Defining compartmentalized stem and progenitor populations with distinct cell division frequency in the ocular surface epithelium

The study investigated stem and progenitor cell populations in the ocular surface epithelium, focusing on their division frequency and spatial distribution. Using EdU pulse-chase analysis and lineage tracing with three CreER transgenic mouse lines, researchers identified distinct stem cell dynamics in the cornea and conjunctiva. In the limbus, long-lived stem cells labeled with Slc1a3 CreER migrated toward the central cornea or expanded within the limbal region. In contrast, the central cornea contained mostly short-lived progenitor cells labeled by Dlx1 CreER and K14 CreER. The conjunctival epithelium was regenerated by distinct stem cell populations specific to each region. Severe corneal damage disrupted stem cell compartments, leading to conjunctivalization, while milder limbal injury increased laterally-expanding clones. This work provided tools for lineage tracing in the eye and defined multiple compartmentalized stem/progenitor populations and their responses to injury.