Ex vivo expansion of human hematopoietic stem cells by direct delivery of the HOXB4 homeoprotein.
Expansion of human hematopoietic stem cells (HSCs) is a major challenge in cellular therapy, and currently relies on the use of recombinant cytokines or on gene transfer of transcription factors. Of these, the HOXB4 homeoprotein protein is of particular interests as it promotes the expansion of mouse HSCs without inducing the development of leukemia. To eliminate any deleterious effects that might be associated with stable HOXB4 gene transfer into human cells, we took advantage of the ability of HOX proteins to passively translocate through cell membranes. Here we show that when cultured on stromal cells genetically engineered to secrete HOXB4, human long-term culture-initiating cells (LTC-ICs) and nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mouse repopulating cells (SRCs) were expanded by more than 20- and 2.5-fold, respectively, over their input numbers. This expansion was associated with enhanced stem cell repopulating capacity in vivo and maintenance of pluripotentiality. This method provides a basis for developing cell therapy strategies using expanded HSCs that are not genetically modified.
Institut Cochin, Département d'Hématologie, INSERM U567, CNRS UMR 8104, Université Paris 5, Maternité Port-Royal, 123, Bd de Port-Royal, 75014 Paris, France.
Sophie
S
Amsellem
Françoise
F
Pflumio
Dominique
D
Bardinet
Brigitte
B
Izac
Pierre
P
Charneau
Paul-Henri
PH
Romeo
Anne
A
Dubart-Kupperschmitt
Serge
S
Fichelson
D000818:Animals; D002455:Cell Division / Q000502:physiology*; D018920:Coculture Techniques; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D013234:Stem Cells / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
C090460:HOXB4 protein, human; D018398:Homeodomain Proteins; C513262:Hoxb4 protein, mouse; D014157:Transcription Factors