Small Peptide Analogue of SDF-1 alpha Supports Survival of Cord Blood CD34 super(+) Cells in Synergy with Other Cytokines and Enhances Their Ex Vivo Expansion and Engraftment into Nonobese Diabetic/Severe Combined Immunodeficient Mice

The SDF-1/CXCR4 axis has been implicated in the chemotaxis, homing, mobilization, and expansion of hematopoietic stem and progenitor cells. We studied the effects of a SDF-1 peptide analogue CTCE-0214 on the survival of cord blood CD34 super(+) cells in culture, expansion, and engraftment of expanded cells in the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model. Our results demonstrated that CTCE-0214 synergized with thrombopoietin (TPO), stem cell factor (SCF), or flt-3 ligand (FL) on the survival of stem and progenitor cells in culture. Adding CTCE-0214 at a low concentration (0.01 ng/ml) for 4 days together with TPO, SCF, and FL significantly enhanced ex vivo expansion of CD34 super(+) cells to subsets of primitive (CD34 super(+)CD38 super(-) cells, colony-forming unit-mixed [CFU-GEMMs]), erythroid (CFU-Es), myeloid (CFU-GMs), and megakaryocytic (CD61 super(+)CD41 super(+) cells, CFU-MKs) progenitors, as well as their multilineage engraftment in NOD/SCID mice. Interestingly, the short exposure of expanded cells to CTCE-0214 (100 and 500 ng/ml) for 4 hours did not increase the quantity of progenitor cells but enhanced their engraftment capacity. The proportion of CD34 super(+) cells expressing surface CXCR4 was decreased, but the overall number of this population increased upon expansion. The small peptide analogue of SDF-1 could be developed for ex vivo expansion and improving engraftment of cord blood transplantation.