scholarly journals Tau-mediated synaptic damage in Alzheimer’s disease

2015 ◽  
Vol 6 (1) ◽  
pp. 214-226 ◽  
Author(s):  
Santosh Jadhav ◽  
Veronika Cubinkova ◽  
Ivana Zimova ◽  
Veronika Brezovakova ◽  
Aladar Madari ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Regional Distribution ◽  
Large Body ◽  
Tau Proteins ◽  
Neurofibrillary Pathology ◽  
Synaptic Loss ◽  
Protein Tau ◽  
The Brain

AbstractSynapses are the principal sites for chemical communication between neurons and are essential for performing the dynamic functions of the brain. In Alzheimer’s disease and related tauopathies, synapses are exposed to disease modified protein tau, which may cause the loss of synaptic contacts that culminate in dementia. In recent decades, structural, transcriptomic and proteomic studies suggest that Alzheimer’s disease represents a synaptic disorder. Tau neurofibrillary pathology and synaptic loss correlate well with cognitive impairment in these disorders. Moreover, regional distribution and the load of neurofibrillary lesions parallel the distribution of the synaptic loss. Several transgenic models of tauopathy expressing various forms of tau protein exhibit structural synaptic deficits. The pathological tau proteins cause the dysregulation of synaptic proteome and lead to the functional abnormalities of synaptic transmission. A large body of evidence suggests that tau protein plays a key role in the synaptic impairment of human tauopathies.

scholarly journals Braiding Braak and Braak: Staging patterns and model selection in network neurodegeneration

2021 ◽  
Author(s):  
Prama Putra ◽  
Travis Thompson ◽  
Alain Goriely
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Tau Proteins ◽  
Histopathological Analysis ◽  
Braak Staging ◽  
New Methods ◽  
Tau Aggregation ◽  
The Brain ◽  
And Diffusion

AbstractA hallmark of Alzheimer’s disease is the aggregation of insoluble amyloid-beta plaques and tau protein neurofibrillary tangles. A key histopathological observation is that tau protein aggregates follow a clear progression pattern through the brain; characterized by six distinct stages. This so-called ‘Braak staging pattern’ has become the gold standard for Alzheimer’s disease progression. It has also been suggested, via a histopathological analysis, that soluble seed-competent tau seeding precedes tau aggregation in the same manner. Mathematical models such as prion-like propagation on networks have the ability to capture key feature of the dynamics. Here, we study the staging of tau proteins using a model of proteopathy that include both local growth due to autocatalytic effects and diffusion along axonal pathways. We develop new methods to capture the staging patterns and use these as a qualitative criterion to identify the best model for diffusion process on networks and to identify possible parameter regimes. Our analysis provides a systematic way to study Braak staging in neurodegenerative processes.

scholarly journals Protein-protein interactions in neurodegenerative diseases: a conspiracy theory

2020 ◽  
Author(s):  
Travis B. Thompson ◽  
Pavanjit Chaggar ◽  
Ellen Kuhl ◽  
Alain Goriely ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disease ◽  
Amyloid Beta ◽  
Tau Protein ◽  
Conspiracy Theory ◽  
Tau Proteins ◽  
Disease Research ◽  
Protein Clearance ◽  
The Brain

AbstractNeurodegenerative diseases such as Alzheimer’s or Parkinson’s are associated with the prion-like propagation and aggregation of toxic proteins. A long standing hypothesis that amyloid-beta drives Alzheimer’s disease has proven the subject of contemporary controversy; leading to new research in both the role of tau protein and its interaction with amyloid-beta. Conversely, recent work in mathematical modeling has demonstrated the relevance of nonlinear reaction-diffusion type equations to capture essential features of the disease. Such approaches have been further simplified, to network-based models, and offer researchers a powerful set of computationally tractable tools with which to investigate neurodegenerative disease dynamics.Here, we propose a novel, coupled network-based model for a two-protein system that includes an enzymatic interaction term alongside a simple model of aggregate transneuronal damage. We apply this theoretical model to test the possible interactions between tau proteins and amyloid-beta and study the resulting coupled behavior between toxic protein clearance and proteopathic phenomenology. Our analysis reveals ways in which amyloid-beta and tau proteins may conspire with each other to enhance the nucleation and propagation of different diseases, thus shedding new light on the importance of protein clearance and protein interaction mechanisms in prion-like models of neurodegenerative disease.Author SummaryIn 1906 Dr. Alois Alzheimer delivered a lecture to the Society of Southwest German Psychiatrists. Dr. Alzheimer presented the case of Ms. Auguste Deter; her symptoms would help to define Alzheimer’s disease (AD). Over a century later, with an aging world population, AD is at the fore of global neurodegenerative disease research. Previously, toxic amyloid-beta protein (Aβ) was thought to be the primary driver of AD development. Recent research suggests that another protein, tau, plays a fundamental role. Toxic tau protein contributes to cognitive decline and appears to interact with toxic Aβ; research suggests that toxic Aβ may further increase the effects of toxic tau.Theoretical mathematical models are an important part of neurodegenerative disease research. Such models: enable extensible computational exploration; illuminate emergent behavior; and reduce research costs. We have developed a novel, theoretical mathematical model of two interacting species of proteins within the brain. We analyze the mathematical model and demonstrate a computational implementation in the context of Aβ-tau interaction in the brain. Our model clearly suggests that: the removal rate of toxic protein plays a critical role in AD; and the Aβ-tau ‘conspiracy theory’ is a nuanced, and exciting path forward for Alzheimer’s disease research.

AADVAC1, AN ACTIVE IMMUNOTHERAPY FOR ALZHEIMER’S DISEASE AND NON ALZHEIMER TAUOPATHIES: AN OVERVIEW OF PRECLINICAL AND CLINICAL DEVELOPMENT

2018 ◽  
pp. 1-7
Author(s):  
P. Novak ◽  
N. Zilka ◽  
M. Zilkova ◽  
B. Kovacech ◽  
R. Skrabana ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Neurodegenerative Disorder ◽  
Therapeutic Potential ◽  
Phase 1 ◽  
Primary Progressive Aphasia ◽  
Tau Proteins ◽  
Active Immunotherapy ◽  
Tau Pathology

Neurofibrillary tau protein pathology is closely associated with the progression and phenotype of cognitive decline in Alzheimer’s disease and other tauopathies, and a high-priority target for disease-modifying therapies. Herein, we provide an overview of the development of AADvac1, an active immunotherapy against tau pathology, and tau epitopes that are potential targets for immunotherapy. The vaccine leads to the production of antibodies that target conformational epitopes in the microtubule-binding region of tau, with the aim to prevent tau aggregation and spreading of pathology, and promote tau clearance. The therapeutic potential of the vaccine was evaluated in transgenic rats and mice expressing truncated, non mutant tau protein, which faithfully replicate of human tau pathology. Treatment with AADvac1 resulted in reduction of neurofibrillary pathology and insoluble tau in their brains, and amelioration of their deleterious phenotype. The vaccine was highly immunogenic in humans, inducing production of IgG antibodies against the tau peptide in 29/30 treated elderly patients with mild-to-moderate Alzheimer’s. These antibodies were able to recognise insoluble tau proteins in Alzheimer patients’ brains. Treatment with AADvac1 proved to be remarkably safe, with injection site reactions being the only adverse event tied to treatment. AADvac1 is currently being investigated in a phase 2 study in Alzheimer’s disease, and a phase 1 study in non-fluent primary progressive aphasia, a neurodegenerative disorder with a high tau pathology component.

scholarly journals Therapeutic potential of astaxanthin and superoxide dismutase in Alzheimer's disease

Open Biology ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 210013
Author(s):  
Vyshnavy Balendra ◽  
Sandeep Kumar Singh
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Superoxide Dismutase ◽  
Antioxidant System ◽  
Tau Protein ◽  
Therapeutic Potential ◽  
Plaque Burden ◽  
Memory Decline ◽  
Endogenous Antioxidants ◽  
The Brain

Oxidative stress, the imbalance of the antioxidant system, results in an accumulation of neurotoxic proteins in Alzheimer's disease (AD). The antioxidant system is composed of exogenous and endogenous antioxidants to maintain homeostasis. Superoxide dismutase (SOD) is an endogenous enzymatic antioxidant that converts superoxide ions to hydrogen peroxide in cells. SOD supplementation in mice prevented cognitive decline in stress-induced cells by reducing lipid peroxidation and maintaining neurogenesis in the hippocampus. Furthermore, SOD decreased expression of BACE1 while reducing plaque burden in the brain. Additionally, Astaxanthin (AST), a potent exogenous carotenoid, scavenges superoxide anion radicals. Mice treated with AST showed slower memory decline and decreased depositions of amyloid-beta (A β ) and tau protein. Currently, the neuroprotective potential of these supplements has only been examined separately in studies. However, a single antioxidant cannot sufficiently resist oxidative damage to the brain, therefore, a combinatory approach is proposed as a relevant therapy for ameliorating pathological changes in AD.

scholarly journals Microglia-Based Sex-Biased Neuropathology in Early-Stage Alzheimer’s Disease Model Mice and the Potential Pharmacologic Efficacy of Dioscin

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3261
Author(s):  
Xiao Liu ◽  
Qian Zhou ◽  
Jia-He Zhang ◽  
Xiaoying Wang ◽  
Xiumei Gao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Stage ◽  
Disease Model ◽  
Amyloid Β ◽  
Brain Lesions ◽  
Synaptic Dysfunction ◽  
Synaptic Loss ◽  
And Function ◽  
The Brain

Alzheimer’s disease (AD), the most common form of dementia, is characterized by amyloid-β (Aβ) accumulation, microglia-associated neuroinflammation, and synaptic loss. The detailed neuropathologic characteristics in early-stage AD, however, are largely unclear. We evaluated the pathologic brain alterations in young adult App knock-in model AppNL-G-F mice at 3 and 6 months of age, which corresponds to early-stage AD. At 3 months of age, microglia expression in the cortex and hippocampus was significantly decreased. By the age of 6 months, the number and function of the microglia increased, accompanied by progressive amyloid-β deposition, synaptic dysfunction, neuroinflammation, and dysregulation of β-catenin and NF-κB signaling pathways. The neuropathologic changes were more severe in female mice than in male mice. Oral administration of dioscin, a natural product, ameliorated the neuropathologic alterations in young AppNL-G-F mice. Our findings revealed microglia-based sex-differential neuropathologic changes in a mouse model of early-stage AD and therapeutic efficacy of dioscin on the brain lesions. Dioscin may represent a potential treatment for AD.

scholarly journals Regulation of brain insulin signaling: A new function for tau

2017 ◽  
Vol 214 (8) ◽  
pp. 2171-2173 ◽  
Author(s):  
Maud Gratuze ◽  
Emmanuel Planel
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Insulin Signaling ◽  
Loss Of Function ◽  
Brain Insulin ◽  
The Brain

In this issue of JEM, Marciniak et al. (https://doi.org/10.1084/jem.20161731) identify a putative novel function of tau protein as a regulator of insulin signaling in the brain. They find that tau deletion impairs hippocampal response to insulin through IRS-1 and PTEN dysregulation and suggest that, in Alzheimer’s disease, impairment of brain insulin signaling might occur via tau loss of function.

scholarly journals The Many Faces of Post-Ischemic Tau Protein in Brain Neurodegeneration of the Alzheimer’s Disease Type

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2213
Author(s):  
Ryszard Pluta ◽  
Stanisław J. Czuczwar ◽  
Sławomir Januszewski ◽  
Mirosław Jabłoński
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Injury ◽  
Cerebral Ischemia ◽  
Tau Protein ◽  
Ischemia Reperfusion ◽  
Disease Type ◽  
Dependent Manner ◽  
Ischemic Brain ◽  
The Brain

Recent data suggest that post-ischemic brain neurodegeneration in humans and animals is associated with the modified tau protein in a manner typical of Alzheimer’s disease neuropathology. Pathological changes in the tau protein, at the gene and protein level due to cerebral ischemia, can lead to the development of Alzheimer’s disease-type neuropathology and dementia. Some studies have shown increased tau protein staining and gene expression in neurons following ischemia-reperfusion brain injury. Recent studies have found the tau protein to be associated with oxidative stress, apoptosis, autophagy, excitotoxicity, neuroinflammation, blood-brain barrier permeability, mitochondrial dysfunction, and impaired neuronal function. In this review, we discuss the interrelationship of these phenomena with post-ischemic changes in the tau protein in the brain. The tau protein may be at the intersection of many pathological mechanisms due to severe neuropathological changes in the brain following ischemia. The data indicate that an episode of cerebral ischemia activates the damage and death of neurons in the hippocampus in a tau protein-dependent manner, thus determining a novel and important mechanism for the survival and/or death of neuronal cells following ischemia. In this review, we update our understanding of proteomic and genomic changes in the tau protein in post-ischemic brain injury and present the relationship between the modified tau protein and post-ischemic neuropathology and present a positive correlation between the modified tau protein and a post-ischemic neuropathology that has characteristics of Alzheimer’s disease-type neurodegeneration.

scholarly journals Editorial for the Genetics of Alzheimer’s Disease Special Issue: October 2021

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1794
Author(s):  
Laura Ibanez ◽  
Justin B. Miller
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gray Matter ◽  
Neuronal Death ◽  
Tau Proteins ◽  
Special Issue ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain

Alzheimer’s disease is a complex and multifactorial condition regulated by both genetics and lifestyle, which ultimately results in the accumulation of β-amyloid (Aβ) and tau proteins in the brain, loss of gray matter, and neuronal death [...]

scholarly journals Effect of Vitamin D Supplementation on the Progression of Alzheimer’s Disease in Rats: A Mechanistic Approach

2021 ◽  
Author(s):  
Parmi Patel ◽  
Jigna Samir Shah
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Vitamin D ◽  
Vitamin D Supplementation ◽  
Cognitive Status ◽  
Tau Proteins ◽  
Biochemical Alterations ◽  
Vitamin D Levels ◽  
The Brain

Abstract Purpose: A multifaceted treatment approach can be effective for Alzheimer's disease (AD). However, currently, it involves only symptomatic treatment with cholinergic drugs. Beneficial effects of high vitamin D levels or its intake in the prevention and treatment of cognitive disorders have been reported. Thus, the present study examined the preventive effect of vitamin D supplementation on AD progression and evaluated its impact on the accumulation or degradation of Aβ plaques. Methods: A single intraperitoneal injection of scopolamine was used to induce AD in rats. Treatment of vitamin D was provided for 21 days after the injection. Various behavioral parameters like learning, spatial memory and exploratory behavior, biochemical alterations in the brain homogenate and histology of the hippocampus were investigated. Results: Our results indicated that scopolamine-induced rats depicted cognitive deficits with high Aβ levels and hyperphosphorylated tau proteins in the brain tissue, while vitamin D supplementation could significantly improve the cognitive status and lower these protein levels. These results were supported by the histopathological and immunohistochemical staining of the hippocampal brain region. Furthermore, mechanistic analysis depicted that vitamin D supplementation improved the Aβ protein clearance by increasing the neprilysin levels. It also reduced the accumulation of Aβ plaques by lowering neuroinflammation as well as oxidative stress. Conclusion: The present findings indicate that vitamin D supplementation can delay AD progression by an increase in Aβ plaques degradation or reducing inflammation and oxidative stress.

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