811 results on '"connexin 30"'
Search Results
102. Frequency of GJB2 mutations, GJB6‐D13S1830 and GJB6‐D13S1854 deletions among patients with non‐syndromic hearing loss from the central region of Iran
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Shiva Irani, Hossein Naddafnia, Iman Salahshoorifar, and Zahra Noormohammadi
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0301 basic medicine ,Heterozygote ,lcsh:QH426-470 ,Genotype ,Hearing loss ,autosomal recessive nonsyndromic hearing loss ,Hearing Loss, Sensorineural ,connexin 26 ,030105 genetics & heredity ,Deafness ,Iran ,GJB2 mutation ,Connexins ,03 medical and health sciences ,Gene Frequency ,Polymorphism (computer science) ,Genetics ,medicine ,otorhinolaryngologic diseases ,Humans ,Hearing Loss ,Molecular Biology ,Gene ,Allele frequency ,Genetics (clinical) ,Alleles ,Sequence Deletion ,GJB6 mutation ,biology ,Original Articles ,Penetrance ,connexin 30 ,lcsh:Genetics ,030104 developmental biology ,Mutation ,biology.protein ,Original Article ,medicine.symptom ,Consanguineous Marriage ,GJB6 ,Founder effect - Abstract
Background In the present study, we investigate the prevalence of the GJB2 gene mutations, and deletions in the GJB6 gene, namely del (GJB6‐D13S1830) and del (GJB6‐D13S1854), in patients with autosomal recessive non‐syndromic hearing loss (ARNSHL) from the central region of Iran. Methods One hundred and thirty‐one unrelated ARNSHL cases from the central part of Iran were recruited. Among them, 81% (106 cases) had at least two affected relatives. Coding and noncoding regions of the GJB2 gene were sequenced. Multiplex PCR was used for analysis of del (GJB6‐D13S1830) and del (GJB6‐D13S1854) deletions in GJB6. Results The GJB2 variants were found in 16.79% (22/131) of the patients. The pathogenic variants were 21/131 (16.03%). The nonpathogenic variants were 1/131 (0. 07%). Allele frequency of the c.35delG as the pathogenic variant was the most common with 59.52% (25/42). The remaining pathogenic variants were c.235delC, p.T8M, p.R32H, p.R143Q, p.R143W, c‐23+1G>A. The only nonpathogenic variant was polymorphism p.V27I. Further segregation analysis showed that variant of p.R143Q might have incomplete penetrance. None of the patients had targeted deletions in the GJB6 gene. Conclusion In comparison with reports from other areas of Iran, c.35delG demonstrates the highest frequency within the central region (accounting for 57.14% of cases), probably resulting from the founder effect and consanguineous marriage. The pathology of ARNSHL in such patients could be attributed to defects in Connexin 26 encoded by GJB2.
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- 2019
103. A choreography of intracellular Ca 2+ and extracellular ATP to refine auditory nociceptors before hearing
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Michael G. Leitner and Dominik Oliver
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Calcium Channels, L-Type ,Sensory Receptor Cells ,hair cells ,Action Potentials ,Mice, Transgenic ,Sensory system ,Biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,Mice ,03 medical and health sciences ,Adenosine Triphosphate ,0302 clinical medicine ,purinergic receptors ,Connexin 30 ,otorhinolaryngologic diseases ,Extracellular ,Animals ,News & Views ,Calcium Signaling ,Membrane & Intracellular Transport ,spontaneous activity ,Molecular Biology ,Alert system ,030304 developmental biology ,Mice, Knockout ,Afferent Pathways ,0303 health sciences ,Hearing ability ,General Immunology and Microbiology ,General Neuroscience ,Nociceptors ,pre‐hearing development ,Articles ,calcium waves ,Cochlea ,Choreography ,Hair Cells, Auditory, Outer ,Nociception ,Synapses ,Nociceptor ,Calcium ,sense organs ,Development & Differentiation ,Neuroscience ,Receptors, Purinergic P2X3 ,030217 neurology & neurosurgery ,Intracellular - Abstract
Outer hair cells (OHCs) are highly specialized sensory cells conferring the fine‐tuning and high sensitivity of the mammalian cochlea to acoustic stimuli. Here, by genetically manipulating spontaneous Ca2+ signalling in mice in vivo, through a period of early postnatal development, we find that the refinement of OHC afferent innervation is regulated by complementary spontaneous Ca2+ signals originating in OHCs and non‐sensory cells. OHCs fire spontaneous Ca2+ action potentials during a narrow period of neonatal development. Simultaneously, waves of Ca2+ activity in the non‐sensory cells of the greater epithelial ridge cause, via ATP‐induced activation of P2X3 receptors, the increase and synchronization of the Ca2+ activity in nearby OHCs. This synchronization is required for the refinement of their immature afferent innervation. In the absence of connexin channels, Ca2+ waves are impaired, leading to a reduction in the number of ribbon synapses and afferent fibres on OHCs. We propose that the correct maturation of the afferent connectivity of OHCs requires experience‐independent Ca2+ signals from sensory and non‐sensory cells.
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- 2019
104. Dysfunction of astrocytic connexins 30 and 43 in the medial prefrontal cortex and hippocampus mediates depressive-like behaviours
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Caiyou Hu, Changliu Li, Wenyu Jiang, Wen Zhang, Dongming Huang, and Jiaoqin Qin
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Male ,Hippocampus ,Connexin ,Prefrontal Cortex ,Mice, Transgenic ,Biology ,Amygdala ,Connexins ,03 medical and health sciences ,Behavioral Neuroscience ,Mice ,0302 clinical medicine ,medicine ,Connexin 30 ,Premovement neuronal activity ,Animals ,Prefrontal cortex ,030304 developmental biology ,Neurons ,0303 health sciences ,Depression ,Brain ,Temporal Lobe ,Ventral tegmental area ,Gene expression profiling ,Disease Models, Animal ,medicine.anatomical_structure ,nervous system ,Astrocytes ,Connexin 43 ,sense organs ,Neuroscience ,030217 neurology & neurosurgery ,Astrocyte - Abstract
Astrocytic connexin dysfunction is closely associated with synaptic impairment and contributes to the pathological development of depressive-like behaviours. However, little is known about the expression of connexins in astrocytes from different brain regions, or how tissue specific connexin expression affects local neuronal activity. Here, we established a mouse model of chronic social defeated stress (CSDS), from which we isolated astrocytes from the medial prefrontal cortex (mPFC), hippocampus, amygdala, and ventral tegmental area (VTA). Expression profiling was then performed for connexins Cx26, Cx30, and Cx43. Expression of Cx30 and Cx43 was significantly decreased in mPFC and hippocampus of CSDS mice and was strongly associated with decreases in neuronal activity. Furthermore, overexpression of Cx30 and Cx43 in the mPFC and hippocampus increased neuronal activity and inhibited depressive-like behaviours; while suppression of Cx30 and Cx43 in normal mice was sufficient to reduce neuronal activity and induced depressive-like behaviours. Taken togetner, aberrant expression of astrocytic Cx30 and Cx43 in the mPFC and hippocampus significantly affects brian region-specific neuronal activity and drives depressive-like behaviours. These observations provide novel insights into the role of astrocyte gene expression in stress-induced depressive-like behaviours.
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- 2019
105. Connexin30 and Connexin43 show a time-of-day dependent expression in the mouse suprachiasmatic nucleus and modulate rhythmic locomotor activity in the context of chronodisruption
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Christian Steinhäuser, Anna Stahr, Martin Theis, Charlotte von Gall, Marc Ingenwerth, and Amira A. H. Ali
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Male ,Constant light ,Medizin ,lcsh:Medicine ,Biology ,Biochemistry ,Entrainment ,Glutamatergic ,Mice ,Rhythm ,medicine ,Connexin 30 ,Premovement neuronal activity ,Animals ,Circadian rhythm ,lcsh:QH573-671 ,Molecular Biology ,lcsh:Cytology ,Suprachiasmatic nucleus ,Research ,lcsh:R ,Constant darkness ,Jet lag ,Cell Biology ,Cell biology ,Mice, Inbred C57BL ,cFOS ,SCN ,medicine.anatomical_structure ,nervous system ,Connexin 43 ,Excitatory postsynaptic potential ,Suprachiasmatic Nucleus ,sense organs ,Entrainment (chronobiology) ,Locomotion ,Astrocyte - Abstract
Background The astroglial connexins Cx30 and Cx43 contribute to many important CNS functions including cognitive behaviour, motoric capacity and regulation of the sleep-wake cycle. The sleep wake cycle, is controlled by the circadian system. The central circadian rhythm generator resides in the suprachiasmatic nucleus (SCN). SCN neurons are tightly coupled in order to generate a coherent circadian rhythm. The SCN receives excitatory glutamatergic input from the retina which mediates entrainment of the circadian system to the environmental light-dark cycle. Connexins play an important role in electric coupling of SCN neurons and astrocytic-neuronal signalling that regulates rhythmic SCN neuronal activity. However, little is known about the regulation of Cx30 and Cx43 expression in the SCN, and the role of these connexins in light entrainment of the circadian system and in circadian rhythm generation. Methods We analysed time-of-day dependent as well as circadian expression of Cx30 and Cx43 mRNA and protein in the mouse SCN by means of qPCR and immunohistochemistry. Moreover, we analysed rhythmic spontaneous locomotor activity in mice with a targeted deletion of Cx30 and astrocyte specific deletion of Cx43 (DKO) in different light regimes by means of on-cage infrared detectors. Results Fluctuation of Cx30 protein expression is strongly dependent on the light-dark cycle whereas fluctuation of Cx43 protein expression persisted in constant darkness. DKO mice entrained to the light-dark cycle. However, re-entrainment after a phase delay was slightly impaired in DKO mice. Surprisingly, DKO mice were more resilient to chronodisruption. Conclusion Circadian fluctuation of Cx30 and Cx43 protein expression in the SCN is differently regulated. Cx30 and astroglial Cx43 play a role in rhythm stability and re-entrainment under challenging conditions. Electronic supplementary material The online version of this article (10.1186/s12964-019-0370-2) contains supplementary material, which is available to authorized users.
- Published
- 2019
106. The role of TCPTP on leptin effects on astrocyte morphology
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José Antunes-Rodrigues, Hellen Veida-Silva, Beatriz C. Borges, Maria Célia Jamur, Lucila Leico Kagohara Elias, Lucas Kniess Debarba, and F. M. V. Vechiato
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0301 basic medicine ,Leptin ,Lipopolysaccharides ,medicine.medical_treatment ,Hypothalamus ,Connexin ,030209 endocrinology & metabolism ,ROEDORES ,Protein tyrosine phosphatase ,Biochemistry ,Energy homeostasis ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,medicine ,Connexin 30 ,Animals ,Rats, Wistar ,Molecular Biology ,Cells, Cultured ,Protein Tyrosine Phosphatase, Non-Receptor Type 1 ,Protein Tyrosine Phosphatase, Non-Receptor Type 2 ,Chemistry ,Gap junction ,Organ Size ,medicine.disease ,Cell biology ,Astrogliosis ,Rats ,Up-Regulation ,030104 developmental biology ,medicine.anatomical_structure ,Cytokine ,Animals, Newborn ,Astrocytes ,Connexin 43 ,Cytokines ,hormones, hormone substitutes, and hormone antagonists ,Astrocyte - Abstract
Leptin and LPS has been implicated in the development of hypothalamic astrogliosis in rodents. Astrocytes, which are interconnected by gap junction proteins, have emerged as important players in the control of energy homeostasis exerted by the hypothalamus. To investigate the hypothesis of action of T-cell protein tyrosine phosphatase (TCPTP) on the astrocyte morphology, astrocytes from the hypothalamus of one-day-old rats were stimulated with leptin and LPS (used as a positive control). Leptin and LPS induced a marked increase in astrocyte size, an increase in Ptpn2 (TCPTP gene) and gap junction alpha-1 protein, - Gja1 (connexin 43 - CX43 gene) mRNA expression and a decrease in gap junction protein, alpha 6 - Gja6 (CX30 gene) mRNA expression. Remarkably, these effects on astrocytes morphology and connexins were prevented by Ptpn2 siRNA. Astrocytes are known to produce cytokines; here we show that TCPTP acts as an important regulator of the cytokines and it possesses a reciprocal interplay with protein tyrosine phosphatase 1B (PTP1B). Our findings demonstrate that leptin and LPS alter astrocyte morphology by increasing TCPTP, which in turn modulates connexin 30 (CX30) and connexin 43 (CX43) expression. TCPTP and PTP1B seem to act in the regulation of cytokine production in astrocytes.
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- 2019
107. Structural determinants underlying permeant discrimination of the Cx43 hemichannel
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Francesco Zonta, Morten Schak Nielsen, Thomas Litman, Brian Skriver Nielsen, Nanna MacAulay, and Thomas Farkas
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0301 basic medicine ,connexin ,Protein Conformation ,Xenopus ,Connexin ,connexon (hemichannel) ,Molecular Dynamics Simulation ,Biochemistry ,Permeability ,Connexon ,Substrate Specificity ,Divalent ,connexin 43 ,gap junction ,03 medical and health sciences ,biophysics ,Extracellular ,Protein Isoforms ,Amino Acid Sequence ,Molecular Biology ,computer modeling ,chemistry.chemical_classification ,030102 biochemistry & molecular biology ,biology ,membrane channel ,Chemistry ,Cell Membrane ,Gap junction ,Conductance ,Cell Biology ,biology.organism_classification ,connexin 30 ,Electrophysiological Phenomena ,030104 developmental biology ,Connexin 43 ,Biophysics ,Membrane channel ,sense organs ,ion conductivity ,permeability ,pharmacology ,Porosity ,Molecular Biophysics - Abstract
Connexin (Cx) gap junction channels comprise two hemichannels in neighboring cells, and their permeability is well-described, but permeabilities of the single Cx hemichannel remain largely unresolved. Moreover, determination of isoform-specific Cx hemichannel permeability is challenging because of concurrent expression of other channels with similar permeability profiles and inhibitor sensitivities. The mammalian Cx hemichannels Cx30 and Cx43 are gated by extracellular divalent cations, removal of which promotes fluorescent dye uptake in both channels but atomic ion conductance only through Cx30. To determine the molecular determinants of this difference, here we employed chimeras and mutagenesis of predicted pore-lining residues in Cx43. We expressed the mutated channels in Xenopus laevis oocytes to avoid background activity of alternative channels. Oocytes expressing a Cx43 hemichannel chimera containing the N terminus or the first extracellular loop from Cx30 displayed ethidium uptake and, unlike WT Cx43, ion conduction, an observation further supported by molecular dynamics simulations. Additional C-terminal truncation of the chimeric Cx43 hemichannel elicited an even greater ion conductance with a magnitude closer to that of Cx30. The inhibitory profile for the connexin hemichannels depended on the permeant, with conventional connexin hemichannel inhibitors having a higher potency toward the ion conductance pathway than toward fluorescent dye uptake. Our results demonstrate a permeant-dependent, isoform-specific inhibition of connexin hemichannels. They further reveal that the outer segments of the pore-lining region, including the N terminus and the first extracellular loop, together with the C terminus preclude ion conductance of the open Cx43 hemichannel.
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- 2019
108. Etiologia das perdas auditivas congênita e adquirida no período neonatal
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Faistauer, Marina, Costa, Sady Selaimen da, and Rosito, Leticia Petersen Schmidt
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Connexin 26 ,Congenital ,Etiology ,Etiologia ,Connexin 30 ,Estudos de coortes ,Prevalência ,Criança ,Doenças e anormalidades congênitas, hereditárias e neonatais ,Hearing loss ,Perda auditiva ,Neonatal screening ,Triagem neonatal - Abstract
INTRODUÇÃO: A perda auditiva é prejudicial à comunicação e interfere na qualidade de vida das pessoas afetadas. Iniciativas que contribuam para o seu diagnóstico precoce, assim como para intervenções mais adequadas e para melhores prognósticos para os deficientes auditivos são de grande importância. O diagnóstico etiológico e a avaliação das consequências da implementação da triagem auditiva neonatal (TAN) são algumas dessas iniciativas. OBJETIVOS: 1. Identificar as etiologias da perda auditiva e suas prevalências; 2. Avaliar o impacto TAN na idade do diagnóstico e no início do tratamento da perda auditiva dos pacientes de um ambulatório referência em surdez infantil do sul do Brasil. DELINEAMENTO: Estudo de prevalência e de coorte. MÉTODO: Para o estudo de prevalência das etiologias foram avaliadas 140 crianças de zero a 12 anos com perdas auditivas sensorioneural ou mista, bilateral, congênita ou adquirida no período neonatal. Foi realizada anamnese dirigida, exame físico, exames audiológicos e eletrofisiológicos, além de exames de imagem e genéticos (sequenciamento do gene GJB2 e pesquisa da del(GJB6-D13S1830) do gene GJB6). Para o estudo de coorte, foram avaliadas 135 crianças da mesma amostra, tendo sido excluídas as com perda auditiva progressiva após o diagnóstico. Foram separadas em dois grupos: as que realizaram TAN e as que não realizaram. Os grupos foram comparados quanto às idades no início da avaliação em centro especializado, no início da intervenção e no primeiro implante coclear. RESULTADOS: Quanto às etiologias, foi encontrada a seguinte prevalência: (a) adquirida no período neonatal em 22,1% dos casos; (b) infecção congênita em 6,4%; (c) genética em 22,1%; (d) neuropatia auditiva em 10%; (e) indeterminada em 31,4%; e (f) outra em 7,9%. Foram identificados dez casos homozigotos e sete heterozigotos da mutação 35delG, além de duas variantes raras de GJB2: p.Try172* e p.Arg184Pro. Foi encontrado um caso com homozigose de del(GJB6-D13S1830). Na coorte, a mediana (percentil 25 e 75) da idade na primeira consulta em centro especializado, no início do tratamento e no primeiro implante coclear foram 1,42 (0,50 e 2,50) anos, 2,00 (1,00 e 3,52) anos e 2,83 (1,83 e 4,66) anos, respectivamente. As crianças que realizaram a TAN apresentaram idades inferiores às das que não realizaram nos três momentos avaliados (pA (p.Try172*). As crianças que fizeram os testes da TAN chegaram à primeira consulta em centro especializado e iniciaram o tratamento com idade inferior às que não fizeram. No entanto, as crianças que passaram na triagem e apresentaram posteriormente perda auditiva sofreram atraso no diagnóstico e na intervenção. INTRODUCTION: Hearing loss is detrimental to communication and interferes in the patient’s life quality. Measures that contribute to its early diagnosis, adequate intervention and better prognosis for people with hearing loss are of great importance. Among them are the etiological diagnosis and the evaluation of the implementation consequences of the newborn hearing screening program (NHSP). PURPOSE: Identify the etiologies of hearing loss and its prevalence; 2. Evaluate the NHSP impact in the age of diagnosis and the beginning of treatment of hearing loss of patients from a reference clinic of childhood deafness in southern Brazil. STUDY DESIGN: Cross-sectional and cohort studies. METHODS: For the cross-sectional study of the etiologies, we evaluated 140 children from 0 to 12 years of age with sensorineural or mixed hearing loss, bilateral, congenital or acquired in neonatal period. We assembled medical history, physical examination, audiological and electrophysiological tests, as well as imaging exams and genetic tests (sequencing of GJB2 gene and del(GJB6-D13S1830) of GJB6). For the cohort study, 135 children from the same sample were evaluated (except those with progressive hearing loss after diagnosis). They were divided in two groups: those who took the NHSP and those who did not. The groups were compared regarding the age at the beginning of the evaluation in a specialized center, as well as at the beginning of the intervention and the first cochlear implant. RESULTS: The etiologies of the hearing losses were: a) acquired in neonatal period in 22.1% of the cases, b) congenital infection in 6.4%, c) genetic in 22.1%, d) auditory neuropathy in 10%, e) undetermined in 31.4% and f) other in 7.9%. We identified ten homozygous cases and seven heterozygous of the 35delG mutation, as well as two rare variants of GJB2: p.Try172* and p.Arg184Pro. We found one case of del(GJB6-D13S1830), homozygous. In the cohort, the median (percentile 25 and 75) of the age in the first consultation in a specialized center, in the beginning of the treatment and in the first cochlear implant was of 1.42 (0.50 e 2.50) years, 2.00 (1.00 e 3.52) years and 2.83 (1.83 e 4.66) years, respectively. The children that took the NHSP presented younger age if compared to those who did not take it in the three moments of evaluation (pA (p.Try172*). The children who took the tests of the NHSP arrived in the first consultation in a specialized center and started the treatment at a younger age if compared to those who did not take it. However, those who passed the NHSP and presented hearing loss later, had delayed diagnosis and intervention.
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- 2019
109. Anisotropic Panglial Coupling Reflects Tonotopic Organization in the Inferior Colliculus
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Vanessa Augustin, Christian Steinhäuser, Dennis J. Weingarten, Simon L. Wadle, Jonathan Stephan, Camille Philippot, Julia Langer, Ronald Jabs, and Christine R. Rose
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0301 basic medicine ,Inferior colliculus ,oligodendrocytes ,connexin 43 ,lcsh:RC321-571 ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,medicine ,auditory brainstem ,Anisotropy ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,gap junctions ,Original Research ,Chemistry ,IC ,Gap junction ,astrocytes ,connexin 30 ,Coupling (electronics) ,030104 developmental biology ,medicine.anatomical_structure ,Brainstem ,Tonotopy ,Neuroscience ,Nucleus ,030217 neurology & neurosurgery ,Astrocyte - Abstract
Astrocytes and oligodendrocytes in different brain regions form panglial networks and the topography of such networks can correlate with neuronal topography and function. Astrocyte-oligodendrocyte networks in the lateral superior olive (LSO)—an auditory brainstem nucleus—were found to be anisotropic with a preferred orientation orthogonally to the tonotopic axis. We hypothesized that such a specialization might be present in other tonotopically organized brainstem nuclei, too. Thus, we analyzed gap junctional coupling in the center of the inferior colliculus (IC)—another nucleus of the auditory brainstem that exhibits tonotopic organization. In acute brainstem slices obtained from mice, IC networks were traced employing whole-cell patch-clamp recordings of single sulforhodamine (SR) 101-identified astrocytes and concomitant intracellular loading of the gap junction-permeable tracer neurobiotin. The majority of dye-coupled networks exhibited an oval topography, which was preferentially oriented orthogonal to the tonotopic axis. Astrocyte processes showed preferentially the same orientation indicating a correlation between astrocyte and network topography. In addition to SR101-positive astrocytes, IC networks contained oligodendrocytes. Using Na+ imaging, we analyzed the capability of IC networks to redistribute small ions. Na+ bi-directionally diffused between SR101-positive astrocytes and SR101-negative cells—presumably oligodendrocytes—showing the functionality of IC networks. Taken together, our results demonstrate that IC astrocytes and IC oligodendrocytes form functional anisotropic panglial networks that are preferentially oriented orthogonal to the tonotopic axis. Thus, our data indicate that the topographic specialization of glial networks seen in IC and LSO might be a general feature of tonotopically organized auditory brainstem nuclei.
- Published
- 2018
110. Connexin 30 Deficiency Attenuates Chronic but Not Acute Phases of Experimental Autoimmune Encephalomyelitis Through Induction of Neuroprotective Microglia
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Mei Fang, Ryo Yamasaki, Guangrui Li, Katsuhisa Masaki, Hiroo Yamaguchi, Atsushi Fujita, Noriko Isobe, and Jun-ichi Kira
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0301 basic medicine ,lcsh:Immunologic diseases. Allergy ,connexin ,Encephalomyelitis, Autoimmune, Experimental ,Central nervous system ,Immunology ,experimental autoimmune encephalomyelitis ,microglia ,multiple sclerosis ,Neuroprotection ,Myelin oligodendrocyte glycoprotein ,03 medical and health sciences ,Mice ,0302 clinical medicine ,astrocyte ,medicine ,Connexin 30 ,Immunology and Allergy ,Animals ,Humans ,chronic neuroinflammation ,Neuroinflammation ,Original Research ,Mice, Knockout ,Microglia ,biology ,Arginase ,business.industry ,Multiple sclerosis ,Brain-Derived Neurotrophic Factor ,Experimental autoimmune encephalomyelitis ,medicine.disease ,Peptide Fragments ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Connexin 43 ,Acute Disease ,Chronic Disease ,biology.protein ,Female ,Myelin-Oligodendrocyte Glycoprotein ,business ,lcsh:RC581-607 ,030217 neurology & neurosurgery ,Astrocyte - Abstract
Glial connexins (Cxs) form gap junction channels through which a pan-glial network plays key roles in maintaining homeostasis of the central nervous system (CNS). In multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), expression of astrocytic Cx43 is lost in acute lesions but upregulated in chronic plaques, while astrocytic Cx30 is very low in normal white matter and changes in its expression have not been convincingly shown. In Cx30 or Cx43 single knockout (KO) mice and even in Cx30/Cx43 double KO mice, acute EAE is unaltered. However, the effects of Cx30/Cx43 deficiency on chronic EAE remains to be elucidated. We aimed to clarify the roles of Cx30 in chronic neuroinflammation by studying EAE induced by myelin oligodendrocyte glycoprotein peptide 35-55 in Cx30 KO mice. We found that Cx30 deficiency improved the clinical symptoms and demyelination of chronic but not acute EAE without influencing CD3+ T cell infiltration. Furthermore, increased ramified microglia in the naive state and induced earlier and stronger microglial activation in the acute and chronic phases of EAE was observed. These activated microglia had an anti-inflammatory phenotype, as shown by the upregulation of arginase-1 and brain-derived neurotrophic factor and the downregulation of nitric oxide synthase 2. In the naive state, Cx30 deficiency induced modest enlargement of astrocytic processes in the spinal cord gray matter and a partial reduction of Cx43 expression in the spinal cord white matter. These astrocytes in Cx30 KO mice showed earlier and stronger activation during the acute phase of EAE, with upregulated A2 astrocyte markers and a significant decrease in Cx43 in the chronic phases. Spinal cord neurons and axons were more preserved in Cx30 KO mice than in littermates in the chronic phase of EAE. These findings suggest that Cx30 deficiency increased ramified microglia in the CNS in the naive state and improved chronic EAE through redirecting microglia toward an anti-inflammatory phenotype, suggesting a hitherto unknown critical role of astrocytic Cx30 in regulating microglial number and functional state.
- Published
- 2018
111. Tricellular adherens junctions provide a cell surface delivery platform for connexin 26/30 oligomers in the cochlea
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Jean Defourny and Marc Thiry
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0301 basic medicine ,Connexin ,Proximity ligation assay ,Connexins ,Adherens junction ,03 medical and health sciences ,0302 clinical medicine ,Connexin 30 ,otorhinolaryngologic diseases ,Humans ,Lipid raft ,Cochlea ,biology ,Chemistry ,Cadherin ,Gap junction ,Gap Junctions ,Adherens Junctions ,Sensory Systems ,Cell biology ,Connexin 26 ,030104 developmental biology ,biology.protein ,Membrane channel ,030217 neurology & neurosurgery ,GJB6 - Abstract
In the cochlea, connexins 26 (Cx26) and 30 (Cx30) largely co-assemble into heteromeric gap junctions, which connect adjacent non-sensory epithelial cells. These channels are believed to ensure the rapid removal of K+ away from the base of sensory hair cells, resulting in K+ recycling back to the endolymph to maintain cochlear homeostasis. Many of the mutations in GJB2 and GJB6, which encode CX26 and CX30, impair the formation of membrane channels and cause autosomal hearing loss in humans. Although recent advances have been made, several important questions remain about connexin trafficking and gap junction biogenesis. Here we show that tricellular adherens junctions present at the crossroad between adjacent gap junction plaques, provide an unexpected cell surface delivery platform for Cx26/Cx30 oligomers. Using an in situ proximity ligation assay, we detected the presence of non-junctional Cx26/Cx30 oligomers within lipid raft-enriched tricellular junction sites. In addition, we observed that cadherin homophilic interactions are critically involved in microtubule-mediated trafficking of Cx26/Cx30 oligomers to the cell surface. Overall, our results unveil an unexpected role for tricellular junctions in the trafficking and assembly of membrane channels.
- Published
- 2021
112. Differential expression of astrocytic connexins in a mouse model of prenatal alcohol exposure
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Michael O. Poulter, James D. Brien, Lihua Wang, Shanthini Mylvaganam, Georg Zoidl, Michal Krawczyk, Bhushan Kapur, Christiane Zoidl, Meera Ramani, James N. Reynolds, and Peter L. Carlen
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Male ,0301 basic medicine ,medicine.medical_specialty ,animal structures ,Offspring ,Connexin ,Hippocampus ,Hyperexcitability ,Biology ,Connexins ,lcsh:RC321-571 ,03 medical and health sciences ,0302 clinical medicine ,Pregnancy ,Internal medicine ,Connexin 30 ,medicine ,Animals ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Cerebral Cortex ,Neurons ,Fetus ,FASD ,Gap junction ,Gap Junctions ,Pannexin ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,Neurology ,Cerebral cortex ,Alcohols ,Astrocytes ,Connexin 43 ,Prenatal Exposure Delayed Effects ,Excitatory postsynaptic potential ,Astrocytic connexins ,Female ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Maternal alcohol consumption during gestation can cause serious injury to the fetus, and may result in a range of physiological and behavioral impairments, including increased seizure susceptibility, that are collectively termed fetal alcohol spectrum disorder (FASD). The cellular mechanisms underlying increased seizure susceptibility in FASD are not well understood, but could involve altered excitatory coupling of neuronal populations mediated by gap junction proteins. We utilized a mouse model of the prenatal alcohol exposure (PAE) to study the expression pattern of connexin (Cx) major components of gap junctions, and pannexin proteins, which form membrane channels, in the brain of 2–3 weeks old PAE and control postnatal offspring. PAE during the first trimester-equivalent period of pregnancy in mice resulted in significant up-regulation of Cx30 mRNA and Cx30 total protein in the hippocampus of PAE animals compared to age-matched controls. Surface level expression of both dimeric and monomeric Cx30 were also found to be significantly up-regulated in both hippocampus and cerebral cortex of PAE animals compared to age-matched controls. On the membrane surface, the fast migrating form of Cx43 was found to be up-regulated in the hippocampus of PAE mice. However, we did not see any up-regulation of the phosphorylated forms of Cx43 on the membrane surface. These results indicate that the expression and processing of astrocytic connexins (Cx30, Cx43) are up-regulated in the brain of PAE offspring, and these changes could play a role in the cerebral hyperexcitability observed in these animals.
- Published
- 2016
113. Connexin 30 deficiency attenuates A2 astrocyte responses and induces severe neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride Parkinson’s disease animal model
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Fujita, Atsushi, Yamaguchi, Hiroo, Yamasaki, Ryo, Cui, Yiwen, Matsuoka, Yuta, Yamada, Ken-ichi, and Kira, Jun-ichi
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- 2018
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114. Spectrum and frequency of GJB2, GJB6 and SLC26A4 gene mutations among nonsyndromic hearing loss patients in eastern part of India
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Silpita Paul, Bidisha Adhikary, Biswabandhu Bankura, Biswanath Maity, Arup Kumar Pattanayak, Madhusudan Das, Sudakshina Ghosh, and Subhradev Biswas
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Male ,Biallelic Mutation ,Hearing loss ,DNA Mutational Analysis ,India ,Deafness ,Biology ,medicine.disease_cause ,Connexins ,Gene Frequency ,Connexin 30 ,Prevalence ,otorhinolaryngologic diseases ,Genetics ,medicine ,Humans ,Genetic Predisposition to Disease ,Allele ,Gene ,Allele frequency ,Genetic Association Studies ,Mutation ,Base Sequence ,Membrane Transport Proteins ,General Medicine ,medicine.disease ,Connexin 26 ,Sulfate Transporters ,Case-Control Studies ,biology.protein ,Female ,sense organs ,medicine.symptom ,GJB6 ,Enlarged vestibular aqueduct - Abstract
Genetically caused nonsyndromic hearing loss is highly heterogeneous. Inspite of this large heterogeneity, mutations in the genes GJB2, GJB6 and SLC26A4 are major contributors. The mutation spectrum of these genes varies among different ethnic groups. Only a handful of studies focused on the altered genetic signature of these genes in different demographic regions of India but never focused on the eastern part of the country. Our study for the first time aimed to characterize the mutation profile of these genes in hearing loss patients of West Bengal state, India. Mutations in GJB2, GJB6 and SLC26A4 genes were screened by bidirectional sequencing from 215 congenital nonsyndromic hearing loss patients. Radiological diagnosis was performed in patients with SLC26A4 mutations by temporal bone CT scan. The study revealed that 4.65% and 6.97% patients had monoallelic and biallelic GJB2 mutations respectively. Six mutations were identified, p.W24X being the most frequent one accounting for 71.05% of the mutated alleles. Mutations in GJB6 including the previously identified deletion mutation (GJB6-D13S1830) were not identified in our study. Further, no patients harbored biallelic mutations in the SLC26A4 gene or the common inner ear malformation Enlarged Vestibular Aqueduct (EVA). The mutation profile of GJB2 in our study is distinct from other parts of India, suggesting that the mutation spectrum of this gene varies with ethnicity and geographical origin. The absence of GJB6 mutations and low frequency of SLC26A4 mutations suggest that additional genetic factors may also contribute to this disease.
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- 2015
115. Calcium signaling in the cochlea – Molecular mechanisms and physiopathological implications
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Ceriani Federico and Mammano Fabio
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Hearing ,Inner ear ,Transducer adaptation ,Ca2+ channels ,Cadherin 23 ,Protocadherin 15 ,Plasma-membrane Ca2+-ATPase ,Prestin ,Intracellular stores ,Calcium release ,Mitochondria ,Ribbon synapse ,Adenosine-5'-triphosphate ,Inositol 1,4,5-trisphosphate ,Connexin 26 ,Connexin 30 ,Deafness ,Mouse models ,Medicine ,Cytology ,QH573-671 - Abstract
Abstract Calcium ions (Ca2+) regulate numerous and diverse aspects of cochlear and vestibular physiology. This review focuses on the Ca2+ control of mechanotransduction and synaptic transmission in sensory hair cells, as well as on Ca2+ signalling in non-sensory cells of the developing cochlea.
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- 2012
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116. Connexin 30 deficiency attenuates A2 astrocyte responses and induces severe neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride Parkinson’s disease animal model
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Yuta Matsuoka, Yiwen Cui, Ryo Yamasaki, Atsushi Fujita, Ken Ichi Yamada, Hiroo Yamaguchi, and Jun Ichi Kira
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0301 basic medicine ,Male ,Striatum ,lcsh:RC346-429 ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Glial cell line-derived neurotrophic factor ,Annexin A2 ,Oligonucleotide Array Sequence Analysis ,Dopaminergic neuron ,Glial fibrillary acidic protein ,biology ,Chemistry ,General Neuroscience ,MPTP ,Neurodegeneration ,Microfilament Proteins ,S100 Proteins ,Astrogliosis ,medicine.anatomical_structure ,Neurology ,1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine ,Astrocyte ,medicine.medical_specialty ,Tyrosine 3-Monooxygenase ,Immunology ,Neurotoxins ,Mice, Transgenic ,Striatonigral Degeneration ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Internal medicine ,Glial Fibrillary Acidic Protein ,medicine ,Connexin 30 ,Animals ,Glial Cell Line-Derived Neurotrophic Factor ,lcsh:Neurology. Diseases of the nervous system ,Dopamine Plasma Membrane Transport Proteins ,Tyrosine hydroxylase ,Research ,Gene Expression Profiling ,Calcium-Binding Proteins ,MPTP Poisoning ,medicine.disease ,Disease Models, Animal ,030104 developmental biology ,Endocrinology ,nervous system ,Gene Expression Regulation ,Astrocytes ,Connexin 43 ,biology.protein ,Parkinson’s disease ,030217 neurology & neurosurgery - Abstract
Background The first pathology observed in Parkinson’s disease (PD) is ‘dying back’ of striatal dopaminergic (DA) terminals. Connexin (Cx)30, an astrocytic gap junction protein, is upregulated in the striatum in PD, but its roles in neurodegeneration remain elusive. We investigated Cx30 function in an acute PD model by administering 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to wild-type (WT) and Cx30 knockout (KO) mice. Methods On days 1 and 7 after MPTP administration, we evaluated changes in astrocytic Cx30, Cx43, glial fibrillary acidic protein, and ionised calcium-binding adapter molecule 1 expression by immunostaining and biochemical analysis. Loss of DA neurons was evaluated by tyrosine hydroxylase immunostaining. Gene expression was analysed using A1, A2, pan-reactive astrocyte microarray gene sets, and M1, M2, and M1/M2 mixed microglial microarray gene sets. Real-time PCR and in situ hybridisation were performed to evaluate glial cell-derived neurotrophic factor (Gdnf) and S100a10 expression. Striatal GDNF protein levels were determined by enzyme-linked immunosorbent assay. Results MPTP treatment induced upregulation of Cx30 and Cx43 levels in the striatum of WT and KO mice. DA neuron loss was accelerated in Cx30 KO compared with WT mice after MPTP administration, despite no change in the striatal concentration of methyl-4-phenylpyridinium+. Astrogliosis in the striatum of Cx30 KO mice was attenuated by MPTP, whereas microglial activation was unaffected. Microarrays of the striatum showed reduced expression of pan-reactive and A2 astrocyte genes after MPTP treatment in Cx30 KO compared with WT mice, while M1, M2, and M1/M2 mixed microglial gene expression did not change. MPTP reduced the number of striatal astrocytes co-expressing Gdnf mRNA and S100β protein or S100a10 mRNA and S100β protein and also reduced the level of GDNF in the striatum of Cx30 KO compared with WT mice. Conclusions These findings indicate that Cx30 plays critical roles in astrocyte neuroprotection in an MPTP PD model. Electronic supplementary material The online version of this article (10.1186/s12974-018-1251-0) contains supplementary material, which is available to authorized users.
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- 2018
117. GJB3/GJB6 screening in GJB2 carriers with idiopathic hearing loss: Is it necessary?
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Chen, Kaitian, Wu, Xuan, Zong, Ling, and Jiang, Hongyan
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Family Health ,Male ,Models, Molecular ,Heterozygote ,Adolescent ,Connexins ,Cohort Studies ,Connexin 26 ,Young Adult ,Child, Preschool ,Mutation ,otorhinolaryngologic diseases ,Connexin 30 ,Humans ,Computer Simulation ,Female ,Genetic Testing ,Child ,Hearing Loss ,Research Articles - Abstract
BACKGROUND: Genetic analysis detected excessive mono‐allelic recessive GJB2 mutations in individuals with idiopathic deafness; the remaining alleles in trans/cis are underdetermined. The aim of this study was to assess the contributions of variants in GJB3 or GJB6 to non‐syndromic sensorineural hearing impairment (NSHI) in Chinese patients with mono‐allelic GJB2 mutations. METHODS: The entire coding sequences of GJB3/GJB6, as well as deletions in GJB6, in a cohort of NSHI patients (n = 100) carrying likely pathogenic heterozygous GJB2 mutations, were tested. Targeted next generation sequencing was further performed in a multiplex family GDHY with moderate to profound NSHI. RESULTS: Putatively causative GJB3 variant underlied 1% (1/100) in this cohort. In family GDHY, we identified a rare GJB3 c.250G>A mutation, as double heterozygotes with GJB2 c.109G>A and/or a novel GJB2 mutation c.638T>C predicted to be damaging in a digenic inheritance after precluding other attributable mutations from 127 deafness genes. No GJB6 mutation was found. CONCLUSIONS: GJB3/GJB6 variants account for a low proportion in autosomal recessive GJB2 mutation carriers in our cohort. Environmental causes, or other NSHI relevant genes, revealed by targeted next generation sequencing or whole exome sequencing, may play major roles in triggering deafness in these patients.
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- 2018
118. Connexin 30 controls astroglial polarization during postnatal brain development
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Alexis-Pierre Bemelmans, Grégory Ghézali, Laure-Elise Pillet, Ulrike Pannasch, Flora Llense, Nathalie Rouach, Sandrine Etienne Manneville, Charles-Félix Calvo, Pascal Ezan, Sorbonne Université - Faculté de Médecine (SU FM), Sorbonne Université (SU), Centre interdisciplinaire de recherche en biologie (CIRB), Collège de France (CdF)-Institut National de la Santé et de la Recherche Médicale (INSERM)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris Descartes - Paris 5 (UPD5), Polarité cellulaire, Migration et Cancer / Cell Polarity, Migration and Cancer, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Maladies Neurodégénératives - UMR 9199 (LMN), Université Paris-Sud - Paris 11 (UP11)-Service MIRCEN (MIRCEN), Institut de Biologie François JACOB (JACOB), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Biologie François JACOB (JACOB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), This work was supported by grants from the European Research Council (consolidator grant 683154 to N.R.), from the Paris 6 University doctoral school ED3C and Labex Memolife to G.G., from the Paris Descartes university doctoral school Bio Sorbonne Paris Cité to L.-E. P., from the Centre National de la Recherche Scientifique, and from the Institut Pasteur to S.E.-M. and F.L., ANR-10-IDEX-0001-02/10-LABX-0054,MEMOLIFE,Memory in living systems: an integrated approach(2010), European Project: 683154,H2020-EU.1.1. - EXCELLENT SCIENCE - European Research Council (ERC),AstroWireSyn(2016), Labex MemoLife, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Polarité cellulaire, Migration et Cancer - Cell Polarity, Migration and Cancer, Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Service MIRCEN (MIRCEN), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie François JACOB (JACOB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie François JACOB (JACOB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Service MIRCEN (MIRCEN), Université Paris-Saclay-Institut de Biologie François JACOB (JACOB), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
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0301 basic medicine ,Mouse ,Connexin ,Fluorescent Antibody Technique ,CDC42 ,Hippocampal formation ,Development ,Hippocampus ,03 medical and health sciences ,symbols.namesake ,Mice ,0302 clinical medicine ,Laminin ,medicine ,Connexin 30 ,Animals ,Molecular Biology ,biology ,Polarity ,Brain ,Cell Polarity ,Golgi apparatus ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,Centrosome ,Astrocytes ,biology.protein ,symbols ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,sense organs ,Cell Migration Assays ,030217 neurology & neurosurgery ,Intracellular ,Developmental Biology ,Astrocyte ,Research Article - Abstract
Astrocytes undergo intense morphological maturation during development, changing from individual sparsely branched cells to polarized and tremendously ramified cells. Connexin 30, an astroglial gap-junction channel-forming protein expressed postnatally, regulates in situ the extension and ramification of astroglial processes. However, the involvement of connexin 30 in astroglial polarization, which is known to control cell morphology, remains unexplored. We found that connexin 30, independently of gap-junction-mediated intercellular biochemical coupling, alters the orientation of astrocyte protrusion, centrosome and Golgi apparatus during polarized migration in an in vitro wound-healing assay. Connexin 30 sets the orientation of astroglial motile protrusions via modulation of the laminin/β1 integrin/Cdc42 polarity pathway. Connexin 30 indeed reduces laminin levels, inhibits the redistribution of the β1-integrin extracellular matrix receptors, and inhibits the recruitment and activation of the small Rho GTPase Cdc42 at the leading edge of migrating astrocytes. In vivo, connexin 30, the expression of which is developmentally regulated, also contributes to the establishment of hippocampal astrocyte polarity during postnatal maturation. This study thus reveals that connexin 30 controls astroglial polarity during development., Summary: Connexin 30 sets the orientation of astroglial motile protrusions during polarized migration in vitro and contributes in vivo to the establishment of hippocampal astrocyte polarity during postnatal maturation.
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- 2018
119. mCCD
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A M, Assmus, M K, Mansley, L J, Mullins, A, Peter, and J J, Mullins
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Vacuolar Proton-Translocating ATPases ,Aquaporin 2 ,Cell Plasticity ,Epithelial Cells ,Editorial Focus ,Cell Line ,Clone Cells ,Amiloride ,Mice ,Phenotype ,Connexin 30 ,Electric Impedance ,Epithelial Sodium Channel Blockers ,Animals ,Kidney Tubules, Collecting ,Epithelial Sodium Channels ,Aldosterone - Abstract
The cortical collecting duct of the mammalian kidney plays a critical role in the regulation of body volume, sodium pH, and osmolarity and is composed of two distinct cells types, principal cells and intercalated cells. Each cell type is detectable in the kidney by the localization of specific transport proteins such as aquaporin 2 (Aqp2) and epithelial sodium channel (ENaC) in principal cells and V-ATPase B1 and connexin 30 (Cx30) in intercalated cells. mCCD
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- 2018
120. The connexin30 A88V mutant reduces cochlear gap junction expression and confers long-term protection against hearing loss
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John J. Kelly, Stephanie Hulme, Eric R. Press, Dale W. Laird, Julia M. Abitbol, and Brian L. Allman
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0301 basic medicine ,Hearing loss ,Mutant ,Mutation, Missense ,Connexin ,Biology ,Cell Line ,Mice ,Cell and Developmental Biology ,03 medical and health sciences ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,Animals ,Hearing Loss ,Cochlea ,Messenger RNA ,Gap junction ,Gap Junctions ,Cell Biology ,Mice, Mutant Strains ,Cell biology ,Hearing ,Mouse ,Cx30 ,GJB6 ,Clouston syndrome ,Aging ,030104 developmental biology ,medicine.anatomical_structure ,Amino Acid Substitution ,Gene Expression Regulation ,biology.protein ,sense organs ,Hair cell ,Anatomy ,medicine.symptom - Abstract
Mutations in the genes that encode the gap junction proteins connexin 26 (Cx26, encoded by GJB2) and Cx30 (GJB6) are the leading cause of hereditary hearing loss. That said, the Cx30 p.Ala88Val (A88V) mutant causes Clouston syndrome, but not hearing loss. Here, we report that the Cx30-A88V mutant, despite being toxic to inner ear-derived HEI-OC1 cells, conferred remarkable long-term protection against age-related high frequency hearing loss in Cx30(A88V/A88V) mice. During early development, there were no overt structural differences in the cochlea between genotypes, including a normal complement of hair cells; however, the supporting cell Cx30 gap junction plaques in mutant mice were reduced in size. In adulthood, Cx30(A88V/A88V) mutant mice had a reduction of cochlear Cx30 mRNA and protein, yet a full complement of hair cells. Conversely, the age-related high frequency hearing loss in Cx30(+/+) and Cx30(+/A88V) mice was due to extensive loss of outer hair cells. Our data suggest that the Cx30-A88V mutant confers long-term hearing protection and prevention of hair cell death, possibly via a feedback mechanism that leads to the reduction of total Cx30 gap junction expression in the cochlea.
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- 2018
121. Mechanistic effect of the human GJB6 gene and its mutations in HaCaT cell proliferation and apoptosis
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Li Zhang, Wenmin Liu, Yali Song, Wangli Wu, Rui-Li Zhang, Shuhua Zhou, Zhenying Wang, Lamei Chen, Nan Chen, Canan Ji, and Yuting Lu
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0301 basic medicine ,Physiology ,Immunology ,Mutant ,Biophysics ,Ocean Engineering ,Apoptosis ,Biochemistry ,Cell Line ,Flow cytometry ,030207 dermatology & venereal diseases ,03 medical and health sciences ,0302 clinical medicine ,Western blot ,Ectodermal Dysplasia ,medicine ,Connexin 30 ,Humans ,General Pharmacology, Toxicology and Pharmaceutics ,lcsh:QH301-705.5 ,Research Articles ,Cells, Cultured ,Cell Proliferation ,lcsh:R5-920 ,medicine.diagnostic_test ,integumentary system ,Chemistry ,Cell growth ,General Neuroscience ,Cell Biology ,General Medicine ,Transfection ,Flow Cytometry ,GJB6 gene ,Molecular biology ,Clouston syndrome ,Caspase ,HaCaT ,030104 developmental biology ,lcsh:Biology (General) ,Cell culture ,Caspases ,Doxycycline ,Mutation ,lcsh:Medicine (General) - Abstract
We constructed lentiviral vectors containing the human wild-type GJB6 gene and the mutant variants A88V and G11R. The three proteins were stably expressed by the Tet-on system in the HaCaT cell line and used to study the functional effect of the variants. The CCK-8 assay and flow cytometric analyses were used to determine the levels of cell proliferation and apoptosis. Western blot analyses were performed to analyze the relevant clinical indicators of hidrotic ectodermal dysplasia and markers of apoptosis in transfected HaCaT cells. The CCK8 assay and the flow cytometry results showed a significant increase (P
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- 2018
122. Blocking TNFalpha-driven astrocyte purinergic signaling restores normal synaptic activity during epileptogenesis
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Paola Nobili, Etienne Audinat, Ljiljana Nikolić, Anaïs Virenque, Weida Shen, Lauriane Ulmann, Laboratoire de Neurophysiologie et Nouvelles Microscopies (U1128), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Paris Descartes - Paris 5 (UPD5), Institut de Génomique Fonctionnelle (IGF), and Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
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Male ,0301 basic medicine ,[SDV]Life Sciences [q-bio] ,Hippocampus ,Mice, Transgenic ,Tetrodotoxin ,Biology ,Epileptogenesis ,Membrane Potentials ,Mice ,Receptors, Purinergic P2Y1 ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Epilepsy ,0302 clinical medicine ,Connexin 30 ,medicine ,Animals ,Autocrine signalling ,ComputingMilieux_MISCELLANEOUS ,Calcium signaling ,Neurons ,Kainic Acid ,Tumor Necrosis Factor-alpha ,Glutamate receptor ,Excitatory Postsynaptic Potentials ,Purinergic signalling ,medicine.disease ,Mice, Inbred C57BL ,Disease Models, Animal ,Luminescent Proteins ,030104 developmental biology ,medicine.anatomical_structure ,Epilepsy, Temporal Lobe ,Neurology ,Astrocytes ,Synapses ,Female ,Neuroscience ,030217 neurology & neurosurgery ,Signal Transduction ,Sodium Channel Blockers ,Astrocyte - Abstract
Epilepsy is characterized by unpredictable recurrent seizures resulting from abnormal neuronal excitability. Increasing evidence indicates that aberrant astrocyte signaling to neurons plays an important role in driving the network hyperexcitability, but the underlying mechanism that alters glial signaling in epilepsy remains unknown. Increase in glutamate release by astrocytes participates in the onset and progression of seizures. Epileptic seizures are also accompanied by increase of tumor necrosis factor alpha (TNFα), a cytokine involved in the regulation of astrocyte glutamate release. Here we tested whether TNFα controls abnormal astrocyte glutamate signaling in epilepsy and through which mechanism. Combining Ca2+ imaging, optogenetics, and electrophysiology, we report that TNFα triggers a Ca2+ -dependent glutamate release from astrocytes that boosts excitatory synaptic activity in the hippocampus through a mechanism involving autocrine activation of P2Y1 receptors by astrocyte-derived ATP/ADP. In a mouse model of temporal lobe epilepsy, such TNFα-driven astrocytic purinergic signaling is permanently active, promotes glial glutamate release, and drives abnormal synaptic activity in the hippocampus. Blocking this pathway by inhibiting P2Y1 receptors restores normal excitatory synaptic activity in the inflamed hippocampus. Our findings indicate that targeting the coupling of TNFα with astrocyte purinergic signaling may be a therapeutic strategy for reducing glial glutamate release and normalizing synaptic activity in epilepsy.
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- 2018
123. Astroglial Cx30 differentially impacts synaptic activity from hippocampal principal cells and interneurons.
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Hardy E, Cohen-Salmon M, Rouach N, and Rancillac A
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- Animals, Connexin 30 genetics, Connexin 30 metabolism, Interneurons metabolism, Mice, Synapses metabolism, Synaptic Transmission physiology, Astrocytes metabolism, Hippocampus cytology, Hippocampus metabolism
- Abstract
Astrocytes play important roles in brain function via dynamic structural and functional interactions with neurons. Yet the underlying mechanisms remain poorly defined. A typical feature of astrocytes is the high expression of connexins, which mediate their extensive intercellular communication and regulate their structural properties. In particular, connexin 30 (Cx30), one of the two connexins abundantly expressed by astrocytes, was recently shown to be a critical regulator of excitatory synaptic transmission by controlling the astroglial coverage of synapses. However, the role of Cx30 in the regulation of inhibitory synaptic transmission and excitatory/inhibitory balance remains elusive. Here, we investigated the role of astroglial Cx30 on the electrophysiological and morphological properties of five classes of hippocampal CA1 stratum oriens and pyramidale neurons, defined by the unsupervised Ward's clustering. Using Cx30 knockout mice, we found that Cx30 alters specific properties of some subsets of CA1 interneurons, such as resting membrane potential and sag ratio, while other parameters, such as action potential threshold and saturation frequency, were more frequently altered among the different classes of neurons. The excitation-inhibition balance was also differentially and selectively modulated among the different neuron subtypes. Only slight morphological differences were observed on reconstructed neurons. Altogether, these data indicate that Cx30 differentially alters the electrophysiological and morphological properties of hippocampal cell populations, and modulates both their excitatory and inhibitory inputs. Astrocytes, via Cx30, are thus active modulators of both excitatory and inhibitory synapses in the hippocampus., (© 2021 Wiley Periodicals LLC.)
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- 2021
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124. Tricellular adherens junctions provide a cell surface delivery platform for connexin 26/30 oligomers in the cochlea.
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Defourny, Jean and Thiry, Marc
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CELL membranes , *ADHERENS junctions , *CELL junctions , *OLIGOMERS , *COCHLEA , *GAIN-of-function mutations , *RECESSIVE genes - Abstract
• N-cadherin is exclusively present at tricellular junctions between adjacent GJPs. • Non-junctional Cx26/Cx30 oligomers are present at tricellular junction sites. • Tricellular adherens junctions are required for Cx26/Cx30 oligomer assembly into GJPs. In the cochlea, connexins 26 (Cx26) and 30 (Cx30) largely co-assemble into heteromeric gap junctions, which connect adjacent non-sensory epithelial cells. These channels are believed to ensure the rapid removal of K+ away from the base of sensory hair cells, resulting in K+ recycling back to the endolymph to maintain cochlear homeostasis. Many of the mutations in GJB2 and GJB6 , which encode CX26 and CX30, impair the formation of membrane channels and cause autosomal hearing loss in humans. Although recent advances have been made, several important questions remain about connexin trafficking and gap junction biogenesis. Here we show that tricellular adherens junctions present at the crossroad between adjacent gap junction plaques, provide an unexpected cell surface delivery platform for Cx26/Cx30 oligomers. Using an in situ proximity ligation assay, we detected the presence of non-junctional Cx26/Cx30 oligomers within lipid raft-enriched tricellular junction sites. In addition, we observed that cadherin homophilic interactions are critically involved in microtubule-mediated trafficking of Cx26/Cx30 oligomers to the cell surface. Overall, our results unveil an unexpected role for tricellular junctions in the trafficking and assembly of membrane channels. [ABSTRACT FROM AUTHOR]
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- 2021
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125. Mice with conditional deletion of Cx26 exhibit no vestibular phenotype despite secondary loss of Cx30 in the vestibular end organs
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Michelle D. Kappy, Yohei Takada, Min Young Lee, Tomoko Takada, Yehoash Raphael, Shannon Brewer, Lisa A. Beyer, W. Michael King, Ashley L. Godin, and Donald L. Swiderski
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Male ,Pathology ,medicine.medical_specialty ,Genotype ,Population ,Connexin ,Sensory system ,Biology ,Connexins ,Article ,Mice ,Hair Cells, Auditory ,Conditional gene knockout ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,Animals ,Inner ear ,education ,Cochlea ,Mice, Knockout ,Vestibular system ,education.field_of_study ,Microscopy, Confocal ,Gap Junctions ,Immunohistochemistry ,Sensory Systems ,Connexin 26 ,Mice, Inbred C57BL ,Phenotype ,medicine.anatomical_structure ,Microscopy, Fluorescence ,Mutation ,Female ,Vestibule, Labyrinth ,sense organs ,Hair cell ,Gene Deletion - Abstract
Connexins are components of gap junctions which facilitate transfer of small molecules between cells. One member of the connexin family, Connexin 26 (Cx26), is prevalent in gap junctions in sensory epithelia of the inner ear. Mutations of GJB2, the gene encoding Cx26, cause significant hearing loss in humans. The vestibular system, however, does not usually show significant functional deficits in humans with this mutation. Mouse models for loss of Cx26 function demonstrate hearing loss and cochlear pathology but the extent of vestibular dysfunction and organ pathology are less well characterized. To understand the vestibular effects of Cx26 mutations, we evaluated vestibular function and histology of the vestibular sensory epithelia in a conditional knockout (CKO) mouse with Cx26 loss of function. Transgenic C57BL/6 mice, in which cre-Sox10 drives excision of the Cx26 gene from non-sensory cells flanking the sensory epithelium of the inner ear (Gjb2-CKO), were compared to age-matched wild types. Animals were sacrificed at ages between 4 and 40 weeks and their cochlear and vestibular sensory organs harvested for histological examination. Cx26 immunoreactivity was prominent in the peripheral vestibular system and the cochlea of wild type mice, but absent in the Gjb2-CKO specimens. The hair cell population in the cochleae of the Gjb2-CKO mice was severely depleted but in the vestibular organs it was intact, despite absence of Cx26 expression. The vestibular organs appeared normal at the latest time point examined, 40 weeks. To determine whether compensation by another connexin explains survival of the normal vestibular sensory epithelium, we evaluated the presence of Cx30 in the Gjb2-CKO mouse. We found that Cx30 labeling was normal in the cochlea, but it was decreased or absent in the vestibular system. The vestibular phenotype of the mutants was not different from wild-types as determined by time on the rotarod, head stability tests and physiological responses to vestibular stimulation. Thus presence of Cx30 in the cochlea does not compensate for Cx26 loss, and the absence of both connexins from vestibular sensory epithelia is no more injurious than the absence of one of them. Further studies to uncover the physiological foundation for this difference between the cochlea and the vestibular organs may help in designing treatments for GJB2 mutations.
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- 2015
126. Novel mutations inGJB6andGJB2in Clouston syndrome
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W. H. Zeng, K. Guo, Songmei Geng, Yang Liu, Yale Liu, and J.‐G. Li
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Genetics ,Proband ,Ectodermal dysplasia ,Mutation ,Clouston syndrome ,Mutation, Missense ,Connexin ,Dermatology ,Middle Aged ,Biology ,medicine.disease ,medicine.disease_cause ,Connexins ,Connexin 26 ,Nail Diseases ,Ectodermal Dysplasia ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,biology.protein ,Humans ,Missense mutation ,Female ,Gene ,GJB6 - Abstract
Clouston syndrome (CS; also termed hidrotic ectodermal dysplasia) is a rare autosomal dominant genetic skin disorder, characterized by alopecia, nail dystrophy, and palmoplantar hyperkeratosis. Mutations in the GJB6 gene, which encodes the gap junction protein connexin 30, have been shown to cause this disorder. To date, four mutations of GJB6 have been found in patients with CS: G11R, V37E, D50N and A88V. Mutations in GJA1 (V41L) and GJB2 (R127H) are also related to CS. We found a novel missense mutation, N14S, in GJB6 and the previously identified F191L mutation in GJB2 (Cx26) in a proband with CS in a Han Chinese pedigree; these mutations were not found in 200 ethnically matched nonconsanguineous Han Chinese controls.
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- 2015
127. Single Nucleotide Polymorphisms of theGJB2andGJB6Genes Are Associated with Autosomal Recessive Nonsyndromic Hearing Loss
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Ruan Felipe Vieira Medrano, Ana Paula Grillo, Edi Lúcia Sartorato, Flávia Marcorin de Oliveira, Sueli Matilde da Silva-Costa, Camila Andréa de Oliveira, and Gabriela Queila de Carvalho
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Male ,Article Subject ,Hearing loss ,lcsh:Medicine ,Single-nucleotide polymorphism ,Locus (genetics) ,Deafness ,Polymorphism, Single Nucleotide ,Connexins ,General Biochemistry, Genetics and Molecular Biology ,DNA sequencing ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,Humans ,Allele ,Gene ,Genetics ,General Immunology and Microbiology ,biology ,lcsh:R ,Genetic Diseases, Inborn ,General Medicine ,Phenotype ,Molecular biology ,Connexin 26 ,Genetic Loci ,biology.protein ,Female ,medicine.symptom ,GJB6 ,Research Article - Abstract
Single nucleotide polymorphisms (SNPs) are important markers in many studies that link DNA sequence variations to phenotypic changes; such studies are expected to advance the understanding of human physiology and elucidate the molecular basis of diseases. TheDFNB1locus, which contains theGJB2andGJB6genes, plays a key role in nonsyndromic hearing loss. Previous studies have identified important mutations in this locus, but the contribution of SNPs in the genes has not yet been much investigated. The aim of this study was to investigate the association of nine polymorphisms located within theDFNB1locus with the occurrence of autosomal recessive nonsyndromic hearing loss (ARNSHL). The SNPs rs3751385 (C/T), rs7994748 (C/T), rs7329857 (C/T), rs7987302 (G/A), rs7322538 (G/A), rs9315400 (C/T), rs877098 (C/T), rs945369 (A/C), and rs7333214 (T/G) were genotyped in 122 deaf patients and 132 healthy controls using allele-specific PCR. There were statistically significant differences between patients and controls, in terms of allelic frequencies in the SNPs rs3751385, rs7994748, rs7329857, rs7987302, rs945369, and rs7333214 (P<0.05). No significant differences between the two groups were observed for rs7322538, rs9315400, and rs877098. Our results suggest that SNPs present in theGJB2andGJB6genes may have an influence on ARNSHL in humans.
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- 2015
128. Connexin26 (GJB2) deficiency reduces active cochlear amplification leading to late-onset hearing loss
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Y. Zhu, J. Chen, C. Liang, L. Zong, R.O. Jones, and H.-B. Zhao
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medicine.medical_specialty ,Patch-Clamp Techniques ,Hearing loss ,Endocochlear potential ,Otoacoustic Emissions, Spontaneous ,Otoacoustic emission ,Fluorescent Antibody Technique ,Cell Count ,Audiology ,Electric Capacitance ,Severity of Illness Index ,Article ,Connexins ,Conditional gene knockout ,Connexin 30 ,otorhinolaryngologic diseases ,Animals ,Medicine ,Inner ear ,Age of Onset ,Hearing Loss ,Cochlea ,Mice, Knockout ,business.industry ,General Neuroscience ,Connexin 26 ,Hair Cells, Auditory, Outer ,medicine.anatomical_structure ,Disease Progression ,Hair cell ,medicine.symptom ,business ,Auditory fatigue - Abstract
Connexin26 (Cx26, GJB2) mutations account for >50% of nonsyndromic hearing loss. The deafness is not always congenital. A large group of these patients (~30%) demonstrate a late-onset hearing loss, starting in childhood. They have normal hearing early in life and are therefore good candidates for applying protective and therapeutic interventions. However, the underlying deafness mechanism is unclear. In this study, we used a time-controlled, inducible gene knockout technique to knockout Cx26 expression in the cochlea after birth. We found that deletion of Cx26 after postnatal day 5 (P5) in mice could lead to late-onset hearing loss. Similar to clinical observations, the mice demonstrated progressive, mild to moderate hearing loss. The hearing loss initiated at high frequencies and then extended to the middle- and low-frequency range. The cochlea showed normal development and had no apparent hair cell loss. However, distortion product otoacoustic emission (DPOAE) was reduced. The reduction was also progressive and large at high-frequencies. Consistent with DPOAE reduction, we found that outer hair cell electromotility associated nonlinear capacitance was shifted to the right and the slope of voltage dependence was reduced. The endocochlear potential was reduced in Cx26 conditional knockout (cKO) mice but the reduction was not associated with progressive hearing loss. These data suggest that Cx26 deficiency may impair active cochlear amplification leading to late-onset hearing loss. Our study also helps develop newer protective and therapeutic interventions to this common nonsyndromic hearing loss.
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- 2015
129. New and Rare GJB2 Alleles in Patients with Nonsyndromic Sensorineural Hearing Impairment: A Genotype/Auditory Phenotype Correlation
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Maria C. Guarnaccia, Anna Ravani, Cristina Falcinelli, Ilaria Stanghellini, Antonio Percesepe, Elisabetta Genovese, and Silvia Palma
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Male ,Heterozygote ,medicine.medical_specialty ,Hearing loss ,Hearing Loss, Sensorineural ,Population ,Biology ,Compound heterozygosity ,gene testing ,GJB2 ,Connexins ,Loss of heterozygosity ,Gene Frequency ,Genotype ,Connexin 30 ,medicine ,Humans ,Point Mutation ,education ,Allele frequency ,Alleles ,Genetics (clinical) ,Genetics ,education.field_of_study ,General Medicine ,Connexin 26 ,Phenotype ,biology.protein ,Medical genetics ,Female ,medicine.symptom ,GJB6 - Abstract
The aim of the study is to report the new and rare GJB2 variants identified in individuals with nonsyndromic sensorineural hearing impairment (HI) in a retrospective study based on 498 patients referred to the Otolaryngology and Medical Genetics Units of the Modena University Hospital, Italy, with the purpose of building new genotype/auditory phenotype correlations for the GJB2 gene.A total of eight variants identified in HI patients under study were considered rare for their frequency below 1% in the general population and in the HI databases. Of those, four (I20T, V95M, N206S, c.-22-2AC) were in compound heterozygosity with known mutations resulting in a range of phenotypes from mild to profound, whereas four (W3R, C218Y, K221N, c.-22-6TC) were found in simple heterozygosity (for those only in silico prediction of pathogenicity was possible due to the absence of a second GJB2 or GJB6 mutation).Based on patients' phenotype, reported frequency, and in silico prediction analysis, we suggest the prognostic value of eight rare and new GJB2 alleles, which may be of help to the clinician in counseling patients who carry such variants.
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- 2014
130. Engraftment of Human Pluripotent Stem Cell-derived Progenitors in the Inner Ear of Prenatal Mice
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Toru Miwa, Makoto Hosoya, Ryosei Minoda, Hideyuki Okano, Tsubasa Saeki, Hiroki Takeda, Chika Saegusa, and Masato Fujioka
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0301 basic medicine ,Pluripotent Stem Cells ,Induced Pluripotent Stem Cells ,lcsh:Medicine ,Cell Count ,Biology ,Congenital hearing loss ,Article ,03 medical and health sciences ,medicine ,Connexin 30 ,Animals ,Humans ,Inner ear ,Progenitor cell ,Induced pluripotent stem cell ,lcsh:Science ,Cochlea ,Cells, Cultured ,Mice, Knockout ,Multidisciplinary ,lcsh:R ,Embryo ,Embryo, Mammalian ,Embryonic stem cell ,Transplantation ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,Ear, Inner ,Cancer research ,lcsh:Q ,Female ,Stem Cell Transplantation - Abstract
There is, at present, no curative treatment for genetic hearing loss. We have previously reported that transuterine gene transfer of wild type CONNEXIN30 (CX30) genes into otocysts in CX30-deleted mice could restore hearing. Cell transplantation therapy might be another therapeutic option, although it is still unknown whether stem cell-derived progenitor cells could migrate into mouse otocysts. Here, we show successful cell transplantation of progenitors of outer sulcus cell-like cells derived from human-derived induced pluripotent stem cells into mouse otocysts on embryonic day 11.5. The delivered cells engrafted more frequently in the non-sensory region in the inner ear of CX30-deleted mice than in wild type mice and survived for up to 1 week after transplantation. Some of the engrafted cells expressed CX30 proteins in the non-sensory region. This is the first report that demonstrates successful engraftment of exogenous cells in prenatal developing otocysts in mice. Future studies using this mouse otocystic injection model in vivo will provide further clues for developing treatment modalities for congenital hearing loss in humans.
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- 2017
131. Plasticity of astroglial networks in the cerebral cortex of the rat: response to environmental enrichment and physicochemical variables
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Santacroce, Ignacio, Colombo, Jorge Augusto, and Rela, Lorena
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CONNEXIN43 ,CONNEXIN 30 ,ASTROGLIAL NETWORKS ,CORTEZA MOTORA ,UNIONES GAP ,ASTROCITOS ,CONEXINA 30 ,CONEXINA 43 ,ASTROCYTES ,REDES ASTROGLIALES ,GAP JUNCTIONS ,GLIA ,PLASTICIDAD ,ENRIQUECIMIENTO AMBIENTAL ,PLASTICITY ,MOTOR CORTEX ,ENVIRONMENTAL ENRICHMENT - Abstract
El enriquecimiento ambiental favorece tanto el desempeño conductual en pruebas de aprendizaje motor como la recuperación de comportamientos motores afectados en modelos de injuria de la corteza motora. La mejoría ha sido generalmente asociada a plasticidad neuronal. Observaciones recientes han puesto de manifiesto el rol protagónico que llevan a cabo las redes astrogliales en la fisiología de la corteza cerebral y otras regiones cerebrales. En esta Tesis se analizan los efectos del enriquecimiento ambiental sobre la configuración de las redes astrogliales en la corteza motora, a los fines de ampliar el conocimiento de los mecanismos que subyacen a la neuroplasticidad, con potenciales implicancias en el diseño de abordajes terapéuticos. En ella se evalúa el impacto del enriquecimiento ambiental sobre los patrones de expresión de marcadores inmunohistoquímicos neuronales y astrogliales asociados a procesos de plasticidad en la corteza motora de la rata, así como sobre la configuración de las redes de acoplamiento astroglial, mediante experimentos de dye-coupling realizados en rebanadas frescas de cerebro. Los resultados obtenidos muestran que en condiciones control las redes de acoplamiento astroglial en la lámina I exhiben una mayor densidad celular que en la lámina II-III. Se describe, asimismo, la implementación de un modelo de enriquecimiento ambiental cuyo efecto es compatible con la inducción de una expansión selectiva del gliopilo cortical en las láminas II-III, acompañada de una reducción generalizada de la densidad de marca de conexina 30 en ambas láminas. Los hallazgos muestran que la plasticidad inducida en la corteza motora por exposición a enriquecimiento ambiental involucra cambios a nivel de las redes de acoplamiento astroglial, constituyendo un posible mecanismo mediante el cual el componente astroglial podría participar en la recuperación observada en patologías inducidas por injurias mecánicas, cerebrovasculares u otras. Exposure to an enriched environment improves recovery of behavioral performance in motor learning and in motor function in animal models of motor cortex injury. This improvement has been generally associated with neuronal plasticity. Recent observations have revealed a crucial role of astrocyte networks in the physiology of central nervous system circuits. This Thesis presents a study of the effects of environmental enrichment on the structure and function of astroglial networks of the motor cortex, aiming at improving knowledge regarding possible mechanisms with potential therapeutic application. The effects of environmental enrichment on the patterns of neuronal and glial markers expression, associated with cortical plasticity, were analyzed using immunohistochemical labeling in fixed tissue and dye coupling procedures in acute, fresh, brain slices. The latter was applied in order to evaluate the effects of environmental enrichment on the connectivity and structure of astroglial networks.The results show that in control conditions astroglial networks have a higher cell density in layer I than in layers II-III. In addition, we present a model of environmental enrichment with effects compatible with a selective expansion of the cortical gliopil in layers II-III, associated with a generalized reduction in the expression of connexin 30 in both layers. These findings show that the neuroplasticity induced in the motor cortex by environmental enrichment involves changes at the level of astroglial networks, suggestive of the involvement of these networks in the recovery process following damage. Fil: Santacroce, Ignacio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
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- 2017
132. Subcellular reorganization and altered phosphorylation of the astrocytic gap junction protein connexin43 in human and experimental temporal lobe epilepsy
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Christian Steinhäuser, Michel K. Herde, Martin K. Schwarz, Tingsong Li, Peter Bedner, Tushar Deshpande, Albert J. Becker, Hartmut Vatter, and Christian Henneberger
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0301 basic medicine ,Male ,Pathology ,Hippocampal formation ,Hippocampus ,metabolism [Platelet Endothelial Cell Adhesion Molecule-1] ,Mice ,0302 clinical medicine ,metabolism [Connexin 30] ,Excitatory Amino Acid Agonists ,Perivascular space ,metabolism [Antigens] ,Cellular localization ,pathology [Astrocytes] ,chemically induced [Epilepsy, Temporal Lobe] ,chondroitin sulfate proteoglycan 4 ,Kainic Acid ,medicine.diagnostic_test ,metabolism [Proteoglycans] ,ultrastructure [Cell Membrane] ,Gap junction ,Cell biology ,Up-Regulation ,Platelet Endothelial Cell Adhesion Molecule-1 ,medicine.anatomical_structure ,Neurology ,Phosphorylation ,Female ,Proteoglycans ,Astrocyte ,Subcellular Fractions ,medicine.medical_specialty ,pathology [Epilepsy, Temporal Lobe] ,Mice, Transgenic ,S100 Calcium Binding Protein beta Subunit ,Biology ,metabolism [Cell Membrane] ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Western blot ,Glial Fibrillary Acidic Protein ,medicine ,toxicity [Excitatory Amino Acid Agonists] ,Connexin 30 ,Animals ,Humans ,metabolism [S100 Calcium Binding Protein beta Subunit] ,ddc:610 ,Antigens ,Hippocampal sclerosis ,Cell Membrane ,metabolism [Glial Fibrillary Acidic Protein] ,GJB6 protein, human ,medicine.disease ,metabolism [Connexin 43] ,physiology [Up-Regulation] ,metabolism [Subcellular Fractions] ,Disease Models, Animal ,030104 developmental biology ,pathology [Hippocampus] ,Epilepsy, Temporal Lobe ,Astrocytes ,Connexin 43 ,genetics [Connexin 43] ,ultrastructure [Astrocytes] ,toxicity [Kainic Acid] ,030217 neurology & neurosurgery - Abstract
Dysfunctional astrocytes are increasingly recognized as key players in the development and progression of mesial temporal lobe epilepsy (MTLE). One of the dramatic changes astrocytes undergo in MTLE with hippocampal sclerosis (HS) is loss of gap junction coupling. To further elucidate molecular mechanism(s) underlying this alteration, we assessed expression, cellular localization and phosphorylation status of astrocytic gap junction proteins in human and experimental MTLE-HS. In addition to conventional confocal analysis of immunohistochemical staining we employed expansion microscopy, which allowed visualization of blood-brain-barrier (BBB) associated cellular elements at a sub-µm scale. Western Blot analysis showed that plasma membrane expression of connexin43 (Cx43) and Cx30 were not significantly different in hippocampal specimens with and without sclerosis. However, we observed a pronounced subcellular redistribution of Cx43 toward perivascular endfeet in HS, an effect that was accompanied by increased plaque size. Furthermore, in HS Cx43 was characterized by enhanced C-terminal phosphorylation of sites affecting channel permeability. Prominent albumin immunoreactivity was found in the perivascular space of HS tissue, indicating that BBB damage and consequential albumin extravasation was involved in Cx43 dysregulation. Together, our results suggest that subcellular reorganization and/or abnormal posttranslational processing rather than transcriptional downregulation of astrocytic gap junction proteins account for the loss of coupling reported in human and experimental TLE. The observations of the present study provide new insights into pathological alterations of astrocytes in HS, which may aid in the identification of novel therapeutic targets and development of alternative anti-epileptogenic strategies.
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- 2017
133. Implication of connexin30 on the stemness of glioma: connexin30 reverses the malignant phenotype of glioma by modulating IGF-1R, CD133 and cMyc
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Sankaradoss Arun, Shantha Ravisankar, and Arambakkam Janardhanam Vanisree
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0301 basic medicine ,Adult ,Male ,Cancer Research ,Pathology ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Biology ,Transfection ,Proto-Oncogene Proteins c-myc ,03 medical and health sciences ,Young Adult ,In vivo ,Glioma ,Cell Line, Tumor ,medicine ,Connexin 30 ,Animals ,Humans ,AC133 Antigen ,Rats, Wistar ,Receptor ,neoplasms ,Aged ,Brain Neoplasms ,Growth factor ,Brain ,Receptors, Somatomedin ,Middle Aged ,medicine.disease ,In vitro ,Gene Expression Regulation, Neoplastic ,030104 developmental biology ,Neurology ,Oncology ,Cancer research ,Neoplastic Stem Cells ,Neurology (clinical) ,Stem cell ,Intracellular ,Neoplasm Transplantation - Abstract
Gap-junctional intercellular communication (GJIC) plays a major role in the malignant growth of glioma. Although the mechanistic aspects of GJIC have been extensively studied, the role of connexins in the regulation of the malignant behavior of glioma stem cells (GSCs) remains unclear. In our previous studies, we have shown that connexin30 can interfere with the insulin-like growth factor 1 receptor (IGF-1R), which is known for self-renewal and pluripotency. Following our earlier in vitro observation, in this work, we aimed to study the consequence of this influence of Cx30 on IGF-1R by evaluating the marker of GSCs, CD133 and oncoprotein, cMyc. We strengthened our basis by examining human glioma samples of different grades as well as rat C6 xenografts (Cx30-transfected and -non-transfected C6 cells) along with the sphere formation assays in vitro. Investigation of stemness-related CD133 and cMyc in human samples and rat xenografts exhibited a reciprocal relationship between Cx30 and IGF-1R in the low and high grades (HG) of glioma. Cx30 was completely abolished in HG; levels of IGF-1R, CD133 and cMyc expression were positively correlated with HG. Cx30 transfection could attenuate the malignant burden of glioma in rat xenografts. Cx30 transfection also altered the tumor sphere formation of C6 glioma cells in vitro, an important property of GSCs, and there was a significant reduction of CD133 and cMyc expression by Cx30 both in vitro and in vivo. These factors indicate that dysfunction of Cx30 plays a crucial role in the prevention of the stemness of glioma, and the exploitation of this feature will help in the management of glioma.
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- 2017
134. Targeted deletion of Aqp4 promotes the formation of astrocytic gap junctions
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Mahmood Amiry-Moghaddam, Soulmaz Rahmani, Shirin Katoozi, Ole Petter Ottersen, Nadia Skauli, Laura M. A. Camassa, and Henning B. Boldt
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0301 basic medicine ,Male ,Histology ,Green Fluorescent Proteins ,Connexin ,Mice, Transgenic ,Connexins ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Western blot ,Glial Fibrillary Acidic Protein ,medicine ,Connexin 30 ,Animals ,Microscopy, Immunoelectron ,Adenosine Triphosphatases ,Aquaporin 4 ,Syncytium ,Microscopy, Confocal ,medicine.diagnostic_test ,Glial fibrillary acidic protein ,biology ,General Neuroscience ,Gap junction ,Brain ,Gap Junctions ,Cell biology ,Mice, Inbred C57BL ,030104 developmental biology ,Ion homeostasis ,medicine.anatomical_structure ,Biochemistry ,Gene Expression Regulation ,Astrocytes ,Connexin 43 ,biology.protein ,sense organs ,Anatomy ,030217 neurology & neurosurgery ,Astrocyte - Abstract
Aquaporin-4 (AQP4) is the predominant water channel in the brain and is expressed in high density in astrocytes. By fluxing water along osmotic gradients, AQP4 contributes to brain volume and ion homeostasis. Here we ask whether deletion of Aqp4 leads to upregulation of the gap junctional proteins connexin-43 (Cx43) and connexin-30 (Cx30). These molecules couple adjacent astrocytes to each other and allow water and ions to redistribute within the astrocyte syncytium. Immunogold analysis of parietal cortex and hippocampus showed that the number of gap junctions per capillary profile is increased in AQP4 knockout (AQP4 KO) mice. The most pronounced changes were observed for Cx43 in hippocampus where the number of connexin labeled gap junctions increased by 100% following AQP4 KO. Western blot analysis of whole tissue homogenates showed no change in the amount of Cx43 or Cx30 protein after AQP4 KO. However, AQP4 KO led to a significant increase in the amount of Cx43 in a Triton X-100 insoluble fraction. This fraction is associated with connexin assembly into gap junctional plaques in the plasma membrane. In line with our immunoblot data, RT-qPCR showed no significant increase in Cx43 and Cx30 mRNA levels after AQP4 KO. Our findings suggest that AQP4 KO leads to increased aggregation of Cx43 into gap junctions and provide a putative mechanistic basis for the enhanced tracer coupling in hippocampi of AQP4 KO mice. The increased number of gap junctions in AQP4 deficient mice may explain why Aqp4 deletion has rather modest effects on brain volume and K+ homeostasis.
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- 2017
135. Corrigendum: A connexin30 mutation rescues hearing and reveals roles for gap junctions in cochlear amplification and micromechanics
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Ian J. Russell, Andrei N. Lukashkin, Victoria A. Lukashkina, Snezana Levic, and Nicola Strenzke
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Male ,0301 basic medicine ,Science ,Mutation, Missense ,General Physics and Astronomy ,Library science ,Connexins ,General Biochemistry, Genetics and Molecular Biology ,Article ,German ,Mice ,03 medical and health sciences ,Hearing ,Species Specificity ,Political science ,Connexin 30 ,otorhinolaryngologic diseases ,Animals ,Multidisciplinary ,Gap Junctions ,General Chemistry ,Medical research ,Corrigenda ,Basilar Membrane ,language.human_language ,Cochlea ,Hair Cells, Auditory, Outer ,030104 developmental biology ,Mutation (genetic algorithm) ,Cochlear Microphonic Potentials ,Mice, Inbred CBA ,language ,Female ,sense organs - Abstract
Accelerated age-related hearing loss disrupts high-frequency hearing in inbred CD-1 mice. The p.Ala88Val (A88V) mutation in the gene coding for the gap-junction protein connexin30 (Cx30) protects the cochlear basal turn of adult CD-1Cx30A88V/A88V mice from degeneration and rescues hearing. Here we report that the passive compliance of the cochlear partition and active frequency tuning of the basilar membrane are enhanced in the cochleae of CD-1Cx30A88V/A88V compared to CBA/J mice with sensitive high-frequency hearing, suggesting that gap junctions contribute to passive cochlear mechanics and energy distribution in the active cochlea. Surprisingly, the endocochlear potential that drives mechanoelectrical transduction currents in outer hair cells and hence cochlear amplification is greatly reduced in CD-1Cx30A88V/A88V mice. Yet, the saturating amplitudes of cochlear microphonic potentials in CD-1Cx30A88V/A88V and CBA/J mice are comparable. Although not conclusive, these results are compatible with the proposal that transmembrane potentials, determined mainly by extracellular potentials, drive somatic electromotility of outer hair cells., A point mutation in the gap-junction protein connexin 30 stops early onset age-related hearing loss. Here, the authors show that gap junctions contribute to cochlear micromechanics and that cochlear amplification is likely controlled by extracellular potentials in vicinity of the cochlear sensory cells.
- Published
- 2017
136. Connexin-Mediated Signaling in Nonsensory Cells Is Crucial for the Development of Sensory Inner Hair Cells in the Mouse Cochlea
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Johnson, S.L., Ceriani, F., Houston, O., Polishchuk, R., Polishchuk, E., Crispino, G., Zorzi, V., Mammano, F., and Marcotti, W.
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Male ,Mice, Knockout ,Hair Cells, Auditory, Inner ,Neuroscience (all) ,Action Potentials ,Gap-junction ,Mice, Transgenic ,Connexin ,Deafness ,Development ,Connexins ,Cochlea ,Inner hair cells ,Connexin 26 ,Mice ,Connexin 30 ,otorhinolaryngologic diseases ,Animals ,Female ,sense organs ,Research Articles ,Signal Transduction ,Cellular/Molecular - Abstract
Mutations in the genes encoding for gap junction proteins connexin 26 (Cx26) and connexin 30 (Cx30) have been linked to syndromic and nonsyndromic hearing loss in mice and humans. The release of ATP from connexin hemichannels in cochlear nonsensory cells has been proposed to be the main trigger for action potential activity in immature sensory inner hair cells (IHCs), which is crucial for the refinement of the developing auditory circuitry. Using connexin knock-out mice, we show that IHCs fire spontaneous action potentials even in the absence of ATP-dependent intercellular Ca(2+) signaling in the nonsensory cells. However, this signaling from nonsensory cells was able to increase the intrinsic IHC firing frequency. We also found that connexin expression is key to IHC functional maturation. In Cx26 conditional knock-out mice (Cx26(Sox10-Cre)), the maturation of IHCs, which normally occurs at approximately postnatal day 12, was partially prevented. Although Cx30 has been shown not to be required for hearing in young adult mice, IHCs from Cx30 knock-out mice exhibited a comprehensive brake in their development, such that their basolateral membrane currents and synaptic machinery retain a prehearing phenotype. We propose that IHC functional differentiation into mature sensory receptors is initiated in the prehearing cochlea provided that the expression of either connexin reaches a threshold level. As such, connexins regulate one of the most crucial functional refinements in the mammalian cochlea, the disruption of which contributes to the deafness phenotype observed in mice and DFNB1 patients. SIGNIFICANCE STATEMENT: The correct development and function of the mammalian cochlea relies not only on the sensory hair cells, but also on the surrounding nonsensory cells. Although the nonsensory cells have been largely implicated in the general homeostasis in the mature cochlea, their involvement in the initial functional differentiation of the sensory inner hair cells is less clear. Using mutant mouse models for the most common form of congenital deafness in humans, which are knock-outs for the gap-junction channels connexin 26 and connexin 30 genes, we show that defects in nonsensory cells prevented the functional maturation of inner hair cells. In connexin knock-outs, inner hair cells remained stuck at a prehearing stage of development and, as such, are unable to process sound information.
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- 2017
137. In Search of Genetic Markers for Nonsyndromic Deafness in Africa: A Study in Cameroonians and Black South Africans with the GJB6 and GJA1 Candidate Genes
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Kamogelo Lebeko, Nomlindo Makubalo, Collet Dandara, Ambroise Wonkam, Jason Bosch, and Jean Jacques Noubiap Nziale
- Subjects
Genetic Markers ,Male ,Candidate gene ,Adolescent ,Genotype ,Hearing loss ,Black People ,Deafness ,Biology ,Biochemistry ,Connexins ,Young Adult ,symbols.namesake ,Genetic variation ,Connexin 30 ,otorhinolaryngologic diseases ,Genetics ,medicine ,Humans ,Genetic Predisposition to Disease ,Cameroon ,Nonsyndromic deafness ,Age of Onset ,Child ,Molecular Biology ,Sanger sequencing ,Genetic Variation ,Original Articles ,medicine.disease ,Connexin 26 ,Connexin 43 ,symbols ,biology.protein ,Molecular Medicine ,Female ,medicine.symptom ,Age of onset ,Gene Deletion ,GJB6 ,Biotechnology - Abstract
Deafness is the most common sensory disability in the world and has a variety of causes. Globally, mutations in GJB2 have been shown to play a major role in nonsyndromic deafness, but this has not been seen in Africans. Two other connexin genes, GJB6 and GJA1, have been implicated in hearing loss but have seldom been investigated in African populations. We set out to investigate the role of genetic variation in GJB6 and GJA1 in a group of Cameroonian and South African Blacks with nonsyndromic recessive hearing loss. A subset of 100 patients, affected with nonsyndromic hearing loss, from a cohort that was previously shown not to have GJB2 mutation, was analyzed by Sanger sequencing of the entire coding regions of GJB6 and GJA1. In addition, the large-scale GJB6-D3S1830 deletion was also investigated. No pathogenic mutation was detected in either GJB6 or GJA1, nor was the GJB6-D3S1830 deletion detected. There were no statistically significant differences in sequence variants between patients and controls. Mutations in GJB6 and GJA1 are not a major cause of nonsyndromic deafness in this group of Africans from Cameroon and South Africa. Currently, there is no sufficient evidence to support their testing in a clinical setting for individuals of African ancestry.
- Published
- 2014
138. Particular distribution of the GJB2/GJB6 gene mutations in Mexican population with hearing impairment
- Author
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Sergio A. Cuevas-Covarrubias, Francisco Loeza-Becerra, Mirna Martínez-Saucedo, Héctor Urueta-Cuellar, Luz María González-Huerta, Pedro Berrruecos-Villalobos, and M.R. Rivera-Vega
- Subjects
Adult ,Male ,Heterozygote ,Adolescent ,Hearing loss ,Hearing Loss, Sensorineural ,Gene mutation ,medicine.disease_cause ,Connexins ,Young Adult ,Gene Frequency ,Genotype ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,Humans ,Allele ,Child ,Mexico ,Genetics ,Mutation ,biology ,Genetic heterogeneity ,business.industry ,Homozygote ,Infant, Newborn ,Infant ,Sequence Analysis, DNA ,General Medicine ,medicine.disease ,Connexin 26 ,Otorhinolaryngology ,Child, Preschool ,Pediatrics, Perinatology and Child Health ,biology.protein ,Female ,Sensorineural hearing loss ,medicine.symptom ,business ,GJB6 - Abstract
Background Hereditary sensorineural hearing loss (SNHL) is a genetically heterogeneous disorder worldwide. Mutations in the GJB2 gene are a frequent cause of hereditary SNHL. There is a prevalence of certain mutations in various populations which suggests that specific mutations may be influenced by ethnic background. Objective To analyze the prevalence of GJB2 , GJB6 mutations in several geographic areas of Mexico in patients with hereditary SNHL. Materials and methods One hundred and forty Mexican unrelated propositi with prelingual SNHL were included in the study. All patients had three previous generations born in Mexico and belonged to no specific ethnic group. Analyses of the GJB2 and GJB6 genes and mt.1555A Results Twenty-three homozygous mutations, 57 heterozygous mutations, 1 double heterozygous ( GJB2 / GJB6 ) and 59 wild-type genotypes in the GJB2 gene were observed. Three patients had the homozygous c.del35 mutation whereas 26 patients were heterozygous for this gene defect. Only one patient with the GJB6 gene deletion was present (it includes the double heterozygous GJB2 / GJB6 ). The mt.1555A > G mutation was not detected. Conclusion We found a great variety of mutations depending on the analyzed region in patients with SNHL; 57.86% of patients had affection in one or two alleles in GJB2 or GJB6 genes whereas 42.14% were wild-type. In some cases, allele distribution depended on region. Molecular studies of more genes involved in hereditary non-syndromic SNHL are required to completely confirm the molecular basis of hearing loss in Mexican population.
- Published
- 2014
139. The Clouston syndrome mutation connexin30 A88V leads to hyperproliferation of sebaceous glands and hearing impairments in mice
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Klaus Willecke, Anna Beinhauer, Felicitas Bosen, Thomas Franz, Nicola Strenzke, and Melanie Schütz
- Subjects
Sebaceous gland ,Ectodermal dysplasia ,medicine.medical_specialty ,Pathology ,Transgenic mouse line ,Gap junction ,Mutant ,Mutation, Missense ,Biophysics ,Connexin ,Mice, Transgenic ,Biology ,medicine.disease_cause ,Biochemistry ,Connexins ,Mice ,Sebaceous Glands ,Ectodermal Dysplasia ,Structural Biology ,Internal medicine ,Connexin 30 ,Genetics ,medicine ,Animals ,Humans ,Hearing Loss ,Molecular Biology ,Cells, Cultured ,Genetic Association Studies ,Cell Proliferation ,Mutation ,Point mutation ,Epidermis (botany) ,Cell Membrane ,Cell Biology ,medicine.disease ,Clouston syndrome ,3. Good health ,medicine.anatomical_structure ,Endocrinology ,Hair Follicle ,Connexin30 ,Homeostasis - Abstract
Distinct mutations in the gap junction protein connexin30 (Cx30) can cause the ectodermal dysplasia Clouston syndrome in humans. We have generated a new mouse line expressing the Clouston syndrome mutation Cx30A88V under the control of the endogenous Cx30 promoter. Our results show that the mutated Cx30A88V protein is incorporated in gap junctional plaques of the epidermis. Homozygous Cx30A88V mice reveal hyperproliferative and enlarged sebaceous glands as well as a mild palmoplantar hyperkeratosis. Additionally, homozygous mutant mice show an altered hearing profile compared to control mice. We conclude that the Cx30A88V mutation triggers hyperproliferation in the skin and changes the cochlear homeostasis in mice.
- Published
- 2014
140. Expression of gap junction proteins connexins 26, 30, and 43 in Dupuytren’s disease
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Andrej Cör, Lukas A. Holzer, and Gerold Holzer
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Gap Junction Proteins ,Adult ,Male ,Pathology ,medicine.medical_specialty ,Disease ,Severity of Illness Index ,Connexins ,Palmar aponeurosis ,Connexin 30 ,Medicine ,Humans ,Orthopedics and Sports Medicine ,Actin ,Muscle actin ,Aged ,Aged, 80 and over ,business.industry ,Gap junction ,Mean age ,General Medicine ,Middle Aged ,Actins ,Connexin 26 ,Dupuytren Contracture ,medicine.anatomical_structure ,Case-Control Studies ,Surgery ,Female ,Spine, Shoulder and Hand ,business ,Wound healing - Abstract
Background and purpose Dupuytren’s disease (DD) is a benign fibroproliferative process of the palmar aponeurosis showing similarities to wound healing. Communication of cells involved in wound healing is mediated by the composition of gap junction (GJ) proteins. We investigated the expression of 3 GJ proteins, connexins 26, 30, and 43 (Cx26, Cx30, and Cx43) in DD. Patients and methods Fragments of Dupuytren’s tissue from 31 patients (mean age 56 (30–76) years, 24 male) were analyzed immunohistochemically and compared to control tissue for expression of the GJ proteins Cx26, Cx30, and Cx43 and also alfa-smooth muscle actin (α-SMA). Results 14 of 31 samples could be attributed to the involutional phase (α-SMA positive) whereas 17 samples had to be considered cords in the residual phase (α-SMA negative). Expression of Cx26 and Cx43 was seen in 12 of the 14 samples from the involutional phase, and Cx30 was seen in 7 of these. Only 4 of the 17 samples from the residual phase showed any Cx, and there was none in the controls. Interpretation The high expression of GJ proteins Cx26, Cx30, and Cx43 in α-SMA positive myofibroblast-rich nodules, which are characteristic of the active involutional phase of DD, suggests that connexins could be a novel treatment target for the treatment of DD.
- Published
- 2014
141. 1个有汗性外胚层发育不良大家系的基因研究
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Male ,integumentary system ,Adolescent ,Ectodermal Dysplasia ,Mutation ,论著·临床研究 ,Connexin 30 ,Humans ,Female ,Connexins - Abstract
OBJECTIVE: To investigate the clinical features and molecular mechanism of hidrotic ectodermal dysplasia (HED). METHODS: A clinical and gene study was performed for five generations (91 people) in the family of one proband with HED. GJB6 gene detection was performed for 7 patients and 3 normal people in this family. RESULTS: Among the 91 people in this family, there were 17 HED patients, who were manifested as having dysplasia of the fingernails and toenails and sparse or absent hair or body hair. The male patients had a greater degree of sparse hair compared with female patients. In the younger generations, damage to the fingernails and toenails was gradually alleviated. There were patients in each generation, the patient's mother or father definitely had this disease. Both males and females developed this disease, and the inheritance pattern was autosomal dominant inheritance. A heterozygous missense mutation, 31G→A, in GJB6 gene was detected in all patients in this family, but this mutation was not detected in family members without the clinical manifestations of HED. CONCLUSIONS: HED is a hereditary disease with autosomal dominant inheritance and has the clinical features of dysplasia of the fingernails and toenails, hyperkeratosis of palms and soles, and sparse or absent hair or body hair. Male patients have a greater degree of sparse hair. In the younger generations, damage to the fingernails and toenails is gradually alleviated. The missense mutation 31G→A in the GJB6 gene may be one of the molecular mechanisms for HED.
- Published
- 2016
142. Hypothalamic Astroglial Connexins are Required for Brain Glucose Sensing-Induced Insulin Secretion
- Author
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Xavier Fioramonti, Brandon H. Cline, Chloé Chrétien, Christian Giaume, Fawzia Baba-Aissa, Luc Pénicaud, Sylvie Grall, Lionel Carneiro, Camille Allard, Corinne Leloup, Centre des Sciences du Goût et de l'Alimentation [Dijon] (CSGA), Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Centre interdisciplinaire de recherche en biologie (CIRB), Labex MemoLife, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Collège de France (CdF (institution))-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Collège de France (CdF), Centre des Sciences du Goût et de l'Alimentation [Dijon] ( CSGA ), Institut National de la Recherche Agronomique ( INRA ) -Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), and Collège de France ( CdF )
- Subjects
Male ,INVOLVEMENT ,HOMEOSTASIS ,medicine.medical_specialty ,medicine.medical_treatment ,Nerve Tissue Proteins ,Carbohydrate metabolism ,Biology ,ASTROCYTES ,Connexins ,connexin 43 ,RATS ,astrocyte ,Internal medicine ,Insulin Secretion ,medicine ,Animals ,Insulin ,TANYCYTES ,Rats, Wistar ,hypothalamus ,IN-VIVO ,HEMICHANNELS ,glucose sensing ,ARCUATE NUCLEUS ,Gap junction ,Fasting ,[ SDV.MHEP.EM ] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,BARRIER ,connexin 30 ,NETWORKS ,Glucose ,Endocrinology ,medicine.anatomical_structure ,Neurology ,Hypothalamus ,[ SDV.NEU ] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,RNA Interference ,Original Article ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,sense organs ,Neurology (clinical) ,Cardiology and Cardiovascular Medicine ,Thermogenesis ,Intracellular ,Homeostasis ,Astrocyte - Abstract
Supplementary Information accompanies the paper on the Journal of Cerebral Blood Flow & Metabolism website; Hypothalamic glucose detection participates in maintaining glycemic balance, food intake, and thermogenesis. Although hypothalamic neurons are the executive cells involved in these responses, there is increasing evidence that astrocytes participate in glucose sensing (GS); however, it is unknown whether astroglial networking is required for glucose sensitivity. Astroglial connexins 30 and 43 (Cx30 and Cx43) form hexameric channels, which are apposed in gap junctions, allowing for the intercellular transfer of small molecules such as glucose throughout the astroglial networks. Here, we hypothesized that hypothalamic glucose sensitivity requires these connexins. First, we showed that both Cxs are enriched in the rat hypothalamus, with highly concentrated Cx43 expression around blood vessels of the mediobasal hypothalamus (MBH). Both fasting and high glycemic levels rapidly altered the protein levels of MBH astroglial connexins, suggesting cross talk within the MBH between glycemic status and the connexins' ability to dispatch glucose. Finally, the inhibition of MBH Cx43 (by transient RNA interference) attenuated hypothalamic glucose sensitivity in rats, which was demonstrated by a pronounced decreased insulin secretion in response to a brain glucose challenge. These results illustrate that astroglial connexins contribute to hypothalamic GS.
- Published
- 2013
143. A Novel Connexin 30 Mutation in Clouston Syndrome.
- Author
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Smith, Frances J. D, Morley, Susan M, and McLean, W. H. Irwin
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- *
ECTODERMAL dysplasia , *GENETIC mutation - Abstract
Clouston syndrome (hidrotic ectodermal dysplasia) is an autosomal dominant ectodermal dysplasia characterized by alopecia, palmoplantar hyperkeratosis, and nail dystrophy. Recently, mutations in the GJB6 gene encoding the gap junction protein connexin 30 have been shown to cause this disorder. To date, all mutations have involved two codons: G11R and A88V. Here, we report a novel mutation V37E within the first transmembrane domain of connexin 30 in a spontaneous case of Clouston syndrome. The mutation was detected in genomic DNA, confirmed in reverse transcription polymerase chain reaction products, and was excluded from 100 ethnically matched control individuals by restriction enzyme analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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144. Screening of GJB6 Gene Large Deletions Among Syrians with Congenital Hearing Impairment
- Author
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Wafa Habbal, Tarek Zaidieh, and Fawza Monem
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Adult ,Male ,Proband ,Adolescent ,Hearing loss ,Hearing Loss, Sensorineural ,Genetic counseling ,Population ,Polymerase Chain Reaction ,Connexins ,Young Adult ,Gene Frequency ,Connexin 30 ,otorhinolaryngologic diseases ,medicine ,Humans ,Genetic Testing ,education ,Allele frequency ,Genetics (clinical) ,Sequence Deletion ,Genetic testing ,Genetics ,education.field_of_study ,Syria ,medicine.diagnostic_test ,biology ,business.industry ,Exons ,General Medicine ,Middle Aged ,Connexin 26 ,Case-Control Studies ,Mutation (genetic algorithm) ,biology.protein ,Female ,medicine.symptom ,business ,GJB6 - Abstract
Background: Research into the genetics of congenital hearing impairment in the Syrian population, where cases are noticeably encountered, is still in its infancy. Aims: Our goal was to estimate the frequencies of the del(GJB6-D13S1830) and del(GJB6-D13S1854) mutations in a group of Syrians with autosomal recessive nonsyndromic hearing loss (ARNSHL). Methods: Forty-one unrelated Syrian probands, already screened for exon 2, GJB2 gene mutations, were reanalyzed for del(GJB6-D13S1830) and del(GJB6-D13S1854) mutations by polymerase chain reaction. Results: The del(GJB6-D13S1830) mutation was only found in homozygosity in 1 of 41 probands (2.43%), while the del(GJB6-D13S1854) mutation was not detected in any of the enrolled patients. Coexistence of GJB2 and GJB6 mutations was not encountered in any case. Conclusions: Our study reports the first case in Syria with the del(GJB6-D13S1830) mutation. This mutation might be considered in the diagnosis and genetic counseling of inherited hearing impairment in the Syr...
- Published
- 2015
145. Mutations inGJB6causing phenotype resembling pachyonychia congenita
- Author
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G. Wylie, M. Zamiri, G.I. Hale, Mary E. Schwartz, Fjd Smith, and Neil J. Wilson
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Adult ,Male ,Adolescent ,Mutation, Missense ,Dermatology ,Biology ,Connexins ,Diagnosis, Differential ,Young Adult ,Ectodermal Dysplasia ,Connexin 30 ,medicine ,Humans ,Pachyonychia congenita ,Child ,Aged ,Genetics ,Middle Aged ,medicine.disease ,Phenotype ,Pachyonychia Congenita ,Mutation (genetic algorithm) ,biology.protein ,Female ,GJB6 - Published
- 2015
146. Mutant Cx30-A88V mice exhibit hydrocephaly and sex-dependent behavioral abnormalities, implicating a functional role for Cx30 in the brain.
- Author
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Novielli-Kuntz NM, Press ER, Barr K, Prado MAM, and Laird DW
- Subjects
- Animals, Astrocytes metabolism, Behavior, Animal, Brain pathology, Disease Models, Animal, Female, Gap Junctions genetics, Homozygote, Male, Maze Learning, Mice, Mice, Mutant Strains, Neuroglia metabolism, Sex Factors, Brain metabolism, Connexin 30 genetics, Connexin 43 genetics, Hydrocephalus genetics, Mutation
- Abstract
Connexin 30 (Cx30; also known as Gjb6 when referring to the mouse gene) is expressed in ependymal cells of the brain ventricles, in leptomeningeal cells and in astrocytes rich in connexin 43 (Cx43), leading us to question whether patients harboring GJB6 mutations exhibit any brain anomalies. Here, we used mice harboring the human disease-associated A88V Cx30 mutation to address this gap in knowledge. Brain Cx30 levels were lower in male and female Cx30
A88V/A88V mice compared with Cx30A88V/+ and Cx30+/+ mice, whereas Cx43 levels were lower only in female Cx30 mutant mice. Characterization of brain morphology revealed a disrupted ependymal cell layer, significant hydrocephalus and enlarged ventricles in 3- to 6-month-old adult male and female Cx30A88V/A88V mice compared with Cx30A88V/+ or Cx30+/+ sex-matched littermate mice. To determine the functional significance of these molecular and morphological changes, we investigated a number of behavioral activities in these mice. Interestingly, only female Cx30A88V/A88V mice exhibited abnormal behavior compared with all other groups. Cx30A88V/A88V female mice demonstrated increased locomotor and exploratory activity in both the open field and the elevated plus maze. They also exhibited dramatically reduced ability to learn the location of the escape platform during Morris water maze training, although they were able to swim as well as other genotypes. Our findings suggest that the homozygous A88V mutation in Cx30 causes major morphological changes in the brain of aging mice, possibly attributable to an abnormal ependymal cell layer. Remarkably, these changes had a more pronounced consequence for cognitive function in female mice, which is likely to be linked to the dysregulation of both Cx30 and Cx43 levels in the brain., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)- Published
- 2021
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147. Identification of four novel connexin 26 mutations in non-syndromic deaf patients: genotype–phenotype analysis in moderate cases
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Patricio O. Craig, Viviana Karina Dalamon, Raúl Reynoso Diamante, Enrique Mansilla, Ana Belén Elgoyhen, María E. Barteik, Bibiana Paoli, Vanesa Lotersztein, M. Florencia Wernert, and Carlos Curet
- Subjects
Models, Molecular ,Hearing loss ,DNA Mutational Analysis ,Molecular Sequence Data ,Connexin ,Deafness ,Connexins ,Genotype phenotype ,Ciencias Biológicas ,HEARING LOSS ,Genética y Herencia ,Audiometry ,GJB6 ,Connexin 30 ,Genetics ,medicine ,Humans ,Amino Acid Sequence ,Molecular Biology ,Alleles ,Genetic Association Studies ,DFNB1 ,biology ,General Medicine ,GJB2 ,Connexin 26 ,Mutation ,biology.protein ,Identification (biology) ,medicine.symptom ,Gene Deletion ,CIENCIAS NATURALES Y EXACTAS ,Non syndromic - Abstract
This paper presents a mutation as well as a genotype-phenotype analysis of the GJB2 and GJB6 genes in 476 samples from non-syndromic unrelated Argentinean deaf patients (104 familial and 372 sporadic cases). Most of them were of prelingual onset (82 %) and 27 % were cochlear implanted. Variation of sequences was detected in 171 of the 474 patients (36 %). Overall, 43 different sequence variations were identified in GJB2 and GJB6. Four of them are reported for the first time in GJB2: c.233dupG, p.Ala78Ser, p.Val190Asp and p.Cys211Tyr. Mutations in GJB6 were detected in 3 % of patients [nine del(GJB6-D13S1830) and three del(GJB6-D13S1854)]. Of the 43 different variations identified in GJB2, 6 were polymorphisms and of the others, 10 (27 %) were truncating and 27 (73 %) were nontruncating. Patients with two truncating mutations had significantly worse hearing impairment than all other groups. Moderate phenotypes were observed in a group of patients carrying biallelic mutations (23 %). This work shows the high prevalence of GJB2 mutations in the Argentinean population and presents an analysis of moderate phenotypes in our cohort. Fil: Dalamon, Viviana Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentina Fil: Wernert, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentina Fil: Lotersztein, Vanesa. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina Fil: Craig, Patricio Oliver. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; Argentina Fil: Reynoso, Raúl Alfredo. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Medicina. Centro Piloto de Deteccion de Errores Metabólicos; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Centro Otoaudiológico de Alta Tecnología; Argentina Fil: Barteik, María Eugenia. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Medicina. Centro Piloto de Deteccion de Errores Metabólicos; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Centro Otoaudiológico de Alta Tecnología; Argentina Fil: Curet, Carlos Augusto. Universidad Nacional de Córdoba. Facultad de Medicina. Departamento de Medicina. Centro Piloto de Deteccion de Errores Metabólicos; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Centro Otoaudiológico de Alta Tecnología; Argentina Fil: Paoli, Bibiana. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina Fil: Mansilla, Enrique. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina Fil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Farmacología; Argentina
- Published
- 2013
148. Mouse Otocyst Transuterine Gene Transfer Restores Hearing in Mice With Connexin 30 Deletion-associated Hearing Loss
- Author
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Toru Miwa, Takao Yamada, Momoko Ise, Ryosei Minoda, and Eiji Yumoto
- Subjects
Hearing loss ,Transgene ,Blotting, Western ,Connexin ,Mice, Inbred Strains ,Mice, Transgenic ,Biology ,medicine.disease_cause ,Congenital hearing loss ,Connexins ,Small hairpin RNA ,Mice ,Hearing ,Drug Discovery ,medicine ,Connexin 30 ,otorhinolaryngologic diseases ,Genetics ,Animals ,RNA, Small Interfering ,Hearing Loss ,Gene ,Molecular Biology ,Cochlea ,Pharmacology ,Mutation ,Gene Transfer Techniques ,Genetic Therapy ,Molecular biology ,Immunohistochemistry ,Cell biology ,Molecular Medicine ,Original Article ,medicine.symptom ,Gene Deletion ,Plasmids - Abstract
Although numerous causative genes for hereditary hearing loss have been identified, there are no fundamental treatments for this condition. Herein, we describe a novel potential treatment for genetic hearing loss. Because mutations or deletions in the connexin (Cx) genes are common causes of profound congenital hearing loss in both humans and mice, we investigated whether gene supplementation therapy using the wild-type Cx gene could cure hearing loss. We first generated inner ear-specific connexin 30 (Cx30)-deficient mice via the transuterine transfer of Cx30-targeted short hairpin RNA (shRNA-Cx30) into otocysts. The inner ear-specific Cx30-deficient mice mimicked homozygous Cx30-deficient mice both histologically and physiologically. Subsequently, we cotransfected the shRNA-Cx30 and the wild-type Cx30 gene. The cotransfected mice exhibited Cx30 expression in the cochleae and displayed normal auditory functions. Next, we performed the transuterine transfer of the wild-type Cx30 gene into the otocysts of homozygous Cx30-deficient mice, thereby rescuing the lack of Cx30 expression in the cochleae and restoring auditory functioning. These results demonstrate that supplementation therapy with wild-type genes can restore postnatal auditory functioning. Moreover, this is the first report to show that Cx-related genetic hearing loss is treatable by in vivo gene therapy.
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- 2013
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149. Astrocytic Cx43 and Cx30 differentially modulate adult neurogenesis in mice
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Otto W. Witte, Christiane Frahm, Marie Liebmann, Madlen Guenther, and Anna Stahr
- Subjects
Doublecortin Protein ,Cell Survival ,Neurogenesis ,Cellular differentiation ,Connexin ,Mice, Transgenic ,Connexins ,Subgranular zone ,Mice ,Connexin 30 ,medicine ,Animals ,Mice, Knockout ,Neurons ,biology ,General Neuroscience ,Dentate gyrus ,Cell Differentiation ,Doublecortin ,Cell biology ,medicine.anatomical_structure ,Animals, Newborn ,nervous system ,Astrocytes ,Connexin 43 ,biology.protein ,sense organs ,NeuN ,Neuroscience ,Astrocyte - Abstract
In addition to their well known function in astrocyte coupling, gap junction forming connexins are also important for cell proliferation, migration and differentiation during brain development. The aim of this study was to determine whether loss of the main astrocytic connexins, connexin 43 (Cx43) or connexin 30 (Cx30), influences various stages of adult hippocampal neurogenesis. To that end, mice with a conditional Cx43 deletion in astrocytes and mice with a conventional knockout of Cx30 were used. We assessed cell proliferation based on Ki67-immunoreactive cell number and cell survival based on BrdU-immunoreactive cell number in the subgranular zone (SGZ) and the granular cell layer (GCL) of the dentate gyrus. The neuronal phenotype of surviving cells was analyzed following immunofluorescent co-localization of BrdU-positive cells with the neuronal markers doublecortin (DCX) and neuronal nuclear antigen (NeuN). Ablation of Cx43 in astrocytes significantly diminished proliferation and reduced the overall survival of newborn cells. In contrast, knockout of Cx30 showed a tendency towards increased proliferation and significantly enhanced the overall survival of newborn cells. The differentiation of surviving cells into neurons is unaffected following Cx43 or Cx30 knockout. Our data reveal that Cx43 promotes the survival of newborn neurons in the adult mouse hippocampus whereas Cx30 restricts their survival.
- Published
- 2013
150. Prevalence of DFNB1 mutations among cochlear implant users in Slovakia and its clinical implications
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Iwar Klimes, Zuzana Kabátová, Milan Profant, Ivica Masindova, Daniela Gasperikova, M Huckova, and Lukas Varga
- Subjects
Male ,Slovakia ,Genotype ,medicine.medical_treatment ,Population ,Locus (genetics) ,Deafness ,Connexins ,White People ,Cochlear implant ,Connexin 30 ,otorhinolaryngologic diseases ,Humans ,Medicine ,Missense mutation ,Allele ,education ,Genetics ,education.field_of_study ,biology ,business.industry ,General Medicine ,Cochlear Implantation ,Connexin 26 ,Otorhinolaryngology ,Mutation ,biology.protein ,Etiology ,Female ,business ,GJB6 - Abstract
Hereditary etiology plays an important role in bilateral profound deafness as a main indication for cochlear implantation. Mutations in DFNB1 locus account for most of the inherited deafness cases in Caucasians. To provide actual data on mutation prevalence among implanted deaf subpopulation, we performed DNA analysis of GJB2 and GJB6 genes in 131 unrelated Slovak cochlear implant users. Eight previously described causal mutations and one probably pathogenic missense variant (c.127G>A) were detected in the GJB2 gene in 58 (44.28 %) subjects. The most common mutation found was c.35delG with frequency 83.02 % of all disease alleles, followed by c.71G>A, c.1-3201G>A, c.313_326del14, c.109G>A, 167delT, c.269T>C, and c.333_334delAA. GJB6 deletion delD13S1830 was identified in only one subject, in double heterozygosity with a GJB6 mutation. Thus, the deafness cause could be clearly attributable to DFNB1 mutations in 36.64 % of the patients examined. In summary, the mutation profile found in our cohort was similar to the mutation spectrum reported for Central European deaf populations. The mutation prevalence in cochlear implant users was, however, almost by 25 % higher than previously established for non-implanted hearing-impaired population in Slovakia. Finally, we also demonstrate a certain variability in deafness onset in patients with causal genotype and coincidence with other risk factors for deafness. Our results underline the importance of genetic tests in all cochlear implant candidates.
- Published
- 2013
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