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:Sensory inputs activate sparse ensembles of neurons in the dentate gyrus of the hippocampus, but how eligibility of individual neurons to recruitment is determined remains elusive. We identified thousands of largely bistable (CpG methylated or unmethylated) regions within neuronal gene bodies, established during mouse dentate gyrus development. Reducing DNA methylation and the proportion of the methylated epialleles at bistable regions compromised novel context-induced neuronal activation. Conversely, increasing methylation and the frequency of the methylated epialleles at bistable regions enhanced intrinsic excitability. Single-nuclei profiling revealed enrichment of specific epialleles from a subset of bistable regions in activated neurons. Genes displaying both differential methylation and expression in activated neurons defined a network of proteins regulating neuronal excitability and structural plasticity. We propose a model in which bistable regions create neuron heterogeneity, and constellations of exonic epialleles dictate, via modulating gene expression and neuronal excitability, eligibility to a coding ensemble
Project description:Circuit neuroscience has made great progress by linking neuronal function to marker gene expression, allowing the specific investigation of otherwise indistinguishable neuronal ensembles. Here, we performed next generation sequencing on two functionally and genetically distinct interneuronal populations marked by the expression of protein kinase C δ (PKCδ) or somatostatin (SST) in the central amygdala (CEA) of mice, which are known to play distinct and sometimes opposing roles in emotion processing. Making their gene expression profile known will aid in forming hypotheses of how different neurotransmitters or psychoactive drugs could alter information processing in these neurons.
Project description:Maladaptive reward seeking is a hallmark of cocaine use disorder. To develop therapeutic targets, it is critical to understand the neurobiological changes specific to cocaine-seeking without altering the seeking of natural rewards, e.g., sucrose. The prefrontal cortex (PFC) and the nucleus accumbens core (NAcore) are known regions associated with cocaine- and sucrose-seeking ensembles, i.e., a sparse population of co-activated neurons. Within ensembles, transcriptomic alterations in the PFC and NAcore underlie the learning and persistence of cocaine- and sucrose-seeking behavior. However, transcriptomes exclusively driving cocaine seeking independent from sucrose seeking have not yet been defined using a within-subject approach. Using Ai14:cFos-TRAP2 transgenic mice in a dual cocaine and sucrose self-administration model, we fluorescently sorted (FACS) and characterized (RNAseq) the transcriptomes defining cocaine- and sucrose-seeking ensembles. We found reward- and region-specific transcriptomic changes that will help develop clinically relevant genetic approaches to decrease cocaine-seeking behavior without altering non-drug reward-based positive reinforcement.
2023-11-08 | GSE247029 | GEO
Project description:IRK mediated enhanced membrane excitability in accumbens neuronal ensembles promotes incubation of cocaine craving
Project description:SH-SY5Y neuroblastoma cells are widely used as in vitro neuronal model. They can be induced to a differentiated phenotype, presenting neurites and synaptical-like structures in response to retinoic (RA) acid and brain-derived neurotrophic factor (BDNF), providing a model to analyze neuronal differentiation. We report a large scale MS quantification of SH-SY5Y cells proteome during its differentiation process after treatment with RA/BDNF. Using isobaric tags for relative and absolute quantification (iTRAQ) approach and phosphopeptide enrichment protocols, we identified a total of 5587 proteins, 366 of them showed differential abundance between both conditions of culture. Differentiated SH-SY5Y cells showed regulation of proteins and phosphosites strongly related to neuronal development, in contrast, undifferentiated cells expressed proteins more related to cell proliferation and control of cell cycle. Interactive network analysis covered processes as focal adhesion, cytoskeleton dynamics and neurodegenerative diseases and pathway analysis displayed regulation of mitogen-activated protein kinase and phosphoinositide 3-kinase/Akt signaling pathways mainly; the proteins involved in those processes might be considered as markers for neuronal differentiation. Overall the data collection presented here can be explored for any studies which intent to use SH-SY5Y as neuronal model.
Project description:Alzheimer’s disease (AD) is a neurodegenerative disease that causes physical damage to neuronal connections, leading to brain atrophy. This disruption of synaptic connections results in mild to severe cognitive impairments. Unfortunately, no effective treatment is currently known to prevent or reverse the symptoms of AD. The aim of this study was to investigate the effects of 3 synthetic peptides on an AD in vitro model represented by differentiated SH-SY5Y neuroblastoma cells exposed to retinoic acid (RA) and brain-derived neurotrophic factor (BDNF).
Project description:Processes shaping the 3-dimensional (3D) human genome remain elusive. We present Chrom3D, a user-friendly 3D whole-genome modeling software that dynamically simulates the radial positioning of topological domains (TADs) in the nucleus. We integrate Hi-C and lamin-associated domain (LAD) information to generate high-resolution ensembles of models that recapitulate single-cell TAD distribution. Chrom3D reveals dynamic TADs and TADs constitutively placed at the nuclear periphery or nuclear interior. TAD stability in these compartments is consistent with differences in TAD gene density and expression level. A- and B-type lamins as radial constraints differentially skew LAD distribution towards the nuclear interior or periphery. Predictions of radial LAD placement in model ensembles are validated by quantitative imaging. Chrom3D models reveal unexpected features of LAD regulation in the nuclear interior in cells from laminopathy patients with a LMNA mutation. Integration of radial positioning constraints in 3D genome models enables the study spatial gene regulation in disease contexts.
Project description:Despite widespread interest in using human stem cells in neurological disease modeling, a suitable model system to study human neuronal connectivity is lacking. Here, we report a protocol for efficient differentiation of hippocampal pyramidal neurons and an in vitro model for hippocampal neuronal connectivity. We developed an embryonic stem cell (ESC)- and induced pluripotent stem cell (iPSC)-based protocol to differentiate human CA3 pyramidal neurons from patterned hippocampal neural progenitor cells (NPCs). This differentiation induces a comprehensive patterning and generates multiple CA3 neuronal subtypes. The differentiated CA3 neurons are functionally active and readily form neuronal connection with dentate granule (DG) neurons in vitro, recapitulating the synaptic connectivity within the hippocampus. When we applied this neuronal co-culture approach to study connectivity in schizophrenia, we found deficits in spontaneous activity in patient iPSC derived DG–CA3 co-culture by multi-electrode array recording. In addition, both multi-electrode array recording and whole cell patch clamp electrophysiology revealed a reduction in spontaneous and evoked neuronal activity in CA3 neurons derived from schizophrenia patients. Altogether these results underscore the relevance of this new model in studying diseases with hippocampal vulnerability.