PPARγRegulates Genes Involved in Triacylglycerol Synthesis and Secretion in Mammary Gland Epithelial Cells of Dairy Goats

Abstract

To explore the function of PPARγin the goat mammary gland, we cloned the whole cDNA of the PPARγgene. Homology alignments revealed that the goat PPARγgene is conserved among goat, bovine, mouse, and human. Luciferase assays revealed that rosiglitazone enhanced the activity of the PPARγresponse element (PPRE) in goat mammary epithelial cells (GMECs). After rosiglitazone (ROSI) treatment of GMECs, there was a significant (P<0.05) increase in the expression of genes related to triacylglycerol synthesis and secretion:LPL, FASN, ACACA, PLIN3, FABP3, PLIN2, PNPLA2, NR1H3, SREBF1, andSCD. The decreases in expression observed after knockdown of PPARγrelative to the control group (Ad-NC) averaged 65%, 52%, 67%, 55%, 65%, 58%, 85%, 43%, 50%, and 24% forSCD, DGAT1, AGPAT6, SREBF1, ACACA, FASN, FABP3, SCAP, ATGL,andPLIN3, respectively. These results provide direct evidence that PPARγplays a crucial role in regulating the triacylglycerol synthesis and secretion in goat mammary cells and underscore the functional importance of PPARγin mammary gland tissue during lactation.