Beyond Hemostasis: Platelet Innate Immune Interactions and Thromboinflammation

There is accumulating evidence that platelets play roles beyond their traditional functions in thrombosis and hemostasis, e.g., in inflammatory processes, infection and cancer, and that they interact, stimulate and regulate cells of the innate immune system such as neutrophils, monocytes and macrophages. In this review, we will focus on platelet activation in hemostatic and inflammatory processes, as well as platelet interactions with neutrophils and monocytes/macrophages. We take a closer look at the contributions of major platelet receptors GPIb, alpha(IIb)beta(3), TLT-1, CLEC-2 and Toll-like receptors (TLRs) as well as secretions from platelet granules on platelet-neutrophil aggregate and neutrophil extracellular trap (NET) formation in atherosclerosis, transfusion-related acute lung injury (TRALI) and COVID-19. Further, we will address platelet-monocyte and macrophage interactions during cancer metastasis, infection, sepsis and platelet clearance.

Automated summary

There is growing evidence that platelets have functions beyond their traditional roles in thrombosis and hemostasis. They interact and regulate cells of the innate immune system, such as neutrophils, monocytes, and macrophages, and play roles in inflammatory processes, infection, and cancer. This review focuses on platelet activation in hemostatic and inflammatory processes, as well as platelet interactions with neutrophils and monocytes/macrophages. The contributions of major platelet receptors and secretions from platelet granules on platelet-neutrophil aggregate and neutrophil extracellular trap (NET) formation in various diseases are examined.