Analysis of hematopoiesis in the EP4 KO mouse. (A) PB analysis of B (B220), T (CD4/CD8), and myeloid (Mac-1/Gr-1) cells in 8-week-old WT (n = 13) and EP4 KO (n = 11) mice. Data represent means ± SD (*P < .01; **P < .05). (B) The number of CFU-Cs and HPP-CFCs. Fifty LSK cells were cultured per dish. Data represent means ± SD (n = 3). (C) Representative FACS profiles of LSKCD34^–Flt3^– cells (left panels) and LSKCD41^–CD48^–CD150⁺ cells (right panels) in WT (upper panels) and EP4 KO mice (lower panels). (D) Percentage of LSK cells, LSKCD34^–Flt3^– cells, and LSKCD41^–CD48^–CD150⁺ cells among the total BM MNCs. Data represent means ± SD (n = 7/group). (E) Efficiency of EP4 KD by shEP4-1 and shEP4-2 in LSK cells. Two days after transduction of shEP4-1, shEP4-2, or scrambled shRNA into LSK cells, GFP⁺LSK cells were sorted and cultured for 1 week. GFP⁺LSK cells were then resorted, and EP4 expression was analyzed by qPCR. Data represent means ± SD (*P < .01, n = 4). (F) Effects of EP4 shRNA on the LTR capacity of LSK cells. Percentages of GFP⁺ donor-derived (Ly5.1⁺) cells in recipient mice 3 months after BMT are shown. Data represent means ± SD (*P < .01, n = 5/group). Data are representative of 2 independent experiments.