G-CSF treatment induces ROS in HSPCs and rescues Nrf2^−/− HSPC transplantation. (A) G-CSF treatment induces ROS in KSL cells. Nrf2^+/+ and Nrf2^−/− mice were treated with 100 μg/kg of G-CSF daily for 1 week and their BM was examined for ROS using H₂-CM-DCFDA. G-CSF induces a 3-fold increase in ROS in the KSL compartment. Data are mean values from 3 mice in each group. *P < .05. (B) G-CSF treatment rescued the hematopoietic transplantation defect in the Nrf2^−/− HSPCs. Nrf2^+/+ and Nrf2^−/− mice were treated with 100 μg/kg of G-CSF daily for 1 week. CD45.2 BM cells (250 000) from each genotype were transplanted with 250 000 CD45.1 competitor cells, and peripheral blood was examined for chimerism at the indicated time points. Peripheral blood chimerism was higher mice transplanted with Nrf2^−/− cells, but this was not statistically significant (P = .19), at 20 weeks after transplantation (n = 5 in each group). (C) G-CSF treatment does not improve in vitro myeloid colony formation of Nrf2^−/− BM. Nrf2^+/+ and Nrf2^−/− mice were treated with 100 μg/kg of G-CSF daily for 1 week, 20 000 unsorted BM cells were plated in methylcellulose medium supplemented with cytokines, and colonies were scored at 14 days. Data represent mean colony number from 3 separate mice each plated in duplicate (normalized to untreated wild-type). *P < .03.