Biomechanics of early mammalian cardiogenesis

项目总结 人类先天性心脏病(CHD)非常常见，发生在近1%的 活产。此外，心血管(CV)衰竭是导致出生缺陷的主要原因- 婴儿的相关死亡。众所周知，生物力学刺激是很重要的。 简历发展的监管者。因此，定义机械因素是如何集成的 具有协调哺乳动物心管功能和形态发生的遗传途径 对于了解冠心病和心力衰竭至关重要。这类信息还将 在治疗/预防冠心病的新治疗干预措施的战略中有很大的考虑因素。 为此，小鼠模型是研究人类的一个很好的系统 先天缺陷。然而，由于哺乳动物发育的内在本质， 心脏生物力学的分析是具有挑战性的。 通过前一个周期的这笔赠款，我们建立了一套创新的光学 相干层析成像(OCT)方法用于实时、高分辨率3D成像和 小鼠胚胎CV动态的定量评估。这些技术是 应用于分析E8.5~E10.5小鼠心脏和心脏的泵血机制 模拟人类先天性心脏病的突变表型的特征。因此，我们正处于一个 独特的位置研究机械刺激对心脏动力学和血流的影响 与活体心脏早期分化过程中的分子/遗传变化有关 小鼠胚胎。 虽然多项研究表明，心脏收缩、血流和僵硬 影响简历发展，由于这些因素的相互依存，他们的个人 角色是未知的。这项提议的目标是定义心脏的不同作用 收缩和流致剪应力在调节机械动态平衡中的作用 (刚性)和体内细胞命运的决定。这些实验将具体解决 这些因素之间的上下文相关相互作用，这些因素可能在不同的心脏 具有不同职能角色的区域，例如在积极收缩区域与 被动收缩流出道(OFT) 科学前提、科学严谨和相关的生物变量：这 该提案将填补哺乳动物早期心脏发育领域的一个重大空白 并确定了心力在维持机械动态平衡和细胞 差异化。这些信息将有助于更好地了解、预防和 人类先天性心脏病和胚胎心力衰竭的治疗。建议的研究是 受强劲的初步数据支撑。我们仔细地阐述了 将使用的实验动物，这些动物的精确基因组成，以及 选择模型的理由。性别作为一个生物变量被认为是 提案中涉及的问题。提供了广泛的细节，以确保初步和 拟议的实验可以在其他实验室复制。

PROJECT SUMMARY Human congenital heart defects (CHD) are very common, occurring in nearly 1% of live births. Moreover, cardiovascular (CV) failures are the leading cause of birth defect- related deaths in infants. It is well established that biomechanical stimuli are important regulators of CV development. Thus, defining how mechanical factors are integrated with genetic pathways to coordinate mammalian heart tube function and morphogenesis is critically important for understanding CHD and heart failure. Such information will also factor heavily into strategies for new therapeutic interventions to treat/prevent CHD. Toward that end, the mouse model is an excellent system in which to study human congenital defects. However, due to the internal nature of mammalian development, analysis of heart biomechanics is challenging. Through the previous cycle of this grant, we established a set of innovative optical coherence tomography (OCT) approaches for live, high-resolution 3D imaging and quantitative assessment of mouse embryo CV dynamics. These techniques were applied to analysis of the pumping mechanism of the E8.5 to E10.5 mouse heart and characterization of mutant phenotypes mimicking human CHDs. Therefore, we are in a unique position to investigate how mechanical stimuli of cardiodynamics and blood flow are linked to molecular/genetic changes during early cardiac differentiation in living mouse embryos. While multiple studies suggest that cardiac contraction, blood flow and stiffness each influence CV development, due to the interdependence of these factors, their individual roles are unknown. The goal of this proposal is to define the differential role of cardiac contraction and flow-induced shear stress in regulating mechanical homeostasis (stiffness) and cell fate decisions in vivo. These experiments will specifically address the context-dependent interplay between these factors, which likely vary between cardiac regions with different functional roles, such as in actively contracting regions versus the passively contracting outflow tract (OFT). Scientific Premise, Scientific Rigor, and Relevant Biological Variables: This proposal will fill a significant gap in the field of early mammalian cardiac development and define the role of cardiac forces in maintaining mechanical homeostasis and cell differentiation. This information will lead to a better understanding, prevention and treatment of CHD and embryonic cardiac failures in humans. The proposed study is supported by strong preliminary data. We carefully articulated the number of experimental animals to be used, the precise genetic makeup of these animals, and the rationale for the choice of the models. Sex as a biological variable is considered and addressed in the proposal. Extensive details are provided to ensure that preliminary and proposed experiments can be replicated in other laboratories.