Copy number variants (CNVs): a powerful tool for iPSC-based modelling of ASD / Danijela DRAKULIC in Molecular Autism, 11 (2020)  

Public ISBD [article]  inMolecular Autism > 11 (2020) . - 42 p. Titre : Copy number variants (CNVs): a powerful tool for iPSC-based modelling of ASD Type de document : Texte imprimé et/ou numérique Auteurs : Danijela DRAKULIC, Auteur ; Srdjan DJUROVIC, Auteur ; Yasir Ahmed SYED, Auteur ; Sebastiano TRATTARO, Auteur ; Nicolò CAPORALE, Auteur ; Anna FALK, Auteur ; Rivka OFIR, Auteur ; Vivi M. HEINE, Auteur ; Samuel J. R. A. CHAWNER, Auteur ; Antonio RODRIGUEZ-MORENO, Auteur ; Marianne B. M. VAN DEN BREE, Auteur ; Giuseppe TESTA, Auteur ; Spyros PETRAKIS, Auteur ; Adrian J. HARWOOD, Auteur Article en page(s) : 42 p. Langues : Anglais (eng) Mots-clés : Autism spectrum disorders (ASD)  Copy number variants (CNVs)  Human iPSCs  Neurodevelopmental disorders (NDD) Index. décimale : PER Périodiques Résumé : Patients diagnosed with chromosome microdeletions or duplications, known as copy number variants (CNVs), present a unique opportunity to investigate the relationship between patient genotype and cell phenotype. CNVs have high genetic penetrance and give a good correlation between gene locus and patient clinical phenotype. This is especially effective for the study of patients with neurodevelopmental disorders (NDD), including those falling within the autism spectrum disorders (ASD). A key question is whether this correlation between genetics and clinical presentation at the level of the patient can be translated to the cell phenotypes arising from the neurodevelopment of patient induced pluripotent stem cells (iPSCs).Here, we examine how iPSCs derived from ASD patients with an associated CNV inform our understanding of the genetic and biological mechanisms underlying the aetiology of ASD. We consider selection of genetically characterised patient iPSCs; use of appropriate control lines; aspects of human neurocellular biology that can capture in vitro the patient clinical phenotype; and current limitations of patient iPSC-based studies. Finally, we consider how future research may be enhanced to maximise the utility of CNV patients for research of pathological mechanisms or therapeutic targets. En ligne : http://dx.doi.org/10.1186/s13229-020-00343-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=427 [article] Copy number variants (CNVs): a powerful tool for iPSC-based modelling of ASD [Texte imprimé et/ou numérique] / Danijela DRAKULIC, Auteur ; Srdjan DJUROVIC, Auteur ; Yasir Ahmed SYED, Auteur ; Sebastiano TRATTARO, Auteur ; Nicolò CAPORALE, Auteur ; Anna FALK, Auteur ; Rivka OFIR, Auteur ; Vivi M. HEINE, Auteur ; Samuel J. R. A. CHAWNER, Auteur ; Antonio RODRIGUEZ-MORENO, Auteur ; Marianne B. M. VAN DEN BREE, Auteur ; Giuseppe TESTA, Auteur ; Spyros PETRAKIS, Auteur ; Adrian J. HARWOOD, Auteur . - 42 p. Langues : Anglais (eng) in Molecular Autism > 11 (2020) . - 42 p. Mots-clés : Autism spectrum disorders (ASD)  Copy number variants (CNVs)  Human iPSCs  Neurodevelopmental disorders (NDD) Index. décimale : PER Périodiques Résumé : Patients diagnosed with chromosome microdeletions or duplications, known as copy number variants (CNVs), present a unique opportunity to investigate the relationship between patient genotype and cell phenotype. CNVs have high genetic penetrance and give a good correlation between gene locus and patient clinical phenotype. This is especially effective for the study of patients with neurodevelopmental disorders (NDD), including those falling within the autism spectrum disorders (ASD). A key question is whether this correlation between genetics and clinical presentation at the level of the patient can be translated to the cell phenotypes arising from the neurodevelopment of patient induced pluripotent stem cells (iPSCs).Here, we examine how iPSCs derived from ASD patients with an associated CNV inform our understanding of the genetic and biological mechanisms underlying the aetiology of ASD. We consider selection of genetically characterised patient iPSCs; use of appropriate control lines; aspects of human neurocellular biology that can capture in vitro the patient clinical phenotype; and current limitations of patient iPSC-based studies. Finally, we consider how future research may be enhanced to maximise the utility of CNV patients for research of pathological mechanisms or therapeutic targets. En ligne : http://dx.doi.org/10.1186/s13229-020-00343-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=427

Pharmacological intervention to restore connectivity deficits of neuronal networks derived from ASD patient iPSC with a TSC2 mutation / Mouhamed ALSAQATI in Molecular Autism, 11 (2020)  

Public ISBD [article]  inMolecular Autism > 11 (2020) . - 80 p. Titre : Pharmacological intervention to restore connectivity deficits of neuronal networks derived from ASD patient iPSC with a TSC2 mutation Type de document : Texte imprimé et/ou numérique Auteurs : Mouhamed ALSAQATI, Auteur ; Vivi M. HEINE, Auteur ; Adrian J. HARWOOD, Auteur Article en page(s) : 80 p. Langues : Anglais (eng) Index. décimale : PER Périodiques Résumé : BACKGROUND: Tuberous sclerosis complex (TSC) is a rare genetic multisystemic disorder resulting from autosomal dominant mutations in the TSC1 or TSC2 genes. It is characterised by hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway and has severe neurodevelopmental and neurological components including autism, intellectual disability and epilepsy. In human and rodent models, loss of the TSC proteins causes neuronal hyperexcitability and synaptic dysfunction, although the consequences of these changes for the developing central nervous system are currently unclear. METHODS: Here we apply multi-electrode array-based assays to study the effects of TSC2 loss on neuronal network activity using autism spectrum disorder (ASD) patient-derived iPSCs. We examine both temporal synchronisation of neuronal bursting and spatial connectivity between electrodes across the network. RESULTS: We find that ASD patient-derived neurons with a functional loss of TSC2, in addition to possessing neuronal hyperactivity, develop a dysfunctional neuronal network with reduced synchronisation of neuronal bursting and lower spatial connectivity. These deficits of network function are associated with elevated expression of genes for inhibitory GABA signalling and glutamate signalling, indicating a potential abnormality of synaptic inhibitory-excitatory signalling. mTORC1 activity functions within a homeostatic triad of protein kinases, mTOR, AMP-dependent protein Kinase 1 (AMPK) and Unc-51 like Autophagy Activating Kinase 1 (ULK1) that orchestrate the interplay of anabolic cell growth and catabolic autophagy while balancing energy and nutrient homeostasis. The mTOR inhibitor rapamycin suppresses neuronal hyperactivity, but does not increase synchronised network activity, whereas activation of AMPK restores some aspects of network activity. In contrast, the ULK1 activator, LYN-1604, increases the network behaviour, shortens the network burst lengths and reduces the number of uncorrelated spikes. LIMITATIONS: Although a robust and consistent phenotype is observed across multiple independent iPSC cultures, the results are based on one patient. There may be more subtle differences between patients with different TSC2 mutations or differences of polygenic background within their genomes. This may affect the severity of the network deficit or the pharmacological response between TSC2 patients. CONCLUSIONS: Our observations suggest that there is a reduction in the network connectivity of the in vitro neuronal network associated with ASD patients with TSC2 mutation, which may arise via an excitatory/inhibitory imbalance due to increased GABA-signalling at inhibitory synapses. This abnormality can be effectively suppressed via activation of ULK1. En ligne : http://dx.doi.org/10.1186/s13229-020-00391-w Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=433 [article] Pharmacological intervention to restore connectivity deficits of neuronal networks derived from ASD patient iPSC with a TSC2 mutation [Texte imprimé et/ou numérique] / Mouhamed ALSAQATI, Auteur ; Vivi M. HEINE, Auteur ; Adrian J. HARWOOD, Auteur . - 80 p. Langues : Anglais (eng) in Molecular Autism > 11 (2020) . - 80 p. Index. décimale : PER Périodiques Résumé : BACKGROUND: Tuberous sclerosis complex (TSC) is a rare genetic multisystemic disorder resulting from autosomal dominant mutations in the TSC1 or TSC2 genes. It is characterised by hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway and has severe neurodevelopmental and neurological components including autism, intellectual disability and epilepsy. In human and rodent models, loss of the TSC proteins causes neuronal hyperexcitability and synaptic dysfunction, although the consequences of these changes for the developing central nervous system are currently unclear. METHODS: Here we apply multi-electrode array-based assays to study the effects of TSC2 loss on neuronal network activity using autism spectrum disorder (ASD) patient-derived iPSCs. We examine both temporal synchronisation of neuronal bursting and spatial connectivity between electrodes across the network. RESULTS: We find that ASD patient-derived neurons with a functional loss of TSC2, in addition to possessing neuronal hyperactivity, develop a dysfunctional neuronal network with reduced synchronisation of neuronal bursting and lower spatial connectivity. These deficits of network function are associated with elevated expression of genes for inhibitory GABA signalling and glutamate signalling, indicating a potential abnormality of synaptic inhibitory-excitatory signalling. mTORC1 activity functions within a homeostatic triad of protein kinases, mTOR, AMP-dependent protein Kinase 1 (AMPK) and Unc-51 like Autophagy Activating Kinase 1 (ULK1) that orchestrate the interplay of anabolic cell growth and catabolic autophagy while balancing energy and nutrient homeostasis. The mTOR inhibitor rapamycin suppresses neuronal hyperactivity, but does not increase synchronised network activity, whereas activation of AMPK restores some aspects of network activity. In contrast, the ULK1 activator, LYN-1604, increases the network behaviour, shortens the network burst lengths and reduces the number of uncorrelated spikes. LIMITATIONS: Although a robust and consistent phenotype is observed across multiple independent iPSC cultures, the results are based on one patient. There may be more subtle differences between patients with different TSC2 mutations or differences of polygenic background within their genomes. This may affect the severity of the network deficit or the pharmacological response between TSC2 patients. CONCLUSIONS: Our observations suggest that there is a reduction in the network connectivity of the in vitro neuronal network associated with ASD patients with TSC2 mutation, which may arise via an excitatory/inhibitory imbalance due to increased GABA-signalling at inhibitory synapses. This abnormality can be effectively suppressed via activation of ULK1. En ligne : http://dx.doi.org/10.1186/s13229-020-00391-w Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=433

Quantitative proteomic analysis of Rett iPSC-derived neuronal progenitors / Suzy VARDERIDOU-MINASIAN in Molecular Autism, 11 (2020)  

Public ISBD [article]  inMolecular Autism > 11 (2020) . - 38 p. Titre : Quantitative proteomic analysis of Rett iPSC-derived neuronal progenitors Type de document : Texte imprimé et/ou numérique Auteurs : Suzy VARDERIDOU-MINASIAN, Auteur ; Lisa HINZ, Auteur ; Dominique HAGEMANS, Auteur ; Daniëlle POSTHUMA, Auteur ; Maarten ALTELAAR, Auteur ; Vivi M. HEINE, Auteur Article en page(s) : 38 p. Langues : Anglais (eng) Mots-clés : Neuron differentiation  Quantitative mass spectrometry  Rett syndrome  TMT-10plex  iPSC Index. décimale : PER Périodiques Résumé : BACKGROUND: Rett syndrome (RTT) is a progressive neurodevelopmental disease that is characterized by abnormalities in cognitive, social, and motor skills. RTT is often caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2). The mechanism by which impaired MeCP2 induces the pathological abnormalities in the brain is not understood. Both patients and mouse models have shown abnormalities at molecular and cellular level before typical RTT-associated symptoms appear. This implies that underlying mechanisms are already affected during neurodevelopmental stages. METHODS: To understand the molecular mechanisms involved in disease onset, we used an RTT patient induced pluripotent stem cell (iPSC)-based model with isogenic controls and performed time-series of proteomic analysis using in-depth high-resolution quantitative mass spectrometry during early stages of neuronal development. RESULTS: We provide mass spectrometry-based quantitative proteomic data, depth of about 7000 proteins, at neuronal progenitor developmental stages of RTT patient cells and isogenic controls. Our data gives evidence of proteomic alteration at early neurodevelopmental stages, suggesting alterations long before the phase that symptoms of RTT syndrome become apparent. Significant changes are associated with the GO enrichment analysis in biological processes cell-cell adhesion, actin cytoskeleton organization, neuronal stem cell population maintenance, and pituitary gland development, next to protein changes previously associated with RTT, i.e., dendrite morphology and synaptic deficits. Differential expression increased from early to late neural stem cell phases, although proteins involved in immunity, metabolic processes, and calcium signaling were affected throughout all stages analyzed. LIMITATIONS: The limitation of our study is the number of RTT patients analyzed. As the aim of our study was to investigate a large number of proteins, only one patient was considered, of which 3 different RTT iPSC clones and 3 isogenic control iPSC clones were included. Even though this approach allowed the study of mutation-induced alterations due to the usage of isogenic controls, results should be validated on different RTT patients to suggest common disease mechanisms. CONCLUSIONS: During early neuronal differentiation, there are consistent and time-point specific proteomic alterations in RTT patient cells carrying exons 3-4 deletion in MECP2. We found changes in proteins involved in pathway associated with RTT phenotypes, including dendrite morphology and synaptogenesis. Our results provide a valuable resource of proteins and pathways for follow-up studies, investigating common mechanisms involved during early disease stages of RTT syndrome. En ligne : http://dx.doi.org/10.1186/s13229-020-00344-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=427 [article] Quantitative proteomic analysis of Rett iPSC-derived neuronal progenitors [Texte imprimé et/ou numérique] / Suzy VARDERIDOU-MINASIAN, Auteur ; Lisa HINZ, Auteur ; Dominique HAGEMANS, Auteur ; Daniëlle POSTHUMA, Auteur ; Maarten ALTELAAR, Auteur ; Vivi M. HEINE, Auteur . - 38 p. Langues : Anglais (eng) in Molecular Autism > 11 (2020) . - 38 p. Mots-clés : Neuron differentiation  Quantitative mass spectrometry  Rett syndrome  TMT-10plex  iPSC Index. décimale : PER Périodiques Résumé : BACKGROUND: Rett syndrome (RTT) is a progressive neurodevelopmental disease that is characterized by abnormalities in cognitive, social, and motor skills. RTT is often caused by mutations in the X-linked gene encoding methyl-CpG binding protein 2 (MeCP2). The mechanism by which impaired MeCP2 induces the pathological abnormalities in the brain is not understood. Both patients and mouse models have shown abnormalities at molecular and cellular level before typical RTT-associated symptoms appear. This implies that underlying mechanisms are already affected during neurodevelopmental stages. METHODS: To understand the molecular mechanisms involved in disease onset, we used an RTT patient induced pluripotent stem cell (iPSC)-based model with isogenic controls and performed time-series of proteomic analysis using in-depth high-resolution quantitative mass spectrometry during early stages of neuronal development. RESULTS: We provide mass spectrometry-based quantitative proteomic data, depth of about 7000 proteins, at neuronal progenitor developmental stages of RTT patient cells and isogenic controls. Our data gives evidence of proteomic alteration at early neurodevelopmental stages, suggesting alterations long before the phase that symptoms of RTT syndrome become apparent. Significant changes are associated with the GO enrichment analysis in biological processes cell-cell adhesion, actin cytoskeleton organization, neuronal stem cell population maintenance, and pituitary gland development, next to protein changes previously associated with RTT, i.e., dendrite morphology and synaptic deficits. Differential expression increased from early to late neural stem cell phases, although proteins involved in immunity, metabolic processes, and calcium signaling were affected throughout all stages analyzed. LIMITATIONS: The limitation of our study is the number of RTT patients analyzed. As the aim of our study was to investigate a large number of proteins, only one patient was considered, of which 3 different RTT iPSC clones and 3 isogenic control iPSC clones were included. Even though this approach allowed the study of mutation-induced alterations due to the usage of isogenic controls, results should be validated on different RTT patients to suggest common disease mechanisms. CONCLUSIONS: During early neuronal differentiation, there are consistent and time-point specific proteomic alterations in RTT patient cells carrying exons 3-4 deletion in MECP2. We found changes in proteins involved in pathway associated with RTT phenotypes, including dendrite morphology and synaptogenesis. Our results provide a valuable resource of proteins and pathways for follow-up studies, investigating common mechanisms involved during early disease stages of RTT syndrome. En ligne : http://dx.doi.org/10.1186/s13229-020-00344-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=427

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