title: Induction by IL-1 beta of tissue inhibitor of metalloproteinase-1 in human orbital fibroblasts: modulation of gene promoter activity by IL-4 and IFN-gamma.
abstract: Thyroid-associated ophthalmopathy (TAO), an autoimmune component of Graves' disease, is associated with profound connective tissue remodeling and fibrosis that appear to involve the selective activation of orbital fibroblasts. Accumulation of extracellular matrix molecules is a hallmark of this process. Here we report that orbital fibroblasts treated with IL-1beta express high levels of tissue inhibitor of metalloproteinase-1 (TIMP-1), an important modulator of matrix metalloproteinase activity. These high levels are associated with increased TIMP-1 activity. The induction is mediated at the pretranslational level and involves activating the TIMP-1 gene promoter. IL-1beta activates the ERK 1/2 pathway in these fibroblasts and interrupting this signaling either with PD98059, a chemical inhibitor of MEK, or by transfecting cells with a dominant negative ERK 1 plasmid results in the attenuation of TIMP-1 induction. Surprisingly, treatment with IL-4 or IFN-gamma could also block the IL-1beta induction by attenuating TIMP-1 gene promoter activity. These findings suggest that TIMP-1 expression in orbital fibroblasts following activation with IL-1beta could represent an important therapeutic target for modifying the proteolytic environment. This might alter the natural course of tissue remodeling in TAO.
authors.affiliation: Division of Molecular Medicine, Department of Medicine, Harbor-University of California Los Angeles Medical Center, Torrance, CA 90502, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Han
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Smith
mesh_terms: D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D004789:Enzyme Activation / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism / Q000502:physiology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D006111:Graves Disease / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology*; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D015847:Interleukin-4 / Q000502:physiology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D009915:Orbit; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects / Q000276:immunology
chemical_list: D007375:Interleukin-1; D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D015847:Interleukin-4; D003907:Dexamethasone; D007371:Interferon-gamma; D048049:Extracellular Signal-Regulated MAP Kinases; D020780:Matrix Metalloproteinase 9