cytochrome-c-t and acetylleucyl-leucyl-norleucinal

Excessive alcohol consumption and alcoholism cause medical problems with high mortality and morbidity rates. In this study we aimed to decrease the alcohol related tissue damage by inhibiting calpain activation which plays an important role in apoptosis and necrosis, in rats with cardiomyopathy induced by acute alcohol consumption. Male Sprague-Dawley rats were separated into four groups (control, vehicle, alcohol and alcohol + inhibitor) with 10 rats in each. Control group received isocaloric maltose while vehicle group received isocaloric maltose with DMSO, and alcohol group received 8 g/kg absolute ethanol by gavage. Inhibitor group received 20 mg/kg calpain inhibitor 1 intraperitonally prior to alcohol administration. Calpain activities, cathepsin L levels and cytochrome c release rates were significantly increased in alcohol group compared to control group (p < 0.05). Serum CK MB and BNP levels of alcohol group were excessively increased compared to control group (respectively p < 0.001 and p < 0.01). Serum BNP levels of alcohol + inhibitor group were significantly (p < 0.05) decreased compared to alcohol group. In addition to these, histological evaluation of light microscope images and the results of DNA fragmentation and immunohistochemical caspase-3 activity results showed significant improvement of these parameters in alcohol + inhibitor group compared to alcohol group. Results of our biochemical and histological evaluation results revealed that the calpain inhibitor N-acetyl-leu-leu-norleucinal may have an ameliorating effect on acute alcohol consumption related cardiac tissue damage due to its effects on cell death pathways.

Topics: Animals; Binge Drinking; Calpain; Cardiomyopathies; Caspase 3; Cathepsin B; Cathepsin L; Creatine Kinase, MB Form; Cysteine Proteinase Inhibitors; Cytochromes c; Disease Models, Animal; Humans; Immunohistochemistry; Leupeptins; Male; Myocardium; Nerve Tissue Proteins

We investigated the response of alphaB-crystallin to oxidative stress and calpain inhibition in an attempt to elucidate the signalling pathways mediating its phosphorylation. Given the high expression levels of alphaB-crystallin in cardiac muscle one can evaluate the significance of its participation in preservation of homeostasis under adverse conditions. H9c2 cardiac myoblasts were used as our experimental model since their response reflects the signal transduction pathways activated by stress conditions in the myocardium. Thus, in H9c2 cells treated with H2O2 the mechanism regulating alphaB-crystallin phosphorylation was found to involve p38-MAPK/MSK1 as well as intracellular free calcium levels. Our immunocytochemical experiments demonstrated phosphorylated alphaB-crystallin to be co-localized with tubulin, potentially preserving cytoskeletal architecture under these interventions. In H9c2 cells treated with calpain inhibitors (ALLN, ALLM) alphaB-crystallin exhibited a p38-MAPK- and [Ca 2+](i)-dependent phosphorylation pattern since the latter was ablated in the presence of the selective p38-MAPK inhibitor SB203580 and calcium chelator BAPTA-AM. Calpain activity repression ultimately led to apoptosis confirmed by PARP fragmentation and chromatin condensation. However, the apoptotic pathway activated by ALLM and ALLN differed, underlying the diverse transduction mechanisms stimulated. In addition to this, an anti-apoptotic role for phospho-alphaB-crystallin was verified by confirmation of its interaction with pro-caspase 3, hindering its cleavage and subsequent activation. Collectively, our findings underline alphaB-crystallin crucial role as a participant of cardiac cells early response to stressful stimuli compromising their survival.

Topics: alpha-Crystallin B Chain; Animals; Apoptosis; Calcium Signaling; Calpain; Caspase 3; Cell Line; Cell Nucleus; Cytochromes c; Egtazic Acid; Hydrogen Peroxide; Leupeptins; Myocytes, Cardiac; Oligopeptides; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Phosphoserine; Poly(ADP-ribose) Polymerases; Protein Transport; Rats; Ribosomal Protein S6 Kinases, 90-kDa; Time Factors; Tubulin