Abstract
Foxm1 is known as a typical proliferation-associated transcription factor. Here we found that Foxm1 was essential for maintenance of the quiescence and self-renewal capacity of hematopoietic stem cells (HSCs) in vivo in mice. Reducing expression of FOXM1 also decreased the quiescence of human CD34(+) HSCs and progenitor cells, and its downregulation was associated with a subset of myelodysplastic syndrome (MDS). Mechanistically, Foxm1 directly bound to the promoter region of the gene encoding the receptor Nurr1 (Nr4a2; called 'Nurr1' here), inducing transcription, while forced expression of Nurr1 reversed the loss of quiescence observed in Foxm1-deficient cells in vivo. Thus, our studies reveal a previously unrecognized role for Foxm1 as a critical regulator of the quiescence and self-renewal of HSCs mediated at least in part by control of Nurr1 expression.