Stressor-specific regulation of distinct brain-derived neurotrophic factor transcripts and cyclic AMP response element-binding protein expression in the postnatal and adult rat hippocampus

Neuropsychopharmacology. 2007 Jul;32(7):1504-19. doi: 10.1038/sj.npp.1301276. Epub 2006 Dec 13.

Abstract

Stress regulation of brain-derived neurotrophic factor (BDNF) is implicated in the hippocampal damage observed in depression. BDNF has a complex gene structure with four 5' untranslated exons (I-IV) with unique promoters, and a common 3' coding exon (V). To better understand the stress regulation of BDNF, we addressed whether distinct stressors differentially regulate exon-specific BDNF transcripts in the postnatal and adult hippocampus. The early life stress of maternal separation (MS) resulted in a time point-dependent differential upregulation of BDNF transcripts restricted to early postnatal life (P14-BDNF II, P21-BDNF IV, V). In adulthood, distinct stressors regulated BDNF transcripts in a signature manner. Immobilization stress, administered once, decreased all BDNF splice variants but had differing effects on BDNF I/II (increase) and III/IV (decrease) when administered chronically. Although immobilization stress reduced BDNF (V) mRNA, chronic unpredictable stress did not influence total BDNF despite altering specific BDNF transcripts. Furthermore, a prior history of MS altered the signature pattern in which adult-onset stress regulated specific BDNF transcripts. We also examined the expression of cyclic AMP response element-binding protein (CREB), an upstream transcriptional activator of BDNF, and observed a CREB induction in the postnatal hippocampus following MS. As a possible consequence of enhanced CREB and BDNF expression following MS, we examined hippocampal progenitor proliferation and observed a significant increase restricted to early life. These results suggest that alterations in CREB/BDNF may contribute to the generation of individual differences in stress neurocircuitry, providing a substrate for altered vulnerability to depressive disorders.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aging / physiology
  • Animals
  • Animals, Newborn
  • Brain-Derived Neurotrophic Factor / genetics*
  • Cell Differentiation / physiology
  • Cyclic AMP Response Element-Binding Protein / genetics*
  • Gene Expression Regulation, Developmental / genetics*
  • Hippocampus / growth & development*
  • Hippocampus / metabolism*
  • Male
  • Maternal Deprivation
  • Neural Pathways / growth & development
  • Neural Pathways / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Stem Cells / metabolism
  • Stress, Psychological / metabolism*
  • Stress, Psychological / physiopathology
  • Transcriptional Activation / physiology
  • Up-Regulation / physiology

Substances

  • Brain-Derived Neurotrophic Factor
  • Cyclic AMP Response Element-Binding Protein
  • RNA, Messenger