Umbilical Cord Blood Cells Express mRNA for Neuronal Genes MAP2 and NEFL.

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.

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NEFL in Peripheral Blood (PB)

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NEFL in Peripheral Blood (PB)

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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.