Dysregulation of cardiac signaling in disease and stress

项目摘要 G蛋白偶联受体（GPCR）激酶2（GRK 2）是GPCR再循环和脱敏的关键调节因子 在包括肥大和心力衰竭（HF）在内的几种心脏病中上调。心脏 缺血-再灌注损伤诱导ERK介导的GRK 2在S670磷酸化，这导致 GRK 2从细胞质到线粒体的易位。我们发现在成年心肌细胞中 线粒体GRK 2通过抑制丙酮酸调节葡萄糖介导的氧化磷酸化 脱氢酶是葡萄糖氧化的限速酶。虽然线粒体的生理影响 GRK 2的报道，但线粒体GRK 2如何调节心脏线粒体 新陈代谢.这项提案的重点是从机制上破译GRK 2磷酸化和 线粒体转位调节心脏葡萄糖代谢。此外，我们认为线粒体 GRK 2通过作为心肌梗死（MI）后代谢信号的放大器参与关键代谢信号传导。 pyroptosis-一种新的裂解性细胞死亡机制。因此，我们假设GRK 2在S670的磷酸化是一个可能的机制。 对于心肌细胞反应至关重要，这是改变代谢可用性和心脏损伤的结果。 使用新型GRK-S670 A和两种Gasdermin E小鼠模型，我们提出了两个具体目标：1. 确定mitoGRK 2如何调节心脏线粒体代谢; 2.）评估是否磷酸化 GRK 2在S670处调节心脏焦萎信号传导。总的来说，我们的工作将阐明GRK 2的作用， 心肌细胞中S670的磷酸化以及这种翻译后修饰如何调节代谢 信号传导和慢性损伤反应。这项研究的总体目标是利用新的机制， 用于HF治疗的新药物的开发和鉴定的信号传导。

Project Summary G-protein coupled receptor (GPCR) kinase-2 (GRK2) is a key regulator of GPCR recycling and desensitization that is upregulated in several cardiac pathologies, including hypertrophy and heart failure (HF). Cardiac ischemia-reperfusion injury induces ERK-mediated phosphorylation of GRK2 at S670, which results in the translocation of GRK2 from the cytosol to mitochondria. We discovered that in the adult cardiomyocyte mitochondrial GRK2 regulates glucose-mediated oxidative phosphorylation by inhibiting pyruvate dehydrogenase, the rate limiting enzyme of glucose oxidation. Although the physiological impact of mitochondrial GRK2 was reported, it remains largely unknown how mitochondrial GRK2 regulates cardiac mitochondrial metabolism. This proposal focuses on deciphering mechanistically how GRK2 phosphorylation and mitochondrial translocation regulate cardiac glucose metabolism. Additionally, we propose that mitochondrial GRK2 participates in key metabolic signaling post-myocardial infarction (MI) by acting as an amplifier of pyroptosis- a novel lytic cell death mechanism. Thus, we hypothesize that GRK2 phosphorylation at S670 is paramount for cardiomyocyte responses in consequence of altering metabolic availability and cardiac injury. Using a novel GRK-S670A and two Gasdermin E mouse models, we propose to carry out two specific aims: 1.) Determine how mitoGRK2 regulates cardiac mitochondrial metabolism; 2.) Assess whether phosphorylation of GRK2 at S670 modulates cardiac pyroptotic signaling. Overall, our work will shed light on the role of GRK2 phosphorylation at S670 in cardiomyocytes and how this post-translational modification regulates metabolic signaling and chronic-injury responses. The overarching goal of this research is to exploit novel mechanistic signaling for the development and identification of new pharmaceutical drugs for HF treatment.