Platelet-derived extracellular vesicles alter hematopoiesis in vitro. (A) BM from cMpl^−/− mice was flushed and cultured in the presence or absence of wild-type (MPL⁺), CMPTX-labeled PEVs (PEVs from 2 donors: 1 recipient; 12 × 10⁷ particles: 9 × 10⁶ BM cells) for 72 hours. Indicated cultures were also supplemented with TPO (70 ng/mL). (B) Cultures were monitored by live-cell microscopy that revealed an increase in large MKs in the cultures treated with PEVs, which were also fluorescent. After 72 hours in culture, the percentage of CD41⁺ cells was quantified by flow cytometry. (C) Cultures treated with PEVs had significantly increased numbers of CD41⁺ cells. (D) Representative forward and side scatter plot showing that CD41⁺/ CMPTX (PEV)⁺ events (blue) are the largest in the sample. (E) Percentage of CD41⁺ cells that are also positive for CMPTX (PEV-derived) fluorescence. Data are mean ± SEM of 3 independent experiments; scale bars, 50 µm, *P < .05 **P < .01 (1-way analysis of variance with multiple comparison post hoc test).