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Ganapathi M, Friocourt G, Gueguen N, Friederich MW, Le Gac G, Okur V, Loaëc N, Ludwig T, Ka C, Tanji K, Marcorelles P, Theodorou E, Lignelli-Dipple A, Voisset C, Walker MA, Briere LC, Bourhis A, Blondel M, LeDuc C, Hagen J, Cooper C, Muraresku C, Ferec C, Garenne A, Lelez-Soquet S, Rogers CA, Shen Y, Strode DK, Bizargity P, Iglesias A, Goldstein A, High FA, Network UD, Sweetser DA, Ganetzky R, Van Hove JLK, Procaccio V, Le Marechal C, Chung WK. A homozygous splice variant in ATP5PO, disrupts mitochondrial complex V function and causes Leigh syndrome in two unrelated families. J Inherit Metab Dis 2022; 45:996-1012. [PMID: 35621276 PMCID: PMC9474623 DOI: 10.1002/jimd.12526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 11/10/2022]
Abstract
Mitochondrial complex V plays an important role in oxidative phosphorylation by catalyzing the generation of ATP. Most complex V subunits are nuclear encoded and not yet associated with recognized Mendelian disorders. Using exome sequencing, we identified a rare homozygous splice variant (c.87+3A>G) in ATP5PO, the complex V subunit which encodes the oligomycin sensitivity conferring protein, in three individuals from two unrelated families, with clinical suspicion of a mitochondrial disorder. These individuals had a similar, severe infantile and often lethal multi-systemic disorder that included hypotonia, developmental delay, hypertrophic cardiomyopathy, progressive epileptic encephalopathy, progressive cerebral atrophy, and white matter abnormalities on brain MRI consistent with Leigh syndrome. cDNA studies showed a predominant shortened transcript with skipping of exon 2 and low levels of the normal full-length transcript. Fibroblasts from the affected individuals demonstrated decreased ATP5PO protein, defective assembly of complex V with markedly reduced amounts of peripheral stalk proteins, and complex V hydrolytic activity. Further, expression of human ATP5PO cDNA without exon 2 (hATP5PO-∆ex2) in yeast cells deleted for yATP5 (ATP5PO homolog) was unable to rescue growth on media which requires oxidative phosphorylation when compared to the wild type construct (hATP5PO-WT), indicating that exon 2 deletion leads to a non-functional protein. Collectively, our findings support the pathogenicity of the ATP5PO c.87+3A>G variant, which significantly reduces but does not eliminate complex V activity. These data along with the recent report of an affected individual with ATP5PO variants, add to the evidence that rare biallelic variants in ATP5PO result in defective complex V assembly, function and are associated with Leigh syndrome.
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Affiliation(s)
- Mythily Ganapathi
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| | | | - Naig Gueguen
- MitoLab, UMR CNRS 6015 - INSERM U1083, MitoVasc Institute, Angers University Hospital, Angers, France
| | - Marisa W Friederich
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, Colorado, USA
- Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, Aurora, Colorado, USA
| | - Gerald Le Gac
- Univ Brest, Inserm, EFS, UMR1078, France
- CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, France
| | - Volkan Okur
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | | | - Thomas Ludwig
- Univ Brest, Inserm, EFS, UMR1078, France
- CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, France
| | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR1078, France
- CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, France
| | - Kurenai Tanji
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - Pascale Marcorelles
- CHRU de Brest, Service d'anatomie cytologie pathologie, CHU et centre de référence des maladies neuromusculaires, Brest, France
| | - Evangelos Theodorou
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Division of Medical Genetics & Metabolism, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Angela Lignelli-Dipple
- Department of Radiology, Columbia University Irving Medical Center, New York, New York, USA
| | | | - Melissa A Walker
- Division of Neurogenetics, Child Neurology, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Lauren C Briere
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Amélie Bourhis
- CHRU de Brest, Service d'anatomie cytologie pathologie, CHU et centre de référence des maladies neuromusculaires, Brest, France
| | | | - Charles LeDuc
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Jacob Hagen
- Department of Biomedical Sciences, Columbia University Irving Medical Center, New York, New York, USA
| | - Cathleen Cooper
- Department of Radiology, Columbia University Irving Medical Center, New York, New York, USA
| | - Colleen Muraresku
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | | | | | - Cassandra A Rogers
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Yufeng Shen
- Department of Biomedical Sciences, Columbia University Irving Medical Center, New York, New York, USA
| | - Dana K Strode
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, Colorado, USA
| | - Peyman Bizargity
- Division of Medical Genetics, Cohen Children's Medical Center, New York, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, New York, USA
| | - Alejandro Iglesias
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Amy Goldstein
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Frances A High
- Division of Medical Genetics & Metabolism, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | | - David A Sweetser
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
- Division of Medical Genetics & Metabolism, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Rebecca Ganetzky
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Johan L K Van Hove
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, Colorado, USA
- Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, Aurora, Colorado, USA
| | - Vincent Procaccio
- MitoLab, UMR CNRS 6015 - INSERM U1083, MitoVasc Institute, Angers University Hospital, Angers, France
| | - Cedric Le Marechal
- Univ Brest, Inserm, EFS, UMR1078, France
- CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, France
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
- Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA
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Zuhra K, Panagaki T, Randi EB, Augsburger F, Blondel M, Friocourt G, Herault Y, Szabo C. Mechanism of cystathionine-β-synthase inhibition by disulfiram: The role of bis(N,N-diethyldithiocarbamate)-copper(II). Biochem Pharmacol 2020; 182:114267. [PMID: 33035509 DOI: 10.1016/j.bcp.2020.114267] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Hydrogen sulfide (H2S) is an endogenous mammalian gasotransmitter. Cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) are the principal enzymes responsible for its biogenesis. A recent yeast screen suggested that disulfiram (a well-known inhibitor of aldehyde dehydrogenase and a clinically used drug in the treatment of alcoholism) may inhibit CBS in a cell-based environment. However, prior studies have not observed any direct inhibition of CBS by disulfiram. We investigated the potential role of bioconversion of disulfiram to bis(N,N-diethyldithiocarbamate)-copper(II) complex (CuDDC) in the inhibitory effect of disulfiram on H2S production and assessed its effect in two human cell types with high CBS expression: HCT116 colon cancer cells and Down syndrome (DS) fibroblasts. METHODS H2S production from recombinant human CBS, CSE and 3-MST was measured using the fluorescent H2S probe AzMC. Mouse liver homogenate (a rich source of CBS) was also employed to measure H2S biosynthesis. The interaction of copper with accessible protein cysteine residues was evaluated using the DTNB method. Cell proliferation and viability were measured using the BrdU and MTT methods. Cellular bioenergetics was evaluated by Extracellular Flux Analysis. RESULTS While disulfiram did not exert any significant direct inhibitory effect on any of the H2S-producing enzymes, its metabolite, CuDDC was a potent inhibitor of CBS and CSE. The mode of its action is likely related to the complexed copper molecule. In cell-based systems, the effects of disulfiram were variable. In colon cancer cells, no significant effect of disulfiram was observed on H2S production or proliferation or viability. In contrast, in DS fibroblasts, disulfiram inhibited H2S production and improved proliferation and viability. Copper, on its own, failed to have any effects on either cell type, likely due to its low cell penetration. CuDDC inhibited H2S production in both cell types studied and exerted the functional effects that would be expected from a CBS inhibitor: inhibition of cell proliferation of cancer cells and a bell-shaped effect (stimulation of proliferation at low concentration and inhibition of these responses at higher concentration) in DS cells. Control experiments using a chemical H2S donor showed that, in addition to inhibiting CBS and CSE, part of the biological effects of CuDDC relates to a direct reaction with H2S, which occurs through its complexed copper. CONCLUSIONS Disulfiram, via its metabolite CuDDC acts as an inhibitor of CBS and a scavenger of H2S, which, in turn, potently suppresses H2S levels in various cell types. Inhibition of H2S biosynthesis may explain some of the previously reported actions of disulfiram and CuDDC in vitro and in vivo. Disulfiram or CuDDC may be considered as potential agents for the experimental therapy of various pathophysiological conditions associated with H2S overproduction.
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Affiliation(s)
- Karim Zuhra
- Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Theodora Panagaki
- Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Elisa B Randi
- Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Fiona Augsburger
- Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Marc Blondel
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Gaelle Friocourt
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Yann Herault
- Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 1 Rue Laurent Fries, 67404 Illkirch, France
| | - Csaba Szabo
- Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
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Marechal D, Brault V, Leon A, Martin D, Lopes Pereira P, Loaëc N, Birling MC, Friocourt G, Blondel M, Herault Y. Cbs overdosage is necessary and sufficient to induce cognitive phenotypes in mouse models of Down syndrome and interacts genetically with Dyrk1a. Hum Mol Genet 2019; 28:1561-1577. [PMID: 30649339 DOI: 10.1093/hmg/ddy447] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 01/16/2023] Open
Abstract
Identifying dosage-sensitive genes is a key to understand the mechanisms underlying intellectual disability in Down syndrome (DS). The Dp(17Abcg1-Cbs)1Yah DS mouse model (Dp1Yah) shows cognitive phenotypes that need to be investigated to identify the main genetic driver. Here, we report that three copies of the cystathionine-beta-synthase gene (Cbs) in the Dp1Yah mice are necessary to observe a deficit in the novel object recognition (NOR) paradigm. Moreover, the overexpression of Cbs alone is sufficient to induce deficits in the NOR test. Accordingly, overexpressing human CBS specifically in Camk2a-expressing neurons leads to impaired objects discrimination. Altogether, this shows that Cbs overdosage is involved in DS learning and memory phenotypes. To go further, we identified compounds that interfere with the phenotypical consequence of CBS overdosage in yeast. Pharmacological intervention in Tg(CBS) mice with one selected compound restored memory in the NOR test. In addition, using a genetic approach, we demonstrated an epistatic interaction between Cbs and Dyrk1a, another human chromosome 21-located gene (which encodes the dual-specificity tyrosine phosphorylation-regulated kinase 1a) and an already known target for DS therapeutic intervention. Further analysis using proteomic approaches highlighted several molecular pathways, including synaptic transmission, cell projection morphogenesis and actin cytoskeleton, that are affected by DYRK1A and CBS overexpression. Overall, we demonstrated that CBS overdosage underpins the DS-related recognition memory deficit and that both CBS and DYRK1A interact to control accurate memory processes in DS. In addition, our study establishes CBS as an intervention point for treating intellectual deficiencies linked to DS.
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Affiliation(s)
- Damien Marechal
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Véronique Brault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Alice Leon
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Dehren Martin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Patricia Lopes Pereira
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, 3B Rue de la Férollerie Orléans, France
| | - Nadege Loaëc
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | | | - Gaelle Friocourt
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Marc Blondel
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Yann Herault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, Illkirch, France
- Université de Strasbourg, Illkirch, France
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, ICS, Illkirch, France
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Panozzo C, Laleve A, Tribouillard-Tanvier D, Ostojić J, Sellem CH, Friocourt G, Bourand-Plantefol A, Burg A, Delahodde A, Blondel M, Dujardin G. Chemicals or mutations that target mitochondrial translation can rescue the respiratory deficiency of yeast bcs1 mutants. Biochim Biophys Acta Mol Cell Res 2017; 1864:2297-2307. [PMID: 28888990 DOI: 10.1016/j.bbamcr.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 11/28/2022]
Abstract
Bcs1p is a chaperone that is required for the incorporation of the Rieske subunit within complex III of the mitochondrial respiratory chain. Mutations in the human gene BCS1L (BCS1-like) are the most frequent nuclear mutations resulting in complex III-related pathologies. In yeast, the mimicking of some pathogenic mutations causes a respiratory deficiency. We have screened chemical libraries and found that two antibiotics, pentamidine and clarithromycin, can compensate two bcs1 point mutations in yeast, one of which is the equivalent of a mutation found in a human patient. As both antibiotics target the large mtrRNA of the mitoribosome, we focused our analysis on mitochondrial translation. We found that the absence of non-essential translation factors Rrf1 or Mif3, which act at the recycling/initiation steps, also compensates for the respiratory deficiency of yeast bcs1 mutations. At compensating concentrations, both antibiotics, as well as the absence of Rrf1, cause an imbalanced synthesis of respiratory subunits which impairs the assembly of the respiratory complexes and especially that of complex IV. Finally, we show that pentamidine also decreases the assembly of complex I in nematode mitochondria. It is well known that complexes III and IV exist within the mitochondrial inner membrane as supramolecular complexes III2/IV in yeast or I/III2/IV in higher eukaryotes. Therefore, we propose that the changes in mitochondrial translation caused by the drugs or by the absence of translation factors, can compensate for bcs1 mutations by modifying the equilibrium between illegitimate, and thus inactive, and active supercomplexes.
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Affiliation(s)
- C Panozzo
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Laleve
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - D Tribouillard-Tanvier
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - J Ostojić
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - C H Sellem
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - G Friocourt
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Bourand-Plantefol
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Burg
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Delahodde
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - M Blondel
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - G Dujardin
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France.
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Mattiske T, Lee K, Gecz J, Friocourt G, Shoubridge C. Embryonic forebrain transcriptome of mice with polyalanine expansion mutations in the ARX homeobox gene. Hum Mol Genet 2017; 25:5433-5443. [PMID: 27798109 DOI: 10.1093/hmg/ddw360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/18/2016] [Indexed: 11/14/2022] Open
Abstract
The Aristaless-related homeobox (ARX) gene encodes a paired-type homeodomain transcription factor with critical roles in embryonic development. Mutations in ARX give rise to intellectual disability (ID), epilepsy and brain malformation syndromes. To capture the genetics and molecular disruptions that underpin the ARX-associated clinical phenotypes, we undertook a transcriptome wide RNASeq approach to analyse developing (12.5 dpc) telencephalon of mice modelling two recurrent polyalanine expansion mutations with different phenotypic severities in the ARX gene. Here we report 238 genes significantly deregulated (Log2FC > +/-1.1, P-value <0.05) when both mutations are compared to wild-type (WT) animals. When each mutation is considered separately, a greater number of genes were deregulated in the severe PA1 mice (825) than in the PA2 animals (78). Analysing genes deregulated in either or both mutant strains, we identified 12% as implicated in ID, epilepsy and autism (99/858), with ∼5% of them as putative or known direct targets of ARX transcriptional regulation. We propose a core pathway of transcription regulators, including Hdac4, involved in chromatin condensation and transcriptional repression, and one of its targets, the transcription factor Twist1, as potential drivers of the ID and infantile spasms in patients with ARX polyalanine expansion mutations. We predict that the subsequent disturbance to this pathway is a consequence of ARX protein reduction with a broader and more significant level of disruption in the PA1 in comparison to the PA2 mice. Identifying early triggers of ARX-associated phenotypes contributes to our understanding of particular clusters/pathways underpinning comorbid phenotypes that are shared by many neurodevelopmental disorders.
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Affiliation(s)
- Tessa Mattiske
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Kristie Lee
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Jozef Gecz
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Gaelle Friocourt
- Inserm, UMR1078, Brest, France.,Brest University, Faculté de Médecine et des Sciences de la Santé, Sfr ScInBioS, Brest, France
| | - Cheryl Shoubridge
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
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Bahi N, Friocourt G, Carrié A, Graham ME, Weiss JL, Chafey P, Fauchereau F, Burgoyne RD, Chelly J. IL1 receptor accessory protein like, a protein involved in X-linked mental retardation, interacts with Neuronal Calcium Sensor-1 and regulates exocytosis. Hum Mol Genet 2003; 12:1415-25. [PMID: 12783849 DOI: 10.1093/hmg/ddg147] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previously, human genetics-based approaches allowed us to show that mutations in the IL-1 receptor accessory protein-like gene (IL1RAPL) are responsible for a non-specific form of X-linked mental retardation. This gene encodes a predicted protein of 696 amino acids that belongs to a novel class of the IL-1/Toll receptor family. In addition to the extracellular portion consisting of three Ig-like domains and the intracellular TIR domain characteristic of the IL-1/Toll receptor family, IL1RAPL contains a specific 150 amino acid carboxy terminus that has no significant homology with any protein of known function. In order to begin to elucidate the function of this IL-1/Toll receptor-like protein, we have assessed the effect of recombinant IL1RAPL on the binding affinity of type I IL-1R for its ligands IL-1alpha and beta and searched for proteins interacting with the specific carboxy terminus domain of IL1RAPL. Our results show that IL1RAPL is not a protein receptor for IL-1. In addition we present here the identification of Neuronal Calcium Sensor-1 (NCS-1) as an IL1RAPL interactor. Remarkably, although NCS-1 and its non-mammalian homologue, frequenin, are members of a highly conserved EF-hand Ca(2+) binding protein family, our data show that IL1RAPL interacts only with NCS-1 through its specific C-terminal domain. The functional relevance of IL1RAPL activity was further supported by the inhibitory effect on exocytosis in PC12 cells overexpressing IL1RAPL. Taken together, our data suggest that IL1RAPL may regulate calcium-dependent exocytosis and provide insight into the understanding of physiopathological mechanisms underlying cognitive impairment resulting from IL1RAPL dysfunction.
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Affiliation(s)
- Nadia Bahi
- Institut Cochin, INSERM Unité 567, CNRS UMR 8104, Université Paris V, CHU Cochin, 24 rue du Faubourg Saint Jacques, 75 014 Paris, France
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Benchoua A, Couriaud C, Guégan C, Tartier L, Couvert P, Friocourt G, Chelly J, Ménissier-de Murcia J, Onténiente B. Active caspase-8 translocates into the nucleus of apoptotic cells to inactivate poly(ADP-ribose) polymerase-2. J Biol Chem 2002; 277:34217-22. [PMID: 12065591 DOI: 10.1074/jbc.m203941200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [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: 11/06/2022] Open
Abstract
Caspase-8 is the prototypic initiator of the death domain receptor pathway of apoptosis. Here, we report that caspase-8 not only triggers and amplifies the apoptotic process at cytoplasmic sites but can also act as an executioner at nuclear levels. In a murine model of acute ischemia, caspase-8 is relocated into the nucleus of apoptotic neurons, where it cleaves PARP-2, a member of the poly(ADP-ribose) polymerase family involved in DNA repair. As indicated by site-directed mutagenesis, PARP-2 cleavage occurs preferentially at the LQMD sequence mapped between the DNA binding and the catalytic domains of the protein. This is close to the cleavage sequence found in Bid, the cytoplasmic target of caspase-8. Activity assays confirm that cleavage of PARP-2 results in inactivation of its poly(ADP-ribosylation) property, proportional to the efficiency of the cleavage. Our findings add to the complexity of proteolytic caspase networks by demonstrating that caspase-8 is in turn an initiator, amplifier, and effector caspase.
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Affiliation(s)
- Alexandra Benchoua
- INSERM U 421, Université Paris Val-de-Marne, 8 rue du General Sarrail, F-94010 Créteil cedex, France
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8
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Bienvenu T, Poirier K, Friocourt G, Bahi N, Beaumont D, Fauchereau F, Ben Jeema L, Zemni R, Vinet MC, Francis F, Couvert P, Gomot M, Moraine C, van Bokhoven H, Kalscheuer V, Frints S, Gecz J, Ohzaki K, Chaabouni H, Fryns JP, Desportes V, Beldjord C, Chelly J. ARX, a novel Prd-class-homeobox gene highly expressed in the telencephalon, is mutated in X-linked mental retardation. Hum Mol Genet 2002; 11:981-91. [PMID: 11971879 DOI: 10.1093/hmg/11.8.981] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.8] [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: 11/12/2022] Open
Abstract
Investigation of a critical region for an X-linked mental retardation (XLMR) locus led us to identify a novel Aristaless related homeobox gene (ARX ). Inherited and de novo ARX mutations, including missense mutations and in frame duplications/insertions leading to expansions of polyalanine tracts in ARX, were found in nine familial and one sporadic case of MR. In contrast to other genes involved in XLMR, ARX expression is specific to the telencephalon and ventral thalamus. Notably there is an absence of expression in the cerebellum throughout development and also in adult. The absence of detectable brain malformations in patients suggests that ARX may have an essential role, in mature neurons, required for the development of cognitive abilities.
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9
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Friocourt G, Chafey P, Billuart P, Koulakoff A, Vinet MC, Schaar BT, McConnell SK, Francis F, Chelly J. Doublecortin interacts with mu subunits of clathrin adaptor complexes in the developing nervous system. Mol Cell Neurosci 2001; 18:307-19. [PMID: 11591131 DOI: 10.1006/mcne.2001.1022] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Doublecortin is a microtubule-associated protein required for normal corticogenesis in the developing brain. We carried out a yeast two-hybrid screen to identify interacting proteins. One of the isolated clones encodes the mu1 subunit of the adaptor complex AP-1 involved in clathrin-dependent protein sorting. We found that Doublecortin also interacts in yeast with mu2 from the AP-2 complex. Mutagenesis and pull-down experiments showed that these interactions were mediated through a tyrosine-based sorting signal (YLPL) in the C-terminal part of Doublecortin. The functional relevance of these interactions was suggested by the coimmunoprecipitation of Doublecortin with AP-1 and AP-2 from mouse brain extracts. This interaction was further supported by RNA in situ hybridization and immunofluorescence studies. Taken together these data indicate that a certain proportion of Doublecortin interacts with AP-1 and/or AP-2 in vivo and are consistent with a potential involvement of Doublecortin in protein sorting or vesicular trafficking.
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Affiliation(s)
- G Friocourt
- Laboratoire de Génétique et Physiopathologie des retards mentaux, ICGM, INSERM, CHU, Cochin, 24, rue du Faubourg Saint Jacques, Paris, 75014, France
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10
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Bordet T, Castelnau-Ptakhine L, Fauchereau F, Friocourt G, Kahn A, Haase G. Neuronal Targeting of Cardiotrophin-1 by Coupling with Tetanus Toxin C Fragment. Mol Cell Neurosci 2001; 17:842-54. [PMID: 11358482 DOI: 10.1006/mcne.2001.0979] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [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] Open
Abstract
Cardiotrophin-1 (CT-1) is a potent neurotrophic factor for motoneurons but its clinical use in motor neuron diseases is precluded by side effects on the heart and liver. We explored the possibility of targeting CT-1 to neurons by coupling with the tetanus toxin fragment TTC. Genetic fusion proteins between CT-1 or GFP and TTC were produced in Escherichia coli and assayed in vitro. In contrast to uncoupled CT-1 or GFP, TTC-coupled proteins bound with high affinity to cerebral neurons and spinal cord motoneurons and were rapidly internalized. Glia, hepatocytes, or cardiomyocytes did not show detectable binding or uptake of TTC-coupled proteins. Similar to CT-1, TTC-coupled CT-1 induced IL-6 secretion by KB cells, activated Reg-2 gene expression, and promoted motoneuron survival in a dose-dependent manner. In vivo studies will test whether TTC-coupled CT-1 might be targeted to degenerating spinal cord or brain-stem motoneurons and migrate trans-synaptically to cortical motoneurons, which are also affected in amyotrophic lateral sclerosis.
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Affiliation(s)
- T Bordet
- INSERM U.129, Institut Cochin de Génétique Moléculaire, 24, Rue du Faubourg St Jacques, 75014 Paris, France
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11
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Zemni R, Bienvenu T, Vinet MC, Sefiani A, Carrié A, Billuart P, McDonell N, Couvert P, Francis F, Chafey P, Fauchereau F, Friocourt G, des Portes V, Cardona A, Frints S, Meindl A, Brandau O, Ronce N, Moraine C, van Bokhoven H, Ropers HH, Sudbrak R, Kahn A, Fryns JP, Beldjord C, Chelly J. A new gene involved in X-linked mental retardation identified by analysis of an X;2 balanced translocation. Nat Genet 2000; 24:167-70. [PMID: 10655063 DOI: 10.1038/72829] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.5] [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: 11/08/2022]
Abstract
X-linked forms of mental retardation (MR) affect approximately 1 in 600 males and are likely to be highly heterogeneous. They can be categorized into syndromic (MRXS) and nonspecific (MRX) forms. In MRX forms, affected patients have no distinctive clinical or biochemical features. At least five MRX genes have been identified by positional cloning, but each accounts for only 0.5%-1.0% of MRX cases. Here we show that the gene TM4SF2 at Xp11.4 is inactivated by the X breakpoint of an X;2 balanced translocation in a patient with MR. Further investigation led to identification of TM4SF2 mutations in 2 of 33 other MRX families. RNA in situ hybridization showed that TM4SF2 is highly expressed in the central nervous system, including the cerebral cortex and hippocampus. TM4SF2 encodes a member of the tetraspanin family of proteins, which are known to contribute in molecular complexes including beta-1 integrins. We speculate that through this interaction, TM4SF2 might have a role in the control of neurite outgrowth.
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Affiliation(s)
- R Zemni
- INSERM Unité 129 - ICGM, CHU Cochin, Paris, France
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12
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Francis F, Koulakoff A, Boucher D, Chafey P, Schaar B, Vinet MC, Friocourt G, McDonnell N, Reiner O, Kahn A, McConnell SK, Berwald-Netter Y, Denoulet P, Chelly J. Doublecortin is a developmentally regulated, microtubule-associated protein expressed in migrating and differentiating neurons. Neuron 1999; 23:247-56. [PMID: 10399932 DOI: 10.1016/s0896-6273(00)80777-1] [Citation(s) in RCA: 776] [Impact Index Per Article: 31.0] [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: 12/24/2022]
Abstract
Recently, we and others reported that the doublecortin gene is responsible for X-linked lissencephaly and subcortical laminar heterotopia. Here, we show that Doublecortin is expressed in the brain throughout the period of corticogenesis in migrating and differentiating neurons. Immunohistochemical studies show its localization in the soma and leading processes of tangentially migrating neurons, and a strong axonal labeling is observed in differentiating neurons. In cultured neurons, Doublecortin expression is highest in the distal parts of developing processes. We demonstrate by sedimentation and microscopy studies that Doublecortin is associated with microtubules (MTs) and postulate that it is a novel MAP. Our data suggest that the cortical dysgeneses associated with the loss of Doublecortin function might result from abnormal cytoskeletal dynamics in neuronal cell development.
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Affiliation(s)
- F Francis
- U129 de l'INSERM, Institut Cochin de Génétique Moléculaire, Paris.
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