title: Inhibition of microRNA122 decreases SREBP1 expression by modulating suppressor of cytokine signaling 3 expression.
abstract: While inhibition of microRNA122 (miR122) function in vivo results in reduced serum cholesterol and fatty acid levels, the molecular mechanisms underlying the link between miR122 function and lipid metabolism remains unclear. Because the expression of SREBP1, a central transcription factor involved in lipid metabolism, is known to be increased by suppressor of cytokine signaling 3 (SOCS3) expression, and because we previously found that SOCS3 expression is regulated by miR122, in this study, we examined the correlation between miR122 status and the expression levels of SOCS3 and SREBP1. SREBP1 expression decreased when SOCS3 expression was reduced by miR122 silencing in vitro. Conversely, SREBP1 expression in miR122-silenced cells was restored by enforced expression of SOCS3. Such correlations were observed in human liver tissues with different miR122 expression levels. These signaling links may explain one of the molecular mechanisms linking inhibition of miR122 function or decreased expression of miR122 to decreased fatty acid and cholesterol levels, in the inhibition of miR122 function, or in pathological status in chronic liver diseases.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Shibata
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kishikawa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Otsuka
authors.forename: Motoko
authors.initials: M
authors.lastname: Ohno
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Akemi
authors.initials: A
authors.lastname: Takata
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Yoshida
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D020868:Gene Silencing / Q000502:physiology; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic / Q000502:physiology; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C531907:MIRN122 microRNA, human; D035683:MicroRNAs; C106644:SOCS3 protein, human; C497387:SREBF1 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins
keywords: Expression regulation; Liver; SOCS3; SREBP; microRNA