cytochrome-c-t and Alcoholism

Topics: Alcohol Drinking; Alcoholism; Animals; Apoptosis; Calpain; Cardiolipins; Caspase 3; Cytochromes c; Dimethyl Sulfoxide; Ethanol; Isoproterenol; Male; Myocardial Infarction; Myocardium; Rats; Rats, Wistar

Chronic alcohol consumption induces myocardial damage and a type of non-ischemic cardiomyopathy termed alcoholic cardiomyopathy, where mitochondrial ultrastructural damages and suppressed fusion activity promote cardiomyocyte apoptosis. The aim of the present study is to determine the role of mitochondrial fission proteins and/or other proteins that localise on cardiac mitochondria for apoptosis upon ethanol consumption. In vivo and in vitro chronic alcohol exposure increased mitochondrial Drp1 levels but knockdown of the same did not confer cardioprotection in H9c2 cells. These cells displayed downregulated expression of MFN2 and OPA1 for Bak-mediated cytochrome c release and apoptosis. Dysregulated PTEN/AKT cell survival signal in both ethanol treated and Drp1 knockdown cells augmented oxidative stress by promoting  mitochondrial PTEN-L and MFN1 interaction. Inhibiting this interaction with VO-OHpic, a reversible PTEN inhibitor, prevented Bak insertion into the mitochondria and release of cytochrome c to cytoplasm. Thus, our study provides evidence that Drp1-mediated mitochondrial fission is dispensable for ethanol-induced cardiotoxicity and that stress signals induce mitochondrial PTEN-L accumulation for structural and functional dyshomeostasis. Our in vivo results also demonstrates the therapeutic potential of VO-OHpic for habitual alcoholics developing myocardial dysfunction.

Topics: Alcoholism; Animals; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; Cardiomyopathy, Alcoholic; Cell Line; Cytochromes c; Disease Models, Animal; Dynamins; Ethanol; Female; Gene Expression Regulation; GTP Phosphohydrolases; Humans; Mitochondria, Heart; Mitochondrial Proteins; Myocardium; Myocytes, Cardiac; Organometallic Compounds; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Rats; Rats, Wistar; RNA, Small Interfering; Signal Transduction

Uncoupling proteins (UCPs) are anion channels that can decouple the mitochondrial respiratory chain. "Mild uncoupling" of internal respiration reduces free radical production and oxidative cell stress. Chronic alcohol consumption is a potent inducer of oxidative stress in multiple tissues and regulates UCP-2 and -4 expression in the brain. To analyse the impact of chronic alcohol intake on UCP-2 expression in tissues with high endogenous UCP-2 contents, male Wistar rats (n=34) were treated with a 12-week 5% alcohol diet. In the lungs and the spleen of rats with a chronic alcohol diet cytochrome c release from mitochondria was significantly increased. Both organs did not show any altered gene and protein expression of UCP-2. Different to cerebral tissue chronic alcohol consumption has no regulatory effect on UCP-2 gene and protein expression in organs with a high endogenous UCP-2 content. Therefore, chronic alcohol consumption leads to a tissue specific expression of UCP-2.

Topics: Adenosine Triphosphate; Alcoholism; Animals; Brain; Cytochromes c; Gene Expression; Ion Channels; Lung; Male; Mitochondria; Mitochondrial Proteins; Oxidative Stress; Rats; Rats, Wistar; RNA, Messenger; Spleen; Tissue Distribution; Uncoupling Protein 2

Neuropathy and neurocognitive deficits are common among chronic alcohol users, which are believed to be associated with mitochondrial dysfunction in the brain. The specific type of brain mitochondrial respiratory chain complexes (mRCC) that are adversely affected by alcohol abuse has not been studied. Thus, we examined the alterations of mRCC in freshly isolated mitochondria from mice brain that were pair-fed the ethanol (4% v/v) and control liquid diets for 7-8 weeks. We observed that alcohol intake severely reduced the levels of complex I and V. A reduction in complex I was associated with a decrease in carnitine palmitoyltransferase 1 (cPT1) and cPT2 levels. The mitochondrial outer (cPT1) and inner (cPT2) membrane transporter enzymes are specialized in acylation of fatty acid from outer to inner membrane of mitochondria for ATP production. Thus, our results showed that alterations of cPT1 and cPT2 paralleled a decrease β-oxidation of palmitate and ATP production, suggesting that impairment of substrate entry step (complex I function) can cause a negative impact on ATP production (complex V function). Disruption of cPT1/cPT2 was accompanied by an increase in cytochrome C leakage, while reduction of complex I and V paralleled a decrease in depolarization of mitochondrial membrane potential (ΔΨ, monitored by JC-1 fluorescence) and ATP production in alcohol intake. We noted that acetyl-L-carnitine (ALC, a cofactor of cPT1 and cPT2) prevented the adverse effects of alcohol while coenzyme Q10 (CoQ10) was not very effective against alcohol insults. These results suggest that understanding the molecular, biochemical, and signaling mechanisms of the CNS mitochondrial β-oxidation such as ALC can mitigate alcohol related neurological disorders.

Topics: Adenosine Triphosphate; Alcoholism; Animals; Brain; CA1 Region, Hippocampal; Carnitine O-Palmitoyltransferase; Cytochromes c; Electron Transport Chain Complex Proteins; Ethanol; Male; Membrane Potential, Mitochondrial; Mice; Mitochondria; Neurodegenerative Diseases; Oxidation-Reduction; Synaptic Transmission; Time Factors; Ubiquinone

The aim of this study was to demonstrate the existence of alterations in glutathione and cholesterol homeostasis in brain mitochondria from alcoholic rats. Glutathione concentration decreased, whereas oxidized glutathione and cholesterol contents increased in these organelles, suggesting the ethanol-induced generation of reactive oxygen species, and the impairment of mitochondrial uptake of glutathione, possibly due to the increase in cholesterol deposition. The release of apoptogenic proteins was increased after stimulating mitochondria from the brain of alcoholic rats with atractyloside. As a conclusion, chronic alcohol consumption might sensitize brain mitochondria to apoptotic stimuli, and promote the subsequent release of apoptotic proteins.

Topics: Alcoholism; Animals; Apoptosis Regulatory Proteins; Brain; Carrier Proteins; Cholesterol; Cytochromes c; Ethanol; Glutathione; Glutathione Disulfide; Mitochondria; Mitochondrial Proteins; Rats; Rats, Sprague-Dawley