Helicobacter pylori Infection Activates the Akt-Mdm2-p53 Signaling Pathway in Gastric Epithelial Cells
Helicobacter pylori Infection Activates the Akt-Mdm2-p53 Signaling Pathway in Gastric Epithelial Cells
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DOI：
10.1007/s10620-014-3470-2
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发表时间：
2015-04-01
影响因子：
3.1
通讯作者：
Lu, Nong-Hua
中科院分区：
文献类型：
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作者：
Shu, Xu;Yang, Zhen;Lu, Nong-Hua
背景和目的虽然幽门螺杆菌被广泛认为是许多胃疾病的致病因素，但幽门螺杆菌对信号通路的影响尚不清楚。pylori感染以及随后对细胞凋亡和增殖的影响仍不清楚。在这里，我们研究了介导H.方法对160例胃粘膜上皮细胞中H. pylori感染，并通过免疫组织化学分析Akt、pAkt、Mdm 2、p53和Bax表达。体外培养的人胃上皮细胞GES-1与H.幽门螺杆菌培养MTT法检测细胞活力。Annexin V/PI双染后流式细胞术、DNA电泳和彗星试验检测细胞凋亡。采用RT-PCR和Western blot方法检测H. pylori感染与慢性非萎缩性胃炎（CNAG）中pAkt、异型增生中Mdm 2、化生性萎缩（MA）中p53以及CNAG和MA中Bax水平显著升高相关。在体外，H. pylori培养物E2以时间和剂量依赖性方式降低GES-1细胞活力，诱导G 0/G1期阻滞，触发凋亡，并增加DNA片段化。H处理后，Mdm 2和Bax mRNA表达及pAkt、Mdm 2、p53和Bax蛋白表达均显著上调。幽门螺杆菌培养LY 294002抑制Akt可降低Mdm 2表达，上调p53，增强H.结论Akt-Mdm 2-p53信号通路参与了GES-1细胞对H. pylori的分子应答。幽门感染
Backgrounds and Aims Although Helicobacter pylori is widely accepted as a causative factor of many gastric diseases, the signaling pathways affected by H. pylori and subsequent effects on cell apoptosis and proliferation remain unclear. Here, we investigated the molecular mechanisms mediating H. pylori infection in gastric epithelial cells.Methods Tissues from 160 patients with various gastric diseases with or without H. pylori infection were obtained and analyzed by immunohistochemistry for Akt, pAkt, Mdm2, p53, and Bax expression. In vitro, human gastric epithelial cells, GES-1, were incubated with H. pylori culture filtrates. Cell viability was measured by MTT assay. Apoptosis was evaluated by Annexin V/PI double staining followed by flow cytometry, DNA electrophoresis, and comet assay. mRNA and protein expression was assessed by RT-PCR and Western blot analysis.Results In patient tissues, H. pylori infection was associated with significantly elevated levels of pAkt in chronic nonatrophic gastritis (CNAG), Mdm2 in dysplasia, p53 in metaplastic atrophy (MA), and Bax in CNAG and MA. In vitro, H. pylori culture filtrates reduced GES-1 cell viability in a time-and dose-dependent manner, induced G0/G1 arrest, triggered apoptosis, and increased DNA fragmentation. Mdm2 and Bax mRNA expression and pAkt, Mdm2, p53, and Bax protein expression were significantly upregulated when treated with H. pylori culture filtrates. Akt inhibition by LY294002 decreased Mdm2 expression, upregulated p53, and enhanced H. pylori-induced growth inhibition of GES-1 cells.Conclusions These findings suggest that Akt-Mdm2-p53 signaling is involved in the molecular response of GES-1 cells to H. pylori infection.