scholarly journals Enhancing microtubule stabilization rescues cognitive deficits and ameliorates pathological phenotype in an amyloidogenic Alzheimer’s disease model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Juan Jose Fernandez-Valenzuela ◽  
Raquel Sanchez-Varo ◽  
Clara Muñoz-Castro ◽  
Vanessa De Castro ◽  
Elisabeth Sanchez-Mejias ◽  
...  

Abstract In Alzheimer’s disease (AD), and other tauopathies, microtubule destabilization compromises axonal and synaptic integrity contributing to neurodegeneration. These diseases are characterized by the intracellular accumulation of hyperphosphorylated tau leading to neurofibrillary pathology. AD brains also accumulate amyloid-beta (Aβ) deposits. However, the effect of microtubule stabilizing agents on Aβ pathology has not been assessed so far. Here we have evaluated the impact of the brain-penetrant microtubule-stabilizing agent Epothilone D (EpoD) in an amyloidogenic model of AD. Three-month-old APP/PS1 mice, before the pathology onset, were weekly injected with EpoD for 3 months. Treated mice showed significant decrease in the phospho-tau levels and, more interesting, in the intracellular and extracellular hippocampal Aβ accumulation, including the soluble oligomeric forms. Moreover, a significant cognitive improvement and amelioration of the synaptic and neuritic pathology was found. Remarkably, EpoD exerted a neuroprotective effect on SOM-interneurons, a highly AD-vulnerable GABAergic subpopulation. Therefore, our results suggested that EpoD improved microtubule dynamics and axonal transport in an AD-like context, reducing tau and Aβ levels and promoting neuronal and cognitive protection. These results underline the existence of a crosstalk between cytoskeleton pathology and the two major AD protein lesions. Therefore, microtubule stabilizers could be considered therapeutic agents to slow the progression of both tau and Aβ pathology.

2020 ◽  
Author(s):  
Mardani Abdul Halim ◽  
Izzah Madihah Rosli ◽  
Siti Shafika Muhamad Jaafar ◽  
Hoi-Min Ooi ◽  
Pui-Wei Leong ◽  
...  

AbstractAlzheimer’s disease is a complex neurodegenerative disease and is only unique to human. The disease is defined in human brain by the accumulation of amyloid beta in the parenchyma of the brain. Withania somnifera, commonly known as Ashwagandha is an Indian Ayurvedic medicine that has been used for centuries to treat countless range of human health problem. The active compound of Ashwagandha was shown to be beneficial in treating many neurodegenerative diseases including Alzheimer’s disease (AD). In this study, Drosophila melanogaster AD model was used to study the effect of Ashwagandha on the toxicity of beta amyloid and also the longevity effect of the compound. We found that 20 mg/mL of Ashwagandha was shown to be effective in rescuing the “rough eye phenotype” of AD Drosophila. Furthermore, Ashwagandha also promotes longevity in AD as well as wild-type Drosophila. The results above showed that Ashwagandha could potentially be a potent drug to treat AD as well as maintaining the wellbeing of cells.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna A. Lauer ◽  
Daniel Janitschke ◽  
Malena dos Santos Guilherme ◽  
Vu Thu Thuy Nguyen ◽  
Cornel M. Bachmann ◽  
...  

AbstractAlzheimer’s disease (AD) is a very frequent neurodegenerative disorder characterized by an accumulation of amyloid-β (Aβ). Acitretin, a retinoid-derivative and approved treatment for Psoriasis vulgaris, increases non-amyloidogenic Amyloid-Precursor-Protein-(APP)-processing, prevents Aβ-production and elicits cognitive improvement in AD mouse models. As an unintended side effect, acitretin could result in hyperlipidemia. Here, we analyzed the impact of acitretin on the lipidome in brain and liver tissue in the 5xFAD mouse-model. In line with literature, triglycerides were increased in liver accompanied by increased PCaa, plasmalogens and acyl-carnitines, whereas SM-species were decreased. In brain, these effects were partially enhanced or similar but also inverted. While for SM and plasmalogens similar effects were found, PCaa, TAG and acyl-carnitines showed an inverse effect in both tissues. Our findings emphasize, that potential pharmaceuticals to treat AD should be carefully monitored with respect to lipid-homeostasis because APP-processing itself modulates lipid-metabolism and medication might result in further and unexpected changes. Moreover, deducing effects of brain lipid-homeostasis from results obtained for other tissues should be considered cautiously. With respect to acitretin, the increase in brain plasmalogens might display a further positive probability in AD-treatment, while other results, such as decreased SM, indicate the need of medical surveillance for treated patients.


Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3261
Author(s):  
Xiao Liu ◽  
Qian Zhou ◽  
Jia-He Zhang ◽  
Xiaoying Wang ◽  
Xiumei Gao ◽  
...  

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.


2019 ◽  
Vol 12 (2) ◽  
pp. 93 ◽  
Author(s):  
Shashank Masaldan ◽  
Abdel Ali Belaidi ◽  
Scott Ayton ◽  
Ashley I. Bush

Iron dyshomeostasis is a feature of Alzheimer’s disease (AD). The impact of iron on AD is attributed to its interactions with the central proteins of AD pathology (amyloid precursor protein and tau) and/or through the iron-mediated generation of prooxidant molecules (e.g., hydroxyl radicals). However, the source of iron accumulation in pathologically relevant regions of the brain and its contribution to AD remains unclear. One likely contributor to iron accumulation is the age-associated increase in tissue-resident senescent cells that drive inflammation and contribute to various pathologies associated with advanced age. Iron accumulation predisposes ageing tissue to oxidative stress that can lead to cellular dysfunction and to iron-dependent cell death modalities (e.g., ferroptosis). Further, elevated brain iron is associated with the progression of AD and cognitive decline. Elevated brain iron presents a feature of AD that may be modified pharmacologically to mitigate the effects of age/senescence-associated iron dyshomeostasis and improve disease outcome.


2019 ◽  
Vol 1124 ◽  
pp. 165-172
Author(s):  
Daniela Delfino ◽  
Diana Valeria Rossetti ◽  
Claudia Martelli ◽  
Ilaria Inserra ◽  
Federica Vincenzoni ◽  
...  

2013 ◽  
Vol 781-784 ◽  
pp. 643-646
Author(s):  
Xiao Lin ◽  
Li Yu

In this study, we aim to investigate the effect of curcumin on the expression of a-synuclein in the APPswe/PS1dE9 double transgenic mice. APPswe/PS1dE9 double transgenic mice were used as AD (Alzheimer's disease) model and fed with different concentrations of curcumin every day for 6 months, then immunohistochemistry method were used to detect the expression of a-synuclein in hippocampus of mice. The expression of a-syn in hippocampal neuron was decreased significantly after treated with 0.16g/kg to 1.0g/kg curcumin, the change was apparent in dose-dependent manner (P<0.05). a-synuclein pay an important role in the genesis and development of Alzheimer's disease and decreased level of a-synuclein might contribute to the neuroprotective effect of Curcumin, which may become a new target for the prevention and treatment of Alzheimer's disease.


2021 ◽  
Vol 11 ◽  
Author(s):  
Elisa Canepa ◽  
Silvia Fossati

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most prevalent cause of dementia. The main cerebral histological hallmarks are represented by parenchymal insoluble deposits of amyloid beta (Aβ plaques) and neurofibrillary tangles (NFT), intracellular filamentous inclusions of tau, a microtubule-associated protein. It is well-established that cerebrovascular dysfunction is an early feature of AD pathology, but the detrimental mechanisms leading to blood vessel impairment and the associated neurovascular deregulation are not fully understood. In 90% of AD cases, Aβ deposition around the brain vasculature, known as cerebral amyloid angiopathy (CAA), alters blood brain barrier (BBB) essential functions. While the effects of vascular Aβ accumulation are better documented, the scientific community has only recently started to consider the impact of tau on neurovascular pathology in AD. Emerging compelling evidence points to transmission of neuronal tau to different brain cells, including astrocytes, as well as to the release of tau into brain interstitial fluids, which may lead to perivascular neurofibrillar tau accumulation and toxicity, affecting vessel architecture, cerebral blood flow (CBF), and vascular permeability. BBB integrity and functionality may therefore be impacted by pathological tau, consequentially accelerating the progression of the disease. Tau aggregates have also been shown to induce mitochondrial damage: it is known that tau impairs mitochondrial localization, distribution and dynamics, alters ATP and reactive oxygen species production, and compromises oxidative phosphorylation systems. In light of this previous knowledge, we postulate that tau can initiate neurovascular pathology in AD through mitochondrial dysregulation. In this review, we will explore the literature investigating tau pathology contribution to the malfunction of the brain vasculature and neurovascular unit, and its association with mitochondrial alterations and caspase activation, in cellular, animal, and human studies of AD and tauopathies.


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