Abstract
Purpose: :
The nuclear receptors family contains numerous protein members able to regulate the expression of a wide number of genes in several human tissues. A time and space regulation of theirs expressions throughout life is essential to control precisely the different physiological or metabolic cellular cascades. Belonging to this family, six different nuclear receptors are essential for the vitamin A signalling transduction. Among these, we decide to focus our work on both RAR and RXR β isoforms in order to demonstrate their age-dependant expression on cornea.
Methods: :
Cornea sections from 11 day old children and donors from 2, 6, 16, 25, 40, 51, 69, and 83 years (y) old were fixed. The RAR and RXRβ were detected using primary specific IgG rabbit antibody against both proteins. Negative controls were done for all stages on serial slides by using normal rabbit IgG as primary antibody instead of both previous one. Then, a secondary antibody Cyanin3-coupled against rabbit IgG was used. Finally, the nuclei were visualized by DAPI staining.
Results: :
Both corneal endothelium and epithelium showed an important nuclear staining corresponding to the expression of RARβ and RXRβ proteins. Our results demonstrate furthermore, that the expression of both proteins is conserved during all lifelong.
Conclusions: :
This work clearly demonstrates that the expression pattern of both RARβ and RXRβ is not restricted to only one part of the cornea. In fact, endothelium and epithelium clearly express these isoforms. Furthermore, our data confirmed that cellular corneal functions could be supported, by the vitamin A nuclear pathways as the expression of two of the principal actors is conserved for all life period tested.
Keywords: cornea: basic science • transcription factors