Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency

PLoS One. 2013 May 23;8(5):e63279. doi: 10.1371/journal.pone.0063279. Print 2013.

Abstract

Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CDC2 Protein Kinase / metabolism
  • Cattle
  • Cell Proliferation
  • Cell Size
  • Epithelial Cells / enzymology
  • Epithelial Cells / microbiology*
  • Epithelial Cells / physiology
  • G2 Phase Cell Cycle Checkpoints
  • HeLa Cells
  • Histones / metabolism
  • Host-Pathogen Interactions
  • Humans
  • Mitosis
  • Mitotic Index
  • Phosphorylation
  • Protein Processing, Post-Translational
  • Staphylococcus aureus / pathogenicity
  • Staphylococcus aureus / physiology*

Substances

  • Histones
  • CDC2 Protein Kinase

Grants and funding

Funding provided by a grant from the Animal Health Department of INRA. LA is the recipient of a fellowship from MRI INRA. SA is the recipient of a CAPES-COFECUB grant (Project 720/11). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.