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Tawil R, Wagner KR, Hamel JI, Leung DG, Statland JM, Wang LH, Genge A, Sacconi S, Lochmüller H, Reyes-Leiva D, Diaz-Manera J, Alonso-Perez J, Muelas N, Vilchez JJ, Pestronk A, Gibson S, Goyal NA, Hayward LJ, Johnson N, LoRusso S, Freimer M, Shieh PB, Subramony SH, van Engelen B, Kools J, Leinhard OD, Widholm P, Morabito C, Moxham CM, Cadavid D, Mellion ML, Odueyungbo A, Tracewell WG, Accorsi A, Ronco L, Gould RJ, Shoskes J, Rojas LA, Jiang JG. Safety and efficacy of losmapimod in facioscapulohumeral muscular dystrophy (ReDUX4): a randomised, double-blind, placebo-controlled phase 2b trial. Lancet Neurol 2024; 23:477-486. [PMID: 38631764 DOI: 10.1016/s1474-4422(24)00073-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 04/19/2024]
Abstract
BACKGROUND Facioscapulohumeral muscular dystrophy is a hereditary progressive myopathy caused by aberrant expression of the transcription factor DUX4 in skeletal muscle. No approved disease-modifying treatments are available for this disorder. We aimed to assess the safety and efficacy of losmapimod (a small molecule that inhibits p38α MAPK, a regulator of DUX4 expression, and p38β MAPK) for the treatment of facioscapulohumeral muscular dystrophy. METHODS We did a randomised, double-blind, placebo-controlled phase 2b trial at 17 neurology centres in Canada, France, Spain, and the USA. We included adults aged 18-65 years with type 1 facioscapulohumeral muscular dystrophy (ie, with loss of repression of DUX4 expression, as ascertained by genotyping), a Ricci clinical severity score of 2-4, and at least one skeletal muscle judged using MRI to be suitable for biopsy. Participants were randomly allocated (1:1) to either oral losmapimod (15 mg twice a day) or matching placebo for 48 weeks, via an interactive response technology system. The investigator, study staff, participants, sponsor, primary outcome assessors, and study monitor were masked to the treatment allocation until study closure. The primary endpoint was change from baseline to either week 16 or 36 in DUX4-driven gene expression in skeletal muscle biopsy samples, as measured by quantitative RT-PCR. The primary efficacy analysis was done in all participants who were randomly assigned and who had available data for assessment, according to the modified intention-to-treat principle. Safety and tolerability were assessed as secondary endpoints. This study is registered at ClinicalTrials.gov, number NCT04003974. The phase 2b trial is complete; an open-label extension is ongoing. FINDINGS Between Aug 27, 2019, and Feb 27, 2020, 80 people were enrolled. 40 were randomly allocated to losmapimod and 40 to placebo. 54 (68%) participants were male and 26 (33%) were female, 70 (88%) were White, and mean age was 45·7 (SD 12·5) years. Least squares mean changes from baseline in DUX4-driven gene expression did not differ significantly between the losmapimod (0·83 [SE 0·61]) and placebo (0·40 [0·65]) groups (difference 0·43 [SE 0·56; 95% CI -1·04 to 1·89]; p=0·56). Losmapimod was well tolerated. 29 treatment-emergent adverse events (nine drug-related) were reported in the losmapimod group compared with 23 (two drug-related) in the placebo group. Two participants in the losmapimod group had serious adverse events that were deemed unrelated to losmapimod by the investigators (alcohol poisoning and suicide attempt; postoperative wound infection) compared with none in the placebo group. No treatment discontinuations due to adverse events occurred and no participants died during the study. INTERPRETATION Although losmapimod did not significantly change DUX4-driven gene expression, it was associated with potential improvements in prespecified structural outcomes (muscle fat infiltration), functional outcomes (reachable workspace, a measure of shoulder girdle function), and patient-reported global impression of change compared with placebo. These findings have informed the design and choice of efficacy endpoints for a phase 3 study of losmapimod in adults with facioscapulohumeral muscular dystrophy. FUNDING Fulcrum Therapeutics.
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Affiliation(s)
- Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Kathryn R Wagner
- Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Johanna I Hamel
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Doris G Leung
- Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | - Leo H Wang
- University of Washington, Seattle, WA, USA
| | - Angela Genge
- Montreal Neurological Institute and Hospital, Montreal, QC, Canada
| | - Sabrina Sacconi
- Peripheral Nervous System and Muscle Department, Nice University Hospital and University of Côte d'Azur, Nice, France
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - David Reyes-Leiva
- Institut de Recerca IIB Sant Pau, Hospital Universitari Santa Creu i Sant Pau, Barcelona, Spain
| | - Jordi Diaz-Manera
- Institut de Recerca IIB Sant Pau, Hospital Universitari Santa Creu i Sant Pau, Barcelona, Spain; John Walton Muscular Dystrophy Research Center, Newcastle University, Newcastle, UK
| | - Jorge Alonso-Perez
- Neuromuscular Diseases Unit, Neurology Department, Hospital Universitario Nuestra Señora de Candelaria, Fundación Canaria Instituto de Investigación Sanitaria de Canarias, Santa Cruz de Tenerife, Tenerife, Spain; Neuromuscular Diseases Unit, Neurology Department, Institut d'Investigació Biomèdica Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Nuria Muelas
- Neuromuscular Diseases Unit, Neurology Department, Hospital Universitari i Politecnic La Fe and Neuromuscular Reference Centre, Valencia, Spain; Neuromuscular and Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain; Department of Medicine, University of Valencia, Valencia, Spain
| | - Juan J Vilchez
- Neuromuscular and Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Alan Pestronk
- Washington University in St Louis, St Louis, MO, USA
| | | | | | | | | | | | - Miriam Freimer
- Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Perry B Shieh
- University of California at Los Angeles, Los Angeles, CA, USA
| | - S H Subramony
- University of Florida College of Medicine, Gainesville, FL, USA
| | - Baziel van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Joost Kools
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Olof Dahlqvist Leinhard
- AMRA Medical, Linköping, Sweden; Division of Diagnostics and Specialist Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Per Widholm
- AMRA Medical, Linköping, Sweden; Division of Diagnostics and Specialist Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden; Department of Radiology, Linköping University, Linköping, Sweden
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Andrea ZA, Matteo FY, Alessandra B, Carlo PS. Molecular mechanisms and therapeutic strategies for neuromuscular diseases. Cell Mol Life Sci 2024; 81:198. [PMID: 38678519 PMCID: PMC11056344 DOI: 10.1007/s00018-024-05229-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/14/2024] [Accepted: 04/07/2024] [Indexed: 05/01/2024]
Abstract
Neuromuscular diseases encompass a heterogeneous array of disorders characterized by varying onset ages, clinical presentations, severity, and progression. While these conditions can stem from acquired or inherited causes, this review specifically focuses on disorders arising from genetic abnormalities, excluding metabolic conditions. The pathogenic defect may primarily affect the anterior horn cells, the axonal or myelin component of peripheral nerves, the neuromuscular junction, or skeletal and/or cardiac muscles. While inherited neuromuscular disorders have been historically deemed not treatable, the advent of gene-based and molecular therapies is reshaping the treatment landscape for this group of condition. With the caveat that many products still fail to translate the positive results obtained in pre-clinical models to humans, both the technological development (e.g., implementation of tissue-specific vectors) as well as advances on the knowledge of pathogenetic mechanisms form a collective foundation for potentially curative approaches to these debilitating conditions. This review delineates the current panorama of therapies targeting the most prevalent forms of inherited neuromuscular diseases, emphasizing approved treatments and those already undergoing human testing, offering insights into the state-of-the-art interventions.
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Affiliation(s)
- Zambon Alberto Andrea
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Falzone Yuri Matteo
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
| | - Bolino Alessandra
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Previtali Stefano Carlo
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy.
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy.
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Rawls A, Diviak BK, Smith CI, Severson GW, Acosta SA, Wilson-Rawls J. Pharmacotherapeutic Approaches to Treatment of Muscular Dystrophies. Biomolecules 2023; 13:1536. [PMID: 37892218 PMCID: PMC10605463 DOI: 10.3390/biom13101536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Muscular dystrophies are a heterogeneous group of genetic muscle-wasting disorders that are subdivided based on the region of the body impacted by muscle weakness as well as the functional activity of the underlying genetic mutations. A common feature of the pathophysiology of muscular dystrophies is chronic inflammation associated with the replacement of muscle mass with fibrotic scarring. With the progression of these disorders, many patients suffer cardiomyopathies with fibrosis of the cardiac tissue. Anti-inflammatory glucocorticoids represent the standard of care for Duchenne muscular dystrophy, the most common muscular dystrophy worldwide; however, long-term exposure to glucocorticoids results in highly adverse side effects, limiting their use. Thus, it is important to develop new pharmacotherapeutic approaches to limit inflammation and fibrosis to reduce muscle damage and promote repair. Here, we examine the pathophysiology, genetic background, and emerging therapeutic strategies for muscular dystrophies.
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Affiliation(s)
- Alan Rawls
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
| | - Bridget K. Diviak
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
- Molecular and Cellular Biology Graduate Program, School of Life Sciences, Tempe, AZ 85287 4501, USA
| | - Cameron I. Smith
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
- Molecular and Cellular Biology Graduate Program, School of Life Sciences, Tempe, AZ 85287 4501, USA
| | - Grant W. Severson
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
- Molecular and Cellular Biology Graduate Program, School of Life Sciences, Tempe, AZ 85287 4501, USA
| | - Sofia A. Acosta
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
- Molecular and Cellular Biology Graduate Program, School of Life Sciences, Tempe, AZ 85287 4501, USA
| | - Jeanne Wilson-Rawls
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA; (B.K.D.); (C.I.S.); (G.W.S.); (S.A.A.)
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Sarsons CD, Gilham D, Tsujikawa LM, Wasiak S, Fu L, Rakai BD, Stotz SC, Carestia A, Sweeney M, Kulikowski E. Apabetalone, a Clinical-Stage, Selective BET Inhibitor, Opposes DUX4 Target Gene Expression in Primary Human FSHD Muscle Cells. Biomedicines 2023; 11:2683. [PMID: 37893058 PMCID: PMC10604783 DOI: 10.3390/biomedicines11102683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/22/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Facioscapulohumeral dystrophy (FSHD) is a muscle disease caused by inappropriate expression of the double homeobox 4 (DUX4) gene in skeletal muscle, and its downstream activation of pro-apoptotic transcriptional programs. Inhibitors of DUX4 expression have the potential to treat FSHD. Apabetalone is a clinical-stage bromodomain and extra-terminal (BET) inhibitor, selective for the second bromodomain on BET proteins. Using primary human skeletal muscle cells from FSHD type 1 patients, we evaluated apabetalone for its ability to counter DUX4's deleterious effects and compared it with the pan-BET inhibitor JQ1, and the p38 MAPK inhibitor-and DUX4 transcriptional repressor-losmapimod. We applied RNA-sequencing and bioinformatic analysis to detect treatment-associated impacts on the transcriptome of these cells. Apabetalone inhibited the expression of DUX4 downstream markers, reversing hallmarks of FSHD gene expression in differentiated muscle cells. JQ1, but not apabetalone, was found to induce apoptosis. While both BET inhibitors modestly impacted differentiation marker expression, they did not affect myotube fusion. Losmapimod also reduced expression of DUX4 target genes but differed in its impact on FSHD-associated pathways. These findings demonstrate that apabetalone inhibits DUX4 target gene expression and reverses transcriptional programs that contribute to FSHD pathology, making this drug a promising candidate therapeutic for FSHD.
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Affiliation(s)
| | - Dean Gilham
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Laura M. Tsujikawa
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Sylwia Wasiak
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Li Fu
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Brooke D. Rakai
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Stephanie C. Stotz
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Agostina Carestia
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
| | - Michael Sweeney
- Resverlogix Corp., 535 Mission St., 14th Floor, San Francisco, CA 94105, USA
| | - Ewelina Kulikowski
- Resverlogix Corp., 300, 4820 Richard Road SW, Calgary, AB T3E 6L1, Canada
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5
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Duranti E, Villa C. Influence of DUX4 Expression in Facioscapulohumeral Muscular Dystrophy and Possible Treatments. Int J Mol Sci 2023; 24:ijms24119503. [PMID: 37298453 DOI: 10.3390/ijms24119503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/23/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) represents the third most common form of muscular dystrophy and is characterized by muscle weakness and atrophy. FSHD is caused by the altered expression of the transcription factor double homeobox 4 (DUX4), which is involved in several significantly altered pathways required for myogenesis and muscle regeneration. While DUX4 is normally silenced in the majority of somatic tissues in healthy individuals, its epigenetic de-repression has been linked to FSHD, resulting in DUX4 aberrant expression and cytotoxicity in skeletal muscle cells. Understanding how DUX4 is regulated and functions could provide useful information not only to further understand FSHD pathogenesis, but also to develop therapeutic approaches for this disorder. Therefore, this review discusses the role of DUX4 in FSHD by examining the possible molecular mechanisms underlying the disease as well as novel pharmacological strategies targeting DUX4 aberrant expression.
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Affiliation(s)
- Elisa Duranti
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
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6
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Ziegler A, Walter MC, Schoser BE. [Molecular therapies: present and future in neuromuscular diseases]. DER NERVENARZT 2023:10.1007/s00115-023-01495-3. [PMID: 37221259 DOI: 10.1007/s00115-023-01495-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/14/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND The possibilities in the field of molecular therapies of neuromuscular diseases have rapidly developed in recent years. First compounds are already available in clinical practice and numerous other substances are in advanced phases of clinical trials. This article gives an exemplary overview of the current state of clinical research in molecular therapies of neuromuscular diseases. It also gives a view into the near future of the clinical application, including the challenges. DISCUSSION Using Duchenne muscular dystrophy (DMD) and myotubular myopathy as examples, the principles of gene addition in monogenetic skeletal muscle diseases, which are already manifested in childhood are described. In addition to initial successes, the challenges and setbacks hindering the approval and regular clinical application of further compounds are demonstrated. Furthermore, the state of current clinical research in Becker-Kiener muscular dystrophy (BMD) and the numerous forms of limb-girdle muscular dystrophy (LGMD) are summarized. Numerous new therapeutic approaches and a corresponding outlook are also shown for facioscapulohumeral muscular dystrophy (FSHD), Pompe disease, and myotonic dystrophy. CONCLUSION Clinical research in the field of molecular therapy of neuromuscular diseases is one of the pacesetters of modern precision medicine; however, challenges need to be seen, jointly addressed and overcome in the future.
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Affiliation(s)
- Andreas Ziegler
- Zentrum für Kinder- und Jugendmedizin Heidelberg, Sektion Neuropädiatrie und Stoffwechselmedizin, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Deutschland.
| | - Maggie C Walter
- Friedrich-Baur-Institut an der Neurologischen Klinik und Poliklinik, Universitätsklinikum München, LMU München, Ziemssenstr. 1, 80336, München, Deutschland
| | - Benedikt E Schoser
- Friedrich-Baur-Institut an der Neurologischen Klinik und Poliklinik, Universitätsklinikum München, LMU München, Ziemssenstr. 1, 80336, München, Deutschland
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7
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Inoue K, Bostan H, Browne MR, Bevis OF, Bortner CD, Moore SA, Stence AA, Martin NP, Chen SH, Burkholder AB, Li JL, Shaw ND. DUX4 double whammy: The transcription factor that causes a rare muscular dystrophy also kills the precursors of the human nose. SCIENCE ADVANCES 2023; 9:eabq7744. [PMID: 36800423 PMCID: PMC9937577 DOI: 10.1126/sciadv.abq7744] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 01/12/2023] [Indexed: 05/19/2023]
Abstract
SMCHD1 mutations cause congenital arhinia (absent nose) and a muscular dystrophy called FSHD2. In FSHD2, loss of SMCHD1 repressive activity causes expression of double homeobox 4 (DUX4) in muscle tissue, where it is toxic. Studies of arhinia patients suggest a primary defect in nasal placode cells (human nose progenitors). Here, we show that upon SMCHD1 ablation, DUX4 becomes derepressed in H9 human embryonic stem cells (hESCs) as they differentiate toward a placode cell fate, triggering cell death. Arhinia and FSHD2 patient-derived induced pluripotent stem cells (iPSCs) express DUX4 when converted to placode cells and demonstrate variable degrees of cell death, suggesting an environmental disease modifier. HSV-1 may be one such modifier as herpesvirus infection amplifies DUX4 expression in SMCHD1 KO hESC and patient iPSC. These studies suggest that arhinia, like FSHD2, is due to compromised SMCHD1 repressive activity in a cell-specific context and provide evidence for an environmental modifier.
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Affiliation(s)
- Kaoru Inoue
- Pediatric Neuroendocrinology Group, Clinical Research Branch, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, USA
| | - Hamed Bostan
- Integrative Bioinformatics, NIEHS, Research Triangle Park, NC, USA
| | - MaKenna R. Browne
- Pediatric Neuroendocrinology Group, Clinical Research Branch, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, USA
| | - Owen F. Bevis
- Pediatric Neuroendocrinology Group, Clinical Research Branch, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, USA
| | - Carl D. Bortner
- Signal Transduction Laboratory, NIEHS, Research Triangle Park, NC, USA
| | - Steven A. Moore
- Department of Pathology, University of Iowa Carver College of Medicine and Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, Iowa City, IA, USA
| | - Aaron A. Stence
- University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | | | - Shih-Heng Chen
- Viral Vector Core, NIEHS, Research Triangle Park, NC, USA
| | | | - Jian-Liang Li
- Integrative Bioinformatics, NIEHS, Research Triangle Park, NC, USA
| | - Natalie D. Shaw
- Pediatric Neuroendocrinology Group, Clinical Research Branch, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, USA
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Tihaya MS, Mul K, Balog J, de Greef JC, Tapscott SJ, Tawil R, Statland JM, van der Maarel SM. Facioscapulohumeral muscular dystrophy: the road to targeted therapies. Nat Rev Neurol 2023; 19:91-108. [PMID: 36627512 DOI: 10.1038/s41582-022-00762-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2022] [Indexed: 01/11/2023]
Abstract
Advances in the molecular understanding of facioscapulohumeral muscular dystrophy (FSHD) have revealed that FSHD results from epigenetic de-repression of the DUX4 gene in skeletal muscle, which encodes a transcription factor that is active in early embryonic development but is normally silenced in almost all somatic tissues. These advances also led to the identification of targets for disease-altering therapies for FSHD, as well as an improved understanding of the molecular mechanism of the disease and factors that influence its progression. Together, these developments led the FSHD research community to shift its focus towards the development of disease-modifying treatments for FSHD. This Review presents advances in the molecular and clinical understanding of FSHD, discusses the potential targeted therapies that are currently being explored, some of which are already in clinical trials, and describes progress in the development of FSHD-specific outcome measures and assessment tools for use in future clinical trials.
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Affiliation(s)
- Mara S Tihaya
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Karlien Mul
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Judit Balog
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jessica C de Greef
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stephen J Tapscott
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Rabi Tawil
- Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jeffrey M Statland
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
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Schoser B. Molekulare Therapien erblicher Myopathien im Erwachsenenalter
– eine kursive Rundschau. FORTSCHRITTE DER NEUROLOGIE · PSYCHIATRIE 2022; 91:164-168. [PMID: 36347473 DOI: 10.1055/a-1953-7261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
ZusammenfassungUnterschiedliche Formen der molekularen Therapie sind zu einer neuen
Möglichkeit in der Präzisionsbehandlung erblicher
neuromuskulärer Erkrankungen geworden. Dieser kursive Überblick
über die molekularen Therapien bei hereditären Myopathien wird
sich auf ausgewählte aktuelle Phase 1 bis 3 Studien zu häufigen
hereditären Myopathien im Erwachsenenalter wie die Dystrophinopathie
Becker-Kiener, die Fazioskapulohumerale Muskeldystrophie, Calpainopathie, und
die Dysferlinopathie fokussieren. Die Therapieoptionen zum Morbus Pompe dienen
als Beispiel für die hereditären metabolischen Myopathien.
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Affiliation(s)
- Benedikt Schoser
- Friedrich-Baur-Institut, Neurologische Klinik,
Ludwig-Maximilians-Universität München, München,
Germany
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10
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Brennan CM, Hill AS, St. Andre M, Li X, Madeti V, Breitkopf S, Garren S, Xue L, Gilbert T, Hadjipanayis A, Monetti M, Emerson CP, Moccia R, Owens J, Christoforou N. DUX4 expression activates JNK and p38 MAP kinases in myoblasts. Dis Model Mech 2022; 15:dmm049516. [PMID: 36196640 PMCID: PMC10655719 DOI: 10.1242/dmm.049516] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 09/28/2022] [Indexed: 11/20/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is caused by misexpression of the DUX4 transcription factor in skeletal muscle that results in transcriptional alterations, abnormal phenotypes and cell death. To gain insight into the kinetics of DUX4-induced stresses, we activated DUX4 expression in myoblasts and performed longitudinal RNA sequencing paired with proteomics and phosphoproteomics. This analysis revealed changes in cellular physiology upon DUX4 activation, including DNA damage and altered mRNA splicing. Phosphoproteomic analysis uncovered rapid widespread changes in protein phosphorylation following DUX4 induction, indicating that alterations in kinase signaling might play a role in DUX4-mediated stress and cell death. Indeed, we demonstrate that two stress-responsive MAP kinase pathways, JNK and p38, are activated in response to DUX4 expression. Inhibition of each of these pathways ameliorated DUX4-mediated cell death in myoblasts. These findings uncover that the JNK pathway is involved in DUX4-mediated cell death and provide additional insights into the role of the p38 pathway, a clinical target for the treatment of FSHD.
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Affiliation(s)
- Christopher M. Brennan
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
- WRDM Postdoctoral Program, Pfizer Inc., Cambridge, MA 02139, USA
| | - Abby S. Hill
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | | | - Xianfeng Li
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Vijaya Madeti
- NGS Technology Center, Inflammation and Immunology Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Susanne Breitkopf
- Proteomics Technology Center, Internal Medicine Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Seth Garren
- NGS Technology Center, Inflammation and Immunology Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Liang Xue
- Machine Learning and Computational Science, Pfizer Inc., Cambridge, MA 02139, USA
| | - Tamara Gilbert
- High Content Imaging Technology Center, Internal Medicine Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Angela Hadjipanayis
- NGS Technology Center, Inflammation and Immunology Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Mara Monetti
- Proteomics Technology Center, Internal Medicine Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Charles P. Emerson
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Robert Moccia
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Jane Owens
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
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11
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Lu-Nguyen N, Dickson G, Malerba A, Popplewell L. Long-Term Systemic Treatment of a Mouse Model Displaying Chronic FSHD-like Pathology with Antisense Therapeutics That Inhibit DUX4 Expression. Biomedicines 2022; 10:biomedicines10071623. [PMID: 35884928 PMCID: PMC9313434 DOI: 10.3390/biomedicines10071623] [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: 06/10/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 11/29/2022] Open
Abstract
Silencing the expression of the double homeobox 4 (DUX4) gene offers great potential for the treatment of facioscapulohumeral muscular dystrophy (FSHD). Several research groups have recently reported promising results using systemic antisense therapy in a transgenic small animal model of FSHD, the ACTA1-MCM/FLExDUX4 mouse model. However, the treatment was applied in non-DUX4-induced mice or shortly after DUX4 activation, which resulted in conditions that do not correctly represent the situation in a clinic. Here, we generated progressive FSHD-like pathology in ACTA1-MCM/FLExDUX4 mice and then treated the animals with vivoPMO-PACS4, an antisense compound that efficiently downregulates DUX4. To best mimic the translation of this treatment in clinical settings, the systemic antisense oligonucleotide administration was delayed to 3 weeks after the DUX4 activation so that the pathology was established at the time of the treatment. The chronic administration of vivoPMO-PACS4 for 8 weeks downregulated the DUX4 expression by 60%. Consequently, the treated mice showed an increase by 18% in body-wide muscle mass and 32% in muscle strength, and a reduction in both myofiber central nucleation and muscle fibrosis by up to 29% and 37%, respectively. Our results in a more suitable model of FSHD pathology confirm the efficacy of vivoPMO-PACS4 administration, and highlight the significant benefit provided by the long-term treatment of the disease.
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Affiliation(s)
- Ngoc Lu-Nguyen
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham TW20 0EX, UK; (N.L.-N.); (G.D.)
| | - George Dickson
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham TW20 0EX, UK; (N.L.-N.); (G.D.)
| | - Alberto Malerba
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham TW20 0EX, UK; (N.L.-N.); (G.D.)
- Correspondence: (A.M.); (L.P.)
| | - Linda Popplewell
- Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham TW20 0EX, UK; (N.L.-N.); (G.D.)
- National Horizons Centre, Teesside University, Darlington DL1 1HG, UK
- Correspondence: (A.M.); (L.P.)
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12
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Mellion ML, Widholm P, Karlsson M, Ahlgren A, Tawil R, Wagner KR, Statland JM, Wang L, Shieh PB, van Engelen BGM, Kools J, Ronco L, Odueyungbo A, Jiang J, Han JJ, Hatch M, Towles J, Leinhard OD, Cadavid D. Quantitative Muscle Analysis in FSHD Using Whole-Body Fat-Referenced MRI: Composite Scores for Longitudinal and Cross-Sectional Analysis. Neurology 2022; 99:e877-e889. [PMID: 35750498 DOI: 10.1212/wnl.0000000000200757] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 04/06/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Facioscapulohumeral muscular dystrophy (FSHD) is a rare, debilitating disease characterized by progressive muscle weakness. MRI is a sensitive assessment of disease severity and progression. We developed a quantitative whole-body (WB) musculoskeletal MRI (WB-MSK-MRI) protocol analyzing muscles in their entirety. This study aimed to assess WB-MSK-MRI as a potential imaging biomarker providing reliable measurements of muscle health that capture disease heterogeneity and clinically meaningful composite assessments correlating with severity and more responsive to change in clinical trials. METHODS Participants 18 to 65 years, genetically confirmed FSHD1, clinical severity 2 to 4 (Ricci's scale, range 0-5), and ≥1 short tau inversion recovery (STIR)-positive lower extremity muscle eligible for needle biopsy enrolled at 6 sites; imaged twice 4 - 12 weeks apart. Volumetric analysis of muscle fat infiltration (MFI), muscle fat fraction (MFF), and lean muscle volume (LMV) in 18 (36 total) muscles from bilateral shoulder, proximal arm, trunk, and legs was performed after automated atlas-based segmentation followed by manual verification. A WB composite score, including muscles at highest risk for progression, and functional cross-sectional composites for correlation with relevant functional outcomes including timed up and go (TUG), FSHD-TUG, and reachable workspace (RWS) were developed. RESULTS Seventeen participants;16 follow-up MRIs performed at 52 days (range 36 to 85). Functional cross-sectional composites (MFF and MFI) showed moderate to strong correlations: TUG (rho=0.71, rho=0.83), FSHD-TUG (rho=0.73, rho=0.73), and RWS (left arm: rho=-0.71, rho=-0.53; right arm: rho=-0.61, rho=-0.65). WB composite variability:LMVtot, coefficient of variation (CV) 1.9% and 3.4%; MFFtot, within-subject standard deviation (Sw) 0.5% and 1.5%; MFItot, (Sw), 0.3% and 0.4% for normal and intermediate muscles respectively. CV and Sw were higher in intermediate (MFI≥0.10; MFF<0.50) than in normal (MFI<0.10, MFF<0.50) muscles. DISCUSSION We developed a WB-MSK-MRI protocol and composite measures that capture disease heterogeneity and assess muscle involvement as it correlates with FSHD-relevant clinical endpoints. Functional composites robustly correlate with functional assessments. Stability of the WB composite shows it could be an assessment of change in therapeutic clinical trials. CLASSIFICATION OF EVIDENCE This study provides Class II evidence that quantitative WB-MSK-MRI findings associate with FSHD1 severity measured using established functional assessments.
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Affiliation(s)
| | - Per Widholm
- AMRA Medical AB, Linköping, Sweden.,Department of Radiology and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden.,Centre for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | | | | | - Rabi Tawil
- University of Rochester Medical Center, Rochester, NY
| | - Kathryn R Wagner
- Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD
| | | | - Leo Wang
- University of Washington, Seattle, WA
| | | | | | - Joost Kools
- Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | | | - Jay J Han
- University of California-Irvine, Orange, CA
| | - Maya Hatch
- University of California-Irvine, Orange, CA
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13
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Yu X, Liang S, Chen M, Yu H, Li R, Qu Y, Kong X, Guo R, Zheng R, Izsvák Z, Sun C, Yang M, Wang J. Recapitulating early human development with 8C-like cells. Cell Rep 2022; 39:110994. [PMID: 35732112 DOI: 10.1016/j.celrep.2022.110994] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/21/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
In human embryos, major zygotic genome activation (ZGA) initiates at the eight-cell (8C) stage. Abnormal ZGA leads to developmental defects and even contributes to the failure of human blastocyst formation or implantation. An in vitro cell model mimicking human 8C blastomeres would be invaluable to understanding the mechanisms regulating key biological events during early human development. Using the non-canonical promoter of LEUTX that putatively regulates human ZGA, we developed an 8C::mCherry reporter, which specifically marks the 8C state, to isolate rare 8C-like cells (8CLCs) from human preimplantation epiblast-like stem cells. The 8CLCs express a panel of human ZGA genes and have a unique transcriptome resembling that of the human 8C embryo. Using the 8C::mCherry reporter, we further optimize the chemical-based culture condition to increase and maintain the 8CLC population. Functionally, 8CLCs can self-organize to form blastocyst-like structures. The discovery and maintenance of 8CLCs provide an opportunity to recapitulate early human development.
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Affiliation(s)
- Xiu Yu
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Shiqi Liang
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Manqi Chen
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Hanwen Yu
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Ruiqi Li
- Department of Obstetrics and Gynaecology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Yuliang Qu
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Xuhui Kong
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Ruirui Guo
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Rongyan Zheng
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Zsuzsanna Izsvák
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Chuanbo Sun
- Laboratory of Medical Systems Biology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China.
| | - Mingzhu Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China.
| | - Jichang Wang
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China.
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14
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Himeda CL, Jones PL. FSHD Therapeutic Strategies: What Will It Take to Get to Clinic? J Pers Med 2022; 12:jpm12060865. [PMID: 35743650 PMCID: PMC9225474 DOI: 10.3390/jpm12060865] [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: 05/02/2022] [Revised: 05/17/2022] [Accepted: 05/20/2022] [Indexed: 12/10/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is arguably one of the most challenging genetic diseases to understand and treat. The disease is caused by epigenetic dysregulation of a macrosatellite repeat, either by contraction of the repeat or by mutations in silencing proteins. Both cases lead to chromatin relaxation and, in the context of a permissive allele, pathogenic misexpression of DUX4 in skeletal muscle. The complex nature of the locus and the fact that FSHD is a toxic, gain-of-function disease present unique challenges for the design of therapeutic strategies. There are three major DUX4-targeting avenues of therapy for FSHD: small molecules, oligonucleotide therapeutics, and CRISPR-based approaches. Here, we evaluate the preclinical progress of each avenue, and discuss efforts being made to overcome major hurdles to translation.
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15
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Lu-Nguyen N, Malerba A, Antoni Pineda M, Dickson G, Popplewell LJ. Improving molecular and histopathology in diaphragm muscle of the double transgenic ACTA1-MCM/FLExDUX4 mouse model of FSHD with systemic antisense therapy. Hum Gene Ther 2022; 33:923-935. [PMID: 35078334 DOI: 10.1089/hum.2021.251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a rare muscle dystrophy causing muscle weakness initially in the face, shoulders and upper arms, and extended to lower body muscles as the disease progresses. Respiratory restriction in FSHD is increasingly reported to be more common and severe than previously thought, with the involvement of diaphragm weakness in pulmonary insufficiency being under debate. As aberrant expression of the double homeobox 4 (DUX4) gene is the prime cause of FSHD, we and others have developed numerous strategies and reported promising results on downregulating DUX4 expression in both cellular and animal models of FSHD. However, the effect of DUX4 and anti-DUX4 approaches on diaphragm muscle has not been elucidated. Here we show that toxic DUX4 expression causes pathology that affects the diaphragm of ACTA1-MCM/FLExDUX4 mouse model of FSHD at both molecular and histological levels. Of importance, a systemic antisense treatment that suppresses DUX4 and target genes expression by 50% significantly improves muscle regeneration and muscle fibrosis, and prevents modification in myofiber type composition, supporting its development as a treatment for FSHD.
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Affiliation(s)
- Ngoc Lu-Nguyen
- Royal Holloway University of London, 3162, Department of Biological Sciences, Egham, Surrey, United Kingdom of Great Britain and Northern Ireland;
| | - Alberto Malerba
- Royal Holloway University of London, 3162, Department of Biological Sciences, Egham, Surrey, United Kingdom of Great Britain and Northern Ireland;
| | - Marina Antoni Pineda
- Royal Holloway University of London, 3162, Department of Biological Sciences, Egham, Surrey, United Kingdom of Great Britain and Northern Ireland;
| | - George Dickson
- Royal Holloway University of London, 3162, Department of Biological Sciences, Egham, Surrey, United Kingdom of Great Britain and Northern Ireland;
| | - Linda J Popplewell
- Royal Holloway University of London, 3162, Department of Biological Sciences, Egham, Surrey, United Kingdom of Great Britain and Northern Ireland;
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16
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Mocciaro E, Runfola V, Ghezzi P, Pannese M, Gabellini D. DUX4 Role in Normal Physiology and in FSHD Muscular Dystrophy. Cells 2021; 10:3322. [PMID: 34943834 PMCID: PMC8699294 DOI: 10.3390/cells10123322] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/10/2021] [Accepted: 11/23/2021] [Indexed: 12/12/2022] Open
Abstract
In the last decade, the sequence-specific transcription factor double homeobox 4 (DUX4) has gone from being an obscure entity to being a key factor in important physiological and pathological processes. We now know that expression of DUX4 is highly regulated and restricted to the early steps of embryonic development, where DUX4 is involved in transcriptional activation of the zygotic genome. While DUX4 is epigenetically silenced in most somatic tissues of healthy humans, its aberrant reactivation is associated with several diseases, including cancer, viral infection and facioscapulohumeral muscular dystrophy (FSHD). DUX4 is also translocated, giving rise to chimeric oncogenic proteins at the basis of sarcoma and leukemia forms. Hence, understanding how DUX4 is regulated and performs its activity could provide relevant information, not only to further our knowledge of human embryonic development regulation, but also to develop therapeutic approaches for the diseases associated with DUX4. Here, we summarize current knowledge on the cellular and molecular processes regulated by DUX4 with a special emphasis on FSHD muscular dystrophy.
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Affiliation(s)
| | | | | | | | - Davide Gabellini
- Gene Expression and Muscular Dystrophy Unit, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, 20132 Milano, Italy; (E.M.); (V.R.); (P.G.); (M.P.)
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17
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Jia FF, Drew AP, Nicholson GA, Corbett A, Kumar KR. Facioscapulohumeral muscular dystrophy type 2: an update on the clinical, genetic, and molecular findings. Neuromuscul Disord 2021; 31:1101-1112. [PMID: 34711481 DOI: 10.1016/j.nmd.2021.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/01/2021] [Accepted: 09/09/2021] [Indexed: 11/25/2022]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a common genetic disease of the skeletal muscle with a characteristic pattern of weakness. Facioscapulohumeral muscular dystrophy type 2 (FSHD2) accounts for approximately 5% of all cases of FSHD and describes patients without a D4Z4 repeat contraction on chromosome 4. Phenotypically FSHD2 shows virtually no difference from FSHD1 and both forms of FSHD arise via a common downstream mechanism of epigenetic derepression of the transcription factor DUX4 in skeletal muscle cells. This results in expression of DUX4 and target genes leading to skeletal muscle toxicity. Over the past decade, major progress has been made in our understanding of the genetic and epigenetic architecture that underlies FSHD2 pathogenesis, as well as the clinical manifestations and disease progression. These include the finding that FSHD2 is a digenic disease and that mutations in the genes SMCHD1, DNMT3B, and more recently LRIF1, can cause FSHD2. FSHD2 is complex and it is important that clinicians keep abreast of recent developments; this review aims to serve as an update of the clinical, genetic, and molecular research into this condition.
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Affiliation(s)
- Fangzhi Frank Jia
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia.
| | - Alexander P Drew
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.
| | - Garth Alexander Nicholson
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Northcott Neuroscience Laboratory, ANZAC Research Institute, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
| | - Alastair Corbett
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
| | - Kishore Raj Kumar
- Department of Neurology, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia; Molecular Medicine Laboratory, Concord Repatriation General Hospital, Concord, New South Wales 2139, Australia; Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia.
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18
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Brennan CM, Emerson CP, Owens J, Christoforou N. p38 MAPKs - roles in skeletal muscle physiology, disease mechanisms, and as potential therapeutic targets. JCI Insight 2021; 6:e149915. [PMID: 34156029 PMCID: PMC8262482 DOI: 10.1172/jci.insight.149915] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
p38 MAPKs play a central role in orchestrating the cellular response to stress and inflammation and in the regulation of myogenesis. Potent inhibitors of p38 MAPKs have been pursued as potential therapies for several disease indications due to their antiinflammatory properties, although none have been approved to date. Here, we provide a brief overview of p38 MAPKs, including their role in regulating myogenesis and their association with disease progression. Finally, we discuss targeting p38 MAPKs as a therapeutic approach for treating facioscapulohumeral muscular dystrophy and other muscular dystrophies by addressing multiple pathological mechanisms in skeletal muscle.
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Affiliation(s)
| | - Charles P Emerson
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jane Owens
- Rare Disease Research Unit, Pfizer Inc., Cambridge, Massachusetts, USA
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19
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Mellion ML, Ronco L, Berends CL, Pagan L, Brooks S, van Esdonk MJ, van Brummelen EMJ, Odueyungbo A, Thompson LA, Hage M, Badrising UA, Raines S, Tracewell WG, van Engelen B, Cadavid D, Groeneveld GJ. Phase 1 clinical trial of losmapimod in facioscapulohumeral dystrophy: Safety, tolerability, pharmacokinetics, and target engagement. Br J Clin Pharmacol 2021; 87:4658-4669. [PMID: 33931884 DOI: 10.1111/bcp.14884] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/21/2021] [Indexed: 11/30/2022] Open
Abstract
AIMS Evaluate safety, tolerability, pharmacokinetics (PK) and target engagement (TE) of losmapimod in blood and muscle in facioscapulohumeral dystrophy (FSHD). METHODS This study included Part A: 10 healthy volunteers randomized to single oral doses of losmapimod (7.5 mg then 15 mg; n = 8) or placebo (both periods; n = 2); Part B: 15 FSHD subjects randomized to placebo (n = 3), or losmapimod 7.5 mg (n = 6) or 15 mg (n = 6); and Part C: FSHD subjects received open-label losmapimod 15 mg (n = 5) twice daily for 14 days. Biopsies were performed in FSHD subjects at baseline and Day 14 in magnetic resonance imaging-normal appearing (Part B) and affected muscle identified by abnormal short-tau inversion recovery sequence + (Part C). PK and TE, based on pHSP27:total HSP27, were assessed in muscle and sorbitol-stimulated blood. RESULTS PK profiles were similar between healthy volunteers and FSHD subjects, with mean Cmax and AUC0-12 for 15 mg in FSHD subjects (Part B) of 85.0 ± 16.7 ng*h/mL and 410 ± 50.3 ng*h/mL, respectively. Part B and Part C PK results were similar, and 7.5 mg results were approximately dose proportional to 15 mg results. Dose-dependent concentrations in muscle (42.1 ± 10.5 ng/g [7.5 mg] to 97.2 ± 22.4 ng/g [15 mg]) were observed, with plasma-to-muscle ratio from ~0.67 to ~1 at estimated tmax of 3.5 hours postdose. TE was observed in blood and muscle. Adverse events (AEs) were mild and self-limited. CONCLUSION Losmapimod was well tolerated, with no serious AEs. Dose-dependent PK and TE were observed. This study supports advancing losmapimod into Phase 2 trials in FSHD. CLINICAL TRIAL REGISTRATION Clinical trial identifier ToetsingOnline: NL68539.056.18 Nederlands Trials Register NL8000.
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Affiliation(s)
| | | | | | - Lisa Pagan
- Centre for Human Drug Research (CHDR), Leiden, The Netherlands
| | - Sander Brooks
- Centre for Human Drug Research (CHDR), Leiden, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | - Geert J Groeneveld
- Centre for Human Drug Research (CHDR), Leiden, The Netherlands.,Leiden University Medical Centre, Leiden, The Netherlands
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20
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Karpukhina A, Tiukacheva E, Dib C, Vassetzky YS. Control of DUX4 Expression in Facioscapulohumeral Muscular Dystrophy and Cancer. Trends Mol Med 2021; 27:588-601. [PMID: 33863674 DOI: 10.1016/j.molmed.2021.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022]
Abstract
DUX4, a gene encoding a transcription factor involved in early embryogenesis, is located within the D4Z4 subtelomeric repeat on chromosome 4q35. In most healthy somatic tissues, DUX4 is heavily repressed by multiple genetic and epigenetic mechanisms, and its aberrant expression is linked to facioscapulohumeral muscular dystrophy (FSHD) where it has been extensively studied. Recently, DUX4 expression has been implicated in oncogenesis, although this is much less explored. In this review, we discuss multiple levels of control of DUX4 expression, including enhancer-promoter interactions, DNA methylation, histone modifications, noncoding RNAs, and telomere positioning effect. We also connect disparate data on intrachromosomal contacts involving DUX4 and emphasize the feedback loops in DUX4 regulation. Finally, we bridge data on DUX4 in FSHD and cancer and discuss prospective approaches for future FSHD therapies and the potential outcomes of DUX4 inhibition in cancer.
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Affiliation(s)
- Anna Karpukhina
- UMR 9018, CNRS, Université Paris Saclay, Institut Gustave Roussy, Villejuif F-94805, France; Koltzov Institute of Developmental Biology, Moscow 117334, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Eugenia Tiukacheva
- UMR 9018, CNRS, Université Paris Saclay, Institut Gustave Roussy, Villejuif F-94805, France
| | - Carla Dib
- UMR 9018, CNRS, Université Paris Saclay, Institut Gustave Roussy, Villejuif F-94805, France; Stanford University School of Medicine, Stanford, CA 94305-510, USA
| | - Yegor S Vassetzky
- UMR 9018, CNRS, Université Paris Saclay, Institut Gustave Roussy, Villejuif F-94805, France; Koltzov Institute of Developmental Biology, Moscow 117334, Russia.
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21
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Schätzl T, Kaiser L, Deigner HP. Facioscapulohumeral muscular dystrophy: genetics, gene activation and downstream signalling with regard to recent therapeutic approaches: an update. Orphanet J Rare Dis 2021; 16:129. [PMID: 33712050 PMCID: PMC7953708 DOI: 10.1186/s13023-021-01760-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Whilst a disease-modifying treatment for Facioscapulohumeral muscular dystrophy (FSHD) does not exist currently, recent advances in complex molecular pathophysiology studies of FSHD have led to possible therapeutic approaches for its targeted treatment. Although the underlying genetics of FSHD have been researched extensively, there remains an incomplete understanding of the pathophysiology of FSHD in relation to the molecules leading to DUX4 gene activation and the downstream gene targets of DUX4 that cause its toxic effects. In the context of the local proximity of chromosome 4q to the nuclear envelope, a contraction of the D4Z4 macrosatellite induces lower methylation levels, enabling the ectopic expression of DUX4. This disrupts numerous signalling pathways that mostly result in cell death, detrimentally affecting skeletal muscle in affected individuals. In this regard different options are currently explored either to suppress the transcription of DUX4 gene, inhibiting DUX4 protein from its toxic effects, or to alleviate the symptoms triggered by its numerous targets.
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Affiliation(s)
- Teresa Schätzl
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Straße 17, 78054, Villingen-Schwenningen, Germany
| | - Lars Kaiser
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Straße 17, 78054, Villingen-Schwenningen, Germany
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstraße 25, 79104, Freiburg i. Br., Germany
| | - Hans-Peter Deigner
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Straße 17, 78054, Villingen-Schwenningen, Germany.
- EXIM Department, Fraunhofer Institute IZI, Leipzig, Schillingallee 68, 18057, Rostock, Germany.
- Faculty of Science, Tuebingen University, Auf der Morgenstelle 8, 72076, Tübingen, Germany.
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22
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Cohen J, DeSimone A, Lek M, Lek A. Therapeutic Approaches in Facioscapulohumeral Muscular Dystrophy. Trends Mol Med 2021; 27:123-137. [PMID: 33092966 PMCID: PMC8048701 DOI: 10.1016/j.molmed.2020.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 01/13/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common types of muscular dystrophy, affecting roughly one in 8000 individuals. The complex underlying genetics and poor mechanistic understanding has caused a bottleneck in therapeutic development. Until the discovery of DUX4 and its causal role in FSHD, most trials were untargeted with limited results. Emerging approaches can learn from these early trials to increase their chance of success. Here, we explore the evolution of FSHD clinical trials from nonspecific anabolic or anti-inflammatory/oxidant strategies to cutting-edge molecular therapies targeting DUX4, and we discuss the importance of clinical outcome measures. With combined advances across multiple facets of FSHD research, the field is now poised to accelerate the process of therapeutic discovery and testing.
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Affiliation(s)
- Justin Cohen
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Alec DeSimone
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Monkol Lek
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Angela Lek
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.
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23
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Current Genetic Survey and Potential Gene-Targeting Therapeutics for Neuromuscular Diseases. Int J Mol Sci 2020; 21:ijms21249589. [PMID: 33339321 PMCID: PMC7767109 DOI: 10.3390/ijms21249589] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 12/17/2022] Open
Abstract
Neuromuscular diseases (NMDs) belong to a class of functional impairments that cause dysfunctions of the motor neuron-muscle functional axis components. Inherited monogenic neuromuscular disorders encompass both muscular dystrophies and motor neuron diseases. Understanding of their causative genetic defects and pathological genetic mechanisms has led to the unprecedented clinical translation of genetic therapies. Challenged by a broad range of gene defect types, researchers have developed different approaches to tackle mutations by hijacking the cellular gene expression machinery to minimize the mutational damage and produce the functional target proteins. Such manipulations may be directed to any point of the gene expression axis, such as classical gene augmentation, modulating premature termination codon ribosomal bypass, splicing modification of pre-mRNA, etc. With the soar of the CRISPR-based gene editing systems, researchers now gravitate toward genome surgery in tackling NMDs by directly correcting the mutational defects at the genome level and expanding the scope of targetable NMDs. In this article, we will review the current development of gene therapy and focus on NMDs that are available in published reports, including Duchenne Muscular Dystrophy (DMD), Becker muscular dystrophy (BMD), X-linked myotubular myopathy (XLMTM), Spinal Muscular Atrophy (SMA), and Limb-girdle muscular dystrophy Type 2C (LGMD2C).
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24
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Himeda CL, Jones TI, Jones PL. Targeted epigenetic repression by CRISPR/dSaCas9 suppresses pathogenic DUX4-fl expression in FSHD. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 20:298-311. [PMID: 33511244 PMCID: PMC7806950 DOI: 10.1016/j.omtm.2020.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/02/2020] [Indexed: 02/07/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is caused by incomplete silencing of the disease locus, leading to pathogenic misexpression of DUX4 in skeletal muscle. Previously, we showed that CRISPR inhibition could successfully target and repress DUX4 in FSHD myocytes. However, an effective therapy will require both efficient delivery of therapeutic components to skeletal muscles and long-term repression of the disease locus. Thus, we re-engineered our platform to allow in vivo delivery of more potent epigenetic repressors. We designed an FSHD-optimized regulatory cassette to drive skeletal muscle-specific expression of dCas9 from Staphylococcus aureus fused to HP1α, HP1γ, the MeCP2 transcriptional repression domain, or the SUV39H1 SET domain. Targeting each regulator to the DUX4 promoter/exon 1 increased chromatin repression at the locus, specifically suppressing DUX4 and its target genes in FSHD myocytes and in a mouse model of the disease. Importantly, minimizing the regulatory cassette and using the smaller Cas9 ortholog allowed our therapeutic cassettes to be effectively packaged into adeno-associated virus (AAV) vectors for in vivo delivery. By engineering a muscle-specific epigenetic CRISPR platform compatible with AAV vectors for gene therapy, we have laid the groundwork for clinical use of dCas9-based chromatin effectors in skeletal muscle disorders.
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Affiliation(s)
- Charis L. Himeda
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Takako I. Jones
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Peter L. Jones
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
- Corresponding author Peter L. Jones, Department of Pharmacology, Center for Molecular Medicine/MS-0318, University of Nevada, Reno School of Medicine, 1664 N. Virginia St., Reno, NV 89557, USA.
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25
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Rashnonejad A, Amini-Chermahini G, Taylor NK, Wein N, Harper SQ. Designed U7 snRNAs inhibit DUX4 expression and improve FSHD-associated outcomes in DUX4 overexpressing cells and FSHD patient myotubes. MOLECULAR THERAPY-NUCLEIC ACIDS 2020; 23:476-486. [PMID: 33510937 PMCID: PMC7807095 DOI: 10.1016/j.omtn.2020.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/06/2020] [Indexed: 12/21/2022]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) arises from epigenetic changes that de-repress the DUX4 gene in muscle. The full-length DUX4 protein causes cell death and muscle toxicity, and therefore we hypothesize that FSHD therapies should center on inhibiting full-length DUX4 expression. In this study, we developed a strategy to accomplish DUX4 inhibition using U7-small nuclear RNA (snRNA) antisense expression cassettes (called U7-asDUX4). These non-coding RNAs were designed to inhibit production or maturation of the full-length DUX4 pre-mRNA by masking the DUX4 start codon, splice sites, or polyadenylation signal. In so doing, U7-asDUX4 snRNAs operate similarly to antisense oligonucleotides. However, in contrast to oligonucleotides, which are limited by poor uptake in muscle and a requirement for lifelong repeated dosing, U7-asDUX4 snRNAs can be packaged within myotropic gene therapy vectors and may require only a single administration when delivered to post-mitotic cells in vivo. We tested several U7-asDUX4s that reduced DUX4 expression in vitro and improved DUX4-associated outcomes. Inhibition of DUX4 expression via U7-snRNAs could be a new prospective gene therapy approach for FSHD or be used in combination with other strategies, like RNAi therapy, to maximize DUX4 silencing in individuals with FSHD.
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Affiliation(s)
- Afrooz Rashnonejad
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
| | - Gholamhossein Amini-Chermahini
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
| | - Noah K Taylor
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
| | - Nicolas Wein
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Scott Q Harper
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
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26
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Bouwman LF, van der Maarel SM, de Greef JC. The prospects of targeting DUX4 in facioscapulohumeral muscular dystrophy. Curr Opin Neurol 2020; 33:635-640. [PMID: 32796277 PMCID: PMC7735392 DOI: 10.1097/wco.0000000000000849] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Facioscapulohumeral muscular dystrophy (FSHD) is a neuromuscular disorder, which is caused by incomplete repression of the transcription factor double homeobox 4 (DUX4) in skeletal muscle. To date, there is no DUX4-targeting treatment to prevent or delay disease progression. In the present review, we summarize developments in therapeutic strategies with the focus on inhibiting DUX4 and DUX4 target gene expression. RECENT FINDINGS Different studies show that DUX4 and its target genes can be repressed with genetic therapies using diverse strategies. Additionally, different small compounds can reduce DUX4 and its target genes in vitro and in vivo. SUMMARY Most studies that show DUX4 repression by genetic therapies have only been tested in vitro. More efforts should be made to test them in vivo for clinical translation. Several compounds have been shown to prevent DUX4 and target gene expression in vitro and in vivo. However, their efficiency and specificity has not yet been shown. With emerging clinical trials, the clinical benefit from DUX4 repression in FSHD will likely soon become apparent.
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Affiliation(s)
- Linde F Bouwman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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27
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Therapeutic Strategies Targeting DUX4 in FSHD. J Clin Med 2020; 9:jcm9092886. [PMID: 32906621 PMCID: PMC7564105 DOI: 10.3390/jcm9092886] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/20/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is a common muscle dystrophy typically affecting patients within their second decade. Patients initially exhibit asymmetric facial and humeral muscle damage, followed by lower body muscle involvement. FSHD is associated with a derepression of DUX4 gene encoded by the D4Z4 macrosatellite located on the subtelomeric part of chromosome 4. DUX4 is a highly regulated transcription factor and its expression in skeletal muscle contributes to multiple cellular toxicities and pathologies ultimately leading to muscle weakness and atrophy. Since the discovery of the FSHD candidate gene DUX4, many cell and animal models have been designed for therapeutic approaches and clinical trials. Today there is no treatment available for FSHD patients and therapeutic strategies targeting DUX4 toxicity in skeletal muscle are being actively investigated. In this review, we will discuss different research areas that are currently being considered to alter DUX4 expression and toxicity in muscle tissue and the cell and animal models designed to date.
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