Neurosteroid dehydroepiandrosterone exerts anti-apoptotic effects by membrane-mediated, integrated genomic and non-genomic pro-survival signaling pathways

J Neurochem. 2008 Dec;107(5):1457-69. doi: 10.1111/j.1471-4159.2008.05732.x.

Abstract

Dehydroepiandrosterone (DHEA) protects neural crest-derived PC12 cells from serum deprivation-induced apoptosis via G protein-associated specific plasma membrane-binding sites (mDBS). Here, we studied the signaling pathways involved in the pro-survival effects of DHEA-mediated activation of the mDBS binding sites. Membrane impermeable DHEA-bovine serum albumin (BSA) conjugate induced an acute phosphorylation of the prosurvival kinases Src, protein kinase A (PKA), MEK1/2/ERK1/2, and PI3K/Akt in serum deprived PC12 cells in parallel to an elevation of intracellular cAMP. The physiological significance of these findings was further assessed in a series of experiments using several selective pro-survival kinase inhibitors. Our combined findings suggest that the following sequence of events may take place following activation of mDBS binding sites: DHEA-BSA induces an acute but transient sequential phosphorylation of the pro-survival kinases Src/PKC(a/b)/MEK1/2/ERK1/2 which, in their turn, activate transcription factors cAMP responsive element binding protein and nuclear factor kappa B which induce the expression of the anti-apoptotic Bcl-2 genes. In parallel, DHEA-BSA increases intracellular cAMP, and the subsequent phosphorylation of PKA kinase and of cAMP responsive element binding protein. Finally, DHEA-BSA induces phosphorylation of PI3K/Akt kinases which, subsequently, lead to phosphorylation/deactivation of the pro-apoptotic Bad. Our findings suggest that the neurosteroid DHEA affects neural crest-derived cell survival by multiple pro-survival signaling pathways comprising an integrated system of non-genomic and genomic mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / pharmacology
  • Animals
  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Membrane / drug effects*
  • Cell Membrane / metabolism
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cell Survival / physiology
  • Cells, Cultured
  • Culture Media, Serum-Free / pharmacology
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Dehydroepiandrosterone / pharmacology*
  • Enzyme Inhibitors / pharmacology
  • Enzyme-Linked Immunosorbent Assay
  • Genomics
  • Hippocampus / cytology
  • Models, Biological
  • NF-kappa B / metabolism
  • PC12 Cells
  • Pertussis Toxin / pharmacology
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • src-Family Kinases / metabolism

Substances

  • Adjuvants, Immunologic
  • Culture Media, Serum-Free
  • Enzyme Inhibitors
  • NF-kappa B
  • Dehydroepiandrosterone
  • Cyclic AMP
  • Pertussis Toxin
  • Phosphatidylinositol 3-Kinases
  • src-Family Kinases
  • Cyclic AMP-Dependent Protein Kinases