Search results

Filter

Filetype

Your search for "*" yielded 530124 hits

Estrogen reduces neuronal generation of Alzheimer β-amyloid peptides

Alzheimer's disease (AD) is characterized by the accumulation of cerebral plaques composed of 40- and 42-amino acid ̄-amyloid (Aβ) peptides, and autosomal dominant forms of AD appear to cause disease by promoting brain Aβ accumulation. Recent studies indicate that postmenopausal estrogen replacement therapy may prevent or delay the onset of AD. Here we present evidence that physiological levels of

Generation and regulation of β-amyloid peptide variants by neurons

Studies of processing of the Alzheimer β-amyloid precursor protein (βAPP) have been performed to date mostly in continuous cell lines and indicate the existence of two principal metabolic pathways: the 'β- secretase' pathway, which generates β-amyloid (Aβ(1-40/42); ~4 kDa), and the 'α-secretase' pathway, which generates a smaller fragment, the 'p3' peptide (Aβ(17-40/42); ~3 kDa). To determine whet

Intraneuronal β-amyloid expression downregulates the Akt survival pathway and blunts the stress response

Early events in Alzheimer's disease (AD) pathogenesis implicate the accumulation of β-amyloid (Aβ) peptide inside neurons in vulnerable brain regions. However, little is known about the consequences of intraneuronal Aβ on signaling mechanisms. Here, we demonstrate, using an inducible viral vector system to drive intracellular expression of Aβ42 peptide in primary neuronal cultures, that this accum

The Arctic Alzheimer mutation favors intracellular amyloid-β production by making amyloid precursor protein less available to α-secretase

Mutations within the amyloid-β (Aβ) domain of the amyloid precursor protein (APP) typically generate hemorrhagic strokes and vascular amyloid angiopathy. In contrast, the Arctic mutation (APP E693G) results in Alzheimer's disease. Little is known about the pathologic mechanisms that result from the Arctic mutation, although increased formation of Aβ protofibrils in vitro and intraneuronal Aβ aggre

Conditional inactivation of presenilin 1 prevents amyloid accumulation and temporarily rescues contextual and spatial working memory impairments in amyloid precursor protein transgenic mice

Accumulation of β-amyloid (Aβ) peptides in the cerebral cortex is considered a key event in the pathogenesis of Alzheimer's disease (AD). Presenilin 1 (PS1) plays an essential role in the γ-secretase cleavage of the amyloid precursor protein (APP) and the generation of Aβ peptides. Reduction of Aβ generation via the inhibition of γ-secretase activity, therefore, has been proposed as a therapeutic

Amyloid-β oligomers are inefficiently measured by enzyme-linked immunosorbent assay

Amyloid-β (Aβ) peptide levels are widely measured by enzyme-linked immunosorbent assay (ELISA) in Alzheimer's disease research. Here, we show that oligomerization of Aβ results in underestimated Aβ ELISA levels. The implications are that comprehensive analysis of soluble Aβ requires either sample pretreatment at denaturing conditions or novel conformation-dependent immunoassays. Our findings might

Stimulation of β-amyloid precursor protein trafficking by insulin reduces intraneuronal β-amyloid and requires mitogen-activated protein kinase signaling

Alzheimer's Disease (AD) is characterized by cerebral accumulation of β-amyloid peptides (Aβ), which are proteolytically derived from β-amyloid precursor protein (βAPP). βAPP metabolism is highly regulated via various signal transduction systems, e.g., several serine/threonine kinases and phosphatases. Several growth factors known to act via receptor tyrosine kinases also have been demonstrated to

More Aware Through Repair : Educating about critical raw materials

The issue of Critical Raw Materials (CRMs) and potential interruptions to their availability due to shortages, trade restrictions or other factors in their supply are topics that are relatively unknown to the general public. For this reason, education has been promoted as a key enabler of a circular economy. One key intervention point is the movement of electronic repair events. Repair events alre

Evidence for phosphorylation and oligomeric assembly of presenilin 1

Pathogenic mutations in presenilin 1 (PS1) are associated with ≃50% of early-onset familial Alzheimer disease. PS1 is endoproteolytically cleaved to yield a 30-kDa N-terminal fragment (NTF) and an 18-kDa C-terminal fragment (CTF). Using COS7 cells transfected with human PS1, we have found that phorbol 12,13-dibutyrate and forskolin increase the state of phosphorylation of serine residues of the hu

Endoplasmic reticulum and trans-Golgi network generate distinct populations of Alzheimer β-amyloid peptides

The excessive generation and accumulation of 40- and 42-aa β-amyloid peptides (Aβ40/Aβ42) in selectively vulnerable brain regions is a major neuropathological feature of Alzheimer's disease. Aβ, derived by proteolytic cleavage from the β-amyloid precursor protein (βAPP), is normally secreted. However, recent evidence suggests that significant levels of Aβ also may remain inside cells. Here, we hav

Increased apolipoprotein E ε4 in epilepsy with senile plaques

Inheritance of the apolipoprotein E (ApoE) ε4 allele is a risk factor for Alzheimer's disease (AD) and is associated with increased deposition of β-amyloid (Aβ) in AD, Down's syndrome, and normal aging. Aβ deposition in the form of senile plaques (SPs) has recently been described in patients with temporal lobe epilepsy (TLE). We studied the relationship between ApoE ε4 genotype and the deposition

Tyrosine-hydroxylase-containing neurons in the primate basal forebrain magnocellular complex

Immunocytochemistry and in situ hybridization for tyrosine hydroxylase (TH) were used to study the distribution of putative catecholaminergic neurons in the basal forebrain magnocellular complex (BFMC) of monkeys and humans. Magnocellular TH-expressing neurons in the primate BFMC are distributed along a rostrocaudal gradient, with the largest proportion of these cells located in the medial septal

Highly selective effects of nerve growth factor, brain‐derived neurotrophic factor, and neurotrophin‐3 on intact and injured basal forebrain magnocellular neurons

Cholinergic neurons of the basal nucleus complex (BNC) respond to nerve growth factor (NCF), the first member of a polypeptide gene family that also includes brain‐derived neurotrophic factor (BDNF), neurotrophin‐3 (NT‐3), and neurotrophin‐4/5 (NT‐4/5), NGF, BDNF, and NT‐3 are enriched in hippocampus. In addition, NGF and, more recently, BDNF have been shown to stimulate the cholinergic differenti

Alzheimer β-amyloid peptides : Normal and abnormal localization

Alzheimer's disease (AD) neuropathology is characterized by accumulation of "senile" plaques (SPs) and neurofibrillary tangles (NFTs) in vulnerable brain regions. SPs are principally composed of aggregates of up to 42/43 amino acid β-amyloid (Aβ) peptides. The discovery of familial AD (FAD) mutations in the genes for the amyloid precursor protein (APP) and presenilins (PSs), all of which increase

Immunotherapy for Alzheimer disease

Immunotherapy approaches for Alzheimer disease currently are among the leading therapeutic directions for the disease. Active and passive immunotherapy against the β-amyloid peptides that aggregate and accumulate in the brain of those afflicted by the disease have been shown by numerous groups to reduce plaque pathology and improve behavior in transgenic mouse models of the disease. Several ongoin