Leflunomide attenuates hepatocyte injury by inhibiting Kupffer cells.
OBJECTIVE
To investigate the importance of direct contact between Kupffer cells (KCs) and hepatocytes (HCs) during hepatic inflammatory responses, and the effect of leflunomide's active metabolite, A(771726), on cytokines in KCs, HCs and KC cocultures (DC cocultures).


METHODS
KCs and HCs in liver were isolated by digestion with pronase and collagenase. Lipopolysaccharide (LPS)-induced inflammatory response in monocultures of rat HCs and KCs was compared with that in DC cocultures. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) concentrations in different culture supernatants were measured with ELISA. TNF-alpha mRNA in KCs of inflammatory liver injury was analyzed with reverse transcriptase polymerase chain reaction (RT-PCR).


RESULTS
DC cocultures strongly exhibited the production of TNF-alpha and IL-1 compared with other cultures, and these cytokines were mainly produced by KCs, especially by activated KCs. Time course studies revealed an increased production of TNF-alpha preceding the IL-1 production, suggesting that increased TNF-alpha levels could be involved in the increase of IL-1 production. Leflunomide's active metabolite, A(771726), had significantly inhibitory effect on TNF-alpha and IL-1 at protein and transcription levels, and the reduced production of IL-1 by A(771726) was associated with the inhibitory action of A(771726 ) on TNF-alpha.


CONCLUSIONS
Leflunomide can inhibit hepatocyte damage by inhibiting proinflammatory cytokine release from KCs.
Yao
Hong-Wei
HW
Zhejiang Respiratory Drugs Research Laboratory, State Drug Administration of China, School of Medicine, Zhejiang University, Hangzhou, China.
Li
Jun
J
Chen
Ji-Qiang
JQ
Xu
Shu-Yun
SY
D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D002450:Cell Communication / Q000187:drug effects; D002478:Cells, Cultured; D003437:Crotonates; D006505:Hepatitis / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D022781:Hepatocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D006885:Hydroxybutyrates / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007375:Interleukin-1 / Q000378:metabolism; D007555:Isoxazoles / Q000494:pharmacology*; D007728:Kupffer Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology*; D000077339:Leflunomide; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009570:Nitriles; D051381:Rats; D017207:Rats, Sprague-Dawley; D014052:Toluidines; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000814:Aniline Compounds; D003437:Crotonates; D006885:Hydroxybutyrates; D007166:Immunosuppressive Agents; D007375:Interleukin-1; D007555:Isoxazoles; D008070:Lipopolysaccharides; D009570:Nitriles; D014052:Toluidines; D014409:Tumor Necrosis Factor-alpha; C527525:teriflunomide; D000077339:Leflunomide