Convergence of alpha 7 nicotinic acetylcholine receptor-activated pathways for anti-apoptosis and anti-inflammation: central role for JAK2 activation of STAT3 and NF-kappaB

Brain Res. 2009 Feb 23:1256:1-7. doi: 10.1016/j.brainres.2008.11.053. Epub 2008 Nov 27.

Abstract

Our laboratories have previously identified the alpha7 nAChR-JAK2 pathway as playing a central role in nicotine-induced neuroprotection. We have also reported that the angiotensin II (Ang II) AT(2) receptor induced activation of SHP-1 induces the tyrosine dephosphorylation of JAK2 that results in a complete neutralization of the alpha7 nAChR-JAK2 pro-survival cascade. In this study, we investigated the effects of inhibiting the alpha7 nAChR-JAK2 pro-survival cascade on the nicotine-induced production of the survival factor Bcl-2 and the transcriptional activation of NF-kappaB, AP-1, STAT1, STAT3, and STAT5. We report that nicotine induced the production of Bcl-2 and increased the transcriptional activation of NF-kappaB, AP-1, STAT1, and STAT3, and with the exception of AP-1, the other transcription factors (NF-kappaB, STAT1, and STAT3) were significantly reduced by JAK2 inhibition. We also demonstrate that, via transfection of either Bcl-2 antisense or NF-kappaB, STAT1 and STAT3 transcription factor decoys oligodeoxyribonucleotides into PC12 cells, nicotine induces its neuroprotection in PC12 cells via activation of the alpha7 nAChR-JAK2-(NF-kappaB; STAT3)-Bcl-2 pro-survival pathway. Finally, the neuroprotective nicotine-induced production of Bcl-2 appears to fully counteract the Abeta (1-42)-induced apoptosis of PC12 cells by blocking Abeta (1-42)-induced mitochondrial release of cytosolic cytochrome C.

MeSH terms

  • Amyloid beta-Peptides / metabolism
  • Animals
  • Apoptosis*
  • Cytochromes c / metabolism
  • Enzyme Activation
  • Gene Expression
  • Inflammation / physiopathology*
  • Janus Kinase 2 / antagonists & inhibitors
  • Janus Kinase 2 / metabolism*
  • Mitochondria / physiology
  • NF-kappa B / metabolism*
  • Neuroprotective Agents / pharmacology
  • Nicotine / pharmacology
  • PC12 Cells
  • Peptide Fragments / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats
  • Receptors, Nicotinic / physiology*
  • STAT1 Transcription Factor / metabolism
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction*
  • Transcription Factor AP-1 / metabolism
  • Tyrphostins / pharmacology
  • alpha7 Nicotinic Acetylcholine Receptor

Substances

  • Amyloid beta-Peptides
  • Chrna7 protein, rat
  • NF-kappa B
  • Neuroprotective Agents
  • Peptide Fragments
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Nicotinic
  • STAT1 Transcription Factor
  • STAT3 Transcription Factor
  • Stat1 protein, rat
  • Stat3 protein, rat
  • Transcription Factor AP-1
  • Tyrphostins
  • alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide
  • alpha7 Nicotinic Acetylcholine Receptor
  • amyloid beta-protein (1-42)
  • Nicotine
  • Cytochromes c
  • Jak2 protein, rat
  • Janus Kinase 2