1
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Kim ED, Wu X, Lee S, Tibbs GR, Cunningham KP, Di Zanni E, Perez ME, Goldstein PA, Accardi A, Larsson HP, Nimigean CM. Propofol rescues voltage-dependent gating of HCN1 channel epilepsy mutants. Nature 2024; 632:451-459. [PMID: 39085604 DOI: 10.1038/s41586-024-07743-z] [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: 09/25/2023] [Accepted: 06/20/2024] [Indexed: 08/02/2024]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels1 are essential for pacemaking activity and neural signalling2,3. Drugs inhibiting HCN1 are promising candidates for management of neuropathic pain4 and epileptic seizures5. The general anaesthetic propofol (2,6-di-iso-propylphenol) is a known HCN1 allosteric inhibitor6 with unknown structural basis. Here, using single-particle cryo-electron microscopy and electrophysiology, we show that propofol inhibits HCN1 by binding to a mechanistic hotspot in a groove between the S5 and S6 transmembrane helices. We found that propofol restored voltage-dependent closing in two HCN1 epilepsy-associated polymorphisms that act by destabilizing the channel closed state: M305L, located in the propofol-binding site in S5, and D401H in S6 (refs. 7,8). To understand the mechanism of propofol inhibition and restoration of voltage-gating, we tracked voltage-sensor movement in spHCN channels and found that propofol inhibition is independent of voltage-sensor conformational changes. Mutations at the homologous methionine in spHCN and an adjacent conserved phenylalanine in S6 similarly destabilize closing without disrupting voltage-sensor movements, indicating that voltage-dependent closure requires this interface intact. We propose a model for voltage-dependent gating in which propofol stabilizes coupling between the voltage sensor and pore at this conserved methionine-phenylalanine interface in HCN channels. These findings unlock potential exploitation of this site to design specific drugs targeting HCN channelopathies.
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Affiliation(s)
- Elizabeth D Kim
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Xiaoan Wu
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sangyun Lee
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Gareth R Tibbs
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Kevin P Cunningham
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
- School of Life Sciences, University of Westminster, London, UK
| | - Eleonora Di Zanni
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Marta E Perez
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Peter A Goldstein
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Alessio Accardi
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - H Peter Larsson
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA.
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA.
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA.
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2
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Magielski J, McSalley I, Parthasarathy S, McKee J, Ganesan S, Helbig I. Advances in big data and omics: Paving the way for discovery in childhood epilepsies. Curr Probl Pediatr Adolesc Health Care 2024; 54:101634. [PMID: 38825428 DOI: 10.1016/j.cppeds.2024.101634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The insights gained from big data and omics approaches have transformed the field of childhood genetic epilepsy. With an increasing number of individuals receiving genetic testing for seizures, we are provided with an opportunity to identify clinically relevant subgroups and extract meaningful observations from this large-scale clinical data. However, the volume of data from electronic medical records and omics (e.g., genomics, transcriptomics) is so vast that standardized methods, such as the Human Phenotype Ontology, are necessary for reliable and comprehensive characterization. Here, we explore the integration of clinical and omics data, highlighting how these approaches pave the way for discovery in childhood epilepsies.
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Affiliation(s)
- Jan Magielski
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Ian McSalley
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Shridhar Parthasarathy
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jillian McKee
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shiva Ganesan
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA; School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, 19014, USA
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19146, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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3
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De Meulemeester AS, Reid C, Auvin S, Carlen PL, Cole AJ, Szlendak R, Di Sapia R, Moshé SL, Sankar R, O'Brien TJ, Baulac S, Henshall DC, Akman Ö, Galanopoulou AS. WONOEP appraisal: Modeling early onset epilepsies. Epilepsia 2024. [PMID: 39042520 DOI: 10.1111/epi.18063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/25/2024]
Abstract
Epilepsy has a peak incidence during the neonatal to early childhood period. These early onset epilepsies may be severe conditions frequently associated with comorbidities such as developmental deficits and intellectual disability and, in a significant percentage of patients, may be medication-resistant. The use of adult rodent models in the exploration of mechanisms and treatments for early life epilepsies is challenging, as it ignores significant age-specific developmental differences. More recently, models developed in immature animals, such as rodent pups, or in three-dimensional organoids may more closely model aspects of the immature brain and could result in more translatable findings. Although models are not perfect, they may offer a more controlled screening platform in studies of mechanisms and treatments, which cannot be done in pediatric patient cohorts. On the other hand, more simplified models with higher throughput capacities are required to deal with the large number of epilepsy candidate genes and the need for new treatment options. Therefore, a combination of different modeling approaches will be beneficial in addressing the unmet needs of pediatric epilepsy patients. In this review, we summarize the discussions on this topic that occurred during the XVI Workshop on Neurobiology of Epilepsy, organized in 2022 by the Neurobiology Commission of the International League Against Epilepsy. We provide an overview of selected models of early onset epilepsies, discussing their advantages and disadvantages. Heterologous expression models provide initial functional insights, and zebrafish, rodent models, and brain organoids present increasingly complex platforms for modeling and validating epilepsy-related phenomena. Together, these models offer valuable insights into early onset epilepsies and accelerate hypothesis generation and therapy discovery.
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Affiliation(s)
- Ann-Sofie De Meulemeester
- Institut du Cerveau-Paris Brain Institute-ICM, Institut National de la Santé et de la Recherche Médicale (INSERM), CNRS, Sorbonne Université, Paris, France
- Laboratory for Molecular Biodiscovery, KU Leuven, Leuven, Belgium
| | - Christopher Reid
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Medicine, Epilepsy Research Centre, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - Stéphane Auvin
- Pediatric Neurology Department, CRMR Épilepsies Rares, EpiCARE member, AP-HP, Robert-Debré University Hospital, Paris, France
- INSERM NeuroDiderot, Université Paris Cité, Paris, France
- Institut Universitaire de France, Paris, France
| | - Peter L Carlen
- Krembil Research Institute, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Andrew J Cole
- MGH Epilepsy Service, Division of Clinical Neurophysiology, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Roza Szlendak
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
- Institut de Génomique Fonctionnelle, University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
| | - Rossella Di Sapia
- Department of Acute Brain and Cardiovascular Injury, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Isabelle Rapin Division of Child Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Raman Sankar
- Department of Neurology and Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Terence J O'Brien
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Stéphanie Baulac
- Institut du Cerveau-Paris Brain Institute-ICM, Institut National de la Santé et de la Recherche Médicale (INSERM), CNRS, Sorbonne Université, Paris, France
| | - David C Henshall
- FutureNeuro SFI Research Centre, Royal College of Surgeons in Ireland (RCSI) University of Medicine and Health Sciences, Dublin, Ireland
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland (RCSI) University of Medicine and Health Sciences, Dublin, Ireland
| | - Özlem Akman
- Department of Physiology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Turkey
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Isabelle Rapin Division of Child Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
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4
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Saponaro A, Krumbach JH, Chaves-Sanjuan A, Sharifzadeh AS, Porro A, Castelli R, Hamacher K, Bolognesi M, DiFrancesco D, Clarke OB, Thiel G, Moroni A. Structural determinants of ivabradine block of the open pore of HCN4. Proc Natl Acad Sci U S A 2024; 121:e2402259121. [PMID: 38917012 PMCID: PMC11228525 DOI: 10.1073/pnas.2402259121] [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: 02/07/2024] [Accepted: 05/26/2024] [Indexed: 06/27/2024] Open
Abstract
HCN1-4 channels are the molecular determinants of the If/Ih current that crucially regulates cardiac and neuronal cell excitability. HCN dysfunctions lead to sinoatrial block (HCN4), epilepsy (HCN1), and chronic pain (HCN2), widespread medical conditions awaiting subtype-specific treatments. Here, we address the problem by solving the cryo-EM structure of HCN4 in complex with ivabradine, to date the only HCN-specific drug on the market. Our data show ivabradine bound inside the open pore at 3 Å resolution. The structure unambiguously proves that Y507 and I511 on S6 are the molecular determinants of ivabradine binding to the inner cavity, while F510, pointing outside the pore, indirectly contributes to the block by controlling Y507. Cysteine 479, unique to the HCN selectivity filter (SF), accelerates the kinetics of block. Molecular dynamics simulations further reveal that ivabradine blocks the permeating ion inside the SF by electrostatic repulsion, a mechanism previously proposed for quaternary ammonium ions.
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Affiliation(s)
- Andrea Saponaro
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan 20133, Italy
| | - Jan H Krumbach
- Department of Physics, Technische Universität Darmstadt, Darmstadt 64289, Germany
- Department of Biology and Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt 64287, Germany
| | | | | | - Alessandro Porro
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Roberta Castelli
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Kay Hamacher
- Department of Physics, Technische Universität Darmstadt, Darmstadt 64289, Germany
- Department of Biology and Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt 64287, Germany
| | | | - Dario DiFrancesco
- Department of Biosciences, University of Milan, Milan 20133, Italy
- Institute of Biophysics-Milan, Consiglio Nazionale delle Ricerche, Milan 20133, Italy
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY 10032
- Irving Institute for Clinical and Translational Research, Columbia University, New York, NY 10032
| | - Gerhard Thiel
- Department of Biology and Centre for Synthetic Biology, Technische Universität Darmstadt, Darmstadt 64287, Germany
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan 20133, Italy
- Institute of Biophysics-Milan, Consiglio Nazionale delle Ricerche, Milan 20133, Italy
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5
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Zhao K, Li Y, Lai H, Niu R, Li H, He S, Su Z, Gui Y, Ren L, Yang X, Zhou L. Alterations in HCN1 expression and distribution during epileptogenesis in rats. Epilepsy Res 2024; 202:107355. [PMID: 38555654 DOI: 10.1016/j.eplepsyres.2024.107355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/10/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and hippocampus. Under normal physiological conditions, HCN1 plays a crucial role in the excitatory and inhibitory regulation of neuronal networks. In temporal lobe epilepsy, the expression of HCN1 is decreased in the hippocampi of both animal models and patients. However, whether HCN1 expression changes during epileptogenesis preceding spontaneous seizures remains unclear. OBJECTIVE The aim of this study was to determine whether the expression of HCN1 is altered during the epileptic prodromal phase, thereby providing evidence for its role in epileptogenesis. METHODS We utilized a cobalt wire-induced rat epilepsy model to observe changes in HCN1 during epileptogenesis and epilepsy. Additionally, we also compared HCN1 alterations in epileptogenic tissues between cobalt wire- and pilocarpine-induced epilepsy rat models. Long-term video EEG recordings were used to confirm seizures development. Transcriptional changes, translation, and distribution of HCN1 were assessed using high-throughput transcriptome sequencing, total protein extraction, membrane and cytoplasmic protein fractionation, western blotting, immunohistochemistry, and immunofluorescence techniques. RESULTS In the cobalt wire-induced rat epilepsy model during the epileptogenesis phase, total HCN1 mRNA and protein levels were downregulated. Specifically, the membrane expression of HCN1 was decreased, whereas cytoplasmic HCN1 expression showed no significant change. The distribution of HCN1 in the distal dendrites of neurons decreased. During the epilepsy period, similar HCN1 alterations were observed in the neocortex of rats with cobalt wire-induced epilepsy and hippocampus of rats with lithium pilocarpine-induced epilepsy, including downregulation of mRNA levels, decreased total protein expression, decreased membrane expression, and decreased distal dendrite expression. CONCLUSIONS Alterations in HCN1 expression and distribution are involved in epileptogenesis beyond their association with seizure occurrence. Similarities in HCN1 alterations observed in epileptogenesis-related tissues from different models suggest a shared pathophysiological pathway in epileptogenesis involving HCN1 dysregulation. Therefore, the upregulation of HCN1 expression in neurons, maintenance of the HCN1 membrane, and distal dendrite distribution in neurons may represent promising disease-modifying strategies in epilepsy.
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Affiliation(s)
- Ke Zhao
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China; Guangzhou National Laboratory, Guangzhou, China; Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China
| | - Yinchao Li
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | | | - Ruili Niu
- Guangzhou National Laboratory, Guangzhou, China
| | - Huifeng Li
- Guangzhou National Laboratory, Guangzhou, China
| | - Shipei He
- Guangzhou National Laboratory, Guangzhou, China
| | - Zhengwei Su
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Yue Gui
- Guangzhou National Laboratory, Guangzhou, China
| | - Lijie Ren
- Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China.
| | | | - Liemin Zhou
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.
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6
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Houdayer C, Phillips AM, Chabbert M, Bourreau J, Maroofian R, Houlden H, Richards K, Saadi NW, Dad'ová E, Van Bogaert P, Rupin M, Keren B, Charles P, Smol T, Riquet A, Pais L, O'Donnell-Luria A, VanNoy GE, Bayat A, Møller RS, Olofsson K, Abou Jamra R, Syrbe S, Dasouki M, Seaver LH, Sullivan JA, Shashi V, Alkuraya FS, Poss AF, Spence JE, Schnur RE, Forster IC, Mckenzie CE, Simons C, Wang M, Snell P, Kothur K, Buckley M, Roscioli T, Elserafy N, Dauriat B, Procaccio V, Henrion D, Lenaers G, Colin E, Verbeek NE, Van Gassen KL, Legendre C, Bonneau D, Reid CA, Howell KB, Ziegler A, Legros C. Mono and biallelic variants in HCN2 cause severe neurodevelopmental disorders. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.19.24303984. [PMID: 38562733 PMCID: PMC10984036 DOI: 10.1101/2024.03.19.24303984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Hyperpolarization activated Cyclic Nucleotide (HCN) gated channels are crucial for various neurophysiological functions, including learning and sensory functions, and their dysfunction are responsible for brain disorders, such as epilepsy. To date, HCN2 variants have only been associated with mild epilepsy and recently, one monoallelic missense variant has been linked to developmental and epileptic encephalopathy. Here, we expand the phenotypic spectrum of HCN2- related disorders by describing twenty-one additional individuals from fifteen unrelated families carrying HCN2 variants. Seventeen individuals had developmental delay/intellectual disability (DD/ID), two had borderline DD/ID, and one had borderline DD. Ten individuals had epilepsy with DD/ID, with median age of onset of 10 months, and one had epilepsy with normal development. Molecular diagnosis identified thirteen different pathogenic HCN2 variants, including eleven missense variants affecting highly conserved amino acids, one frameshift variant, and one in-frame deletion. Seven variants were monoallelic of which five occurred de novo, one was not maternally inherited, one was inherited from a father with mild learning disabilities, and one was of unknown inheritance. The remaining six variants were biallelic, with four homozygous and two compound heterozygous variants. Functional studies using two-electrode voltage-clamp recordings in Xenopus laevis oocytes were performed on three monoallelic variants, p.(Arg324His), p.(Ala363Val), and p.(Met374Leu), and three biallelic variants, p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp). The p.(Arg324His) variant induced a strong increase of HCN2 conductance, while p.(Ala363Val) and p.(Met374Leu) displayed dominant negative effects, leading to a partial loss of HCN2 channel function. By confocal imaging, we found that the p.(Leu377His), p.(Pro493Leu) and p.(Gly587Asp) pathogenic variants impaired membrane trafficking, resulting in a complete loss of HCN2 elicited currents in Xenopus oocytes. Structural 3D-analysis in depolarized and hyperpolarized states of HCN2 channels, revealed that the pathogenic variants p.(His205Gln), p.(Ser409Leu), p.(Arg324Cys), p.(Asn369Ser) and p.(Gly460Asp) modify molecular interactions altering HCN2 function. Taken together, our data broadens the clinical spectrum associated with HCN2 variants, and disclose that HCN2 is involved in developmental encephalopathy with or without epilepsy.
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7
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Harde E, Hierl M, Weber M, Waiz D, Wyler R, Wach JY, Haab R, Gundlfinger A, He W, Schnider P, Paina M, Rolland JF, Greiter-Wilke A, Gasser R, Reutlinger M, Dupont A, Roberts S, O'Connor EC, Bartels B, Hall BJ. Selective and brain-penetrant HCN1 inhibitors reveal links between synaptic integration, cortical function, and working memory. Cell Chem Biol 2024; 31:577-592.e23. [PMID: 38042151 DOI: 10.1016/j.chembiol.2023.11.004] [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: 06/29/2023] [Revised: 09/28/2023] [Accepted: 11/07/2023] [Indexed: 12/04/2023]
Abstract
Hyperpolarization-activated and cyclic-nucleotide-gated 1 (HCN1) ion channels are proposed to be critical for cognitive function through regulation of synaptic integration. However, resolving the precise role of HCN1 in neurophysiology and exploiting its therapeutic potential has been hampered by minimally selective antagonists with poor potency and limited in vivo efficiency. Using automated electrophysiology in a small-molecule library screen and chemical optimization, we identified a primary carboxamide series of potent and selective HCN1 inhibitors with a distinct mode of action. In cognition-relevant brain circuits, selective inhibition of native HCN1 produced on-target effects, including enhanced excitatory postsynaptic potential summation, while administration of a selective HCN1 inhibitor to rats recovered decrement working memory. Unlike prior non-selective HCN antagonists, selective HCN1 inhibition did not alter cardiac physiology in human atrial cardiomyocytes or in rats. Collectively, selective HCN1 inhibitors described herein unmask HCN1 as a potential target for the treatment of cognitive dysfunction in brain disorders.
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Affiliation(s)
- Eva Harde
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
| | - Markus Hierl
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Michael Weber
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - David Waiz
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Roger Wyler
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Jean-Yves Wach
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Rachel Haab
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Anja Gundlfinger
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Weiping He
- WuXi AppTec (Wuhan) Co., Ltd, 666 Gaoxin Road, Wuhan East Lake High-Tech Development Zone, Wuhan, Huibei, China
| | - Patrick Schnider
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | | | | | - Andrea Greiter-Wilke
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Rodolfo Gasser
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Michael Reutlinger
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Amanda Dupont
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Sonia Roberts
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Eoin C O'Connor
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
| | - Björn Bartels
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
| | - Benjamin J Hall
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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8
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Qi ZX, Yan Q, Fan XJ, Peng JY, Zhu HX, Jiang YM, Chen L, Zhuang QX. Role of HCN channels in the functions of basal ganglia and Parkinson's disease. Cell Mol Life Sci 2024; 81:135. [PMID: 38478096 PMCID: PMC10937777 DOI: 10.1007/s00018-024-05163-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 03/17/2024]
Abstract
Parkinson's disease (PD) is a motor disorder resulting from dopaminergic neuron degeneration in the substantia nigra caused by age, genetics, and environment. The disease severely impacts a patient's quality of life and can even be life-threatening. The hyperpolarization-activated cyclic nucleotide-gated (HCN) channel is a member of the HCN1-4 gene family and is widely expressed in basal ganglia nuclei. The hyperpolarization-activated current mediated by the HCN channel has a distinct impact on neuronal excitability and rhythmic activity associated with PD pathogenesis, as it affects the firing activity, including both firing rate and firing pattern, of neurons in the basal ganglia nuclei. This review aims to comprehensively understand the characteristics of HCN channels by summarizing their regulatory role in neuronal firing activity of the basal ganglia nuclei. Furthermore, the distribution and characteristics of HCN channels in each nucleus of the basal ganglia group and their effect on PD symptoms through modulating neuronal electrical activity are discussed. Since the roles of the substantia nigra pars compacta and reticulata, as well as globus pallidus externus and internus, are distinct in the basal ganglia circuit, they are individually described. Lastly, this investigation briefly highlights that the HCN channel expressed on microglia plays a role in the pathological process of PD by affecting the neuroinflammatory response.
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Affiliation(s)
- Zeng-Xin Qi
- Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China
- National Center for Neurological Disorders, Shanghai, 200030, China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai, 200030, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200030, China
| | - Qi Yan
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Xiu-Juan Fan
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Jian-Ya Peng
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Hui-Xian Zhu
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Yi-Miao Jiang
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China
| | - Liang Chen
- Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, 200030, China.
- National Center for Neurological Disorders, Shanghai, 200030, China.
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai, 200030, China.
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200030, China.
| | - Qian-Xing Zhuang
- Department of Physiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, 226001, Jiangsu, China.
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9
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Locubiche S, Ordóñez V, Abad E, Scotto di Mase M, Di Donato V, De Santis F. A Zebrafish-Based Platform for High-Throughput Epilepsy Modeling and Drug Screening in F0. Int J Mol Sci 2024; 25:2991. [PMID: 38474238 DOI: 10.3390/ijms25052991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/22/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
The zebrafish model has emerged as a reference tool for phenotypic drug screening. An increasing number of molecules have been brought from bench to bedside thanks to zebrafish-based assays over the last decade. The high homology between the zebrafish and the human genomes facilitates the generation of zebrafish lines carrying loss-of-function mutations in disease-relevant genes; nonetheless, even using this alternative model, the establishment of isogenic mutant lines requires a long generation time and an elevated number of animals. In this study, we developed a zebrafish-based high-throughput platform for the generation of F0 knock-out (KO) models and the screening of neuroactive compounds. We show that the simultaneous inactivation of a reporter gene (tyrosinase) and a second gene of interest allows the phenotypic selection of F0 somatic mutants (crispants) carrying the highest rates of mutations in both loci. As a proof of principle, we targeted genes associated with neurodevelopmental disorders and we efficiently generated de facto F0 mutants in seven genes involved in childhood epilepsy. We employed a high-throughput multiparametric behavioral analysis to characterize the response of these KO models to an epileptogenic stimulus, making it possible to employ kinematic parameters to identify seizure-like events. The combination of these co-injection, screening and phenotyping methods allowed us to generate crispants recapitulating epilepsy features and to test the efficacy of compounds already during the first days post fertilization. Since the strategy can be applied to a wide range of indications, this study paves the ground for high-throughput drug discovery and promotes the use of zebrafish in personalized medicine and neurotoxicity assessment.
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Affiliation(s)
- Sílvia Locubiche
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
- Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain
| | - Víctor Ordóñez
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | - Elena Abad
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | | | - Vincenzo Di Donato
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
| | - Flavia De Santis
- ZeClinics S.L., Carrer de Laureà Miró, 408-410, 08980 Sant Feliu de Llobregat, Spain
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10
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Yang Z, Kuang Z, Liao H, Gan S, Peng X, Yang H, Wu L. HCN1 pathogenic variants associated with childhood epilepsy in a cohort of Chinese patients. Epileptic Disord 2024; 26:90-97. [PMID: 38009841 DOI: 10.1002/epd2.20182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 11/29/2023]
Abstract
OBJECTIVE HCN ion channel family has a widespread expression in neurons, and recently, increasing studies have demonstrated their roles in epilepsies. METHODS Clinical data of the patients were gathered in a retrospective study. Exon sequencing was used for the patients with unexplained recurrent seizures and varying levels of developmental delay. RESULTS In this study, eight de novo variants of HCN1 genes were uncovered in eight patients, including six missense variants, one nonsense variant and one frameshift insertion variant; five of them were reported for the first time. The onset age for eight patients ranges from one month to one year. Their main clinical manifestations are epilepsy and varying degrees of developmental delay, and the main type of seizure is focal secondary generalized tonic-clonic seizure. Importantly, in our study, one case presented with a form of migrating focal seizure that has not been reported in the literature. Seizures from five of the eight children were effectively controlled with antiepileptic drugs including valproic acid, levetiracetam and oxcarbazepine. One child developed normally and four children developed mild delay. One child was treated with topiramate, and the convulsion was partially controlled and showed moderate to severe developmental delay. The antiepileptic treatment failed for the other two children, and the two children were treated with sodium valproate, oxcarbazepine, lamotrigine, chlorbazan, levetiracetam and nitrodiazepam successively, but their convulsions were not controlled and showed moderate to severe developmental delay. SIGNIFICANCE Our research reported eight variants in HCN1 gene causing epilepsy; among these variants, five variants were never reported before. HCN1-related epilepsy usually starts infantile period, and focal secondary generalized tonic-clonic seizure is the most common seizure type. Importantly, we reported the case with migrating focal seizure was rarely reported. Our study expanded both genotype and phenotype for HCN1-related epilepsy.
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Affiliation(s)
- Zhuanyi Yang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Zhuo Kuang
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Hongmei Liao
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Siyi Gan
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Xiaomei Peng
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Haiyan Yang
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Liwen Wu
- Department of Neurology, Hunan Children's Hospital, Changsha, China
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11
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Chancey JH, Ahmed AA, Guillén FI, Ghatpande V, Howard MA. Complex Synaptic and Intrinsic Interactions Disrupt Input/Output Functions in the Hippocampus of Scn1b Knock-Out Mice. J Neurosci 2023; 43:8562-8577. [PMID: 37845033 PMCID: PMC10711733 DOI: 10.1523/jneurosci.0786-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/21/2023] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Pathogenic variants in SCN1B have been linked to severe developmental epileptic encephalopathies including Dravet syndrome. Scn1b knock-out (KO) mice model SCN1B loss-of-function (LOF) disorders, demonstrating seizures, developmental delays, and early death. SCN1B encodes the protein β1, an ion channel auxiliary subunit that also has roles in cell adhesion, neurite outgrowth, and gene expression. The goal of this project is to better understand of how loss of Scn1b alters information processing in the brain, resulting in seizures and associated cognitive dysfunction. Using slice electrophysiology in the CA1 region of the hippocampus from male and female Scn1b KO mice and wild-type (WT) littermates, we found that processing of physiologically relevant patterned Schaffer collateral (SC) stimulation produces larger, prolonged depolarizations and increased spiking in KO neurons compared with WTs. KO neurons exhibit enhanced intrinsic excitability, firing more action potentials with current injection. Interestingly, SC stimulation produces smaller, more facilitating excitatory and IPSCs in KO pyramidal neurons, but larger postsynaptic potentials (PSPs) with the same stimulation. We also found reduced intrinsic firing of parvalbumin (PV)-expressing interneurons and disrupted recruitment of both parvalbumin-expressing and somatostatin (SST)-expressing interneurons in response to patterned synaptic stimulation. Neuronal information processing relies on the interplay between synaptic properties, intrinsic properties that amplify or suppress incoming synaptic signals, and firing properties that produce cellular output. We found changes at each of these levels in Scn1b KO pyramidal neurons, resulting in fundamentally altered cellular information processing in the hippocampus that likely contributes to the complex phenotypes of SCN1B-linked epileptic encephalopathies.SIGNIFICANCE STATEMENT Genetic developmental epileptic encephalopathies have limited treatment options, in part because of our lack of understanding of how genetic changes result in dysfunction at the cellular and circuit levels. SCN1B is a gene linked to Dravet syndrome and other developmental epileptic encephalopathies, and Scn1b knock-out (KO) mice phenocopy the human disease, allowing us to study underlying neurophysiological changes. Here, we found changes at all levels of neuronal information processing in brains lacking Scn1b, including intrinsic excitability, synaptic properties, and synaptic integration, resulting in greatly enhanced input/output functions of the hippocampus. Our study shows that loss of Scn1b results in a complex array of cellular and network changes that fundamentally alters information processing in the hippocampus.
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Affiliation(s)
- Jessica Hotard Chancey
- Departments of Neurology and Neuroscience, Center for Learning and Memory, Dell Medical School, University of Texas at Austin, Austin, Texas 78712
| | - Alisha A Ahmed
- Departments of Neurology and Neuroscience, Center for Learning and Memory, Dell Medical School, University of Texas at Austin, Austin, Texas 78712
| | - Fernando Isaac Guillén
- Departments of Neurology and Neuroscience, Center for Learning and Memory, Dell Medical School, University of Texas at Austin, Austin, Texas 78712
| | - Vighnesh Ghatpande
- Departments of Neurology and Neuroscience, Center for Learning and Memory, Dell Medical School, University of Texas at Austin, Austin, Texas 78712
| | - MacKenzie A Howard
- Departments of Neurology and Neuroscience, Center for Learning and Memory, Dell Medical School, University of Texas at Austin, Austin, Texas 78712
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12
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DiFrancesco JC, Ragona F, Murano C, Frosio A, Melgari D, Binda A, Calamaio S, Prevostini R, Mauri M, Canafoglia L, Castellotti B, Messina G, Gellera C, Previtali R, Veggiotti P, Milanesi R, Barbuti A, Solazzi R, Freri E, Granata T, Rivolta I. A novel de novo HCN2 loss-of-function variant causing developmental and epileptic encephalopathy treated with a ketogenic diet. Epilepsia 2023; 64:e222-e228. [PMID: 37746765 DOI: 10.1111/epi.17777] [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: 07/13/2023] [Revised: 09/20/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
Missense variants of hyperpolarization-activated, cyclic nucleotide-gated (HCN) ion channels cause variable phenotypes, ranging from mild generalized epilepsy to developmental and epileptic encephalopathy (DEE). Although variants of HCN1 are an established cause of DEE, those of HCN2 have been reported in generalized epilepsies. Here we describe the first case of DEE caused by the novel de novo heterozygous missense variant c.1379G>A (p.G460D) of HCN2. Functional characterization in transfected HEK293 cells and neonatal rat cortical neurons revealed that HCN2 p.G460D currents were strongly reduced compared to wild-type, consistent with a dominant negative loss-of-function effect. Immunofluorescence staining showed that mutant channels are retained within the cell and do not reach the membrane. Moreover, mutant HCN2 also affect HCN1 channels, by reducing the Ih current expressed by the HCN1-HCN2 heteromers. Due to the persistence of frequent seizures despite pharmacological polytherapy, the patient was treated with a ketogenic diet, with a significant and long-lasting reduction of episodes. In vitro experiments conducted in a ketogenic environment demonstrated that the clinical improvement observed with this dietary regimen was not mediated by a direct action on HCN2 activity. These results expand the clinical spectrum related to HCN2 channelopathies, further broadening our understanding of the pathogenesis of DEE.
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Affiliation(s)
| | - Francesca Ragona
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Carmen Murano
- School of Medicine and Surgery, University of Milano-Bicocca, Milan Center for Neuroscience (NeuroMI), Monza, Italy
| | - Anthony Frosio
- IMTC - Institute of Molecular and Translational Cardiology, San Donato Milanese, Italy
| | - Dario Melgari
- IMTC - Institute of Molecular and Translational Cardiology, San Donato Milanese, Italy
| | - Anna Binda
- School of Medicine and Surgery, University of Milano-Bicocca, Milan Center for Neuroscience (NeuroMI), Monza, Italy
| | - Serena Calamaio
- IMTC - Institute of Molecular and Translational Cardiology, San Donato Milanese, Italy
| | - Rachele Prevostini
- IMTC - Institute of Molecular and Translational Cardiology, San Donato Milanese, Italy
| | - Mario Mauri
- School of Medicine and Surgery, University of Milano-Bicocca, Milan Center for Neuroscience (NeuroMI), Monza, Italy
| | - Laura Canafoglia
- Integrated Diagnostics for Epilepsy, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Barbara Castellotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Giuliana Messina
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Cinzia Gellera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Roberto Previtali
- Pediatric Neurology Unit, V. Buzzi Hospital, University of Milan, Milan, Italy
| | | | - Raffaella Milanesi
- Department of Veterinary Medicine and Animal Science, University of Milan, Lodi, Italy
| | - Andrea Barbuti
- The Cell Physiology MiLab, Department of Biosciences, University of Milano, Milan, Italy
| | - Roberta Solazzi
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ilaria Rivolta
- School of Medicine and Surgery, University of Milano-Bicocca, Milan Center for Neuroscience (NeuroMI), Monza, Italy
- IMTC - Institute of Molecular and Translational Cardiology, San Donato Milanese, Italy
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13
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Hassan M, Shahzadi S, Yasir M, Chun W, Kloczkowski A. Computational prognostic evaluation of Alzheimer's drugs from FDA-approved database through structural conformational dynamics and drug repositioning approaches. Sci Rep 2023; 13:18022. [PMID: 37865690 PMCID: PMC10590448 DOI: 10.1038/s41598-023-45347-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023] Open
Abstract
Drug designing is high-priced and time taking process with low success rate. To overcome this obligation, computational drug repositioning technique is being promptly used to predict the possible therapeutic effects of FDA approved drugs against multiple diseases. In this computational study, protein modeling, shape-based screening, molecular docking, pharmacogenomics, and molecular dynamic simulation approaches have been utilized to retrieve the FDA approved drugs against AD. The predicted MADD protein structure was designed by homology modeling and characterized through different computational resources. Donepezil and galantamine were implanted as standard drugs and drugs were screened out based on structural similarities. Furthermore, these drugs were evaluated and based on binding energy (Kcal/mol) profiles against MADD through PyRx tool. Moreover, pharmacogenomics analysis showed good possible associations with AD mediated genes and confirmed through detail literature survey. The best 6 drug (darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar) further docked and analyzed their interaction behavior through hydrogen binding. Finally, MD simulation study were carried out on these drugs and evaluated their stability behavior by generating root mean square deviation and fluctuations (RMSD/F), radius of gyration (Rg) and soluble accessible surface area (SASA) graphs. Taken together, darifenacin, astemizole, tubocurarine, elacridar, sertindole and tariquidar displayed good lead like profile as compared with standard and can be used as possible therapeutic agent in the treatment of AD after in-vitro and in-vivo assessment.
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Affiliation(s)
- Mubashir Hassan
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA.
| | - Saba Shahzadi
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA
| | - Muhammad Yasir
- Department of Pharmacology, College of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Wanjoo Chun
- Department of Pharmacology, College of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Andrzej Kloczkowski
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, 43205, USA.
- Department of Pediatrics, The Ohio State University, Columbus, OH, 43205, USA.
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14
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Abdelsamad A, Kachhadia MP, Hassan T, Kumar L, Khan F, Kar I, Panta U, Zafar W, Sapna F, Varrassi G, Khatri M, Kumar S. Charting the Progress of Epilepsy Classification: Navigating a Shifting Landscape. Cureus 2023; 15:e46470. [PMID: 37927689 PMCID: PMC10624359 DOI: 10.7759/cureus.46470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 10/04/2023] [Indexed: 11/07/2023] Open
Abstract
Epilepsy, a neurological disorder characterized by recurrent seizures, has witnessed a remarkable transformation in its classification paradigm, driven by advances in clinical understanding, neuroimaging, and molecular genetics. This narrative review navigates the dynamic landscape of epilepsy classification, offering insights into recent developments, challenges, and the promising horizon. Historically, epilepsy classification relied heavily on clinical observations, categorizing seizures based on their phenomenology and presumed etiology. However, the field has profoundly shifted from a symptom-based approach to a more refined, multidimensional system. One pivotal aspect of this evolution is the integration of neuroimaging techniques, particularly magnetic resonance imaging (MRI) and functional imaging modalities. These tools have unveiled the intricate neural networks implicated in epilepsy, facilitating the identification of distinct brain abnormalities and the categorization of epilepsy subtypes based on structural and functional findings. Furthermore, the role of genetics has become increasingly prominent in epilepsy classification. Genetic discoveries have not only unraveled the molecular underpinnings of various epileptic syndromes but have also provided valuable diagnostic and prognostic insights. This narrative review delves into the expanding realm of genetic testing and its impact on tailoring treatment strategies to individual patients. As the classification landscape evolves, there are accompanying challenges. The narrative review underscores the transformative potential of artificial intelligence and machine learning in epilepsy classification. These technologies hold promise in automating the analysis of complex neuroimaging and genetic data, offering enhanced accuracy and efficiency in epilepsy diagnosis and classification. In conclusion, navigating the shifting landscape of epilepsy classification is a journey marked by progress, complexity, and the prospect of improved patient care. We are charting a course toward more precise diagnoses and tailored treatments by embracing advanced neuroimaging, genetics, and innovative technologies. As the field continues to evolve, collaborative efforts and a holistic understanding of epilepsy's diverse manifestations will be instrumental in harnessing the full potential of this dynamic landscape.
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Affiliation(s)
- Alaa Abdelsamad
- Research and Development, Michigan State University, East Lansing, USA
| | | | - Talha Hassan
- Internal Medicine, KEMU (King Edward Medical University) Mayo Hospital, Lahore, PAK
| | - Lakshya Kumar
- General Medicine, PDU (Pandit Dindayal Upadhyay) Medical College, Rajkot, IND
| | - Faisal Khan
- Medicine, Dow University of Health Sciences (DUHS), Karachi, PAK
| | - Indrani Kar
- Medicine, Lady Hardinge Medical College, New Delhi, IND
| | - Uttam Panta
- Medicine, Chitwan Medical College, Bharatpur, NPL
| | - Wirda Zafar
- Medicine, University of Medicine and Health Sciences, Toronto, CAN
| | - Fnu Sapna
- Pathology, Albert Einstein College of Medicine, New York, USA
| | | | - Mahima Khatri
- Medicine and Surgery, Dow University of Health Sciences (DUHS), Karachi, PAK
| | - Satesh Kumar
- Medicine and Surgery, Shaheed Mohtarma Benazir Bhutto Medical College, Karachi, PAK
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15
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Miguel Sanz C, Martinez Navarro M, Caballero Diaz D, Sanchez-Elexpuru G, Di Donato V. Toward the use of novel alternative methods in epilepsy modeling and drug discovery. Front Neurol 2023; 14:1213969. [PMID: 37719765 PMCID: PMC10501616 DOI: 10.3389/fneur.2023.1213969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/14/2023] [Indexed: 09/19/2023] Open
Abstract
Epilepsy is a chronic brain disease and, considering the amount of people affected of all ages worldwide, one of the most common neurological disorders. Over 20 novel antiseizure medications (ASMs) have been released since 1993, yet despite substantial advancements in our understanding of the molecular mechanisms behind epileptogenesis, over one-third of patients continue to be resistant to available therapies. This is partially explained by the fact that the majority of existing medicines only address seizure suppression rather than underlying processes. Understanding the origin of this neurological illness requires conducting human neurological and genetic studies. However, the limitation of sample sizes, ethical concerns, and the requirement for appropriate controls (many patients have already had anti-epileptic medication exposure) in human clinical trials underscore the requirement for supplemental models. So far, mammalian models of epilepsy have helped to shed light on the underlying causes of the condition, but the high costs related to breeding of the animals, low throughput, and regulatory restrictions on their research limit their usefulness in drug screening. Here, we present an overview of the state of art in epilepsy modeling describing gold standard animal models used up to date and review the possible alternatives for this research field. Our focus will be mainly on ex vivo, in vitro, and in vivo larval zebrafish models contributing to the 3R in epilepsy modeling and drug screening. We provide a description of pharmacological and genetic methods currently available but also on the possibilities offered by the continued development in gene editing methodologies, especially CRISPR/Cas9-based, for high-throughput disease modeling and anti-epileptic drugs testing.
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16
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Pisani F, Spagnoli C. What are the considerations when initiating treatment for epilepsy in children? Expert Rev Neurother 2023; 23:1081-1096. [PMID: 38032395 DOI: 10.1080/14737175.2023.2288107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
INTRODUCTION There is a very wide spectrum of epilepsies and developmental and epileptic encephalopathies that affect children, from self-limited forms, not necessarily requiring treatment, to severe drug-resistant ones. AREAS COVERED In this perspective, the authors discuss the main factors to consider before drug prescription in children, considering the most recent clinical research, including age, seizure type, epilepsy syndrome, etiology, efficacy and safety profile, comorbidities, gender, available formulations, costs and drug coverage, and regulatory issues. The literature search was conducted through a PubMed search on antiseizure medications for patients aged 0-18, with respect to each of the aforementioned factors, and by checking the reference lists of relevant papers. EXPERT OPINION The most expanding field of research and innovation for clinical practice is precision medicine, which addresses the holistic treatment of genetic epilepsies and developmental and epileptic encephalopathies. It achieves this by addressing their detrimental effects on synapses, neurotransmission, and cellular signaling pathways with the double aim to treat seizures and to rescue neurodevelopmental trajectories, but also the issue of adverse events and drug resistance through pharmacogenomics.
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Affiliation(s)
- Francesco Pisani
- Human Neurosciences Department, Sapienza University of Rome, Rome, Italy
| | - Carlotta Spagnoli
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
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17
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Kobayashi Y, Tohyama J, Akasaka N, Yamada K, Hojo M, Seki E, Miura M, Soma N, Ono T, Kato M, Nakashima M, Saitsu H, Matsumoto N. The HCN1 p.Ser399Pro variant causes epileptic encephalopathy with super-refractory status epilepticus. Hum Genome Var 2023; 10:20. [PMID: 37353494 PMCID: PMC10290089 DOI: 10.1038/s41439-023-00247-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 06/25/2023] Open
Abstract
HCN1 is one of four genes encoding hyperpolarization-activated cyclic nucleotide-gated channels. The phenotypic spectrum associated with HCN1 variants ranges from neonatal developmental and epileptic encephalopathy to idiopathic generalized epilepsy. We report a Japanese patient with repetitive focal seizures and super-refractory status epilepticus since early infancy caused by a de novo HCN1 variant, NM_021072.4, c.1195T>C, p.(Ser399Pro). This variant might have a dominant-negative effect on channel function, leading to severe epileptic encephalopathy.
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Affiliation(s)
- Yu Kobayashi
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Jun Tohyama
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan.
| | - Noriyuki Akasaka
- Department of Pediatrics, Niigata Prefecture Hamagumi Medical Rehabilitation Center for Disabled Children, Niigata, Japan
| | - Kei Yamada
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Moemi Hojo
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Eijun Seki
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Masaki Miura
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Noriko Soma
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Takeshi Ono
- Department of Pediatrics, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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18
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Crunelli V, David F, Morais TP, Lorincz ML. HCN channels and absence seizures. Neurobiol Dis 2023; 181:106107. [PMID: 37001612 DOI: 10.1016/j.nbd.2023.106107] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
Hyperpolarization-activation cyclic nucleotide-gated (HCN) channels were for the first time implicated in absence seizures (ASs) when an abnormal Ih (the current generated by these channels) was reported in neocortical layer 5 neurons of a mouse model. Genetic studies of large cohorts of children with Childhood Absence Epilepsy (where ASs are the only clinical symptom) have identified only 3 variants in HCN1 (one of the genes that code for the 4 HCN channel isoforms, HCN1-4), with one (R590Q) mutation leading to loss-of-function. Due to the multi-faceted effects that HCN channels exert on cellular excitability and neuronal network dynamics as well as their modulation by environmental factors, it has been difficult to identify the detailed mechanism by which different HCN isoforms modulate ASs. In this review, we systematically and critically analyze evidence from established AS models and normal non-epileptic animals with area- and time-selective ablation of HCN1, HCN2 and HCN4. Notably, whereas knockout of rat HCN1 and mouse HCN2 leads to the expression of ASs, the pharmacological block of all HCN channel isoforms abolishes genetically determined ASs. These seemingly contradictory results could be reconciled by taking into account the well-known opposite effects of Ih on cellular excitability and network function. Whereas existing evidence from mouse and rat AS models indicates that pan-HCN blockers may provide a novel approach for the treatment of human ASs, the development of HCN isoform-selective drugs would greatly contribute to current research on the role for these channels in ASs generation and maintenance as well as offer new potential clinical applications.
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Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK.
| | - Francois David
- Integrative Neuroscience and Cognition Center, Paris University, Paris, France
| | - Tatiana P Morais
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, Malta University, Msida, Malta
| | - Magor L Lorincz
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK; Department of Physiology, Szeged University, Szeged, Hungary.
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19
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McKenzie CE, Forster IC, Soh MS, Phillips AM, Bleakley LE, Russ-Hall SJ, Myers KA, Scheffer IE, Reid CA. Cation leak: a common functional defect causing HCN1 developmental and epileptic encephalopathy. Brain Commun 2023; 5:fcad156. [PMID: 37265603 PMCID: PMC10231804 DOI: 10.1093/braincomms/fcad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/27/2023] [Accepted: 05/15/2023] [Indexed: 06/03/2023] Open
Abstract
Pathogenic variants in HCN1 are an established cause of developmental and epileptic encephalopathy (DEE). To date, the stratification of patients with HCN1-DEE based on the biophysical consequence on channel function of a given variant has not been possible. Here, we analysed data from eleven patients carrying seven different de novo HCN1 pathogenic variants located in the transmembrane domains of the protein. All patients were diagnosed with severe disease including epilepsy and intellectual disability. The functional properties of the seven HCN1 pathogenic variants were assessed using two-electrode voltage-clamp recordings in Xenopus oocytes. All seven variants showed a significantly larger instantaneous current consistent with cation leak. The impact of each variant on other biophysical properties was variable, including changes in the half activation voltage and activation and deactivation kinetics. These data suggest that cation leak is an important pathogenic mechanism in HCN1-DEE. Furthermore, published mouse model and clinical case reports suggest that seizures are exacerbated by sodium channel blockers in patients with HCN1 variants that cause cation leak. Stratification of patients based on their 'cation leak' biophysical phenotype may therefore provide key information to guide clinical management of individuals with HCN1-DEE.
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Affiliation(s)
- Chaseley E McKenzie
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Ian C Forster
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Ming S Soh
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - A Marie Phillips
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
- School of Biosciences, University of Melbourne, Parkville, VIC 3052, Australia
| | - Lauren E Bleakley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Sophie J Russ-Hall
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia
| | - Kenneth A Myers
- Department of Pediatrics, Faculty of Medicine, McGill University, Montreal, Montreal, Quebec H4A 3J1, Canada
| | - Ingrid E Scheffer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia
- Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Parkville, VIC 3052, Australia
| | - Christopher A Reid
- Correspondence to: Christopher A. Reid The Florey Institute of Neuroscience and Mental Health, University of Melbourne 30 Royal Parade, Parkville, Victoria 3052, Australian E-mail:
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20
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Wojciechowski MN, Schreiber S, Jose J. A Novel Flow Cytometry-Based Assay for the Identification of HCN4 CNBD Ligands. Pharmaceuticals (Basel) 2023; 16:ph16050710. [PMID: 37242492 DOI: 10.3390/ph16050710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are promising therapeutic targets because of their association with the genesis of several diseases. The identification of selective compounds that alter cAMP-induced ion channel modulation by binding to the cyclic nucleotide-binding domain (CNBD) will facilitate HCN channel-specific drug development. In this study, a fast and protein purification-free ligand-binding approach with a surface-displayed HCN4 C-Linker-CNBD on E. coli is presented. 8-Fluo-cAMP ligand binding was monitored by single-cell analysis via flow cytometry, and a Kd-value of 173 ± 46 nM was determined. The Kd value was confirmed by ligand depletion analysis and equilibrium state measurements. Applying increasing concentrations of cAMP led to a concentration-dependent decrease in fluorescence intensity, indicating a displacement of 8-Fluo-cAMP. A Ki-value of 8.5 ± 2 µM was determined. The linear relationship of IC50 values obtained for cAMP as a function of ligand concentration confirmed the competitive binding mode: IC50: 13 ± 2 µM/16 ± 3 µM/23 ± 1 µM/27 ± 1 µM for 50 nM/150 nM/250 nM/500 nM 8-Fluo-cAMP. A similar competitive mode of binding was confirmed for 7-CH-cAMP, and an IC50 value of 230 ± 41 nM and a Ki of 159 ± 29 nM were determined. Two established drugs were tested in the assay. Ivabradine, an approved HCN channel pore blocker and gabapentin, is known to bind to HCN4 channels in preference to other isoforms with an unknown mode of action. As expected, ivabradine had no impact on ligand binding. In addition, gabapentin had no influence on 8-Fluo-cAMP's binding to HCN4-CNBD. This is the first indication that gabapentin is not interacting with this part of the HCN4 channel. The ligand-binding assay as described can be used to determine binding constants for ligands such as cAMP and derivatives. It could also be applied for the identification of new ligands binding to the HCN4-CNBD.
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Affiliation(s)
- Magdalena N Wojciechowski
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
| | - Sebastian Schreiber
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
| | - Joachim Jose
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, Pharmacampus, 48149 Münster, Germany
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21
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Guerra M, Medici V, Weatheritt R, Corvino V, Palacios D, Geloso MC, Farini D, Sette C. Fetal exposure to valproic acid dysregulates the expression of autism-linked genes in the developing cerebellum. Transl Psychiatry 2023; 13:114. [PMID: 37019889 PMCID: PMC10076313 DOI: 10.1038/s41398-023-02391-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 04/07/2023] Open
Abstract
Autism spectrum disorder (ASD) includes a set of highly heritable neurodevelopmental syndromes characterized by social and communication impairment, repetitive behaviour, and intellectual disability. Although mutations in multiple genes have been associated to ASD, most patients lack detectable genetic alterations. For this reason, environmental factors are commonly thought to also contribute to ASD aetiology. Transcriptome analyses have revealed that autistic brains possess distinct gene expression signatures, whose elucidation can provide insights about the mechanisms underlying the effects of ASD-causing genetic and environmental factors. Herein, we have identified a coordinated and temporally regulated programme of gene expression in the post-natal development of cerebellum, a brain area whose defects are strongly associated with ASD. Notably, this cerebellar developmental programme is significantly enriched in ASD-linked genes. Clustering analyses highlighted six different patterns of gene expression modulated during cerebellar development, with most of them being enriched in functional processes that are frequently dysregulated in ASD. By using the valproic acid mouse model of ASD, we found that ASD-linked genes are dysregulated in the developing cerebellum of ASD-like mice, a defect that correlates with impaired social behaviour and altered cerebellar cortical morphology. Moreover, changes in transcript levels were reflected in aberrant protein expression, indicating the functional relevance of these alterations. Thus, our work uncovers a complex ASD-related transcriptional programme regulated during cerebellar development and highlight genes whose expression is dysregulated in this brain area of an ASD mouse model.
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Affiliation(s)
- Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, Rome, Italy
- GSTeP-Organoids Research Core Facility, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Vanessa Medici
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, Rome, Italy
| | - Robert Weatheritt
- Garvan Institute of Medical Research, EMBL Australia, Darlinghurst, NSW, Australia
| | - Valentina Corvino
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, Rome, Italy
| | - Daniela Palacios
- Department of Life Science and Public Health, Section of Biology, Catholic University of the Sacred Hearth, Rome, Italy
| | - Maria Concetta Geloso
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, Rome, Italy
- GSTeP-Organoids Research Core Facility, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Donatella Farini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Hearth, Rome, Italy.
- GSTeP-Organoids Research Core Facility, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy.
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22
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Zhao D, Pinares-Garcia P, McKenzie CE, Bleakley LE, Forster IC, Wong VHY, Nguyen CTO, Scheffer IE, Reid CA, Bui BV. Retinal Dysfunction in a Mouse Model of HCN1 Genetic Epilepsy. J Neurosci 2023; 43:2199-2209. [PMID: 36813574 PMCID: PMC10039744 DOI: 10.1523/jneurosci.1615-22.2022] [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: 08/25/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 02/24/2023] Open
Abstract
Pathogenic variants in HCN1 are associated with a range of epilepsy syndromes including a developmental and epileptic encephalopathy. The recurrent de novo HCN1 pathogenic variant (M305L) results in a cation leak, allowing the flux of excitatory ions at potentials where the wild-type channels are closed. The Hcn1M294L mouse recapitulates patient seizure and behavioral phenotypes. As HCN1 channels are highly expressed in rod and cone photoreceptor inner segments, where they shape the light response, mutated channels are likely to impact visual function. Electroretinogram (ERG) recordings from male and female mice Hcn1M294L mice revealed a significant decrease in the photoreceptor sensitivity to light, as well as attenuated bipolar cell (P2) and retinal ganglion cell responses. Hcn1M294L mice also showed attenuated ERG responses to flickering lights. ERG abnormalities are consistent with the response recorded from a single female human subject. There was no impact of the variant on the structure or expression of the Hcn1 protein in the retina. In silico modeling of photoreceptors revealed that the mutated HCN1 channel dramatically reduced light-induced hyperpolarization, resulting in more Ca2+ flux during the response when compared with the wild-type situation. We propose that the light-induced change in glutamate release from photoreceptors during a stimulus will be diminished, significantly blunting the dynamic range of this response. Our data highlight the importance of HCN1 channels to retinal function and suggest that patients with HCN1 pathogenic variants are likely to have a dramatically reduced sensitivity to light and a limited ability to process temporal information.SIGNIFICANCE STATEMENT Pathogenic variants in HCN1 are emerging as an important cause of catastrophic epilepsy. HCN1 channels are ubiquitously expressed throughout the body, including the retina. Electroretinogram recordings from a mouse model of HCN1 genetic epilepsy showed a marked decrease in the photoreceptor sensitivity to light and a reduced ability to respond to high rates of light flicker. No morphologic deficits were noted. Simulation data suggest that the mutated HCN1 channel blunts light-induced hyperpolarization and consequently limits the dynamic range of this response. Our results provide insights into the role HCN1 channels play in retinal function as well as highlighting the need to consider retinal dysfunction in disease caused by HCN1 variants. The characteristic changes in the electroretinogram open the possibility of using this tool as a biomarker for this HCN1 epilepsy variant and to facilitate development of treatments.
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Affiliation(s)
- Da Zhao
- Department of Optometry and Vision Sciences, School of Health Sciences, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Parkville 3010, Victoria, Australia
| | - Paulo Pinares-Garcia
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Chaseley E McKenzie
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Lauren E Bleakley
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Ian C Forster
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, School of Health Sciences, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Parkville 3010, Victoria, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, School of Health Sciences, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Parkville 3010, Victoria, Australia
| | - Ingrid E Scheffer
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne/Austin Health, Heidelberg 3084, Victoria, Australia
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville 3052, VIC Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville 3052, Victoria Australia
| | - Christopher A Reid
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville 3010, Victoria, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne/Austin Health, Heidelberg 3084, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, School of Health Sciences, Faculty of Medicine Dentistry and Health Sciences, University of Melbourne, Parkville 3010, Victoria, Australia
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23
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Rizzello E, Pimpinella D, Pignataro A, Titta G, Merenda E, Saviana M, Porcheddu G, Paolantoni C, Malerba F, Giorgi C, Curia G, Middei S, Marchetti C. Lamotrigine rescues neuronal alterations and prevents seizure-induced memory decline in an Alzheimer's disease mouse model. Neurobiol Dis 2023; 181:106106. [PMID: 37001613 DOI: 10.1016/j.nbd.2023.106106] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/17/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
Epilepsy is a comorbidity associated with Alzheimer's disease (AD), often starting many years earlier than memory decline. Investigating this association in the early pre-symptomatic stages of AD can unveil new mechanisms of the pathology as well as guide the use of antiepileptic drugs to prevent or delay hyperexcitability-related pathological effects of AD. We investigated the impact of repeated seizures on hippocampal memory and amyloid-β (Aβ) load in pre-symptomatic Tg2576 mice, a transgenic model of AD. Seizure induction caused memory deficits and an increase in oligomeric Aβ42 and fibrillary species selectively in pre-symptomatic transgenic mice, and not in their wildtype littermates. Electrophysiological patch-clamp recordings in ex vivo CA1 pyramidal neurons and immunoblots were carried out to investigate the neuronal alterations associated with the behavioral outcomes of Tg2576 mice. CA1 pyramidal neurons exhibited increased intrinsic excitability and lower hyperpolarization-activated Ih current. CA1 also displayed lower expression of the hyperpolarization-activated cyclic nucleotide-gated HCN1 subunit, a protein already identified as downregulated in the AD human proteome. The antiepileptic drug lamotrigine restored electrophysiological alterations and prevented both memory deficits and the increase in extracellular Aβ induced by seizures. Thus our study provides evidence of pre-symptomatic hippocampal neuronal alterations leading to hyperexcitability and associated with both higher susceptibility to seizures and to AD-specific seizure-induced memory impairment. Our findings also provide a basis for the use of the antiepileptic drug lamotrigine as a way to counteract acceleration of AD induced by seizures in the early phases of the pathology.
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24
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Altered EEG power spectrum, but not sleep-wake architecture, in HCN1 knockout mice. Behav Brain Res 2023; 437:114105. [PMID: 36089097 DOI: 10.1016/j.bbr.2022.114105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/29/2022] [Accepted: 09/05/2022] [Indexed: 11/20/2022]
Abstract
Sleep is a complex biological state characterized by large populations of neurons firing in a rhythmic or synchronized manner. HCN channels play a critical role in generating and sustaining synchronized neuronal firing and are involved in the actions of anaesthetics. However, the role of these channels in sleep-wakefulness per se has yet to be studied. We conducted polysomnographic recordings of Hcn1 constitutive knockout (Hcn1 KO) and wild-type (WT) mice in order to investigate the potential role of HCN1 channels in sleep/wake regulation. EEG and EMG data were analysed using the Somnivore™ machine learning algorithm. Time spent in each vigilance state, bout number and duration, and EEG power spectral activity were compared between genotypes. There were no significant differences in the time spent in wake, rapid eye movement (REM) or non-REM (NREM) sleep between Hcn1 KO and WT mice. Wake bout duration during the inactive phase was significantly shorter in Hcn1 KO mice whilst no other bout parameters were affected by genotype. Hcn1 KO mice showed a reduction in overall EEG power which was particularly prominent in the theta (5-9 Hz) and alpha (9-15 Hz) frequency bands and most evident during NREM sleep. Together these data suggest that HCN1 channels do not play a major role in sleep architecture or modulation of vigilance states. However, loss of these channels significantly alters underlying neuronal activity within these states which may have functional consequences.
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25
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Greeson KW, Crow KMS, Edenfield RC, Easley CA. Inheritance of paternal lifestyles and exposures through sperm DNA methylation. Nat Rev Urol 2023:10.1038/s41585-022-00708-9. [PMID: 36653672 DOI: 10.1038/s41585-022-00708-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2022] [Indexed: 01/19/2023]
Abstract
Many different lifestyle factors and chemicals present in the environment are a threat to the reproductive tracts of humans. The potential for parental preconception exposure to alter gametes and for these alterations to be passed on to offspring and negatively affect embryo growth and development is of concern. The connection between maternal exposures and offspring health is a frequent focus in epidemiological studies, but paternal preconception exposures are much less frequently considered and are also very important determinants of offspring health. Several environmental and lifestyle factors in men have been found to alter sperm epigenetics, which can regulate gene expression during early embryonic development. Epigenetic information is thought to be a mechanism that evolved for organisms to pass on information about their lived experiences to offspring. DNA methylation is a well-studied epigenetic regulator that is sensitive to environmental exposures in somatic cells and sperm. The continuous production of sperm from spermatogonial stem cells throughout a man's adult life and the presence of spermatogonial stem cells outside of the blood-testis barrier makes them susceptible to environmental insults. Furthermore, altered sperm DNA methylation patterns can be maintained throughout development and ultimately result in impairments, which could predispose offspring to disease. Innovations in human stem cell-based spermatogenic models can be used to elucidate the paternal origins of health and disease.
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Affiliation(s)
- Katherine W Greeson
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA.,Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - Krista M S Crow
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA.,Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - R Clayton Edenfield
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA.,Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - Charles A Easley
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, USA. .,Regenerative Bioscience Center, University of Georgia, Athens, GA, USA.
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26
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Inamdar SM, Lankford CK, Baker SA. Photoreceptor Ion Channels in Signaling and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:269-276. [PMID: 37440044 DOI: 10.1007/978-3-031-27681-1_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Photoreceptors (PRs) in the neural retina convert photon capture into an electrical signal that is communicated across a chemical synapse to second-order neurons in the retina and on through the rest of the visual pathway. This information is decoded in the visual cortex to create images. The activity of PRs depends on the concerted action of several voltage-gated ion channels that will be discussed in this chapter.
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Affiliation(s)
- Shivangi M Inamdar
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA.
| | - Colten K Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Sheila A Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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27
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Bleakley LE, McKenzie CE, Reid CA. Efficacy of antiseizure medication in a mouse model of HCN1 developmental and epileptic encephalopathy. Epilepsia 2023; 64:e1-e8. [PMID: 36300716 PMCID: PMC10953365 DOI: 10.1111/epi.17447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/25/2022] [Accepted: 10/25/2022] [Indexed: 01/21/2023]
Abstract
Acquisition of drug-sensitivity profiles is challenging in rare epilepsies. Anecdotal evidence suggests that antiseizure medications that block sodium channels as their primary mechanism of action exacerbate seizures in HCN1 developmental and epileptic encephalopathies (DEEs), whereas sodium valproate is effective for some patients. The Hcn1 M294L heterozygous knock-in (Hcn1M294L ) mouse carries the homologue of the recurrent gain-of-function HCN1 M305L pathogenic variant and recapitulates the seizure and some behavioral phenotypes observed in patients. We used this mouse model to study drug efficacy in HCN1 DEE. Hcn1M294L mice display epileptiform spiking on electrocorticography (ECoG), which we used as a quantifiable measure of drug effect. Phenytoin, lamotrigine, and retigabine significantly increased ECoG spike frequency, with lamotrigine and retigabine triggering seizures in a subset of the mice tested. In addition, there was a strong trend for carbamazepine to increase spiking. In contrast, levetiracetam, diazepam, sodium valproate, and ethosuximide all significantly reduced ECoG spike frequency. Drugs that reduced spiking did not cause any consistent ECoG spectral changes, whereas drugs that increased spiking all increased power in the slower delta and/or theta bands. These data provide a framework on which to build our understanding of gain-of-function HCN1 DEE pharmacosensitivity in the clinical setting.
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Affiliation(s)
- Lauren E. Bleakley
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Chaseley E. McKenzie
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
| | - Christopher A. Reid
- Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleVictoriaAustralia
- Epilepsy Research Centre, Department of Medicine, University of MelbourneAustin HealthHeidelbergVictoriaAustralia
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28
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Tiwari A, Meshram RJ, Kumar Singh R. Febrile Seizures in Children: A Review. Cureus 2022; 14:e31509. [DOI: 10.7759/cureus.31509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
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29
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Schrott R, Greeson KW, King D, Crow KMS, Easley CA, Murphy SK. Cannabis alters DNA methylation at maternally imprinted and autism candidate genes in spermatogenic cells. Syst Biol Reprod Med 2022; 68:357-369. [PMID: 35687495 PMCID: PMC10032331 DOI: 10.1080/19396368.2022.2073292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/18/2022] [Accepted: 04/23/2022] [Indexed: 10/18/2022]
Abstract
Cannabis use in the United States is increasing, with highest consumption among men at their peak reproductive years. We previously demonstrated widespread changes in sperm DNA methylation with cannabis exposure in humans and rats, including genes important in neurodevelopment. Here, we use an in vitro human spermatogenesis model to recapitulate chronic cannabis use and assess DNA methylation at imprinted and autism spectrum disorder (ASD) candidate genes in spermatogonial stem cell (SSC)- and spermatid-like cells. Methylation at maternally imprinted genes SGCE and GRB10 was significantly altered in SSC- and spermatid-like cells, respectively, while PEG3 was significantly differentially methylated in spermatid-like cells. Two of ten randomly selected ASD candidate genes, HCN1 and NR4A2, had significantly altered methylation with cannabis exposure in SSC-like cells. These results support our findings in human cohorts and provide a new tool with which to gain mechanistic insights into the association between paternal cannabis use and risk of ASD in offspring.
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Affiliation(s)
- Rose Schrott
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, 27701, USA
- Integrated Toxicology and Environmental Health Program, Nicholas School of the Environment, Duke University, Durham, NC, 27701, USA
| | - Katherine W. Greeson
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, 30602, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, 30602, USA
| | - Dillon King
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, 27701, USA
- Integrated Toxicology and Environmental Health Program, Nicholas School of the Environment, Duke University, Durham, NC, 27701, USA
| | - Krista M. Symosko Crow
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, 30602, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, 30602, USA
| | - Charles A. Easley
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA, 30602, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, 30602, USA
| | - Susan K. Murphy
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC, 27701, USA
- Integrated Toxicology and Environmental Health Program, Nicholas School of the Environment, Duke University, Durham, NC, 27701, USA
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Greenwood TA. Genetic Influences on Cognitive Dysfunction in Schizophrenia. Curr Top Behav Neurosci 2022; 63:291-314. [PMID: 36029459 DOI: 10.1007/7854_2022_388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Schizophrenia is a severe and debilitating psychotic disorder that is highly heritable and relatively common in the population. The clinical heterogeneity associated with schizophrenia is substantial, with patients exhibiting a broad range of deficits and symptom severity. Large-scale genomic studies employing a case-control design have begun to provide some biological insight. However, this strategy combines individuals with clinically diverse symptoms and ignores the genetic risk that is carried by many clinically unaffected individuals. Consequently, the majority of the genetic architecture underlying schizophrenia remains unexplained, and the pathways by which the implicated variants contribute to the clinically observable signs and symptoms are still largely unknown. Parsing the complex, clinical phenotype of schizophrenia into biologically relevant components may have utility in research aimed at understanding the genetic basis of liability. Cognitive dysfunction is a hallmark symptom of schizophrenia that is associated with impaired quality of life and poor functional outcome. Here, we examine the value of quantitative measures of cognitive dysfunction to objectively target the underlying neurobiological pathways and identify genetic variants and gene networks contributing to schizophrenia risk. For a complex disorder, quantitative measures are also more efficient than diagnosis, allowing for the identification of associated genetic variants with fewer subjects. Such a strategy supplements traditional analyses of schizophrenia diagnosis, providing the necessary biological insight to help translate genetic findings into actionable treatment targets. Understanding the genetic basis of cognitive dysfunction in schizophrenia may thus facilitate the development of novel pharmacological and procognitive interventions to improve real-world functioning.
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Affiliation(s)
- Tiffany A Greenwood
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
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31
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Iezzi D, Curti L, Ranieri G, Gerace E, Costa A, Ilari A, La Rocca A, Luceri C, D'Ambrosio M, Silvestri L, Scardigli M, Mannaioni G, Masi A. Acute rapamycin rescues the hyperexcitable phenotype of accumbal medium spiny neurons in the valproic acid rat model of autism spectrum disorder. Pharmacol Res 2022; 183:106401. [PMID: 35987482 DOI: 10.1016/j.phrs.2022.106401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/04/2022] [Accepted: 08/14/2022] [Indexed: 11/17/2022]
Abstract
We previously demonstrated that prenatal exposure to valproic acid (VPA), an environmental model of autism spectrum disorder (ASD), leads to a hyperexcitable phenotype associated with downregulation of inward-rectifying potassium currents in nucleus accumbens (NAc) medium spiny neurons (MSNs) of adolescent rats. Aberrant mTOR pathway function has been associated with autistic-like phenotypes in multiple animal models, including gestational exposure to VPA. The purpose of this work was to probe the involvement of the mTOR pathway in VPA-induced alterations of striatal excitability. Adolescent male Wistar rats prenatally exposed to VPA were treated acutely with the mTOR inhibitor rapamycin and used for behavioral tests, ex vivo brain slice electrophysiology, single-neuron morphometric analysis, synaptic protein quantification and gene expression analysis in the NAc. We report that postnatal rapamycin ameliorates the social deficit and reverts the abnormal excitability, but not the inward-rectifying potassium current defect, of accumbal MSNs. Synaptic transmission and neuronal morphology were largely unaffected by prenatal VPA exposure or postnatal rapamycin treatment. Transcriptome analysis revealed extensive deregulation of genes implied in neurodevelopmental disorders and ionic mechanisms exerted by prenatal VPA, which was partially reverted by postnatal rapamycin. The results of this work support the existence of antagonistic interaction between mTOR and VPA-induced pathways on social behavior, neurophysiological phenotype and gene expression profile, thus prompting further investigation of the mTOR pathway in the quest for specific therapeutic targets in ASD.
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Affiliation(s)
- D Iezzi
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy; Institut de Neurobiologie de la MEDiterranée - INMED, 163, Avenue de Luminy - Parc Scientifique, 13009, Marseille, France
| | - L Curti
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - G Ranieri
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - E Gerace
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - A Costa
- Università degli Studi di Firenze, Dipartimento di Scienze della Salute, viale Pieraccini 6, 50139, Firenze, Italy
| | - A Ilari
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - A La Rocca
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - C Luceri
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - M D'Ambrosio
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - L Silvestri
- Università degli Studi di Firenze, Dipartimento di Fisica e Astronomia, Via Sansone 1, 50019, Sesto Fiorentino, Italy; European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
| | - M Scardigli
- Università degli Studi di Firenze, Dipartimento di Fisica e Astronomia, Via Sansone 1, 50019, Sesto Fiorentino, Italy; European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
| | - G Mannaioni
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy
| | - A Masi
- Università degli Studi di Firenze, Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino - NEUROFARBA, viale Pieraccini 6, 50139, Firenze, Italy.
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Merseburg A, Kasemir J, Buss EW, Leroy F, Bock T, Porro A, Barnett A, Tröder SE, Engeland B, Stockebrand M, Moroni A, Siegelbaum S, Isbrandt D, Santoro B. Seizures, behavioral deficits and adverse drug responses in two new genetic mouse models of HCN1 epileptic encephalopathy. eLife 2022; 11:70826. [PMID: 35972069 PMCID: PMC9481245 DOI: 10.7554/elife.70826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
De novo mutations in voltage- and ligand-gated channels have been associated with an increasing number of cases of developmental and epileptic encephalopathies, which often fail to respond to classic antiseizure medications. Here, we examine two knock-in mouse models replicating de novo sequence variations in the HCN1 voltage-gated channel gene, p.G391D and p.M153I (Hcn1G380D/+ and Hcn1M142I/+ in mouse), associated with severe drug-resistant neonatal- and childhood-onset epilepsy, respectively. Heterozygous mice from both lines displayed spontaneous generalized tonic-clonic seizures. Animals replicating the p.G391D variant had an overall more severe phenotype, with pronounced alterations in the levels and distribution of HCN1 protein, including disrupted targeting to the axon terminals of basket cell interneurons. In line with clinical reports from patients with pathogenic HCN1 sequence variations, administration of the antiepileptic Na+ channel antagonists lamotrigine and phenytoin resulted in the paradoxical induction of seizures in both mouse lines, consistent with an effect to further impair inhibitory neuron function. We also show that these variants can render HCN1 channels unresponsive to classic antagonists, indicating the need to screen mutated channels to identify novel compounds with diverse mechanism of action. Our results underscore the necessity of tailoring effective therapies for specific channel gene variants, and how strongly validated animal models may provide an invaluable tool towards reaching this objective.
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Affiliation(s)
- Andrea Merseburg
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Jacquelin Kasemir
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eric W Buss
- Department of Neuroscience, Columbia University, New York, United States
| | - Felix Leroy
- Department of Neuroscience, Columbia University, New York, United States
| | - Tobias Bock
- Department of Neuroscience, Columbia University, New York, United States
| | | | - Anastasia Barnett
- Department of Neuroscience, Columbia University, New York, United States
| | - Simon E Tröder
- Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Birgit Engeland
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Malte Stockebrand
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy
| | - Steve Siegelbaum
- Department of Neuroscience, Columbia University, New York, United States
| | - Dirk Isbrandt
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Cologne, Germany
| | - Bina Santoro
- Department of Neuroscience, Columbia University, New York, United States
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Xie C, Liu F, He H, He F, Mao L, Wang X, Yin F, Peng J. Novel HCN1 Mutations Associated With Epilepsy and Impacts on Neuronal Excitability. Front Mol Neurosci 2022; 15:870182. [PMID: 35845605 PMCID: PMC9280081 DOI: 10.3389/fnmol.2022.870182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel plays a critical role in regulating the resting membrane potential and integrating synaptic transmission. Variants of HCN1 have been recognized as causes of epilepsy, and mutant HCN1 channels could act with loss-of-function (LOF), loss- and gain-of-function (LOF and GOF) and gain-of-function (GOF) mechanisms. However, phenotypes and pathogenesis of HCN1-related epilepsy are still poorly understood. This study enrolled five epileptic cases carrying five different HCN1 variants: two pathogenic variants (I380F and S710Rfs*71), two likely pathogenic variants (E240G and A395G), and a paternally inherited variant (V572A). Four variants were novel. Electrophysiological experiments revealed impaired biophysical properties of the identified mutants, including current densities and activation/deactivation kinetics. Moreover, three variants exerted effects on the biophysical properties of wild-type HCN1 channels in heterozygous conditions. Immunofluorescence experiments showed that two variants reduced the protein expression of HCN1channels in neurons. Neurons expressing E240G (GOF) variant showed increased input resistance. However, the variant of I380F (LOF) increased the neuronal firing rate, thus leading to neuronal hyperexcitability. In conclusion, the present study expands the genotypic and phenotypic spectrum of patients with HCN1-related epilepsy and clarifies the underlying mechanisms. We reported five new cases including four unreported likely/pathogenic variants. We provided assessments of biophysical function for each variant, which could help patients to receive individual therapy in the future. We confirmed that HCN1 variants contributed to neuronal hyperexcitability by regulating input resistance and the action potential firing rate, and we have shown that they can affect protein expression in neurons for the first time.
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Affiliation(s)
- Changning Xie
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Fangyun Liu
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Hailan He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Leilei Mao
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaole Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Development Disabilities Research Center, Changsha, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Development Disabilities Research Center, Changsha, China
- *Correspondence: Jing Peng,
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Lankford C, Houtman J, Baker SA. Identification of HCN1 as a 14-3-3 client. PLoS One 2022; 17:e0268335. [PMID: 35679272 PMCID: PMC9182292 DOI: 10.1371/journal.pone.0268335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 04/28/2022] [Indexed: 11/19/2022] Open
Abstract
Hyperpolarization activated cyclic nucleotide-gated channel 1 (HCN1) is expressed throughout the nervous system and is critical for regulating neuronal excitability, with mutations being associated with multiple forms of epilepsy. Adaptive modulation of HCN1 has been observed, as has pathogenic dysregulation. While the mechanisms underlying this modulation remain incompletely understood, regulation of HCN1 has been shown to include phosphorylation. A candidate phosphorylation-dependent regulator of HCN1 channels is 14-3-3. We used bioinformatics to identify three potential 14-3-3 binding sites in HCN1. We confirmed that 14-3-3 could pull down HCN1 from multiple tissue sources and used HEK293 cells to detail the interaction. Two sites in the intrinsically disordered C-terminus of HCN1 were necessary and sufficient for a phosphorylation-dependent interaction with 14-3-3. The same region of HCN1 containing the 14-3-3 binding peptides is required for phosphorylation-independent protein degradation. We propose a model in which phosphorylation of mouse S810 and S867 (human S789 and S846) recruits 14-3-3 to inhibit a yet unidentified factor signaling for protein degradation, thus increasing the half-life of HCN1.
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Affiliation(s)
- Colten Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Jon Houtman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, United States of America
| | - Sheila A. Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Pai VP, Levin M. HCN2 Channel-induced Rescue of Brain, Eye, Heart, and Gut Teratogenesis Caused by Nicotine, Ethanol, and Aberrant Notch Signaling. Wound Repair Regen 2022; 30:681-706. [PMID: 35662339 DOI: 10.1111/wrr.13032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/28/2022] [Accepted: 05/19/2022] [Indexed: 11/30/2022]
Abstract
Organogenesis is a complex process that can be disrupted by embryonic exposure to teratogens or mutation-induced alterations in signaling pathways, both of which result in organ mispatterning. Building on prior work in Xenopus laevis that showed that increased HCN2 ion channel activity rescues nicotine-induced brain & eye morphogenesis, we demonstrate much broader HCN2-based rescue of organ patterning defects. Induced HCN2 expression in both local or distant tissues can rescue CNS (brain & eye) as well as non-CNS (heart, & gut) organ defects induced by three different teratogenic conditions: nicotine exposure, ethanol exposure, or aberrant Notch protein. Rescue can also be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. Our results suggest that HCN2 (likely mediated by bioelectric signals) can be an effective regulator of organogenesis from all three germ layers (ectoderm, mesoderm, and endoderm) and reveal non-cell-autonomous influences on organ formation that work at considerable distance during embryonic development. These results suggest molecular bioelectric strategies for repair that could be explored in the future for regenerative medicine. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, Massachusetts, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, Massachusetts, USA
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Inflammation in pediatric epilepsies: Update on clinical features and treatment options. Epilepsy Behav 2022; 131:107959. [PMID: 33867302 DOI: 10.1016/j.yebeh.2021.107959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 02/08/2023]
Abstract
The role of inflammation is increasingly recognized in triggering or sustaining epileptic activity. In the last decades, increasing research has provided definite evidence to support the link between immunity, inflammatory process, and epilepsy. Neuro- and systemic inflammation play a pivotal role in driving epileptogenesis through different pathogenetic mechanisms: the activation of innate immunity in glia, neurons, and microvasculature, the brain mediated by blood-brain barrier (BBB) impairment, and the imbalance of pro- and anti-inflammatory molecules produced by both arms of immunity. More recently, research has focused on the adverse effects of maternal or early-life immune activation and cytokine imbalance on fetal neurodevelopment and postnatal epilepsy. A complex crosstalk between the immune and nervous system, and a crucial interplay of genetic, epigenetic, and environmental factors may influence structures and functions of the developing brain. A better understanding of the inflammatory process in promoting epilepsy implies that targeting specific pathways may be effective in seizure control. Multiple targets have been identified so far, and several antiseizure interventions are obtained by inhibiting inflammatory signaling or protecting/restoring BBB. All this evidence has changed the field of epilepsy research and neuropharmacology. Further developments and new treatments will rapidly emerge to improve seizure management in inflammation-related epilepsies. This article is part of the Special Issue "Severe Infantile Epilepsies".
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Lankford CK, Umino Y, Poria D, Kefalov V, Solessio E, Baker SA. Cone-Driven Retinal Responses Are Shaped by Rod But Not Cone HCN1. J Neurosci 2022; 42:4231-4249. [PMID: 35437278 PMCID: PMC9145265 DOI: 10.1523/jneurosci.2271-21.2022] [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: 11/16/2021] [Revised: 04/01/2022] [Accepted: 04/07/2022] [Indexed: 11/21/2022] Open
Abstract
Signal integration of converging neural circuits is poorly understood. One example is in the retina where the integration of rod and cone signaling is responsible for the large dynamic range of vision. The relative contribution of rods versus cones is dictated by a complex function involving background light intensity and stimulus temporal frequency. One understudied mechanism involved in coordinating rod and cone signaling onto the shared retinal circuit is the hyperpolarization activated current (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels expressed in rods and cones. Ih opposes membrane hyperpolarization driven by activation of the phototransduction cascade and modulates the strength and kinetics of the photoreceptor voltage response. We examined conditional knock-out (KO) of HCN1 from mouse rods using electroretinography (ERG). In the absence of HCN1, rod responses are prolonged in dim light which altered the response to slow modulation of light intensity both at the level of retinal signaling and behavior. Under brighter intensities, cone-driven signaling was suppressed. To our surprise, conditional KO of HCN1 from mouse cones had no effect on cone-mediated signaling. We propose that Ih is dispensable in cones because of the high level of temporal control of cone phototransduction. Thus, HCN1 is required for cone-driven retinal signaling only indirectly by modulating the voltage response of rods to limit their output.SIGNIFICANCE STATEMENT Hyperpolarization gated hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels carry a feedback current that helps to reset light-activated photoreceptors. Using conditional HCN1 knock-out (KO) mice we show that ablating HCN1 from rods allows rods to signal in bright light when they are normally shut down. Instead of enhancing vision this results in suppressing cone signaling. Conversely, ablating HCN1 from cones was of no consequence. This work provides novel insights into the integration of rod and cone signaling in the retina and challenges our assumptions about the role of HCN1 in cones.
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Affiliation(s)
- Colten K Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa 52242
| | - Yumiko Umino
- Center for Vision Research, Department of Ophthalmology and Visual Sciences, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Deepak Poria
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California 92697
| | - Vladimir Kefalov
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California 92697
- Department of Physiology and Biophysics, University of California, Irvine, California 92697
| | - Eduardo Solessio
- Center for Vision Research, Department of Ophthalmology and Visual Sciences, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Sheila A Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa 52242
- Department of Ophthalmology and Visual Sciences and Institute for Vision Research, University of Iowa, Iowa City, Iowa 52242
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Kessi M, Peng J, Duan H, He H, Chen B, Xiong J, Wang Y, Yang L, Wang G, Kiprotich K, Bamgbade OA, He F, Yin F. The Contribution of HCN Channelopathies in Different Epileptic Syndromes, Mechanisms, Modulators, and Potential Treatment Targets: A Systematic Review. Front Mol Neurosci 2022; 15:807202. [PMID: 35663267 PMCID: PMC9161305 DOI: 10.3389/fnmol.2022.807202] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Background Hyperpolarization-activated cyclic nucleotide-gated (HCN) current reduces dendritic summation, suppresses dendritic calcium spikes, and enables inhibitory GABA-mediated postsynaptic potentials, thereby suppressing epilepsy. However, it is unclear whether increased HCN current can produce epilepsy. We hypothesized that gain-of-function (GOF) and loss-of-function (LOF) variants of HCN channel genes may cause epilepsy. Objectives This systematic review aims to summarize the role of HCN channelopathies in epilepsy, update genetic findings in patients, create genotype–phenotype correlations, and discuss animal models, GOF and LOF mechanisms, and potential treatment targets. Methods The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, for all years until August 2021. Results We identified pathogenic variants of HCN1 (n = 24), HCN2 (n = 8), HCN3 (n = 2), and HCN4 (n = 6) that were associated with epilepsy in 74 cases (43 HCN1, 20 HCN2, 2 HCN3, and 9 HCN4). Epilepsy was associated with GOF and LOF variants, and the mechanisms were indeterminate. Less than half of the cases became seizure-free and some developed drug-resistant epilepsy. Of the 74 cases, 12 (16.2%) died, comprising HCN1 (n = 4), HCN2 (n = 2), HCN3 (n = 2), and HCN4 (n = 4). Of the deceased cases, 10 (83%) had a sudden unexpected death in epilepsy (SUDEP) and 2 (16.7%) due to cardiopulmonary failure. SUDEP affected more adults (n = 10) than children (n = 2). HCN1 variants p.M234R, p.C329S, p.V414M, p.M153I, and p.M305L, as well as HCN2 variants p.S632W and delPPP (p.719–721), were associated with different phenotypes. HCN1 p.L157V and HCN4 p.R550C were associated with genetic generalized epilepsy. There are several HCN animal models, pharmacological targets, and modulators, but precise drugs have not been developed. Currently, there are no HCN channel openers. Conclusion We recommend clinicians to include HCN genes in epilepsy gene panels. Researchers should explore the possible underlying mechanisms for GOF and LOF variants by identifying the specific neuronal subtypes and neuroanatomical locations of each identified pathogenic variant. Researchers should identify specific HCN channel openers and blockers with high binding affinity. Such information will give clarity to the involvement of HCN channelopathies in epilepsy and provide the opportunity to develop targeted treatments.
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Affiliation(s)
- Miriam Kessi
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- Department of Pediatrics, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Haolin Duan
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Hailan He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Baiyu Chen
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Juan Xiong
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Ying Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Lifen Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Guoli Wang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Karlmax Kiprotich
- Department of Epidemiology and Medical Statistics, School of Public Health, Moi University, Eldoret, Kenya
| | - Olumuyiwa A. Bamgbade
- Department of Anesthesiology and Pharmacology, University of British Columbia, Vancouver, BC, Canada
| | - Fang He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Intellectual and Developmental Disabilities Research Center, Changsha, China
- *Correspondence: Fei Yin
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Ding J, Wang L, Jin Z, Qiang Y, Li W, Wang Y, Zhu C, Jiang S, Xiao L, Hao X, Hu X, Li X, Wang F, Sun T. Do All Roads Lead to Rome? Genes Causing Dravet Syndrome and Dravet Syndrome-Like Phenotypes. Front Neurol 2022; 13:832380. [PMID: 35359639 PMCID: PMC8961694 DOI: 10.3389/fneur.2022.832380] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/26/2022] [Indexed: 11/16/2022] Open
Abstract
Background Dravet syndrome (DS) is a severe epileptic encephalopathy mainly caused by haploinsufficiency of the gene SCN1A, which encodes the voltage-gated sodium channel NaV1. 1 in the brain. While SCN1A mutations are known to be the primary cause of DS, other genes that may cause DS are poorly understood. Several genes with pathogenic mutations result in DS or DS-like phenotypes, which may require different drug treatment approaches. Therefore, it is urgent for clinicians, especially epilepsy specialists to fully understand these genes involved in DS in addition to SCN1A. Particularly for healthcare providers, a deep understanding of these pathogenic genes is useful in properly selecting and adjusting drugs in a more effective and timely manner. Objective The purpose of this study was to identify genes other than SCN1A that may also cause DS or DS-like phenotypes. Methods A comprehensive search of relevant Dravet syndrome and severe myoclonic epilepsy in infancy was performed in PubMed, until December 1, 2021. Two independent authors performed the screening for potentially eligible studies. Disagreements were decided by a third, more professional researcher or by all three. The results reported by each study were narratively summarized. Results A PubMed search yielded 5,064 items, and other sources search 12 records. A total of 29 studies published between 2009 and 2021 met the inclusion criteria. Regarding the included articles, seven studies on PCDH19, three on SCN2A, two on SCN8A, five on SCN1B, two on GABRA1, three on GABRB3, three on GABRG2, and three on STXBP1 were included. Only one study was recorded for CHD2, CPLX1, HCN1 and KCNA2, respectively. It is worth noting that a few articles reported on more than one epilepsy gene. Conclusion DS is not only identified in variants of SCN1A, but other genes such as PCDH19, SCN2A, SCN8A, SCN1B, GABRA1, GABRB3, GABRG2, KCNA2, CHD2, CPLX1, HCN1A, STXBP1 can also be involved in DS or DS-like phenotypes. As genetic testing becomes more widely available, more genes associated with DS and DS-like phenotypes may be identified and gene-based diagnosis of subtypes of phenotypes in this spectrum may improve the management of these diseases in the future.
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Affiliation(s)
- Jiangwei Ding
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Lei Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Zhe Jin
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Yuanyuan Qiang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Wenchao Li
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Yangyang Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Changliang Zhu
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Shucai Jiang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Lifei Xiao
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Xiaoyan Hao
- Department of Neurology, First Affiliated Hospital of Zhengzhou Universiy, Zhengzhou, China
| | - Xulei Hu
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Xinxiao Li
- Department of Neurosurgery, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Xinxiao Li
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Feng Wang
| | - Tao Sun
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
- *Correspondence: Tao Sun
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Mckenzie CE, Ho CJ, Forster IC, Soh MS, Phillips AM, Chang YC, Scheffer IE, Reid CA, Tsai MH. Impaired Color Recognition in HCN1 Epilepsy: A Single Case Report. Front Neurol 2022; 13:834252. [PMID: 35359652 PMCID: PMC8960314 DOI: 10.3389/fneur.2022.834252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
Variants in HCN1 are associated with a range of epilepsy syndromes including developmental and epileptic encephalopathies. Here we describe a child harboring a novel de novo HCN1 variant, E246A, in a child with epilepsy and mild developmental delay. By parental report, the child had difficulty in discriminating between colors implicating a visual deficit. This interesting observation may relate to the high expression of HCN1 channels in rod and cone photoreceptors where they play an integral role in shaping the light response. Functional analysis of the HCN1 E246A variant revealed a right shift in the voltage dependence of activation and slowing of the rates of activation and deactivation. The changes in the biophysical properties are consistent with a gain-of-function supporting the role of HCN1 E246A in disease causation. This case suggests that visual function, including color discrimination, should be carefully monitored in patients with diseases due to HCN1 pathogenic variants.
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Affiliation(s)
- Chaseley E. Mckenzie
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Chen-Jui Ho
- Division of Epilepsy, Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ian C. Forster
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Ming S. Soh
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - A. Marie Phillips
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Ying-Chao Chang
- Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ingrid E. Scheffer
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
- Department of Paediatrics, Murdoch Children's Research Institute, Royal Children's Hospital, University of Melbourne, Parkville, VIC, Australia
| | - Christopher A. Reid
- Early Development Division, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
| | - Meng-Han Tsai
- Division of Epilepsy, Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
- School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Genomics and Proteomics Core Laboratory, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
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Tocco C, Bertacchi M, Studer M. Structural and Functional Aspects of the Neurodevelopmental Gene NR2F1: From Animal Models to Human Pathology. Front Mol Neurosci 2022; 14:767965. [PMID: 34975398 PMCID: PMC8715095 DOI: 10.3389/fnmol.2021.767965] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/25/2021] [Indexed: 01/28/2023] Open
Abstract
The assembly and maturation of the mammalian brain result from an intricate cascade of highly coordinated developmental events, such as cell proliferation, migration, and differentiation. Any impairment of this delicate multi-factorial process can lead to complex neurodevelopmental diseases, sharing common pathogenic mechanisms and molecular pathways resulting in multiple clinical signs. A recently described monogenic neurodevelopmental syndrome named Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS) is caused by NR2F1 haploinsufficiency. The NR2F1 gene, coding for a transcriptional regulator belonging to the steroid/thyroid hormone receptor superfamily, is known to play key roles in several brain developmental processes, from proliferation and differentiation of neural progenitors to migration and identity acquisition of neocortical neurons. In a clinical context, the disruption of these cellular processes could underlie the pathogenesis of several symptoms affecting BBSOAS patients, such as intellectual disability, visual impairment, epilepsy, and autistic traits. In this review, we will introduce NR2F1 protein structure, molecular functioning, and expression profile in the developing mouse brain. Then, we will focus on Nr2f1 several functions during cortical development, from neocortical area and cell-type specification to maturation of network activity, hippocampal development governing learning behaviors, assembly of the visual system, and finally establishment of cortico-spinal descending tracts regulating motor execution. Whenever possible, we will link experimental findings in animal or cellular models to corresponding features of the human pathology. Finally, we will highlight some of the unresolved questions on the diverse functions played by Nr2f1 during brain development, in order to propose future research directions. All in all, we believe that understanding BBSOAS mechanisms will contribute to further unveiling pathophysiological mechanisms shared by several neurodevelopmental disorders and eventually lead to effective treatments.
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Affiliation(s)
- Chiara Tocco
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
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Zou D, Wang L, Liao J, Xiao H, Duan J, Zhang T, Li J, Yin Z, Zhou J, Yan H, Huang Y, Zhan N, Yang Y, Ye J, Chen F, Zhu S, Wen F, Guo J. Genome sequencing of 320 Chinese children with epilepsy: a clinical and molecular study. Brain 2021; 144:3623-3634. [PMID: 34145886 PMCID: PMC8719847 DOI: 10.1093/brain/awab233] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 05/25/2021] [Accepted: 06/05/2021] [Indexed: 02/05/2023] Open
Abstract
The aim of this study is to evaluate the diagnostic value of genome sequencing in children with epilepsy, and to provide genome sequencing-based insights into the molecular genetic mechanisms of epilepsy to help establish accurate diagnoses, design appropriate treatments and assist in genetic counselling. We performed genome sequencing on 320 Chinese children with epilepsy, and interpreted single-nucleotide variants and copy number variants of all samples. The complete pedigree and clinical data of the probands were established and followed up. The clinical phenotypes, treatments, prognoses and genotypes of the patients were analysed. Age at seizure onset ranged from 1 day to 17 years, with a median of 4.3 years. Pathogenic/likely pathogenic variants were found in 117 of the 320 children (36.6%), of whom 93 (29.1%) had single-nucleotide variants, 22 (6.9%) had copy number variants and two had both single-nucleotide variants and copy number variants. Single-nucleotide variants were most frequently found in SCN1A (10/95, 10.5%), which is associated with Dravet syndrome, followed by PRRT2 (8/95, 8.4%), which is associated with benign familial infantile epilepsy, and TSC2 (7/95, 7.4%), which is associated with tuberous sclerosis. Among the copy number variants, there were three with a length <25 kilobases. The most common recurrent copy number variants were 17p13.3 deletions (5/24, 20.8%), 16p11.2 deletions (4/24, 16.7%), and 7q11.23 duplications (2/24, 8.3%), which are associated with epilepsy, developmental retardation and congenital abnormalities. Four particular 16p11.2 deletions and two 15q11.2 deletions were considered to be susceptibility factors contributing to neurodevelopmental disorders associated with epilepsy. The diagnostic yield was 75.0% in patients with seizure onset during the first postnatal month, and gradually decreased in patients with seizure onset at a later age. Forty-two patients (13.1%) were found to be specifically treatable for the underlying genetic cause identified by genome sequencing. Three of them received corresponding targeted therapies and demonstrated favourable prognoses. Genome sequencing provides complete genetic diagnosis, thus enabling individualized treatment and genetic counselling for the parents of the patients. Genome sequencing is expected to become the first choice of methods for genetic testing of patients with epilepsy.
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Affiliation(s)
- Dongfang Zou
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Lin Wang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | | | - Jing Duan
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | | | | | | | - Jing Zhou
- BGI-Shenzhen, Shenzhen 518083, China
| | | | | | | | - Ying Yang
- BGI-Shenzhen, Shenzhen 518083, China
| | - Jingyu Ye
- BGI-Shenzhen, Shenzhen 518083, China
| | - Fang Chen
- BGI-Shenzhen, Shenzhen 518083, China
| | - Shida Zhu
- BGI-Shenzhen, Shenzhen 518083, China
| | - Feiqiu Wen
- Department of Hematology and Oncology, Shenzhen Children’s Hospital, Shenzhen, China
- Correspondence may also be addressed to: Feiqiu Wen Shenzhen Children’s Hospital No. 7019 Yitian Road, Shenzhen 518038 Guangdong, China E-mail:
| | - Jian Guo
- BGI-Shenzhen, Shenzhen 518083, China
- Correspondence to: Jian Guo BGI-Shenzhen, Beishan Industry Zone Shenzhen 518083, Guangdong, China E-mail:
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Xu C, Zhang Y, Gozal D, Carney P. Channelopathy of Dravet Syndrome and Potential Neuroprotective Effects of Cannabidiol. J Cent Nerv Syst Dis 2021; 13:11795735211048045. [PMID: 34992485 PMCID: PMC8724990 DOI: 10.1177/11795735211048045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dravet syndrome (DS) is a channelopathy, neurodevelopmental, epileptic encephalopathy characterized by seizures, developmental delay, and cognitive impairment that includes susceptibility to thermally induced seizures, spontaneous seizures, ataxia, circadian rhythm and sleep disorders, autistic-like behaviors, and premature death. More than 80% of DS cases are linked to mutations in genes which encode voltage-gated sodium channel subunits, SCN1A and SCN1B, which encode the Nav1.1α subunit and Nav1.1β1 subunit, respectively. There are other gene mutations encoding potassium, calcium, and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels related to DS. One-third of patients have pharmacoresistance epilepsy. DS is unresponsive to standard therapy. Cannabidiol (CBD), a non-psychoactive phytocannabinoid present in Cannabis, has been introduced for treating DS because of its anticonvulsant properties in animal models and humans, especially in pharmacoresistant patients. However, the etiological channelopathiological mechanism of DS and action mechanism of CBD on the channels are unclear. In this review, we summarize evidence of the direct and indirect action mechanism of sodium, potassium, calcium, and HCN channels in DS, especially sodium subunits. Some channels' loss-of-function or gain-of-function in inhibitory or excitatory neurons determine the balance of excitatory and inhibitory are associated with DS. A great variety of mechanisms of CBD anticonvulsant effects are focused on modulating these channels, especially sodium, calcium, and potassium channels, which will shed light on ionic channelopathy of DS and the precise molecular treatment of DS in the future.
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Affiliation(s)
- Changqing Xu
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Yumin Zhang
- Department of Anatomy, Physiology and Genetics; Department of Neuroscience, Uniformed Services University School of Medicine, Bethesda, MD, USA
| | - David Gozal
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Paul Carney
- Departments of Child Health and Neurology, School of Medicine, University of Missouri, Columbia, MO, USA
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Marini C, Giardino M. Novel treatments in epilepsy guided by genetic diagnosis. Br J Clin Pharmacol 2021; 88:2539-2551. [PMID: 34778987 DOI: 10.1111/bcp.15139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/22/2021] [Accepted: 11/04/2021] [Indexed: 12/21/2022] Open
Abstract
In recent years, precision medicine has emerged as a new paradigm for improved and more individualized patient care. Its key objective is to provide the right treatment, to the right patient at the right time, by basing medical decisions on individual characteristics, including specific genetic biomarkers. In order to realize this objective researchers and physicians must first identify the underlying genetic cause; over the last 10 years, advances in genetics have made this possible for several monogenic epilepsies. Through next generation techniques, a precise genetic aetiology is attainable in 30-50% of genetic epilepsies beginning in the paediatric age. While committed in such search for novel genes carrying disease-causing variants, progress in the study of experimental models of epilepsy has also provided a better understanding of the mechanisms underlying the condition. Such advances are already being translated into improving care, management and treatment of some patients. Identification of a precise genetic aetiology can already direct physicians to prescribe treatments correcting specific metabolic defects, avoid antiseizure medicines that might aggravate functional consequences of the disease-causing variant or select the drugs that counteract the underlying, genetically determined, functional disturbance. Personalized, tailored treatments should not just focus on how to stop seizures but possibly prevent their onset and cure the disorder, often consisting of seizures and its comorbidities including cognitive, motor and behaviour deficiencies. This review discusses the therapeutic implications following a specific genetic diagnosis and the correlation between genetic findings, pathophysiological mechanisms and tailored seizure treatment, emphasizing the impact on current clinical practice.
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Affiliation(s)
- Carla Marini
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Ancona, Ancona, Italy
| | - Maria Giardino
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Ancona, Ancona, Italy
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Specchio N, Di Micco V, Trivisano M, Ferretti A, Curatolo P. The epilepsy-autism spectrum disorder phenotype in the era of molecular genetics and precision therapy. Epilepsia 2021; 63:6-21. [PMID: 34741464 DOI: 10.1111/epi.17115] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 10/20/2021] [Accepted: 10/20/2021] [Indexed: 11/30/2022]
Abstract
Autism spectrum disorder (ASD) is frequently associated with infants with epileptic encephalopathy, and early interventions targeting social and cognitive deficits can have positive effects on developmental outcome. However, early diagnosis of ASD among infants with epilepsy is complicated by variability in clinical phenotypes. Commonality in both biological and molecular mechanisms have been suggested between ASD and epilepsy, such as occurs with tuberous sclerosis complex. This review summarizes the current understanding of causal mechanisms between epilepsy and ASD, with a particularly genetic focus. Hypothetical explanations to support the conjugation of the two conditions include abnormalities in synaptic growth, imbalance in neuronal excitation/inhibition, and abnormal synaptic plasticity. Investigation of the probable genetic basis has implemented many genes, although the main risk supports existing hypotheses in that these cluster to abnormalities in ion channels, synaptic function and structure, and transcription regulators, with the mammalian target of rapamycin (mTOR) pathway and "mTORpathies" having been a notable research focus. Experimental models not only have a crucial role in determining gene functions but are also useful instruments for tracing disease trajectory. Precision medicine from gene therapy remains a theoretical possibility, but more contemporary developments continue in molecular tests to aid earlier diagnoses and better therapeutic targeting.
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Valentina Di Micco
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Alessandro Ferretti
- Rare and Complex Epilepsy Unit, Division of Neurology, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
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Yu H, Gall B, Newman M, Hathaway Q, Brundage K, Ammer A, Mathers P, Siderovski D, Hull RW. Contribution of HCN1 variant to sinus bradycardia: A case report. J Arrhythm 2021; 37:1337-1347. [PMID: 34621433 PMCID: PMC8485797 DOI: 10.1002/joa3.12598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/08/2021] [Accepted: 06/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Missense mutations in the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel 4 (HCN4) are one of the genetic causes of cardiac sinus bradycardia. OBJECTIVE To investigate possible HCN4 channel mutation in a young patient with profound sinus bradycardia. METHODS Direct sequencing of HCN4 and whole-exome sequencing were performed on DNA samples from the indexed patient (P), the patient's son (PS), and a family unrelated healthy long-distance running volunteer (V). Resting heart rate was 31 bpm for P, 67 bpm for PS, and 50 bpm for V. Immunoblots, flow cytometry, and immunocytofluorescence confocal imaging were used to study cellular distribution of channel variants. Patch-clamp electrophysiology was used to investigate the properties of mutant HCN1 channels. RESULTS In P no missense mutations were found in the HCN4 gene; instead, we found two heterozygous variants in the HCN1 gene: deletion of an N-terminal glycine triplet (72GGG74, "N-del") and a novel missense variant, P851A, in the C-terminal region. N-del variant was found before and shared by PS. These two variations were not found in V. Compared to wild type, N-del and P851A reduced cell surface expression and negatively shifted voltage-activation with slower activation kinetics. CONCLUSION Decreased channel activity HCN1 mutant channel makes it unable to contribute to early depolarization of sinus node action potential, thus likely a main cause of the profound sinus bradycardia in this patient.
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Affiliation(s)
- Hangang Yu
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Bryan Gall
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Variant Curator at NateraSan CarlosCAUSA
| | - Mackenzie Newman
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Quincy Hathaway
- Department of Exercise PhysiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Kathleen Brundage
- Department of Microbiology, Immunology & Cell BiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Amanda Ammer
- Department of Microbiology, Immunology & Cell BiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - Peter Mathers
- Department of NeuroscienceSchool of MedicineWest Virginia UniversityMorgantownWVUSA
| | - David Siderovski
- Department of Physiology and PharmacologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Pharmacology & NeuroscienceUniversity of North TexasDentonTXUSA
| | - Robert W. Hull
- Department of CardiologySchool of MedicineWest Virginia UniversityMorgantownWVUSA
- Present address:
Department of CardiologyMon General HospitalMorgantownWVUSA
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A second S4 movement opens hyperpolarization-activated HCN channels. Proc Natl Acad Sci U S A 2021; 118:2102036118. [PMID: 34504015 DOI: 10.1073/pnas.2102036118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 11/18/2022] Open
Abstract
Rhythmic activity in pacemaker cells, as in the sino-atrial node in the heart, depends on the activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. As in depolarization-activated K+ channels, the fourth transmembrane segment S4 functions as the voltage sensor in hyperpolarization-activated HCN channels. But how the inward movement of S4 in HCN channels at hyperpolarized voltages couples to channel opening is not understood. Using voltage clamp fluorometry, we found here that S4 in HCN channels moves in two steps in response to hyperpolarizations and that the second S4 step correlates with gate opening. We found a mutation in sea urchin HCN channels that separate the two S4 steps in voltage dependence. The E356A mutation in S4 shifts the main S4 movement to positive voltages, but channel opening remains at negative voltages. In addition, E356A reveals a second S4 movement at negative voltages that correlates with gate opening. Cysteine accessibility and molecular models suggest that the second S4 movement opens up an intracellular crevice between S4 and S5 that would allow radial movement of the intracellular ends of S5 and S6 to open HCN channels.
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Developmental HCN channelopathy results in decreased neural progenitor proliferation and microcephaly in mice. Proc Natl Acad Sci U S A 2021; 118:2009393118. [PMID: 34429357 DOI: 10.1073/pnas.2009393118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The development of the cerebral cortex relies on the controlled division of neural stem and progenitor cells. The requirement for precise spatiotemporal control of proliferation and cell fate places a high demand on the cell division machinery, and defective cell division can cause microcephaly and other brain malformations. Cell-extrinsic and -intrinsic factors govern the capacity of cortical progenitors to produce large numbers of neurons and glia within a short developmental time window. In particular, ion channels shape the intrinsic biophysical properties of precursor cells and neurons and control their membrane potential throughout the cell cycle. We found that hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channel subunits are expressed in mouse, rat, and human neural progenitors. Loss of HCN channel function in rat neural stem cells impaired their proliferation by affecting the cell-cycle progression, causing G1 accumulation and dysregulation of genes associated with human microcephaly. Transgene-mediated, dominant-negative loss of HCN channel function in the embryonic mouse telencephalon resulted in pronounced microcephaly. Together, our findings suggest a role for HCN channel subunits as a part of a general mechanism influencing cortical development in mammals.
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Bleakley LE, McKenzie CE, Soh MS, Forster IC, Pinares-Garcia P, Sedo A, Kathirvel A, Churilov L, Jancovski N, Maljevic S, Berkovic SF, Scheffer IE, Petrou S, Santoro B, Reid CA. Cation leak underlies neuronal excitability in an HCN1 developmental and epileptic encephalopathy. Brain 2021; 144:2060-2073. [PMID: 33822003 PMCID: PMC8370418 DOI: 10.1093/brain/awab145] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/12/2021] [Accepted: 03/20/2021] [Indexed: 01/09/2023] Open
Abstract
Pathogenic variants in HCN1 are associated with developmental and epileptic encephalopathies. The recurrent de novo HCN1 M305L pathogenic variant is associated with severe developmental impairment and drug-resistant epilepsy. We engineered the homologue Hcn1 M294L heterozygous knock-in (Hcn1M294L) mouse to explore the disease mechanism underlying an HCN1 developmental and epileptic encephalopathy. The Hcn1M294L mouse recapitulated the phenotypic features of patients with the HCN1 M305L variant, including spontaneous seizures and a learning deficit. Active epileptiform spiking on the electrocorticogram and morphological markers typical of rodent seizure models were observed in the Hcn1M294L mouse. Lamotrigine exacerbated seizures and increased spiking, whereas sodium valproate reduced spiking, mirroring drug responses reported in a patient with this variant. Functional analysis in Xenopus laevis oocytes and layer V somatosensory cortical pyramidal neurons in ex vivo tissue revealed a loss of voltage dependence for the disease variant resulting in a constitutively open channel that allowed for cation 'leak' at depolarized membrane potentials. Consequently, Hcn1M294L layer V somatosensory cortical pyramidal neurons were significantly depolarized at rest. These neurons adapted through a depolarizing shift in action potential threshold. Despite this compensation, layer V somatosensory cortical pyramidal neurons fired action potentials more readily from rest. A similar depolarized resting potential and left-shift in rheobase was observed for CA1 hippocampal pyramidal neurons. The Hcn1M294L mouse provides insight into the pathological mechanisms underlying hyperexcitability in HCN1 developmental and epileptic encephalopathy, as well as being a preclinical model with strong construct and face validity, on which potential treatments can be tested.
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Affiliation(s)
- Lauren E Bleakley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Chaseley E McKenzie
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Ming S Soh
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Ian C Forster
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Paulo Pinares-Garcia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Alicia Sedo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Anirudh Kathirvel
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Leonid Churilov
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
- Melbourne Medical School, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nikola Jancovski
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Snezana Maljevic
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Samuel F Berkovic
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia
| | - Ingrid E Scheffer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia
- Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Parkville, Victoria 3052, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Bina Santoro
- Department of Neuroscience, The Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia
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Porro A, Abbandonato G, Veronesi V, Russo A, Binda A, Antolini L, Granata T, Castellotti B, Marini C, Moroni A, DiFrancesco JC, Rivolta I. Do the functional properties of HCN1 mutants correlate with the clinical features in epileptic patients? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:147-155. [PMID: 34310985 DOI: 10.1016/j.pbiomolbio.2021.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/14/2021] [Accepted: 07/20/2021] [Indexed: 10/20/2022]
Abstract
The altered function of the Hyperpolarization-activated Cyclic-Nucleotide-gated (HCN) ion channels plays an important role in the pathogenesis of epilepsy in humans. In particular, HCN1 missense mutations have been recently identified in patients with different epileptic phenotypes, varying from mild to severe. Their electrophysiological characterization shows that mutated channels can act both with loss-of-function and gain-of-function mechanisms of action, without an evident correlation with the phenotype. In search for a correlation between clinical features and biophysical properties of the mutations, in this work we considered sixteen HCN1 mutations, found in eighteen Early Infantile Epileptic Encephalopathy (EIEE) patients. Statistical analysis did not establish any significant correlation between the clinical parameters and the current properties of the mutant channels. The lack of significance of our results could depend on the small number of mutations analyzed, epilepsy-associated with certainty. With the progressive increase of Next Generation Sequencing in patients with early-onset epilepsy, it is expected that the number of patients with HCN1 mutations will grow steadily. Functional characterization of epilepsy-associated HCN1 mutations remains a fundamental tool for a better understanding of the pathogenetic mechanisms leading to the disease in humans.
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Affiliation(s)
| | | | - Valentina Veronesi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Alberto Russo
- Department of Biosciences, University of Milan, Milan, Italy.
| | - Anna Binda
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Laura Antolini
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Carla Marini
- Department of Child Neuropsychiatry, Children's Hospital, Ancona, Italy.
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy.
| | - Jacopo C DiFrancesco
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Department of Neurology, Epilepsy Center, ASST San Gerardo Hospital, University of Milano- Bicocca, Monza, Italy.
| | - Ilaria Rivolta
- School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy.
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