Abstract
Purpose :
To investigate the function of Sox9 in corneal epithelial maintenance.
Methods :
Utilized CycB1-GFP reporter mice, which express GFP during S-G2-M stages of the cell cycle, and sorted for GFP+ cells from the corneal epithelium to enrich for stem and progenitor populations. Performed single-cell RNA sequencing on sorted cells and identified clusters of corneal, limbal, and conjunctival identity. Sox9 was identified as a differentially expressed gene in the limbal cluster compared to the corneal clusters. Performed lineage tracing experiments to validate SOX9 expression in vivo. Developed an inducible conditional Sox9 knockout model to validate SOX9 function in the corneal epithelium. Antibodies against Sox9, Keratin 14, Keratin 12, Loricrin, and Ki67 were used for immunofluorescence staining in tissue sections from control and conditional knockout eyes.
Results :
In the mouse cornea, SOX9 is expressed in the basal layers of the limbus and marks a population of limbal stem cells that give rise to long-lived corneal lineages. When Sox9 is conditionally ablated from the corneal epithelium in adult mice, corneal progenitor cells differentiate into hyperplastic, keratinized growths reminiscent of skin-like epidermis. These plaques are characterized by an expanded, hyperproliferative basal layer and the expression of epidermal-specific markers like Loricrin.
Conclusions :
Sox9 labels a population of limbal stem cells that contribute to the long-term maintenance of the corneal epithelium. Conditional ablation of Sox9 leads to corneal hyperplasia, keratinization, and transdifferentiation of corneal epithelium into epidermis.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.