Molecular and Cellular Mechanisms of Neonatal Cardiac Development and Repair

 描述（由申请人提供）：该提案描述了一个为期五年的职业发展计划，旨在帮助候选人 Vahid Serpooshan 博士为独立调查员的职业生涯做好准备。该项目将建立在Serpooshan 博士作为生物工程科学家的多学科背景之上，他接受过心脏细胞生物学方面的培训，通过提供心脏发育背后的细胞和分子生物学方面的专业知识。拟议研究的主要目标是确定新生儿心脏发育的关键机制，可以通过工程补丁来利用这些机制来调节缺血性心脏损伤后的哺乳动物心脏发育和修复。 PI 将在斯坦福大学医学院接受 Drs. 的指导。肖恩·吴和丹尼尔·伯恩斯坦。吴博士在研究胚胎发育过程中调节心脏谱系定向的机制以及发育和疾病中心脏祖细胞的生物学方面拥有丰富的专业知识。伯恩斯坦博士是斯坦福大学小动物外科和成像设施的主任，他的研究重点是正常生理状态和疾病状态下心血管功能的调节。 我们小组和其他人的最新研究结果表明，新生哺乳动物心脏具有几种进化上保守的心肌再生机制，包括定向祖细胞的激活和/或心肌细胞增殖。然而，这些过程背后的细胞/分子机制以及它们是否可以用于修复新生儿心脏仍然难以捉摸。我们的初步数据表明，新生小鼠中存在一群 TGFβ 和 MEK 信号调节的 Nkx2.5 成肌细胞，具有增殖和分化为心肌细胞的潜力。在拟议的研究中，我将测试这样的假设：新生儿心脏中存在基于细胞的再生反应，可以通过生物工程心脏贴片输送小分子来招募该反应，以治疗心肌损伤。这项研究的结果预计将产生积极的转化影响，因为它们将为成年哺乳动物心脏的治疗干预引入一种新颖的无细胞递送方法。我的具体目标是： 目标 1：确定 Nkx2.5 成肌细胞群体及其在新生小鼠心脏中的功能。 Nkx2.5 enh-Cre/eGFP 报告小鼠模型将用于鉴定新生儿心脏中激活的 Nkx2.5 心肌祖细胞。目标 2：确定参与 Nkx2.5 成肌细胞增殖和分化的信号和途径。 TGFβ 和 MEK 信号通路的小分子调节将用于诱导新生儿 Nkx2.5 成肌细胞的扩增和心肌分化。目标 3：检查 Nkx2.5 成肌细胞和发育信号在介导缺血性心脏损伤后心脏修复中的作用。我将评估缺血性损伤后成肌细胞群体大小的变化及其对信号通路刺激的反应。

 DESCRIPTION (provided by applicant): This proposal describes a five-year career development program to prepare the candidate, Dr. Vahid Serpooshan, for a career as an independent investigator. This program will build upon Dr. Serpooshan's multidisciplinary background as a bioengineer scientist, trained in cardiac cellular biology, by providing expertise in cellular and molecular biology underlying heart development. The main goal of the proposed research is to identify the key mechanisms underlying neonatal heart development that could be exploited - via an engineered patch - to regulate mammalian heart development and repair, following ischemic heart injury. The PI will be mentored at Stanford Medical School by Drs. Sean Wu and Daniel Bernstein. Dr. Wu has extensive expertise in investigating the mechanisms regulating cardiac lineage commitment during embryonic development and the biology of cardiac progenitor cells in development and disease. Dr. Bernstein is the director of the small animal surgery and imaging facilities at the Stanford, and his research focuses on regulation of cardiovascular function in both normal physiologic states as well as in disease states. Recent findings by our group and others have demonstrated that neonatal mammalian hearts possess several evolutionarily conserved mechanisms for myocardial regeneration, including activation of committed progenitors and/or cardiomyocytes proliferation. However, the cellular/molecular mechanisms underlying these processes and whether they can be employed to repair neonatal heart remains elusive. Our preliminary data demonstrates the existence of a population of TGFβ and MEK signaling-regulated Nkx2.5+ cardiomyoblasts in neonatal mice with the potential to proliferate and differentiate into cardiomyocytes. In the proposed study, I will test the hypothesi that a cell-based regenerative response is present in the neonatal heart that can be recruited, via a bioengineered cardiac patch delivery of small molecules, for the treatment of myocardium injury. Results from this research are expected to have positive translational impact as they will introduce a novel cell-free delivery approach for therapeutic interventions in the adult mammalian heart. My specific aims are: Aim 1: Identify an Nkx2.5+ cardiomyoblast population and their function in the neonatal mouse heart. An Nkx2.5 enh-Cre/eGFP reporter mouse model will be used to identify the activated Nkx2.5 cardiomyogenic progenitors in neonatal heart. Aim 2: Determine the signal and pathways involved in Nkx2.5+ cardiomyoblasts proliferation and differentiation. Small molecule regulation of TGFβ and MEK signaling pathways will be used to induce the expansion and cardiomyogenic differentiation of the neonatal Nkx2.5+ cardiomyoblasts. Aim 3: Examine the role of Nkx2.5 cardiomyoblasts and developmental signals to mediate cardiac repair following ischemic heart injury. I will assess the changes to the cardiomyoblast population size and their response to signaling pathway stimulation following ischemic injury.