2022, Vol. 26 ›› Issue (31): 4946-4953

Vascular endothelial growth factor-Notch signaling pathways in endothelial precursor cells in promoting the transformation of bone marrow mesenchymal stem cells into hepatocyte-like cells

Yu Yunbao1, 2, Chen Lin1, 2, Wu Xiya3, Yan Lerong3, Miao Zhang3, Man Yang3, Jing Renyi3, Lei Zhen1, Chu Zhiqiang1, Zhang Hongwei1, 4   

Abstract: BACKGROUND: Previous studies have shown that endothelial precursor cells produced factors that could promote bone marrow mesenchymal stem cells differentiation by paracrine in vitro, and vascular endothelial growth factor was one of them.  
OBJECTIVE: To investigate whether vascular endothelial growth factor-Notch signaling pathway participates in the way that endothelial precursor cells promote the transformation of bone marrow mesenchymal stem cells to hepatocyte-like cells.
METHODS: (1) Bone marrow mesenchymal stem cells and endothelial precursor cells of Sprague-Dawley rats were isolated and cultured. The bone marrow mesenchymal stem cells at passage 3 were divided into three groups. In the experimental group, the serum-free and factor endothelial precursor cells-conditioned medium was mixed with hepatocyte transformation medium in a volume ratio of 1:1. In the model control group, serum-free alpha-minimal essential medium was mixed with the hepatocyte transformation medium in a volume ratio of 1:1. In the blank control group, normal alpha-minimal essential medium was used. The expression levels of alpha-fetoprotein and albumin were detected by immunofluorescence at 3, 5, 7, and 9 days of culture. (2) The third generation of bone marrow mesenchymal stem cells was taken to transform into hepatocyte-like cells and grouped. The serum-free and factor endothelial precursor cells-conditioned medium, vascular endothelial growth factor, and serum-free and factor vascular endothelial growth factor-siRNA-endothelial precursor cells-conditioned medium were added in hepatocyte transformation medium in a volume ratio of 1:1. In the control group, the samples were cultured with the hepatocyte transformation medium. At 48 hours after culture, the expression changes of Dll4, Hes1, and Hey1 (downstream gene of Notch) in bone marrow mesenchymal stem cells were detected by RT-PCR and western-blot assay.  
RESULTS AND CONCLUSION: (1) Alpha-fetoprotein and albumin were not found in the blank control group. Alpha-fetoprotein and albumin levels were increased in the model control group and the experimental group (P < 0.05), and alpha-fetoprotein and albumin levels were significantly increased in the experimental group compared with the model control group (P < 0.05). (2) After adding serum-free and factor endothelial precursor cells-conditioned medium or vascular endothelial growth factor, the expression of Dll4 and Hey1 protein and mRNA increased (P < 0.05), but the expression of Hes1 protein and mRNA decreased (P < 0.05). After adding serum-free and factor vascular endothelial growth factor-siRNA-endothelial precursor cells-conditioned medium, the expression of Dll4 and Hey1 protein and mRNA decreased, and the expression of Hes1 protein and mRNA increased (P < 0.05). (3) The results show that the bone marrow endothelial precursor cells may play a certain role in the transformation of bone marrow mesenchymal stem cells into hepatocyte-like cells, and the vascular endothelial growth factor-Notch signaling pathway may be involved in this process.
Key words: bone marrow mesenchymal stem cell, endothelial precursor cell, vascular endothelial growth factor, Notch signaling pathway, hepatocyte-like cell