GSK-3β inhibition promotes early engraftment of ex vivo- expanded haematopoietic stem cells

Cell Proliferation (Impact Factor: 3.12). 02/2014; 47(2). DOI: 10.1111/cpr.12092
Source: PubMed


Umbilical cord blood (UCB) is a source of stem cells used for allogeneic transplantation, in addition to bone marrow and peripheral blood. Limited numbers of stem cells in a single UCB unit is associated with slow haematopoietic recovery and high risk of graft failure, particularly in adult patients. UCB stem cells can be expanded ex vivo; however, rapid differentiation reduces their regenerative potential. We have recently shown that Wnt/β-catenin signalling is down-regulated in ex vivo-expanded stem cells; therefore, we propose that re-activation of Wnt signalling using GSK-3β inhibition may act to improve regenerative potential of these ex vivo-expanded stem cells.
Immunocompromised mice were employed in transplantation studies to determine stem-cell engraftment. Flow cytometry was used to phenotype the engrafted human cells. Retroviral gene transfer was used to examine the role of Myc gene up-regulated by GSK-3β inhibition, in ex vivo-expanded stem cells.
Treatment with GSK-3β inhibitor, 6-bromoindirubin 3'-oxime (BIO) improved early human cell engraftment in the mice and elevated the numbers of myeloid progenitor cells in cytokine-stimulated culture. BIO up-regulated β-catenin and c-myc in ex vivo-expanded stem cells. Ectopic expression of Myc acted to increase clonogenic potential and to delay differentiation of haematopoietic progenitor cells, suggesting the potential mechanism to improve regenerative potential of ex vivo-expanded grafts.
Pharmacological inhibition of GSK-3β provided a novel approach to improve early engraftment of ex vivo-expanded haematopoietic progenitor cells.

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    • "In this regard, it was reported that Wnt1 signaling could stimulate ex vivo expansion of CB by enhancing HSC proliferative properties and by stabilizing the expression of pluripotency and self-renewal genes (Chotinantakul et al., 2013). Other studies have shown that GSK-3beta inhibitors determine an activation of Wnt signaling, an expansion of HSCs and improved early human cell engraftment in nude mice (Dolnikov et al., 2014). In addition to Wnt, the NOTCH signaling pathway is of fundamental importance in the control of HSC self-renewal: in fact, ex vivo culture of CD34 þ CB stem/progenitor cells in the presence of NOTCH ligand resulted in a greater than 100-fold increase in CD34 þ cells repopulating immunodeficient mice (Delaney et al., 2010). "
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