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Ma L, Kasula RK, Ouyang Q, Schmidt M, Morrow EM. GGA1 interacts with the endosomal Na+/H+ exchanger NHE6 governing localization to the endosome compartment. J Biol Chem 2024; 300:107552. [PMID: 39002678 PMCID: PMC11375261 DOI: 10.1016/j.jbc.2024.107552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/15/2024] Open
Abstract
Mutations in the endosomal Na+/H+ exchanger 6 (NHE6) cause Christianson syndrome, an X-linked neurological disorder. NHE6 functions in regulation of endosome acidification and maturation in neurons. Using yeast two-hybrid screening with the NHE6 carboxyl terminus as bait, we identify Golgi-associated, gamma adaptin ear-containing, ADP-ribosylation factor (ARF) binding protein 1 (GGA1) as an interacting partner for NHE6. We corroborated the NHE6-GGA1 interaction using: coimmunoprecipitation; overexpressed constructs in mammalian cells; and coimmunoprecipitation of endogenously expressed GGA1 and NHE6 from neuroblastoma cells, as well as from the mouse brain. We demonstrate that GGA1 interacts with organellar NHEs (NHE6, NHE7, and NHE9) and that there is significantly less interaction with cell-surface localized NHEs (NHE1 and NHE5). By constructing hybrid NHE1/NHE6 exchangers, we demonstrate the cytoplasmic tail of NHE6 interacts most strongly with GGA1. We demonstrate the colocalization of NHE6 and GGA1 in cultured, primary hippocampal neurons, using super-resolution microscopy. We test the hypothesis that the interaction of NHE6 and GGA1 functions in the localization of NHE6 to the endosome compartment. Using subcellular fractionation experiments, we show that NHE6 is mislocalized in GGA1 KO cells, wherein we find less NHE6 in endosomes, but more NHE6 transport to lysosomes, and more Golgi retention of NHE6, with increased exocytosis to the surface plasma membrane. Consistent with NHE6 mislocalization, and Golgi retention, we find the intraluminal pH in Golgi to be alkalinized in GGA1-null cells. Our study demonstrates a new interaction between NHE6 and GGA1 which functions in the localization of this intracellular NHE to the endosome compartment.
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Affiliation(s)
- Li Ma
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Ravi Kiran Kasula
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Qing Ouyang
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Michael Schmidt
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA
| | - Eric M Morrow
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA; Center for Translational Neuroscience, Brown University, Providence, Rhode Island, USA.
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2
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Viggiano M, Ceroni F, Visconti P, Posar A, Scaduto MC, Sandoni L, Baravelli I, Cameli C, Rochat MJ, Maresca A, Vaisfeld A, Gentilini D, Calzari L, Carelli V, Zody MC, Maestrini E, Bacchelli E. Genomic analysis of 116 autism families strengthens known risk genes and highlights promising candidates. NPJ Genom Med 2024; 9:21. [PMID: 38519481 PMCID: PMC10959942 DOI: 10.1038/s41525-024-00411-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 02/27/2024] [Indexed: 03/25/2024] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with a strong genetic component in which rare variants contribute significantly to risk. We performed whole genome and/or exome sequencing (WGS and WES) and SNP-array analysis to identify both rare sequence and copy number variants (SNVs and CNVs) in 435 individuals from 116 ASD families. We identified 37 rare potentially damaging de novo SNVs (pdSNVs) in the cases (n = 144). Interestingly, two of them (one stop-gain and one missense variant) occurred in the same gene, BRSK2. Moreover, the identification of 8 severe de novo pdSNVs in genes not previously implicated in ASD (AGPAT3, IRX5, MGAT5B, RAB8B, RAP1A, RASAL2, SLC9A1, YME1L1) highlighted promising candidates. Potentially damaging CNVs (pdCNVs) provided support to the involvement of inherited variants in PHF3, NEGR1, TIAM1 and HOMER1 in neurodevelopmental disorders (NDD), although mostly acting as susceptibility factors with incomplete penetrance. Interpretation of identified pdSNVs/pdCNVs according to the ACMG guidelines led to a molecular diagnosis in 19/144 cases, although this figure represents a lower limit and is expected to increase thanks to further clarification of the role of likely pathogenic variants in ASD/NDD candidate genes not yet established. In conclusion, our study highlights promising ASD candidate genes and contributes to characterize the allelic diversity, mode of inheritance and phenotypic impact of de novo and inherited risk variants in ASD/NDD genes.
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Affiliation(s)
- Marta Viggiano
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Fabiola Ceroni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Paola Visconti
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Disturbi dello Spettro Autistico, Bologna, Italy
| | - Annio Posar
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Disturbi dello Spettro Autistico, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Maria Cristina Scaduto
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOSI Disturbi dello Spettro Autistico, Bologna, Italy
| | - Laura Sandoni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Irene Baravelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Cinzia Cameli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Magali J Rochat
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Functional and Molecular Neuroimaging Unit, Bologna, Italy
| | - Alessandra Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Alessandro Vaisfeld
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Davide Gentilini
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Bioinformatics and Statistical Genomic Unit, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Luciano Calzari
- Bioinformatics and Statistical Genomic Unit, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | | | - Elena Maestrini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
| | - Elena Bacchelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
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Maroofian R, Zamani M, Kaiyrzhanov R, Liebmann L, Karimiani EG, Vona B, Huebner AK, Calame DG, Misra VK, Sadeghian S, Azizimalamiri R, Mohammadi MH, Zeighami J, Heydaran S, Toosi MB, Akhondian J, Babaei M, Hashemi N, Schnur RE, Suri M, Setzke J, Wagner M, Brunet T, Grochowski CM, Emrick L, Chung WK, Hellmich UA, Schmidts M, Lupski JR, Galehdari H, Severino M, Houlden H, Hübner CA. Biallelic variants in SLC4A10 encoding a sodium-dependent bicarbonate transporter lead to a neurodevelopmental disorder. Genet Med 2024; 26:101034. [PMID: 38054405 PMCID: PMC11157690 DOI: 10.1016/j.gim.2023.101034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/21/2023] [Accepted: 11/24/2023] [Indexed: 12/07/2023] Open
Abstract
PURPOSE SLC4A10 encodes a plasma membrane-bound transporter, which mediates Na+-dependent HCO3- import, thus mediating net acid extrusion. Slc4a10 knockout mice show collapsed brain ventricles, an increased seizure threshold, mild behavioral abnormalities, impaired vision, and deafness. METHODS Utilizing exome/genome sequencing in families with undiagnosed neurodevelopmental disorders and international data sharing, 11 patients from 6 independent families with biallelic variants in SLC4A10 were identified. Clinico-radiological and dysmorphology assessments were conducted. A minigene assay, localization studies, intracellular pH recordings, and protein modeling were performed to study the possible functional consequences of the variant alleles. RESULTS The families harbor 8 segregating ultra-rare biallelic SLC4A10 variants (7 missense and 1 splicing). Phenotypically, patients present with global developmental delay/intellectual disability and central hypotonia, accompanied by variable speech delay, microcephaly, cerebellar ataxia, facial dysmorphism, and infrequently, epilepsy. Neuroimaging features range from some non-specific to distinct neuroradiological findings, including slit ventricles and a peculiar form of bilateral curvilinear nodular heterotopia. In silico analyses showed 6 of 7 missense variants affect evolutionarily conserved residues. Functional analyses supported the pathogenicity of 4 of 7 missense variants. CONCLUSION We provide evidence that pathogenic biallelic SLC4A10 variants can lead to neurodevelopmental disorders characterized by variable abnormalities of the central nervous system, including altered brain ventricles, thus resembling several features observed in knockout mice.
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Affiliation(s)
- Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom.
| | - Mina Zamani
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran; Narges Medical Genetics and Prenatal Diagnosis Laboratory, Kianpars, Ahvaz, Iran
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, Am Klinikum 1, Jena, Germany
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace, London, United Kingdom
| | - Barbara Vona
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany; Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Antje K Huebner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, Am Klinikum 1, Jena, Germany
| | - Daniel G Calame
- Division of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX; Texas Children's Hospital, Houston, TX; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Vinod K Misra
- Division of Genetic, Genomic & Metabolic Disorders, Discipline of Pediatrics, College of Medicine, Central Michigan University, Mount Pleasant, MI
| | - Saeid Sadeghian
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Reza Azizimalamiri
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Jawaher Zeighami
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, Kianpars, Ahvaz, Iran
| | - Sogand Heydaran
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran; Neuroscience Research Center, Mashhad University of Medical Science, Mashhad, Iran
| | - Javad Akhondian
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Meisam Babaei
- Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Narges Hashemi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Mohnish Suri
- Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Jonas Setzke
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany; Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany; Department of Pediatric Neurology and Developmental Medicine and LMU Center for Children with Medical Complexity, Dr. von Hauner Children's Hospital, LMU Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Theresa Brunet
- Institute of Human Genetics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Lisa Emrick
- Division of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX; Texas Children's Hospital, Houston, TX; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Ute A Hellmich
- Friedrich Schiller University Jena, Faculty of Chemistry and Earth Sciences, Institute of Organic Chemistry and Macromolecular Chemistry, Jena, Germany; Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt, Germany; Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Miriam Schmidts
- Pediatrics Genetics Division, Center for Pediatrics and Adolescent Medicine, Faculty of Medicine, Freiburg University, Freiburg, Germany; Genome Research Division, Human Genetics Department, Radboud University Medical Center, Nijmegen, The Netherlands; CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - James R Lupski
- Texas Children's Hospital, Houston, TX; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Hamid Galehdari
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | | | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, Am Klinikum 1, Jena, Germany; Center for Rare Diseases, Jena University Hospital, Jena, Germany
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4
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Ma L, Kasula RK, Ouyang Q, Schmidt M, Morrow EM. GGA1 interacts with the endosomal Na+/H+ Exchanger NHE6 governing localization to the endosome compartment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.565997. [PMID: 37986849 PMCID: PMC10659387 DOI: 10.1101/2023.11.08.565997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Mutations in the endosomal Na+/H+ exchanger (NHE6) cause Christianson syndrome (CS), an X-linked neurological disorder. Previous studies have shown that NHE6 functions in regulation of endosome acidification and maturation in neurons. Using yeast two-hybrid screening with the NHE6 carboxyl-terminus as bait, we identify Golgi-associated, Gamma adaptin ear containing, ARF binding protein 1 (GGA1) as an interacting partner for NHE6. We corroborated the NHE6-GGA1 interaction using co-immunoprecipitation (co-IP): using over-expressed constructs in mammalian cells; and co-IP of endogenously-expressed GGA1 and NHE6 from neuroblastoma cells, as well as from mouse brain. We demonstrate that GGA1 interacts with organellar NHEs (NHE6, NHE7 and NHE9) but not with cell-surface localized NHEs (NHE1 and NHE5). By constructing hybrid NHE1/NHE6 exchangers, we demonstrate that the cytoplasmic tail of NHE6 is necessary and sufficient for interactions with GGA1. We demonstrate the co-localization of NHE6 and GGA1 in cultured, primary hippocampal neurons, using super-resolution microscopy. We test the hypothesis that the interaction of NHE6 and GGA1 functions in the localization of NHE6 to the endosome compartment. Using subcellular fractionation experiments, we show that NHE6 is mis-localized in GGA1 knockout cells wherein we find less NHE6 in endosomes but more NHE6 transport to lysosomes, and more Golgi retention of NHE6 with increased exocytosis to the surface plasma membrane. Consistent with NHE6 mis-localization, and Golgi retention, we find the intra-luminal pH in Golgi to be alkalinized. Our study demonstrates a new interaction between NHE6 and GGA1 which functions in the localization of this intra-cellular NHE to the endosome compartment.
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5
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Fasham J, Huebner AK, Liebmann L, Khalaf-Nazzal R, Maroofian R, Kryeziu N, Wortmann SB, Leslie JS, Ubeyratna N, Mancini GMS, van Slegtenhorst M, Wilke M, Haack TB, Shamseldin HE, Gleeson JG, Almuhaizea M, Dweikat I, Abu-Libdeh B, Daana M, Zaki MS, Wakeling MN, McGavin L, Turnpenny PD, Alkuraya FS, Houlden H, Schlattmann P, Kaila K, Crosby AH, Baple EL, Hübner CA. SLC4A10 mutation causes a neurological disorder associated with impaired GABAergic transmission. Brain 2023; 146:4547-4561. [PMID: 37459438 PMCID: PMC10629776 DOI: 10.1093/brain/awad235] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/19/2023] [Accepted: 06/06/2023] [Indexed: 11/09/2023] Open
Abstract
SLC4A10 is a plasma-membrane bound transporter that utilizes the Na+ gradient to drive cellular HCO3- uptake, thus mediating acid extrusion. In the mammalian brain, SLC4A10 is expressed in principal neurons and interneurons, as well as in epithelial cells of the choroid plexus, the organ regulating the production of CSF. Using next generation sequencing on samples from five unrelated families encompassing nine affected individuals, we show that biallelic SLC4A10 loss-of-function variants cause a clinically recognizable neurodevelopmental disorder in humans. The cardinal clinical features of the condition include hypotonia in infancy, delayed psychomotor development across all domains and intellectual impairment. Affected individuals commonly display traits associated with autistic spectrum disorder including anxiety, hyperactivity and stereotyped movements. In two cases isolated episodes of seizures were reported in the first few years of life, and a further affected child displayed bitemporal epileptogenic discharges on EEG without overt clinical seizures. While occipitofrontal circumference was reported to be normal at birth, progressive postnatal microcephaly evolved in 7 out of 10 affected individuals. Neuroradiological features included a relative preservation of brain volume compared to occipitofrontal circumference, characteristic narrow sometimes 'slit-like' lateral ventricles and corpus callosum abnormalities. Slc4a10 -/- mice, deficient for SLC4A10, also display small lateral brain ventricles and mild behavioural abnormalities including delayed habituation and alterations in the two-object novel object recognition task. Collapsed brain ventricles in both Slc4a10-/- mice and affected individuals suggest an important role of SLC4A10 in the production of the CSF. However, it is notable that despite diverse roles of the CSF in the developing and adult brain, the cortex of Slc4a10-/- mice appears grossly intact. Co-staining with synaptic markers revealed that in neurons, SLC4A10 localizes to inhibitory, but not excitatory, presynapses. These findings are supported by our functional studies, which show the release of the inhibitory neurotransmitter GABA is compromised in Slc4a10-/- mice, while the release of the excitatory neurotransmitter glutamate is preserved. Manipulation of intracellular pH partially rescues GABA release. Together our studies define a novel neurodevelopmental disorder associated with biallelic pathogenic variants in SLC4A10 and highlight the importance of further analyses of the consequences of SLC4A10 loss-of-function for brain development, synaptic transmission and network properties.
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Affiliation(s)
- James Fasham
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Antje K Huebner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany
| | - Reham Khalaf-Nazzal
- Department of Biomedical Sciences, Faculty of Medicine, Arab American University of Palestine, Jenin, P227, Palestine
| | - Reza Maroofian
- Molecular and Clinical Sciences Institute, St. George’s University of London, London SW17 0RE, UK
| | - Nderim Kryeziu
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany
| | - Saskia B Wortmann
- University Children’s Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
- Amalia Children’s Hospital, Radboudumc, 6525 GA Nijmegen, The Netherlands
- Institute of Human Genetics, Technische Universität München, 80333 Munich, Germany
| | - Joseph S Leslie
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Nishanka Ubeyratna
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | | | - Martina Wilke
- Department of Clinical Genetics, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, 72076 Tübingen, Germany
| | - Hanan E Shamseldin
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Joseph G Gleeson
- Rady Children’s Institute for Genomic Medicine, San Diego, CA 92123, USA
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mohamed Almuhaizea
- Department of Neuroscience, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Imad Dweikat
- Department of Biomedical Sciences, Faculty of Medicine, Arab American University of Palestine, Jenin, P227, Palestine
| | - Bassam Abu-Libdeh
- Department of Pediatrics and Genetics, Makassed Hospital and Al-Quds University, East Jerusalem, 95908, Palestine
| | - Muhannad Daana
- Department of Pediatrics, Arab Women’s Union Hospital, Nablus, P400, Palestine
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Dokki, Cairo 12622, Egypt
| | - Matthew N Wakeling
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Lucy McGavin
- Department of Radiology, Derriford Hospital, Plymouth PL6 8DH, UK
| | - Peter D Turnpenny
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - Henry Houlden
- Molecular and Clinical Sciences Institute, St. George’s University of London, London SW17 0RE, UK
| | - Peter Schlattmann
- Institute for Medical Statistics, Computer Science and Data Science, Jena University Hospital, 07747 Jena, Germany
| | - Kai Kaila
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Andrew H Crosby
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Emma L Baple
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
- Peninsula Clinical Genetics Service, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany
- Center for Rare Diseases, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany
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6
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Gardner CC, James PF. Na +/H + Exchangers (NHEs) in Mammalian Sperm: Essential Contributors to Male Fertility. Int J Mol Sci 2023; 24:14981. [PMID: 37834431 PMCID: PMC10573352 DOI: 10.3390/ijms241914981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Na+/H+ exchangers (NHEs) are known to be important regulators of pH in multiple intracellular compartments of eukaryotic cells. Sperm function is especially dependent on changes in pH and thus it has been postulated that NHEs play important roles in regulating the intracellular pH of these cells. For example, in order to achieve fertilization, mature sperm must maintain a basal pH in the male reproductive tract and then alkalize in response to specific signals in the female reproductive tract during the capacitation process. Eight NHE isoforms are expressed in mammalian testis/sperm: NHE1, NHE3, NHE5, NHE8, NHA1, NHA2, NHE10, and NHE11. These NHE isoforms are expressed at varying times during spermatogenesis and localize to different subcellular structures in developing and mature sperm where they contribute to multiple aspects of sperm physiology and male fertility including proper sperm development/morphogenesis, motility, capacitation, and the acrosome reaction. Previous work has provided evidence for NHE3, NHE8, NHA1, NHA2, and NHE10 being critical for male fertility in mice and NHE10 has recently been shown to be essential for male fertility in humans. In this article we review what is known about each NHE isoform expressed in mammalian sperm and discuss the physiological significance of each NHE isoform with respect to male fertility.
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Affiliation(s)
| | - Paul F. James
- Department of Biology, Miami University, Oxford, OH 45056, USA;
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7
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Cengiz Winter N, Karakaya M, Mosen P, Brusius I, Anlar B, Haliloglu G, Winter D, Wirth B. Proteomic Investigation of Differential Interactomes of Glypican 1 and a Putative Disease-Modifying Variant of Ataxia. J Proteome Res 2023; 22:3081-3095. [PMID: 37585105 PMCID: PMC10476613 DOI: 10.1021/acs.jproteome.3c00402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Indexed: 08/17/2023]
Abstract
In a currently 13-year-old girl of consanguineous Turkish parents, who developed unsteady gait and polyneuropathy at the ages of 3 and 6 years, respectively, we performed whole genome sequencing and identified a biallelic missense variant c.424C>T, p.R142W in glypican 1 (GPC1) as a putative disease-associated variant. Up to date, GPC1 has not been associated with a neuromuscular disorder, and we hypothesized that this variant, predicted as deleterious, may be causative for the disease. Using mass spectrometry-based proteomics, we investigated the interactome of GPC1 WT and the missense variant. We identified 198 proteins interacting with GPC1, of which 16 were altered for the missense variant. This included CANX as well as vacuolar ATPase (V-ATPase) and the mammalian target of rapamycin complex 1 (mTORC1) complex members, whose dysregulation could have a potential impact on disease severity in the patient. Importantly, these proteins are novel interaction partners of GPC1. At 10.5 years, the patient developed dilated cardiomyopathy and kyphoscoliosis, and Friedreich's ataxia (FRDA) was suspected. Given the unusually severe phenotype in a patient with FRDA carrying only 104 biallelic GAA repeat expansions in FXN, we currently speculate that disturbed GPC1 function may have exacerbated the disease phenotype. LC-MS/MS data are accessible in the ProteomeXchange Consortium (PXD040023).
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Affiliation(s)
- Nur Cengiz Winter
- Institute
of Human Genetics, University Hospital Cologne, 50931 Cologne, Germany
- Center
for Molecular Medicine Cologne, University
of Cologne, 50931 Cologne, Germany
| | - Mert Karakaya
- Institute
of Human Genetics, University Hospital Cologne, 50931 Cologne, Germany
- Center
for Molecular Medicine Cologne, University
of Cologne, 50931 Cologne, Germany
- Center
for Rare Diseases Cologne, University Hospital
of Cologne, 50931 Cologne, Germany
| | - Peter Mosen
- Institute
for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - Isabell Brusius
- Institute
of Human Genetics, University Hospital Cologne, 50931 Cologne, Germany
| | - Banu Anlar
- Department
of Pediatrics, Division of Pediatric Neurology, Hacettepe University Faculty of Medicine, 06230 Ankara, Turkey
| | - Goknur Haliloglu
- Department
of Pediatrics, Division of Pediatric Neurology, Hacettepe University Faculty of Medicine, 06230 Ankara, Turkey
| | - Dominic Winter
- Institute
for Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - Brunhilde Wirth
- Institute
of Human Genetics, University Hospital Cologne, 50931 Cologne, Germany
- Center
for Molecular Medicine Cologne, University
of Cologne, 50931 Cologne, Germany
- Center
for Rare Diseases Cologne, University Hospital
of Cologne, 50931 Cologne, Germany
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8
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Shi X, Li J, Liu T, Zhao H, Leng H, Sun K, Feng J. Divergence of cochlear transcriptomics between reference‑based and reference‑free transcriptome analyses among Rhinolophus ferrumequinum populations. PLoS One 2023; 18:e0288404. [PMID: 37432940 DOI: 10.1371/journal.pone.0288404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/26/2023] [Indexed: 07/13/2023] Open
Abstract
Differences in gene expression within tissues can lead to differences in tissue function. Understanding the transcriptome of a species helps elucidate the molecular mechanisms underlying phenotypic divergence. According to the presence or absence of a reference genome of for a studied species, transcriptome analyses can be divided into reference‑based and reference‑free methods, respectively. Presently, comparisons of complete transcriptome analysis results between those two methods are still rare. In this study, we compared the cochlear transcriptome analysis results of greater horseshoe bats (Rhinolophus ferrumequinum) from three lineages in China with different acoustic phenotypes using reference‑based and reference‑free methods to explore their differences in subsequent analysis. The results gained by reference-based results had lower false-positive rates and were more accurate because differentially expressed genes among the three populations obtained by this method had greater reliability and a higher annotation rate. Some phenotype-related enrichment terms, including those related to inorganic molecules and proton transmembrane channels, were also obtained only by the reference-based method. However, the reference‑based method might have the limitation of incomplete information acquisition. Thus, we believe that a combination of reference‑free and reference‑based methods is ideal for transcriptome analyses. The results of our study provided a reference for the selection of transcriptome analysis methods in the future.
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Affiliation(s)
- Xiaoxiao Shi
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, Jilin, China
| | - Jun Li
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, Jilin, China
| | - Tong Liu
- Department of Life Science, Jilin Agricultural University, Changchun, Jilin, China
| | - Hanbo Zhao
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural, Shenzhen, China
| | - Haixia Leng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, Jilin, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, Jilin, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, Jilin, China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, Jilin, China
- Department of Life Science, Jilin Agricultural University, Changchun, Jilin, China
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9
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Chander V, Mahmoud M, Hu J, Dardas Z, Grochowski CM, Dawood M, Khayat MM, Li H, Li S, Jhangiani S, Korchina V, Shen H, Weissenberger G, Meng Q, Gingras MC, Muzny DM, Doddapaneni H, Posey JE, Lupski JR, Sabo A, Murdock DR, Sedlazeck FJ, Gibbs RA. Long read sequencing and expression studies of AHDC1 deletions in Xia-Gibbs syndrome reveal a novel genetic regulatory mechanism. Hum Mutat 2022; 43:2033-2053. [PMID: 36054313 PMCID: PMC10167679 DOI: 10.1002/humu.24461] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/17/2022] [Accepted: 08/30/2022] [Indexed: 01/25/2023]
Abstract
Xia-Gibbs syndrome (XGS; MIM# 615829) is a rare mendelian disorder characterized by Development Delay (DD), intellectual disability (ID), and hypotonia. Individuals with XGS typically harbor de novo protein-truncating mutations in the AT-Hook DNA binding motif containing 1 (AHDC1) gene, although some missense mutations can also cause XGS. Large de novo heterozygous deletions that encompass the AHDC1 gene have also been ascribed as diagnostic for the disorder, without substantial evidence to support their pathogenicity. We analyzed 19 individuals with large contiguous deletions involving AHDC1, along with other genes. One individual bore the smallest known contiguous AHDC1 deletion (∼350 Kb), encompassing eight other genes within chr1p36.11 (Feline Gardner-Rasheed, IFI6, FAM76A, STX12, PPP1R8, THEMIS2, RPA2, SMPDL3B) and terminating within the first intron of AHDC1. The breakpoint junctions and phase of the deletion were identified using both short and long read sequencing (Oxford Nanopore). Quantification of RNA expression patterns in whole blood revealed that AHDC1 exhibited a mono-allelic expression pattern with no deficiency in overall AHDC1 expression levels, in contrast to the other deleted genes, which exhibited a 50% reduction in mRNA expression. These results suggest that AHDC1 expression in this individual is compensated by a novel regulatory mechanism and advances understanding of mutational and regulatory mechanisms in neurodevelopmental disorders.
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Affiliation(s)
- Varuna Chander
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Medhat Mahmoud
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jianhong Hu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Zain Dardas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Moez Dawood
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Michael M. Khayat
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - He Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Shoudong Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Shalini Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Viktoriya Korchina
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Hua Shen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | | | - Qingchang Meng
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Marie-Claude Gingras
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Donna M. Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Harsha Doddapaneni
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - James R. Lupski
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Texas Children’s Hospital, Houston, Texas, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Aniko Sabo
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - David R. Murdock
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Fritz J. Sedlazeck
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Computer Science, Rice University, Houston, Texas, USA
| | - Richard A. Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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10
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Li Y, Fan C, Wang C, Wang L, Yi Y, Mao X, Chen X, Lan T, Wang W, Yu SY. Stress-induced reduction of Na +/H + exchanger isoform 1 promotes maladaptation of neuroplasticity and exacerbates depressive behaviors. SCIENCE ADVANCES 2022; 8:eadd7063. [PMID: 36367929 PMCID: PMC9651740 DOI: 10.1126/sciadv.add7063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/23/2022] [Indexed: 05/29/2023]
Abstract
Major depression disorder (MDD) is a neuropsychiatric disorder characterized by abnormal neuronal activity in specific brain regions. A factor that is crucial in maintaining normal neuronal functioning is intracellular pH (pHi) homeostasis. In this study, we show that chronic stress, which induces depression-like behaviors in animal models, down-regulates the expression of the hippocampal Na+/H+ exchanger isoform 1, NHE1, a major determinant of pHi in neurons. Knockdown of NHE1 in CA1 hippocampal pyramidal neurons leads to intracellular acidification, promotes dendritic spine loss, lowers excitatory synaptic transmission, and enhances the susceptibility to stress exposure in rats. Moreover, E3 ubiquitin ligase cullin4A may promote ubiquitination and degradation of NHE1 to induce these effects of an unbalanced pHi on synaptic processes. Electrophysiological data further suggest that the abnormal excitability of hippocampal neurons caused by maladaptation of neuroplasticity may be involved in the pathogenesis of this disease. These findings elucidate a mechanism for pHi homeostasis alteration as related to MDD.
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Affiliation(s)
- Ye Li
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Cuiqin Fan
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Changmin Wang
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Liyan Wang
- Morphological Experimental Center, Shandong University, School of Basic Medical Sciences, 44 Wenhuaxilu Road, Jinan, Shandong 250012, PR China
| | - Yuhang Yi
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Xueqin Mao
- Department of Psychology, Qilu Hospital of Shandong University, 107 Wenhuaxilu Road, Jinan, Shandong 250012, PR China
| | - Xiao Chen
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Tian Lan
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Wenjing Wang
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
| | - Shu Yan Yu
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
- Shandong Provincial Key Laboratory of Mental Disorders, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, PR China
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11
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Protasova MS, Gusev FE, Andreeva TV, Klyushnikov SA, Illarioshkin SN, Rogaev EI. Novel genes bearing mutations in rare cases of early-onset ataxia with cerebellar hypoplasia. Eur J Hum Genet 2022; 30:703-711. [PMID: 35351988 DOI: 10.1038/s41431-022-01088-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 02/09/2022] [Accepted: 03/10/2022] [Indexed: 12/13/2022] Open
Abstract
We propose an approach for the identification of mutant genes for rare diseases in single cases of unknown etiology. All genes with rare biologically significant variants sorted from individual exome data are tested further for profiling of their spatial-temporal and cell/tissue specific expression compared to that of their paralogs. We developed a simple bioinformatics tool ("Essential Paralogue by Expression" (EPbE)) for such analysis. Here, we present rare clinical forms of early ataxia with cerebellar hypoplasia. Using whole-exome sequencing and the EPbE tool, we identified two novel mutant genes previously not associated with congenital human diseases. In Family I, the unique missense mutation (p.Lys258Glu) was found in the LRCH2 gene inherited in an X-linked manner. p.Lys258Glu occurs in the evolutionarily invariant site of the leucine-rich repeat domain of LRCH2. In Family II and Family III, the identical genetic variant was found in the CSMD1 gene inherited as an autosomal-recessive trait. The variant leads to amino acid substitution p.Gly2979Ser in a highly conserved region of the complement-interacting domain of CSMD1. The LRCH2 gene for Family I patients (in which congenital cerebellar hypoplasia was associated with demyelinating polyneuropathy) is expressed in Schwann and precursor Schwann cells and predominantly over its paralogous genes in the developing cerebellar cortex. The CSMD1 gene is predominantly expressed over its paralogous genes in the cerebellum, specifically in the period of late childhood. Thus, the comparative spatial-temporal expression of the selected genes corresponds to the neurological manifestations of the disease.
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Affiliation(s)
- Maria S Protasova
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia
| | - Fedor E Gusev
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia
| | - Tatiana V Andreeva
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia.,Faculty of Biology, Lomonosov Moscow State University, 119234, Moscow, Russia
| | - Sergey A Klyushnikov
- Department of Neurogenetics, Research Center of Neurology, 123367, Moscow, Russia
| | | | - Evgeny I Rogaev
- Laboratory of Evolutionary Genomics, Department of Genomics and Human Genetics, Vavilov Institute of General Genetics Russian Academy of Sciences, 119333, Moscow, Russia. .,Center for Genetics and Life Science, Sirius University of Science and Technology, 354340, Sochi, Russia. .,Department of Psychiatry, UMass Chan Medical School, Shrewsbury, MA, 01545, USA.
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12
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Gao AYL, Lourdin-De Filippis E, Orlowski J, McKinney RA. Roles of Endomembrane Alkali Cation/Proton Exchangers in Synaptic Function and Neurodevelopmental Disorders. Front Physiol 2022; 13:892196. [PMID: 35547574 PMCID: PMC9081726 DOI: 10.3389/fphys.2022.892196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/30/2022] [Indexed: 12/25/2022] Open
Abstract
Endomembrane alkali cation (Na+, K+)/proton (H+) exchangers (eNHEs) are increasingly associated with neurological disorders. These eNHEs play integral roles in regulating the luminal pH, processing, and trafficking of cargo along the secretory (Golgi and post-Golgi vesicles) and endocytic (early, recycling, and late endosomes) pathways, essential regulatory processes vital for neuronal development and plasticity. Given the complex morphology and compartmentalization of multipolar neurons, the contribution of eNHEs in maintaining optimal pH homeostasis and cargo trafficking is especially significant during periods of structural and functional development and remodeling. While the importance of eNHEs has been demonstrated in a variety of non-neuronal cell types, their involvement in neuronal function is less well understood. In this review, we will discuss their emerging roles in excitatory synaptic function, particularly as it pertains to cellular learning and remodeling. We will also explore their connections to neurodevelopmental conditions, including intellectual disability, autism, and attention deficit hyperactivity disorders.
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Affiliation(s)
- Andy Y L Gao
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
| | | | - John Orlowski
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - R Anne McKinney
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
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13
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Qian F, Jiang X, Chai R, Liu D. The Roles of Solute Carriers in Auditory Function. Front Genet 2022; 13:823049. [PMID: 35154281 PMCID: PMC8827148 DOI: 10.3389/fgene.2022.823049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Solute carriers (SLCs) are important transmembrane transporters with members organized into 65 families. They play crucial roles in transporting many important molecules, such as ions and some metabolites, across the membrane, maintaining cellular homeostasis. SLCs also play important roles in hearing. It has been found that mutations in some SLC members are associated with hearing loss. In this review, we summarize SLC family genes related with hearing dysfunction to reveal the vital roles of these transporters in auditory function. This summary could help us understand the auditory physiology and the mechanisms of hearing loss and further guide future studies of deafness gene identification.
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Affiliation(s)
- Fuping Qian
- School of Life Sciences, Nantong University, Nantong, China
| | - Xiaoge Jiang
- Department of Rehabilitation Medicine, The Second People's Hospital of Nantong, Affiliated Rehabilitation Hospital of Nantong University, Nantong, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China.,Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Dong Liu
- School of Life Sciences, Nantong University, Nantong, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
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14
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Dong Y, Gao Y, Ilie A, Kim D, Boucher A, Li B, Zhang XC, Orlowski J, Zhao Y. Structure and mechanism of the human NHE1-CHP1 complex. Nat Commun 2021; 12:3474. [PMID: 34108458 PMCID: PMC8190280 DOI: 10.1038/s41467-021-23496-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/29/2021] [Indexed: 02/05/2023] Open
Abstract
Sodium/proton exchanger 1 (NHE1) is an electroneutral secondary active transporter present on the plasma membrane of most mammalian cells and plays critical roles in regulating intracellular pH and volume homeostasis. Calcineurin B-homologous protein 1 (CHP1) is an obligate binding partner that promotes NHE1 biosynthetic maturation, cell surface expression and pH-sensitivity. Dysfunctions of either protein are associated with neurological disorders. Here, we elucidate structures of the human NHE1-CHP1 complex in both inward- and inhibitor (cariporide)-bound outward-facing conformations. We find that NHE1 assembles as a symmetrical homodimer, with each subunit undergoing an elevator-like conformational change during cation exchange. The cryo-EM map reveals the binding site for the NHE1 inhibitor cariporide, illustrating how inhibitors block transport activity. The CHP1 molecule differentially associates with these two conformational states of each NHE1 monomer, and this association difference probably underlies the regulation of NHE1 pH-sensitivity by CHP1.
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Affiliation(s)
- Yanli Dong
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yiwei Gao
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Alina Ilie
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - DuSik Kim
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Annie Boucher
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Bin Li
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xuejun C. Zhang
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - John Orlowski
- grid.14709.3b0000 0004 1936 8649Department of Physiology, McGill University, Montreal, QC Canada
| | - Yan Zhao
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ,grid.410726.60000 0004 1797 8419College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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15
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Plastin 3 in health and disease: a matter of balance. Cell Mol Life Sci 2021; 78:5275-5301. [PMID: 34023917 PMCID: PMC8257523 DOI: 10.1007/s00018-021-03843-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/06/2021] [Accepted: 04/20/2021] [Indexed: 02/06/2023]
Abstract
For a long time, PLS3 (plastin 3, also known as T-plastin or fimbrin) has been considered a rather inconspicuous protein, involved in F-actin-binding and -bundling. However, in recent years, a plethora of discoveries have turned PLS3 into a highly interesting protein involved in many cellular processes, signaling pathways, and diseases. PLS3 is localized on the X-chromosome, but shows sex-specific, inter-individual and tissue-specific expression variability pointing towards skewed X-inactivation. PLS3 is expressed in all solid tissues but usually not in hematopoietic cells. When escaping X-inactivation, PLS3 triggers a plethora of different types of cancers. Elevated PLS3 levels are considered a prognostic biomarker for cancer and refractory response to therapies. When it is knocked out or mutated in humans and mice, it causes osteoporosis with bone fractures; it is the only protein involved in actin dynamics responsible for osteoporosis. Instead, when PLS3 is upregulated, it acts as a highly protective SMN-independent modifier in spinal muscular atrophy (SMA). Here, it seems to counteract reduced F-actin levels by restoring impaired endocytosis and disturbed calcium homeostasis caused by reduced SMN levels. In contrast, an upregulation of PLS3 on wild-type level might cause osteoarthritis. This emphasizes that the amount of PLS3 in our cells must be precisely balanced; both too much and too little can be detrimental. Actin-dynamics, regulated by PLS3 among others, are crucial in a lot of cellular processes including endocytosis, cell migration, axonal growth, neurotransmission, translation, and others. Also, PLS3 levels influence the infection with different bacteria, mycosis, and other pathogens.
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16
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Yahia A, Stevanin G. The History of Gene Hunting in Hereditary Spinocerebellar Degeneration: Lessons From the Past and Future Perspectives. Front Genet 2021; 12:638730. [PMID: 33833777 PMCID: PMC8021710 DOI: 10.3389/fgene.2021.638730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/02/2021] [Indexed: 01/02/2023] Open
Abstract
Hereditary spinocerebellar degeneration (SCD) encompasses an expanding list of rare diseases with a broad clinical and genetic heterogeneity, complicating their diagnosis and management in daily clinical practice. Correct diagnosis is a pillar for precision medicine, a branch of medicine that promises to flourish with the progressive improvements in studying the human genome. Discovering the genes causing novel Mendelian phenotypes contributes to precision medicine by diagnosing subsets of patients with previously undiagnosed conditions, guiding the management of these patients and their families, and enabling the discovery of more causes of Mendelian diseases. This new knowledge provides insight into the biological processes involved in health and disease, including the more common complex disorders. This review discusses the evolution of the clinical and genetic approaches used to diagnose hereditary SCD and the potential of new tools for future discoveries.
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Affiliation(s)
- Ashraf Yahia
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
- Department of Biochemistry, Faculty of Medicine, National University, Khartoum, Sudan
- Institut du Cerveau, INSERM U1127, CNRS UMR7225, Sorbonne Université, Paris, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
| | - Giovanni Stevanin
- Institut du Cerveau, INSERM U1127, CNRS UMR7225, Sorbonne Université, Paris, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
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Role of Genetic Mutations of the Na +/H + Exchanger Isoform 1, in Human Disease and Protein Targeting and Activity. Mol Cell Biochem 2020; 476:1221-1232. [PMID: 33201382 DOI: 10.1007/s11010-020-03984-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/06/2020] [Indexed: 01/22/2023]
Abstract
The mammalian Na+/H+ exchanger isoform one (NHE1) is a plasma membrane protein that is ubiquitously present in human cells. It functions to regulate intracellular pH removing an intracellular proton in exchange for one extracellular sodium and is involved in heart disease and in promoting metastasis in cancer. It is made of a 500 amino acid membrane domain plus a 315 amino acid, regulatory cytosolic tail. The membrane domain is thought to have 12 transmembrane segments and a large membrane-associated extracellular loop. Early studies demonstrated that in mice, disruption of the NHE1 gene results in locomotor ataxia and a phenotype of slow-wave epilepsy. Defects included a progressive neuronal degeneration. Growth and reproductive ability were also reduced. Recent studies have identified human autosomal homozygous recessive mutations in the NHE1 gene (SLC9A1) that result in impaired development, ataxia and other severe defects, and explain the cause of the human disease Lichtenstein-Knorr syndrome. Other human mutations have been identified that are stop codon polymorphisms. These cause short non-functional NHE1 proteins, while other genetic polymorphisms in the NHE1 gene cause impaired expression of the NHE1 protein, reduced activity, enhanced protein degradation or altered kinetic activation of the protein. Since NHE1 plays a key role in many human physiological functions and in human disease, genetic polymorphisms of the protein that significantly alter its function and are likely play significant roles in varying human phenotypes and be involved in disease.
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18
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Bocker HT, Heinrich T, Liebmann L, Hennings JC, Seemann E, Gerth M, Jakovčevski I, Preobraschenski J, Kessels MM, Westermann M, Isbrandt D, Jahn R, Qualmann B, Hübner CA. The Na+/H+ Exchanger Nhe1 Modulates Network Excitability via GABA Release. Cereb Cortex 2020; 29:4263-4276. [PMID: 30541023 DOI: 10.1093/cercor/bhy308] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 01/06/2023] Open
Abstract
Brain functions are extremely sensitive to pH changes because of the pH-dependence of proteins involved in neuronal excitability and synaptic transmission. Here, we show that the Na+/H+ exchanger Nhe1, which uses the Na+ gradient to extrude H+, is expressed at both inhibitory and excitatory presynapses. We disrupted Nhe1 specifically in mice either in Emx1-positive glutamatergic neurons or in parvalbumin-positive cells, mainly GABAergic interneurons. While Nhe1 disruption in excitatory neurons had no effect on overall network excitability, mice with disruption of Nhe1 in parvalbumin-positive neurons displayed epileptic activity. From our electrophysiological analyses in the CA1 of the hippocampus, we conclude that the disruption in parvalbumin-positive neurons impairs the release of GABA-loaded vesicles, but increases the size of GABA quanta. The latter is most likely an indirect pH-dependent effect, as Nhe1 was not expressed in purified synaptic vesicles itself. Conclusively, our data provide first evidence that Nhe1 affects network excitability via modulation of inhibitory interneurons.
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Affiliation(s)
- Hartmut T Bocker
- Institute of Human Genetics, Jena University Hospital, 07747 Jena, Germany
| | - Theresa Heinrich
- Department GMP Cell and Gene Therapy, Fraunhofer Institute for Cell Therapy and Immunology IZI, 04103 Leipzig, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, 07747 Jena, Germany
| | | | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital, 07743 Jena, Germany
| | - Melanie Gerth
- Institute of Human Genetics, Jena University Hospital, 07747 Jena, Germany
| | - Igor Jakovčevski
- Institute for Molecular and Behavioral Neuroscience, University of Cologne, 50937 Cologne, Germany, and German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - Julia Preobraschenski
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Michael M Kessels
- Institute of Biochemistry I, Jena University Hospital, 07743 Jena, Germany
| | - Martin Westermann
- Electron Microscopy Center, Jena University Hospital, 07747 Jena, Germany
| | - Dirk Isbrandt
- Institute for Molecular and Behavioral Neuroscience, University of Cologne, 50937 Cologne, Germany, and German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital, 07743 Jena, Germany
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, 07747 Jena, Germany
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19
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Deafness and Vestibulopathy in Cerebellar Diseases: a Practical Approach. THE CEREBELLUM 2020; 18:1011-1016. [PMID: 31154624 DOI: 10.1007/s12311-019-01042-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cerebellar ataxias are a clinically heterogeneous group of neurological disorders. Besides the cerebellum, several forms of hereditary ataxias or non-genetic ataxias also affect other areas of the brain. Some forms of cerebellar ataxias may have cochlear and vestibular involvement and may present with deafness and symptoms or signs of vestibulopathy (dizziness, nystagmus and diplopia). Recognizing otoneurological symptoms in patients with cerebellar ataxias is mandatory, since these signs may guide a specific diagnosis, and clinicians may provide a suitable therapeutic approach. In this review, we describe and discuss the most common forms of cerebellar ataxias associated with deafness and vestibulopathy.
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20
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Amino Acids 563-566 of the Na +/H + Exchanger Isoform 1 C-Terminal Cytosolic Tail Prevent Protein Degradation and Stabilize Protein Expression and Activity. Int J Mol Sci 2020; 21:ijms21051737. [PMID: 32138345 PMCID: PMC7084640 DOI: 10.3390/ijms21051737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 12/28/2022] Open
Abstract
Isoform one of the mammalian Na+/H+ exchanger is a plasma membrane protein that is ubiquitously present in humans. It regulates intracellular pH through the removal of one intracellular proton in exchange for a single extracellular sodium. It consists of a 500 amino acid membrane domain plus a 315 amino acid, C-terminal tail. We examined amino acids of the C-terminal tail that are important in the targeting and activity of the protein. A previous study demonstrated that stop codon polymorphisms can result in decreased activity, expression, targeting and enhanced protein degradation. Here, we determine elements that are critical in these anomalies. A series of progressive deletions of the C-terminal tail demonstrated a progressive decrease in activity and targeting, though these remained until a final drop off with the deletion of amino acids 563–566. The deletion of the 562LIAGERS568 sequence or the alteration to the 562LAAAARS568 sequence caused the decreased protein expression, aberrant targeting, reduced activity and enhanced degradation of the Na+/H+ exchanger (NHE1) protein. The 562LIAGERS568 sequence bound to other regions of the C-terminal cytosolic domain. We suggest this region is necessary for the activity, targeting, stability, and expression of the NHE1 protein. The results define a new sequence that is important in maintenance of NHE1 protein levels and activity.
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21
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Liang S, Fuchs S, Mymrikov EV, Stulz A, Kaiser M, Heerklotz H, Hunte C. Calcium affects CHP1 and CHP2 conformation and their interaction with sodium/proton exchanger 1. FASEB J 2020; 34:3253-3266. [DOI: 10.1096/fj.201902093r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 12/10/2019] [Accepted: 12/23/2019] [Indexed: 01/27/2023]
Affiliation(s)
- Shuo Liang
- Institute for Biochemistry and Molecular Biology ZBMZ, Faculty of Medicine University of Freiburg Freiburg Germany
- Faculty of Biology University of Freiburg Freiburg Germany
| | - Simon Fuchs
- Institute for Biochemistry and Molecular Biology ZBMZ, Faculty of Medicine University of Freiburg Freiburg Germany
- Faculty of Biology University of Freiburg Freiburg Germany
| | - Evgeny V. Mymrikov
- Institute for Biochemistry and Molecular Biology ZBMZ, Faculty of Medicine University of Freiburg Freiburg Germany
- CIBSS ‐ Centre for Integrative Biological Signalling Studies University of Freiburg Freiburg Germany
| | - Anja Stulz
- Department of Pharmaceutical Technology and Biopharmacy University of Freiburg Freiburg Germany
| | - Michael Kaiser
- Department of Pharmaceutical Technology and Biopharmacy University of Freiburg Freiburg Germany
| | - Heiko Heerklotz
- CIBSS ‐ Centre for Integrative Biological Signalling Studies University of Freiburg Freiburg Germany
- Department of Pharmaceutical Technology and Biopharmacy University of Freiburg Freiburg Germany
- Leslie Dan Faculty of Pharmacy University of Toronto Toronto Canada
- BIOSS Centre for Biological Signalling Studies University of Freiburg Freiburg Germany
| | - Carola Hunte
- Institute for Biochemistry and Molecular Biology ZBMZ, Faculty of Medicine University of Freiburg Freiburg Germany
- CIBSS ‐ Centre for Integrative Biological Signalling Studies University of Freiburg Freiburg Germany
- BIOSS Centre for Biological Signalling Studies University of Freiburg Freiburg Germany
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22
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Microdeletion and microduplication of 1p36.11p35.3 involving AHDC1 contribute to neurodevelopmental disorder. Eur J Med Genet 2020; 63:103611. [DOI: 10.1016/j.ejmg.2019.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 11/16/2018] [Accepted: 01/03/2019] [Indexed: 12/18/2022]
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23
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Beaudin M, Matilla-Dueñas A, Soong BW, Pedroso JL, Barsottini OG, Mitoma H, Tsuji S, Schmahmann JD, Manto M, Rouleau GA, Klein C, Dupre N. The Classification of Autosomal Recessive Cerebellar Ataxias: a Consensus Statement from the Society for Research on the Cerebellum and Ataxias Task Force. CEREBELLUM (LONDON, ENGLAND) 2019; 18:1098-1125. [PMID: 31267374 PMCID: PMC6867988 DOI: 10.1007/s12311-019-01052-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
There is currently no accepted classification of autosomal recessive cerebellar ataxias, a group of disorders characterized by important genetic heterogeneity and complex phenotypes. The objective of this task force was to build a consensus on the classification of autosomal recessive ataxias in order to develop a general approach to a patient presenting with ataxia, organize disorders according to clinical presentation, and define this field of research by identifying common pathogenic molecular mechanisms in these disorders. The work of this task force was based on a previously published systematic scoping review of the literature that identified autosomal recessive disorders characterized primarily by cerebellar motor dysfunction and cerebellar degeneration. The task force regrouped 12 international ataxia experts who decided on general orientation and specific issues. We identified 59 disorders that are classified as primary autosomal recessive cerebellar ataxias. For each of these disorders, we present geographical and ethnical specificities along with distinctive clinical and imagery features. These primary recessive ataxias were organized in a clinical and a pathophysiological classification, and we present a general clinical approach to the patient presenting with ataxia. We also identified a list of 48 complex multisystem disorders that are associated with ataxia and should be included in the differential diagnosis of autosomal recessive ataxias. This classification is the result of a consensus among a panel of international experts, and it promotes a unified understanding of autosomal recessive cerebellar disorders for clinicians and researchers.
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Affiliation(s)
- Marie Beaudin
- Axe Neurosciences, CHU de Québec-Université Laval, Québec, QC, Canada
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Antoni Matilla-Dueñas
- Department of Neuroscience, Health Sciences Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain
| | - Bing-Weng Soong
- Department of Neurology, Shuang Ho Hospital and Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan, Republic of China
- National Yang-Ming University School of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Jose Luiz Pedroso
- Ataxia Unit, Department of Neurology, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Orlando G Barsottini
- Ataxia Unit, Department of Neurology, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan
| | - Shoji Tsuji
- The University of Tokyo, Tokyo, Japan
- International University of Health and Welfare, Chiba, Japan
| | - Jeremy D Schmahmann
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mario Manto
- Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000, Charleroi, Belgium
- Service des Neurosciences, UMons, Mons, Belgium
| | | | | | - Nicolas Dupre
- Axe Neurosciences, CHU de Québec-Université Laval, Québec, QC, Canada.
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada.
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24
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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25
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Guissart C, Harrison AN, Benkirane M, Oncel I, Arslan EA, Chassevent AK., Baraῆano K, Larrieu L, Iascone M, Tenconi R, Claustres M, Eroglu-Ertugrul N, Calvas P, Topaloglu H, Molday RS, Koenig M. ATP8A2-related disorders as recessive cerebellar ataxia. J Neurol 2019; 267:203-213. [DOI: 10.1007/s00415-019-09579-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/06/2019] [Accepted: 10/10/2019] [Indexed: 02/03/2023]
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26
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Janzen E, Wolff L, Mendoza-Ferreira N, Hupperich K, Delle Vedove A, Hosseinibarkooie S, Kye MJ, Wirth B. PLS3 Overexpression Delays Ataxia in Chp1 Mutant Mice. Front Neurosci 2019; 13:993. [PMID: 31607845 PMCID: PMC6761326 DOI: 10.3389/fnins.2019.00993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/03/2019] [Indexed: 11/25/2022] Open
Abstract
Many neurodegenerative disorders share common pathogenic pathways such as endocytic defects, Ca2+ misregulation and defects in actin dynamics. Factors acting on these shared pathways are highly interesting as a therapeutic target. Plastin 3 (PLS3), a proven protective modifier of spinal muscular atrophy across species, is a remarkable example of the former, and thereby offers high potential as a cross-disease modifier. Importantly, PLS3 has been linked to numerous proteins associated with various neurodegenerative diseases. Among them, PLS3 directly interacts with calcineurin like EF-hand protein 1 (CHP1), whose loss-of-function results in ataxia. In this study, we aimed to determine whether PLS3 is a cross-disease modifier for ataxia caused by Chp1 mutation in mice. For this purpose, we generated Chp1 mutant mice, named vacillator mice, overexpressing a PLS3 transgene. Here, we show that PLS3 overexpression (OE) delays the ataxic phenotype of the vacillator mice at an early but not later disease stage. Furthermore, we demonstrated that PLS3 OE ameliorates axon hypertrophy and axonal swellings in Purkinje neurons thereby slowing down neurodegeneration. Mechanistically, we found that PLS3 OE in the cerebellum shows a trend of increased membrane targeting and/or expression of Na+/H+ exchanger (NHE1), an important CHP1 binding partner and a causative gene for ataxia, when mutated in humans and mice. This data supports the hypothesis that PLS3 is a cross-disease genetic modifier for CHP1-causing ataxia and spinal muscular atrophy.
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Affiliation(s)
- Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Lisa Wolff
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Kristina Hupperich
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Andrea Delle Vedove
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Min Jeong Kye
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
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27
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Khayat W, Hackett A, Shaw M, Ilie A, Dudding-Byth T, Kalscheuer VM, Christie L, Corbett MA, Juusola J, Friend KL, Kirmse BM, Gecz J, Field M, Orlowski J. A recurrent missense variant in SLC9A7 causes nonsyndromic X-linked intellectual disability with alteration of Golgi acidification and aberrant glycosylation. Hum Mol Genet 2019; 28:598-614. [PMID: 30335141 DOI: 10.1093/hmg/ddy371] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/12/2018] [Indexed: 11/13/2022] Open
Abstract
We report two unrelated families with multigenerational nonsyndromic intellectual disability (ID) segregating with a recurrent de novo missense variant (c.1543C>T:p.Leu515Phe) in the alkali cation/proton exchanger gene SLC9A7 (also commonly referred to as NHE7). SLC9A7 is located on human X chromosome at Xp11.3 and has not yet been associated with a human phenotype. The gene is widely transcribed, but especially abundant in brain, skeletal muscle and various secretory tissues. Within cells, SLC9A7 resides in the Golgi apparatus, with prominent enrichment in the trans-Golgi network (TGN) and post-Golgi vesicles. In transfected Chinese hamster ovary AP-1 cells, the Leu515Phe mutant protein was correctly targeted to the TGN/post-Golgi vesicles, but its N-linked oligosaccharide maturation as well as that of a co-transfected secretory membrane glycoprotein, vesicular stomatitis virus G (VSVG) glycoprotein, was reduced compared to cells co-expressing SLC9A7 wild-type and VSVG. This correlated with alkalinization of the TGN/post-Golgi compartments, suggestive of a gain-of-function. Membrane trafficking of glycosylation-deficient Leu515Phe and co-transfected VSVG to the cell surface, however, was relatively unaffected. Mass spectrometry analysis of patient sera also revealed an abnormal N-glycosylation profile for transferrin, a clinical diagnostic marker for congenital disorders of glycosylation. These data implicate a crucial role for SLC9A7 in the regulation of TGN/post-Golgi pH homeostasis and glycosylation of exported cargo, which may underlie the cellular pathophysiology and neurodevelopmental deficits associated with this particular nonsyndromic form of X-linked ID.
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Affiliation(s)
- Wujood Khayat
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Anna Hackett
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Marie Shaw
- Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | - Alina Ilie
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Tracy Dudding-Byth
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Vera M Kalscheuer
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Louise Christie
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - Mark A Corbett
- Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia
| | | | - Kathryn L Friend
- Genetics and Molecular Pathology, SA Pathology, Adelaide, SA, Australia
| | - Brian M Kirmse
- Department of Pediatrics, Division of Medical Genetics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jozef Gecz
- Adelaide Medical School and Robinson Research Institute, The University of Adelaide, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Michael Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW, Australia
| | - John Orlowski
- Department of Physiology, McGill University, Montreal, Quebec, Canada
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28
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Structural and Functional Changes in the Na +/H + Exchanger Isoform 1, Induced by Erk1/2 Phosphorylation. Int J Mol Sci 2019; 20:ijms20102378. [PMID: 31091671 PMCID: PMC6566726 DOI: 10.3390/ijms20102378] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/15/2022] Open
Abstract
The human Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane transport protein that plays an important role in pH regulation in mammalian cells. Because of the generation of protons by intermediary metabolism as well as the negative membrane potential, protons accumulate within the cytosol. Extracellular signal-regulated kinase (ERK)-mediated regulation of NHE1 is important in several human pathologies including in the myocardium in heart disease, as well as in breast cancer as a trigger for growth and metastasis. NHE1 has a N-terminal, a 500 amino acid membrane domain, and a C-terminal 315 amino acid cytosolic domain. The C-terminal domain regulates the membrane domain and its effects on transport are modified by protein binding and phosphorylation. Here, we discuss the physiological regulation of NHE1 by ERK, with an emphasis on the critical effects on structure and function. ERK binds directly to the cytosolic domain at specific binding domains. ERK also phosphorylates NHE1 directly at multiple sites, which enhance NHE1 activity with subsequent downstream physiological effects. The NHE1 cytosolic regulatory tail possesses both ordered and disordered regions, and the disordered regions are stabilized by ERK-mediated phosphorylation at a phosphorylation motif. Overall, ERK pathway mediated phosphorylation modulates the NHE1 tail, and affects the activity, structure, and function of this membrane protein.
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29
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Fuchs S, Hansen SC, Markones M, Mymrikov EV, Heerklotz H, Hunte C. Calcineurin B homologous protein 3 binds with high affinity to the CHP binding domain of the human sodium/proton exchanger NHE1. Sci Rep 2018; 8:14837. [PMID: 30287853 PMCID: PMC6172220 DOI: 10.1038/s41598-018-33096-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/21/2018] [Indexed: 12/26/2022] Open
Abstract
The Na+/H+ exchanger NHE1 is critical for cell vitality as it controls intracellular pH and cell volume. Its functionality is influenced by calcineurin B homologous proteins (CHPs). The human isoform CHP3 is important for transport of NHE1 to the plasma membrane and for its activity. Here, we characterized the binding interaction of human CHP3 with the regulatory domain of NHE1. The exact binding site of CHP3 was previously debated. CHP3 as well as both regions of NHE1 in question were produced and purified. CHP3 specifically formed stable complexes with the CHP-binding region (CBD) of NHE1 (residues 503-545) in size-exclusion chromatography (SEC), but not with the C-terminal region (CTD, residues 633-815). CTD was functional as shown by Ca2+-dependent binding of calmodulin in SEC analysis. CHP3 bound with high affinity to CBD with an equilibrium dissociation constant (KD) of 56 nM determined by microscale thermophoresis. The high affinity was substantiated by isothermal calorimetry analysis (KD = 3 nM), which also revealed that the interaction with CBD is strongly exothermic (ΔG° = -48.6 kJ/mol, ΔH = -75.3 kJ/mol, -TΔS° = 26.7 kJ/mol). The data provide insights in the molecular mechanisms that underlie the regulatory interaction of CHP3 and NHE1 and more general of calcineurin homologous proteins with their target proteins.
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Affiliation(s)
- Simon Fuchs
- Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, D-79104, Freiburg, Germany
| | - Sierra C Hansen
- Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104, Freiburg, Germany
| | - Marie Markones
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg, D-79104, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Freiburg, Germany
| | - Evgeny V Mymrikov
- Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Freiburg, Germany
| | - Heiko Heerklotz
- Department of Pharmaceutical Technology and Biopharmacy, University of Freiburg, D-79104, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Freiburg, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada
| | - Carola Hunte
- Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104, Freiburg, Germany.
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Freiburg, Germany.
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A novel SLC9A1 mutation causes cerebellar ataxia. J Hum Genet 2018; 63:1049-1054. [DOI: 10.1038/s10038-018-0488-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/08/2018] [Accepted: 07/01/2018] [Indexed: 11/08/2022]
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Mendoza-Ferreira N, Coutelier M, Janzen E, Hosseinibarkooie S, Löhr H, Schneider S, Milbradt J, Karakaya M, Riessland M, Pichlo C, Torres-Benito L, Singleton A, Zuchner S, Brice A, Durr A, Hammerschmidt M, Stevanin G, Wirth B. Biallelic CHP1 mutation causes human autosomal recessive ataxia by impairing NHE1 function. NEUROLOGY-GENETICS 2018; 4:e209. [PMID: 29379881 PMCID: PMC5775069 DOI: 10.1212/nxg.0000000000000209] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 08/22/2017] [Indexed: 12/14/2022]
Abstract
Objective: To ascertain the genetic and functional basis of complex autosomal recessive cerebellar ataxia (ARCA) presented by 2 siblings of a consanguineous family characterized by motor neuropathy, cerebellar atrophy, spastic paraparesis, intellectual disability, and slow ocular saccades. Methods: Combined whole-genome linkage analysis, whole-exome sequencing, and focused screening for identification of potential causative genes were performed. Assessment of the functional consequences of the mutation on protein function via subcellular fractionation, size-exclusion chromatography, and fluorescence microscopy were done. A zebrafish model, using Morpholinos, was generated to study the pathogenic effect of the mutation in vivo. Results: We identified a biallelic 3-bp deletion (p.K19del) in CHP1 that cosegregates with the disease. Neither focused screening for CHP1 variants in 2 cohorts (ARCA: N = 319 and NeurOmics: N = 657) nor interrogating GeneMatcher yielded additional variants, thus revealing the scarcity of CHP1 mutations. We show that mutant CHP1 fails to integrate into functional protein complexes and is prone to aggregation, thereby leading to diminished levels of soluble CHP1 and reduced membrane targeting of NHE1, a major Na+/H+ exchanger implicated in syndromic ataxia-deafness. Chp1 deficiency in zebrafish, resembling the affected individuals, led to movement defects, cerebellar hypoplasia, and motor axon abnormalities, which were ameliorated by coinjection with wild-type, but not mutant, human CHP1 messenger RNA. Conclusions: Collectively, our results identified CHP1 as a novel ataxia-causative gene in humans, further expanding the spectrum of ARCA-associated loci, and corroborated the crucial role of NHE1 within the pathogenesis of these disorders.
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Affiliation(s)
- Natalia Mendoza-Ferreira
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Marie Coutelier
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Eva Janzen
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Heiko Löhr
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Svenja Schneider
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Janine Milbradt
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Mert Karakaya
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Markus Riessland
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Christian Pichlo
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Laura Torres-Benito
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Andrew Singleton
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Stephan Zuchner
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Alexis Brice
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Alexandra Durr
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Matthias Hammerschmidt
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Giovanni Stevanin
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
| | - Brunhilde Wirth
- Institute of Human Genetics (N.M.-F., E.J., S.H., S.S., J.M., M.K., M.R., L.T.-B., B.W.), Center for Molecular Medicine Cologne, Institute for Genetics and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany; Institute for Zoology, Developmental Biology (H.L., M.H.), Institute of Biochemistry (C.P.), University of Cologne, Germany; Institut du Cerveau et de la Moelle épinière (M.C., A.B., A.D., G.S.), INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, France; Ecole Pratique des Hautes Etudes (M.C., G.S.), PSL Research University, Paris, France; Laboratory of Molecular and Cellular Neuroscience (M.R.), The Rockefeller University, New York, NY; Laboratory of Neurogenetics (A.S.), National Institute on Aging, National Institutes of Health, Bethesda, MD; John P. Hussman Institute for Human Genomics (S.Z.), University of Miami, Miller School of Medicine, FL; and APHP (A.B., A.D., G.S.), Hôpital de la Pitié-Salpêtrière, Centre de réference de neurogénétique, Paris, France
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Abstract
The autosomal-recessive cerebellar ataxias comprise more than half of the known genetic forms of ataxia and represent an extensive group of clinically heterogeneous disorders that can occur at any age but whose onset is typically prior to adulthood. In addition to ataxia, patients often present with polyneuropathy and clinical symptoms outside the nervous system. The most common of these diseases is Friedreich ataxia, caused by mutation of the frataxin gene, but recent advances in genetic analysis have greatly broadened the ever-expanding number of causative genes to over 50. In this review, the clinical neurogenetics of the recessive cerebellar ataxias will be discussed, including updates on recently identified novel ataxia genes, advancements in unraveling disease-specific molecular pathogenesis leading to ataxia, potential treatments under development, technologic improvements in diagnostic testing such as clinical exome sequencing, and what the future holds for clinicians and geneticists.
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Affiliation(s)
- Brent L Fogel
- Program in Neurogenetics, Departments of Neurology and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
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Beaudin M, Klein CJ, Rouleau GA, Dupré N. Systematic review of autosomal recessive ataxias and proposal for a classification. CEREBELLUM & ATAXIAS 2017; 4:3. [PMID: 28250961 PMCID: PMC5324265 DOI: 10.1186/s40673-017-0061-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/17/2017] [Indexed: 01/26/2023]
Abstract
Background The classification of autosomal recessive ataxias represents a significant challenge because of high genetic heterogeneity and complex phenotypes. We conducted a comprehensive systematic review of the literature to examine all recessive ataxias in order to propose a new classification and properly circumscribe this field as new technologies are emerging for comprehensive targeted gene testing. Methods We searched Pubmed and Embase to identify original articles on recessive forms of ataxia in humans for which a causative gene had been identified. Reference lists and public databases, including OMIM and GeneReviews, were also reviewed. We evaluated the clinical descriptions to determine if ataxia was a core feature of the phenotype and assessed the available evidence on the genotype-phenotype association. Included disorders were classified as primary recessive ataxias, as other complex movement or multisystem disorders with prominent ataxia, or as disorders that may occasionally present with ataxia. Results After removal of duplicates, 2354 references were reviewed and assessed for inclusion. A total of 130 articles were completely reviewed and included in this qualitative analysis. The proposed new list of autosomal recessive ataxias includes 45 gene-defined disorders for which ataxia is a core presenting feature. We propose a clinical algorithm based on the associated symptoms. Conclusion We present a new classification for autosomal recessive ataxias that brings awareness to their complex phenotypes while providing a unified categorization of this group of disorders. This review should assist in the development of a consensus nomenclature useful in both clinical and research applications. Electronic supplementary material The online version of this article (doi:10.1186/s40673-017-0061-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marie Beaudin
- Faculty of Medicine, Université Laval, Quebec city, QC G1V 0A6 Canada
| | | | - Guy A Rouleau
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 1A4 Canada
| | - Nicolas Dupré
- Faculty of Medicine, Université Laval, Quebec city, QC G1V 0A6 Canada.,Department of Neurological Sciences, CHU de Quebec - Université Laval, 1401 18th street, Québec City, QC G1J 1Z4 Canada
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Li X, Augustine A, Chen S, Fliegel L. Stop Codon Polymorphisms in the Human SLC9A1 Gene Disrupt or Compromise Na+/H+ Exchanger Function. PLoS One 2016; 11:e0162902. [PMID: 27636896 PMCID: PMC5026351 DOI: 10.1371/journal.pone.0162902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/30/2016] [Indexed: 11/18/2022] Open
Abstract
The NHE1 isoform of the mammalian Na+/H+ exchanger is a ubiquitous plasma membrane protein that regulates intracellular pH in mammalian cells by removing one intracellular proton in exchange for one extracellular sodium. Deletion of the NHE1 gene (SLC9A1) affects the growth and motor ability of mice and humans but mutations and polymorphisms of the gene are only beginning to be characterized. NHE1 has a cytosolic C-terminal regulatory tail of approximately 315 amino acids and a 500 amino acid membrane domain. We examined the functional effects of three human stop codon mutations at amino acids 321, 449 and 735 in comparison with a mutant that had a shortened tail region (543 stop codon). The short mutants, 321, 449 and 543 stop codon mutant proteins, lost NHE1 activity and expression, and did not target to the plasma membrane. Protein for these short mutants was more rapidly degraded than the wild type and 735 ending proteins. The 735 terminating mutant, with the membrane domain and much of the cytosolic tail, had reduced protein expression and activity. The results demonstrate that early stop codon polymorphisms have significant and deleterious effects on the activity of the SLC9A1 protein product. The 735-NHE1 mutant, without the last 80 amino acids, had more minor defects. Surprisingly, retention of a proximal 43 amino acids adjacent to the membrane domain did little to maintain NHE1 expression, targeting and activity.
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Affiliation(s)
- Xiuju Li
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
| | - Aruna Augustine
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
| | - Shuo Chen
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
| | - Larry Fliegel
- Department of Biochemistry, University Alberta, Edmonton, AB T6G 2H7, Canada
- * E-mail:
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Liu Y, Basu A, Li X, Fliegel L. Topological analysis of the Na+/H+ exchanger. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015. [DOI: 10.1016/j.bbamem.2015.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Li X, Fliegel L. A novel human mutation in the SLC9A1 gene results in abolition of Na+/H+ exchanger activity. PLoS One 2015; 10:e0119453. [PMID: 25760855 PMCID: PMC4356549 DOI: 10.1371/journal.pone.0119453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/06/2015] [Indexed: 11/19/2022] Open
Abstract
The SLC9A1 gene, the Na+/H+ exchanger isoform 1 is the principal plasma membrane Na+/H+ exchanger of mammalian cells and functions by exchanging one intracellular proton for one extracellular sodium. The human protein is 815 amino acids in length. Five hundred N-terminal amino acids make up the transport domain of the protein and are believed to form 12 transmembrane segments. Recently, a genetic mutation of the Na+/H+ exchanger isoform 1, N266H, was discovered in a human patient through exome sequencing. We examined the effect of this mutation on expression, targeting and activity of the Na+/H+ exchanger. Mutant N266H protein was expressed in AP-1 cells, which lack their endogenous Na+/H+ exchanger protein. Targeting of the mutant protein to the cell surface was normal and expression levels were only slightly reduced relative to the wild type protein. However, the N266H mutant protein had no detectable Na+/H+ exchanger activity. A histidine residue at this location may disrupt the cation binding site or the pore of the Na+/H+ exchanger protein.
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Affiliation(s)
- Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Na+-H+ exchanger-1 (NHE1) regulation in kidney proximal tubule. Cell Mol Life Sci 2015; 72:2061-74. [PMID: 25680790 DOI: 10.1007/s00018-015-1848-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 01/17/2023]
Abstract
The ubiquitously expressed plasma membrane Na(+)-H(+) exchanger NHE1 is a 12 transmembrane-spanning protein that directs important cell functions such as homeostatic intracellular volume and pH control. The 315 amino acid cytosolic tail of NHE1 binds plasma membrane phospholipids and multiple proteins that regulate additional, ion-translocation independent functions. This review focuses on NHE1 structure/function relationships, as well as the role of NHE1 in kidney proximal tubule functions, including pH regulation, vectorial Na(+) transport, cell volume control and cell survival. The implications of these functions are particularly critical in the setting of progressive, albuminuric kidney diseases, where the accumulation of reabsorbed fatty acids leads to disruption of NHE1-membrane phospholipid interactions and tubular atrophy, which is a poor prognostic factor for progression to end stage renal disease. This review amplifies the vital role of the proximal tubule NHE1 Na(+)-H(+) exchanger as a kidney cell survival factor.
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