Targeted Inhibition of STAT3 in Neural Stem Cells Promotes Neuronal Differentiation and Functional Recovery in Rats with Spinal Cord Injury

Abstract

BackgroundSignal transducer and activator of transcription protein 3 (STAT3) is expressed in neural stem cells (NSCs), and some studies have shown that STAT3 is involved in regulating NSC differentiation. However, the possible molecular mechanism and the role of STAT3 in spinal cord injury (SCI) are unknown. Thus, in the present study, we identified possible molecular mechanisms by which STAT3 regulates NSC differentiation in vitro and investigated the potential therapeutic effect of transplanting STAT3-silenced NSCs in rat SCI models in vivo.MethodsIn vitro, NSCs were divided into the following three groups: control, control shRNA, and STAT3-shRNA lentivirus groups. NSCs in each treatment group were examined for neuronal differentiation via immunofluorescence, and Western blot analysis was used to investigate the possible molecular mechanisms. In vivo, the rats were divided into four groups that underwent laminectomy and complete spinal cord transection accompanied by transplantation of control-shRNA-treated or STAT3-shRNA-treated NSCs at the injured site. Spinal cord-evoked potentials and the Basso-Beattie-Bresnahan score were used to examine functional recovery after SCI. Axonal regeneration and tissue repair were assessed via retrograde tracing using Fluorogold, hematoxylin-eosin staining and immunofluorescence.ResultsKnockdown of STAT3 promoted neuronal differentiation in NSCs and mechanistic target of mammal rapamycin (mTOR) activation in vitro, and transplantation of STAT3-RNAi-treated NSCs enhanced rat functional recovery and tissue repair, as well as neuronal differentiation of the transplanted NSCs in vivo.ConclusionsWe have provided in vitro and in vivo evidence that STAT3 is a negative regulator of NSC neuronal differentiation. Transplantation of STAT3-inhibited NSCs appears to be a promising potential strategy for enhancing the benefit of NSC-mediated regenerative cell therapy for SCI.