Journal of Stem Cell Research & Therapy

Abstract

In Vitro Characterization of the Molecular Machinery Regulating Umbilical Cord Blood Mesenchymal Stem Cell Angiogenesis: A Step Towards Multipotent Stem Cell Therapy for Vascular Regeneration

Santiago Roura, Juli R Bagó, Carolina Gálvez-Montón, Jerónimo Blanco and Antoni Bayes-Genis

Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) promote vascular growth in vivo. Here we examined the intracellular regulatory machinery involved in the in vitro angiogenic behaviour exhibited by UCBMSCs. Angiogenic activity was measuring in the standard Matrigel-based culture assay after treatment of cells with known modulators of early growth response factor (Egr-3) and endothelial cell (EC) angiogenesis. Egr-3 expression was assessed by quantitative RT-PCR and indirect immunofluorescence, and specifically abrogated using small interfering RNA (siRNA) technology. While addition of phorbol-12-myristate-13-acetate (PMA) promoted angiogenic capacity (P<0.001), selective inhibitors of PKC/MAPK/ERK abrogated this capacity (P=0.016) in UCBMSCs. Treatment with PMA increased Egr-3 mRNA and protein levels (P<0.001). However, cyclosporine A (CsA) and vascular endothelial growth factor (VEGF) affected neither Egr-3 levels nor the formation of polygonal cell networks. PMA also induced ERK1/2 phosphorylation, which was abolished by the selective inhibitor U0126 (P=0.021 and P=0.014, respectively). Marked inhibition of network-forming capacity was observed in siEgr-3-transduced cells (P<0.001). Taken together, our results highlight that Egr-3 is commonly involved in the molecular machinery regulating mature EC and multipotent MSC angiogenesis. This knowledge may be applied to increase therapeutic efficacy against human vascular diseases.