- SCOPE: Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency and currently the leading cause of mortality in preterm infants. Recent studies show that human milk oligosaccharides (HMOs) reduce the frequency and incidence of NEC; however, the molecular mechanisms for their protection are largely unexplored. METHODS AND RESULTS: To address this gap, a genome-wide profiling of the intestinal epithelial transcriptome in response to HMOs using RNA-sequencing is performed. It is found that HMOs alter the host transcriptome in 225 unique target genes pertaining to cell proliferation and differentiation, including upregulation of stem cell differentiation marker HMGCS2. To validate these results, differentiation in Caco-2Bbe1 (Caco-2) intestinal cells is verified by Alcian Blue staining and transepithelial electrical resistance (TER) recordings. Furthermore, an in vivo model of NEC is also employed whereby neonatal pups are gavage fed HMOs. Interestingly, HMOs-fed pups show enhanced cell MUC2 differentiation and HMGCS2 expression. CONCLUSIONS: These findings demonstrate HMOs protect against NEC in part by altering the differentiation of the crypt-villus axis. In addition, this study suggests that pooled HMOs directly induce a series of biological processes, which provide mechanistic insights to how HMOs protect the host intestine.