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Nipp GE, Sarici K, Lee T, Hadziahmetovic M. Risk Factors for Worsening Morphology and Visual Acuity in Eyes with Adult-Onset Foveomacular Vitelliform Dystrophy. Ophthalmol Retina 2024; 8:804-812. [PMID: 38461930 DOI: 10.1016/j.oret.2024.03.004] [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: 10/18/2023] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 03/12/2024]
Abstract
PURPOSE To explore clinical risk factors and OCT features associated with worse visual acuity (VA), progression of disease, choroidal neovascularization (CNV), and atrophy in eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD). DESIGN Single-center, retrospective, observational cohort study. PARTICIPANTS Patients seen at Duke Eye Center between January 2012 and May 2023 with a diagnosis of AOFVD confirmed via OCT and fundus autofluorescence. METHODS Baseline and final-visit images from eyes with AOFVD were examined. Disease stage was assigned, and presence of atrophy or CNV was determined. Clinical and OCT features associated with progression to atrophy and CNV were determined using t tests and chi-square analysis. Correlation with lower VA was determined using linear regression. MAIN OUTCOME MEASURES Association of clinical characteristics and OCT features with worse VA, progression of disease, CNV, and atrophy as determined by independent t tests, chi-square analysis, and linear regression (P < 0.05). RESULTS One hundred one eyes (63 patients) met inclusion criteria for this study, with mean follow-up duration of 48 months (standard deviation, 31 months). Fifty-one percent of eyes progressed beyond baseline staging during follow-up; among baseline stage 1 eyes, incidence of atrophy was 0.068/person-year; incidence of CNV was 0.022/person-year. Risk factors for worse final VA were baseline presence of vitreomacular traction ([VMT], P = 0.006), ellipsoid zone attenuation (P = 0.02), and increased lesion height and width (P < 0.001). Predictors of progression include diabetes mellitus (P = 0.01), statin use (P = 0.03), presence of hyperreflective foci (P = 0.01), and increased lesion width and volume (P = 0.03 and P = 0.04, respectively). Predictors of atrophy include the baseline presence of VMT (P = 0.02), decreased choroidal thickness (P = 0.03), and greater maximal height, width, and volume of the lesion (P = 0.03, P = 0.02, and P = 0.009, respectively). Lower baseline VA (P = 0.03) and increased lesion volume (P = 0.04) were associated with CNV. CONCLUSIONS Clinical and OCT imaging features at baseline may prove useful in stratifying patient risk for progression, atrophy, CNV, and worse VA. Features such as statin use, diabetes, baseline VA, and laterality should be accounted for. OCT features, such as lesion size, VMT, ellipsoid zone attenuation, choroidal thickness, and hyperreflective foci, may impart greater risk of poor outcomes. Future prospective analysis accounting for the time to development of atrophy and CNV is needed. FINANCIAL DISCLOSURES Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Grace E Nipp
- Department of Ophthalmology, Duke University Medical Center, Durham North Carolina
| | - Kubra Sarici
- Department of Ophthalmology, Duke University Medical Center, Durham North Carolina
| | - Terry Lee
- Department of Ophthalmology, Duke University Medical Center, Durham North Carolina
| | - Majda Hadziahmetovic
- Department of Ophthalmology, Duke University Medical Center, Durham North Carolina.
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Seah I, Goh D, Banerjee A, Su X. Modeling inherited retinal diseases using human induced pluripotent stem cell derived photoreceptor cells and retinal pigment epithelial cells. Front Med (Lausanne) 2024; 11:1328474. [PMID: 39011458 PMCID: PMC11246861 DOI: 10.3389/fmed.2024.1328474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 06/18/2024] [Indexed: 07/17/2024] Open
Abstract
Since the discovery of induced pluripotent stem cell (iPSC) technology, there have been many attempts to create cellular models of inherited retinal diseases (IRDs) for investigation of pathogenic processes to facilitate target discovery and validation activities. Consistency remains key in determining the utility of these findings. Despite the importance of consistency, quality control metrics are still not widely used. In this review, a toolkit for harnessing iPSC technology to generate photoreceptor, retinal pigment epithelial cell, and organoid disease models is provided. Considerations while developing iPSC-derived IRD models such as iPSC origin, reprogramming methods, quality control metrics, control strategies, and differentiation protocols are discussed. Various iPSC IRD models are dissected and the scientific hurdles of iPSC-based disease modeling are discussed to provide an overview of current methods and future directions in this field.
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Affiliation(s)
- Ivan Seah
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
| | - Debbie Goh
- Department of Ophthalmology, National University Hospital (NUH), Singapore, Singapore
| | - Animesh Banerjee
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xinyi Su
- Translational Retinal Research Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Ophthalmology, National University Hospital (NUH), Singapore, Singapore
- Singapore Eye Research Institute (SERI), Singapore, Singapore
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3
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Ngo WK, Fisher YL, Silverman RH, Tsang SH, Spaide RF. Scleral Thickness in Autosomal Dominant Best Vitelliform Macular Dystrophy. Retin Cases Brief Rep 2023; Publish Ahead of Print:01271216-990000000-00168. [PMID: 37104812 PMCID: PMC11090254 DOI: 10.1097/icb.0000000000001433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
PURPOSE To investigate the posterior and equatorial scleral thickness in patients with autosomal dominant Best disease, a condition that has chronic subretinal fluid. METHODS Retrospective study involving patients with Best disease and age-matched controls. Participants were evaluated with contact B-scan ultrasonography and enhanced depth imaging optical coherence tomography to evaluate scleral thickness in the posterior pole and equator. Univariate analysis and generalized estimating equations were used. RESULTS Of 9 patients with genetically proven Best disease and 23 age-matched controls, there was no significant difference in the age or the gender proportion between groups. Subfoveal choroidal thickness and axial length were not significantly different between groups. Both posterior scleral (OD; 1.38mm vs. 0.89mm, P<.001 and OS; 1.39mm vs. 0.83mm, P<.001) and equatorial scleral (OD; 0.61mm vs. 0.42mm, P=.003, and OS; 0.55mm vs. 0.41mm, P=.017) thicknesses were much greater in cases as compared with controls. Multivariate analysis showed male sex and having Best disease were each significant predictors of posterior scleral thickness and Best disease was the sole significant predictor for equatorial scleral thickness. CONCLUSION BEST1 gene may have a developmental role leading to having a thicker sclera, influencing disease manifestation, and contributing to the accumulation of subretinal fluid in Best disease.
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Affiliation(s)
- Wei Kiong Ngo
- Vitreous Retina Macula Consultants of New York, New York, NY, United States
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Medical Center, New York, NY, United States
- Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, United States
| | - Yale L. Fisher
- Vitreous Retina Macula Consultants of New York, New York, NY, United States
| | - Ronald H. Silverman
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Stephen H. Tsang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Medical Center, New York, NY, United States
- Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, United States
- Department of Pathology & Cell Biology, Institute of Human Nutrition, & Columbia Stem Cell Initiative, Columbia University, New York, NY, United States
| | - Richard F. Spaide
- Vitreous Retina Macula Consultants of New York, New York, NY, United States
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Zhao B, Chen L, Zhang P, He K, Lei M, Zhang J. Autosomal recessive bestrophinopathy combined with neurofibromatosis type 1 in a patient. BMC Ophthalmol 2023; 23:151. [PMID: 37041514 PMCID: PMC10088182 DOI: 10.1186/s12886-023-02905-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/05/2023] [Indexed: 04/13/2023] Open
Abstract
BACKGROUND Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder that may affect multiple systems of the body. Autosomal recessive bestrophinopathy (ARB) is a rare retinal dystrophy caused by autosomal recessively mutations in bestrophin 1 (BEST1) gene. So far, we have not retrieved any case report of the same patient with both NF1 and BEST1 gene mutations. CASE PRESENTATION An 8-year-old female patient with café-au-lait spots, freckling on skin presented to our ophthalmology clinic for routine ophthalmological examination. Her best corrected visual acuity (BCVA) was 20/20 in both eyes. Slit-lamp examination of both eyes revealed few yellowish-brown dome-shaped Lisch nodules over the iris surface. Fundus examination was notable for bilateral confluent yellowish subretinal deposits at macula, few yellow flecks at temporal retina, and cup-to-disc ratio of 0.2. Optical coherence tomography (OCT) revealed subretinal fluid (SRF) involving the fovea, elongated photoreceptor outer segments and mild intraretinal fluid (IRF) at bilateral macula. Fundus autofluorescence demonstrated hyperautofluorescence in the area corresponding to the subretinal deposits. Whole-exome sequencing and Sanger sequencing were used to investigate genetic mutation in the patient and her parents. A BEST1 gene heterozygous missense c.604 C > T (p.Arg202Trp) was identified in the patient and her mother. Also, the patient carries an NF1 nonsense mutation c.6637 C > T (p.Gln2213*) with the mosaic generalized phenotype. There were no visual impairments or obvious neurological, musculoskeletal, behavioral or other symptoms in this patient, so she was managed conservatively and advised to follow up regularly for a long time. CONCLUSIONS ARB and NF1, which are caused by two different pathogenic gene mutations, have rarely coexisted in the same patient. The discovery of pathogenic gene mutations may play a crucial role in more accurate diagnostics and genetic consultations for individuals and their families.
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Affiliation(s)
- Bo Zhao
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China
| | - Lian Chen
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China
| | - Peng Zhang
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China.
| | - Ke He
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China
| | - Min Lei
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China
| | - Juan Zhang
- Department of Ophthalmology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University, No.10 eastern section of the third fengcheng Road, Xi'an, 710018, China
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Cideciyan AV, Jacobson SG, Sumaroka A, Swider M, Krishnan AK, Sheplock R, Garafalo AV, Guziewicz KE, Aguirre GD, Beltran WA, Matsui Y, Kondo M, Heon E. Photoreceptor function and structure in retinal degenerations caused by biallelic BEST1 mutations. Vision Res 2023; 203:108157. [PMID: 36450205 PMCID: PMC9825664 DOI: 10.1016/j.visres.2022.108157] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/17/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022]
Abstract
The only approved retinal gene therapy is for biallelic RPE65 mutations which cause a recessive retinopathy with a primary molecular defect located at the retinal pigment epithelium (RPE). For a distinct recessive RPE disease caused by biallelic BEST1 mutations, a pre-clinical proof-of-concept for gene therapy has been demonstrated in canine eyes. The current study was undertaken to consider potential outcome measures for a BEST1 clinical trial in patients demonstrating a classic autosomal recessive bestrophinopathy (ARB) phenotype. Spatial distribution of retinal structure showed a wide expanse of abnormalities including large intraretinal cysts, shallow serous retinal detachments, abnormalities of inner and outer segments, and an unusual prominence of the external limiting membrane. Surrounding the central macula extending from 7 to 30 deg eccentricity, outer nuclear layer was thicker than expected from a cone only retina and implied survival of many rod photoreceptors. Co-localized however, were large losses of rod sensitivity despite preserved cone sensitivities. The dissociation of rod function from rod structure observed, supports a large treatment potential in the paramacular region for biallelic bestrophinopathies.
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Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arun K Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandra V Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Karina E Guziewicz
- Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William A Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yoshitsugu Matsui
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON M5G 2L3, Canada
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6
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Yang S, Li Z, Cheng W, Ma M, Qi R, Rui X, Ren Y, Sheng X, Rong W. BEST1 novel mutation causes Bestrophinopathies in six families with distinct phenotypic diversity. Mol Genet Genomic Med 2022; 11:e2095. [PMID: 36378562 PMCID: PMC9834154 DOI: 10.1002/mgg3.2095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To report novel BEST1 variants in six Chinese families with bestrophinopathies of two different inheritance modes and analyze the intrafamilial phenotypic diversity. METHOD A total of 25 participants including 13 patients and 12 healthy family members from 6 Chinese families with bestrophinopathies were available for genetic and clinical analysis. All of the patients were subjected to comprehensive ophthalmic evaluations and exome sequencing was performed on the probands to detect the causative variants. The pathogenicity of gene variants was predicted using silico analysis and evaluated according to ACMG guidelines. All (likely) pathogenic variants were determined by Sanger sequencing and co-segregation analyses were performed on available family members. The relevant original literature previously reported was retrieved to explore the relationship between BEST1-related gene variants and clinical features. RESULTS In the 6 families, 3 families (10 patients) were assigned as autosomal dominant bestrophinopathies (VMD) and 3 families (3 patients) were assigned as Autosomal recessive Bestrophinopathies (ARB). A total of 9 variants on the BEST1 gene were identified, containing 7 missense variants, 1 nonsense variant, and 1 frameshift variant, respectively, of which 3 variants c.88A > G (p.Lys30Glu), c.764G > A (p.Arg255Gln) and c.233dupT (p.Ser79Phefs*153) were novel variants. Three families with ARB were detected with heterozygous variants on the BEST1 gene.2 families (8 patients) with BVMD showed markedly irregular dominant inheritance, and the severity of macular lesions varies greatly among individuals of the same family. Among them, the probands showed typical vitelliform lesions in the macula, while the other six patients had no visible signs of the disease by fundus photography (ophthalmoscopy) and minor lesions could be detected on OCT in two patients, the continuity of the ellipsoidal band was interrupted with the chimeric band. The phenotypes of the patients in the three ARB families ranged from typical/atypical vitelliform lesions to extensive extramacular deposits (peripheral spots). CONCLUSION This study provided evidence that the phenotype of BVMD manifested irregular dominant inheritance, with patients carrying a pathogenic heterozygous variant of BEST1 to develop obvious intrafamilial phenotypic diversity, and the patients who harbor two pathogenic alleles showed recessive inheritance bestrophinopathies with distinct phenotypic diversity. Our study also emphasized the importance of comprehensive genetic analysis in patients with bestrophinopathies, and in such challenging families with distinct intrafamilial phenotypic diversity, it shall provide novel insights into phenotypic assessments of bestrophinopathies, and contribute to better diagnosis, prognosis, and treatment for these patients.
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Affiliation(s)
- Shangying Yang
- Clinical Medical CollegeNingxia Medical UniversityYinchuanChina
| | - Zhen Li
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous RegionThird Clinical Medical College of Ningxia Medical UniversityYinchuanChina
| | - Wanyu Cheng
- Clinical Medical CollegeNingxia Medical UniversityYinchuanChina
| | - Meijiao Ma
- Gansu Aier Ophthalmiology and Optometry HospitalLanzhou CityChina
| | - Rui Qi
- Aier Eye Hospital GroupHubin Aier Eye HospitalBinzhou CityChina
| | - Xue Rui
- Gansu Aier Ophthalmiology and Optometry HospitalLanzhou CityChina
| | - Yinghua Ren
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous RegionThird Clinical Medical College of Ningxia Medical UniversityYinchuanChina
| | - Xunlun Sheng
- Gansu Aier Ophthalmiology and Optometry HospitalLanzhou CityChina
| | - Weining Rong
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous RegionThird Clinical Medical College of Ningxia Medical UniversityYinchuanChina
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Impaired Bestrophin Channel Activity in an iPSC-RPE Model of Best Vitelliform Macular Dystrophy (BVMD) from an Early Onset Patient Carrying the P77S Dominant Mutation. Int J Mol Sci 2022; 23:ijms23137432. [PMID: 35806438 PMCID: PMC9266689 DOI: 10.3390/ijms23137432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/01/2022] [Indexed: 01/25/2023] Open
Abstract
Best Vitelliform Macular dystrophy (BVMD) is the most prevalent of the distinctive retinal dystrophies caused by mutations in the BEST1 gene. This gene, which encodes for a homopentameric calcium-activated ion channel, is crucial for the homeostasis and function of the retinal pigment epithelia (RPE), the cell type responsible for recycling the visual pigments generated by photoreceptor cells. In BVMD patients, mutations in this gene induce functional problems in the RPE cell layer with an accumulation of lipofucsin that evolves into cell death and loss of sight. In this work, we employ iPSC-RPE cells derived from a patient with the p.Pro77Ser dominant mutation to determine the correlation between this variant and the ocular phenotype. To this purpose, gene and protein expression and localization are evaluated in iPSC-RPE cells along with functional assays like phagocytosis and anion channel activity. Our cell model shows no differences in gene expression, protein expression/localization, or phagocytosis capacity, but presents an increased chloride entrance, indicating that the p.Pro77Ser variant might be a gain-of-function mutation. We hypothesize that this variant disturbs the neck region of the BEST1 channel, affecting channel function but maintaining cell homeostasis in the short term. This data shed new light on the different phenotypes of dominant mutations in BEST1, and emphasize the importance of understanding its molecular mechanisms. Furthermore, the data widen the knowledge of this pathology and open the door for a better diagnosis and prognosis of the disease.
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8
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Korkka I, Skottman H, Nymark S. OUP accepted manuscript. Stem Cells Transl Med 2022; 11:753-766. [PMID: 35639962 PMCID: PMC9299513 DOI: 10.1093/stcltm/szac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 04/09/2022] [Indexed: 11/15/2022] Open
Abstract
Human pluripotent stem cell (hPSC)-derived retinal pigment epithelium (RPE) is extensively used in RPE research, disease modeling, and transplantation therapies. For successful outcomes, a thorough evaluation of their physiological authenticity is a necessity. Essential determinants of this are the different ion channels of the RPE, yet studies evaluating this machinery in hPSC-RPE are scarce. We examined the functionality and localization of potassium (K+) channels in the human embryonic stem cell (hESC)-derived RPE. We observed a heterogeneous pattern of voltage-gated K+ (KV) and inwardly rectifying K+ (Kir) channels. Delayed rectifier currents were recorded from most of the cells, and immunostainings showed the presence of KV1.3 channel. Sustained M-currents were also present in the hESC-RPE, and based on immunostaining, these currents were carried by KCNQ1-KCNQ5 channel types. Some cells expressed transient A-type currents characteristic of native human fetal RPE (hfRPE) and cultured primary RPE and carried by KV1.4 and KV4.2 channels. Of the highly important Kir channels, we found that Kir7.1 is present both at the apical and basolateral membranes of the hESC- and fresh native mouse RPE. Kir currents, however, were recorded only from 14% of the hESC-RPE cells with relatively low amplitudes. Compared to previous studies, our data suggest that in the hESC-RPE, the characteristics of the delayed rectifier and M-currents resemble native adult RPE, while A-type and Kir currents resemble native hfRPE or cultured primary RPE. Overall, the channelome of the RPE is a sensitive indicator of maturity and functionality affecting its therapeutic utility.
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Affiliation(s)
- Iina Korkka
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Heli Skottman
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Soile Nymark
- Corresponding author: Soile Nymark, PhD, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland. Tel: +358 40 849 0009; E-mail:
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9
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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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10
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Shughoury A, Ciulla TA, Bakall B, Pennesi ME, Kiss S, Cunningham ET. Genes and Gene Therapy in Inherited Retinal Disease. Int Ophthalmol Clin 2021; 61:3-45. [PMID: 34584043 DOI: 10.1097/iio.0000000000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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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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12
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Liu F, Peng S, Adelman RA, Rizzolo LJ. Knockdown of Claudin-19 in the Retinal Pigment Epithelium Is Accompanied by Slowed Phagocytosis and Increased Expression of SQSTM1. Invest Ophthalmol Vis Sci 2021; 62:14. [PMID: 33591357 PMCID: PMC7900869 DOI: 10.1167/iovs.62.2.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 01/22/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose Besides regulating paracellular diffusion, claudin-19 modulates the expression of proteins essential for the retinal pigment epithelium (RPE). This study asks how RPE responds when the expression of claudin-19 is reduced. Methods In stem cell-derived RPE, claudin-19 and sequestosome-1/p62 (SQSTM1) were knocked down with siRNAs. Expression was monitored by quantitative RT-PCR and western blotting. Morphology and function were monitored by immunocytochemistry and transepithelial electrical resistance (TER). Phagocytosis of photoreceptor outer segments (POSs) was followed by fluorescence-activated cell sorting and western blotting. Pharmacology was used to assess the effects of AMP-activated protein kinase (AMPK) and SQSTM1 on phagocytosis. Enzymatic activity was measured using commercial assay kits. Results Knockdown of claudin-19 reduced the TER without affecting the integrity of the apical junctional complex, as assessed by the distribution of zonula occludens-1 and filamentous actin. AMPK was activated without apparent effect on autophagy. Activation of AMPK alone had little effect on phagocytosis. Without affecting ingestion, knockdown reduced the rate of POS degradation and increased the steady-state levels of LC3B and SQSTM1. Proteasome inhibitors also retarded degradation, as did knockdown of SQSTM1. The expression of metallothioneins and the activity of superoxide dismutase increased. Conclusions Knockdown of claudin-19 slowed the degradation of internalized POSs. The study questions the role of activated AMPK in phagocytosis and suggests a role for SQSTM1. Further, knockdown was associated with a partial oxidative stress response. The study opens new avenues of experimentation to explore these essential RPE functions.
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Affiliation(s)
- Fanfei Liu
- Aier School of Ophthalmology, Central South University, Changsha, China
- Department of Surgery, Yale University, New Haven, Connecticut, United States
- Deparment of Ophthalmology and Visual Science, Yale University, New Haven, Connecticut, United States
| | - Shaomin Peng
- Aier School of Ophthalmology, Central South University, Changsha, China
| | - Ron A. Adelman
- Deparment of Ophthalmology and Visual Science, Yale University, New Haven, Connecticut, United States
| | - Lawrence J. Rizzolo
- Department of Surgery, Yale University, New Haven, Connecticut, United States
- Deparment of Ophthalmology and Visual Science, Yale University, New Haven, Connecticut, United States
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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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Sinha D, Steyer B, Shahi PK, Mueller KP, Valiauga R, Edwards KL, Bacig C, Steltzer SS, Srinivasan S, Abdeen A, Cory E, Periyasamy V, Siahpirani AF, Stone EM, Tucker BA, Roy S, Pattnaik BR, Saha K, Gamm DM. Human iPSC Modeling Reveals Mutation-Specific Responses to Gene Therapy in a Genotypically Diverse Dominant Maculopathy. Am J Hum Genet 2020; 107:278-292. [PMID: 32707085 DOI: 10.1016/j.ajhg.2020.06.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/12/2020] [Indexed: 12/26/2022] Open
Abstract
Dominantly inherited disorders are not typically considered to be therapeutic candidates for gene augmentation. Here, we utilized induced pluripotent stem cell-derived retinal pigment epithelium (iPSC-RPE) to test the potential of gene augmentation to treat Best disease, a dominant macular dystrophy caused by over 200 missense mutations in BEST1. Gene augmentation in iPSC-RPE fully restored BEST1 calcium-activated chloride channel activity and improved rhodopsin degradation in an iPSC-RPE model of recessive bestrophinopathy as well as in two models of dominant Best disease caused by different mutations in regions encoding ion-binding domains. A third dominant Best disease iPSC-RPE model did not respond to gene augmentation, but showed normalization of BEST1 channel activity following CRISPR-Cas9 editing of the mutant allele. We then subjected all three dominant Best disease iPSC-RPE models to gene editing, which produced premature stop codons specifically within the mutant BEST1 alleles. Single-cell profiling demonstrated no adverse perturbation of retinal pigment epithelium (RPE) transcriptional programs in any model, although off-target analysis detected a silent genomic alteration in one model. These results suggest that gene augmentation is a viable first-line approach for some individuals with dominant Best disease and that non-responders are candidates for alternate approaches such as gene editing. However, testing gene editing strategies for on-target efficiency and off-target events using personalized iPSC-RPE model systems is warranted. In summary, personalized iPSC-RPE models can be used to select among a growing list of gene therapy options to maximize safety and efficacy while minimizing time and cost. Similar scenarios likely exist for other genotypically diverse channelopathies, expanding the therapeutic landscape for affected individuals.
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Affiliation(s)
- Divya Sinha
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Benjamin Steyer
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Pawan K Shahi
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Katherine P Mueller
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Rasa Valiauga
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Cole Bacig
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Stephanie S Steltzer
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Sandhya Srinivasan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Amr Abdeen
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Evan Cory
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Viswesh Periyasamy
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | | | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Budd A Tucker
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Sushmita Roy
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biostatistics, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Bikash R Pattnaik
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53792, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Krishanu Saha
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - David M Gamm
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA.
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Xuan Y, Zhang Y, Zong Y, Wang M, Li L, Ye X, Liu W, Chen J, Sun X, Zhang Y, Chen Y. The Clinical Features and Genetic Spectrum of a Large Cohort of Chinese Patients With Vitelliform Macular Dystrophies. Am J Ophthalmol 2020; 216:69-79. [PMID: 32278767 DOI: 10.1016/j.ajo.2020.03.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 11/18/2022]
Abstract
PURPOSE To provide the clinical and genetic characteristics of a large cohort of Chinese patients with vitelliform macular dystrophies. DESIGN Cross-sectional study. METHODS One hundred and thirty-four unrelated Chinese patients diagnosed with Best vitelliform macular dystrophy (BVMD), autosomal recessive bestrophinopathy (ARB), or adult vitelliform macular dystrophy (AVMD) were enrolled. Detailed ophthalmic examinations and genetic testing on vitelliform macular dystrophy-related genes were performed. Genotype and phenotype association were analyzed among different diagnostic groups. RESULTS In total, 87 BVMD, 30 AVMD, and 17 ARB patients were enrolled in this study. Genetic analysis identified 37 BEST1 mutations in 53 patients with BVMD and ARB. Of these, 5 variants (c.254A>C, c.291C>G, c.722C>G, c.848_850del, c.1740-2A>C) were novel. The variant c.898G>A was a hotspot mutation, which was identified in 13 patients with BVMD and 1 patient with ARB. There were significant differences of ocular biometric parameters among patients with homozygous or compound heterozygous mutations, heterozygous mutations, and those without mutations of BEST1. Homozygous or compound heterozygous patients had shortest axial length (AL), shallowest anterior chamber depth (ACD), and highest intraocular pressure (IOP); patients without mutations had longest AL, deepest ACD, and lowest IOP; and heterozygous patients were in between. Moreover, 7 patients harboring heterozygous mutations in BEST1 and 3 patients without BEST1 mutations showed similar clinical appearance to ARB in our cohort. CONCLUSIONS This is the largest sample size study of Chinese vitelliform macular dystrophy patients. Our results indicated that assessment of angle-closure risk is a necessary consideration for all types of BEST1-related vitelliform macular dystrophies. The study expanded both the clinical and genetic findings of 3 common types of vitelliform macular dystrophies in a Chinese population.
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Affiliation(s)
- Yi Xuan
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Youjia Zhang
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Yuan Zong
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia, Fudan University, Chinese Academy of Medical Sciences, Shanghai, China
| | - Min Wang
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Lei Li
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Xiaofeng Ye
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Wei Liu
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Junyi Chen
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia, Fudan University, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia, Fudan University, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yongjin Zhang
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Yuhong Chen
- Department of Ophthalmology & Visual Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China; NHC Key Laboratory of Myopia, Fudan University, Chinese Academy of Medical Sciences, Shanghai, China.
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16
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Doxorubicin generates senescent microglia that exhibit altered proteomes, higher levels of cytokine secretion, and a decreased ability to internalize amyloid β. Exp Cell Res 2020; 395:112203. [PMID: 32738344 DOI: 10.1016/j.yexcr.2020.112203] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/16/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022]
Abstract
Cellular senescence is defined by irreversible cell-cycle arrest and is an evolutionarily conserved hallmark of aging. In this study, we generate senescent microglial cells via exposure to the chemotherapy drug doxorubicin. Compared to control cells, doxorubicin-treated microglia exhibited an altered morphology characterized by an enlarged cell size, a flattened appearance, and the development of prominent filaments. Senescent cells harbored elevated levels of senescence associated-β-galactosidase, p16Ink4a, and γ-H2AX. Senescent microglia were also less efficient at internalizing amyloid β and pHrodo bioparticles. A detailed proteomic analysis using SWATH-MS identified 201 proteins that were significantly downregulated and 127 that were significantly upregulated in doxorubicin-treated microglia. Proteins involved in processes such as protein synthesis, RNA damage and repair, and protein degradation were largely downregulated while those compromising the integrity of the cell were predominantly upregulated. Various proteins involved in proteasomal processing were among the most significantly downregulated in senescent cells. Relevant to the deleterious senescence-associated secretory phenotype, senescent cells secreted higher levels of the inflammatory cytokines IL-6, IL-8, TNF-α, and GRO-α. Our data suggest that symptoms of brain aging and age-related neurodegenerative disease may be partially caused by defective phagocytosis, impaired proteasomal processing, and elevated cytokine secretion of senescent microglia.
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17
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Gao T, Tian C, Xu H, Tang X, Huang L, Zhao M. Disease-causing mutations associated with bestrophinopathies promote apoptosis in retinal pigment epithelium cells. Graefes Arch Clin Exp Ophthalmol 2020; 258:2251-2261. [PMID: 32507900 DOI: 10.1007/s00417-020-04636-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 02/17/2020] [Accepted: 02/24/2020] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB) are two kinds of bestrophinopathies which are caused by BEST1 mutations and characterized by accumulation of lipofuscin-like materials on the retinal pigment epithelium cell-photoreceptor interface. In the past two decades, research about the pathogenesis of bestrophinopathies was mainly focused on the anion channel and intracellular Ca2+ signaling, but seldom concentrated on the function of retinal pigment epithelium (RPE) cells. In this study, we explored the possible effect of the three BEST1 mutations p.V143F, p.S142G, and p.A146T on the apoptosis in human fetal RPE cells. METHODS Wild-type plasmid and mutant plasmids BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T were transfected to human fetal RPE cells. The molecules caspase-3, phospho-Bcl-2, BAX, PARP, and AIF associated with apoptosis were determined by quantitative PCR and Western blot. Apoptotic rate and active Caspase-3 staining were analyzed by flow cytometry. RESULTS Caspase-3 and PARP expression were significantly increased in BEST1-pcDNA3.1 p.S142G and p.A146T group. Flow cytometry showed that the apoptosis rates were significantly increased in the BEST1-pcDNA3.1 p.V143F, p.S142G, and p.A146T group compared with the wild-type group. CONCLUSIONS For the first time, we found that the three mutations promoted RPE cell apoptosis. Furthermore, the results indicated that BEST1 mutations p.S142G and p.A146T may contribute apoptosis of RPE cells by targeting Caspase 3. Our observations suggested that the apoptosis of RPE cells may be one of the mechanisms in bestrophinopathies, which may provide a new potential therapeutic target for the treatment of this disease.
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Affiliation(s)
- Tingting Gao
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Department of Ophthalmology & Clinical Centre of Optometry, Eye diseases and optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Peking University People's Hospital, Xizhimen South Street 11, Xi Cheng District, Beijing, 100044, China
| | - Chengqiang Tian
- Department of Ophthalmology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Hui Xu
- Department of Ophthalmology & Clinical Centre of Optometry, Eye diseases and optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Peking University People's Hospital, Xizhimen South Street 11, Xi Cheng District, Beijing, 100044, China
| | - Xin Tang
- Department of Ophthalmology & Clinical Centre of Optometry, Eye diseases and optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Peking University People's Hospital, Xizhimen South Street 11, Xi Cheng District, Beijing, 100044, China
| | - Lvzhen Huang
- Department of Ophthalmology & Clinical Centre of Optometry, Eye diseases and optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Peking University People's Hospital, Xizhimen South Street 11, Xi Cheng District, Beijing, 100044, China.
| | - Mingwei Zhao
- Department of Ophthalmology & Clinical Centre of Optometry, Eye diseases and optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Peking University People's Hospital, Xizhimen South Street 11, Xi Cheng District, Beijing, 100044, China.
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18
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Phosphoinositides in Retinal Function and Disease. Cells 2020; 9:cells9040866. [PMID: 32252387 PMCID: PMC7226789 DOI: 10.3390/cells9040866] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play many important roles in all eukaryotic cells. These include modulation of physical properties of membranes, activation or inhibition of membrane-associated proteins, recruitment of peripheral membrane proteins that act as effectors, and control of membrane trafficking. They also serve as precursors for important second messengers, inositol (1,4,5) trisphosphate and diacylglycerol. Animal models and human diseases involving defects in phosphoinositide regulatory pathways have revealed their importance for function in the mammalian retina and retinal pigmented epithelium. New technologies for localizing, measuring and genetically manipulating them are revealing new information about their importance for the function and health of the vertebrate retina.
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19
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Mutation-Dependent Pathomechanisms Determine the Phenotype in the Bestrophinopathies. Int J Mol Sci 2020; 21:ijms21051597. [PMID: 32111077 PMCID: PMC7084480 DOI: 10.3390/ijms21051597] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022] Open
Abstract
Best vitelliform macular dystrophy (BD), autosomal dominant vitreoretinochoroidopathy (ADVIRC), and the autosomal recessive bestrophinopathy (ARB), together known as the bestrophinopathies, are caused by mutations in the bestrophin-1 (BEST1) gene affecting anion transport through the plasma membrane of the retinal pigment epithelium (RPE). To date, while no treatment exists a better understanding of BEST1-related pathogenesis may help to define therapeutic targets. Here, we systematically characterize functional consequences of mutant BEST1 in thirteen RPE patient cell lines differentiated from human induced pluripotent stem cells (hiPSCs). Both BD and ARB hiPSC-RPEs display a strong reduction of BEST1-mediated anion transport function compared to control, while ADVIRC mutations trigger an increased anion permeability suggesting a stabilized open state condition of channel gating. Furthermore, BD and ARB hiPSC-RPEs differ by the degree of mutant protein turnover and by the site of subcellular protein quality control with adverse effects on lysosomal pH only in the BD-related cell lines. The latter finding is consistent with an altered processing of catalytic enzymes in the lysosomes. The present study provides a deeper insight into distinct molecular mechanisms of the three bestrophinopathies facilitating functional categorization of the more than 300 known BEST1 mutations that result into the distinct retinal phenotypes.
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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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21
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Dalvin LA, Hartnett ME, Bretz CA, Hann CR, Cui RZ, Marmorstein AD, Sheikh-Hamad D, Fautsch MP, Roddy GW. Stanniocalcin-1 is a Modifier of Oxygen-Induced Retinopathy Severity. Curr Eye Res 2020; 45:46-51. [PMID: 31314602 PMCID: PMC6898771 DOI: 10.1080/02713683.2019.1645184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 01/21/2023]
Abstract
Purpose/Aim: Abnormal activation of signaling pathways related to angiogenesis, inflammation, and oxidative stress has been implicated in the pathophysiology of retinopathy of prematurity (ROP), a leading cause of blindness in pre-term infants. Therapies for ROP include laser and anti-vascular endothelial growth factor agents. However, these therapies have side effects, and even with adequate treatment, visual acuity can be impaired. Novel therapeutic options are needed. Stanniocalcin-1 (STC-1) is a neuroprotective protein with anti-inflammatory and anti-oxidative stress properties. Rodent models of oxygen-induced retinopathy (OIR) were selected to determine whether STC-1 plays a role in the development of OIR.Materials and methods: STC-1 gene and protein expression was first evaluated in the Sprague Dawley rat OIR model that is most similar to human ROP. OIR was then induced in wild-type and Stc-1-/- mice. Retinas were isolated and evaluated for avascular and neovascular area on retinal flat mounts. Quantification of gene expression by quantitative real-time PCR was performed. VEGF was assayed by ELISA in media obtained from induced pluripotent stem-cell-derived retinal pigment epithelial (iPS-RPE) cells following treatment with recombinant STC-1.Results: STC-1 was significantly upregulated in a rat model of OIR compared to room air controls at the gene (P < .05) and protein (P < .001) level. Stc-1-/- OIR mice showed significantly worse ROP compared to wild-type mice as assessed by avascular (20.2 ± 2.4% vs 15.2 ± 2.5%; P = .02) and neovascular area (14.3 ± 2.7% vs 8.8 ± 3.7%; P < .05). Transcript levels of vascular endothelial growth factor-A were significantly higher in Stc-1-/- OIR mice compared to wild-type controls (P = .03). STC-1 reduced VEGF production in iPS-RPE cells (P = .01).Conclusions: STC-1 plays a role in the OIR stress response and development of pathologic vascular features in rodent OIR models by regulating VEGF levels.
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Affiliation(s)
| | | | | | - Cheryl R. Hann
- Department of Ophthalmology, Mayo Clinic, Rochester, MN,
55905
| | - Ricky Z Cui
- West Suburban Medical Center, Oak Park, IL 60302
| | | | - David Sheikh-Hamad
- Department of Nephrology, Baylor College of Medicine,
Houston, TX, 77030
| | | | - Gavin W. Roddy
- Department of Ophthalmology, Mayo Clinic, Rochester, MN,
55905
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22
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Abstract
Bestrophinopathies are a group of clinically distinct inherited retinal dystrophies that lead to the gradual loss of vision in and around the macular area. There are no treatments for patients suffering from bestrophinopathies, and no measures can be taken to prevent visual deterioration in those who have inherited disease-causing mutations. Bestrophinopathies are caused by mutations in the Bestrophin1 gene (BEST1), a protein found exclusively in the retinal pigment epithelial (RPE) cells of the eye. Mutations in BEST1 affect the function of the RPE leading to the death of overlying retinal cells and subsequent vision loss. The pathogenic mechanisms arising from BEST1 mutations are still not fully understood, and it is not clear how mutations in BEST1 lead to diseases with distinct clinical features. This chapter discusses BEST1, the use of model systems to investigate the effects of mutations and the potential to investigate individual bestrophinopathies using induced pluripotent stem cells.
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Linderman RE, Cava JA, Salmon AE, Chui TY, Marmorstein AD, Lujan BJ, Rosen RB, Carroll J. Visual Acuity and Foveal Structure in Eyes with Fragmented Foveal Avascular Zones. Ophthalmol Retina 2019; 4:535-544. [PMID: 31956075 DOI: 10.1016/j.oret.2019.11.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/08/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Abstract
PURPOSE To assess the frequency and impact of abnormal foveal avascular zone (FAZ) topography (i.e., a fragmented FAZ) on visual acuity and foveal anatomic features. DESIGN Prospective, cross-sectional study from March 2018 through July 2019. PARTICIPANTS Two-hundred fifty participants were screened from a normative OCT angiography database. Of those, 12 participants were found to have at least 1 eye with a fragmented FAZ. Eight returned for follow-up imaging, along with an additional 3 participants with ocular disease (amblyopia, autosomal recessive bestrophinopathy, premature birth) having a similar FAZ phenotype. METHODS Follow-up OCT imaging and monocular best-corrected visual acuity (BCVA) were performed for these 11 participants. Twenty-four participants with a clearly defined FAZ were recruited for comparison. A normative database was created measuring parafoveal intercapillary area (PICA) to determine if an FAZ was fragmented. MAIN OUTCOME MEASURES Monocular BCVA, foveal pit depth, foveal pit area, PICA, outer nuclear layer thickness, foveal inner retinal area, and peak cone density. RESULTS The frequency of a fragmented FAZ was 4.8% of individuals (12 of 250) or 3.6% of eyes (18 of 500 eyes). A significant difference was found between the control eyes and eyes with fragmented FAZs for foveal pit depth, pit area, and total PICA (P < 0.001, P = 0.002, and P < 0.001, respectively). The presence of a fragmented FAZ did not affect visual acuity. CONCLUSIONS The presence of a fragmented FAZ seems not to be a rare phenotype in individuals with normal vision. The presence of altered FAZ topography in patients with retinal or systemic disease could negatively impact the accuracy and sensitivity of biomarkers dependent on FAZ identification.
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Affiliation(s)
- Rachel E Linderman
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jenna A Cava
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alexander E Salmon
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Toco Y Chui
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York; Icahn School of Medicine at Mount Sinai, New York, New York
| | | | - Brandon J Lujan
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Richard B Rosen
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, New York; Icahn School of Medicine at Mount Sinai, New York, New York
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin.
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24
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Witsberger E, Marmorstein A, Pulido J. Diffuse Outer Layer Opacification: A Novel Finding in Patients With Autosomal Recessive Bestrophinopathy. Asia Pac J Ophthalmol (Phila) 2019; 8:469-475. [PMID: 31789649 PMCID: PMC6903339 DOI: 10.1097/apo.0000000000000261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Autosomal recessive bestrophinopathy (ARB) is a rare inherited retinal dystrophy resulted from mutations in bestrophin-1 (BEST1) which affect functioning of the retinal pigment epithelium (RPE). Descriptions of disease findings in patients with ARB to date have focused only on macular changes. In this case series, we report previously undescribed mid-peripheral retinal changes occurring in 4 patients with ARB. DESIGN Case series. METHODS A single-center, retrospective review of medical records from Mayo Clinic patients with ARB was performed. Imaging reviewed include fundus photography, fundus autofluorescence, spectral domain optical coherence tomography (OCT), and fluorescein angiography. Demographic information and disease progression were noted. RESULTS 4 affected patients from 3 families were identified. All 4 patients were female, and mean age was 12.5 years (range 5-19 years). Diffuse mid-peripheral whitening was consistently noted on fundus photography. Concomitant OCT imaging demonstrated areas of hyperreflectivity in the photoreceptor outer segment layer in areas corresponding to whitening seen on fundus photography. In 1 patient who was followed for 12 years, this finding persisted. Subretinal fluid was also consistently present. Other pathologic imaging findings observed in each patient were in agreement with previous reports of ARB. CONCLUSIONS This is the first descriptive report of pathologic findings occurred beyond the posterior pole in patients with ARB. These mid-peripheral retinal changes potentially imply that the entirety of the RPE is affected by mutations in BEST1, as also suggested by previous electro-oculogram (EOG) findings. Such implications will be important when developing treatment trials, as past trials have focused only on the posterior pole of the RPE.
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25
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Lin TC, Lin YY, Hsu CC, Yang YP, Yang CH, Hwang DK, Wang CY, Liu YY, Lo WL, Chiou SH, Peng CH, Chen SJ, Chang YL. Nanomedicine-based Curcumin Approach Improved ROS Damage in Best Dystrophy-specific Induced Pluripotent Stem Cells. Cell Transplant 2019; 28:1345-1357. [PMID: 31313605 PMCID: PMC6802151 DOI: 10.1177/0963689719860130] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Best dystrophy (BD), also termed best vitelliform macular dystrophy (BVMD), is a
juvenile-onset form of macular degeneration and can cause central visual loss.
Unfortunately, there is no clear definite therapy for BD or improving the visual function
on this progressive disease. The human induced pluripotent stem cell (iPSC) system has
been recently applied as an effective tool for genetic consultation and chemical drug
screening. In this study, we developed patient-specific induced pluripotent stem cells
(BD-iPSCs) from BD patient-derived dental pulp stromal cells and then differentiated
BD-iPSCs into retinal pigment epithelial cells (BD-RPEs). BD-RPEs were used as an
expandable platform for in vitro candidate drug screening. Compared with unaffected
sibling-derived iPSC-derived RPE cells (Ctrl-RPEs), BD-RPEs exhibited typical RPE-specific
markers with a lower expression of the tight junction protein ZO-1 and Bestrophin-1
(BEST1), as well as reduced phagocytic capabilities. Notably, among all candidate drugs,
curcumin was the most effective for upregulating both the BEST1 and ZO-1 genes in BD-RPEs.
Using the iPSC-based drug-screening platform, we further found that curcumin can
significantly improve the mRNA expression levels of Best gene in BD-iPSC-derived RPEs.
Importantly, we demonstrated that curcumin-loaded PLGA nanoparticles (Cur-NPs) were
efficiently internalized by BD-RPEs. The Cur-NPs-based controlled release formulation
further increased the expression of ZO-1 and Bestrophin-1, and promoted the function of
phagocytosis and voltage-dependent calcium channels in BD-iPSC-derived RPEs. We further
demonstrated that Cur-NPs enhanced the expression of antioxidant enzymes with a decrease
in intracellular ROS production and hydrogen peroxide-induced oxidative stress.
Collectively, these data supported that Cur-NPs provide a potential cytoprotective effect
by regulating the anti-oxidative abilities of degenerated RPEs. In addition, the
application of patient-specific iPSCs provides an effective platform for drug screening
and personalized medicine in incurable diseases.
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Affiliation(s)
- Tai-Chi Lin
- Institute of Clinical Medicine, National Yang-Ming University, Taipei.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei
| | - Yi-Ying Lin
- Institute of Pharmacology, National Yang-Ming University, Taipei
| | - Chih-Chen Hsu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei
| | - Yi-Ping Yang
- Institute of Pharmacology, National Yang-Ming University, Taipei.,School of Medicine, National Yang-Ming University, Taipei.,Department of Medical Research, Taipei Veterans General Hospital, Taipei
| | - Chang-Hao Yang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei
| | - De-Kuang Hwang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei.,School of Medicine, National Yang-Ming University, Taipei
| | - Chien-Ying Wang
- School of Medicine, National Yang-Ming University, Taipei.,Department of Critical Care Medicine, Taipei Veterans General Hospital, Taipei
| | - Yung-Yang Liu
- School of Medicine, National Yang-Ming University, Taipei.,Department of Chest, Taipei Veterans General Hospital, Taipei
| | - Wen-Liang Lo
- Department of Stomatology, Taipei Veterans General Hospital & Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei
| | - Shih-Hwa Chiou
- Institute of Clinical Medicine, National Yang-Ming University, Taipei.,Institute of Pharmacology, National Yang-Ming University, Taipei.,Department of Medical Research, Taipei Veterans General Hospital, Taipei
| | - Chi-Hsien Peng
- Department of Ophthalmology, Shin Kong Wu Ho-Su Memorial Hospital & Fu-Jen Catholic University, Taipei
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei.,School of Medicine, National Yang-Ming University, Taipei
| | - Yuh-Lih Chang
- Institute of Pharmacology, National Yang-Ming University, Taipei.,School of Medicine, National Yang-Ming University, Taipei.,Department of Pharmacology, Taipei Veterans General Hospital, Taipei.,School of Pharmaceutical Sciences, National Yang-Ming University, Taipei
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26
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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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27
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Dalvi S, Galloway CA, Winschel L, Hashim A, Soto C, Tang C, MacDonald LA, Singh R. Environmental stress impairs photoreceptor outer segment (POS) phagocytosis and degradation and induces autofluorescent material accumulation in hiPSC-RPE cells. Cell Death Discov 2019; 5:96. [PMID: 31123602 PMCID: PMC6522536 DOI: 10.1038/s41420-019-0171-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 11/09/2022] Open
Abstract
Retinal pigment epithelium (RPE) cell dysfunction is central to the pathogenesis of age-related macular degeneration (AMD), a leading cause of adult blindness. Aging, the single biggest risk factor for AMD development, favors increase in RPE autofluorescent material due to accumulation of POS-digestion by-products through lysosomal dysfunction and impaired POS degradation. Apart from aging, environmental agents affect lysosomal function in multiple model systems and are implicated in AMD. Iron (Fe) overload and cigarette smoke exposure are the two environmental factors that are known to affect the lysosomal pathway and impact RPE cell health. However, the impact of Fe and cigarette smoke, on POS processing and its consequence for autofluorescent material accumulation in human RPE cells are yet to be established. Human induced pluripotent stem cell (hiPSC)-derived RPE, which phagocytoses and degrades POS in culture and can be derived from control individuals (no history/susceptibility for retinal disease), provides a model system to investigate the singular effect of excess Fe and/or cigarette smoke on POS processing by RPE cells. Using at least three distinct control hiPSC lines, we show that, compared to untreated hiPSC-RPE cells, POS uptake is reduced in both Fe (ferric ammonium citrate or FAC) and FAC + CSE (cigarette smoke extract)-treated hiPSC-RPE cells. Furthermore, exposure of hiPSC-RPE cultures to FAC + CSE leads to reduced levels of active cathepsin-D (CTSD), a lysosomal enzyme involved in POS processing, and causes delayed degradation of POS. Notably, delayed degradation of POS over time (2 weeks) in hiPSC-RPE cells exposed to Fe and CSE was sufficient to increase autofluorescent material build-up in these cells. Given that inefficient POS processing-mediated autofluorescent material accumulation in RPE cells has already been linked to AMD development, our results implicate a causative role of environmental agents, like Fe and cigarette smoke, in AMD.
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Affiliation(s)
- Sonal Dalvi
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Chad A Galloway
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA.,5Present Address: Department of Pathology and Lab Medicine, University of Rochester, Rochester, NY USA
| | - Lauren Winschel
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Ali Hashim
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Celia Soto
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Cynthia Tang
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Leslie A MacDonald
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA
| | - Ruchira Singh
- 1Department of Ophthalmology (Flaum Eye Institute), University of Rochester, Rochester, NY USA.,2Department of Biomedical Genetics, University of Rochester, Rochester, NY USA.,3UR Stem Cell and Regenerative Medicine Institute, Rochester, NY USA.,4Center for Visual Science, University of Rochester, Rochester, NY USA
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28
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Gandhi JK, Knudsen T, Hill M, Roy B, Bachman L, Pfannkoch‐Andrews C, Schmidt KN, Metko MM, Ackerman MJ, Resch Z, Pulido JS, Marmorstein AD. Human Fibrinogen for Maintenance and Differentiation of Induced Pluripotent Stem Cells in Two Dimensions and Three Dimensions. Stem Cells Transl Med 2019; 8:512-521. [PMID: 30768863 PMCID: PMC6525556 DOI: 10.1002/sctm.18-0189] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/20/2018] [Indexed: 02/06/2023] Open
Abstract
Human fibrin hydrogels are a popular choice for use as a biomaterial within tissue engineered constructs because they are biocompatible, nonxenogenic, autologous use compatible, and biodegradable. We have recently demonstrated the ability to culture induced pluripotent stem cell (iPSC)‐derived retinal pigment epithelium on fibrin hydrogels. However, iPSCs themselves have relatively few substrate options (e.g., laminin) for expansion in adherent cell culture for use in cell therapy. To address this, we investigated the potential of culturing iPSCs on fibrin hydrogels for three‐dimensional applications and further examined the use of fibrinogen, the soluble precursor protein, as a coating substrate for traditional adherent cell culture. iPSCs successfully adhered to and proliferated on fibrin hydrogels. The two‐dimensional culture with fibrinogen allows for immediate adaption of culture models to a nonxenogeneic model. Similarly, multiple commercially available iPSC lines adhered to and proliferated on fibrinogen coated surfaces. iPSCs cultured on fibrinogen expressed similar levels of the pluripotent stem cell markers SSea4 (98.7% ± 1.8%), Oct3/4 (97.3% ± 3.8%), TRA1‐60 (92.2% ± 5.3%), and NANOG (96.0% ± 3.9%) compared with iPSCs on Geltrex. Using a trilineage differentiation assay, we found no difference in the ability of iPSCs grown on fibrinogen or Geltrex to differentiate to endoderm, mesoderm, or ectoderm. Finally, we demonstrated the ability to differentiate iPSCs to endothelial cells using only fibrinogen coated plates. On the basis of these data, we conclude that human fibrinogen provides a readily available and inexpensive alternative to laminin‐based products for the growth, expansion, and differentiation of iPSCs for use in research and clinical cell therapy applications. stem cells translational medicine2019;8:512–521
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Affiliation(s)
| | - Travis Knudsen
- Department of OphthalmologyMayo ClinicRochesterMinnesotaUSA
| | - Matthew Hill
- Department of OphthalmologyMayo ClinicRochesterMinnesotaUSA
| | - Bhaskar Roy
- Center for Regenerative MedicineMayo ClinicRochesterMinnesotaUSA
| | - Lori Bachman
- Department of OphthalmologyMayo ClinicRochesterMinnesotaUSA
| | | | | | | | - Michael J. Ackerman
- Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental TherapeuticsMayo ClinicRochesterMinnesotaUSA
| | - Zachary Resch
- Center for Regenerative MedicineMayo ClinicRochesterMinnesotaUSA
| | - Jose S. Pulido
- Department of OphthalmologyMayo ClinicRochesterMinnesotaUSA
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29
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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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30
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Ratnayaka JA, Keeling E, Chatelet DS. Study of Intracellular Cargo Trafficking and Co-localization in the Phagosome and Autophagy-Lysosomal Pathways of Retinal Pigment Epithelium (RPE) Cells. Methods Mol Biol 2019; 2150:167-182. [PMID: 30969403 DOI: 10.1007/7651_2019_223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The transport and targeting of internalized molecules to distinct intracellular organelles/compartments can prove challenging to visualize clearly, which can contribute to some of the difficulties associated with these studies. By combining several approaches, we show how the trafficking and processing of photoreceptor outer segments in the phagosome and autophagy-lysosomal pathways of the retinal pigment epithelium (RPE) can easily be quantified and visualized as 3D-reconstructed images. This protocol takes advantage of new developments in microscopy and image-analysis software which has the potential to help better understand dynamic intracellular processes that underlie RPE dysfunction associated with irreversible blinding diseases such as age-related macular degeneration. The method described herein can also be used to study the trafficking and co-localization of different intracellular cargos in other cell types and tissues.
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Affiliation(s)
- J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - David S Chatelet
- Biomedical Imaging Unit, University of Southampton, Southampton, UK
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31
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Foltz LP, Howden SE, Thomson JA, Clegg DO. Functional Assessment of Patient-Derived Retinal Pigment Epithelial Cells Edited by CRISPR/Cas9. Int J Mol Sci 2018; 19:E4127. [PMID: 30572641 PMCID: PMC6321630 DOI: 10.3390/ijms19124127] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa is the most common form of inherited blindness and can be caused by a multitude of different genetic mutations that lead to similar phenotypes. Specifically, mutations in ubiquitously expressed splicing factor proteins are known to cause an autosomal dominant form of the disease, but the retina-specific pathology of these mutations is not well understood. Fibroblasts from a patient with splicing factor retinitis pigmentosa caused by a missense mutation in the PRPF8 splicing factor were used to produce three diseased and three CRISPR/Cas9-corrected induced pluripotent stem cell (iPSC) clones. We differentiated each of these clones into retinal pigment epithelial (RPE) cells via directed differentiation and analyzed the RPE cells in terms of gene and protein expression, apicobasal polarity, and phagocytic ability. We demonstrate that RPE cells can be produced from patient-derived and corrected cells and they exhibit morphology and functionality similar but not identical to wild-type RPE cells in vitro. Functionally, the RPE cells were able to establish apicobasal polarity and phagocytose photoreceptor outer segments at the same capacity as wild-type cells. These data suggest that patient-derived iPSCs, both diseased and corrected, are able to differentiate into RPE cells with a near normal phenotype and without differences in phagocytosis, a result that differs from previous mouse models. These RPE cells can now be studied to establish a disease-in-a-dish system relevant to retinitis pigmentosa.
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Affiliation(s)
- Leah P Foltz
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA.
| | - Sara E Howden
- Murdoch Children's Research Institute, University of Melbourne, Parkville 3052, Australia.
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53715, USA.
| | - James A Thomson
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53715, USA.
| | - Dennis O Clegg
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA.
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32
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Rohani L, Johnson AA, Naghsh P, Rancourt DE, Ulrich H, Holland H. Concise Review: Molecular Cytogenetics and Quality Control: Clinical Guardians for Pluripotent Stem Cells. Stem Cells Transl Med 2018; 7:867-875. [PMID: 30218497 PMCID: PMC6265634 DOI: 10.1002/sctm.18-0087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/07/2018] [Indexed: 12/13/2022] Open
Abstract
Now that induced pluripotent stem cell (iPSC)‐based transplants have been performed in humans and organizations have begun producing clinical‐grade iPSCs, it is imperative that strict quality control standards are agreed upon. This is essential as both ESCs and iPSCs have been shown to accumulate genomic aberrations during long‐term culturing. These aberrations can include copy number variations, trisomy, amplifications of chromosomal regions, deletions of chromosomal regions, loss of heterozygosity, and epigenetic abnormalities. Moreover, although the differences between iPSCs and ESCs appear largely negligible when a high enough n number is used for comparison, the reprogramming process can generate further aberrations in iPSCs, including copy number variations and deletions in tumor‐suppressor genes. If mutations or epigenetic signatures are present in parental cells, these can also be carried over into iPSCs. To maximize patient safety, we recommend a set of standards to be utilized when preparing iPSCs for clinical use. Reprogramming methods that do not involve genomic integration should be used. Cultured cells should be grown using feeder‐free and serum‐free systems to avoid animal contamination. Karyotyping, whole‐genome sequencing, gene expression analyses, and standard sterility tests should all become routine quality control tests. Analysis of mitochondrial DNA integrity, whole‐epigenome analyses, as well as single‐cell genome sequencing of large cell populations may also prove beneficial. Furthermore, clinical‐grade stem cells need to be produced under accepted regulatory good manufacturing process standards. The creation of haplobanks that provide major histocompatibility complex matching is also recommended to improve allogeneic stem cell engraftment. Stem Cells Translational Medicine2018;7:867–875
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Affiliation(s)
- Leili Rohani
- Saxonian Incubator for Clinical Translation (SIKT), University of Leipzig, Leipzig, Germany.,Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Adiv A Johnson
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
| | - Pooyan Naghsh
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Derrick E Rancourt
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Heidrun Holland
- Saxonian Incubator for Clinical Translation (SIKT), University of Leipzig, Leipzig, Germany
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Foltz LP, Clegg DO. Patient-derived induced pluripotent stem cells for modelling genetic retinal dystrophies. Prog Retin Eye Res 2018; 68:54-66. [PMID: 30217765 DOI: 10.1016/j.preteyeres.2018.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 12/22/2022]
Abstract
The human retina is a highly complex tissue that makes up an integral part of our central nervous system. It is astonishing that our retina works seamlessly to provide one of our most critical senses, and it is equally devastating when a disease destroys a portion of the retina and robs people of their vision. After decades of research, scientists are beginning to understand retinal cells in a way that can benefit the millions of individuals suffering from inherited blindness. This understanding has come about in part with the ability to culture human embryonic stem cells and the innovation of induced pluripotent stem cells, which can be cultured from patients and used to model their disease. In this review, we highlight the successes of specific disease modelling studies and resulting molecular discoveries. The greatest strides in cellular modelling have come from mutations in genes with established and well-understood cellular functions in the context of the retina. We believe that the future of cellular modelling depends on emphasising reproducible production of retinal cell types, demonstrating functional rescue using site-specific programmable nucleases, and shifting towards unbiased screening using next generation sequencing.
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Affiliation(s)
- Leah P Foltz
- Biochemistry and Molecular Biology, University of California, Santa Barbara, CA, USA; Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, CA, USA.
| | - Dennis O Clegg
- Biochemistry and Molecular Biology, University of California, Santa Barbara, CA, USA; Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, CA, USA
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