Figure 1. Astrocytes upregulate SFRP1 expression upon LPS stimulation.

• A–D
  Confocal image analysis of cryostat sections from adult CX₃CR1 ^{+/ GFP} ; Sfrp1 ^{+/ βgal} (A, B); Sfrp1 ^{+/ βgal} (C) and CX₃CR1 ^{+/ GFP} ;Sfrp1 ^−/− (D) and mouse brains three days after intracortical infusion of saline or LPS. Sections were immunostained for βgal (magenta, green in C) and Iba1 (green in A; red in C) or Sfrp1 (magenta) and GFP (green, B and D), and GFAP (cyan in A, B, D, red in C). Arrowheads indicate βgal/GFAP (A) and Sfrp1/GFP co‐localization (B). No Sfrp1 protein is detected in the null mice independently of the treatment (two bottom lines). Scale bar: 25 μm.
• E
  ELISA determination of Sfrp1 levels in brain extracts from 3‐month‐old wt and Sfrp1 ^−/− mice. WT mice were injected either with saline or with LPS. Three days after injection, the region around the injected side (10 mm³ cortical cube) was isolated and SFRP1 content compared with that present in similar region of non‐injected or Sfrp1 ^−/− mice used as negative control (n = 5 mice for each group). Error bars represent standard error. Statistical significance: ns P > 0.5 ****P < 0.0001; one‐way ANOVA followed by the Bonferroni multiple comparisons test.