P2‐185: CHARACTERIZING NEUROINFLAMMATORY RESPONSES IN APOLIPOPROTEIN E GENOTYPES

Alzheimer’s disease in a human microglial cells. Methods: Amyloid-beta1-42 was purchased from Thermo Fisher in a lyophilized form. Amyloid-beta was dissolved in HFIP and prepared into an AB42 film. The filmwas re-dissolved in CH3CN/NaCO3 after which samples were incubated for various time points, establishing various fragmentations of AB42. The size of the prepared amyloid beta samples were measured using transmission electron microscopy. To examine the expression profiling of pro-inflammatory, anti-inflammatory, and autophagy genes, human microglia cells (HMC3, ATCC) were incubated with 100 nM Amyloid-beta1-42 of varying fragment sizes for 1 hour at 30 C and then lysed for qPCR analysis. Results: The AB42 fragments spanned from single monomeric fragments to large 4 um fibrils. Treatment of timedependent AB42 fragments to the microglial cells promoted the expression of pro-inflammatory genes in microglia, which linearly increased concurrent with aggregation growth. The expression of pro-inflammatory genes were significantly increased in response to monomeric amyloid-beta, gene expression was further increased with increasing fragment size. In contrast, the expression of anti-inflammatory genes were significantly suppressed, displaying a parabolic nature among gene expression with increasing size of fragment. The expression of autophagy genes has shown a linear decrease in gene expression as fragmentation increased. Conclusions: Amyloid-beta oligomerization has a detrimental role in the activation of microglia and related inflammatory and autophagy genes. Our results illustrate the role of amyloid-beta oligomerization as a causative agent of neuroinflammation by eliciting the polarization of microglial cells towards pro-inflammatory phenotype while attenuating the expression of anti-inflammatory and autophagy genes. Futurework will be to utilize therapeutics to disaggregate amyloid-beta fragments to alleviate inflammation and promote amyloid-beta clearance.