Multilayered N-glycoproteomics reveals impaired N-glycosylation promoting Alzheimer’s disease

ABSTRACTAlzheimer’s disease (AD) is one of the most common neurodegenerative diseases that currently lacks clear pathogenesis and effective treatment. Protein glycosylation is ubiquitous in brain tissue and site-specific analysis of N-glycoproteome, which is technically challenging, can advance our understanding of the glycoproteins’ role in AD. In this study, we profiled the multilayered variations in proteins, N-glycosites, N-glycans, and in particular site-specific N-glycopeptides in the APP/PS1 and wild type mouse brain through combining pGlyco 2.0 strategy with other quantitative N-glycoproteomic strategies. The comprehensive brain N-glycoproteome landscape was constructed, and rich details of the heterogeneous site-specific protein N-glycosylations were exhibited. Quantitative analyses explored generally downregulated N-glycosylation involving proteins such as glutamate receptors, as well as fucosylated and oligo-mannose type glycans in APP/PS1 mice versus wild type mice. Moreover, our preliminary functional study revealed that N-glycosylation was crucial for the membrane localization of NCAM1 and for maintaining the excitability and viability of neuron cells. Our work offered a panoramic view of the N-glycoproteomes in Alzheimer’s disease and revealed that generally impaired N-glycosylation promotes Alzheimer’s disease progression.

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In-depth site-specific analysis of N-glycoproteome in human cerebrospinal fluid (CSF) and glycosylation landscape changes in Alzheimer's disease (AD)

Molecular & Cellular Proteomics ◽

10.1016/j.mcpro.2021.100081 ◽

2021 ◽

pp. 100081

Author(s):

Zhengwei Chen ◽

Qinying Yu ◽

Qing Yu ◽

Jillian Johnson ◽

Richard Shipman ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebrospinal Fluid ◽

Landscape Changes ◽

Site Specific ◽

Human Cerebrospinal Fluid ◽

Specific Analysis

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Faculty Opinions recommendation of GFAP and vimentin deficiency alters gene expression in astrocytes and microglia in wild-type mice and changes the transcriptional response of reactive glia in mouse model for Alzheimer's disease.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725374290.793547530 ◽

2018 ◽

Author(s):

Michael Klymkowsky

Keyword(s):

Gene Expression ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Transcriptional Response ◽

Wild Type ◽

Reactive Glia

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The Role of Lipids and Membranes in the Pathogenesis of Alzheimer's Disease: A Comprehensive View

Current Alzheimer Research ◽

10.2174/1567205015666180911151716 ◽

2018 ◽

Vol 15 (13) ◽

pp. 1191-1212 ◽

Cited By ~ 23

Author(s):

Botond Penke ◽

Gábor Paragi ◽

János Gera ◽

Róbert Berkecz ◽

Zsolt Kovács ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Signaling Pathways ◽

Membrane Lipids ◽

Specific Protein ◽

Dietary Factors ◽

Lipid Signaling ◽

Special Role ◽

Aβ Peptides

Lipids participate in Amyloid Precursor Protein (APP) trafficking and processing - important factors in the initiation of Alzheimer’s disease (AD) pathogenesis and influence the formation of neurotoxic β-amyloid (Aβ) peptides. An important risk factor, the presence of ApoE4 protein in AD brain cells binds the lipids to AD. In addition, lipid signaling pathways have a crucial role in the cellular homeostasis and depend on specific protein-lipid interactions. The current review focuses on pathological alterations of membrane lipids (cholesterol, glycerophospholipids, sphingolipids) and lipid metabolism in AD and provides insight in the current understanding of biological membranes, their lipid structures and functions, as well as their role as potential therapeutic targets. Novel methods for studying the membrane structure and lipid composition will be reviewed in a broad sense whereas the use of lipid biomarkers for early diagnosis of AD will be shortly summarized. Interactions of Aβ peptides with the cell membrane and different subcellular organelles are reviewed. Next, the details of the most important lipid signaling pathways, including the role of the plasma membrane as stress sensor and its therapeutic applications are given. 4-hydroxy-2-nonenal may play a special role in the initiation of the pathogenesis of AD and thus the “calpain-cathepsin hypothesis” of AD is highlighted. Finally, the most important lipid dietary factors and their possible use and efficacy in the prevention of AD are discussed.

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[18F]-florbetaben PET/CT Imaging in the Alzheimer’s Disease Mouse Model APPswe/PS1dE9

Current Alzheimer Research ◽

10.2174/1567205015666181022095904 ◽

2018 ◽

Vol 16 (1) ◽

pp. 49-55 ◽

Cited By ~ 1

Author(s):

J. Stenzel ◽

C. Rühlmann ◽

T. Lindner ◽

S. Polei ◽

S. Teipel ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

New Drugs ◽

Imaging Data ◽

Wild Type ◽

Preclinical Research ◽

Standardized Uptake Values ◽

Pet Ct

Background: Positron-emission-tomography (PET) using 18F labeled florbetaben allows noninvasive in vivo-assessment of amyloid-beta (Aβ), a pathological hallmark of Alzheimer’s disease (AD). In preclinical research, [18F]-florbetaben-PET has already been used to test the amyloid-lowering potential of new drugs, both in humans and in transgenic models of cerebral amyloidosis. The aim of this study was to characterize the spatial pattern of cerebral uptake of [18F]-florbetaben in the APPswe/ PS1dE9 mouse model of AD in comparison to histologically determined number and size of cerebral Aβ plaques. Methods: Both, APPswe/PS1dE9 and wild type mice at an age of 12 months were investigated by smallanimal PET/CT after intravenous injection of [18F]-florbetaben. High-resolution magnetic resonance imaging data were used for quantification of the PET data by volume of interest analysis. The standardized uptake values (SUVs) of [18F]-florbetaben in vivo as well as post mortem cerebral Aβ plaque load in cortex, hippocampus and cerebellum were analyzed. Results: Visual inspection and SUVs revealed an increased cerebral uptake of [18F]-florbetaben in APPswe/ PS1dE9 mice compared with wild type mice especially in the cortex, the hippocampus and the cerebellum. However, SUV ratios (SUVRs) relative to cerebellum revealed only significant differences in the hippocampus between the APPswe/PS1dE9 and wild type mice but not in cortex; this differential effect may reflect the lower plaque area in the cortex than in the hippocampus as found in the histological analysis. Conclusion: The findings suggest that histopathological characteristics of Aβ plaque size and spatial distribution can be depicted in vivo using [18F]-florbetaben in the APPswe/PS1dE9 mouse model.

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NF-κB as a Key Mediator of Brain Inflammation in Alzheimer’s Disease

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527316666170807130011 ◽

2019 ◽

Vol 18 (1) ◽

pp. 3-10 ◽

Cited By ~ 18

Author(s):

Chul Ju Hwang ◽

Dong-Young Choi ◽

Mi Hee Park ◽

Jin Tae Hong

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Treatment Strategies ◽

Close Correlation ◽

Specific Protein ◽

Brain Inflammation ◽

Cytokines And Chemokines ◽

Inflammatory Drugs ◽

Peptide Fibrils

Alzheimer’s disease is the most common form of dementia. It is characterized by betaamyloid peptide fibrils which are extracellular deposition of a specific protein, accompanied by extensive neuroinflammation. Various studies show the presence of a number of inflammation markers in the AD brain: elevated inflammatory cytokines and chemokines, and an accumulation of activated microglia in the damaged regions. NF-κB is a family of redox sensitive transcriptional factors, and it is known that NF-κB has binding sites in the promoter region of the genes involved in amyloidogenesis and inflammation. Long-term use of non-steroidal anti-inflammatory drugs prevents progression of AD and delays its onset, suggesting that there is a close correlation between NF-κB and AD pathogenesis. This study aims to (1) assess the association between NF-κB activity and AD through discussion of a variety of experimental and clinical studies on AD and (2) review treatment strategies designed to treat or prevent AD with NF-κB inhibitors.

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Transcriptome analyses of 7-day-old zebrafish larvae possessing a familial Alzheimer’s disease-like mutation in psen1 indicate effects on oxidative phosphorylation, ECM and MCM functions, and iron homeostasis

BMC Genomics ◽

10.1186/s12864-021-07509-1 ◽

2021 ◽

Vol 22 (1) ◽

Cited By ~ 1

Author(s):

Yang Dong ◽

Morgan Newman ◽

Stephen M. Pederson ◽

Karissa Barthelson ◽

Nhi Hin ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Oxidative Phosphorylation ◽

Transcriptome Analysis ◽

Iron Homeostasis ◽

Late Onset ◽

Wild Type ◽

Familial Alzheimer’S Disease ◽

Zebrafish Larvae ◽

Familial Alzheimer's Disease

Abstract Background Early-onset familial Alzheimer’s disease (EOfAD) is promoted by dominant mutations, enabling the study of Alzheimer’s disease (AD) pathogenic mechanisms through generation of EOfAD-like mutations in animal models. In a previous study, we generated an EOfAD-like mutation, psen1Q96_K97del, in zebrafish and performed transcriptome analysis comparing entire brains from 6-month-old wild type and heterozygous mutant fish. We identified predicted effects on mitochondrial function and endolysosomal acidification. Here we aimed to determine whether similar effects occur in 7 day post fertilization (dpf) zebrafish larvae that might be exploited in screening of chemical libraries to find ameliorative drugs. Results We generated clutches of wild type and heterozygous psen1Q96_K97del 7 dpf larvae using a paired-mating strategy to reduce extraneous genetic variation before performing a comparative transcriptome analysis. We identified 228 differentially expressed genes and performed various bioinformatics analyses to predict cellular functions. Conclusions Our analyses predicted a significant effect on oxidative phosphorylation, consistent with our earlier observations of predicted effects on ATP synthesis in adult heterozygous psen1Q96_K97del brains. The dysregulation of minichromosome maintenance protein complex (MCM) genes strongly contributed to predicted effects on DNA replication and the cell cycle and may explain earlier observations of genome instability due to PSEN1 mutation. The upregulation of crystallin gene expression may be a response to defective activity of mutant Psen1 protein in endolysosomal acidification. Genes related to extracellular matrix (ECM) were downregulated, consistent with previous studies of EOfAD mutant iPSC neurons and postmortem late onset AD brains. Also, changes in expression of genes controlling iron ion transport were observed without identifiable changes in the prevalence of transcripts containing iron responsive elements (IREs) in their 3′ untranslated regions (UTRs). These changes may, therefore, predispose to the apparent iron dyshomeostasis previously observed in 6-month-old heterozygous psen1Q96_K97del EOfAD-like mutant brains.

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Pharmacological ablation of astrocytes reduces Aβ degradation and synaptic connectivity in an ex vivo model of Alzheimer’s disease

Journal of Neuroinflammation ◽

10.1186/s12974-021-02117-y ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Nicola Davis ◽

Bibiana C. Mota ◽

Larissa Stead ◽

Emily O. C. Palmer ◽

Laura Lombardero ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Culture Media ◽

Ex Vivo ◽

Wild Type ◽

Insulin Degrading Enzyme ◽

Ex Vivo Model ◽

Model Of Alzheimer’S Disease ◽

Aβ Clearance ◽

5Xfad Mice

Abstract Background Astrocytes provide a vital support to neurons in normal and pathological conditions. In Alzheimer’s disease (AD) brains, reactive astrocytes have been found surrounding amyloid plaques, forming an astrocytic scar. However, their role and potential mechanisms whereby they affect neuroinflammation, amyloid pathology, and synaptic density in AD remain unclear. Methods To explore the role of astrocytes on Aβ pathology and neuroinflammatory markers, we pharmacologically ablated them in organotypic brain culture slices (OBCSs) from 5XFAD mouse model of AD and wild-type (WT) littermates with the selective astrocytic toxin L-alpha-aminoadipate (L-AAA). To examine the effects on synaptic circuitry, we measured dendritic spine number and size in OBCSs from Thy-1-GFP transgenic mice incubated with synthetic Aβ42 or double transgenics Thy-1-GFP/5XFAD mice treated with LAAA or vehicle for 24 h. Results Treatment of OBCSs with L-AAA resulted in an increased expression of pro-inflammatory cytokine IL-6 in conditioned media of WTs and 5XFAD slices, associated with changes in microglia morphology but not in density. The profile of inflammatory markers following astrocytic loss was different in WT and transgenic cultures, showing reductions in inflammatory mediators produced in astrocytes only in WT sections. In addition, pharmacological ablation of astrocytes led to an increase in Aβ levels in homogenates of OBCS from 5XFAD mice compared with vehicle controls, with reduced enzymatic degradation of Aβ due to lower neprilysin and insulin-degrading enzyme (IDE) expression. Furthermore, OBSCs from wild-type mice treated with L-AAA and synthetic amyloid presented 56% higher levels of Aβ in culture media compared to sections treated with Aβ alone, concomitant with reduced expression of IDE in culture medium, suggesting that astrocytes contribute to Aβ clearance and degradation. Quantification of hippocampal dendritic spines revealed a reduction in their density following L-AAA treatment in all groups analyzed. In addition, pharmacological ablation of astrocytes resulted in a decrease in spine size in 5XFAD OBCSs but not in OBCSs from WT treated with synthetic Aβ compared to vehicle control. Conclusions Astrocytes play a protective role in AD by aiding Aβ clearance and supporting synaptic plasticity.

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Proteins and microRNAs are differentially expressed in tear fluid from patients with Alzheimer’s disease

Scientific Reports ◽

10.1038/s41598-019-51837-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Aidan Kenny ◽

Eva M. Jiménez-Mateos ◽

María Ascensión Zea-Sevilla ◽

Alberto Rábano ◽

Pablo Gili-Manzanaro ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Unmet Need ◽

Cost Effective ◽

Specific Protein ◽

Tear Fluid ◽

Initiation Factor ◽

Non Invasive ◽

A Genome ◽

Potential Biomarker

Abstract Alzheimer’s disease (AD) is characterized by a progressive loss of neurons and cognitive functions. Therefore, early diagnosis of AD is critical. The development of practical and non-invasive diagnostic tests for AD remains, however, an unmet need. In the present proof-of-concept study we investigated tear fluid as a novel source of disease-specific protein and microRNA-based biomarkers for AD development using samples from patients with mild cognitive impairment (MCI) and AD. Tear protein content was evaluated via liquid chromatography-mass spectrometry and microRNA content was profiled using a genome-wide high-throughput PCR-based platform. These complementary approaches identified enrichment of specific proteins and microRNAs in tear fluid of AD patients. In particular, we identified elongation initiation factor 4E (eIF4E) as a unique protein present only in AD samples. Total microRNA abundance was found to be higher in tears from AD patients. Among individual microRNAs, microRNA-200b-5p was identified as a potential biomarker for AD with elevated levels present in AD tear fluid samples compared to controls. Our study suggests that tears may be a useful novel source of biomarkers for AD and that the identification and verification of biomarkers within tears may allow for the development of a non-invasive and cost-effective diagnostic test for AD.

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E22Δ Mutation in Amyloidβ-Protein Promotesβ-Sheet Transformation, Radical Production, and Synaptotoxicity, But Not Neurotoxicity

International Journal of Alzheimer s Disease ◽

10.4061/2011/431320 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Takayuki Suzuki ◽

Kazuma Murakami ◽

Naotaka Izuo ◽

Toshiaki Kume ◽

Akinori Akaike ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Conformational Change ◽

Deletion Mutant ◽

Protein A ◽

Type A ◽

Synaptic Dysfunction ◽

Wild Type ◽

Radical Production

Oligomers of 40- or 42-mer amyloidβ-protein (Aβ40, Aβ42) cause cognitive decline and synaptic dysfunction in Alzheimer's disease. We proposed the importance of a turn at Glu22 and Asp23 of Aβ42 to induce its neurotoxicity through the formation of radicals. Recently, a novel deletion mutant at Glu22 (E22Δ) of Aβ42 was reported to accelerate oligomerization and synaptotoxicity. To investigate this mechanism, the effects of the E22Δ mutation in Aβ42 and Aβ40 on the transformation ofβ-sheets, radical production, and neurotoxicity were examined. Both mutants promotedβ-sheet transformation and the formation of radicals, while their neurotoxicity was negative. In contrast, E22P-Aβ42 with a turn at Glu22 and Asp23 exhibited potent neurotoxicity along with the ability to form radicals and potent synaptotoxicity. These data suggest that conformational change in E22Δ-Aβis similar to that in E22P-Aβ42 but not the same, since E22Δ-Aβ42 exhibited no cytotoxicity, unlike E22P-Aβ42 and wild-type Aβ42.

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