Fluoxetine signature on hippocampal MAPK signalling in sex-dependent manner

J Mol Neurosci. 2015 Feb;55(2):335-46. doi: 10.1007/s12031-014-0328-1. Epub 2014 May 21.

Abstract

A growing body of evidence indicates that mitogen-activated protein kinase (MAPK) participates in various stress-induced responses and is considered to be one of the pathophysiological mechanisms in depression. Surprisingly, the effect of antidepressants on MAPKs is almost unexplored, particularly from the perspective of sexes. The present study investigates the cytoplasm-nuclear distribution of MAPK family, c-Jun N-terminal kinases (JNKs) 1, 2 and 3; extracellular signal-regulated kinases (ERKs) 1 and 2; and p38 kinases, as well as their phosphoisoforms in the hippocampus of chronically stressed female and male rats and upon chronic fluoxetine treatment. Additionally, we analysed crosstalk between MAPK signalling and depressive-like behaviour which correlated with brain-derived neurotrophic factor (BDNF) expression. Our results emphasize a gender-specific and compartment-dependent response of MAPKs to stress and fluoxetine. In females, stress decreased pp38 and pJNK and induced cytosolic retention of pERKs which reduced all nuclear pMAPKs. These changes correlated with altered BDNF expression and behaviour. Similarly, in males, stress decreased pp38 but promoted nuclear translocation of pJNKs and pERKs. These stress alterations of pMAPKs in males were not associated with BDNF expression and depressive-like behaviour. Fluoxetine treatment in stressed females upregulated whole pMAPK signalling particularly those in nucleus which was followed with BDNF expression and normalization of behaviour. In stressed males, fluoxetine affected only cytosolic pJNKs, while nuclear pMAPK signalling and BDNF expression were unaffected even though fluoxetine normalized behaviour. Overall, our results suggest existence of gender-specific mechanism of fluoxetine on nuclear pMAPK/BDNF signalling and depressive-like behaviour and reinforce the antidepressant dogma that females and males respond differently to certain antidepressants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Antidepressive Agents, Second-Generation / pharmacology*
  • Antidepressive Agents, Second-Generation / therapeutic use
  • Brain-Derived Neurotrophic Factor / genetics
  • Brain-Derived Neurotrophic Factor / metabolism
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism
  • Female
  • Fluoxetine / pharmacology*
  • Fluoxetine / therapeutic use
  • Hippocampus / drug effects*
  • Hippocampus / metabolism
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • MAP Kinase Signaling System*
  • Male
  • Mitogen-Activated Protein Kinase Kinases / genetics
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Rats
  • Rats, Wistar
  • Sex Factors
  • Stress, Psychological / drug therapy
  • Stress, Psychological / metabolism*

Substances

  • Antidepressive Agents, Second-Generation
  • Brain-Derived Neurotrophic Factor
  • Isoenzymes
  • Fluoxetine
  • Mitogen-Activated Protein Kinase Kinases