All samples were analyzed by flow cytometry using a FACSAriaTM III (BD biosciences, San Jose, CA, USA). CD45 (Clone 104) (Biolegend, San Diego, CA, USA), CD45.1 (Clone A20) (BD Biosciences), CD45.2 (Clone 104) (Biolegend), EPCR (CD201) (Clone eBio1560, eBioscience, San Diego, CA, USA), CD150 (Clone mShad150, eBioscience), and CD48 (Clone HM48–1, Biolegend) antibodies were used to enumerate CD45+EPCR(CD201)+CD48CD150+ (E-SLAM) cells.[22 (link),23 (link)] MKs were sorted on the basis of CD41 expression (Clone MWReg30, Biolegend) and cell size.[15 (link)] CD45 (Clone 104) (Biolegend) and CD31 (Clone 390, BD biosciences) antibodies were used to isolate CD45CD31+ marrow ECs.[24 (link)]