Increase of CXCR4 Expression on Expanded Non-enriched Cord Blood CD34+ Cells Using MSCs

Introduction: A number of potential cell adhesion molecules, which mediate essential cell-to-cell or cell-to-matrix interactions, are expressed on the surface of CD34+ hematopoietic progenitor cells (HPCs), including integrins, CD44, and CXCR4. These molecules are essential for homing process. In this study, we compared the changes of expression of CD44 and CXCR4 on the CD34+ hematopoietic progenitor cells expanded on MSCs in the presence of cytokines. Material and Methods: Cord blood CD34+ cells were expanded using human bone marrow mesenchymal stem cells and cytokines (TPO, SCF, FLt-3, IL-6, and IL-3), and then expression of CD44 and CXCR4 on CD34+ cells were evaluated by flow cytometric analysis. Results: After 2 weeks of serum free culture of CD34+ cells in the presence of cytokines, the expression of CXCR4 on CD34+ cells was decreased 3.4 fold (p < 0.05). In contrast, the expression of CXCR4 on CD34+ cells expanded on hMSCs was increased (p < 0.05). The expression of CD44 on expanded CD34+ cells in both methods did not differ significantly. Conclusions: Our results indicated that co-culture of cord blood stem cells on hMSCs significantly increased CXCR4 expression on cord blood CD34+ cells.