Molecular Mechanisms of Peptide–Calcium Complexes in Enhancing Calcium Absorption: A Transcriptome Analysis of Caco-2 Cells Treated with Whey Protein-Derived Peptides DAF and EAC

Calcium-binding peptides have been shown to enhance calcium absorption, but the mechanism of their action is unclear. In this study, we investigated the effects of two whey protein-derived calcium-binding peptides, DAF and EAC, on calcium absorption and gene expression in Caco-2 cells. Our findings demonstrated that both peptides enhanced calcium absorption in a time-specific and peptide-specific manner and that PEPT1, the main peptide transporter in the intestine, was not involved in this process. Transcriptome analysis revealed that the calcium-binding peptides modulated the expression of genes related to various biological processes and pathways, such as cell signaling, protein transport, hormone regulation, oxidoreductase activity, and inflammatory responses, some of which were related to the TRPV6 pathway. Furthermore, DAF and EAC appeared to influence distinct cellular processes, with DAF potentially impacting gene expression and chromatin structure, while EAC may play a role in cell division and differentiation. Both peptides were found to activate the MAPK signaling pathway, which is closely linked to calcium ion absorption. These findings elucidate the molecular mechanisms, underlying the promotion of calcium absorption by peptide–calcium complexes, and suggest the potential applications of calcium-binding peptides as functional food ingredients with enhanced bioavailability and efficacy.