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 ◽  
...  

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.

Author(s):  
Manon Bouchard ◽  
Oksana Suchowersky

Tauopathies are a group of disorders that have in common abnormal accumulation of tau protein in the brain. Although the different tauopathies have long been considered to be separate diseases, it is now clear that progressive supranuclear palsy, corticobasal degeneration and some forms of tau-positive frontotemporal lobar degeneration share clinical, pathological and genetic features. The important overlap between these disorders suggest they may represent different phenotypes of a single disease process, the clinical result depending on the topography of pathological lesions as well as other unknown factors.


2021 ◽  
Author(s):  
Xinyu Xiang ◽  
Tamta Arakhamia ◽  
Yari Carlomagno ◽  
Shikhar Dhingra ◽  
Manon Thierry ◽  
...  

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.


2010 ◽  
Vol 32 (2) ◽  
pp. 10-13
Author(s):  
Ceri Lyn-Adams ◽  
Kevin Moffat ◽  
Calum Sutherland ◽  
Bruno G. Frenguelli

Currently, there are 30 million people worldwide suffering from dementia. This number is predicted to rise to 100 million if effective treatments aren't developed rapidly. Alzheimer's disease (AD) is the most common form of dementia and is also the most prevalent of a group of neurodegenerative diseases known as tauopathies. Tauopathies are characterized by intraneuronal inclusions (pretangles) composed of aggregates of highly phosphorylated tau in the form of paired helical or straight filaments (PHFs), and neuronal loss. As the load of PHFs increases, they will aggregate and eventually form neurofibrillary tangles (NFTs) which fill the whole cell. The number of tau tangles present in the brain correlates well with the severity of dementia. Tau tangles are routinely found in AD, frontotemporal dementia linked to chromosome 17 with parkinsonism (FTDP-17), progressive supranuclear palsy, Pick's disease, corticobasal degeneration, head trauma and Down's syndrome to name but a few.


2021 ◽  
Author(s):  
Dandan Chu ◽  
Fei Liu

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.


2007 ◽  
Vol 10 (2) ◽  
pp. 3-14 ◽  
Author(s):  
M Ozansoy ◽  
A Başak

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.


2021 ◽  
Vol 271 ◽  
pp. 03037
Author(s):  
O Mikiko

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.


2017 ◽  
Author(s):  
Hee Kyung Park ◽  
Irene Litvan

Atypical parkinsonian disorders, which include two common proteinopathies, tauopathies and α-synucleinopathies, are clinically characterized by a progressive parkinsonism that typically does not respond to levodopa therapy and usually associates with early postural instability, falls, and other atypical features not observed in Parkinson disease. Tauopathies refer to neurodegenerative diseases in which there is an abnormal accumulation of hyperphosphorylated tau. The most frequent tauopathies are progressive supranuclear palsy and corticobasal degeneration. Better recognition of the expanding phenotypes of these disorders has led to the development of new diagnostic criteria. Furthermore, better knowledge about the pathogenesis (cell-to-cell transmission of pathologic tau) has resulted in advances in novel disease-modifying therapies that target tau. This review addresses the basic concepts of and recent issues in tauopathies, including their clinical phenotypes, genetic features, biomarkers, and novel experimental therapies.  Key words: atypical parkinsonian disorders, corticobasal degeneration, progressive supranuclear palsy, proteinopathies, tauopathies 


2021 ◽  
Author(s):  
Denglei Ma ◽  
Yanzheng Li ◽  
Yanqiu Zhu ◽  
Weipeng Wei ◽  
Li Zhang ◽  
...  

Abstract Background Aging is an important risk factor for sporadic Alzheimer’s disease (AD) and other neurodegenerative diseases. Senescence-accelerated mouse-prone 8 (SAMP8) is used as an animal model for brain aging and sporadic AD researches. The aim of the current study was to investigate the pharmacological effects of cornel iridoid glycoside (CIG), an active ingredient of Cornus officinalis, on AD-type pathological changes in young and aged SAMP8 mice. Methods Nissl and immunohistochemical staining was applied to detect NeuN-labeled neurons and myelin basic protein-labeled myelin sheath,. Western blotting was used to detect the expression levels of related proteins of synapse, APP processing and necroptosis. Results The results showed that SAMP8 mice at the age of 6 and 14 months exhibited age-related neuronal loss, demyelination, synaptic damage, and APP amyloidogenic processing. In addition, the increased levels of receptor-interacting protein kinase-1 (RIPK1), mixed lineage kinase domain-like protein (MLKL) and p-MLKL indicating necroptosis were found in the brain of SAMP8 mice. Intragastric administration of CIG for 2 months alleviated neuronal loss and demyelination, increased the expression of synaptophysin, postsynaptic density protein 95 and AMPA receptor subunit 1, elevated the levels of soluble APPα fragment and a disintegrin and metalloproteinase 10 (ADAM10), and decreased the levels of RIPK1, p-MLKL and MLKL in the brain of young and aged SAMP8 mice. Conclusion This study denoted that CIG might be a potential drug for aging-associated neurodegenerative diseases such as AD.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Denglei Ma ◽  
Yanzheng Li ◽  
Yanqiu Zhu ◽  
Weipeng Wei ◽  
Li Zhang ◽  
...  

Background. Aging is an important risk factor for sporadic Alzheimer’s disease (AD) and other neurodegenerative diseases. Senescence-accelerated mouse-prone 8 (SAMP8) is used as an animal model for brain aging and sporadic AD research studies. The aim of the current study was to investigate the pharmacological effects of cornel iridoid glycoside (CIG), an active ingredient of Cornus officinalis, on AD-type pathological changes in young and aged SAMP8 mice. Methods. Locomotor activity test was used to detect the aging process of SAMP8 mice. Nissl staining and immunohistochemical staining were applied to detect neurons and myelin basic protein-labelled myelin sheath. Western blotting was used to detect the expression levels of related proteins of synapse, APP processing, and necroptosis. Results. The results showed that SAMP8 mice at the age of 6 and 14 months exhibited lower locomotor activity, age-related neuronal loss, demyelination, synaptic damage, and APP amyloidogenic processing. In addition, the increased levels of receptor-interacting protein kinase-1 (RIPK1), mixed lineage kinase domain-like protein (MLKL), and p-MLKL indicating necroptosis were found in the brain of SAMP8 mice. Intragastric administration of CIG for 2 months improved locomotor activity; alleviated neuronal loss and demyelination; increased the expression of synaptophysin, postsynaptic density protein 95, and AMPA receptor subunit 1; elevated the levels of soluble APPα fragment and disintegrin and metalloproteinase 10 (ADAM10); and decreased the levels of RIPK1, p-MLKL, and MLKL in the brain of young and aged SAMP8 mice. Conclusion. This study denoted that CIG might be a potential drug for aging-related neurodegenerative diseases such as AD.


Author(s):  
Natalie Swerdlow ◽  
Heather Wilkins

Stress mechanisms have long been associated with neuronal loss and neurodegenerative diseases. The origin of cell stress and neuronal loss likely stems from multiple pathways. These include (but are not limited to) bioenergetic failure, neuroinflammation, and loss of proteostasis. Cells have adapted compensatory mechanisms to overcome stress and circumvent death. One mechanism is mitophagy. Recent studies have implicated mitophagy in several neurodegenerative diseases and clinical trials are underway which target mitophagy pathways. Here, we review mitophagy pathways, the role of mitophagy in neurodegeneration, potential therapeutics, and the need for further study.


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