FOXG1-dependent dysregulation of GABA/glutamate neuron differentiation in autism spectrum disorders
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ABSTRACT: Autism spectrum disorder (ASD) is a disorder of brain development believed, in most cases, to be of genetic origin. We use induced pluripotent stem cells (iPSCs)-derived 3-dimensional neural cultures (organoids) in patients with ASD and macrocephaly to investigate neurodevelopmental alterations that cause this form of ASD. By using transcriptome analyses, we identified modules of co-expressed genes significantly upregulated in ASD patients compared to non-ASD first-degree family members.
Project description:Autism spectrum disorder (ASD) is a disorder of brain development. Most cases lack a clear etiology or genetic basis, and the difficulty of re-enacting human brain development has precluded understanding of ASD pathophysiology. Here we use three-dimensional neural cultures (organoids) derived from induced pluripotent stem cells (iPSCs) to investigate neurodevelopmental alterations in individuals with severe idiopathic ASD. While no known underlying genomic mutation could be identified, transcriptome and gene network analyses revealed upregulation of genes involved in cell proliferation, neuronal differentiation, and synaptic assembly. ASD-derived organoids exhibit an accelerated cell cycle and overproduction of GABAergic inhibitory neurons. Using RNA interference, we show that overexpression of the transcription factor FOXG1 is responsible for the overproduction of GABAergic neurons. Altered expression of gene network modules and FOXG1 are positively correlated with symptom severity. Our data suggest that a shift toward GABAergic neuron fate caused by FOXG1 is a developmental precursor of ASD.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disease with complex heterogeneity and aberrations in multiple levels of neurobiology. Recently, our understanding of the molecular abnormalities in ASD has been greatly expanded through transcriptomic analyses of postmortem brains. However, a crucial molecular pathway involved in synaptic development, RNA editing, has not yet been studied on a genome-wide scale. Here we profiled the global patterns of adenosine-to-inosine (A-to-I) editing in a large cohort of ASD cortices and cerebella. Strikingly, we observed a global bias of hypoediting in ASD brains, common to different brain regions and involving many genes with critical neurological function. The large-scale RNA editing changes allowed us to reveal novel insights of RNA editing regulation. Through genome-wide protein-RNA binding analyses and detailed molecular assays, we show that the Fragile X proteins, FMRP and FXR1P, interact with ADAR protens and modulate A-to-I editing. Furthermore, we observed convergent patterns of RNA editing alterations between ASD and Fragile X syndrome, thus establishing RNA editing as a novel molecular link underlying these two highly related diseases. Our findings support a role for RNA editing dysregulation in ASD pathophysiology and highlight novel mechanisms for RNA editing regulation.
Project description:To examine how activation of different toll-like receptors (TLR) impacts gene expression in Autism Spectrum Disorder (ASD), we cultured peripheral blood monocytes from children with ASD, Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) or Asperger and typically developing children and treated them with either lipoteichoic acid (LTA) or lipopolysaccharide (LPS) to activate LTR2 or 4 respectively. Following 24 hours of stimulation, we then performed RNA sequencing to profile mRNA responses between non-treated (NT), LTA and LPS treated samples for each diagnosis (control or ASD).
Project description:Autism Spectrum Disorder (ASD) is a common pediatric cognitive disorder with high heritability. Yet no single genetic variant has accounted for more than a small fraction of cases. We sought to determine whether we could classify patients as having ASD vs. controls solely based on a multi-gene expression profiling of their peripheral blood cells.
Project description:We developed a human cerebral organoid model derived from induced pluripotent stem cells (iPSCs) with targeted genome editing to abolish protein expression of the Contactin Associated Protein-like 2 (CNTNAP2) autism spectrum disorder (ASD) risk gene, mimicking loss-of-function mutations seen in patients. CNTNAP2-/- cerebral organoids displayed accelerated cell cycle, ventricular zone disorganisation and increased cortical folding. Proteomic analysis revealed disruptions in glutamatergic/GABAergic synaptic pathways and neurodevelopment, highlighting increased protein expression of corticogenesis and neurodevelopment-related genes such as Forkhead box protein G1 (FOXG1) and Paired box 6 (PAX6). Transcriptomic analysis revealed differentially expressed genes (DEG) belonging to inhibitory neuron-related gene networks. Interestingly, there was a weak correlation between the transcriptomic and proteomic data, suggesting nuanced translational control mechanisms. Along these lines we find upregulated Protein Kinase B (Akt)/mechanistic target of rapamycin (mTOR) signalling in CNTNAP2-/- organoids. Spatial transcriptomics analysis of CNTNAP2-/- ventricular zones demonstrated pervasive changes in gene expression, particularly in PAX6- cells, implicating upregulation of cell cycle regulation pathways, synaptic and glutamatergic/GABAergic pathways. We noted a significant overlap of all omics datasets with idiopathic ASD (macrocephaly) iPSC-derived telencephalic organoids DEG, where FOXG1 was upregulated, along with aberrant expression of Glutamate decarboxylase 1 (GAD1) and T-Box Brain Transcription Factor 1 (TBR1), suggesting altered GABAergic/glutamatergic neuron development. These findings potentially highlight a shared mechanism in the early cortical development of various forms of ASD, further elucidate the role of CNTNAP2 in ASD pathophysiology and cortical development and pave the way for targeted therapies using cerebral organoids as preclinical models.
Project description:Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication deficits and repetitive behaviors. MicroRNAs (miRNAs) have been recently recognized as potential biomarkers of ASD as they are dysregulated in various tissues of individuals with ASD. However, it remains unclear whether miRNA expression is altered in individuals with high-functioning ASD. Here, we investigated the miRNA expression profile in peripheral blood from adults with high-functioning ASD, and age and gender-matched healthy controls. Our findings may provide insights regarding the molecular clues for recognizing high-functioning ASD.
Project description:The association between macrocephaly and autism spectrum disorder (ASD) suggests that the mechanisms underlying excessive neural growth could contribute to ASD pathogenesis. Consistently, neural progenitor cells (NPCs) derived from induced pluripotent stem cells (iPSCs) of ASD individuals with early developmental brain enlargement are inherently more proliferative than control NPCs. Here, we show that hiPSC-derived NPCs from ASD individuals with macrocephaly display an altered DNA replication program and increased DNA damage. When compared to the control NPCs, high throughput genome-wide translocation sequencing (HTGTS) demonstrates that ASD-derived NPCs harbored elevated DNA double-strand breaks in replication stress-susceptible genes, some of which are associated with ASD pathogenesis. Our results provide a mechanism linking hyperproliferation of NPCs with the pathogenesis of ASD by disrupting long neural genes involved in cell-cell adhesion and migration.
Project description:Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by delayed/abnormal language development, deficits in social interaction, repetitive behaviors and restricted interests. The heterogeneity in clinical presentation of ASD, likely due to different etiologies, complicates genetic/biological analyses of these disorders. DNA microarray analyses were conducted on 116 lymphoblastoid cell lines (LCL) from individuals with idiopathic autism who are divided into 3 phenotypic subgroups according to severity scores from the commonly used Autism Diagnostic Interview-Revised questionnaire and age-matched, nonautistic controls. Statistical analyses of gene expression data from control LCL against that of LCL from ASD probands identify genes for which expression levels are either quantitatively or qualitatively associated with phenotypic severity. Comparison of the significant differentially expressed genes from each subgroup relative to the control group reveals differentially expressed genes unique to each subgroup as well as genes in common across subgroups. Among the findings unique to the most severely affected ASD group are genes that regulate circadian rhythm, which has been shown to have multiple effects on neurological as well as metabolic functions commonly dysregulated in autism. Among the genes common to all 3 subgroups of ASD are 5 novel genes which appear to associate with androgen sensitivity, which may underlie the strong 4:1 bias towards affected males. Gene expression profiling of 116 LCL from autistic (87) and nonautistic (29) individuals were obtained using a custom-printed DNA microarray containing 39,936 elements (TIGR 40K Human array, GPL3427) and a reference design in which each sample was compared to the Stratagene Universal Human RNA standard. The 87 autistic samples were divided into phenotypic subgroups (language, mild, savant) on the basis of cluster analyses of scores from an autism diagnostic questionnaire, the Autism Diagnostic Interview-Revised instrument. Differentially expressed genes were determined for all autistic vs. control groups, as well as for each of 3 phenotypic ASD groups and controls.