EM Dipeptide Enhances Milk Protein Secretion: Evidence from Integrated Metabolomic and Transcriptomic Analysis

<b>Background/Objectives:</b> Breast milk provides essential nutrition and immune protection to support infant growth and development. However, insufficient breast milk remains a serious issue, and bioactive peptides represent a potential strategy to promote lactation. In this study, we investigated the impact of a methionine-containing dipeptide, EM, on MCF-10A mammary epithelial cells. <b>Methods:</b> MCF-10A cells were treated with EM, and cell proliferation and the expression of key milk protein genes were assessed. Integrated transcriptomic and untargeted metabolomic analyses were performed to identify EM-induced changes in metabolic and gene expression pathways. <b>Results:</b> EM treatment significantly enhanced cell proliferation and upregulated the expression of key milk protein genes (CSN1S1 (casein alpha-S1, encoding alpha-S1 casein), CSN2 (casein beta, encoding beta-casein), and CSN3 (casein kappa, encoding kappa-casein)) at both transcriptional and protein levels compared to controls. Integrated transcriptomic and metabolomic analyses revealed that EM reprogrammed amino acid metabolism, lipid biosynthesis, and nutrient transport pathways. Core genes such as SLC7A11, APOE, and ABCA1 were identified as critical nodes linking metabolic and transcriptional networks. <b>Conclusions:</b> These findings indicate that EM may promote lactogenic activity by modulating metabolic and transcriptional networks <i>in vitro</i>, highlighting the potential of dipeptide-based nutritional interventions, which warrants further <i>in vivo</i> validation.