Activating transcription factor 3 promotes spinal cord regeneration of adult zebrafish

Zebrafish is an excellent model to study the mechanisms underlying successful central nervous system (CNS) regeneration. Previous study shows that activating transcription factor 3 (ATF3) promotes neurite outgrowth and is involved in optic nerve regeneration in zebrafish. Here, we used zebrafish model to investigate the role of ATF3 in regeneration following spinal cord injury (SCI). Quantitative polymerase chain reaction (qPCR) and in situ hybridization revealed that ATF3 mRNA levels increased at 12 h and 6 d following SCI. Double labeled immunofluorescence showed that ATF3 expressed in motoneurons. Treatment of anti-sense ATF3 morpholino (MO) inhibited locomotor recovery and decreased axon regeneration of spinal cord injured zebrafish. Further, inhibition of ATF3 up-regulated the expression of inflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). These data suggest that ATF3 could promote locomotor recovery and axon regrowth in zebrafish SCI model possibly by regulating inflammatory response.