1
|
Fu JM, Satterstrom FK, Peng M, Brand H, Collins RL, Dong S, Wamsley B, Klei L, Wang L, Hao SP, Stevens CR, Cusick C, Babadi M, Banks E, Collins B, Dodge S, Gabriel SB, Gauthier L, Lee SK, Liang L, Ljungdahl A, Mahjani B, Sloofman L, Smirnov AN, Barbosa M, Betancur C, Brusco A, Chung BHY, Cook EH, Cuccaro ML, Domenici E, Ferrero GB, Gargus JJ, Herman GE, Hertz-Picciotto I, Maciel P, Manoach DS, Passos-Bueno MR, Persico AM, Renieri A, Sutcliffe JS, Tassone F, Trabetti E, Campos G, Cardaropoli S, Carli D, Chan MCY, Fallerini C, Giorgio E, Girardi AC, Hansen-Kiss E, Lee SL, Lintas C, Ludena Y, Nguyen R, Pavinato L, Pericak-Vance M, Pessah IN, Schmidt RJ, Smith M, Costa CIS, Trajkova S, Wang JYT, Yu MHC, Cutler DJ, De Rubeis S, Buxbaum JD, Daly MJ, Devlin B, Roeder K, Sanders SJ, Talkowski ME. Rare coding variation provides insight into the genetic architecture and phenotypic context of autism. Nat Genet 2022; 54:1320-1331. [PMID: 35982160 PMCID: PMC9653013 DOI: 10.1038/s41588-022-01104-0] [Citation(s) in RCA: 137] [Impact Index Per Article: 68.5] [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: 12/07/2021] [Accepted: 05/24/2022] [Indexed: 01/11/2023]
Abstract
Some individuals with autism spectrum disorder (ASD) carry functional mutations rarely observed in the general population. We explored the genes disrupted by these variants from joint analysis of protein-truncating variants (PTVs), missense variants and copy number variants (CNVs) in a cohort of 63,237 individuals. We discovered 72 genes associated with ASD at false discovery rate (FDR) ≤ 0.001 (185 at FDR ≤ 0.05). De novo PTVs, damaging missense variants and CNVs represented 57.5%, 21.1% and 8.44% of association evidence, while CNVs conferred greatest relative risk. Meta-analysis with cohorts ascertained for developmental delay (DD) (n = 91,605) yielded 373 genes associated with ASD/DD at FDR ≤ 0.001 (664 at FDR ≤ 0.05), some of which differed in relative frequency of mutation between ASD and DD cohorts. The DD-associated genes were enriched in transcriptomes of progenitor and immature neuronal cells, whereas genes showing stronger evidence in ASD were more enriched in maturing neurons and overlapped with schizophrenia-associated genes, emphasizing that these neuropsychiatric disorders may share common pathways to risk.
Collapse
Affiliation(s)
- Jack M Fu
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - F Kyle Satterstrom
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Minshi Peng
- Department of Statistics and Data Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Harrison Brand
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Surgical Research Laboratories, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA
| | - Ryan L Collins
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Bioinformatics and Integrative Genomics, Harvard Medical School, Boston, MA, USA
| | - Shan Dong
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Brie Wamsley
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Lambertus Klei
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Lily Wang
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Program in Bioinformatics and Integrative Genomics, Harvard Medical School, Boston, MA, USA
| | - Stephanie P Hao
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Pediatric Surgical Research Laboratories, Department of Surgery, Massachusetts General Hospital, Boston, MA, USA
| | - Christine R Stevens
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Caroline Cusick
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Mehrtash Babadi
- Data Sciences Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Eric Banks
- Data Sciences Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Brett Collins
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sheila Dodge
- Genomics Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Stacey B Gabriel
- Genomics Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Laura Gauthier
- Data Sciences Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Samuel K Lee
- Data Sciences Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Lindsay Liang
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Alicia Ljungdahl
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Behrang Mahjani
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Laura Sloofman
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Andrey N Smirnov
- Data Sciences Platform, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Mafalda Barbosa
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Catalina Betancur
- Sorbonne Université, INSERM, CNRS, Neuroscience Paris Seine, Institut de Biologie Paris Seine, Paris, France
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Turin, Italy
- Medical Genetics Unit, 'Città della Salute e della Scienza' University Hospital, Turin, Italy
| | - Brian H Y Chung
- Department of Pediatrics and Adolescent Medicine, Duchess of Kent Children's Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Edwin H Cook
- Institute for Juvenile Research, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - Michael L Cuccaro
- The John P Hussman Institute for Human Genomics, The University of Miami Miller School of Medicine, Miami, FL, USA
| | - Enrico Domenici
- Department of Cellular, Computational and Integrative Biology, , University of Trento, Trento, Italy
| | | | - J Jay Gargus
- Center for Autism Research and Translation, University of California Irvine, Irvine, CA, USA
| | - Gail E Herman
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Irva Hertz-Picciotto
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California Davis, Davis, CA, USA
| | - Patricia Maciel
- Life and Health Sciences Research Institute, School of Medicine, University of Minho, Braga, Portugal
| | - Dara S Manoach
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Maria Rita Passos-Bueno
- Centro de Pesquisas sobre o Genoma Humano e Células tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Antonio M Persico
- Interdepartmental Program 'Autism 0-90', 'Gaetano Martino' University Hospital, University of Messina, Messina, Italy
| | - Alessandra Renieri
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Medical Genetics, , University of Siena, Siena, Italy
- Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - James S Sutcliffe
- Department of Molecular Physiology & Biophysics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Vanderbilt Genetics Institute, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Flora Tassone
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California Davis, Davis, CA, USA
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, CA, USA
| | - Elisabetta Trabetti
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Gabriele Campos
- Centro de Pesquisas sobre o Genoma Humano e Células tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Simona Cardaropoli
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - Diana Carli
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - Marcus C Y Chan
- Department of Pediatrics and Adolescent Medicine, Duchess of Kent Children's Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chiara Fallerini
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Medical Genetics, , University of Siena, Siena, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, Turin, Italy
| | - Ana Cristina Girardi
- Centro de Pesquisas sobre o Genoma Humano e Células tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Emily Hansen-Kiss
- Department of Diagnostic and Biomedical Sciences, University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX, USA
| | - So Lun Lee
- Department of Pediatrics and Adolescent Medicine, Duchess of Kent Children's Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Carla Lintas
- Service for Neurodevelopmental Disorders, University Campus Bio-medico of Rome, Rome, Italy
| | - Yunin Ludena
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California Davis, Davis, CA, USA
| | - Rachel Nguyen
- Center for Autism Research and Translation, University of California Irvine, Irvine, CA, USA
| | - Lisa Pavinato
- Department of Medical Sciences, University of Torino, Turin, Italy
| | - Margaret Pericak-Vance
- The John P Hussman Institute for Human Genomics, The University of Miami Miller School of Medicine, Miami, FL, USA
| | - Isaac N Pessah
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California Davis, Davis, CA, USA
- Department of Molecular Biosciences, University of California Davis, School of Veterinary Medicine, Davis, CA, USA
| | - Rebecca J Schmidt
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California Davis, Davis, CA, USA
| | - Moyra Smith
- Center for Autism Research and Translation, University of California Irvine, Irvine, CA, USA
| | - Claudia I S Costa
- Centro de Pesquisas sobre o Genoma Humano e Células tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Slavica Trajkova
- Department of Medical Sciences, University of Torino, Turin, Italy
| | - Jaqueline Y T Wang
- Centro de Pesquisas sobre o Genoma Humano e Células tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Mullin H C Yu
- Department of Pediatrics and Adolescent Medicine, Duchess of Kent Children's Hospital, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - David J Cutler
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joseph D Buxbaum
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Mark J Daly
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.
| | - Bernie Devlin
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Kathryn Roeder
- Department of Statistics and Data Science, Carnegie Mellon University, Pittsburgh, PA, USA.
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA, USA.
| | - Stephan J Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA.
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Program in Bioinformatics and Integrative Genomics, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
2
|
Bonesteele G, Gargus JJ, Curtin E, Tang M, Rosenbloom B, Kimonis V. Diffuse large B-cell non-Hodgkin's lymphoma in Gaucher disease. Mol Genet Metab Rep 2020; 25:100663. [PMID: 33101982 PMCID: PMC7578544 DOI: 10.1016/j.ymgmr.2020.100663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 11/24/2022] Open
Abstract
Gaucher disease type 1 (GD1) is the most common lysosomal storage disease and affects nearly 1 in 40,000 live births. In addition, it is the most common genetic disorder in the Ashkenazi Jewish population with phenotypic variation presenting in early childhood to asymptomatic nonagenarians. There have been a number of studies showing an increased risk of certain malignancies in patients, especially non- Hodgkin's lymphoma (NHL) and multiple myeloma. We describe a 66-year-old Ashkenazi Jewish male with GD1 who was first started on enzyme replacement therapy (ERT) with imiglucerase for GD1 at age 57 years, followed a year later by the diagnosis of diffuse large b-cell non-Hodgkin's lymphoma (DLBCL). He was treated with R-CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone, plus the monoclonal antibody rituximab), however relapsed and developed myelodysplasia necessitating an allo-stem-cell transplantation but succumbed to severe graft vs. host disease. In addition, we also describe a 38-year-old Ashkenazi Jewish male with GD1 who was diagnosed with DLBCL at age 22 years with Gaucher disease diagnosed on pre-treatment bone marrow biopsy which was confirmed by enzyme assay and genotyping. At age 24 years, he was started on ERT with imiglucerase and at age 35 years, he switched to eliglustat. He has remained in remission from the lymphoma. A meta-analysis of the literature will be elaborated upon and we will discuss the relationship of GD1 to NHL and discuss more recent information regarding lyso-GL1 and the development of NHL and multiple myeloma.
Collapse
Affiliation(s)
- Grant Bonesteele
- Division of Genetics and Genomic Medicine, Department of Pediatrics, University of California, Irvine, United States of America
| | - J Jay Gargus
- Division of Genetics and Genomic Medicine, Department of Pediatrics, University of California, Irvine, United States of America.,Department of Physiology, University of California, Irvine, United States of America
| | - Emily Curtin
- Division of Genetics and Genomic Medicine, Department of Pediatrics, University of California, Irvine, United States of America
| | - Mabel Tang
- Division of Genetics and Genomic Medicine, Department of Pediatrics, University of California, Irvine, United States of America
| | - Barry Rosenbloom
- Samuel Oschin Comprehensive Cancer Institute, Cedars Sinai Medical Center, Beverley Hills, CA, United States of America
| | - Virginia Kimonis
- Division of Genetics and Genomic Medicine, Department of Pediatrics, University of California, Irvine, United States of America
| |
Collapse
|
3
|
Jones SA, Rojas-Caro S, Quinn AG, Friedman M, Marulkar S, Ezgu F, Zaki O, Gargus JJ, Hughes J, Plantaz D, Vara R, Eckert S, Arnoux JB, Brassier A, Le Quan Sang KH, Valayannopoulos V. Survival in infants treated with sebelipase Alfa for lysosomal acid lipase deficiency: an open-label, multicenter, dose-escalation study. Orphanet J Rare Dis 2017; 12:25. [PMID: 28179030 PMCID: PMC5299659 DOI: 10.1186/s13023-017-0587-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/04/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Infants presenting with lysosomal acid lipase deficiency have marked failure to thrive, diarrhea, massive hepatosplenomegaly, anemia, rapidly progressive liver disease, and death typically in the first 6 months of life; the only available potential treatment has been hematopoietic stem cell transplantation, which is associated with high morbidity and mortality in this population. The study objective was to evaluate safety and efficacy (including survival) of enzyme replacement with sebelipase alfa in infants with lysosomal acid lipase deficiency. This is an ongoing multicenter, open-label, phase 2/3 study conducted in nine countries. The study enrolled infants with growth failure prior to 6 months of age with rapidly progressive lysosomal acid lipase deficiency; they received once-weekly doses of sebelipase alfa initiated at 0.35 mg/kg with intrapatient dose escalation up to 5 mg/kg. The main outcome of interest is survival to 12 months and survival beyond 24 months of age. RESULTS Nine patients were enrolled; median age at baseline was 3.0 months (range 1.1-5.8 months). Sixty-seven percent (exact 95% CI 30%-93%) of sebelipase alfa-treated infants survived to 12 months of age compared with 0% (exact 95% CI 0%-16%) for a historical control group (n = 21). Patients who survived to age 12 months exhibited improvements in weight-for-age, reductions in markers of liver dysfunction and hepatosplenomegaly, and improvements in anemia and gastrointestinal symptoms. Three deaths occurred early (first few months of life), two patients died because of advanced disease, and a third patient died following complications of non-protocol-specified abdominal paracentesis. A fourth death occurred at 15 months of age and was related to other clinical conditions. The five surviving patients have survived to age ≥24 months with continued sebelipase alfa treatment; all have displayed marked improvement in growth parameters and liver function. Serious adverse events considered related to sebelipase alfa were reported in one of the nine infants (infusion reaction: tachycardia, pallor, chills, and pyrexia). Most infusion-associated reactions were mild and non-serious. CONCLUSION Sebelipase alfa markedly improved survival with substantial clinically meaningful improvements in growth and other key disease manifestations in infants with rapidly progressive lysosomal acid lipase deficiency TRIAL REGISTRATION: Clinicaltrials.gov NCT01371825 . Registered 9 June 2011.
Collapse
Affiliation(s)
- Simon A. Jones
- Manchester Centre for Genomic Medicine, 6th floor, St Mary’s Hospital, Central Manchester Foundation Trust, University of Manchester, Oxford Road, Manchester, M13 9WL UK
| | | | - Anthony G. Quinn
- Synageva BioPharma Corp., 33 Hayden Avenue, Lexington, MA 02421 USA
- Present: IDBioPharm Consulting, LLC, Boston, MA USA
| | - Mark Friedman
- Alexion Pharmaceuticals, Inc., 100 College Street, New Haven, CT 06510 USA
| | - Sachin Marulkar
- Alexion Pharmaceuticals, Inc., 100 College Street, New Haven, CT 06510 USA
| | - Fatih Ezgu
- Gazi University Faculty of Medicine, Gazi Hospital, 10th Floor, Beşevler Ankara, Turkey
| | - Osama Zaki
- Ain Shams University Pediatrics Hospital, 3, Kamal Raslan, Heliopolis, Cairo, 11771 Egypt
| | - J. Jay Gargus
- University of California, Irvine, 2056 Hewitt Hall, 843 Health Sciences Road, Irvine, CA 92697 USA
| | - Joanne Hughes
- Temple Street Children’s University Hospital, 1 Temple Street, Dublin, 1 Ireland
| | - Dominique Plantaz
- Hôpital Couple-Enfant CHU Grenoble, Avenue Maquis du Grésivaudan, 38700 La Tronche, Grenoble, France
| | - Roshni Vara
- Evelina Children’s Hospital, Westminster Bridge Road, London, SE1 7EH UK
| | - Stephen Eckert
- Synageva BioPharma Corp., 33 Hayden Avenue, Lexington, MA 02421 USA
| | - Jean-Baptiste Arnoux
- Hôpital Necker-Enfants Malades and IMAGINE Institute, 149 Rue de Sèvres, 75015 Paris, France
| | - Anais Brassier
- Hôpital Necker-Enfants Malades and IMAGINE Institute, 149 Rue de Sèvres, 75015 Paris, France
| | - Kim-Hanh Le Quan Sang
- Hôpital Necker-Enfants Malades and IMAGINE Institute, 149 Rue de Sèvres, 75015 Paris, France
| | - Vassili Valayannopoulos
- Hôpital Necker-Enfants Malades and IMAGINE Institute, 149 Rue de Sèvres, 75015 Paris, France
- Present: Sanofi Genzyme, Cambridge, MA USA
| |
Collapse
|
4
|
Schmunk G, Nguyen RL, Ferguson DL, Kumar K, Parker I, Gargus JJ. High-throughput screen detects calcium signaling dysfunction in typical sporadic autism spectrum disorder. Sci Rep 2017; 7:40740. [PMID: 28145469 PMCID: PMC5286408 DOI: 10.1038/srep40740] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/09/2016] [Indexed: 11/11/2022] Open
Abstract
Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders without any defined uniting pathophysiology. Ca2+ signaling is emerging as a potential node in the genetic architecture of the disorder. We previously reported decreased inositol trisphosphate (IP3)-mediated Ca2+ release from the endoplasmic reticulum in several rare monogenic syndromes highly comorbid with autism – fragile X and tuberous sclerosis types 1 and 2 syndromes. We now extend those findings to a cohort of subjects with sporadic ASD without any known mutations. We developed and applied a high throughput Fluorometric Imaging Plate Reader (FLIPR) assay to monitor agonist-evoked Ca2+ signals in human primary skin fibroblasts. Our results indicate that IP3 -mediated Ca2+ release from the endoplasmic reticulum in response to activation of purinergic receptors is significantly depressed in subjects with sporadic as well as rare syndromic forms of ASD. We propose that deficits in IP3-mediated Ca2+ signaling represent a convergent hub function shared across the spectrum of autistic disorders – whether caused by rare highly penetrant mutations or sporadic forms – and holds promise as a biomarker for diagnosis and novel drug discovery.
Collapse
Affiliation(s)
- Galina Schmunk
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California, USA.,Center for Autism Research and Translation, University of California, Irvine, California, USA
| | - Rachel L Nguyen
- Center for Autism Research and Translation, University of California, Irvine, California, USA
| | - David L Ferguson
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California, USA.,Center for Autism Research and Translation, University of California, Irvine, California, USA
| | - Kenny Kumar
- Center for Autism Research and Translation, University of California, Irvine, California, USA
| | - Ian Parker
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California, USA.,Center for Autism Research and Translation, University of California, Irvine, California, USA.,Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, California, USA
| | - J Jay Gargus
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California, USA.,Center for Autism Research and Translation, University of California, Irvine, California, USA.,Division of Human Genetics &Genomics, Department of Pediatrics, School of Medicine, University of California, Irvine, California, USA
| |
Collapse
|
5
|
Jones SA, Valayannopoulos V, Schneider E, Eckert S, Banikazemi M, Bialer M, Cederbaum S, Chan A, Dhawan A, Di Rocco M, Domm J, Enns GM, Finegold D, Gargus JJ, Guardamagna O, Hendriksz C, Mahmoud IG, Raiman J, Selim LA, Whitley CB, Zaki O, Quinn AG. Rapid progression and mortality of lysosomal acid lipase deficiency presenting in infants. Genet Med 2016; 18:452-8. [PMID: 26312827 PMCID: PMC4857209 DOI: 10.1038/gim.2015.108] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/12/2015] [Indexed: 12/18/2022] Open
Abstract
PURPOSE The purpose of this study was to enhance understanding of lysosomal acid lipase deficiency (LALD) in infancy. METHODS Investigators reviewed medical records of infants with LALD and summarized data for the overall population and for patients with and without early growth failure (GF). Kaplan-Meier survival analyses were conducted for the overall population and for treated and untreated patients. RESULTS Records for 35 patients, 26 with early GF, were analyzed. Prominent symptom manifestations included vomiting, diarrhea, and steatorrhea. Median age at death was 3.7 months; estimated probability of survival past age 12 months was 0.114 (95% confidence interval (CI): 0.009-0.220). Among patients with early GF, median age at death was 3.5 months; estimated probability of survival past age 12 months was 0.038 (95% CI: 0.000-0.112). Treated patients (hematopoietic stem cell transplant (HSCT), n = 9; HSCT and liver transplant, n = 1) in the overall population and the early GF subset survived longer than untreated patients, but survival was still poor (median age at death, 8.6 months). CONCLUSIONS These data confirm and expand earlier insights on the progression and course of LALD presenting in infancy. Despite variations in the nature, onset, and severity of clinical manifestations, and treatment attempts, clinical outcome was poor.Genet Med 18 5, 452-458.
Collapse
Affiliation(s)
- Simon A. Jones
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, CMFT, University of Manchester, Manchester, UK
| | | | | | | | | | - Martin Bialer
- North Shore LIG Health System, Manhasset, New York, USA
| | | | - Alicia Chan
- University of Alberta, Edmonton, Alberta, Canada
| | - Anil Dhawan
- King's College Hospital NHS Foundation Trust, London, UK
| | - Maja Di Rocco
- Istituto Giannina Gaslini-Ospedale Pediatrico, Genoa, Italy
| | - Jennifer Domm
- Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee, USA
| | - Gregory M. Enns
- Stanford University School of Medicine, Stanford, California, USA
| | - David Finegold
- Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | | | | | | | - Julian Raiman
- Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | - Osama Zaki
- Ain Shams University Hospital, Cairo, Egypt
| | | |
Collapse
|
6
|
Schmunk G, Boubion BJ, Smith IF, Parker I, Gargus JJ. Shared functional defect in IP₃R-mediated calcium signaling in diverse monogenic autism syndromes. Transl Psychiatry 2015; 5:e643. [PMID: 26393489 PMCID: PMC5068815 DOI: 10.1038/tp.2015.123] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 07/13/2015] [Accepted: 07/27/2015] [Indexed: 01/03/2023] Open
Abstract
Autism spectrum disorder (ASD) affects 2% of children, and is characterized by impaired social and communication skills together with repetitive, stereotypic behavior. The pathophysiology of ASD is complex due to genetic and environmental heterogeneity, complicating the development of therapies and making diagnosis challenging. Growing genetic evidence supports a role of disrupted Ca(2+) signaling in ASD. Here, we report that patient-derived fibroblasts from three monogenic models of ASD-fragile X and tuberous sclerosis TSC1 and TSC2 syndromes-display depressed Ca(2+) release through inositol trisphosphate receptors (IP3Rs). This was apparent in Ca(2+) signals evoked by G protein-coupled receptors and by photoreleased IP3 at the levels of both global and local elementary Ca(2+) events, suggesting fundamental defects in IP3R channel activity in ASD. Given the ubiquitous involvement of IP3R-mediated Ca(2+) signaling in neuronal excitability, synaptic plasticity, gene expression and neurodevelopment, we propose dysregulated IP3R signaling as a nexus where genes altered in ASD converge to exert their deleterious effect. These findings highlight potential pharmaceutical targets, and identify Ca(2+) screening in skin fibroblasts as a promising technique for early detection of individuals susceptible to ASD.
Collapse
Affiliation(s)
- G Schmunk
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA,Center for Autism Research and Translation, University of California, Irvine, CA, USA
| | - B J Boubion
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California, Irvine, CA, USA
| | - I F Smith
- Center for Autism Research and Translation, University of California, Irvine, CA, USA,Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, CA, USA
| | - I Parker
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA,Center for Autism Research and Translation, University of California, Irvine, CA, USA,Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, CA, USA
| | - J J Gargus
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA,Center for Autism Research and Translation, University of California, Irvine, CA, USA,Division of Human Genetics & Genomics, Department of Pediatrics, School of Medicine, University of California, Irvine, CA, USA,Department of Physiology and Biophysics, School of Medicine, University of California, 2056 Hewitt Hall, 843 Health Sciences Road, Irvine, CA 92697-3940, USA. E-mail:
| |
Collapse
|
7
|
Chen X, Ye R, Gargus JJ, Blakely RD, Dobrenis K, Sze JY. Disruption of Transient Serotonin Accumulation by Non-Serotonin-Producing Neurons Impairs Cortical Map Development. Cell Rep 2015; 10:346-358. [PMID: 25600870 PMCID: PMC4824665 DOI: 10.1016/j.celrep.2014.12.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 11/10/2014] [Accepted: 12/15/2014] [Indexed: 01/24/2023] Open
Abstract
Polymorphisms that alter serotonin transporter SERT expression and functionality increase the risks for autism and psychiatric traits. Here, we investigate how SERT controls serotonin signaling in developing CNS in mice. SERT is transiently expressed in specific sets of glutamatergic neurons and uptakes extrasynaptic serotonin during perinatal CNS development. We show that SERT expression in glutamatergic thalamocortical axons (TCAs) dictates sensory map architecture. Knockout of SERT in TCAs causes lasting alterations in TCA patterning, spatial organizations of cortical neurons, and dendritic arborization in sensory cortex. Pharmacological reduction of serotonin synthesis during the first postnatal week rescues sensory maps in SERTGluΔ mice. Furthermore, knockdown of SERT expression in serotonin-producing neurons does not impair barrel maps. We propose that spatiotemporal SERT expression in non-serotonin-producing neurons represents a determinant in early life genetic programming of cortical circuits. Perturbing this SERT function could be involved in the origin of sensory and cognitive deficits associated with neurodevelopmental disorders.
Collapse
Affiliation(s)
- Xiaoning Chen
- Department of Molecular Pharmacology and Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ran Ye
- Departments of Pharmacology & Psychiatry, Silvio O. Conte Center for Neuroscience Research, Vanderbilt University, Nashville, TN 37232, USA
| | - J Jay Gargus
- Center for Autism Research and Translation and Department of Physiology & Biophysics and Section of Human Genetics in Pediatrics, University of California, Irvine, Irvine, CA 92697, USA
| | - Randy D Blakely
- Departments of Pharmacology & Psychiatry, Silvio O. Conte Center for Neuroscience Research, Vanderbilt University, Nashville, TN 37232, USA
| | - Kostantin Dobrenis
- Dominick P. Purpura Department of Neuroscience and Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ji Ying Sze
- Department of Molecular Pharmacology and Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| |
Collapse
|
8
|
Steller J, Gargus JJ, Gibbs LH, Hasso AN, Kimonis VE. Mild phenotype in a male with pyruvate dehydrogenase complex deficiency associated with novel hemizygous in-frame duplication of the E1α subunit gene (PDHA1). Neuropediatrics 2014; 45:56-60. [PMID: 23572181 DOI: 10.1055/s-0033-1341601] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pyruvate dehydrogenase complex (PDHC) deficiency is an inborn error of metabolism that occurs most commonly due to mutations in the X-linked E1α subunit gene (PDHA1). We report a novel duplication of PDHA1 associated with a mild phenotype in a 15-year-old boy who was diagnosed with PDHC deficiency at 4 years of age following a history of seizures and lactic acidosis. The novel c.1087_1119 mutation in exon 11 resulted in an in-frame duplication of 11 amino acids. Measurements of PDHC activity in cultured skin fibroblasts were low, corresponding to 18.6 and 11.6% of the mean with respect to prior controls, whereas the E1 PDH component was absent. He has borderline intellectual functioning and maintains normal lactate levels on a ketogenic diet in between relapses due to illness. Review of the literature reveals wide variation of clinical phenotype in patients with mutations of the E1α subunit gene (PDHA1). There appears to be a higher incidence of normal or borderline intellectual ability in individuals who have insertions or deletions that are in-frame versus those that are out-of-frame. Furthermore, there is no correlation between mean residual PDH activity and phenotype in these patients.
Collapse
Affiliation(s)
- J Steller
- Division of Genetics and Metabolism, Department of Pediatrics, University of California-Irvine, Orange, California, United States
| | - J J Gargus
- Division of Genetics and Metabolism, Department of Pediatrics, University of California-Irvine, Orange, California, United States
| | - L H Gibbs
- Department of Radiology, University of California-Irvine, Orange, California, United States
| | - A N Hasso
- Department of Radiology, University of California-Irvine, Orange, California, United States
| | - V E Kimonis
- Division of Genetics and Metabolism, Department of Pediatrics, University of California-Irvine, Orange, California, United States
| |
Collapse
|
9
|
Abstract
Autism spectrum disorder (ASD) is a syndrome that affects normal brain development and is characterized by impaired social interaction as well as verbal and non-verbal communication and by repetitive, stereotypic behavior. ASD is a complex disorder arising from a combination of multiple genetic and environmental factors that are independent from racial, ethnic and socioeconomical status. The high heritability of ASD suggests a strong genetic basis for the disorder. Furthermore, a mounting body of evidence implies a role of various ion channel gene defects (channelopathies) in the pathogenesis of autism. Indeed, recent genome-wide association, and whole exome- and whole-genome resequencing studies linked polymorphisms and rare variants in calcium, sodium and potassium channels and their subunits with susceptibility to ASD, much as they do with bipolar disorder, schizophrenia and other neuropsychiatric disorders. Moreover, animal models with these genetic variations recapitulate endophenotypes considered to be correlates of autistic behavior seen in patients. An ion flux across the membrane regulates a variety of cell functions, from generation of action potentials to gene expression and cell morphology, thus it is not surprising that channelopathies have profound effects on brain functions. In the present work, we summarize existing evidence for the role of ion channel gene defects in the pathogenesis of autism with a focus on calcium signaling and its downstream effects.
Collapse
Affiliation(s)
- Galina Schmunk
- Department of Physiology and Biophysics, University of California Irvine, CA, USA ; UCI Center for Autism Research and Treatment, School of Medicine, University of California Irvine, CA, USA
| | | |
Collapse
|
10
|
Abstract
The calcium ion is one of the most versatile, ancient, and universal of biological signaling molecules, known to regulate physiological systems at every level from membrane potential and ion transporters to kinases and transcription factors. Disruptions of intracellular calcium homeostasis underlie a host of emerging diseases, the calciumopathies. Cytosolic calcium signals originate either as extracellular calcium enters through plasma membrane ion channels or from the release of an intracellular store in the endoplasmic reticulum (ER) via inositol triphosphate receptor and ryanodine receptor channels. Therefore, to a large extent, calciumopathies represent a subset of the channelopathies, but include regulatory pathways and the mitochondria, the major intracellular calcium repository that dynamically participates with the ER stores in calcium signaling, thereby integrating cellular energy metabolism into these pathways, a process of emerging importance in the analysis of the neurodegenerative and neuropsychiatric diseases. Many of the calciumopathies are common complex polygenic diseases, but leads to their understanding come most prominently from rare monogenic channelopathy paradigms. Monogenic forms of common neuronal disease phenotypes-such as seizures, ataxia, and migraine-produce a constitutionally hyperexcitable tissue that is susceptible to periodic decompensations. The gene families and genetic lesions underlying familial hemiplegic migraine, FHM1/CACNA1A, FHM2/ATP1A2, and FHM3/SCN1A, and monogenic mitochondrial migraine syndromes, provide a robust platform from which genes, such as CACNA1C, which encodes the calcium channel mutated in Timothy syndrome, can be evaluated for their role in autism and bipolar disease.
Collapse
Affiliation(s)
- J Jay Gargus
- Department of Physiology & Biophysics, Section of Human Genetics, School of Medicine, University of California-Irvine, Irvine, CA 92697, USA.
| |
Collapse
|
11
|
|
12
|
Tong X, Shih C, Ma S, Gargus JJ. Functional genetics of migraine: analysis of sodium pump and P/Q channel homologs from C elegans. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1168.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - J. Jay Gargus
- Physiology & Biophysics
- Section of Human GeneticsDept PediatricsUniversity of CaliforniaIrvineIrvineCA
| |
Collapse
|
13
|
|
14
|
|
15
|
Gargus JJ, Tournay A. Novel mutation confirms seizure locus SCN1A is also familial hemiplegic migraine locus FHM3. Pediatr Neurol 2007; 37:407-10. [PMID: 18021921 PMCID: PMC2151385 DOI: 10.1016/j.pediatrneurol.2007.06.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [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] [Received: 03/14/2007] [Revised: 04/25/2007] [Accepted: 06/29/2007] [Indexed: 11/20/2022]
Abstract
Although SCN1A, the gene encoding the neuronal voltage-gated sodium channel, type 1A, is a well-recognized target of mutations underlying a spectrum of epilepsy syndromes, and lies within an extended 12-Mb disease-associated haplotype at the familial hemiplegic migraine-3 locus, it remains to be confirmed that mutations within this gene itself cause syndromes that include migraine phenotypes. The novel T1174S missense mutation of this gene was detected segregating in a family with a heterozygous female child who presented with myoclonus and an abnormal electroencephalogram, and in her heterozygous mother, who had an ataxic migraine syndrome similar to that of her own mother. This three-generation family exhibits the broad phenotypic spectrum of the dominant neuronal hyperexcitability syndromes produced by even a given allele of this sodium channel gene. It also exhibits the second allele of this sodium channel gene associated with a migraine syndrome similar to those caused at the two other familial hemiplegic migraine loci, confirming that this gene itself, not some linked gene, is the familial hemiplegic migraine-3 locus.
Collapse
Affiliation(s)
- J Jay Gargus
- Department of Physiology and Biophysics, School of Medicine, University of California Irvine, Irvine, CA 92697-4034, USA.
| | | |
Collapse
|
16
|
Bannwarth S, Procaccio V, Rouzier C, Fragaki K, Poole J, Chabrol B, Desnuelle C, Pouget J, Azulay JP, Attarian S, Pellissier JF, Gargus JJ, Abdenur JE, Mozaffar T, Calvas P, Labauge P, Pages M, Wallace DC, Lambert JC, Paquis-Flucklinger V. Rapid identification of mitochondrial DNA (mtDNA) mutations in neuromuscular disorders by using surveyor strategy. Mitochondrion 2007; 8:136-45. [PMID: 18078792 DOI: 10.1016/j.mito.2007.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 10/22/2007] [Accepted: 10/26/2007] [Indexed: 11/18/2022]
Abstract
Mutations of mitochondrial genome are responsible for respiratory chain defects in numerous patients. We have used a strategy, based on the use of a mismatch-specific DNA endonuclease named " Surveyor Nuclease", for screening the entire mtDNA in a group of 50 patients with neuromuscular features, suggesting a respiratory chain dysfunction. We identified mtDNA mutations in 20% of patients (10/50). Among the identified mutations, four are not found in any mitochondrial database and have not been reported previously. We also confirm that mtDNA polymorphisms are frequently found in a heteroplasmic state (15 different polymorphisms were identified among which five were novel).
Collapse
Affiliation(s)
- S Bannwarth
- Department of Medical Genetics, Archet 2 Hospital, CHU Nice, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Liang B, Moussaif M, Kuan CJ, Gargus JJ, Sze JY. Serotonin targets the DAF-16/FOXO signaling pathway to modulate stress responses. Cell Metab 2006; 4:429-40. [PMID: 17141627 DOI: 10.1016/j.cmet.2006.11.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 04/10/2006] [Accepted: 11/09/2006] [Indexed: 11/26/2022]
Abstract
Stress response is a fundamental form of behavioral and physiological plasticity. Here we describe how serotonin (5HT) governs stress behavior by regulating DAF-2 insulin/IGF-1 receptor signaling to the DAF-16/FOXO transcription factor at the nexus of development, metabolism, immunity, and stress responses in C. elegans. Serotonin-deficient tph-1 mutants, like daf-2 mutants, exhibit DAF-16 nuclear accumulation and constitutive physiological stress states. Exogenous 5HT and fluoxetine (Prozac) prevented DAF-16 nuclear accumulation in wild-type animals under stresses. Genetic analyses imply that DAF-2 is a downstream target of 5HT signaling and that distinct serotonergic neurons act through distinct 5HT receptors to influence distinct DAF-16-mediated stress responses. We suggest that modulation of FOXO by 5HT represents an ancient feature of stress physiology and that the C. elegans is a genetically tractable model that can be used to delineate the molecular mechanisms and drug actions linking 5HT, neuroendocrine signaling, immunity, and mitochondrial function.
Collapse
Affiliation(s)
- Bin Liang
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, Irvine, California 92697, USA
| | | | | | | | | |
Collapse
|
18
|
|
19
|
Abstract
Scores of monogenic Mendelian ion channel diseases serve to anchor the pathophysiology of the channelopathies, but there are also now clear examples of environmental, pharmacogenetic, and acquired channelopathy mechanisms. The cardinal feature of heritable ion channel disease is a periodic disturbance of rhythmic function in constitutionally hyperexcitable tissue. While the complexity of neuroanatomy obscures functional analysis of mutations causing monogenic seizure, ataxia, or migraine syndromes, extrapolation from the cardiac (Long QT [LQT]) and muscle (Periodic Paralysis) channelopathy syndromes provides a simplified predictive framework of molecular pathology: electrically stabilizing potassium ion (K(+)) and chloride ion (Cl(-)) channels, likely having lesions that diminish their current, and excitatory Na(+) channels, likely having gain-of-function lesions. The voltage-gated calcium channel gene family that contains CACNA1C, the newest LQT locus, causing Timothy Syndrome with a phenotype including autism, has proven to be particularly informative for its members' ability to tie the various central nervous system (CNS) phenotypes together in an interpretable fashion, now including direct extension to the classically multigenic neuropsychiatric phenotypes. Features of a promising ion channel candidate gene arise from its broad locus, gene family, nature of alleles, physiology and pharmacology, tissue expression profile, and phenotype in model organisms. KCNN3 is explored as a paradigm to consider.
Collapse
Affiliation(s)
- J Jay Gargus
- Department of Physiology, Section of Human Genetics, University of California, Irvine, California 92697-4034, USA.
| |
Collapse
|
20
|
Segall L, Mezzetti A, Scanzano R, Gargus JJ, Purisima E, Blostein R. Alterations in the alpha2 isoform of Na,K-ATPase associated with familial hemiplegic migraine type 2. Proc Natl Acad Sci U S A 2005; 102:11106-11. [PMID: 16037212 PMCID: PMC1178013 DOI: 10.1073/pnas.0504323102] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [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: 11/18/2022] Open
Abstract
A number of missense mutations in the Na,K-ATPase alpha2 catalytic subunit have been identified in familial hemiplegic migraine with aura. Two alleles (L764P and W887R) showed loss-of-function, whereas a third (T345A) is fully functional but with altered Na,K-ATPase kinetics. This study describes two additional mutants, R689Q and M731T, originally identified by Vanmolkot et al. [Vanmolkot, K. R., et al. (2003) Ann. Neurol. 54, 360-366], which we show here to also be functional and kinetically altered. Both mutants have reduced catalytic turnover and increased apparent affinity for extracellular K(+). For both R689Q and M731T, sensitivity to vanadate inhibition is decreased, suggesting that the steady-state E(1) <==> E(2) poise of the enzyme is shifted toward E(1). Whereas the K'(ATP) is not affected by the R689Q replacement, the M731T mutant has an increase in apparent affinity for ATP. Analysis of the structural changes effected by T345A, R689Q, and M731T mutations, based on homologous replacements in the known crystal structure of the sarcoplasmic reticulum Ca-ATPase, provides insights into the molecular bases for the kinetic alterations. It is suggested that the disease phenotype is the consequence of lowered molecular activity of the alpha2 pump isoform due to either decreased K(+) affinity (T345A) or catalytic turnover (R689Q and M731T), thus causing a delay in extracellular K(+) clearance and/or altered localized Ca(2+) handling/signaling secondary to reduced activity in colocalized Na(+)/Ca(2+) exchange.
Collapse
Affiliation(s)
- Laura Segall
- Departments of Biochemistry and Medicine, McGill University and Montreal General Hospital Research Institute, Montreal, Quebec, Canada H3G 1A4
| | | | | | | | | | | |
Collapse
|
21
|
Abstract
A random retrospective chart review was conducted to document serum carnitine levels on 100 children with autism. Concurrently drawn serum pyruvate, lactate, ammonia, and alanine levels were also available in many of these children. Values of free and total carnitine (p < 0.001), and pyruvate (p = 0.006) were significantly reduced while ammonia and alanine levels were considerably elevated (p < 0.001) in our autistic subjects. The relative carnitine deficiency in these patients, accompanied by slight elevations in lactate and significant elevations in alanine and ammonia levels, is suggestive of mild mitochondrial dysfunction. It is hypothesized that a mitochondrial defect may be the origin of the carnitine deficiency in these autistic children.
Collapse
Affiliation(s)
- Pauline A Filipek
- Department of Pediatrics, College of Medicine, University of California, Irvine, CA, USA.
| | | | | | | | | |
Collapse
|
22
|
Segall L, Scanzano R, Kaunisto MA, Wessman M, Palotie A, Gargus JJ, Blostein R. Kinetic Alterations due to a Missense Mutation in the Na,K-ATPase α2 Subunit Cause Familial Hemiplegic Migraine Type 2. J Biol Chem 2004; 279:43692-6. [PMID: 15308625 DOI: 10.1074/jbc.m407471200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [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: 11/06/2022] Open
Abstract
A number of missense mutations in the ATP1A2 gene, which encodes the Na,K-ATPase alpha2 subunit, have been identified in familial hemiplegic migraine with aura. Loss of function and haploinsufficiency have been the suggested mechanisms in mutants for which functional analysis has been reported. This paper describes a kinetic analysis of mutant T345A, recently identified in a detailed genetic analysis of a large Finnish family (Kaunisto, M. A., Harno, H., Vanmolkot, K. R., Gargus, J. J., Sun, G., Hamalainen, E., Liukkonen, E., Kallela, M., van den Maagdenberg, A. M., Frants, R. R., Farkkila, M., Palotie, A., and Wessman, M. (2004) Neurogenetics 5, 141-146). Introducing T345A into the conserved rat alpha2 enzyme does not alter cell growth or catalytic turnover but causes a substantial decrease in apparent K+ affinity (2-fold increase in K0.5(K+)). In view of the location of Thr-345 in the cytoplasmic stalk domain adjacent to transmembrane segment 4, the 2-fold increase in K0.5(K+) is probably due to T345A replacement altering K+ occlusion/deocclusion. Faster K+ deocclusion of the mutant via the E2(K) + ATP --> E1.ATP + K+ partial reaction is evidenced in (i) a marked increase (300%) in K+ stimulation of Na-ATPase at micromolar ATP, (ii) a 4-fold decrease in KATP, and (iii) only a modest increase (approximately 3-fold) in I50 for vanadate, which was used as a probe of the steady state E1/E2 conformational equilibrium. We suggest that the decreased apparent K+ affinity is the basis for a reduced rate of extracellular K+ removal, which delays the recovery phase of nerve impulse transmission in the central nervous system and, thereby, the clinical picture of migraine with aura. This is the first demonstration of a mutation that leads to a disease associated with a kinetically altered but fully functional Na,K-ATPase, refining the molecular mechanism of pathogenesis in familial hemiplegic migraine.
Collapse
Affiliation(s)
- Laura Segall
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1A4, Canada
| | | | | | | | | | | | | |
Collapse
|
23
|
Kaunisto MA, Harno H, Vanmolkot KRJ, Gargus JJ, Sun G, Hämäläinen E, Liukkonen E, Kallela M, van den Maagdenberg AMJM, Frants RR, Färkkilä M, Palotie A, Wessman M. A novel missense ATP1A2 mutation in a Finnish family with familial hemiplegic migraine type 2. Neurogenetics 2004; 5:141-6. [PMID: 15133718 DOI: 10.1007/s10048-004-0178-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [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] [Received: 12/10/2003] [Accepted: 03/25/2004] [Indexed: 10/26/2022]
Abstract
Familial hemiplegic migraine (FHM), a rare autosomal dominant subtype of migraine with aura, has been linked to two chromosomal loci, 19p13 and 1q23. Mutations in the Na+K+-ATPase alpha2 subunit gene, ATP1A2, on 1q23 have recently been shown to cause familial hemiplegic migraine type 2 (FHM2). We sequenced the coding regions of this gene in a Finnish chromosome 1q23-linked FHM family with associated symptoms such as coma and identified a novel A1033G mutation in exon 9. This mutation results in a threonine-to-alanine substitution at codon 345. This residue is located in a highly conserved N-terminal region of the M4-5 loop of the Na+,K+-ATPase. Furthermore, the T345A mutation co-segregated with the disorder in our family and was not present in 132 healthy Finnish control individuals. For these reasons it is most likely the FHM-causing mutation in this family.
Collapse
Affiliation(s)
- M A Kaunisto
- Biomedicum Helsinki, Research Program in Molecular Medicine, University of Helsinki, Helsinki, Finland.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Kolski-Andreaco A, Tomita H, Shakkottai VG, Gutman GA, Cahalan MD, Gargus JJ, Chandy KG. SK3-1C, a Dominant-negative Suppressor of SKCa and IKCa Channels. J Biol Chem 2004; 279:6893-904. [PMID: 14638680 DOI: 10.1074/jbc.m311725200] [Citation(s) in RCA: 26] [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: 11/06/2022] Open
Abstract
Small conductance Ca2+-activated K+ channels, products of the SK1-SK3 genes, regulate membrane excitability both within and outside the nervous system. We report the characterization of a SK3 variant (SK3-1C) that differs from SK3 by utilizing an alternative first exon (exon 1C) in place of exon 1A used by SK3, but is otherwise identical to SK3. Quantitative RT-PCR detected abundant expression of SK3-1C transcripts in human lymphoid tissues, skeletal muscle, trachea, and salivary gland but not the nervous system. SK3-1C did not produce functional channels when expressed alone in mammalian cells, but suppressed SK1, SK2, SK3, and IKCa1 channels, but not BKCa or KV channels. Confocal microscopy revealed that SK3-1C sequestered SK3 protein intracellularly. Dominant-inhibitory activity of SK3-1C was not due to a nonspecific calmodulin sponge effect since overexpression of calmodulin did not reverse SK3-1C-mediated intracellular trapping of SK3 protein, and calmodulin-Ca2+-dependent inactivation of CaV channels was not affected by SK3-1C overexpression. Deletion analysis identified a dominant-inhibitory segment in the SK3-1C C terminus that resembles tetramerization-coiled-coiled domains reported to enhance tetramer stability and selectivity of multimerization of many K+ channels. SK3-1C may therefore suppress calmodulin-gated SKCa/IKCa channels by trapping these channel proteins intracellularly via subunit interactions mediated by the dominant-inhibitory segment and thereby reduce functional channel expression on the cell surface. Such family-wide dominant-negative suppression by SK3-1C provides a powerful mechanism to titrate membrane excitability and is a useful approach to define the functional in vivo role of these channels in diverse tissues by their targeted silencing.
Collapse
Affiliation(s)
- Aaron Kolski-Andreaco
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California 92697, USA
| | | | | | | | | | | | | |
Collapse
|
25
|
Sun G, Gargus JJ, Ta DT, Vickery LE. Identification of a novel candidate gene in the iron-sulfur pathway implicated in ataxia-susceptibility: human gene encoding HscB, a J-type co-chaperone. J Hum Genet 2003; 48:415-419. [PMID: 12938016 DOI: 10.1007/s10038-003-0048-9] [Citation(s) in RCA: 22] [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] [Received: 05/12/2003] [Accepted: 05/27/2003] [Indexed: 11/28/2022]
Abstract
Iron-sulfur proteins participate in a wide range of biochemical processes, including many that are central to mitochondrial electron transfer and energy metabolism. Mutations in two such proteins, frataxin and ABCB7, cause Friedreich ataxia and X-linked sideroblastic anemia with ataxia, respectively, rendering other participants in this pathway functional candidates for hereditary ataxia syndromes. Recently frataxin was shown to have an identical phylogenetic distribution with two genes and was most likely specifically involved in the same sub-process in iron-sulfur cluster assembly as one gene, designated hscB, in bacteria. To set the stage for an analysis of the potential role of this candidate gene in human disease, we defined the human HscB cDNA, its genomic locus, and its pattern of expression in normal human tissues. The isolated human HscB cDNA spans 785 bp and encodes a conserved 235-amino-acid protein, including a putative mitochondrial import leader. The HscB gene is found at chromosome 22q11-12 and is composed of six exons and five introns. Northern blot analyses of RNA from adult and fetal tissues defined a pattern of expression in mitochondria-rich tissues similar to that of frataxin, an expression pattern compatible with its implied role in mitochondrial energetics and related disease phenotypes.
Collapse
Affiliation(s)
- Guifeng Sun
- Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA
| | - J Jay Gargus
- Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA.
- Division of Human Genetics, Department of Pediatrics, University of California, Irvine, CA, USA.
| | - Dennis T Ta
- Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA
| | - Larry E Vickery
- Department of Physiology and Biophysics, University of California, Sprague Hall, Rm 328, 839 Medical Sciences Court, Irvine, CA 92697-4034, USA
| |
Collapse
|
26
|
Filipek PA, Juranek J, Smith M, Mays LZ, Ramos ER, Bocian M, Masser-Frye D, Laulhere TM, Modahl C, Spence MA, Gargus JJ. Mitochondrial dysfunction in autistic patients with 15q inverted duplication. Ann Neurol 2003; 53:801-4. [PMID: 12783428 DOI: 10.1002/ana.10596] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [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: 11/10/2022]
Abstract
Two autistic children with a chromosome 15q11-q13 inverted duplication are presented. Both had uneventful perinatal courses, normal electroencephalogram and magnetic resonance imaging scans, moderate motor delay, lethargy, severe hypotonia, and modest lactic acidosis. Both had muscle mitochondrial enzyme assays that showed a pronounced mitochondrial hyperproliferation and a partial respiratory chain block most parsimoniously placed at the level of complex III, suggesting candidate gene loci for autism within the critical region may affect pathways influencing mitochondrial function.
Collapse
Affiliation(s)
- Pauline A Filipek
- Department of Pediatrics, College of Medicine, University of California, Irvine, CA, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Tomita H, Shakkottai VG, Gutman GA, Sun G, Bunney WE, Cahalan MD, Chandy KG, Gargus JJ. Novel truncated isoform of SK3 potassium channel is a potent dominant-negative regulator of SK currents: implications in schizophrenia. Mol Psychiatry 2003; 8:524-35, 460. [PMID: 12808432 DOI: 10.1038/sj.mp.4001271] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [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: 11/09/2022]
Abstract
The small-conductance calcium-activated K(+) channel SK3 (SKCa3/KCNN3) regulates electrical excitability and neurotransmitter release in monoaminergic neurons, and has been implicated in schizophrenia, ataxia and anorexia nervosa. We have identified a novel SK3 transcript, SK3-1B that utilizes an alternative first exon (exon 1B), but is otherwise identical to SK3. SK3-1B, mRNA is widely distributed in human tissues and is present at 20-60% of SK3 in the brain. The SK3-1B protein lacks the N-terminus and first transmembrane segment, and begins eight residues upstream of the second transmembrane segment. When expressed alone, SK3-1B did not produce functional channels, but selectively suppressed endogenous SK3 currents in the pheochromocytoma cell line, PC12, in a dominant-negative fashion. This dominant inhibitory effect extended to other members of the SK subfamily, but not to voltage-gated K(+) channels, and appears to be due to intracellular trapping of endogenous SK channels. The effect of SK3-1B expression is very similar to that produced by expression of the rare SK3 truncation allele, SK3-Delta, found in a patient with schizophrenia. Regulation of SK3 and SK3-1B levels may provide a potent mechanism to titrate neuronal firing rates and neurotransmitter release in monoaminergic neurons, and alterations in the relative abundance of these proteins could contribute to abnormal neuronal excitability, and to the pathogenesis of schizophrenia.
Collapse
Affiliation(s)
- H Tomita
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697-4034, USA
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Gargus JJ. Unraveling monogenic channelopathies and their implications for complex polygenic disease. Am J Hum Genet 2003; 72:785-803. [PMID: 12629596 PMCID: PMC1180344 DOI: 10.1086/374317] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [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: 01/16/2003] [Accepted: 01/16/2003] [Indexed: 01/08/2023] Open
Abstract
Ion channels are a large family of >400 related proteins representing >1% of our genetic endowment; however, ion-channel diseases reflect a relatively new category of inborn error. They were first recognized in 1989, with the discovery of cystic fibrosis transmembrane conductance regulator, and rapidly advanced as positional and functional studies converged in the dissection of components of the action potential of excitable tissues. Although it remains true that diseases of excitable tissue still most clearly illustrate this family of disease, ion-channel disorders now cover the gamut of medical disciplines, causing significant pathology in virtually every organ system, producing a surprising range of often unanticipated symptoms, and providing valuable targets for pharmacological intervention. Many of the features shared among the monogenic ion-channel diseases provide a general framework for formulating a foundation for considering their intrinsically promising role in polygenic disease. Since an increasingly important approach to the identification of genes underlying polygenic disease is to identify "functional candidates" within a critical region and to test their disease association, it becomes increasingly important to appreciate how these ion-channel mechanisms can be implicated in pathophysiology.
Collapse
Affiliation(s)
- J Jay Gargus
- Department Physiology and Biophysics and Division of Human Genetics, Department of Pediatrics, University of California, Irvine, CA 92697, USA.
| |
Collapse
|
29
|
Gargus JJ, Boyle K, Bocian M, Roe DS, Vianey-Saban C, Roe CR. Respiratory complex II defect in siblings associated with a symptomatic secondary block in fatty acid oxidation. J Inherit Metab Dis 2003; 26:659-70. [PMID: 14707514 DOI: 10.1023/b:boli.0000005659.52200.c1] [Citation(s) in RCA: 9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The mitochondrial oxidative phosphorylation and fatty acid oxidation pathways have traditionally been considered independent major sources of cellular energy production; however, case reports of patients with specific enzymatic defects in either pathway have suggested the potential for a complex interference between the two. This study documents a new site of interference between the two pathways, a site in respiratory complex II capable of producing clinical signs of a block in fatty acid oxidation and reduced in vitro activity of acyl-CoA dehydrogenases. The initial patient, and later her newborn sibling, had mildly dysmorphic features, lactic acidosis and a defect in mitochondrial respiratory complex II associated with many biochemical features of a block in fatty acid oxidation. Results of in vitro probing of intact fibroblasts from both patients with methyl[2H3]palmitate and L-carnitine revealed greatly increased [2H3]butyrylcarnitine; however, the ratio of dehydrogenase activity with butyryl-CoA with anti-MCAD inactivating antibody (used to reveal SCAD-specific activity) to that with octanoyl-CoA was normal, excluding a selective SCAD or MCAD deficiency. Respiratory complex II was defective in both patients, with an absent thenoyltrifluoroacetone-sensitive succinate Q reductase activity that was partially restored by supplementation with duroquinone. Although secondary, the block in fatty acid oxidation was a major management problem since attempts to provide essential fatty acids precipitated acidotic decompensations. This study reinforces the need to pursue broadly the primary genetic defect within these two pathways, making full use of increasingly available functional and molecular diagnostic tools.
Collapse
Affiliation(s)
- J J Gargus
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697-4034, USA.
| | | | | | | | | | | |
Collapse
|
30
|
Nyhan WL, Gargus JJ, Boyle K, Selby R, Koch R. Progressive neurologic disability in methylmalonic acidemia despite transplantation of the liver. Eur J Pediatr 2002; 161:377-9. [PMID: 12111189 DOI: 10.1007/s00431-002-0970-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2001] [Accepted: 04/17/2002] [Indexed: 11/26/2022]
Abstract
UNLABELLED Methylmalonic acidemia unresponsive to cobalamin is often fatal in infancy. Patients have been considered candidates for hepatic transplantation and experience has been that the procedure eliminates the life-threatening episodes of ketoacidosis that characterize this disease. CONCLUSION experience with a 24-year-old patient treated with hepatic transplantation indicates that this procedure does not prevent progressive renal failure and neurologic dysfunction.
Collapse
Affiliation(s)
- William L Nyhan
- UCSD Pediatrics (0830), 9500 Gilman Drive, La Jolla, CA 92093-0830, USA.
| | | | | | | | | |
Collapse
|
31
|
Abstract
KCNN3 is a member of the gene family, KCNN1-4, encoding the small and intermediate conductance calcium-activated potassium channels. Long CAG-repeat alleles of this gene have been found to be over-represented in patients with schizophrenia in a number of population-based association studies, and this gene maps to human chromosome 1q21, a region recently implicated in schizophrenia by linkage. To set the stage for a further functional evaluation of KCNN3, we defined the nature of the genomic locus in the size, structure, and sequence of its introns and exons and the function of potential upstream regulatory regions. We isolated P1-derived artificial chromosome (PAC) clones from a genomic library and identified an overlapping available bacterial artificial chromosome (BAC) clone. Cosmids subcloned from the PAC and BAC clones were then sequenced and merged with the sequence in the public database. The KCNN3 gene spans over 163.1 kb and is composed of eight exons and seven introns. All of the exon-intron junctions conform closely to consensus splice sites. The proximal 2.5 kb of the 5'-flanking sequence was obtained and analyzed for potential transcription factor binding sites. In the proximal 2.5 kb upstream region, potential sites for the Ikaros factor (IK2), homeodomain factor Nkx-2.5/Csx (NKX25), nuclear factor of activated T-cells (NFAT), upstream stimulating factor (USF), c-AMP responsive element binding protein (CREB), POU factor Brn2 (BRN-2), myeloid zinc finger protein (MZF1), vitellogenin binding protein (VBP), HNF3 forkhead homologue 2 (HFH2), and transcription initiation were identified, as well as several potential AP-1 and AP-4 sites. Finally, a 2261-bp fragment of this upstream region was cloned into a promoterless pGL3-luciferase vector, where it produced orientation-dependent expression of the reporter gene in transiently transfected PC12 cells, cells which natively express functional KCNN3 channels, suggesting that this cloned fragment includes competent promoter elements of this gene.
Collapse
Affiliation(s)
- G Sun
- Department of Physiology and Biophysics, University of California, Irvine, 92697-4560, USA
| | | | | | | |
Collapse
|
32
|
Shakkottai VG, Regaya I, Wulff H, Fajloun Z, Tomita H, Fathallah M, Cahalan MD, Gargus JJ, Sabatier JM, Chandy KG. Design and characterization of a highly selective peptide inhibitor of the small conductance calcium-activated K+ channel, SkCa2. J Biol Chem 2001; 276:43145-51. [PMID: 11527975 DOI: 10.1074/jbc.m106981200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [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: 11/06/2022] Open
Abstract
Apamin-sensitive small conductance calcium-activated potassium channels (SKCa1-3) mediate the slow afterhyperpolarization in neurons, but the molecular identity of the channel has not been defined because of the lack of specific inhibitors. Here we describe the structure-based design of a selective inhibitor of SKCa2. Leiurotoxin I (Lei) and PO5, peptide toxins that share the RXCQ motif, potently blocked human SKCa2 and SKCa3 but not SKCa1, whereas maurotoxin, Pi1, Tskappa, and PO1 were ineffective. Lei blocked these channels more potently than PO5 because of the presence of Ala(1), Phe(2), and Met(7). By replacing Met(7) in the RXCQ motif of Lei with the shorter, unnatural, positively charged diaminobutanoic acid (Dab), we generated Lei-Dab(7), a selective SKCa2 inhibitor (K(d) = 3.8 nm) that interacts with residues in the external vestibule of the channel. SKCa3 was rendered sensitive to Lei-Dab(7) by replacing His(521) with the corresponding SKCa2 residue (Asn(367)). Intracerebroventricular injection of Lei-Dab(7) into mice resulted in no gross central nervous system toxicity at concentrations that specifically blocked SKCa2 homotetramers. Lei-Dab(7) will be a useful tool to investigate the functional role of SKCa2 in mammalian tissues.
Collapse
Affiliation(s)
- V G Shakkottai
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
PURPOSE Primary carnitine deficiency is an autosomal recessive disorder of fatty acid oxidation resulting from defective carnitine transport. This disease is caused by mutations in the carnitine transporter gene SLC22A5. The objective of this study was to extend mutational analysis to four additional families with this disorder and determine whether recurrent mutations could be found. METHODS The SLC22A5 gene encoding the OCTN2 carnitine transporter was sequenced, and the missense mutations identified were expressed in Chinese hamster ovary (CHO) cells. RESULTS DNA sequencing revealed four novel mutations (Y4X; dup 254-264, 133X; R19P; R399Q). Alleles introducing premature STOP codons reduced the levels of OCTN2 mRNA. Carnitine transport in CHO cells expressing the R19P and R399Q mutations was reduced to < 5% of normal. The 133X mutation was found in two unrelated European families. Two patients within the same family, both homozygous for the same mutation (R399Q) had completely different clinical presentation. CONCLUSIONS Heterogeneous mutations in the SLC22A5 gene cause primary carnitine deficiency. Different presentations are observed even in children with identical mutations.
Collapse
Affiliation(s)
- Y Wang
- Division of Medical Genetics, Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Miller MJ, Rauer H, Tomita H, Rauer H, Gargus JJ, Gutman GA, Cahalan MD, Chandy KG. Nuclear localization and dominant-negative suppression by a mutant SKCa3 N-terminal channel fragment identified in a patient with schizophrenia. J Biol Chem 2001; 276:27753-6. [PMID: 11395478 DOI: 10.1074/jbc.c100221200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [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: 11/06/2022] Open
Abstract
The small conductance calcium-activated K+ channel gene SKCa3/KCNN3 maps to 1q21, a region strongly linked to schizophrenia. Recently, a 4-base pair deletion in SKCa3 was reported in a patient with schizophrenia, which truncates the protein at the end of the N-terminal cytoplasmic region (SKCa3Delta). We generated a green fluorescent protein-SKCa3 N-terminal construct (SKCa3-1/285) that is identical to SKCa3Delta except for the last two residues. Using confocal microscopy we demonstrate that SKCa3-1/285 localizes rapidly and exclusively to the nucleus of mammalian cells like several other pathogenic polyglutamine-containing proteins. This nuclear targeting is mediated in part by two polybasic sequences present at the C-terminal end of SKCa3-1/285. In contrast, full-length SKCa3, SKCa2, and IKCa1 polypeptides are all excluded from the nucleus and express as functional channels. When overexpressed in human Jurkat T cells, SKCa3-1/285 can suppress endogenous SKCa2 currents but not voltage-gated K+ currents. This dominant-negative suppression is most likely mediated through the co-assembly of SKCa3-1/285 with native subunits and the formation of non-functional tetramers. The nuclear localization of SKCa3-1/285 may alter neuronal architecture, and its ability to dominantly suppress endogenous small conductance K(Ca) currents may affect patterns of neuronal firing. Together, these two effects may play a part in the pathogenesis of schizophrenia and other neuropsychiatric disorders.
Collapse
Affiliation(s)
- M J Miller
- Department of Physiology and Biophysics, Division of Human Genetics, University of California Irvine, Irvine, California 92697-4561, USA
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Antonarakis SE, Blouin JL, Lasseter VK, Gehrig C, Radhakrishna U, Nestadt G, Housman DE, Kazazian HH, Kalman K, Gutman G, Fantino E, Chandy KG, Gargus JJ, Pulver AE. Lack of linkage or association between schizophrenia and the polymorphic trinucleotide repeat within the KCNN3 gene on chromosome 1q21. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19990820)88:4<348::aid-ajmg11>3.0.co;2-n] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
36
|
Antonarakis SE, Blouin JL, Lasseter VK, Gehrig C, Radhakrishna U, Nestadt G, Housman DE, Kazazian HH, Kalman K, Gutman G, Fantino E, Chandy KG, Gargus JJ, Pulver AE. Lack of linkage or association between schizophrenia and the polymorphic trinucleotide repeat within the KCNN3 gene on chromosome 1q21. Am J Med Genet 1999; 88:348-51. [PMID: 10402501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
To determine the importance of a candidate gene KCNN3 (formerly named hSKCa3) in the susceptibility to schizophrenia, we have studied the genotypes of a (CAG)n polymorphism within this gene in the DNAs of the members of 54 multiplex families with this disease. Parametric and nonparametric linkage analysis did not provide evidence for linkage between KCNN3 (that we mapped to chromosome 1q21) and schizophrenia. Furthermore, we observed no difference in the distribution of the (CAG)n alleles between affected and normal individuals. These results do not support the hypothesis that larger KCNN3 alleles are preferentially associated with schizophrenia [Chandy et al. 1998 Mol Psychiatr 3:32-37] in individuals from multiply affected families.
Collapse
Affiliation(s)
- S E Antonarakis
- Division of Medical Genetics, Geneva University Medical School and Hospitals, Switzerland.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Dror V, Shamir E, Ghanshani S, Kimhi R, Swartz M, Barak Y, Weizman R, Avivi L, Litmanovitch T, Fantino E, Kalman K, Jones EG, Chandy KG, Gargus JJ, Gutman GA, Navon R. hKCa3/KCNN3 potassium channel gene: association of longer CAG repeats with schizophrenia in Israeli Ashkenazi Jews, expression in human tissues and localization to chromosome 1q21. Mol Psychiatry 1999; 4:254-60. [PMID: 10395215 DOI: 10.1038/sj.mp.4000508] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [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: 11/09/2022]
Abstract
We demonstrate a significant association between longer CAG repeats in the hKCa3/KCNN3 calcium-activated potassium channel gene and schizophrenia in Israeli Ashkenazi Jews. We genotyped alleles from 84 Israeli Jewish patients with schizophrenia and from 102 matched controls. The overall allele frequency distribution is significantly different in patients vs controls (P = 0.00017, Wilcoxon Rank Sum test), with patients showing greater lengths of the CAG repeat. Northern blots reveal substantial levels of approximately 9 kb and approximately 13 kb hKCa3/KCNN3transcripts in brain, striated muscle, spleen and lymph nodes. Within the brain, hKCa3/KCNN3transcripts are most abundantly expressed in the substantia nigra, lesser amounts are detected in the basal ganglia, amygdala, hippocampus and subthalamic nuclei, while little is seen in the cerebral cortex, cerebellum and thalamus. In situ hybridization reveals abundant hKCa3/KCNN3 message localized within the substantia nigra and ventral tegmental area, and along the distributions of dopaminergic neurons from these regions into the nigrostriatal and mesolimbic pathways. FISH analysis shows that hKCa3/KCNN3 is located on chromosome 1q21.
Collapse
Affiliation(s)
- V Dror
- Human Genetics Department, Sackler Faculty of Medicine, Tel-Aviv, Israel
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Mutations in ion channels have been found to cause a variety of mendelian genetic diseases, and polyglutamine repeat expansion is a newly recognized pathogenic mechanism that causes several rare, genetic, late-onset neurological syndromes. Polymorphic polyglutamine tracts are present in a recently described human, calcium-activated potassium channel, KCNN3 (also known as hKCa3), and alleles of this gene that contain longer repeats have been associated with schizophrenia. The physiological function of the channel is consistent with an etiological role in this disease; drugs designed to target this channel might therefore provide novel psychotherapeutics.
Collapse
Affiliation(s)
- J J Gargus
- Dept of Physiology and Biophysics, University of California, Irvine 92697-4560, USA.
| | | | | |
Collapse
|
39
|
Li T, Hu X, Chandy KG, Fantino E, Kalman K, Gutman G, Gargus JJ, Freeman B, Murray RM, Dawson E, Liu X, Bruinvels AT, Sham PC, Collier DA. Transmission disequilibrium analysis of a triplet repeat within the hKCa3 gene using family trios with schizophrenia. Biochem Biophys Res Commun 1998; 251:662-5. [PMID: 9792831 DOI: 10.1006/bbrc.1998.9484] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
hKCa3 is a neuronal small conductance calcium-activated potassium channel which contains a polyglutamine tract, encoded by a polymorphic CAG repeat in the gene. Since an association between longer alleles of the CAG repeat and schizophrenia has been reported, we performed haplotype-based haplotype relative risk (HHRR) and transmission disequilibrium (TDT) in 97 family trios with schizophrenia from SW China. We found no evidence for an excess of longer CAG repeats in the patients, and the ETDT test was not significant for either allele-wise (P = 0.31) or genotype-wise analysis (P = 0.18). However, there was a deficit of transmission of the (CAG)20 repeat allele to affected offspring when this allele was considered individually by TDT (P = 0.012; not corrected for multiple testing). These data do not support a role for larger alleles at the hKCa3 locus in psychosis in Chinese subjects.
Collapse
Affiliation(s)
- T Li
- Department of Psychological Medicine and Centre for Social, Genetic and Developmental Psychiatry, The Institute of Psychiatry, De Crespigny Park, Denmark Hill, SE5 8AF, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
The epidermal growth factor receptor (EGFR) plays a critical role in normal growth and its overexpression is associated with several types of cancer. To learn more about regulation of the expression of this important receptor, we investigated the role of the TAF(II)250 subunit of transcription factor IID in the transcription of the EGFR gene. The EGFR gene has a TATA-less promoter and TAF(II)250 has previously been shown to have an important regulatory role in such promoters. The study was performed in the ts13 hamster cell line which has a temperature-sensitive mutation in the CCG1 gene that encodes TAF(II)250. At the nonpermissive temperature, the transcription of a few cell cycle-dependent genes is depressed in ts13 cells while global RNA synthesis is unaffected. Using this model system, we found that EGFR promoter-driven luciferase expression in transiently transfected ts13 cells decreased 8, 25, and 50-fold after 12, 24, and 48 hours, respectively, at the nonpermissive temperature. The decrease was partially rescued by cotransfection with the wild-type CCG1 gene. The expression of endogenous EGFR also appeared to be regulated by TAF(II)250--the maximum binding capacity of ts13 cells for 125I-labeled EGF decreased approximately twofold when incubated for 2 days at the nonpermissive temperature. Placing these studies in the context of the current understanding of the TFIID transcription complex, we speculate that selective stimulation of EGFR gene transcription may be mediated by TAF(II)250 interaction with enhancer-bound activators and the basal transcription machinery.
Collapse
Affiliation(s)
- G A Vargas
- Department of Biological Chemistry, University of California Medical School, Irvine, USA
| | | | | | | | | |
Collapse
|
41
|
Ghanshani S, Coleman M, Gustavsson P, Wu AC, Gargus JJ, Gutman GA, Dahl N, Mohrenweiser H, Chandy KG. Human calcium-activated potassium channel gene KCNN4 maps to chromosome 19q13.2 in the region deleted in diamond-blackfan anemia. Genomics 1998; 51:160-1. [PMID: 9693050 DOI: 10.1006/geno.1998.5333] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- S Ghanshani
- Department of Physiology and Biophysics, University of California, Irvine, California, 92697, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Bowen T, Guy CA, Craddock N, Cardno AG, Williams NM, Spurlock G, Murphy KC, Jones LA, Gray M, Sanders RD, McCarthy G, Chandy KG, Fantino E, Kalman K, Gutman GA, Gargus JJ, Williams J, McGuffin P, Owen MJ, O'Donovan MC. Further support for an association between a polymorphic CAG repeat in the hKCa3 gene and schizophrenia. Mol Psychiatry 1998; 3:266-9. [PMID: 9672903 DOI: 10.1038/sj.mp.4000400] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A recent study has suggested that a polymorphism in the hKCa3 potassium channel may be associated with raised susceptibility to schizophrenia. Despite its modest statistical significance, the study is intriguing for two reasons. First, hKCa3 contains a polymorphic CAG repeat in its coding sequence, with large repeats more common in schizophrenics compared with controls. This is interesting in view of several repeat expansion detection (RED) studies that have reported an excess of large CAG repeats in psychotic probands. Second, the hKCa3 gene is a functional candidate gene because studies of antipsychotic and psychotogenic compounds suggest that glutamatergic systems modulated by SKCa channels may be important in schizophrenia pathogenesis. In the light of the above, we have tested the hypothesis of an association between schizophrenia and the hKCa3 CAG repeat polymorphism using a case control study design. Under the same model of analysis as the earlier study, schizophrenic probands had a higher frequency of alleles with greater than 19 repeats than controls (chi 2 = 2.820, P = 0.047, 1-tail). Our data therefore provide modest support for the hypothesis that polymorphism in the hKCa3 gene may contribute to susceptibility to schizophrenia.
Collapse
Affiliation(s)
- T Bowen
- University of Wales College of Medicine, Division of Psychological Medicine, Heath Park, Cardiff, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Chandy KG, Fantino E, Wittekindt O, Kalman K, Tong LL, Ho TH, Gutman GA, Crocq MA, Ganguli R, Nimgaonkar V, Morris-Rosendahl DJ, Gargus JJ. Isolation of a novel potassium channel gene hSKCa3 containing a polymorphic CAG repeat: a candidate for schizophrenia and bipolar disorder? Mol Psychiatry 1998; 3:32-7. [PMID: 9491810 DOI: 10.1038/sj.mp.4000353] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.0] [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: 02/06/2023]
Abstract
Many human hereditary neurodegenerative diseases are caused by expanded CAG repeats, and anonymous CAG expansions have also been described in schizophrenia and bipolar disorder. We have isolated and sequenced a novel human cDNA encoding a neuronal, small conductance calcium-activated potassium channel (hSKCa3) that contains two arrays of CAG trinucleotide repeats. The second CAG repeat in hSKCa3 is highly polymorphic in control individuals, with alleles ranging in size from 12 to 28 repeats. The overall allele frequency distribution is significantly different in patients with schizophrenia compared to ethnically matched controls (Wilcoxon Rank Sum test, P=0.024), with CAG repeats longer than the modal value being over-represented in patients (Fisher Exact test, P=0.0035). A similar, non-significant, trend is seen for patients with bipolar disorder. These results provide evidence for a possible association between longer alleles in the hSKCa3 gene and both of these neuropsychiatric diseases, and emphasize the need for more extensive studies of this new gene. Small conductance calcium-activated K+ channels play a critical role in determining the firing pattern of neurons. These polyglutamine repeats may modulate hSKCa3 channel function and neuronal excitability, and thereby increase disease risk when combined with other genetic and environmental effects.
Collapse
Affiliation(s)
- K G Chandy
- Department of Physiology and Biophysics, University of California, Irvine 92697, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Nguyen HB, Estacion M, Gargus JJ. Mutations causing achondroplasia and thanatophoric dysplasia alter bFGF-induced calcium signals in human diploid fibroblasts. Hum Mol Genet 1997; 6:681-8. [PMID: 9158142 DOI: 10.1093/hmg/6.5.681] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 02/04/2023] Open
Abstract
Mutations in the fibroblast growth factor receptor (FGFR) gene family recently have been shown to underlie several hereditary disorders of bone development, with specific FGFR3 mutations causing achondroplasia (Ach) and thanatophoric dysplasia (TD). However, for none of these mutations has the defect in receptor function been demonstrated directly and, therefore, for none has the pathophysiological mechanism of the disease been defined. Using our established techniques for single-cell ratiometric real-time calcium image analysis, we defined the nature of the basic fibroblast growth factor (bFGF)-induced calcium signal in human diploid fibroblasts, and, in blinded studies, have analyzed the bFGF-induced signals from 18 independent fibroblast cell lines, including multiple lines from patients with known mutant alleles of FGFR3 and syndromes of Ach or TD. Control cells responded with transient increases in intracellular calcium, with many cells showing oscillatory calcium waves. Homozygous Ach cell lines failed to signal, whereas heterozygous Ach lines responded nearly normally. We observed heterogeneous signals in TD heterozygotes: the unresponsive lines all turned out to carry TD1 alleles, whereas all responsive lines had TD2 alleles. Since FGFR1, 2 and 3 receptors are known to be expressed in fibroblasts, our results suggest that specific mutant FGFR3 alleles can function in a dosage-dependent dominant-negative fashion to inactivate FGFR signaling.
Collapse
Affiliation(s)
- H B Nguyen
- Department of Physiology and Biophysics, University of California, Irvine 92697-4560, USA
| | | | | |
Collapse
|
45
|
Vargas GA, Fantino E, George-Nascimento C, Gargus JJ, Haigler HT. Reduced epidermal growth factor receptor expression in hypohidrotic ectodermal dysplasia and Tabby mice. J Clin Invest 1996; 97:2426-32. [PMID: 8647934 PMCID: PMC507327 DOI: 10.1172/jci118689] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [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: 02/01/2023] Open
Abstract
Patients with hypohidrotic ectodermal dysplasia (HED) and Tabby (Ta) mice lack sweat glands and there is compelling evidence that these phenotypes are caused by mutations in the same highly conserved but unidentified X-linked gene. Previous studies showed that exogenous epidermal growth factor (EGF) reversed the Ta phenotype but the EGF status in HED patients has not been studied at all. Studies reported herein investigated the hypothesis that the EGF signaling pathway is involved in HED/Ta. Fibroblasts from HED patients had a two- to eightfold decrease in binding capacity for (125)I-labeled EGF, a decreased expression of the immunoreactive 170-kD EGF receptor (EGFR) protein, and a corresponding reduction in EGFR mRNA. Reduced expression of the EGFR also was observed in Ta fibroblasts and liver membranes. Other aspects of the EGF signaling pathway, including EGF concentration in urine and plasma, were normal in both HED patients and Ta mice. We propose that a decreased expression of the EGFR plays a causal role in the HED/Ta phenotype.
Collapse
Affiliation(s)
- G A Vargas
- Department of Biological Chemistry, University of California Medical School, Irvine, California 92715, USA
| | | | | | | | | |
Collapse
|
46
|
Abstract
The shellfish poison maitotoxin causes the irreversible opening of nonselective cation channels in mouse L cell fibroblasts, consistent with the action of this toxin in other cell types and the previously demonstrated existence of 28-pS voltage-insensitive nonselected cation channels that are activated by platelet-derived growth factor in these cells. Toxin-induced opening of these nonselective cation channels led to increases of intracellular calcium and secondary activation of calcium-activated potassium channel. These effects were completely dependent on influx of extracellular calcium, supporting the conclusion that the maitotoxin-activated nonselective cation channels are permeable to calcium as well as to sodium and potassium. The implication of this finding is that calcium signaling through this channel underlies its links into the growth factor response.
Collapse
Affiliation(s)
- M Estacion
- Department of Physiology and Biophysics, University of California, Irvine 92717, USA
| | | | | |
Collapse
|
47
|
Abstract
Murine fibroblasts have a 28 pS calcium- and voltage-insensitive NSC that becomes quiescent at G0 arrest and is rapidly and specifically activated by PDGF. Activation is produced by the discrete loss of long channel closures. The NSC can be rapidly and reversibly blocked with the NSAID flufenamic acid, through a prostaglandin-independent mechanism. The cell cycle (not viability) is blocked concomitantly with NSC block. A somatic cell mutant with altered NSC conductance has been isolated and used to clone the genomic locus of the channel. The mutant growth phenotype adds further support to the participation of NSC conductance in cell cycle control.
Collapse
Affiliation(s)
- J J Gargus
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322
| | | | | |
Collapse
|
48
|
Sands JM, Gargus JJ, Fröhlich O, Gunn RB, Kokko JP. Urinary concentrating ability in patients with Jk(a-b-) blood type who lack carrier-mediated urea transport. J Am Soc Nephrol 1992; 2:1689-96. [PMID: 1498276 DOI: 10.1681/asn.v2121689] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Water homeostasis is regulated in large part by the proper operation of the urinary concentrating mechanism. In the renal inner medulla, urea recycling from the inner medullary collecting duct to the inner medullary interstitium is thought to be essential for the production of a concentrated urine; however, it has not been possible to test this hypothesis in humans. Recently, a unique combination of genetic abnormalities has been described: absence of Kidd blood group antigens and absence of carrier-mediated urea transport in erythrocytes. Because animal studies indicate a similarity between urea transport in red blood cells and the nephron, it was postulated that patients without the Kidd antigen might lack facilitated urea transport in their kidneys. Hence, their ability to concentrate urine maximally was measured. Current models of nephron function would predict that in the complete absence of urea transport, the maximal concentrating ability would be around 800 to 900 mosM/kg H2O. Two homozygous patients had a moderate decrease in maximal concentrating ability (UosM,max = 819 mosM/kg H2O); a heterozygote also had some limitation. These studies raise the possibility that the erythrocyte urea transporter and the kidney urea transporter are encoded by a single gene (detected by the mutational loss of the Kidd antigen) and that a lack of facilitated urea transport impairs urea recycling in the kidney and, hence, maximal urinary concentrating ability.
Collapse
Affiliation(s)
- J M Sands
- Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | | | | | | | | |
Collapse
|
49
|
Jung F, Selvaraj S, Gargus JJ. Blockers of platelet-derived growth factor-activated nonselective cation channel inhibit cell proliferation. Am J Physiol 1992; 262:C1464-70. [PMID: 1377445 DOI: 10.1152/ajpcell.1992.262.6.c1464] [Citation(s) in RCA: 31] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In serum-deprived G(o)-arrested cells, the addition of serum or growth factors initiates a cascade of events that culminates in DNA synthesis and mitosis. Recently, we showed that in mouse L-M(TK-) fibroblasts a 28-pS nonselective cation channel (NS channel) becomes quiescent at G(o) arrest and rapidly active within seconds of platelet-derived growth factor (PDGF) or serum addition, placing this response very early in the postreceptor signaling cascade. However, lack of specific channel blockers hindered determination of whether channel activation was necessary for mitogenesis. Derivatives of N-phenylanthranilic acid (DCA) have been reported to block a pancreatic nonselective channel. Therefore, using single-channel analysis, we examined the effect of these agents on the L-M(TK-) NS channel. Flufenamic acid and mefenamic acid rapidly produced reversible channel block with an inhibitory constant (Ki) approximately 10 microM. Furthermore, the component of the macroscopic K+ efflux shown to be mediated by the NS channel was blocked with a similar Ki value. DCA effects on cell proliferation were tested by measuring cloning efficiency and growth rate. Both were inhibited over the range of concentration that affected channel activity, and a 50% inhibitory dose of 50-100 microM was determined. This observation further substantiates the hypothesis that NS channel activation forms a necessary component in the transduction of the mitogenic signal from the PDGF receptor.
Collapse
Affiliation(s)
- F Jung
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322
| | | | | |
Collapse
|
50
|
Rinaldo P, Welch RD, Previs SF, Schmidt-Sommerfeld E, Gargus JJ, O'Shea JJ, Zinn AB. Ethylmalonic/adipic aciduria: effects of oral medium-chain triglycerides, carnitine, and glycine on urinary excretion of organic acids, acylcarnitines, and acylglycines. Pediatr Res 1991; 30:216-21. [PMID: 1945558 DOI: 10.1203/00006450-199109000-00002] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [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: 12/29/2022]
Abstract
A 9-y-old girl with ethylmalonic/adipic aciduria was hospitalized to determine the possible therapeutic efficacy of oral carnitine and glycine supplementation. To provoke a mild metabolic stress, her diet was supplemented with 440 mg/kg/d of medium-chain triglycerides. She was treated successively with carnitine (100 mg/kg/d) for 5 d, neither carnitine nor glycine for 2 d, and then glycine (250 mg/kg/d) for 6 d. Consecutive 12-h urine collections were obtained throughout the entire period. The urinary excretion of eight organic acids, four acylglycines, and four acylcarnitines, which accumulate as a result of a metabolic block of five mitochondrial acyl-CoA dehydrogenases, were quantitatively determined by capillary gas chromatography, stable isotope dilution gas chromatography/mass spectrometry, and radioisotopic exchange HPLC, respectively. The excretion of each group of metabolites was calculated as the mean percentage of total output (mumol/24 h) during the four phases of the protocol (organic acids/acylglycines/acylcarnitines = 100.0%): 1) regular diet (3 d); 88.1/10.8/1.1; 2) medium-chain triglyceride supplementation (4); 82.5/15.6/1.9; 3) medium-chain triglycerides plus carnitine (5); 79.2/8.2/12.6; and 4) medium-chain triglycerides plus glycine (6); 81.0/18.7/0.3. Comparison between total and individual excretion of acylglycines and acylcarnitines indicates that oral glycine supplementation enhanced the conjugation and excretion of fatty acyl-CoA intermediates as efficiently as carnitine. We propose that oral glycine supplementation should be considered in the treatment of other inborn errors of metabolism associated with abnormal urinary excretion of acylglycines.
Collapse
Affiliation(s)
- P Rinaldo
- Department of Genetics, Yale University, New Haven, Connecticut 06510
| | | | | | | | | | | | | |
Collapse
|