Role of MD-2 in Tool-like receptor 4-dependent signaling in Helicobacter-pylori-associated gastritis

MD-2 在幽门螺杆菌相关胃炎工具样受体 4 依赖性信号传导中的作用

基本信息

批准号：
13670520
负责人：
ISHIHARA Shunji
金额：
$ 2.24万
依托单位：
Shimane Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670520/
关键词：
TLR4 MD-2 H.pyvlori ECL cell Toll-like receptor H.Pylori

项目摘要

Helicobacter pylori (H. pylori) lipopolysccharide (LPS) is one of the major virulence factors in the induction of gastritis. LPS-dependent activation of gastric epithelial cells and infiltrating macrophages leads to secretion of several proinflammatory cytokines. However, little is known about the recognition system of H. pylori LPS in gastric mucosal cells. Recent studies have shown that LPS initiates signal transduction through toll-like receptor (TLR)-4, and this pathway is activated by MD-2. The aim of this study is to investigate TRL-4/MD-2 complex-specific recognition of H. pylori LPS in gastric mucosal cells. Gastric antral biopsy samples were taken from patients with and without H. pylori infection. Four gastric cancer cell lines (MKN-7, MKN-28, MKN-45 and AGS) were used for in vitro study. Expression of TLR-4 and MD-2 in gastric biopsy specimens and gastric cancer cell lines was examined by reverse-transcription polymerase chain reaction and western blot analysis. Localization of TLR-4 in histological sections was also evaluated by immunohistochemistry. Luciferase assay was performed for the assessment of H. pylori LPS-induced NF-kB activation in gastric epithelial cells and transient transfectants expressing TLR-4 and/or MD-2. TLR-4 was constitutively expressed in the stomach with and without H. pylori infection and localized in gastric epithelial cells and infiltrating mononuclear cells. However, the expression of MD-2 in H. pylori-positive subjects was higher than that in H. pylori-negative subjects. In vitro, all gastric epithelial cells expressed both TLR-4 and MD-2 and H. pylori LPS stimulated NF-kB activation in these cells. LPS responses in transfectant expressing both TLR-4 and MD-2 was significantly higher than that expressing only TLR-4. TLR-4/MD-2 complex is essential for the recognition of H. pylori LPS and MD-2 may regulate TLR-4-dependent signaling in the development of H. pylori-associated gastritis.

幽门螺杆菌（幽门螺杆菌）脂多糖（LPS）是胃炎诱导的主要毒力因素之一。 LPS依赖性胃上皮细胞和浸润巨噬细胞的激活导致几种促炎细胞因子的分泌。然而，对于胃粘膜细胞中幽门螺杆菌LPS的识别系统知之甚少。最近的研究表明，LPS通过Toll样受体（TLR）-4启动信号转导，该途径被MD-2激活。这项研究的目的是研究胃粘膜细胞中幽门螺杆菌LPS的TRL-4/MD-2复合物特异性识别。从患有和没有幽门螺杆菌感染的患者中采集胃肛门活检样品。在体外研究中使用了四种胃癌细胞系（MKN-7，MKN-28，MKN-45和AGS）。 TLR-4和MD-2在胃活检标本和胃癌细胞系中的表达通过反向转录聚合酶链反应和蛋白质印迹分析检查。还通过免疫组织化学评估了组织学切片中TLR-4的定位。进行荧光素酶测定，以评估胃上皮细胞中幽门螺杆菌LPS诱导的NF-KB激活，以及表达TLR-4和/或MD-2的瞬时转染剂。 TLR-4在胃中有或没有幽门螺杆菌感染的胃中表达，并局部在胃上皮细胞和浸润的单核细胞中。然而，幽门螺杆菌阳性受试者中MD-2的表达高于幽门螺杆菌阴性受试者。在体外，所有胃皮细胞均表达TLR-4和MD-2和幽门螺杆菌LPS均刺激了这些细胞中的NF-KB激活。表达TLR-4和MD-2的转染剂中的LPS反应显着高于仅表达TLR-4的LPS。 TLR-4/MD-2复合物对于幽门螺杆菌LPS的识别至关重要，MD-2可能调节TLR-4依赖性信号传导在幽门螺杆菌相关的胃炎的发展中。