幽门螺杆菌通过刺激巨噬细胞分泌 CCL3 破坏胃黏膜稳态。
Helicobacter pylori disrupts gastric mucosal homeostasis by stimulating macrophages to secrete CCL3.
机构信息
Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
National Clinical Research Center for Digestive Disease, Beijing Digestive Disease Center, State Key Laboratory of Digestive Health, Beijing, 100050, China.
出版信息
Cell Commun Signal. 2024 May 10;22(1):263. doi: 10.1186/s12964-024-01627-5.
BACKGROUND
Helicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis.
METHODS
The expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry.
RESULTS
After H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased.
CONCLUSIONS
In summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.
背景
幽门螺杆菌（H. pylori）是胃炎的主要病因，通过多种致病机制破坏胃黏膜屏障的完整性。H. pylori 侵入胃黏膜后，与固有层中的免疫细胞相互作用。巨噬细胞是炎症反应的核心参与者，H. pylori 刺激它们分泌多种炎症因子，导致胃黏膜的慢性损伤。因此，本研究旨在探讨巨噬细胞分泌的炎症因子引起胃黏膜损伤的机制，这可能为 H. pylori 相关胃炎的发生提供新的机制。
方法
通过 RT-qPCR、Western blot 和 ELISA 检测 H. pylori 感染的巨噬细胞中 CCL3 的表达和分泌。通过 Western blot、免疫荧光和跨上皮电阻分析 H. pylori 感染的巨噬细胞培养物和 CCL3 对胃上皮细胞紧密连接的影响。EdU 和凋亡流式细胞术检测细胞增殖和凋亡水平。双荧光素酶报告基因检测和染色质免疫沉淀检测用于研究 CCL3 转录因子。最后，通过苏木精和伊红染色和免疫组织化学分析胃黏膜组织炎症和 CCL3 表达。
结果
H. pylori 感染后，巨噬细胞中表达和分泌的 CCL3 增加。H. pylori 感染的巨噬细胞培养物和 CCL3 破坏胃上皮细胞的紧密连接，而 CCL3 中和抗体和 CCL3 受体抑制剂改善了细胞间紧密连接的破坏。此外，H. pylori 感染的巨噬细胞培养物和 CCL3 重组蛋白刺激 P38 磷酸化，而 P38 磷酸化抑制剂改善了细胞间紧密连接的破坏。此外，鉴定出 STAT1 是 CCL3 的转录因子，H. pylori 通过 JAK1-STAT1 途径刺激巨噬细胞分泌 CCL3。最后，在小鼠注射鼠源 CCL3 重组蛋白后，胃黏膜损伤和炎症加重，P38 的磷酸化水平升高。
结论
综上所述，我们的研究结果表明，H. pylori 感染通过 JAK1-STAT1 途径刺激巨噬细胞分泌 CCL3。随后，CCL3 通过 P38 的磷酸化破坏胃上皮细胞的紧密连接。这可能是 H. pylori 相关胃炎胃黏膜损伤的新机制。
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