Effects Of GX-50 On Amyliod-Induced Inflammation In Primary Cultured Microglia Cells

Microglia, the resident cell in the central nervous, can be activated byβ-amyloid protein (Aβ), the major component of senile plaques in Altheimer's disease(AD). Activated microglia cells not only eliminate Aβor Aβ-receptor complex, but also release inflammatory factors, which play a critical role in AD pathology. Recent reports strongly suggest that regulating microglia function could be a potential therapeutic approach to AD.Object:GX-50, an ingredient from Zanthoxylum, has been suggested to effectively active alpha7 neuronal nicotinic acetylcholine receptor by structure-based drug design methods. Our previous studies showed that alpha7 neuronal nicotinic acetylcholine receptor was involved in the neuroprotective effect of GX-50 on beta-amyloid (Aβ)25-35-induced neuronal damage in primary cultured cortical neurons. And GX-50 could bind to alpha7 neuronal nicotinic acetylcholine receptor of cortical neurons and it inhibited LPS-induced cytokine release of Ana-1 cells. In this study, we investigated the effects of GX-50 on Aβ-induced inflammation in primary cultured microglia cells. Methods:Microglia cells were treated with different concentrations of GX-50 or Aβ, the viability was measured by MTT assay and leakage rate of lactale dehydrogense. The competitive binding assay was performed to verify GX-50 as an agonist ofα7 nAChR. The selected dose (10-6M) of GX-50 was higher than for nicotine based on their lower apparent affinities for high affinity nicotine receptor. After 10-6M GX-50 treatment, Microglia cells were challenged with 25μM Aβ, at the presence or absence of BTX. The supernatant was collected and measured by ELISA and Cytokine Antibody Array.Results:Microglia cells were treated by different concentrations of GX-50 or Aβ, MTT assay and leakage rate of lactale dehydrogense showed that the cell viability had no remarkable change. Pretreatment of the cells with 10-6 M GX-50 for 2 h prior to 2.5×10^-5 M Aβ25-35 exposure caused significant inhibition of TNF-α,IL-1βrelease induced by Aβin microglia cells. Furthermore, GX-50 could bind toα7 nAChR of microglia cells.Conclusion:Our research revealed that GX-50, could inhibit cytokine release induced by Aβin microglia cells. However, further researches should be done to verify the mechanisms.