LTRs yielding novel viruses that type biologically as FeLV-B. Copyright © 2011 Elsevier B.V. All rights reserved.

Endogenous antipyretics.

PubMed

Roth, Joachim

2006-09-01

The febrile increase of body temperature is regarded as a component of the complex host response to infection or inflammation that accompanies the activation of the immune system. Late phases of fever appear mediated by pro-inflammatory cytokines called endogenous pyrogens. The rise of body temperature is beneficial because it accelerates several components of the activated immune system. To prevent an excessive and dangerous rise of body temperature the febrile response is controlled, limited in strength and duration, and sometimes even prevented by the actions of endogenous antipyretic substances liberated systemically or within the brain during fever. In most cases the antipyretic effects are achieved by an inhibitory influence on the formation or action of endogenous pyrogens, or by effects on neuronal thermoregulatory circuits that are activated during fever. Endogenous antipyretic substances include steroid hormones, neuropeptides, cytokines and other molecules. It is the purpose of this review to consider the current state in the research on endogenous antipyretic systems.

Further comparisons of endogenous pyrogens and leukocytic endogenous mediators.

PubMed

Kampschmidt, R F; Upchurch, H F; Worthington, M L

1983-07-01

It was recently shown (Murphy et al., Infect. Immun. 34:177-183), that rabbit macrophages produce two biochemically and immunologically distinct endogenous pyrogens. One of these has or copurifies with substances having a molecular weight of 13,000 and a pI of 7.3. This protein was produced by blood monocytes or inflammatory cells elicited in 16-h rabbit peritoneal exudates. These acute peritoneal exudates were produced by the intraperitoneal injection of large volumes of saline containing shellfish glycogen. When the leukocytes in these exudates were washed and incubated at 37 degrees C in saline, they released an endogenous pyrogen. The injection of this pyrogen into rabbits, rats, or mice caused the biological manifestations which have been attributed to leukocytic endogenous mediator. These effects were increases in blood neutrophils, the lowering of plasma iron and zinc levels, and the increased synthesis of the acute-phase proteins. The other rabbit endogenous pyrogen seems to be a family of proteins with isoelectric points between 4.5 and 5.0. These proteins are produced by macrophages in the lung, liver, or in chronic peritoneal exudates. In these experiments, the lower-isoelectric-point endogenous pyrogens were produced by macrophages from the peritoneal cavity of rabbits that had been injected 4 days earlier with 50 ml of light mineral oil. These rabbit pyrogens were found to have leukocytic endogenous mediator activity in mice but to be completely inactive in rats. When injected into rabbits, these proteins produced fever, lowered plasma iron, increased blood neutrophils, but failed to elevate plasma fibrinogen.

Further comparisons of endogenous pyrogens and leukocytic endogenous mediators.

PubMed Central

Kampschmidt, R F; Upchurch, H F; Worthington, M L

1983-01-01

It was recently shown (Murphy et al., Infect. Immun. 34:177-183), that rabbit macrophages produce two biochemically and immunologically distinct endogenous pyrogens. One of these has or copurifies with substances having a molecular weight of 13,000 and a pI of 7.3. This protein was produced by blood monocytes or inflammatory cells elicited in 16-h rabbit peritoneal exudates. These acute peritoneal exudates were produced by the intraperitoneal injection of large volumes of saline containing shellfish glycogen. When the leukocytes in these exudates were washed and incubated at 37 degrees C in saline, they released an endogenous pyrogen. The injection of this pyrogen into rabbits, rats, or mice caused the biological manifestations which have been attributed to leukocytic endogenous mediator. These effects were increases in blood neutrophils, the lowering of plasma iron and zinc levels, and the increased synthesis of the acute-phase proteins. The other rabbit endogenous pyrogen seems to be a family of proteins with isoelectric points between 4.5 and 5.0. These proteins are produced by macrophages in the lung, liver, or in chronic peritoneal exudates. In these experiments, the lower-isoelectric-point endogenous pyrogens were produced by macrophages from the peritoneal cavity of rabbits that had been injected 4 days earlier with 50 ml of light mineral oil. These rabbit pyrogens were found to have leukocytic endogenous mediator activity in mice but to be completely inactive in rats. When injected into rabbits, these proteins produced fever, lowered plasma iron, increased blood neutrophils, but failed to elevate plasma fibrinogen. PMID:6862633

Suppression of Murine Retrovirus Polypeptide Termination: Effect of Amber Suppressor tRNA on the Cell-Free Translation of Rauscher Murine Leukemia Virus, Moloney Murine Leukemia Virus, and Moloney Murine Sarcoma Virus 124 RNA

PubMed Central

Murphy, Edwin C.; Wills, Norma; Arlinghaus, Ralph B.

1980-01-01

The effect of suppressor tRNA's on the cell-free translation of several leukemia and sarcoma virus RNAs was examined. Yeast amber suppressor tRNA (amber tRNA) enhanced the synthesis of the Rauscher murine leukemia virus and clone 1 Moloney murine leukemia virus Pr200gag-pol polypeptides by 10- to 45-fold, but at the same time depressed the synthesis of Rauscher murine leukemia virus Pr65gag and Moloney murine leukemia virus Pr63gag. Under suppressor-minus conditions, Moloney murine leukemia virus Pr70gag was present as a closely spaced doublet. Amber tRNA stimulated the synthesis of the “upper” Moloney murine leukemia virus Pr70gag polypeptide. Yeast ochre suppressor tRNA appeared to be ineffective. Quantitative analyses of the kinetics of viral precursor polypeptide accumulation in the presence of amber tRNA showed that during linear protein synthesis, the increase in accumulated Moloney murine leukemia virus Pr200gag-pol coincided closely with the molar loss of Pr63gag. Enhancement of Pr200gag-pol and Pr70gag by amber tRNA persisted in the presence of pactamycin, a drug which blocks the initiation of protein synthesis, thus arguing for the addition of amino acids to the C terminus of Pr63gag as the mechanism behind the amber tRNA effect. Moloney murine sarcoma virus 124 30S RNA was translated into four major polypeptides, Pr63gag, P42, P38, and P23. In the presence of amber tRNA, a new polypeptide, Pr67gag, appeared, whereas Pr63gag synthesis was decreased. Quantitative estimates indicated that for every 1 mol of Pr67gag which appeared, 1 mol of Pr63gag was lost. Images PMID:7373716

Characterization of Macrophage Endogenous S-Nitrosoproteome Using a Cysteine-Specific Phosphonate Adaptable Tag in Combination with TiO2 Chromatography.

PubMed

Ibáñez-Vea, María; Huang, Honggang; Martínez de Morentin, Xabier; Pérez, Estela; Gato, Maria; Zuazo, Miren; Arasanz, Hugo; Fernández-Irigoyen, Joaquin; Santamaría, Enrique; Fernandez-Hinojal, Gonzalo; Larsen, Martin R; Escors, David; Kochan, Grazyna

2018-03-02

Protein S-nitrosylation is a cysteine post-translational modification mediated by nitric oxide. An increasing number of studies highlight S-nitrosylation as an important regulator of signaling involved in numerous cellular processes. Despite the significant progress in the development of redox proteomic methods, identification and quantification of endogeneous S-nitrosylation using high-throughput mass-spectrometry-based methods is a technical challenge because this modification is highly labile. To overcome this drawback, most methods induce S-nitrosylation chemically in proteins using nitrosylating compounds before analysis, with the risk of introducing nonphysiological S-nitrosylation. Here we present a novel method to efficiently identify endogenous S-nitrosopeptides in the macrophage total proteome. Our approach is based on the labeling of S-nitrosopeptides reduced by ascorbate with a cysteine specific phosphonate adaptable tag (CysPAT), followed by titanium dioxide (TiO 2 ) chromatography enrichment prior to nLC-MS/MS analysis. To test our procedure, we performed a large-scale analysis of this low-abundant modification in a murine macrophage cell line. We identified 569 endogeneous S-nitrosylated proteins compared with 795 following exogenous chemically induced S-nitrosylation. Importantly, we discovered 579 novel S-nitrosylation sites. The large number of identified endogenous S-nitrosylated peptides allowed the definition of two S-nitrosylation consensus sites, highlighting protein translation and redox processes as key S-nitrosylation targets in macrophages.

Endogenous murine leukemia virus-encoded proteins in radiation leukemias of BALB/c mice

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

Tress, E.; Pierotti, M.; DeLeo, A.B.

1982-02-01

To explore the role of endogenous retroviruses in radiation-induced leukemogenesis in the mouse, we have examined virus-encoded proteins in nine BALB/c leukemias by pulsechase labeling procedures and serological typing with monospecific and monoclonal antibodies. The major gag precursor protein, Pr65/sup gag/, was observed in all cases, but only three leukemias expressed detectable amounts of the glycosylated gag species, gP95/sup gag/, or its precursor, Pr75/sup gag/. No evidence was found for synthesis of gag-host fusion proteins. None of the leukemias released infectious xenotropic or dualtropic virus, but all nine expressed at least one env protein with xenotropic properties. In two instancesmore » a monoclonal antibody, 35/56, which is specific for the NuLV G/sub IX/ antigen, displayed a distinctive reactivity with this class of env protein, although this antibody is unreactive with replicating xenotropic viruses. An ecotropic/xenotropic recombinant env protein with the same 35/56 phenotype was observed in a leukemia induced by a strongly leukemogenic virus isolated from a BALB/c radiation leukemia.« less

Genetic mapping of xenotropic murine leukemia virus-inducing loci in five mouse strains

PubMed Central

1980-01-01

A single mendelian gene was identified for induction of the endogenous xenotropic murine leukemia virus in five mouse strains (C57BL/10, C57L, C57BR, AKR, and BALB/c). This locus, designated Bxv-1, mapped to the same site on chromosome 1 in all strains: Id-1-Pep-3-[Bxv-1-Lp]. Thus, inducibility loci for xenotropic virus are more limited in number and chromosomal distribution than ecotropic inducibility loci. Virus expression in mice with Bxv-1 was induced by treatment of fibroblasts with 5-iododeoxyuridine or by exposure of spleen cells to a B cell mitogen, bacterial lipopolysaccharide. An analysis of the hamster X mouse somatic cell hybrids indicated that chromosome 1, alone, was sufficient for virus induction. PMID:6249881

Genetic mapping of xenotropic murine leukemia virus-inducing loci in five mouse strains.

PubMed

Kozak, C A; Rowe, W P

1980-07-01

A single mendelian gene was identified for induction of the endogenous xenotropic murine leukemia virus in five mouse strains (C57BL/10, C57L, C57BR, AKR, and BALB/c). This locus, designated Bxv-1, mapped to the same site on chromosome 1 in all strains: Id-1-Pep-3-[Bxv-1-Lp]. Thus, inducibility loci for xenotropic virus are more limited in number and chromosomal distribution than ecotropic inducibility loci. Virus expression in mice with Bxv-1 was induced by treatment of fibroblasts with 5-iododeoxyuridine or by exposure of spleen cells to a B cell mitogen, bacterial lipopolysaccharide. An analysis of the hamster X mouse somatic cell hybrids indicated that chromosome 1, alone, was sufficient for virus induction.

Endogenous Lunar Volatiles

NASA Astrophysics Data System (ADS)

McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Anand, M.; Boyce, J. W.; Burney, D.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Klima, R. L.; Magna, T.; Ni, P.; Steenstra, E.; Tartèse, R.; Vander Kaaden, K. E.

2018-04-01

This abstract discusses numerous outstanding questions on the topic of endogenous lunar volatiles that will need to be addressed in the coming years. Although substantial insights into endogenous lunar volatiles have been gained, more work remains.

Resolvin E1 (RX-10001) reduces corneal epithelial barrier disruption and protects against goblet cell loss in a murine model of dry eye.

PubMed

de Paiva, Cintia S; Schwartz, C Eric; Gjörstrup, Per; Pflugfelder, Stephen C

2012-11-01

Resolvin E1 (RvE1; RX-10001) belongs to a new class of endogenous immunoregulating mediators, originally identified as a metabolite of the omega-3 polyunsaturated fatty acid, eicosapentaenoic acid. Based on its proven efficacy in models of chronic inflammation, this study investigated the efficacy of resolvin E1 in a murine model of dry eye. C57/B6 mice, aged 6 to 8 weeks, were treated with systemic scopolamine and exposed to air draft and low humidity for 16 hours/day for 5 days and allocated to the following groups: unexposed controls, disease controls, treatment with vehicle or RvE1 delivered topically as its methyl ester prodrug, RX-10005, to enhance corneal surface penetration. Treatment was initiated at the time of desiccating stress induction. Treatment efficacy was assessed by corneal permeability using Oregon Green Dextran and by conjunctival goblet cell density using periodic acid-Schiff reagent. RvE1 reduced the increase in corneal staining by 80% compared with untreated disease controls. Goblet cell density was reduced by 20% in disease controls but fully maintained in the group receiving RvE1. RvE1, delivered as its methyl ester prodrug, improved the outcome measures of corneal staining and goblet cell density in this murine model of dry eye, indicating the potential utility of endogenous resolvins and resolvin analogues in the treatment of dry eye.

Expression of endogenous mouse APP modulates β-amyloid deposition in hAPP-transgenic mice.

PubMed

Steffen, Johannes; Krohn, Markus; Schwitlick, Christina; Brüning, Thomas; Paarmann, Kristin; Pietrzik, Claus U; Biverstål, Henrik; Jansone, Baiba; Langer, Oliver; Pahnke, Jens

2017-06-20

Amyloid-β (Aβ) deposition is one of the hallmarks of the amyloid hypothesis in Alzheimer's disease (AD). Mouse models using APP-transgene overexpression to generate amyloid plaques have shown to model only certain parts of the disease. The extent to which the data from mice can be transferred to man remains controversial. Several studies have shown convincing treatment results in reducing Aβ and enhancing cognition in mice but failed totally in human. One model-dependent factor has so far been almost completely neglected: the endogenous expression of mouse APP and its effects on the transgenic models and the readout for therapeutic approaches.Here, we report that hAPP-transgenic models of amyloidosis devoid of endogenous mouse APP expression (mAPP-knockout / mAPPko) show increased amounts and higher speed of Aβ deposition than controls with mAPP. The number of senile plaques and the level of aggregated hAβ were elevated in mAPPko mice, while the deposition in cortical blood vessels was delayed, indicating an alteration in the general aggregation propensity of hAβ together with endogenous mAβ. Furthermore, the cellular response to Aβ deposition was modulated: mAPPko mice developed a pronounced and age-dependent astrogliosis, while microglial association to amyloid plaques was diminished. The expression of human and murine aggregation-prone proteins with differing amino acid sequences within the same mouse model might not only alter the extent of deposition but also modulate the route of pathogenesis, and thus, decisively influence the study outcome, especially in translational research.

Selenium suppresses leukemia through the action of endogenous eicosanoids

PubMed Central

Gandhi, Ujjawal H.; Kaushal, Naveen; Hegde, Shailaja; Finch, Emily R.; Kudva, Avinash K.; Kennett, Mary J.; Jordan, Craig T.; Paulson, Robert F.; Prabhu, K. Sandeep

2014-01-01

Eradicating cancer stem-like cells (CSC) may be essential to fully eradicate cancer. Metabolic changes in CSC could hold a key to their targeting. Here we report that the dietary micronutrient selenium can trigger apoptosis of CSC derived from chronic or acute myelogenous leukemias when administered at supraphysiological but non-toxic doses. In leukemia CSC, selenium treatment activated ATM-p53-dependent apoptosis accompanied by increased intracellular levels of reactive oxygen species. Importantly, the same treatment did not trigger apoptosis in hematopoietic stem cells. Serial transplantation studies with BCR-ABL-expressing CSC revealed that the selenium status in mice was a key determinant of CSC survival. Selenium action relied upon the endogenous production of the cyclooxygenase-derived prostaglandins Δ12-PGJ2 and 15d-PGJ2. Accordingly, non-steroidal anti-inflammatory drugs and NADPH oxidase inhibitors abrogated the ability of selenium to trigger apoptosis in leukemia CSC. Our results reveal how selenium-dependent modulation of arachidonic acid metabolism can be directed to trigger apoptosis of primary human and murine CSC in leukemia. PMID:24872387

Treatment response in Kawasaki disease is associated with sialylation levels of endogenous but not therapeutic intravenous immunoglobulin G.

PubMed

Ogata, Shohei; Shimizu, Chisato; Franco, Alessandra; Touma, Ranim; Kanegaye, John T; Choudhury, Biswa P; Naidu, Natasha N; Kanda, Yutaka; Hoang, Long T; Hibberd, Martin L; Tremoulet, Adriana H; Varki, Ajit; Burns, Jane C

2013-01-01

Although intravenous immunoglobulin (IVIG) is highly effective in Kawasaki disease (KD), mechanisms are not understood and 10-20% of patients are treatment-resistant, manifesting a higher rate of coronary artery aneurysms. Murine models suggest that α2-6-linked sialic acid (α2-6Sia) content of IVIG is critical for suppressing inflammation. However, pro-inflammatory states also up-regulate endogenous levels of β-galactoside:α2-6 sialyltransferase-I (ST6Gal-I), the enzyme that catalyzes addition of α2-6Sias to N-glycans. We asked whether IVIG failures correlated with levels of α2-6Sia on infused IVIG or on the patient's own endogenous IgG. We quantified levels of α2-6Sia in infused IVIG and endogenous IgG from 10 IVIG-responsive and 10 resistant KD subjects using multiple approaches. Transcript levels of ST6GAL1, in patient whole blood and B cell lines were evaluated by RT-PCR. Plasma soluble (s)ST6Gal-I levels were measured by ELISA. There was no consistent difference in median sialylation levels of infused IVIG between groups. However, α2-6Sia levels in endogenous IgG, ST6GAL1 transcript levels, and ST6Gal-I protein in serum from IVIG-resistant KD subjects were lower than in responsive subjects at both pre-treatment and one-year time points (p <0.001, respectively). Our data indicate sialylation levels of therapeutic IVIG are unrelated to treatment response in KD. Rather, lower sialylation of endogenous IgG and lower blood levels of ST6GALI mRNA and ST6Gal-I enzyme predict therapy resistance. These differences were stable over time, suggesting a genetic basis. Because IVIG-resistance increases risk of coronary artery aneurysms, our findings have important implications for the identification and treatment of such individuals.

Production of endogenous pyrogen.

PubMed

Dinarello, C A

1979-01-01

The production and release of endogenous pyrogen by the host is the first step in the pathogenesis of fever. Endogenous pyrogen is a low-molecular-weight protein released from phagocytic leukocytes in response to several substances of diverse nature. Some of these agents stimulate production of endogenous pyrogen because they are toxic; others act as antigens and interact with either antibody or sensitized lymphocytes in order to induce its production. Some tumors of macrophage origin produce the molecule spontaneously. Whatever the mechanism involved, endogenous pyrogen is synthesized following transcription of new DNA and translation of mRNA into new protein. Once synthesis is completed, the molecule is released without significant intracellular storage. Recent evidence suggests that following release, molecular aggregates form which are biologically active. In its monomer form, endogenous pyrogen is a potent fever-producing substance and mediates fever by its action on the thermoregulatory center.

Possible human endogenous cryogens.

PubMed

Shido, Osamu; Sugimoto, Naotoshi

2011-06-01

Anapyrexia, which is a regulated fall in core temperature, is beneficial for animals and humans when the oxygen supply is limited, e.g., hypoxic, ischemic, or histotoxic hypoxia, since at low body temperature the tissues require less oxygen due to Q(10). Besides hypoxia, anapyrexia can be induced various exogenous and endogenous substances, named cryogens. However, there are only a few reports investigating endogenous cryogens in mammals. We have experienced one patient who suffered from severe hypothermia. The patient seemed to be excessively producing endogenous peptidergic cryogenic substances the molecular weight of which may be greater than 30 kDa. In animal studies, the patient's cryogen appeared to affect metabolic functions, including thermogenic threshold temperatures, and then to produce hypothermia. Since endogenous cryogenic substances may be regarded as useful tool in human activities, e.g., during brain hypothermia therapy or staying in a space station or spaceship, further studies may be needed to identify human endogenous cryogens.

Preparation of Murine Submandibular Salivary Gland for Upright Intravital Microscopy.

PubMed

Ficht, Xenia; Thelen, Flavian; Stolp, Bettina; Stein, Jens V

2018-05-07

The submandibular salivary gland (SMG) is one of the three major salivary glands, and is of interest for many different fields of biological research, including cell biology, oncology, dentistry, and immunology. The SMG is an exocrine gland comprised of secretory epithelial cells, myofibroblasts, endothelial cells, nerves, and extracellular matrix. Dynamic cellular processes in the rat and mouse SMG have previously been imaged, mostly using inverted multi-photon microscope systems. Here, we describe a straightforward protocol for the surgical preparation and stabilization of the murine SMG in anesthetized mice for in vivo imaging with upright multi-photon microscope systems. We present representative intravital image sets of endogenous and adoptively transferred fluorescent cells, including the labeling of blood vessels or salivary ducts and second harmonic generation to visualize fibrillar collagen. In sum, our protocol allows for surgical preparation of mouse salivary glands in upright microscopy systems, which are commonly used for intravital imaging in the field of immunology.

Removal of xenotropic murine leukemia virus by nanocellulose based filter paper.

PubMed

Asper, M; Hanrieder, T; Quellmalz, A; Mihranyan, A

2015-11-01

The removal of xenotrpic murine leukemia virus (xMuLV) by size-exclusion filter paper composed of 100% naturally derived cellulose was validated. The filter paper was produced using cellulose nanofibers derived from Cladophora sp. algae. The filter paper was characterized using atomic force microscopy, scanning electron microscopy, helium pycnometry, and model tracer (100 nm latex beads and 50 nm gold nanoparticles) retention tests. Following the filtration of xMuLV spiked solutions, LRV ≥5.25 log10 TCID50 was observed, as limited by the virus titre in the feed solution and sensitivity of the tissue infectivity test. The results of the validation study suggest that the nanocellulose filter paper is useful for removal of endogenous rodent retroviruses and retrovirus-like particles during the production of recombinant proteins. Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

An endogenous 55 kDa TNF receptor mediates cell death in a neural cell line.

PubMed

Sipe, K J; Srisawasdi, D; Dantzer, R; Kelley, K W; Weyhenmeyer, J A

1996-06-01

Tumor necrosis factor-alpha (TNF) is associated with developmental and injury-related events in the central nervous system (CNS). In the present study, we have examined the role of TNF on neurons using the clonal murine neuroblastoma line, N1E-115 (N1E). N1E cells represent a well-defined model for studying neuronal development since they can be maintained as either undifferentiated, mitotically active neuroblasts or as differentiated, mature neurons. Northern and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that both undifferentiated and differentiated N1Es express transcripts for the 55 kDa TNF receptor (TNFR), but not the 75 kDa TNFR. The biological activity of the expressed TNF receptor was demonstrated by a dose dependent cytotoxicity to either recombinant murine or human TNF when the cells were incubated with the transcriptional inhibitor actinomycin D. The lack of the 75 kDa receptor mRNA expression and the dose dependent response to rHuTNF, an agonist specific for the murine 55 kDa receptor, suggest that the TNF induced cytotoxicity is mediated through the 55 kDa receptor in both the undifferentiated and differentiated N1Es. Light microscopic observations, flow cytometric analysis of hypodiploid DNA, and electrophoretic analysis of nucleosomal DNA fragmentation of N1Es treated with actinomycin D and TNF revealed features characteristic of both necrotic and apoptotic cell death. These findings demonstrate that blast and mature N1E cells express the 55 kDa TNF receptor which is responsible for inducing both necrotic and apoptotic death in these cells. The observation that actinomycin D renders N1E cells susceptible to the cytotoxic effects of TNF indicates that a sensitization step, such as removal of an endogenous protective factor or viral-mediated inhibition of transcription, may be necessary for TNF cytotoxicity in neurons.

Treatment Response in Kawasaki Disease Is Associated with Sialylation Levels of Endogenous but Not Therapeutic Intravenous Immunoglobulin G

PubMed Central

Ogata, Shohei; Shimizu, Chisato; Franco, Alessandra; Touma, Ranim; Kanegaye, John T.; Choudhury, Biswa P.; Naidu, Natasha N.; Kanda, Yutaka; Hoang, Long T.; Hibberd, Martin L.; Tremoulet, Adriana H.; Varki, Ajit; Burns, Jane C.

2013-01-01

Objectives Although intravenous immunoglobulin (IVIG) is highly effective in Kawasaki disease (KD), mechanisms are not understood and 10-20% of patients are treatment-resistant, manifesting a higher rate of coronary artery aneurysms. Murine models suggest that α2-6-linked sialic acid (α2-6Sia) content of IVIG is critical for suppressing inflammation. However, pro-inflammatory states also up-regulate endogenous levels of β-galactoside:α2-6 sialyltransferase-I (ST6Gal-I), the enzyme that catalyzes addition of α2-6Sias to N-glycans. We asked whether IVIG failures correlated with levels of α2-6Sia on infused IVIG or on the patient’s own endogenous IgG. Methods We quantified levels of α2-6Sia in infused IVIG and endogenous IgG from 10 IVIG-responsive and 10 resistant KD subjects using multiple approaches. Transcript levels of ST6GAL1, in patient whole blood and B cell lines were evaluated by RT-PCR. Plasma soluble (s)ST6Gal-I levels were measured by ELISA. Results There was no consistent difference in median sialylation levels of infused IVIG between groups. However, α2-6Sia levels in endogenous IgG, ST6GAL1 transcript levels, and ST6Gal-I protein in serum from IVIG-resistant KD subjects were lower than in responsive subjects at both pre-treatment and one-year time points (p <0.001, respectively). Conclusions Our data indicate sialylation levels of therapeutic IVIG are unrelated to treatment response in KD. Rather, lower sialylation of endogenous IgG and lower blood levels of ST6GALI mRNA and ST6Gal-I enzyme predict therapy resistance. These differences were stable over time, suggesting a genetic basis. Because IVIG-resistance increases risk of coronary artery aneurysms, our findings have important implications for the identification and treatment of such individuals. PMID:24324693

δ-Aminolevulinic acid transport in murine mammary adenocarcinoma cells is mediated by beta transporters

PubMed Central

Bermúdez Moretti, M; Correa García, S; Perotti, C; Batlle, A; Casas, A

2002-01-01

δ-aminolevulinic acid, the precursor of porphyrin biosynthesis has been used to induce the endogenous synthesis of the photosensitiser protoporphyrin IX for photodynamic therapy in the treatment of various tumours. The aim of this work was to characterise the δ-aminolevulinic acid transport system in the murine mammary adenocarcinoma cell line LM3 using 14C-δ-aminolevulinic acid, to finally improve δ-aminolevulinic acid incorporation in mammalian cells. Our results showed that δ-aminolevulinic acid is incorporated into these cells by two different mechanisms, passive diffusion which is important at the beginning of the incubation, and active transport. Specificity assays suggested that the transporter involved in δ-aminolevulinic acid incorporation is a BETA transporter, probably GAT-2. British Journal of Cancer (2002) 87, 471–474. doi:10.1038/sj.bjc.6600481 www.bjcancer.com © 2002 Cancer Research UK PMID:12177786

Nitric oxide protects murine embryonic liver cells (BNL CL.2) from cytotoxicity induced by glucose deprivation.

PubMed

Pae, H O; Kim, H G; Paik, Y S; Paik, S G; Kim, Y M; Oh, G S; Chung, H T

2000-03-01

We investigated the protective effects of nitric oxide on cell death of murine embryonic liver cells (BNL CL.2) after glucose deprivation. Endogenous nitric oxide production by BNL CL.2 cells was induced by 6 hr pretreatment with interferon-gamma and lipopolysaccharide. We used sodium nitroprusside and S-nitroso-L-glutathione as exogenous nitric oxide-generating compounds. All agents were used at doses that did not show direct cytotoxicity as measured by crystal violet staining assay. In the BNL CL.2 cells, the viability dropped very steeply after 24 hr incubation with glucose-free media. Endogenous nitric oxide produced by treatment of the cells with interferon-gamma and lipopolysaccharide protected the cells from glucose deprivation-induced cytotoxicity, but did not protect them in the presence of the nitric oxide synthesis inhibitor, N(G)-monomethyl-L-arginine. Exogenous nitric oxide protected the cells from glucose deprivation-induced cytotoxicity in a concentration-dependent manner. Cytoprotection by nitric oxide donors was abolished by the use of nitric oxide scavenger, 2-phenyl-4,4,5,5,-tetramethylimidazole, but not by the soluble guanosine cyclase inhibitor, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one. In addition, cytoprotective effects comparable to endogenous or exogenous nitric oxide were not observed when the cells were incubated with dibutyl guanosine 3',5'-cyclic monophosphate. Based upon these results, we suggest that nitric oxide may enhance the cell survival of BNL CL.2 cells after glucose deprivation via a guanosine 3',5'-cyclic monophosphate-independent pathway.

Murine Typhus

PubMed Central

Dzul-Rosado, Karla R; Zavala Velázquez, Jorge Ernesto; Zavala-Castro, Jorge

2012-01-01

Rickettsia typhi: is an intracellular bacteria who causes murine typhus. His importance is reflected in the high frequency founding specific antibodies against Rickettsia typhi in several worldwide seroepidemiological studies, the seroprevalence ranging between 3-36%. Natural reservoirs of R. typhi are rats (some species belonging the Rattus Genus) and fleas (Xenopsylla cheopis) are his vector. This infection is associated with overcrowding, pollution and poor hygiene. Typically presents fever, headache, rash on trunk and extremities, in some cases may occur organ-specific complications, affecting liver, kidney, lung or brain. Initially the disease is very similar to other diseases, is very common to confuse the murine typhus with Dengue fever, therefore, ignorance of the disease is a factor related to complications or non-specific treatments for the resolution of this infection. This paper presents the most relevant information to consider about the rickettsiosis caused by Rickettsia typhi. PMID:24893060

Murine epithelial cells: isolation and culture.

PubMed

Davidson, Donald J; Gray, Michael A; Kilanowski, Fiona M; Tarran, Robert; Randell, Scott H; Sheppard, David N; Argent, Barry E; Dorin, Julia R

2004-08-01

We describe an air-liquid interface primary culture method for murine tracheal epithelial cells on semi-permeable membranes, forming polarized epithelia with a high transepithelial resistance, differentiation to ciliated and secretory cells, and physiologically appropriate expression of key genes and ion channels. We also describe the isolation of primary murine nasal epithelial cells for patch-clamp analysis, generating polarised cells with physiologically appropriate distribution and ion channel expression. These methods enable more physiologically relevant analysis of murine airway epithelial cells in vitro and ex vivo, better utilisation of transgenic mouse models of human pulmonary diseases, and have been approved by the European Working Group on CFTR expression.

The tryptophan-derived endogenous arylhydrocarbon receptor ligand 6-formylindolo[3,2-b]carbazole (FICZ) is a nanomolar UVA-photosensitizer in epidermal keratinocytes

PubMed Central

Williams, Joshua D.; Cabello, Christopher M.; Qiao, Shuxi; Wondrak, Georg T.

2014-01-01

Endogenous UVA-chromophores may act as sensitizers of oxidative stress underlying cutaneous photoaging and photocarcinogenesis, but the molecular identity of non-DNA key chromophores displaying UVA-driven photodyamic activity in human skin remains largely undefined. Here we report that 6-formylindolo[3,2-b]carbazole (FICZ), a tryptophan photoproduct and endogenous high affinity aryl hydrocarbon receptor (AhR) agonist, acts as a nanomolar photosensitizer potentiating UVA-induced oxidative stress irrespective of AhR ligand activity. In human HaCaT and primary epidermal keratinocytes, photodynamic induction of apoptosis was elicited by the combined action of solar simulated UVA and FICZ, whereas exposure to the isolated action of UVA or FICZ did not impair viability. In a human epidermal tissue reconstruct, FICZ/UVA-cotreatment caused pronounced phototoxicity inducing keratinocyte cell death, and FICZ photodynamic activity was also substantiated in a murine skin exposure model. Array analysis revealed pronounced potentiation of cellular heat shock, ER stress, and oxidative stress response gene expression observed only upon FICZ/UVA-cotreatment. FICZ photosensitization caused intracellular oxidative stress, and comet analysis revealed introduction of formamidopyrimidine-DNA glycosylase (FPG)-sensitive oxidative DNA lesions suppressible by antioxidant cotreatment. Taken together, our data demonstrate that the endogenous AhR ligand FICZ displays nanomolar photodynamic activity representing a molecular mechanism of UVA-induced photooxidative stress potentially operative in human skin. PMID:25431849

Cytokines as endogenous pyrogens.

PubMed

Dinarello, C A

1999-03-01

Cytokines are pleiotropic molecules mediating several pathologic processes. Long before the discovery of cytokines as immune system growth factors or as bone marrow stimulants, investigators learned a great deal about cytokines when they studied them as the endogenous mediators of fever. The terms "granulocytic" or "endogenous pyrogen" were used to describe substances with the biologic property of fever induction. Today, we recognize that pyrogenicity is a fundamental biologic property of several cytokines and hence the clinically recognizeable property of fever links host perturbations during disease with fundamental perturbations in cell biology. In this review, the discoveries made on endogenous pyrogens are revisited, with insights into the importance of the earlier work to the present-day understanding of cytokines in health and in disease.

Endogenous retroviral insertion in Cryge in the mouse No3 cataract mutant

PubMed Central

Nag, Nabanita; Peterson, Katherine; Wyatt, Keith; Hess, Sonja; Ray, Sugata; Favor, Jack; Bogani, Debora; Lyon, Mary; Wistow, Graeme

2007-01-01

No3 (nuclear opacity 3) is a novel congenital nuclear cataract in mice. Microsatellite mapping placed the No3 locus on chromosome 1 between D1Mit480 (32cM) and D1Mit7 (41cM), a region containing seven crystallin genes; Cryba2 and the Cryga-Crygf cluster. Although polymorphic variants were observed, no candidate mutations were found for six of the genes. However, DNA walking identified a murine endogenous retrovirus (IAPLTR1: ERVK) insertion in exon 3 of Cryge, disrupting the coding sequence for γE-crystallin. Recombinant protein for the mutant γE was completely insoluble. The No3 cataract is mild compared with the effects of similar mutations of γE. Quantitative RT-PCR showed that γE/F mRNA levels are reduced in No3, suggesting that the relatively mild phenotype results from suppression of γE levels due to ERVK insertion. However, the severity of cataract is also strain dependent suggesting that genetic background modifiers also play a role in the development of opacity. PMID:17223009

Stress-Induced Neurogenic Inflammation in Murine Skin Skews Dendritic Cells Towards Maturation and Migration

PubMed Central

Joachim, Ricarda Alcira; Handjiski, Bori; Blois, Sandra Maria; Hagen, Evelin; Paus, Ralf; Arck, Petra Clara

2008-01-01

The skin continuously serves as a biosensor of multiple exogenous stressors and integrates the resulting responses with an individual’s central and peripheral endogenous response systems to perceived stress; it also acts to protect against external challenges such as wounding and infection. We have previously shown in mice that stress induces nerve growth factor- and substance P-dependent neurogenic inflammation, which includes the prominent clustering of MHC class II+ cells. Because the contribution of dendritic cells (DCs) in response to stress is not well understood, we examined the role of DCs in neurogenic inflammation in murine skin using a well-established murine stress model. We show that sound stress increases the number of intradermal langerin+ and CD11c+ DCs and induces DC maturation, as indicated by the up-regulated expression of CD11c, MHC class II, and intercellular adhesion molecule-1 (ICAM-1). Blocking of ICAM-1/leukocyte function-associated antigen-1 interactions significantly abrogated the stress-induced numeric increase, maturation, and migration of dermal DCs in vivo and also reduced stress-induced keratinocyte apoptosis and endothelial cell expression of ICAM-1. In conclusion, stress exposure causes a state of immune alertness in the skin. Such adaptation processes may ensure protection from possible infections on wounding by stressors, such as attack by predators. However, present-day stressors have changed and such adaptations appear redundant and may overrun skin homeostasis by inducing immune dermatoses. PMID:18832583

Isolation and Differentiation of Murine Macrophages.

PubMed

Rios, Francisco J; Touyz, Rhian M; Montezano, Augusto C

2017-01-01

Macrophages play a major role in inflammation, wound healing, and tissue repair. Infiltrated monocytes differentiate into different macrophage subtypes with protective or pathogenic activities in vascular lesions. In the heart and vascular tissues, pathological activation promotes cardiovascular inflammation and remodeling and there is increasing evidence that macrophages play important mechanisms in this environment. Primary murine macrophages can be obtained from: bone marrow by different treatments (granulocyte-macrophage colony-stimulating factor-GM-CSF, macrophage colony-stimulating factor-M-CSF or supernatant of murine fibroblast L929), peritoneal cavity (resident or thioglycolate elicit macrophages), from the lung (alveolar macrophages) or from adipose tissue. In this chapter we describe some protocols to obtain primary murine macrophages and how to identify a pure macrophage population or activation phenotypes using different markers.

Endogenous pyrogen-like substance produced by reptiles.

PubMed

Bernheim, H A; Kluger, M J

1977-06-01

1. Injection of lizards (Dipsosaurus dorsalis) with rabbit endogenous pyrogen led to a fever. Injections with denatured endogenous pyrogen did not affect body temperature. 2. Injection of lizards with lizard endogenous pyrogen led to a fever of short duration, while injection of denatured lizard endogenous pyrogen produced no change in body temperature. 3. These data support the hypothesis that the febrile mechanism observed in the higher vertebrates has its origins in some primitive vertebrate.

Germ line transmission of a yeast artificial chromosome spanning the murine [alpha][sub 1](I) collagen locus

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

Strauss, W.M.; Dausman, J.; Beard, C.

Molecular complementation of mutant phenotypes by transgenic technology is a potentially important tool for gene identification. A technology was developed to allow the transfer of a physically intact yeast artificial chromosome (YAC) into the germ line of the mouse. A purified 150-kilobase YAC encompassing the murine gene Col1a1 was efficiently introduced into embryonic stem (ES) cells via lipofection. Chimeric founder mice were derived from two transfected ES cell clones. These chimeras transmitted the full length transgene through the germ line, generating two transgenic mouse strains. Transgene expression was visualized as nascent transcripts in interphase nuclei and quantitated by ribonuclease protectionmore » analysis. Both assays indicated that the transgene was expressed at levels comparable to the endogenous collagen gene. 32 refs., 3 figs., 1 tab.« less

Endogenous pyrogen-like substance produced by reptiles.

PubMed Central

Bernheim, H A; Kluger, M J

1977-01-01

1. Injection of lizards (Dipsosaurus dorsalis) with rabbit endogenous pyrogen led to a fever. Injections with denatured endogenous pyrogen did not affect body temperature. 2. Injection of lizards with lizard endogenous pyrogen led to a fever of short duration, while injection of denatured lizard endogenous pyrogen produced no change in body temperature. 3. These data support the hypothesis that the febrile mechanism observed in the higher vertebrates has its origins in some primitive vertebrate. PMID:874874

Murine Typhus, Reunion, France, 2011–2013

PubMed Central

Camuset, Guillaume; Socolovschi, Cristina; Moiton, Marie-Pierre; Kuli, Barbara; Foucher, Aurélie; Poubeau, Patrice; Borgherini, Gianandrea; Wartel, Guillaume; Audin, Héla; Raoult, Didier; Filleul, Laurent; Parola, Philippe; Pagès, Fréderic

2015-01-01

Murine typhus case was initially identified in Reunion, France, in 2012 in a tourist. Our investigation confirmed 8 autochthonous cases that occurred during January 2011–January 2013 in Reunion. Murine typhus should be considered in local patients and in travelers returning from Reunion who have fevers of unknown origin. PMID:25625653

Hypothesis: Leukocyte Endogenous Mediator/Endogenous Pyrogen/Lymphocyte-Activating Factor Modulates the Development of Nonspecific and Specific Immunity and Affects Nutritional Status

DTIC Science & Technology

1982-04-01

Hypothesis: leukocyte endogenous mediator/ endogenous pyrogen /lymphocyte-activating factor modulates the development of nonspecific and specific... endogenous pyrogen /lympho- NI cyte-activating factor (LEM/EP/LAF) integrates the host’s nonspecific and specific immune responses to infection by...mediator/ endogenous pyrogen /lymphocyte-activating factor, nonspecific and specific immunity, infection, metabolism, nutrition. Introduction LAF which lead

Endogenous digitalis-like factors.

PubMed

Schoner, W

1992-01-01

The postulate of a natriuretic factor inhibiting the sodium pump in the kidney led to the detection of increased concentrations of endogenous digitalis-like factors in blood after salt loading, in essential hypertension, in pregnancy-induced hypertension and in chronic hypervolaemia. The recent isolation of ouabain or a close isomer thereof from human plasma and the demonstration of a compound similar if not identical to digoxin in adrenals and human urine shows that mammals like non-vertebrates and toads may synthesize cardiac glycosides in their adrenals and possibly in hypothalamus. The hypothalamus also forms other compounds of unknown structure which bind to the cardiac glycoside receptor site. The differential functions of endogenously formed ouabain and of a digoxin-like substance are unclear. The detailed knowledge of the physiological role of both endogenously formed cardiac glycosides in the regulation of blood pressure has still to be worked out.

CrxOS maintains the self-renewal capacity of murine embryonic stem cells

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

Saito, Ryota; Yamasaki, Tokiwa; Nagai, Yoko

2009-12-25

Embryonic stem (ES) cells maintain pluripotency by self-renewal. Several homeoproteins, including Oct3/4 and Nanog, are known to be key factors in maintaining the self-renewal capacity of ES cells. However, other genes required for the mechanisms underlying this process are still unclear. Here we report the identification by in silico analysis of a homeobox-containing gene, CrxOS, that is specifically expressed in murine ES cells and is essential for their self-renewal. ES cells mainly express the short isoform of endogenous CrxOS. Using a polyoma-based episomal expression system, we demonstrate that overexpression of the CrxOS short isoform is sufficient for maintaining the undifferentiatedmore » morphology of ES cells and stimulating their proliferation. Finally, using RNA interference, we show that CrxOS is essential for the self-renewal of ES cells, and provisionally identify foxD3 as a downstream target gene of CrxOS. To our knowledge, ours is the first delineation of the physiological role of CrxOS in ES cells.« less

Leucine-Rich Repeat Kinase 2 interacts with Parkin, DJ-1 and PINK-1 in a Drosophila melanogaster model of Parkinson's disease.

PubMed

Venderova, Katerina; Kabbach, Ghassan; Abdel-Messih, Elizabeth; Zhang, Yi; Parks, Robin J; Imai, Yuzuru; Gehrke, Stephan; Ngsee, Johnny; Lavoie, Matthew J; Slack, Ruth S; Rao, Yong; Zhang, Zhuohua; Lu, Bingwei; Haque, M Emdadul; Park, David S

2009-11-15

Mutations in the LRRK2 gene are the most common genetic cause of familial Parkinson's disease (PD). However, its physiological and pathological functions are unknown. Therefore, we generated several independent Drosophila lines carrying WT or mutant human LRRK2 (mutations in kinase, COR or LRR domains, resp.). Ectopic expression of WT or mutant LRRK2 in dopaminergic neurons caused their significant loss accompanied by complex age-dependent changes in locomotor activity. Overall, the ubiquitous expression of LRRK2 increased lifespan and fertility of the flies. However, these flies were more sensitive to rotenone. LRRK2 expression in the eye exacerbated retinal degeneration. Importantly, in double transgenic flies, various indices of the eye and dopaminergic survival were modified in a complex fashion by a concomitant expression of PINK1, DJ-1 or Parkin. This evidence suggests a genetic interaction between these PD-relevant genes.

Endogenous nandrolone metabolites in human urine: preliminary results to discriminate between endogenous and exogenous origin.

PubMed

Le Bizec, Bruno; Bryand, Fabrice; Gaudin, Isabelle; Monteau, Fabrice; Poulain, Frédéric; Andre, François

2002-02-01

When administered to human subjects, nandrolone is metabolized into two main products, 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE). Recent studies demonstrated the endogenous production of these compounds in man at concentrations very close to the threshold of the International Olympic Committee (IOC), i.e. 2 ng/ml. Because the possibility of reaching or exceeding this fateful limit is difficult to exclude, a complementary biochemical parameter is necessary for the differentiation of endogenous 19-NA and 19-NE production from residues resulting from nandrolone consumption. We measured the endogenous concentrations of 19-NA and 19-NE in 385 urine samples from professional football players, and we studied the phase II metabolite composition in individuals excreting the highest concentrations. The results showed that around 30% of endogenous 19-norandrosterone was sulfo-conjugated, whereas 100% of 19-norandrosterone was excreted conjugated to a glucuronic acid when nandrolone was administered. This significant qualitative difference appears to be a promising complementary criterion to more definitively conclude about an athlete's culpability, especially when nandrolone metabolites are found in the low ng/ml range.

Ciliary neurotrophic factor is an endogenous pyrogen.

PubMed

Shapiro, L; Zhang, X X; Rupp, R G; Wolff, S M; Dinarello, C A

1993-09-15

Fever is initiated by the action of polypeptide cytokines called endogenous pyrogens, which are produced by the host during inflammation, trauma, or infection and which elevate the thermoregulatory set point in the hypothalamus. Ciliary neurotrophic factor (CNTF) supports the differentiation and survival of central and peripheral neurons. We describe the activity of CNTF as intrinsically pyrogenic in the rabbit. CNTF induced a monophasic fever which rose rapidly (within the first 12 min) following intravenous injection; CNTF fever was blocked by pretreatment with indomethacin. The fever induced by CNTF was not due to contaminating endotoxins. Increasing doses of CNTF resulted in prolongation of the fever, suggesting the subsequent induction of additional endogenous pyrogenic activity. After passive transfer of plasma obtained during CNTF-induced fever, endogenous pyrogen activity was not present in the circulation; CNTF also did not induce the endogenous pyrogens interleukin 1, tumor necrosis factor, or interleukin 6 in vitro. Nevertheless, a second endogenous pyrogen may originate within the central nervous system following the systemic injection of CNTF. Of the four endogenous pyrogens described to date (interleukin 1, tumor necrosis factor, interferon, and interleukin 6), CNTF, like interleukin 6, utilizes the cell-surface gp 130 signal-transduction apparatus.

Commonly dysregulated genes in murine APL cells

PubMed Central

Yuan, Wenlin; Payton, Jacqueline E.; Holt, Matthew S.; Link, Daniel C.; Watson, Mark A.; DiPersio, John F.; Ley, Timothy J.

2007-01-01

To identify genes that are commonly dysregulated in a murine model of acute promyelocytic leukemia (APL), we first defined gene expression patterns during normal murine myeloid development; serial gene expression profiling studies were performed with primary murine hematopoietic progenitors that were induced to undergo myeloid maturation in vitro with G-CSF. Many genes were reproducibly expressed in restricted developmental “windows,” suggesting a structured hierarchy of expression that is relevant for the induction of developmental fates and/or differentiated cell functions. We compared the normal myeloid developmental transcriptome with that of APL cells derived from mice expressing PML-RARα under control of the murine cathepsin G locus. While many promyelocyte-specific genes were highly expressed in all APL samples, 116 genes were reproducibly dysregulated in many independent APL samples, including Fos, Jun, Egr1, Tnf, and Vcam1. However, this set of commonly dysregulated genes was expressed normally in preleukemic, early myeloid cells from the same mouse model, suggesting that dysregulation occurs as a “downstream” event during disease progression. These studies suggest that the genetic events that lead to APL progression may converge on common pathways that are important for leukemia pathogenesis. PMID:17008535

Nitric Oxide-Mediated Tumoricidal Activity of Murine Microglial Cells12

PubMed Central

Brantley, Emily C; Guo, Lixia; Zhang, Chenyu; Lin, Qingtang; Yokoi, Kenji; Langley, Robert R; Kruzel, Ewa; Maya, Marva; Kim, Seung Wook; Kim, Sun-Jin; Fan, Dominic; Fidler, Isaiah J

2010-01-01

Experimental metastases in the brain of mice are infiltrated by microglia, and parabiosis experiments of green fluorescent protein (GFP+) and GFP- mice revealed that these microglia are derived from circulating monocytes (GFP+, F4/80+, and CD68+). These findings raised the question as to whether microglia (specialized macrophages) possess tumoricidal activity. C8-B4 murine microglia cells were incubated in vitro in medium (control) or in medium containing both lipopolysaccharide and interferon-γ. Control microglia were not tumoricidal against a number of murine and human tumor cells, whereas lipopolysaccharide/interferon-γ-activated microglia lysed murine and human tumor cells by release of nitric oxide. Parallel experiments with murine peritoneal macrophages produced identical results. Neither activated microglia nor activated macrophages lysed nontumorigenic murine or human cells. Collectively, these data demonstrate that brain metastasis-associated microglia are derived from circulating mononuclear cells and exhibit selective and specific tumoricidal activity. PMID:21151477

The locus control region is required for association of the murine β-globin locus with engaged transcription factories during erythroid maturation

PubMed Central

Ragoczy, Tobias; Bender, M.A.; Telling, Agnes; Byron, Rachel; Groudine, Mark

2006-01-01

We have examined the relationship between nuclear localization and transcriptional activity of the endogenous murine β-globin locus during erythroid differentiation. Murine fetal liver cells were separated into distinct erythroid maturation stages by fluorescence-activated cell sorting, and the nuclear position of the locus was determined at each stage. We find that the β-globin locus progressively moves away from the nuclear periphery with increasing maturation. Contrary to the prevailing notion that the nuclear periphery is a repressive compartment in mammalian cells, βmajor-globin expression begins at the nuclear periphery prior to relocalization. However, relocation of the locus to the nuclear interior with maturation is accompanied by an increase in βmajor-globin transcription. The distribution of nuclear polymerase II (Pol II) foci also changes with erythroid differentiation: Transcription factories decrease in number and contract toward the nuclear interior. Moreover, both efficient relocalization of the β-globin locus from the periphery and its association with hyperphosphorylated Pol II transcription factories require the locus control region (LCR). These results suggest that the LCR-dependent association of the β-globin locus with transcriptionally engaged Pol II foci provides the driving force for relocalization of the locus toward the nuclear interior during erythroid maturation. PMID:16705039

Ciliary neurotrophic factor is an endogenous pyrogen.

PubMed Central

Shapiro, L; Zhang, X X; Rupp, R G; Wolff, S M; Dinarello, C A

1993-01-01

Fever is initiated by the action of polypeptide cytokines called endogenous pyrogens, which are produced by the host during inflammation, trauma, or infection and which elevate the thermoregulatory set point in the hypothalamus. Ciliary neurotrophic factor (CNTF) supports the differentiation and survival of central and peripheral neurons. We describe the activity of CNTF as intrinsically pyrogenic in the rabbit. CNTF induced a monophasic fever which rose rapidly (within the first 12 min) following intravenous injection; CNTF fever was blocked by pretreatment with indomethacin. The fever induced by CNTF was not due to contaminating endotoxins. Increasing doses of CNTF resulted in prolongation of the fever, suggesting the subsequent induction of additional endogenous pyrogenic activity. After passive transfer of plasma obtained during CNTF-induced fever, endogenous pyrogen activity was not present in the circulation; CNTF also did not induce the endogenous pyrogens interleukin 1, tumor necrosis factor, or interleukin 6 in vitro. Nevertheless, a second endogenous pyrogen may originate within the central nervous system following the systemic injection of CNTF. Of the four endogenous pyrogens described to date (interleukin 1, tumor necrosis factor, interferon, and interleukin 6), CNTF, like interleukin 6, utilizes the cell-surface gp 130 signal-transduction apparatus. PMID:8378338

Anatomy and Histology of the Human and Murine Prostate.

PubMed

Ittmann, Michael

2018-05-01

The human and murine prostate glands have similar functional roles in the generation of seminal fluid to assist in reproduction. There are significant differences in the anatomy and histology of murine and human prostate and knowledge of the normal anatomy and histology of the murine prostate is essential to interpreting changes in genetically engineered mouse models. In this review, the normal anatomy and histology of both human and mouse prostate will be described. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

Live Imaging of Endogenous PSD-95 Using ENABLED: A Conditional Strategy to Fluorescently Label Endogenous Proteins

PubMed Central

Fortin, Dale A.; Tillo, Shane E.; Yang, Guang; Rah, Jong-Cheol; Melander, Joshua B.; Bai, Suxia; Soler-Cedeño, Omar; Qin, Maozhen; Zemelman, Boris V.; Guo, Caiying

2014-01-01

Stoichiometric labeling of endogenous synaptic proteins for high-contrast live-cell imaging in brain tissue remains challenging. Here, we describe a conditional mouse genetic strategy termed endogenous labeling via exon duplication (ENABLED), which can be used to fluorescently label endogenous proteins with near ideal properties in all neurons, a sparse subset of neurons, or specific neuronal subtypes. We used this method to label the postsynaptic density protein PSD-95 with mVenus without overexpression side effects. We demonstrated that mVenus-tagged PSD-95 is functionally equivalent to wild-type PSD-95 and that PSD-95 is present in nearly all dendritic spines in CA1 neurons. Within spines, while PSD-95 exhibited low mobility under basal conditions, its levels could be regulated by chronic changes in neuronal activity. Notably, labeled PSD-95 also allowed us to visualize and unambiguously examine otherwise-unidentifiable excitatory shaft synapses in aspiny neurons, such as parvalbumin-positive interneurons and dopaminergic neurons. Our results demonstrate that the ENABLED strategy provides a valuable new approach to study the dynamics of endogenous synaptic proteins in vivo. PMID:25505322

Language Deficits as a Preclinical Window into Parkinson's Disease: Evidence from Asymptomatic Parkin and Dardarin Mutation Carriers.

PubMed

García, Adolfo M; Sedeño, Lucas; Trujillo, Natalia; Bocanegra, Yamile; Gomez, Diana; Pineda, David; Villegas, Andrés; Muñoz, Edinson; Arias, William; Ibáñez, Agustín

2017-02-01

The worldwide spread of Parkinson's disease (PD) calls for sensitive and specific measures enabling its early (or, ideally, preclinical) detection. Here, we use language measures revealing deficits in PD to explore whether similar disturbances are present in asymptomatic individuals at risk for the disease. We administered executive, semantic, verb-production, and syntactic tasks to sporadic PD patients, genetic PD patients with PARK2 (parkin) or LRRK2 (dardarin) mutation, asymptomatic first-degree relatives of the latter with similar mutations, and socio-demographically matched controls. Moreover, to detect sui generis language disturbances, we ran analysis of covariance tests using executive functions as covariate. The two clinical groups showed impairments in all measures, most of which survived covariation with executive functions. However, the key finding concerned asymptomatic mutation carriers. While these subjects showed intact executive, semantic, and action-verb production skills, they evinced deficits in a syntactic test with minimal working memory load. We propose that this sui generis disturbance may constitute a prodromal sign anticipating eventual development of PD. Moreover, our results suggest that mutations on specific genes (PARK2 and LRRK2) compromising basal ganglia functioning may be subtly related to language-processing mechanisms. (JINS, 2017, 23, 150-158).

Endogenous Pyrogen Physiology.

ERIC Educational Resources Information Center

Beisel, William R.

1980-01-01

Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

Low doses of paraquat and polyphenols prolong life span and locomotor activity in knock-down parkin Drosophila melanogaster exposed to oxidative stress stimuli: implication in autosomal recessive juvenile parkinsonism.

PubMed

Bonilla-Ramirez, Leonardo; Jimenez-Del-Rio, Marlene; Velez-Pardo, Carlos

2013-01-10

Previous studies have shown that polyphenols might be potent neuroprotective agents in Drosophila melanogaster wild type Canton-S acutely or chronically treated with paraquat (PQ), a selective toxin for elimination of dopaminergic (DAergic) neurons by oxidative stress (OS), as model of Parkinson's disease (PD). This study reports for the first time that knock-down (K-D) parkin Drosophila melanogaster (TH-GAL4; UAS-RNAi-parkin) chronically exposed to PQ (0.1-0.25 mM), FeSO(4) (Fe, 0.1mM), deferoxamine (DFO, 0.01 mM) alone or (0.1mM) PQ in combination with polyphenols propyl gallate (PG, 0.1mM) and epigallocathecin gallate (EGCG, 0.1, 0.5mM) showed significantly higher life span and locomotor activity than untreated K-D flies or treated with (1, 5, 20mM) PQ alone. Whilst gallic acid (GA, 0.1, 0.5mM) alone or in the presence of PQ provoked no effect on K-D flies, epicathecin (EC, 0.5mM) only showed a positive effect on prolonging K-D flies' life span. It is shown that PG (and EGCG) protected protocerebral posterolateral 1 (PPL1) DAergic neurons against PQ. Interestingly, the protective effect of low PQ concentrations, DFO and iron might be explained by a phenomenon known as "hormesis." However, pre-fed K-D flies with (0.1mM) PQ for 7 days and then exposed to (0.25 mM) for additional 8 days affect neither survival nor climbing of K-D Drosophila compared to flies treated with (0.25 mM) PQ alone. Remarkably, K-D flies treated with 0.1mM PQ (7 days) and then with (0.25 mM) PQ plus PG (8 days) behaved almost as flies treated with (0.25 mM) PQ. Taken these data suggest that antioxidant supplements that synergistically act with low pro-oxidant stimuli to prolong and increase locomotor activity become inefficient once a threshold of OS has been reached in K-D flies. Our present findings support the notion that genetically altered Drosophila melanogaster as suitable model to study genetic and environmental factors as causal and/or modulators in the development of autosomal

Endogenous timing factors in bird migration

NASA Technical Reports Server (NTRS)

Gwinner, E. G.

1972-01-01

Several species of warbler birds were observed in an effort to determine what initiates and terminates migration. Environmental and endogenous timing mechanisms were analyzed. The results indicate that endogenous stimuli are dominant factors for bird migration especially for long distances. It was concluded that environmental factors act as an assist mechanism.

Endogenous Peer Effects: Fact or Fiction?

ERIC Educational Resources Information Center

Yeung, Ryan; Nguyen-Hoang, Phuong

2016-01-01

The authors examine endogenous peer effects, which occur when a student's behavior or outcome is a function of the behavior or outcome of his or her peer group. Endogenous peer effects have important implications for educational policies such as busing, school choice and tracking. In this study, the authors quantitatively review the literature on…

Live imaging of endogenous PSD-95 using ENABLED: a conditional strategy to fluorescently label endogenous proteins.

PubMed

Fortin, Dale A; Tillo, Shane E; Yang, Guang; Rah, Jong-Cheol; Melander, Joshua B; Bai, Suxia; Soler-Cedeño, Omar; Qin, Maozhen; Zemelman, Boris V; Guo, Caiying; Mao, Tianyi; Zhong, Haining

2014-12-10

Stoichiometric labeling of endogenous synaptic proteins for high-contrast live-cell imaging in brain tissue remains challenging. Here, we describe a conditional mouse genetic strategy termed endogenous labeling via exon duplication (ENABLED), which can be used to fluorescently label endogenous proteins with near ideal properties in all neurons, a sparse subset of neurons, or specific neuronal subtypes. We used this method to label the postsynaptic density protein PSD-95 with mVenus without overexpression side effects. We demonstrated that mVenus-tagged PSD-95 is functionally equivalent to wild-type PSD-95 and that PSD-95 is present in nearly all dendritic spines in CA1 neurons. Within spines, while PSD-95 exhibited low mobility under basal conditions, its levels could be regulated by chronic changes in neuronal activity. Notably, labeled PSD-95 also allowed us to visualize and unambiguously examine otherwise-unidentifiable excitatory shaft synapses in aspiny neurons, such as parvalbumin-positive interneurons and dopaminergic neurons. Our results demonstrate that the ENABLED strategy provides a valuable new approach to study the dynamics of endogenous synaptic proteins in vivo. Copyright © 2014 the authors 0270-6474/14/3416698-15$15.00/0.

Susceptibility of human liver cells to porcine endogenous retrovirus.

PubMed

Lin, Xinzi; Qi, Lin; Li, Zhiguo; Chi, Hao; Lin, Wanjun; Wang, Yan; Jiang, Zesheng; Pan, Mingxin; Gao, Yi

2013-12-01

The risk of porcine endogenous retrovirus infection is a major barrier for pig-to-human xenotransplant. Porcine endogenous retrovirus, present in porcine cells, can infect many human and nonhuman primate cells in vitro, but there is no evidence available about in vitro infection of human liver cells. We investigated the susceptibility of different human liver cells to porcine endogenous retrovirus. The supernatant from a porcine kidney cell line was added to human liver cells, including a normal hepatocyte cell line (HL-7702 cells), primary hepatocytes (Phh cells), and a liver stellate cell line (Lx-2 cells), and to human embryonic kidney cells as a reference control. Expression of the porcine endogenous retrovirus antigen p15E in the human cells was evaluated with polymerase chain reaction, reverse transcription-polymerase chain reaction, and Western blot. The porcine endogenous retrovirus antigen p15E was not expressed in any human liver cells (HL-7702, Phh, or Lx-2 cells) that had been exposed to supernatants from porcine kidney cell lines. Porcine endogenous retrovirus-specific fragments were amplified in human kidney cells. Human liver cells tested were not susceptible to infection by porcine endogenous retrovirus. Therefore, not all human cells are susceptible to porcine endogenous retrovirus.

Caprine PrP variants harboring Asp-146, His-154 and Gln-211 alleles display reduced convertibility upon interaction with pathogenic murine prion protein in scrapie infected cells.

PubMed

Kanata, Eirini; Arsenakis, Minas; Sklaviadis, Theodoros

2016-09-02

Scrapie, the prion disease of sheep and goats, is a devastating malady of small ruminants. Due to its infectious nature, epidemic outbreaks may occur in flocks/herds consisting of highly susceptible animals. Field studies identified scrapie-protective caprine PrP variants, harboring specific single amino acid changes (Met-142, Arg-143, Asp-146, Ser-146, His-154, Gln-211 and Lys-222). Their effects are under further evaluation, and aim to determine the most protective allele. We assessed some of these variants (Asp-146, His-154, Gln-211 and Lys-222), after their exogenous expression as murine-caprine chimeras in a scrapie- infected murine cell line. We report that exogenously expressed PrPs undergo conformational conversion upon interaction with the endogenous pathological murine prion protein (PrP SC ), which results in the detection of goat-specific and partially PK-resistant moieties. These moieties display a PK-resistance pattern distinct from the one detected in natural goat scrapie cases. Within this cellular model, distinct conformational conversion potentials were assigned to the tested variants. Molecules carrying the Asp-146, His-154 and Gln-211 alleles showed significantly lower conversion levels compared to wild type, confirming their protective effects against scrapie. Although we utilized a heterologous conversion system, this is to our knowledge, the first study of caprine PrP variants in a cellular context of scrapie, that confirms the protective effects of some of the studied alleles.

Are endogenous cardenolides controlled by atrial natriuretic peptide.

PubMed

Brar, Kanwarjeet S; Gao, Yonglin; El-Mallakh, Rif S

2016-07-01

Endogenous cardenolides are digoxin-like substances and ouabain-like substances that have been implicated in the pathogenesis of hypertension and mood disorders in clinical and pre-clinical studies. Regulatory signals for endogenous cardenolides are still unknown. These endogenous compounds are believed to be produced by the adrenal gland in the periphery and the hypothalamus in the central nervous system, and constitute part of an hormonal axis that may regulate the catalytic activity of the α subunit of Na(+)/K(+)-ATPase. A review of literature suggests that there is great overlap in physiological environments that are associated with either elevations or reductions in the levels of atrial natriuretic peptide (ANP) and endogenous cardenolides. This suggests that these two factors may share a common regulatory signal or perhaps that ANP may be involved in the regulation of endogenous cardenolides. Copyright © 2016. Published by Elsevier Ltd.

Endogenous versus exogenous shocks in systems with memory

NASA Astrophysics Data System (ADS)

Sornette, D.; Helmstetter, A.

2003-02-01

Systems with long-range persistence and memory are shown to exhibit different precursory as well as recovery patterns in response to shocks of exogenous versus endogenous origins. By endogenous, we envision either fluctuations resulting from an underlying chaotic dynamics or from a stochastic forcing origin which may be external or be an effective coarse-grained description of the microscopic fluctuations. In this scenario, endogenous shocks result from a kind of constructive interference of accumulated fluctuations whose impacts survive longer than the large shocks themselves. As a consequence, the recovery after an endogenous shock is in general slower at early times and can be at long times either slower or faster than after an exogenous perturbation. This offers the tantalizing possibility of distinguishing between an endogenous versus exogenous cause of a given shock, even when there is no “smoking gun”. This could help in investigating the exogenous versus self-organized origins in problems such as the causes of major biological extinctions, of change of weather regimes and of the climate, in tracing the source of social upheaval and wars, and so on. Sornette et al., Volatility fingerprints of large stocks: endogenous versus exogenous, cond-mat/0204626 has already shown how this concept can be applied concretely to differentiate the effects on financial markets of the 11 September 2001 attack or of the coup against Gorbachev on 19 August 1991 (exogenous) from financial crashes such as October 1987 (endogenous).

Genomic Flexibility of Human Endogenous Retrovirus Type K

PubMed Central

Dube, Derek; Contreras-Galindo, Rafael; He, Shirley; King, Steven R.; Gonzalez-Hernandez, Marta J.; Gitlin, Scott D.; Kaplan, Mark H.

2014-01-01

ABSTRACT Human endogenous retrovirus type K (HERV-K) proviruses are scattered throughout the human genome, but as no infectious HERV-K virus has been detected to date, the mechanism by which these viruses replicated and populated the genome remains unresolved. Here, we provide evidence that, in addition to the RNA genomes that canonical retroviruses package, modern HERV-K viruses can contain reverse-transcribed DNA (RT-DNA) genomes. Indeed, reverse transcription of genomic HERV-K RNA into the DNA form is able to occur in three distinct times and locations: (i) in the virus-producing cell prior to viral release, yielding a DNA-containing extracellular virus particle similar to the spumaviruses; (ii) within the extracellular virus particle itself, transitioning from an RNA-containing particle to a DNA-containing particle; and (iii) after entry of the RNA-containing virus into the target cell, similar to canonical retroviruses, such as murine leukemia virus and HIV. Moreover, using a resuscitated HERV-K virus construct, we show that both viruses with RNA genomes and viruses with DNA genomes are capable of infecting target cells. This high level of genomic flexibility historically could have permitted these viruses to replicate in various host cell environments, potentially assisting in their many integration events and resulting in their high prevalence in the human genome. Moreover, the ability of modern HERV-K viruses to proceed through reverse transcription and package RT-DNA genomes suggests a higher level of replication competency than was previously understood, and it may be relevant in HERV-K-associated human diseases. IMPORTANCE Retroviral elements comprise at least 8% of the human genome. Of all the endogenous retroviruses, HERV-K viruses are the most intact and biologically active. While a modern infectious HERV-K has yet to be found, HERV-K activation has been associated with cancers, autoimmune diseases, and HIV-1 infection. Thus, determining how this

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

Kao, Shyan-Yuan, E-mail: shyan-yuan_kao@meei.harvard.edu

Mutation of parkin is one of the most prevalent causes of autosomal recessive Parkinson's disease (PD). Parkin is an E3 ubiquitin ligase that acts on a variety of substrates, resulting in polyubiquitination and degradation by the proteasome or monoubiquitination and regulation of biological activity. However, the cellular functions of parkin that relate to its pathological involvement in PD are not well understood. Here we show that parkin is essential for optimal repair of DNA damage. Parkin-deficient cells exhibit reduced DNA excision repair that can be restored by transfection of wild-type parkin, but not by transfection of a pathological parkin mutant.more » Parkin also protects against DNA damage-induced cell death, an activity that is largely lost in the pathological mutant. Moreover, parkin interacts with the proliferating cell nuclear antigen (PCNA), a protein that coordinates DNA excision repair. These results suggest that parkin promotes DNA repair and protects against genotoxicity, and implicate DNA damage as a potential pathogenic mechanism in PD.« less

A Ratiometric Acoustogenic Probe for in Vivo Imaging of Endogenous Nitric Oxide.

PubMed

Reinhardt, Christopher J; Zhou, Effie Y; Jorgensen, Michael D; Partipilo, Gina; Chan, Jefferson

2018-01-24

Photoacoustic (PA) imaging is an emerging imaging modality that utilizes optical excitation and acoustic detection to enable high resolution at centimeter depths. The development of activatable PA probes can expand the utility of this technology to allow for detection of specific stimuli within live-animal models. Herein, we report the design, development, and evaluation of a series of Acoustogenic Probe(s) for Nitric Oxide (APNO) for the ratiometric, analyte-specific detection of nitric oxide (NO) in vivo. The best probe in the series, APNO-5, rapidly responds to NO to form an N-nitroso product with a concomitant 91 nm hypsochromic shift. This property enables ratiometric PA imaging upon selective irradiation of APNO-5 and the corresponding product, tAPNO-5. Moreover, APNO-5 displays the requisite photophysical characteristics for in vivo PA imaging (e.g., high absorptivity, low quantum yield) as well as high biocompatibility, stability, and selectivity for NO over a variety of biologically relevant analytes. APNO-5 was successfully applied to the detection of endogenous NO in a murine lipopolysaccharide-induced inflammation model. Our studies show a 1.9-fold increase in PA signal at 680 nm and a 1.3-fold ratiometric turn-on relative to a saline control.

ATR suppresses endogenous DNA damage and allows completion of homologous recombination repair.

PubMed

Brown, Adam D; Sager, Brian W; Gorthi, Aparna; Tonapi, Sonal S; Brown, Eric J; Bishop, Alexander J R

2014-01-01

DNA replication fork stalling or collapse that arises from endogenous damage poses a serious threat to genome stability, but cells invoke an intricate signaling cascade referred to as the DNA damage response (DDR) to prevent such damage. The gene product ataxia telangiectasia and Rad3-related (ATR) responds primarily to replication stress by regulating cell cycle checkpoint control, yet it's role in DNA repair, particularly homologous recombination (HR), remains unclear. This is of particular interest since HR is one way in which replication restart can occur in the presence of a stalled or collapsed fork. Hypomorphic mutations in human ATR cause the rare autosomal-recessive disease Seckel syndrome, and complete loss of Atr in mice leads to embryonic lethality. We recently adapted the in vivo murine pink-eyed unstable (pun) assay for measuring HR frequency to be able to investigate the role of essential genes on HR using a conditional Cre/loxP system. Our system allows for the unique opportunity to test the effect of ATR loss on HR in somatic cells under physiological conditions. Using this system, we provide evidence that retinal pigment epithelium (RPE) cells lacking ATR have decreased density with abnormal morphology, a decreased frequency of HR and an increased level of chromosomal damage.

The Endogenous-Exogenous Partition in Attribution Theory

ERIC Educational Resources Information Center

Kruglanski, Arie W.

1975-01-01

Within lay explanation of actions, several significant inferences are assumed to follow from the partition between endogenous and exogenous attributions. An endogenous action is judged to constitute an end in itself; an exogenous action is judged to serve as a means to some further end. (Editor/RK)

Genetic interactions in the spontaneous production of endogenous murine leukemia virus in low leukemic mouse strains

PubMed Central

1982-01-01

The spontaneous expression of ecotropic murine leukemia virus (MuLV) in spleen cells of BALB/c, C57BL/6 (B6), and derivative mice was examined as a function of age. The patterns of spontaneous virus induction in vivo correlate with the patterns of virus induction in vitro, which result from the action of two loci, Inc-l and Inb-l (7). Whereas mice carrying Inc-l or Inb-l have similar phenotypes in vitro, they have significantly different phenotypes in vivo. Mice of the Inb-l+/+ genotype, e.g., B6, rarely expressed MuLV, and the titer of MuLV recovered from rare MuLV-positive mice of this genotype was usually low. Mice of the Inc-l+/+ genotype, e.g., BALB/c, expressed low amounts of MuLV early in life, however, from 6-12 mo of age approximately one- half of the Inc-l+/+ mice expressed virus, frequently of high titer. Equal numbers of N-tropic and B-tropic MuLV were recovered from Inb-l+ mice, but predominantly N-tropic MuLV was recovered from Inc-l+ mice. Strains that carry dominant (+) alleles at both Inc-l and Inb-l show higher titers of MuLV earlier in life than strains that carry only Inc- l or Inb-l. The presence of dominant alleles at both loci results in the appearance of predominantly N-tropic virus early in life. These results demonstrate that the principal determinants of spontaneous virus expression in these low leukemic strains of mice are the In loci or genes linked to them. A further inference that can be drawn from these studies is that the appearance of B-tropic virus is by no means a random process but rather results from predictable patterns of MuLV expression and alteration. PMID:6284854

Measurement of lipocortin 1 levels in murine peripheral blood leukocytes by flow cytometry: modulation by glucocorticoids and inflammation.

PubMed

Perretti, M; Flower, R J

1996-06-01

1. Lipocortin 1 (LC1) immunoreactivity in murine peripheral blood leukocytes was quantified by use of a flow cytometric technique associated with a permeabilisation protocol with saponin. Using specific antisera raised against the whole protein or against its N-terminus peptide, cell-associated LC1-like immunoreactivity was easily detected in circulating neutrophils and monocytes, whereas very low levels were found in lymphocytes. Of the total protein measured 17.6% and 36% were associated with the external plasma membrane in neutrophils and monocytes, as assessed in the absence of cell permeabilisation, whereas no signal was detected on lymphocyte plasma membrane. 2. Treatment of mice with dexamethasone (Dex; 0.5-5 micrograms per mouse corresponding to approximately 0.015-1.5 mg kg-1) increased LC1 levels in neutrophils and monocytes. The 2-3 fold increase in LC1 levels was time-dependent with a peak at 2 h. Treatment of mice with the steroid antagonist, RU486 (two doses of 20 mg kg-1 orally) decreased LC1-like immunoreactivity in all three types of circulating leukocytes by > or = 50%. 3. Extravasation of blood neutrophils into inflamed tissue sites resulted in a consistent reduction (> or = 50%) in LC1 levels compared with circulating neutrophils. A high LC1-like immunoreactivity was also measured in resident macrophages, of which approximately one third was membrane-associated. Induction of an acute inflammatory response in the murine peritoneal cavity did not modify total LC1 levels measured in macrophages, but reduced membrane-associated LC1 to a significant extent, i.e. up to 70%. 4. In conclusion, flow cytometric analysis is a rapid and convenient method for detecting and measuring LC1 in murine leukocytes. We confirmed that LC1 protein expression is controlled by exogenous and endogenous glucocorticoids. Amongst other factor(s) influencing protein concentrations, extravasation was found to be associated with a reduced LC1 expression in the emigrated cells.

Tissue- and agonist-specific regulation of human and murine plasminogen activator inhibitor-1 promoters in transgenic mice.

PubMed

Eren, M; Painter, C A; Gleaves, L A; Schoenhard, J A; Atkinson, J B; Brown, N J; Vaughan, D E

2003-11-01

Numerous studies have described regulatory factors and sequences that control transcriptional responses in vitro. However, there is a paucity of information on the qualitative and quantitative regulation of heterologous promoters using transgenic strategies. In order to investigate the physiological regulation of human plasminogen activator inhibitor type-1 (hPAI-1) expression in vivo compared to murine PAI-1 (mPAI-1) and to test the physiological relevance of regulatory mechanisms described in vitro, we generated transgenic mice expressing enhanced green fluorescent protein (EGFP) driven by the proximal -2.9 kb of the hPAI-1 promoter. Transgenic animals were treated with Ang II, TGF-beta1 and lipopolysaccharide (LPS) to compare the relative activation of the human and murine PAI-1 promoters. Ang II increased EGFP expression most effectively in brain, kidney and spleen, while mPAI-1 expression was quantitatively enhanced most prominently in heart and spleen. TGF-beta1 failed to induce activation of the hPAI-1 promoter but potently stimulated mPAI-1 in kidney and spleen. LPS administration triggered robust expression of mPAI-1 in liver, kidney, pancreas, spleen and lung, while EGFP was induced only modestly in heart and kidney. These results indicate that the transcriptional response of the endogenous mPAI-1 promoter varies widely in terms of location and magnitude of response to specific stimuli. Moreover, the physiological regulation of PAI-1 expression likely involves a complex interaction of transcription factors and DNA sequences that are not adequately replicated by in vitro functional studies focused on the proximal -2.9 kb promoter.

Handling stress may confound murine gut microbiota studies.

PubMed

Allen-Blevins, Cary R; You, Xiaomeng; Hinde, Katie; Sela, David A

2017-01-01

Accumulating evidence indicates interactions between human milk composition, particularly sugars (human milk oligosaccharides or HMO), the gut microbiota of human infants, and behavioral effects. Some HMO secreted in human milk are unable to be endogenously digested by the human infant but are able to be metabolized by certain species of gut microbiota, including Bifidobacterium longum subsp. infantis (B. infantis) , a species sensitive to host stress (Bailey & Coe, 2004). Exposure to gut bacteria like B. infantis during critical neurodevelopment windows in early life appears to have behavioral consequences; however, environmental, physical, and social stress during this period can also have behavioral and microbial consequences. While rodent models are a useful method for determining causal relationships between HMO, gut microbiota, and behavior, murine studies of gut microbiota usually employ oral gavage, a technique stressful to the mouse. Our aim was to develop a less-invasive technique for HMO administration to remove the potential confound of gavage stress. Under the hypothesis that stress affects gut microbiota, particularly B. infantis , we predicted the pups receiving a prebiotic solution in a less-invasive manner would have the highest amount of Bifidobacteria in their gut. This study was designed to test two methods, active and passive, of solution administration to mice and the effects on their gut microbiome. Neonatal C57BL/6J mice housed in a specific-pathogen free facility received increasing doses of fructooligosaccharide (FOS) solution or deionized, distilled water. Gastrointestinal (GI) tracts were collected from five dams, six sires, and 41 pups over four time points. Seven fecal pellets from unhandled pups and two pellets from unhandled dams were also collected. Qualitative real-time polymerase chain reaction (qRT-PCR) was used to quantify and compare the amount of Bifidobacterium , Bacteroides , Bacteroidetes, and Firmicutes. Our results

Purification and protein composition of endogenous rat viruses.

PubMed

Hlubinová, K; Prachar, J; Vrbenská, A; Matoska, J; Simkovic, D

1984-01-01

Endogenous retroviruses are not in the majority of cases the cause of any neoplasia, except for the laboratory conditions. As far as they might serve for the evolution of pathogenic retroviruses more attention should have been paid to them. In this paper we introduce some approaches to the purification of rat endogenous retroviruses to such a degree of purity that enabled satisfactory SDS-PAGE analysis of its structural proteins. Purities of samples obtained by usual purification methods, long-term isopycnic centrifugation at a high gravity force and velocity centrifugation are compared. Protein profile of rat endogenous virus in SDS-PAGE is compared with the ones of other retroviruses. For the first time the evidence was obtained for the striking similarity between electrophoretic protein profile of rat endogenous virus WERC and feline leukemia virus. The major structural proteins of rat endogenous retrovirus and feline leukemia virus cannot be distinguished even when resolution long gradient PAGE had been employed. The accordance of electrophoretic mobilities of major structural proteins in SDS-PAGE can indicate the relatedness of retroviruses.

Endogenous galectin-3 expression levels modulate immune responses in galectin-3 transgenic mice.

PubMed

Chaudhari, Aparna D; Gude, Rajiv P; Kalraiya, Rajiv D; Chiplunkar, Shubhada V

2015-12-01

Galectin-3 (Gal-3), a β-galactoside-binding mammalian lectin, is involved in cancer progression and metastasis. However, there is an unmet need to identify the underlying mechanisms of cancer metastasis mediated by endogenous host galectin-3. Galectin-3 is also known to be an important regulator of immune responses. The present study was aimed at analysing how expression of endogenous galectin-3 regulates host immunity and lung metastasis in B16F10 murine melanoma model. Transgenic Gal-3(+/-) (hemizygous) and Gal-3(-/-) (null) mice exhibited decreased levels of Natural Killer (NK) cells and lower NK mediated cytotoxicity against YAC-1 tumor targets, compared to Gal-3(+/+) (wild-type) mice. On stimulation, Gal-3(+/-) and Gal-3(-/-) mice splenocytes showed increased T cell proliferation than Gal-3(+/+) mice. Intracellular calcium flux was found to be lower in activated T cells of Gal-3(-/-) mice as compared to T cells from Gal-3(+/+) and Gal-3(+/-) mice. In Gal-3(-/-) mice, serum Th1, Th2 and Th17 cytokine levels were found to be lowest, exhibiting dysregulation of pro-inflammatory and anti-inflammatory cytokines balance. Marked decrease in serum IFN-γ levels and splenic IFN-γR1 (IFN-γ Receptor 1) expressing T and NK cell percentages were observed in Gal-3(-/-) mice. On recombinant IFN-γ treatment of splenocytes in vitro, Suppressor of Cytokine Signaling (SOCS) 1 and SOCS3 protein expression was higher in Gal-3(-/-) mice compared to that in Gal-3(+/+) and Gal-3(+/-) mice; suggesting possible attenuation of Signal Transducer and Activator of Transcription (STAT) 1 mediated IFN-γ signaling in Gal-3(-/-) mice. The ability of B16F10 melanoma cells to form metastatic colonies in the lungs of Gal-3(+/+) and Gal-3(-/-) mice remained comparable, whereas it was found to be reduced in Gal-3(+/-) mice. Our data indicates that complete absence of endogenous host galectin-3 facilitates lung metastasis of B16F10 cells in mice, which may be contributed by dysregulated immune

An MRM-based workflow for quantifying cardiac mitochondrial protein phosphorylation in murine and human tissue.

PubMed

Lam, Maggie P Y; Scruggs, Sarah B; Kim, Tae-Young; Zong, Chenggong; Lau, Edward; Wang, Ding; Ryan, Christopher M; Faull, Kym F; Ping, Peipei

2012-08-03

The regulation of mitochondrial function is essential for cardiomyocyte adaptation to cellular stress. While it has long been understood that phosphorylation regulates flux through metabolic pathways, novel phosphorylation sites are continually being discovered in all functionally distinct areas of the mitochondrial proteome. Extracting biologically meaningful information from these phosphorylation sites requires an adaptable, sensitive, specific and robust method for their quantification. Here we report a multiple reaction monitoring-based mass spectrometric workflow for quantifying site-specific phosphorylation of mitochondrial proteins. Specifically, chromatographic and mass spectrometric conditions for 68 transitions derived from 23 murine and human phosphopeptides, and their corresponding unmodified peptides, were optimized. These methods enabled the quantification of endogenous phosphopeptides from the outer mitochondrial membrane protein VDAC, and the inner membrane proteins ANT and ETC complexes I, III and V. The development of this quantitative workflow is a pivotal step for advancing our knowledge and understanding of the regulatory effects of mitochondrial protein phosphorylation in cardiac physiology and pathophysiology. This article is part of a Special Issue entitled: Translational Proteomics. Copyright © 2012 Elsevier B.V. All rights reserved.

Nitrergic signalling via interstitial cells of Cajal regulates motor activity in murine colon.

PubMed

Lies, Barbara; Beck, Katharina; Keppler, Jonas; Saur, Dieter; Groneberg, Dieter; Friebe, Andreas

2015-10-15

In the enteric nervous systems, NO is released from nitrergic neurons as a major inhibitory neurotransmitter. NO acts via NO-sensitive guanylyl cyclase (NO-GC), which is found in different gastrointestinal (GI) cell types including smooth muscle cells (SMCs) and interstitial cells of Cajal (ICC). The precise mechanism of nitrergic signalling through these two cell types to regulate colonic spontaneous contractions is not fully understood yet. In the present study we investigated the impact of endogenous and exogenous NO on colonic contractile motor activity using mice lacking nitric oxide-sensitive guanylyl cyclase (NO-GC) globally and specifically in SMCs and ICC. Longitudinal smooth muscle of proximal colon from wild-type (WT) and knockout (KO) mouse strains exhibited spontaneous contractile activity ex vivo. WT and smooth muscle-specific guanylyl cyclase knockout (SMC-GCKO) colon showed an arrhythmic contractile activity with varying amplitudes and frequencies. In contrast, colon from global and ICC-specific guanylyl cyclase knockout (ICC-GCKO) animals showed a regular contractile rhythm with constant duration and amplitude of the rhythmic contractions. Nerve blockade (tetrodotoxin) or specific blockade of NO signalling (L-NAME, ODQ) did not significantly affect contractions of GCKO and ICC-GCKO colon whereas the arrhythmic contractile patterns of WT and SMC-GCKO colon were transformed into uniform motor patterns. In contrast, the response to electric field-stimulated neuronal NO release was similar in SMC-GCKO and global GCKO. In conclusion, our results indicate that basal enteric NO release acts via myenteric ICC to influence the generation of spontaneous contractions whereas the effects of elevated endogenous NO are mediated by SMCs in the murine proximal colon. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Analgesic effect of the neuropeptide cortistatin in murine models of arthritic inflammatory pain.

PubMed

Morell, Maria; Souza-Moreira, Luciana; Caro, Marta; O'Valle, Francisco; Forte-Lago, Irene; de Lecea, Luis; Gonzalez-Rey, Elena; Delgado, Mario

2013-05-01

To investigate the role of the antiinflammatory neuropeptide cortistatin in chronic pain evoked by joint inflammation. Thermal and mechanical hyperalgesia was evoked in mouse knee joints by intraplantar injection of tumor necrosis factor α and intraarticular infusion of Freund's complete adjuvant, and the analgesic effects of cortistatin, administered centrally, peripherally, and systemically, were assessed. In addition, the effects of cortistatin on the production of nociceptive peptides and the activation of pain signaling were assayed in dorsal root ganglion cultures and in inflammatory pain models. The role of endogenous cortistatin in pain sensitization and perpetuation of chronic inflammatory states was evaluated in cortistatin-deficient mice. Finally, the effect of noxious/inflammatory stimuli in the production of cortistatin by the peripheral nociceptive system was assayed in vitro and in vivo. Expression of cortistatin was observed in peptidergic nociceptors of the peripheral nociceptive system, and endogenous cortistatin was found to participate in the tuning of pain sensitization, especially in pathologic inflammatory conditions. Results showed that cortistatin acted both peripherally and centrally to reduce the tactile allodynia and heat hyperalgesia evoked by arthritis and peripheral tissue inflammation in mice, via mechanisms that were independent of its antiinflammatory action. These mechanisms involved direct action on nociceptive neurons and regulation of central sensitization. The analgesic effects of cortistatin in murine arthritic pain were linked to binding of the neuropeptide to somatostatin and ghrelin receptors, activation of the G protein subunit Gαi , impairment of ERK signaling, and decreased production of calcitonin gene-related peptide in primary nociceptors. These findings indicate that cortistatin is an antiinflammatory factor with potent analgesic effects that may offer a new approach to pain therapy in pathologic inflammatory

The tetravalent organic cation spermine causes the gating of the IRK1 channel expressed in murine fibroblast cells.

PubMed Central

Ishihara, K; Hiraoka, M; Ochi, R

1996-01-01

1. The activation kinetics of the IRK1 channel stably expressed in L cells (a murine fibroblast cell line) were studied under the whole-cell voltage clamp. Without polyamines or Mg2+ in the pipettes, inward currents showed an exponential activation on hyperpolarization. The steep inward rectification of the currents around the reversal potential (Erev) could be described by the open-close transition of the channel with first-order kinetics. 2. When the tetravalent organic cation spermine (Spm) was added in the pipettes, the activation kinetics changed; this was explicable by the increase in the closing rate constant. The activation of the currents observed without Spm or Mg2+ in the pipettes was ascribed to the unblocking of the 'endogenous-Spm block'. 3. In the presence of the divalent cation putrescine (Put) or of Mg2+ in the pipettes, a different non-conductive state suppressed the outward currents on depolarization; the channels instantaneously changed to the open state on repolarization. As the depolarization was prolonged, this non-conductive state was replaced by the non-conductive state that shows an exponential activation on repolarization. This phenomenon was attributed to the redistribution of the channels from the Put- or Mg(2+)-blocked state to the 'endogenous Spm-blocked state' during depolarization. 4. In the presence of the trivalent cation spermidine (Spd) in the pipettes, two different non-conductive states occurred, showing a faster and a slower activation on repolarization. The rectification around Erev was mainly due to the non-conductive state showing a faster activation, which appeared to be the Spd-blocked state. During depolarization, redistribution of the channels to the 'endogenous Spm-blocked state' also occurred. 5. In the presence of Spd, Put or Mg2+ in the pipettes, the voltage dependence of the activation time constant reflecting the unblocking of the 'endogenous Spm' was shifted in the hyperpolarizing direction. 6. Our results

Analysis of cardiomyocyte movement in the developing murine heart

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

Hashimoto, Hisayuki; Yuasa, Shinsuke, E-mail: yuasa@a8.keio.jp; Tabata, Hidenori

The precise assemblage of several types of cardiac precursors controls heart organogenesis. The cardiac precursors show dynamic movement during early development and then form the complicated heart structure. However, cardiomyocyte movements inside the newly organized mammalian heart remain unclear. We previously established the method of ex vivo time-lapse imaging of the murine heart to study cardiomyocyte behavior by using the Fucci (fluorescent ubiquitination-based cell cycle indicator) system, which can effectively label individual G1, S/G2/M, and G1/S-transition phase nuclei in living cardiomyocytes as red, green, and yellow, respectively. Global analysis of gene expression in Fucci green positive ventricular cardiomyocytes confirmed that cellmore » cycle regulatory genes expressed in G1/S, S, G2/M, and M phase transitions were upregulated. Interestingly, pathway analysis revealed that many genes related to the cell cycle were significantly upregulated in the Fucci green positive ventricular cardiomyocytes, while only a small number of genes related to cell motility were upregulated. Time-lapse imaging showed that murine proliferating cardiomyocytes did not exhibit dynamic movement inside the heart, but stayed on site after entering the cell cycle. - Highlights: • We directly visualized cardiomyocyte movement inside the developing murine heart. • Cell cycle related genes were upregulated in the proliferating cardiomyocytes. • Time-lapse imaging revealed that proliferating murine cardiomyocytes stayed in place. • Murine ventricular cardiomyocytes proliferate on site during development.« less

Explaining Cigarette Smoking: An Endogenous-Exogenous Analysis.

ERIC Educational Resources Information Center

McKillip, Jack

Kruglanski's endogenous-exogenous partition, when applied to reasons given by smokers for smoking cigarettes, distinguishes two types of actions: (1) endogenous reasons implying that the behavior of consuming the cigarette is the goal of the action and the actor is positive toward the behavior, and (2) exogenous reasons implying that the behavior…

Lack of endogenous parathyroid hormone delays fracture healing by inhibiting vascular endothelial growth factor‑mediated angiogenesis.

PubMed

Ding, Qingfeng; Sun, Peng; Zhou, Hao; Wan, Bowen; Yin, Jian; Huang, Yao; Li, Qingqing; Yin, Guoyong; Fan, Jin

2018-07-01

Intermittent low‑dose injections of parathyroid hormone (PTH) have been reported to exert bone anabolic effects and to promote fracture healing. As an important proangiogenic cytokine, vascular endothelial growth factor (VEGF) is secreted by bone marrow mesenchymal stem cells (BMSCs) and osteoblasts, and serves a crucial regulatory role in the process of vascular development and regeneration. To investigate whether lack of endogenous PTH causes reduced angiogenic capacity and thereby delays the process of fracture healing by downregulating the VEGF signaling pathway, a PTH knockout (PTHKO) mouse fracture model was generated. Fracture healing was observed using X‑ray and micro‑computerized tomography. Bone anabolic and angiogenic markers were analyzed by immunohistochemistry and western blot analysis. The expression levels of VEGF and associated signaling pathways in murine BMSC‑derived osteoblasts were measured by quantitative polymerase chain reaction and western blot analysis. The expression levels of protein kinase A (PKA), phosphorylated‑serine/threonine protein kinase (pAKT), hypoxia‑inducible factor‑1α (HIF1α) and VEGF were significantly decreased in BMSC‑derived osteoblasts from PTHKO mice. In addition, positive platelet endothelial cell adhesion molecule staining was reduced in PTHKO mice, as determined by immunohistochemistry. The expression levels of HIF1α, VEGF, runt‑related transcription factor 2, osteocalcin and alkaline phosphatase were also decreased in PTHKO mice, and fracture healing was delayed. In conclusion, lack of endogenous PTH may reduce VEGF expression in BMSC‑derived osteoblasts by downregulating the activity of the PKA/pAKT/HIF1α/VEGF pathway, thus affecting endochondral bone formation by causing a reduction in angiogenesis and osteogenesis, ultimately leading to delayed fracture healing.

Harnessing endogenous miR-181a to segregate transgenic antigen receptor expression in developing versus post-thymic T cells in murine hematopoietic chimeras.

PubMed

Papapetrou, Eirini P; Kovalovsky, Damian; Beloeil, Laurent; Sant'angelo, Derek; Sadelain, Michel

2009-01-01

MicroRNAs (miRNAs) are small, noncoding RNAs that regulate gene expression by targeting complementary sequences, referred to as miRNA recognition elements (MREs), typically located in the 3' untranslated region of mRNAs. miR-181a is highly expressed in developing thymocytes and markedly downregulated in post-thymic T cells. We investigated whether endogenous miR-181a can be harnessed to segregate expression of chimeric antigen receptors (CARs) and TCRs between developing and mature T cells. Lentiviral-encoded antigen receptors were tagged with a miR-181a-specific MRE and transduced into mouse BM cells that were used to generate hematopoietic chimeras. Expression of a CAR specific for human CD19 (hCD19) was selectively suppressed in late double-negative and double-positive thymocytes, coinciding with the peak in endogenous miR-181a expression. Receptor expression was fully restored in post-thymic resting and activated T cells, affording protection against a subsequent challenge with hCD19+ tumors. Hematopoietic mouse chimeras engrafted with a conalbumin-specific TCR prone to thymic clonal deletion acquired peptide-specific T cell responsiveness only when the vector-encoded TCR transcript was similarly engineered to be subject to regulation by miR-181a. These results demonstrate the potential of miRNA-regulated transgene expression in stem cell-based therapies, including cancer immunotherapy.

Endogenous lipoid pneumonia associated with Legionella pneumophila serogroup 1.

PubMed

Hui, Chee-Kin

2013-03-01

Endogenous lipoid pneumonia is an uncommon condition. This is a report of a 29-year-old woman diagnosed with endogenous lipoid pneumonia associated with Legionella pneumophila serogroup 1 infection. The patient's endogenous lipoid pneumonia resolved completely after treatment for Legionella pneumophila infection. This suggests that early diagnosis and aggressive treatment of the underlying infection may prevent any long-term sequelae of lipoid pneumonia.

Endogenous opiates and behavior: 2014.

PubMed

Bodnar, Richard J

2016-01-01

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular

The Increased Endogenous Sulfur Dioxide Acts as a Compensatory Mechanism for the Downregulated Endogenous Hydrogen Sulfide Pathway in the Endothelial Cell Inflammation

PubMed Central

Zhang, Da; Wang, Xiuli; Tian, Xiaoyu; Zhang, Lulu; Yang, Guosheng; Tao, Yinghong; Liang, Chen; Li, Kun; Yu, Xiaoqi; Tang, Xinjing; Tang, Chaoshu; Zhou, Jing; Kong, Wei; Du, Junbao; Huang, Yaqian; Jin, Hongfang

2018-01-01

Endogenous hydrogen sulfide (H2S) and sulfur dioxide (SO2) are regarded as important regulators to control endothelial cell function and protect endothelial cell against various injuries. In our present study, we aimed to investigate the effect of endogenous H2S on the SO2 generation in the endothelial cells and explore its significance in the endothelial inflammation in vitro and in vivo. The human umbilical vein endothelial cell (HUVEC) line (EA.hy926), primary HUVECs, primary rat pulmonary artery endothelial cells (RPAECs), and purified aspartate aminotransferase (AAT) protein from pig heart were used for in vitro experiments. A rat model of monocrotaline (MCT)-induced pulmonary vascular inflammation was used for in vivo experiments. We found that endogenous H2S deficiency caused by cystathionine-γ-lyase (CSE) knockdown increased endogenous SO2 level in endothelial cells and enhanced the enzymatic activity of AAT, a major SO2 synthesis enzyme, without affecting the expressions of AAT1 and AAT2. While H2S donor could reverse the CSE knockdown-induced increase in the endogenous SO2 level and AAT activity. Moreover, H2S donor directly inhibited the activity of purified AAT protein, which was reversed by a thiol reductant DTT. Mechanistically, H2S donor sulfhydrated the purified AAT1/2 protein and rescued the decrease in the sulfhydration of AAT1/2 protein in the CSE knockdown endothelial cells. Furthermore, an AAT inhibitor l-aspartate-β-hydroxamate (HDX), which blocked the upregulation of endogenous SO2/AAT generation induced by CSE knockdown, aggravated CSE knockdown-activated nuclear factor-κB pathway in the endothelial cells and its downstream inflammatory factors including ICAM-1, TNF-α, and IL-6. In in vivo experiment, H2S donor restored the deficiency of endogenous H2S production induced by MCT, and reversed the upregulation of endogenous SO2/AAT pathway via sulfhydrating AAT1 and AAT2. In accordance with the results of the in vitro experiment, HDX

[The endogenous opioid system and drug addiction].

PubMed

Maldonado, R

2010-01-01

Drug addiction is a chronic brain disorder leading to complex adaptive changes within the brain reward circuits. Several neurotransmitters, including the endogenous opioid system are involved in these changes. The opioid system plays a pivotal role in different aspects of addiction. Thus, opioid receptors and endogenous opioid peptides are largely distributed in the mesolimbic system and modulate dopaminergic activity within the reward circuits. Opioid receptors and peptides are selectively involved in several components of the addictive processes induced by opioids, cannabinoids, psychostimulants, alcohol and nicotine. This review is focused on the contribution of each component of the endogenous opioid system in the addictive properties of the different drugs of abuse. Copyright 2010 Elsevier Masson SAS. All rights reserved.

Endogenous versus Exogenous Origins of Crises

NASA Astrophysics Data System (ADS)

Sornette, Didier

Are large biological extinctions such as the Cretaceous/Tertiary KT boundary due to a meteorite, extreme volcanic activity or self-organized critical extinction cascades? Are commercial successes due to a progressive reputation cascade or the result of a well orchestrated advertisement? Determining the chain of causality for Xevents in complex systems requires disentangling interwoven exogenous and endogenous contributions with either no clear signature or too many signatures. Here, I review several efforts carried out with collaborators which suggest a general strategy for understanding the organizations of several complex systems under the dual effect of endogenous and exogenous fluctuations. The studied examples are: internet download shocks, book sale shocks, social shocks, financial volatility shocks, and financial crashes. Simple models are offered to quantitatively relate the endogenous organization to the exogenous response of the system. Suggestions for applications of these ideas to many other systems are offered.

Optimized endogenous post-stratification in forest inventories

Treesearch

Paul L. Patterson

2012-01-01

An example of endogenous post-stratification is the use of remote sensing data with a sample of ground data to build a logistic regression model to predict the probability that a plot is forested and using the predicted probabilities to form categories for post-stratification. An optimized endogenous post-stratified estimator of the proportion of forest has been...

Endogenous opioids regulate moment-to-moment neuronal communication and excitability.

PubMed

Winters, Bryony L; Gregoriou, Gabrielle C; Kissiwaa, Sarah A; Wells, Oliver A; Medagoda, Danashi I; Hermes, Sam M; Burford, Neil T; Alt, Andrew; Aicher, Sue A; Bagley, Elena E

2017-03-22

Fear and emotional learning are modulated by endogenous opioids but the cellular basis for this is unknown. The intercalated cells (ITCs) gate amygdala output and thus regulate the fear response. Here we find endogenous opioids are released by synaptic stimulation to act via two distinct mechanisms within the main ITC cluster. Endogenously released opioids inhibit glutamate release through the δ-opioid receptor (DOR), an effect potentiated by a DOR-positive allosteric modulator. Postsynaptically, the opioids activate a potassium conductance through the μ-opioid receptor (MOR), suggesting for the first time that endogenously released opioids directly regulate neuronal excitability. Ultrastructural localization of endogenous ligands support these functional findings. This study demonstrates a new role for endogenously released opioids as neuromodulators engaged by synaptic activity to regulate moment-to-moment neuronal communication and excitability. These distinct actions through MOR and DOR may underlie the opposing effect of these receptor systems on anxiety and fear.

Exercise induced asthma and endogenous opioids.

PubMed Central

Gaillard, R C; Bachman, M; Rochat, T; Egger, D; de Haller, R; Junod, A F

1986-01-01

Concentrations of endogenous opioid peptides in the plasma are increased during exercise and these substances have been implicated in the pathogenesis of asthma induced by chloropropramide and alcohol in diabetic patients. This work was undertaken to determine whether exercise induced asthma might be mediated by endogenous opioids. Plasma beta endorphin, met-enkephalin, and adrenocorticotrophic hormone (ACTH) concentrations were measured in five asthmatic patients and five normal volunteers breathing cold air during exercise. In four of the patients the effect of an infusion of naloxone on FEV1 was also measured during exercise induced asthma. Exercise produced acute bronchoconstriction in all asthmatics, characterised by a fall in FEV1; whereas no change occurred in normal subjects. There was no difference in plasma met-enkephalin, beta endorphin, and ACTH concentration between the two groups. Infusion of naloxone neither prevented nor worsened exercise induced asthma. These data suggest that endogenous opioids probably do not play a part in the development of exercise induced asthma. PMID:2944240

Soluble activin receptor type IIB decoy receptor differentially impacts murine osteogenesis imperfecta muscle function.

PubMed

Jeong, Youngjae; Daghlas, Salah A; Kahveci, Alp S; Salamango, Daniel; Gentry, Bettina A; Brown, Marybeth; Rector, R Scott; Pearsall, R Scott; Phillips, Charlotte L

2018-02-01

Osteogenesis imperfecta (OI) is characterized by skeletal fragility and muscle weakness. In this study we investigated the effects of soluble activin type IIB receptor (sActRIIB-mFc) on muscle mass and function in 2 distinct mouse models of OI: osteogenesis imperfecta murine (oim) and +/G610C. Wild-type (WT), +/G610C, and oim/oim mice were treated from 2 to 4 months of age with Tris-buffered saline (vehicle) or sActRIIB-mFc and their hindlimb muscles evaluated for mass, morphology, and contractile function. sActRIIB-mFc-treated WT, +/G610C, and oim/oim mice had increased hindlimb muscle weights and myofiber cross-sectional area compared with vehicle-treated counterparts. sActRIIB-mFc-treated oim/oim mice also exhibited increased contractile function relative to vehicle-treated counterparts. Blocking endogenous ActRIIB was effective at increasing muscle size in mouse models of OI, and increasing contractile function in oim/oim mice. ActRIIB inhibitors may provide a potential mutation-specific therapeutic option for compromised muscle function in OI. Muscle Nerve 57: 294-304, 2018. © 2017 Wiley Periodicals, Inc.

Endogenous Cortical Oscillations Constrain Neuromodulation by Weak Electric Fields

PubMed Central

Schmidt, Stephen L.; Iyengar, Apoorva K.; Foulser, A. Alban; Boyle, Michael R.; Fröhlich, Flavio

2014-01-01

Background Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation modality that may modulate cognition by enhancing endogenous neocortical oscillations with the application of sine-wave electric fields. Yet, the role of endogenous network activity in enabling and shaping the effects of tACS has remained unclear. Objective We combined optogenetic stimulation and multichannel slice electrophysiology to elucidate how the effect of weak sine-wave electric field depends on the ongoing cortical oscillatory activity. We hypothesized that the structure of the response to stimulation depended on matching the stimulation frequency to the endogenous cortical oscillation. Methods We studied the effect of weak sine-wave electric fields on oscillatory activity in mouse neocortical slices. Optogenetic control of the network activity enabled the generation of in vivo like cortical oscillations for studying the temporal relationship between network activity and sine-wave electric field stimulation. Results Weak electric fields enhanced endogenous oscillations but failed to induce a frequency shift of the ongoing oscillation for stimulation frequencies that were not matched to the endogenous oscillation. This constraint on the effect of electric field stimulation imposed by endogenous network dynamics was limited to the case of weak electric fields targeting in vivo-like network dynamics. Together, these results suggest that the key mechanism of tACS may be enhancing but not overriding of intrinsic network dynamics. Conclusion Our results contribute to understanding the inconsistent tACS results from human studies and propose that stimulation precisely adjusted in frequency to the endogenous oscillations is key to rational design of non-invasive brain stimulation paradigms. PMID:25129402

Telomere sister chromatid exchange in telomerase deficient murine cells.

PubMed

Wang, Yisong; Giannone, Richard J; Liu, Yie

2005-10-01

We have recently demonstrated that several types of genomic rearrangements (i.e., telomere sister chromatid exchange (T-SCE), genomic-SCE, or end-to-end fusions) were more often detected in long-term cultured murine telomerase deficient embryonic stem (ES) cells than in freshly prepared murine splenocytes, even through they possessed similar frequencies of critically short telomeres. The high rate of genomic rearrangements in telomerase deficient ES cells, when compared to murine splenocytes, may reflect the cultured cells' gained ability to protect chromosome ends with eroded telomeres allowing them to escape "end crisis". However, the possibility that ES cells were more permissive to genomic rearrangements than other cell types or that differences in the microenvironment or genetic background of the animals might consequentially determine the rate of T-SCEs or other genomic rearrangements at critically short telomeres could not be ruled out.

CoVaccine HT™ adjuvant is superior to Freund's adjuvants in eliciting antibodies against the endogenous alarmin HMGB1.

PubMed

Lakhan, Nerissa; Stevens, Natalie E; Diener, Kerrilyn R; Hayball, John D

2016-12-01

Adjuvants are used to enhance the immune response against specific antigens for the production of antibodies, with the choice of adjuvant most critical for poorly immunogenic and self-antigens. This study quantitatively and qualitatively evaluated CoVaccine HT™ and Freund's adjuvants for eliciting therapeutic ovine polyclonal antibodies targeting the endogenous alarmin, high mobility group box-1 (HMGB1). Sheep were immunised with HMGB1 protein in CoVaccine HT™ or Freund's adjuvants, with injection site reactions and antibody titres periodically assessed. The binding affinity of antibodies for HMGB1 and their neutralisation activity was determined in-vitro, with in vivo activity confirmed using a murine model of endotoxemia. Results indicated that CoVaccine HT™ elicited significantly higher antibody tires with stronger affinity and more functional potency than antibodies induced with Freund's adjuvants. These studies provide evidence that CoVaccine HT™ is superior to Freund's adjuvants for the production of antibodies to antigens with low immunogenicity and supports the use of this alternative adjuvant for clinical and experimental use antibodies. Copyright © 2016 Elsevier B.V. All rights reserved.

Intravenous anesthetic propofol suppresses prostaglandin E2 production in murine dendritic cells.

PubMed

Inada, Takefumi; Kubo, Kozue; Ueshima, Hironobu; Shingu, Koh

2011-01-01

Propofol is an intravenous anesthetic that is widely used for anesthesia and sedation. Dendritic cells (DC) are one of the crucial immune cells that bridge innate and adaptive immunity, in which DC process antigens during innate immune responses to present them to naïve T-cells, leading to an establishment of adaptive immunity. Prostaglandin (PG)-E(2) may be secreted by DC into the microenvironment, considerably influencing DC phenotype and function, and thus determining the fate of adaptive immunity. Since propofol suppresses PGE(2) production in murine macrophages, the primary purpose of the present study was to determine whether propofol also suppresses PGE(2) production in DC. Assuming a positive finding of such suppression, we tested whether this also leads to alterations of interleukin (IL)-12 and IL-10 production and DC surface marker expression, both of which can be modulated by PGE(2). In bone marrow-derived DC, propofol significantly suppressed the PGE(2) production after lipopolysaccharide stimulation. Cyclo-oxygenase (COX) protein expression and arachidonic acid release were unaffected, while COX enzyme activity was significantly inhibited by propofol. The propofol-induced COX inhibition did not lead to the increased production of cysteinyl leukotrienes and leukotriene-B(4). Endogenous COX inhibition with propofol, as well as with the selective COX-2 inhibitor, NS-398, did not affect IL-12 and IL-10 production from DC. The surface expression of I-A(b) and CD40 on DC was not changed, while that of CD86 slightly increased, with both propofol and NS-398; expression of CD80 was not affected with propofol, but increased slightly with NS-398. Finally, endogenous COX inhibition with either propofol or NS-398 did not significantly affect the ability of DC to induce allogeneic T-cell proliferation. It is concluded that the intravenous anesthetic propofol suppresses COX enzyme activity in DC, with no consequences with respect to IL-12/IL-10 production and

Invasive fungal infections in endogenous Cushing's syndrome

PubMed Central

Scheffel, Rafael Selbach; Dora, José Miguel; Weinert, Letícia Schwerz; Aquino, Valério; Maia, Ana Luiza; Canani, Luis Henrique; Goldani, Luciano Z.

2010-01-01

Cushing's syndrome is a condition characterized by elevated cortisol levels that can result from either augmented endogenous production or exogenous administration of corticosteroids. The predisposition to fungal infections among patients with hypercortisolemia has been noted since Cushing's original description of the disease. We describe here a patient with endogenous Cushing's syndrome secondary to an adrenocortical carcinoma, who developed concomitant disseminated cryptococcosis and candidiasis in the course of his disease. PMID:24470886

[Formation of endogenous pyrogen by mononuclear phagocytes].

PubMed

Agasarov, L G; Sorokin, A V; Ukhanova, I K

1984-07-01

Production of endogenous pyrogen by human and rabbit blood monocytes in response to stimulation with agents of different origin was studied by inhibitory analysis under comparable conditions. Actinomycin D and cytochalasin B were applied. New evidence was obtained about an important role in the mechanism of activation of mononuclear phagocytes of initial interaction between a stimulating agent and the leukocyte membrane and of the biphasic process of endogenous pyrogen production.

The PINK1 p.I368N mutation affects protein stability and ubiquitin kinase activity.

PubMed

Ando, Maya; Fiesel, Fabienne C; Hudec, Roman; Caulfield, Thomas R; Ogaki, Kotaro; Górka-Skoczylas, Paulina; Koziorowski, Dariusz; Friedman, Andrzej; Chen, Li; Dawson, Valina L; Dawson, Ted M; Bu, Guojun; Ross, Owen A; Wszolek, Zbigniew K; Springer, Wolfdieter

2017-04-24

Mutations in PINK1 and PARKIN are the most common causes of recessive early-onset Parkinson's disease (EOPD). Together, the mitochondrial ubiquitin (Ub) kinase PINK1 and the cytosolic E3 Ub ligase PARKIN direct a complex regulated, sequential mitochondrial quality control. Thereby, damaged mitochondria are identified and targeted to degradation in order to prevent their accumulation and eventually cell death. Homozygous or compound heterozygous loss of either gene function disrupts this protective pathway, though at different steps and by distinct mechanisms. While structure and function of PARKIN variants have been well studied, PINK1 mutations remain poorly characterized, in particular under endogenous conditions. A better understanding of the exact molecular pathogenic mechanisms underlying the pathogenicity is crucial for rational drug design in the future. Here, we characterized the pathogenicity of the PINK1 p.I368N mutation on the clinical and genetic as well as on the structural and functional level in patients' fibroblasts and in cell-based, biochemical assays. Under endogenous conditions, PINK1 p.I368N is expressed, imported, and N-terminally processed in healthy mitochondria similar to PINK1 wild type (WT). Upon mitochondrial damage, however, full-length PINK1 p.I368N is not sufficiently stabilized on the outer mitochondrial membrane (OMM) resulting in loss of mitochondrial quality control. We found that binding of PINK1 p.I368N to the co-chaperone complex HSP90/CDC37 is reduced and stress-induced interaction with TOM40 of the mitochondrial protein import machinery is abolished. Analysis of a structural PINK1 p.I368N model additionally suggested impairments of Ub kinase activity as the ATP-binding pocket was found deformed and the substrate Ub was slightly misaligned within the active site of the kinase. Functional assays confirmed the lack of Ub kinase activity. Here we demonstrated that mutant PINK1 p.I368N can not be stabilized on the OMM upon

Loss of VPS13C Function in Autosomal-Recessive Parkinsonism Causes Mitochondrial Dysfunction and Increases PINK1/Parkin-Dependent Mitophagy

PubMed Central

Lesage, Suzanne; Drouet, Valérie; Majounie, Elisa; Deramecourt, Vincent; Jacoupy, Maxime; Nicolas, Aude; Cormier-Dequaire, Florence; Hassoun, Sidi Mohamed; Pujol, Claire; Ciura, Sorana; Erpapazoglou, Zoi; Usenko, Tatiana; Maurage, Claude-Alain; Sahbatou, Mourad; Liebau, Stefan; Ding, Jinhui; Bilgic, Basar; Emre, Murat; Erginel-Unaltuna, Nihan; Guven, Gamze; Tison, François; Tranchant, Christine; Vidailhet, Marie; Corvol, Jean-Christophe; Krack, Paul; Leutenegger, Anne-Louise; Nalls, Michael A.; Hernandez, Dena G.; Heutink, Peter; Gibbs, J. Raphael; Hardy, John; Wood, Nicholas W.; Gasser, Thomas; Durr, Alexandra; Deleuze, Jean-François; Tazir, Meriem; Destée, Alain; Lohmann, Ebba; Kabashi, Edor; Singleton, Andrew; Corti, Olga; Brice, Alexis; Lesage, Suzanne; Tison, François; Vidailhet, Marie; Corvol, Jean-Christophe; Agid, Yves; Anheim, Mathieu; Bonnet, Anne-Marie; Borg, Michel; Broussolle, Emmanuel; Damier, Philippe; Destée, Alain; Dürr, Alexandra; Durif, Franck; Krack, Paul; Klebe, Stephan; Lohmann, Ebba; Martinez, Maria; Pollak, Pierre; Rascol, Olivier; Tranchant, Christine; Vérin, Marc; Viallet, François; Brice, Alexis; Lesage, Suzanne; Majounie, Elisa; Tison, François; Vidailhet, Marie; Corvol, Jean Christophe; Nalls, Michael A.; Hernandez, Dena G.; Gibbs, J. Raphael; Dürr, Alexandra; Arepalli, Sampath; Barker, Roger A.; Ben-Shlomo, Yoav; Berg, Daniela; Bettella, Francesco; Bhatia, Kailash; de Bie, Rob M.A.; Biffi, Alessandro; Bloem, Bastiaan R.; Bochdanovits, Zoltan; Bonin, Michael; Lesage, Suzanne; Tison, François; Vidailhet, Marie; Corvol, Jean-Christophe; Agid, Yves; Anheim, Mathieu; Bonnet, Anne-Marie; Borg, Michel; Broussolle, Emmanuel; Damier, Philippe; Destée, Alain; Dürr, Alexandra; Durif, Franck; Krack, Paul; Klebe, Stephan; Lohmann, Ebba; Martinez, Maria; Pollak, Pierre; Rascol, Olivier; Tranchant, Christine; Vérin, Marc; Bras, Jose M.; Brockmann, Kathrin; Brooks, Janet; Burn, David J.; Charlesworth, Gavin; Chen, Honglei; Chinnery, Patrick F.; Chong, Sean; Clarke, Carl E.; Cookson, Mark R.; Counsell, Carl; Damier, Philippe; Dartigues, Jean-François; Deloukas, Panos; Deuschl, Günther; Dexter, David T.; van Dijk, Karin D.; Dillman, Allissa; Dong, Jing; Durif, Frank; Edkins, Sarah; Escott-Price, Valentina; Evans, Jonathan R.; Foltynie, Thomas; Gao, Jianjun; Gardner, Michelle; Goate, Alison; Gray, Emma; Guerreiro, Rita; Harris, Clare; van Hilten, Jacobus J.; Hofman, Albert; Hollenbeck, Albert; Holmans, Peter; Holton, Janice; Hu, Michèle; Huang, Xuemei; Huber, Heiko; Hudson, Gavin; Hunt, Sarah E.; Huttenlocher, Johanna; Illig, Thomas; Jónsson, Pálmi V.; Kilarski, Laura L.; Jansen, Iris E.; Lambert, Jean-Charles; Langford, Cordelia; Lees, Andrew; Lichtner, Peter; Limousin, Patricia; Lopez, Grisel; Lorenz, Delia; Lubbe, Steven; Lungu, Codrin; Martinez, María; Mätzler, Walter; McNeill, Alisdair; Moorby, Catriona; Moore, Matthew; Morrison, Karen E.; Mudanohwo, Ese; O’Sullivan, Sean S.; Owen, Michael J.; Pearson, Justin; Perlmutter, Joel S.; Pétursson, Hjörvar; Plagnol, Vincent; Pollak, Pierre; Post, Bart; Potter, Simon; Ravina, Bernard; Revesz, Tamas; Riess, Olaf; Rivadeneira, Fernando; Rizzu, Patrizia; Ryten, Mina; Saad, Mohamad; Simón-Sánchez, Javier; Sawcer, Stephen; Schapira, Anthony; Scheffer, Hans; Schulte, Claudia; Sharma, Manu; Shaw, Karen; Sheerin, Una-Marie; Shoulson, Ira; Shulman, Joshua; Sidransky, Ellen; Spencer, Chris C.A.; Stefánsson, Hreinn; Stefánsson, Kári; Stockton, Joanna D.; Strange, Amy; Talbot, Kevin; Tanner, Carlie M.; Tashakkori-Ghanbaria, Avazeh; Trabzuni, Daniah; Traynor, Bryan J.; Uitterlinden, André G.; Velseboer, Daan; Walker, Robert; van de Warrenburg, Bart; Wickremaratchi, Mirdhu; Williams-Gray, Caroline H.; Winder-Rhodes, Sophie; Wurster, Isabel; Williams, Nigel; Morris, Huw R.; Heutink, Peter; Hardy, John; Wood, Nicholas W.; Gasser, Thomas; Singleton, Andrew B.; Brice, Alexis

2016-01-01

Autosomal-recessive early-onset parkinsonism is clinically and genetically heterogeneous. The genetic causes of approximately 50% of autosomal-recessive early-onset forms of Parkinson disease (PD) remain to be elucidated. Homozygozity mapping and exome sequencing in 62 isolated individuals with early-onset parkinsonism and confirmed consanguinity followed by data mining in the exomes of 1,348 PD-affected individuals identified, in three isolated subjects, homozygous or compound heterozygous truncating mutations in vacuolar protein sorting 13C (VPS13C). VPS13C mutations are associated with a distinct form of early-onset parkinsonism characterized by rapid and severe disease progression and early cognitive decline; the pathological features were striking and reminiscent of diffuse Lewy body disease. In cell models, VPS13C partly localized to the outer membrane of mitochondria. Silencing of VPS13C was associated with lower mitochondrial membrane potential, mitochondrial fragmentation, increased respiration rates, exacerbated PINK1/Parkin-dependent mitophagy, and transcriptional upregulation of PARK2 in response to mitochondrial damage. This work suggests that loss of function of VPS13C is a cause of autosomal-recessive early-onset parkinsonism with a distinctive phenotype of rapid and severe progression. PMID:26942284

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

PubMed

Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Endogenous Retroviruses in the Genomics Era.

PubMed

Johnson, Welkin E

2015-11-01

Endogenous retroviruses comprise millions of discrete genetic loci distributed within the genomes of extant vertebrates. These sequences, which are clearly related to exogenous retroviruses, represent retroviral infections of the deep past, and their abundance suggests that retroviruses were a near-constant presence throughout the evolutionary history of modern vertebrates. Endogenous retroviruses contribute in myriad ways to the evolution of host genomes, as mutagens and as sources of genetic novelty (both coding and regulatory) to be acted upon by the twin engines of random genetic drift and natural selection. Importantly, the richness and complexity of endogenous retrovirus data can be used to understand how viruses spread and adapt on evolutionary timescales by combining population genetics and evolutionary theory with a detailed understanding of retrovirus biology (gleaned from the study of extant retroviruses). In addition to revealing the impact of viruses on organismal evolution, such studies can help us better understand, by looking back in time, how life-history traits, as well as ecological and geological events, influence the movement of viruses within and between populations.

Proteolysis Controls Endogenous Substance P Levels

PubMed Central

Mitchell, Andrew J.; Lone, Anna Mari; Tinoco, Arthur D.; Saghatelian, Alan

2013-01-01

Substance P (SP) is a prototypical neuropeptide with roles in pain and inflammation. Numerous mechanisms regulate endogenous SP levels, including the differential expression of SP mRNA and the controlled secretion of SP from neurons. Proteolysis has long been suspected to regulate extracellular SP concentrations but data in support of this hypothesis is scarce. Here, we provide evidence that proteolysis controls SP levels in the spinal cord. Using peptidomics to detect and quantify endogenous SP fragments, we identify the primary SP cleavage site as the C-terminal side of the ninth residue of SP. If blocking this pathway increases SP levels, then proteolysis controls SP concentration. We performed a targeted chemical screen using spinal cord lysates as a proxy for the endogenous metabolic environment and identified GM6001 (galardin, ilomastat) as a potent inhibitor of the SP 1–9-producing activity present in the tissue. Administration of GM6001 to mice results in a greater-than-three-fold increase in the spinal cord levels of SP, which validates the hypothesis that proteolysis controls physiological SP levels. PMID:23894327

Proteolysis controls endogenous substance P levels.

PubMed

Mitchell, Andrew J; Lone, Anna Mari; Tinoco, Arthur D; Saghatelian, Alan

2013-01-01

Substance P (SP) is a prototypical neuropeptide with roles in pain and inflammation. Numerous mechanisms regulate endogenous SP levels, including the differential expression of SP mRNA and the controlled secretion of SP from neurons. Proteolysis has long been suspected to regulate extracellular SP concentrations but data in support of this hypothesis is scarce. Here, we provide evidence that proteolysis controls SP levels in the spinal cord. Using peptidomics to detect and quantify endogenous SP fragments, we identify the primary SP cleavage site as the C-terminal side of the ninth residue of SP. If blocking this pathway increases SP levels, then proteolysis controls SP concentration. We performed a targeted chemical screen using spinal cord lysates as a proxy for the endogenous metabolic environment and identified GM6001 (galardin, ilomastat) as a potent inhibitor of the SP(1-9)-producing activity present in the tissue. Administration of GM6001 to mice results in a greater-than-three-fold increase in the spinal cord levels of SP, which validates the hypothesis that proteolysis controls physiological SP levels.

Telomere sister chromatid exchange in telomerase deficient murine cells

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

Wang, Yisong; Giannone, Richard J; Liu, Yie

2005-01-01

We have recently demonstrated that several types of genomic rearrangements (i.e., telomere sister chromatid exchange (T-SCE), genomic-SCE, or end-to-end fusions) were more often detected in long-term cultured murine telomerase deficient embryonic stem (ES) cells than in freshly prepared murine splenocytes, even through they possessed similar frequencies of critically short telomeres. The high rate of genomic rearrangements in telomerase deficient ES cells, when compared to murine splenocytes, may reflect the cultured cells' gained ability to protect chromosome ends with eroded telomeres allowing them to escape 'end crisis'. However, the possibility that ES cells were more permissive to genomic rearrangements than othermore » cell types or that differences in the microenvironment or genetic background of the animals might consequentially determine the rate of T-SCEs or other genomic rearrangements at critically short telomeres could not be ruled out.« less

The PINK1-PARKIN Mitochondrial Ubiquitylation Pathway Drives a Program of OPTN/NDP52 Recruitment and TBK1 Activation to Promote Mitophagy.

PubMed

Heo, Jin-Mi; Ordureau, Alban; Paulo, Joao A; Rinehart, Jesse; Harper, J Wade

2015-10-01

Damaged mitochondria are detrimental to cellular homeostasis. One mechanism for removal of damaged mitochondria involves the PINK1-PARKIN pathway, which poly-ubiquitylates damaged mitochondria to promote mitophagy. We report that assembly of ubiquitin chains on mitochondria triggers autophagy adaptor recruitment concomitantly with activation of the TBK1 kinase, which physically associates with OPTN, NDP52, and SQSTM1. TBK1 activation in HeLa cells requires OPTN and NDP52 and OPTN ubiquitin chain binding. In addition to the known role of S177 phosphorylation in OPTN on ATG8 recruitment, TBK1-dependent phosphorylation on S473 and S513 promotes ubiquitin chain binding in vitro as well as TBK1 activation, OPTN mitochondrial retention, and efficient mitophagy in vivo. These data reveal a self-reinforcing positive feedback mechanism that coordinates TBK1-dependent autophagy adaptor phosphorylation with the assembly of ubiquitin chains on mitochondria to facilitate efficient mitophagy, and mechanistically links genes mutated in Parkinson's disease and amyotrophic lateral sclerosis in a common selective autophagy pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

Alpha Power Modulates Perception Independently of Endogenous Factors.

PubMed

Brüers, Sasskia; VanRullen, Rufin

2018-01-01

Oscillations are ubiquitous in the brain. Alpha oscillations in particular have been proposed to play an important role in sensory perception. Past studies have shown that the power of ongoing EEG oscillations in the alpha band is negatively correlated with visual outcome. Moreover, it also co-varies with other endogenous factors such as attention, vigilance, or alertness. In turn, these endogenous factors influence visual perception. Therefore, it remains unclear how much of the relation between alpha and perception is indirectly mediated by such endogenous factors, and how much reflects a direct causal influence of alpha rhythms on sensory neural processing. We propose to disentangle the direct from the indirect causal routes by introducing modulations of alpha power, independently of any fluctuations in endogenous factors. To this end, we use white-noise sequences to constrain the brain activity of 20 participants. The cross-correlation between the white-noise sequences and the concurrently recorded EEG reveals the impulse response function (IRF), a model of the systematic relationship between stimulation and brain response. These IRFs are then used to reconstruct rather than record the brain activity linked with new random sequences (by convolution). Interestingly, this reconstructed EEG only contains information about oscillations directly linked to the white-noise stimulation; fluctuations in attention and other endogenous factors may still modulate brain alpha rhythms during the task, but our reconstructed EEG is immune to these factors. We found that the detection of near-perceptual threshold targets embedded within these new white-noise sequences depended on the power of the ~10 Hz reconstructed EEG over parieto-occipital channels. Around the time of presentation, higher power led to poorer performance. Thus, fluctuations in alpha power, induced here by random luminance sequences, can directly influence perception: the relation between alpha power and

Novel endogenous angiogenesis inhibitors and their therapeutic potential

PubMed Central

Rao, Nithya; Lee, Yu Fei; Ge, Ruowen

2015-01-01

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature is essential for embryonic development and tissue homeostasis. It also plays critical roles in diseases such as cancer and retinopathy. A delicate balance between pro- and anti-angiogenic factors ensures normal physiological homeostasis. Endogenous angiogenesis inhibitors are proteins or protein fragments that are formed in the body and have the ability to limit angiogenesis. Many endogenous angiogenesis inhibitors have been discovered, and the list continues to grow. Endogenous protein/peptide inhibitors are relatively less toxic, better tolerated and have a lower risk of drug resistance, which makes them attractive as drug candidates. In this review, we highlight ten novel endogenous protein angiogenesis inhibitors discovered within the last five years, including ISM1, FKBPL, CHIP, ARHGAP18, MMRN2, SOCS3, TAp73, ZNF24, GPR56 and JWA. Although some of these proteins have been well characterized for other biological functions, we focus on their new and specific roles in angiogenesis inhibition and discuss their potential for therapeutic application. PMID:26364800

Novel endogenous angiogenesis inhibitors and their therapeutic potential.

PubMed

Rao, Nithya; Lee, Yu Fei; Ge, Ruowen

2015-10-01

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature is essential for embryonic development and tissue homeostasis. It also plays critical roles in diseases such as cancer and retinopathy. A delicate balance between pro- and anti-angiogenic factors ensures normal physiological homeostasis. Endogenous angiogenesis inhibitors are proteins or protein fragments that are formed in the body and have the ability to limit angiogenesis. Many endogenous angiogenesis inhibitors have been discovered, and the list continues to grow. Endogenous protein/peptide inhibitors are relatively less toxic, better tolerated and have a lower risk of drug resistance, which makes them attractive as drug candidates. In this review, we highlight ten novel endogenous protein angiogenesis inhibitors discovered within the last five years, including ISM1, FKBPL, CHIP, ARHGAP18, MMRN2, SOCS3, TAp73, ZNF24, GPR56 and JWA. Although some of these proteins have been well characterized for other biological functions, we focus on their new and specific roles in angiogenesis inhibition and discuss their potential for therapeutic application.

Current Translational Research and Murine Models For Duchenne Muscular Dystrophy

PubMed Central

Rodrigues, Merryl; Echigoya, Yusuke; Fukada, So-ichiro; Yokota, Toshifumi

2016-01-01

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder characterized by progressive muscle degeneration. Mutations in the DMD gene result in the absence of dystrophin, a protein required for muscle strength and stability. Currently, there is no cure for DMD. Since murine models are relatively easy to genetically manipulate, cost effective, and easily reproducible due to their short generation time, they have helped to elucidate the pathobiology of dystrophin deficiency and to assess therapies for treating DMD. Recently, several murine models have been developed by our group and others to be more representative of the human DMD mutation types and phenotypes. For instance, mdx mice on a DBA/2 genetic background, developed by Fukada et al., have lower regenerative capacity and exhibit very severe phenotype. Cmah-deficient mdx mice display an accelerated disease onset and severe cardiac phenotype due to differences in glycosylation between humans and mice. Other novel murine models include mdx52, which harbors a deletion mutation in exon 52, a hot spot region in humans, and dystrophin/utrophin double-deficient (dko), which displays a severe dystrophic phenotype due the absence of utrophin, a dystrophin homolog. This paper reviews the pathological manifestations and recent therapeutic developments in murine models of DMD such as standard mdx (C57BL/10), mdx on C57BL/6 background (C57BL/6-mdx), mdx52, dystrophin/utrophin double-deficient (dko), mdxβgeo, Dmd-null, humanized DMD (hDMD), mdx on DBA/2 background (DBA/2-mdx), Cmah-mdx, and mdx/mTRKO murine models. PMID:27854202

Hypoxic adaptation engages the CBP/CREST-induced coactivator complex of Creb-HIF-1α in transactivating murine neuroblastic glucose transporter

PubMed Central

Thamotharan, Shanthie; Raychaudhuri, Nupur; Tomi, Masatoshi; Shin, Bo-Chul

2013-01-01

We have shown in vitro a hypoxia-induced time-dependent increase in facilitative glucose transporter isoform 3 (GLUT3) expression in N2A murine neuroblasts. This increase in GLUT3 expression is partially reliant on a transcriptional increase noted in actinomycin D and cycloheximide pretreatment experiments. Transient transfection assays in N2A neuroblasts using murine glut3-luciferase reporter constructs mapped the hypoxia-induced enhancer activities to −857- to −573-bp and −203- to −177-bp regions. Hypoxia-exposed N2A nuclear extracts demonstrated an increase in HIF-1α and p-Creb binding to HRE (−828 to −824 bp) and AP-1 (−187 to −180 bp) cis-elements, respectively, in electromobility shift and supershift assays, which was confirmed by chromatin immunoprecipitation assays. In addition, the interaction of CBP with Creb and HIF-1α and CREST with CBP in hypoxia was detected by coimmunoprecipitation. Furthermore, small interference (si)RNA targeting Creb in these cells decreased endogenous Creb concentrations that reduced by twofold hypoxia-induced glut3 gene transcription. Thus, in N2A neuroblasts, phosphorylated HIF-1α and Creb mediated the hypoxia-induced increase in glut3 transcription. Coactivation by the Ca++-dependent CREST and CBP proteins may enhance cross-talk between p-Creb-AP-1 and HIF-1α/HRE of the glut3 gene. Collectively, these processes can facilitate an adaptive response to hypoxic energy depletion targeted at enhancing glucose transport and minimizing injury while fueling the proliferative potential of neuroblasts. PMID:23321477

Differences between endogenous and exogenous emotion inhibition in the human brain.

PubMed

Kühn, Simone; Haggard, Patrick; Brass, Marcel

2014-05-01

The regulation of emotions is an integral part of our mental health. It has only recently been investigated using brain imaging techniques. In most studies, participants are instructed by a cue to inhibit a specific emotional reaction. The aim of the present study was to investigate the alternative situation where a person decides to inhibit an emotion as an act of endogenous self-control. Healthy participants viewed highly arousing pictures with negative valence. In the endogenous condition, participants could freely choose on each trial to inhibit or feel the emotions elicited by the picture. In an exogenous condition, a visual cue instructed them to either feel or inhibit the emotion elicited by the picture. Participants' subjective ratings of intensity of experienced emotion showed an interaction effect between source of control (endogenous/exogenous) and feel/inhibit based on a stronger modulation between feel and inhibition for the endogenous compared to the exogenous condition. Endogenous inhibition of emotions was associated with dorso-medial prefrontal cortex activation, whereas exogenous inhibition was found associated with lateral prefrontal cortex activation. Thus, the brain regions for both endogenous and exogenous inhibition of emotion are highly similar to those for inhibition of motor actions in Brass and Haggard (J Neurosci 27:9141-9145, 2007), Kühn et al. (Hum Brain Mapp 30:2834-2843, 2009). Functional connectivity analyses showed that dorsofrontomedial cortex exerts greater control onto pre-supplementary motor area during endogenous inhibition compared to endogenous feel. This functional dissociation between an endogenous, fronto-medial and an exogenous, fronto-lateral inhibition centre has important implications for our understanding of emotion regulation in health and psychopathology.

Exogenic and endogenic Europa minerals

NASA Astrophysics Data System (ADS)

Maynard-Casely, H. E.; Brand, H. E. A.; Wilson, S. A.

2016-12-01

The Galileo Near Infrared Mapping Spectrometer (NIMS) identified a significant `non-ice' component upon the surface of Jupiter's moon Europa. Current explanations invoke both endogenic and exogenic origins for this material. It has long been suggested that magnesium and sodium sulfate minerals could have leached from the rock below a putative ocean (endogenic) 1 and that sulfuric acid hydrate minerals could have been radiologically produced from ionised sulfur originally from Io's volcanoes (exogenic) 2. However, a more recent theory proposes that the `non-ice' component could be radiation damaged NaCl leached from Europa's speculative ocean 3. What if the minerals are actually from combination of both endogenic and exogenic sources? To investigate this possibility we have focused on discovering new minerals that might form in the combination of the latter two cases, that is a mixture of leached sulfates hydrates with radiologically produced sulfuric acid. To this end we have explored a number of solutions in the MgSO4-H2SO4-H2O and Na2SO4-H2SO4-H2O systems, between 80 and 280 K with synchrotron x-ray powder diffraction. We report a number of new materials formed in this these ternary systems. This suggests that it should be considered that the `non-ice' component of the Europa's surface could be a material derived from endogenic and exogenic components. 1 Kargel, J. S. Brine volcanism and the interior structures of asteroids and icy satellites. Icarus 94, 368-390 (1991). 2 Carlson, R. W., Anderson, M. S., Mehlman, R. & Johnson, R. E. Distribution of hydrate on Europa: Further evidence for sulfuric acid hydrate. Icarus 177, 461-471, doi:10.1016/j.icarus.2005.03.026 (2005). 3 Hand, K. P. & Carlson, R. W. Europa's surface color suggests an ocean rich with sodium chloride. Geophysical Research Letters, 2015GL063559, doi:10.1002/2015gl063559 (2015).

Convection enhanced delivery of carmustine to the murine brainstem: a feasibility study.

PubMed

Sewing, A Charlotte P; Caretti, Viola; Lagerweij, Tonny; Schellen, Pepijn; Jansen, Marc H A; van Vuurden, Dannis G; Idema, Sander; Molthoff, Carla F M; Vandertop, W Peter; Kaspers, Gertjan J L; Noske, David P; Hulleman, Esther

2014-12-30

Systemic delivery of therapeutic agents remains ineffective against diffuse intrinsic pontine glioma (DIPG), possibly due to an intact blood-brain-barrier (BBB) and to dose-limiting toxicity of systemic chemotherapeutic agents. Convection-enhanced delivery (CED) into the brainstem may provide an effective local delivery alternative for DIPG patients. The aim of this study is to develop a method to perform CED into the murine brainstem and to test this method using the chemotherapeutic agent carmustine (BiCNU). To this end, a newly designed murine CED catheter was tested in vitro and in vivo. After determination of safety and distribution, mice bearing VUMC-DIPG-3 and E98FM-DIPG brainstem tumors were treated with carmustine dissolved in DW 5% or carmustine dissolved in 10% ethanol. Our results show that CED into the murine brainstem is feasible and well tolerated by mice with and without brainstem tumors. CED of carmustine dissolved in 5% DW increased median survival of mice with VUMC-DIPG-3 and E98FM-DIPG tumors with 35% and 25% respectively. Dissolving carmustine in 10% ethanol further improved survival to 45% in mice with E98FM-DIPG tumors. Since genetically engineered and primary DIPG models are currently only available in mice, murine CED studies have clear advantages over CED studies in other animals. CED in the murine brainstem can be performed safely, is well tolerated and can be used to study efficacy of chemotherapeutic agents orthotopically. These results set the foundation for more CED studies in murine DIPG models. Copyright © 2014 Elsevier B.V. All rights reserved.

Drosophila PINK1 and parkin loss-of-function mutants display a range of non-motor Parkinson's disease phenotypes.

PubMed

Julienne, Hannah; Buhl, Edgar; Leslie, David S; Hodge, James J L

2017-08-01

Parkinson's disease (PD) is more commonly associated with its motor symptoms and the related degeneration of dopamine (DA) neurons. However, it is becoming increasingly clear that PD patients also display a wide range of non-motor symptoms, including memory deficits and disruptions of their sleep-wake cycles. These have a large impact on their quality of life, and often precede the onset of motor symptoms, but their etiology is poorly understood. The fruit fly Drosophila has already been successfully used to model PD, and has been used extensively to study relevant non-motor behaviours in other contexts, but little attention has yet been paid to modelling non-motor symptoms of PD in this genetically tractable organism. We examined memory performance and circadian rhythms in flies with loss-of-function mutations in two PD genes: PINK1 and parkin. We found learning and memory abnormalities in both mutant genotypes, as well as a weakening of circadian rhythms that is underpinned by electrophysiological changes in clock neurons. Our study paves the way for further work that may help us understand the mechanisms underlying these neglected aspects of PD, thus identifying new targets for treatments to address these non-motor problems specifically and perhaps even to halt disease progression in its prodromal phase. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Endogenous versus Exogenous Growth Factor Regulation of Articular Chondrocytes

PubMed Central

Shi, Shuiliang; Chan, Albert G.; Mercer, Scott; Eckert, George J.; Trippel, Stephen B.

2014-01-01

Anabolic growth factors that regulate the function of articular chondrocytes are candidates for articular cartilage repair. Such factors may be delivered by pharmacotherapy in the form of exogenous proteins, or by gene therapy as endogenous proteins. It is unknown whether delivery method influences growth factor effectiveness in regulating articular chondrocyte reparative functions. We treated adult bovine articular chondrocytes with exogenous recombinant insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-β1), or with the genes encoding these growth factors for endogenous production. Treatment effects were measured as change in chondrocyte DNA content, glycosaminoglycan production, and aggrecan gene expression. We found that IGF-I stimulated chondrocyte biosynthesis similarly when delivered by either exogenous or endogenous means. In contrast, exogenous TGF-ß1 stimulated these reparative functions, while endogenous TGF-ß1 had little effect. Endogenous TGF-ß1 became more bioactive following activation of the transgene protein product. These data indicate that effective mechanisms of growth factor delivery for articular cartilage repair may differ for different growth factors. In the case of IGF-I, gene therapy or protein therapy appear to be viable options. In contrast, TGF-ß1 gene therapy may be constrained by a limited ability of chondrocytes to convert latent complexes to an active form. PMID:24105960

Behavior of a cloned murine interferon alpha/beta receptor expressed in homospecific or heterospecific background.

PubMed

Uzé, G; Lutfalla, G; Bandu, M T; Proudhon, D; Mogensen, K E

1992-05-15

A murine interferon (IFN) alpha/beta receptor was cloned from the IFN-sensitive L1210 cell line on the basis of its homology with the human receptor. A combination of methods that includes the screening of random-primed and oligo(dT)-primed cDNA libraries and polymerase chain reactions with a single-side specificity was used. At the amino acid level, the murine IFN-alpha/beta shows 46% identity with its human counterpart. Both human WISH cells presenting a low sensitivity to mouse IFN and a murine L1210 mutant subline that does not express the receptor have been stably transfected with the murine IFN-alpha/beta receptor. Whereas transfected human cells became sensitive to a limited number of mouse IFN-alpha/beta subtypes, the transfected murine L1210 mutant was found to be fully complemented and became sensitive to all mouse IFN-alpha/beta subtypes tested, including those that were not active on transfected human cells. These results strongly suggest that the receptor described here is implicated in the mediation of the activities of all murine IFN-alpha/beta subtypes.

Vitamin E attenuates myocardial ischemia-reperfusion injury in murine AIDS.

PubMed

Chen, Yinhong; Davis-Gorman, Grace; Watson, Ronald Ross; McDonagh, Paul F

2002-01-01

The incidence of myocardial infarction in patients who have the aquired immunodeficiency syndrome (AIDS) is increasing. However, no effective therapeutic agents have been discovered to reduce myocardial ischemia-reperfusion (I/R) injury in pathologies associated with AIDS. The aim of this study was to determine if infarct size is increased in murine AIDS after I/R injury and if I/R injury could be attenuated with vitamin E supplementation. Three groups of mice were studied: control, murine AIDS, and murine AIDS with vitamin E supplementation. Anesthetized mice were subjected to 30 min of left anterior descending coronary artery occlusion and 120 min of reperfusion. The hearts in mice that had murine AIDS had a larger infarct size compared to controls after I/R injury. Vitamin E supplementation significantly reduced infarct size and inhibited polymorphonuclear neutrophil (PMN) CD11b expression (p < 0.05). However, vitamin E supplementation did not affect PMN reactive oxygen species (ROS) production and platelet CD62p expression. These results suggest that the reduction of myocardial I/R injury with vitamin E supplementation may be the result of the inhibition of PMN CD11b expression. Vitamin E may be a promising prophylactic agent for the reduction of the severity of myocardial I/R injury in patients who have AIDS.

Miniature Microwave Applicator for Murine Bladder Hyperthermia Studies

PubMed Central

Salahi, Sara; Maccarini, Paolo F.; Rodrigues, Dario B.; Etienne, Wiguins; Landon, Chelsea D.; Inman, Brant A.; Dewhirst, Mark W.; Stauffer, Paul R.

2012-01-01

Purpose Novel combinations of heat with chemotherapeutic agents are often studied in murine tumor models. Currently, no device exists to selectively heat small tumors at depth in mice. In this project, we modelled, built and tested a miniature microwave heat applicator, the physical dimensions of which can be scaled to adjust the volume and depth of heating to focus on the tumor volume. Of particular interest is a device that can selectively heat murine bladder. Materials and Methods Using Avizo® segmentation software, we created a numerical mouse model based on micro-MRI scan data. The model was imported into HFSS™ simulation software and parametric studies were performed to optimize the dimensions of a water-loaded circular waveguide for selective power deposition inside a 0.15ml bladder. A working prototype was constructed operating at 2.45GHz. Heating performance was characterized by mapping fiber-optic temperature sensors along catheters inserted at depths of 0-1mm (subcutaneous), 2-3mm (vaginal), and 4-5mm (rectal) below the abdominal wall, with the mid-depth catheter adjacent to the bladder. Core temperature was monitored orally. Results Thermal measurements confirm the simulations which demonstrate that this applicator can provide local heating at depth in small animals. Measured temperatures in murine pelvis show well-localized bladder heating to 42-43°C while maintaining normothermic skin and core temperatures. Conclusions Simulation techniques facilitate the design optimization of microwave antennas for use in pre-clinical applications such as localized tumor heating in small animals. Laboratory measurements demonstrate the effectiveness of a new miniature water-coupled microwave applicator for localized heating of murine bladder. PMID:22690856

Miniature microwave applicator for murine bladder hyperthermia studies.

PubMed

Salahi, Sara; Maccarini, Paolo F; Rodrigues, Dario B; Etienne, Wiguins; Landon, Chelsea D; Inman, Brant A; Dewhirst, Mark W; Stauffer, Paul R

2012-01-01

Novel combinations of heat with chemotherapeutic agents are often studied in murine tumour models. Currently, no device exists to selectively heat small tumours at depth in mice. In this project we modelled, built and tested a miniature microwave heat applicator, the physical dimensions of which can be scaled to adjust the volume and depth of heating to focus on the tumour volume. Of particular interest is a device that can selectively heat murine bladder. Using Avizo(®) segmentation software, we created a numerical mouse model based on micro-MRI scan data. The model was imported into HFSS™ (Ansys) simulation software and parametric studies were performed to optimise the dimensions of a water-loaded circular waveguide for selective power deposition inside a 0.15 mL bladder. A working prototype was constructed operating at 2.45 GHz. Heating performance was characterised by mapping fibre-optic temperature sensors along catheters inserted at depths of 0-1 mm (subcutaneous), 2-3 mm (vaginal), and 4-5 mm (rectal) below the abdominal wall, with the mid depth catheter adjacent to the bladder. Core temperature was monitored orally. Thermal measurements confirm the simulations which demonstrate that this applicator can provide local heating at depth in small animals. Measured temperatures in murine pelvis show well-localised bladder heating to 42-43°C while maintaining normothermic skin and core temperatures. Simulation techniques facilitate the design optimisation of microwave antennas for use in pre-clinical applications such as localised tumour heating in small animals. Laboratory measurements demonstrate the effectiveness of a new miniature water-coupled microwave applicator for localised heating of murine bladder.

Essential roles for Cdx in murine primitive hematopoiesis.

PubMed

Brooke-Bisschop, Travis; Savory, Joanne G A; Foley, Tanya; Ringuette, Randy; Lohnes, David

2017-02-15

The Cdx transcription factors play essential roles in primitive hematopoiesis in the zebrafish where they exert their effects, in part, through regulation of hox genes. Defects in hematopoiesis have also been reported in Cdx mutant murine embryonic stem cell models, however, to date no mouse model reflecting the zebrafish Cdx mutant hematopoietic phenotype has been described. This is likely due, in part, to functional redundancy among Cdx members and the early lethality of Cdx2 null mutants. To circumvent these limitations, we used Cre-mediated conditional deletion to assess the impact of concomitant loss of Cdx1 and Cdx2 on murine primitive hematopoiesis. We found that Cdx1/Cdx2 double mutants exhibited defects in primitive hematopoiesis and yolk sac vasculature concomitant with reduced expression of several genes encoding hematopoietic transcription factors including Scl/Tal1. Chromatin immunoprecipitation analysis revealed that Scl was occupied by Cdx2 in vivo, and Cdx mutant hematopoietic yolk sac differentiation defects could be rescued by expression of exogenous Scl. These findings demonstrate critical roles for Cdx members in murine primitive hematopoiesis upstream of Scl. Copyright © 2017 Elsevier Inc. All rights reserved.

School system evaluation by value added analysis under endogeneity.

PubMed

Manzi, Jorge; San Martín, Ernesto; Van Bellegem, Sébastien

2014-01-01

Value added is a common tool in educational research on effectiveness. It is often modeled as a (prediction of a) random effect in a specific hierarchical linear model. This paper shows that this modeling strategy is not valid when endogeneity is present. Endogeneity stems, for instance, from a correlation between the random effect in the hierarchical model and some of its covariates. This paper shows that this phenomenon is far from exceptional and can even be a generic problem when the covariates contain the prior score attainments, a typical situation in value added modeling. Starting from a general, model-free definition of value added, the paper derives an explicit expression of the value added in an endogeneous hierarchical linear Gaussian model. Inference on value added is proposed using an instrumental variable approach. The impact of endogeneity on the value added and the estimated value added is calculated accurately. This is also illustrated on a large data set of individual scores of about 200,000 students in Chile.

The murine Cd48 gene: allelic polymorphism in the IgV-like region.

PubMed

Cabrero, J G; Freeman, G J; Reiser, H

1998-12-01

The murine CD48 molecule is a member of the immunoglobulin superfamily which regulates the activation of T lymphocytes. prior cloning experiments using mRNA from two different mouse strains had yielded discrepant sequences within the IgV-like domain of murine CD48. To resolve this issue, we have directly sequenced genomic DNA of 10 laboratory strains and two inbred strains of wild origin. The results of our analysis reveal an allelic polymorphism within the IgV-like domain of murine CD48.

Endogenous Pyrogen Physiology

DTIC Science & Technology

1980-01-01

neutrophilic pyrogen, the fever-producing factors of cellular origin are now generally known as endogenous NEURONE $ M E pyrogen, or EP. FFECTS , ,, The entire...which release well known hormones. EP in turn produces its effect on a distant Assay of EP . target tissue, i.e., certein.. neurons within the central...expenditure, since it is not blocked by fluoride, cause CAMP formation within the neurons , or they could alter the In combination, these data suggest that

Social Laughter Triggers Endogenous Opioid Release in Humans.

PubMed

Manninen, Sandra; Tuominen, Lauri; Dunbar, Robin I; Karjalainen, Tomi; Hirvonen, Jussi; Arponen, Eveliina; Hari, Riitta; Jääskeläinen, Iiro P; Sams, Mikko; Nummenmaa, Lauri

2017-06-21

The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [ 11 C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold-a proxy of endogenous opioidergic activation-was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds. SIGNIFICANCE STATEMENT Social contacts are vital to humans. The size of human social networks significantly exceeds the network that can be maintained by social grooming in other primates. Here, we used PET to show that endogenous opioid release after social laughter may provide a neurochemical mechanism supporting long-term relationships in humans. Participants were scanned twice: after a 30 min social laughter session and after spending 30 min alone in the testing room (baseline). Endogenous opioid release was stronger after laughter versus the

PINK1 is required for timely cell-type specific mitochondrial clearance during Drosophila midgut metamorphosis.

PubMed

Liu, Yan; Lin, Jingjing; Zhang, Minjie; Chen, Kai; Yang, Shengxi; Wang, Qun; Yang, Hongqin; Xie, Shusen; Zhou, Yongjian; Zhang, Xi; Chen, Fei; Yang, Yufeng

2016-11-15

Mitophagy is the selective degradation of mitochondria by autophagy, which is an important mitochondrial quality and quantity control process. During Drosophila metamorphosis, the degradation of midgut involves a large change in length and organization, which is mediated by autophagy. Here we noticed a cell-type specific mitochondrial clearance process that occurs in enterocytes (ECs), while most mitochondria remain in intestinal stem cells (ISCs) during metamorphosis. Although PINK1/PARKIN represent the canonical pathway for the elimination of impaired mitochondria in varied pathological conditions, their roles in developmental processes or normal physiological conditions have been less studied. To examine the potential contribution of PINK1 in developmental processes, we monitored the dynamic expression pattern of PINK1 in the midgut development by taking advantage of a newly CRISPR/Cas9 generated knock-in fly strain expressing PINK1-mCherry fusion protein that presumably recapitulates the endogenous expression pattern of PINK1. We disclosed a spatiotemporal correlation between the expression pattern of PINK1 and the mitochondrial clearance or persistence in ECs or ISCs respectively. By mosaic genetic analysis, we then demonstrated that PINK1 and PARKIN function epistatically to mediate the specific timely removal of mitochondria, and are involved in global autophagy in ECs during Drosophila midgut metamorphosis, with kinase-dead PINK1 exerting dominant negative effects. Taken together, our studies concluded that the PINK1/PARKIN is crucial for timely cell-type specific mitophagy under physiological conditions and demonstrated again that Drosophila midgut metamorphosis might serve as an elegant in vivo model to study autophagy. Copyright © 2016 Elsevier Inc. All rights reserved.

The Neural Cell Adhesion Molecule-Derived (NCAM)-Peptide FG Loop (FGL) Mobilizes Endogenous Neural Stem Cells and Promotes Endogenous Regenerative Capacity after Stroke.

PubMed

Klein, Rebecca; Mahlberg, Nicolas; Ohren, Maurice; Ladwig, Anne; Neumaier, Bernd; Graf, Rudolf; Hoehn, Mathias; Albrechtsen, Morten; Rees, Stephen; Fink, Gereon Rudolf; Rueger, Maria Adele; Schroeter, Michael

2016-12-01

The neural cell adhesion molecule (NCAM)-derived peptide FG loop (FGL) modulates synaptogenesis, neurogenesis, and stem cell proliferation, enhances cognitive capacities, and conveys neuroprotection after stroke. Here we investigated the effect of subcutaneously injected FGL on cellular compartments affected by degeneration and regeneration after stroke due to middle cerebral artery occlusion (MCAO), namely endogenous neural stem cells (NSC), oligodendrocytes, and microglia. In addition to immunohistochemistry, we used non-invasive positron emission tomography (PET) imaging with the tracer [ 18 F]-fluoro-L-thymidine ([ 18 F]FLT) to visualize endogenous NSC in vivo. FGL significantly increased endogenous NSC mobilization in the neurogenic niches as evidenced by in vivo and ex vivo methods, and it induced remyelination. Moreover, FGL affected neuroinflammation. Extending previous in vitro results, our data show that the NCAM mimetic peptide FGL mobilizes endogenous NSC after focal ischemia and enhances regeneration by amplifying remyelination and modulating neuroinflammation via affecting microglia. Results suggest FGL as a promising candidate to promote recovery after stroke.

tirant, a newly discovered active endogenous retrovirus in Drosophila simulans.

PubMed

Akkouche, Abdou; Rebollo, Rita; Burlet, Nelly; Esnault, Caroline; Martinez, Sonia; Viginier, Barbara; Terzian, Christophe; Vieira, Cristina; Fablet, Marie

2012-04-01

Endogenous retroviruses have the ability to become permanently integrated into the genomes of their host, and they are generally transmitted vertically from parent to progeny. With the exception of gypsy, few endogenous retroviruses have been identified in insects. In this study, we describe the tirant endogenous retrovirus in a subset of Drosophila simulans natural populations. By focusing on the envelope gene, we show that the entire retroviral cycle (transcription, translation, and retrotransposition) can be completed for tirant within one population of this species.

Transduction of Schistosoma mansoni by vesicular stomatitis virus glycoprotein-pseudotyped Moloney murine leukemia retrovirus.

PubMed

Kines, Kristine J; Mann, Victoria H; Morales, Maria E; Shelby, Bryan D; Kalinna, Bernd H; Gobert, Geoffrey N; Chirgwin, Sharon R; Brindley, Paul J

2006-04-01

Retroviral transduction of cultured schistosomes offers a potential means to establish transgenic lines of schistosomes and thereby to facilitate the elucidation of schistosome gene function and expression. The Moloney murine leukemia retroviral (MMLV) vector pLNHX was modified to incorporate EGFP or luciferase reporter genes under control of schistosome endogenous gene promoters from the spliced leader RNA and HSP70 genes. These constructs and a plasmid encoding vesicular stomatitis virus glycoprotein (VSVG) were utilized along with GP2-293 cells to produce replication incompetent retrovirus particles pseudotyped with the VSVG envelope. Exposure of several developmental stages, including sporocysts, of Schistosoma mansoni to these virions was facilitated by incubation with polybrene and/or by centrifugation. The early stages of binding and uptake of virus to the parasite tegument were demonstrated by the immunofluorescence colocalization of VSVG envelope and retroviral capsid proteins. Southern hybridization analysis indicated the integration of proviral forms of the MMLV constructs in genomic DNA isolated from the virus exposed schistosomes. Furthermore, analysis of RNA isolated from virus treated parasites demonstrated the presence of transcripts encoding reporter transgenes. Together these results indicated productive transduction by VSVG pseudotyped MMLV of cultured schistosomes, and suggest a tractable route forward towards heritable schistosome transgenesis.

Endogenous opiates and behavior: 2007.

PubMed

Bodnar, Richard J

2008-12-01

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Amplification and chromosomal dispersion of human endogenous retroviral sequences

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

Steele, P.E.; Martin, M.A.; Rabson, A.B.

1986-09-01

Endogenous retroviral sequences have undergone amplification events involving both viral and flanking cellular sequences. The authors cloned members of an amplified family of full-length endogenous retroviral sequences. Genomic blotting, employing a flanking cellular DNA probe derived from a member of this family, revealed a similar array of reactive bands in both humans and chimpanzees, indicating that an amplification event involving retroviral and associated cellular DNA sequences occurred before the evolutionary separation of these two primates. Southern analyses of restricted somatic cell hybrid DNA preparations suggested that endogenous retroviral segments are widely dispersed in the human genome and that amplification andmore » dispersion events may be linked.« less

Detection of endogenous boldenone in the entire male horses.

PubMed

Ho, Emmie N M; Yiu, Kenneth C H; Tang, Francis P W; Dehennin, Louis; Plou, Philippe; Bonnaire, Yves; Wan, Terence S M

2004-09-05

Boldenone (1,2-dehydrotestosterone) is a common veterinary anabolic agent. Its structure is very similar to testosterone. Testosterone is endogenous in the horse, whereas there has been no report concerning the detection of endogenous boldenone. This paper reports the direct observation of sulphate conjugate of boldenone in equine urine from entires. The detection procedures involved solid-phase extraction, immunoaffinity column (IAC) purification, and then LC-MS-MS analysis on a Q-ToF instrument. The identification of boldenone sulphate has provided direct evidence for the endogenous nature of boldenone in entire male horses. Quantification data for the normal level of boldenone in Hong Kong racehorses will also be discussed.

On the Endogeneity of the Mean-Variance Efficient Frontier.

ERIC Educational Resources Information Center

Somerville, R. A.; O'Connell, Paul G. J.

2002-01-01

Explains that the endogeneity of the efficient frontier in the mean-variance model of portfolio selection is commonly obscured in portfolio selection literature and in widely used textbooks. Demonstrates endogeneity and discusses the impact of parameter changes on the mean-variance efficient frontier and on the beta coefficients of individual…

Murine models of H. pylori-induced gastritis and gastric adenocarcinoma.

PubMed

Krueger, Sabine; Roessner, Albert; Kuester, Doerthe

2011-10-15

Laboratory mice have become one of the best animal species for mechanistic studies in gastrointestinal research. Their abundant genetic information, the way of causing carcinogenesis easily by transgenic and gene knockout techniques, limited effort in time and costs, and their practicability provide advantages over other animal models. Meanwhile, several murine practical models have been established for the investigation of the initiation, expansion, and progression of gastritis and gastric carcinoma, for assessing the effects of bacterial, genetic and environmental factors, and for evaluating therapeutic and preventive strategies in gastric diseases. This article gives a review of murine models of gastritis and gastric cancer, placing emphasis on the models associated with Helicobacter pylori infection and techniques used in our laboratory. We discuss matters of murine gastric anatomy, as well as techniques of infection, tissue preparation, and histology. Copyright © 2011 Elsevier GmbH. All rights reserved.

Loss of VPS13C Function in Autosomal-Recessive Parkinsonism Causes Mitochondrial Dysfunction and Increases PINK1/Parkin-Dependent Mitophagy.

PubMed

Lesage, Suzanne; Drouet, Valérie; Majounie, Elisa; Deramecourt, Vincent; Jacoupy, Maxime; Nicolas, Aude; Cormier-Dequaire, Florence; Hassoun, Sidi Mohamed; Pujol, Claire; Ciura, Sorana; Erpapazoglou, Zoi; Usenko, Tatiana; Maurage, Claude-Alain; Sahbatou, Mourad; Liebau, Stefan; Ding, Jinhui; Bilgic, Basar; Emre, Murat; Erginel-Unaltuna, Nihan; Guven, Gamze; Tison, François; Tranchant, Christine; Vidailhet, Marie; Corvol, Jean-Christophe; Krack, Paul; Leutenegger, Anne-Louise; Nalls, Michael A; Hernandez, Dena G; Heutink, Peter; Gibbs, J Raphael; Hardy, John; Wood, Nicholas W; Gasser, Thomas; Durr, Alexandra; Deleuze, Jean-François; Tazir, Meriem; Destée, Alain; Lohmann, Ebba; Kabashi, Edor; Singleton, Andrew; Corti, Olga; Brice, Alexis

2016-03-03

Autosomal-recessive early-onset parkinsonism is clinically and genetically heterogeneous. The genetic causes of approximately 50% of autosomal-recessive early-onset forms of Parkinson disease (PD) remain to be elucidated. Homozygozity mapping and exome sequencing in 62 isolated individuals with early-onset parkinsonism and confirmed consanguinity followed by data mining in the exomes of 1,348 PD-affected individuals identified, in three isolated subjects, homozygous or compound heterozygous truncating mutations in vacuolar protein sorting 13C (VPS13C). VPS13C mutations are associated with a distinct form of early-onset parkinsonism characterized by rapid and severe disease progression and early cognitive decline; the pathological features were striking and reminiscent of diffuse Lewy body disease. In cell models, VPS13C partly localized to the outer membrane of mitochondria. Silencing of VPS13C was associated with lower mitochondrial membrane potential, mitochondrial fragmentation, increased respiration rates, exacerbated PINK1/Parkin-dependent mitophagy, and transcriptional upregulation of PARK2 in response to mitochondrial damage. This work suggests that loss of function of VPS13C is a cause of autosomal-recessive early-onset parkinsonism with a distinctive phenotype of rapid and severe progression. Copyright © 2016 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Behavior of a cloned murine interferon alpha/beta receptor expressed in homospecific or heterospecific background.

PubMed Central

Uzé, G; Lutfalla, G; Bandu, M T; Proudhon, D; Mogensen, K E

1992-01-01

A murine interferon (IFN) alpha/beta receptor was cloned from the IFN-sensitive L1210 cell line on the basis of its homology with the human receptor. A combination of methods that includes the screening of random-primed and oligo(dT)-primed cDNA libraries and polymerase chain reactions with a single-side specificity was used. At the amino acid level, the murine IFN-alpha/beta shows 46% identity with its human counterpart. Both human WISH cells presenting a low sensitivity to mouse IFN and a murine L1210 mutant subline that does not express the receptor have been stably transfected with the murine IFN-alpha/beta receptor. Whereas transfected human cells became sensitive to a limited number of mouse IFN-alpha/beta subtypes, the transfected murine L1210 mutant was found to be fully complemented and became sensitive to all mouse IFN-alpha/beta subtypes tested, including those that were not active on transfected human cells. These results strongly suggest that the receptor described here is implicated in the mediation of the activities of all murine IFN-alpha/beta subtypes. Images PMID:1533935

Do Endogenous and Exogenous Action Control Compete for Perception?

ERIC Educational Resources Information Center

Pfister, Roland; Heinemann, Alexander; Kiesel, Andrea; Thomaschke, Roland; Janczyk, Markus

2012-01-01

Human actions are guided either by endogenous action plans or by external stimuli in the environment. These two types of action control seem to be mediated by neurophysiologically and functionally distinct systems that interfere if an endogenously planned action suddenly has to be performed in response to an exogenous stimulus. In this case, the…

Growth and metabolism of murine and bovine embryos in bovine uterine flushing-supplemented culture media.

PubMed Central

Rondeau, M; Guay, P; Goff, A K; Cooke, G M

1996-01-01

The aim of this study was to compare the development and metabolic activity of cultured murine and bovine embryos in 2 standard media (HAM F-10 and RPMI) in the presence or absence of bovine uterine flushings. Murine morulae (n = 653) and day 7 bovine embryos (n = 273) were cultured for 18 h or 36 h in either HAM F-10 or RPMI in the presence or absence of bovine uterine flushings. After culture, the development, quality, and metabolic activity (glucose utilization or methionine uptake and incorporation) of embryos was assessed. It was found that HAM F-10 (without uterine flushings) was a more suitable medium than RPMI for optimal development and metabolism of murine and bovine embryos. Poor quality and development, as well as decreased metabolism, were evident after culture of murine embryos in RPMI; in contrast, this medium had no adverse effects on bovine embryos in culture. Supplementation of HAM F-10 with bovine uterine flushings improved the growth of murine embryos and the protein synthesis (as measured by an increased methionine incorporation) for both murine and bovine embryos. However, supplementation with bovine uterine flushings could not overcome deficiencies of an inappropriate medium (RPMI) for murine embryos. Supplementation of a well-defined culture medium with uterine flushings increased metabolism of embryos in culture, and thus might help to increase pregnancy rates after transfer of such embryos to recipient cows. PMID:8825988

Do endogenous and exogenous action control compete for perception?

PubMed

Pfister, Roland; Heinemann, Alexander; Kiesel, Andrea; Thomaschke, Roland; Janczyk, Markus

2012-04-01

Human actions are guided either by endogenous action plans or by external stimuli in the environment. These two types of action control seem to be mediated by neurophysiologically and functionally distinct systems that interfere if an endogenously planned action suddenly has to be performed in response to an exogenous stimulus. In this case, the endogenous representation has to be deactivated first to give way to the exogenous system. Here we show that interference of endogenous and exogenous action control is not limited to motor-related aspects but also affects the perception of action-related stimuli. Participants associated two actions with contingent sensory effects in learning blocks. In subsequent test blocks, preparing one of these actions specifically impaired responding to the associated effect in an exogenous speeded detection task, yielding a blindness-like effect for arbitrary, learned action effects. In accordance with the theory of event coding, this finding suggests that action planning influences perception even in the absence of any physical similarities between action and to-be-perceived stimuli.

Human beta-globin mRNAs that harbor a nonsense codon are degraded in murine erythroid tissues to intermediates lacking regions of exon I or exons I and II that have a cap-like structure at the 5' termini.

PubMed Central

Lim, S K; Maquat, L E

1992-01-01

Previous studies have demonstrated that nonsense codons within beta zero-thalassemic or in vitro-mutagenized human beta-globin transgenes result in the production of mRNAs that are degraded abnormally rapidly in the cytoplasm of murine erythroid cells. As a consequence, three RNA degradative intermediates are formed that lack sequences from either exon I or exons I and II. We show here that the intermediates, like the full-length mRNA from which they derive and the endogenous murine beta maj-globin mRNA, bind to the anticap monoclonal antibody H-20 in a way that is competed by the cap analogue m7G and eliminated by prior exposure to tobacco acid pyrophosphatase. Furthermore, the intermediates, like the two full-length mRNAs, are resistant to a 5'----3' exonuclease activity isolated from HeLa cell nuclei that degrades uncapped but not capped ribopolymers. Based on these observations, the intermediates appear to possess a structure that is indistinguishable from the cap at the 5' end of mRNA, i.e. a methylated nucleoside that is linked to the RNA by a 5'-5' phosphodiester bond. Detection of the intermediates during murine development was concomitant with detection of full-length thalassemic mRNA. Intermediate production appears to be influenced by RNA structure as indicated by the products that derive from a beta zero-thalassemic beta-globin transgene harboring a structural alteration (a 4 bp deletion) that was larger than any of those previously studied. Images PMID:1324170

Endogenous Opiates and Behavior: 2015.

PubMed

Bodnar, Richard J

2017-02-01

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Endogenous opiates and behavior: 2013.

PubMed

Bodnar, Richard J

2014-12-01

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses. Copyright © 2014 Elsevier Inc. All rights reserved.

Endogenous opiates and behavior: 2004.

PubMed

Bodnar, Richard J; Klein, Gad E

2005-12-01

This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Diagnostic imaging advances in murine models of colitis.

PubMed

Brückner, Markus; Lenz, Philipp; Mücke, Marcus M; Gohar, Faekah; Willeke, Peter; Domagk, Dirk; Bettenworth, Dominik

2016-01-21

Inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are chronic-remittent inflammatory disorders of the gastrointestinal tract still evoking challenging clinical diagnostic and therapeutic situations. Murine models of experimental colitis are a vital component of research into human IBD concerning questions of its complex pathogenesis or the evaluation of potential new drugs. To monitor the course of colitis, to the present day, classical parameters like histological tissue alterations or analysis of mucosal cytokine/chemokine expression often require euthanasia of animals. Recent advances mean revolutionary non-invasive imaging techniques for in vivo murine colitis diagnostics are increasingly available. These novel and emerging imaging techniques not only allow direct visualization of intestinal inflammation, but also enable molecular imaging and targeting of specific alterations of the inflamed murine mucosa. For the first time, in vivo imaging techniques allow for longitudinal examinations and evaluation of intra-individual therapeutic response. This review discusses the latest developments in the different fields of ultrasound, molecularly targeted contrast agent ultrasound, fluorescence endoscopy, confocal laser endomicroscopy as well as tomographic imaging with magnetic resonance imaging, computed tomography and fluorescence-mediated tomography, discussing their individual limitations and potential future diagnostic applications in the management of human patients with IBD.

Regulation of murine cystic fibrosis transmembrane conductance regulator Cl− channels expressed in Chinese hamster ovary cells

PubMed Central

Lansdell, K A; Kidd, J F; Delaney, S J; Wainwright, B J; Sheppard, D N

1998-01-01

We investigated the effect of protein kinases and phosphatases on murine cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels, expressed in Chinese hamster ovary (CHO) cells, using iodide efflux and the excised inside-out configuration of the patch-clamp technique.The protein kinase C (PKC) activator, phorbol dibutyrate, enhanced cAMP-stimulated iodide efflux. However, PKC did not augment the single-channel activity of either human or murine CFTR Cl− channels that had previously been activated by protein kinase A.Fluoride, a non-specific inhibitor of protein phosphatases, stimulated both human and murine CFTR Cl− channels. However, calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, did not enhance cAMP-stimulated iodide efflux.The alkaline phosphatase inhibitor, (−)-bromotetramisole augmented cAMP-stimulated iodide efflux and, by itself, stimulated a larger efflux than that evoked by cAMP agonists. However, (+)-bromotetramisole, the inactive enantiomer, had the same effect. For murine CFTR, neither enantiomer enhanced single-channel activity. In contrast, both enantiomers increased the open probability (Po) of human CFTR, suggesting that bromotetramisole may promote the opening of human CFTR.As murine CFTR had a low Po and was refractory to stimulation by activators of human CFTR, we investigated whether murine CFTR may open to a subconductance state. When single-channel records were filtered at 50 Hz, a very small subconductance state of murine CFTR was observed that had a Po greater than that of human CFTR. The occupancy of this subconductance state may explain the differences in channel regulation observed between human and murine CFTR. PMID:9769419

IDH1(R132H) mutation increases murine haematopoietic progenitors and alters epigenetics.

PubMed

Sasaki, Masato; Knobbe, Christiane B; Munger, Joshua C; Lind, Evan F; Brenner, Dirk; Brüstle, Anne; Harris, Isaac S; Holmes, Roxanne; Wakeham, Andrew; Haight, Jillian; You-Ten, Annick; Li, Wanda Y; Schalm, Stefanie; Su, Shinsan M; Virtanen, Carl; Reifenberger, Guido; Ohashi, Pamela S; Barber, Dwayne L; Figueroa, Maria E; Melnick, Ari; Zúñiga-Pflücker, Juan-Carlos; Mak, Tak W

2012-08-30

Mutations in the IDH1 and IDH2 genes encoding isocitrate dehydrogenases are frequently found in human glioblastomas and cytogenetically normal acute myeloid leukaemias (AML). These alterations are gain-of-function mutations in that they drive the synthesis of the ‘oncometabolite’ R-2-hydroxyglutarate (2HG). It remains unclear how IDH1 and IDH2 mutations modify myeloid cell development and promote leukaemogenesis. Here we report the characterization of conditional knock-in (KI) mice in which the most common IDH1 mutation, IDH1(R132H), is inserted into the endogenous murine Idh1 locus and is expressed in all haematopoietic cells (Vav-KI mice) or specifically in cells of the myeloid lineage (LysM-KI mice). These mutants show increased numbers of early haematopoietic progenitors and develop splenomegaly and anaemia with extramedullary haematopoiesis, suggesting a dysfunctional bone marrow niche. Furthermore, LysM-KI cells have hypermethylated histones and changes to DNA methylation similar to those observed in human IDH1- or IDH2-mutant AML. To our knowledge, our study is the first to describe the generation and characterization of conditional IDH1(R132H)-KI mice, and also the first report to demonstrate the induction of a leukaemic DNA methylation signature in a mouse model. Our report thus sheds light on the mechanistic links between IDH1 mutation and human AML.

Endogenous analgesic effect of pregabalin: A double-blind and randomized controlled trial.

PubMed

Sugimine, S; Saito, S; Araki, T; Yamamoto, K; Obata, H

2017-07-01

Conditioned pain modulation (CPM) is widely used to measure endogenous analgesia, and a recent study indicated that drugs that act on endogenous analgesia are more effective in individuals with lower CPM. Recent animal studies have indicated that pregabalin activates endogenous analgesia by stimulating the descending pain inhibitory system. The present study examined whether the analgesic effect of pregabalin is greater in individuals with lower original endogenous analgesia using CPM. Fifty-nine healthy subjects were randomly assigned to either a pregabalin group or a placebo group, and 50 of them completed the study. CPM was measured before and after pregabalin or placebo administration. The correlation of initial CPM to change in CPM was compared between the pregabalin and placebo groups. Initial CPM was significantly correlated with the change in CPM in the pregabalin group (r = -0.73, p < 0.0001) but not in the placebo group (p = 0.56) (difference in correlation coefficients between groups; p = 0.004). Furthermore, the initial CPM significantly affected the change in CPM in the pregabalin group but not in the placebo group (pregabalin group: adj R 2  = 0.51, p < 0.001, y = -0.54x + 2.98; placebo group: p = 0.56, significant difference in regression slopes; p = 0.015). These results indicate that pregabalin has a higher endogenous analgesic effect in individuals with lower original endogenous analgesia. The analgesic effect of pregabalin depends on the original endogenous analgesia status. Its effect on conditioned pain modulation (CPM) was stronger for subjects with lower original endogenous analgesia, suggesting that the mechanism of pregabalin involves the improvement of endogenous analgesia. © 2017 European Pain Federation - EFIC®.

Endogenous network of firms and systemic risk

NASA Astrophysics Data System (ADS)

Ma, Qianting; He, Jianmin; Li, Shouwei

2018-02-01

We construct an endogenous network characterized by commercial credit relationships connecting the upstream and downstream firms. Simulation results indicate that the endogenous network model displays a scale-free property which exists in real-world firm systems. In terms of the network structure, with the expansion of the scale of network nodes, the systemic risk increases significantly, while the heterogeneities of network nodes have no effect on systemic risk. As for firm micro-behaviors, including the selection range of trading partners, actual output, labor requirement, price of intermediate products and employee salaries, increase of all these parameters will lead to higher systemic risk.

[Mechanisms of leukocyte formation of endogenous pyrogen].

PubMed

Rybakina, E G; Sorokin, A V

1982-06-01

A study was made of the kinetics of endogenous pyrogen production by rabbit blood and exudate leukocytes and possible role played by the products of activated leukocytes in autoregulation of the process. It was established that accumulation of endogenous pyrogen in the cell precedes its release by stimulated cells. Then the processes of active pyrogen formation and release gel interdependent: pyrogen formed releases from the cell; the lowering of pyrogen concentration in the cell is accompanied by the decrease of its content in the medium. No stimulating effect of the products activated during leukocyte inflammation on pyrogen formation by blood leukocytes was discovered.

Endogenous opioids encode relative taste preference.

PubMed

Taha, Sharif A; Norsted, Ebba; Lee, Lillian S; Lang, Penelope D; Lee, Brian S; Woolley, Joshua D; Fields, Howard L

2006-08-01

Endogenous opioid signaling contributes to the neural control of food intake. Opioid signaling is thought to regulate palatability, the reward value of a food item as determined by orosensory cues such as taste and texture. The reward value of a food reflects not only these sensory properties but also the relative value of competing food choices. In the present experiment, we used a consummatory contrast paradigm to manipulate the relative value of a sucrose solution for two groups of rats. Systemic injection of the nonspecific opioid antagonist naltrexone suppressed sucrose intake; for both groups, however, this suppression was selective, occurring only for the relatively more valuable sucrose solution. Our results indicate that endogenous opioid signaling contributes to the encoding of relative reward value.

Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy.

PubMed

Di Sante, Gabriele; Casimiro, Mathew C; Pestell, Timothy G; Pestell, Richard G

2016-05-04

Time-lapse video microscopy can be defined as the real time imaging of living cells. This technique relies on the collection of images at different time points. Time intervals can be set through a computer interface that controls the microscope-integrated camera. This kind of microscopy requires both the ability to acquire very rapid events and the signal generated by the observed cellular structure during these events. After the images have been collected, a movie of the entire experiment is assembled to show the dynamic of the molecular events of interest. Time-lapse video microscopy has a broad range of applications in the biomedical research field and is a powerful and unique tool for following the dynamics of the cellular events in real time. Through this technique, we can assess cellular events such as migration, division, signal transduction, growth, and death. Moreover, using fluorescent molecular probes we are able to mark specific molecules, such as DNA, RNA or proteins and follow them through their molecular pathways and functions. Time-lapse video microscopy has multiple advantages, the major one being the ability to collect data at the single-cell level, that make it a unique technology for investigation in the field of cell biology. However, time-lapse video microscopy has limitations that can interfere with the acquisition of high quality images. Images can be compromised by both external factors; temperature fluctuations, vibrations, humidity and internal factors; pH, cell motility. Herein, we describe a protocol for the dynamic acquisition of a specific protein, Parkin, fused with the enhanced yellow fluorescent protein (EYFP) in order to track the selective removal of damaged mitochondria, using a time-lapse video microscopy approach.

Endogenous Serratia marcescens endophthalmitis.

PubMed

Shah, Sonya B; Bansal, Alok S; Rabinowitz, Michael P; Park, Carl; Bedrossian, Edward H; Eagle, Ralph C

2014-01-01

The purpose of this study was to describe a rare case of endogenous endophthalmitis associated with dental disease secondary to Serratia marcescens in an HIV-negative individual. Retrospective case report. A 50-year-old white man with a history of intravenous drug use presented with pain and decreased vision in his right eye. Slit-lamp examination showed a hazy cornea, hypopyon with fibrin in the anterior chamber, and elevated intraocular pressure. B-scan ultrasound showed vitritis and choroidal thickening. Computed tomography showed gingival inflammation and lucencies of several teeth. Blood and urine cultures were negative, and HIV testing was negative. Echocardiography was negative for vegetations. Intravitreal culture revealed S. marcescens. Despite intravitreal and systemic antibiotics, the patient's clinical situation rapidly deteriorated, and the eye was eviscerated. The patient underwent dental extraction and was subsequently discharged in stable condition. The first case of endogenous endophthalmitis secondary to S. marcescens in an otherwise healthy, HIV-negative, intravenous drug user in association with severe dental disease is reported. Serratia may be found in oral biofilm, and this mechanism should be considered in cases where other etiologies have been ruled out.

Residential water demand with endogenous pricing: The Canadian Case

NASA Astrophysics Data System (ADS)

Reynaud, Arnaud; Renzetti, Steven; Villeneuve, Michel

2005-11-01

In this paper, we show that the rate structure endogeneity may result in a misspecification of the residential water demand function. We propose to solve this endogeneity problem by estimating a probabilistic model describing how water rates are chosen by local communities. This model is estimated on a sample of Canadian local communities. We first show that the pricing structure choice reflects efficiency considerations, equity concerns, and, in some cases, a strategy of price discrimination across consumers by Canadian communities. Hence estimating the residential water demand without taking into account the pricing structures' endogeneity leads to a biased estimation of price and income elasticities. We also demonstrate that the pricing structure per se plays a significant role in influencing price responsiveness of Canadian residential consumers.

An endogenous small interfering RNA pathway in Drosophila

PubMed Central

Czech, Benjamin; Malone, Colin D.; Zhou, Rui; Stark, Alexander; Schlingeheyde, Catherine; Dus, Monica; Perrimon, Norbert; Kellis, Manolis; Wohlschlegel, James A.; Sachidanandam, Ravi; Hannon, Gregory J.; Brennecke, Julius

2009-01-01

Drosophila endogenous small RNAs are categorized according to their mechanisms of biogenesis and the Argonaute protein to which they bind. MicroRNAs are a class of ubiquitously expressed RNAs of ~22 nucleotides in length, which arise from structured precursors through the action of Drosha–Pasha and Dicer-1–Loquacious complexes1–7. These join Argonaute-1 to regulate gene expression8,9. A second endogenous small RNA class, the Piwi-interacting RNAs, bind Piwi proteins and suppress transposons10,11. Piwi-interacting RNAs are restricted to the gonad, and at least a subset of these arises by Piwi-catalysed cleavage of single-stranded RNAs12,13. Here we show that Drosophila generates a third small RNA class, endogenous small interfering RNAs, in both gonadal and somatic tissues. Production of these RNAs requires Dicer-2, but a subset depends preferentially on Loquacious1,4,5 rather than the canonical Dicer-2 partner, R2D2 (ref. 14). Endogenous small interfering RNAs arise both from convergent transcription units and from structured genomic loci in a tissue-specific fashion. They predominantly join Argonaute-2 and have the capacity, as a class, to target both protein-coding genes and mobile elements. These observations expand the repertoire of small RNAs in Drosophila, adding a class that blurs distinctions based on known biogenesis mechanisms and functional roles. PMID:18463631

Significance of major international seaports in the distribution of murine typhus in Taiwan.

PubMed

Kuo, Chi-Chien; Wardrop, Nicola; Chang, Chung-Te; Wang, Hsi-Chieh; Atkinson, Peter M

2017-03-01

International seaports are hotspots for disease invasion and pathogens can persist in seaports even after ports are abandoned. Transmitted by fleas infected by Rickettsia typhi, murine typhus, a largely neglected and easily misdiagnosed disease, is known to occur primarily in large seaports. However, the significance of seaports in the occurrence of murine typhus has never been validated quantitatively. We studied the spatial distribution of murine typhus, a notifiable disease, in Taiwan. We investigated whether risk of infection was correlated with distance to international seaports and a collection of environmental and socioeconomic factors, using a Bayesian negative binomial conditionally autoregressive model, followed with geographically weighted regression. Seaports that are currently in use and those that operated in the 19th century for trade with China, but were later abandoned due to siltation were analyzed. A total of 476 human cases of murine typhus were reported during 2000-2014 in the main island of Taiwan, with spatial clustering in districts in southwest and central-west Taiwan. A higher incidence rate (case/population) was associated with a smaller distance to currently in-use international seaports and lower rainfall and temperature, but was uncorrelated with distance to abandoned ports. Geographically weighted regression revealed a geographic heterogeneity in the importance of distance to in-use seaports near the four international seaports of Taiwan. Our study suggests that murine typhus is associated with international seaports, especially for those with large trading volume. Thus, one of the costs of global trade in Taiwan might be elevated risks of murine typhus. Globalization has accelerated the spread of infectious diseases, but the burden of disease varies geographically, with regions surrounding major international seaports warranting particular surveillance.

Murine typhus in two travelers returning from Bali, Indonesia: an underdiagnosed disease.

PubMed

Takeshita, Nozomi; Imoto, Kazuya; Ando, Shuji; Yanagisawa, Kunio; Ohji, Goh; Kato, Yasuyuki; Sakata, Akiko; Hosokawa, Naoto; Kishimoto, Toshio

2010-01-01

Two Japanese travelers from Bali were diagnosed with murine typhus in Japan during the same period. Although one had only mild illness, the other experienced liver and kidney dysfunction. Murine typhus may be missed not only in endemic areas around the world, but also in travelers, especially those returning from marine resorts in these areas. © 2010 International Society of Travel Medicine.

The search for an endogenous activator.

PubMed Central

Gekowski, K. M.; Atkins, E.

1985-01-01

Certain febrile diseases are unaccompanied by infection or apparent hypersensitivity. In myocardial infarction or pulmonary embolism, for example, fever has been attributed to inflammation and/or tissue necrosis. Exogenous (microbial) pyrogens stimulate both human and animal monocytes/macrophages to produce endogenous pyrogen (EP) in vitro. To determine if plasma and cellular endogeneous mediators (EMs) of inflammation induced EP production, human mononuclear cells (M/L) were incubated for 18 hours with varying amounts of EM and the supernates assayed for EP in rabbits. Neutrophils (PMNs), which do not generate EP and yet are a feature of acute inflammation, were tested. Neither viable, phorbol myristic acetate-stimulated PMNs nor sonicated PMNs, red blood cells, or M/L stimulated human monocytes to produce EP. Human C3b and C5a, which mediate phagocytosis and chemotaxis, respectively, were also inactive. Despite its chemoattractant properties, the synthetic peptide FMLP failed to induce EP release. Since Poly I:Poly C (PIC: a synthetic, double-stranded RNA) is a potent pyrogen in rabbits, we investigated PIC, as well as a native, single-stranded RNA (from E. coli) and DNA (from calf thymus). None was active in vitro, and only PIC caused fever when given to rabbits intravenously. In summary, we have been unable to find an endogenous activator of EP from human monocytes to explain fevers associated with inflammation alone. PMID:3875936

Recombinant probes for visualizing endogenous synaptic proteins in living neurons

PubMed Central

Gross, Garrett G.; Junge, Jason A.; Mora, Rudy J.; Kwon, Hyung-Bae; Olson, C. Anders; Takahashi, Terry T.; Liman, Emily R.; Ellis-Davies, Graham C.R.; McGee, Aaron W.; Sabatini, Bernardo L.; Roberts, Richard W.; Arnold, Don B.

2013-01-01

Summary The ability to visualize endogenous proteins in living neurons provides a powerful means to interrogate neuronal structure and function. Here we generate recombinant antibody-like proteins, termed FingRs (Fibronectin intrabodies generated with mRNA display), that bind endogenous neuronal proteins PSD-95 and Gephyrin with high affinity and which, when fused to GFP, allow excitatory and inhibitory synapses to be visualized in living neurons. Design of the FingR incorporates a novel transcriptional regulation system that ties FingR expression to the level of the target and reduces background fluorescence. In dissociated neurons and brain slices FingRs generated against PSD-95 and Gephyrin did not affect the expression patterns of their endogenous target proteins or the number or strength of synapses. Together, our data indicate that PSD-95 and Gephyrin FingRs can report the localization and amount of endogenous synaptic proteins in living neurons and thus may be used to study changes in synaptic strength in vivo. PMID:23791193

Identification of endogenous flurophores in the layered retina

NASA Astrophysics Data System (ADS)

Xu, Gaixia; Chen, Danni; Sun, Yiwen; Qu, Junle; Lin, Ziyang; Ding, Zhihua; Niu, Hanben

2007-05-01

In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment epithelium cells exhibited strong autofluorescence with as emission peak of 600+/-10nm when excited with 860-nm light. The emission peak of photoreceptors was at 652+/-5nm, and the emission peak of retinal vessels layer was weak and at 640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which suggested that there wasn't only one endogenous fluorophores of tissues excited.

Endogenous small RNAs and antibacterial immunity in plants.

PubMed

Jin, Hailing

2008-08-06

Small RNAs are non-coding regulatory RNA molecules that control gene expression by mediating mRNA degradation, translational inhibition, or chromatin modification. Virus-derived small RNAs induce silencing of viral RNAs and are essential for antiviral defense in both animal and plant systems. The role of host endogenous small RNAs on antibacterial immunity has only recently been recognized. Host disease resistance and defense responses are achieved by activation and repression of a large array of genes. Certain endogenous small RNAs in plants, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are induced or repressed in response to pathogen attack and subsequently regulate the expression of genes involved in disease resistance and defense responses by mediating transcriptional or post-transcriptional gene silencing. Thus, these small RNAs play an important role in gene expression reprogramming in plant disease resistance and defense responses. This review focuses on the recent findings of plant endogenous small RNAs in antibacterial immunity.

Endophilins interact with Moloney murine leukemia virus Gag and modulate virion production

PubMed Central

Wang, Margaret Q; Kim, Wankee; Gao, Guangxia; Torrey, Ted A; Morse, Herbert C; De Camilli, Pietro; Goff, Stephen P

2004-01-01

Background The retroviral Gag protein is the central player in the process of virion assembly at the plasma membrane, and is sufficient to induce the formation and release of virus-like particles. Recent evidence suggests that Gag may co-opt the host cell's endocytic machinery to facilitate retroviral assembly and release. Results A search for novel partners interacting with the Gag protein of the Moloney murine leukemia virus (Mo-MuLV) via the yeast two-hybrid protein-protein interaction assay resulted in the identification of endophilin 2, a component of the machinery involved in clathrin-mediated endocytosis. We demonstrate that endophilin interacts with the matrix or MA domain of the Gag protein of Mo-MuLV, but not of human immunodeficiency virus, HIV. Both exogenously expressed and endogenous endophilin are incorporated into Mo-MuLV viral particles. Titration experiments suggest that the binding sites for inclusion of endophilin into viral particles are limited and saturable. Knock-down of endophilin with small interfering RNA (siRNA) had no effect on virion production, but overexpression of endophilin and, to a lesser extent, of several fragments of the protein, result in inhibition of Mo-MuLV virion production, but not of HIV virion production. Conclusions This study shows that endophilins interact with Mo-MuLV Gag and affect virion production. The findings imply that endophilin is another component of the large complex that is hijacked by retroviruses to promote virion production. PMID:14659004

Clinical and laboratory features of murine typhus in central Tunisia: a report of seven cases.

PubMed

Letaïef, A Omezzine; Kaabia, N; Chakroun, M; Khalifa, M; Bouzouaia, N; Jemni, L

2005-11-01

Murine or endemic typhus, caused by Rickettsia typhi, has been reported in all continents. In the 1970s, no cases of murine typhus were diagnosed in Tunisia. The clinico-epidemiological characteristics of seven cases of murine typhus diagnosed at our hospitals since 1993 are reported. Diagnosis was confirmed by indirect fluorescence assay detecting specific R. typhi antibodies. Murine typhus occurred in all ages from 18-80 years during the hot season in rural areas. Clinical features were: sudden onset of fever and absence of eschar in all cases, with maculo-papular rash (five cases), prostration (four cases), meningism (three cases) and pneumonia (four cases). Frequent laboratory findings were moderate thrombopenia (four cases) and elevated transaminases (four cases). Before the results of serology, clinical diagnoses were Mediterranean Spotted Fever (four cases), Q fever (one case), pneumonia (one case), and lymphocytic meningitis (one case). Serology confirmed all diagnoses with cross-reactivity with Rickettsia conorii. Murine typhus exists in Tunisia and its prevalence is underestimated. Further, more specific studies are needed to evaluate the true prevalence.

Effects of theobroxide, a natural product, on the level of endogenous jasmonoids.

PubMed

Yang, Qing; Gao, Xiquan; Fujino, Yumiko; Matsuura, Hideyuki; Yoshihara, Teruhiko

2004-01-01

The natural potato microtuber inducing substance, theobroxide, strongly induces the formation of tuber of potato (Solanum tuberosum L.) and flower bud of morning glory (Pharbitis nil) plants under non-inducing conditions (long days) (Yoshihara et al., 2000). In the present study, theobroxide was evaluated for its effect on the level of endogenous jasmonoids in different tissues of such two plants. An in vitro bioassay using cultures of single-node segments of potato stems was performed with the supplement of theobroxide in the medium. The endogenous jasmonic acid (JA) and its analogue tuberonic acid (TA, 12-hydroxyjasmonic acid) in segments and microtubers were quantitatively analyzed. The increase in the endogenous JA level caused by theobroxide was observed in both segments and microtubers. Endogenous TA was only detected in segments, and the content increased with the concentration of theobroxide. As for morning glory, the whole plant was sprayed with theobroxide for 1 approximately 5 weeks under different photoperiods and endogenous JA in the leaves was quantitatively analyzed. Theobroxide spraying increased the level of endogenous JA in the leaves of the plants grown under both long and short days.

Animal spirits, competitive markets, and endogenous growth

NASA Astrophysics Data System (ADS)

Miyazaki, Kenji

2013-10-01

This paper uses a simple model with an endogenous discount rate and linear technology to investigate whether a competitive equilibrium has a higher balanced growth path (BGP) than the social planning solution and whether the BGP is determinate or indeterminate. The implications are as follows. To start with, people with an instinct to compare themselves with others possess an endogenous discount rate. In turn, this instinct affects the economic growth rate in a competitive market economy. The competitive market economy also sometimes achieves higher economic growth than a social planning economy. However, the outcomes of market economy occasionally fluctuate because of the presence of the self-fulfilling prophecy or animal spirits.

The Murine Factor H-Related Protein FHR-B Promotes Complement Activation.

PubMed

Cserhalmi, Marcell; Csincsi, Ádám I; Mezei, Zoltán; Kopp, Anne; Hebecker, Mario; Uzonyi, Barbara; Józsi, Mihály

2017-01-01

Factor H-related (FHR) proteins consist of varying number of complement control protein domains that display various degrees of sequence identity to respective domains of the alternative pathway complement inhibitor factor H (FH). While such FHR proteins are described in several species, only human FHRs were functionally investigated. Their biological role is still poorly understood and in part controversial. Recent studies on some of the human FHRs strongly suggest a role for FHRs in enhancing complement activation via competing with FH for binding to certain ligands and surfaces. The aim of the current study was the functional characterization of a murine FHR, FHR-B. To this end, FHR-B was expressed in recombinant form. Recombinant FHR-B bound to human C3b and was able to compete with human FH for C3b binding. FHR-B supported the assembly of functionally active C3bBb alternative pathway C3 convertase via its interaction with C3b. This activity was confirmed by demonstrating C3 activation in murine serum. In addition, FHR-B bound to murine pentraxin 3 (PTX3), and this interaction resulted in murine C3 fragment deposition due to enhanced complement activation in mouse serum. FHR-B also induced C3 deposition on C-reactive protein, the extracellular matrix (ECM) extract Matrigel, and endothelial cell-derived ECM when exposed to mouse serum. Moreover, mouse C3 deposition was strongly enhanced on necrotic Jurkat T cells and the mouse B cell line A20 by FHR-B. FHR-B also induced lysis of sheep erythrocytes when incubated in mouse serum with FHR-B added in excess. Altogether, these data demonstrate that, similar to human FHR-1 and FHR-5, mouse FHR-B modulates complement activity by promoting complement activation via interaction with C3b and via competition with murine FH.

Cryoprotective effects of low-density lipoproteins, trehalose and soybean lecithin on murine spermatogonial stem cells.

PubMed

Wang, Peng; Li, Ying; Hu, Xiao-Chen; Cai, Xiao-Li; Hou, Li-Peng; Wang, Yan-Feng; Hu, Jian-Hong; Li, Qing-Wang; Suo, Li-Juan; Fan, Zhi-Guo; Zhang, Bo

2014-05-01

Spermatogonial stem cells (SSCs) have the ability to self-renew and offer a pathway for genetic engineering of the male germ line. Cryopreservation of SSCs has potential value for the treatment of male infertility, spermatogonial transplantation, and so on. In order to investigate the cryopreservation effects of different cryoprotectants on murine SSCs, 0.2 M of low-density lipoproteins (LDL), trehalose and soybean lecithin were added to the cryoprotective medium, respectively, and the murine SSCs were frozen at -80°C or -196°C. The results indicated that the optimal recovery rates of murine SSCs in the cryoprotective medium supplemented with LDL, trehalose and soybean lecithin were 92.53, 76.35 and 75.48% at -80°C, respectively. Compared with freezing at -196°C, the optimum temperature for improvement of recovery rates of frozen murine SSCs, cryopreservation in three different cryoprotectants at -80°C, were 17.11, 6.68 and 10.44% respectively. The recovery rates of murine SSCs in the cryoprotective medium supplemented with 0.2 M LDL were significantly higher than that of other cryoprotectants (P < 0.05). Moreover, the recovery rates were demonstrated to be greater at -80°C compared with at -196°C (P < 0.05). In conclusion, 0.2 M of LDL could significantly protect murine SSCs at -80°C. In the freezing-thawing process, LDL is responsible for the cryopreservation of murine SSCs because it can form a protective film at the surface of membranes. However, more research is needed to evaluate and understand the precise role of LDL during the freezing-thawing of SSCs.

Endogenous lentivirus in Malayan colugo (Galeopterus variegatus), a close relative of primates.

PubMed

Hron, Tomáš; Fábryová, Helena; Pačes, Jan; Elleder, Daniel

2014-10-04

A significant fraction of mammalian genomes is composed of endogenous retroviral (ERV) sequences that are formed by germline infiltration of various retroviruses. In contrast to other retroviral genera, lentiviruses only rarely form ERV copies. We performed a computational search aimed at identification of novel endogenous lentiviruses in vertebrate genomes. Using the in silico strategy, we have screened 104 publicly available vertebrate genomes for the presence of endogenous lentivirus sequences. In addition to the previously described cases, the search revealed the presence of endogenous lentivirus in the genome of Malayan colugo (Galeopterus variegatus). At least three complete copies of this virus, denoted ELVgv, were detected in the colugo genome, and approximately one hundred solo LTR sequences. The assembled consensus sequence of ELVgv had typical lentivirus genome organization including three predicted accessory genes. Phylogenetic analysis placed this virus as a distinct subgroup within the lentivirus genus. The time of insertion into the dermopteran lineage was estimated to be more than thirteen million years ago. We report the discovery of the first endogenous lentivirus in the mammalian order Dermoptera, which is a taxon close to the Primates. Lentiviruses have infiltrated the mammalian germline several times across millions of years. The colugo virus described here represents possibly the oldest documented endogenization event and its discovery can lead to new insights into lentivirus evolution. This is also the first report of an endogenous lentivirus in an Asian mammal, indicating a long-term presence of this retrovirus family in Asian continent.

Significance of major international seaports in the distribution of murine typhus in Taiwan

PubMed Central

Wardrop, Nicola; Chang, Chung-Te; Wang, Hsi-Chieh; Atkinson, Peter M.

2017-01-01

Background International seaports are hotspots for disease invasion and pathogens can persist in seaports even after ports are abandoned. Transmitted by fleas infected by Rickettsia typhi, murine typhus, a largely neglected and easily misdiagnosed disease, is known to occur primarily in large seaports. However, the significance of seaports in the occurrence of murine typhus has never been validated quantitatively. Methodology/Principal findings We studied the spatial distribution of murine typhus, a notifiable disease, in Taiwan. We investigated whether risk of infection was correlated with distance to international seaports and a collection of environmental and socioeconomic factors, using a Bayesian negative binomial conditionally autoregressive model, followed with geographically weighted regression. Seaports that are currently in use and those that operated in the 19th century for trade with China, but were later abandoned due to siltation were analyzed. A total of 476 human cases of murine typhus were reported during 2000–2014 in the main island of Taiwan, with spatial clustering in districts in southwest and central-west Taiwan. A higher incidence rate (case/population) was associated with a smaller distance to currently in-use international seaports and lower rainfall and temperature, but was uncorrelated with distance to abandoned ports. Geographically weighted regression revealed a geographic heterogeneity in the importance of distance to in-use seaports near the four international seaports of Taiwan. Conclusions/Significance Our study suggests that murine typhus is associated with international seaports, especially for those with large trading volume. Thus, one of the costs of global trade in Taiwan might be elevated risks of murine typhus. Globalization has accelerated the spread of infectious diseases, but the burden of disease varies geographically, with regions surrounding major international seaports warranting particular surveillance. PMID

Genomic alterations in spontaneous and carcinogen-induced murine melanoma cell lines.

PubMed

Melnikova, Vladislava O; Bolshakov, Svetlana V; Walker, Christopher; Ananthaswamy, Honnavara N

2004-03-25

We have conducted an analysis of genetic alterations in spontaneous murine melanoma cell line B16F0 and its two metastatic clones, B16F1 and B16F10 and the carcinogen-induced murine melanoma cell lines CM519, CM3205, and K1735. We found that unlike human melanomas, the murine melanoma cell lines did not have activating mutations in the Braf oncogene at exon 11 or 15. However, there were distinct patterns of alterations in the ras, Ink4a/Arf, and p53 genes in the two melanoma groups. In the spontaneous B16 melanoma cell lines, expression of p16Ink4a and p19Arf tumor suppressor proteins was lost as a consequence of a large deletion spanning Ink4a/Arf exons 1alpha, 1beta, and 2. In contrast, the carcinogen-induced melanoma cell lines expressed p16Ink4a but had inactivating mutations in either p19Arf (K1735) or p53 (CM519 and CM3205). Inactivation of p19Arf or p53 in carcinogen-induced melanomas was accompanied by constitutive activation of mitogen-activated protein kinases (MAPKs) and/or mutation-associated activation of N-ras. These results indicate that genetic alterations in p16Ink4a/p19Arf, p53 and ras-MAPK pathways can cooperate in the development of murine melanoma.

Inhibition of endogenous phosphodiesterase 7 promotes oligodendrocyte precursor differentiation and survival.

PubMed

Medina-Rodríguez, E M; Arenzana, F J; Pastor, J; Redondo, M; Palomo, V; García de Sola, R; Gil, C; Martínez, A; Bribián, A; de Castro, F

2013-09-01

During the development of the central nervous system (CNS), oligodendrocyte precursors (OPCs) are generated in specific sites within the neural tube and then migrate to colonize the entire CNS, where they differentiate into myelin-forming oligodendrocytes. Demyelinating diseases such as multiple sclerosis (MS) are characterized by the death of these cells. The CNS reacts to demyelination and by promoting spontaneous remyelination, an effect mediated by endogenous OPCs, cells that represent approximately 5-7 % of the cells in the adult brain. Numerous factors influence oligodendrogliogenesis and oligodendrocyte differentiation, including morphogens, growth factors, chemotropic molecules, extracellular matrix proteins, and intracellular cAMP levels. Here, we show that during development and in early adulthood, OPCs in the murine cerebral cortex contain phosphodiesterase-7 (PDE7) that metabolizes cAMP. We investigated the effects of different PDE7 inhibitors (the well-known BRL-50481 and two new ones, TC3.6 and VP1.15) on OPC proliferation, survival, and differentiation. While none of the PDE7 inhibitors analyzed altered OPC proliferation, TC3.6 and VP1.15 enhanced OPC survival and differentiation, processes in which ERK intracellular signaling played a key role. PDE7 expression was also observed in OPCs isolated from adult human brains and the differentiation of these OPCs into more mature oligodendroglial phenotypes was accelerated by treatment with both new PDE7 inhibitors. These findings reveal new roles for PDE7 in regulating OPC survival and differentiation during brain development and in adulthood, and they may further our understanding of myelination and facilitate the development of therapeutic remyelination strategies for the treatment of MS.

Recruiting endogenous stem cells: a novel therapeutic approach for erectile dysfunction

PubMed Central

Xin, Zhong-Cheng; Xu, Yong-De; Lin, Guiting; Lue, Tom F; Guo, Ying-Lu

2016-01-01

Transplanted stem cells (SCs), owing to their regenerative capacity, represent one of the most promising methods to restore erectile dysfunction (ED). However, insufficient source, invasive procedures, ethical and regulatory issues hamper their use in clinical applications. The endogenous SCs/progenitor cells resident in organ and tissues play critical roles for organogenesis during development and for tissue homeostasis in adulthood. Even without any therapeutic intervention, human body has a robust self-healing capability to repair the damaged tissues or organs. Therefore, SCs-for-ED therapy should not be limited to a supply-side approach. The resident endogenous SCs existing in patients could also be a potential target for ED therapy. The aim of this review was to summarize contemporary evidence regarding: (1) SC niche and SC biological features in vitro; (2) localization and mobilization of endogenous SCs; (3) existing evidence of penile endogenous SCs and their possible mode of mobilization. We performed a search on PubMed for articles related to these aspects in a wide range of basic studies. Together, numerous evidences hold the promise that endogenous SCs would be a novel therapeutic approach for the therapy of ED. PMID:25926601

1.8 Astroms Structure of Murine GITR Ligand Dimer Expressed in Drosophila Melanogaster S2 Cells

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

Chattopadhyay, K.; Ramagopal, U; Nathenson, S

2009-01-01

Glucocorticoid-induced TNF receptor ligand (GITRL), a prominent member of the TNF superfamily, activates its receptor on both effector and regulatory T cells to generate critical costimulatory signals that have been implicated in a wide range of T-cell immune functions. The crystal structures of murine and human orthologs of GITRL recombinantly expressed in Escherichia coli have previously been determined. In contrast to all classical TNF structures, including the human GITRL structure, murine GITRL demonstrated a unique 'strand-exchanged' dimeric organization. Such a novel assembly behavior indicated a dramatic impact on receptor activation as well as on the signaling mechanism associated with themore » murine GITRL costimulatory system. In this present work, the 1.8 {angstrom} resolution crystal structure of murine GITRL expressed in Drosophila melanogaster S2 cells is reported. The eukaryotic protein-expression system allows transport of the recombinant protein into the extracellular culture medium, thus maximizing the possibility of obtaining correctly folded material devoid of any folding/assembly artifacts that are often suspected with E. coli-expressed proteins. The S2 cell-expressed murine GITRL adopts an identical 'strand-exchanged' dimeric structure to that observed for the E. coli-expressed protein, thus conclusively demonstrating the novel quaternary structure assembly behavior of murine GITRL.« less

Biomechanical Properties of Murine Meniscus Surface via AFM-based Nanoindentation

PubMed Central

Li, Qing; Doyran, Basak; Gamer, Laura W.; Lu, X. Lucas; Qin, Ling; Ortiz, Christine; Grodzinsky, Alan J.; Rosen, Vicki; Han, Lin

2015-01-01

This study aimed to quantify the biomechanical properties of murine meniscus surface. Atomic force microscopy (AFM)-based nanoindentation was performed on the central region, proximal side of menisci from 6- to 24-week old male C57BL/6 mice using microspherical tips (Rtip ≈ 5 μm) in PBS. A unique, linear correlation between indentation depth, D, and response force, F, was found on menisci from all age groups. This non-Hertzian behavior is likely due to the dominance of tensile resistance by the collagen fibril bundles on meniscus surface that are mostly aligned along the circumferential direction observed on 12-week old menisci. The indentation resistance was calculated as both the effective stiffness, Sind = dF/dD, and the effective modulus, Eind, via the isotropic Hertz model. Values of Sind and Eind were found to depend on indentation rate, suggesting the existence of poro-viscoelasticity. These values do not significantly vary with anatomical sites, lateral versus medial compartments, or mouse age. In addition, Eind of meniscus surface (e.g., 6.1 ± 0.8 MPa for 12 weeks of age, mean ± SEM, n = 13) was found to be significantly higher than those of meniscus surfaces in other species, and of murine articular cartilage surface (1.4 ± 0.1 MPa, n = 6). In summary, these results provided the first direct mechanical knowledge of murine knee meniscus tissues. We expect this understanding to serve as a mechanics-based benchmark for further probing the developmental biology and osteoarthritis symptoms of meniscus in various murine models. PMID:25817332

Protection from experimental asthma by an endogenous bronchodilator.

PubMed

Que, Loretta G; Liu, Limin; Yan, Yun; Whitehead, Gregory S; Gavett, Stephen H; Schwartz, David A; Stamler, Jonathan S

2005-06-10

Mechanisms that protect against asthma remain poorly understood. S-nitrosoglutathione (GSNO), an endogenous bronchodilator, is depleted from asthmatic airways, suggesting a protective role. We report that, following allergen challenge, wild-type mice exhibiting airway hyperresponsivity have increased airway levels of the enzyme GSNO reductase (GSNOR) and are depleted of lung S-nitrosothiols (SNOs). In contrast, mice with genetic deletion of GSNOR exhibit increases in lung SNOs and are protected from airway hyperresponsivity. Our results indicate that endogenous SNOs, governed by GSNOR, are critical regulators of airway responsivity and may provide new therapeutic approaches to asthma.

Severe interstitial pneumonia due to murine typhus in a patient returning from Bali.

PubMed

Malheiro, Luís; Ceia, Filipa; Alves, João; Carvalho, Ana Cláudia; Sobrinho-Simões, Joana; Sousa, Rita; Sarmento, António; Santos, Lurdes

2017-01-01

Murine typhus has been increasingly reported as a cause of fever in returning travelers from Southeast Asia. We report a case of a previously healthy traveler returning from Bali with an non-specific febrile illness which quickly progressed to a severe form of interstitial pneumonia. After a careful epidemiological evaluation and laboratory analysis, murine typhus was diagnosed.

[Virulence of Sporothrix globosa in murine models].

PubMed

Cruz Choappa, Rodrigo; Pérez Gaete, Salomón; Rodríguez Badilla, Valentina; Vieille Oyarzo, Peggy; Opazo Sanchez, Héctor

The sporothricosis disease is an infection caused by species included in Sporothrix schenkii complex. Verify the virulence of a strain of S. globosa using two different concentrations of inoculum by intraperitoneally and subcutaneously, into a mouse model. Nonrandomized pilot study, in murine inoculated with a strain of S. globosa (CBS 14.076M) by intraperitoneally and subcutaneously with inoculum concentrations of 0.5 and 4 McFarland. For this purpose 18 rodents CF-1 (ISP, Santiago, Chile) were used. The studied strain did not induce illness or injury on animals, they all survived and neither the tissue culture nor the histopathological analysis showed fungal growth or suggestive infection by organ abnormalities. The S. globosa strain did not present any virulence enough to cause disease at 0.5 and 4.0 McFarland concentration inoculum when inoculated in both intraperitoneally and subcutaneously, in murine models. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Gastrointestinal Endogenous Proteins as a Source of Bioactive Peptides - An In Silico Study

PubMed Central

Dave, Lakshmi A.; Montoya, Carlos A.; Rutherfurd, Shane M.; Moughan, Paul J.

2014-01-01

Dietary proteins are known to contain bioactive peptides that are released during digestion. Endogenous proteins secreted into the gastrointestinal tract represent a quantitatively greater supply of protein to the gut lumen than those of dietary origin. Many of these endogenous proteins are digested in the gastrointestinal tract but the possibility that these are also a source of bioactive peptides has not been considered. An in silico prediction method was used to test if bioactive peptides could be derived from the gastrointestinal digestion of gut endogenous proteins. Twenty six gut endogenous proteins and seven dietary proteins were evaluated. The peptides present after gastric and intestinal digestion were predicted based on the amino acid sequence of the proteins and the known specificities of the major gastrointestinal proteases. The predicted resultant peptides possessing amino acid sequences identical to those of known bioactive peptides were identified. After gastrointestinal digestion (based on the in silico simulation), the total number of bioactive peptides predicted to be released ranged from 1 (gliadin) to 55 (myosin) for the selected dietary proteins and from 1 (secretin) to 39 (mucin-5AC) for the selected gut endogenous proteins. Within the intact proteins and after simulated gastrointestinal digestion, angiotensin converting enzyme (ACE)-inhibitory peptide sequences were the most frequently observed in both the dietary and endogenous proteins. Among the dietary proteins, after in silico simulated gastrointestinal digestion, myosin was found to have the highest number of ACE-inhibitory peptide sequences (49 peptides), while for the gut endogenous proteins, mucin-5AC had the greatest number of ACE-inhibitory peptide sequences (38 peptides). Gut endogenous proteins may be an important source of bioactive peptides in the gut particularly since gut endogenous proteins represent a quantitatively large and consistent source of protein. PMID:24901416

Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy

PubMed Central

Di Sante, Gabriele; Casimiro, Mathew C.; Pestell, Timothy G.; Pestell, Richard G.

2016-01-01

Time-lapse video microscopy can be defined as the real time imaging of living cells. This technique relies on the collection of images at different time points. Time intervals can be set through a computer interface that controls the microscope-integrated camera. This kind of microscopy requires both the ability to acquire very rapid events and the signal generated by the observed cellular structure during these events. After the images have been collected, a movie of the entire experiment is assembled to show the dynamic of the molecular events of interest. Time-lapse video microscopy has a broad range of applications in the biomedical research field and is a powerful and unique tool for following the dynamics of the cellular events in real time. Through this technique, we can assess cellular events such as migration, division, signal transduction, growth, and death. Moreover, using fluorescent molecular probes we are able to mark specific molecules, such as DNA, RNA or proteins and follow them through their molecular pathways and functions. Time-lapse video microscopy has multiple advantages, the major one being the ability to collect data at the single-cell level, that make it a unique technology for investigation in the field of cell biology. However, time-lapse video microscopy has limitations that can interfere with the acquisition of high quality images. Images can be compromised by both external factors; temperature fluctuations, vibrations, humidity and internal factors; pH, cell motility. Herein, we describe a protocol for the dynamic acquisition of a specific protein, Parkin, fused with the enhanced yellow fluorescent protein (EYFP) in order to track the selective removal of damaged mitochondria, using a time-lapse video microscopy approach. PMID:27168174

Three-dimensional alginate spheroid culture system of murine osteosarcoma.

PubMed

Akeda, Koji; Nishimura, Akinobu; Satonaka, Haruhiko; Shintani, Ken; Kusuzaki, Katsuyuki; Matsumine, Akihiko; Kasai, Yuichi; Masuda, Koichi; Uchida, Atsumasa

2009-11-01

Osteosarcoma (OS) is the most common primary malignant tumor of the bone and often forms pulmonary metastases, which are the most important prognostic factor. For further elucidation of the mechanism underlying the progression and metastasis of human OS, a culture system mimicking the microenvironment of the tumor in vivo is needed. We report a novel three-dimensional (3D) alginate spheroid culture system of murine osteosarcoma. Two different metastatic clones, the parental Dunn and its derivative line LM8, which has a higher metastatic potential to the lungs, were encapsulated in alginate beads to develop the 3D culture system. The beads containing murine OS cells were also transplanted into mice to determine their metastatic potential in vivo. In this culture system, murine OS cells encapsulated in alginate beads were able to grow in a 3D structure with cells detaching from the alginate environment. The number of detaching cells was higher in the LM8 cell line than the Dunn cell line. In the in vivo alginate bead transplantation model, the rate of pulmonary metastasis was higher with LM8 cells compared with that of Dunn cells. The cell characteristics and kinetics in this culture system closely reflect the original malignant potential of the cells in vivo.

Evaluation of a Murine Single-Blood-Injection SAH Model

PubMed Central

Sommer, Clemens; Steiger, Hans-Jakob; Schneider, Toni; Hänggi, Daniel

2014-01-01

The molecular pathways underlying the pathogenesis after subarachnoid haemorrhage (SAH) are poorly understood and continue to be a matter of debate. A valid murine SAH injection model is not yet available but would be the prerequisite for further transgenic studies assessing the mechanisms following SAH. Using the murine single injection model, we examined the effects of SAH on regional cerebral blood flow (rCBF) in the somatosensory (S1) and cerebellar cortex, neuro-behavioural and morphological integrity and changes in quantitative electrocorticographic and electrocardiographic parameters. Micro CT imaging verified successful blood delivery into the cisterna magna. An acute impairment of rCBF was observed immediately after injection in the SAH and after 6, 12 and 24 hours in the S1 and 6 and 12 hours after SAH in the cerebellum. Injection of blood into the foramen magnum reduced telemetric recorded total ECoG power by an average of 65%. Spectral analysis of ECoGs revealed significantly increased absolute delta power, i.e., slowing, cortical depolarisations and changes in ripples and fast ripple oscillations 12 hours and 24 hours after SAH. Therefore, murine single-blood-injection SAH model is suitable for pathophysiological and further molecular analysis following SAH. PMID:25545775

Endogenous opiates and behavior: 2005.

PubMed

Bodnar, Richard J; Klein, Gad E

2006-12-01

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).

Endogenous opiates and behavior: 2010.

PubMed

Bodnar, Richard J

2011-12-01

This paper is the thirty-third consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2010 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17). Copyright © 2011 Elsevier Inc. All rights reserved.

Endogenous opiates and behavior: 2002.

PubMed

Bodnar, Richard J; Hadjimarkou, Maria M

2003-08-01

This paper is the twenty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2002 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Endogenous opiates and behavior: 2006.

PubMed

Bodnar, Richard J

2007-12-01

This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Endogenous opiates and behavior: 2009.

PubMed

Bodnar, Richard J

2010-12-01

This paper is the 32nd consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2009 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). Copyright © 2010 Elsevier Inc. All rights reserved.

Endogenous opiates and behavior: 2011.

PubMed

Bodnar, Richard J

2012-12-01

This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17). Copyright © 2012 Elsevier Inc. All rights reserved.

Endogenous opiates and behavior: 2003.

PubMed

Bodnar, Richard J; Klein, Gad E

2004-12-01

This paper is the 26th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2003 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Endogenous opiates and behavior: 2008.

PubMed

Bodnar, Richard J

2009-12-01

This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Endogenous Opiates and Behavior: 2006

PubMed Central

Bodnar, Richard J.

2009-01-01

This paper is the twenty-ninth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning thirty years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). PMID:17949854

Endogenous opiates and behavior: 2012.

PubMed

Bodnar, Richard J

2013-12-01

This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17). Copyright © 2013 Elsevier Inc. All rights reserved.

Neural correlates of endogenous attention, exogenous attention and inhibition of return in touch.

PubMed

Jones, Alexander; Forster, Bettina

2014-07-01

Selective attention helps process the myriad of information constantly touching our body. Both endogenous and exogenous mechanisms are relied upon to effectively process this information; however, it is unclear how they relate in the sense of touch. In three tasks we contrasted endogenous and exogenous event-related potential (ERP) and behavioural effects. Unilateral tactile cues were followed by a tactile target at the same or opposite hand. Clear behavioural effects showed facilitation of expected targets both when the cue predicted targets at the same (endogenous predictive task) and opposite hand (endogenous counter-predictive task), and these effects also correlated with ERP effects of endogenous attention. In an exogenous task, where the cue was non-informative, inhibition of return (IOR) was observed. The electrophysiological results demonstrated early effects of exogenous attention followed by later endogenous attention modulations. These effects were independent in both the endogenous predictive and exogenous tasks. However, voluntarily directing attention away from a cued body part influenced the early exogenous marker (N80). This suggests that the two mechanisms are interdependent, at least when the task requires more demanding shifts of attention. The early marker of exogenous tactile attention, the N80, was not directly related to IOR, which may suggest that exogenous attention and IOR are not necessarily two sides of the same coin. This study adds valuable new insight into how we process and select information presented to our body, showing both independent and interdependent effects of endogenous and exogenous attention in touch. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Endogenous sex steroids and cardio- and cerebro-vascular disease in the postmenopausal period.

PubMed

Pappa, Theodora; Alevizaki, Maria

2012-08-01

Cardio- and cerebro-vascular diseases are two leading causes of death and long-term disability in postmenopausal women. The acute fall of estrogen in menopause is associated with increased cardiovascular risk. The relative contribution of androgen to this risk is also being recognized. The use of more sensitive assays for estradiol measurement and the study of receptor and carrier protein gene polymorphisms have provided some new information on the clinical relevance of endogenous sex steroids. We provide an update on the role of endogenous sex steroids on cardio- and cerebro-vascular disease in the postmenopausal period. We performed a PubMed search using the terms 'endogenous estrogen', 'androgen', 'cardiovascular disease', 'cerebro-vascular disease', 'stroke', 'carotid artery disease', and 'subclinical atherosclerosis'. The majority of studies show a beneficial effect of endogenous estrogen on the vasculature; however, there are a few studies reporting the contrary. A significant body of literature has reported associations of endogenous estrogen and androgen with early markers of atherosclerosis and metabolic parameters. Data on the relevance of endogenous sex steroids in heart disease and stroke are inconclusive. Most studies support a beneficial role of endogenous estrogens and, probably, an adverse effect of androgens in the vasculature in postmenopausal women. However, the described associations may not always be considered as causal. It is possible that circulating estrogen might represent a marker of general health status or alternatively reflect the sum of endogenous androgens aromatized in the periphery. Elucidating the role of sex steroids in cardio- and cerebro-vascular disease remains an interesting field of future research.

Systematic Characterization of the Murine Mitochondrial Proteome Using Functionally Validated Cardiac Mitochondria

PubMed Central

Zhang, Jun; Li, Xiaohai; Mueller, Michael; Wang, Yueju; Zong, Chenggong; Deng, Ning; Vondriska, Thomas M.; Liem, David A.; Yang, Jeong-In; Korge, Paavo; Honda, Henry; Weiss, James N.; Apweiler, Rolf; Ping, Peipei

2009-01-01

Mitochondria play essential roles in cardiac pathophysiology and the murine model has been extensively used to investigate cardiovascular diseases. In the present study, we characterized murine cardiac mitochondria using an LC/MS/MS approach. We extracted and purified cardiac mitochondria; validated their functionality to ensure the final preparation contains necessary components to sustain their normal function; and subjected these validated organelles to LC/MS/MS-based protein identification. A total of 940 distinct proteins were identified from murine cardiac mitochondria, among which, 480 proteins were not previously identified by major proteomic profiling studies. The 940 proteins consist of functional clusters known to support oxidative phosphorylation, metabolism and biogenesis. In addition, there are several other clusters--including proteolysis, protein folding, and reduction/oxidation signaling-which ostensibly represent previously under-appreciated tasks of cardiac mitochondria. Moreover, many identified proteins were found to occupy other subcellular locations, including cytoplasm, ER, and golgi, in addition to their presence in the mitochondria. These results provide a comprehensive picture of the murine cardiac mitochondrial proteome and underscore tissue- and species-specification. Moreover, the use of functionally intact mitochondria insures that the proteomic observations in this organelle are relevant to its normal biology and facilitates decoding the interplay between mitochondria and other organelles. PMID:18348319

Effect of storage temperature on endogenous GHB levels in urine.

PubMed

LeBeau, M A; Miller, M L; Levine, B

2001-06-15

Because gamma-hydroxybutyrate (GHB) is an endogenous substance present in the body and is rapidly eliminated after ingestion, toxicologists investigating drug-facilitated sexual assault cases are often asked to differentiate between endogenous and exogenous levels of GHB in urine samples. This study was designed to determine the effects of storage temperature on endogenous GHB levels in urine. Specifically, it was designed to ascertain whether endogenous levels can be elevated to a range considered indicative of GHB ingestion. Urine specimens from two subjects that had not been administered exogenous GHB were collected during a 24h period and individually pooled. The pooled specimens were separated into standard sample cups and divided into three storage groups: room temperature ( approximately 25 degrees C), refrigerated (5 degrees C), and frozen (-10 degrees C). Additionally, some specimens were put through numerous freeze/thaw cycles to mimic situations that may occur if multiple laboratories analyze the same specimen. Periodic analysis of the samples revealed increases in the levels of endogenous GHB over a 6-month period. The greatest increase (up to 404%) was observed in the samples maintained at room temperature. The refrigerated specimens showed increases of 140-208%, while the frozen specimens showed smaller changes (88-116%). The specimens subjected to multiple freeze/thaw cycles mirrored specimens that had been thawed only once. None of the stored urine specimens demonstrated increases in GHB concentrations that would be consistent with exogenous GHB ingestion.

The Influence of Endogenous and Exogenous Spatial Attention on Decision Confidence.

PubMed

Kurtz, Phillipp; Shapcott, Katharine A; Kaiser, Jochen; Schmiedt, Joscha T; Schmid, Michael C

2017-07-25

Spatial attention allows us to make more accurate decisions about events in our environment. Decision confidence is thought to be intimately linked to the decision making process as confidence ratings are tightly coupled to decision accuracy. While both spatial attention and decision confidence have been subjected to extensive research, surprisingly little is known about the interaction between these two processes. Since attention increases performance it might be expected that confidence would also increase. However, two studies investigating the effects of endogenous attention on decision confidence found contradictory results. Here we investigated the effects of two distinct forms of spatial attention on decision confidence; endogenous attention and exogenous attention. We used an orientation-matching task, comparing the two attention conditions (endogenous and exogenous) to a control condition without directed attention. Participants performed better under both attention conditions than in the control condition. Higher confidence ratings than the control condition were found under endogenous attention but not under exogenous attention. This finding suggests that while attention can increase confidence ratings, it must be voluntarily deployed for this increase to take place. We discuss possible implications of this relative overconfidence found only during endogenous attention with respect to the theoretical background of decision confidence.

Mesenchymal stromal cell derived extracellular vesicles rescue radiation damage to murine marrow hematopoietic cells

PubMed Central

Wen, Sicheng; Dooner, Mark; Cheng, Yan; Papa, Elaine; Del Tatto, Michael; Pereira, Mandy; Deng, Yanhui; Goldberg, Laura; Aliotta, Jason; Chatterjee, Devasis; Stewart, Connor; Carpanetto, Andrea; Collino, Federica; Bruno, Stefania; Camussi, Giovanni; Quesenberry, Peter

2016-01-01

Mesenchymal stromal cells (MSC) have been shown to reverse radiation damage to marrow stem cells. We have evaluated the capacity of MSC-derived extracellular vesicles (MSC-EVs) to mitigate radiation injury to marrow stem cells at 4 hours to 7 days after irradiation. Significant restoration of marrow stem cell engraftment at 4, 24 and 168 hours post-irradiation by exposure to MSC-EVs was observed at 3 weeks to 9 months after transplant and further confirmed by secondary engraftment. Intravenous injection of MSC-EVs to 500cGy exposed mice led to partial recovery of peripheral blood counts and restoration of the engraftment of marrow. The murine hematopoietic cell line, FDC-P1 exposed to 500 cGy, showed reversal of growth inhibition, DNA damage and apoptosis on exposure to murine or human MSC-EVs. Both murine and human MSC-EVs reverse radiation damage to murine marrow cells and stimulate normal murine marrow stem cell/progenitors to proliferate. A preparation with both exosomes and microvesicles was found to be superior to either microvesicles or exosomes alone. Biologic activity was seen in freshly isolated vesicles and in vesicles stored for up to 6 months in 10% DMSO at −80°C. These studies indicate that MSC-EVs can reverse radiation damage to bone marrow stem cells. PMID:27150009

Microbial endogenous response to acute inhibitory impact of antibiotics.

PubMed

Pala-Ozkok, I; Kor-Bicakci, G; Çokgör, E U; Jonas, D; Orhon, D

2017-06-13

Enhanced endogenous respiration was observed as the significant/main response of the aerobic microbial culture under pulse exposure to antibiotics: sulfamethoxazole, tetracycline and erythromycin. Peptone mixture and acetate were selected as organic substrates to compare the effect of complex and simple substrates. Experiments were conducted with microbial cultures acclimated to different sludge ages of 10 and 2 days, to visualize the effect of culture history. Evaluation relied on modeling of oxygen uptake rate profiles, reflecting the effect of all biochemical reactions associated with substrate utilization. Model calibration exhibited significant increase in values of endogenous respiration rate coefficient with all antibiotic doses. Enhancement of endogenous respiration was different with antibiotic type and initial dose. Results showed that both peptone mixture and acetate cultures harbored resistance genes against the tested antibiotics, which suggests that biomass spends cellular maintenance energy for activating the required antibiotic resistance mechanisms to survive, supporting higher endogenous decay rates. [Formula: see text]: maximum growth rate for X H (day -1 ); K S : half saturation constant for growth of X H (mg COD/L); b H : endogenous decay rate for X H (day -1 ); k h : maximum hydrolysis rate for S H1 (day -1 ); K X : hydrolysis half saturation constant for S H1 (mg COD/L); k hx : maximum hydrolysis rate for X S1 (day -1 ); K XX : hydrolysis half saturation constant for X S1 (mg COD/L); k STO : maximum storage rate of PHA by X H (day -1 ); [Formula: see text]: maximum growth rate on PHA for X H (day -1 ); K STO : half saturation constant for storage of PHA by X H (mg COD/L); X H1 : initial active biomass (mg COD/L).

Multi-spectral endogenous fluorescence imaging for bacterial differentiation

NASA Astrophysics Data System (ADS)

Chernomyrdin, Nikita V.; Babayants, Margarita V.; Korotkov, Oleg V.; Kudrin, Konstantin G.; Rimskaya, Elena N.; Shikunova, Irina A.; Kurlov, Vladimir N.; Cherkasova, Olga P.; Komandin, Gennady A.; Reshetov, Igor V.; Zaytsev, Kirill I.

2017-07-01

In this paper, the multi-spectral endogenous fluorescence imaging was implemented for bacterial differentiation. The fluorescence imaging was performed using a digital camera equipped with a set of visual bandpass filters. Narrowband 365 nm ultraviolet radiation passed through a beam homogenizer was used to excite the sample fluorescence. In order to increase a signal-to-noise ratio and suppress a non-fluorescence background in images, the intensity of the UV excitation was modulated using a mechanical chopper. The principal components were introduced for differentiating the samples of bacteria based on the multi-spectral endogenous fluorescence images.

Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation.

PubMed Central

Trojan, J; Johnson, T R; Rudin, S D; Blossey, B K; Kelley, K M; Shevelev, A; Abdul-Karim, F W; Anthony, D D; Tykocinski, M L; Ilan, J

1994-01-01

Teratocarcinoma is a germ-line carcinoma giving rise to an embryoid tumor with structures derived from the three embryonic layers: mesoderm, endoderm, and ectoderm. Teratocarcinoma is widely used as an in vitro model system to study regulation of cell determination and differentiation during mammalian embryogenesis. Murine embryonic carcinoma (EC) PCC3 cells express insulin-like growth factor I(IGF-I) and its receptor, while all derivative tumor structures express IGF-I and IGF-II and their receptors. Therefore the system lends itself to dissect the role of these two growth factors during EC differentiation. With an episomal antisense strategy, we define a role for IGF-I in tumorigenicity and evasion of immune surveillance. Antisense IGF-I EC transfectants are shown to elicit a curative anti-tumor immune response with tumor regression at distal sites. In contrast, IGF-II is shown to drive determination and differentiation in EC cells. Since IGF-I and IGF-II bind to type I receptor and antisense sequence used for IGF-II cannot form duplex with endogenous IGF-I transcripts, it follows that this receptor is not involved in determination and differentiation. Images PMID:8016120

Integrin Based Isolation Enables Purification of Murine Lineage Committed Cardiomyocytes

PubMed Central

Tarnawski, Laura; Xian, Xiaojie; Monnerat, Gustavo; Macaulay, Iain C.; Malan, Daniela; Borgman, Andrew; Wu, Sean M.; Fleischmann, Bernd K.; Jovinge, Stefan

2015-01-01

In contrast to mature cardiomyocytes which have limited regenerative capacity, pluripotent stem cells represent a promising source for the generation of new cardiomyocytes. The tendency of pluripotent stem cells to form teratomas and the heterogeneity from various differentiation stages and cardiomyocyte cell sub-types, however, are major obstacles to overcome before this type of therapy could be applied in a clinical setting. Thus, the identification of extracellular markers for specific cardiomyocyte progenitors and mature subpopulations is of particular importance. The delineation of cardiomyocyte surface marker patterns not only serves as a means to derive homogeneous cell populations by FACS, but is also an essential tool to understand cardiac development. By using single-cell expression profiling in early mouse embryonic hearts, we found that a combination of integrin alpha-1, alpha-5, alpha-6 and N-cadherin enables isolation of lineage committed murine cardiomyocytes. Additionally, we were able to separate trabecular cardiomyocytes from solid ventricular myocardium and atrial murine cells. These cells exhibit expected subtype specific phenotype confirmed by electrophysiological analysis. We show that integrin expression can be used for the isolation of living, functional and lineage-specific murine cardiomyocytes. PMID:26323090

[Effects of traditional tibetan medicine, Fructus Lonicerae microphyllae on phagecytosis and cytokines production of murine macrophages].

PubMed

Wang, Ju-Le; Sun, Yang; Zhou, Hui-Ying; Xu, Qiang; Dun, Zhu

2006-01-01

To explore the effects of traditional Tibetan medicine, Fructus Lonicerae microphyllae (FLM) on phagecytosis and cytokines production of murine macrophages. The phagecytosis of murine macrophages was analyzed by neutral red phagecytosis assay. The activities of IL-1 and TNF-alpha were measured by biological methods. The mRNA of TNF-alpha and INF-gamma expressed by macrophages was detected by RT-PCR. The phagecytosis of murine macrophages was significantly enhanced by FLM at a concentration from 1 microg x mL(-1) to 100 microg x mL(-1) and the secretions of IL-1, and TNF-alpha from macrophages were markedly induced by FLM. Meanwhile, FLM also increased the expression of TNF-alpha mRNA and INF-gamma mRHA from macrophages in vitro. FLM could promote phagecytosis and cytokines production of murine macrophages.

A model of the endogenous glucose balance incorporating the characteristics of glucose transporters.

PubMed

Arleth, T; Andreassen, S; Federici, M O; Benedetti, M M

2000-07-01

This paper describes the development and preliminary test of a model of the endogenous glucose balance that incorporates the characteristics of the glucose transporters GLUT1, GLUT3 and GLUT4. In the modeling process the model is parameterized with nine parameters that are subsequently estimated from data in the literature on the hepatic- and endogenous- balances at various combinations of blood glucose and insulin levels. The ability of the resulting endogenous balance to fit blood glucose measured from patients was tested on 20 patients. The fit obtained with this model compared favorably with the fit obtained with the endogenous balance currently incorporated in the DIAS system.

Magnetic resonance imaging and spectroscopy of the murine cardiovascular system.

PubMed

Akki, Ashwin; Gupta, Ashish; Weiss, Robert G

2013-03-01

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease.

Endogenous mitigation of H2S inside of the landfills.

PubMed

Fang, Yuan; Zhong, Zhong; Shen, Dongsheng; Du, Yao; Xu, Jing; Long, Yuyang

2016-02-01

Vast quantities of hydrogen sulfide (H2S) emitted from landfill sites require urgent disposal. The current study focused on source control and examined the migration and conversion behavior of sulfur compounds in two lab-scale simulated landfills with different operation modes. It aimed to explore the possible strategies and mechanisms for H2S endogenous mitigation inside of landfills during decomposition. It was found that the strength of H2S emissions from the landfill sites was dependent on the municipal solid waste (MSW) degradation speed and vertical distribution of sulfide. Leachate recirculation can shorten both the H2S influence period and pollution risk to the surrounding environment. H2S endogenous mitigation may be achieved by chemical oxidation, biological oxidation, adsorption, and/or precipitation in different stages. Migration and conversion mainly affected H2S release behavior during the initial stabilization phase in the landfill. Microbial activities related to sulfur, nitrogen, and iron can further promote H2S endogenous mitigation during the high reducing phase. Thus, H2S endogenous mitigation can be effectively enhanced via control of the aforementioned processes.

Guidance of spatial attention by incidental learning and endogenous cuing

PubMed Central

Jiang, Yuhong V.; Swallow, Khena M.; Rosenbaum, Gail M.

2012-01-01

Our visual system is highly sensitive to regularities in the environment. Locations that were important in one’s previous experience are often prioritized during search, even though observers may not be aware of the learning. In this study we characterized the guidance of spatial attention by incidental learning of a target’s spatial probability, and examined the interaction between endogenous cuing and probability cuing. Participants searched for a target (T) among distractors (L’s). The target was more often located in one region of the screen than in others. We found that search RT was faster when the target appeared in the high-frequency region rather than the low-frequency regions. This difference increased when there were more items on the display, suggesting that probability cuing guides spatial attention. Additional data indicated that on their own, probability cuing and endogenous cuing (e.g., a central arrow that predicted a target’s location) were similarly effective at guiding attention. However, when both cues were presented at once, probability cuing was largely eliminated. Thus, although both incidental learning and endogenous cuing can effectively guide attention, endogenous cuing takes precedence over incidental learning. PMID:22506784

Role of Endogenous Cholecystokinin on Growth of Human Pancreatic Cancer

PubMed Central

Matters, Gail L.; McGovern, Christopher; Harms, John F.; Markovic, Kevin; Anson, Krystal; Jayakumar, Calpurnia; Martenis, Melissa; Awad, Christina; Smith, Jill P.

2012-01-01

Cholecystokinin (CCK) and gastrin stimulate growth of pancreatic cancer. Although down regulation of gastrin inhibits growth of pancreatic cancer, the contribution of endogenous CCK to tumor growth is unknown. The purpose of this study was to evaluate the role of endogenous CCK on autocrine growth of pancreatic cancer. Pancreatic cancer cell lines were analyzed for CCK mRNA and peptide expression by real time RT-PCR and radioimmunoassay, respectively. The effect of endogenous CCK on growth was evaluated by treating cancer cells with CCK neutralizing antibodies and by down regulating CCK mRNA by RNAi. Wild type pancreatic cancer cells expressed significantly lower CCK mRNA and peptide levels than gastrin. Neither treatment of pancreatic cancer cells with CCK antibodies nor the down regulation of CCK mRNA and peptide by shRNAs altered growth in vitro or in vivo. Conversely, when gastrin mRNA expression was down regulated, the same cells failed to produce tumors in spite of having sustained levels of endogenous CCK. Pancreatic cancer cells produce CCK and gastrin; however, the autocrine production of gastrin is more important for stimulating tumor growth. PMID:21186400

Conditions for Effective Application of Analysis of Symmetrically-Predicted Endogenous Subgroups

ERIC Educational Resources Information Center

Peck, Laura R.

2015-01-01

Several analytic strategies exist for opening up the "black box" to reveal more about what drives policy and program impacts. This article focuses on one of these strategies: the Analysis of Symmetrically-Predicted Endogenous Subgroups (ASPES). ASPES uses exogenous baseline data to identify endogenously-defined subgroups, keeping the…

Opioid glycopeptide analgesics derived from endogenous enkephalins and endorphins

PubMed Central

Li, Yingxue; Lefever, Mark R; Muthu, Dhanasekaran; Bidlack, Jean M; Bilsky, Edward J; Polt, Robin

2012-01-01

Over the past two decades, potent and selective analgesics have been developed from endogenous opioid peptides. Glycosylation provides an important means of modulating interaction with biological membranes, which greatly affects the pharmacodynamics and pharmacokinetics of the resulting glycopeptide analogues. Furthermore, manipulation of the membrane affinity allows penetration of cellular barriers that block efficient drug distribution, including the blood–brain barrier. Extremely potent and selective opiate agonists have been developed from endogenous peptides, some of which show great promise as drug candidates. PMID:22300099

Excretion of endogenous boldione in human urine: influence of phytosterol consumption.

PubMed

Verheyden, Karolien; Noppe, Herlinde; Vanhaecke, Lynn; Wille, Klaas; Bussche, Julie Vanden; Bekaert, Karen; Thas, Olivier; Janssen, Colin R; De Brabander, Hubert F

2009-10-01

Boldenone (17-hydroxy-androsta-1,4-diene-3-one, Bol) and boldione (androst-1,4-diene-3,17-dione, ADD), are currently listed as exogenous anabolic steroids by the World Anti-Doping Agency. However, it has been reported that these analytes can be produced endogenously. Interestingly, only for Bol a comment is included in the list on its potential endogenous origin. In this study, the endogenous origin of ADD in human urine was investigated, and the potential influence of phytosterol consumption was evaluated. We carried out a 5-week in vivo trial with both men (n=6) and women (n=6) and measured alpha-boldenone, beta-boldenone, boldione, androstenedione, beta-testosterone and alpha-testosterone in their urine using gas chromatography coupled to multiple mass spectrometry (GC-MS-MS). The results demonstrate that endogenous ADD is sporadically produced at concentrations ranging from 0.751 ng mL(-1) to 1.73 ng mL(-1), whereas endogenous Bol could not be proven. We also tested the effect of the daily consumption of a commercially available phytosterol-enriched yogurt drink on the presence of these analytes in human urine. Results from this study could not indicate a relation of ADD-excretion with the consumption of phytosterols at the recommended dose. The correlations between ADD and other steroids were consistently stronger for volunteers consuming phytosterols (test) than for those refraining from phytosterol consumption (control). Excretion of AED, bT and aT did not appear to be dependent on the consumption of phytosterols. This preliminary in vivo trial indicates the endogenous origin of boldione or ADD in human urine, independent on the presence of any structural related analytes such as phytosterols.

Novel Application of Micro-Computerized Tomography for Morphologic Characterization of the Murine Penis.

PubMed

O'Neill, Marisol; Huang, Gene O; Lamb, Dolores J

2017-12-01

The murine penis model has enriched our understanding of anomalous penile development. The morphologic characterization of the murine penis using conventional serial sectioning methods is labor intensive and prone to errors. To develop a novel application of micro-computerized tomography (micro-CT) with iodine staining for rapid, non-destructive morphologic study of murine penis structure. Penises were dissected from 10 adult wild-type mice and imaged using micro-CT with iodine staining. Images were acquired at 5-μm spatial resolution on a Bruker SkyScan 1272 micro-CT system. After images were acquired, the specimens were washed of any remaining iodine and embedded in paraffin for conventional histologic examination. Histologic and micro-CT measurements for all specimens were made by 2 independent observers. Measurements of penile structures were made on virtual micro-CT sections and histologic slides. The Lin concordance correlation coefficient demonstrated almost perfect strength of agreement for interobserver variability for histologic section (0.9995, 95% CI = 0.9990-0.9997) and micro-CT section (0.9982, 95% CI = 0.9963-0.9991) measurements. Bland-Altman analysis for agreement between the 2 modalities of measurement demonstrated mean differences of -0.029, 0.022, and -0.068 mm for male urogenital mating protuberance, baculum, and penile glans length, respectively. There did not appear to be a bias for overestimation or underestimation of measured lengths and limits of agreement were narrow. The enhanced ability offered by micro-CT to phenotype the murine penis has the potential to improve translational studies examining the molecular pathways contributing to anomalous penile development. The present study describes the first reported use of micro-CT with iodine staining for imaging the murine penis. Producing repeated histologic sections of identical orientation was limited by inherent imperfections in mounting and tissue sectioning, but this was

Endogenous subclinical hyperthyroidism and cardiovascular system: time to reconsider?

PubMed

Patanè, Salvatore; Marte, Filippo; Sturiale, Mauro

2011-05-19

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. Exogenous sublinical hyperthyroidism is a thyroid metabolic state caused by L-thyroxine administration. Endogenous subclinical hyperthyroidism is a thyroid metabolic state in patients with autonomously functioning thyroid nodule or multinodular goiter, various forms of thyroiditis, in areas with endemic goiter and particularly in elderly subjects. Endogenous subclinical hyperthyroidism is currently the subject of numerous studies and it yet remains controversial particularly as it relates to its treatment and to cardiovascular impact nevertheless established effects have been demonstrated. Recently, acute myocardial infarction without significant coronary stenoses and recurrent acute pulmonary embolism have been reported associated with subclinical hyperthyroidism without L-thyroxine administration. So, it is very important to recognize and to treat promptly also endogenous subclinical hyperthyroidism. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Identification of Components of the Murine Histone Deacetylase 6 Complex: Link between Acetylation and Ubiquitination Signaling Pathways

PubMed Central

Seigneurin-Berny, Daphné; Verdel, André; Curtet, Sandrine; Lemercier, Claudie; Garin, Jérôme; Rousseaux, Sophie; Khochbin, Saadi

2001-01-01

The immunopurification of the endogenous cytoplasmic murine histone deacetylase 6 (mHDAC6), a member of the class II HDACs, from mouse testis cytosolic extracts allowed the identification of two associated proteins. Both were mammalian homologues of yeast proteins known to interact with each other and involved in the ubiquitin signaling pathway: p97/VCP/Cdc48p, a homologue of yeast Cdc48p, and phospholipase A2-activating protein, a homologue of yeast UFD3 (ubiquitin fusion degradation protein 3). Moreover, in the C-terminal region of mHDAC6, a conserved zinc finger-containing domain named ZnF-UBP, also present in several ubiquitin-specific proteases, was discovered and was shown to mediate the specific binding of ubiquitin by mHDAC6. By using a ubiquitin pull-down approach, nine major ubiquitin-binding proteins were identified in mouse testis cytosolic extracts, and mHDAC6 was found to be one of them. All of these findings strongly suggest that mHDAC6 could be involved in the control of protein ubiquitination. The investigation of biochemical properties of the mHDAC6 complex in vitro further supported this hypothesis and clearly established a link between protein acetylation and protein ubiquitination. PMID:11689694

TCDD and a putative endogenous AhR ligand, ITE, elicit the same immediate changes in gene expression in mouse lung fibroblasts.

PubMed

Henry, Ellen C; Welle, Stephen L; Gasiewicz, Thomas A

2010-03-01

The aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, mediates toxicity of several classes of xenobiotics and also has important physiological roles in differentiation, reproduction, and immunity, although the endogenous ligand(s) mediating these functions is/are as yet unidentified. One candidate endogenous ligand, 2-(1'H-indolo-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), is a potent AhR agonist in vitro, activates the murine AhR in vivo, but does not induce toxicity. We hypothesized that ITE and the toxic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may modify transcription of different sets of genes to account for their different toxicity. To test this hypothesis, primary mouse lung fibroblasts were exposed to 0.5muM ITE, 0.2nM TCDD, or vehicle for 4 h, and total gene expression was evaluated using microarrays. After this short-term and low-dose treatment, several hundred genes were changed significantly, and the response to ITE and TCDD was remarkably similar, both qualitatively and quantitatively. Induced gene sets included the expected battery of AhR-dependent xenobiotic-metabolizing enzymes, as well as several sets that reflect the inflammatory role of lung fibroblasts. Real time quantitative RT-qPCR assay of several selected genes confirmed these microarray data and further suggested that there may be kinetic differences in expression between ligands. These data suggest that ITE and TCDD elicit an analogous change in AhR conformation such that the initial transcription response is the same. Furthermore, if the difference in toxicity between TCDD and ITE is mediated by differences in gene expression, then it is likely that secondary changes enabled by the persistent TCDD, but not by the shorter lived ITE, are responsible.

TCDD and a Putative Endogenous AhR Ligand, ITE, Elicit the Same Immediate Changes in Gene Expression in Mouse Lung Fibroblasts

PubMed Central

Henry, Ellen C.; Welle, Stephen L.; Gasiewicz, Thomas A.

2010-01-01

The aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, mediates toxicity of several classes of xenobiotics and also has important physiological roles in differentiation, reproduction, and immunity, although the endogenous ligand(s) mediating these functions is/are as yet unidentified. One candidate endogenous ligand, 2-(1′H-indolo-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), is a potent AhR agonist in vitro, activates the murine AhR in vivo, but does not induce toxicity. We hypothesized that ITE and the toxic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may modify transcription of different sets of genes to account for their different toxicity. To test this hypothesis, primary mouse lung fibroblasts were exposed to 0.5μM ITE, 0.2nM TCDD, or vehicle for 4 h, and total gene expression was evaluated using microarrays. After this short-term and low-dose treatment, several hundred genes were changed significantly, and the response to ITE and TCDD was remarkably similar, both qualitatively and quantitatively. Induced gene sets included the expected battery of AhR-dependent xenobiotic-metabolizing enzymes, as well as several sets that reflect the inflammatory role of lung fibroblasts. Real time quantitative RT-qPCR assay of several selected genes confirmed these microarray data and further suggested that there may be kinetic differences in expression between ligands. These data suggest that ITE and TCDD elicit an analogous change in AhR conformation such that the initial transcription response is the same. Furthermore, if the difference in toxicity between TCDD and ITE is mediated by differences in gene expression, then it is likely that secondary changes enabled by the persistent TCDD, but not by the shorter lived ITE, are responsible. PMID:19933214

A novel murine model for evaluating bovine papillomavirus prophylactics/therapeutics for equine sarcoid-like tumours

PubMed Central

Bogaert, Lies; Woodham, Andrew W.; Da Silva, Diane M.; Martens, Ann; Meyer, Evelyne

2015-01-01

Equine sarcoids are highly recurrent bovine papillomavirus (BPV)-induced fibroblastic neoplasms that are the most common skin tumours in horses. In order to facilitate the study of potential equine sarcoid prophylactics or therapeutics, which can be a slow and costly process in equines, a murine model for BPV-1 protein-expressing equine sarcoid-like tumours was developed in mice through stable transfection of BPV-1 E5 and E6 in a murine fibroblast tumour cell line (K-BALB). Like equine sarcoids, these murine tumour cells (BPV-KB) were of fibroblast origin, were tumorigenic and expressed BPV-1 proteins. As an initial investigation of the preclinical potential of this tumour model for equine sarcoids prophylactics, mice were immunized with BPV-1 E5E6 Venezuelan equine encephalitis virus replicon particles, prior to BPV-KB challenge, which resulted in an increased tumour-free period compared with controls, indicating that the BPV-KB murine model may be a valuable preclinical alternative to equine clinical trials. PMID:26044793

A novel murine model for evaluating bovine papillomavirus prophylactics/therapeutics for equine sarcoid-like tumours.

PubMed

Bogaert, Lies; Woodham, Andrew W; Da Silva, Diane M; Martens, Ann; Meyer, Evelyne; Kast, W Martin

2015-09-01

Equine sarcoids are highly recurrent bovine papillomavirus (BPV)-induced fibroblastic neoplasms that are the most common skin tumours in horses. In order to facilitate the study of potential equine sarcoid prophylactics or therapeutics, which can be a slow and costly process in equines, a murine model for BPV-1 protein-expressing equine sarcoid-like tumours was developed in mice through stable transfection of BPV-1 E5 and E6 in a murine fibroblast tumour cell line (K-BALB). Like equine sarcoids, these murine tumour cells (BPV-KB) were of fibroblast origin, were tumorigenic and expressed BPV-1 proteins. As an initial investigation of the preclinical potential of this tumour model for equine sarcoids prophylactics, mice were immunized with BPV-1 E5E6 Venezuelan equine encephalitis virus replicon particles, prior to BPV-KB challenge, which resulted in an increased tumour-free period compared with controls, indicating that the BPV-KB murine model may be a valuable preclinical alternative to equine clinical trials.

Detection of adulterated murine components in meat products by TaqMan© real-time PCR.

PubMed

Fang, Xin; Zhang, Chi

2016-02-01

Using murine meat to substitute mutton has been identified as a new type of meat fraud in China, yet no detection method for murine species has been reported. Here, three kinds of rodent were used as target species to establish a murine-specific real-time PCR method of detection. The mitochondrial cytochrome b gene (cytb) of each target was sequenced and a TaqMan probe was designed based on the cytb. Simultaneously, an internal positive control (IPC) plasmid along with its respective probe were designed to monitor the PCR reaction. As a result, the duplex real-time PCR system was verified to be specific. The limit of detection (LOD) was lower than 1 pg of DNA per reaction and 0.1% murine contamination in meat mixtures. Standard curves were generated for a quantitative analysis. Thus, this study provided a new tool to control the quality of meat products for official and third-party laboratories. Copyright © 2015. Published by Elsevier Ltd.

Endogenous Auxin and Ethylene in Pellia (Bryophyta) 1

PubMed Central

Thomas, Robert J.; Harrison, Marcia A.; Taylor, Jane; Kaufman, Peter B.

1983-01-01

The occurrence of endogenous indole-3-acetic acid and ethylene in bryophyte tissue was tentatively demonstrated using gas chromatography, high performance liquid chromatography, and double-standard isotope dilution techniques. Rapidly elongating stalks (or setae) of Pellia epiphylla (L.) Corda sporophytes contain approximately 2.5 to 2.9 micrograms per gram fresh weight of putative free IAA. Ethylene released by setae increases during growth from 0.027 to 0.035 nanoliter per seta per hour. Application of 5 microliters per liter ethylene inhibits auxin-stimulated elongation growth of this tissue, a result which suggests that both endogenously produced compounds act in tandem as natural growth modulators. Images Fig. 1 PMID:16663227

Osmotic characteristics and fertility of murine spermatozoa collected in different solutions.

PubMed

Si, Wei; Men, Hongsheng; Benson, James D; Critser, John K

2009-02-01

Osmotic stress is an important factor that can result in cell damage during cryopreservation. Before ejaculation or collection for cryopreservation, murine spermatozoa are stored in epididymal fluid, a physiologically hyperosmotic environment (approximately 415 mmol/kg). The objectives of this study were to determine the osmotic tolerance limits of sperm motion parameters of ICR and C57BL/6 mouse spermatozoa collected in isosmotic (290 mmol/kg) and hyperosmotic (415 mmol/kg) media, and the effect of the osmolality of sperm collection media on sperm fertility after cryopreservation. Our results indicate that murine spermatozoa collected in media with different osmolalities (290 and 415 mmol/kg Dulbecco's phosphate buffered saline (DPBS)) appeared to have different osmotic tolerances for the maintenance of sperm motility and other motion parameters in both mouse strains. The hypo- and hyperosmotic treatments decreased motility and affected other motion parameters of spermatozoa collected in 290 mmol/kg DPBS. The extent of the change of motion parameters after treatments corresponded with the levels of osmotic stress. However, for spermatozoa collected in 415 mmol/kg DPBS, exposure to 290 mmol/kg DPBS tended to increase sperm motility and the quality of their motion parameters. The osmolality of sperm collection medium can affect murine sperm fertility. Spermatozoa collected in 415 mmol/kg medium showed higher fertility compared with spermatozoa collected in 290 mmol/kg as assessed by IVF. Results characterizing murine sperm osmotic tolerance collected in media with different osmolalities from different strains and the effect of collection media osmolality on sperm fertility after cryopreservation will be useful in designing cryopreservation protocols.

Influence of endogenous pyrogen on the cerebral prostaglandin-synthetase system.

PubMed

Ziel, R; Krupp, P

1976-11-15

The biotransformation of arachidonic acid to prostaglandins in vitro is specifically augmented by endogenous pyrogen to a degree depending on the concentration applied, providing that the microsomal fraction of the cerebral cortex is used as prostaglandin-synthetase system. This effect is inhibited by non-steroidal anti-inflammatory agents. These findings are compatible with the hypothesis that prostaglandins might act as mediators of the febrile reaction induced by endogenous pyrogen.

Endogenous Magnetic Reconnection in Solar Coronal Loops

NASA Astrophysics Data System (ADS)

Asgari-Targhi, M.; Coppi, B.; Basu, B.; Fletcher, A.; Golub, L.

2017-12-01

We propose that a magneto-thermal reconnection process occurring in coronal loops be the source of the heating of the Solar Corona [1]. In the adopted model, magnetic reconnection is associated with electron temperature gradients, anisotropic electron temperature fluctuations and plasma current density gradients [2]. The input parameters for our theoretical model are derived from the most recent observations of the Solar Corona. In addition, the relevant (endogenous) collective modes can produce high energy particle populations. An endogenous reconnection process is defined as being driven by factors internal to the region where reconnection takes place. *Sponsored in part by the U.S. D.O.E. and the Kavli Foundation* [1] Beafume, P., Coppi, B. and Golub, L., (1992) Ap. J. 393, 396. [2] Coppi, B. and Basu, B. (2017) MIT-LNS Report HEP 17/01.

The Cannabinoid Acids, Analogs and Endogenous Counterparts

PubMed Central

Burstein, Sumner H.

2015-01-01

The cannabinoid acids are a structurally heterogeneous group of compounds some of which are endogenous molecules and others that are metabolites of phytocannabinoids. The prototypic endogenous substance is N-arachidonoyl glycine (NAgly) that is closely related in structure to the cannabinoid agonist anandamide. The most studied phytocannabinoid is Δ9–THC-11-oic acid, the principal metabolite of Δ9–THC. Both types of acids have in common several biological actions such as low affinity for CB1, anti-inflammatory activity and analgesic properties. This suggests that there may be similarities in their mechanism of action, a point that is discussed in this review. Also presented are reports on analogs of the acids that provide opportunities for the development of novel therapeutic agents, such as ajulemic acid. PMID:24731541

Protective effects of astaxanthin from Paracoccus carotinifaciens on murine gastric ulcer models.

PubMed

Murata, Kenta; Oyagi, Atsushi; Takahira, Dai; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Ishibashi, Takashi; Hara, Hideaki

2012-08-01

The purpose of this study was to investigate the effect of astaxanthin extracted from Paracoccus carotinifaciens on gastric mucosal damage in murine gastric ulcer models. Mice were pretreated with astaxanthin for 1 h before ulcer induction. Gastric ulcers were induced in mice by oral administration of hydrochloride (HCl)/ethanol or acidified aspirin. The effect of astaxanthin on lipid peroxidation in murine stomach homogenates was also evaluated by measuring the level of thiobarbituric acid reactive substance (TBARS). The free radical scavenging activities of astaxanthin were also measured by electron spin resonance (ESR) measurements. Astaxanthin significantly decreased the extent of HCl/ethanol- and acidified aspirin-induced gastric ulcers. Astaxanthin also decreased the level of TBARS. The ESR measurement showed that astaxanthin had radical scavenging activities against the 1,1-diphenyl-2-picrylhydrazyl radical and the superoxide anion radical. These results suggest that astaxanthin has antioxidant properties and exerts a protective effect against ulcer formation in murine models. Copyright © 2011 John Wiley & Sons, Ltd.

Comparison of endogenous and radiolabeled bile acid excretion in patients with idiopathic chronic diarrhea

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

Schiller, L.R.; Bilhartz, L.E.; Santa Ana, C.A.

Fecal recovery of radioactivity after ingestion of a bolus of radiolabeled bile acid is abnormally high in most patients with idiopathic chronic diarrhea. To evaluate the significance of this malabsorption, concurrent fecal excretion of both exogenous radiolabeled bile acid and endogenous (unlabeled) bile acid were measured in patients with idiopathic chronic diarrhea. Subjects received a 2.5-microCi oral dose of taurocholic acid labeled with 14C in the 24th position of the steroid moiety. Endogenous bile acid excretion was measured by a hydroxysteroid dehydrogenase assay on a concurrent 72-h stool collection. Both radiolabeled and endogenous bile acid excretion were abnormally high inmore » most patients with chronic diarrhea compared with normal subjects, even when equivoluminous diarrhea was induced in normal subjects by ingestion of osmotically active solutions. The correlation between radiolabeled and endogenous bile acid excretion was good. However, neither radiolabeled nor endogenous bile acid excretion was as abnormal as is typically seen in patients with ileal resection, and none of these diarrhea patients responded to treatment with cholestyramine with stool weights less than 200 g. These results suggest (a) that this radiolabeled bile acid excretion test accurately reflects excess endogenous bile acid excretion; (b) that excess endogenous bile acid excretion is not caused by diarrhea per se; (c) that spontaneously occurring idiopathic chronic diarrhea is often associated with increased endogenous bile acid excretion; and (d) that bile acid malabsorption is not likely to be the primary cause of diarrhea in most of these patients.« less

Generation of murine tumor cell lines deficient in MHC molecule surface expression using the CRISPR/Cas9 system.

PubMed

Das, Krishna; Eisel, David; Lenkl, Clarissa; Goyal, Ashish; Diederichs, Sven; Dickes, Elke; Osen, Wolfram; Eichmüller, Stefan B

2017-01-01

In this study, the CRISPR/Cas9 technology was used to establish murine tumor cell lines, devoid of MHC I or MHC II surface expression, respectively. The melanoma cell line B16F10 and the murine breast cancer cell line EO-771, the latter stably expressing the tumor antigen NY-BR-1 (EO-NY), were transfected with an expression plasmid encoding a β2m-specific single guide (sg)RNA and Cas9. The resulting MHC I negative cells were sorted by flow cytometry to obtain single cell clones, and loss of susceptibility of peptide pulsed MHC I negative clones to peptide-specific CTL recognition was determined by IFNγ ELISpot assay. The β2m knockout (KO) clones did not give rise to tumors in syngeneic mice (C57BL/6N), unless NK cells were depleted, suggesting that outgrowth of the β2m KO cell lines was controlled by NK cells. Using sgRNAs targeting the β-chain encoding locus of the IAb molecule we also generated several B16F10 MHC II KO clones. Peptide loaded B16F10 MHC II KO cells were insusceptible to recognition by OT-II cells and tumor growth was unaltered compared to parental B16F10 cells. Thus, in our hands the CRISPR/Cas9 system has proven to be an efficient straight forward strategy for the generation of MHC knockout cell lines. Such cell lines could serve as parental cells for co-transfection of compatible HLA alleles together with human tumor antigens of interest, thereby facilitating the generation of HLA matched transplantable tumor models, e.g. in HLAtg mouse strains of the newer generation, lacking cell surface expression of endogenous H2 molecules. In addition, our tumor cell lines established might offer a useful tool to investigate tumor reactive T cell responses that function independently from MHC molecule surface expression by the tumor.

Endogenous lung surfactant inspired pH responsive nanovesicle aerosols: Pulmonary compatible and site-specific drug delivery in lung metastases

NASA Astrophysics Data System (ADS)

Joshi, Nitin; Shirsath, Nitesh; Singh, Ankur; Joshi, Kalpana S.; Banerjee, Rinti

2014-11-01

Concerns related to pulmonary toxicity and non-specificity of nanoparticles have limited their clinical applications for aerosol delivery of chemotherapeutics in lung cancer. We hypothesized that pulmonary surfactant mimetic nanoparticles that offer pH responsive release specifically in tumor may be a possible solution to overcome these issues. We therefore developed lung surfactant mimetic and pH responsive lipid nanovesicles for aerosol delivery of paclitaxel in metastatic lung cancer. 100-200 nm sized nanovesicles showed improved fusogenicity and cytosolic drug release, specifically with cancer cells, thereby resulting in improved cytotoxicity of paclitaxel in B16F10 murine melanoma cells and cytocompatibility with normal lung fibroblasts (MRC 5). The nanovesicles showed airway patency similar to that of endogenous pulmonary surfactant and did not elicit inflammatory response in alveolar macrophages. Their aerosol administration while significantly improving the biodistribution of paclitaxel in comparison to Taxol (i.v.), also showed significantly higher metastastes inhibition (~75%) in comparison to that of i.v. Taxol and i.v. Abraxane. No signs of interstitial pulmonary fiborisis, chronic inflammation and any other pulmonary toxicity were observed with nanovesicle formulation. Overall, these nanovesicles may be a potential platform to efficiently deliver hydrophobic drugs as aerosol in metastatic lung cancer and other lung diseases, without causing pulmonary toxicity.

Fungal mycelia show lag time before re-growth on endogenous carbon.

PubMed

Pollack, Judith K; Li, Zheng Jian; Marten, Mark R

2008-06-15

Nutrient starvation is a common occurrence for filamentous fungi. To better understand the effects of starvation, we used a parallel plate flow chamber to study individual fungal mycelia when subjected to a step change in glucose concentration. We report the presence of a finite "lag time" in starved mycelia during which they ceased to grow/extend while switching from growth on exogenous carbon to re-growth on endogenous carbon. This lag time precedes other morphological or physiological changes such as change in growth rate (50-70% reduction), vacuolation (up to 16%), and decreased hyphal diameter (almost 50% reduction). Data suggests that during lag time, vacuolar degradation produces sufficient endogenous carbon to support survival and restart hyphal extension. Lag time is inversely related to the size of the mycelium at the time of starvation, which suggests a critical flow of endogenous carbon to the apical tip. We present a mathematical model consistent with our experimental observations that relate lag time, area, and flow of endogenous carbon. (c) 2008 Wiley Periodicals, Inc.

Endogenous Positive Allosteric Modulation of GABAA Receptors by Diazepam binding inhibitor

PubMed Central

Christian, Catherine A.; Herbert, Anne G.; Holt, Rebecca L.; Peng, Kathy; Sherwood, Kyla D.; Pangratz-Fuehrer, Susanne; Rudolph, Uwe; Huguenard, John R.

2014-01-01

Summary Benzodiazepines (BZs) allosterically modulate γ-aminobutyric acid type-A receptors (GABAARs) to increase inhibitory synaptic strength. Diazepam binding inhibitor (DBI) protein is a BZ site ligand expressed endogenously in the brain, but functional evidence for BZ-mimicking positive modulatory actions has been elusive. We demonstrate an endogenous potentiation of GABAergic synaptic transmission and responses to GABA uncaging in the thalamic reticular nucleus (nRT) that is absent in both nm1054 mice, in which the Dbi gene is deleted, and mice in which BZ binding to α3 subunit-containing GABAARs is disrupted. Viral transduction of DBI into nRT is sufficient to rescue the endogenous potentiation of GABAergic transmission in nm1054 mice. Both mutations enhance thalamocortical spike-and-wave discharges characteristic of absence epilepsy. Together these results indicate that DBI mediates endogenous nucleus-specific BZ-mimicking (“endozepine”) roles to modulate nRT function and suppress thalamocortical oscillations. Enhanced DBI signaling might serve as a novel therapy for epilepsy and other neurological disorders. PMID:23727119

Lipopolysaccharide-induced murine embryonic resorption involves changes in endocannabinoid profiling and alters progesterone secretion and inflammatory response by a CB1-mediated fashion.

PubMed

Wolfson, Manuel L; Correa, Fernando; Leishman, Emma; Vercelli, Claudia; Cymeryng, Cora; Blanco, Julieta; Bradshaw, Heather B; Franchi, Ana María

2015-08-15

Genital tract infections are a common complication of human pregnancy that can result in miscarriage. We have previously shown that a lipopolysaccharide (LPS) induces embryonic resorption in a murine model of inflammatory miscarriage. This is accompanied by a dramatic decrease in systemic progesterone levels associated with a robust pro-inflammatory response that results in embryo resorption. Here, we tested the hypothesis that the endogenous cannabinoid system (eCS), through cannabinoid receptor 1 (CB1), plays a role in regulating progesterone levels and, therefore, the pro-inflammatory response. We show that LPS treatment in pregnant mice causes significant changes in the eCS ligands, which are reversed by progesterone treatment. We further show the CB1-KO mice maintain higher plasma progesterone levels after LPS treatment, which is associated with a feebler uterine inflammatory response and a significant drop in embryo resorption. These data suggest that manipulation of CB1 receptors and/or ligands is a potential therapeutic avenue to decrease infection-induced miscarriage. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Magnetic resonance imaging and spectroscopy of the murine cardiovascular system

PubMed Central

Akki, Ashwin; Gupta, Ashish

2013-01-01

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease. PMID:23292717

[Exploration of the Essence of "Endogenous Turbidity" in Chinese Medicine].

PubMed

Fan, Xin-rong; Tang, Nong; Ji, Yun-xi; Zhang, Yao-zhong; Jiang, Li; Huang, Gui-hua; Xie, Sheng; Li, Liu-mei; Song, Chun-hui; Ling, Jiang-hong

2015-08-01

The essence of endogenous turbidity in Chinese medicine (CM) is different from cream, fat, phlegm, retention, damp, toxicity, and stasis. Along with the development of modern scientific technologies and biology, researches on the essence of endogenous turbidity should keep pace with the time. Its material bases should be defined and new connotation endowed at the microscopic level. The essence of turbidity lies in abnormal functions of zang-fu organs. Sugar, fat, protein, and other nutrient substances cannot be properly decomposed, but into semi-finished products or intermediate metabolites. They are inactive and cannot participate in normal material syntheses and decomposition. They cannot be transformed to energy metabolism, but also cannot be synthesized as executive functioning of active proteins. If they cannot be degraded by autophagy-lysosome or ubiquitin-prosome into glucose, fatty acids, amino acids, and other basic nutrients to be used again, they will accumulate inside the human body and become endogenous turbidity. Therefore, endogenous turbidity is different from final metabolites such as urea, carbon dioxide, etc., which can transform vital qi. How to improve the function of zang-fu organs, enhance its degradation by autophagy-lysosome or ubiquitin-prosome is of great significance in normal operating of zang-fu organs and preventing the emergence and progress of related diseases.

First steps to define murine amniotic fluid stem cell microenvironment.

PubMed

Bertin, E; Piccoli, M; Franzin, C; Spiro, G; Donà, S; Dedja, A; Schiavi, F; Taschin, E; Bonaldo, P; Braghetta, P; De Coppi, P; Pozzobon, M

2016-11-15

Stem cell niche refers to the microenvironment where stem cells reside in living organisms. Several elements define the niche and regulate stem cell characteristics, such as stromal support cells, gap junctions, soluble factors, extracellular matrix proteins, blood vessels and neural inputs. In the last years, different studies demonstrated the presence of cKit + cells in human and murine amniotic fluid, which have been defined as amniotic fluid stem (AFS) cells. Firstly, we characterized the murine cKit + cells present both in the amniotic fluid and in the amnion. Secondly, to analyze the AFS cell microenvironment, we injected murine YFP + embryonic stem cells (ESC) into the amniotic fluid of E13.5 wild type embryos. Four days after transplantation we found that YFP + sorted cells maintained the expression of pluripotency markers and that ESC adherent to the amnion were more similar to original ESC in respect to those isolated from the amniotic fluid. Moreover, cytokines evaluation and oxygen concentration analysis revealed in this microenvironment the presence of factors that are considered key regulators in stem cell niches. This is the first indication that AFS cells reside in a microenvironment that possess specific characteristics able to maintain stemness of resident and exogenous stem cells.

Endogenously and exogenously driven selective sustained attention: Contributions to learning in kindergarten children.

PubMed

Erickson, Lucy C; Thiessen, Erik D; Godwin, Karrie E; Dickerson, John P; Fisher, Anna V

2015-10-01

Selective sustained attention is vital for higher order cognition. Although endogenous and exogenous factors influence selective sustained attention, assessment of the degree to which these factors influence performance and learning is often challenging. We report findings from the Track-It task, a paradigm that aims to assess the contribution of endogenous and exogenous factors to selective sustained attention within the same task. Behavioral accuracy and eye-tracking data on the Track-It task were correlated with performance on an explicit learning task. Behavioral accuracy and fixations to distractors during the Track-It task did not predict learning when exogenous factors supported selective sustained attention. In contrast, when endogenous factors supported selective sustained attention, fixations to distractors were negatively correlated with learning. Similarly, when endogenous factors supported selective sustained attention, higher behavioral accuracy was correlated with greater learning. These findings suggest that endogenously and exogenously driven selective sustained attention, as measured through different conditions of the Track-It task, may support different kinds of learning. Copyright © 2015 Elsevier Inc. All rights reserved.

1.8 Å structure of murine GITR ligand dimer expressed in Drosophila melanogaster S2 cells

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

Chattopadhyay, Kausik; Ramagopal, Udupi A.; Nathenson, Stanley G., E-mail: nathenso@aecom.yu.edu

2009-05-01

1.8 Å X-ray crystal structure of mouse GITRL expressed in D. melanogaster S2 cells shows an identical ‘strand-exchanged’ dimeric assembly similar to that observed previously for the E. coli-expressed protein. Glucocorticoid-induced TNF receptor ligand (GITRL), a prominent member of the TNF superfamily, activates its receptor on both effector and regulatory T cells to generate critical costimulatory signals that have been implicated in a wide range of T-cell immune functions. The crystal structures of murine and human orthologs of GITRL recombinantly expressed in Escherichia coli have previously been determined. In contrast to all classical TNF structures, including the human GITRL structure,more » murine GITRL demonstrated a unique ‘strand-exchanged’ dimeric organization. Such a novel assembly behavior indicated a dramatic impact on receptor activation as well as on the signaling mechanism associated with the murine GITRL costimulatory system. In this present work, the 1.8 Å resolution crystal structure of murine GITRL expressed in Drosophila melanogaster S2 cells is reported. The eukaryotic protein-expression system allows transport of the recombinant protein into the extracellular culture medium, thus maximizing the possibility of obtaining correctly folded material devoid of any folding/assembly artifacts that are often suspected with E. coli-expressed proteins. The S2 cell-expressed murine GITRL adopts an identical ‘strand-exchanged’ dimeric structure to that observed for the E. coli-expressed protein, thus conclusively demonstrating the novel quaternary structure assembly behavior of murine GITRL.« less

Clinical Efficacy Associated with Enhanced Antioxidant Enzyme Activities of Silver Nanoparticles Biosynthesized Using Moringa oleifera Leaf Extract, Against Cutaneous Leishmaniasis in a Murine Model of Leishmania major.

PubMed

El-Khadragy, Manal; Alolayan, Ebtesam M; Metwally, Dina M; El-Din, Mohamed F Serag; Alobud, Sara S; Alsultan, Nour I; Alsaif, Sarah S; Awad, Manal A; Abdel Moneim, Ahmed E

2018-05-22

Leishmaniasis is one of the most significant vector-borne syndromes of individuals. This parasitic infection can be affected by many species of Leishmania, most of which are zoonotic. Natural products have made and are continuing to make important contributions to the search for new antileishmanial agents. The use of plants in the production assembly of silver nanoparticles has drawn attention because of its rapid, eco-friendly, non-pathogenic, economical protocol and provides a single step technique for the biosynthetic process. Hence, we aimed to biosynthesize silver nanoparticles (Ag-NPs) using Moringa oleifera leaf extract and investigated the antileishmanial activity of these nanoparticles in a murine model of Leishmania major infection. A total of 50 mice were used and divided into five groups-healthy control, infected, infected mice treated with pentostam, infected mice treated with Ag-NPs and infected mice pretreated with Ag-NPs. In the present study, the leaf extract of the plant species Moringa oleifera was found to be a good source for the synthesis of silver nanoparticles, their formation being confirmed by color change and stability in solution. In the present murine model of Leishmania major infection, we found that oral treatment with silver nanoparticles biosynthesized using Moringa oleifera extract resulted in a significant reduction in the average size of leishmaniasis cutaneous lesions compared with untreated mice. Furthermore, the clinical efficacy of Moringa oleifera extract was associated with enhanced antioxidant enzyme activities. In conclusion, treatment with silver nanoparticles biosynthesized using Moringa oleifera extract has higher and faster clinical efficacy than standard pentavalent antimonial treatment, probably by boosting the endogenous antioxidant activity.

Murine recombinant angiotensin-converting enzyme 2 attenuates kidney injury in experimental Alport syndrome.

PubMed

Bae, Eun Hui; Fang, Fei; Williams, Vanessa R; Konvalinka, Ana; Zhou, Xiaohua; Patel, Vaibhav B; Song, Xuewen; John, Rohan; Oudit, Gavin Y; Pei, York; Scholey, James W

2017-06-01

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase in the renin-angiotensin system that catalyzes the breakdown of angiotensin II to angiotensin 1-7. We have reported that ACE2 expression in the kidney is reduced in experimental Alport syndrome but the impact of this finding on disease progression has not been studied. Accordingly, we evaluated effects of murine recombinant ACE2 treatment in Col4a3 knockout mice, a model of Alport syndrome characterized by proteinuria and progressive renal injury. Murine recombinant ACE2 (0.5 mg/kg/day) was administered from four to seven weeks of age via osmotic mini-pump. Pathological changes were attenuated by murine recombinant ACE2 treatment which ameliorated kidney fibrosis as shown by decreased expression of COL1α1 mRNA, less accumulation of extracellular matrix proteins, and inhibition of transforming growth factor-β signaling. Further, increases in proinflammatory cytokine expression, macrophage infiltration, inflammatory signaling pathway activation, and heme oxygenase-1 levels in Col4a3 knockout mice were also reduced by murine recombinant ACE2 treatment. Lastly, murine recombinant ACE2 influenced the turnover of renal ACE2, as it suppressed the expression of tumor necrosis factor-α converting enzyme, a negative regulator of ACE2. Thus, treatment with exogenous ACE2 alters angiotensin peptide metabolism in the kidneys of Col4a3 knockout mice and attenuates the progression of Alport syndrome nephropathy. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Glutathione S-transferase pi isoform (GSTP1) expression in murine retina increases with developmental maturity.

PubMed

Lee, Wen-Hsiang; Joshi, Pratibha; Wen, Rong

2014-01-01

Glutathione S-transferase pi isoform (GSTP1) is an intracellular detoxification enzyme that catalyzes reduction of chemically reactive electrophiles and is a zeaxanthin-binding protein in the human macula. We have previously demonstrated that GSTP1 levels are decreased in human age-related macular degeneration (AMD) retina compared to normal controls (Joshi et al., Invest Ophthalmol Vis Sci, e-abstract, 2009). We also showed that GSTP1 levels parallel survival of human retinal pigment epithelial (RPE) cells exposed to ultraviolet (UV) light, and GSTP1 over-expression protects them against UV light damage (Joshi et al., Invest Ophthalmol Vis Sci, e-abstract, 2010). In the present work, we determined the developmental time course of GSTP1 expression in murine retina and in response to light challenge. Eyes from BALB/c mice at postnatal day 20, 1 month, and 2 months of age were prepared for retinal protein extraction and cryo sectioning, and GSTP1 levels in the retina were analyzed by Western blot and immunohistochemistry (IHC). Another group of BALB/c mice with the same age ranges was exposed to 1000 lx of white fluorescent light for 24 h, and their retinas were analyzed for GSTP1 expression by Western blot and IHC in a similar manner. GSTP1 levels in the murine retina increased in ascending order from postnatal day 20, 1 month, and 2 months of age. Moreover, GSTP1 expression in murine retina at postnatal day 20, 1 month, and 2 months of age increased in response to brief light exposure compared to age-matched controls under normal condition. GSTP1 expression in retina increases with developmental age in mice and accompanies murine retinal maturation. Brief exposure to light induces GSTP1 expression in the murine retina across various developmental ages. GSTP1 induction may be a protective response to light-induced oxidative damage in the murine retina.

Glutathione S-Transferase Pi Isoform (GSTP1) Expression in Murine Retina Increases with Developmental Maturity

PubMed Central

Lee, Wen-Hsiang; Joshi, Pratibha; Wen, Rong

2014-01-01

Background and Aims Glutathione S-transferase pi isoform (GSTP1) is an intracellular detoxification enzyme that catalyzes reduction of chemically reactive electrophiles and is a zeaxanthin-binding protein in the human macula. We have previously demonstrated that GSTP1 levels are decreased in human age-related macular degeneration (AMD) retina compared to normal controls [1]. We also showed that GSTP1 levels parallel survival of human retinal pigment epithelial (RPE) cells exposed to UV light, and GSTP1 over-expression protects them against UV light damage [2]. In the present work, we determined the developmental time course of GSTP1 expression in murine retina and in response to light challenge. Methods Eyes from BALB/c mice at post-natal day 20, 1 month, and 2 months of age were prepared for retinal protein extraction and cryo sectioning, and GSTP1 levels in the retina were analyzed by Western blot and immunohistochemistry (IHC). Another group of BALB/c mice with the same age ranges was exposed to 1000 lux of white fluorescent light for 24 hours, and their retinas were analyzed for GSTP1 expression by Western blot and IHC in a similar manner. Results GSTP1 levels in the murine retina increased in ascending order from post-natal day 20, 1 month, and 2 months of age. Moreover, GSTP1 expression in murine retina at post-natal day 20, 1 month, and 2 months of age increased in response to brief light exposure compared to age-matched controls under normal condition. Conclusions GSTP1 expression in retina increases with developmental age in mice and accompanies murine retinal maturation. Brief exposure to light induces GSTP1 expression in the murine retina across various developmental ages. GSTP1 induction may be a protective response to light-induced oxidative damage in the murine retina. PMID:24664677

Endogenous technological and demographic change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, Saket; Ertsen, Maurits; Sivapalan, Murugesu

2014-05-01

The ancient civilization in the Indus Valley civilization dispersed under extreme dry conditions; there are indications that the same holds for many other ancient societies. Even contemporary societies, such as the one in Murrumbidgee river basin in Australia, have started to witness a decline in overall population under increasing water scarcity. Hydroclimatic change may not be the sole predictor of the fate of contemporary societies in water scarce regions and many critics of such (perceived) hydroclimatic determinism have suggested that technological change may ameliorate the effects of increasing water scarcity and as such counter the effects of hydroclimatic changes. To study the role of technological change on the dynamics of coupled human-water systems, we develop a simple overlapping-generations model of endogenous technological and demographic change. We model technological change as an endogenous process that depends on factors such as the investments that are (endogenously) made in a society, the (endogenous) diversification of a society into skilled and unskilled workers, a society's patience in terms of its present consumption vs. future consumption, production technology and the (endogenous) interaction of all of these factors. In the model the population growth rate is programmed to decline once consumption per capita crosses a "survival" threshold. This means we do not treat technology as an exogenous random sequence of events, but instead assume that it results (endogenously) from societal actions. The model demonstrates that technological change may indeed ameliorate the effects of increasing water scarcity but typically it does so only to a certain extent. It is possible that technological change may allow a society to escape the effect of increasing water scarcity, leading to a (super)-exponential rise in technology and population. However, such cases require the rate of success of investment in technological advancement to be high. In other

Endogenous technological and population change under increasing water scarcity

NASA Astrophysics Data System (ADS)

Pande, S.; Ertsen, M.; Sivapalan, M.

2013-11-01

The ancient civilization in the Indus Valley civilization dispersed under extreme dry conditions; there are indications that the same holds for many other ancient societies. Even contemporary societies, such as the one in Murrumbidgee river basin in Australia, have started to witness a decline in overall population under increasing water scarcity. Hydroclimatic change may not be the sole predictor of the fate of contemporary societies in water scarce regions and many critics of such (perceived) hydroclimatic determinism have suggested that technological change may ameliorate the effects of increasing water scarcity and as such counter the effects of hydroclimatic changes. To study the role of technological change on the dynamics of coupled human-water systems, we develop a simple overlapping-generations model of endogenous technological and demographic change. We model technological change as an endogenous process that depends on factors such as the investments that are (endogenously) made in a society, the (endogenous) diversification of a society into skilled and unskilled workers, a society's patience in terms of its present consumption vs. future consumption, production technology and the (endogenous) interaction of all of these factors. In the model the population growth rate is programmed to decline once consumption per capita crosses a "survival" threshold. This means we do not treat technology as an exogenous random sequence of events, but instead assume that it results (endogenously) from societal actions. The model demonstrates that technological change may indeed ameliorate the effects of increasing water scarcity but typically it does so only to a certain extent. It is possible that technological change may allow a society to escape the effect of increasing water scarcity, leading to a (super)-exponential rise in technology and population. However, such cases require the rate of success of investment in technological advancement to be high. In other

Correction of murine mucopolysaccharidosis VII by a human. beta. -glucuronidase transgene

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