scholarly journals Towards a combined therapy for spinal muscular atrophy based on opposing effects of an antisense oligonucleotide on chromatin and splicing

2021 ◽  
Author(s):  
Luciano E. Marasco ◽  
Gwendal Dujardin ◽  
Rui Sousa-Luís ◽  
Ying Hsiu Liu ◽  
José Stigliano ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
Rna Polymerase Ii ◽  
Antisense Oligonucleotide ◽  
Muscular Atrophy ◽  
Synergistic Effects ◽  
Combined Therapy ◽  
Hdac Inhibitors ◽  
Transcriptional Elongation ◽  
Loss Of Function ◽  
Protein Levels

SummarySpinal Muscular Atrophy (SMA) is a motor-neuron disease caused by loss-of-function mutations of the SMN1 gene. Humans have a paralog, SMN2, whose exon 7 is predominantly skipped, and so it cannot fully compensate for the lack of SMN1. Nusinersen (Spinraza) is a splicing-correcting antisense oligonucleotide drug (ASO) approved for clinical use. Nusinersen targets a splicing silencer located in SMN2 intron 7 pre-mRNA and, by blocking the binding of the splicing repressors hnRNPA1 and A2, it promotes higher E7 inclusion, increasing SMN protein levels. We show here that, by promoting transcriptional elongation, histone deacetylase (HDAC) inhibitors cooperate with a nusinersen-like ASO to upregulate E7 inclusion. Surprisingly, the ASO also elicits the deployment of the silencing histone mark H3K9me2 on the SMN2 gene, creating a roadblock to RNA polymerase II elongation that acts negatively on E7 inclusion. By removing the roadblock, HDAC inhibition counteracts the undesired chromatin effects of the ASO, resulting in higher E7 inclusion. Combined systemic administration of the nusinersen-like ASO and HDAC inhibitors in neonate SMA mice had strong synergistic effects on SMN expression, growth, survival, and neuromuscular function. Thus, we suggest that HDAC inhibitors have the potential to increase the clinical efficacy of nusinersen, and perhaps other splicing-modulatory ASO drugs, without large pleiotropic effects, as assessed by genome-wide analyses.

scholarly journals Rescue of spinal muscular atrophy mouse models with AAV9-Exon-specific U1 snRNA

2019 ◽  
Vol 47 (14) ◽  
pp. 7618-7632 ◽  
Author(s):  
Irving Donadon ◽  
Erica Bussani ◽  
Federico Riccardi ◽  
Danilo Licastro ◽  
Giulia Romano ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
Muscular Atrophy ◽  
Therapeutic Option ◽  
Cell Cycle Control ◽  
Global Gene Expression ◽  
Loss Of Function ◽  
Adeno Associated Virus ◽  
Protein Levels ◽  
Germline Expression ◽  
Smn Protein

AbstractSpinal Muscular Atrophy results from loss-of-function mutations in SMN1 but correcting aberrant splicing of SMN2 offers hope of a cure. However, current splice therapy requires repeated infusions and is expensive. We previously rescued SMA mice by promoting the inclusion of a defective exon in SMN2 with germline expression of Exon-Specific U1 snRNAs (ExspeU1). Here we tested viral delivery of SMN2 ExspeU1s encoded by adeno-associated virus AAV9. Strikingly the virus increased SMN2 exon 7 inclusion and SMN protein levels and rescued the phenotype of mild and severe SMA mice. In the severe mouse, the treatment improved the neuromuscular function and increased the life span from 10 to 219 days. ExspeU1 expression persisted for 1 month and was effective at around one five-hundredth of the concentration of the endogenous U1snRNA. RNA-seq analysis revealed our potential drug rescues aberrant SMA expression and splicing profiles, which are mostly related to DNA damage, cell-cycle control and acute phase response. Vastly overexpressing ExspeU1 more than 100-fold above the therapeutic level in human cells did not significantly alter global gene expression or splicing. These results indicate that AAV-mediated delivery of a modified U1snRNP particle may be a novel therapeutic option against SMA.

scholarly journals Cerebrospinal Fluid Parameters in Antisense Oligonucleotide-Treated Adult 5q-Spinal Muscular Atrophy Patients

2021 ◽  
Vol 11 (3) ◽  
pp. 296
Author(s):  
Lars Hendrik Müschen ◽  
Alma Osmanovic ◽  
Camilla Binz ◽  
Konstantin F. Jendretzky ◽  
Gresa Ranxha ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Spinal Muscular Atrophy ◽  
Total Protein ◽  
Antisense Oligonucleotide ◽  
Muscular Atrophy ◽  
Neurological Diseases ◽  
Clinical Signs ◽  
Central Nervous System Disease ◽  
Oligoclonal Bands ◽  
System Disease

Approval of nusinersen, an intrathecally administered antisense oligonucleotide, for the treatment of 5q-spinal muscular atrophy (SMA) marked the beginning of a new therapeutic era in neurological diseases. Changes in routine cerebrospinal fluid (CSF) parameters under nusinersen have only recently been described in adult SMA patients. We aimed to explore these findings in a real-world setting and to identify clinical and procedure-associated features that might impact CSF parameters. Routinely collected CSF parameters (leukocyte count, lactate, total protein, CSF/serum albumin quotient (QAlbumin), oligoclonal bands) of 28 adult SMA patients were examined for up to 22 months of nusinersen treatment. Total protein and QAlbumin values significantly increased in the first 10 months, independent of the administration procedure. By month 14, no further increases were detected. Two patients developed transient pleocytosis. In two cases, positive oligoclonal bands were found in the beginning and in four patients throughout the whole observation period. No clinical signs of inflammatory central nervous system disease were apparent. Our data confirm elevated CSF total protein and QAlbumin during nusinersen treatment. These alterations may be caused by both repeated lumbar punctures and the interval between procedures rather than by the medication itself. Generally, there were no severe alterations of CSF routine parameters. These results further underline the safety of nusinersen therapy.

SMN mRNA and protein levels in peripheral blood

Neurology ◽  
2006 ◽  
Vol 66 (7) ◽  
pp. 1067-1073 ◽  
Author(s):  
C. J. Sumner ◽  
S. J. Kolb ◽  
G. G. Harmison ◽  
N. O. Jeffries ◽  
K. Schadt ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Spinal Muscular Atrophy ◽  
Disease Severity ◽  
Peripheral Blood ◽  
Muscular Atrophy ◽  
Gene Copy ◽  
Blood Levels ◽  
Type I ◽  
Protein Levels ◽  
Smn Protein

Background: Clinical trials of drugs that increase SMN protein levels in vitro are currently under way in patients with spinal muscular atrophy.Objective: To develop and validate measures of SMN mRNA and protein in peripheral blood and to establish baseline SMN levels in a cohort of controls, carriers, and patients of known genotype, which could be used to follow response to treatment.Methods: SMN1 and SMN2 gene copy numbers were determined in blood samples collected from 86 subjects. Quantitative reverse transcription PCR was used to measure blood levels of SMN mRNA with and without exon 7. A cell immunoassay was used to measure blood levels of SMN protein.Results: Blood levels of SMN mRNA and protein were measured with high reliability. There was little variation in SMN levels in individual subjects over a 5-week period. Levels of exon 7-containing SMN mRNA and SMN protein correlated with SMN1 and SMN2 gene copy number. With the exception of type I SMA, there was no correlation between SMN levels and disease severity.Conclusion: SMN mRNA and protein levels can be reliably measured in the peripheral blood and used during clinical trials in spinal muscular atrophy, but these levels do not necessarily predict disease severity.

scholarly journals Antisense Oligonucleotide Therapies for Neurodegenerative Diseases

2019 ◽  
Vol 42 (1) ◽  
pp. 385-406 ◽  
Author(s):  
C. Frank Bennett ◽  
Adrian R. Krainer ◽  
Don W. Cleveland
Keyword(s):  
Neurodegenerative Diseases ◽  
Spinal Muscular Atrophy ◽  
Antisense Oligonucleotide ◽  
Antisense Oligonucleotides ◽  
Muscular Atrophy ◽  
Neurological Diseases ◽  
Great Promise ◽  
Disease Symptoms ◽  
Therapeutic Platform ◽  
Lateral Sclerosis

Antisense oligonucleotides represent a novel therapeutic platform for the discovery of medicines that have the potential to treat most neurodegenerative diseases. Antisense drugs are currently in development for the treatment of amyotrophic lateral sclerosis, Huntington's disease, and Alzheimer's disease, and multiple research programs are underway for additional neurodegenerative diseases. One antisense drug, nusinersen, has been approved for the treatment of spinal muscular atrophy. Importantly, nusinersen improves disease symptoms when administered to symptomatic patients rather than just slowing the progression of the disease. In addition to the benefit to spinal muscular atrophy patients, there are discoveries from nusinersen that can be applied to other neurological diseases, including method of delivery, doses, tolerability of intrathecally delivered antisense drugs, and the biodistribution of intrathecal dosed antisense drugs. Based in part on the early success of nusinersen, antisense drugs hold great promise as a therapeutic platform for the treatment of neurological diseases.

scholarly journals Temporal and tissue-specific variability of SMN protein levels in mouse models of spinal muscular atrophy

2018 ◽  
Vol 27 (16) ◽  
pp. 2851-2862 ◽  
Author(s):  
Ewout J N Groen ◽  
Elena Perenthaler ◽  
Natalie L Courtney ◽  
Crispin Y Jordan ◽  
Hannah K Shorrock ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
Mouse Models ◽  
Muscular Atrophy ◽  
Tissue Specific ◽  
Protein Levels ◽  
Smn Protein

scholarly journals The Survival of Motor Neurons Protein Determines the Capacity for snRNP Assembly: Biochemical Deficiency in Spinal Muscular Atrophy

2005 ◽  
Vol 25 (13) ◽  
pp. 5543-5551 ◽  
Author(s):  
Lili Wan ◽  
Daniel J. Battle ◽  
Jeongsik Yong ◽  
Amelie K. Gubitz ◽  
Stephen J. Kolb ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Protein Levels ◽  
Small Nuclear Ribonucleoprotein ◽  
Cell Extracts ◽  
Smn Complex ◽  
Survival Of Motor Neurons ◽  
Smn Protein ◽  
Nuclear Ribonucleoprotein

ABSTRACT Reduction of the survival of motor neurons (SMN) protein levels causes the motor neuron degenerative disease spinal muscular atrophy, the severity of which correlates with the extent of reduction in SMN. SMN, together with Gemins 2 to 7, forms a complex that functions in the assembly of small nuclear ribonucleoprotein particles (snRNPs). Complete depletion of the SMN complex from cell extracts abolishes snRNP assembly, the formation of heptameric Sm cores on snRNAs. However, what effect, if any, reduction of SMN protein levels, as occurs in spinal muscular atrophy patients, has on the capacity of cells to produce snRNPs is not known. To address this, we developed a sensitive and quantitative assay for snRNP assembly, the formation of high-salt- and heparin-resistant stable Sm cores, that is strictly dependent on the SMN complex. We show that the extent of Sm core assembly is directly proportional to the amount of SMN protein in cell extracts. Consistent with this, pulse-labeling experiments demonstrate a significant reduction in the rate of snRNP biogenesis in low-SMN cells. Furthermore, extracts of cells from spinal muscular atrophy patients have a lower capacity for snRNP assembly that corresponds directly to the reduced amount of SMN. Thus, SMN determines the capacity for snRNP biogenesis, and our findings provide evidence for a measurable deficiency in a biochemical activity in cells from patients with spinal muscular atrophy.

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