scholarly journals Role of molecular polymorphism in defining tau filament structures in neurodegenerative diseases

2021 ◽  
Author(s):  
Xinyu Xiang ◽  
Tamta Arakhamia ◽  
Yari Carlomagno ◽  
Shikhar Dhingra ◽  
Manon Thierry ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Molecular Level ◽  
Corticobasal Degeneration ◽  
Molecular Polymorphism ◽  
Cofactor Binding ◽  
Tau Isoforms ◽  
The Brain ◽  
Disease Specific

Misfolding and aggregation of tau protein is implicated in many neurodegenerative diseases that are typified by the presence of large, filamentous tau inclusions. The aggregation of tau in human brain is disease-specific with characteristic filaments defining the neuropathology. An understanding of how identical tau isoforms aggregate into disparate filament morphologies in phenotypically distinct tau-related diseases remains elusive. Here, we determine the structure of a brain-derived twisted tau filament in progressive supranuclear palsy and compare it to a dissimilar tau fold found in corticobasal degeneration. While the tau filament core in both diseases is comprised of residues 274 to 380, molecular-level polymorphism exists. Potential origins of the molecular polymorphism, such as noncovalent cofactor binding, are identified and predicted to modulate tau filament structures in the brain.

scholarly journals Tau in Health and Neurodegenerative Diseases

2021 ◽  
Author(s):  
Dandan Chu ◽  
Fei Liu
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Dynamic Properties ◽  
Corticobasal Degeneration ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
Argyrophilic Grain ◽  
The Brain ◽  
Filamentous Inclusions

Tau, one of the major microtubule-associated proteins, modulates the dynamic properties of microtubules in the mammalian nervous system. Tau is abundantly expressed in the brain, particularly in the hippocampus. Insoluble and filamentous inclusions of tau in neurons or glia are discovered in neurodegenerative diseases termed ‘tauopathies’, including Alzheimer’s disease (AD), argyrophilic grain disease (AGD), corticobasal degeneration (CBD), frontotemporal dementia (FTD), Pick’s disease (PiD) and progressive supranuclear palsy (PSP). Accumulation of intracellular neurofibrillary tangles (NFTs), which are composed of hyperphosphorylated tau, is directly correlated with the degree of Alzheimer\'s dementia. This chapter reviews the role of tau protein in physiological conditions and the pathological changes of tau related to neurodegenerative diseases. The applications of tau as a therapeutic target are also discussed.

scholarly journals Mechanisms of Neurodegeneration in Various Forms of Parkinsonism—Similarities and Differences

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 656
Author(s):  
Dariusz Koziorowski ◽  
Monika Figura ◽  
Łukasz M. Milanowski ◽  
Stanisław Szlufik ◽  
Piotr Alster ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Protein Gene ◽  
Clinical Presentation ◽  
Neuronal Loss ◽  
Corticobasal Degeneration ◽  
Inflammatory Factors ◽  
Parkinsonian Disorders ◽  
Genetic Features ◽  
The Brain

Parkinson's disease (PD), dementia with Lewy body (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA) belong to a group of neurodegenerative diseases called parkinsonian syndromes. They share several clinical, neuropathological and genetic features. Neurodegenerative diseases are characterized by the progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra- and intracellular accumulation of misfolded proteins. The parkinsonian diseases affect distinct areas of the brain. PD and MSA belong to a group of synucleinopathies that are characterized by the presence of fibrillary aggregates of α-synuclein protein in the cytoplasm of selected populations of neurons and glial cells. PSP is a tauopathy associated with the pathological aggregation of the microtubule associated tau protein. Although PD is common in the world's aging population and has been extensively studied, the exact mechanisms of the neurodegeneration are still not fully understood. Growing evidence indicates that parkinsonian disorders to some extent share a genetic background, with two key components identified so far: the microtubule associated tau protein gene (MAPT) and the α-synuclein gene (SNCA). The main pathways of parkinsonian neurodegeneration described in the literature are the protein and mitochondrial pathways. The factors that lead to neurodegeneration are primarily environmental toxins, inflammatory factors, oxidative stress and traumatic brain injury.

scholarly journals Factors of Cell Degeneration or Death caused by Mutant Tau Protein

2021 ◽  
Vol 271 ◽  
pp. 03037
Author(s):  
O Mikiko
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Protein Expression Level ◽  
Cell Degeneration ◽  
Pathological Conditions ◽  
Type Gene ◽  
And Function ◽  
Protein Dysfunction ◽  
The Brain

Tau protein is a microtubule associated protein mainly expressed in neurons. Under pathological conditions, Tau protein is abnormally hyperphosphorylated and separated from microtubules. Abnormal Tau aggregates form nerve fiber tangles, which are insoluble aggregates in the brain. It is due to the microtubule rupture caused by Tau protein dysfunction and it is associated with neurofibrillar degeneration in Alzheimer's disease.This paper studies several reports and research on the structure and function of Tau protein, the role of Tau protein in pathological diseases and its relationship with neurodegenerative diseases. This paper concludes that Tau protein has undergone abnormal modification and aggregation in many neurodegenerative diseases, but the specific type of Tau protein that causes neurotoxicity, as well as the pathogenesis of its phosphorylation and functional injury inducing nerve apoptosis, are still not fully understood. Various abnormal modifications of Tau protein occur under pathological conditions, and fatal cascade events occur at different stages of neuron apoptosis. Therefore, the causes and effects of cytotoxicity mediated by Tau protein are very complicated. Different or even opposite conclusions are sometimes drawn in Tau protein-mediated neurodegeneration studies. This may be due to differences in Tau protein type, gene mutation and protein expression level.

scholarly journals Co-factor-free aggregation of tau into seeding-competent RNA-sequestering amyloid fibrils

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pijush Chakraborty ◽  
Gwladys Rivière ◽  
Shu Liu ◽  
Alain Ibáñez de Opakua ◽  
Rıza Dervişoğlu ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Corticobasal Degeneration ◽  
Binding Studies ◽  
Rigid Core ◽  
Tau Aggregation ◽  
The Brain ◽  
Tau Aggregate ◽  
Disease Specific ◽  
Tau Fibrils

AbstractPathological aggregation of the protein tau into insoluble aggregates is a hallmark of neurodegenerative diseases. The emergence of disease-specific tau aggregate structures termed tau strains, however, remains elusive. Here we show that full-length tau protein can be aggregated in the absence of co-factors into seeding-competent amyloid fibrils that sequester RNA. Using a combination of solid-state NMR spectroscopy and biochemical experiments we demonstrate that the co-factor-free amyloid fibrils of tau have a rigid core that is similar in size and location to the rigid core of tau fibrils purified from the brain of patients with corticobasal degeneration. In addition, we demonstrate that the N-terminal 30 residues of tau are immobilized during fibril formation, in agreement with the presence of an N-terminal epitope that is specifically detected by antibodies in pathological tau. Experiments in vitro and in biosensor cells further established that co-factor-free tau fibrils efficiently seed tau aggregation, while binding studies with different RNAs show that the co-factor-free tau fibrils strongly sequester RNA. Taken together the study provides a critical advance to reveal the molecular factors that guide aggregation towards disease-specific tau strains.

scholarly journals News about the Role of Fluid and Imaging Biomarkers in Neurodegenerative Diseases

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 252
Author(s):  
Jacopo Meldolesi
Keyword(s):  
Neurodegenerative Diseases ◽  
Imaging Techniques ◽  
Imaging Biomarkers ◽  
Positron Emission ◽  
Specific Proteins ◽  
Great Relevance ◽  
The Brain ◽  
Positive Point

Biomarkers are molecules that are variable in their origin, nature, and mechanism of action; they are of great relevance in biology and also in medicine because of their specific connection with a single or several diseases. Biomarkers are of two types, which in some cases are operative with each other. Fluid biomarkers, started around 2000, are generated in fluid from specific proteins/peptides and miRNAs accumulated within two extracellular fluids, either the central spinal fluid or blood plasma. The switch of these proteins/peptides and miRNAs, from free to segregated within extracellular vesicles, has induced certain advantages including higher levels within fluids and lower operative expenses. Imaging biomarkers, started around 2004, are identified in vivo upon their binding by radiolabeled molecules subsequently revealed in the brain by positron emission tomography and/or other imaging techniques. A positive point for the latter approach is the quantitation of results, but expenses are much higher. At present, both types of biomarker are being extensively employed to study Alzheimer’s and other neurodegenerative diseases, investigated from the presymptomatic to mature stages. In conclusion, biomarkers have revolutionized scientific and medical research and practice. Diagnosis, which is often inadequate when based on medical criteria only, has been recently improved by the multiplicity and specificity of biomarkers. Analogous results have been obtained for prognosis. In contrast, improvement of therapy has been limited or fully absent, especially for Alzheimer’s in which progress has been inadequate. An urgent need at hand is therefore the progress of a new drug trial design together with patient management in clinical practice.

scholarly journals The Role of Long Noncoding RNAs in Diabetic Alzheimer’s Disease

2018 ◽  
Vol 7 (11) ◽  
pp. 461 ◽  
Author(s):  
Young-Kook Kim ◽  
Juhyun Song
Keyword(s):  
Alzheimer’S Disease ◽  
Insulin Resistance ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Noncoding Rnas ◽  
Long Noncoding Rnas ◽  
Glucose Dysregulation ◽  
Near Future ◽  
The Brain

Long noncoding RNAs (lncRNAs) are involved in diverse physiological and pathological processes by modulating gene expression. They have been found to be dysregulated in the brain and cerebrospinal fluid of patients with neurodegenerative diseases, and are considered promising therapeutic targets for treatment. Among the various neurodegenerative diseases, diabetic Alzheimer’s disease (AD) has been recently emerging as an important issue due to several unexpected reports suggesting that metabolic issues in the brain, such as insulin resistance and glucose dysregulation, could be important risk factors for AD. To facilitate understanding of the role of lncRNAs in this field, here we review recent studies on lncRNAs in AD and diabetes, and summarize them with different categories associated with the pathogenesis of the diseases including neurogenesis, synaptic dysfunction, amyloid beta accumulation, neuroinflammation, insulin resistance, and glucose dysregulation. It is essential to understand the role of lncRNAs in the pathogenesis of diabetic AD from various perspectives for therapeutic utilization of lncRNAs in the near future.

scholarly journals Tauopathies: A Distinct Class of Neurodegenerative Diseases

2007 ◽  
Vol 10 (2) ◽  
pp. 3-14 ◽  
Author(s):  
M Ozansoy ◽  
A Başak
Keyword(s):  
Neurodegenerative Diseases ◽  
Neurofibrillary Tangles ◽  
Neuronal Loss ◽  
Corticobasal Degeneration ◽  
Chromosome 17 ◽  
Cell Degeneration ◽  
Distinct Class ◽  
Postencephalitic Parkinsonism ◽  
Tau Isoforms ◽  
Niemann Pick

Tauopathies: A Distinct Class of Neurodegenerative DiseasesNeurodegenerative diseases are characterized by neuronal loss and intraneuronal accumulation of fibrillary materials, of which, neurofibrillary tangles (NFT) are the most common. Neurofibrillary tangles also occur in normal aging and contain the hyperphosphorylated microtubule-associated protein tau. A detailed presentation is made of the molecular bases of Alzheimer's disease (AD), postencephalitic parkinsonism, amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of Guam, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick's disease, frontotemporal dementia (FTD), Down's syndrome, myotonic dystrophy (DM) and Niemann-Pick Type C (NPC) disease, which are considered to be common tauopathies. The unique human tau gene extends over 100 kb of the long arm of chromosome 17 and contains 16 exons. The human brain contains six tau isoforms that contain from 352 to 441 amino acids. To date, 34 pathogenic tau mutations have been described among 101 families affected by FTD with parkinsonism linked to chromosome 17 (FTDP-17). These mutations may involve alternative splicing of exon 10 that lead to changes in the proportion of 4-repeat- and 3-repeat-tau isoforms, or may modify tau interactions with microtubules. Tau aggregates differ in degree of phosphorylation and in content of tau isoforms. Five classes of tauopathies have been defined depending on the type of tau aggregates. The key event in tauopathies is the disorganization of the cytoskeleton, which is based on mutations/polymorphisms in the tau gene and lead to nerve cell degeneration. In this review, tauopathies as a distinct class of neurodegenerative diseases are discussed with emphasis on their molecular pathology and genetics.

ATP-binding cassette transporters and neurodegenerative diseases

2021 ◽  
Author(s):  
Jared S. Katzeff ◽  
Woojin Scott Kim
Keyword(s):  
Neurodegenerative Diseases ◽  
Abc Transporters ◽  
Brain Diseases ◽  
Atp Binding ◽  
Future Directions ◽  
Diverse Range ◽  
The Brain ◽  
Lateral Sclerosis ◽  
Atp Binding Cassette

Abstract ATP-binding cassette (ABC) transporters are one of the largest groups of transporter families in humans. ABC transporters mediate the translocation of a diverse range of substrates across cellular membranes, including amino acids, nucleosides, lipids, sugars and xenobiotics. Neurodegenerative diseases are a group of brain diseases that detrimentally affect neurons and other brain cells and are usually associated with deposits of pathogenic proteins in the brain. Major neurodegenerative diseases include Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. ABC transporters are highly expressed in the brain and have been implicated in a number of pathological processes underlying neurodegenerative diseases. This review outlines the current understanding of the role of ABC transporters in neurodegenerative diseases, focusing on some of the most important pathways, and also suggests future directions for research in this field.

scholarly journals Activate or Inhibit? Implications of Autophagy Modulation as a Therapeutic Strategy for Alzheimer’s Disease

2020 ◽  
Vol 21 (18) ◽  
pp. 6739
Author(s):  
Sharmeelavathi Krishnan ◽  
Yasaswi Shrestha ◽  
Dona P. W. Jayatunga ◽  
Sarah Rea ◽  
Ralph Martins ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Therapeutic Strategy ◽  
Senile Plaques ◽  
Physiological State ◽  
Proteotoxic Stress ◽  
Underlying Causes ◽  
The Brain

Neurodegenerative diseases result in a range of conditions depending on the type of proteinopathy, genes affected or the location of the degeneration in the brain. Proteinopathies such as senile plaques and neurofibrillary tangles in the brain are prominent features of Alzheimer’s disease (AD). Autophagy is a highly regulated mechanism of eliminating dysfunctional organelles and proteins, and plays an important role in removing these pathogenic intracellular protein aggregates, not only in AD, but also in other neurodegenerative diseases. Activating autophagy is gaining interest as a potential therapeutic strategy for chronic diseases featuring protein aggregation and misfolding, including AD. Although autophagy activation is a promising intervention, over-activation of autophagy in neurodegenerative diseases that display impaired lysosomal clearance may accelerate pathology, suggesting that the success of any autophagy-based intervention is dependent on lysosomal clearance being functional. Additionally, the effects of autophagy activation may vary significantly depending on the physiological state of the cell, especially during proteotoxic stress and ageing. Growing evidence seems to favour a strategy of enhancing the efficacy of autophagy by preventing or reversing the impairments of the specific processes that are disrupted. Therefore, it is essential to understand the underlying causes of the autophagy defect in different neurodegenerative diseases to explore possible therapeutic approaches. This review will focus on the role of autophagy during stress and ageing, consequences that are linked to its activation and caveats in modulating this pathway as a treatment.

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