Regulation of peroxisome proliferator-activated receptor gamma on milk fat synthesis in dairy cow mammary epithelial cells.
Peroxisome proliferator-activated receptor gamma (PPARγ) participates in lipogenesis in rats, goats, and humans. However, the exact mechanism of PPARγ regulation on milk fat synthesis in dairy cow mammary epithelial cells (DCMECs) remains largely unexplored. The aim of this study was to investigate the role of PPARγ regarding milk fat synthesis in DCMECs and to ascertain whether milk fat precursor acetic acid and palmitic acid could interact with PPARγ signaling to regulate milk fat synthesis. For this study, we examined the effects of PPARγ overexpression and gene silencing on cell growth, triacylglycerol synthesis, and the messenger RNA (mRNA) and protein expression levels of genes involved in milk fat synthesis in DCMECs. In addition, we investigated the influences of acetic acid and palmitic acid on the mRNA and protein levels of milk lipogenic genes and triacylglycerol synthesis in DCMECs transfected with PPARγ small interfering RNA (siRNA) and PPARγ expression vector. The results showed that when PPARγ was silenced, cell viability, proliferation, and triacylglycerol secretion were obviously reduced. Gene silencing of PPARγ significantly downregulated the expression levels of milk fat synthesis-related genes in DCMECs. PPARγ overexpression improved cell viability, proliferation, and triacylglycerol secretion. The expression levels of milk lipogenic genes were significantly increased when PPARγ was overexpressed. Acetic acid and palmitic acid could markedly improve triacylglycerol synthesis and upregulate the expression levels of PPARγ and other lipogenic genes in DCMECs. These results suggest that PPARγ is a positive regulator of milk fat synthesis in DCMECs and that acetic acid and palmitic acid could partly regulate milk fat synthesis in DCMECs via PPARγ signaling.
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.|College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, 150040, People's Republic of China.
Lili
L
Liu
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Ye
Y
Lin
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Lixin
L
Liu
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Lina
L
Wang
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Yanjie
Y
Bian
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Xuejun
X
Gao
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, People's Republic of China. qzli@neau.edu.cn.
Qingzhang
Q
Li
D019342:Acetic Acid / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003612:Dairying; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D008055:Lipids / Q000096:biosynthesis*; D050155:Lipogenesis / Q000187:drug effects / Q000235:genetics; D008321:Mammary Glands, Animal / Q000166:cytology*; D008892:Milk / Q000737:chemistry*; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D019308:Palmitic Acid / Q000494:pharmacology; D014280:Triglycerides / Q000378:metabolism
D008055:Lipids; D047495:PPAR gamma; D014280:Triglycerides; D019308:Palmitic Acid; D019342:Acetic Acid
Acetic acid; Dairy cow mammary epithelial cells; Milk fat synthesis; PPARγ; Palmitic acid