Targeted Chemoproteomics Identifies COEAE6G Esterase Driving Insecticide Cross- Resistance in African Malaria Vector

Pyrethroid insecticide resistance in the primary malaria vector, Anopheles gambiae, poses a substantial challenge to ongoing control efforts in sub-Saharan Africa, where most malaria cases and deaths occur. To combat this challenge, newer chemicals, including pirimiphos-methyl (PM) are being used. To gain insight into how future resistance may develop to these compounds, a proactive chemical proteomics approach was developed using activity-based protein profiling (ABPP) in susceptible An. gambiae to identify enzymes interacting with pirimiphos-methyl (PM) and its toxic metabolite PMO. We discovered 18 serine hydrolases (SHs) as primary targets of PMO, including the carboxylesterase COEAE6G. Subsequent in vitro and in vivo validation confirmed that COEAE6G confers resistance to PM, as well as cross-resistance to malathion, permethrin and bendiocarb. This study underscores the utility of ABPP as a powerful tool for early detection of potential resistance markers, such as COEAE6G, enabling the development of effective resistance management strategies.