Suppressed Gastric Mucosal TGF-?1 Increases Susceptibility to H. pylori-Induced Gastric Inflammation and Ulceration: A Stupid Host Defense Response

摘要

Background/Aims: Loss of transforming growth factor Ղ1 (TGF-Ղ1) exhibits a similar pathology to that seen in a subset of individuals infected with Helicobacter pylori, including propagated gastric inflammation, oxidative stress, and autoimmune features. We thus hypothesized that gastric mucosal TGF-Ղ1 levels could be used to determine the outcome after H. pylori infection. Methods: Northern blot for the TGF-Ղ1 transcript, staining of TGF-Ղ1 expression, luciferase reporter assay, and enzyme-linked immunosorbent assay for TGF-Ղ1 levels were performed at different times after H. pylori infection. Results: The TGF-Ղ1 level was markedly lower in patients with H. pylori-induced gastritis than in patients with a similar degree of gastritis induced by nonsteroidal anti-inflammatory drugs. There was a significant negative correlation between the severity of inflammation and gastric mucosal TGF-Ղ1 levels. SNU-16 cells showing intact TGF-Ղ signaling exhibited a marked decrease in TGF-Ղ1 expression, whereas SNU-638 cells defective in TGF-Ղ signaling exhibited no such decrease after H. pylori infection. The decreased expressions of TGF-Ղ1 in SNU-16 cells recovered to normal after 24 hr of H. pylori infection, but lasted very spatial times, suggesting that attenuated expression of TGF-Ղ1 is a host defense mechanism to avoid attachment of H. pylori. Conclusions: H. pylori infection was associated with depressed gastric mucosal TGF-Ղ1 for up to 24 hr, but this apparent strategy for rescuing cells from H. pylori attachment exacerbated the gastric inflammation. (Gut Liver 2010;4:43-53)