Abstract
Purpose:
Previously in our lab we detected photoreceptor degeneration in Chx10-Cre-Ezh2flox/flox mice, suggesting that histone methylase Ezh2 plays an essential role in the retinal photoreceptor development and function. In this study, we sought to investigate the role of Ezh2 in retinal ganglion cell (RGC) development and function.
Methods:
To analyze the role of Ezh2 in RGC development, we generated RGC specific deficiency of Ezh2 by crossing Math5-cre with Ezh2flox/floxt mice. Retinal functions were assessed by electroretinography (ERG) in animals aged 1- 8 months. The thickness of the ganglion cell complex (GCC) was measured with spectrum domain-OCT. RGCs and optic nerve fibers were counted in anti-βIII-tubulin immunolabeled retinal flat-mounts and optic nerve cross sections, respectively. The expression levels of various retinal cell markers, such as photoreceptor (recoverin) and ganglion cell (β-III-tubulin) markers were quantitatively assessed by both immunolabeling and real time RT-PCR. cDNA microarray was performed to determine the gene expression profile in Ezh2-deficient mice. In addition, purified RGC were cultured and their cell survival and neurite outgrowth were determined. In the above studies, Ezh2flox/flox mice were used as control animals.
Results:
Math5Cre-Ezh2flox/flox mice showed no significant difference in ERG a wave and b wave responses and GCC thickness. The retinal lamination and staining pattern of recoverin+ and β-III-tubulin+ cells were visibly comparable between the knockout and control mice. Moreover, we did not observe significant differences in wildtype and Math5-Ezh2-/- mice in RGC survival and neurite outgrowth ability in culture.Results of the cDNA microarray showed that 0.3% of genes were upregulated and 0.05% of genes were downregulated in RGCs.
Conclusions:
No apparent developmental or functional defects were observed in Math5Cre-Ezh2-/- mice, suggesting that Ezh2 may not play a significant role in RGC development or function.
Keywords: 698 retinal development •
531 ganglion cells •
533 gene/expression