Bone marrow-derived mesenchymal stem cells (MSCs) have the potential to differentiate into mesenchymal tissues like osteocytes, chondrocytes, and adipocytes in vivo and in vitro. Evidence is emerging that protein kinases, the members of a large family of proteins involved in modulating many known signaling pathways, are likely to play important roles in regulating stem cell self-renewal and differentiation programs but also inhibition of GSK-3棺 promote some precursor cells to differentiate into endothelial cells. The aim of this study was to investigate the in vitro differentiation of MSCs into cells of the endothelial lineage through regulation of GSK-3棺. Differentiation into endothelial-like cells was induced by cultivation of cells in the presence of GSK-3棺 inhibitor for 16 days. In sandwich ELISA, the expression of endothelial-specific markers (CD31) was elevated dose-dependently (0.1-1 關M). RT-PCR analysis of the differentiated cells showed a strong increase of expression of endothelial-specific markers like eNOS, VE-cadherin, VCAM-1 and VEGF-R2, and immunofluorescence analysis showed typical expression of the von Willebrand factor. The functional behavior of the differentiated cells was tested with an in vitro angiogenesis test kit where cells formed characteristic capillary-like structures. We could show the differentiation of MSCs into cells with phenotypic and functional features of endothelial cells. The differentiation of MSCs into endothelial cells by the treatment of GSK-3棺 inhibitor was associated with phosphorylation of GSK-3棺 and dephosphorylation of 棺-catenin and the expression level of 棺-catenin on 16 days when the differentiation direction was determined, was lower than that on 0-13 days. The current study suggests that the regulation of protein kinase may emerge as a remarkable tool for the differentiation of MSCs. These pre-differentiated cells provide new options for engineering of artificial tissues based on autologous MSCs and vascularized engineered tissues.