Hematopoietic tissue-derived cells including stem cells have been shown to differentiate into or fuse with solid organ tissue-specific cells. Among hematopoietic tissue cells, umbilical cord blood (UCB)-derived stem cells have the advantage of a higher engraftment potential. It was the purpose of this study to gather evidence on a molecular level of UCB-derived cells and stem cells generating or fusing with solid-organ tissue specific cells such as CNS-specific cells as a model for potential treatment of injured tissue.
Fresh UCB was obtained by standard UCB banking procedures. Apheresis-derived mononuclear cells (adult MNC) were obtained from normal stem cells donors who underwent a 4-day G-CSF mobilization treatment. UCB cells (4 individual UCB harvests) and adult MNC (4 individuals) were selected for CD133/1+ or CD14+ or CD3+ cells by immunomagnetobead separation (autoMACS; Miltenyi Biotec). Each specimen contained between 8 and 20 × 106 selected cells at a purity of >90%.
Real-time PCR was performed on the ABI Prism 7900 using the Assays-on-Demand for various neuronal genes such as Neurofilament (NEFL), Microtubule-associated protein 2 (MAP2), βTubulin 3 (TUBB3) and Nestin (NES), and the cylophilin Pre-Developed Assay Reagent (Applied Biosystems) without multiplexing. The ddCt method was used to calculate fold-difference in neuronal gene expression in the cell specimens relative to Stratagene’s normal lymph node RNA.
Neuronal cell-specific NEFL and MAP2 expression was found in both, UCB and adult MNC, but not TUBB3 or NES expression. The MAP2 expression was in favor of CD133−, CD14− and CD3− selected cells, whereas NEFL expression was significantly higher in CD3+ selected cells as compared with CD3− cells in both, UCB cells and adult MNC.
These preliminary results indicate that UCB and mobilized adult blood contain cell subsets that express mRNA for neuronal cell specific genes. NEFL expression seems to be higher in CD3-selected cells, whereas MAP2 and NEFL gene expression in progenitor cell subsets (CD133+) was found to be less.
As shown by us in a clinical sex-mismatched UCB transplant setting and by others hematopoietic tissue-derived neuronal-like cells are identified in CNS tissue. Circulating cells expressing neuronal-specific genes could contribute to homeostasis of CNS tissue as known for the hematopoietic tissue.
Disclosure: No relevant conflicts of interest to declare.