Single-cell RNA sequencing reveals cellular heterogeneity of spinal microglia in neuropathic pain
Recent studies reveal that microglia modulate synaptic transmission by direct synaptic pruning. Microglia reactivation is a crucial mechanism of central sensitization in neuropathic pain, yet the exact changes of microglia during the development of neuropathic pain and its interaction with the spinal inhibitory circuits remains unclear. In this work, single-cell sequencing delineates temporal changes in spinal microglia and identifies a specific type of microglia as the subpopulation mediating synaptic pruning. We found that peripheral nerve injury induced the transition of spinal microglia from a pro-inflammatory to a “pruning” state,  resulting in pain hypersensitivity by spinal disinhibition. Overall design: The ipsilateral SCDH portion at the lumbar (L) 4-L6 levels was incised from sham (PID 0) mice or SNI mice on PID 3, 7, and 14. The tissues collected were then fluorescence activated cell sorting (FACS)-sorted using the monocyte/ macrophage cell surface marker Cd11b. The sorted Cd11b+ cells were processed for single-cell RNA sequencing.