In vivo heat shock protein assembles with septic liver NF-kappaB/I-kappaB complex regulating NF-kappaB activity.
This study elucidates the mechanism through which heat shock treatment influences the outcome of sepsis. Post-heat shock sepsis was induced in rats by CLP 24 h after whole-body hyperthermia. Liver cytosolic and nuclear fractions were collected and analyzed in early and late sepsis rats (sacrificed 9 and 18 h after CLP, respectively). During sepsis, levels of I-kappaB and nuclear factor-kappaB (NF-kappaB) declined in the cytosol of liver, whereas NF-kappaB increased in nucleus. NF-kappaB activity was significantly enhanced during sepsis, and the products of NF-kappaB target genes, such as TNF-alpha and inducible nitric oxide synthase (iNOS), were overexpressed. Heat shock treatment, inducing heat shock protein synthesis, prevented down-regulation of cytosolic I-kappaB and decreased translocation of NF-kappaB into the nucleus. Therefore, the sepsis-induced acceleration of NF-kappaB activation was inhibited. Expression of TNF-alpha and iNOS mRNA was also down-regulated. Coimmunoprecipitation with anti-NF-kappaB (p65) and anti-IkappaB antibodies verified an assembling phenomenon of heat shock protein (HSP) 72 with NF-kappaB and I-kappaB. We suggest that the mechanism preventing septic activation of NF-kappaB is that oversynthesized HSP72 forms a complex with NF-kappaB/I-kappaB, thus inhibiting nuclear translocation of NF-kappaB. HSP72 appears to play a crucial protective role in modulating the gene expression controlled by NF-kappaB in sepsis.
Chen
Hsiang-Wen
HW
Department of Microbiology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan.
Kuo
Hung-Tien
HT
Wang
Shu-Jung
SJ
Lu
Tzong-Shi
TS
Yang
Rei-Cheng
RC
D021581:Active Transport, Cell Nucleus; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000737:chemistry; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D006979:Hyperthermia, Induced; D020672:I-kappa B Proteins / Q000378:metabolism*; D047468:Immunoprecipitation; D008099:Liver / Q000378:metabolism / Q000473:pathology*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018805:Sepsis / Q000473:pathology*; D013997:Time Factors; D016896:Treatment Outcome
D020672:I-kappa B Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D004247:DNA