James A Duce

Learn More
Alzheimer's Disease (AD) is complicated by pro-oxidant intraneuronal Fe(2+) elevation as well as extracellular Zn(2+) accumulation within amyloid plaque. We found that the AD β-amyloid protein precursor (APP) possesses ferroxidase activity mediated by a conserved H-ferritin-like active site, which is inhibited specifically by Zn(2+). Like ceruloplasmin, APP(More)
The microtubule-associated protein tau has risk alleles for both Alzheimer's disease and Parkinson's disease and mutations that cause brain degenerative diseases termed tauopathies. Aggregated tau forms neurofibrillary tangles in these pathologies, but little is certain about the function of tau or its mode of involvement in pathogenesis. Neuronal iron(More)
Conventional studies of brain changes in normal aging have concentrated on gray matter as the locus for cognitive dysfunction. However, there is accumulating evidence from studies of normal aging in the rhesus monkey that changes in white matter may be a more critical factor in cognitive decline. Such changes include ultrastructural and biochemical evidence(More)
In studies of Alzheimer's disease pathogenesis there is an increasing focus on mechanisms of intracellular amyloid-beta (Abeta) generation and toxicity. Here we investigated the inhibitory potential of the 42 amino acid Abeta peptide (Abeta1-42) on activity of electron transport chain enzyme complexes in human mitochondria. We found that synthetic Abeta1-42(More)
The biggest risk factor for Alzheimer's disease is the process of ageing, but the mechanisms that lead to the manifestation of the disease remain to be elucidated. Why age triggers the disease is unclear but an emerging theme is the inability for a cell to efficiently maintain many key processes such as energy production, repair, and regenerative(More)
Oxidative stress is implicated in Alzheimer disease (AD) pathogenesis, for which evidence indicates that radical species are generated by the redox-active biometal Cu. The contribution of labile Cu to the oxidative stress observed in AD has not been evaluated. The Cu content of postmortem cortical tissue from nondemented elderly controls and AD cases was(More)
By altering key amino acid residues of the Alzheimer's disease-associated amyloid-beta peptide, we investigated the mechanism through which amyloid-beta inhibits cytochrome c oxidase (EC 1.9.3.1). Native amyloid-beta inhibited cytochrome oxidase by up to 65%, and the level of inhibition was determined by the period of amyloid-beta ageing before the(More)
Ceruloplasmin is an iron-export ferroxidase that is abundant in plasma and also expressed in glia. We found a ∼80% loss of ceruloplasmin ferroxidase activity in the substantia nigra of idiopathic Parkinson disease (PD) cases, which could contribute to the pro-oxidant iron accumulation that characterizes the pathology. Consistent with a role for(More)
The equilibrium of metal ions is critical for many physiological functions, particularly in the central nervous system, where metals are essential for development and maintenance of enzymatic activities, mitochondrial function, myelination, neurotransmission as well as learning and memory. Due to their importance, cells have evolved complex machinery for(More)
Mutations in Cu,Zn-superoxide dismutase (SOD1) cause familial amyotrophic lateral sclerosis (ALS). It has been proposed that neuronal cell death might occur due to inappropriately increased Cu interaction with mutant SOD1. Using Cu immobilized metal-affinity chromatography (IMAC), we showed that mutant SOD1 (A4V, G85R, and G93A) expressed in transfected(More)