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Ruan J, Yu X, Xu H, Cui W, Zhang K, Liu C, Sun W, Huang X, An L, Zhang Y. Suppressor tRNA in gene therapy. SCIENCE CHINA. LIFE SCIENCES 2024:10.1007/s11427-024-2613-y. [PMID: 38926247 DOI: 10.1007/s11427-024-2613-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/08/2024] [Indexed: 06/28/2024]
Abstract
Suppressor tRNAs are engineered or naturally occurring transfer RNA molecules that have shown promise in gene therapy for diseases caused by nonsense mutations, which result in premature termination codons (PTCs) in coding sequence, leading to truncated, often nonfunctional proteins. Suppressor tRNAs can recognize and pair with these PTCs, allowing the ribosome to continue translation and produce a full-length protein. This review introduces the mechanism and development of suppressor tRNAs, compares suppressor tRNAs with other readthrough therapies, discusses their potential for clinical therapy, limitations, and obstacles. We also summarize the applications of suppressor tRNAs in both in vitro and in vivo, offering new insights into the research and treatment of nonsense mutation diseases.
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Affiliation(s)
- Jingjing Ruan
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Liangzhu Laboratory, Hangzhou, 310000, China
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Xiaoxiao Yu
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Huixia Xu
- Department of Thoracic and Cardiovascular Surgery, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Wenrui Cui
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Kaiye Zhang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Chenyang Liu
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China
| | - Wenlong Sun
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Xiaodan Huang
- Eye Center, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Lei An
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China.
| | - Yue Zhang
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Liangzhu Laboratory, Hangzhou, 310000, China.
- Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 311121, China.
- Translational Medicine Center, Huaihe Hospital of Henan University, Henan University, Kaifeng, 475000, China.
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Spelier S, van Doorn EPM, van der Ent CK, Beekman JM, Koppens MAJ. Readthrough compounds for nonsense mutations: bridging the translational gap. Trends Mol Med 2023; 29:297-314. [PMID: 36828712 DOI: 10.1016/j.molmed.2023.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/28/2022] [Accepted: 01/19/2023] [Indexed: 02/24/2023]
Abstract
Approximately 10% of all pathological mutations are nonsense mutations that are responsible for several severe genetic diseases for which no treatment regimens are currently available. The most widespread strategy for treating nonsense mutations is by enhancing ribosomal readthrough of premature termination codons (PTCs) to restore the production of the full-length protein. In the past decade several compounds with readthrough potential have been identified. However, although preclinical results on these compounds are promising, clinical studies have not yielded positive outcomes. We review preclinical and clinical research related to readthrough compounds and characterize factors that contribute to the observed translational gap.
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Affiliation(s)
- Sacha Spelier
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands
| | - Eveline P M van Doorn
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands
| | - Cornelis K van der Ent
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands
| | - Jeffrey M Beekman
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands; Center for Living Technologies, Eindhoven-Wageningen-Utrecht Alliance, Utrecht, The Netherlands
| | - Martijn A J Koppens
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands; Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands.
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3
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Song J, Dong L, Sun H, Luo N, Huang Q, Li K, Shen X, Jiang Z, Lv Z, Peng L, Zhang M, Wang K, Liu K, Hong J, Yi C. CRISPR-free, programmable RNA pseudouridylation to suppress premature termination codons. Mol Cell 2023; 83:139-155.e9. [PMID: 36521489 DOI: 10.1016/j.molcel.2022.11.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/03/2022] [Accepted: 11/14/2022] [Indexed: 12/15/2022]
Abstract
Nonsense mutations, accounting for >20% of disease-associated mutations, lead to premature translation termination. Replacing uridine with pseudouridine in stop codons suppresses translation termination, which could be harnessed to mediate readthrough of premature termination codons (PTCs). Here, we present RESTART, a programmable RNA base editor, to revert PTC-induced translation termination in mammalian cells. RESTART utilizes an engineered guide snoRNA (gsnoRNA) and the endogenous H/ACA box snoRNP machinery to achieve precise pseudouridylation. We also identified and optimized gsnoRNA scaffolds to increase the editing efficiency. Unexpectedly, we found that a minor isoform of pseudouridine synthase DKC1, lacking a C-terminal nuclear localization signal, greatly improved the PTC-readthrough efficiency. Although RESTART induced restricted off-target pseudouridylation, they did not change the coding information nor the expression level of off-targets. Finally, RESTART enables robust pseudouridylation in primary cells and achieves functional PTC readthrough in disease-relevant contexts. Collectively, RESTART is a promising RNA-editing tool for research and therapeutics.
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Affiliation(s)
- Jinghui Song
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Liting Dong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, PRC
| | - Hanxiao Sun
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Nan Luo
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Qiang Huang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Kai Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, PRC; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PRC
| | - Xiaowen Shen
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, PRC
| | - Zhe Jiang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Zhicong Lv
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Luxin Peng
- College of Chemistry and Molecular Engineering, Peking University, Beijing, PRC
| | | | - Kun Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC
| | - Ke Liu
- Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, PRC
| | - Jiaxu Hong
- Department of Ophthalmology, Eye and Ear, Nose, Throat Hospital of Fudan University, Shanghai, PRC
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, PRC; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, PRC; Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, PRC.
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Ataluren-Promising Therapeutic Premature Termination Codon Readthrough Frontrunner. Pharmaceuticals (Basel) 2021; 14:ph14080785. [PMID: 34451881 PMCID: PMC8398184 DOI: 10.3390/ph14080785] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 07/30/2021] [Accepted: 08/06/2021] [Indexed: 02/08/2023] Open
Abstract
Around 12% of hereditary disease-causing mutations are in-frame nonsense mutations. The expression of genes containing nonsense mutations potentially leads to the production of truncated proteins with residual or virtually no function. However, the translation of transcripts containing premature stop codons resulting in full-length protein expression can be achieved using readthrough agents. Among them, only ataluren was approved in several countries to treat nonsense mutation Duchenne muscular dystrophy (DMD) patients. This review summarizes ataluren’s journey from its identification, via first in vitro activity experiments, to clinical trials in DMD, cystic fibrosis, and aniridia. Additionally, data on its pharmacokinetics and mechanism of action are presented. The range of diseases with underlying nonsense mutations is described for which ataluren therapy seems to be promising. What is more, experiments in which ataluren did not show its readthrough activity are also included, and reasons for their failures are discussed.
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Schilff M, Sargsyan Y, Hofhuis J, Thoms S. Stop Codon Context-Specific Induction of Translational Readthrough. Biomolecules 2021; 11:biom11071006. [PMID: 34356630 PMCID: PMC8301745 DOI: 10.3390/biom11071006] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/11/2022] Open
Abstract
Premature termination codon (PTC) mutations account for approximately 10% of pathogenic variants in monogenic diseases. Stimulation of translational readthrough, also known as stop codon suppression, using translational readthrough-inducing drugs (TRIDs) may serve as a possible therapeutic strategy for the treatment of genetic PTC diseases. One important parameter governing readthrough is the stop codon context (SCC)-the stop codon itself and the nucleotides in the vicinity of the stop codon on the mRNA. However, the quantitative influence of the SCC on treatment outcome and on appropriate drug concentrations are largely unknown. Here, we analyze the readthrough-stimulatory effect of various readthrough-inducing drugs on the SCCs of five common premature termination codon mutations of PEX5 in a sensitive dual reporter system. Mutations in PEX5, encoding the peroxisomal targeting signal 1 receptor, can cause peroxisomal biogenesis disorders of the Zellweger spectrum. We show that the stop context has a strong influence on the levels of readthrough stimulation and impacts the choice of the most effective drug and its concentration. These results highlight potential advantages and the personalized medicine nature of an SCC-based strategy in the therapy of rare diseases.
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Affiliation(s)
- Mirco Schilff
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Yelena Sargsyan
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
| | - Julia Hofhuis
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
| | - Sven Thoms
- Department of Child and Adolescent Health, University Medical Center, 37075 Göttingen, Germany; (M.S.); (Y.S.); (J.H.)
- Department of Biochemistry and Molecular Medicine, Medical School, Bielefeld University, 33615 Bielefeld, Germany
- Correspondence: ; Tel.: +49-521-106-86502
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Luisman T, Smith T, Ritchie S, Malone KE. Genetic epidemiology approach to estimating birth incidence and current disease prevalence for rhizomelic chondrodysplasia punctata. Orphanet J Rare Dis 2021; 16:300. [PMID: 34229749 PMCID: PMC8258949 DOI: 10.1186/s13023-021-01889-z] [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: 02/05/2021] [Accepted: 05/24/2021] [Indexed: 11/17/2022] Open
Abstract
Background Rhizomelic chondrodysplasia punctata (RCDP) is an inherited ultra-rare disease which results in severely impaired physical and mental development. Mutations in one of five genes involved in plasmalogen biosynthesis have been reported to drive disease pathology. Estimates of disease incidence have been extremely challenging due to the rarity of the disorder, preventing an understanding of the unmet medical need. To address this, we have prepared a disease incidence and prevalence model based on genetic epidemiology approaches to estimate the total number of RCDP patients affected, and their demographic characteristics. Results Extraction of allelic frequencies for known and predicted pathogenic variants in PEX7, GNPAT, AGPS, FAR1, PEX5 (limited to the PTS2 domain encoding region) genes, from large-scale human genetic diversity datasets (TopMed and gnomAD) revealed the mutational landscape contributing to the RCDP patient population in the US and Europe. We computed genetic prevalence to derive birth incidence for RCDP and modeled the impact to life expectancy to obtain high confidence estimates of disease prevalence. Our population genetics-based model indicates PEX7 variants are expected to contribute to the majority of RCDP cases in both the US and Europe; closely aligning with clinical reports. Furthermore, this model provides estimates for RCDP subtypes due to mutations in other genes, including exceedingly rare subtypes. Conclusion In total, the estimated number of RCDP patients in the US and the five largest European countries (UK, Germany, France, Italy and Spain) is between 516 and 847 patients, all under the age of 35 years old. This model provides a quantitative framework for better understanding the unmet medical need in RCDP, to help guide disease awareness and diagnosis efforts for this specific patient group. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01889-z.
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Affiliation(s)
| | - Tara Smith
- Med-Life Discoveries, Saskatoon, SK, Canada.
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Gaina G, Popa (Gruianu) A. Muscular dystrophy: Experimental animal models and therapeutic approaches (Review). Exp Ther Med 2021; 21:610. [PMID: 33936267 PMCID: PMC8082581 DOI: 10.3892/etm.2021.10042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022] Open
Abstract
The muscular dystrophies are a heterogeneous group of genetically inherited diseases characterized by muscle weakness and progressive wasting, which can cause premature death in severe forms. Although >30 years have passed since the identification of the first protein involved in a type of muscular dystrophy, there is no effective treatment for these disabling disorders. In the last decade, several novel therapeutic approaches have been developed and investigated as promising therapeutic approaches aimed to ameliorate the dystrophic phenotype either by restoring dystrophin expression or by compensating for dystrophin deficiency. Concurrently, with the development of therapeutic approaches, in addition to naturally occurring animal models, a wide range of genetically engineered animal models has been generated. The use of animals as models of muscular dystrophies has greatly improved the understanding of the pathogenicity of these diseases and has proven useful in gene therapy studies. In this review, we summarize these latest innovative therapeutic approaches to muscular dystrophies and the usefulness of the various most common experimental animal models.
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Affiliation(s)
- Gisela Gaina
- Laboratory of Cell Biology, Neuroscience and Experimental Myology, ‘Victor Babes’ National Institute of Pathology, 050096 Bucharest, Romania
- Department of Biochemistry and Molecular Biology, University of Bucharest, 050095 Bucharest, Romania
| | - Alexandra Popa (Gruianu)
- Laboratory of Cell Biology, Neuroscience and Experimental Myology, ‘Victor Babes’ National Institute of Pathology, 050096 Bucharest, Romania
- Department of Animal Production and Public Health, University of Agronomic Sciences and Veterinary Medicine of Bucharest, 050097 Bucharest, Romania
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Tarrasó G, Real-Martinez A, Parés M, Romero-Cortadellas L, Puigros L, Moya L, de Luna N, Brull A, Martín MA, Arenas J, Lucia A, Andreu AL, Barquinero J, Vissing J, Krag TO, Pinós T. Absence of p.R50X Pygm read-through in McArdle disease cellular models. Dis Model Mech 2020; 13:dmm.043281. [PMID: 31848135 PMCID: PMC6994938 DOI: 10.1242/dmm.043281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/05/2019] [Indexed: 12/13/2022] Open
Abstract
McArdle disease is an autosomal recessive disorder caused by the absence of muscle glycogen phosphorylase, which leads to blocked muscle glycogen breakdown. We used three different cellular models to evaluate the efficiency of different read-through agents (including amlexanox, Ataluren, RTC13 and G418) in McArdle disease. The first model consisted of HeLa cells transfected with two different GFP-PYGM constructs presenting the Pygm p.R50X mutation (GFP-PYGM p.R50X and PYGM Ex1-GFP p.R50X). The second cellular model was based on the creation of HEK293T cell lines stably expressing the PYGM Ex1-GFP p.R50X construct. As these plasmids encode murine Pygm cDNA without any intron sequence, their transfection in cells would allow for analysis of the efficacy of read-through agents with no concomitant nonsense-mediated decay interference. The third model consisted of skeletal muscle cultures derived from the McArdle mouse model (knock-in for the p.R50X mutation in the Pygm gene). We found no evidence of read-through at detectable levels in any of the models evaluated. We performed a literature search and compared the premature termination codon context sequences with reported positive and negative read-through induction, identifying a potential role for nucleotide positions −9, −8, −3, −2, +13 and +14 (the first nucleotide of the stop codon is assigned as +1). The Pygm p.R50X mutation presents TGA as a stop codon, G nucleotides at positions −1 and −9, and a C nucleotide at −3, which potentially generate a good context for read-through induction, counteracted by the presence of C at −2 and its absence at +4. Summary: Here, we evaluated the efficiency of different read-through agents in McArdle disease cell culture models, revealing that read-through compounds do not restore full-length muscle glycogen phosphorylase.
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Affiliation(s)
- Guillermo Tarrasó
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Alberto Real-Martinez
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Marta Parés
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Lídia Romero-Cortadellas
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Laura Puigros
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Laura Moya
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Noemí de Luna
- Laboratori de Malalties Neuromusculars, Institut de Recerca Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona 08041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Astrid Brull
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Miguel Angel Martín
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Joaquin Arenas
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Alejandro Lucia
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Faculty of Sport Sciences, European University, Madrid 28670, Spain
| | - Antoni L Andreu
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Jordi Barquinero
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Thomas O Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Tomàs Pinós
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain .,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
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Serum starvation enhances nonsense mutation readthrough. J Mol Med (Berl) 2019; 97:1695-1710. [PMID: 31786671 DOI: 10.1007/s00109-019-01847-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/03/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022]
Abstract
Of all genetic mutations causing human disease, premature termination codons (PTCs) that result from splicing defaults, insertions, deletions, and point mutations comprise around 30%. From these mutations, around 11% are a substitution of a single nucleotide that change a codon into a premature termination codon. These types of mutations affect several million patients suffering from a large variety of genetic diseases, ranging from relatively common inheritable cancer syndromes to muscular dystrophy or very rare neuro-metabolic disorders. Over the past three decades, genetic and biochemical studies have revealed that certain antibiotics and other synthetic molecules can act as nonsense mutation readthrough-inducing drugs. These compounds bind a specific site on the rRNA and, as a result, the stop codon is misread and an amino acid (that may or may not differ from the wild-type amino acid) is inserted and translation occurs through the premature termination codon. This strategy has great therapeutic potential. Unfortunately, many readthrough agents are toxic and cannot be administered over the extended period usually required for the chronic treatment of genetic diseases. Furthermore, readthrough compounds only restore protein production in very few disease models and the readthrough levels are usually low, typically achieving no more than 5% of normal protein expression. Efforts have been made over the years to overcome these obstacles so that readthrough treatment can become clinically relevant. Here, we present the creation of a stable cell line system that constitutively expresses our dual-reporter vector harboring two cancer initiating nonsense mutations in the adenomatous polyposis coli (APC) gene. This system will be used as an improved screening method for isolation of new nonsense mutation readthrough inducers. Using these cell lines as well as colorectal cancer cell lines, we demonstrate that serum starvation enhances drug-induced readthrough activity, an observation which may prove beneficial in a therapeutic scenario that requires higher levels of the restored protein. KEY MESSAGES: Nonsense mutations affects millions of people worldwide. We have developed a nonsense mutation read-through screening tool. We find that serum starvation enhances antibiotic-induced nonsense mutation read-through. Our results suggest new strategies for enhancing nonsense mutation read-through that may have positive effects on a large number of patients.
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10
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Wang H, Li Q, Zhang Z, Xiao P, Li L, Jiang Q. Functional Studies on Novel RET Mutations and Their Implications for Genetic Counseling for Hirschsprung Disease. Front Genet 2019; 10:924. [PMID: 31649719 PMCID: PMC6792140 DOI: 10.3389/fgene.2019.00924] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022] Open
Abstract
Hirschsprung disease (HSCR) is a genetic disorder characterized by the absence of ganglion cells in the gut. RET is considered to be the main susceptibility gene. In our previous screening of 83 HSCR patients, targeted exome sequencing identified nine rare variants of RET, most of which were new discoveries. Here, we performed in vitro arrays with functional studies to investigate their effects. Two variants (p.R77C and p.R67insL) were demonstrated to disrupt the glycosylation of RET and affect its subcellular localization. Three nonsense mutations (p.W85X, p.E252X, and p.Y263X) could not produce detectable RET full-length protein, and the other three mutations (p.R770X, p.Q860X, and p.V778Afs*1) were translated into truncated proteins of predicted sizes. One canonical splice acceptor site mutation (c.2802-2 A > G) was verified to affect gene regulation through aberrant splicing. In addition, we explored the effects of read-through reagents on RET nonsense mutations and showed that G418 significantly increased the full-length RET protein expression of p.Y263X in a dose-dependent manner, together with a mild recovery of p-ERK and p-STAT3. Our data provide a functional analysis of novel RET mutations and suggest that all of the rare variants detected from patients with clinically severe HSCR are indeed pathogenic. Thus, our findings have implications for proper genetic counseling.
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Affiliation(s)
- Hui Wang
- Department of Medical Genetics, Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
| | - Qi Li
- Department of General Surgery, Capital Institute of Pediatrics Affiliated Children's Hospital, Beijing, China
| | - Zhen Zhang
- Department of General Surgery, Capital Institute of Pediatrics Affiliated Children's Hospital, Beijing, China
| | - Ping Xiao
- Department of Pathology, Capital Institute of Pediatrics Affiliated Children's Hospital, Beijing, China
| | - Long Li
- Department of General Surgery, Capital Institute of Pediatrics Affiliated Children's Hospital, Beijing, China
| | - Qian Jiang
- Department of Medical Genetics, Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China
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11
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Banning A, Schiff M, Tikkanen R. Amlexanox provides a potential therapy for nonsense mutations in the lysosomal storage disorder Aspartylglucosaminuria. Biochim Biophys Acta Mol Basis Dis 2017; 1864:668-675. [PMID: 29247835 DOI: 10.1016/j.bbadis.2017.12.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/17/2017] [Accepted: 12/11/2017] [Indexed: 10/18/2022]
Abstract
Aspartylglucosaminuria (AGU) is a lysosomal storage disorder caused by mutations in the gene for aspartylglucosaminidase (AGA). This enzyme participates in glycoprotein degradation in lysosomes. AGU results in progressive mental retardation, and no curative therapy is currently available. We have here characterized the consequences of AGA gene mutations in a compound heterozygous patient who exhibits a missense mutation producing a Ser72Pro substitution in one allele, and a nonsense mutation Trp168X in the other. Ser72 is not a catalytic residue, but is required for the stabilization of the active site conformation. Thus, Ser72Pro exchange impairs the autocatalytic activation of the AGA precursor, and results in a considerable reduction of the enzyme activity and in altered AGA precursor processing. Betaine, which can partially rescue the AGA activity in AGU patients carrying certain missense mutations, turned out to be ineffective in the case of Ser72Pro substitution. The Trp168X nonsense allele results in complete lack of AGA polypeptide due to nonsense-mediated decay (NMD) of the mRNA. Amlexanox, which inhibits NMD and causes a translational read-through, facilitated the synthesis of a full-length, functional AGA protein from the nonsense allele. This could be demonstrated as presence of the AGA polypeptide and increased enzyme activity upon Amlexanox treatment. Furthermore, in the Ser72Pro/Trp168X expressing cells, Amlexanox induced a synergistic increase in AGA activity and polypeptide processing due to enhanced processing of the Ser72Pro polypeptide. Our data show for the first time that Amlexanox might provide a valid therapy for AGU.
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Affiliation(s)
- Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany
| | - Manuel Schiff
- AP-HP, Robert Debré Hospital, Reference Center for Inherited Metabolic Diseases, University Paris Diderot-Sorbonne Paris Cité, PROTECT, INSERM U1141, Paris, France
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany.
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12
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Optimized approach for the identification of highly efficient correctors of nonsense mutations in human diseases. PLoS One 2017; 12:e0187930. [PMID: 29131862 PMCID: PMC5683606 DOI: 10.1371/journal.pone.0187930] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 10/27/2017] [Indexed: 11/23/2022] Open
Abstract
About 10% of patients with a genetic disease carry a nonsense mutation causing their pathology. A strategy for correcting nonsense mutations is premature termination codon (PTC) readthrough, i.e. incorporation of an amino acid at the PTC position during translation. PTC-readthrough-activating molecules appear as promising therapeutic tools for these patients. Unfortunately, the molecules shown to induce PTC readthrough show low efficacy, probably because the mRNAs carrying a nonsense mutation are scarce, as they are also substrates of the quality control mechanism called nonsense-mediated mRNA decay (NMD). The screening systems previously developed to identify readthrough-promoting molecules used cDNA constructs encoding mRNAs immune to NMD. As the molecules identified were not selected for the ability to correct nonsense mutations on NMD-prone PTC-mRNAs, they could be unsuitable for the context of nonsense-mutation-linked human pathologies. Here, a screening system based on an NMD-prone mRNA is described. It should be suitable for identifying molecules capable of efficiently rescuing the expression of human genes harboring a nonsense mutation. This system should favor the discovery of candidate drugs for treating genetic diseases caused by nonsense mutations. One hit selected with this screening system is presented and validated on cells from three cystic fibrosis patients.
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13
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Bolze F, Mocek S, Zimmermann A, Klingenspor M. Aminoglycosides, but not PTC124 (Ataluren), rescue nonsense mutations in the leptin receptor and in luciferase reporter genes. Sci Rep 2017; 7:1020. [PMID: 28432296 PMCID: PMC5430635 DOI: 10.1038/s41598-017-01093-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/23/2017] [Indexed: 11/09/2022] Open
Abstract
In rare cases, monogenetic obesity is caused by nonsense mutations in genes regulating energy balance. A key factor herein is the leptin receptor. Here, we focus on leptin receptor nonsense variants causing obesity, namely the human W31X, murine Y333X and rat Y763X mutations, and explored their susceptibilities to aminoglycoside and PTC124 mediated translational read-through in vitro. In a luciferase based assay, all mutations - when analysed within the mouse receptor - were prone to aminoglycoside mediated nonsense suppression with the highest susceptibility for W31X, followed by Y763X and Y333X. For the latter, the corresponding rodent models appear valuable for in vivo experiments. When W31X was studied in the human receptor, its superior read-through susceptibility – initially observed in the mouse receptor – was eliminated, likely due to the different nucleotide context surrounding the mutation in the two orthologues. The impact of the surrounding context on the read-through opens the possibility to discover novel sequence elements influencing nonsense suppression. As an alternative to toxic aminoglycosides, PTC124 was indicated as a superior nonsense suppressor but inconsistent data concerning its read-through activity are reported. PTC124 failed to rescue W31X as well as different nonsense mutated luciferase reporters, thus, challenging its ability to induce translational read-through.
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Affiliation(s)
- Florian Bolze
- ZIEL - Institute for Food and Health, Technical University of Munich, Gregor-Mendel-Str. 2, 85354, Freising, Germany.,Chair of Molecular Nutritional Medicine, Technical University of Munich, EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354, Freising, Germany
| | - Sabine Mocek
- ZIEL - Institute for Food and Health, Technical University of Munich, Gregor-Mendel-Str. 2, 85354, Freising, Germany.,Chair of Molecular Nutritional Medicine, Technical University of Munich, EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354, Freising, Germany
| | - Anika Zimmermann
- ZIEL - Institute for Food and Health, Technical University of Munich, Gregor-Mendel-Str. 2, 85354, Freising, Germany.,Chair of Molecular Nutritional Medicine, Technical University of Munich, EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354, Freising, Germany
| | - Martin Klingenspor
- ZIEL - Institute for Food and Health, Technical University of Munich, Gregor-Mendel-Str. 2, 85354, Freising, Germany. .,Chair of Molecular Nutritional Medicine, Technical University of Munich, EKFZ - Else Kröner-Fresenius-Center for Nutritional Medicine, Gregor-Mendel-Str. 2, 85354, Freising, Germany.
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14
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Affiliation(s)
| | - Maria Daniela D'Agostino
- McGill University Department of Human Genetics and McGill University Health Center, Department of Medical Genetics, Montreal, QC, Canada
| | - Nancy Braverman
- McGill University Department of Human Genetics and Pediatrics, and The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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15
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Pibiri I, Lentini L, Tutone M, Melfi R, Pace A, Di Leonardo A. Exploring the readthrough of nonsense mutations by non-acidic Ataluren analogues selected by ligand-based virtual screening. Eur J Med Chem 2016; 122:429-435. [PMID: 27404557 DOI: 10.1016/j.ejmech.2016.06.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/09/2016] [Accepted: 06/27/2016] [Indexed: 10/21/2022]
Abstract
Ataluren, also known as PTC124, is a 5-(fluorophenyl)-1,2,4-oxadiazolyl-benzoic acid suggested to suppress nonsense mutations by readthrough of premature stop codons in the mRNA. Potential interaction of PTC124 with mRNA has been recently studied by molecular dynamics simulations highlighting the importance of H-bonding and stacking π-π interactions. A series of non-acidic analogues of PTC124 were selected from a large database via a ligand-based virtual screening approach. Eight of them were synthesized and tested for their readthrough activity using the Fluc reporter harboring the UGA premature stop codon. The most active compound was further tested for suppression of the UGA nonsense mutation in the bronchial epithelial IB3.1 cell line carrying the W1282X mutation in the CFTR gene.
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Affiliation(s)
- Ivana Pibiri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy
| | - Laura Lentini
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy.
| | - Marco Tutone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy
| | - Raffaella Melfi
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy
| | - Andrea Pace
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy; Istituto EuroMediterraneo di Scienza e Tecnologia (IEMEST), Via Emerico Amari 123, 90139 Palermo, Italy.
| | - Aldo Di Leonardo
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, Viale delle Scienze Ed. 16-17, 90128 Palermo, Italy; Centro di OncoBiologia Sperimentale (COBS), via San Lorenzo Colli, 90145 Palermo, Italy
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16
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Namgoong JH, Bertoni C. Clinical potential of ataluren in the treatment of Duchenne muscular dystrophy. Degener Neurol Neuromuscul Dis 2016; 6:37-48. [PMID: 30050367 PMCID: PMC6053089 DOI: 10.2147/dnnd.s71808] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an autosomal dominant, X-linked neuromuscular disorder caused by mutations in dystrophin, one of the largest genes known to date. Dystrophin gene mutations are generally transmitted from the mother to male offspring and can occur throughout the coding length of the gene. The majority of the methodologies aimed at treating the disorder have focused on restoring a shorter, although partially functional, dystrophin protein. The approach has the potential of converting a severe DMD phenotype into a milder form of the disease known as Becker muscular dystrophy. Others have focused on ameliorating the disease by targeting secondary pathologies such as inflammation or loss of regeneration. Of great potential is the development of strategies that are capable of restoring full-length dystrophin expression due to their ability to produce a normal, fully functional protein. Among these strategies, the use of read-through compounds (RTCs) that could be administered orally represents an ideal option. Gentamicin has been previously tested in clinical trials for DMD with limited or no success, and its use in the clinic has been dismissed due to issues of toxicity and lack of clear benefits to patients. More recently, new RTCs have been identified and tested in animal models for DMD. This review will focus on one of those RTCs known as ataluren that has now completed Phase III clinical studies for DMD and at providing an overview of the different stages that have led to its clinical development for the disease. The impact that this new drug may have on DMD and its future perspectives will also be described, with an emphasis on the importance of further assessing the clinical benefits of this molecule in patients as it becomes available on the market in different countries.
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Affiliation(s)
- John Hyun Namgoong
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA,
| | - Carmen Bertoni
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA,
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17
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Spielberg DR, Clancy JP. Cystic Fibrosis and Its Management Through Established and Emerging Therapies. Annu Rev Genomics Hum Genet 2016; 17:155-75. [PMID: 26905785 DOI: 10.1146/annurev-genom-090314-050024] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cystic fibrosis (CF) is the most common life-shortening autosomal recessive disorder in the Caucasian population and occurs in many other ethnicities worldwide. The daily treatment burden is substantial for CF patients even when they are well, with numerous pharmacologic and physical therapies targeting lung disease requiring the greatest time commitment. CF treatments continue to advance with greater understanding of factors influencing long-term morbidity and mortality. In recent years, in-depth understanding of genetic and protein structure-function relationships has led to the introduction of targeted therapies for patients with specific CF genotypes. With these advances, CF has become a model of personalized or precision medicine. The near future will see greater access to targeted therapies for most patients carrying common mutations, which will mandate individualized bench-to-bedside methodologies for those with rare genotypes.
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Affiliation(s)
- David R Spielberg
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio 45229; ,
| | - John P Clancy
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati, Cincinnati, Ohio 45229; ,
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18
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Caspi M, Firsow A, Rajkumar R, Skalka N, Moshkovitz I, Munitz A, Pasmanik-Chor M, Greif H, Megido D, Kariv R, Rosenberg DW, Rosin-Arbesfeld R. A flow cytometry-based reporter assay identifies macrolide antibiotics as nonsense mutation read-through agents. J Mol Med (Berl) 2015; 94:469-82. [PMID: 26620677 DOI: 10.1007/s00109-015-1364-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/24/2015] [Accepted: 11/03/2015] [Indexed: 01/01/2023]
Abstract
UNLABELLED A large number of human diseases are caused by nonsense mutations. These mutations result in premature protein termination and the expression of truncated, usually nonfunctional products. A promising therapeutic strategy for patients suffering from premature termination codon (PTC)-mediated disorders is to suppress the nonsense mutation and restore the expression of the affected protein. Such a suppression approach using specific antibiotics and other read-through promoting agents has been shown to suppress PTCs and restore the production of several important proteins. Here, we report the establishment of a novel, rapid, and very efficient method for screening stop-codon read-through agents. We also show that, in both mammalian cells and in a transgenic mouse model, distinct members of the macrolide antibiotic family can induce read-through of disease-causing stop codons leading to re-expression of several key proteins and to reduced disease phenotypes. Taken together, our results may help in the identification and characterization of well-needed customized pharmaceutical PTC suppression agents. KEY MESSAGES Establishment of a flow cytometry-based reporter assay to identify nonsense mutation read-through agents. Macrolide antibiotics can induce read-through of disease-causing stop codons. Macrolide-induced protein restoration can alleviate disease-like phenotypes.
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Affiliation(s)
- Michal Caspi
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Anastasia Firsow
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Raja Rajkumar
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Nir Skalka
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Itay Moshkovitz
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Ariel Munitz
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, G.S.W. Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
| | | | | | - Revital Kariv
- Department of Gastroenterology, Tel Aviv Sourasky Medical Center, Tel Aviv, 64239, Israel
| | - Daniel W Rosenberg
- Center for Molecular Medicine, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, 69978, Tel Aviv, Israel.
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19
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Baes M, Van Veldhoven PP. Hepatic dysfunction in peroxisomal disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:956-70. [PMID: 26453805 DOI: 10.1016/j.bbamcr.2015.09.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022]
Abstract
The peroxisomal compartment in hepatocytes hosts several essential metabolic conversions. These are defective in peroxisomal disorders that are either caused by failure to import the enzymes in the organelle or by mutations in the enzymes or in transporters needed to transfer the substrates across the peroxisomal membrane. Hepatic pathology is one of the cardinal features in disorders of peroxisome biogenesis and peroxisomal β-oxidation although it only rarely determines the clinical fate. In mouse models of these diseases liver pathologies also occur, although these are not always concordant with the human phenotype which might be due to differences in diet, expression of enzymes and backup mechanisms. Besides the morphological changes, we overview the impact of peroxisome malfunction on other cellular compartments including mitochondria and the ER. We further focus on the metabolic pathways that are affected such as bile acid formation, and dicarboxylic acid and branched chain fatty acid degradation. It appears that the association between deregulated metabolites and pathological events remains unclear.
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Affiliation(s)
- Myriam Baes
- Laboratory for Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, B-3000 Leuven, Belgium.
| | - Paul P Van Veldhoven
- Laboratory for Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium.
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20
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Wang XM, Yik WY, Zhang P, Lu W, Huang N, Kim BR, Shibata D, Zitting M, Chow RH, Moser AB, Steinberg SJ, Hacia JG. Induced pluripotent stem cell models of Zellweger spectrum disorder show impaired peroxisome assembly and cell type-specific lipid abnormalities. Stem Cell Res Ther 2015; 6:158. [PMID: 26319495 PMCID: PMC4553005 DOI: 10.1186/s13287-015-0149-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/26/2015] [Accepted: 08/07/2015] [Indexed: 01/08/2023] Open
Abstract
Introduction Zellweger spectrum disorder (PBD-ZSD) is a disease continuum caused by mutations in a subset of PEX genes required for normal peroxisome assembly and function. They highlight the importance of peroxisomes in the development and functions of the central nervous system, liver, and other organs. To date, the underlying bases for the cell-type specificity of disease are not fully elucidated. Methods Primary skin fibroblasts from seven PBD-ZSD patients with biallelic PEX1, PEX10, PEX12, or PEX26 mutations and three healthy donors were transduced with retroviral vectors expressing Yamanaka reprogramming factors. Candidate induced pluripotent stem cells (iPSCs) were subject to global gene expression, DNA methylation, copy number variation, genotyping, in vitro differentiation and teratoma formation assays. Confirmed iPSCs were differentiated into neural progenitor cells (NPCs), neurons, oligodendrocyte precursor cells (OPCs), and hepatocyte-like cell cultures with peroxisome assembly evaluated by microscopy. Saturated very long chain fatty acid (sVLCFA) and plasmalogen levels were determined in primary fibroblasts and their derivatives. Results iPSCs were derived from seven PBD-ZSD patient-derived fibroblasts with mild to severe peroxisome assembly defects. Although patient and control skin fibroblasts had similar gene expression profiles, genes related to mitochondrial functions and organelle cross-talk were differentially expressed among corresponding iPSCs. Mitochondrial DNA levels were consistent among patient and control fibroblasts, but varied among all iPSCs. Relative to matching controls, sVLCFA levels were elevated in patient-derived fibroblasts, reduced in patient-derived iPSCs, and not significantly different in patient-derived NPCs. All cell types derived from donors with biallelic null mutations in a PEX gene showed plasmalogen deficiencies. Reporter gene assays compatible with high content screening (HCS) indicated patient-derived OPC and hepatocyte-like cell cultures had impaired peroxisome assembly. Conclusions Normal peroxisome activity levels are not required for cellular reprogramming of skin fibroblasts. Patient iPSC gene expression profiles were consistent with hypotheses highlighting the role of altered mitochondrial activities and organelle cross-talk in PBD-ZSD pathogenesis. sVLCFA abnormalities dramatically differed among patient cell types, similar to observations made in iPSC models of X-linked adrenoleukodystrophy. We propose that iPSCs could assist investigations into the cell type-specificity of peroxisomal activities, toxicology studies, and in HCS for targeted therapies for peroxisome-related disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13287-015-0149-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiao-Ming Wang
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Wing Yan Yik
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Peilin Zhang
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Wange Lu
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Ning Huang
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Bo Ram Kim
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
| | - Darryl Shibata
- Department of Pathology, University of Southern California, Los Angeles, California, USA.
| | - Madison Zitting
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, California, USA.
| | - Robert H Chow
- Department of Physiology and Biophysics, University of Southern California, Los Angeles, California, USA.
| | - Ann B Moser
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, USA.
| | - Steven J Steinberg
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, USA.
| | - Joseph G Hacia
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
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21
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Farr RL, Lismont C, Terlecky SR, Fransen M. Peroxisome biogenesis in mammalian cells: The impact of genes and environment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1049-60. [PMID: 26305119 DOI: 10.1016/j.bbamcr.2015.08.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 01/16/2023]
Abstract
The initiation and progression of many human diseases are mediated by a complex interplay of genetic, epigenetic, and environmental factors. As all diseases begin with an imbalance at the cellular level, it is essential to understand how various types of molecular aberrations, metabolic changes, and environmental stressors function as switching points in essential communication networks. In recent years, peroxisomes have emerged as important intracellular hubs for redox-, lipid-, inflammatory-, and nucleic acid-mediated signaling pathways. In this review, we focus on how nature and nurture modulate peroxisome biogenesis and function in mammalian cells. First, we review emerging evidence that changes in peroxisome activity can be linked to the epigenetic regulation of cell function. Next, we outline how defects in peroxisome biogenesis may directly impact cellular pathways involved in the development of disease. In addition, we discuss how changes in the cellular microenvironment can modulate peroxisome biogenesis and function. Finally, given the importance of peroxisome function in multiple aspects of health, disease, and aging, we highlight the need for more research in this still understudied field.
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Affiliation(s)
- Rebecca L Farr
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Herestraat 49 box 601, B-3000 Leuven, Belgium; Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201, USA
| | - Celien Lismont
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Herestraat 49 box 601, B-3000 Leuven, Belgium
| | - Stanley R Terlecky
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., Detroit, MI 48201, USA
| | - Marc Fransen
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Herestraat 49 box 601, B-3000 Leuven, Belgium.
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22
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Evaluation of Aminoglycoside and Non-Aminoglycoside Compounds for Stop-Codon Readthrough Therapy in Four Lysosomal Storage Diseases. PLoS One 2015; 10:e0135873. [PMID: 26287674 PMCID: PMC4545610 DOI: 10.1371/journal.pone.0135873] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 07/27/2015] [Indexed: 11/21/2022] Open
Abstract
Nonsense mutations are quite prevalent in inherited diseases. Readthrough drugs could provide a therapeutic option for any disease caused by this type of mutation. Geneticin (G418) and gentamicin were among the first to be described. Novel compounds have been generated, but only a few have shown improved results. PTC124 is the only compound to have reached clinical trials. Here we first investigated the readthrough effects of gentamicin on fibroblasts from one patient with Sanfilippo B, one with Sanfilippo C, and one with Maroteaux-Lamy. We found that ARSB activity (Maroteaux-Lamy case) resulted in an increase of 2–3 folds and that the amount of this enzyme within the lysosomes was also increased, after treatment. Since the other two cases (Sanfilippo B and Sanfilippo C) did not respond to gentamicin, the treatments were extended with the use of geneticin and five non-aminoglycoside (PTC124, RTC13, RTC14, BZ6 and BZ16) readthrough compounds (RTCs). No recovery was observed at the enzyme activity level. However, mRNA recovery was observed in both cases, nearly a two-fold increase for Sanfilippo B fibroblasts with G418 and around 1.5 fold increase for Sanfilippo C cells with RTC14 and PTC124. Afterwards, some of the products were assessed through in vitro analyses for seven mutations in genes responsible for those diseases and, also, for Niemann-Pick A/B. Using the coupled transcription/translation system (TNT), the best results were obtained for SMPD1 mutations with G418, reaching a 35% recovery at 0.25 μg/ml, for the p.W168X mutation. The use of COS cells transfected with mutant cDNAs gave positive results for most of the mutations with some of the drugs, although to a different extent. The higher enzyme activity recovery, of around two-fold increase, was found for gentamicin on the ARSB p.W146X mutation. Our results are promising and consistent with those of other groups. Further studies of novel compounds are necessary to find those with more consistent efficacy and fewer toxic effects.
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23
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Bhuvanagiri M, Lewis J, Putzker K, Becker JP, Leicht S, Krijgsveld J, Batra R, Turnwald B, Jovanovic B, Hauer C, Sieber J, Hentze MW, Kulozik AE. 5-azacytidine inhibits nonsense-mediated decay in a MYC-dependent fashion. EMBO Mol Med 2015; 6:1593-609. [PMID: 25319547 PMCID: PMC4287977 DOI: 10.15252/emmm.201404461] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nonsense-mediated RNA decay (NMD) is an RNA-based quality control mechanism that eliminates
transcripts bearing premature translation termination codons (PTC). Approximately, one-third of all
inherited disorders and some forms of cancer are caused by nonsense or frame shift mutations that
introduce PTCs, and NMD can modulate the clinical phenotype of these diseases. 5-azacytidine is an
analogue of the naturally occurring pyrimidine nucleoside cytidine, which is approved for the
treatment of myelodysplastic syndrome and myeloid leukemia. Here, we reveal that 5-azacytidine
inhibits NMD in a dose-dependent fashion specifically upregulating the expression of both
PTC-containing mutant and cellular NMD targets. Moreover, this activity of 5-azacytidine depends on
the induction of MYC expression, thus providing a link between the effect of this drug and one of
the key cellular pathways that are known to affect NMD activity. Furthermore, the effective
concentration of 5-azacytidine in cells corresponds to drug levels used in patients, qualifying
5-azacytidine as a candidate drug that could potentially be repurposed for the treatment of
Mendelian and acquired genetic diseases that are caused by PTC mutations.
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Affiliation(s)
- Madhuri Bhuvanagiri
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany European Molecular Biology Laboratory, Heidelberg, Germany
| | - Joe Lewis
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Jonas P Becker
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
| | - Stefan Leicht
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Richa Batra
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Brad Turnwald
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
| | - Bogdan Jovanovic
- Centre for Molecular Biology of the University of HeidelbergUniversity of Heidelberg, Heidelberg, Germany
| | - Christian Hauer
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jana Sieber
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
| | - Matthias W Hentze
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andreas E Kulozik
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, University of Heidelberg, Heidelberg, Germany Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany
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Enhancement of premature stop codon readthrough in the CFTR gene by Ataluren (PTC124) derivatives. Eur J Med Chem 2015; 101:236-44. [PMID: 26142488 DOI: 10.1016/j.ejmech.2015.06.038] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/14/2015] [Accepted: 06/19/2015] [Indexed: 12/31/2022]
Abstract
Premature stop codons are the result of nonsense mutations occurring within the coding sequence of a gene. These mutations lead to the synthesis of a truncated protein and are responsible for several genetic diseases. A potential pharmacological approach to treat these diseases is to promote the translational readthrough of premature stop codons by small molecules aiming to restore the full-length protein. The compound PTC124 (Ataluren) was reported to promote the readthrough of the premature UGA stop codon, although its activity was questioned. The potential interaction of PTC124 with mutated mRNA was recently suggested by molecular dynamics (MD) studies highlighting the importance of H-bonding and stacking π-π interactions. To improve the readthrough activity we changed the fluorine number and position in the PTC124 fluoroaryl moiety. The readthrough ability of these PTC124 derivatives was tested in human cells harboring reporter plasmids with premature stop codons in H2BGFP and FLuc genes as well as in cystic fibrosis (CF) IB3.1 cells with a nonsense mutation. Maintaining low toxicity, three of these molecules showed higher efficacy than PTC124 in the readthrough of the UGA premature stop codon and in recovering the expression of the CFTR protein in IB3.1 cells from cystic fibrosis patient. Molecular dynamics simulations performed with mutated CFTR mRNA fragments and active or inactive derivatives are in agreement with the suggested interaction of PTC124 with mRNA.
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Wang X, Gregory-Evans CY. Nonsense suppression therapies in ocular genetic diseases. Cell Mol Life Sci 2015; 72:1931-8. [PMID: 25651836 PMCID: PMC11113309 DOI: 10.1007/s00018-015-1843-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/23/2014] [Accepted: 01/23/2015] [Indexed: 12/24/2022]
Abstract
Premature termination codons (PTCs) are caused by nonsense mutations and this leads to either degradation of the mutant mRNA template by nonsense-mediated decay (NMD) or the production of a non-functional, truncated polypeptide. PTCs contribute significantly to inherited human diseases including ocular disorders. Nonsense suppression therapy allows readthrough of PTCs, thereby rescuing the production of a full-length functional protein. In this review, we highlight the mechanisms that are involved in discriminating normal translation termination from premature termination codons; the current understanding of nonsense-mediated mRNA decay models (NMD); the association and crosstalk between PTC and the underlying dynamic NMD process; and the suppression therapies that have been employed in nonsense-medicated ocular disease models. Defining the mechanistic complexity of PTC and NMD will be important to improve treatments of the numerous genetic disorders caused by PTC mutations.
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Affiliation(s)
- Xia Wang
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, V5Z 3N9, Canada,
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Nonsense-mediated decay in genetic disease: friend or foe? MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 762:52-64. [PMID: 25485595 DOI: 10.1016/j.mrrev.2014.05.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 05/02/2014] [Accepted: 05/03/2014] [Indexed: 12/11/2022]
Abstract
Eukaryotic cells utilize various RNA quality control mechanisms to ensure high fidelity of gene expression, thus protecting against the accumulation of nonfunctional RNA and the subsequent production of abnormal peptides. Messenger RNAs (mRNAs) are largely responsible for protein production, and mRNA quality control is particularly important for protecting the cell against the downstream effects of genetic mutations. Nonsense-mediated decay (NMD) is an evolutionarily conserved mRNA quality control system in all eukaryotes that degrades transcripts containing premature termination codons (PTCs). By degrading these aberrant transcripts, NMD acts to prevent the production of truncated proteins that could otherwise harm the cell through various insults, such as dominant negative effects or the ER stress response. Although NMD functions to protect the cell against the deleterious effects of aberrant mRNA, there is a growing body of evidence that mutation-, codon-, gene-, cell-, and tissue-specific differences in NMD efficiency can alter the underlying pathology of genetic disease. In addition, the protective role that NMD plays in genetic disease can undermine current therapeutic strategies aimed at increasing the production of full-length functional protein from genes harboring nonsense mutations. Here, we review the normal function of this RNA surveillance pathway and how it is regulated, provide current evidence for the role that it plays in modulating genetic disease phenotypes, and how NMD can be used as a therapeutic target.
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Abstract
Nonsense suppression therapy encompasses approaches aimed at suppressing translation termination at in-frame premature termination codons (PTCs, also known as nonsense mutations) to restore deficient protein function. In this review, we examine the current status of PTC suppression as a therapy for genetic diseases caused by nonsense mutations. We discuss what is currently known about the mechanism of PTC suppression as well as therapeutic approaches under development to suppress PTCs. The approaches considered include readthrough drugs, suppressor tRNAs, PTC pseudouridylation, and inhibition of nonsense-mediated mRNA decay. We also discuss the barriers that currently limit the clinical application of nonsense suppression therapy and suggest how some of these difficulties may be overcome. Finally, we consider how PTC suppression may play a role in the clinical treatment of genetic diseases caused by nonsense mutations.
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Affiliation(s)
- Kim M Keeling
- Department of Microbiology and Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294; , , ,
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Yu H, Liu X, Huang J, Zhang Y, Hu R, Pu J. Comparison of read-through effects of aminoglycosides and PTC124 on rescuing nonsense mutations of HERG gene associated with long QT syndrome. Int J Mol Med 2013; 33:729-35. [PMID: 24366185 DOI: 10.3892/ijmm.2013.1601] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/10/2013] [Indexed: 11/06/2022] Open
Abstract
Aminoglycosides promote the readthrough of premature stop codons introduced by nonsense mutations to produce full-length proteins in genetic disease models. The read-through effects of different aminoglycosides and PTC124 on HERG gene have yet to be adequately elucidated. The wild-type (WT) or mutant genes were transiently transfected in HEK293 cells. The read-through effect was examined by adding drugs into culture medium for 24 h. Western blot analysis and patch clamping were performed to evaluate the expression and function of the genes. The mRNA levels were determined using qPCR. The results showed that G418 and PTC124 significantly increased the protein expression of R1014X mutant in a dose-dependent manner and produced a full-length protein. The maximal protein levels after G418, gentamicin or PTC124 treatment were 39.1±2.4, 18.6±0.3 or 10.3±1.0%, respectively, of the WT level. Tobramycin did not exhibit a read-through effect. The mRNA levels, however, did not differ between WT and mutant gene. The tail current densities of R1014X channels at 40 mV were 22.57±2.26 pA/pF for G418, 16.21±1.49 pA/pF for gentamicin and 9.62±0.73 pA/pF for PTC124. The leftward shift of the activation curve was corrected only by G418 and gentamicin. The read-through effects of W927X, R863X and E698X revealed that as the mutation site approached the N-terminal, the rescue efficiency was decreased. The above results suggest that aminoglycosides and PTC124 induced different effects on rescue nonsense mutations of the HERG gene. The mutation site was a significant factor in determining the pharmacological rescue efficiency.
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Affiliation(s)
- Haiyun Yu
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Xiaoyan Liu
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Jian Huang
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Yinhui Zhang
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Roumu Hu
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Jielin Pu
- State Key Laboratory of Cardiovascular Disease, Physiology and Pathophysiology Laboratory, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
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Ho G, Reichardt J, Christodoulou J. In vitro read-through of phenylalanine hydroxylase (PAH) nonsense mutations using aminoglycosides: a potential therapy for phenylketonuria. J Inherit Metab Dis 2013; 36:955-9. [PMID: 23532445 DOI: 10.1007/s10545-013-9602-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/07/2013] [Accepted: 03/04/2013] [Indexed: 01/27/2023]
Abstract
Phenylketonuria (PKU, OMIM 261600) is an autosomal recessive inborn error of phenylalanine metabolism, predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene. Approximately 10% of patients carry a nonsense mutation, which results in an inactive or unstable truncated protein. In some genetic disorders, including cystic fibrosis and Duchenne muscular dystrophy, restoration of full-length protein has been achieved by aminoglycoside antibiotics, such as gentamicin and G-418 (Geneticin). More recently, nonsense read-through has been induced at greater rates using a non-aminoglycoside drug, PTC124 (Ataluren), which has the advantage of being non-toxic in contrast to the antibiotics. The efficacy of read-through induced by three compounds, aminoglycosides G418 and gentamicin, and PTC124 were evaluated for four nonsense mutations of PAH in an in vitro expression system in two mammalian cell lines (COS-7 and HEK293). The production of full-length PAH was investigated using western blotting and the functionality confirmed by enzyme activity. Gentamicin and G-418 induced read-through of nonsense PAH mutations in HEK293 cells. The read-through product partially restored enzymatic activity, which was significantly less than that of wild-type, but comparable to a missense mutation of PAH associated with less severe forms of PKU. Treatment with PTC124 up to 100 μM did not result in full-length PAH polypeptide. Nonsense read-through drugs are a potential form of treatment for PKU, although the high dosage of aminoglycosides used is not appropriate in a clinical setting. In vitro studies with new non-toxic read-through agents as well as in vivo studies would also be essential to determine the extent of read-through required to restore normal phenylalanine levels.
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Affiliation(s)
- Gladys Ho
- Genetic Metabolic Disorders Research Unit, Children's Hospital at Westmead, Sydney, Australia
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A lack of premature termination codon read-through efficacy of PTC124 (Ataluren) in a diverse array of reporter assays. PLoS Biol 2013; 11:e1001593. [PMID: 23824517 PMCID: PMC3692445 DOI: 10.1371/journal.pbio.1001593] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 05/15/2013] [Indexed: 01/23/2023] Open
Abstract
Numerous nonsense mutation reporter assays fail to reveal read-through activity for the drug PTC124. The drug molecule PTC124 (Ataluren) has been described as a read-through agent, capable of suppressing premature termination codons (PTCs) and restoring functional protein production from genes disrupted by nonsense mutations. Following the discovery of PTC124 there was some controversy regarding its mechanism of action with two reports attributing its activity to an off-target effect on the Firefly luciferase (FLuc) reporter used in the development of the molecule. Despite questions remaining as to its mechanism of action, development of PTC124 continued into the clinic and it is being actively pursued as a potential nonsense mutation therapy. To thoroughly test the ability of PTC124 to read through nonsense mutations, we conducted a detailed assessment comparing the efficacy of PTC124 with the classical aminoglycoside antibiotic read-through agent geneticin (G418) across a diverse range of in vitro reporter assays. We can confirm the off-target FLuc activity of PTC124 but found that, while G418 exhibits varying activity in every read-through assay, there is no evidence of activity for PTC124. Ten percent of all single-gene hereditary diseases are caused by nonsense mutations. These are alterations in the DNA sequence of a protein-coding gene that cause the ribosome to prematurely finish translating the gene transcript before a full-length, active protein can be produced. In 2007 a drug was developed called PTC124 (latterly known as Ataluren), which was reported to help the ribosome skip over the premature stop, restore production of functional protein, and thereby potentially treat these genetic diseases. In 2009, however, questions were raised about the initial discovery of this drug; PTC124 was shown to interfere with the assay used in its discovery in a way that might be mistaken for genuine activity. As doubts regarding PTC124's efficacy remain unresolved, here we conducted a thorough and systematic investigation of the proposed mechanism of action of PTC124 in a wide array of cell-based assays. We found no evidence of such translational read-through activity for PTC124, suggesting that its development may indeed have been a consequence of the choice of assay used in the drug discovery process.
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Braverman NE, D'Agostino MD, MacLean GE. Peroxisome biogenesis disorders: Biological, clinical and pathophysiological perspectives. ACTA ACUST UNITED AC 2013; 17:187-96. [DOI: 10.1002/ddrr.1113] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/17/2012] [Indexed: 01/08/2023]
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Abstract
The interplay of translation and mRNA turnover has helped unveil how the regulation of gene expression is a continuum in which events that occur during the birth of a transcript in the nucleus can have profound effects on subsequent steps in the cytoplasm. Exemplifying this continuum is nonsense-mediated mRNA decay (NMD), the process wherein a premature stop codon affects both translation and mRNA decay. Studies of NMD helped lead us to the therapeutic concept of treating a subset of patients suffering from multiple genetic disorders due to nonsense mutations with a single small-molecule drug that modulates the translation termination process at a premature nonsense codon. Here we review both translation termination and NMD, and our subsequent efforts over the past 15 years that led to the identification, characterization, and clinical testing of ataluren, a new therapeutic with the potential to treat a broad range of genetic disorders due to nonsense mutations.
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Affiliation(s)
- Stuart W Peltz
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA.
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Pérez B, Rodríguez-Pombo P, Ugarte M, Desviat L. Readthrough strategies for therapeutic suppression of nonsense mutations in inherited metabolic disease. Mol Syndromol 2012; 3:230-6. [PMID: 23293581 PMCID: PMC3531923 DOI: 10.1159/000343086] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Inherited metabolic diseases (IMDs) belong to the group of rare diseases due to their low individual prevalence. Most of them are inherited in autosomal recessive fashion and represent good candidates for novel therapeutical strategies aimed at recovering partial enzyme function as they lack an effective treatment, and small levels of enzymatic activity have been shown to be associated with improved outcome and milder phenotypes. Recently, a novel therapeutic approach for genetic diseases has emerged, based on the ability of aminoglycosides and other compounds in allowing translation to proceed through a premature termination codon introduced by a nonsense mutation, which frequently constitute a significant fraction of the mutant alleles in a population. In this review we summarize the essentials of what is known as suppression therapy, the different compounds that have been identified by high-throughput screens or developed using a medicinal chemistry approach and the preclinical and clinical trials that are being conducted in general and in the field of IMDs in particular. Several IMDs have shown to be good models for evaluating readthrough compounds using patients' cells carrying nonsense mutations, monitoring for an increase in functional recovery and/or enzyme activity. Overall, the positive results obtained indicate the feasibility of the approach for different diseases and although the levels of protein function reached are low, they may be enough to alleviate the consequences of the pathology. Nonsense suppression thus represents a potential therapy or supplementary treatment for a number of IMD patients encouraging further clinical trials with readthrough drugs with improved functionality and low toxicity.
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Affiliation(s)
| | | | | | - L.R. Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, y Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), y Instituto de Investigación Hospital Universitario La Paz (IDIPaz), Madrid, España
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Gonzalez-Hilarion S, Beghyn T, Jia J, Debreuck N, Berte G, Mamchaoui K, Mouly V, Gruenert DC, Déprez B, Lejeune F. Rescue of nonsense mutations by amlexanox in human cells. Orphanet J Rare Dis 2012; 7:58. [PMID: 22938201 PMCID: PMC3562214 DOI: 10.1186/1750-1172-7-58] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 08/18/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nonsense mutations are at the origin of many cancers and inherited genetic diseases. The consequence of nonsense mutations is often the absence of mutant gene expression due to the activation of an mRNA surveillance mechanism called nonsense-mediated mRNA decay (NMD). Strategies to rescue the expression of nonsense-containing mRNAs have been developed such as NMD inhibition or nonsense mutation readthrough. METHODS Using a dedicated screening system, we sought molecules capable to block NMD. Additionally, 3 cell lines derived from patient cells and harboring a nonsense mutation were used to study the effect of the selected molecule on the level of nonsense-containing mRNAs and the synthesis of proteins from these mutant mRNAs. RESULTS We demonstrate here that amlexanox, a drug used for decades, not only induces an increase in nonsense-containing mRNAs amount in treated cells, but also leads to the synthesis of the full-length protein in an efficient manner. We also demonstrated that these full length proteins are functional. CONCLUSIONS As a result of this dual activity, amlexanox may be useful as a therapeutic approach for diseases caused by nonsense mutations.
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Levesque S, Morin C, Guay SP, Villeneuve J, Marquis P, Yik WY, Jiralerspong S, Bouchard L, Steinberg S, Hacia JG, Dewar K, Braverman NE. A founder mutation in the PEX6 gene is responsible for increased incidence of Zellweger syndrome in a French Canadian population. BMC MEDICAL GENETICS 2012; 13:72. [PMID: 22894767 PMCID: PMC3483250 DOI: 10.1186/1471-2350-13-72] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Accepted: 08/08/2012] [Indexed: 12/16/2022]
Abstract
Background Zellweger syndrome (ZS) is a peroxisome biogenesis disorder due to mutations in any one of 13 PEX genes. Increased incidence of ZS has been suspected in French-Canadians of the Saguenay-Lac-St-Jean region (SLSJ) of Quebec, but this remains unsolved. Methods We identified 5 ZS patients from SLSJ diagnosed by peroxisome dysfunction between 1990–2010 and sequenced all coding exons of known PEX genes in one patient using Next Generation Sequencing (NGS) for diagnostic confirmation. Results A homozygous mutation (c.802_815del, p.[Val207_Gln294del, Val76_Gln294del]) in PEX6 was identified and then shown in 4 other patients. Parental heterozygosity was confirmed in all. Incidence of ZS was estimated to 1 in 12,191 live births, with a carrier frequency of 1 in 55. In addition, we present data suggesting that this mutation abolishes a SF2/ASF splice enhancer binding site, resulting in the use of two alternative cryptic donor splice sites and predicted to encode an internally deleted in-frame protein. Conclusion We report increased incidence of ZS in French-Canadians of SLSJ caused by a PEX6 founder mutation. To our knowledge, this is the highest reported incidence of ZS worldwide. These findings have implications for carrier screening and support the utility of NGS for molecular confirmation of peroxisomal disorders.
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Lee HLR, Dougherty JP. Pharmaceutical therapies to recode nonsense mutations in inherited diseases. Pharmacol Ther 2012; 136:227-66. [PMID: 22820013 DOI: 10.1016/j.pharmthera.2012.07.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2012] [Indexed: 12/21/2022]
Abstract
Nonsense codons, generated from nonsense mutations or frameshifts, contribute significantly to the spectrum of inherited human diseases such as cystic fibrosis, Duchenne muscular dystrophy, hemophilia, spinal muscular atrophy, and many forms of cancer. The presence of a mutant nonsense codon results in premature termination to preclude the synthesis of a full-length protein and leads to aberrations in gene expression. Suppression therapy to recode a premature termination codon with an amino acid allowing readthrough to rescue the production of a full-length protein presents a promising strategy for treatment of patients suffering from debilitating nonsense-mediated disorders. Suppression therapy using aminoglycosides to promote readthrough in vitro have been known since the sixties. Recent progress in the field of recoding via pharmaceuticals has led to the continuous discovery and development of several pharmacological agents with nonsense suppression activities. Here, we review the mechanisms that are involved in discriminating normal versus premature termination codons, the factors involved in readthrough efficiency, the epidemiology of several well-known nonsense-mediated diseases, and the various pharmacological agents (aminoglycoside and non-aminoglycoside compounds) that are currently being employed in nonsense suppression therapy studies. We also discuss how these therapeutic agents can be used to regulate gene expression for gene therapy applications.
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Affiliation(s)
- Hui-Ling Rose Lee
- Department of Molecular Genetics, Microbiology, and Immunology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ, USA
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Dinman JD. Control of gene expression by translational recoding. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012; 86:129-49. [PMID: 22243583 PMCID: PMC7149833 DOI: 10.1016/b978-0-12-386497-0.00004-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Like all rules, even the genetic code has exceptions: these are generically classified as “translational recoding.” Almost every conceivable mode of recoding has been documented, including signals that redefine translational reading frame and codon assignation. While first described in viruses, it is becoming clear that sequences that program elongating ribosomes to shift translational reading frame are widely used by organisms in all domains of life, thus expanding both the coding capacity of genomes and the modes through which gene expression can be regulated at the posttranscriptional level. Instances of programmed ribosomal frameshifting and stop codon reassignment are opening up new avenues for treatment of numerous inborn errors of metabolism. The implications of these findings on human health are only beginning to emerge.
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Affiliation(s)
- Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
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Abstract
PURPOSE OF REVIEW Disease states characterized by abnormal cellular function or proliferation frequently reflect aberrant genetic information. By revealing disease-specific DNA mutations, we gain insight into normal physiology, pathophysiology, potential therapeutic targets and are better equipped to evaluate an individual's disease risks. This review examines recent advances in our understanding of the genetic basis of adrenal cortical disease. RECENT FINDINGS Important advances made in the past year have included identification of KCNJ5 potassium channel mutations in the pathogenesis of both aldosterone-producing adenomas and familial hyperaldosteronism type III; characterization of phosphodiesterase 11A as a modifier of phenotype in Carney complex caused by protein kinase, cAMP-dependent, regulatory subunit, type-I mutations; the finding of 11β-hydroxysteroid dehydrogenase type I mutations as a novel mechanism for cortisone reductase deficiency; and demonstration of potential mortality benefit in pursuing comprehensive presymptomatic screening for patients with Li-Fraumeni syndrome, including possible reduction in risks associated with adrenocortical carcinoma. SUMMARY This research review provides a framework for the endocrinologist to maintain an up-to-date understanding of adrenal cortical disease genetics.
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Affiliation(s)
- Adi Bar-Lev
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Molecular basis of peroxisomal biogenesis disorders caused by defects in peroxisomal matrix protein import. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1326-36. [PMID: 22617146 DOI: 10.1016/j.bbadis.2012.05.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/26/2012] [Accepted: 05/09/2012] [Indexed: 12/28/2022]
Abstract
Peroxisomal biogenesis disorders (PBDs) represent a spectrum of autosomal recessive metabolic disorders that are collectively characterized by abnormal peroxisome assembly and impaired peroxisomal function. The importance of this ubiquitous organelle for human health is highlighted by the fact that PBDs are multisystemic disorders that often cause death in early infancy. Peroxisomes contribute to central metabolic pathways. Most enzymes in the peroxisomal matrix are linked to lipid metabolism and detoxification of reactive oxygen species. Proper assembly of peroxisomes and thus also import of their enzymes relies on specific peroxisomal biogenesis factors, so called peroxins with PEX being the gene acronym. To date, 13 PEX genes are known to cause PBDs when mutated. Studies of the cellular and molecular defects in cells derived from PBD patients have significantly contributed to the understanding of the functional role of the corresponding peroxins in peroxisome assembly. In this review, we discuss recent data derived from both human cell culture as well as model organisms like yeasts and present an overview on the molecular mechanism underlying peroxisomal biogenesis disorders with emphasis on disorders caused by defects in the peroxisomal matrix protein import machinery.
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Sánchez-Alcudia R, Pérez B, Ugarte M, Desviat LR. Feasibility of nonsense mutation readthrough as a novel therapeutical approach in propionic acidemia. Hum Mutat 2012; 33:973-80. [PMID: 22334403 DOI: 10.1002/humu.22047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 01/26/2012] [Indexed: 12/13/2022]
Abstract
Aminoglycosides and other compounds can promote premature termination codon (PTC) readthrough constituting a potential therapy for patients with nonsense mutations. In a cohort of 190 propionic acidemia (PA) patients, we have identified 12 different nonsense mutations, six of them novel, accounting for 10% of the mutant alleles. Using an in vitro system, we establish the proof-of-principle that nonsense mutations in the PCCA and PCCB genes encoding both subunits of the propionyl-CoA carboxylase (PCC) enzyme can be partially suppressed by aminoglycosides, with different efficiencies depending on the sequence context. To correct the metabolic defect, the amino acid incorporated at the PTC should support protein function, and this has been evaluated in silico and by in vitro expression analysis of the predicted missense changes, most of which retain partial activity, confirming the feasibility of the approach. In patients' fibroblasts cultured with readthrough drugs, we observe a fourfold to 50-fold increase in the PCC activity, reaching up to 10-15% level of treated control cells. The ability to partially correct nonsense PCCA and PCCB alleles represents a potential therapy or supplementary treatment for a number of propionic acidemia (PA) patients, encouraging further clinical trials with readthrough drugs without toxic effects such as PTC124 or other newly developed compounds. Hum Mutat 33:973-980, 2012. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Rocío Sánchez-Alcudia
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), IDIPaz, Madrid, Spain
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Readthrough of long-QT syndrome type 1 nonsense mutations rescues function but alters the biophysical properties of the channel. Biochem J 2012; 443:635-42. [DOI: 10.1042/bj20111912] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The nonsense mutations R518X-KCNQ1 and Q530X-KCNQ1 cause LQT1 (long-QT syndrome type 1) and result in a complete loss of IKs channel function. In the present study we attempted to rescue the function of these mutants, in HEK (human embryonic kidney)-293 cells, by promoting readthrough of their PTCs (premature termination codons) using the pharmacological agents G-418, gentamicin and PTC124. Gentamicin and G-418 acted to promote full-length channel protein expression from R518X at 100 μM and from Q530X at 1 mM. In contrast, PTC124 did not, at any dose tested, induce readthrough of either mutant. G-418 (1 mM) treatment also acted to significantly (P<0.05) increase current density and peak-tail current density, at +80 mV for R518X, but not Q530X, to 58±11% and 82±17% of the wild-type level respectively. However, the biophysical properties of the currents produced from R518X, while similar, were not identical with wild-type as the voltage-dependence of activation was significantly (P<0.05) shifted by +25 mV. Overall, these findings indicate that although functional rescue of LQT1 nonsense mutations is possible, it is dependent on the degree of readthrough achieved and the effect on channel function of the amino acid substituted for the PTC. Such considerations will determine the success of future therapies.
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Keeling KM, Bedwell DM. Suppression of nonsense mutations as a therapeutic approach to treat genetic diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:837-52. [PMID: 21976286 DOI: 10.1002/wrna.95] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Suppression therapy is a treatment strategy for genetic diseases caused by nonsense mutations. This therapeutic approach utilizes pharmacological agents that suppress translation termination at in-frame premature termination codons (PTCs) to restore translation of a full-length, functional polypeptide. The efficiency of various classes of compounds to suppress PTCs in mammalian cells is discussed along with the current limitations of this therapy. We also elaborate on approaches to improve the efficiency of suppression that include methods to enhance the effectiveness of current suppression drugs and the design or discovery of new, more effective suppression agents. Finally, we discuss the role of nonsense-mediated mRNA decay (NMD) in limiting the effectiveness of suppression therapy, and describe tactics that may allow the efficiency of NMD to be modulated in order to enhance suppression therapy.
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Affiliation(s)
- Kim M Keeling
- Department of Microbiology, Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
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Moser AB, Steinberg SJ, Watkins PA, Moser HW, Ramaswamy K, Siegmund KD, Lee DR, Ely JJ, Ryder OA, Hacia JG. Human and great ape red blood cells differ in plasmalogen levels and composition. Lipids Health Dis 2011; 10:101. [PMID: 21679470 PMCID: PMC3129581 DOI: 10.1186/1476-511x-10-101] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 06/17/2011] [Indexed: 02/06/2023] Open
Abstract
Background Plasmalogens are ether phospholipids required for normal mammalian developmental, physiological, and cognitive functions. They have been proposed to act as membrane antioxidants and reservoirs of polyunsaturated fatty acids as well as influence intracellular signaling and membrane dynamics. Plasmalogens are particularly enriched in cells and tissues of the human nervous, immune, and cardiovascular systems. Humans with severely reduced plasmalogen levels have reduced life spans, abnormal neurological development, skeletal dysplasia, impaired respiration, and cataracts. Plasmalogen deficiency is also found in the brain tissue of individuals with Alzheimer disease. Results In a human and great ape cohort, we measured the red blood cell (RBC) levels of the most abundant types of plasmalogens. Total RBC plasmalogen levels were lower in humans than bonobos, chimpanzees, and gorillas, but higher than orangutans. There were especially pronounced cross-species differences in the levels of plasmalogens with a C16:0 moiety at the sn-1 position. Humans on Western or vegan diets had comparable total RBC plasmalogen levels, but the latter group showed moderately higher levels of plasmalogens with a C18:1 moiety at the sn-1 position. We did not find robust sex-specific differences in human or chimpanzee RBC plasmalogen levels or composition. Furthermore, human and great ape skin fibroblasts showed only modest differences in peroxisomal plasmalogen biosynthetic activity. Human and chimpanzee microarray data indicated that genes involved in plasmalogen biosynthesis show cross-species differential expression in multiple tissues. Conclusion We propose that the observed differences in human and great ape RBC plasmalogens are primarily caused by their rates of biosynthesis and/or turnover. Gene expression data raise the possibility that other human and great ape cells and tissues differ in plasmalogen levels. Based on the phenotypes of humans and rodents with plasmalogen disorders, we propose that cross-species differences in tissue plasmalogen levels could influence organ functions and processes ranging from cognition to reproduction to aging.
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Affiliation(s)
- Ann B Moser
- Hugo W. Moser Research Institute at Kennedy Krieger, and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Mast FD, Li J, Virk MK, Hughes SC, Simmonds AJ, Rachubinski RA. A Drosophila model for the Zellweger spectrum of peroxisome biogenesis disorders. Dis Model Mech 2011; 4:659-72. [PMID: 21669930 PMCID: PMC3180231 DOI: 10.1242/dmm.007419] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human peroxisome biogenesis disorders are lethal genetic diseases in which abnormal peroxisome assembly compromises overall peroxisome and cellular function. Peroxisomes are ubiquitous membrane-bound organelles involved in several important biochemical processes, notably lipid metabolism and the use of reactive oxygen species for detoxification. Using cultured cells, we systematically characterized the peroxisome assembly phenotypes associated with dsRNA-mediated knockdown of 14 predicted Drosophila homologs of PEX genes (encoding peroxins; required for peroxisome assembly and linked to peroxisome biogenesis disorders), and confirmed that at least 13 of them are required for normal peroxisome assembly. We also demonstrate the relevance of Drosophila as a genetic model for the early developmental defects associated with the human peroxisome biogenesis disorders. Mutation of the PEX1 gene is the most common cause of peroxisome biogenesis disorders and is one of the causes of the most severe form of the disease, Zellweger syndrome. Inherited mutations in Drosophila Pex1 correlate with reproducible defects during early development. Notably, Pex1 mutant larvae exhibit abnormalities that are analogous to those exhibited by Zellweger syndrome patients, including developmental delay, poor feeding, severe structural abnormalities in the peripheral and central nervous systems, and early death. Finally, microarray analysis defined several clusters of genes whose expression varied significantly between wild-type and mutant larvae, implicating peroxisomal function in neuronal development, innate immunity, lipid and protein metabolism, gamete formation, and meiosis.
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Affiliation(s)
- Fred D Mast
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
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