Proteomics and metabolomics reveal the role of miR-320b in regulating inflammation of bovine mammary epithelial cells.

MicroRNAs (miRNAs) are a class of endogenous non-coding small RNAs that are widely found in organisms and play an important regulatory role in various biological processes, especially immune and inflammatory responses. However, the function of miR-320b in the inflammatory responses of bovine mammary epithelial cells (bMECs) remains to be elucidated. In this study, we examined the miR-320b mimic transduction group (miR-320b_mimic) and negative control mimic transduction group (NC_mimic) of lipopolysaccharide-treated bMECs using data-independent acquisition (DIA) proteomics and untargeted metabolomics. Subsequently, we performed a joint analysis of the sequencing data. Proteomic analysis identified 330 differentially abundant proteins (DAPs) primarily related to PPAR, ferroptosis, arachidonic acid metabolism, IL-17, and complement and coagulation cascades. Metabolome analysis identified 128 and 66 differentially accumulated metabolites (DAMs) in the positive and negative ion mode primarily involved in linoleic acid metabolism, cholesterol metabolism, AMPK, MAPK, and chemokine. Integrated metabolomics and proteomics analysis revealed the co-enrichment of DAPs and DAMs in choline metabolism in cancer, endocrine resistance, glycerophospholipid metabolism, primary bile acid biosynthesis, and the ferroptosis signaling pathways. The results of quantitative real-time PCR (RT-qPCR) showed that compared with the NC_mimic group, mRNA expression levels of COX-2, IL-12 A, iNOS, MAPK1, and MAPK14 genes were significantly down-regulated, and the mRNA expression levels of PPARγ, CEBPα, CEBPβ, FABP4, and LPL genes were significantly up-regulated in the miR-320b_mimic group. These results provide crucial insights into the molecular regulatory functions of miR-320b and offer valuable data for further research on molecular breeding aimed at enhancing mastitis resistance in bovine animals.