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Medicinal Research Reviews Sep 2021Movement disorders are a group of neurological conditions characterized by abnormalities of movement and posture. They are broadly divided into akinetic and hyperkinetic... (Review)
Review
Movement disorders are a group of neurological conditions characterized by abnormalities of movement and posture. They are broadly divided into akinetic and hyperkinetic syndromes. Until now, no effective symptomatic or disease-modifying therapies have been available. However, since many of these disorders are monogenic or have some well-defined genetic component, they represent strong candidates for antisense oligonucleotide (ASO) therapies. ASO therapies are based on the use of short synthetic single-stranded ASOs that bind to disease-related target RNAs via Watson-Crick base-pairing and pleiotropically modulate their function. With information arising from the RNA sequence alone, it is possible to design ASOs that not only alter the expression levels but also the splicing defects of any protein, far exceeding the intervention repertoire of traditional small molecule approaches. Following the regulatory approval of ASO therapies for spinal muscular atrophy and Duchenne muscular dystrophy in 2016, there has been tremendous momentum in testing such therapies for other neurological disorders. This review article initially focuses on the chemical modifications aimed at improving ASO effectiveness, the mechanisms by which ASOs can interfere with RNA function, delivery systems and pharmacokinetics, and the common set of toxicities associated with their application. It, then, describes the pathophysiology and the latest information on preclinical and clinical trials utilizing ASOs for the treatment of Parkinson's disease, Huntington's disease, and ataxias 1, 2, 3, and 7. It concludes with issues that require special attention to realize the full potential of ASO-based therapies.
Topics: Humans; Huntington Disease; Nervous System Diseases; Oligonucleotides, Antisense; Parkinson Disease
PubMed: 32656818
DOI: 10.1002/med.21706 -
Molecules (Basel, Switzerland) Apr 2017Neuromuscular disorders such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy are neurodegenerative genetic diseases characterized primarily by muscle weakness... (Review)
Review
Neuromuscular disorders such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy are neurodegenerative genetic diseases characterized primarily by muscle weakness and wasting. Until recently there were no effective therapies for these conditions, but antisense oligonucleotides, a new class of synthetic single stranded molecules of nucleic acids, have demonstrated promising experimental results and are at different stages of regulatory approval. The antisense oligonucleotides can modulate the protein expression via targeting hnRNAs or mRNAs and inducing interference with splicing, mRNA degradation, or arrest of translation, finally, resulting in rescue or reduction of the target protein expression. Different classes of antisense oligonucleotides are being tested in several clinical trials, and limitations of their clinical efficacy and toxicity have been reported for some of these compounds, while more encouraging results have supported the development of others. New generation antisense oligonucleotides are also being tested in preclinical models together with specific delivery systems that could allow some of the limitations of current antisense oligonucleotides to be overcome, to improve the cell penetration, to achieve more robust target engagement, and hopefully also be associated with acceptable toxicity. This review article describes the chemical properties and molecular mechanisms of action of the antisense oligonucleotides and the therapeutic implications these compounds have in neuromuscular diseases. Current strategies and carrier systems available for the oligonucleotides delivery will be also described to provide an overview on the past, present and future of these appealing molecules.
Topics: Animals; Biological Transport; Cell-Penetrating Peptides; Clinical Trials as Topic; Drug Evaluation, Preclinical; Gene Transfer Techniques; Genetic Therapy; Humans; Muscular Atrophy, Spinal; Muscular Dystrophy, Duchenne; Neuromuscular Diseases; Oligonucleotides, Antisense; RNA Splicing; RNA, Messenger
PubMed: 28379182
DOI: 10.3390/molecules22040563 -
Cells Oct 2023Antisense oligonucleotide-based (ASO) therapeutics have emerged as a promising strategy for the treatment of human disorders. Charge-neutral PMOs have promising... (Review)
Review
Antisense oligonucleotide-based (ASO) therapeutics have emerged as a promising strategy for the treatment of human disorders. Charge-neutral PMOs have promising biological and pharmacological properties for antisense applications. Despite their great potential, the efficient delivery of these therapeutic agents to target cells remains a major obstacle to their widespread use. Cellular uptake of naked PMO is poor. Cell-penetrating peptides (CPPs) appear as a possibility to increase the cellular uptake and intracellular delivery of oligonucleotide-based drugs. Among these, the DG9 peptide has been identified as a versatile CPP with remarkable potential for enhancing the delivery of ASO-based therapeutics due to its unique structural features. Notably, in the context of phosphorodiamidate morpholino oligomers (PMOs), DG9 has shown promise in enhancing delivery while maintaining a favorable toxicity profile. A few studies have highlighted the potential of DG9-conjugated PMOs in DMD (Duchenne Muscular Dystrophy) and SMA (Spinal Muscular Atrophy), displaying significant exon skipping/inclusion and functional improvements in animal models. The article provides an overview of a detailed understanding of the challenges that ASOs face prior to reaching their targets and continued advances in methods to improve their delivery to target sites and cellular uptake, focusing on DG9, which aims to harness ASOs' full potential in precision medicine.
Topics: Animals; Humans; Oligonucleotides, Antisense; Cell-Penetrating Peptides; Oligonucleotides; Morpholinos; Muscular Dystrophy, Duchenne; Muscular Atrophy, Spinal
PubMed: 37830609
DOI: 10.3390/cells12192395 -
European Journal of Cell Biology Jun 2023Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the... (Review)
Review
Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the death of motor neurons and progressive muscle weakness. SMN1 normally produces an essential protein called SMN. Although humans possess a paralogous gene called SMN2, ∼90% of the SMN it produces is non-functional. This is due to a mutation in SMN2 that causes the skipping of a required exon during splicing of the pre-mRNA. The first treatment for SMA, nusinersen (brand name Spinraza), was approved by the FDA in 2016 and by the EMU in 2017. Nusinersen is an antisense oligonucleotide-based therapy that alters the splicing of SMN2 to make functional full-length SMN protein. Despite the recent advancements in antisense oligonucleotide therapy and SMA treatment development, nusinersen is faced with a multitude of challenges, such as intracellular and systemic delivery. In recent years, the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) in antisense therapy has gained interest. These are antisense oligonucleotides conjugated to cell-penetrating peptides such as Pips and DG9, and they have the potential to address the challenges associated with delivery. This review focuses on the historic milestones, development, current challenges, and future perspectives of antisense therapy for SMA.
Topics: Humans; Oligonucleotides, Antisense; Muscular Atrophy, Spinal; Morpholinos; Motor Neurons; RNA Splicing
PubMed: 37295266
DOI: 10.1016/j.ejcb.2023.151326 -
Annual Review of Pharmacology and... Jan 2021The genetic basis for most inherited neurodegenerative diseases has been identified, yet there are limited disease-modifying therapies for these patients. A new class of... (Review)
Review
The genetic basis for most inherited neurodegenerative diseases has been identified, yet there are limited disease-modifying therapies for these patients. A new class of drugs-antisense oligonucleotides (ASOs)-show promise as a therapeutic platform for treating neurological diseases. ASOs are designed to bind to the RNAs either by promoting degradation of the targeted RNA or by elevating expression by RNA splicing. Intrathecal injection into the cerebral spinal fluid results in broad distribution of antisense drugs and long-term effects. Approval of nusinersen in 2016 demonstrated that effective treatments for neurodegenerative diseases can be identified and that treatments not only slow disease progression but also improve some symptoms. Antisense drugs are currently in development for amyotrophic lateral sclerosis, Huntington's disease, Alzheimer's disease, Parkinson's disease, and Angelman syndrome, and several drugs are in late-stage research for additional neurological diseases. This review highlights the advances in antisense technology as potential treatments for neurological diseases.
Topics: Humans; Neurodegenerative Diseases; Oligonucleotides, Antisense; Parkinson Disease; Pharmaceutical Preparations; RNA
PubMed: 33035446
DOI: 10.1146/annurev-pharmtox-010919-023738 -
Drug Discovery Today Oct 2021Drug properties of antisense oligonucleotides (ASOs) differ significantly from those of traditional small-molecule therapeutics. In this review, we focus on ASO... (Review)
Review
Drug properties of antisense oligonucleotides (ASOs) differ significantly from those of traditional small-molecule therapeutics. In this review, we focus on ASO disposition, mainly as characterized by distribution and biotransformation, of nonconjugated and conjugated ASOs. We introduce ASO chemistry to allow the following in-depth discussion on bioanalytical methods and determination of distribution and elimination kinetics at low concentrations over extended periods of time. The resulting quantitative data on the parent oligonucleotide, and the identification and quantification of formed metabolites define the disposition. Proper quantitative understanding of disposition is pivotal for nonclinical to clinical predictions, supports communication with health agencies, and increases the probability of delivering optimal ASO therapy to patients.
Topics: Animals; Biotransformation; Drug Development; Humans; Oligonucleotides, Antisense; Time Factors; Tissue Distribution
PubMed: 33862193
DOI: 10.1016/j.drudis.2021.04.002 -
Current Opinion in Neurology Oct 2022The development of new therapies has brought spinal muscular atrophy (SMA) into the spotlight. However, this was preceded by a long journey - from the first clinical... (Review)
Review
PURPOSE OF REVIEW
The development of new therapies has brought spinal muscular atrophy (SMA) into the spotlight. However, this was preceded by a long journey - from the first clinical description to the discovery of the genetic cause to molecular mechanisms of RNA and DNA technology.
RECENT FINDINGS
Since 2016, the antisense oligonucleotide nusinersen has been (FDA) approved for the treatment of SMA, followed by the gene replacement therapy onasemnogene abeparvovec-xioi in 2019 and the small-molecule risdiplam in 2020. These drugs, all targeting upregulation of the SMN protein not only showed remarkable effects in clinical trials but also in real-world settings. SMA has been implemented in newborn screening in many countries around the world. SMN-independent strategies targeting skeletal muscle, for example, may play another therapeutic approach in the future.
SUMMARY
This review aims to summarize the major clinical and basic science achievements in the field of SMA.
Topics: Genetic Therapy; Humans; Infant, Newborn; Muscular Atrophy, Spinal; Oligonucleotides, Antisense
PubMed: 35942665
DOI: 10.1097/WCO.0000000000001102 -
Annual Review of Pharmacology and... Jan 2017Recent studies have led to a greater appreciation of the diverse roles RNAs play in maintaining normal cellular function and how they contribute to disease pathology,... (Review)
Review
Recent studies have led to a greater appreciation of the diverse roles RNAs play in maintaining normal cellular function and how they contribute to disease pathology, broadening the number of potential therapeutic targets. Antisense oligonucleotides are the most direct means to target RNA in a selective manner and have become an established platform technology for drug discovery. There are multiple molecular mechanisms by which antisense oligonucleotides can be used to modulate RNAs in cells, including promoting the degradation of the targeted RNA or modulating RNA function without degradation. Antisense drugs utilizing various antisense mechanisms are demonstrating therapeutic potential for the treatment of a broad variety of diseases. This review focuses on some of the advances that have taken place in translating antisense technology from the bench to the clinic.
Topics: Animals; Autoimmune Diseases; Cardiovascular Diseases; Humans; Oligonucleotides, Antisense; RNA Interference; RNA Splicing
PubMed: 27732800
DOI: 10.1146/annurev-pharmtox-010716-104846 -
International Journal of Molecular... Nov 2022Myotonic dystrophy type 1 (DM1) is a dominant genetic disease in which the expansion of long CTG trinucleotides in the 3' UTR of the myotonic dystrophy protein kinase ()... (Review)
Review
Myotonic dystrophy type 1 (DM1) is a dominant genetic disease in which the expansion of long CTG trinucleotides in the 3' UTR of the myotonic dystrophy protein kinase () gene results in toxic RNA gain-of-function and gene mis-splicing affecting mainly the muscles, the heart, and the brain. The CUG-expanded transcripts are a suitable target for the development of antisense oligonucleotide (ASO) therapies. Various chemical modifications of the sugar-phosphate backbone have been reported to significantly enhance the affinity of ASOs for RNA and their resistance to nucleases, making it possible to reverse DM1-like symptoms following systemic administration in different transgenic mouse models. However, specific tissue delivery remains to be improved to achieve significant clinical outcomes in humans. Several strategies, including ASO conjugation to cell-penetrating peptides, fatty acids, or monoclonal antibodies, have recently been shown to improve potency in muscle and cardiac tissues in mice. Moreover, intrathecal administration of ASOs may be an advantageous complementary administration route to bypass the blood-brain barrier and correct defects of the central nervous system in DM1. This review describes the evolution of the chemical design of antisense oligonucleotides targeting CUG-expanded mRNAs and how recent advances in the field may be game-changing by forwarding laboratory findings into clinical research and treatments for DM1 and other microsatellite diseases.
Topics: Mice; Humans; Animals; Myotonic Dystrophy; Myotonin-Protein Kinase; Oligonucleotides, Antisense; Mice, Transgenic; Oligonucleotides; 3' Untranslated Regions; Trinucleotide Repeat Expansion
PubMed: 36362145
DOI: 10.3390/ijms232113359 -
Seminars in Ophthalmology Aug 2021Antisense oligonucleotides (AON) are synthetic single-stranded fragments of nucleic acids that bind to a specific complementary messenger RNA (mRNA) sequence and change...
Antisense oligonucleotides (AON) are synthetic single-stranded fragments of nucleic acids that bind to a specific complementary messenger RNA (mRNA) sequence and change the final gene product. AON were initially approved for treating cytomegalovirus retinitis and have shown promise in treating Mendelian systemic disease. AON are currently being investigated as a treatment modality for many ophthalmic diseases, including inherited retinal disorders (IRD), inflammatory response and wound healing after glaucoma surgery, and macular degeneration. They provide a possible solution to gene therapy for IRD that are not candidates for adeno-associated virus (AAV) delivery. This chapter outlines the historical background of AON and reviews clinical applications and ongoing clinical trials.
Topics: Dependovirus; Genetic Therapy; Humans; Oligonucleotides, Antisense; Retina; Retinal Diseases
PubMed: 34010086
DOI: 10.1080/08820538.2021.1914116