Transcriptome Profiling of m6A mRNA Modification in Bovine Mammary Epithelial Cells Treated with Escherichia coli

Mastitis is a common disease in dairy cows that is mostly caused by E. coli, and it brings massive losses to the dairy industry. N-6-Methyladenosine (m(6)A), a methylation at the N-6 position of RNA adenine, is a type of modification strongly associated with many diseases. However, the role of m(6)A in mastitis has not been investigated. In this study, we used MeRIP-seq to sequence the RNA of bovine mammary epithelial cells treated with inactivated E. coli for 24 h. In this in vitro infection model, there were 16,691 m(6)A peaks within 7066 mRNA transcripts in the Con group and 10,029 peaks within 4891 transcripts in the E. coli group. Compared with the Con group, 474 mRNAs were hypermethylated and 2101 mRNAs were hypomethylated in the E. coli group. Biological function analyses revealed differential m(6)A-modified genes mainly enriched in the MAPK, NF-kappa B, and TGF-beta signaling pathways. In order to explore the relationship between m(6)A and mRNA expression, combined MeRIP-seq and mRNA-seq analyses revealed 212 genes with concomitant changes in the mRNA expression and m(6)A modification. This study is the first to present a map of RNA m(6)A modification in mastitis treated with E. coli, providing a basis for future research.