Mechanism of JAK/STAT re-activation by BDNF in HSCs. BDNF (100 pM) was administered to treat the human Schwann cell HSCs for 0 min, 10 min, 30 min, 60 min, 120 min, 24 hr, 48 hr, and 72 hr. (A) JAK2 was activated by BDNF treatment and possessed two phosphorylation peaks, which was similar to the response of STAT3/STAT1; (B) the phosphorylation levels of JAK2, STAT1 and STAT3 were presented as a ratio of phosphorylated form to total expressed forms. P1: phosphorylation early peak. P2: phosphorylation late peak. The cell culture mediums from the above treatment were applied to assay the level of cytokines secreted from HSCs by ELISA; (C) 1 hr after the BDNF treatment, HSCs began to secrete OSM-M at levels reaching ~20±0.8 pg/mL at 24 hr (#P>0.05); (D) BDNF significantly increased the secretion of IL6 from HSCs after 1 hr of the treatment and reached ~360.9±74 pg/mL at 72 hr (*P<0.01). Three independent experiments were done for each data point, and the error bars represent ± SD. JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSCs, human Schwann cells; BDNF, brain-derived neurotrophic factor; ELISA, enzyme linked immunosorbent assay.