title: Amyloid-dependent triosephosphate isomerase nitrotyrosination induces glycation and tau fibrillation.
abstract: Alzheimer's disease neuropathology is characterized by neuronal death, amyloid beta-peptide deposits and neurofibrillary tangles composed of paired helical filaments of tau protein. Although crucial for our understanding of the pathogenesis of Alzheimer's disease, the molecular mechanisms linking amyloid beta-peptide and paired helical filaments remain unknown. Here, we show that amyloid beta-peptide-induced nitro-oxidative damage promotes the nitrotyrosination of the glycolytic enzyme triosephosphate isomerase in human neuroblastoma cells. Consequently, nitro-triosephosphate isomerase was found to be present in brain slides from double transgenic mice overexpressing human amyloid precursor protein and presenilin 1, and in Alzheimer's disease patients. Higher levels of nitro-triosephosphate isomerase (P < 0.05) were detected, by Western blot, in immunoprecipitates from hippocampus (9 individuals) and frontal cortex (13 individuals) of Alzheimer's disease patients, compared with healthy subjects (4 and 9 individuals, respectively). Triosephosphate isomerase nitrotyrosination decreases the glycolytic flow. Moreover, during its isomerase activity, it triggers the production of the highly neurotoxic methylglyoxal (n = 4; P < 0.05). The bioinformatics simulation of the nitration of tyrosines 164 and 208, close to the catalytic centre, fits with a reduced isomerase activity. Human embryonic kidney (HEK) cells overexpressing double mutant triosephosphate isomerase (Tyr164 and 208 by Phe164 and 208) showed high methylglyoxal production. This finding correlates with the widespread glycation immunostaining in Alzheimer's disease cortex and hippocampus from double transgenic mice overexpressing amyloid precursor protein and presenilin 1. Furthermore, nitro-triosephosphate isomerase formed large beta-sheet aggregates in vitro and in vivo, as demonstrated by turbidometric analysis and electron microscopy. Transmission electron microscopy (TEM) and atomic force microscopy studies have demonstrated that nitro-triosephosphate isomerase binds tau monomers and induces tau aggregation to form paired helical filaments, the characteristic intracellular hallmark of Alzheimer's disease brains. Our results link oxidative stress, the main etiopathogenic mechanism in sporadic Alzheimer's disease, via the production of peroxynitrite and nitrotyrosination of triosephosphate isomerase, to amyloid beta-peptide-induced toxicity and tau pathology.
authors.affiliation: Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Francesc X
authors.initials: FX
authors.lastname: Guix
authors.forename: Gerard
authors.initials: G
authors.lastname: Ill-Raga
authors.forename: Ramona
authors.initials: R
authors.lastname: Bravo
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakaya
authors.forename: Gianni
authors.initials: G
authors.lastname: de Fabritiis
authors.forename: Mireia
authors.initials: M
authors.lastname: Coma
authors.forename: Gian Pietro
authors.initials: GP
authors.lastname: Miscione
authors.forename: Jordi
authors.initials: J
authors.lastname: Villà-Freixa
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Suzuki
authors.forename: Xavier
authors.initials: X
authors.lastname: Fernàndez-Busquets
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Valverde
authors.forename: Bart
authors.initials: B
authors.lastname: de Strooper
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Muñoz
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D016022:Case-Control Studies; D002460:Cell Line; D045744:Cell Line, Tumor; D005625:Frontal Lobe / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008958:Models, Molecular; D009447:Neuroblastoma; D016874:Neurofibrillary Tangles / Q000378:metabolism; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D014305:Triose-Phosphate Isomerase / Q000032:analysis / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism; D016875:tau Proteins / Q000032:analysis / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D016875:tau Proteins; D030421:Peroxynitrous Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D014305:Triose-Phosphate Isomerase