TSC1控制紧密连接形成的作用和机制研究

紧密连接(TJ)是封闭上皮细胞间隙，建立独特内部环境并维持生命的重要屏障，其破坏可导致一系列TJ相关性疾病。然而，TJ形成的控制机制并不明确。本项目首次发现，作为雷帕霉素机制性靶蛋白 (mTOR)的关键上游抑制分子，TSC1在上皮细胞中定位于AJ/TJ处并结合TJ关键蛋白ZO-1及黏着连接(AJ)关键蛋白β-Catenin。我们又初步探寻了TSC1控制并整合AJ/TJ形成及功能的重要作用、机制、临床相关性。本项目拟结合肠上皮特异性和全身可诱导TSC1敲除小鼠、蛋白质复合物结构分析、多种TJ相关疾病的生物信息学和组织切片分析，从分子、细胞、整体水平深入研究肠上皮细胞中TSC1通过ZO-1/β-Catenin控制AJ/TJ形成的具体机制，并进一步探索此机制在其他关键器官中的普遍性。本研究有望拓展上皮屏障形成的基础理论，并为防治TJ相关性疾病提供重要的理论依据和新的药物靶点。

Tight junction (TJ) is absolutely required for mammals to maintain life, since it is a crucial barrier sealing the intercellular space of epithelial cells, establishing of a distinct internal environment, and resisting the invasion of pathogens. Consequently, the impairment of TJ is associated with a myriad of TJ-related diseases. However, the controlling mechanism underlying their assembly is currently unclear. We revealed for the first time that in epithelial cells, TSC1, a key upstream endogenous inhibitor of mechanistic target of rapamycin (mTOR), binds ZO-1, one of the core components of TJ, as well as β-Catenin, one of the core components of adherens junction (AJ). Additionally, we further analyzed the role, clinical relevance, and underlying mechanism of TSC1 in AJ/TJ formation. Based on these results, we plan to study the detailed mechanism by which TSC1 orchestrate TJ formation via ZO-1/β-Catenin, at the molecular, cellular, and whole-body level, through integrating information from intestine epithelia-specific or inducible whole-body ablation of TSC1 in mice, cellular and molecular assay, three-dimensional molecular docking of TSC1 to ZO-1/β-Catenin, as well as bioinformatic and histopathological analysis of various kinds of TJ-related diseases. In addition, we will further explore if this Tsc1-controlled AJ/TJ organization is a general mechanism in other vital organs. This project will expand the basic theory of the formation of mucosal barrier, providing a novel rationale as well as a new promising for prevention and treatment of TJ-related diseases.