Purchase this article with an account.
Paul A Nakamura, Shibing Tang, Sheng Ding, Thomas A Reh; Manipulating photoreceptor gene expression with putative Nr2e3 modulators. Invest. Ophthalmol. Vis. Sci. 2016;57(12):580.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Mutations in photoreceptor-specific genes, such as rhodopsin, are a common cause of retinal degenerative diseases like retinitis pigmentosa (RP). In RP, rod photoreceptors are primarily affected, but death of rods then leads to a secondary, non-cell autonomous death of cone photoreceptors. Chemical probes targeted against Nr2e3, a rod-specific orphan nuclear receptor that regulates photoreceptor gene expression, may be therapeutically useful for preventing photoreceptor cell death in diseases like RP.
We used intact retinal explant cultures from postnatal day 0 (P0) and P12 C57Bl6 mice to screen 10 putative agonists and inverse agonists of Nr2e3 previously identified in either a reporter screen with CHO cells or a cell-free time-resolved fluorescence energy-transfer (TR-FRET) assay. After a 2-3 day culture period, we collected the retinas and assayed rhodopsin expression by qPCR. We further characterized the effects of one modulator, CA88, in vitro and in vivo. Finally, we tested if CA88 could prevent degeneration in vitro in a mouse model of RP.
In P0 explant cultures, CA88 decreased the expression of the rod specific genes Nrl, Nr2e3, Rho, and Gnat1 compared to DMSO treatment by qPCR analysis. Additionally, P0 retinas cultured with CA88 expressed less rhodopsin protein than DMSO controls as assessed by Western blot analysis and immunofluorescent labeling in sections. CA88 treatment increased the expression of Thrb, which is expressed in developing cones, and S opsin immunoreactvity in sectioned explants. In P12 explant cultures, CA88 decreased the expression of Nrl, Nr2e3, Rho, Gnat1 and Pde6b. Furthermore, CA88 dramatically decreased rhodopsin staining, but increased the number of S opsin-positive cells in the ONL. In vivo, we found that CA88 decreased Rho expression and increased the number of S opsin-positive photoreceptors in perinatal mice. Intraocular injection of CA88 decreased rhodopsin expression in adult mice. Finally, we found that explants from RhoP23H mice treated with CA88 had thicker ONLs than DMSO treated explants.
Nr2e3 modulator CA88 affected the expression of several photoreceptor genes in vitro and in vivo, and may be useful for the treatment of degenerative diseases like RP.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only