Transcriptome Dynamics in Mouse Amygdala under Acute and Chronic Stress Revealed by Thio-labeled RNA Sequencing

Abstract

Both acute and chronic stress have significant impact on brain functions. The amygdala is essential in mediating stress responses, but how its transcriptomic dynamics change under stress remains elusive. To overcome the difficulties in detecting subtle stress-induced changes by evaluating total RNA using classic RNA sequencing, we conducted thiol-labeled RNA sequencing (SLAM-seq). We injected 4-thiouridine (4sU) into mouse amygdala followed by SLAM-seq to detect nascent mRNA induced by acute and chronic restraint stress, and found that SLAM-seq could label actively transcribed genes in the major neuronal and glial subtypes. We also found that acute stress induced active transcription of 6 gamma-aminobutyric acid (GABA) receptors and only 1 glutamate receptor, indicating an imminent increase of inhibitory control in the stressed amygdala. Conversely, chronic stress led to active transcription of 3 glutamate receptors and 4 GABA receptors, suggesting a release of inhibitory control and hyperactivity of the amygdala. SLAM-seq also identified genes associated with myelination under chronic stress, and this finding is confirmed by immunostaining showing increased myelination in chronically stressed amygdala. Additionally, genes detected by SLAM-seq and RNA-seq only partially overlapped, with SLAM-seq particularly sensitive to transcriptional changes in genes with high basal transcription levels. Thus, by applying SLAM-seq in vivo, we obtained a rich dataset of nascently transcribed genes in the amygdala under stress, and revealed distinct transcriptional dynamics associated with acute and chronic stress.