LSD1 inhibitors increase HbF in primary human erythroid progenitor CD34⁺cells and in sickle iPSC-derived erythroblasts (SS24 cells). (A) Representative flow cytometry plots of HbF-stained cultured CD34⁺ cells treated with LSD1 inhibitors. After 7 days of expansion and 3 days in differentiation phase, cells were treated with 0.05 and 0.1 μM OG-L002 or 0.02 and 0.1 μM GSK-LSD1 along with controls (50 μM HU, 2 and 4 μM TC, 0.05 and 0.1 μM RN-1, PBS, or DMSO) for a further 5 days in differentiation culture. (B) CD34⁺ cells flow cytometry data shown as bar graphs. Representative histograms showed the fluorescence (C), and mean fluorescence intensity (D), of the treated CD34⁺ cells compared with controls. (E) SS24 cells were recovered in expansion media for 3 days and then treated with 0.1 and 0.5 μM OG-L002 or 0.1 and 0.5 μM GSK-LSD1 along with controls (50 μM HU, 4 and 8 μM TC, 0.1 and 0.5 μM RN-1, PBS, or DMSO) for 3 additional days in expansion media. Flow cytometry data of HbF-stained cultured cells treated with drugs or controls shown as bar graphs. (All data represent the average of 3 independent biological replicates. All statistical analyses were calculated using an unpaired 2-tailed Student t test. *P < .005 and **P < .0005.)