Atherogenic mononuclear cell recruitment is facilitated by oxidized lipoprotein-induced endothelial junctional adhesion molecule-A redistribution

• Published in: Atherosclerosis Vol. 234; no. 2; pp. 254 - 264
• Main Authors: Schmitt, Martin M.N, Fraemohs, Line, Hackeng, Tilman M, Weber, Christian, Koenen, Rory R
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01-06-2014
• Subjects: Animals; Anti-Inflammatory Agents - pharmacology; Apolipoproteins E - deficiency; Apolipoproteins E - genetics; Atherosclerosis; Atherosclerosis - genetics; Atherosclerosis - metabolism; Atherosclerosis - pathology; Cardiovascular; Cell Adhesion Molecules - deficiency; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - metabolism; Cells, Cultured; Coculture Techniques; Endothelial cells; Endothelial Cells - drug effects; Endothelial Cells - metabolism; F11R; Humans; Inflammation - genetics; Inflammation - metabolism; Inflammation - pathology; Inflammation Mediators - metabolism; JAM-1; Junctional adhesion molecule; Leukocyte Rolling; Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - metabolism; Lipoproteins, LDL - metabolism; Lovastatin - pharmacology; Mice; Mice, Knockout; Permeability; Protein Transport; Receptors, Cell Surface - deficiency; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; RNA Interference; Signal Transduction; Statin; Thiazolidinediones - pharmacology; Transendothelial and Transepithelial Migration - drug effects; Transfection; Transmigration; Junctional adhesion molecule; Transmigration; Atherosclerosis; JAM-1; Statin; F11R; Endothelial cells
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2014.03.014

Abstract Background Junctional adhesion molecule (JAM-) A is a transmembrane protein expressed in many cell types and maintains junctional integrity in endothelial cells. Upon inflammatory stimulation, JAM-A relocates to the apical surface and might thereby facilitate the recruitment of leukocytes. Objective Although inflammatory JAM-A redistribution is an established process, further effort is required to understand its exact role in the transmigration of mononuclear cells, particularly under atherogenic conditions. Methods By the use of RNA interference and genetic deletion, the role of JAM-A in the transmigration of T cells and monocytes through aortic endothelial cells was investigated. JAM-A–localization and subsequent mononuclear cell rolling, adhesion and transmigration were explored during endothelial inflammation, induced by oxidized LDL or cytokines. Results RNA interference or genetic deletion of JAM-A in aortic endothelial cells resulted in a decreased transmigration of mononuclear cells. Treatment of the endothelial cells with oxLDL resulted in an increase of both permeability and apical JAM-A presentation, as shown by bead adhesion and confocal microscopy experiments. Redistribution of JAM-A resulted in an increased leukocyte adhesion and transmigration, which could be inhibited with antibodies against JAM-A or by lovastatin-treatment, but not with the peroxisome proliferator activated receptor gamma-agonist pioglitazone. Conclusions This study demonstrates that redistribution of JAM-A in endothelial cells after stimulation with pro-atherogenic oxidized lipoproteins results in increased transmigration of mononuclear cells. This inflammatory dispersal of JAM-A could be counteracted with statins, revealing a novel aspect of their mechanism of action.