Mechanisms Regulating Vascular Homeostasis

调节血管稳态的机制

基本信息

批准号：
10475687
负责人：
Christopher D Kontos
金额：
$ 52.67万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10475687
关键词：
ANGPT1 gene Address Adhesions Angiopoietins Apolipoprotein E Atherosclerosis Binding Binding Sites Biology Blood Vessels CRISPR/Cas technology Calmodulin Cardiovascular Diseases Cell Survival Cell physiology Cessation of life Co-Immunoprecipitations Coronary heart disease Defect Endothelial Cells Endothelium Event Gene Expression Genetic Genetic Transcription Goals Health Homeostasis Hypertension In Vitro Inflammation Lead Ligands Link Liquid substance Malignant Neoplasms Mediating Modeling Molecular Mus Myography NOS3 gene Nitric Oxide Oxygen Pathologic Neovascularization Perfusion Permeability Phenotype Phosphorylation Play Proteins Public Health Receptor Signaling Recombinant Proteins Regulation Regulatory Pathway Retinal Diseases Role Scaffolding Protein Septic Shock Signal Pathway Signal Transduction Testing Transcription Factor AP-1 Vascular Diseases Vascular Permeabilities Vascular remodeling angiogenesis atheroprotective base cardiovascular disorder prevention density endothelial dysfunction hypertensive in vivo induced pluripotent stem cell loss of function monocyte mutant novel pressure prevent receptor response rho shear stress transcription factor vascular inflammation western diet

项目摘要

PROJECT SUMMARY Regulation of normal endothelial cell (EC) function plays a critical role in vascular homeostasis and the prevention of cardiovascular disease (CVD). Endothelial dysfunction in CVD is characterized by loss of endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO). The Tie receptors and their ligands, the angiopoietins (Ang), are important regulators of vascular homeostasis and the transition from EC quiescence to "activation" and vascular remodeling. Whereas Ang-1/Tie2 signaling promotes EC survival and quiescence, in part through activation of Akt and eNOS, the homologous Tie1 receptor has been shown to promote EC activation, inflammation, and atherosclerosis. However, Tie1 is also required for Tie2-mediated angiogenesis, and Tie1's overall functional effects appear to be context-dependent and linked, in part, to the presence of inflammation. Unlike Tie2, Tie1 has no known activating ligands, therefore its signaling pathways and mechanisms of action have been difficult to study and remain poorly understood. We identified a novel and previously uncharacterized molecular scaffolding protein, Caskin2, as a Tie1-interacting protein. Although few studies have specifically addressed Caskin2's function, it has been identified as a strong marker of ECs, and numerous molecular studies have linked Caskin2 to phenotypes associated with defects in vascular homeostasis. Importantly, our studies indicate that Caskin2 is a critical molecular link between Tie receptor signaling, eNOS biology, and vascular homeostasis. Our preliminary studies in this proposal demonstrate that Caskin2 is highly expressed in ECs in vitro and in vivo and that Caskin2 promotes EC quiescence and survival in vitro. Caskin2 binding to Tie1 is disrupted by phosphorylation of T794 on Tie1, an event that is mediated by PAK in a Rac-dependent manner and that is required for angiogenesis. Moreover, Caskin2 is required for Ang- 1/Tie2-mediated signaling through Akt, suggesting that Caskin2 integrates signals from both Tie1 and Tie2 to regulate vascular homeostasis. Furthermore, Caskin2 binds eNOS and its activator calmodulin (CaM) and increases eNOS expression and activity and is upregulated by fluid shear stress and by KLF2. Finally, we show that Caskin2–/– mice have increased vascular permeability, atherosclerosis, pathological angiogenesis, and are hypertensive, all disorders of vascular homeostasis characterized by abnormal eNOS signaling. Based on these findings, we hypothesize that Caskin2 is a critical integrator of Tie receptor signaling that regulates vascular homeostasis in part through eNOS activation. To test this hypothesis, the Specific Aims of this proposal are to: 1) Determine the molecular mechanisms by which Caskin2 regulates Tie receptor-mediated endothelial function and eNOS activity; 2) Determine the mechanisms by which Caskin2 responds to and senses changes in fluid shear stress to regulate EC phenotypes in vitro; and 3) Determine the effects of Caskin2 deficiency on vascular homeostasis in vivo.

项目概要正常内皮细胞 (EC) 功能的调节在血管稳态和预防心血管疾病（CVD）的特点是内皮功能障碍。内皮一氧化氮合酶 (eNOS) 衍生的一氧化氮 (NO)。血管生成素 (Ang) 是血管稳态和 EC 静止状态转变的重要调节剂 Ang-1/Tie2 信号传导促进 EC 存活和静止，同源 Tie1 受体部分通过 Akt 和 eNOS 的激活来促进 EC 然而，Tie1 也是 Tie2 介导的血管生成所必需的。 Tie1 的整体功能效果似乎与环境相关，并且部分与与 Tie2 不同，Tie1 没有已知的激活配体，因此其信号通路和炎症。其作用机制一直难以研究，而且人们对它的了解仍知之甚少。以前未表征的分子支架蛋白 Caskin2 作为 Tie1 相互作用蛋白虽然很少。研究专门探讨了 Caskin2 的功能，它已被确定为 EC 的强有力标志物，并且许多分子研究已将 Caskin2 与血管缺陷相关的表型联系起来。重要的是，我们的研究表明 Caskin2 是 Tie 受体之间的关键分子联系。我们在本提案中的初步研究表明，信号传导、eNOS 生物学和血管稳态。 Caskin2 在体外和体内的 EC 中高表达，Caskin2 促进 EC 静止和存活 Caskin2 与 Tie1 的结合被 Tie1 上 T794 的磷酸化破坏，这是由 Tie1 介导的事件。 PAK 以 Rac 依赖性方式存在，并且是血管生成所必需的。此外，Caskin2 是 Ang- 所必需的。 1/Tie2 通过 Akt 介导的信号传导，表明 Caskin2 整合了来自 Tie1 和 Tie2 的信号此外，Caskin2 还可以结合 eNOS 及其激活剂钙调蛋白 (CaM)，并调节血管稳态。增加 eNOS 表达和活性，并通过流体剪切应力和 KLF2 上调。表明 Caskin2–/– 小鼠血管通透性增加、动脉粥样硬化、病理性血管生成、和高血压，所有以异常 eNOS 信号传导为特征的血管稳态疾病。根据这些发现，我们发现 Caskin2 是 Tie 受体信号传导的关键整合者，部分通过 eNOS 激活调节血管稳态。该提案的目的是： 1) 确定 Caskin2 调节 Tie 的分子机制受体介导的内皮功能和 eNOS 活性；2) 确定 Caskin2 的机制响应并感知流体剪切应力的变化以调节体外 EC 表型；3) 确定 Caskin2 缺陷对体内血管稳态的影响。