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P4–311: PAN–811 protects primary neurons from Aβ neurotoxicity: A potential drug for Alzheimer's disease
Author(s) -
Ghanbari Hossein A.,
Jiang Zhi-Gang
Publication year - 2006
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.2006.05.2052
Subject(s) - neurotoxicity , oxidative stress , pharmacology , antioxidant , chemistry , toxicity , neuroprotection , biochemistry , medicine
the -amyloid (A ) peptide occurs due to aberrant processing of the full-length A precursor protein (APP) by a group of proteases termed secretase. Objective(s): Neurodegeneration is believed to be triggered by the accumulation of potentially toxic A species which are generated following and secretase cleavage of APP. We have reported earlier that memantine reduces the levels of the secreted APP (sAPP), and A peptides in the human neuroblastoma (SK-N-SH) cells and in rat primary cortical neurons. Methods: To understand the mechanism of A reduction by memantine, the activity of and -secretase enzymes was determined in SK-N-SH cells treated with memantine (4 g/ ml for four days) using a fluorescent-based enzyme assay utilizing enzyme-specific substrates and reporter molecules. For the -secretase assay, the APP peptide substrate YEVHHQKLV and EDANS/DABCYL as the reporter system were used. This substrate corresponds to the amino acid sequence associated with -secretase cleavage of APP (681-689). For the -secretase assay, the APP peptide substrate REEVNLDAEFKR corresponding to the amino acid sequence with -secretase cleavage of APP (668-675) was used. We also determined the effects of memantine on the levels of soluble APP and A peptides in the conditioned media by Western immunoblotting and ELISA assays. Results: Our MTT results indicate that there was no cellular loss in memantine-treated cells compared to control, which was corroborated by LDH results showing no cellular toxicity. In our initial experiments, memantine-treated cell extracts showed a reduction in secretase activity without any significant change in -secretase activity. The levels of total sAPP, and A peptides were also reduced in memantinetreated media compared to control. Conclusions: Further experiments are in progress to better understand the mechanism of memantine’s effect on secretases.