A method for isolating pluripotent/multipotent stem cells from blood by using the pluripotent and germ-line DAZL gene as a marker

We have shown for the first time that pluripotent/multipotent stem cells can be isolated from blood in a relatively simple cell separation, which is fast and compatible with current standards. We used the germ line- and pluripotent-specific DAZL gene as a marker to demonstrate its use for identifying and isolating pluripotent/multipotent cells from blood. DAZL-expressing (DE) cells were identified in about 0.3 of umbilical cord blood (UCB) mononuclear cells. These DE cells do not express either blood cell differentiation markers, such as CD38, CD3, and CD14, or the blood progenitor cell markers, such as CD34 and CD133. Nevertheless, they express pluripotent embryonic stem (ES) cells OCT-4 and SOX-2 genes. To examine whether the DE cells exhibit stem cell characteristics, we seeded 10³ DE cells in methylcellulose containing the ingredients needed for hematopoietic cell growth. Although DE cells are CD34-, a mean (±SD) of 21 ± 4 colonies were formed per plate, of which 4.8 were colony-forming unit granulocyte, erythroid, macrophage, megakaryocytes (CFU-GEMMs). Mononuclear or CD34+ cells isolated from UCB formed 6 ± 1 and 53 ± 8 colonies per plate, respectively, of which 0 and 3.8 were CFU-GEMMs. DE cells grown in methylcellulose without cytokines formed various colonies, which demonstrated expression pattern that is typical of neurons, endothelial, bone/cartilage, cardiomyocyte, and hepatocyte differentiation as determined by reverse transcriptase-PCR (RT-PCR). Our results suggest that DE cells, which possess some pluripotent/multipotent characteristics of ES cells, can be easily isolated from blood. These cells may be effective in various therapeutic applications with no biological or ethical ramifications.