Physiological action of nitric oxide produced by a stimulation of endotoxin from Helicobacter pylori on gastric mucosa

幽门螺杆菌内毒素刺激产生一氧化氮对胃粘膜的生理作用

基本信息

批准号：
15590087
负责人：
YOSHIMURA Tetsuhiko
金额：
$ 2.3万
依托单位：
Yamagata Promotional Organization for Industrial Technology (2004)Yamagata Public Corporation For the Development Of Industry, Institute Life Support Technology (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Helicobacter pylori, a gram-negative bacterium, is the primary cause of gastritis and a major contributor to peptic ulcer disease. Despite its importance as a human pathogen, principal factor of pathogenicity of the bacterium remains to be identified Nitric oxide (NO) released due to the induction of Ca^<2+> independent isoform of nitric oxide synthase (iNOS) by lipopolysaocharide or endotoxin from a gram-negative bacterium bas been known to be deleterious to a gastric mucosa. In the present shady, to elucidate the physiological action of H.pylori LPS on gastric mucosa and the role of NO, we were carried out both in vivo and in vitro study by employing E.coli LPS as a control.1. IT pylori LPS was isolated from gram-order bacteria by the phenol-water extraction method, and then further purified by tine enzymatic digestion of RNA, DNA, and proteins.2. In vitro cross talk between products from iNOS and cyclooxygenase (COX) in the rat gastric mucosa during endotoxemia was examined in vivo. The results demonstrate that in the E cob LPS-treated rat gastric mucosa, PGE2, a COX product, enhances after activation of iNOS. The effect of COX activity on iNOS-NO pathway is important in the regulation of gastric mucosal integrity inflammatory states.3. We further elucidated the interaction of LPS with gastric epithelial cells by using a normal mouse gastric surface mucous cell line (GSM06). Our findings suggest that both LPSs from H.pylori and E.coli induce the iNOS and Toll-like receptor (TLR) 2 through the TLR 4 expressed constitutively in GSM06. This mechanism on TLR 2 induction can be crucial for maintenance of gastric mucosal integrity.

幽门螺杆菌是一种革兰氏阴性细菌，是胃炎的主要原因，也是消化性溃疡病的主要原因。尽管其作为人类病原体很重要，但该细菌致病性的主要因素仍有待确定。由于脂多糖或内毒素诱导一氧化氮合酶 (iNOS) 的 Ca^2+ 独立亚型而释放一氧化氮 (NO)。已知革兰氏阴性细菌对胃粘膜有害。目前，为了阐明H.pylori LPS对胃黏膜的生理作用以及NO的作用，我们以大肠杆菌LPS为对照，进行了体内外研究。 1．采用苯酚-水提取法从革兰氏菌中分离得到IT pylori LPS，并通过酶切RNA、DNA和蛋白质进一步纯化。 2．体内检查了内毒素血症期间大鼠胃粘膜中 iNOS 和环氧合酶 (COX) 产物之间的体外串扰。结果表明，在 E cob LPS 处理的大鼠胃粘膜中，COX 产物 PGE2 在 iNOS 激活后增强。 COX活性对iNOS-NO通路的影响对于调节胃黏膜完整性炎症状态具有重要意义。3．我们通过使用正常小鼠胃表面粘液细胞系（GSM06）进一步阐明了LPS与胃上皮细胞的相互作用。我们的研究结果表明，来自幽门螺杆菌和大肠杆菌的 LPS 通过在 GSM06 中组成型表达的 TLR 4 诱导 iNOS 和 Toll 样受体 (TLR) 2。 TLR 2 诱导的这种机制对于维持胃粘膜完整性至关重要。