Ca2+ influx and tyrosine kinases trigger Bordetella adenylate cyclase toxin (ACT) endocytosis. Cell physiology and expression of the CD11b/CD18 integrin major determinants of the entry route

PLoS One. 2013 Sep 13;8(9):e74248. doi: 10.1371/journal.pone.0074248. eCollection 2013.

Abstract

Humans infected with Bordetella pertussis, the whooping cough bacterium, show evidences of impaired host defenses. This pathogenic bacterium produces a unique adenylate cyclase toxin (ACT) which enters human phagocytes and catalyzes the unregulated formation of cAMP, hampering important bactericidal functions of these immune cells that eventually cause cell death by apoptosis and/or necrosis. Additionally, ACT permeabilizes cells through pore formation in the target cell membrane. Recently, we demonstrated that ACT is internalised into macrophages together with other membrane components, such as the integrin CD11b/CD18 (CR3), its receptor in these immune cells, and GM1. The goal of this study was to determine whether ACT uptake is restricted to receptor-bearing macrophages or on the contrary may also take place into cells devoid of receptor and gain more insights on the signalling involved. Here, we show that ACT is rapidly eliminated from the cell membrane of either CR3-positive as negative cells, though through different entry routes, which depends in part, on the target cell physiology and characteristics. ACT-induced Ca(2+) influx and activation of non-receptor Tyr kinases into the target cell appear to be common master denominators in the different endocytic strategies activated by this toxin. Very importantly, we show that, upon incubation with ACT, target cells are capable of repairing the cell membrane, which suggests the mounting of an anti-toxin cell repair-response, very likely involving the toxin elimination from the cell surface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylate Cyclase Toxin / isolation & purification
  • Adenylate Cyclase Toxin / metabolism
  • Adenylate Cyclase Toxin / pharmacology*
  • Animals
  • Bordetella pertussis / chemistry*
  • Bordetella pertussis / metabolism
  • CD11b Antigen / genetics*
  • CD11b Antigen / metabolism
  • CD18 Antigens / genetics*
  • CD18 Antigens / metabolism
  • CHO Cells
  • Calcium / metabolism*
  • Cell Membrane / metabolism
  • Cricetulus
  • Cyclic AMP / metabolism
  • Endocytosis
  • Gene Expression Regulation
  • Host-Pathogen Interactions
  • Humans
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Mice
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / pharmacology*
  • Signal Transduction
  • src-Family Kinases / genetics*
  • src-Family Kinases / metabolism

Substances

  • Adenylate Cyclase Toxin
  • CD11b Antigen
  • CD18 Antigens
  • Recombinant Proteins
  • Cyclic AMP
  • src-Family Kinases
  • Calcium

Grants and funding

This study was supported by grants from the Spanish Ministerio de Ciencia y Tecnología (Project BFU 2007-62062 and Project BFU 2012-36241), the Basque Government (ETORTEK Program), and the University of Basque Country (UPV/EHU, Project UE06/10). KBU and GG were recipients of a fellowship from the Bizkaia Biophysics Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.