Self-organized centripetal movement of corneal epithelium in the absence of external cues

Maintaining the structure of the cornea is essential for high-quality vision. In adult mammals, corneal epithelial cells emanate from stem cells in the limbus, driven by an unknown mechanism towards the centre of the cornea as cohesive clonal groups. Here we use complementary mathematical and biological models to show that corneal epithelial cells can self-organize into a cohesive, centripetal growth pattern in the absence of external physiological cues. Three conditions are required: a circumferential location of stem cells, a limited number of cell divisions and mobility in response to population pressure. We have used these complementary models to provide explanations for the increased rate of centripetal migration caused by wounding and the potential for stem cell leakage to account for stable transplants derived from central corneal tissue, despite the predominantly limbal location of stem cells. The cornea is formed of cells that originate from the outer circle of stem cells and that move towards its centre. Here, the authors show that the movement pattern is self-organised, requiring no cues, and that stem cell leakage may account for the presence of stem cells at the centre of the cornea.