Project description:This experiment comprises RNA-seq data used to study evolutionary differences between humans and mice in neuronal activity-dependent transcriptional responses. Activity-dependent transcriptional responses in developing human stem cell-derived cortical neurons were compared with those induced in developing primary- or stem cell-derived mouse cortical neurons 4 hours after KCl-induced membrane depolarisation. Activity-dependent transcriptional responses were also measured in aneuploid mouse neurons carrying human chromosome 21, allowing study of the regulation of Hsa21 genes, plus their mouse orthologs, side-by-side in the same cellular environment of a mouse primary neuron.
Project description:we used DNA microarray analysis to identify genes that are induced by neuronal activity in excitatory neurons at the time when inhibitory synapses are forming and maturing on them. Experiment Overall Design: We cultured cortical neurons for 7 DIV until the process of inhibitory synapse development was underway, and then depolarized the neurons with 50 mM of KCl to activate L-type voltage-sensitive calcium channels (L-VSCCs) for 0, 1 or 6 hours, the cells were lysed, mRNA isolated and hybridized to Affymetrix arrays. Data were collected from 3 independent experiments.
Project description:The stable formation of remote fear memories is thought to require neuronal gene induction in cortical ensembles that are activated during learning. However, the set of genes expressed specifically in these activated ensembles is not known; knowledge of such transcriptional profiles may offer insights into the molecular program underlying stable memory formation. Here we use RNA-Seq to identify genes whose expression is enriched in activated cortical ensembles labeled during associative fear learning. We first establish that mouse temporal association cortex (TeA) is required for remote recall of auditory fear memories. We then perform RNA-Seq in TeA neurons that are labeled by the activity reporter Arc-dVenus during learning. We identify 944 genes with enriched expression in Arc-dVenus+ neurons. These genes include markers of L2/3, L5b, and L6 excitatory neurons but not glial or inhibitory markers, confirming Arc-dVenus to be an excitatory neuron-specific, layer non-specific activity reporter. Cross comparisons to other transcriptional profiles show that 125 of the enriched genes are also activity-regulated in vitro or induced by visual stimulus in the visual cortex, suggesting that they may be induced generally in the cortex in an experience-dependent fashion. Prominent among the enriched genes are those encoding potassium channels that down-regulate neuronal activity, suggesting the possibility that part of the molecular program induced by fear conditioning may initiate homeostatic plasticity.
Project description:Astrocytes are implicated in neuronal development, particularly excitatory synaptogenesis, but their genome-wide impact is unclear. Using cell-type specific RNA-seq we show that cortical astrocytes induce widespread transcriptomic changes in developing cortical neurons. Rat cortical neurons were maintained in the presence or absence of mouse astrocytes, RNA-seq performed, and mixed-species RNA-seq reads sorted according to species. Cultures were also treated with TTX to abolish neuronal firing activity, to investigate the effects of the presence or absence activity-dependent signalling.
Project description:Kabuki Syndrome (KS) is a multisystemic rare disorder, characterized by growth delay, distinctive facial features, intellectual disability, and rarely autism spectrum disorder. This condition is mostly caused by de novo mutations of KMT2D, encoding a catalytic subunit of the COMPASS complex involved in enhancer regulation. KMT2D catalyzes the deposition of histone-3-lysine-4 mono-methyl (H3K4Me1) that marks active and poised enhancers. To assess the impact of KMT2D mutations in the chromatin landscape of KS tissues, we have generated patient-derived induced pluripotent stem cells (iPSC), which we further differentiated into neural crest stem cells (NCSC), mesenchymal stem cells (MSC) and cortical neurons (iN). In addition, we further collected blood samples from 5 additional KS patients. To complete our disease modeling cohort we generated an isogenic KMT2D mutant line from human embryonic stem cells, which we differentiated into neural precursor and mature neurons. Micro-electrode-array (MEA)-based neural network analysis of KS iNs revealed an altered pattern of spontaneous network-bursts in a Kabuki-specific pattern. RNA-seq profiling was performed to relate this aberrant MEA pattern to transcriptional dysregulations, revealing that dysregulated genes were enriched for neuronal functions, such as ion channels, synapse activity, and electrophysiological activity. Here we show that KMT2D haploinsufficiency tends to heavily affect the transcriptome of cortical neurons and differentiated tissues while sparing multipotent states, suggesting that KMT2D has a most prevalent role in terminally differentiated cell and activate transcriptional circuitry unique to each cell type. Moreover, thorough profiling of H3K4Me1 unveiled the almost complete uncoupling between this chromatin mark and the regulatory effects of KMT2D on transcription, which is instead reflected by a defect of H3K27Ac. By integrating RNA-seq with ChIP-seq data we defined TEAD and REST as the master effectors of KMT2D haploinsufficiency. Also, we identified a subset of genes whose regulation is controlled by the balance between KMT2D and EZH2 dosage. Finally, we identified the bona fide direct targets of KMT2D in healthy and KS mature cortical neurons and TEAD2 as the main proxy of KMT2D dysregulation in KS. Overall, our study provides the transcriptional and epigenomic characterization of patient-derived tissues as well as iPSCs and differentiated disease-relevant cell types, as well as the identification of KMT2D direct target in cortical neurons, together with the identification of a neuronal phenotype of the spontaneous electrical activity.
Project description:General anesthesia is a common clinical procedure yet can result in long term CNS-adverse effects, particularly in the elderly, or dementia patients. Suppression of cortical activity is a key feature of the anesthetic-induced unconscious state, with activity being a well-described regulator of pathways important for brain health. However the extent to which the effects of anesthesia go beyond simple suppression of neuronal activity is incompletely understood, as are its effects on non-neuronal cell types such as astrocytes, which are important integrators of both neuronal activity and inflammatory signalling. In order to address these questions, we performed a combination of RNA-seq and TRAP-seq (Translating Ribosome Affinity Purification, where astrocyte-specific translating mRNAs are sequenced) on mouse cortical tissue and primary cortical neurons.
Project description:For identification of transcripts enriched in neurites of primary cortical neurons, the cells were plated on a microporous membrane for isolation of neurites and soma. Extracted RNA was used for preparation of mRNA-seq, total RNA-seq or smRNA-seq libraries and Illumina sequencing. For neuronal zipcode identification protocol (N-zip) in mouse cortical neurons, we combined a massively parallel reporter assay with neurites/soma separation. Neurons, grown on a microporous membrane, were infected with a library of around 5000 oligos tiled across 3'UTRs of selected neurite-enriched transcripts, cloned downstream of GFP coding sequence. RNA was extracted from soma and neurites and reverse transcribed into cDNA. Amplicon libraries of 3'UTR reporters were prepared and subjected to Illumina sequencing. In the second round of N-zip, a library containing selected reporters from the first N-zip and their mutagenized versions (around 6000 oligos) were used. In the following rounds, N-zip was combined with knockdown of selected genes.
Project description:Induced pluripotent stem cell (iPSC)-derived cortical neurons present a powerful new model of neurological disease. Previous work has established that differentiation protocols produce cortical neurons but little has been done to characterise these at cellular resolution. In particular, it is unclear to what extent in vitro two-dimensional, relatively disordered culture conditions recapitulate the development of in vivo cortical layer identity. Single cell multiplex RT-qPCR was used to interrogate the expression of genes previously implicated in cortical layer or phenotypic identity in individual cells. Unexpectedly, 22.7% of neurons analysed frequently co-expressed canonical fetal deep and upper cortical layer markers, and this co-expression was also present at the level of translated protein. By comparing our results to available single cell RNA-seq data from human fetal and adult brain, we observed that this co-expression of layer markers was also seen in primary tissue. These results suggest that establishing neuronal layer identity in iPSC-derived or primary cortical neurons using canonical marker genes transcripts is unlikely to be informative. Single cell RNA-seq of 16 iPSC-derived cortical neurons. This dataset was used for normalization purposes for GSE67835.