title: TGF-β-mediated downregulation of microRNA-196a contributes to the constitutive upregulated type I collagen expression in scleroderma dermal fibroblasts.
abstract: Previous reports indicated the significance of the TGF-β signaling in the pathogenesis of systemic sclerosis. We tried to evaluate the possibility that microRNAs (miRNAs) play a part in the type I collagen upregulation seen in normal fibroblasts stimulated with exogenous TGF-β and systemic sclerosis (SSc) fibroblasts. miRNA expression profile was evaluated by miRNA PCR array and real-time PCR. The protein expression of type I collagen was determined by immunoblotting. In vivo detection of miRNA in paraffin section was performed by in situ hybridization. Several miRNAs were found to be downregulated in both TGF-β-stimulated normal fibroblasts and SSc fibroblasts compared with normal fibroblasts by PCR array. Among them, miR-196a expression was decreased in SSc both in vivo and in vitro by real-time PCR or in situ hybridization. In SSc fibroblasts, miR-196a expression was normalized by TGF-β small interfering RNA. miR-196a inhibitor leads to the overexpression of type I collagen in normal fibroblasts, whereas overexpression of the miRNA resulted in the downregulation of type I collagen in SSc fibroblasts. In addition, miR-196a was detectable and quantitative in the serum of SSc patients. Patients with lower serum miR-196a levels had significantly higher ratio of diffuse cutaneous SSc:limited cutaneous SSc, higher modified Rodnan total skin thickness score, and higher prevalence of pitting scars than those without. miR-196a may play some roles in the pathogenesis of SSc. Investigation of the regulatory mechanisms of type I collagen expression by miR-196a may lead to new treatments using miRNA.
authors.affiliation: Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Honda
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Jinnin
authors.forename: Ikko
authors.initials: I
authors.lastname: Kajihara
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Makino
authors.forename: Katsunari
authors.initials: K
authors.lastname: Makino
authors.forename: Shinichi
authors.initials: S
authors.lastname: Masuguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fukushima
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Manabu
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ihn
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000368:Aged; D001665:Binding Sites; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics; D020405:Dermis / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D010641:Phenotype; D012595:Scleroderma, Systemic / Q000235:genetics* / Q000473:pathology; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D020413:3' Untranslated Regions; D024042:Collagen Type I; C542543:MIRN196 microRNA, human; D035683:MicroRNAs; D016212:Transforming Growth Factor beta