IL-6 regulation of matrix degradation in liver fibrosis

描述（由申请人提供） 了解有利于再生而不是纤维化反应的机制 对于制定治疗和逆转慢性肝病的策略至关重要 疾病本申请涉及白细胞介素-6所起的核心作用， （IL-6）通过其对以下活动的影响来确定这一结果： 肝脏基质降解蛋白酶。IL-6-/-小鼠肝脏表现出增加的 急性和慢性创伤模型中的损伤、伤口愈合延迟和纤维化 毒素引起的损伤，这与增加 基质金属蛋白酶-2（MMP-2）表达。我们的数据表明，MMP-2是 促纤维化，不仅通过加速低密度的替代， 内皮下基质和富含I型胶原的瘢痕样间质基质 胶原蛋白，而且还通过其降解膜1型基质的能力 金属蛋白酶（MT 1-MMP），一种有效的I型胶原酶。另外我们 结果表明，α 2-巨球蛋白的不适当下调， IL-6调节基因，在增加细胞的净活性中起关键作用。 MMP-2在体内的表达，并有助于增加损伤和纤维化， IL-6-/-肝。我们假设IL-6是肝脏中的关键细胞因子， 通过在基因水平下调MMP-2活性来促进伤口愈合 潜在酶的表达、激活和/或活性酶的抑制。 本申请的具体目的是：（1）表征 IL-6调节MMP-2表达和/或活化;（2）确定 MMP-2活化的增加是否导致I型胶原蛋白的减少 由于MT 1-MMP的水平/活性降低而导致的降解;（3）评估MT 1-MMP的作用 α_2-巨球蛋白在体内抑制MMP-2的作用 MMP-2抑制剂对IL 6 +/+肝损伤的影响 和-/-小鼠急性和慢性肝损伤。这些相互关联的具体 将主要使用CC 14诱导的急性和慢性炎症模型来探索目的。 肝损伤和来自IL-6+/+和IL-6-/-肝的原代星状细胞培养物。 免疫印迹分析、北方印迹分析、核连续试验、启动子 分析，明胶酶谱，和免疫共沉淀将被用来 研究这些目标的具体方面。总的来说，这一总体目标 目的是阐明白细胞介素-6在调节肝脏功能中的作用 损伤和纤维化。了解这些 其机制将为开发新型抗纤维化药物提供基础。 治疗广泛流行的疾病的治疗方法， 治疗至今。

DESCRIPTION (provided by applicant) Understanding mechanisms that favor regenerative rather than fibrotic responses is essential to developing strategies for treating and reversing chronic liver disease. This application addresses the central role played by interleukin-6 (IL-6) in determining this outcome through its effects on the activity of matrix degrading proteases in liver. IL-6-/-mouse livers exhibit increased injury, delayed wound healing, and fibrosis in models of acute and chronic toxin-induced injury, which correlates with increased matrix-metalloproteinase-2 (MMP-2) expression. Our data suggest that MMP-2 is profibrogenic, not only by hastening the replacement of the low density subendothelial matrix with a scar-like interstitial matrix rich in type I collagen, but also by its ability to degrade membrane type-1 matrix metalloproteinase (MT1-MMP), a potent type I collagenase. In addition, our results indicate that inappropriate downregulation of alpha2-macroglobulin, an IL-6 regulated gene, plays a critical role in increasing the net activity of MMP-2 in vivo and contributes to the increased injury and fibrosis in IL-6-/-livers. We hypothesize that IL-6 is a critical cytokine in the hepatic wound healing response by downregulating MMP-2 activity at the level of gene expression, activation of latent enzyme, and/or inhibition of active enzyme. The Specific Aims of this application are: (1) To characterize the level(s) at which IL-6 regulates MMP-2 expression and/or activation; (2) To determine whether increased activation of MMP-2 leads to decreased collagen type I degradation due to reduced levels/activity of MT1-MMP; (3) To assess the role of alpha2-macroglobulin in inhibiting MMP-2 in vivo; (4) To test the importance of MMP-2 in liver injury in vivo by administering MMP-2 inhibitors to IL6 +/+ and-/-mice with acute and chronic liver injury. These interrelated Specific Aims will be explored primarily using CC14 induced models of acute and chronic liver injury and primary stellate cell culture from IL-6+/+ and IL-6-/-livers. Immunoblot analysis, northern blot analysis, nuclear run-on assays, promoter analysis, gelatin zymography, and co-immunoprecipitation will be utilized to study specific aspects of these aims. In summary, the overall goal of this application is to elucidate the role of interleukin-6 in regulating liver injury and fibrosis via its effects on matrix degradation. Understanding these mechanisms will provide the basis for the development of novel anti-fibrotic therapies to treat a widely prevalent disease for which there is no effective treatment to date.