1
|
Alghanmi RM, Basha MT, Al-Sulami AI, Soliman SM, Abdel-Rahman LH. A New Proton Transfer Complex Between 3,4-Diaminopyridine Drug and 2,6-Dichloro-4-nitrophenol: Synthesis, Spectroscopic Characterization, DFT Studies, DNA Binding Analysis, and Antitumor Activity. Molecules 2024; 29:5120. [PMID: 39519761 PMCID: PMC11547504 DOI: 10.3390/molecules29215120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2024] [Revised: 10/22/2024] [Accepted: 10/28/2024] [Indexed: 11/16/2024] Open
Abstract
The proton transfer (PT) complexation reaction between 3,4-diaminopyridine (3,4-DAP), an important drug, and 2,6-dichloro-4-nitrphenole (DCNP) was investigated experimentally and theoretically. The experimental results indicated a chemical reaction occurred because of a hydrogen bonding, followed by proton transfer from the DCNP to the 3,4-DAP in different polar media. The Benesi-Hildebrand equation was used to estimate the formation constant (Kf), molar absorptivity (εPT), and other physical parameters. The formed PT complex was characterized using FTIR, 1H, and 13C NMR spectra. In addition, the nanocrystalline structure, particle sizes, and surface morphology of the complex were investigated by XRD and SEM-EDX. The structure of the 1:1 PT complex was calculated theoretically in the gas phase and the presence of solvent effects. Using TD-DFT calculations, the band observed at 406 nm (Calc. 379.5 nm) and 275 nm (Calc. 272.3 nm) could be assigned to the HOMO→LUMO transition (99%), and HOMO→L+3 transition (87%), respectively. The DNA binding ability of the PT complex was investigated, revealing an intercalative binding mechanism with a binding constant Kb of 4.6 × 104 M-1. Based on the results of the Ct-DNA binding study, the binding free energy of the PT complex with the receptor of human DNA (PDB ID:1BNA) is found to be -7.2 kcal/mol. The cytotoxic effects of the PT complex were evaluated on selected cancer cell lines, demonstrating significant antitumor activity against A-549 and MCF-7 cancer cell lines.
Collapse
Affiliation(s)
- Reem M. Alghanmi
- Department of Chemistry, College of Science, University of Jeddah, P.O. Box 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (A.I.A.-S.)
| | - Maram T. Basha
- Department of Chemistry, College of Science, University of Jeddah, P.O. Box 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (A.I.A.-S.)
| | - Ahlam I. Al-Sulami
- Department of Chemistry, College of Science, University of Jeddah, P.O. Box 80327, Jeddah 21589, Saudi Arabia; (M.T.B.); (A.I.A.-S.)
| | - Saied M. Soliman
- Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21525, Egypt;
| | | |
Collapse
|
2
|
Butenko O, Jensen SM, Fillié-Grijpma YE, Verpalen R, Verschuuren JJ, van der Maarel SM, Huijbers MG, Plomp JJ. Change of voltage-gated sodium channel repertoire in skeletal muscle of a MuSK myasthenia gravis mouse model. Eur J Neurosci 2024; 59:3292-3308. [PMID: 38650308 DOI: 10.1111/ejn.16347] [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: 09/15/2023] [Revised: 03/11/2024] [Accepted: 03/23/2024] [Indexed: 04/25/2024]
Abstract
Muscle-specific kinase myasthenia gravis (MuSK MG) is caused by autoantibodies against MuSK in the neuromuscular junction (NMJ). MuSK MG patients have fluctuating, fatigable skeletal muscle weakness, in particular of bulbar muscles. Severity differs greatly between patients, in spite of comparable autoantibody levels. One explanation for inter-patient and inter-muscle variability in sensitivity might be variations in compensatory muscle responses. Previously, we developed a passive transfer mouse model for MuSK MG. In preliminary ex vivo experiments, we observed that muscle contraction of some mice, in particular those with milder myasthenia, had become partially insensitive to inhibition by μ-Conotoxin-GIIIB, a blocker of skeletal muscle NaV1.4 voltage-gated sodium channels. We hypothesised that changes in NaV channel expression profile, possibly co-expression of (μ-Conotoxin-GIIIB insensitive) NaV1.5 type channels, might lower the muscle fibre's firing threshold and facilitate neuromuscular synaptic transmission. To test this hypothesis, we here performed passive transfer in immuno-compromised mice, using 'high', 'intermediate' and 'low' dosing regimens of purified MuSK MG patient IgG4. We compared myasthenia levels, μ-Conotoxin-GIIIB resistance and muscle fibre action potential characteristics and firing thresholds. High- and intermediate-dosed mice showed clear, progressive myasthenia, not seen in low-dosed animals. However, diaphragm NMJ electrophysiology demonstrated almost equal myasthenic severities amongst all regimens. Nonetheless, low-dosed mouse diaphragms showed a much higher degree of μ-Conotoxin-GIIIB resistance. This was not explained by upregulation of Scn5a (the NaV1.5 gene), lowered muscle fibre firing thresholds or histologically detectable upregulated NaV1.5 channels. It remains to be established which factors are responsible for the observed μ-Conotoxin-GIIIB insensitivity and whether the NaV repertoire change is compensatory beneficial or a bystander effect.
Collapse
Affiliation(s)
- Olena Butenko
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stine Marie Jensen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Robyn Verpalen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
3
|
Qaisar R. Targeting neuromuscular junction to treat neuromuscular disorders. Life Sci 2023; 333:122186. [PMID: 37858716 DOI: 10.1016/j.lfs.2023.122186] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
The integrity and preservation of the neuromuscular junction (NMJ), the interface between the motor neuron and skeletal muscle, is critical for maintaining a healthy skeletal muscle. The structural and/or functional defects in the three cellular components of NMJ, namely the pre-synaptic terminal, synaptic cleft, and post-synaptic region, negatively affect skeletal muscle mass and/or strength. Therefore, NMJ repair appears to be an appropriate therapy for muscle disorders. Mouse models provide a detailed molecular characterization of various cellular components of NMJ with relevance to human diseases. This review discusses different molecular targets on the three cellular components of NMJ for treating muscle diseases. The potential effects of these therapies on NMJ morphology and motor performance, their therapeutic efficacy, and clinical relevance are discussed. Collectively, the available data supports targeting NMJ alone or as an adjunct therapy in treating muscle disorders. However, the potential impact of such interventions on human patients with muscle disorders requires further investigation.
Collapse
Affiliation(s)
- Rizwan Qaisar
- Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Space Medicine Research Group, Sharjah Institute for Medical and Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates; Cardiovascular Research Group, Sharjah Institute for Medical and Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates.
| |
Collapse
|
4
|
Wang X, Burke SRA, Talmadge RJ, Voss AA, Rich MM. Depressed neuromuscular transmission causes weakness in mice lacking BK potassium channels. J Gen Physiol 2021; 152:151617. [PMID: 32243496 PMCID: PMC7201880 DOI: 10.1085/jgp.201912526] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/27/2020] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
Mice lacking functional large-conductance voltage- and Ca2+-activated K+ channels (BK channels) are viable but have motor deficits including ataxia and weakness. The cause of weakness is unknown. In this study, we discovered, in vivo, that skeletal muscle in mice lacking BK channels (BK−/−) was weak in response to nerve stimulation but not to direct muscle stimulation, suggesting a failure of neuromuscular transmission. Voltage-clamp studies of the BK−/− neuromuscular junction (NMJ) revealed a reduction in evoked endplate current amplitude and the frequency of spontaneous vesicle release compared with WT littermates. Responses to 50-Hz stimulation indicated a reduced probability of vesicle release in BK−/− mice, suggestive of lower presynaptic Ca2+ entry. Pharmacological block of BK channels in WT NMJs did not affect NMJ function, surprisingly suggesting that the reduced vesicle release in BK−/− NMJs was not due to loss of BK channel–mediated K+ current. Possible explanations for our data include an effect of BK channels on development of the NMJ, a role for BK channels in regulating presynaptic Ca2+ current or the effectiveness of Ca2+ in triggering release. Consistent with reduced Ca2+ entry or effectiveness of Ca2+ in triggering release, use of 3,4-diaminopyridine to widen action potentials normalized evoked release in BK−/− mice to WT levels. Intraperitoneal application of 3,4-diaminopyridine fully restored in vivo nerve-stimulated muscle force in BK−/− mice. Our work demonstrates that mice lacking BK channels have weakness due to a defect in vesicle release at the NMJ.
Collapse
Affiliation(s)
- Xueyong Wang
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH
| | - Steven R A Burke
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH
| |
Collapse
|
5
|
Alghanmi RM, Basha MT, Soliman SM, Alsaeedi RK. Synthesis, and spectroscopic, nanostructure, surface morphology, and density functional theory studies of new charge-transfer complexes of amifampridine with π-acceptors. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115199] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
6
|
Rivner MH, Pasnoor M, Dimachkie MM, Barohn RJ, Mei L. Muscle-Specific Tyrosine Kinase and Myasthenia Gravis Owing to Other Antibodies. Neurol Clin 2019; 36:293-310. [PMID: 29655451 DOI: 10.1016/j.ncl.2018.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Around 20% of patients with myasthenia gravis are acetylcholine receptor antibody negative; muscle-specific tyrosine kinase antibodies (MuSK) were identified as the cause of myasthenia gravis in 30% to 40% of these cases. Anti MuSK myasthenia gravis is associated with specific clinical phenotypes. One is a bulbar form with fewer ocular symptoms. Others show an isolated head drop or symptoms indistinguishable from acetylcholine receptor-positive myasthenia gravis. These patients usually respond well to immunosuppressive therapy, but not as well to cholinesterase inhibitors. Other antibodies associated with myasthenia gravis, including low-density lipoprotein receptor-related protein 4, are discussed.
Collapse
Affiliation(s)
- Michael H Rivner
- EMG Lab, Augusta University, 1120 15th Street, BP-4390, Augusta, GA 30912, USA.
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Mazen M Dimachkie
- Department of Neurology, University of Kansas Medical Center, 3599 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66103, USA
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 4017, Kansas City, KS 66160, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Augusta University, 1120 15th Street, CA-2014, Augusta, GA 30912, USA
| |
Collapse
|
7
|
Abstract
This article discusses antibodies associated with immune-mediated myasthenia gravis and the pathologic action of these antibodies at the neuromuscular junctions of skeletal muscle. To explain how these antibodies act, we consider the physiology of neuromuscular transmission with emphasis on 4 features: the structure of the neuromuscular junction; the roles of postsynaptic acetylcholine receptors and voltage-gated Na+ channels and in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber that triggers muscle contraction; the safety factor for neuromuscular transmission; and how the safety factor is reduced in different forms of autoimmune myasthenia gravis.
Collapse
Affiliation(s)
- Robert L Ruff
- Department of Neurology, Case Western University School of Medicine, The Metro Health System, 2500 Metro Health Drive, Cleveland, OH 44109, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Robert P Lisak
- Department of Neurology, Wayne State University School of Medicine, 8D University Health Center, 4201 St Antoine, Detroit, MI 48201, USA; Department of Biochemistry, Microbiology and Immunology, Wayne State University, Detroit, MI, USA.
| |
Collapse
|
8
|
Abstract
Neuromuscular junctions (NMJs) form between nerve terminals of spinal cord motor neurons and skeletal muscles, and perisynaptic Schwann cells and kranocytes cap NMJs. One muscle fiber has one NMJ, which is innervated by one motor nerve terminal. NMJs are excitatory synapses that use P/Q-type voltage-gated calcium channels to release the neurotransmitter acetylcholine. Acetylcholine receptors accumulate at the postsynaptic specialization called the end plate on the muscle fiber membrane, the sarcolemma. Proteins essential for the organization of end plates include agrin secreted from nerve terminals, Lrp4 and MuSK receptors for agrin, and Dok-7 and rapsyn cytosolic proteins in the muscle.
Collapse
Affiliation(s)
- Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, 3901 Rainbow Boulevard, MS 3051, Hemenway Room 2073, Kansas City, KS 66160, USA.
| | - Kazuhiro Shigemoto
- Research Team for Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Sakae-cho 35-2, Itabashi-ku, Tokyo 173-0015, Japan
| |
Collapse
|
9
|
Hoolachan JM, Sutton ER, Bowerman M. Teaching an old drug new tricks: repositioning strategies for spinal muscular atrophy. FUTURE NEUROLOGY 2019. [DOI: 10.2217/fnl-2019-0006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a childhood disorder caused by loss of the SMN gene. Pathological hallmarks are spinal cord motor neuron death, neuromuscular junction dysfunction and muscle atrophy. The first SMN genetic therapy was recently approved and other SMN-dependent treatments are not far behind. However, not all SMA patients will reap their maximal benefit due to limited accessibility, high costs and differential effects depending on timing of administration and disease severity. The repurposing of commercially available drugs is an interesting strategy to ensure more rapid and less expensive access to new treatments. In this mini-review, we will discuss the potential and relevance of repositioning drugs currently used for neurodegenerative, neuromuscular and muscle disorders for SMA.
Collapse
Affiliation(s)
- Joseph M Hoolachan
- School of Medicine, Keele University, Staffordshire, ST5 5BG, UK
- School of Pharmacy and Bioengineering, Keele University, Staffordshire, ST5 5BG, UK
| | - Emma R Sutton
- School of Pharmacy and Bioengineering, Keele University, Staffordshire, ST5 5BG, UK
| | - Melissa Bowerman
- School of Medicine, Keele University, Staffordshire, ST5 5BG, UK
- School of Pharmacy and Bioengineering, Keele University, Staffordshire, ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK
| |
Collapse
|
10
|
Bonanno S, Pasanisi MB, Frangiamore R, Maggi L, Antozzi C, Andreetta F, Campanella A, Brenna G, Cottini L, Mantegazza R. Amifampridine phosphate in the treatment of muscle-specific kinase myasthenia gravis: a phase IIb, randomized, double-blind, placebo-controlled, double crossover study. SAGE Open Med 2018; 6:2050312118819013. [PMID: 30574306 PMCID: PMC6299310 DOI: 10.1177/2050312118819013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/21/2018] [Indexed: 11/16/2022] Open
Abstract
Objective: The aim of this study is to determine the safety and the efficacy of amifampridine phosphate in muscle-specific kinase antibody-positive myasthenia gravis, in a 1:1 randomized, double-blind, placebo-controlled, switchback, double crossover study. Methods: Eligible patients had muscle-specific kinase myasthenia gravis, >18 years of age, and Myasthenia Gravis Foundation of America class II–IV with a score of ⩾9 on Myasthenia Gravis Composite scale. After the run-in phase, during which amifampridine phosphate was titrated to a tolerable and effective dosage, patients were randomized to receive placebo–amifampridine–placebo sequence or amifampridine–placebo–amifampridine sequence daily for 7 days. Then, patients switched treatment arms twice, for a total of 21 days of double-blind treatment. Safety was determined by serial assessments of adverse events/serious adverse events, physical examinations, and clinical and laboratory tests. The co-primary outcome measures included changes from baseline of Quantitative Myasthenia Gravis score and Myasthenia Gravis–specific Activities of Daily Living Profile score. The secondary outcome measures comprised changes from baseline of Myasthenia Gravis Composite score, Myasthenia Gravis Quality of Life scale—15 questions, Fatigue Severity Scale, and Carlo Besta Neurological Institute–Myasthenia Gravis scale. Statistical analyses were assessed using a switchback model for three-period, two-treatment crossover design. Results: A total of 10 patients were screened, enrolled, and treated. Transient paresthesias (60%) were the only amifampridine phosphate–related adverse events reported. Four patients were randomized to receive placebo–amifampridine–placebo sequence and three patients to receive amifampridine–placebo–amifampridine sequence. The co-primary objectives were statistically met (Quantitative Myasthenia Gravis score: p = 0.0003 and Myasthenia Gravis–specific Activities of Daily Living Profile score: p = 0.0006), as well as all the secondary endpoints (Myasthenia Gravis Composite score: p < 0.0001, Myasthenia Gravis Quality of Life scale—15 questions: p = 0.0025, Fatigue Severity Scale: p = 0.0061, and Carlo Besta Neurological Institute–Myasthenia Gravis scale: p = 0.0014). Conclusion: Despite the low number of patients, MuSK-001 study provided evidence that amifampridine phosphate, in the range of 30–60 mg daily dose, was safe and effective in treating muscle-specific kinase myasthenia gravis, suggesting the need for a large multi-center trial to confirm these results.
Collapse
Affiliation(s)
- Silvia Bonanno
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Maria Barbara Pasanisi
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Rita Frangiamore
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Lorenzo Maggi
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Carlo Antozzi
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Francesca Andreetta
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Angela Campanella
- Department of Clinical Research and Innovation, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | | | | | - Renato Mantegazza
- Department of Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy.,Department of Clinical Research and Innovation, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| |
Collapse
|
11
|
Karam C, Dimitrova D. Lack of benefit Of 3,4-Diaminopyridine in MuSK+MG. Muscle Nerve 2018; 58:E33-E34. [DOI: 10.1002/mus.26180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Chafic Karam
- Department of Neurology; Oregon Health & Science University; Portland Oregon USA
| | - Diana Dimitrova
- Department of Neurology; Oregon Health & Science University; Portland Oregon USA
| |
Collapse
|
12
|
Morren J, Li Y. Myasthenia gravis with muscle-specific tyrosine kinase antibodies: A narrative review. Muscle Nerve 2018; 58:344-358. [DOI: 10.1002/mus.26107] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/09/2018] [Accepted: 02/18/2018] [Indexed: 12/14/2022]
Affiliation(s)
- John Morren
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
| | - Yuebing Li
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
| |
Collapse
|
13
|
de Wilde S, de Jong MGH, Lipka AF, Guchelaar HJ, Schimmel KJM. The possibility of obtaining marketing authorization of orphan pharmaceutical compounding preparations: 3,4-DAP for Lambert-Eaton Myasthenic Syndrome. Eur J Pharm Sci 2018; 114:24-29. [PMID: 29191521 DOI: 10.1016/j.ejps.2017.11.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND Pharmaceutical compounding preparations, produced by (hospital) pharmacies, usually do not have marketing authorization. As a consequence, some of these pharmaceutical compounding preparations can be picked-up by a pharmaceutical company to obtain marketing authorization, often leading to price increases. An example is the 3,4-diaminopyridine slow release (3,4-DAP SR) tablets for Lambert-Eaton Myasthenic Syndrome (LEMS). In 2009 marketing authorization was given for the commercial immediate release phosphate salt of the drug, including a fifty-fold price increase compared to the pharmaceutical compounding preparation. Obtaining marketing authorization for 3,4-DAP SR by academia might have been a solution to prevent this price increase. To determine whether the available data of a pharmaceutical compounding preparation with long-term experience in regular care are adequate to obtain marketing authorization, 3,4-DAP SR is used as a case study. METHODS A retrospective qualitative case-study was performed. Initially, document analysis was executed by collecting the required data for marketing authorization in general and whether data of Firdapse® and 3,4-DAP SR met these requirements. Secondly, the (non-) available data of the two formulations were compared with each other to determine the differences in availability. RESULTS At the time of approval, almost all data were available for both Firdapse® and 3,4-DAP SR. Conversely, much of the data used for the approval of Firdapse® originated from the 3,4-DAP immediate release (3,4-DAP IR) formulation. Only two bioequivalence studies and one pharmacology safety study was performed with Firdapse® before marketing authorization application. CONCLUSIONS In conclusion, at time Firdapse® obtained approval, the data available did not differ substantially from 3,4-DAP SR, indicating that approval with 3,4-DAP SR would have been possible. We make a plea for approval of orphan medicinal products developed and manufactured by academic institutions as to keep utilization of these products affordable.
Collapse
Affiliation(s)
- Sofieke de Wilde
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Maria G H de Jong
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands.
| | - Alexander F Lipka
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Henk-Jan Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Kirsten J M Schimmel
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
14
|
Nonclinical data supporting orphan medicinal product designations: lessons from rare neurological conditions. Drug Discov Today 2018; 23:26-48. [DOI: 10.1016/j.drudis.2017.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/01/2017] [Accepted: 09/27/2017] [Indexed: 12/14/2022]
|
15
|
Ghazanfari N, Trajanovska S, Morsch M, Liang SX, Reddel SW, Phillips WD. The mouse passive-transfer model of MuSK myasthenia gravis: disrupted MuSK signaling causes synapse failure. Ann N Y Acad Sci 2017; 1412:54-61. [DOI: 10.1111/nyas.13513] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/05/2017] [Accepted: 09/09/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Nazanin Ghazanfari
- Physiology and Bosch Institute; University of Sydney; Sydney New South Wales Australia
| | - Sofie Trajanovska
- Physiology and Bosch Institute; University of Sydney; Sydney New South Wales Australia
| | - Marco Morsch
- Physiology and Bosch Institute; University of Sydney; Sydney New South Wales Australia
- Department of Biomedical Sciences; Macquarie University; Sydney New South Wales Australia
| | - Simon X. Liang
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences; Liaoning Medical University; Jinzhou China
| | - Stephen W. Reddel
- Department of Molecular Medicine; Concord Hospital; Sydney New South Wales Australia
| | - William D. Phillips
- Physiology and Bosch Institute; University of Sydney; Sydney New South Wales Australia
| |
Collapse
|
16
|
Mori S, Motohashi N, Takashima R, Kishi M, Nishimune H, Shigemoto K. Immunization of mice with LRP4 induces myasthenia similar to MuSK-associated myasthenia gravis. Exp Neurol 2017; 297:158-167. [PMID: 28823823 DOI: 10.1016/j.expneurol.2017.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/11/2017] [Accepted: 08/11/2017] [Indexed: 12/21/2022]
Abstract
Since the first report of experimental animal models of myasthenia gravis (MG) with autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4), there have not been any major reports replicating the pathogenicity of anti-LRP4 antibodies (Abs). Recent clinical studies have cast doubt on the specificity and pathogenicity of anti-LRP4 antibodies for MG, highlighting the need for further research. In this study, we purified antigens corresponding to the extracellular region of human LRP4 stably expressed with chaperones in 293 cells and used these antigens to immunize female A/J mice. Immunization with LRP4 protein caused mice to develop myasthenia having similar electrophysiological and histological features as are observed in MG patients with circulating Abs against muscle-specific kinase (MuSK). Our results clearly demonstrate that active immunization of mice with LRP4 proteins causes myasthenia similar to the MG induced by anti-MuSK Abs. Further experimental and clinical studies are required to prove the pathogenicity of anti-LRP4 Abs in MG patients.
Collapse
Affiliation(s)
- Shuuichi Mori
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Norio Motohashi
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Rumi Takashima
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Masahiko Kishi
- Department of Internal Medicine, Toho University Sakura Medical Center, Chiba, Japan
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, United States
| | - Kazuhiro Shigemoto
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
| |
Collapse
|
17
|
Ng F, Lee DC, Schrumpf LA, Mazurek ME, Lee Lo V, Gill SK, Maselli RA. Effect of 3,4-diaminopyridine at the murine neuromuscular junction. Muscle Nerve 2016; 55:223-231. [PMID: 27251582 DOI: 10.1002/mus.25208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/19/2016] [Accepted: 05/31/2016] [Indexed: 11/09/2022]
Abstract
INTRODUCTION We investigated the effects of 3,4-diaminopyridine (3,4-DAP) and its acetylated metabolite, N-(4-amino-pyridin-3-yl) acetamide (3-Ac), at the mammalian neuromuscular junction. METHODS Quantal release of acetylcholine was studied in diaphragm muscles of mice, using in vitro intracellular microelectrode recordings. RESULTS Under conditions of low probability of release, 3,4-DAP produced a 1,000% increase in quantal release, but 3-Ac had no effect. Under conditions of normal probability of release, the effect of 3,4-DAP was modest and limited by concurrent depletion of synaptic vesicles, especially with high concentrations of 3,4-DAP and high frequencies of nerve stimulation. CONCLUSIONS These findings predict 3,4-DAP is most effective in conditions with low probability of quantal release, such as Lambert-Eaton myasthenic syndrome. A beneficial effect is also expected in disorders of neuromuscular transmission in which the effect of 3,4-DAP on quantal release is not limited by depletion of synaptic vesicles, such as postsynaptic congenital myasthenic syndromes. Muscle Nerve, 2016 Muscle Nerve 55: 223-231, 2017.
Collapse
Affiliation(s)
- Fiona Ng
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Diana C Lee
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Leah A Schrumpf
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Mary E Mazurek
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Victoria Lee Lo
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Sharleen K Gill
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| | - Ricardo A Maselli
- University of California, Davis School of Medicine Department of Neurology, University of California Davis, Davis, California, USA
| |
Collapse
|
18
|
Evoli A, Alboini PE, Damato V, Iorio R. 3,4-Diaminopyridine may improve myasthenia gravis with MuSK antibodies. Neurology 2016; 86:1070-1. [DOI: 10.1212/wnl.0000000000002466] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/12/2015] [Indexed: 11/15/2022] Open
|
19
|
Plomp JJ, Morsch M, Phillips WD, Verschuuren JJGM. Electrophysiological analysis of neuromuscular synaptic function in myasthenia gravis patients and animal models. Exp Neurol 2015; 270:41-54. [PMID: 25620417 DOI: 10.1016/j.expneurol.2015.01.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/07/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022]
Abstract
Study of the electrophysiological function of the neuromuscular junction (NMJ) is instrumental in the understanding of the symptoms and pathophysiology of myasthenia gravis (MG), an autoimmune disorder characterized by fluctuating and fatigable muscle weakness. Most patients have autoantibodies to the acetylcholine receptor at the NMJ. However, in recent years autoantibodies to other crucial postsynaptic membrane proteins have been found in previously 'seronegative' MG patients. Electromyographical recording of compound and single-fibre muscle action potentials provides a crucial in vivo method to determine neuromuscular transmission failure while ex vivo (miniature) endplate potential recordings can reveal the precise synaptic impairment. Here we will review these electrophysiological methods used to assess NMJ function and discuss their application and typical results found in the diagnostic and experimental study of patients and animal models of the several forms of MG.
Collapse
Affiliation(s)
- Jaap J Plomp
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.
| | - Marco Morsch
- Motor Neuron Disease Research Group, Macquarie University, Sydney, Australia
| | | | | |
Collapse
|
20
|
Evoli A, Iorio R. Characteristics of myasthenia gravis with antibodies to muscle-specific kinase and low-density lipoprotein-related receptor protein 4. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/cen3.12173] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Amelia Evoli
- Institute of Neurology; Catholic University; Roma Italy
| | | |
Collapse
|
21
|
Phillips WD, Christadoss P, Losen M, Punga AR, Shigemoto K, Verschuuren J, Vincent A. Guidelines for pre-clinical animal and cellular models of MuSK-myasthenia gravis. Exp Neurol 2014; 270:29-40. [PMID: 25542979 DOI: 10.1016/j.expneurol.2014.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/12/2014] [Accepted: 12/17/2014] [Indexed: 11/17/2022]
Abstract
Muscle-specific tyrosine kinase (MuSK) autoantibodies are the hallmark of a form of myasthenia gravis (MG) that can challenge the neurologist and the experimentalist. The clinical disease can be difficult to treat effectively. MuSK autoantibodies affect the neuromuscular junction in several ways. When added to muscle cells in culture, MuSK antibodies disperse acetylcholine receptor clusters. Experimental animals actively immunized with MuSK develop MuSK autoantibodies and muscle weakness. Weakness is associated with reduced postsynaptic acetylcholine receptor numbers, reduced amplitudes of miniature endplate potentials and endplate potentials, and failure of neuromuscular transmission. Similar impairments have been found in mice injected with IgG from MG patients positive for MuSK autoantibody (MuSK-MG). The active and passive models have begun to reveal the mechanisms by which MuSK antibodies disrupt synaptic function at the neuromuscular junction, and should be valuable in developing therapies for MuSK-MG. However, translation into new and improved treatments for patients requires procedures that are not too cumbersome but suitable for examining different aspects of MuSK function and the effects of potential therapies. Study design, conduct and analysis should be carefully considered and transparently reported. Here we review what has been learnt from animal and culture models of MuSK-MG, and offer guidelines for experimental design and conduct of studies, including sample size determination, randomization, outcome parameters and precautions for objective data analysis. These principles may also be relevant to the increasing number of other antibody-mediated diseases that are now recognized.
Collapse
Affiliation(s)
- W D Phillips
- School of Medical Sciences (Physiology) and Bosch Institute, Anderson Stuart Bldg (F13), University of Sydney, NSW 2006, Australia.
| | - P Christadoss
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - M Losen
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - A R Punga
- Institute of Neuroscience, Department of Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
| | - K Shigemoto
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
| | - J Verschuuren
- Department of Neurology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands.
| | - A Vincent
- Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
22
|
Patel V, Oh A, Voit A, Sultatos LG, Babu GJ, Wilson BA, Ho M, McArdle JJ. Altered active zones, vesicle pools, nerve terminal conductivity, and morphology during experimental MuSK myasthenia gravis. PLoS One 2014; 9:e110571. [PMID: 25438154 PMCID: PMC4249869 DOI: 10.1371/journal.pone.0110571] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/15/2014] [Indexed: 11/18/2022] Open
Abstract
Recent studies demonstrate reduced motor-nerve function during autoimmune muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG). To further understand the basis of motor-nerve dysfunction during MuSK-MG, we immunized female C57/B6 mice with purified rat MuSK ectodomain. Nerve-muscle preparations were dissected and neuromuscular junctions (NMJs) studied electrophysiologically, morphologically, and biochemically. While all mice produced antibodies to MuSK, only 40% developed respiratory muscle weakness. In vitro study of respiratory nerve-muscle preparations isolated from these affected mice revealed that 78% of NMJs produced endplate currents (EPCs) with significantly reduced quantal content, although potentiation and depression at 50 Hz remained qualitatively normal. EPC and mEPC amplitude variability indicated significantly reduced number of vesicle-release sites (active zones) and reduced probability of vesicle release. The readily releasable vesicle pool size and the frequency of large amplitude mEPCs also declined. The remaining NMJs had intermittent (4%) or complete (18%) failure of neurotransmitter release in response to 50 Hz nerve stimulation, presumably due to blocked action potential entry into the nerve terminal, which may arise from nerve terminal swelling and thinning. Since MuSK-MG-affected muscles do not express the AChR γ subunit, the observed prolongation of EPC decay time was not due to inactivity-induced expression of embryonic acetylcholine receptor, but rather to reduced catalytic activity of acetylcholinesterase. Muscle protein levels of MuSK did not change. These findings provide novel insight into the pathophysiology of autoimmune MuSK-MG.
Collapse
MESH Headings
- Animals
- Female
- Immunization, Passive
- Mice
- Motor Endplate/pathology
- Motor Endplate/physiopathology
- Motor Neurons/pathology
- Myasthenia Gravis, Autoimmune, Experimental/immunology
- Myasthenia Gravis, Autoimmune, Experimental/metabolism
- Myasthenia Gravis, Autoimmune, Experimental/pathology
- Myasthenia Gravis, Autoimmune, Experimental/physiopathology
- Neural Conduction
- Neurotransmitter Agents/metabolism
- Protein Structure, Tertiary
- Rats
- Receptor Protein-Tyrosine Kinases/chemistry
- Receptor Protein-Tyrosine Kinases/immunology
- Receptors, Cholinergic/metabolism
- Synaptic Vesicles/metabolism
- Vaccination
Collapse
Affiliation(s)
- Vishwendra Patel
- Department of Pharmacology and Physiology, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
| | - Anne Oh
- Department of Pharmacology and Physiology, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
| | - Antanina Voit
- Department Cell Biology and Molecular Medicine, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
| | - Lester G. Sultatos
- Department of Pharmacology and Physiology, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
| | - Gopal J. Babu
- Department Cell Biology and Molecular Medicine, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
| | - Brenda A. Wilson
- Department of Microbiology, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Mengfei Ho
- Department of Microbiology, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Joseph J. McArdle
- Department of Pharmacology and Physiology, New Jersey Medical School-Rutgers University, Newark, New Jersey, United States of America
- * E-mail:
| |
Collapse
|
23
|
Expression of extracellular domains of muscle specific kinase (MuSK) and use as immunoadsorbents for the development of an antigen-specific therapy. J Neuroimmunol 2014; 276:150-8. [PMID: 25262156 DOI: 10.1016/j.jneuroim.2014.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/12/2014] [Indexed: 12/17/2022]
Abstract
Antibodies against MuSK seem to be the pathogenic factor in approximately 5-8% of myasthenia gravis (MG) patients. We aim to develop an antigen-specific therapy in which only MuSK antibodies will be removed from patients' plasma using MuSK extracellular domain (MuSK-ECD) as immunoadsorbent. We showed that two different immunoadsorbents, very efficiently and selectively depleted the MuSK antibodies from all tested sera, were stable during the procedure and were reusable. Furthermore, animal experiments showed that the treatment has no toxic effects to the animals. We conclude that the MuSK-ECD-mediated immunoadsorption can be used as an efficient antigen-specific therapy for MuSK-MG.
Collapse
|
24
|
Tarr TB, Lacomis D, Reddel SW, Liang M, Valdomir G, Frasso M, Wipf P, Meriney SD. Complete reversal of Lambert-Eaton myasthenic syndrome synaptic impairment by the combined use of a K+ channel blocker and a Ca2+ channel agonist. J Physiol 2014; 592:3687-96. [PMID: 25015919 DOI: 10.1113/jphysiol.2014.276493] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder in which a significant fraction of the presynaptic P/Q-type Ca(2+) channels critical to the triggering of neurotransmitter release at the neuromuscular junction (NMJ) are thought to be removed. There is no cure for LEMS, and the current most commonly used symptomatic treatment option is a potassium channel blocker [3,4-diaminopyridine (3,4-DAP)] that does not completely reverse symptoms and can have dose-limiting side-effects. We previously reported the development of a novel Ca(2+) channel agonist, GV-58, as a possible alternative treatment strategy for LEMS. In this study, we tested the hypothesis that the combination of GV-58 and 3,4-DAP will elicit a supra-additive increase in neurotransmitter release at LEMS model NMJs. First, we tested GV-58 in a cell survival assay to assess potential effects on cyclin-dependent kinases (Cdks) and showed that GV-58 did not affect cell survival at the relevant concentrations for Ca(2+) channel effects. Then, we examined the voltage dependence of GV-58 effects on Ca(2+) channels using patch clamp techniques; this showed the effects of GV-58 to be dependent upon Ca(2+) channel opening. Based on this mechanism, we predicted an interaction between 3,4-DAP and GV-58. We tested this hypothesis using a mouse passive transfer model of LEMS. Using intracellular electrophysiological ex vivo recordings, we demonstrated that a combined application of 3,4-DAP plus GV-58 had a supra-additive effect that completely reversed the deficit in neurotransmitter release magnitude at LEMS model NMJs. This reversal contrasts with the less significant improvement observed with either compound alone. Our data indicate that a combination of 3,4-DAP and GV-58 represents a promising treatment option for LEMS and potentially for other disorders of the NMJ.
Collapse
Affiliation(s)
- Tyler B Tarr
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - David Lacomis
- Division of Neuromuscular Diseases, Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen W Reddel
- Department of Clinical Neurology, Concord Hospital, Sydney, NSW, Australia
| | - Mary Liang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, PA, USA
| | - Guillermo Valdomir
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Frasso
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen D Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
25
|
Shi Y, Ivannikov MV, Walsh ME, Liu Y, Zhang Y, Jaramillo CA, Macleod GT, Van Remmen H. The lack of CuZnSOD leads to impaired neurotransmitter release, neuromuscular junction destabilization and reduced muscle strength in mice. PLoS One 2014; 9:e100834. [PMID: 24971750 PMCID: PMC4074103 DOI: 10.1371/journal.pone.0100834] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/29/2014] [Indexed: 11/29/2022] Open
Abstract
Elevated reactive oxygen species (ROS) production and ROS-dependent protein damage is a common observation in the pathogenesis of many muscle wasting disorders, including sarcopenia. However, the contribution of elevated ROS levels to –a breakdown in neuromuscular communication and muscle atrophy remains unknown. In this study, we examined a copper zinc superoxide dismutase [CuZnSOD (Sod1)] knockout mouse (Sod1−/−), a mouse model of elevated oxidative stress that exhibits accelerated loss of muscle mass, which recapitulates many phenotypes of sarcopenia as early as 5 months of age. We found that young adult Sod1−/− mice display a considerable reduction in hind limb skeletal muscle mass and strength when compared to age-matched wild-type mice. These changes are accompanied by gross alterations in neuromuscular junction (NMJ) morphology, including reduced occupancy of the motor endplates by axons, terminal sprouting and axon thinning and irregular swelling. Surprisingly however, the average density of acetylcholine receptors in endplates is preserved. Using in vivo electromyography and ex vivo electrophysiological studies of hind limb muscles in Sod1−/− mice, we found that motor axons innervating the extensor digitorum longus (EDL) and gastrocnemius muscles release fewer synaptic vesicles upon nerve stimulation. Recordings from individually identified EDL NMJs show that reductions in neurotransmitter release are apparent in the Sod1−/− mice even when endplates are close to fully innervated. However, electrophysiological properties, such as input resistance, resting membrane potential and spontaneous neurotransmitter release kinetics (but not frequency) are similar between EDL muscles of Sod1−/− and wild-type mice. Administration of the potassium channel blocker 3,4-diaminopyridine, which broadens the presynaptic action potential, improves both neurotransmitter release and muscle strength. Together, these results suggest that ROS-associated motor nerve terminal dysfunction is a contributor to the observed muscle changes in Sod1−/− mice.
Collapse
Affiliation(s)
- Yun Shi
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
| | - Maxim V. Ivannikov
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Michael E. Walsh
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Yuhong Liu
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
| | - Yiqiang Zhang
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Carlos A. Jaramillo
- Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
- Department of Rehabilitation Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Gregory T. Macleod
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Holly Van Remmen
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Oklahoma City VA Medical Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
| |
Collapse
|
26
|
Lindquist S, Stangel M. 3,4-Diaminopyridine (amifampridine) for the treatment of Lambert–Eaton myasthenic syndrome. Expert Opin Orphan Drugs 2014. [DOI: 10.1517/21678707.2014.887464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
27
|
|
28
|
|
29
|
|
30
|
Evaluation of a novel calcium channel agonist for therapeutic potential in Lambert-Eaton myasthenic syndrome. J Neurosci 2013; 33:10559-67. [PMID: 23785168 DOI: 10.1523/jneurosci.4629-12.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We developed a novel calcium (Ca(2+)) channel agonist that is selective for N- and P/Q-type Ca(2+) channels, which are the Ca(2+) channels that regulate transmitter release at most synapses. We have shown that this new molecule (GV-58) slows the deactivation of channels, resulting in a large increase in presynaptic Ca(2+) entry during activity. GV-58 was developed as a modification of (R)-roscovitine, which was previously shown to be a Ca(2+) channel agonist, in addition to its known cyclin-dependent kinase activity. In comparison with the parent molecule, (R)-roscovitine, GV-58 has a ∼20-fold less potent cyclin-dependent kinase antagonist effect, a ∼3- to 4-fold more potent Ca(2+) channel agonist effect, and ∼4-fold higher efficacy as a Ca(2+) channel agonist. We have further evaluated GV-58 in a passive transfer mouse model of Lambert-Eaton myasthenic syndrome and have shown that weakened Lambert-Eaton myasthenic syndrome-model neuromuscular synapses are significantly strengthened following exposure to GV-58. This new Ca(2+) channel agonist has potential as a lead compound in the development of new therapeutic approaches to a variety of disorders that result in neuromuscular weakness.
Collapse
|
31
|
Mechanisms associated with the pathogenicity of antibodies against muscle-specific kinase in myasthenia gravis. Autoimmun Rev 2013; 12:912-7. [DOI: 10.1016/j.autrev.2013.03.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 12/27/2022]
|
32
|
Richman DP, Nishi K, Ferns MJ, Schnier J, Pytel P, Maselli RA, Agius MA. Animal models of antimuscle-specific kinase myasthenia. Ann N Y Acad Sci 2013; 1274:140-7. [PMID: 23252909 DOI: 10.1111/j.1749-6632.2012.06782.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Antimuscle-specific kinase (anti-MuSK) myasthenia (AMM) differs from antiacetylcholine receptor myasthenia gravis in exhibiting more focal muscle involvement (neck, shoulder, facial, and bulbar muscles) with wasting of the involved, primarily axial, muscles. AMM is not associated with thymic hyperplasia and responds poorly to anticholinesterase treatment. Animal models of AMM have been induced in rabbits, mice, and rats by immunization with purified xenogeneic MuSK ectodomain, and by passive transfer of large quantities of purified serum IgG from AMM patients into mice. The models have confirmed the pathogenic role of the MuSK antibodies in AMM and have demonstrated the involvement of both the presynaptic and postsynaptic components of the neuromuscular junction. The observations in this human disease and its animal models demonstrate the role of MuSK not only in the formation of this synapse but also in its maintenance.
Collapse
Affiliation(s)
- David P Richman
- Department of Neurology, Center for Neuroscience, University of California, Davis, 95616, USA.
| | | | | | | | | | | | | |
Collapse
|
33
|
Morsch M, Reddel SW, Ghazanfari N, Toyka KV, Phillips WD. Pyridostigmine but not 3,4-diaminopyridine exacerbates ACh receptor loss and myasthenia induced in mice by muscle-specific kinase autoantibody. J Physiol 2013; 591:2747-62. [PMID: 23440963 DOI: 10.1113/jphysiol.2013.251827] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In myasthenia gravis, the neuromuscular junction is impaired by the antibody-mediated loss of postsynaptic acetylcholine receptors (AChRs). Muscle weakness can be improved upon treatment with pyridostigmine, a cholinesterase inhibitor, or with 3,4-diaminopyridine, which increases the release of ACh quanta. The clinical efficacy of pyridostigmine is in doubt for certain forms of myasthenia. Here we formally examined the effects of these compounds in the antibody-induced mouse model of anti-muscle-specific kinase (MuSK) myasthenia gravis. Mice received 14 daily injections of IgG from patients with anti-MuSK myasthenia gravis. This caused reductions in postsynaptic AChR densities and in endplate potential amplitudes. Systemic delivery of pyridostigmine at therapeutically relevant levels from days 7 to 14 exacerbated the anti-MuSK-induced structural alterations and functional impairment at motor endplates in the diaphragm muscle. No such effect of pyridostigmine was found in mice receiving control human IgG. Mice receiving smaller amounts of MuSK autoantibodies did not display overt weakness, but 9 days of pyridostigmine treatment precipitated generalised muscle weakness. In contrast, one week of treatment with 3,4-diaminopyridine enhanced neuromuscular transmission in the diaphragm muscle. Both pyridostigmine and 3,4-diaminopyridine increase ACh in the synaptic cleft yet only pyridostigmine potentiated the anti-MuSK-induced decline in endplate ACh receptor density. These results thus suggest that ongoing pyridostigmine treatment potentiates anti-MuSK-induced AChR loss by prolonging the activity of ACh in the synaptic cleft.
Collapse
Affiliation(s)
- Marco Morsch
- School of Medical Sciences (Physiology) and Bosch Institute, Anderson Stuart Bldg (F13), University of Sydney, NSW 2006, Australia
| | | | | | | | | |
Collapse
|
34
|
Plomp JJ, Huijbers MG, van der Maarel SM, Verschuuren JJ. Pathogenic IgG4 subclass autoantibodies in MuSK myasthenia gravis. Ann N Y Acad Sci 2012; 1275:114-22. [DOI: 10.1111/j.1749-6632.2012.06808.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|