柑橘小实蝇tachykinin和natalisin的生理功能及其受体药靶潜力评估

Because of its capacity for adaptation to new environments and infest new areas, the oriental fruit fly Bactrocera dorsalis, causes severe economic losses to more than 250 species of fruits and vegetables worldwide. Now it has been considered as the biggest threat for the citrus industry. Rapid development of the insecticide resistance and significant increases in the geographical distribution makes this notorious pest more and more difficult to control. Therefore, it is very urgent to find new targets for the development of novel insecticide to control this pest. Neuropeptides are major controllers of various physiological and developmental events in insects, such as metabolism, reproduction, diapause, molting, growth, and metamorphosis. Because of their essential functions in various life stages, the neuropeptidergic signaling systems are considered as potential targets for development of novel insecticides. Disruption of the signaling systems by using chemical agonists or antagonists may lead to disruption of critical functions and increase mortality among pest insects. Among more than 40 different types of neuropeptides in insects, tachykinin (TRP) is a neuropeptide that has been shown to be involved in numerous important physiological processes in many insects, such as muscle contraction in Locust, feeding behavior in Spodoptera, and olfactory reception, stress induced insulin expression, male-specific aggressive arousal in Drosophila. Recently, natalisin (NTL), a novel tachykinin-like signaling system has been discovered and shown to be regulating mating behavior and female fecundity in insects. Thererfore, the current study will be focusing on elucidating the important physiological functions of tachykinin and natalisin in B. dorsalis, utilizing advanced molecular techniques. The potential of these two systems serving as insecticide targets will be further assessed. Subsequently, the agonists and antagonists screening system for the TRPr and NTLr will be established to find small molecules that can disrupt the neural signaling. The results will expand our knowledge on the functions of TRPs and NTLs in insects as well as the mechanisms of behavior regulation by neuropeptides in insects. Furthermore, the properties of ligand interaction with the target receptor lays a foundation for rational design of peptidomimetics and potentially simple chemical compounds which could serve as the lead compounds for novel insect control agents development.

小实蝇是柑橘产业的巨大威胁，由于适生范围陡增、抗药性发展迅速、诱杀效果不明显等原因，其危害愈演愈烈、防治越来越难。面对防控困局，探索新靶标、开发新型控制剂已迫在眉睫！昆虫神经肽是多细胞生物体内重要信使，调控着多种关键生理过程，如生长发育、生殖及行为等。因其重要作用，以昆虫神经肽系统为靶标创制新药来控制害虫的新思路越来越受到重视。已有研究表明速激肽在许多昆虫中均具有重要的生理功能；最近，一个全新的、与速激肽类似的神经肽Natalisin被发现参与调控昆虫生殖行为。因此，本研究将探索这两种神经肽在柑橘小实蝇体内的重要生理功能，系统评价它们作为杀虫剂靶标的潜力，并建立其受体的激动剂、拮抗剂筛选体系以期获得具有生物活性的小分子化合物。研究结果不仅将丰富我们对昆虫Natalisin、速激肽功能的认识，促进理解神经肽调控昆虫行为的神经生理学机制，还将为新型害虫特异、环境友好型农药的创制提供理论依据。

柑橘小实蝇是柑橘产业的巨大威胁，由于适生范围陡增、抗药性发展迅速、诱杀效果不明显等原因，其危害愈演愈烈、防治越来越难。面对防控困局，探索新靶标、开发新型控制剂已迫在眉睫！昆虫神经肽是多细胞生物体内重要信使，调控着多种关键生理过程，如生长发育、生殖及行为等，以昆虫神经肽系统为靶标创制新药来控制害虫的新思路越来越受到重视。本项目以橘小实蝇为研究对象，利用分子克隆、qPCR、原位杂交、免疫组织化学、RNAi、行为学观察、哺乳动物细胞异源表达以及基于细胞内钙流的GPCR活性测定方法等多种手段探索Natalisin、Tachykinin、Adipokinetic hormone、Corazonin、ETH和sNPF六种神经肽信号传递系统对柑橘小实蝇生命活动的调控作用、揭示其介导的重要的生理功能。. 借助本项目的支持，经过四年的努力探索和研究，项目负责人及其小组成员在基因组水平上鉴定注释了橘小实蝇的神经肽基因，利用比较基因组学、转录组学手段分析了橘小实蝇神经肽与模式昆虫神经肽种类及结构的差异，为研究橘小实蝇行为的分子生理学机制奠定了坚实基础。. 研究确定了ETH通过ETHR-A调控橘小实蝇幼虫的两次生理蜕皮；证明了Corazonin信号系统可通过影响蛹壳的形成和黑化进而调控橘小实蝇幼虫-蛹的转化。该研究不但发掘了橘小实蝇幼虫生长发育以及变态发育过程中重要的神经肽信号传递系统，还揭示了这些神经肽信号的受体具有明显的药靶潜力，为开发实蝇类害虫新型控制剂提供理论参考。. 研究发现了AKH信号传递系统通过控制甘油三酯的代谢，从而调控橘小实蝇雄虫飞行及交配所需能量供应，同时还发现Natalisin信号传递系统调控橘小实蝇的交配成功率。. 首次发现Tachykinin信号系统在正常饲喂条件下调节橘小实蝇的嗅觉敏感性；但在饥饿条件Tachykinin信号系统并不发挥作用，而由sNPF信号传递系统介入并调控其嗅觉的敏感性。因此，该研究成果不仅帮助人们从崭新的角度认识昆虫中枢神经系统中神经肽信号传递系统对嗅觉行为的调控作用及分子机制，更开辟了一个崭新的昆虫嗅觉信号处理及调节机制研究领域。