Hydrogel Network Dynamics Regulate Vascular Morphogenesis

Matrix dynamics influence how individual cells develop into complex multicellular tissues. Here, we develop hydrogels with identical polymer components but different crosslinking capacities to enable the investigation of mechanisms underlying vascular morphogenesis. We show that dynamic (D) hydrogels increase the contractility of human endothelial colony-forming cells (hECFCs), promote the clustering of integrin β1, and promote the recruitment of vinculin, leading to the activation of focal adhesion kinase (FAK) and metalloproteinase expression. This leads to the robust assembly of vasculature and the deposition of new basement membrane. We also show that non-dynamic (N) hydrogels do not promote FAK signaling and that stiff D- and N-hydrogels are constrained for vascular morphogenesis. Furthermore, D-hydrogels promote hECFC microvessel formation and angiogenesis in vivo. Our results indicate that cell contractility mediates integrin signaling via inside-out signaling and emphasizes the importance of matrix dynamics in vascular tissue formation, thus informing future studies of vascularization and tissue engineering applications. [Display omitted] •Development of dynamic hydrogels to study matrix dynamics role in vascular assembly•Dynamic hydrogels promote cell contractility-mediated integrin clustering•Non-dynamic hydrogels prevent integrin clustering, subsequently inhibiting morphogenesis•Dynamic hydrogels promote the formation of microvessels and angiogenesis in vivo Engineered viscoelastic hydrogels with dynamic crosslinks permit cell contractility-mediated integrin clustering and FAK activation, independent of hydrogel stiffness, and promote vascular assembly. However, non-dynamic hydrogels prevent cell contractility and integrin clustering, subsequently inhibiting the initiation and progression of vascular morphogenesis.