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Krüger J, Lerche H. Retigabine and gabapentin restore channel function and neuronal firing in a cellular model of an epilepsy-associated dominant-negative KCNQ5 variant. Neuropharmacology 2024; 250:109892. [PMID: 38428481 DOI: 10.1016/j.neuropharm.2024.109892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/19/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
KCNQ5 encodes the voltage-gated potassium channel KV7.5, a member of the KV7 channel family, which conducts the M-current. This current is a potent regulator of neuronal excitability by regulating membrane potential in the subthreshold range of action potentials and mediating the medium and slow afterhyperpolarization. Recently, we have identified five loss-of-function variants in KCNQ5 in patients with genetic generalized epilepsy. Using the most severe dominant-negative variant (R359C), we set out to investigate pharmacological therapeutic intervention by KV7 channel openers on channel function and neuronal firing. Retigabine and gabapentin increased R359C-derived M-current amplitudes in HEK cells expressing homomeric or heteromeric mutant KV7.5 channels. Retigabine was most effective in restoring K+ currents. Ten μM retigabine was sufficient to reach the level of WT currents without retigabine, whereas 100 μM of gabapentin showed less than half of this effect and application of 50 μM ZnCl2 only significantly increased M-current amplitude in heteromeric channels. Overexpression of KV7.5-WT potently inhibited neuronal firing by increasing the M-current, whereas R359C overexpression had the opposite effect and additionally decreased the medium afterhyperpolarization current. Both aforementioned drugs and Zn2+ reversed the effect of R359C expression by reducing firing to nearly normal levels at high current injections. Our study shows that a dominant-negative variant with a complete loss-of-function in KV7.5 leads to largely increased neuronal firing which may explain a neuronal hyperexcitability in patients. KV7 channel openers, such as retigabine or gabapentin, could be treatment options for patients currently displaying pharmacoresistant epilepsy and carrying loss-of-function variants in KCNQ5.
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Affiliation(s)
- Johanna Krüger
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Straße 27, 72076, Tübingen, Germany.
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Straße 27, 72076, Tübingen, Germany.
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Zhang YJ, Wang TS, Zhu XM, Yu LF, Zhang LM, Zhou YF, Wang Y, Zhou SZ. Biallelic variants of KCNQ2 in early infantile developmental and epileptic encephalopathy. Seizure 2024; 116:159-161. [PMID: 36934001 DOI: 10.1016/j.seizure.2023.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/02/2023] [Accepted: 03/11/2023] [Indexed: 03/14/2023] Open
Affiliation(s)
- Yun-Jian Zhang
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Tian-Shuang Wang
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Xiao-Mei Zhu
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Li-Fei Yu
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Lin-Mei Zhang
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Yuan-Feng Zhou
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Yi Wang
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Shui-Zhen Zhou
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China.
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Zhang Y, Xue Y, Ma Y, Du X, Lu B, Wang Y, Yan Z. Improved classification and pathogenicity assessment by comprehensive functional studies in a large data set of KCNQ2 variants. Life Sci 2024; 339:122378. [PMID: 38142737 DOI: 10.1016/j.lfs.2023.122378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
AIMS The paucity of functional annotations on hundreds of KCNQ2 variants impedes the diagnosis and treatment of KCNQ2-related disorders. The aims of this work were to determine the functional properties of 331 clinical KCNQ2 variants, interpreted the pathogenicity of 331 variants using functional data,and explored the association between homomeric channel functions and phenotypes. MAIN METHODS We collected 145 KCNQ2 variants from 232 epilepsy patients and 186 KCNQ2 missense variants from the ClinVar database. Whole-cell patch-clamp recording was used to classify the function of 331 variants. Subsequently, we proposed 24 criteria for the pathogenicity interpretation of KCNQ2 variants and used them to assess pathogenicity of 331 variants. Finally, we analyzed the clinical phenotypes of patients carrying these variants, and explored the correlations between functional mechanisms and phenotypes. KEY FINDINGS In the homozygous state, 287 were classified as loss-of-function and 14 as gain-of-function. In the more clinically relative heterozygous state, 200 variants exhibited functional impairment, 121 of which showed dominant-negative effects on wild-type KCNQ2 subunits. After introducing functional data as strong-level evidence to interpret pathogenicity, over half of variants (169/331) were reclassified and 254 were classified as pathogenic/likely pathogenic. Moreover, dominant-negative effect and haploinsufficiency were identified as primary mechanisms in DEE/ID and SeLNE, respectively. The degree of impairment of channel function correlated with the phenotype severity. SIGNIFICANCE Our study reveals the possible cause of KCNQ2-related disorders at the molecular level, provides compelling evidence for clinical classification of KCNQ2 variants, and expands the knowledge of correlations between functional mechanisms and phenotypes.
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Affiliation(s)
- Yuwei Zhang
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China; Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China.
| | - Yuqing Xue
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China; Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China.
| | - Yu Ma
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Xiaonan Du
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Boxun Lu
- Neurology Department at Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Life Sciences, Fudan University, Shanghai, China.
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 201102, China.
| | - Zhiqiang Yan
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China; State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China; Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China.
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Vilan A, Grangeia A, Ribeiro JM, Cilio MR, de Vries LS. Distinctive Amplitude-Integrated EEG Ictal Pattern and Targeted Therapy with Carbamazepine in KCNQ2 and KCNQ3 Neonatal Epilepsy: A Case Series. Neuropediatrics 2024; 55:32-41. [PMID: 37827512 DOI: 10.1055/a-2190-9521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
BACKGROUND Carbamazepine (CBZ) is effective in treating KCNQ2/3-related seizures, which may present with a distinctive amplitude-integrated electroencephalography (aEEG) pattern. OBJECTIVE To assess how improved recognition of the distinctive aEEG ictal pattern associated with KCNQ2/3 variants has enabled early and effective targeted therapy with CBZ. METHODS Retrospective descriptive study of five neonates with KCNQ2/3 pathogenic gene variants admitted at a level 3 neonatal intensive care unit (NICU) over an 8-year period. RESULTS The distinctive ictal aEEG pattern was recognized in four neonates after an average of 61.5 hours (minimum 12 hours, maximum 120 hours) from the first electroclinical seizure and prompted the use of CBZ that was effective in all. The two most recently diagnosed patients could avoid polytherapy as they received CBZ as the first and second antiseizure medication, respectively. Three out of five patients with continuous normal voltage (CNV), sleep-wake cycling (SWC), and shorter postictal suppression had normal neurodevelopmental outcome. Regarding the remaining two infants, one was not trialed with CBZ and had a high seizure burden, both presented with a prolonged postictal suppression, no SWC, and had moderate-to-severe developmental delay. Genetic results became available after the neonatal period in all but one of the infants, who had a prenatal diagnosis. CONCLUSION Recognition of the distinctive ictal aEEG pattern in the NICU allowed early and effective targeted therapy with CBZ in four neonates, well before genetic results became available. Furthermore, a CNV background pattern with SWC and short postictal suppression were associated with normal developmental outcomes.
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Affiliation(s)
- Ana Vilan
- Department of Neonatology, Centro Hospitalar São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Ana Grangeia
- Department of Genetics, Centro Hospitalar São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - José Mendes Ribeiro
- Laboratory of Clinical Neurophysiology, Department of Neurology, Centro Hospitalar Vila Nova de Gaia e Espinho, Porto, Portugal
| | - Maria Roberta Cilio
- Division of Pediatric Neurology, Department of Pediatrics, Catholic University of Louvain, Brussels, Belgium
| | - Linda S de Vries
- Department of Neonatology, Leiden University Medical Center, Leiden, The Netherlands
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Jiang S, Liu B, Lin K, Li L, Li R, Tan S, Zhang X, Jiang L, Ni H, Wang Y, Ding H, Hu J, Qian H, Ge R. Impacted spike frequency adaptation associated with reduction of KCNQ2/3 exacerbates seizure activity in temporal lobe epilepsy. Hippocampus 2024; 34:58-72. [PMID: 38049972 DOI: 10.1002/hipo.23587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 09/21/2023] [Accepted: 10/28/2023] [Indexed: 12/06/2023]
Abstract
Numerous epilepsy-related genes have been identified in recent decades by unbiased genome-wide screens. However, the available druggable targets for temporal lobe epilepsy (TLE) remain limited. Furthermore, a substantial pool of candidate genes potentially applicable to TLE therapy awaits further validation. In this study, we reveal the significant role of KCNQ2 and KCNQ3, two M-type potassium channel genes, in the onset of seizures in TLE. Our investigation began with a quantitative analysis of two publicly available TLE patient databases to establish a correlation between seizure onset and the downregulated expression of KCNQ2/3. We then replicated these pathological changes in a pilocarpine seizure mouse model and observed a decrease in spike frequency adaptation due to the affected M-currents in dentate gyrus granule neurons. In addition, we performed a small-scale simulation of the dentate gyrus network and confirmed that the impaired spike frequency adaptation of granule cells facilitated epileptiform activity throughout the network. This, in turn, resulted in prolonged seizure duration and reduced interictal intervals. Our findings shed light on an underlying mechanism contributing to ictogenesis in the TLE hippocampus and suggest a promising target for the development of antiepileptic drugs.
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Affiliation(s)
- Shicheng Jiang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Bei Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Kaiwen Lin
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lianjun Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Rongrong Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Shuo Tan
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Xinyu Zhang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lei Jiang
- Department of General Surgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, China
| | - Hong Ni
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Yuanyuan Wang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Haihu Ding
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
| | - Jing Hu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Qian
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Rongjing Ge
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
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Iftimovici A, Charmet A, Desnous B, Ory A, Delorme R, Coutton C, Devillard F, Milh M, Maruani A. Familial KCNQ2 mutation: a psychiatric perspective. Psychiatr Genet 2024; 34:24-27. [PMID: 38108335 PMCID: PMC10766091 DOI: 10.1097/ypg.0000000000000360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
KCNQ2 mutations are a common cause of early-onset epileptic syndromes. They are associated with heterogeneous developmental profiles, from mild to severe cognitive and social impairments that need better characterization. We report a case of an inherited KCNQ2 mutation due to a deletion c.402delC in a heterozygous state, in the exon 3 of the KCNQ2 gene. A 5-year-old boy presented a cluster of sudden-onset generalized tonic-clonic seizures at three months of age, after an unremarkable postnatal period. Multiplex ligation-dependent probe amplification identified a familial mutation after an investigation in the family revealed that this mutation was present on the father's side. The patient was diagnosed with autism and intellectual deficiency in a context of KCNQ2 -encephalopathy. We describe his clinical features in light of current literature. This report highlights the importance of appropriate genetic counseling and psychiatric assessment in planning the medical and social follow-up of a disorder with complex socio-behavioral features.
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Affiliation(s)
- Anton Iftimovici
- Université Paris Cité, Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, “Physiopathology of psychiatric disorders” team
- GHU-Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne
| | - Angeline Charmet
- Department of Child and Adolescent Psychiatry, Robert Debré Hospital, APHP, Paris
| | - Béatrice Desnous
- Aix Marseille University, Department of pediatric neurology, La Timone Children’s Hospital, Marseille
| | - Ana Ory
- Department of Child and Adolescent Psychiatry, Robert Debré Hospital, APHP, Paris
| | - Richard Delorme
- Department of Child and Adolescent Psychiatry, Robert Debré Hospital, APHP, Paris
| | - Charles Coutton
- Laboratoire de Génétique Chromosomique, Service de Génétique, Génomique et Procréation, Centre Hospitalier Universitaire Grenoble-Alpes, Université Grenoble-Alpes, Grenoble, France
| | - Françoise Devillard
- Laboratoire de Génétique Chromosomique, Service de Génétique, Génomique et Procréation, Centre Hospitalier Universitaire Grenoble-Alpes, Université Grenoble-Alpes, Grenoble, France
| | - Mathieu Milh
- Aix Marseille University, Department of pediatric neurology, La Timone Children’s Hospital, Marseille
| | - Anna Maruani
- Department of Child and Adolescent Psychiatry, Robert Debré Hospital, APHP, Paris
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Bayat A, Iavarone S, Miceli F, Jakobsen AV, Johannesen KM, Nikanorova M, Ploski R, Szymanska K, Flamini R, Cooper EC, Weckhuysen S, Taglialatela M, Møller RS. Phenotypic and functional assessment of two novel KCNQ2 gain-of-function variants Y141N and G239S and effects of amitriptyline treatment. Neurotherapeutics 2024; 21:e00296. [PMID: 38241158 PMCID: PMC10903081 DOI: 10.1016/j.neurot.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 01/21/2024] Open
Abstract
While loss-of-function (LoF) variants in KCNQ2 are associated with a spectrum of neonatal-onset epilepsies, gain-of-function (GoF) variants cause a more complex phenotype that precludes neonatal-onset epilepsy. In the present work, the clinical features of three patients carrying a de novo KCNQ2 Y141N (n = 1) or G239S variant (n = 2) respectively, are described. All three patients had a mild global developmental delay, with prominent language deficits, and strong activation of interictal epileptic activity during sleep. Epileptic seizures were not reported. The absence of neonatal seizures suggested a GoF effect and prompted functional testing of the variants. In vitro whole-cell patch-clamp electrophysiological experiments in Chinese Hamster Ovary cells transiently-transfected with the cDNAs encoding Kv7.2 subunits carrying the Y141N or G239S variants in homomeric or heteromeric configurations with Kv7.2 subunits, revealed that currents from channels incorporating mutant subunits displayed increased current densities and hyperpolarizing shifts of about 10 mV in activation gating; both these functional features are consistent with an in vitro GoF phenotype. The antidepressant drug amitriptyline induced a reversible and concentration-dependent inhibition of current carried by Kv7.2 Y141N and G239S mutant channels. Based on in vitro results, amitriptyline was prescribed in one patient (G239S), prompting a significant improvement in motor, verbal, social, sensory and adaptive behavior skillsduring the two-year-treatment period. Thus, our results suggest that KCNQ2 GoF variants Y141N and G239S cause a mild DD with prominent language deficits in the absence of neonatal seizures and that treatment with the Kv7 channel blocker amitriptyline might represent a potential targeted treatment for patients with KCNQ2 GoF variants.
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Affiliation(s)
- Allan Bayat
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark; Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Stefano Iavarone
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Anne V Jakobsen
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department of Genetics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Marina Nikanorova
- Department of Pediatrics, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark
| | - Rafal Ploski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Krystyna Szymanska
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland
| | | | - Edward C Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston TX, USA
| | - Sarah Weckhuysen
- Applied and Translational Genomics Group, VIB-Center for Molecular Neurology, VIB, University of Antwerp, Antwerp, Belgium; Neurology Department, University Hospital Antwerp, Antwerp, Belgium; Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium; μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Filadelfia, Dianalund, Denmark; Department for Regional Health Research, University of Southern Denmark, Odense, Denmark
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.
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Huang Z, Liu B, Xiao T, Wang Y, Lu Y, Hu L, Cheng G, Li Z, Wang L, Zhang R, Wang J, Cao Y, Dong X, Yang L, Zhou W. Neurodevelopmental Outcomes Prediction in Newborns with Seizures Caused by KCNQ2 Gene Defects. Neonatology 2023; 121:178-186. [PMID: 38043515 DOI: 10.1159/000534605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 09/29/2023] [Indexed: 12/05/2023]
Abstract
INTRODUCTION Pathogenic variant in the KCNQ2 gene is a common genetic etiology of neonatal convulsion. However, it remains a question in KCNQ2-related disorders that who will develop into atypical developmental outcomes. METHODS We established a prediction model for the neurodevelopmental outcomes of newborns with seizures caused by KCNQ2 gene defects based on the Gradient Boosting Machine (GBM) model with a training set obtained from the Human Gene Mutation Database (HGMD, public training dataset). The features used in the prediction model were, respectively, based on clinical features only and optimized features. The validation set was obtained from the China Neonatal Genomes Project (CNGP, internal validation dataset). RESULTS With the HGMD training set, the prediction results showed that the area under the receiver-operating characteristic curve (AUC) for predicting atypical developmental outcomes was 0.723 when using clinical features only and was improved to 0.986 when using optimized features, respectively. In feature importance ranking, both variants pathogenicity and protein functional/structural features played an important role in the prediction model. For the CNGP validation set, the AUC was 0.596 when using clinical features only and was improved to 0.736 when using optimized features. CONCLUSION In our study, functional/structural features and variant pathogenicity have higher feature importance compared with clinical information. This prediction model for the neurodevelopmental outcomes of newborns with seizures caused by KCNQ2 gene defects is a promising alternative that could prove to be valuable in clinical practice.
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Affiliation(s)
- Zhelan Huang
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Bo Liu
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
| | - Tiantian Xiao
- Department of Neonatology, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yaqiong Wang
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
| | - Yulan Lu
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
| | - Liyuan Hu
- Division of Neonatology, Key Laboratory of Birth Defects, Children's Hospital of Fudan University, Shanghai, China
| | - Guoqiang Cheng
- Division of Neonatology, Key Laboratory of Birth Defects, Children's Hospital of Fudan University, Shanghai, China
| | - Zhihua Li
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Laishuan Wang
- Division of Neonatology, Key Laboratory of Birth Defects, Children's Hospital of Fudan University, Shanghai, China
| | - Rong Zhang
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Jin Wang
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Yun Cao
- Division of Neonatology, Children's Hospital of Fudan University, Shanghai, China
| | - Xinran Dong
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
| | - Lin Yang
- Department of Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University, Shanghai, China
| | - Wenhao Zhou
- Center for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
- Division of Neonatology, Key Laboratory of Birth Defects, Children's Hospital of Fudan University, Shanghai, China
- Children's Hospital of Fudan University, Xiamen Children's Hospital, Shanghai, China
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10
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Falsaperla R, Criscione R, Cimino C, Pisani F, Ruggieri M. KCNQ2-Related Epilepsy: Genotype-Phenotype Relationship with Tailored Antiseizure Medication (ASM)-A Systematic Review. Neuropediatrics 2023; 54:297-307. [PMID: 36948217 DOI: 10.1055/a-2060-4576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
BACKGROUND Autosomal dominant mutations of the KCNQ2 gene can cause two epileptic disorders: benign familial neonatal seizures (BFNS) and developmental epileptic encephalopathy (DEE). This systematic review aims to identify the best reported therapy for these patients, relating to phenotype, neurodevelopmental outcome, and an eventual correlation between phenotype and genotype. METHODS We searched on PubMed using the search terms "KCNQ2" AND "therapy" and "KCNQ2" AND "treatment"; we found 304 articles. Of these, 29 met our criteria. We collected the data from 194 patients. All 29 articles were retrospective studies. RESULTS In all, 104 patients were classified as DEE and 90 as BFNS. After treatment began, 95% of BFNS patients became seizure free, whereas the seizures stopped only in 73% of those with DEE. Phenobarbital and sodium channel blockers were the most used treatment in BFNS. Most of the DEE patients (95%) needed polytherapy for seizure control and even that did not prevent subsequent developmental impairment (77%).Missense mutations were discovered in 96% of DEE patients; these were less common in BFNS (50%), followed by large deletion (16%), truncation (16%), splice donor site (10%), and frameshift (7%). CONCLUSION Phenobarbital or carbamazepine appears to be the most effective antiseizure medication for children with a "benign" variant. On the contrary, polytherapy is often needed for DEE patients, even if it does not seem to improve neurological outcomes. In DEE patients, most mutations were located in S4 and S6 helix, which could serve as a potential target for the development of more specific treatment in the future.
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Affiliation(s)
- Raffaele Falsaperla
- Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico "Rodolico-San Marco", San Marco Hospital, University of Catania, Catania, Italy
- Unit of Clinical Paediatrics, Azienda Ospedaliero-Universitaria Policlinico, "Rodolico-San Marco", San Marco Hospital, Catania, Italy
| | - Roberta Criscione
- Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico "Rodolico-San Marco", Postgraduate Training Program in Pediatrics, University of Catania, Catania, Italy
| | - Carla Cimino
- Neonatal Intensive Care Unit and Neonatal Accompaniment Unit, Azienda Ospedaliero-Universitaria Policlinico "Rodolico-San Marco", San Marco Hospital, University of Catania, Catania, Italy
| | - Francesco Pisani
- Child Neuropsychiatry Unit, Human Neuroscience Department, Sapienza University of Rome, Italy
| | - Martino Ruggieri
- Unit of Clinical Pediatrics, Department of Clinical and Experimental Medicine, University of Catania, AOU "Policlinico", PO "G. Rodolico", Catania, Italy
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11
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Borggraefe I, Wagner M. Precision Therapy in KCNQ2-Related Epilepsy. Neuropediatrics 2023; 54:295-296. [PMID: 37722392 DOI: 10.1055/s-0043-1772667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Affiliation(s)
- Ingo Borggraefe
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, Ludwig Maximilian University Munich, Munich, Germany
- Comprehensive Epilepsy Center for Children and Adolescents, University Hospital, Ludwig Maximilians University Munich, Munich, Germany
| | - Matias Wagner
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, Ludwig Maximilian University Munich, Munich, Germany
- Institute of Neurogenomics, Helmholtz Centrum, Munich, Germany
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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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13
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Stewart R, Gadoud C, Krawczyk J, McInerney V, O'Brien T, Shen S, Allen NM. Generation of three induced pluripotent stem cell lines from a patient with KCNQ2 developmental and epileptic encephalopathy as a result of the pathogenic variant c.881C > T; p.Ala294Val (NUIGi059-A, NUIGi059-B, NUIGi059-C) and 3 healthy controls (NUIGi060-A, NUIGi060-B, NUIGi060-C). Stem Cell Res 2023; 71:103191. [PMID: 37659345 DOI: 10.1016/j.scr.2023.103191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/04/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are a group of severe, early-onset epilepsies which are often caused by genetic mutations in ion channels. Mutations in KCNQ2, which encodes the voltage-gated potassium channel Kv7.2, is known to cause DEE. Here, we generated three iPSC lines from dermal fibroblasts of a 5 year-old male patient with the KCNQ2 c.881C > T (p.Ala294Val) pathogenic heterozygous variant and three iPSC lines from a healthy sibling control. These iPSC lines have been validated by SNP karyotyping, STR analysis, expression of pluripotent genes, the capacity to differentiate into three germ layers and confirmation of the mutation in the patient.
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Affiliation(s)
- Rachel Stewart
- Regenerative Medicine Institute, School of Medicine, University of Galway, Ireland; Department of Paediatrics, School of Medicine, University of Galway, Ireland.
| | - Cloe Gadoud
- Regenerative Medicine Institute, School of Medicine, University of Galway, Ireland
| | - Janusz Krawczyk
- Department of Haematology, Galway University Hospital, Ireland
| | | | - Timothy O'Brien
- Regenerative Medicine Institute, School of Medicine, University of Galway, Ireland; Confucius Institute of Chinese and Regenerative Medicine, University of Galway, Ireland
| | - Sanbing Shen
- Regenerative Medicine Institute, School of Medicine, University of Galway, Ireland; FutureNeuro Research Centre, Royal College of Surgeons in Ireland, Dublin D02, Ireland; Confucius Institute of Chinese and Regenerative Medicine, University of Galway, Ireland.
| | - Nicholas M Allen
- Department of Paediatrics, School of Medicine, University of Galway, Ireland.
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14
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Dirkx N, Weuring WJ, De Vriendt E, Smal N, van de Vondervoort J, van 't Slot R, Koetsier M, Zonnekein N, De Pooter T, Weckhuysen S, Koeleman BPC. Increased prime edit rates in KCNQ2 and SCN1A via single nicking all-in-one plasmids. BMC Biol 2023; 21:156. [PMID: 37443005 PMCID: PMC10347817 DOI: 10.1186/s12915-023-01646-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/07/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND Prime editing (PE) is the most recent gene editing technology able to introduce targeted alterations to the genome, including single base pair changes, small insertions, and deletions. Several improvements to the PE machinery have been made in the past few years, and these have been tested in a range of model systems including immortalized cell lines, stem cells, and animal models. While double nicking RNA (dncRNA) PE systems PE3 and PE5 currently show the highest editing rates, they come with reduced accuracy as undesired indels or SNVs arise at edited loci. Here, we aimed to improve single ncRNA (sncRNA) systems PE2 and PE4max by generating novel all-in-one (pAIO) plasmids driven by an EF-1α promoter, which is especially suitable for human-induced pluripotent stem cell (hiPSC) models. RESULTS pAIO-EF1α-PE2 and pAIO-EF1α-PE4max were used to edit the voltage gated potassium channel gene KCNQ2 and voltage gated sodium channel gene SCN1A. Two clinically relevant mutations were corrected using pAIO-EF1α-PE2 including the homozygous truncating SCN1A R612* variant in HEK293T cells and the heterozygous gain-of-function KCNQ2 R201C variant in patient-derived hiPSC. We show that sncRNA PE yielded detectable editing rates in hiPSC ranging between 6.4% and 9.8%, which was further increased to 41% after a GFP-based fluorescence-activated cell sorting (FACS) cell sorting step. Furthermore, we show that selecting the high GFP expressing population improved editing efficiencies up to 3.2-fold compared to the low GFP expressing population, demonstrating that not only delivery but also the number of copies of the PE enzyme and/or pegRNA per cell are important for efficient editing. Edit rates were not improved when an additional silent protospacer-adjacent motif (PAM)-removing alteration was introduced in hiPSC at the target locus. Finally, there were no genome-wide off-target effects using pAIO-EF1α-PE2 and no off-target editing activity near the edit locus highlighting the accuracy of snc prime editors. CONCLUSION Taken together, our study shows an improved efficacy of EF-1α driven sncRNA pAIO-PE plasmids in hiPSC reaching high editing rates, especially after FACS sorting. Optimizing these sncRNA PE systems is of high value when considering future therapeutic in vivo use, where accuracy will be extremely important.
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Affiliation(s)
- N Dirkx
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium.
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
| | - Wout J Weuring
- Department of Genetics, University Medical Center Utrecht, Utrecht, 3584 CX, The Netherlands.
| | - E De Vriendt
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
| | - N Smal
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - J van de Vondervoort
- Department of Genetics, University Medical Center Utrecht, Utrecht, 3584 CX, The Netherlands
| | - Ruben van 't Slot
- Department of Genetics, University Medical Center Utrecht, Utrecht, 3584 CX, The Netherlands
| | - M Koetsier
- Department of Genetics, University Medical Center Utrecht, Utrecht, 3584 CX, The Netherlands
| | - N Zonnekein
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Tim De Pooter
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
| | - S Weckhuysen
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - B P C Koeleman
- Department of Genetics, University Medical Center Utrecht, Utrecht, 3584 CX, The Netherlands
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15
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Zeng Z, Xu Y, Zhou Y, Su R, Tao L, Wang Z, Chen C, Chen W. Prognostic Analysis of KCNQ2 Patients via Combining EEG Deep Features and Machine Learning Classifiers. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38083766 DOI: 10.1109/embc40787.2023.10341098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Pathogenic variants of the KCNQ2 gene often induces neonatal epilepsy in clinical. For better treatment, infants with confirmed KCNQ2 pathogenic variant and epilepsy symptoms need to adjust their treatment plans according to the outcome after taking antiseizure medicines (ASMs). This process is often time-consuming and requires long-term follow-up, which undoubtedly causes unnecessary psychological and economic burdens. In this study, we investigate the feasibility to predict the outcome of KCNQ2 patients via Electroencephalogram (EEG). By using the combination of deep networks and classical classifiers, the abnormal brain pathological activities recorded in EEGs can be encoded into deep features and decoded into specific KCNQ2 outcomes, thus taking the advantage of both powerful feature extraction capability from deep networks and stronger classification ability from classical classifiers. Specifically, we acquire 10-channel EEG signals from 33 infants with KCNQ2 pathogenic variants after taking ASMs. Two well-trained models (Resnet-50 and Resnet-18) are employed to extract deep features from the EEG spectrums. We achieve an accuracy of 78.7% to predict the KCNQ2 outcome of each infant. To our best knowledge, this is the first study to employ potential EEG pathological differences to predict the outcomes of KCNQ2 patients. The investigation of automatic KCNQ2 outcome prediction may contribute to a more convenient diagnosis mechanism for KCNQ2 patients.
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16
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Oh H, Lee S, Oh Y, Kim S, Kim YS, Yang Y, Choi W, Yoo YE, Cho H, Lee S, Yang E, Koh W, Won W, Kim R, Lee CJ, Kim H, Kang H, Kim JY, Ku T, Paik SB, Kim E. Kv7/KCNQ potassium channels in cortical hyperexcitability and juvenile seizure-related death in Ank2-mutant mice. Nat Commun 2023; 14:3547. [PMID: 37321992 PMCID: PMC10272139 DOI: 10.1038/s41467-023-39203-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/01/2023] [Indexed: 06/17/2023] Open
Abstract
Autism spectrum disorders (ASD) represent neurodevelopmental disorders characterized by social deficits, repetitive behaviors, and various comorbidities, including epilepsy. ANK2, which encodes a neuronal scaffolding protein, is frequently mutated in ASD, but its in vivo functions and disease-related mechanisms are largely unknown. Here, we report that mice with Ank2 knockout restricted to cortical and hippocampal excitatory neurons (Ank2-cKO mice) show ASD-related behavioral abnormalities and juvenile seizure-related death. Ank2-cKO cortical neurons show abnormally increased excitability and firing rate. These changes accompanied decreases in the total level and function of the Kv7.2/KCNQ2 and Kv7.3/KCNQ3 potassium channels and the density of these channels in the enlengthened axon initial segment. Importantly, the Kv7 agonist, retigabine, rescued neuronal excitability, juvenile seizure-related death, and hyperactivity in Ank2-cKO mice. These results suggest that Ank2 regulates neuronal excitability by regulating the length of and Kv7 density in the AIS and that Kv7 channelopathy is involved in Ank2-related brain dysfunctions.
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Affiliation(s)
- Hyoseon Oh
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Yusang Oh
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Seongbin Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Young Seo Kim
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Yeji Yang
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanjiro, Ochang, Cheongju, Chungbuk, 28119, Korea
| | - Woochul Choi
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Ye-Eun Yoo
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Heejin Cho
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Seungjoon Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Esther Yang
- Department of Anatomy and Brain Korea 21 Graduate Program, Biomedical Science, College of Medicine, Korea University, Seoul, 02841, Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Woojin Won
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Ryunhee Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - C Justin Lee
- Center for Cognition and Sociality, IBS, Daejeon, 34126, Korea
| | - Hyun Kim
- Department of Anatomy and Brain Korea 21 Graduate Program, Biomedical Science, College of Medicine, Korea University, Seoul, 02841, Korea
| | - Hyojin Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Korea
| | - Jin Young Kim
- Research Center for Bioconvergence Analysis, Korea Basic Science Institute, 162 Yeongudanjiro, Ochang, Cheongju, Chungbuk, 28119, Korea
| | - Taeyun Ku
- Graduate School of Medical Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Se-Bum Paik
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141, Korea.
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea.
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17
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Kawano O, Saito T, Sumitomo N, Takeshita E, Shimizu-Motohashi Y, Nakagawa E, Mizuma K, Tanifuji S, Itai T, Miyatake S, Matsumoto N, Takahashi Y, Mizusawa H, Sasaki M. Skeletal anomaly and opisthotonus in early-onset epileptic encephalopathy with KCNQ2 abnormality. Brain Dev 2023; 45:231-236. [PMID: 36631315 DOI: 10.1016/j.braindev.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Heterozygous KCNQ2 variants cause benign familial neonatal seizures and early-onset epileptic encephalopathy in an autosomal dominant manner; the latter is called KCNQ2 encephalopathy. No case of KCNQ2 encephalopathy with arthrogryposis multiplex congenita has been reported. Furthermore, early-onset scoliosis and opisthotonus have not been documented as characteristics of KCNQ2 encephalopathy. CASE REPORT A male infant born with scoliosis and arthrogryposis multiplex congenita developed intractable epilepsy on the second day of life. At 4 months of age, he developed opisthotonus. The opisthotonus was refractory to medication in the beginning, and it spontaneously disappeared at 8 months of age. Whole-exome sequencing revealed a novel de novo heterozygous variant in KCNQ2, NM_172107.4:c.839A > C, p.(Tyr280Ser). CONCLUSIONS Early-onset scoliosis, arthrogryposis multiplex congenita, and opisthotonus may be related to KCNQ2 encephalopathy.
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Affiliation(s)
- Osamu Kawano
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Takashi Saito
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | - Noriko Sumitomo
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Eri Takeshita
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuko Shimizu-Motohashi
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Eiji Nakagawa
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Kanako Mizuma
- Department of Pediatrics, School of Medicine, Iwate Medical University, Iwate, Japan
| | - Sachiko Tanifuji
- Department of Pediatrics, School of Medicine, Iwate Medical University, Iwate, Japan
| | - Toshiyuki Itai
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Clinical Genetics Department, Yokohama City University Hospital, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hidehiro Mizusawa
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Masayuki Sasaki
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
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18
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Jing J, Dunbar C, Sonesra A, Chavez A, Park S, Yang R, Soh H, Lee M, Tzingounis AV, Cooper EC, Jiang X, Maheshwari A. Removal of KCNQ2 from parvalbumin-expressing interneurons improves anti-seizure efficacy of retigabine. Exp Neurol 2022; 355:114141. [PMID: 35691372 PMCID: PMC9899633 DOI: 10.1016/j.expneurol.2022.114141] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/18/2022] [Accepted: 06/06/2022] [Indexed: 02/07/2023]
Abstract
Anti-seizure drug (ASD) targets are widely expressed in both excitatory and inhibitory neurons. It remains unknown if the action of an ASD upon inhibitory neurons could counteract its beneficial effects on excitatory neurons (or vice versa), thereby reducing the efficacy of the ASD. Here, we examine whether the efficacy of the ASD retigabine (RTG) is altered after removal of the Kv7 potassium channel subunit KCNQ2, one of its drug targets, from parvalbumin-expressing interneurons (PV-INs). Parvalbumin-Cre (PV-Cre) mice were crossed with Kcnq2-floxed (Kcnq2fl/fl) mice to conditionally delete Kcnq2 from PV-INs. In these conditional knockout mice (cKO, PV-Kcnq2fl/fl), RTG (10 mg/kg, i.p.) significantly delayed the onset of either picrotoxin (PTX, 10 mg/kg, i.p)- or kainic acid (KA, 30 mg/kg, i.p.)-induced convulsive seizures compared to vehicle, while RTG was not effective in wild-type littermates (WT). Immunostaining for KCNQ2 and KCNQ3 revealed that both subunits were enriched at axon initial segments (AISs) of hippocampal CA1 PV-INs, and their specific expression was selectively abolished in cKO mice. Accordingly, the M-currents recorded from CA1 PV-INs and their sensitivity to RTG were significantly reduced in cKO mice. While the ability of RTG to suppress CA1 excitatory neurons in hippocampal slices was unchanged in cKO mice, its suppressive effect on the spike activity of CA1 PV-INs was significantly reduced compared with WT mice. In addition, the RTG-induced suppression on intrinsic membrane excitability of PV-INs in WT mice was significantly reduced in cKO mice. These findings suggest that preventing RTG from suppressing PV-INs improves its anticonvulsant effect.
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Affiliation(s)
- Junzhan Jing
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America
| | - Corrinne Dunbar
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Alina Sonesra
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ana Chavez
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Suhyeorn Park
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Ryan Yang
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Maxwell Lee
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Rd, Storrs, CT 06269, United States of America
| | - Edward C Cooper
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Street, Houston, TX 77030, United States of America.
| | - Atul Maheshwari
- Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, United States of America.
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19
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Hernandez CC, Tarfa RA, Miguel I Limcaoco J, Liu R, Mondal P, Hill C, Keith Duncan R, Tzounopoulos T, Stephenson CRJ, O'Meara MJ, Wipf P. Development of an automated screen for Kv7.2 potassium channels and discovery of a new agonist chemotype. Bioorg Med Chem Lett 2022; 71:128841. [PMID: 35671848 PMCID: PMC9469649 DOI: 10.1016/j.bmcl.2022.128841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/11/2022] [Accepted: 06/01/2022] [Indexed: 01/11/2023]
Abstract
To identify pore domain ligands on Kv7.2 potassium ion channels, we compared wild-type (WT) and W236L mutant Kv7.2 channels in a series of assays with previously validated and novel agonist chemotypes. Positive controls were retigabine, flupirtine, and RL-81; i.e. Kv7.2 channel activators that significantly shift voltage-dependent activation to more negative potentials (ΔV50) at 5 µM. We identified 6 new compounds that exhibited differential enhancing activity between WT and W236L mutant channels. Whole cell patch-clamp electrophysiology studies were conducted to identify Kv7.2. Kv7.2/3, Kv7.4, and Kv7.5 selectivity. Our results validate the SyncroPatch platform and establish new structure activity relationships (SAR). Specifically, in addition to selective Kv7.2, Kv7.2/3, Kv7.4. and Kv7.5 agonists, we identified a novel chemotype, ZK-21, a 4-aminotetrahydroquinoline that is distinct from any of the previously described Kv7 channel modifiers. Using flexible receptor docking, ZK-21 was predicted to be stabilized by W236 and bind perpendicular to retigabine, burying the benzyl carbamate group into a tunnel reaching the core of the pore domain.
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Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Rahilla A Tarfa
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jose Miguel I Limcaoco
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Ruiting Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Pravat Mondal
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Clare Hill
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - R Keith Duncan
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Thanos Tzounopoulos
- Department of Otolaryngology, Pittsburgh Hearing Research Center, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Corey R J Stephenson
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Matthew J O'Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15213, United States; School of Pharmacy, University of Eastern Finland, 70210 Kuopio, Finland
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20
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Li SB, Damonte VM, Chen C, Wang GX, Kebschull JM, Yamaguchi H, Bian WJ, Purmann C, Pattni R, Urban AE, Mourrain P, Kauer JA, Scherrer G, de Lecea L. Hyperexcitable arousal circuits drive sleep instability during aging. Science 2022; 375:eabh3021. [PMID: 35201886 PMCID: PMC9107327 DOI: 10.1126/science.abh3021] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sleep quality declines with age; however, the underlying mechanisms remain elusive. We found that hyperexcitable hypocretin/orexin (Hcrt/OX) neurons drive sleep fragmentation during aging. In aged mice, Hcrt neurons exhibited more frequent neuronal activity epochs driving wake bouts, and optogenetic activation of Hcrt neurons elicited more prolonged wakefulness. Aged Hcrt neurons showed hyperexcitability with lower KCNQ2 expression and impaired M-current, mediated by KCNQ2/3 channels. Single-nucleus RNA-sequencing revealed adaptive changes to Hcrt neuron loss in the aging brain. Disruption of Kcnq2/3 genes in Hcrt neurons of young mice destabilized sleep, mimicking aging-associated sleep fragmentation, whereas the KCNQ-selective activator flupirtine hyperpolarized Hcrt neurons and rejuvenated sleep architecture in aged mice. Our findings demonstrate a mechanism underlying sleep instability during aging and a strategy to improve sleep continuity.
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Affiliation(s)
- Shi-Bin Li
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Valentina Martinez Damonte
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Chong Chen
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gordon X. Wang
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
| | | | - Hiroshi Yamaguchi
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Wen-Jie Bian
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Carolin Purmann
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Reenal Pattni
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexander Eckehart Urban
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Philippe Mourrain
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- INSERM 1024, Ecole Normale Supérieure, Paris, France
| | - Julie A. Kauer
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Grégory Scherrer
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
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21
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Sheng ZF, Zhang H, Zheng P, Chen S, Gu Z, Zhou JJ, Phaup JG, Chang HM, Yeh ETH, Pan HL, Li DP. Impaired Kv7 channel activity in the central amygdala contributes to elevated sympathetic outflow in hypertension. Cardiovasc Res 2022; 118:585-596. [PMID: 33512443 PMCID: PMC8803073 DOI: 10.1093/cvr/cvab031] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 11/11/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Elevated sympathetic outflow is associated with primary hypertension. However, the mechanisms involved in heightened sympathetic outflow in hypertension are unclear. The central amygdala (CeA) regulates autonomic components of emotions through projections to the brainstem. The neuronal Kv7 channel is a non-inactivating voltage-dependent K+ channel encoded by KCNQ2/3 genes involved in stabilizing the neuronal membrane potential and regulating neuronal excitability. In this study, we investigated if altered Kv7 channel activity in the CeA contributes to heightened sympathetic outflow in hypertension. METHODS AND RESULTS The mRNA and protein expression levels of Kv7.2/Kv7.3 in the CeA were significantly reduced in spontaneously hypertensive rats (SHRs) compared with Wistar-Kyoto (WKY) rats. Lowering blood pressure with coeliac ganglionectomy in SHRs did not alter Kv7.2 and Kv7.3 channel expression levels in the CeA. Fluospheres were injected into the rostral ventrolateral medulla (RVLM) to retrogradely label CeA neurons projecting to the RVLM (CeA-RVLM neurons). Kv7 channel currents recorded from CeA-RVLM neurons in brain slices were much smaller in SHRs than in WKY rats. Furthermore, the basal firing activity of CeA-RVLM neurons was significantly greater in SHRs than in WKY rats. Bath application of specific Kv7 channel blocker 10, 10-bis (4-pyridinylmethyl)-9(10H)-anthracnose (XE-991) increased the excitability of CeA-RVLM neurons in WKY rats, but not in SHRs. Microinjection of XE-991 into the CeA increased arterial blood pressure (ABP) and renal sympathetic nerve activity (RSNA), while microinjection of Kv7 channel opener QO-58 decreased ABP and RSNA, in anaesthetized WKY rats but not SHRs. CONCLUSIONS Our findings suggest that diminished Kv7 channel activity in the CeA contributes to elevated sympathetic outflow in primary hypertension. This novel information provides new mechanistic insight into the pathogenesis of neurogenic hypertension.
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Affiliation(s)
- Zhao-Fu Sheng
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - Hua Zhang
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - PeiRu Zheng
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - Shanyan Chen
- Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - Zezong Gu
- Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - Jing-Jing Zhou
- Department of Anesthesiology and Perioperative Medicine, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
| | - Jeffery G Phaup
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
| | - Hui-Ming Chang
- Departments of Pharmacology and Toxicology and Internal Medicine, The University of Arkansas for Medical Sciences, 4301 West Markham St., Little Rock, AR 72205, USA
| | - Edward T H Yeh
- Departments of Pharmacology and Toxicology and Internal Medicine, The University of Arkansas for Medical Sciences, 4301 West Markham St., Little Rock, AR 72205, USA
| | - Hui-Lin Pan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas, MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
| | - De-Pei Li
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri, 1 Hospital Drive, Columbia, MO 65212, USA
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22
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Kim EC, Zhang J, Tang AY, Bolton EC, Rhodes JS, Christian-Hinman CA, Chung HJ. Spontaneous seizure and memory loss in mice expressing an epileptic encephalopathy variant in the calmodulin-binding domain of K v7.2. Proc Natl Acad Sci U S A 2021; 118:e2021265118. [PMID: 34911751 PMCID: PMC8713762 DOI: 10.1073/pnas.2021265118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2021] [Indexed: 11/18/2022] Open
Abstract
Epileptic encephalopathy (EE) is characterized by seizures that respond poorly to antiseizure drugs, psychomotor delay, and cognitive and behavioral impairments. One of the frequently mutated genes in EE is KCNQ2, which encodes the Kv7.2 subunit of voltage-gated Kv7 potassium channels. Kv7 channels composed of Kv7.2 and Kv7.3 are enriched at the axonal surface, where they potently suppress neuronal excitability. Previously, we reported that the de novo dominant EE mutation M546V in human Kv7.2 blocks calmodulin binding to Kv7.2 and axonal surface expression of Kv7 channels via their intracellular retention. However, whether these pathogenic mechanisms underlie epileptic seizures and behavioral comorbidities remains unknown. Here, we report conditional transgenic cKcnq2+/M547V mice, in which expression of mouse Kv7.2-M547V (equivalent to human Kv7.2-M546V) is induced in forebrain excitatory pyramidal neurons and astrocytes. These mice display early mortality, spontaneous seizures, enhanced seizure susceptibility, memory impairment, and repetitive behaviors. Furthermore, hippocampal pathology shows widespread neurodegeneration and reactive astrocytes. This study demonstrates that the impairment in axonal surface expression of Kv7 channels is associated with epileptic seizures, cognitive and behavioral deficits, and neuronal loss in KCNQ2-related EE.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Andy Y Tang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Eric C Bolton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Justin S Rhodes
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Catherine A Christian-Hinman
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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23
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Xu Y, Dou YL, Chen X, Dong XR, Wang XH, Wu BB, Cheng GQ, Zhou YF. Early initial video-electro-encephalography combined with variant location predict prognosis of KCNQ2-related disorder. BMC Pediatr 2021; 21:477. [PMID: 34711204 PMCID: PMC8555078 DOI: 10.1186/s12887-021-02946-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/07/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The clinical features of KCNQ2-related disorders range from benign familial neonatal seizures 1 to early infantile epileptic encephalopathy 7. The genotype-phenotypic association is difficult to establish. OBJECTIVE To explore potential factors in neonatal period that can predict the prognosis of neonates with KCNQ2-related disorder. METHODS Infants with KCNQ2-related disorder were retrospectively enrolled in our study in Children's Hospital of Fudan University in China from Jan 2015 to Mar 2020. All infants were older than age of 12 months at time of follow-up, and assessed by Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III) or Wechsler preschool and primary scale of intelligence-fourth edition (WPPSI-IV), then divided into three groups based on scores of BSID-III or WPPSI-IV: normal group, mild impairment group, encephalopathy group. We collected demographic variables, clinical characteristics, neuroimaging data. Considered variables include gender, gestational age, birth weight, age of the initial seizures, early interictal VEEG, variant location, delivery type. Variables predicting prognosis were identified using multivariate ordinal logistic regression analysis. RESULTS A total of 52 infants were selected in this study. Early interictal video-electro-encephalography (VEEG) (β = 2.77, 1.20 to 4.34, P = 0.001), and variant location (β = 2.77, 0.03 to 5.5, P = 0.048) were independent risk factors for prognosis. The worse the early interictal VEEG, the worse the prognosis. Patients with variants located in the pore-lining domain or S4 segment are more likely to have a poor prognosis. CONCLUSIONS The integration of early initial VEEG and variant location can predict prognosis. An individual whose KCNQ2 variant located in voltage sensor, the pore domain, with worse early initial VEEG background, often had an adverse outcome.
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Affiliation(s)
- Yan Xu
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, NO.399 Wanyuan Road, Minhang District, Shanghai, 201102, China
| | - Ya-Lan Dou
- Department of clinical Epidemiology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Xiang Chen
- Department of Neonatology, Children's Hospital of Fudan University, National Children's Medical Center, NO.399 Wanyuan Road, Minhang District, Shanghai, 201102, China
| | - Xin-Ran Dong
- Molecular Medical Center, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Xin-Hua Wang
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, NO.399 Wanyuan Road, Minhang District, Shanghai, 201102, China
| | - Bing-Bing Wu
- The Molecular Genetic Diagnosis Center, Shanghai Key Lab of Birth Defects, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Guo-Qiang Cheng
- Department of Neonatology, Children's Hospital of Fudan University, National Children's Medical Center, NO.399 Wanyuan Road, Minhang District, Shanghai, 201102, China.
| | - Yuan-Feng Zhou
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, NO.399 Wanyuan Road, Minhang District, Shanghai, 201102, China.
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Abstract
OBJECTIVE To determine the prevalence of and identify factors associated with gastrointestinal (GI) symptoms among children with channelopathy-associated developmental and epileptic encephalopathy (DEE). STUDY DESIGN Parents of 168 children with DEEs linked to SCN1A (n = 59), KCNB1 (n = 31), or KCNQ2 (n = 78) completed online CLIRINX surveys about their children's GI symptoms. Our analysis examined the prevalence, frequency, and severity of GI symptoms, as well as DEE type, functional mobility, feeding difficulties, ketogenic diet, antiseizure medication, autism spectrum disorder (ASD), and seizures. Statistical analyses included the χ2 test, Wilcoxon rank-sum analysis, and multiple logistic regression. RESULTS GI symptoms were reported in 92 of 168 patients (55%), among whom 63 of 86 (73%) reported daily or weekly symptoms, 29 of 92 (32%) had frequent or serious discomfort, and 13 of 91 (14%) had frequent or serious appetite disturbances as a result. The prevalence of GI symptoms varied across DEE cohorts with 44% of SCN1A-DEE patients, 35% of KCNB1-DEE patients, and 71% of KCNQ2-DEE patients reporting GI symptoms in the previous month. After adjustment for DEE type, current use of ketogenic diet (6% reported), and gastrostomy tube (13% reported) were both associated with GI symptoms in a statistically, but not clinically, significant manner (P < .05). Patient age, functional mobility, feeding difficulties, ASD, and seizures were not clearly associated with GI symptoms. Overall, no individual antiseizure medication was significantly associated with GI symptoms across all DEE cohorts. CONCLUSIONS GI symptoms are common and frequently severe in patients with DEE.
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Affiliation(s)
- Veronica C Beck
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Lori L Isom
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI; Department of Neurology, University of Michigan, Ann Arbor, MI; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Anne T Berg
- Division of Neurology, Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL; Department of Pediatrics, Northwestern Feinberg School of Medicine, Chicago, IL.
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25
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Ritter DM, Horn PS, Holland KD. In Silico Predictions of KCNQ Variant Pathogenicity in Epilepsy. Pediatr Neurol 2021; 118:48-54. [PMID: 33784504 PMCID: PMC8076079 DOI: 10.1016/j.pediatrneurol.2021.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 01/10/2021] [Accepted: 01/18/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Variants in KCNQ2 and KCNQ3 may cause benign neonatal familial seizures and early infantile epileptic encephalopathy. Previous reports suggest that in silico models cannot predict pathogenicity accurately enough for clinical use. Here we sought to establish a model to accurately predict the pathogenicity of KCNQ2 and KCNQ3 missense variants based on available in silico prediction models. METHODS ClinVar and gnomAD databases of reported KCNQ2 and KCNQ3 missense variants in patients with neonatal epilepsy were accessed and classified as benign, pathogenic, or of uncertain significance. Sensitivity, specificity, and classification accuracy for prediction of pathogenicity were determined and compared for 10 widely used prediction algorithms program. A mathematical model of the variants (KCNQ Index) was created using their amino acid location and prediction algorithm scores to improve prediction accuracy. RESULTS Using clinically characterized variants, the free online tool PROVEAN accurately predicted pathogenicity 92% of the time and the KCNQ Index had an accuracy of 96%. However, when including the gnomAD database as benign variants, only the KCNQ Index was able to predict pathogenicity with an accuracy greater than 90% (sensitivity = 93% and specificity = 98%). No model could accurately predict the phenotype of variants. CONCLUSION We show that KCNQ channel variant pathogenicity can be predicted by a novel KCNQ Index in neonatal epilepsy. However, more work is needed to accurately predict the patient's epilepsy phenotype from in silico algorithms.
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Affiliation(s)
- David M Ritter
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio.
| | - Paul S Horn
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Katherine D Holland
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
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26
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Millichap JJ, Harden CL, Dlugos DJ, French JA, Butterfield NN, Grayson C, Aycardi E, Pimstone SN. Capturing seizures in clinical trials of antiseizure medications for KCNQ2-DEE. Epilepsia Open 2021; 6:38-44. [PMID: 33681646 PMCID: PMC7918316 DOI: 10.1002/epi4.12466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 11/16/2022] Open
Abstract
Literature review of patients with KCNQ2 developmental and epileptic encephalopathy (KCNQ2-DEE) reveals, based on 16 reports including 139 patients, a clinical phenotype that includes age- and disease-specific stereotyped seizures. The typical seizure type of KCNQ2-DEE, focal tonic, starts within 0-5 days of life and is readily captured by video-electroencephalography VEEG for clinical and genetic diagnosis. After initial identification, KCNQ2-DEE seizures are clinically apparent and can be clearly identified without the use of EEG or VEEG. Therefore, we propose that the 2019 recommendations from the International League against Epilepsy (ILAE), the Pediatric Epilepsy Research Consortium (PERC), for capturing and recording seizures for clinical trials (Epilepsia Open, 4, 2019, 537) are suitable for use in KCNQ2-DEE‒associated antiseizure medicine (ASM) treatment trials. The ILAE/PERC consensus guidance states that a caregiver-maintained seizure diary, completed by caregivers who are trained to recognize seizures using within-patient historical recordings, accurately captures seizures prospectively in a clinical trial. An alternative approach historically endorsed by the Food and Drug Administration (FDA) compares seizure counts captured on VEEG before and after treatment. A major advantage of the ILAE/PERC strategy is that it expands the numbers of eligible patients who meet inclusion criteria of clinical trials while maintaining accurate seizure counts (Epilepsia Open, 4, 2019, 537). Three recent phase 3 pivotal pediatric trials investigating ASMs to treat syndromic seizures in patients as young as 2 years of age (N Engl J Med, 17, 2017, 699; Lancet, 21, 2020, 2243; Lancet, 17, 2018, 1085); and ongoing phase 2 open-label pediatric clinical trial that includes pediatric epileptic syndromes as young as 1 month of age (Am J Med Genet A, 176, 2018, 773), have already used caregiver-maintained seizure diaries successfully. For determining the outcome of a KCNQ2-DEE ASM treatment trial, the use of a seizure diary to count seizures by trained observers is feasible because the seizures of KCNQ2-DEE are clinically apparent. This strategy is supported by successful precedent in clinical trials in similar age groups and has the endorsement of the international pediatric epilepsy community.
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Affiliation(s)
- John J. Millichap
- Epilepsy Center and Division of NeurologyAnn & Robert H. Lurie Children’s Hospital of ChicagoChicagoILUSA
- Departments of Pediatrics and NeurologyNorthwestern University Feinberg School of MedicineChicagoILUSA
| | | | - Dennis J. Dlugos
- Children's Hospital of PhiladelphiaPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPAUSA
| | | | | | - Celene Grayson
- Xenon Pharmaceuticals, Inc.BurnabyBritish ColumbiaCanada
| | | | - Simon N. Pimstone
- Xenon Pharmaceuticals, Inc.BurnabyBritish ColumbiaCanada
- Division of General Internal MedicineUniversity of British ColumbiaBurnabyBritish ColumbiaCanada
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Li X, Zhang Q, Guo P, Fu J, Mei L, Lv D, Wang J, Lai D, Ye S, Yang H, Guo J. Molecular basis for ligand activation of the human KCNQ2 channel. Cell Res 2021; 31:52-61. [PMID: 32884139 PMCID: PMC7852908 DOI: 10.1038/s41422-020-00410-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/14/2020] [Indexed: 01/10/2023] Open
Abstract
The voltage-gated potassium channel KCNQ2 is responsible for M-current in neurons and is an important drug target to treat epilepsy, pain and several other diseases related to neuronal hyper-excitability. A list of synthetic compounds have been developed to directly activate KCNQ2, yet our knowledge of their activation mechanism is limited, due to lack of high-resolution structures. Here, we report cryo-electron microscopy (cryo-EM) structures of the human KCNQ2 determined in apo state and in complex with two activators, ztz240 or retigabine, which activate KCNQ2 through different mechanisms. The activator-bound structures, along with electrophysiology analysis, reveal that ztz240 binds at the voltage-sensing domain and directly stabilizes it at the activated state, whereas retigabine binds at the pore domain and activates the channel by an allosteric modulation. By accurately defining ligand-binding sites, these KCNQ2 structures not only reveal different ligand recognition and activation mechanisms, but also provide a structural basis for drug optimization and design.
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Affiliation(s)
- Xiaoxiao Li
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Qiansen Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Peipei Guo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Jie Fu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China
| | - Lianghe Mei
- Suzhou Institute of Drug Innovation, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 108 Yuxin Road, Suzhou, Jiangsu, 215123, China
| | - Dashuai Lv
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Jiangqin Wang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Dongwu Lai
- Department of Cardiology, Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Sheng Ye
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, 310058, China
- School of Life Sciences, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Huaiyu Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China.
| | - Jiangtao Guo
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.
- Department of Cardiology, Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China.
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28
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Lazo PA, García JL, Gómez-Puertas P, Marcos-Alcalde Í, Arjona C, Villarroel A, González-Sarmiento R, Fons C. Novel Dominant KCNQ2 Exon 7 Partial In-Frame Duplication in a Complex Epileptic and Neurodevelopmental Delay Syndrome. Int J Mol Sci 2020; 21:ijms21124447. [PMID: 32585800 PMCID: PMC7352878 DOI: 10.3390/ijms21124447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/23/2022] Open
Abstract
Complex neurodevelopmental syndromes frequently have an unknown etiology, in which genetic factors play a pathogenic role. This study utilizes whole-exome sequencing (WES) to examine four members of a family with a son presenting, since birth, with epileptic-like crises, combined with cerebral palsy, severe neuromotor and developmental delay, dystonic tetraparexia, axonal motor affectation, and hyper-excitability of unknown origin. The WES study detected within the patient a de novo heterozygous in-frame duplication of thirty-six nucleotides within exon 7 of the human KCNQ2 gene. This insertion duplicates the first twelve amino acids of the calmodulin binding site I. Molecular dynamics simulations of this KCNQ2 peptide duplication, modelled on the 3D structure of the KCNQ2 protein, suggest that the duplication may lead to the dysregulation of calcium inhibition of this protein function.
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Affiliation(s)
- Pedro A. Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
- Correspondence:
| | - Juan L. García
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
| | - Paulino Gómez-Puertas
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain; (P.G.-P.); (Í.M.-A.)
| | - Íñigo Marcos-Alcalde
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain; (P.G.-P.); (Í.M.-A.)
- Biosciences Research Institute, School of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain
| | - Cesar Arjona
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain; (C.A.); (C.F.)
- Instituto Pediátrico de Enfermedades Raras (IPER), Hospital Sant Joan de Déu, 08950 Barcelona, Spain
| | - Alvaro Villarroel
- Instituto de Biofísica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad del País Vasco, 48940 Bilbao, Spain;
| | - Rogelio González-Sarmiento
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 30007 Salamanca, Spain; (J.L.G.); (R.G.-S.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 30007 Salamanca, Spain
- Unidad de Genética Molecular, Departamento de Medicina, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Carmen Fons
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain; (C.A.); (C.F.)
- Neurology Department, Hospital Sant Joan de Déu, Sant Joan de Déu Research Institute and CIBERER, Instituto de Salud Carlos III, 08950 Barcelona, Spain
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29
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Zhang J, Kim EC, Chen C, Procko E, Pant S, Lam K, Patel J, Choi R, Hong M, Joshi D, Bolton E, Tajkhorshid E, Chung HJ. Identifying mutation hotspots reveals pathogenetic mechanisms of KCNQ2 epileptic encephalopathy. Sci Rep 2020; 10:4756. [PMID: 32179837 PMCID: PMC7075958 DOI: 10.1038/s41598-020-61697-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/02/2020] [Indexed: 11/08/2022] Open
Abstract
Kv7 channels are enriched at the axonal plasma membrane where their voltage-dependent potassium currents suppress neuronal excitability. Mutations in Kv7.2 and Kv7.3 subunits cause epileptic encephalopathy (EE), yet the underlying pathogenetic mechanism is unclear. Here, we used novel statistical algorithms and structural modeling to identify EE mutation hotspots in key functional domains of Kv7.2 including voltage sensing S4, the pore loop and S6 in the pore domain, and intracellular calmodulin-binding helix B and helix B-C linker. Characterization of selected EE mutations from these hotspots revealed that L203P at S4 induces a large depolarizing shift in voltage dependence of Kv7.2 channels and L268F at the pore decreases their current densities. While L268F severely reduces expression of heteromeric channels in hippocampal neurons without affecting internalization, K552T and R553L mutations at distal helix B decrease calmodulin-binding and axonal enrichment. Importantly, L268F, K552T, and R553L mutations disrupt current potentiation by increasing phosphatidylinositol 4,5-bisphosphate (PIP2), and our molecular dynamics simulation suggests PIP2 interaction with these residues. Together, these findings demonstrate that each EE variant causes a unique combination of defects in Kv7 channel function and neuronal expression, and suggest a critical need for both prediction algorithms and experimental interrogations to understand pathophysiology of Kv7-associated EE.
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Affiliation(s)
- Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Congcong Chen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Shashank Pant
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Kin Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Jaimin Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Rebecca Choi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Mary Hong
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Dhruv Joshi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eric Bolton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
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30
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Abstract
Potassium channels form physical complexes with solute transporters in vivo, yet little is known about their range of possible signaling modalities and the underlying mechanisms. The KCNQ2/3 potassium channel, which generates neuronal M-current, is voltage-gated and its activity is also stimulated by binding of various small molecules. KCNQ2/3 forms reciprocally regulating complexes with sodium-coupled myo-inositol transporters (SMITs) in mammalian neurons. Here, we report that the neurotransmitter γ-aminobutyric acid (GABA) and other small molecules directly regulate myo-inositol transport in rat dorsal root ganglia, and by human SMIT1-KCNQ2/3 complexes in vitro, by inducing a distinct KCNQ2/3 pore conformation. Reciprocally, SMIT1 tunes KCNQ2/3 sensing of GABA and related metabolites. Ion permeation and mutagenesis studies suggest that SMIT1 and GABA similarly alter KCNQ2/3 pore conformation but via different KCNQ subunits and molecular mechanisms. KCNQ channels therefore act as chemosensors to enable co-assembled myo-inositol transporters to respond to diverse stimuli including neurotransmitters, metabolites and drugs.
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Affiliation(s)
- Rίan W Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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31
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Manville RW, Abbott GW. In silico re-engineering of a neurotransmitter to activate KCNQ potassium channels in an isoform-specific manner. Commun Biol 2019; 2:401. [PMID: 31701029 PMCID: PMC6825221 DOI: 10.1038/s42003-019-0648-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/10/2019] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated potassium (Kv) channel dysfunction causes a variety of inherited disorders, but developing small molecules that activate Kv channels has proven challenging. We recently discovered that the inhibitory neurotransmitter γ-aminobutyric acid (GABA) directly activates Kv channels KCNQ3 and KCNQ5. Here, finding that inhibitory neurotransmitter glycine does not activate KCNQs, we re-engineered it in silico to introduce predicted KCNQ-opening properties, screened by in silico docking, then validated the hits in vitro. Attaching a fluorophenyl ring to glycine optimized its electrostatic potential, converting it to a low-nM affinity KCNQ channel activator. Repositioning the phenyl ring fluorine and/or adding a methylsulfonyl group increased the efficacy of the re-engineered glycines and switched their target KCNQs. Combining KCNQ2- and KCNQ3-specific glycine derivatives synergistically potentiated KCNQ2/3 activation by exploiting heteromeric channel composition. Thus, in silico optimization and docking, combined with functional screening of only three compounds, facilitated re-engineering of glycine to develop several potent KCNQ activators.
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Affiliation(s)
- Rían W. Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA USA
| | - Geoffrey W. Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA USA
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32
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Kamate M, Detroja M. Uncommon Treatable Genetic Epileptic Encephalopathies. Indian Pediatr 2019; 56:427-428. [PMID: 31102386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Mahesh Kamate
- Department of Pediatric Neurology, KLE University's JN Medical College, Belgaum, India.
| | - Mayank Detroja
- Department of Pediatric Neurology, KLE University's JN Medical College, Belgaum, India
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33
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Okahata M, Wei AD, Ohta A, Kuhara A. Cold acclimation via the KQT-2 potassium channel is modulated by oxygen in Caenorhabditis elegans. Sci Adv 2019; 5:eaav3631. [PMID: 30775442 PMCID: PMC6365114 DOI: 10.1126/sciadv.aav3631] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Adaptive responses to external temperatures are essential for survival in changing environments. We show here that environmental oxygen concentration affects cold acclimation in Caenorhabditis elegans and that this response is regulated by a KCNQ-type potassium channel, KQT-2. Depending on culture conditions, kqt-2 mutants showed supranormal cold acclimation, caused by abnormal thermosensation in ADL chemosensory neurons. ADL neurons are responsive to temperature via transient receptor potential channels-OSM-9, OCR-2, and OCR-1-with OCR-1 negatively regulating ADL function. Similarly, KQT-2 and KQT-3 regulate ADL activity, with KQT-2 positively regulating ADL function. Abnormal cold acclimation and acute temperature responses of ADL neurons in kqt-2 mutants were suppressed by an oxygen-receptor mutation in URX coelomic sensory neurons, which are electrically connected to ADL via RMG interneurons. Likewise, low oxygen suppressed supranormal kqt-2 cold acclimation. These data thus demonstrate a simple neuronal circuit integrating two different sensory modalities, temperature and oxygen, that determines cold acclimation.
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Affiliation(s)
- Misaki Okahata
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
| | - Aguan D. Wei
- Center for Integrative Brain Research, Seattle Children’s Research Institute, 1900 Ninth Ave., Seattle, WA 98101, USA
| | - Akane Ohta
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe 658-8501, Japan
- Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
| | - Atsushi Kuhara
- Graduate School of Natural Science, Konan University, Kobe 658-8501, Japan
- Institute for Integrative Neurobiology, Konan University, Kobe 658-8501, Japan
- Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan
- AMED-PRIME, Japan Agency for Medical Research and Development, Tokyo 100-0004, Japan
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34
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Benetou C, Papailiou S, Maritsi D, Anagnostopoulou K, Kontos H, Vartzelis G. A novel de novo KCNQ2 mutation in a child with treatmentresistant early-onset epileptic encephalopathy. Turk J Pediatr 2019; 61:279-281. [PMID: 31951342 DOI: 10.24953/turkjped.2019.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Benetou C, Papailiou S, Maritsi D, Anagnostopoulou K, Kontos H, Vartzelis G. A novel de novo KCNQ2 mutation in a child with treatmentresistant early-onset epileptic encephalopathy. Turk J Pediatr 2019; 61: 279-281. Mutations in KCNQ2 gene, encoding for voltage-gated K+ channel subunit, may result in a wide spectrum of early-onset epileptic disorders. The phenotype of the disease varies from `benign familial neonatal seizures` to `severe epileptic encephalopathies`. In this report, we present a novel mutation [namely: c.683A > G (p.His228Arg)], as a presumable cause of severe infantile-onset neonatal seizures, in a 3-month old boy. The seizures have been poorly responsive to various pharmacological treatments, with phenytoin and carbamazepine presenting with the most favourable results so far. The study of our patient could help to further clarify the clinical manifestations of KCNQ2 mutations, revealing a previously unreported mutation.
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Affiliation(s)
- Christina Benetou
- 2nd Department of Pediatrics, 'P&A Kyriakou' Children's Hospital, Athens University, Athens
| | - Stavroula Papailiou
- 2nd Department of Pediatrics, 'P&A Kyriakou' Children's Hospital, Athens University, Athens
| | - Despoina Maritsi
- 2nd Department of Pediatrics, 'P&A Kyriakou' Children's Hospital, Athens University, Athens
| | | | - Harry Kontos
- Department of Molecular Genetics, Genomedica S.A., Piraeus, Greece
| | - Georgios Vartzelis
- 2nd Department of Pediatrics, 'P&A Kyriakou' Children's Hospital, Athens University, Athens
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35
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Abstract
Dravet syndrome is considered to be one of the most severe types of genetic epilepsy. Mutations in SCN1A gene have been found to be responsible for at least 80% of patients with Dravet syndrome, and 90% of these mutations arise de novo. The variable clinical phenotype is commonly observed among these patients with SCN1A mutations, suggesting that genetic modifiers may influence the phenotypic expression of Dravet syndrome. In the present study, we described the clinical, pathological, and molecular characteristics of 13 Han Chinese pedigrees clinically diagnosed with Dravet syndrome. By targeted-exome sequencing, bioinformatics analysis and Sanger sequencing verification, 11 variants were identified in SCN1A gene among 11 pedigrees including 7 missense mutations, 2 splice site mutations, and 2 frameshift mutations (9 novel variants and 2 reported mutations). Particularly, 2 of these Dravet syndrome patients with SCN1A variants also harbored SCN9A, KCNQ2, or SLC6A8 variants. In addition, 2 subjects were failed to detect any pathogenic mutations in SCN1A and other epilepsy-related genes. These data suggested that SCN1A variants account for about 84.6% of Dravet syndrome in our cohort. This study expanded the mutational spectrum for the SCN1A gene, and also provided clinical and genetic evidence for the hypothesis that genetic modifiers may contribute to the variable manifestation of Dravet syndrome patients with SCN1A mutations. Thus, targeted-exome sequencing will make it possible to detect the interactions of epilepsy-related genes and reveal their modification on the severity of SCN1A mutation-related Dravet syndrome.
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Affiliation(s)
- TieJia Jiang
- Department of Neurology, The Children's Hospital of Zhejiang University School of Medicine
| | - Yaping Shen
- Department of Neurology, The Children's Hospital of Zhejiang University School of Medicine
| | - Huai Chen
- Hangzhou Red Cross Hospital, Hangzhou, China
| | - Zhefeng Yuan
- Department of Neurology, The Children's Hospital of Zhejiang University School of Medicine
| | - Shanshan Mao
- Department of Neurology, The Children's Hospital of Zhejiang University School of Medicine
| | - Feng Gao
- Department of Neurology, The Children's Hospital of Zhejiang University School of Medicine
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36
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Saviola D, Chiari M, Battagliola E, Savi C, De Tanti A. Diagnostic work-up and rehabilitation of cerebral visual impairment in infancy: A case of epileptic perinatal encephalopathy due to KCNQ2-related channelopathy. J Pediatr Rehabil Med 2018; 11:133-137. [PMID: 28655139 DOI: 10.3233/prm-170440-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND There is evidence that channelopathies are the cause of many different neurological diseases. The epileptic perinatal encephalopathy due to mutation in the KCNQ2 gene is a rare disease involving severe tetraparesis and cerebral visual impairment. Diseases of this kind are associated with severe disability that involves multiple systems and requires accurate genetic diagnosis and early multidisciplinary care once clinical stability is reached. CASE REPORT We describe a case of a baby girl with KCNQ2 encephalopathy who came to our observation for rehabilitation at age 2 years and 6 months. CLINICAL REHABILITATION IMPACT We stress the importance of a correct clinical, pharmacological and visual diagnosis. Correct diagnosis made it possible to involve the baby girl and her care-giver in an early process of visual rehabilitation lasting 6 months, the effects of which proved to persist at follow-up after more than a year, making it possible to start a useful inter-professional rehabilitation plan.
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Bonham LW, Evans DS, Liu Y, Cummings SR, Yaffe K, Yokoyama JS. Neurotransmitter Pathway Genes in Cognitive Decline During Aging: Evidence for GNG4 and KCNQ2 Genes. Am J Alzheimers Dis Other Demen 2018; 33:153-165. [PMID: 29338302 PMCID: PMC6209098 DOI: 10.1177/1533317517739384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND/RATIONALE Experimental studies support the role of neurotransmitter genes in dementia risk, but human studies utilizing single variants in candidate genes have had limited success. METHODS We used the gene-based testing program Versatile Gene-based Association Study to assess whether aggregate variation across 6 neurotransmitter pathways influences risk of cognitive decline in 8159 cognitively normal elderly (≥65 years old) adults from 3 community-based cohorts. RESULTS Common genetic variation in GNG4 and KCNQ2 was associated with cognitive decline. In human brain tissue data sets, both GNG4 and KCNQ2 show higher expression in hippocampus relative to other brain regions; GNG4 expression decreases with advancing age. Both GNG4 and KCNQ2 show highest expression in fetal astrocytes. CONCLUSION Genetic variation analyses and gene expression data suggest that GNG4 and KCNQ2 may be associated with cognitive decline in normal aging. Gene-based testing of neurotransmitter pathways may confirm and reveal novel risk genes in future studies of healthy cognitive aging.
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Affiliation(s)
- Luke W. Bonham
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA, USA
| | - Daniel S. Evans
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
| | - Yongmei Liu
- Department of Epidemiology and Prevention, Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Steven R. Cummings
- California Pacific Medical Center Research Institute, San Francisco, CA, USA
| | - Kristine Yaffe
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
- Department of Veterans Affairs, San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
- Department of Psychiatry, University of California, San Francisco, CA, USA
| | - Jennifer S. Yokoyama
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA, USA
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38
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Štěrbová K, Laššuthová P, Perníková I, Beran M, Neupauerová J, Kršek P, Seeman P. KCNQ2 Mutation Explains the Etiology of Chloral Hydrate-Responsive Ohtahara Syndrome. Pediatr Neurol 2017; 67:e3-e4. [PMID: 28065823 DOI: 10.1016/j.pediatrneurol.2016.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 11/19/2022]
Affiliation(s)
- Katalin Štěrbová
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic
| | - Petra Laššuthová
- DNA Laboratory, Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic.
| | - Ivana Perníková
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic
| | - Michal Beran
- Department of Forensic Medicine, Bulovka Hospital, Prague, Czech Republic
| | - Jana Neupauerová
- DNA Laboratory, Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic
| | - Pavel Kršek
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic
| | - Pavel Seeman
- DNA Laboratory, Department of Child Neurology, 2nd Faculty of Medicine, Charles University and Motol Hospital, Prague, Czech Republic
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Ihara Y, Tomonoh Y, Deshimaru M, Zhang B, Uchida T, Ishii A, Hirose S. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations. PLoS One 2016; 11:e0150095. [PMID: 26910900 PMCID: PMC4766199 DOI: 10.1371/journal.pone.0150095] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/09/2016] [Indexed: 12/30/2022] Open
Abstract
The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63–100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine’s scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.
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Affiliation(s)
- Yukiko Ihara
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yuko Tomonoh
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Masanobu Deshimaru
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Bo Zhang
- Department of Biochemistry, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Taku Uchida
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
| | - Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
- * E-mail:
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Choveau FS, Zhang J, Bierbower SM, Sharma R, Shapiro MS. The Role of the Carboxyl Terminus Helix C-D Linker in Regulating KCNQ3 K+ Current Amplitudes by Controlling Channel Trafficking. PLoS One 2015; 10:e0145367. [PMID: 26692086 PMCID: PMC4687061 DOI: 10.1371/journal.pone.0145367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/01/2015] [Indexed: 12/18/2022] Open
Abstract
In the central and peripheral nervous system, the assembly of KCNQ3 with KCNQ2 as mostly heteromers, but also homomers, underlies “M-type” currents, a slowly-activating voltage-gated K+ current that plays a dominant role in neuronal excitability. KCNQ3 homomers yield much smaller currents compared to KCNQ2 or KCNQ4 homomers and KCNQ2/3 heteromers. This smaller current has been suggested to result either from divergent channel surface expression or from a pore that is more unstable in KCNQ3. Channel surface expression has been shown to be governed by the distal part of the C-terminus in which helices C and D are critical for channel trafficking and assembly. A sequence alignment of this region in KCNQ channels shows that KCNQ3 possesses a longer linker between helix C and D compared to the other KCNQ subunits. Here, we investigate the role of the extra residues of this linker on KCNQ channel expression. Deletion of these residues increased KCNQ3 current amplitudes. Total internal reflection fluorescence imaging and plasma membrane protein assays suggest that the increase in current is due to a higher surface expression of the channels. Conversely, introduction of the extra residues into the linker between helices C and D of KCNQ4 reduced current amplitudes by decreasing the number of KCNQ4 channels at the plasma membrane. Confocal imaging suggests a higher fraction of channels, which possess the extra residues of helix C-D linker, were retained within the endoplasmic reticulum. Such retention does not appear to lead to protein accumulation and activation of the unfolded protein response that regulates protein folding and maintains endoplasmic reticulum homeostasis. Taken together, we conclude that extra helix C-D linker residues play a role in KCNQ3 current amplitudes by controlling the exit of the channel from the endoplasmic reticulum.
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Affiliation(s)
- Frank S. Choveau
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Jie Zhang
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Sonya M. Bierbower
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Ramaswamy Sharma
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Mark S. Shapiro
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
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Hu C, Wang L, Wang H. [One case of early-onset epileptic encephalopathy caused by KCNQ2 gene nonsense mutation]. Zhonghua Er Ke Za Zhi 2015; 53:788-789. [PMID: 26758118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Samanta D, Ramakrishnaiah R, Willis E, Frye RE. Myoclonic epilepsy evolved into West syndrome: a patient with a novel de novo KCNQ2 mutation. Acta Neurol Belg 2015; 115:475-8. [PMID: 25092550 DOI: 10.1007/s13760-014-0344-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 07/16/2014] [Indexed: 10/24/2022]
Affiliation(s)
- Debopam Samanta
- Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA,
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He M, Tang BS, Li N, Mao X, Li J, Zhang JG, Xiao JJ, Wang J, Jiang H, Shen L, Guo JF, Xia K, Wang JL. Using a combination of whole-exome sequencing and homozygosity mapping to identify a novel mutation of SCARB2. Clin Genet 2014; 86:598-600. [PMID: 24620919 DOI: 10.1111/cge.12338] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 12/26/2013] [Accepted: 12/26/2013] [Indexed: 11/27/2022]
Affiliation(s)
- M He
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, P. R. China
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Blom SM, Rottländer M, Kehler J, Bundgaard C, Schmitt N, Jensen HS. From pan-reactive KV7 channel opener to subtype selective opener/inhibitor by addition of a methyl group. PLoS One 2014; 9:e100209. [PMID: 24956197 PMCID: PMC4067310 DOI: 10.1371/journal.pone.0100209] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/22/2014] [Indexed: 01/24/2023] Open
Abstract
The voltage-gated potassium channels of the KV7 family (KV7.1–5) play important roles in controlling neuronal excitability and are therefore attractive targets for treatment of CNS disorders linked to hyperexcitability. One of the main challenges in developing KV7 channel active drugs has been to identify compounds capable of discriminating between the neuronally expressed subtypes (KV7.2–5), aiding the identification of the subunit composition of KV7 currents in various tissues, and possessing better therapeutic potential for particular indications. By taking advantage of the structure-activity relationship of acrylamide KV7 channel openers and the effects of these compounds on mutant KV7 channels, we have designed and synthesized a novel KV7 channel modulator with a unique profile. The compound, named SMB-1, is an inhibitor of KV7.2 and an activator of KV7.4. SMB-1 inhibits KV7.2 by reducing the current amplitude and increasing the time constant for the slow component of the activation kinetics. The activation of KV7.4 is seen as an increase in the current amplitude and a slowing of the deactivation kinetics. Experiments studying mutant channels with a compromised binding site for the KV7.2–5 opener retigabine indicate that SMB-1 binds within the same pocket as retigabine for both inhibition of KV7.2 and activation of KV7.4. SMB-1 may serve as a valuable tool for KV7 channel research and may be used as a template for further design of better subtype selective KV7 channel modulators. A compound with this profile could hold novel therapeutic potential such as the treatment of both positive and cognitive symptoms in schizophrenia.
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Affiliation(s)
- Sigrid Marie Blom
- Division of Neuroscience Drug Discovery, H. Lundbeck A/S, Copenhagen, Denmark
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mario Rottländer
- Division of Discovery Chemistry and DMPK, H. Lundbeck A/S, Copenhagen, Denmark
| | - Jan Kehler
- Division of Discovery Chemistry and DMPK, H. Lundbeck A/S, Copenhagen, Denmark
| | | | - Nicole Schmitt
- Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Sindal Jensen
- Division of Neuroscience Drug Discovery, H. Lundbeck A/S, Copenhagen, Denmark
- * E-mail:
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Kato M. [Molecular genetics of intractable epilepsies]. No To Hattatsu 2014; 46:191-194. [PMID: 24902337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Tomonoh Y, Deshimaru M, Araki K, Miyazaki Y, Arasaki T, Tanaka Y, Kitamura H, Mori F, Wakabayashi K, Yamashita S, Saito R, Itoh M, Uchida T, Yamada J, Migita K, Ueno S, Kitaura H, Kakita A, Lossin C, Takano Y, Hirose S. The kick-in system: a novel rapid knock-in strategy. PLoS One 2014; 9:e88549. [PMID: 24586341 PMCID: PMC3929540 DOI: 10.1371/journal.pone.0088549] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 01/06/2014] [Indexed: 11/25/2022] Open
Abstract
Knock-in mouse models have contributed tremendously to our understanding of human disorders. However, generation of knock-in animals requires a significant investment of time and effort. We addressed this problem by developing a novel knock-in system that circumvents several traditional challenges by establishing stem cells with acceptor elements enveloping a particular genomic target. Once established, these acceptor embryonic stem (ES) cells are efficient at directionally incorporating mutated target DNA using modified Cre/lox technology. This is advantageous, because knock-ins are not restricted to one a priori selected variation. Rather, it is possible to generate several mutant animal lines harboring desired alterations in the targeted area. Acceptor ES cell generation is the rate-limiting step, lasting approximately 2 months. Subsequent manipulations toward animal production require an additional 8 weeks, but this delimits the full period from conception of the genetic alteration to its animal incorporation. We call this system a “kick-in” to emphasize its unique characteristics of speed and convenience. To demonstrate the functionality of the kick-in methodology, we generated two mouse lines with separate mutant versions of the voltage-dependent potassium channel Kv7.2 (Kcnq2): p.Tyr284Cys (Y284C) and p.Ala306Thr (A306T); both variations have been associated with benign familial neonatal epilepsy. Adult mice homozygous for Y284C, heretofore unexamined in animals, presented with spontaneous seizures, whereas A306T homozygotes died early. Heterozygous mice of both lines showed increased sensitivity to pentylenetetrazole, possibly due to a reduction in M-current in CA1 hippocampal pyramidal neurons. Our observations for the A306T animals match those obtained with traditional knock-in technology, demonstrating that the kick-in system can readily generate mice bearing various mutations, making it a suitable feeder technology toward streamlined phenotyping.
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Affiliation(s)
- Yuko Tomonoh
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Masanobu Deshimaru
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Kimi Araki
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Yasuhiro Miyazaki
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Tomoko Arasaki
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Yasuyoshi Tanaka
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Haruna Kitamura
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Fumiaki Mori
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Koichi Wakabayashi
- Department of Neuropathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Sayaka Yamashita
- Department of Physiology and Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Ryo Saito
- Department of Physiology and Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Masayuki Itoh
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Kodaira, Japan
| | - Taku Uchida
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Junko Yamada
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Keisuke Migita
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shinya Ueno
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hiroki Kitaura
- Brain Research Institute, Niigata University, Niigata, Japan
| | - Akiyoshi Kakita
- Brain Research Institute, Niigata University, Niigata, Japan
| | - Christoph Lossin
- Department of Neurology, School of Medicine, University of California Davis, Sacramento, California, United States of America
| | - Yukio Takano
- Department of Physiology and Pharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
- * E-mail:
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Abstract
The long QT syndrome (LQTS) is a rare hereditary disorder in which affected individuals have a possibility of ventricular tachyarrhythmia and sudden cardiac death. We investigated 62 LQTS (QTc ≥ 0.47 sec) and 19 family members whose genetic study revealed mutation of LQT gene. In the proband group, the modes of presentation were ECG abnormality (38.7%), aborted cardiac arrest (24.2%), and syncope or seizure (19.4%). Median age of initial symptom development was 10.5 yr. Genetic studies were performed in 61; and mutations were found in 40 cases (KCNQ1 in 19, KCNH2 in 10, SCN5A in 7, KCNJ2 in 3, and CACNA1C in 1). In the family group, the penetrance of LQT gene mutation was 57.9%. QTc was longer as patients had the history of syncope (P = 0.001), ventricular tachycardia (P = 0.017) and aborted arrest (P = 0.010). QTc longer than 0.508 sec could be a cut-off value for major cardiac events (sensitivity 0.806, specificity 0.600). Beta-blocker was frequently applied for treatment and had significant effects on reducing QTc (P = 0.007). Implantable cardioverter defibrillators were applied in 6 patients. Congenital LQTS is a potentially lethal disease. It shows various genetic mutations with low penetrance in Korean patients.
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Affiliation(s)
- Yun-Sik Lee
- Department of Pediatrics, Seoul National University Boramae Hospital, Seoul, Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Bo-Sang Kwon
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Gi-Beom Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Se-Il Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Eun-Jung Bae
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Sung-Sup Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Chung-Il Noh
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
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Ferrer T, Aréchiga-Figueroa IA, Shapiro MS, Tristani-Firouzi M, Sanchez-Chapula JA. Tamoxifen inhibition of kv7.2/kv7.3 channels. PLoS One 2013; 8:e76085. [PMID: 24086693 PMCID: PMC3782443 DOI: 10.1371/journal.pone.0076085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 08/21/2013] [Indexed: 11/18/2022] Open
Abstract
KCNQ genes encode five Kv7 K+ channel subunits (Kv7.1–Kv7.5). Four of these (Kv7.2–Kv7.5) are expressed in the nervous system. Kv7.2 and Kv7.3 are the principal molecular components of the slow voltage-gated M-channel, which regulates neuronal excitability. In this study, we demonstrate that tamoxifen, an estrogen receptor antagonist used in the treatment of breast cancer, inhibits Kv7.2/Kv7.3 currents heterologously expressed in human embryonic kidney HEK-293 cells. Current inhibition by tamoxifen was voltage independent but concentration-dependent. The IC50 for current inhibition was 1.68 ± 0.44 µM. The voltage-dependent activation of the channel was not modified. Tamoxifen inhibited Kv7.2 homomeric channels with a higher potency (IC50 = 0.74 ± 0.16 µM). The mutation Kv7.2 R463E increases phosphatidylinositol- 4,5-bisphosphate (PIP2) - channel interaction and diminished dramatically the inhibitory effect of tamoxifen compared with that for wild type Kv7.2. Conversely, the mutation Kv7.2 R463Q, which decreases PIP2 -channel interaction, increased tamoxifen potency. Similar results were obtained on the heteromeric Kv7.2 R463Q/Kv7.3 and Kv7.2 R463E/Kv7.3 channels, compared to Kv7.2/Kv7.3 WT. Overexpression of type 2A PI(4)P5-kinase (PIP5K 2A) significantly reduced tamoxifen inhibition of Kv7.2/Kv7.3 and Kv7.2 R463Q channels. Our results suggest that tamoxifen inhibited Kv7.2/Kv7.3 channels by interfering with PIP2-channel interaction because of its documented interaction with PIP2 and the similar effect of tamoxifen on various PIP2 sensitive channels.
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Affiliation(s)
- Tania Ferrer
- Unidad de Investigación “Carlos Méndez” del Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col. México
- * E-mail:
| | - Ivan Arael Aréchiga-Figueroa
- Unidad de Investigación “Carlos Méndez” del Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col. México
| | - Mark S. Shapiro
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Martin Tristani-Firouzi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Division of Pediatric Cardiology, University of Utah, Salt Lake City, Utah, United States of America
| | - José A. Sanchez-Chapula
- Unidad de Investigación “Carlos Méndez” del Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col. México
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Robbins J, Passmore GM, Abogadie FC, Reilly JM, Brown DA. Effects of KCNQ2 gene truncation on M-type Kv7 potassium currents. PLoS One 2013; 8:e71809. [PMID: 23977150 PMCID: PMC3748097 DOI: 10.1371/journal.pone.0071809] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/02/2013] [Indexed: 11/23/2022] Open
Abstract
The KCNQ2 gene product, Kv7.2, is a subunit of the M-channel, a low-threshold voltage-gated K+ channel that regulates mammalian and human neuronal excitability. Spontaneous mutations one of the KCNQ2 genes cause disorders of neural excitability such as Benign Familial Neonatal Seizures. However there appear to be no reports in which both human KCNQ2 genes are mutated. We therefore asked what happens to M-channel function when both KCNQ2 genes are disrupted. We addressed this using sympathetic neurons isolated from mice in which the KCNQ2 gene was truncated at a position corresponding to the second transmembrane domain of the Kv7.2 protein. Since homozygote KCNQ2−/− mice die postnatally, experiments were largely restricted to neurons from late embryos. Quantitative PCR revealed an absence of KCNQ2 mRNA in ganglia from KCNQ2−/− embryos but 100–120% increase of KCNQ3 and KCNQ5 mRNAs; KCNQ2+/− ganglia showed ∼30% less KCNQ2 mRNA than wild-type (+/+) ganglia but 40–50% more KCNQ3 and KCNQ5 mRNA. Neurons from KCNQ2−/− embryos showed a complete absence of M-current, even after applying the Kv7 channel enhancer, retigabine. Neurons from heterozygote KCNQ2+/− embryos had ∼60% reduced M-current. In contrast, M-currents in neurons from adult KCNQ2+/− mice were no smaller than those in neurons from wild-type mice. Measurements of tetraethylammonium block did not indicate an increased expression of Kv7.5-containing subunits, implying a compensatory increase in Kv7.2 expression from the remaining KCNQ2 gene. We conclude that mouse embryonic M-channels have an absolute requirement for Kv7.2 subunits for functionality, that the reduced M-channel activity in heterozygote KCNQ2+/− mouse embryos results primarily from a gene-dosage effect, and that there is a compensatory increase in Kv7.2 expression in adult mice.
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Affiliation(s)
- Jon Robbins
- Wolfson Centre for Age Related Disease, King's College London, London, United Kingdom
- * E-mail:
| | - Gayle M. Passmore
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Fe C. Abogadie
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Health Innovations Research Institute, Royal Melbourne Institute of Technology University, Victoria, Australia
| | - Joanne M. Reilly
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David A. Brown
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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50
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Zheng Q, Fang D, Liu M, Cai J, Wan Y, Han JS, Xing GG. Suppression of KCNQ/M (Kv7) potassium channels in dorsal root ganglion neurons contributes to the development of bone cancer pain in a rat model. Pain 2012; 154:434-448. [PMID: 23352759 DOI: 10.1016/j.pain.2012.12.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 11/05/2012] [Accepted: 12/06/2012] [Indexed: 01/11/2023]
Abstract
Bone cancer pain has a strong impact on the quality of life of patients, but is difficult to treat. Better understanding of the pathogenic mechanisms underlying bone cancer pain will likely lead to the development of more effective treatments. In the present study, we investigated whether inhibition of KCNQ/M channels contributed to the hyperexcitability of primary sensory neurons and to the pathogenesis of bone cancer pain. By using a rat model of bone cancer pain based on intratibial injection of MRMT-1 tumour cells, we documented a prominent decrease in expression of KCNQ2 and KCNQ3 proteins and a reduction of M-current density in small-sized dorsal root ganglia (DRG) neurons, which were associated with enhanced excitability of these DRG neurons and the hyperalgesic behaviours in bone cancer rats. Coincidently, we found that inhibition of KCNQ/M channels with XE-991 caused a robust increase in the excitability of small-sized DRG neurons and produced an obvious mechanical allodynia in normal rats. On the contrary, activation of the KCNQ/M channels with retigabine not only inhibited the hyperexcitability of these small DRG neurons, but also alleviated mechanical allodynia and thermal hyperalgesia in bone cancer rats, and all of these effects of retigabine could be blocked by KCNQ/M-channel antagonist XE-991. These results suggest that repression of KCNQ/M channels leads to the hyperexcitability of primary sensory neurons, which in turn causes bone cancer pain. Thus, suppression of KCNQ/M channels in primary DRG neurons plays a crucial role in the development of bone cancer pain.
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Affiliation(s)
- Qin Zheng
- Neuroscience Research Institute and Department of Neurobiology, Peking University, Beijing, PR China Key Laboratory for Neuroscience of the Ministry of Education and the Ministry of Public Health, Beijing, PR China
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