title: Endothelial connexin 32 regulates tissue factor expression induced by inflammatory stimulation and direct cell-cell interaction with activated cells.
abstract: OBJECTIVE
  Endothelial cell (EC) interacts with adjacent EC through gap junction, and abnormal expression or function of Cxs is associated with cardiovascular diseases. In patients with endothelial dysfunction, the up-regulation of tissue factor (TF) expression promotes the pathogenic activation of blood coagulation, however the relationship between gap junctions and TF expression in ECs remains uncharacterized. ECs express the gap junction (GJ) proteins connexin32 (Cx32), Cx37, Cx40 and Cx43. We investigated the role of endothelial gap junctions, particularly Cx32, in modulating TF expression during vascular inflammation.
  
  
  RESULTS
  Human umbilical vein endothelial cells (HUVECs) were stimulated with tumor necrosis factor-α (TNF-α) and TF activity was assessed in the presence of GJ blockers and an inhibitory anti-Cx32 monoclonal antibody. Treatment with GJ blockers and anti-Cx32 monoclonal antibody enhanced the TNF-α-induced TF activity and mRNA expression in HUVECs. TNF-α-activated effector HUVECs or mouse MS-1 cells were co-cultured with non-stimulated acceptor HUVECs and TF expression in acceptor HUVECs was detected. Effector EC induced TF expression in adjacent acceptor HUVECs through direct cell-cell interaction. Cell-cell interaction induced TF expression was reduced by anti-intercellular adhesion molecule-1 (ICAM1) monoclonal antibody. Soluble ICAM1-Fc fusion protein promotes TF expression. GJ blockers and anti-Cx32 monoclonal antibody enhanced TF expression induced by cell-cell interaction and ICAM1-Fc treatment.
  
  
  CONCLUSIONS
  Blockade of endothelial Cx32 increased TF expression induced by TNF-α stimulation and cell-cell interaction which was at least partly dependent upon ICAM1. These results suggest that direct Cx32-mediated interaction modulates TF expression in ECs during vascular inflammation.
authors.affiliation: Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Faculty of Medical Engineering, Suzuka University of Medical Science, 1001-1, Kishioka-cho, Suzuka, Mie 510-0293, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Akita
authors.affiliation: Department of Biochemistry, Mie Prefectural College of Nursing, 1-1-1 Yumegaoka, Tsu, Mie 514-0116, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
authors.forename: Motomu
authors.initials: M
authors.lastname: Shimaoka
authors.affiliation: Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan; Faculty of Pharmaceutical Science, Suzuka University of Medical Science, 3500-3, Minamitamagaki-cho, Suzuka, Mie 513-8679, Japan. Electronic address: suzukiko@suzuka-u.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001777:Blood Coagulation; D002229:Carbenoxolone / Q000494:pharmacology; D002450:Cell Communication; D002478:Cells, Cultured; D018920:Coculture Techniques; D017630:Connexins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000502:physiology*; D042783:Endothelial Cells / Q000378:metabolism*; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D018796:Immunoconjugates / Q000494:pharmacology; D007141:Immunoglobulin Fc Fragments; D018799:Intercellular Adhesion Molecule-1 / Q000494:pharmacology / Q000502:physiology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009829:Oleic Acids / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D013925:Thromboplastin / Q000096:biosynthesis* / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014657:Vasculitis / Q000378:metabolism*; D000097002:Gap Junction beta-1 Protein
chemical_list: D000911:Antibodies, Monoclonal; D002229:Carbenoxolone; D017630:Connexins; D018796:Immunoconjugates; D007141:Immunoglobulin Fc Fragments; D018799:Intercellular Adhesion Molecule-1; D009829:Oleic Acids; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D013925:Thromboplastin; D014409:Tumor Necrosis Factor-alpha; D000097002:Gap Junction beta-1 Protein; C029407:oleylamide
keywords: Cell–cell interaction; Connexin; Endothelial cell; Gap junction; Inflammation; Tissue factor