title: IL-8-mediated angiogenic responses of endothelial cells to lipid antigen activation of iNKT cells depend on EGFR transactivation.
abstract: iNKT cells are a unique T cell subset, which is CD1d-restricted and specific for glycolipid antigens. In advanced atherosclerotic plaques, focal collections of inflammatory cells correlate with areas of intraplaque neovascularization. We reported recently that iNKT cells might facilitate intraplaque neovascularization by enhancing EC migration and sprouting in an IL-8-dependent manner. This study investigated the participating effector mechanisms. In ECs, CM, derived from antigen-stimulated human iNKT cells (CM+), induced up-regulation of IL-8R CXCR2 and the phosphorylation of EGFR and of multiple intracellular signaling effectors, including FAK, Src, Erk, Jnk, p38-MAPK, and STAT1 and -3. We found that a cascade of events, which were IL-8-dependent and involved EGFR activation, was responsible for signaling through FAK and Src kinases and necessary for acquisition of angiogenic morphology, migration in a two-dimensional wound assay, and sprout outgrowth in a three-dimensional model of angiogenesis in vitro. The data support that IL-8-dependent activation of angiogenic behavior in ECs, in response to activated iNKT, involves CXCR2, transactivation of EGFR, and subsequent FAK/Src signaling. We found too that activated iNKT increased VEGFR2 expression in ECs. Functional studies confirmed that EGF is the motogenic-enhancing factor in CM+ and is necessary, together with an exogenous source of VEGF, for iNKT-promoted sprout formation. EGFR inhibition may represent a novel therapeutic modality aimed at plaque stabilization through control of neovascularization within developing atherosclerotic plaques.
authors.affiliation: Department of Biomedicine, Basel University Hospital, Basel, Switzerland.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Kyriakakis
authors.forename: Marco
authors.initials: M
authors.lastname: Cavallari
authors.forename: Dennis
authors.initials: D
authors.lastname: Pfaff
authors.forename: Doriano
authors.initials: D
authors.lastname: Fabbro
authors.forename: Juergen
authors.initials: J
authors.lastname: Mestan
authors.forename: Maria
authors.initials: M
authors.lastname: Philippova
authors.forename: Gennaro
authors.initials: G
authors.lastname: De Libero
authors.forename: Paul
authors.initials: P
authors.lastname: Erne
authors.forename: Therese J
authors.initials: TJ
authors.lastname: Resink
mesh_terms: D000941:Antigens / Q000276:immunology; D050197:Atherosclerosis / Q000276:immunology / Q000473:pathology; D002450:Cell Communication; D002460:Cell Line; D002465:Cell Movement; D042783:Endothelial Cells / Q000276:immunology* / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007249:Inflammation; D016209:Interleukin-8 / Q000276:immunology* / Q000378:metabolism; D008055:Lipids / Q000276:immunology; D008213:Lymphocyte Activation / Q000502:physiology*; D055611:Natural Killer T-Cells / Q000276:immunology* / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation; D023063:Receptors, Interleukin-8B / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D015854:Up-Regulation
chemical_list: D000941:Antigens; D016209:Interleukin-8; D008055:Lipids; D023063:Receptors, Interleukin-8B; D004815:Epidermal Growth Factor; D066246:ErbB Receptors