Nociceptive neurons inhibit neutrophil extracellular trap formation via MLKL-licensed histone release

Neutrophil-involved neuroinflammation in dorsal root ganglion (DRG) plays double-sword roles in chronic pain. How DRG neuron-neutrophil interaction contributes to chronic pain remains unclear. Here, we report that MLKL, a key molecule in necroptosis, is constitutively expressed in the nucleus of nociceptive neurons and binds to histone H3. Periphery inflammation disrupted MLKL/H3 interaction, leading to cytoplasmic translocation of MLKL and release of histone H3. Extracellular histone H3 induces neuronal hyperactivity, neutrophil extracellular trap (NET), and hyperalgesia, possibly through P2X7 receptor and Toll-like receptor 4. Nociceptive-specific depletion of Mlkl significantly decreased pain threshold and exacerbated NET formation independent of cell death. Neutralizing extracellular histone, clearing extracellular DNA or restoring nuclear localization of MLKL can reduce both NET formation and hyperalgesia in Mlkl −/− m ice. These data demonstrated that the nociceptive neuron-neutrophil interaction mediated by this MLKL-histone-NET cascade may serve as a potential therapeutic target for chronic inflammatory pain.