肾上腺髓质素在幽门螺杆菌感染中的表达调控及其功能的初步研究

目的 探讨肾上腺髓质素(adrenomedullin,ADM)在幽门螺杆菌感染中的表达调控及其对CD3+T细胞增殖的影响.方法 建立幽门螺杆菌(Helicobacter pylori,H.pylori)感染C57小鼠及胃上皮细胞模型,运用定量PCR、免疫组织化学染色和Western blot检测ADM的表达;并在细胞模型中探讨H.pylori感染诱导ADM上调的机制;利用ADM刺激CD3+T细胞,检测其对T细胞增殖的影响.结果 H.pylori感染可诱导胃上皮细胞AGS和HGC-27上调ADM的表达,并具有时间和感染菌量依赖性(P＜0.05);PI3 K/AKT信号通路阻断可显著抑制H.pylori感染诱导的ADM上调表达(P＜0.05);相对于未感染组,H.pylori感染小鼠胃组织中的ADM水平也显著增高;而相对于野生型全毒株,敲除cagA基因后,H.pylori感染诱导ADM上调的能力则显著下降(P ＜0.05);ADM能够以剂量依赖的方式诱导CD3+T细胞的增殖并促进IFN-y的表达(P＜0.05).结论 幽门螺杆菌感染可经PI3K/AKT信号诱导肾上腺髓质素的表达上调,后者则可能通过影响CD3+T细胞的增殖和分化而发挥免疫调节作用.

Role and mechanism of adrenomedullin expression in Helicobacter pylori infection

Objective To explore the expression regulation of adrenomedullin (ADM) in Helicobacter pylori (H.pylori) infection and its effect on the proliferation of CD3 + T cells.Methods H.pylori infection model was established in C57 mice and gastric epithelial cell lines (AGS and HGC-27).RT-PCR was used to detect the expression of ADM in the cells incubated with or without H.pylori.The protein levels of ADM,AKT and p-AKT were detected by Western blotting.The function of ADM on the proliferation of CD3 + T cells were evaluated by flow cytometry.Results H.pylori infection increased the expression of ADM in AGS cells and HGC-27 cells in a time-and dose-dependent manner (P ＜ 0.05).While,blocking PI3K/AKT signal pathway reversed above increase induced by H.pylori (P ＜ 0.05).Compared with uninfected mice,the infection also enhanced the ADM expression in the mouse gastric tissue.Compared with WT H.pylori infected AGS and HGC-27 cells,knockout of cagA resulted in decrease in ADM expression which was induced by H.pylori infection (P ＜ 0.05).ADM induced the proliferation of CD3 + T cells in a dose-dependent manner,and enhanced the expression of IFN-γ (P ＜ 0.05).Conclusion H.pylori infection up-regulates ADM expression through PI3K/AKT signaling pathway activation,and ADM exerts immunoregulatory effect by promoting proliferation and IFN-γproduction of CD3 + T cells.