My research identified an AMPK-independent pathway through which resveratrol reduces β-amyloid levels which may have potential as a viable treatment option for AD.
The leading hypothesis for the cause of Alzheimer’s disease (AD) is chronically high levels of synapse-disrupting β-amyloid peptide fragments in the brain. A study led by Francesca-Fang Liao has shown that metformin, a drug used to treat type 2 diabetes, may exacerbate the progression of AD by increasing the biogenesis of β-amyloid peptides, which are central in AD pathology. Vingtdeux et al. have shown that the natural polyphenol resveratrol reduces β-amyloid levels in vitro through modulation of AMP-activated protein kinase signaling.
Working with Mrs. Donna Leonardi of the Bergen County Academies, I have studied the individual and combinatorial effects of metformin and resveratrol on the accumulation and degradation of β-amyloid peptides. Using biochemical assays such as Enzyme-Linked Immunosorbent Assays (ELISAs), transmission electron microscopy, and fluorescence microscopy, I have been able to better understand the mechanisms of action of metformin and resveratrol in a mouse neuroblastoma cell model, N2a-695, that had been transfected to produce human amyloid precursor protein, which is cleaved by neuronal proteases to form β-amyloid.
Originally, I hypothesized that resveratrol, when delivered in combination with metformin, would reduce the constitutive production of β-amyloid in N2a-695 neuroblastoma cells. The measurement of p62 to quantify autophagy and the activation of AMPK suggested that metformin causes aberrant autophagy, which leads to β-amyloid accumulation. Resveratrol significantly reduced β-amyloid in cells treated with metformin, however via a pathway independent of AMPK or autophagy. Preliminary electron microscopy showed that there was no significantly greater presence of autophagosomes in cells treated with resveratrol compared to untreated cells.
Qualitative observation of mitochondrial superoxide through qualitative fluorescence microscopy revealed that mitochondrial superoxide appeared to be reduced in cells treated with resveratrol and the combinatorial treatment of resveratrol and metformin. Furthermore, quantitative fluorescence assays indicated that resveratrol causes a decrease in superoxide, a reactive oxygen species, suggesting a contribution of mitochondrial integrity in the ability of cells to degrade β-amyloid peptides. The combinatorial treatment of resveratrol and metformin caused the decrease of caspases 3/7 suggesting that the combination of the two compounds has neuroprotective properties. My research identified an AMPK-independent pathway through which resveratrol reduces β-amyloid levels, which may have potential as a viable treatment option for AD.Michelle Guo is a Brevia staff writer and can be reached at firstname.lastname@example.org.
She would like to thank Mrs. Donna Leonardi for her immense support and guidance throughout her high school research experiences. Additionally, she is grateful to the Bergen County Technical Schools’ superintendent Dr. Howard Lerner and the Bergen County Academies principal Mr. Russell Davis for their dedication to the continuation of high school science research exploration. Without them, her development as a scientist would not have been possible.