SARM1 senses dsDNA to promote NAD+ degradation and cell death

Abstract

Detection of DNA is a fundamental strategy for life to recognize non-self or abnormal-self to subsequently trigger the downstream responses. However, the mechanism underlying DNA sensing is incompletely understood. Here, we show that a key neural executioner, sterile alpha and Toll/interleukin-1 receptor (TIR) motif containing 1 (SARM1), senses double-stranded DNA (dsDNA) to promote cell death. dsDNA-bound and -activated SARM1 to degrade nicotinamide adenine dinucleotide (NAD⁺) in a sequence-independent manner. SARM1 bound dsDNA via the TIR domain, and lysine residues in the TIR domain contributed to dsDNA binding. In the cellular context, cytosolic dsDNA from dsDNA transfection or chemotherapy treatment was colocalized with SARM1 and activated SARM1 to elicit NAD⁺ degradation and cell death, which was abrogated by SARM1 knockout or DNA-binding residue mutation. Consistently, SARM1 knockout blocked chemotherapy-induced neuropathy (CIN) in mice. Our results reveal SARM1 as a DNA sensor, which might be targetable for therapeutic interventions.

Keywords: CIN; DNA sensor; NAD; SARM1; TIR domain; axon degeneration; cancer; cell death; chemotherapy-induced neuropathy; metabolism.