Saccharomyces cerevisiae mannan induces sheep beta-defensin-1 expression via Dectin-2-Syk-p38 pathways in ovine ruminal epithelial cells

Abstract

The rumen epithelium of sheep serves as an immune interface with the environment and secretes antimicrobial peptides with bactericidal function against various pathogens. Sheep beta-defensin-1 (SBD-1), an antimicrobial peptide, is secreted from ovine ruminal epithelial cells (OREC) in response to microbial infections. Mannan, the main component of the Saccharomyces cerevisiae cell wall can stimulate innate and regulatory immune responses that could improve the gastrointestinal environment. We aimed at investigating the effects of mannan on SBD-1 expression and the downstream signaling pathways stimulated in OREC. We cultured OREC; assessed the effects of mannan on SBD-1 expression by qPCR and ELISA; and then investigated the underlying signaling pathways using qPCR, ELISA, Western blotting, immunohistochemistry, and immunohistofluorescence. Interestingly, mannan markedly upregulated SBD-1 expression in a concentration- and time-dependent manner. Dectin-2 Mouse mAb, Syk specific inhibitor R406, and specific inhibitors of the p38, ERK1/2, JNK, and NF-κB pathways attenuated mannan-induced SBD-1 expression to varying degrees. These results demonstrate that SBD-1 is upregulated by mannan via the Dectin-2-Syk axis, and this is regulated to a large extent through the mitogen-activated protein kinase (MAPK) p38 and less so through the ERK1/2 and JNK or the NF-κB pathway. Our findings highlight the immunomodulatory effects of mannan on OREC in terms of mannan-induced SBD-1 expression.Electronic supplementary materialThe online version of this article (10.1186/s13567-019-0624-4) contains supplementary material, which is available to authorized users.

Effects of the Dectin-2/TNF-α Pathway on Ventricular Arrhythmia after Acute Myocardial Infarction in Mice

“…The expression levels of tumor necrosis factor- α (TNF- α ), interferon-gamma (IFN- γ ), interleukin (IL) 4, and IL-5 in plasma were determined by ELISA as per the ELISA kit instructions (MILLIPLEX multifactor detection kit, Merck Biotechnology Co., Ltd., Germany). A microplate reader was used to measure the OD value at 450 nm (1510, Thermo, USA), and the concentration was calculated by a standard curve [ 19 ].…”

Prebiotic effects of yeast mannan, which selectively promotes Bacteroides thetaiotaomicron and Bacteroides ovatus in a human colonic microbiota model

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Investigation of serum beta-defensin-1 level in calves with coccidiosis

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