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

基本信息

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
项目类别：
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

项目摘要

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：血流诱导血管舒张 (FIV) 是内皮细胞对血流反应的标志，控制微循环血流的重要机制。已经很完善了导致 FIV 的一个关键机制是一氧化氮 (NO) 的产生。我们最近的研究发现 FIV 和血流诱导小鼠阻力动脉中 NO 的产生人类严重依赖内皮内向整流 K+ 通道 (Kir2.1)。我们也确定 Kir2.1 通过丝氨酸/苏氨酸激酶调节内皮 NO 合酶 (eNOS) Akt1。这是特别有趣和重要的，因为 Kir 通道长期以来一直存在已知对剪切应力敏感，但它们在内皮对血流反应中的作用仍然存在未知。该提案的目标是确定 Kir2.1 通道的机制将血流动力学剪切应力与内皮一氧化氮合酶 (eNOS) 的激活相耦合 NO 产生并评估内皮 Kir 通道在人类血管反应性中的作用高血压中的血管。我们的首要目标是阐明造成这一现象的机制 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 的流量敏感性被酶降解所消除。硫酸乙酰肝素 (HS)-糖萼并在从 Sydecan1-/- 小鼠中分离的 EC 中减少。我们因此，提出流动诱导的 Kir 通道激活是由内皮细胞介导的 Glycocalyx，特别是 Syndecan-1，可能还有 HS-Glycocalyx 的其他元素。我们也提出Kir2.1直接与Syndecan-1相互作用，并阐明其机制相互作用。我们的第二个目标集中于Kir2.1与下游的耦合机制 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 结合易位并募集到膜上。我们提出 Kir 增强 Akt1 与 PIP3 的关联，从而促进其招募到膜上，导致 Akt1 磷酸化增加。我们也探索各种可能性流动诱导的 Kir2.1 激活可能调节上游事件，例如激活 PI3K 及其招募到 VEGFR2 机械传感复合物或抑制磷酸酶 PTEN 将 PIP3 转换为 PIP2。在原代内皮细胞和从小鼠身上新鲜采集的完整抵抗动脉。一种新的内皮特异性诱导物我们的实验室已经建立了 Kir2.1 缺陷小鼠模型来实现这些目标。瞄准目标 3、我们提出检验微血管内皮Kir功能被抑制的假设在人类高血压期间。这一目标是基于我们的初步数据显示减少 Kir2.1 在高血压患者试点队列中对 FIV 的贡献。在本研究中，我们将招募 3 组受试者，包括高血压前期或 1 期高血压患者健康的控制。我们还将确定 Kir2.1 对 FIV 贡献的损失是否应该归因于 Kir2.1 通道功能表达的丧失或其耦合受损到下游信令。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。