Fig. 4: Inhaled particles activate MKs to release platelets into blood circulation. | Nature Communications

Fig. 4: Inhaled particles activate MKs to release platelets into blood circulation.

From: Lung megakaryocytes engulf inhaled airborne particles to promote intrapulmonary inflammation and extrapulmonary distribution

Fig. 4

a Fluorescent images of lung sections from PF4-mTmG mice treated with 2 mg/kg body weight Cy5-PSs for 24 h and untreated control. White arrow pointing to MKs with engulfed particles releasing platelets (white arrowhead). b Fluorescent image of lung MK releasing a nascent platelet (green arrow) into a Alexa Fluor 647-dextran dye -stained blood capillary (red arrow). c Number of resting and activated platelets in peripheral blood of CB particle-treated mice (n = 8). d Flow cytometer analysis plots of activated platelets (488SSC-405SSC+/lowCD41+CD62P+) in peripheral blood of control and CB particle-treated animals from c. e Scanning electron microscope images of resting and activated platelet from CB-treated animals. f Peripheral blood of mice (n = 8) treated with CB for 24 h clotted faster than untreated control. g Bright-field images and counts per field show more platelets (blue arrowheads) from platelet-rich plasma (PRP) of CB particle-treated mice attached on the collagen matrix than untreated control (n = 10 randomly captured images). h KEGG pathway enrichment analysis of upregulated genes associated with MK development and platelet production, one-side Fisher’s exact test. MKs were isolated from mice treated with CB particles for 24 h. i Ex vivo maturation assay involves culturing isolated CD41+ MKs in TPO/SCF/IL-6 medium. Fluorescent images of membrane-stained matured MKs and nascent platelets after 2 days. j Live-cell imaging of isolated MKs with engulfed Cy5-PSs using LSFM features an extended cytoplasm and membrane shedding nascent platelet clusters (white dotted lines). k, l Flow cytometer analysis of the number of total platelets (CD41+Hoechst-, k) and activated platelets (CD41+CD62p+Hoechst-, l) in culture medium. MKs were pretreated with 200 ng/mL Cy5-PSs and cultured for 2 days (n = 10 biological replicates). m Schematic showing that particle inhalation induces greater activated platelets in circulation than physiological conditions. Box and whisker plots indicate median, interquartile range and 10th to 90th percentiles of the distribution (f, g). Data are presented as the mean values of 3 independent experiments ± SEM (c, f, g, k and l), two-side student’s t-test (c, f, g, k and l). Figure 4i and m, created with BioRender.com, released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license.

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