Fig. 6

CircAPP regulates microglial polarization through miR-1906/CLIC1 axis in vitro.(A ~ F) The effects of miR-1906 knockdown on the expression of Iba-1, TNF-α, Pro- and cleaved IL-1β, CD16, Arg1 and IL-10 regulated by circAPP knockdown in Aβ-treated BV-2 cells were assessed via Western blot assay, n = 4. (G) The effect of miR-1906 knockdown on Aβ phagocytosis of BV-2 cells regulated by circAPP knockdown was assessed using flow cytometer assay, n = 3 ~ 4. (H ~ M) The effects of CLIC1 overexpression on the expression of Iba-1, TNF-α, Pro- and cleaved IL-1β, CD16, Arg1 and IL-10 regulated by circAPP knockdown in Aβ-treated BV-2 cells were assessed using Western blot assay, n = 4. (N) The effect of CLIC1 overexpression on Aβ phagocytosis of BV-2 cells regulated by circAPP knockdown was assessed using flow cytometry assay, n = 4 ~ 5. (O ~ T) The effects of CLIC1 overexpression on the expression of Iba-1, TNF-α, Pro- and cleaved IL-1β, CD16, Arg1 and IL-10 regulated by miR-1906 overexpression in Aβ-treated BV-2 cells were assessed using Western blot assay, n = 4. (U) The effect of CLIC1 overexpression on Aβ phagocytosis of BV-2 cells regulated by miR-1906 overexpression was assessed using flow cytometry assay, n = 3 ~ 4. (V) Schematic representation of proposed mechanism of circAPP in AD microglial polarization, pathology and cognitive function. CircAPP was upregulated in Aβ-treated microglial cells and the hippocampus of APP/PS1 mice. CircAPP knockdown inhibited its interaction with miR-1906 and increased miR-1906 expression, which in turn retarded CLIC1 expression and channel activity, thereby regulating microglial polarization and ameliorating AD pathology and cognitive function. All data in the figure are presented as mean ± SEM. One-way ANOVA was used to assess statistically significant differences. *P < 0.05, **P < 0.01