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Reilly A, Chehade L, Kothary R. Curing SMA: Are we there yet? Gene Ther 2023; 30:8-17. [PMID: 35614235 DOI: 10.1038/s41434-022-00349-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/04/2022] [Accepted: 05/12/2022] [Indexed: 11/09/2022]
Abstract
Loss or deletion of survival motor neuron 1 gene (SMN1) is causative for a severe and devastating neuromuscular disease, Spinal Muscular Atrophy (SMA). SMN1 produces SMN, a ubiquitously expressed protein, that is essential for the development and survival of motor neurons. Major advances and developments in SMA therapeutics are shifting the natural history of the disease. With three relatively new available therapies, nusinersen (Spinraza), onasemnogene abeparvovec (Zolgensma), and risdiplam (Evrysdi), patients survive longer and have improved outcomes. However, patients and families continue to face many challenges associated with use of these therapies, including poor treatment response and a variability in the benefits to those that do respond, suggesting that the quest for the SMA cure is not over. In this review, we discuss the current therapies, their limitations, and highlight necessary gaps that need to be addressed to guarantee the best outcomes for SMA patients.
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Affiliation(s)
- Aoife Reilly
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Lucia Chehade
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.,Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada. .,Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada. .,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada. .,Department of Medicine, University of Ottawa, Ottawa, ON, Canada.
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Torroba B, Macabuag N, Haisma EM, O'Neill A, Herva ME, Redis RS, Templin MV, Black LE, Fischer DF. RNA-based drug discovery for spinal muscular atrophy: a story of small molecules and antisense oligonucleotides. Expert Opin Drug Discov 2023; 18:181-192. [PMID: 36408582 DOI: 10.1080/17460441.2022.2149733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Spinal Muscular Atrophy (SMA), the second most prevalent autosomal genetic disease affecting infants, is caused by the lack of SMN1, which encodes a neuron functioning vital protein, SMN. Improving exon 7 splicing in the paralogous gene SMN2, also coding for SMN protein, increases protein production efficiency from SMN2 to overcome the genetic deficit in SMN1. Several molecular mechanisms have been investigated to improve SMN2 functional splicing. AREAS COVERED This manuscript will cover two of the three mechanistically distinct available treatment options for SMA, both targeting the SMN2 splicing mechanism. The first therapeutic, nusinersen (Spinraza®, 2017), is an antisense oligonucleotide (ASO) targeting the splicing inhibitory sequence in the intron downstream of exon 7 from SMN2, thus increasing exon 7 inclusion. The second drug is a small molecule, risdiplam (Evrysdi®, 2021), that enhances the binding of splice factors and also promotes exon 7 inclusion. Both therapies, albeit through different mechanisms, increase full-length SMN protein expression. EXPERT OPINION Nusinersen and risdiplam have directly helped SMA patients and families, but they also herald a sea change in drug development for genetic diseases. This piece aims to draw parallels between both development histories; this may help chart the course for future targeted agents.
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Affiliation(s)
| | | | | | - Amy O'Neill
- Charles River Laboratories, Saffron Walden, UK
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Faravelli I, Riboldi GM, Rinchetti P, Lotti F. The SMN Complex at the Crossroad between RNA Metabolism and Neurodegeneration. Int J Mol Sci 2023; 24:2247. [PMID: 36768569 PMCID: PMC9917330 DOI: 10.3390/ijms24032247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
In the cell, RNA exists and functions in a complex with RNA binding proteins (RBPs) that regulate each step of the RNA life cycle from transcription to degradation. Central to this regulation is the role of several molecular chaperones that ensure the correct interactions between RNA and proteins, while aiding the biogenesis of large RNA-protein complexes (ribonucleoproteins or RNPs). Accurate formation of RNPs is fundamentally important to cellular development and function, and its impairment often leads to disease. The survival motor neuron (SMN) protein exemplifies this biological paradigm. SMN is part of a multi-protein complex essential for the biogenesis of various RNPs that function in RNA metabolism. Mutations leading to SMN deficiency cause the neurodegenerative disease spinal muscular atrophy (SMA). A fundamental question in SMA biology is how selective motor system dysfunction results from reduced levels of the ubiquitously expressed SMN protein. Recent clarification of the central role of the SMN complex in RNA metabolism and a thorough characterization of animal models of SMA have significantly advanced our knowledge of the molecular basis of the disease. Here we review the expanding role of SMN in the regulation of gene expression through its multiple functions in RNP biogenesis. We discuss developments in our understanding of SMN activity as a molecular chaperone of RNPs and how disruption of SMN-dependent RNA pathways can contribute to the SMA phenotype.
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Affiliation(s)
- Irene Faravelli
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giulietta M. Riboldi
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
- The Marlene and Paolo Fresco Institute for Parkinson’s and Movement Disorders, NYU Langone Health, New York, NY 10017, USA
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
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Alves CRR, Ha LL, Yaworski R, Lazzarotto CR, Christie KA, Reilly A, Beauvais A, Doll RM, de la Cruz D, Maguire CA, Swoboda KJ, Tsai SQ, Kothary R, Kleinstiver BP. Base editing as a genetic treatment for spinal muscular atrophy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524978. [PMID: 36711797 PMCID: PMC9882371 DOI: 10.1101/2023.01.20.524978] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disease caused by mutations in the SMN1 gene. Despite the development of various therapies, outcomes can remain suboptimal in SMA infants and the duration of such therapies are uncertain. SMN2 is a paralogous gene that mainly differs from SMN1 by a C•G-to-T•A transition in exon 7, resulting in the skipping of exon 7 in most SMN2 transcripts and production of only low levels of survival motor neuron (SMN) protein. Genome editing technologies targeted to the SMN2 exon 7 mutation could offer a therapeutic strategy to restore SMN protein expression to normal levels irrespective of the patient SMN1 mutation. Here, we optimized a base editing approach to precisely edit SMN2, reverting the exon 7 mutation via an A•T-to-G•C base edit. We tested a range of different adenosine base editors (ABEs) and Cas9 enzymes, resulting in up to 99% intended editing in SMA patient-derived fibroblasts with concomitant increases in SMN2 exon 7 transcript expression and SMN protein levels. We generated and characterized ABEs fused to high-fidelity Cas9 variants which reduced potential off-target editing. Delivery of these optimized ABEs via dual adeno-associated virus (AAV) vectors resulted in precise SMN2 editing in vivo in an SMA mouse model. This base editing approach to correct SMN2 should provide a long-lasting genetic treatment for SMA with advantages compared to current nucleic acid, small molecule, or exogenous gene replacement therapies. More broadly, our work highlights the potential of PAMless SpRY base editors to install edits efficiently and safely.
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Affiliation(s)
- Christiano R. R. Alves
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Leillani L. Ha
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Rebecca Yaworski
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
- Centre for Neuromuscular Disease, University of Ottawa, ON, Canada
| | - Cicera R. Lazzarotto
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Kathleen A. Christie
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Aoife Reilly
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
- Centre for Neuromuscular Disease, University of Ottawa, ON, Canada
| | - Ariane Beauvais
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
- Centre for Neuromuscular Disease, University of Ottawa, ON, Canada
| | - Roman M. Doll
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
- Molecular Biosciences/Cancer Biology Program, Heidelberg University and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Demitri de la Cruz
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Casey A. Maguire
- Molecular Neurogenetics Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Kathryn J. Swoboda
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Shengdar Q. Tsai
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, ON, Canada
- Centre for Neuromuscular Disease, University of Ottawa, ON, Canada
- Department of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Benjamin P. Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
- Department of Pathology, Harvard Medical School, Boston, MA, USA
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Gelsemine relieves the neuropathic pain by down-regulating DPP4 level in rats. Neurosci Lett 2023; 792:136961. [PMID: 36370955 DOI: 10.1016/j.neulet.2022.136961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND Based on the previous findings on the relieving role of gelsemine in neuropathic pain, this research aims to further investigate the relevant regulatory mechanism. METHODS Targets of gelsemine were predicted using SwissTargetPrediction. The peripheral neuropathic pain rat model was established by ligating spinal nerves, and then gelsemine (10 μg for one day) or dipeptidyl peptidase 4 (DPP4) oligonucleotides (5 μg/day, for 7 days) was injected into intrathecal bolus of rats. The mechanical threshold (0, 1, 2, 4 h after the last injection) was examined to evaluate the mechanical allodynia of rats. After the mechanical threshold measurement, the rats were anesthetized with isoflurane and then sacrificed by cervical dislocation. IBA1- and DPP4-positive cells in the spinal dorsal horn of rats were determined using immunohistochemistry and immunofluorescence assays. The expressions of DPP4, IL-1β and TNF-α in the spinal dorsal horn of rats were measured by Western blot and quantitative real-time PCR. RESULTS DPP4 was one of the targets of gelsemine. Gelsemine could elevate the down-regulated mechanical threshold, and lessen the up-regulated IBA1- and DPP4-positive cells and expressions of DPP4, IL-1β and TNF-α in the spinal dorsal horn of rats with neuropathic pain. DPP4 overexpression reversed the role of gelsemine in neuropathic pain. CONCLUSION Gelsemine relieves neuropathic pain by down-regulating DPP4 level in rats, providing a novel drug candidate and biomarker for neuropathic pain treatment.
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Apostolidi M, Stamatopoulou V. Aberrant splicing in human cancer: An RNA structural code point of view. Front Pharmacol 2023; 14:1137154. [PMID: 36909167 PMCID: PMC9995731 DOI: 10.3389/fphar.2023.1137154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023] Open
Abstract
Alternative splicing represents an essential process that occurs widely in eukaryotes. In humans, most genes undergo alternative splicing to ensure transcriptome and proteome diversity reflecting their functional complexity. Over the last decade, aberrantly spliced transcripts due to mutations in cis- or trans-acting splicing regulators have been tightly associated with cancer development, largely drawing scientific attention. Although a plethora of single proteins, ribonucleoproteins, complexed RNAs, and short RNA sequences have emerged as nodal contributors to the splicing cascade, the role of RNA secondary structures in warranting splicing fidelity has been underestimated. Recent studies have leveraged the establishment of novel high-throughput methodologies and bioinformatic tools to shed light on an additional layer of splicing regulation in the context of RNA structural elements. This short review focuses on the most recent available data on splicing mechanism regulation on the basis of RNA secondary structure, emphasizing the importance of the complex RNA G-quadruplex structures (rG4s), and other specific RNA motifs identified as splicing silencers or enhancers. Moreover, it intends to provide knowledge on newly established techniques that allow the identification of RNA structural elements and highlight the potential to develop new RNA-oriented therapeutic strategies against cancer.
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Affiliation(s)
- Maria Apostolidi
- Agilent Laboratories, Agilent Technologies, Santa Clara, CA, United States
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Rogalska ME, Vafiadaki E, Erpapazoglou Z, Haghighi K, Green L, Mantzoros CS, Hajjar RJ, Tranter M, Karakikes I, Kranias EG, Stillitano F, Kafasla P, Sanoudou D. Isoform changes of action potential regulators in the ventricles of arrhythmogenic phospholamban-R14del humanized mouse hearts. Metabolism 2023; 138:155344. [PMID: 36375644 DOI: 10.1016/j.metabol.2022.155344] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022]
Abstract
Arrhythmogenic cardiomyopathy (ACM) is characterized by life-threatening ventricular arrhythmias and sudden cardiac death and affects hundreds of thousands of patients worldwide. The deletion of Arginine 14 (p.R14del) in the phospholamban (PLN) gene has been implicated in the pathogenesis of ACM. PLN is a key regulator of sarcoplasmic reticulum (SR) Ca2+ cycling and cardiac contractility. Despite global gene and protein expression studies, the molecular mechanisms of PLN-R14del ACM pathogenesis remain unclear. Using a humanized PLN-R14del mouse model and human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs), we investigated the transcriptome-wide mRNA splicing changes associated with the R14del mutation. We identified >200 significant alternative splicing (AS) events and distinct AS profiles were observed in the right (RV) and left (LV) ventricles in PLN-R14del compared to WT mouse hearts. Enrichment analysis of the AS events showed that the most affected biological process was associated with "cardiac cell action potential", specifically in the RV. We found that splicing of 2 key genes, Trpm4 and Camk2d, which encode proteins regulating calcium homeostasis in the heart, were altered in PLN-R14del mouse hearts and human iPSC-CMs. Bioinformatical analysis pointed to the tissue-specific splicing factors Srrm4 and Nova1 as likely upstream regulators of the observed splicing changes in the PLN-R14del cardiomyocytes. Our findings suggest that aberrant splicing may affect Ca2+-homeostasis in the heart, contributing to the increased risk of arrythmogenesis in PLN-R14del ACM.
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Affiliation(s)
- Malgorzata E Rogalska
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Zoi Erpapazoglou
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 16672 Athens, Greece
| | - Kobra Haghighi
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Lisa Green
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA 02215, USA
| | | | - Michael Tranter
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Ioannis Karakikes
- Department of Cardiothoracic Surgery and Cardiovascular Institute, Stanford University School of Medicine, 240 Pasteur Dr, Stanford, CA 94304, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Francesca Stillitano
- Division Heart and Lung, Department of Cardiology, University Medical Center Utrecht, 3584, CX, Utrecht, the Netherlands
| | - Panagiota Kafasla
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 16672 Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece; Clinical Genomics and Pharmacogenomics Unit, 4(th) Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece.
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Day JW, Howell K, Place A, Long K, Rossello J, Kertesz N, Nomikos G. Advances and limitations for the treatment of spinal muscular atrophy. BMC Pediatr 2022; 22:632. [PMID: 36329412 PMCID: PMC9632131 DOI: 10.1186/s12887-022-03671-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 10/16/2022] [Indexed: 11/06/2022] Open
Abstract
Spinal muscular atrophy (5q-SMA; SMA), a genetic neuromuscular condition affecting spinal motor neurons, is caused by defects in both copies of the SMN1 gene that produces survival motor neuron (SMN) protein. The highly homologous SMN2 gene primarily expresses a rapidly degraded isoform of SMN protein that causes anterior horn cell degeneration, progressive motor neuron loss, skeletal muscle atrophy and weakness. Severe cases result in limited mobility and ventilatory insufficiency. Untreated SMA is the leading genetic cause of death in young children. Recently, three therapeutics that increase SMN protein levels in patients with SMA have provided incremental improvements in motor function and developmental milestones and prevented the worsening of SMA symptoms. While the therapeutic approaches with Spinraza®, Zolgensma®, and Evrysdi® have a clinically significant impact, they are not curative. For many patients, there remains a significant disease burden. A potential combination therapy under development for SMA targets myostatin, a negative regulator of muscle mass and strength. Myostatin inhibition in animal models increases muscle mass and function. Apitegromab is an investigational, fully human, monoclonal antibody that specifically binds to proforms of myostatin, promyostatin and latent myostatin, thereby inhibiting myostatin activation. A recently completed phase 2 trial demonstrated the potential clinical benefit of apitegromab by improving or stabilizing motor function in patients with Type 2 and Type 3 SMA and providing positive proof-of-concept for myostatin inhibition as a target for managing SMA. The primary goal of this manuscript is to orient physicians to the evolving landscape of SMA treatment.
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Affiliation(s)
- John W Day
- Department of Neurology, Stanford University, Stanford, CA, USA
| | - Kelly Howell
- Spinal Muscular Atrophy Foundation, New York, NY, USA
| | | | | | - Jose Rossello
- Scholar Rock, Inc, 301 Binney St, Cambridge, MA, USA
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Abstract
PURPOSE OF REVIEW The development of new therapies has brought spinal muscular atrophy (SMA) into the spotlight. However, this was preceded by a long journey - from the first clinical description to the discovery of the genetic cause to molecular mechanisms of RNA and DNA technology. RECENT FINDINGS Since 2016, the antisense oligonucleotide nusinersen has been (FDA) approved for the treatment of SMA, followed by the gene replacement therapy onasemnogene abeparvovec-xioi in 2019 and the small-molecule risdiplam in 2020. These drugs, all targeting upregulation of the SMN protein not only showed remarkable effects in clinical trials but also in real-world settings. SMA has been implemented in newborn screening in many countries around the world. SMN-independent strategies targeting skeletal muscle, for example, may play another therapeutic approach in the future. SUMMARY This review aims to summarize the major clinical and basic science achievements in the field of SMA.
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Affiliation(s)
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Hannover, Germany
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Zilio E, Piano V, Wirth B. Mitochondrial Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2022; 23:ijms231810878. [PMID: 36142791 PMCID: PMC9503857 DOI: 10.3390/ijms231810878] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by recessive mutations in the SMN1 gene, globally affecting ~8-14 newborns per 100,000. The severity of the disease depends on the residual levels of functional survival of motor neuron protein, SMN. SMN is a ubiquitously expressed RNA binding protein involved in a plethora of cellular processes. In this review, we discuss the effects of SMN loss on mitochondrial functions in the neuronal and muscular systems that are the most affected in patients with spinal muscular atrophy. Our aim is to highlight how mitochondrial defects may contribute to disease progression and how restoring mitochondrial functionality may be a promising approach to develop new therapies. We also collected from previous studies a list of transcripts encoding mitochondrial proteins affected in various SMA models. Moreover, we speculate that in adulthood, when motor neurons require only very low SMN levels, the natural deterioration of mitochondria associated with aging may be a crucial triggering factor for adult spinal muscular atrophy, and this requires particular attention for therapeutic strategies.
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Affiliation(s)
- Eleonora Zilio
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Valentina Piano
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (V.P.); (B.W.)
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Sun J, Qiu J, Yang Q, Ju Q, Qu R, Wang X, Wu L, Xing L. Single-cell RNA sequencing reveals dysregulation of spinal cord cell types in a severe spinal muscular atrophy mouse model. PLoS Genet 2022; 18:e1010392. [PMID: 36074806 PMCID: PMC9488758 DOI: 10.1371/journal.pgen.1010392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/20/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022] Open
Abstract
Although spinal muscular atrophy (SMA) is a motor neuron disease caused by the loss of survival of motor neuron (SMN) proteins, there is growing evidence that non-neuronal cells play important roles in SMA pathogenesis. However, transcriptome alterations occurring at the single-cell level in SMA spinal cord remain unknown, preventing us from fully comprehending the role of specific cells. Here, we performed single-cell RNA sequencing of the spinal cord of a severe SMA mouse model, and identified ten cell types as well as their differentially expressed genes. Using CellChat, we found that cellular communication between different cell types in the spinal cord of SMA mice was significantly reduced. A dimensionality reduction analysis revealed 29 cell subtypes and their differentially expressed gene. A subpopulation of vascular fibroblasts showed the most significant change in the SMA spinal cord at the single-cell level. This subpopulation was drastically reduced, possibly causing vascular defects and resulting in widespread protein synthesis and energy metabolism reductions in SMA mice. This study reveals for the first time a single-cell atlas of the spinal cord of mice with severe SMA, and sheds new light on the pathogenesis of SMA.
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Affiliation(s)
- Junjie Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
| | - Jiaying Qiu
- Department of Prenatal Screening and Diagnosis Center, Affiliated Maternity and Child Health Care Hospital of Nantong University, Nantong, China
| | - Qiongxia Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Qianqian Ju
- Laboratory Animal Center, Nantong University, Nantong, China
| | - Ruobing Qu
- Biomedical Polymers Laboratory, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Xu Wang
- Laboratory Animal Center, Nantong University, Nantong, China
| | - Liucheng Wu
- Laboratory Animal Center, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
| | - Lingyan Xing
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
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Yesbek Kaymaz A, Kostel Bal S, Bora G, Talim B, Ozon A, Alikasifoglu A, Topaloglu H, Erdem Yurter H. Alterations in insulin-like growth factor system in spinal muscular atrophy. Muscle Nerve 2022; 66:631-638. [PMID: 36050898 DOI: 10.1002/mus.27715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 08/19/2022] [Accepted: 08/26/2022] [Indexed: 11/10/2022]
Abstract
INTRODUCTION/AIMS Spinal muscular atrophy (SMA) is an inherited neuromuscular disease caused by survival motor neuron (SMN) protein deficiency. Insulin-like growth factor-I (IGF-I) is a myotrophic and neurotrophic factor that has been reported to be dysregulated in in vivo SMA model systems. However, detailed analyses of the IGF-I system in SMA patients are missing. In this study, we analyzed the components of the IGF-I system in serum and archived skeletal muscle biopsies of SMA patients. METHODS Serum IGF-I, IGF binding protein (IGFBP)-3, and IGFBP-5 levels were analyzed in 11 SMA patients and 13 healthy children by immunoradiometric and enzyme-linked immunosorbent assays. The expression of IGF-I, IGF-I receptor, and IGFBP-5 proteins was investigated by immunofluorescence analysis in the archived skeletal muscle biopsies of 9 SMA patients, 6 patients with non-SMA-related neuromuscular disease and atrophic fibers in muscle biopsy, and 4 controls. RESULTS A significant decrease in IGF-I levels (mean ± SD: -1.39 ± 1.46 vs. 0.017 ± 0.83, p = 0.02) and increase in IGFBP-5 levels (mean ± SD: 2358.5 ± 1617.4 ng/mL vs. 1003.4 ± 274.3 ng/mL, p=0.03) were detected in serum samples of SMA patients compared to healthy controls. Increased expression of IGF-I, IGF-I receptor, and IGFBP-5 was detected in skeletal muscle biopsies of SMA patients and non-SMA neuromuscular diseases, indicating atrophy-specific alterations in the pathway. DISCUSSION Our findings suggested that the components of the IGF-I system are altered in SMA patients at both the systemic and tissue-specific levels.
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Affiliation(s)
- Ayse Yesbek Kaymaz
- Department of Medical Biology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Sevgi Kostel Bal
- Department of Pediatrics, Neurology Unit, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Gamze Bora
- Department of Medical Biology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Beril Talim
- Department of Pediatrics, Pediatric Pathology Unit, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Alev Ozon
- Department of Pediatrics, Division of Pediatric Endocrinology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Ayfer Alikasifoglu
- Department of Pediatrics, Division of Pediatric Endocrinology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Haluk Topaloglu
- Department of Pediatrics, Neurology Unit, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Hayat Erdem Yurter
- Department of Medical Biology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
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63
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Detering NT, Schüning T, Hensel N, Claus P. The phospho-landscape of the survival of motoneuron protein (SMN) protein: relevance for spinal muscular atrophy (SMA). Cell Mol Life Sci 2022; 79:497. [PMID: 36006469 PMCID: PMC11071818 DOI: 10.1007/s00018-022-04522-9] [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: 03/21/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of the survival of motoneuron (SMN) Protein leading to preferential degeneration of lower motoneurons in the ventral horn of the spinal cord and brain stem. However, the SMN protein is ubiquitously expressed and there is growing evidence of a multisystem phenotype in SMA. Since a loss of SMN function is critical, it is important to decipher the regulatory mechanisms of SMN function starting on the level of the SMN protein itself. Posttranslational modifications (PTMs) of proteins regulate multiple functions and processes, including activity, cellular trafficking, and stability. Several PTM sites have been identified within the SMN sequence. Here, we map the identified SMN PTMs highlighting phosphorylation as a key regulator affecting localization, stability and functions of SMN. Furthermore, we propose SMN phosphorylation as a crucial factor for intracellular interaction and cellular distribution of SMN. We outline the relevance of phosphorylation of the spinal muscular atrophy (SMA) gene product SMN with regard to basic housekeeping functions of SMN impaired in this neurodegenerative disease. Finally, we compare SMA patient mutations with putative and verified phosphorylation sites. Thus, we emphasize the importance of phosphorylation as a cellular modulator in a clinical perspective as a potential additional target for combinatorial SMA treatment strategies.
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Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Niko Hensel
- Ottawa Hospital Research Institute (OHRI), Ottawa, Canada
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany.
- Center for Systems Neuroscience (ZSN), Hannover, Germany.
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Qiu J, Wu L, Qu R, Jiang T, Bai J, Sheng L, Feng P, Sun J. History of development of the life-saving drug “Nusinersen” in spinal muscular atrophy. Front Cell Neurosci 2022; 16:942976. [PMID: 36035257 PMCID: PMC9414009 DOI: 10.3389/fncel.2022.942976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/20/2022] [Indexed: 11/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder with an incidence of 1/6,000–1/10,000 and is the leading fatal disease among infants. Previously, there was no effective treatment for SMA. The first effective drug, nusinersen, was approved by the US FDA in December 2016, providing hope to SMA patients worldwide. The drug was introduced in the European Union in 2017 and China in 2019 and has so far saved the lives of several patients in most parts of the world. Nusinersen are fixed sequence antisense oligonucleotides with special chemical modifications. The development of nusinersen progressed through major scientific discoveries in medicine, genetics, biology, and other disciplines, wherein several scientists have made substantial contributions. In this article, we will briefly describe the pathogenesis and therapeutic strategies of SMA, summarize the timeline of important scientific findings during the development of nusinersen in a detailed, scientific, and objective manner, and finally discuss the implications of the development of nusinersen for SMA research.
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Affiliation(s)
- Jiaying Qiu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- Department of Prenatal Screening and Diagnosis Center, Affiliated Maternity and Child Health Care Hospital of Nantong University, Nantong, China
| | - Liucheng Wu
- Laboratory Animal Center, Nantong University, Nantong, China
| | - Ruobing Qu
- Biomedical Polymers Laboratory, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Tao Jiang
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Jialin Bai
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Lei Sheng
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Pengchao Feng
- Nanjing Antisense Biopharmaceutical Co., Ltd, Nanjing, China
| | - Junjie Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- *Correspondence: Junjie Sun
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Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in SMN1 (encoding survival motor neuron protein (SMN)). Reduced expression of SMN leads to loss of α-motor neurons, severe muscle weakness and often early death. Standard-of-care recommendations for multidisciplinary supportive care of SMA were established in the past few decades. However, improved understanding of the pathogenetic mechanisms of SMA has led to the development of different therapeutic approaches. Three treatments that increase SMN expression by distinct molecular mechanisms, administration routes and tissue biodistributions have received regulatory approval with others in clinical development. The advent of the new therapies is redefining standards of care as in many countries most patients are treated with one of the new therapies, leading to the identification of emerging new phenotypes of SMA and a renewed characterization of demographics owing to improved patient survival.
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66
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Chehade L, Deguise MO, De Repentigny Y, Yaworski R, Beauvais A, Gagnon S, Hensel N, Kothary R. Suppression of the necroptotic cell death pathways improves survival in Smn2B/− mice. Front Cell Neurosci 2022; 16:972029. [PMID: 35990890 PMCID: PMC9381707 DOI: 10.3389/fncel.2022.972029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a monogenic neuromuscular disease caused by low levels of the Survival Motor Neuron (SMN) protein. Motor neuron degeneration is the central hallmark of the disease. However, the SMN protein is ubiquitously expressed and depletion of the protein in peripheral tissues results in intrinsic disease manifestations, including muscle defects, independent of neurodegeneration. The approved SMN-restoring therapies have led to remarkable clinical improvements in SMA patients. Yet, the presence of a significant number of non-responders stresses the need for complementary therapeutic strategies targeting processes which do not rely solely on restoring SMN. Dysregulated cell death pathways are candidates for SMN-independent pathomechanisms in SMA. Receptor-interacting protein kinase 1 (RIPK1) and RIPK3 have been widely recognized as critical therapeutic targets of necroptosis, an important form of programmed cell death. In addition, Caspase-1 plays a fundamental role in inflammation and cell death. In this study, we evaluate the role of necroptosis, particularly RIPK3 and Caspase-1, in the Smn2B/− mouse model of SMA. We have generated a triple mutant (TKO), the Smn2B/−; Ripk3−/−; Casp1−/− mouse. TKO mice displayed a robust increase in survival and improved motor function compared to Smn2B/− mice. While there was no protection against motor neuron loss or neuromuscular junction pathology, larger muscle fibers were observed in TKO mice compared to Smn2B/− mice. Our study shows that necroptosis modulates survival, motor behavior and muscle fiber size independent of SMN levels and independent of neurodegeneration. Thus, small-molecule inhibitors of necroptosis as a combinatorial approach together with SMN-restoring drugs could be a future strategy for the treatment of SMA.
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Affiliation(s)
- Lucia Chehade
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Marc-Olivier Deguise
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Rebecca Yaworski
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Ariane Beauvais
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Sabrina Gagnon
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Niko Hensel
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Center for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
- Department of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada
- *Correspondence: Rashmi Kothary
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67
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Carlini MJ, Triplett MK, Pellizzoni L. Neuromuscular denervation and deafferentation but not motor neuron death are disease features in the Smn2B/- mouse model of SMA. PLoS One 2022; 17:e0267990. [PMID: 35913953 PMCID: PMC9342749 DOI: 10.1371/journal.pone.0267990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/13/2022] [Indexed: 12/02/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by loss of motor neurons and skeletal muscle atrophy which is caused by ubiquitous deficiency in the survival motor neuron (SMN) protein. Several cellular defects contribute to sensory-motor circuit pathology in SMA mice, but the underlying mechanisms have often been studied in one mouse model without validation in other available models. Here, we used Smn2B/- mice to investigate specific behavioral, morphological, and functional aspects of SMA pathology that we previously characterized in the SMNΔ7 model. Smn2B/- SMA mice on a pure FVB/N background display deficits in body weight gain and muscle strength with onset in the second postnatal week and median survival of 19 days. Morphological analysis revealed severe loss of proprioceptive synapses on the soma of motor neurons and prominent denervation of neuromuscular junctions (NMJs) in axial but not distal muscles. In contrast, no evidence of cell death emerged from analysis of several distinct pools of lumbar motor neurons known to be lost in the disease. Moreover, SMA motor neurons from Smn2B/- mice showed robust nuclear accumulation of p53 but lack of phosphorylation of serine 18 at its amino-terminal, which selectively marks degenerating motor neurons in the SMNΔ7 mouse model. These results indicate that NMJ denervation and deafferentation, but not motor neuron death, are conserved features of SMA pathology in Smn2B/- mice.
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Affiliation(s)
- Maria J. Carlini
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
| | - Marina K. Triplett
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States of America
- * E-mail:
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68
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Grice SJ, Liu JL. Motor defects in a Drosophila model for spinal muscular atrophy result from SMN depletion during early neurogenesis. PLoS Genet 2022; 18:e1010325. [PMID: 35877682 PMCID: PMC9352204 DOI: 10.1371/journal.pgen.1010325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 08/04/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the most common autosomal recessive neurodegenerative disease, and is characterised by spinal motor neuron loss, impaired motor function and, often, premature death. Mutations and deletions in the widely expressed survival motor neuron 1 (SMN1) gene cause SMA; however, the mechanisms underlying the selectivity of motor neuron degeneration are not well understood. Although SMA is degenerative in nature, SMN function during embryonic and early postnatal development appears to be essential for motor neuron survival in animal models and humans. Notwithstanding, how developmental defects contribute to the subversion of postnatal and adult motor function remains elusive. Here, in a Drosophila SMA model, we show that neurodevelopmental defects precede gross locomotor dysfunction in larvae. Furthermore, to specifically address the relevance of SMN during neurogenesis and in neurogenic cell types, we show that SMN knockdown using neuroblast-specific and pan-neuronal drivers, but not differentiated neuron or glial cell drivers, impairs adult motor function. Using targeted knockdown, we further restricted SMN manipulation in neuroblasts to a defined time window. Our aim was to express specifically in the neuronal progenitor cell types that have not formed synapses, and thus a time that precedes neuromuscular junction formation and maturation. By restoring SMN levels in these distinct neuronal population, we partially rescue the larval locomotor defects of Smn mutants. Finally, combinatorial SMN knockdown in immature and mature neurons synergistically enhances the locomotor and survival phenotypes. Our in-vivo study is the first to directly rescue the motor defects of an SMA model by expressing Smn in an identifiable population of Drosophila neuroblasts and developing neurons, highlighting that neuronal sensitivity to SMN loss may arise before synapse establishment and nerve cell maturation. Spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality and leads to the degeneration of the nerves that control muscle function. Loss-of-function mutations in the widely expressed survival motor neuron 1 (SMN1) gene cause SMA, but how low levels of SMN protein cause the neuronal dysfunction is not known. Although SMA is a disease of nerve degeneration, SMN function during nerve cell development may be important, particularly in severe forms of SMA. Nevertheless, how the defects during development and throughout early life contribute to the disease is not well understood. We have previously demonstrated that SMN protein becomes enriched in neuroblasts, which are the cells that divide to produce neurons. In the present study, motor defects observed in our fly model for SMA could be rescued by restoring SMN in neuroblasts alone. In addition, we show that knocking down SMN in healthy flies within the same cell type causes impaired motor function. The present study shows that the manipulation of SMN in a developmentally important cell type can cause motor defects, indicating that a period of abnormal neurodevelopment may contribute to SMA.
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Affiliation(s)
- Stuart J. Grice
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (SJG); , (J-LL)
| | - Ji-Long Liu
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- School of Life Science and Technology, Shanghai, Tech University, Shanghai, China
- * E-mail: (SJG); , (J-LL)
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69
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Bhat VD, Jayaraj J, Babu K. RNA and neuronal function: the importance of post-transcriptional regulation. OXFORD OPEN NEUROSCIENCE 2022; 1:kvac011. [PMID: 38596700 PMCID: PMC10913846 DOI: 10.1093/oons/kvac011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/03/2022] [Accepted: 05/28/2022] [Indexed: 04/11/2024]
Abstract
The brain represents an organ with a particularly high diversity of genes that undergo post-transcriptional gene regulation through multiple mechanisms that affect RNA metabolism and, consequently, brain function. This vast regulatory process in the brain allows for a tight spatiotemporal control over protein expression, a necessary factor due to the unique morphologies of neurons. The numerous mechanisms of post-transcriptional regulation or translational control of gene expression in the brain include alternative splicing, RNA editing, mRNA stability and transport. A large number of trans-elements such as RNA-binding proteins and micro RNAs bind to specific cis-elements on transcripts to dictate the fate of mRNAs including its stability, localization, activation and degradation. Several trans-elements are exemplary regulators of translation, employing multiple cofactors and regulatory machinery so as to influence mRNA fate. Networks of regulatory trans-elements exert control over key neuronal processes such as neurogenesis, synaptic transmission and plasticity. Perturbations in these networks may directly or indirectly cause neuropsychiatric and neurodegenerative disorders. We will be reviewing multiple mechanisms of gene regulation by trans-elements occurring specifically in neurons.
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Affiliation(s)
- Vandita D Bhat
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
| | - Jagannath Jayaraj
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
| | - Kavita Babu
- Centre for Neuroscience, Indian Institute of Science, CV Raman Road, Bangalore 560012, Karnataka, India
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70
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Khayrullina G, Alipio‐Gloria ZA, Deguise M, Gagnon S, Chehade L, Stinson M, Belous N, Bergman EM, Lischka FW, Rotty J, Dalgard CL, Kothary R, Johnson KA, Burnett BG. Survival motor neuron protein deficiency alters microglia reactivity. Glia 2022; 70:1337-1358. [PMID: 35373853 PMCID: PMC9081169 DOI: 10.1002/glia.24177] [Citation(s) in RCA: 3] [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: 11/03/2021] [Revised: 03/20/2022] [Accepted: 03/25/2022] [Indexed: 12/31/2022]
Abstract
Survival motor neuron (SMN) protein deficiency results in loss of alpha motor neurons and subsequent muscle atrophy in patients with spinal muscular atrophy (SMA). Reactive microglia have been reported in SMA mice and depleting microglia rescues the number of proprioceptive synapses, suggesting a role in SMA pathology. Here, we explore the contribution of lymphocytes on microglia reactivity in SMA mice and investigate how SMN deficiency alters the reactive profile of human induced pluripotent stem cell (iPSC)-derived microglia. We show that microglia adopt a reactive morphology in spinal cords of SMA mice. Ablating lymphocytes did not alter the reactive morphology of SMA microglia and did not improve the survival or motor function of SMA mice, indicating limited impact of peripheral immune cells on the SMA phenotype. We found iPSC-derived SMA microglia adopted an amoeboid morphology and displayed a reactive transcriptome profile, increased cell migration, and enhanced phagocytic activity. Importantly, cell morphology and electrophysiological properties of motor neurons were altered when they were incubated with conditioned media from SMA microglia. Together, these data reveal that SMN-deficient microglia adopt a reactive profile and exhibit an exaggerated inflammatory response with potential impact on SMA neuropathology.
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Affiliation(s)
- Guzal Khayrullina
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | | | - Marc‐Olivier Deguise
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanada
- Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Sabrina Gagnon
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
| | - Lucia Chehade
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanada
| | - Matthew Stinson
- Department of BiochemistryUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | - Natalya Belous
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | - Elizabeth M. Bergman
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | - Fritz W. Lischka
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | - Jeremy Rotty
- Department of BiochemistryUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
| | - Clifton L. Dalgard
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
- The American Genome CenterUniformed Services University of the Health SciencesBethesdaMarylandUSA
| | - Rashmi Kothary
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanada
- Department of MedicineUniversity of OttawaOttawaOntarioCanada
| | | | - Barrington G. Burnett
- Department of Anatomy, Physiology, and GeneticsUniformed Services University of the Health Sciences, F. Edward Hebert School of MedicineBethesdaMarylandUSA
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López-Cortés A, Echeverría-Garcés G, Ramos-Medina MJ. Molecular Pathogenesis and New Therapeutic Dimensions for Spinal Muscular Atrophy. BIOLOGY 2022; 11:biology11060894. [PMID: 35741415 PMCID: PMC9219894 DOI: 10.3390/biology11060894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022]
Abstract
The condition known as 5q spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease caused by a deficiency of the ubiquitous protein survival of motor neuron (SMN), which is encoded by the SMN1 and SMN2 genes. It is one of the most common pediatric recessive genetic diseases, and it represents the most common cause of hereditary infant mortality. After decades of intensive basic and clinical research efforts, and improvements in the standard of care, successful therapeutic milestones have been developed, delaying the progression of 5q SMA and increasing patient survival. At the same time, promising data from early-stage clinical trials have indicated that additional therapeutic options are likely to emerge in the near future. Here, we provide updated information on the molecular underpinnings of SMA; we also provide an overview of the rapidly evolving therapeutic landscape for SMA, including SMN-targeted therapies, SMN-independent therapies, and combinational therapies that are likely to be key for the development of treatments that are effective across a patient’s lifespan.
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Affiliation(s)
- Andrés López-Cortés
- Programa de Investigación en Salud Global, Facultad de Ciencias de la Salud, Universidad Internacional SEK, Quito 170302, Ecuador
- Facultad de Medicina, Universidad de Las Américas, Quito 170124, Ecuador
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
- Correspondence:
| | - Gabriela Echeverría-Garcés
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| | - María José Ramos-Medina
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
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72
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Marasco LE, Dujardin G, Sousa-Luís R, Liu YH, Stigliano JN, Nomakuchi T, Proudfoot NJ, Krainer AR, Kornblihtt AR. Counteracting chromatin effects of a splicing-correcting antisense oligonucleotide improves its therapeutic efficacy in spinal muscular atrophy. Cell 2022; 185:2057-2070.e15. [PMID: 35688133 DOI: 10.1016/j.cell.2022.04.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/17/2022] [Accepted: 04/26/2022] [Indexed: 11/19/2022]
Abstract
Spinal muscular atrophy (SMA) is a motor-neuron disease caused by mutations of the SMN1 gene. The human paralog SMN2, whose exon 7 (E7) is predominantly skipped, cannot compensate for the lack of SMN1. Nusinersen is an antisense oligonucleotide (ASO) that upregulates E7 inclusion and SMN protein levels by displacing the splicing repressors hnRNPA1/A2 from their target site in intron 7. We show that by promoting transcriptional elongation, the histone deacetylase inhibitor VPA cooperates with a nusinersen-like ASO to promote E7 inclusion. Surprisingly, the ASO promotes the deployment of the silencing histone mark H3K9me2 on the SMN2 gene, creating a roadblock to RNA polymerase II elongation that inhibits E7 inclusion. By removing the roadblock, VPA counteracts the chromatin effects of the ASO, resulting in higher E7 inclusion without large pleiotropic effects. Combined administration of the nusinersen-like ASO and VPA in SMA mice strongly synergizes SMN expression, growth, survival, and neuromuscular function.
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Affiliation(s)
- Luciano E Marasco
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular and CONICET-UBA, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), 1428 Buenos Aires, Argentina
| | - Gwendal Dujardin
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Rui Sousa-Luís
- Instituto de Medicina Molecular João Lobo Antunes, University of Lisbon, 1649-028 Lisboa, Portugal
| | - Ying Hsiu Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Jose N Stigliano
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular and CONICET-UBA, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), 1428 Buenos Aires, Argentina
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Nick J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Alberto R Kornblihtt
- Universidad de Buenos Aires (UBA), Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular and CONICET-UBA, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), 1428 Buenos Aires, Argentina.
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73
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Khvorova A. Modulation of DNA transcription: The future of ASO therapeutics? Cell 2022; 185:2011-2013. [PMID: 35688130 DOI: 10.1016/j.cell.2022.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/24/2022]
Abstract
In this issue of Cell, Kornblihtt and colleagues report a strategy to improve antisense oligonucleotide spinal muscular atrophy therapy. They discover that the oligonucleotide drug nusinersen, which induces exon inclusion, also promotes repressive chromatin modifications, which in turn work against exon inclusion. Notably, co-administration of histone deacetylase inhibitors counteracted this effect to augment exon inclusion.
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Affiliation(s)
- Anastasia Khvorova
- RNA Therapeutic Institute, UMASS Chan Medical School, Worcester, MA 01581, USA.
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74
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Feng P, Xu Z, Chen J, Liu M, Zhao Y, Wang D, Han L, Wang L, Wan B, Xu X, Li D, Shu Y, Hua Y. Rescue of mis-splicing of a common SLC26A4 mutant associated with sensorineural hearing loss by antisense oligonucleotides. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 28:280-292. [PMID: 35433113 PMCID: PMC8987850 DOI: 10.1016/j.omtn.2022.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 03/18/2022] [Indexed: 11/11/2022]
Abstract
A wide spectrum of SLC26A4 mutations causes Pendred syndrome and enlarged vestibular aqueduct, both associated with sensorineural hearing loss (SNHL). A splice-site mutation, c.919-2A>G (A-2G), which is common in Asian populations, impairs the 3′ splice site of intron 7, resulting in exon 8 skipping during pre-mRNA splicing and a subsequent frameshift that creates a premature termination codon in the following exon. Currently, there is no effective drug treatment for SHNL. For A-2G-triggered SNHL, molecules that correct mis-splicing of the mutant hold promise to treat the disease. Antisense oligonucleotides (ASOs) can promote exon inclusion when targeting specific splicing silencers. Here, we systematically screened a large number of ASOs in a minigene system and identified a few that markedly repressed exon 8 skipping. A lead ASO, which targets a heterogeneous nuclear ribonucleoprotein (hnRNP) A1/A2 intronic splicing silencer (ISS) in intron 8, promoted efficient exon 8 inclusion in cultured peripheral blood mononuclear cells derived from two homozygous patients. In a partially humanized Slc26a4 A-2G mouse model, two subcutaneous injections of the ASO at 160 mg/kg significantly rescued exon 8 splicing in the liver. Our results demonstrate that the ISS-targeting ASO has therapeutic potential to treat genetic hearing loss caused by the A-2G mutation in SLC26A4.
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75
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Zhang L, Abendroth F, Vázquez O. A Chemical Biology Perspective to Therapeutic Regulation of RNA Splicing in Spinal Muscular Atrophy (SMA). ACS Chem Biol 2022; 17:1293-1307. [PMID: 35639849 DOI: 10.1021/acschembio.2c00161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Manipulation of RNA splicing machinery has emerged as a drug modality. Here, we illustrate the potential of this novel paradigm to correct aberrant splicing events focused on the recent therapeutic advances in spinal muscular atrophy (SMA). SMA is an incurable neuromuscular disorder and at present the primary genetic cause of early infant death. This Review summarizes the exciting journey from the first reported SMA cases to the currently approved splicing-switching treatments, i.e., antisense oligonucleotides and small-molecule modifiers. We emphasize both chemical structures and molecular bases for recognition. We briefly discuss the advantages and disadvantages of these treatments and include the remaining challenges and future directions. Finally, we also predict that these success stories will contribute to further therapies for human diseases by RNA-splicing control.
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Affiliation(s)
- Lei Zhang
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Frank Abendroth
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Olalla Vázquez
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), University of Marburg, Karl-von-Frisch-Straße 14, 35043 Marburg, Germany
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76
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Kim JH, Kang JS, Yoo K, Jeong J, Park I, Park JH, Rhee J, Jeon S, Jo YW, Hann SH, Seo M, Moon S, Um SJ, Seong RH, Kong YY. Bap1/SMN axis in Dpp4+ skeletal muscle mesenchymal cells regulates the neuromuscular system. JCI Insight 2022; 7:158380. [PMID: 35603786 PMCID: PMC9220848 DOI: 10.1172/jci.insight.158380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/06/2022] [Indexed: 12/15/2022] Open
Abstract
The survival of motor neuron (SMN) protein is a major component of the pre-mRNA splicing machinery and is required for RNA metabolism. Although SMN has been considered a fundamental gene for the central nervous system, due to its relationship with neuromuscular diseases, such as spinal muscular atrophy, recent studies have also revealed the requirement of SMN in non-neuronal cells in the peripheral regions. Here, we report that the fibro-adipogenic progenitor subpopulation expressing Dpp4 (Dpp4+ FAPs) is required for the neuromuscular system. Furthermore, we also reveal that BRCA1-associated protein-1 (Bap1) is crucial for the stabilization of SMN in FAPs by preventing its ubiquitination-dependent degradation. Inactivation of Bap1 in FAPs decreased SMN levels and accompanied degeneration of the neuromuscular junction, leading to loss of motor neurons and muscle atrophy. Overexpression of the ubiquitination-resistant SMN variant, SMNK186R, in Bap1-null FAPs completely prevented neuromuscular degeneration. In addition, transplantation of Dpp4+ FAPs, but not Dpp4– FAPs, completely rescued neuromuscular defects. Our data reveal the crucial role of Bap1-mediated SMN stabilization in Dpp4+ FAPs for the neuromuscular system and provide the possibility of cell-based therapeutics to treat neuromuscular diseases.
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Affiliation(s)
- Ji-Hoon Kim
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jong-Seol Kang
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Kyusang Yoo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jinguk Jeong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Inkuk Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jong Ho Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Joonwoo Rhee
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Shin Jeon
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Woo Jo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Sang-Hyeon Hann
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Minji Seo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Seungtae Moon
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Soo-Jong Um
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Rho Hyun Seong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Yun Kong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
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77
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Zaharieva IT, Scoto M, Aragon-Gawinska K, Ridout D, Doreste B, Servais L, Muntoni F, Zhou H. Response of plasma microRNAs to nusinersen treatment in patients with SMA. Ann Clin Transl Neurol 2022; 9:1011-1026. [PMID: 35584175 PMCID: PMC9268869 DOI: 10.1002/acn3.51579] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Spinal muscular atrophy (SMA) is a common genetic cause of infant mortality. Nusinersen treatment ameliorates the clinical outcome of SMA, however, some patients respond well, while others have limited response. We investigated microRNAs in blood samples from SMA patients and their response to nusinersen treatment evaluating the potential of circulating microRNAs as biomarkers for SMA. METHODS In a discovery cohort study, microRNA next-generation sequencing was performed in blood samples from SMA patients (SMA type 2, n = 10; SMA type 3, n = 10) and controls (n = 7). The dysregulated microRNAs were further analysed in the therapeutic response cohort comprised of SMA type 1 patients (n = 22) who had received nusinersen treatment, at three time points along the treatment course (baseline, 2 and 6 months of treatment). The levels of the studied microRNAs were correlated to the SMA clinical outcome measures. RESULTS In the discovery cohort, 69 microRNAs were dysregulated between SMA patients and controls. In the therapeutic response cohort, the baseline plasma levels of miR-107, miR-142-5p, miR-335-5p, miR-423-3p, miR-660-5p, miR-378a-3p and miR-23a-3p were associated with the 2 and 6 months response to nusinersen treatment. Furthermore, the levels of miR-107, miR-142-5p, miR-335-5p, miR-423-3p, miR-660-5p and miR-378-3p at 2 months of treatment were associated with the response after 6 months of nusinersen treatment. INTERPRETATION Blood microRNAs could be used as biomarkers to indicate SMA patients' response to nusinersen and to monitor the efficacy of the therapeutic intervention. In addition, some of these microRNAs provide insight into processes involved in SMA that could be exploited as novel therapeutic targets.
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Affiliation(s)
- Irina T Zaharieva
- Developmental Neurosciences Research and Teaching Department, Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Mariacristina Scoto
- Developmental Neurosciences Research and Teaching Department, Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London, London, UK.,Great Ormond Street Hospital, London, UK
| | - Karolina Aragon-Gawinska
- Institute I-Motion, Hôpital Armand Trousseau, Paris, France.,Neurology Department, Medical University of Warsaw, Warsaw, Poland
| | - Deborah Ridout
- Population, Policy & Practice Department, UCL Great Ormond Street Institute of Child Health, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Bruno Doreste
- Developmental Neurosciences Research and Teaching Department, Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Laurent Servais
- Institute I-Motion, Hôpital Armand Trousseau, Paris, France.,Department of Paediatrics, MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK.,Department of Paediatrics, Neuromuscular Reference Center, Centre Hospitalier Universitaire de Liège, Liège, Belgium
| | - Francesco Muntoni
- Developmental Neurosciences Research and Teaching Department, Dubowitz Neuromuscular Centre, Great Ormond Street Institute of Child Health, University College London, London, UK.,Great Ormond Street Hospital, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Haiyan Zhou
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.,Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
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78
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Reilly A, Deguise MO, Beauvais A, Yaworski R, Thebault S, Tessier DR, Tabard-Cossa V, Hensel N, Schneider BL, Kothary R. Central and peripheral delivered AAV9-SMN are both efficient but target different pathomechanisms in a mouse model of spinal muscular atrophy. Gene Ther 2022; 29:544-554. [DOI: 10.1038/s41434-022-00338-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/09/2022]
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79
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Splicing Modulation as a Promising Therapeutic Strategy for Lysosomal Storage Disorders: The Mucopolysaccharidoses Example. Life (Basel) 2022; 12:life12050608. [PMID: 35629276 PMCID: PMC9146820 DOI: 10.3390/life12050608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/07/2022] [Accepted: 04/15/2022] [Indexed: 11/17/2022] Open
Abstract
Over recent decades, the many functions of RNA have become more evident. This molecule has been recognized not only as a carrier of genetic information, but also as a specific and essential regulator of gene expression. Different RNA species have been identified and novel and exciting roles have been unveiled. Quite remarkably, this explosion of novel RNA classes has increased the possibility for new therapeutic strategies that tap into RNA biology. Most of these drugs use nucleic acid analogues and take advantage of complementary base pairing to either mimic or antagonize the function of RNAs. Among the most successful RNA-based drugs are those that act at the pre-mRNA level to modulate or correct aberrant splicing patterns, which are caused by specific pathogenic variants. This approach is particularly tempting for monogenic disorders with associated splicing defects, especially when they are highly frequent among affected patients worldwide or within a specific population. With more than 600 mutations that cause disease affecting the pre-mRNA splicing process, we consider lysosomal storage diseases (LSDs) to be perfect candidates for this type of approach. Here, we introduce the overall rationale and general mechanisms of splicing modulation approaches and highlight the currently marketed formulations, which have been developed for non-lysosomal genetic disorders. We also extensively reviewed the existing preclinical studies on the potential of this sort of therapeutic strategy to recover aberrant splicing and increase enzyme activity in our diseases of interest: the LSDs. Special attention was paid to a particular subgroup of LSDs: the mucopolysaccharidoses (MPSs). By doing this, we hoped to unveil the unique therapeutic potential of the use of this sort of approach for LSDs as a whole.
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80
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Brakemeier S, Stolte B, Kleinschnitz C, Hagenacker T. Treatment of Adult Spinal Muscular Atrophy: Overview and Recent Developments. Curr Pharm Des 2022; 28:892-898. [PMID: 35352647 DOI: 10.2174/1381612828666220329115433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 02/03/2022] [Indexed: 11/22/2022]
Abstract
Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disease leading to progressive and in many cases severe muscle weakness and atrophy in the natural disease course. An increasing number of gene-based treatment options have become available in recent years. Growing knowledge about the underlying genetic mechanisms makes the disease well amenable to this. Over the past few years, many data on new treatments, their mechanisms of action and therapeutic outcomes have been published, reflecting the current dynamics in this field. With the approval of the antisense oligonucleotide nusinersen, the vector-based therapy with onasemnogene abeparvovec and the small molecule splicing modifier risdiplam, three gene therapeutic drugs are available for the treatment of SMA showing improvement in motor function. But in the pivotal studies several relevant parameters have not been addressed. There is a data gap for the treatment outcome of adult individuals with SMA as well as for several other relevant outcome parameters like bulbary or ventilatory function. With increasing treatment options, additional individual therapies have become necessary. Studies on combination therapies or switch of therapy, e.g. the sequential administration of onasemnogen abeparvovec and nusinersen, are necessary. An overview of current developments in the field of therapeutic options for adult SMA is presented. Important characteristics of each therapeutic option will be discussed so that the reader can comprehend underlying pathophysiological mechanisms as well as advantages and disadvantages of each therapy. The focus is on gene-based treatment options, but options beyond this are also addressed.
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Affiliation(s)
- Svenja Brakemeier
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Benjamin Stolte
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Tim Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
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81
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Reprogramming RNA processing: an emerging therapeutic landscape. Trends Pharmacol Sci 2022; 43:437-454. [PMID: 35331569 DOI: 10.1016/j.tips.2022.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/13/2022]
Abstract
The production of a mature mRNA requires coordination of multiple processing steps, which ultimately control its content, localization, and stability. These steps include some of the largest macromolecular machines in the cell, which were, until recently, considered undruggable due to their biological complexity. Building from an expanded understanding of the underlying mechanisms that drive these processes, a new wave of therapeutics is seeking to target RNA processing. With a focus on impacting gene regulation at the RNA level, such modalities offer potential for sequence-specific resolution in drug design. Here, we review our current understanding of RNA-processing events and their role in gene regulation, with a focus on the therapeutic opportunities that have emerged within this landscape.
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82
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Bersani M, Rizzuti M, Pagliari E, Garbellini M, Saccomanno D, Moulton HM, Bresolin N, Comi GP, Corti S, Nizzardo M. Cell-penetrating peptide-conjugated Morpholino rescues SMA in a symptomatic preclinical model. Mol Ther 2022; 30:1288-1299. [PMID: 34808387 PMCID: PMC8899506 DOI: 10.1016/j.ymthe.2021.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 07/07/2021] [Accepted: 11/16/2021] [Indexed: 12/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a motor neuron disease and the leading genetic cause of infant mortality. Recently approved SMA therapies have transformed a deadly disease into a survivable one, but these compounds show a wide spectrum of clinical response and effective rescue only in the early stages of the disease. Therefore, safe, symptomatic-suitable, non-invasive treatments with high clinical impact across different phenotypes are urgently needed. We conjugated antisense oligonucleotides with Morpholino (MO) chemistry, which increase SMN protein levels, to cell-penetrating peptides (CPPs) for better cellular distribution. Systemically administered MOs linked to r6 and (RXRRBR)2XB peptides crossed the blood-brain barrier and increased SMN protein levels remarkably, causing striking improvement of survival, neuromuscular function, and neuropathology, even in symptomatic SMA animals. Our study demonstrates that MO-CPP conjugates can significantly expand the therapeutic window through minimally invasive systemic administration, opening the path for clinical applications of this strategy.
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Affiliation(s)
- Margherita Bersani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Mafalda Rizzuti
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Elisa Pagliari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy
| | - Manuela Garbellini
- Healthcare Professionals Department - Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Domenica Saccomanno
- Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Hong M. Moulton
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy,Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Giacomo P. Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy,Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy,Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Diseases Unit, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Milan, Italy,Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Monica Nizzardo
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.
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83
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Tang Z, Hegde S, Zhao J, Zhu S, Johnson KA, Lorson CL, Wang J. CRISPR-mediated Enzyme Fragment Complementation Assay for Quantification of the Stability of Splice Isoforms. Chembiochem 2022; 23:e202200012. [PMID: 35235240 DOI: 10.1002/cbic.202200012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/22/2022] [Indexed: 11/06/2022]
Abstract
Small-molecule splicing modulators exemplified by an FDA-approved drug, risdiplam, are a new pharmacological modality for regulating the expression and stability of splice isoforms. We report a CRISPR-mediated enzyme fragment complementation (EFC) assay to quantify the splice isoform stability. The EFC assay harnessed a 42 amino acid split of a β-galactosidase (designate α-tag), which could be fused at the termini of the target genes using CRISPR/cas9. The α-tagged splice isoform would be quantified by measuring the enzymatic activity upon complementation with the rest of β-galactosidase. This EFC assay retained all the sequences of introns and exons of the target gene in the native genomic environment that recapitulates the cell biology of the diseases of interest. For a proof-of-concept, we developed a CRISPR-mediated EFC assay targeting the exon 7 of the survival of motor neuron 2 (SMN2) gene. The EFC assay compatible with 384-well plates robustly quantified the splicing modulation activity of small molecules. In this study, we also discovered that a coumarin derivative, compound 4, potently modulate SMN2 splicing at as low as 1.1 nM.
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Affiliation(s)
- Zhichao Tang
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Shalakha Hegde
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Junxing Zhao
- University of Kansas School of Pharmacy, Medicinal Chemistry, UNITED STATES
| | - Shoutian Zhu
- PhenoTarget BioSciences, Inc., Biology, UNITED STATES
| | | | | | - Jingxin Wang
- University of Kansas, Medicinal Chemistry, 2034 Becker Dr, 1050, 66047, Lawrence, UNITED STATES
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84
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Verma SK, Deshmukh V, Thatcher K, Belanger KK, Rhyner A, Meng S, Holcomb R, Bressan M, Martin J, Cooke J, Wythe J, Widen S, Lincoln J, Kuyumcu-Martinez M. RBFOX2 is required for establishing RNA regulatory networks essential for heart development. Nucleic Acids Res 2022; 50:2270-2286. [PMID: 35137168 PMCID: PMC8881802 DOI: 10.1093/nar/gkac055] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/14/2022] [Accepted: 01/25/2022] [Indexed: 12/14/2022] Open
Abstract
Human genetic studies identified a strong association between loss of function mutations in RBFOX2 and hypoplastic left heart syndrome (HLHS). There are currently no Rbfox2 mouse models that recapitulate HLHS. Therefore, it is still unknown how RBFOX2 as an RNA binding protein contributes to heart development. To address this, we conditionally deleted Rbfox2 in embryonic mouse hearts and found profound defects in cardiac chamber and yolk sac vasculature formation. Importantly, our Rbfox2 conditional knockout mouse model recapitulated several molecular and phenotypic features of HLHS. To determine the molecular drivers of these cardiac defects, we performed RNA-sequencing in Rbfox2 mutant hearts and identified dysregulated alternative splicing (AS) networks that affect cell adhesion to extracellular matrix (ECM) mediated by Rho GTPases. We identified two Rho GTPase cycling genes as targets of RBFOX2. Modulating AS of these two genes using antisense oligos led to cell cycle and cell-ECM adhesion defects. Consistently, Rbfox2 mutant hearts displayed cell cycle defects and inability to undergo endocardial-mesenchymal transition, processes dependent on cell-ECM adhesion and that are seen in HLHS. Overall, our work not only revealed that loss of Rbfox2 leads to heart development defects resembling HLHS, but also identified RBFOX2-regulated AS networks that influence cell-ECM communication vital for heart development.
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Affiliation(s)
- Sunil K Verma
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Vaibhav Deshmukh
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kaitlyn Thatcher
- Department of Pediatrics, Medical College of Wisconsin, Division of Pediatric Cardiology, The Herma Heart Institute, Children's WI, Milwaukee, WI 53226, USA
| | - KarryAnne K Belanger
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alexander M Rhyner
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Organ Repair and Renewal, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shu Meng
- Houston Methodist Research Institute, Department of Cardiovascular Sciences, Houston, TX 77030, USA
| | - Richard Joshua Holcomb
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael Bressan
- Department of Cell Biology and Physiology, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC27599, USA
| | - James F Martin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Organ Repair and Renewal, Baylor College of Medicine, Houston, TX 77030, USA
- Cardiomyocyte Renewal Lab;Texas Heart Institute, Houston, TX77030, USA
| | - John P Cooke
- Houston Methodist Research Institute, Department of Cardiovascular Sciences, Houston, TX 77030, USA
| | - Joshua D Wythe
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Organ Repair and Renewal, Baylor College of Medicine, Houston, TX 77030, USA
- Cardiomyocyte Renewal Lab;Texas Heart Institute, Houston, TX77030, USA
| | - Steven G Widen
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Joy Lincoln
- Department of Pediatrics, Medical College of Wisconsin, Division of Pediatric Cardiology, The Herma Heart Institute, Children's WI, Milwaukee, WI 53226, USA
| | - Muge N Kuyumcu-Martinez
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Neuroscience, Cell Biology and Anatomy, Institute for Translational Sciences, University of Texas Medical Branch, 301 University Blvd. Galveston, TX 77555, USA
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85
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Induction of Survival of Motor Neuron (SMN) Protein Deficiency in Spinal Astrocytes by Small Interfering RNA as an In Vitro Model of Spinal Muscular Atrophy. Cells 2022; 11:cells11030558. [PMID: 35159369 PMCID: PMC8834238 DOI: 10.3390/cells11030558] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 02/05/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a motor neuron disorder leading to progressive loss of ventral horn neurons resulting in muscle wasting. Here we investigate the contribution of spinal astrocytes to the pathogenesis of late-onset SMA forms using a mouse model. Furthermore, we generated SMA-like astrocytes using survival of motor neuron (SMN) siRNA transfection techniques. In the SMA mouse model, the activation of spinal astrocytes and the reduction of the inward rectifier potassium channel Kir4.1 and excitatory amino acid transporter 1 (EAAT1) were observed at postnatal day (P) 28, preceding the loss of spinal motor neurons appearing earliest at P42. Using SMA-like astrocytes, we could mimic the modulation of spinal astrocytes of the mouse model in a dish and perform electrophysiological assessments and functional assays. In SMA-like astrocytes, glutamate uptake was diminished due to a reduction in EAAT1. Furthermore, patch-clamp measurements revealed reduced potassium uptake into astrocytes with membrane depolarization. Additionally, exposure of healthy spinal motor neurons to a conditioned medium of SMA-like astrocytes resulted in increased firing frequency. These data demonstrate spinal astrocytes’ crucial role in the late-onset SMA forms’ pathogenesis.
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86
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Dominguez CE, Cunningham D, Venkataramany AS, Chandler DS. Heat increases full-length SMN splicing: promise for splice-augmenting therapies for SMA. Hum Genet 2022; 141:239-256. [PMID: 35088120 DOI: 10.1007/s00439-021-02408-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/30/2021] [Indexed: 11/28/2022]
Abstract
Spinal muscular atrophy (SMA) is a debilitating neurodegenerative pediatric disease characterized by low levels of the survival motor protein (SMN). Humans have two SMN genes that produce identical SMN proteins, but they differ at a key nucleotide in exon 7 that induces differential mRNA splicing. SMN1 primarily produces full-length SMN protein, but due to the spliceosome's inability to efficiently recognize exon 7, SMN2 transcripts are often truncated. SMA occurs primarily through mutations or deletions in the SMN1 gene; therefore, current therapies use antisense oligonucleotides (ASOs) to target exon 7 inclusion in SMN2 mRNA and promote full-length SMN protein production. Here, we explore additional methods that can target SMN splicing and therapeutically increase full-length SMN protein. We demonstrate that in vitro heat treatment of cells increases exon 7 inclusion and relative abundance of full-length SMN2 mRNA and protein, a response that is modulated through the upregulation of the positive splicing factor TRA2 beta. We also observe that HSP90, but not HSP40 or HSP70, in the heat shock response is essential for SMN2 exon 7 splicing under hyperthermic conditions. Finally, we show that pulsatile heat treatments for one hour in vitro and in vivo are effective in increasing full-length SMN2 levels. These findings suggest that timed interval treatments could be a therapeutic alternative for SMA patients who do not respond to current ASO-based therapies or require a unique combination regimen.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Akila S Venkataramany
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.,Medical Scientist Training Program, The Ohio State University, Columbus, OH, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA. .,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA. .,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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87
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Allison RL, Welby E, Khayrullina G, Burnett BG, Ebert AD. Viral mediated knockdown of GATA6 in SMA iPSC-derived astrocytes prevents motor neuron loss and microglial activation. Glia 2022; 70:989-1004. [PMID: 35088910 PMCID: PMC9303278 DOI: 10.1002/glia.24153] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 01/18/2022] [Accepted: 01/18/2022] [Indexed: 12/22/2022]
Abstract
Spinal muscular atrophy (SMA), a pediatric genetic disorder, is characterized by the profound loss of spinal cord motor neurons and subsequent muscle atrophy and death. Although the mechanisms underlying motor neuron loss are not entirely clear, data from our work and others support the idea that glial cells contribute to disease pathology. GATA6, a transcription factor that we have previously shown to be upregulated in SMA astrocytes, is negatively regulated by SMN (survival motor neuron) and can increase the expression of inflammatory regulator NFκB. In this study, we identified upregulated GATA6 as a contributor to increased activation, pro-inflammatory ligand production, and neurotoxicity in spinal-cord patterned astrocytes differentiated from SMA patient induced pluripotent stem cells. Reducing GATA6 expression in SMA astrocytes via lentiviral infection ameliorated these effects to healthy control levels. Additionally, we found that SMA astrocytes contribute to SMA microglial phagocytosis, which was again decreased by lentiviral-mediated knockdown of GATA6. Together these data identify a role of GATA6 in SMA astrocyte pathology and further highlight glia as important targets of therapeutic intervention in SMA.
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Affiliation(s)
- Reilly L Allison
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Emily Welby
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Guzal Khayrullina
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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88
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Restoring SMN Expression: An Overview of the Therapeutic Developments for the Treatment of Spinal Muscular Atrophy. Cells 2022; 11:cells11030417. [PMID: 35159227 PMCID: PMC8834523 DOI: 10.3390/cells11030417] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/14/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder and one of the most common genetic causes of infant death. It is characterized by progressive weakness of the muscles, loss of ambulation, and death from respiratory complications. SMA is caused by the homozygous deletion or mutations in the survival of the motor neuron 1 (SMN1) gene. Humans, however, have a nearly identical copy of SMN1 known as the SMN2 gene. The severity of the disease correlates inversely with the number of SMN2 copies present. SMN2 cannot completely compensate for the loss of SMN1 in SMA patients because it can produce only a fraction of functional SMN protein. SMN protein is ubiquitously expressed in the body and has a variety of roles ranging from assembling the spliceosomal machinery, autophagy, RNA metabolism, signal transduction, cellular homeostasis, DNA repair, and recombination. Motor neurons in the anterior horn of the spinal cord are extremely susceptible to the loss of SMN protein, with the reason still being unclear. Due to the ability of the SMN2 gene to produce small amounts of functional SMN, two FDA-approved treatment strategies, including an antisense oligonucleotide (AON) nusinersen and small-molecule risdiplam, target SMN2 to produce more functional SMN. On the other hand, Onasemnogene abeparvovec (brand name Zolgensma) is an FDA-approved adeno-associated vector 9-mediated gene replacement therapy that can deliver a copy of the human SMN1. In this review, we summarize the SMA etiology, the role of SMN, and discuss the challenges of the therapies that are approved for SMA treatment.
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89
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Jablonka S, Hennlein L, Sendtner M. Therapy development for spinal muscular atrophy: perspectives for muscular dystrophies and neurodegenerative disorders. Neurol Res Pract 2022; 4:2. [PMID: 34983696 PMCID: PMC8725368 DOI: 10.1186/s42466-021-00162-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Major efforts have been made in the last decade to develop and improve therapies for proximal spinal muscular atrophy (SMA). The introduction of Nusinersen/Spinraza™ as an antisense oligonucleotide therapy, Onasemnogene abeparvovec/Zolgensma™ as an AAV9-based gene therapy and Risdiplam/Evrysdi™ as a small molecule modifier of pre-mRNA splicing have set new standards for interference with neurodegeneration. MAIN BODY Therapies for SMA are designed to interfere with the cellular basis of the disease by modifying pre-mRNA splicing and enhancing expression of the Survival Motor Neuron (SMN) protein, which is only expressed at low levels in this disorder. The corresponding strategies also can be applied to other disease mechanisms caused by loss of function or toxic gain of function mutations. The development of therapies for SMA was based on the use of cell culture systems and mouse models, as well as innovative clinical trials that included readouts that had originally been introduced and optimized in preclinical studies. This is summarized in the first part of this review. The second part discusses current developments and perspectives for amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease, as well as the obstacles that need to be overcome to introduce RNA-based therapies and gene therapies for these disorders. CONCLUSION RNA-based therapies offer chances for therapy development of complex neurodegenerative disorders such as amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease. The experiences made with these new drugs for SMA, and also the experiences in AAV gene therapies could help to broaden the spectrum of current approaches to interfere with pathophysiological mechanisms in neurodegeneration.
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Affiliation(s)
- Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
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90
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Yeo CJJ, Simmons Z, De Vivo DC, Darras BT. Ethical Perspectives on Treatment Options with Spinal Muscular Atrophy Patients. Ann Neurol 2022; 91:305-316. [PMID: 34981567 PMCID: PMC9305104 DOI: 10.1002/ana.26299] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/31/2021] [Accepted: 12/31/2021] [Indexed: 11/08/2022]
Abstract
Since 2016, 3 innovative therapies for spinal muscular atrophy (SMA) have changed the face of the disease. Although these therapies often result in remarkable improvements in infants and children, benefits in adults are modest and treatment is not curative. Concerns have been raised about the enormous costs of these medications, the ultimate burden to taxpayers, and the costs to society of withholding treatments and sacrificing or disadvantaging some individuals. Physicians are best positioned to serve our patients by carefully considering the costs, benefits, implications for quality of life (QOL), and the interplay of these factors within the framework of core ethical principles that guide clinical care. ANN NEUROL 2022;91:305–316
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Affiliation(s)
- Crystal J. J. Yeo
- Boston Children’s Hospital, Harvard Medical School Boston MA USA
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen Scotland, UK
- LKC school of Medicine Imperial College London and NTU Singapore
- A*STAR Singapore
- Feinberg School of Medicine, Northwestern University Chicago USA
| | - Zachary Simmons
- Penn State Health Milton S. Hershey Medical Center Hershey PA USA
| | | | - Basil T. Darras
- Boston Children’s Hospital, Harvard Medical School Boston MA USA
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91
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Abstract
In Eukarya, immature mRNA transcripts (pre-mRNA) often contain coding sequences, or exons, interleaved by non-coding sequences, or introns. Introns are removed upon splicing, and further regulation of the retained exons leads to alternatively spliced mRNA. The splicing reaction requires the stepwise assembly of the spliceosome, a macromolecular machine composed of small nuclear ribonucleoproteins (snRNPs). This review focuses on the early stage of spliceosome assembly, when U1 snRNP defines each intron 5’-splice site (5ʹss) in the pre-mRNA. We first introduce the splicing reaction and the impact of alternative splicing on gene expression regulation. Thereafter, we extensively discuss splicing descriptors that influence the 5ʹss selection by U1 snRNP, such as sequence determinants, and interactions mediated by U1-specific proteins or U1 small nuclear RNA (U1 snRNA). We also include examples of diseases that affect the 5ʹss selection by U1 snRNP, and discuss recent therapeutic advances that manipulate U1 snRNP 5ʹss selectivity with antisense oligonucleotides and small-molecule splicing switches.
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Affiliation(s)
- Florian Malard
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Cameron D Mackereth
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Sébastien Campagne
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
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92
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Narayanaswami P, Živković S. Molecular and Genetic Therapies. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00011-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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93
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Chilcott EM, Muiruri EW, Hirst TC, Yáñez-Muñoz RJ. Systematic review and meta-analysis determining the benefits of in vivo genetic therapy in spinal muscular atrophy rodent models. Gene Ther 2022; 29:498-512. [PMID: 34611322 PMCID: PMC9482879 DOI: 10.1038/s41434-021-00292-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/30/2021] [Accepted: 09/12/2021] [Indexed: 01/31/2023]
Abstract
Spinal muscular atrophy (SMA) is a severe childhood neuromuscular disease for which two genetic therapies, Nusinersen (Spinraza, an antisense oligonucleotide), and AVXS-101 (Zolgensma, an adeno-associated viral vector of serotype 9 AAV9), have recently been approved. We investigated the pre-clinical development of SMA genetic therapies in rodent models and whether this can predict clinical efficacy. We have performed a systematic review of relevant publications and extracted median survival and details of experimental design. A random effects meta-analysis was used to estimate and compare efficacy. We stratified by experimental design (type of genetic therapy, mouse model, route and time of administration) and sought any evidence of publication bias. 51 publications were identified containing 155 individual comparisons, comprising 2573 animals in total. Genetic therapies prolonged survival in SMA mouse models by 3.23-fold (95% CI 2.75-3.79) compared to controls. Study design characteristics accounted for significant heterogeneity between studies and greatly affected observed median survival ratios. Some evidence of publication bias was found. These data are consistent with the extended average lifespan of Spinraza- and Zolgensma-treated children in the clinic. Together, these results support that SMA has been particularly amenable to genetic therapy approaches and highlight SMA as a trailblazer for therapeutic development.
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Affiliation(s)
- Ellie M. Chilcott
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK ,Present Address: Institute for Women’s Health, UCL, 86-96 Chenies Mews, London, WC1E 6HX UK
| | - Evalyne W. Muiruri
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK
| | - Theodore C. Hirst
- grid.416232.00000 0004 0399 1866Department of Neurosurgery, Royal Victoria Hospital, Belfast, BT12 6BA UK
| | - Rafael J. Yáñez-Muñoz
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK
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94
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Zhou H. Design of Bifunctional Antisense Oligonucleotides for Exon Inclusion. Methods Mol Biol 2022; 2434:53-62. [PMID: 35213009 PMCID: PMC9703293 DOI: 10.1007/978-1-0716-2010-6_3] [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] [Indexed: 06/14/2023]
Abstract
Bifunctional antisense oligonucleotide (AON) is a specially designed AON to regulate pre-messenger RNA (pre-mRNA) splicing of a target gene. It is composed of two domains. The antisense domain contains sequences complementary to the target gene. The tail domain includes RNA sequences that recruit RNA binding proteins which may act positively or negatively in pre-mRNA splicing. This approach can be designed as targeted oligonucleotide enhancers of splicing, named TOES, for exon inclusion; or as targeted oligonucleotide silencers of splicing, named TOSS, for exon skipping. Here, we provide detailed methods for the design of TOES for exon inclusion, using SMN2 exon 7 splicing as an example. A number of annealing sites and the tail sequences previously published are listed. We also present methodology of assessing the effects of TOES on exon inclusion in fibroblasts cultured from a SMA patient. The effects of TOES on SMN2 exon 7 splicing were validated at RNA level by PCR and quantitative real-time PCR, and at protein level by western blotting.
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Affiliation(s)
- Haiyan Zhou
- Genetic and Genomics Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.
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95
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Abstract
Targeting of pre-mRNA splicing has yielded a rich variety of strategies for altering gene expression as a treatment for disease. The search for therapeutics that can modulate splicing has been dominated by antisense oligonucleotides (ASOs) and small molecule compounds, with each platform achieving remarkably effective results in the clinic. The success of RNA-targeting drugs has led to the exploration of new strategies to expand the repertoire of this type of therapeutic. Here, we discuss some of the more common causes of faulty gene expression and provide examples of approaches that have been developed to target and correct these defects for therapeutic value.
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Affiliation(s)
- Jessica L Centa
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
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96
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Jeong S, Widengren J, Lee JC. Fluorescent Probes for STED Optical Nanoscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 12:21. [PMID: 35009972 PMCID: PMC8746377 DOI: 10.3390/nano12010021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Progress in developing fluorescent probes, such as fluorescent proteins, organic dyes, and fluorescent nanoparticles, is inseparable from the advancement in optical fluorescence microscopy. Super-resolution microscopy, or optical nanoscopy, overcame the far-field optical resolution limit, known as Abbe's diffraction limit, by taking advantage of the photophysical properties of fluorescent probes. Therefore, fluorescent probes for super-resolution microscopy should meet the new requirements in the probes' photophysical and photochemical properties. STED optical nanoscopy achieves super-resolution by depleting excited fluorophores at the periphery of an excitation laser beam using a depletion beam with a hollow core. An ideal fluorescent probe for STED nanoscopy must meet specific photophysical and photochemical properties, including high photostability, depletability at the depletion wavelength, low adverse excitability, and biocompatibility. This review introduces the requirements of fluorescent probes for STED nanoscopy and discusses the recent progress in the development of fluorescent probes, such as fluorescent proteins, organic dyes, and fluorescent nanoparticles, for the STED nanoscopy. The strengths and the limitations of the fluorescent probes are analyzed in detail.
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Affiliation(s)
- Sejoo Jeong
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology, Daegu 42988, Korea;
| | - Jerker Widengren
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology (KTH), Stockholm 10691, Sweden;
| | - Jong-Chan Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology, Daegu 42988, Korea;
- New Biology Research Center, Daegu Gyeongbuk Institute of Science & Technology, Daegu 42988, Korea
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97
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Wang J, Bai J, OuYang S, Wang H, Jin Y, Peng X, Ge X, Jiao H, Zou J, He C, Xiao P, Song F, Qu Y. Antisense oligonucleotides targeting the SMN2 promoter region enhance SMN2 expression in spinal muscular atrophy cell lines and mouse model. Hum Mol Genet 2021; 31:1635-1650. [PMID: 34888619 DOI: 10.1093/hmg/ddab350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/17/2021] [Accepted: 12/02/2021] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by homozygous deletions or mutations in survival motor neuron gene 1 (SMN1). Currently, the primary therapeutic strategy for SMA is to increase the level of SMN via correcting SMN2 splicing (nusinersen and risdiplam). However, some patients with SMA do not respond to such treatments, thereby warranting a need to develop new therapeutic strategies. We have previously reported that SMN2 expression is epigenetically regulated by DNA methylation levels of the SMN2 promoter region. In the present study, we determined that methyl-CpG-binding protein 2 (MeCP2) may bind to this critical promoter region (nt-167 to 43). Antisense oligonucleotides (ASO-P1 and ASO-P2) were designed to target the key methylation sites in the SMN2 promoter region, which enhanced the overall transcription and functional protein expression levels in the SMA cell lines. These results were similar to those observed in nusinersen-treated SMA cells. Moreover, a combined treatment of ASO-P1 and ASO-NUS in SMA cell lines further increases fl-SMN2 transcript and SMN protein levels. The delivery of ASO-P1 to the central nervous system of severe SMA mice corrected the molecular, pathological, and functional phenotypes of this disease and increased survival rates. Our findings suggest that the key methylation regions in the SMN2 promoter region may be a novel therapeutic target for SMA.
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Affiliation(s)
- Jia Wang
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Jinli Bai
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Shijia OuYang
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Hong Wang
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Yuwei Jin
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Xiaoyin Peng
- Department of Neurology, Children's Hospital Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Xiushan Ge
- Department of Neurology, Children's Hospital Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Hui Jiao
- Department of Neurology, Children's Hospital Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Jizhen Zou
- Department of pathology, Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Cai He
- Department of pathology, Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Ping Xiao
- Department of pathology, Capital Institute of Pediatrics, Beijing 100020, P.R. China
| | - Fang Song
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
| | - Yujin Qu
- Department of Medical Genetics, Capital Institute of Pediatrics, Beijing, 100020, P.R. China
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98
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Cerro-Herreros E, González-Martínez I, Moreno N, Espinosa-Espinosa J, Fernández-Costa JM, Colom-Rodrigo A, Overby SJ, Seoane-Miraz D, Poyatos-García J, Vilchez JJ, López de Munain A, Varela MA, Wood MJ, Pérez-Alonso M, Llamusí B, Artero R. Preclinical characterization of antagomiR-218 as a potential treatment for myotonic dystrophy. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:174-191. [PMID: 34513303 PMCID: PMC8413838 DOI: 10.1016/j.omtn.2021.07.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 07/17/2021] [Indexed: 12/13/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease caused by expansion of unstable CTG repeats in a non-coding region of the DMPK gene. CUG expansions in mutant DMPK transcripts sequester MBNL1 proteins in ribonuclear foci. Depletion of this protein is a primary contributor to disease symptoms such as muscle weakness and atrophy and myotonia, yet upregulation of endogenous MBNL1 levels may compensate for this sequestration. Having previously demonstrated that antisense oligonucleotides against miR-218 boost MBNL1 expression and rescue phenotypes in disease models, here we provide preclinical characterization of an antagomiR-218 molecule using the HSALR mouse model and patient-derived myotubes. In HSALR, antagomiR-218 reached 40–60 pM 2 weeks after injection, rescued molecular and functional phenotypes in a dose- and time-dependent manner, and showed a good toxicity profile after a single subcutaneous administration. In muscle tissue, antagomiR rescued the normal subcellular distribution of Mbnl1 and did not alter the proportion of myonuclei containing CUG foci. In patient-derived cells, antagomiR-218 improved defective fusion and differentiation and rescued up to 34% of the gene expression alterations found in the transcriptome of patient cells. Importantly, miR-218 was found to be upregulated in DM1 muscle biopsies, pinpointing this microRNA (miRNA) as a relevant therapeutic target.
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Affiliation(s)
- Estefanía Cerro-Herreros
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Irene González-Martínez
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Nerea Moreno
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Jorge Espinosa-Espinosa
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Juan M Fernández-Costa
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Anna Colom-Rodrigo
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Sarah J Overby
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - David Seoane-Miraz
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Javier Poyatos-García
- The IISLAFE Health Research Institute, Avenida Fernando Abril Martorell, 106 Torre A 7 planta, 46026 Valencia, Spain.,Neuromuscular Reference Centre ERN EURO-NMD and Neuromuscular Pathology and Ataxia Research Group, Hospital La Fe Health Research Institute, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan J Vilchez
- The IISLAFE Health Research Institute, Avenida Fernando Abril Martorell, 106 Torre A 7 planta, 46026 Valencia, Spain.,Neuromuscular Reference Centre ERN EURO-NMD and Neuromuscular Pathology and Ataxia Research Group, Hospital La Fe Health Research Institute, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Adolfo López de Munain
- Biodonostia Health Research Institute, P° Dr. Beguiristain s/n, 20014 Donostia-San Sebastián, Spain.,Hospital Universitario Donostia-Osakidetza-Departamento de Neurociencias-Universidad del Pais Vasco-CIBERNED
| | - Miguel A Varela
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Matthew J Wood
- Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headley Way, OX3 9DU, Oxford, UK.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, UK
| | - Manuel Pérez-Alonso
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Beatriz Llamusí
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
| | - Rubén Artero
- University Research Institute for Biotechnology and Biomedicine (BIOTECMED), Universidad de Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.,Incliva Biomedical Research Institute, Avenida Menéndez Pelayo 4 acc, 46010 Valencia, Spain
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99
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Liu J, Guo ZN, Yan XL, Yang Y, Huang S. Brain Pathogenesis and Potential Therapeutic Strategies in Myotonic Dystrophy Type 1. Front Aging Neurosci 2021; 13:755392. [PMID: 34867280 PMCID: PMC8634727 DOI: 10.3389/fnagi.2021.755392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 10/20/2021] [Indexed: 12/17/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy that affects multiple systems including the muscle and heart. The mutant CTG expansion at the 3′-UTR of the DMPK gene causes the expression of toxic RNA that aggregate as nuclear foci. The foci then interfere with RNA-binding proteins, affecting hundreds of mis-spliced effector genes, leading to aberrant alternative splicing and loss of effector gene product functions, ultimately resulting in systemic disorders. In recent years, increasing clinical, imaging, and pathological evidence have indicated that DM1, though to a lesser extent, could also be recognized as true brain diseases, with more and more researchers dedicating to develop novel therapeutic tools dealing with it. In this review, we summarize the current advances in the pathogenesis and pathology of central nervous system (CNS) deficits in DM1, intervention measures currently being investigated are also highlighted, aiming to promote novel and cutting-edge therapeutic investigations.
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Affiliation(s)
- Jie Liu
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Zhen-Ni Guo
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Xiu-Li Yan
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
| | - Shuo Huang
- Department of Neurology, Stroke Center & Clinical Trial and Research Center for Stroke, The First Hospital of Jilin University, Changchun, China
- China National Comprehensive Stroke Center, Changchun, China
- Jilin Provincial Key Laboratory of Cerebrovascular Disease, Changchun, China
- *Correspondence: Shuo Huang,
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100
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Kray KM, McGovern VL, Chugh D, Arnold WD, Burghes AHM. Dual SMN inducing therapies can rescue survival and motor unit function in symptomatic ∆7SMA mice. Neurobiol Dis 2021; 159:105488. [PMID: 34425216 PMCID: PMC8502210 DOI: 10.1016/j.nbd.2021.105488] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/06/2021] [Accepted: 08/16/2021] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by survival motor neuron (SMN) protein deficiency which results in motor neuron loss and muscle atrophy. SMA is caused by a mutation or deletion of the survival motor neuron 1 (SMN1) gene and retention of the nearly identical SMN2 gene. SMN2 contains a C to T change in exon 7 that results in exon 7 exclusion from 90% of transcripts. SMN protein lacking exon 7 is unstable and rapidly degraded. The remaining full-length transcripts from SMN2 are insufficient for normal motor neuron function leading to the development of SMA. Three different therapeutic approaches that increase full-length SMN (FL-SMN) protein production are approved for treatment of SMA patients. Studies in both animal models and humans have demonstrated increasing SMN levels prior to onset of symptoms provides the greatest therapeutic benefit. Treatment of SMA, after some motor neuron loss has occurred, is also effective but to a lesser degree. The SMN∆7 mouse model is a well characterized model of severe or type 1 SMA, dying at 14 days of age. Here we treated three groups of ∆7SMA mice starting before, roughly during, and after symptom onset to determine if combining two mechanistically distinct SMN inducing therapies could improve the therapeutic outcome both before and after motor neuron loss. We found, compared with individual therapies, that morpholino antisense oligonucleotide (ASO) directed against ISS-N1 combined with the small molecule compound RG7800 significantly increased FL-SMN transcript and protein production resulting in improved survival and weight of ∆7SMA mice. Moreover, when give late symptomatically, motor unit function was completely rescued with no loss in function at 100 days of age in the dual treatment group. We have therefore shown that this dual therapeutic approach successfully increases SMN protein and rescues motor function in symptomatic ∆7SMA mice.
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Affiliation(s)
- Kaitlyn M Kray
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA.
| | - Vicki L McGovern
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA.
| | - Deepti Chugh
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA
| | - W David Arnold
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA.
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA; Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA.
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