Colony formation and migration of human and murine hematopoietic stem and progenitor cells on cannabinoid ligand stimulation. (A) Effects of cannabinoid ligands on the in vitro colony formation by human hematopoietic progenitor cells. A total of 1 × 104 of human MNCs were seeded onto Petri dishes with or without the addition of cannabinoid ligands, as indicated. On day 10, colonies were counted under a light microscope. *P < .05. Data are mean ± SD (n = 3). (B) Effects of cannabinoid ligands on the in vitro colony formation by mouse hematopoietic progenitor cells. A total of 1 × 104 WT or Cnr2−/− BM cells were seeded onto Petri dishes suspended in colony formation-supporting medium with or without the addition of cannabinoid ligands, as indicated. On day 10, colonies were counted under a light microscope. *P < .01. Data are mean ± SD (n = 6). (C) Human BM CD34+ cells were exposed to CP55940 or JWH133 in a transwell assay. The y-axis shows percentage of migration from an input of 1 × 104 human CD34+ cells. Data are mean ± SD (n = 6). *P < .01. (D) Induction of chemotaxis of murine LSK cells by CP55940. Transwell inserts were used to evaluate the migration of LSK cells in distinct CP55940 concentrations. Cells were allowed to migrate for 4 hours, and cells in the bottom chambers were then counted under a light microscope. Data are mean ± SD (n = 9). *P < .001. (E) Murine wt or Cnr2−/− BM cells were added to the upper chamber in a migration assay. Cells were exposed to CP55940 and AM1241, present in the lower well, and migrated cells were counted. The y-axis represents percentage of migration from an input of 1 × 105 total murine BM cells. Data are mean ± SD (n = 6). *P < .01 compared with control untreated mice. **P < .01 compared with WT treated with the cannabinoid agonist, as indicated.
