title: Magnesium sulfate inhibits the secretion of high mobility group box 1 from lipopolysaccharide-activated RAW264.7 macrophages in vitro.
abstract: BACKGROUND
  High mobility group box 1 (HMGB1) is an important inflammatory factor that is closely related to mortality in patients with sepsis. High magnesium therapy has been proved to reduce sepsis-related mortality and sepsis-induced pathologic complications. These effects result from reduced expression and release of many inflammatory cytokines, although it is not clear whether high magnesium affects the expression and release of HMGB1. In the present study, we explored the effect of magnesium sulfate on the expression and release of HMGB1 in lipopolysaccharide (LPS)-activated macrophages.
  
  
  METHODS
  RAW264.7 cells were incubated with LPS in the presence or absence of various concentrations of magnesium sulfate. An enzyme-linked immunosorbent assay was used to detect the levels of HMGB1 in the culture supernatant. Real-time polymerase chain reaction was used to assess the expression of HMGB1 mRNA. The nuclear/cytoplasm extraction kit was used to extract the nuclear and cytoplasmic proteins. Western blotting was used to observe the changes in the translocation of HMGB1 from the nucleus to the cytoplasm. The nuclear factor (NF)-κB p50/p65 Transcription Factor Assay Kit was used to analyze NF-κB activity in the nuclear extract.
  
  
  RESULTS
  We found that magnesium sulfate inhibited translocation of HMGB1 from the nucleus to the cytoplasm and its extracellular release in LPS-activated macrophages and also suppressed the expression of HMGB1 mRNA. Furthermore, magnesium sulfate inhibited the translocation of NF-κB from the cytoplasm to the nucleus in LPS-activated macrophages in a dose-dependent manner.
  
  
  CONCLUSIONS
  Our study has demonstrated that magnesium sulfate inhibits the translocation of HMGB1 from the nucleus to the cytoplasm and the expression of HMGB1 mRNA in a dose-dependent manner. The mechanism responsible for these effects involves the NF-κB signaling pathway.
authors.affiliation: Department of Anesthesiology, Shanghai First People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Liu
authors.forename: Junjie
authors.initials: J
authors.lastname: Zhang
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Huang
authors.forename: Lina
authors.initials: L
authors.lastname: Huang
authors.forename: Shitong
authors.initials: S
authors.lastname: Li
authors.forename: Zhengping
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D024243:HMGB1 Protein / Q000378:metabolism*; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects* / Q000502:physiology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008278:Magnesium Sulfate / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D024243:HMGB1 Protein; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D008278:Magnesium Sulfate