Purchase this article with an account.
Francois Paquet-Durand, Ayse Sahaboglu, Dragana Trifunovic, Kangwei Jiao, Bernd Wissinger, Marius Ueffing; Retinitis Pigmentosa: Excessive cGMP signalling in Pde6a and Pde6b mouse mutants drives retinal degeneration. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1700.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Retinitis Pigmentosa (RP) is a group of hereditary retinal diseases, characterized by mutation-induced rod photoreceptor degeneration. Until today, no adequate treatment is available and the photoreceptor cell death mechanisms remain poorly understood. In various animal models for RP, an accumulation of cGMP has been shown already, in particular, in animals that carry mutations in the cGMP hydrolyzing enzyme PDE6. However, it is still unclear to what extent different PDE6 mutations cause cGMP accumulation and how this correlates with progression speed and severity of retinal degeneration.
We used three different Pde6a (V685M, R562W, D670G) and two different Pde6b (rd1, rd10) mouse mutants to study and compare the effects of different types of genetic mutations. We used immunofluorescence to study cGMP accumulation, as well as the TUNEL assay, and histology to assess photoreceptor cell death and survival, respectively. For these parameters a time-series was collected to establish links between mutation types and severity of retinal degeneration.
The analysis of cell death markers in the different mutants showed degeneration onsets ranging from PN10 in Pde6a V685M mice to PN24 in Pde6a D670G animals. The Pde6a D670G mutant also showed the slowest overall progression of retinal degeneration and thus the mildest phenotype. Remarkably, analogous mutations in the Pde6a R562W mutant and the Pde6b rd10 (R560C) mutant led to very similar degeneration phenotypes, confirming the equivalent importance of both genes for photoreceptor viability.
There is a large genetic diversity in the mutations causing RP and even when affecting the same gene, different mutations may cause very different degeneration phenotypes. Our study may serve to predict time-courses of retinal degeneration in human RP patients and help to define the optimal time-points for clinical interventions. In addition, future modelling approaches may make use of these datasets to provide better predictions on the potential pathogenicity of new mutations in PDE6A or PDE6B.
This PDF is available to Subscribers Only