Endothelial Basement Membrane Laminins as an Environmental Cue in Monocyte Differentiation to Macrophages.

Monocyte differentiation to macrophages is triggered by migration across the endothelial barrier, which is constituted by both endothelial cells and their underlying basement membrane. We address here the role of the endothelial basement membrane laminins (laminins 411 and 511) in this monocyte to macrophage switch. Chimeric mice carrying CX3CR1-GFP bone marrow were employed to track CCL2-induced monocyte extravasation in a cremaster muscle model using intravital microscopy, revealing faster extravasation in mice lacking endothelial laminin 511 ( ) and slower extravasation in mice lacking laminin 411 ( ).

The role of basement membrane laminins in vascular function.

The extracellular matrix is an integral component of the vasculature, contributing to both developmental processes and structural and functional homeostasis. We describe here the types of extracellular matrices that occur in different blood vessel types, ranging from capillaries to veins, venules and arteries, and focus on the endothelial basement membranes and the laminin family of proteins. We summarize data on the molecular composition of endothelial basement membranes, the structure and in vivo expression patterns of the main endothelial laminin isoforms (laminins 411 and 511) and their, to date, deciphered functions in the vasculature.

Signals of the Neuropilin-1-MET Axis and Cues of Mechanical Force Exertion Converge to Elicit Inflammatory Activation in Coherent Endothelial Cells.

The neuropilin-1 (NRP1)-MET signaling axis regulates the motility of individual endothelial cells (ECs). It is unknown how this signaling pathway affects the endothelial barrier in coherent ECs forming a tight monolayer. We hypothesized that it is involved both in modulation of the endothelial barrier and in EC activation.

Endothelial basement membrane laminin 511 is essential for shear stress response.

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Endothelial basement membrane laminin 511 is essential for shear stress response.

Shear detection and mechanotransduction by arterial endothelium requires junctional complexes containing PECAM-1 and VE-cadherin, as well as firm anchorage to the underlying basement membrane. While considerable information is available for junctional complexes in these processes, gained largely from in vitro studies, little is known about the contribution of the endothelial basement membrane. Using resistance artery explants, we show that the integral endothelial basement membrane component, laminin 511 (laminin α5), is central to shear detection and mechanotransduction and its elimination at this site results in ablation of dilation in response to increased shear stress.