Research On The Relationship Between MiR-932 And Mosquito Resistance

Mosquitoes transmit a lot of pathogens,causing severe disease such as malaria,dengue fever,West Nile fever,Japanese encephalitis and filariasis,which threat public health worldwide.Therefore,it is imperative for controlling and preventing mosquito-borne diseases.However,due to the lack of effective vaccines and drugs,mosquito control relying on insecticides to reduce the number of mosquitoes became a main strategy.Chemical control has always been an important means of mosquito control strategy,for its killing speed and convenient characteristics.But continuous and lasting application of insecticides has led to a constant increasing resistance,which makes anti-mosquito strategies more challenging.Insecticide resistance arises from complex polygenic inheritance and many genes involved.These genes can be regulated at transcriptional and post-transcriptional levels and microRNA(miRNA)is known to be a post-transcriptional gene regulator.Here,according to our previous study,we identified many different expressed miRNAs in deltamethrin-resistant strain(DR)and deltamethrin-susceptible strain(DS)of Culex pipiens pallens.Among these miRNAS,miR-932 is down-regulated in DS-strain,suggesting that this miRNA could involve in the regulation of pyrethroid resistance.In this study,we examine the role of miR-932 and find its target,CpCPR5,and investigate their regulatory mechanism in pyrethroid resistance.Target prediction suggested that the seed sequence of miR-932 paired up with the 3’UTR sequence of CpCPR5.Quantitative real-time PCR analysis showed that miR-932 was highly expressed in DR-strain,while CpCPR5 was highly expressed in DS-strain.The opposite phenomenon suggested that CpCPR5 could be the target gene of miR-932.The luciferase assay showed that miR-932 greatly inhibited the activity of 3’UTR construct in a dose-dependent manner,indicating that CpCPR5 was a direct target of miR-932.The group injected with dsRNA showed a reduction in CpCPR5 expression of 44%compared to the control group,and based on the CDC Bottle Bioassay,the group injected with dsRNA had a lower mortality than the other two groups.All the results suggested that mosquitoes were more resistant to deltamethrin after CpCPR5 knockdown and CpCPR5 could affect deltamethrin resistance in mosquitoes.The expression level of CpCPR5 was significantly lower in the group injected with miR-932 mimic than in the other groups.And the CDC Bottle Bioassay showed that the miR-932 mimic injected group had a lower mortality than NC and DEPC groups.On the other hand,when knockdown miR-932 in DR-strain,the expression level of CpCPR5 increased correspondingly.The CDC Bottle Bioassay exhibited that the mosquitoes injected with inhibitor were more susceptible than those of the other groups.In conclusion,our study demonstrates that miR-932 participate in the regulation of pyrethroid resistance of mosquitoes by targeting CpCPR5.And the role of miR-932 in pyrethroid resistance provide novel insights into the mechanism of insecticide resistance.