The AMPK-FOXO signaling regulates the transcriptional response of 4EBP to pesticide stress in Tribolium castaneum

The eukaryotic initiation factor 4E-binding protein (4EBP) regulates protein synthesis by suppressing cap-dependent translation, the most energy-consuming process in the cell. While transcriptional and post-translational modulation of 4EBP has been extensively studied in mammals, its roles in response to pesticide stress in insects remain poorly understood. In this study, we identified and cloned the Tc4EBP gene from Tribolium castaneum. RT-qPCR analysis revealed that the expression level of Tc4EBP increased with the development time during larval, pupal and adult stages. RNA interference (RNAi) experiment showed that silencing Tc4EBP through dsRNA injection decreased pupation and eclosion rates of the beetles. Additionally, the mRNA level of Tc4EBP was significantly induced by deltamethrin treatment, and knockdown of Tc4EBP significantly increased susceptibility of the beetles to deltamethrin and enhanced deltamethrin-induced ATP depletion. Notably, knockdown of TcFOXO and TcAMPKα significantly downregulated the expression level of Tc4EBP and attenuated its induction by deltamethrin. Furthermore, knockdown of TcFOXO prevented the induction of Tc4EBP by treatment with the AMPK activator AICAR. This study establishes Tc4EBP is involved in development of T. castaneum, and TcAMPK-TcFOXO signaling positively regulated Tc4EBP transcription in response to deltamethrin treatment, providing evidence of a survival strategy under pesticide stress via inhibition of translation.