ProNGF/NGF Modulates Autophagy and Apoptosis through PI3K/Akt/mTOR and ERK Signaling Pathways following Cerebral Ischemia-Reperfusion in Rats

NGF is involved in the process of autophagy; however, the underlying mechanisms of proNGF/NGF on autophagy in cerebral ischemia-reperfusion (CIR) remain unclear. This study explored the potential pathway of proNGF/NGF in mediating autophagy and apoptosis and thereby contributed to poststroke neurological rehabilitation. In this study, PC12 cell lines and male SD rats were used to simulate CIR; it was found that within 24h reperfusion, proNGF was the predominant form of Ngf while after 24h NGF was produced by proNGF transformation. The mature NGF was found to protect neurons against autophagic and apoptotic damage caused by CIR, but proNGF can cause both autophagic and apoptotic neuronal damage. The protective effect of NGF is associated with the activation of the PI3K/Akt/mTOR and ERK pathway and, as well as the change of autophagy-related proteins. On the other hand, proNGF promoted the ERK pathway increasing autophagy and affected the apoptosis-related proteins in vivo and in vitro. These results were also verified in male SD rats with CIR that neurological deficit caused by CIR can be rescued by recombinant and wild-type NGF, and vice-versa by proNGF.