Improvement of multilineage hematopoiesis in hematopoietic stem cell-transferred c-kit mutant NOG-EXL humanized mice

Abstract

Human hematopoietic stem cell (HSC)-transferred humanized mice are valuable for exploring human hematology and immunology. However, sufficient recapitulation of human hematopoiesis in mice requires large quantities of enriched human CD34+ HSCs and total body irradiation for adequate engraftment. Recently, we generated a NOG mouse strain with a point mutation in the c-kit tyrosine kinase domain (W41 mutant; NOGW mice). Herein, we first examined the potential of NOGW mice for reconstituting human hematopoietic cells. Irradiated NOGW mice exhibited a high engraftment level of human CD45+ cells in peripheral blood, even on transferring 5,000–10,000 CD34+ HSCs. The efficient engraftment of human CD45+ cells was also observed in non-irradiated NOGW mice transferred with 20,000–40,000 HSCs. The bone marrow (BM) of NOGW mice exhibited significantly more engrafted human HSCs or progenitor cells (CD34+CD38− or CD34+CD38+ cells) than the BM of NOG mice. Furthermore, we generated a human cytokine (interleukin-3 and granulocyte-macrophage colony-stimulating factor) transgenic NOG-W41 (NOGW-EXL) mouse to achieve multilineage reconstitution with sufficient engraftment of human hematopoietic cells. Non-irradiated NOGW-EXL mice showed significantly higher engraftment levels of human CD45+ and myeloid lineage cells, particularly granulocytes and platelets/megakaryocytes, than non-irradiated NOGW or irradiated NOG-EXL mice after human CD34+ cell transplantation. Serial BM transplantation experiments revealed that NOGW mice exhibited the highest potential for long-term HSC compared with other strains. Consequently, c-kit mutant NOGW-EXL humanized mice represent an advanced model for HSC-transferred humanized mice and hold promise for widespread application owing to their high versatility.