Various Eicosanoids Modulate the Cellular and Humoral Immune Responses of the Beet Armyworm, Spodoptera exigua-猫眼课题宝

各种类二十烷酸调节甜菜夜蛾的细胞和体液免疫反应

DOI：

发表时间：

2009

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Bioscience, biotechnology and biochemistry

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作者：

S. Shrestha;Yonggyun Kim

环氧合酶（考克斯）和脂氧合酶（LOX）可催化C20脂肪酸氧化生成类花生酸，在昆虫免疫应答中发挥重要作用。尽管它们在昆虫免疫中起着关键作用，但很少有关于不同类花生酸对免疫应答的独特作用的研究。本研究分析了甜菜夜蛾的细胞和体液免疫反应，甜菜夜蛾，使用七个类花生酸选自两个主要的类花生酸亚群：前列腺素（PG）和白三烯（LT），分别来自催化活性的考克斯和LOX。在细菌挑战后，所有七种类花生酸（PGA 1、PGB 2、PGD 2、PGE 1、PGE 2、PGF 1 α和LTB 4）在存在地塞米松（一种类花生酸生物合成抑制剂）的情况下均显著诱导血细胞生成和吞噬作用。然而，只有前列腺素诱导细胞溶解的oenocytoids释放酚氧化酶原，这导致酚氧化酶活性的增加。这七个类花生酸还诱导体液免疫相关基因的表达，包括酚氧化酶原，丝氨酸蛋白酶抑制剂，多巴脱羧酶，天蚕素，和溶菌酶，其中PGB 2和PGE 1不诱导酚氧化酶原的基因表达。为了了解不同类二十烷酸之间的相互作用，将这些类二十烷酸的混合效应与其单独的类二十烷酸对响应细菌挑战介导结节形成的效应进行了比较。所有6种单一PG均显示结节形成以剂量依赖性方式增加，不同类型之间无显著差异。LTB4在介导细胞免疫应答方面比测试的PG更有效。在低剂量下，两种类花生酸的所有组合对结节形成显示出显著的加性效应。提示血细胞、脂肪体等免疫靶细胞是血吸虫感染的重要靶细胞。甜菜碱能对不同的考克斯和LOX产物产生应答，从而表达细胞和体液免疫应答，它们对促凝作用的重叠和累加效应表明，在靶细胞中，这些类花生酸共享一个假设的共同类花生酸信号通路。

Cyclooxygenase (COX) and lipoxygenase (LOX) can catalyze the oxidation of C20 fatty acids to produce certain eicosanoids, which play roles in mediating immune responses in insects. Despite their critical role in insect immunity, there have been few studies of the unique effects of different eicosanoids on immune responses. This study analyzed cellular and humoral immune responses of the beet armyworm, Spodoptera exigua, using seven eicosanoids selected from two major eicosanoid subgroups: prostaglandin (PG) and leukotriene (LT), derived from catalytic activities of COX and LOX respectively. Upon bacterial challenge, all seven eicosanoids (PGA1, PGB2, PGD2, PGE1, PGE2, PGF1α, and LTB4) significantly induced hemocyte nodulation and phagocytosis in the presence of dexamethasone, an eicosanoid biosynthesis inhibitor. However, only PGs induced cell lysis of oenocytoids to release prophenoloxidase, which resulted in an increase in phenoloxidase activity. These seven eicosanoids also induced expression of humoral immune-associated genes, including prophenoloxidase, serpin, dopa decarboxylase, cecropin, and lysozyme, in which PGB2 and PGE1 did not induce gene expression of prophenoloxidase. To understand the interactions between different eicosanoids, mixture effects of these eicosanoids were compared with their individual eicosanoid effects on mediating nodule formation in response to bacterial challenge. All six single PGs showed increases in nodule formation in a dose-dependent manner without significant difference among the different types. LTB4 was more potent than the tested PGs in mediating the cellular immune response. At low doses, all combinations of two eicosanoids showed significant additive effects on nodule formation. These results indicate that immune target cells, such as hemocyte and fat body, of S. exigua can respond to different COX and LOX products to express cellular and humoral immune responses, and their overlapping, additive effects on nodulation suggest that in target cells, these eicosanoids share a hypothetical common eicosanoid signal pathway.