Gx-50 Inhibits Neuroinflammation via α7 nAChR Activation of the JAK2/STAT3 and PI3K/AKT Pathways

Recent studies have revealed that the alpha 7 nicotinic acetylcholine receptor (alpha 7 nAChR) is a critical link between inflammation and neurodegeneration, which is closely associated with Alzheimer's disease (AD). The JAK2/STAT3 and PI3K/AKT signaling pathways contribute to the neuroprotective and anti-inflammatory effects of alpha 7nAChR. Our previous studies have shown that treatment with gx-50 improves cognitive function and is neuroprotective. Here, we investigated the effect of gx-50 on alpha 7 nAChR and A beta-induced inflammation in microglia. First, the binding affinity of gx-50 to alpha 7 nAChR was examined using the fluorescence-based Octet RED system, and the expression of alpha 7 nAChR was detected using real-time PCR and western blotting. We also investigated downstream events of alpha 7 nAChR activity, including the translocation of p-STAT3 and the phosphorylation of JAK2, STAT3, PI3K, and AKT. Finally, the effect of gx-50 on A beta-induced inflammation via alpha 7 nAChR-mediated signaling pathways was investigated using cytokine assays. The results showed that gx-50 is able to act as a specific ligand to activate alpha 7 nAChR, which then upregulates the JAK2/STAT3 and PI3K/AKT signaling pathways to inhibit the secretions of proinflammatory cytokines, such as IL-1 beta. In conclusion, the results suggest that gx-50 could inhibit the A beta-induced inflammatory response in microglia via alpha 7 nAChR activity, which might be a successful therapeutic target against AD.