Single-cell transcriptome analysis reveals the association between ketone body synthesis and morphogenic profile of intestinal epithelia in neonatal mice

The intestinal epithelium undergoes robust maturation postnatally, yet its early-life characteristics remain poorly understood. Using single-cell RNA sequencing, we analyzed intestinal epithelial cells from neonatal (10-day-old) and juvenile (21-day-old) mice reared under both specific pathogen-free and germ-free conditions. Among the various cell types comprising the intestinal epithelia, we found that enterocytes, in particular, exhibit markedly different features between these stages. Enterocytes of neonatal mice show reduced expression of secretory host defense-related genes independently of microbial colonization. These genes are upregulated in juvenile enterocytes in a microbiota-dependent manner. Conversely, neonatal enterocytes display upregulation of ketogenesis-related genes, which correlates with high expression of genes contributing to cell morphogenesis rather than serving primarily as an energy source. These findings provide novel insights into early-life maturation of intestinal epithelia offering implications for understanding neonatal intestinal pathologies. Overall design: Small intestinal epithelial cells of neonatal and juvenile mice were isolated by flowcytometry and analyzed using single cell RNA-sequencing.