Staphylococcus aureus Adenosine Inhibits sPLA2-IIA-Mediated Host Killing in the Airways

• Published in: The Journal of immunology (1950) 2015-06, Vol.194 (11), p.5312-5319
• Main Authors: Pernet, Erwan, Brunet, Jérémy, Guillemot, Laurent, Chignard, Michel, Touqui, Lhousseine, Wu, Yongzheng
• Format: Article
• Language: English
• Subjects: Adenosine; Adenosine - genetics; Adenosine - immunology; Animals; Bacteriology; Bronchoalveolar Lavage Fluid; Cell Line; CHO Cells; Cricetinae; Cricetulus; Cyclic AMP-Dependent Protein Kinases; Cyclic AMP-Dependent Protein Kinases - metabolism; Group II Phospholipases A2; Group II Phospholipases A2 - antagonists & inhibitors; Group II Phospholipases A2 - biosynthesis; Guinea Pigs; Host-Pathogen Interactions; Imidazoles; Imidazoles - pharmacology; Immunology; Innate immunity; Life Sciences; Macrophages, Alveolar; Macrophages, Alveolar - immunology; Male; Microbiology and Parasitology; NF-kappa B; NF-kappa B - metabolism; Nod2 Signaling Adaptor Protein; Nod2 Signaling Adaptor Protein - immunology; p38 Mitogen-Activated Protein Kinases; p38 Mitogen-Activated Protein Kinases - antagonists & inhibitors; p38 Mitogen-Activated Protein Kinases - metabolism; Phagocytosis; Phagocytosis - immunology; Phosphorylation; Pyridines; Pyridines - pharmacology; Receptor, Adenosine A2A; Receptor, Adenosine A2A - metabolism; Receptor, Adenosine A2B; Receptor, Adenosine A2B - metabolism; Staphylococcal Infections; Staphylococcal Infections - immunology; Staphylococcal Infections - microbiology; Staphylococcus aureus; Staphylococcus aureus - genetics; Staphylococcus aureus - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1402665

Staphylococcus aureus is a common cause of bacterial infections in respiratory diseases. It secretes molecules to dampen host immunity, and the recently identified adenosine is one of these molecules. The type IIA secretory phospholipase A2 (sPLA2-IIA) is a host protein endowed with antibacterial properties, especially against Gram-positive bacteria such as S. aureus. However, the role of adenosine in sPLA2-IIA-mediated S. aureus killing by host is still unknown. The present studies showed that the S. aureus mutant lacking adenosine production (∆adsA strain) increased sPLA2-IIA expression in guinea pig airways and was cleared more efficiently, compared with the wild-type strain. S. aureus ∆adsA strain induced sPLA2-IIA expression by alveolar macrophages after phagocytic process via NOD2-NF-κB-dependent mechanism. However, S. aureus adenosine (wild-type and adsA-complemented strains) and exogenous adenosine downregulated S. aureus phagocytosis by alveolar macrophages, leading to inhibition of sPLA2-IIA expression. This occurred through inhibition of p38 phosphorylation via adenosine receptors A2a-, A2b-, and protein kinase A-dependent pathways. Taken together, our studies suggest that, in the airway, S. aureus escapes sPLA2-IIA-mediated killing through adenosine-mediated inhibition of phagocytosis and sPLA2-IIA expression.