功能性消化不良全新的发病机制：肥大细胞通过PAR-2调控ERK1/2通路致十二指肠上皮屏障功能受损

Functional dyspepsia (FD) is a chronic disease with high prevalence, which can seriously impact health-related quality of life. At present, the treatment effect of FD is not satisfactory. Therefore, it is an important issue to explore its new pathogenic mechanism and find effective treatment. Study showed that the impairment of duodenal epithelial barrier function are closely related to the occurrence of FD. Previous studies confirmed that both the sum of mast cell and the number of degranulated mast cell in the duodenal mucosa of patients with FD are significantly higher compared with control. Our preliminary research discovered the loss of epithelial junctional complex proteins in duodenal biopsies from patients with FD. Therefore, we speculate that mast cells release tryptase and regulate the signaling pathway of extracellular signal regulated kinase 1/2 (ERK1/2) through the PAR-2 receptor, leading to the loss expression of epithelial junctional complex in the duodenal epithelium and the impairment of duodenal epithelial barrier function. By using various techniques, such as immunohistochemistry, real-time PCR, Western blot, immunofluorescence, etc., this project investigates whether patients with FD have the impairment of duodenal epithelial barrier function and its mechanism from two respects: one is 3D model of intestinal epithelium in vitro as well as the co-culture of mast cells and intestinal epithelial cells in vitro; the other is a clinical research. It will provide a new idea for exploring the pathogenesis of FD and a wholly new approach for the clinical prevention and treatment of FD.

功能性消化不良（FD）一个高度流行且严重影响生命质量的慢性疾病。目前FD的治疗效果不尽人意。因此，探索FD新的发病机制，找到有效的治疗方案是FD目前面临的重要课题。研究显示，十二指肠上皮细胞屏障功能破坏与FD的发生密切相关。既往文献证实FD患者十二指肠粘膜中肥大细胞总数及脱颗粒的肥大细胞数明显增高。我们前期研究发现，FD患者十二指肠粘膜组织细胞连接蛋白的表达缺失。故我们推测：肥大细胞释放类胰蛋白酶，通过PAR-2受体调控ERK1/2信号通路，导致十二指肠上皮细胞连接蛋白的表达缺失，进而导致十二指上皮屏障功能受损。本研究采用免疫组化，R-T-PCR, Western blot及免疫荧光等技术，从体外三维肠上皮模型，共培养肥大细胞及肠上皮细胞，及临床研究二个层面探讨FD患者是否存在十二指肠上皮屏障功能受损及其机制。本项目会为FD的发病机制提供新的思路，为FD的临床防治开辟一条全新的途径。

功能性消化不良（FD）是一个高度流行并且严重影响生命质量的慢性疾病，是当前严重影响我国人民身体健康和社会发展的重要疾患。目前治疗FD的常用药物及治疗方法效果不尽人意，因此，探索FD新的发病机制，找到有效的防治方案是FD目前面临的重要课题。. 本研究从体外细胞培养建立体外三维肠上皮模型，体外共培养肥大细胞及小肠上皮细胞及临床研究二个层面探讨FD患者是否存在十二指肠上皮细胞屏障功能受损及其机制。共培养肥大细胞及小肠上皮细胞，采用免疫组化，R-T-PCR，Western blot及免疫荧光等技术，应用肥大细胞稳定剂，类蛋白酶，类胰蛋白酶抑制剂，PAR-2受体激活肽，PAR-2受体拮抗剂及信号通路抑制剂等试剂，分析该过程中小肠上皮细胞的PAR-2受体及细胞连接蛋白的表达变化；最后探讨FD患者和健康志愿者十二指肠活检组织中肥大细胞浸润活化，细胞连接蛋白及PAR-2受体表达，进行组间对比分析，并评估Glasgow消化不良严重程度及FD亚型与细胞连接蛋白的表达水平及肥大细胞浸润程度之间的关系。. 我们临床及基础研究结果表明，患者十二指肠粘膜组织紧密连接蛋白claudin8表达显著低于健康志愿者。因此，十二指肠上皮细胞的细胞连接蛋白的表达缺失可能是FD一个新的发病机制，可能成为FD新的临床防治方法。