title: Tight junction peptide antagonists enhance neutrophil trans-endothelial chemotaxis.
abstract: Occludin is an integral membrane protein within tight junctions. Previous studies suggest it functions as a sealing element, which promotes barrier in endothelial and epithelial cell layers. Here, we examine the role of occludin in neutrophil chemotaxis, using cyclic occludin peptide antagonists that incorporate a conserved occludin cell adhesion recognition (CAR) sequence. Human umbilical vein endothelial cells were pre-treated with occludin specific cyclic peptide antagonists to examine effects on neutrophil migration towards a chemotactic gradient of 10(-7) M fMLP. The spatial organization of occludin and VE-cadherin were also assessed in control and occludin peptide-treated monolayers by immunofluorescent staining. The cyclic peptide, peptide B, which contains the CAR sequence of occludin, increased neutrophil chemotaxis in a time and dose dependent manner. Scrambled sequence peptide controls and linear peptides did not. The cyclic occludin antagonist, peptide B, disorganized junctional occludin, but apparently not VE-cadherin as assessed by immunofluorescence. The correlation between diminished occludin organization and increased neutrophil trans-endothelial chemotaxis provides additional support for occludin in the maintenance of the tight junctional barrier.
authors.affiliation: Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport 71130-3932, USA.
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Oshima
authors.forename: Orest
authors.initials: O
authors.lastname: Blaschuk
authors.forename: Barbara
authors.initials: B
authors.lastname: Gour
authors.forename: Matt
authors.initials: M
authors.lastname: Symonds
authors.forename: John W
authors.initials: JW
authors.lastname: Elrod
authors.forename: Makotoh
authors.initials: M
authors.lastname: Sasaki
authors.forename: T Haller
authors.initials: TH
authors.lastname: Jackson
authors.forename: J Steven
authors.initials: JS
authors.lastname: Alexander
mesh_terms: D000328:Adult; D015820:Cadherins / Q000378:metabolism; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects*; D004745:Enkephalins / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007231:Infant, Newborn; D008565:Membrane Proteins / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects*; D062793:Occludin; D011498:Protein Precursors / Q000494:pharmacology*; D019108:Tight Junctions / Q000187:drug effects*; D013997:Time Factors
chemical_list: D015820:Cadherins; D004745:Enkephalins; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D011498:Protein Precursors; C056943:peptide B; D009240:N-Formylmethionine Leucyl-Phenylalanine; C042932:formylmethionyl-leucyl-phenylalanine methyl ester