Liu Weimin, Zhao Yiyan, Zhao Xiaoming, Guo Hongfang, Yang Yang, Moussian Bernard, Zhang Jianzhen
Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, Shanxi University, Shanxi, China.
Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, Shanxi University, Shanxi, China.
Insect Biochem Mol Biol. 2025 Jun;181:104314. doi: 10.1016/j.ibmb.2025.104314. Epub 2025 Apr 23.
Lipids are important components of the insect cuticle protecting against desiccation and xenobiotic penetration. Delivery of lipids to the cuticular surface occurs through pore canals, which are a nano-canal system formed by the epidermis, running through the procuticle and terminating at the epicuticle, where they ramify as wax-canals. The molecular mechanisms of cuticular lipids deposition in insects are poorly understood. Here, we identified the pore canal protein Snsl (Snustorr snarlik) in the migratory locust Locusta migratoria (LmSnsl) and investigated its function in cuticular lipid transport and cuticle barrier construction. We found that LmSnsl was specifically expressed in the integument and had a high expression level before ecdysis when a new cuticle is formed. Silencing of LmSnsl by RNA interference (RNAi) caused a lethal phenotype during or shortly after molting. In addition, RNAi against LmSnsl resulted in a decrease in cuticular lipids and in the accumulation of internal lipids. The pore canals of dsLmSnsl animals are deformed and contain less luminal material. Furthermore, we found that cuticle permeability to xenobiotics was enhanced in dsLmSnsl-treated nymphs that were, consistently, more susceptible to insecticides. These animals were also prone to pathogen invasion suggesting that cuticle lipids act in pathogen defense. Taken together, our results indicate that the locust Snsl protein is needed for pore canal integrity required for the transport of lipids from the epidermis to the cuticle to constitute a barrier against xenobiotics and pathogens.
脂质是昆虫表皮的重要组成部分，可防止脱水和异源物质渗透。脂质通过孔道输送到表皮表面，孔道是由表皮形成的纳米管道系统，贯穿前表皮并终止于外表皮，在外表皮处分支形成蜡道。昆虫表皮脂质沉积的分子机制尚不清楚。在这里，我们在飞蝗Locusta migratoria中鉴定了孔道蛋白Snsl（Snustorr snarlik，即LmSnsl），并研究了其在表皮脂质运输和表皮屏障构建中的功能。我们发现LmSnsl在体壁中特异性表达，在蜕皮形成新表皮之前表达水平很高。通过RNA干扰（RNAi）沉默LmSnsl会在蜕皮期间或蜕皮后不久导致致死表型。此外，针对LmSnsl的RNAi导致表皮脂质减少和内部脂质积累。dsLmSnsl处理的动物的孔道变形，管腔内物质减少。此外，我们发现dsLmSnsl处理的若虫对异源物质的表皮通透性增强，这些若虫对杀虫剂也更敏感。这些动物也容易受到病原体入侵，这表明表皮脂质在病原体防御中起作用。综上所述，我们的结果表明，蝗虫的Snsl蛋白是孔道完整性所必需的，而孔道完整性是脂质从表皮运输到表皮以构成抵御异源物质和病原体的屏障所必需的。
