Epigenetic editing of the STAT5B promoter attenuates milk nutrient loss in a bovine mastitis cell model

Mastitis caused by Staphylococcus aureus infection impairs lactation and reduces milk nutritional quality in dairy cows, posing a major challenge for dairy production. However, current approaches to restore milk nutritional quality under mastitis-induced inflammatory conditions remain limited. Here, we investigated the potential of an epigenetic editing system to enhance lactation capacity in bovine mammary epithelial cells under mastitis conditions. We promoted cellular lactogenic differentiation in BMECs and MAC-T cells and quantified the lactation gene expression, revealing their upregulation during this process. The overexpression of lactation genes, achieved via both plasmid-based coding regions and promoter-targeted epigenetic editing, increased nutritional components in both cell lines, indicating a viable approach to improve milk quality through enhanced gene expression. Importantly, in a mastitis MAC-T cell model induced by Staphylococcus aureus infection, the epigenetic editing of the STAT5B promoter using dCas9-P300 effectively restored nutritional deficits, highlighting its potential as a therapeutic intervention for mastitis-associated nutritional impairment. Collectively, our results demonstrate that targeted epigenetic editing of lactation genes can reinstate lactogenic function and improve milk nutritional quality under pathological conditions, offering a promising strategy for the treatment of mastitis.