title: Interaction between the aryl hydrocarbon receptor and retinoic acid pathways increases matrix metalloproteinase-1 expression in keratinocytes.
abstract: Exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) results in a variety of pathological lesions in humans via activation of the aryl hydrocarbon receptor (AhR) pathway. It has become apparent that this pathway interacts with a variety of signaling pathways that are believed to be involved in mediating TCDD/AhR biological effects. Our hypothesis is that TCDD mediates these pathological lesions by directly altering the expression of genes involved in matrix deposition and remodeling and that the retinoic acid signaling pathway is involved in modulating TCDD-induced effects. Therefore, we examined the effect of TCDD and all-trans retinoic acid (atRA) on the expression of matrix metalloproteinase-1 (MMP-1, interstitial collagenase), one of the proteolytic enzymes that degrade type I collagen, in normal human keratinocytes. The data show that TCDD exposure results in increased MMP-1 expression in keratinocytes that is further enhanced by co-treatment with all-trans retinoic acid. TCDD-induced expression of MMP-1 appears to be mediated through two AP-1 elements in the proximal promoter of the MMP-1 gene. However, retinoic acid-mediated induction of keratinocyte MMP-1 is a result of both promoter activation and increased mRNA stability. These findings are the first to demonstrate TCDD-induced expression of MMP-1 and to demonstrate interactions between the TCDD/AhR and retinoic acid pathways on MMP-1 expression.
authors.affiliation: Department of Biochemistry and Microbiology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA.
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Murphy
authors.forename: Caren M
authors.initials: CM
authors.lastname: Villano
authors.forename: Ruth
authors.initials: R
authors.lastname: Dorn
authors.forename: Lori A
authors.initials: LA
authors.lastname: White
mesh_terms: D015152:Blotting, Northern; D002478:Cells, Cultured; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology*; D020781:Matrix Metalloproteinase 1 / Q000235:genetics*; D017396:Plasminogen Activator Inhibitor 2 / Q000235:genetics; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D018336:Receptors, Aryl Hydrocarbon / Q000502:physiology*; D018168:Receptors, Retinoic Acid / Q000502:physiology; D047488:Retinoid X Receptors; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D017396:Plasminogen Activator Inhibitor 2; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D014212:Tretinoin; D019363:Cytochrome P-450 CYP1A1; D020781:Matrix Metalloproteinase 1