%0 Journal Article %J J Alzheimers Dis %D 2016 %T Metformin Facilitates Amyloid-β Generation by β- and γ-Secretases via Autophagy Activation. %A Son, Sung Min %A Shin, Hong-Joon %A Byun, Jayoung %A Kook, Sun Young %A Moon, Minho %A Chang, Yu Jin %A Mook-Jung, Inhee %K Alzheimer Disease %K Amyloid beta-Peptides %K Amyloid beta-Protein Precursor %K Amyloid Precursor Protein Secretases %K Animals %K Autophagy %K Cell Line, Tumor %K Disease Models, Animal %K Female %K Humans %K Hypoglycemic Agents %K Lysosomes %K Metformin %K Mice %K Mice, Inbred C57BL %K Mice, Transgenic %K Microscopy, Electron %K Mutation %K Neuroblastoma %K Signal Transduction %X

The evidence of strong pathological associations between type 2 diabetes and Alzheimer's disease (AD) has increased in recent years. Contrary to suggestions that anti-diabetes drugs may have potential for treating AD, we demonstrate here that the insulin sensitizing anti-diabetes drug metformin (Glucophage®) increased the generation of amyloid-β (Aβ), one of the major pathological hallmarks of AD, by promoting β- and γ-secretase-mediated cleavage of amyloid-β protein precursor (AβPP) in SH-SY5Y cells. In addition, we show that metformin caused autophagosome accumulation in Tg6799 AD model mice. Extremely high γ-secretase activity was also detected in autophagic vacuoles, apparently a novel site of Aβ peptide generation. Together, these data suggest that metformin-induced accumulation of autophagosomes resulted in increased γ-secretase activity and Aβ generation. Additional experiments indicated that metformin increased phosphorylation of AMP-activated protein kinase, which activates autophagy by suppressing mammalian target of rapamycin (mTOR). The suppression of mTOR then induces the abnormal accumulation of autophagosomes. We conclude that metformin, an anti-diabetes drug, may exacerbate AD pathogenesis by promoting amyloidogenic AβPP processing in autophagosomes.

%B J Alzheimers Dis %V 51 %P 1197-208 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26967226?dopt=Abstract %R 10.3233/JAD-151200 %0 Journal Article %J J Alzheimers Dis %D 2016 %T An Optimized Combination of Ginger and Peony Root Effectively Inhibits Amyloid-β Accumulation and Amyloid-β-Mediated Pathology in AβPP/PS1 Double-Transgenic Mice. %A Lim, Soonmin %A Choi, Jin Gyu %A Moon, Minho %A Kim, Hyo Geun %A Lee, Wonil %A Bak, Hyoung-Rok %A Sung, Hachang %A Park, Chi Hye %A Kim, Sun Yeou %A Oh, Myung Sook %K Alzheimer Disease %K Amyloid beta-Peptides %K Amyloid beta-Protein Precursor %K Analysis of Variance %K Animals %K Cyclooxygenase 2 %K Disease Models, Animal %K Dose-Response Relationship, Drug %K Ginger %K Glial Fibrillary Acidic Protein %K Humans %K Male %K Mice %K Mice, Transgenic %K Mutation %K Paeonia %K Phytotherapy %K Plant Preparations %K Plaque, Amyloid %K Presenilin-1 %X

The progressive aggregation of amyloid-β protein (Aβ) into senile plaques is a major pathological factor of Alzheimer's disease (AD) and is believed to result in memory impairment. We aimed to investigate the effect of an optimized combination of ginger and peony root (OCGP), a standardized herbal mixture of ginger and peony root, on Aβ accumulation and memory impairment in amyloid-β protein precursor (AβPP)/presenilin 1 (PS1) double-transgenic mice. In an in vitro thioflavin T fluorescence assay, 100 μg/ml OCGP inhibited Aβ accumulation to the same extent as did 10 μM curcumin. Furthermore, AβPP/PS1 double-transgenic mice treated with OCGP (50 or 100 mg/kg/day given orally for 14 weeks) exhibited reduced Aβ plaque accumulation in the hippocampus and lower levels of glial fibrillary acid protein and cyclooxygease-2 expression compared with vehicle-treated controls. These results suggest that OCGP may prevent memory impairment in AD by inhibiting Aβ accumulation and inflammation in the brain.

%B J Alzheimers Dis %V 50 %P 189-200 %8 2016 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/26639976?dopt=Abstract %R 10.3233/JAD-150839