Modulation of GSK-3β activity in Venezuelan equine encephalitis virus infection

PLoS One. 2012;7(4):e34761. doi: 10.1371/journal.pone.0034761. Epub 2012 Apr 4.

Abstract

Alphaviruses, including Venezuelan Equine Encephalitis Virus (VEEV), cause disease in both equine and humans that exhibit overt encephalitis in a significant percentage of cases. Features of the host immune response and tissue-specific responses may contribute to fatal outcomes as well as the development of encephalitis. It has previously been shown that VEEV infection of mice induces transcription of pro-inflammatory cytokines genes (e.g., IFN-γ, IL-6, IL-12, iNOS and TNF-α) within 6 h. GSK-3β is a host protein that is known to modulate pro-inflammatory gene expression and has been a therapeutic target in neurodegenerative disorders such as Alzheimer's. Hence inhibition of GSK-3β in the context of encephalitic viral infections has been useful in a neuroprotective capacity. Small molecule GSK-3β inhibitors and GSK-3β siRNA experiments indicated that GSK-3β was important for VEEV replication. Thirty-eight second generation BIO derivatives were tested and BIOder was found to be the most potent inhibitor, with an IC(50) of ∼0.5 µM and a CC(50) of >100 µM. BIOder was a more potent inhibitor of GSK-3β than BIO, as demonstrated through in vitro kinase assays from uninfected and infected cells. Size exclusion chromatography experiments demonstrated that GSK-3β is found in three distinct complexes in VEEV infected cells, whereas GSK-3β is only present in one complex in uninfected cells. Cells treated with BIOder demonstrated an increase in the anti-apoptotic gene, survivin, and a decrease in the pro-apoptotic gene, BID, suggesting that modulation of pro- and anti-apoptotic genes contributes to the protective effect of BIOder treatment. Finally, BIOder partially protected mice from VEEV induced mortality. Our studies demonstrate the utility of GSK-3β inhibitors for modulating VEEV infection.

Publication types

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

MeSH terms

  • Animals
  • BH3 Interacting Domain Death Agonist Protein / analysis
  • Encephalitis Virus, Venezuelan Equine / drug effects*
  • Encephalomyelitis, Venezuelan Equine / drug therapy*
  • Encephalomyelitis, Venezuelan Equine / mortality
  • Enzyme Inhibitors / therapeutic use*
  • Female
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors*
  • Glycogen Synthase Kinase 3 beta
  • Inhibitor of Apoptosis Proteins / analysis
  • Mice
  • Mice, Inbred C3H
  • Repressor Proteins / analysis
  • Survivin
  • Virus Replication / drug effects

Substances

  • BH3 Interacting Domain Death Agonist Protein
  • Bid protein, mouse
  • Birc5 protein, mouse
  • Enzyme Inhibitors
  • Inhibitor of Apoptosis Proteins
  • Repressor Proteins
  • Survivin
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, mouse
  • Glycogen Synthase Kinase 3