Pluripotin facilitates the expansion of hematopoietic stem cells, but restricts the growth of fibroblasts and the proliferation of mesenchymal stem cells from the bone marrow

Abstract

Hematopoietic stem/progenitor cell (HSPC) quiescence modulators play a key role in the modulation of HSPC numbers. Targeting HSPC modulators with small molecules could contribute to the cell cycle entry and expansion of HSPC. To this end, we have investigated the effect of two small molecules Pluripotin and CHIR-99021 on HSPC expansion. Both Pluripotin and CHIR-99021 have been shown to result in a 3-fold rise in the murine pool of HSPC in a dose-dependent compartment after 7 days of treatments. In addition, we investigated the influence of Pluripotin treatment on the ex vivo expansion of human umbilical cord blood and bone marrow mononuclear cells. In specific, Pluripotin treatment increased human CD34 + and ALDHbr HSPC content up to 3-fold compared to control. In addition, human CD133 + HSPC cell content was increased to 5-fold following treatment with Pluripotin. Intriguingly, we find that Pluripotin treatment inversely changes bone marrow-derived mesenchymal stem cell (MSC) proliferation and lowers fibroblast growth although there is no effect on adipose-derived MSCs. CHIR-99021 treatment did not have any effect in proliferation of MSCs or fibroblasts. In conclusion, Pluripotin-induced stem cell expansion is unique to HSPCs that can be used to expand HSPCs and reduce unwanted fibroblast or MSC growth in the primary ex vivo cultures.