Defining the Cellular Morphogenic Behaviors that Shape the Developing Heart

项目摘要 先天性心脏病（CHD）是最普遍和最具破坏性的先天性疾病之一， 在近1%的活产婴儿中，并为受影响的个体造成改变生命的并发症。CHD的起源 在胚胎发育的早期心脏形成的时候。以前的研究表明，最早的心脏 祖细胞在原肠胚形成过程中被指定，然后迁移到胚胎的前部以形成细胞。 短暂的心脏新月形和随后的线性心管。此后，心管经历右向 以适当地定位心管的节段并产生四室成人心脏。虽然 已经描述了促进心脏发育的大体形态学过程， 驱动这些过程的行为仍然未知。 这项工作的主要目标是精确地定义细胞形态发生行为，以及它们的 基因组决定因素，这些决定因素塑造了发育中的心脏，以便更好地了解CHD是如何发生的， 这些行为都被错误地管制了。这将通过三个具体目标来实现： 通过对心脏祖细胞进行活体成像，了解心管形成的形态发生行为 ii）确定关键心脏转录因子Tbx 5和Tbx 5在小鼠胚胎心脏发生中的作用; Mef 2c在心管形态发生中的作用--通过量化在通往不适当心管的途中被破坏的细胞行为 iii）鉴定心管形态发生的基因组决定因素， 对野生型、Tbx 5-null和Mef 2c-null进行基因表达和染色质可及性的多组学分析。 无效胚胎本次博士后培训将在领导者Benoit Bruneau博士的监督下进行 在心脏生物学和胚胎学领域，在格莱斯顿研究所，一个世界著名的研究中心， 对学员职业发展的杰出承诺。布鲁诺实验室和格莱斯顿 核心设施将提供所有必要的资源和专业知识，使成功完成 建议的工作。高分辨率活胚胎成像和单细胞基因组分析的结合将 识别构建心脏所需的物理过程以及转录程序 在时空上调节这些细胞的行为。这些信息将促进我们对 哺乳动物心脏发生超越目前的单基因范式，并将提供重要的见解， 先天性心脏病是如何在胚胎发育过程中出现的

PROJECT SUMMARY Congenital heart defects (CHDs) are among the most prevalent and devastating congenital disorders, occurring in nearly 1% of live births and creating live-changing complications for affected individuals. The origins of CHDs lie early in embryogenesis as the heart takes shape. Previous studies have demonstrated that the earliest cardiac progenitor cells are specified during gastrulation, and then migrate to the anterior of the embryo to form the transient cardiac crescent and subsequent linear heart tube. Thereafter, the heart tube undergoes right-ward looping to properly position the segments of the heart tube and produce the four-chambered adult heart. Although the gross morphological processes that facilitate heart development have been described, the specific cellular behaviors that drive these processes remain unknown. The primary objective of this proposed work is to precisely define the cellular morphogenic behaviors, and their genomic determinants, that shape the developing heart in order to better understand how CHDs arise when these behaviors are mis-regulated. This will be achieved through three specific aims: i) Defining the cellular morphogenic behaviors that underlie heart tube formation by conducting live imaging of cardiac progenitors during cardiogenesis in mouse embryos; ii) Determining the role of key cardiac transcription factors Tbx5 and Mef2c in heart tube morphogenesis by quantifying disrupted cellular behaviors en route to improper heart tube formation in mutant embryos; iii) Identifying the genomic determinants of heart tube morphogenesis by performing multiomic analysis of gene expression and chromatin accessibility for wild type, Tbx5-null, and Mef2c- null embryos. This postdoctoral training will be conducted under the supervision of Dr. Benoit Bruneau, a leader in the fields of cardiac biology and embryology, at Gladstone Institutes, a world-renowned research center with an outstanding commitment to the career development of its trainees. The Bruneau laboratory and the Gladstone core facilities will provide all the necessary resources and expertise required to enable successful completion of the proposed work. The combination of high-resolution live embryo imaging and single cell genomic analysis will identify both the physical processes that are required to build the heart, as well as the transcriptional programs that spatiotemporally regulate those cellular behaviors. This information will advance our understanding of mammalian cardiogenesis beyond the current single-gene paradigm, and will provide important insights to inform how CHDs arise during embryogenesis.