期刊
HEPATOLOGY
卷 55, 期 5, 页码 1585-1595出版社
WILEY-BLACKWELL
DOI: 10.1002/hep.24802
关键词
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资金
- NIAAA NIH HHS [R01 AA017986-01A1, AA017986, R01 AA017986] Funding Source: Medline
- NIAID NIH HHS [P30 AI042845] Funding Source: Medline
Endotoxin-mediated proinflammatory cytokines play a significant role in the pathogenesis of acute and chronic liver diseases. Heat shock protein 90 (molecular weight, 90 kDa) (hsp90) functions as an important chaperone of lipopolysaccharide (LPS) signaling and is required for the production of proinflammatory cytokines. We hypothesized that inhibition of hsp90 would prevent LPS-induced liver injury by decreasing proinflammatory cytokines. C57BL/6 mice were injected intraperitoneally with an hsp90 inhibitor, 17-dimethylamino-ethylamino-17-demethoxygeldanamycin (17-DMAG), and LPS. Parameters of liver injury, proinflammatory cytokines, and associated mechanisms were studied by in vivo and in vitro experiments. Inhibition of hsp90 by 17-DMAG prevented LPS-induced increases in serum alanine aminotransferase activity and significantly reduced serum tumor necrosis factor alpha (TNFa) and interleukin-6 (IL-6) protein as well as messenger RNA (mRNA) in liver. Enhanced DNA-binding activity of heat shock transcription factor 1 (HSF1) and induction of target gene heat shock protein 70 (molecular weight, 70 kDa) confirmed hsp90 inhibition in liver. 17-DMAG treatment decreased cluster of differentiation 14 mRNA and LPS-induced nuclear factor kappa light-chain enhancer of activated B cells (NF?B) DNA binding without affecting Toll-like receptor 4 mRNA in liver. Mechanistic studies revealed that 17-DMAG-mediated inhibition of TNFa showed no effect on LPS-induced NF?B promoter-driven reporter activity, but significantly decreased TNFa promoter-driven reporter activity. Chromatin immunoprecipitation assays showed that 17-DMAG enhanced HSF1 binding to the TNFa promoter, but not the IL-6 promoter, suggesting HSF1 mediated direct inhibition of TNFa, but not IL-6. We show that HSF1 indirectly regulates IL-6 by the induction of another transcription factor, activating transcription factor 3. Inhibition of HSF1, using small interfering RNA, prevented 17-DMAG-mediated down-regulation of NF?B-binding activity, TNFa, and IL-6 induction, supporting a repressive role for HSF1 on proinflammatory cytokine genes during hsp90 inhibition. Conclusion: Hsp90 inhibition in vivo reduces proinflammatory cytokines and prevents LPS-induced liver injury likely through repressive action of HSF1. Our results suggest a novel application for 17-DMAG in alleviating LPS-induced liver injury. (HEPATOLOGY 2011)
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