n-(4-methoxybenzyl)-n--(5-nitro-1-3-thiazol-2-yl)urea and Necrosis

It is proposed that ischemic preconditioning (PC) initiates signaling that converges on mitochondria and results in cardioprotection. The outcome of this signaling on mitochondrial enzyme complexes is yet to be understood. We therefore used proteomic methods to test the hypothesis that PC and pharmacological preconditioning similarly alter mitochondrial signaling complexes. Langendorff-perfused murine hearts were treated with the specific GSK-3 inhibitor AR-A014418 (GSK Inhib VIII) for 10 min or subjected to four cycles of 5-min ischemia-reperfusion (PC) before 20-min global ischemia and 120-min reperfusion. PC and GSK Inhib VIII both improved recovery of postischemic left ventricular developed pressure, decreased infarct size, and reduced lactate production during ischemia compared with their time-matched controls. We used proteomics to examine mitochondrial protein levels/posttranslational modifications that were common between PC and GSK Inhib VIII. Levels of cytochrome-c oxidase subunits Va and VIb, ATP synthase-coupling factor 6, and cytochrome b-c1 complex subunit 6 were increased while cytochrome c was decreased with PC and GSK Inhib VIII. Furthermore, the amount of cytochrome-c oxidase subunit VIb was found to be increased in PC and GSK Inhib VIII mitochondrial supercomplexes, which are comprised of complexes I, III, and IV. This result would suggest that changes in complex subunits associated with cardioprotection may affect supercomplex composition. Thus the ability of PC and GSK inhibition to alter the expression levels of electron transport complexes will have important implications for mitochondrial function.

Topics: Animals; Blotting, Western; Cardiotonic Agents; Cytochromes c; Electron Transport; Electrophoresis, Polyacrylamide Gel; Energy Metabolism; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Hemodynamics; Ischemic Preconditioning, Myocardial; Mice; Mice, Inbred C57BL; Mitochondria, Heart; Myocardium; Necrosis; Proteome; Thiazoles; Urea

Glycogen synthase kinase-3beta (GSK3beta) role in human immunodeficiency virus(HIV)-associated neurodegeneration has been evidenced by previous investigations. In this study, we investigated the specificity of two GSK3beta-specific inhibitors, AR-A014418 (A) and B6B30 (B) to prevent direct neurotoxicity in primary human neurons exposed to HIV (BaL). Neurons were exposed to HIV (500 pg/ml) for 12-h and 6-day periods in the presence and absence of A (1 microM, 100 nM, 10 nM) and B (50 nM, 5 nM, 500 pM) to investigate acute and ongoing mechanisms of HIV neurotoxicity. Using an lactate dehydrogenase (LDH) assay to assess cytotoxicity, we observed a significant neurotoxic effect of HIV from control values (P < .01) that was not restored via coexposures of all concentrations of A and B. Additionally, no change in LDH levels were observed after 6 days. However, activity of the acute proapoptotic markers caspases 3 and 7 using a luminescence assay were measured and found to be increased by exposure to HIV (BaL) compared to controls (P = .022). This effect was ameliorated via coexposure to all concentrations of A and 50 nM B after 12 h (P < .01) and to all concentrations of A and B after 6 days (P < .01). Overall, the results from this study provide further evidence for the ability of GSK3beta inhibition to be neuroprotective against HIV-associated neurotoxicity by reducing HIV associated procaspase induction. These data support a role for GSK3beta as a potential therapeutic target and may have important clinical implications for treatment of HIV-associated neurocognitive disorder.

Topics: AIDS Dementia Complex; Caspase 3; Caspase 7; Cells, Cultured; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Indoles; L-Lactate Dehydrogenase; Macrophages; Necrosis; Nerve Degeneration; Neurons; Oximes; Thiazoles; Urea