Figure 1.
Chemical structure of piericidin A.
Figure 2.
Effects of piericidin A treatment on neuronal cell count and synaptic density.
A: Neuronal nuclei (NeuN)-stained sections of the frontal cortex (Cx) of wild-type and P301S+/+ mice treated with vehicle or piericidin A (left panel). Quantification of NeuN immunoreactive cells in the cortex showed no difference in the four animal groups (right panel). Scale bar 50 µm. B: Sections of the frontal cortex stained with an antibody against synaptophysin as marker for the synaptic density (left panel). The immunoreactivity quantified by optical density measurement was significantly reduced in piericidin A treated P301S+/+ mice compared to vehicle treated P301S+/+ (right panel). Scale bar: 10 µm. ## p <0.01, piericidin A treatment vs vehicle treatment at the same genotype. Two-way ANOVA with Fisher LSD post-hoc test.
Figure 3.
Histological sections showing the effect of piericidin A treatment on tau pathology.
Frontal cortex (Cx) of wild-type and P301S+/+ mice treated with vehicle or piericidin A. Sections were stained separately with the antibodies AD2 (A), AT 180 (B), AT8 (C), and AT100 (D). The inserts are 2.5-times magnified compared to the overview images. P301S+/+ mice had significant higher numbers of phospho-tau positive cells in the frontal cortex compared to wild-type animals with the same treatment (lower panels, filled bars). Treatment with piericidin A further increased the number of AD2 immunoreactive cells (A, lower panel) and AT180 immunoreactive cells (B, lower panel). With AT8 immunoreactivity there was the same tendency, however, the difference was not significant (C, lower panel). With the AT100 antibody we only observed immunoreactive cells in piericidin A treated P301S+/+ mice (D). Scale bars: 20 µm. * p<0.05, ** p<0.01, *** p<0.001, P301S+/+ vs. wild-type at the same treatment. # p<0.05, ## p<0.01, ### p<0.001, piericidin A treatment vs. vehicle treatment at the same genotype. Two-way ANOVA with Fisher LSD post-hoc test.
Figure 4.
Western blots showing the effect of piericidin A treatment on total tau and phospho-tau levels.
Upper panels: Western blots of wild-type and P301S+/+ mice, exposed to Piericidin A or vehicle over a period of 28 days, stained with an antibody specific for human tau (HT7, A), an antibody against pSer396/Ser404 (AD2) phosphorylated tau (B), an antibody against pSer202/Thr205 (AT8) phosphorylated tau, an antibody against pThr231 (AT180) phosphorylated tau (C), and an antibody against pThr212/Ser214 (AT100) phosphorylated tau (E). Below the tau Western blots the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) loading control is shown. Lower panels: Quantification of the Western blots after normalization to loading control (GAPDH). In the HT7 and AD2 Western blots, the whole visible band was quantified, whereas in AT180, AT8 and AT100 the 68 kDa band was quantified. # p<0.05, ## p<0.01, ### p<0.001, n.s. not significant, piericidin A treatment vs. vehicle treatment at the same genotype. Two-way ANOVA with Fisher LSD post-hoc test.