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Tsikandelova R, Galo E, Cerniauskas E, Hallam D, Georgiou M, Cerna-Chavez R, Atkinson R, Palmowski P, Burté F, Davies T, Steel DH, McKibbin M, Bond J, Haggarty J, Whitfield P, Korolchuk V, Armstrong L, Yang C, Dorgau B, Kurzawa-Akanbi M, Lako M. Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation. Stem Cell Reports 2024:S2213-6711(24)00155-3. [PMID: 38964324 DOI: 10.1016/j.stemcr.2024.06.002] [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: 04/04/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 07/06/2024] Open
Abstract
Biallelic mutations in DRAM2 lead to an autosomal recessive cone-rod dystrophy known as CORD21, which typically presents between the third and sixth decades of life. Although DRAM2 localizes to the lysosomes of photoreceptor and retinal pigment epithelium (RPE) cells, its specific role in retinal degeneration has not been fully elucidated. In this study, we generated and characterized retinal organoids (ROs) and RPE cells from induced pluripotent stem cells (iPSCs) derived from two CORD21 patients. Our investigation revealed that CORD21-ROs and RPE cells exhibit abnormalities in lipid metabolism, defects in autophagic flux, accumulation of aberrant lysosomal content, and reduced lysosomal enzyme activity. We identified potential interactions of DRAM2 with vesicular trafficking proteins, suggesting its involvement in this cellular process. These findings collectively suggest that DRAM2 plays a crucial role in maintaining the integrity of photoreceptors and RPE cells by regulating lysosomal function, autophagy, and potentially vesicular trafficking.
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Affiliation(s)
| | - Eldo Galo
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Dean Hallam
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Maria Georgiou
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | | | | | - Florence Burté
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Tracey Davies
- Electron Microscopy Research Services, Newcastle University, Newcastle, UK
| | - David H Steel
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Martin McKibbin
- Leeds Teaching Hospitals NHS Trust, Leeds UK and Leeds Institute for Medical Research, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Jacquelyn Bond
- Leeds Teaching Hospitals NHS Trust, Leeds UK and Leeds Institute for Medical Research, St. James's University Hospital, University of Leeds, Leeds, UK
| | - Jennifer Haggarty
- Shared Research Facilities, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Phil Whitfield
- Glasgow Polyomics and Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | | | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Chunbo Yang
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Birthe Dorgau
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle, UK.
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Jones MK, Orozco LD, Qin H, Truong T, Caplazi P, Elstrott J, Modrusan Z, Chaney SY, Jeanne M. Integration of human stem cell-derived in vitro systems and mouse preclinical models identifies complex pathophysiologic mechanisms in retinal dystrophy. Front Cell Dev Biol 2023; 11:1252547. [PMID: 37691820 PMCID: PMC10483287 DOI: 10.3389/fcell.2023.1252547] [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: 07/03/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023] Open
Abstract
Rare DRAM2 coding variants cause retinal dystrophy with early macular involvement via unknown mechanisms. We found that DRAM2 is ubiquitously expressed in the human eye and expression changes were observed in eyes with more common maculopathy such as Age-related Macular Degeneration (AMD). To gain insights into pathogenicity of DRAM2-related retinopathy, we used a combination of in vitro and in vivo models. We found that DRAM2 loss in human pluripotent stem cell (hPSC)-derived retinal organoids caused the presence of additional mesenchymal cells. Interestingly, Dram2 loss in mice also caused increased proliferation of cells from the choroid in vitro and exacerbated choroidal neovascular lesions in vivo. Furthermore, we observed that DRAM2 loss in human retinal pigment epithelial (RPE) cells resulted in increased susceptibility to stress-induced cell death in vitro and that Dram2 loss in mice caused age-related photoreceptor degeneration. This highlights the complexity of DRAM2 function, as its loss in choroidal cells provided a proliferative advantage, whereas its loss in post-mitotic cells, such as photoreceptor and RPE cells, increased degeneration susceptibility. Different models such as human pluripotent stem cell-derived systems and mice can be leveraged to study and model human retinal dystrophies; however, cell type and species-specific expression must be taken into account when selecting relevant systems.
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Affiliation(s)
- Melissa K. Jones
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, United States
- Product Development Clinical Science Ophthalmology, Genentech Inc., South San Francisco, CA, United States
| | - Luz D. Orozco
- Department of Bioinformatics, Genentech Inc., South San Francisco, CA, United States
| | - Han Qin
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, United States
| | - Tom Truong
- Department of Translational Immunology, Genentech Inc., South San Francisco, CA, United States
| | - Patrick Caplazi
- Department of Research Pathology, Genentech Inc., South San Francisco, CA, United States
| | - Justin Elstrott
- Department of Translational Imaging, Genentech Inc., South San Francisco, CA, United States
| | - Zora Modrusan
- Department of Microchemistry, Proteomics, Lipidomics and Next-Generation Sequencing, Genentech Inc., South San Francisco, CA, United States
| | - Shawnta Y. Chaney
- Department of Translational Immunology, Genentech Inc., South San Francisco, CA, United States
| | - Marion Jeanne
- Department of Neuroscience, Genentech Inc., South San Francisco, CA, United States
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The Clinical Spectrum and Disease Course of DRAM2 Retinopathy. Int J Mol Sci 2022; 23:ijms23137398. [PMID: 35806404 PMCID: PMC9266529 DOI: 10.3390/ijms23137398] [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: 05/31/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 11/26/2022] Open
Abstract
Pathogenic variants in DNA-damage regulated autophagy modulator 2 gene (DRAM2) cause a rare autosomal recessive retinal dystrophy and its disease course is not well understood. We present two Slovenian patients harboring a novel DRAM2 variant and a detailed review of all 23 other patients described to date. Whole exome and whole genome sequencing were performed in the two patients, and both underwent ophthalmological examination with a 2-year follow-up. PubMed was searched for papers with clinical descriptions of DRAM2 retinopathy. Patient 1 was homozygous for a novel variant, p.Met1?, and presented with the acute onset of photopsia and retina-wide retinopathy at the age of 35 years. The patient was first thought to have an autoimmune retinopathy and was treated with mycophenolate mofetil, which provided some symptomatic relief. Patient 2 was compound heterozygous for p.Met1? and p.Leu246Pro and presented with late-onset maculopathy at the age of 59 years. On review, patients with DRAM2 retinopathy usually present in the third decade with central visual loss, outer retinal layer loss on optical coherence tomography and a hyperautofluorescent ring on fundus autofluorescence. Either cone–rod or rod–cone dystrophy phenotype is observed on electroretinography, reflecting the importance of DRAM2 in both photoreceptor types. Non-null variants can result in milder disease.
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Mizobuchi K, Hayashi T, Yoshitake K, Fujinami K, Tachibana T, Tsunoda K, Iwata T, Nakano T. Novel homozygous CLN3 missense variant in isolated retinal dystrophy: A case report and electron microscopic findings. Mol Genet Genomic Med 2020; 8:e1308. [PMID: 32441891 PMCID: PMC7434607 DOI: 10.1002/mgg3.1308] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/16/2022] Open
Abstract
Background Biallelic CLN3 gene variants have been found in either juvenile‐onset neuronal ceroid lipofuscinosis (JNCL) or isolated retinal dystrophy. It has been reported that most JNCL patients carry a common 1.02‐kb deletion variant homozygously. Clinical characteristics of patients with biallelic CLN3 missense variants are not well elucidated. Methods We described a 26‐year‐old Japanese male patient with isolated retinal dystrophy. Whole‐exome sequencing (WES) and transmission electron microscopy (TEM) were performed. Results Whole‐exome sequencing identified a novel homozygous CLN3 missense variant [c.482C>T; p.(Ser161Leu)]. Ophthalmoscopy revealed retinal degeneration and macular atrophy, and later attenuated retinal vessels. Severely reduced responses were observed in both rod and cone electroretinograms. In TEM of the patient's lymphocytes, fingerprint profiles, which are specific findings in CLN3‐associated JNCL, were observed in 16/624 (2.56%) lymphocytes of the patient, who has never exhibited neurological signs during the 13‐year follow‐up period. Conclusion Our results indicated that this novel CLN3 missense variant is associated with teenage‐onset isolated retinal dystrophy. This is the first report of any patient with CLN3‐associated disorder in the Japanese population. Although fingerprint profiles have never been reported in CLN3‐associated isolated retinal dystrophy, these profiles were observed, albeit infrequently, suggesting that frequency of the fingerprint profiles might depend on variant types.
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Affiliation(s)
- Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan
| | - Kazutoshi Yoshitake
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Kaoru Fujinami
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Toshiaki Tachibana
- Core Research Facilities for Basic Science, Research Center for Medical Science, The Jikei University School of Medicine, Tokyo, Japan
| | - Kazushige Tsunoda
- Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
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