Mechanisms of Ethanol-Induced Cardiac Protection

摘要 十年前，我们发现在心肌缺血前短暂暴露于10-50 mM乙醇可以减少梗死 在依赖于蛋白激酶C（PKC）激活的过程中，其大小约为70%。过去 资金期间，我们发现，激活线粒体酶，醛脱氢酶2，ALDH 2， 似乎是乙醇诱导的心肌缺血保护所必需的和足够的。的重要性 线粒体ALDH 2在人类健康中的增加也表明了40%的东 携带Aldh 2基因失活突变Aldh 2 *2的亚洲人患有多种慢性疾病 与氧化应激和由此产生的有毒醛的积累，包括心肌 梗塞 我们计划使用以下方法来确定乙醇诱导的细胞保护作用是否需要PKC和ALDH 2活性， 基因操作小鼠（AIM 1A）。我们接下来将确定乙醇诱导的细胞凋亡的机制。 胞质PKC进入线粒体，在线粒体中发现ALDH 2（AIM 1B）。 然后我们将 确定乙醇和其他活化剂对ALDH 2的活化是否降低了乙醇加合物的负荷， 降低细胞毒性（AIM 1C）。 我们将确定乙醇中积累的乙醛 治疗，有助于乙醇诱导的心脏保护作用（AIM 1D），并确定乙醇- 诱导的和PKC介导的ALDH 2磷酸化通过以下途径保护ALDH 2活性免于失活： 长链醛和是否与ALDH 2的新的小分子活化剂一起作用， Alda（AIM 1E） 在AIM 2中，我们将研究由于ALDH 2抑制而导致的乙醇诱导的心脏保护作用的丧失， 硝化甘油（NTG）。我们将鉴定抑制NTG诱导的ALDH 2失活的小分子（NTG 耐受性）（AIM 2A，B），并将确定NTG耐受性抑制剂对乙醇诱导的PKC- 在离体和动物模型中介导的心脏保护免受急性缺血性损伤（AIM 2C）。 总之，这些研究将阐明与动物细胞保护相关的基本过程， 野生型和非活性（ALDH 2 *2）形式的ALDH 2以及适度的乙醇消耗如何影响它们。 我们的研究还将提供新的工具，并测试它们作为心肌缺血治疗的应用， 动物模型

Abstract Ten years ago, we found that a brief exposure to 10-50 mM ethanol prior to cardiac ischemia reduces infarct size by ~70% in a process that is dependent on activation of epsilon protein kinase C, ¿PKC. In the past funding period, we found that activation of the mitochondrial enzyme, aldehyde dehydrogenase 2, ALDH2, appears to be required and sufficient for ethanol-induced cardiac protection from ischemia. The importance of mitochondrial ALDH2 in human health is also suggested by the increased propensity of 40% of East Asians that carry an inactivating mutation in the Aldh2 gene, Aldh2*2, to have a variety of chronic diseases associated with oxidative stress and the resulting accumulation of toxic aldehydes, including myocardial infarction. We plan to determine whether ethanol-induced cytoprotection requires ¿PKC and ALDH2 activity, using genetically manipulated mice (AIM 1A). We will next identify the mechanisms that enable ethanol-induced entry of the cytosolic ¿PKC into the mitochondria, where ALDH2 is found, (AIM 1B). We will then determine whether ALDH2 activation by ethanol and other activators reduces aldehydic adduct loads to reduce cytotoxicity (AIM 1C). We will determine whether acetaldehyde, which accumulates on ethanol treatment, contributes to ethanol-induced cardioprotection (AIM 1D) and determine whether ethanol- induced and ¿PKC-mediated phosphorylation of ALDH2 protects ALDH2 activity from inactivation by long chain aldehydes and whether the effect is additive with new small molecule activators of ALDH2, called Alda (AIM 1E). In AIM 2, we will study the loss of ethanol-induced cardioprotection due to ALDH2 inhibition by nitroglycerine (NTG). We will identify small molecule that inhibit NTG-induced ALDH2 inactivation (NTG tolerance) (AIM 2A, B) and will determine the effect of NTG tolerance inhibitors on ethanol-induced ¿PKC- mediated cardioprotection from acute ischemic damage ex vivo and in animal models (AIM 2C). Together, these studies will elucidate fundamental processes associated with cytoprotection in animals with wildtype and inactive (ALDH2*2) form of ALDH2 and how moderate ethanol consumption affects them. Our studies will also provide new tools and test their application as treatment for cardiac ischemia using animal models.