ASK1 phosphorylation regulates astrocytic reactive gliosis in vitro and in vivo

Apoptosis signal-regulating kinase 1 (ASK1) may play a pivotal role in reactive gliosis. To assess the role of ASK1 in trauma-induced reactive gliosis, we examined the phosphorylation of ASK1 and the expression of glial fibrillary acidic protein (GFAP) and vimentin after scratch injury in cultured astrocytes and spinal cord injury (SCI) in rats. Enhanced phosphorylation of ASK1 was detected during reactive gliosis both in vitro and in vivo, and P38 MAPK relayed the signal from phosphorylated ASK1 to the activation of astrocytes. Immunoprecipitation analyses suggested that 14-3-3 was dissociated from ASK1 during astrocyte activation. Finally, treatment with thioredoxin reduced ASK1 phosphorylation and reactive gliosis and promoted hindlimb locomotion recovery in SCI rats. These results indicated that ASK1 may play an important role in mechanical-injury-induced reactive gliosis.