Association Of Keap1-Nrf2-ARE Pathway With Deltamethrin Tolerance In Drosophila Kc Cells

Deltamethrin has been widely used in public health,veterinary medicine,especially in agriculture because of its good biological activity and environmental compatibility.It has become one of the pyrethroids widely used in the world,which has resulted in global resistance and extensive cross-resistance with other insecticides.Therefore,it is very important to study the resistance mechanism of deltamethrin.Keap1-Nrf2-ARE pathway is one of the most important endogenous antioxidant stress pathways known at present.Nrf2 transcription factor is uncoupled with Keap1 protein with conformational changes under the stimulation of reactive oxygen species(ROS),migrates to the nucleus,aggregates and binds to antioxidant elements,thus activating a large number of downstream antioxidant proteins and metabolic detoxification enzymes.A large number of studies have shown that besides reactive oxygen species,many exogenous toxic substances can also stimulate the expression of this pathway in the body.Previous experiments showed that deltamethrin could significantly increase the expression of Nrf2 gene in Drosophila Kc cells,and promote the translocation and accumulation of Nrf2 transcription factors into the nucleus.In this study,we compared the tolerance level of Drosophila Kc cells to deltamethrin under the condition of overexpression of Nrf2 and Keap1 genes or interference with Nrf2,and the effect of the changes of Nrf2 and Keap1 gene expression levels on the gene expression profile of cells.It was confirmed that the Keap1-Nrf2-ARE pathway was related to deltamethrin tolerance.The main results are as follows:1)Flow cytometry data showed that deltamethrin treatment of Drosophila Kc cells at 20 ppm for 24 hours could promote cell apoptosis.Overexpression of Nrf2 gene could reduce cell apoptosis caused by deltamethrin.Overexpression of Keap1 gene or interference with Nrf2 gene had the opposite effect.2)RNA-Seq analysis revealed that 268 genes in deltamethrin-stressed cells were expressed at different levels,including cytochrome P450 family genes,glutathione S-transferase family genes,ace gene for acetylcholinesterase synthesis,immune-related genes and genes related to cell cycle and epidermis formation.GO classification analysis of differentially expressed genes revealed that most of the genes were expressed at different levels.Because it belongs to the functional components of biological processes,it mainly participates in the processes of biological regulation,metabolism,detoxification,immunity and transport.3)In Keap1 overexpressed cells,deltamethrin stress significantly reduced the expression of many genes in cytochrome P450 family,and the expression of some genes related to human diseases and ncRNA also changed significantly.These results suggest that the Keap1-Nrf2-ARE pathway is associated with deltamethrin tolerance in Drosophila Kc cells.The results provide a new idea for further elucidating the complex mechanism of deltamethrin resistance.