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Han TW, Portz B, Young RA, Boija A, Klein IA. RNA and condensates: Disease implications and therapeutic opportunities. Cell Chem Biol 2024; 31:1593-1609. [PMID: 39303698 DOI: 10.1016/j.chembiol.2024.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 08/14/2024] [Accepted: 08/21/2024] [Indexed: 09/22/2024]
Abstract
Biomolecular condensates are dynamic membraneless organelles that compartmentalize proteins and RNA molecules to regulate key cellular processes. Diverse RNA species exert their effects on the cell by their roles in condensate formation and function. RNA abnormalities such as overexpression, modification, and mislocalization can lead to pathological condensate behaviors that drive various diseases, including cancer, neurological disorders, and infections. Here, we review RNA's role in condensate biology, describe the mechanisms of RNA-induced condensate dysregulation, note the implications for disease pathogenesis, and discuss novel therapeutic strategies. Emerging approaches to targeting RNA within condensates, including small molecules and RNA-based therapies that leverage the unique properties of condensates, may revolutionize treatment for complex diseases.
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Affiliation(s)
| | | | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ann Boija
- Dewpoint Therapeutics, Boston, MA, USA.
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2
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Dong L, Gao L. SP1-Driven FOXM1 Upregulation Induces Dopaminergic Neuron Injury in Parkinson's Disease. Mol Neurobiol 2024; 61:5510-5524. [PMID: 38200349 DOI: 10.1007/s12035-023-03854-2] [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: 01/31/2023] [Accepted: 11/22/2023] [Indexed: 01/12/2024]
Abstract
The aberrant expression of Forkhead box M1 (FOXM1) has been associated with the pathological processes of Parkinson's disease (PD), but the upstream and downstream regulators remain poorly understood. This study sought to examine the underlying mechanism of FOXM1 in dopaminergic neuron injury in PD. Bioinformatics analysis was conducted to pinpoint the differential expression of FOXM1, which was verified in the nigral tissues of rotenone-lesioned mice and dopaminergic neuron MN9D cells. Interactions among SP1, FOXM1, SNAI2, and CXCL12 were analyzed. To evaluate their effects on dopaminergic neuron injury, the lentiviral vector-mediated manipulation of FOXM1, SP1, and CXCL12 was introduced in rotenone-lesioned mice and MN9D cells. SP1, FOXM1, SNAI2, and CXCL12 abundant expression occurred in rotenone-lesioned mice and MN9D cells. Silencing of FOXM1 delayed the rotenone-induced dopaminergic neuron injury in vitro. Mechanistically, SP1 was an upstream transcription factor of FOXM1 and upregulated FOXM1 expression, leading to increased SNAI2 and CXCL12 expression. In vivo, data confirmed that SP1 promoted dopaminergic neuron injury by activating the FOXM1/SNAI2/CXCL12 axis. Our data indicate that SP1 silencing has neuroprotective effects on dopaminergic neurons, which is dependent upon the inactivated FOXM1/SNAI2/CXCL12 axis.
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Affiliation(s)
- Li Dong
- Department of Neurology, The Fourth Affiliated Hospital of China Medical University, No. 4, Chongshan East Road, Huanggu District, Shenyang, 110032, Liaoning Province, People's Republic of China.
| | - Lianbo Gao
- Department of Neurology, The Fourth Affiliated Hospital of China Medical University, No. 4, Chongshan East Road, Huanggu District, Shenyang, 110032, Liaoning Province, People's Republic of China
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3
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Yu L, Liu L. Exploration of adverse events associated with risdiplam use: Retrospective cases from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. PLoS One 2024; 19:e0298609. [PMID: 38427665 PMCID: PMC10906863 DOI: 10.1371/journal.pone.0298609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/26/2024] [Indexed: 03/03/2024] Open
Abstract
Risdiplam is a new drug for treating spinal muscular atrophy (SMA). However, pharmacovigilance analyses are necessary to objectively evaluate its safety-a crucial step in preventing severe adverse events (AEs). Accordingly, the primary objective of the current study was to examine the AEs associated with risdiplam use based on real-world data obtained from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. More specifically, we examined incidents reported between the third quarter of 2020 and the second quarter of 2023. The imbalance of risdiplam-related AEs was evaluated by computing the reporting odds ratio. A total of 5,406,334 reports were thoroughly reviewed. By removing duplicate reports, we identified 1588 reports in which risdiplam was the main suspected drug whose use was accompanied by 3470 associated AEs. Among the included AEs, 703 were categorized as serious and 885 as non-serious. Risdiplam use induced AEs across 18 organ systems, resulting in 130 positive signals. Notably, we detected new AE signals, including cardiac arrest, nephrolithiasis, tachycardia, loss of libido, and elevated hepatic enzyme activities; however, no ophthalmologic toxicity was reported. Although these new adverse reaction signals associated with risdiplam have been defined, long-term clinical studies are needed to confirm these findings. Nevertheless, our findings provide a valuable reference for improving the clinical management of SMA.
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Affiliation(s)
- Lurong Yu
- College of Traditional Chinese Medicine of Chongqing Medical University, Chongqing, China
| | - Limei Liu
- Pharmacy Department of Chongqing YouYou BaoBei Women’s and Children’s Hospital, Chongqing, China
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4
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Ishigami Y, Wong MS, Martí-Gómez C, Ayaz A, Kooshkbaghi M, Hanson SM, McCandlish DM, Krainer AR, Kinney JB. Specificity, synergy, and mechanisms of splice-modifying drugs. Nat Commun 2024; 15:1880. [PMID: 38424098 PMCID: PMC10904865 DOI: 10.1038/s41467-024-46090-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 02/10/2024] [Indexed: 03/02/2024] Open
Abstract
Drugs that target pre-mRNA splicing hold great therapeutic potential, but the quantitative understanding of how these drugs work is limited. Here we introduce mechanistically interpretable quantitative models for the sequence-specific and concentration-dependent behavior of splice-modifying drugs. Using massively parallel splicing assays, RNA-seq experiments, and precision dose-response curves, we obtain quantitative models for two small-molecule drugs, risdiplam and branaplam, developed for treating spinal muscular atrophy. The results quantitatively characterize the specificities of risdiplam and branaplam for 5' splice site sequences, suggest that branaplam recognizes 5' splice sites via two distinct interaction modes, and contradict the prevailing two-site hypothesis for risdiplam activity at SMN2 exon 7. The results also show that anomalous single-drug cooperativity, as well as multi-drug synergy, are widespread among small-molecule drugs and antisense-oligonucleotide drugs that promote exon inclusion. Our quantitative models thus clarify the mechanisms of existing treatments and provide a basis for the rational development of new therapies.
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Affiliation(s)
- Yuma Ishigami
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Mandy S Wong
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- Beam Therapeutics, Cambridge, MA, 02142, USA
| | | | - Andalus Ayaz
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Mahdi Kooshkbaghi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- The Estée Lauder Companies, New York, NY, 10153, USA
| | | | | | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
| | - Justin B Kinney
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
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5
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Rocca R, Grillone K, Citriniti EL, Gualtieri G, Artese A, Tagliaferri P, Tassone P, Alcaro S. Targeting non-coding RNAs: Perspectives and challenges of in-silico approaches. Eur J Med Chem 2023; 261:115850. [PMID: 37839343 DOI: 10.1016/j.ejmech.2023.115850] [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: 07/25/2023] [Revised: 09/08/2023] [Accepted: 09/29/2023] [Indexed: 10/17/2023]
Abstract
The growing information currently available on the central role of non-coding RNAs (ncRNAs) including microRNAs (miRNAS) and long non-coding RNAs (lncRNAs) for chronic and degenerative human diseases makes them attractive therapeutic targets. RNAs carry out different functional roles in human biology and are deeply deregulated in several diseases. So far, different attempts to therapeutically target the 3D RNA structures with small molecules have been reported. In this scenario, the development of computational tools suitable for describing RNA structures and their potential interactions with small molecules is gaining more and more interest. Here, we describe the most suitable strategies to study ncRNAs through computational tools. We focus on methods capable of predicting 2D and 3D ncRNA structures. Furthermore, we describe computational tools to identify, design and optimize small molecule ncRNA binders. This review aims to outline the state of the art and perspectives of computational methods for ncRNAs over the past decade.
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Affiliation(s)
- Roberta Rocca
- Department of Health Science, Magna Graecia University, Catanzaro, Italy; Net4Science srl, Academic Spinoff, Magna Græcia University, Catanzaro, Italy
| | - Katia Grillone
- Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, Italy
| | | | | | - Anna Artese
- Department of Health Science, Magna Graecia University, Catanzaro, Italy; Net4Science srl, Academic Spinoff, Magna Græcia University, Catanzaro, Italy.
| | | | - Pierfrancesco Tassone
- Department of Experimental and Clinical Medicine, Magna Græcia University, Catanzaro, Italy
| | - Stefano Alcaro
- Department of Health Science, Magna Graecia University, Catanzaro, Italy; Net4Science srl, Academic Spinoff, Magna Græcia University, Catanzaro, Italy
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6
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Ottesen EW, Singh NN, Luo D, Kaas B, Gillette B, Seo J, Jorgensen H, Singh RN. Diverse targets of SMN2-directed splicing-modulating small molecule therapeutics for spinal muscular atrophy. Nucleic Acids Res 2023; 51:5948-5980. [PMID: 37026480 PMCID: PMC10325915 DOI: 10.1093/nar/gkad259] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/13/2023] [Accepted: 03/28/2023] [Indexed: 04/08/2023] Open
Abstract
Designing an RNA-interacting molecule that displays high therapeutic efficacy while retaining specificity within a broad concentration range remains a challenging task. Risdiplam is an FDA-approved small molecule for the treatment of spinal muscular atrophy (SMA), the leading genetic cause of infant mortality. Branaplam is another small molecule which has undergone clinical trials. The therapeutic merit of both compounds is based on their ability to restore body-wide inclusion of Survival Motor Neuron 2 (SMN2) exon 7 upon oral administration. Here we compare the transcriptome-wide off-target effects of these compounds in SMA patient cells. We captured concentration-dependent compound-specific changes, including aberrant expression of genes associated with DNA replication, cell cycle, RNA metabolism, cell signaling and metabolic pathways. Both compounds triggered massive perturbations of splicing events, inducing off-target exon inclusion, exon skipping, intron retention, intron removal and alternative splice site usage. Our results of minigenes expressed in HeLa cells provide mechanistic insights into how these molecules targeted towards a single gene produce different off-target effects. We show the advantages of combined treatments with low doses of risdiplam and branaplam. Our findings are instructive for devising better dosing regimens as well as for developing the next generation of small molecule therapeutics aimed at splicing modulation.
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Affiliation(s)
- Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Diou Luo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Bailey Kaas
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Benjamin J Gillette
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Hannah J Jorgensen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
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7
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Khorkova O, Stahl J, Joji A, Volmar CH, Wahlestedt C. Amplifying gene expression with RNA-targeted therapeutics. Nat Rev Drug Discov 2023; 22:539-561. [PMID: 37253858 PMCID: PMC10227815 DOI: 10.1038/s41573-023-00704-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2023] [Indexed: 06/01/2023]
Abstract
Many diseases are caused by insufficient expression of mutated genes and would benefit from increased expression of the corresponding protein. However, in drug development, it has been historically easier to develop drugs with inhibitory or antagonistic effects. Protein replacement and gene therapy can achieve the goal of increased protein expression but have limitations. Recent discoveries of the extensive regulatory networks formed by non-coding RNAs offer alternative targets and strategies to amplify the production of a specific protein. In addition to RNA-targeting small molecules, new nucleic acid-based therapeutic modalities that allow highly specific modulation of RNA-based regulatory networks are being developed. Such approaches can directly target the stability of mRNAs or modulate non-coding RNA-mediated regulation of transcription and translation. This Review highlights emerging RNA-targeted therapeutics for gene activation, focusing on opportunities and challenges for translation to the clinic.
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Affiliation(s)
- Olga Khorkova
- OPKO Health, Miami, FL, USA
- Center for Therapeutic Innovation, University of Miami, Miami, FL, USA
| | - Jack Stahl
- Center for Therapeutic Innovation, University of Miami, Miami, FL, USA
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL, USA
| | - Aswathy Joji
- Center for Therapeutic Innovation, University of Miami, Miami, FL, USA
- Department of Chemistry, University of Miami, Miami, FL, USA
| | - Claude-Henry Volmar
- Center for Therapeutic Innovation, University of Miami, Miami, FL, USA
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL, USA
| | - Claes Wahlestedt
- Center for Therapeutic Innovation, University of Miami, Miami, FL, USA.
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL, USA.
- Department of Chemistry, University of Miami, Miami, FL, USA.
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8
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Torroba B, Macabuag N, Haisma EM, O'Neill A, Herva ME, Redis RS, Templin MV, Black LE, Fischer DF. RNA-based drug discovery for spinal muscular atrophy: a story of small molecules and antisense oligonucleotides. Expert Opin Drug Discov 2023; 18:181-192. [PMID: 36408582 DOI: 10.1080/17460441.2022.2149733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Spinal Muscular Atrophy (SMA), the second most prevalent autosomal genetic disease affecting infants, is caused by the lack of SMN1, which encodes a neuron functioning vital protein, SMN. Improving exon 7 splicing in the paralogous gene SMN2, also coding for SMN protein, increases protein production efficiency from SMN2 to overcome the genetic deficit in SMN1. Several molecular mechanisms have been investigated to improve SMN2 functional splicing. AREAS COVERED This manuscript will cover two of the three mechanistically distinct available treatment options for SMA, both targeting the SMN2 splicing mechanism. The first therapeutic, nusinersen (Spinraza®, 2017), is an antisense oligonucleotide (ASO) targeting the splicing inhibitory sequence in the intron downstream of exon 7 from SMN2, thus increasing exon 7 inclusion. The second drug is a small molecule, risdiplam (Evrysdi®, 2021), that enhances the binding of splice factors and also promotes exon 7 inclusion. Both therapies, albeit through different mechanisms, increase full-length SMN protein expression. EXPERT OPINION Nusinersen and risdiplam have directly helped SMA patients and families, but they also herald a sea change in drug development for genetic diseases. This piece aims to draw parallels between both development histories; this may help chart the course for future targeted agents.
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Affiliation(s)
| | | | | | - Amy O'Neill
- Charles River Laboratories, Saffron Walden, UK
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9
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Lightfoot HL, Smith GF. Targeting RNA with small molecules-A safety perspective. Br J Pharmacol 2023. [PMID: 36631428 DOI: 10.1111/bph.16027] [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: 02/24/2022] [Revised: 06/30/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023] Open
Abstract
RNA is a major player in cellular function, and consequently can drive a number of disease pathologies. Over the past several years, small molecule-RNA targeting (smRNA targeting) has developed into a promising drug discovery approach. Numerous techniques, tools, and assays have been developed to support this field, and significant investments have been made by pharmaceutical and biotechnology companies. To date, the focus has been on identifying disease validated primary targets for smRNA drug development, yet RNA as a secondary (off) target for all small molecule drug programs largely has been unexplored. In this perspective, we discuss structure, target, and mechanism-driven safety aspects of smRNAs and highlight how these parameters can be evaluated in drug discovery programs to produce potentially safer drugs.
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Affiliation(s)
- Helen L Lightfoot
- Safety and Mechanistic Pharmacology, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge, UK
| | - Graham F Smith
- Data Science and AI, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge, UK
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10
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Rozza R, Janoš P, Spinello A, Magistrato A. Role of computational and structural biology in the development of small-molecule modulators of the spliceosome. Expert Opin Drug Discov 2022; 17:1095-1109. [PMID: 35983696 DOI: 10.1080/17460441.2022.2114452] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION RNA splicing is a pivotal step of eukaryotic gene expression during which the introns are excised from the precursor (pre-)RNA and the exons are joined together to form mature RNA products (i.e a protein-coding mRNA or long non-coding (lnc)RNAs). The spliceosome, a complex ribonucleoprotein machine, performs pre-RNA splicing with extreme precision. Deregulated splicing is linked to cancer, genetic, and neurodegenerative diseases. Hence, the discovery of small-molecules targeting core spliceosome components represents an appealing therapeutic opportunity. AREA COVERED Several atomic-level structures of the spliceosome and distinct splicing-modulators bound to its protein/RNA components have been solved. Here, we review recent advances in the discovery of small-molecule splicing-modulators, discuss opportunities and challenges for their therapeutic applicability, and showcase how structural data and/or all-atom simulations can illuminate key facets of their mechanism, thus contributing to future drug-discovery campaigns. EXPERT OPINION This review highlights the potential of modulating pre-RNA splicing with small-molecules, and anticipates how the synergy of computer and wet-lab experiments will enrich our understanding of splicing regulation/deregulation mechanisms. This information will aid future structure-based drug-discovery efforts aimed to expand the currently limited portfolio of selective splicing-modulators.
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Affiliation(s)
- Riccardo Rozza
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
| | - Pavel Janoš
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
| | - Angelo Spinello
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo, Palermo, Italy
| | - Alessandra Magistrato
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
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11
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Byun WG, Lim D, Park SB. Small-molecule modulators of protein–RNA interactions. Curr Opin Chem Biol 2022; 68:102149. [DOI: 10.1016/j.cbpa.2022.102149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/16/2022]
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12
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Zhang L, Abendroth F, Vázquez O. A Chemical Biology Perspective to Therapeutic Regulation of RNA Splicing in Spinal Muscular Atrophy (SMA). ACS Chem Biol 2022; 17:1293-1307. [PMID: 35639849 DOI: 10.1021/acschembio.2c00161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Manipulation of RNA splicing machinery has emerged as a drug modality. Here, we illustrate the potential of this novel paradigm to correct aberrant splicing events focused on the recent therapeutic advances in spinal muscular atrophy (SMA). SMA is an incurable neuromuscular disorder and at present the primary genetic cause of early infant death. This Review summarizes the exciting journey from the first reported SMA cases to the currently approved splicing-switching treatments, i.e., antisense oligonucleotides and small-molecule modifiers. We emphasize both chemical structures and molecular bases for recognition. We briefly discuss the advantages and disadvantages of these treatments and include the remaining challenges and future directions. Finally, we also predict that these success stories will contribute to further therapies for human diseases by RNA-splicing control.
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Affiliation(s)
- Lei Zhang
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Frank Abendroth
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Olalla Vázquez
- Department of Chemistry, University of Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), University of Marburg, Karl-von-Frisch-Straße 14, 35043 Marburg, Germany
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13
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Johns AE, Maragakis NJ. Exploring Motor Neuron Diseases Using iPSC Platforms. Stem Cells 2022; 40:2-13. [PMID: 35511862 PMCID: PMC9199844 DOI: 10.1093/stmcls/sxab006] [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: 06/18/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The degeneration of motor neurons is a pathological hallmark of motor neuron diseases (MNDs), but emerging evidence suggests that neuronal vulnerability extends well beyond this cell subtype. The ability to assess motor function in the clinic is limited to physical examination, electrophysiological measures, and tissue-based or neuroimaging techniques which lack the resolution to accurately assess neuronal dysfunction as the disease progresses. Spinal muscular atrophy (SMA), spinal and bulbar muscular atrophy (SBMA), hereditary spastic paraplegia (HSP), and amyotrophic lateral sclerosis (ALS) are all MNDs with devastating clinical outcomes that contribute significantly to disease burden as patients are no longer able to carry out normal activities of daily living. The critical need to accurately assess the cause and progression of motor neuron dysfunction, especially in the early stages of those diseases, has motivated the use of human iPSC-derived motor neurons (hiPSC-MN) to study the neurobiological mechanisms underlying disease pathogenesis and to generate platforms for therapeutic discovery and testing. As our understanding of MNDs has grown, so too has our need to develop more complex in vitro models which include hiPSC-MN co-cultured with relevant non-neuronal cells in 2D as well as in 3D organoid and spheroid systems. These more complex hiPSC-derived culture systems have led to the implementation of new technologies, including microfluidics, multielectrode array, and machine learning which offer novel insights into the functional correlates of these emerging model systems.
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Affiliation(s)
- Alexandra E Johns
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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14
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Sergeeva OV, Shcherbinina EY, Shomron N, Zatsepin TS. Modulation of RNA Splicing by Oligonucleotides: Mechanisms of Action and Therapeutic Implications. Nucleic Acid Ther 2022; 32:123-138. [PMID: 35166605 DOI: 10.1089/nat.2021.0067] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of RNA splicing causes many diseases and disorders. Several therapeutic approaches have been developed to correct aberrant alternative splicing events for the treatment of cancers and hereditary diseases, including gene therapy and redirecting splicing, using small molecules or splice switching oligonucleotides (SSO). Significant advances in the chemistry and pharmacology of nucleic acid have led to the development of clinically approved SSO drugs for the treatment of spinal muscular dystrophy and Duchenne muscular dystrophy (DMD). In this review, we discuss the mechanisms of SSO action with emphasis on "less common" approaches to modulate alternative splicing, including bipartite and bifunctional SSO, oligonucleotide decoys for splice factors and SSO-mediated mRNA degradation via AS-NMD and NGD pathways. We briefly discuss the current progress and future perspectives of SSO therapy for rare and ultrarare diseases.
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Affiliation(s)
- Olga V Sergeeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | | | - Noam Shomron
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Timofei S Zatsepin
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia.,Department of Chemistry, Moscow State University, Moscow, Russia
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15
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Small molecule splicing modifiers with systemic HTT-lowering activity. Nat Commun 2021; 12:7299. [PMID: 34911927 PMCID: PMC8674292 DOI: 10.1038/s41467-021-27157-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 10/28/2021] [Indexed: 02/07/2023] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin (HTT) gene. Consequently, the mutant protein is ubiquitously expressed and drives pathogenesis of HD through a toxic gain-of-function mechanism. Animal models of HD have demonstrated that reducing huntingtin (HTT) protein levels alleviates motor and neuropathological abnormalities. Investigational drugs aim to reduce HTT levels by repressing HTT transcription, stability or translation. These drugs require invasive procedures to reach the central nervous system (CNS) and do not achieve broad CNS distribution. Here, we describe the identification of orally bioavailable small molecules with broad distribution throughout the CNS, which lower HTT expression consistently throughout the CNS and periphery through selective modulation of pre-messenger RNA splicing. These compounds act by promoting the inclusion of a pseudoexon containing a premature termination codon (stop-codon psiExon), leading to HTT mRNA degradation and reduction of HTT levels.
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16
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Towards Splicing Therapy for Lysosomal Storage Disorders: Methylxanthines and Luteolin Ameliorate Splicing Defects in Aspartylglucosaminuria and Classic Late Infantile Neuronal Ceroid Lipofuscinosis. Cells 2021; 10:cells10112813. [PMID: 34831035 PMCID: PMC8616534 DOI: 10.3390/cells10112813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 10/01/2021] [Accepted: 10/15/2021] [Indexed: 12/22/2022] Open
Abstract
Splicing defects caused by mutations in the consensus sequences at the borders of introns and exons are common in human diseases. Such defects frequently result in a complete loss of function of the protein in question. Therapy approaches based on antisense oligonucleotides for specific gene mutations have been developed in the past, but they are very expensive and require invasive, life-long administration. Thus, modulation of splicing by means of small molecules is of great interest for the therapy of genetic diseases resulting from splice-site mutations. Using minigene approaches and patient cells, we here show that methylxanthine derivatives and the food-derived flavonoid luteolin are able to enhance the correct splicing of the AGA mRNA with a splice-site mutation c.128-2A>G in aspartylglucosaminuria, and result in increased AGA enzyme activity in patient cells. Furthermore, we also show that one of the most common disease causing TPP1 gene variants in classic late infantile neuronal ceroid lipofuscinosis may also be amenable to splicing modulation using similar substances. Therefore, our data suggest that splice-modulation with small molecules may be a valid therapy option for lysosomal storage disorders.
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17
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Choi K, Yang A, Baek J, Jeong H, Kang Y, Baek W, Kim JC, Kang M, Choi M, Ham Y, Son MJ, Han SB, Kim J, Jang JH, Ahn JS, Shen H, Woo SH, Kim JH, Cho S. Regulation of Survival Motor Neuron Gene Expression by Calcium Signaling. Int J Mol Sci 2021; 22:ijms221910234. [PMID: 34638572 PMCID: PMC8508836 DOI: 10.3390/ijms221910234] [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: 07/28/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 11/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous survival of motor neurons 1 (SMN1) gene deletion, leaving a duplicate gene, SMN2, as the sole source of SMN protein. However, a defect in SMN2 splicing, involving exon 7 skipping, results in a low level of functional SMN protein. Therefore, the upregulation of SMN protein expression from the SMN2 gene is generally considered to be one of the best therapeutic strategies to treat SMA. Most of the SMA drug discovery is based on synthetic compounds, and very few natural compounds have been explored thus far. Here, we performed an unbiased mechanism-independent and image-based screen of a library of microbial metabolites in SMA fibroblasts using an SMN-specific immunoassay. In doing so, we identified brefeldin A (BFA), a well-known inhibitor of ER-Golgi protein trafficking, as a strong inducer of SMN protein. The profound increase in SMN protein was attributed to, in part, the rescue of the SMN2 pre-mRNA splicing defect. Intriguingly, BFA increased the intracellular calcium concentration, and the BFA-induced exon 7 inclusion of SMN2 splicing, was abrogated by the depletion of intracellular calcium and by the pharmacological inhibition of calcium/calmodulin-dependent kinases (CaMKs). Moreover, BFA considerably reduced the expression of Tra2-β and SRSF9 proteins in SMA fibroblasts and enhanced the binding of PSF and hnRNP M to an exonic splicing enhancer (ESE) of exon 7. Together, our results demonstrate a significant role for calcium and its signaling on the regulation of SMN splicing, probably through modulating the expression/activity of splicing factors.
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Affiliation(s)
- Kwangman Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Medical Biotechnology, SoonChunHyang University, Asan 31538, Korea
| | - Ansook Yang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Jiyeon Baek
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Hyejeong Jeong
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Yura Kang
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Woosun Baek
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Joon-Chul Kim
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Mingu Kang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Miri Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Youngwook Ham
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
| | - Min-Jeong Son
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea;
| | - Jae-Hyuk Jang
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Jong Seog Ahn
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Haihong Shen
- Gwangju Institute of Science and Technology, School of life Sciences, Gwangju 61005, Korea;
| | - Sun-Hee Woo
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Jong Heon Kim
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Sungchan Cho
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
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18
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Lejman J, Zieliński G, Gawda P, Lejman M. Alternative Splicing Role in New Therapies of Spinal Muscular Atrophy. Genes (Basel) 2021; 12:1346. [PMID: 34573328 PMCID: PMC8468182 DOI: 10.3390/genes12091346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
It has been estimated that 80% of the pre-mRNA undergoes alternative splicing, which exponentially increases the flow of biological information in cellular processes and can be an attractive therapeutic target. It is a crucial mechanism to increase genetic diversity. Disturbed alternative splicing is observed in many disorders, including neuromuscular diseases and carcinomas. Spinal Muscular Atrophy (SMA) is an autosomal recessive neurodegenerative disease. Homozygous deletion in 5q13 (the region coding for the motor neuron survival gene (SMN1)) is responsible for 95% of SMA cases. The nearly identical SMN2 gene does not compensate for SMN loss caused by SMN1 gene mutation due to different splicing of exon 7. A pathologically low level of survival motor neuron protein (SMN) causes degeneration of the anterior horn cells in the spinal cord with associated destruction of α-motor cells and manifested by muscle weakness and loss. Understanding the regulation of the SMN2 pre-mRNA splicing process has allowed for innovative treatment and the introduction of new medicines for SMA. After describing the concept of splicing modulation, this review will cover the progress achieved in this field, by highlighting the breakthrough accomplished recently for the treatment of SMA using the mechanism of alternative splicing.
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Affiliation(s)
- Jan Lejman
- Student Scientific Society, Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland;
| | - Grzegorz Zieliński
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Piotr Gawda
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Monika Lejman
- Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland
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Tang Z, Akhter S, Ramprasad A, Wang X, Reibarkh M, Wang J, Aryal S, Thota SS, Zhao J, Douglas JT, Gao P, Holmstrom ED, Miao Y, Wang J. Recognition of single-stranded nucleic acids by small-molecule splicing modulators. Nucleic Acids Res 2021; 49:7870-7883. [PMID: 34283224 PMCID: PMC8373063 DOI: 10.1093/nar/gkab602] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 12/16/2022] Open
Abstract
Risdiplam is the first approved small-molecule splicing modulator for the treatment of spinal muscular atrophy (SMA). Previous studies demonstrated that risdiplam analogues have two separate binding sites in exon 7 of the SMN2 pre-mRNA: (i) the 5'-splice site and (ii) an upstream purine (GA)-rich binding site. Importantly, the sequence of this GA-rich binding site significantly enhanced the potency of risdiplam analogues. In this report, we unambiguously determined that a known risdiplam analogue, SMN-C2, binds to single-stranded GA-rich RNA in a sequence-specific manner. The minimum required binding sequence for SMN-C2 was identified as GAAGGAAGG. We performed all-atom simulations using a robust Gaussian accelerated molecular dynamics (GaMD) method, which captured spontaneous binding of a risdiplam analogue to the target nucleic acids. We uncovered, for the first time, a ligand-binding pocket formed by two sequential GAAG loop-like structures. The simulation findings were highly consistent with experimental data obtained from saturation transfer difference (STD) NMR and structure-affinity-relationship studies of the risdiplam analogues. Together, these studies illuminate us to understand the molecular basis of single-stranded purine-rich RNA recognition by small-molecule splicing modulators with an unprecedented binding mode.
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Affiliation(s)
- Zhichao Tang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Sana Akhter
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Ankita Ramprasad
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Xiao Wang
- Analytical Research & Development, Merck and Co., Inc., Kenilworth, NJ 07033, USA
| | - Mikhail Reibarkh
- Analytical Research & Development, Merck and Co., Inc., Kenilworth, NJ 07033, USA
| | - Jinan Wang
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Sadikshya Aryal
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Srinivas S Thota
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Junxing Zhao
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Justin T Douglas
- Nuclear Magnetic Resonance Lab, University of Kansas, Lawrence, KS 66045, USA
| | - Philip Gao
- Protein Production Group, University of Kansas, Lawrence, KS 66047, USA
| | - Erik D Holmstrom
- Department of Molecular Biosciences and Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047, USA
| | - Jingxin Wang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047, USA
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20
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Ottesen EW, Luo D, Singh NN, Singh RN. High Concentration of an ISS-N1-Targeting Antisense Oligonucleotide Causes Massive Perturbation of the Transcriptome. Int J Mol Sci 2021; 22:ijms22168378. [PMID: 34445083 PMCID: PMC8395096 DOI: 10.3390/ijms22168378] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/14/2021] [Accepted: 07/31/2021] [Indexed: 12/17/2022] Open
Abstract
Intronic splicing silencer N1 (ISS-N1) located within Survival Motor Neuron 2 (SMN2) intron 7 is the target of a therapeutic antisense oligonucleotide (ASO), nusinersen (Spinraza), which is currently being used for the treatment of spinal muscular atrophy (SMA), a leading genetic disease associated with infant mortality. The discovery of ISS-N1 as a promising therapeutic target was enabled in part by Anti-N1, a 20-mer ASO that restored SMN2 exon 7 inclusion by annealing to ISS-N1. Here, we analyzed the transcriptome of SMA patient cells treated with 100 nM of Anti-N1 for 30 h. Such concentrations are routinely used to demonstrate the efficacy of an ASO. While 100 nM of Anti-N1 substantially stimulated SMN2 exon 7 inclusion, it also caused massive perturbations in the transcriptome and triggered widespread aberrant splicing, affecting expression of essential genes associated with multiple cellular processes such as transcription, splicing, translation, cell signaling, cell cycle, macromolecular trafficking, cytoskeletal dynamics, and innate immunity. We validated our findings with quantitative and semiquantitative PCR of 39 candidate genes associated with diverse pathways. We also showed a substantial reduction in off-target effects with shorter ISS-N1-targeting ASOs. Our findings are significant for implementing better ASO design and dosing regimens of ASO-based drugs.
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21
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Salucci S, Bartoletti Stella A, Battistelli M, Burattini S, Bavelloni A, Cocco LI, Gobbi P, Faenza I. How Inflammation Pathways Contribute to Cell Death in Neuro-Muscular Disorders. Biomolecules 2021; 11:1109. [PMID: 34439778 PMCID: PMC8391499 DOI: 10.3390/biom11081109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022] Open
Abstract
Neuro-muscular disorders include a variety of diseases induced by genetic mutations resulting in muscle weakness and waste, swallowing and breathing difficulties. However, muscle alterations and nerve depletions involve specific molecular and cellular mechanisms which lead to the loss of motor-nerve or skeletal-muscle function, often due to an excessive cell death. Morphological and molecular studies demonstrated that a high number of these disorders seem characterized by an upregulated apoptosis which significantly contributes to the pathology. Cell death involvement is the consequence of some cellular processes that occur during diseases, including mitochondrial dysfunction, protein aggregation, free radical generation, excitotoxicity and inflammation. The latter represents an important mediator of disease progression, which, in the central nervous system, is known as neuroinflammation, characterized by reactive microglia and astroglia, as well the infiltration of peripheral monocytes and lymphocytes. Some of the mechanisms underlying inflammation have been linked to reactive oxygen species accumulation, which trigger mitochondrial genomic and respiratory chain instability, autophagy impairment and finally neuron or muscle cell death. This review discusses the main inflammatory pathways contributing to cell death in neuro-muscular disorders by highlighting the main mechanisms, the knowledge of which appears essential in developing therapeutic strategies to prevent the consequent neuron loss and muscle wasting.
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Affiliation(s)
- Sara Salucci
- Department of Biomolecular Sciences (DiSB), Urbino University Carlo Bo, 61029 Urbino, Italy; (M.B.); (S.B.); (P.G.)
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, 40126 Bologna, Italy; (L.I.C.); (I.F.)
| | - Anna Bartoletti Stella
- Department of Diagnostic Experimental and Specialty Medicine (DIMES), University of Bologna, 40126 Bologna, Italy;
| | - Michela Battistelli
- Department of Biomolecular Sciences (DiSB), Urbino University Carlo Bo, 61029 Urbino, Italy; (M.B.); (S.B.); (P.G.)
| | - Sabrina Burattini
- Department of Biomolecular Sciences (DiSB), Urbino University Carlo Bo, 61029 Urbino, Italy; (M.B.); (S.B.); (P.G.)
| | - Alberto Bavelloni
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy;
| | - Lucio Ildebrando Cocco
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, 40126 Bologna, Italy; (L.I.C.); (I.F.)
| | - Pietro Gobbi
- Department of Biomolecular Sciences (DiSB), Urbino University Carlo Bo, 61029 Urbino, Italy; (M.B.); (S.B.); (P.G.)
| | - Irene Faenza
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, 40126 Bologna, Italy; (L.I.C.); (I.F.)
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Chaytow H, Faller KM, Huang YT, Gillingwater TH. Spinal muscular atrophy: From approved therapies to future therapeutic targets for personalized medicine. Cell Rep Med 2021; 2:100346. [PMID: 34337562 PMCID: PMC8324491 DOI: 10.1016/j.xcrm.2021.100346] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating childhood motor neuron disease that, in the most severe cases and when left untreated, leads to death within the first two years of life. Recent therapeutic advances have given hope to families and patients by compensating for the deficiency in survival motor neuron (SMN) protein via gene therapy or other genetic manipulation. However, it is now apparent that none of these therapies will cure SMA alone. In this review, we discuss the three currently licensed therapies for SMA, briefly highlighting their respective advantages and disadvantages, before considering alternative approaches to increasing SMN protein levels. We then explore recent preclinical research that is identifying and targeting dysregulated pathways secondary to, or independent of, SMN deficiency that may provide adjunctive opportunities for SMA. These additional therapies are likely to be key for the development of treatments that are effective across the lifespan of SMA patients.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Kiterie M.E. Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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El Marabti E, Abdel-Wahab O. Therapeutic Modulation of RNA Splicing in Malignant and Non-Malignant Disease. Trends Mol Med 2021; 27:643-659. [PMID: 33994320 DOI: 10.1016/j.molmed.2021.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/11/2021] [Accepted: 04/13/2021] [Indexed: 01/24/2023]
Abstract
RNA splicing is the enzymatic process by which non-protein coding sequences are removed from RNA to produce mature protein-coding mRNA. Splicing is thereby a major mediator of proteome diversity as well as a dynamic regulator of gene expression. Genetic alterations disrupting splicing of individual genes or altering the function of splicing factors contribute to a wide range of human genetic diseases as well as cancer. These observations have resulted in the development of therapies based on oligonucleotides that bind to RNA sequences and modulate splicing for therapeutic benefit. In parallel, small molecules that bind to splicing factors to alter their function or modify RNA processing of individual transcripts are being pursued for monogenic disorders as well as for cancer.
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Affiliation(s)
- Ettaib El Marabti
- Clinical Transplant Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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24
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Roberto J, Poulin KL, Parks RJ, Vacratsis PO. Label-free quantitative proteomic analysis of extracellular vesicles released from fibroblasts derived from patients with spinal muscular atrophy. Proteomics 2021; 21:e2000301. [PMID: 33893753 DOI: 10.1002/pmic.202000301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/22/2021] [Accepted: 04/12/2021] [Indexed: 11/10/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder that represents a significant cause of infant mortality. SMA is characterized by reduced levels of the Survival Motor Neuron protein leading to the loss of alpha motor neurons in the spinal cord and brain stem as well as defects in peripheral tissues such as skeletal muscle and liver. With progress in promising therapies such as antisense oligonucleotide and gene replacement, there remains a need to better understand disease subtypes and develop biomarkers for improved diagnostics and therapeutic monitoring. In this study, we have examined the utility of extracellular vesicles as a source of biomarker discovery in patient-derived fibroblast cells. Proteome examination utilizing data-independent acquisition and ion mobility mass spectrometry identified 684 protein groups present in all biological replicates tested. Label-free quantitative analysis identified 116 statistically significant protein alterations compared to control cells, including several known SMA biomarkers. Protein level differences were also observed in regulators of Wnt signaling and Cajal bodies. Finally, levels of insulin growth factor binding protein-3 were validated as being significantly higher in extracellular vesicles isolated from SMA cells. We conclude that extracellular vesicles represent a promising source for SMA biomarker discovery as well as a relevant constituent for advancing our understanding of SMA pathophysiology.
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Affiliation(s)
- Justin Roberto
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada
| | - Kathy L Poulin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Panayiotis O Vacratsis
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada
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25
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Cappella M, Elouej S, Biferi MG. The Potential of Induced Pluripotent Stem Cells to Test Gene Therapy Approaches for Neuromuscular and Motor Neuron Disorders. Front Cell Dev Biol 2021; 9:662837. [PMID: 33937264 PMCID: PMC8080375 DOI: 10.3389/fcell.2021.662837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
The reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) represents a major advance for the development of human disease models. The emerging of this technique fostered the concept of "disease in a dish," which consists into the generation of patient-specific models in vitro. Currently, iPSCs are used to study pathological molecular mechanisms caused by genetic mutations and they are considered a reliable model for high-throughput drug screenings. Importantly, precision-medicine approaches to treat monogenic disorders exploit iPSCs potential for the selection and validation of lead candidates. For example, antisense oligonucleotides (ASOs) were tested with promising results in myoblasts or motor neurons differentiated from iPSCs of patients affected by either Duchenne muscular dystrophy or Amyotrophic lateral sclerosis. However, the use of iPSCs needs additional optimization to ensure translational success of the innovative strategies based on gene delivery through adeno associated viral vectors (AAV) for these diseases. Indeed, to establish an efficient transduction of iPSCs with AAV, several aspects should be optimized, including viral vector serotype, viral concentration and timing of transduction. This review will outline the use of iPSCs as a model for the development and testing of gene therapies for neuromuscular and motor neuron disorders. It will then discuss the advantages for the use of this versatile tool for gene therapy, along with the challenges associated with the viral vector transduction of iPSCs.
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Affiliation(s)
- Marisa Cappella
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
| | - Sahar Elouej
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
| | - Maria Grazia Biferi
- Sorbonne University, INSERM, Institute of Myology, Center of Research in Myology, Paris, France
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Singh RN, Ottesen EW, Singh NN. The First Orally Deliverable Small Molecule for the Treatment of Spinal Muscular Atrophy. Neurosci Insights 2020; 15:2633105520973985. [PMID: 33283185 PMCID: PMC7691903 DOI: 10.1177/2633105520973985] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is 1 of the leading causes of infant mortality. SMA
is mostly caused by low levels of Survival Motor Neuron (SMN) protein due to
deletion of or mutation in the SMN1 gene. Its nearly identical
copy, SMN2, fails to compensate for the loss of
SMN1 due to predominant skipping of exon 7. Correction of
SMN2 exon 7 splicing by an antisense oligonucleotide (ASO),
nusinersen (Spinraza™), that targets the intronic splicing silencer N1 (ISS-N1)
became the first approved therapy for SMA. Restoration of SMN levels using gene
therapy was the next. Very recently, an orally deliverable small molecule,
risdiplam (Evrysdi™), became the third approved therapy for SMA. Here we discuss
how these therapies are positioned to meet the needs of the broad phenotypic
spectrum of SMA patients.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
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