3D Co-culture Model on the Role of Vimentin in Notch Signaling and Vascularization

The Notch signaling pathway is a conserved pathway that is central in vascular tissue development and pathology. Because this pathway controls such important events, it is regulated at multiple steps of its cascade, such as post-translational modification of its ligand and receptor. Recent studies have suggested regulation of the Notch signaling by a pulling force to be required to activate Notch signaling. In this exploratory study, 3D fibrin gels were used as a co-culture system of endothelial cells and 10T1/2 cells to assess whether vimentin is implicated in the regulation of Notch signaling and neovascularization. The results show that 10T1/2 cells increase the expression of Hes-1, Hes-5, and Acta2 during co-culture with human coronary artery endothelial cells (HCAECs) and that vimentin knock-down using siRNA partially reduced the expression under static conditions. On the other hand, while the same trend was observed for Hes-5 under dynamic conditions, Acta2 was overexpressed, and vimentin knock-down did not affect its expression levels. Moreover, the development of newly formed micro-vessels is observed in 3D fibrin gels in the presence of VEGF but could not be formed when vimentin expression was knocked down. These results suggest that vimentin plays a secondary role in Notch signaling; however, it is essential for neovascularization.