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Naujock M, Stanslowsky N, Bufler S, Naumann M, Reinhardt P, Sterneckert J, Kefalakes E, Kassebaum C, Bursch F, Lojewski X, Storch A, Frickenhaus M, Boeckers TM, Putz S, Demestre M, Liebau S, Klingenstein M, Ludolph AC, Dengler R, Kim KS, Hermann A, Wegner F, Petri S. 4-Aminopyridine Induced Activity Rescues Hypoexcitable Motor Neurons from Amyotrophic Lateral Sclerosis Patient-Derived Induced Pluripotent Stem Cells. Stem Cells 2016; 34:1563-75. [PMID: 26946488 DOI: 10.1002/stem.2354] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/11/2016] [Indexed: 12/13/2022]
Abstract
Despite decades of research on amyotrophic lateral sclerosis (ALS), there is only one approved drug, which minimally extends patient survival. Here, we investigated pathophysiological mechanisms underlying ALS using motor neurons (MNs) differentiated from induced pluripotent stem cells (iPSCs) derived from ALS patients carrying mutations in FUS or SOD1. Patient-derived MNs were less active and excitable compared to healthy controls, due to reduced Na(+) /K(+) ratios in both ALS groups accompanied by elevated potassium channel (FUS) and attenuated sodium channel expression levels (FUS, SOD1). ALS iPSC-derived MNs showed elevated endoplasmic reticulum stress (ER) levels and increased caspase activation. Treatment with the FDA approved drug 4-Aminopyridine (4AP) restored ion-channel imbalances, increased neuronal activity levels and decreased ER stress and caspase activation. This study provides novel pathophysiological data, including a mechanistic explanation for the observed hypoexcitability in patient-derived MNs and a new therapeutic strategy to provide neuroprotection in MNs affected by ALS. Stem Cells 2016;34:1563-1575.
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Affiliation(s)
- Maximilian Naujock
- Department of Neurology, Hannover Medical School, Hannover, Germany.,Molecular Neurobiology Laboratory, McLean Hospital/Harvard Medical School, Belmont, Massachusetts, USA
| | | | - Sebastian Bufler
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Marcel Naumann
- Division for Neurodegenerative Diseases, Department of Neurology, Dresden University of Technology, Dresden, Germany
| | - Peter Reinhardt
- DFG Research Center for Regenerative Therapies (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Jared Sterneckert
- DFG Research Center for Regenerative Therapies (CRTD), Technische Universität Dresden, Dresden, Germany
| | | | - Carola Kassebaum
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Franziska Bursch
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Xenia Lojewski
- Division for Neurodegenerative Diseases, Department of Neurology, Dresden University of Technology, Dresden, Germany
| | - Alexander Storch
- Division for Neurodegenerative Diseases, Department of Neurology, Dresden University of Technology, Dresden, Germany.,DFG Research Center for Regenerative Therapies (CRTD), Technische Universität Dresden, Dresden, Germany.,German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Department of Neurology, University of Rostock, Rostock, Germany
| | | | | | - Stefan Putz
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Maria Demestre
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Stefan Liebau
- Institute of Neuroanatomy, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Moritz Klingenstein
- Institute of Neuroanatomy, Eberhard Karls University Tübingen, Tübingen, Germany
| | | | - Reinhard Dengler
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Kwang-Soo Kim
- Molecular Neurobiology Laboratory, McLean Hospital/Harvard Medical School, Belmont, Massachusetts, USA
| | - Andreas Hermann
- Division for Neurodegenerative Diseases, Department of Neurology, Dresden University of Technology, Dresden, Germany.,German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Florian Wegner
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Hannover, Germany
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Glutamate excitotoxicity inflicts paranodal myelin splitting and retraction. PLoS One 2009; 4:e6705. [PMID: 19693274 PMCID: PMC2725320 DOI: 10.1371/journal.pone.0006705] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 07/20/2009] [Indexed: 11/19/2022] Open
Abstract
Paranodal myelin damage is observed in white matter injury. However the culprit for such damage remains unknown. By coherent anti-Stokes Raman scattering imaging of myelin sheath in fresh tissues with sub-micron resolution, we observed significant paranodal myelin splitting and retraction following glutamate application both ex vivo and in vivo. Multimodal multiphoton imaging further showed that glutamate application broke axo-glial junctions and exposed juxtaparanodal K+ channels, resulting in axonal conduction deficit that was demonstrated by compound action potential measurements. The use of 4-aminopyridine, a broad-spectrum K+ channel blocker, effectively recovered both the amplitude and width of compound action potentials. Using CARS imaging as a quantitative readout of nodal length to diameter ratio, the same kind of paranodal myelin retraction was observed with applications of Ca2+ ionophore A23187. Moreover, exclusion of Ca2+ from the medium or application of calpain inhibitor abolished paranodal myelin retraction during glutamate exposure. Examinations of glutamate receptor agonists and antagonists further showed that the paranodal myelin damage was mediated by NMDA and kainate receptors. These results suggest that an increased level of glutamate in diseased white matter could impair paranodal myelin through receptor-mediated Ca2+ overloading and subsequent calpain activation.
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Judge SIV, Bever CT. Potassium channel blockers in multiple sclerosis: Neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther 2006; 111:224-59. [PMID: 16472864 DOI: 10.1016/j.pharmthera.2005.10.006] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 10/12/2005] [Indexed: 02/07/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by demyelination, with a relative sparing of axons. In MS patients, many neurologic signs and symptoms have been attributed to the underlying conduction deficits. The idea that neurologic function might be improved if conduction could be restored in CNS demyelinated axons led to the testing of potassium (K(+)) channel blockers as a symptomatic treatment. To date, only 2 broad-spectrum K(+) channel blockers, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP), have been tested in MS patients. Although both 4-AP and 3,4-DAP produce clear neurologic benefits, their use has been limited by toxicity. Here we review the current status of basic science and clinical research related to the therapeutic targeting of voltage-gated K(+) channels (K(v)) in MS. By bringing together 3 distinct but interrelated disciplines, we aim to provide perspective on a vast body of work highlighting the lengthy and ongoing process entailed in translating fundamental K(v) channel knowledge into new clinical treatments for patients with MS and other demyelinating diseases. Covered are (1) K(v) channel nomenclature, structure, function, and pharmacology; (2) classic and current experimental morphology and neurophysiology studies of demyelination and conduction deficits; and (3) a comprehensive overview of clinical trials utilizing 4-AP and 3,4-DAP in MS patients.
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Affiliation(s)
- Susan I V Judge
- MS Center of Excellence-East, Research and Neurology Services, VA Maryland Health Care System, USA.
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Abstract
Regioselective palladium-catalyzed amination of 2-chloro-3-iodopyridine followed by a subsequent palladium-catalyzed amination leads to 2,3-diaminopyridines. Treatment with triphosgene affords highly functionalized unsymmetrical imidazo[4,5-b]pyridin-2-ones in just three synthetic steps. A two-step synthesis of pseudosymmetrically disubstituted imidazo[4,5-b]pyridin-2-ones, 1,4-disubstituted pyrido[2,3-b]pyrazinediones, and 1,3-disubstituted thiadiazolo[3,4-b]pyridin-2-ones is also described.
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Affiliation(s)
- Jeffrey T Kuethe
- Department of Process Research, Merck & Co., Inc., P.O. Box 2000, Rahway, New Jersey 07065, USA.
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Abstract
4-Aminopyridine (4-AP or fampridine) is a potassium channel-blocking agent that has been shown to restore conduction in focally demyelinated axons. A sustained-release matrix tablet form of 4-AP (fampridine-SR) is currently undergoing multicenter clinical trials in patients with multiple sclerosis or chronic spinal cord injury. This review describes the pharmacology and mechanisms of action of 4-AP, its pharmacokinetics in human subjects, and the outcomes of clinical trials employing either immediate-release or sustained-release formulations of the drug. The randomized clinical trials that have been completed to date indicate that K+ channel blockade may prove to be a useful strategy for ameliorating central conduction deficits due to demyelination. Diverse neurological gains have been reported for both motor and sensory domains. At the present time, however, the clinical trials have not provided sufficiently robust or definitive evidence of efficacy to gain regulatory approval for the symptomatic management of patients with either multiple sclerosis or spinal cord injury.
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Affiliation(s)
- Keith C Hayes
- Department of Physical Medicine & Rehabilitation, The University of Western Ontario, London, Ontario, Canada.
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Ji J, Li T, Bunnelle WH. Selective Amination of Polyhalopyridines Catalyzed by a Palladium−Xantphos Complex. Org Lett 2003; 5:4611-4. [PMID: 14627396 DOI: 10.1021/ol0357696] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] Amination of 5-bromo-2-chloropyridine (1a) catalyzed by a palladium-Xantphos complex predominately gives 5-amino-2-chloropyridine product 3a in 96% isolated yield and excellent chemoselectivity (3a/4a = 97:3). Amination of 2,5-dibromopyridine (11) under the same conditions exclusively affords 2-amino-5-bromopyridine 4a.
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Affiliation(s)
- Jianguo Ji
- Neuroscience Research, Global Pharmaceutical Research and Development, Department-R47W, AP9A-1, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois 60064, USA.
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Abstract
The objective of this study was to investigate whether the menstrual cycle influences multiple sclerosis (MS) symptoms. Seventy-two normally menstruating women (aged 20-50 years) with MS were interviewed. Of the 60 patients with a relapsing-remitting form of MS (RR-MS), 26 (43%) regularly experienced worsening of their MS symptoms in the period just before, or at the beginning of, the menstruation. Significantly more patients of the group reporting no influence of the premenstrual period on MS symptoms were using an oral contraceptive (p=0.041), suggesting a protective effect. There were 12 patients with the primary chronic progressive form of MS (PCP-MS). None of them experienced an influence of the menstrual cycle on their symptoms. Our results suggest that hormonal changes preceding menstruation may worsen symptoms in a subgroup of women with RR-MS.
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Affiliation(s)
- A Zorgdrager
- Department of Neurology, Academisch Ziekenhuis Groningen, Netherlands
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