Fig 1: P2Y12 inhibition reduces platelet S100A8 and S100A9 expression and platelet-mediated EC activation.A cohort of patients received (A) aspirin daily (n = 63) or (B) ticagrelor (90 mg) twice daily for 4 weeks (n = 49). Blood was collected and platelet RNA was extracted before the commencement of the study and following 4 weeks of antiplatelet therapy. Plots depict normalized expression counts of S100A8 and S100A9 at baseline and following 4 weeks of antiplatelet therapy. ****P < 0.0001 as determined by paired t test. (C) Forest plot of log fold change (LogFC) between baseline and follow-up platelet S100A8 and S100A9 expression. Data are means and 95% CI. (D) Expression of IL6, IL8, and CCL20 following exposure of ECs to platelet releasate generated in the presence of aspirin (1 mM), AZD1283 (1 μM, P2Y12 inhibitor), or eptifibatide (18 μM, glycoprotein IIb/IIIa inhibitor) for 6 hours. Data expressed relative to platelet releasate–treated cells in the absence of platelet inhibitors. n = 6 unique releasate donors. Data are means ± SEM, expressed relative to the platelet releasate–treated ECs; *P < 0.05, **P < 0.01, ****P < 0.0001 by paired t test.
Fig 2: Platelet-released MRP8/14 induce EC activation.(A) Correlation of platelet S100A8/9 mRNA expression and the expression of identified EC pathways enriched following exposure to COVID-19–derived platelet releasate. (B) Boxplots of platelet MRP8/14 releasate in COVID-19 and control samples (y axis) and boxplots of the relative eigengene values for the apical junction, coagulation, and TNFα signaling pathways (x axis). Correlation of the respective values shown in scatterplots. (C) Dotplot depicting the correlation value of the relative eigengene expression of each pathway to its respective metadata metric. Pathways dysregulated in ECs are shown on the y axis, and various metadata are shown on the x axis. The top annotation shows the Wilcoxon P value for the population difference of the respective metadata metric between COVID-19 samples and controls. Platelet heteroaggregates: MPA, leukocyte platelet aggregates (LPA), NPA, lymphocyte platelet aggregates (LYPA). Platelet aggregation: Spontaneous (PBS), submaximal ADP (0.1 μM), epinephrine (0.1 μM), collagen (0.2 μM). Mean platelet volume (MPV). (D) Quantification of IL8 and IL6 release from microvascular ECs in response to treatment with platelet releasate isolated from COVID-19 patients or controls. Data are means ± SEM; *P < 0.05, as determined by t test. (E) Correlation between released IL6 and IL8 by microvascular ECs and MRP8/14 concentration in platelet releasate. (F) Quantification of IL8 and IL6 release from microvascular ECs in response to treatment with platelet releasate isolated from COVID-19 patients or controls. CD36 silencing and EC transfection with CD36 small interfering RNA (siRNA) (or ctrl siRNA) for 72 hours before addition of platelet releasate. Data are expressed relative to each corresponding vehicle control + platelet releasate and are means ± SEM; *P < 0.05, as determined by t test; n = 6 to 7 subjects per group.
Supplier Page from BioLegend for LEGENDplex™ Human Thrombosis Panel (3-plex) w/FP