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Harris JR, Gao CW, Britton JF, Applegate CD, Bjornsson HT, Fahrner JA. Five years of experience in the Epigenetics and Chromatin Clinic: what have we learned and where do we go from here? Hum Genet 2024; 143:607-624. [PMID: 36952035 PMCID: PMC10034257 DOI: 10.1007/s00439-023-02537-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 02/20/2023] [Indexed: 03/24/2023]
Abstract
The multidisciplinary Epigenetics and Chromatin Clinic at Johns Hopkins provides comprehensive medical care for individuals with rare disorders that involve disrupted epigenetics. Initially centered on classical imprinting disorders, the focus shifted to the rapidly emerging group of genetic disorders resulting from pathogenic germline variants in epigenetic machinery genes. These are collectively called the Mendelian disorders of the epigenetic machinery (MDEMs), or more broadly, Chromatinopathies. In five years, 741 clinic visits have been completed for 432 individual patients, with 153 having confirmed epigenetic diagnoses. Of these, 115 individuals have one of 26 MDEMs with every single one exhibiting global developmental delay and/or intellectual disability. This supports prior observations that intellectual disability is the most common phenotypic feature of MDEMs. Additional common phenotypes in our clinic include growth abnormalities and neurodevelopmental issues, particularly hypotonia, attention-deficit/hyperactivity disorder (ADHD), and anxiety, with seizures and autism being less common. Overall, our patient population is representative of the broader group of MDEMs and includes mostly autosomal dominant disorders impacting writers more so than erasers, readers, and remodelers of chromatin marks. There is an increased representation of dual function components with a reader and an enzymatic domain. As expected, diagnoses were made mostly by sequencing but were aided in some cases by DNA methylation profiling. Our clinic has helped to facilitate the discovery of two new disorders, and our providers are actively developing and implementing novel therapeutic strategies for MDEMs. These data and our high follow-up rate of over 60% suggest that we are achieving our mission to diagnose, learn from, and provide optimal care for our patients with disrupted epigenetics.
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Affiliation(s)
- Jacqueline R Harris
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Kennedy Krieger Institute, Baltimore, MD, USA
| | - Christine W Gao
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Johns Hopkins Medical Scientist Training Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jacquelyn F Britton
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carolyn D Applegate
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hans T Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Landspitali University Hospital, Reykjavik, Iceland
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Abstract
Structural variation in genomes, such as copy number variants (CNVs), is under scrutiny for its contribution to phenotypic expression and evolution. Regions of homozygosity (ROH) are ripe for phenotype-gene discovery. Determining the genes and related phenotypes within genomic regions is key to studying potential functional and phenotypic consequences. Because individuals have multiple CNVs and ROHs in their genome, identifying genomic regions that are phenotypically significant is challenging. GeneScout is a web-based tool that can be used to search genomic regions to display and filter the genes and their associated phenotypes within regions of interest. Phenotypes and their associated gene(s) can then be filtered to show only the genes with phenotypes that have a particular inheritance pattern and/or specific clinical feature(s). Phenotypes can then be selected to compare the clinical synopses side-by-side in Online Mendelian Inheritance in Man (OMIM® ). Additionally, two coordinate sets can be compared to determine either the regions of overlap or the unique regions (subtraction). The resulting coordinate ranges are displayed on the results page, and the results table displays only the genes and phenotypes present within the coordinate ranges. The interactive table includes gene-specific links to external resources such as ClinVar, ClinGen validity, ClinGen dosage, and gnomAD, and a diamond symbol next to the gene name indicates a gene that spans the start or end of a coordinate range. Searches and comparisons may be performed for coordinates in assemblies GRCh37 (hg19) and GRCh38 (hg38). The results page offers the option to liftover coordinates entered in GRCh37 to GRCh38 and updates the results table to display the gene content based on assembly GRCh38. The search coordinates and results table can be downloaded in a tab-delimited or Excel file. © 2022 Wiley Periodicals LLC. Basic Protocol: Searching GeneScout.
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Affiliation(s)
- Carolyn D Applegate
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Ada Hamosh
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joanna S Amberger
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
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3
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Cif L, Demailly D, Lin JP, Barwick KE, Sa M, Abela L, Malhotra S, Chong WK, Steel D, Sanchis-Juan A, Ngoh A, Trump N, Meyer E, Vasques X, Rankin J, Allain MW, Applegate CD, Attaripour Isfahani S, Baleine J, Balint B, Bassetti JA, Baple EL, Bhatia KP, Blanchet C, Burglen L, Cambonie G, Seng EC, Bastaraud SC, Cyprien F, Coubes C, d'Hardemare V, Doja A, Dorison N, Doummar D, Dy-Hollins ME, Farrelly E, Fitzpatrick DR, Fearon C, Fieg EL, Fogel BL, Forman EB, Fox RG, Gahl WA, Galosi S, Gonzalez V, Graves TD, Gregory A, Hallett M, Hasegawa H, Hayflick SJ, Hamosh A, Hully M, Jansen S, Jeong SY, Krier JB, Krystal S, Kumar KR, Laurencin C, Lee H, Lesca G, François LL, Lynch T, Mahant N, Martinez-Agosto JA, Milesi C, Mills KA, Mondain M, Morales-Briceno H, Ostergaard JR, Pal S, Pallais JC, Pavillard F, Perrigault PF, Petersen AK, Polo G, Poulen G, Rinne T, Roujeau T, Rogers C, Roubertie A, Sahagian M, Schaefer E, Selim L, Selway R, Sharma N, Signer R, Soldatos AG, Stevenson DA, Stewart F, Tchan M, Verma IC, de Vries BBA, Wilson JL, Wong DA, Zaitoun R, Zhen D, Znaczko A, Dale RC, de Gusmão CM, Friedman J, Fung VSC, King MD, Mohammad SS, Rohena L, Waugh JL, Toro C, Raymond FL, Topf M, Coubes P, Gorman KM, Kurian MA. KMT2B-related disorders: expansion of the phenotypic spectrum and long-term efficacy of deep brain stimulation. Brain 2021; 143:3242-3261. [PMID: 33150406 DOI: 10.1093/brain/awaa304] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/28/2020] [Accepted: 07/13/2020] [Indexed: 12/31/2022] Open
Abstract
Heterozygous mutations in KMT2B are associated with an early-onset, progressive and often complex dystonia (DYT28). Key characteristics of typical disease include focal motor features at disease presentation, evolving through a caudocranial pattern into generalized dystonia, with prominent oromandibular, laryngeal and cervical involvement. Although KMT2B-related disease is emerging as one of the most common causes of early-onset genetic dystonia, much remains to be understood about the full spectrum of the disease. We describe a cohort of 53 patients with KMT2B mutations, with detailed delineation of their clinical phenotype and molecular genetic features. We report new disease presentations, including atypical patterns of dystonia evolution and a subgroup of patients with a non-dystonic neurodevelopmental phenotype. In addition to the previously reported systemic features, our study has identified co-morbidities, including the risk of status dystonicus, intrauterine growth retardation, and endocrinopathies. Analysis of this study cohort (n = 53) in tandem with published cases (n = 80) revealed that patients with chromosomal deletions and protein truncating variants had a significantly higher burden of systemic disease (with earlier onset of dystonia) than those with missense variants. Eighteen individuals had detailed longitudinal data available after insertion of deep brain stimulation for medically refractory dystonia. Median age at deep brain stimulation was 11.5 years (range: 4.5-37.0 years). Follow-up after deep brain stimulation ranged from 0.25 to 22 years. Significant improvement of motor function and disability (as assessed by the Burke Fahn Marsden's Dystonia Rating Scales, BFMDRS-M and BFMDRS-D) was evident at 6 months, 1 year and last follow-up (motor, P = 0.001, P = 0.004, and P = 0.012; disability, P = 0.009, P = 0.002 and P = 0.012). At 1 year post-deep brain stimulation, >50% of subjects showed BFMDRS-M and BFMDRS-D improvements of >30%. In the long-term deep brain stimulation cohort (deep brain stimulation inserted for >5 years, n = 8), improvement of >30% was maintained in 5/8 and 3/8 subjects for the BFMDRS-M and BFMDRS-D, respectively. The greatest BFMDRS-M improvements were observed for trunk (53.2%) and cervical (50.5%) dystonia, with less clinical impact on laryngeal dystonia. Improvements in gait dystonia decreased from 20.9% at 1 year to 16.2% at last assessment; no patient maintained a fully independent gait. Reduction of BFMDRS-D was maintained for swallowing (52.9%). Five patients developed mild parkinsonism following deep brain stimulation. KMT2B-related disease comprises an expanding continuum from infancy to adulthood, with early evidence of genotype-phenotype correlations. Except for laryngeal dysphonia, deep brain stimulation provides a significant improvement in quality of life and function with sustained clinical benefit depending on symptoms distribution.
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Affiliation(s)
- Laura Cif
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Diane Demailly
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Jean-Pierre Lin
- Complex Motor Disorder Service, Children's Neurosciences Department, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.,Children's Neuromodulation Group, Women and Children's Health Institute, Faculty of life Sciences and Medicine (FOLSM), King's Health Partners, London, UK
| | - Katy E Barwick
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Mario Sa
- Complex Motor Disorder Service, Children's Neurosciences Department, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Lucia Abela
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Sony Malhotra
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, UK
| | - Wui K Chong
- Developmental Imaging and Biophysics, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Dora Steel
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Alba Sanchis-Juan
- NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.,Department of Haematology, NHS Blood and Transplant Centre, University of Cambridge, Cambridge, UK
| | - Adeline Ngoh
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Natalie Trump
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Esther Meyer
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
| | | | - Julia Rankin
- Clinical Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Meredith W Allain
- Division of Medical Genetics, Department of Pediatrics, Stanford University, Palo Alto, CA, USA
| | - Carolyn D Applegate
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sanaz Attaripour Isfahani
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Julien Baleine
- Unité de Soins Intensifs et Réanimation Pédiatrique et Néonatale, Hôpital Universitaire de Montpellier, Montpellier, France
| | - Bettina Balint
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Jennifer A Bassetti
- Division of Medical Genetics, Department of Pediatrics, Weill Cornell Medical College, New York, NY, USA
| | - Emma L Baple
- Clinical Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK.,Institute of Biomedical and Clinical Science RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Catherine Blanchet
- Département d'Oto-Rhino-Laryngologie et Chirurgie Cervico-Faciale, Hôpital Universitaire de Montpellier, Montpellier, France
| | - Lydie Burglen
- Département de génétique médicale, APHP Hôpital Armand Trousseau, Paris, France
| | - Gilles Cambonie
- Unité de Soins Intensifs et Réanimation Pédiatrique et Néonatale, Hôpital Universitaire de Montpellier, Montpellier, France
| | - Emilie Chan Seng
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | | | - Fabienne Cyprien
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Christine Coubes
- Département de Génétique médicale, Maladies rares et médecine personnalisée, CHU Montpellier, Montpellier, France
| | - Vincent d'Hardemare
- Unité Dyspa, Neurochirurgie Pédiatrique, Hôpital Fondation Rothschild, Paris, France
| | | | - Asif Doja
- Division of Neurology, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Nathalie Dorison
- Unité Dyspa, Neurochirurgie Pédiatrique, Hôpital Fondation Rothschild, Paris, France
| | - Diane Doummar
- Neuropédiatrie, Centre de référence neurogénétique mouvement anormaux de l'enfant, Hôpital Armand Trousseau, AP-HP, Sorbonne Université, France
| | - Marisela E Dy-Hollins
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Ellyn Farrelly
- Division of Medical Genetics, Department of Pediatrics, Stanford University, Palo Alto, CA, USA.,Department of Pediatrics, Lucile Packard Children's Hospital at Stanford, CA, USA
| | - David R Fitzpatrick
- Human Genetics Unit, Medical and Developmental Genetics, University of Edinburgh Western General Hospital, Edinburgh, Scotland, UK
| | - Conor Fearon
- Department of Neurology, The Dublin Neurological Institute at the Mater Misericordiae University Hospital, Dublin, Ireland
| | - Elizabeth L Fieg
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brent L Fogel
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Eva B Forman
- Department of Paediatric Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Rachel G Fox
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | | | - William A Gahl
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Serena Galosi
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Victoria Gonzalez
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Tracey D Graves
- Department of Neurology, Hinchingbrooke Hospital, North West Anglia NHS Foundation Trust, Huntingdon, UK
| | - Allison Gregory
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Harutomo Hasegawa
- Complex Motor Disorder Service, Children's Neurosciences Department, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.,Children's Neuromodulation Group, Women and Children's Health Institute, Faculty of life Sciences and Medicine (FOLSM), King's Health Partners, London, UK
| | - Susan J Hayflick
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA.,Department of Paediatrics, Oregon Health and Science University, Portland, OR, USA
| | - Ada Hamosh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marie Hully
- Département de Neurologie, APHP-Necker-Enfants Malades, Paris, France
| | - Sandra Jansen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Suh Young Jeong
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Joel B Krier
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sidney Krystal
- Département de Neuroradiologie, Hôpital Fondation Rothschild, Paris
| | - Kishore R Kumar
- Translational Genomics Group, Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.,Department of Neurogenetics, Kolling Institute, University of Sydney and Royal North Shore Hospital, St Leonards, NSW, Australia.,Molecular Medicine Laboratory, Concord Hospital, Sydney, NSW, Australia
| | - Chloé Laurencin
- Département de Neurologie, Hôpital Neurologique Pierre Wertheimer, Lyon, France
| | - Hane Lee
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Gaetan Lesca
- Département de Génétique, Hôpital Universitaire de Lyon, Lyon, France
| | | | - Timothy Lynch
- Department of Neurology, The Dublin Neurological Institute at the Mater Misericordiae University Hospital, Dublin, Ireland.,UCD School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Neil Mahant
- Movement Disorders Unit, Department of Neurology, Westmead Hospital, Westmead, NSW, Australia
| | - Julian A Martinez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Christophe Milesi
- Unité de Soins Intensifs et Réanimation Pédiatrique et Néonatale, Hôpital Universitaire de Montpellier, Montpellier, France
| | - Kelly A Mills
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michel Mondain
- Département d'Oto-Rhino-Laryngologie et Chirurgie Cervico-Faciale, Hôpital Universitaire de Montpellier, Montpellier, France
| | - Hugo Morales-Briceno
- Movement Disorders Unit, Department of Neurology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | | | - John R Ostergaard
- Centre for Rare Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Swasti Pal
- Institute of Genetics and Genomics, Sir Ganga Ram Hospital, Rajender Nagar, New Delhi, India
| | - Juan C Pallais
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Frédérique Pavillard
- Département d'Anesthésie-Réanimation Gui de Chauliac, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | - Pierre-Francois Perrigault
- Département d'Anesthésie-Réanimation Gui de Chauliac, Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | | | - Gustavo Polo
- Département de Neurochirurgie Fonctionnelle, Hôpital Neurologique et Neurochirurgical, Pierre Wertheimer, Lyon, France
| | - Gaetan Poulen
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Tuula Rinne
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas Roujeau
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France
| | - Caleb Rogers
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Agathe Roubertie
- Département de Neuropédiatrie, Hôpital Universitaire de Montpellier, Montpellier, France.,INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Michelle Sahagian
- Division of Neurology, Rady Children's Hospital San Diego, CA, USA.,Department of Neuroscience, University of California San Diego, CA, USA
| | - Elise Schaefer
- Medical Genetics, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Laila Selim
- Cairo University Children Hospital, Pediatric Neurology and Metabolic division, Cairo, Egypt
| | - Richard Selway
- Department of Neurosurgery, King's College Hospital, London, UK
| | - Nutan Sharma
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA.,Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA
| | - Rebecca Signer
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ariane G Soldatos
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - David A Stevenson
- Division of Medical Genetics, Department of Pediatrics, Stanford University, Palo Alto, CA, USA
| | - Fiona Stewart
- Department of Genetic Medicine, Belfast Health and Social Care Trust, Belfast, UK
| | - Michel Tchan
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Department of Genetics, Westmead Hospital, Westmead, NSW, Australia
| | | | - Ishwar C Verma
- Institute of Genetics and Genomics, Sir Ganga Ram Hospital, Rajender Nagar, New Delhi, India
| | - Bert B A de Vries
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny L Wilson
- Division of Pediatric Neurology, Department of Pediatrics, Oregon Health and Science University, Portland, OR, USA
| | - Derek A Wong
- Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Raghda Zaitoun
- Department of Paediatrics, Neurology Division, Ain Shams University Hospital, Cairo, Egypt
| | - Dolly Zhen
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Anna Znaczko
- Department of Genetic Medicine, Belfast Health and Social Care Trust, Belfast, UK
| | - Russell C Dale
- Department of Paediatric Neurology, The Children's Hospital at Westmead, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney NSW, Australia
| | - Claudio M de Gusmão
- Department of Neurology, Harvard Medical School, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Jennifer Friedman
- Division of Neurology, Rady Children's Hospital San Diego, CA, USA.,Department of Neuroscience, University of California San Diego, CA, USA.,Departments of Paediatrics, University of California, San Diego, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Victor S C Fung
- Movement Disorders Unit, Department of Neurology, Westmead Hospital, Westmead, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Mary D King
- Department of Paediatric Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,UCD School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Shekeeb S Mohammad
- Department of Paediatric Neurology, The Children's Hospital at Westmead, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney NSW, Australia
| | - Luis Rohena
- Division of Medical Genetics, Department of Pediatrics, San Antonio Military Medical Center, San Antonio, TX, USA.,Department of Pediatrics, Long School of Medicine, UT Health, San Antonio, TX, USA
| | - Jeff L Waugh
- Division of Pediatric Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, USA
| | - Camilo Toro
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - F Lucy Raymond
- NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Maya Topf
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, University of London, London, UK
| | - Philippe Coubes
- Département de Neurochirurgie, Unité des Pathologies Cérébrales Résistantes, Unité de Recherche sur les Comportements et Mouvements Anormaux, Hôpital Gui de Chauliac, Centre Hospitalier Régional Montpellier, Montpellier, France.,Faculté de médecine, Université de Montpellier, France
| | - Kathleen M Gorman
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
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Luperchio TR, Applegate CD, Bodamer O, Bjornsson HT. Haploinsufficiency of KMT2D is sufficient to cause Kabuki syndrome and is compatible with life. Mol Genet Genomic Med 2019; 8:e1072. [PMID: 31814321 PMCID: PMC7005614 DOI: 10.1002/mgg3.1072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Teresa Romeo Luperchio
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carolyn D Applegate
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Olaf Bodamer
- Division of Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard University, Cambridge, MA, USA
| | - Hans Tomas Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.,Landspitali University Hospital, Reykjavik, Iceland
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5
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Fichtman B, Harel T, Biran N, Zagairy F, Applegate CD, Salzberg Y, Gilboa T, Salah S, Shaag A, Simanovsky N, Ayoubieh H, Sobreira N, Punzi G, Pierri CL, Hamosh A, Elpeleg O, Harel A, Edvardson S. Pathogenic Variants in NUP214 Cause "Plugged" Nuclear Pore Channels and Acute Febrile Encephalopathy. Am J Hum Genet 2019; 105:48-64. [PMID: 31178128 DOI: 10.1016/j.ajhg.2019.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 05/06/2019] [Indexed: 12/15/2022] Open
Abstract
We report biallelic missense and frameshift pathogenic variants in the gene encoding human nucleoporin NUP214 causing acute febrile encephalopathy. Clinical symptoms include neurodevelopmental regression, seizures, myoclonic jerks, progressive microcephaly, and cerebellar atrophy. NUP214 and NUP88 protein levels were reduced in primary skin fibroblasts derived from affected individuals, while the total number and density of nuclear pore complexes remained normal. Nuclear transport assays exhibited defects in the classical protein import and mRNA export pathways in affected cells. Direct surface imaging of fibroblast nuclei by scanning electron microscopy revealed a large increase in the presence of central particles (known as "plugs") in the nuclear pore channels of affected cells. This observation suggests that large transport cargoes may be delayed in passage through the nuclear pore channel, affecting its selective barrier function. Exposure of fibroblasts from affected individuals to heat shock resulted in a marked delay in their stress response, followed by a surge in apoptotic cell death. This suggests a mechanistic link between decreased cell survival in cell culture and severe fever-induced brain damage in affected individuals. Our study provides evidence by direct imaging at the single nuclear pore level of functional changes linked to a human disease.
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Affiliation(s)
- Boris Fichtman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Tamar Harel
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Nitzan Biran
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Fadia Zagairy
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Carolyn D Applegate
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Yuval Salzberg
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Tal Gilboa
- Pediatric Neurology Unit, Hadassah-Hebrew University Medical Center, Jerusalem 91240, Israel
| | - Somaya Salah
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Avraham Shaag
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Natalia Simanovsky
- Department of Medical Imaging, Hadassah Medical Center, Jerusalem 91240, Israel
| | - Houriya Ayoubieh
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Nara Sobreira
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Giuseppe Punzi
- Laboratory of Biochemistry, Molecular and Computational Biology; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Ciro Leonardo Pierri
- Laboratory of Biochemistry, Molecular and Computational Biology; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Ada Hamosh
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Orly Elpeleg
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Amnon Harel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel.
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah-Hebrew University Medical Center, Jerusalem 91240, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
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6
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Wagner CL, Hanumanthu VS, Talbot CC, Abraham RS, Hamm D, Gable DL, Kanakry CG, Applegate CD, Siliciano J, Jackson JB, Desiderio S, Alder JK, Luznik L, Armanios M. Short telomere syndromes cause a primary T cell immunodeficiency. J Clin Invest 2018; 128:5222-5234. [PMID: 30179220 DOI: 10.1172/jci120216] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 08/28/2018] [Indexed: 12/13/2022] Open
Abstract
The mechanisms that drive T cell aging are not understood. We report that children and adult telomerase mutation carriers with short telomere length (TL) develop a T cell immunodeficiency that can manifest in the absence of bone marrow failure and causes life-threatening opportunistic infections. Mutation carriers shared T cell-aging phenotypes seen in adults 5 decades older, including depleted naive T cells, increased apoptosis, and restricted T cell repertoire. T cell receptor excision circles (TRECs) were also undetectable or low, suggesting that newborn screening may identify individuals with germline telomere maintenance defects. Telomerase-null mice with short TL showed defects throughout T cell development, including increased apoptosis of stimulated thymocytes, their intrathymic precursors, in addition to depleted hematopoietic reserves. When we examined the transcriptional programs of T cells from telomerase mutation carriers, we found they diverged from older adults with normal TL. Short telomere T cells upregulated DNA damage and intrinsic apoptosis pathways, while older adult T cells upregulated extrinsic apoptosis pathways and programmed cell death 1 (PD-1) expression. T cells from mice with short TL also showed an active DNA-damage response, in contrast with old WT mice, despite their shared propensity to apoptosis. Our data suggest there are TL-dependent and TL-independent mechanisms that differentially contribute to distinct molecular programs of T cell apoptosis with aging.
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Affiliation(s)
| | | | - C Conover Talbot
- Institute for Basic Biomedical Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Roshini S Abraham
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - David Hamm
- Adaptive Biotechnologies, Seattle, Washington, USA
| | | | | | | | | | | | - Stephen Desiderio
- Institute for Basic Biomedical Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Sidney Kimmel Comprehensive Cancer Center, and.,Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Leo Luznik
- Department of Oncology and.,Sidney Kimmel Comprehensive Cancer Center, and
| | - Mary Armanios
- Department of Oncology and.,McKusick-Nathans Institute of Genetic Medicine.,Department of Pathology.,Sidney Kimmel Comprehensive Cancer Center, and.,Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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7
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Berrios C, James CA, Raraigh K, Bollinger J, Murray B, Tichnell C, Applegate CD, Bergner AL. Enrolling Genomics Research Participants through a Clinical Setting: the Impact of Existing Clinical Relationships on Informed Consent and Expectations for Return of Research Results. J Genet Couns 2018; 27:263-273. [PMID: 28932961 PMCID: PMC7539290 DOI: 10.1007/s10897-017-0143-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 08/09/2017] [Indexed: 11/29/2022]
Abstract
Genetic counselors working in a clinical setting may find themselves recruiting, enrolling, and returning results for genomic research, and existing clinical relationships with study participants may impact these research interactions. We present a qualitative study using semi-structured interviews of participants enrolled in a genome sequencing/exome sequencing (GS/ES) study at the same institution where they receive clinical care. Interviews were coded for motivations to participate and expectations of this research. The interviews revealed common motivations for participation, including altruism and hope for benefit for themselves, family members, and/or others with their condition. Additionally, themes emerged related to unintentional influence based on trust of the clinical provider that recruited them to the study. Participant trust in the enrolling provider at times appeared to extend to the study team to decide which research results to return and to do so in an appropriate format. Participants also based expectations for research results return on previous clinical genetic testing experiences, which may or may not be realistic depending on study design. It is imperative that genetic counselors enrolling patients into research studies be aware of the potential influence of their clinical relationship on potential subjects, be transparent about their role on the study team, and help set expectations about the study process, including results return.
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Affiliation(s)
- Courtney Berrios
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, 600 North Wolfe Street, Blalock 1008, Baltimore, MD, 21287, USA
| | - Cynthia A James
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Karen Raraigh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, 600 North Wolfe Street, Blalock 1008, Baltimore, MD, 21287, USA
| | - Juli Bollinger
- Berman Institute of Bioethics, Johns Hopkins University, Baltimore, MD, USA
| | - Brittney Murray
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Crystal Tichnell
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Carolyn D Applegate
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, 600 North Wolfe Street, Blalock 1008, Baltimore, MD, 21287, USA
| | - Amanda L Bergner
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, 600 North Wolfe Street, Blalock 1008, Baltimore, MD, 21287, USA.
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8
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Stanley SE, Gable DL, Wagner CL, Carlile TM, Hanumanthu VS, Podlevsky JD, Khalil SE, DeZern AE, Rojas-Duran MF, Applegate CD, Alder JK, Parry EM, Gilbert WV, Armanios M. Loss-of-function mutations in the RNA biogenesis factor NAF1 predispose to pulmonary fibrosis-emphysema. Sci Transl Med 2017; 8:351ra107. [PMID: 27510903 DOI: 10.1126/scitranslmed.aaf7837] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 07/14/2016] [Indexed: 12/23/2022]
Abstract
Chronic obstructive pulmonary disease and pulmonary fibrosis have been hypothesized to represent premature aging phenotypes. At times, they cluster in families, but the genetic basis is not understood. We identified rare, frameshift mutations in the gene for nuclear assembly factor 1, NAF1, a box H/ACA RNA biogenesis factor, in pulmonary fibrosis-emphysema patients. The mutations segregated with short telomere length, low telomerase RNA levels, and extrapulmonary manifestations including myelodysplastic syndrome and liver disease. A truncated NAF1 was detected in cells derived from patients, and, in cells in which the frameshift mutation was introduced by genome editing, telomerase RNA levels were reduced. The mutant NAF1 lacked a conserved carboxyl-terminal motif, which we show is required for nuclear localization. To understand the disease mechanism, we used CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein-9 nuclease) to generate Naf1(+/-) mice and found that they had half the levels of telomerase RNA. Other box H/ACA RNA levels were also decreased, but rRNA pseudouridylation, which is guided by snoRNAs, was intact. Moreover, first-generation Naf1(+/-) mice showed no evidence of ribosomal pathology. Our data indicate that disease in NAF1 mutation carriers is telomere-mediated; they show that NAF1 haploinsufficiency selectively disturbs telomere length homeostasis by decreasing the levels of telomerase RNA while sparing rRNA pseudouridylation.
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Affiliation(s)
- Susan E Stanley
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Medical Scientist Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dustin L Gable
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Medical Scientist Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Christa L Wagner
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Thomas M Carlile
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Vidya Sagar Hanumanthu
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Joshua D Podlevsky
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85277, USA
| | - Sara E Khalil
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Amy E DeZern
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Maria F Rojas-Duran
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Carolyn D Applegate
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jonathan K Alder
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Erin M Parry
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Wendy V Gilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mary Armanios
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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9
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Pilarowski GO, Vernon HJ, Applegate CD, Boukas L, Cho MT, Gurnett CA, Benke PJ, Beaver E, Heeley JM, Medne L, Krantz ID, Azage M, Niyazov D, Henderson LB, Wentzensen IM, Baskin B, Sacoto MJG, Bowman GD, Bjornsson HT. Missense variants in the chromatin remodeler CHD1 are associated with neurodevelopmental disability. J Med Genet 2017; 55:561-566. [PMID: 28866611 DOI: 10.1136/jmedgenet-2017-104759] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/07/2017] [Accepted: 08/04/2017] [Indexed: 11/04/2022]
Abstract
BACKGROUND The list of Mendelian disorders of the epigenetic machinery has expanded rapidly during the last 5 years. A few missense variants in the chromatin remodeler CHD1 have been found in several large-scale sequencing efforts focused on uncovering the genetic aetiology of autism. OBJECTIVES To explore whether variants in CHD1 are associated with a human phenotype. METHODS We used GeneMatcher to identify other physicians caring for patients with variants in CHD1. We also explored the epigenetic consequences of one of these variants in cultured fibroblasts. RESULTS Here we describe six CHD1 heterozygous missense variants in a cohort of patients with autism, speech apraxia, developmental delay and facial dysmorphic features. Importantly, three of these variants occurred de novo. We also report on a subject with a de novo deletion covering a large fraction of the CHD1 gene without any obvious neurological phenotype. Finally, we demonstrate increased levels of the closed chromatin modification H3K27me3 in fibroblasts from a subject carrying a de novo variant in CHD1. CONCLUSIONS Our results suggest that variants in CHD1 can lead to diverse phenotypic outcomes; however, the neurodevelopmental phenotype appears to be limited to patients with missense variants, which is compatible with a dominant negative mechanism of disease.
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Affiliation(s)
- Genay O Pilarowski
- Predoctoral Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hilary J Vernon
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Department of Pediatrics, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA
| | - Carolyn D Applegate
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Leandros Boukas
- Predoctoral Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Christina A Gurnett
- Department of Neurology, Division of Pediatric Neurology, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Paul J Benke
- Joe DiMaggio Children's Hospital, Florida Atlantic School of Medicine, Hollywood, Florida, USA
| | - Erin Beaver
- Mercy Kids Genetics, Mercy Hospital, Saint Louis, Missouri, USA
| | | | - Livija Medne
- Division of Human Genetics, Department of Pediatrics, Individualized Medical Genetics Center, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Ian D Krantz
- Division of Human Genetics, Department of Pediatrics, Individualized Medical Genetics Center, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Meron Azage
- Department of Pediatrics, Ochsner Clinic, New Orleans, Louisiana, USA
| | - Dmitriy Niyazov
- Department of Pediatrics, Ochsner Clinic, New Orleans, Louisiana, USA
| | | | | | | | | | - Gregory D Bowman
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hans T Bjornsson
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Pediatrics, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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10
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Affiliation(s)
- Yulia Wolfson
- Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland
| | - Carolyn D Applegate
- Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Rupert W Strauss
- Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland3Department of Ophthalmology, Medical University Graz, Graz, Austria
| | - Ian C Han
- Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland
| | - Hendrik P Scholl
- Department of Ophthalmology, Johns Hopkins University, Baltimore, Maryland
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11
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Lemmon ME, Lavenstein B, Applegate CD, Hamosh A, Tekes A, Singer HS. A novel presentation of DYT 16: Acute onset in infancy and association with MRI abnormalities. Mov Disord 2013; 28:1937-8. [DOI: 10.1002/mds.25703] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/02/2013] [Accepted: 09/11/2013] [Indexed: 11/11/2022] Open
Affiliation(s)
- Monica E. Lemmon
- Department of Neurology; The Johns Hopkins Hospital, Johns Hopkins University School of Medicine; Baltimore MD
| | - Bennett Lavenstein
- Department of Neurology; Children's National Medical Center, George Washington University; District of Columbia
| | - Carolyn D. Applegate
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins Hospital, Johns Hopkins University School of Medicine; Baltimore MD
| | - Ada Hamosh
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins Hospital, Johns Hopkins University School of Medicine; Baltimore MD
| | - Aylin Tekes
- The Russell H. Morgan Department of Radiology and Radiological Sciences; The Johns Hopkins Hospital, Johns Hopkins University School of Medicine; Baltimore MD
| | - Harvey S. Singer
- Department of Neurology; The Johns Hopkins Hospital, Johns Hopkins University School of Medicine; Baltimore MD
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12
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Fahrner JA, Frazier A, Bachir S, Walsh MF, Applegate CD, Thompson R, Halushka MK, Murphy AM, Gunay-Aygun M. A rasopathy phenotype with severe congenital hypertrophic obstructive cardiomyopathy associated with a PTPN11 mutation and a novel variant in SOS1. Am J Med Genet A 2012; 158A:1414-21. [PMID: 22585553 DOI: 10.1002/ajmg.a.35363] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 03/03/2012] [Indexed: 01/26/2023]
Abstract
The RAS-MAPK pathway is critical for human growth and development. Abnormalities at different steps of this signaling cascade result in neuro-cardio-facial-cutaneous syndromes, or the RASopathies, a group of disorders with overlapping yet distinct phenotypes. RASopathy patients have variable degrees of intellectual disability, poor growth, relative macrocephaly, ectodermal abnormalities, dysmorphic features, and increased risk for certain malignancies. Congenital heart disease, particularly hypertrophic cardiomyopathy (HCM) and pulmonic stenosis, are prominent features in these disorders. Significant locus heterogeneity exists for many of the RASopathies. Traditionally, these diseases were thought to be inherited in an autosomal dominant manner. However, recently patients with defects in two components of this pathway and overlapping features of various forms of Noonan syndrome and neurofibromatosis 1 and have been reported. Here we present a patient with severe, progressive neonatal HCM, elevated urinary catecholamine metabolites, and dysmorphic features in whom we identified a known LEOPARD syndrome-associated PTPN11 mutation (c.1403 C > T; p.T468M) and a novel, potentially pathogenic missense SOS1 variant (c.1018 C > T; p.P340S) replacing a rigid nonpolar imino acid with a polar amino acid at a highly conserved position. We describe detailed clinical manifestations, cardiac histopathology, and the molecular genetic findings. Oligogenic models of inheritance with potential synergistic effects should be considered in the RASopathies.
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Affiliation(s)
- Jill A Fahrner
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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13
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Mhyre TR, Applegate CD. Persistent regional increases in brain-derived neurotrophic factor in the flurothyl model of epileptogenesis are dependent upon the kindling status of the animal. Neuroscience 2004; 121:1031-45. [PMID: 14580953 DOI: 10.1016/s0306-4522(03)00475-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) appears to be both regulated by and a regulator of epileptogenesis. In the flurothyl (HFE) model of kindling mice exposed to successive flurothyl trials over 8 days express a rapid, long-lasting reduction in generalized seizure threshold and a more slowly evolving change in seizure phenotype in response to subsequent flurothyl exposure. The BDNF genotype of particular mouse strains appears to influence the epileptogenic progression in this model. Thus, we hypothesized that BDNF signaling pathways are altered by flurothyl-induced seizures. Following HFE kindling, fully kindled (eight seizures) adult male C57BI/6J mice had significantly elevated whole brain BDNF levels through at least 28 days after their final seizure. Mice that received only four HFE seizures (not kindled) had elevated BDNF levels, but only at 1 day post-seizure (DPSz), while BDNF levels were not significantly altered in mice receiving just one HFE seizure at any time point studied. Regional expression patterns of BDNF in the hippocampus, hypothalamus, and frontal cortex were also elevated by one DPSz and returned to control values by 14 DPSz in mice that received four HFE seizures. No changes were seen in the cerebellum, striatum, or piriform cortex. In contrast, fully kindled mice had significantly elevated BDNF levels within the hippocampus, hypothalamus, neocortex, and striatum that remained elevated through at least 14 DPSz, while levels were unchanged in the cerebellum and piriform cortex. Regional results were confirmed using anti-BDNF immunohistochemistry (IHC). Despite changes in BDNF levels following HFE kindling, we were unable to demonstrate alterations either in full-length tyrosine kinase receptor B (TrkB) expression (Western blot and IHC) or in truncated TrkB (IHC) expression levels. Together, these data suggest a model of a positive feedback loop involving seizure activity and seizure number and persistently modified BDNF signaling pathways that influences seizure phenotypes within the HFE kindling paradigm. Thus, long-term elevations in BDNF may be responsible in part for epileptogenic processes and the development of human refractory epilepsies.
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Affiliation(s)
- T R Mhyre
- Strong Epilepsy Center, Department of Neurology, University of Rochester Medical Center, Box 673, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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14
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Ferland RJ, Gross RA, Applegate CD. Increased mitotic activity in the dentate gyrus of the hippocampus of adult C57BL/6J mice exposed to the flurothyl kindling model of epileptogenesis. Neuroscience 2003; 115:669-83. [PMID: 12435406 DOI: 10.1016/s0306-4522(02)00514-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Repeated flurothyl-induced generalized forebrain seizures result in a progressive and permanent lowering of the generalized seizure threshold in mice and an increase in the percentage of animals expressing forebrain-brainstem seizures, when rechallenged with flurothyl, after a stimulation-free period. Since this seizure paradigm serves as an excellent model for examining changes in seizure threshold and seizure propagation, we were interested in examining mitotic activity in hippocampal progenitors following flurothyl-induced epileptogenesis. In the present studies, we investigated (1). the effect of one or eight flurothyl-induced seizures on mitotic activity in the hippocampal dentate gyrus of adult mice measured by 5-bromo-2'-deoxyuridine incorporation, (2). the time course of change in hippocampal mitotic activity, (3). the cellular phenotype of these mitotically active cells, and (4). the relationship of changes in mitotic activity to changes in seizure threshold and phenotype. Significant increases in hippocampal mitotic activity were observed in mice exposed to either one or eight flurothyl-induced seizures. Increases were observed at 1 and 3 days following one seizure, and at 0, 1, 3, and 7 days following eight seizures. Confocal analyses, using neuronal and glial markers, suggest that the majority of these mitotic cells are neurons. In addition, no correlation was observed between hippocampal mitotic activity and the final seizure type that animals expressed following incubation and flurothyl retest. A significant correlation was observed between hippocampal mitotic activity and seizure threshold in flurothyl-kindled mice. Overall, these results indicate that both one and eight flurothyl-induced seizures are potent inducers of hippocampal neurogenesis in adult mice. Results further suggest that the increases in hippocampal neurogenesis are not directly related to the processes that underlie the shift in behavioral seizure phenotype, but may be involved in either the establishment or the maintenance of seizure threshold in this flurothyl model of epileptogenesis.
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Affiliation(s)
- R J Ferland
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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15
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Abstract
PURPOSE This study sought to determine whether there was a transfer of seizure susceptibility between two models of epileptogenesis, electrical kindling and a newly described model of flurothyl kindling. In this study, we determined the effects of preexposure to one kindling agent on the seizure responsiveness to the other. METHODS Mice were divided into three groups: (a) six mice (FLK) were kindled with flurothyl, rechallenged with flurothyl after a 28-day incubation phase, implanted with olfactory bulb (OB) electrodes, and electrically kindled; (b) six mice (ELK) were implanted with OB electrodes, electrically kindled to six stage 5 seizures, and given one flurothyl trial 3 days later and a second flurothyl trial after a 28-day incubation period; and (c) six mice (IMP) were implanted with OB electrodes, tested with flurothyl at the same times as the ELK group, and later electrically kindled. RESULTS Mice that were previously kindled with flurothyl (FLK) had significantly faster electrical kindling rates to one stage 5 seizure or to six stage 5 seizures compared with animals in the ELK and IMP groups. Mice that were previously exposed to either electrical kindling or flurothyl kindling had significantly diminished latencies to generalized seizure onset (flurothyl-induced seizure thresholds) either before or after a 28-day incubation period compared with the IMP control mice. In addition, both the FLK and ELK groups had significantly increased percentages of mice expressing forebrain-brainstem seizures, compared with the IMP group, following either rechallenge with flurothyl after a 28-day incubation or focal electrical kindling. CONCLUSIONS These findings indicate a near-complete bidirectional transfer between these electrical and flurothyl kindling models. Mice that were previously exposed to either electrical or flurothyl kindling have increased seizure susceptibilities and altered seizure phenotypes when exposed to the other seizure paradigm. Overall, these studies indicate that previous seizures are the critical determinant of the bidirectional transfer of seizure susceptibility observed, and not the electrical or pharmacologic properties of the original kindling agent. Finally, the observation of near identity in transfer characteristics between electrical and flurothyl kindling models suggests that the proepileptogenic processes initiated by exposure to either model are similar.
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Affiliation(s)
- R J Ferland
- Department of Neurology, University of Rochester School of Medicine and Dentistry, New York, USA
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16
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Abstract
Previous studies have shown that mice bearing a targeted disruption of the 5-HT2C receptor gene exhibit an epilepsy syndrome associated with sporadic spontaneous seizures that occasionally result in death. In this study, we have defined the seizure susceptibility profiles of these 5-HT2C receptor mutant mice backcrossed onto a C57BL/6 background. Wild-type and mutant animals were either electrically kindled from the olfactory bulb, exposed to corneal electroshock, or tested with the chemoconvulsant, flurothyl. In all paradigms, mice lacking the 5-HT2C receptor were significantly more seizure susceptible than wild-type controls. Results indicate that mutants have lower focal seizure thresholds, increased focal seizure excitability, and facilitated propagation within the forebrain seizure system. Mutants also exhibit lower generalized seizure thresholds for the expression of both generalized clonic and generalized tonic seizures. Importantly, the 5-HT receptor antagonist, mesulergine (2 or 4 mg/kg), administered prior to electroshock testing, recapitulated the mutant phenotype in wild-type mice. Together, these data strongly implicate a role for serotonin and 5-HT2C receptors in the modulation of neuronal network excitability and seizure propagation globally, throughout the CNS.
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MESH Headings
- Animals
- Behavior, Animal/physiology
- Brain Chemistry/drug effects
- Brain Chemistry/physiology
- Convulsants/pharmacology
- Cornea
- Disease Susceptibility
- Dopamine Agonists/pharmacology
- Electroshock
- Epilepsies, Myoclonic/chemically induced
- Epilepsies, Myoclonic/genetics
- Epilepsy/chemically induced
- Epilepsy/genetics
- Ergolines/pharmacology
- Flurothyl/pharmacology
- Kindling, Neurologic/drug effects
- Kindling, Neurologic/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Receptor, Serotonin, 5-HT2C
- Receptors, Serotonin/genetics
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Affiliation(s)
- C D Applegate
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, USA.
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17
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Abstract
Flurothyl kindling initiates a time-dependent process that results in a facilitated propagation from the forebrain to the brainstem seizure system and in an increase in the complexity of behavioral seizure expression. We investigated the involvement of the ventromedial nucleus of the hypothalamus (VMH) in mediating this facilitated propagation between these seizure systems. Bilateral ibotenic acid lesions of the VMH, but not the dorsomedial nucleus of the hypothalamus (DMH), resulted in a disruption in the propagation of seizure activity from the forebrain to the brainstem. Moreover, VMH lesioned mice were able to express brainstem seizures following minimal corneal electroconvulsive shock (mECS). Together, our results indicate that the VMH is a critical substrate involved in propagating seizure activity between the forebrain and brainstem, but is not involved in the expression systems necessary for forebrain or brainstem seizure manifestations.
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Affiliation(s)
- R J Ferland
- Program in Neuroscience, The Strong Epilepsy Center, University of Rochester School of Medicine and Dentistry, NY 14642, USA
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18
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Abstract
We have recently demonstrated that eight, daily flurothyl-induced generalized clonic seizures, followed by a four week stimulus-free interval, results in a long-lasting reduction in generalized seizure threshold and a change in the type of seizure expressed in response to flurothyl from clonic to tonic. There is a progressive increase in the probability that a mouse will express a tonic seizure during the four week interval, suggesting that prior flurothyl seizures initiate a proepileptogenic process that requires time to develop. In this study, the immunohistochemical detection of the c-fos protein (Fos) was used to evaluate whether seizure-induced epileptogenesis resulted in regional differences in the degree of neuronal activation. Fos immunoreactivity was examined 1.5 h following either a single generalized seizure, the last of eight consecutive daily seizures or a retest seizure evoked two weeks after the last of eight seizures. In each condition, generalized seizure behaviours were elicited in C57BL/6 mice using flurothyl and classified as either "forebrain" (face and forelimb clonus) or "brainstem" (running/bouncing, treading, tonic extension). The spatial distribution of Fos induction was compared on the basis of the seizure phenotype and the seizure history. The predominant differences in Fos distribution were found to be related to the type of seizure expressed regardless of the seizure history. Furthermore, the different motor components that make up a "brainstem" seizure could not be distinguished by the pattern of Fos labelling suggesting that multiple convulsive behaviours are mediated by one anatomical system. Finally, Fos induction in the ventromedial hypothalamic nucleus preceded and predicted the change in seizure type from "forebrain" to "brainstem". These data support the concept that separate anatomical systems mediate the expression of the two generalized seizure phenotypes. In addition, the ventromedial nucleus of the hypothalamus may be a point of interaction between the systems and may play a role in seizure-induced neural reorganization.
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Affiliation(s)
- G M Samoriski
- Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, NY 14642, USA
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19
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Abstract
The perirhinal cortex (PRh) has been suggested as a substrate for the expression of generalized clonic seizures in the late stages of kindling development (stages 4-5). Using the induction of Fos as a marker of neuronal activation, the PRh region was investigated after kindling or nonkindling electrical stimulation. Nonkindling electrical stimulation of the PRh elicited stimulus-locked behaviors, without afterdischarge. These behaviors were characterized by rearing and bilateral forelimb clonus which were terminated upon electrical stimulus offset in half of the rats displaying this behavior (with the other half expressing self-sustained seizures). In these animals, Fos immunoreactivity was found throughout neocortical and subcortical structures in the hemisphere ipsilateral to the stimulating electrode. By contrast, Fos-immunoreactivity in the contralateral hemisphere was localized primarily in the PRh and frontal motor cortex. Likewise, similar patterns of Fos immunoreactivity were observed in both hemispheres of rats following kindling to one generalized clonic seizure from several limbic and paleocortical structures. These results suggest that the bilateral involvement of the PRh is critical in producing the bilateral behaviors associated with generalized clonic seizure expression. In support of this interpretation, infusion of 3 M KCl directly into the contralateral PRh of rats kindled to a single stage 4-5 (generalized clonic) seizure from the ipsilateral amygdala reduced seizure manifestations from a generalized clonic seizure (stage 4-5) to a unilateral clonic seizure (stage 3) without affecting measures of focal excitability. Taken together, these data indicate a role for the bilateral involvement of the PRh in generalized clonic seizure expression whether evoked from the naive or kindled state. These results further indicate that bilateral behaviors require the bilateral involvement of the structures necessary for the expression of these behaviors.
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Affiliation(s)
- R J Ferland
- Comprehensive Epilepsy Program, Program in Neuroscience
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20
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Ferland RJ, Applegate CD. Decreased brainstem seizure thresholds and facilitated seizure propagation in mice exposed to repeated flurothyl-induced generalized forebrain seizures. Epilepsy Res 1998; 30:49-62. [PMID: 9551844 DOI: 10.1016/s0920-1211(97)00093-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We recently have described a novel model of epileptogenesis utilizing the inhalant chemoconvulsant, flurothyl (Applegate et al., 1997; Samoriski and Applegate, 1997). The hallmark feature of this model is a change in behavioral seizure phenotype from a forebrain seizure, observed during the initial flurothyl exposures, to a brainstem seizure, elicited by flurothyl, after a 28-day stimulation free incubation period. In this study, we sought to establish the basis for this change in behavioral seizure response. To this end, we examined the effects of exposure to this paradigm on the generalized brainstem seizure threshold and on the propagation of forebrain seizures onto the brainstem seizure substrate. Ten mice were given flurothyl-induced generalized forebrain seizures on 8 consecutive days (induction phase). The other ten mice were not exposed to the flurothyl induction paradigm and served as controls. Minimal corneal electroconvulsive shock (mECS--20 mA) was used to assay whether there was any change in the animals' generalized brainstem seizure thresholds at 3, 14 and 28 days following the last flurothyl seizure trial. Mice that were exposed to flurothyl exhibited a progressive increase in the percentage of animals having a mECS-induced brainstem seizure when tested at 3 (40%), 14 (70%) and 28 (90%) days following the last flurothyl seizure. Control mice rarely had a brainstem seizure at any of the three time points tested, mostly forebrain seizures were observed. These results suggest that there is a significant progressive lowering of the brainstem seizure threshold, during the incubation phase of the flurothyl paradigm, which is coincident with the previously reported time course of change in the behavioral seizure phenotype observed using this flurothyl model (Applegate et al., 1997; Samoriski and Applegate, 1997). Following mECS testing, mice were implanted with bipolar electrodes and kindled from the olfactory bulb (OB). Mice exposed to the flurothyl paradigm demonstrated significantly faster kindling rates, longer afterdischarge durations. and longer durations of and latencies to stage 5 seizures compared to controls. Furthermore, animals exposed to the flurothyl protocol demonstrated an increase in the expression of brainstem seizures after focally-elicited OB afterdischarges. These results suggest that there is an increased interaction between the forebrain and brainstem seizure systems after exposure to this model of epileptogenesis. Together, results indicate that the change in behavioral seizure phenotype observed following exposure to our flurothyl paradigm are promoted by both decreases in brainstem seizure thresholds and facilitated forebrain seizure propagation onto the brainstem seizure system.
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Affiliation(s)
- R J Ferland
- Department of Neurology, University of Rochester School of Medicine and Dentistry, NY 14642, USA
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21
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Samoriski GM, Applegate CD. Repeated generalized seizures induce time-dependent changes in the behavioral seizure response independent of continued seizure induction. J Neurosci 1997; 17:5581-90. [PMID: 9204939 PMCID: PMC6793817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
This study examined both the acute and long-lasting changes in seizure susceptibility that occur in response to the repeated induction of generalized seizure activity. Daily flurothyl-induced generalized clonic seizures resulted in a progressive decrease in both the generalized seizure threshold and the latency to the first myoclonic jerk. The threshold reduction was significant as early as the second trial and was maximal by trial 5. However, a minimum of eight seizures was necessary for the maximal reduction to be long-lasting. The present study also examined the effects of the number of seizures and the duration of the stimulation-free interval on the type of generalized seizure expressed. During the induction phase of the experiment, only generalized clonic seizures ("forebrain seizures") were expressed. If, however, the animal was retested after a 1, 2, 3, or 4 week stimulation-free interval, a progressive increase in both the proportion of animals expressing "brainstem seizure" behaviors and the median seizure score was observed. The progression of flurothyl-induced generalized seizure behaviors was significantly altered if (1) a minimum of eight generalized clonic seizures had been expressed, and (2) a minimum of a 2 week stimulation-free interval followed. Fewer generalized clonic seizures failed to reliably produce changes in seizure phenotype, even after extended stimulus-free intervals. These data indicate that specific kindling processes are initiated during the interval of repeated seizure induction and evolve in the absence of continued seizure induction. Furthermore, these mechanisms of epileptogenesis were found to be manifest predominantly as a change in the seizure phenotype expressed and to proceed independent of changes in the generalized seizure threshold.
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Affiliation(s)
- G M Samoriski
- Program in Neuroscience and The Comprehensive Epilepsy Program, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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22
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Abstract
PURPOSE We have developed and characterized a novel model of epileptogenesis based on the convulsive actions of flurothyl in mice. The hallmark feature of this model is a reliable change in the type of seizure expressed in response to flurothyl from generalized clonic to generalized tonic seizures. The purpose of our study was to evaluate the effects of chronic administration of valproate (VPA), phenytoin (PHT), and MK-801 on the change in seizure phenotype observed in our model system. METHODS Male C57BL/6J mice received flurothyl seizures on 8 consecutive days. Two hours after the last generalized seizure, chronic drug or vehicle was administered twice daily at 12-h intervals for 28 days. The drugs evaluated were VPA (250 mg/kg), PHT (30 mg/kg), and MK-801 (0.5 mg/kg). After a 7-day drug washout period, mice were retested with flurothyl. RESULTS Among uninjected or vehicle-injected control mice, there was a significant increase in the proportion of animals expressing tonic seizures after the 28-day stimulation-free interval. Chronic administration of VPA or MK-801, but not PHT, blocked the characteristic change in seizure type from clonic to tonic. CONCLUSIONS The change in seizure phenotype observed after exposure to our paradigm indicates a fundamental reorganization in the propagation of flurothyl-initiated seizures. As in electrical kindling, VPA and MK-801 are effective at blocking or retarding the reorganization, whereas PHT is not. The concordance in pharmacologic profiles between kindling and our model suggests that the processes underlying changes in seizure susceptibility in these two models share mechanisms in common.
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MESH Headings
- Animals
- Anticonvulsants/pharmacology
- Behavior, Animal/drug effects
- Brain Stem/drug effects
- Disease Models, Animal
- Dizocilpine Maleate/pharmacology
- Dose-Response Relationship, Drug
- Epilepsy/chemically induced
- Epilepsy/classification
- Epilepsy/prevention & control
- Epilepsy, Generalized/chemically induced
- Epilepsy, Generalized/prevention & control
- Epilepsy, Tonic-Clonic/chemically induced
- Epilepsy, Tonic-Clonic/prevention & control
- Flurothyl/pharmacology
- Kindling, Neurologic/drug effects
- Kindling, Neurologic/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Motor Activity/drug effects
- Neural Pathways/drug effects
- Phenytoin/pharmacology
- Valproic Acid/pharmacology
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Affiliation(s)
- C D Applegate
- Comprehensive Epilepsy Program and Program in Neuroscience, University of Rochester School of Medicine and Dentistry, New York, USA
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23
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Abstract
The study was designed to determine which type of cell death occurs following kindling induced seizures, and to determine which neurons die. For this purpose seizures were kindled from the entorhinal cortex. Following a range of 5-85 stage 5 seizures, rats were sacrificed, and the tissue was prepared for analysis. The TUNEL and silver impregnation methods were used to identify apoptotic or necrotic cell death, respectively. These methods were subsequently combined with immunocytochemistry, to determine if diseased neurons expressed somatostatin or the NMDA receptor (NMDAR1). The tissue analysis demonstrated that following kindling induced seizures, 1) hippocampal and extrahippocampal neurons die, 2) some neurons die through apoptosis, others through necrosis, and 3) some of the diseased neurons express somatostatin, others the NMDAR1 and that both subpopulations of neurons are present at hippocampal and extrahippocampal sites.
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Affiliation(s)
- S Pretel
- Department of Neurobiology and Anatomy, School of Medicine and Dentistry, Rochester, N.Y. 14641, USA
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24
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Abstract
The expression of generalized clonic and generalized tonic seizures has been suggested to result from the activation of different and independent neuronal circuits. Using the induction of the c-fos protein (Fos) as a marker of neuronal activity, we identified brain structures that are differentially associated with the expression of electroconvulsive shock-induced generalized clonic and generalized tonic seizures. Expression of either seizure phenotype resulted in a similar bilaterally symmetrical increase in Fos immunoreactivity in many forebrain structures, including the bed nucleus of the stria terminalis, hippocampal dentate gyrus, amygdala, and piriform cortex, compared to controls. However, following tonic hindlimb extension (THE), the degree of labeling in specific thalamic, hypothalamic, and brain stem areas was significantly greater than that of either controls or animals exhibiting clonic seizures. While a greater number of neurons in the hypothalamus (e.g., ventromedial nucleus), subparafascicular thalamic nucleus, peripeduncular area, deep medial superior colliculus, dorsal and lateral central gray, and paralemniscal nuclei were robustly labeled following THE, noticeably fewer cells were immunoreactive following face and forelimb clonic seizure behaviors. These differences were also found to be independent of the stimulus magnitude. In animals stimulated with the same current intensity but expressing either of the two seizure phenotypes, the pattern of Fos induction was consistent with the seizure phenotype expressed. These results demonstrate that specific subsets of neurons are differentially activated following the expression of different generalized seizure behaviors and that activity in discrete mesencephalic and diencephalic structures is more frequently associated with the expression of generalized tonic seizures than with the expression of generalized clonic seizures.
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Affiliation(s)
- G M Samoriski
- Program in Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, USA
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25
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Abstract
Due to the complex nature of generalized limbic seizures, marked disturbances in physiological homeostasis occur. Accompanying the motor manifestations which characteristically are associated with generalized limbic seizures, alterations in neuroendocrine, behavioral, and autonomic functions may be observed. The paraventricular nucleus (PVN) of the hypothalamus is known to play a significant role in such neuronal responses to stressful stimuli; however, the effect of seizures on hypothalamic neurons is unknown. We have used the immunocytochemical detection of the Fos protein to anatomically identify neurons in the PVN which are activated following generalized limbic seizures. To induce seizures, rats received intraperitoneal injections of kainic acid or were kindled from the entorhinal cortex. We have demonstrated that elicitation of generalized limbic seizures induces a dramatic number of neurons in the PVN to express the Fos protein. Numerous Fos-immunolabeled neurons were identified in both the parvicellular and magnocellular component of the PVN. In the latter, this study clearly reveals a preferential and selective activation of oxytocin-containing neurons, and it extends and supports the hypothesis that oxytocin plays a role in the body's response to specific stress paradigms. Data suggest that an activation of the oxytocin neuronal system may be part of the adaptive mechanism that enables the hypothalamus to modulate and maintain an adequate response to stressors (e.g., generalized seizures) to regain homeostasis.
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Affiliation(s)
- D T Piekut
- Department of Neurobiology and Anatomy, University of Rochester School of Medicine, New York 14642, USA
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26
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Abstract
PURPOSE Our previous research indicated that the exposure of rat pups to an hypoxic environment during a discrete developmental period (postnatal days 10-15) produces short-term seizures and confers an enduring increase in susceptibility to pentylenetetrazol- and flurothyl-induced seizures. In this study, we evaluated the effects of hypoxic insult in this neonatal period of susceptibility to electrical kindling and corneal electroconvulsive shock. METHODS Ten-day-old rat pups were exposed to a 3% O2 environment, as previously described, and were either kindled or exposed to corneal electroshock at adulthood (70 days old). RESULTS Neither kindled seizure development from the septal nucleus or amygdala nor electroconvulsive shock profiles were significantly altered by hypoxic pretreatment. CONCLUSIONS Results indicate that hypoxia produces increases in seizure susceptibility that are observable in only some experimental seizure models but not in others. This outcome serves to target some anatomic systems more than others in the mechanisms involved in hypoxia-induced neural reorganization.
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Affiliation(s)
- C D Applegate
- Comprehensive Epilepsy Program, University of Rochester School of Medicine and Dentistry, New York, USA
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27
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Abstract
In this study, the regulation of hypothalamic oxytocin and vasopressin messenger RNA expression following the induction of seizures was investigated by in situ hybridization. Following kainic acid-induced seizures, a significant increase in oxytocin messenger RNA in the paraventricular nucleus was demonstrated at 1.5 h, one and two weeks; its level decreased at three weeks and was significantly increased again at four weeks; at eight weeks the messenger RNA level still remained higher than that of controls. Vasopressin messenger RNA in the paraventricular nucleus was increased significantly only at 1.5 h following induction of seizures. The oxytocin messenger RNA level in the supraoptic nucleus was also increased early at 1.5 h and later at four weeks following seizures; however, these increases did not last as long as those in the paraventricular nucleus. Vasopressin messenger RNA in the supraoptic nucleus was also increased after the initial seizures; however, its messenger RNA level vacillated up and down throughout the post-seizure times studied. The earliest significant increase of vasopressin messenger RNA was at one week after seizures, and there was a late significant increase of vasopressin messenger RNA at three weeks after seizures. The present study demonstrates that following kainic acid-induced seizures both, the oxytocin and vasopressin messenger RNA expressions, were up-regulated and these up-regulations were long-term events. The increase of oxytocin messenger RNA in the paraventricular nucleus was more persistent than the others. The pattern of messenger RNA up-regulation was different for oxytocin and vasopressin, and different in the paraventricular nucleus and supraoptic nucleus. These different patterns of messenger RNA elevations suggest that the different components of the rat hypothalamus were regulated differentially by kainic acid-induced seizures.
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Affiliation(s)
- Q Sun
- Department of Neurobiology and Anatomy, University of Rochester, NY 14642, USA
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28
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Abstract
The present study demonstrates the anatomical extent of the kindling-activated neuronal network in general, and specifically the recruitment of extrahippocampal somatostatin (SST)-synthesizing neurons into this network. It has been known that SST neurons of the hippocampal formation are activated during episodes of seizure, however, it was not known if this activation was a local event or extended to other areas in the brain. We were therefore interested in determining if and which SST neurons outside the hippocampal formation might be recruited into this seizure-activated neuronal network. Using the kindling model of seizure elicitation, expression of the Fos protein in activated, depolarized neurons was utilized to identify seizure-activated neurons. Subsequently, the mRNA for SST was identified through in situ hybridization in the same tissue section, allowing the identification of seizure-activated, SST-synthesizing neurons. The results show that: (a) the majority of SST-synthesizing neurons in the forebrain and diencephalon became activated during the kindling development; (b) their recruitment into the kindling-activated neuronal network occurred progressively; and, (c) these SST-synthesizing neurons represented a component of the kindling-activated neuronal network throughout the development of kindling-induced seizures.
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Affiliation(s)
- S Pretel
- Department of Neurobiology and Anatomy, University of Rochester, School of Medicine and Dentistry, NY 14642, USA
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29
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Abstract
The extent of the neuronal network that is activated by kainic acid-induced seizures was anatomically identified and neurochemically characterized. Seizure-activated neurons were identified through the immunocytochemical demonstration of Fos protein in neuronal nuclei. These seizure-activated neurons were characterized by determining if they contained the mRNA for somatostatin or enkephalin, using in situ hybridization procedures. The results demonstrate that a majority of enkephalin- and somatostatin-synthesizing neurons expressed the Fos protein following seizures and that they represent a major component of the kainic acid-induced, seizure-activated neuronal network.
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Affiliation(s)
- S Pretel
- Department of Neurobiology and Anatomy, University of Rochester, School of Medicine and Dentistry, NY 14642, USA
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30
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Abstract
The induction of the proto-oncogene c-fos has been used extensively to identify spatially distributed neural systems activated by seizures. The substantia nigra pars reticulata (SNpr) has been implicated as a critical structure in neural networks involved in the modulation of seizure expression, yet the SNpr has not been reported to express Fos following seizures induced in a variety of seizure paradigms. In this study we determined whether (1) the temporal characteristics of Fos induction in the SNpr were different than those of other brain areas following kindled seizures, (2) neurons in the SNpr possess the cellular machinery to express Fos, (3) Fos can be induced in SNpr by direct electrical stimulation, and (4) Fos expression is induced in the SNpr following kainate or pilocarpine-induced status epilepticus. Results indicate that Fos is not induced in SNpr at any time point (1-12 h) after kindled seizures, and that serum response factor, a constitutively expressed nuclear protein necessary for Fos expression, is present in SNpr neurons. Results further indicate that Fos expression in the SNpr is induced following either direct electrical stimulation or pilocarpine status, but not status elicited by kainate. We conclude that, in so far as the SNpr represents a critical structure for modulating seizure expression, seizure activity does not represent a sufficient stimulus to induce Fos in SNpr neurons. Further, the neural networks defined by Fos expression following seizure may be incomplete, and should be interpreted conservatively.
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Affiliation(s)
- C D Applegate
- Department of Neurology, University of Rochester School of Medicine and Dentistry, NY 14642
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31
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Abstract
The present study was designed to determine if and to what extent somatostatin (SST) synthesizing neurons of the hippocampal formation are activated during seizures, elicited through kindling of the perforant pathway. Tissue was used and analyzed from animals which had experienced a single after discharge, or a stage 3 or stage 5 seizure. The protein expression of the oncogene c-fos in activated, depolarizing neurons was utilized to identify seizure-activated SST-synthesizing neurons. Combined immunocytochemical and in situ hybridization methods were used to identify these double-labeled, Fos protein, and SST mRNA-containing neurons. The results were quantified and compared across seizure stages. The resulting data demonstrate that at every stage of seizure development, a majority of SST-synthesizing neurons is activated, but that these activated SST mRNA-containing neurons represent only a minority of all seizure-activated, Fos-expressing neurons in the hippocampal formation. The data further reveal a numerical hierarchy in which the majority of double-labeled neurons is present in the hilus of the dentate, followed by the stratum oriens of CA1. It is concluded that SST-synthesizing neurons represent an integral component of the kindling activated neuronal network and, since the SST synthesizing neurons represent the minority of all seizure-activated neurons in the hippocampal formation, that this neuronal network is likely to be of considerable neurochemical complexity.
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Affiliation(s)
- S Pretel
- Department of Neurobiology, School of Medicine and Dentistry, University of Rochester, New York 14642, USA
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32
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Abstract
Amygdala kindling resulted in significant increases in the expression of D2 receptor mRNA in the nucleus accumbens and striatum 30 days following the last kindling stimulation. Densitometric analyses of tissue sections incubated in the presence of an oligonucleotide probe directed against D2 receptor cDNA indicated a 20-35% increase in D2 receptor mRNA in these regions following kindling. Kindling from the amygdala followed by piriform cortical kindling in the transfer paradigm (overkindling) resulted in significant further increases in D2 receptor mRNA expression in both the accumbens (150% increase) and striatum (120% increase). There were no observed hemispheric asymmetries in D2 receptor mRNA in either kindled or overkindled animals. The data indicate an enduring upregulation of extrapyramidal D2 receptor mRNA following the kindling process. How this change may relate to kindling-induced alterations in seizure susceptibility or behaviors mediated by limbic dopaminergic pathways are questions for future studies.
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Affiliation(s)
- H A Gelbard
- Department of Neurology, University of Rochester Medical Center, NY 14642
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33
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Abstract
Investigations into the neurochemical or molecular biological mechanisms underlying the kindled state require a seizure induction procedure for eliciting generalized tonic-clonic seizures in naive animals. Such seizure controls are necessary for dissociating the influence of ictal motor events on measures of interest from the influence of the kindling process on these same measures. In this study three procedures for inducing seizures in naive animals were evaluated against a set of criteria considered ideal.
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Affiliation(s)
- C D Applegate
- Department of Neurology, University of Rochester School of Medicine and Dentistry, NY 14642
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34
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Applegate CD, Samoriski GM, Burchfiel JL. Evidence for the interaction of brainstem systems mediating seizure expression in kindling and electroconvulsive shock seizure models. Epilepsy Res 1991; 10:142-7. [PMID: 1817954 DOI: 10.1016/0920-1211(91)90006-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Amygdala kindling was observed to increase significantly the proportion of rats that exhibited tonic hindlimb extension in response to corneal electroshock stimulation. Mechanical brainstem lesions which abolished electroshock-induced tonic hindlimb extension failed to alter either the expression of fully generalized kindled seizures or the development of amygdala kindled seizures. Results suggest that while kindling can alter the sensitivity of brainstem systems involved in the expression of tonic hindlimb extension, these same systems are not necessary for either the development or expression of amygdala kindled seizures.
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Affiliation(s)
- C D Applegate
- Comprehensive Epilepsy Program, University of Rochester School of Medicine and Dentistry, NY 14642
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35
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Abstract
The response to cerebral hypoxia/ischemia may be different in the neonate compared to other age groups. An in vivo model was developed in the rat to determine whether there are age-dependent differences in the effects of hypoxia on electroencephalographic (EEG) activity. EEG recordings were obtained from Long Evans hooded rats deprived of oxygen at five ages: postnatal days 5 to 7, 10 to 12, 15 to 17, 25 to 27, and 50 to 60. Oxygen concentration was varied from 0, 2, 3, and 4% between animals. EEGs were recorded in all animals before, during, and at 1 hour after exposure to the hypoxic condition and at 1 to 7 days afterward in a subset of animals. All animals were deprived of oxygen until the onset of apnea and bradycardia to 20 to 40% of baseline heart rate values. Hypoxia resulted in isoelectric EEG significantly more frequently in the animals deprived of oxygen at postnatal days 25 to 27 and 50 to 60 than in the younger age groups. A highly significant effect was that the animals deprived at postnatal days 5 to 17 revealed a high incidence of epileptiform EEG activity during hypoxia. In contrast, the older animals exhibited only rare isolated EEG spikes before reaching an isoelectric EEG. The severity of hypoxia-induced epileptiform EEG changes was highest in the animals subjected to moderately hypoxic conditions (3% and 4% oxygen) at postnatal days 10 to 12. Furthermore, epileptiform changes persisted for hours to days following prolonged episodes of hypoxia in the younger animals. This study demonstrates a unique response of the immature brain to exhibit epileptiform activity during hypoxia.
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Affiliation(s)
- F E Jensen
- Department of Neurology, Children's Hospital, Boston, MA 02115
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36
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DeLeo JA, Applegate CD, Burchfiel JL, Lorenzo AV, Hsi DH. Perinatal exposure to anoxia alone does not alter the susceptibility to amygdaloid-kindled seizures in the adult rabbit. Brain Res 1990; 522:168-71. [PMID: 2224513 DOI: 10.1016/0006-8993(90)91596-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It is suggested that asphyxia on newborns increases the susceptibility to epileptic syndromes. The effect of perinatal and postnatal anoxia on subsequent seizure susceptibility was assessed by amygdaloid kindling in adult rabbits. Rabbits from 1 day pre-term to 53 days were exposed to 100% N2 for an average of 7 min or until the heart rate was reduced by 70%. Non-anoxic littermates served as controls. At 2 months of age, animals were implanted with bilateral amygdalae electrodes. After a postsurgical recovery period, afterdischarge (AD) thresholds were determined for the electrode sites and a kindling paradigm was performed. There were no significant differences in the rate of kindling in all groups studied (control, anoxic at 1 day pre-term or at term, anoxic at 44 and 53 days). These results demonstrate that perinatal anoxia did not alter the seizure susceptibility in the adult rabbit kindling model.
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Affiliation(s)
- J A DeLeo
- Dartmouth Medical School, Anesthesia Research Laboratory, Hanover, NH 03756
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37
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Abstract
Kindling antagonism' is a modification of the standard kindling paradigm in which two limbic system structures are stimulated on alternate trials. The consistent outcome of this procedure is that one site ('dominant site') develops typical generalized seizures, while kindled seizure development from the other site ('suppressed site') is arrested at an intermediate stage. Our recent research suggests that kindling antagonism is dependent on hindbrain norepinephrine (NE) systems. The present study explores this relationship further. Neonatal rats were treated with intracerebral injections of 6-hydroxydopamine (6-OHDA). At adulthood, these animals received either (1) a low dose of 6-OHDA (75 micrograms), (2) a high dose of 6-OHDA (200 micrograms), or (3) vehicle. Regional NE concentrations were determined by high pressure liquid chromatography. Neonatal 6-OHDA followed by vehicle resulted in decreases in forebrain and increases in hindbrain NE concentrations. Low dose 6-OHDA at adulthood depleted cerebellar, but not pontine-medullary NE. High dose 6-OHDA resulted in depletions of both cerebellar and pontine-medullary NE. Only high dose 6-OHDA significantly interfered with the development of antagonism. Neonatal 6-OHDA facilitated the rate of dominant site kindling independently of subsequent adult treatment regimens. Results suggest that the influence of NE on kindling antagonism is mediated through a brain-stem substrate and that the influence of NE on kindling rate is mediated through a forebrain substrate.
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Affiliation(s)
- C D Applegate
- Department of Neurology, University of Rochester, NY 14642
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38
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Abstract
The effects of intraamygdala injections of either gamma-vinyl GABA or muscimol on the behavioral and electrographic expression of stable, fully generalized, kindled seizures were assessed. Results suggest that intraamygdala administration of GABA agonists preferentially attenuates the behavioral, but not the focal, electrographic expression of kindled seizures elicited from either the insular or entorhinal cortex. These results, in conjunction with those of others, suggest that the amygdala becomes an integral and necessary structure for the expression of seizures kindled from a variety of forebrain areas.
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Affiliation(s)
- C D Applegate
- Laboratory of Developmental Neurophysiology, Children's Hospital, Boston, Massachusetts
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Waszczak BL, Applegate CD, Burchfiel JL. Kindling does not cause persistent changes in firing rates or transmitter sensitivities of substantia nigra pars reticulata neurons. Brain Res 1988; 455:115-22. [PMID: 2901283 DOI: 10.1016/0006-8993(88)90120-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
These studies were undertaken to determine whether the kindling process induces persistent alterations in the functional status of neurons of the substantia nigra pars reticulata, a brain area identified previously as a site important in regulating the expression of generalized motor seizures. Extracellular, single-unit recordings of pars reticulata neurons were made in chloral hydrate-anesthetized, fully kindled rats (2-3 weeks after the last seizure), or unkindled control rats of the same age and weight. Kindling caused no alterations in several electrophysiological parameters examined. For instance, neither the number of active pars reticulata cells encountered, nor their firing rates, were significantly different between kindled and control groups. In addition, kindling failed to alter the sensitivities of pars reticulata neurons to iontophoretic application of two inhibitory transmitters, gamma-aminobutyric acid and glycine, and two transmitters that excite these cells, glutamate and acetylcholine. These results suggest that while kindling produces enduring increases in seizure susceptibility, it causes no persistent interictal changes in either basal activity or several measures of transmitter sensitivity of substantia nigra pars reticulata neurons.
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Affiliation(s)
- B L Waszczak
- Pharmacology Section, Northeastern University College of Pharmacy and Allied Health Professions, Boston, MA
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40
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Applegate CD, Konkol RJ, Burchfiel JL. Kindling antagonism: a role for hindbrain norepinephrine in the development of site suppression following concurrent, alternate stimulation. Brain Res 1987; 407:212-22. [PMID: 3105818 DOI: 10.1016/0006-8993(87)91099-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The concurrent, alternate electrical stimulation of the septal nucleus and the entorhinal cortex results in the development of fully generalized seizures at one site (dominant site) and the lack of development of kindled seizures at the other (suppressed or antagonized site). We have labeled this phenomenon kindling antagonism. Previous work from our laboratory has demonstrated that the whole brain depletion of norepinephrine (NE) eliminates the development of kindling antagonism. In the present study animals were treated with the neurotoxin 6-hydroxydopamine (6-OHDA) as neonates. The neonatal administration of 6-OHDA produced robust increases in brainstem and cerebellar NE levels and depletions of forebrain NE levels when assayed at maturity. Striatal dopamine levels were spared by this treatment. Neonatal 6-OHDA did not alter the development of the kindling antagonism phenomenon which is typically observed following concurrent, alternate stimulation of the septal nucleus and entorhinal cortex. Neonatal 6-OHDA treatment significantly facilitated the rate of kindled seizure development at dominant sites but failed to alter thresholds for the elicitation of afterdischarges (AD) or patterns of development of AD durations. Other characteristics of kindling antagonism were similarly unaffected by 6-OHDA treatment. These data suggest that brainstem and/or cerebellar NE are sufficient to mediate the development of kindling antagonism in the relative absence of forebrain NE.
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Kuczenski R, Segal DS, Leith NJ, Applegate CD. Effects of amphetamine, methylphenidate, and apomorphine on regional brain serotonin and 5-hydroxyindole acetic acid. Psychopharmacology (Berl) 1987; 93:329-35. [PMID: 2448842 DOI: 10.1007/bf00187252] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Electrophysiological and cytofluorometric data suggest that doses of amphetamine which enhance locomotor activity and promote focused stereotypies produce pronounced effects on serotonin pathways in the CNS. However, the biochemical evidence regarding changes in serotonergic function produced by moderate doses of this drug is inconsistent. Therefore, the present study was designed to further examine the effects of amphetamine (1-5 mg/kg) on regional brain serotonin and its metabolite and to compare these effects to behaviorally comparable doses of methylphenidate and apomorphine. At doses which produce a multiphasic behavioral response pattern, including a stereotypy phase consisting primarily of repetitive head movements and occasional oral stereotypies, amphetamine (3 mg/kg) and methylphenidate (30 mg/kg) increased levels of 5HIAA in striatum and frontal cortex, two brain regions which receive serotonergic projections from the dorsal raphe nucleus. In contrast, these drugs decreased or had no effect on 5HIAA levels in hippocampus, a brain region which receives its serotonergic innervation from the median raphe nucleus. A moderate dose of apomorphine (0.5 mg/kg) produced a comparable pattern of neurochemical effects. These data are consistent with electrophysiological and cytofluorometric data suggesting enhanced dorsal raphe serotonergic function following amphetamine-like stimulants. Pretreatment of animals with alpha-methyltyrosine at a dose sufficient to prevent the locomotor stimulation and stereotypy promoted by amphetamine, or by haloperidol, failed to prevent the amphetamine-induced increase in 5HIAA, indicating that these serotonergic effects are not secondary to the amphetamine facilitation of dopaminergic transmission.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Kuczenski
- Department of Psychiatry, University of California, San Diego, La Jolla 92093
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42
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Abstract
Chronic pretreatment of rats with desmethylimipramine (DMI) significantly slowed the rate of seizure generalization elicited by repeated electrical stimulation of the entorhinal cortex (kindling). An identical drug regimen administered to either fully kindled rats or rats partially kindled to early motor seizure stages failed to significantly alter kindling profiles in these animals. Under these latter conditions, in fact, there was a tendency for chronic DMI to exacerbate seizure activity. The effect of chronic DMI pretreatment to slow the development of kindled seizure generalization did not occur if a two-week delay was interposed between the end of drug treatment and the beginning of kindling trials. Results suggest that the retardation of entorhinal cortical kindling rate is dependent on DMI-induced CNS adaptations which recover within two weeks following treatment, and this effect is dependent on the presence of DMI-induced adaptations in a naive (unkindled) nervous system. Alterations of either the kindled state or the adaptational state produced by chronic drug eliminate the slowing of seizure generalization observed when both conditions are present.
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Applegate CD, Burchfiel JL, Konkol RJ. Kindling antagonism: effects of norepinephrine depletion on kindled seizure suppression after concurrent, alternate stimulation in rats. Exp Neurol 1986; 94:379-90. [PMID: 3095132 DOI: 10.1016/0014-4886(86)90111-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The concurrent, alternate electrical stimulation of the entorhinal cortex and septal nucleus results in the development of fully generalized seizures at one electrode site and the suppression of seizure development at the other. We have labeled this phenomenon kindling antagonism. Selective, whole-brain depletion of norepinephrine (NE) virtually eliminates the development of kindling antagonism such that fully generalized seizures develop at both sites in a majority of animals. This effect occurs in the absence of appreciable changes in kindling characteristics of these animals compared with either untreated or vehicle-treated controls. These results suggest that the suppression of seizure development observed in the kindling antagonism model is normally maintained by a NE-dependent mechanism. Our results support those of earlier studies using single-site kindling paradigms in which NE depletion facilitates the rate of kindled seizure development. We suggest that the NE-dependent mechanism responsible for the seizure suppression observed to follow concurrent, alternate stimulation and the suppression of seizure development using single-site kindling paradigms may be the same. The nature of this NE-dependent seizure suppression mechanism and the anatomic locus or loci critical for this effect remain questions for future research.
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44
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Abstract
Low level stimulation of the amygdala central nucleus was found to produce bradycardia responses in awake rabbits. Within the central nucleus the most sensitive sites were located within the medial component. The bradycardia response was accompanied by changes in respiration, most commonly an increase in frequency and a decrease in tidal volume, as well as by pupillodilation. Somatomotor responses to central nucleus stimulation were an arrest of ongoing behavior and movements of the mouth and tongue. The pattern of responses observed following stimulation of this nucleus is similar to that observed in response to threatening stimuli and suggests a contribution for this nucleus in the integration of a species-appropriate emotional response in the rabbits.
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45
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Abstract
The dose-dependent decrease in striatal dopamine (DA) metabolites following apomorphine (APO) administration was utilized as an index of changes in DA receptor sensitivity following the repeated administration of amphetamine (AMPH). The results suggest that: (a) repeated AMPH pretreatment does not alter DA autoreceptor sensitivity; and (b) interpretations of the decline in striatal DA metabolites at high doses of APO (greater than 50 micrograms/kg), in terms of activation of postsynaptic DA receptors, may require re-evaluation.
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46
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Janowsky A, Okada F, Manier DH, Applegate CD, Sulser F, Steranka LR. Role of serotonergic input in the regulation of the beta-adrenergic receptor-coupled adenylate cyclase system. Science 1982; 218:900-1. [PMID: 6291152 DOI: 10.1126/science.6291152] [Citation(s) in RCA: 157] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The action of desipramine on the norepinephrine-sensitive adenylate cyclase system and the density of beta-adrenergic receptors in rat cortex was studied after selective lesioning of serotonergic neurons with 5,7-dihydroxytryptamine. In animals with lesions desipramine failed to reduce the density of beta-adrenoceptors but decreased the response of adenosine 3',5'-monophosphate to isoproterenol and norepinephrine to the same degree as in animals without lesions. The results demonstrate a functional linkage between serotonergic and noradrenergic systems in the rat cortex, with beta-adrenergic receptors and neurohormonal sensitivity of the adenosine 3',5'-monophosphate-generating system being under separate regulatory control.
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47
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Applegate CD, Frysinger RC, Kapp BS, Gallagher M. Multiple unit activity recorded from amygdala central nucleus during Pavlovian heart rate conditioning in rabbit. Brain Res 1982; 238:457-62. [PMID: 7093668 DOI: 10.1016/0006-8993(82)90123-8] [Citation(s) in RCA: 106] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Using a Pavlovian heart rate conditioning paradigm, a rapid development of short latency increases in the multiple unit activity of the amygdala central nucleus were observed in response to a tone conditioned stimulus. In some cases the increase in multiple unit response showed a parallel development with the conditioned decelerative heart rate response and were significantly correlated with it. These results suggest a direct role for the central nucleus in the expression of conditioned heart rate responding in rabbit.
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48
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Applegate CD. 5,7-dihydroxytryptamine-induced mouse killing and behavioral reversal with ventricular administration of serotonin in rats. Behav Neural Biol 1980; 30:178-90. [PMID: 7192550 DOI: 10.1016/s0163-1047(80)91053-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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