| First Author | Pluskota E | Year | 2017 |
| Journal | J Physiol | Volume | 595 |
| Issue | 20 | Pages | 6443-6462 |
| PubMed ID | 28799653 | Mgi Jnum | J:296110 |
| Mgi Id | MGI:6467695 | Doi | 10.1113/JP274380 |
| Citation | Pluskota E, et al. (2017) Kindlin-2 interacts with endothelial adherens junctions to support vascular barrier integrity. J Physiol 595(20):6443-6462 |
| abstractText | KEY POINTS: A reduction in Kindlin-2 levels in endothelial cells compromises vascular barrier function. Kindlin-2 is a previously unrecognized component of endothelial adherens junctions. By interacting directly and simultaneously with beta- or gamma-catenin and cortical actin filaments, Kindlin-2 stabilizes adherens junctions. The Kindlin-2 binding sites for beta- and gamma-catenin reside within its F1 and F3 subdomains. Although Kindlin-2 does not associate directly with tight junctions, its downregulation also destabilizes these junctions. Thus, impairment of both adherens and tight junctions may contribute to enhanced leakiness of vasculature in Kindlin-2(+/-) mice. ABSTRACT: Endothelial cells (EC) establish a physical barrier between the blood and surrounding tissue. Impairment of this barrier can occur during inflammation, ischaemia or sepsis and cause severe organ dysfunction. Kindlin-2, which is primarily recognized as a focal adhesion protein in EC, was not anticipated to have a role in vascular barrier. We tested the role of Kindlin-2 in regulating vascular integrity using several different approaches to decrease Kindlin-2 levels in EC. Reduced levels of Kindlin-2 in Kindlin-2(+/-) mice aortic endothelial cells (MAECs) from these mice, and human umbilical ECs (HUVEC) treated with Kindlin-2 siRNA showed enhanced basal and platelet-activating factor (PAF) or lipopolysaccharide-stimulated vascular leakage compared to wild-type (WT) counterparts. PAF preferentially disrupted the Kindlin-2(+/-) MAECs barrier to BSA and dextran and reduced transendothelial resistance compared to WT cells. Kindlin-2 co-localized and co-immunoprecipitated with vascular endothelial cadherin-based complexes, including beta- and gamma-catenin and actin, components of adherens junctions (AJ). Direct interaction of Kindlin-2 with beta- and gamma-catenin and actin was demonstrated in co-immunoprecipitation and surface plasmon resonance experiments. In thrombin-stimulated HUVECs, Kindlin-2 and cortical actin dissociated from stable AJs and redistributed to radial actin stress fibres of remodelling focal AJs. The beta- and gamma-catenin binding site resides within the F1 and F3 subdomains of Kindlin-2 but not the integrin binding site in F3. These results establish a previously unrecognized and vital role of Kindlin-2 with respect to maintaining the vascular barrier by linking Vascuar endothelial cadherin-based complexes to cortical actin and thereby stabilizing AJ. |
