1
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Vierra NC. Compartmentalized signaling in the soma: Coordination of electrical and protein kinase A signaling at neuronal ER-plasma membrane junctions. Bioessays 2024; 46:e2400126. [PMID: 39268818 DOI: 10.1002/bies.202400126] [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: 05/28/2024] [Revised: 08/22/2024] [Accepted: 08/26/2024] [Indexed: 09/15/2024]
Abstract
Neuronal information processing depends on converting membrane depolarizations into compartmentalized biochemical signals that can modify neuronal activity and structure. However, our understanding of how neurons translate electrical signals into specific biochemical responses remains limited, especially in the soma where gene expression and ion channel function are crucial for neuronal activity. Here, I emphasize the importance of physically compartmentalizing action potential-triggered biochemical reactions within the soma. Emerging evidence suggests that somatic endoplasmic reticulum-plasma membrane (ER-PM) junctions are specialized organelles that coordinate electrical and biochemical signaling. The juxtaposition of ion channels and signaling proteins at a prominent subset of these sites enables compartmentalized calcium and cAMP-dependent protein kinase (PKA) signaling. I explore the hypothesis that these PKA-containing ER-PM junctions serve as critical sites for translating membrane depolarizations into PKA signals and identify key gaps in knowledge of the assembly, regulation, and neurobiological functions of this somatic signaling system.
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Affiliation(s)
- Nicholas C Vierra
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
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2
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Manville RW, Illeck CL, Santos C, Sidlow R, Abbott GW. A novel loss-of-function KCNB1 gene variant in a twin with global developmental delay and seizures. Front Cell Neurosci 2024; 18:1477989. [PMID: 39469306 PMCID: PMC11513283 DOI: 10.3389/fncel.2024.1477989] [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: 08/08/2024] [Accepted: 09/20/2024] [Indexed: 10/30/2024] Open
Abstract
Human voltage-gated potassium (Kv) channels are expressed by a 40-member gene family that is essential for normal electrical activity and is closely linked to various excitability disorders. Function-altering sequence variants in the KCNB1 gene, which encodes the neuronally expressed Kv2.1 channel, are associated with neurodevelopmental disorders including developmental delay with or without epileptic activity. In this study, we describe a 40-month-old fraternal twin who presented with severe neurodevelopmental delay. Electroencephalogram recordings at 19 months of age revealed poor sleep architecture and the presence of multifocal epileptiform discharges. The individual's fraternal twin was neurotypical, and there was no family history of neurodevelopmental delay or seizures. Whole genome sequencing at 33 months of age for the proband revealed a de novo variant in KCNB1 [c.1154C > T/p.Pro385Leu], encoding a proline-to-leucine substitution at residue 385, in the extracellular region immediately preceding Kv2.1 transmembrane segment 6 (S6). Cellular electrophysiological analysis of the effects of the gene variant in heterologously expressed Kv2.1 demonstrated that homozygous Kv2.1-P385L channels were completely non-functional. Channels generated by a 50/50 expression of wild-type Kv2.1 and Kv2.1-P385L, designed to mimic the proband's heterozygous status, revealed a partially dominant-negative effect, resulting in an 81% reduction in current magnitude. The dramatic loss of function in Kv2.1 is the most likely cause of the severe developmental delay and seizure activity in the proband, further enriching our phenotypic understanding of KCNB1 developmental encephalopathies.
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Affiliation(s)
- Rían W. Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Claire L. Illeck
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Cesar Santos
- Valley Children's Hospital, Madera, CA, United States
| | | | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA, United States
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3
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Zheng Y, Chen J. Voltage-gated potassium channels and genetic epilepsy. Front Neurol 2024; 15:1466075. [PMID: 39434833 PMCID: PMC11492950 DOI: 10.3389/fneur.2024.1466075] [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: 07/17/2024] [Accepted: 09/20/2024] [Indexed: 10/23/2024] Open
Abstract
Recent advances in exome and targeted sequencing have significantly improved the aetiological diagnosis of epilepsy, revealing an increasing number of epilepsy-related pathogenic genes. As a result, the diagnosis and treatment of epilepsy have become more accessible and more traceable. Voltage-gated potassium channels (Kv) regulate electrical excitability in neuron systems. Mutate Kv channels have been implicated in epilepsy as demonstrated in case reports and researches using gene-knockout mouse models. Both gain and loss-of-function of Kv channels lead to epilepsy with similar phenotypes through different mechanisms, bringing new challenges to the diagnosis and treatment of epilepsy. Research on genetic epilepsy is progressing rapidly, with several drug candidates targeting mutated genes or channels emerging. This article provides a brief overview of the symptoms and pathogenesis of epilepsy associated with voltage-gated potassium ion channels dysfunction and highlights recent progress in treatments. Here, we reviewed case reports of gene mutations related to epilepsy in recent years and summarized the proportion of Kv genes. Our focus is on the progress in precise treatments for specific voltage-gated potassium channel genes linked to epilepsy, including KCNA1, KCNA2, KCNB1, KCNC1, KCND2, KCNQ2, KCNQ3, KCNH1, and KCNH5.
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Affiliation(s)
| | - Jing Chen
- Department of Neurology, Children’s Hospital of Nanjing Medical University, Nanjing, China
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4
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Manville RW, Block SD, Illeck CL, Kottmeier J, Sidlow R, Abbott GW. A novel autism-associated KCNB1 mutation dramatically slows Kv2.1 potassium channel activation, deactivation and inactivation. Front Cell Neurosci 2024; 18:1438101. [PMID: 39135902 PMCID: PMC11317242 DOI: 10.3389/fncel.2024.1438101] [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: 05/25/2024] [Accepted: 07/15/2024] [Indexed: 08/15/2024] Open
Abstract
KCNB1, on human chromosome 20q13.3, encodes the alpha subunit of the Kv2.1 voltage gated potassium channel. Kv2.1 is ubiquitously expressed throughout the brain and is critical in controlling neuronal excitability, including in the hippocampus and pyramidal neurons. Human KCNB1 mutations are known to cause global development delay or plateauing, epilepsy, and behavioral disorders. Here, we report a sibling pair with developmental delay, absence seizures, autism spectrum disorder, hypotonia, and dysmorphic features. Whole exome sequencing revealed a heterozygous variant of uncertain significance (c. 342 C>A), p. (S114R) in KCNB1, encoding a serine to arginine substitution (S114R) in the N-terminal cytoplasmic region of Kv2.1. The siblings' father demonstrated autistic features and was determined to be an obligate KCNB1 c. 342 C>A carrier based on familial genetic testing results. Functional investigation of Kv2.1-S114R using cellular electrophysiology revealed slowing of channel activation, deactivation, and inactivation, resulting in increased net current after longer membrane depolarizations. To our knowledge, this is the first study of its kind that compares the presentation of siblings each with a KCNB1 disorder. Our study demonstrates that Kv2.1-S114R has profound cellular and phenotypic consequences. Understanding the mechanisms underlying KCNB1-linked disorders aids clinicians in diagnosis and treatment and provides potential therapeutic avenues to pursue.
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Affiliation(s)
- Rían W. Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | - Samantha D. Block
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Be’er Sheva, Israel
- Medical School for International Health, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Claire L. Illeck
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | - Jessica Kottmeier
- Department of Pediatric Genetics, Children’s Hospital, University of Missouri, Columbia, MO, United States
| | - Richard Sidlow
- Department of Pediatric Genetics, Children’s Hospital, University of Missouri, Columbia, MO, United States
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
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5
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Kang SK, Hawkins NA, Thompson CH, Baker EM, Echevarria-Cooper DM, Barse L, Thenstedt T, Dixon CJ, Speakes N, George AL, Kearney JA. Altered neurological and neurobehavioral phenotypes in a mouse model of the recurrent KCNB1-p.R306C voltage-sensor variant. Neurobiol Dis 2024; 194:106470. [PMID: 38485094 PMCID: PMC11024897 DOI: 10.1016/j.nbd.2024.106470] [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: 03/29/2023] [Revised: 02/23/2024] [Accepted: 03/06/2024] [Indexed: 03/21/2024] Open
Abstract
Pathogenic variants in KCNB1 are associated with a neurodevelopmental disorder spectrum that includes global developmental delays, cognitive impairment, abnormal electroencephalogram (EEG) patterns, and epilepsy with variable age of onset and severity. Additionally, there are prominent behavioral disturbances, including hyperactivity, aggression, and features of autism spectrum disorder. The most frequently identified recurrent variant is KCNB1-p.R306C, a missense variant located within the S4 voltage-sensing transmembrane domain. Individuals with the R306C variant exhibit mild to severe developmental delays, behavioral disorders, and a diverse spectrum of seizures. Previous in vitro characterization of R306C described altered sensitivity and cooperativity of the voltage sensor and impaired capacity for repetitive firing of neurons. Existing Kcnb1 mouse models include dominant negative missense variants, as well as knockout and frameshifts alleles. While all models recapitulate key features of KCNB1 encephalopathy, mice with dominant negative alleles were more severely affected. In contrast to existing loss-of-function and dominant-negative variants, KCNB1-p.R306C does not affect channel expression, but rather affects voltage-sensing. Thus, modeling R306C in mice provides a novel opportunity to explore impacts of a voltage-sensing mutation in Kcnb1. Using CRISPR/Cas9 genome editing, we generated the Kcnb1R306C mouse model and characterized the molecular and phenotypic effects. Consistent with the in vitro studies, neurons from Kcnb1R306C mice showed altered excitability. Heterozygous and homozygous R306C mice exhibited hyperactivity, altered susceptibility to chemoconvulsant-induced seizures, and frequent, long runs of slow spike wave discharges on EEG, reminiscent of the slow spike and wave activity characteristic of Lennox Gastaut syndrome. This novel model of channel dysfunction in Kcnb1 provides an additional, valuable tool to study KCNB1 encephalopathies. Furthermore, this allelic series of Kcnb1 mouse models will provide a unique platform to evaluate targeted therapies.
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Affiliation(s)
- Seok Kyu Kang
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Nicole A Hawkins
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Christopher H Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Erin M Baker
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Dennis M Echevarria-Cooper
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Levi Barse
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Tyler Thenstedt
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Conor J Dixon
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nathan Speakes
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Jennifer A Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA.
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6
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Chen LL, Naesström M, Halvorsen M, Fytagoridis A, Crowley SB, Mataix-Cols D, Rück C, Crowley JJ, Pascal D. Genomics of severe and treatment-resistant obsessive-compulsive disorder treated with deep brain stimulation: A preliminary investigation. Am J Med Genet B Neuropsychiatr Genet 2024:e32983. [PMID: 38650085 PMCID: PMC11493841 DOI: 10.1002/ajmg.b.32983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 01/25/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Individuals with severe and treatment-resistant obsessive-compulsive disorder (trOCD) represent a small but severely disabled group of patients. Since trOCD cases eligible for deep brain stimulation (DBS) probably comprise the most severe end of the OCD spectrum, we hypothesize that they may be more likely to have a strong genetic contribution to their disorder. Therefore, while the worldwide population of DBS-treated cases may be small (~300), screening these individuals with modern genomic methods may accelerate gene discovery in OCD. As such, we have begun to collect DNA from trOCD cases who qualify for DBS, and here we report results from whole exome sequencing and microarray genotyping of our first five cases. All participants had previously received DBS in the bed nucleus of stria terminalis (BNST), with two patients responding to the surgery and one showing a partial response. Our analyses focused on gene-disruptive rare variants (GDRVs; rare, predicted-deleterious single-nucleotide variants or copy number variants overlapping protein-coding genes). Three of the five cases carried a GDRV, including a missense variant in the ion transporter domain of KCNB1, a deletion at 15q11.2, and a duplication at 15q26.1. The KCNB1 variant (hg19 chr20-47991077-C-T, NM_004975.3:c.1020G>A, p.Met340Ile) causes substitution of methionine for isoleucine in the trans-membrane region of neuronal potassium voltage-gated ion channel KV2.1. This KCNB1 substitution (Met340Ile) is located in a highly constrained region of the protein where other rare missense variants have previously been associated with neurodevelopmental disorders. The patient carrying the Met340Ile variant responded to DBS, which suggests that genetic factors could potentially be predictors of treatment response in DBS for OCD. In sum, we have established a protocol for recruiting and genomically characterizing trOCD cases. Preliminary results suggest that this will be an informative strategy for finding risk genes in OCD.
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Affiliation(s)
- Long Long Chen
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - Matilda Naesström
- Department of Clinical Sciences/Psychiatry, Umeå University, Umeå, Sweden
| | - Matthew Halvorsen
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anders Fytagoridis
- Department of Neurosurgery, Karolinska Institutet and University Hospital, Stockholm, Sweden
| | | | - David Mataix-Cols
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - Christian Rück
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - James J. Crowley
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Diana Pascal
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
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7
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Le Roux M, Benallegue N, Gueden S, Rupin-Mas M, Van Bogaert P. Care of pharmaco-resistant absence seizures in childhood. Rev Neurol (Paris) 2024; 180:251-255. [PMID: 38388226 DOI: 10.1016/j.neurol.2024.01.002] [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: 11/16/2023] [Revised: 01/03/2024] [Accepted: 01/08/2024] [Indexed: 02/24/2024]
Abstract
In childhood absence epilepsy, pharmaco-resistance occurs in 20-30% of patients. In that situation, glucose transporter type 1 deficiency has to be ruled out, especially if absences started before the age of four years and if neurological signs are present. If ethosuximide, valproate and lamotrigine have failed in monotherapy or in association, there are currently no valuable therapeutic options. The same rules apply for epilepsy with myoclonic absences. Importantly, arguments supporting that making the patient seizure-free will improve eventual associated cognitive deficits such as attention deficit are very weak. Therefore, limiting the cognitive side effects of the anti-epileptic drugs has always to be a priority when faced with typical refractory absences in childhood. In epilepsy with eyelid myoclonia, the majority of patients are pharmaco-resistant. However, absence seizures, if present, tend to be very brief, and seizures are limited in many patients to eyelid myoclonia that eventually do not affect their quality of life and are well attenuated by wearing blue lenses. Atypical absences occurring in the course a developmental and/or epileptic encephalopathy are often pharmaco-resistant. In that situation, characterizing the type of epilepsy syndrome and searching for a specific genetic or structural etiology are needed to offer the best therapeutic options to the patient.
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Affiliation(s)
- M Le Roux
- Department of Pediatric Neurology, CHU d'Angers, Angers, France
| | - N Benallegue
- Department of Pediatric Neurology, CHU d'Angers, Angers, France
| | - S Gueden
- Department of Pediatric Neurology, CHU d'Angers, Angers, France
| | - M Rupin-Mas
- Department of Pediatric Neurology, CHU d'Angers, Angers, France
| | - P Van Bogaert
- Department of Pediatric Neurology, CHU d'Angers, Angers, France; Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, Angers, France.
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8
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Ferrera G, Ricci E, Peron A, Parrini E, Vignoli A, Canevini MP. Continuous spike-wave of slow sleep in a patient with KCNB1-related epilepsy responsive to highly purified cannabidiol: a case report and comparison with literature. Neurocase 2024; 30:68-72. [PMID: 38769754 DOI: 10.1080/13554794.2024.2354952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 05/03/2024] [Indexed: 05/22/2024]
Abstract
KCNB1-associated encephalopathy is characterized by intellectual disability (ID), autism spectrum disorder and epilepsy. Specific treatments are still lacking. We describe a 12-year-old boy with severe ID and treatment-resistant seizures due to a pathogenic KCNB1 variant. His EEG showed a CSWS pattern. Aged 11, he started treatment with highly purified cannabidiol (CBD) and has been seizure free for 18 months, with significant EEG and social skills improvements. This suggests CBD may benefit CSWS, likely due to its anti-inflammatory properties. Some preclinical studies also indicate CBDs interact with voltage-gated channels, leading us to speculate its possible role for treating KCNB1 related encephalopathy.
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Affiliation(s)
- Giulia Ferrera
- Epilepsy Center-Sleep Medicine, University of Milan and ASST Santi Paolo e Carlo, Milan, Italy
| | - Emilia Ricci
- Epilepsy Center-Sleep Medicine, University of Milan and ASST Santi Paolo e Carlo, Milan, Italy
| | - Angela Peron
- Division of Medical Genetics, Department of Pediatrics, University of Utah Health, Salt Lake City, USA
- Medical Genetics, ASST Santi Paolo e Carlo, Ospedale San Paolo, Milan, Italy
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Aglai Vignoli
- Child and Adolescent Neuropsychiatr, University of Milan and ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Maria Paola Canevini
- Epilepsy Center-Sleep Medicine, University of Milan and ASST Santi Paolo e Carlo, Milan, Italy
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9
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Simeone KA, Martenz DM, Iyer SH, Booth CP, Herr SE, Matthews SA, Draves SB, Heinemann LL, Greenberg PL, Lhatoo SD, Donner E, Simeone TA. Personalization of SUDEP risk: A survey of transient subclinical comorbid changes. Epilepsy Res 2024; 199:107259. [PMID: 38086218 DOI: 10.1016/j.eplepsyres.2023.107259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 10/29/2023] [Accepted: 11/13/2023] [Indexed: 01/13/2024]
Abstract
OBJECTIVE Preclinical data report within subject modifiable ailments emerge weeks prior to SUDEP, including sleep disorders and cardiorespiratory changes; findings which support anecdotal clinical data. Here, we bridge preclinical findings with future clinical/preclinical studies, and survey whether caretakers or family members of victims noticed transient changes prior to SUDEP. The aim of this pilot study is to identify potential modifiable changes that may synergistically increase SUDEP risk for future research. METHODS A mobile electronic survey was posted on SUDEP community websites. The survey queried whether changes in seizures, sleep, physical well-being, emotional well-being, cognition, breathing, or heart rate were noticed before SUDEP. RESULTS The most profound finding was that 85% of victims had multiple transient ailments prior to SUDEP. Changes in seizures (28/54), and sleep (30/58) occurred in more than 50% of the victims and represent the most influential changes identified. The second and third most influential changes were a reduction in physical well-being (25/57) and emotional well-being (26/56). Changes were observed within the last two months of life in approximately one third of the cases, and more than four months prior to SUDEP in approximately one third of cases, indicating a potential time frame for proactive preventative strategies. Respondents also noted changes in cognition (16/55), breathing (9/54) or heart rate (8/55). Data indicate these changes may be associated with increased SUDEP risk within subject. Study limitations include the responses were based on memory, there was a potential for data to be over reported, and caretakers were not prompted to observe changes a priori, thus some existing changes may have gone unnoticed. SIGNIFICANCE Data support the preclinical findings that transient, subclinical (i.e., not severe enough to require medical intervention), modifiable ailments may increase risk of SUDEP. This suggests that just as an epilepsy type can change over a lifetime and epilepsy type-specific treatments can reduce SUDEP risk, further personalization of SUDEP risk will improve our understanding as to whether variables contribute to risk differently across lifespan. Thus, with a dynamic capacity to change, differing factors may contribute to the distribution of risk probability within an individual at any given time. Understanding whether different combinations of transient changes are specific to epilepsy type, age, or sex needs to be determined to move the field forward in hopes of developing a personalized approach to preventative strategies.
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Affiliation(s)
- Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States.
| | | | - Shruthi H Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Cameron P Booth
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Shelby E Herr
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Samantha B Draves
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Laura L Heinemann
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Pierce L Greenberg
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
| | - Samden D Lhatoo
- Department of Neurology, University of Texas Health Science Center at Houston John P and Katherine G McGovern Medical School, United States
| | - Elizabeth Donner
- Department of Paediatrics, Division of Neurology, Hospital for Sick Children, Canada
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, United States
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10
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Alam KA, Svalastoga P, Martinez A, Glennon JC, Haavik J. Potassium channels in behavioral brain disorders. Molecular mechanisms and therapeutic potential: A narrative review. Neurosci Biobehav Rev 2023; 152:105301. [PMID: 37414376 DOI: 10.1016/j.neubiorev.2023.105301] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
Potassium channels (K+-channels) selectively control the passive flow of potassium ions across biological membranes and thereby also regulate membrane excitability. Genetic variants affecting many of the human K+-channels are well known causes of Mendelian disorders within cardiology, neurology, and endocrinology. K+-channels are also primary targets of many natural toxins from poisonous organisms and drugs used within cardiology and metabolism. As genetic tools are improving and larger clinical samples are being investigated, the spectrum of clinical phenotypes implicated in K+-channels dysfunction is rapidly expanding, notably within immunology, neurosciences, and metabolism. K+-channels that previously were considered to be expressed in only a few organs and to have discrete physiological functions, have recently been found in multiple tissues and with new, unexpected functions. The pleiotropic functions and patterns of expression of K+-channels may provide additional therapeutic opportunities, along with new emerging challenges from off-target effects. Here we review the functions and therapeutic potential of K+-channels, with an emphasis on the nervous system, roles in neuropsychiatric disorders and their involvement in other organ systems and diseases.
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Affiliation(s)
| | - Pernille Svalastoga
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway; Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | | | - Jeffrey Colm Glennon
- Conway Institute for Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland.
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Norway.
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11
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Frankel E, Podder A, Sharifi M, Pillai R, Belnap N, Ramsey K, Dodson J, Venugopal P, Brzezinski M, Llaci L, Gerald B, Mills G, Sanchez-Castillo M, Balak CD, Szelinger S, Jepsen WM, Siniard AL, Richholt R, Naymik M, Schrauwen I, Craig DW, Piras IS, Huentelman MJ, Schork NJ, Narayanan V, Rangasamy S. Genetic and Protein Network Underlying the Convergence of Rett-Syndrome-like (RTT-L) Phenotype in Neurodevelopmental Disorders. Cells 2023; 12:1437. [PMID: 37408271 DOI: 10.3390/cells12101437] [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: 02/07/2023] [Revised: 04/20/2023] [Accepted: 04/29/2023] [Indexed: 07/07/2023] Open
Abstract
Mutations of the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2) cause classical forms of Rett syndrome (RTT) in girls. A subset of patients who are recognized to have an overlapping neurological phenotype with RTT but are lacking a mutation in a gene that causes classical or atypical RTT can be described as having a 'Rett-syndrome-like phenotype (RTT-L). Here, we report eight patients from our cohort diagnosed as having RTT-L who carry mutations in genes unrelated to RTT. We annotated the list of genes associated with RTT-L from our patient cohort, considered them in the light of peer-reviewed articles on the genetics of RTT-L, and constructed an integrated protein-protein interaction network (PPIN) consisting of 2871 interactions connecting 2192 neighboring proteins among RTT- and RTT-L-associated genes. Functional enrichment analysis of RTT and RTT-L genes identified a number of intuitive biological processes. We also identified transcription factors (TFs) whose binding sites are common across the set of RTT and RTT-L genes and appear as important regulatory motifs for them. Investigation of the most significant over-represented pathway analysis suggests that HDAC1 and CHD4 likely play a central role in the interactome between RTT and RTT-L genes.
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Affiliation(s)
- Eric Frankel
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Avijit Podder
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Megan Sharifi
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Roshan Pillai
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Newell Belnap
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Julius Dodson
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Pooja Venugopal
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Molly Brzezinski
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Lorida Llaci
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Brittany Gerald
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Gabrielle Mills
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Meredith Sanchez-Castillo
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Chris D Balak
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Szabolcs Szelinger
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Wayne M Jepsen
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ashley L Siniard
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ryan Richholt
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Marcus Naymik
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
| | - David W Craig
- Department of Translational Genomics, University of Southern California, Los Angeles, CA 90033, USA
| | - Ignazio S Piras
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Matthew J Huentelman
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Nicholas J Schork
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Vinodh Narayanan
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Sampathkumar Rangasamy
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
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12
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Chen LL, Naesström M, Halvorsen M, Fytagoridis A, Mataix-Cols D, Rück C, Crowley JJ, Pascal D. Genomics of severe and treatment-resistant obsessive-compulsive disorder treated with deep brain stimulation: a preliminary investigation. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.04.15.23288623. [PMID: 37131580 PMCID: PMC10153313 DOI: 10.1101/2023.04.15.23288623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Individuals with severe and treatment-resistant obsessive-compulsive disorder (trOCD) represent a small but severely disabled group of patients. Since trOCD cases eligible for deep brain stimulation (DBS) probably comprise the most severe end of the OCD spectrum, we hypothesize that they may be more likely to have a strong genetic contribution to their disorder. Therefore, while the worldwide population of DBS-treated cases may be small (~300), screening these individuals with modern genomic methods may accelerate gene discovery in OCD. As such, we have begun to collect DNA from trOCD cases who qualify for DBS, and here we report results from whole exome sequencing and microarray genotyping of our first five cases. All participants had previously received DBS in the bed nucleus of stria terminalis (BNST), with two patients responding to the surgery and one showing a partial response. Our analyses focused on gene-disruptive rare variants (GDRVs; rare, predicted-deleterious single-nucleotide variants or copy number variants overlapping protein-coding genes). Three of the five cases carried a GDRV, including a missense variant in the ion transporter domain of KCNB1, a deletion at 15q11.2, and a duplication at 15q26.1. The KCNB1 variant (hg19 chr20-47991077-C-T, NM_004975.3:c.1020G>A, p.Met340Ile) causes substitution of methionine for isoleucine in the trans-membrane region of neuronal potassium voltage-gated ion channel KV2.1. This KCNB1 substitution (Met340Ile) is located in a highly constrained region of the protein where other rare missense variants have previously been associated with neurodevelopmental disorders. The patient carrying the Met340Ile variant responded to DBS, which suggests that genetic factors could potentially be predictors of treatment response in DBS for OCD. In sum, we have established a protocol for recruiting and genomically characterizing trOCD cases. Preliminary results suggest that this will be an informative strategy for finding risk genes in OCD.
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Affiliation(s)
- Long Long Chen
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - Matilda Naesström
- Department of Clinical Sciences/Psychiatry, Umeå University, Umeå, Sweden
| | - Matthew Halvorsen
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anders Fytagoridis
- Department of Neurosurgery, Karolinska Institutet and University Hospital, Stockholm, Sweden
| | - David Mataix-Cols
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - Christian Rück
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
| | - James J. Crowley
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Diana Pascal
- Department of Clinical Neuroscience, Centre for Psychiatry Research Karolinska Institutet, & Stockholm Health Care Services, Stockholm, Sweden
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13
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Xia C, Liu C, Ren S, Cai Y, Zhang Q, Xia C. Potassium channels, tumorigenesis and targeted drugs. Biomed Pharmacother 2023; 162:114673. [PMID: 37031494 DOI: 10.1016/j.biopha.2023.114673] [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] [Received: 02/28/2023] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/11/2023] Open
Abstract
Potassium channels play an important role in human physiological function. Recently, various molecular mechanisms have implicated abnormal functioning of potassium channels in the proliferation, migration, invasion, apoptosis, and cancer stem cell phenotype formation. Potassium channels also mediate the association of tumor cells with the tumor microenvironment. Meanwhile, potassium channels are important targets for cancer chemotherapy. A variety of drugs exert anti-cancer effects by modulating potassium channels in tumor cells. Therefore, there is a need to understand how potassium channels participate in tumor development and progression, which could reveal new, novel targets for cancer diagnosis and treatment. This review summarizes the roles of voltage-gated potassium channels, calcium-activated potassium channels, inwardly rectifying potassium channels, and two-pore domain potassium channels in tumorigenesis and the underlying mechanism of potassium channel-targeted drugs. Therefore, the study lays the foundation for rational and effective drug design and individualized clinical therapeutics.
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Affiliation(s)
- Cong Xia
- Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province 116023, China
| | - Can Liu
- Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong Province 528099, China; School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China
| | - Shuangyi Ren
- Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province 116023, China
| | - Yantao Cai
- Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong Province 528099, China
| | - Qianshi Zhang
- Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning Province 116023, China.
| | - Chenglai Xia
- Affiliated Foshan Maternity and Child Healthcare Hospital, Southern Medical University, Foshan, Guangdong Province 528099, China; School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong Province 510515, China.
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14
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Kang SK, Hawkins NA, Echevarria-Cooper DM, Baker EM, Dixon CJ, Speakes N, Kearney JA. Altered neurological and neurobehavioral phenotypes in a mouse model of the recurrent KCNB1-p.R306C voltage-sensor variant. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.29.534736. [PMID: 37034689 PMCID: PMC10081335 DOI: 10.1101/2023.03.29.534736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Pathogenic variants in KCNB1 are associated with a neurodevelopmental disorder spectrum that includes global developmental delays, cognitive impairment, abnormal electroencephalogram (EEG) patterns, and epilepsy with variable age of onset and severity. Additionally, there are prominent behavioral disturbances, including hyperactivity, aggression, and features of autism spectrum disorder. The most frequently identified recurrent variant is KCNB1-p.R306C, a missense variant located within the S4 voltage-sensing transmembrane domain. Individuals with the R306C variant exhibit mild to severe developmental delays, behavioral disorders, and a diverse spectrum of seizures. Previous in vitro characterization of R306C described loss of voltage sensitivity and cooperativity of the sensor and inhibition of repetitive firing. Existing Kcnb1 mouse models include dominant negative missense variants, as well as knockout and frameshifts alleles. While all models recapitulate key features of KCNB1 encephalopathy, mice with dominant negative alleles were more severely affected. In contrast to existing loss-of-function and dominant-negative variants, KCNB1-p.R306C does not affect channel expression, but rather affects voltage-sensing. Thus, modeling R306C in mice provides a novel opportunity to explore impacts of a voltage-sensing mutation in Kcnb1. Using CRISPR/Cas9 genome editing, we generated the Kcnb1R306C mouse model and characterized the molecular and phenotypic effects. Heterozygous and homozygous R306C mice exhibited pronounced hyperactivity, altered susceptibility to flurothyl and kainic acid induced-seizures, and frequent, long runs of spike wave discharges on EEG. This novel model of channel dysfunction in Kcnb1 provides an additional, valuable tool to study KCNB1 encephalopathies. Furthermore, this allelic series of Kcnb1 mouse models will provide a unique platform to evaluate targeted therapies.
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Affiliation(s)
- Seok Kyu Kang
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Nicole A Hawkins
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Dennis M Echevarria-Cooper
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Erin M Baker
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Conor J Dixon
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nathan Speakes
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jennifer A Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
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15
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Hiraide T, Akita T, Uematsu K, Miyamoto S, Nakashima M, Sasaki M, Fukuda A, Kato M, Saitsu H. A novel de novo KCNB1 variant altering channel characteristics in a patient with periventricular heterotopia, abnormal corpus callosum, and mild seizure outcome. J Hum Genet 2023; 68:25-31. [PMID: 36257979 DOI: 10.1038/s10038-022-01090-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/31/2022] [Accepted: 10/01/2022] [Indexed: 01/20/2023]
Abstract
KCNB1 encodes the α-subunit of Kv2.1, the main contributor to neuronal delayed rectifier potassium currents. The subunit consists of six transmembrane α helices (S1-S6), comprising the voltage-sensing domain (S1-S4) and the pore domain (S5-P-S6). Heterozygous KCNB1 pathogenic variants are associated with developmental and epileptic encephalopathy. Here we report an individual who shows the milder phenotype compared to the previously reported cases, including delayed language development, mild intellectual disability, attention deficit hyperactivity disorder, late-onset epilepsy responsive to an antiepileptic drug, elevation of serum creatine kinase, and peripheral axonal neuropathy. On the other hand, his brain MRI showed characteristic findings including periventricular heterotopia, polymicrogyria, and abnormal corpus callosum. Exome sequencing identified a novel de novo KCNB1 variant c.574G>A, p.(Ala192Thr) located in the S1 segment of the voltage-sensing domain. Functional analysis using the whole-cell patch-clamp technique in Neuro2a cells showed that the Ala192Thr mutant reduces both activation and inactivation of the channel at membrane voltages in the range of -50 to -30 mV. Our case could expand the phenotypic spectrum of patients with KCNB1 variants, and suggested that variants located in the S1 segment might be associated with a milder outcome of seizures.
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Affiliation(s)
- Takuya Hiraide
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.,Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan. .,Division of Health Science, Department of Basic Nursing, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| | - Kenji Uematsu
- Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Sachiko Miyamoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masayuki Sasaki
- Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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16
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Uctepe E, Esen FN, Tümer S, Mancılar H, Yeşilyurt A. KCNB1 frameshift variant caused inherited intellectual disability, developmental delay, and seizure. Intractable Rare Dis Res 2022; 11:219-221. [PMID: 36457583 PMCID: PMC9709620 DOI: 10.5582/irdr.2022.01096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/07/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
Potassium voltage-gated channel subfamily B member 1 (KCNB1) encodes Kv2.1 potassium channel. KCNB1 mutations are known to cause global developmental delay, behavioral disorders, and various epilepsies. Most variants occur de novo and are rarely inherited. Here, we report a 14-year-old male patient who was admitted to our clinic with seizures, developmental delay history, and intellectual disability. Brain magnetic resonance image (MRI) was normal and electroencephalogram (EEG) showed spike and sharp-wave complexes emerging in the left hemisphere parietooccipital areas, which were paroxysmally generalized. We performed whole exome sequence analysis (WES) and identified a heterozygous frameshift mutation c.522delA in exon 1 of KCNB1 (NM_004975.4) predicting a premature stop codon p.Lys174Asnfs*20 in the proband. Sanger sequencing confirmed the heterozygous c.522delA mutation in the proband and his mother who also had epilepsy and learning difficulties. His 45 year old mother had used antiepileptic drugs for 9 years after a seizure episode at 12 years old. Also, his mother's uncle's son is nonverbal and has developmental delay and epilepsy. Our study shows that frameshift mutation cytoplasmic domain of KCNB1 gene can cause intrafamilial phenotypic variability and relatively mild clinical findings in these patients.
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Affiliation(s)
- Eyyup Uctepe
- Acıbadem Ankara Tissue Typing Laboratory, Ankara, Turkey
| | | | - Sait Tümer
- Acibadem Labgen Genetic Diagnosis Center, İstanbul, Turkey
| | | | - Ahmet Yeşilyurt
- Acibadem Labgen Genetic Diagnosis Center, İstanbul, Turkey
- Acibadem Maslak Hospital, İstanbul,Turkey
- Address correspondence to:Ahmet Yeşilyurt, Acibadem Labgen Genetic Diagnosis Center, Kerem Aydınlar Kampüsü Kayışdağı Cad. B Blok No:32, 34752 Ataşehir/İstanbul, Turkey. E-mail:
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17
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Sepela RJ, Stewart RG, Valencia LA, Thapa P, Wang Z, Cohen BE, Sack JT. The AMIGO1 adhesion protein activates Kv2.1 voltage sensors. Biophys J 2022; 121:1395-1416. [PMID: 35314141 PMCID: PMC9072587 DOI: 10.1016/j.bpj.2022.03.020] [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: 07/10/2021] [Revised: 11/11/2021] [Accepted: 03/16/2022] [Indexed: 11/30/2022] Open
Abstract
Kv2 voltage-gated potassium channels are modulated by amphoterin-induced gene and open reading frame (AMIGO) neuronal adhesion proteins. Here, we identify steps in the conductance activation pathway of Kv2.1 channels that are modulated by AMIGO1 using voltage-clamp recordings and spectroscopy of heterologously expressed Kv2.1 and AMIGO1 in mammalian cell lines. AMIGO1 speeds early voltage-sensor movements and shifts the gating charge-voltage relationship to more negative voltages. The gating charge-voltage relationship indicates that AMIGO1 exerts a larger energetic effect on voltage-sensor movement than is apparent from the midpoint of the conductance-voltage relationship. When voltage sensors are detained at rest by voltage-sensor toxins, AMIGO1 has a greater impact on the conductance-voltage relationship. Fluorescence measurements from voltage-sensor toxins bound to Kv2.1 indicate that with AMIGO1, the voltage sensors enter their earliest resting conformation, yet this conformation is less stable upon voltage stimulation. We conclude that AMIGO1 modulates the Kv2.1 conductance activation pathway by destabilizing the earliest resting state of the voltage sensors.
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Affiliation(s)
- Rebecka J Sepela
- Department of Physiology and Membrane Biology, University of California, Davis, California
| | - Robert G Stewart
- Department of Physiology and Membrane Biology, University of California, Davis, California
| | - Luis A Valencia
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Parashar Thapa
- Department of Physiology and Membrane Biology, University of California, Davis, California
| | - Zeming Wang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Bruce E Cohen
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California; Division of Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California, Davis, California; Department of Anesthesiology and Pain Medicine, University of California, Davis, California.
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18
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Xiong J, Liu Z, Chen S, Kessi M, Chen B, Duan H, Deng X, Yang L, Peng J, Yin F. Correlation Analyses of Clinical Manifestations and Variant Effects in KCNB1-Related Neurodevelopmental Disorder. Front Pediatr 2022; 9:755344. [PMID: 35071126 PMCID: PMC8767024 DOI: 10.3389/fped.2021.755344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/14/2021] [Indexed: 12/24/2022] Open
Abstract
Objective: Vitro functional analyses of KCNB1 variants have been done to disclose possible pathogenic mechanisms in KCNB1-related neurodevelopmental disorder. "Complete or partial loss of function (LoF)," "dominant-negative (DN) effect" are applied to describe KCNB1 variant's molecular phenotypes. The study here aimed to investigate clinical presentations and variant effects associations in the disorder. Methods: We reported 10 Chinese pediatric patients with KCNB1-related neurodevelopmental disorder here. Functional experiments on newly reported variants, including electrophysiology and protein expression, were performed in vitro. Phenotypic, functional, and genetic data in the cohort and published literature were collected. According to their variants' molecular phenotypes, patients were grouped into complete or partial LoF, and DN effect or non-dominant-negative (non-DN) effect to compare their clinical features. Results: Nine causative KCNB1 variants in 10 patients were identified in the cohort, including eight novel and one reported. Epilepsy (9/10), global developmental delay (10/10), and behavior issues (7/10) were common clinical features in our patients. Functional analyses of 8 novel variants indicated three partial and five complete LoF variants, five DN and three non-DN effect variants. Patient 1 in our series with truncated variants, whose functional results supported haploinsufficiency, had the best prognosis. Cases in complete LoF group had earlier seizure onset age (64.3 vs. 16.7%, p = 0.01) and worse seizure outcomes (18.8 vs. 66.7%, p = 0.03), and patients in DN effect subgroup had multiple seizure types compared to those in non-DN effect subgroup (65.5 vs. 30.8%, p = 0.039). Conclusion: Patients with KCNB1 variants in the Asian cohort have similar clinical manifestations to those of other races. Truncated KCNB1 variants exhibiting with haploinsufficiency molecular phenotype are linked to milder phenotypes. Individuals with complete LoF and DN effect KCNB1 variants have more severe seizure attacks than the other two subgroups.
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Affiliation(s)
- Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Shimeng Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Miriam Kessi
- 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
| | - Haolin Duan
- 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
| | - Lifen Yang
- 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
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19
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Bar C, Breuillard D, Kuchenbuch M, Jennesson M, Le Guyader G, Isnard H, Rolland A, Doummar D, Fluss J, Afenjar A, Berquin P, De Saint Martin A, Dupont S, Goldenberg A, Lederer D, Lesca G, Maurey H, Meyer P, Mignot C, Nica A, Odent S, Poisson A, Scalais E, Sekhara T, Vrielynck P, Barcia G, Nabbout R. Adaptive behavior and psychiatric comorbidities in KCNB1 encephalopathy. Epilepsy Behav 2022; 126:108471. [PMID: 34915430 DOI: 10.1016/j.yebeh.2021.108471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 12/13/2022]
Abstract
AIM KCNB1 encephalopathy encompasses a broad phenotypic spectrum associating intellectual disability, behavioral disturbances, and epilepsies of various severity. Using standardized parental questionnaires, we aimed to capture the heterogeneity of the adaptive and behavioral features in a series of patients with KCNB1 pathogenic variants. METHODS We included 25 patients with a KCNB1 encephalopathy, aged from 3.2 to 34.1 years (median = 10 years). Adaptive functioning was assessed in all patients using the French version of the Vineland Adaptive Behavior Scales, Second Edition (VABS-II) questionnaire. We screened global behavior with the Childhood Behavioral Check-List (CBCL, Achenbach) and autism spectrum disorder (ASD) with the Social Communication Questionnaire (SCQ). We used a cluster analysis to identify subgroups of adaptive profiles. RESULTS VABS-II questionnaire showed pathological adaptive behavior in all participants with a severity of adaptive deficiency ranging from mild in 8/20 to severe in 7/20. Eight out of 16 were at risk of Attention Problems at the CBCL and 13/18 were at risk of autism spectrum disorder (ASD). The adaptive behavior composite score significantly decreased with age (Spearman's Rho=-0.72, p<0.001) but not the equivalent ages, suggesting stagnation and slowing but no regression over time. The clustering analysis identified two subgroups of patients, one showing more severe adaptive behavior. The severity of the epilepsy phenotype predicted the severity of the behavioral profile with a sensitivity of 70% and a specificity of 90.9%. CONCLUSION This study confirms the deleterious consequences of early-onset epilepsy in addition to the impact of the gene dysfunction in patients with KCNB1 encephalopathy. ASD and attention disorders are frequent. Parental questionnaires should be considered as useful tools for early screening and care adaptation.
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Affiliation(s)
- Claire Bar
- APHP, Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, member of ERN EPICARE, Université de Paris, Paris, France; Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Université de Paris, Paris, France
| | - Delphine Breuillard
- APHP, Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, member of ERN EPICARE, Université de Paris, Paris, France; Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Université de Paris, Paris, France
| | - Mathieu Kuchenbuch
- APHP, Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, member of ERN EPICARE, Université de Paris, Paris, France; Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Université de Paris, Paris, France
| | | | - Gwenaël Le Guyader
- Department of Genetics, CHU de Poitiers, BP 577, 86021 Poitiers Cedex, France; EA3808 - NEUVACOD Unité neurovasculaire et troubles cognitifs, Université de Poitiers, Pôle Biologie Santé, France
| | - Hervé Isnard
- Pediatric Neurologist, Medical Office 28 rue de la république, Lyon 69002, France
| | - Anne Rolland
- Department of Pediatrics, CHU de NANTES, Nantes, France
| | - Diane Doummar
- Department of Pediatric Neurology, AP-HP, Hôpital Armand Trousseau, Sorbonne Université, Paris, France
| | - Joel Fluss
- Pediatric Neurology Unit, Geneva Children's Hospital, 6 rue Willy-Donzé, 1211 Genève 4, Switzerland
| | - Alexandra Afenjar
- Sorbonne Universités, Centre de Référence Malformations et maladies congénitales du cervelet et déficiences intellectuelles de causes rares, département de génétique et embryologie médicale, Hôpital Trousseau, AP-HP, Paris, France
| | - Patrick Berquin
- Department of Pediatric Neurology, CHU Amiens-Picardie, Université de Picardie Jules Verne, Amiens France Pediatric Neurology Unit, France
| | - Anne De Saint Martin
- Department of Pediatric Neurology, Strasbourg University Hospital, Strasbourg, Hôpital de Hautepierre, Strasbourg, France
| | - Sophie Dupont
- Epileptology Unit and Rehabilitation Unit AP-HP, GH Pitie-Salpêtrière-Charles Foix, F-75013 Paris, France; Sorbonne University, UPMC Univ. Paris 06, F-75005 Paris, France
| | - Alice Goldenberg
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, CHU Rouen, Rouen, France
| | | | - Gaétan Lesca
- Department of Genetics, Hospices Civils de Lyon, 69002 Lyon, France; Institut NeuroMyoGène, CNRS UMR 5310 - INSERM U1217, Université de Lyon, Université Claude Bernard Lyon 1, France
| | - Hélène Maurey
- Department of Pediatric Neurology, AP-HP, Hôpital Universitaire Bicêtre, Kremlin Bicêtre, France
| | - Pierre Meyer
- Department of Pediatric Neurology, CHU Montpellier, Montpellier, France; PhyMedExp, U1046 INSERM, UMR9214 CNRS, Université de Montpellier, Montpellier, France
| | - Cyril Mignot
- INSERM, U 1127, CNRS UMR 7225, Sorbonne Université, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; APHP, Sorbonne Université, Groupe Hospitalier Pitié-Salpêtrière, Department of Genetics, Centre de Reference Déficience Intellectuelle de Causes Rares
| | - Anca Nica
- Neurology Department, Center for Clinical Research (CIC 1414), Rennes University Hospital, France; Laboratory Of Signal Processing (LTSI), UMR 1099 INSERM, Rennes F-35000, France
| | - Sylvie Odent
- Service de Génétique clinique, Reference Ccentre for Rare Developmental Abnormalities CLAD-Ouest, member of ERN ITHACA, CHU Rennes, France; CNRS UMR 6290 Institut de Génétique et Développement de Rennes IGDR, Univ Rennes, Rennes, France
| | - Alice Poisson
- GénoPsy, Reference Center for Diagnosis and Management of Genetic Psychiatric Disorders, Centre Hospitalier le Vinatier and EDR-Psy Team (Centre National de la Recherche Scientifique & Lyon 1 Claude Bernard University), France
| | - Emmanuel Scalais
- Pediatric Neurology Unit, Centre Hospitalier de Luxembourg, Luxembourg
| | - Tayeb Sekhara
- Department of Pediatric Neurology, C.H.I.R.E.C, Brussels, Belgium
| | - Pascal Vrielynck
- William Lennox Neurological Hospital, Reference Center for Refractory Epilepsy UCLouvain, Ottignies, Belgium
| | - Giulia Barcia
- Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Université de Paris, Paris, France; APHP, Department of Clinical Genetics, Necker-Enfants Malades Hospital, Paris, France
| | - Rima Nabbout
- APHP, Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, member of ERN EPICARE, Université de Paris, Paris, France; Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Imagine Institute, Université de Paris, Paris, France.
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20
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Liu Z, Yang X, Guo P, Wang F, Xia W, Chen Y, Zou M, Sun C. The association between gene polymorphisms in voltage-gated potassium channels Kv2.1 and Kv4.2 and susceptibility to autism spectrum disorder. Front Psychiatry 2022; 13:994166. [PMID: 36756634 PMCID: PMC9900626 DOI: 10.3389/fpsyt.2022.994166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a heritable form of neurodevelopmental disorder that arises through synaptic dysfunction. Given the involvement of voltage-gated potassium (Kv) channels in the regulation of synaptic plasticity, we aimed to explore the relationship between the genetic variants in the KCNB1 and KCND2 genes (encoding Kv2.1 and Kv4.2, respectively) and the risk of developing ASD. METHODS A total of 243 patients with ASD and 243 healthy controls were included in the present study. Sixty single nucleotide polymorphisms (SNPs) (35 in KCNB1 and 25 in KCND2) were genotyped using the Sequenom Mass Array. RESULTS There were no significant differences in the distribution of allele frequencies and genotype frequencies in KCNB1 between cases and controls. However, the differences were significant in the allelic distribution of KCND2 rs1990429 (p Bonferroni < 0.005) and rs7793864 (p Bonferroni < 0.005) between the two groups. KCND2 rs7800545 (p FDR = 0.045) in the dominant model and rs1990429 (p FDR < 0.001) and rs7793864 (p FDR < 0.001) in the over-dominant model were associated with ASD risk. The G/A genotype of rs1990429 in the over-dominant model and the G/A-G/G genotype of rs7800545 in the dominant model were correlated with lower severity in the Autism Diagnostic Interview-Revised (ADI-R) restricted repetitive behavior (RRB) domain. CONCLUSION Our results provide evidence that KCND2 gene polymorphism is strongly associated with ASD susceptibility and the severity of RRB.
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Affiliation(s)
- Zehui Liu
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
| | - Xiaolei Yang
- Department of Preventive Medicine, School of Public Health, Qiqihar Medical University, Qiqihar, China
| | - Peiwen Guo
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
| | - Feng Wang
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
| | - Wei Xia
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
| | - Yuxin Chen
- Faculty of Arts and Science, University of Toronto, Toronto, ON, Canada
| | - Mingyang Zou
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
| | - Caihong Sun
- Department of Children's and Adolescent Health, Public Health College, Harbin Medical University, Harbin, China
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21
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Mild phenotype in a patient with developmental and epileptic encephalopathy carrying a novel de novo KCNB1 variant. Neurol Sci 2021; 42:4325-4327. [PMID: 34176003 DOI: 10.1007/s10072-021-05388-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
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22
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Nikitin ES, Vinogradova LV. Potassium channels as prominent targets and tools for the treatment of epilepsy. Expert Opin Ther Targets 2021; 25:223-235. [PMID: 33754930 DOI: 10.1080/14728222.2021.1908263] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION K+ channels are of great interest to epilepsy research as mutations in their genes are found in humans with inherited epilepsy. At the level of cellular physiology, K+ channels control neuronal intrinsic excitability and are the main contributors to membrane repolarization of active neurons. Recently, a genetically modified voltage-dependent K+ channel has been patented as a remedy for epileptic seizures. AREAS COVERED We review the role of potassium channels in excitability, clinical and experimental evidence for the association of potassium channelopathies with epilepsy, the targeting of K+ channels by drugs, and perspectives of gene therapy in epilepsy with the expression of extra K+ channels in the brain. EXPERT OPINION Control over K+ conductance is of great potential benefit for the treatment of epilepsy. Nowadays, gene therapy affecting K+ channels is one of the most promising approaches to treat pharmacoresistant focal epilepsy.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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