FoxO1 regulates human haematopoietic stem cells self-renewal and engraftment

Hematopoietic stem cell transplantation (HSCT) is one of the most effective ways to treat hematological malignant diseases, but the traditional culture of hematopoietic stem cells (HSCs) in vitro will soon lose their ability to self-renewal or differentiate into multilineage blood cells.

To determine whether Forkhead boxO1 (FoxO1) is implicated in the development of HSCs, lentiviral vectors expressing knockdown (KD) or overexpression (OE) of FoxO1 were utilized in fetal liver-derived hematopoietic stem and progenitor cells (FL-HSPCs). The impacts on the proliferation and hematopoietic differentiation of FL-HSPCs were subsequently evaluated via flow cytometry (FCM). Furthermore, the effect of FoxO1-OE on the self-renewal of cord blood-derived hematopoietic stem and progenitor cells (CB-HSPCs) was investigated. Additionally, the transplantation ability of hematopoietic stem cells derived from these CB-HSPCs in mice after secondary transplantation was also assessed by FCM.

After knocking down FoxO1 in FL-HSPCs, the apoptosis rate was significantly increased, and the expression of hCD45 was significantly decreased. Conversely, overexpression of FoxO1 reversed this phenomenon, effectively promoting the expansion and differentiation of FL-HSPCs in vitro. Similarly, it was found that FoxO1-OE could effectively enhance the expansion of CB-HSPCs. Furthermore, upon transplantation of CB-HSPCs overexpressing FoxO1 into NSG mice, multilineage human hematopoietic reconstruction was promoted. Notably, the results of secondary transplantation revealed that only the FoxO1-OE group exhibited multilineage reconstitution.

In conclusion, our study confirmed that FoxO1-OE could enhance the self-renewal and engraftment of CB-HSPCs.