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。膜电位是动脉肌细胞收缩能力的关键调节因素，它由血浆控制。 膜离子通道。高血压患者的动脉去极化，导致血管收缩，但 参与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 这些蛋白在高血压过程中的作用尚不清楚。这种知识的缺乏很大程度上是因为 TRP亚家族在控制血压的动脉肌细胞中的表达、调节和功能 尚不清楚，没有产生特定的Trp通道调节剂和全局Trp通道基因敲除小鼠 对血压有令人困惑的影响。动脉肌细胞表达Trp多囊蛋白1(TRPP1)通道，但血液 这些蛋白质的压力调节，所涉及的信号机制，以及这些蛋白的靶向 蛋白质可以缓解高血压还没有被研究过。对于这个提案，我们创建了第一个条件， 肌细胞特异性TRPP1基因敲除(TRPP1sm-/-)小鼠来验证这些假说。蜂窝电流(I)产生 膜离子通道数由数(N)、开放概率(Po)和单通道数决定 电流(I)，使得i=N.Po.i。以前的研究主要检查了Trp产生的细胞电流(I 心肌细胞中的通道。相比之下，N和Po对海流的贡献却知之甚少。这 应用源于新的初步数据表明，心肌细胞TRPP1通道表面N的调节 Po控制动脉收缩和血压，高血压时TRPP1通道上调， 而心肌细胞特异性的TRPP1基因敲除可以缓解高血压。将调查三个具体目标。目标1 我将检验这样的假设，即心肌细胞TRPP1通道控制动脉收缩能力和全身血液 使用新的、可诱导的、心肌细胞特异性的TRPP1基因敲除小鼠进行压力。目标2将调查这一假说 生理刺激调节心肌细胞TRPP1通道表面丰度和开放概率 控制动脉的收缩能力。目标3将探索以下假设：全身性高血压与 动脉肌细胞TRPP1通道表面表达增加有助于血管收缩 心肌细胞特异性TRPP1消融可降低高血压。用于检验这些假设的方法包括 动脉生物素化，FRET，共IP，免疫荧光，膜片钳电生理，膜电位 记录、细胞内钙成像、动脉肌图和血压遥测。这项提议将 为动脉肌细胞TRPP1调节血压提供有意义的新信息 频道。

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.