Matrilysin regulation in colonic epithelial cells and role in barrier function

描述(由申请人提供)： 肠道的上皮层形成了一道保护性屏障，将肠腔内容物与肠道的其余部分隔开。肠屏障的完整性依赖于维持上皮细胞与顶端连接复合体和底层基底膜的相互作用。这些相互作用已被证明在肠道感染以及慢性炎症状态下受到损害，例如炎症性肠病。其他实验室以前的工作表明，炎性细胞因子可以改变肠道屏障功能，表现为跨上皮阻力的降低。这些炎性细胞因子影响肠道屏障的确切机制尚不清楚。我们的初步数据表明，基质金属蛋白酶-7(Matrilysin)参与了炎性细胞因子诱导的屏障抵抗改变的发病机制。炎性细胞因子增加了Matrilysin基因的转录以及蛋白质的产生、分泌和激活。激活的基质溶血素可导致培养的结肠上皮细胞系屏障通透性增加。我们的假设是，基质溶素通过裂解位于基底部的顶端连接复合体蛋白和破坏基底膜的黏附来影响结肠上皮屏障[SIC]功能，炎性细胞因子对其的调节在急慢性结肠炎的发生中起作用。三个具体目标将解决上述假设。首先，我们将阐明Matrilysin调节顶端连接复合体蛋白和基底膜黏附蛋白胞外成分脱落的机制。其次，我们将研究炎性细胞因子对基质溶素转录的调节。第三，我们将确定母溶素是否在炎症性肠病和感染性结肠炎小鼠模型的发病中发挥关键作用。这些研究将增加我们对创伤愈合、感染性结肠炎和炎症性肠病的组织培养模型和动物模型中肠上皮细胞维持屏障保护肠道不受管腔内容物影响的机制的理解。这些研究还将确定炎性细胞因子调节基质溶素基因表达的机制。

DESCRIPTION (provided by applicant): The epithelial lining of the intestine forms a protective barrier which separates the luminal contents from the rest of the intestine. The integrity of the intestinal barrier is dependant upon the maintenance of the epithelial cell interactions with apical junctional complexes and the underlying basement membrane. These interactions have been shown to be compromised in intestinal infections as well as in chronic inflammatory states, such as inflammatory bowel disease. Previous work by other laboratories demonstrate [sic] the intestinal barrier function can be altered by inflammatory cytokines, as shown by decreases in transepithelial resistance. The exact mechanism by which these inflammatory cytokines influence the intestinal barrier is unknown. Our preliminary data implicates matrix metalloproteinase-7 (matrilysin) in the pathogenesis of inflammatory cytokine-induced altered barrier resistance. Matrilysin gene transcription as well as protein production, secretion and activation are increased in response to inflammatory cytokines. Basolateral treatment with activated matrilysin results in increased barrier permeability in cultured colonic epithelial cell lines. Our hypothesis is that matrilysin influences colonic epithelial barrer [sic] function through cleaving basolaterally-located apical junction complex proteins and disrupting basement membrane adherence and its regulation by inflammatory cytokines plays a role in the onset of acute and chronic colitis. Three specific aims will address the above hypothesis. First, we will elucidate the mechanism by which matrilysin regulates the shedding of extracellular components of apical junctional complex proteins and basement membrane adhesion proteins. Second, we will examine the inflammatory cytokine-induced regulation of matrilysin transcription. Third, we will determine whether matrilysin plays a key role in the onset of murine models of inflammatory bowel disease and infectious colitis. These studies will increase our understanding of the mechanism by which the intestinal epithelial cells maintain the barrier protecting the intestine from luminal contents both in tissue culture models and animal models of wound healing, infectious colitis and inflammatory bowel disease. These studies will also determine the mechanisms by which inflammatory cytokines regulate matrilysin gene expression.