Activated protein C and PAR1‐derived and PAR3‐derived peptides are anti‐inflammatory by suppressing macrophage NLRP3 inflammasomes. (7th December 2020)

• Record Type: Journal Article
• Authors: Healy, Laura D.; Fernández, José A.; Mosnier, Laurent O.; Griffin, John H.
• Is Part Of: Journal of thrombosis and haemostasis. Volume 19:Number 1(2021)
• Page Start: 269
• Page End: 280
• Publication Date: 2020-12-07
• Subjects: activated protein C -- caspase‐1 -- inflammasome -- NLRP3 inflammasome -- protease activated receptor; Thrombosis -- Periodicals; Hemostasis -- Periodicals; Blood coagulation disorders -- Periodicals; 616.1
• DOI: 10.1111/jth.15133
• Languages: English
• ISSNs: 1538-7933

Abstract

Abstract : Essentials Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective effects. We tested whether APC or non‐canonical PAR‐derived peptides suppress inflammasome activity. APC or PAR1‐ and PAR3‐derived peptides restrict inflammasome‐dependent caspase‐1 activity. Combined PAR1‐derived and PAR3‐derived peptides synergistically suppress caspase‐1 activity. Abstract: Background: Activated protein C (APC) has been shown to restrict murine inflammasome activity. However, whether APC can exert anti‐inflammatory activity in part through suppression of inflammasome activation in human systems is unknown. Objectives: Studies were made to determine whether either APC or protease activated receptor (PAR)‐derived peptides can reduce NLRP3 inflammasome activity in differentiated human THP‐1 macrophage‐like cells or in primary human monocytes stimulated to activate the inflammasome. Methods: Human THP‐1 cells or primary human monocytes were differentiated, treated with APC or PAR‐derived peptides, and then stimulated with lipopolysaccharide and ATP to induce caspase‐1 activity, a product of inflammasome activation. Results: Activated protein C or noncanonical PAR1‐derived or PAR3‐derived peptides significantly reduced caspase‐1 activity, detection of fluorescent NLRP3, and IL‐1β release from THP‐1 cells. At low concentrations where no effect was observed for each individual peptide, combinations of the PAR1‐derived peptide and the PAR3‐derived peptide resulted in a significant synergistic decrease in caspase‐1 and IL‐1β release. Caspase‐1 activity was also reduced in primary human monocytes. Studies using blocking antibodies and small molecule PAR1 inhibitors suggest that EPCR, PAR1, and PAR3 each play roles in the observed anti‐inflammatory effects. Several shortened versions of the PAR1‐ and PAR3‐derived peptide reduced caspase‐1 activity and exhibited synergistic anti‐inflammatory effects. Conclusions: The results indicate that both APC and certain PAR1‐ and PAR3‐derived peptides, which are biased agonists for PAR1 or PAR3, can reduce inflammasome activity in stimulated human monocytes as measured by caspase‐1 activity and IL‐1β release and that PAR‐derived biased peptide agonist combinations are synergistically anti‐inflammatory.