Pathogenesis and Treatment of Experimental Peritonitis

描述（由申请人提供）： 肠粘膜屏障功能紊乱可能在肠梗阻的发病机制中起重要作用 全身性感染危重患者。宿主防御机制的扰动导致肠道中诱导型一氧化氮合酶（iNOS）的持续上调，可能导致肠粘膜屏障功能的深刻改变。有证据表明，过氧亚硝酸盐（ONOO-），一个强大的氧化剂形成的NO与mperoxide的反应，可能是一个关键的反应性氮中间体负责细胞病变的影响NO在炎症条件下，如内毒素血症，炎症性肠病（IBD），或坏死性小肠结肠炎。我们的目标是确定NO或ONOO-的过度产生可能促进组织损伤（肠上皮细胞凋亡或坏死）和抑制组织修复机制（通过肠上皮细胞迁移和增殖的上皮恢复）的机制，从而导致肠屏障衰竭。我们提出两个具体目标。目的一：探讨ONOO诱导肠上皮细胞凋亡的可能机制。我们将研究ONOO-在各种肠细胞系中的致细胞病变效应以及可能涉及的生化途径（线粒体失调、半胱天冬酶和PARS激活）。目的二：探讨NO或ONOO-抑制组织修复机制、上皮修复和增殖的机制。我们将研究ONOO-如何通过肠上皮细胞迁移影响上皮细胞的恢复，这是修复粘膜损伤的增殖反应之前的关键阶段。迁移可能部分由Rho-GTP酶调节，其修饰肌动蛋白细胞骨架。我们将确定Rho是否需要肠上皮细胞迁移和应力纤维形成在体外。我们将测试ONOO可以通过硝化酪氨酸激酶Src家族的关键成员的关键酪氨酸残基来抑制迁移和增殖的假设：Src;粘着斑激酶（FAK）;和 P13K我们将尝试用各种细胞保护剂调节Rho、Src激酶或线粒体信号通路，以增强体内NO/ONOO-产生过多（内毒素血症IBD）相关条件下的肠屏障功能。

DESCRIPTION (provided by applicant): Derangement in the intestinal mucosal barrier may play an important role m the pathogenesis of systemic infection critically ill patients. Perturbations in the host defense mechanisms that result in sustained upregulation of inducible nitric oxide synthase (iNOS) in the gut may lead to profound alterations in intestinal mucosal barrier function. Evidence suggests that peroxynitrite (ONOO-), a potent oxidant formed by the reaction of NO with mperoxide, may be a key reactive nitrogen intermediate responsible for the eytopathic effects of NO in inflammatory conditions such as endotoxemia, inflammatory bowel disease (IBD), or necrotizing enterocolitis. Our objective is to determine the mechanisms by which overproduction of NO or ONOO- may promote tissue injury enterocyte apoptosis or necrosis) and inhibit tissue repair mechanisms (epithelial restitution via enterocyte migration and proliferation), thereby leading to gut barrier failure. We propose two specific aims. Aim I: To elucidate the potential mechanisms by which ONOO induces enterocyte apoptosis. We will examine the cytopathic effect of ONOO- in various enterocytic cell lines and the biochemical pathways that may be involved (mitochondrial dysregulation, caspases, and PARS activation). Aim II: To investigate the mechanisms by which NO or ONOO- inhibits tissue repair mechanisms, epithelial restitution and proliferation. We will examine how ONOO- affects epithelial restitution by enterocyte migration, the critical phase that precedes the proliferative response to repair the mucosal injury. Migration may be regulated in part by Rho-GTPases, which modify the actin cytoskeleton. We will determine whether Rho is required for enterocyte migration and stress fiber formation in vitro. We will test the hypothesis that ONOO can inhibit migration and proliferation by nitrating critical tyrosine residues of key members of the Src family of tyrosine kinases: Src; focal adhesion kinase (FAK); and P13K. We will attempt to modulate Rho, Src kinase, or mitochondrial signaling pathways with various cytoprotective agents to enhance intestinal barrier function in conditions associated with excessive NO/ONOO- production (endotoxemia IBD) in vivo.