scholarly journals The Amyloid Precursor Protein (APP) Family Members are Key Players in S-adenosylmethionine Formation by MAT2A and Modify BACE1 and PSEN1 Gene Expression-Relevance for Alzheimer's Disease

2012 ◽  
Vol 11 (11) ◽  
pp. 1274-1288 ◽  
Author(s):  
Andreas Schrötter ◽  
Kathy Pfeiffer ◽  
Fouzi El Magraoui ◽  
Harald W. Platta ◽  
Ralf Erdmann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Senile Plaques ◽  
Mrna Level ◽  
Family Members ◽  
Precursor Protein ◽  
A Cell ◽  
Psen1 Gene

Central hallmark of Alzheimer's disease are senile plaques mainly composed of β-amyloid, which is a cleavage product of the amyloid precursor protein (APP). The physiological function of APP and its family members APLP1 and APLP2 is poorly understood. In order to fill this gap, we established a cell-culture based model with simultaneous knockdown of all members of the family. A comprehensive proteome study of the APP/APLP1/APLP2 knockdown cell lysates versus controls revealed significant protein abundance changes of more than 30 proteins. Targeted validation of selected candidates by immunoblotting supported the significant down-regulation of the methionine adenosyltransferase II, alpha (MAT2A) as well as of peroxiredoxin 4 in the knockdown cells. Moreover, MAT2A was significantly down-regulated at the mRNA level as well. MAT2A catalyzes the production of S-adenosylmethionine from methionine and ATP, which plays a pivotal role in the methylation of neurotransmitters, DNA, proteins, and lipids. MAT2A-dependent significant up-regulation of S-adenosylmethionine was also detectable in the knockdown cells compared with controls. Our results point to a role of the APP family proteins in cellular methylation mechanisms and fit to findings of disturbed S-adenosylmethionine levels in tissue and CSF of Alzheimer disease patients versus controls. Importantly, methylation plays a central role for neurotransmitter generation like acetylcholine pointing to a crucial relevance of our findings for Alzheimer's disease. In addition, we identified differential gene expression of BACE1 and PSEN1 in the knockdown cells, which is possibly a consequence of MAT2A deregulation and may indicate a self regulatory mechanism.

Lentivirus-Mediated Expression of Human Secreted Amyloid Precursor Protein-Alpha Promotes Long-Term Induction of Neuroprotective Genes and Pathways in a Mouse Model of Alzheimer’s Disease

2020 ◽  
pp. 1-16
Author(s):  
Margaret Ryan ◽  
Valerie T.Y. Tan ◽  
Nasya Thompson ◽  
Diane Guévremont ◽  
Bruce G. Mockett ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Amyloid Precursor Protein ◽  
Precursor Protein ◽  
Integrated Analysis ◽  
Empty Vector ◽  
Mouse Transcriptome

Background: Secreted amyloid precursor protein-alpha (sAPPα) can enhance memory and is neurotrophic and neuroprotective across a range of disease-associated insults, including amyloid-β toxicity. In a significant step toward validating sAPPα as a therapeutic for Alzheimer’s disease (AD), we demonstrated that long-term overexpression of human sAPPα (for 8 months) in a mouse model of amyloidosis (APP/PS1) could prevent the behavioral and electrophysiological deficits that develop in these mice. Objective: To explore the underlying molecular mechanisms responsible for the significant physiological and behavioral improvements observed in sAPPα-treated APP/PS1 mice. Methods: We assessed the long-term effects on the hippocampal transcriptome following continuous lentiviral delivery of sAPPα or empty-vector to male APP/PS1 mice and wild-type controls using Affymetrix Mouse Transcriptome Assays. Data analysis was carried out within the Affymetrix Transcriptome Analysis Console and an integrated analysis of the resulting transcriptomic data was performed with Ingenuity Pathway analysis (IPA). Results: Mouse transcriptome assays revealed expected AD-associated gene expression changes in empty-vector APP/PS1 mice, providing validation of the assays used for the analysis. By contrast, there were specific sAPPα-associated gene expression profiles which included increases in key neuroprotective genes such as Decorin, betaine-GABA transporter, and protocadherin beta-5, subsequently validated by qRT-PCR. An integrated biological pathways analysis highlighted regulation of GABA receptor signaling, cell survival, and inflammatory responses. Furthermore, upstream gene regulatory analysis implicated sAPPα activation of Interleukin-4, which can counteract inflammatory changes in AD. Conclusion: This study identified key molecular processes that likely underpin the long-term neuroprotective and therapeutic effects of increasing sAPPα levels in vivo

Protein–protein interactions in the assembly and subcellular trafficking of the BACE (β-site amyloid precursor protein-cleaving enzyme) complex of Alzheimer's disease

2007 ◽  
Vol 35 (5) ◽  
pp. 974-979 ◽  
Author(s):  
R.B. Parsons ◽  
B.M. Austen
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Protein Interactions ◽  
Senile Plaques ◽  
Amyloid Β ◽  
Precursor Protein ◽  
Amyloid Β Peptide ◽  
Aβ Amyloid ◽  
Ad Alzheimer’S Disease

The correct assembly of the BACE (β-site amyloid precursor protein-cleaving enzyme or β-secretase) complex and its subsequent trafficking to cellular compartments where it associates with the APP (amyloid precursor protein) is essential for the production of Aβ (amyloid β-peptide), the protein whose aggregation into senile plaques is thought to be responsible for the pathogenesis of AD (Alzheimer's disease). These processes rely upon both transient and permanent BACE–protein interactions. This review will discuss what is currently known about these BACE–protein interactions and how they may reveal novel therapeutic targets for the treatment of AD.

scholarly journals Impacts of Membrane Biophysics in Alzheimer's Disease: From Amyloid Precursor Protein Processing to AβPeptide-Induced Membrane Changes

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Sholpan Askarova ◽  
Xiaoguang Yang ◽  
James C.-M. Lee
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Conformational Changes ◽  
Senile Plaques ◽  
Critical Role ◽  
Protein A ◽  
Precursor Protein ◽  
Amyloid Precursor Protein Processing ◽  
Membrane Composition

An increasing amount of evidence supports the notion that cytotoxic effects of amyloid-βpeptide (Aβ), the main constituent of senile plaques in Alzheimer's disease (AD), are strongly associated with its ability to interact with membranes of neurons and other cerebral cells. Aβis derived from amyloidogenic cleavage of amyloid precursor protein (AβPP) byβ- andγ-secretase. In the nonamyloidogenic pathway, AβPP is cleaved byα-secretases. These two pathways compete with each other, and enhancing the non-amyloidogenic pathway has been suggested as a potential pharmacological approach for the treatment of AD. Since AβPP,α-,β-, andγ-secretases are membrane-associated proteins, AβPP processing and Aβproduction can be affected by the membrane composition and properties. There is evidence that membrane composition and properties, in turn, play a critical role in Aβcytotoxicity associated with its conformational changes and aggregation into oligomers and fibrils. Understanding the mechanisms leading to changes in a membrane's biophysical properties and how they affect AβPP processing and Aβtoxicity should prove to provide new therapeutic strategies for prevention and treatment of AD.

scholarly journals Nutraceutical and Probiotic Approaches to Examine Molecular Interactions of the Amyloid Precursor Protein APP in Drosophila Models of Alzheimer’s Disease

2021 ◽  
Vol 22 (13) ◽  
pp. 7022
Author(s):  
David Jalali ◽  
Justine Anne Guevarra ◽  
Luz Martinez ◽  
Lily Hung ◽  
Fernando J Vonhoff
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Animal Models ◽  
Amyloid Precursor Protein ◽  
Senile Plaques ◽  
Precursor Protein ◽  
Mammalian Brain ◽  
Shed Light ◽  
Drosophila Models

Studies using animal models have shed light into the molecular and cellular basis for the neuropathology observed in patients with Alzheimer’s disease (AD). In particular, the role of the amyloid precursor protein (APP) plays a crucial role in the formation of senile plaques and aging-dependent degeneration. Here, we focus our review on recent findings using the Drosophila AD model to expand our understanding of APP molecular function and interactions, including insights gained from the fly homolog APP-like (APPL). Finally, as there is still no cure for AD, we review some approaches that have shown promising results in ameliorating AD-associated phenotypes, with special attention on the use of nutraceuticals and their molecular effects, as well as interactions with the gut microbiome. Overall, the phenomena described here are of fundamental significance for understanding network development and degeneration. Given the highly conserved nature of fundamental signaling pathways, the insight gained from animal models such as Drosophila melanogaster will likely advance the understanding of the mammalian brain, and thus be relevant to human health.

scholarly journals A cell-permeable tool for analysing APP intracellular domain function and manipulation of PIKfyve activity

2016 ◽  
Vol 36 (2) ◽  
Author(s):  
Benjamin Guscott ◽  
Zita Balklava ◽  
Stephen T. Safrany ◽  
Thomas Wassmer
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Precursor Protein ◽  
Intracellular Domain ◽  
Central Molecule ◽  
A Cell

In this work we developed and validated a cell permeable tool to study the intracellular function of a central molecule in Alzheimer's disease, the amyloid precursor protein. We showed that it regulates the activity of the PIKfyve kinase complex.

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