Project description:Angelman syndrome is caused by loss of funtional ubiquitin E3 ligase UBE3A and results in severe deley in cognitive and motor development. In neurons, UBE3A locates to the synapse and to the nucleus. Loss of nuclear UBE3A results in development of Angelman syndrome like symptoms in mice. UBE3A can function as transcriptional coactivator of steroid hormone receptors, but the entire function of UBE3A in the nucleus is still not clear. So we wanted to study differences in the transcriptome in neurons differentiated from iPSCs that were derived from patients with Angleman syndrome and normal controls.
Project description:mRNAseq on (1) isogenic control and Angelman Syndrome pluripotent stem cell-derived neurons or (2) antisense oligonucleotide-treated H9 hESC-derived neurons
Project description:UBE3A encodes a E3 ubiquitin ligase whose loss from the maternal allele causes the neurodevelopmental disorder Angelman syndrome. Previous studies of UBE3A function have not examined full Ube3a deletion in mouse, the complexity of imprinted gene networks in brain, nor the molecular basis of systems-level cognitive dysfunctions in Angelman syndrome. We therefore utilized a systems biology approach to elucidate how UBE3A loss impacts the early postnatal brain in a novel CRISPR/Cas9 engineered rat Angelman model of a complete Ube3a deletion. Strand-specific transcriptome analysis of offspring from maternally or paternally inherited Ube3a deletions revealed the expected parental expression patterns of Ube3a sense and antisense transcripts by postnatal day 2 (P2) in hypothalamus and day 9 (P9) in cortex, compared to wild-type littermates. The dependency of genome-wide effects on parent-of-origin, Ube3a genotype, and time (P2, P9) was investigated through transcriptome (RNA-seq of cortex and hypothalamus) and methylome (whole genome bisulfite sequencing of hypothalamus). Weighted gene co-expression and co-methylation network analyses identified co-regulated networks in maternally inherited Ube3a deletion offspring enriched in postnatal developmental processes including Wnt signaling, synaptic regulation, neuronal and glial functions, epigenetic regulation, ubiquitin, circadian entrainment, and splicing. Furthermore, we showed that loss of the paternal Ube3a antisense transcript resulted in both unique and overlapping dysregulated gene pathways with maternal loss, predominantly at the level of differential methylation. Together, these results provide a holistic examination of the molecular impacts of UBE3A loss in brain, supporting the existence of interactive epigenetic networks between maternal and paternal transcripts at the Ube3a locus.
Project description:We report a recurrent microdeletion syndrome causing mental retardation, epilepsy and variable facial and digital dysmorphisms. We describe nine patients, including six probands; two with de novo deletions, two who inherited the deletion from an affected parent, and two with unknown inheritance. The proximal breakpoint of the largest deletion is contiguous with breakpoint 3 (BP3) of the Prader-Willi/Angelman region extending 3.95 Mb distally to BP5. A smaller 1.5 Mb deletion has proximal breakpoint within the larger deletion (BP4) and shares the same distal BP5. This recurrent 1.5 Mb deletion contains six genes, including a candidate gene for epilepsy (CHRNA7) that is likely responsible for the observed seizure phenotype. The BP4-BP5 region undergoes frequent inversion, suggesting a possible link between this inversion polymorphism and recurrent deletion. The frequency of these microdeletions in mental retardation cases is ~0.3% (6/2082 tested), a prevalence comparable to that of the Williams, Angelman, and Prader-Willi syndromes. Keywords: microdeletion, genomic disorder, mental retardation, epilepsy
Project description:Angelman syndrome (AS) is a neurogenetic developmental disorder that results from the loss of E3 ubiquitin ligase UBE3A due to mutations in or deletions of the maternally inherited UBE3A allele. While mouse models of AS have implicated abnormal synaptic signaling and plasticity underlying behavioral dysfunction, how the loss of UBE3A contributes to hyperactivity of neuronal networks seen in AS patients remains unclear. Here, by utilizing human induced neurons and 3D cortical organoids derived from AS patient iPSCs and CRISPR-Cas9 mediated UBE3A KO hESCs, we uncovered a novel role of UBE3A in suppressing neuronal hyperexcitability via ubiquitin-mediated degradation of BK channels. More importantly, augmented BK channel activity in neurons manifested as increased intrinsic excitability of neurons and network level bursting and synchronization, which can be pharmacologically normalized by BK antagonists. Our study has illustrated the utility of modeling neurological diseases with human neural cells, and our results have provided new insights into underlying pathophysiological mechanisms and potential therapeutic strategy in Angelman syndrome.
2020-08-18 | GSE120225 | GEO
Project description:Transcriptional reprogramming restores UBE3A brain-wide and rescues behavioral phenotypes in an Angelman Syndrome mouse model