Blood flow and endothelial cell phenotype regulation during sprouting angiogenesis.

The role of the endothelial cell environment and shear stress induced by blood flow in phenotype determination and lumen formation has been clearly illustrated in recent studies. In the present work, a model is developed to map environmental and flow induced signals in sprouting angiogenesis to endothelial cell phenotype and lumen formation. To follow the endothelial cell lumen formation, its signaling pathway is incorporated in the present work within the phenotype determination pathway that has been recently utilized to model endothelial cell migration, proliferation, and apoptosis. Moreover, a signaling cascade for shear stress activation of endothelial cells is proposed and used for phenotype determination with activation of blood flow. A Boolean network model is employed to build a hybrid map for the relation between the endothelial cell environmental signals and the endothelial cell fate in sprouting angiogenesis with and without blood flow. This map is very useful in the development of models for sprouting angiogenesis. Moreover, this study shows that inhibition of intracellular signaling molecules, solely or in pairs, blocks angiogenic-signaling pathways and can be used to inhibit angiogenesis.