title: Activation of p70 ribosomal protein S6 kinase is an essential step in the DNA damage-dependent signaling pathway responsible for the ultraviolet B-mediated increase in interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3) protein levels in human dermal fibroblasts.
abstract: Ultraviolet B (UVB) irradiation has been shown to stimulate the expression of matrix-degrading metalloproteinases via generation of DNA damage and/or reactive oxygen species. Matrix-degrading metalloproteinases promote UVB-triggered detrimental long term effects like cancer formation and premature skin aging. Here, we were interested in identifying components of the signal transduction pathway that causally link UVB-mediated DNA damage and induction of matrix-degrading metalloproteinase (MMP)-1/interstitial collagenase and MMP-3/stromelysin-1 in human dermal fibroblasts in vitro. The activity of p70 ribosomal S6 kinase, a downstream target of the FK506-binding protein-12/rapamycin-associated protein kinase (FRAP) kinase (RAFT1, mTOR), was identified to be 4.8 +/- 0.8-fold, and MMP-1 and MMP-3 protein levels 2.4- and 11.5-fold increased upon UVB irradiation compared with mock-irradiated controls. The FRAP kinase inhibitor rapamycin and the DNA repair inhibitor aphidicolin significantly suppressed the UVB-mediated increase in p70 ribosomal S6 kinase activity by 50-65% and MMP-1 and MMP-3 protein levels by 34-68% and 42-88% compared with UVB-irradiated fibroblasts. By contrast, the interleukin-1beta-mediated increase in MMP-1 and MMP-3 protein levels could not be suppressed by rapamycin. Collectively, our data suggest that the FRAP-controlled p70 ribosomal S6 kinase is an essential component of a DNA damage-dependent, but not of the interleukin-1/cell membrane receptor-dependent signaling.
authors.affiliation: Department of Dermatology, University of Cologne, D-50924 Cologne, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Brenneisen
authors.forename: J
authors.initials: J
authors.lastname: Wenk
authors.forename: M
authors.initials: M
authors.lastname: Wlaschek
authors.forename: T
authors.initials: T
authors.lastname: Krieg
authors.forename: K
authors.initials: K
authors.lastname: Scharffetter-Kochanek
mesh_terms: D000595:Amino Acid Sequence; D016590:Aphidicolin / Q000494:pharmacology; D002478:Cells, Cultured; D004249:DNA Damage / Q000235:genetics*; D004789:Enzyme Activation / Q000528:radiation effects; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D020104:Immunophilins / Q000378:metabolism; D007375:Interleukin-1 / Q000494:pharmacology; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D008969:Molecular Sequence Data; D011740:Pyrimidine Dimers / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism*; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D007375:Interleukin-1; D011740:Pyrimidine Dimers; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D016590:Aphidicolin; D019893:Ribosomal Protein S6 Kinases; D019278:Matrix Metalloproteinase 3; D020781:Matrix Metalloproteinase 1; D022021:Tacrolimus Binding Proteins; D020104:Immunophilins; D020123:Sirolimus