Differential Expression of miR-223-3p and miR-26-5p According to Different Stages of Mastitis in Dairy Cow

Mastitis is the disease that causes the greatest economic losses in dairy farming, significantly im-pairing animal welfare and the quality and quantity of milk produced. MicroRNAs are increasingly gaining attention, both in human and veterinary medicine, as biomarkers for various diseases. This study evaluated the diagnostic potential of four circulating microRNAs (miR-26-5p, miR-142-5p, miR-146a, and miR-223-3p) by examining changes in their expression in milk samples from dairy cows at different immune cells subpopulations correlated to different stage of mastitis in validated method. Additionally, the project has analysed the possible source of these circulating microRNA by the measurement of their secretion from activated immune cells (lymphocytes, monocytes, and neutrophils). miR-223-3p has been significantly expressed in acute stage of mastitis (p<0.01) but not in chronic or susceptible stages. mir-26-5p has been significantly reduced in acute, chronic and susceptible groups of animals. In immune cell cultures miR-26 has been shown to downregulate in LPS-stimulated neutrophils while miR-223 has been shown to be upregulated in PHA-stimulated lymphocytes. The differential expression of miR-223-3p and miR-26-5p together with differential and classic somatic cell count could be utilized for identifying the evolutionary stage of masti-tis-related inflammatory pathology.