OBJECTIVE: Synergy between @entity24817 and @entity24778 produces a marked expansion of hematopoietic progenitor cells and mobilizes large numbers of stem cells into the peripheral blood. To determine if the activation of the @entity33868 and @entity24778 receptors enhances the regenerative capacity of the hematopoietic compartment, we evaluated whether activation of these receptors augments stem cell recovery following lethal doses of radiation. METHODS: C57BL/6 @entity19 received a single injection of the bi-functional @entity33868 and G-GSF agonist progenipoietin-1, 24 hours prior to exposure to 1100 cGy of gamma radiation. Survival, hematopoietic reconstitution, and competitive repopulation potential were evaluated. RESULTS: All cytokine-treated @entity19 survived for up to 9 months. Radioprotected recipients exhibited stable multilineage @entity1210 and recovered normal numbers of T cells, B cells, and myelomonocytic cells in the blood, bone marrow, and thymus. Between 2 and 3 weeks following radiation, cytokine-treated @entity19 demonstrated threefold higher serum hemoglobin levels, 10-fold higher nucleated blood cell counts, and 20-fold higher platelet counts compared to controls. Radioprotection of self-renewing hematopoietic stem cells was revealed by multilineage hematopoietic reconstitution following transplantation in a competitive repopulation assay. To further evaluate the extent of cytokine-induced radioprotective activity, a cohort of @entity19 received a second cycle of cytokine treatment and a second exposure to radiation (1100 cGy). Survival of this serially irradiated group was 70% and analysis of the peripheral blood revealed sustained multilineage @entity1210 . CONCLUSION: These results demonstrate that activation of both the @entity33868 and @entity24778 receptors provides a high degree of radioprotection to the hematopoietic progenitor cell and stem cell compartment.

Activation of the XXXX and @entity33868 receptors protects hematopoietic stem cells from lethal irradiation.

@entity33868 :: ('14255(Tax:10090)', 'Gene') :: ['Flt-3'] @entity19 :: ('10090', 'Species') :: ['mice'] @entity24778 :: ('12985(Tax:10090)', 'Gene') :: ['G-CSF'] @entity24817 :: ('14256(Tax:10090)', 'Gene') :: ['Flt-3 ligand'] @entity1210 :: ('MESH:C536227', 'Disease') :: ['hematopoiesis']
@entity24778 :: (12985(Tax:10090),Gene) :: ['G-CSF']
