幽门螺杆菌调控胃粘膜上皮细胞PGRN表达的分子机制及其抗炎作用研究

Progranulin (PGRN) belongs to a novel class of growth facter that plays a antiinflammatory role in diverse tissue inflammation, but it is not known the relationship between PGRN and gastritis infected by Helicobacter pylori(H.pylori). Previously we found that infection of gastric epithelial cells with H.pylori significantly increased PGRN expression and knockdown of PGRN could obviously increase H.pylori infection-induced inflammatory COX-2 expression.On this basis, clinical specimen and experimental animal would be used to investigate the relationship between PGRN and H.pylori infection; signal inhibitors would be used to explore possible signaling pathways of PGRN induced by H.pylori infection; DNA deletion, reporter gene and luciferase activity would be used to decode the regulatory element; we would also detect the effect and molecular mechanism of knockdown or overexpression of PGRN on the induction of inflammatory molecules by H.pylory infection. This work could be useful to demonstrate the hypethesis that PGRN is an important defensive factor against chronic gastritis, investigate the effective regulatory factor in gastritis development caused by H. pylori infection,that could provide a new theory for the prognosis of gastritis.

Progranulin（PGRN）是一种新型生长因子，在多种组织炎症中发挥重要的抗炎作用，但与幽门螺杆菌（(H.pylori）感染性胃炎的关系仍不明确。申请者前期研究首次发现H.pylori能够诱导胃粘膜上皮细胞中PGRN分子的表达、抑制PGRN后H.pylori感染可以明显增强胃粘膜上皮细胞炎性因子COX-2的表达，本课题以此为依据利用临床标本、实验动物等进一步探讨H.pylor感染与PGRN的关系；并在此基础上利用信号转导途径抑制剂分析H.pylori调控PGRN表达的信号转导通路；利用DNA缺失、报道基因等解码H.pylori调节PGRN的调控元件；观察PGRN表达变化对H.pylori诱导胃粘膜上皮细胞炎性分子表达的影响及其分子机制，以论证PGRN是慢性胃炎的重要内源性防御因子的假说，寻找幽门螺杆菌感染致胃炎发生过程中能够有效调控的关键因素，为胃炎的的疾病转归提供新的理论依据。

幽门螺杆菌（Helicobacter pylori, Hp）是慢性胃炎和消化性溃疡的重要病因，与胃癌的发生密切相关，世界卫生组织国际癌症研究机构(IARC)已将幽门螺杆菌列为Ⅰ级致癌因子，然而幽门螺杆菌导致胃粘膜组织炎症，以及持续性炎症诱发恶性转化的机制有待进一步研究。.Progranulin (PGRN)，又称为颗粒体蛋白前体，PC cell–derived growth factor, proepithelin, or acrogranin, 属于一类新型的生长因子，它在发育、细胞周期进展、细胞运动及肿瘤形成发展中起到重要的作用。.一、幽门螺杆菌对胃粘膜上皮细胞PGRN表达的影响及其在增殖和迁徙中的作用.（1）PGRN在慢性胃炎、胃癌患者的胃组织中表达显著升高；（2）幽门螺杆菌感染胃粘膜上皮细胞后PGRN mRNA和蛋白水平均明显增高：（3）幽门螺杆菌感染胃粘膜上皮细胞上调PGRN不依赖于CagA、VacA、LPS等，只有活菌完整的接触胃粘膜上皮细胞才能影响PGRN的表达；（4）幽门螺杆菌感染诱导PGRN表达依赖于p38、MEK1/2信号途径；（5）PGRN参与幽门螺杆菌所促进的胃癌细胞的增殖和迁徙。.二、PGRN抑制幽门螺杆菌诱导胃粘膜上皮细胞COX-2的表达 .幽门螺杆菌感染感染小鼠胃粘膜组织中性粒细胞、嗜酸性粒细胞侵润，COX-2和PGRN的表达水平明显升高；细胞系水平也得到一致的结果并具有时间依赖性。胃粘膜上皮细胞过表达PGRN后能够抑制COX-2蛋白的表达、Iκbα的磷酸化以及NF-κB P65核转位。然而，运用RNAi技术抑制PGRN在胃粘膜上皮细胞的表达后再感染幽门螺杆菌，COX-2蛋白的表达、以及NFκB P65核转位却均升高。因此，PGRN是一个重要的炎症调节因子，通过抑制COX-2的表达发挥的抗炎作用。