Li Ting, Liu Nannan
Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
Biochem Biophys Rep. 2017 Aug 19;12:12-19. doi: 10.1016/j.bbrep.2017.08.010. eCollection 2017 Dec.
This study explores the role of G-protein-coupled receptor-intracellular signaling in the development of P450-mediated insecticide resistance in mosquitoes, , focusing on the essential function of the GPCRs and their downstream effectors of Gs alpha subunit protein (Gαs) and adenylyl cyclase (ACs) in P450-mediated insecticide resistance of mosquitoes. Our RNAi-mediated functional study showed that knockdown of Gαs caused the decreased expression of the downstream effectors of ACs and PKAs in the GPCR signaling pathway and resistance P450 genes, whereas knockdown of ACs decreased the expression of PKAs and resistance P450 genes. Knockdown of either Gαs or ACs resulted in an increased susceptibility of mosquitoes to permethrin. These results add significantly to our understanding of the molecular basis of resistance P450 gene regulation through GPCR/Gαs/AC/cAMP-PKA signaling pathways in the insecticide resistance of mosquitoes. The temporal and spatial dynamic analyses of GPCRs, Gαs, ACs, PKAs, and P450s in two insecticide resistant mosquito strains revealed that all the GPCR signaling pathway components tested, namely GPCRs, Gαs, ACs and PKAs, were most highly expressed in the brain for both resistant strains, suggesting the role played by these genes in signaling transduction and regulation. The resistance P450 genes were mainly expressed in the brain, midgut and malpighian tubules (MTs), suggesting their critical function in the central nervous system and importance for detoxification. The temporal dynamics analysis for the gene expression showed a diverse expression profile during mosquito development, indicating their initially functional importance in response to exposure to insecticides during their life stages.
本研究探讨了G蛋白偶联受体-细胞内信号传导在蚊子P450介导的杀虫剂抗性发育中的作用，重点关注GPCR及其Gsα亚基蛋白（Gαs）和腺苷酸环化酶（ACs）的下游效应器在蚊子P450介导的杀虫剂抗性中的重要功能。我们的RNAi介导的功能研究表明，敲低Gαs会导致GPCR信号通路中ACs和PKAs的下游效应器以及抗性P450基因的表达降低，而敲低ACs会降低PKAs和抗性P450基因的表达。敲低Gαs或ACs都会导致蚊子对氯菊酯的敏感性增加。这些结果显著增加了我们对蚊子杀虫剂抗性中通过GPCR/Gαs/AC/cAMP-PKA信号通路调控抗性P450基因分子基础的理解。对两种抗杀虫剂蚊子品系中GPCRs、Gαs、ACs、PKAs和P450s的时空动态分析表明，所测试的所有GPCR信号通路成分，即GPCRs、Gαs、ACs和PKAs，在两种抗性品系的大脑中表达最高，表明这些基因在信号转导和调控中发挥的作用。抗性P450基因主要在大脑、中肠和马氏管中表达，表明它们在中枢神经系统中的关键功能以及对解毒的重要性。基因表达的时间动态分析显示，在蚊子发育过程中表达谱多样，表明它们在蚊子生命阶段对杀虫剂暴露反应中的初始功能重要性。
