Isoforms of p63 in corneal stem cells cultured on human amniotic membrane

The p63 gene supports stem cell proliferation and regulation in epithelial cells. In this study, corneal epithelial cells were cultured on human amniotic membrane (HAM) and investigated for p63 and its isoform genes. Human limbal biopsies obtained from cadaveric donor eyes were cultivated on intact and denuded HAM. Transactivation (TA) specific domain was positive in the limbal cells cultured over denuded HAM and negative on others. TAp63alpha,beta,gamma isoforms are negative in all the limbal cells cultured on intact, denuded and limbal tissues but not in cornel epithelial tissue. p63alpha isoform is present in all except on denuded HAM. Alphabeta sharing region is not expressed only in cornel epithelial tissue. Gamma isoform is expressed in all the samples. DeltaNp63alpha region is present in cells cultured over the intact HAM whereas it is negative on the cells cultured over the denuded HAM. The other isoforms such as DeltaNp63beta and DeltaNp63gamma are negative in all samples. The limbal cells cultured over the intact HAM were able to maintain high proliferative potential when compared to denuded HAM. Thus, p63 isoforms plays a biological function to retain the proliferative capacity of corneal epithelial cells and maintains the stemness when cultured on intact HAM.