scholarly journals Epigenome-wide study uncovers tau pathology-driven changes of chromatin organization in the aging human brain

2018 ◽  
Author(s):  
Hans-Ulrich Klein ◽  
Cristin McCabe ◽  
Elizabeta Gjoneska ◽  
Sarah E. Sullivan ◽  
Belinda J. Kaskow ◽  
...  
Keyword(s):  
Human Brain ◽  
Mouse Models ◽  
Tau Protein ◽  
Large Scale ◽  
Amyloid Β ◽  
Nuclear Lamina ◽  
Chromatin Organization ◽  
Tau Pathology ◽  
Transcriptional Changes ◽  
Functional Relevance

SummaryAccumulation of tau and amyloid-β are two pathologic hallmarks of Alzheimer’s disease (AD). Here, we conducted an epigenome-wide association study using the H3K9 acetylation (H3K9Ac) mark in 669 aged human prefrontal cortices: in contrast to amyloid-β, tau protein burden had a broad effect on the epigenome, affecting 5,590 out of 26,384 H3K9Ac domains. Tau-related alterations aggregated in large genomic segments reflecting spatial chromatin organization, and the magnitude of these effects correlated with the segment’s nuclear lamina association. We confirmed the functional relevance of these chromatin changes by demonstrating (1) consistent transcriptional changes in three independent datasets and (2) similar findings in two AD mouse models. Finally, we found that tau overexpression in iPSC-derived neurons disrupted chromatin organization and that these effects could be blocked by a small molecule predicted to reverse the tau effect. Thus, we report large-scale tau-driven chromatin rearrangements in the aging human brain that may be reversible with HSP90 inhibitors.

scholarly journals Alzheimer’s-like pathology in aging rhesus macaques: Unique opportunity to study the etiology and treatment of Alzheimer’s disease

2019 ◽  
Vol 116 (52) ◽  
pp. 26230-26238 ◽  
Author(s):  
Amy F. T. Arnsten ◽  
Dibyadeep Datta ◽  
Shannon Leslie ◽  
Sheng-Tao Yang ◽  
Min Wang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Models ◽  
Immunoelectron Microscopy ◽  
Rhesus Monkeys ◽  
Early Stage ◽  
Amyloid Β ◽  
Tau Phosphorylation ◽  
Association Cortex ◽  
Tau Pathology

Although mouse models of Alzheimer’s disease (AD) have provided tremendous breakthroughs, the etiology of later onset AD remains unknown. In particular, tau pathology in the association cortex is poorly replicated in mouse models. Aging rhesus monkeys naturally develop cognitive deficits, amyloid plaques, and the same qualitative pattern and sequence of tau pathology as humans, with tangles in the oldest animals. Thus, aging rhesus monkeys can play a key role in AD research. For example, aging monkeys can help reveal how synapses in the prefrontal association cortex are uniquely regulated compared to the primary sensory cortex in ways that render them vulnerable to calcium dysregulation and tau phosphorylation, resulting in the selective localization of tau pathology observed in AD. The ability to assay early tau phosphorylation states and perform high-quality immunoelectron microscopy in monkeys is a great advantage, as one can capture early-stage degeneration as it naturally occurs in situ. Our immunoelectron microscopy studies show that phosphorylated tau can induce an “endosomal traffic jam” that drives amyloid precursor protein cleavage to amyloid-β in endosomes. As amyloid-β increases tau phosphorylation, this creates a vicious cycle where varied precipitating factors all lead to a similar phenotype. These data may help explain why circuits with aggressive tau pathology (e.g., entorhinal cortex) may degenerate prior to producing significant amyloid pathology. Aging monkeys therefore can play an important role in identifying and testing potential therapeutics to protect the association cortex, including preventive therapies that are challenging to test in humans.

scholarly journals Novel Alzheimer risk genes determine the microglia response to amyloid-β but not to TAU pathology

2018 ◽  
Author(s):  
Annerieke Sierksma ◽  
Ashley Lu ◽  
Evgenia Salta ◽  
Renzo Mancuso ◽  
Jesus Zoco ◽  
...  
Keyword(s):  
Mouse Models ◽  
Genetic Risk ◽  
Association Studies ◽  
Amyloid Β ◽  
Polygenic Risk Score ◽  
Genome Wide Association Studies ◽  
Tau Pathology ◽  
Data Set ◽  
Risk Genes ◽  
Genome Wide

AbstractBackgroundThousands of SNPs associated with risk of Alzheimer’s disease (AD) in genome-wide association studies (GWAS) do not reach genome-wide significance. When combined, they contribute however to a highly predictive polygenic risk score. The relevance of these subthreshold risk genes to disease, and how their combined predictive power translates into functionally relevant disease pathways, is unknown. We investigate here at the genome-wide level and in an unbiased way to what extent AD risk genes show altered gene expression in the context of increasing Aβ or Tau pathology in mouse models of AD.MethodsWe used an existing GWAS data set to generate lists of candidate AD genes at different levels of significance. We performed transcriptomic analysis on wild-type and transgenic APP/PS1 (APPtg) and Thy-TAU22 (TAUtg) mouse models at early and late stage of disease. We used unbiased weighted gene co-expression network analysis (WGCNA) to identify clusters of co-regulated genes responsive to Aβ or TAU pathology. Gene set enrichment was used to identify clusters that were enriched for AD risk genes.FindingsConsistent and significant enrichment of AD risk genes was found in only one out of 63 coexpression modules. This module is highly responsive to Aβ but not to TAU pathology. We identify in this module 18 AD risk genes (p-value=6·5e-11) including 11 new ones, GPC2, TREML2, SYK, GRN, SLC2A5, SAMSN1, PYDC1, HEXB, RRBP1, LYN and BLNK. All are expressed in microglia, have a binding site for the transcription factor SPI1 (PU.1), and become significantly upregulated when exposed to Aβ. A subset regulates FC-gamma receptor mediated phagocytosis.InterpretationGenetic risk of AD is functionally translated into a microglia pathway responsive to Aβ pathology. This insight integrates aspects of the amyloid hypothesis with genetic risk associated to sporadic AD.

scholarly journals A Closer Look into the Role of Protein Tau in the Identification of Promising Therapeutic Targets for Alzheimer’s Disease

2018 ◽  
Vol 8 (9) ◽  
pp. 162 ◽  
Author(s):  
Rubayat Islam Khan ◽  
Saif Nirzhor ◽  
Barnaly Rashid
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Progression ◽  
Tau Protein ◽  
Imaging Techniques ◽  
Memory Loss ◽  
Amyloid Β ◽  
Full Time ◽  
Tau Pathology ◽  
Severe Change

One of the most commonly known chronic neurodegenerative disorders, Alzheimer’s disease (AD), manifests the common type of dementia in 60–80% of cases. From a clinical standpoint, a patent cognitive decline and a severe change in personality, as caused by a loss of neurons, is usually evident in AD with about 50 million people affected in 2016. The disease progression in patients is distinguished by a gradual plummet in cognitive functions, eliciting symptoms such as memory loss, and eventually requiring full-time medical care. From a histopathological standpoint, the defining characteristics are intracellular aggregations of hyper-phosphorylated tau protein, known as neurofibrillary tangles (NFT), and depositions of amyloid β-peptides (Aβ) in the brain. The abnormal phosphorylation of tau protein is attributed to a wide gamut of neurological disorders known as tauopathies. In addition to the hyperphosphorylated tau lesions, neuroinflammatory processes could occur in a sustained manner through astro-glial activation, resulting in the disease progression. Recent findings have suggested a strong interplay between the mechanism of Tau phosphorylation, disruption of microtubules, and synaptic loss and pathology of AD. The mechanisms underlying these interactions along with their respective consequences in Tau pathology are still ill-defined. Thus, in this review: (1) we highlight the interplays existing between Tau pathology and AD; and (2) take a closer look into its role while identifying some promising therapeutic advances including state of the art imaging techniques.

scholarly journals Deep Learning for Alzheimer’s Disease: Mapping Large-scale Histological Tau Protein for Neuroimaging Biomarker Validation

2019 ◽  
Author(s):  
Maryana Alegro ◽  
Yuheng Chen ◽  
Dulce Ovando ◽  
Helmut Heinser ◽  
Rana Eser ◽  
...  
Keyword(s):  
Neural Network ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Brain ◽  
Tau Protein ◽  
Large Scale ◽  
Digital Pathology ◽  
Symptomatic Disease ◽  
Density Maps ◽  
Human Brains

AbstractDeposits of abnormal tau protein inclusions in the brain are a pathological hallmark of Alzheimer’s disease (AD), and are the best predictor of neuronal loss and clinical decline, but have been limited to postmortem assessment. Imaging-based biomarkers to detect tau deposits in vivo could leverage AD diagnosis and monitoring beginning in pre-symptomatic disease stages. Several PET tau tracers are available for research studies, but validation of such tracers against direct detection of tau deposits in brain tissue remains incomplete because of methodological limitations. Confirmation of the biological basis of PET binding requires large-scale voxel-to-voxel correlation has been challenging because of the dimensionality of the whole human brain histology data, deformation caused by tissue processing that precludes registration, and the need to process terabytes of information to cover the whole human brain volume at microscopic resolution. In this study, we created a computational pipeline for segmenting tau inclusions in billion-pixel digital pathology images of whole human brains, aiming at generating quantitative, tridimensional tau density maps that can be used to decipher the distribution of tau inclusions along AD progression and validate PET tau tracers. Our pipeline comprises several pre- and post-processing steps developed to handle the high complexity of these brain digital pathology images. SlideNet, a convolutional neural network designed to process our large datasets to locate and segment tau inclusions, is at the core of the pipeline. Using our novel method, we have successfully processed over 500 slides from two whole human brains, immunostained for two phospho-tau antibodies (AT100 and AT8) spanning several Gigabytes of images. Our artificial neural network estimated strong tau inclusion from image segmentation, which performs with ROC AUC of 0.89 and 0.85 for AT100 and AT8, respectively. Introspection studies further assessed the ability of our trained model to learn tau-related features. Furthermore, our pipeline successfully created 3D tau inclusion density maps that were co-registered to the histology 3D maps.

scholarly journals Microglia in Alzheimer’s Disease in the Context of Tau Pathology

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1439 ◽  
Author(s):  
Juan Ramón Perea ◽  
Marta Bolós ◽  
Jesús Avila
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Molecular Mechanisms ◽  
Senile Plaques ◽  
Protein A ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Tau Pathology ◽  
The Impact

Microglia are the cells that comprise the innate immune system in the brain. First described more than a century ago, these cells were initially assigned a secondary role in the central nervous system (CNS) with respect to the protagonists, neurons. However, the latest advances have revealed the complexity and importance of microglia in neurodegenerative conditions such as Alzheimer’s disease (AD), the most common form of dementia associated with aging. This pathology is characterized by the accumulation of amyloid-β peptide (Aβ), which forms senile plaques in the neocortex, as well as by the aggregation of hyperphosphorylated tau protein, a process that leads to the development of neurofibrillary tangles (NFTs). Over the past few years, efforts have been focused on studying the interaction between Aβ and microglia, together with the ability of the latter to decrease the levels of this peptide. Given that most clinical trials following this strategy have failed, current endeavors focus on deciphering the molecular mechanisms that trigger the tau-induced inflammatory response of microglia. In this review, we summarize the most recent studies on the physiological and pathological functions of tau protein and microglia. In addition, we analyze the impact of microglial AD-risk genes (APOE, TREM2, and CD33) in tau pathology, and we discuss the role of extracellular soluble tau in neuroinflammation.

scholarly journals Alzheimer's amyloid‐β and tau protein accumulation is associated with decreased expression of the LDL receptor‐associated protein in human brain tissue

2020 ◽  
Vol 10 (7) ◽  
Author(s):  
Claire E. Shepherd ◽  
Andrew J. Affleck ◽  
Anita Y. Bahar ◽  
Francine Carew‐Jones ◽  
Gillian Gregory ◽  
...  
Keyword(s):  
Human Brain ◽  
Brain Tissue ◽  
Tau Protein ◽  
Ldl Receptor ◽  
Amyloid Β ◽  
Protein Accumulation ◽  
Human Brain Tissue ◽  
Receptor Associated Protein

Resveratrol Rescues Tau-Induced Cognitive Deficits and Neuropathology in a Mouse Model of Tauopathy

2019 ◽  
Vol 16 (8) ◽  
pp. 710-722 ◽  
Author(s):  
Xiao-Ying Sun ◽  
Quan-Xiu Dong ◽  
Jie Zhu ◽  
Xun Sun ◽  
Li-Fan Zhang ◽  
...  
Keyword(s):  
Cognitive Deficits ◽  
Therapeutic Potential ◽  
Amyloid Β ◽  
Synaptic Proteins ◽  
Morris Water Maze Test ◽  
Phosphorylated Tau ◽  
Tau Pathology ◽  
Maze Test ◽  
N2a Cells ◽  
Tau Aggregation

Background: Alzheimer’s Disease (AD) is characterized by the presence of extracellular amyloid-β (Aβ) plaques and intraneuronal neurofibrillary tangles assembled by the microtubuleassociated protein tau. Increasing evidence demonstrated that tau pathology played an important role in AD progression. Resveratrol (RSV) has previously proved to exert neuroprotective effect against AD by inhibiting Aβ generation and Aβ-induced neurocytotoxicity, while its effect on tau pathology is still unknown. Method: The effect of RSV on tau aggregation was measured by Thioflavin T fluorescence and Transmission electron microscope imaging. The effect of RSV on tau oligomer-induced cytotoxicity was assessed by MTT assay and the uptake of extracellular tau by N2a cells was determined by immunocytochemistry. 6-month-old male PS19 mice were treated with RSV or vehicle by oral administration (gavage) once a day for 5 weeks. The cognitive performance was determined using Morris water maze test, object recognition test and Y-maze test. The levels of phosphorylated-tau, gliosis, proinflammatory cytokines such as TNF-α and IL-1β, and synaptic proteins including synaptophysin and PSD95 in the brains of the mice were evaluated by immunoblotting, immunostaining and ELISA, respectively. Results: RSV significantly inhibited tau aggregation and tau oligomer-induced cytotoxicity, and blocked the uptake of extracellular tau oligomers by N2a cells. When applied to PS19 mice, RSV treatment effectively rescued cognitive deficits, reducing the levels of phosphorylated tau, neuroinflammation and synapse loss in the brains of mice. Conclusion: These findings suggest that RSV has promising therapeutic potential for AD and other tauopathies.

Fundamental study on clarification of brain molecular pathology of Nasu-Hakola disease

Impact ◽  
2019 ◽  
Vol 2019 (8) ◽  
pp. 24-26
Author(s):  
Jun-ichi Satoh
Keyword(s):  
Multiple Sclerosis ◽  
Human Brain ◽  
Clinical Research ◽  
Neurodegenerative Diseases ◽  
Molecular Pathology ◽  
Large Scale ◽  
Molecular Pathogenesis ◽  
Novel Therapies ◽  
Brain Pathology ◽  
Fundamental Study

Brain pathology expert Dr Jun-ichi Satoh, from the Department of Bioinformatics and Molecular Neuropathology of Meiji Pharmaceutical University in Tokyo, is drawing on his expertise on neurology and neuroimmunology to delve into some of the more complex diseases impacting the human brain. His knowledge and expertise have allowed him to direct his research interests to study neurodegenerative diseases, such as Alzheimer's disease (AD), and neuroinflammatory diseases, such as multiple sclerosis (MS), and the analysis of their molecular pathogenesis by using a bioinformatics approach. His current focus is on Nasu-Hakola disease (NHD), a disease whose rarity has posed significant barriers towards performing large-scale clinical research in order to understand what exactly causes this disease and develop effective novel therapies.

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