Effect of interaction between leucine and acetate on the milk protein synthesis in bovine mammary epithelial cells

Abstract

The interaction between Leucine (Leu) and acetate affecting milk protein synthesis in the bovine mammary epithelial cells (BMECs), and underlying the molecular mechanisms are not well understood. The objectives of this study were to investigate the effect of Leu, acetate, and their interaction on the expression of genes involved in milk protein synthesis, and JACK2/STAT5, mTOR and AMP-activated protein kinase (AMPK) signaling pathway. The study was a 2 × 6 factorial arrangement with treatments: Leu concentration (0.45 and 1.8 mM) and acetate concentration (0, 4, 6, 8, 10, and 12 mM). The results showed that 1.8 mM Leu or 8-10 mM acetate had positive effect on ATP content, the expression of casein genes, JACK2/STAT5 and phosphorylation of mTOR pathway, but reduced AMPK phosphorylation. Leu at 1.8mM had a positive effect on the up-regulation of acetate on ATP content, the expression of CSN1S1, CSN2, CSN3, and JACK2, the expression and phosphorylation of eukaryotic initiation factor 4E, p70 ribosomal protein S6 kinase-1, and mTOR, but reducing AMPK phosphorylation. The results suggest that acetate, Leu, and their interaction have effect on milk protein synthesis through the JACK2/STAT5, mTOR, and AMPK pathway. Acetate addition up-regulated the effect of Leu on milk protein synthesis, and Leu facilitated the up-regulation of acetate on milk protein synthesis through these pathways. K E Y W O R D Sacetate, bovine mammary epithelial cell, interaction, Leucine, milk protein How to cite this article: Zhao Y, Yan S, Chen L, Shi B, Guo X.Effect of interaction between leucine and acetate on the milk protein synthesis in bovine mammary epithelial cells. Anim Sci

Effects of L-Histidine and Sodium Acetate on β-Casein Expression in Nutrient-Restricted Bovine Mammary Epithelial Cells

“…This is consistent with our finding that GLUT1 exression was increased in 100%DIF compared to 99%DIF. Zhao et al (2019) reported an increase of cellular ATP concents by the supplementation of Ace. Ace was not affected by the GLUT1 levels in this study; however, it may be a potential energy source in mammary epithelial levels.…”

“…Thus, 0.15 mM His was selected for the verification of its combination effect with Ace. The supplementation of Ace presented an increase of the β-casein mRNA level in pbMECs cultured with DMEM/F12 [ 13 ]. This is consistent with our results when 0.15–0.6 mM Ace was supplemented to the MAC-T cells.…”

“…The results suggest that a supply of Ace with His has stimulatory effects on protein synthesis. Some synergistic effects on β-casein expression were reported when Ace was treated with leucine [ 13 ] or methionine [ 25 ] in nutrient-abundant conditions. Although the protein concentration in the cultured medium was increased after the treatment with a combination of Ace and His, such a combination did not show a synergistic effect on β-casein mRNA expression under the 100%DIF condition.…”

“…This might be explained by the different medium conditions: AA-devoid medium in previous studies [ 4 , 11 ] and DMEM/F12 in the present study. The supplementation of 4–12 mM Ace increased the mTOR mRNA levels in pbMECs [ 13 ]. In the present study, 0.15 mM Ace might have been a dose that was too low to increase the mTOR expression.…”

“…Protein synthesis is a highly energy-demanding process. Acetate (Ace) is a precursor of milk fat and an energy source for ruminants, and its ability to stimulate milk protein synthesis have been reported in mammary epithelial levels [ 12 , 13 ]. Thus, His and Ace might be useful for verifying their effects on β-casein mRNA expression in mammary epithelial cells under NR conditions.…”