title: MicroRNA-33b downregulates the differentiation and development of porcine preadipocytes.
abstract: Sterol regulatory element binding transcription factor (SREBF) is a key transcription regulator for lipid homeostasis. MicroRNA-33b (miR-33b) is embedded in intron 16 of porcine SREBF1 and is conserved among most mammals. Here, we investigated the effect of miR-33b on adipocyte differentiation and development in porcine subcutaneous pre-adipocytes (PSPA). PSPA were transiently transfected with miR-33b, and adipose differentiation was then induced. Delayed adipose differentiation and decreased lipid accumulation were observed in miR-33b-transfected PSPA. Computational predictions suggested that miR-33b may target early B cell factor 1 (EBF1), an adipocyte activator of lipogenesis regulators such as CCAAT-enhancer binding protein alpha (C/EBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). Both gene and protein expression of EBF1 were downregulated in miR-33b-transfected PSPA, followed by considerable decreases in the expression of C/EBPα and PPARγ and their downstream lipogenic genes. However, miR-33b transfection did not markedly affect mRNA and protein expression of SREBF1. We also investigated differences in the expression of miR-33b and lipogenic genes in subcutaneous fat tissues between 5-month-old crossbred gilts derived from Landrace (lean-type) and Meishan (fatty-type) boars. Landrace-derived crossbred gilts expressed more miR-33b and less lipogenic genes than did gilts derived from Meishan. Our results suggest that miR-33b affected the differentiation and development of PSPA by attenuating the lipogenic gene expression cascade through EBF1 to C/EBPα and PPARγ. The differential expression of miR-33b observed in crossbred gilts may in part account for differences in lipogenic gene expression and the fat:lean ratio between pig breeds.
authors.affiliation: Animal Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Nakajima
authors.forename: Koichi
authors.initials: K
authors.lastname: Chikuni
authors.forename: Misaki
authors.initials: M
authors.lastname: Kojima
authors.forename: Takashi
authors.initials: T
authors.lastname: Awata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mikawa
mesh_terms: D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics*; D000273:Adipose Tissue / Q000254:growth & development / Q000378:metabolism; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation; D050356:Lipid Metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D047495:PPAR gamma / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051780:Sterol Regulatory Element Binding Protein 1 / Q000096:biosynthesis / Q000235:genetics; D013552:Swine
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D004268:DNA-Binding Proteins; D035683:MicroRNAs; D047495:PPAR gamma; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1