Metabolic tuning facilitates nociceptor resilience to excitotoxicity

The capsaicin receptor, TRPV1, mediates the detection of harmful chemical and thermal stimuli. Overactivation of TRPV1 can lead to cellular damage or death through excitotoxicity, a phenomenon associated with painful neuropathy and the paradoxical use of capsaicin as an analgesic. We exploited capsaicin-evoked death to conduct a systematic analysis of excitotoxicity through a genome-wide CRISPRi screen, thereby revealing a comprehensive network of regulatory pathways. We show that decreased expression of mitochondrial electron transport chain (ETC) components protects against capsaicin-induced toxicity by mitigating calcium imbalance and mitochondrial reactive oxygen species production via distinct pathways. Interestingly, TRPV1+ sensory neurons in adult mice maintain lower expression of ETC components and can better tolerate excitotoxicity and oxidative stress compared to other sensory neuron subtypes. We further confirm the regulatory roles of the ETC in sensory neurons through gain-of-function and loss-of-function experiments. These findings implicate ETC tuning as a cellular protective strategy against sensory excitotoxicity.