Project description:The suppression of fear memory in the absence of danger (fear extinction) requires coordinated neural activity within the amygdala and medial prefrontal (prelimbic and infralimbic) cortex. Any behavior has a transcriptomic signature that is modified by environmental experiences, and specific genes are involved in functional plasticity and synaptic wiring during fear memory and extinction. In the present study, we investigated the effects of optogenetic manipulations of prelimbic pyramidal neurons on amygdala gene expression to analyze the specific transcriptional pathways involved in fear extinction. To this aim, transgenic mice (Thy1-COP4) having cortical and amygdala pyramidal neurons optogenetically excitable were (or not) fear-conditioned. During the extinction phase, the mice received optogenetic (or sham) stimulations to maintain the activation of the prelimbic pyramidal neurons and impair fear extinction. At the end of behavioral testing, electrophysiological (Excitatory Post-Synaptic Currents) and morphological (spinogenesis) correlates were evaluated in the pyramidal neurons of prelimbic cortex. Furthermore, transcriptomic cell-specific RNA-analyses (differential gene expression profiling and functional enrichment analyses) were performed in amygdala pyramidal neurons. Results demonstrate that pyramidal neurons of prelimbic cortex are involved in modulation of the fear responses during extinction phase and their optogenetic stimulation in fear-conditioned mice results in strong modifications of the amygdala transcriptome. Understanding the transcriptomic architecture of fear extinction may facilitate the comprehension of fear-related disorders.
Project description:Analysis of amygdala RNA expression after auditory fear conditioning in mice. Total RNA from three groups was obtained: 1) Home Cage (HC) 2) 30 minutes after Fear Conditioning (FC) 3) 2 hours after FC.
Project description:Analysis of amygdala RNA expression 2 hours after auditory fear conditioning in mice with and without previous exposure to acute immobilization stress Total RNA from three groups was obtained: 1) Home Cage (HC) 2) Fear Conditioning (FC) 3) Immobilization (IMO) + FC
Project description:Npas4 CUT&Tag dataset, Adult male WT C57BL/6J mice underwent discriminative fear conditioning and immediately injected saline. 90 minutes after fear conditioning, The amygdala tissue was extracted for further experiment. Npas4 CUT&Tag was performed to elucidate possible downstream targets which contributes regulation of fear expression during fear retreival.
Project description:Here we show that ?-catenin mediates pro-resilient and anxiolytic effects in mice in the nucleus accumbens (NAc), a key brain reward region, an effect that is mediated by ?-catenin signaling in D2-type medium spiny neurons (MSNs) specifically. Conversely, blocking ?-catenin function in NAc promotes susceptibility to chronic stress, and we show evidence of robust suppression of ?-catenin transcriptional activity in the NAc both of depressed humans examined postmortem as well as of mice that display a susceptible phenotype after chronic stress, with a converse upregulation in mice that are stress resilient. Using ChIP-seq, we demonstrate a global, genome-wide enrichment of ?-catenin in the NAc of resilient mice, and specifically identify Dicer1—important in small RNA (e.g., microRNA [miRNA]) biogenesis—as a critical ?-catenin target gene involved in mediating a resilient phenotype. Small RNA-seq after excising ?-catenin from the NAc in the context of chronic stress reveals dynamic ?-catenin-dependent miRNA regulation associated with resilience. Control: 2 samples, Resilient: 2 samples, Susceptible: 2 samples; DNA input: 1 sample.
Project description:Chronic social defeat (CSD) in mice has been increasingly employed in experimental resilience research. Particularly, the degree of CSD-induced social avoidance is used to classify animals into resilient (socially non-avoidant) versus susceptible (avoidant). Inspired by human data pointing to threat-safety discrimination and responsiveness to extinction training of aversive memories as characteristics of resilient individuals, we here describe a translationally informed stratification which identified three phenotypic subgroups of mice following CSD: the Discriminating-avoiders, characterised by successful social threat-safety discrimination and successful extinction of social avoidance; the Indiscriminate-avoiders, showing fear generalisation, and the Non-avoiders (absence of social avoidance) displaying impaired conditioned learning. Furthermore, and supporting the biological validity of our approach, we uncovered subgroup-specific transcriptional signatures in classical fear conditioning and anxiety-related brain regions. Our reconceptualisation of resilience in mice refines the currently used dichotomous classification and contributes to advancing future translational approaches.
Project description:Analysis of amygdala RNA expression 2 hours after auditory fear expression test in mice with and without previous exposure to acute immobilization stress.
Project description:miRNA profiling was carried out using the miRCURY LNA™ microRNA Array (6th gen - hsa, mmu & rno) miRNA were profiled in amygdala brain tissue obtained from adult mice 30 mins after auditory fear conditioning and expression levels compared to tissue obtained from Home cage controls Adult male mice were fear conditioned using tone-shock pairings and brains were harvested 30 mins later. The brains of Home Cage controls and Fear Conditioned animals (n = 4/group) were then punched to collect amygdala tissue. miRNA were extracted using the Qiagen miRNeasy Kit, and then shipped to Exiqon. Exiqon performed labeling, hybridization and data analysis after use of the miRCURY LNA™ microRNA Array (6th gen - hsa, mmu & rno). https://www.exiqon.com/ls/Documents/Scientific/miRCURY-LNA-microRNA-Array-6th-gen-hsa-mmu-rno-manual.pdf
Project description:Purpose: To identify genes differentially expressed in parvalbumin-positive (PV) interneurons of the hippocampus in non-defetaed (CTRL), stress-susceptible and stress-resilient mice. Method: Translating Ribosome Affinity Purification (TRAP) to isolate RNA from PV+ cells, cDNA synthesis and next generation RNAseq using Illumina Nextseq 500 sequencer. Results: RNA-seq revealed 458 DEGs between non-defeated and resilient mice, 1976 DEGs in non-defeated and susceptible mice, and 3475 DEGs in resilient and susceptible mice.