Purinergic signaling in BM-derived HPSCs, leukemic cells, and BM-derived MSCs. Recent findings suggest that purinergic signaling may affect HSCs at 2 different levels: by directly binding P2Rs on HPSCs or by targeting cells that are part of the HSC niche (such as MSCs). This figure summarizes how eNTPs directly modulate proliferation, migration, and engraftment in HPSCs and leukemic stem cells. BM-derived MSCs are also a target for eNTPs: activation of purinergic signaling in these cells has been shown to enhance their adipogenic/osteogenic differentiation, as well as the release of proinflammatory cytokines.