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Bhatia IPS, Hasvi J, Nazneen PS, Rajan A. Hypokalemic Periodic Paralysis: A Rare Case of a Descending Flaccid Paralysis. Cureus 2024; 16:e55981. [PMID: 38606215 PMCID: PMC11007483 DOI: 10.7759/cureus.55981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/04/2024] [Indexed: 04/13/2024] Open
Abstract
Hypokalemic periodic paralysis (HPP) is an uncommon condition resulting from channelopathy, impacting skeletal muscles. It is distinguished by episodes of sudden and temporary muscle weakness alongside low potassium levels. The normalization of potassium resolves the associated paralysis. Most of these cases are hereditary. Few cases are acquired and are associated with an etiology related to endocrine disorders (e.g., thyrotoxicosis, hyperaldosteronism, and hypercortisolism). It is characterized by acute flaccid paralysis, usually of the ascending type, affecting the proximal region more than the distal region. Herein, we report the case of a 29-year-old male who instead of the ascending type presented with descending-type acute flaccid paralysis. Potassium level at presentation was 1.7 mEq/L. The patient was managed with parenteral and oral potassium supplementation, after which the weakness was completely resolved.
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Affiliation(s)
| | - Jayaraj Hasvi
- Department of Internal Medicine, 167 Military Hospital, Pathankot, IND
| | | | - Amit Rajan
- Department of Lab Sciences and Pathology, 167 Military Hospital, Pathankot, IND
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Bisciglia M, Kadhim H, Lecomte S, Vandernoot I, Desmyter L, Remiche G. Early-Onset Autosomal Dominant Myopathy with Vacuolated Fibers and Tubular Aggregates but No Periodic Paralysis, in a Patient with the c.1583G>A (p.R528H) mutation in the CACNA1S Gene. J Neuromuscul Dis 2024; 11:871-875. [PMID: 38788083 PMCID: PMC11307083 DOI: 10.3233/jnd-230020] [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] [Accepted: 02/13/2024] [Indexed: 05/26/2024]
Abstract
Dominant mutations in CACNA1S gene mainly causes hypokalemic periodic paralysis (PP)(hypoPP). A 68-year-old male proband developed a progressive proximal weakness from the age of 35. Muscle biopsy showed atrophic fibers with vacuoles containing tubular aggregates. Exome sequencing revealed a heterozygous p.R528H (c.1583G>A) mutation in the CACNA1S gene. CACNA1S-related HypoPP evolving to persistent myopathy in late adulthood is a well-known clinical condition. However, isolated progressive myopathy (without PP) was only exceptionally reported and never with an early onset. Reporting a case of early onset CACNA1S-related myopathy in a patient with no HypoPP we intend to alert clinicians to consider it in the differential diagnosis of younger adult-onset myopathies especially when featuring vacuolar changes.
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Affiliation(s)
- Michela Bisciglia
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Hazim Kadhim
- Neuropathology Unit and Reference Center for Neuromuscular Pathology, Department of Pathology, CHU Brugmann, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Sophie Lecomte
- Neuropathology Unit and Reference Center for Neuromuscular Pathology, Department of Pathology, CHU Brugmann, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Isabelle Vandernoot
- Department of Genetics, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Laurence Desmyter
- Department of Genetics, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Gauthier Remiche
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
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3
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Holm-Yildiz S, Krag T, Witting N, Pedersen BS, Dysgaard T, Sloth L, Pedersen J, Kjær R, Kannuberg L, Dahlqvist J, de Stricker Borch J, Solheim T, Fornander F, Eisum AS, Vissing J. Hypokalemic periodic paralysis: a 3-year follow-up study. J Neurol 2023; 270:6057-6063. [PMID: 37656291 PMCID: PMC10632268 DOI: 10.1007/s00415-023-11964-z] [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: 05/22/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND AND OBJECTIVES Primary hypokalemic periodic paralysis (HypoPP) is an inherited channelopathy most commonly caused by mutations in CACNA1S. HypoPP can present with different phenotypes: periodic paralysis (PP), permanent muscle weakness (PW), and mixed weakness (MW) with both periodic and permanent weakness. Little is known about the natural history of HypoPP. METHODS In this 3-year follow-up study, we used the MRC scale for manual muscle strength testing and whole-body muscle MRI (Mercuri score) to assess disease progression in individuals with HypoPP-causing mutations in CACNA1S. RESULTS We included 25 men (mean age 43 years, range 18-76 years) and 12 women (mean age 42 years, range 18-76 years). Two participants were asymptomatic, 21 had PP, 12 MW, and two PW. The median number of months between baseline and follow-up was 42 (range 26-52). Muscle strength declined in 11 patients during follow-up. Four of the patients with a decline in muscle strength had no attacks of paralysis during follow-up, and two of these patients had never had attacks of paralysis. Fat replacement of muscles increased in 27 patients during follow-up. Eight of the patients with increased fat replacement had no attacks of paralysis during follow-up, and two of these patients had never had attacks of paralysis. DISCUSSION The study demonstrates that HypoPP can be a progressive myopathy in both patients with and without attacks of paralysis.
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Affiliation(s)
- Sonja Holm-Yildiz
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.
| | - Thomas Krag
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Nanna Witting
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Britt Stævnsbo Pedersen
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Tina Dysgaard
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Louise Sloth
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Jonas Pedersen
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Rebecca Kjær
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Linda Kannuberg
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Julia Dahlqvist
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Josefine de Stricker Borch
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Tuva Solheim
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Freja Fornander
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - Anne-Sofie Eisum
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark
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Arcos-Hernández C, Nishigaki T. Ion currents through the voltage sensor domain of distinct families of proteins. J Biol Phys 2023; 49:393-413. [PMID: 37851173 PMCID: PMC10651576 DOI: 10.1007/s10867-023-09645-z] [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: 04/28/2023] [Accepted: 09/11/2023] [Indexed: 10/19/2023] Open
Abstract
The membrane potential of a cell (Vm) regulates several physiological processes. The voltage sensor domain (VSD) is a region that confers voltage sensitivity to different types of transmembrane proteins such as the following: voltage-gated ion channels, the voltage-sensing phosphatase (Ci-VSP), and the sperm-specific Na+/H+ exchanger (sNHE). VSDs contain four transmembrane segments (S1-S4) and several positively charged amino acids in S4, which are essential for the voltage sensitivity of the protein. Generally, in response to changes of the Vm, the positive residues of S4 displace along the plasma membrane without generating ionic currents through this domain. However, some native (e.g., Hv1 channel) and mutants of VSDs produce ionic currents. These gating pore currents are usually observed in VSDs that lack one or more of the conserved positively charged amino acids in S4. The gating pore currents can also be induced by the isolation of a VSD from the rest of the protein domains. In this review, we summarize gating pore currents from all families of proteins with VSDs with classification into three cases: (1) pathological, (2) physiological, and (3) artificial currents. We reinforce the model in which the position of S4 that lacks the positively charged amino acid determines the voltage dependency of the gating pore current of all VSDs independent of protein families.
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Affiliation(s)
- César Arcos-Hernández
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
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5
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Takács R, Kovács P, Ebeid RA, Almássy J, Fodor J, Ducza L, Barrett-Jolley R, Lewis R, Matta C. Ca2+-Activated K+ Channels in Progenitor Cells of Musculoskeletal Tissues: A Narrative Review. Int J Mol Sci 2023; 24:ijms24076796. [PMID: 37047767 PMCID: PMC10095002 DOI: 10.3390/ijms24076796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/01/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023] Open
Abstract
Musculoskeletal disorders represent one of the main causes of disability worldwide, and their prevalence is predicted to increase in the coming decades. Stem cell therapy may be a promising option for the treatment of some of the musculoskeletal diseases. Although significant progress has been made in musculoskeletal stem cell research, osteoarthritis, the most-common musculoskeletal disorder, still lacks curative treatment. To fine-tune stem-cell-based therapy, it is necessary to focus on the underlying biological mechanisms. Ion channels and the bioelectric signals they generate control the proliferation, differentiation, and migration of musculoskeletal progenitor cells. Calcium- and voltage-activated potassium (KCa) channels are key players in cell physiology in cells of the musculoskeletal system. This review article focused on the big conductance (BK) KCa channels. The regulatory function of BK channels requires interactions with diverse sets of proteins that have different functions in tissue-resident stem cells. In this narrative review article, we discuss the main ion channels of musculoskeletal stem cells, with a focus on calcium-dependent potassium channels, especially on the large conductance BK channel. We review their expression and function in progenitor cell proliferation, differentiation, and migration and highlight gaps in current knowledge on their involvement in musculoskeletal diseases.
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Affiliation(s)
- Roland Takács
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Patrik Kovács
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Rana Abdelsattar Ebeid
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - János Almássy
- Department of Physiology, Faculty of Medicine, Semmelweis University, H-1428 Budapest, Hungary
| | - János Fodor
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - László Ducza
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Richard Barrett-Jolley
- Department of Musculoskeletal Biology, Faculty of Health and Life Sciences, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
| | - Rebecca Lewis
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Csaba Matta
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [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] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Hati A, Chakraborty U, Chandra A, Biswas P. Hypokalaemia with Guillain-Barré syndrome: a diagnostic and therapeutic challenge. BMJ Case Rep 2022; 15:e249473. [PMID: 35760510 PMCID: PMC9237892 DOI: 10.1136/bcr-2022-249473] [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] [Accepted: 06/14/2022] [Indexed: 11/03/2022] Open
Abstract
Acute-onset quadriparesis is not only debilitating and a grave concern for the patient but also perturbs the clinician as it demands early diagnosis and prompt management to prevent catastrophic outcome due to respiratory failure. Guillain-Barré syndrome (GBS) and hypokalaemia are notorious causes of acute-onset lower motor neuron (LMN) quadriparesis and warrant a rapid evaluation to necessitate early management. However, coexistence of these two entities is extremely rare and may pose a diagnostic and therapeutic challenge and mandates exclusion of either condition to avoid a poor outcome. We hereby report a case of a young woman who presented with an acute-onset LMN quadriparesis, initially found to have significant hypokalaemia with poor response to supplementation and was further evaluated to have an axonal variant of GBS.
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Affiliation(s)
- Arkapravo Hati
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
| | - Uddalak Chakraborty
- Neurology, Institute of Postgraduate Medical Education and Research Bangur Institute of Neurology, Kolkata, India
| | - Atanu Chandra
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
| | - Purbasha Biswas
- Internal Medicine, RG Kar Medical College and Hospital, Kolkata, West Bengal, India
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8
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DiFranco M, Cannon S. Voltage-Dependent Ca 2+ Release Is Impaired in Hypokalemic Periodic Paralysis Caused by Ca V1.1-R528H but not by Na V1.4-R669H. Am J Physiol Cell Physiol 2022; 323:C478-C485. [PMID: 35759432 PMCID: PMC9359662 DOI: 10.1152/ajpcell.00209.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypokalemic periodic paralysis (HypoPP) is a channelopathy of skeletal muscle caused by missense mutations in the voltage sensor domains (usually at an arginine of the S4 segment) of the CaV1.1 calcium channel or of the NaV1.4 sodium channel. The primary clinical manifestation is recurrent attacks of weakness, resulting from impaired excitability of anomalously depolarized fibers containing leaky mutant channels. While the ictal loss of fiber excitability is sufficient to explain the acute episodes of weakness, a deleterious change in voltage sensor function for CaV1.1 mutant channels may also compromise excitation-contraction coupling (EC-coupling). We used the low-affinity Ca2+ indicator OGN-5 to assess voltage-dependent Ca2+-release as a measure of EC-coupling for our knock-in mutant mouse models of HypoPP. The peak in fibers isolated from CaV1.1-R528H mice was about two-thirds of the amplitude observed in WT mice; whereas in HypoPP fibers from NaV1.4-R669H mice the was indistinguishable from WT. No difference in the voltage dependence of from WT was observed for fibers from either HypoPP mouse model. Because late-onset permanent muscle weakness is more severe for CaV1.1-associated HypoPP than for NaV1.4, we propose the reduced Ca2+-release for CaV1.1-R528H mutant channels may increase the susceptibility to fixed myopathic weakness. In contrast the episodes of transient weakness are similar for CaV1.1- and NaV1.4-associated HypoPP, consistent with the notion that acute attacks of weakness are primarily caused by leaky channels and are not a consequence of reduced Ca2+-release.
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Affiliation(s)
- Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA United States
| | - Steve Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA United States.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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9
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Villar-Quiles RN, Sternberg D, Tredez G, Beatriz Romero N, Evangelista T, Lafôret P, Cintas P, Sole G, Sacconi S, Bendahhou S, Franques J, Cances C, Noury JB, Delmont E, Blondy P, Perrin L, Hezode M, Fournier E, Fontaine B, Stojkovic T, Vicart S. Phenotypical variability and atypical presentations in a French cohort of Andersen-Tawil syndrome. Eur J Neurol 2022; 29:2398-2411. [PMID: 35460302 DOI: 10.1111/ene.15369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/31/2022] [Accepted: 04/18/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND AND PURPOSE Andersen-Tawil syndrome (ATS) is a skeletal muscle channelopathy caused by KCNJ2 mutations, characterized by a clinical triad of periodic paralysis, cardiac arrhythmias and dysmorphism. The muscle phenotype, particularly the atypical forms with prominent permanent weakness or predominantly painful symptoms, remains incompletely characterized. METHODS A retrospective clinical, histological, electroneuromyography (ENMG) and genetic analysis of molecularly confirmed ATS patients, diagnosed and followed up at neuromuscular reference centers in France, was conducted. RESULTS Thirty-five patients from 27 unrelated families carrying 17 different missense KCNJ2 mutations (four novel mutations) and a heterozygous KCNJ2 duplication are reported. The typical triad was observed in 42.9% of patients. Cardiac abnormalities were observed in 65.7%: 56.5% asymptomatic and 39.1% requiring antiarrhythmic drugs. 71.4% of patients exhibited dysmorphic features. Muscle symptoms were reported in 85.7%, amongst whom 13.3% had no cardiopathy and 33.3% no dysmorphic features. Periodic paralysis was present in 80% and was significantly more frequent in men. Common triggers were exercise, immobility and carbohydrate-rich diet. Ictal serum potassium concentrations were low in 53.6%. Of the 35 patients, 45.7% had permanent weakness affecting proximal muscles, which was mild and stable or slowly progressive over several decades. Four patients presented with exercise-induced pain and myalgia attacks. Diagnostic delay was 14.4 ± 9.5 years. ENMG long-exercise test performed in 25 patients (71.4%) showed in all a decremental response up to 40%. Muscle biopsy performed in 12 patients revealed tubular aggregates in six patients (associated in two of them with vacuolar lesions), dystrophic features in one patient and non-specific myopathic features in one patient; it was normal in four patients. DISCUSSION Recognition of atypical features (exercise-induced pain or myalgia and permanent weakness) along with any of the elements of the triad should arouse suspicion. The ENMG long-exercise test has a high diagnostic yield and should be performed. Early diagnosis is of utmost importance to improve disease prognosis.
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Affiliation(s)
- Rocio Nur Villar-Quiles
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.,Institute of Myology, Centre de Recherche en Myologie, UMRS974, Sorbonne Université - INSERM, Paris, France
| | - Damien Sternberg
- Reference Center for Muscle Channelopathies, Service de Biochimie et Centre de Génétique, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Grégoire Tredez
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Norma Beatriz Romero
- Institute of Myology, Centre de Recherche en Myologie, UMRS974, Sorbonne Université - INSERM, Paris, France.,Neuromuscular Morphology Unit, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Teresinha Evangelista
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.,Institute of Myology, Centre de Recherche en Myologie, UMRS974, Sorbonne Université - INSERM, Paris, France.,Neuromuscular Morphology Unit, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Pascal Lafôret
- Reference Center for Neuromuscular Disorders, APHP, Raymond-Poincaré Hospital, Paris, France
| | - Pascal Cintas
- Neurology Department, Pierre-Paul Riquet Hospital, CHU Toulouse, Toulouse, France
| | - Guilhem Sole
- Reference Centre for Neuromuscular Disorders, Pellegrin Hospital CHU Bordeaux, Bordeaux, France
| | - Sabrina Sacconi
- Neuromuscular Diseases and ALS Specialized Center, University of Nice-Sophia Antipolis, Nice, France
| | - Said Bendahhou
- UMR7370 CNRS, LP2M, Labex ICST, Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France
| | - Jérôme Franques
- Assistance Publique-Hôpitaux de Marseille, Department of Neurology and Neuromuscular Diseases, La Timone Hospital, Marseille, France
| | - Claude Cances
- AOC (Atlantique-Occitanie-Caraïbe) Reference Centre for Neuromuscular Disorders, Neuropediatric Department, Toulouse University Hospital, Toulouse, France
| | - J B Noury
- Neurology Department, Neuromuscular Center, CHRU Cavale Blanche, Brest, France
| | - Emilien Delmont
- Department of Neurology, University Hospital Timone, Marseille, France
| | - Patricia Blondy
- Reference Center for Muscle Channelopathies, Service de Biochimie et Centre de Génétique, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Laurence Perrin
- Pediatrics Department, APHP, Robert-Débré Hospital, Paris, France
| | - Marianne Hezode
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Emmanuel Fournier
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France
| | - Bertrand Fontaine
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.,Institute of Myology, Centre de Recherche en Myologie, UMRS974, Sorbonne Université - INSERM, Paris, France.,Reference Center for Muscle Channelopathies, APHP, Institut de Myologie, Pitié-Salpêtrière Hospital, Paris, France
| | - Tanya Stojkovic
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.,Institute of Myology, Centre de Recherche en Myologie, UMRS974, Sorbonne Université - INSERM, Paris, France
| | - Savine Vicart
- Reference Center for Neuromuscular Disorders, APHP, Institute of Myology, Pitié-Salpêtrière Hospital, Paris, France.,Reference Center for Muscle Channelopathies, APHP, Institut de Myologie, Pitié-Salpêtrière Hospital, Paris, France
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10
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Benítez-Alonso EO, López-Hernández JC, Galnares-Olalde JA, Alcalá RE, Vargas-Cañas ES. Short-Communication: Variable Expression of Clinical Symptoms and an Unexpected Finding of Vacuolar Myopathy Related to a Pathogenic Variant in the CACNA1S Gene in a Previous Case Report. Cureus 2022; 14:e23760. [PMID: 35509735 PMCID: PMC9060183 DOI: 10.7759/cureus.23760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2022] [Indexed: 11/05/2022] Open
Abstract
Several clinical phenotypes have been described related to the CACNA1S gene (calcium channel voltage-dependent L-type alpha-1S subunit), such as autosomal dominant hypokalemic periodic paralysis 1 and autosomal dominant malignant hyperthermia susceptibility and are associated with autosomal dominant and recessive congenital myopathy. Recently, an interesting case of a 58-year-old male patient was published describing an unusual clinical presentation of hypokalemic periodic paralysis where a late-onset limb-girdle myopathy had developed 41 years after paralysis occurred when the patient was 11 years old. Muscle biopsy results were consistent with myopathic changes and revealed the presence of vacuoles, without inflammatory reaction. Later, molecular analysis revealed a pathogenic variant c.3716G>A (p.Arg1239His) in exon 30 of the CACNA1S gene. This technical report provides an extension of the molecular findings and evaluates the clinical and histopathological relationship previously published regarding this case.
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11
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Treatment and Management of Disorders of Neuromuscular Hyperexcitability and Periodic Paralysis. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Wu F, Quinonez M, Cannon SC. Gating pore currents occur in CaV1.1 domain III mutants associated with HypoPP. J Gen Physiol 2021; 153:212609. [PMID: 34463712 PMCID: PMC8563280 DOI: 10.1085/jgp.202112946] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/12/2021] [Indexed: 11/20/2022] Open
Abstract
Mutations in the voltage sensor domain (VSD) of CaV1.1, the α1S subunit of the L-type calcium channel in skeletal muscle, are an established cause of hypokalemic periodic paralysis (HypoPP). Of the 10 reported mutations, 9 are missense substitutions of outer arginine residues (R1 or R2) in the S4 transmembrane segments of the homologous domain II, III (DIII), or IV. The prevailing view is that R/X mutations create an anomalous ion conduction pathway in the VSD, and this so-called gating pore current is the basis for paradoxical depolarization of the resting potential and weakness in low potassium for HypoPP fibers. Gating pore currents have been observed for four of the five CaV1.1 HypoPP mutant channels studied to date, the one exception being the charge-conserving R897K in R1 of DIII. We tested whether gating pore currents are detectable for the other three HypoPP CaV1.1 mutations in DIII. For the less conserved R1 mutation, R897S, gating pore currents with exceptionally large amplitude were observed, correlating with the severe clinical phenotype of these patients. At the R2 residue, gating pore currents were detected for R900G but not R900S. These findings show that gating pore currents may occur with missense mutations at R1 or R2 in S4 of DIII and that the magnitude of this anomalous inward current is mutation specific.
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Affiliation(s)
- Fenfen Wu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
| | - Marbella Quinonez
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
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13
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Nicole S, Lory P. New Challenges Resulting From the Loss of Function of Na v1.4 in Neuromuscular Diseases. Front Pharmacol 2021; 12:751095. [PMID: 34671263 PMCID: PMC8521073 DOI: 10.3389/fphar.2021.751095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
The voltage-gated sodium channel Nav1.4 is a major actor in the excitability of skeletal myofibers, driving the muscle force in response to nerve stimulation. Supporting further this key role, mutations in SCN4A, the gene encoding the pore-forming α subunit of Nav1.4, are responsible for a clinical spectrum of human diseases ranging from muscle stiffness (sodium channel myotonia, SCM) to muscle weakness. For years, only dominantly-inherited diseases resulting from Nav1.4 gain of function (GoF) were known, i.e., non-dystrophic myotonia (delayed muscle relaxation due to myofiber hyperexcitability), paramyotonia congenita and hyperkalemic or hypokalemic periodic paralyses (episodic flaccid muscle weakness due to transient myofiber hypoexcitability). These last 5 years, SCN4A mutations inducing Nav1.4 loss of function (LoF) were identified as the cause of dominantly and recessively-inherited disorders with muscle weakness: periodic paralyses with hypokalemic attacks, congenital myasthenic syndromes and congenital myopathies. We propose to name this clinical spectrum sodium channel weakness (SCW) as the mirror of SCM. Nav1.4 LoF as a cause of permanent muscle weakness was quite unexpected as the Na+ current density in the sarcolemma is large, securing the ability to generate and propagate muscle action potentials. The properties of SCN4A LoF mutations are well documented at the channel level in cellular electrophysiological studies However, much less is known about the functional consequences of Nav1.4 LoF in skeletal myofibers with no available pertinent cell or animal models. Regarding the therapeutic issues for Nav1.4 channelopathies, former efforts were aimed at developing subtype-selective Nav channel antagonists to block myofiber hyperexcitability. Non-selective, Nav channel blockers are clinically efficient in SCM and paramyotonia congenita, whereas patient education and carbonic anhydrase inhibitors are helpful to prevent attacks in periodic paralyses. Developing therapeutic tools able to counteract Nav1.4 LoF in skeletal muscles is then a new challenge in the field of Nav channelopathies. Here, we review the current knowledge regarding Nav1.4 LoF and discuss the possible therapeutic strategies to be developed in order to improve muscle force in SCW.
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Affiliation(s)
- Sophie Nicole
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
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14
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Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
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Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
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15
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Holm-Yildiz S, Krag T, Witting N, Duno M, Soerensen T, Vissing J. Vacuoles, Often Containing Glycogen, Are a Consistent Finding in Hypokalemic Periodic Paralysis. J Neuropathol Exp Neurol 2021; 79:1127-1129. [PMID: 32954434 DOI: 10.1093/jnen/nlaa063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/22/2020] [Accepted: 06/05/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Thomas Krag
- Copenhagen Neuromuscular Center, Department of Neurology
| | - Nanna Witting
- Copenhagen Neuromuscular Center, Department of Neurology
| | | | - Troels Soerensen
- Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; and Neurology Practice, Herlev, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology
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16
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Weber MA, Nagel AM, Kan HE, Wattjes MP. Quantitative Imaging in Muscle Diseases with Focus on Non-proton MRI and Other Advanced MRI Techniques. Semin Musculoskelet Radiol 2020; 24:402-412. [PMID: 32992368 DOI: 10.1055/s-0040-1712955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The role of neuromuscular imaging in the diagnosis of inherited and acquired muscle diseases has gained clinical relevance. In particular, magnetic resonance imaging (MRI), especially whole-body applications, is increasingly being used for the diagnosis and monitoring of disease progression. In addition, they are considered as a powerful outcome measure in clinical trials. Because many muscle diseases have a distinct muscle involvement pattern, whole-body imaging can be of diagnostic value by identifying this pattern and thus narrowing the differential diagnosis and supporting the clinical diagnosis. In addition, more advanced MRI applications including non-proton MRI, diffusion tensor imaging, perfusion MRI, T2 mapping, and magnetic resonance spectroscopy provide deeper insights into muscle pathophysiology beyond the mere detection of fatty degeneration and/or muscle edema. In this review article, we present and discuss recent data on these quantitative MRI techniques in muscle diseases, with a particular focus on non-proton imaging techniques.
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Affiliation(s)
- Marc-André Weber
- Institute of Diagnostic and Interventional Radiology, Pediatric Radiology and Neuroradiology, University Medical Center Rostock, Rostock, Germany
| | - Armin M Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.,Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hermien E Kan
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Duchenne Center, The Netherlands
| | - Mike P Wattjes
- Department of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany
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17
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Holm-Yildiz S, Witting N, Dahlqvist J, de Stricker Borch J, Solheim T, Fornander F, Eisum AS, Duno M, Soerensen T, Vissing J. Permanent muscle weakness in hypokalemic periodic paralysis. Neurology 2020; 95:e342-e352. [PMID: 32580975 DOI: 10.1212/wnl.0000000000009828] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 01/05/2020] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE To map the phenotypic spectrum in 55 individuals with mutations in CACNA1S known to cause hypokalemic periodic paralysis (HypoPP) using medical history, muscle strength testing, and muscle MRI. METHODS Adults with a mutation in CACNA1S known to cause HypoPP were included. Medical history was obtained. Muscle strength and MRI assessments were performed. RESULTS Fifty-five persons were included. Three patients presented with permanent muscle weakness and never attacks of paralysis. Seventeen patients presented with a mixed phenotype of periodic paralysis and permanent weakness. Thirty-one patients presented with the classical phenotype of periodic attacks of paralysis and no permanent weakness. Four participants were asymptomatic. Different phenotypes were present in 9 of 18 families. All patients with permanent weakness had abnormal replacement of muscle by fat on MRI. In addition, 20 of 35 participants with no permanent weakness had abnormal fat replacement of muscle on MRI. The most severely affected muscles were the paraspinal muscles, psoas, iliacus, the posterior muscles of the thigh and gastrocnemius, and soleus of the calf. Age was associated with permanent weakness and correlated with severity of weakness and fat replacement of muscle on MRI. CONCLUSIONS Our results show that phenotype in individuals with HypoPP-causing mutations in CACNA1S varies from asymptomatic to periodic paralysis with or without permanent muscle weakness or permanent weakness as sole presenting picture. Variable phenotypes are found within families. Muscle MRI reveals fat replacement in patients with no permanent muscle weakness, suggesting a convergence of phenotype towards a fixed myopathy with aging.
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Affiliation(s)
- Sonja Holm-Yildiz
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark.
| | - Nanna Witting
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Julia Dahlqvist
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Josefine de Stricker Borch
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Tuva Solheim
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Freja Fornander
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Anne-Sofie Eisum
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Morten Duno
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - Troels Soerensen
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
| | - John Vissing
- From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark
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18
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Mijares A, Espinosa R, Adams J, Lopez JR. Increases in [IP3]i aggravates diastolic [Ca2+] and contractile dysfunction in Chagas' human cardiomyocytes. PLoS Negl Trop Dis 2020; 14:e0008162. [PMID: 32275663 PMCID: PMC7176279 DOI: 10.1371/journal.pntd.0008162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/22/2020] [Accepted: 02/21/2020] [Indexed: 11/18/2022] Open
Abstract
Chagas cardiomyopathy is the most severe manifestation of human Chagas disease and represents the major cause of morbidity and mortality in Latin America. We previously demonstrated diastolic Ca2+ alterations in cardiomyocytes isolated from Chagas' patients to different degrees of cardiac dysfunction. In addition, we have found a significant elevation of diastolic [Na+]d in Chagas' cardiomyocytes (FCII>FCI) that was greater than control. Exposure of cardiomyocytes to agents that enhance inositol 1,4,5 trisphosphate (IP3) generation or concentration like endothelin (ET-1) or bradykinin (BK), or membrane-permeant myoinositol 1,4,5-trisphosphate hexakis(butyryloxy-methyl) esters (IP3BM) caused an elevation in diastolic [Ca2+] ([Ca2+]d) that was always greater in cardiomyocytes from Chagas' than non- Chagas' subjects, and the magnitude of the [Ca2+]d elevation in Chagas' cardiomyocytes was related to the degree of cardiac dysfunction. Incubation with xestospongin-C (Xest-C), a membrane-permeable selective blocker of the IP3 receptors (IP3Rs), significantly reduced [Ca2+]d in Chagas' cardiomyocytes but did not have a significant effect on non-Chagas' cells. The effects of ET-1, BK, and IP3BM on [Ca2+]d were not modified by the removal of extracellular [Ca2+]e. Furthermore, cardiomyocytes from Chagas' patients had a significant decrease in the sarcoplasmic reticulum (SR) Ca2+content compared to control (Control>FCI>FCII), a higher intracellular IP3 concentration ([IP3]i) and markedly depressed contractile properties compared to control cardiomyocytes. These results provide additional and convincing support about the implications of IP3 in the pathogenesis of Chagas cardiomyopathy in patients at different stages of chronic infection. Additionally, these findings open the door for novel therapeutic strategies oriented to improve cardiac function and quality of life of individuals suffering from chronic Chagas cardiomyopathy (CC).
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Affiliation(s)
- Alfredo Mijares
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Raúl Espinosa
- Departamento de Cardiología, Hospital Miguel Pérez Carreño, Instituto venezolano de los Seguros Sociales, Caracas, Venezuela
| | - José Adams
- Division of Neonatology, Mount Sinai, Medical Center, Miami, FL, United States of America
| | - José R. Lopez
- Department of Research, Mount Sinai, Medical Center, Miami, FL, United States of America
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19
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Flucher BE. Skeletal muscle Ca V1.1 channelopathies. Pflugers Arch 2020; 472:739-754. [PMID: 32222817 PMCID: PMC7351834 DOI: 10.1007/s00424-020-02368-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
CaV1.1 is specifically expressed in skeletal muscle where it functions as voltage sensor of skeletal muscle excitation-contraction (EC) coupling independently of its functions as L-type calcium channel. Consequently, all known CaV1.1-related diseases are muscle diseases and the molecular and cellular disease mechanisms relate to the dual functions of CaV1.1 in this tissue. To date, four types of muscle diseases are known that can be linked to mutations in the CACNA1S gene or to splicing defects. These are hypo- and normokalemic periodic paralysis, malignant hyperthermia susceptibility, CaV1.1-related myopathies, and myotonic dystrophy type 1. In addition, the CaV1.1 function in EC coupling is perturbed in Native American myopathy, arising from mutations in the CaV1.1-associated protein STAC3. Here, we first address general considerations concerning the possible roles of CaV1.1 in disease and then discuss the state of the art regarding the pathophysiology of the CaV1.1-related skeletal muscle diseases with an emphasis on molecular disease mechanisms.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Biophysics, Medical University Innsbruck, Schöpfstraße 41, A6020, Innsbruck, Austria.
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20
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In vivo assessment of interictal sarcolemmal membrane properties in hypokalaemic and hyperkalaemic periodic paralysis. Clin Neurophysiol 2020; 131:816-827. [PMID: 32066100 DOI: 10.1016/j.clinph.2019.12.414] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/26/2019] [Accepted: 12/10/2019] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Hypokalaemic periodic paralysis (HypoPP) is caused by mutations of Cav1.1, and Nav1.4 which result in an aberrant gating pore current. Hyperkalaemic periodic paralysis (HyperPP) is due to a gain-of-function mutation of the main alpha pore of Nav1.4. This study used muscle velocity recovery cycles (MVRCs) to investigate changes in interictal muscle membrane properties in vivo. METHODS MVRCs and responses to trains of stimuli were recorded in tibialis anterior and compared in patients with HyperPP(n = 7), HypoPP (n = 10), and normal controls (n = 26). RESULTS Muscle relative refractory period was increased, and early supernormality reduced in HypoPP, consistent with depolarisation of the interictal resting membrane potential. In HyperPP the mean supernormality and residual supernormality to multiple conditioning stimuli were increased, consistent with increased inward sodium current and delayed repolarisation, predisposing to spontaneous myotonic discharges. CONCLUSIONS The in vivo findings suggest the interictal resting membrane potential is depolarized in HypoPP, and mostly normal in HyperPP. The MVRC findings in HyperPP are consistent with presence of a window current, previously proposed on the basis of in vitro expression studies. Although clinically similar, HyperPP was electrophysiologically distinct from paramyotonia congenita. SIGNIFICANCE MVRCs provide important in vivo data that complements expression studies of ion channel mutations.
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21
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Toward Decoding Bioelectric Events in Xenopus Embryogenesis: New Methodology for Tracking Interplay Between Calcium and Resting Potentials In Vivo. J Mol Biol 2019; 432:605-620. [PMID: 31711960 DOI: 10.1016/j.jmb.2019.10.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 10/07/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
Although chemical signaling during embryogenesis is readily addressed by a plethora of available techniques, the developmental functions of ionic signaling are still poorly understood. It is increasingly realized that bioelectric events in nonneural cells are critical for pattern regulation, but their study has been hampered by difficulties in monitoring and manipulating them in vivo. Recent developments in visualizing electrical signaling dynamics in the field of neuroscience have facilitated functional experiments that reveal instructive developmental bioelectric signals. However, there is a pressing need for additional tools to explore time-dependent ionic signaling to understand complex endogenous dynamics. Here, we present methodological advances, including 4D imaging and data analysis, for improved tracking of calcium flux in the Xenopus laevis embryo, lowering the barrier for in vivo physiology work in this important model system. Using these techniques, we investigated the relationship between bioelectric ion channel activity and calcium, finding that cell hyperpolarization and depolarization both induce persistent static elevation of cytoplasmic calcium levels that fade over developmental time. These calcium changes correlate with increased cell mobility in early embryos and abnormal craniofacial morphology in later embryos. We thus highlight membrane potential modulation as a tractable tool for modulation of signaling cascades that rely on calcium as a transduction mechanism. The methods we describe facilitate the study of important novel aspects of developmental physiology, are extendable to numerous classes of existing and forthcoming fluorescent physiological reporters, and establish highly accessible, inexpensive protocols for their investigation.
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22
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Sampedro Castañeda M, Zanoteli E, Scalco RS, Scaramuzzi V, Marques Caldas V, Conti Reed U, da Silva AMS, O'Callaghan B, Phadke R, Bugiardini E, Sud R, McCall S, Hanna MG, Poulsen H, Männikkö R, Matthews E. A novel ATP1A2 mutation in a patient with hypokalaemic periodic paralysis and CNS symptoms. Brain 2019; 141:3308-3318. [PMID: 30423015 PMCID: PMC6262219 DOI: 10.1093/brain/awy283] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/25/2018] [Indexed: 01/26/2023] Open
Abstract
Hypokalaemic periodic paralysis is a rare genetic neuromuscular disease characterized by episodes of skeletal muscle paralysis associated with low serum potassium. Muscle fibre inexcitability during attacks of paralysis is due to an aberrant depolarizing leak current through mutant voltage sensing domains of either the sarcolemmal voltage-gated calcium or sodium channel. We report a child with hypokalaemic periodic paralysis and CNS involvement, including seizures, but without mutations in the known periodic paralysis genes. We identified a novel heterozygous de novo missense mutation in the ATP1A2 gene encoding the α2 subunit of the Na+/K+-ATPase that is abundantly expressed in skeletal muscle and in brain astrocytes. Pump activity is crucial for Na+ and K+ homeostasis following sustained muscle or neuronal activity and its dysfunction is linked to the CNS disorders hemiplegic migraine and alternating hemiplegia of childhood, but muscle dysfunction has not been reported. Electrophysiological measurements of mutant pump activity in Xenopus oocytes revealed lower turnover rates in physiological extracellular K+ and an anomalous inward leak current in hypokalaemic conditions, predicted to lead to muscle depolarization. Our data provide important evidence supporting a leak current as the major pathomechanism underlying hypokalaemic periodic paralysis and indicate ATP1A2 as a new hypokalaemic periodic paralysis gene.
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Affiliation(s)
- Marisol Sampedro Castañeda
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Renata S Scalco
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Vinicius Scaramuzzi
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Vitor Marques Caldas
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | | | - Benjamin O'Callaghan
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Rahul Phadke
- Division of Neuropathology, UCL Institute of Neurology, London, UK
| | - Enrico Bugiardini
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Richa Sud
- Neurogenetics Unit, UCL Institute of Neurology, Queen Square, London, UK
| | - Samuel McCall
- Neurogenetics Unit, UCL Institute of Neurology, Queen Square, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Hanne Poulsen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Aarhus University, DK-8000 Aarhus, Denmark
| | - Roope Männikkö
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
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23
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Strength and muscle structure preserved during long-term therapy in a patient with hypokalemic periodic paralysis (Cav1.1-R1239G). J Neurol 2019; 266:1623-1632. [PMID: 30937521 DOI: 10.1007/s00415-019-09302-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/23/2019] [Accepted: 03/27/2019] [Indexed: 01/30/2023]
Abstract
We report a young wheelchair-dependent patient with an unclear proximal myopathy and a heterozygous, de-novo Cav1.1-R1239G mutation suggesting hypokalemic periodic paralysis (HypoPP). Sonography showed a loss of the pennate pattern indicative of an edema, whereas fatty degeneration was excluded. Within 7 days of therapy with spironolactone, potassium and physical therapy, muscle strength almost completely normalized, a normal pennate pattern appeared and the edema was markedly reduced. She learned to walk without aid and to do sports and has continued to do so for 11 years until now. Over the years, we tested serum potassium values, muscle strength, muscle edema and muscular sodium content by 1.5 T, 3 T and 7 T 1H and 23Na magnetic resonance imaging. No fatty muscle degeneration developed. Muscular edema-like changes only occurred when she was pregnant and was set to reduced therapy. Because of the ability to do sports again, her mobility was further increased. Our observational study on this single patient may suggest that: (1) muscle imaging and molecular genetics are important diagnostic tools, (2) weakness in periodic paralysis may be reversible, and (3) continued adequate therapy may preserve muscle structure and strength on a longterm, whereas weakness due to fatty degeneration could be considered progressive and irreversible. Although HypoPP is a rare disease, it should be included in differential diagnosis not only if there is paroxysmal weakness, but also in cases of myopathy of unknown origin.
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Kokunai Y, Dalle C, Vicart S, Sternberg D, Pouliot V, Bendahhou S, Fournier E, Chahine M, Fontaine B, Nicole S. A204E mutation in Na v1.4 DIS3 exerts gain- and loss-of-function effects that lead to periodic paralysis combining hyper- with hypo-kalaemic signs. Sci Rep 2018; 8:16681. [PMID: 30420713 PMCID: PMC6232142 DOI: 10.1038/s41598-018-34750-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/25/2018] [Indexed: 12/11/2022] Open
Abstract
Periodic paralyses (PP) are characterized by episodic muscle weakness and are classified into the distinct hyperkalaemic (hyperPP) and hypokalaemic (hypoPP) forms. The dominantly-inherited form of hyperPP is caused by overactivity of Nav1.4 - the skeletal muscle voltage-gated sodium channel. Familial hypoPP results from a leaking gating pore current induced by dominant mutations in Nav1.4 or Cav1.1, the skeletal muscle voltage-gated calcium channel. Here, we report an individual with clinical signs of hyperPP and hypokalaemic episodes of muscle paralysis who was heterozygous for the novel p.Ala204Glu (A204E) substitution located in one region of Nav1.4 poor in disease-related variations. A204E induced a significant decrease of sodium current density, increased the window current, enhanced fast and slow inactivation of Nav1.4, and did not cause gating pore current in functional analyses. Interestingly, the negative impact of A204E on Nav1.4 activation was strengthened in low concentration of extracellular K+. Our data prove the existence of a phenotype combining signs of hyperPP and hypoPP due to dominant Nav1.4 mutations. The hyperPP component would result from gain-of-function effects on Nav1.4 and the hypokalemic episodes of paralysis from loss-of-function effects strengthened by low K+. Our data argue for a non-negligible role of Nav1.4 loss-of-function in familial hypoPP.
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Affiliation(s)
- Yosuke Kokunai
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Carine Dalle
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Savine Vicart
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Damien Sternberg
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Valérie Pouliot
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Said Bendahhou
- CNRS UMR7370, LP2M, Labex ICST, University Nice Sophia-Antipolis, Faculté de Médecine, Nice, France
| | - Emmanuel Fournier
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Mohamed Chahine
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Bertrand Fontaine
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France.
| | - Sophie Nicole
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
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Moreau A, Chahine M. A New Cardiac Channelopathy: From Clinical Phenotypes to Molecular Mechanisms Associated With Na v1.5 Gating Pores. Front Cardiovasc Med 2018; 5:139. [PMID: 30356750 PMCID: PMC6189448 DOI: 10.3389/fcvm.2018.00139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
Voltage gated sodium channels (NaV) are broadly expressed in the human body. They are responsible for the initiation of action potentials in excitable cells. They also underlie several physiological processes such as cognitive, sensitive, motor, and cardiac functions. The NaV1.5 channel is the main NaV expressed in the heart. A dysfunction of this channel is usually associated with the development of pure electrical disorders such as long QT syndrome, Brugada syndrome, sinus node dysfunction, atrial fibrillation, and cardiac conduction disorders. However, mutations of Nav1.5 have recently been linked to the development of an atypical clinical entity combining complex arrhythmias and dilated cardiomyopathy. Although several Nav1.5 mutations have been linked to dilated cardiomyopathy phenotypes, their pathogenic mechanisms remain to be elucidated. The gating pore may constitute a common biophysical defect for all NaV1.5 mutations located in the channel's VSDs. The creation of such a gating pore may disrupt the ionic homeostasis of cardiomyocytes, affecting electrical signals, cell morphology, and cardiac myocyte function. The main objective of this article is to review the concept of gating pores and their role in structural heart diseases and to discuss potential pharmacological treatments.
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Affiliation(s)
- Adrien Moreau
- PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Mohamed Chahine
- CERVO Research Centre, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, Canada.,Department of Medicine, Université Laval, Quebec City, QC, Canada
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Zhou HY, Zhan FX, Tian WT, Zhang C, Wang Y, Zhu ZY, Liu XL, Xu YQ, Luan XH, Huang XJ, Chen SD, Cao L. The study of exercise tests in paroxysmal kinesigenic dyskinesia. Clin Neurophysiol 2018; 129:2435-2441. [PMID: 30293034 DOI: 10.1016/j.clinph.2018.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/14/2018] [Accepted: 09/01/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To unravel if there was muscular ion channel dysfunction in paroxysmal kinesigenic dyskinesia (PKD) patients using the exercises tests (ET). METHODS Sixty PKD patients including 28 PRRT2 mutations carriers were enrolled in this study, as well as 19 hypokalaemic periodic paralysis (HypoPP) patients as the positive controls and 45 healthy subjects as the negative controls. ET including long exercise test (LET) and short exercise test (SET) was performed in the corresponding subjects. RESULTS In the LET, both the overall PKD patients and HypoPP patients had greater CMAP amplitude and area increments during exercise than healthy controls. At most 25% of PKD patients were identified from the normality with greater amplitude increment than the area. On the contrary, 50% of HypoPP patients were differentiated with greater area increment than the amplitude. More percentage of PRRT2- patients than PRRT2+ patients had abnormal average amplitude increment. Unexpectedly, five PKD patients had abnormal maximum CMAP amplitude decrements after exercise in the LET, and one had abnormal maximum immediate amplitude decrement in the SET. CONCLUSIONS Distinct ET manifestations were found in PKD patients compared to normal controls and HypoPP patients. SIGNIFICANCE Abnormal muscle membrane excitability might be involved in the mechanisms responsible for PKD.
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Affiliation(s)
- Hai-Yan Zhou
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fei-Xia Zhan
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wo-Tu Tian
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chao Zhang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Wang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ze-Yu Zhu
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Li Liu
- Department of Neurology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Yang-Qi Xu
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xing-Hua Luan
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Jun Huang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sheng-Di Chen
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Li Cao
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Soufi M, Ruppert V, Rinné S, Mueller T, Kurt B, Pilz G, Maieron A, Dodel R, Decher N, Schaefer JR. Increased KCNJ18 promoter activity as a mechanism in atypical normokalemic periodic paralysis. NEUROLOGY-GENETICS 2018; 4:e274. [PMID: 30338294 PMCID: PMC6186026 DOI: 10.1212/nxg.0000000000000274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/02/2018] [Indexed: 11/21/2022]
Abstract
Objective To identify the genetic basis of a patient with symptoms of normokalemic sporadic periodic paralysis (PP) and to study the effect of KCNJ18 mutations. Methods A candidate gene approach was used to identify causative gene mutations, using Sanger sequencing. KCNJ18 promoter activity was analyzed in transfected HEK293 cells with a luciferase assay, and functional analysis of Kir2.6 channels was performed with the two-electrode voltage-clamp technique. Results Although we did not identify harmful mutations in SCN4A, CACNA1S, KCNJ2 and KCNE3, we detected a monoallelic four-fold variant in KCNJ18 (R39Q/R40H/A56E/I249V), together with a variant in the respective promoter of this channel (c.-542T/A). The exonic variants in Kir2.6 did not alter the channel function; however, luciferase assays revealed a 10-fold higher promoter activity of the c.-542A promoter construct, which is likely to cause a gain-of-function by increased expression of Kir2.6. We found that reducing extracellular K+ levels causes a paradoxical reduction in outward currents, similar to that described for other inward rectifying K+ channels. Thus, reducing the extracellular K+ levels might be a therapeutic strategy to antagonize the transcriptionally increased KCNJ18 currents. Consistently, treatment of the patient with K+ reducing drugs dramatically improved the health situation and prevented PP attacks. Conclusions We show that a promoter defect in the KCNJ18 gene is likely to cause periodic paralysis, as the observed transcriptional upregulation will be linked to increased Kir2.6 function. This concept is further supported by our observation that most of the PP attacks in our patient disappeared on medical treatment with K+ reducing drugs.
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Affiliation(s)
- Muhidien Soufi
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Volker Ruppert
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Susanne Rinné
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Tobias Mueller
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Bilgen Kurt
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Guenter Pilz
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Andreas Maieron
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Richard Dodel
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Niels Decher
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
| | - Juergen R Schaefer
- Center for Undiagnosed and Rare Diseases (ZusE) (M.S., T.M., B.K., J.R.S.); Department of Cardiology (V.R.) and Department of Neurology (R.D.), University Hospital Giessen and Marburg; Vegetative Physiology (S.R., N.D.), Philipps-University Marburg, Institute of Physiology and Pathophysiology, & Marburg Center for Mind, Brain and Behavior, Marburg, Germany; Institute for Algebra (G.P.), Johannes Kepler University Linz; and Department of Gastroenterology (A.M.), Hospital Elisabethinen, Linz, Austria
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A leaky voltage sensor domain of cardiac sodium channels causes arrhythmias associated with dilated cardiomyopathy. Sci Rep 2018; 8:13804. [PMID: 30218094 PMCID: PMC6138662 DOI: 10.1038/s41598-018-31772-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/21/2018] [Indexed: 11/18/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a structural heart disease that causes dilatation of cardiac chambers and impairs cardiac contractility. The SCN5A gene encodes Nav1.5, the predominant cardiac sodium channel alpha subunit. SCN5A mutations have been identified in patients with arrhythmic disorders associated with DCM. The characterization of Nav1.5 mutations located in the voltage sensor domain (VSD) and associated with DCM revealed divergent biophysical defects that do not fully explain the pathologies observed in these patients. The purpose of this study was to characterize the pathological consequences of a gating pore in the heart arising from the Nav1.5/R219H mutation in a patient with complex cardiac arrhythmias and DCM. We report its properties using cardiomyocytes derived from patient-specific human induced pluripotent stem cells. We showed that this mutation generates a proton leak (called gating pore current). We also described disrupted ionic homeostasis, altered cellular morphology, electrical properties, and contractile function, most probably linked to the proton leak. We thus propose a novel link between SCN5A mutation and the complex pathogenesis of cardiac arrhythmias and DCM. Furthermore, we suggest that leaky channels would constitute a common pathological mechanism underlying several neuronal, neuromuscular, and cardiac pathologies.
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Bayless-Edwards L, Winston V, Lehmann-Horn F, Arinze P, Groome JR, Jurkat-Rott K. Na V1.4 DI-S4 periodic paralysis mutation R222W enhances inactivation and promotes leak current to attenuate action potentials and depolarize muscle fibers. Sci Rep 2018; 8:10372. [PMID: 29991727 PMCID: PMC6039468 DOI: 10.1038/s41598-018-28594-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/20/2018] [Indexed: 01/24/2023] Open
Abstract
Hypokalemic periodic paralysis is a skeletal muscle disease characterized by episodic weakness associated with low serum potassium. We compared clinical and biophysical effects of R222W, the first hNaV1.4 domain I mutation linked to this disease. R222W patients exhibited a higher density of fibers with depolarized resting membrane potentials and produced action potentials that were attenuated compared to controls. Functional characterization of the R222W mutation in heterologous expression included the inactivation deficient IFM/QQQ background to isolate activation. R222W decreased sodium current and slowed activation without affecting probability. Consistent with the phenotype of muscle weakness, R222W shifted fast inactivation to hyperpolarized potentials, promoted more rapid entry, and slowed recovery. R222W increased the extent of slow inactivation and slowed its recovery. A two-compartment skeletal muscle fiber model revealed that defects in fast inactivation sufficiently explain action potential attenuation in patients. Molecular dynamics simulations showed that R222W disrupted electrostatic interactions within the gating pore, supporting the observation that R222W promotes omega current at hyperpolarized potentials. Sodium channel inactivation defects produced by R222W are the primary driver of skeletal muscle fiber action potential attenuation, while hyperpolarization-induced omega current produced by that mutation promotes muscle fiber depolarization.
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Affiliation(s)
| | - Vern Winston
- Department of Biological Sciences, Idaho State University, 83209, Pocatello, ID, USA
| | | | - Paula Arinze
- Department of Biological Sciences, Idaho State University, 83209, Pocatello, ID, USA
| | - James R Groome
- Department of Biological Sciences, Idaho State University, 83209, Pocatello, ID, USA.
| | - Karin Jurkat-Rott
- Department of Neuroanesthesiology, Clinic for Neurosurgery, Ulm University, Guenzburg, Germany
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Allard B. Evaluation of mutant muscle Ca 2+ channel properties using two different expression systems. J Gen Physiol 2018; 150:897-899. [PMID: 29848491 PMCID: PMC6028501 DOI: 10.1085/jgp.201812095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Allard appraises recent studies investigating the pathological mechanism of hypokalemic periodic paralysis mutations.
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Affiliation(s)
- Bruno Allard
- Institut NeuroMyoGène, Université Lyon 1, Lyon, France
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Allard B. From excitation to intracellular Ca 2+ movements in skeletal muscle: Basic aspects and related clinical disorders. Neuromuscul Disord 2018; 28:394-401. [DOI: 10.1016/j.nmd.2018.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/19/2018] [Accepted: 03/05/2018] [Indexed: 01/18/2023]
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Allard B, Fuster C. When muscle Ca 2+ channels carry monovalent cations through gating pores: insights into the pathophysiology of type 1 hypokalaemic periodic paralysis. J Physiol 2018; 596:2019-2027. [PMID: 29572832 DOI: 10.1113/jp274955] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
Patients suffering from type 1 hypokalaemic periodic paralysis (HypoPP1) experience attacks of muscle paralysis associated with hypokalaemia. The disease arises from missense mutations in the gene encoding the α1 subunit of the dihydropyridine receptor (DHPR), a protein complex anchored in the tubular membrane of skeletal muscle fibres which controls the release of Ca2+ from sarcoplasmic reticulum and also functions as a Ca2+ channel. The vast majority of mutations consist of the replacement of one of the outer arginines in S4 segments of the α1 subunit by neutral residues. Early studies have shown that muscle fibres from HypoPP1 patients are abnormally depolarized at rest in low K+ to the point of inducing muscle inexcitability. The relationship between HypoPP1 mutations and depolarization has long remained unknown. More recent investigations conducted in the closely structurally related voltage-gated Na+ and K+ channels have shown that comparable S4 arginine substitutions gave rise to elevated inward currents at negative potentials called gating pore currents. Experiments performed in muscle fibres from different models revealed such an inward resting current through HypoPP1 mutated Ca2+ channels. In mouse fibres transfected with HypoPP1 mutated channels, the elevated resting current was found to carry H+ for the R1239H arginine-to-histidine mutation in a S4 segment and Na+ for the V876E HypoPP1 mutation, which has the peculiarity of not being located in S4 segments. Muscle paralysis probably results from the presence of a gating pore current associated with hypokalaemia for both mutations, possibly aggravated by external acidosis for the R1239H mutation.
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Affiliation(s)
- Bruno Allard
- Institut NeuroMyoGene, Université de Lyon, Université Lyon 1, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622 Villeurbanne, France
| | - Clarisse Fuster
- Institut NeuroMyoGene, Université de Lyon, Université Lyon 1, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622 Villeurbanne, France
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Abstract
Gating pore currents through the voltage-sensing domains (VSDs) of the skeletal muscle voltage-gated sodium channel NaV1.4 underlie hypokalemic periodic paralysis (HypoPP) type 2. Gating modifier toxins target ion channels by modifying the function of the VSDs. We tested the hypothesis that these toxins could function as blockers of the pathogenic gating pore currents. We report that a crab spider toxin Hm-3 from Heriaeus melloteei can inhibit gating pore currents due to mutations affecting the second arginine residue in the S4 helix of VSD-I that we have found in patients with HypoPP and describe here. NMR studies show that Hm-3 partitions into micelles through a hydrophobic cluster formed by aromatic residues and reveal complex formation with VSD-I through electrostatic and hydrophobic interactions with the S3b helix and the S3-S4 extracellular loop. Our data identify VSD-I as a specific binding site for neurotoxins on sodium channels. Gating modifier toxins may constitute useful hits for the treatment of HypoPP.
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Chahine M. Improving the characterization of calcium channel gating pore currents with Stac3. J Gen Physiol 2018; 150:375-378. [PMID: 29467165 PMCID: PMC5839726 DOI: 10.1085/jgp.201711984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Chahine highlights new work that exploits the increased expression of human CaV1.1 at the plasma membrane after coexpression with Stac3.
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Wu F, Quinonez M, DiFranco M, Cannon SC. Stac3 enhances expression of human Ca V1.1 in Xenopus oocytes and reveals gating pore currents in HypoPP mutant channels. J Gen Physiol 2018; 150:475-489. [PMID: 29386226 PMCID: PMC5839724 DOI: 10.1085/jgp.201711962] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/03/2018] [Indexed: 01/24/2023] Open
Abstract
Hypokalemic periodic paralysis (HypoPP) is thought to be caused by an aberrant inward current through the voltage sensors of mutant Na+ or Ca2+ channels. Wu et al. use Stac3 to enhance the membrane expression of two HypoPP CaV1.1 mutants in oocytes and find that both support gating pore currents. Mutations of CaV1.1, the pore-forming subunit of the L-type Ca2+ channel in skeletal muscle, are an established cause of hypokalemic periodic paralysis (HypoPP). However, functional assessment of HypoPP mutant channels has been hampered by difficulties in achieving sufficient plasma membrane expression in cells that are not of muscle origin. In this study, we show that coexpression of Stac3 dramatically increases the expression of human CaV1.1 (plus α2-δ1b and β1a subunits) at the plasma membrane of Xenopus laevis oocytes. In voltage-clamp studies with the cut-open oocyte clamp, we observe ionic currents on the order of 1 μA and gating charge displacements of ∼0.5–1 nC. Importantly, this high expression level is sufficient to ascertain whether HypoPP mutant channels are leaky because of missense mutations at arginine residues in S4 segments of the voltage sensor domains. We show that R528H and R528G in S4 of domain II both support gating pore currents, but unlike other R/H HypoPP mutations, R528H does not conduct protons. Stac3-enhanced membrane expression of CaV1.1 in oocytes increases the throughput for functional studies of disease-associated mutations and is a new platform for investigating the voltage-dependent properties of CaV1.1 without the complexity of the transverse tubule network in skeletal muscle.
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Affiliation(s)
- Fenfen Wu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marbella Quinonez
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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36
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Abstract
Voltage-gated sodium channels belong to the superfamily of voltage-gated cation channels. Their structure is based on domains comprising a voltage sensor domain (S1-S4 segments) and a pore domain (S5-S6 segments). Mutations in positively charged residues of the S4 segments may allow protons or cations to pass directly through the gating pore constriction of the voltage sensor domain; these anomalous currents are referred to as gating pore or omega (ω) currents. In the skeletal muscle disorder hypokalemic periodic paralysis, and in arrhythmic dilated cardiomyopathy, inherited mutations of S4 arginine residues promote omega currents that have been shown to be a contributing factor in the pathogenesis of these sodium channel disorders. Characterization of gating pore currents in these channelopathies and with artificial mutations has been possible by measuring the voltage-dependence and selectivity of these leak currents. The basis of gating pore currents and the structural basis of S4 movement through the gating pore has also been studied extensively with molecular dynamics. These simulations have provided valuable insight into the nature of S4 translocation and the physical basis for the effects of mutations that promote permeation of protons or cations through the gating pore.
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Affiliation(s)
- J R Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA.
| | - A Moreau
- Institut NeuroMyogene, ENS de Lyon, Site MONOD, Lyon, France
| | - L Delemotte
- Science for Life Laboratory, Department of Physics, KTH Royal Institute of Technology, Box 1031, 171 21, Solna, Sweden
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37
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Abstract
The periodic paralyses are a group of skeletal muscle channelopathies characterizeed by intermittent attacks of muscle weakness often associated with altered serum potassium levels. The underlying genetic defects include mutations in genes encoding the skeletal muscle calcium channel Cav1.1, sodium channel Nav1.4, and potassium channels Kir2.1, Kir3.4, and possibly Kir2.6. Our increasing knowledge of how mutant channels affect muscle excitability has resulted in better understanding of many clinical phenomena which have been known for decades and sheds light on some of the factors that trigger attacks. Insights into the pathophysiology are also leading to new therapeutic approaches.
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Affiliation(s)
- Doreen Fialho
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Robert C Griggs
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States.
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, United Kingdom
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38
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Chen K, Zuo D, Liu Z, Chen H. Kir2.1 channels set two levels of resting membrane potential with inward rectification. Pflugers Arch 2017; 470:599-611. [PMID: 29282531 DOI: 10.1007/s00424-017-2099-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/08/2017] [Accepted: 12/17/2017] [Indexed: 01/27/2023]
Abstract
Strong inward rectifier K+ channels (Kir2.1) mediate background K+ currents primarily responsible for maintenance of resting membrane potential. Multiple types of cells exhibit two levels of resting membrane potential. Kir2.1 and K2P1 currents counterbalance, partially accounting for the phenomenon of human cardiomyocytes in subphysiological extracellular K+ concentrations or pathological hypokalemic conditions. The mechanism of how Kir2.1 channels contribute to the two levels of resting membrane potential in different types of cells is not well understood. Here we test the hypothesis that Kir2.1 channels set two levels of resting membrane potential with inward rectification. Under hypokalemic conditions, Kir2.1 currents counterbalance HCN2 or HCN4 cation currents in CHO cells that heterologously express both channels, generating N-shaped current-voltage relationships that cross the voltage axis three times and reconstituting two levels of resting membrane potential. Blockade of HCN channels eliminated the phenomenon in K2P1-deficient Kir2.1-expressing human cardiomyocytes derived from induced pluripotent stem cells or CHO cells expressing both Kir2.1 and HCN2 channels. Weakly inward rectifier Kir4.1 or inward rectification-deficient Kir2.1•E224G mutant channels do not set such two levels of resting membrane potential when co-expressed with HCN2 channels in CHO cells or when overexpressed in human cardiomyocytes derived from induced pluripotent stem cells. These findings demonstrate a common mechanism that Kir2.1 channels set two levels of resting membrane potential with inward rectification by balancing inward currents through different cation channels such as hyperpolarization-activated HCN channels or hypokalemia-induced K2P1 leak channels.
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Affiliation(s)
- Kuihao Chen
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Dongchuan Zuo
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Zheng Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haijun Chen
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA.
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39
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Monteleone S, Lieb A, Pinggera A, Negro G, Fuchs JE, Hofer F, Striessnig J, Tuluc P, Liedl KR. Mechanisms Responsible for ω-Pore Currents in Ca v Calcium Channel Voltage-Sensing Domains. Biophys J 2017; 113:1485-1495. [PMID: 28978442 PMCID: PMC5627182 DOI: 10.1016/j.bpj.2017.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/28/2017] [Accepted: 08/07/2017] [Indexed: 12/27/2022] Open
Abstract
Mutations of positively charged amino acids in the S4 transmembrane segment of a voltage-gated ion channel form ion-conducting pathways through the voltage-sensing domain, named ω-current. Here, we used structure modeling and MD simulations to predict pathogenic ω-currents in CaV1.1 and CaV1.3 Ca2+ channels bearing several S4 charge mutations. Our modeling predicts that mutations of CaV1.1-R1 (R528H/G, R897S) or CaV1.1-R2 (R900S, R1239H) linked to hypokalemic periodic paralysis type 1 and of CaV1.3-R3 (R990H) identified in aldosterone-producing adenomas conducts ω-currents in resting state, but not during voltage-sensing domain activation. The mechanism responsible for the ω-current and its amplitude depend on the number of charges in S4, the position of the mutated S4 charge and countercharges, and the nature of the replacing amino acid. Functional characterization validates the modeling prediction showing that CaV1.3-R990H channels conduct ω-currents at hyperpolarizing potentials, but not upon membrane depolarization compared with wild-type channels.
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Affiliation(s)
- Stefania Monteleone
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Andreas Lieb
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria; Institute of Neurology, University College London, London, United Kingdom
| | - Alexandra Pinggera
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria; Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Giulia Negro
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Julian E Fuchs
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofer
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria.
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Cannon SC. An atypical Ca V1.1 mutation reveals a common mechanism for hypokalemic periodic paralysis. J Gen Physiol 2017; 149:1061-1064. [PMID: 29138267 PMCID: PMC5715912 DOI: 10.1085/jgp.201711923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cannon reviews new evidence supporting a key role for anomalous inward currents in the etiology of hypokalemic periodic paralysis.
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Affiliation(s)
- Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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41
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Fuster C, Perrot J, Berthier C, Jacquemond V, Charnet P, Allard B. Na leak with gating pore properties in hypokalemic periodic paralysis V876E mutant muscle Ca channel. J Gen Physiol 2017; 149:1139-1148. [PMID: 29114033 PMCID: PMC5715907 DOI: 10.1085/jgp.201711834] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/18/2017] [Accepted: 10/12/2017] [Indexed: 12/26/2022] Open
Abstract
Type 1 hypokalemic periodic paralysis (HypoPP1) is a poorly understood genetic neuromuscular disease characterized by episodic attacks of paralysis associated with low blood K+ The vast majority of HypoPP1 mutations involve the replacement of an arginine by a neutral residue in one of the S4 segments of the α1 subunit of the skeletal muscle voltage-gated Ca2+ channel, which is thought to generate a pathogenic gating pore current. The V876E HypoPP1 mutation has the peculiarity of being located in the S3 segment of domain III, rather than an S4 segment, raising the question of whether such a mutation induces a gating pore current. Here we successfully transfer cDNAs encoding GFP-tagged human wild-type (WT) and V876E HypoPP1 mutant α1 subunits into mouse muscles by electroporation. The expression profile of these WT and V876E channels shows a regular striated pattern, indicative of their localization in the t-tubule membrane. In addition, L-type Ca2+ current properties are the same in V876E and WT fibers. However, in the presence of an external solution containing low-Cl- and lacking Na+ and K+, V876E fibers display an elevated leak current at negative voltages that is increased by external acidification to a higher extent in V876E fibers, suggesting that the leak current is carried by H+ ions. However, in the presence of Tyrode's solution, the rate of change in intracellular pH produced by external acidification was not significantly different in V876E and WT fibers. Simultaneous measurement of intracellular Na+ and current in response to Na+ readmission in the external solution reveals a rate of Na+ influx associated with an inward current, which are both significantly larger in V876E fibers. These data suggest that the V876E mutation generates a gating pore current that carries strong resting Na+ inward currents in physiological conditions that are likely responsible for the severe HypoPP1 symptoms associated with this mutation.
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Affiliation(s)
- Clarisse Fuster
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR Centre National de la Recherche Scientifique 5310, Institut National de la Santé et de la Recherche Médicale U1217, Villeurbanne, France
| | - Jimmy Perrot
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR Centre National de la Recherche Scientifique 5310, Institut National de la Santé et de la Recherche Médicale U1217, Villeurbanne, France
| | - Christine Berthier
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR Centre National de la Recherche Scientifique 5310, Institut National de la Santé et de la Recherche Médicale U1217, Villeurbanne, France
| | - Vincent Jacquemond
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR Centre National de la Recherche Scientifique 5310, Institut National de la Santé et de la Recherche Médicale U1217, Villeurbanne, France
| | - Pierre Charnet
- Institut des Biomolécules Max Mousseron, Université Montpellier 1 et 2, UMR Centre National de la Recherche Scientifique 5247, Montpellier, France
| | - Bruno Allard
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR Centre National de la Recherche Scientifique 5310, Institut National de la Santé et de la Recherche Médicale U1217, Villeurbanne, France
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42
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Chalissery AJ, Munteanu T, Langan Y, Brett F, Redmond J. Diverse phenotype of hypokalaemic periodic paralysis within a family. Pract Neurol 2017; 18:60-65. [DOI: 10.1136/practneurol-2017-001677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2017] [Indexed: 11/04/2022]
Abstract
Hypokalaemic periodic paralysis typically presents with intermittent mild-to-moderate weakness lasting hours to days. We report a case with an uncommon phenotype of late-onset myopathy without episodic paralytic attacks. Initial work-up including muscle biopsy was inconclusive. A subsequent review of the right deltoid biopsy, long exercise testing and repeated family history was helpful, followed by appropriate genetic testing. We identified a heterozygous pathogenic mutation in calcium ion channel (CACNA1S:c.1583G>A p.Arg528His) causing hypokalaemic periodic paralysis. Myopathy can present without episodic paralysis and the frequency of paralytic episodes does not correlate well with the development and progression of a fixed myopathy. Our report also highlights the intrafamilial phenotypic variation of hypokalaemic periodic paralysis secondary to a CACNA1S gene mutation.
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43
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Fuster C, Perrot J, Berthier C, Jacquemond V, Allard B. Elevated resting H + current in the R1239H type 1 hypokalaemic periodic paralysis mutated Ca 2+ channel. J Physiol 2017; 595:6417-6428. [PMID: 28857175 DOI: 10.1113/jp274638] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/28/2017] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Missense mutations in the gene encoding the α1 subunit of the skeletal muscle voltage-gated Ca2+ channel induce type 1 hypokalaemic periodic paralysis, a poorly understood neuromuscular disease characterized by episodic attacks of paralysis associated with low serum K+ . Acute expression of human wild-type and R1239H HypoPP1 mutant α1 subunits in mature mouse muscles showed that R1239H fibres displayed Ca2+ currents of reduced amplitude and larger resting leak inward current increased by external acidification. External acidification also produced intracellular acidification at a higher rate in R1239H fibres and inhibited inward rectifier K+ currents. These data suggest that the R1239H mutation induces an elevated leak H+ current at rest flowing through a gating pore and could explain why paralytic attacks preferentially occur during the recovery period following muscle exercise. ABSTRACT Missense mutations in the gene encoding the α1 subunit of the skeletal muscle voltage-gated Ca2+ channel induce type 1 hypokalaemic periodic paralysis, a poorly understood neuromuscular disease characterized by episodic attacks of paralysis associated with low serum K+ . The present study aimed at identifying the changes in muscle fibre electrical properties induced by acute expression of the R1239H hypokalaemic periodic paralysis human mutant α1 subunit of Ca2+ channels in a mature muscle environment to better understand the pathophysiological mechanisms involved in this disorder. We transferred genes encoding wild-type and R1239H mutant human Ca2+ channels into hindlimb mouse muscle by electroporation and combined voltage-clamp and intracellular pH measurements on enzymatically dissociated single muscle fibres. As compared to fibres expressing wild-type α1 subunits, R1239H mutant-expressing fibres displayed Ca2+ currents of reduced amplitude and a higher resting leak inward current that was increased by external acidification. External acidification also produced intracellular acidification at a higher rate in R1239H fibres and inhibited inward rectifier K+ currents. These data indicate that the R1239H mutation induces an elevated leak H+ current at rest flowing through a gating pore created by the mutation and that external acidification favours onset of muscle paralysis by potentiating H+ depolarizing currents and inhibiting resting inward rectifier K+ currents. Our results could thus explain why paralytic attacks preferentially occur during the recovery period following intense muscle exercise.
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Affiliation(s)
- Clarisse Fuster
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622, Villeurbanne, France
| | - Jimmy Perrot
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622, Villeurbanne, France
| | - Christine Berthier
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622, Villeurbanne, France
| | - Vincent Jacquemond
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622, Villeurbanne, France
| | - Bruno Allard
- Institut NeuroMyoGene, Université Lyon 1, Université de Lyon, UMR CNRS 5310, Inserm U1217, 43 bd du 11 Novembre 1918, 69622, Villeurbanne, France
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44
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Zuo D, Chen K, Zhou M, Liu Z, Chen H. Kir2.1 and K2P1 channels reconstitute two levels of resting membrane potential in cardiomyocytes. J Physiol 2017; 595:5129-5142. [PMID: 28543529 DOI: 10.1113/jp274268] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/22/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Outward and inward background currents across the cell membrane balance, determining resting membrane potential. Inward rectifier K+ channel subfamily 2 (Kir2) channels primarily maintain the resting membrane potential of cardiomyocytes. Human cardiomyocytes exhibit two levels of resting membrane potential at subphysiological extracellular K+ concentrations or pathological hypokalaemia, however, the underlying mechanism is unclear. In the present study, we show that human cardiomyocytes derived from induced pluripotent stem cells with enhanced expression of isoform 1 of Kir2 (Kir2.1) channels and mouse HL-1 cardiomyocytes with ectopic expression of two pore-domain K+ channel isoform 1 (K2P1) recapitulate two levels of resting membrane potential, indicating the contributions of Kir2.1 and K2P1 channels to the phenomenon. In Chinese hamster ovary cells that express the channels, Kir2.1 currents non-linearly counterbalance hypokalaemia-induced K2P1 leak cation currents, reconstituting two levels of resting membrane potential. These findings support the hypothesis that Kir2 currents non-linearly counterbalance inward background cation currents, such as K2P1 currents, accounting for two levels of resting membrane potential in human cardiomyocytes and demonstrating a novel mechanism that regulates excitability. ABSTRACT Inward rectifier K+ channel subfamily 2 (Kir2) channels primarily maintain the normal resting membrane potential of cardiomyocytes. At subphysiological extracellular K+ concentrations or pathological hypokalaemia, human cardiomyocytes show both hyperpolarized and depolarized resting membrane potentials; these depolarized potentials cause cardiac arrhythmia; however, the underlying mechanism is unknown. In the present study, we show that inward rectifier K+ channel subfamily 2 isoform 1 (Kir2.1) currents non-linearly counterbalance hypokalaemia-induced two pore-domain K+ channel isoform 1 (K2P1) leak cation currents, reconstituting two levels of resting membrane potential in cardiomyocytes. Under hypokalaemic conditions, both human cardiomyocytes derived from induced pluripotent stem cells with enhanced Kir2.1 expression and mouse HL-1 cardiomyocytes with ectopic expression of K2P1 channels recapitulate two levels of resting membrane potential. These cardiomyocytes display N-shaped current-voltage relationships that cross the voltage axis three times and the first and third zero-current potentials match the two levels of resting membrane potential. Inhibition of K2P1 expression eliminates the phenomenon, indicating contributions of Kir2.1 and K2P1 channels to two levels of resting membrane potential. Second, in Chinese hamster ovary cells that heterologously express the channels, Kir2.1 currents non-linearly counterbalance hypokalaemia-induced K2P1 leak cation currents, yielding the N-shaped current-voltage relationships, causing the resting membrane potential to spontaneously jump from hyperpolarization at the first zero-current potential to depolarization at the third zero-current potential, again recapitulating two levels of resting membrane potential. These findings reveal ionic mechanisms of the two levels of resting membrane potential, demonstrating a previously unknown mechanism for the regulation of excitability, and support the hypothesis that Kir2 currents non-linearly balance inward background cation currents, accounting for two levels of resting membrane potential of human cardiomyocytes.
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Affiliation(s)
- Dongchuan Zuo
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA
| | - Kuihao Chen
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA
| | - Min Zhou
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Zheng Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Haijun Chen
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, USA
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45
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Maqoud F, Cetrone M, Mele A, Tricarico D. Molecular structure and function of big calcium-activated potassium channels in skeletal muscle: pharmacological perspectives. Physiol Genomics 2017; 49:306-317. [DOI: 10.1152/physiolgenomics.00121.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/08/2017] [Accepted: 04/10/2017] [Indexed: 11/22/2022] Open
Abstract
The large-conductance Ca2+-activated K+ (BK) channel is broadly expressed in various mammalian cells and tissues such as neurons, skeletal muscles (sarco-BK), and smooth muscles. These channels are activated by changes in membrane electrical potential and by increases in the concentration of intracellular calcium ion (Ca2+). The BK channel is subjected to many mechanisms that add diversity to the BK channel α-subunit gene. These channels are indeed subject to alternative splicing, auxiliary subunits modulation, posttranslational modifications, and protein-protein interactions. BK channels can be modulated by diverse molecules that may induce either an increase or decrease in channel activity. The linkage of these channels to many intracellular metabolites and pathways, as well as their modulation by extracellular natural agents, have been found to be relevant in many physiological processes. BK channel diversity is obtained by means of alternative splicing and modulatory β- and γ-subunits. The association of the α-subunit with β- or with γ-subunits can change the BK channel phenotype, functional diversity, and pharmacological properties in different tissues. In the case of the skeletal muscle BK channel (sarco-BK channel), we established that the main mechanism regulating BK channel diversity is the alternative splicing of the KCNMA1/slo1 gene encoding for the α-subunit generating different splicing isoform in the muscle phenotypes. This finding helps to design molecules selectively targeting the skeletal muscle subtypes. The use of drugs selectively targeting the skeletal muscle BK channels is a promising strategy in the treatment of familial disorders affecting muscular skeletal apparatus including hyperkalemia and hypokalemia periodic paralysis.
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Affiliation(s)
- Fatima Maqoud
- Department of Pharmacy-Drug Science, University of Bari, Bari, Italy
- Faculty of Science, Chouaib Doukkali University, El Jadida, Morocco
| | - Michela Cetrone
- Istituto Tumori Giovanni Paolo II, Istituto di Ricovero e Cura a Carattere Scientifico, National Cancer Institute, Bari, Italy; and
| | - Antonietta Mele
- Department of Pharmacy-Drug Science, University of Bari, Bari, Italy
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46
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Tricarico D, Mele A. Commentary: A BK (Slo1) channel journey from molecule to physiology. Front Pharmacol 2017; 8:188. [PMID: 28424624 PMCID: PMC5380717 DOI: 10.3389/fphar.2017.00188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/23/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Antonietta Mele
- Department of Pharmacy-Drug Science, University of BariBari, Italy
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47
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Abstract
The NaV1.4 sodium channel is highly expressed in skeletal muscle, where it carries almost all of the inward Na+ current that generates the action potential, but is not present at significant levels in other tissues. Consequently, mutations of SCN4A encoding NaV1.4 produce pure skeletal muscle phenotypes that now include six allelic disorders: sodium channel myotonia, paramyotonia congenita, hyperkalemic periodic paralysis, hypokalemic periodic paralysis, congenital myasthenia, and congenital myopathy with hypotonia. Mutation-specific alternations of NaV1.4 function explain the mechanistic basis for the diverse phenotypes and identify opportunities for strategic intervention to modify the burden of disease.
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Affiliation(s)
- Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA.
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48
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Sinclair CD, Morrow JM, Janiczek RL, Evans MR, Rawah E, Shah S, Hanna MG, Reilly MM, Yousry TA, Thornton JS. Stability and sensitivity of water T 2 obtained with IDEAL-CPMG in healthy and fat-infiltrated skeletal muscle. NMR IN BIOMEDICINE 2016; 29:1800-1812. [PMID: 27809381 PMCID: PMC5132140 DOI: 10.1002/nbm.3654] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/05/2016] [Accepted: 08/29/2016] [Indexed: 05/15/2023]
Abstract
Quantifying muscle water T2 (T2 -water) independently of intramuscular fat content is essential in establishing T2 -water as an outcome measure for imminent new therapy trials in neuromuscular diseases. IDEAL-CPMG combines chemical shift fat-water separation with T2 relaxometry to obtain such a measure. Here we evaluate the reproducibility and B1 sensitivity of IDEAL-CPMG T2 -water and fat fraction (f.f.) values in healthy subjects, and demonstrate the potential of the method to quantify T2 -water variation in diseased muscle displaying varying degrees of fatty infiltration. The calf muscles of 11 healthy individuals (40.5 ± 10.2 years) were scanned twice at 3 T with an inter-scan interval of 4 weeks using IDEAL-CPMG, and 12 patients with hypokalemic periodic paralysis (HypoPP) (42.3 ± 11.5 years) were also imaged. An exponential was fitted to the signal decay of the separated water and fat components to determine T2 -water and the fat signal amplitude muscle regions manually segmented. Overall mean calf-level muscle T2 -water in healthy subjects was 31.2 ± 2.0 ms, without significant inter-muscle differences (p = 0.37). Inter-subject and inter-scan coefficients of variation were 5.7% and 3.2% respectively for T2 -water and 41.1% and 15.4% for f.f. Bland-Altman mean bias and ±95% coefficients of repeatability were for T2 -water (0.15, -2.65, 2.95) ms and f.f. (-0.02, -1.99, 2.03)%. There was no relationship between T2 -water (ρ = 0.16, p = 0.07) or f.f. (ρ = 0.03, p = 0.7761) and B1 error or any correlation between T2 -water and f.f. in the healthy subjects (ρ = 0.07, p = 0.40). In HypoPP there was a measurable relationship between T2 -water and f.f. (ρ = 0.59, p < 0.001). IDEAL-CPMG provides a feasible way to quantify T2 -water in muscle that is reproducible and sensitive to meaningful physiological changes without post hoc modeling of the fat contribution. In patients, IDEAL-CPMG measured elevations in T2 -water and f.f. while showing a weak relationship between these parameters, thus showing promise as a practical means of quantifying muscle water in patient populations.
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Affiliation(s)
- Christopher D.J. Sinclair
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
- UCL Institute of Neurology, Neuroradiological Academic UnitLondonWC1N 3BGUK
| | - Jasper M. Morrow
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
| | | | - Matthew R.B. Evans
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
| | - Elham Rawah
- UCL Institute of Neurology, Neuroradiological Academic UnitLondonWC1N 3BGUK
| | - Sachit Shah
- UCL Institute of Neurology, Neuroradiological Academic UnitLondonWC1N 3BGUK
| | - Michael G. Hanna
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
| | - Mary M. Reilly
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
| | - Tarek A. Yousry
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
- UCL Institute of Neurology, Neuroradiological Academic UnitLondonWC1N 3BGUK
| | - John S. Thornton
- UCL Institute of Neurology, MRC Centre for Neuromuscular DiseasesLondonWC1N 3BGUK
- UCL Institute of Neurology, Neuroradiological Academic UnitLondonWC1N 3BGUK
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Da Y, Lei L, Jurkat-Rott K, Lehmann-Horn F. Successful treatment of periodic paralysis with coenzyme Q10: two case reports. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2016; 35:107-108. [PMID: 28344441 PMCID: PMC5343741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Primary periodic paralyses (PPs) are autosomal dominant ion channel disorders characterized by episodic flaccid weakness associated with variations in serum potassium level. The main prophylactic therapy of choice for PPsis carbonic anhydrase inhibitors that are not always effective. In this report, we described two PP patients who were successfully treated with coenzyme Q10. They remained asymptomatic since initiation of treatment, which may be associated with promotion of energy synthesis, anti-oxidant activity, influence of the fiber type composition and regulation of the expression of gene. To our knowledge, this is the first report of primary periodic paralyses which have been successfully treated with CoQ10. More observations need to substantiate this clinical finding in PPs.
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Affiliation(s)
- Yuwei Da
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China;,Address for correspondence: Yuwei Da, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Chang Chun Street, Beijing 100053, China. Tel. +86 10 83198493. Fax +86 10 83171070. E-mail: ; Frank Lehmann-Horn, Division of Neurophysiology, Ulm University, Germany. E-mail:
| | - Lin Lei
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | | | - Frank Lehmann-Horn
- Division of Neurophysiology, Ulm University, Germany,Address for correspondence: Yuwei Da, Department of Neurology, Xuan Wu Hospital, Capital Medical University, Chang Chun Street, Beijing 100053, China. Tel. +86 10 83198493. Fax +86 10 83171070. E-mail: ; Frank Lehmann-Horn, Division of Neurophysiology, Ulm University, Germany. E-mail:
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50
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Weber MA, Nagel AM, Marschar AM, Glemser P, Jurkat-Rott K, Wolf MB, Ladd ME, Schlemmer HP, Kauczor HU, Lehmann-Horn F. 7-T35Cl and23Na MR Imaging for Detection of Mutation-dependent Alterations in Muscular Edema and Fat Fraction with Sodium and Chloride Concentrations in Muscular Periodic Paralyses. Radiology 2016; 280:848-59. [DOI: 10.1148/radiol.2016151617] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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