Stiffness-Induced Endothelial DLC-1 Expression Forces Leukocyte Spreading through Stabilization of the ICAM-1 Adhesome

• Published in: Cell reports (Cambridge) 2018-09, Vol.24 (12), p.3115-3124
• Main Authors: Schimmel, Lilian, van der Stoel, Miesje, Rianna, Carmela, van Stalborch, Anne-Marieke, de Ligt, Aafke, Hoogenboezem, Mark, Tol, Simon, van Rijssel, Jos, Szulcek, Robert, Bogaard, Harm Jan, Hofmann, Patrick, Boon, Reinier, Radmacher, Manfred, de Waard, Vivian, Huveneers, Stephan, van Buul, Jaap D.
• Format: Article
• Language: English
• Subjects: Cells, Cultured; diapedesis; DLC-1; endothelial; GTPase-Activating Proteins - genetics; GTPase-Activating Proteins - metabolism; Human Umbilical Vein Endothelial Cells - metabolism; Human Umbilical Vein Endothelial Cells - physiology; Humans; ICAM-1; Intercellular Adhesion Molecule-1 - metabolism; leukocyte; Leukocytes - metabolism; Leukocytes - physiology; mechanosignaling; Microfilament Proteins - metabolism; rolling; spreading; stiffness; Transendothelial and Transepithelial Migration; transmigration; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Vascular Stiffness
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2018.08.045

Leukocytes follow the well-defined steps of rolling, spreading, and crawling prior to diapedesis through endothelial cells (ECs). We found increased expression of DLC-1 in stiffness-associated diseases like atherosclerosis and pulmonary arterial hypertension. Depletion of DLC-1 in ECs cultured on stiff substrates drastically reduced cell stiffness and mimicked leukocyte transmigration kinetics observed for ECs cultured on soft substrates. Mechanistic studies revealed that DLC-1-depleted ECs or ECs cultured on soft substrates failed to recruit the actin-adaptor proteins filamin B, α-actinin-4, and cortactin to clustered ICAM-1, thereby preventing the ICAM-1 adhesome formation and impairing leukocyte spreading. This was rescued by overexpressing DLC-1, resulting in ICAM-1 adhesome stabilization and leukocyte spreading. Our results reveal an essential role for substrate stiffness-regulated endothelial DLC-1, independent of its GAP domain, in locally stabilizing the ICAM-1 adhesome to promote leukocyte spreading, essential for efficient leukocyte transendothelial migration. [Display omitted] •DLC-1 expression is stiffness related and determines local stiffness•The RhoGAP DLC-1 is crucial for the ICAM-1 adhesome•DLC-1 shows increased expression in stiffness-related diseases•DLC-1 regulates leukocyte spreading independent of its GAP domain Leukocyte extravasation depends on local cellular and substrate stiffness. Schimmel et al. identified endothelial DLC-1 as a mediator to translate stiffness to leukocyte behavior. DLC-1 is crucial for the ICAM-1 adhesome, which allows leukocytes to switch from the rolling to the spreading and crawling phase, followed by diapedesis.