-
Nucleic Acids Research Apr 2023Eighteen nucleic acid therapeutics have been approved for treatment of various diseases in the last 25 years. Their modes of action include antisense oligonucleotides... (Review)
Review
Eighteen nucleic acid therapeutics have been approved for treatment of various diseases in the last 25 years. Their modes of action include antisense oligonucleotides (ASOs), splice-switching oligonucleotides (SSOs), RNA interference (RNAi) and an RNA aptamer against a protein. Among the diseases targeted by this new class of drugs are homozygous familial hypercholesterolemia, spinal muscular atrophy, Duchenne muscular dystrophy, hereditary transthyretin-mediated amyloidosis, familial chylomicronemia syndrome, acute hepatic porphyria, and primary hyperoxaluria. Chemical modification of DNA and RNA was central to making drugs out of oligonucleotides. Oligonucleotide therapeutics brought to market thus far contain just a handful of first- and second-generation modifications, among them 2'-fluoro-RNA, 2'-O-methyl RNA and the phosphorothioates that were introduced over 50 years ago. Two other privileged chemistries are 2'-O-(2-methoxyethyl)-RNA (MOE) and the phosphorodiamidate morpholinos (PMO). Given their importance in imparting oligonucleotides with high target affinity, metabolic stability and favorable pharmacokinetic and -dynamic properties, this article provides a review of these chemistries and their use in nucleic acid therapeutics. Breakthroughs in lipid formulation and GalNAc conjugation of modified oligonucleotides have paved the way to efficient delivery and robust, long-lasting silencing of genes. This review provides an account of the state-of-the-art of targeted oligo delivery to hepatocytes.
Topics: Humans; Morpholinos; Muscular Dystrophy, Duchenne; Oligonucleotides, Antisense; RNA; RNA Interference
PubMed: 36881759
DOI: 10.1093/nar/gkad067 -
Molecules (Basel, Switzerland) Sep 2021Peptide-oligonucleotide conjugates (POCs) represent one of the increasingly successful albeit costly approaches to increasing the cellular uptake, tissue delivery,... (Review)
Review
Peptide-oligonucleotide conjugates (POCs) represent one of the increasingly successful albeit costly approaches to increasing the cellular uptake, tissue delivery, bioavailability, and, thus, overall efficiency of therapeutic nucleic acids, such as, antisense oligonucleotides and small interfering RNAs. This review puts the subject of chemical synthesis of POCs into the wider context of therapeutic oligonucleotides and the problem of nucleic acid drug delivery, cell-penetrating peptide structural types, the mechanisms of their intracellular transport, and the ways of application, which include the formation of non-covalent complexes with oligonucleotides (peptide additives) or covalent conjugation. The main strategies for the synthesis of POCs are viewed in detail, which are conceptually divided into (a) the stepwise solid-phase synthesis approach and (b) post-synthetic conjugation either in solution or on the solid phase, especially by means of various click chemistries. The relative advantages and disadvantages of both strategies are discussed and compared.
Topics: Amino Acid Sequence; CRISPR-Cas Systems; Cell Membrane Permeability; Cell-Penetrating Peptides; Click Chemistry; Delayed-Action Preparations; Drug Liberation; Humans; Nucleic Acids; Oligonucleotides; RNA, Small Interfering; Solid-Phase Synthesis Techniques
PubMed: 34500849
DOI: 10.3390/molecules26175420 -
Expert Opinion on Drug Metabolism &... Nov 2021Antisense oligonucleotides (ASOs) have emerged as a promising novel drug modality that aims to address unmet medical needs. A record of six ASO drugs have been approved... (Review)
Review
INTRODUCTION
Antisense oligonucleotides (ASOs) have emerged as a promising novel drug modality that aims to address unmet medical needs. A record of six ASO drugs have been approved since 2016, and more candidates are in clinical development. ASOs are the most advanced class within the RNA-based therapeutics field.
AREAS COVERED
This review highlights the two major backbones that are currently used to build the most advanced ASO platforms - the phosphorodiamidate morpholino oligomers (PMOs) and the phosphorothioates (PSs). The absorption, distribution, metabolism, and excretion (ADME) properties of the PMO and PS platforms are discussed in detail.
EXPERT OPINION
Understanding the ADME properties of existing ASOs can foster further improvement of this cutting-edge therapy, thereby enabling researchers to safely develop ASO drugs and enhancing their ability to innovate.
ABBREVIATIONS
2'-MOE, 2'-O-methoxyethyl; 2'PS, 2 modified PS; ADME, absorption, distribution, metabolism, and excretion; ASO, antisense oligonucleotide; AUC, area under the curve; BNA, bridged nucleic acid; CPP, cell-penetrating peptide; CMV, cytomegalovirus; CNS, central nervous system; CYP, cytochrome P; DDI, drug-drug interaction; DMD, Duchenne muscular dystrophy; FDA, Food and Drug Administration; GalNAc3, triantennary N-acetyl galactosamine; IT, intrathecal; IV, intravenous; LNA, locked nucleic acid; mRNA, messenger RNA; NA, not applicable; PBPK, physiologically based pharmacokinetics; PD, pharmacodynamic; PK, pharmacokinetic; PMO, phosphorodiamidate morpholino oligomer; PMOplus, PMOs with positionally specific positive molecular charges; PPMO, peptide-conjugated PMO; PS, phosphorothioate; SC, subcutaneous; siRNA, small-interfering RNA; SMA, spinal muscular atrophy.
Topics: Humans; Morpholinos; Muscular Atrophy, Spinal; Muscular Dystrophy, Duchenne; Oligonucleotides, Antisense; Pharmaceutical Preparations; RNA
PubMed: 34643122
DOI: 10.1080/17425255.2021.1992382 -
Continuum (Minneapolis, Minn.) Dec 2019The dystrophinopathies are among the most common neuromuscular conditions, and they include Duchenne and Becker muscular dystrophies. This article reviews the... (Review)
Review
PURPOSE OF REVIEW
The dystrophinopathies are among the most common neuromuscular conditions, and they include Duchenne and Becker muscular dystrophies. This article reviews the epidemiology, clinical manifestations, genetic cause, management, and new and emerging therapies for this condition.
RECENT FINDINGS
New studies have highlighted how oral corticosteroids have changed the natural history of the disease, prolonging ambulation in boys with Duchenne muscular dystrophy and reducing the risk of developing scoliosis and subsequent surgical correction, improving cardiac health, and increasing long-term survival. Additionally, recent publications have provided insights into how newer and emerging treatment options are becoming more common for this condition. With gene therapy being approved in the United States for the severe form, the dystrophinopathies represent model diseases to understand the personalization of genetic treatment.
SUMMARY
Improvement in the standardization of care and the use of oral corticosteroids have increased the life expectancy of patients with dystrophinopathy and changed the natural history of the disease. This article presents a summary of clinical features, diagnostic testing, and new and emerging treatment strategies for the dystrophinopathies.
Topics: Adrenal Cortex Hormones; Child; Child, Preschool; Humans; Immunologic Factors; Male; Morpholinos; Muscular Dystrophy, Duchenne; Pregnenediones
PubMed: 31794463
DOI: 10.1212/CON.0000000000000791 -
American Journal of Human Genetics Oct 2020Congenital anomalies of the kidney and urinary tract (CAKUT) constitute one of the most frequent birth defects and represent the most common cause of chronic kidney...
Congenital anomalies of the kidney and urinary tract (CAKUT) constitute one of the most frequent birth defects and represent the most common cause of chronic kidney disease in the first three decades of life. Despite the discovery of dozens of monogenic causes of CAKUT, most pathogenic pathways remain elusive. We performed whole-exome sequencing (WES) in 551 individuals with CAKUT and identified a heterozygous de novo stop-gain variant in ZMYM2 in two different families with CAKUT. Through collaboration, we identified in total 14 different heterozygous loss-of-function mutations in ZMYM2 in 15 unrelated families. Most mutations occurred de novo, indicating possible interference with reproductive function. Human disease features are replicated in X. tropicalis larvae with morpholino knockdowns, in which expression of truncated ZMYM2 proteins, based on individual mutations, failed to rescue renal and craniofacial defects. Moreover, heterozygous Zmym2-deficient mice recapitulated features of CAKUT with high penetrance. The ZMYM2 protein is a component of a transcriptional corepressor complex recently linked to the silencing of developmentally regulated endogenous retrovirus elements. Using protein-protein interaction assays, we show that ZMYM2 interacts with additional epigenetic silencing complexes, as well as confirming that it binds to FOXP1, a transcription factor that has also been linked to CAKUT. In summary, our findings establish that loss-of-function mutations of ZMYM2, and potentially that of other proteins in its interactome, as causes of human CAKUT, offering new routes for studying the pathogenesis of the disorder.
Topics: Amphibian Proteins; Animals; Case-Control Studies; Child; Child, Preschool; DNA-Binding Proteins; Epigenesis, Genetic; Family; Female; Forkhead Transcription Factors; Heterozygote; Humans; Infant; Larva; Male; Mice; Mice, Knockout; Morpholinos; Mutation; Pedigree; Protein Binding; Repressor Proteins; Transcription Factors; Urinary Tract; Urogenital Abnormalities; Exome Sequencing; Xenopus
PubMed: 32891193
DOI: 10.1016/j.ajhg.2020.08.013 -
Current Pharmaceutical Biotechnology 2022The dramatically increasing levels of antibiotic resistance are being seen worldwide and are a significant threat to public health. Antibiotic and drug resistance is... (Review)
Review
The dramatically increasing levels of antibiotic resistance are being seen worldwide and are a significant threat to public health. Antibiotic and drug resistance is seen in various bacterial species. Antibiotic resistance is associated with increased morbidity and mortality and increased treatment costs. Antisense-related technologies include oligonucleotides that interfere with gene transcription and expression; these oligonucleotides can help treat antibiotic-resistant bacteria. The important oligonucleotides include Peptide Nucleic Acids (PNAs), Phosphorodiamidate Morpholino Oligomers (PPMOs), and Locked Nucleic Acids (LNAs). Typically, the size of these structures (oligonucleotides) is 10 to 20 bases. PNAs, PPMOs, and LNAs are highlighted in this review as targets for genes that cause the gene to be destroyed and impede bacterial growth. These results open a new perspective for therapeutic intervention. Future studies need to examine different aspects of antisense agents, such as the safety, toxicity, and pharmacokinetic properties of antisense agents in clinical treatment.
Topics: Anti-Bacterial Agents; Morpholinos; Peptide Nucleic Acids; Oligonucleotides, Antisense; Bacteria; Oligonucleotides
PubMed: 35034590
DOI: 10.2174/1389201023666220114160216 -
Muscle & Nerve Sep 2021Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene resulting in the absence of dystrophin. Casimersen is a phosphorodiamidate morpholino oligomer... (Randomized Controlled Trial)
Randomized Controlled Trial
Safety, tolerability, and pharmacokinetics of casimersen in patients with Duchenne muscular dystrophy amenable to exon 45 skipping: A randomized, double-blind, placebo-controlled, dose-titration trial.
INTRODUCTION/AIMS
Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene resulting in the absence of dystrophin. Casimersen is a phosphorodiamidate morpholino oligomer designed to bypass frameshift DMD mutations and produce internally truncated, yet functional, dystrophin protein in patients amenable to exon 45 skipping. Our primary study objective was to evaluate safety and tolerability of casimersen; the secondary objective was to characterize the plasma pharmacokinetics.
METHODS
This multicenter, phase 1/2 trial enrolled 12 participants (aged 7-21 years, who had limited ambulation or were nonambulatory) and comprised a 12-week, double-blind dose titration, then an open-label extension for up to 132 weeks. During dose titration, participants were randomized 2:1 to weekly casimersen infusions at escalating doses of 4, 10, 20, and 30 mg/kg (≥2 weeks per dose), or placebo.
RESULTS
Participants received casimersen for a mean 139.6 weeks. Treatment-emergent adverse events (TEAEs) occurred in all casimersen- and placebo-treated participants and were mostly mild (over 91.4%) and unrelated to casimersen or its dose. There were no deaths, dose reductions, abnormalities in laboratory parameters or vital signs, or casimersen-related serious AEs. Casimersen plasma concentration increased with dose and declined similarly for all dose levels over 24 hours postinfusion. All pharmacokinetic parameters were similar at weeks 7 and 60.
DISCUSSION
Casimersen was well tolerated in participants with DMD amenable to exon 45 skipping. Most TEAEs were mild, nonserious, and unrelated to casimersen. Plasma exposure was dose proportional with no suggestion of plasma accumulation. These results support further studies of casimersen in this population.
Topics: Adolescent; Child; Double-Blind Method; Dystrophin; Exons; Humans; Male; Muscular Dystrophy, Duchenne; Mutation; Oligonucleotides; Young Adult
PubMed: 34105177
DOI: 10.1002/mus.27347 -
Cell Stem Cell Dec 2022In aging, skeletal muscle strength and regenerative capacity decline, due in part to functional impairment of muscle stem cells (MuSCs), yet the underlying mechanisms...
In aging, skeletal muscle strength and regenerative capacity decline, due in part to functional impairment of muscle stem cells (MuSCs), yet the underlying mechanisms remain elusive. Here, we capitalize on mass cytometry to identify high CD47 expression as a hallmark of dysfunctional MuSCs (CD47) with impaired regenerative capacity that predominate with aging. The prevalent CD47 MuSC subset suppresses the residual functional CD47 MuSC subset through a paracrine signaling loop, leading to impaired proliferation. We uncover that elevated CD47 levels on aged MuSCs result from increased U1 snRNA expression, which disrupts alternative polyadenylation. The deficit in aged MuSC function in regeneration can be overcome either by morpholino-mediated blockade of CD47 alternative polyadenylation or antibody blockade of thrombospondin-1/CD47 signaling, leading to improved regeneration in aged mice, with therapeutic implications. Our findings highlight a previously unrecognized age-dependent alteration in CD47 levels and function in MuSCs, which underlies reduced muscle repair in aging.
Topics: Animals; Mice; CD47 Antigen; Myoblasts; Muscle, Skeletal; Aging; Disease Progression
PubMed: 36384141
DOI: 10.1016/j.stem.2022.10.009