Transcriptional Insights into Anti-Adhesion of Human Milk Oligosaccharides Against E. coli O157:H7: Decoy Effects and Immunomodulatory

Human milk oligosaccharides (HMOs) exhibit potential in preventing enteric infections; however, the specific mechanisms by which HMOs act against Escherichia coli O157:H7 remain to be elucidated. This study investigated the anti-infective effects of HMOs using HT-29 cell models and transcriptomic analysis. Bacterial interaction assays showed that 10 mg/mL HMOs reduced E. coli adhesion by over 85%, primarily through molecular decoy activity (e.g., fimA, lpfD), targeting motility (e.g., qseC, fliC) and virulence (e.g., espL2, toxB) genes. Cellular interaction assays showed that HMO pretreatment of HT-29 cells reduced E. coli adhesion by over 80%, upregulated the expression of genes such as LAMA2 and COL4A3 to enhance barrier integrity, and increased the expression of immune-related genes like DRAM1 and CXCL8 to promote immune regulation. These findings suggest that HMOs act as multifunctional agents that disrupt pathogen adhesion and strengthen host defense mechanisms. Our results provide insights into the molecular mechanisms of HMOs and their potential applications in infant nutrition.