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Front. Microbiol. | doi: 10.3389/fmicb.2019.02414

S-layer protein of Lactobacillus helveticus SBT2171 promotes human β-defensin 2 expression via TLR2–JNK signaling

  • 1Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Japan

Antimicrobial peptides that contribute to innate immunity are among the most important protective measures against infection in many organisms. Several substances are known to regulate the expression of antimicrobial peptides. In this study, we investigated the factors in lactic acid bacteria that induce antimicrobial peptide expression in the host. We found that Lactobacillus helveticus SBT2171 (LH2171) induced the expression of human β-defensin (hBD)2 in Caco-2 human colonic epithelial cells. Specifically, surface layer protein (SLP) of LH2171 stimulated hBD2 expression by activating c-Jun N-terminal kinase (JNK) signaling via Toll-like receptor (TLR)2 in Caco-2 cells. SLPs extracted from other lactobacilli similarly increased hBD2 expression, suggesting that this stimulatory effect is common feature of Lactobacillus SLPs. Interestingly, Lactobacillus strains that strongly induced hBD2 expression also potently activated JNK signaling. Thus, upregulation of hBD2 induced by TLR2–JNK signaling contributes to protection of the host against infection.

Keywords: Surface-layer protein, Antimicrobial peptide, human beta defensin 2, Lactic acid bacteria, Lactobacilus helveticus SBT2171, C-Jun N-terminal kinase, Toll-like receptoer 2

Received: 17 Jun 2019; Accepted: 07 Oct 2019.

Copyright: © 2019 Kobatake and Kabuki. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mr. Eiji Kobatake, Milk Science Research Institute, Megmilk Snow Brand Co., Ltd., Saitama, Japan, eiji-kobatake@meg-snow.com