HOXB4 overexpression increases cord blood CD34+ hematopoietic stem cells population during ex vivo expansion

Nowadays، cord blood hematopoietic stem cells (HSCs) are well known as a very valuable source of cells for cell therapy purposes. But unfortunately، the insufficient number of them is a limiting factor for their employment in adult bone marrow transplantation. Cord blood HSCs expansion is an approach for alleviating this problem. It has been shown by several studies during in vivo investigations in mouse models that HOXB4 is one of the most effective tools for inducing HSCs self-renewal and thus HSCs expansion. In this study، we tried to enhance self-renewal of cord blood HSCs by HOXB4 overexpression during ex vivo expansion period. In this fundamental-applied research، HSCs were transducted by lentiviral vectors containing HOXB4. HSCs were then cultured in IMDM medium containing 10% FBS and early acting cytokines (Flt3L، SCF، Tpo) for 8 days. Thereafter، we evaluated HOXB4 expression by RT-PCR. The CD34+ subpopulation were also examined by flow cytometry. We detected a high level of HOXB4 gene expression in HOXB4 transducted HSCs relative to the control. We observed that HOXB4 over-expression dramatically increases CD34+ subpopulation of HSCs. The increase in the number of CD34+ HSCs is an indicator of HSCs self-renewal during ex vivo expansion period. All in all، in this survey we observed that HOXB4 overexpression markedly increases CD34+ HSCs during ex vivo expansion period. This approach can be very effective for overcoming the limited number of cord blood HSCs for cell therapy purposes.