Isoform switching of steroid receptor co-activator-1 attenuates glucocorticoid-induced anxiogenic amygdala CRH expression

Mol Psychiatry. 2016 Dec;21(12):1733-1739. doi: 10.1038/mp.2016.16. Epub 2016 Mar 15.

Abstract

Maladaptive glucocorticoid effects contribute to stress-related psychopathology. The glucocorticoid receptor (GR) that mediates many of these effects uses multiple signaling pathways. We have tested the hypothesis that manipulation of downstream factors ('coregulators') can abrogate potentially maladaptive GR-mediated effects on fear-motivated behavior that are linked to corticotropin releasing hormone (CRH). For this purpose the expression ratio of two splice variants of steroid receptor coactivator-1 (SRC-1) was altered via antisense-mediated 'exon-skipping' in the central amygdala of the mouse brain. We observed that a change in splicing towards the repressive isoform SRC-1a strongly reduced glucocorticoid-induced responsiveness of Crh mRNA expression and increased methylation of the Crh promoter. The transcriptional GR target gene Fkbp5 remained responsive to glucocorticoids, indicating gene specificity of the effect. The shift of the SRC-1 splice variants altered glucocorticoid-dependent exploratory behavior and attenuated consolidation of contextual fear memory. In conclusion, our findings demonstrate that manipulation of GR signaling pathways related to the Crh gene can selectively diminish potentially maladaptive effects of glucocorticoids.

MeSH terms

  • Alternative Splicing
  • Amygdala
  • Animals
  • Corticosterone / metabolism
  • Corticotropin-Releasing Hormone / metabolism*
  • Fear
  • Gene Expression Regulation / drug effects
  • Glucocorticoids / metabolism
  • Mice
  • Nuclear Receptor Coactivator 1 / genetics
  • Nuclear Receptor Coactivator 1 / metabolism*
  • Promoter Regions, Genetic / drug effects
  • Protein Isoforms / genetics
  • RNA Isoforms
  • RNA, Messenger / metabolism
  • Receptors, Glucocorticoid / metabolism
  • Receptors, Steroid
  • Tacrolimus Binding Proteins / metabolism

Substances

  • Glucocorticoids
  • Protein Isoforms
  • RNA Isoforms
  • RNA, Messenger
  • Receptors, Glucocorticoid
  • Receptors, Steroid
  • Corticotropin-Releasing Hormone
  • Ncoa1 protein, mouse
  • Nuclear Receptor Coactivator 1
  • Tacrolimus Binding Proteins
  • tacrolimus binding protein 5
  • Corticosterone