IL-6 regulation of matrix degradation in liver fibrosis

描述(由申请人提供) 理解有利于再生反应而不是纤维化反应的机制 对于制定治疗和逆转慢性肝脏的策略是必不可少的 疾病。该应用程序解决了白细胞介素6所起的核心作用 (IL-6)通过其对活动的影响来决定这一结果 肝脏中的基质降解酶。IL-6-/-小鼠肝脏表现出增加 急性和慢性模型中的损伤、伤口愈合延迟和纤维化 毒素诱导的损伤，这与增加 基质金属蛋白酶-2(MMP2)的表达。我们的数据表明，基质金属蛋白酶-2 促纤维化，不仅通过加速低密度的更替 具有富含I型瘢痕样间质基质的内皮下基质 胶原蛋白，但也与其降解1型膜基质的能力有关 金属蛋白酶(MT1-MMPs)，一种有效的I型胶原酶。此外，我们的 结果表明，α2-巨球蛋白的不适当下调，以及 IL-6调节基因，在增加细胞净活性中起关键作用 体内的基质金属蛋白酶-2，并在增加损伤和纤维化中起作用。 IL-6-/-肝脏。我们假设IL-6是肝脏中的一种关键细胞因子 在基因水平下调基质金属蛋白酶-2活性对创伤愈合的影响 潜伏酶的表达、激活和/或活性酶的抑制。 本申请的具体目的是：(1)表征(S)在 哪个IL-6调节基质金属蛋白酶-2的表达和/或激活；(2)确定 基质金属蛋白酶-2活性增加是否导致I型胶原减少 由于MT1-基质金属蛋白酶水平/活性降低而引起的降解；(3)评估其作用 α2-巨球蛋白在体内抑制基质金属蛋白酶-2的作用；(4)检测其重要性 IL-6+/+细胞给予基质金属蛋白酶-2抑制剂对肝损伤中基质金属蛋白酶-2的影响 和-/-有急性和慢性肝损伤的小鼠。这些相互关联的特定 将主要使用CC14诱导的急性和慢性模型来探索AIMS 肝损伤及IL-6+/+和IL-6-/-肝原代星状细胞培养。 免疫印迹分析、Northern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用于 研究这些目标的具体方面。总而言之，这一总体目标是 白介素6在肝脏调节中的应用 损伤和纤维化通过其对基质降解的影响。了解这些 其作用机制将为新型抗纤维化药物的开发提供基础 治疗一种广泛流行但没有疗效的疾病的疗法 到目前为止的治疗。

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.