title: Oxidized LDL signals through Rho-GTPase to induce endothelial cell stiffening and promote capillary formation.
abstract: Endothelial biomechanics is emerging as a key factor in endothelial function. Here, we address the mechanisms of endothelial stiffening induced by oxidized LDL (oxLDL) and investigate the role of oxLDL in lumen formation. We show that oxLDL-induced endothelial stiffening is mediated by CD36-dependent activation of RhoA and its downstream target, Rho kinase (ROCK), via inhibition of myosin light-chain phosphatase (MLCP) and myosin light-chain (MLC)2 phosphorylation. The LC-MS/MS analysis identifies 7-ketocholesterol (7KC) as the major oxysterol in oxLDL. Similarly to oxLDL, 7KC induces RhoA activation, MLCP inhibition, and MLC2 phosphorylation resulting in endothelial stiffening. OxLDL also facilitates formation of endothelial branching networks in 3D collagen gels in vitro and induces increased formation of functional blood vessels in a Matrigel plug assay in vivo. Both effects are RhoA and ROCK dependent. An increase in lumen formation was also observed in response to pre-exposing the cells to 7KC, an oxysterol that induces endothelial stiffening, but not to 5α,6α epoxide that does not affect endothelial stiffness. Importantly, loading cells with cholesterol prevented oxLDL-induced RhoA activation and the downstream signaling cascade, and reversed oxLDL-induced lumen formation. In summary, we show that oxLDL-induced endothelial stiffening is mediated by the CD36/RhoA/ROCK/MLCP/MLC2 pathway and is associated with increased endothelial angiogenic activity.
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Myung-Jin
authors.initials: MJ
authors.lastname: Oh
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Chongxu
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: LeMaster
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Crystal
authors.initials: C
authors.lastname: Adamos
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Berdyshev
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Yedida
authors.initials: Y
authors.lastname: Bogachkov
authors.affiliation: Department of Pharmacology, University of Illinois at Chicago, Chicago, IL.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Kohler
authors.affiliation: Department of Pharmacology, University of Illinois at Chicago, Chicago, IL.
authors.forename: Jugajyoti
authors.initials: J
authors.lastname: Baruah
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL.
authors.forename: Yun
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL.
authors.forename: Dean E
authors.initials: DE
authors.lastname: Schraufnagel
authors.affiliation: Department of Pharmacology, University of Illinois at Chicago, Chicago, IL.
authors.forename: Kishore K
authors.initials: KK
authors.lastname: Wary
authors.affiliation: Division of Pulmonary and Critical Care, Department of Medicine, University of Illinois at Chicago, Chicago, IL levitan@uic.edu.
authors.forename: Irena
authors.initials: I
authors.lastname: Levitan
mesh_terms: D000818:Animals; D024722:Cardiac Myosins / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008077:Lipoproteins, LDL / Q000502:physiology*; D008819:Mice, Nude; D016513:Mice, SCID; D018994:Myosin Light Chains / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D015398:Signal Transduction; D059289:Vascular Stiffness; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D008077:Lipoproteins, LDL; D018994:Myosin Light Chains; C107184:myosin light chain 2; C099252:oxidized low density lipoprotein; C066737:RHOA protein, human; D054460:rho-Associated Kinases; D024722:Cardiac Myosins; D020742:rhoA GTP-Binding Protein
keywords: RhoA; angiogenesis; endothelial stiffness