Geng Tao, Lv Ding-Ding, Huang Yu-Xia, Hou Cheng-Xiang, Qin Guang-Xing, Guo Xi-Jie
Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, China.
Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China.
Gene. 2016 Dec 20;595(1):69-76. doi: 10.1016/j.gene.2016.09.043. Epub 2016 Sep 28.
Innate immunity was critical in insects defensive system and able to be induced by Janus kinase/signal transducer and activator of transcription cascade transduction (JAK/STAT) signaling pathway. Currently, it had been identified many JAK/STAT signaling pathway-related genes in silkworm, but little function was known on insect innate immunity. To explore the roles of JAK/STAT pathway in antifungal immune response in silkworm (Bombyx mori) against Beauveria bassiana infection, the expression patterns of B. mori C-type lectin 5 (BmCTL5) and genes encoding 6 components of JAK/STAT signaling pathway in silkworm challenged by B. bassiana were analyzed using quantitative real time PCR. Meanwhile the activation of JAK/STAT signaling pathway by various pathogenic micro-organisms and the affect of JAK/STAT signaling pathway inhibitors on antifungal activity in silkworm hemolymph was also detected. Moreover, RNAi assay of BmCTL5 and the affect on expression levels of signaling factors were also analyzed. We found that JAK/STAT pathway could be obviously activated in silkworm challenged with B. bassiana and had no response to bacteria and B. mori cytoplasmic polyhedrosis virus (BmCPV). However, the temporal expression patterns of JAK/STAT signaling pathway related genes were significantly different. B. mori downstream receptor kinase (BmDRK) might be a positive regulator of JAK/STAT signaling pathway in silkworm against B. bassiana infection. Moreover, antifungal activity assay showed that the suppression of JAK/STAT signaling pathway by inhibitors could significantly inhibit the antifungal activity in hemolymph and resulted in increased sensitivity of silkworm to B. bassiana infection, indicating that JAK/STAT signaling pathway might be involved in the synthesis and secretion of antifungal substances. The results of RNAi assays suggested that BmCTL5 might be one pattern recognition receptors for JAK/STAT signaling pathway in silkworm. These findings yield insights for better understand the molecular mechanisms of JAK/STAT signaling pathway in antifungal immune response in silkworm.
先天免疫在昆虫防御系统中至关重要，且能够被Janus激酶/信号转导及转录激活因子级联转导（JAK/STAT）信号通路所诱导。目前，在家蚕中已鉴定出许多与JAK/STAT信号通路相关的基因，但对其在昆虫先天免疫中的功能了解甚少。为探究JAK/STAT通路在家蚕抗白僵菌感染的抗真菌免疫反应中的作用，采用实时定量PCR分析了白僵菌感染家蚕后家蚕C型凝集素5（BmCTL5）及编码JAK/STAT信号通路6个组分的基因的表达模式。同时，还检测了各种病原微生物对JAK/STAT信号通路的激活情况以及JAK/STAT信号通路抑制剂对家蚕血淋巴中抗真菌活性的影响。此外，还分析了BmCTL5的RNA干扰试验及其对信号因子表达水平的影响。我们发现，用白僵菌攻击家蚕时，JAK/STAT通路可被明显激活，而对细菌和家蚕细胞质多角体病毒（BmCPV）无反应。然而，JAK/STAT信号通路相关基因的时间表达模式存在显著差异。家蚕下游受体激酶（BmDRK）可能是家蚕抵御白僵菌感染时JAK/STAT信号通路的正调控因子。此外，抗真菌活性试验表明，抑制剂对JAK/STAT信号通路的抑制可显著抑制血淋巴中的抗真菌活性，并导致家蚕对白僵菌感染的敏感性增加，这表明JAK/STAT信号通路可能参与抗真菌物质的合成与分泌。RNA干扰试验结果表明，BmCTL5可能是家蚕JAK/STAT信号通路的一种模式识别受体。这些发现有助于更好地理解JAK/STAT信号通路在家蚕抗真菌免疫反应中的分子机制。
