Nanomanipulation of Ligand Nanogeometry Modulates Integrin/Clathrin-Mediated Adhesion and Endocytosis of Stem Cells

Nanosubstrate engineering can be a biomechanical approachfor modulatingstem cell differentiation in tissue engineering. However, the studyof the effect of clathrin-mediated processes on manipulating thisbehavior is unexplored. Herein, we develop integrin-binding nanosubstrates with confined nanogeometries that regulate clathrin-mediated adhesion-or endocytosis-active signaling pathways for modulating stem fates.Isotropically presenting ligands on the nanoscale enhances the expressionof clathrin in cells, thereby facilitating uptake of dexamethasone-loadednanoparticles (NPs) to boost osteogenesis of stem cells. In contrast,anisotropic ligand nanogeometry suppresses this clathrin-mediatedNP entry by strengthening the association between clathrin and adhesionspots to reinforce mechanotransduced signaling, which can be abrogatedby the pharmacological inhibition of clathrin. Meanwhile, inhibitingfocal adhesion formation hinders cell spreading and enables a higherendocytosis efficiency. Our findings reveal the crucial roles of clathrinin both endocytosis and mechanotransduction of stem cells and providethe parameter of ligand nanogeometry for the rational design of biomaterialsfor tissue engineering.

Automated summary

Nanosubstrate engineering can modulate stem cell differentiation in tissue engineering through biomechanical means. The effect of clathrin-mediated processes on this behavior has not been explored. In this study, we developed integrin-binding nanosubstrates with confined nanogeometries to regulate clathrin-mediated signaling pathways for modulating stem fates. Isotropic ligand presentation on the nanoscale enhanced clathrin expression and facilitated uptake of dexamethasone-loaded nanoparticles, promoting osteogenesis. In contrast, anisotropic ligand nanogeometry suppressed clathrin-mediated nanoparticle entry and reinforced mechanotransduced signaling by strengthening the association between clathrin and adhesion spots. Inhibiting focal adhesion formation hindered cell spreading and increased endocytosis efficiency.