Early release of HMGB-1 from neurons after the onset of brain ischemia.
The nuclear protein high-mobility group box 1 (HMGB-1) promotes inflammation in sepsis, but little is known about its role in brain ischemia-induced inflammation. We report that HMGB-1 and its receptors, receptor for advanced glycation end products (RAGE), Toll-like receptor 2 (TLR2), and TLR4, were expressed in normal brain and in cultured neurons, endothelia, and glial cells. During middle cerebral artery occlusion (MCAO), in mice, HMGB-1 immunostaining rapidly disappeared from all cells within the striatal ischemic core from 1 h after onset of occlusion. High-mobility group box 1 translocation from nucleus to cytoplasm was observed within the cortical periinfarct regions 2 h after ischemic reperfusion (2 h MCAO). High-mobility group box 1 predominantly translocated to the cytoplasm or disappeared in cells that colabeled with the neuronal marker NeuN. Furthermore, RAGE was robustly expressed in the periinfarct region after MCAO. Cellular release of HMGB-1 was detected by immunoblotting of cerebrospinal fluid as early as 2 h after ischemic reperfusion (2 h MCAO). High-mobility group box 1 released from neurons, in vitro, after glutamate excitotoxicity, maintained biologic activity and induced glial expression of tumor necrosis factor alpha (TNFalpha). Anti-HMGB-1 antibody suppressed TNFalpha upregulation in astrocytes exposed to conditioned media from glutamate-treated neurons. Moreover, TNFalpha and the cytokine intercellular adhesion molecule-1 increased in cultured glia and endothelial cells, respectively, after adding recombinant HMGB-1. In conclusion, HMGB-1 is released early after ischemic injury from neurons and may contribute to the initial stages of the inflammatory response.
Qiu
Jianhua
J
Stroke and Neurovascular Regulation Laboratory, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA. jqui@partners.org
Nishimura
Masaki
M
Wang
Yumei
Y
Sims
John R
JR
Qiu
Sumei
S
Savitz
Sean I
SI
Salomone
Salvatore
S
Moskowitz
Michael A
MA
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001253:Astrocytes / Q000276:immunology / Q000378:metabolism; D002545:Brain Ischemia / Q000276:immunology* / Q000378:metabolism*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004660:Encephalitis / Q000276:immunology* / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D005110:Extracellular Space / Q000276:immunology / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D024243:HMGB1 Protein / Q000276:immunology / Q000378:metabolism*; D020244:Infarction, Middle Cerebral Artery / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000906:Antibodies; D017077:Culture Media, Conditioned; D024243:HMGB1 Protein; D012333:RNA, Messenger; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D018698:Glutamic Acid