STRESS SIGNALING PATHWAYS LINKING ENDOTHELIAL INJURY TO GRAFT ARTERIOSCLEROSIS

描述（由申请人提供）：该申请的总体假设是移植物动脉硬化（GA）是晚期心脏移植失败的主要原因，是由慢性热T细胞对异体移植内皮细胞（ECs）的反应引起的，这种反应以血管壁内延迟型超敏DTH的形式出现，局部产生IFN-g， IFN-g负责驱动血管平滑肌细胞（VSMC）增殖和内膜增生。临床相关性和其他实验系统的证据表明，非免疫因素，特别是围手术期移植物应力诱导的改变，是GA发病的重要因素。实验表明，由于围手术期应激而产生的移植物信号（主要来自内皮细胞）可以产生影响T细胞活化和分化的介质。然而，围手术期应激如缺氧如何耦合细胞内信号通路改变内皮细胞同种免疫和GA尚不清楚，这是本项目的主题。我们在内皮细胞中发现了两种主要的细胞内信号蛋白——胞质ask1相互作用蛋白-1 （AIP1）和线粒体硫氧还蛋白-2 (Trx2)，它们可以保护内皮细胞免受氧化应激诱导的损伤。具体来说，细胞质中的AIP1通过其对NADPH氧化酶（Nox）的抑制作用，而线粒体中的Trx2通过其抗氧化活性，阻止缺血再灌注引起的ROS和氧化应激诱导的炎症反应。在本研究中，我们假设移植物内皮细胞（EC）对非免疫性围手术期损伤的反应是由线粒体中的Trx2和细胞质中的AIP1调节的，从而改变EC，从而影响T细胞介导的同种异体免疫和GA。我们提出在以下具体目标中探索这一假设：1)表征aip1调节的胞质信号通路，该信号通路介导围手术期应激诱导反应，改变EC免疫原性和GA进展。2)表征trx2调节的线粒体信号通路，该通路介导围手术期应激诱导反应，改变EC免疫原性和GA进展。如果成功，该研究将提供通过调节ECs中的这两种分子来减少GA发病率或延缓GA进展的治疗策略。

DESCRIPTION (provided by applicant): The overall hypothesis of this application is that graft arteriosclerosis (GA), the major cause of late cardiac allograft failure, results from a chronic hot T cell response to allogeneic graft endothelial cells (ECs) that takes the form of delayed-type hypersensitivity DTH within the vessel wall, locally generating IFN-g which is responsible for driving vascular smooth muscle cell (VSMC) proliferation and intimal hyperplasia. The clinical correlations and evidence from other experimental systems have suggested that non-immune factors, especially peri-operative stress-induced alterations in the graft, are important contributors to GA pathogenesis. It is proposed and demonstrated experimentally that signals in the graft, primarily from ECs, generated as a result of peri-operative stress can produce mediators that influence T cell activation and differentiation. However, how the peri-operative stresses such as hypoxia couple intracellular signaling pathway to alter ECs alloimmunity and GA is not understood, and is the subject of this project. We have identified two major intracellular signaling proteins- cytosolic ASK1-interacting protein-1 (AIP1) and mitochondrial thioredoxin-2 (Trx2) in ECs that protect ECs from oxidative stress-induced injuries. Specifically, AIP1 in the cytoplasm via its inhibitory effect on the NADPH oxidase (Nox) while Trx2 in mitochondria via its anti-oxidant activity, prevent ischemia-reperfusion-elicited ROS and oxidative stress-induced inflammatory responses. In this proposal, we hypothesize that the responses to non-immune peri-operative injuries of graft endothelial cells (EC) are modulated by Trx2 in the mitochondria and AIP1 in the cytosol, altering the EC in a manner that affects T cell- mediated alloimmunity and GA. We propose to explore this hypothesis in the following specific aims: 1) Characterize AIP1-regulated cytosolic signaling pathways that mediate peri-operative stress-induced responses that alter EC immunogenicity and GA progression. 2) Characterize Trx2-regulated mitochondrial signaling pathways that mediate peri-operative stress-induced responses that alter EC immunogenicity and GA progression. If successful, this study will provide therapeutic strategies by modulating these two molecules in ECs to reduce GA incidence or delay GA progression. PUBLIC HEALTH RELEVANCE: Heart transplantation can saves lives of patients with severe heart failure but its success is limited by a form of late rejection, called graft arteriosclerosis (GA), that involves progressive narrowing of the blood vessels supplying the graft and is worthend by peroperative stresses. This application focuses on two critical molecules AIP1 and Trx2 that suppresses the peroperative stresses. If successful, this study will provide therapeutic strategies by modulating these two molecules in grafts to reduce GA incidence or delay GA progression.