Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, PR China.
Core Laboratory, School of Medicine, Sichuan Provincial People's Hospital Affiliated to University of Electronic Science and Technology of China, Chengdu, 610072, PR China.
Biochem Biophys Res Commun. 2020 Mar 26;524(1):36-42. doi: 10.1016/j.bbrc.2020.01.007. Epub 2020 Jan 21.
Gastric epithelial cells (GES-1) stimulated by Helicobacter pylori (H. pylori) would affect the expression of related genes and induce the immune response of the cells. Abnormal methylation of DNA was one of the main causes. The aim of this study was to investigate phosphoinositol-3-kinase adaptor protein 1(PIK3AP1), which was screened from the chip data as an immune gene candidate to against the inflammatory response of cells caused by H. pylori infection. PIK3AP1 plays a key role in PI3K/AKT signaling pathway. The gene chip analysis and experimental results confirmed that PIK3AP1 expression was downregulated and PIK3AP1 promoter was hypermethylated after H. pylori stimulation in GES-1 cells. Meanwhile, the expression level of PIK3AP1 was significantly upregulated after 5-aza-dc treatment, and its expression was higher after 5-aza-dc and H. pylori co-treatment than that of H. pylori treatment but lower than that of 5-aza-dc treatment. Therefore, hypermethylation was the main reason for the down-regulation of PIK3AP1 after H. pylori stimulation. In addition, the intervention of PIK3AP1 inhibited the expression of downstream gene AKT, and suppressing the expression of the immunoinflammatory gene IL-6 in GES-1 cells. Furthermore, the intervention of PIK3AP1 would promote cell proliferation. In summary, hypermethylation of the PIK3AP1 promoter was accompanied by reduction of the expression level of PIK3AP1 in GES-1 cells by H. pylori stimulation. The expression of PIK3AP1, AKT, and IL-6 genes was positively correlated, Meanwhile, the PIK3AP1 can affect the proliferation of GES-1 cells. These results would be helpful to understand the innate immune response function of PIK3AP1 to pathogenic bacterial infection in the stomach.
幽门螺杆菌（H. pylori）刺激胃上皮细胞（GES-1）会影响相关基因的表达，并诱导细胞的免疫反应。DNA 异常甲基化是主要原因之一。本研究旨在探讨从芯片数据中筛选出的免疫基因候选物磷酸肌醇-3-激酶衔接蛋白 1（PIK3AP1），以对抗 H. pylori 感染引起的细胞炎症反应。PIK3AP1 在 PI3K/AKT 信号通路中发挥关键作用。基因芯片分析和实验结果证实，H. pylori 刺激 GES-1 细胞后，PIK3AP1 表达下调，PIK3AP1 启动子超甲基化。同时，5-氮杂-2′-脱氧胞苷（5-aza-dc）处理后 PIK3AP1 表达水平显著上调，5-aza-dc 与 H. pylori 共同处理后表达高于 H. pylori 处理，但低于 5-aza-dc 处理。因此，H. pylori 刺激后 PIK3AP1 下调的主要原因是其启动子超甲基化。此外，PIK3AP1 的干预抑制了下游基因 AKT 的表达，并抑制了 GES-1 细胞中免疫炎性基因 IL-6 的表达。此外，PIK3AP1 的干预会促进细胞增殖。综上所述，H. pylori 刺激可导致 GES-1 细胞 PIK3AP1 启动子甲基化，PIK3AP1 表达水平降低。PIK3AP1、AKT 和 IL-6 基因的表达呈正相关，同时，PIK3AP1 可影响 GES-1 细胞的增殖。这些结果有助于理解 PIK3AP1 在胃中对致病菌感染的固有免疫反应功能。
