A molecular approach to the pathogenesis of portal hypertension

门脉高压发病机制的分子方法

基本信息

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
项目类别：
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

项目摘要

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的重要组成部分晚期门静脉高压是由于肝内血管收缩失衡所致。和血管扩张分子，后者包括一氧化氮（NO）。在理解 NO 不平衡的分子基础方面取得了前沿进展。研讨会上我们的发现是，（显着且显着的）窦内皮细胞 (SEC) 依赖内皮 NO 合酶 (eNOS) 释放 NO。我们的重点是初步了解这一缺陷的机制。当前申请中提供的数据已识别出高度新颖的翻译后缺陷肝损伤后 SEC 中的 eNOS，包括因减少而引起的 eNOS 磷酸化减少一种称为 G 蛋白偶联受体 (GPCR) 激酶相互作用因子 1 的新型蛋白质的水平 (GIT1) 在基础状态下调节 eNOS 磷酸化、活性和 NO 产生。 GIT1 是我们迄今为止发现的最有效的 eNOS 刺激剂。初步数据为 GIT1 充当 GIT1 充当大分子复合物的支架搭档，包括 eNOS 和其他蛋白质共同以时空方式调节 eNOS 功能，重要的是 GIT1 的减少。肝损伤后的表达，使我们发现了 eNOS 的翻译后缺陷肝损伤后对于适应肝损伤的肝窦内皮病至关重要，并且此外，GIT1 是一个核心组件。这个新项目的总体目标有两个：首先，未来的目标是。为了将我们的工作转化为患有肝病的人类，我们希望验证 GIT1 在其次，我们希望揭示调节 eNOS 的基本机制。因此，我们的具体目标如下：我们将（1）定义泛函。 GIT1 在体内正常和受损肝脏中的重要性，(2) 表征分子相互作用 GIT1 和 eNOS 之间的差异，并确定 GIT1 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 GIT1 结合伴侣 β−PIX（一种假定的多蛋白信号传导模块的组成部分）有助于调节 eNOS 所提出的实验将揭示 eNOS 结构的新机制。和功能，因此不仅对患有以下疾病的患者具有根本的治疗意义肝脏疾病和门静脉高压症，也适用于患有其他血管疾病的患者。