title: Antibody blockade of junctional adhesion molecule-A in rabbit corneal endothelial tight junctions produces corneal swelling.
abstract: OBJECTIVE
  The ultrastructure of tight junctions in the corneal endothelium has been studied extensively, yet little is known about their molecular composition. Junctional adhesion molecule-A (JAM-A) is a tight junction-associated adhesion protein previously implicated in tight junction assembly and regulation of barrier function. In this study, we sought to investigate the expression and function of JAM-A in the corneal endothelium.
  
  
  METHODS
  Immunofluorescence confocal microscopy was used to investigate expression of JAM-A and the related proteins JAM-C, CAR, and AF-6 in the rabbit corneal endothelium. Corneal endothelial perfusion specular microscopy was then used to test the effects of antibodies to JAM-A on corneal swelling.
  
  
  RESULTS
  The expression of JAM-A was observed in the tight junctions of rabbit corneal endothelium in a localization pattern identical with that of ZO-1, a known marker of the tight junction and binding partner of JAM-A. Expression of related proteins JAM-C and CAR (Coxsackie and adenovirus receptor) was also observed in the corneal endothelium, but their distribution was diffuse and not limited to the tight junction. Expression of AF-6, a known binding partner of JAM-A, was also observed in the tight junction in a pattern similar to ZO-1. Last, functional experiments were performed in which a monoclonal antibody to JAM-A was shown to increase rabbit corneal swelling by 63% compared with the control.
  
  
  CONCLUSIONS
  The results provide new evidence that JAM-A and its binding partner AF-6 are expressed in tight junctions of the corneal endothelium and that JAM-A has a major role in maintaining the corneal endothelial barrier function.
authors.affiliation: Emory Eye Center, Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA. kjmande@emory.edu
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Mandell
authors.forename: Glenn P
authors.initials: GP
authors.lastname: Holley
authors.forename: Charles A
authors.initials: CA
authors.lastname: Parkos
authors.forename: Henry F
authors.initials: HF
authors.lastname: Edelhauser
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000502:physiology; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002463:Cell Membrane Permeability; D015715:Corneal Edema / Q000378:metabolism*; D004728:Endothelium, Corneal / Q000378:metabolism*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D007136:Immunoglobulins / Q000502:physiology*; D016547:Kinesins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D009218:Myosins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011817:Rabbits; D011956:Receptors, Cell Surface; D019108:Tight Junctions / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein
chemical_list: C095516:AFDN protein, human; D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; C407243:F11R protein, human; D007136:Immunoglobulins; D008565:Membrane Proteins; D010750:Phosphoproteins; D011956:Receptors, Cell Surface; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D009218:Myosins; D016547:Kinesins