Soybean-derived proteins and peptides enhance probiotic adhesion to intestinal cells by modulating mucin secretion and adhesion-related pathways

Abstract Dietary proteins influence the gut environment by modulating probiotic adhesion. This study investigated whether gastrointestinal-digested soybean protein isolate (dSPI) and peptides (dPEP1) enhance the adhesion of probiotics to intestinal LS174T cells. We found that 4 mg/mL dSPI and dPEP promoted the adhesion of Lacticaseibacillus rhamnosus GG (LGG) at 2 h and 4 h, and enhanced the adhesion of the weakly adherent strain Lacticaseibacillus plantarum K25 (K25) at 4 h and 6 h. This was associated with increased mucin secretion from LS174T cells. Transcriptomic analysis revealed that dSPI and dPEP regulated pathways related to cell adhesion molecules, inflammation, protein metabolism/transport, and glucose metabolism. Specifically, dSPI modulated all four pathways, whereas dPEP primarily targeted cell adhesion molecules by upregulating key genes to enhance adhesion. PCK1 and STAG3L3 were key genes regulating adhesion in dSPI and dPEP, respectively.