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Olie CS, O'Brien DP, Jones HB, Liang Z, Damianou A, Sur-Erdem I, Pinto-Fernández A, Raz V, Kessler BM. Deubiquitinases in muscle physiology and disorders. Biochem Soc Trans 2024; 52:1085-1098. [PMID: 38716888 PMCID: PMC11346448 DOI: 10.1042/bst20230562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024]
Abstract
In vivo, muscle and neuronal cells are post-mitotic, and their function is predominantly regulated by proteostasis, a multilayer molecular process that maintains a delicate balance of protein homeostasis. The ubiquitin-proteasome system (UPS) is a key regulator of proteostasis. A dysfunctional UPS is a hallmark of muscle ageing and is often impacted in neuromuscular disorders (NMDs). Malfunction of the UPS often results in aberrant protein accumulation which can lead to protein aggregation and/or mis-localization affecting its function. Deubiquitinating enzymes (DUBs) are key players in the UPS, controlling protein turnover and maintaining the free ubiquitin pool. Several mutations in DUB encoding genes are linked to human NMDs, such as ATXN3, OTUD7A, UCHL1 and USP14, whilst other NMDs are associated with dysregulation of DUB expression. USP5, USP9X and USP14 are implicated in synaptic transmission and remodeling at the neuromuscular junction. Mice lacking USP19 show increased maintenance of lean muscle mass. In this review, we highlight the involvement of DUBs in muscle physiology and NMDs, particularly in processes affecting muscle regeneration, degeneration and inflammation following muscle injury. DUBs have recently garnered much respect as promising drug targets, and their roles in muscle maturation, regeneration and degeneration may provide the framework for novel therapeutics to treat muscular disorders including NMDs, sarcopenia and cachexia.
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Affiliation(s)
- Cyriel S. Olie
- Department of Human Genetics, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands
| | - Darragh P. O'Brien
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
| | - Hannah B.L. Jones
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
| | - Zhu Liang
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, U.K
| | - Andreas Damianou
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, U.K
| | - Ilknur Sur-Erdem
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, U.K
| | - Adán Pinto-Fernández
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, U.K
| | - Vered Raz
- Department of Human Genetics, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands
| | - Benedikt M. Kessler
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, U.K
- Chinese Academy for Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7FZ, U.K
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2
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Smith IC, Chakraborty S, Bourque PR, Sampaio ML, Melkus G, Lochmüller H, Woulfe J, Parks RJ, Brais B, Warman-Chardon J. Emerging and established biomarkers of oculopharyngeal muscular dystrophy. Neuromuscul Disord 2023; 33:824-834. [PMID: 37926637 DOI: 10.1016/j.nmd.2023.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 11/07/2023]
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a rare, primarily autosomal dominant, late onset muscular dystrophy commonly presenting with ptosis, dysphagia, and subsequent weakness of proximal muscles. Although OPMD diagnosis can be confirmed with high confidence by genetic testing, the slow progression of OPMD poses a significant challenge to clinical monitoring and a barrier to assessing the efficacy of treatments during clinical trials. Accordingly, there is a pressing need for more sensitive measures of OPMD progression, particularly those which do not require a muscle biopsy. This review provides an overview of progress in OPMD biomarkers from clinical assessment, quantitative imaging, histological assessments, and genomics, as well as hypothesis-generating "omics" approaches. The ongoing search for biomarkers relevant to OPMD progression needs an integrative, longitudinal approach combining validated and experimental approaches which may include clinical, imaging, demographic, and biochemical assessment methods. A multi-omics approach to biochemical biomarker discovery could help provide context for differences found between individuals with varying levels of disease activity and provide insight into pathomechanisms and prognosis of OPMD.
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Affiliation(s)
- Ian C Smith
- The Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | | | - Pierre R Bourque
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Medicine, The Ottawa Hospital/University of Ottawa, Ottawa, ON K1H 8L6, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada
| | - Marcos L Sampaio
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada; Department of Medical Imaging, The Ottawa Hospital, Ottawa, Ontario K1Y 4E9, Canada; Department of Radiology, Radiation Oncology and Medical Physics, University of Ottawa, Ottawa, ON K1H 8L6, Canada
| | - Gerd Melkus
- Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada; Department of Medical Imaging, The Ottawa Hospital, Ottawa, Ontario K1Y 4E9, Canada; Department of Physics, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Hanns Lochmüller
- The Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada; Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Medicine, The Ottawa Hospital/University of Ottawa, Ottawa, ON K1H 8L6, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada; Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON K1H 8L1, Canada
| | - John Woulfe
- The Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada; Department of Pathology and Laboratory Medicine, The Ottawa Hospital, Ottawa, ON K1Y 4E9, Canada
| | - Robin J Parks
- The Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada; Department of Medicine, The Ottawa Hospital/University of Ottawa, Ottawa, ON K1H 8L6, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada
| | - Bernard Brais
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Jodi Warman-Chardon
- The Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada; Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Department of Medicine, The Ottawa Hospital/University of Ottawa, Ottawa, ON K1H 8L6, Canada; Eric Poulin Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON K1Y 4E9, Canada; Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON K1H 8L1, Canada; Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec H3A 2B4, Canada.
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3
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Lin F, Yang K, Lin MT, Zheng FZ, Chen L, Ding YL, Ye ZX, Lin X, Wang N, Wang ZQ. The phenotypic and genotypic features of Chinese patients with oculopharyngeal muscular dystrophy. Ann Clin Transl Neurol 2023; 10:426-439. [PMID: 36691350 PMCID: PMC10014010 DOI: 10.1002/acn3.51733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/03/2023] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE Oculopharyngeal muscular dystrophy (OPMD) is a late-onset inherited neuromuscular disorder, with progressive ptosis and dysphagia as common manifestations. To date, OPMD has rarely been reported among East Asians. The present study summarizes the phenotypic and genotypic features of Chinese patients with OPMD. METHODS Twenty-one patients with molecularly confirmed OPMD from 9 unrelated families were identified by direct sequencing of the polyadenlyate binding protein nuclear-1 (PABPN1) gene. Immunofluorescence staining of muscle biopsies was conducted to identify the components of protein degradation pathways involved in OPMD. RESULTS In our cohort, the genetically confirmed OPMD group had a mean age at onset of 50.6 ± 4.2 years (range 45-60 years). Ptosis (42.9%) was the most common initial symptom; patients with ptosis as the first symptom subsequently developed dysphagia within a median time of 5.5 years (range 1-19 years). Evidence of external ophthalmoplegia was found in 38.1% of patients. A total of 33.3% of the patients developed muscle weakness at a median age at onset of 66 years (range 50-70 years), with neck flexor involvement in all patients. Five genotypes were observed in our cohort, including classical (GCG)9-11 repeats in 7 families and non-GCG elongations with additional GCA expansions in 2 families. OPMD muscle biopsies revealed rimmed vacuoles and intranuclear filamentous inclusions. The PABPN1 protein showed substantial accumulation in the nuclei of muscle fiber aggregates and closely colocalized with p62, LC3B and FK2. INTERPRETATION Our findings indicate wide genetic heterogeneity in OPMD in the Chinese population and demonstrate abnormalities in protein degradation pathways in this disease.
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Affiliation(s)
- Feng Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China
| | - Kang Yang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China
| | - Min-Ting Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China.,Fujian Key Laboratory of Molecular Neurology, 350005, Fuzhou, China
| | - Fu-Ze Zheng
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China.,Fujian Key Laboratory of Molecular Neurology, 350005, Fuzhou, China
| | - Long Chen
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China
| | - Yuan-Liang Ding
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China.,Fujian Key Laboratory of Molecular Neurology, 350005, Fuzhou, China
| | - Zhi-Xian Ye
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China
| | - Xin Lin
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China.,Fujian Key Laboratory of Molecular Neurology, 350005, Fuzhou, China
| | - Zhi-Qiang Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 350005, Fujian, Fuzhou, China.,Fujian Key Laboratory of Molecular Neurology, 350005, Fuzhou, China
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4
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Boulinguiez A, Roth F, Mouigni HR, Butler-Browne G, Mouly V, Trollet C. [Nuclear aggregates in oculopharyngeal muscular dystrophy]. Med Sci (Paris) 2022; 38 Hors série n° 1:13-16. [PMID: 36649629 DOI: 10.1051/medsci/2022175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is one of the diseases related to pathological expansions of trinucleotides. Its pathogenesis remains unclear although the presence of aggregates within the nuclei of the muscle fiber seems to play an important role. The basic research studies presented here help understand their composition and their deleterious role. These elements may result in new therapeutic avenues.
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Affiliation(s)
- Alexis Boulinguiez
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
| | - Fany Roth
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
| | - Hadidja Rose Mouigni
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
| | - Gillian Butler-Browne
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
| | - Vincent Mouly
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
| | - Capucine Trollet
- Sorbonne Université-Inserm, Centre de Recherche en Myologie, Institut de Myologie, Paris, France
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5
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Richard P, Stojkovic T, Metay C, Lacau St Guily J, Trollet C. Distrofia muscolare oculofaringea. Neurologia 2022. [DOI: 10.1016/s1634-7072(22)46725-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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6
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Mei H, Boom J, El Abdellaoui S, Abdelmohsen K, Munk R, Martindale JL, Kloet S, Kielbasa SM, Sharp TH, Gorospe M, Raz V. Alternative polyadenylation utilization results in ribosome assembly and mRNA translation deficiencies in a model for muscle aging. J Gerontol A Biol Sci Med Sci 2022; 77:1130-1140. [PMID: 35245938 PMCID: PMC9159670 DOI: 10.1093/gerona/glac058] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Indexed: 11/15/2022] Open
Abstract
Aging-associated muscle wasting is regulated by multiple molecular processes, whereby aberrant mRNA processing regulation induces muscle wasting. The poly(A)-binding protein nuclear 1 (PABPN1) regulates polyadenylation site (PAS) utilization, in the absence of PABPN1 the alternative PAS (APA) is utilized. Reduced PABPN1 levels induce muscle wasting where the expression of cellular processes regulating protein homeostasis, the ubiquitin-proteasome system, and translation, are robustly dysregulated. Translation is impacted by mRNA levels, but PABPN1 impact on translation is not fully understood. Here we show that a persistent reduction in PABPN1 levels led to a significant loss of translation efficiency. RNA sequencing of rRNA-depleted libraries from polysome traces revealed reduced mRNA abundance across ribosomal fractions, as well as reduced levels of small RNAs. We show that the abundance of translated mRNAs in the polysomes correlated with PAS switches at the 3'-UTR. Those mRNAs are enriched in cellular processes that are essential for proper muscle function. This study suggests that the effect of PABPN1 on translation efficiency impacts protein homeostasis in aging-associated muscle atrophy.
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Affiliation(s)
- Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jasper Boom
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden, The Netherlands
| | - Salma El Abdellaoui
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Kotb Abdelmohsen
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Rachel Munk
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Jennifer L Martindale
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Susan Kloet
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Szymone M Kielbasa
- Sequencing Analysis Support Core, Leiden University Medical Centre, Leiden, The Netherlands
| | - Thomas H Sharp
- Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden The Netherlands
| | - Myriam Gorospe
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Vered Raz
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
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7
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Ribot C, Soler C, Chartier A, Al Hayek S, Naït-Saïdi R, Barbezier N, Coux O, Simonelig M. Activation of the ubiquitin-proteasome system contributes to oculopharyngeal muscular dystrophy through muscle atrophy. PLoS Genet 2022; 18:e1010015. [PMID: 35025870 PMCID: PMC8791501 DOI: 10.1371/journal.pgen.1010015] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 01/26/2022] [Accepted: 01/01/2022] [Indexed: 12/05/2022] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late-onset disorder characterized by progressive weakness and degeneration of specific muscles. OPMD is due to extension of a polyalanine tract in poly(A) binding protein nuclear 1 (PABPN1). Aggregation of the mutant protein in muscle nuclei is a hallmark of the disease. Previous transcriptomic analyses revealed the consistent deregulation of the ubiquitin-proteasome system (UPS) in OPMD animal models and patients, suggesting a role of this deregulation in OPMD pathogenesis. Subsequent studies proposed that UPS contribution to OPMD involved PABPN1 aggregation. Here, we use a Drosophila model of OPMD to address the functional importance of UPS deregulation in OPMD. Through genome-wide and targeted genetic screens we identify a large number of UPS components that are involved in OPMD. Half dosage of UPS genes reduces OPMD muscle defects suggesting a pathological increase of UPS activity in the disease. Quantification of proteasome activity confirms stronger activity in OPMD muscles, associated with degradation of myofibrillar proteins. Importantly, improvement of muscle structure and function in the presence of UPS mutants does not correlate with the levels of PABPN1 aggregation, but is linked to decreased degradation of muscle proteins. Oral treatment with the proteasome inhibitor MG132 is beneficial to the OPMD Drosophila model, improving muscle function although PABPN1 aggregation is enhanced. This functional study reveals the importance of increased UPS activity that underlies muscle atrophy in OPMD. It also provides a proof-of-concept that inhibitors of proteasome activity might be an attractive pharmacological approach for OPMD. Oculopharyngeal muscular dystrophy (OPMD) is a genetic disease characterized by progressive weakness of specific muscles, leading to swallowing difficulties (dysphagia), eyelid drooping (ptosis) and walking difficulties at later stages. No drug treatments are currently available. OPMD is due to mutations in a nuclear protein called poly(A) binding protein nuclear 1 (PABPN1) that is involved in processing of different classes of RNAs in the nucleus. We have used an animal model of OPMD that we have developed in the fly Drosophila to investigate the role in OPMD of the ubiquitin-proteasome system, a pathway specialized in protein degradation. We report an increased activity of the ubiquitin-proteasome system that is associated with degradation of muscular proteins in the OPMD Drosophila model. We propose that higher activity of the ubiquitin-proteasome system leads to muscle atrophy in OPMD. Importantly, oral treatment of this OPMD animal model with an inhibitor of proteasome activity reduces muscle defects. A number of proteasome inhibitors are approved drugs used in clinic against cancers, therefore our results provide a proof-of-concept that inhibitors of proteasome might be of interest in future treatments of OPMD.
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Affiliation(s)
- Cécile Ribot
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
| | - Cédric Soler
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
| | - Aymeric Chartier
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
| | - Sandy Al Hayek
- GReD Laboratory, Clermont-Auvergne University, INSERM U1103, CNRS UMR6293, Clermont-Ferrand, France
| | - Rima Naït-Saïdi
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
| | - Nicolas Barbezier
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
| | - Olivier Coux
- Ubiquitin-proteasome system and cell cycle control, Montpellier Cell Biology Research Center, UMR5237 CNRS-Univ Montpellier, Montpellier, France
| | - Martine Simonelig
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, Montpellier, France
- * E-mail:
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8
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Bamia A, Sinane M, Naït-Saïdi R, Dhiab J, Keruzoré M, Nguyen PH, Bertho A, Soubigou F, Halliez S, Blondel M, Trollet C, Simonelig M, Friocourt G, Béringue V, Bihel F, Voisset C. Anti-prion Drugs Targeting the Protein Folding Activity of the Ribosome Reduce PABPN1 Aggregation. Neurotherapeutics 2021; 18:1137-1150. [PMID: 33533011 PMCID: PMC8423950 DOI: 10.1007/s13311-020-00992-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2020] [Indexed: 01/10/2023] Open
Abstract
Prion diseases are caused by the propagation of PrPSc, the pathological conformation of the PrPC prion protein. The molecular mechanisms underlying PrPSc propagation are still unsolved and no therapeutic solution is currently available. We thus sought to identify new anti-prion molecules and found that flunarizine inhibited PrPSc propagation in cell culture and significantly prolonged survival of prion-infected mice. Using an in silico therapeutic repositioning approach based on similarities with flunarizine chemical structure, we tested azelastine, duloxetine, ebastine, loperamide and metixene and showed that they all have an anti-prion activity. Like flunarizine, these marketed drugs reduced PrPSc propagation in cell culture and in mouse cerebellum organotypic slice culture, and inhibited the protein folding activity of the ribosome (PFAR). Strikingly, some of these drugs were also able to alleviate phenotypes due to PABPN1 nuclear aggregation in cell and Drosophila models of oculopharyngeal muscular dystrophy (OPMD). These data emphasize the therapeutic potential of anti-PFAR drugs for neurodegenerative and neuromuscular proteinopathies.
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Affiliation(s)
- Aline Bamia
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Maha Sinane
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Rima Naït-Saïdi
- Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, mRNA Regulation and Development, Montpellier, France
| | - Jamila Dhiab
- Sorbanne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, F75013, Paris, France
| | - Marc Keruzoré
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Phu Hai Nguyen
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
- Host Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Rocky Mountain Laboratories, Hamilton, MT, USA
| | - Agathe Bertho
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Flavie Soubigou
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Sophie Halliez
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
- Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Univ. Lille, F-59000, Lille, France
| | - Marc Blondel
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Capucine Trollet
- Sorbanne Université, Inserm, Institut de Myologie, Centre de Recherche en Myologie, F75013, Paris, France
| | - Martine Simonelig
- Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, mRNA Regulation and Development, Montpellier, France
| | | | - Vincent Béringue
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
| | - Frédéric Bihel
- Laboratoire d'Innovation Thérapeutique, LIT, UMR7200, IMS MEDALIS, Faculty of Pharmacy, CNRS, Université de Strasbourg, Illkirch, F-67400, France.
| | - Cécile Voisset
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200, Brest, France.
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9
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Raz V, Kroon RHMJM, Mei H, Riaz M, Buermans H, Lassche S, Horlings C, Swart BD, Kalf J, Harish P, Vissing J, Kielbasa S, van Engelen BGM. Age-Associated Salivary MicroRNA Biomarkers for Oculopharyngeal Muscular Dystrophy. Int J Mol Sci 2020; 21:ijms21176059. [PMID: 32842713 PMCID: PMC7503697 DOI: 10.3390/ijms21176059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/10/2020] [Accepted: 08/18/2020] [Indexed: 12/30/2022] Open
Abstract
Small non-coding microRNAs (miRNAs) are involved in the regulation of mRNA stability. Their features, including high stability and secretion to biofluids, make them attractive as potential biomarkers for diverse pathologies. This is the first study reporting miRNA as potential biomarkers for oculopharyngeal muscular dystrophy (OPMD), an adult-onset myopathy. We hypothesized that miRNA that is differentially expressed in affected muscles from OPMD patients is secreted to biofluids and those miRNAs could be used as biomarkers for OPMD. We first identified candidate miRNAs from OPMD-affected muscles and from muscles from an OPMD mouse model using RNA sequencing. We then compared the OPMD-deregulated miRNAs to the literature and, subsequently, we selected a few candidates for expression studies in serum and saliva biofluids using qRT-PCR. We identified 126 miRNAs OPMD-deregulated in human muscles, but 36 deregulated miRNAs in mice only (pFDR < 0.05). Only 15 OPMD-deregulated miRNAs overlapped between the in humans and mouse studies. The majority of the OPMD-deregulated miRNAs showed opposite deregulation direction compared with known muscular dystrophies miRNAs (myoMirs), which are associated. In contrast, similar dysregulation direction was found for 13 miRNAs that are common between OPMD and aging muscles. A significant age-association (p < 0.05) was found for 17 OPMD-deregulated miRNAs (13.4%), whereas in controls, only six miRNAs (1.4%) showed a significant age-association, suggesting that miRNA expression in OPMD is highly age-associated. miRNA expression in biofluids revealed that OPMD-associated deregulation in saliva was similar to that in muscles, but not in serum. The same as in muscle, miRNA expression levels in saliva were also found to be associated with age (p < 0.05). Moreover, the majority of OPMD-miRNAs were found to be associated with dysphagia as an initial symptom. We suggest that levels of specific miRNAs in saliva can mark muscle degeneration in general and dysphagia in OPMD.
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Affiliation(s)
- Vered Raz
- Department of Human Genetics, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands; (M.R.); (H.B.)
- Correspondence:
| | - Rosemarie H. M. J. M. Kroon
- Radboud University Medical Center, Department of Rehabilitation, Donders Institute for Brain, Cognition and Behaviour, 6525AJ Nijmegen, The Netherlands; (R.H.M.J.M.K.); (B.D.S.); (J.K.)
| | - Hailiang Mei
- Sequence Analysis Support Core, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands; (H.M.); (S.K.)
| | - Muhammad Riaz
- Department of Human Genetics, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands; (M.R.); (H.B.)
| | - Henk Buermans
- Department of Human Genetics, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands; (M.R.); (H.B.)
| | - Saskia Lassche
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6525AJ Nijmegen, The Netherlands; (S.L.); (C.H.); (B.G.M.v.E.)
| | - Corinne Horlings
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6525AJ Nijmegen, The Netherlands; (S.L.); (C.H.); (B.G.M.v.E.)
| | - Bert De Swart
- Radboud University Medical Center, Department of Rehabilitation, Donders Institute for Brain, Cognition and Behaviour, 6525AJ Nijmegen, The Netherlands; (R.H.M.J.M.K.); (B.D.S.); (J.K.)
| | - Johanna Kalf
- Radboud University Medical Center, Department of Rehabilitation, Donders Institute for Brain, Cognition and Behaviour, 6525AJ Nijmegen, The Netherlands; (R.H.M.J.M.K.); (B.D.S.); (J.K.)
| | - Pradeep Harish
- Centre of Gene and Cell Therapy, Royal Holloway, University of London, Egham TW2 0EX, UK;
| | - John Vissing
- The Copenhagen Neuromuscular Center, Righospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark;
| | - Szymon Kielbasa
- Sequence Analysis Support Core, Leiden University Medical Centre, 2333ZC Leiden, The Netherlands; (H.M.); (S.K.)
| | - Baziel G. M. van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6525AJ Nijmegen, The Netherlands; (S.L.); (C.H.); (B.G.M.v.E.)
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10
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Malerba A, Roth F, Harish P, Dhiab J, Lu-Nguyen N, Cappellari O, Jarmin S, Mahoudeau A, Ythier V, Lainé J, Negroni E, Abgueguen E, Simonelig M, Guedat P, Mouly V, Butler-Browne G, Voisset C, Dickson G, Trollet C. Pharmacological modulation of the ER stress response ameliorates oculopharyngeal muscular dystrophy. Hum Mol Genet 2020; 28:1694-1708. [PMID: 30649389 DOI: 10.1093/hmg/ddz007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/03/2019] [Accepted: 01/03/2019] [Indexed: 12/23/2022] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a rare late onset genetic disease leading to ptosis, dysphagia and proximal limb muscles at later stages. A short abnormal (GCN) triplet expansion in the polyA-binding protein nuclear 1 (PABPN1) gene leads to PABPN1-containing aggregates in the muscles of OPMD patients. Here we demonstrate that treating mice with guanabenz acetate (GA), an FDA-approved antihypertensive drug, reduces the size and number of nuclear aggregates, improves muscle force, protects myofibers from the pathology-derived turnover and decreases fibrosis. GA targets various cell processes, including the unfolded protein response (UPR), which acts to attenuate endoplasmic reticulum (ER) stress. We demonstrate that GA increases both the phosphorylation of the eukaryotic translation initiation factor 2α subunit and the splicing of Xbp1, key components of the UPR. Altogether these data show that modulation of protein folding regulation is beneficial for OPMD and promote the further development of GA or its derivatives for treatment of OPMD in humans. Furthermore, they support the recent evidences that treating ER stress could be therapeutically relevant in other more common proteinopathies.
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Affiliation(s)
- Alberto Malerba
- School of Biological Sciences, Centers of Gene and Cell Therapy and Biomedical Sciences, Royal Holloway, University of London, TW20 OEX Surrey, UK
| | - Fanny Roth
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Pradeep Harish
- School of Biological Sciences, Centers of Gene and Cell Therapy and Biomedical Sciences, Royal Holloway, University of London, TW20 OEX Surrey, UK
| | - Jamila Dhiab
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Ngoc Lu-Nguyen
- School of Biological Sciences, Centers of Gene and Cell Therapy and Biomedical Sciences, Royal Holloway, University of London, TW20 OEX Surrey, UK
| | - Ornella Cappellari
- Comparative Biomedical Sciences, The Royal Veterinary College, London, UK
| | - Susan Jarmin
- School of Biological Sciences, Centers of Gene and Cell Therapy and Biomedical Sciences, Royal Holloway, University of London, TW20 OEX Surrey, UK
| | - Alexandrine Mahoudeau
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Victor Ythier
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Jeanne Lainé
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Elisa Negroni
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | | | - Martine Simonelig
- Institute of Human Genetics, CNRS UMR9002-University of Montpellier, mRNA Regulation and Development, Montpellier, France
| | | | - Vincent Mouly
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Gillian Butler-Browne
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
| | - Cécile Voisset
- UMR1078 'Genetic, Functional Genomic and Biotechnologies', INSERM, EFS, Brest University, IBSAM, Brest, France
| | - George Dickson
- School of Biological Sciences, Centers of Gene and Cell Therapy and Biomedical Sciences, Royal Holloway, University of London, TW20 OEX Surrey, UK
| | - Capucine Trollet
- Sorbonne Université, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, UMRS974, 47 bd de l'Hôpital, Paris, France
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11
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Harish P, Malerba A, Lu-Nguyen N, Forrest L, Cappellari O, Roth F, Trollet C, Popplewell L, Dickson G. Inhibition of myostatin improves muscle atrophy in oculopharyngeal muscular dystrophy (OPMD). J Cachexia Sarcopenia Muscle 2019; 10:1016-1026. [PMID: 31066242 PMCID: PMC6818462 DOI: 10.1002/jcsm.12438] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/21/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscle disease affecting one per 80 000 of the general population characterized by profound dysphagia and ptosis, and limb weakness at later stages. Affected muscles are characterized by increased fibrosis and atrophy. Myostatin is a negative regulator of muscle mass, and inhibition of myostatin has been demonstrated to ameliorate symptoms in dystrophic muscles. METHODS In this study, we performed a systemic delivery of a monoclonal antibody to immunologically block myostatin in the A17 mouse model of OPMD. The mice were administered a weekly dose of 10 mg/kg RK35 intraperitonially for 10 weeks, following which histological analyses were performed on the samples. RESULTS This treatment significantly (P < 0.01) improved body mass (11%) and muscle mass (for the tibialis anterior and extensor digitorum longus by 19% and 41%) in the A17 mice treated with RK35 when compared to saline controls. Similarly, a significantly (P < 0.01) increased muscle strength (18% increase in maximal tetanic force) and myofibre diameter (17% and 44% for the tibialis anterior and extensor digitorum longus), and reduced expression of markers of muscle fibrosis (40% reduction in area of expression), was also observed. No change in the density of intranuclear inclusions (a hallmark of disease progression of OPMD) was however observed. CONCLUSIONS Our study supports the clinical translation of such antibody-mediated inhibition of myostatin as a treatment of OPMD. This strategy has implications to be used as adjuvant therapies with gene therapy based approaches, or to stabilize the muscle prior to myoblast transplantation.
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Affiliation(s)
- Pradeep Harish
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
| | - Alberto Malerba
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
| | - Ngoc Lu-Nguyen
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
| | - Leysa Forrest
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
| | | | - Fanny Roth
- Association Institut de Myologie, Centre de Recherche en Myologie UMRS974, Sorbonne Université, INSERM, Paris, France
| | - Capucine Trollet
- Association Institut de Myologie, Centre de Recherche en Myologie UMRS974, Sorbonne Université, INSERM, Paris, France
| | - Linda Popplewell
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
| | - George Dickson
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London, Surrey, UK
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12
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Deacetylation Inhibition Reverses PABPN1-Dependent Muscle Wasting. iScience 2019; 12:318-332. [PMID: 30739015 PMCID: PMC6370712 DOI: 10.1016/j.isci.2019.01.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/04/2018] [Accepted: 01/15/2019] [Indexed: 02/07/2023] Open
Abstract
Reduced poly(A)-binding protein nuclear 1 (PABPN1) levels cause aging-associated muscle wasting. PABPN1 is a multifunctional regulator of mRNA processing. To elucidate the molecular mechanisms causing PABPN1-mediated muscle wasting, we compared the transcriptome with the proteome in mouse muscles expressing short hairpin RNA to PABPN1 (shPab). We found greater variations in the proteome than in mRNA expression profiles. Protein accumulation in the shPab proteome was concomitant with reduced proteasomal activity. Notably, protein acetylation appeared to be decreased in shPab versus control proteomes (63%). Acetylome profiling in shPab muscles revealed prominent peptide deacetylation associated with elevated sirtuin-1 (SIRT1) deacetylase. We show that SIRT1 mRNA levels are controlled by PABPN1 via alternative polyadenylation site utilization. Most importantly, SIRT1 deacetylase inhibition by sirtinol increased PABPN1 levels and reversed muscle wasting. We suggest that perturbation of a multifactorial regulatory loop involving PABPN1 and SIRT1 plays an imperative role in aging-associated muscle wasting. Video Abstract
The PABPN1 transcriptome has smaller changes than its corresponding proteome The PABPN1 proteome is marked by protein deacetylation and elevated SIRT1 deacetylase SIRT1 levels are controlled by PABPN1 via alternative polyadenylation utilization Deacetylation inhibition reversed hallmark of muscle wasting in shPab muscles
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13
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West DWD, Marcotte GR, Chason CM, Juo N, Baehr LM, Bodine SC, Baar K. Normal Ribosomal Biogenesis but Shortened Protein Synthetic Response to Acute Eccentric Resistance Exercise in Old Skeletal Muscle. Front Physiol 2019; 9:1915. [PMID: 30692935 PMCID: PMC6339931 DOI: 10.3389/fphys.2018.01915] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/18/2018] [Indexed: 01/06/2023] Open
Abstract
Anabolic resistance to feeding in aged muscle is well-characterized; however, whether old skeletal muscle is intrinsically resistant to acute mechanical loading is less clear. The aim of this study was to determine the impact of aging on muscle protein synthesis (MPS), ribosome biogenesis, and protein breakdown in skeletal muscle following a single bout of resistance exercise. Adult male F344/BN rats aged 10 (Adult) and 30 (Old) months underwent unilateral maximal eccentric contractions of the hindlimb. Precursor rRNA increased early post-exercise (6-18 h), preceding elevations in ribosomal mass at 48 h in Adult and Old; there were no age-related differences in these responses. MPS increased early post-exercise in both Adult and Old; however, at 48 h of recovery, MPS returned to baseline in Old but not Adult. This abbreviated protein synthesis response in Old was associated with decreased levels of IRS1 protein and increased BiP, CHOP and eIF2α levels. Other than these responses, anabolic signaling was similar in Adult and Old muscle in the acute recovery phase. Basal proteasome activity was lower in Old, and resistance exercise did not increase the activity of either the ATP-dependent or independent proteasome, or autophagy (Cathepsin L activity) in either Adult or Old muscle. We conclude that MPS and ribosome biogenesis in response to maximal resistance exercise in old skeletal muscle are initially intact; however, the MPS response is abbreviated in Old, which may be the result of ER stress and/or blunted exercise-induced potentiation of the MPS response to feeding.
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Affiliation(s)
- Daniel W D West
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - George R Marcotte
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Courtney M Chason
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Natalie Juo
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States
| | - Leslie M Baehr
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Sue C Bodine
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
| | - Keith Baar
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States.,Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
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14
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Castets P, Frank S, Sinnreich M, Rüegg MA. "Get the Balance Right": Pathological Significance of Autophagy Perturbation in Neuromuscular Disorders. J Neuromuscul Dis 2018; 3:127-155. [PMID: 27854220 PMCID: PMC5271579 DOI: 10.3233/jnd-160153] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent research has revealed that autophagy, a major catabolic process in cells, is dysregulated in several neuromuscular diseases and contributes to the muscle wasting caused by non-muscle disorders (e.g. cancer cachexia) or during aging (i.e. sarcopenia). From there, the idea arose to interfere with autophagy or manipulate its regulatory signalling to help restore muscle homeostasis and attenuate disease progression. The major difficulty for the development of therapeutic strategies is to restore a balanced autophagic flux, due to the dynamic nature of autophagy. Thus, it is essential to better understand the mechanisms and identify the signalling pathways at play in the control of autophagy in skeletal muscle. A comprehensive analysis of the autophagic flux and of the causes of its dysregulation is required to assess the pathogenic role of autophagy in diseased muscle. Furthermore, it is essential that experiments distinguish between primary dysregulation of autophagy (prior to disease onset) and impairments as a consequence of the pathology. Of note, in most muscle disorders, autophagy perturbation is not caused by genetic modification of an autophagy-related protein, but rather through indirect alteration of regulatory signalling or lysosomal function. In this review, we will present the mechanisms involved in autophagy, and those ensuring its tight regulation in skeletal muscle. We will then discuss as to how autophagy dysregulation contributes to the pathogenesis of neuromuscular disorders and possible ways to interfere with this process to limit disease progression.
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Affiliation(s)
| | - Stephan Frank
- Institute of Pathology, Division of Neuropathology Basel University Hospital, Basel, Switzerland
| | - Michael Sinnreich
- Neuromuscular Research Center, Departments of Neurology and Biomedicine, Pharmazentrum, Basel, Switzerland
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15
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Raz V, Dickson G, 't Hoen PAC. Dysfunctional transcripts are formed by alternative polyadenylation in OPMD. Oncotarget 2017; 8:73516-73528. [PMID: 29088723 PMCID: PMC5650278 DOI: 10.18632/oncotarget.20640] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 08/03/2017] [Indexed: 11/25/2022] Open
Abstract
Post-transcription mRNA processing in the 3’-untranslated region (UTR) of transcripts alters mRNA landscape. Alternative polyadenylation (APA) utilization in the 3’-UTR often leads to shorter 3’-UTR affecting mRNA stability, a process that is regulated by PABPN1. In skeletal muscles PABPN1 levels reduce with age and a greater decrease in found in Oculopharyngeal muscular dystrophy (OPMD). OPMD is a late onset autosomal dominant myopathy caused by expansion mutation in PABPN1. In OPMD models a shift from distal to proximal polyadenylation site utilization in the 3’-UTR, and PABPN1 was shown to play a prominent role in APA. Whether PABPN1-mediated APA transcripts are functional is not fully understood. We investigate nuclear export and translation efficiency of transcripts in OPMD models. We focused on autophagy-regulated genes (ATGs) with APA utilization in cell models with reduced functional PABPN1. We provide evidence that ATGs transcripts from distal PAS retain in the nucleus and thus have reduced translation efficiency in cells with reduced PABPN1. In contrast, transcripts from proximal PAS showed a higher cytoplasmic abundance but a reduced occupancy in the ribosome. We therefore suggest that in reduced PABPN1 levels ATG transcripts from APA may not effectively translate to proteins. In those conditions we found constitutive autophagosome fusion and reduced autophagy flux. Augmentation of PABPN1 restored autophagosome fusion, suggesting that PABPN1-mediated APA plays a role in autophagy in OPMD and in aging muscles.
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Affiliation(s)
- Vered Raz
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - George Dickson
- School of Biological Science, Royal Holloway University of London, Egham, Surrey, United Kingdom
| | - Peter A C 't Hoen
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
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16
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Vest KE, Phillips BL, Banerjee A, Apponi LH, Dammer EB, Xu W, Zheng D, Yu J, Tian B, Pavlath GK, Corbett AH. Novel mouse models of oculopharyngeal muscular dystrophy (OPMD) reveal early onset mitochondrial defects and suggest loss of PABPN1 may contribute to pathology. Hum Mol Genet 2017; 26:3235-3252. [PMID: 28575395 PMCID: PMC5886286 DOI: 10.1093/hmg/ddx206] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/14/2017] [Accepted: 05/23/2017] [Indexed: 01/09/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late onset disease caused by polyalanine expansion in the poly(A) binding protein nuclear 1 (PABPN1). Several mouse models have been generated to study OPMD; however, most of these models have employed transgenic overexpression of alanine-expanded PABPN1. These models do not recapitulate the OPMD patient genotype and PABPN1 overexpression could confound molecular phenotypes. We have developed a knock-in mouse model of OPMD (Pabpn1+/A17) that contains one alanine-expanded Pabpn1 allele under the control of the native promoter and one wild-type Pabpn1 allele. This mouse is the closest available genocopy of OPMD patients. We show that Pabpn1+/A17 mice have a mild myopathic phenotype in adult and aged animals. We examined early molecular and biochemical phenotypes associated with expressing native levels of A17-PABPN1 and detected shorter poly(A) tails, modest changes in poly(A) signal (PAS) usage, and evidence of mitochondrial damage in these mice. Recent studies have suggested that a loss of PABPN1 function could contribute to muscle pathology in OPMD. To investigate a loss of function model of pathology, we generated a heterozygous Pabpn1 knock-out mouse model (Pabpn1+/Δ). Like the Pabpn1+/A17 mice, Pabpn1+/Δ mice have mild histologic defects, shorter poly(A) tails, and evidence of mitochondrial damage. However, the phenotypes detected in Pabpn1+/Δ mice only partially overlap with those detected in Pabpn1+/A17 mice. These results suggest that loss of PABPN1 function could contribute to but may not completely explain the pathology detected in Pabpn1+/A17 mice.
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Affiliation(s)
- Katherine E. Vest
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Brittany L. Phillips
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Ayan Banerjee
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Luciano H. Apponi
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Eric B. Dammer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Weiting Xu
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Dinghai Zheng
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Julia Yu
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Bin Tian
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Grace K. Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
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17
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Richard P, Roth F, Stojkovic T, Trollet C. Distrofia muscolare oculofaringea. Neurologia 2017. [DOI: 10.1016/s1634-7072(16)81777-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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18
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Riaz M, Raz Y, van der Slujis B, Dickson G, van Engelen B, Vissing J, Raz V. Cytokine genes as potential biomarkers for muscle weakness in OPMD. Hum Mol Genet 2016; 25:4282-4287. [PMID: 27506982 DOI: 10.1093/hmg/ddw259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/01/2016] [Accepted: 07/21/2016] [Indexed: 11/14/2022] Open
Abstract
Molecular biomarkers emerge as an accurate diagnostic tool, but are scarce for myopathies. Lack of outcome measures sensitive to disease onset and symptom severity hamper evaluation of therapeutic developments. Cytokines are circulating immunogenic molecules, and their potential as biomarkers has been exploited in the last decade. Cytokines are released from many tissues, including skeletal muscles, but their application to monitor muscle pathology is sparse. We report that the cytokine functional group is altered in the transcriptome of oculopharyngeal muscular dystrophy (OPMD). OPMD is a dominant, late-onset myopathy, caused by an alanine-expansion mutation in the gene encoding for poly(A) binding protein nuclear 1 (expPABPN1). Here, we investigated the hypothesis that cytokines could mark OPMD disease state. We determined cytokines levels the vastus lateralis muscle from genetically confirmed expPABPN1 carriers at a symptomatic or a presymptomatic stage. We identified cytokine-related genes candidates from a transcriptome study in a mouse overexpressing exp PABPN1 Six cytokines were found to be consistently down-regulated in OPMD vastus lateralis muscles. Expression levels of these cytokines were highly correlated in controls, but this correlation pattern was disrupted in OPMD. The levels of these 6 cytokines were not altered in expPABPN1 carriers at a pre-symptomatic stage, suggesting that this group of cytokines is a potential biomarker for muscle weakness in OPMD. Correlation pattern of expression levels could be a novel measurer for disease state.
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Affiliation(s)
- Muhammad Riaz
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Yotam Raz
- Department of Molecular Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - George Dickson
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Baziel van Engelen
- Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - John Vissing
- Department of Neurology, Rigshospitalet, Copenhagen Neuromuscular Center, University of Copenhagen, Denmark
| | - Vered Raz
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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19
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Klein P, Oloko M, Roth F, Montel V, Malerba A, Jarmin S, Gidaro T, Popplewell L, Perie S, Lacau St Guily J, de la Grange P, Antoniou MN, Dickson G, Butler-Browne G, Bastide B, Mouly V, Trollet C. Nuclear poly(A)-binding protein aggregates misplace a pre-mRNA outside of SC35 speckle causing its abnormal splicing. Nucleic Acids Res 2016; 44:10929-10945. [PMID: 27507886 PMCID: PMC5159528 DOI: 10.1093/nar/gkw703] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 11/21/2022] Open
Abstract
A short abnormal polyalanine expansion in the polyadenylate-binding protein nuclear-1 (PABPN1) protein causes oculopharyngeal muscular dystrophy (OPMD). Mutated PABPN1 proteins accumulate as insoluble intranuclear aggregates in muscles of OPMD patients. While the roles of PABPN1 in nuclear polyadenylation and regulation of alternative poly(A) site choice have been established, the molecular mechanisms which trigger pathological defects in OPMD and the role of aggregates remain to be determined. Using exon array, for the first time we have identified several splicing defects in OPMD. In particular, we have demonstrated a defect in the splicing regulation of the muscle-specific Troponin T3 (TNNT3) mutually exclusive exons 16 and 17 in OPMD samples compared to controls. This splicing defect is directly linked to the SC35 (SRSF2) splicing factor and to the presence of nuclear aggregates. As reported here, PABPN1 aggregates are able to trap TNNT3 pre-mRNA, driving it outside nuclear speckles, leading to an altered SC35-mediated splicing. This results in a decreased calcium sensitivity of muscle fibers, which could in turn plays a role in muscle pathology. We thus report a novel mechanism of alternative splicing deregulation that may play a role in various other diseases with nuclear inclusions or foci containing an RNA binding protein.
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Affiliation(s)
- Pierre Klein
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Martine Oloko
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Fanny Roth
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Valérie Montel
- Univ. Lille - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, équipe APMS, F-59000 Lille, France
| | - Alberto Malerba
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Susan Jarmin
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Teresa Gidaro
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Linda Popplewell
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Sophie Perie
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France.,Department of Otolaryngology-Head and Neck Surgery, University Pierre-et-Marie-Curie, Paris VI, Tenon Hospital, Assistance Publique des Hopitaux de Paris, Paris, France
| | - Jean Lacau St Guily
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France.,Department of Otolaryngology-Head and Neck Surgery, University Pierre-et-Marie-Curie, Paris VI, Tenon Hospital, Assistance Publique des Hopitaux de Paris, Paris, France
| | | | - Michael N Antoniou
- King's College London School of Medicine, Gene Expression and Therapy Group, Department of Medical and Molecular Genetics, Guy's Hospital, London, UK
| | - George Dickson
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Gillian Butler-Browne
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Bruno Bastide
- Univ. Lille - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, équipe APMS, F-59000 Lille, France
| | - Vincent Mouly
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
| | - Capucine Trollet
- Sorbonne Universités, UPMC Univ Paris 06, Centre de Recherche en Myologie, INSERM UMRS974, CNRS FRE3617, Institut de Myologie, 47 bd de l'Hôpital, 75013 Paris, France
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PABPN1-Dependent mRNA Processing Induces Muscle Wasting. PLoS Genet 2016; 12:e1006031. [PMID: 27152426 PMCID: PMC4859507 DOI: 10.1371/journal.pgen.1006031] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 04/08/2016] [Indexed: 11/19/2022] Open
Abstract
Poly(A) Binding Protein Nuclear 1 (PABPN1) is a multifunctional regulator of mRNA processing, and its expression levels specifically decline in aging muscles. An expansion mutation in PABPN1 is the genetic cause of oculopharyngeal muscle dystrophy (OPMD), a late onset and rare myopathy. Moreover, reduced PABPN1 expression correlates with symptom manifestation in OPMD. PABPN1 regulates alternative polyadenylation site (PAS) utilization. However, the impact of PAS utilization on cell and tissue function is poorly understood. We hypothesized that altered PABPN1 expression levels is an underlying cause of muscle wasting. To test this, we stably down-regulated PABPN1 in mouse tibialis anterior (TA) muscles by localized injection of adeno-associated viruses expressing shRNA to PABPN1 (shPab). We found that a mild reduction in PABPN1 levels causes muscle pathology including myofiber atrophy, thickening of extracellular matrix and myofiber-type transition. Moreover, reduced PABPN1 levels caused a consistent decline in distal PAS utilization in the 3’-UTR of a subset of OPMD-dysregulated genes. This alternative PAS utilization led to up-regulation of Atrogin-1, a key muscle atrophy regulator, but down regulation of proteasomal genes. Additionally reduced PABPN1 levels caused a reduction in proteasomal activity, and transition in MyHC isotope expression pattern in myofibers. We suggest that PABPN1-mediated alternative PAS utilization plays a central role in aging-associated muscle wasting. PABPN1 is a multifunctional regulator of mRNA processing and its levels are reduced in skeletal muscles from midlife onwards. Reduced PABPN1 levels in a mouse model causes muscle atrophy and muscle fiber switches. We show that PABPN1-regulated muscle atrophy is regulated, in part, by up regulation of Atrogin1 and reduced expression of proteasome genes via an alternative polyadenylation site utilization. This study reveals a functional role for alternative polyadenylation site utilization in muscle atrophy and suggests a role for RNA processing in muscle aging.
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The Inhibition of Heat Shock Protein 90 Facilitates the Degradation of Poly-Alanine Expanded Poly (A) Binding Protein Nuclear 1 via the Carboxyl Terminus of Heat Shock Protein 70-Interacting Protein. PLoS One 2015; 10:e0138936. [PMID: 26414348 PMCID: PMC4587574 DOI: 10.1371/journal.pone.0138936] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/06/2015] [Indexed: 01/24/2023] Open
Abstract
Background Since the identification of poly-alanine expanded poly(A) binding protein nuclear 1 (PABPN1) as the genetic cause of oculopharyngeal muscular dystrophy (OPMD), considerable progress has been made in our understanding of the pathogenesis of the disease. However, the molecular mechanisms that regulate the onset and progression of the disease remain unclear. Results In this study, we show that PABPN1 interacts with and is stabilized by heat shock protein 90 (HSP90). Treatment with the HSP90 inhibitor 17-AAG disrupted the interaction of mutant PABPN1 with HSP90 and reduced the formation of intranuclear inclusions (INIs). Furthermore, mutant PABPN1 was preferentially degraded in the presence of 17-AAG compared with wild-type PABPN1 in vitro and in vivo. The effect of 17-AAG was mediated through an increase in the interaction of PABPN1 with the carboxyl terminus of heat shock protein 70-interacting protein (CHIP). The overexpression of CHIP suppressed the aggregation of mutant PABPN1 in transfected cells. Conclusions Our results demonstrate that the HSP90 molecular chaperone system plays a crucial role in the selective elimination of abnormal PABPN1 proteins and also suggest a potential therapeutic application of the HSP90 inhibitor 17-AAG for the treatment of OPMD.
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Chartier A, Klein P, Pierson S, Barbezier N, Gidaro T, Casas F, Carberry S, Dowling P, Maynadier L, Bellec M, Oloko M, Jardel C, Moritz B, Dickson G, Mouly V, Ohlendieck K, Butler-Browne G, Trollet C, Simonelig M. Mitochondrial dysfunction reveals the role of mRNA poly(A) tail regulation in oculopharyngeal muscular dystrophy pathogenesis. PLoS Genet 2015; 11:e1005092. [PMID: 25816335 PMCID: PMC4376527 DOI: 10.1371/journal.pgen.1005092] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 02/23/2015] [Indexed: 01/25/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD), a late-onset disorder characterized by progressive degeneration of specific muscles, results from the extension of a polyalanine tract in poly(A) binding protein nuclear 1 (PABPN1). While the roles of PABPN1 in nuclear polyadenylation and regulation of alternative poly(A) site choice are established, the molecular mechanisms behind OPMD remain undetermined. Here, we show, using Drosophila and mouse models, that OPMD pathogenesis depends on affected poly(A) tail lengths of specific mRNAs. We identify a set of mRNAs encoding mitochondrial proteins that are down-regulated starting at the earliest stages of OPMD progression. The down-regulation of these mRNAs correlates with their shortened poly(A) tails and partial rescue of their levels when deadenylation is genetically reduced improves muscle function. Genetic analysis of candidate genes encoding RNA binding proteins using the Drosophila OPMD model uncovers a potential role of a number of them. We focus on the deadenylation regulator Smaug and show that it is expressed in adult muscles and specifically binds to the down-regulated mRNAs. In addition, the first step of the cleavage and polyadenylation reaction, mRNA cleavage, is affected in muscles expressing alanine-expanded PABPN1. We propose that impaired cleavage during nuclear cleavage/polyadenylation is an early defect in OPMD. This defect followed by active deadenylation of specific mRNAs, involving Smaug and the CCR4-NOT deadenylation complex, leads to their destabilization and mitochondrial dysfunction. These results broaden our understanding of the role of mRNA regulation in pathologies and might help to understand the molecular mechanisms underlying neurodegenerative disorders that involve mitochondrial dysfunction. Oculopharyngeal muscular dystrophy is a genetic disease characterized by progressive degeneration of specific muscles, leading to ptosis (eyelid drooping), dysphagia (swallowing difficulties) and proximal limb weakness. The disease results from mutations in a nuclear protein called poly(A) binding protein nuclear 1 that is involved in polyadenylation of messenger RNAs (mRNAs) and poly(A) site selection. To address the molecular mechanisms involved in the disease, we have used two animal models (Drosophila and mouse) that recapitulate the features of this disorder. We show that oculopharyngeal muscular dystrophy pathogenesis depends on defects in poly(A) tail length regulation of specific mRNAs. Because poly(A) tails play an essential role in mRNA stability, these defects result in accelerated decay of these mRNAs. The affected mRNAs encode mitochondrial proteins, and mitochondrial activity is impaired in diseased muscles. These findings have important implications for the development of potential therapies for oculopharyngeal muscular dystrophy, and might be relevant to decipher the molecular mechanisms underlying other disorders that involve mitochondrial dysfunction.
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Affiliation(s)
- Aymeric Chartier
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
| | - Pierre Klein
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - Stéphanie Pierson
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
| | - Nicolas Barbezier
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
| | - Teresa Gidaro
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - François Casas
- INRA, UMR 866 Différenciation cellulaire et croissance, Montpellier, France
| | - Steven Carberry
- Department of Biology, National University of Ireland, Maynooth, Ireland
| | - Paul Dowling
- Department of Biology, National University of Ireland, Maynooth, Ireland
| | - Laurie Maynadier
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
| | - Maëlle Bellec
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
| | - Martine Oloko
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - Claude Jardel
- Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, INSERM U1016, Institut Cochin, CNRS UMR 8104, AP-HP, GHU Pitié-Salpêtrière, Paris, France
| | - Bodo Moritz
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - George Dickson
- School of Biological Sciences, Royal Holloway - University of London, Egham, Surrey, United Kingdom
| | - Vincent Mouly
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - Kay Ohlendieck
- Department of Biology, National University of Ireland, Maynooth, Ireland
| | - Gillian Butler-Browne
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - Capucine Trollet
- Sorbonne Universités, UPMC Univ Paris 06, UM76, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Paris, France
| | - Martine Simonelig
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142, Montpellier, France
- * E-mail:
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Raz Y, Raz V. Oculopharyngeal muscular dystrophy as a paradigm for muscle aging. Front Aging Neurosci 2014; 6:317. [PMID: 25426070 PMCID: PMC4226162 DOI: 10.3389/fnagi.2014.00317] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 10/28/2014] [Indexed: 12/04/2022] Open
Abstract
Symptoms in late-onset neuromuscular disorders initiate only from midlife onward and progress with age. These disorders are primarily determined by identified hereditable mutations, but their late-onset symptom manifestation is not fully understood. Here, we review recent research developments on the late-onset autosomal dominant oculopharyngeal muscular dystrophy (OPMD). OPMD is caused by an expansion mutation in the gene encoding for poly-adenylate RNA binding protein1 (PABPN1). The molecular pathogenesis for the disease is still poorly understood. Despite a ubiquitous expression of PABPN1, symptoms in OPMD are limited to skeletal muscles. We discuss recent studies showing that PABPN1 levels in skeletal muscles are lower compared with other tissues, and specifically in skeletal muscles, PABPN1 expression declines from midlife onward. In OPMD, aggregation of expanded PABPN1 causes an additional decline in the level of the functional protein, which is associated with severe muscle weakness in OPMD. Reduced PABNPN1 expression in muscle cell culture causes myogenic defects, suggesting that PABPN1 loss-of-function causes muscle weakness in OPMD and in the elderly. Molecular signatures of OPMD muscles are similar to those of normal muscle aging, although expression trends progress faster in OPMD. We discuss a working hypothesis that aging-associated factors trigger late-onset symptoms in OPMD, and contribute to accelerated muscle weakness in OPMD. We focus on the pharyngeal and eyelid muscles, which are often affected in OPMD patients. We suggest that muscle weakness in OPMD is a paradigm for muscle aging.
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Affiliation(s)
- Yotam Raz
- Department of Human Genetics, Leiden University Medical Center , Leiden , Netherlands
| | - Vered Raz
- Department of Human Genetics, Leiden University Medical Center , Leiden , Netherlands
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Animal models in therapeutic drug discovery for oculopharyngeal muscular dystrophy. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e103-8. [PMID: 24050237 DOI: 10.1016/j.ddtec.2012.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late onset disease which affects specific muscles. No pharmacological treatments are currently available for OPMD. In recent years, genetically tractable models of OPMD – Drosophila and Caenorhabditis elegans – have been generated. Although these models have not yet been used for large-scale primary drug screening, they have been very useful in candidate approaches for the identification of potential therapeutic compounds for OPMD. In this brief review, we summarize the data that validated active molecules for OPMD in animal models including Drosophila, C. elegans and mouse.
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25
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A Novel Feed-Forward Loop between ARIH2 E3-Ligase and PABPN1 Regulates Aging-Associated Muscle Degeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1119-1131. [DOI: 10.1016/j.ajpath.2013.12.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/13/2013] [Accepted: 12/02/2013] [Indexed: 11/15/2022]
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Gheorghe M, Snoeck M, Emmerich M, Bäck T, Goeman JJ, Raz V. Major aging-associated RNA expressions change at two distinct age-positions. BMC Genomics 2014; 15:132. [PMID: 24524210 PMCID: PMC3930826 DOI: 10.1186/1471-2164-15-132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 02/07/2014] [Indexed: 11/10/2022] Open
Abstract
Background Genome-wide expression profiles are altered during biological aging and can describe molecular regulation of tissue degeneration. Age-regulated mRNA expression trends from cross-sectional studies could describe how aging progresses. We developed a novel statistical methodology to identify age-regulated expression trends in cross-sectional datasets. Results We studied six cross-sectional RNA expression profiles from different human tissues. Our methodology, capable of overcoming technical and genetic background differences, identified an age-regulation in four of the tissues. For the identification of expression trends, five regression models were compared and the quadratic model was found as the most suitable for this study. After k-means clustering of the age-associated probes, expression trends were found to change at two major age-positions in brain cortex and in Vastus lateralis muscles. The first age-position was found to occur during the fifth decade and a later one during the eighth decade. In kidney cortex, however, only one age-position was identified correlating with a late age-position. Functional mapping of genes at each age-position suggests that calcium homeostasis and lipid metabolisms are initially affected and subsequently, in elderly mitochondria, apoptosis and hormonal signaling pathways are affected. Conclusions Our results suggest that age-associated temporal changes in human tissues progress at distinct age-positions, which differ between tissues and in their molecular composition.
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Affiliation(s)
| | | | | | | | | | - Vered Raz
- Department of Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands.
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27
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Hwee DT, Baehr LM, Philp A, Baar K, Bodine SC. Maintenance of muscle mass and load-induced growth in Muscle RING Finger 1 null mice with age. Aging Cell 2014; 13:92-101. [PMID: 23941502 PMCID: PMC3947038 DOI: 10.1111/acel.12150] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2013] [Indexed: 12/18/2022] Open
Abstract
Age-related loss of muscle mass occurs to varying degrees in all individuals and has a detrimental effect on morbidity and mortality. Muscle RING Finger 1 (MuRF1), a muscle-specific E3 ubiquitin ligase, is believed to mediate muscle atrophy through the ubiquitin proteasome system (UPS). Deletion of MuRF1 (KO) in mice attenuates the loss of muscle mass following denervation, disuse, and glucocorticoid treatment; however, its role in age-related muscle loss is unknown. In this study, skeletal muscle from male wild-type (WT) and MuRF1 KO mice was studied up to the age of 24 months. Muscle mass and fiber cross-sectional area decreased significantly with age in WT, but not in KO mice. In aged WT muscle, significant decreases in proteasome activities, especially 20S and 26S β5 (20–40% decrease), were measured and were associated with significant increases in the maladaptive endoplasmic reticulum (ER) stress marker, CHOP. Conversely, in aged MuRF1 KO mice, 20S or 26S β5 proteasome activity was maintained or decreased to a lesser extent than in WT mice, and no increase in CHOP expression was measured. Examination of the growth response of older (18 months) mice to functional overload revealed that old WT mice had significantly less growth relative to young mice (1.37- vs. 1.83-fold), whereas old MuRF1 KO mice had a normal growth response (1.74- vs. 1.90-fold). These data collectively suggest that with age, MuRF1 plays an important role in the control of skeletal muscle mass and growth capacity through the regulation of cellular stress.
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Affiliation(s)
- Darren T. Hwee
- Departments of Neurobiology, Physiology, and Behavior; University of California Davis; Davis CA 95616 USA
- Molecular, Cellular and Integrative Physiology Graduate Group; University of California Davis; Davis CA 95616 USA
| | - Leslie M. Baehr
- Physiology and Membrane Biology; University of California Davis; Davis CA 95616 USA
| | - Andrew Philp
- Departments of Neurobiology, Physiology, and Behavior; University of California Davis; Davis CA 95616 USA
| | - Keith Baar
- Departments of Neurobiology, Physiology, and Behavior; University of California Davis; Davis CA 95616 USA
- Physiology and Membrane Biology; University of California Davis; Davis CA 95616 USA
| | - Sue C. Bodine
- Departments of Neurobiology, Physiology, and Behavior; University of California Davis; Davis CA 95616 USA
- Physiology and Membrane Biology; University of California Davis; Davis CA 95616 USA
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Goodwin M, Swanson MS. RNA-binding protein misregulation in microsatellite expansion disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:353-88. [PMID: 25201111 PMCID: PMC4483269 DOI: 10.1007/978-1-4939-1221-6_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RNA-binding proteins (RBPs) play pivotal roles in multiple cellular pathways from transcription to RNA turnover by interacting with RNA sequence and/or structural elements to form distinct RNA-protein complexes. Since these complexes are required for the normal regulation of gene expression, mutations that alter RBP functions may result in a cascade of deleterious events that lead to severe disease. Here, we focus on a group of hereditary disorders, the microsatellite expansion diseases, which alter RBP activities and result in abnormal neurological and neuromuscular phenotypes. While many of these diseases are classified as adult-onset disorders, mounting evidence indicates that disruption of normal RNA-protein interaction networks during embryogenesis modifies developmental pathways, which ultimately leads to disease manifestations later in life. Efforts to understand the molecular basis of these disorders has already uncovered novel pathogenic mechanisms, including RNA toxicity and repeat-associated non-ATG (RAN) translation, and current studies suggest that additional surprising insights into cellular regulatory pathways will emerge in the future.
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Affiliation(s)
- Marianne Goodwin
- Department of Molecular Genetics and Microbiology, University of Florida, College of Medicine, Cancer Genetics Research Complex, 2033 Mowry Road, Gainesville, FL, 32610-3610, USA
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Anvar SY, Raz Y, Verway N, van der Sluijs B, Venema A, Goeman JJ, Vissing J, van der Maarel SM, 't Hoen PAC, van Engelen BGM, Raz V. A decline in PABPN1 induces progressive muscle weakness in oculopharyngeal muscle dystrophy and in muscle aging. Aging (Albany NY) 2013; 5:412-26. [PMID: 23793615 PMCID: PMC3824410 DOI: 10.18632/aging.100567] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is caused by trinucleotide repeat expansion mutations in Poly(A) binding protein 1 (PABPN1). PABPN1 is a regulator of mRNA stability and is ubiquitously expressed. Here we investigated how symptoms in OPMD initiate only at midlife and why a subset of skeletal muscles is predominantly affected. Genome-wide RNA expression profiles from Vastus lateralis muscles human carriers of expanded-PABPN1 at pre-symptomatic and symptomatic stages were compared with healthy controls. Major expression changes were found to be associated with age rather than with expression of expanded-PABPN1, instead transcriptomes of OPMD and elderly muscles were significantly similar (P<0.05). Using k-means clustering we identified age-dependent trends in both OPMD and controls, but trends were often accelerated in OPMD. We report an age-regulated decline in PABPN1 levels in Vastus lateralis muscles from the fifth decade. In concurrence with severe muscle degeneration in OPMD, the decline in PABPN1 accelerated in OPMD and was specific to skeletal muscles. Reduced PABPN1 levels (30% to 60%) in muscle cells induced myogenic defects and morphological signatures of cellular aging in proportion to PABPN1 expression levels. We suggest that PABPN1 levels regulate muscle cell aging and OPMD represents an accelerated muscle aging disorder.
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Affiliation(s)
- Seyed Yahya Anvar
- Center for Human and Clinical Genetics, Leiden University Medical Center, the Netherlands
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30
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Raz V, Sterrenburg E, Routledge S, Venema A, van der Sluijs BM, Trollet C, Dickson G, van Engelen BGM, van der Maarel SM, Antoniou MN. Nuclear entrapment and extracellular depletion of PCOLCE is associated with muscle degeneration in oculopharyngeal muscular dystrophy. BMC Neurol 2013; 13:70. [PMID: 23815790 PMCID: PMC3717027 DOI: 10.1186/1471-2377-13-70] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 06/20/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Muscle fibrosis characterizes degenerated muscles in muscular dystrophies and in late onset myopathies. Fibrotic muscles often exhibit thickening of the extracellular matrix (ECM). The molecular regulation of this process is not fully understood. In oculopharyngeal muscular dystrophy (OPMD), an expansion of an alanine tract at the N-terminus of poly(A)-binding protein nuclear 1 (PABPN1) causes muscle symptoms. OPMD patient muscle degeneration initiates after midlife, while at an earlier age carriers of alanine expansion mutant PABPN1 (expPABPN1) are clinically pre-symptomatic. OPMD is characterized by fibrosis in skeletal muscles but the causative molecular mechanisms are not fully understood. METHODS We studied the molecular processes that are involved in OPMD pathology using cross-species mRNA expression profiles in muscles from patients and model systems. We identified significant dysregulation of the ECM functional group, among which the procollagen C-endopeptidase enhancer 1 gene (PCOLCE) was consistently down-regulated across species. We investigated PCOLCE subcellular localization in OPMD muscle samples and OPMD model systems to investigate any functional relevance of PCOLCE down-regulation in this disease. RESULTS We found that muscle degeneration in OPMD is associated with PCOLCE down-regulation. In addition to its known presence at the ECM, we also found PCOLCE within the nucleus of muscle cells. PCOLCE sub-cellular localization changes during myoblast cell fusion and is disrupted in cells expressing mutant expPABPN1. Our results show that PCOLCE binds to soluble PABPN1 and co-localizes with aggregated PABPN1 with a preference for the mutant protein. In muscle biopsies from OPMD patients we find that extracellular PCOLCE is depleted with its concomitant enrichment within the nuclear compartment. CONCLUSIONS PCOLCE regulates collagen processing at the ECM. Depletion of extracellular PCOLCE is associated with the expression of expPABPN1 in OPMD patient muscles. PCOLCE is also localized within the nucleus where it binds to PABPN1, suggesting that PCOLCE shuttles between the ECM and the nucleus. PCOLCE preferentially binds to expPABPN1. Nuclear-localized PCOLCE is enriched in muscle cells expressing expPABPN1. We suggest that nuclear entrapment of PCOLCE and its extracellular depletion represents a novel molecular mechanism in late-onset muscle fibrosis.
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Affiliation(s)
- Vered Raz
- Center for Human and Clinical Genetics, Leiden University Medical Center, Einthovenweg 20, Leiden, The Netherlands.
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Raz V, Butler-Browne G, van Engelen B, Brais B. 191st ENMC International Workshop: Recent advances in oculopharyngeal muscular dystrophy research: From bench to bedside 8-10 June 2012, Naarden, The Netherlands. Neuromuscul Disord 2013; 23:516-23. [DOI: 10.1016/j.nmd.2013.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Indexed: 10/27/2022]
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Banerjee A, Apponi LH, Pavlath GK, Corbett AH. PABPN1: molecular function and muscle disease. FEBS J 2013; 280:4230-50. [PMID: 23601051 DOI: 10.1111/febs.12294] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 12/17/2022]
Abstract
The polyadenosine RNA binding protein polyadenylate-binding nuclear protein 1 (PABPN1) plays key roles in post-transcriptional processing of RNA. Although PABPN1 is ubiquitously expressed and presumably contributes to control of gene expression in all tissues, mutation of the PABPN1 gene causes the disease oculopharyngeal muscular dystrophy (OPMD), in which a limited set of skeletal muscles are affected. A major goal in the field of OPMD research is to understand why mutation of a ubiquitously expressed gene leads to a muscle-specific disease. PABPN1 plays a well-documented role in controlling the poly(A) tail length of RNA transcripts but new functions are emerging through studies that exploit a variety of unbiased screens as well as model organisms. This review addresses (a) the molecular function of PABPN1 incorporating recent findings that reveal novel cellular functions for PABPN1 and (b) the approaches that are being used to understand the molecular defects that stem from expression of mutant PABPN1. The long-term goal in this field of research is to understand the key molecular functions of PABPN1 in muscle as well as the mechanisms that underlie the pathological consequences of mutant PABPN1. Armed with this information, researchers can seek to develop therapeutic approaches to enhance the quality of life for patients afflicted with OPMD.
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Affiliation(s)
- Ayan Banerjee
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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de Klerk E, Venema A, Anvar SY, Goeman JJ, Hu O, Trollet C, Dickson G, den Dunnen JT, van der Maarel SM, Raz V, 't Hoen PAC. Poly(A) binding protein nuclear 1 levels affect alternative polyadenylation. Nucleic Acids Res 2012; 40:9089-101. [PMID: 22772983 PMCID: PMC3467053 DOI: 10.1093/nar/gks655] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The choice for a polyadenylation site determines the length of the 3′-untranslated region (3′-UTRs) of an mRNA. Inclusion or exclusion of regulatory sequences in the 3′-UTR may ultimately affect gene expression levels. Poly(A) binding protein nuclear 1 (PABPN1) is involved in polyadenylation of pre-mRNAs. An alanine repeat expansion in PABPN1 (exp-PABPN1) causes oculopharyngeal muscular dystrophy (OPMD). We hypothesized that previously observed disturbed gene expression patterns in OPMD muscles may have been the result of an effect of PABPN1 on alternative polyadenylation, influencing mRNA stability, localization and translation. A single molecule polyadenylation site sequencing method was developed to explore polyadenylation site usage on a genome-wide level in mice overexpressing exp-PABPN1. We identified 2012 transcripts with altered polyadenylation site usage. In the far majority, more proximal alternative polyadenylation sites were used, resulting in shorter 3′-UTRs. 3′-UTR shortening was generally associated with increased expression. Similar changes in polyadenylation site usage were observed after knockdown or overexpression of expanded but not wild-type PABPN1 in cultured myogenic cells. Our data indicate that PABPN1 is important for polyadenylation site selection and that reduced availability of functional PABPN1 in OPMD muscles results in use of alternative polyadenylation sites, leading to large-scale deregulation of gene expression.
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Affiliation(s)
- Eleonora de Klerk
- Center for Human and Clinical Genetics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
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Bengoechea R, Tapia O, Casafont I, Berciano J, Lafarga M, Berciano MT. Nuclear speckles are involved in nuclear aggregation of PABPN1 and in the pathophysiology of oculopharyngeal muscular dystrophy. Neurobiol Dis 2012; 46:118-29. [PMID: 22249111 DOI: 10.1016/j.nbd.2011.12.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 12/19/2011] [Accepted: 12/31/2011] [Indexed: 10/14/2022] Open
Abstract
Nuclear speckles are essential nuclear compartments involved in the assembly, delivery and recycling of pre-mRNA processing factors, and in the post-transcriptional processing of pre-mRNAs. Oculopharyngeal muscular dystrophy (OPMD) is caused by a small expansion of the polyalanine tract in the poly(A)-binding protein nuclear 1 (PABPN1). Aggregation of expanded PABPN1 into intranuclear inclusions (INIs) in skeletal muscle fibers is the pathological hallmark of OPMD. In this study what we have analyzed in muscle fibers of OPMD patients and in primary cultures of human myoblasts are the relationships between nuclear speckles and INIs, and the contribution of the former to the biogenesis of the latter. While nuclear speckles concentrate snRNP splicing factors and PABPN1 in control muscle fibers, they are depleted of PABPN1 and appear closely associated with INIs in muscle fibers of OPMD patients. The induction of INI formation in human myoblasts expressing either wild type GFP-PABPN1 or expanded GFP-PABPN1-17ala demonstrates that the initial aggregation of PABPN1 proteins and their subsequent growth in INIs occurs at the edges of the nuclear speckles. Moreover, the growing of INIs gradually depletes PABPN1 proteins and poly(A) RNA from nuclear speckles, although the existence of these nuclear compartments is preserved. Time-lapse experiments in cultured myoblasts confirm nuclear speckles as biogenesis sites of PABPN1 inclusions. Given the functional importance of nuclear speckles in the post-transcriptional processing of pre-mRNAs, the INI-dependent molecular reorganization of these nuclear compartments in muscle fibers may cause a severe dysfunction in nuclear trafficking and processing of polyadenylated mRNAs, thereby contributing to the molecular pathophysiology of OPMD. Our results emphasize the potential importance of nuclear speckles as nuclear targets of neuromuscular disorders.
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Affiliation(s)
- Rocío Bengoechea
- Department of Anatomy and Cell Biology and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, University of Cantabria, Santander, Spain
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Anvar SY, Tucker A, Vinciotti V, Venema A, van Ommen GJB, van der Maarel SM, Raz V, 't Hoen PAC. Interspecies translation of disease networks increases robustness and predictive accuracy. PLoS Comput Biol 2011; 7:e1002258. [PMID: 22072955 PMCID: PMC3207951 DOI: 10.1371/journal.pcbi.1002258] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 09/16/2011] [Indexed: 02/03/2023] Open
Abstract
Gene regulatory networks give important insights into the mechanisms underlying physiology and pathophysiology. The derivation of gene regulatory networks from high-throughput expression data via machine learning strategies is problematic as the reliability of these models is often compromised by limited and highly variable samples, heterogeneity in transcript isoforms, noise, and other artifacts. Here, we develop a novel algorithm, dubbed Dandelion, in which we construct and train intraspecies Bayesian networks that are translated and assessed on independent test sets from other species in a reiterative procedure. The interspecies disease networks are subjected to multi-layers of analysis and evaluation, leading to the identification of the most consistent relationships within the network structure. In this study, we demonstrate the performance of our algorithms on datasets from animal models of oculopharyngeal muscular dystrophy (OPMD) and patient materials. We show that the interspecies network of genes coding for the proteasome provide highly accurate predictions on gene expression levels and disease phenotype. Moreover, the cross-species translation increases the stability and robustness of these networks. Unlike existing modeling approaches, our algorithms do not require assumptions on notoriously difficult one-to-one mapping of protein orthologues or alternative transcripts and can deal with missing data. We show that the identified key components of the OPMD disease network can be confirmed in an unseen and independent disease model. This study presents a state-of-the-art strategy in constructing interspecies disease networks that provide crucial information on regulatory relationships among genes, leading to better understanding of the disease molecular mechanisms.
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Affiliation(s)
- Seyed Yahya Anvar
- Center for Human and Clinical Genetics, Leiden University Medical Center, The Netherlands.
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Modeling oculopharyngeal muscular dystrophy in myotube cultures reveals reduced accumulation of soluble mutant PABPN1 protein. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1988-2000. [PMID: 21854744 DOI: 10.1016/j.ajpath.2011.06.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/07/2011] [Accepted: 06/21/2011] [Indexed: 12/17/2022]
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease caused by an alanine tract expansion mutation in poly(A) binding protein nuclear 1 (expPABPN1). To model OPMD in a myogenic and physiological context, we generated mouse myoblast cell clones stably expressing either human wild type (WT) or expPABPN1 at low levels. Transgene expression is induced on myotube differentiation and results in formation of insoluble nuclear PABPN1 aggregates that are similar to those observed in patients with OPMD. Quantitative analysis of PABPN1 in myotube cultures revealed that expPABPN1 accumulation and aggregation is greater than that of the WT protein. We found that aggregation of expPABPN1 is more affected than WT PABPN1 by inhibition of proteasome activity. Consistent with this, in myotube cultures expressing expPABPN1, deregulation of the proteasome was identified as the most significantly perturbed pathway. Differences in the accumulation of soluble WT and expPABPN1 were consistent with differences in ubiquitination and rate of protein turnover. This study demonstrates, for the first time to our knowledge, that, in myotubes, the ratio of soluble/insoluble expPABPN1 is significantly lower compared with that of the WT protein. We suggest that this difference can contribute to muscle weakness in OPMD.
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