VEGF-induced effects on proliferation, migration and tight junctions are restored by ranibizumab (Lucentis) in microvascular retinal endothelial cells.
BACKGROUND
Because vascular endothelial growth factor (VEGF) signalling is deregulated in diabetic retinopathy, the potential therapeutic effects of VEGF inhibitors such as the human VEGF-specific antibody ranibizumab are currently being tested. A study was undertaken to determine whether VEGF-stimulated processes in retinal endothelial cells are reversed by ranibizumab.


METHODS
The influence of VEGF(121) and VEGF(165) on the proliferation and migration of immortalised bovine retinal endothelial cells (iBREC) was studied in the presence and absence of ranibizumab. In addition, the protein composition of tight junctions in the presence of VEGF and its inhibitor in iBREC was investigated.


RESULTS
While both isoforms stimulated proliferation of iBREC, only VEGF(165) influenced cell migration. The addition of ranibizumab counteracted this stimulation without inhibition of the basal levels of migration and proliferation. Plasma membrane staining of the tight junction proteins occludin and claudin-1 disappeared in the presence of VEGF(165); there was no effect on claudin-5 and ZO-1 was only weakly affected. The addition of ranibizumab restored plasma membrane localisation of occludin and claudin-1. For claudin-1, the variation in total protein expression corresponded with the observed effects of VEGF(165) and ranibizumab.


CONCLUSIONS
Ranibizumab reverses proliferation and cell migration stimulated by VEGF and delocalisation of tight junction proteins induced by VEGF(165) in iBREC.
Department of Ophthalmology, University of Ulm Medical School, Prittwitzstrasse 43, D-89075 Ulm, Germany. heidrun.deissler@uniklinik-ulm.de
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D015153:Blotting, Western / Q000379:methods; D002417:Cattle; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D062445:Claudin-1; D042783:Endothelial Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D008833:Microcirculation; D062793:Occludin; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism; D000069579:Ranibizumab; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D019108:Tight Junctions / Q000737:chemistry / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D062826:Zonula Occludens-1 Protein
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C568108:CLDN1 protein, human; D062445:Claudin-1; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; C569042:TJP1 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D062826:Zonula Occludens-1 Protein; D000069579:Ranibizumab