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Green tea extract and its major constituent, epigallocatechin‐3‐gallate, induce epithelial beta‐defensin secretion and prevent beta‐defensin degradation by P orphyromonas gingivalis
Author(s) -
Lombardo Bedran T. B.,
Feghali K.,
Zhao L.,
Palomari Spolidorio D. M.,
Grenier D.
Publication year - 2014
Publication title -
journal of periodontal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.31
H-Index - 83
eISSN - 1600-0765
pISSN - 0022-3484
DOI - 10.1111/jre.12142
Subject(s) - beta defensin , secretion , defensin , epigallocatechin gallate , proteases , antimicrobial peptides , green tea extract , microbiology and biotechnology , chemistry , biology , pharmacology , biochemistry , antimicrobial , polyphenol , enzyme , green tea , antioxidant , food science
Background and Objective Antimicrobial peptides, such as beta‐defensins, secreted by gingival epithelial cells, are thought to play a major role in preventing periodontal diseases. In the present study, we investigated the ability of green tea polyphenols to induce human beta‐defensin (h BD ) secretion in gingival epithelial cells and to protect h BD s from proteolytic degradation by P orphyromonas gingivalis . Material and Methods Gingival epithelial cells were treated with various amounts (25–200 μg/ mL ) of green tea extract or epigallocatechin‐3‐gallate (EGCG). The secretion of h BD 1 and h BD 2 was measured using ELISAs , and gene expression was quantified by real‐time PCR . The treatments were also carried out in the presence of specific kinase inhibitors to identify the signaling pathways involved in hBD secretion. The ability of green tea extract and EGCG to prevent hBD degradation by proteases of P. gingivalis present in a bacterial culture supernatant was evaluated by ELISA . Results The secretion of h BD 1 and h BD 2 was up‐regulated, in a dose‐dependent manner, following the stimulation of gingival epithelial cells with a green tea extract or EGCG . Expression of the hBD gene in gingival epithelial cells treated with green tea polyphenols was also increased. EGCG‐induced secretion of h BD 1 and h BD 2 appeared to involve extracellular signal‐regulated kinase 1/2 and p38 mitogen‐activated protein kinase. Lastly, green tea extract and EGCG prevented the degradation of recombinant h BD 1 and h BD 2 by a culture supernatant of P. gingivalis . Conclusion Green tea extract and EGCG, through their ability to induce h BD secretion by epithelial cells and to protect h BD s from proteolytic degradation by P. gingivalis , have the potential to strengthen the epithelial antimicrobial barrier. Future clinical studies will indicate whether these polyphenols represent a valuable therapeutic agent for treating/preventing periodontal diseases.