Project description:Adolescence is a critical period in cognitive and emotional development, characterized by high levels of social interaction and increases in risk-taking behavior including binge drinking. Adolescent exposure to social stress and binge ethanol have individually been associated with the development of social, emotional, and cognitive deficits, as well as increased risk for alcohol use disorder. Disruption of cortical development by early life social stress and/or binge drinking may partly underlie these enduring emotional, cognitive, and behavioral effects. The study goal is to implement a novel neighbor housing environment to identify the effects of adolescent neighbor housing and/or binge ethanol drinking on (1) a battery of emotional and cognitive tasks (2) adult ethanol drinking behavior, and (3) the nucleus accumbens and prefrontal cortex transcriptome. Adolescent male and female C57BL/6J mice were single or neighbor housed with or without access to intermittent ethanol. One cohort underwent behavioral testing during adulthood to determine social preference, expression of anxiety-like behavior, cognitive performance, and patterns of ethanol intake. The second cohort was sacrificed in late adolescence and brain tissue was used for transcriptomics analysis. As adults, single housed mice displayed decreased social interaction, deficits in the novel object recognition task, and increased anxiety-like behavior, relative to neighbor-housed mice. There was no effect of housing condition on adolescent or adult ethanol consumption. Adolescent ethanol exposure did not alter adult ethanol intake. Transcriptomics analysis revealed that adolescent housing condition and ethanol exposure resulted in differential expression of genes related to synaptic plasticity in the nucleus accumbens and genes related to methylation, the extracellular matrix and inflammation in the prefrontal cortex. The behavioral results indicate that social interaction during adolescence via the neighbor housing model may protect against emotional, social, and cognitive deficits. In addition, the transcriptomics results suggest that these behavioral alterations may be mediated in part by dysregulation of transcription in the frontal cortex or the nucleus accumbens
Project description:Population-based studies show cannabis use doubles the risk of developing schizophrenia especially when use occurs in early adolescence (prior to age 15). However, the cause-and-effect mechanisms are largely unknown. To investigate the effect of cannabis on brain maturation and relation to the development of psychosis-like behaviours in adulthood, we treated young adolescent mice with vehicle or cannabis extract once a day for 2 weeks between postnatal days 14 and 28, and then collected hippocampal tissue for microarray analysis 12 weeks later. We identify a total of 78 differentially expressed genes (25 upregulated and 53 downregulated; p<0.05, fold change ± 1.2) and validate increases in dopamine D2 receptor (Drd2) and fatty acid amide hydrolase (Faah). Changes in Faah expression were limited to the hippocampus however Drd2 also increased in striatum but not prefrontal cortex or amygdala. When tested in adulthood with a behavioural panel relevant to schizophrenia, cannabis-treated mice displayed lower anxiety in the elevated zero-maze, decreased social preference, increased social novelty preference, mild cognitive impairments in a spatial version of the novel object recognition task and absence of latent inhibition when compared to vehicle controls. Adolescent treatment with cannabis extract thus lead to long-lasting changes in gene expression within the hippocampus which together result in behavioural deficits consistent with the negative and positive symptoms of schizophrenia.
Project description:Typical adolescent neurodevelopment is marked by decreases in grey matter (GM) volume, increases in myelination, measured by fractional anisotropy (FA), and improvement in cognitive performance. To understand how epigenetic changes, methylation (DNAm) in particular, may be involved during this phase of development, we studied cognitive assessments, DNAm from saliva, and neuroimaging data from a longitudinal cohort of normally developing adolescents, aged nine to fourteen. We extracted networks of methylation with patterns of correlated change using a weighted gene correlation network analysis (WCGNA). Modules from these analyses, consisting of co-methylation networks, were then used in multivariate analyses with GM, FA, and cognitive measures to assess the nature of their relationships with cognitive improvement and brain development in adolescence. This longitudinal exploration of co-methylated networks revealed an increase in correlated epigenetic changes as subjects progressed into adolescence. Co-methylation networks enriched for pathways involved in neuronal systems, potassium channels, neurexins and neuroligins were both conserved across time as well as associated with maturation patterns in GM, FA, and cognition, revealing epigenetic mechanisms that could be involved in adolescent neural development.
Project description:MicroRNA (miRNA) dysregulation is well-documented in psychiatric disease, but miRNA dynamics during adolescent and early adult brain maturation, when symptoms first appear for many of these diseases, remain poorly understood. Here, we use RNA sequencing to examine miRNAs and their mRNA targets in cortex and hippocampus from early, mid-, and late adolescent and adult mice. We also use Quantitative Proteomics by tandem mass tag mass spectrometry (TMT-MS) to examine protein dynamics in cortex from the same subjects.
Project description:Background: Adolescent cannabis use leads to long-lasting behavioral changes involving cognitive and reward processes. However, the underlying molecular mechanisms are not well understood. To address this limitation, we performed gene network analyses using transcriptomic data from mice exposed during adolescence to Δ-9-tetrahydrocannabinol (THC), the major psychoactive component of cannabis. Methods: We injected vehicle or THC in female and male mice during the entire adolescence period. Two weeks following the last exposure, we measured recognition memory, social interaction and anxiety-related behaviors. We generated 120 RNA-seq datasets from 5 brain regions for each mouse. We performed differential gene expression analysis and constructed co-expression networks to identify THC-induced transcriptional alterations at the level of individual genes, gene networks, biological pathways, and cellular specificity. Further, we integrated THC-correlated gene networks with human traits from genome-wide association studies and performed key driver analysis to identify potential regulators of disorder-associated networks. Results: THC impaired cognitive behaviors of mice, with memory being more impacted in females, which coincided with larger transcriptional alterations in the female brain. Gene network analyses identified brain region-, cell type- and sex- specific co-expressed genes (“modules”) dysregulated by THC. THC-induced memory deficits in females were correlated with disruption of gene networks involved in endocannabinoid signaling and inflammation. Additional THC-correlated modules in both sexes involved converging pathways related to dopamine signaling and addiction processes. Moreover, the connectivity map of THC-correlated modules uncovered intra- and inter-region molecular circuitries influenced by THC. Further, modules altered by THC treatment were enriched in genes relevant for human cognition and schizophrenia. Conclusions: These findings provide novel insights concerning the genes, cell types, and pathways underlying persistent behavioral deficits induced by adolescent exposure to THC in a sex-specific manner, and highlight the connection between adolescent cannabis use and neuropsychiatric disorders in humans.
Project description:The objective of this study was to determine whether different milk treatments affected the genes related to cognitive function in the piglet's brain