Prostaglandin D₂ is involved in the regulation of inflammatory response in Staphylococcus aureus-infected mice macrophages

Staphylococcus aureus (S. aureus) is one of the most infamous and widespread bacterial pathogens, causing a hard-to-estimate number of uncomplicated skin infections and probably hundreds of thousands to millions of more severe, invasive infections globally per year. S. aureus may also be acquired from animals, especially in the livestock industry. The interaction mechanism of host and S. aureus has significance for finding ways to against S. aureus infection and control inflammatory response of host, while the molecular biological activities after S. aureus infection, particular in inflammatory and immune cells are not fully clear. The present study aimed to explore whether pattern recognition receptors (PRRs) mediate prostaglandin D₂ (PGD₂) synthesis and PGD₂ participates in the regulation of inflammatory response in macrophages during S. aureus infection or synthetic bacterial lipopeptide (Pam2CSK4) stimulation. PGD₂ secretion level was enhanced by mice peritoneal macrophages infected with the S. aureus. The results indicated that PGD₂ secretion was impaired in S. aureus infected-macrophages from toll-like receptors 2 (TLR2)-deficient and NLR pyrin domain-containing 3 (NLRP3)-deficient mice. PGD₂ synthetase (hematopoietic PGD synthase, HPGDS) inhibitors could reduce the activation of macrophage mitogen-activated protein kinase (MAPK)/nuclear factor-κ-gene binding (NF-κB) signaling pathways. HPGDS inhibition impaired cytokines (TNF-α, IL-1β, IL-10 and RANTES) secretion and macrophage phagocytosis during S. aureus infection. In addition, inhibition of endogenous PGD₂ synthesis was unable to affect the TLR2 and NLRP3 expression in S. aureus-infected macrophages. Taken together, macrophage PGD₂ secretion after S. aureus infection depended on receptors TLR2 and NLRP3, and the induced PGD₂ participated in the regulation of inflammatory response in S. aureus-infected macrophages. Interestingly, it was found that exogenous PGD₂ down-regulated the cytokines secretion and had no effect on phagocytosis in the S. aureus-infected macrophages.