Neurodegenerative proteinopathies are characterized by the intracellular formation of insoluble and toxic protein aggregates in the brain that are closely linked to disease progression. In Alzheimer's disease and in rare tauopathies, aggregation of the microtubule-associated tau protein leads to the formation of neurofibrillary tangles (NFT). In Parkinson's disease (PD) and other α-synucleinopathies, intracellular Lewy bodies containing aggregates of α-synuclein constitute the pathological hallmark.
View Article and Find Full Text PDFThe molecular mechanisms governing γ-secretase cleavage specificity are not fully understood. Herein, we demonstrate that extending the transmembrane domain of the amyloid precursor protein-derived C99 substrate in proximity to the cytosolic face strongly influences γ-secretase cleavage specificity. Sequential insertion of leucines or replacement of membrane-anchoring lysines by leucines elevated the production of Aβ42, whilst lowering production of Aβ40.
View Article and Find Full Text PDFβ-Site amyloid precursor protein cleaving enzyme-1 (BACE-1) is a transmembrane aspartic protease that mediates the initial cleavage of the amyloid precursor protein (APP), leading to the generation of amyloid-β (Aβ) peptides that are thought to be causative of Alzheimer's disease (AD). Consequently, inhibition of BACE-1 is an attractive therapeutic approach for the treatment of AD. In general, in vitro biochemical assays to monitor BACE-1 activity have used the extracellular domain of the protein that contains the catalytic active site.
View Article and Find Full Text PDFAn important event in the pathogenesis of Alzheimer's disease (AD) is the deposition of the amyloid beta (Abeta)1-40 and 1-42 peptides in a fibrillar form, with Abeta42 typically having a greater propensity to undergo this conformational change. A major risk factor for late-onset AD is the inheritance of the apolipoprotein E (apoE) 4 allele [3,14,31]. We previously proposed that apoE may function as a "pathological chaperone" in the pathogenesis of AD (i.
View Article and Find Full Text PDFGenetic, neuropathological, and biochemical studies have provided strong evidence for a central role of amyloid in the pathogenesis of Alzheimer's disease (AD). We have proposed previously that peptides designed as beta-sheet breakers may be useful in preventing the formation of amyloid plaques. In this study, we describe a modified beta-sheet breaker peptide with improved pharmacological properties, a high rate of penetration across the blood-brain barrier, and the ability to induce a dramatic reduction in amyloid deposition in two different transgenic AD models.
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