title: High mobility group box 1/Toll-like receptor danger signaling increases brain neuroimmune activation in alcohol dependence.
abstract: BACKGROUND
  Innate immune gene expression is regulated in part through high mobility group box 1 (HMGB1), an endogenous proinflammatory cytokine, that activates multiple members of the interleukin-1/Toll-like receptor (TLR) family associated with danger signaling. We investigated expression of HMGB1, TLR2, TLR3, and TLR4 in chronic ethanol-treated mouse brain, postmortem human alcoholic brain, and rat brain slice culture to test the hypothesis that neuroimmune activation in alcoholic brain involves ethanol activation of HMGB1/TLR danger signaling.
  
  
  METHODS
  Protein levels were assessed using Western blot, enzyme-linked immunosorbent assay, and immunohistochemical immunoreactivity (+IR), and messenger RNA (mRNA) levels were measured by real time polymerase chain reaction in ethanol-treated mice (5 g/kg/day, intragastric, 10 days + 24 hours), rat brain slice culture, and postmortem human alcoholic brain.
  
  
  RESULTS
  Ethanol treatment of mice increased brain mRNA and +IR protein expression of HMGB1, TLR2, TLR3, and TLR4. Postmortem human alcoholic brain also showed increased HMGB1, TLR2, TLR3, and TLR4 +IR cells that correlated with lifetime alcohol consumption, as well as each other. Ethanol treatment of brain slice culture released HMGB1 into the media and induced the proinflammatory cytokine, interleukin-1 beta (IL-1β). Neutralizing antibodies to HMGB1 and small inhibitory mRNA to HMGB1 or TLR4 blunted ethanol induction of IL-1β.
  
  
  CONCLUSIONS
  Ethanol-induced HMGB1/TLR signaling contributes to induction of the proinflammatory cytokine, IL-1β. Increased expression of HMGB1, TLR2, TLR3, and TLR4 in alcoholic brain and in mice treated with ethanol suggests that chronic alcohol-induced brain neuroimmune activation occurs through HMGB1/TLR signaling.
authors.affiliation: Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA. ftcrews@med.unc.edu
authors.forename: Fulton T
authors.initials: FT
authors.lastname: Crews
authors.forename: Liya
authors.initials: L
authors.lastname: Qin
authors.forename: Donna
authors.initials: D
authors.lastname: Sheedy
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Vetreno
authors.forename: Jian
authors.initials: J
authors.lastname: Zou
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D016022:Case-Control Studies; D000431:Ethanol / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D008875:Middle Aged; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051196:Toll-Like Receptor 3 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D024243:HMGB1 Protein; D053583:Interleukin-1beta; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D000431:Ethanol