title: Transcription and translation of human F11R gene are required for an initial step of atherogenesis induced by inflammatory cytokines.
abstract: BACKGROUND
  The F11 Receptor (F11R; aka JAM-A, JAM-1) is a cell adhesion protein present constitutively on the membrane surface of circulating platelets and within tight junctions of endothelial cells (ECs). Previous reports demonstrated that exposure of ECs to pro-inflammatory cytokines causes insertion of F11R molecules into the luminal surface of ECs, ensuing with homologous interactions between F11R molecules of platelets and ECs, and a resultant adhesion of platelets to the inflamed ECs. The main new finding of the present report is that the first step in this chain of events is the de-novo transcription and translation of F11R molecules, induced in ECs by exposure to inflammatory cytokines.
  
  
  METHODS
  The experimental approach utilized isolated, washed human platelet suspensions and cultured human venous endothelial cells (HUVEC) and human arterial endothelial cells (HAEC) exposed to the proinflammatory cytokines TNF-alpha and/or IFN-gamma, for examination of the ability of human platelets to adhere to the inflamed ECs thru the F11R. Our strategy was based on testing the effects of the following inhibitors on this activity: general mRNA synthesis inhibitors, inhibitors of the NF-kappaB and JAK/STAT pathways, and small interfering F11R-mRNA (siRNAs) to specifically silence the F11R gene.
  
  
  RESULTS
  Treatment of inflamed ECs with the inhibitors actinomycin, parthenolide or with AG-480 resulted in complete blockade of F11R- mRNA expression, indicating the involvement of NF-kappaB and JAK/STAT pathways in this induction. Transfection of ECs with F11R siRNAs caused complete inhibition of the cytokine-induced upregulation of F11R mRNA and inhibition of detection of the newly- translated F11R molecules in cytokine-inflamed ECs. The functional consequence of the inhibition of F11R transcription and translation was the significant blockade of the adhesion of human platelets to inflamed ECs.
  
  
  CONCLUSIONS
  These results prove that de novo synthesis of F11R in ECs is required for the adhesion of platelets to inflamed ECs. Because platelet adhesion to an inflamed endothelium is crucial for plaque formation in non-denuded blood vessels, we conclude that the de-novo translation of F11R is a crucial early step in the initiation of atherogenesis, leading to atherosclerosis, heart attacks and stroke.
authors.affiliation: Division of Cardiology, Department of Medicine, State University of New York, Downstate Medical Center, Brooklyn, New York 11203, USA.
authors.forename: Bani M
authors.initials: BM
authors.lastname: Azari
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Marmur
authors.forename: Moro O
authors.initials: MO
authors.lastname: Salifu
authors.forename: Yigal H
authors.initials: YH
authors.lastname: Ehrlich
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kornecki
authors.forename: Anna
authors.initials: A
authors.lastname: Babinska
mesh_terms: D001011:Aorta / Q000473:pathology; D050197:Atherosclerosis / Q000235:genetics* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D016207:Cytokines / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000473:pathology; D018836:Inflammation Mediators / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology; D010973:Platelet Adhesiveness / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000473:pathology
chemical_list: D015815:Cell Adhesion Molecules; D016207:Cytokines; C407243:F11R protein, human; D018836:Inflammation Mediators; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma