Daucosterol protects neurons against oxygen-glucose deprivation/reperfusion-mediated injury by activating IGF1 signaling pathway

We previously reported that daucosterol (a sterolin) up-regulates the expression of insulin-like growth factor I (IGF1)¹ protein in neural stem cells. In this study, we investigated the effects of daucosterol on the survival of cultured cortical neurons after neurons were subjected to oxygen and glucose deprivation and simulated reperfusion (OGD/R)², and determined the corresponding molecular mechanism. The results showed that post-treatment of daucosterol significantly reduced neuronal loss, as well as apoptotic rate and caspase-3 activity, displaying the neuroprotective activity. We also found that daucosterol increased the expression level of IGF1 protein, diminished the down-regulation of p-AKT³ and p-GSK-3β⁴, thus activating the AKT⁵ signal pathway. Additionally, it diminished the down-regulation of the anti-apoptotic proteins Mcl-1⁶ and Bcl-2⁷, and decreased the expression level of the pro-apoptotic protein Bax⁸, thus raising the ratio of Bcl-2/Bax. The neuroprotective effect of daucosterol was inhibited in the presence of picropodophyllin (PPP)⁹, the inhibitor of insulin-like growth factor I receptors (IGF1R)¹⁰. Our study provided information about daucosterol as an efficient and inexpensive neuroprotectants, to which the IGF1-like activity of daucosterol contributes. Daucosterol could be potentially developed as a medicine for ischemic stroke treatment.