Comparison of the effects of AZA or TSA treatment on HSC self-renewal in distinct bone marrow conditions. (A) Schematic illustration of the experimental design comparing the effects of AZA and TSA treatment on HSCs during the regenerative or stationary phase in bone marrow. (Top panel) Epigenetic treatment on HSCs during the regenerative phase of bone marrow. Donor bone marrow cells (105/mouse; Pep 3b, Ly5.1) were transplanted into lethally irradiated recipient mice (BL6, Ly5.2; n = 3). Recipient mice were then injected daily with AZA or TSA for 2 weeks starting 3 days after transplantation, the time period when transplanted HSCs undergo active self-renewal.27 After 16 weeks, the total number of donor-derived CRU regenerated in the primary recipients was determined by a limiting dilution analysis into secondary recipient mice. (Bottom panel) Epigenetic treatment on HSCs during the stationary phase of bone marrow. Mice (Pep3b, Ly5.1) in the homeostatic phase were injected daily with TSA or AZA for 2 weeks, and CRU frequencies and total CRU numbers in the bone marrows of treated mice were determined by a limiting dilution analysis. (B) Effects of epigenetic treatment on HSC self-renewal during the regenerative (i) and stationary (ii) phases of bone marrow. Shown are the CRU frequencies of donor-derived cells determined by Poisson statistics. CRU frequencies and 95% CIs were calculated by applying Poisson statistics. Total number of CRU in the mice was calculated assuming that 2 femurs and tibias represent 25% of the total marrow.
