PAD2 Deficiency Reveals Sex-Divergent Colonic Homeostasis, β-Catenin Remodeling, and Antibiotic-Sensitive Phenotypes.

PAD2 deficiency produced distinct colonic epithelial states in male and female mice before any injury.

• Global PAD2 knockout and wild-type littermate mice of both sexes were compared under basal conditions.
• Epithelial phenotypes were assessed by histology, immunofluorescence, immunoblotting, quantitative RT-PCR, and immunoprecipitation.
• The authors describe the findings as both sex-specific and sex-divergent colonic phenotypes.

Male PAD2 KO mice showed increased β-catenin phosphorylation and increased susceptibility to DSS colitis.

• Colitis was induced with dextran sodium sulfate in global PAD2 KO and WT littermates.
• The abstract reports increased β-catenin phosphorylation specifically in male KO mice.
• Male KO mice were more susceptible to DSS-induced injury than WT.

Female PAD2 KO mice showed increased total β-catenin abundance and preservation of structural epithelial features after DSS injury.

• This contrasts with the male KO phenotype of increased β-catenin phosphorylation and susceptibility.
• Structural epithelial features were assessed by histology and immunofluorescence following DSS injury.

Female KO mice had gut microbial community composition differing by genotype in an exploratory analysis.

• Microbial communities were evaluated by shotgun metagenomics.
• Genotype-associated differences were detected by exploratory Bray-Curtis PERMANOVA.
• The analysis is described as exploratory.

Broad-spectrum antibiotic treatment altered the female epithelial phenotype and reduced active β-catenin.

• Antibiotic treatment was used to probe antibiotic-sensitive factors related to β-catenin regulation and epithelial phenotypes.
• The female epithelial phenotype was changed by treatment, consistent with microbiota-sensitive contributions.

Antibiotic treatment progressively depleted luminal PAD2-immunoreactive proteins in feces.

• Fecal protein immunoblotting was used to detect PAD2-immunoreactive proteins.
• Depletion occurred progressively over the course of antibiotic treatment.
• This suggests that the luminal PAD2-immunoreactive material depends on antibiotic-sensitive sources such as the microbiota.

Exogenous recombinant human PAD2 increased epithelial protein citrullination and altered active β-catenin abundance in HT29 cells.

• Experiments were performed in vitro in HT29 colorectal epithelial cells.
• Recombinant human PAD2 exposure increased protein citrullination.
• Active β-catenin abundance was altered, linking PAD2 activity to β-catenin regulation.