Objective

Malnutrition affects 148 million children under five worldwide and remains a major public health concern. Protein deficiency participates to stunted growth, metabolic disorders, delayed microbiome maturation, and intestinal remodeling. The sex-specific susceptibility, where boys are more severely affected than girls, complicates the understanding and care of children suffering from protein malnutrition. The objective of this study is to investigate how protein malnutrition shapes the intestinal epithelium during postnatal development, with a focus on diet–host interactions and sex-specific adaptations.

Methods

Juvenile mice of both sexes were fed either a control (20% protein) or an isocaloric low-protein (5%) diet during five weeks post-weaning. To investigate both the structural and transcriptional adaptations of the intestinal epithelium, we used both histological analysis and single-cell RNA sequencing of the intestinal epithelium at 28 and 56 postnatal days (that is, one and five weeks post-weaning).

Results

Histological analysis revealed that 5 weeks of protein malnutrition led to decreased crypt depth in both males and females, without villus blunting. Remarkably, we observed a female-specific increase in goblet cell numbers. These findings suggest that the juvenile intestinal epithelium undergoes structural and compositional remodeling in response to chronic protein deficiency. To better understand acute responses of this tissue, we generated and started to analyze scRNA-seq data after 1 week of protein restriction. Preliminary scRNA-seq analysis suggests that protein malnutrition induces shifts in epithelial composition and gene expression, with distinct male and female responses. Notably, common and distinct patterns emerge between males and females in response to the same dietary challenge, suggesting a sexually dimorphic response of the intestinal epithelium.

Conclusion

Our study uncovers diet- and sex-specific epithelial adaptations to protein malnutrition in juvenile mice. The integration of histology and scRNA-seq provides insights into epithelial remodeling and cell type-specific responses to dietary stress. This work contributes to a better understanding of how the gut integrates luminal signals. It highlights sex as an important variable in the response to early-life malnutrition, providing information that could guide future interventions targeting the gut–microbiome–host axis.