Cytosolic Phospholipase A2α Promotes Pulmonary Inflammation and Systemic Disease during Streptococcus pneumoniae Infection

Infect Immun. 2017 Oct 18;85(11):e00280-17. doi: 10.1128/IAI.00280-17. Print 2017 Nov.

Abstract

Pulmonary infection by Streptococcus pneumoniae is characterized by a robust alveolar infiltration of neutrophils (polymorphonuclear cells [PMNs]) that can promote systemic spread of the infection if not resolved. We previously showed that 12-lipoxygenase (12-LOX), which is required to generate the PMN chemoattractant hepoxilin A3 (HXA3) from arachidonic acid (AA), promotes acute pulmonary inflammation and systemic infection after lung challenge with S. pneumoniae As phospholipase A2 (PLA2) promotes the release of AA, we investigated the role of PLA2 in local and systemic disease during S. pneumoniae infection. The group IVA cytosolic isoform of PLA2 (cPLA2α) was activated upon S. pneumoniae infection of cultured lung epithelial cells and was critical for AA release from membrane phospholipids. Pharmacological inhibition of this enzyme blocked S. pneumoniae-induced PMN transepithelial migration in vitro Genetic ablation of the cPLA2 isoform cPLA2α dramatically reduced lung inflammation in mice upon high-dose pulmonary challenge with S. pneumoniae The cPLA2α-deficient mice also suffered no bacteremia and survived a pulmonary challenge that was lethal to wild-type mice. Our data suggest that cPLA2α plays a crucial role in eliciting pulmonary inflammation during pneumococcal infection and is required for lethal systemic infection following S. pneumoniae lung challenge.

Keywords: Streptococcus pneumoniae; inflammation; neutrophils; phospholipase.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonic Acid / immunology
  • Arachidonic Acid / metabolism
  • Bacteremia / genetics
  • Bacteremia / immunology
  • Bacteremia / prevention & control
  • Cell Line, Tumor
  • Chemotactic Factors / immunology
  • Chemotactic Factors / metabolism
  • Chlorobenzoates / pharmacology
  • Cinnamates / pharmacology
  • Cyclohexanones / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Epithelial Cells / drug effects
  • Epithelial Cells / enzymology
  • Epithelial Cells / immunology*
  • Epithelial Cells / microbiology
  • Group IV Phospholipases A2 / antagonists & inhibitors
  • Group IV Phospholipases A2 / deficiency
  • Group IV Phospholipases A2 / genetics
  • Group IV Phospholipases A2 / immunology*
  • Host-Pathogen Interactions*
  • Humans
  • Lung / drug effects
  • Lung / enzymology
  • Lung / immunology*
  • Lung / microbiology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Knockout
  • Neutrophil Infiltration / drug effects
  • Neutrophils / drug effects
  • Neutrophils / immunology
  • Neutrophils / microbiology
  • Pneumococcal Infections / genetics
  • Pneumococcal Infections / immunology*
  • Pneumococcal Infections / microbiology
  • Pneumococcal Infections / mortality
  • Pneumonia, Bacterial / genetics
  • Pneumonia, Bacterial / immunology*
  • Pneumonia, Bacterial / microbiology
  • Pneumonia, Bacterial / mortality
  • Streptococcus pneumoniae / drug effects
  • Streptococcus pneumoniae / genetics
  • Streptococcus pneumoniae / pathogenicity
  • Survival Analysis
  • Transendothelial and Transepithelial Migration / drug effects
  • Transendothelial and Transepithelial Migration / immunology
  • ortho-Aminobenzoates / pharmacology

Substances

  • Chemotactic Factors
  • Chlorobenzoates
  • Cinnamates
  • Cyclohexanones
  • Enzyme Inhibitors
  • ortho-Aminobenzoates
  • 4-amylcinnamoylanthranilic acid
  • Arachidonic Acid
  • 1,6-bis(cyclohexyloximinocarbonyl)hexane
  • 2-(4-amylcinnamoyl)amino-4-chlorobenzoic acid
  • Group IV Phospholipases A2