Biomechanics of early mammalian cardiogenesis

项目摘要 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）衰竭是出生缺陷的主要原因- 婴儿相关死亡。众所周知，生物力学刺激是重要的 CV发展的调节剂。因此，定义机械因素如何集成 通过遗传途径协调哺乳动物的心管功能和形态发生 对了解冠心病和心力衰竭至关重要。这些信息也将 在治疗/预防CHD的新治疗干预策略中， 为此，小鼠模型是研究人类的一个很好的系统。 先天性缺陷然而，由于哺乳动物发育的内在性质， 心脏生物力学的分析具有挑战性。 通过上一轮的资助，我们建立了一套创新的光学 相干断层扫描（OCT）方法用于实时、高分辨率3D成像， 小鼠胚胎CV动力学的定量评估。这些技术 应用于E8.5至E10.5小鼠心脏泵送机制的分析， 模拟人类CHD的突变表型的表征。因此，我们处于一个 独特的位置，研究如何机械刺激的心脏动力学和血液流动 与心脏分化早期的分子/遗传变化有关， 小鼠胚胎 虽然多项研究表明，心脏收缩，血流和僵硬度， 影响简历的发展，由于这些因素的相互依赖性，他们的个人 角色不明。本提案的目的是确定心脏的不同作用， 收缩和流动诱导的剪切应力在调节机械稳态中的作用 （硬度）和细胞命运决定。这些实验将专门针对 这些因素之间的背景依赖性相互作用，可能会在心脏 具有不同职能作用的区域，例如积极收缩区域与 被动收缩流出道（OFT）。 科学假设，科学严谨性和相关的生物变量：这 该提案将填补早期哺乳动物心脏发育领域的重大空白 并定义心力在维持机械稳态和细胞内环境中的作用， 分化这些信息将有助于更好地了解、预防和 治疗人类CHD和胚胎心脏衰竭。拟定研究 得到了有力的初步数据支持。我们仔细阐述了 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， 在提案中提出。提供了广泛的细节，以确保初步和 这些实验可以在其他实验室进行。

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.