β-Catenin Inactivation Is a Pre-Requisite for Chick Retina Regeneration

The study investigated the role of β-catenin in chick retina regeneration, revealing that its inactivation was necessary for regeneration to occur. In the chick eye, retina regeneration could happen through stem/progenitor cells in the ciliary margin (CM) or transdifferentiation of the retinal pigmented epithelium (RPE), both requiring fibroblast growth factor 2 (FGF2). The researchers found that nuclear β-catenin was transiently lost in the CM after injury, and its continued absence was linked to the presence of FGF2. In the RPE, nuclear β-catenin prevented cells from entering the cell cycle, but its loss, facilitated by FGF2, allowed dedifferentiation and proliferation. Additionally, disrupting β-catenin signaling induced regeneration from both the CM and RPE without FGF2. The findings suggested that β-catenin inactivation was crucial for enabling cell cycle entry and regeneration in the chick retina.