LOW DOSE ALCOHOL--ATTENUATION OF CARDIAC APOPTOSIS

这项研究的长期目标是了解心脏线粒体如何启动细胞凋亡，以及适度饮酒如何作为一种治疗方式来阻断或延缓与心脏病进展相关的细胞凋亡信号。适量饮酒与冠状动脉疾病风险降低和缺血性损伤风险降低有关。程序性细胞死亡现在似乎在数量上比以前认识到的心肌细胞活力的丧失中发挥更重要的作用。由于缺血性心脏病和细胞凋亡的启动都与细胞内钙代谢的变化有关，我们建议研究线粒体钙与细胞凋亡事件的关系，以及这些途径是如何通过心肌细胞短暂但长期暴露于低浓度酒精来调节的。将监测酒精对心脏细胞骨架的影响，以确保无毒性。我们能够直接可视化和定量的细胞和线粒体的变化，在纵向的方式，通过使用棕榈酸诱导新生大鼠心肌细胞凋亡的文化。通过使用这种方法，我们建议阐明线粒体钙在这一过程中的作用，以及酒精是否会阻止线粒体通透性转变的进展，从而导致膜电位的丧失和随后的细胞死亡信号的激活。通过使用生物化学和显微镜工具的组合，将研究酒精减弱线粒体钙超载导致渗透性转变和细胞色素c释放的能力。我们建议测试酒精饮料的抗氧化特性或酒精的直接作用是否阻断了脑内产生的自由基的释放和随后的线粒体膜电位损失。 最后，我们将研究脂肪酸代谢和神经酰胺形成对信号转导途径的作用，这些信号转导途径可能会因心肌细胞暴露于低水平酒精而单独改变。

The long-term goal of the proposed research is to understand how cardiac mitochondria initiate apoptosis and how moderate alcohol consumption may act as a therapeutic modality to block or to retard apoptotic signaling associated with the progression of heart disease. Moderate alcohol consumption is linked to a lower risk of coronary artery disease and a decreased risk of ischemic injury. Programmed cell death now appears to play a quantitatively more important role in the loss of myocyte viability than previously recognized. Since both ischemic heart disease and the initiation of apoptosis are linked to changes in intracellular calcium metabolism, we propose to examine the relation of mitochondrial calcium to apoptotic events and how these pathways are modulated by brief but chronic exposure of cardiac myocytes to small concentrations of alcohol. Effects of alcohol on the cardiac cytoskeleton will be monitored to assure absence of toxicity. We are able to visualize directly and quantitate cellular and mitochondrial changes in a longitudinal fashion by using palmitate to induce apoptosis in neonatal rat cardiomyocytes in culture. By using this approach, we propose to elucidate the role of mitochondrial calcium in this process and whether alcohol prevents progression to the mitochondrial permeability transition with a loss in membrane potential and subsequent activation of cell death signaling. By using a combination of biochemical and microscopic tools, the ability of alcohol to attenuate mitochondrial calcium overload leading to the permeability transition and cytochrome c release will be studied. We propose to test whether the anti- oxidant properties of alcoholic beverages or whether direct effects of alcohol block the release of mitochondrially-generated free radicals and the subsequent loss of the mitochondrial membrane potential. Finally, we will look at the role of fatty acid metabolism and ceramide formation on signal transduction pathways that may be individually altered by exposure of cardiac myocytes to low levels of alcohol.