title: Knock-down of endothelial connexins impairs angiogenesis.
abstract: Connexins (Cx) are suggested to play important roles in growth and differentiation. Aim of our study was to investigate the role of endothelial Cx in the angiogenic process. Several parameters of angiogenesis were assessed in 18 h Matrigel in vitro angiogenesis assays with human umbilical vein endothelial cells (HUVEC). Prior to culture on Matrigel cells were treated with nicotine or the gap junction inhibitor palmitoleic acid (PA), or siRNA-knock-down of either Cx37, Cx40 or Cx43 was performed. Changes in Cx expression and their effects on gap-junctional communication were investigated using immunofluorescence microscopy, Western blot and Lucifer Yellow dye transfer. Knock-down of each Cx-isoform significantly reduced the amount of specific Cx protein in HUVEC. Cx-knock-down as well as treatment with PA impaired intercellular communication via gap junctions and diminished significantly the number of capillary branches. Knock-down of Cx43 and Cx40 or treatment with PA reduced complexity pattern in the angiogenesis assay. Nicotine significantly reduced expression of Cx43 and Cx37 as well as average length of capillary branches, number of branches and pattern in the Matrigel assay. We can conclude that connexins are involved in angiogenesis, in particular in branch formation. This can partly explain the changes in angiogenesis seen under nicotine treatment.
authors.affiliation: Department of Cardiac Surgery, Heart Centre Leipzig, University of Leipzig, Struempellstr. 39, 04289 Leipzig, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Gärtner
authors.forename: Barbara
authors.initials: B
authors.lastname: Ziegelhöffer
authors.forename: Martin
authors.initials: M
authors.lastname: Kostelka
authors.forename: Holger
authors.initials: H
authors.lastname: Stepan
authors.forename: Friedrich-Wilhelm
authors.initials: FW
authors.lastname: Mohr
authors.forename: Stefan
authors.initials: S
authors.lastname: Dhein
mesh_terms: D002450:Cell Communication / Q000187:drug effects; D017630:Connexins / Q000235:genetics* / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D017629:Gap Junctions / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D017630:Connexins; D005229:Fatty Acids, Monounsaturated; D034741:RNA, Small Interfering; C008757:palmitoleic acid; D009538:Nicotine