Abstract #M152

# M152
MicroRNAs miR-181a and miR-194 can regulate the biosynthesis of milk fat and protein by targeting ACSL1 and STAT5a.
S. Lian1,2, X. M. Nan2,3, D. P. Bu*2,4, F. Wang2, J. R. Guo1, 1College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang, China, 2State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China, 3Synergetic Innovation Center of Food Safety and Nutrition, Harbin, China, 4CAAS-ICRAF Joint Lab on Agroforestry and Sustainable Animal Husbandry, Beijing, China.

MicroRNAs (miRNA) are a class of small noncoding RNAs and act as important post-transcriptional regulators of gene expression. ACSL1 is an important gene in milk lipid synthesis and STAT5a is one of the key genes in milk protein synthesis. In a previous study dealing with incubation of stearic acid in bovine mammary epithelial cells, an opposite expression pattern was observed between ACSL1 and miR-181a, STAT5a and miR-194. ACSL1 and STAT5a were also predicted as potential target genes of miR-181a and miR-194 respectively by TargetScan and PicTar, which are the most popular target gene prediction softwares. The objective of this work was to determine the potential function of miR-181a and miR-194 on milk fat and protein synthesis by defining the regulatory relationship between miR-181a and ACSL1, miR-194 and STAT5A. In the study, primary bovine mammary epithelial cells harvested from mid-lactation cows were cultured in DMEM/F12 medium added with 10% FBS and lactational hormones. Cells were transfected with miR-181a mimic, miR-181a inhibitor, miR-194 mimic and miR-194 inhibitor, and non-transfected cells were set as control. After an 48 h treatment, expression of miR-181a, miR-194, ACSL1, STAT5a were determined by real-time reverse-transcription PCR. The results showed that the overexpression of miR-181a and miR-194 inhibited the expression of ACSL1 and STAT5a respectively (P < 0.05), while the downregulation of the 2 miRNAs increased ACSL1 and STAT5a expression (P < 0.05). Therefore suggesting that miR-181a and miR-194 may play important roles in milk fat and protein synthesis.

Key Words: miR-181a, miR-194, bovine mammary epithelial cells