title: Inhibition of cytokine-induced matrix metalloproteinase 9 expression by peroxisome proliferator-activated receptor alpha agonists is indirect and due to a NO-mediated reduction of mRNA stability.
abstract: Rat renal mesangial cells express high levels of matrix metalloproteinase 9 (MMP-9) in response to inflammatory cytokines such as interleukin 1beta (IL-1beta). We tested whether ligands of the peroxisome proliferator-activated receptor (PPARalpha) could influence the cytokine-induced expression of MMP-9. Different PPARalpha agonists dose-dependently inhibited the IL-1beta-triggered increase in gelatinolytic activity mainly by decreasing the MMP-9 steady-state mRNA levels. PPARalpha agonists on their own had no effects on MMP-9 mRNA levels and gelatinolytic activity. Surprisingly, the reduction of MMP-9 mRNA levels by PPARalpha activators contrasted with an amplification of cytokine-mediated MMP-9 gene promoter activity and mRNA expression. The potentiation of MMP-9 promoter activity functionally depends on an upstream peroxisome proliferator-responsive element-like binding site, which displayed an increased DNA binding of a PPARalpha immunopositive complex. In contrast, the IL-1beta-induced DNA-binding of nuclear factor kappaB was significantly impaired by PPARalpha agonists. Most interestingly, in the presence of an inducible nitric-oxide synthase (iNOS) inhibitor, the PPARalpha-mediated suppression switched to a strong amplification of IL-1beta-triggered MMP-9 mRNA expression. Concomitantly, activators of PPARalpha potentiated the cytokine-induced iNOS expression. Using actinomycin D, we found that NO, but not PPARalpha activators, strongly reduced the stability of MMP-9 mRNA. In contrast, the stability of MMP-9 protein was not affected by PPARalpha activators. In summary, our data suggest that the inhibitory effects of PPARalpha agonists on cytokine-induced MMP-9 expression are indirect and primarily due to a superinduction of iNOS with high levels of NO reducing the half-life of MMP-9 mRNA.
authors.affiliation: Pharmazentrum Frankfurt, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt am Main D-60590, Germany. w.eberhardt@em.uni-frankfurt.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eberhardt
authors.forename: El-Sayed
authors.initials: el-S
authors.lastname: Akool
authors.forename: Jorg
authors.initials: J
authors.lastname: Rebhan
authors.forename: Stefan
authors.initials: S
authors.lastname: Frank
authors.forename: Karl-Friedrich
authors.initials: KF
authors.lastname: Beck
authors.forename: Rochus
authors.initials: R
authors.lastname: Franzen
authors.forename: Farid M A
authors.initials: FM
authors.lastname: Hamada
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003001:Cloning, Molecular; D016207:Cytokines / Q000037:antagonists & inhibitors*; D004247:DNA / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000502:physiology*; D009841:Oligonucleotides / Q000494:pharmacology; D020025:Peroxisome Proliferators / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists*; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D014157:Transcription Factors / Q000819:agonists*; D014158:Transcription, Genetic; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D009841:Oligonucleotides; D020025:Peroxisome Proliferators; D011500:Protein Synthesis Inhibitors; D011743:Pyrimidines; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D014157:Transcription Factors; D003609:Dactinomycin; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; C006253:pirinixic acid; D004247:DNA; D020780:Matrix Metalloproteinase 9