1
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Premchandar A, Ming R, Baiad A, Da Fonte DF, Xu H, Faubert D, Veit G, Lukacs GL. Readthrough-induced misincorporated amino acid ratios guide mutant-specific therapeutic approaches for two CFTR nonsense mutations. Front Pharmacol 2024; 15:1389586. [PMID: 38725656 PMCID: PMC11079177 DOI: 10.3389/fphar.2024.1389586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 05/12/2024] Open
Abstract
Cystic fibrosis (CF) is a monogenic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Premature termination codons (PTCs) represent ∼9% of CF mutations that typically cause severe expression defects of the CFTR anion channel. Despite the prevalence of PTCs as the underlying cause of genetic diseases, understanding the therapeutic susceptibilities of their molecular defects, both at the transcript and protein levels remains partially elucidated. Given that the molecular pathologies depend on the PTC positions in CF, multiple pharmacological interventions are required to suppress the accelerated nonsense-mediated mRNA decay (NMD), to correct the CFTR conformational defect caused by misincorporated amino acids, and to enhance the inefficient stop codon readthrough. The G418-induced readthrough outcome was previously investigated only in reporter models that mimic the impact of the local sequence context on PTC mutations in CFTR. To identify the misincorporated amino acids and their ratios for PTCs in the context of full-length CFTR readthrough, we developed an affinity purification (AP)-tandem mass spectrometry (AP-MS/MS) pipeline. We confirmed the incorporation of Cys, Arg, and Trp residues at the UGA stop codons of G542X, R1162X, and S1196X in CFTR. Notably, we observed that the Cys and Arg incorporation was favored over that of Trp into these CFTR PTCs, suggesting that the transcript sequence beyond the proximity of PTCs and/or other factors can impact the amino acid incorporation and full-length CFTR functional expression. Additionally, establishing the misincorporated amino acid ratios in the readthrough CFTR PTCs aided in maximizing the functional rescue efficiency of PTCs by optimizing CFTR modulator combinations. Collectively, our findings contribute to the understanding of molecular defects underlying various CFTR nonsense mutations and provide a foundation to refine mutation-dependent therapeutic strategies for various CF-causing nonsense mutations.
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Affiliation(s)
| | - Ruiji Ming
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Abed Baiad
- Department of Physiology, McGill University, Montréal, QC, Canada
| | | | - Haijin Xu
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Denis Faubert
- IRCM Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
| | - Guido Veit
- Department of Physiology, McGill University, Montréal, QC, Canada
| | - Gergely L. Lukacs
- Department of Physiology, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
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2
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Marques-Mejias A, Bartha I, Ciaccio CE, Chinthrajah RS, Chan S, Hershey GKK, Hui-Beckman JW, Kost L, Lack G, Layhadi JA, Leung DYM, Marshall HF, Nadeau KC, Radulovic S, Rajcoomar R, Shamji MH, Sindher S, Brough HA. Skin as the target for allergy prevention and treatment. Ann Allergy Asthma Immunol 2024:S1081-1206(24)00001-2. [PMID: 38253125 DOI: 10.1016/j.anai.2023.12.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/27/2023] [Accepted: 12/26/2023] [Indexed: 01/24/2024]
Abstract
The fact that genetic and environmental factors could trigger disruption of the epithelial barrier and subsequently initiate a TH2 inflammatory cascade conversely proposes that protecting the same barrier and promoting adequate interactions with other organs, such as the gut, may be crucial for lowering the risk and preventing atopic diseases, particularly, food allergies. In this review, we provide an overview of structural characteristics that support the epithelial barrier hypothesis in patients with atopic dermatitis, including the most relevant filaggrin gene mutations, the recent discovery of the role of the transient receptor potential vanilloid 1, and the role involvement of the microbiome in healthy and damaged skin. We present experimental and human studies that support the mechanisms of allergen penetration, particularly the dual allergen exposure and the outside-in, inside-out, and outside-inside-outside hypotheses. We discuss classic skin-targeted therapies for food allergy prevention, including moisturizers, steroids, and topical calcineurin inhibitors, along with pioneering trials proposed to change their current use (Prevention of Allergy via Cutaneous Intervention and Stopping Eczema and ALlergy). We provide an overview of the novel therapies that enhance the skin barrier, such as probiotics and prebiotics topical application, read-through drugs, direct and indirect FLG replacement, and interleukin and janus kinases inhibitors. Last, we discuss the newer strategies for preventing and treating food allergies in the form of epicutaneous immunotherapy and the experimental use of single-dose of adeno-associated virus vector gene immunotherapy.
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Affiliation(s)
- Andreina Marques-Mejias
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom
| | - Irene Bartha
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom
| | - Christina E Ciaccio
- Department of Pediatrics, The University of Chicago, Chicago, Illinois; Department of Medicine, The University of Chicago, Chicago, Illinois
| | - R Sharon Chinthrajah
- Department of Medicine, and Sean N Parker Center for Allergy and Asthma Research, Stanford University, Palo Alto, California
| | - Susan Chan
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom; Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, United Kingdom
| | - Gurjit K Khurana Hershey
- Division of Asthma Research, Cincinnati Children's Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | | | - Laurie Kost
- Department of Medicine, and Sean N Parker Center for Allergy and Asthma Research, Stanford University, Palo Alto, California
| | - Gideon Lack
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom; Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, United Kingdom
| | - Janice A Layhadi
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts
| | - Donald Y M Leung
- Department of Pediatrics, National Jewish Health, Denver, Colorado
| | - Hannah F Marshall
- Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom
| | - Kari C Nadeau
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Suzana Radulovic
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom; Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, United Kingdom
| | - Reena Rajcoomar
- Department of Medicine, and Sean N Parker Center for Allergy and Asthma Research, Stanford University, Palo Alto, California
| | - Mohamed H Shamji
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Sayantani Sindher
- Department of Medicine, and Sean N Parker Center for Allergy and Asthma Research, Stanford University, Palo Alto, California
| | - Helen A Brough
- Department of Women and Children's Health (Paediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom; Children's Allergy Service, Evelina London, Guy's and St Thomas', NHS Foundation Trust, London, United Kingdom; Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, United Kingdom.
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3
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Torices L, Nunes-Xavier CE, Mingo J, Luna S, Erramuzpe A, Cortés JM, Pulido R. Induction of Translational Readthrough on Protein Tyrosine Phosphatases Targeted by Premature Termination Codon Mutations in Human Disease. Methods Mol Biol 2024; 2743:1-19. [PMID: 38147205 DOI: 10.1007/978-1-0716-3569-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Nonsense mutations generating premature termination codons (PTCs) in various genes are frequently associated with somatic cancer and hereditary human diseases since PTCs commonly generate truncated proteins with defective or altered function. Induced translational readthrough during protein biosynthesis facilitates the incorporation of an amino acid at the position of a PTC, allowing the synthesis of a complete protein. This may evade the pathological effect of the PTC mutation and provide new therapeutic opportunities. Several protein tyrosine phosphatases (PTPs) genes are targeted by PTC in human disease, the tumor suppressor PTEN being the more prominent paradigm. Here, using PTEN and laforin as examples, two PTPs from the dual-specificity phosphatase subfamily, we describe methodologies to analyze in silico the distribution and frequency of pathogenic PTC in PTP genes. We also summarize laboratory protocols and technical notes to study the induced translational readthrough reconstitution of the synthesis of PTP targeted by PTC in association with disease in cellular models.
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Affiliation(s)
- Leire Torices
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Caroline E Nunes-Xavier
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway
| | - Janire Mingo
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Sandra Luna
- Biobizkaia Health Research Institute, Barakaldo, Spain
| | - Asier Erramuzpe
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
| | - Jesús M Cortés
- Biobizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
- Cell Biology and Histology Department, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Rafael Pulido
- Biobizkaia Health Research Institute, Barakaldo, Spain.
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain.
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4
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Gurzeler LA, Link M, Ibig Y, Schmidt I, Galuba O, Schoenbett J, Gasser-Didierlaurant C, Parker CN, Mao X, Bitsch F, Schirle M, Couttet P, Sigoillot F, Ziegelmüller J, Uldry AC, Teodorowicz W, Schmiedeberg N, Mühlemann O, Reinhardt J. Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control. Cell Rep 2023; 42:113056. [PMID: 37651229 DOI: 10.1016/j.celrep.2023.113056] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/15/2023] [Accepted: 08/16/2023] [Indexed: 09/02/2023] Open
Abstract
Suppression of premature termination codons (PTCs) by translational readthrough is a promising strategy to treat a wide variety of severe genetic diseases caused by nonsense mutations. Here, we present two potent readthrough promoters-NVS1.1 and NVS2.1-that restore substantial levels of functional full-length CFTR and IDUA proteins in disease models for cystic fibrosis and Hurler syndrome, respectively. In contrast to other readthrough promoters that affect stop codon decoding, the NVS compounds stimulate PTC suppression by triggering rapid proteasomal degradation of the translation termination factor eRF1. Our results show that this occurs by trapping eRF1 in the terminating ribosome, causing ribosome stalls and subsequent ribosome collisions, and activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25.
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Affiliation(s)
- Lukas-Adrian Gurzeler
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Marion Link
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Yvonne Ibig
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Isabel Schmidt
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Olaf Galuba
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | | | - Xiaohong Mao
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Francis Bitsch
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Markus Schirle
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Philipp Couttet
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Jana Ziegelmüller
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Wojciech Teodorowicz
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
| | - Jürgen Reinhardt
- Novartis Institutes for BioMedical Research, Basel, Switzerland.
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5
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Daich Varela M, Georgiadis A, Michaelides M. Genetic treatment for autosomal dominant inherited retinal dystrophies: approaches, challenges and targeted genotypes. Br J Ophthalmol 2023; 107:1223-1230. [PMID: 36038193 DOI: 10.1136/bjo-2022-321903] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/01/2022] [Indexed: 11/04/2022]
Abstract
Inherited retinal diseases (IRDs) have been in the front line of gene therapy development for the last decade, providing a useful platform to test novel therapeutic approaches. More than 40 clinical trials have been completed or are ongoing, tackling autosomal recessive and X-linked conditions, mostly through adeno-associated viral vector delivery of a normal copy of the disease-causing gene. However, only recently has autosomal dominant (ad) disease been targeted, with the commencement of a trial for rhodopsin (RHO)-associated retinitis pigmentosa (RP), implementing antisense oligonucleotide (AON) therapy, with promising preliminary results (NCT04123626).Autosomal dominant RP represents 15%-25% of all RP, with RHO accounting for 20%-30% of these cases. Autosomal dominant macular and cone-rod dystrophies (MD/CORD) correspond to approximately 7.5% of all IRDs, and approximately 35% of all MD/CORD cases, with the main causative gene being BEST1 Autosomal dominant IRDs are not only less frequent than recessive, but also tend to be less severe and have later onset; for example, an individual with RHO-adRP would typically become severely visually impaired at an age 2-3 times older than in X-linked RPGR-RP.Gain-of-function and dominant negative aetiologies are frequently seen in the prevalent adRP genes RHO, RP1 and PRPF31 among others, which would not be effectively addressed by gene supplementation alone and need creative, novel approaches. Zinc fingers, RNA interference, AON, translational read-through therapy, and gene editing by clustered regularly interspaced short palindromic repeats/Cas are some of the strategies that are currently under investigation and will be discussed here.
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Affiliation(s)
- Malena Daich Varela
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | | | - Michel Michaelides
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
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6
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Wong KM, Wegener E, Baradaran-Heravi A, Huppke B, Gärtner J, Huppke P. Evaluation of Novel Enhancer Compounds in Gentamicin-Mediated Readthrough of Nonsense Mutations in Rett Syndrome. Int J Mol Sci 2023; 24:11665. [PMID: 37511424 PMCID: PMC10380790 DOI: 10.3390/ijms241411665] [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: 06/21/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Rett syndrome (RTT), a severe X-linked neurodevelopmental disorder, is primarily caused by mutations in the methyl CpG binding protein 2 gene (MECP2). Over 35% RTT patients carry nonsense mutation in MECP2, making it a suitable candidate disease for nonsense suppression therapy. In our previous study, gentamicin was found to induce readthrough of MECP2 nonsense mutations with modest efficiency. Given the recent discovery of readthrough enhancers, CDX compounds, we herein evaluated the potentiation effect of CDX5-1, CDX5-288, and CDX6-180 on gentamicin-mediated readthrough efficiency in transfected HeLa cell lines bearing the four most common MECP2 nonsense mutations. We showed that all three CDX compounds potentiated gentamicin-mediated readthrough and increased full-length MeCP2 protein levels in cells expressing the R168X, R255X, R270X, and R294X nonsense mutations. Among all three CDX compounds, CDX5-288 was the most potent enhancer and enabled the use of reduced doses of gentamicin, thus mitigating the toxicity. Furthermore, we successfully demonstrated the upregulation of full-length Mecp2 protein expression in fibroblasts derived from Mecp2R255X/Y mice through combinatorial treatment. Taken together, findings demonstrate the feasibility of this combinatorial approach to nonsense suppression therapy for a subset of RTT patients.
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Affiliation(s)
- Keit Men Wong
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
| | - Eike Wegener
- Department of Pediatrics and Adolescent Medicine, Division of Neuropediatrics, Pediatric Neurology University Medical Center Göttingen, Georg August University Göttingen, 37075 Göttingen, Germany
| | - Alireza Baradaran-Heravi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC V6T 1Z3, Canada
| | - Brenda Huppke
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, Division of Neuropediatrics, Pediatric Neurology University Medical Center Göttingen, Georg August University Göttingen, 37075 Göttingen, Germany
| | - Peter Huppke
- Department of Neuropediatrics, Jena University Hospital, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, 07747 Jena, Germany
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7
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Li S, Li J, Shi W, Nie Z, Zhang S, Ma F, Hu J, Chen J, Li P, Xie X. Pharmaceuticals Promoting Premature Termination Codon Readthrough: Progress in Development. Biomolecules 2023; 13:988. [PMID: 37371567 DOI: 10.3390/biom13060988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/27/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Around 11% of all known gene lesions causing human genetic diseases are nonsense mutations that introduce a premature stop codon (PTC) into the protein-coding gene sequence. Drug-induced PTC readthrough is a promising therapeutic strategy for treating hereditary diseases caused by nonsense mutations. To date, it has been found that more than 50 small-molecular compounds can promote PTC readthrough, known as translational readthrough-inducing drugs (TRIDs), and can be divided into two major categories: aminoglycosides and non-aminoglycosides. This review summarizes the pharmacodynamics and clinical application potential of the main TRIDs discovered so far, especially some newly discovered TRIDs in the past decade. The discovery of these TRIDs brings hope for treating nonsense mutations in various genetic diseases. Further research is still needed to deeply understand the mechanism of eukaryotic cell termination and drug-induced PTC readthrough so that patients can achieve the greatest benefit from the various TRID treatments.
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Affiliation(s)
- Shan Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Juan Li
- Central Laboratory, The First Hospital of Lanzhou University, Lanzhou 730000, China
- Gansu Key Laboratory of Genetic Study of Hematopathy, The First Hospital of Lanzhou University, Lanzhou 730000, China
| | - Wenjing Shi
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ziyan Nie
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Shasha Zhang
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Fengdie Ma
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jun Hu
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jianjun Chen
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Peiqiang Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaodong Xie
- School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China
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8
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Wagner RN, Wießner M, Friedrich A, Zandanell J, Breitenbach-Koller H, Bauer JW. Emerging Personalized Opportunities for Enhancing Translational Readthrough in Rare Genetic Diseases and Beyond. Int J Mol Sci 2023; 24:6101. [PMID: 37047074 PMCID: PMC10093890 DOI: 10.3390/ijms24076101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Nonsense mutations trigger premature translation termination and often give rise to prevalent and rare genetic diseases. Consequently, the pharmacological suppression of an unscheduled stop codon represents an attractive treatment option and is of high clinical relevance. At the molecular level, the ability of the ribosome to continue translation past a stop codon is designated stop codon readthrough (SCR). SCR of disease-causing premature termination codons (PTCs) is minimal but small molecule interventions, such as treatment with aminoglycoside antibiotics, can enhance its frequency. In this review, we summarize the current understanding of translation termination (both at PTCs and at cognate stop codons) and highlight recently discovered pathways that influence its fidelity. We describe the mechanisms involved in the recognition and readthrough of PTCs and report on SCR-inducing compounds currently explored in preclinical research and clinical trials. We conclude by reviewing the ongoing attempts of personalized nonsense suppression therapy in different disease contexts, including the genetic skin condition epidermolysis bullosa.
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Affiliation(s)
- Roland N. Wagner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Michael Wießner
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | - Andreas Friedrich
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
- Department of Biosciences, University of Salzburg, 5020 Salzburg, Austria
| | - Johanna Zandanell
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
| | | | - Johann W. Bauer
- Department of Dermatology and Allergology, University Hospital of the Paracelsus Medical University, 5020 Salzburg, Austria
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9
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Siddiqui A, Dundar H, Sharma J, Kaczmarczyk A, Echols J, Dai Y, Sun CR, Du M, Liu Z, Zhao R, Wood T, Sanders S, Rasmussen L, Bostwick JR, Augelli-Szafran C, Suto M, Rowe SM, Bedwell DM, Keeling KM. Triamterene Functions as an Effective Nonsense Suppression Agent for MPS I-H (Hurler Syndrome). Int J Mol Sci 2023; 24:4521. [PMID: 36901952 PMCID: PMC10003437 DOI: 10.3390/ijms24054521] [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: 02/03/2023] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
Mucopolysaccharidosis I-Hurler (MPS I-H) is caused by the loss of α-L-iduronidase, a lysosomal enzyme that degrades glycosaminoglycans. Current therapies cannot treat many MPS I-H manifestations. In this study, triamterene, an FDA-approved, antihypertensive diuretic, was found to suppress translation termination at a nonsense mutation associated with MPS I-H. Triamterene rescued enough α-L-iduronidase function to normalize glycosaminoglycan storage in cell and animal models. This new function of triamterene operates through premature termination codon (PTC) dependent mechanisms that are unaffected by epithelial sodium channel activity, the target of triamterene's diuretic function. Triamterene represents a potential non-invasive treatment for MPS I-H patients carrying a PTC.
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Affiliation(s)
- Amna Siddiqui
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Halil Dundar
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Next Generation Sequencing Transplant Diagnostics, Thermo-Fisher Scientific, West Hills, CA 91304, USA
| | - Jyoti Sharma
- Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Division of Infectious Diseases, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Aneta Kaczmarczyk
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- ARUP Laboratories, Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Josh Echols
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yanying Dai
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Chuanxi Richard Sun
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ming Du
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Zhong Liu
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Rui Zhao
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Tim Wood
- Greenwood Genetic Center, Greenwood, SC 29646, USA
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | | | | | | | - Mark Suto
- Southern Research, Birmingham, AL 35205, USA
| | - Steven M. Rowe
- Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - David M. Bedwell
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kim M. Keeling
- Department of Biochemistry & Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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10
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Epicutaneous Sensitization and Food Allergy: Preventive Strategies Targeting Skin Barrier Repair-Facts and Challenges. Nutrients 2023; 15:nu15051070. [PMID: 36904070 PMCID: PMC10005101 DOI: 10.3390/nu15051070] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/16/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023] Open
Abstract
Food allergy represents a growing public health and socio-economic problem with an increasing prevalence over the last two decades. Despite its substantial impact on the quality of life, current treatment options for food allergy are limited to strict allergen avoidance and emergency management, creating an urgent need for effective preventive strategies. Advances in the understanding of the food allergy pathogenesis allow to develop more precise approaches targeting specific pathophysiological pathways. Recently, the skin has become an important target for food allergy prevention strategies, as it has been hypothesized that allergen exposure through the impaired skin barrier might induce an immune response resulting in subsequent development of food allergy. This review aims to discuss current evidence supporting this complex interplay between the skin barrier dysfunction and food allergy by highlighting the crucial role of epicutaneous sensitization in the causality pathway leading to food allergen sensitization and progression to clinical food allergy. We also summarize recently studied prophylactic and therapeutic interventions targeting the skin barrier repair as an emerging food allergy prevention strategy and discuss current evidence controversies and future challenges. Further studies are needed before these promising strategies can be routinely implemented as prevention advice for the general population.
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11
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Schäfer J, Wenck N, Janik K, Linnert J, Stingl K, Kohl S, Nagel-Wolfrum K, Wolfrum U. The Usher syndrome 1C protein harmonin regulates canonical Wnt signaling. Front Cell Dev Biol 2023; 11:1130058. [PMID: 36846582 PMCID: PMC9944737 DOI: 10.3389/fcell.2023.1130058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Human Usher syndrome (USH) is the most common form of hereditary combined deaf-blindness. USH is a complex genetic disorder, and the pathomechanisms underlying the disease are far from being understood, especially in the eye and retina. The USH1C gene encodes the scaffold protein harmonin which organizes protein networks due to binary interactions with other proteins, such as all USH proteins. Interestingly, only the retina and inner ear show a disease-related phenotype, although USH1C/harmonin is almost ubiquitously expressed in the human body and upregulated in colorectal cancer. We show that harmonin binds to β-catenin, the key effector of the canonical Wnt (cWnt) signaling pathway. We also demonstrate the interaction of the scaffold protein USH1C/harmonin with the stabilized acetylated β-catenin, especially in nuclei. In HEK293T cells, overexpression of USH1C/harmonin significantly reduced cWnt signaling, but a USH1C-R31* mutated form did not. Concordantly, we observed an increase in cWnt signaling in dermal fibroblasts derived from an USH1C R31*/R80Pfs*69 patient compared with healthy donor cells. RNAseq analysis reveals that both the expression of genes related to the cWnt signaling pathway and cWnt target genes were significantly altered in USH1C patient-derived fibroblasts compared to healthy donor cells. Finally, we show that the altered cWnt signaling was reverted in USH1C patient fibroblast cells by the application of Ataluren, a small molecule suitable to induce translational read-through of nonsense mutations, hereby restoring some USH1C expression. Our results demonstrate a cWnt signaling phenotype in USH establishing USH1C/harmonin as a suppressor of the cWnt/β-catenin pathway.
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Affiliation(s)
- Jessica Schäfer
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nicole Wenck
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katharina Janik
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katarina Stingl
- Centre for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany,*Correspondence: Uwe Wolfrum,
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Retinal Structure and Function in a Knock-In Mouse Model for the FAM161A-p.Arg523* Human Nonsense Pathogenic Variant. OPHTHALMOLOGY SCIENCE 2022; 3:100229. [DOI: 10.1016/j.xops.2022.100229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/28/2022] [Accepted: 09/26/2022] [Indexed: 11/05/2022]
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13
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Lee RE, Lewis CA, He L, Bulik-Sullivan EC, Gallant SC, Mascenik TM, Dang H, Cholon DM, Gentzsch M, Morton LC, Minges JT, Theile JW, Castle NA, Knowles MR, Kimple AJ, Randell SH. Small molecule eRF3a degraders rescue CFTR nonsense mutations by promoting premature termination codon readthrough. J Clin Invest 2022; 132:154571. [PMID: 35900863 PMCID: PMC9479597 DOI: 10.1172/jci154571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 07/26/2022] [Indexed: 11/22/2022] Open
Abstract
The vast majority of people with cystic fibrosis (CF) are now eligible for CF transmembrane regulator (CFTR) modulator therapy. The remaining individuals with CF harbor premature termination codons (PTCs) or rare CFTR variants with limited treatment options. Although the clinical modulator response can be reliably predicted using primary airway epithelial cells, primary cells carrying rare CFTR variants are scarce. To overcome this obstacle, cell lines can be created by overexpression of mouse Bmi-1 and human TERT (hTERT). Using this approach, we developed 2 non-CF and 6 CF airway epithelial cell lines, 3 of which were homozygous for the W1282X PTC variant. The Bmi-1/hTERT cell lines recapitulated primary cell morphology and ion transport function. The 2 F508del-CFTR cell lines responded robustly to CFTR modulators, which was mirrored in the parent primary cells and in the cell donors’ clinical response. Cereblon E3 ligase modulators targeting eukaryotic release factor 3a (eRF3a) rescued W1282X-CFTR function to approximately 20% of WT levels and, when paired with G418, rescued G542X-CFTR function to approximately 50% of WT levels. Intriguingly, eRF3a degraders also diminished epithelial sodium channel (ENaC) function. These studies demonstrate that Bmi-1/hTERT cell lines faithfully mirrored primary cell responses to CFTR modulators and illustrate a therapeutic approach to rescue CFTR nonsense mutations.
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Affiliation(s)
- Rhianna E Lee
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Catherine A Lewis
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Lihua He
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Emily C Bulik-Sullivan
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Samuel C Gallant
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Teresa M Mascenik
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Hong Dang
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Deborah M Cholon
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Martina Gentzsch
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Lisa C Morton
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - John T Minges
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | | | - Neil A Castle
- Research and Development, Icagen, Durham, United States of America
| | - Michael R Knowles
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Adam J Kimple
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
| | - Scott H Randell
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, United States of America
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Huang S, Bhattacharya A, Ghelfi MD, Li H, Fritsch C, Chenoweth DM, Goldman YE, Cooperman BS. Ataluren binds to multiple protein synthesis apparatus sites and competitively inhibits release factor-dependent termination. Nat Commun 2022; 13:2413. [PMID: 35523781 PMCID: PMC9076611 DOI: 10.1038/s41467-022-30080-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 04/12/2022] [Indexed: 12/15/2022] Open
Abstract
Genetic diseases are often caused by nonsense mutations, but only one TRID (translation readthrough inducing drug), ataluren, has been approved for clinical use. Ataluren inhibits release factor complex (RFC) termination activity, while not affecting productive binding of near-cognate ternary complex (TC, aa-tRNA.eEF1A.GTP). Here we use photoaffinity labeling to identify two sites of ataluren binding within rRNA, proximal to the decoding center (DC) and the peptidyl transfer center (PTC) of the ribosome, which are directly responsible for ataluren inhibition of termination activity. A third site, within the RFC, has as yet unclear functional consequences. Using single molecule and ensemble fluorescence assays we also demonstrate that termination proceeds via rapid RFC-dependent hydrolysis of peptidyl-tRNA followed by slow release of peptide and tRNA from the ribosome. Ataluren is an apparent competitive inhibitor of productive RFC binding, acting at or before the hydrolysis step. We propose that designing more potent TRIDs which retain ataluren's low toxicity should target areas of the RFC binding site proximal to the DC and PTC which do not overlap the TC binding site.
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Affiliation(s)
- Shijie Huang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
- GSK, 14200 Shady Grove Rd, Rockville, MD, 20850, USA
| | - Arpan Bhattacharya
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mikel D Ghelfi
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hong Li
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Clark Fritsch
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - David M Chenoweth
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yale E Goldman
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Barry S Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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15
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Sanderlin EJ, Keenan MM, Mense M, Revenko AS, Monia BP, Guo S, Huang L. CFTR mRNAs with nonsense codons are degraded by the SMG6-mediated endonucleolytic decay pathway. Nat Commun 2022; 13:2344. [PMID: 35487895 PMCID: PMC9054838 DOI: 10.1038/s41467-022-29935-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 03/24/2022] [Indexed: 12/22/2022] Open
Abstract
Approximately 10% of cystic fibrosis patients harbor nonsense mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene which can generate nonsense codons in the CFTR mRNA and subsequently activate the nonsense-mediated decay (NMD) pathway resulting in rapid mRNA degradation. However, it is not known which NMD branches govern the decay of CFTR mRNAs containing nonsense codons. Here we utilize antisense oligonucleotides targeting NMD factors to evaluate the regulation of nonsense codon-containing CFTR mRNAs by the NMD pathway. We observe that CFTR mRNAs with nonsense codons G542X, R1162X, and W1282X, but not Y122X, require UPF2 and UPF3 for NMD. Furthermore, we demonstrate that all evaluated CFTR mRNAs harboring nonsense codons are degraded by the SMG6-mediated endonucleolytic pathway rather than the SMG5-SMG7-mediated exonucleolytic pathway. Finally, we show that upregulation of all evaluated CFTR mRNAs with nonsense codons by NMD pathway inhibition improves outcomes of translational readthrough therapy.
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Affiliation(s)
| | | | - Martin Mense
- Cystic Fibrosis Foundation Therapeutics Lab, Cystic Fibrosis Foundation, Lexington, MA, USA
| | | | | | - Shuling Guo
- Ionis Pharmaceuticals, Inc., Carlsbad, CA, USA
| | - Lulu Huang
- Ionis Pharmaceuticals, Inc., Carlsbad, CA, USA.
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16
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Martínez-Santamaría L, Maseda R, de Arriba MDC, Membrilla JA, Sigüenza AI, Mascías J, García M, Quintana L, Esteban-Rodríguez I, Hernández-Fernández CP, Illera N, Duarte B, Guerrero-Aspizúa S, Woodley DT, del Río M, de Lucas R, Larcher F, Escámez MJ. Evaluation of Systemic Gentamicin as Translational Readthrough Therapy for a Patient With Epidermolysis Bullosa Simplex With Muscular Dystrophy Owing to PLEC1 Pathogenic Nonsense Variants. JAMA Dermatol 2022; 158:439-443. [PMID: 35234827 PMCID: PMC8892370 DOI: 10.1001/jamadermatol.2022.0112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD) is an autosomal recessive disorder caused by pathogenic variants in PLEC1, which encodes plectin. It is characterized by mild mucocutaneous fragility and blistering and muscle weakness. Translational readthrough-inducing drugs, such as repurposed aminoglycoside antibiotics, may represent a valuable therapeutic alternative for untreatable rare diseases caused by nonsense variants. OBJECTIVE To evaluate whether systemic gentamicin, at a dose of 7.5 mg/kg/d for 14 consecutive days, is clinically beneficial in a patient with EBS-MD. DESIGN, SETTING, AND PARTICIPANTS A single patient in Madrid, Spain, received 2 treatment courses with gentamicin on July 2019 and February 2020 with a follow-up period of 120 and 150 days, respectively. RESULTS In this case report of a woman in her 30s with EBS-MD, before gentamicin treatment, the patient had mucocutaneous involvement, skeletal and respiratory muscle weakness, and myalgia that negatively affected her quality of life. Outcomes were evaluated with extensive laboratory tests and clinical scales. No nephrotoxic or ototoxic effects were detected after intravenous gentamicin administration. Gentamicin treatment was followed by plectin expression in the skin for at least 5 months. Although minimal changes were noted in skeletal muscle function (as measured by the Hammersmith functional motor scale and its expanded version: 6/40 to 7/40 and from 10/66 to 11/66, respectively) and respiratory musculature (maximal inspiratory and expiratory pressures D0 vs D16, MIP: 2.86 vs 3.63 KPa and MEP: 2.93 vs 4.63 KPa), myalgia disappeared (VAS dropped from 6 to 0), and quality of life improved (EuroQoL-5D-3L pain and anxiety dropped from 2 to 1). CONCLUSIONS AND RELEVANCE The findings of this single case report suggest that gentamicin treatment may help suppress PLEC1 premature termination codons and induce plectin expression in EBS-MD primary keratinocytes and skin. Our study suggests that gentamicin may play an important role in treating EBS-MD owing to nonsense variants.
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Affiliation(s)
- Lucía Martínez-Santamaría
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - Rocío Maseda
- Departamento de Dermatología, Hospital Universitario La Paz, Madrid, Spain
| | - María del Carmen de Arriba
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | | | | | - Javier Mascías
- Departamento de Neurología, Hospital Universitario La Paz, Madrid, Spain
| | - Marta García
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - Lucía Quintana
- Departamento de Dermatología, Hospital Universitario La Paz, Madrid, Spain
| | | | | | - Nuria Illera
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - Blanca Duarte
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - Sara Guerrero-Aspizúa
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - David T. Woodley
- Department of Dermatology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | | | - Raúl de Lucas
- Departamento de Dermatología, Hospital Universitario La Paz, Madrid, Spain
| | - Fernando Larcher
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
| | - María José Escámez
- Universidad Carlos III de Madrid, Departamento de Bioingeniería e Ingeniería Aeroespacial (UC3M), División de Biomedicina Epitelial, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII (CIBERER-ISCIII) - IIS-FJD, Madrid, Spain
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The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification. Hum Genet 2022; 141:709-735. [PMID: 35353227 PMCID: PMC9034986 DOI: 10.1007/s00439-022-02448-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Usher syndrome (USH) is the most common cause of deaf–blindness in humans, with a prevalence of about 1/10,000 (~ 400,000 people worldwide). Cochlear implants are currently used to reduce the burden of hearing loss in severe-to-profoundly deaf patients, but many promising treatments including gene, cell, and drug therapies to restore the native function of the inner ear and retinal sensory cells are under investigation. The traditional clinical classification of Usher syndrome defines three major subtypes—USH1, 2 and 3—according to hearing loss severity and onset, the presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa. Pathogenic variants of nine USH genes have been initially reported: MYO7A, USH1C, PCDH15, CDH23, and USH1G for USH1, USH2A, ADGRV1, and WHRN for USH2, and CLRN1 for USH3. Based on the co-occurrence of hearing and vision deficits, the list of USH genes has been extended to few other genes, but with limited supporting information. A consensus on combined criteria for Usher syndrome is crucial for the development of accurate diagnosis and to improve patient management. In recent years, a wealth of information has been obtained concerning the properties of the Usher proteins, related molecular networks, potential genotype–phenotype correlations, and the pathogenic mechanisms underlying the impairment or loss of hearing, balance and vision. The advent of precision medicine calls for a clear and more precise diagnosis of Usher syndrome, exploiting all the existing data to develop a combined clinical/genetic/network/functional classification for Usher syndrome.
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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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19
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Sainio MT, Rasila T, Molchanova SM, Järvilehto J, Torregrosa-Muñumer R, Harjuhaahto S, Pennonen J, Huber N, Herukka SK, Haapasalo A, Zetterberg H, Taira T, Palmio J, Ylikallio E, Tyynismaa H. Neurofilament Light Regulates Axon Caliber, Synaptic Activity, and Organelle Trafficking in Cultured Human Motor Neurons. Front Cell Dev Biol 2022; 9:820105. [PMID: 35237613 PMCID: PMC8883324 DOI: 10.3389/fcell.2021.820105] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/28/2021] [Indexed: 11/27/2022] Open
Abstract
Neurofilament light (NFL) is one of the proteins forming multimeric neuron-specific intermediate filaments, neurofilaments, which fill the axonal cytoplasm, establish caliber growth, and provide structural support. Dominant missense mutations and recessive nonsense mutations in the neurofilament light gene (NEFL) are among the causes of Charcot–Marie–Tooth (CMT) neuropathy, which affects the peripheral nerves with the longest axons. We previously demonstrated that a neuropathy-causing homozygous nonsense mutation in NEFL led to the absence of NFL in patient-specific neurons. To understand the disease-causing mechanisms, we investigate here the functional effects of NFL loss in human motor neurons differentiated from induced pluripotent stem cells (iPSC). We used genome editing to generate NEFL knockouts and compared them to patient-specific nonsense mutants and isogenic controls. iPSC lacking NFL differentiated efficiently into motor neurons with normal axon growth and regrowth after mechanical axotomy and contained neurofilaments. Electrophysiological analysis revealed that motor neurons without NFL fired spontaneous and evoked action potentials with similar characteristics as controls. However, we found that, in the absence of NFL, human motor neurons 1) had reduced axonal caliber, 2) the amplitude of miniature excitatory postsynaptic currents (mEPSC) was decreased, 3) neurofilament heavy (NFH) levels were reduced and no compensatory increases in other filament subunits were observed, and 4) the movement of mitochondria and to a lesser extent lysosomes was increased. Our findings elaborate the functional roles of NFL in human motor neurons. NFL is not only a structural protein forming neurofilaments and filling the axonal cytoplasm, but our study supports the role of NFL in the regulation of synaptic transmission and organelle trafficking. To rescue the NFL deficiency in the patient-specific nonsense mutant motor neurons, we used three drugs, amlexanox, ataluren (PTC-124), and gentamicin to induce translational read-through or inhibit nonsense-mediated decay. However, the drugs failed to increase the amount of NFL protein to detectable levels and were toxic to iPSC-derived motor neurons.
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Affiliation(s)
- Markus T Sainio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tiina Rasila
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Svetlana M Molchanova
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Julius Järvilehto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Rubén Torregrosa-Muñumer
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sandra Harjuhaahto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jana Pennonen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nadine Huber
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Sanna-Kaisa Herukka
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland.,Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom.,UK Dementia Research Institute at UCL, London, United Kingdom.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong, Hong Kong SAR, China
| | - Tomi Taira
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, Department of Veterinary Biosciences for Electrophysiology, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Johanna Palmio
- Neuromuscular Research Center, Tampere University Hospital and Tampere University, Tampere, Finland
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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20
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Ma Y, Sun W, Liu X, Ren J, Zhang X, Zhang R, Zhao L, Yang L, Wang G. Generation an induced pluripotent stem cell line SXMUi001-A derived from a hemophilia B patient carries variant F9 c.223C>T(p.R75X). Stem Cell Res 2022; 60:102684. [PMID: 35121195 DOI: 10.1016/j.scr.2022.102684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/10/2022] [Accepted: 01/17/2022] [Indexed: 11/19/2022] Open
Abstract
Hemophilia B (HB) is an X chromosome-linked recessive disorder caused by a quantitative or qualitative defect of coagulation zymogen factor IX. In this study, urine cells were collected from a patient with HB who carries variant F9 c.223C > T (p.R75X), and reprogrammed into induced pluripotent stem cells (iPSCs) using the reprogramming factors, OCT4, SOX2, m-MYC, and KLF4. The HB-iPSC line (SXMUi001-A) has characteristics similar to human embryonic stem cell, namely, pluripotency and the potential to differentiate into three germ layers. This cell line can be used as a disease model for exploring the molecular mechanism and readthrough treatment of HB.
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Affiliation(s)
- Yanchun Ma
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China
| | - Wenwen Sun
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China
| | - Xiue Liu
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China
| | - Juan Ren
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China
| | - Xialin Zhang
- Department of Hematology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030032, China
| | - Ruijuan Zhang
- Department of Hematology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030032, China
| | - Lidong Zhao
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China
| | - Linhua Yang
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China.
| | - Gang Wang
- Department of Hematology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi Province 030001, China.
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21
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Morren MA, Legius E, Giuliano F, Hadj-Rabia S, Hohl D, Bodemer C. Challenges in Treating Genodermatoses: New Therapies at the Horizon. Front Pharmacol 2022; 12:746664. [PMID: 35069188 PMCID: PMC8766835 DOI: 10.3389/fphar.2021.746664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 11/29/2021] [Indexed: 01/28/2023] Open
Abstract
Genodermatoses are rare inherited skin diseases that frequently affect other organs. They often have marked effects on wellbeing and may cause early death. Progress in molecular genetics and translational research has unravelled many underlying pathological mechanisms, and in several disorders with high unmet need, has opened the way for the introduction of innovative treatments. One approach is to intervene where cell-signaling pathways are dysregulated, in the case of overactive pathways by the use of selective inhibitors, or when the activity of an essential factor is decreased by augmenting a molecular component to correct disequilibrium in the pathway. Where inflammatory reactions have been induced by a genetically altered protein, another possible approach is to suppress the inflammation directly. Depending on the nature of the genodermatosis, the implicated protein or even on the particular mutation, to correct the consequences or the genetic defect, may require a highly personalised stratagem. Repurposed drugs, can be used to bring about a "read through" strategy especially where the genetic defect induces premature termination codons. Sometimes the defective protein can be replaced by a normal functioning one. Cell therapies with allogeneic normal keratinocytes or fibroblasts may restore the integrity of diseased skin and allogeneic bone marrow or mesenchymal cells may additionally rescue other affected organs. Genetic engineering is expanding rapidly. The insertion of a normal functioning gene into cells of the recipient is since long explored. More recently, genome editing, allows reframing, insertion or deletion of exons or disruption of aberrantly functioning genes. There are now several examples where these stratagems are being explored in the (pre)clinical phase of therapeutic trial programmes. Another stratagem, designed to reduce the severity of a given disease involves the use of RNAi to attenuate expression of a harmful protein by decreasing abundance of the cognate transcript. Most of these strategies are short-lasting and will thus require intermittent life-long administration. In contrast, insertion of healthy copies of the relevant gene or editing the disease locus in the genome to correct harmful mutations in stem cells is more likely to induce a permanent cure. Here we discuss the potential advantages and drawbacks of applying these technologies in patients with these genetic conditions. Given the severity of many genodermatoses, prevention of transmission to future generations remains an important goal including offering reproductive choices, such as preimplantation genetic testing, which can allow selection of an unaffected embryo for transfer to the uterus.
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Affiliation(s)
- Marie-Anne Morren
- Pediatric Dermatology Unit, Departments of Dermatology and Venereology and Pediatrics, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland
| | - Eric Legius
- Department for Human Genetics, University Hospitals Leuven, KU Leuven, ERN Genturis and ERN Skin, Leuven, Belgium
| | - Fabienne Giuliano
- Department of Medical Genetics, University Hospital Lausanne, Lausanne, Switzerland
| | - Smail Hadj-Rabia
- Department of Pediatric Dermatology and Dermatology, National Reference Centre for Genodermatosis and Rare Diseases of the Skin (MAGEC), Hôpital Necker-Enfants Malades, and Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, ERN Skin, Paris, France
| | - Daniel Hohl
- Department of Dermatology and Venereology, University Hospital Lausanne, University of Lausanne, Lausanne, Switzerland
| | - Christine Bodemer
- Department of Pediatric Dermatology and Dermatology, National Reference Centre for Genodermatosis and Rare Diseases of the Skin (MAGEC), Hôpital Necker-Enfants Malades, and Assistance Publique-Hôpitaux de Paris, Université Paris Descartes, ERN Skin, Paris, France
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22
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Yusuf IH, Garrett A, MacLaren RE, Issa PC. Retinal cadherins and the retinal cadherinopathies: Current concepts and future directions. Prog Retin Eye Res 2022; 90:101038. [DOI: 10.1016/j.preteyeres.2021.101038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022]
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23
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Gene Amplification as a Mechanism of Yeast Adaptation to Nonsense Mutations in Release Factor Genes. Genes (Basel) 2021; 12:genes12122019. [PMID: 34946968 PMCID: PMC8701342 DOI: 10.3390/genes12122019] [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: 10/16/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022] Open
Abstract
Protein synthesis (translation) is one of the fundamental processes occurring in the cells of living organisms. Translation can be divided into three key steps: initiation, elongation, and termination. In the yeast Saccharomyces cerevisiae, there are two translation termination factors, eRF1 and eRF3. These factors are encoded by the SUP45 and SUP35 genes, which are essential; deletion of any of them leads to the death of yeast cells. However, viable strains with nonsense mutations in both the SUP35 and SUP45 genes were previously obtained in several groups. The survival of such mutants clearly involves feedback control of premature stop codon readthrough; however, the exact molecular basis of such feedback control remain unclear. To investigate the genetic factors supporting the viability of these SUP35 and SUP45 nonsense mutants, we performed whole-genome sequencing of strains carrying mutant sup35-n and sup45-n alleles; while no common SNPs or indels were found in these genomes, we discovered a systematic increase in the copy number of the plasmids carrying mutant sup35-n and sup45-n alleles. We used the qPCR method which confirmed the differences in the relative number of SUP35 and SUP45 gene copies between strains carrying wild-type or mutant alleles of SUP35 and SUP45 genes. Moreover, we compare the number of copies of the SUP35 and SUP45 genes in strains carrying different nonsense mutant variants of these genes as a single chromosomal copy. qPCR results indicate that the number of mutant gene copies is increased compared to the wild-type control. In case of several sup45-n alleles, this was due to a disomy of the entire chromosome II, while for the sup35-218 mutation we observed a local duplication of a segment of chromosome IV containing the SUP35 gene. Taken together, our results indicate that gene amplification is a common mechanism of adaptation to nonsense mutations in release factor genes in yeast.
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24
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Wang C, Luo X, Wang Y, Liu Z, Wu S, Wang S, Lan X, Xu Q, Xu W, Yuan F, Wang A, Zeng F, Jia J, Chen Y. Novel Mutations of the ALMS1 Gene in Patients with Alström Syndrome. Intern Med 2021; 60:3721-3728. [PMID: 34148947 PMCID: PMC8710367 DOI: 10.2169/internalmedicine.6467-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective Alström syndrome is an autosomal recessive genetic disease caused by a mutation in the ALMS1 gene. Alström syndrome is clinically characterized by multisystem involvement, including sensorineural deafness, cone-rod dystrophy, nystagmus, obesity, insulin resistance, type 2 diabetes and hypogonadism. The diagnosis is thus challenging for patients without this characteristic set of clinical symptoms. We explored the effectiveness of whole-exome sequencing in the diagnosis of Alström syndrome. Methods A girl with symptoms of Alström syndrome was tested and diagnosed with the disease by whole-exome sequencing. Results Whole-exome sequencing revealed two novel variants, c.6160_6161insAT: p.Lys2054Asnfs*21 (exon 8) and c.10823_10824 delAG:p.Glu 3608Alafs*9 (exon16) in the ALMS1 gene, leading to premature termination codons and the domain of ALMS1 protein. Blood sample testing of her asymptomatic parents revealed them to be heterozygous carriers of the same mutations. Assembly showed that the mutations on both alleles were located in conserved sequences. A review of the ALMS1 gene nonsense mutation status was performed. Conclusion We herein report two novel variants of the ALMS1 gene discovered in a Chinese Alström syndrome patient that expand the mutational spectrum of ALMS1 and provided new insight into the molecular mechanism underlying Alström syndrome. Our findings add to the current knowledge concerning the diagnosis and treatment of Alström syndrome.
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Affiliation(s)
- Chunmei Wang
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Xiaona Luo
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Yilin Wang
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Zhao Liu
- Division of Pediatric Neurology, Department of Pediatrics, University of Illinois and Children's Hospital of Illinois, USA
| | - Shengnan Wu
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Simei Wang
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Xiaoping Lan
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Quanmei Xu
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Wuhen Xu
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Fang Yuan
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Anqi Wang
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
| | - Fanyi Zeng
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology & Shanghai Key Laboratory of Embryo and Reproduction Engineering, China
| | - Jia Jia
- Fuxiang Gene Engineering Research Institute, China
| | - Yucai Chen
- Department of Neurology, Children's Hospital of Shanghai, Shanghai JiaoTong University, China
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25
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Tseng MH, Konrad M, Ding JJ, Lin SH. Clinical and Genetic Approach to Renal Hypomagnesemia. Biomed J 2021; 45:74-87. [PMID: 34767995 PMCID: PMC9133307 DOI: 10.1016/j.bj.2021.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/03/2022] Open
Abstract
Magnesium (Mg2+) is an important intracellular cation and essential to maintain cell function including cell proliferation, immunity, cellular energy metabolism, protein and nucleic acid synthesis, and regulation of ion channels. Consequences of hypomagnesemia affecting multiple organs can be in overt or subtle presentations. Besides detailed history and complete physical examination, the assessment of urinary Mg2+ excretion is help to differentiate renal from extra-renal (gastrointestinal, tissue sequestration, and shifting) causes of hypomagnesemia. Renal hypomagnesemia can be caused by an increased glomerular filtration and impaired reabsorption in proximal tubular cells, thick ascending limb of the loop of Henle or distal convoluted tubules. A combination of renal Mg2+ wasting, familial history, age of onset, associated features, and exclusion of acquired etiologies point to inherited forms of renal hypomagnesemia. Based on clinical phenotypes, its definite genetic diagnosis can be simply grouped into specific, uncertain, and unknown gene mutations with a priority of genetic approach methods. An unequivocal molecular diagnosis could allow for prediction of clinical outcome, providing genetic counseling, avoiding unnecessary studies or interventions, and possibly uncovering the pathogenic mechanism. Given numerous identified genes responsible for Mg2+ transport in renal hypomagnesemia over the past two decades, several potential and specific molecular and cellular therapeutic strategies to correct hypomagnesemia are promising.
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Affiliation(s)
- Min-Hua Tseng
- Division of Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan; Department of Pediatrics, Xiamen Chang Gung Hospital, China
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital Münster, Münster, Germany
| | - Jhao-Jhuang Ding
- Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
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26
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Lee DDH, Cardinale D, Nigro E, Butler CR, Rutman A, Fassad MR, Hirst RA, Moulding D, Agrotis A, Forsythe E, Peckham D, Robson E, Smith CM, Somavarapu S, Beales PL, Hart SL, Janes SM, Mitchison HM, Ketteler R, Hynds RE, O'Callaghan C. Higher throughput drug screening for rare respiratory diseases: readthrough therapy in primary ciliary dyskinesia. Eur Respir J 2021; 58:13993003.00455-2020. [PMID: 33795320 PMCID: PMC8514977 DOI: 10.1183/13993003.00455-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/01/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Development of therapeutic approaches for rare respiratory diseases is hampered by the lack of systems that allow medium-to-high-throughput screening of fully differentiated respiratory epithelium from affected patients. This is a particular problem for primary ciliary dyskinesia (PCD), a rare genetic disease caused by mutations in genes that adversely affect ciliary movement and consequently mucociliary transport. Primary cell culture of basal epithelial cells from nasal brush biopsies followed by ciliated differentiation at the air-liquid interface (ALI) has proven to be a useful tool in PCD diagnostics but the technique's broader utility, including in pre-clinical PCD research, has been restricted by the limited number of basal cells that can be expanded from such biopsies. METHODS We describe an immunofluorescence screening method, enabled by extensive expansion of basal cells from PCD patients and the directed differentiation of these cells into ciliated epithelium in miniaturised 96-well transwell format ALI cultures. As proof-of-principle, we performed a personalised investigation in a patient with a rare and severe form of PCD (reduced generation of motile cilia), in this case caused by a homozygous nonsense mutation in the MCIDAS gene. RESULTS Initial analyses of ciliary ultrastructure, beat pattern and beat frequency in the 96-well transwell format ALI cultures indicate that a range of different PCD defects can be retained in these cultures. The screening system in our proof-of-principal investigation allowed drugs that induce translational readthrough to be evaluated alone or in combination with nonsense-mediated decay inhibitors. We observed restoration of basal body formation but not the generation of cilia in the patient's nasal epithelial cells in vitro. CONCLUSION: Our study provides a platform for higher throughput analyses of airway epithelia that is applicable in a range of settings and suggests novel avenues for drug evaluation and development in PCD caused by nonsense mutations.
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Affiliation(s)
- Dani Do Hyang Lee
- UCL Great Ormond Street Institute of Child Health, London, UK
- D.D.H. Lee and D. Cardinale contributed equally
| | - Daniela Cardinale
- UCL Great Ormond Street Institute of Child Health, London, UK
- D.D.H. Lee and D. Cardinale contributed equally
| | - Ersilia Nigro
- Lungs for Living Research Centre, UCL Respiratory, Division of Medicine, University College London, London, UK
| | - Colin R Butler
- Lungs for Living Research Centre, UCL Respiratory, Division of Medicine, University College London, London, UK
| | - Andrew Rutman
- Centre for PCD Diagnosis and Research, Dept of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Mahmoud R Fassad
- Ciliary Disease Section, Genetics and Genomic Medicine Research and Teaching Dept, UCL Great Ormond Street Institute of Child Health, London, UK
- Dept of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Robert A Hirst
- Centre for PCD Diagnosis and Research, Dept of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Dale Moulding
- Developmental Biology and Cancer, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Alexander Agrotis
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Elisabeth Forsythe
- Ciliary Disease Section, Genetics and Genomic Medicine Research and Teaching Dept, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Daniel Peckham
- Leeds Institute for Medical Research, University of Leeds, Leeds, UK
| | - Evie Robson
- Leeds Institute for Medical Research, University of Leeds, Leeds, UK
| | - Claire M Smith
- UCL Great Ormond Street Institute of Child Health, London, UK
| | | | - Philip L Beales
- Ciliary Disease Section, Genetics and Genomic Medicine Research and Teaching Dept, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Stephen L Hart
- Ciliary Disease Section, Genetics and Genomic Medicine Research and Teaching Dept, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Sam M Janes
- Lungs for Living Research Centre, UCL Respiratory, Division of Medicine, University College London, London, UK
| | - Hannah M Mitchison
- Ciliary Disease Section, Genetics and Genomic Medicine Research and Teaching Dept, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Robin Ketteler
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Robert E Hynds
- Lungs for Living Research Centre, UCL Respiratory, Division of Medicine, University College London, London, UK
- UCL Cancer Institute, University College London, London, UK
- R.E. Hynds and C. O'Callaghan contributed equally to this article as lead authors and supervised the work
| | - Christopher O'Callaghan
- UCL Great Ormond Street Institute of Child Health, London, UK
- Centre for PCD Diagnosis and Research, Dept of Respiratory Sciences, University of Leicester, Leicester, UK
- R.E. Hynds and C. O'Callaghan contributed equally to this article as lead authors and supervised the work
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27
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Popadynec M, Baradaran-Heravi A, Alford B, Cameron SA, Clinch K, Mason JM, Rendle PM, Zubkova OV, Gan Z, Liu H, Rebollo O, Whitfield DM, Yan F, Roberge M, Powell DA. Reducing the Toxicity of Designer Aminoglycosides as Nonsense Mutation Readthrough Agents for Therapeutic Targets. ACS Med Chem Lett 2021; 12:1486-1492. [PMID: 34531957 DOI: 10.1021/acsmedchemlett.1c00349] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/04/2021] [Indexed: 11/29/2022] Open
Abstract
A significant proportion of genetic disease cases arise from truncation of proteins caused by premature termination codons. In eukaryotic cells some aminoglycosides cause readthrough of premature termination codons during protein translation. Inducing readthrough of these codons can potentially be of therapeutic value in the treatment of numerous genetic diseases. A significant drawback to the repeated use of aminoglycosides as treatments is the lack of balance between their readthrough efficacy and toxicity. The synthesis and biological testing of designer aminoglycoside compounds is documented herein. We disclose the implementation of a strategy to reduce cellular toxicity and maintain readthrough activity of a library of compounds by modification of the overall cationic charge of the aminoglycoside scaffold through ring I modifications.
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Affiliation(s)
- Michael Popadynec
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Alireza Baradaran-Heravi
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | - Benjamin Alford
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Scott A. Cameron
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Keith Clinch
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jennifer M. Mason
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Phillip M. Rendle
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Olga V. Zubkova
- Ferrier Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Zhonghong Gan
- Sussex Research Laboratories, Inc., 100 Sussex Drive, Suite 1120B, Ottawa, Ontario K1A 0R6, Canada
| | - Hui Liu
- Sussex Research Laboratories, Inc., 100 Sussex Drive, Suite 1120B, Ottawa, Ontario K1A 0R6, Canada
| | - Oscar Rebollo
- Sussex Research Laboratories, Inc., 100 Sussex Drive, Suite 1120B, Ottawa, Ontario K1A 0R6, Canada
| | - Dennis M. Whitfield
- Sussex Research Laboratories, Inc., 100 Sussex Drive, Suite 1120B, Ottawa, Ontario K1A 0R6, Canada
| | - Fengyang Yan
- Sussex Research Laboratories, Inc., 100 Sussex Drive, Suite 1120B, Ottawa, Ontario K1A 0R6, Canada
| | - Michel Roberge
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | - David A. Powell
- Inception Sciences Canada, 210-887 Great Northern Way, Vancouver, British Columbia, V5T 4T5, Canada
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28
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Genetics, pathogenesis and therapeutic developments for Usher syndrome type 2. Hum Genet 2021; 141:737-758. [PMID: 34331125 DOI: 10.1007/s00439-021-02324-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/24/2021] [Indexed: 12/28/2022]
Abstract
Usher syndrome (USH) is a rare, autosomal recessively inherited disorder resulting in a combination of sensorineural hearing loss and a progressive loss of vision resulting from retinitis pigmentosa (RP), occasionally accompanied by an altered vestibular function. More and more evidence is building up indicating that also sleep deprivation, olfactory dysfunction, deficits in tactile perception and reduced sperm motility are part of the disease etiology. USH can be clinically classified into three different types, of which Usher syndrome type 2 (USH2) is the most prevalent. In this review, we, therefore, assess the genetic and clinical aspects, available models and therapeutic developments for USH2. Mutations in USH2A, ADGRV1 and WHRN have been described to be responsible for USH2, with USH2A being the most frequently mutated USH-associated gene, explaining 50% of all cases. The proteins encoded by the USH2 genes together function in a dynamic protein complex that, among others, is found at the photoreceptor periciliary membrane and at the base of the hair bundles of inner ear hair cells. To unravel the pathogenic mechanisms underlying USH2, patient-derived cellular models and animal models including mouse, zebrafish and drosophila, have been generated that all in part mimic the USH phenotype. Multiple cellular and genetic therapeutic approaches are currently under development for USH2, mainly focused on preserving or partially restoring the visual function of which one is already in the clinical phase. These developments are opening a new gate towards a possible treatment for USH2 patients.
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29
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Heinrichs B, Liu B, Zhang J, Meents JE, Le K, Erickson A, Hautvast P, Zhu X, Li N, Liu Y, Spehr M, Habel U, Rothermel M, Namer B, Zhang X, Lampert A, Duan G. The Potential Effect of Na v 1.8 in Autism Spectrum Disorder: Evidence From a Congenital Case With Compound Heterozygous SCN10A Mutations. Front Mol Neurosci 2021; 14:709228. [PMID: 34385907 PMCID: PMC8354588 DOI: 10.3389/fnmol.2021.709228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022] Open
Abstract
Apart from the most prominent symptoms in Autism spectrum disorder (ASD), namely deficits in social interaction, communication and repetitive behavior, patients often show abnormal sensory reactivity to environmental stimuli. Especially potentially painful stimuli are reported to be experienced in a different way compared to healthy persons. In our present study, we identified an ASD patient carrying compound heterozygous mutations in the voltage-gated sodium channel (VGSC) Na v 1.8, which is preferentially expressed in sensory neurons. We expressed both mutations, p.I1511M and p.R512∗, in a heterologous expression system and investigated their biophysical properties using patch-clamp recordings. The results of these experiments reveal that the p.R512∗ mutation renders the channel non-functional, while the p.I1511M mutation showed only minor effects on the channel's function. Behavioral experiments in a Na v 1.8 loss-of-function mouse model additionally revealed that Na v 1.8 may play a role in autism-like symptomatology. Our results present Na v 1.8 as a protein potentially involved in ASD pathophysiology and may therefore offer new insights into the genetic basis of this disease.
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Affiliation(s)
- Björn Heinrichs
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Baowen Liu
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jin Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jannis E. Meents
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Kim Le
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Andelain Erickson
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Petra Hautvast
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Xiwen Zhu
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Ningbo Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Liu
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Uniklinik RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at Systemic Levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hanover, Germany
| | - Barbara Namer
- Research Group Neurosciences of the Interdisciplinary Center for Clinical Research (IZKF), Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Xianwei Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Angelika Lampert
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Guangyou Duan
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
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Delivery of Genetic Information: Viral Vector and Nonviral Vector Gene Therapies. Int Ophthalmol Clin 2021; 61:35-57. [PMID: 34196317 DOI: 10.1097/iio.0000000000000360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Dębińska A. New Treatments for Atopic Dermatitis Targeting Skin Barrier Repair via the Regulation of FLG Expression. J Clin Med 2021; 10:jcm10112506. [PMID: 34198894 PMCID: PMC8200961 DOI: 10.3390/jcm10112506] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 12/16/2022] Open
Abstract
Atopic dermatitis (AD) is one of the most common chronic, inflammatory skin disorders with a complex etiology and a broad spectrum of clinical phenotypes. Despite its high prevalence and effect on the quality of life, safe and effective systemic therapies approved for long-term management of AD are limited. A better understanding of the pathogenesis of atopic dermatitis in recent years has contributed to the development of new therapeutic approaches that target specific pathophysiological pathways. Skin barrier dysfunction and immunological abnormalities are critical in the pathogenesis of AD. Recently, the importance of the downregulation of epidermal differentiation complex (EDC) molecules caused by external and internal stimuli has been extensively emphasized. The purpose of this review is to discuss the innovations in the therapy of atopic dermatitis, including biologics, small molecule therapies, and other drugs by highlighting regulatory mechanisms of skin barrier-related molecules, such as filaggrin (FLG) as a crucial pathway implicated in AD pathogenesis.
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Affiliation(s)
- Anna Dębińska
- 1st Department and Clinic of Paediatrics, Allergology and Cardiology, Wroclaw Medical University, Chałubińskiego 2a, 50-368 Wrocław, Poland
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Ataluren and aminoglycosides stimulate read-through of nonsense codons by orthogonal mechanisms. Proc Natl Acad Sci U S A 2021; 118:2020599118. [PMID: 33414181 PMCID: PMC7812769 DOI: 10.1073/pnas.2020599118] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nonsense mutations giving rise to premature stop codons (PSCs) cause many diseases, creating the need to develop safe and effective translational read-through–inducing drugs (TRIDs). The current best-characterized TRIDs are ataluren and aminoglycosides. Only ataluren has been approved for clinical use, albeit in a limited context. Here, we provide rate measurements of elementary steps in a single eukaryotic translation elongation cycle, allowing us to demonstrate that ataluren and the aminoglycoside G418 employ orthogonal mechanisms in stimulating PSC read-through: ataluren by inhibiting release factor-dependent termination of protein synthesis and G418 by increasing functional near-cognate transfer RNA mispairing, which permits continuation of synthesis. We conclude that development of new TRIDs combatting PSC diseases should prioritize those directed toward inhibiting termination. During protein synthesis, nonsense mutations, resulting in premature stop codons (PSCs), produce truncated, inactive protein products. Such defective gene products give rise to many diseases, including cystic fibrosis, Duchenne muscular dystrophy (DMD), and some cancers. Small molecule nonsense suppressors, known as TRIDs (translational read-through–inducing drugs), stimulate stop codon read-through. The best characterized TRIDs are ataluren, which has been approved by the European Medicines Agency for the treatment of DMD, and G418, a structurally dissimilar aminoglycoside. Previously [1], we applied a highly purified in vitro eukaryotic translation system to demonstrate that both aminoglycosides like G418 and more hydrophobic molecules like ataluren stimulate read-through by direct interaction with the cell’s protein synthesis machinery. Our results suggested that they might do so by different mechanisms. Here, we pursue this suggestion through a more-detailed investigation of ataluren and G418 effects on read-through. We find that ataluren stimulation of read-through derives exclusively from its ability to inhibit release factor activity. In contrast, G418 increases functional near-cognate tRNA mispairing with a PSC, resulting from binding to its tight site on the ribosome, with little if any effect on release factor activity. The low toxicity of ataluren suggests that development of new TRIDs exclusively directed toward inhibiting termination should be a priority in combatting PSC diseases. Our results also provide rate measurements of some of the elementary steps during the eukaryotic translation elongation cycle, allowing us to determine how these rates are modified when cognate tRNA is replaced by near-cognate tRNA ± TRIDs.
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Jamalpoor A, Othman A, Levtchenko EN, Masereeuw R, Janssen MJ. Molecular Mechanisms and Treatment Options of Nephropathic Cystinosis. Trends Mol Med 2021; 27:673-686. [PMID: 33975805 DOI: 10.1016/j.molmed.2021.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/15/2022]
Abstract
Nephropathic cystinosis is a severe, monogenic systemic disorder that presents early in life and leads to progressive organ damage, particularly affecting the kidneys. It is caused by mutations in the CTNS gene, which encodes the lysosomal transporter cystinosin, resulting in intralysosomal accumulation of cystine. Recent studies demonstrated that the loss of cystinosin is associated with disrupted autophagy dynamics, accumulation of distorted mitochondria, and increased oxidative stress, leading to abnormal proliferation and dysfunction of kidney cells. We discuss these molecular mechanisms driving nephropathic cystinosis. Further, we consider how unravelling molecular mechanisms supports the identification and development of new strategies for cystinosis by the use of small molecules, biologicals, and genetic rescue of the disease in vitro and in vivo.
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Affiliation(s)
- Amer Jamalpoor
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands
| | - Amr Othman
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands
| | - Elena N Levtchenko
- Department of Pediatric Nephrology & Growth and Regeneration, University Hospitals Leuven & KU Leuven, Leuven, Belgium
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands.
| | - Manoe J Janssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands.
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Dabrowski M, Bukowy-Bieryllo Z, Jackson CL, Zietkiewicz E. Properties of Non-Aminoglycoside Compounds Used to Stimulate Translational Readthrough of PTC Mutations in Primary Ciliary Dyskinesia. Int J Mol Sci 2021; 22:ijms22094923. [PMID: 34066907 PMCID: PMC8125088 DOI: 10.3390/ijms22094923] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/28/2021] [Accepted: 05/03/2021] [Indexed: 12/30/2022] Open
Abstract
Primary ciliary dyskinesia (PCD) is a rare disease with autosomal recessive inheritance, caused mostly by bi-allelic gene mutations that impair motile cilia structure and function. Currently, there are no causal treatments for PCD. In many disease models, translational readthrough of premature termination codons (PTC-readthrough) induced by aminoglycosides has been proposed as an effective way of restoring functional protein expression and reducing disease symptoms. However, variable outcomes of pre-clinical trials and toxicity associated with long-term use of aminoglycosides prompt the search for other compounds that might overcome these problems. Because a high proportion of PCD-causing variants are nonsense mutations, readthrough therapies are an attractive option. We tested a group of chemical compounds with known PTC-readthrough potential (ataluren, azithromycin, tylosin, amlexanox, and the experimental compound TC007), collectively referred to as non-aminoglycosides (NAGs). We investigated their PTC-readthrough efficiency in six PTC mutations found in Polish PCD patients, in the context of cell and cilia health, and in comparison to the previously tested aminoglycosides. The NAGs did not compromise the viability of the primary nasal respiratory epithelial cells, and the ciliary beat frequency was retained, similar to what was observed for gentamicin. In HEK293 cells transfected with six PTC-containing inserts, the tested compounds stimulated PTC-readthrough but with lower efficiency than aminoglycosides. The study allowed us to select compounds with minimal negative impact on cell viability and function but still the potential to induce PTC-readthrough.
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Affiliation(s)
- Maciej Dabrowski
- Institute of Human Genetics, Polish Academy of Sciences, 60-479 Poznan, Poland; (M.D.); (Z.B.-B.)
| | - Zuzanna Bukowy-Bieryllo
- Institute of Human Genetics, Polish Academy of Sciences, 60-479 Poznan, Poland; (M.D.); (Z.B.-B.)
| | - Claire L. Jackson
- Primary Ciliary Dyskinesia Centre, NIHR Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK;
- School of Clinical and Experimental Sciences, University of Southampton Faculty of Medicine, Southampton SO16 6YD, UK
| | - Ewa Zietkiewicz
- Institute of Human Genetics, Polish Academy of Sciences, 60-479 Poznan, Poland; (M.D.); (Z.B.-B.)
- Correspondence:
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35
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Luna S, Torices L, Mingo J, Amo L, Rodríguez-Escudero I, Ruiz-Ibarlucea P, Erramuzpe A, Cortés JM, Tejada MI, Molina M, Nunes-Xavier CE, López JI, Cid VJ, Pulido R. A global analysis of the reconstitution of PTEN function by translational readthrough of PTEN pathogenic premature termination codons. Hum Mutat 2021; 42:551-566. [PMID: 33600059 DOI: 10.1002/humu.24186] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/15/2021] [Accepted: 02/14/2021] [Indexed: 12/29/2022]
Abstract
The PTEN tumor suppressor gene is mutated with high incidence in tumors and in the germline of patients with cancer predisposition or with macrocephaly associated with autism. PTEN nonsense mutations generating premature termination codons (PTC) and producing nonfunctional truncated PTEN proteins are frequent in association with human disease. However, there are no studies addressing the restoration of full-length PTEN proteins from the PTC-mutated PTEN gene by translational readthrough. Here, we have performed a global translational and functional readthrough analysis of the complete collection of PTEN PTC somatic or hereditary mutations found in tumors or in the germline of patients (disease-associated PTEN PTCome), and we set standards for the analysis of the potential of readthrough functional reconstitution in disease-relevant genes. Our analysis indicates that prevalent pathogenic PTEN PTC mutations are susceptible to PTEN functional restoration in response to readthrough-inducing compounds. Comprehensive readthrough analyses of disease-associated PTComes will be valuable tools for the implementation of readthrough-based precision interventions in specific groups of patients.
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Affiliation(s)
- Sandra Luna
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Leire Torices
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Janire Mingo
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Laura Amo
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, UCM & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | | | - Asier Erramuzpe
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Jesús M Cortés
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
| | - María I Tejada
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, UCM & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - Caroline E Nunes-Xavier
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - José I López
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Department of Pathology, Cruces University Hospital, Barakaldo, Spain
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, UCM & Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - Rafael Pulido
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
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Torices L, de las Heras J, Arango-Lasprilla JC, Cortés JM, Nunes-Xavier CE, Pulido R. MMADHC premature termination codons in the pathogenesis of cobalamin D disorder: Potential of translational readthrough reconstitution. Mol Genet Metab Rep 2021; 26:100710. [PMID: 33552904 PMCID: PMC7847965 DOI: 10.1016/j.ymgmr.2021.100710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 11/21/2022] Open
Abstract
Mutations in the MMADHC gene cause cobalamin D disorder (cblD), an autosomal recessive inborn disease with defects in intracellular cobalamin (cbl, vitamin B12) metabolism. CblD patients present methylmalonic aciduria (MMA), homocystinuria (HC), or combined MMA/HC, and usually suffer developmental delay and cognitive deficits. The most frequent MMADHC genetic alterations associated with disease generate MMADHC truncated proteins, in many cases due to mutations that create premature termination codons (PTC). In this study, we have performed a comprehensive and global characterization of MMADHC protein variants generated by all annotated MMADHC PTC mutations in cblD patients, and analyzed the potential of inducible translational PTC readthrough to reconstitute MMADHC biosynthesis. MMADHC protein truncation caused by disease-associated PTC differentially affected the alternative usage of translation initiation sites, protein abundance, and subcellular localization of MMADHC. Aminoglycoside compounds induced translational PTC readthrough of MMADHC truncated variants, allowing the biosynthesis of full-length MMADHC in a PTC-specific manner. Our results suggest that translational PTC readthrough-based interventions could complement current therapies for cblD patients carrying specific MMADHC PTC mutations.
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Affiliation(s)
- Leire Torices
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | - Javier de las Heras
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Division of Pediatric Metabolism (CIBER-ER), Cruces University Hospital, Barakaldo, Spain
- Department of Pediatrics, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Juan Carlos Arango-Lasprilla
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Cell Biology and Histology, University of the Basque Country (UPV/EHU), Leioa, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
| | - Jesús M. Cortés
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Department of Cell Biology and Histology, University of the Basque Country (UPV/EHU), Leioa, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
| | - Caroline E. Nunes-Xavier
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Institute of Cancer Research, Oslo University Hospital Radiumhospitalet, N-0424 Oslo, Norway
| | - Rafael Pulido
- Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
- Ikerbasque, The Basque Foundation for Science, 48013 Bilbao, Spain
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Abstract
Inhibiting eukaryotic protein translation with small molecules is emerging as a powerful therapeutic strategy. The advantage of targeting cellular translational machinery is that it is required for the highly proliferative state of many neoplastic cells, replication of certain viruses, and ultimately the expression of a wide variety of protein targets. Although, this approach has been exploited to develop clinical agents, such as homoharringtonine (HHT, 1), used to treat chronic myeloid leukemia (CML), inhibiting components of the translational machinery is often associated with cytotoxic phenotypes. However, recent studies have demonstrated that certain small molecules can inhibit the translation of specific subsets of proteins, leading to lower cytotoxicity, and opening-up therapeutic opportunities for translation inhibitors to be deployed in indications beyond oncology and infectious disease. This review summarizes efforts to develop inhibitors of the eukaryotic translational machinery as therapeutic agents and highlights emerging opportunities for translation inhibitors in the future.
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Affiliation(s)
- Angela Fan
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
| | - Phillip P Sharp
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
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Selective toxicity of antibacterial agents-still a valid concept or do we miss chances and ignore risks? Infection 2020; 49:29-56. [PMID: 33367978 PMCID: PMC7851017 DOI: 10.1007/s15010-020-01536-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/04/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Selective toxicity antibacteribiotics is considered to be due to interactions with targets either being unique to bacteria or being characterized by a dichotomy between pro- and eukaryotic pathways with high affinities of agents to bacterial- rather than eukaryotic targets. However, the theory of selective toxicity oversimplifies the complex modes of action of antibiotics in pro- and eukaryotes. METHODS AND OBJECTIVE This review summarizes data describing multiple modes of action of antibiotics in eukaryotes. RESULTS Aminoglycosides, macrolides, oxazolidinones, chloramphenicol, clindamycin, tetracyclines, glycylcyclines, fluoroquinolones, rifampicin, bedaquillin, ß-lactams inhibited mitochondrial translation either due to binding to mitosomes, inhibition of mitochondrial RNA-polymerase-, topoisomerase 2ß-, ATP-synthesis, transporter activities. Oxazolidinones, tetracyclines, vancomycin, ß-lactams, bacitracin, isoniazid, nitroxoline inhibited matrix-metalloproteinases (MMP) due to chelation with zinc and calcium, whereas fluoroquinols fluoroquinolones and chloramphenicol chelated with these cations, too, but increased MMP activities. MMP-inhibition supported clinical efficacies of ß-lactams and daptomycin in skin-infections, and of macrolides, tetracyclines in respiratory-diseases. Chelation may have contributed to neuroprotection by ß-lactams and fluoroquinolones. Aminoglycosides, macrolides, chloramphenicol, oxazolidins oxazolidinones, tetracyclines caused read-through of premature stop codons. Several additional targets for antibiotics in human cells have been identified like interaction of fluoroquinolones with DNA damage repair in eukaryotes, or inhibition of mucin overproduction by oxazolidinones. CONCLUSION The effects of antibiotics on eukaryotes are due to identical mechanisms as their antibacterial activities because of structural and functional homologies of pro- and eukaryotic targets, so that the effects of antibiotics on mammals are integral parts of their overall mechanisms of action.
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Abstract
INTRODUCTION In the retina, noncoding RNA (ncRNA) plays an integral role in regulating apoptosis, inflammatory responses, visual perception, and photo-transduction, with altered levels reported in diseased states. AREAS COVERED MicroRNA (miRNA), a class of ncRNA, regulates post-transcription gene expression through the binding of complementary sites of target messenger RNA (mRNA) with resulting translational repression. Small-interfering RNA (siRNA) is a double-stranded RNA (dsRNA) that regulates gene expression, leading to selective silencing of genes through a process called RNA interference (RNAi). Another form of RNAi involves short hairpin RNA (shRNA). In age-related macular degeneration (AMD) and diabetic retinopathy (DR), miRNA has been implicated in the regulation of angiogenesis, oxidative stress, immune response, and inflammation. EXPERT OPINION Many RNA-based therapies in development are conveniently administered intravitreally, with the potential for pan-retinal effect. The majority of these RNA therapeutics are synthetic ncRNA's and hold promise for the treatment of AMD, DR, and inherited retinal diseases (IRDs). These RNA-based therapies include siRNA therapy with its high specificity, shRNA to 'knock down' autosomal dominant toxic gain of function-mutated genes, antisense oligonucleotides (ASOs), which can restore splicing defects, and translational read-through inducing drugs (TRIDs) to increase expression of full-length protein from genes with premature stop codons.
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Affiliation(s)
- Michael C Gemayel
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, USA
| | - Ashay D Bhatwadekar
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, USA
| | - Thomas Ciulla
- Department of Ophthalmology, Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis, IN, USA.,Preclinical and Clinical Development, Clearside Biomedical, Inc, Alpharetta, GA, USA.,Midwest Eye Institute, Indianapolis, IN, USA
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40
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Molecular Insights into Determinants of Translational Readthrough and Implications for Nonsense Suppression Approaches. Int J Mol Sci 2020; 21:ijms21249449. [PMID: 33322589 PMCID: PMC7764779 DOI: 10.3390/ijms21249449] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/27/2020] [Accepted: 12/05/2020] [Indexed: 02/07/2023] Open
Abstract
The fidelity of protein synthesis, a process shaped by several mechanisms involving specialized ribosome regions and external factors, ensures the precise reading of sense and stop codons. However, premature termination codons (PTCs) arising from mutations may, at low frequency, be misrecognized and result in PTC suppression, named ribosome readthrough, with production of full-length proteins through the insertion of a subset of amino acids. Since some drugs have been identified as readthrough inducers, this fidelity drawback has been explored as a therapeutic approach in several models of human diseases caused by nonsense mutations. Here, we focus on the mechanisms driving translation in normal and aberrant conditions, the potential fates of mRNA in the presence of a PTC, as well as on the results obtained in the research of efficient readthrough-inducing compounds. In particular, we describe the molecular determinants shaping the outcome of readthrough, namely the nucleotide and protein context, with the latter being pivotal to produce functional full-length proteins. Through the interpretation of experimental and mechanistic findings, mainly obtained in lysosomal and coagulation disorders, we also propose a scenario of potential readthrough-favorable features to achieve relevant rescue profiles, representing the main issue for the potential translatability of readthrough as a therapeutic strategy.
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Toualbi L, Toms M, Moosajee M. USH2A-retinopathy: From genetics to therapeutics. Exp Eye Res 2020; 201:108330. [PMID: 33121974 PMCID: PMC8417766 DOI: 10.1016/j.exer.2020.108330] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/21/2023]
Abstract
Bilallelic variants in the USH2A gene can cause Usher syndrome type 2 and non-syndromic retinitis pigmentosa. In both disorders, the retinal phenotype involves progressive rod photoreceptor loss resulting in nyctalopia and a constricted visual field, followed by subsequent cone degeneration, leading to the loss of central vision and severe visual impairment. The USH2A gene raises many challenges for researchers and clinicians due to a broad spectrum of mutations, a large gene size hampering gene therapy development and limited knowledge on its pathogenicity. Patients with Usher type 2 may benefit from hearing aids or cochlear implants to correct their hearing defects, but there are currently no approved treatments available for the USH2A-retinopathy. Several treatment strategies, including antisense oligonucleotides and translational readthrough inducing drugs, have shown therapeutic promise in preclinical studies. Further understanding of the pathogenesis and natural history of USH2A-related disorders is required to develop innovative treatments and design clinical trials based on reliable outcome measures. The present review will discuss the current knowledge about USH2A, the emerging therapeutics and existing challenges.
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Affiliation(s)
- Lyes Toualbi
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK; Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK; Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
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Schöneberg T, Liebscher I. Mutations in G Protein-Coupled Receptors: Mechanisms, Pathophysiology and Potential Therapeutic Approaches. Pharmacol Rev 2020; 73:89-119. [PMID: 33219147 DOI: 10.1124/pharmrev.120.000011] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
There are approximately 800 annotated G protein-coupled receptor (GPCR) genes, making these membrane receptors members of the most abundant gene family in the human genome. Besides being involved in manifold physiologic functions and serving as important pharmacotherapeutic targets, mutations in 55 GPCR genes cause about 66 inherited monogenic diseases in humans. Alterations of nine GPCR genes are causatively involved in inherited digenic diseases. In addition to classic gain- and loss-of-function variants, other aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, pseudogenes, gene fusion, and gene dosage, contribute to the repertoire of GPCR dysfunctions. However, the spectrum of alterations and GPCR involvement is probably much larger because an additional 91 GPCR genes contain homozygous or hemizygous loss-of-function mutations in human individuals with currently unidentified phenotypes. This review highlights the complexity of genomic alteration of GPCR genes as well as their functional consequences and discusses derived therapeutic approaches. SIGNIFICANCE STATEMENT: With the advent of new transgenic and sequencing technologies, the number of monogenic diseases related to G protein-coupled receptor (GPCR) mutants has significantly increased, and our understanding of the functional impact of certain kinds of mutations has substantially improved. Besides the classical gain- and loss-of-function alterations, additional aspects, such as biased signaling, trans-signaling, ectopic expression, allele variants of GPCRs, uniparental disomy, pseudogenes, gene fusion, and gene dosage, need to be elaborated in light of GPCR dysfunctions and possible therapeutic strategies.
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Affiliation(s)
- Torsten Schöneberg
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
| | - Ines Liebscher
- Rudolf Schönheimer Institute of Biochemistry, Molecular Biochemistry, Medical Faculty, Leipzig, Germany
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43
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Translational Read-Through Therapy of RPGR Nonsense Mutations. Int J Mol Sci 2020; 21:ijms21228418. [PMID: 33182541 PMCID: PMC7697989 DOI: 10.3390/ijms21228418] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 10/28/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
X-chromosomal retinitis pigmentosa (RP) frequently is caused by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene. We evaluated the potential of PTC124 (Ataluren, TranslamaTM) treatment to promote ribosomal read-through of premature termination codons (PTC) in RPGR. Expression constructs in HEK293T cells showed that the efficacy of read-through reagents is higher for UGA than UAA PTCs. We identified the novel hemizygous nonsense mutation c.1154T > A, p.Leu385* (NM_000328.3) causing a UAA PTC in RPGR and generated patient-derived fibroblasts. Immunocytochemistry of serum-starved control fibroblasts showed the RPGR protein in a dot-like expression pattern along the primary cilium. In contrast, RPGR was no longer detectable at the primary cilium in patient-derived cells. Applying PTC124 restored RPGR at the cilium in approximately 8% of patient-derived cells. RT-PCR and Western blot assays verified the pathogenic mechanisms underlying the nonsense variant. Immunofluorescence stainings confirmed the successful PTC124 treatment. Our results showed for the first time that PTC124 induces read-through of PTCs in RPGR and restores the localization of the RPGR protein at the primary cilium in patient-derived cells. These results may provide a promising new treatment option for patients suffering from nonsense mutations in RPGR or other genetic diseases.
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Crawford DK, Vanlandingham P, Schneider S, Goddeeris MM. Intravitreal administration of small molecule read-through agents demonstrate functional activity in a nonsense mutation mouse model. Exp Eye Res 2020; 201:108274. [PMID: 33017612 DOI: 10.1016/j.exer.2020.108274] [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: 06/12/2020] [Revised: 08/04/2020] [Accepted: 09/25/2020] [Indexed: 11/30/2022]
Abstract
The prevalence of nonsense mutations as a class within genetic diseases such as inherited retinal disorders (IRDs) presents an opportunity to develop a singular, common therapeutic agent for patients whose treatment options are otherwise limited. We propose a novel approach to addressing IRDs utilizing Eukaryotic Ribosome Selective Glycosides, ELX-01 and ELX-06, delivered to the eye by intravitreal (IVT) injection. We assessed read-through activity in vitro using a plasmid-based dual luciferase assay and in vivo in a mouse model of oculocutaneous albinism type 2. These models interrogate a naturally occurring R262X nonsense mutation in the OCA2 gene. ELX-01 and ELX-06 both produced a concentration-dependent increase in read-through of the OCA2 R262X mutation in the dual luciferase assay, with an effect at the top concentration which is superior to both gentamicin and G418. When testing both compounds in vivo, a single IVT injection produced a dose-dependent increase in melanin, consistent with compound read-through activity and functional restoration of the Oca2 protein. These results establish that ELX-01 and ELX-06 produce read-through of a premature stop codon in the OCA2 gene both in vitro and in vivo. The in vivo results suggest that these compounds can be dosed IVT to achieve read-through at the back of the eye. These data also suggest that ELX-01 or ELX-06 could serve as a common therapeutic agent across nonsense mutation-mediated IRDs and help to establish a target exposure range for development of a sustained release IVT formulation.
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Affiliation(s)
- Daniel K Crawford
- Eloxx Pharmaceuticals, Inc., 950 Winter Street, Waltham, MA, 02451, USA
| | | | - Susan Schneider
- Eloxx Pharmaceuticals, Inc., 950 Winter Street, Waltham, MA, 02451, USA
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45
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French LS, Mellough CB, Chen FK, Carvalho LS. A Review of Gene, Drug and Cell-Based Therapies for Usher Syndrome. Front Cell Neurosci 2020; 14:183. [PMID: 32733204 PMCID: PMC7363968 DOI: 10.3389/fncel.2020.00183] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
Usher syndrome is a genetic disorder causing neurosensory hearing loss and blindness from retinitis pigmentosa (RP). Adaptive techniques such as braille, digital and optical magnifiers, mobility training, cochlear implants, or other assistive listening devices are indispensable for reducing disability. However, there is currently no treatment to reduce or arrest sensory cell degeneration. There are several classes of treatments for Usher syndrome being investigated. The present article reviews the progress this research has made towards delivering commercial options for patients with Usher syndrome.
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Affiliation(s)
- Lucy S French
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
| | - Carla B Mellough
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, WA, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, WA, Australia
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
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46
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Langin L, Johnson TB, Kovács AD, Pearce DA, Weimer JM. A tailored Cln3 Q352X mouse model for testing therapeutic interventions in CLN3 Batten disease. Sci Rep 2020; 10:10591. [PMID: 32601357 PMCID: PMC7324379 DOI: 10.1038/s41598-020-67478-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 05/29/2020] [Indexed: 12/16/2022] Open
Abstract
CLN3 Batten disease (CLN3 disease) is a pediatric lysosomal storage disorder that presents with progressive blindness, motor and cognitive decline, seizures, and premature death. CLN3 disease results from mutations in CLN3 with the most prevalent mutation, a 966 bp deletion spanning exons 7-8, affecting ~ 75% of patients. Mouse models with complete Cln3 deletion or Cln3Δex7/8 mutation have been invaluable for learning about both the basic biology of CLN3 and the underlying pathological changes associated with CLN3 disease. These models, however, vary in their disease presentation and are limited in their utility for studying the role of nonsense mediated decay, and as a consequence, in testing nonsense suppression therapies and read-through compounds. In order to develop a model containing a disease-causing nonsense point mutation, here we describe a first-of-its-kind Cln3Q352X mouse model containing a c.1054C > T (p.Gln352Ter) point mutation. Similar to previously characterized Cln3 mutant mouse lines, this novel model shows pathological deficits throughout the CNS including accumulation of lysosomal storage material and glial activation, and has limited perturbation in behavioral measures. Thus, at the molecular and cellular level, this mouse line provides a valuable tool for testing nonsense suppression therapies or read through compounds in CLN3 disease in the future.
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Affiliation(s)
- Logan Langin
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th N, Sioux Falls, SD, 57104, USA
| | - Tyler B Johnson
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th N, Sioux Falls, SD, 57104, USA
| | - Attila D Kovács
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th N, Sioux Falls, SD, 57104, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
| | - David A Pearce
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th N, Sioux Falls, SD, 57104, USA.
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA.
| | - Jill M Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, 2301 E. 60th N, Sioux Falls, SD, 57104, USA.
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA.
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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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Didiasova M, Banning A, Brennenstuhl H, Jung-Klawitter S, Cinquemani C, Opladen T, Tikkanen R. Succinic Semialdehyde Dehydrogenase Deficiency: An Update. Cells 2020; 9:cells9020477. [PMID: 32093054 PMCID: PMC7072817 DOI: 10.3390/cells9020477] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADH-D) is a genetic disorder that results from the aberrant metabolism of the neurotransmitter γ-amino butyric acid (GABA). The disease is caused by impaired activity of the mitochondrial enzyme succinic semialdehyde dehydrogenase. SSADH-D manifests as varying degrees of mental retardation, autism, ataxia, and epileptic seizures, but the clinical picture is highly heterogeneous. So far, there is no approved curative therapy for this disease. In this review, we briefly summarize the molecular genetics of SSADH-D, the past and ongoing clinical trials, and the emerging features of the molecular pathogenesis, including redox imbalance and mitochondrial dysfunction. The main aim of this review is to discuss the potential of further therapy approaches that have so far not been tested in SSADH-D, such as pharmacological chaperones, read-through drugs, and gene therapy. Special attention will also be paid to elucidating the role of patient advocacy organizations in facilitating research and in the communication between researchers and patients.
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Affiliation(s)
- Miroslava Didiasova
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
| | - Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
| | - Heiko Brennenstuhl
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | - Sabine Jung-Klawitter
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | | | - Thomas Opladen
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Children’s Hospital Heidelberg, 69120 Heidelberg, Germany; (H.B.); (S.J.-K.); (T.O.)
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; (M.D.); (A.B.)
- Correspondence: ; Tel.: +49-641-9947-420
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Screening Readthrough Compounds to Suppress Nonsense Mutations: Possible Application to β-Thalassemia. J Clin Med 2020; 9:jcm9020289. [PMID: 31972957 PMCID: PMC7073686 DOI: 10.3390/jcm9020289] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/08/2020] [Accepted: 01/13/2020] [Indexed: 02/07/2023] Open
Abstract
Several types of thalassemia (including β039-thalassemia) are caused by nonsense mutations in genes controlling globin production, leading to premature translation termination and mRNA destabilization mediated by the nonsense mediated mRNA decay. Drugs (for instance, aminoglycosides) can be designed to suppress premature translation termination by inducing readthrough (or nonsense suppression) at the premature termination codon. These findings have introduced new hopes for the development of a pharmacologic approach to cure this genetic disease. In the present review, we first summarize the principle and current status of the chemical relief for the expression of functional proteins from genes otherwise unfruitful for the presence of nonsense mutations. Second, we compare data available on readthrough molecules for β0-thalassemia. The examples reported in the review strongly suggest that ribosomal readthrough should be considered as a therapeutic approach for the treatment of β0-thalassemia caused by nonsense mutations. Concluding, the discovery of molecules, exhibiting the property of inducing β-globin, such as readthrough compounds, is of great interest and represents a hope for several patients, whose survival will depend on the possible use of drugs rendering blood transfusion and chelation therapy unnecessary.
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50
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Ataluren for the Treatment of Usher Syndrome 2A Caused by Nonsense Mutations. Int J Mol Sci 2019; 20:ijms20246274. [PMID: 31842393 PMCID: PMC6940777 DOI: 10.3390/ijms20246274] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 12/18/2022] Open
Abstract
The identification of genetic defects that underlie inherited retinal diseases (IRDs) paves the way for the development of therapeutic strategies. Nonsense mutations caused approximately 12% of all IRD cases, resulting in a premature termination codon (PTC). Therefore, an approach that targets nonsense mutations could be a promising pharmacogenetic strategy for the treatment of IRDs. Small molecules (translational read-through inducing drugs; TRIDs) have the potential to mediate the read-through of nonsense mutations by inducing expression of the full-length protein. We provide novel data on the read-through efficacy of Ataluren on a nonsense mutation in the Usher syndrome gene USH2A that causes deaf-blindness in humans. We demonstrate Ataluren´s efficacy in both transiently USH2AG3142*-transfected HEK293T cells and patient-derived fibroblasts by restoring USH2A protein expression. Furthermore, we observed enhanced ciliogenesis in patient-derived fibroblasts after treatment with TRIDs, thereby restoring a phenotype that is similar to that found in healthy donors. In light of recent findings, we validated Ataluren´s efficacy to induce read-through on a nonsense mutation in USH2A-related IRD. In line with published data, our findings support the use of patient-derived fibroblasts as a platform for the validation of preclinical therapies. The excellent biocompatibility combined with sustained read-through efficacy makes Ataluren an ideal TRID for treating nonsense mutations based IRDs.
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