Sexual Dimorphism Is Associated With Corneal Nerve and Epithelial Alterations and Tear-Film Defects in Pax6...

The purpose of this study was to determine how Pax6 haploinsufficiency alters epithelial maturation, immune balance, sensory innervation, and lacrimal function across the ocular surface, and how these defects affect corneal repair.

Pax6tm1Ued mice crossed with CMV-Cre were used to generate Pax6+/- animals. Ocular-surface maturation, epithelial organization, immune infiltration, and sensory innervation were assessed by whole-cornea immunostaining. Standardized corneal abrasion was used to evaluate epithelial and neural repair. Corneal RNA sequencing and tear-film proteomics were performed in both sexes to define genotype- and sex-dependent molecular programs.

Pax6+/- mice showed heterogeneous ocular phenotypes, delayed eyelid opening, reduced KRT12, persistent central KRT14 expansion, and a sustained deficit in central proliferation. Immune infiltration was elevated from eyelid opening onward. Corneal nerves were markedly reduced and disorganized, with decreased sensitivity despite minimal trigeminal transcriptional changes. Transcriptomics revealed sex-specific gene-expression patterns converging on inflammation and extracellular-matrix remodeling. After abrasion, closure rates were preserved, but Pax6+/- corneas failed to fully restore normal epithelial identity, territorial patterning, or nerve density. Tear secretion was impaired in a sex-dependent manner, and proteomics showed depletion of structural and antioxidant proteins with exaggerated inflammatory and keratinization responses after injury.

Our model showed that Pax6 haploinsufficiency is associated with epithelial dysmaturation, chronic inflammation, denervation, defective repair, and sex-modulated lacrimal dysfunction. These integrated abnormalities mirror key features of AAK and underline inflammation, neurotrophic support, and tear-film quality as therapeutic targets.