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Skov M, Ruijs TQ, Grønnebæk TS, Skals M, Riisager A, Winther JB, Dybdahl KLT, Findsen A, Morgen JJ, Huus N, Broch-Lips M, Nielsen OB, de Cuba CMKE, Heuberger JAAC, de Kam ML, Tannemaat M, Verschuuren JJGM, Knutsen LJS, Kelly NM, Jensen KG, Arnold WD, Burghes AH, Olesen C, Bold J, Petersen TK, Quiroz JA, Hutchison J, Chin ER, Groeneveld GJ, Pedersen TH. The ClC-1 chloride channel inhibitor NMD670 improves skeletal muscle function in rat models and patients with myasthenia gravis. Sci Transl Med 2024; 16:eadk9109. [PMID: 38507469 DOI: 10.1126/scitranslmed.adk9109] [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: 09/19/2023] [Accepted: 02/23/2024] [Indexed: 03/22/2024]
Abstract
Myasthenia gravis (MG) is a neuromuscular disease that results in compromised transmission of electrical signals at the neuromuscular junction (NMJ) from motor neurons to skeletal muscle fibers. As a result, patients with MG have reduced skeletal muscle function and present with symptoms of severe muscle weakness and fatigue. ClC-1 is a skeletal muscle specific chloride (Cl-) ion channel that plays important roles in regulating neuromuscular transmission and muscle fiber excitability during intense exercise. Here, we show that partial inhibition of ClC-1 with an orally bioavailable small molecule (NMD670) can restore muscle function in rat models of MG and in patients with MG. In severely affected MG rats, ClC-1 inhibition enhanced neuromuscular transmission, restored muscle function, and improved mobility after both single and prolonged administrations of NMD670. On this basis, NMD670 was progressed through nonclinical safety pharmacology and toxicology studies, leading to approval for testing in clinical studies. After successfully completing phase 1 single ascending dose in healthy volunteers, NMD670 was tested in patients with MG in a randomized, placebo-controlled, single-dose, three-way crossover clinical trial. The clinical trial evaluated safety, pharmacokinetics, and pharmacodynamics of NMD670 in 12 patients with mild MG. NMD670 had a favorable safety profile and led to clinically relevant improvements in the quantitative myasthenia gravis (QMG) total score. This translational study spanning from single muscle fiber recordings to patients provides proof of mechanism for ClC-1 inhibition as a potential therapeutic approach in MG and supports further development of NMD670.
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Affiliation(s)
- Martin Skov
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Titia Q Ruijs
- Centre for Human Drug Research, 2333 CL Leiden, Netherlands
- Leiden University Medical Centre, 2333 ZA Leiden, Netherlands
| | | | - Marianne Skals
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Anders Riisager
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | | | | | - Anders Findsen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Jeanette J Morgen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Nete Huus
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Martin Broch-Lips
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Ole B Nielsen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
- Department of Biomedicine, Aarhus University, Ole Worms Alle 4, 8000 Aarhus C, Denmark
| | - Catherine M K E de Cuba
- Centre for Human Drug Research, 2333 CL Leiden, Netherlands
- Leiden University Medical Centre, 2333 ZA Leiden, Netherlands
| | | | | | | | | | - Lars J S Knutsen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Nicholas M Kelly
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Klaus G Jensen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - William D Arnold
- NextGen Precision Health, University of Missouri, 1030 Hitt St, Columbia, MO 65212, USA
| | - Arthur H Burghes
- Department of Biological Chemistry and Pharmacology, Ohio State University Wexner Medical Center, 1060 Carmack Road, Columbus, OH 43210, USA
- Department of Neurology, Neuromuscular Division, Ohio State University Wexner Medical Center, 395 W. 12(th) Ave, Columbus, OH 43210, USA
| | - Claus Olesen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
- Department of Biomedicine, Aarhus University, Ole Worms Alle 4, 8000 Aarhus C, Denmark
| | - Jane Bold
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Thomas K Petersen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Jorge A Quiroz
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - John Hutchison
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Eva R Chin
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
| | - Geert J Groeneveld
- Centre for Human Drug Research, 2333 CL Leiden, Netherlands
- Leiden University Medical Centre, 2333 ZA Leiden, Netherlands
| | - Thomas H Pedersen
- NMD Pharma A/S, Palle Juul-Jensens Boulevard 82, 8200 Aarhus N, Denmark
- Department of Biomedicine, Aarhus University, Ole Worms Alle 4, 8000 Aarhus C, Denmark
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Winther JB, Morgen JJ, Skov M, Broch-Lips MG, Nielsen OB, Overgaard K, Pedersen TH. Role of recovery of acetylcholine release in compromised neuromuscular junction function. Neuromuscul Disord 2024; 36:48-59. [PMID: 38359767 DOI: 10.1016/j.nmd.2024.01.007] [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: 09/25/2023] [Revised: 12/17/2023] [Accepted: 01/22/2024] [Indexed: 02/17/2024]
Abstract
Everyday physical activities, such as walking, are enabled by repeated skeletal muscle contractions and require a well-functioning neuromuscular transmission. In myasthenic disorders, activities of daily living are debilitated by a compromised neuromuscular transmission leading to muscle weakness and fatiguability in patients. To enable physical activity, acetylcholine (ACh) is released repeatedly from the motor nerve, however, the role of the nerve terminals' capacity to sustain ACh release to support repetitive contractions under compromised neuromuscular transmission remains unclear. To explore this, we studied synaptic and contractile function during repeated contractions in healthy rat skeletal muscles under conditions of pharmacological induced compromised neuromuscular transmission. Using recordings of endplate potentials, compound muscle action potential (CMAP) and force production in isolated skeletal muscles and living, anesthetized animals, we found that force and CMAP were markedly reduced by even very light activity performed up to 5 s prior to contraction showing that recovery of ACh release was insufficient to maintain synaptic transmission strength. Our results suggest that the timing of depletion and restoration of ACh release may impact clinical signs of weakness and fatigability in patients with impaired neuromuscular transmission and affect the sensitivity of electromyographic recordings in the clinic.
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Affiliation(s)
| | | | - Martin Skov
- NMD Pharma A/S, Palle Juul-Jensens Blvd. 82, 8200 Aarhus N, Denmark
| | | | - Ole Bækgaard Nielsen
- Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus C, Denmark
| | - Kristian Overgaard
- Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus C, Denmark
| | - Thomas Holm Pedersen
- NMD Pharma A/S, Palle Juul-Jensens Blvd. 82, 8200 Aarhus N, Denmark; Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus C, Denmark.
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3
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Liu Y, Lin W. Morphological and functional alterations of neuromuscular synapses in a mouse model of ACTA1 congenital myopathy. Hum Mol Genet 2024; 33:233-244. [PMID: 37883471 PMCID: PMC10800017 DOI: 10.1093/hmg/ddad183] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023] Open
Abstract
Mutations in skeletal muscle α-actin (Acta1) cause myopathies. In a mouse model of congenital myopathy, heterozygous Acta1 (H40Y) knock-in (Acta1+/Ki) mice exhibit features of human nemaline myopathy, including premature lethality, severe muscle weakness, reduced mobility, and the presence of nemaline rods in muscle fibers. In this study, we investigated the impact of Acta1 (H40Y) mutation on the neuromuscular junction (NMJ). We found that the NMJs were markedly fragmented in Acta1+/Ki mice. Electrophysiological analysis revealed a decrease in amplitude but increase in frequency of miniature end-plate potential (mEPP) at the NMJs in Acta1+/Ki mice, compared with those in wild type (Acta1+/+) mice. Evoked end-plate potential (EPP) remained similar at the NMJs in Acta1+/Ki and Acta1+/+ mice, but quantal content was increased at the NMJs in Acta1+/Ki, compared with Acta1+/+ mice, suggesting a homeostatic compensation at the NMJs in Acta1+/Ki mice to maintain normal levels of neurotransmitter release. Furthermore, short-term synaptic plasticity of the NMJs was compromised in Acta1+/Ki mice. Together, these results demonstrate that skeletal Acta1 H40Y mutation, albeit muscle-origin, leads to both morphological and functional defects at the NMJ.
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Affiliation(s)
- Yun Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
| | - Weichun Lin
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
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4
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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: 2.0] [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.
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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.
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5
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Jin Y, Jin W, Sun Q, Li N, Jiang M, Liu Y, Sun L. Role of the chloride channel blocker in the formation of filtering tract scars after glaucoma surgery in rats. Clin Exp Pharmacol Physiol 2023; 50:806-814. [PMID: 37452725 DOI: 10.1111/1440-1681.13803] [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: 11/19/2022] [Revised: 05/09/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023]
Abstract
Filtration surgery is commonly performed for glaucoma treatment to reduce intraocular pressure (IOP); however, scarring of the filtering bleb is the main cause of failure. In this study, we evaluated the effects of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) on scar formation in filtering blebs. A glaucoma filtering surgery model was generated using Sprague-Dawley rats, divided into the control and NPPB groups receiving injections of different NPPB concentrations. The IOP of all rats decreased 1-day post-surgery and gradually increased afterward. However, IOP in rats from the NPPB groups recovered more slowly than that of the control group rats. In addition, the area and survival times of filtering blebs in rats from the NPPB groups were substantially larger and longer than those in the control group. Twenty-eight days after surgery, the protein and mRNA expression of collagen I, fibronectin and α-smooth muscle actin in the filtering area of rats from the NPPB groups were significantly lower than that in the control group rats. Collectively, our study demonstrates that NPPB inhibits filtering bleb scar formation, maintains filtering bleb morphology and prolongs filtering bleb survival time by inhibiting the differentiation of conjunctival fibroblasts and extracellular matrix synthesis.
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Affiliation(s)
- Yujiao Jin
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Weiyi Jin
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Qiushuang Sun
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Nan Li
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Meiling Jiang
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Yinfeng Liu
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
| | - Lixia Sun
- Department of Ophthalmology, The Affiliated Hospital of Yanbian University, Yanji, China
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6
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Brenes O, Pusch M, Morales F. ClC-1 Chloride Channel: Inputs on the Structure-Function Relationship of Myotonia Congenita-Causing Mutations. Biomedicines 2023; 11:2622. [PMID: 37892996 PMCID: PMC10604815 DOI: 10.3390/biomedicines11102622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 10/29/2023] Open
Abstract
Myotonia congenita is a hereditary muscle disease mainly characterized by muscle hyperexcitability, which leads to a sustained burst of discharges that correlates with the magnitude and duration of involuntary aftercontractions, muscle stiffness, and hypertrophy. Mutations in the chloride voltage-gated channel 1 (CLCN1) gene that encodes the skeletal muscle chloride channel (ClC-1) are responsible for this disease, which is commonly known as myotonic chloride channelopathy. The biophysical properties of the mutated channel have been explored and analyzed through in vitro approaches, providing important clues to the general function/dysfunction of the wild-type and mutated channels. After an exhaustive search for CLCN1 mutations, we report in this review more than 350 different mutations identified in the literature. We start discussing the physiological role of the ClC-1 channel in skeletal muscle functioning. Then, using the reported functional effects of the naturally occurring mutations, we describe the biophysical and structural characteristics of the ClC-1 channel to update the knowledge of the function of each of the ClC-1 helices, and finally, we attempt to point out some patterns regarding the effects of mutations in the different helices and loops of the protein.
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Affiliation(s)
- Oscar Brenes
- Departamento de Fisiología, Escuela de Medicina, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
- Centro de Investigación en Neurociencias (CIN), Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, San José 11501-2060, Costa Rica
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7
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Saito A, Matsui S, Chino A, Sato S, Takeshita N. Discovery and pharmacological characterization of novel positive allosteric modulators acting on skeletal muscle-type nicotinic acetylcholine receptors. Biochem Biophys Res Commun 2023; 668:27-34. [PMID: 37235916 DOI: 10.1016/j.bbrc.2023.04.103] [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: 04/11/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023]
Abstract
Skeletal muscle-type nicotinic acetylcholine receptors (m-nAChRs) are ligand-gated ion channels that open after activation by ACh and whose signals cause muscle contraction. Defects in neurotransmission are reported in disorders such as myasthenia gravis (MG) and congenital myasthenia syndromes (CMS). Although treatments for these disorders exist, therapies which significantly increase muscle strength have yet to be reported. Positive allosteric modulators (PAMs), which promote ACh signaling through AChRs, are expected to be promising therapeutic agents. In this study, we identified an m-nAChR PAM called AS3513678 by high-throughput screening using human myotube cells and modified it to obtain novel compounds (AS3566987 and AS3580239) that showed even stronger PAM activity. AS3580239 caused a leftward shift in the ACh concentration-response curve and was 14.0-fold potent at 10 μM compared with vehicle. Next, we examined the effect of AS3580239 on electrically-induced isometric contraction of the extensor digitorum longus (EDL) muscle in wild-type (WT) and MG model rats. AS3580239 enhanced EDL muscle contraction in both WT and MG model rats at 30 μM. These data suggest that AS3580239 improved neurotransmission and enhanced muscle strength. Thus, m-nAChR PAMs may be a useful treatment for neuromuscular diseases.
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Affiliation(s)
- Asako Saito
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.
| | - Shigeo Matsui
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Ayaka Chino
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Shota Sato
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Nobuaki Takeshita
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
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8
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Arnold WD, Clark BC. Neuromuscular junction transmission failure in aging and sarcopenia: The nexus of the neurological and muscular systems. Ageing Res Rev 2023; 89:101966. [PMID: 37270145 PMCID: PMC10847753 DOI: 10.1016/j.arr.2023.101966] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/05/2023] [Accepted: 05/29/2023] [Indexed: 06/05/2023]
Abstract
Sarcopenia, or age-related decline in muscle form and function, exerts high personal, societal, and economic burdens when untreated. Integrity and function of the neuromuscular junction (NMJ), as the nexus between the nervous and muscular systems, is critical for input and dependable neural control of muscle force generation. As such, the NMJ has long been a site of keen interest in the context of skeletal muscle function deficits during aging and in the context of sarcopenia. Historically, changes of NMJ morphology during aging have been investigated extensively but primarily in aged rodent models. Aged rodents have consistently shown features of NMJ endplate fragmentation and denervation. Yet, the presence of NMJ changes in older humans remains controversial, and conflicting findings have been reported. This review article describes the physiological processes involved in NMJ transmission, discusses the evidence that supports NMJ transmission failure as a possible contributor to sarcopenia, and speculates on the potential of targeting these defects for therapeutic development. The technical approaches that are available for assessment of NMJ transmission, whether each approach has been applied in the context of aging and sarcopenia, and the associated findings are summarized. Like morphological studies, age-related NMJ transmission deficits have primarily been studied in rodents. In preclinical studies, isolated synaptic electrophysiology recordings of endplate currents or potentials have been mostly used, and paradoxically, have shown enhancement, rather than failure, with aging. Yet, in vivo assessment of single muscle fiber action potential generation using single fiber electromyography and nerve-stimulated muscle force measurements show evidence of NMJ failure in aged mice and rats. Together these findings suggest that endplate response enhancement may be a compensatory response to post-synaptic mechanisms of NMJ transmission failure in aged rodents. Possible, but underexplored, mechanisms of this failure are discussed including the simplification of post-synaptic folding and altered voltage-gated sodium channel clustering or function. In humans, there is limited clinical data that has selectively investigated single synaptic function in the context of aging. If sarcopenic older adults turn out to exhibit notable impairments in NMJ transmission (this has yet to be examined but based on available evidence appears to be plausible) then these NMJ transmission defects present a well-defined biological mechanism and offer a well-defined pathway for clinical implementation. Investigation of small molecules that are currently available clinically or being testing clinically in other disorders may provide a rapid route for development of interventions for older adults impacted by sarcopenia.
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Affiliation(s)
- W David Arnold
- NextGen Precision Health, University of Missouri System, Columbia, MO, USA; Department of Physical Medicine and Rehabilitation University of Missouri, Columbia, MO, USA.
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI) Ohio University, Athens, OH, USA; Department of Biomedical Sciences, Ohio University, Athens, OH, USA.
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9
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Kirschner KM. Open research data - Expectations and limitations. Acta Physiol (Oxf) 2022; 236:e13900. [PMID: 36269606 DOI: 10.1111/apha.13900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 01/29/2023]
Affiliation(s)
- Karin M Kirschner
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Translational Physiology, Berlin, Germany
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10
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Novel treatment strategies for acetylcholine receptor antibody-positive myasthenia gravis and related disorders. Autoimmun Rev 2022; 21:103104. [PMID: 35452851 DOI: 10.1016/j.autrev.2022.103104] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/18/2022] [Indexed: 11/21/2022]
Abstract
The presence of autoantibodies directed against the muscle nicotinic acetylcholine receptor (AChR) is the most common cause of myasthenia gravis (MG). These antibodies damage the postsynaptic membrane of the neuromuscular junction and cause muscle weakness by depleting AChRs and thus impairing synaptic transmission. As one of the best-characterized antibody-mediated autoimmune diseases, AChR-MG has often served as a reference model for other autoimmune disorders. Classical pharmacological treatments, including broad-spectrum immunosuppressive drugs, are effective in many patients. However, complete remission cannot be achieved in all patients, and 10% of patients do not respond to currently used therapies. This may be attributed to production of autoantibodies by long-lived plasma cells which are resistant to conventional immunosuppressive drugs. Hence, novel therapies specifically targeting plasma cells might be a suitable therapeutic approach for selected patients. Additionally, in order to reduce side effects of broad-spectrum immunosuppression, targeted immunotherapies and symptomatic treatments will be required. This review presents established therapies as well as novel therapeutic approaches for MG and related conditions, with a focus on AChR-MG.
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11
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Kouyoumdzian NM, Kim G, Rudi MJ, Rukavina Mikusic NL, Fernández BE, Choi MR. Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion. Pflugers Arch 2021; 474:155-176. [PMID: 34966955 DOI: 10.1007/s00424-021-02649-5] [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: 10/17/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 02/06/2023]
Abstract
The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.
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Affiliation(s)
- Nicolás Martín Kouyoumdzian
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.
| | - Gabriel Kim
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Julieta Rudi
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Natalia Lucía Rukavina Mikusic
- Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Marcelo Roberto Choi
- Universidad de Buenos Aires, CONICET, Instituto Alberto C. Taquini de Investigaciones en Medicina Traslacional (IATIMET), Buenos Aires, Argentina.,Facultad de Farmacia Y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Anatomía e Histología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto Universitario de Ciencias de La Salud, Fundación H.A. Barceló, Buenos Aires, Argentina
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12
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Stephenson DG. ClC-1 Cl - channels as modulators of signal transmission at neuromuscular junction. Acta Physiol (Oxf) 2021; 233:e13718. [PMID: 34273251 DOI: 10.1111/apha.13718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- D. George Stephenson
- Department of Physiology, Anatomy and Microbiology School of Life Science La Trobe University Bundoora VIC Australia
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