Abstract: Objective To explore the signaling molecules relate HMGB1 expression in murine macrophage-like cell line RAW264.7 cells induced by lipopolysaccharide, HMGB1, p38MAPK, NF-κB and CBP were detected. Methods After stimulated by LPS, p38MAPK, NF-κB and CBP protein in cytoplasm and nucelus were observed by immunocytochemistry and laser confocal scanning microscopy. HMGB1 protein in supernatant was measured by ELISA, the expression of HMGB1 mRNA in cultured cells was determined by Real-time PCR. Cultured cells cytoplasm and nucleus HMGB1 protein were detected by Western blot. Results With LPS stimulation, the green fluorescence of p38MAPK was gradually increased and the green fluorescence of NF-κB was gradually weakened in cytoplasm, while in nucleus, the green fluorescence of both NF-κB and CBP was gradually increased, and reached the peak after 6 h. HMGB1 protein in supernatant and cytoplasm increased gradually from 12 to 48 h after stimulated by LPS. HMGB1 protein in nucleus decreased gradually from 12 to 24 h after LPS stimulated, increased gradually after 36 h(P<0.01). The expression of HMGB1 mRNA has no significantly changed from 0 to 12 h but enhanced significantly from 24 to 48 h after LPS stimulated (P<0.01). Conclusions LPS activated p38MAPK、NF-κB and CBP signaling pathway, which led to HMGB1 deacetylated and transferred into cytoplasm, finally released into excellular.

Key words: lipopolysaccharide, high mobility group box-1 protein, mechanisms