Expression of the p53 family of proteins in central and peripheral human corneal endothelial cells.

PURPOSE

To determine the protein and mRNA expression of p53, p63, and p73 in central and peripheral human corneal endothelial cells. Since these proteins are known to be involved in the regulation of cell division, this study seeks information about their influence in regulating cell proliferation in the human corneal endothelium.

METHODS

Human donor corneas were separated into central and peripheral sections. The endothelial tissue from these samples was dissected and samples were analyzed for mRNA transcription of p53, transactivating p63 (TAp63), delta N p63 (DeltaNp63), transactivating p73 (TAp73), and delta N p73 (DeltaNp73) via the reverse transcriptase-polymerase chain reaction (RT-PCR). Additional samples were analyzed for p53, p63, and p73 protein expression via SDS-PAGE, western blotting, and immunodetection. Frozen corneal sections were immunostained for p53 and analyzed via fluorescence microscopy.

RESULTS

p53 and TAp63 mRNA and protein expression were detected in central and peripheral human corneal endothelium. p53 and TAp63 protein expression were greater in central than in peripheral tissue. DeltaNp63 and all isoforms of p73 were not detected in either central or peripheral corneal endothelium.

CONCLUSIONS

p53 is expressed in both peripheral and central human corneal endothelium, although it is more highly expressed in the central endothelium. Similarly, TAp63 is more highly expressed in central rather than in peripheral endothelium. This suggests that the peripheral endothelium may have more potential for cell division than the central endothelium. DeltaNp63, a stem cell marker, was not detected in the corneal endothelium. Neither the TAp73 nor the DeltaNp73 isoforms were detected in either central or peripheral human corneal endothelium.