[HTML][HTML] Caspase-1–mediated pathway promotes generation of thromboinflammatory microparticles

AS Rothmeier, P Marchese, BG Petrich… - The Journal of …, 2015 - Am Soc Clin Investig
AS Rothmeier, P Marchese, BG Petrich, C Furlan-Freguia, MH Ginsberg, ZM Ruggeri, W Ruf
The Journal of clinical investigation, 2015Am Soc Clin Investig
Extracellular ATP is a signal of tissue damage and induces macrophage responses that
amplify inflammation and coagulation. Here we demonstrate that ATP signaling through
macrophage P2X7 receptors uncouples the thioredoxin (TRX)/TRX reductase (TRXR)
system and activates the inflammasome through endosome-generated ROS. TRXR and
inflammasome activity promoted filopodia formation, cellular release of reduced TRX, and
generation of extracellular thiol pathway–dependent, procoagulant microparticles (MPs) …
Extracellular ATP is a signal of tissue damage and induces macrophage responses that amplify inflammation and coagulation. Here we demonstrate that ATP signaling through macrophage P2X7 receptors uncouples the thioredoxin (TRX)/TRX reductase (TRXR) system and activates the inflammasome through endosome-generated ROS. TRXR and inflammasome activity promoted filopodia formation, cellular release of reduced TRX, and generation of extracellular thiol pathway–dependent, procoagulant microparticles (MPs). Additionally, inflammasome-induced activation of an intracellular caspase-1/calpain cysteine protease cascade degraded filamin, thereby severing bonds between the cytoskeleton and tissue factor (TF), the cell surface receptor responsible for coagulation activation. This cascade enabled TF trafficking from rafts to filopodia and ultimately onto phosphatidylserine-positive, highly procoagulant MPs. Furthermore, caspase-1 specifically facilitated cell surface actin exposure, which was required for the final release of highly procoagulant MPs from filopodia. Together, the results of this study delineate a thromboinflammatory pathway and suggest that components of this pathway have potential as pharmacological targets to simultaneously attenuate inflammation and innate immune cell–induced thrombosis.
The Journal of Clinical Investigation