Fig. 2

Astroglial and microglial response, as well as ceramide accumulation in Pink1-deficient mouse brain. The immunohistochemical staining of GFAP as astroglial marker and Iba1 as microglial marker in Pink1−/− mouse brain at the age of 18 months demonstrated a mild increase in the frequency of inflammatory glial reactions, best detectable along the corticospinal tract where it traverses the brainstem (a, 10× objective used) and the striatal region (b, 4× objective). c The elevated frequency of this glial response was demonstrated in cell counts for astrogliosis and microgliosis in relation to total cells per area (nuclear counterstain) in 18-month-old brains that underwent automated immunohistochemistry of GFAP1 and Iba1 demonstrated region-specific mild effects. The substantia nigra was less affected than areas that are penetrated by myelinated axons. Data are displayed as bar graphs, illustrating mean values of serial sectioned and randomly picked mouse brain areas. Brain graphs show standard error of the mean (SEM) of technical replicates with at least n = 3 sections per genotype per region. Statistical analysis would be inappropriate, given that the serial sections were from too few inbred animals. d Increased levels of ceramides, glucosyl-ceramides, and lactosyl-ceramides were observed by liquid chromatography tandem mass spectrometry in the olfactory bulb summarized for ages of 9–13 months, 17 months, and 21 months (n = 3 or 4 mice of each age and genotype). The scatter shows individual mice, the line is the mean, and whiskers show the standard deviation. e Log2-transformed total ceramides across brain regions reveal age-dependent differences between genotype, i.e., an increase over time in wildtype mice that contrast with very high levels in younger Pink1 ^−/− mice which remain at this elevated level. Two-way ANOVA differed significantly between genotypes. Asterisks illustrate the significance (multivariate ANOVA, subsequent t test for each lipid, Holm-Šidák adjusted p values, *p < 0.05, **p < 0.01, ***p < 0.001)