Single-cell RNA sequencing uncovers the excitatory/inhibitory synaptic unbalance in the retrosplenial cortex after peripheral nerve injury

Abstract

Nerve injury in the somatosensory pathway may induce maladaptive changes in the transcriptional or protein levels that contribute to the development and maintenance of neuropathic pain. The retrosplenial cortex (RSC) processes nociceptive information, and it presents structural and molecular changes after nerve injury, in contrast, the detailed transcriptional changes in the RSC were unknown. Here we first confirm the involvements of RSC in the regulation of pain sensation and observe that the same peripheral stimulation activated more splenial neurons after nerve injury; decreasing the activities of CamkIIa+ splenial cells relieves peripheral pain hypersensitivity. Using a single-cell RNA-sequencing (scRNA-seq) approach, we identify the cell-type-specific gene expressional changes after nerve injury. By analyzing the expression of ligand-gated ion channels, we observe the decreased Gabar1a but increased Gria1in the CamkIIa+ neurons; consistently, we confirm the unbalanced excitatory/inhibitory synaptic transmissions by using the electrophysiological recording approach. Our data, therefore, provide information of the cell type-dependent transcriptomic changes in the RSC after nerve injury, which would help to understand the mechanisms of mediating neuropathic pain.