Figure 3.

A schematic diagram for the cysteine-cysteine chemokine ligand 21 (CCL21) axonal transport and its role in neuron-microglia signaling following spinal cord injury (SCI). (A) CCL21 in damaged neurons is sorted into vesicles that are transported via axons and reach presynaptic structures and secreted into parenchyma. (B) Distal release of CCL21 triggers microglial activation at distant site from the lesion, which release proinflammatory cytokines and microparticles reinforcing neuronal damage. The latter causes more distant CCL21 release through their axonal transport.