Translational read-through of the RP2 Arg120stop mutation in patient iPSC-derived retinal pigment epithelium cells.

TitleTranslational read-through of the RP2 Arg120stop mutation in patient iPSC-derived retinal pigment epithelium cells.
Publication TypeJournal Article
Year of Publication2015
AuthorsSchwarz N, Carr A-J, Lane A, Moeller F, Chen LLi, Aguilà M, Nommiste B, Muthiah MN, Kanuga N, Wolfrum U, Nagel-Wolfrum K, da Cruz L, Coffey PJ, Cheetham ME, Hardcastle AJ
JournalHum Mol Genet
Volume24
Issue4
Pagination972-86
Date Published2015 Feb 15
ISSN1460-2083
KeywordsCell Differentiation, Cellular Reprogramming, Cilia, Epithelial Cells, Eye Proteins, Fibroblasts, Gene Expression, Humans, Induced Pluripotent Stem Cells, Intracellular Signaling Peptides and Proteins, Male, Membrane Proteins, Mutation, Oxadiazoles, Phenotype, Protein Biosynthesis, Protein Transport, Retinal Pigment Epithelium, Young Adult
Abstract

Mutations in the RP2 gene lead to a severe form of X-linked retinitis pigmentosa. RP2 patients frequently present with nonsense mutations and no treatments are currently available to restore RP2 function. In this study, we reprogrammed fibroblasts from an RP2 patient carrying the nonsense mutation c.519C>T (p.R120X) into induced pluripotent stem cells (iPSC), and differentiated these cells into retinal pigment epithelial cells (RPE) to study the mechanisms of disease and test potential therapies. RP2 protein was undetectable in the RP2 R120X patient cells, suggesting a disease mechanism caused by complete lack of RP2 protein. The RP2 patient fibroblasts and iPSC-derived RPE cells showed phenotypic defects in IFT20 localization, Golgi cohesion and Gβ1 trafficking. These phenotypes were corrected by over-expressing GFP-tagged RP2. Using the translational read-through inducing drugs (TRIDs) G418 and PTC124 (Ataluren), we were able to restore up to 20% of endogenous, full-length RP2 protein in R120X cells. This level of restored RP2 was sufficient to reverse the cellular phenotypic defects observed in both the R120X patient fibroblasts and iPSC-RPE cells. This is the first proof-of-concept study to demonstrate successful read-through and restoration of RP2 function for the R120X nonsense mutation. The ability of the restored RP2 protein level to reverse the observed cellular phenotypes in cells lacking RP2 indicates that translational read-through could be clinically beneficial for patients.

DOI10.1093/hmg/ddu509
Alternate JournalHum. Mol. Genet.
PubMed ID25292197