Abstract
Inhibiting β-amyloid (Aβ)-induced microglial activation is proposed as an effective strategy for the treatment of Alzheimer's disease. Tetrahydroxystilbene glycoside (TSG) is the main active ingredient of Polygonum multiflorum and has a wide range of biological properties, including antiinflammation. Here, we focused on the function and regulatory mechanism of TSG in Aβ-induced N9 and BV2 cells. The results showed that Aβ treatment induced the activation of microglia cells and the production of inflammatory molecules, including inducible nitric oxide synthase, nitric oxide, cyclooxygenase 2, and prostaglandin E2, which were significantly inhibited by TSG pretreatment. Furthermore, we found Aβ exposure increased the levels of microglial M1 markers, interleukin (IL)-1β, IL-6, and tumor necrosis factor α, and the pretreatment of TSG suppressed the increase of M1 markers and enhanced the levels of M2 markers, including IL-10, brain-derived neurotrophic factor, glial cell-derived neurotrophic factor, and arginase-1. PU.1 overexpression was found to eradicate the anti-inflammatory effects of TSG in Aβ-induced microglial cells. Taken together, these findings indicate that TSG attenuates Aβ-induced microglial activation and polarizes microglia towards M2 phenotype, which may be closely associated with the regulation of PU.1.