Leptin represses matrix metalloproteinase-1 gene expression in LX2 human hepatic stellate cells.
OBJECTIVE
Collagen accumulation in liver fibrosis is due in part to decreased expression of matrix metalloproteinase (MMP)-1 relative to TIMP-1. LX-2 hepatic stellate cells produce increased amounts of collagen and tissue inhibitor of metalloproteinase (TIMP)-1 in response to leptin. The effect of leptin on MMP-1 production has not been reported.


METHODS
LX-2 cells were treated with leptin with or without inhibitors. We determined: phosphorylation of Janus kinase (JAK) 1 and -2, signal transducer and activator of transcription (STAT)3 and -5, extracellular signal-regulated kinase (ERK)1/2 and p38 by Western blot; H2O2 concentration by a colorimetric method; MMP-1 mRNA levels and stability by Northern blot; MMP-1 promoter activity as well as pro-MMP-1 by ELISA; and active MMP-1 by fluorescence.


RESULTS
LX-2 cells constitutively expressed the MMP-1 gene and leptin repressed the basal level of MMP-1 mRNA and its promoter activity. The repression was mediated by JAK/STAT pathway in synergism with JAK-mediated H2O2-dependent ERK1/2 and p38 pathways. ERK1/2 inhibited MMP-1 promoter activity, whereas p38 decreased the message stability, contributing to mRNA down-regulation. Inhibition of MMP-1 gene diminished secreted pro-MMP-1 and active MMP-1.


CONCLUSIONS
Leptin represses MMP-1 gene expression via the synergistic actions of the JAK/STAT pathway and JAK-mediated H2O2-dependent ERK1/2 and p38 pathways.
Cao
Qi
Q
Alcohol Research and Treatment Center, James J. Peters VA Medical Center, Bronx, and Mount Sinai School of Medicine, New York, NY 10029, USA.
Mak
Ki M
KM
Lieber
Charles S
CS
D001483:Base Sequence; D002374:Catalase / Q000378:metabolism; D002460:Cell Line; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D053612:Janus Kinases / Q000037:antagonists & inhibitors; D020738:Leptin / Q000494:pharmacology*; D008103:Liver Cirrhosis / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis / Q000235:genetics*; D008954:Models, Biological; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics; D050799:STAT5 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics; D020032:Tyrphostins / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007093:Imidazoles; D020738:Leptin; D020319:Oligodeoxyribonucleotides, Antisense; D011725:Pyridines; D012333:RNA, Messenger; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050799:STAT5 Transcription Factor; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D006861:Hydrogen Peroxide; D002374:Catalase; D053612:Janus Kinases; D020781:Matrix Metalloproteinase 1; C093642:SB 203580