Infect Immun. 2017 Aug 14. pii: IAI.00280-17. doi: 10.1128/IAI.00280-17. [Epub ahead of print]
Pulmonary infection by Streptococcus pneumoniae is characterized by a robust alveolar infiltration of neutrophils (polymorphonuclear cells or 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. pneumoniaelung challenge.
Copyright © 2017 American Society for Microbiology.
PMID: 28808157 DOI: 10.1128/IAI.00280-17