Investigation of E-cadherin-mediated Mechanosensing on Different Microstructures

Abstract

Effects of mechanical stiffness in the cell niche has typically been evaluated via modulating ECM stiffness. However, cellular stiffness may also play an important role in various cellular processes, as cell junction proteins such as beta-catenin can function both as a mechanosensor and a signalling protein. Using multiphoton fabrication, we studied the effects of modulus and 3D mechanical confinement with E-cadherin coated substrates on cell fates. Cells were seeded onto two types of structures: flat matrix structures which presented E-cadherin only, or a 3D checkerboard structure with laminin on the base and E-cadherin on the sides to observe monolayer formation and fidelity. On the E-cadherin coated flat matrix structures, beta-catenin spreading was observed to correlate with F-actin differently in low- and high- modulus conditions. On high-modulus E-cad substrates, diffuse beta-catenin was observed and actin localization was observed at protrusions. On low-modulus E-cad substrates, cells exhibited sporadic spikes or puncta of beta-catenin that co-localized with actin spikes. On the checkerboard structures, cells spread and were rounded, filling up the space on the structures. Compared to laminin-only controls, E-cadherin and beta-catenin staining had lower intensity. This suggests that cells may regulate cadherin expression when exposed to 3D mechanical confinement with apicobasal cues. Combined, these results improve our understanding of mechanosensing at E-cadherin junctions, as a first step to understanding the role of cell stiffness in processes such as EMT and epithelial cell development.