Distinct contact guidance mechanisms in single endothelial cells and in monolayers

Abstract

In many tissues, cell shape and orientation are controlled by a combination of internal and external biophysical cues. Anisotropic substrate topography is a ubiquitous cue that leads to cellular elongation and alignment, a process termed contact guidance, whose underlying mechanisms remain incompletely understood. Additionally, whether contact guidance responses are similar in single cells and in cellular monolayers is unknown. Here, we address these questions in vascular endothelial cells (ECs) that in vivo form a monolayer that lines blood vessels. Culturing single ECs on microgrooved substrates that constitute an idealized mimic of anisotropic basement membrane topography elicits a strong, groove depth-dependent contact guidance response. Interestingly, this response is greatly attenuated in confluent monolayers. While contact guidance in single cells is principally driven by persistence bias of cell protrusions in the direction of the grooves and is surprisingly insensitive to actin stress fiber disruption, cell shape and alignment in dense EC monolayers are driven by the organization of the basement membrane secreted by the cells, which leads to a loss of interaction with the microgrooves. The findings of distinct contact guidance mechanisms in single ECs and in EC monolayers promise to inform strategies aimed at designing topographically patterned endovascular devices.

Microgroove substrates unveil topography-driven, dynamic 3D nuclear deformations

“…We have recently studied the mechanisms underlying contact guidance in human umbilical vein endothelial cells (HUVECs) cultured on fibronectin-coated polydimethylsiloxane (PDMS) microgrooves (Fig. 1A) (Leclech et al, 2023). In the course of these investigations, we came across the observation that for a microgroove depth of ~5 µm, the cell nuclei exhibited significant out-of-plane deformation and penetration into the grooves, in addition to the planar nuclear elongation and alignment associated with contact guidance (Fig.…”

“…In this context, we have been using microgroove substrates as idealized models of the anisotropic subcellular topography of the vascular basement membrane . Our recent studies using these substrates have demonstrated their ability to control vascular endothelial cell morphology, cytoskeletal organization, and collective migration (Leclech et al, 2022(Leclech et al, , 2023.…”