Neuropeptide signaling and SKN-1 orchestrate differential responses of the proteostasis network to dissimilar proteotoxic insults

Abstract

The protein homeostasis (proteostasis) network (PN) encompasses mechanisms that maintain proteome integrity by controlling various biological functions. Loss of proteostasis leads to toxic protein aggregation (proteotoxicity), which underlies the manifestation of neurodegeneration. How the PN responds to dissimilar proteotoxic challenges and how these responses are regulated at the organismal level are largely unknown. Here, we report that, while torsin chaperones protect from the toxicity of neurodegeneration-causing polyglutamine stretches, they exacerbate the toxicity of the Alzheimer's disease-causing Aβ peptide in neurons and muscles. These opposing effects are accompanied by differential modulations of gene expression, including that of three neuropeptides that are involved in tailoring the organismal response to dissimilar proteotoxic insults. This mechanism is regulated by insulin/IGF signaling and the transcription factor SKN-1/NRF. Our work delineates a mechanism by which the PN orchestrates differential responses to dissimilar proteotoxic challenges and points at potential targets for therapeutic interventions.

Keywords: Caenorhabditis elegans; SKN-1/NRF; aging; insulin/IGF cascade; neurodegeneration; neuropeptide signaling; proteostasis; proteotoxicity.