Chemical Signaling Regulates Axon Regeneration via the GPCR-Gqα Pathway in .

Chemical communication controls a wide range of behaviors via conserved signaling networks. Axon regeneration in response to injury is determined by the interaction between the extracellular environment and intrinsic growth potential. In this study, we investigated the role of chemical signaling in axon regeneration in We find that the enzymes involved in ascaroside pheromone biosynthesis, ACOX-1.1, ACOX-1.2, and DAF-22, participate in axon regeneration by producing a dauer-inducing ascaroside, ascr#5. We demonstrate that the chemoreceptor genes, and , which encode G-protein-coupled receptors for ascr#5, are required for adult-specific axon regeneration. Furthermore, the activating mutation in encoding Gqα suppresses axon regeneration defective phenotype in and mutants. Therefore, the ascaroside signaling system provides a unique example of a signaling molecule that regulates the regenerative pathway in the nervous system. In , axon regeneration is positively regulated by the EGL-30 Gqα-JNK MAP kinase cascade. However, it remains unclear what signals activate the EGL-30 pathway in axon regeneration. Here, we show that SRG-36 and SRG-37 act as upstream G-protein-coupled receptors (GPCRs) that activate EGL-30. secretes a family of small-molecule pheromones called ascarosides, which serve various functions in chemical signaling. SRG-36 and SRG-37 are GPCRs for the dauer-inducing ascaroside ascr#5. Consistent with this, we found that ascr#5 activates the axon regeneration pathway via SRG-36/SRG-37 and EGL-30. Thus, ascaroside signaling promotes axon regeneration by activating the GPCR-Gqα pathway.