Communication of substance P, calcitonin-gene-related neuropeptides and chemokine receptor 4 (CXCR4) in cord blood hematopoietic stem cells.

BACKGROUND Modulation of the expression of CXCR4 as a critical adhesion molecule on cord blood (CB) CD34+ cells could overcome delay following cord blood transplantation. Identification of beneficial effects of growth factors including cytokines and neuropeptides on CXCR4 expression would enable our understanding of this complicated network. Therefore, we aimed to assess the role of substance P (SP) and Calcitonin gene related peptide (CGRP) on CXCR4 levels. MATERIAL AND METHODS CD34+cells purified from CB were cultured in a serum-free liquid culture system. Different concentrations of SP and CGRP were used in combination with cytokine cocktail. Expression of CXCR4 at protein and genomic levels was assessed by flow cytometry and real time RT-PCR. RESULTS Our results indicate increased CXCR4+ CD34+ cells after 7 days cultivation with SP and/or CGRP. Increased gene expression of the CXCR4 molecule was observed at 10(-9) M either SP or CGRP individually, by day 11 as compared to control group. CONCLUSIONS Our study indicates that SP and CGRP induce CXCR4 protein expression in short term culture, and stimulate its expression. Consequently, the increased expression of CXCR4 could improve engraftment of CB CD34+ cells.