Lithium increases p63 levels in cultured human limbal epithelial stem cells

Abstract

AbstractPurpose p63 (isoform ΔNp63α) is a putative stemness marker for limbal epithelial stem cells (LESCs), and is essential for the proliferative potential of stem cells in stratified epithelia. The niche for LESCs is the limbus, located between the clear cornea and bulbar conjunctiva. LESCs are responsible for and able to renew and repair the corneal epithelium throughout life. In a number of disorders and after trauma, limbal stem cell deficiency (LSCD) may occur, and this can be treated by isolation and cultivation of LESCs from a healthy eye followed by transplantation to the affected eye. It is known that the percentage of p63‐bright cells affect the success rate of the transplantation. Thus, we wanted to reveal whether lithium, a known Wnt signaling inducing agent, may increase the expression of p63 in human LESC cultures.Methods Small limbal biopsies (1x1‐2mm) were dissected from donor corneas and cultured in a standard medium at 37 oC and 5% CO2 under different concentrations of lithium (LiCl2). The cells were cultured for 3‐6 weeks and medium was changed every 2‐3 days.Results The epithelial cells migrated from the limbal biopsy to form an epithelial sheet. Lithium enhanced the expression of p63 compared to controls, and this was confirmed by qRTPCR. Further studies mapping epigenetic alterations of the lithium treatment are currently conducted.Conclusion Lithium induced upregulation of p63 in LESC could be clinically important by increasing the long term success of limbal stem cell therapy.