Minicircle-based expression of vascular endothelial growth factor (VEGF) in mesenchymal stromal cells (MSC) from diverse human tissues.

BACKGROUND Mesenchymal stromal cells (MSC) have been exploited for the treatment of ischemic diseases given their angiogenic potential. Despite bone marrow (BM) being the most studied tissue source, cells with similar intrinsic properties can be isolated from adipose tissue (AT) and umbilical cord matrix (UCM). This study aims to compare the angiogenic potential of MSC obtained from BM, AT and UCM that were genetically modified with VEGF-encoding minicircle vectors. The overexpression of VEGF combined with the intrinsic properties of MSC could represent a promising strategy towards angiogenic therapies. METHODS We established a microporation-based protocol to transfect human MSC using VEGF-encoding minicircles (MC-VEGF). VEGF production levels were measured by ELISA and quantitative PCR. The in vitro angiogenic potential of transfected cells was quantified using cell tube formation and migration functional studies. RESULTS MSC isolated from BM, AT or UCM showed similar levels of VEGF secretion after transfection with MC-VEGF. Those values were significantly higher when compared to non-transfected cells, indicating an effective enhancement of VEGF production. Transfected cells displayed higher in vitro angiogenic potential than non-transfected controls, as demonstrated by functional in vitro assays. No significant differences were observed among cells from different sources. CONCLUSIONS Minicircles can be successfully used to transiently overexpress VEGF in human MSC, regardless of the cell tissue source, representing an important advantage in a clinical context (i.e. angiogenic therapy) since a standard protocol might be applied to MSC of different tissue sources, which can be differentially selected according to the application (e.g. autologous versus allogeneic settings).