[Differential expression of proteins in rat mesenchymal stem cells undergoing endothelial differentiation].

Objective: To screen and identify differentially expressed proteins of mesenchymal stem cells (MSC) during endothelial differentiation.

Methods: MSCs were induced to endothelial differentiation with vascular endothelial growth factor (VEGF) and epithelial growth factor (EGF) mixture. The whole cell proteins were extracted and isolated by two-dimensional gel electrophoresis. After gel was analyzed by Imagemaster 5.0 software, differentially expressed proteins were partially selected and identified by MALDI-TOF-MS.

Results: The differentiated MSC highly expressed endothelial cells related markers, CD31, CD34 and FVIIIAg were 56.8%, 38.8% and 14.5% respectively by flow cytometer. Compared with the primary cultured MSC, the differentiated cells differentially expressed 91 proteins. Among the 19 identified proteins, 11 up-regulated and 8 down-regulated, which include cytoskeletal proteins, such as myosin, filamin, vimentin and vinculin; cell metabolism enzymes, such as ORP-150, ERO1-α, Delta(3,5)-Delta(2,4)-dienoyl-CoA isomerase, protein disulfide-isomerase A3, FAS and enolase 3; nuclear factors, such as TAR DNA binding protein, guanine nucleotide binding protein and hypoxia up-regulated protein 1; VEGF receptors, such as KDR and so on.

Conclusions: Cytoskeletal proteins, metabolism enzymes and KDR were all involved in endothelial differentiation of MSC. These proteins may be the regulatory targets for endothelial differentiation of MSC.