Connexin 43 gap junction dynamics in the diabetic heart

所提供的空间。 糖尿病患者发生致命性心律失常的风险增加，心肌损伤后恢复率下降，心肌病导致的心功能不全与动脉硬化和高血压无关。 导致心脏功能不全的机制尚不清楚，然而，最近的研究表明心脏缝隙连接重构参与其中。小带闭锁蛋白-1(ZO-1)与连接蛋白43(Cx43)结合，这种相互作用在缝隙连接重塑中起重要作用。推测这两种蛋白的相互作用是导致包括脑室在内的致命性下游生理后果的主要因素。 糖尿病心脏的功能障碍和心律失常。这一假设将通过以下目标进行检验： 1.确定糖尿病啮齿动物模型中Cx43缝隙连接的大小和细胞分布是否以与ZO-1 Cx43结合的变化相关的方式发生改变。 1B.确定糖尿病啮齿动物模型的舒张期功能障碍和对诱发性心律失常的易感性与心室ZO-1 Cx43结合的变化之间的关联程度。 2a.确定高血糖诱导的Cx43缝隙连接大小、细胞分布和磷酸化的变化与ZO-1结合的Cx43在体外的相关性。 2B。确定高血糖诱导的Cx43缝隙连接重构是否被一种膜永久性多肽(ACT-1)正常化，该多肽旨在体外抑制ZO-1与Cx43的相互作用。 将使用几种方法，包括免疫共聚焦共定位分析、Western blotting、FRET(荧光共振能量转移)、免疫沉淀、蛋白质-蛋白质交联和电子显微镜。此外，还将使用心电图术、超声心动图和荧光电压敏感染料的光学测绘来评估心脏功能。此外，在AIM 2中，活细胞成像 还将在高糖和低糖条件下进行Cx43和ZO-1的荧光标记构建。 在美国，80%的糖尿病患者死于心血管并发症，每年导致超过50000人死亡。该项目将更好地了解糖尿病心脏病的基本机制，并可能导致超越血压和血糖控制的新疗法。

SPACE PROVIDED. Diabetic patients exhibit an increased risk of fatal arrhythmias, decreased recovery after a myocardial insult, and a cardiomyopathy leading to ventricular dysfunction independent of arteriolosclerosis and hypertension. The mechanism leading to cardiac dysfunction is not known, however, recent studies have suggested involvement of cardiac gap junction remodeling. Zonula occludens-1 (ZO-1) binds Connexin 43 (Cx43), and this interaction is important for gapjunction remodeling. It is hypothesized that the interaction of these two proteins is a major contributor to the lethal downstream physiological consequences including ventricular dysfunction and arrhythmias in the diabetic heart. This hypothesis will be tested through the following aims: 1 A. Determine whether Cx43 gap junction size and cellular distribution are altered in the ventricle of rodent models of diabetes in a manner that correlates with changes in ZO-1 Cx43 binding. 1B. Determine the extent to which diastolic dysfunction and susceptibility to inducible arrhythmia correlate with changes in ZO-1 Cx43 binding in the ventricle of rodent models of diabetes. 2A. Determine the extent to which hyperglycemia induced changes in Cx43 gap junction size, cellular distribution, and phosphorylation correlate with ZO-1 binding Cx43 in vitro. 2B. Determine if hyperglycemia induced remodeling of Cx43 gap junctions are normalized by a membrane permanent peptide (ACT-1) designed to inhibit the interaction of ZO-1 with Cx43 in vitro. Several approaches will be used including immuno-confocal colocalization analysis, Western blotting, FRET (fluorescent resonance energy transfer), immunoprecipitation, protein-protein crosslinking, and electron microscopy. In addition cardiac function will be assessed using electrocardiography, echocardiography and optical mapping of fluorescent voltage sensitive dyes. Additionally in Aim 2, live cell imaging of fluorescently tagged constructs of Cx43 and ZO-1 in high and low glucose conditions will also be performed. Eighty percent of diabetics in the US die of cardiovascular complications resulting in over 50000 deaths/year. This project will provide a better understanding of the fundamental mechanism of diabetic heart disease and may lead to new treatments beyond blood pressure and sugar control.