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Reis LM, Seese SE, Costakos D, Semina EV. Congenital anterior segment ocular disorders: Genotype-phenotype correlations and emerging novel mechanisms. Prog Retin Eye Res 2024; 102:101288. [PMID: 39097141 DOI: 10.1016/j.preteyeres.2024.101288] [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: 03/30/2023] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/05/2024]
Abstract
Development of the anterior segment of the eye requires reciprocal sequential interactions between the arising tissues, facilitated by numerous genetic factors. Disruption of any of these processes results in congenital anomalies in the affected tissue(s) leading to anterior segment disorders (ASD) including aniridia, Axenfeld-Rieger anomaly, congenital corneal opacities (Peters anomaly, cornea plana, congenital primary aphakia), and primary congenital glaucoma. Current understanding of the genetic factors involved in ASD remains incomplete, with approximately 50% overall receiving a genetic diagnosis. While some genes are strongly associated with a specific clinical diagnosis, the majority of known factors are linked with highly variable phenotypic presentations, with pathogenic variants in FOXC1, CYP1B1, and PITX2 associated with the broadest spectrum of ASD conditions. This review discusses typical clinical presentations including associated systemic features of various forms of ASD; the latest functional data and genotype-phenotype correlations related to 25 ASD factors including newly identified genes; promising novel candidates; and current and emerging treatments for these complex conditions. Recent developments of interest in the genetics of ASD include identification of phenotypic expansions for several factors, discovery of multiple modes of inheritance for some genes, and novel mechanisms including a growing number of non-coding variants and alleles affecting specific domains/residues and requiring further studies.
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Affiliation(s)
- Linda M Reis
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
| | - Sarah E Seese
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
| | - Deborah Costakos
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
| | - Elena V Semina
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA; Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin and Children's Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA; Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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2
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Xu F, Zheng C, Xu W, Zhang S, Liu S, Chen X, Yao K. Breaking genetic shackles: The advance of base editing in genetic disorder treatment. Front Pharmacol 2024; 15:1364135. [PMID: 38510648 PMCID: PMC10953296 DOI: 10.3389/fphar.2024.1364135] [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: 01/01/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
The rapid evolution of gene editing technology has markedly improved the outlook for treating genetic diseases. Base editing, recognized as an exceptionally precise genetic modification tool, is emerging as a focus in the realm of genetic disease therapy. We provide a comprehensive overview of the fundamental principles and delivery methods of cytosine base editors (CBE), adenine base editors (ABE), and RNA base editors, with a particular focus on their applications and recent research advances in the treatment of genetic diseases. We have also explored the potential challenges faced by base editing technology in treatment, including aspects such as targeting specificity, safety, and efficacy, and have enumerated a series of possible solutions to propel the clinical translation of base editing technology. In conclusion, this article not only underscores the present state of base editing technology but also envisions its tremendous potential in the future, providing a novel perspective on the treatment of genetic diseases. It underscores the vast potential of base editing technology in the realm of genetic medicine, providing support for the progression of gene medicine and the development of innovative approaches to genetic disease therapy.
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Affiliation(s)
- Fang Xu
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Caiyan Zheng
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Weihui Xu
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Shiyao Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Shanshan Liu
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Xiaopeng Chen
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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3
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Duncan MK, Daruich A, Valleix S, Bremond-Gignac D. Reduction of lens size in PAX6-related aniridia. Exp Eye Res 2024; 238:109746. [PMID: 38056551 PMCID: PMC10843565 DOI: 10.1016/j.exer.2023.109746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023]
Abstract
Heterozygous mutation of PAX6 in humans leads to congenital aniridia (OMIM 106210) which is typified by congenital iris and foveal defects, and later onset glaucoma, aniridic keratopathy, and cataract. Mice heterozygous for Pax6 mutations phenocopy many aspects of aniridia including the iris defects, keratopathy and cataract, although Pax6 mutant mice have small lenses, a phenotype which is not typically reported in human aniridia, perhaps due to difficulties in measuring lens diameter during typical ophthalmic examinations as the lens periphery is shielded by the iris. In order to overcome this, records of patients diagnosed with congenital aniridia between April 2015 and May 2021 at the Necker-Enfants Malades Hospital, and genetically confirmed with a disease-causing PAX6 variant, were retrospectively reviewed for those with normal axial length whose iris defects allowed visualization of the lens margins and corneal diameter to allow calculation of a lens/corneal diameter ratio. This value was compared with values obtained from a cohort of patients with Sjödell grade IV oculocutaneous albinism type 1 (OCA1; OMIM 203100) which allowed visualization of the lens periphery via iris transillumination. This analysis revealed that patients with congenital aniridia had a significantly lower lens/corneal ratio when compared to those with albinism, suggesting that humans haploinsufficient for PAX6, like mice, rats, frogs, and zebrafish, exhibit reductions in lens size.
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Affiliation(s)
- Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA.
| | - Alejandra Daruich
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Sophie Valleix
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP Centre, Paris, Université de Paris Cité, Fédération de Génétique et de Médecine Génomique, Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris, Cedex 14, France
| | - Dominique Bremond-Gignac
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
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Gour A, Tibrewal S, Garg A, Vohra M, Ratna R, Sangwan VS. New horizons in aniridia management: Clinical insights and therapeutic advances. Taiwan J Ophthalmol 2023; 13:467-478. [PMID: 38249501 PMCID: PMC10798387 DOI: 10.4103/tjo.tjo-d-23-00140] [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: 09/14/2023] [Accepted: 10/11/2023] [Indexed: 01/23/2024] Open
Abstract
Congenital aniridia is a rare genetic eye disorder characterized by the complete or partial absence of the iris from birth. Various theories and animal models have been proposed to understand and explain the pathogenesis of aniridia. In the majority of cases, aniridia is caused by a mutation in the PAX6 gene, which affects multiple structures within the eye. Treating these ocular complications is challenging and carries a high risk of side effects. However, emerging approaches for the treatment of aniridia-associated keratopathy, iris abnormalities, cataract abnormalities, and foveal hypoplasia show promise for improved outcomes. Genetic counseling plays a very important role to make informed choices. We also provide an overview of the newer diagnostic and therapeutic approaches such as next generation sequencing, gene therapy, in vivo silencing, and miRNA modulation.
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Affiliation(s)
- Abha Gour
- Department of Cornea and Anterior Segment, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
- Eicher-Shroff Centre for Stem Cell Research, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
| | - Shailaja Tibrewal
- Department of Pediatric Ophthalmology and Strabismus, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
- Department of Ocular Genetics, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
| | - Aastha Garg
- Department of Cornea and Anterior Segment, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
| | - Mehak Vohra
- Eicher-Shroff Centre for Stem Cell Research, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
| | - Ria Ratna
- Department of Ocular Genetics, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
| | - Virender Singh Sangwan
- Department of Cornea and Anterior Segment, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
- Eicher-Shroff Centre for Stem Cell Research, Dr. Shroff’s Charity Eye Hospital, New Delhi, India
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5
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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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6
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van Velthoven AJH, Utheim TP, Notara M, Bremond-Gignac D, Figueiredo FC, Skottman H, Aberdam D, Daniels JT, Ferrari G, Grupcheva C, Koppen C, Parekh M, Ritter T, Romano V, Ferrari S, Cursiefen C, Lagali N, LaPointe VLS, Dickman MM. Future directions in managing aniridia-associated keratopathy. Surv Ophthalmol 2023; 68:940-956. [PMID: 37146692 DOI: 10.1016/j.survophthal.2023.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 04/19/2023] [Accepted: 04/24/2023] [Indexed: 05/07/2023]
Abstract
Congenital aniridia is a panocular disorder that is typically characterized by iris hypoplasia and aniridia-associated keratopathy (AAK). AAK results in the progressive loss of corneal transparency and thereby loss of vision. Currently, there is no approved therapy to delay or prevent its progression, and clinical management is challenging because of phenotypic variability and high risk of complications after interventions; however, new insights into the molecular pathogenesis of AAK may help improve its management. Here, we review the current understanding about the pathogenesis and management of AAK. We highlight the biological mechanisms involved in AAK development with the aim to develop future treatment options, including surgical, pharmacological, cell therapies, and gene therapies.
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Affiliation(s)
- Arianne J H van Velthoven
- MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands; University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands
| | - Tor P Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
| | - Maria Notara
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Dominique Bremond-Gignac
- Ophthalmology Department, University Hospital Necker-Enfants Malades, APHP, Paris Cité University, Paris, France; Centre de Recherche des Cordeliers, Sorbonne Paris Cité University, Paris, France
| | - Francisco C Figueiredo
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK; Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Heli Skottman
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Daniel Aberdam
- Centre de Recherche des Cordeliers, Sorbonne Paris Cité University, Paris, France
| | | | - Giulio Ferrari
- Cornea and Ocular Surface Unit, Eye Repair Lab, San Raffaele Hospital, Milan, Italy
| | - Christina Grupcheva
- Department of Ophthalmology and Visual Sciences, Medical University of Varna, Varna, Bulgaria
| | - Carina Koppen
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Mohit Parekh
- Schepens Eye Research Institute, Harvard Medical School, Boston, MA, USA
| | - Thomas Ritter
- Regenerative Medicine Institute, University of Galway, Galway, Ireland
| | - Vito Romano
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Brescia, Italy
| | | | - Claus Cursiefen
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Neil Lagali
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Vanessa L S LaPointe
- MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands
| | - Mor M Dickman
- MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, the Netherlands; University Eye Clinic Maastricht, Maastricht University Medical Center+, Maastricht, the Netherlands
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Adair BA, Korecki AJ, Djaksigulova D, Wagner PK, Chiu NY, Lam SL, Lengyell TC, Leavitt BR, Simpson EM. ABE8e Corrects Pax6-Aniridic Variant in Humanized Mouse ESCs and via LNPs in Ex Vivo Cortical Neurons. Ophthalmol Ther 2023; 12:2049-2068. [PMID: 37210469 PMCID: PMC10287867 DOI: 10.1007/s40123-023-00729-6] [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: 03/12/2023] [Accepted: 04/27/2023] [Indexed: 05/22/2023] Open
Abstract
INTRODUCTION Aniridia is a rare congenital vision-loss disease caused by heterozygous variants in the PAX6 gene. There is no vision-saving therapy, but one exciting approach is to use CRISPR/Cas9 to permanently correct the causal genomic variants. Preclinical studies to develop such a therapy in animal models face the challenge of showing efficacy when binding human DNA. Thus, we hypothesized that a CRISPR gene therapy can be developed and optimized in humanized mouse embryonic stem cells (ESCs) that will be able to distinguish between an aniridia patient variant and nonvariant chromosome and lay the foundation for human therapy. METHODS To answer the challenge of binding human DNA, we proposed the "CRISPR Humanized Minimally Mouse Models" (CHuMMMs) strategy. Thus, we minimally humanized Pax6 exon 9, the location of the most common aniridia variant c.718C > T. We generated and characterized a nonvariant CHuMMMs mouse, and a CHuMMMs cell-based disease model, in which we tested five CRISPR enzymes for therapeutic efficacy. We then delivered the therapy via lipid nanoparticles (LNPs) to alter a second variant in ex vivo cortical primary neurons. RESULTS We successfully established a nonvariant CHuMMMs mouse and three novel CHuMMMs aniridia cell lines. We showed that humanization did not disrupt Pax6 function in vivo, as the mouse showed no ocular phenotype. We developed and optimized a CRISPR therapeutic strategy for aniridia in the in vitro system, and found that the base editor, ABE8e, had the highest correction of the patient variant at 76.8%. In the ex vivo system, the LNP-encapsulated ABE8e ribonucleoprotein (RNP) complex altered the second patient variant and rescued 24.8% Pax6 protein expression. CONCLUSION We demonstrated the usefulness of the CHuMMMs approach, and showed the first genomic editing by ABE8e encapsulated as an LNP-RNP. Furthermore, we laid the foundation for translation of the proposed CRISPR therapy to preclinical mouse studies and eventually patients with aniridia.
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Affiliation(s)
- Bethany A Adair
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Andrea J Korecki
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Diana Djaksigulova
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | | | - Nina Y Chiu
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Siu Ling Lam
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Tess C Lengyell
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
- Incisive Genetics Inc., Vancouver, BC, Canada
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada.
- Department of Medical Genetics, The University of British Columbia, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada.
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Daruich A, Duncan M, Robert MP, Lagali N, Semina EV, Aberdam D, Ferrari S, Romano V, des Roziers CB, Benkortebi R, De Vergnes N, Polak M, Chiambaretta F, Nischal KK, Behar-Cohen F, Valleix S, Bremond-Gignac D. Congenital aniridia beyond black eyes: From phenotype and novel genetic mechanisms to innovative therapeutic approaches. Prog Retin Eye Res 2023; 95:101133. [PMID: 36280537 PMCID: PMC11062406 DOI: 10.1016/j.preteyeres.2022.101133] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Congenital PAX6-aniridia, initially characterized by the absence of the iris, has progressively been shown to be associated with other developmental ocular abnormalities and systemic features making congenital aniridia a complex syndromic disorder rather than a simple isolated disease of the iris. Moreover, foveal hypoplasia is now recognized as a more frequent feature than complete iris hypoplasia and a major visual prognosis determinant, reversing the classical clinical picture of this disease. Conversely, iris malformation is also a feature of various anterior segment dysgenesis disorders caused by PAX6-related developmental genes, adding a level of genetic complexity for accurate molecular diagnosis of aniridia. Therefore, the clinical recognition and differential genetic diagnosis of PAX6-related aniridia has been revealed to be much more challenging than initially thought, and still remains under-investigated. Here, we update specific clinical features of aniridia, with emphasis on their genotype correlations, as well as provide new knowledge regarding the PAX6 gene and its mutational spectrum, and highlight the beneficial utility of clinically implementing targeted Next-Generation Sequencing combined with Whole-Genome Sequencing to increase the genetic diagnostic yield of aniridia. We also present new molecular mechanisms underlying aniridia and aniridia-like phenotypes. Finally, we discuss the appropriate medical and surgical management of aniridic eyes, as well as innovative therapeutic options. Altogether, these combined clinical-genetic approaches will help to accelerate time to diagnosis, provide better determination of the disease prognosis and management, and confirm eligibility for future clinical trials or genetic-specific therapies.
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Affiliation(s)
- Alejandra Daruich
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Melinda Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Matthieu P Robert
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris Cité University, Paris, France
| | - Neil Lagali
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Faculty of Medicine, Linköping University, 581 83, Linköping, Sweden; Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
| | - Elena V Semina
- Department of Pediatrics, Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI, 53226, USA
| | - Daniel Aberdam
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Stefano Ferrari
- Fondazione Banca degli Occhi del Veneto, Via Paccagnella 11, Venice, Italy
| | - Vito Romano
- Department of Medical and Surgical Specialties, Radiolological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Italy
| | - Cyril Burin des Roziers
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Rabia Benkortebi
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Nathalie De Vergnes
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Michel Polak
- Pediatric Endocrinology, Gynecology and Diabetology, Hôpital Universitaire Necker Enfants Malades, AP-HP, Paris Cité University, INSERM U1016, Institut IMAGINE, France
| | | | - Ken K Nischal
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Francine Behar-Cohen
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Sophie Valleix
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Dominique Bremond-Gignac
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France.
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9
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Neuhann TM, Neuhann L. [Human genetic diagnostics in hereditary eye diseases : What does the ophthalmologist need to know]. DIE OPHTHALMOLOGIE 2023:10.1007/s00347-023-01878-6. [PMID: 37266672 DOI: 10.1007/s00347-023-01878-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
Hereditary eye disorders can affect all ocular structures and can be accompanied by structural malformations (e.g. coloboma) or functional disorders (e.g. retinal dystrophy). Ocular phenotypes can also be the presenting symptom of many complex syndromic disorders. The majority of hereditary eye disorders are extremely heterogeneous but can be routinely diagnosed by modern high-throughput sequencing technologies. Molecular testing is highly important not only in in the evaluation of differential diagnoses but is also of increasing relevance due to individual treatment options.
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Affiliation(s)
- Teresa M Neuhann
- MGZ - Medizinisch genetisches Zentrum, Bayerstr. 3-5, 80335, München, Deutschland.
| | - Lukas Neuhann
- MVZ Prof. Neuhann, Helene-Weber-Allee 19, 80637, München, Deutschland
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10
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Abdolkarimi D, Cunha DL, Lahne1 M, Moosajee M. PAX6 disease models for aniridia. Indian J Ophthalmol 2022; 70:4119-4129. [PMID: 36453299 PMCID: PMC9940591 DOI: 10.4103/ijo.ijo_316_22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/01/2022] [Accepted: 08/10/2022] [Indexed: 12/12/2022] Open
Abstract
Aniridia is a pan-ocular genetic developmental eye disorder characterized by complete or partial iris and foveal hypoplasia, for which there is no treatment currently. Progressive sight loss can arise from cataracts, glaucoma, and aniridia-related keratopathy, which can be managed conservatively or through surgical intervention. The vast majority of patients harbor heterozygous mutations involving the PAX6 gene, which is considered the master transcription factor of early eye development. Over the past decades, several disease models have been investigated to gain a better understanding of the molecular pathophysiology, including several mouse and zebrafish strains and, more recently, human-induced pluripotent stem cells (hiPSCs) derived from aniridia patients. The latter provides a more faithful cellular system to study early human eye development. This review outlines the main aniridia-related animal and cellular models used to study aniridia and highlights the key discoveries that are bringing us closer to a therapy for patients.
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Affiliation(s)
| | - Dulce Lima Cunha
- UCL Institute of Ophthalmology, London, UK
- Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, Netherlands
| | | | - Mariya Moosajee
- 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
- The Francis Crick Institute, London, UK
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11
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Mirjalili Mohanna SZ, Djaksigulova D, Hill AM, Wagner PK, Simpson EM, Leavitt BR. LNP-mediated delivery of CRISPR RNP for wide-spread in vivo genome editing in mouse cornea. J Control Release 2022; 350:401-413. [PMID: 36029893 DOI: 10.1016/j.jconrel.2022.08.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 01/02/2023]
Abstract
CRISPR/Cas9-based genome-editing therapies are poised to change the clinical outcome for many diseases with validated therapeutic targets awaiting an appropriate delivery system. Recent advances in lipid nanoparticle (LNP) technology make them an attractive platform for the delivery of various forms of CRISPR/Cas9, including the efficient and transient Cas9/gRNA ribonucleoprotein (RNP) complexes. In this study, we initially tested our novel LNP platform by delivering pre-complexed RNPs and template DNA to cultured mouse cortical neurons, and obtained successful ex vivo genome editing. We then directly injected LNP-packaged RNPs and DNA template into the mouse cornea to evaluate in vivo delivery. For the first time, we demonstrated wide-spread genome editing in the cornea using our LNP-RNPs. The ability of our LNPs to transfect the cornea highlights the potential of our novel delivery platform to be used in CRISPR/Cas9-based genome editing therapies of corneal diseases.
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Affiliation(s)
- Seyedeh Zeinab Mirjalili Mohanna
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
| | - Diana Djaksigulova
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC, Canada
| | | | | | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada.
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC, Canada; Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada; Incisive Genetics Inc., Vancouver, BC, Canada
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12
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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: 11] [Impact Index Per Article: 5.5] [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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13
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Burgess FR, Hall HN, Megaw R. Emerging Gene Manipulation Strategies for the Treatment of Monogenic Eye Disease. Asia Pac J Ophthalmol (Phila) 2022; 11:380-391. [PMID: 36041151 DOI: 10.1097/apo.0000000000000545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/27/2022] [Indexed: 12/15/2022] Open
Abstract
Genetic eye diseases, representing a wide spectrum of simple and complex conditions, are one of the leading causes of visual loss in children and working adults, and progress in the field has led to changes in disease investigation, diagnosis, and management. The past 15 years have seen the emergence of novel therapies for these previously untreatable conditions to the extent that we now have a licensed therapy for one form of genetic eye disease and many more in clinical trial. This is a systematic review of published and ongoing clinical trials of gene therapies for monogenic eye diseases. Databases of clinical trials and the published literature were searched for interventional studies of gene therapies for eye diseases. Standard methodological procedures were used to assess the relevance of search results. A total of 59 registered clinical trials are referenced, showing the significant level of interest in the potential for translation of these therapies from bench to bedside. The breadth of therapy design is encouraging, providing multiple possible therapeutic mechanisms. Some fundamental questions regarding gene therapy for genetic eye diseases remain, such as optimal dosing, the relative benefits of adeno-associated virus (AAV)-packaging and the potential for a significant inflammatory response to the therapy itself. As a result, despite the promise of the eye as a target, it has proven difficult to deliver clinically effective gene therapies to the eye. Despite setbacks, the licensing of Luxturna (voretigene neparvovec, Novartis) for the treatment of RPE65-mediated Leber congenital amaurosis (LCA) is a major advance in efforts to treat these rare, but devastating, causes of visual loss.
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Affiliation(s)
- Frederick R Burgess
- Princess Alexandra Eye Pavilion, NHS Lothian, UK
- Ophthalmology Department, School of Medicine, University of St Andrews, UK
| | - Hildegard Nikki Hall
- Princess Alexandra Eye Pavilion, NHS Lothian, UK
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, UK
| | - Roly Megaw
- Princess Alexandra Eye Pavilion, NHS Lothian, UK
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, UK
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14
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Cole JD, McHaney KM, Rabiee B, Gao J, Rodriguez C, Miller DA, Liu M, Grannonico M, Norat P, Zhang HF, Djalilian AR, Liu X. Long-term retinal protection by MEK inhibition in Pax6 haploinsufficiency mice. Exp Eye Res 2022; 218:109012. [PMID: 35245513 PMCID: PMC9050935 DOI: 10.1016/j.exer.2022.109012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/21/2022] [Accepted: 02/22/2022] [Indexed: 11/26/2022]
Abstract
Aniridia is a panocular condition characterized by impaired eye development and vision, which is mainly due to the haploinsufficiency of the paired-box-6 (PAX6) gene. Like what is seen in aniridia patients, Pax6-deficient mice Pax6Sey-Neu/+ exhibit a varied degree of ocular damage and impaired vision. Our previous studies showed that these phenotypes were partially rescued by PD0325901, a mitogen-activated protein kinase kinase (MEK or MAP2K) inhibitor. In this study, we assessed the long-term efficacy of PD0325901 treatment in retinal health and visual behavior. At about one year after the postnatal treatment with PD0325901, Pax6Sey-Neu/+ mice showed robust improvements in retina size and visual acuity, and the elevated intraocular pressure (IOP) was also alleviated, compared to age-matched mice treated with vehicles only. Moreover, the Pax6Sey-Neu/+ eyes showed disorganized retinal ganglion cell (RGC) axon bundles and retinal layers, which we termed as hotspots. We found that the PD treatment reduced the number and size of hotspots in the Pax6Sey-Neu/+ retinas. Taken together, our results suggest that PD0325901 may serve as an efficacious intervention in protecting retina and visual function in aniridia-afflicted subjects.
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Affiliation(s)
- James D Cole
- Department of Biology, University of Virginia, Charlottesville, VA, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | - Kara M McHaney
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Behnam Rabiee
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA; Department of Ophthalmology, Nazareth Hospital, Philadelphia, PA, USA
| | - Jingyi Gao
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Carlos Rodriguez
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Mingna Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Pedro Norat
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Ali R Djalilian
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA.
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA; Department of Psychology, University of Virginia, Charlottesville, VA, USA; Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, USA.
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15
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Bezzerri V, Lentini L, Api M, Busilacchi EM, Cavalieri V, Pomilio A, Diomede F, Pegoraro A, Cesaro S, Poloni A, Pace A, Trubiani O, Lippi G, Pibiri I, Cipolli M. Novel Translational Read-through-Inducing Drugs as a Therapeutic Option for Shwachman-Diamond Syndrome. Biomedicines 2022; 10:biomedicines10040886. [PMID: 35453634 PMCID: PMC9024944 DOI: 10.3390/biomedicines10040886] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/03/2022] [Accepted: 04/06/2022] [Indexed: 02/01/2023] Open
Abstract
Shwachman-Diamond syndrome (SDS) is one of the most commonly inherited bone marrow failure syndromes (IBMFS). In SDS, bone marrow is hypocellular, with marked neutropenia. Moreover, SDS patients have a high risk of developing myelodysplastic syndrome (MDS), which in turn increases the risk of acute myeloid leukemia (AML) from an early age. Most SDS patients are heterozygous for the c.183-184TA>CT (K62X) SBDS nonsense mutation. Fortunately, a plethora of translational read-through inducing drugs (TRIDs) have been developed and tested for several rare inherited diseases due to nonsense mutations so far. The authors previously demonstrated that ataluren (PTC124) can restore full-length SBDS protein expression in bone marrow stem cells isolated from SDS patients carrying the nonsense mutation K62X. In this study, the authors evaluated the effect of a panel of ataluren analogues in restoring SBDS protein resynthesis and function both in hematological and non-hematological SDS cells. Besides confirming that ataluren can efficiently induce SBDS protein re-expression in SDS cells, the authors found that another analogue, namely NV848, can restore full-length SBDS protein synthesis as well, showing very low toxicity in zebrafish. Furthermore, NV848 can improve myeloid differentiation in bone marrow hematopoietic progenitors, enhancing neutrophil maturation and reducing the number of dysplastic granulocytes in vitro. Therefore, these findings broaden the possibilities of developing novel therapeutic options in terms of nonsense mutation suppression for SDS. Eventually, this study may act as a proof of concept for the development of similar approaches for other IBMFS caused by nonsense mutations.
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Affiliation(s)
- Valentino Bezzerri
- Cystic Fibrosis Center of Verona, Azienda Ospedaliera Universitaria Integrata, 37126 Verona, Italy; (V.B.); (A.P.)
| | - Laura Lentini
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), University of Palermo, 90128 Palermo, Italy; (L.L.); (V.C.); (A.P.); (I.P.)
| | - Martina Api
- Cystic Fibrosis Center of Ancona, Azienda Ospedaliero Universitaria Ospedali Riuniti, 60126 Ancona, Italy;
| | - Elena Marinelli Busilacchi
- Hematology Clinic, Università Politecnica delle Marche, AOU Ospedali Riuniti, 60126 Ancona, Italy; (E.M.B.); (A.P.)
| | - Vincenzo Cavalieri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), University of Palermo, 90128 Palermo, Italy; (L.L.); (V.C.); (A.P.); (I.P.)
- Zebrafish Laboratory, Advanced Technologies Network (ATeN) Center, University of Palermo, 90128 Palermo, Italy
| | - Antonella Pomilio
- Department of Medical, Oral and Biotechnological Sciences, G. D’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy;
| | - Francesca Diomede
- Dipartimento di Tecnologie Innovative in Medicina e Odontoiatria, G. D’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (F.D.); (O.T.)
| | - Anna Pegoraro
- Cystic Fibrosis Center of Verona, Azienda Ospedaliera Universitaria Integrata, 37126 Verona, Italy; (V.B.); (A.P.)
| | - Simone Cesaro
- Unit of Pediatric Hematology Oncology, Azienda Ospedaliera Universitaria Integrata, 37126 Verona, Italy;
| | - Antonella Poloni
- Hematology Clinic, Università Politecnica delle Marche, AOU Ospedali Riuniti, 60126 Ancona, Italy; (E.M.B.); (A.P.)
| | - Andrea Pace
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), University of Palermo, 90128 Palermo, Italy; (L.L.); (V.C.); (A.P.); (I.P.)
| | - Oriana Trubiani
- Dipartimento di Tecnologie Innovative in Medicina e Odontoiatria, G. D’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (F.D.); (O.T.)
| | - Giuseppe Lippi
- Section of Clinical Biochemistry, University of Verona, 37126 Verona, Italy;
| | - Ivana Pibiri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), University of Palermo, 90128 Palermo, Italy; (L.L.); (V.C.); (A.P.); (I.P.)
| | - Marco Cipolli
- Cystic Fibrosis Center of Verona, Azienda Ospedaliera Universitaria Integrata, 37126 Verona, Italy; (V.B.); (A.P.)
- Correspondence: ; Tel.: +39-045-812-2293
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16
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Beryozkin A, Samanta A, Gopalakrishnan P, Khateb S, Banin E, Sharon D, Nagel-Wolfrum K. Translational Read-Through Drugs (TRIDs) Are Able to Restore Protein Expression and Ciliogenesis in Fibroblasts of Patients with Retinitis Pigmentosa Caused by a Premature Termination Codon in FAM161A. Int J Mol Sci 2022; 23:ijms23073541. [PMID: 35408898 PMCID: PMC8998412 DOI: 10.3390/ijms23073541] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023] Open
Abstract
Ataluren and Gentamicin are translational readthrough drugs (TRIDs) that induce premature termination codon (PTC) readthrough, resulting in the production of full-length proteins that usually harbor a single missense substitution. FAM161A is a ciliary protein which is expressed in photoreceptors, and pathogenic variants in this gene cause retinitis pigmentosa (RP). Applying TRIDs on fibroblasts from RP patients due to PTC in the FAM161A (p.Arg523*) gene may uncover whether TRIDs can restore expression, localization and function of this protein. Fibroblasts from six patients and five age-matched controls were starved prior to treatment with ataluren or gentamicin, and later FAM161A expression, ciliogenesis and cilia length were analyzed. In contrast to control cells, fibroblasts of patients did not express the FAM161A protein, showed a lower percentage of ciliated cells and grew shorter cilia after starvation. Ataluren and Gentamicin treatment were able to restore FAM161A expression, localization and co-localization with α-tubulin. Ciliogenesis and cilia length were restored following Ataluren treatment almost up to a level which was observed in control cells. Gentamicin was less efficient in ciliogenesis compared to Ataluren. Our results provide a proof-of-concept that PTCs in FAM161A can be effectively suppressed by Ataluren or Gentamicin, resulting in a full-length functional protein.
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Affiliation(s)
- Avigail Beryozkin
- Hadassah Medical Center, Department of Ophthalmology, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (A.B.); (P.G.); (S.K.); (E.B.); (D.S.)
| | - Ananya Samanta
- Institute of Molecular Physiology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany;
- Institute of Development Biology and Neurobiology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - Prakadeeswari Gopalakrishnan
- Hadassah Medical Center, Department of Ophthalmology, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (A.B.); (P.G.); (S.K.); (E.B.); (D.S.)
| | - Samer Khateb
- Hadassah Medical Center, Department of Ophthalmology, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (A.B.); (P.G.); (S.K.); (E.B.); (D.S.)
| | - Eyal Banin
- Hadassah Medical Center, Department of Ophthalmology, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (A.B.); (P.G.); (S.K.); (E.B.); (D.S.)
| | - Dror Sharon
- Hadassah Medical Center, Department of Ophthalmology, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (A.B.); (P.G.); (S.K.); (E.B.); (D.S.)
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany;
- Institute of Development Biology and Neurobiology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
- Correspondence:
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Zhao J, Li Z, Puri R, Liu K, Nunez I, Chen L, Zheng S. Molecular profiling of individual FDA-approved clinical drugs identifies modulators of nonsense-mediated mRNA decay. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 27:304-318. [PMID: 35024243 PMCID: PMC8718828 DOI: 10.1016/j.omtn.2021.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 12/07/2021] [Indexed: 12/12/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) degrades transcripts with premature stop codons. Given the prevalence of nonsense single nucleotide polymorphisms (SNPs) in the general population, it is urgent to catalog the effects of clinically approved drugs on NMD activity: any interference could alter the expression of nonsense SNPs, inadvertently inducing adverse effects. This risk is higher for patients with disease-causing nonsense mutations or an illness linked to dysregulated nonsense transcripts. On the other hand, hundreds of disorders are affected by cellular NMD efficiency and may benefit from NMD-modulatory drugs. Here, we profiled individual FDA-approved drugs for their impact on cellular NMD efficiency using a sensitive method that directly probes multiple endogenous NMD targets for a robust readout of NMD modulation. We found most FDA-approved drugs cause unremarkable effects on NMD, while many elicit clear transcriptional responses. Besides several potential mild NMD modulators, the anticancer drug homoharringtonine (HHT or omacetaxine mepesuccinate) consistently upregulates various endogenous NMD substrates in a dose-dependent manner in multiple cell types. We further showed translation inhibition mediates HHT's NMD effect. In summary, many FDA drugs induce transcriptional changes, and a few impact global NMD, and direct measurement of endogenous NMD substrate expression is robust to monitor cellular NMD.
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Affiliation(s)
- Jingrong Zhao
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
| | - Zhelin Li
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
| | - Ruchira Puri
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
| | - Kelvin Liu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
| | - Israel Nunez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
| | - Liang Chen
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Sika Zheng
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 91709, USA
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18
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Thompson B, Chen Y, Davidson EA, Garcia-Milian R, Golla JP, Apostolopoulos N, Orlicky DJ, Schey K, Thompson DC, Vasiliou V. Impaired GSH biosynthesis disrupts eye development, lens morphogenesis and PAX6 function. Ocul Surf 2021; 22:190-203. [PMID: 34425299 DOI: 10.1016/j.jtos.2021.08.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/29/2021] [Accepted: 08/16/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE The purpose of this study was to elucidate the role and molecular consequences of impaired glutathione (GSH) biosynthesis on eye development. METHODS GSH biosynthesis was impaired in surface ectoderm-derived ocular tissues by crossing Gclcf/f mice with hemizygous Le-Cre transgenic mice to produce Gclcf/f/Le-CreTg/- (KO) mice. Control mice included Gclcf/fand Gclcwt/wt/Le-CreTg/- mice (CRE). Eyes from all mice (at various stages of eye development) were subjected to histological, immunohistochemical, Western blot, RT-qPCR, RNA-seq, and subsequent Gene Ontology, Ingenuity Pathway Analysis and TRANSFAC analyses. PAX6 transactivation activity was studied using a luciferase reporter assay in HEK293T cells depleted of GSH using buthionine sulfoximine (BSO). RESULTS Deletion of Gclc diminished GSH levels, increased reactive oxygen species (ROS), and caused an overt microphthalmia phenotype characterized by malformation of the cornea, iris, lens, and retina that is distinct from and much more profound than the one observed in CRE mice. In addition, only the lenses of KO mice displayed reduced crystallin (α, β), PITX3 and Foxe3 expression. RNA-seq analyses at postnatal day 1 revealed 1552 differentially expressed genes (DEGs) in the lenses of KO mice relative to those from Gclcf/f mice, with Crystallin and lens fiber cell identity genes being downregulated while lens epithelial cell identity and immune response genes were upregulated. Bioinformatic analysis of the DEGs implicated PAX6 as a key upstream regulator. PAX6 transactivation activity was impaired in BSO-treated HEK293T cells. CONCLUSIONS These data suggest that impaired ocular GSH biosynthesis may disrupt eye development and PAX6 function.
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Affiliation(s)
- Brian Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Emily A Davidson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Rolando Garcia-Milian
- Bioinformatics Support Program, Cushing/Whitney Medical Library, Yale School of Medicine, New Haven, CT, USA
| | - Jaya Prakash Golla
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA; Department of Medicine, Yale University School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | | | - David J Orlicky
- Department of Pathology, Anschutz School of Medicine, University of Colorado, Aurora, CO, USA
| | - Kevin Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - David C Thompson
- Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA.
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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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20
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Cole JD, Rodriguez C, Norat P, Gao J, Provencio I, Netland PA, Liu X. Neural damage and neuroprotection with glaucoma development in aniridia. CURRENT NEUROBIOLOGY 2021; 12:14-19. [PMID: 38125639 PMCID: PMC10732493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Affiliation(s)
- James D Cole
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | - Carlos Rodriguez
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Pedro Norat
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Jingyi Gao
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
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21
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Formulation and Stability of Ataluren Eye Drop Oily Solution for Aniridia. Pharmaceutics 2020; 13:pharmaceutics13010007. [PMID: 33375041 PMCID: PMC7822034 DOI: 10.3390/pharmaceutics13010007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/17/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Congenital aniridia is a rare and severe panocular disease characterized by a complete or partial iris defect clinically detectable at birth. The most common form of aniridia occurring in around 90% of cases is caused by PAX6 haploinsufficiency. The phenotype includes ptosis, nystagmus, corneal limbal insufficiency, glaucoma, cataract, optic nerve, and foveal hypoplasia. Ataluren eye drops aim to restore ocular surface PAX6 haploinsufficiency in aniridia-related keratopathy (ARK). However, there are currently no available forms of the ophthalmic solution. The objective of this study was to assess the physicochemical and microbiological stability of ataluren 1% eye drop in preservative-free low-density polyethylene (LDPE) bottle with an innovative insert that maintains sterility after opening. Because ataluren is a strongly lipophilic compound, the formulation is complex and involves a strategy based on co-solvents in an aqueous phase or an oily formulation capable of totally dissolving the active ingredient. The visual aspect, ataluren quantification by a stability-indicating chromatographic method, and microbiological sterility were analyzed. The oily formulation in castor oil and DMSO (10%) better protects ataluren hydrolysis and oxidative degradation and permits its complete solubilization. Throughout the 60 days period, the oily solution in the LDPE bottle remained clear without any precipitation or color modification, and no drug loss and no microbial development were detected. The demonstrated physical and microbiological stability of ataluren 1% eye drop formulation at 22–25 °C might facilitate clinical research in aniridia.
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Rabiee B, Anwar KN, Shen X, Putra I, Liu M, Jung R, Afsharkhamseh N, Rosenblatt MI, Fishman GA, Liu X, Ghassemi M, Djalilian AR. Gene dosage manipulation alleviates manifestations of hereditary PAX6 haploinsufficiency in mice. Sci Transl Med 2020; 12:eaaz4894. [PMID: 33298563 DOI: 10.1126/scitranslmed.aaz4894] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 04/16/2020] [Accepted: 09/04/2020] [Indexed: 12/15/2022]
Abstract
In autosomal dominant conditions with haploinsufficiency, a single functional allele cannot maintain sufficient dosage for normal function. We hypothesized that pharmacologic induction of the wild-type allele could lead to gene dosage compensation and mitigation of the disease manifestations. The paired box 6 (PAX6) gene is crucial in tissue development and maintenance particularly in eye, brain, and pancreas. Aniridia is a panocular condition with impaired eye development and limited vision due to PAX6 haploinsufficiency. To test our hypothesis, we performed a chemical screen and found mitogen-activated protein kinase kinase (MEK) inhibitors to induce PAX6 expression in normal and mutant corneal cells. Treatment of newborn Pax6-deficient mice (Pax6Sey-Neu/+ ) with topical or systemic MEK inhibitor PD0325901 led to increased corneal PAX6 expression, improved corneal morphology, reduced corneal opacity, and enhanced ocular function. These results suggest that induction of the wild-type allele by drug repurposing is a potential therapeutic strategy for haploinsufficiencies, which is not limited to specific mutations.
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Affiliation(s)
- Behnam Rabiee
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Khandaker N Anwar
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xiang Shen
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Ilham Putra
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Mingna Liu
- Departments of Biology and Psychology, University of Virginia, Charlottesville, VA 22903, USA
| | - Rebecca Jung
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Neda Afsharkhamseh
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Mark I Rosenblatt
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
- Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, IL 60608, USA
| | - Xiaorong Liu
- Departments of Biology and Psychology, University of Virginia, Charlottesville, VA 22903, USA
| | - Mahmood Ghassemi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Ali R Djalilian
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA.
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23
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Morphometric analysis of the lens in human aniridia and mouse Small eye. Exp Eye Res 2020; 203:108371. [PMID: 33248069 DOI: 10.1016/j.exer.2020.108371] [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: 08/03/2020] [Revised: 11/17/2020] [Accepted: 11/22/2020] [Indexed: 12/16/2022]
Abstract
Congenital aniridia is caused by heterozygous mutations in the PAX6 gene. In this disease, congenital iris and foveal hypoplasia is associated with juvenile onset cataract, glaucoma, and corneal keratopathy. In rodents, Pax6 mutations result in a congenital reduction in ocular size that is not typically described in human aniridia. Here, the ocular morphometry of aniridia patients is compared with the lens phenotype of Pax6+/tm1/Pgr mice to reveal whether there are species differences in Pax6 regulation of lens development and homeostasis. Ultrasound biometry (UBM) revealed that eleven percent of aniridia patients exhibited mild microphthalmia while the anterior chamber depth of aniridic eyes was significantly reduced from 6 months of age onward. Although aniridic lens thickness was normal from birth, it was significantly decreased in aniridic lenses older than 30. Notably, 86% of aniridic lenses exhibited cataractous changes in this cohort. In addition, a significant proportion of aniridia patients develop lens subluxation as they age associated with reduced lens diameter as measured by anterior segment optical coherence tomography (AS-OCT). Analysis of young adult Pax6+/tm1/Pgr mouse lenses by micro-computed tomography (microCT), bright field and dark field imaging revealed that they are reduced in size but did not exhibit overt cataracts at this age. Overall, this study reveals that congenital microphthalmia as assessed by axial length, or microphakia, as assessed by lens thickness, are not typical in human aniridia, although these are primary manifestations of Pax6 mutations in mice, suggesting that PAX6 regulates some aspects of lens development differently between these species.
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Nonsense Suppression Therapy: New Hypothesis for the Treatment of Inherited Bone Marrow Failure Syndromes. Int J Mol Sci 2020; 21:ijms21134672. [PMID: 32630050 PMCID: PMC7369780 DOI: 10.3390/ijms21134672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 12/13/2022] Open
Abstract
Inherited bone marrow failure syndromes (IBMFS) are a group of cancer-prone genetic diseases characterized by hypocellular bone marrow with impairment in one or more hematopoietic lineages. The pathogenesis of IBMFS involves mutations in several genes which encode for proteins involved in DNA repair, telomere biology and ribosome biogenesis. The classical IBMFS include Shwachman–Diamond syndrome (SDS), Diamond–Blackfan anemia (DBA), Fanconi anemia (FA), dyskeratosis congenita (DC), and severe congenital neutropenia (SCN). IBMFS are associated with high risk of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumors. Unfortunately, no specific pharmacological therapies have been highly effective for IBMFS. Hematopoietic stem cell transplantation provides a cure for aplastic or myeloid neoplastic complications. However, it does not affect the risk of solid tumors. Since approximately 28% of FA, 24% of SCN, 21% of DBA, 20% of SDS, and 17% of DC patients harbor nonsense mutations in the respective IBMFS-related genes, we discuss the use of the nonsense suppression therapy in these diseases. We recently described the beneficial effect of ataluren, a nonsense suppressor drug, in SDS bone marrow hematopoietic cells ex vivo. A similar approach could be therefore designed for treating other IBMFS. In this review we explain in detail the new generation of nonsense suppressor molecules and their mechanistic roles. Furthermore, we will discuss strengths and limitations of these molecules which are emerging from preclinical and clinical studies. Finally we discuss the state-of-the-art of preclinical and clinical therapeutic studies carried out for IBMFS.
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25
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Wang X, Shan X, Gregory-Evans K, Gregory-Evans CY. RNA-based therapies in animal models of Leber congenital amaurosis causing blindness. PRECISION CLINICAL MEDICINE 2020; 3:113-126. [PMID: 35692607 PMCID: PMC8985810 DOI: 10.1093/pcmedi/pbaa009] [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: 01/13/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 11/14/2022] Open
Abstract
Abstract
Leber congenital amaurosis (LCA) is a severe, genetically heterogeneous recessive eye disease in which ~ 35% of gene mutations are in-frame nonsense mutations coding for loss-of-function premature termination codons (PTCs) in mRNA. Nonsense suppression therapy allows read-through of PTCs leading to production of full-length protein. A limitation of nonsense suppression is that nonsense-mediated decay (NMD) degrades PTC-containing RNA transcripts. The purpose of this study was to determine whether inhibition of NMD could improve nonsense suppression efficacy in vivo. Using a high-throughput approach in the recessive cep290 zebrafish model of LCA (cep290;Q1223X), we first tested the NMD inhibitor Amlexanox in combination with the nonsense suppression drug Ataluren. We observed reduced retinal cell death and improved visual function. With these positive data, we next investigated whether this strategy was also applicable across species in two mammalian models: Rd12 (rpe65;R44X) and Rd3 (rd3;R107X) mouse models of LCA. In the Rd12 model, cell death was reduced, RPE65 protein was produced, and in vivo visual function testing was improved. We establish for the first time that the mechanism of action of Amlexanox in Rd12 retina was through reduced UPF1 phosphorylation. In the Rd3 model, however, no beneficial effect was observed with Ataluren alone or in combination with Amlexanox. This variation in response establishes that some forms of nonsense mutation LCA can be targeted by RNA therapies, but that this needs to be verified for each genotype. The implementation of precision medicine by identifying better responders to specific drugs is essential for development of validated retinal therapies.
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Affiliation(s)
- Xia Wang
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Xianghong Shan
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
| | - Cheryl Y Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver BC V5Z 3N9, Canada
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26
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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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27
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Mirjalili Mohanna SZ, Hickmott JW, Lam SL, Chiu NY, Lengyell TC, Tam BM, Moritz OL, Simpson EM. Germline CRISPR/Cas9-Mediated Gene Editing Prevents Vision Loss in a Novel Mouse Model of Aniridia. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 17:478-490. [PMID: 32258211 PMCID: PMC7114625 DOI: 10.1016/j.omtm.2020.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/09/2020] [Indexed: 12/18/2022]
Abstract
Aniridia is a rare eye disorder, which is caused by mutations in the paired box 6 (PAX6) gene and results in vision loss due to the lack of a long-term vision-saving therapy. One potential approach to treating aniridia is targeted CRISPR-based genome editing. To enable the Pax6 small eye (Sey) mouse model of aniridia, which carries the same mutation found in patients, for preclinical testing of CRISPR-based therapeutic approaches, we endogenously tagged the Sey allele, allowing for the differential detection of protein from each allele. We optimized a correction strategy in vitro then tested it in vivo in the germline of our new mouse to validate the causality of the Sey mutation. The genomic manipulations were analyzed by PCR, as well as by Sanger and next-generation sequencing. The mice were studied by slit lamp imaging, immunohistochemistry, and western blot analyses. We successfully achieved both in vitro and in vivo germline correction of the Sey mutation, with the former resulting in an average 34.8% ± 4.6% SD correction, and the latter in restoration of 3xFLAG-tagged PAX6 expression and normal eyes. Hence, in this study we have created a novel mouse model for aniridia, demonstrated that germline correction of the Sey mutation alone rescues the mutant phenotype, and developed an allele-distinguishing CRISPR-based strategy for aniridia.
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Affiliation(s)
- Seyedeh Zeinab Mirjalili Mohanna
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada.,Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
| | - Jack W Hickmott
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada.,Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
| | - Siu Ling Lam
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Nina Y Chiu
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada.,Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
| | - Tess C Lengyell
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Beatrice M Tam
- Department of Ophthalmology and Visual Sciences and Centre for Macular Research, The University of British Columbia, Vancouver, BC, Canada
| | - Orson L Moritz
- Department of Ophthalmology and Visual Sciences and Centre for Macular Research, The University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at British Columbia Children's Hospital, The University of British Columbia, Vancouver, BC V5Z 4H4, Canada.,Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
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28
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Liu X, Zhang Y, Zhang B, Gao H, Qiu C. Nonsense suppression induced readthrough of a novel PAX6 mutation in patient-derived cells of congenital aniridia. Mol Genet Genomic Med 2020; 8:e1198. [PMID: 32125788 PMCID: PMC7216799 DOI: 10.1002/mgg3.1198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 12/11/2022] Open
Abstract
Background Congenital aniridia is a severe ocular abnormality characterized by incomplete formation of the iris and many other ocular complications. Most cases are caused by the paired box 6 (PAX6) gene mutations generating premature termination codons (PTCs). Methods Ophthalmic examination was performed on a Chinese pedigree with congenital aniridia. The mutation was identified by targeted next‐generation sequencing. Nonsense suppression therapy was applied on patient‐derived lymphocytes. The PAX6 expression was assayed by real‐time polymerase chain reaction and Western blot. Results Complete aniridia was complicated with horizontal nystagmus, contract, foveal hypoplasia, and microphthalmia. A novel heterozygous c.702_703delinsAT (p.Tyr234*) mutation was found in exon 9 of PAX6, generating a PTC at the homeodomain. There were about 50% reductions of both full‐length PAX6 protein and PAX6 mRNA in patient‐derived lymphocytes, indicating haploinsufficiency due to nonsense‐mediated mRNA decay. Ataluren (PTC124) and geneticin (G418) could induce about 30%–40% translational readthrough. Nonsense suppression therapy restored PAX6 protein to about 65%–70% of unaffected family controls. Conclusion Our data expanded the genetic and phenotypic variations of congenital aniridia, and showed the therapeutic effect of nonsense suppression on this disease using patient‐derived cells.
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Affiliation(s)
- Xiaoliang Liu
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yuanyuan Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Bijun Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Haiming Gao
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Chuang Qiu
- Department of Orthopaedics, Shengjing Hospital of China Medical University, Shenyang, China
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29
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Lima Cunha D, Arno G, Corton M, Moosajee M. The Spectrum of PAX6 Mutations and Genotype-Phenotype Correlations in the Eye. Genes (Basel) 2019; 10:genes10121050. [PMID: 31861090 PMCID: PMC6947179 DOI: 10.3390/genes10121050] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
The transcription factor PAX6 is essential in ocular development in vertebrates, being considered the master regulator of the eye. During eye development, it is essential for the correct patterning and formation of the multi-layered optic cup and it is involved in the developing lens and corneal epithelium. In adulthood, it is mostly expressed in cornea, iris, and lens. PAX6 is a dosage-sensitive gene and it is highly regulated by several elements located upstream, downstream, and within the gene. There are more than 500 different mutations described to affect PAX6 and its regulatory regions, the majority of which lead to PAX6 haploinsufficiency, causing several ocular and systemic abnormalities. Aniridia is an autosomal dominant disorder that is marked by the complete or partial absence of the iris, foveal hypoplasia, and nystagmus, and is caused by heterozygous PAX6 mutations. Other ocular abnormalities have also been associated with PAX6 changes, and genotype-phenotype correlations are emerging. This review will cover recent advancements in PAX6 regulation, particularly the role of several enhancers that are known to regulate PAX6 during eye development and disease. We will also present an updated overview of the mutation spectrum, where an increasing number of mutations in the non-coding regions have been reported. Novel genotype-phenotype correlations will also be discussed.
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Affiliation(s)
| | - Gavin Arno
- Institute of Ophthalmology, UCL, 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
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital—Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Mariya Moosajee
- Institute of Ophthalmology, UCL, 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
- Correspondence:
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30
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Harding P, Moosajee M. The Molecular Basis of Human Anophthalmia and Microphthalmia. J Dev Biol 2019; 7:jdb7030016. [PMID: 31416264 PMCID: PMC6787759 DOI: 10.3390/jdb7030016] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 12/16/2022] Open
Abstract
Human eye development is coordinated through an extensive network of genetic signalling pathways. Disruption of key regulatory genes in the early stages of eye development can result in aborted eye formation, resulting in an absent eye (anophthalmia) or a small underdeveloped eye (microphthalmia) phenotype. Anophthalmia and microphthalmia (AM) are part of the same clinical spectrum and have high genetic heterogeneity, with >90 identified associated genes. By understanding the roles of these genes in development, including their temporal expression, the phenotypic variation associated with AM can be better understood, improving diagnosis and management. This review describes the genetic and structural basis of eye development, focusing on the function of key genes known to be associated with AM. In addition, we highlight some promising avenues of research involving multiomic approaches and disease modelling with induced pluripotent stem cell (iPSC) technology, which will aid in developing novel therapies.
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Affiliation(s)
| | - 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.
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31
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Johnson AF, Nguyen HT, Veitia RA. Causes and effects of haploinsufficiency. Biol Rev Camb Philos Soc 2019; 94:1774-1785. [DOI: 10.1111/brv.12527] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/08/2019] [Accepted: 05/10/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Adam F. Johnson
- Institute of Research and DevelopmentDuy Tan University Da Nang, 550000 Vietnam
| | - Ha T. Nguyen
- Institute of Research and DevelopmentDuy Tan University Da Nang, 550000 Vietnam
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32
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Di Iorio E, Barbaro V, Alvisi G, Trevisan M, Ferrari S, Masi G, Nespeca P, Ghassabian H, Ponzin D, Palù G. New Frontiers of Corneal Gene Therapy. Hum Gene Ther 2019; 30:923-945. [PMID: 31020856 DOI: 10.1089/hum.2019.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Corneal diseases are among the most prevalent causes of blindness worldwide. The transparency and clarity of the cornea are guaranteed by a delicate physiological, anatomic, and functional balance. For this reason, all the disorders, including those of genetic origin, that compromise this state of harmony can lead to opacity and eventually vision loss. Many corneal disorders have a genetic etiology, and some are associated with rather rare and complex syndromes. Conventional treatments, such as corneal transplantation, are often ineffective, and to date, many of these disorders are still incurable. Gene therapy carries the promise of being a potential cure for many of these diseases, with solutions and strategies that did not seem possible until a few years ago. With its potential to treat genetic disease by means of deletion, replacement, or editing of a defective gene, the challenge can also be extended to corneal disorders in order to achieve long-term, if not definitive, relief. The aim of this paper is to review the state of the art of the different gene therapy approaches as potential treatments for corneal diseases and the future perspectives for the development of personalized gene-based medicine.
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Affiliation(s)
- Enzo Di Iorio
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Vanessa Barbaro
- 2Fondazione Banca Degli Occhi Del Veneto Onlus, Zelarino, Venezia, Italy
| | - Gualtiero Alvisi
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Marta Trevisan
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Stefano Ferrari
- 2Fondazione Banca Degli Occhi Del Veneto Onlus, Zelarino, Venezia, Italy
| | - Giulia Masi
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Patrizia Nespeca
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Hanieh Ghassabian
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Diego Ponzin
- 2Fondazione Banca Degli Occhi Del Veneto Onlus, Zelarino, Venezia, Italy
| | - Giorgio Palù
- 1Department of Molecular Medicine, University of Padova, Padova, Italy
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Ohuchi H, Sato K, Habuta M, Fujita H, Bando T. Congenital eye anomalies: More mosaic than thought? Congenit Anom (Kyoto) 2019; 59:56-73. [PMID: 30039880 DOI: 10.1111/cga.12304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022]
Abstract
The eye is a sensory organ that primarily captures light and provides the sense of sight, as well as delivering non-visual light information involving biological rhythms and neurophysiological activities to the brain. Since the early 1990s, rapid advances in molecular biology have enabled the identification of developmental genes, genes responsible for human congenital diseases, and relevant genes of mutant animals with various anomalies. In this review, we first look at the development of the eye, and we highlight seminal reports regarding archetypal gene defects underlying three developmental ocular disorders in humans: (1) holoprosencephaly (HPE), with cyclopia being exhibited in the most severe cases; (2) microphthalmia, anophthalmia, and coloboma (MAC) phenotypes; and (3) anterior segment dysgenesis (ASDG), known as Peters anomaly and its related disorders. The recently developed methods, such as next-generation sequencing and genome editing techniques, have aided the discovery of gene mutations in congenital eye diseases and gene functions in normal eye development. Finally, we discuss Pax6-genome edited mosaic eyes and propose that somatic mosaicism in developmental gene mutations should be considered a causal factor for variable phenotypes, sporadic cases, and de novo mutations in human developmental disorders.
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Affiliation(s)
- Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Keita Sato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Munenori Habuta
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hirofumi Fujita
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tetsuya Bando
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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Krall M, Htun S, Slavotinek A. Use of PTC124 for nonsense suppression therapy targeting BMP4 nonsense variants in vitro and the bmp4st72 allele in zebrafish. PLoS One 2019; 14:e0212121. [PMID: 31017898 PMCID: PMC6481805 DOI: 10.1371/journal.pone.0212121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 04/07/2019] [Indexed: 12/04/2022] Open
Abstract
Nonsense suppression therapy (NST) utilizes compounds such as PTC124 (Ataluren) to induce translational read-through of stop variants by promoting the insertion of near cognate, aminoacyl tRNAs that yield functional proteins. We used NST with PTC124 to determine if we could successfully rescue nonsense variants in human Bone Morphogenetic Protein 4 (BMP4) in vitro and in a zebrafish bmp4 allele with a stop variant in vivo. We transfected 293T/17 cells with wildtype or mutant human BMP4 cDNA containing p.Arg198* and p.Glu213* and exposed cells to 0–20 μM PTC124. Treatment with 20 μM PTC124 produced a small, non-significant increase in BMP4 when targeting the p.Arg198* allele, but not the p.Glu213* allele, as measured with an In-cell ELISA assay. We then examined the ability of PTC124 to rescue the ventral tail fin defects associated with homozygosity for the p.Glu209* allele of bmp4 (bmp4st72/st72) in Danio rerio. We in-crossed bmp4st72/+ heterozygous fish and found a statistically significant increase in homozygous larvae without tail fin and ventroposterior defects, consistent with phenotypic rescue, after treatment of dechorionated larvae with 0.5 μM PTC124. We conclude that treatment with PTC124 can rescue bmp4 nonsense variants, but that the degree of rescue may depend on sequence specific factors and the amount of RNA transcript available for rescue. Our work also confirms that zebrafish show promise as a useful animal model for assessing the efficacy of PTC124 treatment on nonsense variants.
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Affiliation(s)
- Max Krall
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Stephanie Htun
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
| | - Anne Slavotinek
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, United States of America
- * E-mail:
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35
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Prospects and modalities for the treatment of genetic ocular anomalies. Hum Genet 2019; 138:1019-1026. [DOI: 10.1007/s00439-018-01968-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 12/24/2018] [Indexed: 12/13/2022]
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36
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Epistasis between Pax6 Sey and genetic background reinforces the value of defined hybrid mouse models for therapeutic trials. Gene Ther 2018; 25:524-537. [PMID: 30258099 PMCID: PMC6335240 DOI: 10.1038/s41434-018-0043-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/02/2018] [Accepted: 09/05/2018] [Indexed: 12/21/2022]
Abstract
The small eye (Sey) mouse is a model of PAX6-aniridia syndrome (aniridia). Aniridia, a congenital ocular disorder caused by heterozygous loss-of-function mutations in PAX6, needs new vision saving therapies. However, high phenotypic variability in Sey mice makes development of such therapies challenging. We hypothesize that genetic background is a major source of undesirable variability in Sey mice. Here we performed a systematic quantitative examination of anatomical, histological, and molecular phenotypes on the inbred C57BL/6J, hybrid B6129F1, and inbred 129S1/SvImJ backgrounds. The Sey allele significantly reduced eye weight, corneal thickness, PAX6 mRNA and protein levels, and elevated blood glucose levels. Surprisingly, Pax6Sey/Sey brains had significantly elevated Pax6 transcripts compared to Pax6+/+ embryos. Genetic background significantly influenced 12/24 measurements, with inbred strains introducing severe ocular and blood sugar phenotypes not observed in hybrid mice. Additionally, significant interactions (epistasis) between Pax6 genotype and genetic background were detected in measurements of eye weight, cornea epithelial thickness and cell count, retinal mRNA levels, and blood glucose levels. The number of epistatic interactions was reduced in hybrid mice. In conclusion, severe phenotypes in the unnatural inbred strains reinforce the value of more naturalistic F1 hybrid mice for the development of therapies for aniridia and other disorders.
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Yongblah K, Alford SC, Ryan BC, Chow RL, Howard PL. Protecting Pax6 3' UTR from MicroRNA-7 Partially Restores PAX6 in Islets from an Aniridia Mouse Model. MOLECULAR THERAPY. NUCLEIC ACIDS 2018; 13:144-153. [PMID: 30290306 PMCID: PMC6171161 DOI: 10.1016/j.omtn.2018.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 08/16/2018] [Accepted: 08/27/2018] [Indexed: 02/06/2023]
Abstract
Aniridia is a rare congenital syndrome that is associated with reduced visual acuity and progressive loss of vision. Aniridia patients may also develop systemic health issues associated with defects in the pancreas, digestive, and central nervous systems. The spectrum of symptoms associated with aniridia is due to haploinsufficiency of the paired box 6 gene (PAX6) and its role in the development and maintenance of the affected tissues. Here, we isolated pancreatic islets from mice heterozygous for Pax6 to test whether a Pax6-specific miRNA suppression (target protector) strategy can restore PAX6 protein levels. We show that miR-7 and miR-375 target specific sites within the Pax6 3' UTR in a mouse pancreatic β-insulinoma cell line. Tough decoys (Tuds) against miR-7 and miR-375 increase expression of a mouse Pax6 3' UTR luciferase reporter and increase PAX6 protein levels in these cells. Finally, we demonstrate that the shielding of the miR-7 binding site with a target protector restores PAX6 protein levels in the Pax6 heterozygous islets. The data presented here represent a proof of concept for RNA-based therapy for the progressive defects associated with aniridia and suggest the target protector approach may be a useful therapeutic strategy for other haploinsufficiency diseases.
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Affiliation(s)
- Kevin Yongblah
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada
| | - Spencer C Alford
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada
| | - Bridget C Ryan
- Department of Biology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Perry L Howard
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700 STN CSC, Victoria, BC V8W2Y2, Canada.
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Roux LN, Petit I, Domart R, Concordet JP, Qu J, Zhou H, Joliot A, Ferrigno O, Aberdam D. Modeling of Aniridia-Related Keratopathy by CRISPR/Cas9 Genome Editing of Human Limbal Epithelial Cells and Rescue by Recombinant PAX6 Protein. Stem Cells 2018; 36:1421-1429. [PMID: 29808941 DOI: 10.1002/stem.2858] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/08/2018] [Accepted: 05/14/2018] [Indexed: 12/24/2022]
Abstract
Heterozygous PAX6 gene mutations leading to haploinsufficiency are the main cause of congenital aniridia, a rare and progressive panocular disease characterized by reduced visual acuity. Up to 90% of patients suffer from aniridia-related keratopathy (ARK), caused by a combination of factors including limbal epithelial stem cell (LSC) deficiency, impaired healing response and abnormal differentiation of the corneal epithelium. It usually begins in the first decade of life, resulting in recurrent corneal erosions, sub-epithelial fibrosis, and corneal opacification. Unfortunately, there are currently no efficient treatments available for these patients and no in vitro model for this pathology. We used CRISPR/Cas9 technology to introduce into the PAX6 gene of LSCs a heterozygous nonsense mutation found in ARK patients. Nine clones carrying a p.E109X mutation on one allele were obtained with no off-target mutations. Compared with the parental LSCs, heterozygous mutant LSCs displayed reduced expression of PAX6 and marked slow-down of cell proliferation, migration and detachment. Moreover, addition to the culture medium of recombinant PAX6 protein fused to a cell penetrating peptide was able to activate the endogenous PAX6 gene and to rescue phenotypic defects of mutant LSCs, suggesting that administration of such recombinant PAX6 protein could be a promising therapeutic approach for aniridia-related keratopathy. More generally, our results demonstrate that introduction of disease mutations into LSCs by CRISPR/Cas9 genome editing allows the creation of relevant cellular models of ocular disease that should greatly facilitate screening of novel therapeutic approaches. Stem Cells 2018;36:1421-1429.
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Affiliation(s)
- Lauriane N Roux
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Isabelle Petit
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Romain Domart
- INSERM U1154, CNRS UMR 7196, Museum National d'Histoire Naturelle, Paris, France
| | - Jean-Paul Concordet
- INSERM U1154, CNRS UMR 7196, Museum National d'Histoire Naturelle, Paris, France
| | - Jieqiong Qu
- Department of Human Developmental biology, Radboud University, Nijmegen, The Netherlands.,Faculty of Sciences, Department of Human Genetics, Radboud University Nijmegen, The Netherlands
| | - Huiqing Zhou
- Department of Human Developmental biology, Radboud University, Nijmegen, The Netherlands.,Faculty of Sciences, Department of Human Genetics, Radboud University Nijmegen, The Netherlands
| | - Alain Joliot
- Collège de France CNRS/UMR 7241 - INSERM U1050, Paris, France
| | | | - Daniel Aberdam
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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Wawrocka A, Krawczynski MR. The genetics of aniridia - simple things become complicated. J Appl Genet 2018; 59:151-159. [PMID: 29460221 PMCID: PMC5895662 DOI: 10.1007/s13353-017-0426-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/21/2017] [Accepted: 12/21/2017] [Indexed: 12/26/2022]
Abstract
Aniridia is a rare, panocular disorder characterized by a variable degree of hypoplasia or the absence of iris tissue associated with additional ocular abnormalities. It is inherited in an autosomal dominant manner, with high penetrance and variable expression even within the same family. In most cases the disease is caused by haploinsufficiency truncating mutations in the PAX6 gene; however, in up to 30% of aniridia patients, disease results from chromosomal rearrangements at the 11p13 region. The aim of this review is to present the clinical and genetic aspects of the disease. Furthermore, we present a molecular diagnostic strategy in the aniridia patients. Recent improvement in the genetic diagnostic approach will precisely diagnosis aniridia patients, which is essential especially for children with aniridia in order to determine the risk of developing a Wilms tumor or neurodevelopmental disorder. Finally, based on the previous studies we describe the current knowledge and latest research findings in the topic of pathogenesis of aniridia and possible future treatment.
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Affiliation(s)
- Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8, 60-806, Poznan, Poland.
| | - Maciej R Krawczynski
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8, 60-806, Poznan, Poland
- Centers for Medical Genetics GENESIS, Poznan, Poland
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