Map kinase and PKC signaling pathways modulate NGF-mediated apoE transcription

Neurosci Lett. 2015 May 19:595:54-9. doi: 10.1016/j.neulet.2015.03.032. Epub 2015 Mar 19.

Abstract

The present study assessed the mechanisms by which nerve growth factor (NGF) increased the level of apolipoprotein E (apoE) in PC12 cells. NGF (50ng/mL) significantly increased apoE protein levels following 72h of treatment. Similarly NGF increased luciferase activity in cells transfected with a luciferase reporter construct containing a 500bp fragment of the apoE promoter, indicating NGF-induced apoE expression is regulated, at least in part, at the level of transcription. The non-selective nitric oxide synthase (NOS) inhibitor N(ɷ)-nitro-L-arginine methylester (L-NAME; 20mM) did not attenuate the NGF-mediated increase in luciferase activity, while the inducible NOS inhibitor s-methylisothiourea (S-MIU; 2mM) partially attenuated this action of NGF. Inhibition of MAP kinase activation with 50μM U0126 or pre-treatment with the PKC inhibitor bisindolylmaleimide 1 (BIS-1; 10μM) prevented the NGF-mediated activation of the apoE promoter. Pre-treatment with the phospholipase C (PLC) inhibitor U73122 (5μM) partially inhibited the NGF-induced increase in luciferase activity while the Akt inhibitor LY294002 (10μM) had no effect. These data suggest NGF-induced apoE transcription requires MAP kinase and PKC activation and that these TrkA signaling pathways may be modulated by NO.

Keywords: Apolipoprotein E (apoE); Nerve growth factor (NGF); Nitric oxide (NO); PC12 cells; Signal transduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apolipoproteins E / genetics*
  • Apolipoproteins E / metabolism
  • Chromones / pharmacology
  • Estrenes / pharmacology
  • Indoles / pharmacology
  • Isothiuronium / analogs & derivatives
  • Isothiuronium / pharmacology
  • Maleimides / pharmacology
  • Mitogen-Activated Protein Kinases / metabolism*
  • Morpholines / pharmacology
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Nerve Growth Factor / metabolism*
  • Nerve Growth Factor / pharmacology
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • Nitric Oxide Synthase Type II / metabolism
  • PC12 Cells
  • Promoter Regions, Genetic
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Pyrrolidinones / pharmacology
  • Rats
  • Signal Transduction
  • Transcription, Genetic
  • Type C Phospholipases / antagonists & inhibitors

Substances

  • Apolipoproteins E
  • Chromones
  • Estrenes
  • Indoles
  • Maleimides
  • Morpholines
  • Pyrrolidinones
  • 1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
  • Isothiuronium
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Nerve Growth Factor
  • Nitric Oxide Synthase Type II
  • Proto-Oncogene Proteins c-akt
  • Protein Kinase C
  • Mitogen-Activated Protein Kinases
  • Type C Phospholipases
  • S-methylisothiopseudouronium
  • bisindolylmaleimide
  • NG-Nitroarginine Methyl Ester