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Helicobacter pylori Activates HMGB1 Expression and Recruits RAGE into Lipid Rafts to Promote Inflammation in Gastric Epithelial Cells

View Article: PubMed Central - PubMed

ABSTRACT

Helicobacter pylori infection is associated with several gastrointestinal disorders in the human population worldwide. High-mobility group box 1 (HMGB1), a ubiquitous nuclear protein, mediates various inflammation functions. The interaction between HMGB1 and receptor for advanced glycation end-products (RAGE) triggers nuclear factor (NF)-κB expression, which in turn stimulates the release of proinflammatory cytokines, such as interleukin (IL)-8, and enhances the inflammatory response. However, how H. pylori activates HMGB1 expression and mobilizes RAGE into cholesterol-rich microdomains in gastric epithelial cells to promote inflammation has not been explored. In this study, we found that HMGB1 and RAGE expression increased significantly in H. pylori-infected cells compared with -uninfected cells. Blocking HMGB1 by neutralizing antibody abrogated H. pylori-elicited RAGE, suggesting that RAGE expression follows HMGB1 production, and silenced RAGE-attenuated H. pylori-mediated NF-κB activation and IL-8 production. Furthermore, significantly more RAGE was present in detergent-resistant membranes extracted from H. pylori-infected cells than in those from -uninfected cells, indicating that H. pylori exploited cholesterol to induce the HMGB1 signaling pathway. These results indicate that HMGB1 plays a crucial role in H. pylori-induced inflammation in gastric epithelial cells, which may be valuable in developing treatments for H. pylori-associated diseases.

No MeSH data available.


H. pylori induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori for 6 h with various MOIs (A–C), including an MOI of 100 at different time points (D–F). Total cell lysates were prepared to evaluate HMGB1 and RAGE expression by Western blot analysis. Protein expression levels were quantified by densitometric analysis and normalized to β-actin (B,C,E,F). Statistical significance was evaluated by Student’s t-test (*P < 0.05).
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Figure 1: H. pylori induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori for 6 h with various MOIs (A–C), including an MOI of 100 at different time points (D–F). Total cell lysates were prepared to evaluate HMGB1 and RAGE expression by Western blot analysis. Protein expression levels were quantified by densitometric analysis and normalized to β-actin (B,C,E,F). Statistical significance was evaluated by Student’s t-test (*P < 0.05).

Mentions: We first investigated whether H. pylori infection induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori at various MOIs (0–500) for 6 h, and the expression levels of HMGB1 and RAGE were determined by Western blot assay. As shown in Figures 1A–C, HMGB1 and RAGE expression levels were markedly increased in cells infected with H. pylori at an MOI of 100, whereas they were decreased at higher MOIs of 200 and 500. In addition, AGS cells were infected with H. pylori (MOI = 100) for different durations (0–24 h) in parallel. H. pylori-induced HMGB1 and RAGE expression peaked with 6 h of infection and decreased after incubation for 16–24 h (Figures 1D–F). These results suggest that H. pylori induces HMGB1 and RAGE expression in AGS cells, and that the optimal conditions for infection are an MOI of 100 and incubation for 6 h.


Helicobacter pylori Activates HMGB1 Expression and Recruits RAGE into Lipid Rafts to Promote Inflammation in Gastric Epithelial Cells
H. pylori induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori for 6 h with various MOIs (A–C), including an MOI of 100 at different time points (D–F). Total cell lysates were prepared to evaluate HMGB1 and RAGE expression by Western blot analysis. Protein expression levels were quantified by densitometric analysis and normalized to β-actin (B,C,E,F). Statistical significance was evaluated by Student’s t-test (*P < 0.05).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC5016528&req=5

Figure 1: H. pylori induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori for 6 h with various MOIs (A–C), including an MOI of 100 at different time points (D–F). Total cell lysates were prepared to evaluate HMGB1 and RAGE expression by Western blot analysis. Protein expression levels were quantified by densitometric analysis and normalized to β-actin (B,C,E,F). Statistical significance was evaluated by Student’s t-test (*P < 0.05).
Mentions: We first investigated whether H. pylori infection induces HMGB1 and RAGE expression in gastric epithelial cells. AGS cells were infected with H. pylori at various MOIs (0–500) for 6 h, and the expression levels of HMGB1 and RAGE were determined by Western blot assay. As shown in Figures 1A–C, HMGB1 and RAGE expression levels were markedly increased in cells infected with H. pylori at an MOI of 100, whereas they were decreased at higher MOIs of 200 and 500. In addition, AGS cells were infected with H. pylori (MOI = 100) for different durations (0–24 h) in parallel. H. pylori-induced HMGB1 and RAGE expression peaked with 6 h of infection and decreased after incubation for 16–24 h (Figures 1D–F). These results suggest that H. pylori induces HMGB1 and RAGE expression in AGS cells, and that the optimal conditions for infection are an MOI of 100 and incubation for 6 h.

View Article: PubMed Central - PubMed

ABSTRACT

Helicobacter pylori infection is associated with several gastrointestinal disorders in the human population worldwide. High-mobility group box 1 (HMGB1), a ubiquitous nuclear protein, mediates various inflammation functions. The interaction between HMGB1 and receptor for advanced glycation end-products (RAGE) triggers nuclear factor (NF)-&kappa;B expression, which in turn stimulates the release of proinflammatory cytokines, such as interleukin (IL)-8, and enhances the inflammatory response. However, how H. pylori activates HMGB1 expression and mobilizes RAGE into cholesterol-rich microdomains in gastric epithelial cells to promote inflammation has not been explored. In this study, we found that HMGB1 and RAGE expression increased significantly in H. pylori-infected cells compared with -uninfected cells. Blocking HMGB1 by neutralizing antibody abrogated H. pylori-elicited RAGE, suggesting that RAGE expression follows HMGB1 production, and silenced RAGE-attenuated H. pylori-mediated NF-&kappa;B activation and IL-8 production. Furthermore, significantly more RAGE was present in detergent-resistant membranes extracted from H. pylori-infected cells than in those from -uninfected cells, indicating that H. pylori exploited cholesterol to induce the HMGB1 signaling pathway. These results indicate that HMGB1 plays a crucial role in H. pylori-induced inflammation in gastric epithelial cells, which may be valuable in developing treatments for H. pylori-associated diseases.

No MeSH data available.