Mechanism of HMGB-1-induced inflammatory response in human bronchial epithelial cells

Haibei Dong ,Xiaojin Wu ,Wei Wang ,Lei Shi ,Xiaoqian Liu ,Yuanyuan Chen

doi:10.3760/cma.j.issn.1674-1927.2018.01.002

Abstract

Objective To investigate the mechanism of extracellular high mobility group box 1 (HMGB-1) -induced inflammatory response in normal human bronchial epithelial cells (NHBE) . Methods The subjects were divided into the control group, HMGB-1 group, HMGB-1+RAGE antibody (RAGE-Ab) group, HMGB-1+JNK inhibitor SP600125 group, and RAGE-Ab group. Immunofluorescence technique was used to analyze the expression of RAGE protein. ELISA assay was used to determine the levels of inflammatory cytokines TNF-α, IL-8, IL-10 and MCP-1 in NHBE cell supernatant. Western blotting was used to analyze the expression of RAGE, p-JNK and p-NF-κB p65 protein. Results HMGB-1 could dose-dependently induce RAGE protein expression. HMGB-1 could significantly increase the intensity of fluorescence at the concentrations of 5 and 10 μg/ml compared with that in the control group (P<0.05) . The RAGE expression decreased significantly in the HMGB-1+RAGE-Ab group (P<0.05) , whereas there was no significant change in RAGE protein expression in the HMGB-1+SP600125 group. Compared with the blank control group, the levels of TNF-α, IL-8, IL-10, and MCP-1 significantly increased after the treatment with HMGB-1 (P<0.05) . The release of inflammatory factors significantly decreased in the HMGB-1+RAGE-Ab group and HMGB-1+SP600125 group (P<0.05) . Compared with the blank control group, the protein expression of RAGE, p-JNK and p-NF-κB p65 dose-dependently increased after the treatment of NHBE cells with HMGB-1 (P<0.05) . The protein expression of RAGE, p-JNK and p-NF-κB p65 in the HMGB-1+RAGE-Ab group significantly decreased (P<0.05) . The protein expression of p-JNK and p-NF-κB p65 in the HMGB-1+SP600125 group significantly decreased (P<0.05) , whereas there was no significant change in the expression of RAGE. Conclusion The inflammatory response induced by HMGB-1 in the NHBE cells is mediated through the RAGE/JNK/NF-κB signaling pathway. Key words: HMGB-1; NHBE; Inflammation; RAGE; JNK; NF-κB

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