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Li JX, Meng LR, Hou BK, Hao XL, Wang DJ, Qu LH, Li ZH, Zhang L, Jin X. Detection of Novel BEST1 Variations in Autosomal Recessive Bestrophinopathy Using Third-generation Sequencing. Curr Med Sci 2024; 44:419-425. [PMID: 38619684 DOI: 10.1007/s11596-024-2865-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 03/07/2024] [Indexed: 04/16/2024]
Abstract
OBJECTIVE Autosomal recessive bestrophinopathy (ARB), a retinal degenerative disease, is characterized by central visual loss, yellowish multifocal diffuse subretinal deposits, and a dramatic decrease in the light peak on electrooculogram. The potential pathogenic mechanism involves mutations in the BEST1 gene, which encodes Ca2+-activated Cl- channels in the retinal pigment epithelium (RPE), resulting in degeneration of RPE and photoreceptor. In this study, the complete clinical characteristics of two Chinese ARB families were summarized. METHODS Pacific Biosciences (PacBio) single-molecule real-time (SMRT) sequencing was performed on the probands to screen for disease-causing gene mutations, and Sanger sequencing was applied to validate variants in the patients and their family members. RESULTS Two novel mutations, c.202T>C (chr11:61722628, p.Y68H) and c.867+97G>A, in the BEST1 gene were identified in the two Chinese ARB families. The novel missense mutation BEST1 c.202T>C (p.Y68H) resulted in the substitution of tyrosine with histidine in the N-terminal region of transmembrane domain 2 of bestrophin-1. Another novel variant, BEST1 c.867+97G>A (chr11:61725867), located in intron 7, might be considered a regulatory variant that changes allele-specific binding affinity based on motifs of important transcriptional regulators. CONCLUSION Our findings represent the first use of third-generation sequencing (TGS) to identify novel BEST1 mutations in patients with ARB, indicating that TGS can be a more accurate and efficient tool for identifying mutations in specific genes. The novel variants identified further broaden the mutation spectrum of BEST1 in the Chinese population.
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Affiliation(s)
- Jia-Xun Li
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Ling-Rui Meng
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Bao-Ke Hou
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Xiao-Lu Hao
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Da-Jiang Wang
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Ling-Hui Qu
- Department of Ophthalmology, the 74th Army Group Hospital, Guangzhou, 510318, China
| | - Zhao-Hui Li
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Lei Zhang
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China
| | - Xin Jin
- Department of Senior Ophthalmology, the Third Medical Center of PLA General Hospital, Beijing, 100853, China.
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Zhang TT, Lei QQ, He J, Guan X, Zhang X, Huang Y, Zhou ZY, Fan RX, Wang T, Li CX, Shang JY, Lin ZM, Peng WL, Xia LK, He YL, Hong CY, Ou JS, Pang RP, Fan XP, Huang H, Zhou JG. Bestrophin3 Deficiency in Vascular Smooth Muscle Cells Activates MEKK2/3-MAPK Signaling to Trigger Spontaneous Aortic Dissection. Circulation 2023; 148:589-606. [PMID: 37203562 DOI: 10.1161/circulationaha.122.063029] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 04/27/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Aortic dissection (AD) is a fatal cardiovascular disorder without effective medications due to unclear pathogenic mechanisms. Bestrophin3 (Best3), the predominant isoform of bestrophin family in vessels, has emerged as critical for vascular pathological processes. However, the contribution of Best3 to vascular diseases remains elusive. METHODS Smooth muscle cell-specific and endothelial cell-specific Best3 knockout mice (Best3SMKO and Best3ECKO, respectively) were engineered to investigate the role of Best3 in vascular pathophysiology. Functional studies, single-cell RNA sequencing, proteomics analysis, and coimmunoprecipitation coupled with mass spectrometry were performed to evaluate the function of Best3 in vessels. RESULTS Best3 expression in aortas of human AD samples and mouse AD models was decreased. Best3SMKO but not Best3ECKO mice spontaneously developed AD with age, and the incidence reached 48% at 72 weeks of age. Reanalysis of single-cell transcriptome data revealed that reduction of fibromyocytes, a fibroblast-like smooth muscle cell cluster, was a typical feature of human ascending AD and aneurysm. Consistently, Best3 deficiency in smooth muscle cells decreased the number of fibromyocytes. Mechanistically, Best3 interacted with both MEKK2 and MEKK3, and this interaction inhibited phosphorylation of MEKK2 at serine153 and MEKK3 at serine61. Best3 deficiency induced phosphorylation-dependent inhibition of ubiquitination and protein turnover of MEKK2/3, thereby activating the downstream mitogen-activated protein kinase signaling cascade. Furthermore, restoration of Best3 or inhibition of MEKK2/3 prevented AD progression in angiotensin II-infused Best3SMKO and ApoE-/- mice. CONCLUSIONS These findings unveil a critical role of Best3 in regulating smooth muscle cell phenotypic switch and aortic structural integrity through controlling MEKK2/3 degradation. Best3-MEKK2/3 signaling represents a novel therapeutic target for AD.
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Affiliation(s)
- Ting-Ting Zhang
- Program of Cardiovascular Research, The Eighth Affiliated Hospital (T.-T.Z., H.H., J.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Department of Cardiology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong, China (T.-T.Z., Y.H., H.H.)
| | - Qing-Qing Lei
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jie He
- Department of Cardiovascular Surgery, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangdong, China (J.H., X.-P.F.)
- Division of Vascular Surgery, National-Guangdong Joint Engineering Laboratory for Diagnosis and Treatment of Vascular Diseases (J.H.), NHC Key Laboratory of Assisted Circulation (Sun Yat-Sen University), The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xin Guan
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xin Zhang
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ying Huang
- Department of Cardiology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong, China (T.-T.Z., Y.H., H.H.)
| | - Zi-Yue Zhou
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Rui-Xin Fan
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (R.-X.F., C.-X.L.)
| | - Ting Wang
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Chen-Xi Li
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (R.-X.F., C.-X.L.)
| | - Jin-Yan Shang
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhuo-Miao Lin
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wan-Li Peng
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Li-Kai Xia
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yu-Ling He
- Department of Pharmacology, Cardiac and Cerebrovascular Research Center (T.-T.Z., Q.-Q.L., X.G., X.Z., Z.-Y.Z., T.W., J.-Y.S., Z.-M.L., W.-L.P., L.-K.X., Y.-L.H., Z.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Chuan-Ying Hong
- Department of Physiology, Pain Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China (C.-Y.H., R.-P.P.)
| | - Jing-Song Ou
- Division of Cardiac Surgery, National-Guangdong Joint Engineering Laboratory for Diagnosis and Treatment of Vascular Diseases (J.-S.O.) NHC Key Laboratory of Assisted Circulation (Sun Yat-Sen University), The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Rui-Ping Pang
- Department of Physiology, Pain Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China (C.-Y.H., R.-P.P.)
| | - Xiao-Ping Fan
- Department of Cardiovascular Surgery, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangdong, China (J.H., X.-P.F.)
| | - Hui Huang
- Program of Cardiovascular Research, The Eighth Affiliated Hospital (T.-T.Z., H.H., J.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Department of Cardiology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, Guangdong, China (T.-T.Z., Y.H., H.H.)
| | - Jia-Guo Zhou
- Program of Cardiovascular Research, The Eighth Affiliated Hospital (T.-T.Z., H.H., J.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Brain Function and Disease (J.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Program of Kidney and Cardiovascular Disease, The Fifth Affiliated Hospital (J.-G.Z.), Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangzhou Institute of Cardiovascular Disease, Affiliated Guangzhou Women and Children's Hospital, School of Basic Medical Sciences, Guangzhou Medical University, Guangdong, China (J.-G.Z.)
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Impaired Bestrophin Channel Activity in an iPSC-RPE Model of Best Vitelliform Macular Dystrophy (BVMD) from an Early Onset Patient Carrying the P77S Dominant Mutation. Int J Mol Sci 2022; 23:ijms23137432. [PMID: 35806438 PMCID: PMC9266689 DOI: 10.3390/ijms23137432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/01/2022] [Indexed: 01/25/2023] Open
Abstract
Best Vitelliform Macular dystrophy (BVMD) is the most prevalent of the distinctive retinal dystrophies caused by mutations in the BEST1 gene. This gene, which encodes for a homopentameric calcium-activated ion channel, is crucial for the homeostasis and function of the retinal pigment epithelia (RPE), the cell type responsible for recycling the visual pigments generated by photoreceptor cells. In BVMD patients, mutations in this gene induce functional problems in the RPE cell layer with an accumulation of lipofucsin that evolves into cell death and loss of sight. In this work, we employ iPSC-RPE cells derived from a patient with the p.Pro77Ser dominant mutation to determine the correlation between this variant and the ocular phenotype. To this purpose, gene and protein expression and localization are evaluated in iPSC-RPE cells along with functional assays like phagocytosis and anion channel activity. Our cell model shows no differences in gene expression, protein expression/localization, or phagocytosis capacity, but presents an increased chloride entrance, indicating that the p.Pro77Ser variant might be a gain-of-function mutation. We hypothesize that this variant disturbs the neck region of the BEST1 channel, affecting channel function but maintaining cell homeostasis in the short term. This data shed new light on the different phenotypes of dominant mutations in BEST1, and emphasize the importance of understanding its molecular mechanisms. Furthermore, the data widen the knowledge of this pathology and open the door for a better diagnosis and prognosis of the disease.
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Singh Grewal S, Smith JJ, Carr AJF. Bestrophinopathies: perspectives on clinical disease, Bestrophin-1 function and developing therapies. Ther Adv Ophthalmol 2021; 13:2515841421997191. [PMID: 33738427 PMCID: PMC7934022 DOI: 10.1177/2515841421997191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 01/27/2021] [Indexed: 12/17/2022] Open
Abstract
Bestrophinopathies are a group of clinically distinct inherited retinal dystrophies that typically affect the macular region, an area synonymous with central high acuity vision. This spectrum of disorders is caused by mutations in bestrophin1 (BEST1), a protein thought to act as a Ca2+-activated Cl- channel in the retinal pigment epithelium (RPE) of the eye. Although bestrophinopathies are rare, over 250 individual pathological mutations have been identified in the BEST1 gene, with many reported to have various clinical expressivity and incomplete penetrance. With no current clinical treatments available for patients with bestrophinopathies, understanding the role of BEST1 in cells and the pathological pathways underlying disease has become a priority. Induced pluripotent stem cell (iPSC) technology is helping to uncover disease mechanisms and develop treatments for RPE diseases, like bestrophinopathies. Here, we provide a comprehensive review of the pathophysiology of bestrophinopathies and highlight how patient-derived iPSC-RPE are being used to test new genomic therapies in vitro.
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Affiliation(s)
| | - Joseph J Smith
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Amanda-Jayne F Carr
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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Liu J, Taylor RL, Baines RA, Swanton L, Freeman S, Corneo B, Patel A, Marmorstein A, Knudsen T, Black GC, Manson F. Small Molecules Restore Bestrophin 1 Expression and Function of Both Dominant and Recessive Bestrophinopathies in Patient-Derived Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2020; 61:28. [PMID: 32421148 PMCID: PMC7405785 DOI: 10.1167/iovs.61.5.28] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Purpose Bestrophinopathies are a group of untreatable inherited retinal dystrophies caused by mutations in the retinal pigment epithelium (RPE) Cl− channel bestrophin 1. We tested whether sodium phenylbutyrate (4PBA) could rescue the function of mutant bestrophin 1 associated with autosomal dominant and recessive disease. We then sought analogues of 4PBA with increased potency and determined the mode of action for 4PBA and a lead compound 2-naphthoxyacetic acid (2-NOAA). Lastly, we tested if 4PBA and 2-NOAA could functionally rescue bestrophin 1 function in RPE generated from induced pluripotent stem cells (iPSC-RPEs) derived from patients with a dominant or recessive bestrophinopathy. Methods Global and plasma membrane expression was determined by Western blot and immunofluorescent microscopy, respectively. The effect of 4PBA and 2-NOAA on transcription was measured by quantitative RT-PCR and the rate of protein turnover by cycloheximide chase and Western blot. Channel function was measured by whole-cell patch clamp. Results 4PBA and 2-NOAA can rescue the global and membrane expression of mutant bestrophin 1 associated with autosomal dominant disease (Best vitelliform macular dystrophy [BVMD]) and autosome recessive bestrophinopathy (ARB), and these small molecules have different modes of action. Both 4PBA and 2-NOAA significantly increased the channel function of mutant BVMD and ARB bestrophin 1 in HEK293T and iPSC-RPE cells derived from patients with BVMD and ARB. For 4PBA, the increased mutant channel function in BVMD and ARB iPSC-RPE was equal to that of wild-type iPSC-RPE bestrophin 1. Conclusions The restoration of bestrophin 1 function in patient-derived RPE confirms the US Food and Drug Administration–approved drug 4PBA as a promising therapeutic treatment for bestrophinopathies.
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Sensing through Non-Sensing Ocular Ion Channels. Int J Mol Sci 2020; 21:ijms21186925. [PMID: 32967234 PMCID: PMC7554890 DOI: 10.3390/ijms21186925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. In the eye, ion channels are involved in various physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to an array of blindness, termed ocular channelopathies. These mutations result in either a loss- or gain-of channel functions affecting the structure, assembly, trafficking, and localization of channel proteins. A dominant-negative effect is caused in a few channels formed by the assembly of several subunits that exist as homo- or heteromeric proteins. Here, we review the role of different mutations in switching a “sensing” ion channel to “non-sensing,” leading to ocular channelopathies like Leber’s congenital amaurosis 16 (LCA16), cone dystrophy, congenital stationary night blindness (CSNB), achromatopsia, bestrophinopathies, retinitis pigmentosa, etc. We also discuss the various in vitro and in vivo disease models available to investigate the impact of mutations on channel properties, to dissect the disease mechanism, and understand the pathophysiology. Innovating the potential pharmacological and therapeutic approaches and their efficient delivery to the eye for reversing a “non-sensing” channel to “sensing” would be life-changing.
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Mutation-Dependent Pathomechanisms Determine the Phenotype in the Bestrophinopathies. Int J Mol Sci 2020; 21:ijms21051597. [PMID: 32111077 PMCID: PMC7084480 DOI: 10.3390/ijms21051597] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022] Open
Abstract
Best vitelliform macular dystrophy (BD), autosomal dominant vitreoretinochoroidopathy (ADVIRC), and the autosomal recessive bestrophinopathy (ARB), together known as the bestrophinopathies, are caused by mutations in the bestrophin-1 (BEST1) gene affecting anion transport through the plasma membrane of the retinal pigment epithelium (RPE). To date, while no treatment exists a better understanding of BEST1-related pathogenesis may help to define therapeutic targets. Here, we systematically characterize functional consequences of mutant BEST1 in thirteen RPE patient cell lines differentiated from human induced pluripotent stem cells (hiPSCs). Both BD and ARB hiPSC-RPEs display a strong reduction of BEST1-mediated anion transport function compared to control, while ADVIRC mutations trigger an increased anion permeability suggesting a stabilized open state condition of channel gating. Furthermore, BD and ARB hiPSC-RPEs differ by the degree of mutant protein turnover and by the site of subcellular protein quality control with adverse effects on lysosomal pH only in the BD-related cell lines. The latter finding is consistent with an altered processing of catalytic enzymes in the lysosomes. The present study provides a deeper insight into distinct molecular mechanisms of the three bestrophinopathies facilitating functional categorization of the more than 300 known BEST1 mutations that result into the distinct retinal phenotypes.
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Ye P, Xu J, Luo Y, Su Z, Yao K. Familial autosomal recessive bestrophinopathy: identification of a novel variant in BEST1 gene and the specific metabolomic profile. BMC MEDICAL GENETICS 2020; 21:16. [PMID: 31969119 PMCID: PMC6977271 DOI: 10.1186/s12881-020-0951-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Autosomal recessive bestrophinopathy (ARB) is a retinal degenerative disorder caused by BEST1 mutations with autosomal recessive inheritance. We aim to map a comprehensive genomic and metabolomic profile of a consanguineous Chinese family with ARB. METHODS Ophthalmic examinations were performed on the affected patients with ARB. The proband was screened for potential causative mutations in a panel with 256 known retinal disease genes by using target capture sequencing. The related mutation was further validated and segregated in the family members by Sanger sequencing. In silico prediction tools were used for pathogenicity assessment. A UHPLC-MS/MS metabolomic analysis was performed to explore the disease-associated metabolic feature. RESULTS The affected patients from this family were characterized by low vision, the presence of subretinal fluid, macular edema, and hyperopia with coincidental angle closure. DNA sequencing identified a novel missense mutation in the BEST1 gene c.646G > A (p.Val216Ile) of the proband. Sanger sequencing further confirmed the mutation. The missense mutation was co-segregation across the pedigree and predicted to be deleterious by SIFT (0.017). The blood metabolic profiles were highly similar among all family members probably because of the same lifestyle, habitat and genomic background. However, ARB patients presented a significant deregulation of metabolites, such as citric acid, L-Threonic acid, and eicosapentaenoic acid. CONCLUSIONS We identified a novel disease-associated variant in the BEST1 gene as well as a disease-specific metabolic feature in familial ARB. Our findings helped improve the understanding of ARB mechanisms.
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Affiliation(s)
- Panpan Ye
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Eye Hospital, Zhejiang University, Hangzhou, China
| | - Jia Xu
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yueqiu Luo
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Eye Hospital, Zhejiang University, Hangzhou, China
| | - Zhitao Su
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Eye Hospital, Zhejiang University, Hangzhou, China
| | - Ke Yao
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Eye Hospital, Zhejiang University, Hangzhou, China
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Witsberger E, Marmorstein A, Pulido J. Diffuse Outer Layer Opacification: A Novel Finding in Patients With Autosomal Recessive Bestrophinopathy. Asia Pac J Ophthalmol (Phila) 2019; 8:469-475. [PMID: 31789649 PMCID: PMC6903339 DOI: 10.1097/apo.0000000000000261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Autosomal recessive bestrophinopathy (ARB) is a rare inherited retinal dystrophy resulted from mutations in bestrophin-1 (BEST1) which affect functioning of the retinal pigment epithelium (RPE). Descriptions of disease findings in patients with ARB to date have focused only on macular changes. In this case series, we report previously undescribed mid-peripheral retinal changes occurring in 4 patients with ARB. DESIGN Case series. METHODS A single-center, retrospective review of medical records from Mayo Clinic patients with ARB was performed. Imaging reviewed include fundus photography, fundus autofluorescence, spectral domain optical coherence tomography (OCT), and fluorescein angiography. Demographic information and disease progression were noted. RESULTS 4 affected patients from 3 families were identified. All 4 patients were female, and mean age was 12.5 years (range 5-19 years). Diffuse mid-peripheral whitening was consistently noted on fundus photography. Concomitant OCT imaging demonstrated areas of hyperreflectivity in the photoreceptor outer segment layer in areas corresponding to whitening seen on fundus photography. In 1 patient who was followed for 12 years, this finding persisted. Subretinal fluid was also consistently present. Other pathologic imaging findings observed in each patient were in agreement with previous reports of ARB. CONCLUSIONS This is the first descriptive report of pathologic findings occurred beyond the posterior pole in patients with ARB. These mid-peripheral retinal changes potentially imply that the entirety of the RPE is affected by mutations in BEST1, as also suggested by previous electro-oculogram (EOG) findings. Such implications will be important when developing treatment trials, as past trials have focused only on the posterior pole of the RPE.
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Milenkovic A, Schmied D, Tanimoto N, Seeliger MW, Sparrow JR, Weber BHF. The Y227N mutation affects bestrophin-1 protein stability and impairs sperm function in a mouse model of Best vitelliform macular dystrophy. Biol Open 2019; 8:bio.041335. [PMID: 31201163 PMCID: PMC6679414 DOI: 10.1242/bio.041335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Human bestrophin-1 (BEST1) is an integral membrane protein known to function as a Ca2+-activated and volume-regulated chloride channel. The majority of disease-associated mutations in BEST1 constitute missense mutations and were shown in vitro to lead to a reduction in mutant protein half-life causing Best disease (BD), a rare autosomal dominant macular dystrophy. To further delineate BEST1-associated pathology in vivo and to provide an animal model useful to explore experimental treatment efficacies, we have generated a knock-in mouse line (Best1Y227N). Heterozygous and homozygous mutants revealed no significant ocular abnormalities up to 2 years of age. In contrast, knock-in animals demonstrated a severe phenotype in the male reproductive tract. In heterozygous Best1Y227N males, Best1 protein was significantly reduced in testis and almost absent in homozygous mutant mice, although mRNA transcription of wild-type and knock-in allele is present and similar in quantity. Degradation of mutant Best1 protein in testis was associated with adverse effects on sperm motility and the capability to fertilize eggs. Based on these results, we conclude that mice carrying the Best1 Y227N mutation reveal a reproducible pathologic phenotype and thus provide a valuable in vivo tool to evaluate efficacy of drug therapies aimed at restoring Best1 protein stability and function.
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Affiliation(s)
- Andrea Milenkovic
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Denise Schmied
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Centre for Ophthalmology, Institute for Ophthalmic Research, 72076 Tübingen, Germany.,Department of Ophthalmology, University of Kiel, 24105 Kiel, Germany
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Centre for Ophthalmology, Institute for Ophthalmic Research, 72076 Tübingen, Germany
| | - Janet R Sparrow
- Department of Ophthalmology, Harkness Eye Institute, Columbia University Medical Center, 10032 New York, USA
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
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11
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Jaffal L, Joumaa WH, Assi A, Helou C, Condroyer C, El Dor M, Cherfan G, Zeitz C, Audo I, Zibara K, El Shamieh S. Novel Missense Mutations in BEST1 Are Associated with Bestrophinopathies in Lebanese Patients. Genes (Basel) 2019; 10:genes10020151. [PMID: 30781664 PMCID: PMC6409913 DOI: 10.3390/genes10020151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/07/2019] [Accepted: 02/07/2019] [Indexed: 12/25/2022] Open
Abstract
To identify Bestrophin 1 (BEST1) causative mutations in six Lebanese patients from three families, of whom four had a presumed clinical diagnosis of autosomal recessive bestrophinopathy (ARB) and two showed a phenotype with a single vitelliform lesion, patients were subjected to standard ophthalmic examinations. In addition, BEST1 exons and their flanking regions were amplified and sequenced by Sanger sequencing. Co-segregation and detailed bio-informatic analyses were performed. Clinical examination results were consistent with ARB diagnosis for all index patients showing multifocal vitelliform lesions and a markedly reduced light peak in the electrooculogram, including the two patients with a single vitelliform lesion. In all cases, most likely disease-causing BEST1 mutations co-segregated with the phenotype. The ARB cases showed homozygous missense variants (M1, c.209A>G, p.(Asp70Gly) in exon 3, M2, c.1403C>T; p.(Pro468Leu) in exon 10 and M3, c.830C>T, p.(Thr277Met) in exon 7), while the two patients with a single vitelliform lesion were compound heterozygous for M1 and M2. To our knowledge, this is the first study describing mutations in Lebanese patients with bestrophinopathy, where novel biallelic BEST1 mutations associated with two phenotypes were identified. Homozygous mutations were associated with multifocal lesions, subretinal fluid, and intraretinal cysts, whereas compound heterozygous ones were responsible for a single macular vitelliform lesion.
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Affiliation(s)
- Lama Jaffal
- Department of Biological and Environmental Sciences, Faculty of Science, Beirut Arab University, Debbieh 1107 2809, Lebanon.
| | - Wissam H Joumaa
- Rammal Hassan Rammal Research Laboratory, PhyToxE research group, Department of Life and Earth Sciences, Faculty of Sciences, Lebanese University, Nabatieh 1700, Lebanon.
| | - Alexandre Assi
- Retinal Service, Beirut Eye & ENT Specialist Hospital, Beirut 1106, Lebanon.
| | - Charles Helou
- Retinal Service, Beirut Eye & ENT Specialist Hospital, Beirut 1106, Lebanon.
| | - Christel Condroyer
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France.
| | - Maya El Dor
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon.
| | - Georges Cherfan
- Retinal Service, Beirut Eye & ENT Specialist Hospital, Beirut 1106, Lebanon.
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France.
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France.
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC1423, F-75012 Paris, France.
- University College London Institute of Ophthalmology, London EC1V 9EL, UK.
| | - Kazem Zibara
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon.
- ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon.
| | - Said El Shamieh
- Rammal Hassan Rammal Research Laboratory, PhyToxE research group, Department of Life and Earth Sciences, Faculty of Sciences, Lebanese University, Nabatieh 1700, Lebanon.
- Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut 1107 2809, Lebanon.
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12
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Milenkovic A, Milenkovic VM, Wetzel CH, Weber BHF. BEST1 protein stability and degradation pathways differ between autosomal dominant Best disease and autosomal recessive bestrophinopathy accounting for the distinct retinal phenotypes. Hum Mol Genet 2019; 27:1630-1641. [PMID: 29668979 PMCID: PMC5905664 DOI: 10.1093/hmg/ddy070] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/19/2018] [Indexed: 12/21/2022] Open
Abstract
Mutations in bestrophin-1 (BEST1) are associated with distinct retinopathies, notably three forms with autosomal dominant inheritance and one condition with an autosomal recessive mode of transmission. The molecular mechanisms underlying their distinct retinal phenotypes are mostly unknown. Although heterozygous missense mutations in BEST1 reveal dominant-negative effects in patients with autosomal dominant Best disease (BD), heterozygous mutations associated with autosomal recessive bestrophinopathy (ARB) display no disease phenotype. Here we show that the recessive mutations trigger a strong and fast protein degradation process in the endoplasmic reticulum (ER), thereby favoring a decreased stoichiometry of mutant versus normal BEST1 subunits in the assembly of the homo-pentameric BEST1 chloride channel. In contrast, dominant mutations escape ER-associated degradation and are subjected to a slightly delayed post-ER degradation via the endo-lysosomal degradation pathway. As a result, increased formation of a non-functional BEST1 channel occurs due to a roughly equimolar incorporation of normal and mutant BEST1 subunits into the channel complex. Taken together, our data provide insight into the molecular pathways of dominantly and recessively acting BEST1 missense mutations suggesting that the site of subcellular protein quality control as well as the rate and degree of mutant protein degradation are ultimately responsible for the distinct retinal disease phenotypes in BD and ARB.
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Affiliation(s)
- Andrea Milenkovic
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Vladimir M Milenkovic
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93053 Regensburg, Germany
| | - Christian H Wetzel
- Department of Psychiatry and Psychotherapy, Molecular Neurosciences, University of Regensburg, 93053 Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
- To whom correspondence should be addressed at: Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauß-Allee 11, D-93053 Regensburg, Germany. Tel: +49 9419445400; Fax: +49 9419445402;
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13
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Marmorstein AD, Johnson AA, Bachman LA, Andrews-Pfannkoch C, Knudsen T, Gilles BJ, Hill M, Gandhi JK, Marmorstein LY, Pulido JS. Mutant Best1 Expression and Impaired Phagocytosis in an iPSC Model of Autosomal Recessive Bestrophinopathy. Sci Rep 2018. [PMID: 29540715 PMCID: PMC5852082 DOI: 10.1038/s41598-018-21651-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Autosomal recessive bestrophinopathy (ARB) is caused by mutations in the gene BEST1 which encodes bestrophin 1 (Best1), an anion channel expressed in retinal pigment epithelial (RPE) cells. It has been hypothesized that ARB represents the human null phenotype for BEST1 and that this occurs due to nonsense mediated decay (NMD). To test this hypothesis, we generated induced pluripotent stem cells (iPSCs) from a patient with ARB and her parents. After differentiation to retinal pigment epithelial (iPSC-RPE) cells, both BEST1 mRNA and Best1 protein expression were compared to controls. BEST1 mRNA expression levels, determined by quantitative PCR, were similar in ARB iPSC-RPE, parental cells, and genetically unrelated controls. Western blotting revealed that CRALBP and RPE65 were expressed within the range delineated by unrelated controls in iPSC-RPE from the ARB donor and her parents. Best1 protein was detected in different clones of ARB iPSC-RPE, but at reduced levels compared to all controls. When tested for the ability to phagocytose photoreceptor outer segments, ARB iPSC-RPE exhibited impaired internalization. These data suggest that impaired phagocytosis is a trait common to the bestrophinopathies. Furthermore, ARB is not universally the result of NMD and ARB, in this patient, is not due to the absence of Best1.
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Affiliation(s)
- Alan D Marmorstein
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
| | - Adiv A Johnson
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Lori A Bachman
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | | | - Travis Knudsen
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Benjamin J Gilles
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Matthew Hill
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Jarel K Gandhi
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Lihua Y Marmorstein
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Jose S Pulido
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
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14
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Campbell M, Cassidy PS, O'Callaghan J, Crosbie DE, Humphries P. Manipulating ocular endothelial tight junctions: Applications in treatment of retinal disease pathology and ocular hypertension. Prog Retin Eye Res 2017; 62:120-133. [PMID: 28951125 DOI: 10.1016/j.preteyeres.2017.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/01/2017] [Accepted: 09/20/2017] [Indexed: 11/25/2022]
Abstract
Protein levels of endothelial tight-junctions of the inner retinal microvasculature, together with those of Schlemm's canal, can be readily manipulated by RNA interference (RNAi), resulting in the paracellular clefts between such cells to be reversibly modulated. This facilitates access to the retina of systemically-deliverable low molecular weight, potentially therapeutic compounds, while also allowing potentially toxic material, for example, soluble Amyloid-β1-40, to be removed from the retina into the peripheral circulation. The technique has also been shown to be highly effective in alleviation of pathological cerebral oedema and we speculate that it may therefore have similar utility in the oedematous retina. Additionally, by manipulating endothelial tight-junctions of Schlemm's canal, inflow of aqueous humour from the trabecular meshwork into the Canal can be radically enhanced, suggesting a novel avenue for control of intraocular pressure. Here, we review the technology underlying this approach together with specific examples of clinical targets that are, or could be, amenable to this novel form of genetic intervention.
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Affiliation(s)
- Matthew Campbell
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland.
| | - Paul S Cassidy
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland
| | - Jeffrey O'Callaghan
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland
| | - Darragh E Crosbie
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland
| | - Pete Humphries
- Smurfit Institute of Genetics, Lincoln Place Gate, Trinity College Dublin, Dublin 2, Ireland.
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15
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Lin Y, Li T, Gao H, Lian Y, Chen C, Zhu Y, Li Y, Liu B, Zhou W, Jiang H, Liu X, Zhao X, Liang X, Jin C, Huang X, Lu L. Bestrophin 1 gene analysis and associated clinical findings in a Chinese patient with Best vitelliform macular dystrophy. Mol Med Rep 2017; 16:4751-4755. [PMID: 28791410 PMCID: PMC5647057 DOI: 10.3892/mmr.2017.7174] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 06/15/2017] [Indexed: 01/21/2023] Open
Abstract
The aim of the present study was to investigate the clinical characteristics and the underlying genetic causes of Best vitelliform macular dystrophy (BVMD) in a sporadic case in a Chinese patient. A 10‑year‑old boy was diagnosed with BVMD; complete ophthalmic examinations were performed, including best‑corrected visual acuity, intraocular pressure, slit‑lamp examination, fundus photograph, optical coherence tomography and fundus fluorescein angiography imaging. Genomic DNA was extracted from leukocytes of the peripheral blood collected from this patient and his family members. DNA samples from 200 unrelated subjects from the Chinese population were used as controls. A total of 11 exons of the bestrophin 1 (BEST1) gene were amplified by polymerase chain reaction and directly sequenced. The results revealed that the patient presented with yellowish lesions in the macular area. Heterozygous mutations c.292G>A (p.Glu98Lys) in exon 4 and c.1608C>T (p.Thr536Thr) in exon 10 of the BEST1 gene were identified in this sporadic case; however, this was not identified in any of his unaffected family members or in the normal controls. The c.292G>A (p.Glu98Lys) mutation has not been previously reported, whereas the c.1608C>T (p.Thr536Thr) mutation is a previously characterized single nucleotide polymorphism (SNP). In conclusion, BEST1 gene mutations and polymorphisms have been reported in diverse ethnic groups, and the present study identified a novel BEST1 gene mutation and an SNP that occurred simultaneously in a Chinese patient with BVMD.
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Affiliation(s)
- Ying Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Tao Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Hongbin Gao
- Guangdong Laboratory Animals Monitoring Institute, Key Laboratory of Guangdong Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Yu Lian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chuan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Yi Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Yonghao Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Wenli Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Hongye Jiang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Xialin Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xiujuan Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xiaoling Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chenjin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xinhua Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Lin Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
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16
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Johnson AA, Guziewicz KE, Lee CJ, Kalathur RC, Pulido JS, Marmorstein LY, Marmorstein AD. Bestrophin 1 and retinal disease. Prog Retin Eye Res 2017; 58:45-69. [PMID: 28153808 DOI: 10.1016/j.preteyeres.2017.01.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 12/18/2022]
Abstract
Mutations in the gene BEST1 are causally associated with as many as five clinically distinct retinal degenerative diseases, which are collectively referred to as the "bestrophinopathies". These five associated diseases are: Best vitelliform macular dystrophy, autosomal recessive bestrophinopathy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy, and retinitis pigmentosa. The most common of these is Best vitelliform macular dystrophy. Bestrophin 1 (Best1), the protein encoded by the gene BEST1, has been the subject of a great deal of research since it was first identified nearly two decades ago. Today we know that Best1 functions as both a pentameric anion channel and a regulator of intracellular Ca2+ signaling. Best1 is an integral membrane protein which, within the eye, is uniquely expressed in the retinal pigment epithelium where it predominantly localizes to the basolateral plasma membrane. Within the brain, Best1 expression has been documented in both glial cells and astrocytes where it functions in both tonic GABA release and glutamate transport. The crystal structure of Best1 has revealed critical information about how Best1 functions as an ion channel and how Ca2+ regulates that function. Studies using animal models have led to critical insights into the physiological roles of Best1 and advances in stem cell technology have allowed for the development of patient-derived, "disease in a dish" models. In this article we review our knowledge of Best1 and discuss prospects for near-term clinical trials to test therapies for the bestrophinopathies, a currently incurable and untreatable set of diseases.
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Affiliation(s)
- Adiv A Johnson
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA; Nikon Instruments, Melville, NY, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C Justin Lee
- Center for Neuroscience and Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ravi C Kalathur
- New York Structural Biology Center, New York Consortium on Membrane Protein Structure, New York, NY, USA
| | - Jose S Pulido
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
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