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Chronic exposure to TNF α impairs RPE barrier and immunosuppressive functions
Author(s) -
Touhami S.,
Beguier F.,
Augustin S.,
Reichman S.,
Goureau O.,
Nandrot E.,
Guillonneau X.,
Bodaghi B.,
Sennlaub F.
Publication year - 2017
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2017.02332
Subject(s) - barrier function , retinal pigment epithelium , tight junction , microbiology and biotechnology , tumor necrosis factor alpha , blood–retinal barrier , inflammation , phagocytosis , biology , cell culture , retinal , andrology , chemistry , immunology , medicine , endocrinology , biochemistry , genetics , diabetic retinopathy , diabetes mellitus
Purpose The retinal pigment epithelium ( RPE ) is a monolayer of pigmented cells with important roles in the outer blood‐retinal barrier and subretinal immune suppression. Failure of RPE functions and inflammation have both been hypothesized to play a role in the pathophysiology of age related macular degeneration ( AMD ). We here investigated the long‐term effects of TNF α on RPE morphology and function in vitro. Methods Primary porcine RPE cells were cultivated until confluence, then recombinant TNF α was added daily in the culture medium (at 0.8, 4, 20 or 100 ng/ml=C1,C2,C3 and C4) for 10 days. RPE cell morphology and gene expression, barrier, phagocytosis and immunosuppressive functions were assessed. Results Cell morphology and gene expression: TNF α (i) decreased cell number (3653.6,3428,3227,2791 and 2020 cells/mm2 respectively for control,C1,C2,C3 and C4, all p < 0.01); (ii) increased cell size (+5.3,+12.6,+13.9 and +9.5% of control for C1,C2,C3 and C4, all p < 0.05); (iii) increased the % of multinucleated cells (5.7,7.7,9.4,9.9 and 15.9% of multinucleated cells for control,C1,C2,C3 and C4, all p < 0.05); (iv) and decreased OTX 2 (a major RPE gene) expression (‐11.1, ‐19.7, ‐52 and ‐82.9% of control for C1,C2,C3 and C4, all p < 0.05). Barrier function: Stimulation by TNF α (i) disturbed Zonula Occludens 1 cellular distribution and actin F distribution and (ii) significantly decreased RPE transepithelial resistance in a dose‐dependent manner (‐70, ‐88.5 and ‐90.8% of control for C2,C3 and C4, p < 0.05). Immunossupressive function: 10 day pre‐stimulation with ‐ TNF α significantly decreased RPE capacity to induce monocyte death after 24 h of co‐culture (p < 0.05). Conclusions Chronic exposure to TNF α deteriorates major RPE functions that are essential to visual function and might play a key role in the pathophysiology of AMD .