Increased Expression of Toll-Like Receptor-4 in Helicobacter pylori Infected Gastric Mucosa

Park, Joon Yong; Han, Dong Soo; Kim, Bo Hyun; Kang, Eun Kyung; Li, Yingchun; Lee, Hang Lak; Kim, Jin Bae; Sohn, Joo Hyun; Choi, Ho Soon; Kang, Jung Ock; Hahm, Joon Soo

Abstract

BACKGROUND/AIMS: Toll-like receptors (TLRs) represent a pattern recognition receptors with an ability of specific recognition of pathogens. TLRs appear to respond to pathogens and induce NF- B activation. TLR2 and 4 seem to be related to the initiation of immune response against gram negative and positive bacteria. We investigated the effect of Helicobacter pylori (H. pylori) infection on the expression of TLRs on the gastric mucosa. METHODS: For 35 endoscopic gastric mucosa samples, histologic grading of H. pylori infection and inflammatory cell infiltration were performed. The mRNA expression of TLR2, 3, and 4 was examined by RT-PCR. Immunohistochemistry demonstrated the distribution of TLR2 and 4 in gastric mucosal biopsies. RESULTS: H. pylori positive gastric mucosa expressed higher TLR4/GAPDH ratio than H. pylori negative gastric mucosa (p=0.035), while no significant difference in the expression of TLR2 and 3 was detected (p=0.129, p=0.176). The severity of neutrophil infiltration showed a significant positive correlation with TLR4/GAPDH ratio (p=0.045, r=0.342). Immunohistochemistry using anti-TLR4 and anti-TLR2 antibody revealed the expression of TLR4 in the epithelial cells of H. pylori-infected gastric mucosa. CONCLUSIONS: H. pylori infection induces TLR4 expression in the human gastric epithelium, which suggests a certain role of TLR4 in the mucosal inflammatory reaction to H. pylori infection.