The Suppressive Effects Of Gx-50on Aβ-induced Chemotactic Migration Of Microglia

Microglia, play a vital role in the development of AD. Once microglia areactivated, they migrate to neuritic plaques and persistently releasepro-inflammatory mediators that lead to neuroinflammation and neuronaldegeneration, accelerating the progression of AD. In this study, weanalyzed whether an AD candidate drug, N-[2-(3,4-dimethoxyphenyl)ethyl]-3-phenyl-acrylamide (gx-50), a compound extracted from Sichuanpeppers (Zanthoxylum bungeanum), exhibited suppressive effects on thechemotactic migration of microglia induced by Aβ. At first, the effects ofgx-50on the migration of primary cultured microglia to Aβ were detectedby transwell assay, and the secretion of chemokine CCL5was measuredby ELISA assay. Then, the release of TGF-β1was detected by ELISAandquantitative real-time PCR, and the activation of the TGF-β1-Smad2pathway was analyzed by western blotting. The LDH assay revealed thatcell viability was not affected by gx-50at concentrations from0.01to100μM; thus, combined with our previous studies,1μM was chosen asthe treatment concentration. The cell transwell measurement demonstrated that gx-50suppressed the chemotactic migration ofmicroglia by nearly50%and inhibited the increase in CCL5triggered byAβ. Moreover, the analysis of the TGF-β1-Smad2pathway revealed thatgx-50can antagonize Aβ-induced down-regulation of TGF-β1at both themRNA and protein levels and stimulate the signal pathway activation.Simultaneously, gx-50pretreatment also significantly enhanced thephosphorylation of glycogen synthase kinase-3β (GSK-3β), whichcorrelated closely with the migration of microglia. In conclusion, in theappearance of Aβ, gx-50pretreatment inhibited the excessive chemotacticmigration of microglia.