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Liberski S, Confalonieri F, Cofta S, Petrovski G, Kocięcki J. Ocular Changes in Cystic Fibrosis: A Review. Int J Mol Sci 2024; 25:6692. [PMID: 38928397 PMCID: PMC11203677 DOI: 10.3390/ijms25126692] [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: 04/22/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Cystic fibrosis (CF), also known as mucoviscidosis, is the most common autosomal recessive genetic disease in the Caucasian population, with an estimated frequency of 1:2000-3000 live births. CF results from the mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene localized in the long arm of chromosome 7. The product of CFTR gene expression is CFTR protein, an adenosine triphosphate (ATP)-binding cassette (ABC) transporter that regulates the transport of chloride ions (Cl-) across the apical cell membrane. Primary manifestations of CF include chronic lung and pancreas function impairment secondary to the production of thick, sticky mucus resulting from dehydrated secretions. It is well known that CF can cause both anterior and posterior ocular abnormalities. Conjunctival and corneal xerosis and dry eye disease symptoms are the most characteristic manifestations in the anterior segment. In contrast, the most typical anatomical and functional changes relating to the posterior segment of the eye include defects in the retinal nerve fiber layer (RNFL), vascular abnormalities, and visual disturbances, such as reduced contrast sensitivity and abnormal dark adaptation. However, the complete background of ophthalmic manifestations in the course of CF has yet to be discovered. This review summarizes the current knowledge regarding ocular changes in cystic fibrosis.
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Affiliation(s)
- Slawomir Liberski
- Department of Ophthalmology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
| | - Filippo Confalonieri
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, 20089 Rozzano, Milan, Italy;
- Department of Biomedical Sciences, Humanitas University, 20090 Pieve Emanuele, Milan, Italy
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway;
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, 0450 Oslo, Norway
| | - Szczepan Cofta
- Department of Respiratory Medicine, Allergology and Pulmonary Oncology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway;
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, 0450 Oslo, Norway
| | - Jarosław Kocięcki
- Department of Ophthalmology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
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Amato A, Wongchaisuwat N, Lamborn A, Schmidt R, Everett L, Yang P, Pennesi ME. Gene therapy in bestrophinopathies: Insights from preclinical studies in preparation for clinical trials. Saudi J Ophthalmol 2023; 37:287-295. [PMID: 38155675 PMCID: PMC10752275 DOI: 10.4103/sjopt.sjopt_175_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 12/30/2023] Open
Abstract
The BEST1 gene encodes bestrophin-1, a homopentameric ion channel expressed in the retinal pigment epithelium (RPE), where it localizes to the basolateral plasma membrane. Pathogenic variants in this gene can cause different autosomal dominant and recessive inherited retinal diseases (IRDs), collectively named "bestrophinopathies." These disorders share a number of clinical and molecular features that make them an appealing target for gene therapy. Clinically, bestrophinopathies are often slowly progressive with a wide window of opportunity, and the presence of subretinal material (vitelliform deposits and/or fluid) as a hallmark of these conditions provides an easily quantifiable endpoint in view of future clinical trials. From a molecular standpoint, most BEST1 pathogenic variants have been shown to cause either loss of function (LOF) of the protein or a dominant-negative (DN) effect, with a smaller subset causing a toxic gain of function (GOF). Both LOF and DN mutations may be amenable to gene augmentation alone. On the other hand, individuals harboring GOF variants would require a combination of gene silencing and gene augmentation, which has been shown to be effective in RPE cells derived from patients with Best disease. In this article, we review the current knowledge of BEST1-related IRDs and we discuss how their molecular and clinical features are being used to design novel and promising therapeutic strategies.
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Affiliation(s)
- Alessia Amato
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Nida Wongchaisuwat
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Andrew Lamborn
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Ryan Schmidt
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Lesley Everett
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Paul Yang
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Mark E. Pennesi
- Department of Ophthalmic Genetics, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States of America
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3
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Loh KWZ, Liu C, Soong TW, Hu Z. β subunits of voltage-gated calcium channels in cardiovascular diseases. Front Cardiovasc Med 2023; 10:1119729. [PMID: 36818347 PMCID: PMC9931737 DOI: 10.3389/fcvm.2023.1119729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Calcium signaling is required in bodily functions essential for survival, such as muscle contractions and neuronal communications. Of note, the voltage-gated calcium channels (VGCCs) expressed on muscle and neuronal cells, as well as some endocrine cells, are transmembrane protein complexes that allow for the selective entry of calcium ions into the cells. The α1 subunit constitutes the main pore-forming subunit that opens in response to membrane depolarization, and its biophysical functions are regulated by various auxiliary subunits-β, α2δ, and γ subunits. Within the cardiovascular system, the γ-subunit is not expressed and is therefore not discussed in this review. Because the α1 subunit is the pore-forming subunit, it is a prominent druggable target and the focus of many studies investigating potential therapeutic interventions for cardiovascular diseases. While this may be true, it should be noted that the direct inhibition of the α1 subunit may result in limited long-term cardiovascular benefits coupled with undesirable side effects, and that its expression and biophysical properties may depend largely on its auxiliary subunits. Indeed, the α2δ subunit has been reported to be essential for the membrane trafficking and expression of the α1 subunit. Furthermore, the β subunit not only prevents proteasomal degradation of the α1 subunit, but also directly modulates the biophysical properties of the α1 subunit, such as its voltage-dependent activities and open probabilities. More importantly, various isoforms of the β subunit have been found to differentially modulate the α1 subunit, and post-translational modifications of the β subunits further add to this complexity. These data suggest the possibility of the β subunit as a therapeutic target in cardiovascular diseases. However, emerging studies have reported the presence of cardiomyocyte membrane α1 subunit trafficking and expression in a β subunit-independent manner, which would undermine the efficacy of β subunit-targeting drugs. Nevertheless, a better understanding of the auxiliary β subunit would provide a more holistic approach when targeting the calcium channel complexes in treating cardiovascular diseases. Therefore, this review focuses on the post-translational modifications of the β subunit, as well as its role as an auxiliary subunit in modulating the calcium channel complexes.
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Affiliation(s)
- Kelvin Wei Zhern Loh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,Cardiovascular Disease Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Cong Liu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,Cardiovascular Disease Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,Cardiovascular Disease Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,*Correspondence: Tuck Wah Soong,
| | - Zhenyu Hu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,Cardiovascular Disease Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore,Zhenyu Hu,
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Koh W, Park M, Chun YE, Lee J, Shim HS, Park MG, Kim S, Sa M, Joo J, Kang H, Oh SJ, Woo J, Chun H, Lee SE, Hong J, Feng J, Li Y, Ryu H, Cho J, Lee CJ. Astrocytes Render Memory Flexible by Releasing D-Serine and Regulating NMDA Receptor Tone in the Hippocampus. Biol Psychiatry 2022; 91:740-752. [PMID: 34952697 DOI: 10.1016/j.biopsych.2021.10.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 11/02/2022]
Abstract
BACKGROUND NMDA receptor (NMDAR) hypofunction has been implicated in several psychiatric disorders with impairment of cognitive flexibility. However, the molecular mechanism of how NMDAR hypofunction with decreased NMDAR tone causes the impairment of cognitive flexibility has been minimally understood. Furthermore, it has been unclear whether hippocampal astrocytes regulate NMDAR tone and cognitive flexibility. METHODS We employed cell type-specific genetic manipulations, ex vivo electrophysiological recordings, sniffer patch recordings, cutting-edge biosensor for norepinephrine, and behavioral assays to investigate whether astrocytes can regulate NMDAR tone by releasing D-serine and glutamate. Subsequently, we further investigated the role of NMDAR tone in heterosynaptic long-term depression, metaplasticity, and cognitive flexibility. RESULTS We found that hippocampal astrocytes regulate NMDAR tone via BEST1-mediated corelease of D-serine and glutamate. Best1 knockout mice exhibited reduced NMDAR tone and impairments of homosynaptic and α1 adrenergic receptor-dependent heterosynaptic long-term depression, which leads to defects in metaplasticity and cognitive flexibility. These impairments in Best1 knockout mice can be rescued by hippocampal astrocyte-specific BEST1 expression or enhanced NMDAR tone through D-serine supplement. D-serine injection in Best1 knockout mice during initial learning rescues subsequent reversal learning. CONCLUSIONS These findings indicate that NMDAR tone during initial learning is important for subsequent learning, and hippocampal NMDAR tone regulated by astrocytic BEST1 is critical for heterosynaptic long-term depression, metaplasticity, and cognitive flexibility.
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Affiliation(s)
- Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; Department of Neuroscience, Division of BioMedical Science & Technology, Korea Institute of Science and Technology School, Korea University of Science and Technology, Seoul, South Korea; Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Mijeong Park
- Department of Neuroscience, Division of BioMedical Science & Technology, Korea Institute of Science and Technology School, Korea University of Science and Technology, Seoul, South Korea; Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Ye Eun Chun
- Department of Neuroscience, Division of BioMedical Science & Technology, Korea Institute of Science and Technology School, Korea University of Science and Technology, Seoul, South Korea; Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jaekwang Lee
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Hyun Soo Shim
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Mingu Gordon Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea
| | - Sunpil Kim
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea; Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Moonsun Sa
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea
| | - Jinhyeong Joo
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; IBS School, Korea University of Science and Technology, Daejeon, South Korea
| | - Hyunji Kang
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; IBS School, Korea University of Science and Technology, Daejeon, South Korea
| | - Soo-Jin Oh
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul, South Korea; Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Junsung Woo
- Department of Neuroscience, Division of BioMedical Science & Technology, Korea Institute of Science and Technology School, Korea University of Science and Technology, Seoul, South Korea; Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Heejung Chun
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, South Korea; Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jinpyo Hong
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Hoon Ryu
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jeiwon Cho
- Brain and Cognitive Science, Scranton College, Ewha Womans University, Seoul, South Korea
| | - C Justin Lee
- Department of Neuroscience, Division of BioMedical Science & Technology, Korea Institute of Science and Technology School, Korea University of Science and Technology, Seoul, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea; IBS School, Korea University of Science and Technology, Daejeon, South Korea.
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5
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Banderali U, Jain M, Thakur S, Jayanthan A, Belke DD, Giles WR, Narendran A. The T-type Calcium Channel Cav3.1 in Y79 Retinoblastoma Cells is Regulated by the Epidermal Growth Factor Receptor via the MAPK Signaling Pathway. Curr Eye Res 2021; 47:426-435. [PMID: 34674590 DOI: 10.1080/02713683.2021.1988982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE Retinoblastoma is the most frequent intraocular cancer in children. It is also one of the most common causes for enucleation and carries a significant morbidity rate in affected individuals. Hence, studies on its pathophysiological and growth regulatory mechanisms are urgently needed to identify more effective novel therapeutics. METHODS Using the Y79 retinoblastoma cell line, we investigated the electrophysiological and functional activities of the T-type voltage-gated calcium channel Cav3.1, that is constitutively expressed in these cells. We also analyzed the Akt and MAPK signaling pathways downstream of the epidermal growth factor receptor (EGFR) to understand the mechanism responsible for the inhibition of Cav3.1. RESULTS We demonstrate that the EGFR inhibitor Afatinib significantly reduced cell viability and Cav3.1 mRNA expression and electrophysiological activity. At low concentrations (1 µM), Afatinib reduced the amplitude of Cav3.1 current density, whereas at a high concentration (10 µM), it completely abolished the voltage-gated calcium current. Our results show that inhibition of the MAPK pathway by a specific inhibitor VX-11e affected the Cav3.1 current in a dose-dependent manner. VX-11e (50 nM-1 µM) treatment reduced Cav3.1 current densities in Y79 cells, with complete abolishment of Cav3.1 current at higher concentrations (5 µM). We also demonstrate that the specific inhibition of the Akt kinase (using MK-2206) had no effect on the Cav3.1 currents. CONCLUSION Our study provides a functional relationship between the MAPK pathway and EGFR signaling and indicates that the MAPK signaling pathway mediates the control of Cav3.1 by EGFR in retinoblastoma.
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Affiliation(s)
- Umberto Banderali
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, Canada
| | - Mohit Jain
- POETIC Laboratory for Pre-Clinical Studies and the Division of Pediatric Oncology, Alberta Children's Hospital, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Satbir Thakur
- POETIC Laboratory for Pre-Clinical Studies and the Division of Pediatric Oncology, Alberta Children's Hospital, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Aarthi Jayanthan
- POETIC Laboratory for Pre-Clinical Studies and the Division of Pediatric Oncology, Alberta Children's Hospital, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Darrell D Belke
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Wayne R Giles
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Aru Narendran
- POETIC Laboratory for Pre-Clinical Studies and the Division of Pediatric Oncology, Alberta Children's Hospital, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
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6
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Owji AP, Kittredge A, Zhang Y, Yang T. Structure and Function of the Bestrophin family of calcium-activated chloride channels. Channels (Austin) 2021; 15:604-623. [PMID: 34612806 PMCID: PMC8496536 DOI: 10.1080/19336950.2021.1981625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Bestrophins are a family of calcium-activated chloride channels (CaCCs) with relevance to human physiology and a myriad of eye diseases termed "bestrophinopathies". Since the identification of bestrophins as CaCCs nearly two decades ago, extensive studies from electrophysiological and structural biology perspectives have sought to define their key channel features including calcium sensing, gating, inactivation, and anion selectivity. The initial X-ray crystallography studies on the prokaryotic homolog of Best1, Klebsiella pneumoniae (KpBest), and the Best1 homolog from Gallus gallus (chicken Best1, cBest1), laid the foundational groundwork for establishing the architecture of Best1. Recent progress utilizing single-particle cryogenic electron microscopy has further elucidated the molecular mechanism of gating in cBest1 and, separately, the structure of Best2 from Bos taurus (bovine Best2, bBest2). Meanwhile, whole-cell patch clamp, planar lipid bilayer, and other electrophysiologic analyses using these models as well as the human Best1 (hBest1) have provided ample evidence describing the functional properties of the bestrophin channels. This review seeks to consolidate these structural and functional results to paint a broad picture of the underlying mechanisms comprising the bestrophin family's structure-function relationship.
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Affiliation(s)
- Aaron P Owji
- Department of Pharmacology, Columbia University, NY, USA
| | - Alec Kittredge
- Department of Pharmacology, Columbia University, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, NY, USA
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, NY, USA
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7
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BEST Disease and Gene Therapy. Int Ophthalmol Clin 2021; 61:167-172. [PMID: 34584054 DOI: 10.1097/iio.0000000000000376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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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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9
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Shah M, Broadgate S, Shanks M, Clouston P, Yu J, MacLaren RE, Németh AH, Halford S, Downes SM. Association of Clinical and Genetic Heterogeneity With BEST1 Sequence Variations. JAMA Ophthalmol 2021; 138:544-551. [PMID: 32239196 DOI: 10.1001/jamaophthalmol.2020.0666] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Importance Detailed phenotypic information on the spectrum of fundus abnormalities and clinical variability of all phenotypes associated with sequence variations in BEST1 is limited. Objective To report a detailed phenotypic and genetic analysis of a patient cohort with sequence variations in BEST1. Design, Setting, and Participants This retrospective case series took place at the Oxford Eye Hospital in Oxford, UK. Thirty-six patients from a single center with disease-causing sequence variations in BEST1 from 25 different families were analyzed. Data were collected from November 2017 to June 2018, and analysis began April 2018. Main Outcomes and Measures Results of ocular phenotyping and genetic testing using targeted next-generation sequencing to identify BEST1 sequence variations. Results Thirty-six patients from 25 families with disease-causing sequence variations in BEST1 were included. Of 36 patients, 20 (55.6%) were female. Three distinct clinical phenotypes were identified: autosomal recessive bestrophinopathy (ARB), best vitelliform macular dystrophy (BVMD), and adult-onset vitelliform macular dystrophy. The ARB phenotype group comprised 18 patients from 9 families with age in years at symptom onset ranging from less than 10 to 40s. All patients showed a common phenotype of fundus autofluorescence abnormalities, and spectral-domain optical coherence tomography features were similar in all patients with schitic and cystoid changes. A phenotype of a beaten metallic retinal appearance extending from the mid periphery to the far periphery was identified in 8 patients. Four patients from 1 family with ARB were previously reported to have autosomal recessive retinitis pigmentosa but were reclassified as having ARB as part of this study. The BVMD phenotype group comprised 16 patients from 14 families with age at symptom onset ranging from less than 10 to 70s. Fundus features were localized to the macula and consistent with the stage of BVMD. In the adult-onset vitelliform macular dystrophy phenotype group, the age in years at symptom onset varied from 50s to 70s in 2 patients from 2 families. Fundus features included small vitelliform lesions. Where available, electro-oculogram results demonstrated a reduced or absent light rise in all patients with ARB and BVMD. Genetic testing identified 22 variants in BEST1. Conclusions and Relevance These findings support the notion that ARB, BVMD, and adult-onset vitelliform macular dystrophy are clinically distinct and recognizable phenotypes and suggest that the association of autosomal recessive retinitis pigmentosa with sequence variations in BEST1 should be rereviewed.
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Affiliation(s)
- Mital Shah
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Morag Shanks
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford, United Kingdom
| | - Penny Clouston
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford, United Kingdom
| | - Jing Yu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Robert E MacLaren
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Andrea H Németh
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Centre for Genomic Medicine, Oxford, United Kingdom
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Susan M Downes
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.,Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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Kittredge A, Zhang Y, Yang T. Evaluating BEST1 mutations in pluripotent stem cell-derived retinal pigment epithelial cells. Methods Enzymol 2021; 654:365-382. [PMID: 34120722 PMCID: PMC9801436 DOI: 10.1016/bs.mie.2021.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bestrophin-1 (BEST1) is a calcium-activated chloride channel (CaCC) predominantly expressed at the basolateral membrane of the retinal pigment epithelium (RPE). Over 250 mutations in the BEST1 gene have been documented to cause at least five retinal degenerative disorders, commonly termed bestrophinopathies, to which no treatment is currently available. Therefore, understanding the influences of BEST1 disease-causing mutations on the physiological function of BEST1 in RPE is critical for deciphering the pathology of bestrophinopathies and developing therapeutic strategies for patients. However, this task has been impeded by the rarity of BEST1 mutations and limited accessibility to native human RPE cells. Here, we describe a pluripotent stem cell (PSC)-based pipeline for reproducibly generating RPE cells expressing endogenous or exogenous mutant BEST1, which provides us with a powerful "disease-in-a-dish" approach for studying BEST1 mutations in physiological environments.
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Affiliation(s)
- Alec Kittredge
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, United States
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, New York, NY, United States,Corresponding authors: ; ;
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, New York, NY, United States,Corresponding authors: ; ;
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11
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Göppner C, Soria AH, Hoegg-Beiler MB, Jentsch TJ. Cellular basis of ClC-2 Cl - channel-related brain and testis pathologies. J Biol Chem 2021; 296:100074. [PMID: 33187987 PMCID: PMC7949093 DOI: 10.1074/jbc.ra120.016031] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
The ClC-2 chloride channel is expressed in the plasma membrane of almost all mammalian cells. Mutations that cause the loss of ClC-2 function lead to retinal and testicular degeneration and leukodystrophy, whereas gain-of-function mutations cause hyperaldosteronism. Leukodystrophy is also observed with a loss of GlialCAM, a cell adhesion molecule that binds to ClC-2 in glia. GlialCAM changes the localization of ClC-2 and opens the channel by altering its gating. We now used cell type-specific deletion of ClC-2 in mice to show that retinal and testicular degeneration depend on a loss of ClC-2 in retinal pigment epithelial cells and Sertoli cells, respectively, whereas leukodystrophy was fully developed only when ClC-2 was disrupted in both astrocytes and oligodendrocytes. The leukodystrophy of Glialcam-/- mice could not be rescued by crosses with Clcn2op/op mice in which a mutation mimics the "opening" of ClC-2 by GlialCAM. These data indicate that GlialCAM-induced changes in biophysical properties of ClC-2 are irrelevant for GLIALCAM-related leukodystrophy. Taken together, our findings suggest that the pathology caused by Clcn2 disruption results from disturbed extracellular ion homeostasis and identifies the cells involved in this process.
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Affiliation(s)
- Corinna Göppner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Audrey H Soria
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Maja B Hoegg-Beiler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.
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12
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Albuainain A, Alhatlan H, Alkhars W. A novel variant of autosomal recessive best vitelliform macular dystrophy and management of early-onset complications. Saudi J Ophthalmol 2021; 35:159-163. [PMID: 35391813 PMCID: PMC8982945 DOI: 10.4103/1319-4534.337863] [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: 07/06/2020] [Revised: 10/29/2020] [Accepted: 11/23/2020] [Indexed: 12/01/2022] Open
Abstract
To report an adult with autosomal recessive Best vitelliform macular dystrophy with a new homozygous BEST1 mutation, the management of a cystoid macular edema with intravitreal aflibercept in the proband, and the findings in the parents, carriers of heterozygous BEST1 mutations. A 28-year-old female presented with blurry andreduced vision in her both eyes with bilateral vitelliform macular lesions. The patient's parents were also examined. Examinations included electrooculogram (EOGs), imaging studies, and BEST1 gene testing. Interventions included treatment with intravitreal aflibercept for both eyes. The patient presented with visual acuity of 20/20 OD 20/30 OS, RPE changes, multifocal subretinal yellowish deposits resembling vitelliform deposits and subretinal fluids. Cystoid macular edema developed after one month, causing vision reduction (20/28 OD 20/30 OS). Visual acuity recovered to 20/20 OU after serial intravitreal aflibercept injections. The proband showed subnormal EOG Arden ratios. Molecular testing showed the homozygous missense variant c.695T>G p. (IIe232Ser) In exon 6 of the BEST1 mutations and to the best of our knowledge, this variant, which was confirmed by conventional Sanger sequencing, has neither been annotated in databases nor been described in the literature so for (Human Genome Molecular Database 2018.1). In the heterozygous parents, EOGs were subnormal, and minimal autofluorescence changes were seen.
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13
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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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14
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Kwak H, Koh W, Kim S, Song K, Shin JI, Lee JM, Lee EH, Bae JY, Ha GE, Oh JE, Park YM, Kim S, Feng J, Lee SE, Choi JW, Kim KH, Kim YS, Woo J, Lee D, Son T, Kwon SW, Park KD, Yoon BE, Lee J, Li Y, Lee H, Bae YC, Lee CJ, Cheong E. Astrocytes Control Sensory Acuity via Tonic Inhibition in the Thalamus. Neuron 2020; 108:691-706.e10. [PMID: 32905785 DOI: 10.1016/j.neuron.2020.08.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/05/2020] [Accepted: 08/14/2020] [Indexed: 12/17/2022]
Abstract
Sensory discrimination is essential for survival. However, how sensory information is finely controlled in the brain is not well defined. Here, we show that astrocytes control tactile acuity via tonic inhibition in the thalamus. Mechanistically, diamine oxidase (DAO) and the subsequent aldehyde dehydrogenase 1a1 (Aldh1a1) convert putrescine into GABA, which is released via Best1. The GABA from astrocytes inhibits synaptically evoked firing at the lemniscal synapses to fine-tune the dynamic range of the stimulation-response relationship, the precision of spike timing, and tactile discrimination. Our findings reveal a novel role of astrocytes in the control of sensory acuity through tonic GABA release.
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Affiliation(s)
- Hankyul Kwak
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Wuhyun Koh
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea
| | - Sangwoo Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Kiyeong Song
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Jeong-Im Shin
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Jung Moo Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, South Korea
| | - Elliot H Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Jin Young Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 41566, South Korea
| | - Go Eun Ha
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Ju-Eun Oh
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yongmin Mason Park
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea
| | - Sunpil Kim
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, South Korea
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Ji Won Choi
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Ki Hun Kim
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yoo Sung Kim
- Department of Molecular Biology, College of Natural Science, Dankook University, Cheonan 31116, South Korea
| | - Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Dongsu Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Taehwang Son
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, South Korea
| | - Soon Woo Kwon
- Radiation Medicine Clinical Research Division, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea
| | - Ki Duk Park
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology, Seoul 02792, South Korea; KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, South Korea
| | - Bo-Eun Yoon
- Department of Molecular Biology, College of Natural Science, Dankook University, Cheonan 31116, South Korea
| | - Jaeick Lee
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing 100871, China
| | - Hyunbeom Lee
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 41566, South Korea
| | - C Justin Lee
- Division of Bio-Medical Science &Technology, KIST School, Korea University of Science and Technology, Seoul 02792, South Korea; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology, Seoul 02792, South Korea; Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, South Korea.
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea; POSTECH Biotech Center, POSTECH, Pohang, South Korea.
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15
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Woo J, Jang MW, Lee J, Koh W, Mikoshiba K, Lee CJ. The molecular mechanism of synaptic activity-induced astrocytic volume transient. J Physiol 2020; 598:4555-4572. [PMID: 32706443 DOI: 10.1113/jp279741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Neuronal activity causes astrocytic volume change via K+ uptake through TREK-1 containing two-pore domain potassium channels. The volume transient is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel. Intense neuronal activity is synaptically coupled with a physical change in astrocytes via volume transients. ABSTRACT The brain volume changes dynamically and transiently upon intense neuronal activity through a tight regulation of ion concentrations and water movement across the plasma membrane of astrocytes. We have recently demonstrated that an intense neuronal activity and subsequent astrocytic AQP4-dependent volume transient are critical for synaptic plasticity and memory. We have also pharmacologically demonstrated a functional coupling between synaptic activity and the astrocytic volume transient. However, the precise molecular mechanisms of how intense neuronal activity and the astrocytic volume transient are coupled remain unclear. Here we utilized an intrinsic optical signal imaging technique combined with fluorescence imaging using ion sensitive dyes and molecular probes and electrophysiology to investigate the detailed molecular mechanisms in genetically modified mice. We report that a brief synaptic activity induced by a train stimulation (20 Hz, 1 s) causes a prolonged astrocytic volume transient (80 s) via K+ uptake through TREK-1 containing two-pore domain potassium (K2P) channels, but not Kir4.1 or NKCC1. This volume change is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1, but not the volume-regulated anion channel TTYH. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel in astrocytes, but not IP3 R2. In summary, our study identifies several important astrocytic ion channels (AQP4, TREK-1, BEST1, TRPA1) as the key molecules leading to the neuronal activity-dependent volume transient in astrocytes. Our findings reveal new molecular and cellular mechanisms for the synaptic coupling of intense neuronal activity with a physical change in astrocytes via volume transients.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - Jaekwang Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Biology, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
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16
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Ormel L, Lauritzen KH, Schreiber R, Kunzelmann K, Gundersen V. GABA, but Not Bestrophin-1, Is Localized in Astroglial Processes in the Mouse Hippocampus and the Cerebellum. Front Mol Neurosci 2020; 13:135. [PMID: 32848599 PMCID: PMC7399226 DOI: 10.3389/fnmol.2020.00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 07/07/2020] [Indexed: 11/13/2022] Open
Abstract
GABA is proposed to act as a gliotransmitter in the brain. Differences in GABA release from astroglia are thought to underlie differences in tonic inhibition between the cerebellum and the CA1 hippocampus. Here we used quantitative immunogold cytochemistry to localize and compare the levels of GABA in astroglia in these brain regions. We found that the density of GABA immunogold particles was similar in delicate processes of Bergman glia in the cerebellum and astrocytes in the CA1 hippocampus. The astrocytic GABA release is proposed to be mediated by, among others, the Ca2+ activated Cl- channel bestrophin-1. The bestrophin-1 antibodies did not show any significant bestrophin-1 signal in the brain of wt mice, nor in bestrophin-1 knockout mice. The bestrophin-1 signal was low both on Western blots and immunofluorescence laser scanning microscopic images. These results suggest that GABA is localized in astroglia, but in similar concentrations in the cerebellum and CA1 hippocampus, and thus cannot account for differences in tonic inhibition between these brain regions. Furthermore, our data seem to suggest that the GABA release from astroglia previously observed in the hippocampus and cerebellum occurs via mechanisms other than bestrophin-1.
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Affiliation(s)
- Lasse Ormel
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Knut H Lauritzen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Research Institute of Internal Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Vidar Gundersen
- Section of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Section for Movement Disorders, Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
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17
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Miyagishima KJ, Zhang C, Malechka VV, Bharti K, Li W. Direct-Coupled Electroretinogram (DC-ERG) for Recording the Light-Evoked Electrical Responses of the Mouse Retinal Pigment Epithelium. J Vis Exp 2020. [PMID: 32744516 DOI: 10.3791/61491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The retinal pigment epithelium (RPE) is a specialized monolayer of cells strategically located between the retina and the choriocapillaris that maintain the overall health and structural integrity of the photoreceptors. The RPE is polarized, exhibiting apically and basally located receptors or channels, and performs vectoral transport of water, ions, metabolites, and secretes several cytokines. In vivo noninvasive measurements of RPE function can be made using direct-coupled ERGs (DC-ERGs). The methodology behind the DC-ERG was pioneered by Marmorstein, Peachey, and colleagues using a custom-built stimulation recording system and later demonstrated using a commercially available system. The DC-ERG technique uses glass capillaries filled with Hank's buffered salt solution (HBSS) to measure the slower electrical responses of the RPE elicited from light-evoked concentration changes in the subretinal space due to photoreceptor activity. The prolonged light stimulus and length of the DC-ERG recording make it vulnerable to drift and noise resulting in a low yield of useable recordings. Here, we present a fast, reliable method for improving the stability of the recordings while reducing noise by using vacuum pressure to reduce/eliminate bubbles that result from outgassing of the HBSS and electrode holder. Additionally, power line artifacts are attenuated using a voltage regulator/power conditioner. We include the necessary light stimulation protocols for a commercially available ERG system as well as scripts for analysis of the DC-ERG components: c-wave, fast oscillation, light peak, and off response. Due to the improved ease of recordings and rapid analysis workflow, this simplified protocol is particularly useful in measuring age-related changes in RPE function, disease progression, and in the assessment of pharmacological intervention.
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Affiliation(s)
| | - Congxiao Zhang
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institutes of Health
| | - Volha V Malechka
- Human Visual Function Core, National Eye Institute, National Institutes of Health
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institutes of Health
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health;
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18
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Cross SH, Mckie L, Hurd TW, Riley S, Wills J, Barnard AR, Young F, MacLaren RE, Jackson IJ. The nanophthalmos protein TMEM98 inhibits MYRF self-cleavage and is required for eye size specification. PLoS Genet 2020; 16:e1008583. [PMID: 32236127 PMCID: PMC7153906 DOI: 10.1371/journal.pgen.1008583] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/13/2020] [Accepted: 03/06/2020] [Indexed: 12/31/2022] Open
Abstract
The precise control of eye size is essential for normal vision. TMEM98 is a highly conserved and widely expressed gene which appears to be involved in eye size regulation. Mutations in human TMEM98 are found in patients with nanophthalmos (very small eyes) and variants near the gene are associated in population studies with myopia and increased eye size. As complete loss of function mutations in mouse Tmem98 result in perinatal lethality, we produced mice deficient for Tmem98 in the retinal pigment epithelium (RPE), where Tmem98 is highly expressed. These mice have greatly enlarged eyes that are very fragile with very thin retinas, compressed choroid and thin sclera. To gain insight into the mechanism of action we used a proximity labelling approach to discover interacting proteins and identified MYRF as an interacting partner. Mutations of MYRF are also associated with nanophthalmos. The protein is an endoplasmic reticulum-tethered transcription factor which undergoes autoproteolytic cleavage to liberate the N-terminal part which then translocates to the nucleus where it acts as a transcription factor. We find that TMEM98 inhibits the self-cleavage of MYRF, in a novel regulatory mechanism. In RPE lacking TMEM98, MYRF is ectopically activated and abnormally localised to the nuclei. Our findings highlight the importance of the interplay between TMEM98 and MYRF in determining the size of the eye.
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Affiliation(s)
- Sally H. Cross
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Lisa Mckie
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Toby W. Hurd
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Sam Riley
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Jimi Wills
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Fiona Young
- Electron Microscopy, Pathology, Western General Hospital, Edinburgh, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Ian J. Jackson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
- Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
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19
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Cordes M, Bucichowski P, Alfaar AS, Tsang SH, Almedawar S, Reichhart N, Strauß O. Inhibition of Ca 2+ channel surface expression by mutant bestrophin-1 in RPE cells. FASEB J 2020; 34:4055-4071. [PMID: 31930599 DOI: 10.1096/fj.201901202rr] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 12/09/2019] [Accepted: 12/31/2019] [Indexed: 01/11/2023]
Abstract
The BEST1 gene product bestrophin-1, a Ca2+ -dependent anion channel, interacts with CaV 1.3 Ca2+ channels in the retinal pigment epithelium (RPE). BEST1 mutations lead to Best vitelliform macular dystrophy. A common functional defect of these mutations is reduced trafficking of bestrophin-1 into the plasma membrane. We hypothesized that this defect affects the interaction partner CaV 1.3 channel affecting Ca2+ signaling and altered RPE function. Thus, we investigated the protein interaction between CaV 1.3 channels and bestrophin-1 by immunoprecipitation, CaV 1.3 activity in the presence of mutant bestrophin-1 and intracellular trafficking of the interaction partners in confluent RPE monolayers. We selected four BEST1 mutations, each representing one mutational hotspot of the disease: T6P, F80L, R218C, and F305S. Heterologously expressed L-type channels and mutant bestrophin-1 showed reduced interaction, reduced CaV 1.3 channel activity, and changes in surface expression. Transfection of polarized RPE (porcine primary cells, iPSC-RPE) that endogenously express CaV 1.3 and wild-type bestrophin-1, with mutant bestrophin-1 confirmed reduction of CaV 1.3 surface expression. For the four selected BEST1 mutations, presence of mutant bestrophin-1 led to reduced CaV 1.3 activity by modulating pore-function or decreasing surface expression. Reduced CaV 1.3 activity might open new ways to understand symptoms of Best vitelliform macular dystrophy such as reduced electro-oculogram, lipofuscin accumulation, and vision impairment.
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Affiliation(s)
- Magdalena Cordes
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität, Humboldt-University, the Berlin Institute of Health, Berlin, Germany
| | - Piotr Bucichowski
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität, Humboldt-University, the Berlin Institute of Health, Berlin, Germany
| | - Ahmad S Alfaar
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität, Humboldt-University, the Berlin Institute of Health, Berlin, Germany
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia Stem Cell Initiative, Departments of Ophthalmology Pathology & Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Seba Almedawar
- Center for Molecular and Cellular Bioengineering (CMCB), Center for Regenerative Therapies, Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Nadine Reichhart
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität, Humboldt-University, the Berlin Institute of Health, Berlin, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität, Humboldt-University, the Berlin Institute of Health, Berlin, Germany
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20
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Ji C, Li Y, Kittredge A, Hopiavuori A, Ward N, Yao P, Fukuda Y, Zhang Y, Tsang SH, Yang T. Investigation and Restoration of BEST1 Activity in Patient-derived RPEs with Dominant Mutations. Sci Rep 2019; 9:19026. [PMID: 31836750 PMCID: PMC6910965 DOI: 10.1038/s41598-019-54892-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 11/19/2019] [Indexed: 12/24/2022] Open
Abstract
BEST1 is a Ca2+-activated Cl- channel predominantly expressed in retinal pigment epithelium (RPE), and over 250 genetic mutations in the BEST1 gene have been identified to cause retinal degenerative disorders generally known as bestrophinopathies. As most BEST1 mutations are autosomal dominant, it is of great biomedical interest to determine their disease-causing mechanisms and the therapeutic potential of gene therapy. Here, we characterized six Best vitelliform macular dystrophy (BVMD)-associated BEST1 dominant mutations by documenting the patients' phenotypes, examining the subcellular localization of endogenous BEST1 and surface Ca2+-dependent Cl- currents in patient-derived RPEs, and analyzing the functional influences of these mutations on BEST1 in HEK293 cells. We found that all six mutations are loss-of-function with different levels and types of deficiencies, and further demonstrated the restoration of Ca2+-dependent Cl- currents in patient-derived RPE cells by WT BEST1 gene supplementation. Importantly, BEST1 dominant and recessive mutations are both rescuable at a similar efficacy by gene augmentation via adeno-associated virus (AAV), providing a proof-of-concept for curing the vast majority of bestrophinopathies.
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Affiliation(s)
- Changyi Ji
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA
| | - Yao Li
- Department of Ophthalmology, Columbia University, New York, NY, 10032, USA
| | - Alec Kittredge
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA
| | - Austin Hopiavuori
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA
| | - Nancy Ward
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA
| | - Peng Yao
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, School of Medicine & Dentistry, Rochester, NY, 14586, USA
| | - Yohta Fukuda
- Division of Advance Pharmaco-Science, Graduate School of Pharmaceutical Science, Osaka University, Yamadaoka 1-6, Suita, Osaka, 565-0871, Japan
| | - Yu Zhang
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA.
- Department of Ophthalmology, Columbia University, New York, NY, 10032, USA.
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Edward S. Harkness Eye Institute, Columbia Stem Cell Initiative, New York Presbyterian Hospital/Columbia University, New York, NY, 10032, USA.
| | - Tingting Yang
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, Rochester, NY, 14642, USA.
- Department of Ophthalmology, Columbia University, New York, NY, 10032, USA.
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21
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Ultrasonic Neuromodulation via Astrocytic TRPA1. Curr Biol 2019; 29:3386-3401.e8. [PMID: 31588000 DOI: 10.1016/j.cub.2019.08.021] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/26/2019] [Accepted: 08/08/2019] [Indexed: 01/07/2023]
Abstract
Low-intensity, low-frequency ultrasound (LILFU) is the next-generation, non-invasive brain stimulation technology for treating various neurological and psychiatric disorders. However, the underlying cellular and molecular mechanism of LILFU-induced neuromodulation has remained unknown. Here, we report that LILFU-induced neuromodulation is initiated by opening of TRPA1 channels in astrocytes. The Ca2+ entry through TRPA1 causes a release of gliotransmitters including glutamate through Best1 channels in astrocytes. The released glutamate activates NMDA receptors in neighboring neurons to elicit action potential firing. Our results reveal an unprecedented mechanism of LILFU-induced neuromodulation, involving TRPA1 as a unique sensor for LILFU and glutamate-releasing Best1 as a mediator of glia-neuron interaction. These discoveries should prove to be useful for optimization of human brain stimulation and ultrasonogenetic manipulations of TRPA1.
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22
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Masi A, Narducci R, Mannaioni G. Harnessing ionic mechanisms to achieve disease modification in neurodegenerative disorders. Pharmacol Res 2019; 147:104343. [PMID: 31279830 DOI: 10.1016/j.phrs.2019.104343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/19/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022]
Abstract
Progressive neuronal death is the key pathogenic event leading to clinical symptoms in neurodegenerative disorders (NDDs). Neuroprotective treatments are virtually unavailable, partly because of the marked internal heterogeneity of the mechanisms underlying pathology. Targeted neuroprotection would require deep mechanistic knowledge across the entire aetiological spectrum of each NDD and the development of tailored treatments. Although ideal, this strategy appears challenging, as it would require a degree of characterization of both the disease and the patient that is currently unavailable. The alternate strategy is to search for commonalities across molecularly distinct NDD forms and exploit these for the development of drugs with broad-spectrum efficacy. In this view, mounting evidence points to ionic mechanisms (IMs) as targets with potential therapeutic efficacy across distinct NDD subtypes. The scope of this review is to present clinical and preclinical evidence supporting the link between disruption of IMs and neuronal death in specific NDDs and to critically revise past and ongoing attempts of harnessing IMs for the development of neuroprotective treatments.
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Affiliation(s)
- A Masi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy; School of Pharmacy, University of Camerino, Camerino, Italy.
| | - R Narducci
- Italian Institute of Technology (IIT), Department of Neuroscience and Brain Technologies, Genova, Italy
| | - G Mannaioni
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy; Toxicology Unit, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
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23
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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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24
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Cross SH, Mckie L, Keighren M, West K, Thaung C, Davey T, Soares DC, Sanchez-Pulido L, Jackson IJ. Missense Mutations in the Human Nanophthalmos Gene TMEM98 Cause Retinal Defects in the Mouse. Invest Ophthalmol Vis Sci 2019; 60:2875-2887. [PMID: 31266059 PMCID: PMC6986908 DOI: 10.1167/iovs.18-25954] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose We previously found a dominant mutation, Rwhs, causing white spots on the retina accompanied by retinal folds. Here we identify the mutant gene to be Tmem98. In humans, mutations in the orthologous gene cause nanophthalmos. We modeled these mutations in mice and characterized the mutant eye phenotypes of these and Rwhs. Methods The Rwhs mutation was identified to be a missense mutation in Tmem98 by genetic mapping and sequencing. The human TMEM98 nanophthalmos missense mutations were made in the mouse gene by CRISPR-Cas9. Eyes were examined by indirect ophthalmoscopy and the retinas imaged using a retinal camera. Electroretinography was used to study retinal function. Histology, immunohistochemistry, and electron microscopy techniques were used to study adult eyes. Results An I135T mutation of Tmem98 causes the dominant Rwhs phenotype and is perinatally lethal when homozygous. Two dominant missense mutations of TMEM98, A193P and H196P, are associated with human nanophthalmos. In the mouse these mutations cause recessive retinal defects similar to the Rwhs phenotype, either alone or in combination with each other, but do not cause nanophthalmos. The retinal folds did not affect retinal function as assessed by electroretinography. Within the folds there was accumulation of disorganized outer segment material as demonstrated by immunohistochemistry and electron microscopy, and macrophages had infiltrated into these regions. Conclusions Mutations in the mouse orthologue of the human nanophthalmos gene TMEM98 do not result in small eyes. Rather, there is localized disruption of the laminar structure of the photoreceptors.
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Affiliation(s)
- Sally H. Cross
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Lisa Mckie
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Margaret Keighren
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Katrine West
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Caroline Thaung
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, United Kingdom
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, United Kingdom
| | - Tracey Davey
- Electron Microscopy Research Services, Newcastle University, Newcastle NE2 4HH, United Kingdom
| | - Dinesh C. Soares
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Luis Sanchez-Pulido
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
| | - Ian J. Jackson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, United Kingdom
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25
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Garnai SJ, Brinkmeier ML, Emery B, Aleman TS, Pyle LC, Veleva-Rotse B, Sisk RA, Rozsa FW, Ozel AB, Li JZ, Moroi SE, Archer SM, Lin CM, Sheskey S, Wiinikka-Buesser L, Eadie J, Urquhart JE, Black GC, Othman MI, Boehnke M, Sullivan SA, Skuta GL, Pawar HS, Katz AE, Huryn LA, Hufnagel RB, Camper SA, Richards JE, Prasov L. Variants in myelin regulatory factor (MYRF) cause autosomal dominant and syndromic nanophthalmos in humans and retinal degeneration in mice. PLoS Genet 2019; 15:e1008130. [PMID: 31048900 PMCID: PMC6527243 DOI: 10.1371/journal.pgen.1008130] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/20/2019] [Accepted: 04/09/2019] [Indexed: 01/11/2023] Open
Abstract
Nanophthalmos is a rare, potentially devastating eye condition characterized by small eyes with relatively normal anatomy, a high hyperopic refractive error, and frequent association with angle closure glaucoma and vision loss. The condition constitutes the extreme of hyperopia or farsightedness, a common refractive error that is associated with strabismus and amblyopia in children. NNO1 was the first mapped nanophthalmos locus. We used combined pooled exome sequencing and strong linkage data in the large family used to map this locus to identify a canonical splice site alteration upstream of the last exon of the gene encoding myelin regulatory factor (MYRF c.3376-1G>A), a membrane bound transcription factor that undergoes autoproteolytic cleavage for nuclear localization. This variant produced a stable RNA transcript, leading to a frameshift mutation p.Gly1126Valfs*31 in the C-terminus of the protein. In addition, we identified an early truncating MYRF frameshift mutation, c.769dupC (p.S264QfsX74), in a patient with extreme axial hyperopia and syndromic features. Myrf conditional knockout mice (CKO) developed depigmentation of the retinal pigment epithelium (RPE) and retinal degeneration supporting a role of this gene in retinal and RPE development. Furthermore, we demonstrated the reduced expression of Tmem98, another known nanophthalmos gene, in Myrf CKO mice, and the physical interaction of MYRF with TMEM98. Our study establishes MYRF as a nanophthalmos gene and uncovers a new pathway for eye growth and development.
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Affiliation(s)
- Sarah J. Garnai
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Michelle L. Brinkmeier
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States of America
| | - Ben Emery
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, OR, United States of America
| | - Tomas S. Aleman
- The Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
- Scheie Eye Institute, Department of Ophthalmology, Philadelphia, PA, United States of America
| | - Louise C. Pyle
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States of America
| | - Biliana Veleva-Rotse
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, OR, United States of America
| | - Robert A. Sisk
- Cincinnati Eye Institute, Cincinnati, Ohio, United States of America
| | - Frank W. Rozsa
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
- Molecular and Behavior Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Ayse Bilge Ozel
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States of America
| | - Jun Z. Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States of America
| | - Sayoko E. Moroi
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Steven M. Archer
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Cheng-mao Lin
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Sarah Sheskey
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Laurel Wiinikka-Buesser
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - James Eadie
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Jill E. Urquhart
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, Manchester University NHS Foundation Trust, St Mary’s Hospital, Manchester, United Kingdom
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Graeme C.M. Black
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, Manchester University NHS Foundation Trust, St Mary’s Hospital, Manchester, United Kingdom
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Mohammad I. Othman
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Michael Boehnke
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, United States of America
| | - Scot A. Sullivan
- Dean McGee Eye Institute, Department of Ophthalmology, University of Oklahoma, Oklahoma City, OK
| | - Gregory L. Skuta
- Dean McGee Eye Institute, Department of Ophthalmology, University of Oklahoma, Oklahoma City, OK
| | - Hemant S. Pawar
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
| | - Alexander E. Katz
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Laryssa A. Huryn
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - Robert B. Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | | | - Sally A. Camper
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States of America
| | - Julia E. Richards
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, United States of America
| | - Lev Prasov
- Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI, United States of America
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
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26
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Han YE, Kwon J, Won J, An H, Jang MW, Woo J, Lee JS, Park MG, Yoon BE, Lee SE, Hwang EM, Jung JY, Park H, Oh SJ, Lee CJ. Tweety-homolog ( Ttyh) Family Encodes the Pore-forming Subunits of the Swelling-dependent Volume-regulated Anion Channel (VRAC swell) in the Brain. Exp Neurobiol 2019; 28:183-215. [PMID: 31138989 PMCID: PMC6526117 DOI: 10.5607/en.2019.28.2.183] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 11/19/2022] Open
Abstract
In the brain, a reduction in extracellular osmolality causes water-influx and swelling, which subsequently triggers Cl-- and osmolytes-efflux via volume-regulated anion channel (VRAC). Although LRRC8 family has been recently proposed as the pore-forming VRAC which is activated by low cytoplasmic ionic strength but not by swelling, the molecular identity of the pore-forming swelling-dependent VRAC (VRACswell) remains unclear. Here we identify and characterize Tweety-homologs (TTYH1, TTYH2, TTYH3) as the major VRACswell in astrocytes. Gene-silencing of all Ttyh1/2/3 eliminated hypo-osmotic-solution-induced Cl- conductance (ICl,swell) in cultured and hippocampal astrocytes. When heterologously expressed in HEK293T or CHO-K1 cells, each TTYH isoform showed a significant ICl,swell with similar aquaporin-4 dependency, pharmacological properties and glutamate permeability as ICl,swell observed in native astrocytes. Mutagenesis-based structure-activity analysis revealed that positively charged arginine residue at 165 in TTYH1 and 164 in TTYH2 is critical for the formation of the channel-pore. Our results demonstrate that TTYH family confers the bona fide VRACswell in the brain.
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Affiliation(s)
- Young-Eun Han
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jea Kwon
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Joungha Won
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Heeyoung An
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Minwoo Wendy Jang
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Je Sun Lee
- Molecular Neurobiology Laboratory, Dept. of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu 41068, Korea
| | - Min Gu Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Bo-Eun Yoon
- Department of molecular biology, Dankook University, Cheonan 31116, Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Eun Mi Hwang
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jae-Young Jung
- Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hyungju Park
- Molecular Neurobiology Laboratory, Dept. of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu 41068, Korea
| | - Soo-Jin Oh
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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27
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Wood SR, McClements ME, Martinez-Fernandez de la Camara C, Patrício MI, Uggenti C, Sekaran S, Barnard AR, Manson FD, MacLaren RE. A Quantitative Chloride Channel Conductance Assay for Efficacy Testing of AAV.BEST1. Hum Gene Ther Methods 2019; 30:44-52. [PMID: 30963787 DOI: 10.1089/hgtb.2018.267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mutations in the human BEST1 gene are responsible for a number of distinct retinal disorders known as bestrophinopathies, for which there are no current treatments. The protein product, bestrophin-1, is expressed in the retinal pigment epithelium (RPE) where it localizes to the basolateral membrane and acts as a Ca2+-activated chloride channel. Recent studies have shown successful BEST1-mediated gene transfer to the RPE, indicating human clinical trials of BEST1 gene therapy may be on the horizon. A critical aspect of such trials is the ability to assess the efficacy of vector prior to patient administration. Here, an assay is presented that enables the quantitative assessment of AAV-mediated BEST1 chloride conductance as a measure of vector efficacy. Expression of BEST1 following transduction of HEK293 cells with AAV.BEST1 vectors was confirmed by liquid chromatography, Western blot, and immunocytochemistry. Whole-cell patch-clamp showed increased chloride conductance in BEST1-transduced cells compared to sham-transduced and untransduced controls. Exogenous chloride current correlated to BEST1 expression level, with an enhanced AAV.BEST1.WPRE vector providing higher expression levels of BEST1 and increases in chloride conductance. This study presents in vitro electrophysical quantification of bestrophin-1 following AAV-mediated gene transfer, providing vital functional data on an AAV gene therapy product that will support a future application for regulatory approval.
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Affiliation(s)
- Shaun R Wood
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Michelle E McClements
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | | | - Maria I Patrício
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Carolina Uggenti
- 2 Division of Evolution and Genomic Sciences, The University of Manchester, Manchester, United Kingdom
| | - Sumathi Sekaran
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Alun R Barnard
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Forbes D Manson
- 2 Division of Evolution and Genomic Sciences, The University of Manchester, Manchester, United Kingdom
| | - Robert E MacLaren
- 1 Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,3 National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, United Kingdom.,4 Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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28
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Yu M, Peachey NS. Use of Direct Current Electroretinography for Analysis of Retinal Pigment Epithelium Function in Mouse Models. Methods Mol Biol 2019; 1753:103-113. [PMID: 29564784 DOI: 10.1007/978-1-4939-7720-8_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
A monolayer of pigmented epithelial cells, the retinal pigment epithelium (RPE), supports photoreceptor function in many ways. Consistent with these roles, RPE dysfunction underlies a number of hereditary retinal disorders. To monitor RPE function in vivo models for these conditions, we adapted an electroretinographic (ERG) technique based on direct current amplification (DC-ERG). This chapter describes the main features of this approach and its application to mouse models involving the RPE.
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Affiliation(s)
- Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA. .,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
| | - Neal S Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
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Okada Y, Okada T, Sato-Numata K, Islam MR, Ando-Akatsuka Y, Numata T, Kubo M, Shimizu T, Kurbannazarova RS, Marunaka Y, Sabirov RZ. Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties. Pharmacol Rev 2019; 71:49-88. [PMID: 30573636 DOI: 10.1124/pr.118.015917] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are a number of mammalian anion channel types associated with cell volume changes. These channel types are classified into two groups: volume-activated anion channels (VAACs) and volume-correlated anion channels (VCACs). VAACs can be directly activated by cell swelling and include the volume-sensitive outwardly rectifying anion channel (VSOR), which is also called the volume-regulated anion channel; the maxi-anion channel (MAC or Maxi-Cl); and the voltage-gated anion channel, chloride channel (ClC)-2. VCACs can be facultatively implicated in, although not directly activated by, cell volume changes and include the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, the Ca2+-activated Cl- channel (CaCC), and the acid-sensitive (or acid-stimulated) outwardly rectifying anion channel. This article describes the phenotypical properties and activation mechanisms of both groups of anion channels, including accumulating pieces of information on the basis of recent molecular understanding. To that end, this review also highlights the molecular identities of both anion channel groups; in addition to the molecular identities of ClC-2 and CFTR, those of CaCC, VSOR, and Maxi-Cl were recently identified by applying genome-wide approaches. In the last section of this review, the most up-to-date information on the pharmacological properties of both anion channel groups, especially their half-maximal inhibitory concentrations (IC50 values) and voltage-dependent blocking, is summarized particularly from the standpoint of pharmacological distinctions among them. Future physiologic and pharmacological studies are definitely warranted for therapeutic targeting of dysfunction of VAACs and VCACs.
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Affiliation(s)
- Yasunobu Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Toshiaki Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Kaori Sato-Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Md Rafiqul Islam
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yuhko Ando-Akatsuka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Tomohiro Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Machiko Kubo
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Takahiro Shimizu
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ranohon S Kurbannazarova
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yoshinori Marunaka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ravshan Z Sabirov
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
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Dalvi S, Galloway CA, Singh R. Pluripotent Stem Cells to Model Degenerative Retinal Diseases: The RPE Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1186:1-31. [PMID: 31654384 DOI: 10.1007/978-3-030-28471-8_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pluripotent stem cell technology, including human-induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs), has provided a suitable platform to investigate molecular and pathological alterations in an individual cell type using patient's own cells. Importantly, hiPSCs/hESCs are amenable to genome editing providing unique access to isogenic controls. Specifically, the ability to introduce disease-causing mutations in control (unaffected) and conversely correct disease-causing mutations in patient-derived hiPSCs has provided a powerful approach to clearly link the disease phenotype with a specific gene mutation. In fact, utilizing hiPSC/hESC and CRISPR technology has provided significant insight into the pathomechanism of several diseases. With regard to the eye, the use of hiPSCs/hESCs to study human retinal diseases is especially relevant to retinal pigment epithelium (RPE)-based disorders. This is because several studies have now consistently shown that hiPSC-RPE in culture displays key physical, gene expression and functional attributes of human RPE in vivo. In this book chapter, we will discuss the current utility, limitations, and plausible future approaches of pluripotent stem cell technology for the study of retinal degenerative diseases. Of note, although we will broadly summarize the significant advances made in modeling and studying several retinal diseases utilizing hiPSCs/hESCs, our specific focus will be on the utility of patient-derived hiPSCs for (1) establishment of human cell models and (2) molecular and pharmacological studies on patient-derived cell models of retinal degenerative diseases where RPE cellular defects play a major pathogenic role in disease development and progression.
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Affiliation(s)
- Sonal Dalvi
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Department of Biomedical Genetics, University of Rochester, Rochester, NY, USA
| | - Chad A Galloway
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY, USA.,Department of Biomedical Genetics, University of Rochester, Rochester, NY, USA
| | - Ruchira Singh
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY, USA. .,Department of Biomedical Genetics, University of Rochester, Rochester, NY, USA. .,UR Stem Cell and Regenerative Medicine Institute, Rochester, NY, USA. .,Center for Visual Science, University of Rochester, Rochester, NY, USA.
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Clinical and Mutation Analysis of Patients with Best Vitelliform Macular Dystrophy or Autosomal Recessive Bestrophinopathy in Chinese Population. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4582816. [PMID: 30498755 PMCID: PMC6220750 DOI: 10.1155/2018/4582816] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/21/2018] [Accepted: 09/19/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the gene BEST1 usually cause bestrophinopathies, such as the rare progressive diseases Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB). This study aimed to investigate the clinical characteristics of patients with BVMD or ARB carrying BEST1 mutations. A total of 12 probands including 9 patients with a clinical diagnosis of BVMD and 3 patients with a clinical diagnosis of ARB were recruited for genetics analysis. All patients underwent detailed ophthalmic examination. All coding exons of the BEST1 gene were screened by PCR-based DNA sequencing. Programs of PolyPhen-2, SIFT, and MutationTaster were used to analyze the potential pathogenicity of the mutations in BEST1. In the 9 unrelated patients with BVMD, one heterozygous BEST1 mutation was revealed in 8 patients and two compound heterozygous mutations in 1 patient. In the 3 unrelated patients with ARB, two compound heterozygous mutations were revealed in 2 patients and three compound heterozygous mutations in 1 patient. Molecular analyses identified a total of 15 mutations, including 3 novel mutations (c.424A>G p.S142G, c.436G>A p.A146T, and c.155T>C p.L52P). Antivascular endothelial growth factor (VEGF) drugs were given to two affected eyes, especially those also exhibiting choroidal neovascularization (CNV), and no serious adverse events occurred. Our study indicates that there is wide genotypic and phenotypic variability in patients with BVMD or ARB in China. The screening of BEST1 gene is significant for the precise diagnosis of BVMD and ARB.
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Cao X, Pattnaik BR, Hughes BA. Mouse retinal pigment epithelial cells exhibit a thiocyanate-selective conductance. Am J Physiol Cell Physiol 2018; 315:C457-C473. [PMID: 29874109 DOI: 10.1152/ajpcell.00231.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The basolateral membrane anion conductance of the retinal pigment epithelium (RPE) is a key component of the transepithelial Cl- transport pathway. Although multiple Cl- channels have been found to be expressed in the RPE, the components of the resting Cl- conductance have not been identified. In this study, we used the patch-clamp method to characterize the ion selectivity of the anion conductance in isolated mouse RPE cells and in excised patches of RPE basolateral and apical membranes. Relative permeabilities ( PA/ PCl) calculated from reversal potentials measured in intact cells under bi-ionic conditions were as follows: SCN- >> ClO4- > [Formula: see text] > I- > Br- > Cl- >> gluconate. Relative conductances ( GA/ GCl) followed a similar trend of SCN- >> ClO4- > [Formula: see text] > I- > Br- ≈Cl- >> gluconate. Whole cell currents were highly time-dependent in 10 mM external SCN-, reflecting collapse of the electrochemical potential gradient due to SCN- accumulation or depletion intracellularly. When the membrane potential was held at -120 mV to minimize SCN- accumulation in cells exposed to 10 mM SCN-, the instantaneous current reversed at -90 mV, revealing that PSCN/ PCl is approximately 500. Macroscopic current recordings from outside-out patches demonstrated that both the basolateral and apical membranes exhibit SCN- conductances, with the basolateral membrane having a larger SCN- current density and higher relative permeability for SCN-. Our results suggest that the RPE basolateral and apical membranes contain previously unappreciated anion channels or electrogenic transporters that may mediate the transmembrane fluxes of SCN- and Cl-.
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Affiliation(s)
- Xu Cao
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan
| | - Bikash R Pattnaik
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan
| | - Bret A Hughes
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan.,Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
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Tsai YT, Wu WH, Lee TT, Wu WP, Xu CL, Park KS, Cui X, Justus S, Lin CS, Jauregui R, Su PY, Tsang SH. Clustered Regularly Interspaced Short Palindromic Repeats-Based Genome Surgery for the Treatment of Autosomal Dominant Retinitis Pigmentosa. Ophthalmology 2018; 125:1421-1430. [PMID: 29759820 PMCID: PMC6109419 DOI: 10.1016/j.ophtha.2018.04.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/29/2018] [Accepted: 04/02/2018] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To develop a universal gene therapy to overcome the genetic heterogeneity in retinitis pigmentosa (RP) resulting from mutations in rhodopsin (RHO). DESIGN Experimental study for a combination gene therapy that uses both gene ablation and gene replacement. PARTICIPANTS This study included 2 kinds of human RHO mutation knock-in mouse models: RhoP23H and RhoD190N. In total, 23 RhoP23H/P23H, 43 RhoP23H/+, and 31 RhoD190N/+ mice were used for analysis. METHODS This study involved gene therapy using dual adeno-associated viruses (AAVs) that (1) destroy expression of the endogenous Rho gene in a mutation-independent manner via an improved clustered regularly interspaced short palindromic repeats-based gene deletion and (2) enable expression of wild-type protein via exogenous cDNA. MAIN OUTCOME MEASURES Electroretinographic and histologic analysis. RESULTS The thickness of the outer nuclear layer (ONL) after the subretinal injection of combination ablate-and-replace gene therapy was approximately 17% to 36% more than the ONL thickness resulting from gene replacement-only therapy at 3 months after AAV injection. Furthermore, electroretinography results demonstrated that the a and b waves of both RhoP23H and RhoD190N disease models were preserved more significantly using ablate-and-replace gene therapy (P < 0.001), but not by gene replacement monotherapy. CONCLUSIONS As a proof of concept, our results suggest that the ablate-and-replace strategy can ameliorate disease progression as measured by photoreceptor structure and function for both of the human mutation knock-in models. These results demonstrate the potency of the ablate-and-replace strategy to treat RP caused by different Rho mutations. Furthermore, because ablate-and-replace treatment is mutation independent, this strategy may be used to treat a wide array of dominant diseases in ophthalmology and other fields. Clinical trials using ablate-and-replace gene therapy would allow researchers to determine if this strategy provides any benefits for patients with diseases of interest.
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Affiliation(s)
- Yi-Ting Tsai
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Ting-Ting Lee
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Wei-Pu Wu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Christine L Xu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Karen S Park
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Sally Justus
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Chyuan-Sheng Lin
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York
| | - Ruben Jauregui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Weill Cornell Medical College, New York, New York
| | - Pei-Yin Su
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, New York; Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York; Department of Ophthalmology, Edward S. Harkness Eye Institute, New York Presbyterian Hospital, New York, New York.
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Kittredge A, Ji C, Zhang Y, Yang T. Differentiation, Maintenance, and Analysis of Human Retinal Pigment Epithelium Cells: A Disease-in-a-dish Model for BEST1 Mutations. J Vis Exp 2018. [PMID: 30199040 DOI: 10.3791/57791] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Although over 200 genetic mutations in the human BEST1 gene have been identified and linked to retinal degenerative diseases, the pathological mechanisms remain elusive mainly due to the lack of a good in vivo model for studying BEST1 and its mutations under physiological conditions. BEST1 encodes an ion channel, namely BESTROPHIN1 (BEST1), which functions in retinal pigment epithelium (RPE); however, the extremely limited accessibility to native human RPE cells represents a major challenge for scientific research. This protocol describes how to generate human RPEs bearing BEST1 disease-causing mutations by induced differentiation from human pluripotent stem cells (hPSCs). As hPSCs are self-renewable, this approach allows researchers to have a steady source of hPSC-RPEs for various experimental analyses, such as immunoblotting, immunofluorescence, and patch clamp, and thus provides a very powerful disease-in-a-dish model for BEST1-associated retinal conditions. Notably, this strategy can be applied to study RPE (patho)physiology and other genes of interest natively expressed in RPE.
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Affiliation(s)
- Alec Kittredge
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry
| | - Changyi Ji
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry
| | - Yu Zhang
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry;
| | - Tingting Yang
- Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry;
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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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Li Y, Zhang Y, Xu Y, Kittredge A, Ward N, Chen S, Tsang SH, Yang T. Patient-specific mutations impair BESTROPHIN1's essential role in mediating Ca 2+-dependent Cl - currents in human RPE. eLife 2017; 6. [PMID: 29063836 PMCID: PMC5655127 DOI: 10.7554/elife.29914] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/13/2017] [Indexed: 01/06/2023] Open
Abstract
Mutations in the human BEST1 gene lead to retinal degenerative diseases displaying progressive vision loss and even blindness. BESTROPHIN1, encoded by BEST1, is predominantly expressed in retinal pigment epithelium (RPE), but its physiological role has been a mystery for the last two decades. Using a patient-specific iPSC-based disease model and interdisciplinary approaches, we comprehensively analyzed two distinct BEST1 patient mutations, and discovered mechanistic correlations between patient clinical phenotypes, electrophysiology in their RPEs, and the structure and function of BESTROPHIN1 mutant channels. Our results revealed that the disease-causing mechanism of BEST1 mutations is centered on the indispensable role of BESTROPHIN1 in mediating the long speculated Ca2+-dependent Cl- current in RPE, and demonstrate that the pathological potential of BEST1 mutations can be evaluated and predicted with our iPSC-based 'disease-in-a-dish' approach. Moreover, we demonstrated that patient RPE is rescuable with viral gene supplementation, providing a proof-of-concept for curing BEST1-associated diseases.
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Affiliation(s)
- Yao Li
- Jonas Children's Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology and Pathology & Cell Biology, Edward S. Harkness Eye Institute, New York Presbyterian Hospital/Columbia University, New York, United States
| | - Yu Zhang
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Yu Xu
- Jonas Children's Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology and Pathology & Cell Biology, Edward S. Harkness Eye Institute, New York Presbyterian Hospital/Columbia University, New York, United States.,Department of Ophthalmology, Xinhua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Alec Kittredge
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Nancy Ward
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Shoudeng Chen
- Molecular Imaging Center, Department of Experimental Medicine, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology and Pathology & Cell Biology, Edward S. Harkness Eye Institute, New York Presbyterian Hospital/Columbia University, New York, United States
| | - Tingting Yang
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
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Oh SJ, Lee CJ. Distribution and Function of the Bestrophin-1 (Best1) Channel in the Brain. Exp Neurobiol 2017; 26:113-121. [PMID: 28680296 PMCID: PMC5491579 DOI: 10.5607/en.2017.26.3.113] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 12/29/2022] Open
Abstract
Bestrophin-1 (Best1) is a calcium-activated anion channel identified from retinal pigment epithelium where human mutations are associated with Best's macular degeneration. Best1 is known to be expressed in a variety of tissues including the brain, and is thought to be involved in many physiological processes. This review focuses on the current state of knowledge on aspects of expression and function of Best1 in the brain. Best1 protein is observed in cortical and hippocampal astrocytes, in cerebellar Bergmann glia and lamellar astrocytes, in thalamic reticular neurons, in meninges and in the epithelial cells of the choroid plexus. The most prominent feature of Best1 is its significant permeability to glutamate and GABA in addition to chloride ions because glutamate and GABA are important transmitters in the brain. Under physiological conditions, both Best1-mediated glutamate release and tonic GABA release from astrocytes modulate neuronal excitability, synaptic transmission and synaptic plasticity. Under pathological conditions such as neuroinflammation and neurodegeneration, reactive astrocytes phenotypically switch from GABA-negative to GABA-producing and redistribute Best1 from the perisynaptic microdomains to the soma and processes to tonically release GABA via Best1. This implicates that tonic GABA release from reactive astrocyte via redistributed Best1 is a common phenomenon that occur in various pathological conditions with astrogliosis such as traumatic brain injury, neuroinflammation, neurodegeneration, and hypoxic and ischemic insults. These properties of Best1, including the permeation and release of glutamate and GABA and its redistribution in reactive astrocytes, promise us exciting discoveries of novel brain functions to be uncovered in the future.
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Affiliation(s)
- Soo-Jin Oh
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - C Justin Lee
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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Tarchick MJ, Bassiri P, Rohwer RM, Samuels IS. Early Functional and Morphologic Abnormalities in the Diabetic Nyxnob Mouse Retina. Invest Ophthalmol Vis Sci 2017; 57:3496-508. [PMID: 27367517 PMCID: PMC4961059 DOI: 10.1167/iovs.15-18775] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose The electroretinogram c-wave is generated by the summation of the positive polarity hyperpolarization of the apical RPE membrane and a negative polarity slow PIII response of Müller glia cells. Therefore, the c-wave reduction noted in prior studies of mouse models of diabetes could reflect a reduction in the RPE component or an increase in slow PIII. The present study used a genetic approach to distinguish between these two alternatives. Methods Nyxnob mice lack the ERG b-wave, revealing the early phase of slow PIII. To visualize changes in slow PIII due to diabetes, Nyxnob mice were given streptozotocin (STZ) injections to induce diabetes or received vehicle as a control. After 1, 2, and 4 weeks of sustained hyperglycemia (>250 mg/dL), standard strobe flash ERG and dc-ERG testing were conducted. Histological analysis of the retina was performed. Results A reduced c-wave was noted at the 1 week time point, and persisted at later time points. In comparison, slow PIII amplitudes were unaffected after 1 week of hyperglycemia, but were significantly reduced in STZ mice at the 2-week time point. The decrease in amplitude occurred before any identifiable decrease to the a-wave. At the later time point, the a-wave became involved, although the slow PIII reductions were more pronounced. Morphological abnormalities in the RPE, including increased thickness and altered melanosome distribution, were identified in diabetic animals. Conclusions Because the c-wave and slow PIII were both reduced, these results demonstrated that diabetes-induced reductions to the c-wave cannot be attributed to an early increase in the Müller glia-derived potassium conductance. Furthermore, because the a-wave, slow PIII and c-wave reductions were not equivalent, and varied in their onset, the reductions cannot reflect the same mechanism, such as a change in membrane resistance. The presence of small changes to RPE architecture indicate that the c-wave reductions present in diabetic mice likely represents a primary change in the RPE induced by hyperglycemia.
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Affiliation(s)
- Matthew J Tarchick
- Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States 2Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Parastoo Bassiri
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Rebecca M Rohwer
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Ivy S Samuels
- Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States 2Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
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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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Keckeis S, Reichhart N, Roubeix C, Strauß O. Anoctamin2 (TMEM16B) forms the Ca2+-activated Cl− channel in the retinal pigment epithelium. Exp Eye Res 2017; 154:139-150. [DOI: 10.1016/j.exer.2016.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 01/12/2023]
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41
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Schreiber R, Kunzelmann K. Expression of anoctamins in retinal pigment epithelium (RPE). Pflugers Arch 2016; 468:1921-1929. [PMID: 27822608 DOI: 10.1007/s00424-016-1898-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/17/2016] [Accepted: 10/19/2016] [Indexed: 01/24/2023]
Abstract
The anoctamin (ANO, TMEM16) family of Ca2+-activated Cl- channels consists of ten members with different cellular functions (ANO1-10). ANO1 is a Ca2+-activated Cl- channel in secretory epithelial cells of exocrine pancreas, salivary glands, or enterocytes. Expression of ANO1 also promotes cell proliferation and migration of tumor cells. ANO6 is essential for Ca2+-dependent scrambling of membrane phospholipids in platelets, red blood cells, and lymphocytes. ANO10 modulates Ca2+ signals in macrophages and has a role in cerebellar ataxia and other neurological disorders. All three anoctamins have been proposed to control intracellular Ca2+ signals. Anoctamins may also form the basolateral Ca2+-activated Cl- channel in the retinal pigment epithelium (RPE). We show that native human, bovine, porcine, and mouse RPEs express ANO1, ANO6, and ANO10. Growth arrested and confluent RPR cells expressed ANO1 in the plasma membrane, whereas ANO6 and ANO10 were found in the primary cilium. Ussing chamber experiments showed that the application of ATP to the apical (retinal) side of porcine RPE induced a Ca2+-activated Cl- secretion. Activation was inhibited by basolateral (choroidal) administration of the ANO inhibitors AO1, niflumic acid (NFA), and 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS). The results suggest that ANO1 is responsible for basolateral Ca2+-dependent Cl- secretion in RPE, whereas ANO6 and ANO10 may have different functions, such as modulating Ca2+ signals.
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Affiliation(s)
- Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
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42
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Effects of Ca 2+ ions on bestrophin-1 surface films. Colloids Surf B Biointerfaces 2016; 149:226-232. [PMID: 27768912 DOI: 10.1016/j.colsurfb.2016.10.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/07/2016] [Accepted: 10/12/2016] [Indexed: 01/01/2023]
Abstract
Human bestrophin-1 (hBest1) is a transmembrane calcium-activated chloride channel protein - member of the bestrophin family of anion channels, predominantly expressed in the membrane of retinal pigment epithelium (RPE) cells. Mutations in the protein cause ocular diseases, named Bestrophinopathies. Here, we present the first Fourier transform infrared (FTIR) study of the secondary structure elements of hBest1, π/A isotherms and hysteresis, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) visualization of the aggregation state of protein molecules dispersed as Langmuir and Langmuir-Blodgett films. The secondary structure of hBest1 consists predominantly of 310-helices (27.2%), α-helixes (16.3%), β-turns and loops (32.2%). AFM images of hBest1 suggest approximate lateral dimensions of 100×160Å and 75Å height. Binding of calcium ions (Ca2+) induces conformational changes in the protein secondary structure leading to assembly of protein molecules and changes in molecular and macro-organization of hBest1 in monolayers. These data provide basic information needed in pursuit of molecular mechanisms underlying retinal and other pathologies linked to this protein.
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Mislocalisation of BEST1 in iPSC-derived retinal pigment epithelial cells from a family with autosomal dominant vitreoretinochoroidopathy (ADVIRC). Sci Rep 2016; 6:33792. [PMID: 27653836 PMCID: PMC5031956 DOI: 10.1038/srep33792] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/26/2016] [Indexed: 12/31/2022] Open
Abstract
Autosomal dominant vitreoretinochoroidopathy (ADVIRC) is a rare, early-onset retinal dystrophy characterised by distinct bands of circumferential pigmentary degeneration in the peripheral retina and developmental eye defects. ADVIRC is caused by mutations in the Bestrophin1 (BEST1) gene, which encodes a transmembrane protein thought to function as an ion channel in the basolateral membrane of retinal pigment epithelial (RPE) cells. Previous studies suggest that the distinct ADVIRC phenotype results from alternative splicing of BEST1 pre-mRNA. Here, we have used induced pluripotent stem cell (iPSC) technology to investigate the effects of an ADVIRC associated BEST1 mutation (c.704T > C, p.V235A) in patient-derived iPSC-RPE. We found no evidence of alternate splicing of the BEST1 transcript in ADVIRC iPSC-RPE, however in patient-derived iPSC-RPE, BEST1 was expressed at the basolateral membrane and the apical membrane. During human eye development we show that BEST1 is expressed more abundantly in peripheral RPE compared to central RPE and is also expressed in cells of the developing retina. These results suggest that higher levels of mislocalised BEST1 expression in the periphery, from an early developmental stage, could provide a mechanism that leads to the distinct clinical phenotype observed in ADVIRC patients.
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Moshfegh Y, Velez G, Li Y, Bassuk AG, Mahajan VB, Tsang SH. BESTROPHIN1 mutations cause defective chloride conductance in patient stem cell-derived RPE. Hum Mol Genet 2016; 25:2672-2680. [PMID: 27193166 DOI: 10.1093/hmg/ddw126] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/13/2016] [Accepted: 04/18/2016] [Indexed: 12/20/2022] Open
Abstract
Bestrophin1 (BEST1) is expressed in human retinal pigment epithelium (RPE) and mutations in the BEST1 gene commonly cause retinal dysfunction and macular degeneration. BEST1 is presumed to assemble into a calcium-activated chloride channel and be involved in chloride transport but there is no direct evidence in live human RPE cells to support this idea. To test whether BEST1 functions as a chloride channel in living tissue, BEST1-mutant RPE (R218H, L234P, A243T) were generated from patient-derived induced pluripotent stem cells and compared with wild-type RPE in a retinal environment, using a biosensor that visualizes calcium-induced chloride ion flux in the cell. Calcium stimulation elicited chloride ion export in normal RPE but not in RPE derived from three patients with BEST1 mutations. These data, along with three-dimensional modeling, provide evidence that BEST1 assembles into a key calcium-sensing chloride channel in human RPE.
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Affiliation(s)
- Yasmin Moshfegh
- Barbara & Donald Jonas Laboratory of Regenerative Medicine, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Pathology & Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | - Gabriel Velez
- Omics Lab.,Department of Ophthalmology and Visual Sciences.,Medical Scientist Training Program
| | - Yao Li
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
| | | | - Vinit B Mahajan
- Department of Ophthalmology and Visual Sciences.,Medical Scientist Training Program
| | - Stephen H Tsang
- Barbara & Donald Jonas Laboratory of Regenerative Medicine, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Pathology & Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA .,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY 10032, USA
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45
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Dalvin LA, Abou Chehade JE, Chiang J, Fuchs J, Iezzi R, Marmorstein AD. Retinitis pigmentosa associated with a mutation in BEST1. Am J Ophthalmol Case Rep 2016; 2:11-17. [PMID: 29503890 PMCID: PMC5757359 DOI: 10.1016/j.ajoc.2016.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 03/18/2016] [Accepted: 03/26/2016] [Indexed: 11/24/2022] Open
Abstract
Purpose There is only one prior report associating mutations in BEST1 with a diagnosis of retinitis pigmentosa (RP). The imaging studies presented in that report were more atypical of RP and shared features of autosomal recessive bestrophinopathy and autosomal dominant vitreoretinochoroidopathy. Here, we present a patient with a clinical phenotype consistent with classic features of RP. Observations The patient in this report was diagnosed with simplex RP based on clinically-evident bone spicules with characteristic ERG and EOG findings. The patient had associated massive cystoid macular edema which resolved following a short course of oral acetazolamide. Genetic testing revealed that the patient carries a novel heterozygous deletion mutation in BEST1 which is not carried by either parent. While this suggests BEST1 is causative, the patient also inherited heterozygous copies of several mutations in other genes known to cause recessive retinal degenerative disease. Conclusions and Importance How some mutations in BEST1 associate with peripheral retinal degeneration phenotypes, while others manifest as macular degeneration phenotypes is currently unknown. We speculate that RP due to BEST1 mutation requires mutations in other modifier genes.
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Affiliation(s)
- Lauren A Dalvin
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States
| | - Jackson E Abou Chehade
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States
| | - John Chiang
- CEI Diagnostic Laboratory, Casey Eye Institute, 3375 SW Terwilliger Blvd, Portland, OR, 97239, United States
| | - Josefine Fuchs
- Department of Ophthalmology, Rigshospitalet, Blegdamsvej 9, 2100, København Ø, Denmark
| | - Raymond Iezzi
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States
| | - Alan D Marmorstein
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, United States
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Giblin JP, Comes N, Strauss O, Gasull X. Ion Channels in the Eye: Involvement in Ocular Pathologies. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:157-231. [PMID: 27038375 DOI: 10.1016/bs.apcsb.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The eye is the sensory organ of vision. There, the retina transforms photons into electrical signals that are sent to higher brain areas to produce visual sensations. In the light path to the retina, different types of cells and tissues are involved in maintaining the transparency of avascular structures like the cornea or lens, while others, like the retinal pigment epithelium, have a critical role in the maintenance of photoreceptor function by regenerating the visual pigment. Here, we have reviewed the roles of different ion channels expressed in ocular tissues (cornea, conjunctiva and neurons innervating the ocular surface, lens, retina, retinal pigment epithelium, and the inflow and outflow systems of the aqueous humor) that are involved in ocular disease pathophysiologies and those whose deletion or pharmacological modulation leads to specific diseases of the eye. These include pathologies such as retinitis pigmentosa, macular degeneration, achromatopsia, glaucoma, cataracts, dry eye, or keratoconjunctivitis among others. Several disease-associated ion channels are potential targets for pharmacological intervention or other therapeutic approaches, thus highlighting the importance of these channels in ocular physiology and pathophysiology.
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Affiliation(s)
- Jonathan P Giblin
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Nuria Comes
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Xavier Gasull
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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Giordano CR, Roberts R, Krentz KA, Bissig D, Talreja D, Kumar A, Terlecky SR, Berkowitz BA. Catalase therapy corrects oxidative stress-induced pathophysiology in incipient diabetic retinopathy. Invest Ophthalmol Vis Sci 2015; 56:3095-102. [PMID: 25813998 DOI: 10.1167/iovs.14-16194] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
PURPOSE Preclinical studies have highlighted retinal oxidative stress in the pathogenesis of diabetic retinopathy. We evaluated whether a treatment designed to enhance cellular catalase reduces oxidative stress in retinal cells cultured in high glucose and in diabetic mice corrects an imaging biomarker responsive to antioxidant therapy (manganese-enhanced magnetic resonance imaging [MEMRI]). METHODS Human retinal Müller and pigment epithelial cells were chronically exposed to normal or high glucose levels and treated with a cell-penetrating derivative of the peroxisomal enzyme catalase (called CAT-SKL). Hydrogen peroxide (H2O2) levels were measured using a quantitative fluorescence-based assay. For in vivo studies, streptozotocin (STZ)-induced diabetic C57Bl/6 mice were treated subcutaneously once a week for 3 to 4 months with CAT-SKL; untreated age-matched nondiabetic controls and untreated diabetic mice also were studied. MEMRI was used to analytically assess the efficacy of CAT-SKL treatment on diabetes-evoked oxidative stress-related pathophysiology in vivo. Similar analyses were performed with difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase. RESULTS After catalase transduction, high glucose-induced peroxide production was significantly lowered in both human retinal cell lines. In diabetic mice in vivo, subnormal intraretinal uptake of manganese was significantly improved by catalase supplementation. In addition, in the peroxisome-rich liver of treated mice catalase enzyme activity increased and oxidative damage (as measured by lipid peroxidation) declined. On the other hand, DFMO was largely without effect in these in vitro or in vivo assays. CONCLUSIONS This proof-of-concept study raises the possibility that augmentation of catalase is a therapy for treating the retinal oxidative stress associated with diabetic retinopathy.
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Affiliation(s)
- Courtney R Giordano
- Department of Pharmacology, Wayne State University, Detroit, Michigan, United States
| | - Robin Roberts
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States
| | - Kendra A Krentz
- Department of Pharmacology, Wayne State University, Detroit, Michigan, United States
| | - David Bissig
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States
| | - Deepa Talreja
- Department of Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - Ashok Kumar
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States 3Department of Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - Stanley R Terlecky
- Department of Pharmacology, Wayne State University, Detroit, Michigan, United States
| | - Bruce A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States 3Department of Ophthalmology, Wayne State University, Detroit, Michigan, United States
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48
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Johnson AA, Bachman LA, Gilles BJ, Cross SD, Stelzig KE, Resch ZT, Marmorstein LY, Pulido JS, Marmorstein AD. Autosomal Recessive Bestrophinopathy Is Not Associated With the Loss of Bestrophin-1 Anion Channel Function in a Patient With a Novel BEST1 Mutation. Invest Ophthalmol Vis Sci 2015. [PMID: 26200502 DOI: 10.1167/iovs.15-16910] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
PURPOSE Mutations in BEST1, encoding bestrophin-1 (Best1), cause autosomal recessive bestrophinopathy (ARB). Encoding bestrophin-1 is a pentameric anion channel localized to the basolateral plasma membrane of the RPE. Here, we characterize the effects of the mutations R141H (CGC > CAC) and I366fsX18 (c.1098_1100+7del), identified in a patient in our practice, on Best1 trafficking, oligomerization, and channel activity. METHODS Currents of Cl- were assessed in transfected HEK293 cells using whole-cell patch clamp. Best1 localization was assessed by confocal microscopy in differentiated, human-induced pluripotent stem cell-derived RPE (iPSC-RPE) cells following expression of mutants via adenovirus-mediated gene transfer. Oligomerization was evaluated by coimmunoprecipitation in iPSC-RPE and MDCK cells. RESULTS Compared to Best1, Best1 I366fsX18 currents were increased while Best1 R141H Cl- currents were diminished. Coexpression of Best1 R141H with Best1 or Best1 I366fsX18 resulted in rescued channel activity. Overexpressed Best1, Best1 R141H, and Best1 I366fsX18 were all properly localized in iPSC-RPE cells; Best1 R141H and Best1 I366fsX18 coimmunoprecipitated with endogenous Best1 in iPSC-RPE cells and with each other in MDCK cells. CONCLUSIONS The first 366 amino acids of Best1 are sufficient to mediate channel activity and homo-oligomerization. The combination of Best1 and Best1 R141H does not cause disease, while Best1 R141H together with Best1 I366fsX18 causes ARB. Since both combinations generate comparable Cl- currents, this indicates that ARB in this patient is not caused by a loss of channel activity. Moreover, Best1 I366fsX18 differs from Best1 in that it lacks most of the cytosolic C-terminal domain, suggesting that the loss of this region contributes significantly to the pathogenesis of ARB in this patient.
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Affiliation(s)
- Adiv A Johnson
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
| | - Lori A Bachman
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
| | - Benjamin J Gilles
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
| | - Samuel D Cross
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
| | - Kimberly E Stelzig
- Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Zachary T Resch
- Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Lihua Y Marmorstein
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
| | - Jose S Pulido
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States 3Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Alan D Marmorstein
- Department of Ophthalmology Mayo Clinic, Rochester, Minnesota, United States
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Bestrophin 1 is indispensable for volume regulation in human retinal pigment epithelium cells. Proc Natl Acad Sci U S A 2015; 112:E2630-9. [PMID: 25941382 DOI: 10.1073/pnas.1418840112] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In response to cell swelling, volume-regulated anion channels (VRACs) participate in a process known as regulatory volume decrease (RVD). Only recently, first insight into the molecular identity of mammalian VRACs was obtained by the discovery of the leucine-rich repeats containing 8A (LRRC8A) gene. Here, we show that bestrophin 1 (BEST1) but not LRRC8A is crucial for volume regulation in human retinal pigment epithelium (RPE) cells. Whole-cell patch-clamp recordings in RPE derived from human-induced pluripotent stem cells (hiPSC) exhibit an outwardly rectifying chloride current with characteristic functional properties of VRACs. This current is severely reduced in hiPSC-RPE cells derived from macular dystrophy patients with pathologic BEST1 mutations. Disruption of the orthologous mouse gene (Best1(-/-)) does not result in obvious retinal pathology but leads to a severe subfertility phenotype in agreement with minor endogenous expression of Best1 in murine RPE but highly abundant expression in mouse testis. Sperm from Best1(-/-) mice showed reduced motility and abnormal sperm morphology, indicating an inability in RVD. Together, our data suggest that the molecular identity of VRACs is more complex--that is, instead of a single ubiquitous channel, VRACs could be formed by cell type- or tissue-specific subunit composition. Our findings provide the basis to further examine VRAC diversity in normal and diseased cell physiology, which is key to exploring novel therapeutic approaches in VRAC-associated pathologies.
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