Abstract
Purpose: :
To achieve its harmonious functions, the eye structure has an absolute requirement for the nuclear receptors. We have already demonstrated the implications of retinoic acid receptors (RARs) and retinoid X receptors (RXRs) in this structure. The RXRs were found to be expressed in various parts of the eye and are well-known partners of other family members called liver X receptors (LXRα and LXRβ). LXR deficient mice helped to elucidate the role of LXRs in various tissues. So far, no role for these receptors has been assigned in eye. In order to elucidate this question, the first part of this work was to define the precise expression pattern of LXRα and β gene in mouse and human eye and in a second time to link a mouse eye phenotype as a direct consequence of the inactivation of mouse LXRα or β as already described for RXRα deficient mice.
Methods: :
Total mRNA was extracted from total mouse eyes (wild type and mutant) and from conjunctiva, cornea and lens (capsule) of mouse (wild type and mutant) and human samples. These mRNA were submitted to RT-PCR experiments using specific primers for LXRα and LXRβ. Furthermore, precise morphological and histological analysis of eyes obtained from LXR null mice was done.
Results: :
We first confirm the expression of α and β RXRs in mouse eyes (wild type or mutant) and in human eye samples. In a second time, the use of specific primers for mouse LXRα and β permit us to show that these two nuclear factors are expressed in total mouse eyes as in the three different part of eye tested (cornea, conjunctiva and lens). Same results for human LXRα and β were obtained in human eye samples. Finally, the precise morphological and histological analysis of the mouse wild type and mutant eyes (LXRα and β -/-) lets appear an abnormal structure layout.
Conclusions: :
LXRα and β were present in the mouse and human eyes. The functional regulatory heterodimer RXR/LXR could be functional in mouse and human eyes and our preliminary data leads us to think that, as in RXR-/- mouse eye, LXR is another fundamental nuclear factor to maintain both integrity and eye functions.
Keywords: gene/expression