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Bae HG, Wu WC, Nip K, Gould E, Kim JH. Scn2a deletion disrupts oligodendroglia function: Implication for myelination, neural circuitry, and auditory hypersensitivity in ASD. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589242. [PMID: 38659965 PMCID: PMC11042360 DOI: 10.1101/2024.04.15.589242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Autism spectrum disorder (ASD) is characterized by a complex etiology, with genetic determinants significantly influencing its manifestation. Among these, the Scn2a gene emerges as a pivotal player, crucially involved in both glial and neuronal functionality. This study elucidates the underexplored roles of Scn2a in oligodendrocytes, and its subsequent impact on myelination and auditory neural processes. The results reveal a nuanced interplay between oligodendrocytes and axons, where Scn2a deletion causes alterations in the intricate process of myelination. This disruption, in turn, instigates changes in axonal properties and neuronal activities at the single cell level. Furthermore, oligodendrocyte-specific Scn2a deletion compromises the integrity of neural circuitry within auditory pathways, leading to auditory hypersensitivity-a common sensory abnormality observed in ASD. Through transcriptional profiling, we identified alterations in the expression of myelin-associated genes, highlighting the cellular consequences engendered by Scn2a deletion. In summary, the findings provide unprecedented insights into the pathway from Scn2a deletion in oligodendrocytes to sensory abnormalities in ASD, underscoring the integral role of Scn2a -mediated myelination in auditory responses. This research thereby provides novel insights into the intricate tapestry of genetic and cellular interactions inherent in ASD.
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Cipriani S, Guerrero-Valero M, Tozza S, Zhao E, Vollmer V, Beijer D, Danzi M, Rivellini C, Lazarevic D, Pipitone GB, Grosz BR, Lamperti C, Marzoli SB, Carrera P, Devoto M, Pisciotta C, Pareyson D, Kennerson M, Previtali SC, Zuchner S, Scherer SS, Manganelli F, Bähler M, Bolino A. Mutations in MYO9B are associated with Charcot-Marie-Tooth disease type 2 neuropathies and isolated optic atrophy. Eur J Neurol 2023; 30:511-526. [PMID: 36260368 PMCID: PMC10099703 DOI: 10.1111/ene.15601] [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: 10/04/2022] [Accepted: 10/11/2022] [Indexed: 01/20/2023]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders caused by mutations in at least 100 genes. However, approximately 60% of cases with axonal neuropathies (CMT2) still remain without a genetic diagnosis. We aimed at identifying novel disease genes responsible for CMT2. METHODS We performed whole exome sequencing and targeted next generation sequencing panel analyses on a cohort of CMT2 families with evidence for autosomal recessive inheritance. We also performed functional studies to explore the pathogenetic role of selected variants. RESULTS We identified rare, recessive variants in the MYO9B (myosin IX) gene in two families with CMT2. MYO9B has not yet been associated with a human disease. MYO9B is an unconventional single-headed processive myosin motor protein with signaling properties, and, consistent with this, our results indicate that a variant occurring in the MYO9B motor domain impairs protein expression level and motor activity. Interestingly, a Myo9b-null mouse has degenerating axons in sciatic nerves and optic nerves, indicating that MYO9B plays an essential role in both peripheral nervous system and central nervous system axons, respectively. The degeneration observed in the optic nerve prompted us to screen for MYO9B mutations in a cohort of patients with optic atrophy (OA). Consistent with this, we found compound heterozygous variants in one case with isolated OA. CONCLUSIONS Novel or very rare variants in MYO9B are associated with CMT2 and isolated OA.
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Affiliation(s)
- Silvia Cipriani
- Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marta Guerrero-Valero
- Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stefano Tozza
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
| | - Edward Zhao
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Biostatistics, University of Washington, Seattle, Washington, USA
| | - Veith Vollmer
- Institute of Integrative Cell Biology and Physiology, Westfalian Wilhelms University Münster, Münster, Germany
| | - Danique Beijer
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, Florida, USA
| | - Matt Danzi
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, Florida, USA
| | - Cristina Rivellini
- Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Dejan Lazarevic
- Center for Omics Sciences, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Giovanni Battista Pipitone
- Unit of Genomics for the Diagnosis of Human Pathologies and Laboratory of Clinical and Molecular Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Bianca Rose Grosz
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney Local Health District and Faculty of Health and Medicine, University of Sydney, Sydney, Australia
| | - Costanza Lamperti
- Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefania Bianchi Marzoli
- Neuroophthalmology Service and Ocular Electrophysiology laboratory, Department of Ophthalmology, Scientific Institute, Auxologico Capitanio Hospital, Milan, Italy
| | - Paola Carrera
- Unit of Genomics for the Diagnosis of Human Pathologies and Laboratory of Clinical and Molecular Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marcella Devoto
- Division of Genetics, Children's Hospital of Philadelphia, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- CNR-IRGB, Cagliari, Italy
| | - Chiara Pisciotta
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Department of Clinical Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marina Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute Sydney Local Health District and Faculty of Health and Medicine, University of Sydney, Sydney, Australia
| | - Stefano C Previtali
- Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
- Department of Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stephan Zuchner
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami, Miami, Florida, USA
| | - Steven S Scherer
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples Federico II, Naples, Italy
| | - Martin Bähler
- Institute of Integrative Cell Biology and Physiology, Westfalian Wilhelms University Münster, Münster, Germany
| | - Alessandra Bolino
- Division of Neuroscience, Institute of Experimental Neurology, IRCCS Ospedale San Raffaele, Milan, Italy
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3
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Munday RM, Haque R, Jan NJ, Wojcik GL, Marie C, Duchen D, Mentzer AJ, Nayak U, Korpe P, Kirkpatrick BD, Petri WA, Duggal P. Genome-Wide Association Study of Campylobacter -Positive Diarrhea Identifies Genes Involved in Toxin Processing and Inflammatory Response. mBio 2022; 13:e0055622. [PMID: 35420468 PMCID: PMC9239263 DOI: 10.1128/mbio.00556-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/14/2022] [Indexed: 12/04/2022] Open
Abstract
Diarrhea is responsible for the deaths of more than 500,000 children each year, many of whom reside in low-to-middle-income countries (LMICs). Additionally, children with multiple diarrheal infections early in life have increased growth stunting and malnutrition and decreased vaccine efficacy. Two bacteria that contribute to the burden of diarrhea are Campylobacter jejuni and Campylobacter coli, both are endemic in Bangladesh. However, not all children that are exposed to these pathogens, including Campylobacter, will experience diarrhea. We hypothesized that host genetics may influence susceptibility to Campylobacter infections and performed a genome-wide association study in 534 children from two independent birth cohorts in Dhaka, Bangladesh. Infants were monitored for diarrhea for the first 2 years of life and only defined as controls if all diarrheal samples in the first year were negative for Campylobacter jejuni/C. coli. Each cohort was analyzed separately under an additive model and adjusted for length-for-age z-scores at birth and 12 months, sex, water treatment, and ancestry. In a fixed effect inverse-variance weighted meta-analysis of these two cohorts, we identified a genome-wide significant region on chromosome 8 in intron 4 of the rho guanine nucleotide exchange factor 10 gene (ARHGEF10). Individuals with the G allele (rs13281104) had a 2-fold lower risk of having a Campylobacter-associated diarrheal episode than individuals with the A allele (OR 0.41, 95% CI 0.29 to 0.58, P = 3.6 × 10-7). This SNP is associated with decreased expression of the neighboring gene, CLN8, which may be involved in the transport of the cytolethal distending toxin produced by Campylobacter. IMPORTANCE Children in low-to-middle-income countries often suffer from multiple enteric infections in their first few years of life, many of which have the potential for long-lasting effects. These children are already likely to be malnourished and underweight, and chronic intestinal disturbances exacerbate these conditions. Despite public health interventions aimed at improving water, sanitation, and hygiene, enteric infections are still a leading cause of death for children under five. Previous work has included transmission dynamics, pathogen characteristics, and evaluation of interventions. Here, we examined the role of host genetic variation in susceptibility to diarrhea-associated Campylobacter infection. In our meta-analysis of two independent birth cohorts from Dhaka, Bangladesh, we found that children carrying a specific genetic variant (rs13281104, in an intron of ARHGEF10) were half as likely to have a diarrhea-associated Campylobacter infection in their first year of life. This protective effect may be achieved by decreasing gene expression and thereby impacting host-pathogen interactions and host immune response.
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Affiliation(s)
- Rebecca M. Munday
- Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Ning-Jiun Jan
- Department of Medicine, Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Genevieve L. Wojcik
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Chelsea Marie
- Department of Medicine, Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Dylan Duchen
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Alexander J. Mentzer
- The Wellcome Centre for Human Genetics, University of Oxford, Oxford, Oxfordshire, UK
| | - Uma Nayak
- Center for Public Health Genomics and Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Poonum Korpe
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Beth D. Kirkpatrick
- University of Vermont College of Medicine and Vaccine Testing Center, Burlington, Vermont, USA
| | - William A. Petri
- Department of Medicine, Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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4
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Dysregulation of myelin synthesis and actomyosin function underlies aberrant myelin in CMT4B1 neuropathy. Proc Natl Acad Sci U S A 2021; 118:2009469118. [PMID: 33653949 DOI: 10.1073/pnas.2009469118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Charcot-Marie-Tooth type 4B1 (CMT4B1) is a severe autosomal recessive demyelinating neuropathy with childhood onset, caused by loss-of-function mutations in the myotubularin-related 2 (MTMR2) gene. MTMR2 is a ubiquitously expressed catalytically active 3-phosphatase, which in vitro dephosphorylates the 3-phosphoinositides PtdIns3P and PtdIns(3,5)P 2, with a preference for PtdIns(3,5)P 2 A hallmark of CMT4B1 neuropathy are redundant loops of myelin in the nerve termed myelin outfoldings, which can be considered the consequence of altered growth of myelinated fibers during postnatal development. How MTMR2 loss and the resulting imbalance of 3'-phosphoinositides cause CMT4B1 is unknown. Here we show that MTMR2 by regulating PtdIns(3,5)P 2 levels coordinates mTORC1-dependent myelin synthesis and RhoA/myosin II-dependent cytoskeletal dynamics to promote myelin membrane expansion and longitudinal myelin growth. Consistent with this, pharmacological inhibition of PtdIns(3,5)P 2 synthesis or mTORC1/RhoA signaling ameliorates CMT4B1 phenotypes. Our data reveal a crucial role for MTMR2-regulated lipid turnover to titrate mTORC1 and RhoA signaling thereby controlling myelin growth.
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Yechieli M, Gulsuner S, Ben-Pazi H, Fattal A, Aran A, Kuzminsky A, Sagi L, Guttman D, Schneebaum Sender N, Gross-Tsur V, Klopstock T, Walsh T, Renbaum P, Zeligson S, Shemer Meiri L, Lev D, Shmueli D, Blumkin L, Lahad A, King MC, Levy EL, Segel R. Diagnostic yield of chromosomal microarray and trio whole exome sequencing in cryptogenic cerebral palsy. J Med Genet 2021; 59:759-767. [PMID: 34321325 DOI: 10.1136/jmedgenet-2021-107884] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 07/14/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To determine the yield of genetic diagnoses using chromosomal microarray (CMA) and trio whole exome sequencing (WES), separately and combined, among patients with cryptogenic cerebral palsy (CP). METHODS Trio WES of patients with prior CMA analysis for cryptogenic CP, defined as disabling, non-progressive motor symptoms beginning before the age of 3 years without known cause. RESULTS Given both CMA analysis and trio WES, clinically significant genetic findings were identified for 58% of patients (26 of 45). Diagnoses were eight large CNVs detected by CMA and 18 point mutations detected by trio WES. None had more than one severe mutation. Approximately half of events (14 of 26) were de novo. Yield was significantly higher in patients with CP with comorbidities (69%, 22 of 32) than in those with pure motor CP (31%, 4 of 13; p=0.02). Among patients with genetic diagnoses, CNVs were more frequent than point mutations among patients with congenital anomalies (OR 7.8, 95% CI 1.2 to 52.4) or major dysmorphic features (OR 10.5, 95% CI 1.4 to 73.7). Clinically significant mutations were identified in 18 different genes: 14 with known involvement in CP-related disorders and 4 responsible for other neurodevelopmental conditions. Three possible new candidate genes for CP were ARGEF10, RTF1 and TAOK3. CONCLUSIONS Cryptogenic CP is genetically highly heterogeneous. Genomic analysis has a high yield and is warranted in all these patients. Trio WES has higher yield than CMA, except in patients with congenital anomalies or major dysmorphic features, but these methods are complementary. Patients with negative results with one approach should also be tested by the other.
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Affiliation(s)
- Michal Yechieli
- Obstetrics and Gynecology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Suleyman Gulsuner
- Department of Medicine and Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Hilla Ben-Pazi
- Pediatric Neurology, Shaare Zedek Medical Center, Jerusalem, Israel.,Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aviva Fattal
- Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adi Aran
- Pediatric Neurology, Shaare Zedek Medical Center, Jerusalem, Israel.,Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alla Kuzminsky
- Pediatric Neurology Institute, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
| | - Liora Sagi
- Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dafna Guttman
- Pediatric Rehabilitation Department, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Israel
| | - Nira Schneebaum Sender
- Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Varda Gross-Tsur
- Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.,Pediatric Neurology Unit, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Tehila Klopstock
- Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.,Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Tom Walsh
- Department of Medicine and Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Paul Renbaum
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Sharon Zeligson
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | | | - Dorit Lev
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Institute of Medical Genetics, Edith Wolfson Medical Center, Holon, Israel
| | - Dorit Shmueli
- Child Development Services, Clalit Health Services, Tel Aviv, Israel
| | - Luba Blumkin
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Neurology, Edith Wolfson Hospital, Holon, Israel
| | - Amnon Lahad
- Braun School of Public Health, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Family Medicine, Clalit Health Services, Jerusalem, Israel
| | - Mary-Claire King
- Department of Medicine and Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Ephrat Lahad Levy
- Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.,Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Reeval Segel
- Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel .,Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
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Catusi I, Garzo M, Capra AP, Briuglia S, Baldo C, Canevini MP, Cantone R, Elia F, Forzano F, Galesi O, Grosso E, Malacarne M, Peron A, Romano C, Saccani M, Larizza L, Recalcati MP. 8p23.2-pter Microdeletions: Seven New Cases Narrowing the Candidate Region and Review of the Literature. Genes (Basel) 2021; 12:genes12050652. [PMID: 33925474 PMCID: PMC8146486 DOI: 10.3390/genes12050652] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 12/11/2022] Open
Abstract
To date only five patients with 8p23.2-pter microdeletions manifesting a mild-to-moderate cognitive impairment and/or developmental delay, dysmorphisms and neurobehavioral issues were reported. The smallest microdeletion described by Wu in 2010 suggested a critical region (CR) of 2.1 Mb including several genes, out of which FBXO25, DLGAP2, CLN8, ARHGEF10 and MYOM2 are the main candidates. Here we present seven additional patients with 8p23.2-pter microdeletions, ranging from 71.79 kb to 4.55 Mb. The review of five previously reported and nine Decipher patients confirmed the association of the CR with a variable clinical phenotype characterized by intellectual disability/developmental delay, including language and speech delay and/or motor impairment, behavioral anomalies, autism spectrum disorder, dysmorphisms, microcephaly, fingers/toes anomalies and epilepsy. Genotype analysis allowed to narrow down the 8p23.3 candidate region which includes only DLGAP2, CLN8 and ARHGEF10 genes, accounting for the main signs of the broad clinical phenotype associated to 8p23.2-pter microdeletions. This region is more restricted compared to the previously proposed CR. Overall, our data favor the hypothesis that DLGAP2 is the actual strongest candidate for neurodevelopmental/behavioral phenotypes. Additional patients will be necessary to validate the pathogenic role of DLGAP2 and better define how the two contiguous genes, ARHGEF10 and CLN8, might contribute to the clinical phenotype.
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Affiliation(s)
- Ilaria Catusi
- Istituto Auxologico Italiano, IRCCS, Laboratory of Medical Cytogenetics and Molecular Genetics, 20145 Milan, Italy
| | - Maria Garzo
- Istituto Auxologico Italiano, IRCCS, Laboratory of Medical Cytogenetics and Molecular Genetics, 20145 Milan, Italy
| | - Anna Paola Capra
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, 98100 Messina, Italy
| | - Silvana Briuglia
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, 98100 Messina, Italy
| | - Chiara Baldo
- UOC Laboratorio di Genetica Umana, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Maria Paola Canevini
- Child Neuropsychiatry Unit-Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, 20142 Milan, Italy
| | - Rachele Cantone
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, 10126 Turin, Italy
| | - Flaviana Elia
- Unit of Psychology, Oasi Research Institute-IRCCS, 94018 Troina, Italy
| | - Francesca Forzano
- Clinical Genetics Department, Guy's & St Thomas' NHS Foundation Trust, London SE1 9RT, UK
| | - Ornella Galesi
- Laboratory of Medical Genetics, Oasi Research Institute-IRCCS, 94018 Troina, Italy
| | - Enrico Grosso
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, 10126 Turin, Italy
| | - Michela Malacarne
- UOC Laboratorio di Genetica Umana, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
| | - Angela Peron
- Child Neuropsychiatry Unit-Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, 20142 Milan, Italy
- Human Pathology and Medical Genetics, ASST Santi Paolo e Carlo, San Paolo Hospital, 20142 Milan, Italy
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Corrado Romano
- Unit of Pediatrics and Medical Genetics, Oasi Research Institute-IRCCS, 94018 Troina, Italy
| | - Monica Saccani
- Child Neuropsychiatry Unit-Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, 20142 Milan, Italy
| | - Lidia Larizza
- Istituto Auxologico Italiano, IRCCS, Laboratory of Medical Cytogenetics and Molecular Genetics, 20145 Milan, Italy
| | - Maria Paola Recalcati
- Istituto Auxologico Italiano, IRCCS, Laboratory of Medical Cytogenetics and Molecular Genetics, 20145 Milan, Italy
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7
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Neuropathy-causing TRPV4 mutations disrupt TRPV4-RhoA interactions and impair neurite extension. Nat Commun 2021; 12:1444. [PMID: 33664271 PMCID: PMC7933254 DOI: 10.1038/s41467-021-21699-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 02/02/2021] [Indexed: 12/19/2022] Open
Abstract
TRPV4 is a cell surface-expressed calcium-permeable cation channel that mediates cell-specific effects on cellular morphology and function. Dominant missense mutations of TRPV4 cause distinct, tissue-specific diseases, but the pathogenic mechanisms are unknown. Mutations causing peripheral neuropathy localize to the intracellular N-terminal domain whereas skeletal dysplasia mutations are in multiple domains. Using an unbiased screen, we identified the cytoskeletal remodeling GTPase RhoA as a TRPV4 interactor. TRPV4-RhoA binding occurs via the TRPV4 N-terminal domain, resulting in suppression of TRPV4 channel activity, inhibition of RhoA activation, and extension of neurites in vitro. Neuropathy but not skeletal dysplasia mutations disrupt TRPV4-RhoA binding and cytoskeletal outgrowth. However, inhibition of RhoA restores neurite length in vitro and in a fly model of TRPV4 neuropathy. Together these results identify RhoA as a critical mediator of TRPV4-induced cell structure changes and suggest that disruption of TRPV4-RhoA binding may contribute to tissue-specific toxicity of TRPV4 neuropathy mutations. TRPV4 dominant mutations cause neuropathy. Here, the authors show that TRPV4 binds and interacts with RhoA, modulating the actin cytoskeleton. Neuropathy-causing mutations of TRPV4 disrupt this complex, leading to RhoA activation and impairment of neurite extension in cultured cells and flies.
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8
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Sugiyama T, Yamamoto H, Kon T, Chaya T, Omori Y, Suzuki Y, Abe K, Watanabe D, Furukawa T. The potential role of Arhgef33 RhoGEF in foveal development in the zebra finch retina. Sci Rep 2020; 10:21450. [PMID: 33293601 PMCID: PMC7722920 DOI: 10.1038/s41598-020-78452-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/17/2020] [Indexed: 01/11/2023] Open
Abstract
The fovea is a pit formed in the center of the retina that enables high-acuity vision in certain vertebrate species. While formation of the fovea fascinates many researchers, the molecular mechanisms underlying foveal development are poorly understood. In the current study, we histologically investigated foveal development in zebra finch (Taeniopygia guttata) and found that foveal pit formation begins just before post-hatch day 14 (P14). We next performed RNA-seq analysis to compare gene expression profiles between the central (foveal and parafoveal) and peripheral retina in zebra finch at P14. We found that the Arhgef33 expression is enriched in the middle layer of the inner nuclear layer at the parafovea, suggesting that Arhgef33 is dominantly expressed in Müller glial cells in the developing parafovea. We then performed a pull-down assay using Rhotekin-RBD and observed GEF activity of Arhgef33 against RhoA. We found that overexpression of Arhgef33 in HEK293 cells induces cell contraction and that Arhgef33 expression inhibits neurite extension in Neuro 2A cells, which is partially recovered by a Rho-kinase (ROCK) inhibitor. Taken together, we used zebra finch as a model animal to investigate foveal development and identified Arhgef33 as a candidate protein possibly involved in foveal development through modulating RhoA activity.
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Affiliation(s)
- Takefumi Sugiyama
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Haruka Yamamoto
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tetsuo Kon
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Taro Chaya
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Omori
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8562, Japan
| | - Kentaro Abe
- Laboratory of Brain Development, Graduate School of Life Sciences, Tohoku University, Miyagi, 980-8577, Japan.,Department of Biological Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Dai Watanabe
- Department of Biological Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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9
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Chen Y, Fang F, Kidwell KM, Vangipuram K, Marcath LA, Gersch CL, Rae JM, Hayes DF, Lavoie Smith EM, Henry NL, Beutler AS, Hertz DL. Genetic variation in Charcot-Marie-Tooth genes contributes to sensitivity to paclitaxel-induced peripheral neuropathy. Pharmacogenomics 2020; 21:841-851. [PMID: 32700628 DOI: 10.2217/pgs-2020-0053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Aim: This study explored whether inherited variants in genes causing the hereditary neuropathy condition Charcot-Marie-Tooth disease are associated with sensitivity to paclitaxel-induced peripheral neuropathy (PN). Patients & methods: Hereditary neuropathy genes previously associated with risk of paclitaxel-induced PN were sequenced in paclitaxel-treated patients. Eight putative genetic predictors in five hereditary neuropathy genes (ARHGEF10, SBF2, FGD4, FZD3 and NXN) were tested for association with PN sensitivity after accounting for systemic exposure and clinical variables. Results: FZD3 rs7833751, a proxy for rs7001034, decreased PN sensitivity (additive model, β = -0.41; 95% CI: -0.66 to -0.17; p = 0.0011). None of the other genetic predictors were associated with PN sensitivity. Conclusion: Our results support prior evidence that FZD3 rs7001034 is protective of PN and may be useful for individualizing paclitaxel treatment to prevent PN.
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Affiliation(s)
- Yongzhen Chen
- College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Fang Fang
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA
| | - Kelley M Kidwell
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA.,University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109
| | - Kiran Vangipuram
- Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, MI 48109, USA
| | - Lauren A Marcath
- Department of Pharmacotherapy, Washington State University College of Pharmacy & Pharmaceutical Sciences, Pullman, WA 99164, USA
| | - Christina L Gersch
- University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109.,Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - James M Rae
- University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109.,Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Daniel F Hayes
- University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109.,Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Ellen M Lavoie Smith
- Department of Health Behavior & Biological Sciences, University of Michigan School of Nursing, Ann Arbor, MI 48109, USA
| | - N Lynn Henry
- University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109.,Department of Internal Medicine, Division of Oncology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Andreas S Beutler
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55902, USA.,Department of Oncology, Mayo Clinic, Rochester, MN 55902, USA
| | - Daniel L Hertz
- University of Michigan Rogel Cancer Center, Ann Arbor, MI 48109.,Department of Clinical Pharmacy, University of Michigan College of Pharmacy, Ann Arbor, MI 48109, USA
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10
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Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics. Cells 2020; 9:cells9040835. [PMID: 32244264 PMCID: PMC7226772 DOI: 10.3390/cells9040835] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/22/2020] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed.
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11
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Diaz PL, Furfari A, Wan BA, Lam H, Charames G, Drost L, Fefekos A, Ohearn S, Blake A, Asthana R, Chow E, DeAngelis C. Predictive biomarkers of chemotherapy-induced peripheral neuropathy: a review. Biomark Med 2018; 12:907-916. [DOI: 10.2217/bmm-2017-0427] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of taxane treatment during chemotherapy. Identifying predictive biomarkers of CIPN would allow physicians to alter treatment given to patients according to a personal risk of developing this condition. The current literature on CIPN biomarkers is reviewed, identifying biomarkers which have been found to be significantly related to CIPN. Three genetic biomarkers are identified (ARHGEF10 rs9657362, CYP2C8 rs11572080/rs10509681 and FGD4 rs10771973) which have been found to act as predictive CIPN biomarkers in multiple studies. Possible mechanisms underlying the relationship between these single nucleotide polymorphisms and CIPN development are explored. The biomarkers identified in this study should be investigated further to generate predictive biomarkers that may be used in a clinical setting.
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Affiliation(s)
- Patrick L Diaz
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - Anthony Furfari
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - Bo Angela Wan
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - Henry Lam
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - George Charames
- Pathology & Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
- Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
- Mount Sinai Services Inc., Toronto, Ontario, M5G 1X5, Canada
- Lunenfeld–Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Leah Drost
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | | | | | - Alexia Blake
- MedReleaf Inc., Markham, Ontario, L3R 6G4, Canada
| | - Rashi Asthana
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - Edward Chow
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
| | - Carlo DeAngelis
- Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, M4N 3M5, Canada
- Department of Pharmacy, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, M4N 3M5, Canada
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12
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Lu DH, Hsu CC, Huang SW, Tu HJ, Huang TF, Liou HC, Liao HM, Chen CH, Fu WM, Gau SSF. ARHGEF10 knockout inhibits platelet aggregation and protects mice from thrombus formation. J Thromb Haemost 2017; 15:2053-2064. [PMID: 28799234 DOI: 10.1111/jth.13799] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Indexed: 11/28/2022]
Abstract
Essentials ARHGEF10 single-nucleotide polymorphism provides risk of ischemic and atherothrombotic stroke. The role of ARHGEF10 in platelet function was examined using ARHGEF10 knockout mice. ARHGEF10 deficiency inhibits platelet function and arterial thrombus formation. ARHGEF10 knockout protects mice from stroke-induced infarction. SUMMARY Background ARHGEF10, a member of the Rho guanine nucleotide exchange factor (GEF) family, stimulates Rho GTPases. Rho GTPases have been reported to regulate a variety of cellular behaviors, such as cell polarity, cytoskeletal organization, and gene transcription. ARHGEF10 single-nucleotide polymorphisms are linked to the risk of ischemic stroke. However, the role of ARHGEF10 in platelet function remains unknown. Objective To examine the role of ARHGEF10 in platelet function. Methods ARHGEF10-/- were generated. We examined the in vitro and in vivo effects of ARHGEF10 knockout on platelet function and arterial thrombosis formation. Results ARHGEF10-/- mice had normal platelet counts, but showed altered aggregation in response to thrombin, collagen, ADP, protease-activated receptor-4 peptide, and U46619 stimulation. ARHGEF10 knockout influenced platelet spreading on fibrinogen-coated surfaces, and caused the platelets to show less lamellipodia-like extension than wild-type platelets. ARHGEF10 knockout also inhibited platelet clot retraction induced by thrombin stimulation. ARHGEF10 knockout resulted in prolonged tail bleeding time and inhibited the stable thrombus formation induced by FeCl3 in the carotid artery. Conclusions ARHGEF10 serves as an important regulator in platelet shape change, spreading, and aggregation. Moreover, ARHGEF10 also plays an important role in arterial thrombosis formation.
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Affiliation(s)
- D-H Lu
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - C-C Hsu
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Botanicals, Medical and Pharmaceutical Industry Technology and Development Center, Taipei, Taiwan
| | - S-W Huang
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - H-J Tu
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - T-F Huang
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - H-C Liou
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - H-M Liao
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - C-H Chen
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
- Department and Graduate Institute of Biomedical Sciences, Chang Gung University, Taipei, Taiwan
| | - W-M Fu
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - S S-F Gau
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
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13
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Shibata S, Teshima Y, Niimi K, Inagaki S. Involvement of ARHGEF10, GEF for RhoA, in Rab6/Rab8-mediating membrane traffic. Small GTPases 2017; 10:169-177. [PMID: 28448737 DOI: 10.1080/21541248.2017.1302550] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Small GTPases play crucial roles in the maintenance of a homeostatic environment and appropriate movements of the cell. In these processes, the direct or indirect interaction between distinct small GTPases could be required for regulating mutual signaling pathways. In our recent study, ARHGEF10, known as a guanine nucleotide exchange factor (GEF) for RhoA, was indicated to interact with Rab6A and Rab8A, which are known to function in the exocytotic pathway, and colocalized with these Rabs at exocytotic vesicles. Moreover, it was suggested that ARHGEF10 is involved in the regulation of Rab6A and Rab8A localization and invasion of breast carcinoma cells, in which Rab8 also acts via regulation of membrane trafficking. These results may reveal the existence of a novel small GTPase cascade which connects the signaling of these Rabs with RhoA during membrane trafficking. In this mini-review, we consider the possible functions of ARHGEF10 and RhoA in the Rab6- and Rab8-mediated membrane trafficking pathway.
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Affiliation(s)
- Satoshi Shibata
- a Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine , Osaka University , Osaka , Japan
| | - Yui Teshima
- a Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine , Osaka University , Osaka , Japan
| | - Kenta Niimi
- a Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine , Osaka University , Osaka , Japan
| | - Shinobu Inagaki
- a Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine , Osaka University , Osaka , Japan
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14
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Apellániz-Ruiz M, Tejero H, Inglada-Pérez L, Sánchez-Barroso L, Gutiérrez-Gutiérrez G, Calvo I, Castelo B, Redondo A, García-Donás J, Romero-Laorden N, Sereno M, Merino M, Currás-Freixes M, Montero-Conde C, Mancikova V, Åvall-Lundqvist E, Green H, Al-Shahrour F, Cascón A, Robledo M, Rodríguez-Antona C. Targeted Sequencing Reveals Low-Frequency Variants in EPHA Genes as Markers of Paclitaxel-Induced Peripheral Neuropathy. Clin Cancer Res 2016; 23:1227-1235. [PMID: 27582484 DOI: 10.1158/1078-0432.ccr-16-0694] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/29/2016] [Accepted: 08/16/2016] [Indexed: 11/16/2022]
Abstract
Purpose: Neuropathy is the dose-limiting toxicity of paclitaxel and a major cause for decreased quality of life. Genetic factors have been shown to contribute to paclitaxel neuropathy susceptibility; however, the major causes for interindividual differences remain unexplained. In this study, we identified genetic markers associated with paclitaxel-induced neuropathy through massive sequencing of candidate genes.Experimental Design: We sequenced the coding region of 4 EPHA genes, 5 genes involved in paclitaxel pharmacokinetics, and 30 Charcot-Marie-Tooth genes, in 228 cancer patients with no/low neuropathy or high-grade neuropathy during paclitaxel treatment. An independent validation series included 202 paclitaxel-treated patients. Variation-/gene-based analyses were used to compare variant frequencies among neuropathy groups, and Cox regression models were used to analyze neuropathy along treatment.Results: Gene-based analysis identified EPHA6 as the gene most significantly associated with paclitaxel-induced neuropathy. Low-frequency nonsynonymous variants in EPHA6 were present exclusively in patients with high neuropathy, and all affected the ligand-binding domain of the protein. Accumulated dose analysis in the discovery series showed a significantly higher neuropathy risk for EPHA5/6/8 low-frequency nonsynonymous variant carriers [HR, 14.60; 95% confidence interval (CI), 2.33-91.62; P = 0.0042], and an independent cohort confirmed an increased neuropathy risk (HR, 2.07; 95% CI, 1.14-3.77; P = 0.017). Combining the series gave an estimated 2.5-fold higher risk of neuropathy (95% CI, 1.46-4.31; P = 9.1 × 10-4).Conclusions: This first study sequencing EPHA genes revealed that low-frequency variants in EPHA6, EPHA5, and EPHA8 contribute to the susceptibility to paclitaxel-induced neuropathy. Furthermore, EPHA's neuronal injury repair function suggests that these genes might constitute important neuropathy markers for many neurotoxic drugs. Clin Cancer Res; 23(5); 1227-35. ©2016 AACR.
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Affiliation(s)
- María Apellániz-Ruiz
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Héctor Tejero
- Translational Bioinformatics Unit, Spanish National Cancer Research Centre, Madrid, Spain
| | - Lucía Inglada-Pérez
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,ISCIII Center for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Lara Sánchez-Barroso
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Isabel Calvo
- Medical Oncology Department, Hospital Montepríncipe, Madrid, Spain.,Medical Oncology Department, Centro Integral Oncológico Clara Campal, Madrid, Spain
| | - Beatriz Castelo
- Medical Oncology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Andrés Redondo
- Medical Oncology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Jesús García-Donás
- Gynecological and Genitourinary Tumors Programme, Centro Integral Oncológico Clara Campal, Madrid, Spain
| | - Nuria Romero-Laorden
- Gynecological and Genitourinary Tumors Programme, Centro Integral Oncológico Clara Campal, Madrid, Spain
| | - María Sereno
- Medical Oncology Department, Hospital Universitario Infanta Sofía, Madrid, Spain
| | - María Merino
- Medical Oncology Department, Hospital Universitario Infanta Sofía, Madrid, Spain
| | - María Currás-Freixes
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Cristina Montero-Conde
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Veronika Mancikova
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elisabeth Åvall-Lundqvist
- Department of Oncology and Department of Clinical and Experimental Medicine, Linköpings Universitet, Linköping, Sweden
| | - Henrik Green
- Clinical Pharmacology, Division of Drug Research, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköpings Universitet, Linköping, Sweden.,Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden
| | - Fátima Al-Shahrour
- Translational Bioinformatics Unit, Spanish National Cancer Research Centre, Madrid, Spain
| | - Alberto Cascón
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,ISCIII Center for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Mercedes Robledo
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,ISCIII Center for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Cristina Rodríguez-Antona
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain. .,ISCIII Center for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
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15
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Shibata S, Kawanai T, Hara T, Yamamoto A, Chaya T, Tokuhara Y, Tsuji C, Sakai M, Tachibana T, Inagaki S. ARHGEF10 directs the localization of Rab8 to Rab6-positive executive vesicles. J Cell Sci 2016; 129:3620-3634. [PMID: 27550519 DOI: 10.1242/jcs.186817] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 08/13/2016] [Indexed: 12/18/2022] Open
Abstract
The function of ARHGEF10, a known guanine nucleotide exchange factor (GEF) for RhoA with proposed roles in various diseases, is poorly understood. To understand the precise function of this protein, we raised a monoclonal antibody against ARHGEF10 and determined its localization in HeLa cells. ARHGEF10 was found to localize to vesicles containing Rab6 (of which there are three isoforms, Rab6a, Rab6b and Rab6c), Rab8 (of which there are two isoforms, Rab8a and Rab8b), and/or the secretion marker neuropeptide Y (NPY)-Venus in a Rab6-dependent manner. These vesicles were known to originate from the Golgi and contain secreted or membrane proteins. Ectopic expression of an N-terminal-truncated ARHGEF10 mutant led to the generation of large vesicle-like structures containing both Rab6 and Rab8. Additionally, small interfering (si)RNA-mediated knockdown of ARHGEF10 impaired the localization of Rab8 to these exocytotic vesicles. Furthermore, the invasiveness of MDA-MB231 cells was markedly decreased by knockdown of ARHGEF10, as well as of Rab8. From these results, we propose that ARHGEF10 acts in exocytosis and tumor invasion in a Rab8-dependent manner.
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Affiliation(s)
- Satoshi Shibata
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Tsubasa Kawanai
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Takayuki Hara
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Asuka Yamamoto
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Taro Chaya
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Yasunori Tokuhara
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Chinami Tsuji
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Manabu Sakai
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Taro Tachibana
- Department of Bioengineering, Graduate School of Engineering, Osaka City University, Osaka 558-8585, Japan
| | - Shinobu Inagaki
- Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
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16
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A Novel Analytical Strategy to Identify Fusion Transcripts between Repetitive Elements and Protein Coding-Exons Using RNA-Seq. PLoS One 2016; 11:e0159028. [PMID: 27415830 PMCID: PMC4945064 DOI: 10.1371/journal.pone.0159028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/24/2016] [Indexed: 12/27/2022] Open
Abstract
Repetitive elements (REs) comprise 40-60% of the mammalian genome and have been shown to epigenetically influence the expression of genes through the formation of fusion transcript (FTs). We previously showed that an intracisternal A particle forms an FT with the agouti gene in mice, causing obesity/type 2 diabetes. To determine the frequency of FTs genome-wide, we developed a TopHat-Fusion-based analytical pipeline to identify FTs with high specificity. We applied it to an RNA-seq dataset from the nucleus accumbens (NAc) of mice repeatedly exposed to cocaine. Cocaine was previously shown to increase the expression of certain REs in this brain region. Using this pipeline that can be applied to single- or paired-end reads, we identified 438 genes expressing 813 different FTs in the NAc. Although all types of studied repeats were present in FTs, simple sequence repeats were underrepresented. Most importantly, reverse-transcription and quantitative PCR validated the expression of selected FTs in an independent cohort of animals, which also revealed that some FTs are the prominent isoforms expressed in the NAc by some genes. In other RNA-seq datasets, developmental expression as well as tissue specificity of some FTs differed from their corresponding non-fusion counterparts. Finally, in silico analysis predicted changes in the structure of proteins encoded by some FTs, potentially resulting in gain or loss of function. Collectively, these results indicate the robustness of our pipeline in detecting these new isoforms of genes, which we believe provides a valuable tool to aid in better understanding the broad role of REs in mammalian cellular biology.
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17
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Stankiewicz TR, Linseman DA. Rho family GTPases: key players in neuronal development, neuronal survival, and neurodegeneration. Front Cell Neurosci 2014; 8:314. [PMID: 25339865 PMCID: PMC4187614 DOI: 10.3389/fncel.2014.00314] [Citation(s) in RCA: 281] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/18/2014] [Indexed: 12/11/2022] Open
Abstract
The Rho family of GTPases belongs to the Ras superfamily of low molecular weight (∼21 kDa) guanine nucleotide binding proteins. The most extensively studied members are RhoA, Rac1, and Cdc42. In the last few decades, studies have demonstrated that Rho family GTPases are important regulatory molecules that link surface receptors to the organization of the actin and microtubule cytoskeletons. Indeed, Rho GTPases mediate many diverse critical cellular processes, such as gene transcription, cell–cell adhesion, and cell cycle progression. However, Rho GTPases also play an essential role in regulating neuronal morphology. In particular, Rho GTPases regulate dendritic arborization, spine morphogenesis, growth cone development, and axon guidance. In addition, more recent efforts have underscored an important function for Rho GTPases in regulating neuronal survival and death. Interestingly, Rho GTPases can exert either a pro-survival or pro-death signal in neurons depending upon both the cell type and neurotoxic insult involved. This review summarizes key findings delineating the involvement of Rho GTPases and their effectors in the regulation of neuronal survival and death. Collectively, these results suggest that dysregulation of Rho family GTPases may potentially underscore the etiology of some forms of neurodegenerative disease such as amyotrophic lateral sclerosis.
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Affiliation(s)
- Trisha R Stankiewicz
- Research Service, Veterans Affairs Medical Center Denver, CO, USA ; Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver Denver, CO, USA
| | - Daniel A Linseman
- Research Service, Veterans Affairs Medical Center Denver, CO, USA ; Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver Denver, CO, USA ; Division of Clinical Pharmacology and Toxicology, Department of Medicine and Neuroscience Program, University of Colorado Denver Aurora, CO, USA
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18
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Ekenstedt KJ, Becker D, Minor KM, Shelton GD, Patterson EE, Bley T, Oevermann A, Bilzer T, Leeb T, Drögemüller C, Mickelson JR. An ARHGEF10 deletion is highly associated with a juvenile-onset inherited polyneuropathy in Leonberger and Saint Bernard dogs. PLoS Genet 2014; 10:e1004635. [PMID: 25275565 PMCID: PMC4183422 DOI: 10.1371/journal.pgen.1004635] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 07/18/2014] [Indexed: 11/18/2022] Open
Abstract
An inherited polyneuropathy (PN) observed in Leonberger dogs has clinical similarities to a genetically heterogeneous group of peripheral neuropathies termed Charcot-Marie-Tooth (CMT) disease in humans. The Leonberger disorder is a severe, juvenile-onset, chronic, progressive, and mixed PN, characterized by exercise intolerance, gait abnormalities and muscle atrophy of the pelvic limbs, as well as inspiratory stridor and dyspnea. We mapped a PN locus in Leonbergers to a 250 kb region on canine chromosome 16 (Praw = 1.16×10−10, Pgenome, corrected = 0.006) utilizing a high-density SNP array. Within this interval is the ARHGEF10 gene, a member of the rho family of GTPases known to be involved in neuronal growth and axonal migration, and implicated in human hypomyelination. ARHGEF10 sequencing identified a 10 bp deletion in affected dogs that removes four nucleotides from the 3′-end of exon 17 and six nucleotides from the 5′-end of intron 17 (c.1955_1958+6delCACGGTGAGC). This eliminates the 3′-splice junction of exon 17, creates an alternate splice site immediately downstream in which the processed mRNA contains a frame shift, and generates a premature stop codon predicted to truncate approximately 50% of the protein. Homozygosity for the deletion was highly associated with the severe juvenile-onset PN phenotype in both Leonberger and Saint Bernard dogs. The overall clinical picture of PN in these breeds, and the effects of sex and heterozygosity of the ARHGEF10 deletion, are less clear due to the likely presence of other forms of PN with variable ages of onset and severity of clinical signs. This is the first documented severe polyneuropathy associated with a mutation in ARHGEF10 in any species. Leonberger dogs are a breed originally produced by crossing large-bodied dogs, including Saint Bernards and Newfoundlands. A peripheral neuropathy has been described in Leonbergers that is similar to a group of inherited polyneuropathies known as Charcot-Marie-Tooth disease in humans. We collected a cohort of well-characterized Leonberger polyneuropathy cases and controls, conducted a genome-wide association study, and ultimately identified a highly associated and likely causative mutation in the AHGEF10 gene. This sequence variant is a 10-bp deletion encompassing a splice site, which forces use of a downstream splice site to create a processed mRNA with a premature stop codon, and represents a loss-of-function mutation. The identical mutation was also found in several polyneuropathy-affected Saint Bernards. When homozygous, this deletion results in the onset of clinical signs before four years of age. ARHGEF10 has not previously been associated with severe CMT, but comes from a family of genes shown to be involved in neuron morphology. This first-documented severe polyneuropathy associated with an ARHGEF10 mutation in any species provides an opportunity to gain further insights into the pathobiology of diseases associated with this gene. The ARHGEF10 mutation does not, however, by itself account for all cases of polyneuropathy in Leonbergers or Saint Bernards.
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Affiliation(s)
- Kari J. Ekenstedt
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
| | - Doreen Becker
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Katie M. Minor
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - G. Diane Shelton
- Comparative Neuromuscular Laboratory, Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Edward E. Patterson
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Tim Bley
- Small Animal Clinic, Neruology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Anna Oevermann
- Neurocenter, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Thomas Bilzer
- Institute of Neuropathology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - James R. Mickelson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
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Singh D, Fox SM, Tal-Singer R, Bates S, Riley JH, Celli B. Altered gene expression in blood and sputum in COPD frequent exacerbators in the ECLIPSE cohort. PLoS One 2014; 9:e107381. [PMID: 25265030 PMCID: PMC4179270 DOI: 10.1371/journal.pone.0107381] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 08/14/2014] [Indexed: 11/27/2022] Open
Abstract
Patients with chronic obstructive pulmonary disease (COPD) who are defined as frequent exacerbators suffer with 2 or more exacerbations every year. The molecular mechanisms responsible for this phenotype are poorly understood. We investigated gene expression profile patterns associated with frequent exacerbations in sputum and blood cells in a well-characterised cohort. Samples from subjects from the ECLIPSE COPD cohort were used; sputum and blood samples from 138 subjects were used for microarray gene expression analysis, while blood samples from 438 subjects were used for polymerase chain reaction (PCR) testing. Using microarray, 150 genes were differentially expressed in blood (>±1.5 fold change, p≤0.01) between frequent compared to non-exacerbators. In sputum cells, only 6 genes were differentially expressed. The differentially regulated genes in blood included downregulation of those involved in lymphocyte signalling and upregulation of pro-apoptotic signalling genes. Multivariate analysis of the microarray data followed by confirmatory PCR analysis identified 3 genes that predicted frequent exacerbations; B3GNT, LAF4 and ARHGEF10. The sensitivity and specificity of these 3 genes to predict the frequent exacerbator phenotype was 88% and 33% respectively. There are alterations in systemic immune function associated with frequent exacerbations; down-regulation of lymphocyte function and a shift towards pro-apoptosis mechanisms are apparent in patients with frequent exacerbations.
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Affiliation(s)
- Dave Singh
- University of Manchester, Medicines Evaluation Unit, Manchester, United Kingdom
- * E-mail:
| | - Steven M. Fox
- GlaxoSmithKline, Medicines Research Centre, Stevenage, United Kingdom
| | - Ruth Tal-Singer
- GlaxoSmithKline, King of Prussia, Pennsylvania, United States of America
| | - Stewart Bates
- GlaxoSmithKline, Medicines Research Centre, Stevenage, United Kingdom
| | - John H. Riley
- GlaxoSmithKline, Stockley Park, Uxbridge, United Kingdom
| | - Bartolome Celli
- Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
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Beutler AS, Kulkarni AA, Kanwar R, Klein CJ, Therneau TM, Qin R, Banck MS, Boora GK, Ruddy KJ, Wu Y, Smalley RL, Cunningham JM, Le-Lindqwister NA, Beyerlein P, Schroth GP, Windebank AJ, Züchner S, Loprinzi CL. Sequencing of Charcot-Marie-Tooth disease genes in a toxic polyneuropathy. Ann Neurol 2014; 76:727-37. [PMID: 25164601 DOI: 10.1002/ana.24265] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 08/14/2014] [Accepted: 08/22/2014] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Mutations in Charcot-Marie-Tooth disease (CMT) genes are the cause of rare familial forms of polyneuropathy. Whether allelic variability in CMT genes is also associated with common forms of polyneuropathy-considered "acquired" in medical parlance-is unknown. Chemotherapy-induced peripheral neuropathy (CIPN) occurs commonly in cancer patients and is individually unpredictable. We used CIPN as a clinical model to investigate the association of non-CMT polyneuropathy with CMT genes. METHODS A total of 269 neurologically asymptomatic cancer patients were enrolled in the clinical trial Alliance N08C1 to receive the neurotoxic drug paclitaxel, while undergoing prospective assessments for polyneuropathy. Forty-nine CMT genes were analyzed by targeted massively parallel sequencing of genomic DNA from patient blood. RESULTS A total of 119 (of 269) patients were identified from the 2 ends of the polyneuropathy phenotype distribution: patients that were most and least susceptible to paclitaxel polyneuropathy. The CMT gene PRX was found to be deleteriously mutated in patients who were susceptible to CIPN but not in controls (p = 8 × 10(-3)). Genetic variation in another CMT gene, ARHGEF10, was highly significantly associated with CIPN (p = 5 × 10(-4)). Three nonsynonymous recurrent single nucleotide variants contributed to the ARHGEF10 signal: rs9657362, rs2294039, and rs17683288. Of these, rs9657362 had the strongest effect (odds ratio = 4.8, p = 4 × 10(-4)). INTERPRETATION The results reveal an association of CMT gene allelic variability with susceptibility to CIPN. The findings raise the possibility that other acquired polyneuropathies may also be codetermined by genetic etiological factors, of which some may be related to genes already known to cause the phenotypically related Mendelian disorders of CMT.
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Affiliation(s)
- Andreas S Beutler
- Department of Oncology, Mayo Clinic, Rochester, MN; Cancer Center, Mayo Clinic, Rochester, MN
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21
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Genetic diagnosis of Charcot-Marie-Tooth disease in a population by next-generation sequencing. BIOMED RESEARCH INTERNATIONAL 2014; 2014:210401. [PMID: 25025039 PMCID: PMC4082881 DOI: 10.1155/2014/210401] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/20/2014] [Indexed: 12/14/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is the most prevalent inherited neuropathy. Today more than 40 CMT genes have been identified. Diagnosing heterogeneous diseases by conventional Sanger sequencing is time consuming and expensive. Thus, more efficient and less costly methods are needed in clinical diagnostics. We included a population based sample of 81 CMT families. Gene mutations had previously been identified in 22 families; the remaining 59 families were analysed by next-generation sequencing. Thirty-two CMT genes and 19 genes causing other inherited neuropathies were included in a custom panel. Variants were classified into five pathogenicity classes by genotype-phenotype correlations and bioinformatics tools. Gene mutations, classified certainly or likely pathogenic, were identified in 37 (46%) of the 81 families. Point mutations in known CMT genes were identified in 21 families (26%), whereas four families (5%) had point mutations in other neuropathy genes, ARHGEF10, POLG, SETX, and SOD1. Eleven families (14%) carried the PMP22 duplication and one family carried a MPZ duplication (1%). Most mutations were identified not only in known CMT genes but also in other neuropathy genes, emphasising that genetic analysis should not be restricted to CMT genes only. Next-generation sequencing is a cost-effective tool in diagnosis of CMT improving diagnostic precision and time efficiency.
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DeGeer J, Lamarche-Vane N. Rho GTPases in neurodegeneration diseases. Exp Cell Res 2013; 319:2384-94. [PMID: 23830879 DOI: 10.1016/j.yexcr.2013.06.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022]
Abstract
Rho GTPases are molecular switches that modulate multiple intracellular signaling processes by means of various effector proteins. As a result, Rho GTPase activities are tightly spatiotemporally regulated in order to ensure homeostasis within the cell. Though the roles of Rho GTPases during neural development have been well documented, their participation during neurodegeneration has been far less characterized. Herein we discuss our current knowledge of the role and function of Rho GTPases and regulators during neurodegeneration, and highlight their potential as targets for therapeutic intervention in common neurodegenerative disorders.
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Affiliation(s)
- Jonathan DeGeer
- McGill University, Department of Anatomy and Cell Biology, Montreal, QC, Canada H3A 0C7
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23
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Horn M, Baumann R, Pereira JA, Sidiropoulos PNM, Somandin C, Welzl H, Stendel C, Lühmann T, Wessig C, Toyka KV, Relvas JB, Senderek J, Suter U. Myelin is dependent on the Charcot-Marie-Tooth Type 4H disease culprit protein FRABIN/FGD4 in Schwann cells. Brain 2012; 135:3567-83. [PMID: 23171661 PMCID: PMC3525053 DOI: 10.1093/brain/aws275] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/24/2012] [Accepted: 08/15/2012] [Indexed: 12/21/2022] Open
Abstract
Studying the function and malfunction of genes and proteins associated with inherited forms of peripheral neuropathies has provided multiple clues to our understanding of myelinated nerves in health and disease. Here, we have generated a mouse model for the peripheral neuropathy Charcot-Marie-Tooth disease type 4H by constitutively disrupting the mouse orthologue of the suspected culprit gene FGD4 that encodes the small RhoGTPase Cdc42-guanine nucleotide exchange factor Frabin. Lack of Frabin/Fgd4 causes dysmyelination in mice in early peripheral nerve development, followed by profound myelin abnormalities and demyelination at later stages. At the age of 60 weeks, this was accompanied by electrophysiological deficits. By crossing mice carrying alleles of Frabin/Fgd4 flanked by loxP sequences with animals expressing Cre recombinase in a cell type-specific manner, we show that Schwann cell-autonomous Frabin/Fgd4 function is essential for proper myelination without detectable primary contributions from neurons. Deletion of Frabin/Fgd4 in Schwann cells of fully myelinated nerve fibres revealed that this protein is not only required for correct nerve development but also for accurate myelin maintenance. Moreover, we established that correct activation of Cdc42 is dependent on Frabin/Fgd4 function in healthy peripheral nerves. Genetic disruption of Cdc42 in Schwann cells of adult myelinated nerves resulted in myelin alterations similar to those observed in Frabin/Fgd4-deficient mice, indicating that Cdc42 and the Frabin/Fgd4-Cdc42 axis are critical for myelin homeostasis. In line with known regulatory roles of Cdc42, we found that Frabin/Fgd4 regulates Schwann cell endocytosis, a process that is increasingly recognized as a relevant mechanism in peripheral nerve pathophysiology. Taken together, our results indicate that regulation of Cdc42 by Frabin/Fgd4 in Schwann cells is critical for the structure and function of the peripheral nervous system. In particular, this regulatory link is continuously required in adult fully myelinated nerve fibres. Thus, mechanisms regulated by Frabin/Fgd4-Cdc42 are promising targets that can help to identify additional regulators of myelin development and homeostasis, which may crucially contribute also to malfunctions in different types of peripheral neuropathies.
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Affiliation(s)
- Michael Horn
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Reto Baumann
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Jorge A. Pereira
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Páris N. M. Sidiropoulos
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Christian Somandin
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Hans Welzl
- 2 Division of Neuroanatomy and Behaviour, Institute of Anatomy, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Claudia Stendel
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Tessa Lühmann
- 3 Laboratory for Biologically Oriented Materials, Department of Materials, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Carsten Wessig
- 4 Department of Neurology, University of Würzburg, 97080 Würzburg, Germany
| | - Klaus V. Toyka
- 4 Department of Neurology, University of Würzburg, 97080 Würzburg, Germany
| | - João B. Relvas
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
- 5 Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
| | - Jan Senderek
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ueli Suter
- 1 Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, 8093 Zurich, Switzerland
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