Purchase this article with an account.
Minghao Jin, Songhua Li, Kota Sato, Michael Sendtner; Hyper Phototransduction of Cone and Rod Photoreceptors in Cntf-/- Mice is Underpinned by Upregulated Opsins and RPE65. Invest. Ophthalmol. Vis. Sci. 2014;55(13):3473.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Ciliary Neurotrophic Factor (CNTF) is a potent neurosurvival factor and has been applied to clinical trials for curing retinal degenerative diseases. CNTF exerts its function mainly through the gp130-STAT3 pathway that regulates gene expression. However, the role of CNTF in regulation of genes involved in the phototransduction and the visual cycle remains poorly understood. The purpose of this study is to define the role of CNTF in vision by identifying key phototransduction and visual cycle genes altered in Cntf-/- mice.
We generated Cntf-/- mice with homologous Leu450 alleles of the Rpe65 gene. Visual function of cone and rod photoreceptors in 129S2/Sv and Cntf-/- mice was analyzed by photopic and scotopic electroretinography (ERG). The dark-adaptation kinetics in these mice was evaluated by recording scotopic ERG responses under different dark-adaptation conditions. We measured the flow of retinoids in the retinas and RPE to compare the regeneration rates of the 11-cis retinal chromophore in 129S2/Sv and Cntf-/-retinas. Expression levels of photoreceptor specific proteins and the visual cycle enzymes were determined by quantitative immunoblot analysis. Retinoid isomerase activity in the RPE was measured by monitoring synthesis of 11-cis retinol from all-trans retinol substrate. Retinoids were analyzed by high-performance liquid chromatography.
Cone and rod ERG responses in overnight dark-adapted Cntf-/- mice were significantly higher than those in 129S2/Sv mice under the same light condition. The recovery kinetics of rod photoreceptor light sensitivity measured by scotopic ERG was faster in the Cntf-/- mice compared to that in the wild-type (WT, 129S2/Sv) mice. Consistent with this result, the regeneration rate of the visual chromophore in the Cntf-/- retina was faster than that in WT mice. The outer nuclear layers stained with DAPI were at least 20% thicker in Cntf-/- mice than those in WT mice. Expression levels of cone opsins, rod opsin, and RPE65 in Cntf-/- mice at p10 and/or p21 were significantly higher than those in WT mice at the same ages. The retinoid isomerase activity in the Cntf-/- RPE was at least 15% higher than that in WT RPE.
CNTF negatively regulates expression of cone opsin, rod opsin, and Rpe65, which play a pivotal role in photoreceptor light perception and degeneration of photoreceptors induced by light damage.
This PDF is available to Subscribers Only