title: Heat shock response inhibits release of high mobility group box 1 protein induced by endotoxin in murine macrophages.
abstract: The purpose of this study was to evaluate the kinetic changes and the localization of high-mobility group box 1 protein (HMGB1) and to observe the effect of heat shock response (HSR) on the expression and release of HMGB1 in lipopolysaccharide (LPS)-activated murine macrophage-like RAW 264.7 cells. Reverse transcriptase (RT)-PCR and Western blot were used to examine HMGB1 expression after LPS treatment. The intracellular localization of HMGB1 in normal or LPS-activated cells was investigated by immunocytochemical analysis and HMGB1 released from cultured macrophages by Western blot. HSR was performed by incubating RAW 264.7 cells at 42.5 degrees C for 1 h then recovery at 37 degrees C for 12 h. The effect of HSR on expression and release of HMGB1 was observed. The results showed that a decrease of HMGB1 mRNA expression was observed at 18 h after LPS (500 ng/mL) treatment, although the total intracellular HMGB1 protein levels were not affected. A visible translocation of HMGB1 from the nuclear to the cytoplasm was observed at 20 h after stimulation with LPS (500 ng/mL). Furthermore, HMGB1 was released into the medium by LPS-activated RAW 264.7 cells in a time- and dose-dependent manner. Heat shock pretreatment significantly inhibited LPS-induced release of HMGB1 and the translocation of HMGB1 from the nucleus to the cytoplasm in RAW 264.7 cells. These findings suggest that the release of HMGB1 by LPS-activated macrophages is a late event in the pathogenesis of sepsis and that HSR could inhibit the release and translocation of HMGB1 induced by LPS.
authors.affiliation: Laboratory of Shock, Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, Hunan 410008, People's Republic of China.
authors.forename: Daolin
authors.initials: D
authors.lastname: Tang
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Shi
authors.forename: Lei
authors.initials: L
authors.lastname: Jang
authors.forename: Kangkai
authors.initials: K
authors.lastname: Wang
authors.forename: Weimin
authors.initials: W
authors.lastname: Xiao
authors.forename: Xianzhong
authors.initials: X
authors.lastname: Xiao
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D003470:Culture Media / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019446:Endotoxemia / Q000378:metabolism; D004731:Endotoxins / Q000378:metabolism*; D024243:HMGB1 Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018869:Heat-Shock Response; D006358:Hot Temperature; D007150:Immunohistochemistry; D007700:Kinetics; D008070:Lipopolysaccharides / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D013997:Time Factors
chemical_list: D003470:Culture Media; D004731:Endotoxins; D024243:HMGB1 Protein; D008070:Lipopolysaccharides; D012333:RNA, Messenger