Interferon alpha increases metalloproteinase-13 gene expression through a polyomavirus enhancer activator 3-dependent pathway in hepatic stellate cells.
OBJECTIVE
To determine the effects of IFNalpha on MMP-13 gene expression in primary culture of hepatic stellate cells.


METHODS
We measured MMP-13 mRNA, MMP-13 protein, MMP-13 luciferase activity, binding of AP1 and PEA3 to DNA, and binding of PEA3 to Jak1 and Stat1.


RESULTS
IFNalpha increased MMP-13 mRNA, MMP-13 protein, and luciferase activity in cells transfected either with a luciferase plasmid driven by the MMP-13 promoter or with the same plasmid in which the AP1 binding site has been mutated. IFNalpha induced the binding of nuclear proteins to a radiolabeled PEA3 probe, but not to a AP1 probe. Supershift assays demonstrated that PEA3 and Stat1 are implicated in the formation of this complex. Immunoprecipitation assays showed that PEA3 interacts physically with Stat1 and that IFNalpha treatment increases this interaction. Downregulation of PEA3 or JAK1 with appropriated siRNAs or mutation of the PEA3 binding site in the MMP-13 promoter abrogated the effects of IFNalpha on MMP-13 gene expression. Finally, IFNalpha induced the binding of PEA3 to JAK1, as well as PEA3 tyrosine and serine phosphorylation.


CONCLUSIONS
IFNalpha determines the binding of PEA3 to JAK1 and its tyrosine phosphorylation. Activated PEA3 binds to MMP-13 promoter and activates its expression.
Díaz-Sanjuán
Teresa
T
Department of Gastroenterology, Research Center, Hospital Universitario 12 de Octubre, Avenida de Andalucia, s/n. Madrid, Spain.
García-Ruiz
Inmaculada
I
Rodríguez-Juan
Cristina
C
Muñoz-Yagüe
Teresa
T
Solís-Muñoz
Pablo
P
Solís-Herruzo
José A
JA
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects*; D055166:Hepatic Stellate Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016898:Interferon-alpha / Q000494:pharmacology*; D053613:Janus Kinase 1 / Q000378:metabolism; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D050794:STAT1 Transcription Factor / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015534:Trans-Activators / Q000378:metabolism*
D000998:Antiviral Agents; C510951:ETV4 protein, rat; D016898:Interferon-alpha; D050794:STAT1 Transcription Factor; C494081:Stat1 protein, rat; D015534:Trans-Activators; D012694:Serine; C507906:Jak1 protein, rat; D053613:Janus Kinase 1; D053509:Matrix Metalloproteinase 13