S. aureus alpha-toxin monomer binding and heptamer formation in host cell membranes - Do they determine sensitivity of airway epithelial cells toward the toxin?

PLoS One. 2020 May 29;15(5):e0233854. doi: 10.1371/journal.pone.0233854. eCollection 2020.

Abstract

Alpha-toxin (Hla) is a major virulence factor of Staphylococcus aureus (S. aureus) and plays an important role in S. aureus-induced pneumonia. It binds as a monomer to the cell surface of eukaryotic host cells and forms heptameric transmembrane pores. Sensitivities toward the toxin of various types of potential host cells have been shown to vary substantially, and the reasons for these differences are unclear. We used three human model airway epithelial cell lines (16HBE14o-, S9, A549) to correlate cell sensitivity (measured as rate of paracellular gap formation in the cell layers) with Hla monomer binding, presence of the potential Hla receptors ADAM10 or α5β1 integrin, presence of the toxin-stabilizing factor caveolin-1 as well as plasma membrane lipid composition (phosphatidylserine/choline, sphingomyelin). The abundance of ADAM10 correlated best with gap formation or cell sensitivities, respectively, when the three cell types were compared. Caveolin-1 or α5β1 integrin did not correlate with toxin sensitivity. The relative abundance of sphingomyelin in plasma membranes may also be used as a proxi for cellular sensitivity against alpha-toxin as sphingomyelin abundances correlated well with the intensities of alpha-toxin mediated gap formation in the cell layers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Bacterial Toxins / metabolism*
  • Bacterial Toxins / toxicity*
  • Caveolin 1 / metabolism
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism*
  • Cell Size
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism*
  • Hemolysin Proteins / metabolism*
  • Hemolysin Proteins / toxicity*
  • Host-Pathogen Interactions* / drug effects
  • Humans
  • Models, Biological
  • Phospholipids / metabolism
  • Protein Binding
  • Receptors, Cell Surface / metabolism
  • Respiratory System / pathology*

Substances

  • Bacterial Toxins
  • Caveolin 1
  • Hemolysin Proteins
  • Phospholipids
  • Receptors, Cell Surface
  • staphylococcal alpha-toxin

Grants and funding

We acknowledge support for the Article Processing Charge from the DFG (German Research Foundation, 393148499) and the Open Access Publication Fund of the University of Greifswald. Nils Möller is the recipient of a graduate student stipend of the State of Mecklenburg-Vorpommern, Germany. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.