Prostaglandins (PGs) mediate various physiological processes in insects and other invertebrates, but there is very little information on PG receptors. This study identified a PGE₂ receptor (SePGE₂R) in the lepidopteran insect, Spodoptera exigua, and addressed its functional association with cellular immunity, development, and reproduction. SePGE₂R is expressed in most developmental stages and tissues. After SePGR₂R expression knock down by RNA interference (RNAi), larval nodule formation (clears bacterial infections from circulating hemolymph) was severely suppressed coupled with reduced F-actin growth in hemocytes. Treating female adults with RNAi prevented nurse cell dumping in follicles and interfered with oocyte development. SePGE₂R was heterologously expressed in Sf9 cells, in which the endogenous S. frugiperda PGE₂R was knocked down by small interfering RNA. This transiently expressed SePGE₂R responded to PGE₂, but not other PGs, with dose-dependent up-regulation of intracellular cAMP concentrations. Treating S. exigua larvae with PGE₂ led to activation of a trimeric Gαs subunit, protein kinase A (PKA), and Rho family small intracellular G proteins in hemocytes. A deletion mutant of SePGE₂R was generated using CRISPR/Cas9 which exhibited severely retarded larval development and adult reproduction. We infer that PGE₂R mediates insect immune and reproductive processes via a PKA signal pathway.

前列腺素 (PGs) 介导昆虫和其他无脊椎动物的各种生理过程，但关于 PG 受体的信息很少。该研究在鳞翅目昆虫Spodoptera exigua 中鉴定了 PGE ₂受体 (SePGE ₂ R) ，并解决了其与细胞免疫、发育和繁殖的功能关联。SePGE ₂ R在大多数发育阶段和组织中表达。在SePGR ₂ R 之后RNA 干扰 (RNAi) 表达敲低，幼虫结节形成（清除循环血淋巴中的细菌感染）受到严重抑制，同时血细胞中 F-肌动蛋白生长减少。用 RNAi 治疗成年女性可防止卵泡中的护士细胞倾倒并干扰卵母细胞发育。SePGE ₂ R在 Sf9 细胞中异源表达，其中内源性草地贪夜蛾 PGE ₂ R被小干扰 RNA 击倒。这种瞬时表达的SePGE ₂ R对PGE _{2 有反应}，但对其他PG 没有反应，细胞内cAMP 浓度呈剂量依赖性上调。用 PGE处理甜菜幼虫₂导致血细胞中三聚体 Gαs 亚基、蛋白激酶 A (PKA) 和 Rho 家族小细胞内 G 蛋白的激活。使用 CRISPR/Cas9 产生SePGE ₂ R 的缺失突变体，其表现出幼虫发育和成虫繁殖严重迟缓。我们推断 PGE ₂ R 通过 PKA 信号通路介导昆虫免疫和繁殖过程。