TRPC Channels in the Metabolic Syndrome

描述(由申请人提供)：典型色氨酸通道(TRPC)在血管平滑肌细胞的质膜上形成储存和受体操作的钙离子通透通道。TRPC参与调节血管张力和平滑肌细胞增殖。该提案将确定TRPC通道在与代谢综合征(METS)相关的冠状动脉重构过程中的分子作用。METS的特点是中心性肥胖、血浆胆固醇和空腹血糖升高、高血压、胰岛素抵抗和动脉粥样硬化。在美国成年人中，甲型肝炎的患病率为24%。在这个研究项目中，我们将利用Mets Ossabaw猪模型，该模型显示了Mets的所有特征，包括过度活跃的肾素-血管紧张素-醛固酮系统(RAAS)。我们发现TRPC1和TRPC6通道在表现为动脉粥样硬化和高收缩的蛋氨酸Ossabaw猪冠状动脉中的表达水平显着升高。新鲜分离的Mets冠脉平滑肌细胞有较高的钙离子内流和较大的钙通道通道电流。由于血管紧张素II和醛固酮是TRPC表达的正调节因子，我们推测，在蛋氨酸中，过度活跃的RAAS上调了TRPC1和TRPC6的表达，从而促进了冠状动脉平滑肌细胞的增殖和冠状动脉的过度收缩。本研究的具体目标如下：1)确定TRPC在甲硫氨酸相关的冠状动脉平滑肌细胞重塑过程中的分子表达如何变化；2)确定TRPC在对照和Mets冠状动脉平滑肌细胞内源性储存和受体激活的钙内流/电流中的作用；3)确定内源性TRPC通道的功能表达是否直接受到RAAS组分血管紧张素II和Aldo的调节；4)确定在体内，TRPC的靶向性下调是否减缓了Mets猪的动脉粥样硬化进展，降低了冠状动脉的超缩性。在这项研究计划中，我们将使用分子生物学、生化、电生理和荧光成像方法以及血管内超声、等长张力和冠状动脉环腔面积测量。此外，还将使用冠状动脉靶向递送方法将shRNAs和cDNAs构建体部署到冠脉壁中。重要的是，我们将确定TRPC1和TRPC6在蛋氨酸相关的天然动脉粥样硬化进展中的不同作用。

DESCRIPTION (provided by applicant): Canonical TRP channels (TRPC) form store- and receptor-operated Ca2+-permeable channels in the plasma membrane of vascular smooth muscle cells. TRPCs have been implicated in regulating vascular tone and smooth muscle cell proliferation. This proposal will define the molecular roles of TRPC channels during coronary artery remodeling associated with metabolic syndrome (MetS). MetS is characterized by central obesity, elevated plasma cholesterol and fasting glucose, hypertension, insulin resistance, and atherosclerosis. The prevalence of MetS among adults in the USA is 24%. In this research program, we will utilize the MetS Ossabaw pig model that exhibits all of the characteristics of MetS, including the overactive renin-angiotensin- aldosterone system (RAAS). We demonstrated that the expression levels of TRPC1 and TRPC6 channels are markedly elevated in MetS Ossabaw pig coronary arteries exhibiting atherosclerosis and hypercontractility. Consistently, freshly isolated MetS coronary artery smooth muscle cells had elevated store-/receptor-operated Ca2+ influx and large store-/receptor-operated TRPC-like currents. Since angiotensin II and aldosterone are positive regulators of TRPC expression, we hypothesize that, in MetS, the overactive RAAS upregulates TRPC1 and TRPC6 expression, which drives increased coronary smooth muscle cell proliferation and coronary artery hypercontractility. The following Specific Aims will be pursued: 1) To determine how the molecular expression of TRPCs is altered during the MetS-associated remodeling of coronary artery smooth muscle cells; 2) To define the contribution of TRPCs to endogenous store- and receptor-activated Ca2+ influx/currents in control and MetS coronary artery smooth muscle cells; 3) To determine whether the functional expression of endogenous TRPC channels is directly regulated by RAAS components, angiotensin II and Aldo, in coronary artery smooth muscle cells; 4) To determine whether the in vivo, coronary artery targeted down- regulation of TRPCs slows atheroma progression and decreases coronary artery hypercontractility in MetS pigs. During this research program, we will use molecular biological, biochemical, electrophysiological, and fluorescence imaging approaches as well as intravascular ultrasound, isometric tension and coronary artery ring lumen area measurements. Additionally, a coronary artery targeted delivery approach will be employed to deploy shRNAs and cDNA constructs into the coronary artery wall in vivo. Importantly, we will determine the distinct roles of TRPC1 and TRPC6 during MetS-associated NATIVE atherosclerosis progression.