Regulation of Stearoyl-Coenzyme A Desaturase 1 by trans-10,cis-12 Conjugated Linoleic Acid via SREBP1 in Primary Goat Mammary Epithelial Cells

Trans10, cis12 conjugated linoleic acid (t10c12-CLA) is a biohydrogenation intermediate in the rumen, which inhibits mammary fatty acid de novo synthesis of lactating dairy goats. However, the underlying molecular pathways of t10c12-CLA on milk lipid metabolism are not completely understood. The present study investigated the lipid regulation mechanisms on goat mammary epithelial cells (GMECs) in response to t10c12-CLA. Gene expression analysis indicated sterol regulatory element binding transcription factor1 (SREBF1) and its putative target gene stearoyl-CoA desaturase (SCD1) were down-regulated (fold change 0.33 ± 0.04, P < 0.05; and 0.19 ± 0.01, P < 0.01; respectively). Concentrations of cellular palmitoleic acid (C16:1) and oleic acid (C18:1) were decreased (1.12% ± 0.05% vs. 1.69% ± 0.11%, and 15.70% ± 0.44% vs. 24.97% ± 0.82%, respectively, P < 0.01), while linoleic acid (C18:2) was increased (5.00% ± 0.14% vs. 3.81% ± 0.25%, P < 0.05); and the desaturation indices of C16 and C18 were decreased in r...