1
|
Akabane T, Sagae H, van Wijk K, Saitoh S, Kimura T, Okano S, Kodama K, Takahashi K, Nakajima M, Tanaka T, Takagi M, Nakajima O. Heme deficiency in skeletal muscle exacerbates sarcopenia and impairs autophagy by reducing AMPK signaling. Sci Rep 2024; 14:22147. [PMID: 39333763 PMCID: PMC11437137 DOI: 10.1038/s41598-024-73049-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 09/12/2024] [Indexed: 09/30/2024] Open
Abstract
Heme serves as a prosthetic group in hemoproteins, including subunits of the mammalian mitochondrial electron transfer chain. The first enzyme in vertebrate heme biosynthesis, 5-aminolevulinic acid synthase 1 (ALAS1), is ubiquitously expressed and essential for producing 5-aminolevulinic acid (ALA). We previously showed that Alas1 heterozygous mice at 20-35 weeks (aged-A1+/-s) manifested impaired glucose metabolism, mitochondrial malformation in skeletal muscle, and reduced exercise tolerance, potentially linked to autophagy dysfunction. In this study, we investigated autophagy in A1+/-s and a sarcopenic phenotype in A1+/-s at 75-95 weeks (senile-A1+/-s). Senile-A1+/-s exhibited significantly reduced body and gastrocnemius muscle weight, and muscle strength, indicating an accelerated sarcopenic phenotype. Decreases in total LC3 and LC3-II protein and Map1lc3a mRNA levels were observed in aged-A1+/-s under fasting conditions and in Alas1 knockdown myocyte-differentiated C2C12 cells (A1KD-C2C12s) cultured in high- or low-glucose medium. ALA treatment largely reversed these declines. Reduced AMP-activated protein kinase (AMPK) signaling was associated with decreased autophagy in aged-A1+/-s and A1KD-C2C12s. AMPK modulation using AICAR (activator) and dorsomorphin (inhibitor) affected LC3 protein levels in an AMPK-dependent manner. Our findings suggest that heme deficiency contributes to accelerated sarcopenia-like defects and reduced autophagy in skeletal muscle, primarily due to decreased AMPK signaling.
Collapse
Affiliation(s)
- Takeru Akabane
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
- Department of Orthopaedic Surgery, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Hiromori Sagae
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
- Department of Orthopaedic Surgery, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Koen van Wijk
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
| | - Shinichi Saitoh
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
| | - Tomohiro Kimura
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
| | - Satoshi Okano
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan
| | | | | | | | | | - Michiaki Takagi
- Department of Orthopaedic Surgery, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Osamu Nakajima
- Department of Functional Genomics, Major of Innovative Medical Science Research, Yamagata University School of Medicine/Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Iida-Nishi 2-2-2 Yamagata, Yamagata, 990-9585, Japan.
| |
Collapse
|
2
|
Haque US, Yokota T. Recent Progress in Gene-Targeting Therapies for Spinal Muscular Atrophy: Promises and Challenges. Genes (Basel) 2024; 15:999. [PMID: 39202360 PMCID: PMC11353366 DOI: 10.3390/genes15080999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 07/20/2024] [Accepted: 07/22/2024] [Indexed: 09/03/2024] Open
Abstract
Spinal muscular atrophy (SMA) is a severe genetic disorder characterized by the loss of motor neurons, leading to progressive muscle weakness, loss of mobility, and respiratory complications. In its most severe forms, SMA can result in death within the first two years of life if untreated. The condition arises from mutations in the SMN1 (survival of motor neuron 1) gene, causing a deficiency in the survival motor neuron (SMN) protein. Humans possess a near-identical gene, SMN2, which modifies disease severity and is a primary target for therapies. Recent therapeutic advancements include antisense oligonucleotides (ASOs), small molecules targeting SMN2, and virus-mediated gene replacement therapy delivering a functional copy of SMN1. Additionally, recognizing SMA's broader phenotype involving multiple organs has led to the development of SMN-independent therapies. Evidence now indicates that SMA affects multiple organ systems, suggesting the need for SMN-independent treatments along with SMN-targeting therapies. No single therapy can cure SMA; thus, combination therapies may be essential for comprehensive treatment. This review addresses the SMA etiology, the role of SMN, and provides an overview of the rapidly evolving therapeutic landscape, highlighting current achievements and future directions.
Collapse
Affiliation(s)
- Umme Sabrina Haque
- Department of Neuroscience, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Toshifumi Yokota
- Department of Neuroscience, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada;
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
- The Friends of Garrett Cumming Research & Muscular Dystrophy Canada HM Toupin Neurological Science Research, Edmonton, AB T6G 2H7, Canada
| |
Collapse
|
3
|
Lan XQ, Deng CJ, Wang QQ, Zhao LM, Jiao BW, Xiang Y. The role of TGF-β signaling in muscle atrophy, sarcopenia and cancer cachexia. Gen Comp Endocrinol 2024; 353:114513. [PMID: 38604437 DOI: 10.1016/j.ygcen.2024.114513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/24/2024] [Accepted: 04/03/2024] [Indexed: 04/13/2024]
Abstract
Skeletal muscle, comprising a significant proportion (40 to 50 percent) of total body weight in humans, plays a critical role in maintaining normal physiological conditions. Muscle atrophy occurs when the rate of protein degradation exceeds protein synthesis. Sarcopenia refers to age-related muscle atrophy, while cachexia represents a more complex form of muscle wasting associated with various diseases such as cancer, heart failure, and AIDS. Recent research has highlighted the involvement of signaling pathways, including IGF1-Akt-mTOR, MuRF1-MAFbx, and FOXO, in regulating the delicate balance between muscle protein synthesis and breakdown. Myostatin, a member of the TGF-β superfamily, negatively regulates muscle growth and promotes muscle atrophy by activating Smad2 and Smad3. It also interacts with other signaling pathways in cachexia and sarcopenia. Inhibition of myostatin has emerged as a promising therapeutic approach for sarcopenia and cachexia. Additionally, other TGF-β family members, such as TGF-β1, activin A, and GDF11, have been implicated in the regulation of skeletal muscle mass. Furthermore, myostatin cooperates with these family members to impair muscle differentiation and contribute to muscle loss. This review provides an overview of the significance of myostatin and other TGF-β signaling pathway members in muscular dystrophy, sarcopenia, and cachexia. It also discusses potential novel therapeutic strategies targeting myostatin and TGF-β signaling for the treatment of muscle atrophy.
Collapse
Affiliation(s)
- Xin-Qiang Lan
- Metabolic Control and Aging Group, Human Aging Research Institute (HARI) and School of Life Science, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Cheng-Jie Deng
- Department of Biochemistry and Molecular Biology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, Yunnan, China
| | - Qi-Quan Wang
- Metabolic Control and Aging Group, Human Aging Research Institute (HARI) and School of Life Science, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Li-Min Zhao
- Senescence and Cancer Group, Human Aging Research Institute (HARI) and School of Life Science, Nanchang University, Nanchang 330031, Jiangxi, China
| | - Bao-Wei Jiao
- National Key Laboratory of Genetic Evolution & Animal Models, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Yang Xiang
- Metabolic Control and Aging Group, Human Aging Research Institute (HARI) and School of Life Science, Nanchang University, Nanchang 330031, Jiangxi, China.
| |
Collapse
|
4
|
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
|
5
|
Crawford TO, Darras BT, Day JW, Dunaway Young S, Duong T, Nelson LL, Barrett D, Song G, Bilic S, Cote S, Sadanowicz M, Iarrobino R, Xu TJ, O'Neil J, Rossello J, Place A, Kertesz N, Nomikos G, Chyung Y. Safety and Efficacy of Apitegromab in Patients With Spinal Muscular Atrophy Types 2 and 3: The Phase 2 TOPAZ Study. Neurology 2024; 102:e209151. [PMID: 38330285 PMCID: PMC11067700 DOI: 10.1212/wnl.0000000000209151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/20/2023] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND AND OBJECTIVES Currently approved therapies for spinal muscular atrophy (SMA) reverse the degenerative course, leading to better functional outcome, but they do not address the impairment arising from preexisting neurodegeneration. Apitegromab, an investigational, fully human monoclonal antibody, inhibits activation of myostatin (a negative regulator of skeletal muscle growth), thereby preserving muscle mass. The phase 2 TOPAZ trial assessed the safety and efficacy of apitegromab in individuals with later-onset type 2 and type 3 SMA. METHODS In this study, designed to investigate potential meaningful combinations of eligibility and treatment regimen for future studies, participants aged 2-21 years received IV apitegromab infusions every 4 weeks for 12 months in 1 of 3 cohorts. Cohort 1 stratified ambulatory participants aged 5-21 years into 2 arms (apitegromab 20 mg/kg alone or in combination with nusinersen); cohort 2 evaluated apitegromab 20 mg/kg combined with nusinersen in nonambulatory participants aged 5-21 years; and cohort 3 blindly evaluated 2 randomized apitegromab doses (2 and 20 mg/kg) combined with nusinersen in younger participants ≥2 years of age. The primary efficacy measure was mean change from baseline using the Hammersmith Functional Motor Scale version appropriate for each cohort. Data were analyzed using a paired t test with 2-sided 5% type 1 error for the mean change from baseline for predefined cohort-specific primary efficacy end points. RESULTS Fifty-eight participants (mean age 9.4 years) were enrolled at 16 trial sites in the United States and Europe. Participants had been treated with nusinersen for a mean of 25.9 months before enrollment in any of the 3 trial cohorts. At month 12, the mean change from baseline in Hammersmith scale score was -0.3 points (95% CI -2.1 to 1.4) in cohort 1 (n = 23), 0.6 points (-1.4 to 2.7) in cohort 2 (n = 15), and in cohort 3 (n = 20), the mean scores were 5.3 (-1.5 to 12.2) and 7.1 (1.8 to 12.5) for the 2-mg/kg (n = 8) and 20-mg/kg (n = 9) arms, respectively. The 5 most frequently reported treatment-emergent adverse events were headache (24.1%), pyrexia (22.4%), upper respiratory tract infection (22.4%), cough (22.4%), and nasopharyngitis (20.7%). No deaths or serious adverse reactions were reported. DISCUSSION Apitegromab led to improved motor function in participants with later-onset types 2 and 3 SMA. These results support a randomized, placebo-controlled phase 3 trial of apitegromab in participants with SMA. TRIAL REGISTRATION INFORMATION This trial is registered with ClinicalTrials.gov (NCT03921528). CLASSIFICATION OF EVIDENCE This study provides Class III evidence that apitegromab improves motor function in later-onset types 2 and 3 spinal muscular atrophy.
Collapse
Affiliation(s)
- Thomas O Crawford
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Basil T Darras
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - John W Day
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Sally Dunaway Young
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Tina Duong
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Leslie L Nelson
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Doreen Barrett
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Guochen Song
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Sanela Bilic
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Shaun Cote
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Mara Sadanowicz
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Ryan Iarrobino
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Tiina J Xu
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Janet O'Neil
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - José Rossello
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Amy Place
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Nathalie Kertesz
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - George Nomikos
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| | - Yung Chyung
- From the Department of Neurology (T.O.C.), Johns Hopkins University, Baltimore, MD; Department of Neurology (B.T.D.), Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (J.W.D., S.D.Y., T.D.), Stanford University, Palo Alto, CA; Department of Physical Therapy (L.L.N.), University of Texas Southwestern Medical Center, Dallas; Scholar Rock, Inc. (D.B., G.S., S.C., M.S., R.I., T.J.X., J.O.N., J.R., A.P., N.K., G.N., Y.C.), Cambridge, MA; Vanadro, LLC (S.B.), Urbandale, IA; Tourmaline Bio, Inc. (R.I.), New York, NY; Pfizer, Inc. (A.P.), New York, NY; Harmony Biosciences (G.N.), Plymouth Meeting, PA; and Stealth BioTherapeutics (Y.C.), Needham, MA
| |
Collapse
|
6
|
de Albuquerque ALA, Chadanowicz JK, Giudicelli GC, Staub ALP, Weber AC, Silva JMDS, Becker MM, Kowalski TW, Siebert M, Saute JAM. Serum myostatin as a candidate disease severity and progression biomarker of spinal muscular atrophy. Brain Commun 2024; 6:fcae062. [PMID: 38487549 PMCID: PMC10939446 DOI: 10.1093/braincomms/fcae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/18/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
The identification of biomarkers for spinal muscular atrophy is crucial for predicting disease progression, severity, and response to new disease-modifying therapies. This study aimed to investigate the role of serum levels of myostatin and follistatin as biomarkers for spinal muscular atrophy, considering muscle atrophy secondary to denervation as the main clinical manifestation of the disease. The study evaluated the differential gene expression of myostatin and follistatin in a lesional model of gastrocnemius denervation in mice, as well as in a meta-analysis of three datasets in transgenic mice models of spinal muscular atrophy, and in two studies involving humans with spinal muscular atrophy. Subsequently, a case-control study involving 27 spinal muscular atrophy patients and 27 controls was conducted, followed by a 12-month cohort study with 25 spinal muscular atrophy cases. Serum levels of myostatin and follistatin were analysed using enzyme-linked immunosorbent assay at a single centre in southern Brazil. Skeletal muscle gene expression of myostatin decreased and of follistatin increased following lesional muscle denervation in mice, consistent with findings in the spinal muscular atrophy transgenic mice meta-analysis and in the iliopsoas muscle of five patients with spinal muscular atrophy type 1. Median serum myostatin levels were significantly lower in spinal muscular atrophy patients (98 pg/mL; 5-157) compared to controls (412 pg/mL; 299-730) (P < 0.001). Lower myostatin levels were associated with greater disease severity based on clinician-rated outcomes (Rho = 0.493-0.812; P < 0.05). After 12 months, there was a further reduction in myostatin levels among spinal muscular atrophy cases (P = 0.021). Follistatin levels did not differ between cases and controls, and no significant changes were observed over time. The follistatin:myostatin ratio was significantly increased in spinal muscular atrophy subjects and inversely correlated with motor severity. Serum myostatin levels show promise as a novel biomarker for evaluating the severity and progression of spinal muscular atrophy. The decrease in myostatin levels and the subsequent favourable environment for muscle growth may be attributed to denervation caused by motor neuron dysfunction.
Collapse
Affiliation(s)
- Ana Letícia Amorim de Albuquerque
- Graduate Program in Medicine, Medical Sciences, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, Brazil
- Clinical Neurogenetics research group, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
| | - Júlia Kersting Chadanowicz
- Clinical Neurogenetics research group, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
| | - Giovanna Câmara Giudicelli
- Bioinformatics core, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
- Graduate Program in Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre 91501-970, Brazil
| | - Ana Lucia Portella Staub
- Clinical Neurogenetics research group, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
| | - Arthur Carpeggiani Weber
- Clinical Neurogenetics research group, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
| | | | | | - Thayne Woycinck Kowalski
- Bioinformatics core, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
- Graduate Program in Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre 91501-970, Brazil
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
| | - Marina Siebert
- Unit of Laboratorial Research, Experimental Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre 90035-007, Brazil
- Graduate Program in Gastroenterology and Hepatology, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, Brazil
| | - Jonas Alex Morales Saute
- Graduate Program in Medicine, Medical Sciences, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, Brazil
- Clinical Neurogenetics research group, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre 90035-007, Brazil
- Department of Internal Medicine, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, Brazil
| |
Collapse
|
7
|
Zheng Y, Yu Y, Feng J, Ling M, Wang X. Unveiling the Potential of Nelumbo nucifera-Derived Liensinine to Target The Myostatin Protein and to Counteract Muscle Atrophy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:2240-2249. [PMID: 38258624 DOI: 10.1021/acs.jafc.3c09002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Muscle atrophy refers to a decline in muscle mass and function, which has become a global concern due to the aging population. Various clinical trials have investigated the inhibitors of myostatin (MSTN). They have shown promising improvements in muscle function and quality of life. However, there are no drugs specifically targeting MSTN that have been approved for clinical use. In this study, we virtually screened liensinine (LIE), a food (Nelumbo nucifera)-derived compound, with low toxicity, from over 1.1 million compounds. We subsequently identified it as a potential candidate that targets MSTN by a cellular thermal shift assay (CETSA) and drug affinity response target stability (DARTS) assay. Further validation through cellular and in vivo studies demonstrated its promising potential in combating muscle atrophy. The mechanism of action may involve hindering the interaction between MSTN and the activin receptor type IIB (ActRIIB) and downregulating the expression of downstream proteins, including the muscle RING-finger protein-1 (MuRF-1) and muscle atrophy F-box (MAFbx)/Atrogin-1, ultimately promoting muscle regeneration. These results provide a strong foundation for future studies to explore the therapeutic potential of LIE in clinical settings.
Collapse
Affiliation(s)
- Youle Zheng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yixin Yu
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jin Feng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Min Ling
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| |
Collapse
|
8
|
Sharma R. Innovative Genoceuticals in Human Gene Therapy Solutions: Challenges and Safe Clinical Trials of Orphan Gene Therapy Products. Curr Gene Ther 2024; 24:46-72. [PMID: 37702177 DOI: 10.2174/1566523223666230911120922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/14/2023] [Accepted: 04/20/2023] [Indexed: 09/14/2023]
Abstract
The success of gene therapy attempts is controversial and inconclusive. Currently, it is popular among the public, the scientific community, and manufacturers of Gene Therapy Medical Products. In the absence of any remedy or treatment options available for untreatable inborn metabolic orphan or genetic diseases, cancer, or brain diseases, gene therapy treatment by genoceuticals and T-cells for gene editing and recovery remains the preferred choice as the last hope. A new concept of "Genoceutical Gene Therapy" by using orphan 'nucleic acid-based therapy' aims to introduce scientific principles of treating acquired tissue damage and rare diseases. These Orphan Genoceuticals provide new scope for the 'genodrug' development and evaluation of genoceuticals and gene products for ideal 'gene therapy' use in humans with marketing authorization application (MAA). This perspective study focuses on the quality control, safety, and efficacy requirements of using 'nucleic acid-based and human cell-based new gene therapy' genoceutical products to set scientific advice on genoceutical-based 'orphan genodrug' design for clinical trials as per Western and European guidelines. The ethical Western FDA and European EMA guidelines suggest stringent legal and technical requirements on genoceutical medical products or orphan genodrug use for other countries to frame their own guidelines. The introduction section proposes lessknown 'orphan drug-like' properties of modified RNA/DNA, human cell origin gene therapy medical products, and their transgene products. The clinical trial section explores the genoceutical sources, FDA/EMA approvals for genoceutical efficacy criteria with challenges, and ethical guidelines relating to gene therapy of specific rare metabolic, cancer and neurological diseases. The safety evaluation of approved genoceuticals or orphan drugs is highlighted with basic principles and 'genovigilance' requirements (to observe any adverse effects, side effects, developed signs/symptoms) to establish their therapeutic use. Current European Union and Food and Drug Administration guidelines continuously administer fast-track regulatory legal framework from time to time, and they monitor the success of gene therapy medical product efficacy and safety. Moreover, new ethical guidelines on 'orphan drug-like genoceuticals' are updated for biodistribution of the vector, genokinetics studies of the transgene product, requirements for efficacy studies in industries for market authorization, and clinical safety endpoints with their specific concerns in clinical trials or public use.
Collapse
Affiliation(s)
- Rakesh Sharma
- Surgery NMR Lab, Plastic Surgery Research, Massachusetts General Hospital, Boston, MA 02114, USA
- CCSU, Government Medical College, Saharanpur, 247232 India
| |
Collapse
|
9
|
Giorgia Q, Gomez Garcia de la Banda M, Smeriglio P. Role of circulating biomarkers in spinal muscular atrophy: insights from a new treatment era. Front Neurol 2023; 14:1226969. [PMID: 38020652 PMCID: PMC10679720 DOI: 10.3389/fneur.2023.1226969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a lower motor neuron disease due to biallelic mutations in the SMN1 gene on chromosome 5. It is characterized by progressive muscle weakness of limbs, bulbar and respiratory muscles. The disease is usually classified in four different phenotypes (1-4) according to age at symptoms onset and maximal motor milestones achieved. Recently, three disease modifying treatments have received approval from the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), while several other innovative drugs are under study. New therapies have been game changing, improving survival and life quality for SMA patients. However, they have also intensified the need for accurate biomarkers to monitor disease progression and treatment efficacy. While clinical and neurophysiological biomarkers are well established and helpful in describing disease progression, there is a great need to develop more robust and sensitive circulating biomarkers, such as proteins, nucleic acids, and other small molecules. Used alone or in combination with clinical biomarkers, they will play a critical role in enhancing patients' stratification for clinical trials and access to approved treatments, as well as in tracking response to therapy, paving the way to the development of individualized therapeutic approaches. In this comprehensive review, we describe the foremost circulating biomarkers of current significance, analyzing existing literature on non-treated and treated patients with a special focus on neurofilaments and circulating miRNA, aiming to identify and examine their role in the follow-up of patients treated with innovative treatments, including gene therapy.
Collapse
Affiliation(s)
- Querin Giorgia
- APHP, Service de Neuromyologie, Hôpital Pitié-Salpêtrière, Centre Référent pour les Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
- Institut de Myologie, I-Motion Clinical Trials Platform, Paris, France
- European Reference Center Network (Euro-NMD ERN), Paris, France
| | - Marta Gomez Garcia de la Banda
- Institut de Myologie, I-Motion Clinical Trials Platform, Paris, France
- APHP, Pediatric Neurology Department, Hôpital Armand Trousseau, Centre Référent pour les Maladies Neuromusculaires Nord/Est/Ile de France, Paris, France
- APHP, Pediatric Neurology and ICU Department, Université Paris Saclay, DMU Santé de l'Enfant et de l'Adolescent, Hôpital Raymond Poincaré, Garches, France
| | - Piera Smeriglio
- Centre of Research in Myology, Institute of Myology, Sorbonne Université, INSERM, Paris, France
| |
Collapse
|
10
|
Pomp L, Jeneson JAL, van der Pol WL, Bartels B. Electrophysiological and Imaging Biomarkers to Evaluate Exercise Training in Patients with Neuromuscular Disease: A Systematic Review. J Clin Med 2023; 12:6834. [PMID: 37959299 PMCID: PMC10647337 DOI: 10.3390/jcm12216834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023] Open
Abstract
Exercise therapy as part of the clinical management of patients with neuromuscular diseases (NMDs) is complicated by the limited insights into its efficacy. There is an urgent need for sensitive and non-invasive quantitative muscle biomarkers to monitor the effects of exercise training. Therefore, the objective of this systematic review was to critically appraise and summarize the current evidence for the sensitivity of quantitative, non-invasive biomarkers, based on imaging and electrophysiological techniques, for measuring the effects of physical exercise training. We identified a wide variety of biomarkers, including imaging techniques, i.e., magnetic resonance imaging (MRI) and ultrasound, surface electromyography (sEMG), magnetic resonance spectroscopy (MRS), and near-infrared spectroscopy (NIRS). Imaging biomarkers, such as muscle maximum area and muscle thickness, and EMG biomarkers, such as compound muscle action potential (CMAP) amplitude, detected significant changes in muscle morphology and neural adaptations following resistance training. MRS and NIRS biomarkers, such as initial phosphocreatine recovery rate (V), mitochondrial capacity (Qmax), adenosine phosphate recovery half-time (ADP t1/2), and micromolar changes in deoxygenated hemoglobin and myoglobin concentrations (Δ[deoxy(Hb + Mb)]), detected significant adaptations in oxidative metabolism after endurance training. We also identified biomarkers whose clinical relevance has not yet been assessed due to lack of sufficient study.
Collapse
Affiliation(s)
- Lisa Pomp
- Child Development and Exercise Center, Wilhelmina Children’s Hospital, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Jeroen Antonius Lodewijk Jeneson
- Child Development and Exercise Center, Wilhelmina Children’s Hospital, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - W. Ludo van der Pol
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Bart Bartels
- Child Development and Exercise Center, Wilhelmina Children’s Hospital, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| |
Collapse
|
11
|
Jha NN, Kim JK, Her YR, Monani UR. Muscle: an independent contributor to the neuromuscular spinal muscular atrophy disease phenotype. JCI Insight 2023; 8:e171878. [PMID: 37737261 PMCID: PMC10561723 DOI: 10.1172/jci.insight.171878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a pediatric-onset neuromuscular disorder caused by insufficient survival motor neuron (SMN) protein. SMN restorative therapies are now approved for the treatment of SMA; however, they are not curative, likely due to a combination of imperfect treatment timing, inadequate SMN augmentation, and failure to optimally target relevant organs. Here, we consider the implications of imperfect treatment administration, focusing specifically on outcomes for skeletal muscle. We examine the evidence that muscle plays a contributing role in driving neuromuscular dysfunction in SMA. Next, we discuss how SMN might regulate the health of myofibers and their progenitors. Finally, we speculate on therapeutic outcomes of failing to raise muscle SMN to healthful levels and present strategies to restore function to this tissue to ensure better treatment results.
Collapse
Affiliation(s)
- Narendra N. Jha
- Department of Neurology
- Center for Motor Neuron Biology and Disease, and
| | - Jeong-Ki Kim
- Department of Neurology
- Center for Motor Neuron Biology and Disease, and
| | - Yoon-Ra Her
- Department of Neurology
- Center for Motor Neuron Biology and Disease, and
| | - Umrao R. Monani
- Department of Neurology
- Center for Motor Neuron Biology and Disease, and
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| |
Collapse
|
12
|
Balaji L, Farrar MA, D'Silva AM, Kariyawasam DS. Decision-making and challenges within the evolving treatment algorithm in spinal muscular atrophy: a clinical perspective. Expert Rev Neurother 2023; 23:571-586. [PMID: 37227306 DOI: 10.1080/14737175.2023.2218549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/23/2023] [Indexed: 05/26/2023]
Abstract
INTRODUCTION The clinical application of disease modifying therapies has dramatically changed the paradigm of the management of people with spinal muscular atrophy (SMA), from sole reliance on symptomatic care directed toward the downstream consequences of muscle weakness, to proactive intervention and even preventative care. AREAS COVERED In this perspective, the authors evaluate the contemporary therapeutic landscape of SMA and discuss the evolution of novel phenotypes and the treatment algorithm, including the key factors that define individual treatment choice and treatment response. The benefits achieved by early diagnosis and treatment through newborn screening are highlighted, alongside an appraisal of emerging prognostic methods and classification frameworks to inform clinicians, patients, and families about disease course, manage expectations, and improve care planning. A future perspective of unmet needs and challenges is provided, emphasizing the key role of research. EXPERT OPINION SMN-augmenting therapies have improved health outcomes for people with SMA and powered the practice of personalized medicine. Within this new proactive diagnostic and treatment paradigm, new phenotypes and different disease trajectories are emerging. Ongoing collaborative research efforts to understand the biology of SMA and define optimal response are critical to refining future approaches.
Collapse
Affiliation(s)
- Lakshmi Balaji
- Department of Neurology, Sydney Children's Hospital Network, Sydney, New South Wales, Australia
- Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health UNSW, Sydney, Australia
| | - Michelle A Farrar
- Department of Neurology, Sydney Children's Hospital Network, Sydney, New South Wales, Australia
- Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health UNSW, Sydney, Australia
- UNSW Kensington Campus, Sydney, Australia
| | - Arlene M D'Silva
- Department of Neurology, Sydney Children's Hospital Network, Sydney, New South Wales, Australia
- Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health UNSW, Sydney, Australia
- UNSW Kensington Campus, Sydney, Australia
| | - Didu S Kariyawasam
- Department of Neurology, Sydney Children's Hospital Network, Sydney, New South Wales, Australia
- Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health UNSW, Sydney, Australia
| |
Collapse
|
13
|
Sun J, Harrington MA, Porter B. Sex Difference in Spinal Muscular Atrophy Patients - are Males More Vulnerable? J Neuromuscul Dis 2023; 10:847-867. [PMID: 37393514 PMCID: PMC10578261 DOI: 10.3233/jnd-230011] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2023] [Indexed: 07/03/2023]
Abstract
BACKGROUND Sex is a significant risk factor in many neurodegenerative disorders. A better understanding of the molecular mechanisms behind sex differences could help develop more targeted therapies that would lead to better outcomes. Untreated spinal muscular atrophy (SMA) is the leading genetic motor disorder causing infant mortality. SMA has a broad spectrum of severity ranging from prenatal death to infant mortality to normal lifespan with some disability. Scattered evidence points to a sex-specific vulnerability in SMA. However, the role of sex as a risk factor in SMA pathology and treatment has received limited attention. OBJECTIVE Systematically investigate sex differences in the incidence, symptom severity, motor function of patients with different types of SMA, and in the development of SMA1 patients. METHODS Aggregated data of SMA patients were obtained from the TREAT-NMD Global SMA Registry and the Cure SMA membership database by data enquiries. Data were analyzed and compared with publicly available standard data and data from published literature. RESULTS The analysis of the aggregated results from the TREAT-NMD dataset revealed that the male/female ratio was correlated to the incidence and prevalence of SMA from different countries; and for SMA patients, more of their male family members were affected by SMA. However, there was no significant difference of sex ratio in the Cure SMA membership dataset. As quantified by the clinician severity scores, symptoms were more severe in males than females in SMA types 2 and 3b. Motor function scores measured higher in females than males in SMA types 1, 3a and 3b. The head circumference was more strongly affected in male SMA type 1 patients. CONCLUSIONS The data in certain registry datasets suggest that males may be more vulnerable to SMA than females. The variability observed indicates that more investigation is necessary to fully understand the role of sex differences in SMA epidemiology, and to guide development of more targeted treatments.
Collapse
Affiliation(s)
- Jianli Sun
- Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, USA
- Department of Biological Sciences, Delaware State University, Dover, DE, USA
| | - Melissa A. Harrington
- Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, USA
| | - Ben Porter
- TREAT-NMD Services Limited, Newcastle upon Tyne, UK
| | - on behalf of the TREAT-NMD Global Registry Network for SMA
- Delaware Center for Neuroscience Research, Delaware State University, Dover, DE, USA
- Department of Biological Sciences, Delaware State University, Dover, DE, USA
- TREAT-NMD Services Limited, Newcastle upon Tyne, UK
| |
Collapse
|
14
|
Willoughby DS, Cardaci TD, Machek SB, Wilburn DT, Heileson JL. Resistance Exercise-Induced Increases in Muscle Myostatin mRNA and Protein Expression Are Subsequently Decreased in Circulation in the Presence of Increased Levels of the Extracellular Matrix Stabilizing Protein Decorin. J Sports Sci Med 2022; 21:616-624. [PMID: 36523894 PMCID: PMC9741719 DOI: 10.52082/jssm.2022.616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022]
Abstract
Resistance exercise (RE) activates cell signaling pathways associated with myostatin. Decorin is located in the extracellular matrix (ECM) and can block the inhibitory effect of myostatin. This study sought to determine the impact of low-load (LL) and high-load (HL) RE on myostatin mRNA and protein expression along with changes in muscle decorin and circulating follistatin. Ten resistance-trained men performed a LL (50% 1RM) and HL (80% 1RM) RE session using the angled leg press and leg extension with load and volume equated. Venous blood samples and muscle biopsies were obtained prior to and at 3h and 24h following each RE session. Muscle myostatin mRNA expression was increased at 24h post-exercise (p = 0.032) in LL and at 3h (p = 0.044) and 24h (p = 0.003) post-exercise in HL. Muscle decorin was increased at 24h post-exercise (p < 0.001) in LL and HL; however, muscle myostatin was increased at 24h post-exercise (p < 0.001) only in HL. For muscle Smad 2/3, no significant differences were observed (p > 0.05). Serum follistatin was increased and myostatin decreased at 24h post-exercise (p < 0.001) in LL and HL. Muscle myostatin gene and protein expression increased in response to HL RE. However, serum myostatin was decreased in the presence of increases in decorin in muscle and follistatin in circulation. Therefore, our data suggest a possible mechanism may exist where decorin within the ECM is able to bind to, and decrease, myostatin that might otherwise enter the circulation for activin IIB (ACTIIB) receptor binding and subsequent canonical signaling through Smad 2/3.
Collapse
Affiliation(s)
- Darryn S. Willoughby
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA, Department of Health and Human Performance, Baylor University, Waco, TX, USA, School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
| | - Thomas D. Cardaci
- Department of Pathology, Microbiology, and Immunology, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Steven B. Machek
- Department of Kinesiology, California State University Monterey Bay, Seaside, CA, USA
| | - Dylan T. Wilburn
- Department of Health and Human Performance, Baylor University, Waco, TX, USA
| | - Jeffery L. Heileson
- Nutrition Services Division, Walter Reed National Military Medical Center, Bethesda, MD, USA
| |
Collapse
|
15
|
Fröhlich A, Diek M, von Haehling S, Anker MS. Furnishing the cachexia landscape: A year of research in JCSM. J Cachexia Sarcopenia Muscle 2022; 13:2763-2771. [PMID: 36510825 PMCID: PMC9745474 DOI: 10.1002/jcsm.13151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Ann‐Kathrin Fröhlich
- Berlin Institute of Health Center for Regenerative Therapies (BCRT)BerlinGermany
- German Centre for Cardiovascular Research (DZHK), partner site BerlinBerlinGermany
- Division of Cardiology and Metabolism, Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Virchow KlinikumBerlinGermany
| | - Monika Diek
- Division of Cardiology and Metabolism, Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Virchow KlinikumBerlinGermany
| | - Stephan von Haehling
- Department of Cardiology and PneumologyUniversity of Göttingen Medical CenterGöttingenGermany
- German Centre for Cardiovascular Research (DZHK), partner site GöttingenGöttingenGermany
| | - Markus S. Anker
- Berlin Institute of Health Center for Regenerative Therapies (BCRT)BerlinGermany
- German Centre for Cardiovascular Research (DZHK), partner site BerlinBerlinGermany
- Department of Cardiology (CBF)Charité—Universitätsmedizin BerlinBerlinGermany
| |
Collapse
|
16
|
Lin JZ, Ma JD, Yang LJ, Zou YW, Zhang XP, Pan J, Li QH, Li HG, Yang ZH, Wu T, Zhang Q, Mo YQ, Dai L. Myokine myostatin is a novel predictor of one-year radiographic progression in patients with rheumatoid arthritis: A prospective cohort study. Front Immunol 2022; 13:1005161. [PMID: 36330524 PMCID: PMC9623067 DOI: 10.3389/fimmu.2022.1005161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/05/2022] [Indexed: 11/23/2022] Open
Abstract
Background Associations between rheumatoid arthritis (RA) and reduced skeletal muscle have been studied, and we firstly reported myopenia independently predict one-year radiographic progression in RA. Myokine myostatin can negatively regulate skeletal muscle mass and promote osteoclast differentiation. However, there is no report about their relationships in RA patients. We firstly explored the relationship of serum myostatin and disease characteristics, as well as aggravated joint destruction during one-year follow-up. Methods Consecutive RA patients were recruited from a real-world prospective cohort and completed at least one-year follow-up. Baseline serum level of myostatin was measured by enzyme-linked immunosorbent assay. Clinical data in RA patients as well as muscle index in both RA patients and healthy controls were collected. One-year radiographic progression as primary outcome was defined by a change in the total Sharp/van der Heijde modified score ≥0.5 units. Results Totally 344 RA patients (age 47.9 ± 12.5 years, 84.0% female) and 118 healthy control subjects (age 42.8 ± 11.3 years, 74.6% female) were recruited. Compared with healthy controls, RA patients showed a higher level of serum myostatin at baseline (3.241 ± 1.679 ng/ml vs. 1.717 ± 0.872 ng/ml, P<0.001), although lower appendicular skeletal muscle mass index (ASMI, 6.0 ± 0.9 kg/m2vs. 6.5 ± 1.0 kg/m2, P<0.001). In RA patients, those with high myostatin level showed a higher rate of radiographic progression than low myostatin group (45.3% vs. 18.6%, P<0.001). Furtherly, RA patients were stratified into four subgroups according to serum myostatin and myopenia. Compared with other three subgroups, RA patients with high myostatin overlapping myopenia had the highest rate of radiographic progression (67.2% vs. 10.3%-31.4%, P<0.001), as well as the lowest proportion of remission and the highest rate of physical dysfunction during one-year follow-up. After adjustment for confounding factors, high serum myostatin (AOR=3.451, 95%CI: 2.016-5.905) and myopenia (AOR=2.387, 95%CI: 1.416-4.022) at baseline were risk factors for one-year radiographic progression, especially for those with high myostatin overlapping myopenia (AOR=10.425, 95%CI: 3.959-27.450) as the highest-risk individuals among four subgroups. Significant synergistic interaction effect was observed between high myostatin and myopenia on one-year radiographic progression (AP=66.3%, 95%CI: 43.2%-89.3%). Conclusion Myostatin is a novel predictor of aggravated joint destruction in RA patients which has synergistic interaction with myopenia for predicting value.
Collapse
Affiliation(s)
- Jian-Zi Lin
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jian-Da Ma
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Li-Juan Yang
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yao-Wei Zou
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xue-Pei Zhang
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jie Pan
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qian-Hua Li
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hong-Gui Li
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Ze-Hong Yang
- Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Tao Wu
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qian Zhang
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Ying-Qian Mo
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
- Department of Rheumatology, Shenshan Medical Center, Memorial Hospital of Sun Yat-Sen University, Shanwei, China
- *Correspondence: Ying-Qian Mo, ; Lie Dai,
| | - Lie Dai
- Department of Rheumatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
- *Correspondence: Ying-Qian Mo, ; Lie Dai,
| |
Collapse
|
17
|
Abstract
PURPOSE OF REVIEW The development of new therapies has brought spinal muscular atrophy (SMA) into the spotlight. However, this was preceded by a long journey - from the first clinical description to the discovery of the genetic cause to molecular mechanisms of RNA and DNA technology. RECENT FINDINGS Since 2016, the antisense oligonucleotide nusinersen has been (FDA) approved for the treatment of SMA, followed by the gene replacement therapy onasemnogene abeparvovec-xioi in 2019 and the small-molecule risdiplam in 2020. These drugs, all targeting upregulation of the SMN protein not only showed remarkable effects in clinical trials but also in real-world settings. SMA has been implemented in newborn screening in many countries around the world. SMN-independent strategies targeting skeletal muscle, for example, may play another therapeutic approach in the future. SUMMARY This review aims to summarize the major clinical and basic science achievements in the field of SMA.
Collapse
Affiliation(s)
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Hannover, Germany
| |
Collapse
|
18
|
Fisher G, Mackels L, Markati T, Sarkozy A, Ochala J, Jungbluth H, Ramdas S, Servais L. Early clinical and pre-clinical therapy development in Nemaline myopathy. Expert Opin Ther Targets 2022; 26:853-867. [PMID: 36524401 DOI: 10.1080/14728222.2022.2157258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Nemaline myopathies (NM) represent a group of clinically and genetically heterogeneous congenital muscle disorders with the common denominator of nemaline rods on muscle biopsy. NEB and ACTA1 are the most common causative genes. Currently, available treatments are supportive. AREAS COVERED We explored experimental treatments for NM, identifying at least eleven mainly pre-clinical approaches utilizing murine and/or human muscle cells. These approaches target either i) the causative gene or associated genes implicated in the same pathway; ii) pathophysiologically relevant biochemical mechanisms such as calcium/myosin regulation of muscle contraction; iii) myogenesis; iv) other therapies that improve or optimize muscle function more generally; v) and/or combinations of the above. The scope and efficiency of these attempts is diverse, ranging from gene-specific effects to those widely applicable to all NM-associated genes. EXPERT OPINION The wide range of experimental therapies currently under consideration for NM is promising. Potential translation into clinical use requires consideration of additional factors such as the potential muscle type specificity as well as the possibility of gene expression remodeling. Challenges in clinical translation include the rarity and heterogeneity of genotypes, phenotypes, and disease trajectories, as well as the lack of longitudinal natural history data and validated outcomes and biomarkers.
Collapse
Affiliation(s)
- Gemma Fisher
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK
| | - Laurane Mackels
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Neuromuscular Reference Center, University and University Hospital of Liège, Liège, Belgium
| | - Theodora Markati
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK
| | - Anna Sarkozy
- Dubowitz Neuromuscular Centre, UCL Great Ormond Street Hospital, Institute of Child Health, London, UK
| | - Julien Ochala
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Heinz Jungbluth
- Department of Paediatric Neurology - Neuromuscular Service, Evelina Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London, UK.,Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
| | - Sithara Ramdas
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK
| | - Laurent Servais
- MDUK Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford, UK.,Neuromuscular Reference Center, University and University Hospital of Liège, Liège, Belgium
| |
Collapse
|
19
|
A New Method of Myostatin Inhibition in Mice via Oral Administration of Lactobacillus casei Expressing Modified Myostatin Protein, BLS-M22. Int J Mol Sci 2022; 23:ijms23169059. [PMID: 36012334 PMCID: PMC9409196 DOI: 10.3390/ijms23169059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/28/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022] Open
Abstract
Myostatin is a member of the transforming growth factor-beta superfamily and is an endogenous negative regulator of muscle growth. This study aimed to determine whether an oral administration of Lactobacillus casei expressing modified human myostatin (BLS-M22) could elicit sufficient levels of myostatin-specific antibody and improve the dystrophic features of an animal model of Duchenne muscular dystrophy (DMD; mdx mouse). BLS-M22 is a recombinant L. casei engineered to harbor the pKV vector and poly-gamma-glutamic acid gene linked to a modified human myostatin gene. Serological analysis showed that anti-myostatin IgG titers were significantly increased, and serum creatine kinase was significantly reduced in the BLS-M22-treated mdx mice compared to the control mice. In addition, treatment of BLS-M22 resulted in a significant increase in body weight and motor function (Rotarod behavior test). Histological analysis showed an improvement in the dystrophic features (fibrosis and muscle hypertrophy) of the mdx mice with the administration of BLS-M22. The circulating antibodies generated after BLS-M22 oral administration successfully lowered serum myostatin concentration. Myostatin blockade resulted in serological, histological, and functional improvements in mdx mice. Overall, the findings suggest the potential of BLS-M22 to treat DMD; however, further clinical trials are essential to ascertain its efficacy and safety in humans.
Collapse
|
20
|
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in SMN1 (encoding survival motor neuron protein (SMN)). Reduced expression of SMN leads to loss of α-motor neurons, severe muscle weakness and often early death. Standard-of-care recommendations for multidisciplinary supportive care of SMA were established in the past few decades. However, improved understanding of the pathogenetic mechanisms of SMA has led to the development of different therapeutic approaches. Three treatments that increase SMN expression by distinct molecular mechanisms, administration routes and tissue biodistributions have received regulatory approval with others in clinical development. The advent of the new therapies is redefining standards of care as in many countries most patients are treated with one of the new therapies, leading to the identification of emerging new phenotypes of SMA and a renewed characterization of demographics owing to improved patient survival.
Collapse
|
21
|
Abati E, Manini A, Comi GP, Corti S. Inhibition of myostatin and related signaling pathways for the treatment of muscle atrophy in motor neuron diseases. Cell Mol Life Sci 2022; 79:374. [PMID: 35727341 PMCID: PMC9213329 DOI: 10.1007/s00018-022-04408-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/16/2022] [Accepted: 06/01/2022] [Indexed: 11/26/2022]
Abstract
Myostatin is a negative regulator of skeletal muscle growth secreted by skeletal myocytes. In the past years, myostatin inhibition sparked interest among the scientific community for its potential to enhance muscle growth and to reduce, or even prevent, muscle atrophy. These characteristics make it a promising target for the treatment of muscle atrophy in motor neuron diseases, namely, amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), which are rare neurological diseases, whereby the degeneration of motor neurons leads to progressive muscle loss and paralysis. These diseases carry a huge burden of morbidity and mortality but, despite this unfavorable scenario, several therapeutic advancements have been made in the past years. Indeed, a number of different curative therapies for SMA have been approved, leading to a revolution in the life expectancy and outcomes of SMA patients. Similarly, tofersen, an antisense oligonucleotide, is now undergoing clinical trial phase for use in ALS patients carrying the SOD1 mutation. However, these therapies are not able to completely halt or reverse progression of muscle damage. Recently, a trial evaluating apitegromab, a myostatin inhibitor, in SMA patients was started, following positive results from preclinical studies. In this context, myostatin inhibition could represent a useful strategy to tackle motor symptoms in these patients. The aim of this review is to describe the myostatin pathway and its role in motor neuron diseases, and to summarize and critically discuss preclinical and clinical studies of myostatin inhibitors in SMA and ALS. Then, we will highlight promises and pitfalls related to the use of myostatin inhibitors in the human setting, to aid the scientific community in the development of future clinical trials.
Collapse
Affiliation(s)
- Elena Abati
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Neurology Unit, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
- Neurology Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Arianna Manini
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Neurology Unit, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Giacomo Pietro Comi
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Neurology Unit, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
- Neurology Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Department of Pathophysiology and Transplantation (DEPT), Dino Ferrari Centre, Neuroscience Section, Neurology Unit, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, University of Milan, Milan, Italy.
- Neurology Unit, Department of Neuroscience, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
| |
Collapse
|
22
|
Leier A, Moore M, Liu H, Daniel M, Hyde AM, Messiaen L, Korf BR, Selvakumaran J, Ciszewski L, Lambert L, Foote J, Wallace MR, Kesterson RA, Dickson G, Popplewell L, Wallis D. Targeted exon skipping of NF1 exon 17 as a therapeutic for neurofibromatosis type I. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 28:261-278. [PMID: 35433111 PMCID: PMC8983316 DOI: 10.1016/j.omtn.2022.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/12/2022] [Indexed: 12/14/2022]
Abstract
We investigated the feasibility of utilizing an exon-skipping approach as a genotype-dependent therapeutic for neurofibromatosis type 1 (NF1) by determining which NF1 exons might be skipped while maintaining neurofibromin protein expression and GTPase activating protein (GAP)-related domain (GRD) function. Initial in silico analysis predicted exons that can be skipped with minimal loss of neurofibromin function, which was confirmed by in vitro assessments utilizing an Nf1 cDNA-based functional screening system. Skipping of exons 17 or 52 fit our criteria, as minimal effects on protein expression and GRD activity were noted. Antisense phosphorodiamidate morpholino oligomers (PMOs) were utilized to skip exon 17 in human cell lines with patient-specific pathogenic variants in exon 17, c.1885G>A, and c.1929delG. PMOs restored functional neurofibromin expression. To determine the in vivo significance of exon 17 skipping, we generated a homozygous deletion of exon 17 in a novel mouse model. Mice were viable and exhibited a normal lifespan. Initial studies did not reveal the presence of tumor development; however, altered nesting behavior and systemic lymphoid hyperplasia was noted in peripheral lymphoid organs. Alterations in T and B cell frequencies in the thymus and spleen were identified. Hence, exon skipping should be further investigated as a therapeutic approach for NF1 patients with pathogenic variants in exon 17, as homozygous deletion of exon 17 is consistent with at least partial function of neurofibromin.
Collapse
Affiliation(s)
- André Leier
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Marc Moore
- Centre of Biomedical Science, Department of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Hui Liu
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Michael Daniel
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Alexis M. Hyde
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ludwine Messiaen
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Bruce R. Korf
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jamuna Selvakumaran
- Centre of Biomedical Science, Department of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Lukasz Ciszewski
- Centre of Biomedical Science, Department of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Laura Lambert
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jeremy Foote
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Margaret R. Wallace
- Department of Molecular Genetics and Microbiology, and UF Health Cancer Center, University of Florida, Gainesville, FL 32611, USA
| | - Robert A. Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - George Dickson
- Centre of Biomedical Science, Department of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Linda Popplewell
- Centre of Biomedical Science, Department of Biological Sciences, Royal Holloway - University of London, Egham, Surrey TW20 0EX, UK
| | - Deeann Wallis
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| |
Collapse
|
23
|
López-Cortés A, Echeverría-Garcés G, Ramos-Medina MJ. Molecular Pathogenesis and New Therapeutic Dimensions for Spinal Muscular Atrophy. BIOLOGY 2022; 11:biology11060894. [PMID: 35741415 PMCID: PMC9219894 DOI: 10.3390/biology11060894] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022]
Abstract
The condition known as 5q spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease caused by a deficiency of the ubiquitous protein survival of motor neuron (SMN), which is encoded by the SMN1 and SMN2 genes. It is one of the most common pediatric recessive genetic diseases, and it represents the most common cause of hereditary infant mortality. After decades of intensive basic and clinical research efforts, and improvements in the standard of care, successful therapeutic milestones have been developed, delaying the progression of 5q SMA and increasing patient survival. At the same time, promising data from early-stage clinical trials have indicated that additional therapeutic options are likely to emerge in the near future. Here, we provide updated information on the molecular underpinnings of SMA; we also provide an overview of the rapidly evolving therapeutic landscape for SMA, including SMN-targeted therapies, SMN-independent therapies, and combinational therapies that are likely to be key for the development of treatments that are effective across a patient’s lifespan.
Collapse
Affiliation(s)
- Andrés López-Cortés
- Programa de Investigación en Salud Global, Facultad de Ciencias de la Salud, Universidad Internacional SEK, Quito 170302, Ecuador
- Facultad de Medicina, Universidad de Las Américas, Quito 170124, Ecuador
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
- Correspondence:
| | - Gabriela Echeverría-Garcés
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| | - María José Ramos-Medina
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| |
Collapse
|
24
|
Brakemeier S, Stolte B, Kleinschnitz C, Hagenacker T. Treatment of Adult Spinal Muscular Atrophy: Overview and Recent Developments. Curr Pharm Des 2022; 28:892-898. [PMID: 35352647 DOI: 10.2174/1381612828666220329115433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 02/03/2022] [Indexed: 11/22/2022]
Abstract
Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disease leading to progressive and in many cases severe muscle weakness and atrophy in the natural disease course. An increasing number of gene-based treatment options have become available in recent years. Growing knowledge about the underlying genetic mechanisms makes the disease well amenable to this. Over the past few years, many data on new treatments, their mechanisms of action and therapeutic outcomes have been published, reflecting the current dynamics in this field. With the approval of the antisense oligonucleotide nusinersen, the vector-based therapy with onasemnogene abeparvovec and the small molecule splicing modifier risdiplam, three gene therapeutic drugs are available for the treatment of SMA showing improvement in motor function. But in the pivotal studies several relevant parameters have not been addressed. There is a data gap for the treatment outcome of adult individuals with SMA as well as for several other relevant outcome parameters like bulbary or ventilatory function. With increasing treatment options, additional individual therapies have become necessary. Studies on combination therapies or switch of therapy, e.g. the sequential administration of onasemnogen abeparvovec and nusinersen, are necessary. An overview of current developments in the field of therapeutic options for adult SMA is presented. Important characteristics of each therapeutic option will be discussed so that the reader can comprehend underlying pathophysiological mechanisms as well as advantages and disadvantages of each therapy. The focus is on gene-based treatment options, but options beyond this are also addressed.
Collapse
Affiliation(s)
- Svenja Brakemeier
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Benjamin Stolte
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Tim Hagenacker
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany
| |
Collapse
|
25
|
Rodgers BD, Ward CW. Myostatin/Activin Receptor Ligands in Muscle and the Development Status of Attenuating Drugs. Endocr Rev 2022; 43:329-365. [PMID: 34520530 PMCID: PMC8905337 DOI: 10.1210/endrev/bnab030] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Indexed: 02/07/2023]
Abstract
Muscle wasting disease indications are among the most debilitating and often deadly noncommunicable disease states. As a comorbidity, muscle wasting is associated with different neuromuscular diseases and myopathies, cancer, heart failure, chronic pulmonary and renal diseases, peripheral neuropathies, inflammatory disorders, and, of course, musculoskeletal injuries. Current treatment strategies are relatively ineffective and can at best only limit the rate of muscle degeneration. This includes nutritional supplementation and appetite stimulants as well as immunosuppressants capable of exacerbating muscle loss. Arguably, the most promising treatments in development attempt to disrupt myostatin and activin receptor signaling because these circulating factors are potent inhibitors of muscle growth and regulators of muscle progenitor cell differentiation. Indeed, several studies demonstrated the clinical potential of "inhibiting the inhibitors," increasing muscle cell protein synthesis, decreasing degradation, enhancing mitochondrial biogenesis, and preserving muscle function. Such changes can prevent muscle wasting in various disease animal models yet many drugs targeting this pathway failed during clinical trials, some from serious treatment-related adverse events and off-target interactions. More often, however, failures resulted from the inability to improve muscle function despite preserving muscle mass. Drugs still in development include antibodies and gene therapeutics, all with different targets and thus, safety, efficacy, and proposed use profiles. Each is unique in design and, if successful, could revolutionize the treatment of both acute and chronic muscle wasting. They could also be used in combination with other developing therapeutics for related muscle pathologies or even metabolic diseases.
Collapse
Affiliation(s)
| | - Christopher W Ward
- Department of Orthopedics and Center for Biomedical Engineering and Technology (BioMET), University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
26
|
Jablonka S, Hennlein L, Sendtner M. Therapy development for spinal muscular atrophy: perspectives for muscular dystrophies and neurodegenerative disorders. Neurol Res Pract 2022; 4:2. [PMID: 34983696 PMCID: PMC8725368 DOI: 10.1186/s42466-021-00162-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Major efforts have been made in the last decade to develop and improve therapies for proximal spinal muscular atrophy (SMA). The introduction of Nusinersen/Spinraza™ as an antisense oligonucleotide therapy, Onasemnogene abeparvovec/Zolgensma™ as an AAV9-based gene therapy and Risdiplam/Evrysdi™ as a small molecule modifier of pre-mRNA splicing have set new standards for interference with neurodegeneration. MAIN BODY Therapies for SMA are designed to interfere with the cellular basis of the disease by modifying pre-mRNA splicing and enhancing expression of the Survival Motor Neuron (SMN) protein, which is only expressed at low levels in this disorder. The corresponding strategies also can be applied to other disease mechanisms caused by loss of function or toxic gain of function mutations. The development of therapies for SMA was based on the use of cell culture systems and mouse models, as well as innovative clinical trials that included readouts that had originally been introduced and optimized in preclinical studies. This is summarized in the first part of this review. The second part discusses current developments and perspectives for amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease, as well as the obstacles that need to be overcome to introduce RNA-based therapies and gene therapies for these disorders. CONCLUSION RNA-based therapies offer chances for therapy development of complex neurodegenerative disorders such as amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease. The experiences made with these new drugs for SMA, and also the experiences in AAV gene therapies could help to broaden the spectrum of current approaches to interfere with pathophysiological mechanisms in neurodegeneration.
Collapse
Affiliation(s)
- Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
| |
Collapse
|
27
|
Chilcott EM, Muiruri EW, Hirst TC, Yáñez-Muñoz RJ. Systematic review and meta-analysis determining the benefits of in vivo genetic therapy in spinal muscular atrophy rodent models. Gene Ther 2022; 29:498-512. [PMID: 34611322 PMCID: PMC9482879 DOI: 10.1038/s41434-021-00292-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/30/2021] [Accepted: 09/12/2021] [Indexed: 01/31/2023]
Abstract
Spinal muscular atrophy (SMA) is a severe childhood neuromuscular disease for which two genetic therapies, Nusinersen (Spinraza, an antisense oligonucleotide), and AVXS-101 (Zolgensma, an adeno-associated viral vector of serotype 9 AAV9), have recently been approved. We investigated the pre-clinical development of SMA genetic therapies in rodent models and whether this can predict clinical efficacy. We have performed a systematic review of relevant publications and extracted median survival and details of experimental design. A random effects meta-analysis was used to estimate and compare efficacy. We stratified by experimental design (type of genetic therapy, mouse model, route and time of administration) and sought any evidence of publication bias. 51 publications were identified containing 155 individual comparisons, comprising 2573 animals in total. Genetic therapies prolonged survival in SMA mouse models by 3.23-fold (95% CI 2.75-3.79) compared to controls. Study design characteristics accounted for significant heterogeneity between studies and greatly affected observed median survival ratios. Some evidence of publication bias was found. These data are consistent with the extended average lifespan of Spinraza- and Zolgensma-treated children in the clinic. Together, these results support that SMA has been particularly amenable to genetic therapy approaches and highlight SMA as a trailblazer for therapeutic development.
Collapse
Affiliation(s)
- Ellie M. Chilcott
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK ,Present Address: Institute for Women’s Health, UCL, 86-96 Chenies Mews, London, WC1E 6HX UK
| | - Evalyne W. Muiruri
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK
| | - Theodore C. Hirst
- grid.416232.00000 0004 0399 1866Department of Neurosurgery, Royal Victoria Hospital, Belfast, BT12 6BA UK
| | - Rafael J. Yáñez-Muñoz
- grid.4970.a0000 0001 2188 881XAGCTlab.org, Centre of Gene and Cell Therapy, Centre for Biomedical Sciences, Department of Biological Sciences, School of Life Sciences and Environment, Royal Holloway University of London, TW20 0EX London, UK
| |
Collapse
|
28
|
Fröhlich A, Diek M, Denecke C, von Haehling S, Hadzibegovic S, Anker MS. JCSM: growing together with cachexia and sarcopenia research. J Cachexia Sarcopenia Muscle 2021; 12:1359-1367. [PMID: 34969163 PMCID: PMC8718022 DOI: 10.1002/jcsm.12886] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Ann‐Kathrin Fröhlich
- Berlin Institute of Health Center for Regenerative Therapies (BCRT)BerlinGermany
- German Centre for Cardiovascular Research (DZHK), partner site BerlinBerlinGermany
- Division of Cardiology and Metabolism, Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Virchow KlinikumBerlinGermany
| | - Monika Diek
- Division of Cardiology and Metabolism, Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Virchow KlinikumBerlinGermany
| | - Corinna Denecke
- Division of Cardiology and Metabolism, Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Virchow KlinikumBerlinGermany
| | - Stephan von Haehling
- Department of Cardiology and PneumologyUniversity of Göttingen Medical CenterGöttingenGermany
- German Centre for Cardiovascular Research (DZHK), partner site GöttingenGöttingenGermany
| | - Sara Hadzibegovic
- Berlin Institute of Health Center for Regenerative Therapies (BCRT)BerlinGermany
- German Centre for Cardiovascular Research (DZHK), partner site BerlinBerlinGermany
- Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Benjamin Franklin (CBF)BerlinGermany
| | - Markus S. Anker
- Berlin Institute of Health Center for Regenerative Therapies (BCRT)BerlinGermany
- German Centre for Cardiovascular Research (DZHK), partner site BerlinBerlinGermany
- Department of CardiologyCharité—Universitätsmedizin Berlin, Campus Benjamin Franklin (CBF)BerlinGermany
| |
Collapse
|
29
|
Mercuri E. Spinal muscular atrophy: from rags to riches. Neuromuscul Disord 2021; 31:998-1003. [PMID: 34736637 DOI: 10.1016/j.nmd.2021.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 11/30/2022]
Abstract
The aim of this paper is to provide a short history of spinal muscular atrophy, from the first descriptions of the disease to the impact of the most recent therapeutical advances on the disease course. The paper provides an overview of how the field has progressed over the years after the availability of care recommendations and, more recently of the new therapies. The paper also highlights the new challenges related to the interpretation of the efficacy of the new therapies and how these are likely to affect several aspects such as the classification of spinal muscular atrophy. We will also discuss the need for further work to better define possible new phenotypes and new methods of assessments and how these should be reflected in the care recommendations. The results in presymptomatic patients will finally highlight the need for neonatal screening.
Collapse
Affiliation(s)
- Eugenio Mercuri
- Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome 00168, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
| |
Collapse
|
30
|
Kray KM, McGovern VL, Chugh D, Arnold WD, Burghes AHM. Dual SMN inducing therapies can rescue survival and motor unit function in symptomatic ∆7SMA mice. Neurobiol Dis 2021; 159:105488. [PMID: 34425216 PMCID: PMC8502210 DOI: 10.1016/j.nbd.2021.105488] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/06/2021] [Accepted: 08/16/2021] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by survival motor neuron (SMN) protein deficiency which results in motor neuron loss and muscle atrophy. SMA is caused by a mutation or deletion of the survival motor neuron 1 (SMN1) gene and retention of the nearly identical SMN2 gene. SMN2 contains a C to T change in exon 7 that results in exon 7 exclusion from 90% of transcripts. SMN protein lacking exon 7 is unstable and rapidly degraded. The remaining full-length transcripts from SMN2 are insufficient for normal motor neuron function leading to the development of SMA. Three different therapeutic approaches that increase full-length SMN (FL-SMN) protein production are approved for treatment of SMA patients. Studies in both animal models and humans have demonstrated increasing SMN levels prior to onset of symptoms provides the greatest therapeutic benefit. Treatment of SMA, after some motor neuron loss has occurred, is also effective but to a lesser degree. The SMN∆7 mouse model is a well characterized model of severe or type 1 SMA, dying at 14 days of age. Here we treated three groups of ∆7SMA mice starting before, roughly during, and after symptom onset to determine if combining two mechanistically distinct SMN inducing therapies could improve the therapeutic outcome both before and after motor neuron loss. We found, compared with individual therapies, that morpholino antisense oligonucleotide (ASO) directed against ISS-N1 combined with the small molecule compound RG7800 significantly increased FL-SMN transcript and protein production resulting in improved survival and weight of ∆7SMA mice. Moreover, when give late symptomatically, motor unit function was completely rescued with no loss in function at 100 days of age in the dual treatment group. We have therefore shown that this dual therapeutic approach successfully increases SMN protein and rescues motor function in symptomatic ∆7SMA mice.
Collapse
Affiliation(s)
- Kaitlyn M Kray
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA.
| | - Vicki L McGovern
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA.
| | - Deepti Chugh
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA
| | - W David Arnold
- Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA.
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA; Department of Neurology, Neuromuscular Division, The Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA.
| |
Collapse
|
31
|
Lejman J, Zieliński G, Gawda P, Lejman M. Alternative Splicing Role in New Therapies of Spinal Muscular Atrophy. Genes (Basel) 2021; 12:1346. [PMID: 34573328 PMCID: PMC8468182 DOI: 10.3390/genes12091346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
It has been estimated that 80% of the pre-mRNA undergoes alternative splicing, which exponentially increases the flow of biological information in cellular processes and can be an attractive therapeutic target. It is a crucial mechanism to increase genetic diversity. Disturbed alternative splicing is observed in many disorders, including neuromuscular diseases and carcinomas. Spinal Muscular Atrophy (SMA) is an autosomal recessive neurodegenerative disease. Homozygous deletion in 5q13 (the region coding for the motor neuron survival gene (SMN1)) is responsible for 95% of SMA cases. The nearly identical SMN2 gene does not compensate for SMN loss caused by SMN1 gene mutation due to different splicing of exon 7. A pathologically low level of survival motor neuron protein (SMN) causes degeneration of the anterior horn cells in the spinal cord with associated destruction of α-motor cells and manifested by muscle weakness and loss. Understanding the regulation of the SMN2 pre-mRNA splicing process has allowed for innovative treatment and the introduction of new medicines for SMA. After describing the concept of splicing modulation, this review will cover the progress achieved in this field, by highlighting the breakthrough accomplished recently for the treatment of SMA using the mechanism of alternative splicing.
Collapse
Affiliation(s)
- Jan Lejman
- Student Scientific Society, Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland;
| | - Grzegorz Zieliński
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Piotr Gawda
- Department of Sports Medicine, Medical University of Lublin, 20-093 Lublin, Poland; (G.Z.); (P.G.)
| | - Monika Lejman
- Laboratory of Genetic Diagnostics, Medical University of Lublin, 20-093 Lublin, Poland
| |
Collapse
|
32
|
Gromova A, La Spada AR. Harmony Lost: Cell-Cell Communication at the Neuromuscular Junction in Motor Neuron Disease. Trends Neurosci 2021; 43:709-724. [PMID: 32846148 DOI: 10.1016/j.tins.2020.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/05/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022]
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that is the point of connection between motor neurons and skeletal muscle. Although developmental studies have established the importance of cell-cell communication at the NMJ for the integrity and full functionality of this synapse, the contribution of this structure as a primary driver in motor neuron disease pathogenesis remains uncertain. Here, we consider the biology of the NMJ and review emerging lines of investigation that are highlighting the importance of cell-cell interaction at the NMJ in spinal muscular atrophy (SMA), X-linked spinal and bulbar muscular atrophy (SBMA), and amyotrophic lateral sclerosis (ALS). Ongoing research may reveal NMJ targets and pathways whose therapeutic modulation will help slow the progression of motor neuron disease, offering a novel treatment paradigm for ALS, SBMA, SMA, and related disorders.
Collapse
Affiliation(s)
- Anastasia Gromova
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA; Department of Pathology and Laboratory Medicine and Department of Neurology, University of California Irvine, Irvine, CA 92697, USA
| | - Albert R La Spada
- Department of Pathology and Laboratory Medicine and Department of Neurology, University of California Irvine, Irvine, CA 92697, USA; Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA.
| |
Collapse
|
33
|
McCormack NM, Villalón E, Viollet C, Soltis AR, Dalgard CL, Lorson CL, Burnett BG. Survival motor neuron deficiency slows myoblast fusion through reduced myomaker and myomixer expression. J Cachexia Sarcopenia Muscle 2021; 12:1098-1116. [PMID: 34115448 PMCID: PMC8350220 DOI: 10.1002/jcsm.12740] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 05/05/2021] [Accepted: 05/21/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Spinal muscular atrophy is an inherited neurodegenerative disease caused by insufficient levels of the survival motor neuron (SMN) protein. Recently approved treatments aimed at increasing SMN protein levels have dramatically improved patient survival and have altered the disease landscape. While restoring SMN levels slows motor neuron loss, many patients continue to have smaller muscles and do not achieve normal motor milestones. While timing of treatment is important, it remains unclear why SMN restoration is insufficient to fully restore muscle size and function. We and others have shown that SMN-deficient muscle precursor cells fail to efficiently fuse into myotubes. However, the role of SMN in myoblast fusion is not known. METHODS In this study, we show that SMN-deficient myoblasts readily fuse with wild-type myoblasts, demonstrating fusion competency. Conditioned media from wild type differentiating myoblasts do not rescue the fusion deficit of SMN-deficient cells, suggesting that compromised fusion may primarily be a result of altered membrane dynamics at the cell surface. Transcriptome profiling of skeletal muscle from SMN-deficient mice revealed altered expression of cell surface fusion molecules. Finally, using cell and mouse models, we investigate if myoblast fusion can be rescued in SMN-deficient myoblast and improve the muscle pathology in SMA mice. RESULTS We found reduced expression of the muscle fusion proteins myomaker (P = 0.0060) and myomixer (P = 0.0051) in the muscle of SMA mice. Suppressing SMN expression in C2C12 myoblast cells reduces expression of myomaker (35% reduction; P < 0.0001) and myomixer, also known as myomerger and minion, (30% reduction; P < 0.0001) and restoring SMN levels only partially restores myomaker and myomixer expression. Ectopic expression of myomixer improves myofibre number (55% increase; P = 0.0006) and motor function (35% decrease in righting time; P = 0.0089) in SMA model mice and enhances motor function (82% decrease in righting time; P < 0.0001) and extends survival (28% increase; P < 0.01) when administered in combination with an antisense oligonucleotide that increases SMN protein levels. CONCLUSIONS Here, we identified reduced expression of muscle fusion proteins as a key factor in the fusion deficits of SMN-deficient myoblasts. This discovery provides a novel target to improve SMA muscle pathology and motor function, which in combination with SMN increasing therapy could enhance clinical outcomes for SMA patients.
Collapse
Affiliation(s)
- Nikki M McCormack
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Eric Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Coralie Viollet
- Collaborative Health Initiative Research Program, Uniformed Services University of the Heath Sciences, Bethesda, MD, USA
| | - Anthony R Soltis
- Collaborative Health Initiative Research Program, Uniformed Services University of the Heath Sciences, Bethesda, MD, USA.,Henry M. Jackson Foundation, Bethesda, MD, USA
| | - Clifton L Dalgard
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA.,Collaborative Health Initiative Research Program, Uniformed Services University of the Heath Sciences, Bethesda, MD, USA.,The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Christian L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Barrington G Burnett
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, USA
| |
Collapse
|
34
|
Chaytow H, Faller KM, Huang YT, Gillingwater TH. Spinal muscular atrophy: From approved therapies to future therapeutic targets for personalized medicine. Cell Rep Med 2021; 2:100346. [PMID: 34337562 PMCID: PMC8324491 DOI: 10.1016/j.xcrm.2021.100346] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating childhood motor neuron disease that, in the most severe cases and when left untreated, leads to death within the first two years of life. Recent therapeutic advances have given hope to families and patients by compensating for the deficiency in survival motor neuron (SMN) protein via gene therapy or other genetic manipulation. However, it is now apparent that none of these therapies will cure SMA alone. In this review, we discuss the three currently licensed therapies for SMA, briefly highlighting their respective advantages and disadvantages, before considering alternative approaches to increasing SMN protein levels. We then explore recent preclinical research that is identifying and targeting dysregulated pathways secondary to, or independent of, SMN deficiency that may provide adjunctive opportunities for SMA. These additional therapies are likely to be key for the development of treatments that are effective across the lifespan of SMA patients.
Collapse
Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Kiterie M.E. Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
35
|
Khorkova O, Hsiao J, Wahlestedt C. Nucleic Acid-Based Therapeutics in Orphan Neurological Disorders: Recent Developments. Front Mol Biosci 2021; 8:643681. [PMID: 33996898 PMCID: PMC8115123 DOI: 10.3389/fmolb.2021.643681] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/17/2021] [Indexed: 12/18/2022] Open
Abstract
The possibility of rational design and the resulting faster and more cost-efficient development cycles of nucleic acid–based therapeutics (NBTs), such as antisense oligonucleotides, siRNAs, and gene therapy vectors, have fueled increased activity in developing therapies for orphan diseases. Despite the difficulty of delivering NBTs beyond the blood–brain barrier, neurological diseases are significantly represented among the first targets for NBTs. As orphan disease NBTs are now entering the clinical stage, substantial efforts are required to develop the scientific background and infrastructure for NBT design and mechanistic studies, genetic testing, understanding natural history of orphan disorders, data sharing, NBT manufacturing, and regulatory support. The outcomes of these efforts will also benefit patients with “common” diseases by improving diagnostics, developing the widely applicable NBT technology platforms, and promoting deeper understanding of biological mechanisms that underlie disease pathogenesis. Furthermore, with successes in genetic research, a growing proportion of “common” disease cases can now be attributed to mutations in particular genes, essentially extending the orphan disease field. Together, the developments occurring in orphan diseases are building the foundation for the future of personalized medicine. In this review, we will focus on recent achievements in developing therapies for orphan neurological disorders.
Collapse
Affiliation(s)
| | | | - Claes Wahlestedt
- Center for Therapeutic Innovation and Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL, United States
| |
Collapse
|
36
|
Servais L, Baranello G, Scoto M, Daron A, Oskoui M. Therapeutic interventions for spinal muscular atrophy: preclinical and early clinical development opportunities. Expert Opin Investig Drugs 2021; 30:519-527. [PMID: 33749510 DOI: 10.1080/13543784.2021.1904889] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative neuromuscular disease that presents primarily in children. Abnormalities in the SMN1 gene cause reduced levels of the survival motor neuron (SMN) protein, while a second gene, SMN2, produces low levels of functional SMN protein. Currently available drugs do not cure, so a significant unmet need remains for patients treated after symptom onset. AREAS COVERED Drugs available in the clinic, investigational agents and key questions for researchers are discussed. A pragmatic search of the literature was performed to identify therapies in late stages of preclinical, or in early stages of clinical development. This list was compared to the CureSMA pipeline for completeness. Drugs approved for indications that have potential for impact for SMA were included. These drugs target the primary deficiency in SMN protein or other pathways involved in SMA pathophysiology that are not SMN-protein dependent. EXPERT OPINION Children treated after the onset of symptoms continue to have significant disability. Given the heterogeneity of the population phenotype evidenced by variable response to initial therapy, age at treatment onset and the need to demonstrate added value beyond approved therapeutics, the clinical development of new drugs will be challenging.
Collapse
Affiliation(s)
- Laurent Servais
- MDUK Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Neuromuscular Reference Center Disease, Department of Paediatrics, Liege, Belgium and University of Liege, Liège, Belgium
| | - Giovanni Baranello
- Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Mariacristina Scoto
- Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Aurore Daron
- Neuromuscular Reference Center Disease, Department of Paediatrics, Liege, Belgium and University of Liege, Liège, Belgium
| | - Maryam Oskoui
- Departments of Pediatrics and Neurology & Neurosurgery, McGill University, Montreal, QC, Canada
| |
Collapse
|
37
|
Gusset N, Stalens C, Stumpe E, Klouvi L, Mejat A, Ouillade MC, de Lemus M. Understanding European patient expectations towards current therapeutic development in spinal muscular atrophy. Neuromuscul Disord 2021; 31:419-430. [PMID: 33752935 DOI: 10.1016/j.nmd.2021.01.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 12/21/2022]
Abstract
Following the 2017 approval of a first spinal muscular atrophy (SMA) treatment by the European Medicines Agency, SMA Europe launched a Europe-wide survey with the goal of understanding patients' treatment expectations, realities of daily living and access to clinical trials and therapy, and how this varied according to parameters such as age and disease severity. A response rate of 31% yielded 1474 completed surveys from 26 European countries. In line with findings from a 2015 SMA Europe-led survey, participants considered stabilization of their condition to be progress. Notably, responses indicated that the current classification of SMA at diagnosis by 'type' often does not reflect current mobility level. Large gaps in treatment access were identified that varied in particular between age and disease severity groups, yet there was high interest in clinical trial participation. In addition, alternative treatment options, including combination therapies, are now expectations. These perspectives should be central considerations through the research and development processes of new SMA therapies, through data generation and discussions on access to therapies. Results from this survey indicate that collaboration between stakeholders is essential to the foundation upon which innovative approaches for SMA treatments and access can be explored.
Collapse
Affiliation(s)
- Nicole Gusset
- SMA Europe, Im Moos 4, 79112 Freiburg, Germany; SMA Schweiz, Alpenstrasse 76, CH - 3627 Heimberg, Switzerland.
| | | | - Eva Stumpe
- SMA Europe, Im Moos 4, 79112 Freiburg, Germany; Deutsche Gesellschaft für Muskelkranke, Im Moos 4, 79112 Freiburg, Germany
| | - Lori Klouvi
- AFM Telethon, 1 rue de l'Internationale, 91002 Evry, France
| | - Alexandre Mejat
- SMA Europe, Im Moos 4, 79112 Freiburg, Germany; AFM Telethon, 1 rue de l'Internationale, 91002 Evry, France
| | - Marie-Christine Ouillade
- SMA Europe, Im Moos 4, 79112 Freiburg, Germany; AFM Telethon, 1 rue de l'Internationale, 91002 Evry, France
| | - Mencía de Lemus
- SMA Europe, Im Moos 4, 79112 Freiburg, Germany; FundAME, Calle Antonio Miró Valverde, 5°G, 28055 Madrid, Spain
| |
Collapse
|
38
|
Motor unit reserve capacity in spinal muscular atrophy during fatiguing endurance performance. Clin Neurophysiol 2021; 132:800-807. [PMID: 33581592 DOI: 10.1016/j.clinph.2020.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/17/2020] [Accepted: 11/27/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To investigate the availability of any motor unit reserve capacity during fatiguing endurance testing in patients with spinal muscular atrophy (SMA). METHODS We recorded surface electromyography (sEMG) of various muscles of upper- and lower extremities of 70 patients with SMA types 2-4 and 19 healthy controls performing endurance shuttle tests (ESTs) of arm and legs. We quantitatively evaluated the development of fatigability and motor unit recruitment using time courses of median frequencies and amplitudes of sEMG signals. Linear mixed effect statistical models were used to evaluate group differences in median frequency and normalized amplitude at onset and its time course. RESULTS Normalized sEMG amplitudes at onset of upper body ESTs were significantly higher in patients compared to controls, yet submaximal when related to maximal voluntary contractions, and showed an inverse correlation to SMA phenotype. sEMG median frequencies decreased and amplitudes increased in various muscles during execution of ESTs in patients and controls. CONCLUSIONS Decreasing median frequencies and increasing amplitudes reveal motor unit reserve capacity in individual SMA patients during ESTs at submaximal performance intensities. SIGNIFICANCE Preserving, if not expanding motor unit reserve capacity may present a potential therapeutic target in clinical care to reduce fatigability in individual patients with SMA.
Collapse
|
39
|
In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:brainsci11020194. [PMID: 33562482 PMCID: PMC7915832 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
Collapse
|
40
|
Spinal muscular atrophy: Broad disease spectrum and sex-specific phenotypes. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166063. [PMID: 33412266 DOI: 10.1016/j.bbadis.2020.166063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% of cases of SMA result from deletions of or mutations in the Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. The spectrum of SMA is broad, ranging from prenatal death to infant mortality to survival into adulthood. All tissues, including brain, spinal cord, bone, skeletal muscle, heart, lung, liver, pancreas, gastrointestinal tract, kidney, spleen, ovary and testis, are directly and/or indirectly affected in SMA. Accumulating evidence on impaired mitochondrial biogenesis and defects in X chromosome-linked modifying factors, coupled with the sexual dimorphic nature of many tissues, point to sex-specific vulnerabilities in SMA. Here we review the role of sex in the pathogenesis of SMA.
Collapse
|
41
|
Vu-Han TL, Weiß C, Pumberger M. Novel therapies for spinal muscular atrophy are likely changing the patient phenotype. Spine J 2020; 20:1893-1898. [PMID: 32858169 DOI: 10.1016/j.spinee.2020.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Tu-Lan Vu-Han
- Center for Musculoskeletal Surgery Berlin Mitte; Charité University Medicine Berlin, Charitéplatz 1, Berlin 10117, Germany.
| | - Claudia Weiß
- Center for chronically sick children, Department of Neuropediatrics; Charité University, Medicine Berlin, Augustenburger Platz 1, Berlin 13353, Germany
| | - Matthias Pumberger
- Center for Musculoskeletal Surgery Berlin Mitte; Charité University Medicine Berlin, Charitéplatz 1, Berlin 10117, Germany
| |
Collapse
|
42
|
Anker MS, von Haehling S, Springer J. Blocking myostatin: muscle mass equals muscle strength? J Cachexia Sarcopenia Muscle 2020; 11:1396-1398. [PMID: 33340286 PMCID: PMC7749583 DOI: 10.1002/jcsm.12647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Markus S Anker
- Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany.,German Centre for Cardiovascular Research (DZHK) partner site Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany.,Division of Cardiology and Metabolism, Department of Cardiology (CVK), Charité University Medicine Berlin, Berlin, Germany.,Department of Cardiology (CBF), Charité University Medicine Berlin, Berlin, Germany
| | - Stephan von Haehling
- Department of Cardiology and Pneumology, University of Göttingen Medical Center and German Center for Cardiovascular Research (DZHK) partner site Göttingen, Göttingen, Germany
| | - Jochen Springer
- Berlin Institute of Health Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany.,German Centre for Cardiovascular Research (DZHK) partner site Berlin, Charité Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
43
|
Singh RN, Ottesen EW, Singh NN. The First Orally Deliverable Small Molecule for the Treatment of Spinal Muscular Atrophy. Neurosci Insights 2020; 15:2633105520973985. [PMID: 33283185 PMCID: PMC7691903 DOI: 10.1177/2633105520973985] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA) is 1 of the leading causes of infant mortality. SMA
is mostly caused by low levels of Survival Motor Neuron (SMN) protein due to
deletion of or mutation in the SMN1 gene. Its nearly identical
copy, SMN2, fails to compensate for the loss of
SMN1 due to predominant skipping of exon 7. Correction of
SMN2 exon 7 splicing by an antisense oligonucleotide (ASO),
nusinersen (Spinraza™), that targets the intronic splicing silencer N1 (ISS-N1)
became the first approved therapy for SMA. Restoration of SMN levels using gene
therapy was the next. Very recently, an orally deliverable small molecule,
risdiplam (Evrysdi™), became the third approved therapy for SMA. Here we discuss
how these therapies are positioned to meet the needs of the broad phenotypic
spectrum of SMA patients.
Collapse
Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| |
Collapse
|
44
|
Spinal muscular atrophy - insights and challenges in the treatment era. Nat Rev Neurol 2020; 16:706-715. [PMID: 33057172 DOI: 10.1038/s41582-020-00413-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2020] [Indexed: 01/05/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by deletion or mutation of SMN1. Four subtypes exist, characterized by different clinical severities. New therapeutic approaches have become available in the past few years, dramatically changing the natural history of all SMA subtypes, including substantial clinical improvement with the severe and advanced SMA type 1 variant. Trials have now demonstrated that phenotypic rescue is even more dramatic when pre-symptomatic patients are treated, and emerging real-world data are demonstrating the benefits of intervention even in the chronic phase of the condition. Here, we critically review how the field is rapidly evolving in response to the new therapies and questions that the new treatments have posed, including the effects of treatment at different ages and stages of disease, new phenotypes and long-term outcomes in patients who would not have survived without treatment, and decisions of who to treat and when. We also discuss how the outcomes associated with different timing of therapeutic intervention are contributing to our understanding of the biology and pathogenesis of SMA.
Collapse
|
45
|
Statins induce skeletal muscle atrophy via GGPP depletion-dependent myostatin overexpression in skeletal muscle and brown adipose tissue. Cell Biol Toxicol 2020; 37:441-460. [PMID: 33034787 DOI: 10.1007/s10565-020-09558-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 09/16/2020] [Indexed: 02/07/2023]
Abstract
Myopathy is the major adverse effect of statins. However, the underlying mechanism of statin-induced skeletal muscle atrophy, one of statin-induced myopathy, remains to be elucidated. Myostatin is a negative regulator of skeletal muscle mass and functions. Whether myostatin is involved in statin-induced skeletal muscle atrophy remains unknown. In this study, we uncovered that simvastatin administration increased serum myostatin levels in mice. Inhibition of myostatin with follistatin, an antagonist of myostatin, improved simvastatin-induced skeletal muscle atrophy. Simvastatin induced myostatin expression not only in skeletal muscle but also in brown adipose tissue (BAT). Mechanistically, simvastatin inhibited the phosphorylation of forkhead box protein O1 (FOXO1) in C2C12 myotubes, promoting the nuclear translocation of FOXO1 and thereby stimulating the transcription of myostatin. In differentiated brown adipocytes, simvastatin promoted myostatin expression mainly by inhibiting the expression of interferon regulatory factor 4 (IRF4). Moreover, the stimulative effect of simvastatin on myostatin expression was blunted by geranylgeranyl diphosphate (GGPP) supplementation in both myotubes and brown adipocytes, suggesting that GGPP depletion was attributed to simvastatin-induced myostatin expression. Besides, the capacities of statins on stimulating myostatin expression were positively correlated with the lipophilicity of statins. Our findings provide new insights into statin-induced skeletal muscle atrophy. Graphical headlights 1. Simvastatin induces skeletal muscle atrophy via increasing serum myostatin levels in mice; 2. Simvastatin promotes myostatin expression in both skeletal muscle and brown adipose tissue through inhibiting GGPP production; 3. The stimulating effect of statins on myostatin expression is positively correlated with the lipophilicity of statins.
Collapse
|
46
|
Chen TH. Comment on: "Myostatin inhibition in combination with antisense oligonucleotide therapy improves outcomes in spinal muscular atrophy" by Zhou et al. J Cachexia Sarcopenia Muscle 2020; 11:1377-1378. [PMID: 32716121 PMCID: PMC7567159 DOI: 10.1002/jcsm.12607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- Tai-Heng Chen
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100 Tzyou 1st Road, Kaohsiung, 80708, Taiwan
- Ph.D. Program in Translational Medicine, Graduate Institute of Clinical Medicine, Kaohsiung Medical University and Academia Sinica, Taipei, Taiwan
| |
Collapse
|
47
|
Zhou H, Muntoni F. The authors reply: Letter on: "Myostatin inhibition in combination with antisense oligonucleotide therapy improves outcomes in spinal muscular atrophy" by Zhou et al. J Cachexia Sarcopenia Muscle 2020; 11:1379-1380. [PMID: 32705767 PMCID: PMC7567137 DOI: 10.1002/jcsm.12608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 06/25/2020] [Indexed: 11/16/2022] Open
Affiliation(s)
- Haiyan Zhou
- Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Francesco Muntoni
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.,The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| |
Collapse
|
48
|
AAV9-DOK7 gene therapy reduces disease severity in Smn 2B/- SMA model mice. Biochem Biophys Res Commun 2020; 530:107-114. [PMID: 32828271 DOI: 10.1016/j.bbrc.2020.07.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/07/2020] [Indexed: 11/23/2022]
Abstract
Spinal Muscular Atrophy (SMA) is an autosomal recessive neuromuscular disease caused by deletions or mutations in the survival motor neuron (SMN1) gene. An important hallmark of disease progression is the pathology of neuromuscular junctions (NMJs). Affected NMJs in the SMA context exhibit delayed maturation, impaired synaptic transmission, and loss of contact between motor neurons and skeletal muscle. Protection and maintenance of NMJs remains a focal point of therapeutic strategies to treat SMA, and the recent implication of the NMJ-organizer Agrin in SMA pathology suggests additional NMJ organizing molecules may contribute. DOK7 is an NMJ organizer that functions downstream of Agrin. The potential of DOK7 as a putative therapeutic target was demonstrated by adeno-associated virus (AAV)-mediated gene therapy delivery of DOK7 in Amyotrophic Lateral Sclerosis (ALS) and Emery Dreyefuss Muscular Dystrophy (EDMD). To assess the potential of DOK7 as a disease modifier of SMA, we administered AAV-DOK7 to an intermediate mouse model of SMA. AAV9-DOK7 treatment conferred improvements in NMJ architecture and reduced muscle fiber atrophy. Additionally, these improvements resulted in a subtle reduction in phenotypic severity, evidenced by improved grip strength and an extension in survival. These findings reveal DOK7 is a novel modifier of SMA.
Collapse
|
49
|
Zhou H, Meng J, Malerba A, Catapano F, Sintusek P, Jarmin S, Feng L, Lu-Nguyen N, Sun L, Mariot V, Dumonceaux J, Morgan JE, Gissen P, Dickson G, Muntoni F. Myostatin inhibition in combination with antisense oligonucleotide therapy improves outcomes in spinal muscular atrophy. J Cachexia Sarcopenia Muscle 2020; 11:768-782. [PMID: 32031328 PMCID: PMC7296258 DOI: 10.1002/jcsm.12542] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by genetic defects in the survival motor neuron 1 (SMN1) gene that lead to SMN deficiency. Different SMN-restoring therapies substantially prolong survival and function in transgenic mice of SMA. However, these therapies do not entirely prevent muscle atrophy and restore function completely. To further improve the outcome, we explored the potential of a combinatorial therapy by modulating SMN production and muscle-enhancing approach as a novel therapeutic strategy for SMA. METHODS The experiments were performed in a mouse model of severe SMA. A previously reported 25-mer morpholino antisense oligomer PMO25 was used to restore SMN expression. The adeno-associated virus-mediated expression of myostatin propeptide was used to block the myostatin pathway. Newborn SMA mice were treated with a single subcutaneous injection of 40 μg/g (therapeutic dose) or 10 μg/g (low-dose) PMO25 on its own or together with systemic delivery of a single dose of adeno-associated virus-mediated expression of myostatin propeptide. The multiple effects of myostatin inhibition on survival, skeletal muscle phenotype, motor function, neuromuscular junction maturation, and proprioceptive afferences were evaluated. RESULTS We show that myostatin inhibition acts synergistically with SMN-restoring antisense therapy in SMA mice treated with the higher therapeutic dose PMO25 (40 μg/g), by increasing not only body weight (21% increase in male mice at Day 40), muscle mass (38% increase), and fibre size (35% increase in tibialis anterior muscle in 3 month female SMA mice), but also motor function and physical performance as measured in hanging wire test (two-fold increase in time score) and treadmill exercise test (two-fold increase in running distance). In SMA mice treated with low-dose PMO25 (10 μg/g), the early application of myostatin inhibition prolongs survival (40% increase), improves neuromuscular junction maturation (50% increase) and innervation (30% increase), and increases both the size of sensory neurons in dorsal root ganglia (60% increase) and the preservation of proprioceptive synapses in the spinal cord (30% increase). CONCLUSIONS These data suggest that myostatin inhibition, in addition to the well-known effect on muscle mass, can also positively influence the sensory neural circuits that may enhance motor neurons function. While the availability of the antisense drug Spinraza for SMA and other SMN-enhancing therapies has provided unprecedented improvement in SMA patients, there are still unmet needs in these patients. Our study provides further rationale for considering myostatin inhibitors as a therapeutic intervention in SMA patients, in combination with SMN-restoring drugs.
Collapse
Affiliation(s)
- Haiyan Zhou
- Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Jinhong Meng
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Alberto Malerba
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - Francesco Catapano
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Palittiya Sintusek
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,Department of Paediatrics, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand
| | - Susan Jarmin
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - Lucy Feng
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Ngoc Lu-Nguyen
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - Lianwen Sun
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Virginie Mariot
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Julie Dumonceaux
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Jennifer E Morgan
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Paul Gissen
- Genetics and Genomic Medicine Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - George Dickson
- Centres of Gene and Cell Therapy and Biomedical Sciences, School of Biological Sciences, Royal Holloway, University of London, Egham, UK
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Research and Teaching Department, Great Ormond Street Institute of Child Health, University College London, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| |
Collapse
|
50
|
New and Developing Therapies in Spinal Muscular Atrophy: From Genotype to Phenotype to Treatment and Where Do We Stand? Int J Mol Sci 2020; 21:ijms21093297. [PMID: 32392694 PMCID: PMC7246502 DOI: 10.3390/ijms21093297] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 02/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a congenital neuromuscular disorder characterized by motor neuron loss, resulting in progressive weakness. SMA is notable in the health care community because it accounts for the most common cause of infant death resulting from a genetic defect. SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from SMN1 gene mutations or deletions. However, patients always harbor various copies of SMN2, an almost identical but functionally deficient copy of the gene. A genotype–phenotype correlation suggests that SMN2 is a potent disease modifier for SMA, which also represents the primary target for potential therapies. Increasing comprehension of SMA pathophysiology, including the characterization of SMN1 and SMN2 genes and SMN protein functions, has led to the development of multiple therapeutic approaches. Until the end of 2016, no cure was available for SMA, and management consisted of supportive measures. Two breakthrough SMN-targeted treatments, either using antisense oligonucleotides (ASOs) or virus-mediated gene therapy, have recently been approved. These two novel therapeutics have a common objective: to increase the production of SMN protein in MNs and thereby improve motor function and survival. However, neither therapy currently provides a complete cure. Treating patients with SMA brings new responsibilities and unique dilemmas. As SMA is such a devastating disease, it is reasonable to assume that a unique therapeutic solution may not be sufficient. Current approaches under clinical investigation differ in administration routes, frequency of dosing, intrathecal versus systemic delivery, and mechanisms of action. Besides, emerging clinical trials evaluating the efficacy of either SMN-dependent or SMN-independent approaches are ongoing. This review aims to address the different knowledge gaps between genotype, phenotypes, and potential therapeutics.
Collapse
|