Mechanisms of myocardial regeneration mediated by Nkx2.5 in zebrafish

项目摘要 由于损伤心肌再生反应的能力有限， 发病率和死亡率的主要原因。冠状动脉疾病导致心肌梗死， 纤维化瘢痕、不良重塑和心力衰竭。与成年小鼠和人类相比，新生小鼠 成年斑马鱼保留了心肌细胞去分化和增殖的能力， 刺激损伤后的心脏再生。破译人类共有的基本转录网络 在发展和再生将燃料我们唤醒内源性修复机制的能力。在斑马鱼中， 心脏发生所必需的胚胎心脏转录因子，如Nkx2.5， 损伤以刺激心肌细胞产生。我们的初步研究表明，Fibulin 5，一种细胞外基质， (ECM)在Nkx2.5下游起作用的糖蛋白在受损的心脏中上调。此外，我们显示 纤维蛋白功能丧失鱼表现出受损的再生能力和在迁移和组织中的关键作用， 弹性在这个提议中，我们将测试Nkx2.5的激活是产生ECM所必需的假设。 环境包括主要的促再生蛋白质，如Fibulin 5，可以利用它来增加细胞再生。 为患者提供基础治疗。在目标1中，我们将阐明Nkx2.5引导效应子的无数机制 使用基于质谱的蛋白质组学方法介导ECM元件的沉积和重塑， 战略布局在目标2中，我们假设Fibulin 5调节TGF-β信号传导以促进心外膜侵袭， 滴定组织硬度。我们将剖析经典和非经典的TGF-β途径，以确定关键的 Fibulin 5下游的信号传导器。使用心脏切片的时间推移成像，我们将探测 当它们深入伤口时，心外膜和心肌细胞在真实的时间内的交织运动。 我们将受益于原子力显微镜测量再生心肌的弹性模量， 需要Fibulin 5来保持可延展的微环境以促进迁移。在目标3中，我们 研究的前提是，Fibulin 5是再生ECM的重要组成部分，有可能增强 通过评估体外hiPSC-CM的移动性和体内宿主-移植物整合来消除瘢痕。一起我们 我预计我们的工作将启动一个新的范例，强调胚胎ECM的重要性 Nkx 2 -5下游的纤蛋白5等组分促进心外膜和心肌细胞迁移， 组织弹性，以增强患者的治疗策略。

PROJECT SUMMARY Due to the limited ability to mount a regenerative response in injured myocardium, cardiac dysfunction remains a key cause of morbidity and mortality. Coronary artery disease leads to myocardial infarction which results in fibrotic scarring, adverse remodeling, and heart failure. In contrast to adult mice and humans, neonatal mice and adult zebrafish retain the ability to undergo cardiomyocyte dedifferentiation and proliferation, ultimately stimulating cardiac regeneration following injury. Deciphering the fundamental transcriptional networks shared in development and regeneration will fuel our ability to awaken endogenous reparative mechanisms. In zebrafish, embryonic cardiac transcriptional factors necessary for cardiogenesis, such as Nkx2.5, are galvanized following injury to stimulate cardiomyocyte production. Our preliminary studies reveal that Fibulin 5, an extracellular matrix (ECM) glycoprotein functioning downstream of Nkx2.5, is upregulated in the injured heart. Moreover, we show that fibulin loss-of-function fish exhibit impaired regenerative capacity and crucial roles in migration and tissue elasticity. In this proposal, we will test the hypothesis that activation of Nkx2.5 is necessary to produce an ECM milieu comprise of cardinal pro-regenerative proteins such as Fibulin 5 that can be harnessed to augment cell- based therapies for patients. In Aim 1, we will elucidate the myriad mechanisms by which Nkx2.5 directs effectors to mediate deposition and remodeling of ECM elements employing mass spectrometry-based proteomic strategies. In Aim 2, we postulate that Fibulin 5 modulates TGF-β signaling to promote epicardial invasion and titrate tissue stiffness. We will dissect both the canonical and non-canonical TGF-β pathways to identify the key signal transducers downstream of Fibulin 5. Using time lapse imaging of cardiac slices, we will probe the intertwined movements of epicardial and myocardial cells in real time as they penetrate deep into the wound. We will benefit from atomic force microscopy to measure elastic modulus in regenerating myocardium to uncover the requirement of Fibulin 5 in preserving a malleable microenvironment to promote migration. In Aim 3, we will investigate the premise that Fibulin 5 is a vital component of the regenerative ECM with potential to enhance scar resolution by evaluating hiPSC-CMs mobility in vitro and host-graft integration in vivo. Together, we anticipate that our proposed work will launch a novel paradigm highlighting the importance of embryonic ECM components such as Fibulin 5 downstream of Nkx2-5 in promoting epicardial and cardiomyocyte migration and tissue elasticity to enhance therapeutic strategies for patients.