Department of Plant Medicals, Andong National University, Andong, 36729, Korea.
Sci Rep. 2019 Mar 21;9(1):4988. doi: 10.1038/s41598-019-41541-2.
Cellular immunity in insects is accompanied by change in hemocyte shape. This study hypothesizes that cytoskeletal rearrangement is accompanied by transmembrane water transport to change cell volume, thus changing cell shape. A water-transporting pore (=aquaporin:AQP) has been identified in the beet armyworm, Spodoptera exigua. Its expression was detected in all developmental stages and tissues, although its transcription levels were different between biotic and abiotic conditions. Heterologous expression of Se-AQP in Sf9 cells showed that Se-AQP was localized on cell membrane. RNA interference (RNAi) using double-stranded RNA effectively suppressed its transcript levels. Under different ionic concentrations, hemocytes of RNAi-treated larvae did not change cell volume presumably due to malfunction in water transportation. Se-AQP might participate in glycerol transport because up-regulation of hemolymph glycerol titer after rapid cold-hardening was prevented by RNAi treatment against Se-AQP expression. The inhibitory effect of RNAi treatment on change of cell shape significantly impaired cellular immune responses such as phagocytosis and nodule formation upon bacterial challenge. RNAi treatment also significantly interfered with immature development of S. exigua. These results indicate that Se-AQP plays a crucial role in cell shape change that is required for cellular immunity and other physiological processes.
昆虫的细胞免疫伴随着血细胞形状的变化。本研究假设细胞骨架重排伴随着跨膜水转运，以改变细胞体积，从而改变细胞形状。在甜菜夜蛾 Spodoptera exigua 中已鉴定出一种水转运孔（=水通道蛋白：AQP）。它在所有发育阶段和组织中都有表达，尽管其转录水平在生物和非生物条件之间存在差异。在 Sf9 细胞中异源表达 Se-AQP 表明 Se-AQP 定位于细胞膜上。双链 RNA 的 RNAi 有效抑制了其转录水平。在不同的离子浓度下，RNAi 处理的幼虫的血细胞体积没有变化，这可能是由于水转运功能障碍所致。Se-AQP 可能参与甘油运输，因为 RNAi 处理对 Se-AQP 表达的抑制作用阻止了快速冷驯化后血淋巴甘油滴度的上调。RNAi 处理对细胞形状变化的抑制作用显著损害了细胞免疫反应，如细菌攻击时的吞噬作用和结节形成。RNAi 处理还显著干扰了甜菜夜蛾的不成熟发育。这些结果表明，Se-AQP 在细胞形状变化中起关键作用，这是细胞免疫和其他生理过程所必需的。
