Ji Xiao Guo, Huang Ji Hong, Hui Ming, Zhang Ya Qi, Zhao Yi
School of Biological Engineering, Henan University of Technology, Lianhua Street, Zhengzhou, 450001, China.
Protein Pept Lett. 2018 Feb 8;24(12):1148-1165. doi: 10.2174/0929866524666171026123054.
Wheat germ, one of the byproducts of flour milling, contains abundant physiologically active components. Globulins in wheat germ are a class of high-quality functional proteins and have received widespread attention. However, the composition of wheat germ globulin（ WGG）and the structure of the typical proteins have not yet been proved. The immunological activities and immune mechanisms of the WGG have not yet been revealed in vivo.
The proteomic analysis of WGG and the structure simulation of typical proteins were studied. The immunoregulatory effects of WGG on immunosuppressed mice induced by cyclophosphamide were investigated, and the immunological activities of WGG were explored.
The main components, functions, and metabolic signaling pathways of WGG were analyzed through a combination of LC-MS method and bioinformatics. The structure of WGG was predicted via the Phyre2 tool. Immunosuppression in mice was induced by cyclophosphamide. After an intraperitoneal injection of WGG for 10 days, organ indexes and pathological changes of mice were detected. The T-cell subgroups in peripheral blood were analyzed via flow cytometry. Levels of IL-2, IL-4, TNF-α, and IFN-γ were evaluated through ELISA. The mRNA expression levels of T-Bet and GATA-3 were measured using real-time PCR.
The results indicated that the main functional components of WGG were wheat germ globulins, histones, heat shock proteins (HSPs), and other functional proteins. Wheat germ globulins and HSPs were the major immune components of WGG. WGG significantly reduced immunosuppression in the spleen and thymus indexes (P<0.01), and mitigated the damage caused by cyclophosphamide in the spleen and thymus. Moreover, WGG significantly increased the CD4+/CD8+ of the immunosuppressed mice (P<0.01), restored Th1/Th2 imbalance (P < 0.01), enhanced the content of IL-2 and IL-4 (P<0.01), and modified the abnormal secretion of cytokines. WGG also observably reduced the mRNA expression of T-Bet and GATA-3 (P<0.01). These results manifested that WGG components improved the immune system. The action mechanisms might be related to the variation of Th1/Th2 cells resulted from the control of the mRNA expression levels of T-Bet and GATA-3.
The wheat germ histone family and the HSPs are the major immune components of WGG. It may be the immune mechanism of WGG that these globulins affect the differentiation of Th1/Th2 cells via controlling the mRNA expression levels of related genes. The results indicated the potential application of WGG or its further purified products as a superior plant-derived immunomodulator in the future.
小麦胚芽是面粉加工的副产品之一，含有丰富的生理活性成分。小麦胚芽球蛋白是一类优质的功能蛋白，受到广泛关注。然而，小麦胚芽球蛋白（WGG）的组成及典型蛋白的结构尚未明确。WGG的免疫活性及免疫机制在体内也尚未揭示。
研究WGG的蛋白质组学分析及典型蛋白的结构模拟。探讨WGG对环磷酰胺诱导的免疫抑制小鼠的免疫调节作用，探究WGG的免疫活性。
通过液相色谱-质谱联用（LC-MS）方法与生物信息学相结合，分析WGG的主要成分、功能及代谢信号通路。利用Phyre2工具预测WGG的结构。用环磷酰胺诱导小鼠免疫抑制。腹腔注射WGG 10天后，检测小鼠的器官指数和病理变化。通过流式细胞术分析外周血中的T细胞亚群。采用酶联免疫吸附测定（ELISA）法评估白细胞介素-2（IL-2）、IL-4、肿瘤坏死因子-α（TNF-α）和干扰素-γ（IFN-γ）的水平。用实时荧光定量聚合酶链反应（PCR）检测T盒转录因子（T-Bet）和GATA结合蛋白3（GATA-3）的mRNA表达水平。
结果表明，WGG的主要功能成分是小麦胚芽球蛋白、组蛋白、热休克蛋白（HSPs）和其他功能蛋白。小麦胚芽球蛋白和HSPs是WGG的主要免疫成分。WGG显著降低了脾脏和胸腺指数的免疫抑制作用（P<0.01），减轻了环磷酰胺对脾脏和胸腺造成的损伤。此外，WGG显著提高了免疫抑制小鼠的CD4+/CD8+比值（P<0.01），恢复了Th1/Th2失衡（P<0.01），提高了IL-2和IL-4的含量（P<0.01），并改善了细胞因子的异常分泌。WGG还显著降低了T-Bet和GATA-3的mRNA表达（P<0.01）。这些结果表明WGG成分改善了免疫系统。作用机制可能与通过控制T-Bet和GATA-3的mRNA表达水平导致的Th1/Th2细胞变化有关。
小麦胚芽组蛋白家族和HSPs是WGG的主要免疫成分。这些球蛋白可能通过控制相关基因的mRNA表达水平影响Th1/Th2细胞的分化，这可能是WGG的免疫机制。结果表明WGG或其进一步纯化的产品未来作为一种优质植物源免疫调节剂具有潜在的应用价值。
