1. Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model.
- Author
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Uggenti C, Briant K, Streit AK, Thomson S, Koay YH, Baines RA, Swanton E, and Manson FD
- Subjects
- Animals, Biotinylation, Dogs, Endoplasmic Reticulum drug effects, Endoplasmic Reticulum metabolism, Epithelial Cells drug effects, Eye Diseases, Hereditary genetics, Eye Diseases, Hereditary pathology, HEK293 Cells, Humans, Madin Darby Canine Kidney Cells, Models, Biological, Mutation genetics, Patch-Clamp Techniques, Phenylbutyrates pharmacology, Protein Transport drug effects, Retinal Diseases genetics, Retinal Diseases pathology, Small Molecule Libraries pharmacology, Transfection, Bestrophins genetics, Bestrophins metabolism, Cell Polarity drug effects, Epithelial Cells metabolism, Epithelial Cells pathology, Mutant Proteins metabolism
- Abstract
Autosomal recessive bestrophinopathy (ARB) is a retinopathy caused by mutations in the bestrophin-1 protein, which is thought to function as a Ca
2+ -gated Cl- channel in the basolateral surface of the retinal pigment epithelium (RPE). Using a stably transfected polarised epithelial cell model, we show that four ARB mutant bestrophin-1 proteins were mislocalised and subjected to proteasomal degradation. In contrast to the wild-type bestrophin-1, each of the four mutant proteins also failed to conduct Cl- ions in transiently transfected cells as determined by whole-cell patch clamp. We demonstrate that a combination of two clinically approved drugs, bortezomib and 4-phenylbutyrate (4PBA), successfully restored the expression and localisation of all four ARB mutant bestrophin-1 proteins. Importantly, the Cl- conductance function of each of the mutant bestrophin-1 proteins was fully restored to that of wild-type bestrophin-1 by treatment of cells with 4PBA alone. The functional rescue achieved with 4PBA is significant because it suggests that this drug, which is already approved for long-term use in infants and adults, might represent a promising therapy for the treatment of ARB and other bestrophinopathies resulting from missense mutations in BEST1., Competing Interests: The authors declare no competing or financial interests., (© 2016. Published by The Company of Biologists Ltd.)- Published
- 2016
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