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Sample records for mediated mitochondrial protection

  1. CDK4-mediated MnSOD activation and mitochondrial homeostasis in radioadaptive protection

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    Jin, Cuihong; Qin, Lili; Shi, Yan; Candas, Demet; Fan, Ming; Lu, Chung-Ling; Vaughan, Andrew T. M.; Shen, Rulong; Wu, Larry S.; Liu, Rui; Li, Robert F.; Murley, Jeffrey S.; Gayle, Woloschak; Grdina, David J.; Li, Jian Jian

    2015-01-01

    Mammalian cells are able to sense environmental oxidative and genotoxic conditions such as the environmental low dose ionizing radiation (LDIR) present naturally on earth surface. The stressed cells then can induce a so-called radioadaptive response with an enhanced cellular homeostasis and repair capacity against subsequent similar genotoxic conditions such as a high dose radiation. MnSOD, a primary mitochondrial antioxidant in mammals, has long been known to play a crucial role in the radioadaptive protection through detoxifying O2·- generated by mitochondrial oxidative phosphorylation. Contrasted to the well-studied mechanisms of SOD2 gene regulation, the mechanisms underlying post-translational regulation of MnSOD for radioprotection remain to be defined. Herein, we demonstrate that Cyclin D1-cyclin-dependent kinase 4 (CDK4) serves as the messenger to deliver the stress signal to mitochondria to boost mitochondrial homeostasis in human skin keratinocytes under LDIR adaptive radioprotection. Cyclin D1/CDK4 is found to relocate to mitochondria at the same time as MnSOD enzymatic activation peaks without significant changes of total MnSOD protein level. The mitochondrial-localized CDK4 directly phosphorylates MnSOD at Serine 106 (S106), causing enhanced MnSOD enzymatic activity and mitochondrial respiration. Expression of mitochondria-targeted dominant negative CDK4 or the MnSOD-S106A mutant reverses LDIR-induced mitochondrial enhancement and adaptive protection. The CDK4-mediated MnSOD activation and mitochondrial metabolism boost are also detected in skin tissues of mice receiving in vivo whole body LDIR. These results demonstrate a unique CDK4-mediated mitochondrial communication that allows cells to sense environmental genotoxic stress and boost mitochondrial homeostasis via enhancing phosphorylation and activation of MnSOD. PMID:25578653

  2. Melatonin Mediates Protective Effects against Kainic Acid-Induced Neuronal Death through Safeguarding ER Stress and Mitochondrial Disturbance

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    Xue, Feixiao; Shi, Cai; Chen, Qingjie; Hang, Weijian; Xia, Liangtao; Wu, Yue; Tao, Sophia Z.; Zhou, Jie; Shi, Anbing; Chen, Juan

    2017-01-01

    Kainic acid (KA)-induced neuronal death is linked to mitochondrial dysfunction and ER stress. Melatonin is known to protect hippocampal neurons from KA-induced apoptosis, but the exact mechanisms underlying melatonin protective effects against neuronal mitochondria disorder and ER stress remain uncertain. In this study, we investigated the sheltering roles of melatonin during KA-induced apoptosis by focusing on mitochondrial dysfunction and ER stress mediated signal pathways. KA causes mitochondrial dynamic disorder and dysfunction through calpain activation, leading to neuronal apoptosis. Ca2+ chelator BAPTA-AM and calpain inhibitor calpeptin can significantly restore mitochondrial morphology and function. ER stress can also be induced by KA treatment. ER stress inhibitor 4-phenylbutyric acid (PBA) attenuates ER stress-mediated apoptosis and mitochondrial disorder. It is worth noting that calpain activation was also inhibited under PBA administration. Thus, we concluded that melatonin effectively inhibits KA-induced calpain upregulation/activation and mitochondrial deterioration by alleviating Ca2+ overload and ER stress. PMID:28293167

  3. C-Phycocyanin Confers Protection against Oxalate-Mediated Oxidative Stress and Mitochondrial Dysfunctions in MDCK Cells

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    Farooq, Shukkur M.; Boppana, Nithin B.; Asokan, Devarajan; Sekaran, Shamala D.; Shankar, Esaki M.; Li, Chunying; Gopal, Kaliappan; Bakar, Sazaly A.; Karthik, Harve S.; Ebrahim, Abdul S.

    2014-01-01

    Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis. PMID:24691130

  4. Mitochondrial protection by resveratrol.

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    Ungvari, Zoltan; Sonntag, William E; de Cabo, Rafael; Baur, Joseph A; Csiszar, Anna

    2011-07-01

    Mitochondrial dysfunction and oxidative stress are thought to play important roles in mammalian aging. Resveratrol is a plant-derived polyphenol that exerts diverse antiaging activities, mimicking some of the molecular and functional effects of dietary restriction. This review focuses on the molecular mechanisms underlying the mitochondrial protective effects of resveratrol, which could be exploited for the prevention or amelioration of age-related diseases in the elderly.

  5. Quercetin Induces Mitochondrial Mediated Apoptosis and Protective Autophagy in Human Glioblastoma U373MG Cells

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    Hyeonji Kim

    2013-01-01

    Full Text Available Quercetin is a dietary flavonoid with known antitumor effects against several types of cancers by promoting apoptotic cell death and inducing cell cycle arrest. However, U373MG malignant glioma cells expressing mutant p53 are resistant to a 24 h quercetin treatment. In this study, the anticancer effect of quercetin was reevaluated in U373MG cells, and quercetin was found to be significantly effective in inhibiting proliferation of U373MG cells in a concentration-dependent manner after 48 and 72 h of incubation. Quercetin induced U373MG cell death through apoptosis, as evidenced by the increased number of cells in the sub-G1 phase, the appearance of fragmented nuclei, decreased mitochondrial membrane potential, proteolytic activation of caspase-3 and caspase-7, an increase in caspase-3 and 9 activities, and degradation of poly(ADP-ribose polymerase protein. Furthermore, quercetin activated JNK and increased the expression of p53, which translocated to the mitochondria and simultaneously led to the release of cytochrome c from mitochondria to the cytosol. We also found that quercetin induced autophagy. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in U373MG cells, indicating that quercetin induced protective autopagy in U373MG cells.

  6. Quercetin induces mitochondrial mediated apoptosis and protective autophagy in human glioblastoma U373MG cells.

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    Kim, Hyeonji; Moon, Jeong Yong; Ahn, Kwang Seok; Cho, Somi Kim

    2013-01-01

    Quercetin is a dietary flavonoid with known antitumor effects against several types of cancers by promoting apoptotic cell death and inducing cell cycle arrest. However, U373MG malignant glioma cells expressing mutant p53 are resistant to a 24 h quercetin treatment. In this study, the anticancer effect of quercetin was reevaluated in U373MG cells, and quercetin was found to be significantly effective in inhibiting proliferation of U373MG cells in a concentration-dependent manner after 48 and 72 h of incubation. Quercetin induced U373MG cell death through apoptosis, as evidenced by the increased number of cells in the sub-G1 phase, the appearance of fragmented nuclei, decreased mitochondrial membrane potential, proteolytic activation of caspase-3 and caspase-7, an increase in caspase-3 and 9 activities, and degradation of poly(ADP-ribose) polymerase protein. Furthermore, quercetin activated JNK and increased the expression of p53, which translocated to the mitochondria and simultaneously led to the release of cytochrome c from mitochondria to the cytosol. We also found that quercetin induced autophagy. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in U373MG cells, indicating that quercetin induced protective autopagy in U373MG cells.

  7. PINK1-Parkin-Mediated Mitophagy Protects Mitochondrial Integrity and Prevents Metabolic Stress-Induced Endothelial Injury.

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    Weiwei Wu

    Full Text Available Mitochondrial injury and dysfunction, a significant feature in metabolic syndrome, triggers endothelial cell dysfunction and cell death. Increasing evidence suggests that mitophagy, a process of autophagic turnover of damaged mitochondria, maintains mitochondrial integrity. PINK1 (phosphatase and tensin homolog (PTEN-induced putative kinase 1 and Parkin signaling is a key pathway in mitophagy control. In this study, we examined whether this pathway could protect mitochondria under metabolic stress. We found that palmitic acid (PA induced significant mitophagy and activated PINK1 and Parkin in endothelial cells. Knocking down PINK1 or Parkin reduced mitophagy, leading to impaired clearance of damaged mitochondria and intracellular accumulation of mitochondrial fragments. Furthermore, PINK1 and Parkin prevented PA-induced mitochondrial dysfunction, ROS production and apoptosis. Finally, we show that PINK1 and Parkin were up-regulated in vascular wall of obese mice and diabetic mice. Our study demonstrates that PINK1-Parkin pathway is activated in response to metabolic stress. Through induction of mitophagy, this pathway protects mitochondrial integrity and prevents metabolic stress-induced endothelial injury.

  8. Effect of mitochondrial potassium channel on the renal protection mediated by sodium thiosulfate against ethylene glycol induced nephrolithiasis in rat model

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    N. Baldev

    2015-12-01

    Full Text Available Purpose: Sodium thiosulfate (STS is clinically reported to be a promising drug in preventing nephrolithiasis. However, its mechanism of action remains unclear. In the present study, we investigated the role of mitochondrial KATP channel in the renal protection mediated by STS. Materials and Methods: Nephrolithiasis was induced in Wistar rats by administrating 0.4% ethylene glycol (EG along with 1% ammonium chloride for one week in drinking water followed by only 0.75% EG for two weeks. Treatment groups received STS, mitochondrial KATP channel opener and closer exclusively or in combination with STS for two weeks. Results: Animals treated with STS showed normal renal tissue architecture, supported by near normal serum creatinine, urea and ALP activity. Diazoxide (mitochondria KATP channel opening treatment to the animal also showed normal renal tissue histology and improved serum chemistry. However, an opposite result was shown by glibenclamide (mitochondria KATP channel closer treated rats. STS administered along with diazoxide negated the renal protection rendered by diazoxide alone, while it imparted protection to the glibenclamide treated rats, formulating a mitochondria modulated STS action. Conclusion: The present study confirmed that STS render renal protection not only through chelation and antioxidant effect but also by modulating the mitochondrial KATP channel for preventing urolithiasis.

  9. DNaseI Protects against Paraquat-Induced Acute Lung Injury and Pulmonary Fibrosis Mediated by Mitochondrial DNA

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    Guo Li

    2015-01-01

    Full Text Available Background. Paraquat (PQ poisoning is a lethal toxicological challenge that served as a disease model of acute lung injury and pulmonary fibrosis, but the mechanism is undetermined and no effective treatment has been discovered. Methods and Findings. We demonstrated that PQ injures mitochondria and leads to mtDNA release. The mtDNA mediated PBMC recruitment and stimulated the alveolar epithelial cell production of TGF-β1 in vitro. The levels of mtDNA in circulation and bronchial alveolar lavage fluid (BALF were elevated in a mouse of PQ-induced lung injury. DNaseI could protect PQ-induced lung injury and significantly improved survival. Acute lung injury markers, such as TNFα, IL-1β, and IL-6, and marker of fibrosis, collagen I, were downregulated in parallel with the elimination of mtDNA by DNaseI. These data indicate a possible mechanism for PQ-induced, mtDNA-mediated lung injury, which may be shared by other causes of lung injury, as suggested by the same protective effect of DNaseI in bleomycin-induced lung injury model. Interestingly, increased mtDNA in the BALF of patients with amyopathic dermatomyositis-interstitial lung disease can be appreciated. Conclusions. DNaseI targeting mtDNA may be a promising approach for the treatment of PQ-induced acute lung injury and pulmonary fibrosis that merits fast tracking through clinical trials.

  10. Long-term Aβ exposure augments mCa2+-independent mROS-mediated depletion of cardiolipin for the shift of a lethal transient mitochondrial permeability transition to its permanent mode in NARP cybrids: a protective targeting of melatonin.

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    Hsiao, Chia-Wei; Peng, Tsung-I; Peng, Alexander C; Reiter, Russel J; Tanaka, Masashi; Lai, Yiu-Kay; Jou, Mei-Jie

    2013-01-01

    Mitochondrial dysfunction is a hallmark of amyloid β-peptide (Aβ)-induced neurodegeneration of Alzheimer's disease (AD). This study investigated whether mtDNA T8993G mutation-induced complex V inhibition, clinically associated with neurological muscle weakness, ataxia, and retinitis pigmentosa (NARP), is a potential risk factor for AD and the pathological link for long-term exposure of Aβ-induced mitochondrial toxicity and apoptosis in NARP cybrids. Using noninvasive fluorescence probe-coupled laser scanning imaging microscopy and NARP cybrids harboring 98% mutant genes along with its parental 143B osteosarcoma cells, we demonstrated that Aβ-augmented mitochondrial Ca(2+) (mCa(2+))-independent mitochondrial reactive oxygen species (mROS) formation for a cardiolipin (CL, a major mitochondrial protective phospholipid)-dependent lethal modulation of the mitochondrial permeability transition (MPT). Aβ augmented not only the amount but also the propagation rate of mROS-induced mROS formation to significantly depolarize mitochondrial membrane potential (∆Ψ(m)) and reduce mCa(2+) stress. Aβ-augmented mROS oxidized and depleted CL, thereby enhances mitochondrial fission and movement retardation, which promoted the NARP-augmented lethal transient-MPT (t-MPT) to switch to its irreversible mode of permanent-MPT (p-MPT). Interestingly, melatonin, a multiple mitochondrial protector, markedly reduced Aβ-augmented mROS formation and therefore significantly reduced mROS-mediated depolarization of ∆Ψ(m), fission of mitochondria and retardation of mitochondrial movement to stabilize CL and hence the MPT. In the presence of melatonin, Aβ-promoted p-MPT was reversed to a protective t-MPT, which preserved ∆Ψ(m) and lowered elevated mCa(2+) to sublethal levels for an enhanced mCa(2+)-dependent O(2) consumption. Thus, melatonin may potentially rescue AD patients associated with NARP symptoms.

  11. Protective effects of exercise in metabolic disorders are mediated by inhibition of mitochondrial-derived sterile inflammation.

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    Peeri, Maghsoud; Amiri, Shayan

    2015-12-01

    While beneficial properties of physical activity and exercise on human health have been extensively reported in literature, the exact mechanism(s) underpinning impacts of exercise are not well understood. Focusing on metabolic disorders, as the main causes of social and economic burden in current century, exercise exhibited promising effects in prevention, alleviation and retardation of these disorders including, type 2 diabetes (T2D), Alzheimer's disease (AD), major depressive disorder (MDD) and obesity. Recent evidence has unmasked the role of mitochondrial dysfunction and chronic inflammation in pathophysiology of these disorders. Despite of the wealth of research on the etiology of metabolic disorders, intimate connections between these diseases, complex pathophysiology and their comorbidity still remains a challenging dilemma. In addition, although physical activity has improving effects on human health, it is not clear that how exercise is able to exert its modulatory effects on outcomes of metabolic disorders. Among several mechanisms, we assumed the hypothesis that exercise mitigates the production of mitochondrial-induced reactive oxygen species (ROS) and danger associated molecular patterns (DAMPs) as the main triggering factors for inflammasome formation. Since inflammasomes are of highly deleterious molecules relevant to pathogenesis of metabolic disorders, we hypothesized that beneficial effects of exercise may be associated with its ability to enhance the mitochondrial biogenesis and glucose transportation through generation of brain derived neurotrophic factor (BDNF). Also, we proposed that boosting impact of exercise on autophagy process accelerates the elimination of damaged mitochondria and thus, results in considerable decrease in production of ROS and DAMPs and consequently sterile inflammation.

  12. Melatonin protects against common deletion of mitochondrial DNA-augmented mitochondrial oxidative stress and apoptosis.

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    Jou, Mei-Jie; Peng, Tsung-I; Yu, Pai-Zu; Jou, Shuo-Bin; Reiter, Russel J; Chen, Jin-Yi; Wu, Hong-Yueh; Chen, Chih-Chun; Hsu, Lee-Fen

    2007-11-01

    Defected mitochondrial respiratory chain (RC), in addition to causing a severe ATP deficiency, often augments reactive oxygen species (ROS) generation in mitochondria (mROS) which enhances pathological conditions and diseases. Previously, we demonstrated a potent endogenously RC defect-augmented mROS associated dose-dependently with a commonly seen large-scale deletion of 4977 base pairs of mitochondrial DNA (mtDNA), i.e. the common deletion (CD). As current treatments for CD-associated diseases are rather supplementary and ineffective, we investigated whether melatonin, a potential mitochondrial protector, provides beneficial protection for CD-augmented mitochondrial oxidative stress and apoptosis particularly upon the induction of a secondary oxidative stress. Detailed mechanistic investigations were performed by using laser scanning dual fluorescence imaging microscopy to provide precise spatial and temporal resolution of mitochondrial events at single cell level. We demonstrate, for the first time, that melatonin significantly prevents CD-augmented mROS formation under basal conditions as well as at early time-points upon secondary oxidative stress induced by H2O2 exposure. Thus, melatonin prevents mROS-mediated depolarization of mitochondrial membrane potential (DeltaPsim) and subsequent opening of the mitochondrial permeability transition pore (MPTP) and cytochrome c release. Moreover, melatonin prevents depletion of cardiolipin which appears to be crucial for postponing later MPTP opening, disruption of the mitochondrial membrane and apoptosis. Finally, the protection provided by melatonin is superior to those caused by the suppression of mitochondrial Ca2+ regulators including the mitochondrial Na+-Ca2) exchanger, the MPTP, and the mitochondrial Ca2+ uniporter and by antioxidants including vitamin E and mitochondria-targeted coenzyme Q, MitoQ. As RC defect-augmented endogenous mitochondrial oxidative stress is centrally involved in a variety of pathological

  13. Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics

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    Dun-Xian Tan

    2016-12-01

    Full Text Available Melatonin has been speculated to be mainly synthesized by mitochondria. This speculation is supported by the recent discovery that aralkylamine N-acetyltransferase/serotonin N-acetyltransferase (AANAT/SNAT is localized in mitochondria of oocytes and the isolated mitochondria generate melatonin. We have also speculated that melatonin is a mitochondria-targeted antioxidant. It accumulates in mitochondria with high concentration against a concentration gradient. This is probably achieved by an active transportation via mitochondrial melatonin transporter(s. Melatonin protects mitochondria by scavenging reactive oxygen species (ROS, inhibiting the mitochondrial permeability transition pore (MPTP, and activating uncoupling proteins (UCPs. Thus, melatonin maintains the optimal mitochondrial membrane potential and preserves mitochondrial functions. In addition, mitochondrial biogenesis and dynamics is also regulated by melatonin. In most cases, melatonin reduces mitochondrial fission and elevates their fusion. Mitochondrial dynamics exhibit an oscillatory pattern which matches the melatonin circadian secretory rhythm in pinealeocytes and probably in other cells. Recently, melatonin has been found to promote mitophagy and improve homeostasis of mitochondria.

  14. Selenium-enriched Spirulina protects INS-1E pancreatic beta cells from human islet amyloid polypeptide-induced apoptosis through suppression of ROS-mediated mitochondrial dysfunction and PI3/AKT pathway.

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    Li, Xiao-Ling; Wong, Yum-Shing; Xu, Gang; Chan, Juliana C N

    2015-06-01

    Human islet amyloid polypeptide (hIAPP) aggregation is linked to loss of pancreatic beta cells in type 2 diabetes, in part due to oxidative stress. Currently, little is known about the effects of selenium-enriched Spirulina on beta cells with the presence of hIAPP. In this study, INS-1E rat insulinoma cells were used as a model to evaluate in vitro protective effects of Se-enriched Spirulina extract (Se-SE) against hIAPP-induced cell death, as well as the underlying mechanisms. Flow cytometric analysis was used to evaluate cell apoptosis, mitochondrial membrane potential (ΔΨm) and ROS generation. Caspase activity was measured using a fluorometric method. Western blotting was applied to detect protein expression. Our results showed that exposure of INS-1E cells to hIAPP resulted in cell viability loss, LDH release and appearance of sub-G peak. However, cytotoxicity of hIAPP was significantly attenuated by co-treatment with Se-SE. Se-SE also inhibited hIAPP-induced activation of caspase-3, -8 and -9. Additionally, hIAPP-induced accumulation of ROS and superoxide was suppressed by co-treatment with Se-SE. Moreover, Se-SE was able to prevent hIAPP-induced depletion of ΔΨm and intracellular ATP, reduction in mitochondrial mass, changes in the expression of Bcl-2 family members, release of mitochondrial apoptogenic factors. Furthermore, hIAPP-mediated AKT inhibition was restored by co-treatment with Se-SE. Our results showed that Se-SE protects INS-1E cells from hIAPP-induced cell death through preventing ROS overproduction, mitochondrial dysfunction and modulating PI3K/AKT pathway.

  15. Taurine protects HK-2 cells from oxidized LDL-induced cytotoxicity via the ROS-mediated mitochondrial and p53-related apoptotic pathways

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    Chang, Chun-Yu [Graduate Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Chao-Yu [School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan (China); Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan (China); School of Medicine, Chung Shan Medical University, Taichung, Taiwan (China); Kang, Chao-Kai [Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, (China); Sher, Yuh-Pyng [Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan (China); Center for Molecular Medicine, China Medical University Hospital, Taichung 404, Taiwan (China); Sheu, Wayne H.-H. [Graduate Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan (China); School of Medicine, National Yang Ming University, Taipei, Taiwan (China); School of Medicine, National Defense Medical Center, Taipei, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Graduate Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Lee, Tsung-Han, E-mail: thlee@email.nchu.edu.tw [Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, (China); Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Department of Biological Science and Technology, China Medical University, Taichung, Taiwan (China)

    2014-09-15

    Oxidized LDL (oxLDL) induces a pro-oxidative environment and promotes apoptosis, causing the progression of renal diseases in humans. Taurine is a semi-essential amino acid in mammals and has been shown to be a potent endogenous antioxidant. The kidney plays a pivotal role in maintaining the balance of taurine. However, the mechanisms underlying the protective effects of taurine against oxLDL-induced injury in renal epithelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effects of taurine on human proximal tubular epithelial (HK-2) cells exposed to oxLDL and explored the related mechanisms. We observed that oxLDL increased the contents of ROS and of malondialdehyde (MDA), which is a lipid peroxidation by-product that acts as an indicator of the cellular oxidation status. In addition, oxLDL induced cell death and apoptosis in HK-2 cells. Pretreatment with taurine at 100 μM significantly attenuated the oxLDL-induced cytotoxicity. We determined that oxLDL triggered the phosphorylation of ERK and, in turn, the activation of p53 and other apoptosis-related events, including calcium accumulation, destabilization of the mitochondrial permeability and disruption of the balance between pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins. The malfunctions induced by oxLDL were effectively blocked by taurine. Thus, our results suggested that taurine exhibits potential therapeutic activity by preventing oxLDL-induced nephrotoxicity. The inhibition of oxLDL-induced epithelial apoptosis by taurine was at least partially due to its anti-oxidant activity and its ability to modulate the ERK and p53 apoptotic pathways. - Highlights: • Oxidized LDL induced cytotoxicity and apoptosis in HK-2 cells. • Pretreatment with taurine attenuated oxLDL-induced nephrotoxicity. • Taurine protected against renal damages through inhibition of ROS generation. • Taurine prevented apoptosis through modulation of the p53 phosphorylation.

  16. Protective efficacy of vitamins C and E on p,p'-DDT-induced cytotoxicity via the ROS-mediated mitochondrial pathway and NF-κB/FasL pathway.

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    Jin, Xiaoting; Song, Li; Liu, Xiangyuan; Chen, Meilan; Li, Zhuoyu; Cheng, Long; Ren, Hua

    2014-01-01

    Dichlorodiphenoxytrichloroethane (DDT) is a known persistent organic pollutant and liver damage toxicant. However, there has been little emphasis on the mechanism underlying liver damage toxicity of DDT and the relevant effective inhibitors. Hence, the present study was conducted to explore the protective effects of vitamin C (VC) and vitamin E (VE) on the cytotoxicity of DDT in HL-7702 cells and elaborate the specific molecular mechanisms. The results demonstrated that p,p'-DDT exposure at over 10 µM depleted cell viability of HL-7702 cells and led to cell apoptotic. p,p'-DDT treatment elevated the level of reactive oxygen species (ROS) generation, induced mitochondrial membrane potential, and released cytochrome c into the cytosol, with subsequent elevations of Bax and p53, along with suppression of Bcl-2. In addition, the activations of caspase-3 and -8 were triggered. Furthermore, p,p'-DDT promoted the expressions of NF-κB and FasL. When the cells were exposed to the NF-κB inhibitor (PDTC), the up-regulated expression of FasL was attenuated. Strikingly, these alterations caused by DDT treatment were prevented or reversed by the addition of VC or VE, and the protective effects of co-treatment with VC and VE were higher than the single supplement with p,p'-DDT. Taken together, these findings provide novel experimental evidences supporting that VC or/and VE could reduce p,p'-DDT-induced cytotoxicity of HL-7702 cells via the ROS-mediated mitochondrial pathway and NF-κB/FasL pathway.

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

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    Hu, Hongtao; Li, Mo

    2016-09-01

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

  18. Mitochondrial function in neuronal cells depends on p97/VCP/Cdc48-mediated quality control

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    Lei eFang

    2015-02-01

    Full Text Available Maintaining mitochondrial function is essential for neuronal survival and offers protection against neurodegeneration. Ubiquitin-mediated, proteasome-dependent protein degradation in the form of outer mitochondrial membrane associated degradation (OMMAD was shown to play roles in maintenance of mitochondria on the level of proteostasis, but also mitophagy and cell death. Recently, the AAA-ATPase p97/VCP/Cdc48 was recognized as part of OMMAD acting as retrotranslocase of ubiquitinated mitochondrial proteins for proteasomal degradation. Thus, p97 likely plays a major role in mitochondrial maintenance. Support for this notion comes from mitochondrial dysfunction associated with amyotrophic lateral sclerosis and hereditary inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia (IBMPFD caused by p97 mutation. Using SH-SY5Y cells stably expressing p97 or dominant-negative p97QQ treated with mitochondrial toxins rotenone, 6-OHDA, or Aβ-peptide as model for neuronal cells suffering from mitochondrial dysfunction, we found mitochondrial fragmentation under normal and stress conditions was significantly increased upon inactivation of p97. Furthermore, inactivation of p97 resulted in loss of mitochondrial membrane potential and increased production of reactive oxygen species (ROS. Under additional stress conditions, loss of mitochondrial membrane potential and increased ROS production was even more pronounced. Loss of mitochondrial fidelity upon inactivation of p97 was likely due to disturbed maintenance of mitochondrial proteostasis as the employed treatments neither induced mitophagy nor cell death. This was supported by the accumulation of oxidatively-damaged proteins on mitochondria in response to p97 inactivation. Dysfunction of p97 under normal and stress conditions in neuron-like cells severely impacts mitochondrial function, thus supporting for the first time a role for p97 as a major component of mitochondrial

  19. Protective effects of 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside in the MPTP-induced mouse model of Parkinson's disease: Involvement of reactive oxygen species-mediated JNK, P38 and mitochondrial pathways.

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    He, Hong; Wang, Songhai; Tian, Jiyu; Chen, Lei; Zhang, Wei; Zhao, Junjie; Tang, Haifeng; Zhang, Xiaojun; Chen, Jianzong

    2015-11-15

    Parkinson's disease (PD) is characterized by the selective death of dopaminergic neurons in the substantia nigra pars compacta. Oxidative stress-induced neuron loss is thought to play a crucial role in the pathogenesis of PD. Previous work from our group suggests that 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from a traditional Chinese herb, Polygonum multiflorum thunb, can attenuate 1-methyl-4-phenyl pyridium-induced apoptosis in the neuronal cell line PC12, by inhibiting reactive oxygen species generation and modulating c-Jun N-terminal kinases (JNK) activation. Here, we investigated the protective effects of TSG against 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP)-induced loss of tyrosine hydroxylase positive cells in mice and the underlying mechanisms. The results showed that MPTP-induced loss of tyrosine hydroxylase positive cells and reactive oxygen species generation were prevented by TSG in a dose-dependent manner. The reactive oxygen species scavenger N-acetylcysteine could also mitigate reactive oxygen species generation. Moreover, JNK and P38 were activated by MPTP, but extracellular signal-regulated protein kinases phosphorylation did not change after MPTP treatment. TSG at different doses blocked the activation of JNK and P38. The protective effect of TSG was also associated with downregulation of the bax/bcl-2 ratio, reversed the release of cytochrome c and smac, and inhibited the activation of caspase-3, -6, and -9 induced by MPTP. In conclusion, our studies demonstrated that the protective effects of TSG in the MPTP-induced mouse model of PD are involved, at least in part, in controlling reactive oxygen species-mediated JNK, P38, and mitochondrial pathways.

  20. Protective role of melatonin in mitochondrial dysfunction and related disorders.

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    Paradies, Giuseppe; Paradies, Valeria; Ruggiero, Francesca M; Petrosillo, Giuseppe

    2015-06-01

    Mitochondria are the powerhouse of the eukaryotic cell through their use of oxidative phosphorylation to generate ATP. Mitochondrial dysfunction is considered an important contributing factor in a variety of physiopathological situations such as aging, heart ischemia/reperfusion injury, diabetes and several neurodegenerative and cardiovascular diseases, as well as in cell death. Increased formation of reactive oxygen species, altered respiratory chain complexes activity and opening of the mitochondrial permeability transition pore have been suggested as possible factors responsible for impaired mitochondrial function. Therefore, preventing mitochondrial dysfunction could be an effective therapeutic strategy against cellular degenerative processes. Cardiolipin is a unique phospholipid located at the level of inner mitochondrial membrane where it plays an important role in mitochondrial bioenergetics, as well as in cell death. Cardiolipin abnormalities have been associated with mitochondrial dysfunction in a variety of pathological conditions and aging. Melatonin, the major secretory product of the pineal gland, is a well-known antioxidant agent and thus an effective protector of mitochondrial bioenergetic function. Melatonin was reported to prevent mitochondrial dysfunction from oxidative damage by preserving cardiolipin integrity, and this may explain, at least in part, the beneficial effect of this compound in mitochondrial physiopathology. In this article, mechanisms through which melatonin exerts its protective role in mitochondrial dysfunction and related disorders are reviewed.

  1. Intermittent hypoxia protects cerebral mitochondrial function from calcium overload.

    Science.gov (United States)

    Chen, Jian; Liao, Weigong; Gao, Wenxiang; Huang, Jian; Gao, Yuqi

    2013-12-01

    Hypoxia leads to Ca(2+) overload and results in mitochondrial uncoupling, decreased ATP synthesis, and neuronal death. Inhibition of mitochondrial Ca(2+) overload protects mitochondrial function after hypoxia. The present study was aimed to investigate the effect of intermittent hypoxia on mitochondrial function and mitochondrial tolerance to Ca(2+) overload. Wistar rats were divided into control and intermittent hypoxia (IH) groups. The IH group was subject to hypoxia for 4 h daily in a hypobaric cabin (5,000 m) for 7 days. Brain mitochondria were isolated on day 7 following hypoxia. The baseline mitochondrial functions, such as ST3, ST4, and respiratory control ratio (RCR = ST3/ST4), were measured using a Clark-type oxygen electrode. Mitochondrial adenine nucleotide concentrations were measured by HPLC. Mitochondrial membrane potential was determined by measuring rhodamine 123 (Rh-123) fluorescence in the absence and presence of high Ca(2+) concentration (0.1 M), which simulates Ca(2+) overload. Our results revealed that IH did not affect mitochondrial respiratory functions, but led to a reduction in AMP and an increase in ADP concentrations in mitochondria. Both control and IH groups demonstrated decreased mitochondrial membrane potential in the presence of high Ca(2+) (0.1 M), while the IH group showed a relative higher mitochondrial membrane potential. These results indicated that the neuroprotective effect of intermittent hypoxia was resulted partly from preserving mitochondrial membrane potential, and increasing mitochondrial tolerance to high calcium levels. The increased ADP and decreased AMP in mitochondria following intermittent hypoxia may be a mechanism underlying this protection.

  2. Mitochondrial inheritance is mediated by microtubules in mammalian cell division.

    Science.gov (United States)

    Lawrence, Elizabeth; Mandato, Craig

    2013-11-01

    The mitochondrial network fragments and becomes uniformly dispersed within the cytoplasm when mammalian cells enter mitosis. Such morphology and distribution of mitochondria was previously thought to facilitate the stochastic inheritance of mitochondria by daughter cells. In contrast, we recently reported that mitochondria in dividing mammalian cells are inherited by an ordered mechanism of inheritance mediated by microtubules. We showed that mitochondria are progressively enriched at the cell equator and depleted at the poles throughout division. Furthermore, the mitochondrial distribution during division is dependent on microtubules, indicating an ordered inheritance strategy. The microtubule-mediated positioning of mitochondria in dividing mammalian cells may have functional consequences for cell division and/or mitochondrial inheritance.

  3. GPA protects the nigrostriatal dopamine system by enhancing mitochondrial function.

    Science.gov (United States)

    Horvath, Tamas L; Erion, Derek M; Elsworth, John D; Roth, Robert H; Shulman, Gerald I; Andrews, Zane B

    2011-07-01

    Guanidinopropionic acid (GPA) increases AMPK activity, mitochondrial function and biogenesis in muscle and improves physiological function, for example during aging. Mitochondrial dysfunction is a major contributor to the pathogenesis of Parkinson's disease. Here we tested whether GPA prevents neurodegeneration of the nigrostriatal dopamine system in MPTP-treated mice. Mice were fed a diet of 1% GPA or normal chow for 4 weeks and then treated with either MPTP or saline. Indices of nigrostriatal function were examined by HPLC, immunohistochemistry, stereology, electron microscopy and mitochondrial respiration. MPTP intoxication decreased TH neurons in the SNpc of normal chow-fed mice; however GPA-fed mice remarkably exhibited no loss of TH neurons in the SNpc. MPTP caused a decrease in striatal dopamine of both normal chow- and GPA-fed mice, although this effect was significantly attenuated in GPA-fed mice. GPA-fed mice showed increased AMPK activity, mitochondrial respiration and mitochondrial number in nigrostriatal TH neurons, suggesting that the neuroprotective effects of GPA involved AMPK-dependent increases in mitochondrial function and biogenesis. MPTP treatment produced a decrease in mitochondrial number and volume in normal chow-fed mice but not GPA-fed mice. Our results show the neuroprotective properties of GPA in a mouse model of Parkinson's disease are partially mediated by AMPK and mitochondrial function. Mitochondrial dysfunction is a common problem in neurodegeneration and thus GPA may slow disease progression in other models of neurodegeneration. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Mitochondrial approaches to protect against cardiac ischemia and reperfusion injury

    Directory of Open Access Journals (Sweden)

    Amadou K.S. Camara

    2011-04-01

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

  5. Mechanisms of ER Stress-Mediated Mitochondrial Membrane Permeabilization.

    LENUS (Irish Health Repository)

    Gupta, Sanjeev

    2010-01-01

    During apoptosis, the process of mitochondrial outer membrane permeabilization (MOMP) represents a point-of-no-return as it commits the cell to death. Here we have assessed the role of caspases, Bcl-2 family members and the mitochondrial permeability transition pore on ER stress-induced MOMP and subsequent cell death. Induction of ER stress leads to upregulation of several genes such as Grp78, Edem1, Erp72, Atf4, Wars, Herp, p58ipk, and ERdj4 and leads to caspase activation, release of mitochondrial intermembrane proteins and dissipation of mitochondrial transmembrane potential (DeltaPsim). Mouse embryonic fibroblasts (MEFs) from caspase-9, -2 and, -3 knock-out mice were resistant to ER stress-induced apoptosis which correlated with decreased processing of pro-caspase-3 and -9. Furthermore, pretreatment of cells with caspase inhibitors (Boc-D.fmk and DEVD.fmk) attenuated ER stress-induced loss of DeltaPsim. However, only deficiency of caspase-9 and -2 could prevent ER stress-mediated loss of DeltaPsim. Bcl-2 overexpression or pretreatment of cells with the cell permeable BH4 domain (BH4-Tat) or the mitochondrial permeability transition pore inhibitors, bongkrekic acid or cyclosporine A, attenuated the ER stress-induced loss of DeltaPsim. These data suggest a role for caspase-9 and -2, Bcl-2 family members and the mitochondrial permeability transition pore in loss of mitochondrial membrane potential during ER stress-induced apoptosis.

  6. 14,15-EET promotes mitochondrial biogenesis and protects cortical neurons against oxygen/glucose deprivation-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lai; Chen, Man; Yuan, Lin; Xiang, Yuting [Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing (China); Zheng, Ruimao, E-mail: rmzheng@pku.edu.cn [Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing (China); Zhu, Shigong, E-mail: sgzhu@bjmu.edu.cn [Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing (China)

    2014-07-18

    Highlights: • 14,15-EET inhibits OGD-induced apoptosis in cortical neurons. • Mitochondrial biogenesis of cortical neurons is promoted by 14,15-EET. • 14,15-EET preserves mitochondrial function of cortical neurons under OGD. • CREB mediates effect of 14,15-EET on mitochondrial biogenesis and function. - Abstract: 14,15-Epoxyeicosatrienoic acid (14,15-EET), a metabolite of arachidonic acid, is enriched in the brain cortex and exerts protective effect against neuronal apoptosis induced by ischemia/reperfusion. Although apoptosis has been well recognized to be closely associated with mitochondrial biogenesis and function, it is still unclear whether the neuroprotective effect of 14,15-EET is mediated by promotion of mitochondrial biogenesis and function in cortical neurons under the condition of oxygen–glucose deprivation (OGD). In this study, we found that 14,15-EET improved cell viability and inhibited apoptosis of cortical neurons. 14,15-EET significantly increased the mitochondrial mass and the ratio of mitochondrial DNA to nuclear DNA. Key makers of mitochondrial biogenesis, peroxisome proliferator activator receptor gamma-coactivator 1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), were elevated at both mRNA and protein levels in the cortical neurons treated with 14,15-EET. Moreover, 14,15-EET markedly attenuated the decline of mitochondrial membrane potential, reduced ROS, while increased ATP synthesis. Knockdown of cAMP-response element binding protein (CREB) by siRNA blunted the up-regulation of PGC-1α and NRF-1 stimulated by 14,15-EET, and consequently abolished the neuroprotective effect of 14,15-EET. Our results indicate that 14,15-EET protects neurons from OGD-induced apoptosis by promoting mitochondrial biogenesis and function through CREB mediated activation of PGC-1α and NRF-1.

  7. The antileishmanial activity of xanthohumol is mediated by mitochondrial inhibition.

    Science.gov (United States)

    Monzote, Lianet; Lackova, Alexandra; Staniek, Katrin; Steinbauer, Silvia; Pichler, Gerald; Jäger, Walter; Gille, Lars

    2016-12-12

    Xanthohumol (Xan) is a natural constituent of human nutrition. Little is known about its actions on leishmanial parasites and their mitochondria as putative target. Therefore, we determined the antileishmanial activity of Xan and resveratrol (Res, as alternative compound with antileishmanial activity) with respect to mitochondria in Leishmania amazonensis promastigotes/amastigotes (LaP/LaA) in comparison with their activity in peritoneal macrophages from mouse (PMM) and macrophage cell line J774A.1 (J774). Mechanistic studies were conducted in Leishmania tarentolae promastigotes (LtP) and mitochondrial fractions isolated from LtP. Xan and Res demonstrated antileishmanial activity in LaA [half inhibitory concentration (IC50): Xan 7 µ m, Res 14 µ m]; while they had less influence on the viability of PMM (IC50: Xan 70 µ m, Res >438 µ m). In contrast to Res, Xan strongly inhibited oxygen consumption in Leishmania (LtP) but not in J774 cells. This was based on the inhibition of the mitochondrial electron transfer complex II/III by Xan, which was less pronounced with Res. Neither Xan nor Res increased mitochondrial superoxide release in LtP, while both decreased the mitochondrial membrane potential in LtP. Bioenergetic studies showed that LtP mitochondria have no spare respiratory capacity in contrast to mitochondria in J774 cells and can therefore much less adapt to stress by mitochondrial inhibitors, such as Xan. These data show that Xan may have antileishmanial activity, which is mediated by mitochondrial inhibition.

  8. Iron-Starvation-Induced Mitophagy Mediates Lifespan Extension upon Mitochondrial Stress in C. elegans.

    Science.gov (United States)

    Schiavi, Alfonso; Maglioni, Silvia; Palikaras, Konstantinos; Shaik, Anjumara; Strappazzon, Flavie; Brinkmann, Vanessa; Torgovnick, Alessandro; Castelein, Natascha; De Henau, Sasha; Braeckman, Bart P; Cecconi, Francesco; Tavernarakis, Nektarios; Ventura, Natascia

    2015-07-20

    Frataxin is a nuclear-encoded mitochondrial protein involved in the biogenesis of Fe-S-cluster-containing proteins and consequently in the functionality of the mitochondrial respiratory chain. Similar to other proteins that regulate mitochondrial respiration, severe frataxin deficiency leads to pathology in humans--Friedreich's ataxia, a life-threatening neurodegenerative disorder--and to developmental arrest in the nematode C. elegans. Interestingly, partial frataxin depletion extends C. elegans lifespan, and a similar anti-aging effect is prompted by reduced expression of other mitochondrial regulatory proteins from yeast to mammals. The beneficial adaptive responses to mild mitochondrial stress are still largely unknown and, if characterized, may suggest novel potential targets for the treatment of human mitochondria-associated, age-related disorders. Here we identify mitochondrial autophagy as an evolutionarily conserved response to frataxin silencing, and show for the first time that, similar to mammals, mitophagy is activated in C. elegans in response to mitochondrial stress in a pdr-1/Parkin-, pink-1/Pink-, and dct-1/Bnip3-dependent manner. The induction of mitophagy is part of a hypoxia-like, iron starvation response triggered upon frataxin depletion and causally involved in animal lifespan extension. We also identify non-overlapping hif-1 upstream (HIF-1-prolyl-hydroxylase) and downstream (globins) regulatory genes mediating lifespan extension upon frataxin and iron depletion. Our findings indicate that mitophagy induction is part of an adaptive iron starvation response induced as a protective mechanism against mitochondrial stress, thus suggesting novel potential therapeutic strategies for the treatment of mitochondrial-associated, age-related disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Sevoflurane post-conditioning protects primary rat cortical neurons against oxygen-glucose deprivation/resuscitation via down-regulation in mitochondrial apoptosis axis of Bid, Bim, Puma-Bax and Bak mediated by Erk1/2.

    Science.gov (United States)

    Zhang, Li-Min; Zhao, Xiao-Chun; Sun, Wen-Bo; Li, Rui; Jiang, Xiao-Jing

    2015-10-15

    Temporal post-conditioning helps provide neuroprotection against brain injury secondary to ischemia-reperfusion and is considered an effective intervention, but the exact mechanism of sevoflurane post-conditioning is unclear. The essential axis involves activator Bid, Bim, Puma (BH3s), Bax, and Bak; activates the mitochondrial death program; and might be involved in a cell death signal. Extracellular signal-related kinases 1/2 (Erk1/2) play a pivotal role in cell growth and proliferation. We hypothesized that sevoflurane post-conditioning might inhibit Bid, Bim, Puma, Bax, and Bak expression and is activated by phosphor-Erk1/2 to decrease neuronal death. To test this hypothesis, we exposed primary cortical neuron cultures to oxygen-glucose deprivation for 1h, along with resuscitation for 24h (OGD/R). MTT assays, propidium iodide uptake (PI), JC-1 fluorescence, and Western blot indicated the following: decreased cell viability (PPuma, Bax, and Bak expression with OGD/R exposure. Inhibition of Erk1/2 phosphorylation could attenuate sevoflurane post-conditioning that mediated an increase in neuronal viability and mitochondrial membrane potential, as well as a decrease in cell death and Bid, Bim, Puma, Bax, and Bak expression after OGD/R treatment. The results demonstrated that sevoflurane post-conditioning caused a marked decrease in cortical neuronal death secondary to OGD/R exposure through the downregulation of the mitochondrial apoptosis axis involving Bid, Bim, Puma, Bax, and Bak that was mediated by the phosphorylation/activation of Erk1/2.

  10. Phosphocreatine protects against LPS-induced human umbilical vein endothelial cell apoptosis by regulating mitochondrial oxidative phosphorylation.

    Science.gov (United States)

    Sun, Zhengwu; Lan, Xiaoyan; Ahsan, Anil; Xi, Yalin; Liu, Shumin; Zhang, Zonghui; Chu, Peng; Song, Yushu; Piao, Fengyuan; Peng, Jinyong; Lin, Yuan; Han, Guozhu; Tang, Zeyao

    2016-03-01

    Phosphocreatine (PCr) is an exogenous energy substance, which provides phosphate groups for adenosine triphosphate (ATP) cycle and promotes energy metabolism in cells. However, it is still unclear whether PCr has influenced on mitochondrial energy metabolism as well as oxidative phosphorylation (OXPHO) in previous studies. Therefore, the aim of the present study was to investigate the regulation of PCr on lipopolsaccharide (LPS)-induced human umbilical vein endothelial cells (HUVECs) and mitochondrial OXPHO pathway. PCr protected HUVECs against LPS-induced apoptosis by suppressing the mitochondrial permeability transition, cytosolic release of cytochrome c (Cyt C), Ca(2+), reactive oxygen species and subsequent activation of caspases, and increasing Bcl2 expression, while suppressing Bax expression. More importantly, PCr significantly improved mitochondrial swelling and membrane potential, enhanced the activities of ATP synthase and mitochondrial creatine kinase (CKmt) in creatine shuttle, influenced on respiratory chain enzymes, respiratory control ratio, phosphorus/oxygen ratio and ATP production of OXPHO. Above PCr-mediated mitochondrial events were effectively more favorable to reduced form of flavin adenine dinucleotide (FADH2) pathway than reduced form of nicotinamide-adenine dinucleotid pathway in the mitochondrial respiratory chain. Our results revealed that PCr protects against LPS-induced HUVECs apoptosis, which probably related to stabilization of intracellular energy metabolism, especially for FADH2 pathway in mitochondrial respiratory chain, ATP synthase and CKmt. Our findings suggest that PCr may play a certain role in the treatment of atherosclerosis via protecting endothelial cell function.

  11. PUMA-mediated mitochondrial apoptotic disruption by hypoxic postconditioning.

    Science.gov (United States)

    Li, YuZhen; Guo, Qi; Liu, XiuHua; Wang, Chen; Song, DanDan

    2015-08-01

    Postconditioning can reduce ischemia-reperfusion (I/R)-induced cardiomyocyte apoptosis by targeting mitochondria. p53 upregulated modulator of apoptosis (PUMA) is involved in lethal I/R injury. Here, we hypothesized that postconditioning might inhibit mitochondrial pathway-mediated cardiomyocyte apoptosis by controlling PUMA expression. The cultured neonatal rat cardiomyocytes underwent 3 h of hypoxia and 3 h of reoxygenation. Postconditioning consisted of three cycles of 5 min reoxygenation and 5 min hypoxia after prolonged hypoxia. Hypoxic postconditioning reduced the levels of PUMA mRNA and protein. Concomitantly, the loss of mitochondrial membrane potential, cytochrome c release and caspase-3 activation were decreased significantly by postconditioning. Overexpression of PUMA increased greatly not only the number of apoptotic cardiomyocytes, but also the collapse of mitochondrial membrane potential, cytochrome c release and caspase-3 activation under postconditioning condition. The data suggest that reduction of PUMA expression mediates the endogenous cardioprotective mechanisms of postconditioning by disrupting mitochondrial apoptotic pathway.

  12. Hydrogen sulfide protects HUVECs against hydrogen peroxide induced mitochondrial dysfunction and oxidative stress.

    Directory of Open Access Journals (Sweden)

    Ya-Dan Wen

    Full Text Available BACKGROUND: Hydrogen sulfide (H₂S has been shown to have cytoprotective effects in models of hypertension, ischemia/reperfusion and Alzheimer's disease. However, little is known about its effects or mechanisms of action in atherosclerosis. Therefore, in the current study we evaluated the pharmacological effects of H₂S on antioxidant defenses and mitochondria protection against hydrogen peroxide (H₂O₂ induced endothelial cells damage. METHODOLOGY AND PRINCIPAL FINDINGS: H₂S, at non-cytotoxic levels, exerts a concentration dependent protective effect in human umbilical vein endothelial cells (HUVECs exposed to H₂O₂. Analysis of ATP synthesis, mitochondrial membrane potential (ΔΨm and cytochrome c release from mitochondria indicated that mitochondrial function was preserved by pretreatment with H₂S. In contrast, in H₂O₂ exposed endothelial cells mitochondria appeared swollen or ruptured. In additional experiments, H₂S was also found to preserve the activities and protein expressions levels of the antioxidants enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in H₂O₂ exposed cells. ROS and lipid peroxidation, as assessed by measuring H₂DCFDA, dihydroethidium (DHE, diphenyl-l-pyrenylphosphine (DPPP and malonaldehyde (MDA levels, were also inhibited by H₂S treatment. Interestingly, in the current model, D, L-propargylglycine (PAG, a selective inhibitor of cystathionine γ-lyase (CSE, abolished the protective effects of H₂S donors. INNOVATION: This study is the first to show that H₂S can inhibit H₂O₂ mediated mitochondrial dysfunction in human endothelial cells by preserving antioxidant defences. SIGNIFICANCE: H₂S may protect against atherosclerosis by preventing H₂O₂ induced injury to endothelial cells. These effects appear to be mediated via the preservation of mitochondrial function and by reducing the deleterious effects of oxidative stress.

  13. Modulation of oxidative/nitrosative stress and mitochondrial protective effect of Semecarpus anacardium in diabetic rats.

    Science.gov (United States)

    Jaya, Aseervatham; Shanthi, Palanivelu; Sachdanandam, Panchanadham

    2010-04-01

    Oxidative and nitrosative stress play an important role in the complications of diabetes mellitus. Free radicals are produced when there is an electron leak in the mito-chondria and a change in the mitochondrial membrane potential. The present study was undertaken to investigate the role of Semecarpus anacardium in protecting the mito-chondria by modulating the production of reactive oxygen species and reactive nitrogen species in diabetic rats. Diabetes was induced using streptozotocin at a dose of 50 mg/kg body weight and, starting 3 days after the induction, Semecarpus anacardium nut milk extract was administered for 21 days. The same duration of study was used for control, diabetes-induced and drug control groups, together with a group treated with metformin. After the experimental period, the animals were sacrificed and the levels of superoxide, hydrogen peroxide, nitrate and nitrite were estimated. Changes in mitochondrial membrane potential, intracellular reactive oxygen species and intracellular calcium were also determined. Confocal laser microscopic images were taken for mitochondria isolated from the liver and kidneys. The results of the study revealed that Semecarpus anacardium was able to decrease the production of reactive oxygen and nitrogen species, and reverse the changes in mitochondrial membrane potential and the influx of calcium into the mitochondria. The mitochondrial protective effect may be mediated by scavenging of free radicals and complexing of metal ions by virtue of the antioxidative effect of Semecarpus anacardium.

  14. Geniposide Protects Primary Cortical Neurons against Oligomeric Aβ1-42-Induced Neurotoxicity through a Mitochondrial Pathway.

    Directory of Open Access Journals (Sweden)

    Chunhui Zhao

    Full Text Available Mitochondrial dysfunction plays a key role in the progression of Alzheimer's disease (AD. The accumulation of amyloid-beta peptide (Aβ in the brains of AD patients is thought to be closely related to neuronal mitochondrial dysfunction and oxidative stress. Therefore, protecting mitochondria from Aβ-induced neurotoxicity is an effective strategy for AD therapeutics. In a previous study, we found that geniposide, a pharmacologically active compound purified from gardenia fruit, has protective effects on oxidative stress and mitochondrial dysfunction in AD transgenic mouse models. However, whether geniposide has a protective effect on Aβ-induced neuronal dysfunction remains unknown. In the present study, we demonstrate that geniposide protects cultured primary cortical neurons from Aβ-mediated mitochondrial dysfunction by recovering ATP generation, mitochondrial membrane potential (MMP, and cytochrome c oxidase (CcO and caspase 3/9 activity; by reducing ROS production and cytochrome c leakage; as well as by inhibiting apoptosis. These findings suggest that geniposide may attenuate Aβ-induced neuronal injury by inhibiting mitochondrial dysfunction and oxidative stress.

  15. Inhibition of the mitochondrial enzyme ABAD restores the amyloid-β-mediated deregulation of estradiol.

    Directory of Open Access Journals (Sweden)

    Yun-An Lim

    Full Text Available Alzheimer's disease (AD is a conformational disease that is characterized by amyloid-β (Aβ deposition in the brain. Aβ exerts its toxicity in part by receptor-mediated interactions that cause down-stream protein misfolding and aggregation, as well as mitochondrial dysfunction. Recent reports indicate that Aβ may also interact directly with intracellular proteins such as the mitochondrial enzyme ABAD (Aβ binding alcohol dehydrogenase in executing its toxic effects. Mitochondrial dysfunction occurs early in AD, and Aβ's toxicity is in part mediated by inhibition of ABAD as shown previously with an ABAD decoy peptide. Here, we employed AG18051, a novel small ABAD-specific compound inhibitor, to investigate the role of ABAD in Aβ toxicity. Using SH-SY5Y neuroblastoma cells, we found that AG18051 partially blocked the Aβ-ABAD interaction in a pull-down assay while it also prevented the Aβ42-induced down-regulation of ABAD activity, as measured by levels of estradiol, a known hormone and product of ABAD activity. Furthermore, AG18051 is protective against Aβ42 toxicity, as measured by LDH release and MTT absorbance. Specifically, AG18051 reduced Aβ42-induced impairment of mitochondrial respiration and oxidative stress as shown by reduced ROS (reactive oxygen species levels. Guided by our previous finding of shared aspects of the toxicity of Aβ and human amylin (HA, with the latter forming aggregates in Type 2 diabetes mellitus (T2DM pancreas, we determined whether AG18051 would also confer protection from HA toxicity. We found that the inhibitor conferred only partial protection from HA toxicity indicating distinct pathomechanisms of the two amyloidogenic agents. Taken together, our results present the inhibition of ABAD by compounds such as AG18051 as a promising therapeutic strategy for the prevention and treatment of AD, and suggest levels of estradiol as a suitable read-out.

  16. Role of mitochondrial ATP-sensitive potassium channel-mediated PKC-ε in delayed protection against myocardial ischemia/reperfusion injury in isolated hearts of sevoflurane-preconditioned rats

    Directory of Open Access Journals (Sweden)

    C. Wang

    2015-06-01

    Full Text Available This study aimed to determine the role of mitochondrial adenosine triphosphate-sensitive potassium (mitoKATP channels and protein kinase C (PKC-ε in the delayed protective effects of sevoflurane preconditioning using Langendorff isolated heart perfusion models. Fifty-four isolated perfused rat hearts were randomly divided into 6 groups (n=9. The rats were exposed for 60 min to 2.5% sevoflurane (the second window of protection group, SWOP group or 33% oxygen inhalation (I/R group 24 h before coronary occlusion. The control group (CON and the sevoflurane group (SEVO group were exposed to 33% oxygen and 2.5% sevoflurane for 60 min, respectively, without coronary occlusion. The mitoKATP channel inhibitor 5-hydroxydecanoate (5-HD was given 30 min before sevoflurane preconditioning (5-HD+SWOP group. Cardiac function indices, infarct sizes, serum cardiac troponin I (cTnI concentrations, and the expression levels of phosphorylated PKC-ε (p-PKC-ε and caspase-8 were measured. Cardiac function was unchanged, p-PKC-ε expression was upregulated, caspase-8 expression was downregulated, cTnI concentrations were decreased, and the infarcts were significantly smaller (P<0.05 in the SWOP group compared with the I/R group. Cardiac function was worse, p-PKC-ε expression was downregulated, caspase-8 expression was upregulated, cTnI concentration was increased and infarcts were larger in the 5-HD+SWOP group (P<0.05 compared with the SWOP group. The results suggest that mitoKATP channels are involved in the myocardial protective effects of sevoflurane in preconditioning against I/R injury, by regulating PKC-ε phosphorylation before ischemia, and by downregulating caspase-8 during reperfusion.

  17. Role of mitochondrial ATP-sensitive potassium channel-mediated PKC-ε in delayed protection against myocardial ischemia/reperfusion injury in isolated hearts of sevoflurane-preconditioned rats

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C. [Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou (China); Institute of Neuroscience, Soochow University, Suzhou (China); Hu, S.M. [Institute of Neuroscience, Soochow University, Suzhou (China); Xie, H.; Qiao, S.G. [Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou (China); Liu, H. [Department of Anesthesiology and Pain Medicine, University of California Davis Health System, Davis, CA (United States); Liu, C.F. [Institute of Neuroscience, Soochow University, Suzhou (China)

    2015-03-27

    This study aimed to determine the role of mitochondrial adenosine triphosphate-sensitive potassium (mitoK{sub ATP}) channels and protein kinase C (PKC)-ε in the delayed protective effects of sevoflurane preconditioning using Langendorff isolated heart perfusion models. Fifty-four isolated perfused rat hearts were randomly divided into 6 groups (n=9). The rats were exposed for 60 min to 2.5% sevoflurane (the second window of protection group, SWOP group) or 33% oxygen inhalation (I/R group) 24 h before coronary occlusion. The control group (CON) and the sevoflurane group (SEVO) group were exposed to 33% oxygen and 2.5% sevoflurane for 60 min, respectively, without coronary occlusion. The mitoK{sub ATP} channel inhibitor 5-hydroxydecanoate (5-HD) was given 30 min before sevoflurane preconditioning (5-HD+SWOP group). Cardiac function indices, infarct sizes, serum cardiac troponin I (cTnI) concentrations, and the expression levels of phosphorylated PKC-ε (p-PKC-ε) and caspase-8 were measured. Cardiac function was unchanged, p-PKC-ε expression was upregulated, caspase-8 expression was downregulated, cTnI concentrations were decreased, and the infarcts were significantly smaller (P<0.05) in the SWOP group compared with the I/R group. Cardiac function was worse, p-PKC-ε expression was downregulated, caspase-8 expression was upregulated, cTnI concentration was increased and infarcts were larger in the 5-HD+SWOP group (P<0.05) compared with the SWOP group. The results suggest that mitoK{sub ATP} channels are involved in the myocardial protective effects of sevoflurane in preconditioning against I/R injury, by regulating PKC-ε phosphorylation before ischemia, and by downregulating caspase-8 during reperfusion.

  18. Functional Recovery of Human Cells Harbouring the Mitochondrial DNA Mutation MERRF A8344G via Peptide-Mediated Mitochondrial Delivery

    Directory of Open Access Journals (Sweden)

    Jui-Chih Chang

    2012-09-01

    Full Text Available We explored the feasibility of mitochondrial therapy using the cell-penetrating peptide Pep-1 to transfer mitochondrial DNA (mtDNA between cells and rescue a cybrid cell model of the mitochondrial disease myoclonic epilepsy with ragged-red fibres (MERRF syndrome. Pep-1-conjugated wild-type mitochondria isolated from parent cybrid cells incorporating a mitochondria-specific tag were used as donors for mitochondrial delivery into MERRF cybrid cells (MitoB2 and mtDNA-depleted Rho-zero cells (Mitoρ°. Forty-eight hours later, translocation of Pep-1-labelled mitochondria into the mitochondrial regions of MitoB2 and Mitoρ° host cells was observed (delivery efficiencies of 77.48 and 82.96%, respectively. These internalized mitochondria were maintained for at least 15 days in both cell types and were accompanied by mitochondrial function recovery and cell survival by preventing mitochondria-dependent cell death. Mitochondrial homeostasis analyses showed that peptide-mediated mitochondrial delivery (PMD also increased mitochondrial biogenesis in both cell types, but through distinct regulatory pathways involving mitochondrial dynamics. Dramatic decreases in mitofusin-2 (MFN2 and dynamin-related protein 1/fission 1 were observed in MitoB2 cells, while Mitoρ° cells showed a significant increase in optic atrophy 1 and MFN2. These findings suggest that PMD can be used as a potential therapeutic intervention for mitochondrial disorders.

  19. Akt protects the heart against ischaemia-reperfusion injury by modulating mitochondrial morphology.

    Science.gov (United States)

    Ong, Sang-Bing; Hall, Andrew R; Dongworth, Rachel K; Kalkhoran, Siavash; Pyakurel, Aswin; Scorrano, Luca; Hausenloy, Derek J

    2015-03-01

    The mechanism through which the protein kinase Akt (also called PKB), protects the heart against acute ischaemia-reperfusion injury (IRI) is not clear. Here, we investigate whether Akt mediates its cardioprotective effect by modulating mitochondrial morphology. Transfection of HL-1 cardiac cells with constitutively active Akt (caAkt) changed mitochondrial morphology as evidenced by an increase in the proportion of cells displaying predominantly elongated mitochondria (73 ± 5.0 % caAkt vs 49 ± 5.8 % control: N=80 cells/group; pmitochondrial permeability transition pore (MPTP) opening (by 2.4 ± 0.5 fold; N=80 cells/group: pmitochondrial morphology, MPTP opening, and cell survival post-IRI, were demonstrated with pharmacological activation of Akt using the known cardioprotective cytokine, erythropoietin (EPO). The effect of Akt on inducing mitochondrial elongation was found to be dependent on the mitochondrial fusion protein, Mitofusin-1 (Mfn1), as ablation of Mfn1 in mouse embryonic fibroblasts (MEFs) abrogated Akt-mediated mitochondrial elongation. Finally, in vivo pre-treatment with EPO reduced myocardial infarct size (as a % of the area at risk) in adult mice subjected to IRI (26.2 ± 2.6 % with EPO vs 46.1 ± 6.5 % in control; N=7/group: pmitochondrial fragmentation observed by electron microscopy in adult murine hearts subjected to ischaemia from 5.8 ± 1.0 % to 2.2 ± 1.0 % (N=5 hearts/group; pmitochondrial morphology.

  20. Sulforaphane Attenuates Gentamicin-Induced Nephrotoxicity: Role of Mitochondrial Protection

    Science.gov (United States)

    Huerta-Yepez, Sara; Medina-Campos, Omar Noel; Zatarain-Barrón, Zyanya Lucía; Hernández-Pando, Rogelio; Torres, Ismael; Tapia, Edilia; Pedraza-Chaverri, José

    2013-01-01

    Sulforaphane (SFN), an isothiocyanate naturally occurring in Cruciferae, induces cytoprotection in several tissues. Its protective effect has been associated with its ability to induce cytoprotective enzymes through an Nrf2-dependent pathway. Gentamicin (GM) is a widely used antibiotic; nephrotoxicity is the main side effect of this compound. In this study, it was investigated if SFN is able to induce protection against GM-induced nephropathy both in renal epithelial LLC-PK1 cells in culture and in rats. SFN prevented GM-induced death and loss of mitochondrial membrane potential in LLC-PK1 cells. In addition, it attenuated GM-induced renal injury (proteinuria, increases in serum creatinine, in blood urea nitrogen, and in urinary excretion on N-acetyl-β-D-glucosaminidase, and decrease in creatinine clearance and in plasma glutathione peroxidase activity) and necrosis and apoptosis in rats. The apoptotic death was associated with enhanced active caspase-9. Caspase-8 was unchanged in all the studied groups. In addition, SFN was able to prevent GM-induced protein nitration and decrease in the activity of antioxidant enzymes catalase and glutathione peroxidase in renal cortex. In conclusion, the protective effect of SFN against GM-induced acute kidney injury could be associated with the preservation in mitochondrial function that would prevent the intrinsic apoptosis and nitrosative stress. PMID:23662110

  1. Sulforaphane Attenuates Gentamicin-Induced Nephrotoxicity: Role of Mitochondrial Protection

    Directory of Open Access Journals (Sweden)

    Mario Negrette-Guzmán

    2013-01-01

    Full Text Available Sulforaphane (SFN, an isothiocyanate naturally occurring in Cruciferae, induces cytoprotection in several tissues. Its protective effect has been associated with its ability to induce cytoprotective enzymes through an Nrf2-dependent pathway. Gentamicin (GM is a widely used antibiotic; nephrotoxicity is the main side effect of this compound. In this study, it was investigated if SFN is able to induce protection against GM-induced nephropathy both in renal epithelial LLC-PK1 cells in culture and in rats. SFN prevented GM-induced death and loss of mitochondrial membrane potential in LLC-PK1 cells. In addition, it attenuated GM-induced renal injury (proteinuria, increases in serum creatinine, in blood urea nitrogen, and in urinary excretion on N-acetyl-β-D-glucosaminidase, and decrease in creatinine clearance and in plasma glutathione peroxidase activity and necrosis and apoptosis in rats. The apoptotic death was associated with enhanced active caspase-9. Caspase-8 was unchanged in all the studied groups. In addition, SFN was able to prevent GM-induced protein nitration and decrease in the activity of antioxidant enzymes catalase and glutathione peroxidase in renal cortex. In conclusion, the protective effect of SFN against GM-induced acute kidney injury could be associated with the preservation in mitochondrial function that would prevent the intrinsic apoptosis and nitrosative stress.

  2. N-acetyl cysteine protects human oral keratinocytes from Bis-GMA-induced apoptosis and cell cycle arrest by inhibiting reactive oxygen species-mediated mitochondrial dysfunction and the PI3K/Akt pathway.

    Science.gov (United States)

    Zhu, Yu; Gu, Ying-xin; Mo, Jia-ji; Shi, Jun-yu; Qiao, Shi-chong; Lai, Hong-chang

    2015-12-01

    Bisphenol-A-glycidyl methacrylate (Bis-GMA) released from dental resin materials causes various toxic effects on gingival epithelium. Thus the underlying mechanisms of its cytotoxicity should be elucidated for safety use. One potential cause of cell damage is the generation of reactive oxygen species (ROS) beyond the capacity of a balanced redox regulation. In this study, we found that exposure of human oral keratinocytes (HOKs) to Bis-GMA caused apoptosis and G1/S cell cycle arrest in parallel with an increased ROS level. Moreover, Bis-GMA induced a depletion of mitochondrial membrane potential, an increase in the Bax/Bcl-2 ratio, an activation of caspase-3 and altered expressions of cell cycle-related proteins (p21, PCNA, cyclinD1). Furthermore, the co-treatment of the ROS scavenger N-acetyl cysteine (NAC) obviously attenuated Bis-GMA-induced toxicity. Here we also evaluated the effects of Bis-GMA on the ROS-related PI3k/Akt pathway. We found that Bis-GMA inhibited the phosphorylation of Akt, whereas the amount of phosphorylated Akt was reverted to the control level in the presence of NAC. Our findings suggested that the toxic effects of Bis-GMA were related to ROS production and the antioxidant NAC effectively reduced Bis-GMA-mediated cytotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Ca2+ signals regulate mitochondrial metabolism by stimulating CREB-mediated expression of the mitochondrial Ca2+ uniporter gene MCU.

    Science.gov (United States)

    Shanmughapriya, Santhanam; Rajan, Sudarsan; Hoffman, Nicholas E; Zhang, Xueqian; Guo, Shuchi; Kolesar, Jill E; Hines, Kevin J; Ragheb, Jonathan; Jog, Neelakshi R; Caricchio, Roberto; Baba, Yoshihiro; Zhou, Yandong; Kaufman, Brett A; Cheung, Joseph Y; Kurosaki, Tomohiro; Gill, Donald L; Madesh, Muniswamy

    2015-03-03

    Cytosolic Ca2+ signals, generated through the coordinated translocation of Ca2+ across the plasma membrane (PM) and endoplasmic reticulum (ER) membrane, mediate diverse cellular responses. Mitochondrial Ca2+ is important for mitochondrial function, and when cytosolic Ca2+ concentration becomes too high, mitochondria function as cellular Ca2+ sinks. By measuring mitochondrial Ca2+ currents, we found that mitochondrial Ca2+ uptake was reduced in chicken DT40 B lymphocytes lacking either the ER-localized inositol trisphosphate receptor (IP3R), which releases Ca2+ from the ER, or Orai1 or STIM1, components of the PM-localized Ca2+ -permeable channel complex that mediates store-operated calcium entry (SOCE) in response to depletion of ER Ca2+ stores. The abundance of MCU, the pore-forming subunit of the mitochondrial Ca2+ uniporter, was reduced in cells deficient in IP3R, STIM1, or Orai1. Chromatin immunoprecipitation and promoter reporter analyses revealed that the Ca2+ -regulated transcription factor CREB (cyclic adenosine monophosphate response element-binding protein) directly bound the MCU promoter and stimulated expression. Lymphocytes deficient in IP3R, STIM1, or Orai1 exhibited altered mitochondrial metabolism, indicating that Ca2+ released from the ER and SOCE-mediated signals modulates mitochondrial function. Thus, our results showed that a transcriptional regulatory circuit involving Ca2+ -dependent activation of CREB controls the Ca2+ uptake capability of mitochondria and hence regulates mitochondrial metabolism.

  4. 14,15-EET promotes mitochondrial biogenesis and protects cortical neurons against oxygen/glucose deprivation-induced apoptosis.

    Science.gov (United States)

    Wang, Lai; Chen, Man; Yuan, Lin; Xiang, Yuting; Zheng, Ruimao; Zhu, Shigong

    2014-07-18

    14,15-Epoxyeicosatrienoic acid (14,15-EET), a metabolite of arachidonic acid, is enriched in the brain cortex and exerts protective effect against neuronal apoptosis induced by ischemia/reperfusion. Although apoptosis has been well recognized to be closely associated with mitochondrial biogenesis and function, it is still unclear whether the neuroprotective effect of 14,15-EET is mediated by promotion of mitochondrial biogenesis and function in cortical neurons under the condition of oxygen-glucose deprivation (OGD). In this study, we found that 14,15-EET improved cell viability and inhibited apoptosis of cortical neurons. 14,15-EET significantly increased the mitochondrial mass and the ratio of mitochondrial DNA to nuclear DNA. Key makers of mitochondrial biogenesis, peroxisome proliferator activator receptor gamma-coactivator 1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), were elevated at both mRNA and protein levels in the cortical neurons treated with 14,15-EET. Moreover, 14,15-EET markedly attenuated the decline of mitochondrial membrane potential, reduced ROS, while increased ATP synthesis. Knockdown of cAMP-response element binding protein (CREB) by siRNA blunted the up-regulation of PGC-1α and NRF-1 stimulated by 14,15-EET, and consequently abolished the neuroprotective effect of 14,15-EET. Our results indicate that 14,15-EET protects neurons from OGD-induced apoptosis by promoting mitochondrial biogenesis and function through CREB mediated activation of PGC-1α and NRF-1.

  5. Ursolic acid mediates photosensitization by initiating mitochondrial-dependent apoptosis

    Science.gov (United States)

    Lee, Yuan-Hao; Wang, Exing; Kumar, Neeru; Glickman, Randolph D.

    2013-02-01

    The signaling pathways PI3K/Akt and MAPK play key roles in transcription, translation and carcinogenesis, and may be activated by light exposure. These pathways may be modulated or inhibited by naturally-occurring compounds, such as the triterpenoid, ursolic acid (UA). Previously, the transcription factors p53 and NF-kB, which transactivate mitochondrial apoptosis-related genes, were shown to be differentially modulated by UA. Our current work indicates that UA causes these effects via the mTOR and insulin-mediated pathways. UA-modulated apoptosis, following exposure to UV radiation, is observed to correspond to differential levels of oxidative stress in retinal pigment epithelial (RPE) and skin melanoma (SM) cells. Flow cytometry analysis, DHE (dihydroethidium) staining and membrane permeability assay showed that UA pretreatment potentiated cell cycle arrest and radiation-induced apoptosis selectively on SM cells while DNA photo-oxidative damage (i.e. strand breakage) was reduced, presumably by some antioxidant activity of UA in RPE cells. The UA-mediated NF-κB activation in SM cells was reduced by rapamycin pretreatment, which indicates that these agents exert inter-antagonistic effects in the PI3K/Akt/mTOR pathway. In contrast, the antagonistic effect of UA on the PI3K/Akt pathway was reversed by insulin leading to greater NF-κB and p53 activation in RPE cells. MitoTracker, a mitochondrial functional assay, indicated that mitochondria in RPE cells experienced reduced oxidative stress while those in SM cells exhibited increased oxidative stress upon UA pretreatment. When rapamycin administration was followed by UA, mitochondrial oxidative stress was increased in RPE cells but decreased in SM cells. These results indicate that UA modulates p53 and NF-κB, initiating a mitogenic response to radiation that triggers mitochondria-dependent apoptosis.

  6. Metabolism. AMP-activated protein kinase mediates mitochondrial fission in response to energy stress.

    Science.gov (United States)

    Toyama, Erin Quan; Herzig, Sébastien; Courchet, Julien; Lewis, Tommy L; Losón, Oliver C; Hellberg, Kristina; Young, Nathan P; Chen, Hsiuchen; Polleux, Franck; Chan, David C; Shaw, Reuben J

    2016-01-15

    Mitochondria undergo fragmentation in response to electron transport chain (ETC) poisons and mitochondrial DNA-linked disease mutations, yet how these stimuli mechanistically connect to the mitochondrial fission and fusion machinery is poorly understood. We found that the energy-sensing adenosine monophosphate (AMP)-activated protein kinase (AMPK) is genetically required for cells to undergo rapid mitochondrial fragmentation after treatment with ETC inhibitors. Moreover, direct pharmacological activation of AMPK was sufficient to rapidly promote mitochondrial fragmentation even in the absence of mitochondrial stress. A screen for substrates of AMPK identified mitochondrial fission factor (MFF), a mitochondrial outer-membrane receptor for DRP1, the cytoplasmic guanosine triphosphatase that catalyzes mitochondrial fission. Nonphosphorylatable and phosphomimetic alleles of the AMPK sites in MFF revealed that it is a key effector of AMPK-mediated mitochondrial fission.

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

    Science.gov (United States)

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

    2016-08-01

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

  8. L-Lactate Protects Skin Fibroblasts against Aging-Associated Mitochondrial Dysfunction via Mitohormesis

    Directory of Open Access Journals (Sweden)

    Jaroslav Zelenka

    2015-01-01

    Full Text Available A moderate elevation of reactive oxygen species (ROS production and a mild inhibition of mitochondrial respiratory chain have been associated with a health promotion and a lifespan extension in several animal models of aging. Here, we tested whether this phenomenon called mitohormesis could be mediated by L-lactate. The treatment with 5 mM L-lactate significantly increased H2O2 production and slightly inhibited the respiration in cultured skin fibroblasts and in isolated mitochondria. The L-lactate exposure was associated with oxidation of intracellular glutathione, phosphorylation of 5′AMP-activated protein kinase (AMPK, and induction of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α transcription. A replicative aging of fibroblasts (L0 with a constant (LC, or intermittent 5 mM L-lactate (LI in media showed that the high-passage LI fibroblasts have higher respiration, lower H2O2 release, and lower secretion of L-lactate compared to L0 and LC. This protection against mitochondrial dysfunction in LI cells was associated with lower activity of mechanistic target of rapamycin complex 1 (mTORC1, less signs of cellular senescence, and increased autophagy compared to L0 and LC. In conclusion, we demonstrated that intermittent but not constant exposure to L-lactate triggers mitohormesis, prevents aging-associated mitochondrial dysfunction, and improves other markers of aging.

  9. Testosterone Protects Mitochondrial Function and Regulates Neuroglobin Expression in Astrocytic Cells Exposed to Glucose Deprivation

    Science.gov (United States)

    Toro-Urrego, Nicolas; Garcia-Segura, Luis M.; Echeverria, Valentina; Barreto, George E.

    2016-01-01

    Testosterone is a hormone that has been shown to confer neuroprotection from different insults affecting the central nervous system (CNS). Testosterone induces this protection by different mechanisms that include the activation of anti-apoptotic pathways that are directly implicated in neuronal survival. However, little attention has been devoted to its actions on glial cells. In the present study, we have assessed whether testosterone exerts protection in a human astrocyte cell model, the T98G cells. Our results indicate that testosterone improves cell survival and mitochondrial membrane potential and reduces nuclear fragmentation and reactive oxygen species (ROS) generation. These effects were accompanied by a positive regulation of neuroglobin, an oxygen-binding and sensor protein, which may serve as a regulator of ROS and nitrogen reactive species (NOS), and these protective effects of testosterone may be at least in part mediated by estradiol and DHT. In conclusion, these findings suggest that astroglia may mediate some of the protective actions of testosterone in the brain upon pathological conditions. PMID:27445795

  10. Reactive Oxygen Species-Mediated Control of Mitochondrial Biogenesis

    Directory of Open Access Journals (Sweden)

    Edgar D. Yoboue

    2012-01-01

    Full Text Available Mitochondrial biogenesis is a complex process. It necessitates the contribution of both the nuclear and the mitochondrial genomes and therefore crosstalk between the nucleus and mitochondria. It is now well established that cellular mitochondrial content can vary according to a number of stimuli and physiological states in eukaryotes. The knowledge of the actors and signals regulating the mitochondrial biogenesis is thus of high importance. The cellular redox state has been considered for a long time as a key element in the regulation of various processes. In this paper, we report the involvement of the oxidative stress in the regulation of some actors of mitochondrial biogenesis.

  11. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Juan P de Macêdo

    2015-05-01

    Full Text Available Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug

  12. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS mediated cardiomyocyte hypertrophy

    NARCIS (Netherlands)

    Tigchelaar, Wardit; Yu, Hongjuan; De Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Sillje, Herman H W

    2015-01-01

    Recently, a genetic variant in the mitochondrial exo/endo nuclease EXOG, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and

  13. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS mediated cardiomyocyte hypertrophy

    NARCIS (Netherlands)

    Tigchelaar, Wardit; Yu, Hongjuan; De Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Sillje, Herman H W

    2015-01-01

    Recently, a genetic variant in the mitochondrial exo/endo nuclease EXOG, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrop

  14. RNAi-mediated plant protection against aphids.

    Science.gov (United States)

    Yu, Xiu-Dao; Liu, Zong-Cai; Huang, Si-Liang; Chen, Zhi-Qin; Sun, Yong-Wei; Duan, Peng-Fei; Ma, You-Zhi; Xia, Lan-Qin

    2016-06-01

    Aphids (Aphididae) are major agricultural pests that cause significant yield losses of crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring harmful plant viruses. Expression of double-stranded RNA (dsRNA) directed against suitable insect target genes in transgenic plants has been shown to give protection against pests through plant-mediated RNA interference (RNAi). Thus, as a potential alternative and effective strategy for insect pest management in agricultural practice, plant-mediated RNAi for aphid control has received close attention in recent years. In this review, the mechanism of RNAi in insects and the so far explored effective RNAi target genes in aphids, their potential applications in the development of transgenic plants for aphid control and the major challenges in this regard are reviewed, and the future prospects of using plant-mediated RNAi for aphid control are discussed. This review is intended to be a helpful insight into the generation of aphid-resistant plants through plant-mediated RNAi strategy. © 2016 Society of Chemical Industry.

  15. Mitochondrial endonuclease G mediates breakdown of paternal mitochondria upon fertilization.

    Science.gov (United States)

    Zhou, Qinghua; Li, Haimin; Li, Hanzeng; Nakagawa, Akihisa; Lin, Jason L J; Lee, Eui-Seung; Harry, Brian L; Skeen-Gaar, Riley Robert; Suehiro, Yuji; William, Donna; Mitani, Shohei; Yuan, Hanna S; Kang, Byung-Ho; Xue, Ding

    2016-07-22

    Mitochondria are inherited maternally in most animals, but the mechanisms of selective paternal mitochondrial elimination (PME) are unknown. While examining fertilization in Caenorhabditis elegans, we observed that paternal mitochondria rapidly lose their inner membrane integrity. CPS-6, a mitochondrial endonuclease G, serves as a paternal mitochondrial factor that is critical for PME. We found that CPS-6 relocates from the intermembrane space of paternal mitochondria to the matrix after fertilization to degrade mitochondrial DNA. It acts with maternal autophagy and proteasome machineries to promote PME. Loss of cps-6 delays breakdown of mitochondrial inner membranes, autophagosome enclosure of paternal mitochondria, and PME. Delayed removal of paternal mitochondria causes increased embryonic lethality, demonstrating that PME is important for normal animal development. Thus, CPS-6 functions as a paternal mitochondrial degradation factor during animal development.

  16. IL-6-deficient Mice Are Susceptible to Ethanol-induced Hepatic Steatosis: IL-6 Protects against Ethanol-induced Oxidative Stress and Mitochondrial Permeability Transition in the Liver

    Institute of Scientific and Technical Information of China (English)

    Osama El-Assal; Feng Hong; Won-Ho Kim; Svetlana Radaeva; Bin Gao

    2004-01-01

    Interleukin-6 (IL-6)-deficient mice are prone to ethanol-induced apoptosis and steatosis in the liver; however, the underlying mechanism is not fully understood. Mitochondrial dysfunction caused by oxidative stress is an early event that plays an important role in the pathogenesis of alcoholic liver disease. Therefore, we hypothesize that the protective role of IL-6 in ethanol-induced liver injury is mediated via suppression of ethanol-induced oxidative stress and mitochondrial dysfunction. To test this hypothesis, we examined the effects of IL-6 on ethanol-induced oxidative stress, mitochondrial injury, and energy depletion in the livers of IL-6 (-/-) mice and hepatocytes from ethanol-fed rats. Ethanol consumption leads to stronger induction of malondialdehyde (MDA) in IL-6 (-/-) mice compared to wild-type control mice, which can be corrected by administration of IL-6. In vitro,IL-6 treatment prevents ethanol-mediated induction of reactive oxygen species (ROS), MDA, mitochondrial permeability transition (MPT), and ethanol-mediated depletion of adenosine triphosphate (ATP) in hepatocytes from ethanol-fed rats. Administration of IL-6 in vivo also reverses ethanol-induced MDA and ATP depletion in hepatocytes. Finally, IL-6 treatment induces metallothionein protein expression, but not superoxide dismutase and glutathione peroxidase in cultured hepatocytes. In conclusion, IL-6 protects against ethanol-induced oxidative stress and mitochondrial dysfunction in hepatocytes via induction of metallothionein protein expression, which may account for the protective role of IL-6 in alcoholic liver disease.

  17. Mitochondrial aldehyde dehydrogenase (ALDH2 protects against streptozotocin-induced diabetic cardiomyopathy: role of GSK3β and mitochondrial function

    Directory of Open Access Journals (Sweden)

    Zhang Yingmei

    2012-04-01

    Full Text Available Abstract Background Mitochondrial aldehyde dehydrogenase (ALDH2 displays some promise in the protection against cardiovascular diseases although its role in diabetes has not been elucidated. Methods This study was designed to evaluate the impact of ALDH2 on streptozotocin-induced diabetic cardiomyopathy. Friendly virus B(FVB and ALDH2 transgenic mice were treated with streptozotocin (intraperitoneal injection of 200 mg/kg to induce diabetes. Results Echocardiographic evaluation revealed reduced fractional shortening, increased end-systolic and -diastolic diameter, and decreased wall thickness in streptozotocin-treated FVB mice. Streptozotocin led to a reduced respiratory exchange ratio; myocardial apoptosis and mitochondrial damage; cardiomyocyte contractile and intracellular Ca2+ defects, including depressed peak shortening and maximal velocity of shortening and relengthening; prolonged duration of shortening and relengthening; and dampened intracellular Ca2+ rise and clearance. Western blot analysis revealed disrupted phosphorylation of Akt, glycogen synthase kinase-3β and Foxo3a (but not mammalian target of rapamycin, elevated PTEN phosphorylation and downregulated expression of mitochondrial proteins, peroxisome proliferator-activated receptor γ coactivator 1α and UCP-2. Intriguingly, ALDH2 attenuated or ablated streptozotocin-induced echocardiographic, mitochondrial, apoptotic and myocardial contractile and intracellular Ca2+ anomalies as well as changes in the phosphorylation of Akt, glycogen synthase kinase-3β, Foxo3a and phosphatase and tensin homologue on chromosome ten, despite persistent hyperglycemia and a low respiratory exchange ratio. In vitro data revealed that the ALDH2 activator Alda-1 and glycogen synthase kinase-3β inhibition protected against high glucose-induced mitochondrial and mechanical anomalies, the effect of which was cancelled by mitochondrial uncoupling. Conclusions In summary, our data revealed that ALDH2

  18. Lithium-mediated protection against ethanol neurotoxicity

    Directory of Open Access Journals (Sweden)

    Jia Luo

    2010-06-01

    Full Text Available Lithium has long been used as a mood stabilizer in the treatment of manic-depressive (bipolar disorder. Recent studies suggest that lithium has neuroprotective properties and may be useful in the treatment of acute brain injuries such as ischemia and chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and amyotrophic lateral sclerosis. One of the most important neuroprotective properties of lithium is its anti-apoptotic action. Ethanol is a neuroteratogen and fetal alcohol spectrum disorders (FASD are caused by maternal ethanol exposure during pregnancy. FASD is the leading cause of mental retardation. Ethanol exposure causes neuroapoptosis in the developing brain. Ethanol-induced loss of neurons in the central nervous system underlies many of the behavioral deficits observed in FASD. Excessive alcohol consumption is also associated with Wernicke–Korsakoff syndrome and neurodegeneration in the adult brain. Recent in vivo and in vitro studies indicate that lithium is able to ameliorate ethanol-induced neuroapoptosis. Lithium is an inhibitor of glycogen synthase kinase 3 (GSK3 which has recently been identified as a mediator of ethanol neurotoxicity. Lithium’s neuroprotection may be mediated by its inhibition of GSK3. In addition, lithium also affects many other signaling proteins and pathways that regulate neuronal survival and differentiation. This review discusses the recent evidence of lithium-mediated protection against ethanol neurotoxicity and potential underlying mechanisms.

  19. The Armc10/SVH gene: genome context, regulation of mitochondrial dynamics and protection against Aβ-induced mitochondrial fragmentation

    Science.gov (United States)

    Serrat, R; Mirra, S; Figueiro-Silva, J; Navas-Pérez, E; Quevedo, M; López-Doménech, G; Podlesniy, P; Ulloa, F; Garcia-Fernàndez, J; Trullas, R; Soriano, E

    2014-01-01

    Mitochondrial function and dynamics are essential for neurotransmission, neural function and neuronal viability. Recently, we showed that the eutherian-specific Armcx gene cluster (Armcx1–6 genes), located in the X chromosome, encodes for a new family of proteins that localise to mitochondria, regulating mitochondrial trafficking. The Armcx gene cluster evolved by retrotransposition of the Armc10 gene mRNA, which is present in all vertebrates and is considered to be the ancestor gene. Here we investigate the genomic organisation, mitochondrial functions and putative neuroprotective role of the Armc10 ancestor gene. The genomic context of the Armc10 locus shows considerable syntenic conservation among vertebrates, and sequence comparisons and CHIP-data suggest the presence of at least three conserved enhancers. We also show that the Armc10 protein localises to mitochondria and that it is highly expressed in the brain. Furthermore, we show that Armc10 levels regulate mitochondrial trafficking in neurons, but not mitochondrial aggregation, by controlling the number of moving mitochondria. We further demonstrate that the Armc10 protein interacts with the KIF5/Miro1-2/Trak2 trafficking complex. Finally, we show that overexpression of Armc10 in neurons prevents Aβ-induced mitochondrial fission and neuronal death. Our data suggest both conserved and differential roles of the Armc10/Armcx gene family in regulating mitochondrial dynamics in neurons, and underscore a protective effect of the Armc10 gene against Aβ-induced toxicity. Overall, our findings support a further degree of regulation of mitochondrial dynamics in the brain of more evolved mammals. PMID:24722288

  20. Adaptive aneuploidy protects against thiol peroxidase deficiency by increasing respiration via key mitochondrial proteins.

    Science.gov (United States)

    Kaya, Alaattin; Gerashchenko, Maxim V; Seim, Inge; Labarre, Jean; Toledano, Michel B; Gladyshev, Vadim N

    2015-08-25

    Aerobic respiration is a fundamental energy-generating process; however, there is cost associated with living in an oxygen-rich environment, because partially reduced oxygen species can damage cellular components. Organisms evolved enzymes that alleviate this damage and protect the intracellular milieu, most notably thiol peroxidases, which are abundant and conserved enzymes that mediate hydrogen peroxide signaling and act as the first line of defense against oxidants in nearly all living organisms. Deletion of all eight thiol peroxidase genes in yeast (∆8 strain) is not lethal, but results in slow growth and a high mutation rate. Here we characterized mechanisms that allow yeast cells to survive under conditions of thiol peroxidase deficiency. Two independent ∆8 strains increased mitochondrial content, altered mitochondrial distribution, and became dependent on respiration for growth but they were not hypersensitive to H2O2. In addition, both strains independently acquired a second copy of chromosome XI and increased expression of genes encoded by it. Survival of ∆8 cells was dependent on mitochondrial cytochrome-c peroxidase (CCP1) and UTH1, present on chromosome XI. Coexpression of these genes in ∆8 cells led to the elimination of the extra copy of chromosome XI and improved cell growth, whereas deletion of either gene was lethal. Thus, thiol peroxidase deficiency requires dosage compensation of CCP1 and UTH1 via chromosome XI aneuploidy, wherein these proteins support hydroperoxide removal with the reducing equivalents generated by the electron transport chain. To our knowledge, this is the first evidence of adaptive aneuploidy counteracting oxidative stress.

  1. Polyethylenimine-mediated impairment of mitochondrial membrane potential, respiration and membrane integrity

    DEFF Research Database (Denmark)

    Larsen, Anna Karina; Malinska, Dominika; Koszela-Piotrowska, Izabela

    2012-01-01

    The 25 kDa branched polyethylenimine (PEI) is a highly efficient synthetic polycation used in transfection protocols, but also triggers mitochondrial-mediated apoptotic cell death processes where the mechanistic issues are poorly understood. We now demonstrate that PEI in a concentration- and time......-dependent manner can affect functions (membrane potential, swelling and respiration) and ultrastructural integrity of freshly isolated rat liver mitochondria. The threshold concentration for detection of PEI-mediated impairment of rat liver mitochondrial functions is 3 µg/mL, however, lower PEI levels still exert...... some effects on mitochondrial morphology and respiration, and these may be related to the inherent membrane perturbing properties of this polycation. The PEI-mediated mitochondrial swelling phase is biphasic, with a fast decaying initial period (most prominent from 4 µg/mL PEI) followed by a slower...

  2. Mitochondrial protein acetylation mediates nutrient sensing of mitochondrial protein synthesis and mitonuclear protein balance.

    Science.gov (United States)

    Di Domenico, Antonella; Hofer, Annette; Tundo, Federica; Wenz, Tina

    2014-11-01

    Changes in nutrient supply require global metabolic reprogramming to optimize the utilization of the nutrients. Mitochondria as a central component of the cellular metabolism play a key role in this adaptive process. Since mitochondria harbor their own genome, which encodes essential enzymes, mitochondrial protein synthesis is a determinant of metabolic adaptation. While regulation of cytoplasmic protein synthesis in response to metabolic challenges has been studied in great detail, mechanisms which adapt mitochondrial translation in response to metabolic challenges remain elusive. Our results suggest that the mitochondrial acetylation status controlled by Sirt3 and its proposed opponent GCN5L1 is an important regulator of the metabolic adaptation of mitochondrial translation. Moreover, both proteins modulate regulators of cytoplasmic protein synthesis as well as the mitonuclear protein balance making Sirt3 and GCN5L1 key players in synchronizing mitochondrial and cytoplasmic translation. Our results thereby highlight regulation of mitochondrial translation as a novel component in the cellular nutrient sensing scheme and identify mitochondrial acetylation as a new regulatory principle for the metabolic competence of mitochondrial protein synthesis.

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

    Science.gov (United States)

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

    2012-01-01

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

  4. Inhibition of Drp1 mitochondrial translocation provides neural protection in dopaminergic system in a Parkinson’s disease model induced by MPTP

    Science.gov (United States)

    Filichia, Emily; Hoffer, Barry; Qi, Xin; Luo, Yu

    2016-01-01

    Accumulating evidence suggest mitochondria-mediated pathways play an important role in dopaminergic neuronal cell death in Parkinson’s disease (PD). Drp1, a key regulator of mitochondrial fission, has been shown to be activated and translocated to mitochondria under stress, leading to excessive mitochondria fission and dopaminergic neuronal death in vitro. However, whether Drp1 inhibition can lead to long term stable preservation of dopaminergic neurons in PD-related mouse models remains unknown. In this study, using a classical MPTP animal PD model, we showed for the first time Drp1 activation and mitochondrial translocation in vivo after MPTP administration. Inhibition of Drp1 activation by a selective peptide inhibitor P110, blocked MPTP-induced Drp1 mitochondrial translocation and attenuated dopaminergic neuronal loss, dopaminergic nerve terminal damage and behavioral deficits caused by MPTP. MPTP-induced microglial activation and astrogliosis were not affected by P110 treatment. Instead, inhibition of Drp1 mitochondrial translocation diminished MPTP-induced p53, BAX and PUMA mitochondrial translocation. This study demonstrates that inhibition of Drp1 hyperactivation by a Drp1 peptide inhibitor P110 is neuroprotective in a MPTP animal model. Our data also suggest that the protective effects of P110 treatment might be mediated by inhibiting the p53 mediated apoptotic pathways in neurons through inhibition of Drp1-dependent p53 mitochondrial translocation. PMID:27619562

  5. IL-6-deficient Mice Are Susceptible to Ethanol-induced Hepatic Steatosis: IL-6 Protects against Ethanol-induced Oxidative Stress and Mitochondrial Permeability Transition in the Liver

    Institute of Scientific and Technical Information of China (English)

    OsamaEl-Assal; FengHong; Won-HoKim; SvetlanaRadaeva; BinGao

    2004-01-01

    Interleukin-6 (IL-6)-deficient mice are prone to ethanol-induced apoptosis and steatosis in the liver; however,the underlying mechanism is not fully understood. Mitochondrial dysfunction caused by oxidative stress is an early event that plays an important role in the pathogenesis of alcoholic liver disease. Therefore, we hypothesize that the protective role of IL-6 in ethanol-induced liver injury is mediated via suppression of ethanol-induced oxidative stress and mitochondrial dysfunction. To test this hypothesis, we examined the effects of IL-6 on ethanol-induced oxidative stress, mitochondrial injury, and energy depletion in the livers of IL-6 (-/-) mice and hepatocytes from ethanol-fed rats. Ethanol consumption leads to stronger induction of malondialdehyde (MDA) in IL-6 (-/-) mice compared to wild-type control mice, which can be corrected by administration of IL-6. In vitro,IL-6 treatment prevents ethanol-mediated induction of reactive oxygen species (ROS), MDA, mitochondrial permeability transition (MPT), and ethanol-mediated depletion of adenosine triphosphate (ATP) in hepatocytes from ethanol-fed rats. Administration of IL-6 in vivo also reverses ethanol-induced MDA and ATP depletion in hepatocytes. Finally, IL-6 treatment induces metallothionein protein expression, but not superoxide dismutase and glutathione peroxidase in cultured hepatocytes. In conclusion, IL-6 protects against ethanol-induced oxidative stress and mitochondrial dysfunction in hepatocytes v/a induction of metallothionein protein expression, which mav account for the nrotective role of IL-6 in alcoholic liver disease.

  6. GATA-4 protects against hypoxia-induced cardiomyocyte injury: effects on mitochondrial membrane potential.

    Science.gov (United States)

    Li, Hong-Xia; Zhou, Ya-Feng; Zhao, Xin; Jiang, Bin; Yang, Xiang-Jun

    2014-08-01

    Our previous studies have suggested that GATA-4 increases the differentiation of bone-marrow-derived mesenchymal stem cells (MSCs) into cardiac phenotypes. This study further investigated whether GATA-4 enhances MSC-mediated cardioprotection following hypoxia. MSCs were harvested from rat bone marrow and transduced with GATA-4 (MSC(GATA-4)). To mimic ischemic injury, cultured cardiomyocytes (CMs) isolated from neonatal rat ventricles were exposed to hypoxia or were pretreated with concentrated conditioned medium (CdM) from MSC(GATA-4) or transduced control MSC (MSC(Null)) for 16 h before exposure to hypoxic culture conditions (low glucose and low oxygen). Myocyte damage was estimated by annexin-V-PE and TUNEL technique and by lactate dehydrogenase (LDH) release. Cell survival was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium (MTT) uptake. Mitochondrial membrane potential was determined using confocal microscopy. ELISA studies indicated that insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) were significantly increased in MSC(GATA-4) compared with MSC(Null). Hypoxia-induced apoptosis/cell death was significantly reduced when CMs were co-cultured with MSC(GATA-4) in a dual-chamber system. Cell protection mediated by MSC(GATA-4) was mimicked by treating CMs with CdM from MSC(GATA-4) and abrogated with IGF-1- and VEGF-neutralizing antibodies. MSC(GATA-4) protects CMs under hypoxic conditions. The release of IGF-1 and VEGF from MSC(GATA-4) is likely to be responsible for protection of CMs.

  7. Protective role of mitochondrial K-ATP channel and mitochondrial membrane transport pore in rat kidney ischemic postconditioning

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-liang; ZHAO Yan-li; LIU Xiao-ming; CHEN Jing; ZHANG Dong

    2011-01-01

    Background Previous studies suggested that mechanical intervention during early reperfusion, or ischemia postconditioning (Ipo), could protect kidneys against renal ischemia reperfusion injury (RIRI). However, the mechanisms responsible for this protection remain unclear. This study therefore investigated the protection afforded by Ipo in rat kidneys in vivo, and the roles of mitochondrial KATP channels (mitOKATP) and mitochondrial permeability transition pores (MPTPs), by inhibiting mitOKATP with 5-hydroxydecanoate (5-HD), and by directly detecting open MPTPs using calcein-AM and CoCl2.Methods Thirty-five male Sprague-Dawley rats were randomly assigned to sham-operation (S), ischemia-reperfusion (I/R),Ipo, ischemia reperfusion with 5-HD (I/R+5-HD), or Ipo with 5-HD (Ipo +5-HD) groups. Rats in each group were sacrificed after 6 hours of reperfusion by heart exsanguination or cervical dislocation under anesthesia. RIRI was assessed by determination of creatinine and blood urea nitrogen (BUN), and by examination of histologic sections. The roles of mitoKATP and MPTP were investigated by analyzing fluorescence intensities of mitochondria, mitochondrial membrane potential,intracellular reactive oxygen species (ROS) and intracellular calcium, using appropriate fluorescent markers. The relationship between apoptosis and RIRI was assessed by determining the apoptotic index (Al) of kidney tubular epithelial cells.Results The RIRI model was shown to be successful. Significantly higher levels of creatinine and BUN, and abnormal pathology of histologic sections, were observed in group I/R, compared with group S. 5-HD eliminated the renoprotective effects of Ipo. Mitochondrial and mitochondrial membrane potential fluorescence intensities increased, and intracellular calcium, ROS fluorescence intensities and AI decreased in group Ipo, compared with group I/R. However, mitochondrial and mitochondrial membrane potential fluorescence intensities decreased, and intracellular

  8. Peptide-mediated delivery of donor mitochondria improves mitochondrial function and cell viability in human cybrid cells with the MELAS A3243G mutation.

    Science.gov (United States)

    Chang, Jui-Chih; Hoel, Fredrik; Liu, Ko-Hung; Wei, Yau-Huei; Cheng, Fu-Chou; Kuo, Shou-Jen; Tronstad, Karl Johan; Liu, Chin-San

    2017-09-06

    The cell penetrating peptide, Pep-1, has been shown to facilitate cellular uptake of foreign mitochondria but further research is required to evaluate the use of Pep-1-mediated mitochondrial delivery (PMD) in treating mitochondrial defects. Presently, we sought to determine whether mitochondrial transplantation rescue mitochondrial function in a cybrid cell model of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) disease. Following PMD, recipient cells had internalized donor mitochondria after 1 h, and expressed higher levels of normal mitochondrial DNA, particularly at the end of the treatment and 11 days later. After 4 days, mitochondrial respiratory function had recovered and biogenesis was evident in the Pep-1 and PMD groups, compared to the untreated MELAS group. However, only PMD was able to reverse the fusion-to-fission ratio of mitochondrial morphology, and mitochondria shaping proteins resembled the normal pattern seen in the control group. Cell survival following hydrogen peroxide-induced oxidative stress was also improved in the PMD group. Finally, we observed that PMD partially normalized cytokine expression, including that of interleukin (IL)-7, granulocyte macrophage-colony-stimulating factor (GM-CSF), and vascular endothelial growth factor (VEGF), in the MELAS cells. Presently, our data further confirm the protective effects of PMD as well in MELAS disease.

  9. Protective effects of l-carnitine and piracetam against mitochondrial permeability transition and PC3 cell necrosis induced by simvastatin.

    Science.gov (United States)

    Costa, Rute A P; Fernandes, Mariana P; de Souza-Pinto, Nadja C; Vercesi, Aníbal E

    2013-02-15

    Mitochondrial oxidative stress followed by membrane permeability transition (MPT) has been considered as a possible mechanism for statins cytotoxicity. Statins use has been associated with reduced risk of cancer incidence, especially prostate cancer. Here we investigated the pathways leading to simvastatin-induced prostate cancer cell death as well as the mechanisms of cell death protection by l-carnitine or piracetam. These compounds are known to prevent and/or protect against cell death mediated by oxidative mitochondrial damage induced by a variety of conditions, either in vivo or in vitro. The results provide evidence that simvastatin induced MPT and cell necrosis were sensitive to either l-carnitine or piracetam in a dose-dependent fashion and mediated by additive mechanisms. When combined, l-carnitine and piracetam acted at concentrations significantly lower than they act individually. These results shed new light into both the cytotoxic mechanisms of statins and the mechanisms underlying the protection against MPT and cell death by the compounds l-carnitine and piracetam. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Protective role of PGC-1α in diabetic nephropathy is associated with the inhibition of ROS through mitochondrial dynamic remodeling.

    Directory of Open Access Journals (Sweden)

    Kaifeng Guo

    Full Text Available The overproduction of mitochondrial reactive oxygen species (ROS plays a key role in the pathogenesis of diabetic nephropathy (DN. However, the underlying molecular mechanism remains unclear. Our aim was to investigate the role of PGC-1α in the pathogenesis of DN. Rat glomerular mesangial cells (RMCs were incubated in normal or high glucose medium with or without the PGC-1α-overexpressing plasmid (pcDNA3-PGC-1α for 48 h. In the diabetic rats, decreased PGC-1α expression was associated with increased mitochondrial ROS generation in the renal cortex, increased proteinuria, glomerular hypertrophy, and higher glomerular 8-OHdG (a biomarker for oxidative stress. In vitro, hyperglycemia induced the downregulation of PGC-1α, which led to increased DRP1 expression, increased mitochondrial fragmentation and damaged network structure. This was associated with an increase in ROS generation and mesangial cell hypertrophy. These pathological changes were reversed in vitro by the transfection of pcDNA3-PGC-1α. These data suggest that PGC-1α may protect DN via the inhibition of DRP1-mediated mitochondrial dynamic remodeling and ROS production. These findings may assist the development of novel therapeutic strategies for patients with DN.

  11. Protective Role of PGC-1α in Diabetic Nephropathy Is Associated with the Inhibition of ROS through Mitochondrial Dynamic Remodeling

    Science.gov (United States)

    Huang, Yan; Wu, Mian; Zhang, Lei; Yu, Haoyong; Zhang, Mingliang; Bao, Yuqian; He, John Cijiang; Chen, Haibing; Jia, Weiping

    2015-01-01

    The overproduction of mitochondrial reactive oxygen species (ROS) plays a key role in the pathogenesis of diabetic nephropathy (DN). However, the underlying molecular mechanism remains unclear. Our aim was to investigate the role of PGC-1α in the pathogenesis of DN. Rat glomerular mesangial cells (RMCs) were incubated in normal or high glucose medium with or without the PGC-1α-overexpressing plasmid (pcDNA3-PGC-1α) for 48 h. In the diabetic rats, decreased PGC-1α expression was associated with increased mitochondrial ROS generation in the renal cortex, increased proteinuria, glomerular hypertrophy, and higher glomerular 8-OHdG (a biomarker for oxidative stress). In vitro, hyperglycemia induced the downregulation of PGC-1α, which led to increased DRP1 expression, increased mitochondrial fragmentation and damaged network structure. This was associated with an increase in ROS generation and mesangial cell hypertrophy. These pathological changes were reversed in vitro by the transfection of pcDNA3-PGC-1α. These data suggest that PGC-1α may protect DN via the inhibition of DRP1-mediated mitochondrial dynamic remodeling and ROS production. These findings may assist the development of novel therapeutic strategies for patients with DN. PMID:25853493

  12. Mitochondrial aldehyde dehydrogenase 2 protects gastric mucosa cells against DNA damage caused by oxidative stress.

    Science.gov (United States)

    Duan, Yantao; Gao, Yaohui; Zhang, Jun; Chen, Yinan; Jiang, Yannan; Ji, Jun; Zhang, Jianian; Chen, Xuehua; Yang, Qiumeng; Su, Liping; Zhang, Jun; Liu, Bingya; Zhu, Zhenggang; Wang, Lishun; Yu, Yingyan

    2016-04-01

    Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a member of the aldehyde dehydrogenase superfamily and is involved with the metabolic processing of aldehydes. ALDH2 plays a cytoprotective role by removing aldehydes produced during normal metabolism. We examined the cytoprotective role of ALDH2 specifically in gastric mucosa cells. Overexpression of ALDH2 increased the viability of gastric mucosa cells treated with H2O2, while knockdown of ALDH2 had an opposite effect. Moreover, overexpression of ALDH2 protected gastric mucosa cells against oxidative stress-induced apoptosis as determined by flow cytometry, Hoechst 33342, and TUNEL assays. Consistently, ALDH2 knockdown had an opposite effect. Additionally, DNA damage was ameliorated in ALDH2-overexpressing gastric mucosa cells treated with H2O2. We further identified that this cytoprotective role of ALDH2 was mediated by metabolism of 4-hydroxynonenal (4-HNE). Consistently, 4-HNE mimicked the oxidative stress induced by H2O2 in gastric mucosa cells. Treatment with 4-HNE increased levels of DNA damage in ALDH2-knockdown GES-1 cells, while overexpression of ALDH2 decreased 4-HNE-induced DNA damage. These findings suggest that ALDH2 can protect gastric mucosa cells against DNA damage caused by oxidative stress by reducing levels of 4-HNE.

  13. Rebamipide suppresses diclofenac-induced intestinal permeability via mitochondrial protection in mice.

    Science.gov (United States)

    Diao, Lei; Mei, Qiao; Xu, Jian-Ming; Liu, Xiao-Chang; Hu, Jing; Jin, Juan; Yao, Qiang; Chen, Mo-Li

    2012-03-14

    To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.

  14. Rebamipide suppresses diclofenac-induced intestinal permeability via mitochondrial protection in mice

    Institute of Scientific and Technical Information of China (English)

    Lei Diao; Qiao Mei; Jian-Ming Xu; Xiao-Chang Liu; Jing Hu; Juan Jin; Qiang Yao

    2012-01-01

    AIM:To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice.METHODS:Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally.A control group received the vehicle by gavage.Rebamipide (100 mg/kg,200 mg/kg,400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration.Intestinal permeability was evaluated by Evans blue and the FITC-dextran method.The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM).Mitochondrial function including mitochondrial swelling,mitochondrial membrane potential,mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels,succinate dehydrogenase (SDH) and ATPase activities were measured.Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity.RESULTS:Compared with the control group,intestinal permeability was significantly increased in the diclofenac group,which was accompanied by broken tight junctions,and significant increases in MDA content and MPO activity.Rebamipide significantly reduced intestinal permeability,improved inter-cellular tight junctions,and was associated with decreases in intestinal MDA content and MPO activity.At the mitochondrial level,rebamipide increased SDH and ATPase activities,NADH level and decreased mitochondrial swelling.CONCLUSION:Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide,which partially contributed to the protection of mitochondrial function.

  15. Catecholamine-induced cardiac mitochondrial dysfunction and mPTP opening: protective effect of curcumin.

    Science.gov (United States)

    Izem-Meziane, Malika; Djerdjouri, Bahia; Rimbaud, Stephanie; Caffin, Fanny; Fortin, Dominique; Garnier, Anne; Veksler, Vladimir; Joubert, Frederic; Ventura-Clapier, Renee

    2012-02-01

    The present study was designed to characterize the mitochondrial dysfunction induced by catecholamines and to investigate whether curcumin, a natural antioxidant, induces cardioprotective effects against catecholamine-induced cardiotoxicity by preserving mitochondrial function. Because mitochondria play a central role in ischemia and oxidative stress, we hypothesized that mitochondrial dysfunction is involved in catecholamine toxicity and in the potential protective effects of curcumin. Male Wistar rats received subcutaneous injection of 150 mg·kg(-1)·day(-1) isoprenaline (ISO) for two consecutive days with or without pretreatment with 60 mg·kg(-1)·day(-1) curcumin. Twenty four hours after, cardiac tissues were examined for apoptosis and oxidative stress. Expression of proteins involved in mitochondrial biogenesis and function were measured by real-time RT-PCR. Isolated mitochondria and permeabilized cardiac fibers were used for swelling and mitochondrial function experiments, respectively. Mitochondrial morphology and permeability transition pore (mPTP) opening were assessed by fluorescence in isolated cardiomyocytes. ISO treatment induced cell damage, oxidative stress, and apoptosis that were prevented by curcumin. Moreover, mitochondria seem to play an important role in these effects as respiration and mitochondrial swelling were increased following ISO treatment, these effects being again prevented by curcumin. Importantly, curcumin completely prevented the ISO-induced increase in mPTP calcium susceptibility in isolated cardiomyocytes without affecting mitochondrial biogenesis and mitochondrial network dynamic. The results unravel the importance of mitochondrial dysfunction in isoprenaline-induced cardiotoxicity as well as a new cardioprotective effect of curcumin through prevention of mitochondrial damage and mPTP opening.

  16. The mitochondrial calcium regulator cyclophilin D is an essential component of oestrogen-mediated neuroprotection in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Kim, Hyun Jeong; Magranè, Jordi; Starkov, Anatoly A; Manfredi, Giovanni

    2012-09-01

    Amyotrophic lateral sclerosis is a devastating neurodegenerative disorder that is more prevalent in males than in females. A similar gender difference has been reported in some strains of transgenic mouse models of familial amyotrophic lateral sclerosis harbouring the G93A mutation in CuZn superoxide dismutase. Mitochondrial damage caused by pathological alterations in Ca(2+) accumulation is frequently involved in neurodegenerative diseases, including CuZn superoxide dismutase-related amyotrophic lateral sclerosis, but its association with gender is not firmly established. In this study, we examined the effects of genetic ablation of cyclophilin D on gender differences in mice expressing G93A mutant CuZn superoxide dismutase. Cyclophilin D is a mitochondrial protein that promotes mitochondrial damage from accumulated Ca(2+). As anticipated, we found that cyclophilin D ablation markedly increased Ca(2+) retention in brain mitochondria of both males and females. Surprisingly, cyclophilin D ablation completely abolished the phenotypic advantage of G93A females, with no effect on disease in males. We also found that the 17β-oestradiol decreased Ca(2+) retention in brain mitochondria, and that cyclophilin D ablation abolished this effect. Furthermore, 17β-oestradiol protected G93A cortical neurons and spinal cord motor neurons against glutamate toxicity, but the protection was lost in neurons lacking cyclophilin D. Taken together, these results identify a novel mechanism of oestrogen-mediated neuroprotection in CuZn superoxide dismutase-related amyotrophic lateral sclerosis, whereby Ca(2+) overload and mitochondrial damage are prevented in a cyclophilin D-dependent manner. Such a protective mechanism may contribute to the lower incidence and later onset of amyotrophic lateral sclerosis, and perhaps other chronic neurodegenerative diseases, in females.

  17. Mitochondrial Protection by Exogenous Otx2 in Mouse Retinal Neurons

    Directory of Open Access Journals (Sweden)

    Hyoung-Tai Kim

    2015-11-01

    Full Text Available OTX2 (orthodenticle homeobox 2 haplodeficiency causes diverse defects in mammalian visual systems ranging from retinal dysfunction to anophthalmia. We find that the retinal dystrophy of Otx2+/GFP heterozygous knockin mice is mainly due to the loss of bipolar cells and consequent deficits in retinal activity. Among bipolar cell types, OFF-cone bipolar subsets, which lack autonomous Otx2 gene expression but receive Otx2 proteins from photoreceptors, degenerate most rapidly in Otx2+/GFP mouse retinas, suggesting a neuroprotective effect of the imported Otx2 protein. In support of this hypothesis, retinal dystrophy in Otx2+/GFP mice is prevented by intraocular injection of Otx2 protein, which localizes to the mitochondria of bipolar cells and facilitates ATP synthesis as a part of mitochondrial ATP synthase complex. Taken together, our findings demonstrate a mitochondrial function for Otx2 and suggest a potential therapeutic application of OTX2 protein delivery in human retinal dystrophy.

  18. Improving Mitochondrial Function Protects Bumblebees from Neonicotinoid Pesticides

    Science.gov (United States)

    Powner, Michael B.; Salt, Thomas E.; Hogg, Chris; Jeffery, Glen

    2016-01-01

    Global pollination is threatened by declining insect pollinator populations that may be linked to neonicotinoid pesticide use. Neonicotinoids over stimulate neurons and depolarize their mitochondria, producing immobility and death. However, mitochondrial function can be improved by near infrared light absorbed by cytochrome c oxidase in mitochondrial respiration. In flies, daily exposure to 670nm light throughout life increases average lifespan and aged mobility, and reduces systemic inflammation. Here we treat bumble bees with Imidacloprid a common neonicotinoid. This undermined ATP and rapidly induced immobility and reduced visual function and survival. Bees exposed to insecticide and daily to 670nm light showed corrected ATP levels and significantly improved mobility allowing them to feed. Physiological recordings from eyes revealed that light exposure corrected deficits induced by the pesticide. Overall, death rates in bees exposed to insecticide but also given 670nm light were indistinguishable from controls. When Imidacloprid and light exposure were withdrawn, survival was maintained. Bees and insects generally cannot see deep red light so it does not disturb their behaviour. Hence, we show that deep red light exposure that improves mitochondrial function, reverses the sensory and motor deficits induced by Imidacloprid. These results may have important implications as light delivery is economic and can be placed in hives/colonies. PMID:27846310

  19. Targeted overexpression of mitochondrial catalase protects against cancer chemotherapy-induced skeletal muscle dysfunction.

    Science.gov (United States)

    Gilliam, Laura A A; Lark, Daniel S; Reese, Lauren R; Torres, Maria J; Ryan, Terence E; Lin, Chien-Te; Cathey, Brook L; Neufer, P Darrell

    2016-08-01

    The loss of strength in combination with constant fatigue is a burden on cancer patients undergoing chemotherapy. Doxorubicin, a standard chemotherapy drug used in the clinic, causes skeletal muscle dysfunction and increases mitochondrial H2O2 We hypothesized that the combined effect of cancer and chemotherapy in an immunocompetent breast cancer mouse model (E0771) would compromise skeletal muscle mitochondrial respiratory function, leading to an increase in H2O2-emitting potential and impaired muscle function. Here, we demonstrate that cancer chemotherapy decreases mitochondrial respiratory capacity supported with complex I (pyruvate/glutamate/malate) and complex II (succinate) substrates. Mitochondrial H2O2-emitting potential was altered in skeletal muscle, and global protein oxidation was elevated with cancer chemotherapy. Muscle contractile function was impaired following exposure to cancer chemotherapy. Genetically engineering the overexpression of catalase in mitochondria of muscle attenuated mitochondrial H2O2 emission and protein oxidation, preserving mitochondrial and whole muscle function despite cancer chemotherapy. These findings suggest mitochondrial oxidants as a mediator of cancer chemotherapy-induced skeletal muscle dysfunction. Copyright © 2016 the American Physiological Society.

  20. Mitochondrial protection by low doses of insulin-like growth factor- Ⅰ in experimental cirrhosis

    Institute of Scientific and Technical Information of China (English)

    Raquel Pérez; María García-Fernández; Matías Díaz-Sánchez; Juan E Puche; Gloria Delgado; Marian Conchillo; Jordi Muntané; Inma Castilla-Cortázar

    2008-01-01

    AIM:To characterize the mitochondrial dysfunction in experimental cirrhosis and to study whether insulin-like growth factor- I (IGF-I) therapy (4 wk) is able to in-duce beneficial effects on damaged mitochondria leading to cellular protection.METHODS:Wistar rats were divided into three groups:Control group,untreated cirrhotic rats and cirrhotic rats treated with IGF-I treatment (2 μg/100 g bw/d).Mitochondrial function was analyzed by flow cytometry in isolated hepatic mitochondria,caspase 3 activation was assessed by Western blot and apoptosis by TUNEL in the three experimental groups.RESULTS:Untreated cirrhotic rats showed a mitochondrial dysfunction characterized by a significant reduction of mitochondrial membrane potential (in status 4 and 3);an increase of intramitochondrial reactive oxigen species (ROS) generation and a significant reduction of ATPase activity.IGF-Ⅰ therapy normalized mitochondrial function by increasing the membrane potential and ATPase activity and reducing the intramitochondrial free radical production.Activity of the electron transport complexes Ⅰ and Ⅲ was increased in both cirrhotic groups.In addition,untreated cirrhotic rats showed an increase of caspase 3 activation and apoptosis.IGF- Ⅰ therapy reduced the expression of the active peptide of caspase 3 and resulted in reduced apoptosis.CONCLUSION:These results show that IGF- Ⅰ exerts a mitochondrial protection in experimental cirrhosis leading to reduced apoptosis and increased ATP production.

  1. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Science.gov (United States)

    Xing, Shasha; Yang, Xiaoyan; Li, Wenjing; Bian, Fang; Wu, Dan; Chi, Jiangyang; Xu, Gao; Zhang, Yonghui; Jin, Si

    2014-01-01

    Salidroside (SAL) is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2-) induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs) with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙−) production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO) production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS), adenosine monophosphate-activated protein kinase (AMPK), and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB). SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α), and mitochondrial transcription factor A (TFAM) in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm) and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways. PMID:24868319

  2. Salidroside Stimulates Mitochondrial Biogenesis and Protects against H2O2-Induced Endothelial Dysfunction

    Directory of Open Access Journals (Sweden)

    Shasha Xing

    2014-01-01

    Full Text Available Salidroside (SAL is an active component of Rhodiola rosea with documented antioxidative properties. The purpose of this study is to explore the mechanism of the protective effect of SAL on hydrogen peroxide- (H2O2- induced endothelial dysfunction. Pretreatment of the human umbilical vein endothelial cells (HUVECs with SAL significantly reduced the cytotoxicity brought by H2O2. Functional studies on the rat aortas found that SAL rescued the endothelium-dependent relaxation and reduced superoxide anion (O2∙- production induced by H2O2. Meanwhile, SAL pretreatment inhibited H2O2-induced nitric oxide (NO production. The underlying mechanisms involve the inhibition of H2O2-induced activation of endothelial nitric oxide synthase (eNOS, adenosine monophosphate-activated protein kinase (AMPK, and Akt, as well as the redox sensitive transcription factor, NF-kappa B (NF-κB. SAL also increased mitochondrial mass and upregulated the mitochondrial biogenesis factors, peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1α, and mitochondrial transcription factor A (TFAM in the endothelial cells. H2O2-induced mitochondrial dysfunction, as demonstrated by reduced mitochondrial membrane potential (Δψm and ATP production, was rescued by SAL pretreatment. Taken together, these findings implicate that SAL could protect endothelium against H2O2-induced injury via promoting mitochondrial biogenesis and function, thus preventing the overactivation of oxidative stress-related downstream signaling pathways.

  3. Protection against Mitochondrial and Metal Toxicity Depends on Functional Lipid Binding Sites in ATP13A2

    Directory of Open Access Journals (Sweden)

    Shaun Martin

    2016-01-01

    Full Text Available The late endo-/lysosomal P-type ATPase ATP13A2 (PARK9 is implicated in Parkinson’s disease (PD and Kufor-Rakeb syndrome, early-onset atypical Parkinsonism. ATP13A2 interacts at the N-terminus with the signaling lipids phosphatidic acid (PA and phosphatidylinositol (3,5 bisphosphate (PI(3,5P2, which modulate ATP13A2 activity under cellular stress conditions. Here, we analyzed stable human SHSY5Y cell lines overexpressing wild-type (WT or ATP13A2 mutants in which three N-terminal lipid binding sites (LBS1–3 were mutated. We explored the regulatory role of LBS1–3 in the cellular protection by ATP13A2 against mitochondrial stress induced by rotenone and found that the LBS2-3 mutants displayed an abrogated protective effect. Moreover, in contrast to WT, the LBS2 and LBS3 mutants responded poorly to pharmacological inhibition of, respectively, PI(3,5P2 and PA formation. We further demonstrate that PA and PI(3,5P2 are also required for the ATP13A2-mediated protection against the toxic metals Mn2+, Zn2+, and Fe3+, suggesting a general lipid-dependent activation mechanism of ATP13A2 in various PD-related stress conditions. Our results indicate that the ATP13A2-mediated protection requires binding of PI(3,5P2 to LBS2 and PA to LBS3. Thus, targeting the N-terminal lipid binding sites of ATP13A2 might offer a therapeutic approach to reduce cellular toxicity of various PD insults including mitochondrial stress.

  4. Exercise-induced protection against reperfusion arrhythmia involves stabilization of mitochondrial energetics

    OpenAIRE

    Alleman, Rick J; Tsang, Alvin M.; Ryan, Terence E; Patteson, Daniel J.; McClung, Joseph M.; Spangenburg, Espen E.; Shaikh, Saame Raza; Neufer, P. Darrell; Brown, David A.

    2016-01-01

    While the cardiac benefits of exercise are clear, the underlying mechanism(s) are not completely understood. This is the first study to demonstrate, in intact hearts, isolated myocytes, and isolated mitochondria, that exercise confers an intrinsic protective phenotype by sustaining mitochondrial energetics and reducing reactive oxygen species in early reperfusion.

  5. The Mitochondrial Unfolded Protein Response Protects against Anoxia in Caenorhabditis elegans

    Science.gov (United States)

    Peña, Salvador; Sherman, Teresa; Brookes, Paul S.; Nehrke, Keith

    2016-01-01

    The mitochondrial unfolded protein response (UPRmt) is a surveillance pathway that defends proteostasis in the “powerhouse” of the cell. Activation of the UPRmt protects against stresses imposed by reactive oxygen species, respiratory chain deficits, and pathologic bacteria. Consistent with the UPRmt’s role in adaption, we found that either its pharmacological or genetic activation by ethidium bromide (EtBr) or RNAi of the mitochondrial AAA-protease spg-7 was sufficient to reduce death in an anoxia-based Caenorhabditis elegans model of ischemia-reperfusion injury. The UPRmt-specific transcription factor atfs-1 was necessary for protection and atfs-1 gain-of-function (gf) mutants were endogenously protected from both death and dysfunction. Neurons exhibited less axonal degeneration following non-lethal anoxia-reperfusion (A-R) when the UPRmt was pre-activated, and consistent with the concept of mitochondrial stress leading to cell non-autonomous (ie. “remote”) effects, we found that restricted activation of the UPRmt in neurons decreased A-R death. However, expression of the atfs-1(gf) mutant in neurons, which resulted in a robust activation of a neuronal UPRmt, did not upregulate the UPRmt in distal tissues, nor did it protect the worms from A-R toxicity. These findings suggest that remote signaling requires additional component(s) acting downstream of de facto mitochondrial stress. PMID:27459203

  6. Permeability transition pore-mediated mitochondrial superoxide flashes regulate cortical neural progenitor differentiation.

    Science.gov (United States)

    Hou, Yan; Mattson, Mark P; Cheng, Aiwu

    2013-01-01

    In the process of neurogenesis, neural progenitor cells (NPCs) cease dividing and differentiate into postmitotic neurons that grow dendrites and an axon, become excitable, and establish synapses with other neurons. Mitochondrial biogenesis and aerobic metabolism provide energy substrates required to support the differentiation, growth and synaptic activity of neurons. Mitochondria may also serve signaling functions and, in this regard, it was recently reported that mitochondria can generate rapid bursts of superoxide (superoxide flashes), the frequency of which changes in response to environmental conditions and signals including oxygen levels and Ca(2+) fluxes. Here we show that the frequency of mitochondrial superoxide flashes increases as embryonic cerebral cortical neurons differentiate from NPCs, and provide evidence that the superoxide flashes serve a signaling function that is critical for the differentiation process. The superoxide flashes are mediated by mitochondrial permeability transition pore (mPTP) opening, and pharmacological inhibition of the mPTP suppresses neuronal differentiation. Moreover, superoxide flashes and neuronal differentiation are inhibited by scavenging of mitochondrial superoxide. Conversely, manipulations that increase superoxide flash frequency accelerate neuronal differentiation. Our findings reveal a regulatory role for mitochondrial superoxide flashes, mediated by mPTP opening, in neuronal differentiation.

  7. AMPK activation by isorhamnetin protects hepatocytes against oxidative stress and mitochondrial dysfunction.

    Science.gov (United States)

    Dong, Guang-Zhi; Lee, Ju-Hee; Ki, Sung Hwan; Yang, Ji Hye; Cho, Il Je; Kang, Seung Ho; Zhao, Rong Jie; Kim, Sang Chan; Kim, Young Woo

    2014-10-05

    Arachidonic acid (AA) is a ω-6 polyunsaturated fatty acid that is found in the phospholipids of membranes and released from the cellular membrane lipid bilayer by phospholipase A2. During this process, AA could produce excess reactive oxygen species and induce apoptosis and mitochondrial dysfunction by selectively inhibiting complexes I and III. Isorhamnetin, an O-methylated flavonol aglycone, has been shown to have cardio-protective, anti-adipogenic, anti-tumor, and anti-inflammatory effects. In the present study, we investigated the effects of isorhamnetin on hepatotoxicity and the underlying mechanisms involved. Our in vitro experiments showed that isorhamnetin dose-dependently blocked the hepatotoxicity induced by treatment with AA plus iron in HepG2 cells. Furthermore, isorhamnetin inhibited the AA+iron induced generation of reactive oxygen species and reduction of glutathione, and subsequently maintained mitochondria membrane potential in AA+iron treated HepG2 cells. In addition, isorhamnetin activated AMP-activated protein kinase (AMPK) by Thr-172 phosphorylation of AMPKα, and this was mediated with Ca2+/calmodulin-dependent protein kinase kinase-2 (CaMKK2), but not liver kinase B1. Experiments using CaMKK2 siRNA or its selective inhibitor, STO-609, revealed the role of CaMKK2 in the isorhamnetin-induced activation of AMPK in HepG2 cells. These results indicate isorhamnetin protects against the hepatotoxic effect of AA plus iron, and suggest that the AMPK pathway is involved in the mechanism underlying the beneficial effect of isorhamnetin in the liver.

  8. Carnosic acid attenuates acute ethanol-induced liver injury via a SIRT1/p66Shc-mediated mitochondrial pathway.

    Science.gov (United States)

    Tian, Xinyao; Hu, Yan; Li, Mingzhu; Xia, Kun; Yin, Jiye; Chen, Juan; Liu, Zhaoqian

    2016-04-01

    Ethanol-induced liver injury is associated with oxidative stress and hepatocyte apoptosis. We previously demonstrated that SIRT1/p66Shc pathway activation attenuates hepatocyte apoptosis in liver ischemia/reperfusion. The current study aimed to investigate whether carnosic acid (CA), a natural antioxidant, can inhibit acute ethanol-induced apoptosis of hepatocytes and to determine the effect of SIRT1/p66Shc on this process. Our results showed that CA pretreatment significantly reduced ethanol-induced histologic damage, serum aminotransferase activity, and oxidative stress in rats. Importantly, CA pretreatment increased SIRT1 expression following ethanol exposure. Furthermore, p66Shc expression was negatively correlated with SIRT1 expression. Consistent with the results demonstrating p66Shc inhibition, CA pretreatment inhibited the release of cytochrome C and apoptosis-inducing factor (AIF) from mitochondria. After exposing L02 cells to ethanol, the increased SIRT1 expression induced by CA was abrogated by pharmacologic SIRT1 inhibition or the use of siRNA against SIRT1. Additionally, SIRT1 inhibition significantly abrogated the suppression of p66Shc expression and mitochondrial translocation induced by CA. Accordingly, CA-induced decreases in the release of cytochrome C and AIF and in mitochondrial apoptosis were nearly abolished by SIRT1 knockdown. These data indicated that CA-activated SIRT1 is protective against ethanol treatment. In summary, CA attenuates acute ethanol-induced liver injury via a SIRT1/p66Shc-mediated mitochondrial pathway.

  9. GASZ and mitofusin-mediated mitochondrial functions are crucial for spermatogenesis.

    Science.gov (United States)

    Zhang, Jingjing; Wang, Qian; Wang, Mingsong; Jiang, Manxi; Wang, Yongsheng; Sun, Yun; Wang, Junpeng; Xie, Taorong; Tang, Chao; Tang, Nannan; Song, Huili; Cui, Di; Chao, Ruihua; Ding, Shuzhe; Ni, Bing; Chen, Xuejin; Wang, Yuan

    2016-02-01

    Nuage is an electron-dense cytoplasmic structure in germ cells that contains ribonucleoproteins and participates in piRNA biosynthesis. Despite the observation that clustered mitochondria are associated with a specific type of nuage called intermitochondrial cement (pi-body), the importance of mitochondrial functions in nuage formation and spermatogenesis is yet to be determined. We show that a germ cell-specific protein GASZ contains a functional mitochondrial targeting signal and is largely localized at mitochondria both endogenously in germ cells and in somatic cells when ectopically expressed. In addition, GASZ interacts with itself at the outer membrane of mitochondria and promotes mitofusion in a mitofusin/MFN-dependent manner. In mice, deletion of the mitochondrial targeting signal reveals that mitochondrial localization of GASZ is essential for nuage formation, mitochondrial clustering, transposon repression, and spermatogenesis. MFN1 deficiency also leads to defects in mitochondrial activity and male infertility. Our data thus reveal a requirement for GASZ and MFN-mediated mitofusion during spermatogenesis.

  10. JNK interaction with Sab mediates ER stress induced inhibition of mitochondrial respiration and cell death.

    Science.gov (United States)

    Win, S; Than, T A; Fernandez-Checa, J C; Kaplowitz, N

    2014-01-09

    Our aim was to better understand the mechanism and importance of sustained c-Jun N-terminal kinase (JNK) activation in endoplasmic reticulum (ER) stress and effects of ER stress on mitochondria by determining the role of mitochondrial JNK binding protein, Sab. Tunicamycin or brefeldin A induced a rapid and marked decline in basal mitochondrial respiration and reserve-capacity followed by delayed mitochondrial-mediated apoptosis. Knockdown of mitochondrial Sab prevented ER stress-induced sustained JNK activation, impaired respiration, and apoptosis, but did not alter the magnitude or time course of activation of ER stress pathways. P-JNK plus adenosine 5'-triphosphate (ATP) added to isolated liver mitochondria promoted superoxide production, which was amplified by addition of calcium and inhibited by a blocking peptide corresponding to the JNK binding site on Sab (KIM1). This peptide also blocked tunicamycin-induced inhibition of cellular respiration. In conclusion, ER stress triggers an interaction of JNK with mitochondrial Sab, which leads to impaired respiration and increased mitochondrial reactive oxygen species, sustaining JNK activation culminating in apoptosis.

  11. Requirements for Carnitine Shuttle-Mediated Translocation of Mitochondrial Acetyl Moieties to the Yeast Cytosol

    Directory of Open Access Journals (Sweden)

    Harmen M. van Rossum

    2016-05-01

    Full Text Available In many eukaryotes, the carnitine shuttle plays a key role in intracellular transport of acyl moieties. Fatty acid-grown Saccharomyces cerevisiae cells employ this shuttle to translocate acetyl units into their mitochondria. Mechanistically, the carnitine shuttle should be reversible, but previous studies indicate that carnitine shuttle-mediated export of mitochondrial acetyl units to the yeast cytosol does not occur in vivo. This apparent unidirectionality was investigated by constitutively expressing genes encoding carnitine shuttle-related proteins in an engineered S. cerevisiae strain, in which cytosolic acetyl coenzyme A (acetyl-CoA synthesis could be switched off by omitting lipoic acid from growth media. Laboratory evolution of this strain yielded mutants whose growth on glucose, in the absence of lipoic acid, was l-carnitine dependent, indicating that in vivo export of mitochondrial acetyl units to the cytosol occurred via the carnitine shuttle. The mitochondrial pyruvate dehydrogenase complex was identified as the predominant source of acetyl-CoA in the evolved strains. Whole-genome sequencing revealed mutations in genes involved in mitochondrial fatty acid synthesis (MCT1, nuclear-mitochondrial communication (RTG2, and encoding a carnitine acetyltransferase (YAT2. Introduction of these mutations into the nonevolved parental strain enabled l-carnitine-dependent growth on glucose. This study indicates intramitochondrial acetyl-CoA concentration and constitutive expression of carnitine shuttle genes as key factors in enabling in vivo export of mitochondrial acetyl units via the carnitine shuttle.

  12. Prohibitin reduces mitochondrial free radical production and protects brain cells from different injury modalities

    Science.gov (United States)

    Zhou, Ping; Qian, Liping; D’Aurelio, Marilena; Cho, Sunghee; Wang, Gang; Manfredi, Giovanni; Pickel, Virginia; Iadecola, Costantino

    2012-01-01

    Prohibitin is an essential mitochondrial protein that has been implicated in a wide variety of functions in many cell types, but its role in neurons remains unclear. In a proteomic screen of rat brains in which ischemic tolerance was induced by electrical stimulation of the cerebellar fastigial nucleus, we found that prohibitin is upregulated in mitochondria. This observation prompted us to investigate the role of prohibitin in neuronal death and survival. We found that prohibitin is upregulated also in the ischemic tolerance induced by transient ischemia in vivo, or oxygen-glucose deprivation in neuronal cultures. Cell fractionation and electron microscopic immunolabeling studies demonstrated that prohibitin is localized to neuronal mitochondria. Upregulation of prohibitin in neuronal cultures or hippocampal slices was markedly neuroprotective, whereas prohibitin gene-silencing increased neuronal vulnerability, an effect associated with loss of mitochondrial membrane potential and increased mitochondrial production of reactive oxygen species. Prohibitin upregulation was associated with reduced production of reactive oxygen species in mitochondria exposed to the complex I inhibitor rotenone. In addition, prohibitin protected complex I activity from the inhibitory effects of rotenone. These observations, collectively, establish prohibitin as an endogenous neuroprotective protein involved in ischemic tolerance. Prohibitin exerts beneficial effects on neurons by reducing mitochondrial free radical production. The data with complex I activity suggest that prohibitin may stabilize the function of complex I. The protective effect of prohibitin has potential translational relevance in diseases of the nervous system associated with mitochondrial dysfunction and oxidative stress. PMID:22238093

  13. Novel incretin analogues improve autophagy and protect from mitochondrial stress induced by rotenone in SH-SY5Y cells.

    Science.gov (United States)

    Jalewa, Jaishree; Sharma, Mohit Kumar; Hölscher, Christian

    2016-10-01

    Currently, there is no viable treatment available for Parkinson's disease (PD) that stops or reverses disease progression. Interestingly, studies testing the glucagon-like-peptide-1 (GLP-1) mimetic Exendin-4 have shown neuroprotective/neurorestorative properties in pre-clinical tests and in a pilot clinical study of PD. Incretin analogues were originally developed to treat type 2 diabetes and several are currently on the market. In this study, we tested novel incretin analogues on the dopaminergic SH-SY5Y neuroblastoma cells against a toxic mitochondrial complex I inhibitor, Rotenone. Here, we investigate for the first time the effects of six different incretin receptor agonists - Liraglutide, D-Ser2-Oxyntomodulin, a GLP-1/GIP Dual receptor agonist, dAla(2)-GIP-GluPal, Val(8)GLP-1-GluPal and exendin-4. Post-treatment with doses of 1, 10 or 100 nM of incretin analogues for 12 h increased the survival of SH-SY5Y cells treated with 1 μM Rotenone for 12 h. Furthermore, we studied the post-treatment effect of 100 nM incretin analogues against 1 μM Rotenone stress on apoptosis, mitochondrial stress and autophagy markers. We found significant protective effects of the analogues against Rotenone stress on cell survival and on mitochondrial and autophagy-associated markers. The novel GLP-1/GIP Dual receptor agonist was superior and effective at a tenfold lower concentration compared to the other analogues. Using the Phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, we further show that the neuroprotective effects are partially PI3K-independent. Our data suggest that the neuroprotective properties exhibited by incretin analogues against Rotenone stress involve enhanced autophagy, increased Akt-mediated cell survival and amelioration of mitochondrial dysfunction. These mechanisms can explain the neuroprotective effects of incretin analogues reported in clinical trials. GLP-1, GIP and dual incretin receptor agonists showed protective effects in SH-SY5Y cells

  14. How the Wnt signaling pathway protects from neurodegeneration: the mitochondrial scenario

    Science.gov (United States)

    Arrázola, Macarena S.; Silva-Alvarez, Carmen; Inestrosa, Nibaldo C.

    2015-01-01

    Alzheimer’s disease (AD) is the most common neurodegenerative disorder and is characterized by progressive memory loss and cognitive decline. One of the hallmarks of AD is the overproduction of amyloid-beta aggregates that range from the toxic soluble oligomer (Aβo) form to extracellular accumulations in the brain. Growing evidence indicates that mitochondrial dysfunction is a common feature of neurodegenerative diseases and is observed at an early stage in the pathogenesis of AD. Reports indicate that mitochondrial structure and function are affected by Aβo and can trigger neuronal cell death. Mitochondria are highly dynamic organelles, and the balance between their fusion and fission processes is essential for neuronal function. Interestingly, in AD, the process known as “mitochondrial dynamics” is also impaired by Aβo. On the other hand, the activation of the Wnt signaling pathway has an essential role in synaptic maintenance and neuronal functions, and its deregulation has also been implicated in AD. We have demonstrated that canonical Wnt signaling, through the Wnt3a ligand, prevents the permeabilization of mitochondrial membranes through the inhibition of the mitochondrial permeability transition pore (mPTP), induced by Aβo. In addition, we showed that non-canonical Wnt signaling, through the Wnt5a ligand, protects mitochondria from fission-fusion alterations in AD. These results suggest new approaches by which different Wnt signaling pathways protect neurons in AD, and support the idea that mitochondria have become potential therapeutic targets for the treatment of neurodegenerative disorders. Here we discuss the neuroprotective role of the canonical and non-canonical Wnt signaling pathways in AD and their differential modulation of mitochondrial processes, associated with mitochondrial dysfunction and neurodegeneration. PMID:25999816

  15. High resolution respirometry analysis of polyethylenimine-mediated mitochondrial energy crisis and cellular stress

    DEFF Research Database (Denmark)

    Hall, Arnaldur; Larsen, Anna Karina; Parhamifar, Ladan

    2013-01-01

    of PEI-mediated plasma membrane damage and subsequent ATP leakage to the extracellular medium. Studies with freshly isolated mouse liver mitochondria corroborated with bioenergetic findings and demonstrated parallel polycation concentration- and time-dependent changes in state 2 and state 4o oxygen flux...... and spectrophotometry analysis of cytochrome c oxidase activity we were able to identify complex IV (cytochrome c oxidase) as a likely specific site of PEI mediated inhibition within the electron transport system. Unraveling the mechanisms of PEI-mediated mitochondrial energy crisis is central for combinatorial design...

  16. A mitochondrial pathway for biosynthesis of lipid mediators

    Science.gov (United States)

    Tyurina, Yulia Y.; Poloyac, Samuel M.; Tyurin, Vladimir A.; Kapralov, Alexander A.; Jiang, Jianfei; Anthonymuthu, Tamil Selvan; Kapralova, Valentina I.; Vikulina, Anna S.; Jung, Mi-Yeon; Epperly, Michael W.; Mohammadyani, Dariush; Klein-Seetharaman, Judith; Jackson, Travis C.; Kochanek, Patrick M.; Pitt, Bruce R.; Greenberger, Joel S.; Vladimirov, Yury A.; Bayır, Hülya; Kagan, Valerian E.

    2014-06-01

    The central role of mitochondria in metabolic pathways and in cell-death mechanisms requires sophisticated signalling systems. Essential in this signalling process is an array of lipid mediators derived from polyunsaturated fatty acids. However, the molecular machinery for the production of oxygenated polyunsaturated fatty acids is localized in the cytosol and their biosynthesis has not been identified in mitochondria. Here we report that a range of diversified polyunsaturated molecular species derived from a mitochondria-specific phospholipid, cardiolipin (CL), is oxidized by the intermembrane-space haemoprotein, cytochrome c. We show that a number of oxygenated CL species undergo phospholipase A2-catalysed hydrolysis and thus generate multiple oxygenated fatty acids, including well-known lipid mediators. This represents a new biosynthetic pathway for lipid mediators. We demonstrate that this pathway, which includes the oxidation of polyunsaturated CLs and accumulation of their hydrolysis products (oxygenated linoleic, arachidonic acids and monolysocardiolipins), is activated in vivo after acute tissue injury.

  17. Calcium signaling-mediated endogenous protection of cell energetics in the acutely diabetic myocardium

    National Research Council Canada - National Science Library

    Ziegelhoffer, Attila; Waczulikova, Iveta; Ferko, Miroslav; Kincelova, Dana; Ziegelhoffer, Barbara; Ravingerova, Tana; Cagalinec, Michal; Schonburg, Markus; Ziegelhoeffer, Tibor; Sikurova, Libusa; Ulicna, Olga; Mujkosova, Jana

    2009-01-01

    In acute diabetic myocardium, calcium signals propagated by intracellular calcium transients participate in the protection of cell energetics via upregulating the formation of mitochondrial energy transition pores (ETP...

  18. Protective effect of Phyllanthus fraternus against bromobenzene-induced mitochondrial dysfunction in rat kidney

    Institute of Scientific and Technical Information of China (English)

    Vadde Ramakrishna; Sriram Gopi; Oruganti H.Setty

    2012-01-01

    Phyllanthus fraternus (PF) (Euphorbiaceae) is used in ancient Indian traditional phytomedicine to treat various human diseases including hepatic and renal disorders.The present study was designed to investigate the protective effect of PF aqueous extract against bromobenzene-induced mitochondrial dysfunction in rat kidney,compared with vitamin E used as positive control.Male Wistar rats divided into six (A-F) groups and the experimental animals were administered bromobenzene with or without prior administration of PF extract or vitamin E.Animals were sacrificed and the kidneys obtained for studying mitochondrial function and histopathology.Administration of bromobenzene caused significant changes,including decrease in the mitochondrial respiration and P/O ratios,an increase in lipid peroxidation and protein oxidation,and a decrease in the activities of antioxidant enzymes (catalase,superoxide dismutase,glutathione reductase,and glutathione peroxidase) in mitochondria with significant histopathological changes in the kidney.However,prior administration of the PF extract showed significant protection against bromobenzene induced renal damage by reversing all above parameters.Mitochondrial dysfunction induced by bromobenzene was protected much better with the PF extract than with vitamin E.These results suggested that the Phyllanthus fraternus extract is an efficient armament against nephrotoxicity induced by bromobenzene.

  19. Mitochondria-targeted esculetin alleviates mitochondrial dysfunction by AMPK-mediated nitric oxide and SIRT3 regulation in endothelial cells: potential implications in atherosclerosis.

    Science.gov (United States)

    Karnewar, Santosh; Vasamsetti, Sathish Babu; Gopoju, Raja; Kanugula, Anantha Koteswararao; Ganji, Sai Krishna; Prabhakar, Sripadi; Rangaraj, Nandini; Tupperwar, Nitin; Kumar, Jerald Mahesh; Kotamraju, Srigiridhar

    2016-04-11

    Mitochondria-targeted compounds are emerging as a new class of drugs that can potentially alter the pathophysiology of those diseases where mitochondrial dysfunction plays a critical role. We have synthesized a novel mitochondria-targeted esculetin (Mito-Esc) with an aim to investigate its effect during oxidative stress-induced endothelial cell death and angiotensin (Ang)-II-induced atherosclerosis in ApoE(-/-) mice. Mito-Esc but not natural esculetin treatment significantly inhibited H2O2- and Ang-II-induced cell death in human aortic endothelial cells by enhancing NO production via AMPK-mediated eNOS phosphorylation. While L-NAME (NOS inhibitor) significantly abrogated Mito-Esc-mediated protective effects, Compound c (inhibitor of AMPK) significantly decreased Mito-Esc-mediated increase in NO production. Notably, Mito-Esc promoted mitochondrial biogenesis by enhancing SIRT3 expression through AMPK activation; and restored H2O2-induced inhibition of mitochondrial respiration. siSIRT3 treatment not only completely reversed Mito-Esc-mediated mitochondrial biogenetic marker expressions but also caused endothelial cell death. Furthermore, Mito-Esc administration to ApoE(-/-) mice greatly alleviated Ang-II-induced atheromatous plaque formation, monocyte infiltration and serum pro-inflammatory cytokines levels. We conclude that Mito-Esc is preferentially taken up by the mitochondria and preserves endothelial cell survival during oxidative stress by modulating NO generation via AMPK. Also, Mito-Esc-induced SIRT3 plays a pivotal role in mediating mitochondrial biogenesis and perhaps contributes to its anti-atherogenic effects.

  20. Mitochondrial dysfunction as a mediator of hippocampal apoptosis in a model of hepatic encephalopathy.

    Science.gov (United States)

    Bustamante, J; Lores-Arnaiz, S; Tallis, S; Roselló, D M; Lago, N; Lemberg, A; Boveris, A; Perazzo, J C

    2011-08-01

    In this study, we describe the presence of apoptosis, associated with a mitochondrial dysfunction in the hippocampus of animals in an experimental model defined as minimal hepatic encephalopathy (MHE). This experimental model was studied after 10 days of induced portal vein calibrated stricture, leading to portal hypertension and to a moderate hyperammonemia, without the presence of other evident central nervous system changes. The molecular mechanisms here proposed indicate the presence of apoptotic intrinsic pathways that point to hippocampal mitochondria as an important mediator of apoptosis in this experimental model. In this model of MHE, the presence of DNA fragmentation is documented by 2.3-times increased number of TUNEL-positive cells. These findings together with a higher ratio of the Bcl-2 family members Bax/Bcl-xL in the outer mitochondrial membrane of the MHE animals together with 11% of cytochrome c release indicate the presence of apoptosis in this experimental model. A detailed analysis of the hippocampal mitochondrial physiology was performed after mitochondrial isolation. The determination of the respiratory rate in the presence of malate plus glutamate and ADP showed a 45% decrease in respiratory control in MHE animals as compared with the sham group. A marked decrease of cytochrome oxidase (complex IV of the electron transport chain) was also observed, showing 46% less activity in hippocampal mitochondria from MHE animals. In addition, mitochondria from these animals showed less ability to maintain membrane potential (ΔΨ (m)) which was 13% lower than the sham group. Light scattering experiments showed that mitochondria from MHE animals were more sensitive to swell in the presence of increased calcium concentrations as compared with the sham group. In addition, in vitro studies performed in mitochondria from sham animals showed that mitochondrial permeability transition (MPT) could be a mitochondrial mediator of the apoptotic signaling in the

  1. Influenza virus induces apoptosis via BAD-mediated mitochondrial dysregulation.

    Science.gov (United States)

    Tran, Anh T; Cortens, John P; Du, Qiujiang; Wilkins, John A; Coombs, Kevin M

    2013-01-01

    Influenza virus infection results in host cell death and major tissue damage. Specific components of the apoptotic pathway, a signaling cascade that ultimately leads to cell death, are implicated in promoting influenza virus replication. BAD is a cell death regulator that constitutes a critical control point in the intrinsic apoptosis pathway, which occurs through the dysregulation of mitochondrial outer membrane permeabilization and the subsequent activation of downstream apoptogenic factors. Here we report a novel proviral role for the proapoptotic protein BAD in influenza virus replication. We show that influenza virus-induced cytopathology and cell death are considerably inhibited in BAD knockdown cells and that both virus replication and viral protein production are dramatically reduced, which suggests that virus-induced apoptosis is BAD dependent. Our data showed that influenza viruses induced phosphorylation of BAD at residues S112 and S136 in a temporal manner. Viral infection also induced BAD cleavage, late in the viral life cycle, to a truncated form that is reportedly a more potent inducer of apoptosis. We further demonstrate that knockdown of BAD resulted in reduced cytochrome c release and suppression of the intrinsic apoptotic pathway during influenza virus replication, as seen by an inhibition of caspases-3, caspase-7, and procyclic acidic repetitive protein (PARP) cleavage. Our data indicate that influenza viruses carefully modulate the activation of the apoptotic pathway that is dependent on the regulatory function of BAD and that failure of apoptosis activation resulted in unproductive viral replication.

  2. Mechanisms of p53-mediated mitochondrial membrane permeabilization

    Institute of Scientific and Technical Information of China (English)

    Eugenia Morselli; Lorenzo Galluzzi; Guido Kroemer

    2008-01-01

    @@ The p53 protein is mutated or inactivated in more than 50% of human cancers, underscoring its cardinal importance as an oncosuppressor, p53 is expressed in all nucleated cells and can be activated by a plethora of post-transcriptional modifications (in particular by the phosphorylation of critical serine residues), as well as by the inhibition of its degradation (mainly mediated by the E3 ubiquitin ligase MDM2).

  3. Energy, ageing, fidelity and sex: oocyte mitochondrial DNA as a protected genetic template.

    Science.gov (United States)

    de Paula, Wilson B M; Lucas, Cathy H; Agip, Ahmed-Noor A; Vizcay-Barrena, Gema; Allen, John F

    2013-07-19

    Oxidative phosphorylation couples ATP synthesis to respiratory electron transport. In eukaryotes, this coupling occurs in mitochondria, which carry DNA. Respiratory electron transport in the presence of molecular oxygen generates free radicals, reactive oxygen species (ROS), which are mutagenic. In animals, mutational damage to mitochondrial DNA therefore accumulates within the lifespan of the individual. Fertilization generally requires motility of one gamete, and motility requires ATP. It has been proposed that oxidative phosphorylation is nevertheless absent in the special case of quiescent, template mitochondria, that these remain sequestered in oocytes and female germ lines and that oocyte mitochondrial DNA is thus protected from damage, but evidence to support that view has hitherto been lacking. Here we show that female gametes of Aurelia aurita, the common jellyfish, do not transcribe mitochondrial DNA, lack electron transport, and produce no free radicals. In contrast, male gametes actively transcribe mitochondrial genes for respiratory chain components and produce ROS. Electron microscopy shows that this functional division of labour between sperm and egg is accompanied by contrasting mitochondrial morphology. We suggest that mitochondrial anisogamy underlies division of any animal species into two sexes with complementary roles in sexual reproduction. We predict that quiescent oocyte mitochondria contain DNA as an unexpressed template that avoids mutational accumulation by being transmitted through the female germ line. The active descendants of oocyte mitochondria perform oxidative phosphorylation in somatic cells and in male gametes of each new generation, and the mutations that they accumulated are not inherited. We propose that the avoidance of ROS-dependent mutation is the evolutionary pressure underlying maternal mitochondrial inheritance and the developmental origin of the female germ line.

  4. Pemphigus vulgaris antibodies target the mitochondrial nicotinic acetylcholine receptors that protect keratinocytes from apoptolysis.

    Science.gov (United States)

    Chernyavsky, Alex; Chen, Yumay; Wang, Ping H; Grando, Sergei A

    2015-11-01

    The mechanism of detachment and death of keratinocytes in pemphigus vulgaris (PV) involves pro-apoptotic action of constellations of autoantibodies determining disease severity and response to treatment. The presence of antibodies to nicotinic acetylcholine receptors (nAChRs) and the therapeutic efficacy of cholinomimetics in PV is well-established. Recently, adsorption of anti-mitochondrial antibodies abolished the ability of PVIgGs to cause acantholysis, demonstrating their pathophysiological significance. Since, in addition to cell membrane, nAChRs are also present on the mitochondrial outer membrane, wherein they act to prevent activation of intrinsic (mitochondrial apoptosis), we hypothesized that mitochondrial (mt)-nAChRs might be targeted by PVIgGs. To test this hypothesis, we employed the immunoprecipitation-western blot assay of keratinocyte mitochondrial proteins that visualized the α3, α5, α7, α9, α10, β2 and β4 mt-nAChR subunits precipitated by PV IgGs, suggesting that functions of mt-nAChRs are compromised in PV. To pharmacologically counteract the pro-apoptotic action of anti-mitochondrial antibodies in PV, we exposed naked keratinocyte mitochondria to PVIgGs in the presence of the nicotinic agonist nicotine ± antagonists, and measured cytochrome c (CytC) release. Nicotine abolished PVIgG-dependent CytC release, showing a dose-dependent effect, suggesting that protection of mitochondria can be a novel mechanism of therapeutic action of nicotinic agonists in PV. The obtained results indicated that the mt-nAChRs targeted by anti-mitochondrial antibodies produced by PV patients are coupled to inhibition of CytC release, and that nicotinergic stimulation can abolish PVIgG-dependent activation of intrinsic apoptosis in KCs. Future studies should determine if and how the distinct anti-mt-nAChR antibodies penetrate KCs and correlate with disease severity.

  5. Intracellular Ca2+ release through ryanodine receptors contributes to AMPA receptor-mediated mitochondrial dysfunction and ER stress in oligodendrocytes

    Science.gov (United States)

    Ruiz, A; Matute, C; Alberdi, E

    2010-01-01

    Overactivation of ionotropic glutamate receptors in oligodendrocytes induces cytosolic Ca2+ overload and excitotoxic death, a process that contributes to demyelination and multiple sclerosis. Excitotoxic insults cause well-characterized mitochondrial alterations and endoplasmic reticulum (ER) dysfunction, which is not fully understood. In this study, we analyzed the contribution of ER-Ca2+ release through ryanodine receptors (RyRs) and inositol triphosphate receptors (IP3Rs) to excitotoxicity in oligodendrocytes in vitro. First, we observed that oligodendrocytes express all previously characterized RyRs and IP3Rs. Blockade of Ca2+-induced Ca2+ release by TMB-8 following α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor-mediated insults attenuated both oligodendrocyte death and cytosolic Ca2+ overload. In turn, RyR inhibition by ryanodine reduced as well the Ca2+ overload whereas IP3R inhibition was ineffective. Furthermore, AMPA-triggered mitochondrial membrane depolarization, oxidative stress and activation of caspase-3, which in all instances was diminished by RyR inhibition. In addition, we observed that AMPA induced an ER stress response as revealed by α subunit of the eukaryotic initiation factor 2α phosphorylation, overexpression of GRP chaperones and RyR-dependent cleavage of caspase-12. Finally, attenuating ER stress with salubrinal protected oligodendrocytes from AMPA excitotoxicity. Together, these results show that Ca2+ release through RyRs contributes to cytosolic Ca2+ overload, mitochondrial dysfunction, ER stress and cell death following AMPA receptor-mediated excitotoxicity in oligodendrocytes. PMID:21364659

  6. Human REV3 DNA Polymerase Zeta Localizes to Mitochondria and Protects the Mitochondrial Genome.

    Science.gov (United States)

    Singh, Bhupendra; Li, Xiurong; Owens, Kjerstin M; Vanniarajan, Ayyasamy; Liang, Ping; Singh, Keshav K

    2015-01-01

    To date, mitochondrial DNA polymerase γ (POLG) is the only polymerase known to be present in mammalian mitochondria. A dogma in the mitochondria field is that there is no other polymerase present in the mitochondria of mammalian cells. Here we demonstrate localization of REV3 DNA polymerase in the mammalian mitochondria. We demonstrate localization of REV3 in the mitochondria of mammalian tissue as well as cell lines. REV3 associates with POLG and mitochondrial DNA and protects the mitochondrial genome from DNA damage. Inactivation of Rev3 leads to reduced mitochondrial membrane potential, reduced OXPHOS activity, and increased glucose consumption. Conversely, inhibition of the OXPHOS increases expression of Rev3. Rev3 expression is increased in human primary breast tumors and breast cancer cell lines. Inactivation of Rev3 decreases cell migration and invasion, and localization of Rev3 in mitochondria increases survival and the invasive potential of cancer cells. Taken together, we demonstrate that REV3 functions in mammalian mitochondria and that mitochondrial REV3 is associated with the tumorigenic potential of cells.

  7. Chaperone-Mediated Autophagy and Mitochondrial Homeostasis in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Ruixin Yang

    2016-01-01

    Full Text Available Parkinson’s disease (PD, a complex neurodegenerative disorder, is pathologically characterized by the formation of Lewy bodies and loss of dopaminergic neurons in the substantia nigra pars compacta (SNc. Mitochondrial dysfunction is considered to be one of the most important causative mechanisms. In addition, dysfunction of chaperone-mediated autophagy (CMA, one of the lysosomal proteolytic pathways, has been shown to play an important role in the pathogenesis of PD. An exciting and important development is recent finding that CMA and mitochondrial quality control may be linked. This review summarizes the studies revealing the link between autophagy and mitochondrial function. Discussions are focused on the connections between CMA and mitochondrial failure and on the role of MEF2D, a neuronal survival factor, in mediating the regulation of mitochondria in the context of CMA. These new findings highlight the need to further explore the possibility of targeting the MEF2D-mitochondria-CMA network in both understanding the PD pathogenesis and developing novel therapeutic strategies.

  8. Mitochondrial UCP4 mediates an adaptive shift in energy metabolism and increases the resistance of neurons to metabolic and oxidative stress.

    Science.gov (United States)

    Liu, Dong; Chan, Sic L; de Souza-Pinto, Nadja C; Slevin, John R; Wersto, Robert P; Zhan, Ming; Mustafa, Khadija; de Cabo, Rafael; Mattson, Mark P

    2006-01-01

    The high-metabolic demand of neurons and their reliance on glucose as an energy source places them at risk for dysfunction and death under conditions of metabolic and oxidative stress. Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins implicated in the regulation of mitochondrial membrane potential (Deltapsim) and cellular energy metabolism. The authors cloned UCP4 cDNA from mouse and rat brain, and demonstrate that UCP4 mRNA is expressed abundantly in brain and at particularly high levels in populations of neurons believed to have high-energy requirements. Neural cells with increased levels of UCP4 exhibit decreased Deltapsim, reduced reactive oxygen species (ROS) production and decreased mitochondrial calcium accumulation. UCP4 expressing cells also exhibited changes of oxygen-consumption rate, GDP sensitivity, and response of Deltapsim to oligomycin that were consistent with mitochondrial uncoupling. UCP4 modulates neuronal energy metabolism by increasing glucose uptake and shifting the mode of ATP production from mitochondrial respiration to glycolysis, thereby maintaining cellular ATP levels. The UCP4-mediated shift in energy metabolism reduces ROS production and increases the resistance of neurons to oxidative and mitochondrial stress. Knockdown of UCP4 expression by RNA interference in primary hippocampal neurons results in mitochondrial calcium overload and cell death. UCP4-mRNA expression is increased in neurons exposed to cold temperatures and in brain cells of rats maintained on caloric restriction, suggesting a role for UCP4 in the previously reported antiageing and neuroprotective effects of caloric restriction. By shifting energy metabolism to reduce ROS production and cellular reliance on mitochondrial respiration, UCP4 can protect neurons against oxidative stress and calcium overload.

  9. RNAi-mediated crop protection against insects.

    Science.gov (United States)

    Price, Daniel R G; Gatehouse, John A

    2008-07-01

    Downregulation of the expression of specific genes through RNA interference (RNAi), has been widely used for genetic research in insects. The method has relied on the injection of double-stranded RNA (dsRNA), which is not possible for practical applications in crop protection. By contrast, specific suppression of gene expression in nematodes is possible through feeding with dsRNA. This approach was thought to be unfeasible in insects, but recent results have shown that dsRNA fed as a diet component can be effective in downregulating targeted genes. More significantly, expression of dsRNA directed against suitable insect target genes in transgenic plants has been shown to give protection against pests, opening the way for a new generation of insect-resistant crops.

  10. Improved mitochondrial function underlies the protective effect of pirfenidone against tubulointerstitial fibrosis in 5/6 nephrectomized rats.

    Science.gov (United States)

    Chen, Jun-Feng; Liu, Hong; Ni, Hai-Feng; Lv, Lin-Li; Zhang, Ming-Hui; Zhang, Ai-Hua; Tang, Ri-Ning; Chen, Ping-Sheng; Liu, Bi-Cheng

    2013-01-01

    Dysfunctional mitochondria participate in the progression of chronic kidney disease (CKD). Pirfenidone is a newly identified anti-fibrotic drug. However, its mechanism remains unclear. Mitochondrial dysfunction is an early event that occurs prior to the onset of renal fibrosis. In this context, we investigated the protective effect of pirfenidone on mitochondria and its relevance to apoptosis and oxidative stress in renal proximal tubular cells. A remnant kidney rat model was established. Human renal proximal tubular epithelial cells (HK2) using rotenone, a mitochondrial respiratory chain complex Ι inhibitor were further investigated in vitro to examine the mitochondrial protective effect of pirfenidone. Pirfenidone protected mitochondrial structures and functions by stabilizing the mitochondrial membrane potential, maintaining ATP production and improving the mitochondrial DNA (mtDNA) copy number. Pirfenidone decreased tubular cell apoptosis by inhibiting the mitochondrial apoptotic signaling pathway. Pirfenidone also reduced oxidative stress by enhancing manganese superoxide dismutase (Mn-SOD) and inhibiting intracellular reactive oxygen species (ROS) generation, which suggested that the anti-oxidant effects occurred at least partially via the mitochondrial pathway. Pirfenidone may be effective prior to the onset of renal fibrosis because this drug exerts its anti-fibrotic effect by protection of mitochondria in renal proximal tubular cells.

  11. Improved mitochondrial function underlies the protective effect of pirfenidone against tubulointerstitial fibrosis in 5/6 nephrectomized rats.

    Directory of Open Access Journals (Sweden)

    Jun-Feng Chen

    Full Text Available Dysfunctional mitochondria participate in the progression of chronic kidney disease (CKD. Pirfenidone is a newly identified anti-fibrotic drug. However, its mechanism remains unclear. Mitochondrial dysfunction is an early event that occurs prior to the onset of renal fibrosis. In this context, we investigated the protective effect of pirfenidone on mitochondria and its relevance to apoptosis and oxidative stress in renal proximal tubular cells. A remnant kidney rat model was established. Human renal proximal tubular epithelial cells (HK2 using rotenone, a mitochondrial respiratory chain complex Ι inhibitor were further investigated in vitro to examine the mitochondrial protective effect of pirfenidone. Pirfenidone protected mitochondrial structures and functions by stabilizing the mitochondrial membrane potential, maintaining ATP production and improving the mitochondrial DNA (mtDNA copy number. Pirfenidone decreased tubular cell apoptosis by inhibiting the mitochondrial apoptotic signaling pathway. Pirfenidone also reduced oxidative stress by enhancing manganese superoxide dismutase (Mn-SOD and inhibiting intracellular reactive oxygen species (ROS generation, which suggested that the anti-oxidant effects occurred at least partially via the mitochondrial pathway. Pirfenidone may be effective prior to the onset of renal fibrosis because this drug exerts its anti-fibrotic effect by protection of mitochondria in renal proximal tubular cells.

  12. Protection of melatonin against damage of sperm mito-chondrial function induced by reactive oxygen species

    Institute of Scientific and Technical Information of China (English)

    Xue-JunShang; Yu-FengHuang; Zhang-QunYe; XiaoYu; Wan-JiaGu

    2004-01-01

    Aim: To study the mitochondrial function damage of sperm in-duced by reactive oxygen species (ROS) and the protection of melatonin (MLT) against the damage. Methods: Normal function spermatozoa were selected from semen samples by Percoll gradi-ent centrifugation technique. The ROS generated by the hypoxan-thine xanthine oxidase system was incubated with the normal sper-matozoa in the presence or absence of MLT (6 retool/L) for 30 and 60 minutes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zaja, Ivan [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Bai, Xiaowen, E-mail: xibai@mcw.edu [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Liu, Yanan; Kikuchi, Chika; Dosenovic, Svjetlana; Yan, Yasheng; Canfield, Scott G. [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Bosnjak, Zeljko J. [Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States)

    2014-10-31

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

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

    Science.gov (United States)

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

    2015-03-10

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

  15. The mitochondrial housekeeping gene 16S is inappropriate as an internal standard in comparative studies of rare mitochondrial transcripts using S1-nuclease protection assays

    Directory of Open Access Journals (Sweden)

    Sandra Ebert

    2010-04-01

    Full Text Available The analysis of rare mitochondrial transcripts derived from the L-strand of the mitochondrial genome requires a sensitive method such as the S1-nuclease protection assay. We examined whether the ribosomal mitochon­drial transcript 16S is suitable as an internal standard in a multiplex S1-nuclease protection assay for the measurement of different mitochondrial transcripts. For reliable quantification of rare mitochondrial transcripts with the RNase protection assay, a minimum of 2 μg of total RNA is necessary. Standard curves of 16S RNA produced with total RNA from human kidney, liver, brain, and a human neuroblastoma cell line (SH-SY5Y revealed dose-response relationships that were saturated already at less than 0.5 μg of total RNA. Therefore, 16S is inappropriate as an internal standard for analyzing mitochondrial transcripts with RNase protection assays when more than 0.5 μg of total RNA have to be analyzed.

  16. Protective role of malvidin-3-glucoside on peroxynitrite-induced damage in endothelial cells by counteracting reactive species formation and apoptotic mitochondrial pathway.

    Science.gov (United States)

    Paixão, Joana; Dinis, Teresa C P; Almeida, Leonor M

    2012-01-01

    The health-promoted benefits of anthocyanins, including vascular protective effects and antiatherogenic properties, have now been recognized, but the involved molecular mechanisms have not been well elucidated. Following our previous work on cytoprotective mechanisms of some anthocyanins against apoptosis triggered by peroxynitrite in endothelial cells, here we investigated the protective role of malvidin-3-glucoside, a major dietary anthocyanin, on such deleterious process, by exploring the interference on cellular reactive species formation and on apoptotic mitochondrial pathway. Preincubation of cells with 25 μM malvidin-3-glucoside protected efficiently endothelial cells from peroxynitrite-promoted apoptotic death, an effect which may be partially mediated by its ability to decrease the formation of reactive species after cell aggression, as assessed by the dichlorodihydrofluorescein diacetate assay and by carbonyl groups formation. Moreover, malvidin-3-glucoside inhibited mitochondrial apoptotic signaling pathways induced by peroxynitrite, by counteracting mitochondrial membrane depolarization, the activation of caspase-3 and -9, and the increase in the expression of the proapoptotic Bax protein. Altogether, our data expands our knowledge about the molecular mechanisms underlying the vascular protection afforded by malvidin-3-glucoside, and anthocyanins in general, in the context of prevention of endothelial dysfunction and atherosclerosis.

  17. Protective effect of bacoside A on cigarette smoking-induced brain mitochondrial dysfunction in rats.

    Science.gov (United States)

    Anbarasi, Kothandapani; Vani, Ganapathy; Devi, Chennam Srinivasulu Shyamala

    2005-01-01

    Chronic exposure to cigarette smoke affects the structure and function of mitochondria, which may account for the pathogenesis of smoking-related diseases. Bacopa monniera Linn., used in traditional Indian medicine for various neurological disorders, was shown to possess mitrochondrial membrane-stabilizing properties in the rat brain during exposure to morphine. We investigated the protective effect of bacoside A, the active principle of Bacopa monniera, against mitochondrial dysfunction in rat brain induced by cigarette smoke. Male Wistar albino rats were exposed to cigarette smoke and administered bacoside A for a period of 12 weeks. The mitochondrial damage in the brain was assessed by examining the levels of lipid peroxides, cholesterol, phospholipid, cholesterol/phospholipid (C/P) ratio, and the activities of isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, NADH dehydrogenase, and cytochrome C oxidase. The oxidative phosphorylation (rate of succinate oxidation, respiratory control ratio and ADP/O ratio, and the levels of ATP) was evaluated for the assessment of mitochondrial functional capacity. We found significantly elevated levels of lipid peroxides, cholesterol, and C/P ratio, and decreased levels of phospholipids and mitochondrial enzymes in the rats exposed to cigarette smoke. Measurement of oxidative phosphorylation revealed a marked depletion in all the variables studied. Administration of bacoside A prevented the structural and functional impairment of mitochondria upon exposure to cigarette smoke. From the results, we suggest that chronic cigarette smoke exposure induces damage to the mitochondria and that bacoside A protects the brain from this damage by maintaining the structural and functional integrity of the mitochondrial membrane.

  18. Hydrogen sulfide protects against endoplasmic reticulum stress and mitochondrial injury in nucleus pulposus cells and ameliorates intervertebral disc degeneration.

    Science.gov (United States)

    Xu, Daoliang; Jin, Haiming; Wen, Jianxia; Chen, Jiaoxiang; Chen, Deheng; Cai, Ningyu; Wang, Yongli; Wang, Jianle; Chen, Yu; Zhang, Xiaolei; Wang, Xiangyang

    2017-03-01

    It has been suggested that excessive apoptosis in intervertebral disc cells induced by inflammatory cytokines, such as interleukin (IL)-1β, is related to the process of intervertebral disc degeneration (IVDD). Hydrogen sulfide (H2S), a gaseous signaling molecule, has drawn attention for its anti-apoptosis role in various pathophysiological processes in degenerative diseases. To date, there has been no investigation of the correlation of H2S production and IVDD or of the effects of H2S on IL-1β-induced apoptosis in nucleus pulposus (NP) cells. Here, we found that the expression levels of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), two key enzymes in the generation of H2S, were significantly decreased in human degenerate NP tissues as well as in IL-1β-treated NP cells. NaHS (H2S donor) administration showed a protective effect by inhibiting the endoplasmic reticulum (ER) stress response and mitochondrial dysfunction induced by IL-1β stimulation in vitro, the effect was related to activation of the PI3K/Akt and ERK1/2 signaling pathways. Suppression of these pathways by specific inhibitors, LY294002 and PD98059, partially reduced the protective effect of NaHS. Moreover, in the percutaneous needle puncture disc degeneration rat tail model, disc degeneration was partially reversed by NaHS administration. Taken together, our results suggest that H2S plays a protective role in IVDD and the underlying mechanism involves PI3K/Akt and ERK1/2 signaling pathways-mediated suppression of ER stress and mitochondrial dysfunction in IL-1β-induced NP cells.

  19. Dieldrin promotes proteolytic cleavage of poly(ADP-ribose) polymerase and apoptosis in dopaminergic cells: protective effect of mitochondrial anti-apoptotic protein Bcl-2.

    Science.gov (United States)

    Kitazawa, Masashi; Anantharam, Vellareddy; Kanthasamy, Arthi; Kanthasamy, Anumantha G

    2004-06-01

    Previously, we demonstrated that the organochlorine pesticide dieldrin induces mitochondrial depolarization, caspase-3 activation and apoptosis in dopaminergic PC12 cells. We also demonstrated that protein kinase Cdelta (PKCdelta), a member of a novel PKC family of proteins, is proteolytically activated by caspase-3 to mediate apoptotic cell death processes. In the present study, we have further characterized the protective effect of the major mitochondrial anti-apoptotic protein Bcl-2 against dieldrin-induced apoptotic events in dopaminergic cells. Exposure to dieldrin (30-100 microM) produced significant cytotoxicity and caspase-3 activation within 3h in vector-transfected PC12 cells, whereas human Bcl-2-transfected PC12 cells were almost completely resistant to dieldrin-induced cytotoxicity and caspase-3 activation. Also, dieldrin (30-300 microM) treatment induced proteolytic cleavage of poly(ADP-ribose) polymerase (PARP), which was blocked by pretreatment with caspase-3 inhibitors Z-DEVD-FMK and Z-VAD-FMK. Additionally, dieldrin-induced chromatin condensation and DNA fragmentation were completely blocked in Bcl-2-overexpressed PC12 cells as compared to vector control cells. Together, these results clearly indicate that overexpression of mitochondrial anti-apoptotic protein protects against dieldrin-induced apoptotic cell death and further suggest that dieldrin primarily alters mitochondrial function to initiate apoptotic cell death in dopaminergic cells.

  20. Hydrogen sulfide-mediated stimulation of mitochondrial electron transport involves inhibition of the mitochondrial phosphodiesterase 2A, elevation of cAMP and activation of protein kinase A.

    Science.gov (United States)

    Módis, Katalin; Panopoulos, Panagiotis; Coletta, Ciro; Papapetropoulos, Andreas; Szabo, Csaba

    2013-11-01

    Although hydrogen sulfide (H₂S) is generally known as a mitochondrial poison, recent studies show that lower concentrations of H₂S play a physiological role in the stimulation of mitochondrial electron transport and cellular bioenergetics. This effect involves electron donation at Complex II. Other lines of recent studies demonstrated that one of the biological actions of H₂S involves inhibition of cAMP and cGMP phosphodiesterases (PDEs). Given the emerging functional role of the mitochondrial isoform of cAMP PDE (PDE2A) in the regulation of mitochondrial function the current study investigated whether cAMP-dependent mechanisms participate in the stimulatory effect of NaHS on mitochondrial function. In isolated rat liver mitochondria, partial digestion studies localized PDE2A into the mitochondrial matrix. NaHS exerted a concentration-dependent inhibitory effect on recombinant PDE2A enzyme in vitro. Moreover, NaHS induced an elevation of cAMP levels when added to isolated mitochondria and stimulated the mitochondrial electron transport. The latter effect was inhibited by Rp-cAMP, an inhibitor of the cAMP-dependent protein kinase (PKA). The current findings suggest that the direct electron donating effect of NaHS is amplified by an intramitochondrial cAMP system, which may involve the inhibition of PDE2A and subsequent, cAMP-mediated stimulation of PKA.

  1. The deleterious effect of cholesterol and protection by quercetin on mitochondrial bioenergetics of pancreatic β-cells, glycemic control and inflammation: In vitro and in vivo studies

    Directory of Open Access Journals (Sweden)

    Catalina Carrasco-Pozo

    2016-10-01

    Full Text Available Studying rats fed high cholesterol diet and a pancreatic β-cell line (Min6, we aimed to determine the mechanisms by which quercetin protects against cholesterol-induced pancreatic β-cell dysfunction and impairments in glycemic control. Quercetin prevented the increase in total plasma cholesterol, but only partially prevented the high cholesterol diet-induced alterations in lipid profile. Quercetin prevented cholesterol-induced decreases in pancreatic ATP levels and mitochondrial bioenergetic dysfunction in Min6 cells, including decreases in mitochondrial membrane potentials and coupling efficiency in the mitochondrial respiration (basal and maximal oxygen consumption rate (OCR, ATP-linked OCR and reserve capacity. Quercetin protected against cholesterol-induced apoptosis of Min6 cells by inhibiting caspase-3 and -9 activation and cytochrome c release. Quercetin prevented the cholesterol-induced decrease in antioxidant defence enzymes from pancreas (cytosolic and mitochondrial homogenates and Min6 cells and the cholesterol-induced increase of cellular and mitochondrial oxidative status and lipid peroxidation. Quercetin counteracted the cholesterol-induced activation of the NFκB pathway in the pancreas and Min6 cells, normalizing the expression of pro-inflammatory cytokines. Quercetin inhibited the cholesterol-induced decrease in sirtuin 1 expression in the pancreas and pancreatic β-cells. Taken together, the anti-apoptotic, antioxidant and anti-inflammatory properties of quercetin, and its ability to protect and improve mitochondrial bioenergetic function are likely to contribute to its protective action against cholesterol-induced pancreatic β-cell dysfunction, thereby preserving glucose-stimulated insulin secretion (GSIS and glycemic control. Specifically, the improvement of ATP-linked OCR and the reserve capacity are important mechanisms for protection of quercetin. In addition, the inhibition of the NFκB pathway is an important

  2. Mitochondrial calcium and oxidative stress as mediators of ischemic brain injury.

    Science.gov (United States)

    Starkov, Anatoly A; Chinopoulos, Christos; Fiskum, Gary

    2004-01-01

    Acute ischemic and brain injury is triggered by excitotoxic elevation of intraneuronal Ca2+ followed by reoxygenation-dependent oxidative stress, metabolic failure, and cell death. Studies performed in vitro with neurons exposed to excitotoxic concentrations of glutamate demonstrate an initial rise in cytosolic [Ca2+], followed by a reduction to a normal, albeit slightly elevated concentration. This reduction in cytosolic [Ca2+] is due partially to active, respiration-dependent mitochondrial Ca2+ sequestration. Within minutes to an hour following the initial Ca2+ transient, most neurons undergo delayed Ca2+ deregulation characterized by a dramatic rise in cytosolic Ca2+. This prelethal secondary rise in Ca2+ is due to influx across the plasma membrane but is dependent on the initial mitochondrial Ca2+ uptake and associated oxidative stress. Mitochondrial Ca2+ uptake can stimulate the net production of reactive oxygen species (ROS) through activation of the membrane permeability transition, release of cytochrome c, respiratory inhibition, release of pyridine nucleotides, and loss of intramitochondrial glutathione necessary for detoxification of peroxides. Targets of mitochondrially derived ROS may include plasma membrane Ca2+ channels that mediate excitotoxic delayed Ca2+ deregulation.

  3. Parkia biglobosa Improves Mitochondrial Functioning and Protects against Neurotoxic Agents in Rat Brain Hippocampal Slices

    Directory of Open Access Journals (Sweden)

    Kayode Komolafe

    2014-01-01

    Full Text Available Objective. Methanolic leaf extracts of Parkia biglobosa, PBE, and one of its major polyphenolic constituents, catechin, were investigated for their protective effects against neurotoxicity induced by different agents on rat brain hippocampal slices and isolated mitochondria. Methods. Hippocampal slices were preincubated with PBE (25, 50, 100, or 200 µg/mL or catechin (1, 5, or 10 µg/mL for 30 min followed by further incubation with 300 µM H2O2, 300 µM SNP, or 200 µM PbCl2 for 1 h. Effects of PBE and catechin on SNP- or CaCl2-induced brain mitochondrial ROS formation and mitochondrial membrane potential (ΔΨm were also determined. Results. PBE and catechin decreased basal ROS generation in slices and blunted the prooxidant effects of neurotoxicants on membrane lipid peroxidation and nonprotein thiol contents. PBE rescued hippocampal cellular viability from SNP damage and caused a significant boost in hippocampus Na+, K+-ATPase activity but with no effect on the acetylcholinesterase activity. Both PBE and catechin also mitigated SNP- or CaCl2-dependent mitochondrial ROS generation. Measurement by safranine fluorescence however showed that the mild depolarization of the ΔΨm by PBE was independent of catechin. Conclusion. The results suggest that the neuroprotective effect of PBE is dependent on its constituent antioxidants and mild mitochondrial depolarization propensity.

  4. Protective effects of rilmenidine and AGN 192403 on oxidative cytotoxicity and mitochondrial inhibitor-induced cytotoxicity in astrocytes.

    Science.gov (United States)

    Choi, Dong-Hee; Kim, Dong-Hoon; Park, Yun-Gyu; Chun, Boe-Gwun; Choi, Sang-Hyun

    2002-11-15

    Oxidative stress and mitochondrial dysfunction are important aspects of pathogenesis, particularly in the brain, which is highly dependent on oxygen, and the protection of astrocytes is essential for neuroprotection. In this context, imidazoline drugs have been reported to be neuroprotective. Our recent study showed that imidazoline drugs, including guanabenz, inhibit the naphthazarin-induced oxidative cytotoxicity associated with lysosomal destabilization. We now report on a study into the protective effects of rilmenidine and AGN 192403, which have affinity for imidazoline-1 receptors, on the cytotoxicity induced by naphthazarin and inhibitors of mitochondrial respiration in astrocytes. Cytotoxicity was measured grossly by LDH release and by measuring changes in lysosomal membrane stability and features of mitochondrial membrane permeabilization. Naphthazarin-induced cytotoxicity was evidenced by the ordered development of lysosomal acridine orange relocation, decrease in mitochondrial potential, cytochrome c release, and caspase-9 activation, and was inhibited by guanabenz, rilmenidine, and AGN 192403. Antimycin A and rotenone induced mitochondrial dysfunction primarily, and their cytotoxicities were inhibited only by AGN 192403. Rilmenidine and guanabenz may have a lysosomal stabilizing effect, which underlies their protective effects. AGN 192403 might affect the mitochondrial cell death cascades, and had a novel protective effect on the cytotoxicity associated with mitochondrial dysfunction.

  5. Phellinus linteus mushroom protects against tacrine-induced mitochondrial impairment and oxidative stress in HepG2 cells.

    Science.gov (United States)

    Gao, Chunpeng; Zhong, Laifu; Jiang, Liping; Geng, Chengyan; Yao, Xiaofeng; Cao, Jun

    2013-06-15

    Tacrine (THA) was the first drug licensed for the treatment of Alzheimer's disease. Unfortunately, reversible hepatotoxicity is evident in about 30% of patients and limits its clinical use. The intracellular mechanisms have not yet been elucidated. Phellinus linteus (PL) is a mushroom that has long been used as a folk medicine. In our previous study, we found that PL could decrease the reactive oxygen species (ROS) formation in HepG2 cells. Presently, protective effects of PL on tacrine-induced ROS formation and mitochondria dysfunction were evaluated. The results showed that PL significantly reduced tacrine-induced ROS production, disruption of ΔΨm, 8-OHdG formation in mitochondrial DNA, and cytotoxicity in HepG2 cells. These data suggest that PL could attenuate the cytotoxicity and mitochondria dysfunction induced by tacrine in HepG2 cells. The protection is probably mediated by an antioxidant protective mechanism. Consumption of PL may be a plausible way to prevent tacrine-induced hepatotoxicity.

  6. Loss of mitochondrial exo/endonuclease EXOG affects mitochondrial respiration and induces ROS-mediated cardiomyocyte hypertrophy.

    Science.gov (United States)

    Tigchelaar, Wardit; Yu, Hongjuan; de Jong, Anne Margreet; van Gilst, Wiek H; van der Harst, Pim; Westenbrink, B Daan; de Boer, Rudolf A; Silljé, Herman H W

    2015-01-15

    Recently, a locus at the mitochondrial exo/endonuclease EXOG gene, which has been implicated in mitochondrial DNA repair, was associated with cardiac function. The function of EXOG in cardiomyocytes is still elusive. Here we investigated the role of EXOG in mitochondrial function and hypertrophy in cardiomyocytes. Depletion of EXOG in primary neonatal rat ventricular cardiomyocytes (NRVCs) induced a marked increase in cardiomyocyte hypertrophy. Depletion of EXOG, however, did not result in loss of mitochondrial DNA integrity. Although EXOG depletion did not induce fetal gene expression and common hypertrophy pathways were not activated, a clear increase in ribosomal S6 phosphorylation was observed, which readily explains increased protein synthesis. With the use of a Seahorse flux analyzer, it was shown that the mitochondrial oxidative consumption rate (OCR) was increased 2.4-fold in EXOG-depleted NRVCs. Moreover, ATP-linked OCR was 5.2-fold higher. This increase was not explained by mitochondrial biogenesis or alterations in mitochondrial membrane potential. Western blotting confirmed normal levels of the oxidative phosphorylation (OXPHOS) complexes. The increased OCR was accompanied by a 5.4-fold increase in mitochondrial ROS levels. These increased ROS levels could be normalized with specific mitochondrial ROS scavengers (MitoTEMPO, mnSOD). Remarkably, scavenging of excess ROS strongly attenuated the hypertrophic response. In conclusion, loss of EXOG affects normal mitochondrial function resulting in increased mitochondrial respiration, excess ROS production, and cardiomyocyte hypertrophy. Copyright © 2015 the American Physiological Society.

  7. Sodium butyrate induces DRP1-mediated mitochondrial fusion and apoptosis in human colorectal cancer cells.

    Science.gov (United States)

    Tailor, Dhanir; Hahm, Eun-Ryeong; Kale, Raosaheb K; Singh, Shivendra V; Singh, Rana P

    2014-05-01

    Sodium butyrate (NaBt) is the byproduct of anaerobic microbial fermentation inside the gastro-intestinal tract that could reach up to 20mM, and has been shown to inhibit the growth of various cancers. Herein, we evaluated its effect on mitochondrial fusion and associated induction of apoptosis in colorectal cancer cells (CRC). NaBt treatment at physiological (1-5mM) concentrations for 12 and 24h decreased the cell viability and induced G2-M phase cell cycle arrest in HCT116 (12h) and SW480 human CRC cells. This cell cycle arrest was associated with mitochondria-mediated apoptosis accompanied by a decrease in survivin and Bcl-2 expression, and generation of reactive oxygen species (ROS). Furthermore, NaBt treatment resulted in a significant decrease in the mitochondrial mass which is an indicator of mitochondrial fusion. Level of dynamin-related protein 1 (DRP1), a key regulator of mitochondrial fission and fusion where its up-regulation correlates with fission, was found to be decreased in CRC cells. Further, at early treatment time, DRP1 down-regulation was noticed in mitochondria which later became drastically reduced in both mitochondria as well as cytosol. DRP1 is activated by cyclin B1-CDK1 complex by its ser616 phosphorylation in which both cyclin B1-CDK1 complex and phospho-DRP1 (ser616) were strongly reduced by NaBt treatment. DRP1 was observed to be regulated by apoptosis as pan-caspase inhibitor showing rescue from NaBt-induced apoptosis also caused the reversal of DRP1 to the normal level as in control proliferating cells. Together, these findings suggest that NaBt can modulate mitochondrial fission and fusion by regulating the level of DRP1 and induce cell cycle arrest and apoptosis in human CRC cells.

  8. Changes in mitochondrial morphology induced by calcium or rotenone in primary astrocytes occur predominantly through ros-mediated remodeling.

    Science.gov (United States)

    Deheshi, Samineh; Dabiri, Bahram; Fan, Susu; Tsang, Michelle; Rintoul, Gordon L

    2015-06-01

    Morphological changes in mitochondria have been primarily attributed to fission and fusion, while the more pliable transformations of mitochondria (remodeling, rounding, or stretching) have been largely overlooked. In this study, we quantify the contributions of fission and remodeling to changes in mitochondrial morphology induced by the Ca(2+) ionophore 4Br-A23187 and the metabolic toxin rotenone. We also examine the role of reactive oxygen species (ROS) in the regulation of mitochondrial remodeling. In agreement with our previous studies, mitochondrial remodeling, not fission, is the primary contributor to Ca(2+) -mediated changes in mitochondrial morphology induced by 4Br-A23187 in rat cortical astrocytes. Treatment with rotenone produced similar results. In both paradigms, remodeling was selectively blocked by antioxidants whereas fission was not, suggesting a ROS-mediated mechanism for mitochondrial remodeling. In support of this hypothesis, inhibition of endogenous ROS by overnight incubation in antioxidants resulted in elongated reticular networks of mitochondria. Examination of inner and outer mitochondrial membranes revealed that they largely acted in concert during the remodeling process. While mitochondrial morphology is traditionally ascribed to a net output of fission and fusion processes, in this study we provide evidence that the acute pliability of mitochondria can be a dominant factor in determining their morphology. More importantly, our results suggest that the remodeling process is independently regulated through a ROS-signaling mechanism. Mitochondrial morphology is traditionally ascribed to a balance of fission and fusion processes. We have shown that mitochondria can undergo more pliable transformations; remodeling, rounding, or stretching. We demonstrate that remodeling, not fission, is the primary contributor to calcium mediated changes in mitochondrial morphology in primary astrocytes. Others have shown fission is mediated by calcineurin

  9. DLP1-Dependent Mitochondrial Fragmentation Mediates 1-methyl-4-phenylpyridinium Toxicity in Neurons: Implications for Parkinson's Disease

    Science.gov (United States)

    Wang, Xinglong; Su, Bo; Liu, Wanhong; He, Xiaohua; Gao, Yuan; Castellani, Rudy J.; Perry, George; Smith, Mark A.; Zhu, Xiongwei

    2011-01-01

    SUMMARY Selective degeneration of nigrostriatal dopaminergic neurons in Parkinson disease (PD) can be modeled by the administration of the neurotoxin 1-methyl-4-phenylpyridinium (MPP+). Since abnormal mitochondrial dynamics are increasingly implicated in the pathogenesis of PD, in this study, we investigated the effect of MPP+ on mitochondrial dynamics and assessed temporal and causal relationship with other toxic effects induced by MPP+ in neuronal cells. In SH-SY5Y cells, MPP+ causes a rapid increase in mitochondrial fragmentation followed by a second wave of increase in mitochondrial fragmentation, along with increased DLP1 expression and mitochondrial translocation. Genetic inactivation of DLP1 completely blocks MPP+-induced mitochondrial fragmentation. Notably, this approach partially rescues MPP+-induced decline in ATP levels and ATP/ADP ratio and increased [Ca2+]i and almost completely prevents increased reactive oxygen species production, loss of mitochondrial membrane potential, enhanced autophagy and cell death, suggesting that mitochondria fragmentation is an upstream event that mediates MPP+-induced toxicity. On the other hand, thiol antioxidant NAC or glutamate receptor antagonist D-AP5 also partially alleviate MPP+-induced mitochondrial fragmentation, suggesting a vicious spiral of events contributes to MPP+-induced toxicity. We further validated our findings in primary rat midbrain dopaminergic neurons that 0.5 μM MPP+ induced mitochondrial fragmentation only in TH-positive dopaminergic neurons in a similar pattern to that in SH-SY5Y cells but had no effects on these mitochondrial parameters in TH-negative neurons. Overall, these findings suggest that DLP1-dependent mitochondrial fragmentation plays a crucial role in mediating MPP+-induced mitochondria abnormalities and cellular dysfunction and may represent a novel therapeutic target for PD. PMID:21615675

  10. Thrombopoietin Protects Cardiomyocytes from Iron-Overload Induced Oxidative Stress and Mitochondrial Injury

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    Shing Chan

    2015-07-01

    Full Text Available Background/Aims: Thalassaemia accompanied with iron-overload is common in Hong Kong. Iron-overload induced cardiomyopathy is the commonest cause of morbidity and mortality in patients with β-thalassaemia. Chronic iron-overload due to blood transfusion can cause cardiac failure. Decreased antioxidant defence and increased ROS production may lead to oxidative stress and cell injury. Iron-overload may lead to heart tissue damage through lipid peroxidation in response to oxidative stress, and a great diversity of toxic aldehydes are formed when lipid hydroperoxides break down in heart and plasma. Methods: Iron entry into embryonic heart H9C2 cells was determined by calcein assay using a fluorometer. Reactive oxygen species (ROS production in cells treated with FeCl3 or thrombopoietin (TPO was monitored by using the fluorescent probe H2DCFDA. Changes in mitochondrial membrane potential of H9C2 cells were quantified by using flow cytometry. Results: We demonstrated that iron induced oxidative stress and apoptosis in cardiomyocytes, and that iron increased ROS production and reduced cell viability in a dose-dependent manner. Iron treatment increased the proportion of cells with JC-1 monomers, indicating a trend of drop in the mitochondrial membrane potential. TPO exerted a cardio-protective effect on iron-induced apoptosis. Conclusions: These findings suggest that iron-overload leads to the generation of ROS and further induces apoptosis in cardiomyocytes via mitochondrial pathways. TPO might exert a protective effect on iron-overload induced apoptosis via inhibiting oxidative stress and suppressing the mitochondrial pathways in cardiomyocytes.

  11. Protective effects of pinacidil hyperpolarizing cardioplegia on myocardial ischemia reperfusion injury by mitochondrial KATP channels

    Institute of Scientific and Technical Information of China (English)

    YU Tian; FU Xiao-yun; LIU Xing-kui; YU Zhi-hao

    2011-01-01

    Background Many studies have indicated that hyperpolarizing cardioplegia is responsible for myocardial preservation and researchers have suggested that the adenosine triphosphate-sensitive potassium channels (KATP) were the end effectors of cardio-protection.But whether mitochondrial KATP plays an important role in hyperpolarizing cardioplegia is not apparent.The present study investigated the effect of hyperpolarizing cardioplegia containing pinacidil (a nonselective KATP opener) on ischemia/reperfusion injury in rat hearts,especially the role of mitochondrial KATP in pinacidil hyperpolarizing cardioplegia.Methods Sprague-Dawley rat hearts were Langendorff-perfused for 20 minutes with Krebs-Henseleit buffer at 37℃before equilibration.Cardiac arrest was then induced in different treatments:there was no arrest and ischemia in the normal group,the control group were arrested by clamping the aorta,depolarizing caidioplegia (St.Thomas solution containing 16 mmol/L KCI) and hyperpolarizing cardioplegia groups used St.Thomas solution containing 0.05 mmol/L pinacidil and 5 mmol/L KCI to induce cardiac arrest in group hyperkalemic and group pinacidil,in group hyperkalemic + 5-hydroxydecanote (5HD) and Pinacidil + 5HD,5HD (0.1 mmol/L) was added to the above two solutions to block mitochondria KATP channels.Global ischemia was then administrated for 40 minutes at 37℃,followed by 30 minutes of reperfusion.At the end of equilibration and reperfusion,hemodynamics,ultrastructure,and mitochondrial function were measured.Results In the control group,ischemia/reperfusion decreased the left ventricular developed pressure,heart rate,coronary flow,mitochondrial membrane potential,impaired mitochondrial respiratory function,increased reactive oxygen species and left ventricular end diastolic pressure.Damage to myocardial ultrastructure was also evident.Both depolarized arrest and especially hyperpolarized cardioplegia significantly reduced these lesions.5HD partially blocked the

  12. Over-expressed copper/zinc superoxide dismutase localizes to mitochondria in neurons inhibiting the angiotensin II-mediated increase in mitochondrial superoxide.

    Science.gov (United States)

    Li, Shumin; Case, Adam J; Yang, Rui-Fang; Schultz, Harold D; Zimmerman, Matthew C

    2013-01-01

    Angiotensin II (AngII) is the main effector peptide of the renin-angiotensin system (RAS), and contributes to the pathogenesis of cardiovascular disease by exerting its effects on an array of different cell types, including central neurons. AngII intra-neuronal signaling is mediated, at least in part, by reactive oxygen species, particularly superoxide (O2 (•-)). Recently, it has been discovered that mitochondria are a major subcellular source of AngII-induced O2 (•-). We have previously reported that over-expression of manganese superoxide dismutase (MnSOD), a mitochondrial matrix-localized O2 (•-) scavenging enzyme, inhibits AngII intra-neuronal signaling. Interestingly, over-expression of copper/zinc superoxide dismutase (CuZnSOD), which is believed to be primarily localized to the cytoplasm, similarly inhibits AngII intra-neuronal signaling and provides protection against AngII-mediated neurogenic hypertension. Herein, we tested the hypothesis that CuZnSOD over-expression in central neurons localizes to mitochondria and inhibits AngII intra-neuronal signaling by scavenging mitochondrial O2 (•-). Using a neuronal cell culture model (CATH.a neurons), we demonstrate that both endogenous and adenovirus-mediated over-expressed CuZnSOD (AdCuZnSOD) are present in mitochondria. Furthermore, we show that over-expression of CuZnSOD attenuates the AngII-mediated increase in mitochondrial O2 (•-) levels and the AngII-induced inhibition of neuronal potassium current. Taken together, these data clearly show that over-expressed CuZnSOD in neurons localizes in mitochondria, scavenges AngII-induced mitochondrial O2 (•-), and inhibits AngII intra-neuronal signaling.

  13. Over-expressed copper/zinc superoxide dismutase localizes to mitochondria in neurons inhibiting the angiotensin II-mediated increase in mitochondrial superoxide

    Directory of Open Access Journals (Sweden)

    Shumin Li

    2014-01-01

    Full Text Available Angiotensin II (AngII is the main effector peptide of the renin–angiotensin system (RAS, and contributes to the pathogenesis of cardiovascular disease by exerting its effects on an array of different cell types, including central neurons. AngII intra-neuronal signaling is mediated, at least in part, by reactive oxygen species, particularly superoxide (O2·−. Recently, it has been discovered that mitochondria are a major subcellular source of AngII-induced O2·−. We have previously reported that over-expression of manganese superoxide dismutase (MnSOD, a mitochondrial matrix-localized O2·− scavenging enzyme, inhibits AngII intra-neuronal signaling. Interestingly, over-expression of copper/zinc superoxide dismutase (CuZnSOD, which is believed to be primarily localized to the cytoplasm, similarly inhibits AngII intra-neuronal signaling and provides protection against AngII-mediated neurogenic hypertension. Herein, we tested the hypothesis that CuZnSOD over-expression in central neurons localizes to mitochondria and inhibits AngII intra-neuronal signaling by scavenging mitochondrial O2·−. Using a neuronal cell culture model (CATH.a neurons, we demonstrate that both endogenous and adenovirus-mediated over-expressed CuZnSOD (AdCuZnSOD are present in mitochondria. Furthermore, we show that over-expression of CuZnSOD attenuates the AngII-mediated increase in mitochondrial O2·− levels and the AngII-induced inhibition of neuronal potassium current. Taken together, these data clearly show that over-expressed CuZnSOD in neurons localizes in mitochondria, scavenges AngII-induced mitochondrial O2·−, and inhibits AngII intra-neuronal signaling.

  14. Small Molecules that Protect Mitochondrial Function from Metabolic Stress Decelerate Loss of Photoreceptor Cells in Murine Retinal Degeneration Models.

    Science.gov (United States)

    Beeson, Craig; Lindsey, Chris; Nasarre, Cecile; Bandyopadhyay, Mausumi; Perron, Nathan; Rohrer, Bärbel

    2016-01-01

    One feature common to many of the pathways implicated in retinal degeneration is increased metabolic stress leading to impaired mitochondrial function. We found that exposure of cells to calcium ionophores or oxidants as metabolic stressors diminish maximal mitochondrial capacity. A library of 50,000 structurally diverse "drug-like" molecules was screened for protection against loss of calcium-induced loss of mitochondrial capacity in 661W rod-derived cells and C6 glioblastomas. Initial protective hits were then tested for protection against IBMX-induced loss of mitochondrial capacity as measured via respirometry. Molecules that protected mitochondria were then evaluated for protection of rod photoreceptor cells in retinal explants from rd1 mice. Two of the molecules attenuated loss of photoreceptor cells in the rd1 model. In the 661W cells, exposure to calcium ionophore or tert-butylhydroperoxide caused mitochondrial fragmentation that was blocked with the both compounds. Our studies have identified molecules that protect mitochondria and attenuate loss of photoreceptors in models of retinal degeneration suggesting that they could be good leads for development of therapeutic drugs for treatment of a wide variety of retinal dystrophies.

  15. L-carnitine protects C2C12 cells against mitochondrial superoxide overproduction and cell death

    Science.gov (United States)

    Le Borgne, Françoise; Ravaut, Gaétan; Bernard, Arnaud; Demarquoy, Jean

    2017-01-01

    AIM To identify and characterize the protective effect that L-carnitine exerted against an oxidative stress in C2C12 cells. METHODS Myoblastic C2C12 cells were treated with menadione, a vitamin K analog that engenders oxidative stress, and the protective effect of L-carnitine (a nutrient involved in fatty acid metabolism and the control of the oxidative process), was assessed by monitoring various parameters related to the oxidative stress, autophagy and cell death. RESULTS Associated with its physiological function, a muscle cell metabolism is highly dependent on oxygen and may produce reactive oxygen species (ROS), especially under pathological conditions. High levels of ROS are known to induce injuries in cell structure as they interact at many levels in cell function. In C2C12 cells, a treatment with menadione induced a loss of transmembrane mitochondrial potential, an increase in mitochondrial production of ROS; it also induces autophagy and was able to provoke cell death. Pre-treatment of the cells with L-carnitine reduced ROS production, diminished autophagy and protected C2C12 cells against menadione-induced deleterious effects. CONCLUSION In conclusion, L-carnitine limits the oxidative stress in these cells and prevents cell death.

  16. Mitochondrial Protection and Anti-aging Activity of Astragalus Polysaccharides and Their Potential Mechanism

    Directory of Open Access Journals (Sweden)

    Xiao-Juan Xin

    2012-02-01

    Full Text Available The current study was performed to investigate mitochondrial protection and anti-aging activity of Astragalus polysaccharides (APS and the potential underlying mechanism. Lipid peroxidation of liver and brain mitochondria was induced by Fe2+–Vit C in vitro. Thiobarbituric acid (TBA colorimetry was used to measure the content of thiobarbituric acid reactive substances (TBARS. Mouse liver mitochondrial permeability transition (PT was induced by calcium overload in vitro and spectrophotometry was used to measure it. The scavenging activities of APS on superoxide anion (O2•- and hydroxyl radical (•OH, which were produced by reduced nicotinamide adenine dinucleotide (NADH—N-Methylphenazonium methyl sulfate (PMS and hydrogen peroxide (H2O2–Fe2+ system respectively, were measured by 4-nitrobluetetrazolium chloride (NBT reduction and Fenton reaction colorimetry respectively. The Na2S2O3 titration method was used to measure the scavenging activities of APS on H2O2. APS could inhibit TBARS production, protect mitochondria from PT, and scavenge O2•-, •OH and H2O2 significantly in a concentration-dependent manner respectively. The back of the neck of mice was injected subcutaneously with D-galactose to induce aging at a dose of 100 mg/kg/d for seven weeks. Moreover, the activities of catalase (CAT, surperoxide dismutase (SOD and glutathione peroxidase (GPx and anti-hydroxyl radical which were assayed by using commercial monitoring kits were increased significantly in vivo by APS. According to this research, APS protects mitochondria by scavenging reactive oxygen species (ROS, inhibiting mitochondrial PT and increasing the activities of antioxidases. Therefore, APS has the effect of promoting health.

  17. Synaptic activity protects neurons against calcium-mediated oxidation and contraction of mitochondria during excitotoxicity.

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    Depp, Constanze; Bas-Orth, Carlos; Schroeder, Lisa; Hellwig, Andrea; Bading, Hilmar

    2017-10-07

    Excitotoxicity triggered by extrasynaptic N-methyl-D-aspartate-type glutamate receptors (NMDARs) has been implicated in many neurodegenerative conditions, including Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, and stroke. Mitochondrial calcium overload leading to mitochondrial dysfunction represents an early event in excitotoxicity. Neurons are rendered resistant to excitotoxicity by previous periods of synaptic activity that activates a nuclear calcium-driven neuroprotective gene program. This process, termed acquired neuroprotection, involves transcriptional repression of the mitochondrial calcium uniporter leading to a reduction in excitotoxcity-associated mitochondrial calcium load. As mitochondrial calcium and the production of reactive oxygen species (ROS) may be linked, we monitored excitotoxicity-associated changes in the mitochondrial redox status using the ratiometric glutathione redox potential indicator, Grx1-roGFP2, targeted to the mitochondrial matrix. Aim of this study was to investigate if suppression of oxidative stress underlies mitoprotection afforded by synaptic activity. We found that synaptic activity protects primary rat hippocampal neurons against acute excitotoxicity-induced mitochondrial oxidative stress and mitochondrial contraction associated with it. Downregulation of the mitochondrial uniporter by genetic means mimics the protective effect of synaptic activity on mitochondrial redox status. These findings indicate that oxidative stress acts downstream of mitochondrial calcium overload in excitotoxicity. Innovation and conclusion: We established mito-Grx1-roGFP2 as a reliable and sensitive tool to monitor rapid redox changes in mitochondria during excitotoxicity. Our results highlight the importance of developing means of blocking mitochondrial calcium overload for therapeutic targeting of oxidative stress and mitochondrial dysfunction in neurodegenerative diseases.

  18. Engrailed protects mouse midbrain dopaminergic neurons against mitochondrial complex I insults

    OpenAIRE

    Alvarez-Fischer, Daniel; Fuchs, Julia; Castagner, François; Stettler, Olivier; Massiani-Beaudoin, Olivia; Moya, Kenneth L.; Bouillot, Colette; Oertel, Wolfgang H; Lombès, Anne; Faigle, Wolfgang; Joshi, Rajiv L.; HARTMANN, Andreas; Prochiantz, Alain

    2011-01-01

    Abstract Mice heterozygous for homeobox gene Engrailed-1 display progressive loss of mesencephalic dopaminergic (mDA) neurons. We report that exogenous Engrailed-1 and Engrailed-2 (collectively Engrailed) protect mDA neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mitochondrial complex I toxin used to model PD in animals. Engrailed enhances the translation of nuclear-encoded mRNAs for two key complex I subunits, Ndufs1 and Ndufs3, and increases complex I activit...

  19. Astaxanthin prevents pulmonary fibrosis by promoting myofibroblast apoptosis dependent on Drp1-mediated mitochondrial fission.

    Science.gov (United States)

    Zhang, Jinjin; Xu, Pan; Wang, Youlei; Wang, Meirong; Li, Hongbo; Lin, Shengcui; Mao, Cuiping; Wang, Bingsi; Song, Xiaodong; Lv, Changjun

    2015-09-01

    Promotion of myofibroblast apoptosis is a potential therapeutic strategy for pulmonary fibrosis. This study investigated the antifibrotic effect of astaxanthin on the promotion of myofibroblast apoptosis based on dynamin-related protein-1 (Drp1)-mediated mitochondrial fission in vivo and in vitro. Results showed that astaxanthin can inhibit lung parenchymal distortion and collagen deposition, as well as promote myofibroblast apoptosis. Astaxanthin demonstrated pro-apoptotic function in myofibroblasts by contributing to mitochondrial fission, thereby leading to apoptosis by increasing the Drp1 expression and enhancing Drp1 translocation into the mitochondria. Two specific siRNAs were used to demonstrate that Drp1 is necessary to promote astaxanthin-induced mitochondrial fission and apoptosis in myofibroblasts. Drp1-associated genes, such as Bcl-2-associated X protein, cytochrome c, tumour suppressor gene p53 and p53-up-regulated modulator of apoptosis, were highly up-regulated in the astaxanthin group compared with those in the sham group. This study revealed that astaxanthin can prevent pulmonary fibrosis by promoting myofibroblast apoptosis through a Drp1-dependent molecular pathway. Furthermore, astaxanthin provides a potential therapeutic value in pulmonary fibrosis treatment.

  20. Mitochondrial Ca2+ cycle mediated by the palmitate-activated cyclosporin A-insensitive pore.

    Science.gov (United States)

    Mironova, Galina D; Belosludtsev, Konstantin N; Belosludtseva, Natalia V; Gritsenko, Elena N; Khodorov, Boris I; Saris, Nils-Erik L

    2007-04-01

    Earlier we found that in isolated rat liver mitochondria the reversible opening of the mitochondrial cyclosporin A-insensitive pore induced by low concentrations of palmitic acid (Pal) plus Ca(2+) results in the brief loss of Deltapsi [Mironova et al., J Bioenerg Biomembr (2004), 36:171-178]. Now we report that Pal and Ca(2+), increased to 30 and 70 nmol/mg protein respectively, induce a stable and prolonged (10 min) partial depolarization of the mitochondrial membrane, the release of Ca(2+) and the swelling of mitochondria. Inhibitors of the Ca(2+) uniporter, ruthenium red and La(3+), as well as EGTA added in 10 min after the Pal/Ca(2+)-activated pore opening, prevent the release of Ca(2+) and repolarize the membrane to initial level. Similar effects can be observed in the absence of exogeneous Pal, upon mitochondria accumulating high [Sr(2+)], which leads to the activation of phospholipase A(2) and appearance of endogenous fatty acids. The paper proposes a new model of the mitochondrial Ca(2+) cycle, in which Ca(2+) uptake is mediated by the Ca(2+) uniporter and Ca(2+) efflux occurs via a short-living Pal/Ca(2+)-activated pore.

  1. Protective Action of Neurotrophic Factors and Estrogen against Oxidative Stress-Mediated Neurodegeneration

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    Tadahiro Numakawa

    2011-01-01

    Full Text Available Oxidative stress is involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Low levels of reactive oxygen species (ROS and reactive nitrogen species (RNS are important for maintenance of neuronal function, though elevated levels lead to neuronal cell death. A complex series of events including excitotoxicity, Ca2+ overload, and mitochondrial dysfunction contributes to oxidative stress-mediated neurodegeneration. As expected, many antioxidants like phytochemicals and vitamins are known to reduce oxidative toxicity. Additionally, growing evidence indicates that neurotrophic factors such as brain-derived neurotrophic factor (BDNF and estrogens significantly prevent neuronal damage caused by oxidative stress. Here, we review and discuss recent studies addressing the protective mechanisms of neurotrophic factors and estrogen within this system.

  2. VEZF1 elements mediate protection from DNA methylation.

    Directory of Open Access Journals (Sweden)

    Jacqueline Dickson

    2010-01-01

    Full Text Available There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm beta-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin state.

  3. Selective Inhibition of the Mitochondrial Permeability Transition Pore Protects against Neurodegeneration in Experimental Multiple Sclerosis*

    Science.gov (United States)

    Warne, Justin; Pryce, Gareth; Hill, Julia M.; Shi, Xiao; Lennerås, Felicia; Puentes, Fabiola; Kip, Maarten; Hilditch, Laura; Walker, Paul; Simone, Michela I.; Chan, A. W. Edith; Towers, Greg J.; Coker, Alun R.; Duchen, Michael R.; Szabadkai, Gyorgy; Baker, David; Selwood, David L.

    2016-01-01

    The mitochondrial permeability transition pore is a recognized drug target for neurodegenerative conditions such as multiple sclerosis and for ischemia-reperfusion injury in the brain and heart. The peptidylprolyl isomerase, cyclophilin D (CypD, PPIF), is a positive regulator of the pore, and genetic down-regulation or knock-out improves outcomes in disease models. Current inhibitors of peptidylprolyl isomerases show no selectivity between the tightly conserved cyclophilin paralogs and exhibit significant off-target effects, immunosuppression, and toxicity. We therefore designed and synthesized a new mitochondrially targeted CypD inhibitor, JW47, using a quinolinium cation tethered to cyclosporine. X-ray analysis was used to validate the design concept, and biological evaluation revealed selective cellular inhibition of CypD and the permeability transition pore with reduced cellular toxicity compared with cyclosporine. In an experimental autoimmune encephalomyelitis disease model of neurodegeneration in multiple sclerosis, JW47 demonstrated significant protection of axons and improved motor assessments with minimal immunosuppression. These findings suggest that selective CypD inhibition may represent a viable therapeutic strategy for MS and identify quinolinium as a mitochondrial targeting group for in vivo use. PMID:26679998

  4. Selective Inhibition of the Mitochondrial Permeability Transition Pore Protects against Neurodegeneration in Experimental Multiple Sclerosis.

    Science.gov (United States)

    Warne, Justin; Pryce, Gareth; Hill, Julia M; Shi, Xiao; Lennerås, Felicia; Puentes, Fabiola; Kip, Maarten; Hilditch, Laura; Walker, Paul; Simone, Michela I; Chan, A W Edith; Towers, Greg J; Coker, Alun R; Duchen, Michael R; Szabadkai, Gyorgy; Baker, David; Selwood, David L

    2016-02-26

    The mitochondrial permeability transition pore is a recognized drug target for neurodegenerative conditions such as multiple sclerosis and for ischemia-reperfusion injury in the brain and heart. The peptidylprolyl isomerase, cyclophilin D (CypD, PPIF), is a positive regulator of the pore, and genetic down-regulation or knock-out improves outcomes in disease models. Current inhibitors of peptidylprolyl isomerases show no selectivity between the tightly conserved cyclophilin paralogs and exhibit significant off-target effects, immunosuppression, and toxicity. We therefore designed and synthesized a new mitochondrially targeted CypD inhibitor, JW47, using a quinolinium cation tethered to cyclosporine. X-ray analysis was used to validate the design concept, and biological evaluation revealed selective cellular inhibition of CypD and the permeability transition pore with reduced cellular toxicity compared with cyclosporine. In an experimental autoimmune encephalomyelitis disease model of neurodegeneration in multiple sclerosis, JW47 demonstrated significant protection of axons and improved motor assessments with minimal immunosuppression. These findings suggest that selective CypD inhibition may represent a viable therapeutic strategy for MS and identify quinolinium as a mitochondrial targeting group for in vivo use.

  5. Exercise-induced protection against reperfusion arrhythmia involves stabilization of mitochondrial energetics.

    Science.gov (United States)

    Alleman, Rick J; Tsang, Alvin M; Ryan, Terence E; Patteson, Daniel J; McClung, Joseph M; Spangenburg, Espen E; Shaikh, Saame Raza; Neufer, P Darrell; Brown, David A

    2016-05-15

    Mitochondria influence cardiac electrophysiology through energy- and redox-sensitive ion channels in the sarcolemma, with the collapse of energetics believed to be centrally involved in arrhythmogenesis. This study was conducted to determine if preservation of mitochondrial membrane potential (ΔΨm) contributes to the antiarrhythmic effect of exercise. We utilized perfused hearts, isolated myocytes, and isolated mitochondria exposed to metabolic challenge to determine the effects of exercise on cardiac mitochondria. Hearts from sedentary (Sed) and exercised (Ex; 10 days of treadmill running) Sprague-Dawley rats were perfused on a two-photon microscope stage for simultaneous measurement of ΔΨm and ECG. After ischemia-reperfusion, the collapse of ΔΨm was commensurate with the onset of arrhythmia. Exercise preserved ΔΨm and decreased the incidence of fibrillation/tachycardia (P < 0.05). Our findings in intact hearts were corroborated in isolated myocytes exposed to in vitro hypoxia-reoxygenation, with Ex rats demonstrating enhanced redox control and sustained ΔΨm during reoxygenation. Finally, we induced anoxia-reoxygenation in isolated mitochondria using high-resolution respirometry with simultaneous measurement of respiration and H2O2 Mitochondria from Ex rats sustained respiration with lower rates of H2O2 emission than Sed rats. Exercise helps sustain postischemic mitochondrial bioenergetics and redox homeostasis, which is associated with preserved ΔΨm and protection against reperfusion arrhythmia. The reduction of fatal ventricular arrhythmias through exercise-induced mitochondrial adaptations indicates that mitochondrial therapeutics may be an effective target for the treatment of heart disease. Copyright © 2016 the American Physiological Society.

  6. Calcium-Mediated Mitochondrial Permeability Transition Involved in Hydrogen Peroxide-Induced Apoptosis in Tobacco Protoplasts

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the present study, we focused on whether intracellular free Ca2+ ([Ca2+]i) regulates the formation of mitochondrial permeability transition pore (MPTP) in H2O2-induced apoptosis in tobacco protoplasts. It was shown that the decrease in mitochondrial membrane potential (△Ψm) preceded the appearance of H2O2-induced apoptosis;pretreatment with the specific MPTP inhibitor cyclosporine A, which also inhibits Ca2+ cycling by the mitochondria,effectively retarded apoptosis and the decrease in △Ψm. Apoptosis and decreased △Ψm were exacerbated by CaCl2, whereas the plasma membrane voltage-dependent Ca2+ channel blocker lanthanum chloride (LaCl3)attentuated these responses. Chelation of extracellular Ca2+ with EGTA almost totally inhibited apoptosis and the decrease in △Ψm induced by H2O2. The time-course of changes in [Ca2+]i in apoptosis was detected using the Ca2+ probe Fluo-3 AM. These studies showed that [Ca2+]i was increased at the very early stage of H2O2-induced apoptosis. The EGTA evidently inhibited the increase in [Ca2+]i induced by H2O2, whereas it was only partially inhibited by LaCl3. The results suggest that H2O2 may elevate cytoplasmic free Ca2+ concentrations in tobacco protoplasts, which mainly results from the entry of extracellular Ca2+, to regulate mitochondrial permeability transition. The signaling pathway of [Ca2+]i-mediated mitochondrial permeability transition was associated with H2O2-induced apoptosis in tobacco protoplasts.

  7. Lysosomal and mitochondrial permeabilization mediates zinc(II) cationic phthalocyanine phototoxicity.

    Science.gov (United States)

    Marino, Julieta; García Vior, María C; Furmento, Verónica A; Blank, Viviana C; Awruch, Josefina; Roguin, Leonor P

    2013-11-01

    In order to find a novel photosensitizer to be used in photodynamic therapy for cancer treatment, we have previously showed that the cationic zinc(II) phthalocyanine named Pc13, the sulfur-linked dye 2,9(10),16(17),23(24)-tetrakis[(2-trimethylammonium) ethylsulfanyl]phthalocyaninatozinc(II) tetraiodide, exerts a selective phototoxic effect on human nasopharynx KB carcinoma cells and induces an apoptotic response characterized by an increase in the activity of caspase-3. Since the activation of an apoptotic pathway by chemotherapeutic agents contributes to the elimination of malignant cells, in this study we investigated the molecular mechanisms underlying the antitumor action of Pc13. We found that after light exposure, Pc13 induced the production of reactive oxygen species (ROS), which are mediating the resultant cytotoxic action on KB cells. ROS led to an early permeabilization of lysosomal membranes as demonstrated by the reduction of lysosome fluorescence with acridine orange and the release of lysosomal proteases to cytosol. Treatment with antioxidants inhibited ROS generation, preserved the integrity of lysosomal membrane and increased cell proliferation in a concentration-dependent manner. Lysosome disruption was followed by mitochondrial depolarization, cytosolic release of cytochrome C and caspases activation. Although no change in the total amount of Bax was observed, the translocation of Bax from cytosol to mitochondria, the cleavage of the pro-apoptotic protein Bid, together with the decrease of the anti-apoptotic proteins Bcl-XL and Bcl-2 indicated the involvement of Bcl-2 family proteins in the induction of the mitochondrial pathway. It was also demonstrated that cathepsin D, but not caspase-8, contributed to Bid cleavage. In conclusion, Pc13-induced cell photodamage is triggered by ROS generation and activation of the mitochondrial apoptotic pathway through the release of lysosomal proteases. In addition, our results also indicated that Pc13 induced

  8. Quercetin protects against aluminium induced oxidative stress and promotes mitochondrial biogenesis via activation of the PGC-1α signaling pathway.

    Science.gov (United States)

    Sharma, Deep Raj; Sunkaria, Aditya; Wani, Willayat Yousuf; Sharma, Reeta Kumari; Verma, Deepika; Priyanka, Kumari; Bal, Amanjit; Gill, Kiran Dip

    2015-12-01

    The present investigation was carried out to elucidate a possible molecular mechanism related to the protective effect of quercetin administration against aluminium-induced oxidative stress on various mitochondrial respiratory complex subunits with special emphasis on the role of PGC-1α and its downstream targets, i.e. NRF-1, NRF-2 and Tfam in mitochondrial biogenesis. Aluminium lactate (10mg/kg b.wt./day) was administered intragastrically to rats, which were pre-treated with quercetin 6h before aluminium (10mg/kg b.wt./day, intragastrically) for 12 weeks. We found a decrease in ROS levels, mitochondrial DNA oxidation and citrate synthase activity in the hippocampus (HC) and corpus striatum (CS) regions of rat brain treated with quercetin. Besides this an increase in the mRNA levels of the mitochondrial encoded subunits - ND1, ND2, ND3, Cyt b, COX1, COX3 and ATPase6 along with increased expression of nuclear encoded subunits COX4, COX5A and COX5B of electron transport chain (ETC). In quercetin treated group an increase in the mitochondrial DNA copy number and mitochondrial content in both the regions of rat brain was observed. The PGC-1α was up regulated in quercetin treated rats along with NRF-1, NRF-2 and Tfam, which act downstream from PGC-1α. Electron microscopy results revealed a significant decrease in the mitochondrial cross-section area, mitochondrial perimeter length and increase in mitochondrial number in case of quercetin treated rats as compared to aluminium treated ones. Therefore it seems quercetin increases mitochondrial biogenesis and makes it an almost ideal flavanoid to control or limit the damage that has been associated with the defective mitochondrial function seen in many neurodegenerative diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. MAPK signaling pathways regulate mitochondrial-mediated apoptosis induced by isoorientin in human hepatoblastoma cancer cells.

    Science.gov (United States)

    Yuan, Li; Wang, Jing; Xiao, Haifang; Wu, Wanqiang; Wang, Yutang; Liu, Xuebo

    2013-03-01

    Isoorientin (ISO) (CAS RN: 4261-42-1) is a flavonoid compound that can be extracted from several plant species, such as Phyllostachys pubescens, Patrinia, and Drosophyllum lusitanicum. ISO is able to induce apoptosis through mitochondrial dysfunction and inhibition of PI3K/Akt signaling pathway in HepG2 cells, however, the effects of ISO on MAPK signaling pathways remain unknown. The present study investigated the effects of ISO on this pathway, and the roles of MAPK kinases on mitochondrial-mediated apoptosis in HepG2 cells. The results showed that ISO induced cell death in a dose- and time-dependent manner, and induction apoptosis is main cause for ISO-induced cytotoxicity in HepG2 cells. ISO significantly inhibited the levels of ERK1/2 kinase and increased the expression of JNK and p38 kinases. Furthermore, U0126 (an ERK1/2 inhibitor) significantly enhanced the ISO-induced the Bax/Bcl-2 ratio, the release of cytochrome c to the cytosol fraction, and the levels of cleaved caspase-3. While SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor) markedly prevented the expression of these proteins induced by ISO. Furthermore, the ROS inhibitor (NAC) notably promoted the inhibited effect of ISO on the ERK1/2 kinase. NAC also suppressed the p-JNK and p-p38, but failed to reverse the effects of ISO. These results demonstrated for the first time that ISO induces apoptosis in HepG2 cells through inactivating ERK1/2 kinase and activating JNK and p38 kinases, and ROS stimulated by ISO is able to activate the MAPK singaling pathway as the upstream signaling molecules. Initiating event of the mitochondrial-mediated apoptosis induced by ISO is MAPK signals.

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

    Science.gov (United States)

    Godzik, Katharina; Coleman, Michael P

    2015-04-01

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

  11. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis are mediated by reactive oxygen species in ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee [Radiation Biotechnology Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Young Sang [College of Natural Sciences, Chungnam National University, Daejeon (Korea, Republic of)

    2011-09-15

    Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging, and contributes to harmful effects in cultured cells and animal tissues. mtDNA biogenesis genes (NRF-1, TFAM) are essential for the maintenance of mtDNA, as well as the transcription and replication of mitochondrial genomes. Considering that oxidative stress is known to affect mitochondrial biogenesis, we hypothesized that ionizing radiation (IR)-induced reactive oxygen species (ROS) causes mtDNA deletion by modulating the mitochondrial biogenesis, thereby leading to cellular senescence. Therefore, we examined the effects of IR on ROS levels, cellular senescence, mitochondrial biogenesis, and mtDNA deletion in IMR-90 human lung fibroblast cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated at 4 or 8 Gy. Old cells at PD55, and H2O2-treated young cells at PD 39, were compared as a positive control. The IR increased the intracellular ROS level, senescence-associated {beta}-galactosidase (SA-{beta}-gal) activity, and mtDNA common deletion (4977 bp), and it decreased the mRNA expression of NRF-1 and TFAM in IMR-90 cells. Similar results were also observed in old cells (PD 55) and H{sub 2}O{sub 2}-treated young cells. To confirm that a increase in ROS level is essential for mtDNA deletion and changes of mitochondrial biogenesis in irradiated cells, the effects of N-acetylcysteine (NAC) were examined. In irradiated and H{sub 2}O{sub 2}-treated cells, 5 mM NAC significantly attenuated the increases of ROS, mtDNA deletion, and SA-{beta}-gal activity, and recovered from decreased expressions of NRF-1 and TFAM mRNA. These results suggest that ROS is a key cause of IR-induced mtDNA deletion, and the suppression of the mitochondrial biogenesis gene may mediate this process.

  12. A possible mechanism in DHEA-mediated protection against osteoarthritis.

    Science.gov (United States)

    Li, Wei-Jun; Tang, Lu-Ping; Xiong, Yan; Chen, Wei-Ping; Zhou, Xin-Die; Ding, Qian-Hai; Wu, Li-Dong

    2014-11-01

    Dehydroepiandrosterone (DHEA) and its ester form, DHEA-S, are the most abundant steroids in human plasma. Our previous studies showed that DHEA protects against osteoarthritis (OA). The aim of this paper was to explore the possible mechanisms that underlie DHEA-mediated protection against OA. We tested the expression of β-catenin, it was increased significantly in OA. Rabbit cartilage was treated with various concentrations of DHEA in both IL-1β-induced rabbit chondrocytes and in rabbit cartilage from the anterior cruciate ligament transaction-induced OA model. We found DHEA decreased the expression of β-catenin. Then we further activated Wnt/β-catenin signaling by β-catenin transfection and inactivated it by the inhibitor Dickkopf1 in chondrocytes to reveal its role in the pathogenesis of OA. It turns out the protective effect of DHEA was significantly decreased when Wnt/β-catenin signaling was activated, while inactivating Wnt/β-catenin signaling enhanced the effects of DHEA. Therefore, we hypothesize that DHEA probably exerted its chondroprotective effect by regulating Wnt/β-catenin signaling. Our findings demonstrate the critical role of Wnt/β-catenin signaling in DHEA-mediated protection against OA. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Ozone protects rat heart against ischemia-reperfusion injury: A role for oxidative preconditioning in attenuating mitochondrial injury.

    Science.gov (United States)

    Meng, Weixin; Xu, Ying; Li, Dandan; Zhu, Erjun; Deng, Li; Liu, Zonghong; Zhang, Guowei; Liu, Hongyu

    2017-04-01

    Ischemia-reperfusion injury (IRI) is a major cause of cardiac dysfunction during cardiovascular surgery, heart transplantation and cardiopulmonary bypass procedures. The purpose of the present study was to explore, firstly, whether ozone induces oxidative preconditioning by activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and, secondly, whether ozone oxidative preconditioning (OzoneOP) can protect the heart against IRI by attenuating mitochondrial damage. Rats were subjected to 30min of cardiac ischemia followed by 2h of reperfusion, with or without prior OzoneOP (100μg/kg/day) for 5 days. Antioxidant capacity, myocardial apoptosis and mitochondrial damage were evaluated and compared at the end of reperfusion. OzoneOP was found to increase antioxidant capacity and to protect the myocardium against IRI by attenuating mitochondrial damage and myocardial apoptosis. The study suggests a potential role for OzoneOP in protecting the heart against IRI during cardiovascular surgery, cardiopulmonary bypass procedures or transplantation.

  14. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection.

    Science.gov (United States)

    Sharkey, Liam K R; Edwards, Thomas A; O'Neill, Alex J

    2016-03-22

    Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to anin vitrotranslation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosomein vitro To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection.IMPORTANCEAntimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which includelsa(A),msr(A),optr(A), andvga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition. Copyright © 2016 Sharkey et al.

  15. Mitochondrial dysfunction in aging and longevity: a causal or protective role?

    Science.gov (United States)

    Pulliam, Daniel A; Bhattacharya, Arunabh; Van Remmen, Holly

    2013-10-20

    Among the most highly investigated theories of aging is the mitochondrial theory of aging. The basis of this theory includes a central role for altered or compromised mitochondrial function in the pathophysiologic declines associated with aging. In general, studies in various organisms, including nematodes, rodents, and humans, have largely upheld that aging is associated with mitochondrial dysfunction. However, results from a number of studies directly testing the mitochondrial theory of aging by modulating oxidant production or scavenging in vivo in rodents have generally been inconsistent with predictions of the theory. Interestingly, electron transport chain mutations or deletions in invertebrates and mice that causes mitochondrial dysfunction paradoxically leads to enhanced longevity, further challenging the mitochondrial theory of aging. How can mitochondrial dysfunction contribute to lifespan extension in the mitochondrial mutants, and what does it mean for the mitochondrial theory of aging? It will be important to determine the potential mechanisms that lead to enhanced longevity in the mammalian mitochondrial mutants.

  16. Sodium hydrosulfide attenuates hyperhomocysteinemia rat myocardial injury through cardiac mitochondrial protection.

    Science.gov (United States)

    Wang, Yuwen; Shi, Sa; Dong, Shiyun; Wu, Jichao; Song, Mowei; Zhong, Xin; Liu, Yanhong

    2015-01-01

    Hydrogen sulfide (H2S) plays an important role during rat myocardial injury. However, little is known about the role of H2S in hyperhomocysteinemia (HHcy)-induced cardiac dysfunction as well as the underlying mechanisms. In this study, we investigated whether sodium hydrosulfide (NaHS, a H2S donor) influences methionine-induced HHcy rat myocardial injury in intact rat hearts and primary neonatal rat cardiomyocytes. HHcy rats were induced by methionine (2.0 g/kg) and the daily administration of 80 μmol/L NaHS in the HHcy + NaHS treatment group. At the end of 4, 8, and 12 weeks, the ultrastructural alterations and functions of the hearts were observed using transmission electron microscopy and echocardiography system. The percentage of apoptotic cardiomyocytes, the mitochondrial membrane potential, and the production of reactive oxygen species (ROS) were measured. The expressions of cystathionine-γ-lyase (CSE), Bax and Bcl-2, caspase-3, phospho-endothelial nitric oxide synthase and the mitochondrial NOX4 and cytochrome c were analyzed by Western blotting. The results showed the cardiac dysfunction, the ultrastructural changes, and the apoptotic rate increase in the HHcy rat hearts. In the primary neonatal rat cardiomyocytes of HHcy group, ROS production was increased markedly, whereas the expression of CSE was decreased. However, treatment with NaHS significantly improved the HHcy rat hearts function, the ultrastructural changes, and decreased the levels of ROS in the primary neonatal rat cardiomyocytes administrated with HHcy group. Furthermore, NaHS down-regulated the expression of mitochondrial NOX4 and caspase-3 and Bax and inhibited the release of cytochrome c from mitochondria. In conclusion, H2S is involved in the attenuation of HHcy myocardial injury through the protection of cardiac mitochondria.

  17. A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling.

    Science.gov (United States)

    Patterson, Heide Christine; Gerbeth, Carolin; Thiru, Prathapan; Vögtle, Nora F; Knoll, Marko; Shahsafaei, Aliakbar; Samocha, Kaitlin E; Huang, Cher X; Harden, Mark Michael; Song, Rui; Chen, Cynthia; Kao, Jennifer; Shi, Jiahai; Salmon, Wendy; Shaul, Yoav D; Stokes, Matthew P; Silva, Jeffrey C; Bell, George W; MacArthur, Daniel G; Ruland, Jürgen; Meisinger, Chris; Lodish, Harvey F

    2015-10-20

    Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) govern cellular homeostasis by inducing signaling. H2O2 modulates the activity of phosphatases and many other signaling molecules through oxidation of critical cysteine residues, which led to the notion that initiation of ROS signaling is broad and nonspecific, and thus fundamentally distinct from other signaling pathways. Here, we report that H2O2 signaling bears hallmarks of a regular signal transduction cascade. It is controlled by hierarchical signaling events resulting in a focused response as the results place the mitochondrial respiratory chain upstream of tyrosine-protein kinase Lyn, Lyn upstream of tyrosine-protein kinase SYK (Syk), and Syk upstream of numerous targets involved in signaling, transcription, translation, metabolism, and cell cycle regulation. The active mediators of H2O2 signaling colocalize as H2O2 induces mitochondria-associated Lyn and Syk phosphorylation, and a pool of Lyn and Syk reside in the mitochondrial intermembrane space. Finally, the same intermediaries control the signaling response in tissues and species responsive to H2O2 as the respiratory chain, Lyn, and Syk were similarly required for H2O2 signaling in mouse B cells, fibroblasts, and chicken DT40 B cells. Consistent with a broad role, the Syk pathway is coexpressed across tissues, is of early metazoan origin, and displays evidence of evolutionary constraint in the human. These results suggest that H2O2 signaling is under control of a signal transduction pathway that links the respiratory chain to the mitochondrial intermembrane space-localized, ubiquitous, and ancient Syk pathway in hematopoietic and nonhematopoietic cells.

  18. ER-mediated stress induces mitochondrial-dependent caspases activation in NT2 neuron-like cells.

    Science.gov (United States)

    Arduino, Daniela M; Esteves, A Raquel; Domingues, A Filipa; Pereira, Claudia M F; Cardoso, Sandra M; Oliveira, Catarina R

    2009-11-30

    Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

  19. Mitochondrial superoxide mediates labile iron level: evidence from Mn-SOD-transgenic mice and heterozygous knockout mice and isolated rat liver mitochondria.

    Science.gov (United States)

    Ibrahim, Wissam H; Habib, Hosam M; Kamal, Hina; St Clair, Daret K; Chow, Ching K

    2013-12-01

    Superoxide is the main reactive oxygen species (ROS) generated by aerobic cells primarily in mitochondria. It is also capable of producing other ROS and reactive nitrogen species (RNS). Moreover, superoxide has the potential to release iron from its protein complexes. Unbound or loosely bound cellular iron, known as labile iron, can catalyze the formation of the highly reactive hydroxyl radical. ROS/RNS can cause mitochondrial dysfunction and damage. Manganese superoxide dismutase (Mn-SOD) is the chief ROS-scavenging enzyme and thereby the primary antioxidant involved in protecting mitochondria from oxidative damage. To investigate whether mitochondrial superoxide mediates labile iron in vivo, the levels of labile iron were determined in the tissues of mice overexpressing Mn-SOD and heterozygous Mn-SOD-knockout mice. Furthermore, the effect of increased mitochondrial superoxide generation on labile iron levels was determined in isolated rat liver mitochondria exposed to various electron transport inhibitors. The results clearly showed that increased expression of Mn-SOD significantly lowered the levels of labile iron in heart, liver, kidney, and skeletal muscle, whereas decreased expression of Mn-SOD significantly increased the levels of labile iron in the same organs. In addition, the data showed that peroxidative damage to membrane lipids closely correlated with the levels of labile iron in various tissues and that altering the status of Mn-SOD did not alter the status of other antioxidant systems. Results also showed that increased ROS production in isolated liver mitochondria significantly increased the levels of mitochondrial labile iron. These findings constitute the first evidence suggesting that mitochondrial superoxide is capable of releasing iron from its protein complexes in vivo and that it could also release iron from protein complexes contained within the organelle.

  20. The methyl donor S-adenosylmethionine prevents liver hypoxia and dysregulation of mitochondrial bioenergetic function in a rat model of alcohol-induced fatty liver disease

    Directory of Open Access Journals (Sweden)

    Adrienne L. King

    2016-10-01

    Conclusion: Collectively, these findings indicate that the hepato-protective effects of SAM against alcohol toxicity are mediated, in part, through a mitochondrial mechanism involving preservation of key mitochondrial bioenergetic parameters and the attenuation of hypoxic stress.

  1. SIRT1 facilitates hepatocellular carcinoma metastasis by promoting PGC-1α-mediated mitochondrial biogenesis.

    Science.gov (United States)

    Li, Yuming; Xu, Shangcheng; Li, Jing; Zheng, Lu; Feng, Min; Wang, Xiaoya; Han, Keqiang; Pi, Huifeng; Li, Min; Huang, Xiaobing; You, Nan; Tian, Yewang; Zuo, Guohua; Li, Hongyan; Zhao, Hongzhi; Deng, Ping; Yu, Zhengping; Zhou, Zhou; Liang, Ping

    2016-05-17

    SIRT1 is a multifaceted NAD+-dependent protein deacetylase known to act as a tumor promoter or suppressor in different cancers. Here, we describe a novel mechanism of SIRT1-induced hepatocellular carcinoma (HCC) metastasis. SIRT1 overexpression was frequently detected in human HCC specimens and was associated with microvascular invasion (P = 0.0039), advanced tumor node metastasis (TNM) stages (P = 0.0016), HCC recurrence (P = 0.021) and poor outcomes (P = 0.039). Lentivirus-mediated knockdown of SIRT1 in MHCC97H cells reduced invasion and metastasis in vitro and in vivo. SIRT1 depletion attenuated mitochondrial biogenesis and adenosine triphosphate (ATP) production but did not affect epithelial-mesenchymal transition. Elevated SIRT1 expression strongly correlated with the upregulation of PGC-1α in HCC specimens, and ectopic expression of SIRT1 increased PGC-1α levels. In cell assays and an orthotopic transplantation model, PGC-1α overexpression reversed the inhibitory effects of SIRT1 depletion on invasion and metastasis by enhancing mitochondrial biogenesis. These findings reveal the involvement of SIRT1 in HCC metastasis and provide a rationale for exploring therapeutic targets against the SIRT1/PGC-1α axis.

  2. SIRT1 facilitates hepatocellular carcinoma metastasis by promoting PGC-1α-mediated mitochondrial biogenesis

    Science.gov (United States)

    Li, Jing; Zheng, Lu; Feng, Min; Wang, Xiaoya; Han, Keqiang; Pi, Huifeng; Li, Min; Huang, Xiaobing; You, Nan; Tian, Yewang; Zuo, Guohua; Li, Hongyan; Zhao, Hongzhi; Deng, Ping; Yu, Zhengping; Zhou, Zhou; Liang, Ping

    2016-01-01

    SIRT1 is a multifaceted NAD+-dependent protein deacetylase known to act as a tumor promoter or suppressor in different cancers. Here, we describe a novel mechanism of SIRT1-induced hepatocellular carcinoma (HCC) metastasis. SIRT1 overexpression was frequently detected in human HCC specimens and was associated with microvascular invasion (P = 0.0039), advanced tumor node metastasis (TNM) stages (P = 0.0016), HCC recurrence (P = 0.021) and poor outcomes (P = 0.039). Lentivirus-mediated knockdown of SIRT1 in MHCC97H cells reduced invasion and metastasis in vitro and in vivo. SIRT1 depletion attenuated mitochondrial biogenesis and adenosine triphosphate (ATP) production but did not affect epithelial-mesenchymal transition. Elevated SIRT1 expression strongly correlated with the upregulation of PGC-1α in HCC specimens, and ectopic expression of SIRT1 increased PGC-1α levels. In cell assays and an orthotopic transplantation model, PGC-1α overexpression reversed the inhibitory effects of SIRT1 depletion on invasion and metastasis by enhancing mitochondrial biogenesis. These findings reveal the involvement of SIRT1 in HCC metastasis and provide a rationale for exploring therapeutic targets against the SIRT1/PGC-1α axis. PMID:27081083

  3. Spongionella Secondary Metabolites Protect Mitochondrial Function in Cortical Neurons against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Marta Leirós

    2014-01-01

    Full Text Available The marine habitat provides a large number of structurally-diverse bioactive compounds for drug development. Marine sponges have been studied over many years and are found to be a rich source of these bioactive chemicals. This study is focused on the evaluation of the activity of six diterpene derivatives isolated from Spongionella sp. on mitochondrial function using an oxidative in vitro stress model. The test compounds include the Gracilins (A, H, K, J and L and tetrahydroaplysulphurin-1. Compounds were co-incubated with hydrogen peroxide for 12 hours to determine their protective capacities and their effect on markers of apoptosis and Nrf2/ARE pathways was evaluated. Results conclude that Gracilins preserve neurons against oxidative damage, and that in particular, tetrahydroaplysulphurin-1 shows a complete neuroprotective activity. Oxidative stress is linked to mitochondrial dysfunction and consequently to neurodegenerative disorders like Parkinson and Alzheimer diseases, Friedreich ataxia or Amyotrophic lateral sclerosis. This neuroprotection against oxidation conditions suggest that these metabolites could be interesting lead candidates in drug development for neurodegenerative diseases.

  4. Mediator-assisted simultaneous probing of cytosolic and mitochondrial redox activity in living cells.

    Science.gov (United States)

    Heiskanen, Arto; Spégel, Christer; Kostesha, Natalie; Lindahl, Sofia; Ruzgas, Tautgirdas; Emnéus, Jenny

    2009-01-01

    This work describes an electron transfer mediator-assisted amperometric flow injection method for assessing redox enzyme activity in different subcellular compartments of the phosphoglucose isomerase deletion mutant strain of Saccharomyces cerevisiae, EBY44. The method is demonstrated using the ferricyanide-menadione double mediator system to study the effect of dicoumarol, an inhibitor of cytosolic and mitochondrial oxidoreductases and an uncoupler of the electron transport chain. Evaluation of the role of NAD(P)H-producing pathways in mediating biological effects is facilitated by introducing either fructose or glucose as the carbon source, yielding either NADH or NADPH through the glycolytic or pentose phosphate pathway, respectively. Respiratory noncompetent cells show greater inhibition of cytosolic menadione-reducing enzymes when NADH rather than NADPH is produced. Spectrophotometric in vitro assays show no difference between the cofactors. Respiratory competent cells show cytosolic inhibition only when NADPH is produced, whereas production of NADH reveals uncoupling at low dicoumarol concentrations and inhibition of complexes III and IV at higher concentrations. Spectrophotometric assays only indicate the presence of cytosolic inhibition regardless of the reduced cofactor used. This article shows the applicability of the amperometric method and emphasizes the significance of determining biological effects of chemicals in living cells.

  5. NOX2 amplifies acetaldehyde-mediated cardiomyocyte mitochondrial dysfunction in alcoholic cardiomyopathy

    Science.gov (United States)

    Brandt, Moritz; Garlapati, Venkata; Oelze, Matthias; Sotiriou, Efthymios; Knorr, Maike; Kröller-Schön, Swenja; Kossmann, Sabine; Schönfelder, Tanja; Morawietz, Henning; Schulz, Eberhard; Schultheiss, Heinz-Peter; Daiber, Andreas; Münzel, Thomas; Wenzel, Philip

    2016-01-01

    Alcoholic cardiomyopathy (ACM) resulting from excess alcohol consumption is an important cause of heart failure (HF). Although it is assumed that the cardiotoxicity of the ethanol (EtOH)-metabolite acetaldehyde (ACA) is central for its development and progression, the exact mechanisms remain obscure. Murine cardiomyocytes (CMs) exposed to ACA or EtOH showed increased superoxide (O2•−) levels and decreased mitochondrial polarization, both being normalized by NADPH oxidase (NOX) inhibition. C57BL/6 mice and mice deficient for the ACA-degrading enzyme mitochondrial aldehyde dehydrogenase (ALDH-2−/−) were fed a 2% EtOH diet for 5 weeks creating an ACA-overload. 2% EtOH-fed ALDH-2−/− mice exhibited a decreased cardiac function, increased heart-to-body and lung-to-body weight ratios, increased cardiac levels of the lipid peroxidation product malondialdehyde (MDA) as well as increased NOX activity and NOX2/glycoprotein 91phox (NOX2/gp91phox) subunit expression compared to 2% EtOH-fed C57BL/6 mice. Echocardiography revealed that ALDH-2−/−/gp91phox−/− mice were protected from ACA-overload-induced HF after 5 weeks of 2% EtOH-diet, demonstrating that NOX2-derived O2•− contributes to the development of ACM. Translated to human pathophysiology, we found increased gp91phox expression in endomyocardial biopsies of ACM patients. In conclusion, ACM is promoted by ACA-driven mitochondrial dysfunction and can be improved by ablation of NOX2/gp91phox. NOX2/gp91phox therefore might be a potential pharmacological target to treat ACM. PMID:27624556

  6. Ferricytochrome c protects mitochondrial cytochrome c oxidase against hydrogen peroxide-induced oxidative damage.

    Science.gov (United States)

    Sedlák, Erik; Fabian, Marian; Robinson, Neal C; Musatov, Andrej

    2010-11-30

    An excess of ferricytochrome c protects purified mitochondrial cytochrome c oxidase and bound cardiolipin from hydrogen peroxide-induced oxidative modification. All of the peroxide-induced changes within cytochrome c oxidase, such as oxidation of Trp(19,IV) and Trp(48,VIIc), partial dissociation of subunits VIa and VIIa, and generation of cardiolipin hydroperoxide, no longer take place in the presence of ferricytochrome c. Furthermore, ferricytochrome c suppresses the yield of H(2)O(2)-induced free radical detectable by electron paramagnetic resonance spectroscopy within cytochrome c oxidase. These protective effects are based on two mechanisms. The first involves the peroxidase/catalase-like activity of ferricytochrome c, which results in the decomposition of H(2)O(2), with the apparent bimolecular rate constant of 5.1±1.0M(-1)s(-1). Although this value is lower than the rate constant of a specialized peroxidase, the activity is sufficient to eliminate H(2)O(2)-induced damage to cytochrome c oxidase in the presence of an excess of ferricytochrome c. The second mechanism involves ferricytochrome c-induced quenching of free radicals generated within cytochrome c oxidase. These results suggest that ferricytochrome c may have an important role in protection of cytochrome c oxidase and consequently the mitochondrion against oxidative damage.

  7. Schisandrin B stereoisomers protect against hypoxia/reoxygenation-induced apoptosis and associated changes in the Ca(2+)-induced mitochondrial permeability transition and mitochondrial membrane potential in AML12 hepatocytes.

    Science.gov (United States)

    Chiu, Po Yee; Luk, Ka Fai; Leung, Hoi Yan; Ng, Ka Ming; Ko, Kam Ming

    2009-11-01

    The effects of the schisandrin B stereoisomers, (+/-)gamma-schisandrin [(+/-)gamma-Sch] and (-)schisandrin B [(-)Sch B], on hypoxia/reoxygenation-induced apoptosis were investigated in AML12 hepatocytes. Changes in cellular reduced glutathione (GSH) levels, Ca(2+)-induced mitochondrial permeability transitions (MPTs) and mitochondrial membrane potentials (Deltapsi(m) values) were also examined in (+/-)gamma-Sch- and (-)Sch B-treated cells, without or with hypoxia/reoxygenation challenge. The (+/-)gamma-Sch/(-)Sch B pretreatments (2.5-5.0 microm) protected against hypoxia/reoxygenation-induced apoptosis in AML12 cells in a concentration-dependent manner, with the (-)Sch B effect being more potent. Drug antiapoptotic effects were further evidenced by suppression of hypoxia/reoxygenation-induced mitochondrial cytochrome c release and subsequent cleavage of caspase 3 and poly-ADP-ribose polymerase by (-)Sch B pretreatment. Whereas hypoxia/reoxygenation challenge increased the extent of Ca(2+)-induced MPT pore opening, and Deltapsi(m), in AML12 hepatocytes, cytoprotection afforded by (+/-)gamma-Sch/(-)Sch B pretreatment against hypoxia/reoxygenation-induced apoptosis was associated with a decreased sensitivity to Ca(2+)-induced MPT and an increased Deltapsi(m) in both unchallenged and challenged cells, compared with the drug-free control. The results indicate that (+/-)gamma-Sch/(-)Sch B pretreatment protected against hypoxia/reoxygenation-induced apoptosis in AML12 hepatocytes and that the cytoprotection afforded by (+/-)gamma-Sch/(-)Sch B may at least in part be mediated by a decrease in sensitivity to Ca(2+)-induced MPT, which may in turn result from enhancement of cellular GSH levels by drug pretreatments.

  8. Adipose-specific deletion of TFAM increases mitochondrial oxidation and protects mice against obesity and insulin resistance

    DEFF Research Database (Denmark)

    Vernochet, Cecile; Mourier, Arnaud; Bezy, Olivier

    2012-01-01

    oxygen consumption and uncoupling. As a result, F-TFKO mice exhibit higher energy expenditure and are protected from age- and diet-induced obesity, insulin resistance, and hepatosteatosis, despite a greater food intake. Thus, TFAM deletion in the adipose tissue increases mitochondrial oxidation that has...

  9. Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-ß: A Protective Role of Melatonin

    Directory of Open Access Journals (Sweden)

    Sergio A. Rosales-Corral

    2012-01-01

    Full Text Available Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-ß (Aß generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranes in vivo, following intracerebral injection of fibrillar amyloid-ß (Aß. The purpose was to determine how Aß may be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aß in aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloid ß was injected, favoring an endogenous anti-inflammatory pathway.

  10. Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-β: A Protective Role of Melatonin

    Science.gov (United States)

    Rosales-Corral, Sergio A.; Lopez-Armas, Gabriela; Cruz-Ramos, Jose; Melnikov, Valery G.; Tan, Dun-Xian; Manchester, Lucien C.; Munoz, Ruben; Reiter, Russel J.

    2012-01-01

    Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-β (Aβ) generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranes in vivo, following intracerebral injection of fibrillar amyloid-β (Aβ). The purpose was to determine how Aβ may be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aβ in aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloid β was injected, favoring an endogenous anti-inflammatory pathway. PMID:22666620

  11. Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions

    Directory of Open Access Journals (Sweden)

    D.F. Meinerz

    2011-11-01

    Full Text Available We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS. The co-incubation with diphenyl diselenide (100 µM completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8% inhibition of the methylmercury effect. Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.

  12. Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions

    Directory of Open Access Journals (Sweden)

    D.F. Meinerz

    2011-11-01

    Full Text Available We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS. The co-incubation with diphenyl diselenide (100 µM completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8% inhibition of the methylmercury effect. Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.

  13. Reducing mitochondrial bound hexokinase II mediates transition from non-injurious into injurious ischemia/reperfusion of the intact heart

    NARCIS (Netherlands)

    R. Nederlof (Rianne); Gürel-Gurevin, E. (Ebru); O. Eerbeek (Otto); C. Xie (Chaoqin); Deijs, G.S.; Konkel, M. (Moritz); Hu, J. (Jun); N.C. Weber (Nina); C. Schumacher (Cees); A. Baartscheer (Antonius); E.G. Mik (Egbert); M.W. Hollmann (Markus); F.G. Akar (Fadi); C.J. Zuurbier (Coert J.)

    2016-01-01

    textabstractIschemia/reperfusion (I/R) of the heart becomes injurious when duration of the ischemic insult exceeds a certain threshold (approximately ≥20 min). Mitochondrial bound hexokinase II (mtHKII) protects against I/R injury, with the amount of mtHKII correlating with injury. Here, we examine

  14. Transcriptome-wide co-expression analysis identifies LRRC2 as a novel mediator of mitochondrial and cardiac function

    Science.gov (United States)

    Leleu, Marion; Rowe, Glenn C.; Palygin, Oleg; Bukowy, John D.; Kuo, Judy; Rech, Monika; Hermans-Beijnsberger, Steffie; Schaefer, Sebastian; Adami, Eleonora; Creemers, Esther E.; Heinig, Matthias; Schroen, Blanche; Arany, Zoltan; Petretto, Enrico; Geurts, Aron M.

    2017-01-01

    Mitochondrial dysfunction contributes to myriad monogenic and complex pathologies. To understand the underlying mechanisms, it is essential to define the full complement of proteins that modulate mitochondrial function. To identify such proteins, we performed a meta-analysis of publicly available gene expression data. Gene co-expression analysis of a large and heterogeneous compendium of microarray data nominated a sub-population of transcripts that whilst highly correlated with known mitochondrial protein-encoding transcripts (MPETs), are not themselves recognized as generating proteins either localized to the mitochondrion or pertinent to functions therein. To focus the analysis on a medically-important condition with a strong yet incompletely understood mitochondrial component, candidates were cross-referenced with an MPET-enriched module independently generated via genome-wide co-expression network analysis of a human heart failure gene expression dataset. The strongest uncharacterized candidate in the analysis was Leucine Rich Repeat Containing 2 (LRRC2). LRRC2 was found to be localized to the mitochondria in human cells and transcriptionally-regulated by the mitochondrial master regulator Pgc-1α. We report that Lrrc2 transcript abundance correlates with that of β-MHC, a canonical marker of cardiac hypertrophy in humans and experimentally demonstrated an elevation in Lrrc2 transcript in in vitro and in vivo rodent models of cardiac hypertrophy as well as in patients with dilated cardiomyopathy. RNAi-mediated Lrrc2 knockdown in a rat-derived cardiomyocyte cell line resulted in enhanced expression of canonical hypertrophic biomarkers as well as increased mitochondrial mass in the context of increased Pgc-1α expression. In conclusion, our meta-analysis represents a simple yet powerful springboard for the nomination of putative mitochondrially-pertinent proteins relevant to cardiac function and enabled the identification of LRRC2 as a novel mitochondrially

  15. Poly(C)-binding protein 1 (PCBP1) mediates housekeeping degradation of mitochondrial antiviral signaling (MAVS)

    Institute of Scientific and Technical Information of China (English)

    Xiang Zhou; Fuping You; Huihui Chen; Zhengfan Jiang

    2012-01-01

    Mitochondrial antiviral signaling (MAVS) is a key adaptor in cellular antiviral innate immunity.We previously identified poly(C)-binding protein 2 (PCBP2) as a feedback inhibitor of MAVS that facilitates its degradation after viral infection,but little is known about the regulatory potential of poly(C)-binding protein 1 (PCBP1),which highly resembles PCBP2.Here we report that PCBP1 mediates housekeeping degradation of MAVS using the same mechanism as PCBP2 employs.Overexpression of PCBP1 impairs MAVS-mediated antiviral responses,while knockdown of PCBP1 exerts the opposite effect.The suppression is due to PCBP1-induced MAVS degradation.We observe that PCBP1 and PCBP2 show synergy in MAVS inhibition,but their expression patterns are distinct:PCBP1 is stably and abundantly expressed,while PCBP2 shows low basal expression with rapid induction after infection.Individual knockdown and subcellular fractionation analyses reveal that unlike the postinfection inhibitor PCBP2,PCBP1 continuously eliminates cellular MAVS.Our findings unravel a critical role of PCBP1 in regulating MAVS for both finetuning the antivirai immunity and preventing inflammation.

  16. Cherry Valley ducks mitochondrial antiviral-signaling protein (MAVS mediated signaling pathway and antiviral activity research

    Directory of Open Access Journals (Sweden)

    Ning Li

    2016-09-01

    Full Text Available Mitochondrial antiviral-signaling protein (MAVS, an adaptor protein of retinoic acid-inducible gene I (RIG-I like receptors (RLRs-mediated signal pathway, is involved in innate immunity. In this study, Cherry Valley duck MAVS (duMAVS was cloned from the spleen and analyzed. duMAVS was determined to have a caspase activation and recruitment domain at N-terminal, followed by a proline rich domain and a transmembrane domain at C-terminal. Quantitative real time PCR indicated that duMAVS was expressed in all tissues tested across a broad expression spectrum. The expression of duMAVS was significantly up-regulated after infection with duck Tembusu virus. Overexpression of duMAVS could drive the activation of interferon-β, nuclear factor-κB, interferon regulatory factor 7, and many downstream factors (such as Mx, PKR, OAS, and IL-8 in duck embryo fibroblast cells. What’s more, RNA interference further confirmed that duMAVS was an important adaptor for IFN-β activation. The antiviral assay showed that duMAVS could suppress the various viral replications (duck Tembusu virus, novel reovirus, and duck plague virus at early stages of infection. Overall, these results showed that the main signal pathway mediated by duMAVS and it had a broad-spectrum antiviral ability. This research will be helpful to better understanding the innate immune system of ducks.

  17. Nelfinavir inhibits intra-mitochondrial calcium influx and protects brain against hypoxic-ischemic injury in neonatal mice.

    Directory of Open Access Journals (Sweden)

    Irina V Utkina-Sosunova

    Full Text Available Nelfinavir (NLF, an antiretroviral agent, preserves mitochondrial membranes integrity and protects mature brain against ischemic injury in rodents. Our study demonstrates that in neonatal mice NLF significantly limits mitochondrial calcium influx, the event associated with protection of the brain against hypoxic-ischemic insult (HI. Compared to the vehicle-treated mice, cerebral mitochondria from NLF-treated mice exhibited a significantly greater tolerance to the Ca(2+-induced membrane permeabilization, greater ADP-phosphorylating activity and reduced cytochrome C release during reperfusion. Pre-treatment with NLF or Ruthenium red (RuR significantly improved viability of murine hippocampal HT-22 cells, reduced Ca(2+ content and preserved membrane potential (Ψm in mitochondria following oxygen-glucose deprivation (OGD. Following histamine-stimulated Ca(2+ release from endoplasmic reticulum, in contrast to the vehicle-treated cells, the cells treated with NLF or RuR also demonstrated reduced Ca(2+ content in their mitochondria, the event associated with preserved Ψm. Because RuR inhibits mitochondrial Ca(2+ uniporter, we tested whether the NLF acts via the mechanism similar to the RuR. However, in contrast to the RuR, in the experiment with direct interaction of these agents with mitochondria isolated from naïve mice, the NLF did not alter mitochondrial Ca(2+ influx, and did not prevent Ca(2+ induced collapse of the Ψm. These data strongly argues against interaction of NLF and mitochondrial Ca(2+ uniporter. Although the exact mechanism remains unclear, our study is the first to show that NLF inhibits intramitochondrial Ca(2+ flux and protects developing brain against HI-reperfusion injury. This novel action of NLF has important clinical implication, because it targets a fundamental mechanism of post-ischemic cell death: intramitochondrial Ca(2+ overload → mitochondrial membrane permeabilization → secondary energy failure.

  18. Topiramate Protects Pericytes from Glucotoxicity: Role for Mitochondrial CA VA in Cerebromicrovascular Disease in Diabetes.

    Science.gov (United States)

    Patrick, Ping; Price, Tulin O; Diogo, Ana L; Sheibani, Nader; Banks, William A; Shah, Gul N

    Hyperglycemia in diabetes mellitus causes oxidative stress and pericyte depletion from the microvasculature of the brain thus leading to the Blood-Brain Barrier (BBB) disruption. The compromised BBB exposes the brain to circulating substances, resulting in neurotoxicity and neuronal cell death. The decline in pericyte numbers in diabetic mouse brain and pericyte apoptosis in high glucose cultures are caused by excess superoxide produced during enhanced respiration (mitochondrial oxidative metabolism of glucose). Superoxide is precursor to all Reactive Oxygen Species (ROS) which, in turn, cause oxidative stress. The rate of respiration and thus the ROS production is regulated by mitochondrial carbonic anhydrases (mCA) VA and VB, the two isoforms expressed in the mitochondria. Inhibition of both mCA: decreases the oxidative stress and restores the pericyte numbers in diabetic brain; and reduces high glucose-induced respiration, ROS, oxidative stress, and apoptosis in cultured brain pericytes. However, the individual role of the two isoforms has not been established. To investigate the contribution of mCA VA in ROS production and apoptosis, a mCA VA overexpressing brain pericyte cell line was engineered. These cells were exposed to high glucose and analyzed for the changes in ROS and apoptosis. Overexpression of mCA VA significantly increased pericyte ROS and apoptosis. Inhibition of mCA VA with topiramate prevented increases both in glucose-induced ROS and pericyte death. These results demonstrate, for the first time, that mCA VA regulates the rate of pericyte respiration. These findings identify mCA VA as a novel and specific therapeutic target to protect the cerebromicrovascular bed in diabetes.

  19. mtDNA T8993G mutation-induced F1F0-ATP synthase defect augments mitochondrial dysfunction associated with hypoxia/reoxygenation: the protective role of melatonin.

    Directory of Open Access Journals (Sweden)

    Wen-Yi Huang

    Full Text Available BACKGROUND: F1F0-ATP synthase (F1F0-ATPase plays important roles in regulating mitochondrial function during hypoxia, but the effect of F1F0-ATPase defect on hypoxia/reoxygenation (H/RO is unknown. The aim of this study was to investigate how mtDNA T8993G mutation (NARP-induced inhibition of F1F0-ATPase modulates the H/RO-induced mitochondrial dysfunction. In addition, the potential for melatonin, a potent antioxidant with multiple mitochondrial protective properties, to protect NARP cells exposed to H/RO was assessed. METHODS AND FINDINGS: NARP cybrids harboring 98% of mtDNA T8993G genes were established as an in vitro model for cells with F1F0-ATPase defect; their parental osteosarcoma 143B cells were studied for comparison. Treating the cells with H/RO using a hypoxic chamber resembles ischemia/reperfusion in vivo. NARP significantly enhanced apoptotic death upon H/RO detected by MTT assay and the trypan blue exclusion test of cell viability. Based on fluorescence probe-coupled laser scanning imaging microscopy, NARP significantly enhanced mitochondrial reactive oxygen species (mROS formation and mitochondrial Ca(2+ (mCa(2+ accumulation in response to H/RO, which augmented the depletion of cardiolipin, resulting in the retardation of mitochondrial movement. With stronger H/RO stress (either with longer reoxygenation duration, longer hypoxia duration, or administrating secondary oxidative stress following H/RO, NARP augmented H/RO-induced mROS formation to significantly depolarize mitochondrial membrane potential (ΔΨm, and enhance mCa(2+ accumulation and nitric oxide formation. Also, NARP augmented H/RO-induced mROS oxidized and depleted cardiolipin, thereby promoting permanent mitochondrial permeability transition, retarded mitochondrial movement, and enhanced apoptosis. Melatonin markedly reduced NARP-augmented H/RO-induced mROS formation and therefore significantly reduced mROS-mediated depolarization of ΔΨm and accumulation of mCa(2

  20. S-adenosyl-L-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brown, James Mike [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Kuhlman, Christopher [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Terneus, Marcus V. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Labenski, Matthew T. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Lamyaithong, Andre Benja; Ball, John G. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Lau, Serrine S. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Valentovic, Monica A., E-mail: Valentov@marshall.edu [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States)

    2014-12-01

    Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n = 5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S + A). APAP toxicity was confirmed by an increase (p < 0.05) in plasma ALT (U/l) and liver weight/10 g body weight relative to the Veh, SAMe and S + A groups 4 h following APAP treatment. SAMe administered 1 h post-APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S + A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S + A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1. - Highlights: • Acetaminophen (APAP) toxicity protected by S-adenosylmethionine (SAMe) • 4-Hydroxynonenal adducted to sarcosine dehydrogenase • 4-Hydroxynonenal adducted to carbamoyl phosphate synthetase-1 • SAMe reduced APAP mediated CPS-1 mitochondrial leakage.

  1. β-Sitosterol enhances cellular glutathione redox cycling by reactive oxygen species generated from mitochondrial respiration: protection against oxidant injury in H9c2 cells and rat hearts.

    Science.gov (United States)

    Wong, Hoi Shan; Chen, Na; Leong, Pou Kuan; Ko, Kam Ming

    2014-07-01

    Herba Cistanches (Cistanche deserticola Y. C. Ma) is a 'Yang-invigorating' tonic herb in Chinese medicine. Preliminary chemical analysis indicated that β-sitosterol (BS) is one of the chemical constituents in an active fraction of Herba Cistanches. To investigate whether BS is an active ingredient of Herba Cistanches, the effects of BS on H9c2 cells and rat hearts were examined. The results indicated that BS stimulated the mitochondrial ATP generation capacity in H9c2 cells, which was associated with the increased production of mitochondrial reactive oxygen species. BS also stimulated mitochondrial state 3 and state 4 respiration, with the resultant decrease in coupling efficiency. BS produced an up-regulation of cellular glutathione redox cycling and protected against hypoxia/reoxygenation-induced apoptosis in H9c2 cells. However, the protective effect of BS against myocardial ischemia/reperfusion injury was seen in female but not male rats ex vivo. The cardioprotection afforded by BS was likely mediated by an up-regulation of mitochondrial glutathione redox cycling in female rat hearts. In conclusion, the ensemble of results suggests that BS is an active ingredient of Herba Cistanches. The gender-dependent effect of BS on myocardial protection will further be investigated. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Metformin Protects Kidney Cells From Insulin-Mediated Genotoxicity In Vitro and in Male Zucker Diabetic Fatty Rats.

    Science.gov (United States)

    Othman, Eman Maher; Oli, R G; Arias-Loza, Paula-Anahi; Kreissl, Michael C; Stopper, Helga

    2016-02-01

    Hyperinsulinemia is thought to enhance cancer risk. A possible mechanism is induction of oxidative stress and DNA damage by insulin, Here, the effect of a combination of metformin with insulin was investigated in vitro and in vivo. The rationales for this were the reported antioxidative properties of metformin and the aim to gain further insights into the mechanisms responsible for protecting the genome from insulin-mediated oxidative stress and damage. The comet assay, a micronucleus frequency test, and a mammalian gene mutation assay were used to evaluate the DNA damage produced by insulin alone or in combination with metformin. For analysis of antioxidant activity, oxidative stress, and mitochondrial disturbances, the cell-free ferric reducing antioxidant power assay, the superoxide-sensitive dye dihydroethidium, and the mitochondrial membrane potential-sensitive dye 5,5',6,6'tetrachloro-1,1',3,3'-tetraethylbenzimidazol-carbocyanine iodide were applied. Accumulation of p53 and pAKT were analyzed. As an in vivo model, hyperinsulinemic Zucker diabetic fatty rats, additionally exposed to insulin during a hyperinsulinemic-euglycemic clamp, were treated with metformin. In the rat kidney samples, dihydroethidium staining, p53 and pAKT analysis, and quantification of the oxidized DNA base 8-oxo-7,8-dihydro-2'-deoxyguanosine were performed. Metformin did not show intrinsic antioxidant activity in the cell-free assay, but protected cultured cells from insulin-mediated oxidative stress, DNA damage, and mutation. Treatment of the rats with metformin protected their kidneys from oxidative stress and genomic damage induced by hyperinsulinemia. Metformin may protect patients from genomic damage induced by elevated insulin levels. This may support efforts to reduce the elevated cancer risk that is associated with hyperinsulinemia.

  3. CXCR5+ T helper cells mediate protective immunity against tuberculosis

    Science.gov (United States)

    Slight, Samantha R.; Rangel-Moreno, Javier; Gopal, Radha; Lin, Yinyao; Fallert Junecko, Beth A.; Mehra, Smriti; Selman, Moises; Becerril-Villanueva, Enrique; Baquera-Heredia, Javier; Pavon, Lenin; Kaushal, Deepak; Reinhart, Todd A.; Randall, Troy D.; Khader, Shabaana A.

    2013-01-01

    One third of the world’s population is infected with Mycobacterium tuberculosis (Mtb). Although most infected people remain asymptomatic, they have a 10% lifetime risk of developing active tuberculosis (TB). Thus, the current challenge is to identify immune parameters that distinguish individuals with latent TB from those with active TB. Using human and experimental models of Mtb infection, we demonstrated that organized ectopic lymphoid structures containing CXCR5+ T cells were present in Mtb-infected lungs. In addition, we found that in experimental Mtb infection models, the presence of CXCR5+ T cells within ectopic lymphoid structures was associated with immune control. Furthermore, in a mouse model of Mtb infection, we showed that activated CD4+CXCR5+ T cells accumulated in Mtb-infected lungs and produced proinflammatory cytokines. Mice deficient in Cxcr5 had increased susceptibility to TB due to defective T cell localization within the lung parenchyma. We demonstrated that CXCR5 expression in T cells mediated correct T cell localization within TB granulomas, promoted efficient macrophage activation, protected against Mtb infection, and facilitated lymphoid follicle formation. These data demonstrate that CD4+CXCR5+ T cells play a protective role in the immune response against TB and highlight their potential use for future TB vaccine design and therapy. PMID:23281399

  4. TGF-β1-mediated differentiation of fibroblasts is associated with increased mitochondrial content and cellular respiration.

    Science.gov (United States)

    Negmadjanov, Ulugbek; Godic, Zarko; Rizvi, Farhan; Emelyanova, Larisa; Ross, Gracious; Richards, John; Holmuhamedov, Ekhson L; Jahangir, Arshad

    2015-01-01

    Cytokine-dependent activation of fibroblasts to myofibroblasts, a key event in fibrosis, is accompanied by phenotypic changes with increased secretory and contractile properties dependent on increased energy utilization, yet changes in the energetic profile of these cells are not fully described. We hypothesize that the TGF-β1-mediated transformation of myofibroblasts is associated with an increase in mitochondrial content and function when compared to naive fibroblasts. Cultured NIH/3T3 mouse fibroblasts treated with TGF-β1, a profibrotic cytokine, or vehicle were assessed for transformation to myofibroblasts (appearance of α-smooth muscle actin [α-SMA] stress fibers) and associated changes in mitochondrial content and functions using laser confocal microscopy, Seahorse respirometry, multi-well plate reader and biochemical protocols. Expression of mitochondrial-specific proteins was determined using western blotting, and the mitochondrial DNA quantified using Mitochondrial DNA isolation kit. Treatment with TGF-β1 (5 ng/mL) induced transformation of naive fibroblasts into myofibroblasts with a threefold increase in the expression of α-SMA (6.85 ± 0.27 RU) compared to cells not treated with TGF-β1 (2.52 ± 0.11 RU). TGF-β1 exposure increased the number of mitochondria in the cells, as monitored by membrane potential sensitive dye tetramethylrhodamine, and expression of mitochondria-specific proteins; voltage-dependent anion channels (0.54 ± 0.05 vs. 0.23 ± 0.05 RU) and adenine nucleotide transporter (0.61 ± 0.11 vs. 0.22 ± 0.05 RU), as well as mitochondrial DNA content (530 ± 12 μg DNA/106 cells vs. 307 ± 9 μg DNA/106 cells in control). TGF-β1 treatment was associated with an increase in mitochondrial function with a twofold increase in baseline oxygen consumption rate (2.25 ± 0.03 vs. 1.13 ± 0.1 nmol O2/min/106 cells) and FCCP-induced mitochondrial respiration (2.87 ± 0.03 vs. 1.46 ± 0.15 nmol O2/min/106 cells). TGF-β1 induced differentiation

  5. TGF-β1-mediated differentiation of fibroblasts is associated with increased mitochondrial content and cellular respiration.

    Directory of Open Access Journals (Sweden)

    Ulugbek Negmadjanov

    Full Text Available Cytokine-dependent activation of fibroblasts to myofibroblasts, a key event in fibrosis, is accompanied by phenotypic changes with increased secretory and contractile properties dependent on increased energy utilization, yet changes in the energetic profile of these cells are not fully described. We hypothesize that the TGF-β1-mediated transformation of myofibroblasts is associated with an increase in mitochondrial content and function when compared to naive fibroblasts.Cultured NIH/3T3 mouse fibroblasts treated with TGF-β1, a profibrotic cytokine, or vehicle were assessed for transformation to myofibroblasts (appearance of α-smooth muscle actin [α-SMA] stress fibers and associated changes in mitochondrial content and functions using laser confocal microscopy, Seahorse respirometry, multi-well plate reader and biochemical protocols. Expression of mitochondrial-specific proteins was determined using western blotting, and the mitochondrial DNA quantified using Mitochondrial DNA isolation kit.Treatment with TGF-β1 (5 ng/mL induced transformation of naive fibroblasts into myofibroblasts with a threefold increase in the expression of α-SMA (6.85 ± 0.27 RU compared to cells not treated with TGF-β1 (2.52 ± 0.11 RU. TGF-β1 exposure increased the number of mitochondria in the cells, as monitored by membrane potential sensitive dye tetramethylrhodamine, and expression of mitochondria-specific proteins; voltage-dependent anion channels (0.54 ± 0.05 vs. 0.23 ± 0.05 RU and adenine nucleotide transporter (0.61 ± 0.11 vs. 0.22 ± 0.05 RU, as well as mitochondrial DNA content (530 ± 12 μg DNA/106 cells vs. 307 ± 9 μg DNA/106 cells in control. TGF-β1 treatment was associated with an increase in mitochondrial function with a twofold increase in baseline oxygen consumption rate (2.25 ± 0.03 vs. 1.13 ± 0.1 nmol O2/min/106 cells and FCCP-induced mitochondrial respiration (2.87 ± 0.03 vs. 1.46 ± 0.15 nmol O2/min/106 cells.TGF-β1 induced

  6. Mechanism of Mitochondrial Connexin43′s Protection of the Neurovascular Unit under Acute Cerebral Ischemia-Reperfusion Injury

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    Shuai Hou

    2016-05-01

    Full Text Available We observed mitochondrial connexin43 (mtCx43 expression under cerebral ischemia-reperfusion (I/R injury, analyzed its regulation, and explored its protective mechanisms. Wistar rats were divided into groups based on injections received before middle cerebral artery occlusion (MCAO. Cerebral infarction volume was detected by 2,3,5-triphenyltetrazolim chloride staining, and cell apoptosis was observed by transferase dUTP nick end labeling. We used transmission electron microscopy to observe mitochondrial morphology and determined superoxide dismutase (SOD activity and malondialdehyde (MDA content. MtCx43, p-mtCx43, protein kinase C (PKC, and p-PKC expression were detected by Western blot. Compared with those in the IR group, cerebral infarction volumes in the carbenoxolone (CBX and diazoxide (DZX groups were obviously smaller, and the apoptosis indices were down-regulated. Mitochondrial morphology was damaged after I/R, especially in the IR and 5-hydroxydecanoic acid (5-HD groups. Similarly, decreased SOD activity and increased MDA were observed after MCAO; CBX, DZX, and phorbol-12-myristate-13-acetate (PMA reduced mitochondrial functional injury. Expression of mtCx43 and p-mtCx43 and the p-Cx43/Cx43 ratio were significantly lower in the IR group than in the sham group. These abnormalities were ameliorated by CBX, DZX, and PMA. MtCx43 may protect the neurovascular unit from acute cerebral IR injury via PKC activation induced by mitoKATP channel agonists.

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

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    Wei Zhang

    2015-01-01

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

  8. Protocatechuic acid protects brain mitochondrial function in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Semaming, Yoswaris; Sripetchwandee, Jirapas; Sa-Nguanmoo, Piangkwan; Pintana, Hiranya; Pannangpetch, Patchareewan; Chattipakorn, Nipon; Chattipakorn, Siriporn C

    2015-10-01

    Brain mitochondrial dysfunction has been demonstrated in diabetic animals with neurodegeneration. Protocatechuic acid (PCA), a major metabolite of anthocyanin, has been shown to exert glycemic control and oxidative stress reduction in the heart. However, its effects on oxidative stress and mitochondrial function in the brain under diabetic condition have never been investigated. We found that PCA exerted glycemic control, attenuates brain mitochondrial dysfunction, and contributes to the prevention of brain oxidative stress in diabetic rats.

  9. The Protective Effect of Icariin on Mitochondrial Transport and Distribution in Primary Hippocampal Neurons from 3× Tg-AD Mice.

    Science.gov (United States)

    Chen, Yijing; Han, Shuangxue; Huang, Xiuxian; Ni, Jiazuan; He, Xiaoyang

    2016-01-27

    Icariin, a pharmacologically active component isolated from the Chinese herb Epimedium, has been shown to improve spatial learning and memory abilities in Alzheimer's disease (AD) rats through inhibition of Aβ production and tau protein hyperphosphorylation. However, the potential mechanism of icariin-induced protective effects against mitochondrial dysfunctions in AD still remains unclear. In the present study, we investigated the effect of icariin on the modulation of mitochondrial transport and distribution in primary hippocampal cultures from triple-transgenic (3× Tg) AD mice. The results showed that icariin enhanced mitochondrial motility and increased mitochondrial index and mitochondrial length and size in the diseased neurons. Additionally, the expression of the key mitochondrial enzyme, pyruvate dehydrogenase-E1α (PDHE1α), and the post synaptic density protein 95 (PSD95), was preserved in AD neurons after icariin treatment, accompanied by a downregulation of Aβ and phosphorylated tau expression in the corresponding areas. Further study showed that icariin treatment resulted in a decrease in mitochondrial fission protein dynamin-related protein 1 (Drp1) and an increase in fusion protein Mitofusin 2 (Mfn2). These data indicate that icariin can promote mitochondrial transport, protect mitochondria against fragmentation and preserve the expression of mitochondrial and synaptic functional proteins in AD neurons. Thus, icariin may be a potential therapeutic complement for AD and other mitochondrial malfunction-related neuronal degenerative diseases.

  10. The Protective Effect of Icariin on Mitochondrial Transport and Distribution in Primary Hippocampal Neurons from 3× Tg-AD Mice

    Directory of Open Access Journals (Sweden)

    Yijing Chen

    2016-01-01

    Full Text Available Icariin, a pharmacologically active component isolated from the Chinese herb Epimedium, has been shown to improve spatial learning and memory abilities in Alzheimer’s disease (AD rats through inhibition of Aβ production and tau protein hyperphosphorylation. However, the potential mechanism of icariin-induced protective effects against mitochondrial dysfunctions in AD still remains unclear. In the present study, we investigated the effect of icariin on the modulation of mitochondrial transport and distribution in primary hippocampal cultures from triple-transgenic (3× Tg AD mice. The results showed that icariin enhanced mitochondrial motility and increased mitochondrial index and mitochondrial length and size in the diseased neurons. Additionally, the expression of the key mitochondrial enzyme, pyruvate dehydrogenase-E1α (PDHE1α, and the post synaptic density protein 95 (PSD95, was preserved in AD neurons after icariin treatment, accompanied by a downregulation of Aβ and phosphorylated tau expression in the corresponding areas. Further study showed that icariin treatment resulted in a decrease in mitochondrial fission protein dynamin-related protein 1 (Drp1 and an increase in fusion protein Mitofusin 2 (Mfn2. These data indicate that icariin can promote mitochondrial transport, protect mitochondria against fragmentation and preserve the expression of mitochondrial and synaptic functional proteins in AD neurons. Thus, icariin may be a potential therapeutic complement for AD and other mitochondrial malfunction-related neuronal degenerative diseases.

  11. Induction of mitochondrial-mediated apoptosis by Morinda citrifolia (Noni) in human cervical cancer cells.

    Science.gov (United States)

    Gupta, Rakesh Kumar; Banerjee, Ayan; Pathak, Suajta; Sharma, Chandresh; Singh, Neeta

    2013-01-01

    Cervical cancer is the second most common cause of cancer in women and has a high mortality rate. Cisplatin, an antitumor agent, is generally used for its treatment. However, the administration of cisplatin is associated with side effects and intrinsic resistance. Morinda citrifolia (Noni), a natural plant product, has been shown to have anti-cancer properties. In this study, we used Noni, cisplatin, and the two in combination to study their cytotoxic and apoptosis-inducing effects in cervical cancer HeLa and SiHa cell lines. We demonstrate here, that Noni/Cisplatin by themselves and their combination were able to induce apoptosis in both these cell lines. Cisplatin showed slightly higher cell killing as compared to Noni and their combination showed additive effects. The observed apoptosis appeared to be mediated particularly through the up-regulation of p53 and pro-apoptotic Bax proteins, as well as down- regulation of the anti-apoptotic Bcl-2, Bcl-XL proteins and survivin. Augmentation in the activity of caspase-9 and -3 was also observed, suggesting the involvement of the intrinsic mitochondrial pathway of apoptosis for both Noni and Cisplatin in HeLa and SiHa cell lines.

  12. ADA1 and NET1 Genes of Yeast Mediate Both Chromosome Maintenance and Mitochondrial $\\rho^{-}$ Mutagenesis

    CERN Document Server

    Koltovaya, N A; Tchekhouta, I A; Devin, A B

    2002-01-01

    An increase in the mitochondrial (mt) rho^- mutagenesis is a well-known respose of yeast cells to mutations in the numerous nuclear genes as well as to various kinds of stress. Notwithstanding the extensive studies during several decades the biological significance of this response is not yet fully understood. The genetic approach to solution of this subject includes the study of genes that are required for the high incidence of spontaneous rho^- mutants. Previously we found that mutations in certain nuclear genes including CDC28, the central cell-cycle regulation gene, may decrease the spontaneous rho^- mutability and simultaneously affect maintenance of the yeast chromosomes and plasmids. The present work provides data on identification of two more genes, resembling CDC28 in this respect. These genes NET1 and ADA1 mediate important regulatory protein-protein interactions in the yeast cell. The effects of net1 and ada1 mutations on the maintenance of yeast mt genome, chromosomes and plasmids as well as on ce...

  13. Measurement of mitochondrial Ca2+ transport mediated by three transport proteins: VDAC1, the Na+/Ca2+ exchanger, and the Ca2+ uniporter.

    Science.gov (United States)

    Ben-Hail, Danya; Palty, Raz; Shoshan-Barmatz, Varda

    2014-02-01

    Ca(2+) is a ubiquitous cellular signal, with changes in intracellular Ca(2+) concentration not only stimulating a number of intercellular events but also triggering cell death pathways, including apoptosis. Mitochondrial Ca(2+) uptake and release play pivotal roles in cellular physiology by regulating intracellular Ca(2+) signaling, energy metabolism and cell death. Ca(2+) transport across the inner and outer mitochondrial membranes is mediated by several proteins, including channels, antiporters, and a uniporter. In this article, we present the background to several methods now established for assaying mitochondrial Ca(2+) transport activity across both mitochondrial membranes. The first of these is Ca(2+) transport mediated by the outer mitochondrial protein, the voltage-dependent anion-selective channel protein 1 (VDAC1, also known as porin 1), both as a purified protein reconstituted into a planar lipid bilayer (PLB) or into liposomes and as a mitochondrial membrane-embedded protein. The second method involves isolated mitochondria for assaying the activity of an inner mitochondrial membrane transport protein, the mitochondrial Ca(2+) uniporter (MCU) that transports Ca(2+) and is powered by the steep mitochondrial membrane potential. In the event of Ca(2+) overload, this leads to opening of the mitochondrial permeability transition pore (MPTP) and cell death. The third method describes how Na(+)-dependent mitochondrial Ca(2+) efflux mediated by mitochondrial NCLX, a member of the Na(+)/Ca(2+) exchanger superfamily, can be assayed in digitonin-permeabilized HEK-293 cells. The Ca(2+)-transport assays can be performed under various conditions and in combination with inhibitors, allowing detailed characterization of the transport activity of interest.

  14. MICU1 is an essential gatekeeper for MCU-mediated mitochondrial Ca(2+) uptake that regulates cell survival.

    Science.gov (United States)

    Mallilankaraman, Karthik; Doonan, Patrick; Cárdenas, César; Chandramoorthy, Harish C; Müller, Marioly; Miller, Russell; Hoffman, Nicholas E; Gandhirajan, Rajesh Kumar; Molgó, Jordi; Birnbaum, Morris J; Rothberg, Brad S; Mak, Don-On Daniel; Foskett, J Kevin; Madesh, Muniswamy

    2012-10-26

    Mitochondrial Ca(2+) (Ca(2+)(m)) uptake is mediated by an inner membrane Ca(2+) channel called the uniporter. Ca(2+) uptake is driven by the considerable voltage present across the inner membrane (ΔΨ(m)) generated by proton pumping by the respiratory chain. Mitochondrial matrix Ca(2+) concentration is maintained five to six orders of magnitude lower than its equilibrium level, but the molecular mechanisms for how this is achieved are not clear. Here, we demonstrate that the mitochondrial protein MICU1 is required to preserve normal [Ca(2+)](m) under basal conditions. In its absence, mitochondria become constitutively loaded with Ca(2+), triggering excessive reactive oxygen species generation and sensitivity to apoptotic stress. MICU1 interacts with the uniporter pore-forming subunit MCU and sets a Ca(2+) threshold for Ca(2+)(m) uptake without affecting the kinetic properties of MCU-mediated Ca(2+) uptake. Thus, MICU1 is a gatekeeper of MCU-mediated Ca(2+)(m) uptake that is essential to prevent [Ca(2+)](m) overload and associated stress.

  15. Human Chorionic Gonadotropin Protects Vascular Endothelial Cells from Oxidative Stress by Apoptosis Inhibition, Cell Survival Signalling Activation and Mitochondrial Function Protection

    Directory of Open Access Journals (Sweden)

    Daniela Surico

    2015-07-01

    Full Text Available Background/Aim: Previous reports have made it hypothetically possible that human chorionic gonadotropin (hCG could protect against the onset of pregnancy-related pathological conditions by acting as an antioxidant. In the present study we planned to examine the effects of hCG against oxidative stress in human umbilical vein endothelial cells (HUVEC. Methods: HUVEC were subjected to peroxidation by hydrogen peroxide. The modulation of nitric oxide (NO release by hCG and its effects on cell viability, glutathione (GSH levels, mitochondrial membrane potential and mitochondrial transition pore opening (MPTP were examined by specific dyes. Endothelial and inducible NO synthase (eNOS and iNOS, Akt and extracellular -signal-regulated kinases 1/2 (ERK1/2 activation and markers of apoptosis were analyzed by Western Blot. Results: In HUVEC, hCG reduced NO release by modulating eNOS and iNOS. Moreover, hCG protected HUVEC against oxidative stress by preventing GSH reduction and apoptosis, by maintaining Akt and ERK1/2 activation and by keeping mitochondrial function. Conclusion: The present results have for the first time shown protective effects exerted by hCG on vascular endothelial function, which would be achieved by modulation of NO release, antioxidant and antiapoptotic actions and activation of cell survival signalling. These findings could have clinical implications in the management of pregnancy-related disorders.

  16. Diabetic Inhibition of Preconditioning- and Postconditioning-Mediated Myocardial Protection against Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Xia Yin

    2012-01-01

    Full Text Available Ischemic preconditioning (IPC or postconditioning (Ipost is proved to efficiently prevent ischemia/reperfusion injuries. Mortality of diabetic patients with acute myocardial infarction was found to be 2–6 folds higher than that of non-diabetic patients with same myocardial infarction, which may be in part due to diabetic inhibition of IPC- and Ipost-mediated protective mechanisms. Both IPC- and Ipost-mediated myocardial protection is predominantly mediated by stimulating PI3K/Akt and associated GSK-3β pathway while diabetes-mediated pathogenic effects are found to be mediated by inhibiting PI3K/Akt and associated GSK-3β pathway. Therefore, this review briefly introduced the general features of IPC- and Ipost-mediated myocardial protection and the general pathogenic effects of diabetes on the myocardium. We have collected experimental evidence that indicates the diabetic inhibition of IPC- and Ipost-mediated myocardial protection. Increasing evidence implies that diabetic inhibition of IPC- and Ipost-mediated myocardial protection may be mediated by inhibiting PI3K/Akt and associated GSK-3β pathway. Therefore any strategy to activate PI3K/Akt and associated GSK-3β pathway to release the diabetic inhibition of both IPC and Ipost-mediated myocardial protection may provide the protective effect against ischemia/reperfusion injuries.

  17. Chronic Arsenic Exposure-Induced Oxidative Stress is Mediated by Decreased Mitochondrial Biogenesis in Rat Liver.

    Science.gov (United States)

    Prakash, Chandra; Kumar, Vijay

    2016-09-01

    The present study was executed to study the effect of chronic arsenic exposure on generation of mitochondrial oxidative stress and biogenesis in rat liver. Chronic sodium arsenite treatment (25 ppm for 12 weeks) decreased mitochondrial complexes activity in rat liver. There was a decrease in mitochondrial superoxide dismutase (MnSOD) activity in arsenic-treated rats that might be responsible for increased protein and lipid oxidation as observed in our study. The messenger RNA (mRNA) expression of mitochondrial and nuclear-encoded subunits of complexes I (ND1 and ND2) and IV (COX I and COX IV) was downregulated in arsenic-treated rats only. The protein and mRNA expression of MnSOD was reduced suggesting increased mitochondrial oxidative damage after arsenic treatment. There was activation of Bax and caspase-3 followed by release of cytochrome c from mitochondria suggesting induction of apoptotic pathway under oxidative stress. The entire phenomenon was associated with decrease in mitochondrial biogenesis as evident by decreased protein and mRNA expression of nuclear respiratory factor 1 (NRF-1), nuclear respiratory factor 2 (NRF-2), peroxisome proliferator activator receptor gamma-coactivator 1α (PGC-1α), and mitochondrial transcription factor A (Tfam) in arsenic-treated rat liver. The results of the present study indicate that arsenic-induced mitochondrial oxidative stress is associated with decreased mitochondrial biogenesis in rat liver that may present one of the mechanisms for arsenic-induced hepatotoxicity.

  18. CCAAT/enhancer binding protein {beta} deletion increases mitochondrial function and protects mice from LXR-induced hepatic steatosis

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shaikh M., E-mail: rmizanoor@hotmail.com [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Choudhury, Mahua; Janssen, Rachel C.; Baquero, Karalee C. [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Miyazaki, Makoto [Division of Renal Diseases and Hypertension, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Friedman, Jacob E. [Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States); Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, Aurora, CO 80045 (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer LXR agonist activation increases liver TG accumulation by increasing lipogenesis. Black-Right-Pointing-Pointer C/EBP{beta}{sup -/-} mouse prevents LXR activation-mediated induction of hepatic lipogenesis. Black-Right-Pointing-Pointer C/EBP{beta} deletion increases mitochondrial transport chain function. Black-Right-Pointing-Pointer Beneficial effects of LXR activation on liver cholesterol metabolism did not change. Black-Right-Pointing-Pointer C/EBP{beta} inhibition might have important therapeutic potential. -- Abstract: Drugs designed specifically to activate liver X receptors (LXRs) have beneficial effects on lowering cholesterol metabolism and inflammation but unfortunately lead to severe hepatic steatosis. The transcription factor CCAAT/enhancer binding protein beta (C/EBP{beta}) is an important regulator of liver gene expression but little is known about its involvement in LXR-based steatosis and cholesterol metabolism. The present study investigated the role of C/EBP{beta} expression in LXR agonist (T0901317)-mediated alteration of hepatic triglyceride (TG) and lipogenesis in mice. C/EBP{beta} deletion in mice prevented LXR agonist-mediated induction of lipogenic gene expression in liver in conjunction with significant reduction of liver TG accumulation. Surprisingly, C/EBP{beta}{sup -/-} mice showed a major increase in liver mitochondrial electron chain function compared to WT mice. Furthermore, LXR activation in C/EBP{beta}{sup -/-} mice increased the expression of liver ATP-binding cassette transporter ABCG1, a gene implicated in cholesterol efflux and reducing blood levels of total and LDL-cholesterol. Together, these findings establish a central role for C/EBP{beta} in the LXR-mediated steatosis and mitochondrial function, without impairing the influence of LXR activation on lowering LDL and increasing HDL-cholesterol. Inactivation of C/EBP{beta} might therefore be an important therapeutic strategy to prevent LXR

  19. Bcl-2 protects against FCCP-induced apoptosis and mitochondrial membrane potential depolarization in PC12 cells.

    Science.gov (United States)

    Dispersyn, G; Nuydens, R; Connors, R; Borgers, M; Geerts, H

    1999-08-05

    This report addresses the relation between Bcl-2 and mitochondrial membrane potential (DeltaPsi(m)) in apoptotic cell death. Rat pheochromocytoma (PC12) cells are differentiated into neuron-like cells with nerve growth factor (NGF). It is known that Bcl-2 can attenuate apoptosis induced by deprivation of neurotrophic factor. The protective effect of Bcl-2 has been correlated with preservation of DeltaPsi(m). Protonophores, such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), collapse the proton gradient across the mitochondrial inner membrane, resulting in a complete abolition of the mitochondrial membrane potential. Based on the analysis of morphology, of phosphatidylserine exposure and of nuclear fragmentation we conclude that FCCP induces apoptosis in PC12 cells, which can be prevented by overexpression of Bcl-2. To determine whether the cytoprotective effect of Bcl-2 is due to stabilization of DeltaPsi(m), we investigated the effect of Bcl-2 on changes in DeltaPsi(m), induced by FCCP in PC12 cells. We showed that treatment with FCCP induced a reduction in DeltaPsi(m), as assessed with the lipophilic cationic membrane potential-sensitive dye JC-1, and that Bcl-2 protects against FCCP-induced changes in NGF differentiated PC12 cells. Our data indicate that Bcl-2 protects against FCCP-induced cell death by stabilizing DeltaPsi(m).

  20. Silica nanoparticles mediated neuronal cell death in corpus striatum of rat brain: implication of mitochondrial, endoplasmic reticulum and oxidative stress

    Science.gov (United States)

    Parveen, Arshiya; Rizvi, Syed Husain Mustafa; Mahdi, Farzana; Tripathi, Sandeep; Ahmad, Iqbal; Shukla, Rajendra K.; Khanna, Vinay K.; Singh, Ranjana; Patel, Devendra K.; Mahdi, Abbas Ali

    2014-11-01

    Extensive uses of silica nanoparticles (SiNPs) in biomedical and industrial fields have increased the risk of exposure, resulting concerns about their safety. We focussed on some of the safety aspects by studying neurobehavioural impairment, oxidative stress (OS), neurochemical and ultrastructural changes in corpus striatum (CS) of male Wistar rats exposed to 80-nm SiNPs. Moreover, its role in inducing mitochondrial and endoplasmic reticulum (ER) stress-mediated neuronal apoptosis was also investigated. The results demonstrated impairment in neurobehavioural indices, and a significant increase in lipid peroxide levels (LPO), hydrogen peroxide (H2O2), superoxide (O2 -) and protein carbonyl content, whereas there was a significant decrease in the activities of the enzymes, manganese superoxide dismutase (Mn SOD), glutathione peroxidase (GPx), catalase (CAT) and reduced glutathione (GSH) content, suggesting impaired antioxidant defence system. Protein (cytochrome c, Bcl-2, Bax, p53, caspase-3, caspase 12 and CHOP/Gadd153) and mRNA (Bcl-2, Bax, p53 and CHOP/Gadd153, cytochrome c) expression studies of mitochondrial and ER stress-related apoptotic factors suggested that both the cell organelles were involved in OS-mediated apoptosis in treated rat brain CS. Moreover, electron microscopic studies clearly showed mitochondrial and ER dysfunction. In conclusion, the result of the study suggested that subchronic SiNPs' exposure has the potential to alter the behavioural activity and also to bring about changes in biochemical, neurochemical and ultrastructural profiles in CS region of rat brain. Furthermore, we also report SiNPs-induced apoptosis in CS, through mitochondrial and ER stress-mediated signalling.

  1. Skeletal muscle transcriptional coactivator PGC-1α mediates mitochondrial, but not metabolic, changes during calorie restriction.

    Science.gov (United States)

    Finley, Lydia W S; Lee, Jaewon; Souza, Amanda; Desquiret-Dumas, Valérie; Bullock, Kevin; Rowe, Glenn C; Procaccio, Vincent; Clish, Clary B; Arany, Zoltan; Haigis, Marcia C

    2012-02-21

    Calorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation, and reactive oxygen species (ROS) scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1α is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1α activity. To test this model, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1α (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1α is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy (EM) demonstrated that PGC-1α is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1α is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1α nor mitochondrial biogenesis in skeletal muscle are required for the whole-body metabolic benefits of CR.

  2. Mechanism of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy)-mediated mitochondrial dysfunction in rat liver.

    Science.gov (United States)

    Moon, Kwan-Hoon; Upreti, Vijay V; Yu, Li-Rong; Lee, Insong J; Ye, Xiaoying; Eddington, Natalie D; Veenstra, Timothy D; Song, Byoung-Joon

    2008-09-01

    Despite numerous reports citing the acute hepatotoxicity caused by 3,4-methylenedioxymethamphetamine (MDMA) (ecstasy), the underlying mechanism of organ damage is poorly understood. We hypothesized that key mitochondrial proteins are oxidatively modified and inactivated in MDMA-exposed tissues. The aim of this study was to identify and investigate the mechanism of inactivation of oxidatively modified mitochondrial proteins, prior to the extensive mitochondrial dysfunction and liver damage following MDMA exposure. MDMA-treated rats showed abnormal liver histology with significant elevation in plasma transaminases, nitric oxide synthase, and the level of hydrogen peroxide. Oxidatively modified mitochondrial proteins in control and MDMA-exposed rats were labeled with biotin-N-maleimide (biotin-NM) as a sensitive probe for oxidized proteins, purified with streptavidin-agarose, and resolved using 2-DE. Comparative 2-DE analysis of biotin-NM-labeled proteins revealed markedly increased levels of oxidatively modified proteins following MDMA exposure. Mass spectrometric analysis identified oxidatively modified mitochondrial proteins involved in energy supply, fat metabolism, antioxidant defense, and chaperone activities. Among these, the activities of mitochondrial aldehyde dehydrogenase, 3-ketoacyl-CoA thiolases, and ATP synthase were significantly inhibited following MDMA exposure. Our data show for the first time that MDMA causes the oxidative inactivation of key mitochondrial enzymes which most likely contributes to mitochondrial dysfunction and subsequent liver damage in MDMA-exposed animals.

  3. Celastrol attenuates mitochondrial dysfunction and inflammation in palmitate-mediated insulin resistance in C3A hepatocytes.

    Science.gov (United States)

    Abu Bakar, Mohamad Hafizi; Sarmidi, Mohamad Roji; Tan, Joo Shun; Mohamad Rosdi, Mohamad Norisham

    2017-03-15

    Accumulating evidence indicates that mitochondrial dysfunction-induced inflammation is among the convergence points for the greatest hallmarks of hepatic insulin resistance. Celastrol, an anti-inflammatory compound from the root of Tripterygium Wilfordii has been reported to mitigate insulin resistance and inflammation in animal disease models. Nevertheless, the specific mechanistic actions of celastrol in modulating such improvements at the cellular level remain obscure. The present study sought to explore the mechanistic roles of celastrol upon insulin resistance induced by palmitate in C3A human hepatocytes. The hepatocytes exposed to palmitate (0.75mM) for 48h exhibited reduced both basal and insulin-stimulated glucose uptake, mitochondrial dysfunction, leading to increased mitochondrial oxidative stress with diminished fatty acid oxidation. Elevated expressions of nuclear factor-kappa B p65 (NF-κB p65), c-Jun NH(2)-terminal kinase (JNK) signaling pathways and the amplified release of pro-inflammatory cytokines including IL-8, IL-6, TNF-α and CRP were observed following palmitate treatment. Consistently, palmitate reduced and augmented phosphorylated Tyrosine-612 and Serine-307 of insulin receptor substrate-1 (IRS-1) proteins, respectively in hepatocytes. However, celastrol at the optimum concentration of 30nM was able to reverse these deleterious occasions and protected the cells from mitochondrial dysfunction and insulin resistance. Importantly, we presented evidence for the first time that celastrol efficiently prevented palmitate-induced insulin resistance in hepatocytes at least, via improved mitochondrial functions and insulin signaling pathways. In summary, the present investigation underlines a conceivable mechanism to elucidate the cytoprotective potential of celastrol in attenuating mitochondrial dysfunction and inflammation against the development of hepatic insulin resistance. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

    Directory of Open Access Journals (Sweden)

    Deepak Jain

    Full Text Available A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO were treated with multiple low doses of streptozotocin (MLDS to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.

  5. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death.

    Science.gov (United States)

    Jain, Deepak; Weber, Gesine; Eberhard, Daniel; Mehana, Amir E; Eglinger, Jan; Welters, Alena; Bartosinska, Barbara; Jeruschke, Kay; Weiss, Jürgen; Päth, Günter; Ariga, Hiroyoshi; Seufert, Jochen; Lammert, Eckhard

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflammatory beta cell stress and cell death. Subsequently, glucose tolerance tests were performed, and plasma insulin as well as fasting and random blood glucose concentrations were monitored. Mitochondrial morphology and number of insulin granules were quantified in beta cells. Moreover, islet cell damage was determined in vitro after streptozotocin and cytokine treatment of isolated wild type and DJ-1 KO islets using calcein AM/ethidium homodimer-1 staining and TUNEL staining. Compared to wild type mice, DJ-1 KO mice became diabetic following MLDS treatment. Insulin concentrations were substantially reduced, and fasting blood glucose concentrations were significantly higher in MLDS-treated DJ-1 KO mice compared to equally treated wild type mice. Rates of beta cell apoptosis upon MLDS treatment were twofold higher in DJ-1 KO mice compared to wild type mice, and in vitro inflammatory cytokines led to twice as much beta cell death in pancreatic islets from DJ-1 KO mice versus those of wild type mice. In conclusion, this study identified the anti-oxidant protein DJ-1 as being capable of protecting pancreatic islet cells from cell death induced by an inflammatory and cytotoxic setting.

  6. The homeobox protein CEH-23 mediates prolonged longevity in response to impaired mitochondrial electron transport chain in C. elegans.

    Directory of Open Access Journals (Sweden)

    Ludivine Walter

    2011-06-01

    Full Text Available Recent findings indicate that perturbations of the mitochondrial electron transport chain (METC can cause extended longevity in evolutionarily diverse organisms. To uncover the molecular basis of how altered METC increases lifespan in C. elegans, we performed an RNAi screen and revealed that three predicted transcription factors are specifically required for the extended longevity of mitochondrial mutants. In particular, we demonstrated that the nuclear homeobox protein CEH-23 uniquely mediates the longevity but not the slow development, reduced brood size, or resistance to oxidative stress associated with mitochondrial mutations. Furthermore, we showed that ceh-23 expression levels are responsive to altered METC, and enforced overexpression of ceh-23 is sufficient to extend lifespan in wild-type background. Our data point to mitochondria-to-nucleus communications to be key for longevity determination and highlight CEH-23 as a novel longevity factor capable of responding to mitochondrial perturbations. These findings provide a new paradigm for how mitochondria impact aging and age-dependent diseases.

  7. Mdm31 protein mediates sensitivity to potassium ionophores but does not regulate mitochondrial morphology or phospholipid trafficking in Schizosaccharomyces pombe.

    Science.gov (United States)

    Ivan, Branislav; Lajdova, Dana; Abelovska, Lenka; Balazova, Maria; Nosek, Jozef; Tomaska, Lubomir

    2015-03-01

    Mdm31p is an inner mitochondrial membrane (IMM) protein with unknown function in Saccharomyces cerevisiae. Mutants lacking Mdm31p contain only a few giant spherical mitochondria with disorganized internal structure, altered phospholipid composition and disturbed ion homeostasis, accompanied by increased resistance to the electroneutral K+ /H+ ionophore nigericin. These phenotypes are interpreted as resulting from diverse roles of Mdm31p, presumably in linking mitochondrial DNA (mtDNA) to the machinery involved in segregation of mitochondria, in mediating cation transport across IMM and in phospholipid shuttling between mitochondrial membranes. To investigate which of the roles of Mdm31p are conserved in ascomycetous yeasts, we analysed the Mdm31p orthologue in Schizosaccharomyces pombe. Our results demonstrate that, similarly to its S. cerevisiae counterpart, SpMdm31 is a mitochondrial protein and its absence results in increased resistance to nigericin. However, in contrast to S. cerevisiae, Sz. pombe cells lacking SpMdm31 are also less sensitive to the electrogenic K+ ionophore valinomycin. Moreover, mitochondria of the fission yeast mdm31Δ mutant display no changes in morphology or phospholipid composition. Therefore, in terms of function, the two orthologous proteins appear to have considerably diverged between these two evolutionarily distant yeast species, possibly sharing only their participation in ion homeostasis.

  8. IL-15 Mediates Mitochondrial Activity through a PPARδ-Dependent-PPARα-Independent Mechanism in Skeletal Muscle Cells

    Science.gov (United States)

    2016-01-01

    Molecular mediators of metabolic processes, to increase energy expenditure, have become a focus for therapies of obesity. The discovery of cytokines secreted from the skeletal muscle (SKM), termed “myokines,” has garnered attention due to their positive effects on metabolic processes. Interleukin-15 (IL-15) is a myokine that has numerous positive metabolic effects and is linked to the PPAR family of mitochondrial regulators. Here, we aimed to determine the importance of PPARα and/or PPARδ as targets of IL-15 signaling. C2C12 SKM cells were differentiated for 6 days and treated every other day with IL-15 (100 ng/mL), a PPARα inhibitor (GW-6471), a PPARδ inhibitor (GSK-3787), or both IL-15 and the inhibitors. IL-15 increased mitochondrial activity and induced PPARα, PPARδ, PGC1α, PGC1β, UCP2, and Nrf1 expression. There was no effect of inhibiting PPARα, in combination with IL-15, on the aforementioned mRNA levels except for PGC1β and Nrf1. However, with PPARδ inhibition, IL-15 failed to induce the expression levels of PGC1α, PGC1β, UCP2, and Nrf1. Further, inhibition of PPARδ abolished IL-15 induced increases in citrate synthase activity, ATP production, and overall mitochondrial activity. IL-15 had no effects on mitochondrial biogenesis. Our data indicates that PPARδ activity is required for the beneficial metabolic effects of IL-15 signaling in SKM.

  9. Synergistic inhibitory effect of nicotine plus oral contraceptive on mitochondrial complex-IV is mediated by estrogen receptor-β in female rats.

    Science.gov (United States)

    Raval, Ami P; Dave, Kunjan R; Saul, Isabel; Gonzalez, Gabriel J; Diaz, Francisca

    2012-04-01

    Chronic nicotine and oral contraceptive (NOC) exposure caused significant loss of hippocampal membrane-bound estrogen receptor-beta (ER-β) in female rats compared with exposure to nicotine alone. Mitochondrial ER-β regulates estrogen-mediated mitochondrial structure and function; therefore, investigating the impact of NOC on mitochondrial ER-β and its function could help delineate the harmful synergism between nicotine and OC. In this study, we tested the hypothesis that NOC-induced loss of mitochondrial ER-β alters the oxidative phosphorylation system protein levels and mitochondrial respiratory function. This hypothesis was tested in hippocampal mitochondria isolated from female rats exposed to saline, nicotine, OC or NOC for 16 days. NOC decreased the mitochondrial ER-β protein levels and reduced oxygen consumption and complex IV (CIV) activity by 34% and 26% compared with saline- or nicotine-administered groups, respectively. We also observed significantly low protein levels of all mitochondrial-encoded CIV subunits after NOC as compared with the nicotine or saline groups. Similarly, the silencing of ER-β reduced the phosphorylation of cyclic-AMP response element binding protein, and also reduced levels of CIV mitochondrial-encoded subunits after estrogen stimulation. Overall, these results suggest that mitochondrial ER-β loss is responsible for mitochondrial malfunction after NOC.

  10. Apigenin Protects Endothelial Cells from Lipopolysaccharide (LPS)-Induced Inflammation by Decreasing Caspase-3 Activation and Modulating Mitochondrial Function

    Science.gov (United States)

    Duarte, Silvia; Arango, Daniel; Parihar, Arti; Hamel, Patrice; Yasmeen, Rumana; Doseff, Andrea I.

    2013-01-01

    Acute and chronic inflammation is characterized by increased reactive oxygen species (ROS) production, dysregulation of mitochondrial metabolism and abnormal immune function contributing to cardiovascular diseases and sepsis. Clinical and epidemiological studies suggest potential beneficial effects of dietary interventions in inflammatory diseases but understanding of how nutrients work remains insufficient. In the present study, we evaluated the effects of apigenin, an anti-inflammatory flavonoid abundantly found in our diet, in endothelial cells during inflammation. Here, we show that apigenin reduced lipopolysaccharide (LPS)-induced apoptosis by decreasing ROS production and the activity of caspase-3 in endothelial cells. Apigenin conferred protection against LPS-induced mitochondrial dysfunction and reestablished normal mitochondrial complex I activity, a major site of electron leakage and superoxide production, suggesting its ability to modulate endothelial cell metabolic function during inflammation. Collectively, these findings indicate that the dietary compound apigenin stabilizes mitochondrial function during inflammation preventing endothelial cell damage and thus provide new translational opportunities for the use of dietary components in the prevention and treatment of inflammatory diseases. PMID:23989609

  11. Small Molecule Inhibitors of Cyclophilin D To Protect Mitochondrial Function as a Potential Treatment for Acute Pancreatitis.

    Science.gov (United States)

    Shore, Emma R; Awais, Muhammad; Kershaw, Neil M; Gibson, Robert R; Pandalaneni, Sravan; Latawiec, Diane; Wen, Li; Javed, Muhammad A; Criddle, David N; Berry, Neil; O'Neill, Paul M; Lian, Lu-Yun; Sutton, Robert

    2016-03-24

    Opening of the mitochondrial permeability transition pore (MPTP) causes mitochondrial dysfunction and necrosis in acute pancreatitis (AP), a condition without specific drug treatment. Cyclophilin D (CypD) is a mitochondrial matrix peptidyl-prolyl isomerase that regulates the MPTP and is a drug target for AP. We have synthesized urea-based small molecule inhibitors of cyclophilins and tested them against CypD using binding and isomerase activity assays. Thermodynamic profiles of the CypD/inhibitor interactions were determined by isothermal titration calorimetry. Seven new high-resolution crystal structures of CypD-inhibitor complexes were obtained to guide compound optimization. Compounds 4, 13, 14, and 19 were tested in freshly isolated murine pancreatic acinar cells (PACs) to determine inhibition of toxin-induced loss of mitochondrial membrane potential (ΔΨm) and necrotic cell death pathway activation. Compound 19 was found to have a Kd of 410 nM and a favorable thermodynamic profile, and it showed significant protection of ΔΨm and reduced necrosis of murine as well as human PACs. Compound 19 holds significant promise for future lead optimization.

  12. Oxidative stress induced by palytoxin in human keratinocytes is mediated by a H{sup +}-dependent mitochondrial pathway

    Energy Technology Data Exchange (ETDEWEB)

    Pelin, Marco, E-mail: marco.pelin@phd.units.it [Department of Life Science, University of Trieste, Via L. Giorgieri 7/9, 34127 Trieste (Italy); Ponti, Cristina, E-mail: cponti@units.it [Department of Life Science, University of Trieste, Via L. Giorgieri 7/9, 34127 Trieste (Italy); Sosa, Silvio, E-mail: silvio.sosa@econ.units.it [Department of Life Science, University of Trieste, Via L. Giorgieri 7/9, 34127 Trieste (Italy); Gibellini, Davide, E-mail: davide.gibellini@unibo.it [Department of Haematology and Oncological Sciences, University of Bologna, Via Massarenti 9, 40138 Bologna (Italy); Florio, Chiara, E-mail: florioc@units.it [Department of Life Science, University of Trieste, Via L. Giorgieri 7/9, 34127 Trieste (Italy); Tubaro, Aurelia, E-mail: tubaro@units.it [Department of Life Science, University of Trieste, Via L. Giorgieri 7/9, 34127 Trieste (Italy)

    2013-01-01

    In the last decades, massive blooms of palytoxin (PLTX)-producing Ostreopsis cf. ovata have been observed along Mediterranean coasts, usually associated to human respiratory and cutaneous problems. At the molecular level, PLTX induces a massive intracellular Na{sup +} influx due to the transformation of Na{sup +}/K{sup +} ATPase in a cationic channel. Recently, we have demonstrated that Na{sup +} overload is the crucial step in mediating overproduction of reactive oxygen species (ROS) and cell death in human HaCaT keratinocytes, tentatively explaining PLTX-induced skin irritant effects. In the present study the molecular mechanisms of ROS production induced by PLTX-mediated Na{sup +} intracellular overload have been investigated. In HaCaT cells, PLTX exposure caused accumulation of superoxide anion, but not of nitric oxide or peroxynitrite/hydroxyl radicals. Even if RT-PCR and western blot analysis revealed an early NOX-2 and iNOS gene and protein over-expressions, their active involvement seemed to be only partial since selective inhibitors did not completely reduce O{sub 2}{sup −} production. A significant role of other enzymes (COX-1, COX-2, XO) was not evidenced. Nigericin, that counteracts Na{sup +}-mediated H{sup +}-imbalance, dissipating ΔpH across mitochondrial inner membrane, and the uncouplers DNP significantly reduced O{sub 2}{sup −} production. These inhibitions were synergistic when co-exposed with complex-I inhibitor rotenone. These results suggest a novel mechanism of O{sub 2}{sup −} production induced by PLTX-mediated ionic imbalance. Indeed, the H{sup +} intracellular overload that follows PLTX-induced intracellular Na{sup +} accumulation, could enhance ΔpH across mitochondrial inner membrane, that seems to be the driving force for O{sub 2}{sup −} production by reversing mitochondrial electron transport. Highlights: ► PLTX induces superoxide (O{sub 2}{sup −}) production by reversing mitochondrial transport chain. ► The mechanism of

  13. The mitochondrial fatty acid synthesis (mtFASII) pathway is capable of mediating nuclear-mitochondrial cross talk through the PPAR system of transcriptional activation

    Energy Technology Data Exchange (ETDEWEB)

    Parl, Angelika; Mitchell, Sabrina L.; Clay, Hayley B.; Reiss, Sara; Li, Zhen; Murdock, Deborah G., E-mail: deborah.murdock@vanderbilt.edu

    2013-11-15

    Highlights: •The function of the mitochondria fatty acid synthesis pathway is partially unknown. •Overexpression of the pathway causes transcriptional activation through PPARs. •Knock down of the pathway attenuates that activation. •The last enzyme in the pathway regulates its own transcription. •Products of the mtFASII pathway are able to drive nuclear transcription. -- Abstract: Mammalian cells contain two fatty acid synthesis pathways, the cytosolic FASI pathway, and the mitochondrial FASII pathway. The selection behind the conservation of the mitochondrial pathway is not completely understood, given the presence of the cytosolic FAS pathway. In this study, we show through heterologous gene reporter systems and PCR-based arrays that overexpression of MECR, the last step in the mtFASII pathway, causes modulation of gene expression through the PPAR pathway. Electromobility shift assays (EMSAs) demonstrate that overexpression of MECR causes increased binding of PPARs to DNA, while cell fractionation and imaging studies show that MECR remains localized to the mitochondria. Interestingly, knock down of the mtFASII pathway lessens the effect of MECR on this transcriptional modulation. Our data are most consistent with MECR-mediated transcriptional activation through products of the mtFASII pathway, although we cannot rule out MECR acting as a coactivator. Further investigation into the physiological relevance of this communication will be necessary to better understand some of the phenotypic consequences of deficits in this pathway observed in animal models and human disease.

  14. The mitochondrial fatty acid synthesis (mtFASII) pathway is capable of mediating nuclear-mitochondrial cross talk through the PPAR system of transcriptional activation.

    Science.gov (United States)

    Parl, Angelika; Mitchell, Sabrina L; Clay, Hayley B; Reiss, Sara; Li, Zhen; Murdock, Deborah G

    2013-11-15

    Mammalian cells contain two fatty acid synthesis pathways, the cytosolic FASI pathway, and the mitochondrial FASII pathway. The selection behind the conservation of the mitochondrial pathway is not completely understood, given the presence of the cytosolic FAS pathway. In this study, we show through heterologous gene reporter systems and PCR-based arrays that overexpression of MECR, the last step in the mtFASII pathway, causes modulation of gene expression through the PPAR pathway. Electromobility shift assays (EMSAs) demonstrate that overexpression of MECR causes increased binding of PPARs to DNA, while cell fractionation and imaging studies show that MECR remains localized to the mitochondria. Interestingly, knock down of the mtFASII pathway lessens the effect of MECR on this transcriptional modulation. Our data are most consistent with MECR-mediated transcriptional activation through products of the mtFASII pathway, although we cannot rule out MECR acting as a coactivator. Further investigation into the physiological relevance of this communication will be necessary to better understand some of the phenotypic consequences of deficits in this pathway observed in animal models and human disease.

  15. Mitochondrial DNA variants mediate energy production and expression levels for CFH, C3 and EFEMP1 genes: implications for age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    M Cristina Kenney

    Full Text Available BACKGROUND: Mitochondrial dysfunction is associated with the development and progression of age-related macular degeneration (AMD. Recent studies using populations from the United States and Australia have demonstrated that AMD is associated with mitochondrial (mt DNA haplogroups (as defined by combinations of mtDNA polymorphisms that represent Northern European Caucasians. The aim of this study was to use the cytoplasmic hybrid (cybrid model to investigate the molecular and biological functional consequences that occur when comparing the mtDNA H haplogroup (protective for AMD versus J haplogroup (high risk for AMD. METHODOLOGY/PRINCIPAL FINDINGS: Cybrids were created by introducing mitochondria from individuals with either H or J haplogroups into a human retinal epithelial cell line (ARPE-19 that was devoid of mitochondrial DNA (Rho0. In cybrid lines, all of the cells carry the same nuclear genes but vary in mtDNA content. The J cybrids had significantly lower levels of ATP and reactive oxygen/nitrogen species production, but increased lactate levels and rates of growth. Q-PCR analyses showed J cybrids had decreased expressions for CFH, C3, and EFEMP1 genes, high risk genes for AMD, and higher expression for MYO7A, a gene associated with retinal degeneration in Usher type IB syndrome. The H and J cybrids also have comparatively altered expression of nuclear genes involved in pathways for cell signaling, inflammation, and metabolism. CONCLUSION/SIGNIFICANCE: Our findings demonstrate that mtDNA haplogroup variants mediate not only energy production and cell growth, but also cell signaling for major molecular pathways. These data support the hypothesis that mtDNA variants play important roles in numerous cellular functions and disease processes, including AMD.

  16. Mitochondrially mediated plasticity in the pathophysiology and treatment of bipolar disorder.

    Science.gov (United States)

    Quiroz, Jorge A; Gray, Neil A; Kato, Tadafumi; Manji, Husseini K

    2008-10-01

    Bipolar disorder (BPD) has traditionally been conceptualized as a neurochemical disorder, but there is mounting evidence for impairments of cellular plasticity and resilience. Here, we review and synthesize the evidence that critical aspects of mitochondrial function may play an integral role in the pathophysiology and treatment of BPD. Retrospective database searches were performed, including MEDLINE, abstract booklets, and conference proceedings. Articles were also obtained from references therein and personal communications, including original scientific work, reviews, and meta-analyses of the literature. Material regarding the potential role of mitochondrial function included genetic studies, microarray studies, studies of intracellular calcium regulation, neuroimaging studies, postmortem brain studies, and preclinical and clinical studies of cellular plasticity and resilience. We review these data and discuss their implications not only in the context of changing existing conceptualizations regarding the pathophysiology of BPD, but also for the strategic development of improved therapeutics. We have focused on specific aspects of mitochondrial dysfunction that may have major relevance for the pathophysiology and treatment of BPD. Notably, we discuss calcium dysregulation, oxidative phosphorylation abnormalities, and abnormalities in cellular resilience and synaptic plasticity. Accumulating evidence from microarray studies, biochemical studies, neuroimaging, and postmortem brain studies all support the role of mitochondrial dysfunction in the pathophysiology of BPD. We propose that although BPD is not a classic mitochondrial disease, subtle deficits in mitochondrial function likely play an important role in various facets of BPD, and that enhancing mitochondrial function may represent a critical component for the optimal long-term treatment of the disorder.

  17. Estrogen protects neuronal cells from amyloid beta-induced apoptosis via regulation of mitochondrial proteins and function

    Directory of Open Access Journals (Sweden)

    Iwamoto Sean

    2006-11-01

    Full Text Available Abstract Background Neurodegeneration in Alzheimer's disease is associated with increased apoptosis and parallels increased levels of amyloid beta, which can induce neuronal apoptosis. Estrogen exposure prior to neurotoxic insult of hippocampal neurons promotes neuronal defence and survival against neurodegenerative insults including amyloid beta. Although all underlying molecular mechanisms of amyloid beta neurotoxicity remain undetermined, mitochondrial dysfunction, including altered calcium homeostasis and Bcl-2 expression, are involved in neurodegenerative vulnerability. Results In this study, we investigated the mechanism of 17β-estradiol-induced prevention of amyloid beta-induced apoptosis of rat hippocampal neuronal cultures. Estradiol treatment prior to amyloid beta exposure significantly reduced the number of apoptotic neurons and the associated rise in resting intracellular calcium levels. Amyloid beta exposure provoked down regulation of a key antiapoptotic protein, Bcl-2, and resulted in mitochondrial translocation of Bax, a protein known to promote cell death, and subsequent release of cytochrome c. E2 pretreatment inhibited the amyloid beta-induced decrease in Bcl-2 expression, translocation of Bax to the mitochondria and subsequent release of cytochrome c. Further implicating the mitochondria as a target of estradiol action, in vivo estradiol treatment enhanced the respiratory function of whole brain mitochondria. In addition, estradiol pretreatment protected isolated mitochondria against calcium-induced loss of respiratory function. Conclusion Therefore, we propose that estradiol pretreatment protects against amyloid beta neurotoxicity by limiting mitochondrial dysfunction via activation of antiapoptotic mechanisms.

  18. The Protective Effects of Salidroside from Exhaustive Exercise-Induced Heart Injury by Enhancing the PGC-1 α -NRF1/NRF2 Pathway and Mitochondrial Respiratory Function in Rats

    National Research Council Canada - National Science Library

    Ping, Zheng; Zhang, Long-fei; Cui, Yu-juan; Chang, Yu-mei; Jiang, Cai-wu; Meng, Zhen-zhi; Xu, Peng; Liu, Hai-yan; Wang, Dong-ying; Cao, Xue-bin

    2015-01-01

    To test the hypothesis that salidroside (SAL) can protect heart from exhaustive exercise-induced injury by enhancing mitochondrial respiratory function and mitochondrial biogenesis key signaling pathway PGC-1α-NRF1/NRF2 in rats...

  19. Singly protonated dehydronorcantharidin silver coordination polymer induces apoptosis of lung cancer cells via reactive oxygen species-mediated mitochondrial pathway.

    Science.gov (United States)

    Li, Senpeng; Zhang, Shuo; Jin, Xing; Tan, Xuejie; Lou, Jianfang; Zhang, Xiumei; Zhao, Yunxue

    2014-10-30

    Silver complexes have been shown to possess antimicrobial and anticancer properties. Ag-SP-DNC, a novel silver and singly protonated dehydronorcantharidin complex, was synthesized in our previous study. In this study, we offer evidence that Ag-SP-DNC elicits a reactive oxygen species (ROS)-mediated mitochondrial apoptosis in lung cancer cells. Ag-SP-DNC inhibited the growth of A549 cells by inducing G2/M phase cell cycle arrest and apoptosis. Ag-SP-DNC induced apoptosis was associated with the levels of intracellular ROS. The further study revealed that Ag-SP-DNC disrupted the mitochondrial membrane potential, induced the caspase-3 activation and led to the translocation of apoptosis inducing factor and endonucleaseG to the nucleus. These findings have important implications for the development of silver complexes for anticancer applications.

  20. Protective effects of arachidonic acid against palmitic acid-mediated lipotoxicity in HIT-T15 cells.

    Science.gov (United States)

    Cho, Young Sik; Kim, Chi Hyun; Kim, Ki Young; Cheon, Hyae Gyeong

    2012-05-01

    Saturated fatty acids have been considered major contributing factors in type 2 diabetes, whereas unsaturated fatty acids have beneficial effects for preventing the development of diabetes. However, the effects of polyunsaturated fatty acids in pancreatic β cells have not been reported. Here, we examined the effects of arachidonic acid (AA) on palmitic acid (PA)-mediated lipotoxicity in clonal HIT-T15 pancreatic β cells. AA prevented the PA-induced lipotoxicity as indicated by cell viability, DNA fragmentation and mitochondrial membrane potential, whereas eicosatetraynoic acid (ETYA), a non-metabolizable AA, had little effect on PA-induced lipotoxicity. In parallel with its protective effects against PA-induced lipotoxicity, AA restored impaired insulin expression and secretion induced by PA. AA but not ETYA increased intracellular triglyceride (TG) in the presence of PA compared with PA alone, and xanthohumol, a diacylglycerol acyltransferase (DGAT) inhibitor, reversed AA-induced protection from PA. Taken together, our results suggest that AA protects against PA-induced lipotoxicity in clonal HIT-T15 pancreatic β cells, and the protective effects may be associated with TG accumulation, possibly through sequestration of lipotoxic PA into TG.

  1. Geniposide Alleviates Amyloid-Induced Synaptic Injury by Protecting Axonal Mitochondrial Trafficking

    Science.gov (United States)

    Zhang, Haijing; Zhao, Chunhui; Lv, Cui; Liu, Xiaoli; Du, Shijing; Li, Zhi; Wang, Yongyan; Zhang, Wensheng

    2017-01-01

    Synaptic and mitochondrial pathologies are early events in the progression of Alzheimer's disease (AD). Normal axonal mitochondrial function and transport play crucial roles in maintaining synaptic function by producing high levels of adenosine triphosphate and buffering calcium. However, there can be abnormal axonal mitochondrial trafficking, distribution, and fragmentation, which are strongly correlated with amyloid-β (Aβ)-induced synaptic loss and dysfunction. The present study examined the neuroprotective effect of geniposide, a compound extracted from gardenia fruit in Aβ-treated neurons and an AD mouse model. Geniposide alleviated Aβ-induced axonal mitochondrial abnormalities by increasing axonal mitochondrial density and length and improving mitochondrial motility and trafficking in cultured hippocampal neurons, consequently ameliorating synaptic damage by reversing synaptic loss, addressing spine density and morphology abnormalities, and ameliorating the decreases in synapse-related proteins in neurons and APPswe/PS1dE9 mice. These findings provide new insights into the effects of geniposide administration on neuronal and synaptic functions under conditions of Aβ enrichment. PMID:28179878

  2. Heat Killed Attenuated Leishmania Induces Apoptosis of HepG2 Cells Through ROS Mediated p53 Dependent Mitochondrial Pathway

    Directory of Open Access Journals (Sweden)

    Dipayan Bose

    2016-03-01

    Full Text Available Background/Aims: Cytotoxic effect of attenuated Leishmania on liver cancer cells by inducing ROS generation. Methods: Spectrophotometric study to analyze cell death and levels of different active caspases. Flow cytometric study was done to analyze apoptosis induction and ROS generation and levels of different protein. Western blot analysis was performed to study the levels of protein. Confocal microscopy was done to ascertain the expression of different apoptotic markers. Results: We have now observed that attenuated Leishmania donovani UR6 also has potentiality towards growth inhibition of HepG2 cells and investigated the mechanism of action. The effect is associated with increased DNA fragmentation, rise in number of annexinV positive cells, and cell cycle arrest at G1 phase. The detection of unregulated levels of active PARP, cleaved caspases 3 and 9, cytosolic cytochrome C, Bax, and Bad, along with the observed downregulation of Bcl-2 and loss of mitochondrial membrane potential suggested the involvement of mitochondrial pathway. Enhanced ROS and p53 levels regulate the apoptosis of HepG2 cells. NAC was found to inhibit p53 production but PFT-α has no effect on ROS generation. In conclusion, Leishmania donovani UR6 efficiently induces apoptosis in HepG2 cells through ROS mediated p53 dependent mitochondrial pathway. Conclusion: It has been reported earlier that some parasites show prominent cytotoxic effect and prevent tumor growth. From our study we found that Leishmania donovani UR6 efficiently induced apoptosis in HepG2 cells through ROS mediated p53 dependent mitochondrial pathway. This study has rejuvenated the age old idea of bio-therapy.

  3. Protection against acetaminophen-induced liver injury by allopurinol is dependent on aldehyde oxidase-mediated liver preconditioning.

    Science.gov (United States)

    Williams, C David; McGill, Mitchell R; Lebofsky, Margitta; Bajt, Mary Lynn; Jaeschke, Hartmut

    2014-02-01

    Acetaminophen (APAP) overdose causes severe and occasionally fatal liver injury. Numerous drugs that attenuate APAP toxicity have been described. However these compounds frequently protect by cytochrome P450 inhibition, thereby preventing the initiating step of toxicity. We have previously shown that pretreatment with allopurinol can effectively protect against APAP toxicity, but the mechanism remains unclear. In the current study, C3HeB/FeJ mice were administered allopurinol 18h or 1h prior to an APAP overdose. Administration of allopurinol 18h prior to APAP overdose resulted in an 88% reduction in liver injury (serum ALT) 6h after APAP; however, 1h pretreatment offered no protection. APAP-cysteine adducts and glutathione depletion kinetics were similar with or without allopurinol pretreatment. The phosphorylation and mitochondrial translocation of c-jun-N-terminal-kinase (JNK) have been implicated in the progression of APAP toxicity. In our study we showed equivalent early JNK activation (2h) however late JNK activation (6h) was attenuated in allopurinol treated mice, which suggests that later JNK activation is more critical for the toxicity. Additional mice were administered oxypurinol (primary metabolite of allopurinol) 18h or 1h pre-APAP, but neither treatment protected. This finding implicated an aldehyde oxidase (AO)-mediated metabolism of allopurinol, so mice were treated with hydralazine to inhibit AO prior to allopurinol/APAP administration, which eliminated the protective effects of allopurinol. We evaluated potential targets of AO-mediated preconditioning and found increased hepatic metallothionein 18h post-allopurinol. These data show metabolism of allopurinol occurring independent of P450 isoenzymes preconditions the liver and renders the animal less susceptible to an APAP overdose.

  4. Protective effect of Boerhaavia diffusa L. against mitochondrial dysfunction in angiotensin II induced hypertrophy in H9c2 cardiomyoblast cells.

    Directory of Open Access Journals (Sweden)

    Ayyappan Prathapan

    Full Text Available Mitochondrial dysfunction plays a critical role in the development of cardiac hypertrophy and heart failure. So mitochondria are emerging as one of the important druggable targets in the management of cardiac hypertrophy and other associated complications. In the present study, effects of ethanolic extract of Boerhaavia diffusa (BDE, a green leafy vegetable against mitochondrial dysfunction in angiotensin II (Ang II induced hypertrophy in H9c2 cardiomyoblasts was evaluated. H9c2 cells challenged with Ang II exhibited pathological hypertrophic responses and mitochondrial dysfunction which was evident from increment in cell volume (49.09±1.13%, protein content (55.17±1.19%, LDH leakage (58.74±1.87%, increased intracellular ROS production (26.25±0.91%, mitochondrial superoxide generation (65.06±2.27%, alteration in mitochondrial transmembrane potential (ΔΨm, opening of mitochondrial permeability transition pore (mPTP and mitochondrial swelling. In addition, activities of mitochondrial respiratory chain complexes (I-IV, aconitase, NADPH oxidase, thioredoxin reductase, oxygen consumption rate and calcium homeostasis were evaluated. Treatment with BDE significantly prevented the generation of intracellular ROS and mitochondrial superoxide radicals and protected the mitochondria by preventing dissipation of ΔΨm, opening of mPTP, mitochondrial swelling and enhanced the activities of respiratory chain complexes and oxygen consumption rate in H9c2 cells. Activities of aconitase and thioredoxin reductase which was lowered (33.77±0.68% & 45.81±0.71% respectively due to hypertrophy, were increased in BDE treated cells (P≤0.05. Moreover, BDE also reduced the intracellular calcium overload in Ang II treated cells. Overall results revealed the protective effects of B. diffusa against mitochondrial dysfunction in hypertrophy in H9c2 cells and the present findings may shed new light on the therapeutic potential of B. diffusa in addition to its

  5. Lost region in amyloid precursor protein (APP) through TALEN-mediated genome editing alters mitochondrial morphology.

    Science.gov (United States)

    Wang, Yajie; Wu, Fengyi; Pan, Haining; Zheng, Wenzhong; Feng, Chi; Wang, Yunfu; Deng, Zixin; Wang, Lianrong; Luo, Jie; Chen, Shi

    2016-02-29

    Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) deposition in the brain. Aβ plaques are produced through sequential β/γ cleavage of amyloid precursor protein (APP), of which there are three main APP isoforms: APP695, APP751 and APP770. KPI-APPs (APP751 and APP770) are known to be elevated in AD, but the reason remains unclear. Transcription activator-like (TAL) effector nucleases (TALENs) induce mutations with high efficiency at specific genomic loci, and it is thus possible to knock out specific regions using TALENs. In this study, we designed and expressed TALENs specific for the C-terminus of APP in HeLa cells, in which KPI-APPs are predominantly expressed. The KPI-APP mutants lack a 12-aa region that encompasses a 5-aa trans-membrane (TM) region and 7-aa juxta-membrane (JM) region. The mutated KPI-APPs exhibited decreased mitochondrial localization. In addition, mitochondrial morphology was altered, resulting in an increase in spherical mitochondria in the mutant cells through the disruption of the balance between fission and fusion. Mitochondrial dysfunction, including decreased ATP levels, disrupted mitochondrial membrane potential, increased ROS generation and impaired mitochondrial dehydrogenase activity, was also found. These results suggest that specific regions of KPI-APPs are important for mitochondrial localization and function.

  6. Early eradication of persistent Salmonella infection primes antibody-mediated protective immunity to recurrent infection.

    Science.gov (United States)

    Johanns, Tanner M; Law, Calvin Y; Kalekar, Lokeshchandra A; O'Donnell, Hope; Ertelt, James M; Rowe, Jared H; Way, Sing Sing

    2011-04-01

    Typhoid fever is a systemic, persistent infection caused by host-specific strains of Salmonella. Although the use of antibiotics has reduced the complications associated with primary infection, recurrent infection remains an important cause of ongoing human morbidity and mortality. Herein, we investigated the impacts of antibiotic eradication of primary infection on protection against secondary recurrent infection. Using a murine model of persistent Salmonella infection, we demonstrate protection against recurrent infection is sustained despite early eradication of primary infection. In this model, protection is not mediated by CD4(+) or CD8(+) T cells because depletion of these cells either alone or in combination prior to rechallenge does not abrogate protection. Instead, infection followed by antibiotic-mediated clearance primes robust levels of Salmonella-specific antibody that can adoptively transfer protection to naïve mice. Thus, eradication of persistent Salmonella infection primes antibody-mediated protective immunity to recurrent infection.

  7. Role of reactive oxygen species-mediated mitochondrial dysregulation in 3-bromopyruvate induced cell death in hepatoma cells : ROS-mediated cell death by 3-BrPA.

    Science.gov (United States)

    Kim, Ji Su; Ahn, Keun Jae; Kim, Jeong-Ah; Kim, Hye Mi; Lee, Jong Doo; Lee, Jae Myun; Kim, Se Jong; Park, Jeon Han

    2008-12-01

    Hexokinase type II (HK II) is the key enzyme for maintaining increased glycolysis in cancer cells where it is overexpressed. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, induces cell death in cancer cells. To elucidate the molecular mechanism of 3-BrPA-induced cell death, we used the hepatoma cell lines SNU449 (low expression of HKII) and Hep3B (high expression of HKII). 3-BrPA induced ATP depletion-dependent necrosis and apoptosis in both cell lines. 3-BrPA increased intracellular reactive oxygen species (ROS) leading to mitochondrial dysregulation. NAC (N-acetyl-L: -cysteine), an antioxidant, blocked 3-BrPA-induced ROS production, loss of mitochondrial membrane potential and cell death. 3-BrPA-mediated oxidative stress not only activated poly-ADP-ribose (PAR) but also translocated AIF from the mitochondria to the nucleus. Taken together, 3-BrPA induced ATP depletion-dependent necrosis and apoptosis and mitochondrial dysregulation due to ROS production are involved in 3-BrPA-induced cell death in hepatoma cells.

  8. A neuronal model of Alzheimer's disease: an insight into the mechanisms of oxidative stress-mediated mitochondrial injury.

    Science.gov (United States)

    Sompol, P; Ittarat, W; Tangpong, J; Chen, Y; Doubinskaia, I; Batinic-Haberle, I; Abdul, H M; Butterfield, D A; St Clair, D K

    2008-04-22

    Alzheimer's disease (AD) is associated with beta-amyloid accumulation, oxidative stress and mitochondrial dysfunction. However, the effects of genetic mutation of AD on oxidative status and mitochondrial manganese superoxide dismutase (MnSOD) production during neuronal development are unclear. To investigate the consequences of genetic mutation of AD on oxidative damages and production of MnSOD during neuronal development, we used primary neurons from new born wild-type (WT/WT) and amyloid precursor protein (APP) (NLh/NLh) and presenilin 1 (PS1) (P264L) knock-in mice (APP/PS1) which incorporated humanized mutations in the genome. Increasing levels of oxidative damages, including protein carbonyl, 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT), were accompanied by a reduction in mitochondrial membrane potential in both developing and mature APP/PS1 neurons compared with WT/WT neurons suggesting mitochondrial dysfunction under oxidative stress. Interestingly, developing APP/PS1 neurons were significantly more resistant to beta-amyloid 1-42 treatment, whereas mature APP/PS1 neurons were more vulnerable than WT/WT neurons of the same age. Consistent with the protective function of MnSOD, developing APP/PS1 neurons have increased MnSOD protein and activity, indicating an adaptive response to oxidative stress in developing neurons. In contrast, mature APP/PS1 neurons exhibited lower MnSOD levels compared with mature WT/WT neurons indicating that mature APP/PS1 neurons lost the adaptive response. Moreover, mature APP/PS1 neurons had more co-localization of MnSOD with nitrotyrosine indicating a greater inhibition of MnSOD by nitrotyrosine. Overexpression of MnSOD or addition of MnTE-2-PyP(5+) (SOD mimetic) protected against beta-amyloid-induced neuronal death and improved mitochondrial respiratory function. Together, the results demonstrate that compensatory induction of MnSOD in response to an early increase in oxidative stress protects developing neurons against

  9. Protection against acetaminophen-induced liver injury by allopurinol is dependent on aldehyde oxidase-mediated liver preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Williams, C. David; McGill, Mitchell R.; Lebofsky, Margitta; Bajt, Mary Lynn; Jaeschke, Hartmut, E-mail: hjaeschke@kumc.edu

    2014-02-01

    Acetaminophen (APAP) overdose causes severe and occasionally fatal liver injury. Numerous drugs that attenuate APAP toxicity have been described. However these compounds frequently protect by cytochrome P450 inhibition, thereby preventing the initiating step of toxicity. We have previously shown that pretreatment with allopurinol can effectively protect against APAP toxicity, but the mechanism remains unclear. In the current study, C3HeB/FeJ mice were administered allopurinol 18 h or 1 h prior to an APAP overdose. Administration of allopurinol 18 h prior to APAP overdose resulted in an 88% reduction in liver injury (serum ALT) 6 h after APAP; however, 1 h pretreatment offered no protection. APAP-cysteine adducts and glutathione depletion kinetics were similar with or without allopurinol pretreatment. The phosphorylation and mitochondrial translocation of c-jun-N-terminal-kinase (JNK) have been implicated in the progression of APAP toxicity. In our study we showed equivalent early JNK activation (2 h) however late JNK activation (6 h) was attenuated in allopurinol treated mice, which suggests that later JNK activation is more critical for the toxicity. Additional mice were administered oxypurinol (primary metabolite of allopurinol) 18 h or 1 h pre-APAP, but neither treatment protected. This finding implicated an aldehyde oxidase (AO)-mediated metabolism of allopurinol, so mice were treated with hydralazine to inhibit AO prior to allopurinol/APAP administration, which eliminated the protective effects of allopurinol. We evaluated potential targets of AO-mediated preconditioning and found increased hepatic metallothionein 18 h post-allopurinol. These data show metabolism of allopurinol occurring independent of P450 isoenzymes preconditions the liver and renders the animal less susceptible to an APAP overdose. - Highlights: • 18 h allopurinol pretreatment protects against acetaminophen-induced liver injury. • 1 h allopurinol pretreatment does not protect from APAP

  10. Cannabidiol Protects against Doxorubicin-Induced Cardiomyopathy by Modulating Mitochondrial Function and Biogenesis.

    Science.gov (United States)

    Hao, Enkui; Mukhopadhyay, Partha; Cao, Zongxian; Erdélyi, Katalin; Holovac, Eileen; Liaudet, Lucas; Lee, Wen-Shin; Haskó, György; Mechoulam, Raphael; Pacher, Pál

    2015-01-06

    Doxorubicin (DOX) is a widely used, potent chemotherapeutic agent; however, its clinical application is limited because of its dose-dependent cardiotoxicity. DOX's cardiotoxicity involves increased oxidative/nitrative stress, impaired mitochondrial function in cardiomyocytes/endothelial cells and cell death. Cannabidiol (CBD) is a nonpsychotropic constituent of marijuana, which is well tolerated in humans, with antioxidant, antiinflammatory and recently discovered antitumor properties. We aimed to explore the effects of CBD in a well-established mouse model of DOX-induced cardiomyopathy. DOX-induced cardiomyopathy was characterized by increased myocardial injury (elevated serum creatine kinase and lactate dehydrogenase levels), myocardial oxidative and nitrative stress (decreased total glutathione content and glutathione peroxidase 1 activity, increased lipid peroxidation, 3-nitrotyrosine formation and expression of inducible nitric oxide synthase mRNA), myocardial cell death (apoptotic and poly[ADP]-ribose polymerase 1 [PARP]-dependent) and cardiac dysfunction (decline in ejection fraction and left ventricular fractional shortening). DOX also impaired myocardial mitochondrial biogenesis (decreased mitochondrial copy number, mRNA expression of peroxisome proliferator-activated receptor γ coactivator 1-alpha, peroxisome proliferator-activated receptor alpha, estrogen-related receptor alpha), reduced mitochondrial function (attenuated complex I and II activities) and decreased myocardial expression of uncoupling protein 2 and 3 and medium-chain acyl-CoA dehydrogenase mRNA. Treatment with CBD markedly improved DOX-induced cardiac dysfunction, oxidative/nitrative stress and cell death. CBD also enhanced the DOX-induced impaired cardiac mitochondrial function and biogenesis. These data suggest that CBD may represent a novel cardioprotective strategy against DOX-induced cardiotoxicity, and the above-described effects on mitochondrial function and biogenesis may

  11. Protective Roles of α-lipoic Acid in Rat Model of Mitochondrial DNA4834bp Deletion in Inner Ear

    Institute of Scientific and Technical Information of China (English)

    彭炜; 胡钰娟; 钟毅; 陈蓓; 孙宇; 杨阳; 孔维佳

    2010-01-01

    The protective roles of α-lipoic acid in the rat model of mitochondrial DNA (mtDNA) 4834bp deletion in inner ear were investigated. Forty female Wistar rats at 4 weeks of age were divided into four groups: group A (D-galactose group, n=10), group B (D-galactose+α-lipoic acid group, n=10), group C (α-lipoic acid group, n=10), and group D (control group, n=10). Auditory brainstem response (ABR) was used to detect the hearing threshold. Colorimetry was used to analyze activity of superoxide dismutase (SOD) and...

  12. The Role of Mitochondrial DNA in Mediating Alveolar Epithelial Cell Apoptosis and Pulmonary Fibrosis

    Directory of Open Access Journals (Sweden)

    Seok-Jo Kim

    2015-09-01

    Full Text Available Convincing evidence has emerged demonstrating that impairment of mitochondrial function is critically important in regulating alveolar epithelial cell (AEC programmed cell death (apoptosis that may contribute to aging-related lung diseases, such as idiopathic pulmonary fibrosis (IPF and asbestosis (pulmonary fibrosis following asbestos exposure. The mammalian mitochondrial DNA (mtDNA encodes for 13 proteins, including several essential for oxidative phosphorylation. We review the evidence implicating that oxidative stress-induced mtDNA damage promotes AEC apoptosis and pulmonary fibrosis. We focus on the emerging role for AEC mtDNA damage repair by 8-oxoguanine DNA glycosylase (OGG1 and mitochondrial aconitase (ACO-2 in maintaining mtDNA integrity which is important in preventing AEC apoptosis and asbestos-induced pulmonary fibrosis in a murine model. We then review recent studies linking the sirtuin (SIRT family members, especially SIRT3, to mitochondrial integrity and mtDNA damage repair and aging. We present a conceptual model of how SIRTs modulate reactive oxygen species (ROS-driven mitochondrial metabolism that may be important for their tumor suppressor function. The emerging insights into the pathobiology underlying AEC mtDNA damage and apoptosis is suggesting novel therapeutic targets that may prove useful for the management of age-related diseases, including pulmonary fibrosis and lung cancer.

  13. Polydatin Protecting Kidneys against Hemorrhagic Shock-Induced Mitochondrial Dysfunction via SIRT1 Activation and p53 Deacetylation

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    Zhenhua Zeng

    2016-01-01

    Full Text Available Objectives. To ascertain if mitochondrial dysfunction (MD of kidney cells is present in severe hemorrhagic shock and to investigate whether polydatin (PD can attenuate MD and its protective mechanisms. Research Design and Methods. Renal tubular epithelial cells (RTECs from rat kidneys experiencing HS and a cell line (HK-2 under hypoxia/reoxygenation (H/R treatment were used. Morphology and function of mitochondria in isolated RTECs or cultured HK-2 cells were evaluated, accompanied by mitochondrial apoptosis pathway-related proteins. Result. Severe MD was found in rat kidneys, especially in RTECs, as evidenced by swollen mitochondria and poorly defined cristae, decreased mitochondrial membrane potential (ΔΨm, and reduced ATP content. PD treatment attenuated MD partially and inhibited expression of proapoptotic proteins. PD treatment increased SIRT1 activity and decreased acetylated-p53 levels. Beneficial effect of PD was abolished partially when the SIRT1 inhibitor Ex527 was added. Similar phenomena were shown in the H/R cell model; when pifithrin-α (p53 inhibitor was added to the PD/Ex527 group, considerable therapeutic effects were regained compared with the PD group apart from increased SIRT1 activity. Conclusions. MD is present in severe HS, and PD can attenuate MD of RTECs via the SIRT1-p53 pathway. PD might be a promising therapeutic drug for acute renal injury.

  14. Inhibition of mitochondrial calcium uniporter protects neurocytes from ischemia/reperfusion injury via the inhibition of excessive mitophagy.

    Science.gov (United States)

    Yu, Shoushui; Zheng, Shengfa; Leng, Jing; Wang, Shilei; Zhao, Tao; Liu, Jia

    2016-08-15

    Mitophagy plays an important role in mitochondrial quality control and cell survival during the process of ischemia/reperfusion (I/R) injury. Mitochondrial calcium uniporter (MCU) is the most important channel responsible for Ca(2+) influx into mitochondria and Ca(2+) signal plays a potential role in modulating mitophagy. However, the effect of MCU on mitophagy during the process of I/R injury remains unknown. This study constructed an in vitro I/R model by subjecting oxygen and glucose deprivation/reperfusion (OGD/RP) model to SH-SY5Y cells to mimic the cerebral I/R injury and aimed to explore the exact effect of MCU on I/R induced mitophagy. The results showed that OGD/RP induced autophagy and mitophagy in SH-SY5Y cells. Ru360, the inhibitor of MCU, improved mitochondrial morphology and fuctional stability as well as cell viability, significantly reduced OGD/RP induced mitophagy as evidenced by the decrease in Beclin-1 and the increase in Tom20 and P62 expression. Whereas spermine, the agonist of MCU, had no significant impact on the expression of those mitophagy related proteins compared with OGD/RP group. This study indicates that inhibition of MCU can inhibit excessive mitophagy and protect the neurocytes from I/R injury.

  15. Experimental data suggesting that inflammation mediated rat liver mitochondrial dysfunction results from secondary hypoxia rather than from direct effects of inflammatory mediators

    Directory of Open Access Journals (Sweden)

    Adelheid eWeidinger

    2013-06-01

    Full Text Available Systemic inflammatory response (SIR comprises direct effects of inflammatory mediators (IM and indirect effects, such as secondary circulatory failure which results in tissue hypoxia (HOX. These two key components, SIR and HOX, cause multiple organ failure (MOF. Since HOX and IM occur and interact simultaneously in vivo, it is difficult to clarify their individual pathological impact. To eliminate this interaction, precision cut liver slices (PCLS were used in this study aiming to dissect the effects of HOX and IM on mitochondrial function, integrity of cellular membrane and the expression of genes associated with inflammation. HOX was induced by incubating PCLS or rat liver mitochondria at pO2<1% followed by reoxygenation (HOX/ROX model. Inflammatory injury was stimulated by incubating PCLS with IM (IM model. We found upregulation of inducible nitric oxide synthase (iNOS expression only in the IM model, while heme oxygenase 1 (HO-1 expression was upregulated only in the HOX/ROX model. Elevated expression of interleukin 6 (IL-6 was found in both models reflecting converging pathways regulating the expression of this gene. Both models caused damage to hepatocytes resulting in the release of alanine aminotransferase (ALT. The leakage of aspartate aminotransferase (AST was observed only during the hypoxic phase in the HOX/ROX model. The reoxygenation phase of HOX, but not IM, drastically impaired mitochondrial electron supply via complex I and II. Additional experiments performed with isolated mitochondria showed that free iron, released during HOX, is likely a key prerequisite of mitochondrial dysfunction induced during the reoxygenation phase. Our data suggests that mitochondrial dysfunction, previously observed in in vivo SIR-models is the result of secondary circulatory failure inducing HOX rather than the result of a direct interaction of IM with liver cells.

  16. Exercise mediated protection of diabetic heart through modulation of microRNA mediated molecular pathways.

    Science.gov (United States)

    Lew, Jason Kar Sheng; Pearson, James T; Schwenke, Daryl O; Katare, Rajesh

    2017-01-13

    Hyperglycaemia, hypertension, dyslipidemia and insulin resistance collectively impact on the myocardium of people with diabetes, triggering molecular, structural and myocardial abnormalities. These have been suggested to aggravate oxidative stress, systemic inflammation, myocardial lipotoxicity and impaired myocardial substrate utilization. As a consequence, this leads to the development of a spectrum of cardiovascular diseases, which may include but not limited to coronary endothelial dysfunction, and left ventricular remodelling and dysfunction. Diabetic heart disease (DHD) is the term used to describe the presence of heart disease specifically in diabetic patients. Despite significant advances in medical research and long clinical history of anti-diabetic medications, the risk of heart failure in people with diabetes never declines. Interestingly, sustainable and long-term exercise regimen has emerged as an effective synergistic therapy to combat the cardiovascular complications in people with diabetes, although the precise molecular mechanism(s) underlying this protection remain unclear. This review provides an overview of the underlying mechanisms of hyperglycaemia- and insulin resistance-mediated DHD with a detailed discussion on the role of different intensities of exercise in mitigating these molecular alterations in diabetic heart. In particular, we provide the possible role of exercise on microRNAs, the key molecular regulators of several pathophysiological processes.

  17. Cardioprotection by combination of three compounds from ShengMai preparations in mice with myocardial ischemia/reperfusion injury through AMPK activation-mediated mitochondrial fission

    Science.gov (United States)

    Li, Fang; Fan, Xiaoxue; Zhang, Yu; Pang, Lizhi; Ma, Xiaonan; Song, Meijia; Kou, Junping; Yu, Boyang

    2016-01-01

    GRS is a drug combination of three active components including ginsenoside Rb1, ruscogenin and schisandrin. It derived from the well-known TCM formula ShengMai preparations, a widely used traditional Chinese medicine for the treatment of cardiovascular diseases in clinic. The present study explores the cardioprotective effects of GRS on myocardial ischemia/reperfusion (MI/R) injury compared with ShengMai preparations and investigates the underlying mechanisms. GRS treatment significantly attenuated MI/R injury and exhibited similar efficacy as Shengmai preparations, as evidenced by decreased myocardium infarct size, ameliorated histological features, the decrease of LDH production and improved cardiac function, and also produced a significant decrease of apoptotic index. Mechanistically, GRS alleviated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway as reflected by inhibition of caspase-3 activity, normalization of Bcl-2/Bax levels and improved mitochondrial function. Moreover, GRS prevented cardiomyocytes mitochondrial fission and upregulated AMPKα phosphorylation. Interestingly, AMPK activation prevented hypoxia and reoxygenation induced mitochondrial fission in cardiomyocytes and GRS actions were significantly attenuated by knockdown of AMPKα. Collectively, these data show that GRS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and modulating AMPK activation-mediated mitochondrial fission, thereby providing a rationale for future clinical applications and potential therapeutic strategy for MI/R injury. PMID:27869201

  18. 7-O-Geranylquercetin induces apoptosis in gastric cancer cells via ROS-MAPK mediated mitochondrial signaling pathway activation.

    Science.gov (United States)

    Zhu, Yanyan; Jiang, Yameng; Shi, Lei; Du, Linying; Xu, Xiaodong; Wang, Enxia; Sun, Yong; Guo, Xin; Zou, Boyang; Wang, Huaxin; Wang, Changyuan; Sun, Lidan; Zhen, Yuhong

    2017-03-01

    7-O-Geranylquercetin (GQ) is a novel O-alkylated derivate of quercetin. In this study, we evaluated its apoptosis induction effects in human gastric cancer cell lines SGC-7901 and MGC-803 and explored the potential molecular mechanisms. The results demonstrated that GQ lowered viability of SGC-7901 and MGC-803 cells in a dose- and time-dependent manner without apparent cytotoxicity to human gastric epithelial cell line GES-1. GQ could induce apoptosis in SGC-7901 and MGC-803cells, and arrest the gastric cancer cells at G2/M phase. Mechanism study showed that GQ triggered generation of reactive oxygen species (ROS), then activated p38 and JNK signaling pathways, subsequently led to mitochondrial impairment by regulating the expression of Bcl-2, Bcl-xl and Bax, and finally promoted the release of cytochrome c and the activation of caspases to induce apoptosis. In addition, Z-VAD-FMK (caspase inhibitor) could reverse GQ-induced apoptosis. SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) could rescue GQ-induced cell death and attenuate mitochondrial signal pathway activation. Furthermore, NAC (ROS inhibitor) could rescue GQ-induced cell death, reduce ROS generation, decrease the phosphorylation of p38 and JNK, and then attenuate the activation of mitochondrial signal pathway. Taken together, GQ induces caspase-dependent apoptosis in gastric cancer cells through activating ROS-MAPK mediated mitochondrial signal pathway. This study highlights the potential use of GQ as a gastric cancer therapeutic agent. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Apigenin drives the production of reactive oxygen species and initiates a mitochondrial mediated cell death pathway in prostate epithelial cells.

    Science.gov (United States)

    Morrissey, Colm; O'Neill, Amanda; Spengler, Barbara; Christoffel, Volker; Fitzpatrick, John M; Watson, R William G

    2005-05-01

    Phytoestrogens may reduce tumorigenesis in prostate cancer. We screened five phytoestrogens for their effect on cell growth and apoptosis in PWR-1E, LNCaP, PC-3, and DU145 prostate epithelial cells in vitro. We assessed cell number, proliferation, and apoptosis using crystal violet assays, flow cytometric analysis, and TUNEL. Focusing specifically on apigenin we assessed the ability of calpain, serine protease, caspase, estrogen receptor, and ceramide synthase inhibitors to block apigenin induced apoptosis. We also analyzed caspase 3, 7, 8, 9, Bcl-2, Bax, Bid, and cytochrome C by Western analysis, and mitochondrial permeability and reactive oxygen species production by flow cytometry using mitosensor(TM) and DCFH-DA, respectively. Apigenin and silybinin significantly reduced cell number, with apigenin inducing apoptosis in PWR-1E, LNCaP, PC-3, and DU145 cells. The PC-3 and DU145 cells were less susceptible to apigenin induced apoptosis then LNCaP and PWR-1E cells. The induction of apoptosis by apigenin was caspase dependent. Apigenin generated reactive oxygen species, a loss of mitochondrial Bcl-2 expression, mitochondrial permeability, cytochrome C release, and the cleavage of caspase 3, 7, 8, and 9 and the concomitant cleavage of the inhibitor of apoptosis protein, cIAP-2. The overexpression of Bcl-2 in LNCaP B10 cells reduced the apoptotic effects of apigenin. Apigenin induces cell death in prostate epithelial cells using a mitochondrial mediated cell death pathway. Bcl-2 has a role in inhibiting apigenin induced cell death in prostate epithelial cells. (c) 2004 Wiley-Liss, Inc.

  20. B4G2 Induces Mitochondrial Apoptosis by the ROS-Mediated Opening of Ca2+-Dependent Permeability Transition Pores

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    Nan Yao

    2015-09-01

    Full Text Available Background/Aims: Hepatocellular carcinoma (HCC is the most common type of liver cancer. At present, only sorafenib is approved to treat HCC. In this study, we found that a 23-hydroxybetulinic acid derivative, B4G2, exhibited potent antiproliferative activity in HCC cell lines. Methods: We used four HCC cell lines (HepG2, HepG2/ADM, Hep3B and Bel-7402 to evaluate the anti-tumour activity and explore underlying mechanisms by which B4G2 induces apoptosis. Results: Among these cell lines, HepG2 showed the highest sensitivity to B4G2. HepG2 cells treated with B4G2 showed a depolarized mitochondrial membrane potential, released cytochrome c, activated caspase-9 and caspase-3 and cleaved poly ADP-ribose polymerase (PARP. However, Z-VAD-FMK, a pan-caspase inhibitor, did not attenuate B4G2-induced apoptosis, implying that the induction of mitochondrial apoptosis by B4G2 may be independent of caspases. Moreover, pre-treatment with MgCl2, a blocker of Ca2+-dependent permeability transition (PT pores, attenuated the depolarization of the mitochondrial potential and decreased the population of apoptotic cells, indicating that B4G2-induced apoptosis was partly dependent on the opening of the Ca2+-dependent PT pores. B4G2 also increased the levels of intracellular calcium and reactive oxygen species (ROS. Furthermore, an ROS scavenger, N-acetyl-cysteine (NAC, markedly decreased the accumulation of intracellular calcium and apoptosis. Conclusion: This is the first demonstration that B4G2 inhibits the growth of HCC cells and induces mitochondrial apoptosis in hepatocellular carcinoma cells by the ROS-mediated opening of Ca2+-dependent permeability transition pores.

  1. Pioglitazone Improves Mitochondrial Function in the Remnant Kidney and Protects against Renal Fibrosis in 5/6 Nephrectomized Rats

    Directory of Open Access Journals (Sweden)

    Li Sun

    2017-08-01

    Full Text Available Pioglitazone is a type of peroxisome proliferator-activated receptor γ (PPARγ agonist and has been demonstrated to be effective in chronic kidney diseases (CKD treatment. However, the underlying mechanism involved in the renoprotection of pioglitazone has not been fully revealed. In the present study, the renoprotective mechanism of pioglitazone was investigated in 5/6 nephrectomized (Nx rats and TGF-β1-exposed HK-2 cells. Pioglitazone attenuated renal injury and improved renal function, as examined by 24 h urinary protein, blood urea nitrogen and plasma creatinine in Nx rats. Renal fibrosis and enhanced expressions of profibrotic proteins TGF-β1, fibronectin and collagen I caused by Nx were significantly alleviated by pioglitazone. In addition, pioglitazone protected mitochondrial functions by stabilizing the mitochondrial membrane potential, inhibiting ROS generation, maintaining ATP production and the activities of complexes I and III, and preventing cytochrome C leakage from mitochondria. Pioglitazone also upregulated the expression levels of ATP synthase β, COX I and NDUFB8, which were downregulated in the kidney of Nx rats and TGF-β1-exposed HK-2 cells. Furthermore, pioglitazone increased fusion proteins Opa-1 and Mfn2 expressions and decreased fission protein Drp1 expression. The results imply that pioglitazone may exert the renoprotective effects through modulating mitochondrial electron transport chain and mitochondrial dynamics in CKD. Finally, these recoveries were completely or partly inhibited by GW9662, which suggests that these effects at least partly PPARγ dependent. This study provides evidence for the pharmacological mechanism of pioglitazone in the treatment of CKD.

  2. Cholesterol secoaldehyde induces apoptosis in J774 macrophages via mitochondrial pathway but not involving reactive oxygen species as mediators.

    Science.gov (United States)

    Gao, Xueli; Raghavamenon, Achuthan C; D'Auvergne, Oswald; Uppu, Rao M

    2009-11-13

    Cholesterol secoaldehyde (3beta-hydroxy-5-oxo-5,6-secocholestan-6-al or ChSeco) is an oxysterol known to be formed in reactions of ozone with cholesterol and also when cholesterol-5alpha-hydroperoxide undergoes Hock cleavage. In view of its widespread occurrence and atherogenic potential, we examined the effects of ChSeco on mouse J774 macrophage viability and events associated with apoptosis. A dose-dependent decrease in cell viability, disruptions in mitochondrial transmembrane potential (64+/-5.5%; mean+/-SD, n=3), increased levels of cytosolic cytochrome c (8.8+/-0.84 ng/ml; mean+/-SD, n=3), activation of caspase-3 (ca. 3.6-fold) and caspase-9 (ca.1.8-fold), and increased DNA fragmentation (ca. 5-fold), all indicative of apoptosis, were observed in response to exposure to ChSeco. The apoptotic nature of cell death in macrophages was confirmed by dual staining with acridine orange and ethidium bromide. However, unlike the case with cardiomyoblasts and neuronal cells, the apoptotic process in these immune cells was not mediated by increased levels of reactive oxygen species as indicated by a minimal or no increase in 2',7'-dichlorofluorescein fluorescence. It is suggested that the apoptotic process is mediated via the mitochondrial pathway and that ChSeco formed in biological environments contributes to the initiation, progression, and culmination of atherosclerotic plaque formation, as these processes are critically dependent on macrophage apoptosis.

  3. Protective effects of crude garlic by reducing iron-mediated oxidative stress, proliferation and autophagy in rats.

    Science.gov (United States)

    Nahdi, Afef; Hammami, Imen; Kouidhi, Wided; Chargui, Abderrahman; Ben Ammar, Awatef; Hamdaoui, Mohamed Hédi; El May, Ahmed; El May, Michèle

    2010-10-01

    The impact of garlic, known for its antioxidant activities, on iron metabolism has been poorly investigated. The aim of this work was to study the effect of crude garlic pre-treatment on iron-mediated lipid peroxidation, proliferation and autophagy for 5 weeks. Rats were fed distilled water or garlic solution (1 g/kg body weight) by gavage for the first 3 weeks as pre-treatment and received a basal diet supplemented or not with ferrous sulfate (650 mg Fe/kg diet) for the last 2 weeks of treatment. Immunohistochemistry labeling and ultrastuctural observations were used to evaluate the iron deleterious effects in the liver. Iron supplementation induced cell proliferation predominantly in non parenchymal cells comparing to hepatocytes, but not apoptosis. In addition, iron was accumulated within the hepatic lysosomes where it triggers autophagy as evidenced by the formation of autophagic vesicles detected by LC3-II staining. It also induced morphologic alterations of the mitochondrial membranes due to increased lipid peroxidation as shown by elevated iron and malondialdehyde concentrations in serum and tissues. Garlic pre-treatment reduced iron-catalyzed lipid peroxidation by decreasing the malondialdehyde level in the liver and colon and by enhancing the status of antioxidants. In addition, garlic reduced the iron-mediated cell proliferation and autophagy by lowering iron storage in the liver and protected mitochondrial membrane. Based on these results, garlic treatment significantly prevented iron-induced oxidative stress, proliferation and autophagy at both biochemical and histological levels due to its potent free radical scavenging and antioxidant properties.

  4. Mitochondrial-Targeted Catalase Protects Against High-Fat Diet-Induced Muscle Insulin Resistance by Decreasing Intramuscular Lipid Accumulation.

    Science.gov (United States)

    Lee, Hui-Young; Lee, Jae Sung; Alves, Tiago; Ladiges, Warren; Rabinovitch, Peter S; Jurczak, Michael J; Choi, Cheol Soo; Shulman, Gerald I; Samuel, Varman T

    2017-08-01

    We explored the role of reactive oxygen species (ROS) in the pathogenesis of muscle insulin resistance. We assessed insulin action in vivo with a hyperinsulinemic-euglycemic clamp in mice expressing a mitochondrial-targeted catalase (MCAT) that were fed regular chow (RC) or a high-fat diet (HFD) or underwent an acute infusion of a lipid emulsion. RC-fed MCAT mice were similar to littermate wild-type (WT) mice. However, HFD-fed MCAT mice were protected from diet-induced insulin resistance. In contrast, an acute lipid infusion caused muscle insulin resistance in both MCAT and WT mice. ROS production was decreased in both HFD-fed and lipid-infused MCAT mice and cannot explain the divergent response in insulin action. MCAT mice had subtly increased energy expenditure and muscle fat oxidation with decreased intramuscular diacylglycerol (DAG) accumulation, protein kinase C-θ (PKCθ) activation, and impaired insulin signaling with HFD. In contrast, the insulin resistance with the acute lipid infusion was associated with increased muscle DAG content in both WT and MCAT mice. These studies suggest that altering muscle mitochondrial ROS production does not directly alter the development of lipid-induced insulin resistance. However, the altered energy balance in HFD-fed MCAT mice protected them from DAG accumulation, PKCθ activation, and impaired muscle insulin signaling. © 2017 by the American Diabetes Association.

  5. Honokiol induces reactive oxygen species-mediated apoptosis in Candida albicans through mitochondrial dysfunction

    Science.gov (United States)

    Sun, Lingmei; Liao, Kai; Hang, Chengcheng; Wang, Dayong

    2017-01-01

    Objective To investigate the effects of honokiol on induction of reactive oxygen species (ROS), antioxidant defense systems, mitochondrial dysfunction, and apoptosis in Candida albicans. Methods To measure ROS accumulation, 2′,7′-dichlorofluorescein diacetate fluorescence was used. Lipid peroxidation was assessed using both fluorescence staining and a thiobarbituric acid reactive substances (TBARS) assay. Protein oxidation was determined using dinitrophenylhydrazine derivatization. Antioxidant enzymatic activities were measured using commercially available detection kits. Superoxide dismutase (SOD) genes expression was measured using real time RT-PCR. To assess its antifungal abilities and effectiveness on ROS accumulation, honokiol and the SOD inhibitor N,N′-diethyldithiocarbamate (DDC) were used simultaneously. Mitochondrial dysfunction was assessed by measuring the mitochondrial membrane potential (mtΔψ). Honokiol-induced apoptosis was assessed using an Annexin V-FITC apoptosis detection kit. Results ROS, lipid peroxidation, and protein oxidation occurred in a dose-dependent manner in C. albicans after honokiol treatment. Honokiol caused an increase in antioxidant enzymatic activity. In addition, honokiol treatment induced SOD genes expression in C. albicans cells. Moreover, addition of DDC resulted in increased endogenous ROS levels and potentiated the antifungal activity of honokiol. Mitochondrial dysfunction was confirmed by measured changes to mtΔψ. The level of apoptosis increased in a dose-dependent manner after honokiol treatment. Conclusions Collectively, these results indicate that honokiol acts as a pro-oxidant in C. albicans. Furthermore, the SOD inhibitor DDC can be used to potentiate the activity of honokiol against C. albicans. PMID:28192489

  6. AS-2, a novel inhibitor of p53-dependent apoptosis, prevents apoptotic mitochondrial dysfunction in a transcription-independent manner and protects mice from a lethal dose of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Akinori, E-mail: morita@tokushima-u.ac.jp [Department of Radiological Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Ariyasu, Shinya [Center for Technologies against Cancer, Tokyo University of Science, Chiba 278-8510 (Japan); Wang, Bing [Radiation Risk Reduction Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Asanuma, Tetsuo; Onoda, Takayoshi [Department of Radiological Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Sawa, Akiko [Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510 (Japan); Tanaka, Kaoru [Radiation Risk Reduction Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Takahashi, Ippei [Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Togami, Shotaro [Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510 (Japan); Nenoi, Mitsuru [Radiation Risk Reduction Research Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Inaba, Toshiya [Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Aoki, Shin [Center for Technologies against Cancer, Tokyo University of Science, Chiba 278-8510 (Japan); Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510 (Japan)

    2014-08-08

    Highlights: • A bidentate HQ derivative, AS-2, suppresses p53-dependent apoptosis by DNA damage. • AS-2 does not significantly affect nuclear p53 response. • UV-excited blue emission of AS-2 clearly showed its extranuclear localization. • AS-2 prevents mitochondrial dysfunction despite the increase of mitochondrial p53. • AS-2 protects mice from a radiation dose that causes lethal hematopoietic syndrome. - Abstract: In a previous study, we reported that some tetradentate zinc(II) chelators inhibit p53 through the denaturation of its zinc-requiring structure but a chelator, Bispicen, a potent inhibitor of in vitro apoptosis, failed to show any efficient radioprotective effect against irradiated mice because the toxicity of the chelator to mice. The unsuitability of using tetradentate chelators as radioprotectors prompted us to undertake a more extensive search for p53-inhibiting agents that are weaker zinc(II) chelators and therefore less toxic. Here, we show that an 8-hydroxyquinoline (8HQ) derivative, AS-2, suppresses p53-dependent apoptosis through a transcription-independent mechanism. A mechanistic study using cells with different p53 characteristics revealed that the suppressive effect of AS-2 on apoptosis is specifically mediated through p53. In addition, AS-2 was less effective in preventing p53-mediated transcription-dependent events than pifithrin-μ (PFTμ), an inhibitor of transcription-independent apoptosis by p53. Fluorescence visualization of the extranuclear distribution of AS-2 also supports that it is ineffective on the transcription-dependent pathway. Further investigations revealed that AS-2 suppressed mitochondrial apoptotic events, such as the mitochondrial release of intermembrane proteins and the loss of mitochondrial membrane potential, although AS-2 resulted in an increase in the mitochondrial translocation of p53 as opposed to the decrease of cytosolic p53, and did not affect the apoptotic interaction of p53 with Bcl-2. AS-2 also

  7. Citicoline (CDP-choline) protects myocardium from ischemia/reperfusion injury via inhibiting mitochondrial permeability transition.

    Science.gov (United States)

    Hernández-Esquivel, Luz; Pavón, Natalia; Buelna-Chontal, Mabel; González-Pacheco, Héctor; Belmont, Javier; Chávez, Edmundo

    2014-02-06

    Oxidative stress emerges after reperfusion of an organ following an ischemic period and results in tissue damage. In the heart, an amplified generation of reactive oxygen species and a significant Ca(2+) accumulation cause ventricular arrhythmias and mitochondrial dysfunction. This occurs in consequence of increased non-specific permeability. A number of works have shown that permeability transition is a common substrate that underlies the reperfusion-induced heart injury. The aim of this work was to explore the possibility that CDP-choline may circumvent heart damage and mitochondrial permeability transition. Rats were injected i.p. with CDP-choline at 20 mg/kg body weight. Heart electric behavior was followed during a closure/opening cycle of the left coronary descendent artery. Heart mitochondria were isolated from rats treated with CDP-choline, and their function was evaluated by analyzing Ca(2+) movements, achievement of a high level of the transmembrane potential, and respiratory control. Oxidative stress was estimated following the activity of the enzymes cis-aconitase and superoxide dismutase, as well as the disruption of mitochondrial DNA. This study shows that CDP-choline avoided ventricular arrhythmias and drop of blood pressure. Results also show that mitochondria, isolated from CDP-choline-treated rats, maintained selective permeability, retained accumulated Ca(2+), an elevated value of transmembrane potential, and a high ratio of respiratory control. Furthermore, activity of cis-aconitase enzyme and mDNA structure were preserved. This work introduces CDP-choline as a useful tool to preserve heart function from reperfusion damage by inhibiting mitochondrial permeability transition. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Negundoside, an irridiod glycoside from leaves of Vitex negundo, protects human liver cells against calcium-mediated toxicity induced by carbon tetrachloride

    Institute of Scientific and Technical Information of China (English)

    Sheikh A Tasduq; Peerzada J Kaiser; Bishan D Gupta; Vijay K Gupta; Rakesh K Johri

    2008-01-01

    AIM: To evaluate the protective effect of 2'-p-hydroxy benzoylmussaenosidic acid [negundoside (NG), against carbon tetrachloride (CCl4)-induced toxicity in HUH-7 cells.METHODS: CCl4 is a well characterized hepatotoxin, and inducer of cytochrome P4502E1 (CYP2E1)-mediated oxidative stress. In addition, lipid peroxidation and accumulation of intracellular calcium are important steps in the pathway involved in CCl4 toxicity. Liver cells (HUH-7) were treated with CCl4, and the mechanism of the cytoprotective effect of NG was assessed. Silymarin, a known hepatoprotective drug, was used as control.RESULTS: NG protected HUH-7 cells against CCl4 toxicity and loss of viability without modulating CYP2E1 activity. Prevention of CCl4, toxicity was associated with a reduction in oxidative damage as reflected by decreased generation of reactive oxygen species (ROS), a decrease in lipid peroxidation and accumulation of intracellular Ca2+ levels and maintenance of intracellular glutathione homeostasis. Decreased mitochondrial membrane potential (MMP), induction of caspases mediated DNA fragmentation and cell cycle arrest, as a result of CCl4 treatment, were also blocked by NG. The protection afforded by NG seemed to be mediated by activation of cyclic adenosine monophosphate (cAMP) synthesis and inhibition of phospholipases (cPLA2).CONCLUSION: NG exerts a protective effect on CYP2El-dependent CCl4 toxicity via inhibition of lipid peroxidation, followed by an improved intracellular calcium homeostasis and inhibition of Ca2+-dependent proteases.

  9. SLC25A23 augments mitochondrial Ca²⁺ uptake, interacts with MCU, and induces oxidative stress-mediated cell death.

    Science.gov (United States)

    Hoffman, Nicholas E; Chandramoorthy, Harish C; Shanmughapriya, Santhanam; Zhang, Xueqian Q; Vallem, Sandhya; Doonan, Patrick J; Malliankaraman, Karthik; Guo, Shuchi; Rajan, Sudarsan; Elrod, John W; Koch, Walter J; Cheung, Joseph Y; Madesh, Muniswamy

    2014-03-01

    Emerging findings suggest that two lineages of mitochondrial Ca(2+) uptake participate during active and resting states: 1) the major eukaryotic membrane potential-dependent mitochondrial Ca(2+) uniporter and 2) the evolutionarily conserved exchangers and solute carriers, which are also involved in ion transport. Although the influx of Ca(2+) across the inner mitochondrial membrane maintains metabolic functions and cell death signal transduction, the mechanisms that regulate mitochondrial Ca(2+) accumulation are unclear. Solute carriers--solute carrier 25A23 (SLC25A23), SLC25A24, and SLC25A25--represent a family of EF-hand-containing mitochondrial proteins that transport Mg-ATP/Pi across the inner membrane. RNA interference-mediated knockdown of SLC25A23 but not SLC25A24 and SLC25A25 decreases mitochondrial Ca(2+) uptake and reduces cytosolic Ca(2+) clearance after histamine stimulation. Ectopic expression of SLC25A23 EF-hand-domain mutants exhibits a dominant-negative phenotype of reduced mitochondrial Ca(2+) uptake. In addition, SLC25A23 interacts with mitochondrial Ca(2+) uniporter (MCU; CCDC109A) and MICU1 (CBARA1) while also increasing IMCU. In addition, SLC25A23 knockdown lowers basal mROS accumulation, attenuates oxidant-induced ATP decline, and reduces cell death. Further, reconstitution with short hairpin RNA-insensitive SLC25A23 cDNA restores mitochondrial Ca(2+) uptake and superoxide production. These findings indicate that SLC25A23 plays an important role in mitochondrial matrix Ca(2+) influx.

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

    Science.gov (United States)

    Ruiz, A; Alberdi, E; Matute, C

    2014-04-10

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

  11. Heat stress induces apoptosis through a Ca²⁺-mediated mitochondrial apoptotic pathway in human umbilical vein endothelial cells.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Heat stress can be acutely cytotoxic, and heat stress-induced apoptosis is a prominent pathological feature of heat-related illnesses, although the precise mechanisms by which heat stress triggers apoptosis are poorly defined.The percentages of viability and cell death were assessed by WST-1 and LDH release assays. Apoptosis was assayed by DNA fragmentation and caspase activity. Expression of cleaved PARP, Apaf-1, phospho-PERK, Phospho-eIF2a, ATF4, XBP-1s, ATF6, GRP78, phospho-IP3R, RYR and SERCA was estimated by Western blot. The effect of calcium overload was determined using flow cytometric analysis with the fluorescent probe Fluo-3/AM. The generation of ROS (O2-, H2O2, NO was labeled by confocal laser scanning microscopy images of fluorescently and flow cytometry.In this study, we found that heat stress in HUVEC cells activated initiators of three major unfolded protein response (UPR signaling transduction pathways: PERK-eIF2a-ATF4, IRE1-XBP-1S and ATF6 to protect against ER stress, although activation declined over time following cessation of heat stress. Furthermore, we show that intense heat stress may induce apoptosis in HUVEC cells through the calcium-mediated mitochondrial apoptotic pathway, as indicated by elevation of cytoplasmic Ca2+, expression of Apaf-1, activation of caspase-9 and caspase-3, PARP cleavage, and ultimately nucleosomal DNA fragmentation; Reactive oxygen species (ROS appear to act upstream in this process. In addition, we provide evidence that IP3R upregulation may promote influx of Ca2+ into the cytoplasm after heat stress.Our findings describe a novel mechanism for heat stress-induced apoptosis in HUVEC cells: following elevation of cytoplasm Ca2+, activation of the mitochondrial apoptotic pathway via the IP3R upregulation, with ROS acting as an upstream regulator of the process.

  12. Pleiotropic regulation of mitochondrial function by adipose triglyceride lipase-mediated lipolysis.

    Science.gov (United States)

    Kratky, Dagmar; Obrowsky, Sascha; Kolb, Dagmar; Radovic, Branislav

    2014-01-01

    Lipolysis is defined as the catabolism of triacylglycerols (TGs) stored in cellular lipid droplets. Recent discoveries of essential lipolytic enzymes and characterization of numerous regulatory proteins and mechanisms have fundamentally changed our perception of lipolysis and its impact on cellular metabolism. Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme for TG catabolism in most cells and tissues. This review focuses on recent advances in understanding the (patho)physiological impact due to defective lipolysis by ATGL deficiency on mitochondrial (dys)function. Depending on the type of cells and tissues investigated, absence of ATGL has pleiotropic roles in mitochondrial function. Copyright © 2013 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  13. NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway.

    Directory of Open Access Journals (Sweden)

    Yaodong Dong

    Full Text Available Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1 cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss.

  14. NaHS Protects Cochlear Hair Cells from Gentamicin-Induced Ototoxicity by Inhibiting the Mitochondrial Apoptosis Pathway

    Science.gov (United States)

    Dong, Yaodong; Liu, Dongliang; Hu, Yue; Ma, Xiulan

    2015-01-01

    Aminoglycoside antibiotics such as gentamicin could cause ototoxicity in mammalians, by inducing oxidative stress and apoptosis in sensory hair cells of the cochlea. Sodium hydrosulfide (NaHS) is reported to alleviate oxidative stress and apoptosis, but its role in protecting aminoglycoside-induced hearing loss is unclear. In this study, we investigated the anti-oxidant and anti-apoptosis effect of NaHS in in vitro cultured House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and isolated mouse cochlea. Results from cultured HEI-OC1 cells and cochlea consistently indicated that NaHS exhibited protective effects from gentamicin-induced ototoxicity, evident by maintained cell viability, hair cell number and cochlear morphology, reduced reactive oxygen species production and mitochondrial depolarization, as well as apoptosis activation of the intrinsic pathway. Moreover, in the isolated cochlear culture, NaHS was also demonstrated to protect the explant from gentamicin-induced mechanotransduction loss. Our study using multiple in vitro models revealed for the first time, the potential of NaHS as a therapeutic agent in protecting against aminoglycoside-induced hearing loss. PMID:26295804

  15. Mitochondrial Respiratory Chain Inhibitors Involved in ROS Production Induced by Acute High Concentrations of Iodide and the Effects of SOD as a Protective Factor

    Directory of Open Access Journals (Sweden)

    Lingyan Wang

    2015-01-01

    Full Text Available A major source of reactive oxygen species (ROS generation is the mitochondria. By using flow cytometry of the mitochondrial fluorescent probe, MitoSOX Red, western blot of mitochondrial ROS scavenger Peroxiredoxin (Prx 3 and fluorescence immunostaining, ELISA of cleaved caspases 3 and 9, and TUNEL staining, we demonstrated that exposure to 100 μM KI for 2 hours significantly increased mitochondrial superoxide production and Prx 3 protein expression with increased expressions of cleaved caspases 3 and 9. Besides, we indicated that superoxide dismutase (SOD at 1000 unit/mL attenuated the increase in mitochondrial superoxide production, Prx 3 protein expression, and lactate dehydrogenase (LDH release and improved the relative cell viability at 100 μM KI exposure. However, SOD inhibitor diethyldithiocarbamic acid (DETC (2 mM, Rotenone (0.5 μM, a mitochondrial complex I inhibitor, and Antimycin A (10 μM, a complex III inhibitor, caused an increase in mitochondrial superoxide production, Prx 3 protein expression, and LDH release and decreased the relative cell viability. We conclude that the inhibitors of mitochondrial respiratory chain complex I or III may be involved in oxidative stress caused by elevated concentrations of iodide, and SOD demonstrates its protective effect on the Fischer rat thyroid cell line (FRTL cells.

  16. Momordin Ic induces HepG2 cell apoptosis through MAPK and PI3K/Akt-mediated mitochondrial pathways.

    Science.gov (United States)

    Wang, Jing; Yuan, Li; Xiao, Haifang; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo

    2013-06-01

    Momordin Ic is a natural triterpenoid saponin enriched in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. So far, there is little scientific evidence for momordin Ic with regard to the anti-tumor activities. The aim of this work was to elucidate the anti-tumor effect of momordin Ic and the signal transduction pathways involved. We found that momordin Ic induced apoptosis in human hepatocellular carcinoma HepG2 cells, which were supported by DNA fragmentation, caspase-3 activation and PARP cleavage. Meanwhile, momordin Ic triggered reactive oxygen species (ROS) production together with collapse of mitochondrial membrane potential, cytochrome c release, down-regulation of Bcl-2 and up-regulation of Bax expression. The activation of p38 and JNK, inactivation of Erk1/2 and Akt were also demonstrated. Although ROS production rather than NO was stimulated, the expression of iNOS and HO-1 were altered after momordin Ic treatment for 4 h. Furthermore, the cytochrome c release, caspase-3 activation, Bax/Bcl-2 expression and PARP cleavage were promoted with LY294002 and U0126 intervention but were blocked by SB203580, SP600125, PI3K activator, NAC and 1,400 W pretreatment, demonstrating the mitochondrial disruption. Furthermore, momordin Ic combination with NAC influenced MAPK, PI3K/Akt and HO-1, iNOS pathways, MAPK and PI3K/Akt pathways also regulated the expression of HO-1 and iNOS. These results indicated that momordin Ic induced apoptosis through oxidative stress-regulated mitochondrial dysfunction involving the MAPK and PI3K-mediated iNOS and HO-1 pathways. Thus, momordin Ic might represent a potential source of anticancer candidate.

  17. Mechanisms of Neuronal Protection against Excitotoxicity, Endoplasmic Reticulum Stress, and Mitochondrial Dysfunction in Stroke and Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Howard Prentice

    2015-01-01

    Full Text Available In stroke and neurodegenerative disease, neuronal excitotoxicity, caused by increased extracellular glutamate levels, is known to result in calcium overload and mitochondrial dysfunction. Mitochondrial deficits may involve a deficiency in energy supply as well as generation of high levels of oxidants which are key contributors to neuronal cell death through necrotic and apoptotic mechanisms. Excessive glutamate receptor stimulation also results in increased nitric oxide generation which can be detrimental to cells as nitric oxide interacts with superoxide to form the toxic molecule peroxynitrite. High level oxidant production elicits neuronal apoptosis through the actions of proapoptotic Bcl-2 family members resulting in mitochondrial permeability transition pore opening. In addition to apoptotic responses to severe stress, accumulation of misfolded proteins and high levels of oxidants can elicit endoplasmic reticulum (ER stress pathways which may also contribute to induction of apoptosis. Two categories of therapeutics are discussed that impact major pro-death events that include induction of oxidants, calcium overload, and ER stress. The first category of therapeutic agent includes the amino acid taurine which prevents calcium overload and is also capable of preventing ER stress by inhibiting specific ER stress pathways. The second category involves N-methyl-D-aspartate receptor (NMDA receptor partial antagonists illustrated by S-Methyl-N, N-diethyldithiocarbamate sulfoxide (DETC-MeSO, and memantine. DETC-MeSO is protective through preventing excitotoxicity and calcium overload and by blocking specific ER stress pathways. Another NMDA receptor partial antagonist is memantine which prevents excessive glutamate excitation but also remarkably allows maintenance of physiological neurotransmission. Targeting of these major sites of neuronal damage using pharmacological agents is discussed in terms of potential therapeutic approaches for

  18. Mechanisms of Neuronal Protection against Excitotoxicity, Endoplasmic Reticulum Stress, and Mitochondrial Dysfunction in Stroke and Neurodegenerative Diseases.

    Science.gov (United States)

    Prentice, Howard; Modi, Jigar Pravinchandra; Wu, Jang-Yen

    2015-01-01

    In stroke and neurodegenerative disease, neuronal excitotoxicity, caused by increased extracellular glutamate levels, is known to result in calcium overload and mitochondrial dysfunction. Mitochondrial deficits may involve a deficiency in energy supply as well as generation of high levels of oxidants which are key contributors to neuronal cell death through necrotic and apoptotic mechanisms. Excessive glutamate receptor stimulation also results in increased nitric oxide generation which can be detrimental to cells as nitric oxide interacts with superoxide to form the toxic molecule peroxynitrite. High level oxidant production elicits neuronal apoptosis through the actions of proapoptotic Bcl-2 family members resulting in mitochondrial permeability transition pore opening. In addition to apoptotic responses to severe stress, accumulation of misfolded proteins and high levels of oxidants can elicit endoplasmic reticulum (ER) stress pathways which may also contribute to induction of apoptosis. Two categories of therapeutics are discussed that impact major pro-death events that include induction of oxidants, calcium overload, and ER stress. The first category of therapeutic agent includes the amino acid taurine which prevents calcium overload and is also capable of preventing ER stress by inhibiting specific ER stress pathways. The second category involves N-methyl-D-aspartate receptor (NMDA receptor) partial antagonists illustrated by S-Methyl-N, N-diethyldithiocarbamate sulfoxide (DETC-MeSO), and memantine. DETC-MeSO is protective through preventing excitotoxicity and calcium overload and by blocking specific ER stress pathways. Another NMDA receptor partial antagonist is memantine which prevents excessive glutamate excitation but also remarkably allows maintenance of physiological neurotransmission. Targeting of these major sites of neuronal damage using pharmacological agents is discussed in terms of potential therapeutic approaches for neurological disorders.

  19. TanshinoneIIA and cryptotanshinone protect against hypoxia-induced mitochondrial apoptosis in H9c2 cells.

    Directory of Open Access Journals (Sweden)

    Hyou-Ju Jin

    Full Text Available Mitochondrial apoptosis pathway is an important target of cardioprotective signalling. Tanshinones, a group of major bioactive compounds isolated from Salvia miltiorrhiza, have been reported with actions against inflammation, oxidative stress, and myocardial ischemia reperfusion injury. However, the actions of these compounds on the chronic hypoxia-related mitochondrial apoptosis pathway have not been investigated. In this study, we examined the effects and molecular mechanisms of two major tanshonones, tanshinone IIA (TIIA and cryptotanshinone (CT on hypoxia induced apoptosis in H9c2 cells. Cultured H9c2 cells were treated with TIIA and CT (0.3 and 3 μΜ 2 hr before and during an 8 hr hypoxic period. Chronic hypoxia caused a significant increase in hypoxia inducible factor 1α expression and the cell late apoptosis rate, which was accompanied with an increase in caspase 3 activity, cytochrome c release, mitochondria membrane potential and expression of pro-apoptosis proteins (Bax and Bak. TIIA and CT (0.3 and 3 μΜ, in concentrations without affecting the cell viability, significantly inhibited the late apoptosis and the changes of caspase 3 activity, cytochrome c release, and mitochondria membrane potential induced by chronic hypoxia. These compounds also suppressed the overexpression of Bax and reduced the ratio of Bax/Bcl-2. The results indicate that TIIA and CT protect against chronic hypoxia induced cell apoptosis by regulating the mitochondrial apoptosis signaling pathway, involving inhibitions of mitochondria hyperpolarization, cytochrome c release and caspase 3 activity, and balancing anti- and pro-apoptotic proteins in Bcl-2 family proteins.

  20. Partial Support Ventilation and Mitochondrial-Targeted Antioxidants Protect against Ventilator-Induced Decreases in Diaphragm Muscle Protein Synthesis.

    Directory of Open Access Journals (Sweden)

    Matthew B Hudson

    Full Text Available Mechanical ventilation (MV is a life-saving intervention in patients in respiratory failure. Unfortunately, prolonged MV results in the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness is significant because inspiratory muscle dysfunction is a risk factor for problematic weaning from MV. Therefore, developing a clinical intervention to prevent MV-induced diaphragm atrophy is important. In this regard, MV-induced diaphragmatic atrophy occurs due to both increased proteolysis and decreased protein synthesis. While efforts to impede MV-induced increased proteolysis in the diaphragm are well-documented, only one study has investigated methods of preserving diaphragmatic protein synthesis during prolonged MV. Therefore, we evaluated the efficacy of two therapeutic interventions that, conceptually, have the potential to sustain protein synthesis in the rat diaphragm during prolonged MV. Specifically, these experiments were designed to: 1 determine if partial-support MV will protect against the decrease in diaphragmatic protein synthesis that occurs during prolonged full-support MV; and 2 establish if treatment with a mitochondrial-targeted antioxidant will maintain diaphragm protein synthesis during full-support MV. Compared to spontaneously breathing animals, full support MV resulted in a significant decline in diaphragmatic protein synthesis during 12 hours of MV. In contrast, diaphragm protein synthesis rates were maintained during partial support MV at levels comparable to spontaneous breathing animals. Further, treatment of animals with a mitochondrial-targeted antioxidant prevented oxidative stress during full support MV and maintained diaphragm protein synthesis at the level of spontaneous breathing animals. We conclude that treatment with mitochondrial-targeted antioxidants or the use of partial-support MV are potential strategies to preserve diaphragm protein synthesis during prolonged MV.

  1. Partial Support Ventilation and Mitochondrial-Targeted Antioxidants Protect against Ventilator-Induced Decreases in Diaphragm Muscle Protein Synthesis.

    Science.gov (United States)

    Hudson, Matthew B; Smuder, Ashley J; Nelson, W Bradley; Wiggs, Michael P; Shimkus, Kevin L; Fluckey, James D; Szeto, Hazel H; Powers, Scott K

    2015-01-01

    Mechanical ventilation (MV) is a life-saving intervention in patients in respiratory failure. Unfortunately, prolonged MV results in the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness is significant because inspiratory muscle dysfunction is a risk factor for problematic weaning from MV. Therefore, developing a clinical intervention to prevent MV-induced diaphragm atrophy is important. In this regard, MV-induced diaphragmatic atrophy occurs due to both increased proteolysis and decreased protein synthesis. While efforts to impede MV-induced increased proteolysis in the diaphragm are well-documented, only one study has investigated methods of preserving diaphragmatic protein synthesis during prolonged MV. Therefore, we evaluated the efficacy of two therapeutic interventions that, conceptually, have the potential to sustain protein synthesis in the rat diaphragm during prolonged MV. Specifically, these experiments were designed to: 1) determine if partial-support MV will protect against the decrease in diaphragmatic protein synthesis that occurs during prolonged full-support MV; and 2) establish if treatment with a mitochondrial-targeted antioxidant will maintain diaphragm protein synthesis during full-support MV. Compared to spontaneously breathing animals, full support MV resulted in a significant decline in diaphragmatic protein synthesis during 12 hours of MV. In contrast, diaphragm protein synthesis rates were maintained during partial support MV at levels comparable to spontaneous breathing animals. Further, treatment of animals with a mitochondrial-targeted antioxidant prevented oxidative stress during full support MV and maintained diaphragm protein synthesis at the level of spontaneous breathing animals. We conclude that treatment with mitochondrial-targeted antioxidants or the use of partial-support MV are potential strategies to preserve diaphragm protein synthesis during prolonged MV.

  2. Intracellular magnesium content changes during mitochondria-mediated apoptosis: in depth study of early events on mitochondrial membrane potential

    Directory of Open Access Journals (Sweden)

    Lucia Merolle

    2014-01-01

    Full Text Available A recent study showed the antitumor activity of a new indole-derivative – MM-67 – inducing mitochondria-mediated apoptosis and a decrease of intracellular magnesium (Mg concentration in HT29 colon cancer cells. Aim of this work was to assess cellular Mg levels throughout MM-67-induced apoptosis from the early to the final stage of the process and to evaluate the correlation with mitochondrial membrane potential (ΔΨm variations. All analysis were performed by flow cytometry: ΔΨm was assessed by using mitochondrial potential sensitive dye DiOC6, while free and total intracellular cation concentrations were assessed by using the commercial probe MagFluo4-AM (Kd=4.7 mM, and the new synthesized DCHQ5 (Kd=8.3 mM, respectively. Our results evidenced that the MM67 induced apoptosis is characterized by a direct correlation between ΔΨ and free intracellular Mg content variations.

  3. The cytotoxic effects of brown Cuban propolis depend on the nemorosone content and may be mediated by mitochondrial uncoupling.

    Science.gov (United States)

    Pardo Andreu, Gilberto L; Reis, Felippe H Z; Dalalio, Felipe M; Nuñez Figueredo, Yanier; Cuesta Rubio, Osmany; Uyemura, Sergio A; Curti, Carlos; Alberici, Luciane C

    2015-02-25

    Three main types of Cuban propolis directly related to their secondary metabolite composition have been identified: brown, red and yellow propolis; the former is majoritarian and is characterized by the presence of nemorosone. In this study, brown Cuban propolis extracts were found cytotoxic against HepG2 cells and primary rat hepatocytes, in close association with the nemorosone contents. In mitochondria isolated from rat liver the extracts displayed uncoupling activity, which was demonstrated by the increase in succinate-supported state 4 respiration rates, dissipation of mitochondrial membrane potential, Ca(2+) release from Ca(2+)-loaded mitochondria, and a marked ATP depletion. As in cells, the degree of such mitotoxic events was closely correlated to the nemorosone content. The propolis extracts that do not contain nemorosone were neither cytotoxic nor mitotoxic, except R-29, whose detrimental effect upon cells and mitochondria could be mediated by its isoflavonoids and chalcones components, well known mitochondrial uncouplers. Our results at least partly unravel the cytotoxic mechanism of Cuban propolis, particularly regarding brown propolis, and raise concerns about the toxicological implication of Cuban propolis consumption. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Mitochondrial aldehyde dehydrogenase mediates vasodilator responses of glyceryl trinitrate and sodium nitrite in the pulmonary vascular bed of the rat.

    Science.gov (United States)

    Badejo, Adeleke M; Hodnette, Chris; Dhaliwal, Jasdeep S; Casey, David B; Pankey, Edward; Murthy, Subramanyam N; Nossaman, Bobby D; Hyman, Albert L; Kadowitz, Philip J

    2010-09-01

    It has been reported that mitochondrial aldehyde dehydrogenase (ALDH2) catalyzes the formation of glyceryl dinitrate and inorganic nitrite from glyceryl trinitrate (GTN), leading to an increase in cGMP and vasodilation in the coronary and systemic vascular beds. However, the role of nitric oxide (NO) formed from nitrite in mediating the response to GTN in the pulmonary vascular bed is uncertain. The purpose of the present study was to determine if nitrite plays a role in mediating vasodilator responses to GTN. In this study, intravenous injections of GTN and sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure under baseline and elevated tone conditions and decreases in systemic arterial pressure in response to GTN and sodium nitrite were attenuated by cyanamide, an ALDH2 inhibitor, whereas responses to the NO donor, sodium nitroprusside (SNP), were not altered. The decreases in pulmonary and systemic arterial pressure in response to GTN and SNP were not altered by allopurinol, an inhibitor of xanthine oxidoreductase, whereas responses to sodium nitrite were attenuated. GTN was approximately 1,000-fold more potent than sodium nitrite in decreasing pulmonary and systemic arterial pressures. These results suggest that ALDH2 plays an important role in the bioactivation of GTN and nitrite in the pulmonary and systemic vascular beds and that the reduction of nitrite to vasoactive NO does not play an important role in mediating vasodilator responses to GTN in the intact chest rat.

  5. Infection-Mediated Priming of Phagocytes Protects against Lethal Secondary Aspergillus fumigatus Challenge

    Science.gov (United States)

    Savers, Amélie; Rasid, Orhan; Parlato, Marianna; Brock, Matthias; Jouvion, Gregory; Ryffel, Bernhard; Cavaillon, Jean-Marc; Eberl, Gerard; Ibrahim-Granet, Oumaïma

    2016-01-01

    Phagocytes restrict the germination of Aspergillus fumigatus conidia and prevent the establishment of invasive pulmonary aspergillosis in immunecompetent mice. Here we report that immunecompetent mice recovering from a primary A. fumigatus challenge are protected against a secondary lethal challenge. Using RAGγc knock-out mice we show that this protection is independent of T, B and NK cells. In protected mice, lung phagocytes are recruited more rapidly and are more efficient in conidial phagocytosis and killing. Protection was also associated with an enhanced expression of CXCR2 and Dectin-1 on bone marrow phagocytes. We also show that protective lung cytokine and chemokine responses are induced more rapidly and with enhanced dynamics in protected mice. Our findings support the hypothesis that following a first encounter with a non-lethal dose of A. fumigatus conidia, the innate immune system is primed and can mediate protection against a secondary lethal infection. PMID:27078879

  6. ATP-dependent mitochondrial porphyrin importer ABCB6 protects against phenylhydrazine toxicity.

    Science.gov (United States)

    Ulrich, Dagny L; Lynch, John; Wang, Yao; Fukuda, Yu; Nachagari, Deepa; Du, Guoqing; Sun, Daxi; Fan, Yiping; Tsurkan, Lyudmila; Potter, Philip M; Rehg, Jerold E; Schuetz, John D

    2012-04-13

    Abcb6 is a mammalian mitochondrial ATP-binding cassette (ABC) transporter that regulates de novo porphyrin synthesis. In previous studies, haploinsufficient (Abcb6(+/-)) embryonic stem cells showed impaired porphyrin synthesis. Unexpectedly, Abcb6(-/-) mice derived from these stem cells appeared phenotypically normal. We hypothesized that other ATP-dependent and/or -independent mechanisms conserve porphyrins. Here, we demonstrate that Abcb6(-/-) mice lack mitochondrial ATP-driven import of coproporphyrin III. Gene expression analysis revealed that loss of Abcb6 results in up-regulation of compensatory porphyrin and iron pathways, associated with elevated protoporphyrin IX (PPIX). Phenylhydrazine-induced stress caused higher mortality in Abcb6(-/-) mice, possibly because of sustained elevation of PPIX and an inability to convert PPIX to heme despite elevated ferrochelatase levels. Therefore, Abcb6 is the sole ATP-dependent porphyrin importer, and loss of Abcb6 produces up-regulation of heme and iron pathways necessary for normal development. However, under extreme demand for porphyrins (e.g. phenylhydrazine stress), these adaptations appear inadequate, which suggests that under these conditions Abcb6 is important for optimal survival.

  7. Imbalance of mitochondrial-nuclear cross talk in isocyanate mediated pulmonary endothelial cell dysfunction

    Directory of Open Access Journals (Sweden)

    Hariom Panwar

    2013-01-01

    Full Text Available Mechanistic investigations coupled with epidemiology, case-control, cohort and observational studies have increasingly linked isocyanate exposure (both chronic and acute with pulmonary morbidity and mortality. Though ascribed for impairment in endothelial cell function, molecular mechanisms of these significant adverse pulmonary outcomes remains poorly understood. As preliminary studies conducted in past have failed to demonstrate a cause-effect relationship between isocyanate toxicity and compromised pulmonary endothelial cell function, we hypothesized that direct exposure to isocyanate may disrupt endothelial structural lining, resulting in cellular damage. Based on this premise, we comprehensively evaluated the molecular repercussions of methyl isocyanate (MIC exposure on human pulmonary arterial endothelial cells (HPAE-26. We examined MIC-induced mitochondrial oxidative stress, pro-inflammatory cytokine response, oxidative DNA damage response and apoptotic index. Our results demonstrate that exposure to MIC, augment mitochondrial reactive oxygen species production, depletion in antioxidant defense enzymes, elevated pro-inflammatory cytokine response and induced endothelial cell apoptosis via affecting the balance of mitochondrial-nuclear cross talk. We herein delineate the first and direct molecular cascade of isocyanate-induced pulmonary endothelial cell dysfunction. The results of our study might portray a connective link between associated respiratory morbidities with isocyanate exposure, and indeed facilitate to discern the exposure-phenotype relationship in observed deficits of pulmonary endothelial cell function. Further, understanding of inter- and intra-cellular signaling pathways involved in isocyanate-induced endothelial damage would not only aid in biomarker identification but also provide potential new avenues to target specific therapeutic interventions.

  8. Sodium butyrate induces DRP1-mediated mitochondrial fusion and apoptosis in human colorectal cancer cells

    OpenAIRE

    Tailor, Dhanir; Hahm, Eun-Ryeong; Kale, Raosaheb K.; Singh, Shivendra V.; Singh, Rana P.

    2013-01-01

    Sodium butyrate (NaBt) is the byproduct of anaerobic microbial fermentation inside the gastro-intestinal tract that could reach upto 20 mM, and has been shown to inhibit the growth of various cancers. Herein, we evaluated its effect on mitochondrial fusion and associated induction of apoptosis in colorectal cancer cells (CRC). NaBt treatment at physiological (1-5 mM) concentrations for 12 and 24 h decreased the cell viability and induced G2-M phase cell cycle arrest in HCT116 (12h) and SW480 ...

  9. Cardioprotection by modulation of mitochondrial respiration during ischemia–reperfusion: Role of apoptosis-inducing factor

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Aijun [Department of Internal Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298 (United States); Department of Anesthesiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan 430030 (China); Szczepanek, Karol; Hu, Ying [Department of Internal Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298 (United States); Lesnefsky, Edward J. [Department of Internal Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298 (United States); Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298 (United States); Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA 23298 (United States); McGuire Department of Veterans Affairs Medical Center, Richmond, VA 23249 (United States); Chen, Qun, E-mail: qchen8@vcu.edu [Department of Internal Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA 23298 (United States)

    2013-06-14

    Highlights: •Blockade of electron transport prevents the loss of AIF from mitochondria during IR. •Blockade of electron transport decreases caspase-independent cell death during IR. •Mitochondrial AIF content is down-regulated in Harlequin mice. •Blockade of electron transport protects Harlequin mouse hearts during IR. •Amobarbital protection is partially dependent on mitochondrial AIF content. -- Abstract: The transient, reversible blockade of electron transport (BET) during ischemia or at the onset of reperfusion protects mitochondria and decreases cardiac injury. Apoptosis inducing factor (AIF) is located within the mitochondrial intermembrane space. A release of AIF from mitochondria into cytosol and nucleus triggers caspase-independent cell death. We asked if BET prevents the loss of AIF from mitochondria as a mechanism of protection in the buffer perfused heart. BET during ischemia with amobarbital, a rapidly reversible inhibitor of mitochondrial complex I, attenuated a release of AIF from mitochondria into cytosol, in turn decreasing the formation of cleaved and activated PARP-1. These results suggest that BET-mediated protection may occur through prevention of the loss of AIF from mitochondria during ischemia–reperfusion. In order to further clarify the role of mitochondrial AIF in BET-mediated protection, Harlequin (Hq) mice, a genetic model with mitochondrial AIF deficiency, were used to test whether BET could still decrease cell injury in Hq mouse hearts during reperfusion. BET during ischemia protected Hq mouse hearts against ischemia–reperfusion injury and improved mitochondrial function in these hearts during reperfusion. Thus, cardiac injury can still be decreased in the presence of down-regulated mitochondrial AIF content. Taken together, BET during ischemia protects both hearts with normal mitochondrial AIF content and hearts with mitochondrial AIF deficiency. Although preservation of mitochondrial AIF content plays a key role in

  10. Protective effect of N-acetylcysteine supplementation on mitochondrial oxidative stress and mitochondrial enzymes in cerebral cortex of streptozotocin-treated diabetic rats.

    Science.gov (United States)

    Kamboj, Sukhdev S; Sandhir, Rajat

    2011-01-01

    Diabetic encephalopathy, characterized by cognitive deficits involves hyperglycemia-induced oxidative stress. Impaired mitochondrial functions might play an important role in accelerated oxidative damage observed in diabetic brain. The aim of the present study was to examine the role of mitochondrial oxidative stress and dysfunctions in the development of diabetic encephalopathy along with the neuroprotective potential of N-acetylcysteine (NAC). Chronic hyperglycemia accentuated mitochondrial oxidative stress in terms of increased ROS production and lipid peroxidation. Significant decrease in Mn-SOD activity along with protein and non-protein thiols was observed in the mitochondria from diabetic brain. The activities of mitochondrial enzymes; NADH dehydrogenase, succinate dehydrogenase and cytochrome oxidase were decreased in the diabetic brain. Increased mitochondrial oxidative stress and dysfunctions were associated with increased cytochrome c and active caspase-3 levels in cytosol. Electron microscopy revealed mitochondrial swelling and chromatin condensation in neurons of diabetic animals. NAC administration, on the other hand was found to significantly improve diabetes-induced biochemical and morphological changes, bringing them closer to the controls. The results from the study provide evidence for the role of mitochondrial oxidative stress and dysfunctions in the development of diabetic encephalopathy and point towards the clinical potential of NAC as an adjuvant therapy to conventional anti-hyperglycemic regimens for the prevention and/or delaying the progression of CNS complications. Copyright © 2010 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  11. High Glutathione and Glutathione Peroxidase-2 Levels Mediate Cell-Type-Specific DNA Damage Protection in Human Induced Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Benjamin Dannenmann

    2015-05-01

    Full Text Available Pluripotent stem cells must strictly maintain genomic integrity to prevent transmission of mutations. In human induced pluripotent stem cells (iPSCs, we found that genome surveillance is achieved via two ways, namely, a hypersensitivity to apoptosis and a very low accumulation of DNA lesions. The low apoptosis threshold was mediated by constitutive p53 expression and a marked upregulation of proapoptotic p53 target genes of the BCL-2 family, ensuring the efficient iPSC removal upon genotoxic insults. Intriguingly, despite the elevated apoptosis sensitivity, both mitochondrial and nuclear DNA lesions induced by genotoxins were less frequent in iPSCs compared to fibroblasts. Gene profiling identified that mRNA expression of several antioxidant proteins was considerably upregulated in iPSCs. Knockdown of glutathione peroxidase-2 and depletion of glutathione impaired protection against DNA lesions. Thus, iPSCs ensure genomic integrity through enhanced apoptosis induction and increased antioxidant defense, contributing to protection against DNA damage.

  12. Fibronectin mediates enhanced wear protection of lubricin during shear.

    Science.gov (United States)

    Andresen Eguiluz, Roberto C; Cook, Sierra G; Brown, Cory N; Wu, Fei; Pacifici, Noah J; Bonassar, Lawrence J; Gourdon, Delphine

    2015-09-14

    Fibronectin (FN) is a glycoprotein found in the superficial zone of cartilage; however, its role in the lubrication and the wear protection of articular joints is unknown. In this work, we have investigated the molecular interactions between FN and various components of the synovial fluid such as lubricin (LUB), hyaluronan (HA), and serum albumin (SA), which are all believed to contribute to joint lubrication. Using a Surface Forces Apparatus, we have measured the normal (adhesion/repulsion) and lateral (friction) forces across layers of individual synovial fluid components physisorbed onto FN-coated mica substrates. Our chief findings are (i) FN strongly tethers LUB and HA to mica, as indicated by high and reversible long-range repulsive normal interactions between surfaces, and (ii) FN and LUB synergistically enhance wear protection of surfaces during shear, as suggested by the structural robustness of FN+LUB layers under pressures up to about 4 MPa. These findings provide new insights into the role of FN in the lubricating properties of synovial fluid components sheared between ideal substrates and represent a significant step forward in our understanding of cartilage damage involved in diseases such as osteoarthritis.

  13. Protective Effect of Unsaturated Fatty Acids on Palmitic Acid-Induced Toxicity in Skeletal Muscle Cells is not Mediated by PPARδ Activation.

    Science.gov (United States)

    Tumova, Jana; Malisova, Lucia; Andel, Michal; Trnka, Jan

    2015-10-01

    Unsaturated free fatty acids (FFA) are able to prevent deleterious effects of saturated FFA in skeletal muscle cells although the mechanisms involved are still not completely understood. FFA act as endogenous ligands of peroxisome proliferator-activated receptors (PPAR), transcription factors regulating the expression of genes involved in lipid metabolism. The aim of this study was to determine whether activation of PPARδ, the most common PPAR subtype in skeletal muscle, plays a role in mediating the protective effect of unsaturated FFA on saturated FFA-induced damage in skeletal muscle cells and to examine an impact on mitochondrial respiration. Mouse C2C12 myotubes were treated for 24 h with different concentrations of saturated FFA (palmitic acid), unsaturated FFA (oleic, linoleic and α-linolenic acid), and their combinations. PPARδ agonist GW501516 and antagonist GSK0660 were also used. Both mono- and polyunsaturated FFA, but not GW501516, prevented palmitic acid-induced cell death. Mono- and polyunsaturated FFA proved to be effective activators of PPARδ compared to saturated palmitic acid; however, in combination with palmitic acid their effect on PPARδ activation was blocked and stayed at the levels observed for palmitic acid alone. Unsaturated FFA at moderate physiological concentrations as well as GW501516, but not palmitic acid, mildly uncoupled mitochondrial respiration. Our results indicate that although unsaturated FFA are effective activators of PPARδ, their protective effect on palmitic acid-induced toxicity is not mediated by PPARδ activation and subsequent induction of lipid regulatory genes in skeletal muscle cells. Other mechanisms, such as mitochondrial uncoupling, may underlie their effect.

  14. Oxidative stress correlates with Wolbachia-mediated antiviral protection in Wolbachia-Drosophila associations.

    Science.gov (United States)

    Wong, Zhee Sheen; Brownlie, Jeremy C; Johnson, Karyn N

    2015-05-01

    Wolbachia mediates antiviral protection in insect hosts and is being developed as a potential biocontrol agent to reduce the spread of insect-vectored viruses. Definition of the molecular mechanism that generates protection is important for understanding the tripartite interaction between host insect, Wolbachia, and virus. Elevated oxidative stress was previously reported for a mosquito line experimentally infected with Wolbachia, suggesting that oxidative stress is important for Wolbachia-mediated antiviral protection. However, Wolbachia experimentally introduced into mosquitoes impacts a range of host fitness traits, some of which are unrelated to antiviral protection. To explore whether elevated oxidative stress is associated with antiviral protection in Wolbachia-infected insects, we analyzed oxidative stress of five Wolbachia-infected Drosophila lines. In flies infected with protective Wolbachia strains, hydrogen peroxide concentrations were 1.25- to 2-fold higher than those in paired fly lines cured of Wolbachia infection. In contrast, there was no difference in the hydrogen peroxide concentrations in flies infected with nonprotective Wolbachia strains compared to flies cured of Wolbachia infection. Using a Drosophila mutant that produces increased levels of hydrogen peroxide, we investigated whether flies with high levels of endogenous reactive oxygen species had altered responses to virus infection and found that flies with high levels of endogenous hydrogen peroxide were less susceptible to virus-induced mortality. Taken together, these results suggest that elevated oxidative stress correlates with Wolbachia-mediated antiviral protection in natural Drosophila hosts.

  15. The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors.

    Science.gov (United States)

    Du, Jing; Zhu, Ming; Bao, Hongkun; Li, Bai; Dong, Yilong; Xiao, Chunjie; Zhang, Grace Y; Henter, Ioline; Rudorfer, Matthew; Vitiello, Benedetto

    2016-11-17

    Numerous studies have linked severe stress to the development of major depressive disorder (MDD) and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol cause oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein-coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid), and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations.

  16. Down-Regulation of NDUFB9 Promotes Breast Cancer Cell Proliferation, Metastasis by Mediating Mitochondrial Metabolism.

    Directory of Open Access Journals (Sweden)

    Liang-Dong Li

    Full Text Available Despite advances in basic and clinical research, metastasis remains the leading cause of death in breast cancer patients. Genetic abnormalities in mitochondria, including mutations affecting complex I and oxidative phosphorylation, are found in breast cancers and might facilitate metastasis. Genes encoding complex I components have significant breast cancer prognostic value. In this study, we used quantitative proteomic analyses to compare a highly metastatic cancer cell line and a parental breast cancer cell line; and observed that NDUFB9, an accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (complex I, was down-regulated in highly metastatic breast cancer cells. Furthermore, we demonstrated that loss of NDUFB9 promotes MDA-MB-231 cells proliferation, migration, and invasion because of elevated levels of mtROS, disturbance of the NAD+/NADH balance, and depletion of mtDNA. We also showed that, the Akt/mTOR/p70S6K signaling pathway and EMT might be involved in this mechanism. Thus, our findings contribute novel data to support the hypothesis that misregulation of mitochondrial complex I NADH dehydrogenase activity can profoundly enhance the aggressiveness of human breast cancer cells, suggesting that complex I deficiency is a potential and important biomarker for further basic research or clinical application.

  17. Aspergillus fumigatus mitochondrial electron transport chain mediates oxidative stress homeostasis, hypoxia responses, and fungal pathogenesis

    Science.gov (United States)

    Grahl, Nora; Dinamarco, Taisa Magnani; Willger, Sven D.; Goldman, Gustavo H.; Cramer, Robert A.

    2012-01-01

    Summary We previously observed that hypoxia is an important component of host microenvironments during pulmonary fungal infections. However, mechanisms of fungal growth in these in vivo hypoxic conditions are poorly understood. Here, we report that mitochondrial respiration is active in hypoxia (1% oxygen) and critical for fungal pathogenesis. We generated Aspergillus fumigatus alternative oxidase (aoxA) and cytochrome C (cycA) null mutants and assessed their ability to tolerate hypoxia, macrophage killing, and virulence. In contrast to ΔaoxA, ΔcycA was found to be significantly impaired in conidia germination, growth in normoxia and hypoxia, and displayed attenuated virulence. Intriguingly, loss of cycA results in increased levels of AoxA activity, which results in increased resistance to oxidative stress, macrophage killing, and long-term persistence in murine lungs. Thus, our results demonstrate a previously unidentified role for fungal mitochondrial respiration in the pathogenesis of aspergillosis, and lay the foundation for future research into its role in hypoxia signaling and adaptation. PMID:22443190

  18. Betulinic Acid Induces Apoptosis in Differentiated PC12 Cells Via ROS-Mediated Mitochondrial Pathway.

    Science.gov (United States)

    Wang, Xi; Lu, Xiaocheng; Zhu, Ronglan; Zhang, Kaixin; Li, Shuai; Chen, Zhongjun; Li, Lixin

    2017-01-25

    Betulinic acid (BA), a pentacyclic triterpene of natural origin, has been demonstrated to have varied biologic activities including anti-viral, anti-inflammatory, and anti-malarial effects; it has also been found to induce apoptosis in many types of cancer. However, little is known about the effect of BA on normal cells. In this study, the effects of BA on normal neuronal cell apoptosis and the mechanisms involved were studied using differentiated PC12 cells as a model. Treatment with 50 μM BA for 24 h apparently induced PC12 cell apoptosis. In the early stage of apoptosis, the level of intracellular reactive oxygen species (ROS) increased. Afterwards, the loss of the mitochondrial membrane potential, the release of cytochrome c and the activation of caspase-3 occurred. Treatment with antioxidants could significantly reduce BA-induced PC12 cell apoptosis. In conclusion, we report for the first time that BA induced the mitochondrial apoptotic pathway in differentiated PC12 cells through ROS.

  19. Enhanced base excision repair capacity in carotid atherosclerosis may protect nuclear DNA but not mitochondrial DNA

    DEFF Research Database (Denmark)

    Skarpengland, Tonje; B. Dahl, Tuva; Skjelland, Mona

    2016-01-01

    Lesional and systemic oxidative stress has been implicated in the pathogenesis of atherosclerosis, potentially leading to accumulation of DNA base lesions within atherosclerotic plaques. Although base excision repair (BER) is a major pathway counteracting oxidative DNA damage, our knowledge on BER...... and accumulation of DNA base lesions in clinical atherosclerosis is scarce. Here, we evaluated the transcriptional profile of a wide spectrum of BER components as well as DNA damage accumulation in atherosclerotic and non-atherosclerotic arteries. BER gene expression levels were analyzed in 162 carotid plaques, 8...... genes in atherosclerosis may contribute to lesional nuclear DNA stability but appears insufficient to maintain mtDNA integrity, potentially influencing mitochondrial function in cells within the atherosclerotic lesion....

  20. Selenium and zinc protect brain mitochondrial antioxidants and electron transport chain enzymes following postnatal protein malnutrition.

    Science.gov (United States)

    Adebayo, Olusegun L; Adenuga, Gbenga A; Sandhir, Rajat

    2016-05-01

    Selenium (Se) and zinc (Zn) are trace elements required for optimal brain functions. Thus, the role of Se and Zn against protein malnutrition induced oxidative stress on mitochondrial antioxidants and electron transport chain (ETC) enzymes from rats' brain were investigated. Normal protein (NP) and low protein (LP) rats were fed with diets containing 16% and 5% casein respectively for a period of 10weeks. Then the rats were supplemented with Se and Zn at a concentration of 0.15mgL(-1) and 227mgL(-1) in drinking water for 3weeks after which the rats were sacrificed. The results obtained from the study showed significant (pmalnutrition induced oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. IL-17A-mediated protection against Acanthamoeba keratitis.

    Science.gov (United States)

    Suryawanshi, Amol; Cao, Zhiyi; Sampson, James F; Panjwani, Noorjahan

    2015-01-15

    Acanthamoeba keratitis (AK) is a very painful and vision-impairing infection of the cornea that is difficult to treat. Although past studies have indicated a critical role of neutrophils and macrophages in AK, the relative contribution of the proinflammatory cytokine, IL-17A, that is essential for migration, activation, and function of these cells into the cornea is poorly defined. Moreover, the role of the adaptive immune response, particularly the contribution of CD4(+) T cell subsets, Th17 and regulatory T cells , in AK is yet to be understood. In this report, using a mouse corneal intrastromal injection-induced AK model, we show that Acanthamoeba infection induces a strong CD4(+) T effector and regulatory T cell response in the cornea and local draining lymph nodes. We also demonstrate that corneal Acanthamoeba infection induces IL-17A expression and that IL-17A is critical for host protection against severe AK pathology. Accordingly, IL-17A neutralization in Acanthamoeba-infected wild-type mice or Acanthamoeba infection of mice lacking IL-17A resulted in a significantly increased corneal AK pathology, increased migration of inflammatory cells at the site of inflammation, and a significant increase in the effector CD4(+) T cell response in draining lymph nodes. Thus, in sharp contrast with other corneal infections such as herpes and Pseudomonas aeruginosa keratitis where IL-17A exacerbates corneal pathology and inflammation, the findings presented in this article suggest that IL-17A production after Acanthamoeba infection plays an important role in host protection against invading parasites.

  2. Testosterone Protects Mitochondrial Function and Regulates Neuroglobin Expression in Astrocytic Cells Exposed to Glucose Deprivation

    OpenAIRE

    Toro-Urrego, Nicolas; Garcia-Segura, Luis M.; Echeverria, Valentina; Barreto, George E.

    2016-01-01

    Testosterone is a hormone that has been shown to confer neuroprotection from different insults affecting the central nervous system (CNS). Testosterone induces this protection by different mechanisms that include the activation of anti-apoptotic pathways that are directly implicated in neuronal survival. However, little attention has been devoted to its actions on glial cells. In the present study, we have assessed whether testosterone exerts protection in a human astrocyte cell model, the T9...

  3. UVR8 mediated plant protective responses under low UV-B radiation leading to photosynthetic acclimation.

    Science.gov (United States)

    Singh, Suruchi; Agrawal, S B; Agrawal, Madhoolika

    2014-08-01

    The UV-B photoreceptor UVR8 regulates the expression of several genes leading to acclimation responses in plants. Direct role of UVR8 in maintaining the photosynthesis is not defined but it is known to increase the expression of some chloroplastic proteins like SIG5 and ELIP. It provides indirect protection to photosynthesis by regulating the synthesis of secondary metabolites and photomorphogenesis. Signaling cascades controlled by UVR8 mediate many protective responses thus promotes plant acclimation against stress and secures its survival.

  4. Nrf2 Protects Against TWEAK-mediated Skeletal Muscle Wasting

    Science.gov (United States)

    Al-Sawaf, Othman; Fragoulis, Athanassios; Rosen, Christian; Kan, Yuet Wai; Sönmez, Tolga Taha; Pufe, Thomas; Wruck, Christoph Jan

    2014-01-01

    Skeletal muscle (SM) regeneration after injury is impaired by excessive inflammation. Particularly, the inflammatory cytokine tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a potent inducer of skeletal muscle wasting and fibrosis. In this study we investigated the role of Nrf2, a major regulator of oxidative stress defence, in SM ischemia/reperfusion (I/R) injury and TWEAK induced atrophy. We explored the time-dependent expression of TWEAK after I/R in SM of Nrf2-wildtype (WT) and knockout (KO) mice. Nrf2-KO mice expressed significant higher levels of TWEAK as compared to WT mice. Consequently, Nrf2-KO mice present an insufficient regeneration as compared to Nrf2-WT mice. Moreover, TWEAK stimulation activates Nrf2 in the mouse myoblast cell line C2C12. This Nrf2 activation inhibits TWEAK induced atrophy in C2C12 differentiated myotubes. In summary, we show that Nrf2 protects SM from TWEAK-induced cell death in vitro and that Nrf2-deficient mice therefore have poorer muscle regeneration.

  5. Gut Microbiota Mediates Protection Against Enteropathy Induced by Indomethacin

    Science.gov (United States)

    Xiao, Xue; Nakatsu, Geicho; Jin, Ye; Wong, Sunny; Yu, Jun; Lau, James Y. W.

    2017-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) can cause significant small bowel injuries. The role of gut microbiota in this NSAID-induced enteropathy is poorly understood. We studied the dynamic changes in gut microbiota following indomethacin administration in mice, and investigated the effects of these adaptive changes on subsequent NSAID-induced enteropathy. The changes in gut microbiota were studied using 16S rRNA sequencing, and the effects of such changes were investigated using antibiotics and a faecal transplantation model. After indomethacin treatment, significant adaptive changes in gut microbiota were observed, including increased abundance of Firmicutes and decreased abundance in that of Bacteroidetes. Depletion of gut microbiota with antibiotics led to a higher mortality (P = 0.0021) in mice compared to controls. Mice pre-transplanted with adaptively changed microbiota showed less small bowel injury and lower levels of pro-inflammatory cytokines when exposed to indomethacin. In summary, this study identifies adaptive changes in the gut microbiota upon indomethacin administration, which can in turn ameliorate further NSAID-induced injury. The heightened mortality with antibiotic depletion of the adaptively changed microbiota suggests its important role in protecting against such injury. This study provides insight for future efforts to target the microbiota as a therapeutic strategy. PMID:28067296

  6. Piroxicam and C-phycocyanin mediated apoptosis in 1,2-dimethylhydrazine dihydrochloride induced colon carcinogenesis: exploring the mitochondrial pathway.

    Science.gov (United States)

    Saini, Manpreet Kaur; Sanyal, Sankar Nath; Vaiphei, Kim

    2012-04-01

    Apoptosis is a synchronized procedure of cell death that is regulated by caspases and proapoptotic proteins. During apoptosis, translocation of cytochrome c, an electron carrier, from mitochondria into the cytosol is regulated by Bcl-2 family members. Cytochrome c in association with an apoptotic protease activating factor (Apaf), a proapoptotic protein essential for cell differentiation and procaspase-9 form the apoptosome complex, which consecutively activates effector caspase, caspase-3, and coordinate the implementation of apoptosis. In the current study, an attempt has been made to gain insight into piroxicam, a traditional nonsteroidal antiinflammatory drug and c-phycocyanin, a biliprotein from Spirulina platensis (cyanobacterium) mediated apoptosis in DMH-induced colon cancer. Male Sprague-Dawley rats were segregated into 5 groups: control, DMH, DMH + piroxicam, DMH + c-phycocyanin, and DMH + piroxicam + c-phycocyanin. Results illustrated that piroxicam and c-phycocyanin treatments stimulate cytochrome c release by downregulating the Bcl-2 (an antiapoptotic protein) expression significantly, while promoting the level of Bax (a proapoptotic protein), thereby activating caspases (caspases-9 and -3) and Apaf-1. The outcomes of the present study clearly signify that piroxicam and c-phycocyanin may mediate mitochondrial-dependent apoptosis in DMH-induced colon cancer. Moreover, apoptosis induction was more apparent in the combination regimen of piroxicam and c-phycocyanin than the individual drugs alone.

  7. Mitochondrial reactive oxygen species regulate the strength of inhibitory GABA-mediated synaptic transmission

    Science.gov (United States)

    Accardi, Michael V.; Daniels, Bryan A.; Brown, Patricia M. G. E.; Fritschy, Jean-Marc; Tyagarajan, Shiva K.; Bowie, Derek

    2014-01-01

    Neuronal communication imposes a heavy metabolic burden in maintaining ionic gradients essential for action potential firing and synaptic signalling. Although cellular metabolism is known to regulate excitatory neurotransmission, it is still unclear whether the brain’s energy supply affects inhibitory signalling. Here we show that mitochondrial-derived reactive oxygen species (mROS) regulate the strength of postsynaptic GABAA receptors at inhibitory synapses of cerebellar stellate cells. Inhibition is strengthened through a mechanism that selectively recruits α3-containing GABAA receptors into synapses with no discernible effect on resident α1-containing receptors. Since mROS promotes the emergence of postsynaptic events with unique kinetic properties, we conclude that newly recruited α3-containing GABAA receptors are activated by neurotransmitter released onto discrete postsynaptic sites. Although traditionally associated with oxidative stress in neurodegenerative disease, our data identify mROS as a putative homeostatic signalling molecule coupling cellular metabolism to the strength of inhibitory transmission.

  8. The novel tetramethylpyrazine bis-nitrone (TN-2) protects against MPTP/MPP+-induced neurotoxicity via inhibition of mitochondrial-dependent apoptosis.

    Science.gov (United States)

    Xu, Daping; Duan, Hongwei; Zhang, Zaijun; Cui, Wei; Wang, Liang; Sun, Yewei; Lang, Ming; Hoi, Pui Man; Han, Yifan; Wang, Yuqiang; Lee, Simon MingYuen

    2014-03-01

    Mitochondrial-dependent apoptosis plays an important role in the degeneration of dopaminergic neurons in Parkinson's disease (PD). Methyl-4-phenyl-1,2,3,6-tetra- hydropyridine (MPTP), the most widely used neurotoxin to simulate PD, is converted to 1-methyl-4-phenylpyridinium (MPP(+)) in vivo. MPP(+) induces excessive intracellular reactive oxygen species (ROS), leading to mitochondrial-dependent apoptosis via sequentially opening mitochondria permeability transition pore (mPTP) to release cytochrome c from mitochondria into cytoplasm and activate pro-apoptotic caspase proteins. We have previously synthesized 2,5-[[(1,1-dimethylethyl)oxidoimino]methyl]-3,6-trimethylpyrazine (TN-2), a novel derivative of the Chinese herb medicine tetramethylpyrazine (TMP). TN-2 is armed with two powerful free radical-scavenging nitrone moieties. TN-2 significantly reversed the loss of dopaminergic neurons in the substantia nigra and the decrease in dopamine level in the striatum induced by MPTP in mice. TN-2 ameliorated the MPTP-induced decrease of brain superoxide dismutase activity and glutathione concentration and increase of brain malondialdehyde. In addition, TN-2 inhibited MPP(+)-induced neuronal damage/apoptosis in primary cerebellum granular neurons (CGNs) and SH-SY5Y cells. TN-2 decreased excessive intracellular ROS, prevented the loss of mitochondrial membrane potential, blocked the release of mitochondrial cytochrome c and inhibited the activation of caspase-3 and caspase-9. Moreover, TN-2 treatment increased the mRNA expression of mitochondrial biogenesis factors peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1 (PGC- 1α and β) and mitochondrial transcription factor A (Tfam) in SH-SY5Y cells and CGNs. These results suggest that TN-2 protects dopaminergic neurons against MPTP/MPP(+)-induced neurotoxicity via the inhibition of mitochondrial-dependent apoptosis and possibly via the activation of mitochondrial biogenesis, indicating that TN-2 is a potential

  9. Iodinated contrast media induce neutrophil apoptosis through a mitochondrial and caspase mediated pathway.

    LENUS (Irish Health Repository)

    Fanning, N F

    2012-02-03

    Iodinated contrast media (ICM) can induce apoptosis (programmed cell death) in renal, myocardial and endothelial cells. Following intravascular injection, circulating immune cells are exposed to high concentrations of ICM. As neutrophils constitutively undergo apoptosis we hypothesized that ICM may adversely affect neutrophil survival. Our aim was to investigate the effect of ICM on neutrophil apoptosis. Neutrophils were isolated from healthy subjects and cultured in vitro with ionic (diatrizoate and ioxaglate) and non-ionic (iohexol and iotrolan) ICM. The effect of ICM on neutrophil apoptosis in both unstimulated and lipopolysaccharide-stimulated neutrophils was determined by annexin V flow cytometry. The influence of physicochemical properties of the different ICM on apoptosis of neutrophils was also studied. We further investigated the effects of ICM on key intracellular signal pathways, including p38 mitogen-activated protein kinase (MAPK) by Western blotting, and mitochondrial depolarization and caspase activity by flow cytometry. Isoiodine concentrations (20 mg ml(-1)) of ionic (diatrizoate 69.6+\\/-2.9%; ioxaglate 58.9+\\/-2.0%) and non-ionic (iohexol 57.3+\\/-2.9%; iotrolan 57.1+\\/-2.6%) ICM significantly induced neutrophil apoptosis over control levels (47.7+\\/-1.4%). The apoptotic effect of ICM was influenced by their chemical structure, with ionic ICM having a more significant (p<0.01) apoptotic effect than non-ionic ICM (p<0.05). Furthermore, ICM reversed the anti-apoptotic effect of lipopolysaccharide (1000 ng ml(-1)) treated neutrophils to control levels (23.0+\\/-3.5% to 61.2+\\/-5.3%; n=4; p<0.05). These agents induce apoptosis through a p38 MAPK independent pathway that results in mitochondrial depolarization, and is dependent on caspase activation. As neutrophils play a central role in host response to infection and injury, ICM, through induction of neutrophil apoptosis, could have a significant deleterious effect on host immune defence and

  10. BID-dependent release of mitochondrial SMAC dampens XIAP-mediated immunity against Shigella.

    Science.gov (United States)

    Andree, Maria; Seeger, Jens M; Schüll, Stephan; Coutelle, Oliver; Wagner-Stippich, Diana; Wiegmann, Katja; Wunderlich, Claudia M; Brinkmann, Kerstin; Broxtermann, Pia; Witt, Axel; Fritsch, Melanie; Martinelli, Paola; Bielig, Harald; Lamkemeyer, Tobias; Rugarli, Elena I; Kaufmann, Thomas; Sterner-Kock, Anja; Wunderlich, F Thomas; Villunger, Andreas; Martins, L Miguel; Krönke, Martin; Kufer, Thomas A; Utermöhlen, Olaf; Kashkar, Hamid

    2014-10-01

    The X-linked inhibitor of apoptosis protein (XIAP) is a potent caspase inhibitor, best known for its anti-apoptotic function in cancer. During apoptosis, XIAP is antagonized by SMAC, which is released from the mitochondria upon caspase-mediated activation of BID. Recent studies suggest that XIAP is involved in immune signaling. Here, we explore XIAP as an important mediator of an immune response against the enteroinvasive bacterium Shigella flexneri, both in vitro and in vivo. Our data demonstrate for the first time that Shigella evades the XIAP-mediated immune response by inducing the BID-dependent release of SMAC from the mitochondria. Unlike apoptotic stimuli, Shigella activates the calpain-dependent cleavage of BID to trigger the release of SMAC, which antagonizes the inflammatory action of XIAP without inducing apoptosis. Our results demonstrate how the cellular death machinery can be subverted by an invasive pathogen to ensure bacterial colonization.

  11. Visnagin protects against doxorubicin-induced cardiomyopathy through modulation of mitochondrial malate dehydrogenase.

    Science.gov (United States)

    Liu, Yan; Asnani, Aarti; Zou, Lin; Bentley, Victoria L; Yu, Min; Wang, You; Dellaire, Graham; Sarkar, Kumar S; Dai, Matthew; Chen, Howard H; Sosnovik, David E; Shin, Jordan T; Haber, Daniel A; Berman, Jason N; Chao, Wei; Peterson, Randall T

    2014-12-10

    Doxorubicin is a highly effective anticancer chemotherapy agent, but its use is limited by its cardiotoxicity. To develop a drug that prevents this toxicity, we established a doxorubicin-induced cardiomyopathy model in zebrafish that recapitulates the cardiomyocyte apoptosis and contractility decline observed in patients. Using this model, we screened 3000 compounds and found that visnagin (VIS) and diphenylurea (DPU) rescue the cardiac performance and circulatory defects caused by doxorubicin in zebrafish. VIS and DPU reduced doxorubicin-induced apoptosis in cultured cardiomyocytes and in vivo in zebrafish and mouse hearts. VIS treatment improved cardiac contractility in doxorubicin-treated mice. Further, VIS and DPU did not reduce the chemotherapeutic efficacy of doxorubicin in several cultured tumor lines or in zebrafish and mouse xenograft models. Using affinity chromatography, we found that VIS binds to mitochondrial malate dehydrogenase (MDH2), a key enzyme in the tricarboxylic acid cycle. As with VIS, treatment with the MDH2 inhibitors mebendazole, thyroxine, and iodine prevented doxorubicin cardiotoxicity, as did treatment with malate itself, suggesting that modulation of MDH2 activity is responsible for VIS' cardioprotective effects. Thus, VIS and DPU are potent cardioprotective compounds, and MDH2 is a previously undescribed, druggable target for doxorubicin-induced cardiomyopathy.

  12. Visnagin protects against doxorubicin-induced cardiomyopathy through modulation of mitochondrial malate dehydrogenase

    Science.gov (United States)

    Liu, Yan; Asnani, Aarti; Zou, Lin; Bentley, Victoria L.; Yu, Min; Wang, You; Dellaire, Graham; Sarkar, Kumar S.; Dai, Matthew; Chen, Howard H.; Sosnovik, David E.; Shin, Jordan T.; Haber, Daniel A.; Berman, Jason N.; Chao, Wei; Peterson, Randall T.

    2015-01-01

    Doxorubicin is a highly effective anti-cancer chemotherapy agent, but its usage is limited by its cardiotoxicity. To develop a drug that prevents the cardiac toxicity of doxorubicin while preserving its anti-tumor potency, we established a doxorubicin-induced cardiomyopathy model in zebrafish that recapitulated the cardiomyocyte apoptosis and contractility decline observed in patients. Using this model, we screened 3000 compounds and discovered that visnagin (VIS) and diphenylurea (DPU) rescue cardiac performance and circulatory defects caused by doxorubicin treatment in zebrafish. VIS and DPU reduced doxorubicin-induced apoptosis in cultured cardiomyocytes and in vivo in zebrafish and mouse hearts. Furthermore, VIS treatment improved cardiac contractility in doxorubicin-treated mice. Importantly, VIS and DPU caused no reduction in the chemotherapeutic efficacy of doxorubicin in several cultured tumor lines or in zebrafish and mouse xenograft models. Using affinity chromatography, we discovered that VIS binds to mitochondrial malate dehydrogenase (MDH2), one of the key enzymes in the tricarboxylic acid cycle. As with VIS, treatment with the MDH2 inhibitors mebendazole, thyroxine, and iodine prevented doxorubicin cardiotoxicity, as did treatment with malate itself, suggesting that modulation of MDH2 activity is responsible for VIS’s cardioprotective effects. Taken together, this study identified VIS and DPU as potent cardioprotective compounds and implicates MDH2 as a previously undescribed, druggable target for doxorubicin-induced cardiomyopathy. PMID:25504881

  13. Recombinant Mitochondrial Manganese Containing Superoxide Dismutase Protects Against Ochratoxin A-Induced Nephrotoxicity.

    Science.gov (United States)

    Ciarcia, Roberto; Damiano, Sara; Squillacioti, Caterina; Mirabella, Nicola; Pagnini, Ugo; Florio, Alessia; Severino, Lorella; Capasso, Giovambattista; Borrelli, Antonella; Mancini, Aldo; Boffo, Silvia; Romano, Gaetano; Giordano, Antonio; Florio, Salvatore

    2016-06-01

    Ochratoxin A (OTA) is a natural mycotoxin, involved in the development of important human and animal diseases. In this work we have studied the role of oxidative stress in the development of OTA nephrotoxicity and the effect of a new recombinant mitochondrial manganese containing superoxide dismutase (rMnSOD) to prevent kidney damage induced by OTA. Blood pressure, glomerular filtration rate and renal histology were analyzed in control rats and in OTA treated rats. In addition, lipid peroxidation, catalase and superoxide dismutase productions were measured. Our data showed that animals treated with OTA presented hypertension and reduction of glomerular filtration rate (GFR). These effects are most probably related to an increase in the reactive oxygen species (ROS) productions. In fact, we have shown that treatment with rMnSOD restored the levels of blood pressure and GFR simultaneously. Moreover, we have noted that OTA induced alteration on glomerular and tubular degeneration and interstitial infiltrates and that use of rMnSOD combined with OTA prevent this renal histological damage confirming the potential therapeutic role in the treatment of rMnSOD OTA nephrotoxicity.

  14. CEP-1, the Caenorhabditis elegans p53 homolog, mediates opposing longevity outcomes in mitochondrial electron transport chain mutants.

    Directory of Open Access Journals (Sweden)

    Aiswarya Baruah

    2014-02-01

    Full Text Available Caenorhabditis elegans CEP-1 and its mammalian homolog p53 are critical for responding to diverse stress signals. In this study, we found that cep-1 inactivation suppressed the prolonged lifespan of electron transport chain (ETC mutants, such as isp-1 and nuo-6, but rescued the shortened lifespan of other ETC mutants, such as mev-1 and gas-1. We compared the CEP-1-regulated transcriptional profiles of the long-lived isp-1 and the short-lived mev-1 mutants and, to our surprise, found that CEP-1 regulated largely similar sets of target genes in the two mutants despite exerting opposing effects on their longevity. Further analyses identified a small subset of CEP-1-regulated genes that displayed distinct expression changes between the isp-1 and mev-1 mutants. Interestingly, this small group of differentially regulated genes are enriched for the "aging" Gene Ontology term, consistent with the hypothesis that they might be particularly important for mediating the distinct longevity effects of CEP-1 in isp-1 and mev-1 mutants. We further focused on one of these differentially regulated genes, ftn-1, which encodes ferritin in C. elegans, and demonstrated that it specifically contributed to the extended lifespan of isp-1 mutant worms but did not affect the mev-1 mutant lifespan. We propose that CEP-1 responds to different mitochondrial ETC stress by mounting distinct compensatory responses accordingly to modulate animal physiology and longevity. Our findings provide insights into how mammalian p53 might respond to distinct mitochondrial stressors to influence cellular and organismal responses.

  15. Development of mitochondrial loop-mediated isothermal amplification for detection of the small liver fluke Opisthorchis viverrini (Opisthorchiidae; Trematoda; Platyhelminthes).

    Science.gov (United States)

    Le, Thanh Hoa; Nguyen, Nga Thi Bich; Truong, Nam Hai; De, Nguyen Van

    2012-04-01

    Mitochondrial DNA sequences offer major advantages over the more usual nuclear targets for loop-mediated isothermal amplification approaches (mito-LAMP) because multiple copies occur in every cell. Four LAMP primers [F3, FIP(F1c+F2), BIP(B1c+B2), and B3] were designed based on the mitochondrial nad1 sequence of Opisthorchis viverrini and used for a highly specific assay (mito-OvLAMP) to distinguish DNA of O. viverrini from that of another opisthorchiid (Clonorchis sinensis) and other trematodes (Haplorchis pumilio, Haplorchis taichui, Fasciola hepatica, and Fasciola gigantica). Conventional PCR was applied using F3/B3 primer pairs to verify the specificity of the primers for O. viverrini DNA templates. All LAMP-positive samples could be detected with the naked eye in sunlight, by gel electrophoresis (stained with ethidium bromide), and by addition of SYBR green I to the product in sunlight or under UV light. Only DNA from O. viverrini yielded amplification products by LAMP (and by PCR verification), and the LAMP limit of detection was as little as 100 fg (10(-4) ng DNA), indicating that this assay is 10 to 100 times more sensitive than PCR. Field testing was done using representative egg and metacercarial samples collected from localities where the fluke is endemic. With the advantages of simplicity, rapidity, sensitivity, and cost effectiveness, mito-OvLAMP is a good tool for molecular detection and epidemiology studies in regions or countries where O. viverrini is endemic, which can lead to more effective control of opisthorchiasis and trematodiasis.

  16. Cracking the Cytotoxicity Code: Apoptotic Induction of 10-Acetylirciformonin B is Mediated through ROS Generation and Mitochondrial Dysfunction

    Directory of Open Access Journals (Sweden)

    Huei-Chuan Shih

    2014-05-01

    Full Text Available A marine furanoterpenoid derivative, 10-acetylirciformonin B (10AB, was found to inhibit the proliferation of leukemia, hepatoma, and colon cancer cell lines, with selective and significant potency against leukemia cells. It induced DNA damage and apoptosis in leukemia HL 60 cells. To fully understand the mechanism behind the 10AB apoptotic induction against HL 60 cells, we extended our previous findings and further explored the precise molecular targets of 10AB. We found that the use of 10AB increased apoptosis by 8.9%–87.6% and caused disruption of mitochondrial membrane potential (MMP by 15.2%–95.2% in a dose-dependent manner, as demonstrated by annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of HL 60 cells with N-acetyl-l-cysteine (NAC, a reactive oxygen species (ROS scavenger, diminished MMP disruption and apoptosis induced by 10AB, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of 10AB. The results of a cell-free system assay indicated that 10AB could act as a topoisomerase catalytic inhibitor through the inhibition of topoisomerase IIα. On the protein level, the expression of the anti-apoptotic proteins Bcl-xL and Bcl-2, caspase inhibitors XIAP and survivin, as well as hexokinase II were inhibited by the use of 10AB. On the other hand, the expression of the pro-apoptotic protein Bax was increased after 10AB treatment. Taken together, our results suggest that 10AB-induced apoptosis is mediated through the overproduction of ROS and the disruption of mitochondrial metabolism.

  17. Epinephrine effects on mitochondrial Krebs cycle are not mediated by typical adrenergic receptors in isolated rat hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, C.; Memon, R.A.; Bessman, S.P. (Univ. of Southern California, Los Angeles (United States))

    1990-02-26

    Oxidation of 2,3-{sup 14}C succinate (suc) carbons in the intra-mitochondrial Krebs cycle was used as a probe to investigate the effects of epinephrine (epi) on isolated rat hepatocytes. Hepatocytes were incubated at 30{degrees}C in Krebs-Henseleit bicarbonate buffer, pH 7.4, with 0.5 mM concentration of each of the 20 natural amino acids, 0.5 mm concentration of each of the 20 natural amino acids, 2,3-{sup 14}C suc and epi (10 uM), phenylephrine (pheni) (10uM) or isoproterenol (10 uM). Epi and phepi caused a significant increase in {sup 14}CO{sub 2} formation from 2,3-{sup 14}C suc, however, phentolamine, an {infinity}-antagonist, failed to inhibit this increased oxidation of suc carbons. Isoproterenol had no effect on hepatocyte metabolism and propranolol, a {beta}-antagonist, failed to cause any reduction in basal or epi stimulated oxidation of 2,3-{sup 14}C carbons. Unlike insulin, neither epi nor phepi had any significant effect on the anabolic utilization of suc carbons for protein or lipid synthesis. Anabolic channeling of Krebs cycle intermediates into amino acids was reduced by epi treatment of hepatocytes. Although epi treatment can enhance the oxidation of substrate through the Krebs cycle reactions, only insulin is capable of channeling these substrates into anabolic reactions. Data presented also suggest that epi effects on mitochondrial Krebs cycle oxidation are mediated through an atypical {infinity}-adrenergic receptor which is unresponsive to inhibition by non-selective {infinity}-antagonists.

  18. Mediator-assisted Simultaneous probing of Cytosolic and Mitochondrial Redox activity in living cells

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Spegel, Christer; Kostesha, Natalie

    2009-01-01

    This work describes an electron transfer mediator-assisted amperometric flow injection method for assessing redox enzyme activity in different subcellular compartments of the phosphoglucose isomerase deletion mutant strain of Saccharomyces cerevisiae, EBY44. The method is demonstrated using the f...

  19. Parental Mediation Regarding Children's Smartphone Use: Role of Protection Motivation and Parenting Style.

    Science.gov (United States)

    Hwang, Yoori; Choi, Inho; Yum, Jung-Yoon; Jeong, Se-Hoon

    2017-06-01

    Parental mediation is a type of behavior that could protect children against the negative uses and effects of smartphones. Based on protection motivation theory, this research (a) predicted parental mediation based on parents' threat and efficacy perceptions and (b) predicted threat and efficacy perceptions based on parenting styles and parents' addiction to smartphone use. An online survey of 448 parents of fourth to sixth graders was conducted. Results showed that both restrictive and active parental mediation were predicted by perceived severity, response efficacy, and self-efficacy. With regard to parenting styles, (a) authoritative parenting was positively related to perceived severity as well as response- and self-efficacy, whereas (b) permissive parenting was negatively related to self-efficacy. In addition, parents' addiction was a negative predictor of perceived severity, but a positive predictor of perceived susceptibility.

  20. Protective features of resveratrol on human spermatozoa cryopreservation may be mediated through 5' AMP-activated protein kinase activation.

    Science.gov (United States)

    Shabani Nashtaei, M; Amidi, F; Sedighi Gilani, M A; Aleyasin, A; Bakhshalizadeh, Sh; Naji, M; Nekoonam, S

    2017-03-01

    Biochemical and physical modifications during the freeze-thaw process adversely influence the restoration of energy-dependent sperm functions required for fertilization. Resveratrol, a phytoalexin, has been introduced to activate 5' AMP-activated protein kinase which is a cell energy sensor and a cell metabolism regulator. The cryoprotection of resveratrol on sperm cryoinjury via activation of AMP-activated protein kinase also remains to be elucidated. Our aim, thus, was to investigate: (i) the presence and intracellular localization of AMP-activated protein kinase protein; (ii) whether resveratrol may exert a protective effect on certain functional properties of fresh and post-thaw human spermatozoa through modulation of AMP-activated protein kinase. Spermatozoa from normozoospermic men were incubated with or without different concentrations of Compound C as an AMP-activated protein kinase inhibitor or resveratrol as an AMP-activated protein kinase activator for different lengths of time and were then cryopreserved. AMP-activated protein kinase is expressed essentially in the entire flagellum and the post-equatorial region. Viability of fresh spermatozoa was not significantly affected by the presence of Compound C or resveratrol. However, although Compound C caused a potent inhibition of spermatozoa motility parameters, resveratrol did not induce negative effect, except a significant reduction in motility at 25 μm for 1 h. Furthermore, resveratrol significantly increased AMP-activated protein kinase phosphorylation and mitochondrial membrane potential and decreased reactive oxygen species and apoptosis-like changes in frozen-thawed spermatozoa. Nevertheless, it was not able to compensate decreased sperm viability and motility parameters following cryopreservation. In contrast, Compound C showed opposite effects to resveratrol on AMP-activated protein kinase phosphorylation, reactive oxygen species, apoptosis-like changes, mitochondrial membrane potential, and

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

    Science.gov (United States)

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

    2000-10-01

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

  2. Folate-mediated mitochondrial targeting with doxorubicin-polyrotaxane nanoparticles overcomes multidrug resistance

    Science.gov (United States)

    Yan, Fengjiao; Sun, Mingna; Du, Lingran; Peng, Wei; Li, Qiuli; Feng, Yinghong; Zhou, Yi

    2015-01-01

    Resistance to treatment with anticancer drugs is a significant obstacle and a fundamental cause of therapeutic failure in cancer therapy. Functional doxorubicin (DOX) nanoparticles for targeted delivery of the classical cytotoxic anticancer drug DOX to tumor cells, using folate-terminated polyrotaxanes along with dequalinium, have been developed and proven to overcome this resistance due to specific molecular features, including a size of approximately 101 nm, a zeta potential of 3.25 mV and drug-loading content of 18%. Compared with free DOX, DOX hydrochloride, DOX nanoparticles, and targeted DOX nanoparticles, the functional DOX nanoparticles exhibited the strongest anticancer efficacy in vitro and in the drug-resistant MCF-7/ Adr (DOX) xenograft tumor model. More specifically, the nanoparticles significantly increased the intracellular uptake of DOX, selectively accumulating in mitochondria and the endoplasmic reticulum after treatment, with release of cytochrome C as a result. Furthermore, the caspase-9 and caspase-3 cascade was activated by the functional DOX nanoparticles through upregulation of the pro-apoptotic proteins Bax and Bid and suppression of the antiapoptotic protein Bcl-2, thereby enhancing apoptosis by acting on the mitochondrial signaling pathways. In conclusion, functional DOX nanoparticles may provide a strategy for increasing the solubility of DOX and overcoming multidrug-resistant cancers. PMID:25605018

  3. Norcantharidin induced DU145 cell apoptosis through ROS-mediated mitochondrial dysfunction and energy depletion.

    Science.gov (United States)

    Shen, Bo; He, Pei-Jie; Shao, Chun-Lin

    2013-01-01

    Norcantharidin (NCTD), a demethylated analog of cantharidin derived from blister beetles, has attracted considerable attentions in recent years due to their definitely toxic properties and the noteworthy advantages in stimulating bone marrow and increasing the peripheral leukocytes. Hence, it is worth studying the anti-tumor effect of NCTD on human prostate cancer cells DU145. It was found that after the treatment of NCTD with different concentrations (25-100 μM), the cell proliferation was significantly inhibited, which led to the appearance of micronucleus (MN). Moreover, the cells could be killed in a dose-/time-dependent manner along with the reduction of PCNA (proliferating cell nuclear antigen) expression, destruction of mitochondrial membrane potential (MMP), down-regulation of MnSOD, induction of ROS, depletion of ATP, and activation of AMPK (Adenosine 5'-monophosphate -activated protein kinase) . In addition, a remarkable release of cytochrome c was found in the cells exposed to 100 μM NCTD and exogenous SOD-PEG could eliminate the generation of NCTD-induced MN. In conclusion, our studies indicated that NCTD could induce the collapse of MMP and mitochondria dysfunction. Accumulation of intercellular ROS could eventually switch on the apoptotic pathway by causing DNA damage and depleting ATP.

  4. Norcantharidin induced DU145 cell apoptosis through ROS-mediated mitochondrial dysfunction and energy depletion.

    Directory of Open Access Journals (Sweden)

    Bo Shen

    Full Text Available Norcantharidin (NCTD, a demethylated analog of cantharidin derived from blister beetles, has attracted considerable attentions in recent years due to their definitely toxic properties and the noteworthy advantages in stimulating bone marrow and increasing the peripheral leukocytes. Hence, it is worth studying the anti-tumor effect of NCTD on human prostate cancer cells DU145. It was found that after the treatment of NCTD with different concentrations (25-100 μM, the cell proliferation was significantly inhibited, which led to the appearance of micronucleus (MN. Moreover, the cells could be killed in a dose-/time-dependent manner along with the reduction of PCNA (proliferating cell nuclear antigen expression, destruction of mitochondrial membrane potential (MMP, down-regulation of MnSOD, induction of ROS, depletion of ATP, and activation of AMPK (Adenosine 5'-monophosphate -activated protein kinase . In addition, a remarkable release of cytochrome c was found in the cells exposed to 100 μM NCTD and exogenous SOD-PEG could eliminate the generation of NCTD-induced MN. In conclusion, our studies indicated that NCTD could induce the collapse of MMP and mitochondria dysfunction. Accumulation of intercellular ROS could eventually switch on the apoptotic pathway by causing DNA damage and depleting ATP.

  5. Role of SIRT1-mediated mitochondrial and Akt pathways in glioblastoma cell death induced by Cotinus coggygria flavonoid nanoliposomes

    Directory of Open Access Journals (Sweden)

    Wang G

    2015-08-01

    phosphorylated p53. Together, these results indicated SIRT1/p53-mediated cell death was induced by CCF-NLs, but not by extracellular signal-regulated kinase, in DBTRG-05MG cells. Overall, this study suggested caspase-dependent activation of both the intrinsic and extrinsic signaling pathways, probably through blockade of the SIRT1/p53-mediated mitochondrial and Akt pathways to exert the proapoptotic effect of CCF-NLs in DBTRG-05MG GBM cells. Keywords: Cotinus coggygria flavonoid nanoliposomes, cell death, SIRT1, mitochondrial, PI3K/Akt pathway

  6. Mitochondrial p53 mediates a transcription-independent regulation of cell respiration and interacts with the mitochondrial F₁F₀-ATP synthase

    Science.gov (United States)

    Bergeaud, Marie; Mathieu, Lise; Guillaume, Arnaud; Moll, Ute M; Mignotte, Bernard; Le Floch, Nathalie; Vayssière, Jean-Luc; Rincheval, Vincent

    2013-01-01

    We and others previously reported that endogenous p53 can be located at mitochondria in the absence of stress, suggesting that p53 has a role in the normal physiology of this organelle. The aim of this study was to characterize in unstressed cells the intramitochondrial localization of p53 and identify new partners and functions of p53 in mitochondria. We find that the intramitochondrial pool of p53 is located in the intermembrane space and the matrix. Of note, unstressed HCT116 p53+/+ cells simultaneously show increased O₂ consumption and decreased mitochondrial superoxide production compared with their p53-null counterpart. This data was confirmed by stable H1299 cell lines expressing low levels of p53 specifically targeted to the matrix. Using immunoprecipitation and mass spectrometry, we identified the oligomycin sensitivity-conferring protein (OSCP), a subunit of the F₁F₀-ATP synthase complex, as a new partner of endogenous p53, specifically interacting with p53 localized in the matrix. Interestingly, this interaction seems implicated in mitochondrial p53 localization. Moreover, p53 localized in the matrix promotes the assembly of F₁F₀-ATP synthase. Taking into account that deregulations of mitochondrial respiration and reactive oxygen species production are tightly linked to cancer development, we suggest that mitochondrial p53 may be an important regulator of normal mitochondrial and cellular physiology, potentially exerting tumor suppression activity inside mitochondria. PMID:23966169

  7. Mitochondrial p53 mediates a transcription-independent regulation of cell respiration and interacts with the mitochondrial F₁F0-ATP synthase.

    Science.gov (United States)

    Bergeaud, Marie; Mathieu, Lise; Guillaume, Arnaud; Moll, Ute M; Mignotte, Bernard; Le Floch, Nathalie; Vayssière, Jean-Luc; Rincheval, Vincent

    2013-09-01

    We and others previously reported that endogenous p53 can be located at mitochondria in the absence of stress, suggesting that p53 has a role in the normal physiology of this organelle. The aim of this study was to characterize in unstressed cells the intramitochondrial localization of p53 and identify new partners and functions of p53 in mitochondria. We find that the intramitochondrial pool of p53 is located in the intermembrane space and the matrix. Of note, unstressed HCT116 p53(+/+) cells simultaneously show increased O₂ consumption and decreased mitochondrial superoxide production compared with their p53-null counterpart. This data was confirmed by stable H1299 cell lines expressing low levels of p53 specifically targeted to the matrix. Using immunoprecipitation and mass spectrometry, we identified the oligomycin sensitivity-conferring protein (OSCP), a subunit of the F₁F₀-ATP synthase complex, as a new partner of endogenous p53, specifically interacting with p53 localized in the matrix. Interestingly, this interaction seems implicated in mitochondrial p53 localization. Moreover, p53 localized in the matrix promotes the assembly of F₁F₀-ATP synthase. Taking into account that deregulations of mitochondrial respiration and reactive oxygen species production are tightly linked to cancer development, we suggest that mitochondrial p53 may be an important regulator of normal mitochondrial and cellular physiology, potentially exerting tumor suppression activity inside mitochondria.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Lemasters, John J., E-mail: JJLemasters@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC (United States)

    2013-11-15

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

  9. Canonical Wnt signaling protects hippocampal neurons from Aβ oligomers: role of non-canonical Wnt-5a/Ca2+ in mitochondrial dynamics

    Science.gov (United States)

    Silva-Alvarez, Carmen; Arrázola, Macarena S.; Godoy, Juan A.; Ordenes, Daniela; Inestrosa, Nibaldo C.

    2013-01-01

    Alzheimer's disease (AD) is the most common type of age-related dementia. The disease is characterized by a progressive loss of cognitive abilities, severe neurodegeneration, synaptic loss and mitochondrial dysfunction. The Wnt signaling pathway participates in the development of the central nervous system and growing evidence indicates that Wnts also regulate the function of the adult nervous system. We report here, that indirect activation of canonical Wnt/β-catenin signaling using Bromoindirubin-30-Oxime (6-BIO), an inhibitor of glycogen synthase kinase-3β, protects hippocampal neurons from amyloid-β (Aβ) oligomers with the concomitant blockade of neuronal apoptosis. More importantly, activation with Wnt-5a, a non-canonical Wnt ligand, results in the modulation of mitochondrial dynamics, preventing the changes induced by Aβ oligomers (Aβo) in mitochondrial fission-fusion dynamics and modulates Bcl-2 increases induced by oligomers. The canonical Wnt-3a ligand neither the secreted Frizzled-Related Protein (sFRP), a Wnt scavenger, did not prevent these effects. In contrast, some of the Aβ oligomer effects were blocked by Ryanodine. We conclude that canonical Wnt/β-catenin signaling controls neuronal survival, and that non-canonical Wnt/Ca2+signaling modulates mitochondrial dysfunction. Since mitochondrial dysfunction is present in neurodegenerative diseases, the therapeutic possibilities of the activation of Wnt signaling are evident. PMID:23805073

  10. Mitochondrial fusion, fission, and mitochondrial toxicity.

    Science.gov (United States)

    Meyer, Joel N; Leuthner, Tess C; Luz, Anthony L

    2017-08-05

    Mitochondrial dynamics are regulated by two sets of opposed processes: mitochondrial fusion and fission, and mitochondrial biogenesis and degradation (including mitophagy), as well as processes such as intracellular transport. These processes maintain mitochondrial homeostasis, regulate mitochondrial form, volume and function, and are increasingly understood to be critical components of the cellular stress response. Mitochondrial dynamics vary based on developmental stage and age, cell type, environmental factors, and genetic background. Indeed, many mitochondrial homeostasis genes are human disease genes. Emerging evidence indicates that deficiencies in these genes often sensitize to environmental exposures, yet can also be protective under certain circumstances. Inhibition of mitochondrial dynamics also affects elimination of irreparable mitochondrial DNA (mtDNA) damage and transmission of mtDNA mutations. We briefly review the basic biology of mitodynamic processes with a focus on mitochondrial fusion and fission, discuss what is known and unknown regarding how these processes respond to chemical and other stressors, and review the literature on interactions between mitochondrial toxicity and genetic variation in mitochondrial fusion and fission genes. Finally, we suggest areas for future research, including elucidating the full range of mitodynamic responses from low to high-level exposures, and from acute to chronic exposures; detailed examination of the physiological consequences of mitodynamic alterations in different cell types; mechanism-based testing of mitotoxicant interactions with interindividual variability in mitodynamics processes; and incorporating other environmental variables that affect mitochondria, such as diet and exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. COX19 mediates the transduction of a mitochondrial redox signal from SCO1 that regulates ATP7A-mediated cellular copper efflux

    Science.gov (United States)

    Leary, Scot C.; Cobine, Paul A.; Nishimura, Tamiko; Verdijk, Robert M.; de Krijger, Ronald; de Coo, René; Tarnopolsky, Mark A.; Winge, Dennis R.; Shoubridge, Eric A.

    2013-01-01

    SCO1 and SCO2 are metallochaperones whose principal function is to add two copper ions to the catalytic core of cytochrome c oxidase (COX). However, affected tissues of SCO1 and SCO2 patients exhibit a combined deficiency in COX activity and total copper content, suggesting additional roles for these proteins in the regulation of cellular copper homeostasis. Here we show that both the redox state of the copper-binding cysteines of SCO1 and the abundance of SCO2 correlate with cellular copper content and that these relationships are perturbed by mutations in SCO1 or SCO2, producing a state of apparent copper overload. The copper deficiency in SCO patient fibroblasts is rescued by knockdown of ATP7A, a trans-Golgi, copper-transporting ATPase that traffics to the plasma membrane during copper overload to promote efflux. To investigate how a signal from SCO1 could be relayed to ATP7A, we examined the abundance and subcellular distribution of several soluble COX assembly factors. We found that COX19 partitions between mitochondria and the cytosol in a copper-dependent manner and that its knockdown partially rescues the copper deficiency in patient cells. These results demonstrate that COX19 is necessary for the transduction of a SCO1-dependent mitochondrial redox signal that regulates ATP7A-mediated cellular copper efflux. PMID:23345593

  12. Ginsenoside Rd attenuates mitochondrial permeability transition and cytochrome C release in isolated spinal cord mitochondria: involvement of kinase-mediated pathways.

    Science.gov (United States)

    Zhou, Jin-Song; Wang, Jiang-Feng; He, Bao-Rong; Cui, Yong-Sheng; Fang, Xiang-Yi; Ni, Jian-Long; Chen, Jie; Wang, Kun-Zheng

    2014-06-03

    Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca2+ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(P)H matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca2+ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca2+ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg) protected spinal cord mitochondria against Ca2+ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.

  13. Ginsenoside Rd Attenuates Mitochondrial Permeability Transition and Cytochrome c Release in Isolated Spinal Cord Mitochondria: Involvement of Kinase-Mediated Pathways

    Directory of Open Access Journals (Sweden)

    Jin-Song Zhou

    2014-06-01

    Full Text Available Ginsenoside Rd (Rd, one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca2+ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(PH matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca2+ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca2+ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg protected spinal cord mitochondria against Ca2+ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.

  14. Hispidin produced from Phellinus linteus protects against peroxynitrite-mediated DNA damage and hydroxyl radical generation.

    Science.gov (United States)

    Chen, Wei; Feng, Lina; Huang, Zhaoyi; Su, Hongming

    2012-09-30

    Oxidative stress plays an important role in the progression of many chronic diseases including cardiovascular diseases, diabetes, cancer and neurodegenerative disorders. One such mediator of oxidative stress is peroxynitrite, which is highly toxic to cultured neurons and astrocytes, and has been reported to be involved in the pathogenesis of various types of neuronal diseases. Therefore, searching for natural compounds with peroxynitrite-scavenging activity might be an effective therapy for peroxynitrite-mediated cytotoxicity. Hispidin, a phenolic compound from Phellinus linteus (a medicinal mushroom), has been shown to possess strong antioxidant, anticancer, and antidiabetic properties. However, the astrocyte protective efficacy of hispidin has been not examined. This study was undertaken to investigate whether the astrocyte protective effect of hispidin is associated with inhibition of peroxynitrite-induced DNA damage, a critical event leading to peroxynitrite-mediated cytotoxicity. Our results showed that peroxynitrite can cause DNA damage in φX-174 plasmid DNA and rat primary astrocytes. The presence of hispidin (10-20 μg/ml) was found to significantly inhibit peroxynitrite-induced DNA damage and cytotoxicity. EPR spectroscopy demonstrated that the formation of DMPO-hydroxyl radical adduct (DMPO-OH) from peroxynitrite, and that hispidin potently diminished the adduct signal in a concentration-dependent manner. Taken together, these results demonstrate for the first time that hispidin can protect against peroxynitrite-mediated cytotoxicity, DNA damage and hydroxyl radical formation.

  15. Delphinidin-3-glucoside protects against oxidized low-density lipoprotein-induced mitochondrial dysfunction in vascular endothelial cells via the sodium-dependent glucose transporter SGLT1.

    Directory of Open Access Journals (Sweden)

    Xin Jin

    Full Text Available Delphinidin-3-glucoside (Dp is a member of a family of bioactive compounds known as anthocyanins that occur naturally in pigmented plants and are known to ameliorate oxidative stress. Previous studies have showed that Dp decreased oxidative stress in vascular endothelial cells, however, the underlying mechanisms remain largely unknown. In the present study, we showed that pretreatment with Dp significantly suppressed oxidized low-density lipoprotein (oxLDL-induced cell proliferation inhibition and apoptosis in primary human umbilical vein endothelial cells (HUVECs. Also, Dp pretreatment attenuated oxLDL-induced mitochondrial dysfunction via decreased reactive oxygen species (ROS and superoxide anion generation, thereby repressing mitochondrial membrane potential and closing mitochondrial permeability transition pore. Furthermore, in vitro and in vivo data showed that Dp was transported into endothelial cells in a temperature, concentration, and time-dependent manner via the sodium-dependent glucose transporter (SGLT1. Suppression of SGLT1 by its substrate glucose, its inhibitor phlorizin or SGLT1 siRNA blocked Dp transportation. Repression of SGLT1 significantly inhibited Dp function of ameliorating mitochondrial dysfunction induced by pro-apoptotic factors (Apoptosis-inducing factor, Cytochrome c, Caspase-3 and Bax/Bcl-2 ratio. Taken together, our data indicate that Dp protects VECs via the SGLT1-ROS-mitochodria pathway. This new insight may help to elucidate the molecular mechanisms underlying the vascular protection afforded by Dp, and anthocyanins in general, in the context of prevention of endothelial dysfunction and atherosclerosis.

  16. Protective Effect of Plantago major Extract against t-BOOH-Induced Mitochondrial Oxidative Damage and Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Joyce C. Mello

    2015-09-01

    Full Text Available Plantago major L. produces several chemical substances with anti-inflammatory and analgesic activities and its use in the treatment of oral and throat inflammation in popular medicine is well described. In this study, the antioxidant potential of the Plantago major hydroethanolic extract was screened and its protective action was evaluated against t-BOOH-induced oxidative stress. The extract was obtained by fractionated percolation using 50% ethanolic solution and, after drying, suspended in dimethyl sulfoxide. The chromatographic profile of crude extract was obtained with the identification of some phytochemical markers and the total phenols and flavonoids were quantified. The scavenger activity against DPPH (1,1-diphenyl-2-picrylhydrazyl radicals was determined and the antioxidant activity in biological systems was evaluated in isolated rat liver mitochondria and HepG2 cells. The extract exhibited a significant free radical scavenger activity at 0.1 mg/mL, and decreased the ROS (reactive oxygen species generation in succinate-energized mitochondria. Such an effect was associated with the preservation of the intrinsic antioxidant defenses (reduced glutathione and NAD(PH against the oxidation by t-BOOH, and also to the protection of membranes from lipid oxidation. The cytoprotective effect of PmHE against t-BOOH induced cell death was also shown. These findings contribute to the understanding of the health benefits attributed to P. major.

  17. Protective Effect of Plantago major Extract against t-BOOH-Induced Mitochondrial Oxidative Damage and Cytotoxicity.

    Science.gov (United States)

    Mello, Joyce C; Gonzalez, Mariano V D; Moraes, Vivian W R; Prieto, Tatiana; Nascimento, Otaciro R; Rodrigues, Tiago

    2015-09-25

    Plantago major L. produces several chemical substances with anti-inflammatory and analgesic activities and its use in the treatment of oral and throat inflammation in popular medicine is well described. In this study, the antioxidant potential of the Plantago major hydroethanolic extract was screened and its protective action was evaluated against t-BOOH-induced oxidative stress. The extract was obtained by fractionated percolation using 50% ethanolic solution and, after drying, suspended in dimethyl sulfoxide. The chromatographic profile of crude extract was obtained with the identification of some phytochemical markers and the total phenols and flavonoids were quantified. The scavenger activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals was determined and the antioxidant activity in biological systems was evaluated in isolated rat liver mitochondria and HepG2 cells. The extract exhibited a significant free radical scavenger activity at 0.1 mg/mL, and decreased the ROS (reactive oxygen species) generation in succinate-energized mitochondria. Such an effect was associated with the preservation of the intrinsic antioxidant defenses (reduced glutathione and NAD(P)H) against the oxidation by t-BOOH, and also to the protection of membranes from lipid oxidation. The cytoprotective effect of PmHE against t-BOOH induced cell death was also shown. These findings contribute to the understanding of the health benefits attributed to P. major.

  18. Matrine inhibits proliferation and induces apoptosis via BID-mediated mitochondrial pathway in esophageal cancer cells.

    Science.gov (United States)

    Wang, Qiao; Du, Haoxin; Geng, Guojun; Zhou, Huan; Xu, Minying; Cao, Hanwei; Zhang, Bing; Song, Gang; Hu, Tianhui

    2014-05-01

    Matrine, as a member of Sophora family, is an alkaloid found in plants, and produces plethora pharmacological effects, including anti-cancer effects. However, the mechanism involved remains largely unknown. This study is conducted to investigate the anti-cancer mechanisms of matrine in human esophageal cancer in vitro and in vivo. In human esophageal cancer cell Eca-109, matrine significantly decreased the cell viability in a dose-dependent manner, and induced apoptosis as well as cell cycle arrest in G0/G1 phase by up-regulation of P53 and P21. The expression of several apoptosis-related proteins in cells and tumor tissues were evaluated by Western blot analysis. We found that matrine induced cell apoptosis by down-regulation of the ratio of BCL-2/BID and increasing activation of caspase-9. Further studies indicated that matrine induced apoptosis of Eca-109 was through the mitochondria-mediated internal pathway, but not by death receptor-mediated extrinsic apoptotic pathway, which was confirmed by the fact that Bid translocated from the nucleus to mitochondria during the process of the apoptosis induced by matrine. In vivo study found that matrine effectively inhibited the tumor formation of Eca-109 cells in nude mice. Our study suggests that matrine could serve as a potential novel agent from natural products to treat esophageal cancer.

  19. Citrate-release-mediated aluminum resistance is coupled to the inducible expression of mitochondrial citrate synthase gene in Paraserianthes falcataria.

    Science.gov (United States)

    Osawa, Hiroki; Kojima, Katsumi

    2006-05-01

    Aluminum (Al) resistance in some leguminous plants is achieved by enhanced citrate release from roots. Enhancement requires several hours for complete activation and is postulated to involve Al-responsive genes or components. We examined the mechanism of Al-induced citrate release by studying the relationship between citrate release and expression of the mitochondrial citrate synthase (mCS) gene in three leguminous trees. Root elongation in Leucaena leucocephala (Lam.) de Wit was arrested within 24 h by 30 microM Al, whereas root elongation in Paraserianthes falcataria (L.) Neilson and Acacia mangium Willd. was inhibited mangium maintained enhanced release and accumulation of citrate for at least 28 days in response to Al treatment. Aluminum increased the accumulation of mCS transcripts in P. falcataria roots, but not in L. leucocephala roots, and thus up-regulation decreased following removal of Al. Lanthanum did not alter the expression level of mCS. Aluminum increased mCS activity concomitantly with enhanced mCS gene expression in P. falcataria, whereas it did not affect mCS activity in L. leucocephala. Aluminum content in root apices of P. falcataria was increased by cycloheximide, supporting the idea that de novo synthesis of proteins is a prerequisite for Al resistance. Our findings suggest that Al-inducible expression of mCS coupled with enhanced citrate release mediates Al resistance in P. falcataria.

  20. The mitochondrial 2-oxoglutarate carrier is part of a metabolic pathway that mediates glucose- and glutamine-stimulated insulin secretion.

    Science.gov (United States)

    Odegaard, Matthew L; Joseph, Jamie W; Jensen, Mette V; Lu, Danhong; Ilkayeva, Olga; Ronnebaum, Sarah M; Becker, Thomas C; Newgard, Christopher B

    2010-05-28

    Glucose-stimulated insulin secretion from pancreatic islet beta-cells is dependent in part on pyruvate cycling through the pyruvate/isocitrate pathway, which generates cytosolic alpha-ketoglutarate, also known as 2-oxoglutarate (2OG). Here, we have investigated if mitochondrial transport of 2OG through the 2-oxoglutarate carrier (OGC) participates in control of nutrient-stimulated insulin secretion. Suppression of OGC in clonal pancreatic beta-cells (832/13 cells) and isolated rat islets by adenovirus-mediated delivery of small interfering RNA significantly decreased glucose-stimulated insulin secretion. OGC suppression also reduced insulin secretion in response to glutamine plus the glutamate dehydrogenase activator 2-amino-2-norbornane carboxylic acid. Nutrient-stimulated increases in glucose usage, glucose oxidation, glutamine oxidation, or ATP:ADP ratio were not affected by OGC knockdown, whereas suppression of OGC resulted in a significant decrease in the NADPH:NADP(+) ratio during stimulation with glucose but not glutamine + 2-amino-2-norbornane carboxylic acid. Finally, OGC suppression reduced insulin secretion in response to a membrane-permeant 2OG analog, dimethyl-2OG. These data reveal that the OGC is part of a mechanism of fuel-stimulated insulin secretion that is common to glucose, amino acid, and organic acid secretagogues, involving flux through the pyruvate/isocitrate cycling pathway. Although the components of this pathway must remain intact for appropriate stimulus-secretion coupling, production of NADPH does not appear to be the universal second messenger signal generated by these reactions.

  1. Cytosolic peroxidases protect the lysosome of bloodstream African trypanosomes from iron-mediated membrane damage.

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    Corinna Hiller

    2014-04-01

    Full Text Available African trypanosomes express three virtually identical non-selenium glutathione peroxidase (Px-type enzymes which preferably detoxify lipid-derived hydroperoxides. As shown previously, bloodstream Trypanosoma brucei lacking the mitochondrial Px III display only a weak and transient proliferation defect whereas parasites that lack the cytosolic Px I and Px II undergo extremely fast lipid peroxidation and cell lysis. The phenotype can completely be rescued by supplementing the medium with the α-tocopherol derivative Trolox. The mechanism underlying the rapid cell death remained however elusive. Here we show that the lysosome is the origin of the cellular injury. Feeding the px I-II knockout parasites with Alexa Fluor-conjugated dextran or LysoTracker in the presence of Trolox yielded a discrete lysosomal staining. Yet upon withdrawal of the antioxidant, the signal became progressively spread over the whole cell body and was completely lost, respectively. T. brucei acquire iron by endocytosis of host transferrin. Supplementing the medium with iron or transferrin induced, whereas the iron chelator deferoxamine and apo-transferrin attenuated lysis of the px I-II knockout cells. Immunofluorescence microscopy with MitoTracker and antibodies against the lysosomal marker protein p67 revealed that disintegration of the lysosome precedes mitochondrial damage. In vivo experiments confirmed the negligible role of the mitochondrial peroxidase: Mice infected with px III knockout cells displayed only a slightly delayed disease development compared to wild-type parasites. Our data demonstrate that in bloodstream African trypanosomes, the lysosome, not the mitochondrion, is the primary site of oxidative damage and cytosolic trypanothione/tryparedoxin-dependent peroxidases protect the lysosome from iron-induced membrane peroxidation. This process appears to be closely linked to the high endocytic rate and distinct iron acquisition mechanisms of the infective

  2. Deep hypothermia-enhanced autophagy protects PC12 cells against oxygen glucose deprivation via a mitochondrial pathway.

    Science.gov (United States)

    Tang, Dang; Wang, Cheng; Gao, Yongjun; Pu, Jun; Long, Jiang; Xu, Wei

    2016-10-06

    Deep hypothermia is known for its organ-preservation properties, which is introduced into surgical operations on the brain and heart, providing both safety in stopping circulation as well as an attractive bloodless operative field. However, the molecular mechanisms have not been clearly identified. This study was undertaken to determine the influence of deep hypothermia on neural apoptosis and the potential mechanism of these effects in PC12 cells following oxygen-glucose deprivation. Deep hypothermia (18°C) was given to PC12 cells while the model of oxygen-glucose deprivation (OGD) induction for 1h. After 24h of reperfusion, the results showed that deep hypothermia decreased the neural apoptosis, and significantly suppressed overexpression of Bax, CytC, Caspase 3, Caspase 9 and cleaved PARP-1, and inhibited the reduction of Bcl-2 expression. While deep hypothermia increased the LC3II/LC3I and Beclin 1, an autophagy marker, which can be inhibited by 3-methyladenine (3-MA), indicating that deep hypothermia-enhanced autophagy ameliorated apoptotic cell death in PC12 cells subjected to OGD. Based on these findings we propose that deep hypothermia protects against neural apoptosis after the induction of OGD by attenuating the mitochondrial apoptosis pathway, moreover, the mechanism of these antiapoptosis effects is related to the enhancement of autophagy, which autophagy might provide a means of neuroprotection against OGD.

  3. Dietary polyphenols preconditioning protects 3T3-L1 preadipocytes from mitochondrial alterations induced by oxidative stress.

    Science.gov (United States)

    Baret, Pascal; Septembre-Malaterre, Axelle; Rigoulet, Michel; Lefebvre d'Hellencourt, Christian; Priault, Muriel; Gonthier, Marie-Paule; Devin, Anne

    2013-01-01

    Numerous studies indicate that an increase in reactive oxygen species (ROS) significantly affects white adipose tissue biology and leads to an inflammatory profile and insulin resistance, which could contribute to obesity-associated diabetes and cardiovascular diseases. Mitochondria play a key role in adipose tissue energy metabolism and constitute the main source of cellular ROS such as H(2)O(2). Polyphenols constitute the most abundant antioxidants provided by the human diet. Indeed, they are widely distributed in fruits, vegetables and some plant-derived beverages such as coffee and tea. Thus, the biological effects of dietary polyphenols that may increase the antioxidant capacity of the body against obesity-induced oxidative stress are of high interest. Here, we studied the capacity of polyphenols to modulate the impact of oxidative stress on the mitochondria of preadipocytes, which are important cells governing the adipose tissue development for energy homeostasis. Whereas H(2)O(2) treatment induces a proliferation arrest associated with an increase in mitochondrial content in 3T3-L1 preadipocytes, preconditioning with some major dietary polyphenols totally or partially protects the cells against oxidative stress consequences. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.

  4. Polyphenol-Rich Strawberry Extract Protects Human Dermal Fibroblasts against Hydrogen Peroxide Oxidative Damage and Improves Mitochondrial Functionality

    Directory of Open Access Journals (Sweden)

    Francesca Giampieri

    2014-06-01

    Full Text Available Strawberry bioactive compounds are widely known to be powerful antioxidants. In this study, the antioxidant and anti-aging activities of a polyphenol-rich strawberry extract were evaluated using human dermal fibroblasts exposed to H2O2. Firstly, the phenol and flavonoid contents of strawberry extract were studied, as well as the antioxidant capacity. HPLC-DAD analysis was performed to determine the vitamin C and β-carotene concentration, while HPLC-DAD/ESI-MS analysis was used for anthocyanin identification. Strawberry extract presented a high antioxidant capacity, and a relevant concentration of vitamins and phenolics. Pelargonidin- and cyanidin-glycosides were the most representative anthocyanin components of the fruits. Fibroblasts incubated with strawberry extract and stressed with H2O2 showed an increase in cell viability, a smaller intracellular amount of ROS, and a reduction of membrane lipid peroxidation and DNA damage. Strawberry extract was also able to improve mitochondrial functionality, increasing the basal respiration of mitochondria and to promote a regenerative capacity of cells after exposure to pro-oxidant stimuli. These findings confirm that strawberries possess antioxidant properties and provide new insights into the beneficial role of strawberry bioactive compounds on protecting skin from oxidative stress and aging.

  5. Erythropoietin-mediated tissue protection: reducing collateral damage from the primary injury response.

    Science.gov (United States)

    Brines, M; Cerami, A

    2008-11-01

    In its classic hormonal role, erythropoietin (EPO) is produced by the kidney and regulates the number of erythrocytes within the circulation to provide adequate tissue oxygenation. EPO also mediates other effects directed towards optimizing oxygen delivery to tissues, e.g. modulating regional blood flow and reducing blood loss by promoting thrombosis within damaged vessels. Over the past 15 years, many unexpected nonhaematopoietic functions of EPO have been identified. In these more recently appreciated nonhormonal roles, locally-produced EPO signals through a different receptor isoform and is a major molecular component of the injury response, in which it counteracts the effects of pro-inflammatory cytokines. Acutely, EPO prevents programmed cell death and reduces the development of secondary, pro-inflammatory cytokine-induced injury. Within a longer time frame, EPO provides trophic support to enable regeneration and healing. As the region immediately surrounding damage is typically relatively deficient in endogenous EPO, administration of recombinant EPO can provide increased tissue protection. However, effective use of EPO as therapy for tissue injury requires higher doses than for haematopoiesis, potentially triggering serious adverse effects. The identification of a tissue-protective receptor isoform has facilitated the engineering of nonhaematopoietic, tissue-protective EPO derivatives, e.g. carbamyl EPO, that avoid these complications. Recently, regions within the EPO molecule mediating tissue protection have been identified and this has enabled the development of potent tissue-protective peptides, including some mimicking EPO's tertiary structure but unrelated in primary sequence.

  6. The prion protein regulates glutamate-mediated Ca(2+) entry and mitochondrial Ca(2+) accumulation in neurons.

    Science.gov (United States)

    De Mario, Agnese; Peggion, Caterina; Massimino, Maria Lina; Viviani, Francesca; Castellani, Angela; Giacomello, Marta; Lim, Dmitry; Bertoli, Alessandro; Sorgato, Maria Catia

    2017-08-15

    The cellular prion protein (PrP(C)) whose conformational misfolding leads to the production of deadly prions, has a still-unclarified cellular function despite decades of intensive research. Following our recent finding that PrP(C) limits Ca(2+) entry via store-operated Ca(2+) channels in neurons, we investigated whether the protein could also control the activity of ionotropic glutamate receptors (iGluRs). To this end, we compared local Ca(2+) movements in primary cerebellar granule neurons and cortical neurons transduced with genetically encoded Ca(2+) probes and expressing, or not expressing, PrP(C) Our investigation demonstrated that PrP(C) downregulates Ca(2+) entry through each specific agonist-stimulated iGluR and after stimulation by glutamate. We found that, although PrP-knockout (KO) mitochondria were displaced from the plasma membrane, glutamate addition resulted in a higher mitochondrial Ca(2+) uptake in PrP-KO neurons than in their PrP(C)-expressing counterpart. This was because the increased Ca(2+) entry through iGluRs in PrP-KO neurons led to a parallel increase in Ca(2+)-induced Ca(2+) release via ryanodine receptor channels. These data thus suggest that PrP(C) takes part in the cell apparatus controlling Ca(2+) homeostasis, and that PrP(C) is involved in protecting neurons from toxic Ca(2+) overloads. © 2017. Published by The Company of Biologists Ltd.

  7. Casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhou; Mei-Fang Quan; Fei Liu; Su-Fang Zhou; Yong-Xiang Zhao; Yi Peng; Qi-Qi Mao; Xia Li; Ming-Wu Chen; Jing Su; Li Tian; Nai-Quan Mao; Ling-Zhi Long

    2013-01-01

    Objective: To assess if casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells. Methods: Human non-small-cell lung carcinoma cell lines H460, A549 and H157 were cultured in vitro. The cytotoxic activities were determined using MTT assay. The apoptotic cells death was examined by flow cytometry using PI staining and DNA agarose gel electrophoresis. The activities of caspase-3,-8 and -9 were measured via ELISA. Cellular fractionation was determined by flow cytometry to assess release of cytochrome c and the mitochondrial transmembrane potential. Bcl-2/Bcl-XL/XIAP/Bid/ DR5 and DR4 proteins were analyzed using western blot. Results: The concentrations required for a 50% decrease in cell growth (IC50) ranged from 1.8 to 3.2 μM. Casticin induced rapid apoptosis and triggered a series of effects associated with apoptosis by way of mitochondrial pathway, including the depolarization of the mitochondrial membrane, release of cytochrome c from mitochondria, activation of procaspase-9 and -3, and increase of DNA fragments. Moreover, the pan caspase inhibitor zVAD-FMK and the caspase-3 inhibitor zDEVD-FMK suppressed casticin-induced apoptosis. In addition, casticin induced XIAP and Bcl-XL down-regulation, Bax upregulation and Bid clearage. In H157 cell line, casticin increased expression of DR5 at protein levels but not affect the expression of DR4. The pretreatment with DR5/Fc chimera protein effectively attenuated casticin-induced apoptosis in H157 cells. No correlation was found between cell sensitivity to casticin and that to p53 status, suggesting that casticin induce a p53-independent apoptosis. Conclusions: Our results demonstrate that casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells.

  8. Autophagy Inhibition Enhances the Mitochondrial-Mediated Apoptosis Induced by Mangrove (Avicennia marina) Extract in Human Breast Cancer Cells

    KAUST Repository

    Esau, Luke

    2015-01-10

    Aims: Avicennia marina (AM) is a widely distributed mangrove plant that has been used in traditional medicine for centuries for the treatment of a number of diseases. The objective of the present study was to evaluate the leaf ethyl acetate extract of AM for its cytotoxic and apoptotic potential along with in-depth investigations of its mechanism of action in breast cancer MCF-7 cells. Study Design: The ethyl acetate extract of leaves and stems of AM was tested against estrogen positive breast cancer cell line MCF-7 using various assays. Place and Duration of Study: The study was carried out at King Abdullah University of Science and Technology, Thuwal, Saudi Arabia, from July 2013-June 2014. Methodology: Dose- and time-dependent growth inhibition of cancer cells was measured using MTT assay. The mechanisms of apoptosis induction were determined using various assays: phosphatidylserine exposure, caspase-3/7 activation, mitochondrial membrane potential disruption, reactive oxygen species (ROS) production, cell cycle analysis, autophagy, and protein expression using western blotting. The modulation of apoptotic genes (p53, Mdm2, NF-kB, Bad, Bax, Bcl-2 and Casp7) was also determined using real time PCR. Results: The AM extract inhibited breast cancer cell growth and induced apoptosis in a concentration dependent manner. We demonstrated a non-classical mode of apoptosis induction in MCF-7 cells by AM extract, where ROS production altered the mitochondrial membrane potential to induce apoptosis. Breast cancer cells treated with 200 µg/ml concentration of AM extract showed increased ROS production and disrupted MMP but no PARP-1 cleavage and a marked decrease in Caspase-7 protein levels (24 and 48 h) were detected. A significant amount of autophagy was also observed at the same concentration. However, treatment of MCF-7 cells with 200 µg/ml of AM extract along with the inhibition of autophagy by chloroquine, significantly increased the apoptosis from 20% to 45

  9. JNK1 protects against glucolipotoxicity-mediated beta-cell apoptosis

    DEFF Research Database (Denmark)

    Prause, Michala; Christensen, Dan Ploug; Billestrup, Nils

    2014-01-01

    INS1 cells showed increased apoptosis and cleaved caspase 9 and 3 compared to non-sense shRNA expressing control INS1 cells when exposed to palmitate and high glucose associated with increased CHOP expression, ROS formation and Puma mRNA expression. JNK2 shRNA expressing INS1 cells did not affect...... palmitate and high glucose induced apoptosis or ER stress markers, but increased Puma mRNA expression compared to non-sense shRNA expressing INS1 cells. Finally, JNK3 shRNA expressing INS1 cells did not induce apoptosis compared to non-sense shRNA expressing INS1 cells when exposed to palmitate and high...... glucose but showed increased caspase 9 and 3 cleavage associated with increased DP5 and Puma mRNA expression. These data suggest that JNK1 protects against palmitate and high glucose-induced β-cell apoptosis associated with reduced ER and mitochondrial stress....

  10. PGC-1α Mediated Peripheral Nerve Protection of Tongxinluo in STZ-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Xiaopei Cui

    2016-01-01

    Full Text Available Aim. To investigate the effect of Tongxinluo (Txl, a Chinese herbal compound, on diabetic peripheral neuropathy (DPN. Methods and Results. Diabetic rat model was established by peritoneal injection of streptozotocin (STZ. Txl ultrafine powder treatment for 16 weeks from the baseline significantly reversed the impairment of motor nerve conductive velocity (MNCV, mechanical hyperalgesia, and nerve structure. We further proved that Tongxinluo upregulates PGC-1α and its downstream factors including COX IV and SOD, which were involved in mitochondrial biogenesis. Conclusion. Our study indicates that the protective effect of Txl in diabetic neuropathy may be attributed to the induction of PGC-1α and its downstream targets. This finding may further illustrate the pleiotropic effect of the medicine.

  11. Sulforaphane Protects against High Cholesterol-Induced Mitochondrial Bioenergetics Impairments, Inflammation, and Oxidative Stress and Preserves Pancreatic β-Cells Function

    Directory of Open Access Journals (Sweden)

    Catalina Carrasco-Pozo

    2017-01-01

    Full Text Available Cholesterol plays an important role in inducing pancreatic β-cell dysfunction, leading to an impaired insulin secretory response to glucose. This study aimed to determine the protective effects of sulforaphane, a natural isothiocyanate Nrf2-inducer, against cholesterol-induced pancreatic β-cells dysfunction, through molecular and cellular mechanisms involving mitochondrial bioenergetics. Sulforaphane prevented cholesterol-induced alterations in the coupling efficiency of mitochondrial respiration, improving ATP turnover and spare capacity, and averted the impairment of the electron flow at complexes I, II, and IV. Sulforaphane also attenuated the cholesterol-induced activation of the NFκB pathway, normalizing the expression of pro- and anti-inflammatory cytokines. In addition, it also inhibited the decrease in sirtuin 1 expression and greatly increased Pgc-1α expression in Min6 cells. Sulforaphane increased the expression of antioxidant enzymes downstream of the Nrf2 pathway and prevented lipid peroxidation induced by cholesterol. The antioxidant and anti-inflammatory properties of sulforaphane and its ability to protect and improve mitochondrial bioenergetic function contribute to its protective action against cholesterol-induced pancreatic β-cell dysfunction. Our data provide a scientifically tested foundation upon which sulforaphane can be developed as nutraceutical to preserve β-cell function and eventually control hyperglycemia.

  12. Sulforaphane Protects against High Cholesterol-Induced Mitochondrial Bioenergetics Impairments, Inflammation, and Oxidative Stress and Preserves Pancreatic β-Cells Function.

    Science.gov (United States)

    Carrasco-Pozo, Catalina; Tan, Kah Ni; Gotteland, Martin; Borges, Karin

    2017-01-01

    Cholesterol plays an important role in inducing pancreatic β-cell dysfunction, leading to an impaired insulin secretory response to glucose. This study aimed to determine the protective effects of sulforaphane, a natural isothiocyanate Nrf2-inducer, against cholesterol-induced pancreatic β-cells dysfunction, through molecular and cellular mechanisms involving mitochondrial bioenergetics. Sulforaphane prevented cholesterol-induced alterations in the coupling efficiency of mitochondrial respiration, improving ATP turnover and spare capacity, and averted the impairment of the electron flow at complexes I, II, and IV. Sulforaphane also attenuated the cholesterol-induced activation of the NFκB pathway, normalizing the expression of pro- and anti-inflammatory cytokines. In addition, it also inhibited the decrease in sirtuin 1 expression and greatly increased Pgc-1α expression in Min6 cells. Sulforaphane increased the expression of antioxidant enzymes downstream of the Nrf2 pathway and prevented lipid peroxidation induced by cholesterol. The antioxidant and anti-inflammatory properties of sulforaphane and its ability to protect and improve mitochondrial bioenergetic function contribute to its protective action against cholesterol-induced pancreatic β-cell dysfunction. Our data provide a scientifically tested foundation upon which sulforaphane can be developed as nutraceutical to preserve β-cell function and eventually control hyperglycemia.

  13. A PGC-1α-Mediated Transcriptional Network Maintains Mitochondrial Redox and Bioenergetic Homeostasis against Doxorubicin-Induced Toxicity in Human Cardiomyocytes: Implementation of TT21C.

    Science.gov (United States)

    Yuan, Haitao; Zhang, Qiang; Guo, Jiabin; Zhang, Tingfen; Zhao, Jun; Li, Jin; White, Andrew; Carmichael, Paul L; Westmoreland, Carl; Peng, Shuangqing

    2016-04-01

    Chemical toxicity testing is fast moving in a direction that relies increasingly on cell-basedin vitroassays anchored on toxicity pathways according to the toxicity testing in the 21st century vision. Identifying points of departure (POD) via these assays and revealing their mechanistic underpinnings via computational modeling of the relevant pathways are critical and challenging steps. Here we used doxorubicin (DOX) as a prototype chemical to study mitochondrial toxicity in human AC16 cells. Mitochondrial toxicity has been linked to cardiovascular risk of DOX, which has limited its clinical use as an antitumor drug. Ourin vitrostudy revealed a well-defined POD concentration of DOX below which adaptive induction of proliferator-activated receptor-γ coactivator-1α (PGC-1α) -mediated mitochondrial genes, including NRF-1, MnSOD, UCP2, and COX1, concurred with negligible changes in mitochondrial superoxide and cytotoxicity. At higher DOX concentrations adversity became significant with elevated superoxide and suppressed ATP levels. A computational model was formulated to simulate the PGC-1α-mediated transcriptional network comprising multiple negative feedback loops that underlie redox and bioenergetics homeostasis in the mitochondrion. The model recapitulated the transition phase from adaptive to adverse responses, supporting the notion that saturated induction of PGC-1α-mediated gene network underpins POD. The model further predicts (follow-up experiments verified) that silencing PGC-1α compromises the adaptive function of the transcriptional network, leading to disruption of mitochondria and cytotoxicity at lower DOX concentrations. In summary, our study demonstrates that combining pathway-focusedin vitroassays and computational simulation of relevant biochemical network is synergistic for understanding dose-response behaviors in the low-dose region and identifying POD.

  14. Protective role of morin, a flavonoid, against high glucose induced oxidative stress mediated apoptosis in primary rat hepatocytes.

    Directory of Open Access Journals (Sweden)

    Radhika Kapoor

    Full Text Available Apoptosis is an early event of liver damage in diabetes and oxidative stress has been linked to accelerate the apoptosis in hepatocytes. Therefore, the compounds that can scavenge ROS may confer regulatory effects on high-glucose induced apoptosis. In the present study, primary rat hepatocytes were exposed to high concentration (40 mM of glucose. At this concentration decreased cell viability and enhanced ROS generation was observed. Depleted antioxidant status of hepatocytes under high glucose stress was also observed as evident from transcriptional level and activities of antioxidant enzymes. Further, mitochondrial depolarisation was accompanied by the loss of mitochondrial integrity and altered expression of Bax and Bcl-2. Increased translocation of apoptotic proteins like AIF (Apoptosis inducing factor & Endo-G (endonuclease-G from its resident place mitochondria to nucleus was also observed. Cyt-c residing in the inter-membrane space of mitochondria also translocated to cytoplasm. These apoptotic proteins initiated caspase activation, DNA fragmentation, chromatin condensation, increased apoptotic DNA content in glucose treated hepatocytes, suggesting mitochondria mediated apoptotic mode of cell death. Morin, a dietary flavonoid from Psidium guajava was effective in increasing the cell viability and decreasing the ROS level. It maintained mitochondrial integrity, inhibited release of apoptotic proteins from mitochondria, prevented DNA fragmentation, chromatin condensation and hypodiploid DNA upon exposure to high glucose. This study confirms the capacity of dietary flavonoid Morin in regulating apoptosis induced by high glucose via mitochondrial mediated pathway through intervention of oxidative stress.

  15. THE EU DIRECTIVE ON MEDIATION IN CIVIL AND COMMERCIAL MATTERS AND THE PRINCIPLE OF EFFECTIVE JUDICIAL PROTECTION

    Directory of Open Access Journals (Sweden)

    Antonio Maria MARZOCCO

    2012-11-01

    Full Text Available The essay concerns the implications of EU Directive 2008/52/EC regarding mediation in civil and commercial matters on the right of effective judicial protection. After having underlined the importance assumed in the European Union by alternative dispute resolution, the essay examines the stages that led European institutions to the adoption of the Directive on mediation in civil and commercial matters. The article addresses the aims and the scope of the Directive and subsequently focuses its attention on Directive dispositions regulating the “key aspects” of civil procedure. The essay emphasizes that the Directive, in substance, allows both optional mediation and compulsory mediation. However, compulsory mediation can contrast with the principle of effective judicial protection. Furthermore, the essay deals with the relationship between compulsory mediation and the principle of effective judicial protection, and identifies, examining a recent pronouncement of the EU Court of Justice, the needed requisites to be respected in order that such contrast does not occur.

  16. Analysis of Mitochondrial Proteins in the Surviving Myocardium after Ischemia Identifies Mitochondrial Pyruvate Carrier Expression as Possible Mediator of Tissue Viability.

    Science.gov (United States)

    Fernández-Caggiano, Mariana; Prysyazhna, Oleksandra; Barallobre-Barreiro, Javier; CalviñoSantos, Ramón; Aldama López, Guillermo; Generosa Crespo-Leiro, Maria; Eaton, Philip; Doménech, Nieves

    2016-01-01

    The endogenous mechanisms contributing to tissue survival following myocardial infarction are not fully understood. We investigated the alterations in the mitochondrial proteome after ischemia-reperfusion (I/R) and its possible implications on cell survival. Mitochondrial proteomic analysis of cardiac tissue from an in vivo porcine I/R model found that surviving tissue in the peri-infarct border zone showed increased expression of several proteins. Notably, these included subunits of the mitochondrial pyruvate carrier (MPC), namely MPC1 and MPC2. Western blot, immunohistochemistry, and mRNA analysis corroborated the elevated expression of MPC in the surviving tissue. Furthermore, MPC1 and MPC2 protein levels were found to be markedly elevated in the myocardium of ischemic cardiomyopathy patients. These findings led to the hypothesis that increased MPC expression is cardioprotective due to enhancement of mitochondrial pyruvate uptake in the energy-starved heart following I/R. To test this, isolated mouse hearts perfused with a modified Krebs buffer (containing glucose, pyruvate, and octanoate as metabolic substrates) were subjected to I/R with or without the MPC transport inhibitor UK5099. UK5099 increased myocardial infarction and attenuated post-ischemic recovery of left ventricular end-diastolic pressure. However, aerobically perfused control hearts that were exposed to UK5099 did not modulate contractile function, although pyruvate uptake was blocked as evidenced by increased cytosolic lactate and pyruvate levels. Our findings indicate that increased expression of MPC leads to enhanced uptake and utilization of pyruvate during I/R. We propose this as a putative endogenous mechanism that promotes myocardial survival to limit infarct size.

  17. miR-30 functions as an oncomiR in gastric cancer cells through regulation of P53-mediated mitochondrial apoptotic pathway.

    Science.gov (United States)

    Wang, Jianjun; Jiao, Yang; Cui, Lunmeng; Jiang, Lili

    2017-01-01

    The present study was designed to investigate the role of miR-30 in the development of Gastric cancer (GC). miR-30 expression was increased in GC tissues and cell lines. Downregulation of miR-30 inhibited cell proliferation and promoted apoptosis in HGC-27 cells. Upregulation of miR-30 enhanced the proliferation and inhibited apoptosis. P53 expression was decreased in GC tissues. P53 expression was correlated with miR-30 expression. Downregulation of miR-30 increased P53 expression. Knockdown of P53 inhibited miR-30-inhibitor-induced suppression of cell proliferation and increase of apoptosis. Downregulation of miR-30 increased ROS generation which was inhibited by shP53. miR-30 inhibitors induced a decrease in mitochondrial oxygen consumption, cytoplasmic release of cytochrome c, and activation of Caspase 3 and 9, activating mitochondrial apoptotic pathway. Downregulation of P53 and N-acetyl-cysteine suppressed miR-30 inhibitors-activated mitochondrial dysfunction and apoptotic events. In conclusion, we identified that miR-30 functioned as a potential oncomiR through P53/ROS-mediated regulation of mitochondrial apoptotic pathway.

  18. Fucoidan Derived from Undaria pinnatifida Induces Apoptosis in Human Hepatocellular Carcinoma SMMC-7721 Cells via the ROS-Mediated Mitochondrial Pathway

    Directory of Open Access Journals (Sweden)

    Lin Hou

    2013-06-01

    Full Text Available Fucoidans, fucose-enriched sulfated polysaccharides isolated from brown algae and marine invertebrates, have been shown to exert anticancer activity in several types of human cancer, including leukemia and breast cancer and in lung adenocarcinoma cells. In the present study, the anticancer activity of the fucoidan extracted from the brown seaweed Undaria pinnatifida was investigated in human hepatocellular carcinoma SMMC-7721 cells, and the underlying mechanisms of action were investigated. SMMC-7721 cells exposed to fucoidan displayed growth inhibition and several typical features of apoptotic cells, such as chromatin condensation and marginalization, a decrease in the number of mitochondria, and in mitochondrial swelling and vacuolation. Fucoidan-induced cell death was associated with depletion of reduced glutathione (GSH, accumulation of high intracellular levels of reactive oxygen species (ROS, and accompanied by damage to the mitochondrial ultrastructure, depolarization of the mitochondrial membrane potential (MMP, Δψm and caspase activation. Moreover, fucoidan led to altered expression of factors related to apoptosis, including downregulating Livin and XIAP mRNA, which are members of the inhibitor of apoptotic protein (IAP family, and increased the Bax-to-Bcl-2 ratio. These findings suggest that fucoidan isolated from U. pinnatifida induced apoptosis in SMMC-7721 cells via the ROS-mediated mitochondrial pathway.

  19. Protective coupling of mitochondrial function and protein synthesis via the eIF2α kinase GCN-2.

    Directory of Open Access Journals (Sweden)

    Brooke M Baker

    Full Text Available Cells respond to defects in mitochondrial function by activating signaling pathways that restore homeostasis. The mitochondrial peptide exporter HAF-1 and the bZip transcription factor ATFS-1 represent one stress response pathway that regulates the transcription of mitochondrial chaperone genes during mitochondrial dysfunction. Here, we report that GCN-2, an eIF2α kinase that modulates cytosolic protein synthesis, functions in a complementary pathway to that of HAF-1 and ATFS-1. During mitochondrial dysfunction, GCN-2-dependent eIF2α phosphorylation is required for development as well as the lifespan extension observed in Caenorhabditis elegans. Reactive oxygen species (ROS generated from dysfunctional mitochondria are required for GCN-2-dependent eIF2α phosphorylation but not ATFS-1 activation. Simultaneous deletion of ATFS-1 and GCN-2 compounds the developmental defects associated with mitochondrial stress, while stressed animals lacking GCN-2 display a greater dependence on ATFS-1 and stronger induction of mitochondrial chaperone genes. These findings are consistent with translational control and stress-dependent chaperone induction acting in complementary arms of the UPR(mt.

  20. Host Nonresponsiveness Does not Interfere With Vaccine-Mediated Protection Against Gastric Helicobacter Infection.

    Science.gov (United States)

    Harbour, Stacey N; Mitchell, Hazel M; Sutton, Philip

    2015-06-01

    Helicobacter pylori pathogenesis results from the inflammation induced by chronic infection. CBA mice are nonresponsive to gastric Helicobacter infection, providing a useful model for examining host regulation of Helicobacter-induced gastritis. We examined whether gastric Helicobacter nonresponsiveness impacts upon vaccine efficacy and whether immune-mediated protection could occur in the absence of inflammation. Mice were vaccinated prior to challenge with Helicobacter felis or H. pylori. Gastritis and H. felis colonization was evaluated histologically. H. pylori colonization was quantified by colony-forming assay. Immunizations protected CBA mice against challenge with either H. felis or H. pylori. Protection against H. felis was marked by a loss of nonresponsiveness and development of an atrophic gastritis with mucus metaplasia. However, vaccine-induced protection against H. pylori was only associated with cell infiltration into the gastric mucosa. Nonresponsiveness to gastric Helicobacter infection did not interfere with vaccination-induced protection. Vaccine-induced protective immunity against H. pylori was linked with the induction of cellular infiltration, but importantly not atrophic gastritis. © 2015 John Wiley & Sons Ltd.

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

    Science.gov (United States)

    Boscolo, A; Starr, JA; Sanchez; Lunardi, N; DiGruccio, MR; Ori, C; Erisir, A; Trimmer, P; Bennett, J; Jevtovic-Todorovic

    2011-01-01

    Early exposure to general anesthesia (GA) causes developmental neuroapoptosis in the mammalian brain and long-term cognitive impairment. Recent evidence suggests that GA also causes functional and morphological impairment of the immature neuronal mitochondria. Injured mitochondria could be a significant source of reactive oxygen species (ROS), which, if not scavenged in timely fashion, may cause excessive lipid peroxidation and damage of cellular membranes. We examined whether early exposure to GA results in ROS upregulation and whether mitochondrial protection and ROS scavenging prevent GA-induced pathomorphological and behavioral impairments. We exposed 7-day-old rats to GA with or without either EUK-134, a synthetic ROS scavenger, or R(+) pramipexole (PPX), a synthetic aminobenzothiazol derivative that restores mitochondrial integrity. We found that GA causes extensive ROS upregulation and lipid peroxidation, as well as mitochondrial injury and neuronal loss in the subiculum. As compared to rats given only GA, those also given PPX or EUK-134 had significantly downregulated lipid peroxidation, preserved mitochondrial integrity, and significantly less neuronal loss. The subiculum is highly intertwined with the hippocampal CA1 region, anterior thalamic nuclei, and both entorhinal and cingulate cortices; hence, it is important in cognitive development. We found that PPX or EUK-134 co-treatment completely prevented GA-induced cognitive impairment. Because mitochondria are vulnerable to GA-induced developmental neurotoxicity, they could be an important therapeutic target for adjuvant therapy aimed at improving the safety of commonly used GAs. PMID:22198380

  2. Protective effects of compound FLZ, a novel synthetic analogue of squamosamide, on β-amyloid-induced rat brain mitochondrial dysfunction in vitro

    Institute of Scientific and Technical Information of China (English)

    Fang FANG; Geng-tao LIU

    2009-01-01

    Aim: The aim of the present study was to assess the effects of N-[2-(4-hydroxyphenyl)ethyl]-2-(2,5-dimethoxyphenyl)-3-(3-methoxy-4-hydroxyphenyl) acrylamide (compound FLZ), a novel synthetic analogue of squamosamide, on the dysfunction of rat brain mitochondria induced by Aβ25-35 in vitro.Methods: Isolated rat brain mitochondria were incubated with aged Aβ25-35 for 30 min in the presence and absence of FLZ (1-100 μmol/L). The activities of key mitochondrial enzymes, the production of hydrogen peroxide (H2O2) and superoxide anion (O.-2), and the levels of glutathione (GSH) in mitochondria were examined. Mitochondrial swelling and the release of cytochrome c from mitochondria were assessed by biochemical and Western blot methods, respectively.Results: Incubation of mitochondria with aged Aβ25-35 inhibited the activities of α-ketoglutarate dehydrogenase (α-KGDH),pyruvate dehydrogenase (PDH) and respiratory chain complex IV. It also resulted in increased H2O2 and O.-2 production,and decreased the GSH level in mitochondria. Furthermore, it induced mitochondrial swelling and cytochrome c release from the mitochondria. The addition of FLZ (100 μmol/L) prior to treatment with Aβ25-35 significantly prevented these toxic effects of Aβ25-35 on the mitochondria.Conclusion: FLZ has a protective effect against Aβ25-35-induced mitochondrial dysfunction in vitro.

  3. Hexarelin Protects Rodent Pancreatic Β-Cells Function from Cytotoxic Effects of Streptozotocin Involving Mitochondrial Signalling Pathways In Vivo and In Vitro.

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    Full Text Available Mitochondrial functions are crucial for pancreatic β-cell survival and glucose-induced insulin secretion. Hexarelin (Hex is a synthetic small peptide ghrelin analogue, which has been shown to protect cardiomyocytes from the ischemia-reperfusion process. In this study, we used in vitro and in vivo models of streptozotocin (STZ-induced β-cell damage to study the protective effect of Hex and the associated mechanisms. We found that STZ produced a cytotoxic effect in a dose- and time-dependent manner in MIN6 cells (a mouse β-cell line. Hex (1.0 μM decreased the STZ-induced damage in β-cells. Rhodamine 123 assay and superoxide DHE production assay revealed that Hex ameliorated STZ-induced mitochondrial damage and excessive superoxide activity in β-cells. In addition, Hex significantly reduced STZ-induced expression of cleaved Caspases-3, Caspases-9 and the ratio of pro-apoptotic protein Bax to anti-apoptotic protein Bcl-2 in MIN6 cells. We further examined the in vivo effect of Hex in a rat model of type 1 diabetes induced by STZ injection. Hex ameliorated STZ-induced decrease in plasma insulin and protected the structure of islets from STZ-induced disruption. Hex also ameliorated STZ-induced expression of cleaved Caspase-9 and the Bax in β-cells. In conclusion, our data indicate that Hex is able to protects β-cell mass from STZ-caused cytotoxic effects involving mitochondrial pathways in vitro and in vivo. Hex may serve as a potential protective agent for the management of diabetes.

  4. Sustainable Redox Mediation for Lithium-Oxygen Batteries by a Composite Protective Layer on the Lithium-Metal Anode.

    Science.gov (United States)

    Lee, Dong Jin; Lee, Hongkyung; Kim, Yun-Jung; Park, Jung-Ki; Kim, Hee-Tak

    2016-02-03

    A synergic combination of a soluble -redox mediator and a protected Li metal -electrode to prevent the self-discharge of the redox mediator is realized by -exploiting a 2,2,6,6-tetramethylpiperidinyl 1-oxyl (TEMPO) redox mediator and an Al2 O3 /PVdF-HFP composite -protective layer (CPL). Stabilization of Li metal by simple CPL coating is effective at -suppressing the chemical reduction of the oxidized TEMPO and opens up the possibility of sustainable redox mediation for robust cycling of Li-O2 batteries.

  5. Green tea polyphenols induce cell death in breast cancer MCF-7 cells through induction of cell cycle arrest and mitochondrial-mediated apoptosis*

    Science.gov (United States)

    Liu, Shu-min; Ou, Shi-yi; Huang, Hui-hua

    2017-01-01

    In order to study the molecular mechanisms of green tea polyphenols (GTPs) in treatment or prevention of breast cancer, the cytotoxic effects of GTPs on five human cell lines (MCF-7, A549, Hela, PC3, and HepG2 cells) were determined and the antitumor mechanisms of GTPs in MCF-7 cells were analyzed. The results showed that GTPs exhibited a broad spectrum of inhibition against the detected cancer cell lines, particularly the MCF-7 cells. Studies on the mechanisms revealed that the main modes of cell death induced by GTPs were cell cycle arrest and mitochondrial-mediated apoptosis. Flow cytometric analysis showed that GTPs mediated cell cycle arrest at both G1/M and G2/M transitions. GTP dose dependently led to apoptosis of MCF-7 cells via the mitochondrial pathways, as evidenced by induction of chromatin condensation, reduction of mitochondrial membrane potential (ΔΨ m), improvement in the generation of reactive oxygen species (ROS), induction of DNA fragmentation, and activations of caspase-3 and caspase-9 in the present paper. PMID:28124838

  6. Ginsenoside Rb1 Protects Neonatal Rat Cardiomyocytes from Hypoxia/Ischemia Induced Apoptosis and Inhibits Activation of the Mitochondrial Apoptotic Pathway

    Directory of Open Access Journals (Sweden)

    Xu Yan

    2014-01-01

    Full Text Available Aim. To investigate the effect of Ginsenoside Rb1 (GS-Rb1 on hypoxia/ischemia (H/I injury in cardiomyocytes in vitro and the mitochondrial apoptotic pathway mediated mechanism. Methods. Neonatal rat cardiomyocytes (NRCMs for the H/I groups were kept in DMEM without glucose and serum, and were placed into a hypoxic jar for 24 h. GS-Rb1 at concentrations from 2.5 to 40 µM was given during hypoxic period for 24 h. NRCMs injury was determined by MTT and lactate dehydrogenase (LDH leakage assay. Cell apoptosis, ROS accumulation, and mitochondrial membrane potential (MMP were assessed by flow cytometry. Cytosolic translocation of mitochondrial cytochrome c and Bcl-2 family proteins were determined by Western blot. Caspase-3 and caspase-9 activities were determined by the assay kit. Results. GS-Rb1 significantly reduced cell death and LDH leakage induced by H/I. It also reduced H/I induced NRCMs apoptosis induced by H/I, in accordance with a minimal reactive oxygen species (ROS burst. Moreover, GS-Rb1 markedly decreased the translocation of cytochrome c from the mitochondria to the cytosol, increased the Bcl-2/ Bax ratio, and preserved mitochondrial transmembrane potential (ΔΨm. Its administration also inhibited activities of caspase-9 and caspase-3. Conclusion. Administration of GS-Rb1 during H/I in vitro is involved in cardioprotection by inhibiting apoptosis, which may be due to inhibition of the mitochondrial apoptotic pathway.

  7. Molecular Mechanisms Responsible for Neuron-Derived Conditioned Medium (NCM)-Mediated Protection of Ischemic Brain.

    Science.gov (United States)

    Lin, Chi-Hsin; Wang, Chen-Hsuan; Hsu, Shih-Lan; Liao, Li-Ya; Lin, Ting-An; Hsueh, Chi-Mei

    2016-01-01

    The protective value of neuron-derived conditioned medium (NCM) in cerebral ischemia and the underlying mechanism(s) responsible for NCM-mediated brain protection against cerebral ischemia were investigated in the study. NCM was first collected from the neuronal culture growing under the in vitro ischemic condition (glucose-, oxygen- and serum-deprivation or GOSD) for 2, 4 or 6 h. Through the focal cerebral ischemia (bilateral CCAO/unilateral MCAO) animal model, we discovered that ischemia/reperfusion (I/R)-induced brain infarction was significantly reduced by NCM, given directly into the cistern magna at the end of 90 min of CCAO/MCAO. Immunoblocking and chemical blocking strategies were applied in the in vitro ischemic studies to show that NCM supplement could protect microglia, astrocytes and neurons from GOSD-induced cell death, in a growth factor (TGFβ1, NT-3 and GDNF) and p-ERK dependent manner. Brain injection with TGFβ1, NT3, GDNF and ERK agonist (DADS) alone or in combination, therefore also significantly decreased the infarct volume of ischemic brain. Moreover, NCM could inhibit ROS but stimulate IL-1β release from GOSD-treated microglia and limit the infiltration of IL-β-positive microglia into the core area of ischemic brain, revealing the anti-oxidant and anti-inflammatory activities of NCM. In overall, NCM-mediated brain protection against cerebral ischemia has been demonstrated for the first time in S.D. rats, due to its anti-apoptotic, anti-oxidant and potentially anti-glutamate activities (NCM-induced IL-1β can inhibit the glutamate-mediated neurotoxicity) and restriction upon the infiltration of inflammatory microglia into the core area of ischemic brain. The therapeutic potentials of NCM, TGFβ1, GDNF, NT-3 and DADS in the control of cerebral ischemia in human therefore have been suggested and require further investigation.

  8. Hypoxia mediates mitochondrial biogenesis in hepatocellular carcinoma to promote tumor growth through HMGB1 and TLR9 interaction.

    Science.gov (United States)

    Tohme, Samer; Yazdani, Hamza O; Liu, Yao; Loughran, Patricia; van der Windt, Dirk J; Huang, Hai; Simmons, Richard L; Shiva, Sruti; Tai, Sheng; Tsung, Allan

    2017-07-01

    The ability of cancer cells to survive and grow under hypoxic conditions has been known for decades, but the mechanisms remain poorly understood. Under certain conditions, cancer cells undergo changes in their bioenergetic profile to favor mitochondrial respiration by activating the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) and up-regulating mitochondrial biogenesis. In this study, we hypothesized that augmented mitochondrial biogenesis plays a critical role for cancer cells to survive hypoxia. Consistent with this hypothesis, both hypoxic human hepatocellular carcinoma (HCC) tumors and HCC cell lines subjected to hypoxia increase mitochondrial biogenesis. Silencing of PGC-1α in hypoxic HCC cell lines halts their proliferation. Mechanistic investigations in vitro indicated that intracellular high mobility group box 1 (HMGB1) protein, a nuclear protein overexpressed in HCC, is essential for the process. Silencing of HMGB1 in hypoxic HCC cell lines resulted in a significant decrease in PGC-1α activation and mitochondrial biogenesis. Without HMGB1, hypoxic HCC cells had significantly reduced adenosine triphosphate production, decreased cellular proliferation, and increased apoptosis. In a diethylnitrosamine-induced murine model of HCC, genetic blocking of HMGB1 in hypoxic tumors resulted in a significant decrease in tumor growth. Tumors lacking HMGB1 had a significant reduction in mitochondrial biogenesis and a significant increase in mitochondrial dysfunction. Further in vitro mechanistic experiments indicated that during hypoxia HMGB1 translocates from the nucleus to the cytoplasm and binds to cytoplasmic Toll-like receptor-9. This binding leads to activation of p38 and subsequent phosphorylation of PGC-1α, with resultant up-regulation of mitochondrial biogenesis. Taken together, our findings suggest that during hypoxia HMGB1 up-regulates mitochondrial biogenesis in HCC cancer cells, promoting tumor survival and proliferation

  9. Overexpression of DNA ligase III in mitochondria protects cells against oxidative stress and improves mitochondrial DNA base excision repair

    DEFF Research Database (Denmark)

    Akbari, Mansour; Keijzers, Guido; Maynard, Scott

    2014-01-01

    slower than the preceding mitochondrial BER steps. Overexpression of DNA ligase III in mitochondria improved the rate of overall BER, increased cell survival after menadione induced oxidative stress and reduced autophagy following the inhibition of the mitochondrial electron transport chain complex I...... by rotenone. Our results suggest that the amount of DNA ligase III in mitochondria may be critical for cell survival following prolonged oxidative stress, and demonstrate a functional link between mitochondrial DNA damage and repair, cell survival upon oxidative stress, and removal of dysfunctional......Base excision repair (BER) is the most prominent DNA repair pathway in human mitochondria. BER also results in a temporary generation of AP-sites, single-strand breaks and nucleotide gaps. Thus, incomplete BER can result in the generation of DNA repair intermediates that can disrupt mitochondrial...

  10. Hepato-protective effects of six schisandra lignans on acetaminophen-induced liver injury are partially associated with the inhibition of CYP-mediated bioactivation.

    Science.gov (United States)

    Jiang, Yiming; Fan, Xiaomei; Wang, Ying; Tan, Huasen; Chen, Pan; Zeng, Hang; Huang, Min; Bi, Huichang

    2015-04-25

    Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra fructus is widely-used traditional Chinese medicine which possesses hepato-protective potential. Schisandrin A (SinA), Schisandrin B (SinB), Schisandrin C (SinC), Schisandrol A (SolA), Schisandrol B (SolB), and Schisantherin A (SthA) are the major bioactive lignans. Most recently, we found SolB exerts significant hepato-protection against APAP-induced liver injury. In this study, the protective effects of the other five schisandra lignans against APAP-induced acute hepatotoxicity in mice were investigated and compared with that of SolB. The results of morphological and biochemical assessment clearly demonstrated significant protective effects of SinA, SinB, SinC, SolA, SolB, and SthA against APAP-induced liver injury. Among these schisandra lignans, SinC and SolB exerted the strongest hepato-protective effects against APAP-induced hepatotoxicity. Six lignans pretreatment before APAP dosing could prevent the depletions of total liver glutathione (GSH) and mitochondrial GSH caused by APAP. Additionally, the lignans treatment inhibited the enzymatic activities of three CYP450 isoforms (CYP2E1, CYP1A2, and CYP3A11) related to APAP bioactivation, and further decreased the formation of APAP toxic intermediate N-acetyl-p-benzoquinone imine (NAPQI) in mouse microsomal incubation system. This study demonstrated that SinA, SinB, SinC, SolA, SolB and SthA exhibited significant protective actions toward APAP-induced liver injury, which was partially associated with the inhibition of CYP-mediated APAP bioactivation.

  11. Mitochondrial Porin Isoform AtVDAC1 Regulates the Competence of Arabidopsis thaliana to Agrobacterium-Mediated Genetic Transformation

    Science.gov (United States)

    Kwon, Tackmin

    2016-01-01

    The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background. Genetic complementation of Arabidopsis vdac1 mutants and yeast porin1-deficient strain with members of the AtVDAC gene family revealed that AtVDAC1 is required for Agrobacterium-mediated transformation, and there is weak functional redundancy between AtVDAC1 and AtVDAC3, which is independent of porin activity. Furthermore, atvdac1 mutants were deficient in transient and stable transformation by Agrobacterium, suggesting that AtVDAC1 is involved in the early stages of Agrobacterium infection prior to transferred-DNA (T-DNA) integration. Transgenic plants overexpressing AtVDAC1 not only complemented the phenotypes of the atvdac1 mutant, but also showed high efficiency of transient T-DNA gene expression; however, the efficiency of stable transformation was not affected. Moreover, the effect of phytohormone treatment on competence to Agrobacterium was compromised in atvdac1 mutants. These data indicate that AtVDAC1 regulates the competence of Arabidopsis to Agrobacterium infection. PMID:27643450

  12. Role of Fc in Antibody-Mediated Protection from Ricin Toxin

    Directory of Open Access Journals (Sweden)

    Seth. H. Pincus

    2014-05-01

    Full Text Available We have studied the role of the antibody (Ab Fc region in mediating protection from ricin toxicity. We compared the in vitro and in vivo effects of intact Ig and of Fab fragments derived from two different neutralizing Ab preparations, one monoclonal, the other polyclonal. Consistent results were obtained from each, showing little difference between Ig and Fab in terms of antigen binding and in vitro neutralization, but with relatively large differences in protection of animals. We also studied whether importing Ab into the cell by Fc receptors enhanced the intracellular neutralization of ricin toxin. We found that the imported Ab was found in the ER and Golgi, a compartment traversed by ricin, as it traffics through the cell, but intracellular Ab did not contribute to the neutralization of ricin. These results indicate that the Fc region of antibody is important for in vivo protection, although the mechanism of enhanced protection by intact Ig does not appear to operate at the single cell level. When using xenogeneic antibodies, the diminished immunogenicity of Fab/F(ab’2 preparations should be balanced against possible loss of protective efficacy.

  13. Ac-cel, a novel antioxidant, protects against hydrogen peroxide-induced injury in PC12 cells via attenuation of mitochondrial dysfunction.

    Science.gov (United States)

    Guo, Xianjun; Chen, Yuting; Liu, Qunfang; Wu, Jian; Wang, Luoyi; Tang, Xican; Zhao, Weimin; Zhang, Haiyan

    2013-07-01

    Oxidative stress has been implicated in pathophysiology of many neurodegenerative diseases (ND) and increased oxidative stress is closely associated with mitochondrial dysfunction. As a result, looking for potent antioxidants, especially those targeting mitochondria, has become an attractive strategy in ND therapy. In this study, we explored protective effects and potential mechanism of Ac-cel, a novel compound, against hydrogen peroxide (H(2)O(2))-induced injury in PC12 cells. Pretreatment of PC12 cells with Ac-cel prior to 24 h of H(2)O(2) exposure markedly attenuated cytotoxicity induced by H(2)O(2) as evidenced by morphological changes and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Ac-cel also exhibited potent antiapoptotic effect demonstrated by results of annexin V and PI staining. The above beneficial effects of Ac-cel were accompanied by improved mitochondrial function, reduced caspase-3 cleavage as well as upregulated ratio of Bcl-2/Bax protein expression. Moreover, Ac-cel pretreatment markedly reversed intracellular reactive oxygen species (ROS) accumulation following 30 min of H(2)O(2) exposure in PC12 cells. Further, subcellular investigation indicated that Ac-cel significantly reduced production of mitochondrial ROS in isolated rat cortical mitochondria. Taken together, the present study, for the first time, reports that Ac-cel pretreatment inhibits H(2)O(2)-stimulated early accumulation of intracellular ROS possibly via reducing mitochondrial ROS production directly and leads to subsequent preservation of mitochondrial function. These results indicate that Ac-cel is a potential drug candidate for treatment of oxidative stress-associated ND.

  14. Troxerutin protects the mouse liver against oxidative stress-mediated injury induced by D-galactose.

    Science.gov (United States)

    Zhang, Zi-feng; Fan, Shao-hua; Zheng, Yuan-lin; Lu, Jun; Wu, Dong-mei; Shan, Qun; Hu, Bin

    2009-09-01

    Troxerutin, a trihydroxyethylated derivative of rutin, has been well-demonstrated to exert hepatoprotective properties. In the present study, we attempted to explore whether the antioxidant and anti-inflammatory mechanisms were involved in troxerutin-mediated protection from D-gal-induced liver injury. The effects of troxerutin on liver lipid peroxidation, antioxidant enzymatic activities, and the expression of inflammatory mediator were investigated in D-gal-treated mice. The results showed that troxerutin largely attenuated the D-gal-induced TBARS content increase and also markedly renewed the activities of Cu, Zn-SOD, CAT, and GPx in the livers of D-gal-treated mice. Furthermore, troxerutin inhibited the upregulation of the expression of NF-kappaB p65, iNOS, and COX-2 induced by D-gal. D-Gal-induced tissue architecture changes and serum ALT and AST increases were effectively suppressed by troxerutin. In conclusion, these results suggested that troxerutin could protect the mouse liver from D-gal-induced injury by attenuating lipid peroxidation, renewing the activities of antioxidant enzymes and suppressing inflammatory response. This study provided novel insights into the mechanisms of troxerutin in the protection of the liver.

  15. Protective effects of phyllanthus emblica leaf extract on sodium arsenite-mediated adverse effects in mice.

    Science.gov (United States)

    Sayed, Sadia; Ahsan, Nazmul; Kato, Masashi; Ohgami, Nobutaka; Rashid, Abdur; Akhand, Anwarul Azim

    2015-02-01

    Groundwater contamination of arsenic is the major cause of a serious health hazard in Bangladesh. No specific treatment is yet available to manage the large number of individuals exposed to arsenic. In this study, we evaluated the protective effects of Phyllanthus emblica (Indian gooseberry or Amla) leaf extract (PLE) on arsenic-mediated toxicity in experimental mice. Male Swiss albino mice were divided into three different groups (n=6/group). 'Control' mice received arsenic free water together with normal feed. Mice in the remaining two groups designated 'SA' and 'SA+PLE' were exposed to sodium arsenite (SA, 10 µg/g body weight/day) through drinking water in addition to receiving normal feed and PLE-supplemented feed, respectively. The weight gain of SA-exposed mice was decreased compared with the controls; however, this decrease in body weight gain was prevented when the feed was supplemented with PLE. A secondary effect of arsenic was enlargement of the liver, kidney and spleen of SA-group mice. Deposition of arsenic in those organs was demonstrated by ICP-MS. When PLE was supplemented in the feed the enlargement of the organs was minimized; however, the deposition of arsenic was not significantly reduced. These results indicated that PLE may not block arsenic deposition in tissue directly but rather may play a protective role to reduce arsenic-induced toxicity. Therefore, co-administration of PLE in arsenic-exposed animals might have a future therapeutic application for protecting against arsenic-mediated toxicity.

  16. The Small Interfering RNA Pathway Is Not Essential for Wolbachia-Mediated Antiviral Protection in Drosophila melanogaster

    OpenAIRE

    Lauren M Hedges; Yamada, Ryuichi; O'Neill, Scott L; Karyn N. Johnson

    2012-01-01

    Wolbachia pipientis delays RNA virus-induced mortality in Drosophila spp. We investigated whether Wolbachia-mediated protection was dependent on the small interfering RNA (siRNA) pathway, a key antiviral defense. Compared to Wolbachia-free flies, virus-induced mortality was delayed in Wolbachia-infected flies with loss-of-function of siRNA pathway components, indicating that Wolbachia-mediated protection functions in the absence of the canonical siRNA pathway.

  17. Role of Mitochondrial Enzymes and Sarcoplasmic ATPase in Cardioprotection Mediated by Aqueous Extract of Desmodium gangeticum (L) DC Root on Ischemic Reperfusion Injury.

    Science.gov (United States)

    Kurian, G A; Paddikkala, J

    2010-11-01

    The present study investigate the protective effect of aqueous root extract of Desmodium gangeticum in preserving mitochondrial and sarcoplasmic ATPase during ischemia reperfusion injury. The isolated rat hearts in both drug and control group were subjected to warm ischemia (37°), followed by reperfusion with the Langendorff perfusion system. The aqueous root extract of Desmodium gangeticum (L) at a dose of 50 mg/kg body weight was found to be effective in the rat heart for the management of ischemic reperfusion injury. Physiological parameters were significantly (PDesmodium gangeticum treated rat heart. These results suggest that Desmodium gangeticum aqueous root extract can preserve the mitochondrial and sarcoplasmic ATPase in the myocardium, resulting in the improvement of cardiac function after ischemia reperfusion injury.

  18. Mitochondrial dysfunction in the APP/PSEN1 mouse model of Alzheimer's disease and a novel protective role for ascorbate.

    Science.gov (United States)

    Dixit, Shilpy; Fessel, Joshua P; Harrison, Fiona E

    2017-08-31

    Mitochondrial dysfunction is elevated in very early stages of Alzheimer's disease and exacerbates oxidative stress, which contributes to disease pathology. Mitochondria were isolated from 4-month-old wild-type mice, transgenic mice carrying the APPSWE and PSEN1dE9 mutations, mice with decreased brain and mitochondrial ascorbate (vitamin C) via heterozygous knockout of the sodium dependent vitamin C transporter (SVCT2(+/-)) and transgenic APP/PSEN1 mice with heterozygous SVCT2 expression. Mitochondrial isolates from SVCT2(+/-) mice were observed to consume less oxygen using high-resolution respirometry, and also exhibited decreased mitochondrial membrane potential compared to wild type isolates. Conversely, isolates from young (4 months) APP/PSEN1 mice consumed more oxygen, and exhibited an increase in mitochondrial membrane potential, but had a significantly lower ATP/ADP ratio compared to wild type isolates. Greater levels of reactive oxygen species were also produced in mitochondria isolated from both APP/PSEN1 and SVCT2(+/-) mice compared to wild type isolates. Acute administration of ascorbate to mitochondria isolated from wild-type mice increased oxygen consumption compared with untreated mitochondria suggesting ascorbate may support energy production. This study suggests that both presence of amyloid and ascorbate deficiency can contribute to mitochondrial dysfunction, even at an early, prodromal stage of Alzheimer's disease, although occurring via different pathways. Ascorbate may, therefore, provide a useful preventative strategy against neurodegenerative disease, particularly in populations most at risk for Alzheimer's disease in which stores are often depleted through mitochondrial dysfunction and elevated oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Curcumin Attenuates Gentamicin-Induced Kidney Mitochondrial Alterations: Possible Role of a Mitochondrial Biogenesis Mechanism

    Directory of Open Access Journals (Sweden)

    Mario Negrette-Guzmán

    2015-01-01

    Full Text Available It has been shown that curcumin (CUR, a polyphenol derived from Curcuma longa, exerts a protective effect against gentamicin- (GM- induced nephrotoxicity in rats, associated with a preservation of the antioxidant status. Although mitochondrial dysfunction is a hallmark in the GM-induced renal injury, the role of CUR in mitochondrial protection has not been studied. In this work, LLC-PK1 cells were preincubated 24 h with CUR and then coincubated 48 h with CUR and 8 mM GM. Treatment with CUR attenuated GM-induced drop in cell viability and led to an increase in nuclear factor (erythroid-2-related factor 2 (Nrf2 nuclear accumulation and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α cell expression attenuating GM-induced losses in these proteins. In vivo, Wistar rats were injected subcutaneously with GM (75 mg/Kg/12 h during 7 days to develop kidney mitochondrial alterations. CUR (400 mg/Kg/day was administered orally 5 days before and during the GM exposure. The GM-induced mitochondrial alterations in ultrastructure and bioenergetics as well as decrease in activities of respiratory complexes I and IV and induction of calcium-dependent permeability transition were mostly attenuated by CUR. Protection of CUR against GM-induced nephrotoxicity could be in part mediated by maintenance of mitochondrial functions and biogenesis with some participation of the nuclear factor Nrf2.

  20. Curcumin Attenuates Gentamicin-Induced Kidney Mitochondrial Alterations: Possible Role of a Mitochondrial Biogenesis Mechanism.

    Science.gov (United States)

    Negrette-Guzmán, Mario; García-Niño, Wylly Ramsés; Tapia, Edilia; Zazueta, Cecilia; Huerta-Yepez, Sara; León-Contreras, Juan Carlos; Hernández-Pando, Rogelio; Aparicio-Trejo, Omar Emiliano; Madero, Magdalena; Pedraza-Chaverri, José

    2015-01-01

    It has been shown that curcumin (CUR), a polyphenol derived from Curcuma longa, exerts a protective effect against gentamicin- (GM-) induced nephrotoxicity in rats, associated with a preservation of the antioxidant status. Although mitochondrial dysfunction is a hallmark in the GM-induced renal injury, the role of CUR in mitochondrial protection has not been studied. In this work, LLC-PK1 cells were preincubated 24 h with CUR and then coincubated 48 h with CUR and 8 mM GM. Treatment with CUR attenuated GM-induced drop in cell viability and led to an increase in nuclear factor (erythroid-2)-related factor 2 (Nrf2) nuclear accumulation and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) cell expression attenuating GM-induced losses in these proteins. In vivo, Wistar rats were injected subcutaneously with GM (75 mg/Kg/12 h) during 7 days to develop kidney mitochondrial alterations. CUR (400 mg/Kg/day) was administered orally 5 days before and during the GM exposure. The GM-induced mitochondrial alterations in ultrastructure and bioenergetics as well as decrease in activities of respiratory complexes I and IV and induction of calcium-dependent permeability transition were mostly attenuated by CUR. Protection of CUR against GM-induced nephrotoxicity could be in part mediated by maintenance of mitochondrial functions and biogenesis with some participation of the nuclear factor Nrf2.

  1. DJ-1 Protects Pancreatic Beta Cells from Cytokine- and Streptozotocin-Mediated Cell Death

    OpenAIRE

    Deepak Jain; Gesine Weber; Daniel Eberhard; Mehana, Amir E; Jan Eglinger; Alena Welters; Barbara Bartosinska; Kay Jeruschke; Jürgen Weiss; Günter Päth; Hiroyoshi Ariga; Jochen Seufert; Eckhard Lammert

    2015-01-01

    A hallmark feature of type 1 and type 2 diabetes mellitus is the progressive dysfunction and loss of insulin-producing pancreatic beta cells, and inflammatory cytokines are known to trigger beta cell death. Here we asked whether the anti-oxidant protein DJ-1 encoded by the Parkinson's disease gene PARK7 protects islet cells from cytokine- and streptozotocin-mediated cell death. Wild type and DJ-1 knockout mice (KO) were treated with multiple low doses of streptozotocin (MLDS) to induce inflam...

  2. Prominent role of exopeptidase DPP III in estrogen-mediated protection against hyperoxia in vivo

    Directory of Open Access Journals (Sweden)

    Sandra Sobočanec

    2016-08-01

    We find that DPP III accumulates in the nucleus in response to hyperoxia. Further, we show that combined induction of hyperoxia and E2 administration have an additive effect on the nuclear accumulation of DPP III. The level of nuclear accumulation of DPP III is comparable to nuclear accumulation of Nrf-2 in healthy female mice exposed to hyperoxia. In ovariectomized females exposed to hyperoxia, supplementation of E2 induced upregulation of DPP III, Ho-1, Sirt-1 and downregulation of Ppar-γ. While other cytoprotective mechanisms cannot be excluded, these findings demonstrate a prominent role of DPP III, along with Sirt-1, in the E2-mediated protection against hyperoxia.

  3. The protective effect of salicylic acid on lysozyme against riboflavin-mediated photooxidation

    Science.gov (United States)

    Li, Kun; Wang, Hongbao; Cheng, Lingli; Zhu, Hui; Wang, Mei; Wang, Shi-Long

    2011-06-01

    As a metabolite of aspirin in vivo, salicylic acid was proved to protect lysozyme from riboflavin-mediated photooxidation in this study. The antioxidative properties of salicylic acid were further studied by using time-resolved laser flash photolysis of 355 nm. It can quench the triplet state of riboflavin via electron transfer from salicylic acid to the triplet state of riboflavin with a reaction constant of 2.25 × 10 9 M -1 s -1. Mechanism of antioxidant activities of salicylic acid on lysozyme oxidation was discussed. Salicylic acid can serve as a potential antioxidant to quench the triplet state of riboflavin and reduce oxidative pressure.

  4. Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis

    Science.gov (United States)

    Noor, Zannatun; Watanabe, Koji; Abhyankar, Mayuresh M.; Burgess, Stacey L.; Buonomo, Erica L.

    2017-01-01

    ABSTRACT The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α. PMID:28246365

  5. Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis

    Directory of Open Access Journals (Sweden)

    Zannatun Noor

    2017-02-01

    Full Text Available The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25 is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α.

  6. Importance of (antibody-dependent) complement-mediated serum killing in protection against Bordetella pertussis.

    Science.gov (United States)

    Geurtsen, Jeroen; Fae, Kellen C; van den Dobbelsteen, Germie P J M

    2014-10-01

    Pertussis is a highly contagious respiratory disease that is caused by Bordetella pertussis. Despite being vaccine preventable, pertussis rates have been rising steadily over the last decades, even in areas with high vaccine uptake. Recently, experiments with infant baboons indicated that although vaccination with acellular pertussis vaccines prevented disease, no apparent effect was observed on infection and transmission. One explanation may be that current acellular pertussis vaccines do not induce high levels of opsonophagocytic and/or bactericidal activity, implying that engineering of vaccines that promote bacterial killing may improve efficacy. Here, we discuss the importance of complement-mediated killing in vaccine-induced protection against B. pertussis. We first examine how B. pertussis may have evolved different complement evasion strategies. Second, we explore the benefits of opsonophagocytic and/or bactericidal killing in vaccine-induced protection and discuss whether or not inclusion of new opsonophagocytic or bactericidal target antigens in pertussis vaccines may benefit efficacy.

  7. Calcium signaling-mediated endogenous protection of cell energetics in the acutely diabetic myocardiumThis article is one of a selection of papers published in a special issue on Advances in Cardiovascular Research

    National Research Council Canada - National Science Library

    Cagalinec, Michal; Ziegelhoeffer, Tibor; Mujkošová, Jana; Ziegelhöffer, Barbara; Waczulíková, Iveta; Ziegelhöffer, Attila; Šikurová, Libuša; Kincelová, Dana; Schönburg, Markus; Uli čná, O ľga; Ravingerová, Tá ňa; Ferko, Miroslav

    2009-01-01

    In acute diabetic myocardium, calcium signals propagated by intracellular calcium transients participate in the protection of cell energetics via upregulating the formation of mitochondrial energy transition pores (ETP...

  8. Overexpression of DNA ligase III in mitochondria protects cells against oxidative stress and improves mitochondrial DNA base excision repair.

    Science.gov (United States)

    Akbari, Mansour; Keijzers, Guido; Maynard, Scott; Scheibye-Knudsen, Morten; Desler, Claus; Hickson, Ian D; Bohr, Vilhelm A

    2014-04-01

    Base excision repair (BER) is the most prominent DNA repair pathway in human mitochondria. BER also results in a temporary generation of AP-sites, single-strand breaks and nucleotide gaps. Thus, incomplete BER can result in the generation of DNA repair intermediates that can disrupt mitochondrial DNA replication and transcription and generate mutations. We carried out BER analysis in highly purified mitochondrial extracts from human cell lines U2OS and HeLa, and mouse brain using a circular DNA substrate containing a lesion at a specific position. We found that DNA ligation is significantly slower than the preceding mitochondrial BER steps. Overexpression of DNA ligase III in mitochondria improved the rate of overall BER, increased cell survival after menadione induced oxidative stress and reduced autophagy following the inhibition of the mitochondrial electron transport chain complex I by rotenone. Our results suggest that the amount of DNA ligase III in mitochondria may be critical for cell survival following prolonged oxidative stress, and demonstrate a functional link between mitochondrial DNA damage and repair, cell survival upon oxidative stress, and removal of dysfunctional mitochondria by autophagy.

  9. Methanol extract of Desmodium gangeticum roots preserves mitochondrial respiratory enzymes, protecting rat heart against oxidative stress induced by reperfusion injury.

    Science.gov (United States)

    Kurian, Gino A; Yagnesh, N; Kishan, R Sanchit; Paddikkala, Jose

    2008-04-01

    Ischaemia and reperfusion result in mitochondrial dysfunction, with decreased oxidative capacity, loss of cytochrome c and generation of reactive oxygen species. The aim of this study was to evaluate the effect of a methanol extract of Desmodium gangeticum (L) DC (Fabaceae) (DG) on lipid peroxidation and antioxidants in mitochondria and tissue homogenates of normal, ischaemic and ischaemia-reperfused rats. Myocardial lipid peroxidation products (thiobarbituric acid reactive substances; TBARS) in cardiac tissue homogenates and mitochondrial fractions were significantly increased during ischaemia reperfusion. Antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase (GPx) and glutathione reductase) in the myocardial tissue homogenate and mitochondria decreased significantly during ischaemia reperfusion, accompanied by a decreased activity of mitochondrial respiratory enzymes. Daily pretreatment of rats with DG (50 or 100 mgkg(-1)) orally for 30 days had a significant effect on the activity of mitochondrial and antioxidant enzymes. In-vitro studies showed that DG inhibited lipid peroxidation, and also scavenged hydroxyl and superoxide radicals. The concentrations required to scavenge 50% of the superoxide and hydroxyl radicals were 21 and 50.5 microgmL(-1), respectively. Administration of DG to normal rats did not have any significant effect on any of the parameters studied. The results of our study showed that DG possesses the ability to scavenge the free radicals generated during ischaemia and ischaemia reperfusion and thereby preserves the mitochondrial respiratory enzymes that eventually lead to cardioprotection.

  10. Role of mitochondrial dysfunction in neurotoxicity of MPP+: partial protection of PC12 cells by acetyl-L-carnitine.

    Science.gov (United States)

    Virmani, Ashraf; Gaetani, Franco; Binienda, Zbigniew; Xu, Alex; Duhart, Helen; Ali, Syed F

    2004-10-01

    The damage to the central nervous system that is observed after administration of either methamphetamine (METH) or 1-methyl-4-phenylpyridinium (MPP+), the neurotoxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), is known to be linked to dopamine (DA). The underlying neurotoxicity mechanism for both METH and MPP+ seem to involve free radical formation and impaired mitochondrial function. The MPP+ is thought to selectively kill nigrostriatal dopaminergic neurons by inhibiting mitochondrial complex I, with cell death being attributed to oxidative stress damage to these vulnerable DA neurons. In the present study, MPP+ was shown to significantly inhibit the response to MTT by cultured PC12 cells. This inhibitory action of MPP+ could be partially reversed by the co-incubation of the cells with the acetylated form of carnitine, acetyl-L-carnitine (ALC). Since at least part of the toxic action of MPP+ is related to mitochondrial inhibition, the partial reversal of the inhibition of MTT response by ALC could involve a partial restoration of mitochondrial function. The role carnitine derivatives, such as ALC, play in attenuating MPP+ and METH-evoked toxicity is still under investigation to elucidate the contribution of mitochondrial dysfunction in mechanisms of neurotoxicity.

  11. L-Lactate protects neurons against excitotoxicity: implication of an ATP-mediated signaling cascade

    KAUST Repository

    Jourdain, P.

    2016-02-19

    Converging experimental data indicate a neuroprotective action of L-Lactate. Using Digital Holographic Microscopy, we observe that transient application of glutamate (100 μM; 2 min) elicits a NMDA-dependent death in 65% of mouse cortical neurons in culture. In the presence of L-Lactate (or Pyruvate), the percentage of neuronal death decreases to 32%. UK5099, a blocker of the Mitochondrial Pyruvate Carrier, fully prevents L-Lactate-mediated neuroprotection. In addition, L-Lactate-induced neuroprotection is not only inhibited by probenicid and carbenoxolone, two blockers of ATP channel pannexins, but also abolished by apyrase, an enzyme degrading ATP, suggesting that ATP produced by the Lactate/Pyruvate pathway is released to act on purinergic receptors in an autocrine/paracrine manner. Finally, pharmacological approaches support the involvement of the P2Y receptors associated to the PI3-kinase pathway, leading to activation of KATP channels. This set of results indicates that L-Lactate acts as a signalling molecule for neuroprotection against excitotoxicity through coordinated cellular pathways involving ATP production, release and activation of a P2Y/KATP cascade.

  12. Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing.

    Directory of Open Access Journals (Sweden)

    Caroline B Madsen

    Full Text Available Membrane bound mucins are up-regulated and aberrantly glycosylated during malignant transformation in many cancer cells. This results in a negatively charged glycoprotein coat which may protect cancer cells from immune surveillance. However, only limited data have so far demonstrated the critical steps in glycan elongation that make aberrantly glycosylated mucins affect the interaction between cancer cells and cytotoxic effector cells of the immune system. Tn (GalNAc-Ser/Thr, STn (NeuAcα2-6GalNAc-Ser/Thr, T (Galβ1-3GalNAc-Ser/Thr, and ST (NeuAcα2-6Galβ1-3GalNAc-Ser/Thr antigens are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing only the shortest possible mucin-like glycans (Tn and STn. Glyco-engineering was performed by zinc finger nuclease (ZFN knockout (KO of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast and pancreatic cancer cell lines T47D and Capan-1 increases sensitivity to both NK cell mediated antibody-dependent cellular-cytotoxicity (ADCC and cytotoxic T lymphocyte (CTL-mediated killing. In addition, we investigated the association between total cell surface expression of MUC1/MUC16 and NK or CTL mediated killing, and observed an inverse correlation between MUC16/MUC1 expression and the sensitivity to ADCC and CTL-mediated killing. Together, these data suggest that up-regulation of membrane bound mucins protects cells from immune mediated killing, and that particular glycosylation steps, as demonstrated for glycan elongation beyond Tn and STn, can be important for fine tuning of the immune escape mechanisms in cancer cells.

  13. Wolbachia-mediated antiviral protection in Drosophila larvae and adults following oral infection.

    Science.gov (United States)

    Stevanovic, Aleksej L; Arnold, Pieter A; Johnson, Karyn N

    2015-12-01

    Understanding viral dynamics in arthropods is of great importance when designing models to describe how viral spread can influence arthropod populations. The endosymbiotic bacterium Wolbachia spp., which is present in up to 40% of all insect species, has the ability to alter viral dynamics in both Drosophila spp. and mosquitoes, a feature that in mosquitoes may be utilized to limit spread of important arboviruses. To understand the potential effect of Wolbachia on viral dynamics in nature, it is important to consider the impact of natural routes of virus infection on Wolbachia antiviral effects. Using adult Drosophila strains, we show here that Drosophila-Wolbachia associations that have previously been shown to confer antiviral protection following systemic viral infection also confer protection against virus-induced mortality following oral exposure to Drosophila C virus in adults. Interestingly, a different pattern was observed when the same fly lines were challenged with the virus when still larvae. Analysis of the four Drosophila-Wolbachia associations that were protective in adults indicated that only the w1118-wMelPop association conferred protection in larvae following oral delivery of the virus. Analysis of Wolbachia density using quantitative PCR (qPCR) showed that a high Wolbachia density was congruent with antiviral protection in both adults and larvae. This study indicates that Wolbachia-mediated protection may vary between larval and adult stages of a given Wolbachia-host combination and that the variations in susceptibility by life stage correspond with Wolbachia density. The differences in the outcome of virus infection are likely to influence viral dynamics in Wolbachia-infected insect populations in nature and could also have important implications for the transmission of arboviruses in mosquito populations.

  14. Implications of astrocytes in mediating the protective effects of Selective Estrogen Receptor Modulators upon brain damage

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2015-04-01

    Full Text Available Selective Estrogen Receptor Modulators (SERMs are steroidal or non-steroidal compounds that are already used in clinical practice for the treatment of breast cancer, osteoporosis and menopausal symptoms. While SERMs actions in the breast, bone, and uterus have been well characterized, their actions in the brain are less well understood. Previous works have demonstrated the beneficial effects of SERMs in different chronic neurodegenerative diseases like Alzheimer, Parkinson’s disease and Multiple sclerosis, as well as acute degeneration as stroke and traumatic brain injury. Moreover, these compounds exhibit similar protective actions as those of estradiol in the Central Nervous System, overt any secondary effect. For these reasons, in the past few years, there has been a growing interest in the neuroprotective effects exerted directly or indirectly by SERMs in the SNC. In this context, astrocytes play an important role in the maintenance of brain metabolism, and antioxidant support to neurons, thus indicating that better protection of astrocytes are an important asset targeting neuronal protection. Moreover, various clinical and experimental studies have reported that astrocytes are essential for the neuroprotective effects of SERMs during neuronal injuries, as these cells express different estrogen receptors in cell membrane, demonstrating that part of SERMs effects upon injury may be mediated by astrocytes. The present work highlights the current evidence on the protective mechanisms of SERMs, such as tamoxifen and raloxifene, in the SNC, and their modulation of astrocytic properties as promising therapeutic targets during brain damage.

  15. Role of Eosinophils and Tumor Necrosis Factor Alpha in Interleukin-25-Mediated Protection from Amebic Colitis.

    Science.gov (United States)

    Noor, Zannatun; Watanabe, Koji; Abhyankar, Mayuresh M; Burgess, Stacey L; Buonomo, Erica L; Cowardin, Carrie A; Petri, William A

    2017-02-28

    The parasite Entamoeba histolytica is a cause of diarrhea in infants in low-income countries. Previously, it was shown that tumor necrosis factor alpha (TNF-α) production was associated with increased risk of E. histolytica diarrhea in children. Interleukin-25 (IL-25) is a cytokine that is produced by intestinal epithelial cells that has a role in maintenance of gut barrier function and inhibition of TNF-α production. IL-25 expression was decreased in humans and in the mouse model of amebic colitis. Repletion of IL-25 blocked E. histolytica infection and barrier disruption in mice, increased gut eosinophils, and suppressed colonic TNF-α. Depletion of eosinophils with anti-Siglec-F antibody prevented IL-25-mediated protection. In contrast, depletion of TNF-α resulted in resistance to amebic infection. We concluded that IL-25 provides protection from amebiasis, which is dependent upon intestinal eosinophils and suppression of TNF-α.IMPORTANCE The intestinal epithelial barrier is important for protection from intestinal amebiasis. We discovered that the intestinal epithelial cytokine IL-25 was suppressed during amebic colitis in humans and that protection could be restored in the mouse model by IL-25 administration. IL-25 acted via eosinophils and suppressed TNF-α. This work illustrates a previously unrecognized pathway of innate mucosal immune response. Copyright © 2017 Noor et al.

  16. Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics.

    Science.gov (United States)

    Li, Zhonglei; Tan, Jun; Shao, Lei; Dong, Xiaojing; Ye, Richard D; Chen, Daijie

    2017-05-01

    Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics. Copyright © 2017 Elsevier GmbH. All rights reserved.

  17. TRF2-Mediated Control of Telomere DNA Topology as a Mechanism for Chromosome-End Protection.

    Science.gov (United States)

    Benarroch-Popivker, Delphine; Pisano, Sabrina; Mendez-Bermudez, Aaron; Lototska, Liudmyla; Kaur, Parminder; Bauwens, Serge; Djerbi, Nadir; Latrick, Chrysa M; Fraisier, Vincent; Pei, Bei; Gay, Alexandre; Jaune, Emilie; Foucher, Kevin; Cherfils-Vicini, Julien; Aeby, Eric; Miron, Simona; Londoño-Vallejo, Arturo; Ye, Jing; Le Du, Marie-Hélène; Wang, Hong; Gilson, Eric; Giraud-Panis, Marie-Josèphe

    2016-01-21

    The shelterin proteins protect telomeres against activation of the DNA damage checkpoints and recombinational repair. We show here that a dimer of the shelterin subunit TRF2 wraps ∼ 90 bp of DNA through several lysine and arginine residues localized around its homodimerization domain. The expression of a wrapping-deficient TRF2 mutant, named Top-less, alters telomeric DNA topology, decreases the number of terminal loops (t-loops), and triggers the ATM checkpoint, while still protecting telomeres against non-homologous end joining (NHEJ). In Top-less cells, the protection against NHEJ is alleviated if the expression of the TRF2-interacting protein RAP1 is reduced. We conclude that a distinctive topological state of telomeric DNA, controlled by the TRF2-dependent DNA wrapping and linked to t-loop formation, inhibits both ATM activation and NHEJ. The presence of RAP1 at telomeres appears as a backup mechanism to prevent NHEJ when topology-mediated telomere protection is impaired.

  18. A novel autophagy/mitophagy inhibitor liensinine sensitizes breast cancer cells to chemotherapy through DNM1L-mediated mitochondrial fission.

    Science.gov (United States)

    Zhou, Jing; Li, Guobing; Zheng, Yi; Shen, Han-Ming; Hu, Xiaoye; Ming, Qian-Liang; Huang, Cheng; Li, Peng; Gao, Ning

    2015-01-01

    Autophagy inhibition has been widely accepted as a promising therapeutic strategy in cancer, while the lack of effective and specific autophagy inhibitors hinders its application. Here we found that liensinine, a major isoquinoline alkaloid, inhibits late-stage autophagy/mitophagy through blocking autophagosome-lysosome fusion. This effect is likely achieved via inhibiting the recruitment of RAB7A to lysosomes but not to autophagosomes. We further investigated the effects of autophagy inhibition by liensinine on the therapeutic efficacy of chemotherapeutic drugs and found that cotreatment of liensinine markedly decreased the viability and increased apoptosis in breast cancer cells treated with various chemotherapeutic agents. Mechanistically, we found that inhibition of autophagy/mitophagy by liensinine enhanced doxorubicin-mediated apoptosis by triggering mitochondrial fission, which resulted from dephosphorylation and mitochondrial translocation of DNM1L. However, blocking autophagosome/mitophagosome formation by pharmacological or genetic approaches markedly attenuated mitochondrial fission and apoptosis in cells with combinatatorial treatment. Moreover, liensinine was synergized with doxorubicin to inhibit tumor growth in MDA-MB-231 xenograft in vivo. Our findings suggest that liensinine could potentially be further developed as a novel autophagy/mitophagy inhibitor, and a combination of liensinine with classical chemotherapeutic drugs could represent a novel therapeutic strategy for treatment of breast cancer.

  19. Differential protection by wildtype vs. organelle-specific Bcl-2 suggests a combined requirement of both the ER and mitochondria in ceramide-mediated caspase-independent programmed cell death

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    Belka Claus

    2009-10-01

    Full Text Available Abstract Background Programmed cell death (PCD is essential for development and homeostasis of multicellular organisms and can occur by caspase-dependent apoptosis or alternatively, by caspase-independent PCD (ciPCD. Bcl-2, a central regulator of apoptosis, localizes to both mitochondria and the endoplasmic reticulum (ER. Whereas a function of mitochondrial and ER-specific Bcl-2 in apoptosis has been established in multiple studies, corresponding data for ciPCD do not exist. Methods We utilized Bcl-2 constructs specifically localizing to mitochondria (Bcl-2 ActA, the ER (Bcl-2 cb5, both (Bcl-2 WT or the cytosol/nucleus (Bcl-2 ΔTM and determined their protective effect on ceramide-mediated ciPCD in transiently and stably transfected Jurkat cells. Expression of the constructs was verified by immunoblots. Ceramide-mediated ciPCD was induced by treatment with human recombinant tumor necrosis factor and determined by flow cytometric measurement of propidium iodide uptake as well as by optical analysis of cell morphology. Results Only wildtype Bcl-2 had the ability to efficiently protect from ceramide-mediated ciPCD, whereas expression of Bcl-2 solely at mitochondria, the ER, or the cytosol/nucleus did not prevent ceramide-mediated ciPCD. Conclusion Our data suggest a combined requirement for both mitochondria and the ER in the induction and the signaling pathways of ciPCD mediated by ceramide.

  20. Nephro-protective effects of a ginger extract on cytosolic and mitochondrial enzymes against streptozotocin (STZ)-induced diabetic complications in rats.

    Science.gov (United States)

    Ramudu, Shanmugam Kondeti; Korivi, Mallikarjuna; Kesireddy, Nishanth; Lee, Li-Chen; Cheng, I-Shiung; Kuo, Chia-Hua; Kesireddy, Sathyavelu Reddy

    2011-04-30

    Diabetes is characterized by elevated blood glucose levels and disturbed homeostasis of metabolic enzymes in whole-body. This study aimed to investigate the effect of ginger administration on altered blood glucose levels, intra- and extra-mitochondrial enzymes and tissue injuries in streptozotocin (STZ)-induced diabetic rats. Wistar strain rats (n = 30) were equally divided into 5 groups: normal control (NC), ginger treated (Gt, 200 mg/kg b.w. orally/30 days), diabetic control (DC, 50 mg/kg b.w.), diabetic plus ginger treated (D + Gt) and diabetic plus glibenclamide treated (D + Gli) groups. We found highly elevated blood glucose levels in the diabetic group, and the glucose levels were significantly (P ginger administration. Activities of intra- and extra-mitochondrial enzymes such as glucose-6-phosphate dehydrogenase (G6PD), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and glutamate dehydrogenase (GDH) were significantly (P diabetic rats, while this was significantly reversed by 30 days of ginger treatment. We also observed consistent renal tissue damages in the diabetic rats; however, these injuries recovered in the ginger-treated diabetic rats as shown in histopathological studies. In this study, we demonstrated that an ethanolic extract of ginger could lower the blood glucose levels as well as improve activities of intra- and extra-mitochondrial enzymes in diabetic rats. Our results suggest that ginger extracts could be used as a nephro-protective supplement particularly to reverse diabetic-induced complications.

  1. L-3-n-Butylphthalide Protects HSPB8 K141N Mutation-Induced Oxidative Stress by Modulating the Mitochondrial Apoptotic and Nrf2 Pathways

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    Xiao-Dong Yang

    2017-07-01

    Full Text Available Charcot–Marie–Tooth disease (CMT, also known as hereditary motor and sensory neuropathy, is the most common inherited peripheral nerve disorder. Missense mutations, such as K141N, in the small heat shock protein HSPB8 are known to cause distal hereditary motor neuropathy 2A (dHMN2A or Charcot-Marie-Tooth neuropathy type 2L (CMT2L. However, of critical clinical significance, very few specific therapies for this disease exist. In the present study, we investigated the impact of mutant K141N HSPB8 on mitochondrial distribution and function in a cellular model of CMT2L. Our results indicate that K141N HSPB8 induced mitochondrial aggregation and caused increased oxidative stress injury. As an extraction from Chinese celery Apium graveolens Linn seeds, L-3-n-Butylphthalide (NBP, has been reported to exert many neuroprotective effects, we interrogated whether NBP could elicit a protective effect on the cell injury typically caused by HSPB8 K141N mutations. We found NBP could reverse the pathological processes induced by HSPB8 K141N mutation via an antioxidant effect, modulation of the Bax/Bcl-2 mitochondrial apoptotic and Nrf2 pathways. We propose a novel function of HSPB8, highlighting the consequence of the K141N pathogenic mutation. Furthermore, we suggest NBP may have promising therapeutic potential in the treatment of CMT2L.

  2. Protective Effect of Ubiquinone and Precursors of ItsSynthesis on Mitochondrial Respiratory Chain andActivity of Matrix Metalloproteinases in Animal Tissuesunder Effect of Doxorubicin

    Institute of Scientific and Technical Information of China (English)

    Anatoliy Burlaka[1; Olena Kuchmenko[2; Dmytro Petukhov[3; Iryna Ganusevych[1; Sergiy Lukin[1; Evgeniya Lukyanchuk[1; Evgen Sydoryk[1; Georgiy Donchenko[4

    2015-01-01

    Mitochondrial dysfunction, oxidative stress, and their regulation are important fields of study in modem clinical research.Exogenous CoQ is an efficient therapeutic agent, yet its application has leads to continued suppression of endogenous CoQ synthesis,which limits CoQ applicability. Our aim was to study the state of mitochondrial electron transport chain components, CoQ contentand redox state, superoxide anion radicals and NO production rates, and active MMP-2 and MMP-9 content in rat liver and heartunder treatment with Doxorubicin, CoQ10, and complex preparation of modulators and precursors of CoQ biosynthesis (EPMcomplex). The results demonstrate that treatment with EPM complex and CoQ10 in addition to Doxorubicin administration exertsprotective effect on liver and heart mitochondria, evidenced by restoration of electron transport in respiratory chain, which isexpressed as decreased nitrile complexes formation with Fe-S-proteins and increased ubisemiquinone content. The protective effectsof EPM complex on mitochondrial electron transport chain under Doxorubicin administration is on par with those of CoQ10, anddecreased MMP2 and MMP9 activities signify lessened extracellular matrix destruction. These results demonstrate the viability ofapproaches to correct adverse effects of Doxorubicin by treatment with CoQ10 and e complex of precursors and modulators of itsbiosynthesis.

  3. Prokineticin-2 upregulation during neuronal injury mediates a compensatory protective response against dopaminergic neuronal degeneration

    Science.gov (United States)

    Gordon, Richard; Neal, Matthew L.; Luo, Jie; Langley, Monica R.; Harischandra, Dilshan S.; Panicker, Nikhil; Charli, Adhithiya; Jin, Huajun; Anantharam, Vellareddy; Woodruff, Trent M.; Zhou, Qun-Yong; Kanthasamy, Anumantha G.; Kanthasamy, Arthi

    2016-01-01

    Prokineticin-2 (PK2), a recently discovered secreted protein, regulates important physiological functions including olfactory biogenesis and circadian rhythms in the CNS. Interestingly, although PK2 expression is low in the nigral system, its receptors are constitutively expressed on nigrostriatal neurons. Herein, we demonstrate that PK2 expression is highly induced in nigral dopaminergic neurons during early stages of degeneration in multiple models of Parkinson's disease (PD), including PK2 reporter mice and MitoPark mice. Functional studies demonstrate that PK2 promotes mitochondrial biogenesis and activates ERK and Akt survival signalling pathways, thereby driving neuroprotection. Importantly, PK2 overexpression is protective whereas PK2 receptor antagonism exacerbates dopaminergic degeneration in experimental PD. Furthermore, PK2 expression increased in surviving nigral dopaminergic neurons from PD brains, indicating that PK2 upregulation is clinically relevant to human PD. Collectively, our results identify a paradigm for compensatory neuroprotective PK2 signalling in nigral dopaminergic neurons that could have important therapeutic implications for PD. PMID:27703142

  4. Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

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    Fu-Chao Liu

    2015-01-01

    Full Text Available Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed.

  5. Neonatal Fc receptor expression in dendritic cells mediates protective immunity against colorectal cancer.

    Science.gov (United States)

    Baker, Kristi; Rath, Timo; Flak, Magdalena B; Arthur, Janelle C; Chen, Zhangguo; Glickman, Jonathan N; Zlobec, Inti; Karamitopoulou, Eva; Stachler, Matthew D; Odze, Robert D; Lencer, Wayne I; Jobin, Christian; Blumberg, Richard S

    2013-12-12

    Cancers arising in mucosal tissues account for a disproportionately large fraction of malignancies. Immunoglobulin G (IgG) and the neonatal Fc receptor for IgG (FcRn) have an important function in the mucosal immune system that we have now shown extends to the induction of CD8(+) T cell-mediated antitumor immunity. We demonstrate that FcRn within dendritic cells (DCs) was critical for homeostatic activation of mucosal CD8(+) T cells that drove protection against the development of colorectal cancers and lung metastases. FcRn-mediated tumor protection was driven by DCs activation of endogenous tumor-reactive CD8(+) T cells via the cross-presentation of IgG complexed antigens (IgG IC), as well as the induction of cytotoxicity-promoting cytokine secretion, particularly interleukin-12, both of which were independently triggered by the FcRn-IgG IC interaction in murine and human DCs. FcRn thus has a primary role within mucosal tissues in activating local immune responses that are critical for priming efficient anti-tumor immunosurveillance.

  6. Angiotensin receptor-mediated oxidative stress is associated with impaired cardiac redox signaling and mitochondrial function in insulin-resistant rats.

    Science.gov (United States)

    Vázquez-Medina, José Pablo; Popovich, Irina; Thorwald, Max A; Viscarra, Jose A; Rodriguez, Ruben; Sonanez-Organis, Jose G; Lam, Lisa; Peti-Peterdi, Janos; Nakano, Daisuke; Nishiyama, Akira; Ortiz, Rudy M

    2013-08-15

    Activation of angiotensin receptor type 1 (AT1) contributes to NADPH oxidase (Nox)-derived oxidative stress during metabolic syndrome. However, the specific role of AT1 in modulating redox signaling, mitochondrial function, and oxidative stress in the heart remains more elusive. To test the hypothesis that AT1 activation increases oxidative stress while impairing redox signaling and mitochondrial function in the heart during diet-induced insulin resistance in obese animals, Otsuka Long Evans Tokushima Fatty (OLETF) rats (n = 8/group) were treated with the AT1 blocker (ARB) olmesartan for 6 wk. Cardiac Nox2 protein expression increased 40% in OLETF compared with age-matched, lean, strain-control Long Evans Tokushima Otsuka (LETO) rats, while mRNA and protein expression of the H₂O₂-producing Nox4 increased 40-100%. ARB treatment prevented the increase in Nox2 without altering Nox4. ARB treatment also normalized the increased levels of protein and lipid oxidation (nitrotyrosine, 4-hydroxynonenal) and increased the redox-sensitive transcription factor Nrf2 by 30% and the activity of antioxidant enzymes (SOD, catalase, GPx) by 50-70%. Citrate synthase (CS) and succinate dehydrogenase (SDH) activities decreased 60-70%, whereas cardiac succinate levels decreased 35% in OLETF compared with LETO, suggesting that mitochondrial function in the heart is impaired during obesity-induced insulin resistance. ARB treatment normalized CS and SDH activities, as well as succinate levels, while increasing AMPK and normalizing Akt, suggesting that AT1 activation also impairs cellular metabolism in the diabetic heart. These data suggest that the cardiovascular complications associated with metabolic syndrome may result from AT1 receptor-mediated Nox2 activation leading to impaired redox signaling, mitochondrial activity, and dysregulation of cellular metabolism in the heart.

  7. Cch1p mediates Ca2+ influx to protect Saccharomyces cerevisiae against eugenol toxicity.

    Science.gov (United States)

    Roberts, Stephen K; McAinsh, Martin; Widdicks, Lisa

    2012-01-01

    Eugenol has antifungal activity and is recognised as having therapeutic potential. However, little is known of the cellular basis of its antifungal activity and a better understanding of eugenol tolerance should lead to better exploitation of eugenol in antifungal therapies. The model yeast, Saccharomyces cerevisiae, expressing apoaequorin was used to show that eugenol induces cytosolic Ca(2+) elevations. We investigated the eugenol Ca(2+) signature in further detail and show that exponentially growing cells exhibit Ca(2+) elevation resulting exclusively from the influx of Ca(2+) across the plasma membrane whereas in stationary growth phase cells Ca(2+) influx from intracellular and extracellular sources contribute to the eugenol-induced Ca(2+) elevation. Ca(2+) channel deletion yeast mutants were used to identify the pathways mediating Ca(2+) influx; intracellular Ca(2+) release was mediated by the vacuolar Ca(2+) channel, Yvc1p, whereas the Ca(2+) influx across the plasma membrane could be resolved into Cch1p-dependent and Cch1p-independent pathways. We show that the growth of yeast devoid the plasma membrane Ca(2+) channel, Cch1p, was hypersensitive to eugenol and that this correlated with reduced Ca(2+) elevations. Taken together, these results indicate that a cch1p-mediated Ca(2+) influx is part of an intracellular signal which protects against eugenol toxicity. This study provides fresh insight into the mechanisms employed by fungi to tolerate eugenol toxicity which should lead to better exploitation of eugenol in antifungal therapies.

  8. Cch1p mediates Ca2+ influx to protect Saccharomyces cerevisiae against eugenol toxicity.

    Directory of Open Access Journals (Sweden)

    Stephen K Roberts

    Full Text Available Eugenol has antifungal activity and is recognised as having therapeutic potential. However, little is known of the cellular basis of its antifungal activity and a better understanding of eugenol tolerance should lead to better exploitation of eugenol in antifungal therapies. The model yeast, Saccharomyces cerevisiae, expressing apoaequorin was used to show that eugenol induces cytosolic Ca(2+ elevations. We investigated the eugenol Ca(2+ signature in further detail and show that exponentially growing cells exhibit Ca(2+ elevation resulting exclusively from the influx of Ca(2+ across the plasma membrane whereas in stationary growth phase cells Ca(2+ influx from intracellular and extracellular sources contribute to the eugenol-induced Ca(2+ elevation. Ca(2+ channel deletion yeast mutants were used to identify the pathways mediating Ca(2+ influx; intracellular Ca(2+ release was mediated by the vacuolar Ca(2+ channel, Yvc1p, whereas the Ca(2+ influx across the plasma membrane could be resolved into Cch1p-dependent and Cch1p-independent pathways. We show that the growth of yeast devoid the plasma membrane Ca(2+ channel, Cch1p, was hypersensitive to eugenol and that this correlated with reduced Ca(2+ elevations. Taken together, these results indicate that a cch1p-mediated Ca(2+ influx is part of an intracellular signal which protects against eugenol toxicity. This study provides fresh insight into the mechanisms employed by fungi to tolerate eugenol toxicity which should lead to better exploitation of eugenol in antifungal therapies.

  9. Extracellular but not cytosolic superoxide dismutase protects against oxidant-mediated endothelial dysfunction

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    Erin L. Foresman

    2013-01-01

    Full Text Available Superoxide (O2•− contributes to the development of cardiovascular disease. Generation of O2•− occurs in both the intracellular and extracellular compartments. We hypothesized that the gene transfer of cytosolic superoxide dismutase (SOD1 or extracellular SOD (SOD3 to blood vessels would differentially protect against O2•−-mediated endothelial-dependent dysfunction. Aortic ring segments from New Zealand rabbits were incubated with adenovirus (Ad containing the gene for Escherichia coli β-galactosidase, SOD1, or SOD3. Activity assays confirmed functional overexpression of both SOD3 and SOD1 isoforms in aorta 24 h following gene transfer. Histochemical staining for β-galactosidase showed gene transfer occurred in the endothelium and adventitia. Next, vessels were prepared for measurement of isometric tension in Kreb's buffer containing xanthine. After precontraction with phenylephrine, xanthine oxidase impaired relaxation to the endothelium-dependent dilator acetylcholine (ACh, max relaxation 33±4% with XO vs. 64±3% without XO, p<0.05, whereas relaxation to the endothelium-independent dilator sodium nitroprusside was unaffected. In the presence of XO, maximal relaxation to ACh was improved in vessels incubated with AdSOD3 (55±2%, p<0.05 vs. control but not AdSOD1 (34±4%. We conclude that adenoviral-mediated gene transfer of SOD3, but not SOD1, protects the aorta from xanthine/XO-mediated endothelial dysfunction. These data provide important insight into the location and enzymatic source of O2•− production in vascular disease.

  10. Protective effect of montelukast against quinolinic acid/malonic acid induced neurotoxicity: possible behavioral, biochemical, mitochondrial and tumor necrosis factor-α level alterations in rats.

    Science.gov (United States)

    Kalonia, H; Kumar, P; Kumar, A; Nehru, B

    2010-11-24

    The present study has been designed to explore the protective effect of montelukast (leukotriene receptor antagonist) against intrastriatal quinolinic acid (QA; 300 nmol) and malonic acid (MA; 6 μmol) induced Huntington's like symptoms in rats. Quinolinic acid has been reported to induce excitotoxicity by stimulating the N-methyl-D-aspartate receptor, causing calcium overload which in turn leads to the neurodegeneration. On the other hand, MA, being a reversible inhibitor of mitochondrial enzyme complex-II, leads to energy crisis and free radical generation. Recent studies have reported the therapeutic potential of leukotriene receptor antagonists in different neurodegenerative disorders. However, their exact role is yet to be established. The present study accordingly, is an attempt to investigate the effect of montelukast against QA and MA induced behavioral, biochemical and molecular alterations in rat striatum. Oxidative stress, mitochondrial enzyme complex and tumor necrosis factor-alpha (TNF-α) were evaluated on day 21st and 14th post intrastriatal QA and MA treatment, respectively. Findings of the present study demonstrate significant alteration in the locomotor activity and motor coordination as well as oxidative burden (increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidants), mitochondrial enzyme complex (I, II and IV) activities and TNF-α level, in both intrastriatal QA and MA treated animals. Further, montelukast (0.4, 0.8 mg/kg p.o.) treatment for 21 and 14 days respectively, attenuated the behavioral alterations, oxidative stress, mitochondrial dysfunction and TNF-α level in these models of Huntington's disease in a significant manner. In conclusion, the present study emphasizes the neuroprotective potential of montelukast in the therapeutic management of Huntington like symptoms.

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

    Science.gov (United States)

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

  12. The Protective Effects of Salidroside from Exhaustive Exercise-Induced Heart Injury by Enhancing the PGC-1α–NRF1/NRF2 Pathway and Mitochondrial Respiratory Function in Rats

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    Zheng Ping

    2015-01-01

    Full Text Available Objective. To test the hypothesis that salidroside (SAL can protect heart from exhaustive exercise-induced injury by enhancing mitochondrial respiratory function and mitochondrial biogenesis key signaling pathway PGC-1α–NRF1/NRF2 in rats. Methods. Male Sprague-Dawley rats were divided into 4 groups: sedentary (C, exhaustive exercise (EE, low-dose SAL (LS, and high-dose SAL (HS. After one-time exhaustive swimming exercise, we measured the changes in cardiomyocyte ultrastructure and cardiac marker enzymes and mitochondrial electron transport system (ETS complexes activities in situ. We also measured mitochondrial biogenesis master regulator PGC-1α and its downstream transcription factors, NRF1 and NRF2, expression at gene and protein levels. Results. Compared to C group, the EE group showed marked myocardium ultrastructure injury and decrease of mitochondrial respiratory function P<0.05 and protein levels of PGC-1α, NRF1, and NRF2 P<0.05 but a significant increase of PGC-1α, NRF1, and NRF2 genes levels P<0.05; compared to EE group, SAL ameliorated myocardium injury, increased mitochondrial respiratory function P<0.05, and elevated both gene and protein levels of PGC-1α, NRF-1, and NRF-2. Conclusion. Salidroside can protect the heart from exhaustive exercise-induced injury. It might act by improving myocardial mitochondrial respiratory function by stimulating the expression of PGC-1α–NRF1/NRF2 pathway.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cheshchevik, V.T. [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Department of Biochemistry, Yanka Kupala Grodno State University, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Lapshina, E.A.; Dremza, I.K.; Zabrodskaya, S.V. [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Reiter, R.J. [Department of Cellular and Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229–3900 (United States); Prokopchik, N.I. [Grodno State Medical University, Gorkogo - 80, 230015 Grodno (Belarus); Zavodnik, I.B., E-mail: zavodnik_il@mail.ru [Institute for Pharmacology and Biochemistry, National Academy of Sciences of Belarus, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus); Department of Biochemistry, Yanka Kupala Grodno State University, Len. Kom. Blvd. - 50, 230017 Grodno (Belarus)

    2012-06-15

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

  14. Protein Kinase C Epsilon Promotes Cerebral Ischemic Tolerance Via Modulation of Mitochondrial Sirt5

    Science.gov (United States)

    Morris-Blanco, Kahlilia C.; Dave, Kunjan R.; Saul, Isabel; Koronowski, Kevin B.; Stradecki, Holly M.; Perez-Pinzon, Miguel A.

    2016-01-01

    Sirtuin 5 (SIRT5) is a mitochondrial-localized NAD+-dependent lysine desuccinylase and a major regulator of the mitochondrial succinylome. We wanted to determine whether SIRT5 is activated by protein kinase C epsilon (PKCε)-mediated increases in mitochondrial Nampt and whether SIRT5 regulates mitochondrial bioenergetics and neuroprotection against cerebral ischemia. In isolated mitochondria from rat cortical cultures, PKCε activation increased SIRT5 levels and desuccinylation activity in a Nampt-dependent manner. PKCε activation did not lead to significant modifications in SIRT3 activity, the major mitochondrial lysine deacetylase. Assessments of mitochondrial bioenergetics in the cortex of wild type (WT) and SIRT5−/− mice revealed that SIRT5 regulates oxygen consumption in the presence of complex I, complex II, and complex IV substrates. To explore the potential role of SIRT5 in PKCε-mediated protection, we compared WT and SIRT5−/− mice by employing both in vitro and in vivo ischemia paradigms. PKCε-mediated decreases in cell death following oxygen-glucose deprivation were abolished in cortical cultures harvested from SIRT5−/− mice. Furthermore, PKCε failed to prevent cortical degeneration following MCAO in SIRT5−/− mice. Collectively this demonstrates that SIRT5 is an important mitochondrial enzyme for protection against metabolic and ischemic stress following PKCε activation in the brain. PMID:27435822

  15. SIRT IS REQUIRED FOR EDP-MEDIATED PROTECTIVE RESPONSES TOWARD HYPOXIA-REOXYGEANTION INJURY IN CARDIAC CELLS

    Directory of Open Access Journals (Sweden)

    Victor eSamokhvalov

    2016-05-01

    Full Text Available Hypoxia-reoxygenation (H/R injury is known to cause extensive injury to cardiac myocardium promoting development of cardiac dysfunction. Despite the vast number of studies dedicated to studying H/R injury, the molecular mechanisms behind it are multiple, complex and remain very poorly understood, which makes development of novel pharmacological agents challenging. Docosahexaenoic acid (DHA, 22:6n3 is an n-3 polyunsaturated fatty acid (PUFA obtained from dietary sources, which produces numerous effects including regulation of cell survival and death mechanisms. The beneficial effects of DHA toward the cardiovascular system are well documented but the relative role of DHA or one of its more potent metabolites is unresolved. Emerging evidence indicates that cytochrome P450 (CYP epoxygenase metabolites of DHA, epoxydocosapentaenoic acids (EDPs, have more potent biological activity than DHA in cardiac cells. In this study we examined whether EDPs protect HL-1 cardiac cells from H/R injury. Our observations demonstrate that treatment with 19,20-EDP protected HL-1 cardiac cells from H/R damage through a mechanism(s protecting and enhancing mitochondrial quality. EDP treatment increased the relative rates of mitobiogenesis and mitochondrial respiration in control and H/R exposed cardiac cells. The observed EDP protective response toward H/R injury involved SIRT1-dependent pathways.

  16. SIRT Is Required for EDP-Mediated Protective Responses toward Hypoxia-Reoxygenation Injury in Cardiac Cells.

    Science.gov (United States)

    Samokhvalov, Victor; Jamieson, Kristi L; Fedotov, Ilia; Endo, Tomoko; Seubert, John M

    2016-01-01

    Hypoxia-reoxygenation (H/R) injury is known to cause extensive injury to cardiac myocardium promoting development of cardiac dysfunction. Despite the vast number of studies dedicated to studying H/R injury, the molecular mechanisms behind it are multiple, complex, and remain very poorly understood, which makes development of novel pharmacological agents challenging. Docosahexaenoic acid (DHA, 22:6n3) is an n - 3 polyunsaturated fatty acid obtained from dietary sources, which produces numerous effects including regulation of cell survival and death mechanisms. The beneficial effects of DHA toward the cardiovascular system are well documented but the relative role of DHA or one of its more potent metabolites is unresolved. Emerging evidence indicates that cytochrome P450 (CYP) epoxygenase metabolites of DHA, epoxydocosapentaenoic acids (EDPs), have more potent biological activity than DHA in cardiac cells. In this study we examined whether EDPs protect HL-1 cardiac cells from H/R injury. Our observations demonstrate that treatment with 19,20-EDP protected HL-1 cardiac cells from H/R damage through a mechanism(s) protecting and enhancing mitochondrial quality. EDP treatment increased the relative rates of mitobiogenesis and mitochondrial respiration in control and H/R exposed cardiac cells. The observed EDP protective response toward H/R injury involved SIRT1-dependent pathways.

  17. Tissue plasminogen activator-mediated fibrinolysis protects against axonal degeneration and demyelination after sciatic nerve injury.

    Science.gov (United States)

    Akassoglou, K; Kombrinck, K W; Degen, J L; Strickland, S

    2000-05-29

    Tissue plasminogen activator (tPA) is a serine protease that converts plasminogen to plasmin and can trigger the degradation of extracellular matrix proteins. In the nervous system, under noninflammatory conditions, tPA contributes to excitotoxic neuronal death, probably through degradation of laminin. To evaluate the contribution of extracellular proteolysis in inflammatory neuronal degeneration, we performed sciatic nerve injury in mice. Proteolytic activity was increased in the nerve after injury, and this activity was primarily because of Schwann cell-produced tPA. To identify whether tPA release after nerve damage played a beneficial or deleterious role, we crushed the sciatic nerve of mice deficient for tPA. Axonal demyelination was exacerbated in the absence of tPA or plasminogen, indicating that tPA has a protective role in nerve injury, and that this protective effect is due to its proteolytic action on plasminogen. Axonal damage was correlated with increased fibrin(ogen) deposition, suggesting that this protein might play a role in neuronal injury. Consistent with this idea, the increased axonal degeneration phenotype in tPA- or plasminogen-deficient mice was ameliorated by genetic or pharmacological depletion of fibrinogen, identifying fibrin as the plasmin substrate in the nervous system under inflammatory axonal damage. This study shows that fibrin deposition exacerbates axonal injury, and that induction of an extracellular proteolytic cascade is a beneficial response of the tissue to remove fibrin. tPA/plasmin-mediated fibrinolysis may be a widespread protective mechanism in neuroinflammatory pathologies.

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

    Science.gov (United States)

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

    2014-11-01

    Mentha piperita (MP), also known as peppermint, is an aromatic and medicinal plant widely used in the food industry, perfumery and cosmetic, pharmacy and traditional medicine. Its essential oil (EO) displays antimicrobial activity against a range of bacteria and fungi. In this study, we found that MP EO lethal cytotoxicity is associated with increased levels of intracellular reactive oxygen species, mitochondrial fragmentation and chromatin condensation, without loss of the plasma membrane integrity, indicative of an apoptotic process. Overexpression of cytosolic catalase and superoxide dismutases reverted the lethal effects of the EO and of its major component menthol. Conversely, deficiency in Sod1p (cytosolic copper-zinc-superoxide dismutase) greatly increased sensitivity to both agents, but deficiency in Sod2p (mitochondrial manganese superoxide dismutase) only induced sensitivity under respiratory growth conditions. Mentha piperita EO increased the frequency of respiratory deficient mutants indicative of damage to the mitochondrial genome, although increase in mitochondrial thiol oxidation does not seem to be involved in the EO toxicity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  19. Drosophila ref(2)P is required for the parkin-mediated suppression of mitochondrial dysfunction in pink1 mutants.

    Science.gov (United States)

    de Castro, I P; Costa, A C; Celardo, I; Tufi, R; Dinsdale, D; Loh, S H Y; Martins, L M

    2013-10-24

    Autophagy is a critical regulator of organellar homeostasis, particularly of mitochondria. Upon the loss of membrane potential, dysfunctional mitochondria are selectively removed by autophagy through recruitment of the E3 ligase Parkin by the PTEN-induced kinase 1 (PINK1) and subsequent ubiquitination of mitochondrial membrane proteins. Mammalian sequestrome-1 (p62/SQSTM1) is an autophagy adaptor, which has been proposed to shuttle ubiquitinated cargo for autophagic degradation downstream of Parkin. Here, we show that loss of ref(2)P, the Drosophila orthologue of mammalian P62, results in abnormalities, including mitochondrial defects and an accumulation of mitochondrial DNA with heteroplasmic mutations, correlated with locomotor defects. Furthermore, we show that expression of Ref(2)P is able to ameliorate the defects caused by loss of Pink1 and that this depends on the presence of functional Parkin. Finally, we show that both the PB1 and UBA domains of Ref(2)P are crucial for mitochondrial clustering. We conclude that Ref(2)P is a crucial downstream effector of a pathway involving Pink1 and Parkin and is responsible for the maintenance of a viable pool of cellular mitochondria by promoting their aggregation and autophagic clearance.

  20. Nitric oxide accumulation is required to protect against iron-mediated oxidative stress in frataxin-deficient Arabidopsis plants.

    Science.gov (United States)

    Martin, Mariana; Colman, María José Rodríguez; Gómez-Casati, Diego F; Lamattina, Lorenzo; Zabaleta, Eduardo Julián

    2009-02-04

    Frataxin is a mitochondrial protein that is conserved throughout evolution. In yeast and mammals, frataxin is essential for cellular iron (Fe) homeostasis and survival during oxidative stress. In plants, frataxin deficiency causes increased reactive oxygen species (ROS) production and high sensitivity to oxidative stress. In this work we show that a knock-down T-DNA frataxin-deficient mutant of Arabidopsis thaliana (atfh-1) contains increased total and organellar Fe levels. Frataxin deficiency leads also to nitric oxide (NO) accumulation in both, atfh-1 roots and frataxin null mutant yeast. Abnormally high NO production might be part of the defence mechanism against Fe-mediated oxidative stress.

  1. Similar cation channels mediate protection from cerebellar exitotoxicity by exercise and inheritance.

    Science.gov (United States)

    Ben-Ari, Shani; Ofek, Keren; Barbash, Shahar; Meiri, Hanoch; Kovalev, Eugenia; Greenberg, David Samuel; Soreq, Hermona; Shoham, Shai

    2012-03-01

    Exercise and inherited factors both affect recovery from stroke and head injury, but the underlying mechanisms and interconnections between them are yet unknown. Here, we report that similar cation channels mediate the protective effect of exercise and specific genetic background in a kainate injection model of cerebellar stroke. Microinjection to the cerebellum of the glutamatergic agonist, kainate, creates glutamatergic excito\\xE2\\x80\\x90toxicity characteristic of focal stroke, head injury or alcoholism. Inherited protection and prior exercise were both accompanied by higher cerebellar expression levels of the Kir6.1 ATP-dependent potassium channel in adjacent Bergmann glia, and voltage-gated KVbeta2 and cyclic nucleotide-gated cation HCN1 channels in basket cells. Sedentary FVB/N and exercised C57BL/6 mice both expressed higher levels of these cation channels compared to sedentary C57BL/6 mice, and were both found to be less sensitive to glutamate toxicity. Moreover, blocking ATP-dependent potassium channels with Glibenclamide enhanced kainate-induced cell death in cerebellar slices from the resilient sedentary FVB/N mice. Furthermore, exercise increased the number of acetylcholinesterase-positive fibres in the molecular layer, reduced cerebellar cytokine levels and suppressed serum acetylcholinesterase activity, suggesting anti-inflammatory protection by enhanced cholinergic signalling. Our findings demonstrate for the first time that routine exercise and specific genetic backgrounds confer protection from cerebellar glutamatergic damages by similar molecular mechanisms, including elevated expression of cation channels. In addition, our findings highlight the involvement of the cholinergic anti-inflammatory pathway in insult-inducible cerebellar processes. These mechanisms are likely to play similar roles in other brain regions and injuries as well, opening new venues for targeted research efforts.

  2. Characteristics and function of cardiac mitochondrial nitric oxide synthase.

    Science.gov (United States)

    Dedkova, Elena N; Blatter, Lothar A

    2009-02-15

    TBAP, and reversed by L-arginine supplementation. In the presence of the mtNOS cofactor (6R)-5,6,7,8,-tetrahydrobiopterin (BH(4); 100 microm) mitochondrial ROS generation and PTP opening decreased while mitochondrial NO generation slightly increased. These data demonstrate that mitochondrial Ca(2+) uptake activates mtNOS and leads to NO-mediated protection against opening of the mitochondrial PTP, provided sufficient availability of l-arginine and BH(4). In conclusion, our data show the importance of L-arginine and BH(4) for cardioprotection via regulation of mitochondrial oxidative stress and modulation of PTP opening by mtNOS.

  3. A protective effect of melatonin on intestinal permeability is induced by diclofenac via regulation of mitochondrial function in mice

    Institute of Scientific and Technical Information of China (English)

    Qiao MEI; Lei DIAO; Jian-ming XU; Xiao-chang LIU; Juan JIN

    2011-01-01

    Aim:This study investigated the effect of intragastrically administered melatonin on intestinal mucosal permeability induced by diclofenac in mice.Methods:Intestinal mucosal permeability was induced in mice by intragastric administration of diclofenac(2.5 mg/kg).Melatonin was given intragastrically(10 mg/kg)once per day for 3 d after diclofenac administration.The small intestine was examined macroscopically and microscopically for pathologic jnjury to the iritestinal mucosa.Intestinal mucosal permeability was evaluated by Evans blue and FITC-dextran methods.Mitochondrial functionaI parameters.including mitochondrial membrane potential.mitochondrial ATPase and succinate dehydrogenase(SDH)activity,were assessed.The malondiaIdehyde(MDA)and myeloperoxidase (MPO)levels were determined from small intestinal mucosal homogenates.Results:As compared with control mice.the permeability,pathologic score, MDA and MPO levels and ulceration of the intestinal mucosa were increased significantly by diclofenac treatment,and a broadened junctional complex and enlarged intercellular space were observed by transmission electron microscopy(TEM).Melatonin treatment significantly reduced the intestinal mucosal permeability.pathologic score,MDA,and MPO levels and ulceration of the intestinal mucosa.By TEM, the small intestine villus morphology and intercellular spaces were nearly normal in melatonin-treated mice.At the level of the mitochondria, melatonin treatment significantly restored the activities of ATPase and SDH.Conclusion:The intestinal damage and increased intestinal permeability induced by diclofenac in mice was limited by melatonin:moreover, melatonin preserved several aspects of mitochondrial function.

  4. A sterile sperm caste protects brother fertile sperm from female-mediated death in Drosophila pseudoobscura

    DEFF Research Database (Denmark)

    Holman, Luke; Snook, Rhonda R

    2008-01-01

    Spermicide (i.e., female-mediated sperm death) is an understudied but potentially widespread phenomenon that has important ramifications for the study of sexual conflict, postcopulatory sexual selection, and fertility [1, 2]. Males are predicted to evolve adaptations against spermicide, but few...... antispermicidal mechanisms have been definitively identified. One such adaptation may be the enigmatic infertile sperm morphs or "parasperm" produced by many species, which have been hypothesized to protect their fertile brother "eusperm" from spermicide [2, 3]. Here, we show that female Drosophila pseudoobscura...... reproductive tracts are spermicidal and that the survival of eusperm after exposure to the female tract is highest when males produce many parasperm. This study clarifies the adaptive significance of infertile sperm castes, which has remained elusive in Drosophila and other taxa despite much recent interest [2...

  5. Dermato-protective properties of ergothioneine through induction of Nrf2/ARE-mediated antioxidant genes in UVA-irradiated Human keratinocytes.

    Science.gov (United States)

    Hseu, You-Cheng; Lo, Heng-Wei; Korivi, Mallikarjuna; Tsai, Yu-Cheng; Tang, Meng-Ju; Yang, Hsin-Ling

    2015-09-01

    UVA irradiation-induced skin damage and redox imbalance have been shown to be ameliorated by ergothioneine (EGT), a naturally occurring sulfur-containing amino acid. However, the responsible molecular mechanism with nanomolar concentrations of EGT remains unclear. We investigated the dermato protective efficacies of EGT (125-500nM) against UVA irradiation (15J/cm(2)), and elucidated the underlying molecular mechanism in human keratinocyte-derived HaCaT cells. We found that EGT treatment prior to UVA exposure significantly increased the cell viability and prevented lactate dehydrogenase release into the medium. UVA-induced ROS and comet-like DNA formation were remarkably suppressed by EGT with a parallel inhibition of apoptosis, as evidenced by reduced DNA fragmentation (TUNEL), caspase-9/-3 activation, and Bcl-2/Bax dysregulation. Furthermore, EGT alleviated UVA-induced mitochondrial dysfunction. Dose-dependent increases of antioxidant genes, HO-1, NQO-1, and γ-GCLC and glutathione by EGT were associated with upregulated Nrf2 and downregulated Keap-1 expressions. This was confirmed by increased nuclear accumulation of Nrf2 and inhibition of Nrf2 degradation. Notably, augmented luciferase activity of ARE may explain Nrf2/ARE-mediated signaling pathways behind EGT dermato-protective properties. We further demonstrated that Nrf2 translocation was mediated by PI3K/AKT, PKC, or ROS signaling cascades. This phenomenon was confirmed with suppressed nuclear Nrf2 activation, and consequently diminished antioxidant genes in cells treated with respective pharmacological inhibitors (LY294002, GF109203X, and N-acetylcysteine). Besides, increased basal ROS by EGT appears to be crucial for triggering the Nrf2/ARE signaling pathways. Silencing of Nrf2 or OCTN1 (EGT carrier protein) signaling with siRNA showed no such protective effects of EGT against UVA-induced cell death, ROS, and apoptosis, which is evidence of the vitality of Nrf2 translocation and protective efficacy of EGT

  6. S-52, a novel nootropic compound, protects against β-amyloid induced neuronal injury by attenuating mitochondrial dysfunction.

    Science.gov (United States)

    Gao, Xin; Zheng, Chun Yan; Qin, Guo Wei; Tang, Xi Can; Zhang, Hai Yan

    2012-10-01

    Accumulating evidence suggests that β-amyloid (Aβ)-induced oxidative DNA damage and mitochondrial dysfunction may initiate and contribute to the progression of Alzheimer's disease (AD). This study evaluated the neuroprotective effects of S-52, a novel nootropic compound, on Aβ-induced mitochondrial failure. In an established paradigm of moderate cellular injury induced by Aβ, S-52 was observed to attenuate the toxicity of Aβ to energy metabolism, mitochondrial membrane structure, and key enzymes in the electron transport chain and tricarboxylic acid cycle. In addition, S-52 also effectively inhibited reactive oxygen species accumulation dose dependently not only in Aβ-harmed cells but also in unharmed, normal cells. The role of S-52 as a scavenger of free radicals is involved in the antioxidative effect of this compound. The beneficial effects on mitochondria and oxidative stress extend the neuroprotective effects of S-52. The present study provides crucial information for better understanding the beneficial profiles of this compound and discovering novel potential drug candidates for AD therapy.

  7. Targeting Glial Mitochondrial Function for Protection from Cerebral Ischemia: Relevance, Mechanisms, and the Role of MicroRNAs

    Directory of Open Access Journals (Sweden)

    Le Li

    2016-01-01

    Full Text Available Astrocytes and microglia play crucial roles in the response to cerebral ischemia and are effective targets for stroke therapy in animal models. MicroRNAs (miRs are important posttranscriptional regulators of gene expression that function by inhibiting the translation of select target genes. In astrocytes, miR expression patterns regulate mitochondrial function in response to oxidative stress via targeting of Bcl2 and heat shock protein 70 family members. Mitochondria play an active role in microglial activation, and miRs regulate the microglial neuroinflammatory response. As endogenous miR expression patterns can be altered with exogenous mimics and inhibitors, miR-targeted therapies represent a viable intervention to optimize glial mitochondrial function and improve clinical outcome following cerebral ischemia. In the present article, we review the role that astrocytes and microglia play in neuronal function and fate following ischemic stress, discuss the relevance of mitochondria in the glial response to injury, and present current evidence implicating miRs as critical regulators in the glial mitochondrial response to cerebral ischemia.

  8. Cytotoxicity of Manganese (III) Complex in Human Breast Adenocarcinoma Cell Line Is Mediated by the Generation of Reactive Oxygen Species Followed by Mitochondrial Damage.

    Science.gov (United States)

    Al-Anbaky, Qudes; Al-Karakooly, Zeiyad; Kilaparty, Surya P; Agrawal, Megha; Albkuri, Yahya M; RanguMagar, Ambar B; Ghosh, Anindya; Ali, Nawab

    2016-11-01

    Manganese (Mn) complexes are widely studied because of their important catalytic properties in synthetic and biochemical reactions. A Mn (III) complex of an amidoamine ligand was synthesized using a tetradentate amidoamine ligand. In this study, the Mn (III) complex was evaluated for its biological activity by measuring its cytotoxicity in human breast adenocarcinoma cell line (MCF-7). Cytotoxic effects of the Mn (III) complex were determined using established biomarkers in an attempt to delineate the mechanism of action and the utility of the complex as a potential anticancer drug. The Mn (III) complex induces cell death in a dose- and time-dependent manner as shown by microculture tetrazolium assay, a measure of cytotoxic cell death. Our results demonstrated that cytotoxic effects were significantly increased at higher concentrations of Mn (III) complex and with longer time of treatment. The IC50 (Inhibitor concentration that results in 50% cell death) value of Mn (III) complex in MCF-7 cells was determined to be 2.5 mmol/L for 24 hours of treatment. In additional experiments, we determined the Mn (III) complex-mediated cell death was due to both apoptotic and nonspecific necrotic cell death mechanisms. This was assessed by ethidium bromide/acridine orange staining and flow cytometry techniques. The Mn (III) complex produced reactive oxygen species (ROS) triggering the expression of manganese superoxide dismutase 1 and ultimately damaging the mitochondrial function as is evident by a decline in mitochondrial membrane potential. Treatment of the cells with free radical scavenger, N, N-dimethylthiourea decreased Mn (III) complex-mediated generation of ROS and attenuated apoptosis. Together, these results suggest that the Mn (III) complex-mediated MCF-7 cell death utilizes combined mechanism involving apoptosis and necrosis perhaps due to the generation of ROS.

  9. Protection by salidroside against bone loss via inhibition of oxidative stress and bone-resorbing mediators.

    Directory of Open Access Journals (Sweden)

    Jin-Kang Zhang

    Full Text Available Oxidative stress is a pivotal pathogenic factor for bone loss in mouse model. Salidroside, a phenylpropanoid glycoside extracted from Rhodiola rosea L, exhibits potent antioxidative effects. In the present study, we used an in vitro oxidative stress model induced by hydrogen peroxide (H(2O(2 in MC3T3-E1 cells and a murine ovariectomized (OVX osteoporosis model to investigate the protective effects of salidroside on bone loss and the related mechanisms. We demonstrated that salidroside caused a significant (P<0.05 elevation of cell survival, alkaline phosphatase (ALP staining and activity, calcium deposition, and the transcriptional expression of Alp, Col1a1 and Osteocalcin (Ocn in the presence of H(2O(2. Moreover, salidroside decreased the production of intracellular reactive oxygen species (ROS, and osteoclast differentiation inducing factors such as receptor activator of nuclear factor-kB ligand (RANKL and IL-6 induced by H(2O(2. In vivo studies further demonstrated that salidroside supplementation for 3 months caused a decrease in malondialdehyde (MDA and an increase in reduced glutathione (GSH concentration in blood of ovariectomized mouse (P<0.05, it also improved trabecular bone microarchitecture and bone mineral density in the fourth lumbar vertebra and distal femur. Our study indicated that the protection provided by salidroside in alleviating bone loss was mediated, at least in part, via inhibition of the release of bone-resorbing mediators and oxidative damage to bone-forming cells, suggesting that salidroside can be used as an effective remedy in the treatment or prevention of osteoporosis.

  10. Mechanism of H2S-mediated protection against oxidative stress in Escherichia coli.

    Science.gov (United States)

    Mironov, Alexander; Seregina, Tatyana; Nagornykh, Maxim; Luhachack, Lyly G; Korolkova, Natalya; Lopes, Liubov Errais; Kotova, Vera; Zavilgelsky, Gennady; Shakulov, Rustem; Shatalin, Konstantin; Nudler, Evgeny

    2017-06-06

    Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl. Using a highly sensitive reporter of the global response to DNA damage (SOS) and the TUNEL assay, we show that 3MST-derived H2S protects chromosomal DNA from oxidative damage. We also show that the induction of the CysB regulon in response to oxidative stress depends on 3MST, whereas the CysB-regulated l-cystine transporter, TcyP, plays the principle role in the 3MST-mediated generation of H2S. These findings led us to propose a model to explain the interplay between l-cysteine metabolism, H2S production, and oxidative stress, in which 3MST protects E. coli against oxidative stress via l-cysteine utilization and H2S-mediated sequestration of free iron necessary for the genotoxic Fenton reaction.

  11. Protection by salidroside against bone loss via inhibition of oxidative stress and bone-resorbing mediators.

    Science.gov (United States)

    Zhang, Jin-Kang; Yang, Liu; Meng, Guo-Lin; Yuan, Zhi; Fan, Jing; Li, Dan; Chen, Jian-Zong; Shi, Tian-Yao; Hu, Hui-Min; Wei, Bo-Yuan; Luo, Zhuo-Jing; Liu, Jian

    2013-01-01

    Oxidative stress is a pivotal pathogenic factor for bone loss in mouse model. Salidroside, a phenylpropanoid glycoside extracted from Rhodiola rosea L, exhibits potent antioxidative effects. In the present study, we used an in vitro oxidative stress model induced by hydrogen peroxide (H(2)O(2)) in MC3T3-E1 cells and a murine ovariectomized (OVX) osteoporosis model to investigate the protective effects of salidroside on bone loss and the related mechanisms. We demonstrated that salidroside caused a significant (Psalidroside decreased the production of intracellular reactive oxygen species (ROS), and osteoclast differentiation inducing factors such as receptor activator of nuclear factor-kB ligand (RANKL) and IL-6 induced by H(2)O(2). In vivo studies further demonstrated that salidroside supplementation for 3 months caused a decrease in malondialdehyde (MDA) and an increase in reduced glutathione (GSH) concentration in blood of ovariectomized mouse (Psalidroside in alleviating bone loss was mediated, at least in part, via inhibition of the release of bone-resorbing mediators and oxidative damage to bone-forming cells, suggesting that salidroside can be used as an effective remedy in the treatment or prevention of osteoporosis.

  12. Myeloid HIF-1 is protective in Helicobacter pylori-mediated gastritis.

    Science.gov (United States)

    Matak, Pavle; Heinis, Mylène; Mathieu, Jacques R R; Corriden, Ross; Cuvellier, Sylvain; Delga, Stéphanie; Mounier, Rémi; Rouquette, Alexandre; Raymond, Josette; Lamarque, Dominique; Emile, Jean-François; Nizet, Victor; Touati, Eliette; Peyssonnaux, Carole

    2015-04-01

    Helicobacter pylori infection triggers chronic inflammation of the gastric mucosa that may progress to gastric cancer. The hypoxia-inducible factors (HIFs) are the central mediators of cellular adaptation to low oxygen levels (hypoxia), but they have emerged recently as major transcriptional regulators of immunity and inflammation. No studies have investigated whether H. pylori affects HIF signaling in immune cells and a potential role for HIF in H. pylori-mediated gastritis. HIF-1 and HIF-2 expression was examined in human H. pylori-positive gastritis biopsies. Subsequent experiments were performed in naive and polarized bone marrow-derived macrophages from wild-type (WT) and myeloid HIF-1α-null mice (HIF-1(Δmyel)). WT and HIF-1(Δmyel) mice were inoculated with H. pylori by oral gavage and sacrificed 6 mo postinfection. HIF-1 was specifically expressed in macrophages of human H. pylori-positive gastritis biopsies. Macrophage HIF-1 strongly contributed to the induction of proinflammatory genes (IL-6, IL-1β) and inducible NO synthase in response to H. pylori. HIF-2 expression and markers of M2 macrophage differentiation were decreased in response to H. pylori. HIF-1(Δmyel) mice inoculated with H. pylori for 6 mo presented with a similar bacterial colonization than WT mice but, surprisingly, a global increase of inflammation, leading to a worsening of the gastritis, measured by an increased epithelial cell proliferation. In conclusion, myeloid HIF-1 is protective in H. pylori-mediated gastritis, pointing to the complex counterbalancing roles of innate immune and inflammatory phenotypes in driving this pathology. Copyright © 2015 by The American Association of Immunologists, Inc.

  13. Neuroprotective effects of a mitochondrial K+-ATP channel opener (diazoxide) are mediated by Bcl-2 expression upregulation

    Institute of Scientific and Technical Information of China (English)

    Majid Katebi; Mansooreh Soleimani; Mehdi Mehdizadeh

    2011-01-01

    Mitochondrial K+-ATP (mito-KATP) channels play an important role in cellular function and survival following ischemic stress. The present results revealed that intervention with diazoxide, a mito-KATP channel opener, led to an increase in Bcl-2 expression in the cerebral cortex of rats subjected to cerebral ischemia reperfusion injury. In addition, the intervention also led to clear improvements in neuronal mitochondrial morphology and consciousness post-injury. Glibenclamide, a mito-KATP channel blocker, exhibited the converse effects. Both diazoxide and glibenclamide exerted dose-dependent effects (in particular, at 18 mg/kg diazoxide and 25 mg/kg glibenclamide). These findings suggest that diazoxide exerts a neuroprotective effect on cerebral ischemia reperfusion injury by opening mito-KATP channels and upregulating Bcl-2 expression.

  14. L-carnitine protects against carboplatin-mediated renal injury: AMPK- and PPARα-dependent inactivation of NFAT3.

    Directory of Open Access Journals (Sweden)

    Yuh-Mou Sue

    Full Text Available We have previously shown that carboplatin induces inflammation and apoptosis in renal tubular cells (RTCs through the activation of the nuclear factor of activated T cells-3 (NFAT3 protein by reactive oxygen species (ROS, and that the ROS-mediated activation of NFAT3 is prevented by N-acetyl cysteine and heme oxygenase-1 treatment. In the current study, we investigated the underlying molecular mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Balb/c mice and RTCs were used as model systems. Carboplatin-induced apoptosis in RTCs was examined using terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling. We evaluated the effects of the overexpression of the peroxisome-proliferator-activated receptor alpha (PPARα protein, the knockdown of PPARα gene, and the blockade of AMPK activation and PPARα to investigate the underlying mechanisms of the protective effect of L-carnitine on carboplatin-mediated renal injury. Carboplatin reduced the nuclear translocation, phosphorylation, and peroxisome proliferator responsive element transactivational activity of PPARα. These carboplatin-mediated effects were prevented by L-carnitine through a mechanism dependent on AMPK phosphorylation and subsequent PPARα activation. The activation of PPARα induced cyclooxygenase 2 (COX-2 and prostacyclin (PGI2 synthase expression that formed a positive feedback loop to further activate PPARα. The coimmunoprecipitation of the nuclear factor (NF κB proteins increased following the induction of PPARα by L-carnitine, which reduced NFκB transactivational activity and cytokine expression. The in vivo study showed that the inactivation of AMPK suppressed the protective effect of L-carnitine in carboplatin-treated mice, indicating that AMPK phosphorylation is required for PPARα activation in the L-carnitine-mediated protection of RTC apoptosis caused by carboplatin. The results of our study provide molecular evidence

  15. The Mitochondrial 2-Oxoglutarate Carrier Is Part of a Metabolic Pathway That Mediates Glucose- and Glutamine-stimulated Insulin Secretion*

    OpenAIRE

    Odegaard, Matthew L.; Joseph, Jamie W.; Jensen, Mette V.; Lu, Danhong; Ilkayeva, Olga; Ronnebaum, Sarah M.; Becker, Thomas C.; Newgard, Christopher B.

    2010-01-01

    Glucose-stimulated insulin secretion from pancreatic islet β-cells is dependent in part on pyruvate cycling through the pyruvate/isocitrate pathway, which generates cytosolic α-ketoglutarate, also known as 2-oxoglutarate (2OG). Here, we have investigated if mitochondrial transport of 2OG through the 2-oxoglutarate carrier (OGC) participates in control of nutrient-stimulated insulin secretion. Suppression of OGC in clonal pancreatic β-cells (832/13 cells) and isolated rat islets by adenovirus-...

  16. Implications of mitochondrial DNA mutations and mitochondrial dysfunction in tumorigenesis

    Institute of Scientific and Technical Information of China (English)

    Jianxin Lu; Lokendra Kumar Sharma; Yidong Bai

    2009-01-01

    Alterations in oxidative phosphorylation resulting from mitochondrial dysfunction have long been hypothesized to be involved in tumorigenesis. Mitochondria have recently been shown to play an important role in regulating both programmed cell death and cell proliferation. Furthermore, mitochondrial DNA (mtDNA) mutations have been found in various cancer cells. However, the role of these mtDNA mutations in tumorigenesis remains largely unknown. This review focuses on basic mitochondrial genetics, mtDNA mutations and consequential mitochondrial dysfunction associated with cancer. The potential molecular mechanisms, mediating the pathogenesis from mtDNA mutations and mitochondrial dysfunction to tumorigenesis are also discussed.

  17. PGC-1α mediates mitochondrial biogenesis and oxidative phosphorylation in cancer cells to promote metastasis.

    Science.gov (United States)

    LeBleu, Valerie S; O'Connell, Joyce T; Gonzalez Herrera, Karina N; Wikman, Harriet; Pantel, Klaus; Haigis, Marcia C; de Carvalho, Fernanda Machado; Damascena, Aline; Domingos Chinen, Ludmilla Thome; Rocha, Rafael M; Asara, John M; Kalluri, Raghu

    2014-10-01

    Cancer cells can divert metabolites into anabolic pathways to support their rapid proliferation and to accumulate the cellular building blocks required for tumour growth. However, the specific bioenergetic profile of invasive and metastatic cancer cells is unknown. Here we report that migratory/invasive cancer cells specifically favour mitochondrial respiration and increased ATP production. Invasive cancer cells use the transcription coactivator peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PPARGC1A, also known as PGC-1α) to enhance oxidative phosphorylation, mitochondrial biogenesis and the oxygen consumption rate. Clinical analysis of human invasive breast cancers revealed a strong correlation between PGC-1α expression in invasive cancer cells and the formation of distant metastases. Silencing of PGC-1α in cancer cells suspended their invasive potential and attenuated metastasis without affecting proliferation, primary tumour growth or the epithelial-to-mesenchymal program. Inherent genetics of cancer cells can determine the transcriptome framework associated with invasion and metastasis, and mitochondrial biogenesis and respiration induced by PGC-1α are also essential for functional motility of cancer cells and metastasis.

  18. Grape seed proanthocyanidins (GSPs) inhibit the growth of cervical cancer by inducing apoptosis mediated by the mitochondrial pathway.

    Science.gov (United States)

    Chen, Qing; Liu, Xiao-Fang; Zheng, Peng-Sheng

    2014-01-01

    Grape seed proanthocyanidins (GSPs), a biologically active component of grape seeds, have been reported to possess a wide array of pharmacological and biochemical properties. Recently, the inhibitory effects of GSPs on various cancers have been reported, but their effects on cervical cancer remain unclear. Here, we explored the effect of GSPs on cervical cancer using in vitro and in vivo models. In vitro, the treatment of HeLa and SiHa cells with GSPs resulted in a significant inhibition of cell viability. Further investigation indicated that GSPs led to the dose-dependent induction of apoptosis in cancer cells. The underlying mechanism was associated with increased expression of the pro-apoptotic protein Bak-1, decreased expression of the anti-apoptotic protein Bcl-2, the loss of mitochondrial membrane potential, and the activation of caspase-3, suggesting that GSPs induced cervical cancer cell apoptosis through the mitochondrial pathway. In addition, the administration of GSPs (0.1%, 0.2%, and 0.4%, w/v) as a supplement in drinking water significantly inhibited the tumor growth of HeLa and SiHa cells in athymic nude mice, and the number of apoptotic cells in those tumors was also increased significantly. Taken together, our studies demonstrated that GSPs could inhibit the growth of cervical cancer by inducing apoptosis through the mitochondrial pathway, which provides evidence indicating that GSPs may be a potential chemopreventive and/or chemotherapeutic agent for cervical cancer.

  19. Grape seed proanthocyanidins (GSPs inhibit the growth of cervical cancer by inducing apoptosis mediated by the mitochondrial pathway.

    Directory of Open Access Journals (Sweden)

    Qing Chen

    Full Text Available Grape seed proanthocyanidins (GSPs, a biologically active component of grape seeds, have been reported to possess a wide array of pharmacological and biochemical properties. Recently, the inhibitory effects of GSPs on various cancers have been reported, but their effects on cervical cancer remain unclear. Here, we explored the effect of GSPs on cervical cancer using in vitro and in vivo models. In vitro, the treatment of HeLa and SiHa cells with GSPs resulted in a significant inhibition of cell viability. Further investigation indicated that GSPs led to the dose-dependent induction of apoptosis in cancer cells. The underlying mechanism was associated with increased expression of the pro-apoptotic protein Bak-1, decreased expression of the anti-apoptotic protein Bcl-2, the loss of mitochondrial membrane potential, and the activation of caspase-3, suggesting that GSPs induced cervical cancer cell apoptosis through the mitochondrial pathway. In addition, the administration of GSPs (0.1%, 0.2%, and 0.4%, w/v as a supplement in drinking water significantly inhibited the tumor growth of HeLa and SiHa cells in athymic nude mice, and the number of apoptotic cells in those tumors was also increased significantly. Taken together, our studies demonstrated that GSPs could inhibit the growth of cervical cancer by inducing apoptosis through the mitochondrial pathway, which provides evidence indicating that GSPs may be a potential chemopreventive and/or chemotherapeutic agent for cervical cancer.

  20. Erythropoietin-mediated protection in kidney transplantation: nonerythropoietic EPO derivatives improve function without increasing risk of cardiovascular events.

    Science.gov (United States)

    van Rijt, Willem G; van Goor, Harry; Ploeg, Rutger J; Leuvenink, Henri G D

    2014-03-01

    The protective, nonerythropoietic effects of erythropoietin (EPO) have become evident in preclinical models in renal ischaemia/reperfusion injury and kidney transplantation. However, four recently published clinical trials using high-dose EPO treatment following renal transplantation did not reveal any protective effect for short-term renal function and even reported an increased risk of thrombosis. This review focusses on the current status of protective pathways mediated by EPO, the safety concerns using high EPO dosage and discusses the discrepancies between pre-clinical and clinical studies. The protective effects are mediated by binding of EPO to a heteromeric receptor complex consisting of two β-common receptors and two EPO receptors. An important role for the activation of endothelial nitric oxide synthase is proposed. EPO-mediated cytoprotection still has enormous potential. However, only nonerythropoietic EPO derivatives may induce protection without increasing the risk of cardiovascular events. In preclinical models, nonerythropoietic EPO derivatives,