Platelet secretion in inflammatory and infectious diseases

Abstract

Platelets are small, anucleate circulating cells that possess a dynamic repertoire of functions spanning the hemostatic, inflammatory, and immune continuum. Once thought to be merely cell fragments with responses limited primarily to acute hemostasis and vascular wall repair, platelets are now increasingly recognized as key sentinels and effector cells regulating host responses to many inflammatory and infectious cues. Platelet granules, including α-granules and dense-granules, store hundreds of factors and secrete these mediators in response to activating signals. The cargo packaged and stored within platelet granules orchestrates communication between platelets and other circulating cells, augments host defense mechanisms to invading pathogens and tumor cells, and – in some settings - drives dysregulated and injurious responses. This focused review will highlight several of the established and emerging mechanisms and roles of platelet secretion in inflammatory and infectious diseases.

Platelet depletion limits the severity but does not prevent the occurrence of experimental transfusion‐related acute lung injury

“…Platelets possess significant proinflammatory secretory capacity, particularly through the exocytosis of different granules. [18][19][20][21] They express a multitude of receptors that are sensitive to inflammatory danger signals, such as toll-like receptors (TLRs). 22,23 Finally, platelets play an active role in the induction, maintenance, amplification, [24][25][26] and regulation [27][28][29][30] of the inflammatory process by interacting directly with other cells, including neutrophils.…”

“…Platelets possess significant proinflammatory secretory capacity, particularly through the exocytosis of different granules . They express a multitude of receptors that are sensitive to inflammatory danger signals, such as toll‐like receptors (TLRs) .…”

Reproductive Behaviour, Hematological Profile and Monogenean Microfauna of the Nest-Breeding, Nile Green Tilapia (Tilapia zilli) Gervais, 1848

“…According to [39,40,41] the blood platelets (thrombocytes) attain the ability to phagocytose pathogens and play a role in the defense mechanisms. [42] suggested that the thrombocytes act as a link between the innate and adaptive immune systems of the fish.…”

Glycoprotein VI in securing vascular integrity in inflamed vessels

“…Platelets have long been considered primarily through the lens of hemostatic platelet plug formation and thrombosis, who both rely on integrin‐mediated platelet aggregation. They are, however, increasingly recognized as major actors of inflammatory reactions and immune responses . Platelets intervene at various stages of inflammatory reactions.…”

“…They are, however, increasingly recognized as major actors of inflammatory reactions and immune responses. [71][72][73][74][75][76][77] Platelets intervene at various stages of inflammatory reactions. Whereas platelets enhance the barrier function of the quiescent endothelium and stop bleeding in case of vessel injury, 68 in the context of inflammation, they contribute to opening of endothelial junctions and thereby to edema formation.…”