LOW DOSE ALCOHOL--ATTENUATION OF CARDIAC APOPTOSIS

这项拟议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凋亡信号。适度饮酒与冠状动脉疾病的风险降低和缺血性损伤的风险降低有关。程序性细胞死亡现在似乎在肌细胞活力丧失中发挥了比以前认识到的更重要的定量作用。由于缺血性心脏病和细胞凋亡的开始都与细胞内钙代谢的变化有关，我们建议研究线粒体钙与凋亡事件的关系，以及心肌细胞短暂但长期暴露于低浓度酒精如何调节这些途径。将监测酒精对心脏细胞骨架的影响，以确保没有毒性。通过使用棕榈酸盐诱导培养的新生大鼠心肌细胞凋亡，我们能够直观和定量地观察细胞和线粒体的纵向变化。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，以及酒精是否会通过膜电位的丧失和随后的细胞死亡信号的激活来阻止线粒体通透性转变的进展。通过结合使用生化和显微镜工具，将研究酒精减轻线粒体钙超载导致通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会阻止线粒体产生的自由基的释放和随后的线粒体膜电位的丧失。最后，我们将研究脂肪酸代谢和神经酰胺形成在信号转导途径中的作用，这些信号转导途径可能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.