Endothelial Myocyte Matrix in Cardiac Remodeling

项目主任/首席调查员(最后、第一、中间)：Tyagi，Suresh C.， 本项目的总体目标是了解心内膜内皮细胞-心肌细胞(E-M)的机制。 慢性心力衰竭的功能障碍。前一资助时期的研究表明，心内膜 内皮功能障碍与氧化基质堆积(纤维化)增加、潜伏期激活有关 心肌基质金属蛋白酶与心肌组织抑制物失活 金属蛋白酶(TIMP-4)继发于氧化和蛋白水解性应激。TIMP-4的给药研究 改善活性氧(ROS，氧化应激)的形成和基质金属蛋白酶的激活 (蛋白分解应激)。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解偶联中的作用仍不清楚。硫化氢气体的威力最大 抗氧化剂在减轻氧化应激中的作用和最近的研究表明，硫化氢具有心脏保护作用。这个 这一竞争性更新方案的中心假设是，在慢性心力衰竭期间，氧化和 蛋白水解性应激诱导PAR-1，导致产生线粒体ROS和活性氮物种 (Rns)和线粒体一氧化氮合酶(MtNOS)，从而激活潜伏期驻留心脏 MMPs。这些事件破坏了基质金属蛋白酶/TIMP轴，导致内皮和心肌细胞之间的纤维化。 硫化氢治疗减轻纤维化，减轻E-M解偶联。因此，这一行动的具体目的是 建议是：#1：确定慢性左心室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H_2S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、基质金属蛋白酶-2、-9、-13、组织基质金属蛋白酶-1、-3、降低基质金属蛋白酶-4和 诱导PAR-1和硫化氢可减轻心肌纤维化。#3：确定慢性LV容量超负荷 通过诱导PAR-1和H_2S减少E-M解偶联，导致E-M功能障碍和左心室肥厚。慢性心力衰竭 将由野生型(WT)动静脉瘘(AVF)、PAR-1-/+、iNOS-/-、 MMP9-/-、TIMP-3-/-和TIMP-4++/++小鼠，用或不用硫化氢供体NaHS治疗。 PHS 398/2590(11/07版)页面续格式页面

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