膜蛋白CMTM4在胃黏膜致病过程中的作用及机制研究

Gastric mucosal diseases seriously affect people's health and quality of life. Studying on the pathogenesis is helpful for effective prevention and treatment of gastric mucosal diseases. CMTM family, as a membrane vesicular transport-related protein, may be involved in regulating immune function and diseases occurrence. Our previous studies showed that CMTM4 expression was down-regulated after helicobacter pylori (Hp) infection. CMTM4 was down-regulated in gastric cancer tissues, and the expression level of CMTM4 was positively correlated with the prognosis of gastric cancer. In this project, we will further research on CMTM4 by intervening CMTM4 expression in cell experiment, followed by detecting gastric mucosa cell proliferation, apoptosis, migration infected with Hp, measuring inflammatory cytokines expression, and exploring the downstream molecular mechanisms of CMTM4 by proteomic analysis. The cmtm4 gene knockout mice model of spontaneous gastric mucosal disease will be established, and the effects of CMTM4 expression on the development of gastric mucosal disease will be evaluated, and proteomic analysis will be performed on animal tissues. In clinical tissues, the relationship between CMTM4 and its downstream molecules expression and clinical data such as gastric mucosal disease type and Hp infection will be analyzed. This project will reveal the roles and mechanisms of CMTM4 in the pathogenesis of gastric mucosa, and provide theoretical basis on identifying new targets for prevention, early diagnosis and treatment of gastric mucosa diseases, especially gastric cancer.

胃黏膜疾病严重影响人们的健康及生活质量，对其发病机制进行研究有助于疾病的有效防治。CMTM家族作为一种膜泡运输相关蛋白，与机体免疫功能调节和疾病发生可能相关。我们前期研究发现，幽门螺杆菌（Hp）感染后CMTM4表达下调；CMTM4在胃癌组织中表达下调，CMTM4的表达水平与胃癌预后存在显著正相关。本项目将进一步通过细胞实验干预CMTM4表达，检测Hp感染胃黏膜细胞的增殖、凋亡、迁移以及炎性细胞因子的表达，用蛋白质组学方法探索CMTM4下游分子机制；构建Cmtm4基因敲除小鼠自发胃黏膜疾病模型，评价CMTM4表达对胃黏膜疾病发生发展的影响，用蛋白质组学方法进一步探索CMTM4的作用机制；利用临床组织分析CMTM4及其下游分子表达与胃黏膜疾病类型、Hp感染等临床资料的相关性。以揭示CMTM4在胃黏膜致病过程中的作用及机制，为有效防治胃黏膜疾病、寻找阻断胃癌发生的新靶点提供理论依据。

CMTM4在机体免疫功能调节中发挥重要作用，并参与肿瘤的形成与进展，但其在胃粘膜相关疾病中的作用和机制尚不明确。我们前期研究发现幽门螺杆菌（HP）感染后CMTM4表达下调；CMTM4在胃癌中表达下调，其表达水平与胃癌预后显著正相关。本研究在此基础上，通过HP与胃上皮细胞共培养及临床标本分析了HP对CMTM4表达的影响；检测了CMTM4对HP感染胃上皮细胞的增殖、凋亡及炎症因子表达的影响；利用Cmtm4基因敲除小鼠构建HP诱导的小鼠胃黏膜疾病模型，评价CMTM4对小鼠胃黏膜疾病发生发展的影响。结果显示，CMTM4在HP感染的胃上皮细胞中表达降低，HP阳性的慢性胃炎患者胃粘膜CMTM4表达水平低于HP阴性患者，提示CMTM4参与了HP致胃粘膜疾病的过程。CMTM4可抑制HP感染的胃黏膜上皮细胞增殖并促进IL-6的表达，而对其凋亡无明显影响。小鼠模型中，Cmtm4敲除组在HP感染3个月时 HP定植以及免疫细胞浸润显著低于对照组，更长时间（8、12、16、24个月）的小鼠模型病理分析结果显示Cmtm4敲除小鼠胃黏膜病理组织评分均低于对照组，提示Cmtm4敲除减轻了HP引起的炎症反应及胃黏膜损伤。此外，Cmtm4敲除组小鼠胃癌发生率显著低于对照组。以上结果提示CMTM4可促进HP感染引发的胃黏膜疾病的发生发展。.此外，为了探究CMTM4在胃癌细胞中的作用，我们构建了CMTM4过表达及敲减的胃癌细胞系，分析了CMTM4对胃癌细胞的增殖、凋亡、迁移及侵袭的影响，并用蛋白质组学方法探索CMTM4下游分子机制。结果显示， CMTM4显著抑制了AGS细胞的增殖、迁移和侵袭，促进了细胞凋亡。利用TMT蛋白质组测序分析CMTM4过表达与对照组之间的差异表达蛋白，发现CMTM4可能主要通过NF-kappaB及JAK-STAT信号通路影响胃癌细胞的生长、迁移和侵袭。本研究显示CMTM4可能通过促进HP引起的炎症反应进而促进胃黏膜疾病的发生发展。而在胃癌细胞中，CMTM4可能通过NF-kappaB和JAK-STAT信号通路影响胃癌细胞的生长及迁移、侵袭。本项目系统阐释了CMTM4在HP致胃黏膜疾病及胃癌中的功能，有助于明确胃癌的发病机制，并为有效防治胃黏膜疾病、寻找阻断胃癌发生的新靶点提供理论依据。