Glycated Tau Protein in Alzheimer Disease: A Mechanism for Induction of Oxidant Stress

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 91; no. 16; pp. 7787 - 7791
• Main Authors: Yan, S D, Chen, X, Schmidt, A M, Brett, J, Godman, G, Zou, Y S, Scott, C W, Caputo, C, Frappier, T, Smith, M A
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 02-08-1994; National Acad Sciences; National Academy of Sciences
• Subjects: Alzheimer Disease - metabolism; Alzheimer Disease - pathology; Alzheimer's disease; Alzheimers disease; Antibodies; Antigens; Brain - pathology; Enzyme linked immunosorbent assay; Epitopes; Glycation End Products, Advanced - isolation & purification; Glycation End Products, Advanced - metabolism; Humans; Immunohistochemistry; Medical research; Neuroblastoma - metabolism; Neurofibrillary tangles; Neurofibrillary Tangles - ultrastructure; Neurons; Oxygen; Pathology; Proteins; Reactive Oxygen Species - metabolism; Recombinant Proteins - metabolism; tau Proteins - genetics; tau Proteins - isolation & purification; tau Proteins - metabolism; Temporal lobe; Tumor Cells, Cultured
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.91.16.7787

The stability of proteins that constitute the neurofibrillary tangles and senile plaques of Alzheimer disease suggests that they would be ideal substrates for nonenzymatic glycation, a process that occurs over long times, even at normal levels of glucose, ultimately resulting in the formation of advanced glycation end products (AGEs). AGE-modified proteins aggregate, and they generate reactive oxygen intermediates. Using monospecific antibody to AGEs, we have colocalized these AGEs with paired helical filament tau in neurofibrillary tangles in sporadic Alzheimer disease. Such neurons also exhibited evidence of oxidant stress: induction of malondialdehyde epitopes and heme oxygenase 1 antigen. AGE-recombinant tau generated reactive oxygen intermediates and, when introduced into the cytoplasm of SH-SY5Y neuroblastoma cells, induced oxidant stress. We propose that in Alzheimer disease, AGEs in paired helical filament tau can induce oxidant stress, thereby promoting neuronal dysfunction.