Abstract
Stress profoundly impacts the brain and increases the risk of developing a psychiatric disorder. The brain’s response to stress is mediated by a number of pathways that affect gene expression and protein function throughout the cell. Understanding how stress achieves such dramatic effects on the brain requires an understanding of the brain’s stress response pathways. The majority of studies focused on molecular changes have employed repeated or chronic stress paradigms to assess the long-term consequences of stress and have not taken an integrative genomic and/or proteomic approach. Here, we determined the lasting impact of a single stressful event (restraint) on the broad molecular profile of the basolateral amygdala complex (BLC), a key brain region mediating emotion, memory and stress. Molecular profiling performed thirty days post-restraint consisted of small RNA sequencing, RNA sequencing and quantitative mass spectrometry and identified long-lasting changes in microRNA (miRNA), messenger RNA (mRNA) and proteins. Alignment of the three datasets further delineated the regulation of stress-specific pathways which were validated by qPCR and Western Blot analysis. From this analysis, mir-29a-5p was identified as a putative regulator of stress-induced adaptations in the BLC. Further, a number of predicted mir-29a-5p targets are regulated at the mRNA and protein level. The concerted and long-lasting disruption of multiple molecular pathways in the amygdala by a single stress event is expected to be sufficient to alter behavioral responses to a wide array of future experiences, including exposure to additional stressors.
Highlights
Stress from external stimuli induces an altered physiological response as the organism compensates to maintain a homeostatic balance [1]
We performed sequencing in two biological replicate cohorts (N = 3-4/group/cohort) and identified a miRNA profile that was significantly changed in both sequencing runs with a p-value of less than 0.05. 18 miRNAs were differentially expressed compared to naïve mice, with 3 upregulated and 15 downregulated (Fig 1B and Tables A-B in S1 File)
Four miRNAs were selected for qPCR validation in a set of technical replicates that included sequenced animals as well as an additional cohort of animals that were not sequenced as a set of biological replicates
Summary
Stress from external stimuli induces an altered physiological response as the organism compensates to maintain a homeostatic balance [1]. To achieve a systems level network view of stress-responsive pathways, RNA sequencing, RNA microarrays and quantitative proteomics have been performed independently on amygdala tissue after various forms of chronic stress [27, 28, 29] Such studies have highlighted the involvement of synaptic glutamate signaling in mediating plasticity of the amygdala after 8 weeks of chronic stress and identified networks of genes that are regulated at various timepoints after chronic social defeat, two paradigms that induce symptoms of major depressive disorder in rodents [28]. Non-neuronal networks may mediate stress responses, as two studies have identified astrocyte marker regulation and oligodendrocyte expression differences in stress paradigms [29, 31] While these findings demonstrate that stress induces significant changes in multiple molecular pathways in the amygdala, few studies of stress neurobiology have integrated miRNA datasets with RNA-sequencing [32, 33] and none have aligned small RNA sequencing of miRNAs with a corresponding proteomics profile. We highlight mir-29a-5p as a key stress-regulated miRNA that has many putative target pathways regulated in the opposite direction, suggesting that mir-29a-5p may modulate long-lasting neuroadaptations in the BLC after stressful experiences
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
