Neuronal accumulation of peroxidated lipids promotes demyelination and neurodegeneration though the activation of the microglial NLRP3 inflammasome

Peroxidated lipids accumulate in the presence of reactive oxygen species and are linked to neurodegenerative diseases. Here we found that neuronal ablation of Arf1, a small GTPase important for lipid homeostasis, promoted the accumulation of peroxidated lipids, lipid droplets and ATP in the mouse brain and led to neuroinflammation, demyelination, and neurodegeneration, mainly in the spinal cord and hindbrain. Ablation of Arf1 in cultured primary neurons led to an increase in peroxidated lipids in co-cultured microglia, the activation of the microglial NLRP3 inflammasome, and the release of inflammatory cytokines in an APOE-dependent manner. Deleting the Nlrp3 gene rescued the neurodegenerative phenotypes in the neuronal Arf1-ablated mice. We also observed a reduction in Arf1 in human brain tissue from amyotrophic lateral sclerosis and multiple sclerosis patients. Together, our results uncover a previously unrecognized role of peroxidated lipids released from damaged neurons in the activation of a neurotoxic microglial NLRP3 pathway that may play a role in human neurodegeneration. Study of Arf1 function in the neurons