Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Decreased clearance of CNS beta-amyloid in Alzheimer's disease.

ABSTRACT: Alzheimer's disease is hypothesized to be caused by an imbalance between ?-amyloid (A?) production and clearance that leads to A? accumulation in the central nervous system (CNS). A? production and clearance are key targets in the development of disease-modifying therapeutic agents for Alzheimer's disease. However, there has not been direct evidence of altered A? production or clearance in Alzheimer's disease. By using metabolic labeling, we measured A?42 and A?40 production and clearance rates in the CNS of participants with Alzheimer's disease and cognitively normal controls. Clearance rates for both A?42 and A?40 were impaired in Alzheimer's disease compared with controls. On average, there were no differences in A?40 or A?42 production rates. Thus, the common late-onset form of Alzheimer's disease is characterized by an overall impairment in A? clearance.

SUBMITTER: Mawuenyega KG

PROVIDER: S-EPMC3073454 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Decreased clearance of CNS beta-amyloid in Alzheimer's disease.

Mawuenyega Kwasi G KG Sigurdson Wendy W Ovod Vitaliy V Munsell Ling L Kasten Tom T Morris John C JC Yarasheski Kevin E KE Bateman Randall J RJ

Science (New York, N.Y.) 20101209 6012

Alzheimer's disease is hypothesized to be caused by an imbalance between β-amyloid (Aβ) production and clearance that leads to Aβ accumulation in the central nervous system (CNS). Aβ production and clearance are key targets in the development of disease-modifying therapeutic agents for Alzheimer's disease. However, there has not been direct evidence of altered Aβ production or clearance in Alzheimer's disease. By using metabolic labeling, we measured Aβ42 and Aβ40 production and clearance rates ...[more]

PMID: 21148344

Similar Datasets

Microglial dysfunction and defective beta-amyloid clearance pathways in aging Alzheimer's disease mice.

Project description:Early microglial accumulation in Alzheimer's disease (AD) delays disease progression by promoting clearance of beta-amyloid (Abeta) before formation of senile plaques. However, persistent Abeta accumulation despite increasing microglial numbers suggests that the ability of microglia to clear Abeta may decrease with age and progression of AD pathology. To determine the effects of aging and Abeta deposition on microglial ability to clear Abeta, we used quantitative PCR to analyze gene expression in freshly isolated adult microglia from 1.5-, 3-, 8-, and 14-month-old transgenic PS1-APP mice, an established mouse model of AD, and from their nontransgenic littermates. We found that microglia from old PS1-APP mice, but not from younger mice, have a twofold to fivefold decrease in expression of the Abeta-binding scavenger receptors scavenger receptor A (SRA), CD36, and RAGE (receptor for advanced-glycosylation endproducts), and the Abeta-degrading enzymes insulysin, neprilysin, and MMP9, compared with their littermate controls. In contrast, PS1-APP microglia had a 2.5-fold increase in the proinflammatory cytokines IL-1beta (interleukin-1beta) and tumor necrosis factor alpha (TNFalpha), suggesting that there is an inverse correlation between cytokine production and Abeta clearance. In support of this possibility, we found that incubation of cultured N9 mouse microglia with TNFalpha decreased the expression of SRA and CD36 and reduced Abeta uptake. Our data indicate that, although early microglial recruitment promotes Abeta clearance and is neuroprotective in AD, as disease progresses, proinflammatory cytokines produced in response to Abeta deposition downregulate genes involved in Abeta clearance and promote Abeta accumulation, therefore contributing to neurodegeneration. Antiinflammatory therapy for AD should take this dichotomous microglial role into consideration.

| S-EPMC2597474 | biostudies-literature

Amyloid-beta Citrullination in Alzheimer's Disease

Project description:Amyloid-beta peptides which aggregate and accumulate in Alzheimer’s disease (AD) brain are known to have sequential N-terminal truncations and multiple post-translational modifications (PTM) such as isomerization, pyroglutamate formation, phosphorylation, nitration and dityrosine cross-linking. Here we add to the list of PTM citrullination (deimination) of Arg5 residue in plaque-derived Abeta in sporadic AD brains, identified by tandem mass spectrometry. We quantitated the level of citrullination on multiple N-truncated Abeta isoforms present in plaque-associated fractions and found that almost 30 % of pyroGlu3-Abeta pool was citrullinated in plaques from AD temporal cortex. We also documented citrullinated Abeta peptides in the detergent insoluble fractions from AD frontal cortex with ~ 22 % citrullination in the pyroGlu3-Abeta pool. Citrullination of Abeta is a common PTM, closely associated with pyroglutamate-Abeta formation and Abeta accumulation in AD. This may have implications for Abeta toxicity, auto-antigenicity of Abeta, and may be relevant for the design of diagnostic assays and therapeutic targeting.

2021-11-24 | PXD025620 | Pride

Physiological amyloid-beta clearance in the periphery and its therapeutic potential for Alzheimer's disease.

Project description:Amyloid-beta (Aβ) plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The physiological capacity of peripheral tissues and organs in clearing brain-derived Aβ and its therapeutic potential for AD remains largely unknown. Here, we measured blood Aβ levels in different locations of the circulation in humans and mice, and used a parabiosis model to investigate the effect of peripheral Aβ catabolism on AD pathogenesis. We found that blood Aβ levels in the inferior/posterior vena cava were lower than that in the superior vena cava in both humans and mice. In addition, injected (125)I labeled Aβ40 was located mostly in the liver, kidney, gastrointestinal tract, and skin but very little in the brain; suggesting that Aβ derived from the brain can be cleared in the periphery. Parabiosis before and after Aβ deposition in the brain significantly reduced brain Aβ burden without alterations in the expression of amyloid precursor protein, Aβ generating and degrading enzymes, Aβ transport receptors, and AD-type pathologies including hyperphosphorylated tau, neuroinflammation, as well as neuronal degeneration and loss in the brains of parabiotic AD mice. Our study revealed that the peripheral system is potent in clearing brain Aβ and preventing AD pathogenesis. The present work suggests that peripheral Aβ clearance is a valid therapeutic approach for AD, and implies that deficits in the Aβ clearance in the periphery might also contribute to AD pathogenesis.

| S-EPMC4575389 | biostudies-literature

LC3-Associated Endocytosis Facilitates β-Amyloid Clearance and Mitigates Neurodegeneration in Murine Alzheimer's Disease.

Project description: Not available

| S-EPMC7805021 | biostudies-literature

LC3-Associated Endocytosis Facilitates β-Amyloid Clearance and Mitigates Neurodegeneration in Murine Alzheimer's Disease.

Project description:The expression of some proteins in the autophagy pathway declines with age, which may impact neurodegeneration in diseases, including Alzheimer's Disease. We have identified a novel non-canonical function of several autophagy proteins in the conjugation of LC3 to Rab5+, clathrin+ endosomes containing β-amyloid in a process of LC3-associated endocytosis (LANDO). We found that LANDO in microglia is a critical regulator of immune-mediated aggregate removal and microglial activation in a murine model of AD. Mice lacking LANDO but not canonical autophagy in the myeloid compartment or specifically in microglia have a robust increase in pro-inflammatory cytokine production in the hippocampus and increased levels of neurotoxic β-amyloid. This inflammation and β-amyloid deposition were associated with reactive microgliosis and tau hyperphosphorylation. LANDO-deficient AD mice displayed accelerated neurodegeneration, impaired neuronal signaling, and memory deficits. Our data support a protective role for LANDO in microglia in neurodegenerative pathologies resulting from β-amyloid deposition.

| S-EPMC6689199 | biostudies-literature

Heparanase overexpression impedes perivascular clearance of amyloid-β from murine brain: relevance to Alzheimer's disease.

Project description:Defective amyloid-β (Aβ) clearance from the brain is a major contributing factor to the pathophysiology of Alzheimer's disease (AD). Aβ clearance is mediated by macrophages, enzymatic degradation, perivascular drainage along the vascular basement membrane (VBM) and transcytosis across the blood-brain barrier (BBB). AD pathology is typically associated with cerebral amyloid angiopathy due to perivascular accumulation of Aβ. Heparan sulfate (HS) is an important component of the VBM, thought to fulfill multiple roles in AD pathology. We previously showed that macrophage-mediated clearance of intracortically injected Aβ was impaired in the brains of transgenic mice overexpressing heparanase (Hpa-tg). This study revealed that perivascular drainage was impeded in the Hpa-tg brain, evidenced by perivascular accumulation of the injected Aβ in the thalamus of Hpa-tg mice. Furthermore, endogenous Aβ accumulated at the perivasculature of Hpa-tg thalamus, but not in control thalamus. This perivascular clearance defect was confirmed following intracortical injection of dextran that was largely retained in the perivasculature of Hpa-tg brains, compared to control brains. Hpa-tg brains presented with thicker VBMs and swollen perivascular astrocyte endfeet, as well as elevated expression of the BBB-associated water-pump protein aquaporin 4 (AQP4). Elevated levels of both heparanase and AQP4 were also detected in human AD brain. These findings indicate that elevated heparanase levels alter the organization and composition of the BBB, likely through increased fragmentation of BBB-associated HS, resulting in defective perivascular drainage. This defect contributes to perivascular accumulation of Aβ in the Hpa-tg brain, highlighting a potential role for heparanase in the pathogenesis of AD.

| S-EPMC8111754 | biostudies-literature

Beta Amyloid toxicity in a Caenorhabditis elegans model of Alzheimer's disease

Project description:Transgenic animals were engineered to express human amyloid peptide controlled by a muscle-specific, heat-inducible promoter. At low temperatures (16°C) Abeta expression is minimal, while at higher temperatures (20-25°C) Abeta accummulates in large quantities and causes paralysis. GFP- and GFP::degron (a toxic aggregating GFP mutant)-expressing animals were used as controls. Animals were grown at 16°C till early 3rd larval stage and then upshifted to 25°C. Animals were harvested at the time of upshift (T0), and every 4 hours later until 20 hours postupshift (T4-T20).

2015-02-12 | E-GEOD-65851 | biostudies-arrayexpress

Neuronal microRNA response to Alzheimer's disease amyloid beta

Project description:In neurodegenerative disorders such as Alzheimer’s disease (AD), brain miRNA profiles are altered; thus miRNA dysfunction could be both a cause and a consequence of disease. Our study dissects the complexity of human AD pathology, in the absence of a post mortem delay, and provides the first miRNA profiling analysis addressing the contribution of amyloid-β (Aβ), a known causative factor of AD, to the de-regulation of neuronal miRNA expression. We used murine primary hippocampal neurons to show that Aβ is a powerful regulator of mature miRNA expression and a prominent miRNA down-regulation is evoked in response to Aβ peptides. Our study provides insight into a previously unexplored mechanism of how Aβ may impact the pathology of AD and identification of key miRNAs affected by Aβ will allow further analysis on target genes and biological pathways contributing to AD pathomechanisms.

2010-05-30 | GSE20447 | GEO

Heat shock proteins and amateur chaperones in amyloid-Beta accumulation and clearance in Alzheimer's disease.

Project description:The pathologic lesions of Alzheimer's disease (AD) are characterized by accumulation of protein aggregates consisting of intracellular or extracellular misfolded proteins. The amyloid-beta (Abeta) protein accumulates extracellularly in senile plaques and cerebral amyloid angiopathy, whereas the hyperphosphorylated tau protein accumulates intracellularly as neurofibrillary tangles. "Professional chaperones", such as the heat shock protein family, have a function in the prevention of protein misfolding and subsequent aggregation. "Amateur" chaperones, such as apolipoproteins and heparan sulfate proteoglycans, bind amyloidogenic proteins and may affect their aggregation process. Professional and amateur chaperones not only colocalize with the pathological lesions of AD, but may also be involved in conformational changes of Abeta, and in the clearance of Abeta from the brain via phagocytosis or active transport across the blood-brain barrier. Thus, both professional and amateur chaperones may be involved in the aggregation, accumulation, persistence, and clearance of Abeta and tau and in other Abeta-associated reactions such as inflammation associated with AD lesions, and may, therefore, serve as potential targets for therapeutic intervention.

| S-EPMC2039847 | biostudies-other

Robust amyloid clearance in a mouse model of Alzheimer's disease provides novel insights into the mechanism of amyloid-beta immunotherapy.

Project description:Many new therapeutics for Alzheimer's disease delay the accumulation of amyloid-? (A?) in transgenic mice, but evidence for clearance of preexisting plaques is often lacking. Here, we demonstrate that anti-A? immunotherapy combined with suppression of A? synthesis allows significant removal of antecedent deposits. We treated amyloid-bearing tet-off APP (amyloid precursor protein) mice with doxycycline to suppress transgenic A? production before initiating a 12 week course of passive immunization. Animals remained on doxycycline for 3 months afterward to assess whether improvements attained during combined treatment could be maintained by monotherapy. This strategy reduced amyloid load by 52% and A?42 content by 28% relative to pretreatment levels, with preferential clearance of small deposits and diffuse A? surrounding fibrillar cores. We demonstrate that peripherally administered anti-A? antibody crossed the blood-brain barrier, bound to plaques, and was still be found associated with a subset of amyloid deposits many months after the final injection. Antibody accessed the brain independent of plasma A? levels, where it enhanced microglial internalization of aggregated A?. Our data support a mechanism by which passive immunization acts centrally to stimulate microglial phagocytosis of aggregated A?, but is opposed by the continued aggregation of newly secreted A?. By arresting the production of A?, combination therapy allows microglial clearance to work from a static amyloid burden toward a significant reduction in plaque load. Our findings suggest that combining two therapeutic approaches currently in clinical trials may improve neuropathological outcome over either alone.

| S-EPMC3074951 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data