P2Y12 Inhibition Suppresses Proinflammatory Platelet–Monocyte Interactions

Abstract

Background Monocyte–platelet aggregates (MPAs) represent the crossroads between thrombosis and inflammation, and targeting this axis may suppress thromboinflammation. While antiplatelet therapy (APT) reduces platelet–platelet aggregation and thrombosis, its effects on MPA and platelet effector properties on monocytes are uncertain. Objectives To analyze the effect of platelets on monocyte activation and APT on MPA and platelet-induced monocyte activation. Methods Agonist-stimulated whole blood was incubated in the presence of P-selectin, PSGL1, PAR1, P2Y12, GP IIb/IIIa, and COX-1 inhibitors and assessed for platelet and monocyte activity via flow cytometry. RNA-Seq of monocytes incubated with platelets was used to identify platelet-induced monocyte transcripts and was validated by RT-qPCR in monocyte-PR co-incubation ± APT. Results Consistent with a proinflammatory platelet effector role, MPAs were increased in patients with COVID-19. RNA-Seq revealed a thromboinflammatory monocyte transcriptome upon incubation with platelets. Monocytes aggregated to platelets expressed higher CD40 and tissue factor than monocytes without platelets (p < 0.05 for each). Inhibition with P-selectin (85% reduction) and PSGL1 (87% reduction) led to a robust decrease in MPA. P2Y12 and PAR1 inhibition lowered MPA formation (30 and 21% reduction, p < 0.05, respectively) and decreased monocyte CD40 and TF expression, while GP IIb/IIIa and COX1 inhibition had no effect. Pretreatment of platelets with P2Y12 inhibitors reduced the expression of platelet-mediated monocyte transcription of proinflammatory SOCS3 and OSM. Conclusions Platelets skew monocytes toward a proinflammatory phenotype. Among traditional APTs, P2Y12 inhibition attenuates platelet-induced monocyte activation.

Effect of P2Y12 Inhibitors on Organ Support–Free Survival in Critically Ill Patients Hospitalized for COVID-19

“…We hypothesized that a focus on antagonism of the P2Y12 receptor pathway alone would be beneficial in patients with COVID-19 by modulating not only platelet aggregation and thrombosis but also platelet-mediated inflammation. 22,23 As such, the ACTIV-4a platform focused antiplatelet investigations on potent P2Y12 inhibitors and specifically ticagrelor. Contrary to our hypothesis, we found no benefit in critically ill and noncritically ill patients.…”

“…The lack of demonstrable benefit of antiplatelet therapies in patients hospitalized for COVID-19 in previous trials could be partially explained by the testing of platelet inhibitors of multiple pathways (aspirin and P2Y12 inhibitors). We hypothesized that a focus on antagonism of the P2Y12 receptor pathway alone would be beneficial in patients with COVID-19 by modulating not only platelet aggregation and thrombosis but also platelet-mediated inflammation . As such, the ACTIV-4a platform focused antiplatelet investigations on potent P2Y12 inhibitors and specifically ticagrelor.…”

microRNAs and thrombo-inflammation: relationship in sight

“…A direct link between P2Y 12 and thrombo-inflammation has recently been reported [40 ▪ ]. Rolling et al [40 ▪ ] showed that ex-vivo incubation of platelets with P2Y 12 inhibitors reduced platelet-induced monocyte recruitment toward a proinflammatory profile, changes in the transcriptome, and thus the formation of monocyte-platelet aggregates (MPAs).…”

“…A direct link between P2Y 12 and thrombo-inflammation has recently been reported [40 ▪ ]. Rolling et al [40 ▪ ] showed that ex-vivo incubation of platelets with P2Y 12 inhibitors reduced platelet-induced monocyte recruitment toward a proinflammatory profile, changes in the transcriptome, and thus the formation of monocyte-platelet aggregates (MPAs). Several studies have demonstrated the regulation of P2Y 12 by miRNAs [41,42], and the association between miR-223 and miR-126 levels and platelet function in patients with acute coronary syndrome [42].…”

“…Rolling et al [40 ▪ ] recently described higher levels of MPAs and higher expression of typical proinflammatory markers, CD11b and tissue factor (TF), in platelet-bound monocytes in patients with both COVID-19 and systemic lupus erythematosus (SLE) compared to healthy individuals. Thus, the authors proposed that TF induced by platelet-monocyte interaction is an additional way to activate coagulation in thrombo-inflammation [40 ▪ ]. The regulation of TF expression by miRNAs has been reported by several groups.…”