Deciphering Myofilament Modifications in Ischemic Cardiomyopathy

描述（由申请人提供）：缺血性心肌病（ICM）是美国最常见的慢性心脏病类型，也是充血性心力衰竭的常见潜在病因。尽管如此，ICM的潜在分子机制仍不清楚。此外，如果不治疗，慢性ICM的预后非常差。因此，更好地了解ICM的发病机制，并确定特异性生物标志物以早期发现和治疗ICM是非常重要的。肌节中的肌丝蛋白不仅在心肌收缩力中起重要作用，而且也是心肌收缩力的关键因素。 在心力衰竭发作和进展期间的信号接收和转导。该假说认为，心肌梗死（MI）后适应不良的心脏重塑可导致与心功能不全相关的肌丝蛋白修饰改变，并提供ICM的潜在诊断和预后生物标志物。虽然多个肌丝翻译后修饰（PTM）被认为在调节心脏功能中协同起作用，但是， 缺乏同时对肌丝蛋白进行综合分析并评估与心脏功能相关的所有协同PTM变化。在本文中，我们将采用创新的集成的“自上而下”的蛋白质质谱（MS）为基础的疾病蛋白质组学平台，同时检查从健康和患病的猪和人类心肌中提取的肌丝蛋白，并确定所有与疾病相关的肌丝修饰变化。目的1将鉴定来自MI后ICM模型的患病猪心肌的肌丝中改变的蛋白质修饰，并确定其功能后果。目的2将确定ICM患者终末期衰竭心肌的肌丝改变及其功能后果。目的3将评估新型肌丝修饰在Ca 2+介导的心肌收缩和舒张中的功能作用。机械性能（等距力和力的Ca2+敏感性）将在与蛋白质组学实验平行的皮肤心肌制备中测量。此外，我们将评估局部收缩和舒张功能，以建立特定蛋白质组学变化与体内和体外心脏功能之间的机制联系。随着该项目的完成，我们期望确定肌丝的多种功能显著改变，并了解这些改变如何协同作用，以调节MI后左心室重塑失败期间的适应不良信号。我们研究的成功将为ICM的机制提供新的见解，并将确定新的候选生物标志物，用于早期检测ICM的存在和进展。

DESCRIPTION (provided by applicant): Ischemic cardiomyopathy (ICM) is the most prevalent type of chronic heart diseases in the United States and a common underlying etiology of congestive heart failure. Nonetheless the underlying molecular mechanism of ICM remains unclear. Moreover, the prognosis of chronic ICM is very poor if left untreated. Therefore it is highly important to gain a better understanding of the disease mechanism and to identify specific biomarkers for early detection and treatment of ICM. Myofilament proteins in the sarcomeres not only play essential roles in cardiac contractility but also are critical elements in signal reception and transduction during the onset and progression to heart failure. The hypothesis is that post-myocardial infarction (MI) maladaptive cardiac remodeling can result in altered protein modifications in myofilaments that are associated with cardiac dysfunction and offer potential diagnostic and prognostic biomarkers of ICM. Although multiple myofilament post-translational modifications (PTMs) are believed to act in concert in regulating cardiac function, a comprehensive analysis of myofilament proteins simultaneously and assess all synergistic PTM changes related to cardiac function is lacking. Herein, we will employ an innovative integrated "top-down" protein mass spectrometry (MS)-based disease proteomics platform to simultaneously examine myofilament proteins extracted from healthy and diseased swine and human myocardium and identify all disease-related changes in myofilament modifications. Aim 1 will identify altered protein modifications in myofilaments from diseased swine myocardium of post-MI ICM model and determine their functional consequences. Aim 2 will determine myofilament alterations in end-stage failing human myocardium from ICM patients and their functional consequences. Aim 3 will assess the functional effects of novel myofilament modifications in Ca2+-mediated cardiac muscle contraction and relaxation. Mechanical properties (the isometric force and the Ca2+-sensitivity of the force) will be measured in skinned myocardial preparations in parallel to proteomics experiments. Furthermore, we will assess regional systolic and diastolic function to establish mechanistic links between specific proteomic changes and in vivo and ex vivo cardiac function. With the completion of this project, we expect to identify multiple functionally significant alterations in myofilaments and understand how these alterations act in concert to modulate maladaptive signaling during post-MI left ventricular remodeling to failure. The success of our research will provide new insights into the mechanisms underlying ICM and will identify new candidate biomarkers for early detection of the presence and progression of ICM.