Effects of Leucine on Expression of Genes and Proteins Related with Milk Fat Synthesis in Bovine Mammary Epithelial Cells

ZHAO Yanli, CHEN Lu, SHI Binlin, GUO Xiaoyu, YAN Sumei

doi:10.3969/j.issn.1006-267x.2017.04.029

2017 , Vol. 29 >Issue 4: 1319 - 1326

DOI: https://doi.org/10.3969/j.issn.1006-267x.2017.04.029

Molecular Nutrition

Effects of Leucine on Expression of Genes and Proteins Related with Milk Fat Synthesis in Bovine Mammary Epithelial Cells

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Collage of Animal Science, Inner Mongolia Agriculture University, Hohhot 010018, China

Received date: 2016-09-28

Online published: 2017-04-14

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Abstract

The objects of this study were to study the effects of leucine (Leu) on expression of genes and proteins related with milk fat synthesis in bovine mammary epithelial cells (BMECs), in order to investigate the mechenism of Leu regulating milk fat synthesis. The third generation of BMECs were divided into six treatments with six replicates per treatment, and cultured in culture mediums with 0.45, 0.90, 1.80, 2.70, 3.60 and 7.20 mmol/L Leu, respectively. The triglyceride (TG) content, the relative expression levels of genes related with milk fat synthesis, as well as the protein relative expression levels of peroxisome proliferator-activated receptor-γ (PPARγ) and sterol regulatory element binding protein 1 (SREBP1) in BMECs after 48 h incubation at 37℃ and 5% CO₂ were detected. The results showed that the Leu concentration had no significant effect on TG content in BMECs (P>0.05). The optimal Leu concentration significantly up-regulated the gene expression of fatty acid synthase (FASN) and acetyl-CoA carboxylase A (ACACA) in BMECs (P<0.05). The higher gene relative expression level of FASN was observed in 1.80 to 2.70 mmol/L Leu treatments, and the higher gene relative expression level of ACACA was observed in 1.80 to 7.20 mmol/L Leu treatments. Leu concentration significantly increased the gene and protein expression of SREBP1 in BMECs (P<0.05), and the best promoting effect was observed in 1.80 mmol/L Leu treatment. Although Leu significantly inhibited the gene expression of fatty acid-binding protein 3 (FABP3), lipoprotein lipase (LPL), 1-acylglycerol-3-phosphate O-acyltransferase 6 (AGPAT6), mitochondria glycerol-3-phosphate acyltrandferase (GPAM) and butyrophilin subfamily 1 member A1 (BTN1A1)in BMECs (P<0.05), the higher inhibiting effect was only observed in high Leu concentration (3.60 to 7.20 mmol/L) treatments. Taken together, Leu concentration has a significant effect on the expression of genes related with milk fat synthesis and protein expression of PPARγ and SREBP1 in BMECs. The 1.80 to 2.70 mmol/L Leu has a better promoting effect on de novo fatty acid synthesis genes and SREBP1 protein expression, as well as little inhibiting effect on the expression of genes involved in TG synthesis and lipid droplet formation.

Key words： dairy cow; bovine mammary epithelial cells; leucine; milk fat

Cite this article

ZHAO Yanli, CHEN Lu, SHI Binlin, GUO Xiaoyu, YAN Sumei . Effects of Leucine on Expression of Genes and Proteins Related with Milk Fat Synthesis in Bovine Mammary Epithelial Cells[J]. Chinese Journal of Animal Nutrition, 2017 , 29(4) : 1319 -1326 . DOI: 10.3969/j.issn.1006-267x.2017.04.029

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