Endothelial Myocyte Matrix in Cardiac Remodeling

项目主任/主要研究者（最后，第一，中间）：Tyagi，Suresh C.， 本课题的总体目标是了解内皮细胞（endothelial-myocyte，E-M）的内皮化机制 慢性心力衰竭中的功能障碍。上一个供资期的研究表明， 内皮功能障碍与增加的氧化基质积累（纤维化），潜在的 常驻心肌基质金属蛋白酶（MMPs）和心肌组织抑制剂失活 金属蛋白酶（TIMP-4）继发于氧化和蛋白水解应激。TIMP-4的施用 改善活性氧（ROS，氧化应激）的形成和MMP活化 （蛋白水解应激）。此外，我们还发现了蛋白酶激活受体-1（PAR-1）的诱导作用。 然而，PAR-1在纤维化和E-M解偶联中的作用仍然不清楚。H2S气体是最有效的 抗氧化剂在减轻氧化应激中的作用，最近的研究表明H2S具有心脏保护作用。的 这种竞争性更新建议的中心假设是，在慢性心力衰竭期间， 蛋白水解应激诱导PAR-1，导致产生线粒体（mt）ROS和活性氮物质 (RNS)和线粒体一氧化氮合酶（mtNOS），从而激活潜在的常驻心脏 MMPs这些事件破坏MMP/TIMP轴，引起内皮细胞和肌细胞之间的纤维化。 用H2S处理可减轻纤维化并减轻E-M解偶联。因此，这一具体目标 建议是：#1：确定慢性左心室（LV）容量超负荷是否会导致线粒体 通过诱导NADPH氧化酶（p47亚基）、mtNOS和PAR-1以及H2S来诱导氧化应激（ROS和RNS 减轻线粒体氧化应激。#2：确定慢性LV容量超负荷是否导致 通过增加胶原/弹性蛋白比率、MMP-2、MMP-9、MMP-13、TIMP-1、TIMP-3，降低TIMP-4，以及 诱导PAR-1和H2S减轻心脏纤维化。#3：确定慢性LV容量超负荷 H2S通过诱导PAR-1和H2S降低E-M解偶联而导致E-M功能障碍和LVH。慢性心力衰竭 将由野生型（WT）、PAR-1-/+、iNOS-/-、主动脉-静脉腔静脉瘘（AVF）造成的LV容量超负荷造成 MMP-9-/-、TIMP-3-/-和TIMP-4++/++小鼠，用或不用NaHS（H2S供体）处理。 PHS 398/2590（Rev. 11/07）

Program Director/Principal Investigator (Last, First, Middle): Tyagi, Suresh C., The overall goal of this project is to understand the mechanism of endocardial endothelial-myocyte (E-M) dysfunction in chronic heart failure. Studies from the previous funding period suggested that endocardial endothelial dysfunction is associated with increased oxidized-matrix accumulation (fibrosis), activation of latent resident myocardial matrix metalloproteinases (MMPs) and inactivation of cardiac tissue inhibitor of metalloproteinase (TIMP-4) secondary to oxidative and proteolytic stresses. Administration of TIMP-4 ameliorated both the formation of reactive oxygen species (ROS, oxidative stress) and MMP activation (proteolytic stress). In addition, we discovered the induction of proteinase activated receptor-1 (PAR-1). However, the role of PAR-1 in fibrosis and E-M uncoupling remains poorly defined. H2S gas is the most potent antioxidant in mitigating oxidative stress and recent studies have implicated a cardioprotective role of H2S. The central hypothesis of this competitive renewal proposal is that during chronic heart failure the oxidative and proteolytic stresses induce PAR-1, leading to generate mitochondrial (mt) ROS and reactive nitrogen species (RNS) and mitochondrial nitric oxide synthase (mtNOS), respectively, thus activating the latent resident cardiac MMPs. These events disrupt the MMP/TIMP axis, causing fibrosis between endothelium and myocyte. Treatment with H2S alleviates fibrosis and mitigates E-M uncoupling. Therefore, the specific aims of this proposal are: #1: To determine whether chronic left ventricle (LV) volume overload causes mitochondrial oxidative stress (ROS and RNS) by inducing NADPH oxidase (p47 subunit), mtNOS and PAR-1, and H2S alleviates mitochondrial oxidative stress. #2: To determine whether chronic LV volume overload causes cardiac fibrosis by increasing collagen/elastin ratio, MMP-2, -9, -13, TIMP-1, -3, decreasing TIMP-4, and inducing PAR-1, and H2S mitigates cardiac fibrosis. #3: To determine whether chronic LV volume overload causes E-M dysfunction and LVH by inducing PAR-1 and H2S decreases E-M uncoupling. Chronic heart failure will be created by LV volume overload by aorta-venacava fistula (AVF) in wild type (WT), PAR-1-/+, iNOS-/-, MMP-9-/-, TIMP-3-/-, and TIMP-4++/++ mice, treated with or without NaHS, a H2S donor. PHS 398/2590 (Rev. 11/07) Page Continuation Format Page