title: Regulation of inflammatory transcription factors by heat shock protein 70 in primary cultured astrocytes exposed to oxygen-glucose deprivation.
abstract: Inflammation is an important event in ischemic injury. These immune responses begin with the expression of pro-inflammatory genes modulating transcription factors, such as nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and signal transducers and activator of transcription-1 (STAT-1). The 70-kDa heat shock protein (Hsp70) can both induce and arrest inflammatory reactions and lead to improved neurological outcome in experimental brain injury and ischemia. Since Hsp70 are induced under heat stress, we investigated the link between Hsp70 neuroprotection and phosphorylation of inhibitor of κB (IκB), c-Jun N-terminal kinases (JNK) and p38 through co-immunoprecipitation and enzyme-linked immunosorbent assay (ELISA) assay. Transcription factors and pro-inflammatory genes were quantified by immunoblotting, electrophoretic-mobility shift assay and reverse transcription-polymerase chain reaction assays. The results showed that heat stress led to Hsp70 overexpression which rendered neuroprotection after ischemia-like injury. Overexpression Hsp70 also interrupts the phosphorylation of IκB, JNK and p38 and blunts DNA binding of their transcription factors (NF-κB, AP-1 and STAT-1), effectively downregulating the expression of pro-inflammatory genes in heat-pretreated astrocytes. Taken together, these results suggest that overexpression of Hsp70 may protect against brain ischemia via an anti-inflammatory mechanism by interrupting the phosphorylation of upstream of transcription factors.
authors.affiliation: Department of Neurology, University of California, San Francisco and Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Neurology, University of California, San Francisco and Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Yenari
authors.affiliation: Department of Anatomy, BK21 Plus Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul 120-752, South Korea. Electronic address: jelee@yuhs.ac.
authors.forename: J E
authors.initials: JE
authors.lastname: Lee
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D004660:Encephalitis / Q000378:metabolism*; D005947:Glucose; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response; D020672:I-kappa B Proteins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008813:Mice, Inbred ICR; D016328:NF-kappa B / Q000378:metabolism*; D010100:Oxygen; D010766:Phosphorylation; D061251:Primary Cell Culture; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; D050794:STAT1 Transcription Factor; D018808:Transcription Factor AP-1; D048031:JNK Mitogen-Activated Protein Kinases; D005947:Glucose; D010100:Oxygen
keywords: 70-kDa heat shock protein; inflammation; ischemic injury; phosphorylation; transcription factors