MOLECULAR POLARIZATION IN DYSSYNCHRONOUS HEARTS AND CRT

这个子项目的重点是定义的影响和机制，心脏不同步与或不与潜在的心力衰竭诱导局部分子和细胞透壁异常。该项目源于我们最近的发现，即衰竭心脏的不同步导致与钙处理，肥大信号和电传导有关的蛋白质表达的显着局部变化。这些变化特别集中在后期激活区域的内皮层，该区域预计具有最高水平的壁应力。相邻的中间心外膜组织显示的表达更类似于在对侧壁（外膜层和内膜层）中观察到的表达。这突出了局部化的透壁分子极化，可以作为为什么不同步是心力衰竭患者的主要风险的重要基质。除了对衰竭中不同步的心室分子和细胞效应进行更全面的分析外，该子项目还将通过心脏复律来测试这些变化的可逆性。有三个具体目标。第一个目标将确定在不同步心脏中触发的信号级联，阐明其对晚期（高应激）激活心肌中内皮细胞层的特异性，并确定共存扩张性心力衰竭的协同作用。采用两种主要策略：候选蛋白/基因的特异性检测 涉及生长、重塑和肌细胞钙处理，以及更广泛的肌细胞亚蛋白质组（胞质、肌浆网、间隙连接）和转录组（犬阵列芯片）分析。第二个目标是将这些分子研究结果与来自内皮层和中壁层的早期与晚期激活区域的心肌细胞中不同步的细胞功能和钙处理影响的直接分析相结合。第三个目的是测试由随后的心脏双心室起搏不同步引起的分子和细胞异常的可逆性。这些研究将提供这种可逆性的第一个测试，并将分子和细胞水平的变化整合到整个器官水平。

This subproject focuses on defining the influence and mechanisms whereby cardiac dyssynchrony with and without underlying cardiac failure induces local molecular and cellular transmural abnormalities. This project stems from our recent discovery that dyssynchrony in a failing heart results in striking localized changes in the expression of proteins involved with calcium handling, hypertrophic signaling, and electrical conduction. These changes are particularly concentrated in the endocardial layer of the late-activated territory, the region predicted to have the highest level of wall stress. Neighboring mid-epicardial tissue displays expression more akin to that observed in the opposing wall (both epi and endo layers). This highlights a localized transmural molecular polarization that can serve as an important substrate for why dyssynchrony is a major risk in heart failure patients. In addition to providing a more comprehensive analysis of the ventricular molecular and cellular effects from dyssynchrony in failure, this subproject will test the reversibility of these changes by means of cardiac resynchronization. There are three specific aims. The first aim will identify signaling cascades triggered in the dyssynchronous heart, clarify their specificity to endocardial layers in late (high stress)-activated myocardium, and determine the synergistic role of co-existing dilated cardiac failure. Two major strategies are used: specific testing of candidate proteins/genes involved with growth, remodeling, and myocyte calcium handing, and a broader analysis of myocyte sub-proteome (cytosolic, sarcomplasmic reticulum, gap junction) and transcriptome (canine array chip). The second aim will integrate these molecular findings with direct analysis of the cellular functional and calcium handling impact of dyssynchrony in cardiomyocytes derived from early versus late activated territories from both endocardial and mid-wall layers. The third aim tests the reversibility of molecular and cellular abnormalities induced by dyssynchrony by a subsequent period of cardiac bi-ventricular resynchronization. These studies will provide the first test of such reversibility, and integrate changes at molecular and cellular levels to at the whole organ level.