Adaptation of endothelial cells to microenvironment topographical cues through lysyl oxidase like-2-mediated basement membrane scaffolding

Abstract

Basement membrane (BM) provides structural support and signaling platform for blood vessels. While its major structural components are required for vascular morphogenesis, integrating BM regulators, like the lysyl oxidase LOXL2, and BM assembly in cell response to microenvironement cues remain poorly understood. Here we study the early deposition and supramolecular assembly of BM components using correlative atomic force and fluorescence microscopy. The fibrillar deposition of fibronectin is gradually remodeled and associates with the collagen IV meshwork as it organizes into BM. We demonstrate that LOXL2 is deposited with both proteins and participates in their remodeling. Alteration of BM scaffolding by LOXL2-depletion affects focal adhesion maturation and cytoskeleton remodeling. This altered BM organization maintains stress fibers, affects the distribution and activation of mechanosensors and alters cell barrier properties. Furthermore, using 3D micro-printed substrates, we demonstrate that BM assembly regulates endothelial cell response to topographical constraint. We therefore propose a mechanism directly linking the scaffolding of BM components and adaptation to the topographical signals from the microenvironment.