Novel Calcium Signaling Nanodomains in Vascular Smooth Muscle Cells

平滑肌钙信号机制是动脉收缩和血液的重要调节因素 压力。动脉平滑肌细胞(SMC)钙信号转导机制异常 与血管收缩、血管重塑和血压升高有关 高血压。因此，确定一种新的钙信号转导机制可以提供新的动力。 设计新的治疗靶点以降低高血压患者的血压。在这方面， TRPV4(瞬时受体电位香草素4)离子通道是一种众所周知的钙内流途径 在SMCS中。使用平滑肌特异的TRPV4基因敲除小鼠，我们提供了第一个证据 SMC TRPV4通道可增加静息血压并有助于血压升高 在高血压方面。此外，我们的初步数据显示，两个TRPV4通道包含 SMC中具有相反功能的信号纳米结构域：(1)收缩纳米结构域 涉及神经刺激诱导的α1肾上腺素能受体(α1ARs)-蛋白激酶的激活 C(PKC)-锚定蛋白AKAP150-TRPV4通道信号转导；和(2)扩张器纳米结构域 腔内压力激活，含有小窝蛋白-1支架Piezo1-TRPV4-Ca2+- 激活K+(BK)通道信号。此外，我们还证明了缩窄α1AR-TRPV4通道 高血压和高血压小鼠模型动脉中信号的增强 而扩张器TRPV4-BK通道信号转导减少。我们假设 信号元件之间的错误通信扰乱了收缩和 扩张器信号转导纳米结构域并导致高血压患者血压升高。在目标1中， 我们将使用平滑肌特异的基因敲除小鼠，蛋白质共定位，膜片钳 电生理学和血压无线电遥测来确定分子机制 收缩蛋白α1AR：AKAP150：PKC：TRPV4纳米结构域过度激活的原因 高血压。在目标2中，我们将确定导致减少的分子机制 小窝蛋白-1支架的Piezo1：TRPV4：BK通道纳米结构域的活性 高血压。每个目标的研究的临床相关性将通过以下实验确定 来自非高血压患者和高血压患者的动脉。总的来说，拟议的研究 将建立新的SMC钙信号纳米结构域来控制血压并识别 高血压中这些纳米结构域的特定损伤。

Smooth muscle Ca2+ signaling mechanisms are crucial regulators of arterial contraction and blood pressure. Abnormalities in arterial smooth muscle cell (SMC) Ca2+ signaling mechanisms have been linked to vasoconstriction, vascular remodeling, and blood pressure elevation in hypertension. Therefore, identifying a new Ca2+ signaling mechanism could provide fresh impetus for designing novel therapeutic targets that lower blood pressure in hypertension. In this regard, TRPV4 (transient receptor potential vanilloid 4) ion channels are a well-known Ca2+-influx pathway in SMCs. Using smooth muscle-specific TRPV4-knockout mice, we provided first evidence that SMC TRPV4 channels increase resting blood pressure and contribute to blood pressure elevation in hypertension. Moreover, our preliminary data demonstrate two TRPV4 channel-containing signaling nanodomains in SMCs with opposite functional effects: (1) constrictor nanodomains involving nerve stimulation-induced activation of α1 adrenergic receptors (α1ARs)–protein kinase C (PKC)-anchoring protein AKAP150–TRPV4 channel signaling; and (2) dilator nanodomains activated by intraluminal pressure and comprising caveolin-1 scaffolded Piezo1–TRPV4–Ca2+- activated K+ (BK) channel signaling. Further, we show that constrictor α1AR–TRPV4 channel signaling is accentuated in arteries from a mouse model of hypertension and hypertensive patients, whereas dilator TRPV4–BK channel signaling is reduced. We hypothesize that miscommunication between the signaling elements disrupts the balance between constrictor and dilator signaling nanodomains and leads to blood pressure elevation in hypertension. In Aim 1, we will use smooth muscle-specific knockout mice, protein co-localization, patch-clamp electrophysiology, and blood pressure radiotelemetry to determine the molecular mechanisms underlying the excessive activation of constrictor α1AR:AKAP150:PKC:TRPV4 nanodomains in hypertension. In Aim 2, we will determine the molecular mechanisms responsible for the reduced activity of dilator Piezo1:TRPV4:BK channel nanodomains scaffolded by caveolin-1 in hypertension. The clinical relevance of studies in each Aim will be established by experiments in arteries from non-hypertensive and hypertensive individuals. Collectively, the proposed studies will establish novel SMC Ca2+-signaling nanodomains that control blood pressure and identify specific impairments at these nanodomains in hypertension.