Functional and structural consequences of epithelial cell invasion by Bordetella pertussis adenylate cyclase toxin

PLoS One. 2020 May 11;15(5):e0228606. doi: 10.1371/journal.pone.0228606. eCollection 2020.

Abstract

Bordetella pertussis, the causative agent of whopping cough, produces an adenylate cyclase toxin (CyaA) that plays a key role in the host colonization by targeting innate immune cells which express CD11b/CD18, the cellular receptor of CyaA. CyaA is also able to invade non-phagocytic cells, via a unique entry pathway consisting in a direct translocation of its catalytic domain across the cytoplasmic membrane of the cells. Within the cells, CyaA is activated by calmodulin to produce high levels of cyclic adenosine monophosphate (cAMP) and alter cellular physiology. In this study, we explored the effects of CyaA toxin on the cellular and molecular structure remodeling of A549 alveolar epithelial cells. Using classical imaging techniques, biochemical and functional tests, as well as advanced cell mechanics method, we quantify the structural and functional consequences of the massive increase of intracellular cyclic AMP induced by the toxin: cell shape rounding associated to adhesion weakening process, actin structure remodeling for the cortical and dense components, increase in cytoskeleton stiffness, and inhibition of migration and repair. We also show that, at low concentrations (0.5 nM), CyaA could significantly impair the migration and wound healing capacities of the intoxicated alveolar epithelial cells. As such concentrations might be reached locally during B. pertussis infection, our results suggest that the CyaA, beyond its major role in disabling innate immune cells, might also contribute to the local alteration of the epithelial barrier of the respiratory tract, a hallmark of pertussis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylate Cyclase Toxin / genetics*
  • Adenylate Cyclase Toxin / metabolism
  • Bordetella pertussis / enzymology*
  • Bordetella pertussis / pathogenicity
  • Calmodulin / metabolism
  • Cell Membrane / metabolism
  • Cyclic AMP / genetics
  • Epithelial Cells / microbiology
  • Humans
  • Immunity, Innate / genetics*
  • Respiratory System / metabolism
  • Respiratory System / microbiology
  • Respiratory System / pathology
  • Whooping Cough / genetics*
  • Whooping Cough / microbiology
  • Whooping Cough / pathology

Substances

  • Adenylate Cyclase Toxin
  • Calmodulin
  • Cyclic AMP

Grants and funding

DI: grant number DBS20140930771 Fondation pour la Recherche Médicale http://www.frm.org The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.