Abstract
Purpose :
Inherited retinal ciliopathies are a genetically heterogeneous group of diseases with no effective cure available so far. Approximately 12% of pathogenic mutations found in patient screenings are nonsense mutations, resulting in premature stop codons (PTCs). Translational read-through inducing drugs (TRIDs) are suppressing PTCs depending on their genetic context, resulting in recovered protein expression. Designer aminoglycosides and the clinically approved Ataluren (PTC124, Translarna) are promising TRIDs. Here we study the susceptibility of different ciliopathy–causing nonsense mutations to translational read-through by miscellaneous TRIDs and compare the retinal toxicity of these compounds.
Methods :
To evaluate TRID mediated read-through, we generated constructs coding for nonsense mutations causing ciliopathies such as Usher syndrome, Bardet Biedl syndrome and Senior-Loken syndrome. We analyzed the recovery of protein expression after TRID application in HEK293T cells using quantitative immunofluorescence and Western blot analyses. Interaction assays were performed to validate protein function after translational read-through. We evaluated retinal toxicity of TRIDs by comparing TUNEL-assays of treated versus untreated mouse retina explants.
Results :
In cellular disease models we observed recovery of protein expression after TRID application in a dose-dependent manner for all ciliopathy-related nonsense mutations. The functionality of the recovered proteins was validated in interaction assays using known interaction partners. We showed improved biocompatibility for designer aminoglycosides and Ataluren, in comparison to canonical aminoglycosides like gentamicin.
Conclusions :
Taken together our data demonstrates excellent biocompatibility of TRIDs, along with substantial read-through efficacies for diverse ciliopathy-causing nonsense mutations. These results emphasize the feasibility of TRIDs as a therapeutic strategy tackling retinal ciliopathies caused by nonsense mutations.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.