Transcriptomic profiles of susceptibility and resilience to stress in the amygdala and hippocampus of male rats

Abstract

Traumatic experiences elicit a wide range of cognitive responses in both humans and animals, leading to diverse outcomes such as enhanced performance, cognitive impairment, or the development of mood and anxiety disorders like posttraumatic stress disorder (PTSD). A key challenge in understanding these varied responses is to decipher the underlying biological mechanisms that contribute to individual variability in trauma resilience or susceptibility. The purpose of this study was to elucidate the molecular bases for these differences, focusing on the amygdala and hippocampus—brain regions integral to stress responses. We exposed adult, male rats to an acute, severe stressor and profiled persistent anxiety-like behavior outcomes 7 days later. We investigated the transcriptional signatures in the basolateral amygdala and hippocampal dentate gyrus via bulk RNA sequencing from animals with behavioral outcomes indicative of stress resilience or vulnerability. Our results suggest that the basolateral amygdala and dentate gyrus display distinct transcriptomic changes following acute, severe stress. Furthermore, we identified specific region-dependent genes related to insulin signaling, neural plasticity, and stress responses that correlate with resilient and vulnerable phenotypes. Notably, a larger number of genes separated stress-resilient animals from both control and stress-susceptible animals, underscoring that an active molecular response, particularly in the hippocampus, facilitates protection from the long-term consequences of severe stress. These findings provide novel insight into the mechanisms that engender individual variability in the behavioral responses to stress and offer new targets for the advancement of therapies for stress-induced neuropsychiatric disorders.