Expression of exosomal microRNAs in bovine serum with clinical or subclinical mastitis

Bovine mastitis causes changes in the serum exosomal miRNAs expression. Serum samples from healthy dairy cows (n = 7) were compared to those of cows with subclinical (n = 7 ) using small RAN sequencing. Three hundred fifty-five miRNAs (341 known and 14 novel ones) were identified. There were 42 miRNAs up-regulated in serum-derived EVs from cows with subclinical mastitis, including bta-miR-1246, bta-miR-2431-3p, bta-miR-126-3p, bta-miR-29a, etc. The MAPK signaling pathway was the most affected pathway by clinical mastitis. Thus, miRNA alterations in mastitis serum-derived EVs support the potential regulator role of specific miRNAs as exosomal cargo in clinical mastitis physiology. Overall design: EVs of bovine serum were isolated from healthy cows (n = 7, the control group), and cows with subclinical mastitis (n = 7, the SM group), and cows with clinical mastitis (n = 7, the CM group) .