Lowering of the ER stress response supports faster recovery after chemotherapy. (A) The experimental setup of 5-FU and SB injection into mice. (B-D) Cellularity in BM and PB of the SB-treated mice on day 8. Total BM cells (B), BM lineage⁻ cells (C), BM B cells (D), and PB B cells (E) in femur and tibia are shown. (F) The experimental setup of 5-FU treatment of Ddit3 KO mice (n = 13). (G-K) Cellularity in BM and PB of treated Ddit3 KO mice on day 8. Total BM (G), lineage⁻ cells (H), c-kit⁺ cells (I), KSL cells (J), and HSCs (defined as CD150⁺CD48⁻ KSL) (K) in BM of the treated Ddit3 KO mice are shown (n = 11). (L) Lineage⁻ BM cells of WT or Ddit3 KO mice on day 8 after 5-FU treatment, with or without supplementation of TUDCA. Mice were compared with KO mice that were treated with PBS (n = 5-15). Results are presented as means ± SEM. *P < .05; **P < .01; ***P < .001.