title: R-Smad signaling-mediated VEGF expression coordinately regulates endothelial cell differentiation of rat mesenchymal stem cells.
abstract: A low-efficiency yield hinders the use of stem cells as a source of endothelial cells (ECs) for therapeutic vascularization, and the diversity of the transforming growth factor-β (TGF-β) superfamily has undermined understanding the effects of its potent vascularization-inducing. Herein, we studied the role of the TGF-β superfamily in EC differentiation of rat bone marrow mesenchymal stem cells (MSCs) induced by Smad2/3 and Smad1/5/8 signaling. MSCs that had been sorted by flow cytometry as CD31-negative were cultured for 14 days in medium supplemented with vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) as the control. The Smad2/3 pathway was activated by TGF-β1 and Smad1/5/8 by bone morphogenetic proteins (BMPs). In the early phase in the Smad2/3-activated group, there were 10% CD31-positive cells, which was significantly higher than in the control group. A low Smad1/5/8 phosphorylation level after BMP4 activation doubled the number of CD31-positive cells, while a higher phosphorylation level after BMP9 activation showed no effect. A Smad2/3 inhibitor initially blocked differentiation but later promoted it, while a Smad1/5/8 inhibitor reversed the induction observed with BMPs. Moreover, the positive effects of R-Smad on differentiation were weakened by the VEGF neutralizing antibody, and a Smad3 inhibitor decreased VEGF expression and blocked differentiation in both the early and late phases. In conclusion, differentiation of ECs from MSCs via Smad2/3 signaling is stage dependent. Activation, particularly by Smad3, significantly promotes differentiation at an early phase but later is suppressive. A low Smad1/5/8 phosphorylation level has a positive effect, and R-Smad effects are partly mediated by VEGF.
authors.affiliation: 1Vascular Surgery Division, Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.|2Vascular Surgery Division, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Ai
authors.affiliation: 2Vascular Surgery Division, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: 1Vascular Surgery Division, Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
authors.forename: Shao-Mang
authors.initials: SM
authors.lastname: Lin
authors.affiliation: 3Laboratory of General Surgery, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: 2Vascular Surgery Division, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Chi-Zhuai
authors.initials: CZ
authors.lastname: Liu
authors.affiliation: 2Vascular Surgery Division, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Lv
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D055429:Growth Differentiation Factor 9 / Q000235:genetics / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D051896:Smad Proteins, Receptor-Regulated / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D055429:Growth Differentiation Factor 9; D051896:Smad Proteins, Receptor-Regulated; D042461:Vascular Endothelial Growth Factor A