CCL28 promotes locomotor recovery after spinal cord injury via recruiting regulatory T cells

BACKGROUND: Chemokines play a key role in post-traumatic inflammation and secondary injury after spinal cord injury (SCI). CCL28, the chemokine CC-chemokine ligand 28, is involved in the epithelial and mucosal immunity. However, whether CCL28 participates in the physiopathologic processes after SCI remains unclear. RESULTS: regulatory T (Treg) cells that express CCR10, a receptor of CCL28, are enriched in the spinal cord after SCI. We further demonstrate that the spinal cord recruits Treg cells through CCL28-CCR10 axis, which in turn function to suppress immune response and promote locomotor recovery after SCI. In contrast, neutralizing CCL28 or CCR10 reduces Treg cell recruitment and delays locomotor recovery. METHODS: transwell migration assay. The mouse locomotor activity was assessed via the Basso Mouse Scale (BMS) system. CONCLUSIONS: These results indicate that NF-κB pathway-regulated CCL28 production plays a protective role after SCI through recruiting CCR10-expressing and immunosuppressive Treg cells, and suggest that interfering CCL28-CCR10 axis might be of potential clinical benefit in improving SCI recovery.