Endothelial Piezo1 channel and cerebral blood flow control

项目概要/摘要： 脑血流量（CBF）是精确控制，以满足神经元的代谢需求。活动神经元信号 通过多个神经血管耦合机制连接到脉管系统，以增加 这种现象称为功能性充血（FH）。充血反应增加了摩擦力 由血流施加到小动脉和毛细血管的内皮细胞（EC）上。我们最近展示了 Piezo 1通道是脑毛细血管内皮细胞中一个重要的机械传感器，它介导Ca 2+信号， 对机械刺激的反应。然而，Piezo 1信号传导对CBF控制的影响仍然未知。在 对NIH特别关注通知（NOT-AT-21-002）“促进内感受及其 对健康和疾病的影响，”我们提供了令人信服的初步证据，表明压电1介导的内感受 在CBF调节中至关重要，并且这种机制在高血压期间受到损害。充分发挥两国 初步数据，我们的目的是测试总体假设，脑血管Piezo 1调节CBF在 局部毛细血管水平和扩展脑区域中的大尺度水平。目标1将采用EC专用 遗传编码的Ca 2+指示小鼠，宽视野和双光子荧光成像，以确定空间， 脑毛细血管中Piezo 1介导的Ca 2+瞬变的时间和传播特征。而且还要 使用遗传和药理学方法来确定Piezo 1介导的Ca 2+信号传导是否与 产生有效的血管扩张剂一氧化氮以增加局部毛细血管血流量。在目标2中，我们 确定FH期间大规模Piezo 1激活如何触发阳离子电导， 超极化介导的FH，很像内置的制动系统。为了实现这一目标，我们将利用基因 在所有EC或脑EC中Piezo 1活性降低的工程小鼠，沿着近红外激光成像， 和激光多普勒血流仪。在目标3中，我们将确定脑血管Piezo 1信号传导是否受到损害， 高血压和Piezo 1通道病变样效应是否最终导致CBF缺陷。我们会直接 在两种高血压小鼠模型和基因工程小鼠模型中测量Piezo 1通道活性和CBF。 携带人类Piezo 1突变的转基因小鼠。该突变的使用具有临床相关性，因为PIEZO 1 突变在非洲裔美国人中普遍存在，非洲裔美国人是高血压患病率最高的人群 国际吧该项目的完成将支持Piezo 1在CBF调节中至关重要的概念， 其活性的改变是CBF下降的一个新的危险因素。这项工作将进一步提供新的治疗靶点 用于改善心血管疾病的CBF。

Project Summary/Abstract: Cerebral blood flow (CBF) is precisely controlled to satisfy neuronal metabolic demands. Active neurons signal to the vasculature via multiple neurovascular coupling mechanisms to increase regional blood flow in a phenomenon known as functional hyperemia (FH). The hyperemic response increases the frictional forces imposed by blood flow onto endothelial cells (ECs) of arterioles and capillaries. We have recently demonstrated that the Piezo1 channel is a crucial mechanosensor in brain capillary ECs, and that it mediates Ca2+ signals in response to mechanical stimuli. However, the impact of Piezo1 signaling on CBF control remains unknown. In response to the NIH Notice of Special Interest (NOT-AT-21-002) “Promoting Research on Interoception and Its Impact on Health and Disease,” we provide compelling preliminary evidence that Piezo1-mediated interoception is crucial in CBF regulation, and that this mechanism is compromised during hypertension. Building on our preliminary data, we aim to test the overarching hypothesis that cerebrovascular Piezo1 regulates CBF at the local capillary level and at the large-scale level in extended brain regions. Aim 1 will employ EC-specific genetically encoded Ca2+ indicator mice, widefield and two-photon fluorescence imaging to determine the spatial, temporal, and spread characteristics of Piezo1-mediated Ca2+ transients in brain capillaries. Moreover, we will use genetic and pharmacological approaches to determine if Ca2+ signaling mediated by Piezo1 is coupled to the production of the potent vasodilator nitric oxide to increase local capillary blood flow. In Aim 2, we will determine how large-scale Piezo1 activation during FH triggers a cationic conductance, which dampens hyperpolarization-mediated FH, much like a built-in brake system. To achieve this goal, we will use genetically engineered mice with reduced Piezo1 activity in all ECs or brain ECs, along with near infrared laser imaging, and laser doppler flowmetry. In Aim 3, we will determine if cerebrovascular Piezo1 signaling is compromised in hypertension and whether a Piezo1 channelopathy-like effect leads ultimately to CBF deficits. We will directly measure Piezo1 channel activity and CBF in two mouse models of hypertension and in genetically engineered transgenic mice that harbor a human Piezo1 mutation. Use of this mutation is clinically relevant, in that PIEZO1 mutations are prevalent in African Americans, a population with the highest prevalence of hypertension worldwide. Completion of this project will support the concept that Piezo1 is crucial in CBF regulation, and that alteration of its activity is a novel risk factor for CBF decline. This work will further provide new therapeutic targets for improving CBF in cardiovascular disease.