Identifying novel pathways targeting endothelial-to-mesenchymal transition during heart failure

项目总结 在美国，每7人中就有1人死于心肌梗死(MI)。因为心脏几乎没有再生能力- 损伤后的恢复能力，迫切需要新的治疗方法来治疗心肌梗塞。改善肌肉-- 心肌梗死后的心脏修复需要增加对边缘灌注和刺激区域的血管供应 通过形成新的心肌细胞和支持血管系统进行心肌再生。内皮到内皮 间充质转化(EndoMT)在胚胎发育和成人心血管疾病中起着关键作用。 松弛(CVD)。虽然一些研究表明内源性MT在心力衰竭(HF)中的重要性，但我们的整体 对这一过程的了解仍处于初级阶段，部分原因是EndoMT缺乏机械性的洞察 基因受到调控，缺乏使用特定工具确定内源性MT作用的权威性研究 在成人心衰中。这项提议的目标是利用我们小组的新发现来定义 心肌梗死患者EndoMT的新microRNA(MiR)调节机制，最终用于临床翻译。就是- 心脏中TA-arrestin(β-ARR)偏向的β2-肾上腺素能受体(Beta2AR)信号诱导的心脏保护作用 这可能是β受体拮抗剂(β-受体阻滞剂)卡维地洛(CAV)的有益效果的基础。我们最近 发现CAV通过这一机制促进miR-532-5P(miR-532)的成熟， 对心脏起着至关重要的保护作用。MIR-532诱导心脏内皮细胞功能和新生血管 心肌梗死后血运重建，并抑制蛋白水解酶丝氨酸23(prss 23；内源性MT的关键启动子，以及直接和 细胞中miR-532的功能靶点)。有趣的是，miR-532的表达显著丰富在 在从缺血心肌分离的CECs中，选择性地下调CECs，这与... 表达prs23的ED。因此，更好地了解miR-532介导的心脏保护，以及 确定miR-532升高对EndoMT结局和心功能的重要性可能会导致 新的有效疗法的发展(例如。β2AR选择性的β-ARR偏向配体) 心血管病。我们的假设是Beta2AR/β-ARR介导的miR-532在内皮细胞中的成熟和功能激活 通过抑制prss 23和EndoMT，导致心肌梗死后有益的适应性重构。为了测试我们的HY- 1)确定miR-532在内皮细胞中的表达对血管内皮细胞损伤后的影响。 缺血性心脏重塑，2)阐明miR-532新的直接和功能CEC靶点prs23的作用 (3)研究β-ARR偏向激动剂对CEC和心功能的影响。 由miR-532/prs23轴滞后。这项建议是创新的，因为Beta2AR/beta-ARR/miR- 532/prss23轴在EndoMT相关心脏病理中的作用从未被研究过，并提出了EC特异性 MIR-532条件性基因敲除(KO)和PrSS23 KO小鼠模型都是全新的。这个项目也签署了- 因为Beta2AR/beta-ARR信号和miR-532/prss23轴之间的串扰可以被利用为 为研究血管内皮细胞移植介导的器官纤维化的潜在机制和治疗提供新的靶点。

PROJECT SUMMARY Myocardial infarction (MI) alone causes 1 of every 7 deaths in the United States. As the heart has little regen- erative capacity after injury, there is an urgent need for novel therapeutic approaches to MI. Improving myo- cardial repair after MI will require enhancing vascular supply to regions with marginal perfusion and stimulating myocardial regeneration through formation of new cardiomyocytes and supporting vasculature. Endothelial-to- mesenchymal transition (EndoMT) plays a key role in embryonic development and in adult cardiovascular dis- eases (CVDs). While several studies have shown the importance of EndoMT in heart failure (HF), our overall knowledge of this process remains in its infancy in part due to the lack of mechanistic insight by which EndoMT genes are regulated and the absence of definitive studies using specific tools to establish the role of EndoMT in adult HF. The goal of this proposal is to leverage novel discoveries made by our group to define the role of a new microRNA (miR) regulatory mechanism of EndoMT in MI, with an ultimate view to clinical translation. Be- ta-arrestin (beta-arr)-biased beta2-adrenergic receptor (beta2AR) signaling in the heart elicits cardioprotection and may underlie the beneficial effects of the betaAR antagonist (beta-blocker) carvedilol (Carv). We recently discovered that Carv, acting through this mechanism, promotes the maturation of miR-532-5p (miR-532), which plays a vital cardioprotective role. MiR-532 induces cardiac endothelial cell (CEC) function and neovas- cularization after MI, and represses protease serine 23 (prss23; a key initiator of EndoMT, and a direct and functional target of miR-532 in CECs). Interestingly, the expression of miR-532 is significantly enriched in CECs and selectively downregulated in CECs isolated from ischemic myocardium, which is inversely associat- ed with the expression of prss23. Thus, a greater understanding of miR-532-mediated cardiac protection, and establishing the importance of increased miR-532 to the outcome of EndoMT and cardiac function might lead to the development of novel effective therapies (eg. beta2AR-selective beta-arr biased ligands) for numerous CVDs. Our hypothesis is that beta2AR/beta-arr-mediated activation of miR-532 maturation and function in ECs results in beneficial adaptive remodeling in infarcted hearts by repressing prss23 and EndoMT. To test our hy- pothesis, we plan to pursue three aims: 1) determine the contribution of miR-532 expression in ECs to post- ischemic heart remodeling, 2) elucidate the role of prss23, a novel direct and functional CEC target of miR-532 in MI, and (3) investigate the impact of beta-arr-biased agonism of beta2AR on CEC and heart function modu- lated by the miR-532/prss23 axis. This proposal is innovative because the role of the beta2AR/beta-arr/miR- 532/prss23 axis in EndoMT-related cardiac pathologies has never been studied, and proposed EC-specific miR-532 conditional knockout (KO) and prss23 KO mouse models are entirely novel. This project is also signif- icant because the crosstalk between beta2AR/beta-arr signaling and miR-532/prss23 axis can be exploited as a novel target for studying underlying mechanisms and treatment of organ fibrosis mediated by EndoMT.