Evaluating The Expression of Self-Renewal Genes in Human Endothelial Progenitor Cells

Objective: Endothelial progenitor cells (EPCs) have a potential application for cell therapy, however, their biological nature is not well-understood. EPCs also possess some stemness features, such as their clonogenicity and differentiation capacity. The main aim of this study was to evaluate the expression of certain transcription factors regulating self-renewal property of stem cells. Materials and Methods: In this experimental study, peripheral blood mononuclear cells were isolated from fresh human blood of several volunteers and were cultured in fibronectin- coated plates. EPCs were identified based on their morphology and growth characteristic. Then, the expression of some markers implicated in self-renewal capacity was assessed in the isolated cells using reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry. Results: Expression of the cell surface markers, CD31 and CD34, was determined by RT-PCR and immunocytochemistry. Furthermore, these cells had the ability for Di-AC-LDL incorporation as well as attachment to lectin I. EPCs did not express the main stem cell markers, like OCT4-A, Nanog, and Sox2; nevertheless, they expressed the weaker pluripotent markers, including OCT4B and OCT4-B1 spliced variants, such as Nucleostemin and ZFX. Furthermore, the expression of Nucleostemin and ZFX genes revealed a decreasing pattern from days 4th to 11th. Conclusion: The main regulators of stem cell self-renewal genes, including OCT4-A, Nanog, and Sox2 are not expressed in EPCs. Forced expression of these genes can elevate the stemness property and clinical application of EPCs.