Protease-Activated Receptor 2 Facilitates Bacterial Dissemination in Pneumococcal Pneumonia

J Infect Dis. 2018 Apr 11;217(9):1462-1471. doi: 10.1093/infdis/jiy010.

Abstract

Streptococcus pneumoniae is the most common causative pathogen in community-acquired pneumonia. Protease-activated receptor 2 (PAR2) is expressed by different cell types in the lungs and can mediate inflammatory responses. We sought to determine the role of PAR2 during pneumococcal pneumonia. Pneumococcal pneumonia or sepsis was induced in wild-type and PAR2 knock-out (Par2-/-) mice by infection with viable S. pneumoniae. Par2-/- mice demonstrated improved host defense, a largely preserved lung barrier integrity, and reduced mortality during pneumococcal pneumonia. PAR2 deficiency did not influence bacterial growth after intravenous infection. Inhibition of the endogenous PAR2 activating proteases tissue factor/factor VIIa or tryptase did not impact on bacterial burdens during pneumonia. In a PAR2 reporter cell line it was demonstrated that S. pneumoniae-derived proteases are able to cleave PAR2. These results show that S. pneumoniae is able to cleave and exploit PAR2 to disseminate systemically from the airways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Load
  • Blood Coagulation
  • Gene Expression Regulation / drug effects
  • HEK293 Cells
  • Helminth Proteins / pharmacology
  • Humans
  • Inflammation
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Pneumonia, Pneumococcal / microbiology*
  • Pneumonia, Pneumococcal / pathology
  • Receptor, PAR-2*
  • Specific Pathogen-Free Organisms
  • Streptococcus pneumoniae / physiology*

Substances

  • Helminth Proteins
  • Receptor, PAR-2
  • anti-coagulant protein C2, Ancylostoma caninum