幽门螺杆菌对NLRP3炎症小体的活化作用

Effect of Helicobacter pylori infection on NLRP3 inflammasome activation

目的研究幽门螺杆菌(Helicobacter pylori,H.pylori)感染对NLRP3炎症小体相关蛋白的活化作用,探讨NLRP3炎症小体在H.pylori感染中的作用。方法培养H.pylori国际标准株NCTC11639,感染胃黏膜上皮细胞株GES-1和胃癌细胞株MKN-45,细菌数∶细胞数(感染复数)为100∶1和200∶1,于6 h和12 h收集细胞,提取总蛋白。Western blotting检测炎症小体中NLRP3及Caspase-1蛋白的表达水平,ELISA法检测细胞中IL-1β的含量。结果 H.pylori感染GES-1细胞后,NLRP3、Caspase-1以及IL-1β的表达随着感染复数的增加而增加,差异均具有统计学意义(P<0.05);感染MKN-45细胞后,NLRP3的蛋白表达随着感染复数的增加而增加,而Caspase-1及IL-1β的表达随着感染复数的增加而降低,差异均有统计学意义(P<0.05);相同感染复数的H.pylori感染GES-1细胞和MKN-45细胞,6 h和12 h之间NLRP3、Caspase-1以及IL-1β的表达差异均无统计学意义(P>0.05)。结论 H.pylori感染在体外能活化GES-1细胞中NLRP3炎症小体相关蛋白NLRP3和Caspase-1,活化MKN-45细胞中NLRP3蛋白的表达,抑制Caspase-1蛋白的表达;促进上皮细胞GES-1中IL-1β炎症因子的表达,抑制肿瘤细胞MKN-45中IL-1β炎症因子的表达。

Objective To study the impact of Helicobacter pylori（ H. pylori） infection on NLRP3 inflammasome associated proteins expression and activation in gastric epithelial cells and gastric cancer cells,and further discuss the role of NLRP3 inflammasome when gastric cells were infected by H. pylori. Methods The gastric epithelial cell line GES-1and gastric cancer cell line MKN-45 were infected by H. pylori NCTC11639 at a multiplicity of infection（ MOI） of 100 or 200. At 6 h or 12 h after infection,the cells were harvested and the total proteins were extracted. Then the expressions of NLRP3 and Caspase-1 were analyzed by Western blotting and the level of IL-1β secretion was detected by ELISA. Results The expressions of NLRP3 and Caspase-1 and the secretion of IL-1β were increased with the increase of NCTC11639 MOI in GES-1 cells（ P〈0. 05）. Although the expression of NLRP3 was increased,the expression of Caspase-1 and the secretion of IL-1β were decreased with the increase of NCTC11639 MOI in MKN-45 cells（ P〈0. 05）. In addition,the expressions of NLRP3 and Caspase-1 and the secretion of IL-1β were not significantly different in GES-1 or MKN-45 infected by H. pylori for 6 h and 12 h with the same MOI（ P〉0. 05）. Conclusion H. pylori infection promotes the expressions and activations of NLRP3,Caspase-1 and IL-1β in gastric epithelial cells. However,H. pylori infection facilitates the expression of NLRP3 but inhibits the expressions and activations of Caspase-1 and IL-1β in gastric cancer cells.