Subcellular Regulation of Autophagic Flux in Cardiomyocytes and the Heart

心肌细胞和心脏自噬流的亚细胞调节

• 批准号: 7847857
• 负责人: Roberta A. Gottlieb
• 金额: $ 2.24万
• 依托单位: SAN DIEGO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2010-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7847857
• 关键词: Animal Model; Apoptosis; Autophagocytosis; Binding; Calcium; Cardiac; Cardiac Myocytes; Cell Death; Cell Line; Cells; Chimeric Proteins; Cytoplasmic Organelle; Development; Elements; Failure; Family member; Functional disorder; Heart; Heart failure; Housekeeping; Hypertrophy; Immune response; Infection; Inflammation; Injury; Ischemia; Lead; Lipopolysaccharides; Lysosomes; Measures; Mediating; Membrane; Methods; Mitochondria; Monitor; Myocardial Infarction; Organelles; Pathologic; Physiological Processes; Play; Process; Production; Proteins; Recycling; Regulation; Reperfusion Therapy; Reporter; Role; Sarcoplasmic Reticulum; Set protein; Shapes; Structure; TNF gene; Testing; Therapeutic Agents; Transgenic Animals; Transgenic Mice; Up-Regulation; heart cell; in vivo; novel therapeutics; overexpression; prevent; protein aggregate; public health relevance; response; response to injury; tool

DESCRIPTION (provided by applicant): Autophagy is the process whereby cytoplasmic components including organelles are engulfed by a double membrane structure and targeted for destruction by fusion with a lysosome. This physiologic process occurs as part of normal housekeeping, as a way to recycle proteins, and as a response to injury. It can be used as a mechanism to prevent apoptosis but can also be used to accomplish cell death when apoptosis is blocked. Autophagy plays an important role in the heart's response to ischemia and reperfusion, hypertrophy, and heart failure. We hypothesize that autophagy is selective rather than nonspecific, and that damaged mitochondria may be the preferred target for autophagy in one setting while sarcoplasmic reticulum, contractile elements, or aggresomes may be selective targets in others. We will develop new methods to analyze organelle-selective autophagic flux. Beclin1 is a key regulator of autophagy and contains a Bcl-2-binding domain. We propose to examine the role of Bcl-2 family members in regulating autophagy. We show that Bcl-2 regulation of ER calcium stores also modulates autophagy and we propose to investigate this in greater detail. Mitochondria are targets of autophagy but must undergo fragmentation before they can be engulfed. The regulation of mitochondrial fission and fusion is achieved through a small set of proteins that also modulate apoptosis. We will test the hypothesis that fission proteins modulate autophagy of mitochondria. The existing tools for study of autophagy in vivo are rather limited. Accordingly, we will develop additional in vivo tools, including regulators of autophagy that can be introduced via Tat mediated protein transduction. Autophagy is part of the innate immune response and is upregulated by bacterial lipopolysaccharide (LPS). LPS and the resulting upregulation of TNFalpha have been shown to exacerbate heart failure. We will test the hypothesis that LPS mediated upregulation of autophagy contributes to heart failure. Autophagy is essential for cells to recycle damaged organelles and cytoplasmic components and therefore may play an important protective role after myocardial infarction, but may also contribute to pathologic remodeling. It is important to thoroughly understand autophagy in the heart as it may lead to the development of new therapeutic agents for amelioration of cardiac dysfunction. Public Health Relevance: This project will examine the role of autophagy in the heart using cell lines, primary culture heart cells, and transgenic animal models. Autophagy is the process used by cells to eliminate damaged organelles and protein aggregates. Its role in the heart is poorly understood. Since infection and inflammation increase autophagy and exacerbate heart failure, we hypothesis that autophagy contributes to injury in this context.

描述（由申请人提供）：自噬是包括细胞器在内的细胞质成分被双膜结构吞噬并通过与溶酶体融合而被靶向破坏的过程。这种生理过程是正常内务管理的一部分，是回收蛋白质的一种方式，也是对损伤的反应。它可以用作防止细胞凋亡的机制，但也可以用于当细胞凋亡被阻断时实现细胞死亡。自噬在心脏对缺血和再灌注、肥大和心力衰竭的反应中发挥重要作用。我们假设自噬是选择性的而不是非特异性的，并且受损的线粒体可能是在一种情况下自噬的首选目标，而肌浆网、收缩元件或聚集体可能是其他情况下的选择性目标。我们将开发新方法来分析细胞器选择性自噬通量。 Beclin1 是自噬的关键调节因子，包含 Bcl-2 结合域。我们建议研究 Bcl-2 家族成员在调节自噬中的作用。我们发现 Bcl-2 对 ER 钙储存的调节也调节自噬，我们建议对此进行更详细的研究。线粒体是自噬的目标，但在被吞噬之前必须经历碎片化。线粒体裂变和融合的调节是通过一小组也调节细胞凋亡的蛋白质来实现的。我们将检验裂变蛋白调节线粒体自噬的假设。现有的体内自噬研究工具相当有限。因此，我们将开发更多的体内工具，包括可以通过 Tat 介导的蛋白质转导引入的自噬调节剂。自噬是先天免疫反应的一部分，并被细菌脂多糖 (LPS) 上调。 LPS 和由此产生的 TNFα 上调已被证明会加剧心力衰竭。我们将检验 LPS 介导的自噬上调导致心力衰竭的假设。自噬对于细胞回收受损的细胞器和细胞质成分至关重要，因此可能在心肌梗死后发挥重要的保护作用，但也可能有助于病理重塑。彻底了解心脏中的自噬非常重要，因为它可能有助于开发改善心脏功能障碍的新治疗药物。 公共健康相关性：该项目将使用细胞系、原代培养心脏细胞和转基因动物模型来研究自噬在心脏中的作用。自噬是细胞消除受损细胞器和蛋白质聚集体的过程。人们对它在心脏中的作用知之甚少。由于感染和炎症会增加自噬并加剧心力衰竭，因此我们假设自噬会导致这种情况下的损伤。