title: SCD1 Alters Long-Chain Fatty Acid (LCFA) Composition and Its Expression Is Directly Regulated by SREBP-1 and PPARγ 1 in Dairy Goat Mammary Cells.
abstract: Stearoyl-CoA desaturase 1 (SCD1) is a key enzyme for the synthesis of the monounsaturated fatty acids (MUFA) palmitoleic acid and oleic acid. In non-ruminant species, SCD1 expression is known to be tightly regulated by a variety of transcription factors. Although the role of SCD1 and the transcriptional regulatory mechanism by SREBP-1 and PPARs in other species is clear, changes in lipid metabolism related to SCD1 and via the regulation of SREBP-1 or PPARG1 in ruminant mammary tissue remain largely unknown. Here, we demonstrated that SCD1 expression in goat mammary tissue is higher during lactation than the dry period. Overexpression of SCD1 increased the intracellular MUFA content and lipid accumulation, whereas SCD1 silencing resulted in a significant decrease in oleic acid concentration and triacylglycerol (TAG) accumulation. The overexpression of SREBF1 in goat mammary epithelial cells (GMEC) enhanced SCD1 expression and its promoter activity, but that effect was abolished when SREBF1 was silenced. Furthermore, deletion of sterol regulatory element (SRE) and the nuclear factor (NF-Y)-binding sites within a -1713 to +65-base pair region of the SCD1 promoter completely abolished SREBP-1-induced SCD1 transcription. Otherwise, PPARG1 overexpression also stimulated the expression of SCD1 and its transcriptional activity directly via a PPAR response element (PPRE) in the SCD1 promoter. Together, these results indicate that SCD1 could markedly affect the fatty acid composition and rate of TAG synthesis through direct regulation via SREBP-1 and PPARG1, hence, underscoring an important role of the enzyme and this transcription regulator in controlling mammary gland lipid synthesis in the goat. J. Cell. Physiol. 232: 635-649, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Yao
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Luo
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Qiuya
authors.initials: Q
authors.lastname: He
authors.affiliation: College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, P. R. China.
authors.forename: Hengbo
authors.initials: H
authors.lastname: Shi
authors.affiliation: College of Animal Science and Technology, Henan University of Animal Husbandry and Economy, Zhengzhou, Henan, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Huifen
authors.initials: H
authors.lastname: Xu
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P. R. China.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Yi
authors.affiliation: Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of IIlinois, Urbana, Illinois.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Loor
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D023081:CCAAT-Binding Factor / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D006041:Goats / Q000235:genetics*; D007774:Lactation / Q000235:genetics; D050356:Lipid Metabolism / Q000235:genetics; D008321:Mammary Glands, Animal / Q000166:cytology*; D008954:Models, Biological; D047495:PPAR gamma / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020218:Response Elements / Q000235:genetics; D013230:Stearoyl-CoA Desaturase / Q000235:genetics / Q000378:metabolism*; D051780:Sterol Regulatory Element Binding Protein 1 / Q000378:metabolism*; D014162:Transfection; D014280:Triglycerides / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
chemical_list: D023081:CCAAT-Binding Factor; D005227:Fatty Acids; D047495:PPAR gamma; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051780:Sterol Regulatory Element Binding Protein 1; D014280:Triglycerides; D013230:Stearoyl-CoA Desaturase