Paeonol Attenuates H2O2-Induced NF-κB-Associated Amyloid Precursor Protein Expression

Abstract

Hydrogen peroxide (H₂O₂) has been shown to promote neurodegeneration by inducing the activation of nuclear factor-κB (NF-κB). In this study, NF-κB activation was induced by H₂O₂ in human neuroblastoma SH-SY5Y cells. Whether paeonol, one of the phenolic phytochemicals isolated from the Chinese herb Paeonia suffruticosa Andrews (MC), would attenuate the H₂O₂-induced NF-κB activity was investigated. Western blot results showed that paeonol inhibited the phosphorylation of IκB and the translocation of NF-κB into the nucleus. The ability of paeonol to reduce DNA binding ability and suppress the H₂O₂-induced NF-κB activation was confirmed by an electrophoretic mobility shift assay and a luciferase reporter assay. Using a microarray combined with gene set analysis, we found that the suppression of NF-κB was associated with mature T cell up-regulated genes, the c-jun N-terminal kinase pathway, and two hypoxia-related gene sets, including the hypoxia up-regulated gene set and hypoxia inducible factor 1 targets. Moreover, using network analysis to investigate genes that were altered by H₂O₂ and reversely regulated by paeonol, we found that NF-κB was the primary center of the network and amyloid precursor protein (APP) was the secondary center. Western blotting showed that paeonol inhibited APP at the protein level. In conclusion, our work suggests that paeonol down-regulates H₂O₂-induced NF-κB activity, as well as NF-κB-associated APP expression. Furthermore, the gene expression profile accompanying the suppression of NF-κB by paeonol was identified. The new gene set that can be targeted by paeonol provided a potential use for this drug and a possible pharmacological mechanism for other phenolic compounds that protect against oxidative-related injury.