Promoting Cardiomyocyte Cell Cycle Activity and Cardiac Regeneration through IL13 Signaling

标题：通过IL13信号通路促进心肌细胞周期活动和心脏再生 项目摘要 在美国，近600万人患有心力衰竭(HF)，这给国家造成的损失估计为 每年307亿美元。当心脏泵血能力降低时，就会发生心衰，这通常是由 由于心肌的收缩能力减弱。研究低等脊椎动物的心脏再生提供了一个 独一无二的机会，阐明促再生机制，以恢复心脏的功能。有趣的是， 新生小鼠在其出生的第一周内具有再生心肌的能力。以前的工作 发现白细胞介素13(IL13)在直接刺激心肌细胞周期活动和新生儿中的作用 小鼠心脏再生。IL13通过IL4Ra/IL13Ra1异二聚体受体传递信号，这是 在成年期存在于心肌细胞中。观察IL4ra基因敲除的初步实验 表明与野生型小鼠相比，细胞周期活动减弱，心脏再生不足 控制。此外，出生7天的非再生小鼠的DNA合成和心肌梗死恢复也得到了改善 当给予外源性IL13时。总体而言，这一建议解决了IL13信号 增强新生儿和成人的心肌细胞周期活性和促进心脏再生 老鼠。以下提议的实验将研究IL13信号的心脏再生潜力 内生的和外生的。特定目标1将测试IL4Ra/IL13Ra1耗尽在 心肌细胞会抑制细胞周期活动和心脏再生。在体外和体内的实验都将 评估IL13对心肌细胞的内源性作用。活体实验将检验 具有心肌细胞特异性的新小鼠模型(IL4Rafl/fl Myh6CRE)的再生潜能 IL4Ra的耗竭。目标2将解决这一假说，即外源性给药IL13将促进 成年小鼠的心脏再生和细胞周期活性。心肌梗死将在8-10周内诱发 老年小鼠，每天给予重组IL-13，连续4周。收集后，心功能 并通过组织学、定量聚合酶链式反应、BrdU/EDU掺入等方法分析其增殖潜能。 超声心动图。

Title: Promoting Cardiomyocyte Cell Cycle Activity and Cardiac Regeneration through IL13 Signaling Project Summary Close to 6 million people in the United States have heart failure (HF), which costs the nation an estimated $30.7 billion each year. HF occurs when the heart has a reduced ability to pump blood which is usually caused by diminished contractility of the myocardium. Studying cardiac regeneration in lower vertebrates provides a unique opportunity to elucidate pro-regenerative mechanisms to restore function in the heart. Interestingly, the neonatal mouse contains the ability to regenerate myocardium during its first week of life. Previous work uncovered a role for Interleukin 13 (IL13) in directly stimulating cardiomyocyte cell cycle activity and neonatal cardiac regeneration in the mouse. IL13 signals through the IL4Ra/IL13Ra1 heterodimer receptor, which is present on cardiomyocytes through adulthood. Preliminary experiments looking at the knockout of IL4Ra indicate diminished cell cycle activity and lack of cardiac regeneration when compared to wildtype littermate controls. Additionally, DNA synthesis and MI recovery were improved in 7-day old, non-regenerative mice when administered exogenous IL13. Overall, this proposal addresses the hypothesis that IL13 signaling enhances cardiomyocyte cell cycle activity and promotes cardiac regeneration in neonatal and adult mice. The following proposed experiments will investigate the cardio-regenerative potential of IL13 signaling both endogenously and exogenously. Specific Aim 1 will test the hypothesis that IL4Ra/IL13Ra1 depletion on cardiomyocytes will inhibit cell cycle activity and cardiac regeneration. Both in vitro and in vivo experiments will assess the endogenous role of IL13 directly on cardiomyocytes. The in vivo experiments will examine regenerative potential in a novel mouse model (IL4Rafl/fl Myh6CRE) which have a cardiomyocyte-specific depletion of IL4Ra. Aim 2 will address the hypothesis that exogenous administration of IL13 will promote cardiac regeneration and cell cycle activity in adult mice. Myocardial infarctions will be induced in 8-10 week old mice, followed by daily administration of recombinant IL13 for 4 weeks. Upon collection, cardiac function and proliferative potential will be analyzed through histology, qPCR, BrdU/EdU incorporation, and echocardiography.