Autophagy in Myocardial Ischemia/Reperfusion

自噬是一种生理过程，其中细胞质组分包括细胞器被吞噬， 双膜结构，并通过溶酶体被靶向破坏。虽然它是一个构成 在心肌中，自噬水平响应于缺血/再灌注而上调 （I/R）和其他可能的病理生理过程。自噬与细胞死亡有关， 不同环境下的细胞保护。我们假设自噬是一种保护性反应， 再灌注心脏我们将建立自噬在离体灌注心脏中的作用， I/R。在模拟I/R的培养的成人心肌细胞中。利用荧光报告分子， 自噬，LC 3-GFP，并将开发新的试剂，包括荧光报告蛋白交付 转导和心脏特异性LC 3-mCherry转基因小鼠。线粒体是重要的靶点， 自噬，我们假设，消除个别受损或功能障碍， 线粒体可以通过阻止活性氧的传播来避免程序性细胞死亡 (ROS)并向线粒体群体的其余部分传递促凋亡信号。我们建议监测 ROS诱导的ROS释放（RIRR）在成人心肌细胞，并评估自噬是否可以发挥作用， 限制RIRR。使用活细胞成像（核心B）。因为自噬与细胞的代谢状态密切相关， 细胞，我们将研究其调节Akt，mTOR和AMP依赖性激酶。结合项目 1，2和3，我们将检查是否细胞保护途径（Akt，己糖激酶，Pim-1，α B-crvstallin） 直接或通过上调自噬稳定线粒体。自噬被抑制， 肥大;我们将检验这样一种假设，即由此产生的受损线粒体的积累可能 导致胸主动脉缩窄后发生衰竭（核心C）。与项目一起 5、我们将研究自噬是否有助于永久性骨关节炎后的健康或病理性重塑。 缺血，并将确定鞘氨醇-1-磷酸信号转导在自噬调节中的作用。 这些研究将描述自噬在心脏健康和疾病中的作用。

Autophagy is a physiologic process whereby cytoplasmic components including organelles are engulfed by a double membrane structure and targeted for destruction via lysosomes. Although it is a constitutive process in the myocardium, the level of autophagy is upregulated in response to ischemia/reperfusion (I/R) and possibly other pathophysiologic processes. Autophagy has been implicated in cell death and cytoprotection in different contexts. We hypothesize that autophagy is a protective response in the reperfused heart. We will establish the role of autophagy in the isolated perfused heart subjected to global I/R. and in cultured adult cardiomvocvtes subjected to simulated I/R. utilizing the fluorescent reporter of autophagy, LC3-GFP, and will develop novel reagents including a fluorescent reporter delivered by protein transduction and a cardiac-specific LC3-mCherry transgenic mouse. Mitochondria are important targets of autophagy in the heart, and we hypothesize that elimination of individual damaged or dysfunctional mitochondria may avert programmed cell death by preventing the propagation of reactive oxygen species (ROS) and pro-apoptotic signals to the remainder of the mitochondrial population. We propose to monitor ROS-induced ROS release (RIRR) in adult cardiomvocvtes and to assess whether autophagy can function to limit RIRR. using live-cell imaging (Core B). Because autophagy is closely tied to the metabolic state of the cell, we will examine its regulation by Akt, mTOR, and AMP-dependent kinase. In conjunction with Projects 1, 2, and 3, we will examine whether cytoprotective pathways (Akt, hexokinase, Pim-1, alphaB-crvstallin) stabilize mitochondria directly or through upregulation of autophagy. Autophagy is suppressed during hypertrophy; we will test the hypothesis that the resulting accumulation of damaged mitochondria may contribute to the development of failure after thoracic aortic constriction (Core C). In conjunction with Project 5, we will examine whether autophagy contributes to healthy or pathologic remodeling after permanent ischemia, and will determine the role of sphingosine-1-phosphate signaling in the regulation of autophagy. These studies will delineate the role of autophagy in cardiac health and disease.