Díaz-Murillo Violeta, Medina-Estrada Ivan, López-Meza Joel E, Ochoa-Zarzosa Alejandra
Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Km 9.5 Carr. Morelia-Zinapécuaro, Posta Veterinaria, C.P. 58893, Morelia, Michoacán, Mexico, Mexico.
Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Km 9.5 Carr. Morelia-Zinapécuaro, Posta Veterinaria, C.P. 58893, Morelia, Michoacán, Mexico, Mexico.
Peptides. 2016 Apr;78:109-18. doi: 10.1016/j.peptides.2016.02.008. Epub 2016 Mar 3.
β-Defensins are members of the antimicrobial peptide superfamily that are produced in various species from different kingdoms, including plants. Plant defensins exhibit primarily antifungal activities, unlike those from animals that exhibit a broad-spectrum antimicrobial action. Recently, immunomodulatory roles of mammal β-defensins have been observed to regulate inflammation and activate the immune system. Similar roles for plant β-defensins remain unknown. In addition, the regulation of the immune system by mammalian β-defensins has been studied in humans and mice models, particularly in immune cells, but few studies have investigated these peptides in epithelial cells, which are in intimate contact with pathogens. The aim of this work was to evaluate the effect of the chemically synthesized β-defensin γ-thionin from Capsicum chinense on the innate immune response of bovine mammary epithelial cells (bMECs) infected with Staphylococcus aureus, the primary pathogen responsible for bovine mastitis, which is capable of living within bMECs. Our results indicate that γ-thionin at 0.1 μg/ml was able to reduce the internalization of S. aureus into bMECs (∼50%), and it also modulates the innate immune response of these cells by inducing the mRNA expression (∼5-fold) and membrane abundance (∼3-fold) of Toll-like receptor 2 (TLR2), as well as by inducing genes coding for the pro-inflammatory cytokines TNF-α and IL-1β (∼14 and 8-fold, respectively) before and after the bacterial infection. γ-Thionin also induces the expression of the mRNA of anti-inflammatory cytokine IL-10 (∼12-fold). Interestingly, the reduction in bacterial internalization coincides with the production of other antimicrobial products by bMECs, such as NO before infection, and the secretion into the medium of the endogenous antimicrobial peptide DEFB1 after infection. The results from this work support the potential use of β-defensins from plants as immunomodulators of the mammalian innate immune response.
β-防御素是抗菌肽超家族的成员，在包括植物在内的不同界的各种物种中产生。与具有广谱抗菌作用的动物防御素不同，植物防御素主要表现出抗真菌活性。最近，已观察到哺乳动物β-防御素的免疫调节作用可调节炎症并激活免疫系统。植物β-防御素的类似作用仍然未知。此外，已在人类和小鼠模型中研究了哺乳动物β-防御素对免疫系统的调节，特别是在免疫细胞中，但很少有研究在上皮细胞中研究这些肽，上皮细胞与病原体密切接触。这项工作的目的是评估化学合成的来自中国辣椒的β-防御素γ-硫堇对感染金黄色葡萄球菌的牛乳腺上皮细胞（bMECs）先天免疫反应的影响，金黄色葡萄球菌是引起牛乳腺炎的主要病原体，能够在bMECs内存活。我们的结果表明，0.1μg/ml的γ-硫堇能够减少金黄色葡萄球菌进入bMECs的内化（约50%），并且它还通过诱导Toll样受体2（TLR2）的mRNA表达（约5倍）和膜丰度（约3倍）来调节这些细胞的先天免疫反应，以及在细菌感染前后诱导编码促炎细胞因子TNF-α和IL-1β的基因（分别约14倍和8倍）。γ-硫堇还诱导抗炎细胞因子IL-10的mRNA表达（约12倍）。有趣的是，细菌内化的减少与bMECs产生的其他抗菌产物一致，例如感染前的NO，以及感染后内源性抗菌肽DEFB1分泌到培养基中。这项工作的结果支持了植物β-防御素作为哺乳动物先天免疫反应免疫调节剂的潜在用途。
