title: TNF-R55-specific form of human tumor necrosis factor-alpha induces collagenase gene expression by human skin fibroblasts.
abstract: Tumor necrosis factor-alpha (TNF-alpha) is a potent inhibitor of connective tissue formation. The cellular effects of TNF-alpha are mediated by two distinct cell-surface receptors, TNF-R55 and TNF-R75, both present on various types of cells, including fibroblasts. In this study we wanted to elucidate the role of TNF-R55 as a mediator of the connective tissue effects of TNF-alpha by using a mutant, TNF-R55-specific form of human TNF-alpha. This mutant TNF-alpha markedly induced collagenase and stromelysin-1 gene expression in dermal fibroblasts, the maximal activation (up to 42-fold) being 65%-89% of that noted with wild-type human TNF-alpha. In addition, TNF-R55-specific TNF-alpha suppressed type I collagen mRNA levels as potently as wild-type TNF-alpha (by 60%). The enhancement of collagenase gene expression by TNF-R55-specific TNF-alpha was augmented by simultaneous treatment of normal and scleroderma skin fibroblasts with interferon-gamma, indicating specific enhancement of TNF-R55 signaling pathway by interferon-gamma. These results show that stimulation of the TNF-R55 signaling pathway is sufficient for the inhibitory effects of TNF-alpha on extracellular matrix formation by dermal fibroblasts. It is conceivable that due to reduced systemic toxicity, TNF-R55-specific forms of human TNF-alpha may prove to be feasible in the therapy of fibrotic disorders.
authors.affiliation: Department of Medical Biochemistry, University of Turku, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Westermarck
authors.forename: L
authors.initials: L
authors.lastname: Häkkinen
authors.forename: W
authors.initials: W
authors.lastname: Fiers
authors.forename: V M
authors.initials: VM
authors.lastname: Kähäri
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000502:physiology*; D002478:Cells, Cultured; D017364:Collagenases / Q000235:genetics*; D005347:Fibroblasts / Q000502:physiology; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D012595:Scleroderma, Systemic / Q000473:pathology; D012867:Skin / Q000166:cytology; D012879:Skin Physiological Phenomena; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D015703:Antigens, CD; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D017364:Collagenases