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Kurzawa-Akanbi M, Tzoumas N, Corral-Serrano JC, Guarascio R, Steel DH, Cheetham ME, Armstrong L, Lako M. Pluripotent stem cell-derived models of retinal disease: Elucidating pathogenesis, evaluating novel treatments, and estimating toxicity. Prog Retin Eye Res 2024; 100:101248. [PMID: 38369182 DOI: 10.1016/j.preteyeres.2024.101248] [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: 12/07/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Blindness poses a growing global challenge, with approximately 26% of cases attributed to degenerative retinal diseases. While gene therapy, optogenetic tools, photosensitive switches, and retinal prostheses offer hope for vision restoration, these high-cost therapies will benefit few patients. Understanding retinal diseases is therefore key to advance effective treatments, requiring in vitro models replicating pathology and allowing quantitative assessments for drug discovery. Pluripotent stem cells (PSCs) provide a unique solution given their limitless supply and ability to differentiate into light-responsive retinal tissues encompassing all cell types. This review focuses on the history and current state of photoreceptor and retinal pigment epithelium (RPE) cell generation from PSCs. We explore the applications of this technology in disease modelling, experimental therapy testing, biomarker identification, and toxicity studies. We consider challenges in scalability, standardisation, and reproducibility, and stress the importance of incorporating vasculature and immune cells into retinal organoids. We advocate for high-throughput automation in data acquisition and analyses and underscore the value of advanced micro-physiological systems that fully capture the interactions between the neural retina, RPE, and choriocapillaris.
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Lima Cunha D, Sarkar H, Eintracht J, Harding P, Zhou JH, Moosajee M. Restoration of functional PAX6 in aniridia patient iPSC-derived ocular tissue models using repurposed nonsense suppression drugs. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:240-253. [PMID: 37483273 PMCID: PMC10362734 DOI: 10.1016/j.omtn.2023.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/22/2023] [Indexed: 07/25/2023]
Abstract
Congenital aniridia is a rare, pan-ocular disease causing severe sight loss, with only symptomatic intervention offered to patients. Approximately 40% of aniridia patients present with heterozygous nonsense variants in PAX6, resulting in haploinsufficiency. Translational readthrough-inducing drugs (TRIDs) have the ability to weaken the recognition of in-frame premature termination codons (PTCs), permitting full-length protein to be translated. We established induced pluripotent stem cell (iPSC)-derived 3D optic cups and 2D limbal epithelial stem cell (LESC) models from two aniridia patients with prevalent PAX6 nonsense mutations. Both in vitro models show reduced PAX6 protein levels, mimicking the disease. The repurposed TRIDs amlexanox and 2,6-diaminopurine (DAP) and the positive control compounds ataluren and G418 were tested for their efficiency. Amlexanox was identified as the most promising TRID, increasing full-length PAX6 levels in both models and rescuing the disease phenotype through normalization of VSX2 and cell proliferation in the optic cups and reduction of ABCG2 protein and SOX10 expression in LESCs. This study highlights the significance of patient iPSC-derived cells as a new model system for aniridia and proposes amlexanox as a new putative treatment for nonsense-mediated aniridia.
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Affiliation(s)
- Dulce Lima Cunha
- UCL Institute of Ophthalmology, London, UK
- Radboud Institute of Molecular Life Sciences, Radboud University, Nijmegen, the Netherlands
| | - Hajrah Sarkar
- UCL Institute of Ophthalmology, London, UK
- The Francis Crick Institute, London, UK
| | | | | | - Jo Huiqing Zhou
- Radboud Institute of Molecular Life Sciences, Radboud University, Nijmegen, the Netherlands
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, UK
- The Francis Crick Institute, London, UK
- Moorfields Eye Hospital, London, UK
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Li S, Li J, Shi W, Nie Z, Zhang S, Ma F, Hu J, Chen J, Li P, Xie X. Pharmaceuticals Promoting Premature Termination Codon Readthrough: Progress in Development. Biomolecules 2023; 13:988. [PMID: 37371567 DOI: 10.3390/biom13060988] [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] [Received: 04/25/2023] [Revised: 05/27/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Around 11% of all known gene lesions causing human genetic diseases are nonsense mutations that introduce a premature stop codon (PTC) into the protein-coding gene sequence. Drug-induced PTC readthrough is a promising therapeutic strategy for treating hereditary diseases caused by nonsense mutations. To date, it has been found that more than 50 small-molecular compounds can promote PTC readthrough, known as translational readthrough-inducing drugs (TRIDs), and can be divided into two major categories: aminoglycosides and non-aminoglycosides. This review summarizes the pharmacodynamics and clinical application potential of the main TRIDs discovered so far, especially some newly discovered TRIDs in the past decade. The discovery of these TRIDs brings hope for treating nonsense mutations in various genetic diseases. Further research is still needed to deeply understand the mechanism of eukaryotic cell termination and drug-induced PTC readthrough so that patients can achieve the greatest benefit from the various TRID treatments.
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Affiliation(s)
- Shan Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Juan Li
- Central Laboratory, The First Hospital of Lanzhou University, Lanzhou 730000, China
- Gansu Key Laboratory of Genetic Study of Hematopathy, The First Hospital of Lanzhou University, Lanzhou 730000, China
| | - Wenjing Shi
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ziyan Nie
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Shasha Zhang
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Fengdie Ma
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jun Hu
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jianjun Chen
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Peiqiang Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaodong Xie
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
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Recoding of Nonsense Mutation as a Pharmacological Strategy. Biomedicines 2023; 11:biomedicines11030659. [PMID: 36979640 PMCID: PMC10044939 DOI: 10.3390/biomedicines11030659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Approximately 11% of genetic human diseases are caused by nonsense mutations that introduce a premature termination codon (PTC) into the coding sequence. The PTC results in the production of a potentially harmful shortened polypeptide and activation of a nonsense-mediated decay (NMD) pathway. The NMD pathway reduces the burden of unproductive protein synthesis by lowering the level of PTC mRNA. There is an endogenous rescue mechanism that produces a full-length protein from a PTC mRNA. Nonsense suppression therapies aim to increase readthrough, suppress NMD, or are a combination of both strategies. Therefore, treatment with translational readthrough-inducing drugs (TRIDs) and NMD inhibitors may increase the effectiveness of PTC suppression. Here we discuss the mechanism of PTC readthrough and the development of novel approaches to PTC suppression. We also discuss the toxicity and bioavailability of therapeutics used to stimulate PTC readthrough.
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Corrao F, Zizzo MG, Tutone M, Melfi R, Fiduccia I, Carollo PS, Leonardo AD, Caldara G, Perriera R, Pace A, Belmonte B, Sammataro S, Pibiri I, Lentini L. Nonsense codons suppression. An acute toxicity study of three optimized TRIDs in murine model, safety and tolerability evaluation. Biomed Pharmacother 2022; 156:113886. [DOI: 10.1016/j.biopha.2022.113886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/02/2022] Open
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Leung A, Sacristan-Reviriego A, Perdigão PRL, Sai H, Georgiou M, Kalitzeos A, Carr AJF, Coffey PJ, Michaelides M, Bainbridge J, Cheetham ME, van der Spuy J. Investigation of PTC124-mediated translational readthrough in a retinal organoid model of AIPL1-associated Leber congenital amaurosis. Stem Cell Reports 2022; 17:2187-2202. [PMID: 36084639 PMCID: PMC9561542 DOI: 10.1016/j.stemcr.2022.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 10/26/2022] Open
Abstract
Leber congenital amaurosis type 4 (LCA4), caused by AIPL1 mutations, is characterized by severe sight impairment in infancy and rapidly progressing degeneration of photoreceptor cells. We generated retinal organoids using induced pluripotent stem cells (iPSCs) from renal epithelial cells obtained from four children with AIPL1 nonsense mutations. iPSC-derived photoreceptors exhibited the molecular hallmarks of LCA4, including undetectable AIPL1 and rod cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE6) compared with control or CRISPR-corrected organoids. Increased levels of cGMP were detected. The translational readthrough-inducing drug (TRID) PTC124 was investigated as a potential therapeutic agent. LCA4 retinal organoids exhibited low levels of rescue of full-length AIPL1. However, this was insufficient to fully restore PDE6 in photoreceptors and reduce cGMP. LCA4 retinal organoids are a valuable platform for in vitro investigation of novel therapeutic agents.
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Affiliation(s)
- Amy Leung
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | | | | | - Hali Sai
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | | | | | - Michel Michaelides
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - James Bainbridge
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
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Sarkar H, Moosajee M. Choroideremia: molecular mechanisms and therapies. Trends Mol Med 2022; 28:378-387. [PMID: 35341685 DOI: 10.1016/j.molmed.2022.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/28/2022] [Accepted: 02/28/2022] [Indexed: 10/18/2022]
Abstract
Choroideremia (CHM) is a monogenic X-linked chorioretinal dystrophy affecting the photoreceptors, retinal pigment epithelium (RPE), and choroid; it is caused by mutations involving the CHM gene. CHM is characterized by night blindness in early childhood, progressing to peripheral visual field loss and eventually to complete blindness from middle age. CHM encodes the ubiquitously expressed Rab escort protein 1 (REP1), which is responsible for prenylation of Rab proteins and is essential for intracellular trafficking of vesicles. In this review we explore the role of REP1 in the retina and its newly discovered systemic manifestations, and discuss the therapeutic strategies for tackling this disease, including the outcomes from recent clinical trials.
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Affiliation(s)
- Hajrah Sarkar
- Development, Ageing, and Disease, University College London (UCL) Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Mariya Moosajee
- Development, Ageing, and Disease, University College London (UCL) Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK; Department of Genetics, Moorfields Eye Hospital National Health Service (NHS) Foundation Trust, London, EC1V 2PD, UK; Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
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Kalatzis V, Roux AF, Meunier I. Molecular Therapy for Choroideremia: Pre-clinical and Clinical Progress to Date. Mol Diagn Ther 2021; 25:661-675. [PMID: 34661884 DOI: 10.1007/s40291-021-00558-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 12/01/2022]
Abstract
Choroideremia is an inherited retinal disease characterised by a degeneration of the light-sensing photoreceptors, supporting retinal pigment epithelium and underlying choroid. Patients present with the same symptoms as those with classic rod-cone dystrophy: (1) night blindness early in life; (2) progressive peripheral visual field loss, and (3) central vision decline with a slow progression to legal blindness. Choroideremia is monogenic and caused by mutations in CHM. Eight clinical trials (three phase 1/2, four phase 2, and one phase 3) have started (four of which are already finished) to evaluate the therapeutic efficacy of gene supplementation mediated by subretinal delivery of an adeno-associated virus serotype 2 (AAV2/2) vector expressing CHM. Furthermore, one phase 1 clinical trial has been initiated to evaluate the efficiency of a novel AAV variant to deliver CHM to the outer retina following intravitreal delivery. Lastly, a non-viral-mediated CHM replacement strategy is currently under development, which could lead to a future clinical trial. Here, we summarise the rationale behind these various studies, as well as any results published to date. The diversity of these trials currently places choroideremia at the forefront of the retinal gene therapy field. As a consequence, the trial outcomes, regardless of the results, have the potential to change the landscape of gene supplementation for inherited retinal diseases.
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Affiliation(s)
- Vasiliki Kalatzis
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.
| | - Anne-Françoise Roux
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.,Molecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, University of Montpellier, CHU Montpellier, Montpellier, France
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Eintracht J, Forsythe E, May-Simera H, Moosajee M. Translational readthrough of ciliopathy genes BBS2 and ALMS1 restores protein, ciliogenesis and function in patient fibroblasts. EBioMedicine 2021; 70:103515. [PMID: 34365092 PMCID: PMC8353411 DOI: 10.1016/j.ebiom.2021.103515] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/13/2021] [Accepted: 07/19/2021] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Ciliary dysfunction underlies a range of genetic disorders collectively termed ciliopathies, for which there are no treatments available. Bardet-Biedl syndrome (BBS) is characterised by multisystemic involvement, including rod-cone dystrophy and renal abnormalities. Together with Alström syndrome (AS), they are known as the 'obesity ciliopathies' due to their common phenotype. Nonsense mutations are responsible for approximately 11% and 40% of BBS and AS cases, respectively. Translational readthrough inducing drugs (TRIDs) can restore full-length protein bypassing in-frame premature termination codons, and are a potential therapeutic approach for nonsense-mediated ciliopathies. METHODS Patient fibroblasts harbouring nonsense mutations from two different ciliopathies (Bardet-Biedl Syndrome and Alström Syndrome) were treated with PTC124 (ataluren) or amlexanox. Following treatment, gene expression, protein levels and ciliogenesis were evaluated. The expression of intraflagellar transport protein IFT88 and G-protein coupled receptor SSTR3 was investigated as a readout of ciliary function. FINDINGS mRNA expression was significantly increased in amlexanox-treated patient fibroblasts, and full-length BBS2 or ALMS1 protein expression was restored in PTC124- and amlexanox-treated fibroblasts. Treatment with TRIDs significantly improved ciliogenesis defects in BBS2Y24*/R275* fibroblasts. Treatment recovered IFT88 expression and corrected SSTR3 mislocalisation in BBS2Y24*/R275* and ALMS1S1645*/S1645* fibroblasts, suggesting rescue of ciliary function. INTERPRETATION The recovery of full-length BBS2 and ALMS1 expression and correction of anatomical and functional ciliary defects in BBS2Y24*/R275* and ALMS1S1645*/S1645* fibroblasts suggest TRIDs are a potential therapeutic option for the treatment of nonsense-mediated ciliopathies. FUNDING Wellcome Trust 205174/Z/16/Z, National Centre for the Replacement, Refinement & Reduction of Animals in Research. Deutsche Forschungsgemeinschaft SPP2127 (DFG Grant MA 6139/3-1).
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Affiliation(s)
| | - Elizabeth Forsythe
- Clinical Genetics Unit, Great Ormond Street Hospital; Genetics and Genomic Medicine Programme, Great Ormond Street Institute of Child Health
| | - Helen May-Simera
- Institute of Molecular Physiology, Johannes Gutenburg University, Mainz
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, United Kingdom; The Francis Crick Institute, London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom.
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Schilff M, Sargsyan Y, Hofhuis J, Thoms S. Stop Codon Context-Specific Induction of Translational Readthrough. Biomolecules 2021; 11:biom11071006. [PMID: 34356630 PMCID: PMC8301745 DOI: 10.3390/biom11071006] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/11/2022] Open
Abstract
Premature termination codon (PTC) mutations account for approximately 10% of pathogenic variants in monogenic diseases. Stimulation of translational readthrough, also known as stop codon suppression, using translational readthrough-inducing drugs (TRIDs) may serve as a possible therapeutic strategy for the treatment of genetic PTC diseases. One important parameter governing readthrough is the stop codon context (SCC)-the stop codon itself and the nucleotides in the vicinity of the stop codon on the mRNA. However, the quantitative influence of the SCC on treatment outcome and on appropriate drug concentrations are largely unknown. Here, we analyze the readthrough-stimulatory effect of various readthrough-inducing drugs on the SCCs of five common premature termination codon mutations of PEX5 in a sensitive dual reporter system. Mutations in PEX5, encoding the peroxisomal targeting signal 1 receptor, can cause peroxisomal biogenesis disorders of the Zellweger spectrum. We show that the stop context has a strong influence on the levels of readthrough stimulation and impacts the choice of the most effective drug and its concentration. These results highlight potential advantages and the personalized medicine nature of an SCC-based strategy in the therapy of rare diseases.
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Affiliation(s)
- Mirco Schilff
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
- Correspondence: ; Tel.: +49-521-106-86502
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Cunha DL, Richardson R, Tracey-White D, Abbouda A, Mitsios A, Horneffer-van der Sluis V, Takis P, Owen N, Skinner J, Welch AA, Moosajee M. REP1 deficiency causes systemic dysfunction of lipid metabolism and oxidative stress in choroideremia. JCI Insight 2021; 6:146934. [PMID: 33755601 PMCID: PMC8262314 DOI: 10.1172/jci.insight.146934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/17/2021] [Indexed: 12/17/2022] Open
Abstract
Choroideremia (CHM) is an X-linked recessive chorioretinal dystrophy caused by mutations in CHM, encoding for Rab escort protein 1 (REP1). Loss of functional REP1 leads to the accumulation of unprenylated Rab proteins and defective intracellular protein trafficking, the putative cause for photoreceptor, retinal pigment epithelium (RPE), and choroidal degeneration. CHM is ubiquitously expressed, but adequate prenylation is considered to be achieved, outside the retina, through the isoform REP2. Recently, the possibility of systemic features in CHM has been debated; therefore, in this study, whole metabolomic analysis of plasma samples from 25 CHM patients versus age- and sex-matched controls was performed. Results showed plasma alterations in oxidative stress-related metabolites, coupled with alterations in tryptophan metabolism, leading to significantly raised serotonin levels. Lipid metabolism was disrupted with decreased branched fatty acids and acylcarnitines, suggestive of dysfunctional lipid oxidation, as well as imbalances of several sphingolipids and glycerophospholipids. Targeted lipidomics of the chmru848 zebrafish provided further evidence for dysfunction, with the use of fenofibrate over simvastatin circumventing the prenylation pathway to improve the lipid profile and increase survival. This study provides strong evidence for systemic manifestations of CHM and proposes potentially novel pathomechanisms and targets for therapeutic consideration.
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Affiliation(s)
- Dulce Lima Cunha
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Rose Richardson
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Dhani Tracey-White
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Alessandro Abbouda
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Andreas Mitsios
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | | | - Panteleimon Takis
- MRC-NIHR National Phenome Centre, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Nicholas Owen
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
| | - Jane Skinner
- Department of Public Health & Primary Care, Norwich Medical School, Norfolk, United Kingdom
| | - Ailsa A. Welch
- Department of Public Health & Primary Care, Norwich Medical School, Norfolk, United Kingdom
| | - Mariya Moosajee
- Department of Development, Ageing and Disease, UCL Institute of Ophthalmology, London, United Kingdom
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
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Martins-Dias P, Romão L. Nonsense suppression therapies in human genetic diseases. Cell Mol Life Sci 2021; 78:4677-4701. [PMID: 33751142 PMCID: PMC11073055 DOI: 10.1007/s00018-021-03809-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/06/2021] [Accepted: 03/05/2021] [Indexed: 02/06/2023]
Abstract
About 11% of all human disease-associated gene lesions are nonsense mutations, resulting in the introduction of an in-frame premature translation-termination codon (PTC) into the protein-coding gene sequence. When translated, PTC-containing mRNAs originate truncated and often dysfunctional proteins that might be non-functional or have gain-of-function or dominant-negative effects. Therapeutic strategies aimed at suppressing PTCs to restore deficient protein function-the so-called nonsense suppression (or PTC readthrough) therapies-have the potential to provide a therapeutic benefit for many patients and in a broad range of genetic disorders, including cancer. These therapeutic approaches comprise the use of translational readthrough-inducing compounds that make the translational machinery recode an in-frame PTC into a sense codon. However, most of the mRNAs carrying a PTC can be rapidly degraded by the surveillance mechanism of nonsense-mediated decay (NMD), thus decreasing the levels of PTC-containing mRNAs in the cell and their availability for PTC readthrough. Accordingly, the use of NMD inhibitors, or readthrough-compound potentiators, may enhance the efficiency of PTC suppression. Here, we review the mechanisms of PTC readthrough and their regulation, as well as the recent advances in the development of novel approaches for PTC suppression, and their role in personalized medicine.
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Affiliation(s)
- Patrícia Martins-Dias
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, 1749-016, Lisbon, Portugal
| | - Luísa Romão
- Department of Human Genetics, Instituto Nacional de Saúde Doutor Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, 1749-016, Lisbon, Portugal.
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Kong R, Ma J, Hwang S, Moon YC, Welch EM, Weetall M, Colacino JM, Almstead N, Babiak J, Goodwin E. In vitro metabolism, reaction phenotyping, enzyme kinetics, CYP inhibition and induction potential of ataluren. Pharmacol Res Perspect 2021; 8:e00576. [PMID: 32196986 PMCID: PMC7083565 DOI: 10.1002/prp2.576] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 01/06/2023] Open
Abstract
Ataluren promotes ribosomal readthrough of premature termination codons in mRNA which result from nonsense mutations. In vitro studies were performed to characterize the metabolism and enzyme kinetics of ataluren and its interaction potential with CYP enzymes. Incubation of [14C]‐ataluren with human liver microsomes indicated that the major metabolic pathway for ataluren is via direct glucuronidation and that the drug is not metabolized via cytochrome P450 (CYP). Glucuronidation was also observed in the incubation in human intestinal and kidney microsomes, but not in human pulmonary microsomes. UGT1A9 was found to be the major uridine diphosphate glucuronosyltransferase (UGT) responsible for ataluren glucuronidation in the liver and kidney microsomes. Enzyme kinetic analysis of the formation of ataluren acyl glucuronide, performed in human liver, kidney, and intestinal microsomes and recombinant human UGT1A9, found that increasing bovine serum albumin (BSA) levels enhanced the glucuronidation Michaelis‐Menten constant (Km) and ataluren protein binding but had a minimal effect on maximum velocity (Vmax) of glucuronidation. Due to the decreased unbound Michaelis‐Menten constant (Km,u), the ataluren unbound intrinsic clearance (CLint,u) increased for all experimental systems and BSA concentrations. Human kidney microsomes were about 3.7‐fold more active than human liver microsomes, in terms of CLint,u/mg protein, indicating that the kidney is also a key organ for the metabolism and disposition of ataluren in humans. Ataluren showed no or little potential to inhibit or induce most of the CYP enzymes.
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Affiliation(s)
- Ronald Kong
- PTC Therapeutics, Inc., South Plainfield, NJ, USA
| | - Jiyuan Ma
- PTC Therapeutics, Inc., South Plainfield, NJ, USA
| | | | | | | | | | | | | | - John Babiak
- PTC Therapeutics, Inc., South Plainfield, NJ, USA
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14
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Han RC, Fry LE, Kantor A, McClements ME, Xue K, MacLaren RE. Is subretinal AAV gene replacement still the only viable treatment option for choroideremia? Expert Opin Orphan Drugs 2021; 9:13-24. [PMID: 34040899 PMCID: PMC7610829 DOI: 10.1080/21678707.2021.1882300] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/25/2021] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Choroideremia is an X-linked inherited retinal degeneration resulting from mutations in the CHM gene, encoding Rab escort protein-1 (REP1), a protein regulating intracellular vesicular transport. Loss-of-function mutations in CHM lead to progressive loss of retinal pigment epithelium (RPE) with photoreceptor and choriocapillaris degeneration, leading to progressive visual field constriction and loss of visual acuity. Three hundred and fifty-four unique mutations have been reported in CHM. While gene augmentation remains an ideal therapeutic option for choroideremia, other potential future clinical strategies may exist. AREAS COVERED The authors examine the pathophysiology and genetic basis of choroideremia. They summarize the status of ongoing gene therapy trials and discuss CHM mutations amenable to other therapeutic approaches including CRISPR/Cas-based DNA and RNA editing, nonsense suppression of premature termination codons, and antisense oligonucleotides for splice modification. The authors undertook a literature search in PubMed and NIH Clinical Trials in October 2020. EXPERT OPINION The authors conclude that AAV-mediated gene augmentation remains the most effective approach for choroideremia. Given the heterogeneity of CHM mutations and potential risks and benefits, genome-editing approaches currently do not offer significant advantages. Nonsense suppression strategies and antisense oligonucleotides are exciting novel therapeutic options; however, their clinical viability remains to be determined.
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Affiliation(s)
- Ruofan Connie Han
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Lewis E. Fry
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Ariel Kantor
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Kanmin Xue
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Robert E. MacLaren
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, UK
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15
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Mamaeva D, Jazouli Z, DiFrancesco ML, Erkilic N, Dubois G, Hilaire C, Meunier I, Boukhaddaoui H, Kalatzis V. Novel roles for voltage-gated T-type Ca 2+ and ClC-2 channels in phagocytosis and angiogenic factor balance identified in human iPSC-derived RPE. FASEB J 2021; 35:e21406. [PMID: 33724552 DOI: 10.1096/fj.202002754r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/13/2021] [Accepted: 01/19/2021] [Indexed: 01/26/2023]
Abstract
Human-induced pluripotent stem cell (hiPSC)-derived retinal pigment epithelium (RPE) is a powerful tool for pathophysiological studies and preclinical therapeutic screening, as well as a source for clinical cell transplantation. Thus, it must be validated for maturity and functionality to ensure correct data readouts and clinical safety. Previous studies have validated hiPSC-derived RPE as morphologically characteristic of the tissue in the human eye. However, information concerning the expression and functionality of ion channels is still limited. We screened hiPSC-derived RPE for the polarized expression of a panel of L-type (CaV 1.1, CaV 1.3) and T-type (CaV 3.1, CaV 3.3) Ca2+ channels, K+ channels (Maxi-K, Kir4.1, Kir7.1), and the Cl- channel ClC-2 known to be expressed in native RPE. We also tested the roles of these channels in key RPE functions using specific inhibitors. In addition to confirming the native expression profiles and function of certain channels, such as L-type Ca2+ channels, we show for the first time that T-type Ca2+ channels play a role in both phagocytosis and vascular endothelial growth factor (VEGF) secretion. Moreover, we demonstrate that Maxi-K and Kir7.1 channels are involved in the polarized secretion of VEGF and pigment epithelium-derived factor (PEDF). Furthermore, we show a novel localization for ClC-2 channel on the apical side of hiPSC-derived RPE, with an overexpression at the level of fluid-filled domes, and demonstrate that it plays an important role in phagocytosis, as well as VEGF and PEDF secretion. Taken together, hiPSC-derived RPE is a powerful model for advancing fundamental knowledge of RPE functions.
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Affiliation(s)
- Daria Mamaeva
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Zhour Jazouli
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Mattia L DiFrancesco
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Nejla Erkilic
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, Montpellier University, CHU, Montpellier, France
| | - Gregor Dubois
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Cecile Hilaire
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, Montpellier University, CHU, Montpellier, France
| | - Hassan Boukhaddaoui
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
| | - Vasiliki Kalatzis
- Institute for Neurosciences of Montpellier, Inserm, Montpellier University, Montpellier, France
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16
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Zeitz C, Nassisi M, Laurent-Coriat C, Andrieu C, Boyard F, Condroyer C, Démontant V, Antonio A, Lancelot ME, Frederiksen H, Kloeckener-Gruissem B, El-Shamieh S, Zanlonghi X, Meunier I, Roux AF, Mohand-Saïd S, Sahel JA, Audo I. CHM mutation spectrum and disease: An update at the time of human therapeutic trials. Hum Mutat 2021; 42:323-341. [PMID: 33538369 DOI: 10.1002/humu.24174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/21/2020] [Accepted: 01/20/2021] [Indexed: 12/15/2022]
Abstract
Choroideremia is an X-linked inherited retinal disorder (IRD) characterized by the degeneration of retinal pigment epithelium, photoreceptors, choriocapillaris and choroid affecting males with variable phenotypes in female carriers. Unlike other IRD, characterized by a large clinical and genetic heterogeneity, choroideremia shows a specific phenotype with causative mutations in only one gene, CHM. Ongoing gene replacement trials raise further interests in this disorder. We describe here the clinical and genetic data from a French cohort of 45 families, 25 of which carry novel variants, in the context of 822 previously reported choroideremia families. Most of the variants represent loss-of-function mutations with eleven families having large (i.e. ≥6 kb) genomic deletions, 18 small insertions, deletions or insertion deletions, six showing nonsense variants, eight splice site variants and two missense variants likely to affect splicing. Similarly, 822 previously published families carry mostly loss-of-function variants. Recurrent variants are observed worldwide, some of which linked to a common ancestor, others arisen independently in specific CHM regions prone to mutations. Since all exons of CHM may harbor variants, Sanger sequencing combined with quantitative polymerase chain reaction or multiplex ligation-dependent probe amplification experiments are efficient to achieve the molecular diagnosis in patients with typical choroideremia features.
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Affiliation(s)
- Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Marco Nassisi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Camille Andrieu
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France
| | - Fiona Boyard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Vanessa Démontant
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Barbara Kloeckener-Gruissem
- Institute of Medical Molecular Genetics, University of Zurich, Schlieren, Switzerland.,Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Said El-Shamieh
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
| | - Xavier Zanlonghi
- Clinique Pluridisciplinaire Jules Verne, Institut Ophtalmologique de l'Ouest, Nantes, France
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Montpellier, France.,Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Académie des Sciences-Institut de France, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France.,Department of Genetics, UCL-Institute of Ophthalmology, London, UK
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17
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Abbouda A, Avogaro F, Moosajee M, Vingolo EM. Update on Gene Therapy Clinical Trials for Choroideremia and Potential Experimental Therapies. MEDICINA (KAUNAS, LITHUANIA) 2021; 57:64. [PMID: 33445564 PMCID: PMC7826687 DOI: 10.3390/medicina57010064] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/26/2020] [Accepted: 01/07/2021] [Indexed: 12/27/2022]
Abstract
Background and objectives: Choroideremia (CHM) is an X-linked recessive chorioretinal dystrophy caused by mutations involving the CHM gene. Gene therapy has entered late-phase clinical trials, although there have been variable results. This review gives a summary on the outcomes of phase I/II CHM gene therapy trials and describes other potential experimental therapies. Materials and Methods: A Medline (National Library of Medicine, Bethesda, MD, USA) search was performed to identify all articles describing gene therapy treatments available for CHM. Results: Five phase I/II clinical trials that reported subretinal injection of adeno-associated virus Rab escort protein 1 (AAV2.REP1) vector in CHM patients were included. The Oxford study (NCT01461213) included 14 patients; a median gain of 5.5 ± 6.8 SD (-6 min, 18 max) early treatment diabetic retinopathy study (ETDRS) letters was reported. The Tubingen study (NCT02671539) included six patients; only one patient had an improvement of 17 ETDRS letters. The Alberta study (NCT02077361) enrolled six patients, and it reported a minimal vision change, except for one patient who gained 15 ETDRS letters. Six patients were enrolled in the Miami trial (NCT02553135), which reported a median gain of 2 ± 4 SD (-1 min, 10 max) ETDRS letters. The Philadelphia study (NCT02341807) included 10 patients; best corrected visual acuity (BCVA) returned to baseline in all by one-year follow-up, but one patient had -17 ETDRS letters from baseline. Overall, 40 patients were enrolled in trials, and 34 had 2 years of follow-up, with a median gain of 1.5 ± 7.2 SD (-14 min, 18 max) in ETDRS letters. Conclusions: The primary endpoint, BCVA following gene therapy in CHM, showed a marginal improvement with variability between trials. Optimizing surgical technique and pre-, peri-, and post-operative management with immunosuppressants to minimize any adverse ocular inflammatory events could lead to reduced incidence of complications. The ideal therapeutic window needs to be addressed to ensure that the necessary cell types are adequately transduced, minimizing viral toxicity, to prolong long-term transgenic potential. Long-term efficacy will be addressed by ongoing studies.
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Affiliation(s)
| | - Filippo Avogaro
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p.le A. Moro 5, 00185 Rome, Italy;
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK;
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Enzo Maria Vingolo
- Fiorini Hospital Terracina AUSL, 04019 Terracina, Latina, Italy;
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p.le A. Moro 5, 00185 Rome, Italy;
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18
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Carlson-Stevermer J, Das A, Abdeen AA, Fiflis D, Grindel BI, Saxena S, Akcan T, Alam T, Kletzien H, Kohlenberg L, Goedland M, Dombroe MJ, Saha K. Design of efficacious somatic cell genome editing strategies for recessive and polygenic diseases. Nat Commun 2020; 11:6277. [PMID: 33293555 PMCID: PMC7722885 DOI: 10.1038/s41467-020-20065-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/13/2020] [Indexed: 02/06/2023] Open
Abstract
Compound heterozygous recessive or polygenic diseases could be addressed through gene correction of multiple alleles. However, targeting of multiple alleles using genome editors could lead to mixed genotypes and adverse events that amplify during tissue morphogenesis. Here we demonstrate that Cas9-ribonucleoprotein-based genome editors can correct two distinct mutant alleles within a single human cell precisely. Gene-corrected cells in an induced pluripotent stem cell model of Pompe disease expressed the corrected transcript from both corrected alleles, leading to enzymatic cross-correction of diseased cells. Using a quantitative in silico model for the in vivo delivery of genome editors into the developing human infant liver, we identify progenitor targeting, delivery efficiencies, and suppression of imprecise editing outcomes at the on-target site as key design parameters that control the efficacy of various therapeutic strategies. This work establishes that precise gene editing to correct multiple distinct gene variants could be highly efficacious if designed appropriately.
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Affiliation(s)
- Jared Carlson-Stevermer
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Amritava Das
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
| | - Amr A Abdeen
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - David Fiflis
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Benjamin I Grindel
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Shivani Saxena
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Tugce Akcan
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Tausif Alam
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
| | - Heidi Kletzien
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Lucille Kohlenberg
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Madelyn Goedland
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Micah J Dombroe
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Krishanu Saha
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Retina Research Foundation Kathryn and Latimer Murfee Chair, Madison, WI, USA.
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19
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Way CM, Lima Cunha D, Moosajee M. Translational readthrough inducing drugs for the treatment of inherited retinal dystrophies. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2020.1762489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Christopher M Way
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
| | - Dulce Lima Cunha
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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20
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Cehajic Kapetanovic J, Barnard AR, MacLaren RE. Molecular Therapies for Choroideremia. Genes (Basel) 2019; 10:genes10100738. [PMID: 31548516 PMCID: PMC6826983 DOI: 10.3390/genes10100738] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/14/2019] [Accepted: 09/20/2019] [Indexed: 01/03/2023] Open
Abstract
Advances in molecular research have culminated in the development of novel gene-based therapies for inherited retinal diseases. We have recently witnessed several groundbreaking clinical studies that ultimately led to approval of Luxturna, the first gene therapy for an inherited retinal disease. In parallel, international research community has been engaged in conducting gene therapy trials for another more common inherited retinal disease known as choroideremia and with phase III clinical trials now underway, approval of this therapy is poised to follow suit. This chapter discusses new insights into clinical phenotyping and molecular genetic testing in choroideremia with review of molecular mechanisms implicated in its pathogenesis. We provide an update on current gene therapy trials and discuss potential inclusion of female carries in future clinical studies. Alternative molecular therapies are discussed including suitability of CRISPR gene editing, small molecule nonsense suppression therapy and vision restoration strategies in late stage choroideremia.
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Affiliation(s)
- Jasmina Cehajic Kapetanovic
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK; (A.R.B.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Correspondence:
| | - Alun R. Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK; (A.R.B.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK; (A.R.B.); (R.E.M.)
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
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21
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Erkilic N, Gatinois V, Torriano S, Bouret P, Sanjurjo-Soriano C, Luca VD, Damodar K, Cereso N, Puechberty J, Sanchez-Alcudia R, Hamel CP, Ayuso C, Meunier I, Pellestor F, Kalatzis V. A Novel Chromosomal Translocation Identified due to Complex Genetic Instability in iPSC Generated for Choroideremia. Cells 2019; 8:cells8091068. [PMID: 31514470 PMCID: PMC6770680 DOI: 10.3390/cells8091068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 08/28/2019] [Accepted: 09/07/2019] [Indexed: 12/19/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) have revolutionized the study of human diseases as they can renew indefinitely, undergo multi-lineage differentiation, and generate disease-specific models. However, the difficulty of working with iPSCs is that they are prone to genetic instability. Furthermore, genetically unstable iPSCs are often discarded, as they can have unforeseen consequences on pathophysiological or therapeutic read-outs. We generated iPSCs from two brothers of a previously unstudied family affected with the inherited retinal dystrophy choroideremia. We detected complex rearrangements involving chromosomes 12, 20 and/or 5 in the generated iPSCs. Suspecting an underlying chromosomal aberration, we performed karyotype analysis of the original fibroblasts, and of blood cells from additional family members. We identified a novel chromosomal translocation t(12;20)(q24.3;q11.2) segregating in this family. We determined that the translocation was balanced and did not impact subsequent retinal differentiation. We show for the first time that an undetected genetic instability in somatic cells can breed further instability upon reprogramming. Therefore, the detection of chromosomal aberrations in iPSCs should not be disregarded, as they may reveal rearrangements segregating in families. Furthermore, as such rearrangements are often associated with reproductive failure or birth defects, this in turn has important consequences for genetic counseling of family members.
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Affiliation(s)
- Nejla Erkilic
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Vincent Gatinois
- Chromosomal Genetics Unit, Chromostem Platform, CHU, Montpellier, France
| | - Simona Torriano
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Pauline Bouret
- Chromosomal Genetics Unit, Chromostem Platform, CHU, Montpellier, France
| | - Carla Sanjurjo-Soriano
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Valerie De Luca
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Krishna Damodar
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Nicolas Cereso
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
| | - Jacques Puechberty
- Service of Clinical Genetics, Department of Medical Genetics, Rare Diseases and Personalized Medicine, CHU, Montpellier, France
| | - Rocio Sanchez-Alcudia
- Department of Genetics, Institute for Sanitary Investigation, Foundation Jimenez Diaz, 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Christian P Hamel
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
- National Reference Centre for Inherited Sensory Diseases, CHU, 34295 Montpellier, France
| | - Carmen Ayuso
- Department of Genetics, Institute for Sanitary Investigation, Foundation Jimenez Diaz, 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Isabelle Meunier
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France
- University of Montpellier, 34090 Montpellier, France
- National Reference Centre for Inherited Sensory Diseases, CHU, 34295 Montpellier, France
| | - Franck Pellestor
- Chromosomal Genetics Unit, Chromostem Platform, CHU, Montpellier, France
| | - Vasiliki Kalatzis
- Inserm U1051, Institute for Neurosciences of Montpellier, 34091 Montpellier CEDEX 5, France.
- University of Montpellier, 34090 Montpellier, France.
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Vázquez-Domínguez I, Garanto A, Collin RWJ. Molecular Therapies for Inherited Retinal Diseases-Current Standing, Opportunities and Challenges. Genes (Basel) 2019; 10:genes10090654. [PMID: 31466352 PMCID: PMC6770110 DOI: 10.3390/genes10090654] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal diseases (IRDs) are both genetically and clinically highly heterogeneous and have long been considered incurable. Following the successful development of a gene augmentation therapy for biallelic RPE65-associated IRD, this view has changed. As a result, many different therapeutic approaches are currently being developed, in particular a large variety of molecular therapies. These are depending on the severity of the retinal degeneration, knowledge of the pathophysiological mechanism underlying each subtype of IRD, and the therapeutic target molecule. DNA therapies include approaches such as gene augmentation therapy, genome editing and optogenetics. For some genetic subtypes of IRD, RNA therapies and compound therapies have also shown considerable therapeutic potential. In this review, we summarize the current state-of-the-art of various therapeutic approaches, including the pros and cons of each strategy, and outline the future challenges that lie ahead in the combat against IRDs.
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Affiliation(s)
- Irene Vázquez-Domínguez
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands
| | - Alejandro Garanto
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands.
| | - Rob W J Collin
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525GA Nijmegen, The Netherlands.
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Sarkar H, Mitsios A, Smart M, Skinner J, Welch AA, Kalatzis V, Coffey PJ, Dubis AM, Webster AR, Moosajee M. Nonsense-mediated mRNA decay efficiency varies in choroideremia providing a target to boost small molecule therapeutics. Hum Mol Genet 2019; 28:1865-1871. [PMID: 30689859 PMCID: PMC6522067 DOI: 10.1093/hmg/ddz028] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/18/2019] [Accepted: 01/21/2019] [Indexed: 12/15/2022] Open
Abstract
Choroideremia (CHM) is an x-linked recessive chorioretinal dystrophy, with 30% caused by nonsense mutations in the CHM gene resulting in an in-frame premature termination codon (PTC). Nonsense-mediated mRNA decay (NMD) is the cell's natural surveillance mechanism that detects and destroys PTC-containing transcripts, with UPF1 being the central NMD modulator. NMD efficiency can be variable amongst individuals with some transcripts escaping destruction, leading to the production of a truncated non-functional or partially functional protein. Nonsense suppression drugs, such as ataluren, target these transcripts and read-through the PTC, leading to the production of a full length functional protein. Patients with higher transcript levels are considered to respond better to these drugs, as more substrate is available for read-through. Using Quantitative reverse transcription PCR (RT-qPCR), we show that CHM mRNA expression in blood from nonsense mutation CHM patients is 2.8-fold lower than controls, and varies widely amongst patients, with 40% variation between those carrying the same UGA mutation [c.715 C>T; p.(R239*)]. These results indicate that although NMD machinery is at work, efficiency is highly variable and not wholly dependent on mutation position. No significant difference in CHM mRNA levels was seen between two patients' fibroblasts and their induced pluripotent stem cell-derived retinal pigment epithelium. There was no correlation between CHM mRNA expression and genotype, phenotype or UPF1 transcript levels. NMD inhibition with caffeine was shown to restore CHM mRNA transcripts to near wild-type levels. Baseline mRNA levels may provide a prognostic indicator for response to nonsense suppression therapy, and caffeine may be a useful adjunct to enhance treatment efficacy where indicated.
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Affiliation(s)
- Hajrah Sarkar
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
| | - Andreas Mitsios
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Matthew Smart
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
| | - Jane Skinner
- Department of Public Health & Primary Care, Norwich Medical School, University of East Anglia, Norwich, UK
| | - Ailsa A Welch
- Department of Public Health & Primary Care, Norwich Medical School, University of East Anglia, Norwich, UK
| | - Vasiliki Kalatzis
- Inserm U1051, Institute for Neurosciences of Montpellier, Montpellier, Montpellier Cedex, France
| | - Peter J Coffey
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
| | - Adam M Dubis
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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24
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Mitsios A, Dubis AM, Moosajee M. Choroideremia: from genetic and clinical phenotyping to gene therapy and future treatments. Ther Adv Ophthalmol 2018; 10:2515841418817490. [PMID: 30627697 PMCID: PMC6311551 DOI: 10.1177/2515841418817490] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/05/2018] [Indexed: 11/15/2022] Open
Abstract
Choroideremia is an X-linked inherited chorioretinal dystrophy leading to blindness by late adulthood. Choroideremia is caused by mutations in the CHM gene which encodes Rab escort protein 1 (REP1), an ubiquitously expressed protein involved in intracellular trafficking and prenylation activity. The exact site of pathogenesis remains unclear but results in degeneration of the photoreceptors, retinal pigment epithelium and choroid. Animal and stem cell models have been used to study the molecular defects in choroideremia and test effectiveness of treatment interventions. Natural history studies of choroideremia have provided additional insight into the clinical phenotype of the condition and prepared the way for clinical trials aiming to investigate the safety and efficacy of suitable therapies. In this review, we provide a summary of the current knowledge on the genetics, pathophysiology, clinical features and therapeutic strategies that might become available for choroideremia in the future, including gene therapy, stem cell treatment and small-molecule drugs with nonsense suppression action.
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Affiliation(s)
- Andreas Mitsios
- Institute of Ophthalmology, University College London, London, UK
| | - Adam M Dubis
- Institute of Ophthalmology, University College London, London, UK
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London, UK
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25
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Novel CHM mutations in Polish patients with choroideremia - an orphan disease with close perspective of treatment. Orphanet J Rare Dis 2018; 13:221. [PMID: 30541579 PMCID: PMC6291982 DOI: 10.1186/s13023-018-0965-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/27/2018] [Indexed: 11/27/2022] Open
Abstract
Background Choroideremia (CHM) is a rare X-linked recessive retinal dystrophy characterized by progressive chorioretinal degeneration in the males affected. The symptoms include night blindness in childhood, progressive peripheral vision loss and total blindness in the late stages. The disease is caused by mutations in the CHM gene encoding Rab Escort Protein 1 (REP-1). The aim of the study was to identify the molecular basis of choroideremia in five families of Polish origin. Methods Six male patients from five unrelated families of Polish ethnicity, who were clinically diagnosed with choroideremia, were examined in this study. An ophthalmologic examination performed in all the probands included: best-corrected visual acuity, slit-lamp examination, funduscopy, fluorescein angiography and perimetry. The entire coding region encompassing 15 exons and the flanking intronic sequences of the CHM gene were amplified with PCR and directly sequenced in all the patients. Results Five variants in the CHM gene were identified in the five families examined. Two of the variants were new: c.1175dupT and c.83C > G, while three had been previously reported. Conclusions This study provides the first molecular genetic characteristics of patients with choroideremia from the previously unexplored Polish population.
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Vaché C, Torriano S, Faugère V, Erkilic N, Baux D, Garcia-Garcia G, Hamel CP, Meunier I, Zanlonghi X, Koenig M, Kalatzis V, Roux AF. Pathogenicity of novel atypical variants leading to choroideremia as determined by functional analyses. Hum Mutat 2018; 40:31-35. [DOI: 10.1002/humu.23671] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Christel Vaché
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Simona Torriano
- Institut des Neurosciences de Montpellier; INSERM; Université de Montpellier; Montpellier France
| | - Valérie Faugère
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Nejla Erkilic
- Institut des Neurosciences de Montpellier; INSERM; Université de Montpellier; Montpellier France
| | - David Baux
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Gema Garcia-Garcia
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Christian P. Hamel
- Institut des Neurosciences de Montpellier; INSERM; Université de Montpellier; Montpellier France
- Centre de Référence Maladies Sensorielles Génétiques; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Isabelle Meunier
- Institut des Neurosciences de Montpellier; INSERM; Université de Montpellier; Montpellier France
- Centre de Référence Maladies Sensorielles Génétiques; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Xavier Zanlonghi
- Centre de Compétence Maladie Rares; Clinique Pluridisciplinaire Jules Verne; Nantes France
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
| | - Vasiliki Kalatzis
- Institut des Neurosciences de Montpellier; INSERM; Université de Montpellier; Montpellier France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire; CHU de Montpellier; Université de Montpellier; Montpellier France
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