GSE172056
Expression profiling of microRNA from peripheral blood of dairy cows in response to Staphylococcus aureus-infected mastitis
Purpose: To identify the expression profiling of miRNA in peripheral blood of dairy cows in response to S. aureus-infected mastitis and explore the biomarkers for early diagnosis of S. aureus-infected mastitis.  Methods: RNAseq technology was used to determine the expression profiles of microRNA (miRNA) from peripheral blood of Chinese Holstein cows infected with S. aureus at 0, 1, 3, 5, and 7 days. Results: Ttal of 288 differentially expressed miRNAs (DIE-miRNA) including 108 known and 180 novel predicted miRNAs, involved in 10 immune system-related signaling pathways. Compare with the 0 dpi, the number of DIE-miRNAs in 1, 3, 5, and 7 dpi groups were 12, 21, 75, and 48, respectively. It was also found that the expression variation of up-regulated expression of miR-320a, miR-19a, and miR-19b as well as down-regulated expression of miR-143, miR-205, and miR-24 reached a significant level on the 5 dpi and 7 dpi. However, at different times after S. aureus infection, miR-1301 was significantly up-regulated in peripheral blood. miR-2284r was significantly down-regulated. Conclusion: miR-1301 and miR-2284r might be the new blood biomarkers for S. aureus-infected dairy cow mastitis. The above results laid a new foundation for the research and development of molecular diagnosis and biological therapy technology for S. aureus-infected mastitis in dairy cow. Overall design: The experimental animals in this study were lactating 2 to 3-year-old half-sib Chinese Holstein cows, which were obtained from a farm in Yangling, Shaanxi, China. They had the same feeding and management environment. The body conditions of the dairy cows were measured three weeks before the experiment. All individuals had no symptoms of mastitis, and the somatic cell count (SCC) of milk was less than 200,000/mL. The udders and mammilla of the experimental dairy cows were cleaned and sterilized with 75% ethanol, and 5 mL of 10^5 CFU/mL S. aureus (ATCC 25923) suspension was injected into the udders of the experimental dairy cows through the mammary duct with a milk-passing needle. On the 7th day of induction, the mammary gland tissues were collected using painless surgery for hematoxylin-eosin (HE) staining and pathological analysis for mastitis model identification. On the day 0 (control), 1, 3, 5, and 7 after S. aureus infection, peripheral blood was collected from the jugular vein, and blood samples of different individuals with the same induction time were mixed and used to perform RNAseq.