Browse
Submit Data
Databases
API
Help

Dataset Information

33 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Amyloid precursor protein elevates fusion of promyelocytic leukemia nuclear bodies in human hippocampal areas with high plaque load.

ABSTRACT: The amyloid precursor protein (APP) is a type I transmembrane protein with unknown physiological function but potential impact in neurodegeneration. The current study demonstrates that APP signals to the nucleus causing the generation of aggregates consisting of its adapter protein FE65, the histone acetyltransferase TIP60 and the tumour suppressor proteins p53 and PML. APP C-terminal (APP-CT50) complexes co-localize and co-precipitate with p53 and PML. The PML nuclear body generation is induced and fusion occurs over time depending on APP signalling and STED imaging revealed active gene expression within the complex. We further show that the nuclear aggregates of APP-CT50 fragments together with PML and FE65 are present in the aged human brain but not in cerebral organoids differentiated from iPS cells. Notably, human Alzheimer's disease brains reveal a highly significant reduction of these nuclear aggregates in areas with high plaque load compared to plaque-free areas of the same individual. Based on these results we conclude that APP-CT50 signalling to the nucleus takes place in the aged human brain and is involved in the pathophysiology of AD.

SUBMITTER: Marks D

PROVIDER: S-EPMC8042982 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Hippocampal neuron loss exceeds amyloid plaque load in a transgenic mouse model of Alzheimer's disease.

Project description:According to the "amyloid hypothesis of Alzheimer's disease," beta-amyloid is the primary driving force in Alzheimer's disease pathogenesis. Despite the development of many transgenic mouse lines developing abundant beta-amyloid-containing plaques in the brain, the actual link between amyloid plaques and neuron loss has not been clearly established, as reports on neuron loss in these models have remained controversial. We investigated transgenic mice expressing human mutant amyloid precursor protein APP751 (KM670/671NL and V717I) and human mutant presenilin-1 (PS-1 M146L). Stereologic and image analyses revealed substantial age-related neuron loss in the hippocampal pyramidal cell layer of APP/PS-1 double-transgenic mice. The loss of neurons was observed at sites of Abeta aggregation and surrounding astrocytes but, most importantly, was also clearly observed in areas of the parenchyma distant from plaques. These findings point to the potential involvement of more than one mechanism in hippocampal neuron loss in this APP/PS-1 double-transgenic mouse model of Alzheimer's disease.

| S-EPMC1615337 | biostudies-literature

Bacterial sepsis increases hippocampal fibrillar amyloid plaque load and neuroinflammation in a mouse model of Alzheimer's disease.

Project description:BackgroundSepsis, a leading cause for intensive care unit admissions, causes both an acute encephalopathy and chronic brain dysfunction in survivors. A history of sepsis is also a risk factor for future development of dementia symptoms. Similar neuropathologic changes are associated with the cognitive decline of sepsis and Alzheimer's disease (AD), including neuroinflammation, neuronal death, and synaptic loss. Amyloid plaque pathology is the earliest pathological hallmark of AD, appearing 10 to 20 years prior to cognitive decline, and is present in 30% of people over 65. As sepsis is also more common in older adults, we hypothesized that sepsis might exacerbate amyloid plaque deposition and plaque-related injury, promoting the progression of AD-related pathology.MethodsWe evaluated whether the brain's response to sepsis modulates AD-related neurodegenerative changes by driving amyloid deposition and neuroinflammation in mice. We induced polymicrobial sepsis by cecal ligation and puncture (CLP) in APP/PS1-21 mice, a model of AD-related β-amyloidosis. We performed CLP or sham surgery at plaque onset (2 months of age) and examined pathology 2 months after CLP in surviving mice.ResultsSepsis significantly increased fibrillar amyloid plaque formation in the hippocampus of APP/PS1-21 mice. Sepsis enhanced plaque-related astrocyte activation and complement C4b gene expression in the brain, both of which may play a role in modulating amyloid formation. CLP also caused large scale changes in the gut microbiome of APP/PS1 mice, which have been associated with a pro-amyloidogenic and neuroinflammatory state.ConclusionsOur results suggest that experimental sepsis can exacerbate amyloid plaque deposition and plaque-related inflammation, providing a potential mechanism for increased dementia in older sepsis survivors.

| S-EPMC8057119 | biostudies-literature

ESCRTs regulate amyloid precursor protein sorting in multivesicular bodies and intracellular amyloid-? accumulation.

Project description:Intracellular amyloid-? (A?) accumulation is a key feature of early Alzheimer's disease and precedes the appearance of A? in extracellular plaques. A? is generated through proteolytic processing of amyloid precursor protein (APP), but the intracellular site of A? production is unclear. APP has been localized to multivesicular bodies (MVBs) where sorting of APP onto intraluminal vesicles (ILVs) could promote amyloidogenic processing, or reduce A? production or accumulation by sorting APP and processing products to lysosomes for degradation. Here, we show that APP localizes to the ILVs of a subset of MVBs that also traffic EGF receptor (EGFR), and that it is delivered to lysosomes for degradation. Depletion of the endosomal sorting complexes required for transport (ESCRT) components, Hrs (also known as Hgs) or Tsg101, inhibited targeting of APP to ILVs and the subsequent delivery to lysosomes, and led to increased intracellular A? accumulation. This was accompanied by dramatically decreased A? secretion. Thus, the early ESCRT machinery has a dual role in limiting intracellular A? accumulation through targeting of APP and processing products to the lysosome for degradation, and promoting A? secretion.

| S-EPMC4510853 | biostudies-other

Quantitative Comparison of Dense-Core Amyloid Plaque Accumulation in Amyloid-β Protein Precursor Transgenic Mice.

Project description:There exist several dozen lines of transgenic mice that express human amyloid-β protein precursor (AβPP) with Alzheimer's disease (AD)-linked mutations. AβPP transgenic mouse lines differ in the types and amounts of Aβ that they generate and in their spatiotemporal patterns of expression of Aβ assemblies, providing a toolkit to study Aβ amyloidosis and the influence of Aβ aggregation on brain function. More complete quantitative descriptions of the types of Aβ assemblies present in transgenic mice and in humans during disease progression should add to our understanding of how Aβ toxicity in mice relates to the pathogenesis of AD. Here, we provide a direct quantitative comparison of amyloid plaque burdens and plaque sizes in four lines of AβPP transgenic mice. We measured the fraction of cortex and hippocampus occupied by dense-core plaques, visualized by staining with Thioflavin S, in mice from young adulthood through advanced age. We found that the plaque burdens among the transgenic lines varied by an order of magnitude: at 15 months of age, the oldest age studied, the median cortical plaque burden in 5XFAD mice was already ∼4.5 times that of 21-month-old Tg2576 mice and ∼15 times that of 21-24-month-old rTg9191 mice. Plaque-size distributions changed across the lifespan in a line- and region-dependent manner. We also compared the dense-core plaque burdens in the mice to those measured in a set of pathologically-confirmed AD cases from the Nun Study. Cortical plaque burdens in Tg2576, APPSwePS1ΔE9, and 5XFAD mice eventually far exceeded those measured in the human cohort.

| S-EPMC5272806 | biostudies-literature

NHE6 depletion corrects ApoE4-mediated synaptic impairments and reduces amyloid plaque load.

Project description:Apolipoprotein E4 (ApoE4) is the most important and prevalent risk factor for late-onset Alzheimer's disease (AD). The isoelectric point of ApoE4 matches the pH of the early endosome (EE), causing its delayed dissociation from ApoE receptors and hence impaired endolysosomal trafficking, disruption of synaptic homeostasis, and reduced amyloid clearance. We have shown that enhancing endosomal acidification by inhibiting the EE-specific sodium-hydrogen exchanger 6 (NHE6) restores vesicular trafficking and normalizes synaptic homeostasis. Remarkably and unexpectedly, loss of NHE6 (encoded by the gene Slc9a6) in mice effectively suppressed amyloid deposition even in the absence of ApoE4, suggesting that accelerated acidification of EEs caused by the absence of NHE6 occludes the effect of ApoE on amyloid plaque formation. NHE6 suppression or inhibition may thus be a universal, ApoE-independent approach to prevent amyloid buildup in the brain. These findings suggest a novel therapeutic approach for the prevention of AD by which partial NHE6 inhibition reverses the ApoE4-induced endolysosomal trafficking defect and reduces plaque load.

| S-EPMC8547963 | biostudies-literature

IFN-gamma promotes complement expression and attenuates amyloid plaque deposition in amyloid beta precursor protein transgenic mice.

Project description:Reactive gliosis surrounding amyloid beta (Abeta) plaques is an early feature of Alzheimer's disease pathogenesis and has been postulated to represent activation of the innate immune system in an apparently ineffective attempt to clear or neutralize Abeta aggregates. To evaluate the role of IFN-gamma-mediated neuroinflammation on the evolution of Abeta pathology in transgenic (Tg) mice, we have expressed murine IFN-gamma (mIFN-gamma) in the brains of Abeta precursor protein (APP) Tg mice using recombinant adeno-associated virus serotype 1. Expression of mIFN-gamma in brains of APP TgCRND8 mice results in robust noncell autonomous activation of microglia and astrocytes, and a concomitant significant suppression of Abeta deposition. In these mice, mIFN-gamma expression upregulated multiple glial activation markers, early components of the complement cascade as well as led to infiltration of Ly-6c positive peripheral monocytes but no significant effects on APP levels, APP processing or steady-state Abeta levels were noticed in vivo. Taken together, these results suggest that mIFN-gamma expression in the brain suppresses Abeta accumulation through synergistic effects of activated glia and components of the innate immune system that enhance Abeta aggregate phagocytosis.

| S-EPMC3798002 | biostudies-literature

Secreted Amyloid Precursor Protein-Alpha Promotes Arc Protein Synthesis in Hippocampal Neurons.

Project description:Secreted amyloid precursor protein-? (sAPP?) is a neuroprotective and memory-enhancing molecule, however, the mechanisms through which sAPP? promotes these effects are not well understood. Recently, we have shown that sAPP? enhances cell-surface expression of glutamate receptors. Activity-related cytoskeletal-associated protein Arc (Arg3.1) is an immediate early gene capable of modulating long-term potentiation, long-term depression and homeostatic plasticity through regulation of ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor localization. Accordingly, we hypothesized that sAPP? may enhance synaptic plasticity, in part, by the de novo synthesis of Arc. Using primary cortical and hippocampal neuronal cultures we found that sAPP? (1 nM, 2 h) enhances levels of Arc mRNA and protein. Arc protein levels were increased in both the neuronal somata and dendrites in a Ca2+/calmodulin-dependent protein kinase II-dependent manner. Additionally, dendritic Arc expression was dependent upon activation of mitogen-activated protein kinase and protein kinase G. The enhancement of dendritic Arc protein was significantly reduced by antagonism of N-methyl-D-aspartate (NMDA) and nicotinic acetylcholine (?7nACh) receptors, and fully eliminated by dual application of these antagonists. This effect was further corroborated in area CA1 of acute hippocampal slices. These data suggest sAPP?-regulated plasticity within hippocampal neurons is mediated by cooperation of NMDA and ?7nACh receptors to engage a cascade of signal transduction molecules to enhance the transcription and translation of Arc.

| S-EPMC6702288 | biostudies-literature

Alzheimer precursor protein interaction with the Nogo-66 receptor reduces amyloid-beta plaque deposition.

Project description:Pathophysiologic hypotheses for Alzheimer's disease (AD) are centered on the role of the amyloid plaque Abeta peptide and the mechanism of its derivation from the amyloid precursor protein (APP). As part of the disease process, an aberrant axonal sprouting response is known to occur near Abeta deposits. A Nogo to Nogo-66 receptor (NgR) pathway contributes to determining the ability of adult CNS axons to extend after traumatic injuries. Here, we consider the potential role of NgR mechanisms in AD. Both Nogo and NgR are mislocalized in AD brain samples. APP physically associates with the NgR. Overexpression of NgR decreases Abeta production in neuroblastoma culture, and targeted disruption of NgR expression increases transgenic mouse brain Abeta levels, Abeta plaque deposition, and dystrophic neurites. Infusion of a soluble NgR fragment reduces Abeta levels, amyloid plaque deposits, and dystrophic neurites in a mouse transgenic AD model. Changes in NgR level produce parallel changes in secreted APPalpha and Abeta, implicating NgR as a blocker of secretase processing of APP. The NgR provides a novel site for modifying the course of AD and highlights the role of axonal dysfunction in the disease.

| S-EPMC2846286 | biostudies-literature

Expression and processing of fluorescent fusion proteins of amyloid precursor protein (APP).

Project description:Processing of ?-amyloid precursor protein (APP) by ?- and ?-secretases in neurons produces amyloid-? (A?), whose excess accumulation leads to Alzheimer's disease (AD). Knowledge on subcellular trafficking pathways of APP and its fragments is important for the understanding of AD pathogenesis. We designed fusion proteins comprising a C-terminal fragment of APP (app) and fluorescent proteins GFP (G) and DsRed (D) to permit the tracking of the fusion proteins and fragments in cells. CAD cells expressing these proteins emitted colocalized green and red fluorescence and produce ectodomains, sGapp and sRapp, and A?, whose level was reduced by inhibitors of ?- and ?-secretases. The presence of GappR in endosomes was observed via colocalization with Rab5. These observations indicated that the fusion proteins were membrane inserted, transported in vesicles and proteolytically processed by the same mechanism for APP. By attenuating fusion protein synthesis with cycloheximide, individual fluorescent colors from the C-terminus of the fusion proteins appeared in the cytosol which was strongly suppressed by ?-secretase inhibitor, suggesting that the ectodomains exit the cell rapidly (t1/2 about 20min) while the C-terminal fragments were retained longer in cells. In live cells, we observed the fluorescence of the ectodomains located between parental fusion proteins and plasma membrane, suggesting that these ectodomain positions are part of their secretion pathway. Our results indicate that the native ectodomain does not play a decisive role for the key features of APP trafficking and processing and the new fusion proteins may lead to novel insights in intracellular activities of APP.

| S-EPMC3753662 | biostudies-literature

Role of phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) in intracellular amyloid precursor protein (APP) processing and amyloid plaque pathogenesis.

Project description:One of the pathological hallmarks of Alzheimer disease is the accumulation of amyloid plaques in the extracellular space in the brain. Amyloid plaques are primarily composed of aggregated amyloid β peptide (Aβ), a proteolytic fragment of the transmembrane amyloid precursor protein (APP). For APP to be proteolytically cleaved into Aβ, it must be internalized into the cell and trafficked to endosomes where specific protease complexes can cleave APP. Several recent genome-wide association studies have reported that several single nucleotide polymorphisms (SNPs) in the phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (PICALM) gene were significantly associated with Alzheimer disease, suggesting a role in APP endocytosis and Aβ generation. Here, we show that PICALM co-localizes with APP in intracellular vesicles of N2a-APP cells after endocytosis is initiated. PICALM knockdown resulted in reduced APP internalization and Aβ generation. Conversely, PICALM overexpression increased APP internalization and Aβ production. In vivo, PICALM was found to be expressed in neurons and co-localized with APP throughout the cortex and hippocampus in APP/PS1 mice. PICALM expression was altered using AAV8 gene transfer of PICALM shRNA or PICALM cDNA into the hippocampus of 6-month-old APP/PS1 mice. PICALM knockdown decreased soluble and insoluble Aβ levels and amyloid plaque load in the hippocampus. Conversely, PICALM overexpression increased Aβ levels and amyloid plaque load. These data indicate that PICALM, an adaptor protein involved in clathrin-mediated endocytosis, regulates APP internalization and subsequent Aβ generation. PICALM contributes to amyloid plaque load in brain likely via its effect on Aβ metabolism.

| S-EPMC3375549 | 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