RBC-derived MPs and monocyte crosstalk. (A) Transmission electron microscopy images of P2 (10 000g), P3 (37 000g), and P4 (200 000g) MPs. Scale bar = 200 nm. (B) Internalization or CFSE-labeled P3 MPs by PMA-treated THP-1s. Scale bar = 10 μm. (C) Ceramide (Cer) and SM quantification with HPLC-MS. (D) Sphingosine and S1P quantification in RBCs and MPs. (E) Fold change over vehicle in cytokine production, and (F) secretion of PMA-treated THP-1s after non-SCD microparticle (AAMP) and SCD microparticle (SSMP) incubation relative to untreated cells (dotted line). (G) Fold change over vehicle in cytokine production, and (H) secretion of primary AA monocytes after SSMP incubation relative to untreated cells. *P < .05 measured in ANOVA relative to vehicle or AA.