Endocytosis of tight junctions caveolin nitrosylation dependent is improved by cocoa via opioid receptor on RPE cells in diabetic conditions
| Autor: | Mariana Aparecida Brunini Rosales, Diego Andreazzi Duarte, Franco Aparecido Rossato, José B. Lopes de Faria, Jacqueline M. Lopes de Faria, Kamila C. Silva |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
medicine.medical_specialty
Swine Nitrosation Blotting Western Caveolin 1 Blood–retinal barrier Nitric Oxide Synthase Type II Retinal Pigment Epithelium Biology Endocytosis Occludin Permeability Nitric oxide Cell Line Tight Junctions chemistry.chemical_compound Internal medicine Caveolin Blood-Retinal Barrier Claudin-1 medicine Electric Impedance Animals Humans Fluorescent Antibody Technique Indirect Cacao Tight junction Tumor Necrosis Factor-alpha Nitrosylation food and beverages Polyphenols Dextrans Cell biology Nitric oxide synthase medicine.anatomical_structure Endocrinology Glucose chemistry Receptors Opioid biology.protein Reactive Oxygen Species |
| Zdroj: | Investigative ophthalmologyvisual science. 55(9) |
| ISSN: | 1552-5783 |
| Popis: | PURPOSE Retinal pigment epithelium cells, along with tight junction (TJ) proteins, constitute the outer blood retinal barrier (BRB). Contradictory findings suggest a role for the outer BRB in the pathogenesis of diabetic retinopathy (DR). The aim of this study was to investigate whether the mechanisms involved in these alterations are sensitive to nitrosative stress, and if cocoa or epicatechin (EC) protects from this damage under diabetic (DM) milieu conditions. METHODS Cells of a human RPE line (ARPE-19) were exposed to high-glucose (HG) conditions for 24 hours in the presence or absence of cocoa powder containing 0.5% or 60.5% polyphenol (low-polyphenol cocoa [LPC] and high-polyphenol cocoa [HPC], respectively). RESULTS Exposure to HG decreased claudin-1 and occludin TJ expressions and increased extracellular matrix accumulation (ECM), whereas levels of TNF-α and inducible nitric oxide synthase (iNOS) were upregulated, accompanied by increased nitric oxide levels. This nitrosative stress resulted in S-nitrosylation of caveolin-1 (CAV-1), which in turn increased CAV-1 traffic and its interactions with claudin-1 and occludin. This cascade was inhibited by treatment with HPC or EC through δ-opioid receptor (DOR) binding and stimulation, thereby decreasing TNF-α-induced iNOS upregulation and CAV-1 endocytosis. The TJ functions were restored, leading to prevention of paracellular permeability, restoration of resistance of the ARPE-19 monolayer, and decreased ECM accumulation. CONCLUSIONS The detrimental effects on TJs in ARPE-19 cells exposed to DM milieu occur through a CAV-1 S-nitrosylation-dependent endocytosis mechanism. High-polyphenol cocoa or EC exerts protective effects through DOR stimulation. |
| Databáze: | OpenAIRE |
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