Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model.
Carolina UggentiKit BriantAnne-Kathrin StreitSteven ThomsonYee Hui KoayRichard A BainesEileithyia SwantonForbes D MansonPublished in: Disease models & mechanisms (2016)
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.
Keyphrases
- wild type
- induced apoptosis
- poor prognosis
- cell cycle arrest
- binding protein
- intellectual disability
- magnetic resonance
- stem cells
- single cell
- emergency department
- magnetic resonance imaging
- cell death
- endoplasmic reticulum stress
- computed tomography
- multiple myeloma
- combination therapy
- long non coding rna
- newly diagnosed
- small molecule