Figure 1.
Effects of (+)-phenserine on brain amyloid levels in Tg2576 mice.
Levels of tris-soluble (soluble) and guanidine-soluble (insoluble) Aβ1-42 and Aβ1-40 in the cerebral cortices of 4- to 6-month-old (A) and 15- to 18-month-old (B) Tg2576 transgenic mice treated with saline (Sal) or (+)-phenserine (Phe) for 16 days. *P<0.05 and **P<0.01 compared to saline-treated mice (Mann-Whitney test). Values are expressed as means ± SEM throughout the manuscript.
Figure 2.
Modulation of amyloid-β (Aβ) burden in 15- to 18-month-old Tg2576 mice treated with (+)-phenserine.
(A) top Binding of the amyloid ligand 3H-PIB (1.5 nM) to fibrillar Aβ in the brains of 15- to 18-month-old Tg2576 mice treated with saline or (+)-phenserine (Phe). A decrease in 3H-PIB binding was observed following (+)-phenserine treatment compared to saline treated mice (p = 0.05; Mann-Whitney test). Bottom, representative autoradiography distributions of 3H-PIB in sagittal hemibrain sections of saline- and (+)-phenserine-treated Tg2576 mice. (B) Representative sections illustrating immunohistochemical staining of amyloid plaques with antibodies Aβ1-42 and 4G8 in the cerebral cortices of 15- to 18-month-old Tg2576 mice treated with (+)-phenserine and saline.
Figure 3.
Synaptophysin protein levels in the cerebral cortices of 4- to 6- and 15- to 18-month-old wild-type (Wt, white bars) and Tg2576 mice (black bars) after treatment with saline (Sal) or (+)-phenserine (Phe).
The signals corresponding to the synaptophysin levels were normalized to β-actin in each gel, and a pooled sample (P) was used to control the intergel variability. **P<0.01 compared to saline-treated 4- to 6-month-old Tg2576 mice (Mann-Whitney test). Values are expressed as means ± SEM.
Figure 4.
(+)-Phenserine-induced effects on proinflammatory cytokines (IL-1β, TNF-α) and a chemokine (MCP-1) in Tg2576 and wt mice brains.
Effects of (+)-phenserine treatment on IL-1β levels (A), MCP-1 levels (B), and TNF-α levels (C) in the cerebral cortices of 4- to 6- and 15- to 18-month-old wild-type (Wt, white bars) and Tg2576 mice (black bars) treated with saline (Sal) or (+)-phenserine (Phe). *P<0.05 compared to saline-treated 15- to 18-month-old Tg2576 mice (Mann-Whitney test), **p<0.01 compared to saline-treated 4- to 6-month-old wildtype and Tg2576 mice (Mann-Whitney test). Values are expressed as means ±SEM.
Figure 5.
The effects of (+)-phenserine treatment on cell proliferation in the hippocampi of Tg2576 mice.
The number of bromodeoxyuridine-positive (BrdU+) cells was increased in hippocampal regions of 4- to 6-month-old Tg2576 mice treated with saline (Sal) or (+)-phenserine (Phe). The number of BrdU+ cells was counted in the dentate gyrus (DG) (A), and in the CA1 region (B) in the hippocampi of wild-type (Wt) and Tg2576 mice. Representative images of the DG and CA1 in Tg2576 mice treated with saline (Sal) or (+)-phenserine (Phe) are shown in (C). The number of BrdU+ cells in the DG of 15- to 18-month-old Wt and Tg2576 mice treated with saline or (+)-phenserine is shown in Figures (D) and (E). *P<0.05 compared to saline-treated Tg2576 mice aged 4–6 or 15–18 months (unpaired t-test). Values are expressed as means ± SEM. Sections were immunolabeled with BrdU (red) and the nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI, blue) and visualized at 20X magnification.
Figure 6.
Increased dendritic arborization of newborn neurons in the dentate gyrus (DG) following treatment with (+)-phenserine.
The number of doublecortin (DCX)-positive cells in the DG of 4- to 6- and 15- to 18-month-old mice after saline (Sal) or (+)-phenserine (Phe) treatedment (A), and the number of DCX+ cells with dendrites in 4- to 6-month-old mice (B). Illustrative images (20X magnification) of DCX immunoreactivity in 4- to 6-month-old Tg2576 mice that had been given saline or (+)-phenserine, and a 40X magnification of DCX+ cells with (black arrow) and without (white arrow) dendrites (C). Illustrative images (20X magnification) of DCX immunoreactivity in 15- to 18-month-old saline-treated and (+)-phenserine-treated Tg2576 mice (D). *P<0.05 compared to saline-treated 4- to 6-month-old Tg2576 mice, **p<0.01 compared to 4- to 6-month-old mice (Mann-Whitney test). Values are expressed as means ±SEM.
Figure 7.
Correlations of amyloid-β (Aβ) levels with synaptophysin levels, cell proliferation and proinflammatory markers in the brains of 4- to 6- and 15- to 18-month-old Tg2576 mice.
Correlation of synaptophysin levels with cortical guanidine-soluble (insoluble) Aβ1-42 levels (A) and tris-soluble (soluble) Aβ1-42 levels (B). Correlation of insoluble Aβ1-42 levels with the number of bromodeoxyuridine-positive (BrdU+) cells (C) in the dentate gyri of 4- to 6-month-old Tg2576 mice. In Tg2576 mice aged 15–18 months, the relationships between MCP-1 levels and insoluble and soluble Aβ1-42 levels in the cortex are shown in (D) and (E), respectively, and the relationship between the number of proliferating BrdU+ cells in the dentate gyrus and cortical soluble Aβ1-42 levels is shown in (F) (Spearman rank test). Open circles indicate saline-treated animals (n = 5–7) and closed circles indicate (+)-phenserine-treated animals (n = 5–8).