1
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Sun C, Serra C, Kalicharan BH, Harding J, Rao M. Challenges and Considerations of Preclinical Development for iPSC-Based Myogenic Cell Therapy. Cells 2024; 13:596. [PMID: 38607035 PMCID: PMC11011706 DOI: 10.3390/cells13070596] [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: 02/06/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Abstract
Cell therapies derived from induced pluripotent stem cells (iPSCs) offer a promising avenue in the field of regenerative medicine due to iPSCs' expandability, immune compatibility, and pluripotent potential. An increasing number of preclinical and clinical trials have been carried out, exploring the application of iPSC-based therapies for challenging diseases, such as muscular dystrophies. The unique syncytial nature of skeletal muscle allows stem/progenitor cells to integrate, forming new myonuclei and restoring the expression of genes affected by myopathies. This characteristic makes genome-editing techniques especially attractive in these therapies. With genetic modification and iPSC lineage specification methodologies, immune-compatible healthy iPSC-derived muscle cells can be manufactured to reverse the progression of muscle diseases or facilitate tissue regeneration. Despite this exciting advancement, much of the development of iPSC-based therapies for muscle diseases and tissue regeneration is limited to academic settings, with no successful clinical translation reported. The unknown differentiation process in vivo, potential tumorigenicity, and epigenetic abnormality of transplanted cells are preventing their clinical application. In this review, we give an overview on preclinical development of iPSC-derived myogenic cell transplantation therapies including processes related to iPSC-derived myogenic cells such as differentiation, scaling-up, delivery, and cGMP compliance. And we discuss the potential challenges of each step of clinical translation. Additionally, preclinical model systems for testing myogenic cells intended for clinical applications are described.
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Affiliation(s)
- Congshan Sun
- Vita Therapeutics, Baltimore, MD 21043, USA (M.R.)
| | - Carlo Serra
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | - Mahendra Rao
- Vita Therapeutics, Baltimore, MD 21043, USA (M.R.)
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2
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Cohen J, Huang S, Koczwara KE, Woods KT, Ho V, Woodman KG, Arbiser JL, Daman K, Lek M, Emerson CP, DeSimone AM. Flavones provide resistance to DUX4-induced toxicity via an mTor-independent mechanism. Cell Death Dis 2023; 14:749. [PMID: 37973788 PMCID: PMC10654915 DOI: 10.1038/s41419-023-06257-2] [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: 01/06/2023] [Revised: 10/10/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is among the most common of the muscular dystrophies, affecting nearly 1 in 8000 individuals, and is a cause of profound disability. Genetically, FSHD is linked to the contraction and/or epigenetic de-repression of the D4Z4 repeat array on chromosome 4, thereby allowing expression of the DUX4 gene in skeletal muscle. If the DUX4 transcript incorporates a stabilizing polyadenylation site the myotoxic DUX4 protein will be synthesized, resulting in muscle wasting. The mechanism of toxicity remains unclear, as many DUX4-induced cytopathologies have been described, however cell death does primarily occur through caspase 3/7-dependent apoptosis. To date, most FSHD therapeutic development has focused on molecular methods targeting DUX4 expression or the DUX4 transcript, while therapies targeting processes downstream of DUX4 activity have received less attention. Several studies have demonstrated that inhibition of multiple signal transduction pathways can ameliorate DUX4-induced toxicity, and thus compounds targeting these pathways have the potential to be developed into FSHD therapeutics. To this end, we have screened a group of small molecules curated based on their reported activity in relevant pathways and/or structural relationships with known toxicity-modulating molecules. We have identified a panel of five compounds that function downstream of DUX4 activity to inhibit DUX4-induced toxicity. Unexpectedly, this effect was mediated through an mTor-independent mechanism that preserved expression of ULK1 and correlated with an increase in a marker of active cellular autophagy. This identifies these flavones as compounds of interest for therapeutic development, and potentially identifies the autophagy pathway as a target for therapeutics.
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Affiliation(s)
- Justin Cohen
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Shushu Huang
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | | | - Kristen T Woods
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Disease Research University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Vincent Ho
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Keryn G Woodman
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | | | - Katelyn Daman
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Disease Research University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Monkol Lek
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Charles P Emerson
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Li Weibo Institute for Rare Disease Research University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Alec M DeSimone
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA.
- Modalis Therapeutics, Waltham, MA, USA.
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3
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Griazeva ED, Fedoseeva DM, Radion EI, Ershov PV, Meshkov IO, Semyanihina AV, Makarova AS, Makarov VV, Yudin VS, Keskinov AA, Kraevoy SA. Current Approaches to Epigenetic Therapy. EPIGENOMES 2023; 7:23. [PMID: 37873808 PMCID: PMC10594535 DOI: 10.3390/epigenomes7040023] [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: 08/24/2023] [Revised: 09/14/2023] [Accepted: 09/17/2023] [Indexed: 10/25/2023] Open
Abstract
Epigenetic therapy is a promising tool for the treatment of a wide range of diseases. Several fundamental epigenetic approaches have been proposed. Firstly, the use of small molecules as epigenetic effectors, as the most developed pharmacological method, has contributed to the introduction of a number of drugs into clinical practice. Secondly, various innovative epigenetic approaches based on dCas9 and the use of small non-coding RNAs as therapeutic agents are also under extensive research. In this review, we present the current state of research in the field of epigenetic therapy, considering the prospects for its application and possible limitations.
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Affiliation(s)
- Ekaterina D. Griazeva
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Daria M. Fedoseeva
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Elizaveta I. Radion
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Pavel V. Ershov
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Ivan O. Meshkov
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Alexandra V. Semyanihina
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
- Federal State Budgetary Institution “N.N. Blokhin National Medical Research Center of Oncology” of the Ministry of Health of the Russian Federation (N.N. Blokhin NMRCO), Kashirskoe Shosse, 24, Moscow 115478, Russia
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moskvorechye, 1, Moscow 115522, Russia
| | - Anna S. Makarova
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Valentin V. Makarov
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Vladimir S. Yudin
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Anton A. Keskinov
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
| | - Sergey A. Kraevoy
- Federal State Budgetary Institution, Centre for Strategic Planning and Management of Biomedical Health Risks of the Federal Medical Biological Agency, Pogodinskaya Str., 10, Building 1, Moscow 119121, Russia
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4
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Padberg GW, van Engelen BGM, Voermans NC. Facioscapulohumeral Disease as a myodevelopmental disease: Applying Ockham's razor to its various features. J Neuromuscul Dis 2023; 10:411-425. [PMID: 36872787 DOI: 10.3233/jnd-221624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an exclusively human neuromuscular disease. In the last decades the cause of FSHD was identified: the loss of epigenetic repression of the D4Z4 repeat on chromosome 4q35 resulting in inappropriate transcription of DUX4. This is a consequence of a reduction of the array below 11 units (FSHD1) or of a mutation in methylating enzymes (FSHD2). Both require the presence of a 4qA allele and a specific centromeric SSLP haplotype. Muscles become involved in a rostro-caudally order with an extremely variable progression rate. Mild disease and non-penetrance in families with affected individuals is common. Furthermore, 2% of the Caucasian population carries the pathological haplotype without clinical features of FSHD.In order to explain the various features of FSHD we applied Ockham's Razor to all possible scenarios and removed unnecessary complexities. We postulate that early in embryogenesis a few cells escape epigenetic silencing of the D4Z4 repeat. Their number is assumed to be roughly inversely related to the residual D4Z4 repeat size. By asymmetric cell division, they produce a rostro-caudal and medio-lateral decreasing gradient of weakly D4Z4-repressed mesenchymal stem cells. The gradient tapers towards an end as each cell-division allows renewed epigenetic silencing. Over time, this spatial gradient translates into a temporal gradient based on a decreasing number of weakly silenced stem cells. These cells contribute to a mildly abnormal myofibrillar structure of the fetal muscles. They also form a downward tapering gradient of epigenetically weakly repressed satellite cells. When activated by mechanical trauma, these satellite cells de-differentiate and express DUX4. When fused to myofibrils they contribute to muscle cell death in various ways. Over time and dependent on how far the gradient reaches the FSHD phenotype becomes progressively manifest. We thus hypothesize FSHD to be a myodevelopmental disease with a lifelong attempt to restore DUX4 repression.
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Affiliation(s)
- G W Padberg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - B G M van Engelen
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - N C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
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5
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Cohen J, Huang S, Koczwara K, Ho V, Woodman K, Lek A, Arbiser J, Lek M, DeSimone A. Flavones provide resistance to DUX4-induced toxicity via an mTor-independent mechanism. RESEARCH SQUARE 2023:rs.3.rs-2452222. [PMID: 36778471 PMCID: PMC9915774 DOI: 10.21203/rs.3.rs-2452222/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is among the most common of the muscular dystrophies, affecting nearly 1 in 8000 individuals, and is a cause of profound disability. Genetically, FSHD is linked to the contraction and/or epigenetic de-repression of the D4Z4 repeat array on chromosome 4, thereby allowing expression of the DUX4 gene in skeletal muscle. If the DUX4 transcript incorporates a stabilizing polyadenylation site the myotoxic DUX4 protein will be synthesized, resulting in muscle wasting. The mechanism of toxicity remains unclear, as many DUX4-induced cytopathologies have been described, however cell death does primarily occur through caspase 3/7-dependent apoptosis. To date, most FSHD therapeutic development has focused on molecular methods targeting DUX4 expression or the DUX4 transcript, while therapies targeting processes downstream of DUX4 activity have received less attention. Several studies have demonstrated that inhibition of multiple signal transduction pathways can ameliorate DUX4-induced toxicity, and thus compounds targeting these pathways have the potential to be developed into FSHD therapeutics. To this end, we have screened a group of small molecules curated based on their reported activity in relevant pathways and/or structural relationships with known toxicity-modulating molecules. We have identified a panel of five compounds that function downstream of DUX4 activity to inhibit DUX4-induced toxicity. Unexpectedly, this effect was mediated through an mTor-independent mechanism that preserved expression of ULK1 and correlated with an increase in a marker of active cellular autophagy. This identifies these flavones as compounds of interest for therapeutic development, and potentially identifies the autophagy pathway as a target for therapeutics.
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6
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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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7
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Mul K. Facioscapulohumeral Muscular Dystrophy. Continuum (Minneap Minn) 2022; 28:1735-1751. [PMID: 36537978 DOI: 10.1212/con.0000000000001155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This article reviews the current knowledge on the clinical characteristics and disease mechanism of facioscapulohumeral muscular dystrophy (FSHD), as well as advances in targeted therapy development. RECENT FINDINGS FSHD has a wide range of severity, yet a distinct phenotype characterized by weakness of the facial, shoulder, and upper arm muscles, followed by weakness of the trunk and leg muscles. It can be caused by two genetic mechanisms that share a common downstream pathway, namely, the epigenetic derepression and subsequent misexpression of the myotoxic DUX4 transcription factor. Treatment is currently supportive and outlined in evidence-based guidelines. Advances in the understanding of the pathogenic mechanism of FSHD are paving the way for targeted therapy development. Approaches for targeted therapies to reduce DUX4 expression that are currently being explored include small molecules, antisense oligonucleotides, vector-based RNA interference, and gene therapy. In anticipation of more clinical trials, "clinical trial preparedness," including the development of sensitive biomarkers and clinical outcome measures, are needed. SUMMARY The cornerstones of the diagnosis of FSHD are clinical observation and genetic testing. Management is currently supportive, but progress in the understanding of the disease mechanism has shifted the field of FSHD toward targeted therapy development.
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8
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Mariot V, Dumonceaux J. Gene Editing to Tackle Facioscapulohumeral Muscular Dystrophy. Front Genome Ed 2022; 4:937879. [PMID: 35910413 PMCID: PMC9334676 DOI: 10.3389/fgeed.2022.937879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Facioscapulohumeral dystrophy (FSHD) is a skeletal muscle disease caused by the aberrant expression of the DUX4 gene in the muscle tissue. To date, different therapeutic approaches have been proposed, targeting DUX4 at the DNA, RNA or protein levels. The recent development of the clustered regularly interspaced short-palindromic repeat (CRISPR) based technology opened new avenues of research, and FSHD is no exception. For the first time, a cure for genetic muscular diseases can be considered. Here, we describe CRISPR-based strategies that are currently being investigated for FSHD. The different approaches include the epigenome editing targeting the DUX4 gene and its promoter, gene editing targeting the polyadenylation of DUX4 using TALEN, CRISPR/cas9 or adenine base editing and the CRISPR-Cas9 genome editing for SMCHD1. We also discuss challenges facing the development of these gene editing based therapeutics.
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Lensch S, Herschl MH, Ludwig CH, Sinha J, Hinks MM, Mukund A, Fujimori T, Bintu L. Dynamic spreading of chromatin-mediated gene silencing and reactivation between neighboring genes in single cells. eLife 2022; 11:e75115. [PMID: 35678392 PMCID: PMC9183234 DOI: 10.7554/elife.75115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/23/2022] [Indexed: 12/02/2022] Open
Abstract
In mammalian cells genes that are in close proximity can be transcriptionally coupled: silencing or activating one gene can affect its neighbors. Understanding these dynamics is important for natural processes, such as heterochromatin spreading during development and aging, and when designing synthetic gene regulation circuits. Here, we systematically dissect this process in single cells by recruiting and releasing repressive chromatin regulators at dual-gene synthetic reporters, and measuring how fast gene silencing and reactivation spread as a function of intergenic distance and configuration of insulator elements. We find that silencing by KRAB, associated with histone methylation, spreads between two genes within hours, with a time delay that increases with distance. This fast KRAB-mediated spreading is not blocked by the classical cHS4 insulators. Silencing by histone deacetylase HDAC4 of the upstream gene can also facilitate background silencing of the downstream gene by PRC2, but with a days-long delay that does not change with distance. This slower silencing can sometimes be stopped by insulators. Gene reactivation of neighboring genes is also coupled, with strong promoters and insulators determining the order of reactivation. Our data can be described by a model of multi-gene regulation that builds upon previous knowledge of heterochromatin spreading, where both gene silencing and gene reactivation can act at a distance, allowing for coordinated dynamics via chromatin regulator recruitment.
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Affiliation(s)
- Sarah Lensch
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Michael H Herschl
- University of California, Berkeley—University of California, San Francisco Graduate Program in BioengineeringBerkeleyUnited States
| | - Connor H Ludwig
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Joydeb Sinha
- Department of Chemical and Systems Biology, Stanford UniversityStanfordUnited States
| | - Michaela M Hinks
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Adi Mukund
- Biophysics Program, Stanford UniversityStanfordUnited States
| | - Taihei Fujimori
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Lacramioara Bintu
- Department of Bioengineering, Stanford UniversityStanfordUnited States
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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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11
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Masteika IF, Sathya A, Homma S, Miller BM, Boyce FM, Miller JB. Downstream events initiated by expression of FSHD-associated DUX4: Studies of nucleocytoplasmic transport, γH2AX accumulation, and Bax/Bak-dependence. Biol Open 2022; 11:274475. [PMID: 35191484 PMCID: PMC8890089 DOI: 10.1242/bio.059145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/12/2022] [Indexed: 12/15/2022] Open
Abstract
Abnormal expression in skeletal muscle of the double homeobox transcription factor DUX4 underlies pathogenesis in facioscapulohumeral muscular dystrophy (FSHD). Though multiple changes are known to be initiated by aberrant DUX4 expression, the downstream events initiated by DUX4 remain incompletely understood. In this study, we examined plausible downstream events initiated by DUX4. First, we found that nucleocytoplasmic protein export appeared to be decreased upon DUX4 expression as indicated by nuclear accumulation of a shuttle-GFP reporter. Second, building on studies from other labs, we showed that phospho(Ser139)-H2AX (γH2AX), an indicator of double-strand DNA breaks, accumulated both in human FSHD1 myotube nuclei upon endogenous DUX4 expression and in Bax-/-;Bak-/- (double knockout), SV40-immortalized mouse embryonic fibroblasts upon exogenous DUX4 expression. In contrast, DUX4-induced caspase 3/7 activation was prevented in Bax-/-;Bak-/- double knockout SV40-MEFs, but not by single knockouts of Bax, Bak, or Bid. Thus, aberrant DUX4 expression appeared to alter nucleocytoplasmic protein transport and generate double-strand DNA breaks in FSHD1 myotube nuclei, and the Bax/Bak pathway is required for DUX4-induced caspase activation but not γH2AX accumulation. These results add to our knowledge of downstream events induced by aberrant DUX4 expression and suggest possibilities for further mechanistic investigation.
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Affiliation(s)
- Isabel F Masteika
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Anvitha Sathya
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Sachiko Homma
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Bess M Miller
- Biological & Biomedical Sciences Program, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Frederick M Boyce
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Jeffrey Boone Miller
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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12
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Lorenz P, Steinbeck F, Krause L, Thiesen HJ. The KRAB Domain of ZNF10 Guides the Identification of Specific Amino Acids That Transform the Ancestral KRAB-A-Related Domain Present in Human PRDM9 into a Canonical Modern KRAB-A Domain. Int J Mol Sci 2022; 23:ijms23031072. [PMID: 35162997 PMCID: PMC8835667 DOI: 10.3390/ijms23031072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 12/14/2022] Open
Abstract
Krüppel-associated box (KRAB) zinc finger proteins are a large class of tetrapod transcription factors that usually exert transcriptional repression through recruitment of TRIM28/KAP1. The evolutionary root of modern KRAB domains (mKRAB) can be traced back to an ancestral motif (aKRAB) that occurs even in invertebrates. Here, we first stratified three subgroups of aKRAB sequences from the animal kingdom (PRDM9, SSX and coelacanth KZNF families) and defined ancestral subdomains for KRAB-A and KRAB-B. Using human ZNF10 mKRAB-AB as blueprints for function, we then identified the necessary amino acid changes that transform the inactive aKRAB-A of human PRDM9 into an mKRAB domain capable of mediating silencing and complexing TRIM28/KAP1 in human cells when employed as a hybrid with ZNF10-B. Full gain of function required replacement of residues KR by the conserved motif MLE (positionsA32-A34), which inserted an additional residue, and exchange of A9/S for F, A20/M for L, and A27/R for V. AlphaFold2 modelling documented an evolutionary conserved L-shaped body of two α-helices in all KRAB domains. It is transformed into a characteristic spatial arrangement typical for mKRAB-AB upon the amino acid replacements and in conjunction with a third helix supplied by mKRAB-B. Side-chains pointing outward from the core KRAB 3D structure may reveal a protein-protein interaction code enabling graded binding of TRIM28 to different KRAB domains. Our data provide basic insights into structure-function relationships and emulate transitions of KRAB during evolution.
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Affiliation(s)
- Peter Lorenz
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany; (F.S.); (L.K.); (H.-J.T.)
- Correspondence: ; Tel.: +49-(0)381-494-5879; Fax: +49-(0)381-494-5882
| | - Felix Steinbeck
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany; (F.S.); (L.K.); (H.-J.T.)
| | - Ludwig Krause
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany; (F.S.); (L.K.); (H.-J.T.)
| | - Hans-Jürgen Thiesen
- Rostock University Medical Center, Institute of Immunology, Schillingallee 70, 18057 Rostock, Germany; (F.S.); (L.K.); (H.-J.T.)
- Gesellschaft für Individualisierte Medizin (IndyMed) mbH, 17, 18055 Rostock, Germany
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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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