N 6 -Methyladenosine Modification Profile in Bovine Mammary Epithelial Cells Treated with Heat-Inactivated Staphylococcus aureus .

The symptoms of mastitis caused by Staphylococcus aureus ( S. aureus ) in dairy cows are not obvious and difficult to identify, resulting in major economic losses. N 6 -Methyladenosine (m 6 A) modification has been reported to be closely associated with the occurrence of many diseases. However, only a few reports have described the role of m 6 A modification in S. aureus -induced mastitis. In this study, after 24 h of treatment with inactivated S. aureus , MAC-T cells (an immortalized bovine mammary epithelial cell line) showed increased expression levels of the inflammatory factors IL-1 β , IL-6, TNF- α , and reactive oxygen species. We found that the mRNA levels of METLL3, METLL14, WTAP, and ALKBH5 were also upregulated. Methylated RNA immunoprecipitation sequencing analysis revealed that 133 genes were m 6 A hypermethylated, and 711 genes were m 6 A hypomethylated. Biological functional analysis revealed that the differential m 6 A methylated genes were mainly related to oxidative stress, lipid metabolism, inflammatory response, and so on. In the present study, we also identified 62 genes with significant changes in m 6 A modification and mRNA expression levels. These findings elucidated the m 6 A modification spectrum induced by S. aureus in MAC-T cells and provide the basis for subsequent m 6 A research on mastitis.