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Brignone MS, Lanciotti A, Molinari P, Mallozzi C, De Nuccio C, Caprini ES, Petrucci TC, Visentin S, Ambrosini E. Megalencephalic leukoencephalopathy with subcortical cysts protein-1: A new calcium-sensitive protein functionally activated by endoplasmic reticulum calcium release and calmodulin binding in astrocytes. Neurobiol Dis 2024; 190:106388. [PMID: 38141856 DOI: 10.1016/j.nbd.2023.106388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 12/04/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023] Open
Abstract
BACKGROUND MLC1 is a membrane protein highly expressed in brain perivascular astrocytes and whose mutations account for the rare leukodystrophy (LD) megalencephalic leukoencephalopathy with subcortical cysts disease (MLC). MLC is characterized by macrocephaly, brain edema and cysts, myelin vacuolation and astrocyte swelling which cause cognitive and motor dysfunctions and epilepsy. In cultured astrocytes, lack of functional MLC1 disturbs cell volume regulation by affecting anion channel (VRAC) currents and the consequent regulatory volume decrease (RVD) occurring in response to osmotic changes. Moreover, MLC1 represses intracellular signaling molecules (EGFR, ERK1/2, NF-kB) inducing astrocyte activation and swelling following brain insults. Nevertheless, to date, MLC1 proper function and MLC molecular pathogenesis are still elusive. We recently reported that in astrocytes MLC1 phosphorylation by the Ca2+/Calmodulin-dependent kinase II (CaMKII) in response to intracellular Ca2+ release potentiates MLC1 activation of VRAC. These results highlighted the importance of Ca2+ signaling in the regulation of MLC1 functions, prompting us to further investigate the relationships between intracellular Ca2+ and MLC1 properties. METHODS We used U251 astrocytoma cells stably expressing wild-type (WT) or mutated MLC1, primary mouse astrocytes and mouse brain tissue, and applied biochemistry, molecular biology, video imaging and electrophysiology techniques. RESULTS We revealed that WT but not mutant MLC1 oligomerization and trafficking to the astrocyte plasma membrane is favored by Ca2+ release from endoplasmic reticulum (ER) but not by capacitive Ca2+ entry in response to ER depletion. We also clarified the molecular events underlining MLC1 response to cytoplasmic Ca2+ increase, demonstrating that, following Ca2+ release, MLC1 binds the Ca2+ effector protein calmodulin (CaM) at the carboxyl terminal where a CaM binding sequence was identified. Using a CaM inhibitor and generating U251 cells expressing MLC1 with CaM binding site mutations, we found that CaM regulates MLC1 assembly, trafficking and function, being RVD and MLC-linked signaling molecules abnormally regulated in these latter cells. CONCLUSION Overall, we qualified MLC1 as a Ca2+ sensitive protein involved in the control of volume changes in response to ER Ca2+ release and astrocyte activation. These findings provide new insights for the comprehension of the molecular mechanisms responsible for the myelin degeneration occurring in MLC and other LD where astrocytes have a primary role in the pathological process.
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Affiliation(s)
- M S Brignone
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - A Lanciotti
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - P Molinari
- Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - C Mallozzi
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - C De Nuccio
- Istituto Superiore di Sanità, Research Coordination and Support Service, Viale Regina Elena 299, 00161 Rome, Italy
| | - E S Caprini
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - T C Petrucci
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy
| | - S Visentin
- Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Viale Regina Elena 299, 00161 Rome, Italy
| | - E Ambrosini
- Istituto Superiore di Sanità, Department of Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy.
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Tabolacci E, Pomponi MG, Remondini L, Pietrobono R, Orteschi D, Nobile V, Pucci C, Musto E, Pane M, Mercuri EM, Neri G, Genuardi M, Chiurazzi P, Zollino M. Co-Occurrence of Fragile X Syndrome with a Second Genetic Condition: Three Independent Cases of Double Diagnosis. Genes (Basel) 2021; 12:genes12121909. [PMID: 34946857 PMCID: PMC8701878 DOI: 10.3390/genes12121909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/04/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and autism caused by the instability of a CGG trinucleotide repeat in exon 1 of the FMR1 gene. The co-occurrence of FXS with other genetic disorders has only been occasionally reported. Here, we describe three independent cases of FXS co-segregation with three different genetic conditions, consisting of Duchenne muscular dystrophy (DMD), PPP2R5D--related neurodevelopmental disorder, and 2p25.3 deletion. The co-occurrence of DMD and FXS has been reported only once in a young boy, while in an independent family two affected boys were described, the elder diagnosed with FXS and the younger with DMD. This represents the second case in which both conditions coexist in a 5-year-old boy, inherited from his heterozygous mother. The next double diagnosis had never been reported before: through exome sequencing, a girl with FXS who was of 7 years of age with macrocephaly and severe psychomotor delay was found to carry a de novo variant in the PPP2R5D gene. Finally, a maternally inherited 2p25.3 deletion associated with a decreased level of the MYT1L transcript, only in the patient, was observed in a 33-year-old FXS male with severe seizures compared to his mother and two sex- and age-matched controls. All of these patients represent very rare instances of genetic conditions with clinical features that can be modified by FXS and vice versa.
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Affiliation(s)
- Elisabetta Tabolacci
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
| | - Maria Grazia Pomponi
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
| | - Laura Remondini
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
| | - Roberta Pietrobono
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
| | - Daniela Orteschi
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
| | - Veronica Nobile
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
| | - Cecilia Pucci
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
| | - Elisa Musto
- Sezione di Neuropsichiatria Infantile, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (E.M.); (M.P.); (E.M.M.)
- Unità di Neuropsichiatria Infantile, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Marika Pane
- Sezione di Neuropsichiatria Infantile, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (E.M.); (M.P.); (E.M.M.)
- Unità di Neuropsichiatria Infantile, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Eugenio M. Mercuri
- Sezione di Neuropsichiatria Infantile, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (E.M.); (M.P.); (E.M.M.)
- Unità di Neuropsichiatria Infantile, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Giovanni Neri
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Maurizio Genuardi
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
| | - Pietro Chiurazzi
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
- Correspondence: ; Tel.: +39-06-30154606
| | - Marcella Zollino
- Sezione di Medicina Genomica, Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.); (G.N.); (M.G.); (M.Z.)
- UOC Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.G.P.); (L.R.); (R.P.); (D.O.)
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Drissen MMCM, Schieving JH, Schuurs-Hoeijmakers JHM, Vos JR, Hoogerbrugge N. Red flags for early recognition of adult patients with PTEN Hamartoma Tumour Syndrome. Eur J Med Genet 2021; 64:104364. [PMID: 34637944 DOI: 10.1016/j.ejmg.2021.104364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Abstract
Patients with PTEN Hamartoma Tumour Syndrome (PHTS) are at increased risk of developing cancer. Many adult PHTS patients are not recognized as such and do not receive the cancer surveillance they need. Our aim was to define phenotypic characteristics that can easily be assessed and manifest by early adulthood, and hence could serve as red flags (i.e. alerting signals) for early recognition of adult patients at high risk of PHTS. Phenotypic characteristics including macrocephaly, multinodular goitre (MNG), and oral features were examined in 81 paediatric and 86 adult PHTS patients by one of two medical experts during yearly surveillance visits at our Dutch PHTS expert centre between 1997 and 2020. MNG was defined as signs of thyroid nodules and/or goitre. Oral features included gingival hypertrophy, high palate (adults only) and oral papillomas. Based on the characteristics' prevalence in different age groups, combinations of phenotypic characteristics were defined and evaluated on their potential to recognize individuals with PHTS. Macrocephaly was present in 100% of paediatric and 67% of adult patients. The prevalence of MNG was ∼50% in paediatric and gradually increased to >90% in adult patients. Similar percentages were observed for any of the oral features. Scoring two out of three of these characteristics yielded a sensitivity of 100% (95%CI 94-100%) in adults. The presence of the combination macrocephaly, MNG, or multiple oral features could serve as a red flag for general practitioners, medical specialists, and dentists to consider further assessment of the diagnosis PHTS in adults. In this way, recognition of adult PHTS patients might be improved and cancer surveillance can be offered timely.
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Affiliation(s)
- Meggie M C M Drissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands; Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, the Netherlands
| | - Jolanda H Schieving
- Department of Paediatric Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Janet R Vos
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands; Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, the Netherlands
| | - Nicoline Hoogerbrugge
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands; Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands.
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Hawer H, Mendelsohn BA, Mayer K, Kung A, Malhotra A, Tuupanen S, Schleit J, Brinkmann U, Schaffrath R. Diphthamide-deficiency syndrome: a novel human developmental disorder and ribosomopathy. Eur J Hum Genet 2020; 28:1497-1508. [PMID: 32576952 PMCID: PMC7575589 DOI: 10.1038/s41431-020-0668-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/06/2020] [Accepted: 05/28/2020] [Indexed: 02/06/2023] Open
Abstract
We describe a novel type of ribosomopathy that is defined by deficiency in diphthamidylation of translation elongation factor 2. The ribosomopathy was identified by correlating phenotypes and biochemical properties of previously described patients with diphthamide biosynthesis gene 1 (DPH1) deficiencies with a new patient that carried inactivating mutations in both alleles of the human diphthamide biosynthesis gene 2 (DPH2). The human DPH1 syndrome is an autosomal recessive disorder associated with developmental delay, abnormal head circumference (microcephaly or macrocephaly), short stature, and congenital heart disease. It is defined by variants with reduced functionality of the DPH1 gene observed so far predominantly in consanguineous homozygous patients carrying identical mutant alleles of DPH1. Here we report a child with a very similar phenotype carrying biallelic variants of the human DPH2. The gene products DPH1 and DPH2 are components of a heterodimeric enzyme complex that mediates the first step of the posttranslational diphthamide modification on the nonredundant eukaryotic translation elongation factor 2 (eEF2). Diphthamide deficiency was shown to reduce the accuracy of ribosomal protein biosynthesis. Both DPH2 variants described here severely impair diphthamide biosynthesis as demonstrated in human and yeast cells. This is the first report of a patient carrying compound heterozygous DPH2 loss-of-function variants with a DPH1 syndrome-like phenotype and implicates diphthamide deficiency as the root cause of this patient's clinical phenotype as well as of DPH1-syndrome. These findings define "diphthamide-deficiency syndrome" as a special ribosomopathy due to reduced functionality of components of the cellular machinery for eEF2-diphthamide synthesis.
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Affiliation(s)
- Harmen Hawer
- Fachgebiet Mikrobiologie, Institut für Biologie, Universität Kassel, D-34132, Kassel, Hessen, Germany
| | | | - Klaus Mayer
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, D-82377, Penzberg, Bavaria, Germany
| | - Ann Kung
- Kaiser Permanente Oakland Medical Center, Oakland, CA, 94611, USA
| | - Amit Malhotra
- Kaiser Permanente Oakland Medical Center, Oakland, CA, 94611, USA
| | - Sari Tuupanen
- Blueprint Genetics Oy, Keilaranta 16 A-B, 02150, Espoo, Finland
| | | | - Ulrich Brinkmann
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, D-82377, Penzberg, Bavaria, Germany.
| | - Raffael Schaffrath
- Fachgebiet Mikrobiologie, Institut für Biologie, Universität Kassel, D-34132, Kassel, Hessen, Germany
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Klein SD, Nguyen DC, Bhakta V, Wong D, Chang VY, Davidson TB, Martinez-Agosto JA. Mutations in the sonic hedgehog pathway cause macrocephaly-associated conditions due to crosstalk to the PI3K/AKT/mTOR pathway. Am J Med Genet A 2019; 179:2517-2531. [PMID: 31639285 PMCID: PMC7346528 DOI: 10.1002/ajmg.a.61368] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 02/09/2019] [Revised: 06/12/2019] [Accepted: 09/09/2019] [Indexed: 12/26/2022]
Abstract
The hedgehog (Hh) pathway is highly conserved and required for embryonic patterning and determination. Mutations in the Hh pathway are observed in sporadic tumors as well as under syndromic conditions. Common to these syndromes are the findings of polydactyly/syndactyly and brain overgrowth. The latter is also a finding most commonly observed in the cases of mutations in the PI3K/AKT/mTOR pathway. We have identified novel Hh pathway mutations and structural copy number variations in individuals with somatic overgrowth, macrocephaly, dysmorphic facial features, and developmental delay, which phenotypically closely resemble patients with phosphatase and tensin homolog (PTEN) mutations. We hypothesized that brain overgrowth and phenotypic overlap with syndromic overgrowth syndromes in these cases may be due to crosstalk between the Hh and PI3K/AKT/mTOR pathways. To test this, we modeled disease-associated variants by generating PTCH1 and Suppressor of Fused (SUFU) heterozygote cell lines using the CRISPR/Cas9 system. These cells demonstrate activation of PI3K signaling and increased phosphorylation of its downstream target p4EBP1 as well as a distinct cellular phenotype. To further investigate the mechanism underlying this crosstalk, we treated human neural stem cells with sonic hedgehog (SHH) ligand and performed transcriptional analysis of components of the mTOR pathway. These studies identified decreased expression of a set of mTOR negative regulators, leading to its activation. We conclude that there is a significant crosstalk between the SHH and PI3K/AKT/mTOR. We propose that this crosstalk is responsible for why mutations in PTCH1 and SUFU lead to macrocephaly phenotypes similar to those observed in PTEN hamartoma and other overgrowth syndromes associated with mutations in PI3K/AKT/mTOR pathway genes.
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Affiliation(s)
- Steven D. Klein
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Dzung C. Nguyen
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Viraj Bhakta
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Derek Wong
- Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Vivian Y. Chang
- Division of Hematology-Oncology, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Tom B. Davidson
- Division of Hematology-Oncology, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Julian A. Martinez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
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Nielsen J, Fejgin K, Sotty F, Nielsen V, Mørk A, Christoffersen CT, Yavich L, Lauridsen JB, Clausen D, Larsen PH, Egebjerg J, Werge TM, Kallunki P, Christensen KV, Didriksen M. A mouse model of the schizophrenia-associated 1q21.1 microdeletion syndrome exhibits altered mesolimbic dopamine transmission. Transl Psychiatry 2017; 7:1261. [PMID: 29187755 PMCID: PMC5802512 DOI: 10.1038/s41398-017-0011-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/19/2017] [Accepted: 08/04/2017] [Indexed: 01/07/2023] Open
Abstract
1q21.1 hemizygous microdeletion is a copy number variant leading to eightfold increased risk of schizophrenia. In order to investigate biological alterations induced by this microdeletion, we generated a novel mouse model (Df(h1q21)/+) and characterized it in a broad test battery focusing on schizophrenia-related assays. Df(h1q21)/+ mice displayed increased hyperactivity in response to amphetamine challenge and increased sensitivity to the disruptive effects of amphetamine and phencyclidine hydrochloride (PCP) on prepulse inhibition. Probing of the direct dopamine (DA) pathway using the DA D1 receptor agonist SKF-81297 revealed no differences in induced locomotor activity compared to wild-type mice, but Df(h1q21)/+ mice showed increased sensitivity to the DA D2 receptor agonist quinpirole and the D1/D2 agonist apomorphine. Electrophysiological characterization of DA neuron firing in the ventral tegmental area revealed more spontaneously active DA neurons and increased firing variability in Df(h1q21)/+ mice, and decreased feedback reduction of DA neuron firing in response to amphetamine. In a range of other assays, Df(h1q21)/+ mice showed no difference from wild-type mice: gross brain morphology and basic functions such as reflexes, ASR, thermal pain sensitivity, and motor performance were unaltered. Similarly, anxiety related measures, baseline prepulse inhibition, and seizure threshold were unaltered. In addition to the central nervous system-related phenotypes, Df(h1q21)/+ mice exhibited reduced head-to tail length, which is reminiscent of the short stature reported in humans with 1q21.1 deletion. With aspects of both construct and face validity, the Df(h1q21)/+ model may be used to gain insight into schizophrenia-relevant alterations in dopaminergic transmission.
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MESH Headings
- Abnormalities, Multiple/metabolism
- Abnormalities, Multiple/pathology
- Abnormalities, Multiple/physiopathology
- Amphetamine/pharmacology
- Animals
- Apomorphine/pharmacology
- Behavior, Animal/drug effects
- Benzazepines/pharmacology
- Chromosome Deletion
- Chromosomes, Human, Pair 1/metabolism
- Disease Models, Animal
- Dopamine Agonists/administration & dosage
- Dopamine Agonists/pharmacology
- Dopamine Uptake Inhibitors/administration & dosage
- Dopamine Uptake Inhibitors/pharmacology
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Excitatory Amino Acid Antagonists/administration & dosage
- Excitatory Amino Acid Antagonists/pharmacology
- Megalencephaly/metabolism
- Megalencephaly/pathology
- Megalencephaly/physiopathology
- Mice
- Mice, Inbred C57BL
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/metabolism
- Phencyclidine/pharmacology
- Phenotype
- Prepulse Inhibition/drug effects
- Quinpirole/pharmacology
- Receptors, Dopamine/drug effects
- Receptors, Dopamine/metabolism
- Schizophrenia/metabolism
- Schizophrenia/pathology
- Schizophrenia/physiopathology
- Ventral Tegmental Area/drug effects
- Ventral Tegmental Area/metabolism
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Affiliation(s)
- Jacob Nielsen
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark.
| | - Kim Fejgin
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | - Florence Sotty
- Division of Neurodegeneration, H. Lundbeck A/S, Valby, Denmark
| | - Vibeke Nielsen
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | - Arne Mørk
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | | | - Leonid Yavich
- Invilog Research Ltd and School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Jes B Lauridsen
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | - Dorte Clausen
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | - Peter H Larsen
- Division of Synaptic Transmission, H. Lundbeck A/S, Valby, Denmark
| | - Jan Egebjerg
- Division of Neurodegeneration, H. Lundbeck A/S, Valby, Denmark
| | - Thomas M Werge
- Institute of Biological Psychiatry, Mental Health Services of Copenhagen, University of Copenhagen & The Lundbeck Foundation's IPSYCH Initiative, Copenhagen, Denmark
| | - Pekka Kallunki
- Division of Neurodegeneration, H. Lundbeck A/S, Valby, Denmark
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7
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Leiter SM, Parker VER, Welters A, Knox R, Rocha N, Clark G, Payne F, Lotta L, Harris J, Guerrero-Fernández J, González-Casado I, García-Miñaur S, Gordo G, Wareham N, Martínez-Glez V, Allison M, O’Rahilly S, Barroso I, Meissner T, Davies S, Hussain K, Temple K, Barreda-Bonis AC, Kummer S, Semple RK. Hypoinsulinaemic, hypoketotic hypoglycaemia due to mosaic genetic activation of PI3-kinase. Eur J Endocrinol 2017; 177:175-186. [PMID: 28566443 PMCID: PMC5488397 DOI: 10.1530/eje-17-0132] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/16/2017] [Accepted: 05/30/2017] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Genetic activation of the insulin signal-transducing kinase AKT2 causes syndromic hypoketotic hypoglycaemia without elevated insulin. Mosaic activating mutations in class 1A phospatidylinositol-3-kinase (PI3K), upstream from AKT2 in insulin signalling, are known to cause segmental overgrowth, but the metabolic consequences have not been systematically reported. We assess the metabolic phenotype of 22 patients with mosaic activating mutations affecting PI3K, thereby providing new insight into the metabolic function of this complex node in insulin signal transduction. METHODS Three patients with megalencephaly, diffuse asymmetric overgrowth, hypoketotic, hypoinsulinaemic hypoglycaemia and no AKT2 mutation underwent further genetic, clinical and metabolic investigation. Signalling in dermal fibroblasts from one patient and efficacy of the mTOR inhibitor Sirolimus on pathway activation were examined. Finally, the metabolic profile of a cohort of 19 further patients with mosaic activating mutations in PI3K was assessed. RESULTS In the first three patients, mosaic mutations in PIK3CA (p.Gly118Asp or p.Glu726Lys) or PIK3R2 (p.Gly373Arg) were found. In different tissue samples available from one patient, the PIK3CA p.Glu726Lys mutation was present at burdens from 24% to 42%, with the highest level in the liver. Dermal fibroblasts showed increased basal AKT phosphorylation which was potently suppressed by Sirolimus. Nineteen further patients with mosaic mutations in PIK3CA had neither clinical nor biochemical evidence of hypoglycaemia. CONCLUSIONS Mosaic mutations activating class 1A PI3K cause severe non-ketotic hypoglycaemia in a subset of patients, with the metabolic phenotype presumably related to the extent of mosaicism within the liver. mTOR or PI3K inhibitors offer the prospect for future therapy.
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Affiliation(s)
- Sarah M Leiter
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | - Victoria E R Parker
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | - Alena Welters
- Department of General PaediatricsNeonatology and Paediatric Cardiology, University Children’s Hospital, Düsseldorf, Germany
| | - Rachel Knox
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | - Nuno Rocha
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | - Graeme Clark
- Department of Molecular GeneticsAddenbrooke’s Hospital, Cambridge, UK
| | | | - Luca Lotta
- MRC Epidemiology UnitUniversity of Cambridge, Cambridge, UK
| | - Julie Harris
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | | | | | - Sixto García-Miñaur
- Departments of Clinical and Molecular GeneticsLa Paz Hospital, Madrid, Spain
| | - Gema Gordo
- Departments of Clinical and Molecular GeneticsLa Paz Hospital, Madrid, Spain
| | - Nick Wareham
- MRC Epidemiology UnitUniversity of Cambridge, Cambridge, UK
| | | | | | - Stephen O’Rahilly
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
| | - Inês Barroso
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
- Wellcome Trust Sanger InstituteHinxton, Cambridge, UK
| | - Thomas Meissner
- Department of General PaediatricsNeonatology and Paediatric Cardiology, University Children’s Hospital, Düsseldorf, Germany
| | - Susan Davies
- Departments of HistopathologyAddenbrooke’s Hospital, Cambridge, UK
| | - Khalid Hussain
- Institute of Child HealthUniversity College London, London, UK
| | - Karen Temple
- Department of Clinical GeneticsUniversity Hospital Southampton, Southampton, UK
| | | | - Sebastian Kummer
- Department of General PaediatricsNeonatology and Paediatric Cardiology, University Children’s Hospital, Düsseldorf, Germany
| | - Robert K Semple
- Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- The National Institute for Health ResearchCambridge Biomedical Research Centre, Cambridge, UK
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Pavone P, Praticò AD, Rizzo R, Corsello G, Ruggieri M, Parano E, Falsaperla R. A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment. Medicine (Baltimore) 2017; 96:e6814. [PMID: 28658095 PMCID: PMC5500017 DOI: 10.1097/md.0000000000006814] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 11/26/2022] Open
Abstract
Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associated with megalencephaly are classically defined into 3 groups: idiopathic or benign, metabolic, and anatomic. In this article, we seek to underline the clinical aspect of megalencephaly, emphasizing the main disorders that manifest with this anomaly in an attempt to properly categorize these disorders within the megalencephaly group.
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Affiliation(s)
- Piero Pavone
- University-Hospital “Policlinico-Vittorio Emanuele”
| | - Andrea Domenico Praticò
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Renata Rizzo
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
| | - Giovanni Corsello
- Department of Maternal and Child Health, University of Palermo, Palermo
| | - Martino Ruggieri
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry
| | - Enrico Parano
- National Research Council, Section of Catania, Catania, Italy
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9
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Webb TR, Matarin M, Gardner JC, Kelberman D, Hassan H, Ang W, Michaelides M, Ruddle JB, Pennell CE, Yazar S, Khor CC, Aung T, Yogarajah M, Robson AG, Holder GE, Cheetham ME, Traboulsi EI, Moore AT, Sowden JC, Sisodiya SM, Mackey DA, Tuft SJ, Hardcastle AJ. X-linked megalocornea caused by mutations in CHRDL1 identifies an essential role for ventroptin in anterior segment development. Am J Hum Genet 2012; 90:247-59. [PMID: 22284829 DOI: 10.1016/j.ajhg.2011.12.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [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: 11/02/2011] [Revised: 12/07/2011] [Accepted: 12/26/2011] [Indexed: 01/30/2023] Open
Abstract
X-linked megalocornea (MGC1) is an ocular anterior segment disorder characterized by an increased cornea diameter and deep anterior chamber evident at birth and later onset of mosaic corneal degeneration (shagreen), arcus juvenilis, and presenile cataracts. We identified copy-number variation, frameshift, missense, splice-site and nonsense mutations in the Chordin-like 1 gene (CHRDL1) on Xq23 as the cause of the condition in seven MGC1 families. CHRDL1 encodes ventroptin, a bone morphogenic protein antagonist with a proposed role in specification of topographic retinotectal projections. Electrophysiological evaluation revealed mild generalized cone system dysfunction and, in one patient, an interhemispheric asymmetry in visual evoked potentials. We show that CHRDL1 is expressed in the developing human cornea and anterior segment in addition to the retina. We explored the impact of loss of ventroptin function on brain function and morphology in vivo. CHRDL1 is differentially expressed in the human fetal brain, and there is high expression in cerebellum and neocortex. We show that MGC1 patients have a superior cognitive ability despite a striking focal loss of myelination of white matter. Our findings reveal an unexpected requirement for ventroptin during anterior segment development and the consequences of a lack of function in the retina and brain.
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Affiliation(s)
- Tom R Webb
- Institute of Ophthalmology, University College London, UK
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