title: Kruppel-like factor 4 regulates endothelial inflammation.
abstract: The vascular endothelium plays a critical role in vascular homeostasis. Inflammatory cytokines and non-laminar blood flow induce endothelial dysfunction and confer a pro-adhesive and pro-thrombotic phenotype. Therefore, identification of factors that mediate the effects of these stimuli on endothelial function is of considerable interest. Kruppel-like factor 4 expression has been documented in endothelial cells, but a function has not been described. In this communication we describe the expression in vitro and in vivo of Kruppel-like factor 4 in human and mouse endothelial cells. Furthermore, we demonstrate that endothelial Kruppel-like factor 4 is induced by pro-inflammatory stimuli and shear stress. Overexpression of Kruppel-like factor 4 induces expression of multiple anti-inflammatory and anti-thrombotic factors including endothelial nitric-oxide synthase and thrombomodulin, whereas knockdown of Kruppellike factor 4 leads to enhancement of tumor necrosis factor alpha-induced vascular cell adhesion molecule-1 and tissue factor expression. The functional importance of Kruppel-like factor 4 is verified by demonstrating that Kruppel-like factor 4 expression markedly decreases inflammatory cell adhesion to the endothelial surface and prolongs clotting time under inflammatory states. Kruppel-like factor 4 differentially regulates the promoter activity of pro- and anti-inflammatory genes in a manner consistent with its anti-inflammatory function. These data implicate Kruppel-like factor 4 as a novel regulator of endothelial activation in response to pro-inflammatory stimuli.
authors.affiliation: Cardiovascular Research Institute, Case Western Reserve University, Cleveland, Ohio 44106-7290, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Hamik
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Lin
authors.forename: Ajay
authors.initials: A
authors.lastname: Kumar
authors.forename: Mercedes
authors.initials: M
authors.lastname: Balcells
authors.forename: Sumita
authors.initials: S
authors.lastname: Sinha
authors.forename: Jonathan
authors.initials: J
authors.lastname: Katz
authors.forename: Mark W
authors.initials: MW
authors.lastname: Feinberg
authors.forename: Robert E
authors.initials: RE
authors.lastname: Gerzsten
authors.forename: Elazer R
authors.initials: ER
authors.lastname: Edelman
authors.forename: Mukesh K
authors.initials: MK
authors.lastname: Jain
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000235:genetics; D002448:Cell Adhesion / Q000235:genetics; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000172:deficiency / Q000378:metabolism*; D051379:Mice; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis; D013314:Stress, Mechanical; D018180:Thrombomodulin / Q000096:biosynthesis; D013927:Thrombosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D014657:Vasculitis / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D018836:Inflammation Mediators; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D018180:Thrombomodulin; C496314:NOS3 protein, human; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse