Cav-1.TRPV4 regulation of endothelial function in small pulmonary arteries

摘要 肺动脉高压(PAH)是一种肺血管疾病，死亡率高达 确诊三年后45%。PAH通常与内皮依赖性血管扩张功能的丧失有关， 长期以来，它被认为是多环芳烃发展的主要贡献者。然而，潜在的 PAH中内皮依赖性血管扩张功能丧失的机制尚不清楚，尤其是在自然发病的 来自控制肺动脉压的小肺动脉(PAS)的内皮细胞。我们最近展示了 内皮TRPV4(瞬时受体电位香草素4)通道是内皮的关键调节因子。 PAS中的依赖性血管扩张。在本应用中，我们提供了内皮TRPV4的新的初步数据 通道调节静息状态下的肺动脉压(PAP)，在PAH中受损。此外，我们证明了 支架蛋白小窝蛋白-1为蛋白激酶C(PKC)依赖的调控提供了一个信号平台 TRPV4通道，一种在PAH中有缺陷的机制。有趣的是，两种不同的过氧亚硝酸盐清除剂 PAH内皮细胞TRPV4通道活性恢复，提示过氧亚硝酸盐可能是 TRPV4通道功能障碍。此外，外源性过氧亚硝酸盐还可损伤小窝蛋白-1·PKC 内皮细胞TRPV4通道功能的调节。因此，我们假设过氧亚硝酸盐诱导 小窝蛋白-1·蛋白激酶C对TRPV4通道功能的调节受损导致内皮细胞的丧失。 PAH中的依赖性血管扩张。在特定目标1中，我们将使用内皮特异性TRPV4和 Caveolin-1基因敲除小鼠和人肺定义一种新的Caveolin-1·PKC·TRPV4血管扩张信号 控制内皮细胞调节PAP的复合体。在特定目标2中，我们将检验提升的假设 过氧亚硝酸盐水平破坏PAH中小窝蛋白-1·PKC·TRPV4血管扩张信号复合体。我们还将确定 降低PAH中的过氧亚硝酸盐水平是否以TRPV4依赖的方式降低PAP。这些研究将 确定小动脉内皮细胞TRPV4通道异常参与了PAH，并奠定了 为挽救内皮细胞TRPV4通道功能的新治疗策略奠定基础。

Abstract Pulmonary arterial hypertension (PAH) is a disease of pulmonary vasculature with a high mortality rate of up to 45% three years after diagnosis. PAH is often associated with the loss of endothelium-dependent vasodilation, which has long been thought to be a major contributor to development of PAH. However, the underlying mechanisms for the loss of endothelium-dependent vasodilation in PAH remain unclear, particularly in the native endothelium from small pulmonary arteries (PAs) that control pulmonary arterial pressure. We recently showed that endothelial TRPV4 (transient receptor potential vanilloid 4) channels are key regulators of endothelium- dependent vasodilation in PAs. In this application, we provide novel preliminary data that endothelial TRPV4 channels regulate resting pulmonary arterial pressure (PAP), and are impaired in PAH. Moreover, we show that scaffolding protein caveolin-1 provides a signaling platform for protein kinase C (PKC)-dependent regulation of TRPV4 channels, a mechanism that is defective in PAH. Interestingly, two different peroxynitrite scavengers restored endothelial TRPV4 channel activity in PAH, suggesting that peroxynitrite may be a key contributor to dysfunction of TRPV4 channel function. Additionally, exogenous peroxynitrite also impaired caveolin-1·PKC regulation of endothelial TRPV4 channel function. We, therefore, hypothesize that peroxynitrite-induced impairment in caveolin-1·PKC regulation of TRPV4 channel function contributes to the loss of endothelium- dependent vasodilation in PAH. In Specific Aim 1, we will use PAs from endothelium-specific TRPV4 and caveolin-1 knockout mice and human lungs to define a novel caveolin-1·PKC·TRPV4 vasodilator signaling complex that controls endothelial regulation of PAP. In Specific Aim 2, we will test the hypothesis that elevated peroxynitrite levels disrupt caveolin-1·PKC·TRPV4 vasodilator signaling complex in PAH. We will also determine whether lowering peroxynitrite levels in PAH reduces PAP in a TRPV4-dependent manner. These studies will establish that abnormalities in endothelial TRPV4 channels in small PAs contribute to PAH, and lay the foundation for novel therapeutic strategies to rescue endothelial TRPV4 channel function.