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Probiotics Prevent Oxidative Stress‐Induced Disruption of Intestinal Epithelial Barrier Function by EGF Receptor, PKC and MAP Kinase‐Dependent Mechanism
Author(s) -
Rao RK,
Yan F,
Polk D Brent,
Seth A
Publication year - 2007
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.21.5.a585-a
Subject(s) - occludin , barrier function , tight junction , protein kinase c , microbiology and biotechnology , mapk/erk pathway , oxidative stress , chemistry , kinase , biology , biochemistry
Oxidative stress disrupts intestinal epithelial tight junctions (TJ) and plays a crucial role in the pathogenesis of intestinal inflammatory diseases. Probiotics protect the GI mucosa from a variety of insults. In the present study we evaluated the effect of Lactobacillus GG growth medium (LGGs) and two different proteins, P40 and P75, isolated from LGGs on H 2 O 2 ‐induced disruption of TJ and barrier function in Caco‐2 cell monolayers. Barrier function was evaluated by measuring transepithelial electrical resistance (TER) and inulin flux. TJ integrity was analyzed by immunofluorescence microscopy of occludin and ZO‐1, and their distribution in detergent‐insoluble fractions. We evaluated the effect of AG1478 (inhibitor of EGFR Tyr kinase), R0320432 (PKC inhibitor) and U0126 (MAPK inhibitor) to determine the role of EGFR, PKC and MAPK in probiotic‐mediated protection of TJ. Activation of EGFR, PKC isoforms and ERK1/2 by probiotics was determined by immunoblot analysis. LGGs, P40 and P75 dose‐dependently prevented H 2 O 2 ‐induced decrease in TER, increase in inulin flux, redistribution of occludin and ZO‐1 from the junction, and loss of detergent‐insoluble occludin and ZO‐1. AG1478, R0320432 and U0126 attenuated probiotic‐mediated prevention of H 2 O 2 ‐induced disruption of TJ and loss of barrier function. Both P40 and P75 rapidly induced Tyr‐phosphorylation of EGFR, membrane translocation of PKCβI and PKCε, and increased the level of active ERK1/2. These results demonstrate that probiotic secretory proteins protect TJ from H 2 O 2 by EGFR, PKC and MAP kinase‐dependent mechanism.