CRF上调PDIA3介导CD8+T淋巴细胞活化在IBS内脏高敏感形成中的作用研究

The main pathophysiological feature of irritable bowel syndrome is visceral hypersensitivity, the mechanisms of which, however, still remain unknown. Our previous work found that stress can significantly induce high level of protein disulfide isomerase A3 (PDIA3) in the colonic mucosa in IBS rat model, further study identified the overexpression of PDIA3 were located in dendritic cells in the colon. Meanwhile, we have also found that exposure to corticotropin-releasing factor (CRF) could increased the capacity of DC to stimulate CD8+ T cell proliferation, which maybe involved in the phosphorylation of ERK1/2 and, subsequently, the overexpression of PDIA3. Thus, we hypothesized that CRF-ERK1/2 pathway may mediate the increased expression of PDIA3 in DC, and lead to the immune activation of CD8+ T cell, which may play a critical part in the generation of visceral hypersensitivity of IBS. In this study, first, by using the IBS patients/rats as the reasearch subjects as well as the isolated colonic DC in IBS rats, we try to clarify that the PDIA3 could enhance the ability of endogenous antigen presenting in DC, which lead to the immune activation of CD8+ T cell and the generation of visceral hypersensitivity of IBS. Second, using the CRF knock down rat and ERK1/2 antagonist, we try to further elucidate the mechanism that CRF-ERK1/2 pathway could mediate the overexpression of PDIA3. Therefore，our study aim to futher improve the mechanisms of stress related immune abnormity in IBS, and the final results of our research might provide new insights for the pathophysiology of IBS and clinical treatment.

肠易激综合征（IBS）内脏高敏感的原因尚不明确。前期研究发现应激IBS大鼠肠黏膜上调表达蛋白质二硫键异构酶A3 (PDIA3)，且其在应激大鼠肠道树突状细胞（DC）中高表达，而促肾上腺皮质激素释放因子（CRF）可以促进肠道DC刺激CD8+T淋巴细胞增殖，其可能与ERK1/2磷酸化导致PDIA3表达上调有关，因此，我们认为CRF-ERK1/2途径可以介导DC表达 PDIA3上调，通过引起CD8+T淋巴细胞免疫活化而导致IBS内脏高敏感。本研究首先以IBS患者/大鼠为研究对象，明确PDIA3增强DC内源性抗原提呈能力，导致CD8+T淋巴细胞免疫应答活化和内脏高敏感的作用机制，其次，通过构建CRF基因沉默大鼠及采用ERK1/2拮抗剂，阐明CRF-ERK1/2通路活化上调PDIA3的表达水平的机制。通过本研究将进一步完善IBS应激相关肠道免疫调控异常的机制研究并为寻求临床治疗的新靶点提供依据。

内脏高敏感是肠易激综合征（IBS）核心机制, 其产生原因未清楚阐明。我们前期工作发现应激IBS大鼠结肠黏膜上调表达蛋白质二硫键异构酶A3 (PDIA3)，进一步研究发现其在应激IBS大鼠肠道树突状细胞（DC）中高表达，而促肾上腺皮质激素释放因子（CRF）可以促进肠道DC刺激T淋巴细胞增殖，其可能与细胞外信号调节激酶1/2（ERK1/2）的磷酸化导致PDIA3表达上调有关，因此，我们认为CRF-ERK1/2途径可以介导DC表达 PDIA3上调，后者引起T淋巴细胞免疫活化，从而在IBS内脏高敏感中发挥作用。.本研究首先以IBS患者/大鼠为研究对象，通过分离大鼠肠道DC，明确PDIA3增强DC内源性抗原提呈能力，导致T淋巴细胞免疫活化和IBS内脏高敏感的作用机制，其次，构建CRF基因沉默大鼠及采用ERK1/2拮抗剂，进一步阐明CRF-ERK1/2信号通路活化上调PDIA3的表达水平，导致DC内源性抗原提呈能力增强和T淋巴细胞免疫应答激活的作用机制。本研究创新性发现，PDIA3可介导DC抗原提呈能力增加引起CD4+/CD8+T淋巴细胞免疫活化，通过介导肠道炎症，在IBS内脏高敏感产生中发挥作用；研究进一步发现，CRF通过活化ERK1/2信号通路，介导肠道DC上调表达PDIA3。.综上所述，本研究通过入组IBS患者、构建IBS动物模型、采用基因沉默技术，在细胞分子、蛋白及基因水平等方面对应激调控PDIA3与IBS肠道DC免疫的关系及其机制展开系列研究，通过本研究将进一步完善IBS应激相关肠道免疫调控异常的机制研究并为寻求临床治疗的新靶点提供依据。.本课题共协同培养硕士研究生1名，研究相关成果共发表相关论文3篇（国内核心期刊论文1篇）。曾受邀在过内各种学术交流会议上进行学术交流与分享，其中，2019年参加第五届中国医师协会中西医结合医师分会消化病中西医联合论坛暨脾胃病研究所论坛，受邀做汇报交流。