Fig. 6

IFN-inducible GTPase GBP2 mediates production of large and hyperreactive platelets post IR. a Relative IFN-β mRNA expression in BM mMKs of mice at indicated dpi (n = 3). b IFN-β level in BM extracellular fluid of mice at indicated dpi was assessed by ELISA (n = 5). c Western blotting analysis and quantification of IFN-β and p-STAT1 expression in BM mMKs of mice at 1 dpi (n = 3). d IFN-β and p-STAT1 expression in BM mMKs of mice at 1 dpi were assessed by immunofluorescence staining. Scale bar = 20 μm. e Flow cytometric analysis and quantification of IFN-β and p-STAT1 expression in BM mMKs of mice at 1 dpi (n = 5). f Flow cytometric analysis and quantification of IFN-β and p-STAT1 expression in BM mMKs of Sting^fl and Sting^cko mice at 1 dpi (n = 5). g MPV in peripheral blood of Ifnar1^fl and Ifnar1^cko mice at indicated dpi (n = 5). h CD62P expression in response to thrombin on washed platelets from Ifnar1^fl and Ifnar1^cko mice at indicated dpi (n = 4–5). i Basic and relative mRNA expression of IFN-inducible GTPases as assessed by microarray in BM mMKs of mice at indicated dpi (n = 3). j Flow cytometric analysis and quantification of GBP2 expression in BM mMKs of mice at 3 dpi (n = 5). k Western blotting analysis and quantification of GBP2 expression in BM mMKs of mice at 3 dpi (n = 3). l FSC-area and CD62P expression in response to thrombin of PLPs from Meg-01 cultures with or without siGBP2 treatment at 3 dpi (n = 5). Data represent mean ± standard deviation. ^*P < 0.05, ^**P < 0.01, compared to Ctrl, IR/Sting^fl, IR/Ifnar1^fl or siCtrl as indicated. Two-tailed unpaired student’s t-test. IFN interferon, GBP2 guanylate-binding protein 2, mMK mature megakaryocyte, Ctrl control, IR ionizing radiation, BM bone marrow, dpi day post IR, BMECF BM extracellular fluid, ELISA enzyme-linked immunosorbent assay, STAT1 signal transducer and activator of transcription 1, STING stimulator of interferon genes, IFNAR1 IFN‐α/β receptor 1, MPV mean platelet volume, FSC forward scatter, PLP platelet-like particle, siGBP2 siRNA of GBP2, DAPI 4′,6-diamidino-2-phenylindole, GAPDH glyceraldehyde-3-phosphate dehydrogenase