Abstract
Autosomal recessive bestrophinopathy (ARB) is a retinopathy caused by mutations in the bestrophin-1 protein, which is thought to function as a Ca2+-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.
Original language | English |
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Pages (from-to) | 1317-1328 |
Number of pages | 12 |
Journal | Disease Models and Mechanisms |
Volume | 9 |
Issue number | 11 |
Early online date | 2 Nov 2016 |
DOIs | |
Publication status | E-pub ahead of print - 2 Nov 2016 |
Keywords
- Animals
- Bestrophins/genetics
- Biotinylation
- Cell Polarity/drug effects
- Dogs
- Endoplasmic Reticulum/drug effects
- Epithelial Cells/drug effects
- Eye Diseases, Hereditary/genetics
- HEK293 Cells
- Humans
- Madin Darby Canine Kidney Cells
- Models, Biological
- Mutant Proteins/metabolism
- Mutation/genetics
- Patch-Clamp Techniques
- Phenylbutyrates/pharmacology
- Protein Transport/drug effects
- Retinal Diseases/genetics
- Small Molecule Libraries/pharmacology
- Transfection