Helicobacter pylori Initiates a Mesenchymal Transition through ZEB1 in Gastric Epithelial Cells
Helicobacter pylori Initiates a Mesenchymal Transition through ZEB1 in Gastric Epithelial Cells
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DOI：
10.1371/journal.pone.0060315
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发表时间：
2013-04-02
期刊：
影响因子：
3.7
通讯作者：
Staedel, Cathy
中科院分区：
文献类型：
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作者：
Baud, Jessica;Varon, Christine;Staedel, Cathy
慢性幽门螺杆菌感染引起胃粘膜炎症，具有溃疡和癌症发展的高风险。毒性最强的菌株具有编码4型分泌系统的cag致病岛（cagPAI），该系统允许将细菌效应物递送到胃上皮细胞中，诱导促炎反应和表型改变，使人联想到上皮向间充质转化（EMT）。本研究对H. pylori感染的胃上皮细胞，并研究它们与NF-κ B活化的关系。用cagPAI+ H攻击培养的人胃上皮细胞系。pylori菌株或CAG同基因突变体。观察其形态学变化、上皮和间质基因表达及EMT相关microRNA。H.幽门螺杆菌上调间充质标志物，包括ZEB 1。该转录因子主要参与感染细胞的间质转化，其上调依赖于cagPAI和NF-κ B活化。用免疫组化法检测cagPAI+ H组胃粘膜中ZEB 1的表达和NF-κ B的活化。幽门螺杆菌感染患者胃上皮细胞系表达高水平的miR-200，其与ZEB 1以相互负反馈环连接，并在非感染条件下维持其上皮表型。然而，尽管ZEB 1上调和间充质形态，但感染后miR-200 b/c仍增加。在miR-200 B-200 a-429簇启动子中，我们鉴定了功能性NF-κ B结合位点，其在感染后募集NF-κ B并反式激活microRNA簇转录。结论：在胃上皮细胞中，cagPAI+ H.幽门螺杆菌激活NF-κ B B，NF-κ B反式激活ZEB 1，随后促进间充质转化。miR-200水平的出乎意料的N-F κ B依赖性增加可能阻碍了在这种危急情况下上皮身份的不可逆丧失。
Chronic Helicobacter pylori infection provokes an inflammation of the gastric mucosa, at high risk for ulcer and cancer development. The most virulent strains harbor the cag pathogenicity island (cagPAI) encoding a type 4 secretion system, which allows delivery of bacterial effectors into gastric epithelial cells, inducing pro-inflammatory responses and phenotypic alterations reminiscent of an epithelial-to-mesenchymal transition (EMT). This study characterizes EMT features in H. pylori-infected gastric epithelial cells, and investigates their relationship with NF-kappa B activation. Cultured human gastric epithelial cell lines were challenged with a cagPAI+ H. pylori strain or cag isogenic mutants. Morphological changes, epithelial and mesenchymal gene expression and EMT-related microRNAs were studied. H. pylori up-regulates mesenchymal markers, including ZEB1. This transcription factor is prominently involved in the mesenchymal transition of infected cells and its up-regulation depends on cagPAI and NF-kappa B activation. ZEB1 expression and NF-kappa B activation were confirmed by immunohistochemistry in gastric mucosa from cagPAI+ H. pylori-infected patients. Gastric epithelial cell lines express high miR-200 levels, which are linked to ZEB1 in a reciprocal negative feedback loop and maintain their epithelial phenotype in non-infected conditions. However, miR-200b/c were increased upon infection, despite ZEB1 up-regulation and mesenchymal morphology. In the miR-200b-200a-429 cluster promoter, we identified a functional NF-kappa B binding site, recruiting NF-kappa B upon infection and trans-activating the microRNA cluster transcription. In conclusion, in gastric epithelial cells, cagPAI+ H. pylori activates NF-kappa B, which transactivates ZEB1, subsequently promoting mesenchymal transition. The unexpected N-F kappa B-dependent increase of miR-200 levels likely thwarts the irreversible loss of epithelial identity in that critical situation.