This age-dependent shift in Aβ peptide profile coincided with reduced expression of glycosylated species of ADAM-10 (α-secretase) and BACE1 (β-secretase), and an increased co-immunoprecipitation of presenilin-1 with nicastrin (components of the γ-secretase complex).
Focusing on the donor's sex and APOE ε4 status as nominal variables (i.e., omitting diagnosis from the stratification) revealed that increases in Aβ peptides were specific to female carriers of the ε4 allele and correlated with the proportional expression of BACE1/β-secretase and ADAM10/α-secretase in the cortex and with nicastrin (γ-secretase) expression in the hippocampus.
In addition, our data verified that YXQN decreased the cerebral amyloid load by attenuating β-secretase BACE1 and γ-secretase PS1 in the pathological processing of APP, and promoting the level of α-secretase ADAM10 in the physiological processing of APP to generate more sAPPα, which combats amyloidosis formation, and also carries out neurotropic and neuroprotective effect.
Similarly, transgenic ADAM10 endothelial knockout mice displayed lower LRP1 shedding in the brain and significantly enhanced Aβ clearance across the BBB compared to wild-type animals.
Gemfibrozil, an agonist of PPARα, induced the recruitment of PPARα:retinoid x receptor α, but not PPARγ coactivator 1α (PGC1α), to the Adam10 promoter in wild-type mouse hippocampal neurons and shifted APP processing toward the α-secretase, as determined by augmented soluble APPα and decreased Aβ production.
We observed an increase in ADAM10 and a decrease in BACE1 and APP695 protein levels and, subsequently, a reduction in Aβ levels and Aβ burden were present in HupA-treated mouse brain, suggesting that HupA enhances the nonamyloidogenic APP cleavage pathway.