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Thai patients who fulfilled NCCN criteria for breast/ovarian cancer genetic assessment demonstrated high prevalence of germline mutations in cancer susceptibility genes: implication to Asian population testing. Breast Cancer Res Treat 2021; 188:237-248. [PMID: 33649982 PMCID: PMC8233261 DOI: 10.1007/s10549-021-06152-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 02/16/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Germline genetic mutation plays a significant role in breast cancer susceptibility. The strength of such predisposition varies among ethnic groups across the globe, and clinical data from Asian population to develop a strategic approach to who should undergo a genetic test are lacking. METHODS We performed a multigene test with next generation sequencing in Thai patients whose clinical history fulfilled NCCN criteria for breast/ovarian cancer genetic assessment, consists of 306 breast cancer patients, 62 ovarian cancer patients, 14 pancreatic cancer patients and 7 prostate cancer patients. Genetic test result and clinical history were then checked with each NCCN criteria to determined detection rate for each indication. RESULTS There were 83 pathogenic/likely pathogenic (P/LP) variants identified in 104 patients, 44 of these P/LP variants were novel. We reported a high rate of germline P/LP variants in breast cancer (24%), ovarian cancer (37%), pancreatic cancer (14%), and prostate cancer (29%). Germline P/LP variants in BRCA1 and BRCA2 accounted for 80% of P/LP variants found in breast cancer and 57% of P/LP variants found in ovarian cancer. The detection rate of patients who fulfilled NCCN 2019 guideline for genetic/familial high-risk assessment of breast and ovarian cancers was 22-40%. CONCLUSION Overall, the data from this study strongly support the consideration of multigene panel test as a diagnostic tool for patients with inherited cancer susceptibility in Thailand and Asian population. Implementation of the NCCN guideline is applicable, some modification may be needed to be more suitable for Asian population.
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Sargiannidou I, Christophidou-Anastasiadou V, Hadjisavvas A, Tanteles GA, Kleopa KA. Novel GJA1/Cx43 Variant Associated With Oculo-Dento-Digital Dysplasia Syndrome: Clinical Phenotype and Cellular Mechanisms. Front Genet 2021; 11:604806. [PMID: 33584802 PMCID: PMC7873484 DOI: 10.3389/fgene.2020.604806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Oculodentodigital dysplasia syndrome is associated with numerous pathogenic variants in GJA1, the gene encoding connexin43 gap junction protein. A novel in-frame deletion (p.Lys134del) was found in our clinic. The patient showed all the typical dysmorphic features of the syndrome. The functional consequences of this variant were also studied in an in vitro system. Cells expressed significantly less number of gap junction plaques with a great number of them retained intracellularly.
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Affiliation(s)
- Irene Sargiannidou
- Department of Neuroscience, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Violetta Christophidou-Anastasiadou
- Clinical Genetics Center, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Department of Clinical Genetics, Makarios Hospital, Nicosia, Cyprus
| | - Andreas Hadjisavvas
- Department of Molecular Pathology and Electron Microscopy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - George A Tanteles
- Clinical Genetics Center, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Department of Neuroscience, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Center of Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Center for Multiple Sclerosis and Related Disorders, Cyprus School of Molecular Medicine, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:51. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
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Boso F, Taioli F, Cabrini I, Cavallaro T, Fabrizi GM. Aberrant Splicing in GJB1 and the Relevance of 5' UTR in CMTX1 Pathogenesis. Brain Sci 2020; 11:brainsci11010024. [PMID: 33375465 PMCID: PMC7824018 DOI: 10.3390/brainsci11010024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 11/16/2022] Open
Abstract
The second most common form of Charcot-Marie-Tooth disease (CMT) follows an X-linked dominant inheritance pattern (CMTX1), referring to mutations in the gap junction protein beta 1 gene (GJB1) that affect connexin 32 protein (Cx32) and its ability to form gap junctions in the myelin sheath of peripheral nerves. Despite the advances of next-generation sequencing (NGS), attention has only recently also focused on noncoding regions. We describe two unrelated families with a c.-17+1G>T transversion in the 5' untranslated region (UTR) of GJB1 that cosegregates with typical features of CMTX1. As suggested by in silico analysis, the mutation affects the regulatory sequence that controls the proper splicing of the intron in the corresponding mRNA. The retention of the intron is also associated with reduced levels of the transcript and the loss of immunofluorescent staining for Cx32 in the nerve biopsy, thus supporting the hypothesis of mRNA instability as a pathogenic mechanism in these families. Therefore, our report corroborates the role of 5' UTR of GJB1 in the pathogenesis of CMTX1 and emphasizes the need to include this region in routine GJB1 screening, as well as in NGS panels.
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Affiliation(s)
- Federica Boso
- Department of Neurological Sciences, Biomedicine and Movement Sciences, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy; (F.B.); (F.T.); (I.C.)
- Department of Cellular, Computational and Integrative Biology, University of Trento, Via Sommarive 9, 38123 Povo (Trento), Italy
| | - Federica Taioli
- Department of Neurological Sciences, Biomedicine and Movement Sciences, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy; (F.B.); (F.T.); (I.C.)
| | - Ilaria Cabrini
- Department of Neurological Sciences, Biomedicine and Movement Sciences, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy; (F.B.); (F.T.); (I.C.)
| | - Tiziana Cavallaro
- Azienda Ospedaliera Universitaria Integrata Verona—Borgo Roma, Piazzale L.A. Scuro 10, 37134 Verona, Italy;
| | - Gian Maria Fabrizi
- Department of Neurological Sciences, Biomedicine and Movement Sciences, University of Verona, Piazzale L.A. Scuro 10, 37134 Verona, Italy; (F.B.); (F.T.); (I.C.)
- Azienda Ospedaliera Universitaria Integrata Verona—Borgo Roma, Piazzale L.A. Scuro 10, 37134 Verona, Italy;
- Correspondence: ; Tel.: +39-0458124286
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Papaneophytou C, Georgiou E, Kleopa KA. The role of oligodendrocyte gap junctions in neuroinflammation. Channels (Austin) 2020; 13:247-263. [PMID: 31232168 PMCID: PMC6602578 DOI: 10.1080/19336950.2019.1631107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Gap junctions (GJs) provide channels for direct cell-to-cell connectivity serving the homeostasis in several organs of vertebrates including the central (CNS) and peripheral (PNS) nervous systems. GJs are composed of connexins (Cx), which show a highly distinct cellular and subcellular expression pattern. Oligodendrocytes, the myelinating cells of the CNS, are characterized by extensive GJ connectivity with each other as well as with astrocytes. The main oligodendrocyte connexins forming these GJ channels are Cx47 and Cx32. The importance of these channels has been highlighted by the discovery of human diseases caused by mutations in oligodendrocyte connexins, manifesting with leukodystrophy or transient encephalopathy. Experimental models have provided further evidence that oligodendrocyte GJs are essential for CNS myelination and homeostasis, while a strong inflammatory component has been recognized in the absence of oligodendrocyte connexins. Further studies revealed that connexins are also disrupted in multiple sclerosis (MS) brain, and in experimental models of induced inflammatory demyelination. Moreover, induced demyelination was more severe and associated with higher degree of CNS inflammation in models with oligodendrocyte GJ deficiency, suggesting that disrupted connexin expression in oligodendrocytes is not only a consequence but can also drive a pro-inflammatory environment in acquired demyelinating disorders such as MS. In this review, we summarize the current insights from human disorders as well as from genetic and acquired models of demyelination related to oligodendrocyte connexins, with the remaining challenges and perspectives.
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Affiliation(s)
- Christos Papaneophytou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,b Department of Life and Health Sciences, School of Sciences and Engineering , University of Nicosia , Nicosia , Cyprus
| | - Elena Georgiou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus
| | - Kleopas A Kleopa
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,c Neurology Clinics , the Cyprus Institute of Neurology and Genetics, and the Cyprus School of Molecular Medicine , Nicosia , Cyprus
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Transient, Recurrent Central Nervous System Clinical Manifestations of X-Linked Charcot-Marie-Tooth Disease Presenting with Very Long Latency Periods between Episodes: Is Prolonged Sun Exposure a Provoking Factor? Case Rep Neurol Med 2020; 2020:9753139. [PMID: 32685222 PMCID: PMC7336214 DOI: 10.1155/2020/9753139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 06/10/2020] [Accepted: 06/16/2020] [Indexed: 11/17/2022] Open
Abstract
Charcot-Marie-Tooth disease is one of the most common inherited neurological disorders affecting the peripheral nervous system. The common clinical manifestations of the disease are distal muscle weakness and atrophy, often associated with a characteristic steppage gait and foot deformities. Transient acute and recurrent or chronic central nervous system manifestations, predominantly, dysarthria, dysphagia, motor weakness, and ataxia, have been recognized as a feature of the X-linked type 1 of CMT (CMTX1). The CNS symptoms occur typically in young age and often precede the clinical manifestation of the polyneuropathy. Several predisposing factors such as exercise, fever, and returning from areas of high altitude have been described as triggers of the CNS symptoms; however, in many cases, a substantial cause remains undetermined. In this report, we describe a patient with three attacks of transient CNS deficits at the ages of 11, 21, and 38 years, respectively, which were also accompanied by transient white matter abnormalities on MRI. Two of the attacks occurred after prolonged exposure to sunlight. In our knowledge, this is the first documented case with such long latency periods between CNS attacks as well as the only report describing intense sun exposure as a possible provoking factor.
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Kuper WFE, van Alfen C, van Eck L, de Man SA, Willemsen MH, van Gassen KLI, Losekoot M, van Hasselt PM. The c.1A > C start codon mutation in CLN3 is associated with a protracted disease course. JIMD Rep 2020; 52:23-27. [PMID: 32154056 PMCID: PMC7052694 DOI: 10.1002/jmd2.12097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/13/2019] [Accepted: 01/10/2020] [Indexed: 12/12/2022] Open
Abstract
Background CLN3 disease is a disorder of lysosomal homeostasis predominantly affecting the retina and the brain. The severity of the underlying mutations in CLN3 particularly determines onset and course of neurological deterioration. Given the highly conserved start codon code among eukaryotic species, we expected a variant in the start codon of CLN3 to give rise to the classical, that is, severe, phenotype. Case series We present three patients with an identical CLN3 genotype (compound heterozygosity for the common 1 kb deletion in combination with a c.1A > C start codon variant) who all displayed a more attenuated phenotype than expected. While their retinal phenotype was similar to as expected in classical CLN3 disease, their neurological phenotype was delayed. Two patients had an early onset of cognitive impairment, but a particularly slow deterioration afterwards without any obvious motor impairment. The third patient also had a late onset of cognitive impairment. Conclusions Contrasting our initial expectations, patients with a start codon variant in CLN3 may display a protracted phenotype. Future work will have to reveal the exact mechanism behind the assumed residual protein synthesis, and determine whether this may be eligible to start codon targeted therapy.
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Affiliation(s)
- Willemijn F E Kuper
- Department of Metabolic Diseases, Wilhelmina Children's Hospital University Medical Center Utrecht, Utrecht University Utrecht The Netherlands
| | - Claudia van Alfen
- Bartiméus Institute for the Visually Impaired Zeist, Doorn The Netherlands
| | - Linda van Eck
- Bartiméus Institute for the Visually Impaired Zeist, Doorn The Netherlands
| | - Stella A de Man
- Department of Pediatrics Amphia Hospital Breda The Netherlands
| | - Marjolein H Willemsen
- Department of Human Genetics Radboud University Medical Center Nijmegen The Netherlands
| | - Koen L I van Gassen
- Department of Genetics University Medical Center Utrecht Utrecht The Netherlands
| | - Monique Losekoot
- Department of Clinical Genetics Leiden University Medical Center Leiden The Netherlands
| | - Peter M van Hasselt
- Department of Metabolic Diseases, Wilhelmina Children's Hospital University Medical Center Utrecht, Utrecht University Utrecht The Netherlands
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Sargiannidou I, Kagiava A, Kleopa KA. Gene therapy approaches targeting Schwann cells for demyelinating neuropathies. Brain Res 2020; 1728:146572. [PMID: 31790684 DOI: 10.1016/j.brainres.2019.146572] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/12/2019] [Accepted: 11/26/2019] [Indexed: 11/27/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) encompasses numerous genetically heterogeneous inherited neuropathies, which together are one of the commonest neurogenetic disorders. Axonal CMT types result from mutations in neuronally expressed genes, whereas demyelinating CMT forms mostly result from mutations in genes expressed by myelinating Schwann cells. The demyelinating forms are the most common, and may be caused by dominant mutations and gene dosage effects (as in CMT1), as well as by recessive mutations and loss of function mechanisms (as in CMT4). The discovery of causative genes and increasing insights into molecular mechanisms through the study of experimental disease models has provided the basis for the development of gene therapy approaches. For demyelinating CMT, gene silencing or gene replacement strategies need to be targeted to Schwann cells. Progress in gene replacement for two different CMT forms, including CMT1X caused by GJB1 gene mutations, and CMT4C, caused by SH3TC2 gene mutations, has been made through the use of a myelin-specific promoter to restrict expression in Schwann cells, and by lumbar intrathecal delivery of lentiviral viral vectors to achieve more widespread biodistribution in the peripheral nervous system. This review summarizes the molecular-genetic mechanisms of selected demyelinating CMT neuropathies and the progress made so far, as well as the remaining challenges in the path towards a gene therapy to treat these disorders through the use of optimal gene therapy tools including clinically translatable delivery methods and adeno-associated viral (AAV) vectors.
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Affiliation(s)
- Irene Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus; Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
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Diseases of connexins expressed in myelinating glia. Neurosci Lett 2019; 695:91-99. [DOI: 10.1016/j.neulet.2017.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 11/23/2022]
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10
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Koutsis G, Breza M, Velonakis G, Tzartos J, Kasselimis D, Kartanou C, Karavasilis E, Tzanetakos D, Anagnostouli M, Andreadou E, Evangelopoulos ME, Kilidireas C, Potagas C, Panas M, Karadima G. X linked Charcot-Marie-Tooth disease and multiple sclerosis: emerging evidence for an association. J Neurol Neurosurg Psychiatry 2019; 90:187-194. [PMID: 30196252 DOI: 10.1136/jnnp-2018-319014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/31/2018] [Accepted: 08/11/2018] [Indexed: 11/03/2022]
Abstract
OBJECTIVE X linked Charcot-Marie-Tooth disease (CMTX) is a hereditary neuropathy caused by mutations in GJB1 coding for connexin-32, a gap junction protein expressed in Schwann cells, but also found in oligodendrocytes. Four patients with CMTX developing central nervous system (CNS) demyelination compatible with multiple sclerosis (MS) have been individually published. We presently sought to systematically investigate the relationship between CMTX and MS. METHODS Over 20 years, 70 consecutive patients (36 men) with GJB1 mutations were identified at our Neurogenetics Unit, Athens, Greece, and assessed for clinical features suggestive of MS. Additionally, 18 patients with CMTX without CNS symptoms and 18 matched controls underwent brain MRI to investigate incidental findings. Serum from patients with CMTX and MS was tested for CNS immunoreactivity. RESULTS We identified three patients with CMTX who developed clinical features suggestive of inflammatory CNS demyelination fulfilling MS diagnostic criteria. The resulting 20-year MS incidence (4.3%) differed significantly from the highest background 20-year MS incidence ever reported from Greece (p=0.00039). The search for incidental brain MRI findings identified two CMTX cases (11%) with lesions suggestive of focal demyelination compared with 0 control. Moreover, 10 cases in the CMTX cohort had hyperintensity in the splenium of the corpus callosum compared with 0 control (p=0.0002). No specific CNS-reactive humoral factors were identified in patients with CMTX and MS. CONCLUSIONS We have demonstrated a higher than expected frequency of MS in patients with CMTX and identified incidental focal demyelinating lesions on brain MRI in patients with CMTX without CNS symptoms. This provides circumstantial evidence for GJB1 mutations acting as a possible MS risk factor.
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Affiliation(s)
- Georgios Koutsis
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marianthi Breza
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Velonakis
- 2nd Department of Radiology, Medical School, Attikon Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - John Tzartos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Kasselimis
- Neuropsychology and Speech Pathology Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Division of Psychiatry and Behavioral Sciences, School of Medicine, University of Crete, Crete, Greece
| | - Chrisoula Kartanou
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Efstratios Karavasilis
- 2nd Department of Radiology, Medical School, Attikon Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Tzanetakos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Anagnostouli
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisavet Andreadou
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria-Eleftheria Evangelopoulos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Kilidireas
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantin Potagas
- Neuropsychology and Speech Pathology Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marios Panas
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgia Karadima
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
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Papaneophytou CP, Georgiou E, Karaiskos C, Sargiannidou I, Markoullis K, Freidin MM, Abrams CK, Kleopa KA. Regulatory role of oligodendrocyte gap junctions in inflammatory demyelination. Glia 2018; 66:2589-2603. [PMID: 30325069 PMCID: PMC6519212 DOI: 10.1002/glia.23513] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/20/2018] [Accepted: 06/25/2018] [Indexed: 12/27/2022]
Abstract
Gap junctions (GJs) coupling oligodendrocytes to astrocytes and to other oligodendrocytes are formed mainly by connexin47 (Cx47) and a smaller portion by connexin32 (Cx32). Mutations in both connexins cause inherited demyelinating disorders, but their expression is also disrupted in multiple sclerosis (MS). To clarify whether the loss of either Cx47 or Cx32 could modify the outcome of inflammation and myelin loss, we induced experimental autoimmune encephalomyelitis (EAE) in fully backcrossed Cx32 knockout (KO) and Cx47KO mice and compared their outcome with wild type (WT, C57BI/6 N) mice. Cx47KO EAE mice developed the most severe phenotype assessed by clinical scores and behavioral testing, followed by Cx32KO and WT mice. Cx47KO more than Cx32KO EAE mice developed more microglial activation, myelin, and axonal loss than did WT mice. Oligodendrocyte apoptosis and precursor proliferation was also higher in Cx47KO than in Cx32KO or WT EAE mice. Similarly, blood-spinal cord barrier (BSCB) disruption and inflammatory infiltrates of macrophages, T- and B-cells were more severe in Cx47KO than either Cx32KO or WT EAE groups. Finally, expression profiling revealed that several proinflammatory cytokines were higher at the peak of inflammation in the Cx47KO mice and persisted at later stages of EAE in contrast to reduction of their levels in WT EAE mice. Thus, loss of oligodendrocyte GJs aggravates BSCB disruption and inflammatory myelin loss, likely due to dysregulation of proinflammatory cytokines. This mechanism may play an important role in MS brain with reduced connexin expression, as well as in patients with inherited mutations in oligodendrocyte connexins and secondary inflammation.
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MESH Headings
- Animals
- Apoptosis/genetics
- Astrocytes/metabolism
- Astrocytes/pathology
- Blood-Brain Barrier/drug effects
- Blood-Brain Barrier/physiopathology
- Calcium-Binding Proteins/metabolism
- Cell Proliferation/genetics
- Connexins/genetics
- Connexins/metabolism
- Cytokines/metabolism
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Freund's Adjuvant/toxicity
- Gap Junctions/metabolism
- Gap Junctions/pathology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/genetics
- Gene Expression Regulation/physiology
- Hand Strength/physiology
- Macrophages/pathology
- Mice
- Mice, Inbred C57BL
- Microfilament Proteins/metabolism
- Motor Activity/drug effects
- Motor Activity/genetics
- Myelin-Oligodendrocyte Glycoprotein/toxicity
- Oligodendroglia/metabolism
- Oligodendroglia/pathology
- Peptide Fragments/toxicity
- Gap Junction beta-1 Protein
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Affiliation(s)
- Christos P. Papaneophytou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Department of Life and Health Sciences, School of Sciences and EngineeringUniversity of NicosiaNicosiaCyprus
| | - Elena Georgiou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Christos Karaiskos
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Irene Sargiannidou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Kyriaki Markoullis
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Mona M. Freidin
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Charles K. Abrams
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Kleopas A. Kleopa
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
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Biochemical and cellular consequences of the antithrombin p.Met1? mutation identified in a severe thrombophilic family. Oncotarget 2018; 9:33202-33214. [PMID: 30237862 PMCID: PMC6145704 DOI: 10.18632/oncotarget.26059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 07/31/2018] [Indexed: 11/25/2022] Open
Abstract
Nature is always the best inspiration for basic research. A family with severe thrombosis and antithrombin deficiency, the strongest anticoagulant, carried a new mutation affecting the translation-start codon of SERPINC1, the gene encoding antithrombin. Expression of this variant in a eukaryotic cell system produced three different antithrombins. Two downstream methionines were used as alternative initiation codons, generating highly expressed small aglycosylated antithrombins with cytoplasmic localization. Wild-type antithrombin was generated by the use of the mutated AUU as initiation codon. Actually, any codon except for the three stop codons might be used to initiate translation in this strong Kozak context. We show unexpected consequences of natural mutations affecting translation-start codons. Downstream alternative initiation AUG codons may be used when the start codon is mutated, generating smaller molecules with potential different cell localization, biochemical features and unexplored consequences. Additionally, our data further support the use of other codons apart from AUG for initiation of translation in eukaryotes.
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Lapato AS, Tiwari-Woodruff SK. Connexins and pannexins: At the junction of neuro-glial homeostasis & disease. J Neurosci Res 2017; 96:31-44. [PMID: 28580666 DOI: 10.1002/jnr.24088] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/08/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022]
Abstract
In the central nervous system (CNS), connexin (Cx)s and pannexin (Panx)s are an integral component of homeostatic neuronal excitability and synaptic plasticity. Neuronal Cx gap junctions form electrical synapses across biochemically similar GABAergic networks, allowing rapid and extensive inhibition in response to principle neuron excitation. Glial Cx gap junctions link astrocytes and oligodendrocytes in the pan-glial network that is responsible for removing excitotoxic ions and metabolites. In addition, glial gap junctions help constrain excessive excitatory activity in neurons and facilitate astrocyte Ca2+ slow wave propagation. Panxs do not form gap junctions in vivo, but Panx hemichannels participate in autocrine and paracrine gliotransmission, alongside Cx hemichannels. ATP and other gliotransmitters released by Cx and Panx hemichannels maintain physiologic glutamatergic tone by strengthening synapses and mitigating aberrant high frequency bursting. Under pathological depolarizing and inflammatory conditions, gap junctions and hemichannels become dysregulated, resulting in excessive neuronal firing and seizure. In this review, we present known contributions of Cxs and Panxs to physiologic neuronal excitation and explore how the disruption of gap junctions and hemichannels lead to abnormal glutamatergic transmission, purinergic signaling, and seizures.
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Affiliation(s)
- Andrew S Lapato
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, 92521.,Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, CA, 92521
| | - Seema K Tiwari-Woodruff
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, 92521.,Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, CA, 92521.,Neuroscience Graduate Program, University of California Riverside, Riverside, CA, 92521
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14
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Lu YY, Lyu H, Jin SQ, Zuo YH, Liu J, Wang ZX, Zhang W, Yuan Y. Clinical and Genetic Features of Chinese X-linked Charcot-Marie-Tooth Type 1 Disease. Chin Med J (Engl) 2017; 130:1049-1054. [PMID: 28469099 PMCID: PMC5421174 DOI: 10.4103/0366-6999.204925] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND X-linked Charcot-Marie-Tooth type 1 (CMT1X) disease is one of the most common forms of inherited neuropathy caused by mutations in the gap junction beta-1 protein (GJB1) gene (also known as connexin 32). This study presented the clinical and genetic features of a series of Chinese patients with GJB1 gene mutations. METHODS A total of 22 patients from unrelated families, who were referred to Department of Neurology, Peking University First Hospital from January 2005 to January 2016, were identified with GJB1 mutations. Their clinical records and laboratory findings were retrospectively collected and reviewed. Mutations in the GJB1 gene were analyzed by targeted next-generation sequencing (NGS). Nucleotide alternations were confirmed with Sanger sequencing. RESULTS The CMT1X patients predominantly showed distal muscle weakness of lower limbs with mild sensory disturbance. The mean age of onset was 15.6 ± 8.7 years (ranging from 1 year to 42 years). The sudden onset of cerebral symptoms appeared in four patients (18.2%); two were initial symptoms. One case had constant central nervous system (CNS) signs. There were 19 different heterozygous mutations, including 15 known mutations and four novel mutations (c.115G>T, c.380T>A, c.263C>A, and c.818_819insGGGCT). Among the 22 Chinese patients with CMT1X, the frequency of the GJB1 mutation was 4.5% in transmembrane domain 1 (TM1), 4.5% in TM2, 22.7% in TM3, 9.1% in TM4, 4.5% in extracellular 1 (EC1), 27.3% in EC2, 9.1% in intracellular loop, 13.6% in the N-terminal domain, and 4.5% in the C-terminal domain. CMT1X with CNS impairment appeared in five (22.7%) of these patients. CONCLUSIONS This study indicated that CNS impairment was not rare in Chinese CMT1X patients. Mutations in the EC2 domain of the GJB1 gene were hotspot in Chinese CMT1X patients.
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Affiliation(s)
- Yuan-Yuan Lu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - He Lyu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Su-Qin Jin
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yue-Huan Zuo
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Jing Liu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Zhao-Xia Wang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
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15
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Abrams CK, Goman M, Wong S, Scherer SS, Kleopa KA, Peinado A, Freidin MM. Loss of Coupling Distinguishes GJB1 Mutations Associated with CNS Manifestations of CMT1X from Those Without CNS Manifestations. Sci Rep 2017; 7:40166. [PMID: 28071741 PMCID: PMC5223219 DOI: 10.1038/srep40166] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/01/2016] [Indexed: 11/15/2022] Open
Abstract
CMT1X, an X-linked inherited neuropathy, is caused by mutations in GJB1, which codes for Cx32, a gap junction protein expressed by Schwann cells and oligodendrocytes. Many GJB1 mutations cause central nervous system (CNS) abnormality in males, including stable subclinical signs and, less often, short-duration episodes characterized by motor difficulties and altered consciousness. However, some mutations have no apparent CNS effects. What distinguishes mutations with and without CNS manifestations has been unclear. Here we studied a total of 14 Cx32 mutations, 10 of which are associated with florid episodic CNS clinical syndromes in addition to peripheral neuropathy. The other 4 mutations exhibit neuropathy without clinical or subclinical CNS abnormalities. These "PNS-only" mutations (Y151C, V181M, R183C and L239I) form gap junction plaques and produce levels of junctional coupling similar to those for wild-type Cx32. In contrast, mutants with CNS manifestations (F51L, E102del, V139M, R142Q, R142W, R164W T55I, R164Q and C168Y) either form no morphological gap junction plaques or, if they do, produce little or no detectable junctional coupling. Thus, PNS and CNS abnormalities may involve different aspects of connexin function.
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Affiliation(s)
- Charles K. Abrams
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago IL, USA
| | - Mikhail Goman
- Department of Neurology, SUNY Downstate, Brooklyn, NY, USA
| | - Sarah Wong
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Steven S. Scherer
- Department of Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kleopas A. Kleopa
- Neurology Clinics and Neuroscience Laboratory, Cyprus Institute for Neurology and Genetics, Nicosia, Cyprus
| | - Alejandro Peinado
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago IL, USA
| | - Mona M. Freidin
- Department of Neurology and Rehabilitation, College of Medicine, University of Illinois at Chicago, Chicago IL, USA
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Olympiou M, Sargiannidou I, Markoullis K, Karaiskos C, Kagiava A, Kyriakoudi S, Abrams CK, Kleopa KA. Systemic inflammation disrupts oligodendrocyte gap junctions and induces ER stress in a model of CNS manifestations of X-linked Charcot-Marie-Tooth disease. Acta Neuropathol Commun 2016; 4:95. [PMID: 27585976 PMCID: PMC5009701 DOI: 10.1186/s40478-016-0369-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 11/10/2022] Open
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X) is a common form of inherited neuropathy resulting from different mutations affecting the gap junction (GJ) protein connexin32 (Cx32). A subset of CMT1X patients may additionally present with acute fulminant CNS dysfunction, typically triggered by conditions of systemic inflammation and metabolic stress. To clarify the underlying mechanisms of CNS phenotypes in CMT1X we studied a mouse model of systemic inflammation induced by lipopolysaccharide (LPS) injection to compare wild type (WT), connexin32 (Cx32) knockout (KO), and KO T55I mice expressing the T55I Cx32 mutation associated with CNS phenotypes. Following a single intraperitoneal LPS or saline (controls) injection at the age of 40-60 days systemic inflammatory response was documented by elevated TNF-α and IL-6 levels in peripheral blood and mice were evaluated 1 week after injection. Behavioral analysis showed graded impairment of motor performance in LPS treated mice, worse in KO T55I than in Cx32 KO and in Cx32 KO worse than WT. Iba1 immunostaining revealed widespread inflammation in LPS treated mice with diffusely activated microglia throughout the CNS. Immunostaining for the remaining major oligodendrocyte connexin Cx47 and for its astrocytic partner Cx43 revealed widely reduced expression of Cx43 and loss of Cx47 GJs in oligodendrocytes. Real-time PCR and immunoblot analysis indicated primarily a down regulation of Cx43 expression with secondary loss of Cx47 membrane localization. Inflammatory changes and connexin alterations were most severe in the KO T55I group. To examine why the presence of the T55I mutant exacerbates pathology even more than in Cx32 KO mice, we analyzed the expression of ER-stress markers BiP, Fas and CHOP by immunostaining, immunoblot and Real-time PCR. All markers were increased in LPS treated KO T55I mice more than in other genotypes. In conclusion, LPS induced neuroinflammation causes disruption of the main astrocyte-oligodendrocyte GJs, which may contribute to the increased sensitivity of Cx32 KO mice to LPS and of patients with CMT1X to various stressors. Moreover the presence of an intracellularly retained, misfolded CMT1X mutant such as T55I induces ER stress under inflammatory conditions, further exacerbating oligodendrocyte dysfunction and pathological changes in the CNS.
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Affiliation(s)
- Margarita Olympiou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Irene Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kyriaki Markoullis
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Christos Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Styliana Kyriakoudi
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, USA
| | - Kleopas A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 International Airport Avenue, P.O. Box 23462, , 1683, Nicosia, Cyprus.
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