LSD1 inhibition and UM171 trigger similar molecular responses. GSEA plots showing HSC gene signature (A) and UM171-induced gene signature (B) in UCB HSC fraction treated with 2-PCPA for 24 hours. (C) LSD1-knockout (KO) gene signature in UCB HSC fraction treated with UM171 for 6 days. Microarray was performed in triplicates, and normalized enrichment score (NES) and q value were calculated with GSEA using reference gene sets from the indicated publications.^8,12,24  FACS plots showing the frequency (D) and graphs showing the total numbers (E) of mast cell progenitors in cultures treated with 2-PCPA or UM171. Data from 4 replicates from 1 of 2 independent experiments with similar results. (F) Western blot showing H3K4me2 and H3K9me2 marks after 2-PCPA or UM171 treatment. (G) Relative increase in H3K4me2 compared with H3. ****P ≤ .0001.