4-hydroxynonenal decreases interleukin-6 expression and protein production in primary rat Kupffer cells by inhibiting nuclear factor-kappaB activation.
Kupffer cells have been documented to play an important role in the early events of liver injury and regeneration by releasing biologically active mediators such as interleukin-6 (IL-6). 4-Hydroxy-trans-2-nonenal (4-HNE), a major end product of lipid peroxidation, has multiple cytotoxic effects and is implicated in chemical-induced liver injury. Consequently, the purpose of this study was to evaluate the ability of 4-HNE to modulate IL-6 production in isolated primary rat Kupffer cells. 4-HNE (0.1-10 microM) reduced both lipopolysaccharide (LPS)-induced IL-6 protein production and mRNA levels. The role of nuclear factor-kappaB (NF-kappaB) in IL-6 induction was elucidated using Kupffer cells transduced in vitro with a recombinant adenovirus containing a IkappaBalpha super-repressor resistant to phosphorylation and degradation (Ad5IkappaB). Using this system, LPS-induced IL-6 protein production was inhibited by 65% in Ad5IkappaB-infected cells. The treatment of Kupffer cells for 1 h with 4-HNE followed by stimulation for 1 h with LPS (500 ng/ml) resulted in a concentration-dependent decrease in NF-kappaB activation. Similarly, decreased NF-kappaB activity in these cells paralleled a reduction in IkappaBalpha mRNA levels. Furthermore, upon LPS stimulation, 4-HNE stabilized IkappaBalpha, which corresponded to a decrease in phosphorylated IkappaBalpha. At lower 4-HNE concentrations (0-5 microM), interactions between p65 and IkappaBalpha proteins were maintained as detected by immunoprecipitation-immunoblot analyses. In conclusion, these data suggest that 4-HNE inhibits IL-6 production in rat Kupffer cells by preventing activation of the NF-kappaB pathway and suppressing IkappaBalpha phosphorylation. These results have functional implications in that 4-HNE may interfere with the ability of Kupffer cells to produce cytokines proposed to play an important role in liver regeneration.
Luckey
Stephen W
SW
Molecular Toxicology and Environmental Health Sciences Program, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA.
Taylor
Melinda
M
Sampey
Brante P
BP
Scheinman
Robert I
RI
Petersen
Dennis R
DR
D000257:Adenoviridae Infections / Q000378:metabolism; D000447:Aldehydes / Q000494:pharmacology*; D000818:Animals; D001711:Biotransformation / Q000187:drug effects; D015153:Blotting, Western; D002478:Cells, Cultured; D003470:Culture Media; D016207:Cytokines / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D003864:Depression, Chemical; D015850:Interleukin-6 / Q000096:biosynthesis*; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009841:Oligonucleotides; D010766:Phosphorylation; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats
D000447:Aldehydes; D003470:Culture Media; D016207:Cytokines; D015850:Interleukin-6; D016328:NF-kappa B; D009841:Oligonucleotides; D012333:RNA, Messenger; D004247:DNA; C027576:4-hydroxy-2-nonenal