A Novel Gastrodin Derivative with Neuroprotection Promotes NGF-Mimic Activity by Targeting INSR and ACTN4 to Activate PI3K/Akt Signaling Pathway in PC12 Cells

Gastrodin (gas) has been shown to promote neuroprotection and reverse Alzheimer's disease (AD) pathology. However, its high effective dose limits its potential in treating AD. In this study, a bioassay system using PC12 cells and the nerve growth factor (NGF)-mimic effect was employed to investigate the structure-activity relationship of gas derivatives. Among the synthesized compounds, GAD037 demonstrated the highest NGF-mimic activity, surpassing gas. Additionally, GAD037 exhibited significant neuroprotective effects, reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, thereby improving the survival of PC12 cells under oxidative stress. It also protected cells from A<i>β</i>-induced toxicity. Target protein identification and mechanistic studies revealed that insulin receptor (INSR) and alpha-actinin-4 (ACTN4) are potential targets of GAD037, confirmed through specific inhibitors, small interfering RNA (siRNA) analysis, a cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS). Moreover, the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and rat sarcoma (Ras)/protooncogene serine-threonine protein kinase (Raf)/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways were found to be involved in the NGF-mimic activity of GAD037. In conclusion, GAD037 exhibits superior NGF-mimic and neuroprotective activities compared to gas, suggesting its potential as a lead compound for anti-AD applications.