A molecular approach to the pathogenesis of portal hypertension

门脉高压发病机制的分子方法

• 批准号: 9761521
• 负责人: DON C. ROCKEY
• 金额: $ 33.91万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-20 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761521
• 关键词: Abnormal Endothelial Cell; Adaptor Signaling Protein; Affect; Area; Binding; Biochemical; Biology; Blood flow; Cells; Clinical; Complex; Data; Defect; Disease; Endothelial Cells; Endothelium; Etiology; Exhibits; Extrahepatic; Foundations; Future; G protein coupled receptor kinase; GIT1 gene; Goals; Hemorrhage; Hepatic Stellate Cell; Human; Intestines; Investigation; Laboratories; Lead; Liquid substance; Liver; Liver Fibrosis; Liver diseases; Macromolecular Complexes; Mediating; Medical; Molecular; Morbidity - disease rate; NOS3 gene; Nitric Oxide; Nitric Oxide Synthase; Pathogenesis; Pathway interactions; Patients; Phenotype; Phosphorylation; Physiological; Play; Portal Hypertension; Post-Translational Protein Processing; Production; Proteins; Regulation; Resistance; Role; Seminal; Series; Signal Transduction; Signaling Molecule; Structure; Testing; Therapeutic; Translating; Tyrosine Phosphorylation; Vascular Diseases; Vasoconstrictor Agents; Vasodilation; Vasodilator Agents; Work; base; clinically relevant; endothelial dysfunction; experimental study; in vivo; injured; innovation; intrahepatic; liver injury; mortality; new therapeutic target; novel; novel therapeutics; scaffold; spatiotemporal; vascular bed; vasoconstriction

Increased resistance to sinusoidal blood flow is an important component of early as well as advanced portal hypertension. This results from an imbalance in intrahepatic vasoconstrictor and vasodilator molecules, the latter including nitric oxide (NO). Our laboratory has been on the cutting edge of advances in understanding the molecular basis for the imbalance in NO. Seminal among our discoveries is that there is a (dramatic and remarkable) reduction in endothelial NO synthase (eNOS) dependent NO release by sinusoidal endothelial cells (SECs). Our focus has been on understanding the mechanism underlying this defect. Preliminary data presented in the current application has identified highly novel post-translational defects in eNOS in SECs after liver injury, including reduced phosphorylation of eNOS caused by reduced levels of a novel protein known as G-protein coupled receptor (GPCR) kinase interactor-1 (GIT1) that regulates eNOS phosphorylation, activity and NO production. In the basal state, GIT1 is the most potent stimulator of eNOS we have identified to date. Extensive new preliminary data provide a foundation for the hypothesis that GIT1 acts GIT1 acts as a scaffolding partner for a macromolecular complex including eNOS and other proteins that together regulate eNOS function in a spatiotemporal fashion. Importantly, the reduction in GIT1 expression after liver injury, have led us to hypothesize that post-translational defects in eNOS after liver injury are critical in the sinusoidal endothelialopathy that accompanies liver injury, and further, that GIT1 is a central component. The overarching goals of this new project are twofold. First, with a future objective being to translate our work to humans with liver disease, we wish to validate the importance of GIT1 in vivo. Secondly, we wish to uncover fundamental basic mechanisms that regulate eNOS function. Therefore, our specific aims are as follows: We will (1) define the functional importance of GIT1 in vivo in normal and injured liver, (2) characterize the molecular interaction between GIT1 and eNOS, and determine how GIT1 tyrosine phosphorylation affects this interaction and eNOS function, and (3) determine how the GIT1 binding partner, β−PIX (an integral component of a putative multiprotein signaling module) contributes to regulating eNOS function. The proposed experiments will uncover novel mechanistic aspects of eNOS structure and function and as such have fundamental therapeutic implications not only for patients with liver disease and portal hypertension, but also for those with other vascular disorders.

对正弦血流的阻力增加也是早期 晚期门静脉高压症这是由于肝内血管收缩剂的失衡 和血管扩张剂分子，后者包括一氧化氮（NO）。我们的实验室一直在 尖端的进展，了解分子基础的不平衡，在一氧化氮。 在我们的发现中，有一个（戏剧性的和显著的）减少， 内皮型一氧化氮合酶（eNOS）依赖的窦状隙内皮细胞（SEC）释放NO。 我们的重点是了解这种缺陷背后的机制。初步 本申请中提供的数据已经鉴定了高度新颖的翻译后缺陷， 肝损伤后SEC中的eNOS，包括由eNOS磷酸化减少引起的eNOS磷酸化减少， 一种称为G蛋白偶联受体（GPCR）激酶相互作用物-1的新蛋白质水平 （GIT 1），其调节eNOS磷酸化、活性和NO产生。在基础状态下， GIT 1是我们迄今为止发现的最有效的eNOS刺激剂。广泛的新 初步数据为GIT 1作为一种生物学行为的假设提供了基础。 包括eNOS和其他蛋白质的大分子复合物的支架伴侣， 一起以时空方式调节eNOS功能。重要的是，GIT 1的减少 肝损伤后eNOS的表达，使我们假设eNOS的翻译后缺陷， 肝损伤后，在伴随肝损伤的窦状隙内皮病变中至关重要， 此外，GIT 1是一个核心组件。 这个新项目的首要目标是双重的。首先，未来的目标是 为了将我们的工作转化为肝病患者，我们希望验证GIT 1在以下方面的重要性： vivo.其次，我们希望揭示调控eNOS的基本机制， 功能因此，我们的具体目标如下：我们将（1）定义功能 GIT 1在正常和损伤肝脏中的体内重要性，（2）表征分子相互作用 GIT 1和eNOS之间的关系，并确定GIT 1酪氨酸磷酸化如何影响这一点， 相互作用和eNOS功能，以及（3）确定GIT 1结合伴侣β-PIX（一种 推定的多蛋白信号传导模块的组成部分）有助于调节eNOS 功能所提出的实验将揭示eNOS结构的新机制方面 和功能，因此不仅对患有糖尿病的患者具有基本的治疗意义， 肝脏疾病和门静脉高压症，但也适用于那些与其他血管疾病。