Fig. 7: Spi1-knockdown reduces microglial response to plaques and Aβ uptake, whereas Spi1-overexpression increases them.
Representative images of colocalization between IBA1-positive microglia and X-34-positive fibrillar plaque in brain slices from Spi1+/+;APP/PS1 and Spi1+/−;APP/PS1 mice (a) or from Spi1+/+;5XFAD and Spi1Tg/0;5XFAD mice (c). Scale bars, 20 μm. b, d Quantification of the IBA1-positive cell coverage area on the fibrillar plaque. Within each box, horizontal lines denote median values; boxes extend from the 25th to the 75th percentile of each group’s distribution of values. The whiskers are shown from min to max, showing all points. ****p < 0.0001 (unpaired, two-tailed t-test). For a and b, WT, n = 13 (n = 8 males, n = 5 females) for Spi1+/+;APP/PS1; KD, n = 15 (n = 9 males, n = 6 females) for Spi1+/−;APP/PS1. For c-d, WT, n = 9 females for Spi1+/+;5XFAD; TG, n = 10 females for Spi1Tg/0; 5XFAD). e, f BV-2 microglial cells were transfected with a Spi1 siRNA or Spi1 plasmid to knockdown or overexpression of Spi1, respectively. Twenty-four hours post-transfection, cells were incubated with 100 nM of Aβ1-42 conjugated with pHrodo Red dye for 48 h. Time-lapse of Aβ uptake level of Spi1-knockdown (e) or -overexpression (f) was compared to each negative control (scrambled siRNA or Empty vector, respectively) under Aβ treatment. The Aβ uptake level in the cells was evaluated using the relative fluorescence unit (RFU) of pHrodo Red emission. All values are mean ± SD. *p < 0.05, **p < 0.01, and ****p < 0.0001 (two-way ANOVA, Sidak’s multiple comparisons test; n = 5 per group). Source data are provided as a Source data file.
