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 selfrenewal 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 (RTPCR) 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-ACLDL 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 4(th) to 11(th). 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.