Insights on the receptor dynamics during the spreading of endothelial cells

Multi-physics interactions preside the ligand-dependent relocation of the vascular endothelial cell (VEGFR2) receptor in the lipid membrane of endothelial cells (ECs) [1– 3]. In spite using a surrogated mechanics allowed identifying limiting factors of the evolution in time of quantities of interest with significant accuracy, the quantification of mechanical measures remained questionable. In the present work, VEGFR2 receptor dynamics is coupled to large strain mechanics to simulate the relocation of proteins on endothelial cells. Fully coupled mass and momentum balance laws, accompanied by thermodynamically derived constitutive laws, are written in weak form and discretized via the finite element method. High performance computations are carried out afterwards, making use of the open-source library deal.ii (dealii.org). In vitro ECs adhesion assay on a Poly-Lysine substrate validated the numerical simulations. Poly-Lysine is a positively charged amino acid polymer. Poly-Lysine promotes cell adhesion to solid substrates by enhancing electrostatic interaction between negatively charged ions of the cell membrane in the absence of the cytoskeleton assembly. We developed a mechanical models for the geometrical evolution of the cell membrane in the absence of cytoskeleton reorganization, accounting for the passive mechanical response of the cell only. This selective, co-designed approach in experiments and modeling allows shading new insights on both the receptor dynamics and the physical mechanisms that govern cell adhesion and spreading.