1
|
Jędrychowska J, Vardanyan V, Wieczor M, Marciniak A, Czub J, Amini R, Jain R, Shen H, Choi H, Kuznicki J, Korzh V. Mutant analysis of Kcng4b reveals how the different functional states of the voltage-gated potassium channel regulate ear development. Dev Biol 2024; 513:50-62. [PMID: 38492873 DOI: 10.1016/j.ydbio.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/18/2024]
Abstract
The voltage gated (Kv) slow-inactivating delayed rectifier channel regulates the development of hollow organs of the zebrafish. The functional channel consists of the tetramer of electrically active Kcnb1 (Kv2.1) subunits and Kcng4b (Kv6.4) modulatory or electrically silent subunits. The two mutations in zebrafish kcng4b gene - kcng4b-C1 and kcng4b-C2 (Gasanov et al., 2021) - have been studied during ear development using electrophysiology, developmental biology and in silico structural modelling. kcng4b-C1 mutation causes a C-terminal truncation characterized by mild Kcng4b loss-of-function (LOF) manifested by failure of kinocilia to extend and formation of ectopic otoliths. In contrast, the kcng4b-C2-/- mutation causes the C-terminal domain to elongate and the ectopic seventh transmembrane (TM) domain to form, converting the intracellular C-terminus to an extracellular one. Kcng4b-C2 acts as a Kcng4b gain-of-function (GOF) allele. Otoliths fail to develop and kinocilia are reduced in kcng4b-C2-/-. These results show that different mutations of the silent subunit Kcng4 can affect the activity of the Kv channel and cause a wide range of developmental defects.
Collapse
Affiliation(s)
- Justyna Jędrychowska
- International Institute of Molecular and Cell Biology in Warsaw, Poland; Department of Genetics, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
| | - Vitya Vardanyan
- Institute of Molecular Biology, Armenian Academy of Sciences, Yerevan, Armenia
| | - Milosz Wieczor
- Department of Physical Chemistry, Gdansk University of Technology, Gdansk, Poland
| | - Antoni Marciniak
- Department of Physical Chemistry, Gdansk University of Technology, Gdansk, Poland
| | - Jacek Czub
- Department of Physical Chemistry, Gdansk University of Technology, Gdansk, Poland
| | - Razieh Amini
- International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Ruchi Jain
- International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Hongyuan Shen
- Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore
| | - Hyungwon Choi
- Cardiovascular Research Institute, National University Health Sciences, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jacek Kuznicki
- International Institute of Molecular and Cell Biology in Warsaw, Poland
| | - Vladimir Korzh
- International Institute of Molecular and Cell Biology in Warsaw, Poland.
| |
Collapse
|
2
|
Huang S, Hu C, Zhong M, Li Q, Dai Y, Ma J, Qin J, Sun D. Clinical phenotypes of developmental and epileptic encephalopathy-related recurrent KCNH5 missense variant p.R327H in Chinese children. Epilepsy Behav Rep 2024; 26:100671. [PMID: 38708366 PMCID: PMC11068512 DOI: 10.1016/j.ebr.2024.100671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
KCNH5 gene encodes for the voltage-gated potassium channel protein Kv10.2. Here, we investigated the clinical features of developmental and epileptic encephalopathy (DEE) in five Chinese pediatric patients with a missense mutation (p.R327H) in KCNH5 gene. These patients had undergone video EEG to evaluate background features and epileptiform activity, as well as 3.0 T MRI scans for structural analysis and intelligence assessments using the Gesell Developmental Observation or Wechsler Intelligence Scale for Children. Seizure onset occurs between 4 and 10 months of age, with focal and generalized tonic-clonic seizures being common. Initial EEG findings showed multiple multifocal sharp waves, sharp slow waves or spike slow waves, and spike waves. Brain MRI revealed widened extracerebral space in only one patient. Mechanistically, the KCNH5 mutation disrupts the two hydrogen bonds between Arg327 and Asp304 residues, potentially altering the protein's structural stability and function. Almost 80 % of patients receiving add-on valproic acid (VPA) therapy experienced a reduction in epileptic seizure frequency. Altogether, this study presents the first Chinese cohort of pediatric DEE patients with the KCNH5 p.R327H mutation, highlighting focal seizures as the predominant seizure type and incomplete mutation penetrance. Add-on VPA therapy was likely effective in the early stages of DEE pathogenesis.
Collapse
Affiliation(s)
- Sheng Huang
- Department of Neurology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Chunhui Hu
- Department of Neurology, Fujian Children's Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, China
| | - Min Zhong
- Department of Rehabilitation Children’s Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders. Chongqing Key Laboratory of Pediatrics, Chongqing, China
- Laboratory of Translational Medicine Research, Deyang Key Laboratory of Tumor Molecular Research, Deyang, China
| | - Qinrui Li
- Department of Pediatrics, Peking University People’s Hospital, Beijing, China
| | - Yuanyuan Dai
- Department of Pediatrics, Xuzhou Medical University Affiliated Hospital, Xuzhou, China
| | - Jiehui Ma
- Department of Neurology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Jiong Qin
- Department of Pediatrics, Peking University People’s Hospital, Beijing, China
| | - Dan Sun
- Department of Neurology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| |
Collapse
|
3
|
Mosca I, Freri E, Ambrosino P, Belperio G, Granata T, Canafoglia L, Ragona F, Solazzi R, Filareto I, Castellotti B, Messina G, Gellera C, DiFrancesco JC, Soldovieri MV, Taglialatela M. Case report: Marked electroclinical improvement by fluoxetine treatment in a patient with KCNT1-related drug-resistant focal epilepsy. Front Cell Neurosci 2024; 18:1367838. [PMID: 38644974 PMCID: PMC11027738 DOI: 10.3389/fncel.2024.1367838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/11/2024] [Indexed: 04/23/2024] Open
Abstract
Variants in KCNT1 are associated with a wide spectrum of epileptic phenotypes, including epilepsy of infancy with migrating focal seizures (EIMFS), non-EIMFS developmental and epileptic encephalopathies, autosomal dominant or sporadic sleep-related hypermotor epilepsy, and focal epilepsy. Here, we describe a girl affected by drug-resistant focal seizures, developmental delay and behavior disorders, caused by a novel, de novo heterozygous missense KCNT1 variant (c.2809A > G, p.S937G). Functional characterization in transiently transfected Chinese Hamster Ovary (CHO) cells revealed a strong gain-of-function effect determined by the KCNT1 p.S937G variant compared to wild-type, consisting in an increased maximal current density and a hyperpolarizing shift in current activation threshold. Exposure to the antidepressant drug fluoxetine inhibited currents expressed by both wild-type and mutant KCNT1 channels. Treatment of the proband with fluoxetine led to a prolonged electroclinical amelioration, with disappearance of seizures and better EEG background organization, together with an improvement in behavior and mood. Altogether, these results suggest that, based on the proband's genetic and functional characteristics, the antidepressant drug fluoxetine may be repurposed for the treatment of focal epilepsy caused by gain-of-function variants in KCNT1. Further studies are needed to verify whether this approach could be also applied to other phenotypes of the KCNT1-related epilepsies spectrum.
Collapse
Affiliation(s)
- Ilaria Mosca
- Department of Medicine and Health Sciences “Vincenzo Tiberio”, University of Molise, Campobasso, Italy
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Paolo Ambrosino
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Giorgio Belperio
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Laura Canafoglia
- Department of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Roberta Solazzi
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Ilaria Filareto
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Barbara Castellotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Giuliana Messina
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Cinzia Gellera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | | | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences “Vincenzo Tiberio”, University of Molise, Campobasso, Italy
| | | |
Collapse
|
4
|
Zhao X, Ding W, Wang H, Wang Y, Liu Y, Li Y, Liu C. Structural Insights and Influence of Terahertz Waves in Midinfrared Region on Kv1.2 Channel Selectivity Filter. ACS OMEGA 2024; 9:9702-9713. [PMID: 38434859 PMCID: PMC10905694 DOI: 10.1021/acsomega.3c09801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 03/05/2024]
Abstract
Potassium ion channels are the structural basis for excitation transmission, heartbeat, and other biological processes. The selectivity filter is a critical structural component of potassium ion channels, whose structure is crucial to realizing their function. As biomolecules vibrate and rotate at frequencies in the terahertz band, potassium ion channels are sensitive to terahertz waves. Therefore, it is worthwhile to investigate how the terahertz wave influences the selectivity filter of the potassium channels. In this study, we investigate the structure of the selectivity filter of Kv1.2 potassium ion channels using molecular dynamics simulations. The effect of an electric field on the channel has been examined at four different resonant frequencies of the carbonyl group in SF: 36.75 37.06, 37.68, and 38.2 THz. As indicated by the results, 376GLY appears to be the critical residue in the selectivity filter of the Kv1.2 channel. Its dihedral angle torsion is detrimental to the channel structural stability and the transmembrane movement of potassium ions. 36.75 THz is the resonance frequency of the carbonyl group of 376GLY. Among all four frequencies explored, the applied terahertz electric field of this frequency has the most significant impact on the channel structure, negatively impacting the channel stability and reducing the ion permeability by 20.2% compared to the absence of fields. In this study, we simulate that terahertz waves in the mid-infrared frequency region can significantly alter the structure and function of potassium ion channels and that the effects of terahertz waves differ greatly based on frequency.
Collapse
Affiliation(s)
- Xiaofei Zhao
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Wen Ding
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Hongguang Wang
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Yize Wang
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Yanjiang Liu
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Yongdong Li
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Chunliang Liu
- Key Laboratory
for Physical
Electronics and Devices of the Ministry of Education, School of Electronic
and Information Engineering, Xi’an
Jiaotong University, Xi’an, Shaanxi 710049, China
| |
Collapse
|
5
|
Soldovieri MV, Ambrosino P, Mosca I, Servettini I, Pietrunti F, Belperio G, Syrbe S, Taglialatela M, Lemke JR. De novo variants in KCNA3 cause developmental and epileptic encephalopathy. Ann Neurol 2024; 95:365-376. [PMID: 37964487 DOI: 10.1002/ana.26826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 10/06/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023]
Abstract
OBJECTIVE Variants in several potassium channel genes, including KCNA1 and KCNA2, cause Developmental and Epileptic Encephalopathies (DEEs). We investigated whether variants in KCNA3, another mammalian homologue of the Drosophila shaker family and encoding for Kv1.3 subunits, can cause DEE. METHODS Genetic analysis of study individuals was performed by routine exome or genome sequencing, usually of parent-offspring trios. Phenotyping was performed via a standard clinical questionnaire. Currents from wild-type and/or mutant Kv1.3 subunits were investigated by whole-cell patch-clamp upon their heterologous expression. RESULTS Fourteen individuals, each carrying a de novo heterozygous missense variant in KCNA3, were identified. Most (12/14; 86%) had DEE with marked speech delay with or without motor delay, intellectual disability, epilepsy, and autism spectrum disorder. Functional analysis of Kv1.3 channels carrying each variant revealed heterogeneous functional changes, ranging from "pure" loss-of-function (LoF) effects due to faster inactivation kinetics, depolarized voltage-dependence of activation, slower activation kinetics, increased current inactivation, reduced or absent currents with or without dominant-negative effects, to "mixed" loss- and gain-of-function (GoF) effects. Compared to controls, Kv1.3 currents in lymphoblasts from 1 of the proband displayed functional changes similar to those observed upon heterologous expression of channels carrying the same variant. The antidepressant drug fluoxetine inhibited with similar potency the currents from wild-type and 1 of the Kv1.3 GoF variant. INTERPRETATION We describe a novel association of de novo missense variants in KCNA3 with a human DEE, and provide evidence that fluoxetine might represent a potential targeted treatment for individuals carrying variants with significant GoF effects. ANN NEUROL 2024;95:365-376.
Collapse
Affiliation(s)
| | - Paolo Ambrosino
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Ilaria Mosca
- Department of Medicine and Health Science "V. Tiberio", University of Molise, Campobasso, Italy
| | - Ilenio Servettini
- Department of Medicine and Health Science "V. Tiberio", University of Molise, Campobasso, Italy
| | - Francesca Pietrunti
- Department of Medicine and Health Science "V. Tiberio", University of Molise, Campobasso, Italy
| | - Giorgio Belperio
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Steffen Syrbe
- Center for Pediatrics and Adolescent Medicine, Division of Pediatric Epileptology, University Hospital Heidelberg, Heidelberg, Germany
| | - Maurizio Taglialatela
- Department of Neuroscience, Division of Pharmacology, University of Naples "Federico II", Naples, Italy
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| |
Collapse
|
6
|
Proietti J, Fiorini E, Cantalupo G, Fontana E, Lo Barco T, Bonin C, Bernardina BD, Darra F. Refractory tonic-myoclonic status epilepticus with catamenial recurrence in epilepsy with myoclonic atonic seizures: A case report. Heliyon 2024; 10:e24747. [PMID: 38304836 PMCID: PMC10831770 DOI: 10.1016/j.heliyon.2024.e24747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/08/2023] [Accepted: 01/12/2024] [Indexed: 02/03/2024] Open
Abstract
In epilepsy with myoclonic-atonic seizures (EMA), status epilepticus (SE) may occur during the onset phase, uncommonly in post-puberal patients. We report a post-puberal patient with EMA who presented SE with insidious onset and catamenial recurrence. She had a stormy epilepsy onset at 4 years, with tonic seizures, atypical absences, and myoclonic-atonic seizures, in the absence of SE. After the onset phase, sporadic nocturnal tonic seizures persisted and a mild intellectual disability appeared. At the age of 7, after gonadotropin-releasing hormone analog administration due to central precocious puberty, she presented with SE characterized by recurrent atypical absences, tonic seizures, and awareness impairment, which was successfully treated in 4 days. At 11 years, one week before menstruation, the patient presented with analogous SE that lasted 8 days. One week before the subsequent menstruation, she presented again with SE, initially characterized by atypical absences alternating with phases of awareness and motor impairment related to fast low-voltage EEG activity in the central regions; later, tonic and myoclonic seizures occurring even in the awake state increased, and the "atonic-akinetic status" related to fast EEG activity worsened. After conventional antiepileptic drugs had failed to control the seizures, a progestin was added, with subsequent gradual complete recovery.
Collapse
Affiliation(s)
- Jacopo Proietti
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Innovation biomedicine Section, Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Elena Fiorini
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Gaetano Cantalupo
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Innovation biomedicine Section, Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Elena Fontana
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Tommaso Lo Barco
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Cecilia Bonin
- U.O.C. Ostetricia e Ginecologia B, Dipartimento di Ostetricia e Ginecologia, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | | | - Francesca Darra
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata, Verona, Italy - Full member of ERN EpiCARE
- Innovation biomedicine Section, Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| |
Collapse
|
7
|
Khan R, Chaturvedi P, Sahu P, Ludhiadch A, Singh P, Singh G, Munshi A. Role of Potassium Ion Channels in Epilepsy: Focus on Current Therapeutic Strategies. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:67-87. [PMID: 36578258 DOI: 10.2174/1871527322666221227112621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Epilepsy is one of the prevalent neurological disorders characterized by disrupted synchronization between inhibitory and excitatory neurons. Disturbed membrane potential due to abnormal regulation of neurotransmitters and ion transport across the neural cell membrane significantly contributes to the pathophysiology of epilepsy. Potassium ion channels (KCN) regulate the resting membrane potential and are involved in neuronal excitability. Genetic alterations in the potassium ion channels (KCN) have been reported to result in the enhancement of the release of neurotransmitters, the excitability of neurons, and abnormal rapid firing rate, which lead to epileptic phenotypes, making these ion channels a potential therapeutic target for epilepsy. The aim of this study is to explore the variations reported in different classes of potassium ion channels (KCN) in epilepsy patients, their functional evaluation, and therapeutic strategies to treat epilepsy targeting KCN. METHODOLOGY A review of all the relevant literature was carried out to compile this article. RESULTS A large number of variations have been reported in different genes encoding various classes of KCN. These genetic alterations in KCN have been shown to be responsible for disrupted firing properties of neurons. Antiepileptic drugs (AEDs) are the main therapeutic strategy to treat epilepsy. Some patients do not respond favorably to the AEDs treatment, resulting in pharmacoresistant epilepsy. CONCLUSION Further to address the challenges faced in treating epilepsy, recent approaches like optogenetics, chemogenetics, and genome editing, such as clustered regularly interspaced short palindromic repeats (CRISPR), are emerging as target-specific therapeutic strategies.
Collapse
Affiliation(s)
- Rahul Khan
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Pragya Chaturvedi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Prachi Sahu
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Abhilash Ludhiadch
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| | - Paramdeep Singh
- Department of Radiology, All India Institute of Medical Sciences, Bathinda, Punjab, 151001 India
| | - Gagandeep Singh
- Department of Neurology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
| | - Anjana Munshi
- Department of Human Genetics and Molecular Medicine Central University of Punjab, Bathinda 151401, India
| |
Collapse
|
8
|
Soto-Perez J, Cleary CM, Sobrinho CR, Mulkey SB, Carroll JL, Tzingounis AV, Mulkey DK. Phox2b-expressing neurons contribute to breathing problems in Kcnq2 loss- and gain-of-function encephalopathy models. Nat Commun 2023; 14:8059. [PMID: 38052789 PMCID: PMC10698053 DOI: 10.1038/s41467-023-43834-7] [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: 04/20/2023] [Accepted: 11/21/2023] [Indexed: 12/07/2023] Open
Abstract
Loss- and gain-of-function variants in the gene encoding KCNQ2 channels are a common cause of developmental and epileptic encephalopathy, a condition characterized by seizures, developmental delays, breathing problems, and early mortality. To understand how KCNQ2 dysfunction impacts behavior in a mouse model, we focus on the control of breathing by neurons expressing the transcription factor Phox2b which includes respiratory neurons in the ventral parafacial region. We find Phox2b-expressing ventral parafacial neurons express Kcnq2 in the absence of other Kcnq isoforms, thus clarifying why disruption of Kcnq2 but not other channel isoforms results in breathing problems. We also find that Kcnq2 deletion or expression of a recurrent gain-of-function variant R201C in Phox2b-expressing neurons increases baseline breathing or decreases the central chemoreflex, respectively, in mice during the light/inactive state. These results uncover mechanisms underlying breathing abnormalities in KCNQ2 encephalopathy and highlight an unappreciated vulnerability of Phox2b-expressing ventral parafacial neurons to KCNQ2 pathogenic variants.
Collapse
Affiliation(s)
- J Soto-Perez
- Dept of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - C M Cleary
- Dept of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - C R Sobrinho
- Dept of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - S B Mulkey
- Prenatal Pediatrics Institute, Children's National Hospital, Departments of Neurology and Pediatrics, The George Washington Univ. School of Medicine and Health Sciences, Washington, DC, USA
| | - J L Carroll
- Dept. of Pediatrics, Univ. Arkansas for Medical Sciences, Little Rock, AR, USA
| | - A V Tzingounis
- Dept of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.
| | - D K Mulkey
- Dept of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.
| |
Collapse
|
9
|
Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [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: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
Collapse
Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
| | | | | |
Collapse
|
10
|
Bortolami A, Sesti F. Ion channels in neurodevelopment: lessons from the Integrin-KCNB1 channel complex. Neural Regen Res 2023; 18:2365-2369. [PMID: 37282454 PMCID: PMC10360111 DOI: 10.4103/1673-5374.371347] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Ion channels modulate cellular excitability by regulating ionic fluxes across biological membranes. Pathogenic mutations in ion channel genes give rise to epileptic disorders that are among the most frequent neurological diseases affecting millions of individuals worldwide. Epilepsies are triggered by an imbalance between excitatory and inhibitory conductances. However, pathogenic mutations in the same allele can give rise to loss-of-function and/or gain-of-function variants, all able to trigger epilepsy. Furthermore, certain alleles are associated with brain malformations even in the absence of a clear electrical phenotype. This body of evidence argues that the underlying epileptogenic mechanisms of ion channels are more diverse than originally thought. Studies focusing on ion channels in prenatal cortical development have shed light on this apparent paradox. The picture that emerges is that ion channels play crucial roles in landmark neurodevelopmental processes, including neuronal migration, neurite outgrowth, and synapse formation. Thus, pathogenic channel mutants can not only cause epileptic disorders by altering excitability, but further, by inducing morphological and synaptic abnormalities that are initiated during neocortex formation and may persist into the adult brain.
Collapse
Affiliation(s)
- Alessandro Bortolami
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, West Piscataway, NJ, USA
| | - Federico Sesti
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, West Piscataway, NJ, USA
| |
Collapse
|
11
|
Varghese N, Moscoso B, Chavez A, Springer K, Ortiz E, Soh H, Santaniello S, Maheshwari A, Tzingounis AV. KCNQ2/3 Gain-of-Function Variants and Cell Excitability: Differential Effects in CA1 versus L2/3 Pyramidal Neurons. J Neurosci 2023; 43:6479-6494. [PMID: 37607817 PMCID: PMC10513074 DOI: 10.1523/jneurosci.0980-23.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/24/2023] Open
Abstract
Gain-of-function (GOF) pathogenic variants in the potassium channels KCNQ2 and KCNQ3 lead to hyperexcitability disorders such as epilepsy and autism spectrum disorders. However, the underlying cellular mechanisms of how these variants impair forebrain function are unclear. Here, we show that the R201C variant in KCNQ2 has opposite effects on the excitability of two types of mouse pyramidal neurons of either sex, causing hyperexcitability in layer 2/3 (L2/3) pyramidal neurons and hypoexcitability in CA1 pyramidal neurons. Similarly, the homologous R231C variant in KCNQ3 leads to hyperexcitability in L2/3 pyramidal neurons and hypoexcitability in CA1 pyramidal neurons. However, the effects of KCNQ3 gain-of-function on excitability are specific to superficial CA1 pyramidal neurons. These findings reveal a new level of complexity in the function of KCNQ2 and KCNQ3 channels in the forebrain and provide a framework for understanding the effects of gain-of-function variants and potassium channels in the brain.SIGNIFICANCE STATEMENT KCNQ2/3 gain-of-function (GOF) variants lead to severe forms of neurodevelopmental disorders, but the mechanisms by which these channels affect neuronal activity are poorly understood. In this study, using a series of transgenic mice we demonstrate that the same KCNQ2/3 GOF variants can lead to either hyperexcitability or hypoexcitability in different types of pyramidal neurons [CA1 vs layer (L)2/3]. Additionally, we show that expression of the recurrent KCNQ2 GOF variant R201C in forebrain pyramidal neurons could lead to seizures and SUDEP. Our data suggest that the effects of KCNQ2/3 GOF variants depend on specific cell types and brain regions, possibly accounting for the diverse range of phenotypes observed in individuals with KCNQ2/3 GOF variants.
Collapse
Affiliation(s)
- Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Bruno Moscoso
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Ana Chavez
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Erika Ortiz
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Sabato Santaniello
- Department of Biomedical Engineering and Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut 06269
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, Houston, Texas 77030
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| |
Collapse
|
12
|
Borges FS, Protachevicz PR, Souza DLM, Bittencourt CF, Gabrick EC, Bentivoglio LE, Szezech JD, Batista AM, Caldas IL, Dura-Bernal S, Pena RFO. The Roles of Potassium and Calcium Currents in the Bistable Firing Transition. Brain Sci 2023; 13:1347. [PMID: 37759949 PMCID: PMC10527161 DOI: 10.3390/brainsci13091347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Healthy brains display a wide range of firing patterns, from synchronized oscillations during slow-wave sleep to desynchronized firing during movement. These physiological activities coexist with periods of pathological hyperactivity in the epileptic brain, where neurons can fire in synchronized bursts. Most cortical neurons are pyramidal regular spiking (RS) cells with frequency adaptation and do not exhibit bursts in current-clamp experiments (in vitro). In this work, we investigate the transition mechanism of spike-to-burst patterns due to slow potassium and calcium currents, considering a conductance-based model of a cortical RS cell. The joint influence of potassium and calcium ion channels on high synchronous patterns is investigated for different synaptic couplings (gsyn) and external current inputs (I). Our results suggest that slow potassium currents play an important role in the emergence of high-synchronous activities, as well as in the spike-to-burst firing pattern transitions. This transition is related to the bistable dynamics of the neuronal network, where physiological asynchronous states coexist with pathological burst synchronization. The hysteresis curve of the coefficient of variation of the inter-spike interval demonstrates that a burst can be initiated by firing states with neuronal synchronization. Furthermore, we notice that high-threshold (IL) and low-threshold (IT) ion channels play a role in increasing and decreasing the parameter conditions (gsyn and I) in which bistable dynamics occur, respectively. For high values of IL conductance, a synchronous burst appears when neurons are weakly coupled and receive more external input. On the other hand, when the conductance IT increases, higher coupling and lower I are necessary to produce burst synchronization. In light of our results, we suggest that channel subtype-specific pharmacological interactions can be useful to induce transitions from pathological high bursting states to healthy states.
Collapse
Affiliation(s)
- Fernando S. Borges
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Center for Mathematics, Computation and Cognition, Federal University of ABC, São Bernardo do Campo 09606-045, Brazil
| | | | - Diogo L. M. Souza
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
| | - Conrado F. Bittencourt
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
| | - Enrique C. Gabrick
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
| | - Lucas E. Bentivoglio
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
| | - José D. Szezech
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
- Department of Mathematics and Statistics, State University of Ponta Grossa, Ponta Grossa 84030-900, Brazil
| | - Antonio M. Batista
- Graduate Program in Science, State University of Ponta Grossa, Ponta Grossa 84010-330, Brazil
- Department of Mathematics and Statistics, State University of Ponta Grossa, Ponta Grossa 84030-900, Brazil
| | - Iberê L. Caldas
- Institute of Physics, University of São Paulo, São Paulo 05508-090, Brazil
| | - Salvador Dura-Bernal
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Center for Biomedical Imaging and Neuromodulation, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Rodrigo F. O. Pena
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, USA
| |
Collapse
|
13
|
Cioclu MC, Mosca I, Ambrosino P, Puzo D, Bayat A, Wortmann SB, Koch J, Strehlow V, Shirai K, Matsumoto N, Sanders SJ, Michaud V, Legendre M, Riva A, Striano P, Muhle H, Pendziwiat M, Lesca G, Mangano GD, Nardello R, Lemke JR, Møller RS, Soldovieri MV, Rubboli G, Taglialatela M. KCNT2-Related Disorders: Phenotypes, Functional, and Pharmacological Properties. Ann Neurol 2023; 94:332-349. [PMID: 37062836 DOI: 10.1002/ana.26662] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 04/10/2023] [Accepted: 04/14/2023] [Indexed: 04/18/2023]
Abstract
OBJECTIVE Pathogenic variants in KCNT2 are rare causes of developmental epileptic encephalopathy (DEE). We herein describe the phenotypic and genetic features of patients with KCNT2-related DEE, and the in vitro functional and pharmacological properties of KCNT2 channels carrying 14 novel or previously untested variants. METHODS Twenty-five patients harboring KCNT2 variants were investigated: 12 were identified through an international collaborative network, 13 were retrieved from the literature. Clinical data were collected and included in a standardized phenotyping sheet. Novel variants were detected using exome sequencing and classified using ACMG criteria. Functional and pharmacological studies were performed by whole-cell electrophysiology in HEK-293 and SH-SY5Y cells. RESULTS The phenotypic spectrum encompassed: (a) intellectual disability/developmental delay (21/22 individuals with available information), ranging from mild to severe/profound; (b) epilepsy (15/25); (c) neurological impairment, with altered muscle tone (14/22); (d) dysmorphisms (13/20). Nineteen pathogenic KCNT2 variants were found (9 new, 10 reported previously): 16 missense, 1 in-frame deletion of a single amino acid, 1 nonsense, and 1 frameshift. Among tested variants, 8 showed gain-of-function (GoF), and 6 loss-of-function (LoF) features when expressed heterologously in vitro. Quinidine and fluoxetine blocked all GoF variants, whereas loxapine and riluzole activated some LoF variants while blocking others. INTERPRETATION We expanded the phenotypic and genotypic spectrum of KCNT2-related disorders, highlighting novel genotype-phenotype associations. Pathogenic KCNT2 variants cause GoF or LoF in vitro phenotypes, and each shows a unique pharmacological profile, suggesting the need for in vitro functional and pharmacological investigation to enable targeted therapies based on the molecular phenotype. ANN NEUROL 2023;94:332-349.
Collapse
Affiliation(s)
- Maria Cristina Cioclu
- Department of Epilepsy Genetics and Personalized Medicine (member of ERN EpiCARE), Danish Epilepsy Centre, Dianalund, Denmark
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Ilaria Mosca
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Paolo Ambrosino
- Dept. of Science and Technology, University of Sannio, Benevento, Italy
| | - Deborah Puzo
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Allan Bayat
- Department of Epilepsy Genetics and Personalized Medicine (member of ERN EpiCARE), Danish Epilepsy Centre, Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria
- Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Johannes Koch
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Vincent Strehlow
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Kentaro Shirai
- Department of Pediatrics, Tsuchiura Kyodo General Hospital, Tsuchiura, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Stephan J Sanders
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
- Institute for Human Genetics, University of California, San Francisco, CA, USA
- Bakar Computational Health Sciences Institute, University of California, San Francisco, CA, USA
| | - Vincent Michaud
- Service de Génétique Médicale, Centre de Référence Anomalies du Développement et Syndrome Malformatifs, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
- Maladies rares: Génétique et Métabolisme (MRGM), INSERM U1211, Université de Bordeaux, Bordeaux, France
| | - Marine Legendre
- Service de Génétique Médicale, Centre de Référence Anomalies du Développement et Syndrome Malformatifs, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - Antonella Riva
- IRCCS Istituto Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Pasquale Striano
- IRCCS Istituto Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Hiltrud Muhle
- Department of Neuropediatrics, University Medical Centre Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany
| | - Manuela Pendziwiat
- Department of Neuropediatrics, University Medical Centre Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Gaetan Lesca
- Pathophysiology and Genetics of Neuron and Muscle (PNMG), UCBL, CNRS UMR5261-INSERM U1315, Lyon, France
- Department of Medical Genetics, University Hospital of Lyon and Claude Bernard Lyon I University, Lyon, France
| | - Giuseppe Donato Mangano
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, Palermo, Italy
| | - Rosaria Nardello
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties "G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine (member of ERN EpiCARE), Danish Epilepsy Centre, Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Medicine (member of ERN EpiCARE), Danish Epilepsy Centre, Dianalund, Denmark
- University of Copenhagen, Copenhagen, Denmark
| | | |
Collapse
|
14
|
Zhao X, Ding W, Wang H, Wang Y, Liu Y, Li Y, Liu C. Permeability enhancement of Kv1.2 potassium channel by a terahertz electromagnetic field. J Chem Phys 2023; 159:045101. [PMID: 37486058 DOI: 10.1063/5.0143648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/03/2023] [Indexed: 07/25/2023] Open
Abstract
As biomolecules vibrate and rotate in the terahertz band, the biological effects of terahertz electromagnetic fields have drawn considerable attention from the physiological and medical communities. Ion channels are the basis of biological electrical signals, so studying the effect of terahertz electromagnetic fields on ion channels is significant. In this paper, the effect of a terahertz electromagnetic field with three different frequencies, 6, 15, and 25 THz, on the Kv1.2 potassium ion channel was investigated by molecular dynamics simulations. The results show that an electromagnetic field with a 15 THz frequency can significantly enhance the permeability of the Kv1.2 potassium ion channel, which is 1.7 times higher than without an applied electric field. By analyzing the behavior of water molecules, it is found that the electromagnetic field with the 15 THz frequency shortens the duration of frozen and relaxation processes when potassium ions pass through the channel, increases the proportion of the direct knock-on mode, and, thus, enhances the permeability of the Kv1.2 potassium ion channel.
Collapse
Affiliation(s)
- Xiaofei Zhao
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Wen Ding
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Hongguang Wang
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Yize Wang
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Yanjiang Liu
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Yongdong Li
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Chunliang Liu
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| |
Collapse
|
15
|
Rashno Z, Rismani E, Ghasemi JB, Mansouri M, Shabani M, Afgar A, Dabiri S, Rezaei Makhouri F, Hatami A, Harandi MF. Design of ion channel blocking, toxin-like Kunitz inhibitor peptides from the tapeworm, Echinococcus granulosus, with potential anti-cancer activity. Sci Rep 2023; 13:11465. [PMID: 37454225 PMCID: PMC10349847 DOI: 10.1038/s41598-023-38159-w] [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: 12/23/2022] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Over-expression of K+ channels has been reported in human cancers and is associated with the poor prognosis of several malignancies. EAG1, a particular potassium ion channel, is widely expressed in the brain but poorly expressed in other normal tissues. Kunitz proteins are dominant in metazoan including the dog tapeworm, Echinococcus granulosus. Using computational analyses on one A-type potassium channel, EAG1, and in vitro cellular methods, including major cancer cell biomarkers expression, immunocytochemistry and whole-cell patch clamp, we demonstrated the anti-tumor activity of three synthetic small peptides derived from E. granulosus Kunitz4 protease inhibitors. Experiments showed induced significant apoptosis and inhibition of proliferation in both cancer cell lines via disruption in cell-cycle transition from the G0/G1 to S phase. Western blotting showed that the levels of cell cycle-related proteins including P27 and P53 were altered upon kunitz4-a and kunitz4-c treatment. Patch clamp analysis demonstrated a significant increase in spontaneous firing frequency in Purkinje neurons, and exposure to kunitz4-c was associated with an increase in the number of rebound action potentials after hyperpolarized current. This noteworthy component in nature could act as an ion channel blocker and is a potential candidate for cancer chemotherapy based on potassium channel blockage.
Collapse
Affiliation(s)
- Zahra Rashno
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, 7616914115, Iran
| | - Elham Rismani
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Jahan B Ghasemi
- Faculty of Chemistry, School of Sciences, University of Tehran, Tehran, Iran
| | - Mehdi Mansouri
- Department of Agricultural Biotechnology, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Mohammad Shabani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Ali Afgar
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, 7616914115, Iran
| | - Shahriar Dabiri
- Pathology and Stem Cell Research Center, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | | | - Abbas Hatami
- Pathology and Stem Cell Research Center, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Majid Fasihi Harandi
- Research Center for Hydatid Disease in Iran, Afzalipour School of Medicine, Kerman University of Medical Sciences, Kerman, 7616914115, Iran.
| |
Collapse
|
16
|
Koch NA, Sonnenberg L, Hedrich UBS, Lauxmann S, Benda J. Loss or gain of function? Effects of ion channel mutations on neuronal firing depend on the neuron type. Front Neurol 2023; 14:1194811. [PMID: 37292138 PMCID: PMC10244640 DOI: 10.3389/fneur.2023.1194811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Introduction Clinically relevant mutations to voltage-gated ion channels, called channelopathies, alter ion channel function, properties of ionic currents, and neuronal firing. The effects of ion channel mutations are routinely assessed and characterized as loss of function (LOF) or gain of function (GOF) at the level of ionic currents. However, emerging personalized medicine approaches based on LOF/GOF characterization have limited therapeutic success. Potential reasons are among others that the translation from this binary characterization to neuronal firing is currently not well-understood-especially when considering different neuronal cell types. In this study, we investigate the impact of neuronal cell type on the firing outcome of ion channel mutations. Methods To this end, we simulated a diverse collection of single-compartment, conductance-based neuron models that differed in their composition of ionic currents. We systematically analyzed the effects of changes in ion current properties on firing in different neuronal types. Additionally, we simulated the effects of known mutations in KCNA1 gene encoding the KV1.1 potassium channel subtype associated with episodic ataxia type 1 (EA1). Results These simulations revealed that the outcome of a given change in ion channel properties on neuronal excitability depends on neuron type, i.e., the properties and expression levels of the unaffected ionic currents. Discussion Consequently, neuron-type specific effects are vital to a full understanding of the effects of channelopathies on neuronal excitability and are an important step toward improving the efficacy and precision of personalized medicine approaches.
Collapse
Affiliation(s)
- Nils A. Koch
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Ulrike B. S. Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| |
Collapse
|
17
|
Paulhus K, Glasscock E. Novel Genetic Variants Expand the Functional, Molecular, and Pathological Diversity of KCNA1 Channelopathy. Int J Mol Sci 2023; 24:8826. [PMID: 37240170 PMCID: PMC10219020 DOI: 10.3390/ijms24108826] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023] Open
Abstract
The KCNA1 gene encodes Kv1.1 voltage-gated potassium channel α subunits, which are crucial for maintaining healthy neuronal firing and preventing hyperexcitability. Mutations in the KCNA1 gene can cause several neurological diseases and symptoms, such as episodic ataxia type 1 (EA1) and epilepsy, which may occur alone or in combination, making it challenging to establish simple genotype-phenotype correlations. Previous analyses of human KCNA1 variants have shown that epilepsy-linked mutations tend to cluster in regions critical for the channel's pore, whereas EA1-associated mutations are evenly distributed across the length of the protein. In this review, we examine 17 recently discovered pathogenic or likely pathogenic KCNA1 variants to gain new insights into the molecular genetic basis of KCNA1 channelopathy. We provide the first systematic breakdown of disease rates for KCNA1 variants in different protein domains, uncovering potential location biases that influence genotype-phenotype correlations. Our examination of the new mutations strengthens the proposed link between the pore region and epilepsy and reveals new connections between epilepsy-related variants, genetic modifiers, and respiratory dysfunction. Additionally, the new variants include the first two gain-of-function mutations ever discovered for KCNA1, the first frameshift mutation, and the first mutations located in the cytoplasmic N-terminal domain, broadening the functional and molecular scope of KCNA1 channelopathy. Moreover, the recently identified variants highlight emerging links between KCNA1 and musculoskeletal abnormalities and nystagmus, conditions not typically associated with KCNA1. These findings improve our understanding of KCNA1 channelopathy and promise to enhance personalized diagnosis and treatment for individuals with KCNA1-linked disorders.
Collapse
Affiliation(s)
| | - Edward Glasscock
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA;
| |
Collapse
|
18
|
Younes S, Mourad N, Salla M, Rahal M, Hammoudi Halat D. Potassium Ion Channels in Glioma: From Basic Knowledge into Therapeutic Applications. MEMBRANES 2023; 13:434. [PMID: 37103862 PMCID: PMC10144598 DOI: 10.3390/membranes13040434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
Ion channels, specifically those controlling the flux of potassium across cell membranes, have recently been shown to exhibit an important role in the pathophysiology of glioma, the most common primary central nervous system tumor with a poor prognosis. Potassium channels are grouped into four subfamilies differing by their domain structure, gating mechanisms, and functions. Pertinent literature indicates the vital functions of potassium channels in many aspects of glioma carcinogenesis, including proliferation, migration, and apoptosis. The dysfunction of potassium channels can result in pro-proliferative signals that are highly related to calcium signaling as well. Moreover, this dysfunction can feed into migration and metastasis, most likely by increasing the osmotic pressure of cells allowing the cells to initiate the "escape" and "invasion" of capillaries. Reducing the expression or channel blockage has shown efficacy in reducing the proliferation and infiltration of glioma cells as well as inducing apoptosis, priming several approaches to target potassium channels in gliomas pharmacologically. This review summarizes the current knowledge on potassium channels, their contribution to oncogenic transformations in glioma, and the existing perspectives on utilizing them as potential targets for therapy.
Collapse
Affiliation(s)
- Samar Younes
- Department of Biomedical Sciences, School of Pharmacy, Lebanese International University, Bekaa 146404, Lebanon
- Institut National de Santé Publique, d’Épidémiologie Clinique et de Toxicologie-Liban (INSPECT-LB), Beirut 1103, Lebanon;
| | - Nisreen Mourad
- Institut National de Santé Publique, d’Épidémiologie Clinique et de Toxicologie-Liban (INSPECT-LB), Beirut 1103, Lebanon;
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Bekaa 146404, Lebanon; (M.R.)
| | - Mohamed Salla
- Department of Biological and Chemical Sciences, School of Arts and Sciences, Lebanese International University, Bekaa 146404, Lebanon;
| | - Mohamad Rahal
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Bekaa 146404, Lebanon; (M.R.)
| | - Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Bekaa 146404, Lebanon; (M.R.)
- Academic Quality Department, QU Health, Qatar University, Doha 2713, Qatar;
| |
Collapse
|
19
|
Happ HC, Sadleir LG, Zemel M, de Valles-Ibáñez G, Hildebrand MS, McConkie-Rosell A, McDonald M, May H, Sands T, Aggarwal V, Elder C, Feyma T, Bayat A, Møller RS, Fenger CD, Klint Nielsen JE, Datta AN, Gorman KM, King MD, Linhares ND, Burton BK, Paras A, Ellard S, Rankin J, Shukla A, Majethia P, Olson RJ, Muthusamy K, Schimmenti LA, Starnes K, Sedláčková L, Štěrbová K, Vlčková M, Laššuthová P, Jahodová A, Porter BE, Couque N, Colin E, Prouteau C, Collet C, Smol T, Caumes R, Vansenne F, Bisulli F, Licchetta L, Person R, Torti E, McWalter K, Webster R, Gerard EE, Lesca G, Szepetowski P, Scheffer IE, Mefford HC, Carvill GL. Neurodevelopmental and Epilepsy Phenotypes in Individuals With Missense Variants in the Voltage-Sensing and Pore Domains of KCNH5. Neurology 2023; 100:e603-e615. [PMID: 36307226 PMCID: PMC9946193 DOI: 10.1212/wnl.0000000000201492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/14/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES KCNH5 encodes the voltage-gated potassium channel EAG2/Kv10.2. We aimed to delineate the neurodevelopmental and epilepsy phenotypic spectrum associated with de novo KCNH5 variants. METHODS We screened 893 individuals with developmental and epileptic encephalopathies for KCNH5 variants using targeted or exome sequencing. Additional individuals with KCNH5 variants were identified through an international collaboration. Clinical history, EEG, and imaging data were analyzed; seizure types and epilepsy syndromes were classified. We included 3 previously published individuals including additional phenotypic details. RESULTS We report a cohort of 17 patients, including 9 with a recurrent de novo missense variant p.Arg327His, 4 with a recurrent missense variant p.Arg333His, and 4 additional novel missense variants. All variants were located in or near the functionally critical voltage-sensing or pore domains, absent in the general population, and classified as pathogenic or likely pathogenic using the American College of Medical Genetics and Genomics criteria. All individuals presented with epilepsy with a median seizure onset at 6 months. They had a wide range of seizure types, including focal and generalized seizures. Cognitive outcomes ranged from normal intellect to profound impairment. Individuals with the recurrent p.Arg333His variant had a self-limited drug-responsive focal or generalized epilepsy and normal intellect, whereas the recurrent p.Arg327His variant was associated with infantile-onset DEE. Two individuals with variants in the pore domain were more severely affected, with a neonatal-onset movement disorder, early-infantile DEE, profound disability, and childhood death. DISCUSSION We describe a cohort of 17 individuals with pathogenic or likely pathogenic missense variants in the voltage-sensing and pore domains of Kv10.2, including 14 previously unreported individuals. We present evidence for a putative emerging genotype-phenotype correlation with a spectrum of epilepsy and cognitive outcomes. Overall, we expand the role of EAG proteins in human disease and establish KCNH5 as implicated in a spectrum of neurodevelopmental disorders and epilepsy.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Heather C. Mefford
- From the Ken and Ruth Davee Department of Neurology (K.C.H., E.E.G., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL; University of Otago (L.G.S.), Wellington, New Zealand; University of Washington (M.Z.), Seattle; Department of Medicine (G.d.V.-I., R.W., I.E.S.), Epilepsy Research Centre, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; Duke University Medical Center (A.M.-R., M.M.), Durham, NC; Institute for Genomic Medicine (H.M., T.S.), Columbia University Irving Medical Center, New York, NY; Departments of Pathology and Cell Biology (V.A.), and Neurology (C.E.), Columbia University Irving Medical Center, New York, NY; Gillette Children's Specialty Healthcare (T.F.), St. Paul, MN; Department of Epilepsy Genetics and Personalized Medicine (A.B., R.S.M., C.D.F.), Danish Epilepsy Center, Dianalund, Denmark; Institute of Regional Health Research (A.B., R.S.M.), University of Southern Denmark; Amplexa Genetics (C.D.F.), Odense, Denmark; Department of Clinical Medicine (J.E.K.N.), Zealand University Hospital, Roskilde, Denmark; University of British Columbia (A.N.D.), Vancouver, Canada; The Department of Neurology and Clinical Neurophysiology (K.M.G., M.D.K.), Children's Health Ireland at Temple St., Dublin 1, Ireland; School of Medicine and Medical Science (K.M.G., M.D.K.), University College Dublin, Ireland; Genuity Science (N.L.), Dublin, Ireland; Ann & Robert H. Lurie Children's Hospital of Chicago (B.K.B., A.P.), Chicago, IL; Department of Pediatrics (B.K.B., A.P., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL; Exeter Genomics Laboratory (S.E.), Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom; Institute of Clinical and Biomedical Science (S.E.), University of Exeter, United Kingdom; Department Clinical Genetics (J.R.), Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom; Department of Medical Genetics (A.S., P.M.), Kasturba Medical College, Manipal, Manipal Academy of Higher Education, India; Center for Individualized Medicine (R.J.O., K.M., L.A.S.), Mayo Clinic, Rochester, MN; Departments of Clinical Genomics (K.M., L.A.S.), and Neurology (K.S.), Mayo Clinic, Rochester, MN; Neurogenetic Laboratory (L.S., P.J.), Department of Pediatric Neurology, Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Epilepsy Research Centre Prague—EpiReC Consortium (L.S., K.S., M.V., P.L., A.J.); Motol University Hospital is a full member of the ERN EpiCARE; Department of Pediatric Neurology (K.S., A.J.), Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Biology and Medical Genetics (M.V.), Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Stanford University School of Medicine (B.E.P.), Palo Alto, CA; Laboratoire de Biologie médicale multisites Seqoia-FMG2025 (N.C., C.C.), Laboratoire Génétique Moléculaire Robert-Debré, Paris, France; Service de Génétique (E.C., C.P.), CHU d'Angers, Angers, France; University Lille (T.S.), CHU Lille, ULR7364—RADEME, Institut de Genetique Medicale, France; University Lille (R.C.), CHU Lille, ULR7364—RADEME, Clinique de Genetique, France; Univeristy Medical Center Groningen (F.V.), Groningen, the Netherlands; Department of Biomedical and NeuroMotor Sciences (F.B.), University of Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna (F.B., L.L.), Full Member of the ERN EpiCARE Bologna, Italy; GeneDx (R.P., E.T., K.M.), Gaithersburg, MD; T.Y. Nelson Department of Neurology and Neurosurgery (R.W.), Children's Hospital at Westmead, Westmead, New South Wales, Australia; Department of Medical Genetics (G.L.), University Hospital of Lyon, Claude Bernard Lyon 1 University, France; INSERM, Aix-Marseille University (P.S.), INMED, France; Department of Neurology (I.E.S.), Royal Children's Hospital, Department of Paediatrics, The University of Melbourne, and Murdoch Children's Research Institute, Parkville, Victoria, Australia; The Florey Institute of Neuroscience and Mental Health (I.E.S.), Victoria, Australia; Center for Pediatric Neurological Disease Research (H.C.M.), St. Jude Children's Research Hospital, Memphis, TN; and Department of Pharmacology (G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Gemma L. Carvill
- From the Ken and Ruth Davee Department of Neurology (K.C.H., E.E.G., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL; University of Otago (L.G.S.), Wellington, New Zealand; University of Washington (M.Z.), Seattle; Department of Medicine (G.d.V.-I., R.W., I.E.S.), Epilepsy Research Centre, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; Duke University Medical Center (A.M.-R., M.M.), Durham, NC; Institute for Genomic Medicine (H.M., T.S.), Columbia University Irving Medical Center, New York, NY; Departments of Pathology and Cell Biology (V.A.), and Neurology (C.E.), Columbia University Irving Medical Center, New York, NY; Gillette Children's Specialty Healthcare (T.F.), St. Paul, MN; Department of Epilepsy Genetics and Personalized Medicine (A.B., R.S.M., C.D.F.), Danish Epilepsy Center, Dianalund, Denmark; Institute of Regional Health Research (A.B., R.S.M.), University of Southern Denmark; Amplexa Genetics (C.D.F.), Odense, Denmark; Department of Clinical Medicine (J.E.K.N.), Zealand University Hospital, Roskilde, Denmark; University of British Columbia (A.N.D.), Vancouver, Canada; The Department of Neurology and Clinical Neurophysiology (K.M.G., M.D.K.), Children's Health Ireland at Temple St., Dublin 1, Ireland; School of Medicine and Medical Science (K.M.G., M.D.K.), University College Dublin, Ireland; Genuity Science (N.L.), Dublin, Ireland; Ann & Robert H. Lurie Children's Hospital of Chicago (B.K.B., A.P.), Chicago, IL; Department of Pediatrics (B.K.B., A.P., G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL; Exeter Genomics Laboratory (S.E.), Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom; Institute of Clinical and Biomedical Science (S.E.), University of Exeter, United Kingdom; Department Clinical Genetics (J.R.), Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom; Department of Medical Genetics (A.S., P.M.), Kasturba Medical College, Manipal, Manipal Academy of Higher Education, India; Center for Individualized Medicine (R.J.O., K.M., L.A.S.), Mayo Clinic, Rochester, MN; Departments of Clinical Genomics (K.M., L.A.S.), and Neurology (K.S.), Mayo Clinic, Rochester, MN; Neurogenetic Laboratory (L.S., P.J.), Department of Pediatric Neurology, Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Epilepsy Research Centre Prague—EpiReC Consortium (L.S., K.S., M.V., P.L., A.J.); Motol University Hospital is a full member of the ERN EpiCARE; Department of Pediatric Neurology (K.S., A.J.), Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Biology and Medical Genetics (M.V.), Second Faculty of Medicine, Charles University in Prague and Motol University Hospital, Czech Republic; Stanford University School of Medicine (B.E.P.), Palo Alto, CA; Laboratoire de Biologie médicale multisites Seqoia-FMG2025 (N.C., C.C.), Laboratoire Génétique Moléculaire Robert-Debré, Paris, France; Service de Génétique (E.C., C.P.), CHU d'Angers, Angers, France; University Lille (T.S.), CHU Lille, ULR7364—RADEME, Institut de Genetique Medicale, France; University Lille (R.C.), CHU Lille, ULR7364—RADEME, Clinique de Genetique, France; Univeristy Medical Center Groningen (F.V.), Groningen, the Netherlands; Department of Biomedical and NeuroMotor Sciences (F.B.), University of Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna (F.B., L.L.), Full Member of the ERN EpiCARE Bologna, Italy; GeneDx (R.P., E.T., K.M.), Gaithersburg, MD; T.Y. Nelson Department of Neurology and Neurosurgery (R.W.), Children's Hospital at Westmead, Westmead, New South Wales, Australia; Department of Medical Genetics (G.L.), University Hospital of Lyon, Claude Bernard Lyon 1 University, France; INSERM, Aix-Marseille University (P.S.), INMED, France; Department of Neurology (I.E.S.), Royal Children's Hospital, Department of Paediatrics, The University of Melbourne, and Murdoch Children's Research Institute, Parkville, Victoria, Australia; The Florey Institute of Neuroscience and Mental Health (I.E.S.), Victoria, Australia; Center for Pediatric Neurological Disease Research (H.C.M.), St. Jude Children's Research Hospital, Memphis, TN; and Department of Pharmacology (G.L.C.), Northwestern University Feinberg School of Medicine, Chicago, IL
| |
Collapse
|
20
|
The Role of Zinc in Modulating Acid-Sensing Ion Channel Function. Biomolecules 2023; 13:biom13020229. [PMID: 36830598 PMCID: PMC9953155 DOI: 10.3390/biom13020229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated, voltage-independent sodium channels widely expressed throughout the central and peripheral nervous systems. They are involved in synaptic plasticity, learning/memory, fear conditioning and pain. Zinc, an important trace metal in the body, contributes to numerous physiological functions, with neurotransmission being of note. Zinc has been implicated in the modulation of ASICs by binding to specific sites on these channels and exerting either stimulatory or inhibitory effects depending on the ASIC subtype. ASICs have been linked to several neurological and psychological disorders, such as Alzheimer's disease, Parkinson's disease, ischemic stroke, epilepsy and cocaine addiction. Different ASIC isoforms contribute to the persistence of each of these neurological and psychological disorders. It is critical to understand how various zinc concentrations can modulate specific ASIC subtypes and how zinc regulation of ASICs can contribute to neurological and psychological diseases. This review elucidates zinc's structural interactions with ASICs and discusses the potential therapeutic implications zinc may have on neurological and psychological diseases through targeting ASICs.
Collapse
|
21
|
Li L, Zhang C, Wang Z, Wang Y, Guo Y, Qi C, You G, Zhang Z, Fan X, Jiang T. Development of an integrated predictive model for postoperative glioma-related epilepsy using gene-signature and clinical data. BMC Cancer 2023; 23:42. [PMID: 36631762 PMCID: PMC9835377 DOI: 10.1186/s12885-022-10385-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/30/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND This study aimed to develop an integrated model for predicting the occurrence of postoperative seizures in patients with diffuse high-grade gliomas (DHGGs) using clinical and RNA-seq data. METHODS Patients with DHGGs, who received prophylactic anti-epileptic drugs (AEDs) for three months following surgery, were enrolled into the study. The patients were assigned randomly into training (n = 166) and validation (n = 42) cohorts. Differentially expressed genes (DEGs) were identified based on preoperative glioma-related epilepsy (GRE) history. Least absolute shrinkage and selection operator (LASSO) logistic regression analysis was used to construct a predictive gene-signature for the occurrence of postoperative seizures. The final integrated prediction model was generated using the gene-signature and clinical data. Receiver operating characteristic analysis and calibration curve method were used to evaluate the accuracy of the gene-signature and prediction model using the training and validation cohorts. RESULTS A seven-gene signature for predicting the occurrence of postoperative seizures was developed using LASSO logistic regression analysis of 623 DEGs. The gene-signature showed satisfactory predictive capacity in the training cohort [area under the curve (AUC) = 0.842] and validation cohort (AUC = 0.751). The final integrated prediction model included age, temporal lobe involvement, preoperative GRE history, and gene-signature-derived risk score. The AUCs of the integrated prediction model were 0.878 and 0.845 for the training and validation cohorts, respectively. CONCLUSION We developed an integrated prediction model for the occurrence of postoperative seizures in patients with DHGG using clinical and RNA-Seq data. The findings of this study may contribute to the development of personalized management strategies for patients with DHGGs and improve our understanding of the mechanisms underlying GRE in these patients.
Collapse
Affiliation(s)
- Lianwang Li
- grid.411918.40000 0004 1798 6427Department of Neuro-Oncology and Neurosurgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, 300060 China
| | - Chuanbao Zhang
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Zheng Wang
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Yinyan Wang
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Yuhao Guo
- grid.411617.40000 0004 0642 1244Beijing Neurosurgical Institute, Capital Medical University, Beijing, 100070 China
| | - Chong Qi
- grid.411617.40000 0004 0642 1244Beijing Neurosurgical Institute, Capital Medical University, Beijing, 100070 China
| | - Gan You
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Zhong Zhang
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China
| | - Xing Fan
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China ,grid.411617.40000 0004 0642 1244Beijing Neurosurgical Institute, Capital Medical University, Beijing, 100070 China
| | - Tao Jiang
- grid.411617.40000 0004 0642 1244Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070 China ,grid.411617.40000 0004 0642 1244Beijing Neurosurgical Institute, Capital Medical University, Beijing, 100070 China ,grid.506261.60000 0001 0706 7839Research Units of Accurate Diagnosis and Treatment of Brain Tumors and Translational Medicine, Chinese Academy of Medical Sciences, Beijing, 100730 China
| |
Collapse
|
22
|
Zahra A, Liu R, Han W, Meng H, Wang Q, Wang Y, Campbell SL, Wu J. K Ca-Related Neurological Disorders: Phenotypic Spectrum and Therapeutic Indications. Curr Neuropharmacol 2023; 21:1504-1518. [PMID: 36503451 PMCID: PMC10472807 DOI: 10.2174/1570159x21666221208091805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/21/2022] [Accepted: 07/23/2022] [Indexed: 12/14/2022] Open
Abstract
Although potassium channelopathies have been linked to a wide range of neurological conditions, the underlying pathogenic mechanism is not always clear, and a systematic summary of clinical manifestation is absent. Several neurological disorders have been associated with alterations of calcium-activated potassium channels (KCa channels), such as loss- or gain-of-function mutations, post-transcriptional modification, etc. Here, we outlined the current understanding of the molecular and cellular properties of three subtypes of KCa channels, including big conductance KCa channels (BK), small conductance KCa channels (SK), and the intermediate conductance KCa channels (IK). Next, we comprehensively reviewed the loss- or gain-of-function mutations of each KCa channel and described the corresponding mutation sites in specific diseases to broaden the phenotypic-genotypic spectrum of KCa-related neurological disorders. Moreover, we reviewed the current pharmaceutical strategies targeting KCa channels in KCa-related neurological disorders to provide new directions for drug discovery in anti-seizure medication.
Collapse
Affiliation(s)
- Aqeela Zahra
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
- Department of Zoology, University of Sialkot, Sialkot 51310, Pakistan
| | - Ru Liu
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100070, China
- National Clinical Research Center for Neurological Diseases, Beijing 100070, China
| | - Wenzhe Han
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Hui Meng
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Qun Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- National Clinical Research Center for Neurological Diseases, Beijing 100070, China
| | - YunFu Wang
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Susan L. Campbell
- Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Jianping Wu
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
- Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100070, China
- National Clinical Research Center for Neurological Diseases, Beijing 100070, China
| |
Collapse
|
23
|
Gribkoff VK, Kaczmarek LK. The Difficult Path to the Discovery of Novel Treatments in Psychiatric Disorders. ADVANCES IN NEUROBIOLOGY 2023; 30:255-285. [PMID: 36928854 PMCID: PMC10599454 DOI: 10.1007/978-3-031-21054-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
CNS diseases, including psychiatric disorders, represent a significant opportunity for the discovery and development of new drugs and therapeutic treatments with the potential to have a significant impact on human health. CNS diseases, however, present particular challenges to therapeutic discovery efforts, and psychiatric diseases/disorders may be among the most difficult. With specific exceptions such as psychostimulants for ADHD, a large number of psychiatric patients are resistant to existing treatments. In addition, clinicians have no way of knowing which psychiatric patients will respond to which drugs. By definition, psychiatric diagnoses are syndromal in nature; determinations of efficacy are often self-reported, and drug discovery is largely model-based. While such models of psychiatric disease are amenable to screening for new drugs, whether cellular or whole-animal based, they have only modest face validity and, more importantly, predictive validity. Multiple academic, pharmaceutical industry, and government agencies are dedicated to the translation of new findings about the neurobiology of major psychiatric disorders into the discovery and advancement of novel therapies. The collaboration of these agencies provide a pathway for developing new therapeutics. These efforts will be greatly helped by recent advances in understanding the genetic bases of psychiatric disorders, the ongoing search for diagnostic and therapy-responsive biomarkers, and the validation of new animal models.
Collapse
Affiliation(s)
- Valentin K Gribkoff
- Department of Internal Medicine, Section on Endocrinology, Yale University School of Medicine, New Haven, CT, USA.
| | - Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
| |
Collapse
|
24
|
Mulkey DK, Milla BM. Perspectives on the basis of seizure-induced respiratory dysfunction. Front Neural Circuits 2022; 16:1033756. [PMID: 36605420 PMCID: PMC9807672 DOI: 10.3389/fncir.2022.1033756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Epilepsy is an umbrella term used to define a wide variety of seizure disorders and sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in epilepsy. Although some SUDEP risk factors have been identified, it remains largely unpredictable, and underlying mechanisms remain poorly understood. Most seizures start in the cortex, but the high mortality rate associated with certain types of epilepsy indicates brainstem involvement. Therefore, to help understand SUDEP we discuss mechanisms by which seizure activity propagates to the brainstem. Specifically, we highlight clinical and pre-clinical evidence suggesting how seizure activation of: (i) descending inhibitory drive or (ii) spreading depolarization might contribute to brainstem dysfunction. Furthermore, since epilepsy is a highly heterogenous disorder, we also considered factors expected to favor or oppose mechanisms of seizure propagation. We also consider whether epilepsy-associated genetic variants directly impact brainstem function. Because respiratory failure is a leading cause of SUDEP, our discussion of brainstem dysfunction focuses on respiratory control.
Collapse
Affiliation(s)
- Daniel K. Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | | |
Collapse
|
25
|
Rychkov GY, Shaukat Z, Lim CX, Hussain R, Roberts BJ, Bonardi CM, Rubboli G, Meaney BF, Whitney R, Møller RS, Ricos MG, Dibbens LM. Functional Effects of Epilepsy Associated KCNT1 Mutations Suggest Pathogenesis via Aberrant Inhibitory Neuronal Activity. Int J Mol Sci 2022; 23:ijms232315133. [PMID: 36499459 PMCID: PMC9740882 DOI: 10.3390/ijms232315133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
KCNT1 (K+ channel subfamily T member 1) is a sodium-activated potassium channel highly expressed in the nervous system which regulates neuronal excitability by contributing to the resting membrane potential and hyperpolarisation following a train of action potentials. Gain of function mutations in the KCNT1 gene are the cause of neurological disorders associated with different forms of epilepsy. To gain insights into the underlying pathobiology we investigated the functional effects of 9 recently published KCNT1 mutations, 4 previously studied KCNT1 mutations, and one previously unpublished KCNT1 variant of unknown significance. We analysed the properties of KCNT1 potassium currents and attempted to find a correlation between the changes in KCNT1 characteristics due to the mutations and severity of the neurological disorder they cause. KCNT1 mutations identified in patients with epilepsy were introduced into the full length human KCNT1 cDNA using quick-change site-directed mutagenesis protocol. Electrophysiological properties of different KCNT1 constructs were investigated using a heterologous expression system (HEK293T cells) and patch clamping. All mutations studied, except T314A, increased the amplitude of KCNT1 currents, and some mutations shifted the voltage dependence of KCNT1 open probability, increasing the proportion of channels open at the resting membrane potential. The T314A mutation did not affect KCNT1 current amplitude but abolished its voltage dependence. We observed a positive correlation between the severity of the neurological disorder and the KCNT1 channel open probability at resting membrane potential. This suggests that gain of function KCNT1 mutations cause epilepsy by increasing resting potassium conductance and suppressing the activity of inhibitory neurons. A reduction in action potential firing in inhibitory neurons due to excessively high resting potassium conductance leads to disinhibition of neural circuits, hyperexcitability and seizures.
Collapse
Affiliation(s)
- Grigori Y. Rychkov
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia
- Correspondence:
| | - Zeeshan Shaukat
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Chiao Xin Lim
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Rashid Hussain
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Ben J. Roberts
- Clinical and Health Sciences, Health and Biomedical Innovation, University of South Australia, Adelaide, SA 5000, Australia
| | - Claudia M. Bonardi
- Department of Woman’s and Child’s Health, Padua University Hospital, 35128 Padua, Italy
- The Danish Epilepsy Centre, 4293 Dianalund, Denmark
| | - Guido Rubboli
- Denmark Department of Clinical Medicine, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Brandon F. Meaney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Rikke S. Møller
- Department of Epilepsy Genetics and Personalized Treatment, Member of the ERN EpiCARE, The Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Michael G. Ricos
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Leanne M. Dibbens
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| |
Collapse
|
26
|
Ehtesham N, Mosallaei M, Beheshtian M, Khoshbakht S, Fadaee M, Vazehan R, Faraji Zonooz M, Karimzadeh P, Kahrizi K, Najmabadi H. Characterizing Genotypes and Phenotypes Associated with Dysfunction of Channel-Encoding Genes in a Cohort of Patients with Intellectual Disability. ARCHIVES OF IRANIAN MEDICINE 2022; 25:788-797. [PMID: 37543906 PMCID: PMC10685845 DOI: 10.34172/aim.2022.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 12/20/2021] [Indexed: 08/08/2023]
Abstract
BACKGROUND Ion channel dysfunction in the brain can lead to impairment of neuronal membranes and generate several neurological diseases, especially neurodevelopmental disorders. METHODS In this study, we set out to delineate the genotype and phenotype spectrums of 14 Iranian patients from 7 families with intellectual disability (ID) and/or developmental delay (DD) in whom genetic mutations were identified by next-generation sequencing (NGS) in 7 channel-encoding genes: KCNJ10, KCNQ3, KCNK6, CACNA1C, CACNA1G, SCN8A, and GRIN2B. Moreover, the data of 340 previously fully reported ID and/or DD cases with a mutation in any of these seven genes were combined with our patients to clarify the genotype and phenotype spectrum in this group. RESULTS In total, the most common phenotypes in 354 cases with ID/DD in whom mutation in any of these 7 channel-encoding genes was identified were as follows: ID (77.4%), seizure (69.8%), DD (59.8%), behavioral abnormality (29.9%), hypotonia (21.7%), speech disorder (21.5%), gait disturbance (20.9%), and ataxia (20.3%). Electroencephalography abnormality (33.9%) was the major brain imaging abnormality. CONCLUSION The results of this study broaden the molecular spectrum of channel pathogenic variants associated with different clinical presentations in individuals with ID and/or DD.
Collapse
Affiliation(s)
- Naeim Ehtesham
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Meysam Mosallaei
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Maryam Beheshtian
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Shahrouz Khoshbakht
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mahsa Fadaee
- Kariminejad – Najmabadi Pathology & Genetics Center, Tehran, Iran
| | - Raheleh Vazehan
- Kariminejad – Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Parvaneh Karimzadeh
- Department of Pediatric Neurology, School of Medicine, Pediatric Neurology Research Center, Mofid Children’s Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Kariminejad – Najmabadi Pathology & Genetics Center, Tehran, Iran
| |
Collapse
|
27
|
Blockade of Kv1.3 Potassium Channel Inhibits Microglia-Mediated Neuroinflammation in Epilepsy. Int J Mol Sci 2022; 23:ijms232314693. [PMID: 36499018 PMCID: PMC9740890 DOI: 10.3390/ijms232314693] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Epilepsy is a chronic neurological disorder whose pathophysiology relates to inflammation. The potassium channel Kv1.3 in microglia has been reported as a promising therapeutic target in neurological diseases in which neuroinflammation is involved, such as multiple sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease (PD), and middle cerebral artery occlusion/reperfusion (MCAO/R). Currently, little is known about the relationship between Kv1.3 and epilepsy. In this study, we found that Kv1.3 was upregulated in microglia in the KA-induced mouse epilepsy model. Importantly, blocking Kv1.3 with its specific small-molecule blocker 5-(4-phenoxybutoxy)psoralen (PAP-1) reduced seizure severity, prolonged seizure latency, and decreased neuronal loss. Mechanistically, we further confirmed that blockade of Kv1.3 suppressed proinflammatory microglial activation and reduced proinflammatory cytokine production by inhibiting the Ca2+/NF-κB signaling pathway. These results shed light on the critical function of microglial Kv1.3 in epilepsy and provided a potential therapeutic target.
Collapse
|
28
|
Leitner DF, Devore S, Laze J, Friedman D, Mills JD, Liu Y, Janitz M, Anink JJ, Baayen JC, Idema S, van Vliet EA, Diehl B, Scott C, Thijs R, Nei M, Askenazi M, Sivathamboo S, O’Brien T, Wisniewski T, Thom M, Aronica E, Boldrini M, Devinsky O. Serotonin receptor expression in hippocampus and temporal cortex of temporal lobe epilepsy patients by postictal generalized electroencephalographic suppression duration. Epilepsia 2022; 63:2925-2936. [PMID: 36053862 PMCID: PMC9669210 DOI: 10.1111/epi.17400] [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: 06/28/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Prolonged postictal generalized electroencephalographic suppression (PGES) is a potential biomarker for sudden unexpected death in epilepsy (SUDEP), which may be associated with dysfunctional autonomic responses and serotonin signaling. To better understand molecular mechanisms, PGES duration was correlated to 5HT1A and 5HT2A receptor protein expression and RNAseq from resected hippocampus and temporal cortex of temporal lobe epilepsy patients with seizures recorded in preoperative evaluation. METHODS Analyses included 36 cases (age = 14-64 years, age at epilepsy onset = 0-51 years, epilepsy duration = 2-53 years, PGES duration = 0-93 s), with 13 cases in all hippocampal analyses. 5HT1A and 5HT2A protein was evaluated by Western blot and histologically in hippocampus (n = 16) and temporal cortex (n = 9). We correlated PGES duration to our previous RNAseq dataset for serotonin receptor expression and signaling pathways, as well as weighted gene correlation network analysis (WGCNA) to identify correlated gene clusters. RESULTS In hippocampus, 5HT2A protein by Western blot positively correlated with PGES duration (p = .0024, R2 = .52), but 5HT1A did not (p = .87, R2 = .0020). In temporal cortex, 5HT1A and 5HT2A had lower expression and did not correlate with PGES duration. Histologically, PGES duration did not correlate with 5HT1A or 5HT2A expression in hippocampal CA4, dentate gyrus, or temporal cortex. RNAseq identified two serotonin receptors with expression that correlated with PGES duration in an exploratory analysis: HTR3B negatively correlated (p = .043, R2 = .26) and HTR4 positively correlated (p = .049, R2 = .25). WGCNA identified four modules correlated with PGES duration, including positive correlation with synaptic transcripts (p = .040, Pearson correlation r = .52), particularly potassium channels (KCNA4, KCNC4, KCNH1, KCNIP4, KCNJ3, KCNJ6, KCNK1). No modules were associated with serotonin receptor signaling. SIGNIFICANCE Higher hippocampal 5HT2A receptor protein and potassium channel transcripts may reflect underlying mechanisms contributing to or resulting from prolonged PGES. Future studies with larger cohorts should assess functional analyses and additional brain regions to elucidate mechanisms underlying PGES and SUDEP risk.
Collapse
Affiliation(s)
- Dominique F. Leitner
- Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, USA
- Center for Cognitive Neurology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| | - Sasha Devore
- Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| | - Juliana Laze
- Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| | - Daniel Friedman
- Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| | - James D. Mills
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
- Chalfont Centre for Epilepsy, Bucks, UK
| | - Yan Liu
- Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA
| | - Michael Janitz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jasper J. Anink
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Johannes C. Baayen
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Sander Idema
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam Neuroscience, De Boelelaan 1117, Amsterdam, the Netherlands
| | - Erwin A. van Vliet
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Catherine Scott
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Roland Thijs
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
| | - Maromi Nei
- Department of Neurology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - Manor Askenazi
- Biomedical Hosting LLC, Arlington, MA, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA
| | - Shobi Sivathamboo
- Department of Neuroscience, Alfred Health, Central Clinical School, Melbourne, Victoria, Australia
- Department Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Terence O’Brien
- Department of Neuroscience, Alfred Health, Central Clinical School, Melbourne, Victoria, Australia
- Department Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Thomas Wisniewski
- Center for Cognitive Neurology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Psychiatry, NYU Grossman School of Medicine, New York, NY, USA
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, London, UK
| | - Eleonora Aronica
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, the Netherlands
| | - Maura Boldrini
- Molecular Imaging and Neuropathology Division, New York State Psychiatric Institute, New York, NY, USA
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, USA
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, USA
- Department of Neurology, NYU Grossman School of Medicine, New York, NY, USA
| |
Collapse
|
29
|
Tian M, Li R, Yang F, Shu X, Li J, Chen J, Peng L, Yu X, Yang C. Phenotypic expansion of KCNH1-associated disorders to include isolated epilepsy and its associations with genotypes and molecular sub-regional locations. CNS Neurosci Ther 2022; 29:270-281. [PMID: 36285361 PMCID: PMC9804083 DOI: 10.1111/cns.14001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/20/2022] [Accepted: 09/29/2022] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Genotype-phenotypic correlation of KCNH1 variant remains elusive. This study aimed to expand the phenotypic spectrum of KCNH1 and explore the correlations between epilepsy and molecular sub-regional locations. METHODS We performed whole-exome sequencing in a cohort of 98 patients with familiar febrile seizure (FS) or epilepsy with unexplained etiologies. The damaging effects of variants were predicted by protein modeling and multiple in silico tools. All reported patients with KCNH1 pathogenic variants with detailed neurological phenotypes were analyzed to evaluate the genotype-phenotype correlation. RESULTS Two novel KCNH1 variants were identified in three cases, including two patients with FS with inherited variant (p.Ile113Thr) and one boy with epilepsy with de novo variant (p.Arg357Trp). Variant Ile113Thr was located within the eag domain, and variant p.Arg357Trp was located in transmembrane domain 4 of KCNH1, respectively. Two patients experienced refractory status epilepticus (SE), of which one patient died of acute encephalopathy induced by SE. Further analysis of 30 variants in 51 patients demonstrated that de novo variants were associated with epileptic encephalopathy, while mosaic/somatic or germline variants cause isolated epilepsy/FS. All hotspot variants associated with epileptic encephalopathy clustered in transmembrane domain (S4 and S6), while those with isolated epilepsy/seizures or TBS/ZLS without epilepsy were scattered in the KCNH1. CONCLUSIONS We found two novel missense variants of KCNH1 in three individuals with isolated FS/epilepsy. Variants in the KCNH1 cause a spectrum of epileptic disorders ranging from a benign form of genetic isolated epilepsy/FS to intractable form of epileptic encephalopathy. The genotypes and variant locations help explaining the phenotypic variation of patients with KCNH1 variant.
Collapse
Affiliation(s)
- Mao‐Qiang Tian
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Ren‐Ke Li
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | | | - Xiao‐Mei Shu
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Juan Li
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Jing Chen
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Long‐Ying Peng
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Xiao‐Hua Yu
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| | - Chang‐Jian Yang
- Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina,Department of PediatricsGuizhou Children's HospitalZunyiChina
| |
Collapse
|
30
|
Gao K, Lin Z, Wen S, Jiang Y. Potassium channels and epilepsy. Acta Neurol Scand 2022; 146:699-707. [PMID: 36225112 DOI: 10.1111/ane.13695] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/16/2022] [Indexed: 01/10/2023]
Abstract
With the development and application of next-generation sequencing technology, the aetiological diagnosis of genetic epilepsy is rapidly becoming easier and less expensive. Additionally, there is a growing body of research into precision therapy based on genetic diagnosis. The numerous genes in the potassium ion channel family constitute the largest family of ion channels: this family is divided into different subtypes. Potassium ion channels play a crucial role in the electrical activity of neurons and are directly involved in the mechanism of epileptic seizures. In China, scientific research on genetic diagnosis and studies of precision therapy for genetic epilepsy are progressing rapidly. Many cases of epilepsy caused by mutation of potassium channel genes have been identified, and several potassium channel gene targets and drug candidates have been discovered. The purpose of this review is to briefly summarize the progress of research on the precise diagnosis and treatment of potassium ion channel-related genetic epilepsy, especially the research conducted in China. Here in, we review several large cohort studies on the genetic diagnosis of epilepsy in China in recent years, summarized the proportion of potassium channel genes. We focus on the progress of precison therapy on some hot epilepsy related potassium channel genes: KCNA1, KCNA2, KCNB1, KCNC1, KCND2, KCNQ2, KCNQ3, KCNMA1, and KCNT1.
Collapse
Affiliation(s)
- Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China
| | - Zehong Lin
- Department of Neurology, Affiliated Children's Hospital of Capital Institute of Pediatrics, Beijing, China
| | - Sijia Wen
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing, China.,Children Epilepsy Center, Peking University First Hospital, Beijing, China.,Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing, China.,Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| |
Collapse
|
31
|
Sperandeo A, Tamburini C, Noakes Z, de la Fuente DC, Keefe F, Petter O, Plumbly W, Clifton N, Li M, Peall K. Cortical neuronal hyperexcitability and synaptic changes in SGCE mutation-positive myoclonus dystonia. Brain 2022; 146:1523-1541. [PMID: 36204995 PMCID: PMC10115238 DOI: 10.1093/brain/awac365] [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: 07/17/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Myoclonus Dystonia is a childhood-onset hyperkinetic movement disorder with a combined motor and psychiatric phenotype. It represents one of the few autosomal dominant inherited dystonic disorders and is caused by mutations in the ε-sarcoglycan (SGCE) gene. Work to date suggests that dystonia is caused by disruption of neuronal networks, principally basal ganglia-cerebello-thalamo-cortical circuits. Investigation of cortical involvement has primarily focused on disruption to interneuron inhibitory activity, rather than the excitatory activity of cortical pyramidal neurons. Here, we have sought to examine excitatory cortical glutamatergic activity using two approaches; the CRISPR/Cas9 editing of a human embryonic cell line, generating an SGCE compound heterozygous mutation, and three patient-derived induced pluripotent stem cell lines (iPSC) each gene edited to generate matched wild-type SGCE control lines. Differentiation towards a cortical neuronal phenotype demonstrated no significant differences in neither early- (PAX6, FOXG1) nor late-stage (CTIP2, TBR1) neurodevelopmental markers. However, functional characterisation using Ca2+ imaging and MEA approaches identified an increase in network activity, while single-cell patch clamp studies found a greater propensity towards action potential generation with larger amplitudes and shorter half-widths associated with SGCE-mutations. Bulk-RNA-seq analysis identified gene ontological enrichment for neuron projection development, synaptic signalling, and synaptic transmission. Examination of dendritic morphology found SGCE-mutations to be associated with a significantly higher number of branches and longer branch lengths, together with longer ion-channel dense axon initial segments, particularly towards the latter stages of differentiation (D80 and D100). Gene expression and protein quantification of key synaptic proteins (synaptophysin, synapsin and PSD95), AMPA and NMDA receptor subunits found no significant differences between the SGCE-mutation and matched wild-type lines. By contrast, significant changes to synaptic adhesion molecule expression were identified, namely higher pre-synaptic neurexin-1 and lower post-synaptic neuroligin-4 levels in the SGCE mutation carrying lines. Our study demonstrates an increased intrinsic excitability of cortical glutamatergic neuronal cells in the context of SGCE mutations, coupled with a more complex neurite morphology and disruption to synaptic adhesion molecules. These changes potentially represent key components to the development of the hyperkinetic clinical phenotype observed in Myoclonus Dystonia, as well a central feature to the wider spectrum of dystonic disorders, potentially providing targets for future therapeutic development.
Collapse
Affiliation(s)
- Alessandra Sperandeo
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Claudia Tamburini
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Zoe Noakes
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Daniel Cabezas de la Fuente
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Francesca Keefe
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Olena Petter
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - William Plumbly
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Nicholas Clifton
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Meng Li
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| | - Kathryn Peall
- Neuroscience and Mental Health Research Institute, Division of Psychological Medicine and Clinical Neuroscience, Cardiff University, Hadyn Ellis Building, Cardiff, CF24 4HQ
| |
Collapse
|
32
|
Galán-Vidal J, Socuéllamos PG, Baena-Nuevo M, Contreras L, González T, Pérez-Poyato MS, Valenzuela C, González-Lamuño D, Gandarillas A. A novel loss-of-function mutation of the voltage-gated potassium channel Kv10.2 involved in epilepsy and autism. Orphanet J Rare Dis 2022; 17:345. [PMID: 36068614 PMCID: PMC9446776 DOI: 10.1186/s13023-022-02499-z] [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] [Received: 01/27/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022] Open
Abstract
Background Novel developmental mutations associated with disease are a continuous challenge in medicine. Clinical consequences caused by these mutations include neuron and cognitive alterations that can lead to epilepsy or autism spectrum disorders. Often, it is difficult to identify the physiological defects and the appropriate treatments. Results We have isolated and cultured primary cells from the skin of a patient with combined epilepsy and autism syndrome. A mutation in the potassium channel protein Kv10.2 was identified. We have characterised the alteration of the mutant channel and found that it causes loss of function (LOF). Primary cells from the skin displayed a very striking growth defect and increased differentiation. In vitro treatment with various carbonic anhydrase inhibitors with various degrees of specificity for potassium channels, (Brinzolamide, Acetazolamide, Retigabine) restored the activation capacity of the mutated channel. Interestingly, the drugs also recovered in vitro the expansion capacity of the mutated skin cells. Furthermore, treatment with Acetazolamide clearly improved the patient regarding epilepsy and cognitive skills. When the treatment was temporarily halted the syndrome worsened again. Conclusions By in vitro studying primary cells from the patient and the activation capacity of the mutated protein, we could first, find a readout for the cellular defects and second, test pharmaceutical treatments that proved to be beneficial. The results show the involvement of a novel LOF mutation of a Potassium channel in autism syndrome with epilepsy and the great potential of in vitro cultures of primary cells in personalised medicine of rare diseases.
Collapse
Affiliation(s)
- Jesús Galán-Vidal
- Cell Cycle, Stem Cell Fate and Cancer Laboratory, Institute for Research Marqués de Valdecilla (IDIVAL), 39011, Santander, Spain
| | - Paula G Socuéllamos
- Instituto de Investigaciones Biomédicas Alberto Sols, IIBM, CSIC-UAM, Madrid, Spain.,Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
| | - María Baena-Nuevo
- Instituto de Investigaciones Biomédicas Alberto Sols, IIBM, CSIC-UAM, Madrid, Spain.,Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
| | - Lizbeth Contreras
- Cell Cycle, Stem Cell Fate and Cancer Laboratory, Institute for Research Marqués de Valdecilla (IDIVAL), 39011, Santander, Spain
| | - Teresa González
- Instituto de Investigaciones Biomédicas Alberto Sols, IIBM, CSIC-UAM, Madrid, Spain.,Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
| | - María S Pérez-Poyato
- Neuropediatric, University Hospital Marqués de Valdecilla, 39008, Santander, Spain
| | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Alberto Sols, IIBM, CSIC-UAM, Madrid, Spain. .,Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain.
| | - Domingo González-Lamuño
- Cell Cycle, Stem Cell Fate and Cancer Laboratory, Institute for Research Marqués de Valdecilla (IDIVAL), 39011, Santander, Spain. .,Paediatric Department, University of Cantabria University, Marqués de Valdecilla Hospital, 39008, Santander, Spain.
| | - Alberto Gandarillas
- Cell Cycle, Stem Cell Fate and Cancer Laboratory, Institute for Research Marqués de Valdecilla (IDIVAL), 39011, Santander, Spain. .,INSERM, Occitanie Méditerranée, 34394, Montpellier, France.
| |
Collapse
|
33
|
Tissue-wide cell-specific proteogenomic modeling reveals novel candidate risk genes in autism spectrum disorders. NPJ Syst Biol Appl 2022; 8:31. [PMID: 36068227 PMCID: PMC9448731 DOI: 10.1038/s41540-022-00243-8] [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] [Received: 02/28/2021] [Accepted: 08/05/2022] [Indexed: 11/08/2022] Open
Abstract
Autism spectrum disorders (ASD) are a set of complex neurodevelopmental diseases characterized with repetitive behavioral patterns and communication disabilities. Using a systems biology method called MAPSD (Markov Affinity-based Proteogenomic Signal Diffusion) for joint modeling of proteome dynamics and a wide array of omics datasets, we identified a list of candidate ASD risk genes. Leveraging the collected biological signals as well as a large-scale protein-protein interaction network adjusted based on single cell resolution proteome properties in four brain regions, we observed an agreement between the known and the newly identified candidate genes that are spatially enriched in neuronal cells within cerebral cortex at the protein level. Moreover, we created a detailed subcellular localization enrichment map of the known and the identified genes across 32 micro-domains and showed that neuronal cells and neuropils share the largest fraction of signal enrichment in cerebral cortex. Notably, we showed that the identified genes are among the transcriptional biomarkers of inhibitory and excitatory neurons in human frontal cortex. Intersecting the identified genes with a single cell RNA-seq data on ASD brains further evidenced that 20 candidate genes, including GRIK1, EMX2, STXBP6, and KCNJ3 are disrupted in distinct cell-types. Moreover, we showed that ASD risk genes are predominantly distributed in certain human interactome modules, and that the identified genes may act as the regulator for some of the known ASD loci. In summary, our study demonstrated how tissue-wide cell-specific proteogenomic modeling can reveal candidate genes for brain disorders that can be supported by convergent lines of evidence.
Collapse
|
34
|
Proskurina EY, Zaitsev AV. Regulation of Potassium and Chloride Concentrations in Nervous Tissue as a Method of Anticonvulsant Therapy. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022050015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Under some pathological conditions, such as pharmacoresistant
epilepsy, status epilepticus or certain forms of genetic abnormalities,
spiking activity of GABAergic interneurons may enhance excitation
processes in neuronal circuits and provoke the generation of ictal
discharges. As a result, anticonvulsants acting on the GABAergic
system may be ineffective or even increase seizure activity. This
paradoxical effect of the inhibitory system is due to ionic imbalances
in nervous tissue. This review addresses the mechanisms of ictal
discharge initiation in neuronal networks due to the imbalance of
chloride and potassium ions, as well as possible ways to regulate
ionic concentrations. Both the enhancement (or attenuation) of the
activity of certain neuronal ion transporters and ion pumps and
their additional expression via gene therapy can be effective in
suppressing seizure activity caused by ionic imbalances. The Na+–K+-pump,
NKCC1 and KCC2 cotransporters are important for maintaining proper
K+ and Cl– concentrations
in nervous tissue, having been repeatedly considered as pharmacological
targets for antiepileptic exposures. Further progress in this direction
is hampered by the lack of sufficiently selective pharmacological
tools and methods for providing effective drug delivery to the epileptic
focus. The use of the gene therapy techniques, such as overexpressing
of the KCC2 transporter in the epileptic focus, seems to be a more promising
approach. Another possible direction could be the use of optogenetic
tools, namely specially designed light-activated ion pumps or ion
channels. In this case, photon energy can be used to create the
required gradients of chloride and potassium ions, although these
methods also have significant limitations which complicate their
rapid introduction into medicine.
Collapse
|
35
|
Shimada S, Ng BG, White AL, Nickander KK, Turgeon C, Liedtke KL, Lam CT, Font-Montgomery E, Lourenço CM, He M, Peck DS, Umaña LA, Uhles CL, Haynes D, Wheeler PG, Bamshad MJ, Nickerson DA, Cushing T, Gates R, Gomez-Ospina N, Byers HM, Scalco FB, Martinez NN, Sachdev R, Smith L, Poduri A, Malone S, Harris R, Scheffer IE, Rosenzweig SD, Adams DR, Gahl WA, Malicdan MCV, Raymond KM, Freeze HH, Wolfe LA. Clinical, biochemical and genetic characteristics of MOGS-CDG: a rare congenital disorder of glycosylation. J Med Genet 2022; 59:jmedgenet-2021-108177. [PMID: 35790351 PMCID: PMC9813274 DOI: 10.1136/jmedgenet-2021-108177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/18/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To summarise the clinical, molecular and biochemical phenotype of mannosyl-oligosaccharide glucosidase-related congenital disorders of glycosylation (MOGS-CDG), which presents with variable clinical manifestations, and to analyse which clinical biochemical assay consistently supports diagnosis in individuals with bi-allelic variants in MOGS. METHODS Phenotypic characterisation was performed through an international and multicentre collaboration. Genetic testing was done by exome sequencing and targeted arrays. Biochemical assays on serum and urine were performed to delineate the biochemical signature of MOGS-CDG. RESULTS Clinical phenotyping revealed heterogeneity in MOGS-CDG, including neurological, immunological and skeletal phenotypes. Bi-allelic variants in MOGS were identified in 12 individuals from 11 families. The severity in each organ system was variable, without definite genotype correlation. Urine oligosaccharide analysis was consistently abnormal for all affected probands, whereas other biochemical analyses such as serum transferrin analysis was not consistently abnormal. CONCLUSION The clinical phenotype of MOGS-CDG includes multisystemic involvement with variable severity. Molecular analysis, combined with biochemical testing, is important for diagnosis. In MOGS-CDG, urine oligosaccharide analysis via matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry can be used as a reliable biochemical test for screening and confirmation of disease.
Collapse
Affiliation(s)
- Shino Shimada
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Bobby G. Ng
- Human Genetics Program, Sanford Burnham Prebys, La Jolla, CA, USA
| | - Amy L. White
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kim. K. Nickander
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Coleman Turgeon
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kristen L. Liedtke
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Christina T. Lam
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children’s Hospital and University of Washington, Seattle, WA, USA
| | | | - Charles M. Lourenço
- Faculdade de Medicina, Centro Universitario Estácio de Ribeirão Preto, Ribeirão Preto, SP, Brazil
- Neurogenetics Unit, Faculdade de Medicina de São José do Rio Preto (FAMERP), São José do Rio Preto, SP, Brazil
| | - Miao He
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Dawn S. Peck
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Luis A. Umaña
- Division of Genetics and Metabolism, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Crescenda L. Uhles
- Department of Genetics, Children’s Medical Center Dallas, Dallas, TX, USA
| | - Devon Haynes
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL, USA
| | - Patricia G. Wheeler
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL, USA
| | - Michael J. Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Tom Cushing
- Division of Pediatric Genetics, Department of Pediatrics, School of Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Ryan Gates
- Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | | | - Heather M. Byers
- Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | | | - Fernanda B. Scalco
- Laboratório de Erros Inatos do Metabolismo/LABEIM, Instituto de Química, Universidade Federal do Rio de Janeiro, Departamento de Bioquímica, Avenida Horácio Macedo, 1281, Bloco C, Polo de Química, Cidade Universitária, Rio de Janeiro, RJ, Brazil
| | - Noelia N. Martinez
- Center for Clinical Genetics, Sydney Children’s Hospital-Randwick, Sydney, New South Wales, Australia
| | - Rani Sachdev
- Center for Clinical Genetics, Sydney Children’s Hospital-Randwick, Sydney, New South Wales, Australia
- School of Women’s & Children’s Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Lacey Smith
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Annapurna Poduri
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Stephen Malone
- Department of Neurosciences, Queensland Children’s Hospital, Brisbane, Queensland, Australia
| | - Rebekah Harris
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
| | - Ingrid E. Scheffer
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
- Department of Pediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, VIC, Australia
- Murdoch Children’s Research Institute and Florey Institute, Melbourne, VIC, Australia
| | - Sergio D. Rosenzweig
- Department of Laboratory Medicine, Clinical Center, and Primary Immunodeficiency Clinic, National Institute of Allergy and Infectious Diseases, National Institute of Health, Bethesda, MD, USA
| | - David R. Adams
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - William A. Gahl
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - May CV. Malicdan
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Senior authors and contributed equally
| | - Kimiyo M. Raymond
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Senior authors and contributed equally
| | - Hudson H. Freeze
- Human Genetics Program, Sanford Burnham Prebys, La Jolla, CA, USA
- Senior authors and contributed equally
| | - Lynne A. Wolfe
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Senior authors and contributed equally
| |
Collapse
|
36
|
Soldovieri MV, Taglialatela M. The long and winding road to personalized medicine in KCNMA1-linked channelopathies revealed by novel variants associated with the Liang-Wang syndrome. Acta Physiol (Oxf) 2022; 235:e13854. [PMID: 35730691 DOI: 10.1111/apha.13854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/17/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Virginia Soldovieri
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Campobasso, Italy
| | | |
Collapse
|
37
|
Zhang L, Li S, Tai Z, Yu C, Xu Z. Gut Microbes Regulate Innate Immunity and Epilepsy. Front Neurosci 2022; 16:870197. [PMID: 35720723 PMCID: PMC9198293 DOI: 10.3389/fnins.2022.870197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 04/13/2022] [Indexed: 12/03/2022] Open
Abstract
Epilepsy is a common chronic brain disease. There are many clinical methods to control epileptic seizures, such as anti-seizure medications (ASMs) or surgical removal of epileptogenic lesions. However, the pathophysiology of epilepsy is still unknown, making it difficult to control or prevent it. The host’s immune system monitors gut microbes, interacts with microbes through pattern recognition receptors such as Toll-like receptors (TLRs) and NOD-like receptors (NLRs) expressed by innate immune cells, and activates immune responses in the body to kill pathogens and balance the relationship between microbes and host. In addition, inflammatory responses induced by the innate immune system are seen in animal models of epilepsy and temporal lobe epilepsy brain tissue to combat pathogens or injuries. This review summarizes the potential relationship between gut microbes, innate immunity, and epilepsy based on recent research to provide more hints for researchers to explore this field further.
Collapse
Affiliation(s)
- Linhai Zhang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Shuang Li
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Zhenzhen Tai
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Changyin Yu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Zucai Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| |
Collapse
|
38
|
Wang ZB, Qu J, Yang ZY, Liu DY, Jiang SL, Zhang Y, Yang ZQ, Mao XY, Liu ZQ. Integrated Analysis of Expression Profile and Potential Pathogenic Mechanism of Temporal Lobe Epilepsy With Hippocampal Sclerosis. Front Neurosci 2022; 16:892022. [PMID: 35784838 PMCID: PMC9243442 DOI: 10.3389/fnins.2022.892022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
Objective To investigate the potential pathogenic mechanism of temporal lobe epilepsy with hippocampal sclerosis (TLE+HS) by analyzing the expression profiles of microRNA/ mRNA/ lncRNA/ DNA methylation in brain tissues. Methods Brain tissues of six patients with TLE+HS and nine of normal temporal or parietal cortices (NTP) of patients undergoing internal decompression for traumatic brain injury (TBI) were collected. The total RNA was dephosphorylated, labeled, and hybridized to the Agilent Human miRNA Microarray, Release 19.0, 8 × 60K. The cDNA was labeled and hybridized to the Agilent LncRNA+mRNA Human Gene Expression Microarray V3.0,4 × 180K. For methylation detection, the DNA was labeled and hybridized to the Illumina 450K Infinium Methylation BeadChip. The raw data was extracted from hybridized images using Agilent Feature Extraction, and quantile normalization was performed using the Agilent GeneSpring. P-value < 0.05 and absolute fold change >2 were considered the threshold of differential expression data. Data analyses were performed using R and Bioconductor. BrainSpan database was used to screen for signatures that were not differentially expressed in normal human hippocampus and cortex (data from BrainSpan), but differentially expressed in TLE+HS’ hippocampus and NTP’ cortex (data from our cohort). The strategy “Guilt by association” was used to predict the prospective roles of each important hub mRNA, miRNA, or lncRNA. Results A significantly negative correlation (r < −0.5) was found between 116 pairs of microRNA/mRNA, differentially expressed in six patients with TLE+HS and nine of NTP. We examined this regulation network’s intersection with target gene prediction results and built a lncRNA-microRNA-Gene regulatory network with structural, and functional significance. Meanwhile, we found that the disorder of FGFR3, hsa-miR-486-5p, and lnc-KCNH5-1 plays a key vital role in developing TLE+HS.
Collapse
Affiliation(s)
- Zhi-Bin Wang
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacology, Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Central South University, Changsha, China
| | - Jian Qu
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhuan-Yi Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Ding-Yang Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Shi-Long Jiang
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacology, Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Central South University, Changsha, China
| | - Ying Zhang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Zhi-Quan Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Zhi-Quan Yang,
| | - Xiao-Yuan Mao
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacology, Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Central South University, Changsha, China
- Xiao-Yuan Mao,
| | - Zhao-Qian Liu
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, and National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacology, Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Central South University, Changsha, China
- *Correspondence: Zhao-Qian Liu,
| |
Collapse
|
39
|
Gain and loss of TASK3 channel function and its regulation by novel variation cause KCNK9 imprinting syndrome. Genome Med 2022; 14:62. [PMID: 35698242 PMCID: PMC9195326 DOI: 10.1186/s13073-022-01064-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genomics enables individualized diagnosis and treatment, but large challenges remain to functionally interpret rare variants. To date, only one causative variant has been described for KCNK9 imprinting syndrome (KIS). The genotypic and phenotypic spectrum of KIS has yet to be described and the precise mechanism of disease fully understood. METHODS This study discovers mechanisms underlying KCNK9 imprinting syndrome (KIS) by describing 15 novel KCNK9 alterations from 47 KIS-affected individuals. We use clinical genetics and computer-assisted facial phenotyping to describe the phenotypic spectrum of KIS. We then interrogate the functional effects of the variants in the encoded TASK3 channel using sequence-based analysis, 3D molecular mechanic and dynamic protein modeling, and in vitro electrophysiological and functional methodologies. RESULTS We describe the broader genetic and phenotypic variability for KIS in a cohort of individuals identifying an additional mutational hotspot at p.Arg131 and demonstrating the common features of this neurodevelopmental disorder to include motor and speech delay, intellectual disability, early feeding difficulties, muscular hypotonia, behavioral abnormalities, and dysmorphic features. The computational protein modeling and in vitro electrophysiological studies discover variability of the impact of KCNK9 variants on TASK3 channel function identifying variants causing gain and others causing loss of conductance. The most consistent functional impact of KCNK9 genetic variants, however, was altered channel regulation. CONCLUSIONS This study extends our understanding of KIS mechanisms demonstrating its complex etiology including gain and loss of channel function and consistent loss of channel regulation. These data are rapidly applicable to diagnostic strategies, as KIS is not identifiable from clinical features alone and thus should be molecularly diagnosed. Furthermore, our data suggests unique therapeutic strategies may be needed to address the specific functional consequences of KCNK9 variation on channel function and regulation.
Collapse
|
40
|
Bavan S, Goodkin HP, Papazian DM. Altered Closed State Inactivation Gating in Kv4.2 Channels Results in Developmental and Epileptic Encephalopathies in Human Patients. Hum Mutat 2022; 43:1286-1298. [PMID: 35510384 DOI: 10.1002/humu.24396] [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: 09/21/2021] [Revised: 04/27/2022] [Accepted: 05/01/2022] [Indexed: 11/06/2022]
Abstract
Kv4.2 subunits, encoded by KCND2, serve as the pore-forming components of voltage-gated, inactivating ISA K+ channels expressed in the brain. ISA channels inactivate without opening in response to subthreshold excitatory input, temporarily increasing neuronal excitability, the back propagation of action potentials, and Ca2+ influx into dendrites, thereby regulating mechanisms of spike timing-dependent synaptic plasticity. As previously described, a de novo variant in Kv4.2, p.Val404Met, is associated with an infant-onset developmental and epileptic encephalopathy (DEE) in monozygotic twin boys. The p.Val404Met variant enhances inactivation directly from closed states, but dramatically impairs inactivation after channel opening. We now report the identification of a closely related, novel, de novo variant in Kv4.2, p.Val402Leu, in a boy with an early-onset pharmacoresistant epilepsy that evolved to an epileptic aphasia syndrome (Continuous Spike Wave during Sleep Syndrome). Like p.Val404Met, the p.Val402Leu variant increases the rate of inactivation from closed states, but significantly slows inactivation after the pore opens. Although quantitatively the p.Val402Leu mutation alters channel kinetics less dramatically than p.Val404Met, our results strongly support the conclusion that p.Val402Leu and p.Val404Met cause the clinical features seen in the affected individuals and underscore the importance of closed state inactivation in ISA channels in normal brain development and function. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Selvan Bavan
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095-1571.,Labcorp Drug Development, Huntingdon, PE28 4HS, UK
| | - Howard P Goodkin
- Departments of Neurology and Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, 22903
| | - Diane M Papazian
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095-1571
| |
Collapse
|
41
|
Gain of function due to increased opening probability by two KCNQ5 pore variants causing developmental and epileptic encephalopathy. Proc Natl Acad Sci U S A 2022; 119:e2116887119. [PMID: 35377796 PMCID: PMC9169635 DOI: 10.1073/pnas.2116887119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Variants in genes encoding neuronally expressed potassium channel subunits are frequent causes of developmental and epileptic encephalopathies (DEEs). Characterization of their functional consequences is critical to confirm diagnosis, assess prognosis, and implement personalized treatments. In the present work, we describe two patients carrying variants in KCNQ5, a gene very recently and rarely found involved in DEEs, and reveal that they both cause remarkable gain-of-function consequences on channel activity. A PIP2-independent increase in open probability, without effects on membrane abundance or single-channel conductance, was responsible for the observed mutation-induced functional changes, thus revealing a pathomolecular disease mechanism for DEEs. Developmental and epileptic encephalopathies (DEEs) are neurodevelopmental diseases characterized by refractory epilepsy, distinct electroencephalographic and neuroradiological features, and various degrees of developmental delay. Mutations in KCNQ2, KCNQ3, and, more rarely, KCNQ5 genes encoding voltage-gated potassium channel subunits variably contributing to excitability control of specific neuronal populations at distinct developmental stages have been associated to DEEs. In the present work, the clinical features of two DEE patients carrying de novo KCNQ5 variants affecting the same residue in the pore region of the Kv7.5 subunit (G347S/A) are described. The in vitro functional properties of channels incorporating these variants were investigated with electrophysiological and biochemical techniques to highlight pathophysiological disease mechanisms. Currents carried by Kv7.5 G347 S/A channels displayed: 1) large (>10 times) increases in maximal current density, 2) the occurrence of a voltage-independent component, 3) slower deactivation kinetics, and 4) hyperpolarization shift in activation. All these functional features are consistent with a gain-of-function (GoF) pathogenetic mechanism. Similar functional changes were also observed when the same variants were introduced at the corresponding position in Kv7.2 subunits. Nonstationary noise analysis revealed that GoF effects observed for both Kv7.2 and Kv7.5 variants were mainly attributable to an increase in single-channel open probability, without changes in membrane abundance or single-channel conductance. The mutation-induced increase in channel opening probability was insensitive to manipulation of membrane levels of the critical Kv7 channel regulator PIP2. These results reveal a pathophysiological mechanism for KCNQ5-related DEEs, which might be exploited to implement personalized treatments.
Collapse
|
42
|
Gertler TS, Cherian S, DeKeyser JM, Kearney JA, George AL. K Na1.1 gain-of-function preferentially dampens excitability of murine parvalbumin-positive interneurons. Neurobiol Dis 2022; 168:105713. [PMID: 35346832 PMCID: PMC9169414 DOI: 10.1016/j.nbd.2022.105713] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/07/2022] [Accepted: 03/24/2022] [Indexed: 10/25/2022] Open
Abstract
KCNT1 encodes the sodium-activated potassium channel KNa1.1, expressed preferentially in the frontal cortex, hippocampus, cerebellum, and brainstem. Pathogenic missense variants in KCNT1 are associated with intractable epilepsy, namely epilepsy of infancy with migrating focal seizures (EIMFS), and sleep-related hypermotor epilepsy (SHE). In vitro studies of pathogenic KCNT1 variants support predominantly a gain-of-function molecular mechanism, yet how these variants behave in a neuron or ultimately drive formation of an epileptogenic circuit is an important and timely question. Using CRISPR/Cas9 gene editing, we introduced a gain-of-function variant into the endogenous mouse Kcnt1 gene. Compared to wild-type (WT) littermates, heterozygous and homozygous knock-in mice displayed greater seizure susceptibility to the chemoconvulsants kainate and pentylenetetrazole (PTZ), but not to flurothyl. Using acute slice electrophysiology in heterozygous and homozygous Kcnt1 knock-in and WT littermates, we demonstrated that CA1 hippocampal pyramidal neurons exhibit greater amplitude of miniature inhibitory postsynaptic currents in mutant mice with no difference in frequency, suggesting greater inhibitory tone associated with the Kcnt1 mutation. To address alterations in GABAergic signaling, we bred Kcnt1 knock-in mice to a parvalbumin-tdTomato reporter line, and found that parvalbumin-expressing (PV+) interneurons failed to fire repetitively with large amplitude current injections and were more prone to depolarization block. These alterations in firing can be recapitulated by direct application of the KNa1.1 channel activator loxapine in WT but are occluded in knock-in littermates, supporting a direct channel gain-of-function mechanism. Taken together, these results suggest that KNa1.1 gain-of-function dampens interneuron excitability to a greater extent than it impacts pyramidal neuron excitability, driving seizure susceptibility in a mouse model of KCNT1-associated epilepsy.
Collapse
Affiliation(s)
- Tracy S Gertler
- Division of Pediatric Neurology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, United States of America; Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America.
| | - Suraj Cherian
- Division of Pediatric Neurology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, United States of America; Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Jennifer A Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America.
| |
Collapse
|
43
|
Xiong J, Chen S, Chen B, Zhang W, Chen C, Deng X, He F, Zhang C, Yang L, Wang Y, Peng J, Yin F. A novel KCNQ2 missense variant in non-syndromic intellectual disability causes mild gain-of-function of Kv7.2 channel. Clin Chim Acta 2022; 530:74-80. [PMID: 35247435 DOI: 10.1016/j.cca.2022.03.001] [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: 02/02/2022] [Accepted: 03/01/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND Heterozygous variants of KCNQ2 can cause KCNQ2 associated neurodevelopmental disorder, mainly are benign (familial) neonatal or infantile epilepsy (B(F)NE or B(F)IE) and early-onset epileptic encephalopathy (EOEE). Moreover, some intermediate phenotypes, including intellectual disability (ID), and myokymia are related to the gene. METHODS We collected a non-syndromic ID male patient with a novel KCNQ2 missense variant. Whole cell electrophysiology, western blotting, and immunofluorescence were adopted to analyze the variant's functional alterations. RESULTS The patient presented with global developmental delay since his infancy. He still had profound ID but did not have epilepsy at the adolescence. The de novo KCNQ2 variant p.R75C (NM_172107) in the NH2 domain identified here showed a slightly hyperpolarized shift of activation curves and larger current density in homomeric configurations, which could be abolished in co-expression with Kv7.2 or Kv7.3 wild-type. Western blotting and immunocytochemistry supported that the expression of variant p.R75C is lower than the Kv7.2 wild-type. The findings indicated variant p.R75C cause mild gain-of-function (GOF) of Kv7.2 channel. CONCLUSIONS We report a non-syndromic ID patient with a KCNQ2 mild GOF variant, adding evidence for this rare clinical phenotype in the disorder. We propose that individuals with KCNQ2 GOF variants are prone to have cognitive impairments.
Collapse
Affiliation(s)
- Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Wen Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Chen Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Xiaolu Deng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ciliu Zhang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China; Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China.
| |
Collapse
|
44
|
Kingdom R, Wright CF. Incomplete Penetrance and Variable Expressivity: From Clinical Studies to Population Cohorts. Front Genet 2022; 13:920390. [PMID: 35983412 PMCID: PMC9380816 DOI: 10.3389/fgene.2022.920390] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 12/20/2022] Open
Abstract
The same genetic variant found in different individuals can cause a range of diverse phenotypes, from no discernible clinical phenotype to severe disease, even among related individuals. Such variants can be said to display incomplete penetrance, a binary phenomenon where the genotype either causes the expected clinical phenotype or it does not, or they can be said to display variable expressivity, in which the same genotype can cause a wide range of clinical symptoms across a spectrum. Both incomplete penetrance and variable expressivity are thought to be caused by a range of factors, including common variants, variants in regulatory regions, epigenetics, environmental factors, and lifestyle. Many thousands of genetic variants have been identified as the cause of monogenic disorders, mostly determined through small clinical studies, and thus, the penetrance and expressivity of these variants may be overestimated when compared to their effect on the general population. With the wealth of population cohort data currently available, the penetrance and expressivity of such genetic variants can be investigated across a much wider contingent, potentially helping to reclassify variants that were previously thought to be completely penetrant. Research into the penetrance and expressivity of such genetic variants is important for clinical classification, both for determining causative mechanisms of disease in the affected population and for providing accurate risk information through genetic counseling. A genotype-based definition of the causes of rare diseases incorporating information from population cohorts and clinical studies is critical for our understanding of incomplete penetrance and variable expressivity. This review examines our current knowledge of the penetrance and expressivity of genetic variants in rare disease and across populations, as well as looking into the potential causes of the variation seen, including genetic modifiers, mosaicism, and polygenic factors, among others. We also considered the challenges that come with investigating penetrance and expressivity.
Collapse
Affiliation(s)
- Rebecca Kingdom
- Institute of Biomedical and Clinical Science, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter, United Kingdom
| | - Caroline F Wright
- Institute of Biomedical and Clinical Science, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter, United Kingdom
| |
Collapse
|
45
|
Costa F, Guardiani C, Giacomello A. Exploring K v 1.2 Channel Inactivation Through MD Simulations and Network Analysis. Front Mol Biosci 2021; 8:784276. [PMID: 34988118 PMCID: PMC8721119 DOI: 10.3389/fmolb.2021.784276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022] Open
Abstract
The KCNA2 gene encodes the K v 1.2 channel, a mammalian Shaker-like voltage-gated K+ channel, whose defections are linked to neuronal deficiency and childhood epilepsy. Despite the important role in the kinetic behavior of the channel, the inactivation remained hereby elusive. Here, we studied the K v 1.2 inactivation via a combined simulation/network theoretical approach that revealed two distinct pathways coupling the Voltage Sensor Domain and the Pore Domain to the Selectivity Filter. Additionally, we mutated some residues implicated in these paths and we explained microscopically their function in the inactivation mechanism by computing a contact map. Interestingly, some pathological residues shown to impair the inactivation lay on the paths. In summary, the presented results suggest two pathways as the possible molecular basis of the inactivation mechanism in the K v 1.2 channel. These pathways are consistent with earlier mutational studies and known mutations involved in neuronal channelopathies.
Collapse
Affiliation(s)
| | | | - Alberto Giacomello
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, Rome, Italy
| |
Collapse
|
46
|
Casalia ML, Casabona JC, García C, Cavaliere Candedo V, Quintá HR, Farías MI, Gonzalez J, Gonzalez Morón D, Córdoba M, Consalvo D, Mostoslavsky G, Urbano FJ, Pasquini J, Murer MG, Rela L, Kauffman MA, Pitossi FJ. A familiar study on self-limited childhood epilepsy patients using hIPSC-derived neurons shows a bias towards immaturity at the morphological, electrophysiological and gene expression levels. Stem Cell Res Ther 2021; 12:590. [PMID: 34823607 PMCID: PMC8620942 DOI: 10.1186/s13287-021-02658-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 10/31/2021] [Indexed: 12/28/2022] Open
Abstract
Background Self-limited Childhood Epilepsies are the most prevalent epileptic syndrome in children. Its pathogenesis is unknown. In this disease, symptoms resolve spontaneously in approximately 50% of patients when maturity is reached, prompting to a maturation problem. The purpose of this study was to understand the molecular bases of this disease by generating and analyzing induced pluripotent stem cell-derived neurons from a family with 7 siblings, among whom 4 suffer from this disease.
Methods Two affected siblings and, as controls, a healthy sister and the unaffected mother of the family were studied. Using exome sequencing, a homozygous variant in the FYVE, RhoGEF and PH Domain Containing 6 gene was identified in the patients as a putative genetic factor that could contribute to the development of this familial disorder. After informed consent was signed, skin biopsies from the 4 individuals were collected, fibroblasts were derived and reprogrammed and neurons were generated and characterized by markers and electrophysiology. Morphological, electrophysiological and gene expression analyses were performed on these neurons. Results Bona fide induced pluripotent stem cells and derived neurons could be generated in all cases. Overall, there were no major shifts in neuronal marker expression among patient and control-derived neurons. Compared to two familial controls, neurons from patients showed shorter axonal length, a dramatic reduction in synapsin-1 levels and cytoskeleton disorganization. In addition, neurons from patients developed a lower action potential threshold with time of in vitro differentiation and the amount of current needed to elicit an action potential (rheobase) was smaller in cells recorded from NE derived from patients at 12 weeks of differentiation when compared with shorter times in culture. These results indicate an increased excitability in patient cells that emerges with the time in culture. Finally, functional genomic analysis showed a biased towards immaturity in patient-derived neurons. Conclusions We are reporting the first in vitro model of self-limited childhood epilepsy, providing the cellular bases for future in-depth studies to understand its pathogenesis. Our results show patient-specific neuronal features reflecting immaturity, in resonance with the course of the disease and previous imaging studies. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-021-02658-2.
Collapse
Affiliation(s)
| | | | - Corina García
- Institute Leloir Foundation- IIBBA-CONICET, Buenos Aires, Argentina
| | | | - Héctor Ramiro Quintá
- CONICET and Laboratorio de Medicina Experimental "Dr. J Toblli", Hospital Alemán, Buenos Aires, Argentina
| | | | - Joaquín Gonzalez
- Institute Leloir Foundation- IIBBA-CONICET, Buenos Aires, Argentina
| | - Dolores Gonzalez Morón
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Marta Córdoba
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Damian Consalvo
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Gustavo Mostoslavsky
- Center For Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, USA
| | - Francisco J Urbano
- Department of Physiology, Molecular and Cellular Biology "Dr. Héctor Maldonado", Faculty of Exact and Natural Sciences, University of Buenos Aires, IFIBYNE-CONICET, Buenos Aires, Argentina
| | - Juana Pasquini
- Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Mario Gustavo Murer
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Grupo de Neurociencia de Sistemas, Buenos Aires, Argentina.,Universidad de Buenos Aires - CONICET, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO), Buenos Aires, Argentina
| | - Lorena Rela
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Grupo de Neurociencia de Sistemas, Buenos Aires, Argentina.,Universidad de Buenos Aires - CONICET, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO), Buenos Aires, Argentina
| | - Marcelo A Kauffman
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina.
| | | |
Collapse
|
47
|
Miceli F, Guerrini R, Nappi M, Soldovieri MV, Cellini E, Gurnett CA, Parmeggiani L, Mei D, Taglialatela M. Distinct epilepsy phenotypes and response to drugs in KCNA1 gain- and loss-of function variants. Epilepsia 2021; 63:e7-e14. [PMID: 34778950 PMCID: PMC9299230 DOI: 10.1111/epi.17118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/01/2021] [Accepted: 10/22/2021] [Indexed: 11/29/2022]
Abstract
A wide phenotypic spectrum of neurological diseases is associated with KCNA1 (Kv1.1) variants. To investigate the molecular basis of such a heterogeneous clinical presentation and identify the possible correlation with in vitro phenotypes, we compared the functional consequences of three heterozygous de novo variants (p.P403S, p.P405L, and p.P405S) in Kv1.1 pore region found in four patients with severe developmental and epileptic encephalopathy (DEE), with those of a de novo variant in the voltage sensor (p.A261T) identified in two patients with mild, carbamazepine-responsive, focal epilepsy. Patch-clamp electrophysiology was used to investigate the functional properties of mutant Kv1.1 subunits, both expressed as homomers and heteromers with wild-type Kv1.1 subunits. KCNA1 pore mutations markedly decreased (p. P405S) or fully suppressed (p. P403S, p. P405L) Kv1.1-mediated currents, exerting loss-of-function (LoF) effects. By contrast, channels carrying the p.A261T variant exhibited a hyperpolarizing shift of the activation process, consistent with a gain-of-function (GoF) effect. The present results unveil a novel correlation between in vitro phenotype (GoF vs LoF) and clinical course (mild vs severe) in KCNA1-related phenotypes. The excellent clinical response to carbamazepine observed in the patients carrying the A261T variant suggests an exquisite sensitivity of KCNA1 GoF to sodium channel inhibition that should be further explored.
Collapse
Affiliation(s)
- Francesco Miceli
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Renzo Guerrini
- Neuroscience Department, A. Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Mario Nappi
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | | | - Elena Cellini
- Neuroscience Department, A. Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Christina A Gurnett
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Davide Mei
- Neuroscience Department, A. Meyer Children's Hospital, University of Florence, Florence, Italy
| | | |
Collapse
|
48
|
A Novel KCNA2 Variant in a Patient with Non-Progressive Congenital Ataxia and Epilepsy: Functional Characterization and Sensitivity to 4-Aminopyridine. Int J Mol Sci 2021; 22:ijms22189913. [PMID: 34576077 PMCID: PMC8469797 DOI: 10.3390/ijms22189913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/02/2021] [Accepted: 09/08/2021] [Indexed: 12/26/2022] Open
Abstract
Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2, E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2-disorders could benefit from variant-tailored therapeutic approaches, based on functional studies.
Collapse
|
49
|
Kaczmarek LK. The Na Vy paradox: reducing sodium currents increases excitability. Trends Neurosci 2021; 44:767-768. [PMID: 34373125 DOI: 10.1016/j.tins.2021.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 07/23/2021] [Indexed: 02/06/2023]
Abstract
Mutations that increase sodium currents in excitatory neurons typically produce hyperexcitability and epileptic seizures. Paradoxically, mutations that reduce NaV1.2 sodium currents also have a similar effect. Two research groups (Spratt et al. and Zhang et al.) have now found that in some excitatory neurons, loss of NaV1.2 increases intrinsic excitability by altering activation and/or expression of potassium channels.
Collapse
Affiliation(s)
- Leonard K Kaczmarek
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| |
Collapse
|
50
|
Spratt PWE, Alexander RPD, Ben-Shalom R, Sahagun A, Kyoung H, Keeshen CM, Sanders SJ, Bender KJ. Paradoxical hyperexcitability from Na V1.2 sodium channel loss in neocortical pyramidal cells. Cell Rep 2021; 36:109483. [PMID: 34348157 PMCID: PMC8719649 DOI: 10.1016/j.celrep.2021.109483] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 07/13/2021] [Indexed: 12/17/2022] Open
Abstract
Loss-of-function variants in the gene SCN2A, which encodes the sodium channel NaV1.2, are strongly associated with autism spectrum disorder and intellectual disability. An estimated 20%-30% of children with these variants also suffer from epilepsy, with altered neuronal activity originating in neocortex, a region where NaV1.2 channels are expressed predominantly in excitatory pyramidal cells. This is paradoxical, as sodium channel loss in excitatory cells would be expected to dampen neocortical activity rather than promote seizure. Here, we examined pyramidal neurons lacking NaV1.2 channels and found that they were intrinsically hyperexcitable, firing high-frequency bursts of action potentials (APs) despite decrements in AP size and speed. Compartmental modeling and dynamic-clamp recordings revealed that NaV1.2 loss prevented potassium channels from properly repolarizing neurons between APs, increasing overall excitability by allowing neurons to reach threshold for subsequent APs more rapidly. This cell-intrinsic mechanism may, therefore, account for why SCN2A loss-of-function can paradoxically promote seizure.
Collapse
Affiliation(s)
- Perry W E Spratt
- Neuroscience Graduate Program, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Ryan P D Alexander
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Roy Ben-Shalom
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Atehsa Sahagun
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Caroline M Keeshen
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Stephan J Sanders
- Department of Psychiatry, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Neuroscience Graduate Program, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
| |
Collapse
|