Partial characterization of the human retinal endothelial cell tight and adherens junction complexes.

Russ PK, Davidson MK, Hoffman LH, Haselton FR
Invest Ophthalmol Vis Sci. 1998 39 (12): 2479-85

PMID: 9804158

PURPOSE - In diabetic retinopathy and macular edema, the blood-retinal barrier fails to function properly, and there is transvascular leakage of proteins and solutes. The tight junction protein occludin and the adherens junction protein cadherin-5 have been shown to be critical to maintaining the endothelial barrier and regulating paracellular transport of large vessel endothelia. However, the expression and distribution of these junction proteins in the retinal endothelium is not well characterized.

METHODS - Human and bovine retinal endothelial cells were isolated as described previously. Western blot analysis and flow cytometry techniques were used to assay for the presence of occludin, zonula occludens-1 (ZO-1), cadherin-5, and beta-catenin. The subcellular localization of the proteins was visualized by immunohistochemistry performed on cultured human retinal endothelial cells and cryosections of bovine retina.

RESULTS - Western blot analysis and flow cytometry techniques found occludin, ZO-1, cadherin-5, and beta-catenin in cultured human retinal endothelial cells. Immunofluorescence staining of cultured retinal endothelial cells and cryosections of bovine retina showed junctional localization of occludin, ZO-1, cadherin-5, and beta-catenin.

CONCLUSIONS - This report demonstrates the expression of occludin and cadherin-5 in retinal endothelial cells and their localization to sites of cell-cell contact. Expression of their respective regulatory proteins, ZO-1 and beta-catenin, at sites of cell-cell contact suggests that occludin and cadherin-5 play a role in maintaining the retinal endothelial barrier.

MeSH Terms (21)

Animals Antibodies, Monoclonal Antigens, CD beta Catenin Blood-Retinal Barrier Blotting, Western Cadherins Cattle Cell Communication Cytoskeletal Proteins Endothelium, Vascular Flow Cytometry Fluorescent Antibody Technique, Indirect Humans Membrane Proteins Occludin Phosphoproteins Retinal Vessels Tight Junctions Trans-Activators Zonula Occludens-1 Protein

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