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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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2
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Ishtayeh H, Galves M, Barnatan TT, Berdichevsky Y, Amer‐Sarsour F, Pasmanik‐Chor M, Braverman I, Blumen SC, Ashkenazi A. Oculopharyngeal muscular dystrophy mutations link the RNA-binding protein HNRNPQ to autophagosome biogenesis. Aging Cell 2023; 22:e13949. [PMID: 37559347 PMCID: PMC10577562 DOI: 10.1111/acel.13949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 06/22/2023] [Accepted: 07/15/2023] [Indexed: 08/11/2023] Open
Abstract
Autophagy is an intracellular degradative process with an important role in cellular homeostasis. Here, we show that the RNA binding protein (RBP), heterogeneous nuclear ribonucleoprotein Q (HNRNPQ)/SYNCRIP is required to stimulate early events in autophagosome biogenesis, in particular the induction of VPS34 kinase by ULK1-mediated beclin 1 phosphorylation. The RBPs HNRNPQ and poly(A) binding protein nuclear 1 (PABPN1) form a regulatory network that controls the turnover of distinct autophagy-related (ATG) proteins. We also show that oculopharyngeal muscular dystrophy (OPMD) mutations engender a switch from autophagosome stimulation to autophagosome inhibition by impairing PABPN1 and HNRNPQ control of the level of ULK1. The overexpression of HNRNPQ in OPMD patient-derived cells rescues the defective autophagy in these cells. Our data reveal a regulatory mechanism of autophagy induction that is compromised by PABPN1 disease mutations, and may thus further contribute to their deleterious effects.
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Affiliation(s)
- Hasan Ishtayeh
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Margarita Galves
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Tania T. Barnatan
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Yevgeny Berdichevsky
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Fatima Amer‐Sarsour
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Metsada Pasmanik‐Chor
- Bioinformatics Unit, G.S. Wise Faculty of Life ScienceTel Aviv UniversityTel AvivIsrael
| | - Itzhak Braverman
- Department of Otolaryngology, Head and Neck SurgeryHillel Yaffe Medical CenterHaderaIsrael
- Rappaport Faculty of Medicine, TechnionHaifaIsrael
| | - Sergiu C. Blumen
- Rappaport Faculty of Medicine, TechnionHaifaIsrael
- Department of NeurologyHillel Yaffe Medical CenterHaderaIsrael
| | - Avraham Ashkenazi
- The Department of Cell and Developmental Biology, Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
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Guan WL, Jiang LL, Yin XF, Hu HY. PABPN1 aggregation is driven by Ala expansion and poly(A)-RNA binding, leading to CFIm25 sequestration that impairs alternative polyadenylation. J Biol Chem 2023; 299:105019. [PMID: 37422193 PMCID: PMC10403730 DOI: 10.1016/j.jbc.2023.105019] [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: 03/08/2023] [Revised: 06/24/2023] [Accepted: 06/26/2023] [Indexed: 07/10/2023] Open
Abstract
Poly(A)-binding protein nuclear 1 (PABPN1) is an RNA-binding protein localized in nuclear speckles, while its alanine (Ala)-expanded variants accumulate as intranuclear aggregates in oculopharyngeal muscular dystrophy. The factors that drive PABPN1 aggregation and its cellular consequences remain largely unknown. Here, we investigated the roles of Ala stretch and poly(A) RNA in the phase transition of PABPN1 using biochemical and molecular cell biology methods. We have revealed that the Ala stretch controls its mobility in nuclear speckles, and Ala expansion leads to aggregation from the dynamic speckles. Poly(A) nucleotide is essential to the early-stage condensation that thereby facilitates speckle formation and transition to solid-like aggregates. Moreover, the PABPN1 aggregates can sequester CFIm25, a component of the pre-mRNA 3'-UTR processing complex, in an mRNA-dependent manner and consequently impair the function of CFIm25 in alternative polyadenylation. In conclusion, our study elucidates a molecular mechanism underlying PABPN1 aggregation and sequestration, which will be beneficial for understanding PABPN1 proteinopathy.
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Affiliation(s)
- Wen-Liang Guan
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Fang Yin
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
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Zhang Y, Zeuthen C, Zhu C, Wu F, Mezzell AT, Whitlow TJ, Choo HJ, Vest KE. Pharyngeal pathology in a mouse model of oculopharyngeal muscular dystrophy is associated with impaired basal autophagy in myoblasts. Front Cell Dev Biol 2022; 10:986930. [PMID: 36313551 PMCID: PMC9614327 DOI: 10.3389/fcell.2022.986930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/26/2022] [Indexed: 11/05/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late-onset dominant disease that primarily affects craniofacial muscles. Despite the fact that the genetic cause of OPMD is known to be expansion mutations in the gene encoding the nuclear polyadenosine RNA binding protein PABPN1, the molecular mechanisms of pathology are unknown and no pharmacologic treatments are available. Due to the limited availability of patient tissues, several animal models have been employed to study the pathology of OPMD. However, none of these models have demonstrated functional deficits in the muscles of the pharynx, which are predominantly affected by OPMD. Here, we used a knock-in mouse model of OPMD, Pabpn1 +/A17 , that closely genocopies patients. In Pabpn1 +/A17 mice, we detected impaired pharyngeal muscle function, and impaired pharyngeal satellite cell proliferation and fusion. Molecular studies revealed that basal autophagy, which is required for normal satellite cell function, is higher in pharynx-derived myoblasts than in myoblasts derived from limb muscles. Interestingly, basal autophagy is impaired in cells derived from Pabpn1 +/A17 mice. Pabpn1 knockdown in pharyngeal myoblasts failed to recapitulate the autophagy defect detected in Pabpn1 +/A17 myoblasts suggesting that loss of PABPN1 function does not contribute to the basal autophagy defect. Taken together, these studies provide the first evidence for pharyngeal muscle and satellite cell pathology in a mouse model of OPMD and suggest that aberrant gain of PABPN1 function contributes to the craniofacial pathology in OPMD.
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Affiliation(s)
- Yu Zhang
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Christopher Zeuthen
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Carol Zhu
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Fang Wu
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Allison T. Mezzell
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Thomas J. Whitlow
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Hyojung J. Choo
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Katherine E. Vest
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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5
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Newton AH, Pask AJ. Evolution and expansion of the RUNX2 QA repeat corresponds with the emergence of vertebrate complexity. Commun Biol 2020; 3:771. [PMID: 33319865 PMCID: PMC7738678 DOI: 10.1038/s42003-020-01501-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/10/2020] [Indexed: 11/08/2022] Open
Abstract
Runt-related transcription factor 2 (RUNX2) is critical for the development of the vertebrate bony skeleton. Unlike other RUNX family members, RUNX2 possesses a variable poly-glutamine, poly-alanine (QA) repeat domain. Natural variation within this repeat is able to alter the transactivation potential of RUNX2, acting as an evolutionary 'tuning knob' suggested to influence mammalian skull shape. However, the broader role of the RUNX2 QA repeat throughout vertebrate evolution is unknown. In this perspective, we examine the role of the RUNX2 QA repeat during skeletal development and discuss how its emergence and expansion may have facilitated the evolution of morphological novelty in vertebrates.
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Affiliation(s)
- Axel H Newton
- Biosciences 4, The School of Biosciences, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia.
- Anatomy and Developmental Biology, The School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Andrew J Pask
- Biosciences 4, The School of Biosciences, The University of Melbourne, Royal Parade, Parkville, VIC, 3052, Australia
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Olie CS, van der Wal E, Cikes D, Maton L, de Greef JC, Lin IH, Chen YF, Kareem E, Penninger JM, Kessler BM, Raz V. Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability. Sci Rep 2020; 10:17621. [PMID: 33077830 PMCID: PMC7572364 DOI: 10.1038/s41598-020-74676-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 09/28/2020] [Indexed: 12/30/2022] Open
Abstract
Muscle wasting and atrophy are regulated by multiple molecular processes, including mRNA processing. Reduced levels of the polyadenylation binding protein nucleus 1 (PABPN1), a multifactorial regulator of mRNA processing, cause muscle atrophy. A proteomic study in muscles with reduced PABPN1 levels suggested dysregulation of sarcomeric and cytoskeletal proteins. Here we investigated the hypothesis that reduced PABPN1 levels lead to an aberrant organization of the cytoskeleton. MURC, a plasma membrane-associated protein, was found to be more abundant in muscles with reduced PABPN1 levels, and it was found to be expressed at regions showing regeneration. A polarized cytoskeletal organization is typical for muscle cells, but muscle cells with reduced PABPN1 levels (named as shPAB) were characterized by a disorganized cytoskeleton that lacked polarization. Moreover, cell mechanical features and myogenic differentiation were significantly reduced in shPAB cells. Importantly, restoring cytoskeletal stability, by actin overexpression, was beneficial for myogenesis, expression of sarcomeric proteins and proper localization of MURC in shPAB cell cultures and in shPAB muscle bundle. We suggest that poor cytoskeletal mechanical features are caused by altered expression levels of cytoskeletal proteins and contribute to muscle wasting and atrophy.
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Affiliation(s)
| | - Erik van der Wal
- Human Genetics Department, Leiden University Medical Center, Leiden, The Netherlands
| | - Domagoj Cikes
- IMBA-Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Loes Maton
- Human Genetics Department, Leiden University Medical Center, Leiden, The Netherlands
| | - Jessica C de Greef
- Human Genetics Department, Leiden University Medical Center, Leiden, The Netherlands
| | - I-Hsuan Lin
- VYM Genome Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Fan Chen
- College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Elsayad Kareem
- Advanced Microscopy Facility, Vienna Biocenter Core Facilities, Vienna Biocenter (VBC), Vienna, Austria
| | - Josef M Penninger
- IMBA-Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Benedikt M Kessler
- Target Discovery Institute, Nuffield, Department of Medicine, University of Oxford, Oxford, UK
| | - Vered Raz
- Human Genetics Department, Leiden University Medical Center, Leiden, The Netherlands.
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7
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PABPN1, a Target of p63, Modulates Keratinocyte Differentiation through Regulation of p63α mRNA Translation. J Invest Dermatol 2020; 140:2166-2177.e6. [PMID: 32243883 DOI: 10.1016/j.jid.2020.03.942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/04/2020] [Accepted: 03/09/2020] [Indexed: 01/25/2023]
Abstract
p63 is expressed from two promoters and produces two N-terminal isoforms, TAp63 and ΔNp63. Alternative splicing creates three C-terminal isoforms p63α, p63β, and p63δ, whereas alternative polyadenylation (APA) in coding sequence creates two more C-terminal isoforms p63γ and p63ε. Although several transcription factors have been identified to differentially regulate the N-terminal p63 isoforms, it is unclear how the C-terminal p63 isoforms are regulated. Thus, we determined whether PABPN1, a key regulator of APA, may differentially regulate the C-terminal p63 isoforms. We found that PABPN1 deficiency increases p63γ mRNA through APA in coding sequence. We also found that PABPN1 is necessary for p63α translation by modulating the binding of translation initiation factors eIF4E and eIF4G to p63α mRNA. Moreover, we found that the p53 family, especially p63α, regulates PABPN1 transcription, suggesting that the mutual regulation between p63 and PABPN1 forms a feedback loop. Furthermore, we found that PABPN1 deficiency inhibits keratinocyte cell growth, which can be rescued by ectopic ΔNp63α. Finally, we found that PABPN1 controls the terminal differentiation of HaCaT keratinocytes by modulating ΔNp63α expression. Taken together, our findings suggest that PABPN1 is a key regulator of the C-terminal p63 isoforms through APA in coding sequence and mRNA translation and that the p63-PABPN1 loop modulates p63 activity and the APA landscape.
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