HuR和CIRP通过竞争性调节Claudin1在溃疡性结肠炎中的作用

Ulcerative colitis is a chronic inflammation that results in abnormity of morphology and function in intestinal epithelial cells(EC). Claudins family plays a key role, leading to intestinal mucosal repair abnormalities and barrier dysfunction. Our preliminary experiment and previous studies show that the level of CIRP, HuR and Claudin 1 significantly increase in intestinal mucosal tissue of ulcerative colitis. CIRP and HuR can regulate the intestinal epithelium homeostasis, but the exact molecular mechanism of their roles in regulation of Claudin 1 expression and epithelial dysfunction haven’t been known yet. There are several computationally predicted hits of the CIRP and HuR motif in the mRNA of Claudin 1 proteins, suggesting that the Claudin 1 mRNA maybe the direct target of CIRP and HuR. First, we will elucidate the clinical relevance in CIRP、HuR and Claudin 1 in ulcerative colitis. Second, we will examine the effect that CIRP and HuR regulate the Claudin 1 thereby regulating intestinal epithelial morphology and function both in vitro and in vivo. We will explore the mechanism of CIRP and HuR regulating Claudin 1 using CoIP, immunofluorescence in situ hybridization analysis, cofocallaser scanning microscope and other experimental techniques. The successful completion of this project will help to improve therapeutic approaches for ulcerative colitis disease.

溃疡性结肠炎（UC）是在慢性炎症持续的刺激下肠粘膜上皮细胞（IEC）发生形态异常及功能受损, 封闭蛋白家族(Claudins)起关键作用，导致肠粘膜修复异常、屏障功能严重受损等。既往研究及预实验发现UC肠粘膜组织中HuR和CIRP及Claudin1均明显升高，HuR和CIRP能调节IEC稳态，而两者在UC中调节Claudin1表达及屏障功能的分子机制不明，序列分析提示Claudin1 mRNA上有多个潜在的HuR和CIRP结合位点。为此拟进行：大样本验证HuR和CIRP及Claudin1在UC的IEC中表达临床相关性；在细胞和动物水平验证HuR和CIRP通过调节Claudin1表达而调节IEC形态及功能；并利用CoIP和原位免疫荧光杂交、激光共聚焦显微镜等技术探索HuR和CIRP竞争性作用于Claudin1的分子机制，为寻找新的诊疗切入点奠定理论基础。

溃疡性结肠炎（UC）是炎症性肠病的一种，在慢性炎症持续的刺激下肠黏膜上皮细胞（IEC）发生形态异常及功能受损，紧密连接蛋白家族(Claudins)在其中起关键作用，导致肠黏膜修复异常、屏障功能严重受损等。本研究在UC患者、UC体外细胞模型以及UC小鼠模型中探讨RNA结合蛋白冷诱导RNA结合蛋白（CIRP）、人抗原R（HuR）及Claudin1对肠黏膜屏障功能的影响，以及探索CIRP及HuR调控Claudin1表达的分子机制。我们发现在UC患者、细胞和小鼠模型中观察到CIRP高表达，HuR和Claudin1低表达。CIRP、HuR和Claudin1的表达与UC患者的严重程度相关。CIRP与Claudin1呈负相关，HuR与Claudin1呈正相关。Claudin1可以被CIRP抑制，而被HuR增强。HuR和CIRP可以竞争性地结合Claudin1。HuR上调或CIRP下调促进肠细胞增殖，抑制细胞凋亡，改善肠细胞屏障功能损伤。体内实验证实，HuR过表达或CIRP敲除可改善UC小鼠肠黏膜屏障功能损伤。CIRP和HuR通过竞争性结合Claudin1 mRNA对UC的肠黏膜屏障功能产生关键作用。我们的研究有望为溃疡性结肠炎疾病活动度及分期的判断和评价治疗效果寻找新的分子靶标，提高患者的长期缓解水平，具有重要的社会意义。