Figure 4. Lung-resident Mks respond to acute thrombocytopenia.

(A) Mice were given CFSE o.p. and LPS or PBS i.p. LPS reduced platelet, but not Mk, counts and increased lung-derived platelets (n = 3–5 per group; results are representative of 2 independent experiments). (B) IFN-γ had no effect on platelet counts or CFSE⁺ platelets (n = 5 per group, representative shown from 2 independent experiments). (C) PF4^Cre-iDTR mice treated with DT had reduced platelet counts (n = 5–9 per group from 2 independent experiments) and increased CFSE⁺ lung-derived platelets (n = 5 per group; results are representative of 2 independent experiments). DT treatment reduced BM and lung total Mks as well as CFSE⁺ Mks on day 2 after DT administration (n = 5 per group; results are representative of 2 independent experiments). (D) CFSE⁺ Mks relative to total Mks in control mice increased on day 7 after DT when Mk and platelet counts were recovered (n = 5 per group; results are representative of 2 independent experiments). Data indicate the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001; (A and C) platelet count: multiple t tests with Holm-Šidák multiple-comparison correction; CFSE percentage and CFSE normalized: unpaired, 2-tailed t test; Mks: 2-way ANOVA with Tukey’s multiple-comparison correction; CFSE⁺ Mks: unpaired, 2-tailed t test; (B) unpaired, 2-tailed t tests; (D) Mks: 2-way ANOVA CFSE⁺ Mks: unpaired, 2-tailed t test.