Platelets possess a range of receptors, which are either exclusively used for pathogen interaction, i.e., TLR4 and NOD2, or are primarily important in hemostasis function but can directly or indirectly bind pathogens, like Gp1b or GPIIbIIIa. Downstream of these receptors, platelets also contain the required innate immune signaling machinery, i.e., NLRP3 inflammasomes, and components of cGAS-STING. Upon engagement, platelets can activate multiple effector functions, including migration, collection, and bundling of bacteria; procoagulant transformation; mtDNA release and granule as well as microparticle release. All these functions can contribute to host defense, but also mediate tissue damage in hyperinflammation. Figure created using BioRender.
