1
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Andrade P, Alves JM, Pereira P, Rubin CJ, Silva E, Sprehn CG, Enbody E, Afonso S, Faria R, Zhang Y, Bonino N, Duckworth JA, Garreau H, Letnic M, Strive T, Thulin CG, Queney G, Villafuerte R, Jiggins FM, Ferrand N, Andersson L, Carneiro M. Selection against domestication alleles in introduced rabbit populations. Nat Ecol Evol 2024; 8:1543-1555. [PMID: 38907020 DOI: 10.1038/s41559-024-02443-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 05/14/2024] [Indexed: 06/23/2024]
Abstract
Humans have moved domestic animals around the globe for thousands of years. These have occasionally established feral populations in nature, often with devastating ecological consequences. To understand how natural selection shapes re-adaptation into the wild, we investigated one of the most successful colonizers in history, the European rabbit. By sequencing the genomes of 297 rabbits across three continents, we show that introduced populations exhibit a mixed wild-domestic ancestry. We show that alleles that increased in frequency during domestication were preferentially selected against in novel natural environments. Interestingly, causative mutations for common domestication traits sometimes segregate at considerable frequencies if associated with less drastic phenotypes (for example, coat colour dilution), whereas mutations that are probably strongly maladaptive in nature are absent. Whereas natural selection largely targeted different genomic regions in each introduced population, some of the strongest signals of parallelism overlap genes associated with neuronal or brain function. This limited parallelism is probably explained by extensive standing genetic variation resulting from domestication together with the complex mixed ancestry of introduced populations. Our findings shed light on the selective and molecular mechanisms that enable domestic animals to re-adapt to the wild and provide important insights for the mitigation and management of invasive populations.
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Affiliation(s)
- Pedro Andrade
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal.
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal.
| | - Joel M Alves
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
- Palaeogenomics and Bio-Archaeology Research Network Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
| | - Paulo Pereira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Carl-Johan Rubin
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Institute of Marine Research, Bergen, Norway
| | - Eugénio Silva
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - C Grace Sprehn
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Erik Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA, USA
| | - Sandra Afonso
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
| | - Rui Faria
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
| | - Yexin Zhang
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Never Bonino
- Estación Experimental Bariloche, Instituto Nacional de Tecnología Agropecuaria, Casilla de Correo Bariloche, Argentina
| | - Janine A Duckworth
- Wildlife Ecology and Management Group, Manaaki Whenua - Landcare Research, Lincoln, New Zealand
- Invasive Animals Cooperative Research Centre, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Hervé Garreau
- GenPhySE, Université de Toulouse, Castanet-Tolosan, France
| | - Mike Letnic
- Centre for Ecosystem Science, School of BEES, University of New South Wales, Sydney, New South Wales, Australia
- Evolution and Ecology Research Centre, School of BEES, University of New South Wales, Sydney, New South Wales, Australia
| | - Tanja Strive
- Centre for Invasive Species Solutions, University of Canberra, Bruce, Australian Capital Territory, Australia
- Commonwealth Scientific and Industrial Research Organisation, Canberra, Australian Capital Territory, Australia
| | - Carl-Gustaf Thulin
- Department of Animal Biosciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Guillaume Queney
- ANTAGENE, Wildlife Genetics Laboratory, La Tour de Salvagny, France
| | | | | | - Nuno Ferrand
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- Department of Zoology, Faculty of Sciences, University of Johannesburg, Auckland Park, South Africa
| | - Leif Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
| | - Miguel Carneiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal.
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal.
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2
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Qu W, Lam M, McInvale JJ, Mares JA, Kwon S, Humala N, Mahajan A, Nguyen T, Jakubiak KA, Mun JY, Tedesco TG, Al-Dalahmah O, Hussaini SA, Sproul AA, Siegelin MD, De Jager PL, Canoll P, Menon V, Hargus G. Xenografted human iPSC-derived neurons with the familial Alzheimer's disease APP V717I mutation reveal dysregulated transcriptome signatures linked to synaptic function and implicate LINGO2 as a disease signaling mediator. Acta Neuropathol 2024; 147:107. [PMID: 38918213 PMCID: PMC11199265 DOI: 10.1007/s00401-024-02755-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/27/2024]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, and disease mechanisms are still not fully understood. Here, we explored pathological changes in human induced pluripotent stem cell (iPSC)-derived neurons carrying the familial AD APPV717I mutation after cell injection into the mouse forebrain. APPV717I mutant iPSCs and isogenic controls were differentiated into neurons revealing enhanced Aβ42 production, elevated phospho-tau, and impaired neurite outgrowth in APPV717I neurons. Two months after transplantation, APPV717I and control neural cells showed robust engraftment but at 12 months post-injection, APPV717I grafts were smaller and demonstrated impaired neurite outgrowth compared to controls, while plaque and tangle pathology were not seen. Single-nucleus RNA-sequencing of micro-dissected grafts, performed 2 months after cell injection, identified significantly altered transcriptome signatures in APPV717I iPSC-derived neurons pointing towards dysregulated synaptic function and axon guidance. Interestingly, APPV717I neurons showed an increased expression of genes, many of which are also upregulated in postmortem neurons of AD patients including the transmembrane protein LINGO2. Downregulation of LINGO2 in cultured APPV717I neurons rescued neurite outgrowth deficits and reversed key AD-associated transcriptional changes related but not limited to synaptic function, apoptosis and cellular senescence. These results provide important insights into transcriptional dysregulation in xenografted APPV717I neurons linked to synaptic function, and they indicate that LINGO2 may represent a potential therapeutic target in AD.
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Affiliation(s)
- Wenhui Qu
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Matti Lam
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Neurological Institute, Columbia University, 710 West 168th Street, New York, NY, USA
| | - Julie J McInvale
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Jason A Mares
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Neurological Institute, Columbia University, 710 West 168th Street, New York, NY, USA
| | - Sam Kwon
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Nelson Humala
- Department of Neurosurgery, Columbia University, New York, NY, USA
| | - Aayushi Mahajan
- Department of Neurosurgery, Columbia University, New York, NY, USA
| | - Trang Nguyen
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Kelly A Jakubiak
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Jeong-Yeon Mun
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Thomas G Tedesco
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Osama Al-Dalahmah
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Syed A Hussaini
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Andrew A Sproul
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Markus D Siegelin
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Philip L De Jager
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Neurological Institute, Columbia University, 710 West 168th Street, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA
| | - Vilas Menon
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Neurological Institute, Columbia University, 710 West 168th Street, New York, NY, USA.
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
| | - Gunnar Hargus
- Department of Pathology and Cell Biology, Presbyterian Hospital, Columbia University, 650W 168th Street, New York, NY, USA.
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
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3
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Kalm T, Schob C, Völler H, Gardeitchik T, Gilissen C, Pfundt R, Klöckner C, Platzer K, Klabunde-Cherwon A, Ries M, Syrbe S, Beccaria F, Madia F, Scala M, Zara F, Hofstede F, Simon MEH, van Jaarsveld RH, Oegema R, van Gassen KLI, Holwerda SJB, Barakat TS, Bouman A, van Slegtenhorst M, Álvarez S, Fernández-Jaén A, Porta J, Accogli A, Mancardi MM, Striano P, Iacomino M, Chae JH, Jang S, Kim SY, Chitayat D, Mercimek-Andrews S, Depienne C, Kampmeier A, Kuechler A, Surowy H, Bertini ES, Radio FC, Mancini C, Pizzi S, Tartaglia M, Gauthier L, Genevieve D, Tharreau M, Azoulay N, Zaks-Hoffer G, Gilad NK, Orenstein N, Bernard G, Thiffault I, Denecke J, Herget T, Kortüm F, Kubisch C, Bähring R, Kindler S. Etiological involvement of KCND1 variants in an X-linked neurodevelopmental disorder with variable expressivity. Am J Hum Genet 2024; 111:1206-1221. [PMID: 38772379 PMCID: PMC11179411 DOI: 10.1016/j.ajhg.2024.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/25/2024] [Accepted: 04/25/2024] [Indexed: 05/23/2024] Open
Abstract
Utilizing trio whole-exome sequencing and a gene matching approach, we identified a cohort of 18 male individuals from 17 families with hemizygous variants in KCND1, including two de novo missense variants, three maternally inherited protein-truncating variants, and 12 maternally inherited missense variants. Affected subjects present with a neurodevelopmental disorder characterized by diverse neurological abnormalities, mostly delays in different developmental domains, but also distinct neuropsychiatric signs and epilepsy. Heterozygous carrier mothers are clinically unaffected. KCND1 encodes the α-subunit of Kv4.1 voltage-gated potassium channels. All variant-associated amino acid substitutions affect either the cytoplasmic N- or C-terminus of the channel protein except for two occurring in transmembrane segments 1 and 4. Kv4.1 channels were functionally characterized in the absence and presence of auxiliary β subunits. Variant-specific alterations of biophysical channel properties were diverse and varied in magnitude. Genetic data analysis in combination with our functional assessment shows that Kv4.1 channel dysfunction is involved in the pathogenesis of an X-linked neurodevelopmental disorder frequently associated with a variable neuropsychiatric clinical phenotype.
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Affiliation(s)
- Tassja Kalm
- Institute for Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Claudia Schob
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Hanna Völler
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Thatjana Gardeitchik
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Chiara Klöckner
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Annick Klabunde-Cherwon
- Division of Pediatric Epileptology, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Markus Ries
- Division of Pediatric Epileptology, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Francesca Beccaria
- Epilepsy Center, Department of Child Neuropsychiatry, Territorial Social-Health Agency, 46100 Mantova, Italy
| | - Francesca Madia
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Marcello Scala
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16145 Genoa, Italy
| | - Federico Zara
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16145 Genoa, Italy
| | - Floris Hofstede
- Department of General Pediatrics, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Marleen E H Simon
- Department of Clinical Genetics, University Medical Center Utrecht, Utrecht 3584 EA, the Netherlands
| | - Richard H van Jaarsveld
- Department of Clinical Genetics, University Medical Center Utrecht, Utrecht 3584 EA, the Netherlands
| | - Renske Oegema
- Department of Clinical Genetics, University Medical Center Utrecht, Utrecht 3584 EA, the Netherlands
| | - Koen L I van Gassen
- Department of Clinical Genetics, University Medical Center Utrecht, Utrecht 3584 EA, the Netherlands
| | - Sjoerd J B Holwerda
- Department of Clinical Genetics, University Medical Center Utrecht, Utrecht 3584 EA, the Netherlands
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam 3000 CA, the Netherlands; ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC University Medical Center, Rotterdam 3000 CA, the Netherlands; Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam 3000 CA, the Netherlands
| | - Arjan Bouman
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam 3000 CA, the Netherlands
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam 3000 CA, the Netherlands
| | - Sara Álvarez
- Genomics and Medicine, NIMGenetics, 28108 Madrid, Spain
| | - Alberto Fernández-Jaén
- Pediatric Neurology Department, Quironsalud University Hospital Madrid, School of Medicine, European University of Madrid, 28224 Madrid, Spain
| | - Javier Porta
- Genomics, Genologica Medica, 29016 Málaga, Spain
| | - Andrea Accogli
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre, QC H4A 3J1 Montreal, Canada; Department of Human Genetics, McGill University, QC H4A 3J1 Montreal, Canada
| | | | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16145 Genoa, Italy; Pediatric Neurology and Neuromuscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Michele Iacomino
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Jong-Hee Chae
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 110-744, Republic of Korea; Department of Genomic Medicine, Rare Disease Center, Seoul National University Hospital, Seoul 03080, Republic of Korea
| | - SeSong Jang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul 110-744, Republic of Korea
| | - Soo Y Kim
- Department of Genomic Medicine, Rare Disease Center, Seoul National University Hospital, Seoul 03080, Republic of Korea
| | - David Chitayat
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto ON M5G 1E2 Toronto, Canada; Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for SickKids, University of Toronto, M5G 1X8 Toronto, Canada
| | - Saadet Mercimek-Andrews
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for SickKids, University of Toronto, M5G 1X8 Toronto, Canada; Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, AB T6G 2H7 Edmonton, Canada
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45122 Essen, Germany
| | - Antje Kampmeier
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45122 Essen, Germany
| | - Alma Kuechler
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45122 Essen, Germany
| | - Harald Surowy
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45122 Essen, Germany
| | | | | | - Cecilia Mancini
- Molecular Genetics and Functional Genomics, Bambino Gesù Children's Hospital, IRCCS, 00146 Rome, Italy
| | - Simone Pizzi
- Molecular Genetics and Functional Genomics, Bambino Gesù Children's Hospital, IRCCS, 00146 Rome, Italy
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Bambino Gesù Children's Hospital, IRCCS, 00146 Rome, Italy
| | - Lucas Gauthier
- Department of Molecular Genetics and Cytogenomics, Rare and Autoinflammatory Diseases Unit, University Hospital of Montpellier, 34295 Montpellier, France
| | - David Genevieve
- Montpellier University, Inserm U1183, Montpellier, France; Department of Clinical Genetics, University Hospital of Montpellier, 34295 Montpellier, France
| | - Mylène Tharreau
- Department of Molecular Genetics and Cytogenomics, Rare and Autoinflammatory Diseases Unit, University Hospital of Montpellier, 34295 Montpellier, France
| | - Noy Azoulay
- The Genetic Institute of Maccabi Health Services, Rehovot 7610000, Israel; Raphael Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva 49100, Israel
| | - Gal Zaks-Hoffer
- Raphael Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva 49100, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nesia K Gilad
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Petah Tikvah 4920235, Israel
| | - Naama Orenstein
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Petah Tikvah 4920235, Israel
| | - Geneviève Bernard
- Division of Medical Genetics, Department of Specialized Medicine, Montreal Children's Hospital, McGill University Health Centre, QC H4A 3J1 Montreal, Canada; Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Isabelle Thiffault
- Genomic Medicine Center, Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO, USA; UKMC School of Medicine, University of Missouri Kansas City, Kansas City, MO, USA; Department of Pathology and Laboratory Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Jonas Denecke
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Theresia Herget
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Robert Bähring
- Institute for Cellular and Integrative Physiology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Stefan Kindler
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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4
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Nakajo K, Kasuya G. Modulation of potassium channels by transmembrane auxiliary subunits via voltage-sensing domains. Physiol Rep 2024; 12:e15980. [PMID: 38503563 PMCID: PMC10950684 DOI: 10.14814/phy2.15980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/07/2024] [Accepted: 03/07/2024] [Indexed: 03/21/2024] Open
Abstract
Voltage-gated K+ (KV ) and Ca2+ -activated K+ (KCa ) channels are essential proteins for membrane repolarization in excitable cells. They also play important physiological roles in non-excitable cells. Their diverse physiological functions are in part the result of their auxiliary subunits. Auxiliary subunits can alter the expression level, voltage dependence, activation/deactivation kinetics, and inactivation properties of the bound channel. KV and KCa channels are activated by membrane depolarization through the voltage-sensing domain (VSD), so modulation of KV and KCa channels through the VSD is reasonable. Recent cryo-EM structures of the KV or KCa channel complex with auxiliary subunits are shedding light on how these subunits bind to and modulate the VSD. In this review, we will discuss four examples of auxiliary subunits that bind directly to the VSD of KV or KCa channels: KCNQ1-KCNE3, Kv4-DPP6, Slo1-β4, and Slo1-γ1. Interestingly, their binding sites are all different. We also present some examples of how functionally critical binding sites can be determined by introducing mutations. These structure-guided approaches would be effective in understanding how VSD-bound auxiliary subunits modulate ion channels.
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Affiliation(s)
- Koichi Nakajo
- Division of Integrative Physiology, Department of PhysiologyJichi Medical UniversityShimotsukeJapan
| | - Go Kasuya
- Division of Integrative Physiology, Department of PhysiologyJichi Medical UniversityShimotsukeJapan
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5
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Polyák A, Topal L, Zombori-Tóth N, Tóth N, Prorok J, Kohajda Z, Déri S, Demeter-Haludka V, Hegyi P, Venglovecz V, Ágoston G, Husti Z, Gazdag P, Szlovák J, Árpádffy-Lovas T, Naveed M, Sarusi A, Jost N, Virág L, Nagy N, Baczkó I, Farkas AS, Varró A. Cardiac electrophysiological remodeling associated with enhanced arrhythmia susceptibility in a canine model of elite exercise. eLife 2023; 12:80710. [PMID: 36815557 PMCID: PMC10014074 DOI: 10.7554/elife.80710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 02/16/2023] [Indexed: 02/24/2023] Open
Abstract
The health benefits of regular physical exercise are well known. Even so, there is increasing evidence that the exercise regimes of elite athletes can evoke cardiac arrhythmias including ventricular fibrillation and even sudden cardiac death (SCD). The mechanism of exercise-induced arrhythmia and SCD is poorly understood. Here, we show that chronic training in a canine model (12 sedentary and 12 trained dogs) that mimics the regime of elite athletes induces electrophysiological remodeling (measured by ECG, patch-clamp, and immunocytochemical techniques) resulting in increases of both the trigger and the substrate for ventricular arrhythmias. Thus, 4 months sustained training lengthened ventricular repolarization (QTc: 237.1±3.4 ms vs. 213.6±2.8 ms, n=12; APD90: 472.8±29.6 ms vs. 370.1±32.7 ms, n=29 vs. 25), decreased transient outward potassium current (6.4±0.5 pA/pF vs. 8.8±0.9 pA/pF at 50 mV, n=54 vs. 42), and increased the short-term variability of repolarization (29.5±3.8 ms vs. 17.5±4.0 ms, n=27 vs. 18). Left ventricular fibrosis and HCN4 protein expression were also enhanced. These changes were associated with enhanced ectopic activity (number of escape beats from 0/hr to 29.7±20.3/hr) in vivo and arrhythmia susceptibility (elicited ventricular fibrillation: 3 of 10 sedentary dogs vs. 6 of 10 trained dogs). Our findings provide in vivo, cellular electrophysiological and molecular biological evidence for the enhanced susceptibility to ventricular arrhythmia in an experimental large animal model of endurance training.
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Affiliation(s)
- Alexandra Polyák
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Leila Topal
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Noémi Zombori-Tóth
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Noémi Tóth
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - János Prorok
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research NetworkSzegedHungary
| | - Zsófia Kohajda
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research NetworkSzegedHungary
| | - Szilvia Déri
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | | | - Péter Hegyi
- Centre for Translational Medicine and Institute of Pancreatic Diseases, Semmelweis UniversityBudapestHungary
- Institute for Translational Medicine, Medical School, University of PécsPécsHungary
- Translational Pancreatology Research Group, Interdisciplinary Centre of Excellence for Research Development and Innovation, University of SzegedSzegedHungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Gergely Ágoston
- Institute of Family Medicine, University of SzegedSzegedHungary
| | - Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Péter Gazdag
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Jozefina Szlovák
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Muhammad Naveed
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Annamária Sarusi
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research NetworkSzegedHungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of SzegedSzegedHungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of SzegedSzegedHungary
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research NetworkSzegedHungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of SzegedSzegedHungary
| | - Attila S Farkas
- Department of Internal Medicine, Cardiology ward, University of SzegedSzegedHungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of SzegedSzegedHungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research NetworkSzegedHungary
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of SzegedSzegedHungary
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6
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Malloy C, Ahern M, Lin L, Hoffman DA. Neuronal Roles of the Multifunctional Protein Dipeptidyl Peptidase-like 6 (DPP6). Int J Mol Sci 2022; 23:ijms23169184. [PMID: 36012450 PMCID: PMC9409431 DOI: 10.3390/ijms23169184] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/16/2022] Open
Abstract
The concerted action of voltage-gated ion channels in the brain is fundamental in controlling neuronal physiology and circuit function. Ion channels often associate in multi-protein complexes together with auxiliary subunits, which can strongly influence channel expression and function and, therefore, neuronal computation. One such auxiliary subunit that displays prominent expression in multiple brain regions is the Dipeptidyl aminopeptidase-like protein 6 (DPP6). This protein associates with A-type K+ channels to control their cellular distribution and gating properties. Intriguingly, DPP6 has been found to be multifunctional with an additional, independent role in synapse formation and maintenance. Here, we feature the role of DPP6 in regulating neuronal function in the context of its modulation of A-type K+ channels as well as its independent involvement in synaptic development. The prevalence of DPP6 in these processes underscores its importance in brain function, and recent work has identified that its dysfunction is associated with host of neurological disorders. We provide a brief overview of these and discuss research directions currently underway to advance our understanding of the contribution of DPP6 to their etiology.
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7
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Modulation of KV4.3-KChIP2 Channels by IQM-266: Role of DPP6 and KCNE2. Int J Mol Sci 2022; 23:ijms23169170. [PMID: 36012438 PMCID: PMC9409462 DOI: 10.3390/ijms23169170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 11/17/2022] Open
Abstract
The transient outward potassium current (Itof) is generated by the activation of KV4 channels assembled with KChIP2 and other accessory subunits (DPP6 and KCNE2). To test the hypothesis that these subunits modify the channel pharmacology, we analyzed the electrophysiological effects of (3-(2-(3-phenoxyphenyl)acetamido)-2-naphthoic acid) (IQM-266), a new KChIP2 ligand, on the currents generated by KV4.3/KChIP2, KV4.3/KChIP2/DPP6 and KV4.3/KChIP2/KCNE2 channels. CHO cells were transiently transfected with cDNAs codifying for different proteins (KV4.3/KChIP2, KV4.3/KChIP2/DPP6 or KV4.3/KChIP2/KCNE2), and the potassium currents were recorded using the whole-cell patch-clamp technique. IQM-266 decreased the maximum peak of KV4.3/KChIP2, KV4.3/KChIP2/DPP6 and KV4.3/KChIP2/KCNE2 currents, slowing their time course of inactivation in a concentration-, voltage-, time- and use-dependent manner. IQM-266 produced an increase in the charge in KV4.3/KChIP2 channels that was intensified when DPP6 was present and abolished in the presence of KCNE2. IQM-266 induced an activation unblocking effect during the application of trains of pulses to cells expressing KV4.3/KChIP2 and KV4.3/KChIP2/KCNE2, but not in KV4.3/KChIP2/DPP6 channels. Overall, all these results are consistent with a preferential IQM-266 binding to an active closed state of Kv4.3/KChIP2 and Kv4.3/KChIP2/KCNE2 channels, whereas in the presence of DPP6, IQM-266 binds preferentially to an inactivated state. In conclusion, DPP6 and KCNE2 modify the pharmacological response of KV4.3/KChIP2 channels to IQM-266.
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8
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Wang M, Tu X. The Genetics and Epigenetics of Ventricular Arrhythmias in Patients Without Structural Heart Disease. Front Cardiovasc Med 2022; 9:891399. [PMID: 35783865 PMCID: PMC9240357 DOI: 10.3389/fcvm.2022.891399] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/25/2022] [Indexed: 12/19/2022] Open
Abstract
Ventricular arrhythmia without structural heart disease is an arrhythmic disorder that occurs in structurally normal heart and no transient or reversible arrhythmia factors, such as electrolyte disorders and myocardial ischemia. Ventricular arrhythmias without structural heart disease can be induced by multiple factors, including genetics and environment, which involve different genetic and epigenetic regulation. Familial genetic analysis reveals that cardiac ion-channel disorder and dysfunctional calcium handling are two major causes of this type of heart disease. Genome-wide association studies have identified some genetic susceptibility loci associated with ventricular tachycardia and ventricular fibrillation, yet relatively few loci associated with no structural heart disease. The effects of epigenetics on the ventricular arrhythmias susceptibility genes, involving non-coding RNAs, DNA methylation and other regulatory mechanisms, are gradually being revealed. This article aims to review the knowledge of ventricular arrhythmia without structural heart disease in genetics, and summarizes the current state of epigenetic regulation.
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9
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Salisbury S, McCracken GR, Perry R, Keefe D, Layton KKS, Kess T, Nugent CM, Leong JS, Bradbury IR, Koop BF, Ferguson MM, Ruzzante DE. The Genomic Consistency of the Loss of Anadromy in an Arctic Fish (Salvelinus alpinus). Am Nat 2022; 199:617-635. [DOI: 10.1086/719122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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Tsermpini EE, Redenšek S, Dolžan V. Genetic Factors Associated With Tardive Dyskinesia: From Pre-clinical Models to Clinical Studies. Front Pharmacol 2022; 12:834129. [PMID: 35140610 PMCID: PMC8819690 DOI: 10.3389/fphar.2021.834129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 12/31/2021] [Indexed: 01/14/2023] Open
Abstract
Tardive dyskinesia is a severe motor adverse event of antipsychotic medication, characterized by involuntary athetoid movements of the trunk, limbs, and/or orofacial areas. It affects two to ten patients under long-term administration of antipsychotics that do not subside for years even after the drug is stopped. Dopamine, serotonin, cannabinoid receptors, oxidative stress, plasticity factors, signaling cascades, as well as CYP isoenzymes and transporters have been associated with tardive dyskinesia (TD) occurrence in terms of genetic variability and metabolic capacity. Besides the factors related to the drug and the dose and patients’ clinical characteristics, a very crucial variable of TD development is individual susceptibility and genetic predisposition. This review summarizes the studies in experimental animal models and clinical studies focusing on the impact of genetic variations on TD occurrence. We identified eight genes emerging from preclinical findings that also reached statistical significance in at least one clinical study. The results of clinical studies are often conflicting and non-conclusive enough to support implementation in clinical practice.
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11
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Bano-Otalora B, Moye MJ, Brown T, Lucas RJ, Diekman CO, Belle MD. Daily electrical activity in the master circadian clock of a diurnal mammal. eLife 2021; 10:68179. [PMID: 34845984 PMCID: PMC8631794 DOI: 10.7554/elife.68179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 10/09/2021] [Indexed: 11/13/2022] Open
Abstract
Circadian rhythms in mammals are orchestrated by a central clock within the suprachiasmatic nuclei (SCN). Our understanding of the electrophysiological basis of SCN activity comes overwhelmingly from a small number of nocturnal rodent species, and the extent to which these are retained in day-active animals remains unclear. Here, we recorded the spontaneous and evoked electrical activity of single SCN neurons in the diurnal rodent Rhabdomys pumilio, and developed cutting-edge data assimilation and mathematical modeling approaches to uncover the underlying ionic mechanisms. As in nocturnal rodents, R. pumilio SCN neurons were more excited during daytime hours. By contrast, the evoked activity of R. pumilio neurons included a prominent suppressive response that is not present in the SCN of nocturnal rodents. Our modeling revealed and subsequent experiments confirmed transient subthreshold A-type potassium channels as the primary determinant of this response, and suggest a key role for this ionic mechanism in optimizing SCN function to accommodate R. pumilio's diurnal niche.
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Affiliation(s)
- Beatriz Bano-Otalora
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Matthew J Moye
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, United States.,Department of Quantitative Pharmacology and Pharmacometrics (QP2), Kenilworth, United States
| | - Timothy Brown
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Robert J Lucas
- Centre for Biological Timing, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, United States.,EPSRC Centre for Predictive Modelling in Healthcare, Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Mino Dc Belle
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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12
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Welch MA, Jansen LAR, Baro DJ. SUMOylation of the Kv4.2 Ternary Complex Increases Surface Expression and Current Amplitude by Reducing Internalization in HEK 293 Cells. Front Mol Neurosci 2021; 14:757278. [PMID: 34795560 PMCID: PMC8593141 DOI: 10.3389/fnmol.2021.757278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
Kv4 α-subunits exist as ternary complexes (TC) with potassium channel interacting proteins (KChIP) and dipeptidyl peptidase-like proteins (DPLP); multiple ancillary proteins also interact with the α-subunits throughout the channel’s lifetime. Dynamic regulation of Kv4.2 protein interactions adapts the transient potassium current, IA, mediated by Kv4 α-subunits. Small ubiquitin-like modifier (SUMO) is an 11 kD peptide post-translationally added to lysine (K) residues to regulate protein–protein interactions. We previously demonstrated that when expressed in human embryonic kidney (HEK) cells, Kv4.2 can be SUMOylated at two K residues, K437 and K579. SUMOylation at K437 increased surface expression of electrically silent channels while SUMOylation at K579 reduced IA maximal conductance (Gmax) without altering surface expression. KChIP and DPLP subunits are known to modify the pattern of Kv4.2 post-translational decorations and/or their effects. In this study, co-expressing Kv4.2 with KChIP2a and DPP10c altered the effects of enhanced Kv4.2 SUMOylation. First, the effect of enhanced SUMOylation was the same for a TC containing either the wild-type Kv4.2 or the mutant K437R Kv4.2, suggesting that either the experimental manipulation no longer enhanced K437 SUMOylation or K437 SUMOylation no longer influenced Kv4.2 surface expression. Second, instead of decreasing IA Gmax, enhanced SUMOylation at K579 now produced a significant ∼37–70% increase in IA maximum conductance (Gmax) and a significant ∼30–50% increase in Kv4.2g surface expression that was accompanied by a 65% reduction in TC internalization. Blocking clathrin-mediated endocytosis (CME) in HEK cells expressing the Kv4.2 TC mimicked and occluded the effect of SUMO on IA Gmax; however, the amount of Kv4.2 associated with the major adaptor for constitutive CME, adaptor protein 2 (AP2), was not SUMO dependent. Thus, SUMOylation reduced Kv4.2 internalization by acting downstream of Kv4.2 recruitment into clathrin-coated pits. In sum, the two major findings of this study are: SUMOylation of Kv4.2 at K579 regulates TC internalization most likely by promoting channel recycling. Additionally, there is a reciprocity between Kv4.2 SUMOylation and the Kv4.2 interactome such that SUMOylation regulates the interactome and the interactome influences the pattern and effect of SUMOylation.
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Affiliation(s)
- Meghyn A Welch
- Department of Biology, Georgia State University, Atlanta, GA, United States
| | | | - Deborah J Baro
- Department of Biology, Georgia State University, Atlanta, GA, United States.,Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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13
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Structural basis of gating modulation of Kv4 channel complexes. Nature 2021; 599:158-164. [PMID: 34552243 PMCID: PMC8566240 DOI: 10.1038/s41586-021-03935-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 08/19/2021] [Indexed: 11/08/2022]
Abstract
Modulation of voltage-gated potassium (Kv) channels by auxiliary subunits is central to the physiological function of channels in the brain and heart1,2. Native Kv4 tetrameric channels form macromolecular ternary complexes with two auxiliary β-subunits—intracellular Kv channel-interacting proteins (KChIPs) and transmembrane dipeptidyl peptidase-related proteins (DPPs)—to evoke rapidly activating and inactivating A-type currents, which prevent the backpropagation of action potentials1–5. However, the modulatory mechanisms of Kv4 channel complexes remain largely unknown. Here we report cryo-electron microscopy structures of the Kv4.2–DPP6S–KChIP1 dodecamer complex, the Kv4.2–KChIP1 and Kv4.2–DPP6S octamer complexes, and Kv4.2 alone. The structure of the Kv4.2–KChIP1 complex reveals that the intracellular N terminus of Kv4.2 interacts with its C terminus that extends from the S6 gating helix of the neighbouring Kv4.2 subunit. KChIP1 captures both the N and the C terminus of Kv4.2. In consequence, KChIP1 would prevent N-type inactivation and stabilize the S6 conformation to modulate gating of the S6 helices within the tetramer. By contrast, unlike the reported auxiliary subunits of voltage-gated channel complexes, DPP6S interacts with the S1 and S2 helices of the Kv4.2 voltage-sensing domain, which suggests that DPP6S stabilizes the conformation of the S1–S2 helices. DPP6S may therefore accelerate the voltage-dependent movement of the S4 helices. KChIP1 and DPP6S do not directly interact with each other in the Kv4.2–KChIP1–DPP6S ternary complex. Thus, our data suggest that two distinct modes of modulation contribute in an additive manner to evoke A-type currents from the native Kv4 macromolecular complex. Cryo-electron microscopy structures of the voltage-gated potassium channel Kv4.2 alone and in complex with auxiliary subunits (DPP6S and/or KChIP1) reveal the distinct mechanisms of these two different subunits in modulating channel activity.
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14
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Zhang Y, Tachtsidis G, Schob C, Koko M, Hedrich UBS, Lerche H, Lemke JR, Haeringen A, Ruivenkamp C, Prescott T, Tveten K, Gerstner T, Pruniski B, DiTroia S, VanNoy GE, Rehm HL, McLaughlin H, Bolz HJ, Zechner U, Bryant E, McDonough T, Kindler S, Bähring R. KCND2 variants associated with global developmental delay differentially impair Kv4.2 channel gating. Hum Mol Genet 2021; 30:2300-2314. [PMID: 34245260 DOI: 10.1093/hmg/ddab192] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 11/13/2022] Open
Abstract
Here, we report on six unrelated individuals, all presenting with early-onset global developmental delay, associated with impaired motor, speech and cognitive development, partly with developmental epileptic encephalopathy and physical dysmorphisms. All individuals carry heterozygous missense variants of KCND2, which encodes the voltage-gated potassium (Kv) channel α-subunit Kv4.2. The amino acid substitutions associated with the variants, p.(Glu323Lys) (E323K), p.(Pro403Ala) (P403A), p.(Val404Leu) (V404L) and p.(Val404Met) (V404M), affect sites known to be critical for channel gating. To unravel their likely pathogenicity, recombinant mutant channels were studied in the absence and presence of auxiliary β-subunits under two-electrode voltage-clamp in Xenopus oocytes. All channel mutants exhibited slowed and incomplete macroscopic inactivation, and the P403A variant in addition slowed activation. Co-expression of KChIP2 or DPP6 augmented the functional expression of both wild-type and mutant channels, however, the auxiliary β-subunit-mediated gating modifications differed from wild-type and among mutants. To simulate the putative setting in the affected individuals, heteromeric Kv4.2 channels (wild-type + mutant) were studied as ternary complexes (containing both KChIP2 and DPP6). In the heteromeric ternary configuration, the E323K variant exhibited only marginal functional alterations compared to homomeric wild-type ternary, compatible with mild loss-of-function. By contrast, the P403A, V404L and V404M variants displayed strong gating impairment in the heteromeric ternary configuration, compatible with loss or gain-of-function. Our results support the etiological involvement of Kv4.2 channel gating impairment in early-onset monogenic global developmental delay. In addition, they suggest that gain-of-function mechanisms associated with a substitution of V404 increase epileptic seizure susceptibility.
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Affiliation(s)
- Yongqiang Zhang
- Institute for Cellular and Integrative Physiology, Center for Experimental Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany.,Southeast University, Nanjing, China
| | - Georgios Tachtsidis
- Institute for Cellular and Integrative Physiology, Center for Experimental Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Claudia Schob
- Institute for Human Genetics, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, Tübingen, Germany
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, Tübingen, Germany
| | - Johannes R Lemke
- University Center for Rare Diseases, Institute for Human Genetics, University Hospital, Leipzig, Germany
| | - Arie Haeringen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Trine Prescott
- Department of Medical Genetics, Telemark Hospital Trust, Skien, Norway
| | - Kristian Tveten
- Department of Medical Genetics, Telemark Hospital Trust, Skien, Norway
| | - Thorsten Gerstner
- Department of Child Neurology and Rehabilitation and Department of Pediatrics, Hospital of Southern Norway, Arendal, Norway
| | - Brianna Pruniski
- Division of Genetics & Metabolism, Phoenix Children's Medical Group, Phoenix, AZ, USA
| | - Stephanie DiTroia
- Center for Mendelian Genomics and Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Grace E VanNoy
- Center for Mendelian Genomics and Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Heidi L Rehm
- Center for Mendelian Genomics and Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Hanno J Bolz
- Senckenberg Centre for Human Genetics, Frankfurt/Main, Germany.,Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Ulrich Zechner
- Senckenberg Centre for Human Genetics, Frankfurt/Main, Germany.,Institute of Human Genetics, University Medical Center Mainz, Mainz, Germany
| | - Emily Bryant
- Ann & Robert H Lurie Children's Hospital of Chicago, Department of Pediatrics, Northwestern University Feinberg Scool of Medicine, Chicago, IL, USA
| | - Tiffani McDonough
- Ann & Robert H Lurie Children's Hospital of Chicago, Department of Pediatrics, Northwestern University Feinberg Scool of Medicine, Chicago, IL, USA
| | - Stefan Kindler
- Institute for Human Genetics, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Robert Bähring
- Institute for Cellular and Integrative Physiology, Center for Experimental Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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15
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Cheng P, Qiu Z, Du Y. Potassium channels and autism spectrum disorder: An overview. Int J Dev Neurosci 2021; 81:479-491. [PMID: 34008235 DOI: 10.1002/jdn.10123] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 11/07/2022] Open
Abstract
Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders characterized by impaired social interaction and communication, and restricted, repetitive patterns of behaviors, interests, or activities. It had been demonstrated that potassium channels played a key role in regulating neuronal excitability, which was closely associated with neurological diseases including epilepsy, ataxia, myoclonus, and psychiatric disorders. In recent years, a growing body of evidence from whole-genome sequencing and whole-exome sequencing had identified several ASD susceptibility genes of potassium channels in ASD subjects. Genetically dysfunction of potassium channels may be involved in altered neuronal excitability and abnormal brain function in the pathogenesis of ASD. This review summarizes current findings on the features of ASD-risk genes (KCND2, KCNQ2, KCNQ3, KCNH5, KCNJ2, KCNJ10, and KCNMA1) and further expatiate their potential role in the pathogenicity of ASD.
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Affiliation(s)
- Peipei Cheng
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zilong Qiu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Yasong Du
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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16
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Light-regulated voltage-gated potassium channels for acute interrogation of channel function in neurons and behavior. PLoS One 2021; 16:e0248688. [PMID: 33755670 PMCID: PMC7987177 DOI: 10.1371/journal.pone.0248688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 03/03/2021] [Indexed: 01/02/2023] Open
Abstract
Voltage-gated potassium (Kv) channels regulate the membrane potential and conductance of excitable cells to control the firing rate and waveform of action potentials. Even though Kv channels have been intensely studied for over 70 year, surprisingly little is known about how specific channels expressed in various neurons and their functional properties impact neuronal network activity and behavior in vivo. Although many in vivo genetic manipulations of ion channels have been tried, interpretation of these results is complicated by powerful homeostatic plasticity mechanisms that act to maintain function following perturbations in excitability. To better understand how Kv channels shape network function and behavior, we have developed a novel optogenetic technology to acutely regulate Kv channel expression with light by fusing the light-sensitive LOV domain of Vaucheria frigida Aureochrome 1 to the N-terminus of the Kv1 subunit protein to make an Opto-Kv1 channel. Recording of Opto-Kv1 channels expressed in Xenopus oocytes, mammalian cells, and neurons show that blue light strongly induces the current expression of Opto-Kv1 channels in all systems tested. We also find that an Opto-Kv1 construct containing a dominant-negative pore mutation (Opto-Kv1(V400D)) can be used to down-regulate Kv1 currents in a blue light-dependent manner. Finally, to determine whether Opto-Kv1 channels can elicit light-dependent behavioral effect in vivo, we targeted Opto-Kv1 (V400D) expression to Kv1.3-expressing mitral cells of the olfactory bulb in mice. Exposure of the bulb to blue light for 2–3 hours produced a significant increase in sensitivity to novel odors after initial habituation to a similar odor, comparable to behavioral changes seen in Kv1.3 knockout animals. In summary, we have developed novel photoactivatable Kv channels that provide new ways to interrogate neural circuits in vivo and to examine the roles of normal and disease-causing mutant Kv channels in brain function and behavior.
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17
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Seifert C, Storch S, Bähring R. Modulation of Kv4.2/KChIP3 interaction by the ceroid lipofuscinosis neuronal 3 protein CLN3. J Biol Chem 2020; 295:12099-12110. [PMID: 32641494 PMCID: PMC7443505 DOI: 10.1074/jbc.ra120.013828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/22/2020] [Indexed: 11/06/2022] Open
Abstract
Voltage-gated potassium (Kv) channels of the Kv4 subfamily associate with Kv channel-interacting proteins (KChIPs), which leads to enhanced surface expression and shapes the inactivation gating of these channels. KChIP3 has been reported to also interact with the late endosomal/lysosomal membrane glycoprotein CLN3 (ceroid lipofuscinosis neuronal 3), which is modified because of gene mutation in juvenile neuronal ceroid lipofuscinosis (JNCL). The present study was undertaken to find out whether and how CLN3, by its interaction with KChIP3, may indirectly modulate Kv4.2 channel expression and function. To this end, we expressed KChIP3 and CLN3, either individually or simultaneously, together with Kv4.2 in HEK 293 cells. We performed co-immunoprecipitation experiments and found a lower amount of KChIP3 bound to Kv4.2 in the presence of CLN3. In whole-cell patch-clamp experiments, we examined the effects of CLN3 co-expression on the KChIP3-mediated modulation of Kv4.2 channels. Simultaneous co-expression of CLN3 and KChIP3 with Kv4.2 resulted in a suppression of the typical KChIP3-mediated modulation; i.e. we observed less increase in current density, less slowing of macroscopic current decay, less acceleration of recovery from inactivation, and a less positively shifted voltage dependence of steady-state inactivation. The suppression of the KChIP3-mediated modulation of Kv4.2 channels was weaker for the JNCL-related missense mutant CLN3R334C and for a JNCL-related C-terminal deletion mutant (CLN3ΔC). Our data support the notion that CLN3 is involved in Kv4.2/KChIP3 somatodendritic A-type channel formation, trafficking, and function, a feature that may be lost in JNCL.
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Affiliation(s)
- Carolin Seifert
- Institut für Zelluläre und Integrative Physiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Stephan Storch
- Klinik und Poliklinik für Kinder- und Jugendmedizin, Pädiatrische Forschung, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Robert Bähring
- Institut für Zelluläre und Integrative Physiologie, Zentrum für Experimentelle Medizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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18
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A new world of heme function. Pflugers Arch 2020; 472:547-548. [PMID: 32388730 DOI: 10.1007/s00424-020-02388-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 10/24/2022]
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19
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Allen NM, Weckhuysen S, Gorman K, King MD, Lerche H. Genetic potassium channel-associated epilepsies: Clinical review of the K v family. Eur J Paediatr Neurol 2020; 24:105-116. [PMID: 31932120 DOI: 10.1016/j.ejpn.2019.12.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 12/22/2022]
Abstract
Next-generation sequencing has enhanced discovery of many disease-associated genes in previously unexplained epilepsies, mainly in developmental and epileptic encephalopathies and familial epilepsies. We now classify these disorders according to the underlying molecular pathways, which encompass a diverse array of cellular and sub-cellular compartments/signalling processes including voltage-gated ion-channel defects. With the aim to develop and increase the use of precision medicine therapies, understanding the pathogenic mechanisms and consequences of disease-causing variants has gained major relevance in clinical care. The super-family of voltage-gated potassium channels is the largest and most diverse family among the ion channels, encompassing approximately 80 genes. Key potassium channelopathies include those affecting the KV, KCa and Kir families, a significant proportion of which have been implicated in neurological disease. As for other ion channel disorders, different pathogenic variants within any individual voltage-gated potassium channel gene tend to affect channel protein function differently, causing heterogeneous clinical phenotypes. The focus of this review is to summarise recent clinical developments regarding the key voltage-gated potassium (KV) family-related epilepsies, which now encompasses approximately 12 established disease-associated genes, from the KCNA-, KCNB-, KCNC-, KCND-, KCNV-, KCNQ- and KCNH-subfamilies.
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Affiliation(s)
- Nicholas M Allen
- Department of Paediatrics, National University of Ireland, Galway, Ireland; Department of Paediatrics (Neurology), Galway University Hospital, Ireland; Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Ireland.
| | - Sarah Weckhuysen
- Neurogenetics Group, Center for Molecular Neurology, VIB-University of Antwerp, Antwerp, Belgium; Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Kathleen Gorman
- Department of Paediatric Neurology & Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin 1, Ireland; University College Dublin School of Medicine and Medical Science, University College, Dublin, Ireland
| | - Mary D King
- Department of Paediatric Neurology & Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin 1, Ireland; University College Dublin School of Medicine and Medical Science, University College, Dublin, Ireland
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tubingen, Germany
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20
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Belau F, Metzner K, Christ T, Ravens U, Schaefer M, Künzel S, Li W, Wettwer E, Dobrev D, El-Armouche A, Kämmerer S. DPP10 is a new regulator of Nav1.5 channels in human heart. Int J Cardiol 2019; 284:68-73. [DOI: 10.1016/j.ijcard.2018.12.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 12/14/2018] [Accepted: 12/27/2018] [Indexed: 10/27/2022]
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21
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Welch MA, Forster LA, Atlas SI, Baro DJ. SUMOylating Two Distinct Sites on the A-type Potassium Channel, Kv4.2, Increases Surface Expression and Decreases Current Amplitude. Front Mol Neurosci 2019; 12:144. [PMID: 31213982 PMCID: PMC6554448 DOI: 10.3389/fnmol.2019.00144] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 05/17/2019] [Indexed: 12/15/2022] Open
Abstract
Post-translational conjugation of Small Ubiquitin-like Modifier (SUMO) peptides to lysine (K) residues on target proteins alters their interactions. SUMOylation of a target protein can either promote its interaction with other proteins that possess SUMO binding domains, or it can prevent target protein interactions that normally occur in the absence of SUMOylation. One subclass of voltage-gated potassium channels that mediates an A-type current, IA, exists as a ternary complex comprising Kv4 pore-forming subunits, Kv channel interacting proteins (KChIP) and transmembrane dipeptidyl peptidase like proteins (DPPL). SUMOylation could potentially regulate intra- and/or intermolecular interactions within the complex. This study began to test this hypothesis and showed that Kv4.2 channels were SUMOylated in the rat brain and in human embryonic kidney (HEK) cells expressing a GFP-tagged mouse Kv4.2 channel (Kv4.2g). Prediction software identified two putative SUMOylation sites in the Kv4.2 C-terminus at K437 and K579. These sites were conserved across mouse, rat, and human Kv4.2 channels and across mouse Kv4 isoforms. Increasing Kv4.2g SUMOylation at each site by ~30% produced a significant ~22%–50% decrease in IA Gmax, and a ~70%–95% increase in channel surface expression. Site-directed mutagenesis of Kv4.2g showed that K437 SUMOylation regulated channel surface expression, while K579 SUMOylation controlled IA Gmax. The K579R mutation mimicked and occluded the SUMOylation-mediated decrease in IA Gmax, suggesting that SUMOylation at K579 blocked an intra- or inter-protein interaction involving K579. The K437R mutation did not obviously alter channel surface expression or biophysical properties, but it did block the SUMOylation-mediated increase in channel surface expression. Interestingly, enhancing K437 SUMOylation in the K579R mutant roughly doubled channel surface expression, but produced no change in IA Gmax, suggesting that the newly inserted channels were electrically silent. This is the first report that Kv4.2 channels are SUMOylated and that SUMOylation can independently regulate Kv4.2 surface expression and IA Gmax in opposing directions. The next step will be to determine if/how SUMOylation affects Kv4 interactions within the ternary complex.
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Affiliation(s)
- Meghyn A Welch
- Department of Biology, Georgia State University, Atlanta, GA, United States
| | - Lori A Forster
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Selin I Atlas
- Department of Biology, Georgia State University, Atlanta, GA, United States
| | - Deborah J Baro
- Department of Biology, Georgia State University, Atlanta, GA, United States.,Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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22
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Reduced hybrid/complex N-glycosylation disrupts cardiac electrical signaling and calcium handling in a model of dilated cardiomyopathy. J Mol Cell Cardiol 2019; 132:13-23. [PMID: 31071333 DOI: 10.1016/j.yjmcc.2019.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/12/2019] [Accepted: 05/01/2019] [Indexed: 12/19/2022]
Abstract
Dilated cardiomyopathy (DCM) is the third most common cause of heart failure, with ~70% of DCM cases considered idiopathic. We showed recently, through genetic ablation of the MGAT1 gene, which encodes an essential glycosyltransferase (GlcNAcT1), that prevention of cardiomyocyte hybrid/complex N-glycosylation was sufficient to cause DCM that led to heart failure and early death. Our findings are consistent with increasing evidence suggesting a link between aberrant glycosylation and heart diseases of acquired and congenital etiologies. However, the mechanisms by which changes in glycosylation contribute to disease onset and progression remain largely unknown. Activity and gating of voltage-gated Na+ and K+ channels (Nav and Kv respectively) play pivotal roles in the initiation, shaping and conduction of cardiomyocyte action potentials (APs) and aberrant channel activity was shown to contribute to cardiac disease. We and others showed that glycosylation can impact Nav and Kv function; therefore, here, we investigated the effects of reduced cardiomyocyte hybrid/complex N-glycosylation on channel activity to investigate whether chronic aberrant channel function can contribute to DCM. Ventricular cardiomyocytes from MGAT1 deficient (MGAT1KO) mice display prolonged APs and pacing-induced aberrant early re-activation that can be attributed to, at least in part, a significant reduction in Kv expression and activity that worsens over time suggesting heart disease-related remodeling. MGAT1KO Nav demonstrate no change in expression or maximal conductance but show depolarizing shifts in voltage-dependent gating. Together, the changes in MGAT1KO Nav and Kv function likely contribute to observed anomalous electrocardiograms and Ca2+ handling. These findings provide insight into mechanisms by which altered glycosylation contributes to DCM through changes in Nav and Kv activity that impact conduction, Ca2+ handling and contraction. The MGAT1KO can also serve as a useful model to study the effects of aberrant electrical signaling on cardiac function and the remodeling events that can occur with heart disease progression.
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23
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Gonzalez S, Villa E, Rodriguez M, Ramirez M, Zavala J, Armas R, Dassori A, Contreras J, Raventós H, Flores D, Jerez A, Ontiveros A, Nicolini H, Escamilla M. Fine-mapping scan of bipolar disorder susceptibility loci in Latino pedigrees. Am J Med Genet B Neuropsychiatr Genet 2019; 180:213-222. [PMID: 30779416 DOI: 10.1002/ajmg.b.32715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/27/2018] [Accepted: 01/28/2019] [Indexed: 11/11/2022]
Abstract
We previously identified bipolar disorder (BD) susceptibility loci on 8q24, 14q32, and 2q12-14 in a genome-wide nonparametric linkage screen in a Latino cohort. We now perform a fine mapping analysis using a dense map of additional SNPs to identify BD susceptibility genes within these regions. One thousand nine hundred and thirty-eight individuals with Latino ancestry (880 individuals with BD Type I or Schizoaffective, Bipolar Type) from 416 Latino pedigrees from the United States, Mexico, Costa Rica, and Guatemala were genotyped with 3,074 SNPs to provide dense coverage of the 8q24 (11.5 cM), 14q32 (7.5 cM), and 2q12-14 (6.5 cM) chromosomal loci. Single-marker association tests in the presence of linkage were performed using the LAMP software. The top linkage peak (rs7834818; LOD = 5.08, p = 3.30E - 5) and associated single marker (rs2280915, p = 2.70E - 12) were located within FBXO32 on 8q24. On chromosome 2, the top linkage peak (rs6750326; LOD = 5.06, p = 3.50E - 5) and associated single marker (rs11887088, p = 2.90E - 6) were located in intragenic regions near ACTR3 and DPP10. None of the additional markers in the region around chromosome 14q32 met significance levels for linkage or association. We identified six SNPs on 2q12-q14 and one SNP in FBXO32 on 8q24 that were significantly associated with BD in this Latino cohort.
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Affiliation(s)
- Suzanne Gonzalez
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas.,Departments of Psychiatry and Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Erika Villa
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Marco Rodriguez
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Mercedes Ramirez
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas.,Department of Psychiatry, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Juan Zavala
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas.,Department of Psychiatry, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Regina Armas
- Langley Porter Psychiatric Institute, University of California at San Francisco, San Francisco, California
| | - Albana Dassori
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, Texas.,Department of Psychiatry, South Texas Veterans Health Care System, San Antonio, Texas
| | - Javier Contreras
- Centro de Investigación en Biología Celular y Molecular y Escuela de Biologia, Universidad de Costa Rica, San Jose, Costa Rica
| | - Henriette Raventós
- Centro de Investigación en Biología Celular y Molecular y Escuela de Biologia, Universidad de Costa Rica, San Jose, Costa Rica
| | - Deborah Flores
- Los Angeles Biomedical Research Center at Harbor, University of California Los Angeles Medical Center, Torrance, California
| | - Alvaro Jerez
- Centro Internacional de Trastornos Afectivos y de la Conducta Adictiva, Guatemala City, Guatemala
| | - Alfonso Ontiveros
- Departamento de Psiquiatria, Hospital Universitario UANL, Monterrey, Nuevo Leon, Mexico
| | - Humberto Nicolini
- Grupo de Estudios Médicos y Familiares Carracci S.C., México, Distrito Federal, Mexico.,Laboratorio de Enfermedades Psychiatricas y Neurodegenerativas, Instituto Nacional de Medicina Genómica, México, Distrito Federal, Mexico
| | - Michael Escamilla
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas.,Department of Psychiatry, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
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24
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Ni H, Rajamani S, Giles WR. Novel regulation of the mammalian cardiac Na + channel by dipeptidyl peptidase 10 interactions: An editorial comment. Int J Cardiol 2019; 284:74-76. [PMID: 30827732 DOI: 10.1016/j.ijcard.2019.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/07/2019] [Indexed: 11/29/2022]
Affiliation(s)
- H Ni
- Department of Pharmacology, University of California, Davis, CA, United States of America
| | - S Rajamani
- Cardiometabolic Disorders, Amgen Research, South San Francisco, CA, United States of America
| | - W R Giles
- Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada.
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25
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Kv4.2 autism and epilepsy mutation enhances inactivation of closed channels but impairs access to inactivated state after opening. Proc Natl Acad Sci U S A 2018; 115:E3559-E3568. [PMID: 29581270 DOI: 10.1073/pnas.1717082115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A de novo mutation in the KCND2 gene, which encodes the Kv4.2 K+ channel, was identified in twin boys with intractable, infant-onset epilepsy and autism. Kv4.2 channels undergo closed-state inactivation (CSI), a mechanism by which channels inactivate without opening during subthreshold depolarizations. CSI dynamically modulates neuronal excitability and action potential back propagation in response to excitatory synaptic input, controlling Ca2+ influx into dendrites and regulating spike timing-dependent plasticity. Here, we show that the V404M mutation specifically affects the mechanism of CSI, enhancing the inactivation of channels that have not opened while dramatically impairing the inactivation of channels that have opened. The mutation gives rise to these opposing effects by increasing the stability of the inactivated state and in parallel, profoundly slowing the closure of open channels, which according to our data, is required for CSI. The larger volume of methionine compared with valine is a major factor underlying altered inactivation gating. Our results suggest that V404M increases the strength of the physical interaction between the pore gate and the voltage sensor regardless of whether the gate is open or closed. Furthermore, in contrast to previous proposals, our data strongly suggest that physical coupling between the voltage sensor and the pore gate is maintained in the inactivated state. The state-dependent effects of V404M on CSI are expected to disturb the regulation of neuronal excitability and the induction of spike timing-dependent plasticity. Our results strongly support a role for altered CSI gating in the etiology of epilepsy and autism in the affected twins.
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26
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Zhang Y, Poobalasingam T, Yates LL, Walker SA, Taylor MS, Chessum L, Harrison J, Tsaprouni L, Adcock IM, Lloyd CM, Cookson WO, Moffatt MF, Dean CH. Manipulation of dipeptidylpeptidase 10 in mouse and human in vivo and in vitro models indicates a protective role in asthma. Dis Model Mech 2018; 11:dmm.031369. [PMID: 29361513 PMCID: PMC5818078 DOI: 10.1242/dmm.031369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 12/07/2017] [Indexed: 12/20/2022] Open
Abstract
We previously identified dipeptidylpeptidase 10 (DPP10) on chromosome 2 as a human asthma susceptibility gene, through positional cloning. Initial association results were confirmed in many subsequent association studies but the functional role of DPP10 in asthma remains unclear. Using the MRC Harwell N-ethyl-N-nitrosourea (ENU) DNA archive, we identified a point mutation in Dpp10 that caused an amino acid change from valine to aspartic acid in the β-propeller region of the protein. Mice carrying this point mutation were recovered and a congenic line was established (Dpp10145D). Macroscopic examination and lung histology revealed no significant differences between wild-type and Dpp10145D/145D mice. However, after house dust mite (HDM) treatment, Dpp10 mutant mice showed significantly increased airway resistance in response to 100 mg/ml methacholine. Total serum IgE levels and bronchoalveolar lavage (BAL) eosinophil counts were significantly higher in homozygotes than in control mice after HDM treatment. DPP10 protein is present in airway epithelial cells and altered expression is observed in both tissue from asthmatic patients and in mice following HDM challenge. Moreover, knockdown of DPP10 in human airway epithelial cells results in altered cytokine responses. These results show that a Dpp10 point mutation leads to increased airway responsiveness following allergen challenge and provide biological evidence to support previous findings from human genetic studies.
This article has an associated First Person interview with the first author of the paper. Summary: Here, we show a novel mouse model carrying a point mutation in dipeptidylpeptidase 10 (Dpp10). Our data provide evidence that DPP10 might play a protective role in asthma.
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Affiliation(s)
- Youming Zhang
- Genomics Medicine Section, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Thanushiyan Poobalasingam
- Inflammation, Repair and Development Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Laura L Yates
- Inflammation, Repair and Development Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Simone A Walker
- Inflammation, Repair and Development Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Martin S Taylor
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3, 7BN
| | | | | | - Loukia Tsaprouni
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Ian M Adcock
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Clare M Lloyd
- Inflammation, Repair and Development Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - William O Cookson
- Genomics Medicine Section, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Miriam F Moffatt
- Genomics Medicine Section, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Charlotte H Dean
- Inflammation, Repair and Development Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK .,MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
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27
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Akita T, Aoto K, Kato M, Shiina M, Mutoh H, Nakashima M, Kuki I, Okazaki S, Magara S, Shiihara T, Yokochi K, Aiba K, Tohyama J, Ohba C, Miyatake S, Miyake N, Ogata K, Fukuda A, Matsumoto N, Saitsu H. De novo variants in CAMK2A and CAMK2B cause neurodevelopmental disorders. Ann Clin Transl Neurol 2018; 5:280-296. [PMID: 29560374 PMCID: PMC5846454 DOI: 10.1002/acn3.528] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022] Open
Abstract
Objective α (CAMK2A) and β (CAMK2B) isoforms of Calcium/calmodulin‐dependent protein kinase II (CaMKII) play a pivotal role in neuronal plasticity and in learning and memory processes in the brain. Here, we explore the possible involvement of α‐ and β‐CaMKII variants in neurodevelopmental disorders. Methods Whole‐exome sequencing was performed for 976 individuals with intellectual disability, developmental delay, and epilepsy. The effect of CAMK2A and CAMK2B variants on CaMKII structure and firing of neurons was evaluated by computational structural analysis, immunoblotting, and electrophysiological analysis. Results We identified a total of five de novo CAMK2A and CAMK2B variants in three and two individuals, respectively. Seizures were common to three individuals with CAMK2A variants. Using a minigene splicing assay, we demonstrated that a splice site variant caused skipping of exon 11 leading to an in‐frame deletion of the regulatory segment of CaMKIIα. By structural analysis, four missense variants are predicted to impair the interaction between the kinase domain and the regulatory segment responsible for the autoinhibition of its kinase activity. The Thr286/Thr287 phosphorylation as a result of release from autoinhibition was increased in three mutants when the mutants were stably expressed in Neuro‐2a neuroblastoma cells. Expression of a CaMKIIα mutant in primary hippocampal neurons significantly increased A‐type K+ currents, which facilitated spike repolarization of single action potentials. Interpretation Our data highlight the importance of CaMKIIα and CaMKIIβ and their autoinhibitory regulation in human brain function, and suggest the enhancement of A‐type K+ currents as a possible pathophysiological basis.
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Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Kazushi Aoto
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuhiro Kato
- Department of Pediatrics Showa University School of Medicine 1-5-8 Hatanodai, Shinagawa-ku Tokyo 142-8666 Japan
| | - Masaaki Shiina
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hiroki Mutoh
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuko Nakashima
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan.,Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Ichiro Kuki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shin Okazaki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shinichi Magara
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Takashi Shiihara
- Department of Neurology Gunma Children's Medical Center 779 Shimohakoda, Hokkitsu-machi Shibukawa Gunma 377-8577 Japan
| | - Kenji Yokochi
- Department of Pediatric Neurology Seirei-Mikatahara General Hospital 3453 Mikatahara-cho, Kita-ku Hamamatsu 433-8558 Japan.,Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Kaori Aiba
- Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Jun Tohyama
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Chihiro Ohba
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Satoko Miyatake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Noriko Miyake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Kazuhiro Ogata
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Atsuo Fukuda
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Naomichi Matsumoto
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hirotomo Saitsu
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
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Pelkey KA, Chittajallu R, Craig MT, Tricoire L, Wester JC, McBain CJ. Hippocampal GABAergic Inhibitory Interneurons. Physiol Rev 2017; 97:1619-1747. [PMID: 28954853 DOI: 10.1152/physrev.00007.2017] [Citation(s) in RCA: 495] [Impact Index Per Article: 70.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/16/2017] [Accepted: 05/26/2017] [Indexed: 12/11/2022] Open
Abstract
In the hippocampus GABAergic local circuit inhibitory interneurons represent only ~10-15% of the total neuronal population; however, their remarkable anatomical and physiological diversity allows them to regulate virtually all aspects of cellular and circuit function. Here we provide an overview of the current state of the field of interneuron research, focusing largely on the hippocampus. We discuss recent advances related to the various cell types, including their development and maturation, expression of subtype-specific voltage- and ligand-gated channels, and their roles in network oscillations. We also discuss recent technological advances and approaches that have permitted high-resolution, subtype-specific examination of their roles in numerous neural circuit disorders and the emerging therapeutic strategies to ameliorate such pathophysiological conditions. The ultimate goal of this review is not only to provide a touchstone for the current state of the field, but to help pave the way for future research by highlighting where gaps in our knowledge exist and how a complete appreciation of their roles will aid in future therapeutic strategies.
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Affiliation(s)
- Kenneth A Pelkey
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ramesh Chittajallu
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Michael T Craig
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ludovic Tricoire
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Jason C Wester
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Chris J McBain
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
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Hnoonual A, Thammachote W, Tim-Aroon T, Rojnueangnit K, Hansakunachai T, Sombuntham T, Roongpraiwan R, Worachotekamjorn J, Chuthapisith J, Fucharoen S, Wattanasirichaigoon D, Ruangdaraganon N, Limprasert P, Jinawath N. Chromosomal microarray analysis in a cohort of underrepresented population identifies SERINC2 as a novel candidate gene for autism spectrum disorder. Sci Rep 2017; 7:12096. [PMID: 28935972 PMCID: PMC5608768 DOI: 10.1038/s41598-017-12317-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 09/07/2017] [Indexed: 01/11/2023] Open
Abstract
Chromosomal microarray (CMA) is now recognized as the first-tier genetic test for detection of copy number variations (CNVs) in patients with autism spectrum disorder (ASD). The aims of this study were to identify known and novel ASD associated-CNVs and to evaluate the diagnostic yield of CMA in Thai patients with ASD. The Infinium CytoSNP-850K BeadChip was used to detect CNVs in 114 Thai patients comprised of 68 retrospective ASD patients (group 1) with the use of CMA as a second line test and 46 prospective ASD and developmental delay patients (group 2) with the use of CMA as the first-tier test. We identified 7 (6.1%) pathogenic CNVs and 22 (19.3%) variants of uncertain clinical significance (VOUS). A total of 29 patients with pathogenic CNVs and VOUS were found in 22% (15/68) and 30.4% (14/46) of the patients in groups 1 and 2, respectively. The difference in detected CNV frequencies between the 2 groups was not statistically significant (Chi square = 1.02, df = 1, P = 0.31). In addition, we propose one novel ASD candidate gene, SERINC2, which warrants further investigation. Our findings provide supportive evidence that CMA studies using population-specific reference databases in underrepresented populations are useful for identification of novel candidate genes.
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Affiliation(s)
- Areerat Hnoonual
- Graduate Program in Biomedical Sciences, Prince of Songkla University, Songkhla, Thailand
| | - Weerin Thammachote
- Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Thipwimol Tim-Aroon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Kitiwan Rojnueangnit
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine, Thammasart University, Pathumthani, Thailand
| | - Tippawan Hansakunachai
- Division of Child Development, Department of Pediatrics, Faculty of Medicine, Thammasart University, Pathumthani, Thailand
| | - Tasanawat Sombuntham
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Rawiwan Roongpraiwan
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Juthamas Worachotekamjorn
- Division of Child Development, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Jariya Chuthapisith
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Duangrurdee Wattanasirichaigoon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Nichara Ruangdaraganon
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pornprot Limprasert
- Division of Human Genetics, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
| | - Natini Jinawath
- Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. .,Integrative Computational Bioscience Center, Mahidol University, Salaya, Nakhon Pathom, Thailand.
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McNeilly AD, Gallagher JR, Huang JTJ, Ashford MLJ, McCrimmon RJ. High-Intensity Exercise as a Dishabituating Stimulus Restores Counterregulatory Responses in Recurrently Hypoglycemic Rodents. Diabetes 2017; 66:1696-1702. [PMID: 28270522 DOI: 10.2337/db16-1533] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/21/2017] [Indexed: 11/13/2022]
Abstract
Hypoglycemia is a major adverse effect of insulin therapy for people with type 1 diabetes (T1D). Profound defects in the normal counterregulatory response to hypoglycemia explain the frequency of hypoglycemia occurrence in T1D. Defective counterregulation results to a large extent from prior exposure to hypoglycemia per se, leading to a condition called impaired awareness of hypoglycemia (IAH), the cause of which is unknown. In the current study, we investigate the hypothesis that IAH develops through a special type of adaptive memory referred to as habituation. To test this hypothesis, we used a novel intense stimulus (high-intensity exercise) to demonstrate two classic features of a habituated response, namely dishabituation and response recovery. We demonstrate that after recurrent hypoglycemia the introduction of a novel dishabituating stimulus (a single burst of high-intensity exercise) in male Sprague-Dawley rats restores the defective hypoglycemia counterregulatory response. In addition, the rats showed an enhanced response to the novel stimulus (response recovery). We make the further observation using proteomic analysis of hypothalamic extracts that high-intensity exercise in recurrently hypoglycemic rats increases levels of a number of proteins linked with brain-derived neurotrophic factor signaling. These findings may lead to novel therapeutic approaches for individuals with T1D and IAH.
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Affiliation(s)
- Alison D McNeilly
- Division of Molecular and Clinical Medicine, University of Dundee, Dundee, U.K
| | | | - Jeffrey T-J Huang
- Division of Molecular and Clinical Medicine, University of Dundee, Dundee, U.K
| | - Michael L J Ashford
- Division of Molecular and Clinical Medicine, University of Dundee, Dundee, U.K
| | - Rory J McCrimmon
- Division of Molecular and Clinical Medicine, University of Dundee, Dundee, U.K.
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Abstract
Multiple types of voltage-gated K(+) and non-voltage-gated K(+) currents have been distinguished in mammalian cardiac myocytes based on differences in time-dependent and voltage-dependent properties and pharmacologic sensitivities. Many of the genes encoding voltage-gated K(+) (Kv) and non-voltage-gated K(+) (Kir and K2P) channel pore-forming and accessory subunits are expressed in the heart, and a variety of approaches have been, and continue to be, used to define the molecular determinants of native cardiac K(+) channels and to explore the molecular mechanisms controlling the diversity, regulation, and remodeling of these channels in the normal and diseased myocardium.
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Affiliation(s)
- Jeanne M Nerbonne
- Department of Internal Medicine, Washington University Medical School, 660 South Euclid Avenue, Box 8086, St Louis, MO 63110, USA; Department of Developmental Biology, Washington University Medical School, St Louis, MO 63110, USA.
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Shiina Y, Muto T, Zhang Z, Baihaqie A, Yoshizawa T, Lee HIJ, Park E, Tsukiji S, Takimoto K. Fly DPP10 acts as a channel ancillary subunit and possesses peptidase activity. Sci Rep 2016; 6:26290. [PMID: 27198182 PMCID: PMC4873792 DOI: 10.1038/srep26290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/28/2016] [Indexed: 01/04/2023] Open
Abstract
Mammalian DPP6 (DPPX) and DPP10 (DPPY) belong to a family of dipeptidyl peptidases, but lack enzyme activity. Instead, these proteins form complexes with voltage-gated K(+) channels in Kv4 family to control their gating and other properties. Here, we find that the fly DPP10 ortholog acts as an ancillary subunit of Kv4 channels and digests peptides. Similarly to mammalian DPP10, the fly ortholog tightly binds to rat Kv4.3 protein. The association causes negative shifts in voltage dependence of channel activation and steady state inactivation. It also results in faster inactivation and recovery from inactivation. In addition to its channel regulatory role, fly DPP10 exhibits significant dipeptidyl peptidase activity with Gly-Pro-MCA (glycyl-L-proline 4-methylcoumaryl-7-amide) as a substrate. Heterologously expressed Flag-tagged fly DPP10 and human DPP4 show similar Km values towards this substrate. However, fly DPP10 exhibits approximately a 6-times-lower relative kcat value normalized with anti-Flag immunoreactivity than human DPP4. These results demonstrate that fly DPP10 is a dual functional protein, controlling Kv4 channel gating and removing bioactive peptides.
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Affiliation(s)
- Yohei Shiina
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Tomohiro Muto
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Zhili Zhang
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Ahmad Baihaqie
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Takamasa Yoshizawa
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Hye-In J Lee
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Eulsoon Park
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Shinya Tsukiji
- Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-855, Japan.,Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-855, Japan
| | - Koichi Takimoto
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
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Identification of potential novel interaction partners of the sodium-activated potassium channels Slick and Slack in mouse brain. Biochem Biophys Rep 2015; 4:291-298. [PMID: 29124216 PMCID: PMC5669359 DOI: 10.1016/j.bbrep.2015.09.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/18/2015] [Accepted: 09/29/2015] [Indexed: 02/06/2023] Open
Abstract
The sodium-activated potassium channels Slick (Slo2.1, KCNT2) and Slack (Slo2.2, KCNT1) are paralogous channels of the Slo family of high-conductance potassium channels. Slick and Slack channels are widely distributed in the mammalian CNS and they play a role in slow afterhyperpolarization, generation of depolarizing afterpotentials and in setting and stabilizing the resting potential. In the present study we used a combined approach of (co)-immunoprecipitation studies, Western blot analysis, double immunofluorescence and mass spectrometric sequencing in order to investigate protein-protein interactions of the Slick and Slack channels. The data strongly suggest that Slick and Slack channels co-assemble into identical cellular complexes. Double immunofluorescence experiments revealed that Slick and Slack channels co-localize in distinct mouse brain regions. Moreover, we identified the small cytoplasmic protein beta-synuclein and the transmembrane protein 263 (TMEM 263) as novel interaction partners of both, native Slick and Slack channels. In addition, the inactive dipeptidyl-peptidase (DPP 10) and the synapse associated protein 102 (SAP 102) were identified as constituents of the native Slick and Slack channel complexes in the mouse brain. This study presents new insights into protein-protein interactions of native Slick and Slack channels in the mouse brain.
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Cheng CF, Wang WC, Huang CY, Du PH, Yang JH, Tsaur ML. Coexpression of auxiliary subunits KChIP and DPPL in potassium channel Kv4-positive nociceptors and pain-modulating spinal interneurons. J Comp Neurol 2015; 524:846-73. [PMID: 26239200 DOI: 10.1002/cne.23876] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 12/21/2022]
Abstract
Subthreshold A-type K(+) currents (ISA s) have been recorded from the somata of nociceptors and spinal lamina II excitatory interneurons, which sense and modulate pain, respectively. Kv4 channels are responsible for the somatodendritic ISA s. Accumulative evidence suggests that neuronal Kv4 channels are ternary complexes including pore-forming Kv4 subunits and two types of auxiliary subunits: K(+) channel-interacting proteins (KChIPs) and dipeptidyl peptidase-like proteins (DPPLs). Previous reports have shown Kv4.3 in a subset of nonpeptidergic nociceptors and Kv4.2/Kv4.3 in certain spinal lamina II excitatory interneurons. However, whether and which KChIP and DPPL are coexpressed with Kv4 in these ISA -expressing pain-related neurons is unknown. In this study we mapped the protein distribution of KChIP1, KChIP2, KChIP3, DPP6, and DPP10 in adult rat dorsal root ganglion (DRG) and spinal cord by immunohistochemistry. In the DRG, we found colocalization of KChIP1, KChIP2, and DPP10 in the somatic surface and cytoplasm of Kv4.3(+) nociceptors. KChIP3 appears in most Aβ and Aδ sensory neurons as well as a small population of peptidergic nociceptors, whereas DPP6 is absent in sensory neurons. In the spinal cord, KChIP1 is coexpressed with Kv4.3 in the cell bodies of a subset of lamina II excitatory interneurons, while KChIP1, KChIP2, and DPP6 are colocalized with Kv4.2 and Kv4.3 in their dendrites. Within the dorsal horn, besides KChIP3 in the inner lamina II and lamina III, we detected DPP10 in most projection neurons, which transmit pain signal to brain. The results suggest the existence of Kv4/KChIP/DPPL ternary complexes in ISA -expressing nociceptors and pain-modulating spinal interneurons.
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Affiliation(s)
- Chau-Fu Cheng
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Wan-Chen Wang
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Chia-Yi Huang
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Po-Hau Du
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Jung-Hui Yang
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Meei-Ling Tsaur
- Institute of Neuroscience, Brain Research Center, National Yang-Ming University, Taipei, Taiwan
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Abriel H, Rougier JS, Jalife J. Ion channel macromolecular complexes in cardiomyocytes: roles in sudden cardiac death. Circ Res 2015; 116:1971-88. [PMID: 26044251 DOI: 10.1161/circresaha.116.305017] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The movement of ions across specific channels embedded on the membrane of individual cardiomyocytes is crucial for the generation and propagation of the cardiac electric impulse. Emerging evidence over the past 20 years strongly suggests that the normal electric function of the heart is the result of dynamic interactions of membrane ion channels working in an orchestrated fashion as part of complex molecular networks. Such networks work together with exquisite temporal precision to generate each action potential and contraction. Macromolecular complexes play crucial roles in transcription, translation, oligomerization, trafficking, membrane retention, glycosylation, post-translational modification, turnover, function, and degradation of all cardiac ion channels known to date. In addition, the accurate timing of each cardiac beat and contraction demands, a comparable precision on the assembly and organizations of sodium, calcium, and potassium channel complexes within specific subcellular microdomains, where physical proximity allows for prompt and efficient interaction. This review article, part of the Compendium on Sudden Cardiac Death, discusses the major issues related to the role of ion channel macromolecular assemblies in normal cardiac electric function and the mechanisms of arrhythmias leading to sudden cardiac death. It provides an idea of how these issues are being addressed in the laboratory and in the clinic, which important questions remain unanswered, and what future research will be needed to improve knowledge and advance therapy.
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Affiliation(s)
- Hugues Abriel
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - Jean-Sébastien Rougier
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - José Jalife
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.).
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36
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Kitazawa M, Kubo Y, Nakajo K. Kv4.2 and accessory dipeptidyl peptidase-like protein 10 (DPP10) subunit preferentially form a 4:2 (Kv4.2:DPP10) channel complex. J Biol Chem 2015. [PMID: 26209633 DOI: 10.1074/jbc.m115.646794] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kv4 is a member of the voltage-gated K(+) channel family and forms a complex with various accessory subunits. Dipeptidyl aminopeptidase-like protein (DPP) is one of the auxiliary subunits for the Kv4 channel. Although DPP has been well characterized and is known to increase the current amplitude and accelerate the inactivation and recovery from inactivation of Kv4 current, it remains to be determined how many DPPs bind to one Kv4 channel. To examine whether the expression level of DPP changes the biophysical properties of Kv4, we expressed Kv4.2 and DPP10 in different ratios in Xenopus oocytes and analyzed the currents under two-electrode voltage clamp. The current amplitude and the speed of recovery from inactivation of Kv4.2 changed depending on the co-expression level of DPP10. This raised the possibility that the stoichiometry of the Kv4.2-DPP10 complex is variable and affects the biophysical properties of Kv4.2. We next determined the stoichiometry of DPP10 alone by subunit counting using single-molecule imaging. Approximately 70% of the DPP10 formed dimers in the plasma membrane, and the rest existed as monomers in the absence of Kv4.2. We next determined the stoichiometry of the Kv4.2-DPP10 complex; Kv4.2-mCherry and mEGFP-DPP10 were co-expressed in different ratios and the stoichiometries of Kv4.2-DPP10 complexes were evaluated by the subunit counting method. The stoichiometry of the Kv4.2-DPP10 complex was variable depending on the relative expression level of each subunit, with a preference for 4:2 stoichiometry. This preference may come from the bulky dimeric structure of the extracellular domain of DPP10.
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Affiliation(s)
- Masahiro Kitazawa
- From the Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan and the Department of Physiological Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0155, Japan
| | - Yoshihiro Kubo
- From the Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan and the Department of Physiological Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0155, Japan
| | - Koichi Nakajo
- From the Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan and the Department of Physiological Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0155, Japan
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37
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38
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Turnow K, Metzner K, Cotella D, Morales MJ, Schaefer M, Christ T, Ravens U, Wettwer E, Kämmerer S. Interaction of DPP10a with Kv4.3 channel complex results in a sustained current component of human transient outward current Ito. Basic Res Cardiol 2015; 110:5. [PMID: 25600224 DOI: 10.1007/s00395-014-0457-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 11/21/2014] [Accepted: 12/09/2014] [Indexed: 01/19/2023]
Abstract
The sustained component of the K(+) outward current in human atrial myocytes is believed to be due to the slowly inactivating ultra-rapid potassium current I Kur and not to the fast inactivating transient outward current Ito. Here we provide evidence for contribution of Ito to this late current due to the effects of dipeptidyl peptidase-like protein (DPP) 10 (DPP10a) interacting with Kv4.3 channels. We studied the late current component of Ito in human atrial myocytes and CHO cells co-expressing Kv4.3 or Kv4.3/KChIP2 (control) and DPP proteins using voltage-clamp technique and a pharmacological approach. A voltage dependent and slowly inactivating late current (43% of peak amplitude) could be observed in atrial myocytes. We found a similar current in CHO cells expressing Kv4.3/KChIP2 + DPP10a, but not in cells co-expressing Kv4.3 + DPP or Kv4.3/KChIP2 + DPP6-S. Assuming that DPP10a influences atrial Ito, we detected DPP10 expression of three alternatively spliced mRNAs, DPP10 protein and colocalization of Kv4.3 and DPP10 proteins in human atrial myocytes. DPP10a did not affect properties of expressed Kv1.5 excluding a contribution to the sustained IKur in atrial cells. To test for the contribution of Kv4-based Ito on sustained K(+) outward currents in human atrial myocytes, we used 4-AP to block IKur, in combination with Heteropoda toxin 2 to block Kv4 channels. We could clearly separate an Ito fraction of about 19% contributing to the late current in atrial myocytes. Thus, the interaction of DPP10a, expressed in human atrium, with Kv4.3 channels generates a sustained current component of Ito, which may affect late repolarization phase of atrial action potentials.
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Affiliation(s)
- K Turnow
- Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany
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39
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Lin L, Long LK, Hatch MM, Hoffman DA. DPP6 domains responsible for its localization and function. J Biol Chem 2014; 289:32153-32165. [PMID: 25190807 DOI: 10.1074/jbc.m114.578070] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dipeptidyl peptidase-like protein 6 (DPP6) is an auxiliary subunit of the Kv4 family of voltage-gated K(+) channels known to enhance channel surface expression and potently accelerate their kinetics. DPP6 is a single transmembrane protein, which is structurally remarkable for its large extracellular domain. Included in this domain is a cysteine-rich motif, the function of which is unknown. Here we show that this cysteine-rich domain of DPP6 is required for its export from the ER and expression on the cell surface. Disulfide bridges formed at C349/C356 and C465/C468 of the cysteine-rich domain are necessary for the enhancement of Kv4.2 channel surface expression but not its interaction with Kv4.2 subunits. The short intracellular N-terminal and transmembrane domains of DPP6 associates with and accelerates the recovery from inactivation of Kv4.2, but the entire extracellular domain is necessary to enhance Kv4.2 surface expression and stabilization. Our findings show that the cysteine-rich domain of DPP6 plays an important role in protein folding of DPP6 that is required for transport of DPP6/Kv4.2 complexes out of the ER.
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Affiliation(s)
- Lin Lin
- Molecular Neurophysiology and Biophysics Section, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
| | - Laura K Long
- Molecular Neurophysiology and Biophysics Section, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Michael M Hatch
- Molecular Neurophysiology and Biophysics Section, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Dax A Hoffman
- Molecular Neurophysiology and Biophysics Section, Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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Jerng HH, Pfaffinger PJ. Modulatory mechanisms and multiple functions of somatodendritic A-type K (+) channel auxiliary subunits. Front Cell Neurosci 2014; 8:82. [PMID: 24723849 PMCID: PMC3973911 DOI: 10.3389/fncel.2014.00082] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/03/2014] [Indexed: 12/13/2022] Open
Abstract
Auxiliary subunits are non-conducting, modulatory components of the multi-protein ion channel complexes that underlie normal neuronal signaling. They interact with the pore-forming α-subunits to modulate surface distribution, ion conductance, and channel gating properties. For the somatodendritic subthreshold A-type potassium (ISA) channel based on Kv4 α-subunits, two types of auxiliary subunits have been extensively studied: Kv channel-interacting proteins (KChIPs) and dipeptidyl peptidase-like proteins (DPLPs). KChIPs are cytoplasmic calcium-binding proteins that interact with intracellular portions of the Kv4 subunits, whereas DPLPs are type II transmembrane proteins that associate with the Kv4 channel core. Both KChIPs and DPLPs genes contain multiple start sites that are used by various neuronal populations to drive the differential expression of functionally distinct N-terminal variants. In turn, these N-terminal variants generate tremendous functional diversity across the nervous system. Here, we focus our review on (1) the molecular mechanism underlying the unique properties of different N-terminal variants, (2) the shaping of native ISA properties by the concerted actions of KChIPs and DPLP variants, and (3) the surprising ways that KChIPs and DPLPs coordinate the activity of multiple channels to fine-tune neuronal excitability. Unlocking the unique contributions of different auxiliary subunit N-terminal variants may provide an important opportunity to develop novel targeted therapeutics to treat numerous neurological disorders.
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Affiliation(s)
- Henry H. Jerng
- Department of Neuroscience, Baylor College of MedicineHouston, TX, USA
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Jerng HH, Pfaffinger PJ. S-glutathionylation of an auxiliary subunit confers redox sensitivity to Kv4 channel inactivation. PLoS One 2014; 9:e93315. [PMID: 24675763 PMCID: PMC3968176 DOI: 10.1371/journal.pone.0093315] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 03/04/2014] [Indexed: 12/24/2022] Open
Abstract
Reactive oxygen species (ROS) regulate ion channels, modulate neuronal excitability, and contribute to the etiology of neurodegenerative disorders. ROS differentially suppress fast "ball-and-chain" N-type inactivation of cloned Kv1 and Kv3 potassium channels but not of Kv4 channels, likely due to a lack of reactive cysteines in Kv4 N-termini. Recently, we discovered that N-type inactivation of Kv4 channel complexes can be independently conferred by certain N-terminal variants of Kv4 auxiliary subunits (DPP6a, DPP10a). Here, we report that both DPP6a and DPP10a, like Kv subunits with redox-sensitive N-type inactivation, contain a highly conserved cysteine in their N-termini (Cys-13). To test if N-type inactivation mediated by DPP6a or DPP10a is redox sensitive, Xenopus oocyte recordings were performed to examine the effects of two common oxidants, tert-butyl hydroperoxide (tBHP) and diamide. Both oxidants markedly modulate DPP6a- or DPP10a-conferred N-type inactivation of Kv4 channels, slowing the overall inactivation and increasing the peak current. These functional effects are fully reversed by the reducing agent dithiothreitol (DTT) and appear to be due to a selective modulation of the N-type inactivation mediated by these auxiliary subunits. Mutation of DPP6a Cys-13 to serine eliminated the tBHP or diamide effects, confirming the importance of Cys-13 to the oxidative regulation. Biochemical studies designed to elucidate the underlying molecular mechanism show no evidence of protein-protein disulfide linkage formation following cysteine oxidation. Instead, using a biotinylated glutathione (BioGEE) reagent, we discovered that oxidation by tBHP or diamide leads to S-glutathionylation of Cys-13, suggesting that S-glutathionylation underlies the regulation of fast N-type inactivation by redox. In conclusion, our studies suggest that Kv4-based A-type current in neurons may show differential redox sensitivity depending on whether DPP6a or DPP10a is highly expressed, and that the S-glutathionylation mechanism may play a previously unappreciated role in mediating excitability changes and neuropathologies associated with ROS.
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Affiliation(s)
- Henry H. Jerng
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Paul J. Pfaffinger
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
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Kunjilwar K, Qian Y, Pfaffinger PJ. Functional stoichiometry underlying KChIP regulation of Kv4.2 functional expression. J Neurochem 2013; 126:462-72. [PMID: 23692269 DOI: 10.1111/jnc.12309] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/08/2013] [Accepted: 05/15/2013] [Indexed: 11/29/2022]
Abstract
K channel-interacting proteins (KChIPs) enhance functional expression of Kv4 channels by binding to an N-terminal regulatory region located in the first 40 amino acids of Kv4.2 that we call the functional expression regulating N-terminal (FERN) domain. Mutating two residues in the FERN domain to alanines, W8A and F11A, disrupts KChIP binding and regulation of Kv4.2 without eliminating the FERN domain's control of basal expression level or regulation by DPP6. When Kv4.2(W8A,F11A) is co-expressed with wild type Kv4.2 and KChIP3 subunits, a dominant negative effect is seen where the current expression is reduced to levels normally seen without KChIP addition. The dominant negative effect correlates with heteromultimeric channels remaining on intracellular membranes despite KChIP binding to non-mutant Kv4.2 subunits. In contrast, the deletion mutant Kv4.2(Δ1-40), eliminating both KChIP binding and the FERN domain, has no dominant negative effect even though the maximal conductance level is 5x lower than seen with KChIP3. The 5x increased expression seen with KChIP integration into the channel is fully apparent even when a reduced number of KChIP subunits are incorporated as long as all FERN domains are bound. Our results support the hypothesis that KChIPs enhances Kv4.2 functional expression by a 1 : 1 suppression of the N-terminal FERN domain and by producing additional positive regulatory effects on functional channel expression.
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Affiliation(s)
- Kumud Kunjilwar
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
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Tang YQ, Liang P, Zhou J, Lu Y, Lei L, Bian X, Wang K. Auxiliary KChIP4a suppresses A-type K+ current through endoplasmic reticulum (ER) retention and promoting closed-state inactivation of Kv4 channels. J Biol Chem 2013; 288:14727-41. [PMID: 23576435 DOI: 10.1074/jbc.m113.466052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K(+) channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1-4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12-17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19-21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation.
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Affiliation(s)
- Yi-Quan Tang
- Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Peking University School of Pharmaceutical Sciences, Beijing 100191, China
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Abstract
Dipeptidyl Peptidase-like Protein 6 (DPP6) is widely expressed in the brain where it co-assembles with Kv4 channels and KChIP auxiliary subunits to regulate the amplitude and functional properties of the somatodendritic A-current, ISA. Here we show that in cerebellar granule (CG) cells DPP6 also regulates resting membrane potential and input resistance by increasing the amplitude of the IK(SO) resting membrane current. Pharmacological analysis shows that DPP6 acts through the control of a channel with properties matching the K2P channel TASK-3. Heterologous expression and co-immunoprecipitation shows that DPP6 co-expression with TASK-3 results in the formation of a protein complex that enhances resting membrane potassium conductance. The co-regulation of resting and voltage-gated channels by DPP6 produces coordinate shifts in resting membrane potential and A-current gating that optimize the sensitivity of ISA inactivation gating to subthreshold fluctuations in resting membrane potential.
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Matsuyoshi H, Takimoto K, Yunoki T, Erickson VL, Tyagi P, Hirao Y, Wanaka A, Yoshimura N. Distinct cellular distributions of Kv4 pore-forming and auxiliary subunits in rat dorsal root ganglion neurons. Life Sci 2012; 91:258-63. [PMID: 22820170 DOI: 10.1016/j.lfs.2012.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/25/2012] [Accepted: 07/07/2012] [Indexed: 12/23/2022]
Abstract
AIMS Dorsal root ganglia contain heterogeneous populations of primary afferent neurons that transmit various sensory stimuli. This functional diversity may be correlated with differential expression of voltage-gated K(+) (Kv) channels. Here, we examine cellular distributions of Kv4 pore-forming and ancillary subunits that are responsible for fast-inactivating A-type K(+) current. MAIN METHODS Expression pattern of Kv α-subunit, β-subunit and auxiliary subunit was investigated using immunohistochemistry, in situ hybridization and RT-PCR technique. KEY FINDINGS The two pore-forming subunits Kv4.1 and Kv4.3 show distinct cellular distributions: Kv4.3 is predominantly in small-sized C-fiber neurons, whereas Kv4.1 is seen in DRG neurons in various sizes. Furthermore, the two classes of Kv4 channel auxiliary subunits are also distributed in different-sized cells. KChIP3 is the only significantly expressed Ca(2+)-binding cytosolic ancillary subunit in DRGs and present in medium to large-sized neurons. The membrane-spanning auxiliary subunit DPP6 is seen in a large number of DRG neurons in various sizes, whereas DPP10 is restricted in small-sized neurons. SIGNIFICANCE Distinct combinations of Kv4 pore-forming and auxiliary subunits may constitute A-type channels in DRG neurons with different physiological roles. Kv4.1 subunit, in combination with KChIP3 and/or DPP6, form A-type K(+) channels in medium to large-sized A-fiber DRG neurons. In contrast, Kv4.3 and DPP10 may contribute to A-type K(+) current in non-peptidergic, C-fiber somatic afferent neurons.
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Affiliation(s)
- Hiroko Matsuyoshi
- Department of Physiology II, Nara Medical University, Kashihara, Nara, Japan
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Jerng HH, Pfaffinger PJ. Incorporation of DPP6a and DPP6K variants in ternary Kv4 channel complex reconstitutes properties of A-type K current in rat cerebellar granule cells. PLoS One 2012; 7:e38205. [PMID: 22675523 PMCID: PMC3366920 DOI: 10.1371/journal.pone.0038205] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 05/04/2012] [Indexed: 01/27/2023] Open
Abstract
Dipeptidyl peptidase-like protein 6 (DPP6) proteins co-assemble with Kv4 channel α-subunits and Kv channel-interacting proteins (KChIPs) to form channel protein complexes underlying neuronal somatodendritic A-type potassium current (ISA). DPP6 proteins are expressed as N-terminal variants (DPP6a, DPP6K, DPP6S, DPP6L) that result from alternative mRNA initiation and exhibit overlapping expression patterns. Here, we study the role DPP6 variants play in shaping the functional properties of ISA found in cerebellar granule (CG) cells using quantitative RT-PCR and voltage-clamp recordings of whole-cell currents from reconstituted channel complexes and native ISA channels. Differential expression of DPP6 variants was detected in rat CG cells, with DPP6K (41±3%)>DPP6a (33±3%)>>DPP6S (18±2%)>DPP6L (8±3%). To better understand how DPP6 variants shape native neuronal ISA, we focused on studying interactions between the two dominant variants, DPP6K and DPP6a. Although previous studies did not identify unique functional effects of DPP6K, we find that the unique N-terminus of DPP6K modulates the effects of KChIP proteins, slowing recovery and producing a negative shift in the steady-state inactivation curve. By contrast, DPP6a uses its distinct N-terminus to directly confer rapid N-type inactivation independently of KChIP3a. When DPP6a and DPP6K are co-expressed in ratios similar to those found in CG cells, their distinct effects compete in modulating channel function. The more rapid inactivation from DPP6a dominates during strong depolarization; however, DPP6K produces a negative shift in the steady-state inactivation curve and introduces a slow phase of recovery from inactivation. A direct comparison to the native CG cell ISA shows that these mixed effects are present in the native channels. Our results support the hypothesis that the precise expression and co-assembly of different auxiliary subunit variants are important factors in shaping the ISA functional properties in specific neuronal populations.
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Affiliation(s)
- Henry H Jerng
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America.
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Cotella D, Radicke S, Cipriani V, Cavaletto M, Merlin S, Follenzi A, Ravens U, Wettwer E, Santoro C, Sblattero D. N-glycosylation of the mammalian dipeptidyl aminopeptidase-like protein 10 (DPP10) regulates trafficking and interaction with Kv4 channels. Int J Biochem Cell Biol 2012; 44:876-85. [PMID: 22387313 DOI: 10.1016/j.biocel.2012.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/09/2012] [Accepted: 02/14/2012] [Indexed: 02/01/2023]
Abstract
The dipeptidyl aminopeptidase-like protein 10 (DPP10) is a type II transmembrane protein homologue to the serine protease DPPIV/CD26 but enzymatically inactive. In the mammalian brain, DPP10 forms a complex with voltage-gated potassium channels of the Kv4 family, regulating their cell surface expression and biophysical properties. DPP10 is a glycoprotein containing eight predicted N-glycosylation sites in the extracellular domain. In this study we investigated the role of N-glycosylation on DPP10 trafficking and functional activity. Using site-directed mutagenesis (N to Q) we showed that N-glycosylation occured at six positions. Glycosylation at these specific residues was necessary for DPP10 trafficking to the plasma membrane as observed by flow cytometry. The surface expression levels of the substitutions N90Q, N119Q, N257Q and N342Q were reduced by more than 60%. Hence the interaction with the Kv4.3/KChIP2a channel complex was disrupted preventing the hastening effect of wild type DPP10 on current kinetics. Interestingly, N257 was crucial for this function and its substitution to glutamine completely blocked DPP10 sorting to the cell surface and prevented DPP10 dimerization. In summary, we demonstrated that glycosylation was necessary for both DPP10 trafficking to the cell surface and functional interaction with Kv4 channels.
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Affiliation(s)
- Diego Cotella
- Department of Health Sciences and Interdisciplinary Research Centre on Autoimmune Diseases (IRCAD), Università del Piemonte Orientale A. Avogadro, Via Solaroli 17, 28100 Novara, Italy.
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Foeger NC, Norris AJ, Wren LM, Nerbonne JM. Augmentation of Kv4.2-encoded currents by accessory dipeptidyl peptidase 6 and 10 subunits reflects selective cell surface Kv4.2 protein stabilization. J Biol Chem 2012; 287:9640-50. [PMID: 22311982 DOI: 10.1074/jbc.m111.324574] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Rapidly activating and inactivating somatodendritic voltage-gated K(+) (Kv) currents, I(A), play critical roles in the regulation of neuronal excitability. Considerable evidence suggests that native neuronal I(A) channels function in macromolecular protein complexes comprising pore-forming (α) subunits of the Kv4 subfamily together with cytosolic, K(+) channel interacting proteins (KChIPs) and transmembrane, dipeptidyl peptidase 6 and 10 (DPP6/10) accessory subunits, as well as other accessory and regulatory proteins. Several recent studies have demonstrated a critical role for the KChIP subunits in the generation of native Kv4.2-encoded channels and that Kv4.2-KChIP complex formation results in mutual (Kv4.2-KChIP) protein stabilization. The results of the experiments here, however, demonstrate that expression of DPP6 in the mouse cortex is unaffected by the targeted deletion of Kv4.2 and/or Kv4.3. Further experiments revealed that heterologously expressed DPP6 and DPP10 localize to the cell surface in the absence of Kv4.2, and that co-expression with Kv4.2 does not affect total or cell surface DPP6 or DPP10 protein levels. In the presence of DPP6 or DPP10, however, cell surface Kv4.2 protein expression is selectively increased. Further addition of KChIP3 in the presence of DPP10 markedly increases total and cell surface Kv4.2 protein levels, compared with cells expressing only Kv4.2 and DPP10. Taken together, the results presented here demonstrate that the expression and localization of the DPP accessory subunits are independent of Kv4 α subunits and further that the DPP6/10 and KChIP accessory subunits independently stabilize the surface expression of Kv4.2.
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Affiliation(s)
- Nicholas C Foeger
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Nestor MW, Hoffman DA. Differential cycling rates of Kv4.2 channels in proximal and distal dendrites of hippocampal CA1 pyramidal neurons. Hippocampus 2011; 22:969-80. [PMID: 21472817 DOI: 10.1002/hipo.20899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2010] [Indexed: 11/06/2022]
Abstract
The heterogeneous expression of voltage-gated channels in dendrites suggests that neurons perform local microdomain computations at different regions. It has been shown that A-type K(+) channels have a nonuniform distribution along the primary apical dendrite in CA1 pyramidal neurons, increasing with distance from the soma. Kv4.2 channels, which are responsible for the somatodendritic A-type K(+) current in CA1 pyramidal neurons, shape local synaptic input, and regulate the back-propagation of APs into dendrites. Experiments were performed to test the hypothesis that Kv4.2 channels are differentially trafficked at different regions along the apical dendrite during basal activity and upon stimulation in CA1 neurons. Proximal (50-150 μm from the soma, primary and oblique) and distal (>200 μm) apical dendrites were selected. The fluorescence recovery after photobleaching (FRAP) technique was used to measure basal cycling rates of EGFP-tagged Kv4.2 (Kv4.2g). We found that the cycling rate of Kv4.2 channels was one order of magnitude slower at both primary and oblique dendrites between 50 and 150 μm from the soma. Kv4.2 channel cycling increased significantly at 200 to 250 μm from the soma. Expression of a Kv4.2 mutant lacking a phosphorylation site for protein kinase-A (Kv4.2gS552A) abolished this distance-dependent change in channel cycling; demonstrating that phosphorylation by PKA underlies the increased mobility in distal dendrites. Neuronal stimulation by α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) treatment increased cycling of Kv4.2 channels significantly at distal sites only. This activity-dependent increase in Kv4.2 cycling at distal dendrites was blocked by expression of Kv4.2gS552A. These results indicate that distance-dependent Kv4.2 mobility is regulated by activity-dependent phosphorylation of Kv4.2 by PKA.
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Affiliation(s)
- Michael W Nestor
- Molecular Neurophysiology and Biophysics Unit, Laboratory of Cellular and Synaptic Neurophysiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892-3715, USA.
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Kanyshkova T, Broicher T, Meuth SG, Pape HC, Budde T. A-type K+ currents in intralaminar thalamocortical relay neurons. Pflugers Arch 2011; 461:545-56. [PMID: 21437601 DOI: 10.1007/s00424-011-0953-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 02/22/2011] [Indexed: 10/18/2022]
Abstract
Transient A-type K+ currents (I(A)) are known to influence the firing pattern of a number of thalamic cell types, but have not been investigated in intralaminar thalamocortical (TC) relay neurons yet. We therefore combined whole-cell patch-clamp techniques, PCR analysis, and immunohistochemistry to investigate the voltage-dependent and pharmacological properties of I(A) and to determine its molecular basis in TC neurons from the centrolateral, paracentral, and centromedial thalamic nuclei. I(A) revealed half-maximal (V (h)) activation and inactivation at about -17 and -67 mV, respectively. At a concentration of 5-10 mM 4-aminopyridine (4-AP) completely blocked I(A). Furthermore, I(A) was nearly unaffected by two sea anemone toxins (blood depressing substances 1 and 2, BDS1 and BDS2; 6-8% block at a concentration of 1 μM) but strongly sensitive to the K(V)4 channel blocker Heteropoda venatoria toxin 2 (HpTx2; about 45% block at a concentration of 5 μM). PCR screening revealed the expression of K(V)4.1-4.3, with strongest expression for K(V)4.2 and weak expression for K(V)4.1. Accordingly K(V)4.1 was not detected in immunohistochemical staining. Furthermore, K(V)4.2 and K(V)4.3 revealed mainly dendritic and somatic staining, respectively. Together with current clamp recordings, these findings point to a scenario where the fast transient I(A) in intralaminar TC neurons has a depolarized threshold at potentials negative to -50 mV, is substantially generated by K(V)4.2 and K(V)4.3 channels, allows prominent burst firing at hyperpolarized potentials, prevents the generation of high-threshold potentials, generates a delayed onset of firing at more depolarized potentials, and allows fast tonic firing.
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Affiliation(s)
- Tatyana Kanyshkova
- Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, 48149, Münster, Germany
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