title: [Synergistic action of 4-hydroxynonenal and tumor necrosis factor involving the NF-kB/IkBa signaling pathway in alcohol-induced liver injury].
abstract: OBJECTIVE
  To investigate the effects and mechanism of intracellular 4-hydroxynonenal (4-HNE) accumulation on tumor necrosis factor (TNF)-induced hepatotoxicity in alcoholic liver disease (ALD).
  
  
  METHODS
  An ALD model was established in male C57BL/6 mice (6-8 weeks old) by feeding an ethanol-containing diet for 5 weeks; mice given regular (non-ethanol) diet served as controls. ALD-related changes in 4-HNE and TNF levels were detected by western blotting. The underlying mechanisms of this molecular effect were examined by pre-treating HepG2 cells with 4-HNE followed by exposure to various concentrations of TNF. Effects on cell death were evaluated by MTT assay. Effects on TNF-mediated upstream factors' expression were detected by ELISA, western blotting, and real-time PCR. Effects on the TNF-induced inhibitor of NF-kB (IkBa) activity (phosphorylation status) and its formation of adducts were detected by western blotting and immunoprecipitation.
  
  
  RESULTS
  ALD mice showed increased hepatic 4-HNE and TNF levels, and the increases were associated with extent of liver injury. Cell culture studies revealed that 4-HNE, at non-toxic concentrations, sensitized hepatocytes to TNF killing, which was associated with suppressed NF-kB trans activity. Furthermore, 4-HNE prevented phosphorylation of IkBa without affecting upstream IkB kinase activity. The ALD-enhanced 4-HNE content was found to associated with increased formation of 4-HNE-IkBa adduction for both the 4-HNE - treated hepatocytes in culture and in the livers of ALD mice.
  
  
  CONCLUSIONS
  Alcohol-induced increase in 4-HNE accumulation represents a potent and clinically relevant mechanism of sensitizing hepatocytes to TNF-induced toxicity. These data support the notion that decreasing or eliminating accumulated intracellular 4-HNE can serve as a potential therapeutic option for ALD.
authors: Life Sciences College of Zhejiang Chinese Medical University, Cell Biology Institute of Zhejiang Chinese Medical University, Hangzhou 310053, China.
authors: Zhong-yan
authors: ZY
authors: Du
authors: Jia
authors: J
authors: Gao
authors: Wei-xi
authors: WX
authors: Wang
authors: Chen-hui
authors: CH
authors: Yu
authors: Xiao-bing
authors: XB
authors: Dou
mesh_terms: D000447:Aldehydes / Q000378:metabolism*; D000818:Animals; D000431:Ethanol / Q000633:toxicity; D056945:Hep G2 Cells; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D008108:Liver Diseases, Alcoholic / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D000447:Aldehydes; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D000431:Ethanol; C027576:4-hydroxy-2-nonenal