Staphylococcus aureus alpha-toxin mediates general and cell type-specific changes in metabolite concentrations of immortalized human airway epithelial cells

PLoS One. 2014 Apr 14;9(4):e94818. doi: 10.1371/journal.pone.0094818. eCollection 2014.

Abstract

Staphylococcus aureus alpha-toxin (Hla) is a potent pore-forming cytotoxin that plays an important role in the pathogenesis of S. aureus infections, including pneumonia. The impact of Hla on the dynamics of the metabolome in eukaryotic host cells has not been investigated comprehensively. Using 1H-NMR, GC-MS and HPLC-MS, we quantified the concentrations of 51 intracellular metabolites and assessed alterations in the amount of 25 extracellular metabolites in the two human bronchial epithelial cell lines S9 and 16HBE14o- under standard culture conditions and after treatment with sub-lethal amounts (2 µg/ml) of recombinant Hla (rHla) in a time-dependent manner. Treatment of cells with rHla caused substantial decreases in the concentrations of intracellular metabolites from different metabolic pathways in both cell lines, including ATP and amino acids. Concomitant increases in the extracellular concentrations were detected for various intracellular compounds, including nucleotides, glutathione disulfide and NAD+. Our results indicate that rHla has a major impact on the metabolome of eukaryotic cells as a consequence of direct rHla-mediated alterations in plasma membrane permeability or indirect effects mediated by cellular signalling. However, cell-specific changes also were observed. Glucose consumption and lactate production rates suggest that the glycolytic activity of S9 cells, but not of 16HBE14o- cells, is increased in response to rHla. This could contribute to the observed higher level of resistance of S9 cells against rHla-induced membrane damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Toxins / toxicity*
  • Bronchi / cytology*
  • Cell Line, Transformed
  • Cell Survival / drug effects
  • Citric Acid Cycle / drug effects
  • Epithelial Cells / cytology*
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism*
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • Glucose / metabolism
  • Glutamine / metabolism
  • Glycolysis / drug effects
  • Hemolysin Proteins / toxicity*
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism
  • Lactates / metabolism
  • Metabolomics
  • Nucleotides / metabolism
  • Principal Component Analysis
  • Recombinant Proteins / toxicity

Substances

  • Bacterial Toxins
  • Hemolysin Proteins
  • Lactates
  • Nucleotides
  • Recombinant Proteins
  • staphylococcal alpha-toxin
  • Glutamine
  • Glucose

Grants and funding

This study was supported by funds from the Bundesminesterium für Bildung und Forschung (http://www.unternehmen-region.de/) to FH (03Z1CN21) and the Deutsche Forschungsgemeinschaft (http://www.dfg.de/) - SFB/TRR34 to PG, ML (Project Z4) and JPH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.