title: miRNA-374 regulates dexamethasone-induced differentiation of primary cultures of porcine adipocytes.
abstract: To investigate the effect of glucocorticoid on adipocytes metabolism and miRNAs that may be involved in adipocyte differentiation, primary porcine preadipocytes were treated with 10-6 M dexamethasone and RU486 (a glucocorticoid receptor antagonist) for 48 h. PPAR-γ (peroxisome proliferators-activated receptor-γ), and C/EBP-β (CCTTA enhancer binding protein-β) gene and protein expression were measured. The expressions of miRNAs predicted to directly target C/EBP-β were determined, and the functions of the potential miRNAs were verified. The results showed that the triglyceride content in cultured adipocytes increased significantly after 10-6 M dexamethasone treatment for 48 h, whereas the cell viability did not differ among the four groups (
  
  
  METHODS
  10-6 M dexamethasone; 10-6 M RU486: 10-6 M dexamethasone+10-6 M RU486) (p>0.05). Cells treated with dexamethasone for 48 h significantly upregulated perilipin and PPAR-γ gene expression, and PPAR-γ protein expression was also significantly increased. However, C/EBP-β mRNA and protein expression levels were significantly decreased. Both miR-374a and miR-374b, targeting the C/EBP-β 3'-UTR (3'-untranslated region), were signiﬁcantly increased. Dual luciferase activity assay results indicated that miR-374a/b was directly recognised and bound to the 3'-UTR of C/EBP-β and thereby suppressed C/EBP-β gene expression. The present study showed that 10-6 M dexamethasone promotes lipid accumulation in primary cultures of porcine preadipocytes. PPAR-γ and C/EBP-β protein abundance showed differences after 48 h dexamethasone treatment; miR-374a/b may be involved in regulating of C/EBP-β expression. These results provide new targets for further regulation of porcine lipid metabolism.
authors.affiliation: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: S
authors.initials: S
authors.lastname: Pan
authors.forename: Y
authors.initials: Y
authors.lastname: Zheng
authors.forename: R
authors.initials: R
authors.lastname: Zhao
authors.forename: X
authors.initials: X
authors.lastname: Yang
mesh_terms: D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D003907:Dexamethasone / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D013552:Swine
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D035683:MicroRNAs; D047495:PPAR gamma; D003907:Dexamethasone