Blood pressure regulation by smooth muscle cell ion channels

全身血压由小（阻力大小）动脉的平滑肌细胞（肌细胞）调节， 小动脉动脉肌细胞收缩力的一个关键调节因子是膜电位，它受血浆 膜离子通道高血压患者的动脉去极化，导致血管收缩，但 这种病理改变的机制尚不清楚。动脉肌细胞表达几种不同的 瞬时受体电位（TRP）通道，但生理性全身血压调节和 这些蛋白质在高血压中的参与尚不清楚。这种知识的缺乏主要是因为 TRP亚家族在控制血压的动脉肌细胞中的表达、调节和功能 目前尚不清楚，没有特异性TRP通道调节剂和TRP通道整体敲除小鼠产生 对血压的混乱影响。动脉肌细胞表达TRP多囊蛋白1（TRPP 1）通道，但血液 这些蛋白质的压力调节，涉及的信号传导机制以及靶向这些蛋白质的概念， 还没有研究过引起高血压的蛋白质。对于这个提议，我们创建了第一个条件， 肌细胞特异性TRPP 1敲除（TRPP 1 sm-/-）小鼠来测试这些假设。产生的细胞电流（I） 由膜离子通道群体由数量（N）、开放概率（Po）和单通道确定 电流（i），使得I= N. Po. i。以前的研究主要研究TRP产生的细胞电流（I） 肌细胞中的通道。相比之下，对N和Po对电流的贡献知之甚少。这 应用源于新的初步数据表明，调节肌细胞TRPP 1通道表面N Po控制动脉收缩性和血压，TRPP 1通道在高血压期间上调， 肌细胞特异性TRPP 1基因敲除可导致高血压。将研究三个具体目标。要求1 将检验肌细胞TRPP 1通道控制动脉收缩性和全身血液的假设 压力使用新的，可诱导的，肌细胞特异性TRPP 1敲除小鼠。目标2将研究假设 生理刺激调节肌细胞中TRPP 1通道表面丰度和开放概率， 控制动脉收缩力。目的3将探讨系统性高血压与高血压相关的假设。 动脉肌细胞TRPP 1通道表面表达增加，其有助于血管收缩， 肌细胞特异性TRPP 1消融减轻高血压。用于检验这些假设的方法包括 动脉生物素化，FRET，co-IP，免疫荧光，膜片钳电生理，膜电位 记录、细胞内Ca 2+成像、动脉肌电图和血压遥测。这项建议会 提供了关于动脉肌细胞TRPP 1调节血压的重要新信息 渠道

Systemic blood pressure is regulated by smooth muscle cells (myocytes) of small (resistance-size) arteries and arterioles. A key regulator of arterial myocyte contractility is membrane potential, which is controlled by plasma membrane ion channels. Arteries from hypertensive subjects are depolarized, leading to vasoconstriction, but mechanisms involved in this pathological alteration are unclear. Arterial myocytes express several different transient receptor potential (TRP) channels, but physiological systemic blood pressure regulation and involvement of these proteins during hypertension is unclear. This lack of knowledge exists largely because TRP subfamily expression, regulation and function in myocytes of arteries that control blood pressure is unclear, there are no specific TRP channel modulators and global TRP channel knockout mice produced confusing effects on blood pressure. Arterial myocytes express TRP polycystin 1 (TRPP1) channels, but blood pressure regulation by these proteins, signaling mechanisms involved and the concept that targeting of these proteins alleviates hypertension have not been studied. For this proposal, we created the first conditional, myocyte-specific TRPP1 knockout (TRPP1sm-/-) mice to test these hypotheses. Cellular current (I) generated by a membrane ion channel population is determined by number (N), open probability (Po) and single channel current (i), such that I=N.Po.i. Previous studies have primarily examined cell currents (I) generated by TRP channels in myocytes. In contrast, contributions of N and Po to currents are poorly understood. This application stems from novel preliminary data suggesting that regulation of myocyte TRPP1 channel surface N and Po controls arterial contractility and blood pressure, TRPP1 channels are upregulated during hypertension, and myocyte-specific TRPP1 knockout alleviates hypertension. Three specific aims will be investigated. Aim 1 will examine the hypothesis that myocyte TRPP1 channels control arterial contractility and systemic blood pressure using novel, inducible, myocyte-specific TRPP1 knockout mice. Aim 2 will investigate the hypothesis that physiological stimuli regulate both TRPP1 channel surface abundance and open probability in myocytes to control arterial contractility. Aim 3 will explore the hypothesis that systemic hypertension is associated with an increase in arterial myocyte TRPP1 channel surface expression that contributes to vasoconstriction and that myocyte-specific TRPP1 ablation attenuates hypertension. Methods used to test these hypotheses will include arterial biotinylation, FRET, co-IP, immunofluorescence, patch-clamp electrophysiology, membrane potential recording, intracellular Ca2+ imaging, arterial myography and blood pressure telemetry. This proposal will provide significant novel information concerning blood pressure regulation by arterial myocyte TRPP1 channels.