Role of BACE1 in morphine-mediated astrocytic amyloidosis. Representative western blots showing the expressions of (A) BACE1 and HIF-1α (B) Aβ mOC64 and GFAP in HPA transfected with either BACE1 siRNA or scrambled siRNA in the presence or absence of morphine (500 nM). (C) qPCR showing expression of BACE1, HIF-1α, IL1-β, and IL1-6 mRNA in HPAs transfected with either BACE1 or scrambled siRNA. (D) HIF-1α binding motif on the BACE1 promoter. Data are presented as mean±SEM. One-way ANOVA followed by Bonferroni post hoc test was performed, $P< 0.001, *P < 0.05 versus control, #P< 0.001, @P< 0.05 versus scrambled siRNA+ Morphine. Abbreviations: Aβ, amyloid beta, HIF-1α, hypoxia-inducible factor 1α, HPA, human primary astrocyte, IL, interleukin, siRNA, small interfering RNA.