1
|
Bagga P, Singh S, Ram G, Kapil S, Singh A. Diving into progress: a review on current therapeutic advancements in spinal muscular atrophy. Front Neurol 2024; 15:1368658. [PMID: 38854961 PMCID: PMC11157111 DOI: 10.3389/fneur.2024.1368658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/29/2024] [Indexed: 06/11/2024] Open
Abstract
Spinal muscular atrophy (SMA) is an uncommon disorder associated with genes characterized by the gradual weakening and deterioration of muscles, often leading to substantial disability and premature mortality. Over the past decade, remarkable strides have been made in the field of SMA therapeutics, revolutionizing the landscape of patient care. One pivotal advancement is the development of gene-targeted therapies, such as nusinersen, onasemnogene abeparvovec and risdiplam which have demonstrated unprecedented efficacy in slowing disease progression. These therapies aim to address the root cause of SMA by targeting the survival motor neuron (SMN) gene, effectively restoring deficient SMN protein levels. The advent of these innovative approaches has transformed the prognosis for many SMA patients, offering a glimmer of hope where there was once limited therapeutic recourse. Furthermore, the emergence of small molecule compounds and RNA-targeting strategies has expanded the therapeutic arsenal against SMA. These novel interventions exhibit diverse mechanisms of action, including SMN protein stabilization and modulation of RNA splicing, showcasing the multifaceted nature of SMA treatment research. Collective efforts of pharmaceutical industries, research centers, and patient advocacy groups have played an important role in expediting the translation of scientific discoveries into visible clinical benefits. This review not only highlights the remarkable progress achieved in SMA therapeutics but also generates the ray of hope for the ongoing efforts required to enhance accessibility, optimize treatment strategies, rehabilitation (care and therapies) and ultimately pave the way for an improved quality of life for individuals affected by SMA.
Collapse
Affiliation(s)
- Pankaj Bagga
- School of Bioengineering & Biosciences, Lovely Professional University (LPU), Phagwara, India
| | - Sudhakar Singh
- School of Bioengineering & Biosciences, Lovely Professional University (LPU), Phagwara, India
| | - Gobind Ram
- PG Department of Biotechnology, Layalpur Khalsa College, Jalandhar, India
| | - Subham Kapil
- Department of Zoology, DAV College Jalandhar, Jalandhar, India
| | - Avtar Singh
- School of Electrical Engineering and Computing (SoEEC), Adama Science and Technology University (AS-TU), Adama, Ethiopia
| |
Collapse
|
2
|
Sharifi Z, Taheri M, Fallah MS, Abiri M, Golnabi F, Bagherian H, Zeinali R, Farahzadi H, Alborji M, Tehrani PG, Amini M, Asnavandi S, Hashemi M, Forouzesh F, Zeinali S. Comprehensive Mutation Analysis and Report of 12 Novel Mutations in a Cohort of Patients with Spinal Muscular Atrophy in Iran. J Mol Neurosci 2021; 71:2281-2298. [PMID: 33481221 DOI: 10.1007/s12031-020-01789-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 12/30/2020] [Indexed: 12/17/2022]
Abstract
Spinal muscular atrophies (SMAs) are a heterogeneous group of neuromuscular diseases characterized by loss of motor neurons, muscle weakness, hypotonia and muscle atrophy, with different modes of inheritance; however, the survival motor neuron 1 (SMN1) gene is predominantly involved. The aims of the current study were to clarify the genetic basis of SMA and determine the mutation spectrum of SMN1 and other associated genes, in order to provide molecular information for more accurate diagnosis and future prospects for treatment. We performed a comprehensive analysis of 5q SMA in 1765 individuals including 528 patients from 432 unrelated families with at least one child with suspected clinical presentation of SMA. Copy number variations of the SMN1 and SMN2 genes and linkage analysis were performed using multiplex ligation-dependent probe amplification (MLPA) and short tandem repeat (STR) markers linked to the SMN1 gene. Cases without mutation in the SMA locus on 5q were analyzed for the DNAJB2, IGHMBP2, SIGMAR1 and PLEKHG5 genes using linked STR markers. Sanger sequencing of whole genes was performed for cases with homozygous haplotypes. Whole-genome sequencing (WGS) and whole-exome analysis was conducted for some of the remaining cases. Mutations in the SMN1 gene were identified in 287 (66.43%) families including 269 patients (62.26%) with homozygous deletion of the entire SMN1 gene. Only one of the patients had a homozygous point mutation in the SMN1 gene. Among the remaining families, three families showed mutations in either the DNAJB2, SIGMAR1 or PLEKHG5 genes, which were linked using STR analysis and Sanger sequencing. From 10 families who underwent WGS, we found six homozygous point mutations in six families for either the TNNT1, TPM3, TTN, SACS or COL6A2 genes. Two mutations in the PLA2G6 gene were also found in another patient as compound heterozygous. This rather large cohort allowed us to identify genotype patterns in Iranian 5q SMA patients. The process of identifying 11 mutations (9 novel) in 9 different genes among non-5q SMA patients shows the diversity of genes involved in non-5q SMA in Iranians. Genotyping of patients with SMA is essential for prenatal and preimplantation genetic diagnosis (PGD), and may be very helpful for guiding treatment, with the advent of new, more effective, albeit very expensive, therapies. Also, combining linkage analysis was shown to be beneficial in many ways, including sample authenticity and segregation analysis, and for ruling out maternal cell contamination during prenatal diagnosis (PND).
Collapse
Affiliation(s)
- Zohreh Sharifi
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.,Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Mohammad Taheri
- Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad-Sadegh Fallah
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Maryam Abiri
- Department of Medical Genetics and Molecular Biology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Golnabi
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Hamideh Bagherian
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Razieh Zeinali
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Hossein Farahzadi
- Proteomics Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marjan Alborji
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | | | - Masoume Amini
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Sadaf Asnavandi
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran
| | - Mehrdad Hashemi
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Flora Forouzesh
- Department of Genetics, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Sirous Zeinali
- Dr. Zeinali's Medical Genetics Laboratory, Kawsar Human Genetics Research Center, Tehran, Iran. .,Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
| |
Collapse
|
3
|
Williams SE, Koch KC, Disselhorst-Klug C. Non-invasive assessment of motor unit activation in relation to motor neuron level and lesion location in stroke and spinal muscular atrophy. Clin Biomech (Bristol, Avon) 2020; 78:105053. [PMID: 32563725 DOI: 10.1016/j.clinbiomech.2020.105053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 05/06/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Neuromuscular disorders e.g. spinal muscular atrophy and stroke have a negative impact on functional movement capability. These disorders affect lower and upper motor neurons respectively. METHODS In this study high spatial resolution electromyography was used to record the motor unit activity in 3 groups: healthy subjects, a spinal muscular atrophy group and a stroke group. 7 clinically sensitive parameters were used to analyze the activation patterns of a few motor units. FINDINGS In the case of spinal muscular atrophy there was no effect on motor unit activation but on their number. Stroke was characterized by fewer active motor units and a significantly reduced firing rate with low variability. INTERPRETATION The results suggest, that for stroke, information from the brain is modified thereby resulting in motor units firing at their natural frequency. Thus, high spatial resolution electromyography and the chosen parameters facilitate non-invasive, objective differentiation and analysis of the activation patterns of motor units in neuromuscular disorders.
Collapse
Affiliation(s)
- Sybele E Williams
- Department of Rehabilitation and Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University, 52074 Aachen, Germany.
| | - Kathrin C Koch
- Department of Rehabilitation and Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University, 52074 Aachen, Germany
| | - Catherine Disselhorst-Klug
- Department of Rehabilitation and Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University, 52074 Aachen, Germany
| |
Collapse
|
4
|
Wadman RI, van der Pol WL, Bosboom WMJ, Asselman F, van den Berg LH, Iannaccone ST, Vrancken AFJE. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2020; 1:CD006282. [PMID: 32006461 PMCID: PMC6995983 DOI: 10.1002/14651858.cd006282.pub5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a (point) mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. This is an update of a review first published in 2009 and previously updated in 2011. OBJECTIVES To evaluate if drug treatment is able to slow or arrest the disease progression of SMA types II and III, and to assess if such therapy can be given safely. SEARCH METHODS We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. In October 2018, we also searched two trials registries to identify unpublished trials. SELECTION CRITERIA We sought all randomised or quasi-randomised trials that examined the efficacy of drug treatment for SMA types II and III. Participants had to fulfil the clinical criteria and have a homozygous deletion or hemizygous deletion in combination with a point mutation in the second allele of the SMN1 gene (5q11.2-13.2) confirmed by genetic analysis. The primary outcome measure was change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full-time ventilation and adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1-replacement with viral vectors are out of the scope of this review, but a summary is given in Appendix 1. Drug treatment for SMA type I is the topic of a separate Cochrane Review. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methodology. MAIN RESULTS The review authors found 10 randomised, placebo-controlled trials of treatments for SMA types II and III for inclusion in this review, with 717 participants. We added four of the trials at this update. The trials investigated creatine (55 participants), gabapentin (84 participants), hydroxyurea (57 participants), nusinersen (126 participants), olesoxime (165 participants), phenylbutyrate (107 participants), somatotropin (20 participants), thyrotropin-releasing hormone (TRH) (nine participants), valproic acid (33 participants), and combination therapy with valproic acid and acetyl-L-carnitine (ALC) (61 participants). Treatment duration was from three to 24 months. None of the studies investigated the same treatment and none was completely free of bias. All studies had adequate blinding, sequence generation and reporting of primary outcomes. Based on moderate-certainty evidence, intrathecal nusinersen improved motor function (disability) in children with SMA type II, with a 3.7-point improvement in the nusinersen group on the Hammersmith Functional Motor Scale Expanded (HFMSE; range of possible scores 0 to 66), compared to a 1.9-point decline on the HFMSE in the sham procedure group (P < 0.01; n = 126). On all motor function scales used, higher scores indicate better function. Based on moderate-certainty evidence from two studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: creatine (median change 1 higher, 95% confidence interval (CI) -1 to 2; on the Gross Motor Function Measure (GMFM), scale 0 to 264; n = 40); and combination therapy with valproic acid and carnitine (mean difference (MD) 0.64, 95% CI -1.1 to 2.38; on the Modified Hammersmith Functional Motor Scale (MHFMS), scale 0 to 40; n = 61). Based on low-certainty evidence from other single studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: gabapentin (median change 0 in the gabapentin group and -2 in the placebo group on the SMA Functional Rating Scale (SMAFRS), scale 0 to 50; n = 66); hydroxyurea (MD -1.88, 95% CI -3.89 to 0.13 on the GMFM, scale 0 to 264; n = 57), phenylbutyrate (MD -0.13, 95% CI -0.84 to 0.58 on the Hammersmith Functional Motor Scale (HFMS) scale 0 to 40; n = 90) and monotherapy of valproic acid (MD 0.06, 95% CI -1.32 to 1.44 on SMAFRS, scale 0 to 50; n = 31). Very low-certainty evidence suggested that the following interventions had little or no effect on motor function: olesoxime (MD 2, 95% -0.25 to 4.25 on the Motor Function Measure (MFM) D1 + D2, scale 0 to 75; n = 160) and somatotropin (median change at 3 months 0.25 higher, 95% CI -1 to 2.5 on the HFMSE, scale 0 to 66; n = 19). One small TRH trial did not report effects on motor function and the certainty of evidence for other outcomes from this trial were low or very low. Results of nine completed trials investigating 4-aminopyridine, acetyl-L-carnitine, CK-2127107, hydroxyurea, pyridostigmine, riluzole, RO6885247/RG7800, salbutamol and valproic acid were awaited and not available for analysis at the time of writing. Various trials and studies investigating treatment strategies other than nusinersen (e.g. SMN2-augmentation by small molecules), are currently ongoing. AUTHORS' CONCLUSIONS Nusinersen improves motor function in SMA type II, based on moderate-certainty evidence. Creatine, gabapentin, hydroxyurea, phenylbutyrate, valproic acid and the combination of valproic acid and ALC probably have no clinically important effect on motor function in SMA types II or III (or both) based on low-certainty evidence, and olesoxime and somatropin may also have little to no clinically important effect but evidence was of very low-certainty. One trial of TRH did not measure motor function.
Collapse
Affiliation(s)
- Renske I Wadman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - W Ludo van der Pol
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Wendy MJ Bosboom
- Onze Lieve Vrouwe Gasthuis locatie WestDepartment of NeurologyAmsterdamNetherlands
| | - Fay‐Lynn Asselman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Leonard H van den Berg
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Susan T Iannaccone
- University of Texas Southwestern Medical CenterDepartment of Pediatrics5323 Harry Hines BoulevardDallasTexasUSA75390
| | - Alexander FJE Vrancken
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | | |
Collapse
|
5
|
Wadman RI, van der Pol WL, Bosboom WMJ, Asselman F, van den Berg LH, Iannaccone ST, Vrancken AFJE. Drug treatment for spinal muscular atrophy type I. Cochrane Database Syst Rev 2019; 12:CD006281. [PMID: 31825542 PMCID: PMC6905354 DOI: 10.1002/14651858.cd006281.pub5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a point mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. By definition, children with SMA type I are never able to sit without support and usually die or become ventilator dependent before the age of two years. There have until very recently been no drug treatments to influence the course of SMA. We undertook this updated review to evaluate new evidence on emerging treatments for SMA type I. The review was first published in 2009 and previously updated in 2011. OBJECTIVES To assess the efficacy and safety of any drug therapy designed to slow or arrest progression of spinal muscular atrophy (SMA) type I. SEARCH METHODS We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. We also searched two trials registries to identify unpublished trials (October 2018). SELECTION CRITERIA We sought all randomised controlled trials (RCTs) or quasi-RCTs that examined the efficacy of drug treatment for SMA type I. Included participants had to fulfil clinical criteria and have a genetically confirmed deletion or mutation of the SMN1 gene (5q11.2-13.2). The primary outcome measure was age at death or full-time ventilation. Secondary outcome measures were acquisition of motor milestones, i.e. head control, rolling, sitting or standing, motor milestone response on disability scores within one year after the onset of treatment, and adverse events and serious adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1 gene replacement with viral vectors are out of the scope of this review. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methodology. MAIN RESULTS We identified two RCTs: one trial of intrathecal nusinersen in comparison to a sham (control) procedure in 121 randomised infants with SMA type I, which was newly included at this update, and one small trial comparing riluzole treatment to placebo in 10 children with SMA type I. The RCT of intrathecally-injected nusinersen was stopped early for efficacy (based on a predefined Hammersmith Infant Neurological Examination-Section 2 (HINE-2) response). At the interim analyses after 183 days of treatment, 41% (21/51) of nusinersen-treated infants showed a predefined improvement on HINE-2, compared to 0% (0/27) of participants in the control group. This trial was largely at low risk of bias. Final analyses (ranging from 6 months to 13 months of treatment), showed that fewer participants died or required full-time ventilation (defined as more than 16 hours daily for 21 days or more) in the nusinersen-treated group than the control group (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.32 to 0.89; N = 121; a 47% lower risk; moderate-certainty evidence). A proportion of infants in the nusinersen group and none of 37 infants in the control group achieved motor milestones: 37/73 nusinersen-treated infants (51%) achieved a motor milestone response on HINE-2 (risk ratio (RR) 38.51, 95% CI 2.43 to 610.14; N = 110; moderate-certainty evidence); 16/73 achieved head control (RR 16.95, 95% CI 1.04 to 274.84; moderate-certainty evidence); 6/73 achieved independent sitting (RR 6.68, 95% CI 0.39 to 115.38; moderate-certainty evidence); 7/73 achieved rolling over (RR 7.70, 95% CI 0.45 to 131.29); and 1/73 achieved standing (RR 1.54, 95% CI 0.06 to 36.92; moderate-certainty evidence). Seventy-one per cent of nusinersen-treated infants versus 3% of infants in the control group were responders on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) measure of motor disability (RR 26.36, 95% CI 3.79 to 183.18; N = 110; moderate-certainty evidence). Adverse events and serious adverse events occurred in the majority of infants but were no more frequent in the nusinersen-treated group than the control group (RR 0.99, 95% CI 0.92 to 1.05 and RR 0.70, 95% CI 0.55 to 0.89, respectively; N = 121; moderate-certainty evidence). In the riluzole trial, three of seven children treated with riluzole were still alive at the ages of 30, 48, and 64 months, whereas all three children in the placebo group died. None of the children in the riluzole or placebo group developed the ability to sit, which was the only milestone reported. There were no adverse effects. The certainty of the evidence for all measured outcomes from this study was very low, because the study was too small to detect or rule out an effect, and had serious limitations, including baseline differences. This trial was stopped prematurely because the pharmaceutical company withdrew funding. Various trials and studies investigating treatment strategies other than nusinersen, such as SMN2 augmentation by small molecules, are ongoing. AUTHORS' CONCLUSIONS Based on the very limited evidence currently available regarding drug treatments for SMA type 1, intrathecal nusinersen probably prolongs ventilation-free and overall survival in infants with SMA type I. It is also probable that a greater proportion of infants treated with nusinersen than with a sham procedure achieve motor milestones and can be classed as responders to treatment on clinical assessments (HINE-2 and CHOP INTEND). The proportion of children experiencing adverse events and serious adverse events on nusinersen is no higher with nusinersen treatment than with a sham procedure, based on evidence of moderate certainty. It is uncertain whether riluzole has any effect in patients with SMA type I, based on the limited available evidence. Future trials could provide more high-certainty, longer-term evidence to confirm this result, or focus on comparing new treatments to nusinersen or evaluate them as an add-on therapy to nusinersen.
Collapse
Affiliation(s)
- Renske I Wadman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - W Ludo van der Pol
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Wendy MJ Bosboom
- Onze Lieve Vrouwe Gasthuis locatie WestDepartment of NeurologyAmsterdamNetherlands
| | - Fay‐Lynn Asselman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Leonard H van den Berg
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Susan T Iannaccone
- University of Texas Southwestern Medical CenterDepartment of Pediatrics5323 Harry Hines BoulevardDallasTexasUSA75390
| | - Alexander FJE Vrancken
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | | |
Collapse
|
6
|
Recessive mutations in muscle-specific isoforms of FXR1 cause congenital multi-minicore myopathy. Nat Commun 2019; 10:797. [PMID: 30770808 PMCID: PMC6377633 DOI: 10.1038/s41467-019-08548-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 01/18/2019] [Indexed: 02/06/2023] Open
Abstract
FXR1 is an alternatively spliced gene that encodes RNA binding proteins (FXR1P) involved in muscle development. In contrast to other tissues, cardiac and skeletal muscle express two FXR1P isoforms that incorporate an additional exon-15. We report that recessive mutations in this particular exon of FXR1 cause congenital multi-minicore myopathy in humans and mice. Additionally, we show that while Myf5-dependent depletion of all FXR1P isoforms is neonatal lethal, mice carrying mutations in exon-15 display non-lethal myopathies which vary in severity depending on the specific effect of each mutation on the protein.
Collapse
|
7
|
Kletzl H, Marquet A, Günther A, Tang W, Heuberger J, Groeneveld GJ, Birkhoff W, Mercuri E, Lochmüller H, Wood C, Fischer D, Gerlach I, Heinig K, Bugawan T, Dziadek S, Kinch R, Czech C, Khwaja O. The oral splicing modifier RG7800 increases full length survival of motor neuron 2 mRNA and survival of motor neuron protein: Results from trials in healthy adults and patients with spinal muscular atrophy. Neuromuscul Disord 2018; 29:21-29. [PMID: 30553700 DOI: 10.1016/j.nmd.2018.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/16/2018] [Accepted: 10/24/2018] [Indexed: 11/15/2022]
Abstract
Spinal muscular atrophy (SMA) is a rare genetic and progressively debilitating neuromuscular disease. It is the leading genetic cause of death among infants. In SMA, low levels of survival of motor neuron (SMN) protein lead to motor neuron death and muscle atrophy as the SMN protein is critical to motor neuron survival. SMA is caused by mutations in, or deletion of, the SMN1 gene. A second SMN gene, SMN2, produces only low levels of functional SMN protein due to alternative splicing which excludes exon 7 from most transcripts, generating truncated, rapidly degraded SMN protein. Patients with SMA rely on limited expression of functional SMN full-length protein from the SMN2 gene, but insufficient levels are generated. RG7800 is an oral, selective SMN2 splicing modifier designed to modulate alternative splicing of SMN2 to increase the levels of functional SMN protein. In two trials, oral administration of RG7800 increased in blood full-length SMN2 mRNA expression in healthy adults and SMN protein levels in SMA patients by up to two-fold, which is expected to provide clinical benefit.
Collapse
Affiliation(s)
- Heidemarie Kletzl
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland.
| | - Anne Marquet
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Andreas Günther
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Wakana Tang
- Research, Genomics & Oncology, Roche Molecular Systems, Inc., Pleasanton, USA
| | | | | | | | | | - Hanns Lochmüller
- Medical Center-University of Freiburg, Freiburg, Germany; Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne, UK; Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada and Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
| | - Claire Wood
- John Walton Muscular Dystrophy Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | - Dirk Fischer
- Universitäts-Kinderspital beider Basel, Basel, Switzerland; University Clinic of Internal Medicine, Kantonsspital Baselland, Bruderholz, Switzerland
| | - Irene Gerlach
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Katja Heinig
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Teodorica Bugawan
- Research, Genomics & Oncology, Roche Molecular Systems, Inc., Pleasanton, USA
| | - Sebastian Dziadek
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Russell Kinch
- Roche Innovation Center, Hoffmann-La Roche Ltd., Welwyn, UK
| | - Christian Czech
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Omar Khwaja
- Roche Innovation Center, Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| |
Collapse
|
8
|
Raimer AC, Gray KM, Matera AG. SMN - A chaperone for nuclear RNP social occasions? RNA Biol 2017; 14:701-711. [PMID: 27648855 PMCID: PMC5519234 DOI: 10.1080/15476286.2016.1236168] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 12/24/2022] Open
Abstract
Survival Motor Neuron (SMN) protein localizes to both the nucleus and the cytoplasm. Cytoplasmic SMN is diffusely localized in large oligomeric complexes with core member proteins, called Gemins. Biochemical and cell biological studies have demonstrated that the SMN complex is required for the cytoplasmic assembly and nuclear transport of Sm-class ribonucleoproteins (RNPs). Nuclear SMN accumulates with spliceosomal small nuclear (sn)RNPs in Cajal bodies, sub-domains involved in multiple facets of snRNP maturation. Thus, the SMN complex forms stable associations with both nuclear and cytoplasmic snRNPs, and plays a critical role in their biogenesis. In this review, we focus on potential functions of the nuclear SMN complex, with particular emphasis on its role within the Cajal body.
Collapse
Affiliation(s)
- Amanda C. Raimer
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kelsey M. Gray
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
9
|
LoMauro A, Aliverti A, Mastella C, Arnoldi MT, Banfi P, Baranello G. Spontaneous Breathing Pattern as Respiratory Functional Outcome in Children with Spinal Muscular Atrophy (SMA). PLoS One 2016; 11:e0165818. [PMID: 27820869 PMCID: PMC5098831 DOI: 10.1371/journal.pone.0165818] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/18/2016] [Indexed: 12/21/2022] Open
Abstract
Introduction SMA is characterised by progressive motor and respiratory muscle weakness. We aimed to verify if in SMA children 1)each form is characterized by specific ventilatory and thoraco-abdominal pattern(VTAp) during quiet breathing(QB); 2)VTAp is affected by salbutamol therapy, currently suggested as standard treatment, or by the natural history(NH) of SMA; 3)the severity of global motor impairment linearly correlates with VTAp. Materials and methods VTAp was analysed on 32 SMA type I (SMA1,the most severe form), 51 type II (SMA2,the moderate), 8 type III (SMA3,the mildest) and 20 healthy (HC) using opto-electronic plethysmography. Spirometry, cough and motor function were measured in a subgroup of patients. Results In SMA1, a normal ventilation is obtained in supine position by rapid and shallow breathing with paradoxical ribcage motion. In SMA2, ventilation is within a normal range in seated position due to an increased respiratory rate(p<0.05) with reduced tidal volume(p<0.05) secondary to a poor contribution of pulmonary ribcage(%ΔVRC,P, p<0.001). Salbutamol therapy had no effect on VTAp during QB(p>0.05) while tachypnea occurred in type I NH. A linear correlation(p<0.001) was found between motor function scales and VTAp. Conclusion A negative or reduced %ΔVRC,P, indicative of ribcage muscle weakness, is a distinctive feature of SMA1 and SMA2 since infancy. Its quantitative assessment represents a non-invasive, non-volitional index that can be obtained in all children, even uncollaborative, and provides useful information on the action of ribcage muscles that are known to be affected by the disease.Low values of motor function scales indicate impairment of motor but also of respiratory function.
Collapse
Affiliation(s)
- A. LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano, Italy
- * E-mail:
| | - A. Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano, Italy
| | - C. Mastella
- S.A.PRE., Ospedale Policlinico Maggiore Mangiagalli, and Regina Elena Foundation, Milan, Italy
| | - M. T. Arnoldi
- Developmental Neurology Unit, Carlo Besta Neurological Research Institute Foundation, Milan, Italy
| | - P. Banfi
- Pulmonary Rehabilitation Fondazione Don Carlo Gnocchi, Milan, Italy
| | - G. Baranello
- Developmental Neurology Unit, Carlo Besta Neurological Research Institute Foundation, Milan, Italy
| |
Collapse
|
10
|
Effect of combined systemic and local morpholino treatment on the spinal muscular atrophy Δ7 mouse model phenotype. Clin Ther 2016; 36:340-56.e5. [PMID: 24636820 DOI: 10.1016/j.clinthera.2014.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/22/2014] [Accepted: 02/07/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a fatal motor neuron disease of childhood that is caused by mutations in the SMN1 gene. Currently, no effective treatment is available. One possible therapeutic approach is the use of antisense oligos (ASOs) to redirect the splicing of the paralogous gene SMN2, thus increasing functional SMN protein production. Various ASOs with different chemical properties are suitable for these applications, including a morpholino oligomer (MO) variant with a particularly excellent safety and efficacy profile. OBJECTIVE We investigated a 25-nt MO sequence targeting the negative intronic splicing silencer (ISS-N1) 10 to 34 region. METHODS We administered a 25-nt MO sequence against the ISS-N1 region of SMN2 (HSMN2Ex7D[-10-34]) in the SMAΔ7 mouse model and evaluated the effect and neuropathologic phenotype. We tested different concentrations (from 2 to 24 nM) and delivery protocols (intracerebroventricular injection, systemic injection, or both). We evaluated the treatment efficacy regarding SMN levels, survival, neuromuscular phenotype, and neuropathologic features. RESULTS We found that a 25-nt MO sequence against the ISS-N1 region of SMN2 (HSMN2Ex7D[-10-34]) exhibited superior efficacy in transgenic SMAΔ7 mice compared with previously described sequences. In our experiments, the combination of local and systemic administration of MO (bare or conjugated to octaguanidine) was the most effective approach for increasing full-length SMN expression, leading to robust improvement in neuropathologic features and survival. Moreover, we found that several small nuclear RNAs were deregulated in SMA mice and that their levels were restored by MO treatment. CONCLUSION These results indicate that MO-mediated SMA therapy is efficacious and can result in phenotypic rescue, providing important insights for further development of ASO-based therapeutic strategies in SMA patients.
Collapse
|
11
|
Cherry JJ, Kobayashi DT, Lynes MM, Naryshkin NN, Tiziano FD, Zaworski PG, Rubin LL, Jarecki J. Assays for the identification and prioritization of drug candidates for spinal muscular atrophy. Assay Drug Dev Technol 2015; 12:315-41. [PMID: 25147906 DOI: 10.1089/adt.2014.587] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder resulting in degeneration of α-motor neurons of the anterior horn and proximal muscle weakness. It is the leading cause of genetic mortality in children younger than 2 years. It affects ∼1 in 11,000 live births. In 95% of cases, SMA is caused by homozygous deletion of the SMN1 gene. In addition, all patients possess at least one copy of an almost identical gene called SMN2. A single point mutation in exon 7 of the SMN2 gene results in the production of low levels of full-length survival of motor neuron (SMN) protein at amounts insufficient to compensate for the loss of the SMN1 gene. Although no drug treatments are available for SMA, a number of drug discovery and development programs are ongoing, with several currently in clinical trials. This review describes the assays used to identify candidate drugs for SMA that modulate SMN2 gene expression by various means. Specifically, it discusses the use of high-throughput screening to identify candidate molecules from primary screens, as well as the technical aspects of a number of widely used secondary assays to assess SMN messenger ribonucleic acid (mRNA) and protein expression, localization, and function. Finally, it describes the process of iterative drug optimization utilized during preclinical SMA drug development to identify clinical candidates for testing in human clinical trials.
Collapse
|
12
|
Naryshkin NA, Weetall M, Dakka A, Narasimhan J, Zhao X, Feng Z, Ling KKY, Karp GM, Qi H, Woll MG, Chen G, Zhang N, Gabbeta V, Vazirani P, Bhattacharyya A, Furia B, Risher N, Sheedy J, Kong R, Ma J, Turpoff A, Lee CS, Zhang X, Moon YC, Trifillis P, Welch EM, Colacino JM, Babiak J, Almstead NG, Peltz SW, Eng LA, Chen KS, Mull JL, Lynes MS, Rubin LL, Fontoura P, Santarelli L, Haehnke D, McCarthy KD, Schmucki R, Ebeling M, Sivaramakrishnan M, Ko CP, Paushkin SV, Ratni H, Gerlach I, Ghosh A, Metzger F. Motor neuron disease. SMN2 splicing modifiers improve motor function and longevity in mice with spinal muscular atrophy. Science 2014; 345:688-93. [PMID: 25104390 DOI: 10.1126/science.1250127] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spinal muscular atrophy (SMA) is a genetic disease caused by mutation or deletion of the survival of motor neuron 1 (SMN1) gene. A paralogous gene in humans, SMN2, produces low, insufficient levels of functional SMN protein due to alternative splicing that truncates the transcript. The decreased levels of SMN protein lead to progressive neuromuscular degeneration and high rates of mortality. Through chemical screening and optimization, we identified orally available small molecules that shift the balance of SMN2 splicing toward the production of full-length SMN2 messenger RNA with high selectivity. Administration of these compounds to Δ7 mice, a model of severe SMA, led to an increase in SMN protein levels, improvement of motor function, and protection of the neuromuscular circuit. These compounds also extended the life span of the mice. Selective SMN2 splicing modifiers may have therapeutic potential for patients with SMA.
Collapse
Affiliation(s)
| | - Marla Weetall
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Amal Dakka
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jana Narasimhan
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Xin Zhao
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Zhihua Feng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Karen K Y Ling
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Gary M Karp
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Hongyan Qi
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Matthew G Woll
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Guangming Chen
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Nanjing Zhang
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Priya Vazirani
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Bansri Furia
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Nicole Risher
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Josephine Sheedy
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Ronald Kong
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Jiyuan Ma
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Anthony Turpoff
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Chang-Sun Lee
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Xiaoyan Zhang
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Young-Choon Moon
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | | | - Ellen M Welch
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Joseph M Colacino
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - John Babiak
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Neil G Almstead
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA
| | - Stuart W Peltz
- PTC Therapeutics, 100 Corporate Court, South Plainfield, NJ 07080, USA.
| | - Loren A Eng
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Karen S Chen
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Jesse L Mull
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Maureen S Lynes
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Lee L Rubin
- Department of Stem Cell and Regenerative Biology and the Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Paulo Fontoura
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Luca Santarelli
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Daniel Haehnke
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | | | - Roland Schmucki
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Martin Ebeling
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Manaswini Sivaramakrishnan
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Chien-Ping Ko
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sergey V Paushkin
- SMA Foundation, 888 Seventh Avenue, Suite 400, New York, NY 10019, USA
| | - Hasane Ratni
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Irene Gerlach
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Anirvan Ghosh
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Friedrich Metzger
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland.
| |
Collapse
|
13
|
Wynne GM, Russell AJ. Drug Discovery Approaches for Rare Neuromuscular Diseases. ORPHAN DRUGS AND RARE DISEASES 2014. [DOI: 10.1039/9781782624202-00257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rare neuromuscular diseases encompass many diverse and debilitating musculoskeletal disorders, ranging from ultra-orphan conditions that affect only a few families, to the so-called ‘common’ orphan diseases like Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), which affect several thousand individuals worldwide. Increasingly, pharmaceutical and biotechnology companies, in an effort to improve productivity and rebuild dwindling pipelines, are shifting their business models away from the formerly popular ‘blockbuster’ strategy, with rare diseases being an area of increased focus in recent years. As a consequence of this paradigm shift, coupled with high-profile campaigns by not-for-profit organisations and patient advocacy groups, rare neuromuscular diseases are attracting considerable attention as new therapeutic areas for improved drug therapy. Much pioneering work has taken place to elucidate the underlying pathological mechanisms of many rare neuromuscular diseases. This, in conjunction with the availability of new screening technologies, has inspired the development of several truly innovative therapeutic strategies aimed at correcting the underlying pathology. A survey of medicinal chemistry approaches and the resulting clinical progress for new therapeutic agents targeting this devastating class of degenerative diseases is presented, using DMD and SMA as examples. Complementary strategies using small-molecule drugs and biological agents are included.
Collapse
Affiliation(s)
- Graham M. Wynne
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Angela J. Russell
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| |
Collapse
|
14
|
Passini MA, Bu J, Richards AM, Treleaven CM, Sullivan JA, O'Riordan CR, Scaria A, Kells AP, Samaranch L, San Sebastian W, Federici T, Fiandaca MS, Boulis NM, Bankiewicz KS, Shihabuddin LS, Cheng SH. Translational fidelity of intrathecal delivery of self-complementary AAV9-survival motor neuron 1 for spinal muscular atrophy. Hum Gene Ther 2014; 25:619-30. [PMID: 24617515 DOI: 10.1089/hum.2014.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by mutations in survival motor neuron 1 (SMN1). Previously, we showed that central nervous system (CNS) delivery of an adeno-associated viral (AAV) vector encoding SMN1 produced significant improvements in survival in a mouse model of SMA. Here, we performed a dose-response study in SMA mice to determine the levels of SMN in the spinal cord necessary for efficacy, and measured the efficiency of motor neuron transduction in the spinal cord after intrathecal delivery in pigs and nonhuman primates (NHPs). CNS injections of 5e10, 1e10, and 1e9 genome copies (gc) of self-complementary AAV9 (scAAV9)-hSMN1 into SMA mice extended their survival from 17 to 153, 70, and 18 days, respectively. Spinal cords treated with 5e10, 1e10, and 1e9 gc showed that 70-170%, 30-100%, and 10-20% of wild-type levels of SMN were attained, respectively. Furthermore, detectable SMN expression in a minimum of 30% motor neurons correlated with efficacy. A comprehensive analysis showed that intrathecal delivery of 2.5e13 gc of scAAV9-GFP transduced 25-75% of the spinal cord motor neurons in NHPs. Thus, the extent of gene expression in motor neurons necessary to confer efficacy in SMA mice could be obtained in large-animal models, justifying the continual development of gene therapy for SMA.
Collapse
Affiliation(s)
- Marco A Passini
- 1 Rare Diseases Science, Genzyme, a Sanofi Company , Framingham, MA 01701
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Infantile spinale Muskelatrophie: mehr als eine Motoneuronerkrankung? MED GENET-BERLIN 2013. [DOI: 10.1007/s11825-013-0398-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Zusammenfassung
Die infantile spinale Muskelatrophie (SMA) – bedingt durch homozygote Mutationen im Survival-motor-neuron-1(SMN1)-Gen – ist durch eine Degeneration von motorischen Neuronen im Vorderhorn des Rückenmarks und im Hirnstamm charakterisiert. Die Folge eines SMN-Proteinmangels ist eine progrediente Muskelatrophie mit proximal betonten Lähmungen der Willkürmuskulatur und motorischen Hirnnervenausfällen. In den letzten Jahren mehren sich klinische Beobachtungen und Berichte von Tiermodellen, dass eine SMN-Proteinreduktion zusätzlich zu unterschiedlichen Funktionsstörungen anderer Organsysteme führt. Diese betreffen insbesondere das periphere, zentrale und autonome Nervensystem, die Entwicklung des Herzes, die Funktion des Verdauungstrakts und metabolische Veränderungen. Um sinnvolle und effiziente Therapiestrategien zu entwickeln und um weiteren Komplikationen begegnen zu können, die sich z. B. bei einer längeren Überlebensdauer v. a. von schwer betroffenen Patienten ergeben können, ist es erforderlich, dass jede mögliche Organpathologie systematisch untersucht wird. Der Vergleich mit SMA-Mausmodellen ist hierfür außerordentlich hilfreich, wenn auch die phänotypischen Auswirkungen nicht vollständig auf den Menschen übertragbar sind.
Collapse
|
16
|
Lunke S, El-Osta A. Applicability of histone deacetylase inhibition for the treatment of spinal muscular atrophy. Neurotherapeutics 2013; 10:677-87. [PMID: 23996601 PMCID: PMC3805858 DOI: 10.1007/s13311-013-0209-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spinal muscular atrophy (SMA), a neurodegenerative disease with potentially devastating and even deadly effects on affected individuals, was first described in the late nineteenth century. Although the survival of motor neuron (SMN) gene was identified nearly 2 decades ago to be causative of the disease, neither an effective treatment nor a cure are currently available. Yet efforts are on-going to test a multitude of treatment strategies with the potential to alleviate disease symptoms in human and clinical trials. Among the most studied compounds for the treatment of SMA are histone deacetylase inhibitors. Several of these epigenetic modifiers have been shown to increase expression of the crucial SMN gene in vitro and in vivo, an effect linked to increased histone acetylation and remodeling of the chromatin landscape surrounding the SMN gene promoter. Here, we review the history and current state of use of histone deacetylase inhibitors in SMA, as well as the success of clinical trials investigating the clinical applicability of these epigenetic modifiers in SMA treatment.
Collapse
Affiliation(s)
- Sebastian Lunke
- />Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC 3004 Australia
- />Translational Genomics Laboratory, Centre for Translational Pathology, Department of Pathology, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Assam El-Osta
- />Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC 3004 Australia
- />Epigenomics Profiling Facility, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct, Melbourne, VIC Australia
- />Department of Pathology, The University of Melbourne, Melbourne, VIC Australia
- />Faculty of Medicine, Monash University, Monash, VIC Australia
| |
Collapse
|
17
|
Abstract
UNLABELLED Spinal muscle atrophy (SMA) is autosomal recessive and one of the most common inherited lethal diseases in childhood. The spectrum of symptoms of SMA is continuous and varies from neonatal death to progressive symmetrical muscle weakness first appearing in adulthood. The disease is produced by degeneration of spinal motor neurons and can be described in three or more categories: SMA I with onset of symptoms before 6 months of age; SMAII with onset between 6 and 18 months and SMA III, which presents later in childhood. Genetics: The disease is in more than 95% of cases caused by a homozygous deletion in survival motor neuron gene 1 (SMN1). PATHOPHYSIOLOGY The loss of full-length functioning SMN protein leads to a degeneration of anterior spinal motor neurons which causes muscle weakness. Anesthetic risks: Airway: Tracheal intubation can be difficult. Respiration: Infants with SMA I almost always need postoperative respiratory support. Patients with SMA II sometimes need support, while SMA III patients seldom need support. Circulation: Circulatory problems during anesthesia are rare. Anesthetic drugs: Neuromuscular blockers: Patients with SMA may display increased sensitivity to and prolonged effect of nondepolarizing neuromuscular blockers. Intubation without muscle relaxation should be considered. Succinylcholine should be avoided. Opioids: These should be titrated carefully. Anesthetic techniques: All types of anesthetic technique have been used. Although none is absolutely contraindicated, none is perfect: anesthesia must be individualized. CONCLUSION The perioperative risks can be considerable and are mainly related to the respiratory system, from respiratory failure to difficult/impossible intubation.
Collapse
Affiliation(s)
- Gunilla Islander
- Department of Intensive and Perioperative Care, Skåne University Hospital, Lund, Sweden.
| |
Collapse
|
18
|
Seo J, Howell MD, Singh NN, Singh RN. Spinal muscular atrophy: an update on therapeutic progress. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2180-90. [PMID: 23994186 DOI: 10.1016/j.bbadis.2013.08.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/27/2013] [Accepted: 08/14/2013] [Indexed: 12/24/2022]
Abstract
Humans have two nearly identical copies of survival motor neuron gene: SMN1 and SMN2. Deletion or mutation of SMN1 combined with the inability of SMN2 to compensate for the loss of SMN1 results in spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA affects 1 in ~6000 live births, a frequency much higher than in several genetic diseases. The major known defect of SMN2 is the predominant exon 7 skipping that leads to production of a truncated protein (SMNΔ7), which is unstable. Therefore, SMA has emerged as a model genetic disorder in which almost the entire disease population could be linked to the aberrant splicing of a single exon (i.e. SMN2 exon 7). Diverse treatment strategies aimed at improving the function of SMN2 have been envisioned. These strategies include, but are not limited to, manipulation of transcription, correction of aberrant splicing and stabilization of mRNA, SMN and SMNΔ7. This review summarizes up to date progress and promise of various in vivo studies reported for the treatment of SMA.
Collapse
Affiliation(s)
- Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | | | | | | |
Collapse
|
19
|
Shababi M, Lorson CL, Rudnik-Schöneborn SS. Spinal muscular atrophy: a motor neuron disorder or a multi-organ disease? J Anat 2013; 224:15-28. [PMID: 23876144 DOI: 10.1111/joa.12083] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2013] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disorder that is the leading genetic cause of infantile death. SMA is characterized by loss of motor neurons in the ventral horn of the spinal cord, leading to weakness and muscle atrophy. SMA occurs as a result of homozygous deletion or mutations in Survival Motor Neuron-1 (SMN1). Loss of SMN1 leads to a dramatic reduction in SMN protein, which is essential for motor neuron survival. SMA disease severity ranges from extremely severe to a relatively mild adult onset form of proximal muscle atrophy. Severe SMA patients typically die mostly within months or a few years as a consequence of respiratory insufficiency and bulbar paralysis. SMA is widely known as a motor neuron disease; however, there are numerous clinical reports indicating the involvement of additional peripheral organs contributing to the complete picture of the disease in severe cases. In this review, we have compiled clinical and experimental reports that demonstrate the association between the loss of SMN and peripheral organ deficiency and malfunction. Whether defective peripheral organs are a consequence of neuronal damage/muscle atrophy or a direct result of SMN loss will be discussed.
Collapse
Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, USA
| | | | | |
Collapse
|
20
|
Cobb MS, Rose FF, Rindt H, Glascock JJ, Shababi M, Miller MR, Osman EY, Yen PF, Garcia ML, Martin BR, Wetz MJ, Mazzasette C, Feng Z, Ko CP, Lorson CL. Development and characterization of an SMN2-based intermediate mouse model of Spinal Muscular Atrophy. Hum Mol Genet 2013; 22:1843-55. [PMID: 23390132 DOI: 10.1093/hmg/ddt037] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is due to the loss of the survival motor neuron gene 1 (SMN1), resulting in motor neuron (MN) degeneration, muscle atrophy and loss of motor function. While SMN2 encodes a protein identical to SMN1, a single nucleotide difference in exon 7 causes most of the SMN2-derived transcripts to be alternatively spliced resulting in a truncated and unstable protein (SMNΔ7). SMA patients retain at least one SMN2 copy, making it an important target for therapeutics. Many of the existing SMA models are very severe, with animals typically living less than 2 weeks. Here, we present a novel intermediate mouse model of SMA based upon the human genomic SMN2 gene. Genetically, this model is similar to the well-characterized SMNΔ7 model; however, we have manipulated the SMNΔ7 transgene to encode a modestly more functional protein referred to as SMN read-through (SMN(RT)). By introducing the SMN(RT) transgene onto the background of a severe mouse model of SMA (SMN2(+/+);Smn(-/-)), disease severity was significantly decreased based upon a battery of phenotypic parameters, including MN pathology and a significant extension in survival. Importantly, there is not a full phenotypic correction, allowing for the examination of a broad range of therapeutics, including SMN2-dependent and SMN-independent pathways. This novel animal model serves as an important biological and therapeutic model for less severe forms of SMA and provides an in vivo validation of the SMN(RT) protein.
Collapse
Affiliation(s)
- Melissa S Cobb
- Department of Veterinary Pathobiology, Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Lorson MA, Lorson CL. SMN-inducing compounds for the treatment of spinal muscular atrophy. Future Med Chem 2012; 4:2067-84. [PMID: 23157239 PMCID: PMC3589915 DOI: 10.4155/fmc.12.131] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality. A neurodegenerative disease, it is caused by loss of SMN1, although low, but essential, levels of SMN protein are produced by the nearly identical gene SMN2. While no effective treatment or therapy currently exists, a new wave of therapeutics has rapidly progressed from cell-based and preclinical animal models to the point where clinical trials have initiated for SMA-specific compounds. There are several reasons why SMA has moved relatively rapidly towards novel therapeutics, including: SMA is monogenic; the molecular understanding of SMN gene regulation has been building for nearly 20 years; and all SMA patients retain one or more copies of SMN2 that produces low levels of full-length, fully functional SMN protein. This review primarily focuses upon the biology behind the disease and examines SMN1- and SMN2-targeted therapeutics.
Collapse
Affiliation(s)
- Monique A Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, Room 440C, University of Missouri, MO 65211 USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Bond Life Sciences Center, Room 471G, University of Missouri, Columbia, MO 65211, USA
- Department of Molecular Microbiology & Immunology, University of Missouri, MO, USA
| |
Collapse
|
22
|
Murdocca M, Malgieri A, Luchetti A, Saieva L, Dobrowolny G, de Leonibus E, Filareto A, Quitadamo MC, Novelli G, Musarò A, Sangiuolo F. IPLEX administration improves motor neuron survival and ameliorates motor functions in a severe mouse model of spinal muscular atrophy. Mol Med 2012; 18:1076-85. [PMID: 22669476 DOI: 10.2119/molmed.2012.00056] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 05/22/2012] [Indexed: 11/06/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neurodegenerative disorder and the first genetic cause of death in childhood. SMA is caused by low levels of survival motor neuron (SMN) protein that induce selective loss of α-motor neurons (MNs) in the spinal cord, resulting in progressive muscle atrophy and consequent respiratory failure. To date, no effective treatment is available to counteract the course of the disease. Among the different therapeutic strategies with potential clinical applications, the evaluation of trophic and/or protective agents able to antagonize MNs degeneration represents an attractive opportunity to develop valid therapies. Here we investigated the effects of IPLEX (recombinant human insulinlike growth factor 1 [rhIGF-1] complexed with recombinant human IGF-1 binding protein 3 [rhIGFBP-3]) on a severe mouse model of SMA. Interestingly, molecular and biochemical analyses of IGF-1 carried out in SMA mice before drug administration revealed marked reductions of IGF-1 circulating levels and hepatic mRNA expression. In this study, we found that perinatal administration of IPLEX, even if does not influence survival and body weight of mice, results in reduced degeneration of MNs, increased muscle fiber size and in amelioration of motor functions in SMA mice. Additionally, we show that phenotypic changes observed are not SMN-dependent, since no significant SMN modification was addressed in treated mice. Collectively, our data indicate IPLEX as a good therapeutic candidate to hinder the progression of the neurodegenerative process in SMA.
Collapse
Affiliation(s)
- Michela Murdocca
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
Spinal muscular atrophy is an autosomal recessive disorder characterised by degeneration of motor neurons in the spinal cord and is caused by mutations of the survival of motor neuron 1 gene SMN1. The severity of spinal muscular atrophy is highly variable and no cure is available at present. Consensus has been reached on several aspects of care, the availability of which can have a substantial effect on prognosis, but controversies remain. The development of standards of care for children with the disorder and the identification of promising treatment strategies have changed the natural history of spinal muscular atrophy, and the prospects are good for further improvements in function, quality of life, and survival. A long-term benefit for patients will be the development of effective interventions (such as antisense oligonucleotides), some of which are in clinical trials. The need to be prepared for clinical trials has been the impetus for a remarkable and unprecedented cooperation between clinicians, scientists, industry, government, and volunteer organisations on an international scale.
Collapse
|
24
|
Abstract
PURPOSE OF REVIEW The heterogeneous nature of neuromuscular disorders (NMDs) continues to promote slow but steady advances in diagnosis, classification, and treatment. This review focuses on the updates in the general management and treatment of NMDs, with emphasis on key updates in muscular dystrophy, myotonic dystrophy, mitochondrial myopathy, spinal muscular atrophy, and hereditary neuropathies. RECENT FINDINGS Current research shows that improvements in morbidity and mortality in various NMDs may be possible. Key components include advances in identification and classification of individual NMDs; attention to anesthetic and surgical risks; aggressive pulmonary care; and implementations of a proactive, multidisciplinary, standard-of-care approach. Innovative molecular and pharmaceutical therapeutic options are being investigated in many of these disorders, but unfortunately no new intervention has borne out. SUMMARY Important advances were made in the last year in the field of neuromuscular disease. However, because of their heterogeneous nature and rarity, diagnosis and treatment of these disorders either as a single disorder or as a group continue to be both a clinical and a research challenge. It is of utmost importance that clinicians and researchers be aware of these disorders to aid in identification and treatment.
Collapse
|
25
|
Dobrowolski SF, Pham HT, Downes FP, Prior TW, Naylor EW, Swoboda KJ. Newborn screening for spinal muscular atrophy by calibrated short-amplicon melt profiling. Clin Chem 2012; 58:1033-9. [PMID: 22490618 DOI: 10.1373/clinchem.2012.183038] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND The management options for the autosomal recessive neurodegenerative disorder spinal muscular atrophy (SMA) are evolving; however, their efficacy may require presymptom diagnosis and continuous treatment. To identify presymptomatic SMA patients, we created a DNA-based newborn screening assay to identify the homozygous deletions of the SMN1 (survival of motor neuron 1, telomeric) gene observed in 95%-98% of affected patients. METHODS We developed primers that amplify a 52-bp PCR product from homologous regions in the SMN1 and SMN2 (survival of motor neuron 2, centromeric) genes that flank a divergent site at site c.840. Post-PCR high-resolution melt profiling assessed the amplification product, and we used a unique means of melt calibration to normalize profiles. Samples that we had previously characterized for the numbers of SMN1 and SMN2 copies established genotypes associated with particular profiles. The system was evaluated with approximately 1000 purified DNA samples, 100 self-created dried blood spots, and >1200 dried blood spots from newborn screening tests. RESULTS Homozygous deletion of SMN1 exon 7 produced a distinctive melt profile that identified SMA patients. Samples with different numbers of SMN1 and SMN2 copies were resolved by their profiles. All samples with homozygous deletions were unambiguously recognized, and no normal sample was misidentified as a positive. CONCLUSIONS This assay has characteristics suitable for population-based screening. A reliable screening test will facilitate the identification of an SMA-affected cohort to receive early intervention to maximize the benefit from treatment. A prospective screening trial will allow the efficacy of treatment options to be assessed, which may justify the inclusion of SMA as a target for population screening.
Collapse
Affiliation(s)
- Steven F Dobrowolski
- Department of Pathology, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
| | | | | | | | | | | |
Collapse
|
26
|
Affiliation(s)
- Balraj Mittal
- Department of Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow 226 014, India.
| |
Collapse
|