S-Layer Protein of Lactobacillus helveticus SBT2171 Promotes Human β-Defensin 2 Expression via TLR2–JNK Signaling

Abstract

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 (LAB) 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.

Yogurt Produced by Novel Natural Starter Cultures Improves Gut Epithelial Barrier In Vitro

“…Importantly, the results showed increased DEFB1 mRNA levels after yogurt treatment, compared to control ( Figure 3 D). Similar results were reported for Lactobacillus helveticus SBT2171 (LH2171) strain, which induced the expression of human β-defensin in Caco-2 cells by activating c-Jun N-terminal kinase (JNK) signaling via Toll-like receptor TLR2 [ 92 ].…”

Antilisterial Potential of Lactic Acid Bacteria in Eliminating Listeria monocytogenes in Host and Ready-to-Eat Food Application

“…L. helveticus membrane protein was reported to have a greater extent in human beta-densin-2 (hBD2) expression compared with cells. The membrane protein as TLR2 antagonist activates TLR2 downstream signaling, including MAPK, NF-κB, and mainly c-Jun N-terminal kinase signaling, mediating the upregulation of hBD2 as suggested [119]. However, the exact role of NOD in AMPs' expression is poorly known because there are conflicting reports, suggesting the possibility of an additional function of NOD in Paneth cells beyond regulation of AMPs' secretion and activity [43,48,90,115,117,120].…”

Biogenic action of Lactobacillus plantarum SBT2227 promotes sleep in Drosophila melanogaster

“…For example, biogenic actions of bacterial substrates have been shown to reduce body fat in humans ( Nakamura et al., 2016 ) and, in rodents, to prevent cancer ( Badr El-Din et al., 2020 ; Zhang et al., 2013 ), hypertension ( Chanson-Rolle et al., 2015 ; Cheng and Pan, 2017 ) and inflammation ( Yang et al., 2015 , 2017 ). Furthermore, in vitro model systems have suggested that lipid metabolism ( Monagas et al., 2010 ) and the immune system ( Kobatake and Kabuki, 2019 ) are modulated by bacterial substrates. Compared to probiotics and prebiotics, knowledge regarding the effects of biogenics on higher-brain functions is limited.…”