FIGURE 5.
Inhibition of amyloidogenic precursor protein metabolism in CHO/APPWT cells by methylene blue. A, Aβ1–40 and Aβ1–42 species were separately measured in cell supernatants from CHO/APPWT cells by sandwich ELISAs. B, inhibition of amyloidogenic APP processing in CHO/APPWT cells treated with various doses of MB. Western blots using an amino-terminal Aβ1–17 monoclonal antibody (mAb 6E10) or a carboxyl-terminal BACE monoclonal antibody (mAb BACE) show holo-APP, carboxyl-terminal fragment generated by amyloidogenic APP cleavage (C99, β-CTF), and BACE, respectively. β-actin is included as an internal reference control, and densitometry data are shown as ratios of β-actin below each lane. C, densitometry results are shown as ratios of C99 to β-actin at various MB doses. All statistical comparisons are between 0 μm and various doses of MB (*, p < 0.05; **, p < 0.01; ***, p < 0.001), and similar results were observed in 3–4 independent experiments.