Therapeutic Mechanisms of Cardiac Progenitors in Ischemic Cardiomyopathy

缺血性心脏病是世界范围内的主要死亡原因。由于再生能力有限， 在心肌损伤后的人类心脏中，基于干细胞的疗法，包括最近的cKit+细胞疗法， 成为改善心脏修复和功能的一种有前途的方法。临床和临床前数据 表明cKit+细胞移植的益处包括改善心脏功能和心肌质量。 然而，cKit+ CPCs分化为心肌细胞作为心脏修复的重要模式的能力是不确定的。 争议我们小组发表的数据已经确定了干细胞因子（SCF）的有益作用， cKit的配体，在大鼠和猪中改善cKit+细胞的丰度、血管生成和心功能 缺血性心肌病模型。此外，我们的初步数据表明，分泌的旁分泌因子， 特别是膜结合的外泌体，可以介导大部分促血管生成的旁分泌活性， SCF处理的cKit+细胞。我们的中心假设是，动员一个异质群体， 使用受体酪氨酸cKit配体干细胞因子（SCF）的基因转移的内源性CPC可以 通过旁分泌促进心肌损伤后的心脏组织修复。 我们将使用MI模型检验SCF诱导CPC募集的充要条件 目的是评价SCF诱导的表达cKit、PW 1和PDGFR β的CPC在猪心力衰竭中的作用。 心肌修复、再生和功能恢复。我们将检验cKit、PW 1和 PDGFR β祖细胞足以用于SCF诱导的心脏修复，通过使用 SCF modRNA。我们将检验cKit、PW 1和PDGFR β祖细胞对于肿瘤的发生是必需的这一假设。 使用shRNA介导的cKit、PDGFR β和PW 1敲低通过功能丧失进行的心脏修复实验 受体。RNA将在MI后一周通过临床相关的冠状动脉内途径和动物递送 将评估存活率、心脏重塑、心脏功能、细胞特异性增殖和分化 以及相关的分子机制。 我们将确定cKit+ CPC的旁分泌在SCF诱导的心脏修复中的作用。我们 初步数据表明，外泌体，而不是来自MI后猪的外泌体耗尽部分cKit- 分泌体具有促血管生成活性。利用外来体研究的特定专业知识，我们将确定 响应SCF的cKit+外泌体的miRNA表达。此外，我们将研究功能 cKit+外泌体诱导心肌细胞增殖和收缩功能的机制， 血管生成的内皮细胞在体外。最后，我们将确定cKit外泌体在以下疾病中的治疗益处： 一个心力衰竭的猪模型

Ischemic heart disease is a leading cause of death worldwide. Given the limited regenerative capacity of the human heart following myocardial injury, stem cell-based therapies, including the recent cKit+ cell therapy have emerged as a promising approach for improving cardiac repair and function. Clinical and preclinical data suggests that benefits of cKit+ cell transplantation include improved cardiac function and myocardial mass. However, the ability of cKit+ CPCs to differentiate into cardiomyocytes as a significant mode of cardiac repair is controversial. Published data from our group has established the beneficial effects of stem cell factor (SCF), the ligand for cKit, in improving the abundance of cKit+ cells, angiogenesis and cardiac function in both rat and pig models of ischemic cardiomyopathy. Further, our preliminary data suggest that secreted paracrine factors, particularly the membrane-bound exosomes, may mediate most of the pro-angiogenic paracrine activity of the SCF-treated cKit+ cell. Our central hypothesis is that mobilization of a heterogeneous group of endogenous CPCs using gene transfer for the receptor tyrosine cKit ligand stem cell factor (SCF) can enhance cardiac tissue repair following myocardial injury via their paracrine secretion. We will test the necessary and sufficient conditions of SCF-induced CPC recruitment using the MI model of heart failure in swine to evaluate the roles of SCF-induced cKit, PW1 and PDGFR expressing CPCs in myocardial repair, regeneration and restoration of function. We will test the hypothesis that cKit, PW1 and PDGFR progenitor cells are sufficient for SCF induced cardiac repair by gain of function experiments using SCF modRNA. We will test the hypothesis that cKit, PW1 and PDGFR progenitor cells are necessary for cardiac repair by loss of function experiments using shRNA-mediated knockdown of cKit, PDGFR and PW1 receptors. RNAs will be delivered one-week post-MI by the clinically relevant intracoronary route and animals will be evaluated for survival, cardiac remodeling, cardiac function, cell-specific proliferation and differentiation and the molecular mechanisms involved. We will determine the role of paracrine secretion from cKit+ CPCs in SCF-induced cardiac repair. Our preliminary data suggest that exosomes, and not the exosomes-depleted fraction from swine post-MI cKit- secretome have pro-angiogenic activity. Using specific expertise for exosomes research, we will identify the miRNA expression of cKit+ exosomes in response to SCF. In addition, we will investigate the functional mechanisms of cKit+ exosomes-induced proliferation and contractile function of cardiomyocytes and angiogenesis of endothelial cells in vitro. Finally, we will determine the therapeutic benefits of cKit exosomes in a swine model of heart failure.