Figure 4.

Additive effects dual activation of PPARγ and RXR in primary microglia. Primary microglia were incubated with indicated concentrations of retinoic acid (A; RA) or bexarotene (B; BEX) in the presence of FAM-Aβ (0.5 μm). After 4 h expose to Aβ, intracellular levels of Aβ were determined. RXR agonists enhanced the uptake of Aβ in rat primary microglia in a concentration-dependent manner. The data show the intracellular Aβ uptake as percentage of control (mean ± SEM of n = 3, *p < 0.05, **p < 0.01, one-way ANOVA, Dunnett's multiple comparison test). C–F, Primary microglia was incubated with the combination of pioglitazone (0.3 μm) (C, D; Pio) or DSP-8658 (0.3 μm) (E, F) with the RXR agonists retinoic acid (10 nm) and bexarotene (1 nm) in the presence of FAM-Aβ (0.5 μm). After 4 h expose to Aβ, intracellular levels of Aβ were determined. Coincubation of PPARγ agonists with RXR agonists showed an additive enhancement on Aβ uptake. The data show the intracellular Aβ uptake as percentage of control (means ± SEM of n = 3, *p < 0.05, **p < 0.01 vs control, ^##p < 0.01 vs DSP-8658, pioglitazone, retinoic acid, or bexarotene alone, one-way ANOVA, Tukey's post hoc test).