title: Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model.
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.
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Carolina
authors: 0000-0003-2673-5120
authors: C
authors: Uggenti
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Kit
authors: K
authors: Briant
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Anne-Kathrin
authors: AK
authors: Streit
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Steven
authors: S
authors: Thomson
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Yee Hui
authors: YH
authors: Koay
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK.
authors: Richard A
authors: 0000-0001-8571-4376
authors: RA
authors: Baines
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK lisa.swanton@manchester.ac.uk forbes.manson@manchester.ac.uk.
authors: Eileithyia
authors: 0000-0002-3299-4228
authors: E
authors: Swanton
authors: Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK lisa.swanton@manchester.ac.uk forbes.manson@manchester.ac.uk.
authors: Forbes D
authors: 0000-0002-8342-660X
authors: FD
authors: Manson
mesh_terms: D000818:Animals; D000075002:Bestrophins / Q000235:genetics* / Q000378:metabolism*; D019921:Biotinylation; D016764:Cell Polarity / Q000187:drug effects; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D015785:Eye Diseases, Hereditary / Q000235:genetics / Q000473:pathology; D057809:HEK293 Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D018408:Patch-Clamp Techniques; D010654:Phenylbutyrates / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D012164:Retinal Diseases / Q000235:genetics / Q000473:pathology; D054852:Small Molecule Libraries / Q000494:pharmacology; D014162:Transfection
chemical_list: D000075002:Bestrophins; D050505:Mutant Proteins; D010654:Phenylbutyrates; D054852:Small Molecule Libraries; C075773:4-phenylbutyric acid
keywords: 4-phenylbutyrate; Autosomal recessive bestrophinopathy; Bestrophin-1; Chemical chaperone