Effects of Selenium on MAC-T Cells in Bovine Mastitis: Transcriptome Analysis of Exosomal mRNA Interactions

Selenium, a micronutrient, is indispensable for maintaining normal metabolic functions in animals and plants. Selenium has shown promise in terms of its effect on the immune function, ability to control inflammation, and ability to improve bovine mammary gland health. Bovine mastitis remains a major threat to dairy herds globally and has economically significant impacts. The exosomes are a new mode of intercellular communication. Exosomal transfer of mRNAs, microRNAs, and proteins between cells affects the protein production of recipient cells. The development of novel high-throughput omics approaches and bioinformatics tools will help us understand the effects of selenium on immunobiology. However, the differential expression of mRNAs in bovine mammary epithelial cell-derived exosomes has rarely been studied. In the present study, differences in the exosomal transcriptome between control and selenium-treated MAC-T cells were identified by RNA sequencing and transcriptome analysis. The results of mRNA profiling revealed 1978 genes in exosomes that were differentially expressed between the selenium-treated and control cells. We selected and analyzed 91 genes that are involved in inflammation, redox reactions, and immune cell function related to mastitis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed enrichment pathways involved in selenoproteins and the Ras/PI3K/AKT, MAPK, and FOXO signaling pathways. Our results revealed that selenium may play a crucial role in immune and inflammatory regulation by influencing the differential expression of exosomal mRNAs of key genes in bovine mastitis.