Figure 2. JAK2^V617F vascular niche contributes to the growth advantage of JAK2^V617F HSPC over JAK2^WT HSPC.

JAK2^WT (from control mice) and JAK2^V617F (from Tie2/FF1 mice) Lin−cKit+ HSPCs were cultured on a feeder layer of JAK2^WT or JAK2^V617F ECs under serum-free conditions. (A) There was no significant difference between JAK2^WT and JAK2^V617F HSPC proliferation in vitro in SFEM. (B) There was no significant difference between JAK2^WT and JAK2^V617F HSPC proliferation when co-cultured with JAK2^WT EC. (C) JAK2^V617F HSPC displayed a relative growth advantage over the JAK2^WT HSPC when co-cultured with JAK2^V617F EC. Cell proliferation was shown as fold of expansion which is the ratio of the final cell count to starting cell count. The results were expressed as mean ±s.e.m. (n=3) Data are from one of two independent experiments (with triplicates in each experiment) performed by two investigators (C.L. and H.Z.) that gave similar results. * p < 0.05