Premium
Occludin is essential for tumor necrosis factor (TNF)‐induced intestinal epithelial tight junction (TJ) disruption
Author(s) -
Shen Le,
Weber Christopher R.,
Wu Licheng,
Wang Yingmin,
Turner Jerrold R.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1066.4
Subject(s) - occludin , tumor necrosis factor alpha , tight junction , tumor necrosis factor α , microbiology and biotechnology , cancer research , chemistry , medicine , immunology , biology
TNF decreases intestinal epithelial TJ barrier function by a myosin light chain kinase‐ (MLCK‐) dependent process. Although endocytosis of occludin following TNF‐induced MLCK activation is required for barrier loss, specific contributions of occludin are poorly defined. Our aim was to define the role of occludin domains in TNF‐induced TJ disruption. Stable occludin knockdown (KD) decreased transepithelial resistance (TER) of Caco‐2 monolayers to 59 ± 7 % of wild type (WT). Analysis of cation and FITC‐dextran flux showed that this was primarily due to increased permeability to large solutes; 3kDa FITC‐dextran flux was 474 ± 52 % of control. Expression and trafficking of other TJ proteins were unaffected by occludin KD. TNF decreased TER of IFNγ‐primed WT monolayers by 14 ± 1 % after 4 hrs, but TER of occludin KD monolayers was unchanged, despite increased MLC phosphorylation. Stable reexpression of WT occludin, but not a mutant lacking the C‐terminal coiled‐coil domain, resensitized occludin KD monolayers to TNF‐induced barrier loss. This was not due to defective trafficking, as the occludin deletion mutant was efficiently delivered to the TJ. Thus, occludin contributes to TNF‐induced TJ barrier loss by a mechanism that involves the C‐terminal coiled‐coil domain. This suggests that protein interactions mediated by the coiled‐coil domain are required for TNF‐induced barrier loss. Supported by NIH and CCFA.