Hypoxia-induced HMGB1Release In Macrophages And Its Mechanisms

Objective To investigate the extracellular release of high mobility group box1(HMGB1) in macrophages induced by hypoxia and its possible mechanisms.Methods The changes of HMGB1mRNA expression, HMGB1concentration in the culture medium and the intracellular distribution of HMGB1were assayed after RAW264.7macrophages were subjected to hypoxia (1%O2or100μmol/L CoCl2) with intended times. Inhibitory effects of N-acetylcysteine (NAC) and MAPK pathway inhibitors(PD98059, SP600125, SB202190) with various concenrtrations, were observed on extracellular HMGB1release in hypoxia-induced macrophages. The HMGB1concentration and the level of HMGB1mRNA expression were determined by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-PCR),respectively.Results The level of HMGB1mRNA expression and the HMGB1concentration in the culture medium increased after RAW264.7macrophages were subjected to hypoxia culture for12h (P<0.05or P<0.01). The nuclear HMGB1translocated to the cytoplasm after hypoxia culture for12h. NAC with10mmol/L or100mmol/L, PD98059and SP600125with5μ mol/L or20μ mol/L partly inhibited extracellular release of HMGB1in hypoxia-cultured RAW264.7macrophages in a dose-dependent manner.Conclusions Hypoxia induces macrophages to release HMGB1, which may be involved with intracellular production of reactive oxygen species. Intracellular MEK and JNK signaling pathway is involved in hypoxia-induced release of HMGB1.