Reverse-phase phosphoproteome analysis of signaling pathways induced by Rift valley fever virus in human small airway epithelial cells

PLoS One. 2010 Nov 3;5(11):e13805. doi: 10.1371/journal.pone.0013805.

Abstract

Rift valley fever virus (RVFV) infection is an emerging zoonotic disease endemic in many countries of sub-Saharan Africa and in Egypt. In this study we show that human small airway epithelial cells are highly susceptible to RVFV virulent strain ZH-501 and the attenuated strain MP-12. We used the reverse-phase protein arrays technology to identify phosphoprotein signaling pathways modulated during infection of cultured airway epithelium. ZH-501 infection induced activation of MAP kinases (p38, JNK and ERK) and downstream transcriptional factors [STAT1 (Y701), ATF2 (T69/71), MSK1 (S360) and CREB (S133)]. NF-κB phosphorylation was also increased. Activation of p53 (S15, S46) correlated with the increased levels of cleaved effector caspase-3, -6 and -7, indicating activation of the extrinsic apoptotic pathway. RVFV infection downregulated phosphorylation of a major anti-apoptotic regulator of survival pathways, AKT (S473), along with phosphorylation of FOX 01/03 (T24/31) which controls cell cycle arrest downstream from AKT. Consistent with this, the level of apoptosis inhibitor XIAP was decreased. However, the intrinsic apoptotic pathway marker, caspase-9, demonstrated only a marginal activation accompanied by an increased level of the inhibitor of apoptosome formation, HSP27. Concentration of the autophagy marker, LC3B, which often accompanies the pro-survival signaling, was decreased. Cumulatively, our analysis of RVFV infection in lung epithelium indicated a viral strategy directed toward the control of cell apoptosis through a number of transcriptional factors. Analyses of MP-12 titers in challenged cells in the presence of MAPK inhibitors indicated that activation of p38 represents a protective cell response while ERK activation controls viral replication.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Blotting, Western
  • Caspases / metabolism
  • Cells, Cultured
  • Child
  • Epithelial Cells / metabolism*
  • Epithelial Cells / virology*
  • Female
  • HSP27 Heat-Shock Proteins / metabolism
  • Host-Pathogen Interactions
  • Humans
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphoproteins / analysis*
  • Phosphoproteins / metabolism
  • Proteome / analysis*
  • Proteome / metabolism
  • Proteomics / methods
  • Proto-Oncogene Proteins c-akt / metabolism
  • Respiratory System / cytology
  • Rift Valley Fever / virology
  • Rift Valley fever virus / isolation & purification
  • Rift Valley fever virus / physiology*
  • Signal Transduction*
  • Transcription Factors / metabolism
  • X-Linked Inhibitor of Apoptosis Protein / metabolism

Substances

  • HSP27 Heat-Shock Proteins
  • Phosphoproteins
  • Proteome
  • Transcription Factors
  • X-Linked Inhibitor of Apoptosis Protein
  • XIAP protein, human
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinases
  • Caspases