Fig. 4

GPNMB levels increase in the brain and plasma of Grn^−/− mice with age. a Representative immunoblots of immature and mature (glycosylated) GPNMB in mouse brain lysates of Grn^+/+ and Grn^−/− mice at 3- and 18-months of age. Beta-actin used as loading control. b Levels of GPNMB (ng/mg protein) in mouse brain lysates measured by ELISA. Tissue from Grn^+/+ (white) and Grn^−/− (red) mice at 18-months (n = 4 per group) and 24-months (n = 4 per group), respectively. Data analyzed by two-way ANOVA. c ELISA quantification of mouse brain GPNMB levels (ng/mg of brain protein) in Grn^+/+ (white) and Grn^−/− (red) mice at 3-, 6-, 9- and 12-month ages (n = 8 per group). Values analyzed by two-way ANOVA. d Levels of GPNMB in 19-month old Grn^+/+ (white) and Grn^−/− (red) mouse plasma measured by ELISA. Data (n = 6 for Grn^+/+ and 13 for Grn^−/−) analyzed using an unpaired student t-test. e Representative sections of Grn^+/+, Grn^+/−, and Grn^−/− mouse thalamus at 3-, 12-, and 24-months of age immunostained for GPNMB. f 19-month-old Grn^+/+ and age-matched Grn^−/− mouse brain coronal sections were stained with anti-GPNMB antibody. GPNMB staining shown for multiple brain regions (cortex (I, VII), hippocampus (II, VIII), corpus callosum (III, IX), striatum (IV, X), thalamus (V, XI) and hypothalamus (VI, XII)). Scale bars (1 nm to 100 µm) are labeled in images and quantitative data shown as mean ± SEM, p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001