Microbiota in Intestinal Fibrosis

项目摘要 该项目提出了一个全面的五年指导研究发展计划，过渡到 独立该研究计划调查严重的临床问题肠纤维化和狭窄 炎症性肠病（IBD）的形成。它探讨了一个全新的概念， 细菌成分对肠间充质细胞，主要的促纤维化细胞类型，在体外和体内。我们 发现人肠肌成纤维细胞对细菌感知模式识别的激活作出反应 受体，但只有鞭毛蛋白增加分泌的细胞外基质（ECM）成分纤连蛋白和 胶原蛋白1。这种反应是转录后调节的，并依赖于半胱天冬酶1，暗示了 肠纤维化中的炎性小体。因此，我们建议探讨以下假设：肠道 微生物群通过鞭毛蛋白介导的途径诱导肠纤维化。这一假设将是 通过三个相互关联但独立的具体目标进行测试：（1）确定鞭毛蛋白的机制- 体外诱导ECM分泌的转录后调节（2）以确定鞭毛蛋白的作用 在原代人间充质干细胞促纤维化反应中介导的炎性小体活化 （3）探讨消除鞭毛蛋白信号在实验性纤维化中的作用， 在诱导和解决肠纤维化的过程中体内。转录后调节和 通过半胱天冬酶1的炎性小体活化是肠纤维化的两种完全原始的机制。我们将使用一个 尖端的转基因小鼠模型，允许控制体内细菌传感缺失的时间 尤其是间充质细胞。这使得能够探索微生物传感在预防和 肠纤维化的消退。这项研究将在勒纳博士的实验室进行 研究所（LRI），克利夫兰诊所，并将由一个国际专家小组在人类和 实验性纤维形成、翻译调节和微生物群。顾问小组已制订一套 结构化的职业发展计划，包括微生物学的正式课程，转化调节 和统计数据。理想的知识和技术环境在LRI当地到位。我的职业目标是 建立和领导一个独立的研究计划，将推进科学知识和病人护理， 肠纤维化领域。我之前在原代人类细胞系统和动物模型方面的经验让我 成为成功的K 08获奖者的理想基础。这项研究将为直接的证据提供新的证据。 肠道间充质细胞中的微生物群诱导纤维化和狭窄形成的作用。这些 这些发现可能会导致一种全新的方法，将微生物群作为治疗策略， 消除纤维化。

PROJECT SUMMARY This project proposes a comprehensive five-year mentored research development program with transition to independence. The research plan investigates the severe clinical problem of intestinal fibrosis and stricture formation in inflammatory bowel diseases (IBD). It explores the entirely novel concept of a direct effect of bacterial components on intestinal mesenchymal cells, the chief pro-fibrotic cell type, in vitro and in vivo. We found that human intestinal myofibroblasts respond to activation of bacterial sensing pattern recognition receptors, but only flagellin increases secretion of the extracellular matrix (ECM) components fibronectin and collagen 1. This response is post-transcriptionally regulated and dependent on caspase 1, implicating the inflammasome in intestinal fibrosis. Therefore, we propose to explore the following hypothesis: the gut microbiota induces intestinal fibrosis through a flagellin mediated pathway. This hypothesis will be tested through three interrelated, but indepedent specific aims: (1) to define the mechanisms of flagellin- induced post-transcriptional regulation of ECM secretion in vitro (2) to determine the role of flagellin mediated inflammasome activation in the pro-fibrogenic responses in primary human mesenchymal cells in vitro and (3) to explore the effect of abrogating flagellin signaling in experimental fibrosis in vivo during induction and resolution of intestinal fibrosis. Post-transcriptional regulation and inflammasome activation via caspase 1 are two entirely original mechanisms of intestinal fibrosis. We will use a cutting edge transgenic mouse model that allows control of the timing of deletion of bacterial sensing in vivo specifically in mesenchymal cells. This enables exploration of microbial sensing in the prevention and resolution of intestinal fibrosis. The research will be carried out in the laboratory of Dr. Fiocchi MD, Lerner Research Institute (LRI), Cleveland Clinic, and will be advised by a panel of international experts in human and experimental fibrogenesis, translational regulation and the microbiota. The advisory panel has worked out a structured career development program, including formal coursework in microbiology, translational regulation and statistics. An ideal intellectual and technical environment is in place locally in the LRI. My career goal is to build and lead an independent research program that will advance scientific knowledge and patient care in the field of intestinal fibrosis. My prior experience with primary human cell systems and animal models gives me the ideal basis to be a successful K08 awardee. The proposed study will provide novel evidence for the direct effect of the microbiota in intestinal mesenchymal cell induced fibrogenesis and stricture formation. These findings could lead to a completely novel approach of targeting the microbiota as a therapeutic strategy to abrogate fibrosis.