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P3‐378: Misfolded superoxide dismutase 1 (SOD1) as a novel target for Alzheimer's disease
Author(s) -
Grad Leslie I.,
Donkin James,
O'Neill Megan A.,
Wang Jing,
Scrocchi Louise A.,
Wellington Cheryl L.,
Cashman Neil R.
Publication year - 2010
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2010.05.1920
Subject(s) - sod1 , epitope , amyotrophic lateral sclerosis , amyloid (mycology) , superoxide dismutase , microbiology and biotechnology , alzheimer's disease , chemistry , biology , neuroscience , antibody , immunology , medicine , disease , pathology , biochemistry , oxidative stress
can cause elevations in extracellular levels of Ab in vivo, while chronic dosing can reduces synuclein deposition in a mouse model of synucleinopathy, together suggesting that the drug may enhance clearance of protein aggregates. Autophagy is one pathway, considered to be important in removal of aggregated or misfolded proteins in a number of neurodegenerative diseases. In this study, we investigated whether latrepirdine can induce autophagy and whether this is associated with enhanced degradation of Ab42. Our experimental model was the yeast Saccharomyces cerevisiae, due to its well-characterized autophagic machinery, its ease of genetic manipulation, and the relative abundance of good biochemical assays for autophagic activity in yeast. Methods: Autophagy was assessed via the use of a vacuolar membrane specific lipophilic dye, FM 4-64, to follow bulk transport of cytosolic components to the vacuole for degradation. The ability of laterpirdine to induce autophagy was compared to that of cell nitrogen deprivation and rapamycin treatment, which are known autophagy activators. To selectively determine the effect of latrepirdine on intracellular Ab degradation, a GFP (green fluorescent protein)-Ab42 fusion construct was constitutively expressed in yeast. Cells expressing GFP-Ab42 were grown until exponential phase before treatment with either vehicle or latrepirdine, following which the number of GFP fluorescent cells were quantified Results: Latrepirdine (1uM) was shown to induce bulk internalization of FM4-64 stain into vacuoles, suggesting that autophagy was activated. Latrepirdine induced autophagy in w30% of cells as compared to w5% in untreated cells and w90% in 0.2 uM rapamycin-treated cells. Latrepirdine was also found to significantly reduce the number of GFP-Ab fluorescing cells, indicating enhanced clearance or degradation of intracellular GFP-Ab Conclusions: Latrepirdine was found to activate autophagy in yeast, and this, in turn, was associated with increased degradation of intracellular GFP-Ab. Current work is in progress to understand the specific nature and pathway(s) of latrepirdine-induced autophagy and degradation of intracellular Ab.