Transcriptome analysis of LT-HSC isolated from WT and CD169DTR/+ mice 5 days after a 2 Gy-Total Body Irradiation

A 2 Gy-total body irradiation (TBI) of WT mice induces a second wave of ROS and a second wave of apoptosis in hematopoietic stem cells starting from 6 days after irradiation. In CD169DTR/+ mice, which are depleted in CD169+ resident macrophages after a diphtheria toxin injection, these two waves do not occur and a total recovery of the LT-HSC pool is observed, contrarily to the LT-HSC pool from WT mice, which is decreased. Our goal is to understand why these secondary waves of apoptosis and ROS occur in LT-HSC from irradiated WT mice and not in LT-HSC from irradiated mice depleted in resident macrophages, allowing a recovery of the LT-HSC pool. We used microarrays to compare the global gene expression in LT-HSC isolated from WT and CD169DTR/+ mice 5 days after irradiation, i.e. just before both secondary waves of ROS and apoptosis occurred in WT mice. Two distinct experiments have been performed to obtain two replicates for each condition (i.e. for both mouse strains, irradiated or not).