Microvascular endothelial Kir channels in flow-induced dilation and hypertension

微血管内皮 Kir 通道在血流引起的扩张和高血压中的作用

• 批准号: 9917815
• 负责人: Irena Levitan
• 金额: $ 62.74万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-19 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9917815
• 关键词: AKT1 gene; Address; Anti-Inflammatory Agents; Arteries; Biology; Blood Pressure; Blood Vessels; Blood flow; Cardiovascular Diseases; Cell membrane; Charge; Complex; Couples; Coupling; Data; Depressed mood; Development; Disease; Elements; Endothelial Cells; Endothelium; Event; Generations; Genetic; Glycocalyx; Goals; Harvest; Heparitin Sulfate; Human; Hypertension; Impairment; In Vitro; Investigation; KDR gene; Knock-out; Link; Mediating; Membrane; Microcirculation; Modeling; Morbidity - disease rate; Mus; NOS3 gene; Nitric Oxide; Nitric Oxide Synthase; PTEN gene; Patients; Phosphatidylinositol 4,5-Diphosphate; Phospholipids; Phosphoric Monoester Hydrolases; Phosphorylation; Play; Potassium Channel; Production; Protein-Serine-Threonine Kinases; Recovery; Recovery of Function; Regulation; Relaxation; Research Design; Resistance; Role; Signal Pathway; Signal Transduction; Testing; Vascular Endothelial Cell; Vasodilation; Vasodilator Agents; base; blood pressure regulation; cohort; functional loss; hemodynamics; insight; inward rectifier potassium channel; mechanotransduction; mortality; mouse model; novel; overexpression; prehypertension; recruit; response; sensor; shear stress; syndecan; vascular endothelial dysfunction; virtual

Abstract: Flow-induced vasodilation (FIV) is a hallmark of the endothelial response to flow and an essential mechanism for the control of blood flow to the microcirculation. It is well established that a key mechanism responsible for FIV is generation of nitric oxide (NO). Our recent study discovered that FIV and flow-induced generation of NO in resistance arteries of mice and humans critically depend on endothelial inwardly-rectifying K+ channels (Kir2.1). We also established that Kir2.1 regulate endothelial NO synthase (eNOS) via a serine/threonine kinase Akt1. This was particularly interesting and important because Kir channels have long been known to be sensitive to shear stress but their role in endothelial responses to flow remained unknown. The goals of this proposal are to determine the mechanisms by which Kir2.1 channels couple hemodynamic shear stress forces to activation of endothelial NO synthase (eNOS) and NO production and to evaluate the role of endothelial Kir channels in vasoreactivity of human vessels in hypertension. Our first aim is to elucidate the mechanism responsible for the sensitivity of Kir2.1 channels to shear stress, which is currently completely unknown. Our preliminary data show that flow-sensitivity of Kir2.1 is abrogated by enzymatic degradation of Heparan Sulphate (HS)-Glycocalyx and reduced in ECs isolated from Sydecan1-/- mice. We propose, therefore, that flow-induced activation of Kir channels is mediated by the endothelial Glycocalyx, specifically Syndecan-1, and possibly other elements of HS-Glycocalyx. We also propose that Kir2.1 interacts directly with Syndecan-1, and elucidate the mechanism of this interaction. Our second aim focuses on the mechanism that couples Kir2.1 to the downstream Akt1 signaling pathway. It is well-known that flow-induced activation of AKT1 requires its translocation and recruitment to the membrane via association with a phospholipid PIP3. We propose that Kir enhances the association of Akt1 with PIP3 and thus facilitates its recruitment to the membrane, resulting in increased Akt1 phosphorylation. We also explore the possibilities that flow-induced activation of Kir2.1 may regulate the upstream events, such as activation PI3K and its recruitment to VEGFR2 mechanosensing complex or inhibit a phosphatase PTEN that converts PIP3 to PIP2. This signaling mechanism is explored in primary endothelial cells and in intact resistance arteries freshly-harvested from mice. A new endothelial-specific inducible mouse model of Kir2.1 deficiency has been generated in our lab to achieve these goals. In aim 3, we propose to test the hypothesis that microvascular endothelial Kir function is depressed during human hypertension. This aim is based on our preliminary data showing decreased contribution of Kir2.1 to FIV in a pilot cohort of hypertensive patients. In this study, we will recruit 3 groups of subjects that include patients with pre-hypertension or stage 1 hypertension and healthy controls. We will also determine whether the loss of Kir2.1 contribution to FIV should be attributed to the loss of the functional expression of Kir2.1 channels or to their impaired coupling to the downstream signaling. Finally, we will also determine whether impaired FIV in hypertensive patients may be rescued by restoring Kir2.1 activity.

抽象的： 流动诱导的血管舒张（FIV）是内皮反应的标志， 控制流向微循环的基本机制。它已经建立了 负责FIV的关键机制是一氧化氮的产生（NO）。我们最近的研究 发现FIV和流动引起的NO在小鼠的抗性动脉中的NO产生 人类严重取决于内皮内皮向内矫正的K+通道（KIR2.1）。我们也是 确定KIR2.1通过丝氨酸/苏氨酸激酶调节内皮NO合酶（ENOS） AKT1。这特别有趣且重要，因为KIR频道长期以来一直是 已知对剪切应力敏感，但它们在内皮反应中的作用仍然存在 未知。该提案的目标是确定KIR2.1渠道的机制 夫妇血流动力学剪切应力激活内皮NO合酶（ENOS）和 没有生产并评估内皮kiR通道在人体血管反应性中的作用 高血压中的血管。我们的第一个目的是阐明负责 Kir2.1通道对剪切应力的敏感性，目前完全未知。我们的 初步数据表明，Kir2.1的流敏性通过酶促降解而被废除 硫酸乙酰肝素（HS） - 糖蛋白细胞酶，并在从Sydecan1 - / - 小鼠中分离出的EC中降低。我们 因此，提出，流动诱导的KIR通道的激活是由内皮介导的 糖蛋白，特别是syndecan-1，以及HS-糖果的其他元素。我们也是 提出Kir2.1与Syndecan-1直接相互作用，并阐明了此机制 相互作用。我们的第二个目标重点是将kir2.1耦合到下游的机制 AKT1信号通路。众所周知，流动诱导的Akt1激活需要其 通过与磷脂PIP3结合的易位和募集到膜。我们 提出KIR可以增强AKT1与PIP3的关联，从而促进其招聘 到膜，导致AKT1磷酸化增加。我们还探索了可能性 流动诱导的Kir2.1激活可能会调节上游事件，例如激活PI3K 并募集到VEGFR2机械传感复合物或抑制磷酸酶PTEN 将PIP3转换为PIP2。在原代内皮细胞和 完整的抗性动脉从小鼠新鲜收获。新的内皮特异性诱导 在我们的实验室中已经产生了Kir2.1缺乏症的鼠标模型以实现这些目标。目标 3，我们建议测试微血管内皮kir功能降低的假设 在人类高血压期间。此目的基于我们的初步数据显示下降 Kir2.1对高血压患者的试点队列中FIV的贡献。在这项研究中，我们将招募 3组受试者，包括赫化学前或1阶段高血压的患者 健康控制。我们还将确定KIR2.1对FIV的贡献是否应该是 归因于KIR2.1通道的功能表达的丧失或耦合受损 到下游信号传导。最后，我们还将确定FIV是否受损 高血压患者可以通过恢复KIR2.1活性来挽救。