title: GILZ overexpression inhibits endothelial cell adhesive function through regulation of NF-κB and MAPK activity.
abstract: Glucocorticoid-induced leucine zipper (GILZ) is an anti-inflammatory protein first identified in T lymphocytes. We recently observed that GILZ is highly expressed in synovial endothelial cells in rheumatoid arthritis. However, the function of GILZ in endothelial cells is unknown. To investigate the actions of GILZ in this cell type, we induced GILZ expression in HUVECs via transient transfection. GILZ overexpression significantly reduced the capacity of TNF-stimulated HUVECs to support leukocyte rolling, adhesion, and transmigration. These effects were associated with decreased expression of E-selectin, ICAM-1, CCL2, CXCL8, and IL-6. Experiments in a human microvascular endothelial cell line demonstrated that TNF-inducible NF-κB activity was significantly inhibited by overexpression of GILZ. Exogenous GILZ inhibited TNF-induced NF-κB p65 DNA binding, although this occurred in the absence of an effect on p65 nuclear translocation, indicating that the mechanism of action of exogenous GILZ in endothelial cells differs from that reported in other cell types. GILZ overexpression also inhibited TNF-induced activation of p38, ERK, and JNK MAPKs, as well as increased expression of the MAPK inhibitory phosphatase, MKP-1. In contrast, silencing endogenous GILZ in glucocorticoid-treated HUVECs did not alter their capacity to support leukocyte interactions. These data demonstrate that exogenous GILZ exerts inhibitory effects on endothelial cell adhesive function via a novel pathway involving modulation of NF-κB p65 DNA binding and MAPK activity. Induction of GILZ expression in endothelial cells may represent a novel therapeutic modality with the potential to inhibit inflammatory leukocyte recruitment.
authors.affiliation: Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, Victoria 3168, Australia.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cheng
authors.forename: Huapeng
authors.initials: H
authors.lastname: Fan
authors.forename: Devi
authors.initials: D
authors.lastname: Ngo
authors.forename: Elaine
authors.initials: E
authors.lastname: Beaulieu
authors.forename: Patrick
authors.initials: P
authors.lastname: Leung
authors.forename: Camden Y
authors.initials: CY
authors.lastname: Lo
authors.forename: Rosemary
authors.initials: R
authors.lastname: Burgess
authors.forename: Yvonne G
authors.initials: YG
authors.lastname: van der Zwan
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: White
authors.forename: Levon M
authors.initials: LM
authors.lastname: Khachigian
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hickey
authors.forename: Eric F
authors.initials: EF
authors.lastname: Morand
mesh_terms: D002448:Cell Adhesion / Q000235:genetics / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D002460:Cell Line; D002464:Cell Migration Inhibition / Q000235:genetics / Q000276:immunology; D004730:Endothelium, Vascular / Q000276:immunology* / Q000378:metabolism* / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007962:Leukocytes / Q000276:immunology / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics / Q000276:immunology*; D008833:Microcirculation / Q000235:genetics / Q000276:immunology; D061251:Primary Cell Culture; D011897:Random Allocation; D051996:Transcription Factor RelA / Q000378:metabolism*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D057705:Transendothelial and Transepithelial Migration / Q000235:genetics / Q000276:immunology*
chemical_list: C404226:TSC22D3 protein, human; D051996:Transcription Factor RelA; D014157:Transcription Factors