Developmental patterns of DR6 in normal human hippocampus and in Down syndrome / A. IYER in Journal of Neurodevelopmental Disorders, 5-1 (December 2013)  

Public ISBD [article]  inJournal of Neurodevelopmental Disorders > 5-1 (December 2013) . - p.10 Titre : Developmental patterns of DR6 in normal human hippocampus and in Down syndrome Type de document : Texte imprimé et/ou numérique Auteurs : A. IYER, Auteur ; J. VAN SCHEPPINGEN, Auteur ; J. ANINK, Auteur ; I. MILENKOVIC, Auteur ; G. G. KOVACS, Auteur ; E. ARONICA, Auteur Article en page(s) : p.10 Langues : Anglais (eng) Index. décimale : PER Périodiques Résumé : BACKGROUND: Death receptor 6 (DR6) is highly expressed in the human brain: it has been shown to induce axon pruning and neuron death via distinct caspases and to mediate axonal degeneration through binding to N-terminal beta amyloid precursor protein (N-APP). METHODS: We investigated the expression of DR6 during prenatal and postnatal development in human hippocampus and temporal cortex by immunocytochemistry and Western blot analysis (118 normal human brain specimens; 9 to 41 gestational weeks; 1 day to 7 months postnatally; 3 to 91 years). To investigate the role of N-APP/DR6/caspase 6 pathway in the development of hippocampal Alzheimer's disease (AD)-associated pathology, we examined DR6 immunoreactivity (IR) in the developing hippocampus from patients with Down syndrome (DS; 48 brain specimens; 14 to 41 gestational weeks; 7 days to 8 months postnatally; 15 to 64 years) and in adults with DS and AD. RESULTS: DR6 was highly expressed in human adult hippocampus and temporal cortex: we observed consistent similar temporal and spatial expression in both control and DS brain. Western blot analysis of total homogenates of temporal cortex and hippocampus showed developmental regulation of DR6. In the hippocampus, DR6 IR was first apparent in the stratum lacunosum-moleculare at 16 weeks of gestation, followed by stratum oriens, radiatum, pyramidale (CA1 to CA4) and molecular layer of the dentate gyrus between 21 and 23 gestational weeks, reaching a pattern similar to adult hippocampus around birth. Increased DR6 expression in dystrophic neurites was detected focally in a 15-year-old DS patient. Abnormal DR6 expression pattern, with increased expression within dystrophic neurites in and around amyloid plaques was observed in adult DS patients with widespread AD-associated neurodegeneration and was similar to the pattern observed in AD hippocampus. Double-labeling experiments demonstrated the colocalization, in dystrophic neurites, of DR6 with APP. We also observed colocalization with hyper-phosphorylated Tau and with caspase 6 (increased in hippocampus with AD pathology) in plaque-associated dystrophic neurites and within the white matter. CONCLUSIONS: These findings demonstrate a developmental regulation of DR6 in human hippocampus and suggest an abnormal activation of the N-APP/DR6/caspase 6 pathway, which can contribute to initiation or progression of hippocampal AD-associated pathology. En ligne : http://dx.doi.org/10.1186/1866-1955-5-10 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345 [article] Developmental patterns of DR6 in normal human hippocampus and in Down syndrome [Texte imprimé et/ou numérique] / A. IYER, Auteur ; J. VAN SCHEPPINGEN, Auteur ; J. ANINK, Auteur ; I. MILENKOVIC, Auteur ; G. G. KOVACS, Auteur ; E. ARONICA, Auteur . - p.10. Langues : Anglais (eng) in Journal of Neurodevelopmental Disorders > 5-1 (December 2013) . - p.10 Index. décimale : PER Périodiques Résumé : BACKGROUND: Death receptor 6 (DR6) is highly expressed in the human brain: it has been shown to induce axon pruning and neuron death via distinct caspases and to mediate axonal degeneration through binding to N-terminal beta amyloid precursor protein (N-APP). METHODS: We investigated the expression of DR6 during prenatal and postnatal development in human hippocampus and temporal cortex by immunocytochemistry and Western blot analysis (118 normal human brain specimens; 9 to 41 gestational weeks; 1 day to 7 months postnatally; 3 to 91 years). To investigate the role of N-APP/DR6/caspase 6 pathway in the development of hippocampal Alzheimer's disease (AD)-associated pathology, we examined DR6 immunoreactivity (IR) in the developing hippocampus from patients with Down syndrome (DS; 48 brain specimens; 14 to 41 gestational weeks; 7 days to 8 months postnatally; 15 to 64 years) and in adults with DS and AD. RESULTS: DR6 was highly expressed in human adult hippocampus and temporal cortex: we observed consistent similar temporal and spatial expression in both control and DS brain. Western blot analysis of total homogenates of temporal cortex and hippocampus showed developmental regulation of DR6. In the hippocampus, DR6 IR was first apparent in the stratum lacunosum-moleculare at 16 weeks of gestation, followed by stratum oriens, radiatum, pyramidale (CA1 to CA4) and molecular layer of the dentate gyrus between 21 and 23 gestational weeks, reaching a pattern similar to adult hippocampus around birth. Increased DR6 expression in dystrophic neurites was detected focally in a 15-year-old DS patient. Abnormal DR6 expression pattern, with increased expression within dystrophic neurites in and around amyloid plaques was observed in adult DS patients with widespread AD-associated neurodegeneration and was similar to the pattern observed in AD hippocampus. Double-labeling experiments demonstrated the colocalization, in dystrophic neurites, of DR6 with APP. We also observed colocalization with hyper-phosphorylated Tau and with caspase 6 (increased in hippocampus with AD pathology) in plaque-associated dystrophic neurites and within the white matter. CONCLUSIONS: These findings demonstrate a developmental regulation of DR6 in human hippocampus and suggest an abnormal activation of the N-APP/DR6/caspase 6 pathway, which can contribute to initiation or progression of hippocampal AD-associated pathology. En ligne : http://dx.doi.org/10.1186/1866-1955-5-10 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345

Role of miR-146a in neural stem cell differentiation and neural lineage determination: relevance for neurodevelopmental disorders / L. S. NGUYEN in Molecular Autism, 9 (2018)  

Public ISBD [article]  inMolecular Autism > 9 (2018) . - 38p. Titre : Role of miR-146a in neural stem cell differentiation and neural lineage determination: relevance for neurodevelopmental disorders Type de document : Texte imprimé et/ou numérique Auteurs : L. S. NGUYEN, Auteur ; J. FREGEAC, Auteur ; C. BOLE-FEYSOT, Auteur ; N. CAGNARD, Auteur ; A. IYER, Auteur ; J. ANINK, Auteur ; E. ARONICA, Auteur ; O. ALIBEU, Auteur ; P. NITSCHKE, Auteur ; L. COLLEAUX, Auteur Article en page(s) : 38p. Langues : Anglais (eng) Mots-clés : Autism Spectrum Disorder/genetics/metabolism  Cell Line  Cell Lineage  Child  Female  Humans  Male  MicroRNAs/genetics/metabolism  Neural Stem Cells/cytology/metabolism  Neurogenesis  Temporal Lobe/cytology/metabolism  Up-Regulation  Autism spectrum disorders  Human neural stem cell  Transcriptome  microRNA Index. décimale : PER Périodiques Résumé : Background: MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. miRNAs have emerged as important modulators of brain development and neuronal function and are implicated in several neurological diseases. Previous studies found miR-146a upregulation is the most common miRNA deregulation event in neurodevelopmental disorders such as autism spectrum disorder (ASD), epilepsy, and intellectual disability (ID). Yet, how miR-146a upregulation affects the developing fetal brain remains unclear. Methods: We analyzed the expression of miR-146a in the temporal lobe of ASD children using Taqman assay. To assess the role of miR-146a in early brain development, we generated and characterized stably induced H9 human neural stem cell (H9 hNSC) overexpressing miR-146a using various cell and molecular biology techniques. Results: We first showed that miR-146a upregulation occurs early during childhood in the ASD brain. In H9 hNSC, miR-146a overexpression enhances neurite outgrowth and branching and favors differentiation into neuronal like cells. Expression analyses revealed that 10% of the transcriptome was deregulated and organized into two modules critical for cell cycle control and neuronal differentiation. Twenty known or predicted targets of miR-146a were significantly deregulated in the modules, acting as potential drivers. The two modules also display distinct transcription profiles during human brain development, affecting regions relevant for ASD including the neocortex, amygdala, and hippocampus. Cell type analyses indicate markers for pyramidal, and interneurons are highly enriched in the deregulated gene list. Up to 40% of known markers of newly defined neuronal lineages were deregulated, suggesting that miR-146a could participate also in the acquisition of neuronal identities. Conclusion: Our results demonstrate the dynamic roles of miR-146a in early neuronal development and provide new insight into the molecular events that link miR-146a overexpression to impaired neurodevelopment. This, in turn, may yield new therapeutic targets and strategies. En ligne : https://dx.doi.org/10.1186/s13229-018-0219-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=371 [article] Role of miR-146a in neural stem cell differentiation and neural lineage determination: relevance for neurodevelopmental disorders [Texte imprimé et/ou numérique] / L. S. NGUYEN, Auteur ; J. FREGEAC, Auteur ; C. BOLE-FEYSOT, Auteur ; N. CAGNARD, Auteur ; A. IYER, Auteur ; J. ANINK, Auteur ; E. ARONICA, Auteur ; O. ALIBEU, Auteur ; P. NITSCHKE, Auteur ; L. COLLEAUX, Auteur . - 38p. Langues : Anglais (eng) in Molecular Autism > 9 (2018) . - 38p. Mots-clés : Autism Spectrum Disorder/genetics/metabolism  Cell Line  Cell Lineage  Child  Female  Humans  Male  MicroRNAs/genetics/metabolism  Neural Stem Cells/cytology/metabolism  Neurogenesis  Temporal Lobe/cytology/metabolism  Up-Regulation  Autism spectrum disorders  Human neural stem cell  Transcriptome  microRNA Index. décimale : PER Périodiques Résumé : Background: MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. miRNAs have emerged as important modulators of brain development and neuronal function and are implicated in several neurological diseases. Previous studies found miR-146a upregulation is the most common miRNA deregulation event in neurodevelopmental disorders such as autism spectrum disorder (ASD), epilepsy, and intellectual disability (ID). Yet, how miR-146a upregulation affects the developing fetal brain remains unclear. Methods: We analyzed the expression of miR-146a in the temporal lobe of ASD children using Taqman assay. To assess the role of miR-146a in early brain development, we generated and characterized stably induced H9 human neural stem cell (H9 hNSC) overexpressing miR-146a using various cell and molecular biology techniques. Results: We first showed that miR-146a upregulation occurs early during childhood in the ASD brain. In H9 hNSC, miR-146a overexpression enhances neurite outgrowth and branching and favors differentiation into neuronal like cells. Expression analyses revealed that 10% of the transcriptome was deregulated and organized into two modules critical for cell cycle control and neuronal differentiation. Twenty known or predicted targets of miR-146a were significantly deregulated in the modules, acting as potential drivers. The two modules also display distinct transcription profiles during human brain development, affecting regions relevant for ASD including the neocortex, amygdala, and hippocampus. Cell type analyses indicate markers for pyramidal, and interneurons are highly enriched in the deregulated gene list. Up to 40% of known markers of newly defined neuronal lineages were deregulated, suggesting that miR-146a could participate also in the acquisition of neuronal identities. Conclusion: Our results demonstrate the dynamic roles of miR-146a in early neuronal development and provide new insight into the molecular events that link miR-146a overexpression to impaired neurodevelopment. This, in turn, may yield new therapeutic targets and strategies. En ligne : https://dx.doi.org/10.1186/s13229-018-0219-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=371

Specific pattern of maturation and differentiation in the formation of cortical tubers in tuberous sclerosis omplex (TSC): evidence from layer-specific marker expression / A. MUHLEBNER in Journal of Neurodevelopmental Disorders, 8-1 (December 2016)  

Public ISBD [article]  inJournal of Neurodevelopmental Disorders > 8-1 (December 2016) . - p.9 Titre : Specific pattern of maturation and differentiation in the formation of cortical tubers in tuberous sclerosis omplex (TSC): evidence from layer-specific marker expression Type de document : Texte imprimé et/ou numérique Auteurs : A. MUHLEBNER, Auteur ; A. M. IYER, Auteur ; J. VAN SCHEPPINGEN, Auteur ; J. ANINK, Auteur ; F. E. JANSEN, Auteur ; T. J. VEERSEMA, Auteur ; K. P. BRAUN, Auteur ; W. G. SPLIET, Auteur ; W. VAN HECKE, Auteur ; F. SOYLEMEZOGLU, Auteur ; M. FEUCHT, Auteur ; P. KRSEK, Auteur ; J. ZAMECNIK, Auteur ; C. G. BIEN, Auteur ; T. POLSTER, Auteur ; R. CORAS, Auteur ; I. BLUMCKE, Auteur ; E. ARONICA, Auteur Article en page(s) : p.9 Langues : Anglais (eng) Mots-clés : Cortical layer markers  Epilepsy  Neuropathology  Neurosurgery  Tuberous sclerosis complex Index. décimale : PER Périodiques Résumé : BACKGROUND: Tuberous sclerosis complex (TSC) is a multisystem disorder that results from mutations in the TSC1 or TSC2 genes, leading to constitutive activation of the mammalian target of rapamycin (mTOR) signaling pathway. Cortical tubers represent typical lesions of the central nervous system (CNS) in TSC. The pattern of cortical layering disruption observed in brain tissue of TSC patients is not yet fully understood, and little is known about the origin and phenotype of individual abnormal cell types recognized in tubers. METHODS: In the present study, we aimed to characterize dysmorphic neurons (DNs) and giant cells (GCs) of cortical tubers using neocortical layer-specific markers (NeuN, SMI32, Tbr1, Satb2, Cux2, ER81, and RORbeta) and to compare the features with the histo-morphologically similar focal cortical dysplasia (FCD) type IIb. We studied a cohort of nine surgically resected cortical tubers, five FCD type IIb, and four control samples using immunohistochemistry and in situ hybridization. RESULTS: Cortical tuber displayed a prominent cell loss in all cortical layers. Moreover, we observed altered proportions of layer-specific markers within the dysplastic region. DNs, in both tubers and FCD type IIb, were found positive for different cortical layer markers, regardless of their laminar location, and their immunophenotype resembles that of cortical projection neurons. CONCLUSIONS: These findings demonstrate that, similar to FCD type IIb, cortical layering is markedly disturbed in cortical tubers of TSC patients. Distribution of these disturbances is comparable in all tubers and suggests a dysmaturation affecting early and late migratory patterns, with a more severe impairment of the late stage of maturation. En ligne : http://dx.doi.org/10.1186/s11689-016-9142-0 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=348 [article] Specific pattern of maturation and differentiation in the formation of cortical tubers in tuberous sclerosis omplex (TSC): evidence from layer-specific marker expression [Texte imprimé et/ou numérique] / A. MUHLEBNER, Auteur ; A. M. IYER, Auteur ; J. VAN SCHEPPINGEN, Auteur ; J. ANINK, Auteur ; F. E. JANSEN, Auteur ; T. J. VEERSEMA, Auteur ; K. P. BRAUN, Auteur ; W. G. SPLIET, Auteur ; W. VAN HECKE, Auteur ; F. SOYLEMEZOGLU, Auteur ; M. FEUCHT, Auteur ; P. KRSEK, Auteur ; J. ZAMECNIK, Auteur ; C. G. BIEN, Auteur ; T. POLSTER, Auteur ; R. CORAS, Auteur ; I. BLUMCKE, Auteur ; E. ARONICA, Auteur . - p.9. Langues : Anglais (eng) in Journal of Neurodevelopmental Disorders > 8-1 (December 2016) . - p.9 Mots-clés : Cortical layer markers  Epilepsy  Neuropathology  Neurosurgery  Tuberous sclerosis complex Index. décimale : PER Périodiques Résumé : BACKGROUND: Tuberous sclerosis complex (TSC) is a multisystem disorder that results from mutations in the TSC1 or TSC2 genes, leading to constitutive activation of the mammalian target of rapamycin (mTOR) signaling pathway. Cortical tubers represent typical lesions of the central nervous system (CNS) in TSC. The pattern of cortical layering disruption observed in brain tissue of TSC patients is not yet fully understood, and little is known about the origin and phenotype of individual abnormal cell types recognized in tubers. METHODS: In the present study, we aimed to characterize dysmorphic neurons (DNs) and giant cells (GCs) of cortical tubers using neocortical layer-specific markers (NeuN, SMI32, Tbr1, Satb2, Cux2, ER81, and RORbeta) and to compare the features with the histo-morphologically similar focal cortical dysplasia (FCD) type IIb. We studied a cohort of nine surgically resected cortical tubers, five FCD type IIb, and four control samples using immunohistochemistry and in situ hybridization. RESULTS: Cortical tuber displayed a prominent cell loss in all cortical layers. Moreover, we observed altered proportions of layer-specific markers within the dysplastic region. DNs, in both tubers and FCD type IIb, were found positive for different cortical layer markers, regardless of their laminar location, and their immunophenotype resembles that of cortical projection neurons. CONCLUSIONS: These findings demonstrate that, similar to FCD type IIb, cortical layering is markedly disturbed in cortical tubers of TSC patients. Distribution of these disturbances is comparable in all tubers and suggests a dysmaturation affecting early and late migratory patterns, with a more severe impairment of the late stage of maturation. En ligne : http://dx.doi.org/10.1186/s11689-016-9142-0 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=348

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