Project description:Williams syndrome (WS) is a neurodevelopmental disorder caused by a genomic deletion of ~28 genes that results in a cognitive and behavioral profile marked by overall intellectual impairment with relative strength in expressive language and hypersocial behavior. Advancements in protocols for neuron differentiation from induced pluripotent stem cells allowed us to elucidate the molecular circuitry underpinning the ontogeny of Williams syndrome. In patient-derived stem cells and neurons, we determined the expression profile of the Williams-Beuren Syndrome Critical Region deleted genes and the genome-wide transcriptional consequences of the hemizygous genomic microdeletion at 7q11.23. Derived neurons displayed disease-relevant hallmarks and indicated novel aberrant pathways in WS neurons including over-activated Wnt signaling accompanying an incomplete neurogenic commitment. We show that haploinsufficiency of the ATP-dependent chromatin remodeler, BAZ1B, which is deleted in WS, significantly contributes to this differentiation defect. Chromatin-immunoprecipitation (ChIP-seq) revealed BAZ1B target gene functions are enriched for neurogenesis, neuron differentiation, and disease-relevant phenotypes. BAZ1B haploinsufficiency caused widespread gene expression changes in neural progenitor cells, and together with BAZ1B ChIP-seq target genes, explained 42% of the transcriptional dysregulation in WS neurons. BAZ1B contributes to regulating the balance between neural precursor self-renewal and differentiation and the differentiation defect caused by BAZ1B haploinsufficiency can be rescued by mitigating over-active Wnt signaling in neural stem cells. Altogether, these results reveal a pivotal role for BAZ1B in neurodevelopment and implicate its haploinsufficiency as a likely contributor to the neurological phenotypes in WS.
Project description:While psychiatric disorders (e.g., schizophrenia) and autism spectrum disorders (ASD) are typically associated with a deficit in social behavior, the opposite trait of hypersociability is exhibited by individuals with specific neurodevelopmental disorders, e.g., Angelman Syndrome (AS) and Williams-Beuren Syndrome (WBS). We have recently reported that the deletion of the miR379-410 cluster in mice led to hypersocial behavior. To study the roles of this miRNA cluster in the context of WBS, we sent for smallRNA sequencing RNA isolated from isogenic human iPSC-derived neurons harboring a deletion present in Williams-Beuren-Syndrome patients (7q11.23). Specifically, we found that members of the miR379-410 cluster were strikingly overrepresented among downregulated miRNAs in iNeurons harboring a deletion of the WBS critical region. Thus, we obtained the first evidence for the pathophysiological significance of the miR379-410 miRNA cluster in the context of WBS. We conclude that targeting this novel pathway could have therapeutic potential for WBS and other neurodevelopmental conditions characterized by social impairments.
Project description:There are a total of four samples each for this analysis. Each sample consists of the cells grown on three 10 cm culture plates. Each plate should have 2x106 cells for a total of 6x106 cells per sample when all three plates are combined. The first sample is undifferentiated human embryonic stem cells, the second sample is human glutamatergic neurons derived from those human embryonic stem cells, the third sample is undifferentiated human induced pluripotent stem cells and the fourth sample is human glutamatergic neurons derived from those human induced pluripotent stem cells.
Project description:We apply the cellular reprogramming experimental paradigm to two disorders caused by symmetrical copy number variations (CNV) of 7q11.23 and displaying a striking combination of shared as well as symmetrically opposite phenotypes: Williams Beuren syndrome (WBS) and 7q microduplication syndrome (7dup). Through a uniquely large and informative cohort of transgene-free patient-derived induced pluripotent stem cells (iPSC), along with their differentiated derivatives, we find that 7q11.23 CNV disrupt transcriptional circuits in disease-relevant pathways already at the pluripotent state. These alterations are then selectively amplified upon differentiation into disease-relevant lineages, thereby establishing the value of large iPSC cohorts in the elucidation of disease-relevant developmental pathways. In addition, we functionally define the quota of transcriptional dysregulation specifically caused by dosage imbalances in GTF2I (also known as TFII-I), a transcription factor in 7q11.23 thought to play a critical role in the two conditions, which we found associated to key repressive chromatin modifiers. Finally, we created an open-access web-based platform (accessible at http://bio.ieo.eu/wbs/ ) to make accessible our multi-layered datasets and integrate contributions by the entire community working on the molecular dissection of the 7q11.23 syndromes. We differentiated a representative subset of patient-derived iPSC lines into three disease-relevant lineages: dorsal telencephalic progenitors (Neural Progenitor Cells, NPC), Neural Crest Stem Cells (NCSC) and Mesenchymal Stem Cells (MSC). We profiled NCSC and NPC through microarray (current dataset), and MSC through RNA-seq.
Project description:Williams-Beuren Syndrome (WBS) is caused by the microdeletion of approximately 25 genes on chromosome 7q11.23, and is characterized by a spectrum of cognitive and behavioural features. We generated cortical neurons from a WBS individual and unaffected (WT) control by directed differentiation of induced pluripotent stem cells (iPSCs). Single cell mRNA analyses and immunostaining demonstrated very efficient production of differentiated cells expressing markers of mature neurons of mixed subtypes and from multiple cortical layers. We found that passive membrane properties were comparable in these WBS and WT neurons, but there was a profound alteration in action potentials, with significantly prolonged WBS repolarization times and a WBS deficit in voltage-activated K+ currents. Miniature excitatory synaptic currents were normal, indicating that unitary excitatory synaptic transmission was not altered. Gene expression profiling identified 136 negatively enriched gene sets in WBS compared to WT neurons. These genes are involved in synaptic transmission and assembly, cation transport, axon guidance and elastic fibre pathways, and some encode ion channels. Our findings provide insight into gene dysregulation and electrophysiological defects in WBS patient neurons.
Project description:Copy number variations (CNVs) at 7q11.23 cause Williams-Beuren (WBS) and 7q microduplication syndromes (7Dup), two neurodevelopmental disorders with shared and opposite cognitive-behavioral phenotypes. Using patient-derived and isogenic neurons, we integrated transcriptomics, translatomics and proteomics to elucidate the molecular underpinnings of this dosage effect. We found that 7q11.23 CNVs cause opposite alterations in neuronal differentiation and neuronal excitability. Here, the 7q11.23 CNV altered proteome in iPSC differentiating neurons was measured by a fast SWATH-MS method.
Project description:Induced pluripotent stem cell (iPSC) models of neurodevelopmental disorders (NDDs) have promoted an understanding of commonalities and differences within or across patient populations by revealing the underlying molecular and cellular mechanisms contributing to disease pathology. Here, we focus on developing a human model for PPP2R5D-related NDD, called Jordan syndrome, which has been linked to Early-Onset Parkinson’s Disease (EOPD). This disease model includes patient-derived induced pluripotent stem cells (iPSCs) which were differentiated into neural stem cells (NSCs) and subsequently specified into a midbrain neural stem cell and neuronal state. We sought to understand the underlying molecular and cellular phenotypes across multiple cell states and neuronal subtypes in order to gain insight into Jordan syndrome pathology. Our work revealed that iPSC-derived midbrain neurons from Jordan syndrome patients display significant differences in dopamine-associated pathways and neuronal architecture.
2023-11-30 | GSE238213 | GEO
Project description:Motor neurons derived from human induced Pluripotent Stem Cells.
Project description:We apply the cellular reprogramming experimental paradigm to two disorders caused by symmetrical copy number variations (CNV) of 7q11.23 and displaying a striking combination of shared as well as symmetrically opposite phenotypes: Williams Beuren syndrome (WBS) and 7q microduplication syndrome (7dupASD). Through a uniquely large and informative cohort of transgene-free patient-derived induced pluripotent stem cells (iPSC), along with their differentiated derivatives, we find that 7q11.23 CNV disrupt transcriptional circuits in disease-relevant pathways already at the pluripotent state. These alterations are then selectively amplified upon differentiation into disease-relevant lineages, thereby establishing the value of large iPSC cohorts in the elucidation of disease-relevant developmental pathways. In addition, we functionally define the quota of transcriptional dysregulation specifically caused by dosage imbalances in GTF2I (also known as TFII-I), a transcription factor in 7q11.23 thought to play a critical role in the two conditions, which we found associated to key repressive chromatin modifiers. Finally, we created an open-access web-based platform (accessible at http://bio.ieo.eu/wbs/ ) to make accessible our multi-layered datasets and integrate contributions by the entire community working on the molecular dissection of the 7q11.23 syndromes.