Veterinary Medicine College of Inner Mongolia Agricultural University, Hohhot, 010018, China.
Key Laboratory of Clinical Diagnosis and Treatment Technology in Animal Disease, Ministry of Agriculture, Hohhot, 010018, China.
Vet Res. 2019 Feb 4;50(1):8. doi: 10.1186/s13567-019-0624-4.
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.
绵羊的瘤胃上皮作为与环境的免疫界面，分泌具有杀菌功能的抗菌肽，以抵抗各种病原体。绵羊β-防御素-1（SBD-1）是一种抗菌肽，它是由绵羊瘤胃上皮细胞（OREC）在微生物感染时分泌的。甘露聚糖是酿酒酵母细胞壁的主要成分，可刺激先天和调节性免疫反应，从而改善胃肠道环境。我们旨在研究甘露聚糖对 OREC 中 SBD-1 表达和下游信号通路的影响。我们培养 OREC；通过 qPCR 和 ELISA 评估甘露聚糖对 SBD-1 表达的影响；然后通过 qPCR、ELISA、Western blot、免疫组织化学和免疫荧光来研究潜在的信号通路。有趣的是，甘露聚糖以浓度和时间依赖的方式显著上调 SBD-1 的表达。Dectin-2 小鼠 mAb、Syk 特异性抑制剂 R406 以及 p38、ERK1/2、JNK 和 NF-κB 途径的特异性抑制剂在不同程度上减弱了甘露聚糖诱导的 SBD-1 表达。这些结果表明，SBD-1 通过 Dectin-2-Syk 轴被甘露聚糖上调，这在很大程度上通过丝裂原激活蛋白激酶（MAPK）p38 调节，而通过 ERK1/2 和 JNK 或 NF-κB 途径调节的程度较小。我们的研究结果强调了甘露聚糖对 OREC 的免疫调节作用，即甘露聚糖诱导 SBD-1 的表达。
