Gene expression signatures of megakaryocytes post-IR

Platelets are anucleated blood cells that are produced by their progenitor cell, the megakaryocyte (MK). Platelets are centrally positioned in hemostasis and thrombosis and, according to the recent findings, play key roles in innate immunity, inflammation, atherogenesis, and cancer metastasis. The quantitative and qualitative properties of platelets are crucial determinants of their hemostatic function. While the regulatory mechanisms of platelet number and size have been studied separately, critical questions remain regarding the interplay of platelet number and size in hemostasis. In this study, using a mouse model of irradiation (IR)-induced thrombocytopenia, we show that mature MKs (mMKs) are resistant to IR and maintain the nadir platelet levels post IR. To identify the phenotype switching and function variation in BM MKs post IR, we performed microarray expression profiling of MKs from the bone marrow of mice at 1- or 3-days post IR and control mice (Ctrl). Radiation induced gene expression in MK was measured at 1 and 3 days after exposure to doses of 5 Gy g-rays. Three independent experiments were performed at each time using different donors for each experiment.