scholarly journals Neuronal network dysfunction in a human model for Kleefstra syndrome mediated by enhanced NMDAR signaling

2019 ◽  
Author(s):  
Monica Frega ◽  
Katrin Linda ◽  
Jason M. Keller ◽  
Güvem Gümüş-Akay ◽  
Britt Mossink ◽  
...  
Keyword(s):  
Neural Network ◽  
Neuronal Network ◽  
Cortical Neurons ◽  
Critical Role ◽  
Ips Cells ◽  
Autism Spectrum ◽  
Human Model ◽  
Human Neurons ◽  
Kleefstra Syndrome ◽  
The Impact

AbstractEpigenetic regulation of gene transcription plays a critical role in neural network development and in the etiology of Intellectual Disability (ID) and Autism Spectrum Disorder (ASD). However, little is known about the mechanisms by which epigenetic dysregulation leads to neural network defects. Kleefstra syndrome (KS), caused by mutation in the histone methyltransferase EHMT1, is a neurodevelopmental disorder with the clinical features of both ID and ASD. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. In addition, we created an isogenic set by genetically editing healthy iPS cells. Characterization of the neurons at the single-cell and neuronal network level revealed consistent discriminative properties that distinguished EHMT1-mutant from wildtype neurons. Mutant neuronal networks exhibited network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes were mediated by the upregulation of the NMDA receptor (NMDAR) subunit 1 and correlate with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. Furthermore, we show that EHMT1 deficiency in mice leads to similar neuronal network impairments and increased NMDAR function. Finally, we could rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Together, our results demonstrate a direct link between EHMT1 deficiency in human neurons and NMDAR hyperfunction, providing the basis for a more targeted therapeutic approach to treating KS.

scholarly journals Neuronal network dysfunction in a model for Kleefstra syndrome mediated by enhanced NMDAR signaling

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Monica Frega ◽  
Katrin Linda ◽  
Jason M. Keller ◽  
Güvem Gümüş-Akay ◽  
Britt Mossink ◽  
...  
Keyword(s):  
Neuronal Network ◽  
Cortical Neurons ◽  
Neurodevelopmental Disorder ◽  
Control Networks ◽  
Human Neurons ◽  
Kleefstra Syndrome ◽  
Nmdar Subunit ◽  
Induced Pluripotent ◽  
Reduced Rate ◽  
The Impact

Abstract Kleefstra syndrome (KS) is a neurodevelopmental disorder caused by mutations in the histone methyltransferase EHMT1. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. Neuronal networks of patient-derived cells exhibit network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes are mediated by upregulation of NMDA receptor (NMDAR) subunit 1 correlating with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. In mice EHMT1 deficiency leads to similar neuronal network impairments with increased NMDAR function. Finally, we rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Summarized, we demonstrate a direct link between EHMT1 deficiency and NMDAR hyperfunction in human neurons, providing a potential basis for more targeted therapeutic approaches for KS.

scholarly journals Age-Dependent Changes in Synaptic NMDA Receptor Composition in Adult Human Cortical Neurons

2020 ◽  
Vol 30 (7) ◽  
pp. 4246-4256 ◽  
Author(s):  
Chrysia M Pegasiou ◽  
Ardalan Zolnourian ◽  
Diego Gomez-Nicola ◽  
Katrin Deinhardt ◽  
James A R Nicoll ◽  
...  
Keyword(s):  
Human Brain ◽  
Cortical Neurons ◽  
Critical Role ◽  
Memory Storage ◽  
Neurosurgical Procedures ◽  
Adult Human ◽  
Age Related ◽  
Human Neurons ◽  
Age Dependent ◽  
Cortical Synapses

Abstract The molecular processes underlying the aging-related decline in cognitive performance and memory observed in humans are poorly understood. Studies in rodents have shown a decrease in N-methyl-D-aspartate receptors (NMDARs) that contain the GluN2B subunit in aging synapses, and this decrease is correlated with impaired memory functions. However, the age-dependent contribution of GluN2B-containing receptors to synaptic transmission in human cortical synapses has not been previously studied. We investigated the synaptic contribution of GluN2A and GluN2B-containing NMDARs in adult human neurons using fresh nonpathological temporal cortical tissue resected during neurosurgical procedures. The tissue we obtained fulfilled quality criteria by the absence of inflammation markers and proteomic degradation. We show an age-dependent decline in the NMDA/AMPA receptor ratio in adult human temporal cortical synapses. We demonstrate that GluN2B-containing NMDA receptors contribute to synaptic responses in the adult human brain with a reduced contribution in older individuals. With previous evidence demonstrating the critical role of synaptic GluN2B in regulating synaptic strength and memory storage in mice, this progressive reduction of GluN2B in the human brain during aging may underlie a molecular mechanism in the age-related decline in cognitive abilities and memory observed in humans.

Colombian parents of children with autism spectrum disorder: Perceptions, experiences, and expectations

2021 ◽  
Author(s):  
Marie Tejero Hughes ◽  
Sandra Magaña ◽  
Wendy Gonzales ◽  
Giselle Núñez ◽  
Marisol Moreno-Angarita
Keyword(s):  
Autism Spectrum Disorder ◽  
Parent Education ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Future Aspirations ◽  
Services And Supports ◽  
Parent Education Programs ◽  
The Impact

Abstract Families play a critical role in supporting their children with autism spectrum disorder (ASD) and in advocating for their health and educational needs. However, many families around the world experience social, emotional, and financial difficulties, as well as challenges navigating various systems in search for the services and supports their children require. Colombia has made some recent strides in supporting the needs of families of children with ASD, but there is still concern among families that their children are not receiving adequate services. Thus, we were interested in learning more about what it was like to parent a child with ASD in Colombia. In particular, we focused on investigating the families' perceptions, experiences, and aspirations for their child with ASD by conducting focus group interviews. Four primary themes emerged from these interviews with Colombian parents, which included the impact of the disability diagnosis on the family, the systemic and societal challenges they faced, the strengths they saw in their child, and their future aspirations and expectations for their child. Implications for developing culturally responsive parent education programs are discussed.

scholarly journals Age dependent changes in synaptic NMDA receptor composition in adult human cortical neurons

2020 ◽  
Author(s):  
C.M. Pegasiou ◽  
A. Zolnourian ◽  
D. Gomez-Nicola ◽  
K. Deinhardt ◽  
J.A.R. Nicoll ◽  
...  
Keyword(s):  
Human Brain ◽  
Cortical Neurons ◽  
Critical Role ◽  
Memory Storage ◽  
Neurosurgical Procedures ◽  
Adult Human ◽  
Age Related ◽  
Human Neurons ◽  
Age Dependent ◽  
Cortical Synapses

AbstractThe molecular processes underlying the ageing-related decline in cognitive performance and memory observed in humans are poorly understood. Studies in rodents have shown a decrease in N-methyl-D-aspartate receptors (NMDARs) that contain the GluN2B subunit in ageing synapses, and this decrease is correlated with impaired memory functions. However, the age-dependent contribution of GluN2B containing receptors to synaptic transmission in human cortical synapses has not been previously studied. We investigated the synaptic contribution of GluN2A and GluN2B containing NMDARs in adult human neurons using fresh non-pathological temporal cortical tissue resected during neurosurgical procedures. The tissue we obtained fulfilled quality criteria by the absence of inflammation markers and proteomic degradation. We show an age-dependent decline in the NMDA/AMPA receptor ratio in adult human temporal cortical synapses. We demonstrate that GluN2B containing NMDA receptors contribute to synaptic responses in the adult human brain with a reduced contribution in older individuals. With previous evidence demonstrating the critical role of synaptic GluN2B in regulating synaptic strength and memory storage in mice, this progressive reduction of GluN2B in the human brain during ageing may underlie a molecular mechanism in the age-related decline in cognitive abilities and memory observed in humans.

scholarly journals Selective behavioural impairments in mice heterozygous for the cross disorder psychiatric risk gene DLG2

2021 ◽  
Author(s):  
Rachel Pass ◽  
Niels Haan ◽  
Trevor Humby ◽  
Lawrence S Wilkinson ◽  
Jeremy Hall ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Motor Learning ◽  
Psychiatric Disorders ◽  
Cognitive Functions ◽  
Critical Role ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Brain Functions ◽  
The Impact

Mutations affecting DLG2 are emerging as a genetic risk factor associated with neurodevelopmental psychiatric disorders including schizophrenia, autism spectrum disorder and bipolar disorder. Discs large homolog 2 (DLG2) is a member of the membrane-associated guanylate kinase protein superfamily of scaffold proteins, a component of the post-synaptic density in excitatory neurons and regulator of synaptic function and plasticity. It remains an important question whether and how haploinsuffiency of DLG2 contributes to impairments in basic behavioural and cognitive functions that may underlie symptomatic domains in patients that cross diagnostic boundaries. Using a heterozygous Dlg2 mouse model we examined the impact of reduced Dlg2 expression on functions commonly impaired in neurodevelopmental psychiatric disorders including motor co-ordination and learning, pre-pulse inhibition and habituation to novel stimuli. The heterozygous Dlg2 mice exhibited behavioural impairments in long-term motor learning and long-term habituation to a novel context, but not motor co-ordination, initial responses to a novel context, PPI of acoustic startle or anxiety. We additionally showed evidence for the reduced regulation of the synaptic plasticity-associated protein cFos in the motor cortex during motor learning. The sensitivity of selective behavioural and cognitive functions, particularly those dependent on synaptic plasticity, to reduced expression of DLG2 give further credence for DLG2 playing a critical role in specific brain functions but also a mechanistic understanding of symptom expression shared across psychiatric disorders.

scholarly journals The impact of phosphorylated Pten at threonine 366 on cortical connectivity and behaviour

2021 ◽  
Author(s):  
Julia Ledderose ◽  
Jorge A Benitez ◽  
Amanda J Roberts ◽  
Rachel Reed ◽  
Willem Bintig ◽  
...  
Keyword(s):  
Sensory Processing ◽  
Cortical Neurons ◽  
Suppressor Gene ◽  
Autism Spectrum ◽  
Tumour Suppressor Gene ◽  
Repetitive Behaviour ◽  
Cortical Input ◽  
Brain Circuits ◽  
Neuron Size ◽  
The Impact

The lipid phosphatase Pten (phosphatase and tensin homologue on chromosome 10) is a key tumour suppressor gene and an important regulator of neuronal signalling. Pten mutations have been identified in patients with autism spectrum disorders, characterized by macrocephaly, impaired social interactions and communication, repetitive behaviour, intellectual disability, and epilepsy. Pten enzymatic activity is regulated by a cluster of phosphorylation sites at the C-terminus of the protein. Here we specifically focussed on the role of Pten T366 phosphorylation and generated a knock-in mouse line in which Pten T366 was substituted with alanine (PtenT366A/T366A). We identify that phosphorylation of Pten at T366 controls neuron size and connectivity of brain circuits involved in sensory processing. We show in behavioural tests that PtenT366/T366A mice exhibit cognitive deficits and selective sensory impairments, with significant differences in male individuals. We identify restricted cellular overgrowth of cortical neurons in PtenT366A/T366A brains, linked to increases in both dendritic arborization and soma size. In a combinatorial approach of anterograde and retrograde monosynaptic tracing using rabies virus, we characterize differences in connectivity to the primary somatosensory cortex of PtenT366A/T366A brains, with imbalances in long-range cortico-cortical input to neurons. We conclude that phosphorylation of Pten at T366 controls neuron size and connectivity of brain circuits involved in sensory processing and propose that PTEN T366 signalling may account for a subset of autism-related functions of Pten.

Impact of DRD2 polymorphisms on prolactin level in risperidone-treated Thai children and adolescent with autism spectrum disorders

2016 ◽  
Vol 33 (S1) ◽  
pp. S93-S93
Author(s):  
C. Sukasem ◽  
Y. Hongkaew
Keyword(s):  
Autism Spectrum Disorders ◽  
Children And Adolescents ◽  
Prolactin Level ◽  
Critical Role ◽  
Autism Spectrum ◽  
Nucleotide Polymorphisms ◽  
Genotype Frequencies ◽  
Adolescents With Autism ◽  
Spectrum Disorders ◽  
The Impact

IntroductionA large number of studies have reported that the prolactin concentration was significantly increased in the Taq1A A1 allele carriers because several reports revealed that individuals with the DRD2 Taq1A A1 allele have a reduced density of brain D2 receptors.ObjectiveThe main aim of this study was to identify the impact of pharmacogenetic markers associated with prolactin concentration in risperidone-treated children and adolescents with autism spectrum disorders.MethodsOne hundred and forty-seven children and adolescents with autism, aged 3 to 19, received risperidone. The clinical data of patients were recorded from medical records. Prolactin levels were measured by chemiluminescence immunoassay. Three CYP2D6 single nucleotide polymorphisms (SNPs), CYP2D6*4 (1846G>A), *10 (100C>T), and *41 (2988G>A), one gene deletion (*5), and DRD2 Taq1A (rs1800497) polymorphism were genotyped by TaqMan real-time PCR.ResultsThe three common allelic frequencies were CYP2D6*10 (55.10%), *1 (32.65%) and *5 (6.12%), respectively. Patients were grouped according to their CYP2D6 genotypes. The DRD2 genotype frequencies were Taq1A A2A2 (38.77%), A1A2 (41.50%), and A1A1 (19.73%), respectively. There were statistically significant differences in prolactin level of patients among the three groups (P = 0.033). The median prolactin level in patients with DRD2 Taq1A A2A2 (17.80 ng/mL) was significantly higher than A1A2 (17.10 ng/mL) and A1A1 (12.70 ng/mL).ConclusionDRD2 Taq1A A2A2 polymorphisms may be a critical role in an influence prolactin elevation during risperidone treatment in ASD.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Analyses of the Autism-associated Neuroligin-3 R451C Mutation in Human Neurons Reveals a Gain-of-Function Synaptic Mechanism

2021 ◽  
Author(s):  
Le Wang ◽  
Vincent R. Mirabella ◽  
Rujia Dai ◽  
Xiao Su ◽  
Ranjie Xu ◽  
...  
Keyword(s):  
Gene Networks ◽  
Autism Spectrum ◽  
Inhibitory Synapses ◽  
Excitatory Synapses ◽  
Gain Of Function ◽  
Protein Levels ◽  
Excitatory Transmission ◽  
Human Neurons ◽  
The Impact

Mutations in many synaptic genes are associated with autism spectrum disorders (ASDs), suggesting that synaptic dysfunction is a key driver of ASD pathogenesis. Among these mutations, the R451C-substitution in the NLGN3 gene that encodes the postsynaptic adhesion molecule Neuroligin-3 is noteworthy because it was the first specific mutation linked to ASDs. In mice, the corresponding Nlgn3 R451C-knockin mutation recapitulates social interaction deficits of ASD patients and produces synaptic abnormalities, but the impact of the NLGN3 R451C-mutation on human neurons has not been investigated. Here, we generated human knock-in neurons with the NLGN3 R451C-mutation. Strikingly, analyses of NLGN3 R451C-mutant neurons revealed that the R451C-mutation decreased NLGN3 protein levels but enhanced the strength of excitatory synapses without affecting inhibitory synapses. No significant cell death and endoplasmic reticulum stress were detected. Importantly, the augmentation of excitatory transmission was confirmed in vivo with human neurons transplanted into mouse forebrain. Using single-cell RNA-seq experiments with co-cultured excitatory and inhibitory NLGN3 R451C-mutant neurons, we identified differentially expressed genes in relatively mature human neurons that corresponded to synaptic gene expression networks. Moreover, gene ontology and enrichment analyses revealed convergent gene networks associated with ASDs and other mental disorders. Our findings suggest that the NLGN3 R451C-mutation induces a gain-of-function enhancement in excitatory synaptic transmission that may contribute to the pathophysiology of ASDs.

scholarly journals NRXN1α+/- is associated with increased excitability in ASD iPSC-derived neurons

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Sahar Avazzadeh ◽  
Leo R. Quinlan ◽  
Jamie Reilly ◽  
Katya McDonagh ◽  
Amirhossein Jalali ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neuronal Excitability ◽  
Cultured Cells ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Neuronal Firing ◽  
Calcium Transients ◽  
Electrophysiological Properties ◽  
Human Neurons ◽  
Co Morbidity

Abstract Background NRXN1 deletions are identified as one of major rare risk factors for autism spectrum disorder (ASD) and other neurodevelopmental disorders. ASD has 30% co-morbidity with epilepsy, and the latter is associated with excessive neuronal firing. NRXN1 encodes hundreds of presynaptic neuro-adhesion proteins categorized as NRXN1α/β/γ. Previous studies on cultured cells show that the short NRXN1β primarily exerts excitation effect, whereas the long NRXN1α which is more commonly deleted in patients involves in both excitation and inhibition. However, patient-derived models are essential for understanding functional consequences of NRXN1α deletions in human neurons. We recently derived induced pluripotent stem cells (iPSCs) from five controls and three ASD patients carrying NRXN1α+/- and showed increased calcium transients in patient neurons. Methods In this study we investigated the electrophysiological properties of iPSC-derived cortical neurons in control and ASD patients carrying NRXN1α+/- using patch clamping. Whole genome RNA sequencing was carried out to further understand the potential underlying molecular mechanism. Results NRXN1α+/- cortical neurons were shown to display larger sodium currents, higher AP amplitude and accelerated depolarization time. RNASeq analyses revealed transcriptomic changes with significant upregulation glutamatergic synapse and ion channels/transporter activity including voltage-gated potassium channels (GRIN1, GRIN3B, SLC17A6, CACNG3, CACNA1A, SHANK1), which are likely to couple with the increased excitability in NRXN1α+/- cortical neurons. Conclusions Together with recent evidence of increased calcium transients, our results showed that human NRXN1α+/- isoform deletions altered neuronal excitability and non-synaptic function, and NRXN1α+/- patient iPSCs may be used as an ASD model for therapeutic development with calcium transients and excitability as readouts.

scholarly journals The Autism Risk Factor CHD8 Is a Chromatin Activator in Human Neurons and Functionally Dependent on the ERK-MAPK Pathway Effector ELK1

2021 ◽  
Author(s):  
Bahareh Haddad Derafshi ◽  
Tamas Danko ◽  
Soham Chanda ◽  
Pedro Batista ◽  
Ulrike Litzenburger ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
De Novo ◽  
Mapk Pathway ◽  
Transcriptional Profiling ◽  
Distinct Group ◽  
Chromatin Accessibility ◽  
Autism Spectrum ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Human Neurons

Abstract The chromodomain helicase DNA-binding protein CHD8 is among the most frequently found de-novo mutations in autism spectrum disorder (ASD)1-4. Despite its prominent disease involvement, little is known about its molecular function in the human brain. CHD8 is believed to be a chromatin regulator, but mechanisms for its genomic targeting is also unclear. To elucidate the role of CHD8 in human neurons, we generated conditional loss-of-function alleles in pluripotent stem cells. Chromatin accessibility and transcriptional profiling showed that CHD8 is a potent chromatin opener and transcriptional activator of its direct neuronal targets, including a distinct group of ASD genes. We found the chromatin targeting of CHD8 to be highly context dependent. In human neurons, CHD8 was preferentially bound at promoter sequences which were significantly enriched in ETS motifs. Indeed, the chromatin state of ETS motif-containing promoters was preferentially affected upon loss of CHD8. Among the many ETS transcription factors, we found ELK1 to be the best correlated with CHD8 expression in primary human fetal and adult cortical neurons and most highly expressed in our ES cell-derived neurons. Remarkably, ELK1 was necessary to recruit CHD8 specifically to ETS motif-containing sites. These findings imply the functional cooperativity between ELK1, a key downstream factor of the MAPK/ERK pathway, and CHD8 on chromatin involvement in human neurons. THEREFORE, the MAPK/ERK/ELK1 axis may also play a role in the pathogenesis caused by CHD8 mutations5 .

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