AKAP150-TRPV4 regulation of endothelial function in obesity

抽象的。 超过三分之一的美国成年人患有肥胖症，这也是心血管疾病的潜在风险因素 包括高血压、中风和心脏病在内的疾病。因此，非常重要的是要理解 肥胖如何促进这些疾病的发展。肥胖引起的内皮功能障碍起着重要作用 在心血管异常的发展中起着至关重要的作用。在本应用程序中，我们建议解决一个 肥胖引起的内皮功能障碍的病理机制方面的主要知识空白。在……里面 阻力大小的动脉，内皮细胞钙信号机制调节内皮依赖的血管扩张。 然而，肥胖症中内皮细胞钙信号转导机制尚不清楚。我们最近发现，钙离子 通过单独的TRPV4(瞬时受体电位香草素4)通道的流入促进内皮- 依赖性血管扩张。此外，AK锚定蛋白150(AKAP150)可以锚定蛋白激酶 A和蛋白激酶C是内皮细胞内TRPV4通道活性的关键调节因子。我们假定 肥胖诱导的内皮功能障碍反映了AKAP150-TRPV4通道调节的损害 内皮功能。我们的初步数据表明，TRPV4通道功能和内皮依赖性 高脂饮食喂养的肥胖小鼠的血管扩张功能受损，血压升高。有趣的是，TRPV4 过氧亚硝酸盐抑制剂可以恢复通道功能和TRPV4介导的血管扩张，这意味着主要的 过氧亚硝酸盐在肥胖诱导的内皮功能障碍中的作用。过氧亚硝酸盐此前曾被牵连到 然而，血管疾病，过氧亚硝酸盐诱导内皮细胞改变的分子机制 功能是未知的。我们的数据支持过氧亚硝酸靶向内皮细胞AKAP150降低 TRPV4通道活性。因此，我们建议检验过氧亚硝酸盐引起的脑细胞损伤的假设。 AKAP150-TRPV4对内皮功能的调节与肥胖引起的高血压有关。以特定的目标 1，我们将检验AKAP150-TRPV4通道对内皮细胞钙信号的调节受损的假设 在肥胖方面。我们还将确定AKAP150或TRPV4通道的内皮特异性缺失 提高静息血压。在特定目标2中，我们将确定过氧亚硝酸盐如何损害AKAP150-TRPV4 调节内皮功能，并检验过氧亚硝酸盐水平升高扰乱AKAP150的假设- TRPV4对肥胖患者血管内皮功能的调节。这些研究将确定新的病理机制 以及针对肥胖症心血管异常的新治疗策略。

Abstract. More than one-third of U.S. adults suffer from obesity, which is also an underlying risk factor for cardiovascular disorders including hypertension, stroke, and heart disease. It is, therefore, extremely important to understand how obesity promotes the development of these disorders. Obesity-induced endothelial dysfunction plays a crucial role in the development of cardiovascular abnormalities. In this application, we propose to address a major gap in the knowledge about pathological mechanisms for obesity-induced endothelial dysfunction. In resistance-sized arteries, endothelial Ca2+ signaling mechanisms regulate endothelium-dependent vasodilation. However, endothelial Ca2+ signaling mechanisms remain unexplored in obesity. We recently showed that Ca2+ influx through individual TRPV4 (transient receptor potential vanilloid 4) channels promotes endothelium- dependent vasodilation. Moreover, A kinase anchoring protein 150 (AKAP150), which can anchor protein kinase A and protein kinase C, is a key regulator of TRPV4 channel activity in the endothelium. We postulate that obesity-induced endothelial dysfunction reflects an impairment of AKAP150-TRPV4 channel regulation of endothelial function. Our preliminary data demonstrate that TRPV4 channel function and endothelium-dependent vasodilation are impaired, and blood pressure is elevated in high-fat diet-fed obese mice. Interestingly, TRPV4 channel function and TRPV4-mediated vasodilation were restored by peroxynitrite inhibitors, implicating a major role for peroxynitrite in obesity-induced endothelial dysfunction. Peroxynitrite has been previously implicated in vascular disorders, however, the molecular mechanisms for peroxynitrite-induced alteration of endothelial function are not known. Our data support the concept that peroxynitrite targets endothelial AKAP150 to lower TRPV4 channel activity. Therefore, we propose to test the hypothesis that peroxynitrite-induced impairment of AKAP150-TRPV4 regulation of endothelial function contributes to obesity-induced hypertension. In Specific Aim 1, we will test the hypothesis that AKAP150-TRPV4 channel regulation of endothelial Ca2+ signaling is impaired in obesity. We will also determine whether endothelium-specific deletion of AKAP150 or TRPV4 channels elevates resting blood pressure. In Specific Aim 2, we will determine how peroxynitrite impairs AKAP150-TRPV4 regulation of endothelial function, and test the hypothesis that elevated peroxynitrite levels disrupt AKAP150- TRPV4 regulation of endothelial function in obesity. These studies will identify new pathological mechanisms for and novel therapeutic strategies against cardiovascular abnormalities in obesity.