Regulation of cardiac power output in health and disease

描述(申请人提供)：心脏周期是一个严格调节的过程，心脏在收缩时产生能量，然后在舒张期放松。这个循环的功能障碍，就像心肌病患者一样，可能会导致心力衰竭和心律失常。家族性心肌病在1：500的人群中发现，主要是由参与肌肉收缩的肌节蛋白突变引起的。有人提出，这些突变会影响心脏周期的调节以及心脏产生有效地将血液输送到身体所需的力量和功率的能力，从而导致心脏组织的重组和最终的心力衰竭。尽管有许多出色的实验，但人们并不清楚分子水平上的突变如何导致细胞收缩能力和组织结构的变化。这项研究将有助于弥合我们对疾病发病机制的认识上的这一重大差距。通过结合单分子、整体动力学、干细胞工程和组织工程技术，我们的方法将使我们能够了解与心肌病突变相关的收缩能力的分子变化如何导致人类心脏组织的力和功率输出的变化。在K99部分的拨款中，我们将开发(1)一种新型的单分子体外试验，使我们能够模拟心脏的工作条件；(2)在微型机电设备中，我们将开发一种新的单分子体外分析方法，使我们能够检查人类心脏组织的收缩和结构特性。我们将使用分析方法来研究在分子、细胞和组织水平上调节健康心脏的力和功率输出的因素。重要的是，资助的K99部分中开发的技术和方法将补充PI目前的技能集，使他能够建立一个创新的研究计划。在拨款的R00部分，我们将应用这些新开发的技术来研究与人类心肌病相关的突变如何在分子、细胞和组织水平上导致力和功率输出的变化。这种多层次的方法将使我们对疾病的发病机制有一个前所未有的了解。此外，在资助期间开发的技术和方法应该会为未来的研究开辟几个新的途径，因为PI将过渡到完全独立的科学家。

DESCRIPTION (provided by applicant): The cardiac cycle is a tightly regulated process in which the heart generates power during systole and then relaxes during diastole. Dysfunction of this cycle, as seen in patients with cardiomyopathies, can lead to heart failure and arrhythmias. Familial cardiomyopathies, found in 1:500 members of the population, are caused primarily by mutation of sarcomeric proteins involved in muscle contraction. It has been proposed that these mutations affect the regulation of the cardiac cycle and the ability of the heart to generate the force and power necessary to effectively pump blood to the body, leading to restructuring of the heart tissue and eventual heart failure. Despite many elegant experiments, it is not well understood how mutations on the molecular scale lead to changes in cellular contractility and tissue organization. This research will help to bridge this major gap in our understanding of the disease pathogenesis. By combining single molecule, ensemble kinetic, stem cell engineering, and tissue engineering techniques, our approach will allow us to understand how molecular changes in contractility associated with cardiomyopathy mutations lead to alterations in force and power output in human cardiac tissue. During the K99 portion of the grant, we will develop (1) a novel single-molecule in vitro assay that will enable us to mimic working conditions in the heart and (2) human cardiac microtissues in microelectromechanical devices that will enable us to examine the contractile and structural properties of human cardiac tissue. We will use assays to study the factors that regulate force and power output at the molecular, cellular, and tissue levels in healthy hearts. Importantly, the techniques and approaches developed in the K99 portion of the grant will complement the PI's current skill set, enabling him to establish an innovative research program. During the R00 portion of the grant, we will apply these newly developed technologies to studying how mutations associated with human cardiomyopathies lead to alterations in force and power output at the molecular, cellular, and tissue levels. This multi-tiered approach will give us an unprecedented understanding of the disease pathogenesis. Moreover, the techniques and approaches developed during the funding period should open several new avenues for future studies as the PI transitions to being a fully- independent scientist.