scholarly journals Presenilin-2 and Calcium Handling: Molecules, Organelles, Cells and Brain Networks

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2166 ◽  
Author(s):  
Paola Pizzo ◽  
Emy Basso ◽  
Riccardo Filadi ◽  
Elisa Greotti ◽  
Alessandro Leparulo ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Memory Loss ◽  
Amyloid Β ◽  
Brain Network ◽  
Calcium Handling ◽  
Catalytic Core ◽  
Multifunctional Protein ◽  
Presenilin 2 ◽  
Organelle Communication

Presenilin-2 (PS2) is one of the three proteins that are dominantly mutated in familial Alzheimer’s disease (FAD). It forms the catalytic core of the γ-secretase complex—a function shared with its homolog presenilin-1 (PS1)—the enzyme ultimately responsible of amyloid-β (Aβ) formation. Besides its enzymatic activity, PS2 is a multifunctional protein, being specifically involved, independently of γ-secretase activity, in the modulation of several cellular processes, such as Ca2+ signalling, mitochondrial function, inter-organelle communication, and autophagy. As for the former, evidence has accumulated that supports the involvement of PS2 at different levels, ranging from organelle Ca2+ handling to Ca2+ entry through plasma membrane channels. Thus FAD-linked PS2 mutations impact on multiple aspects of cell and tissue physiology, including bioenergetics and brain network excitability. In this contribution, we summarize the main findings on PS2, primarily as a modulator of Ca2+ homeostasis, with particular emphasis on the role of its mutations in the pathogenesis of FAD. Identification of cell pathways and molecules that are specifically targeted by PS2 mutants, as well as of common targets shared with PS1 mutants, will be fundamental to disentangle the complexity of memory loss and brain degeneration that occurs in Alzheimer’s disease (AD).

scholarly journals Induced Pluripotent Stem Cell-Derived Neural Precursors Improve Memory, Synaptic and Pathological Abnormalities in a Mouse Model of Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1802
Author(s):  
Enrique Armijo ◽  
George Edwards ◽  
Andrea Flores ◽  
Jorge Vera ◽  
Mohammad Shahnawaz ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Symptoms ◽  
Memory Loss ◽  
Amyloid Β ◽  
Cerebral Atrophy ◽  
Brain Inflammation ◽  
Neural Precursors ◽  
Model Of Alzheimer’S Disease ◽  
Induced Pluripotent

Alzheimer’s disease (AD) is the most common type of dementia in the elderly population. The disease is characterized by progressive memory loss, cerebral atrophy, extensive neuronal loss, synaptic alterations, brain inflammation, extracellular accumulation of amyloid-β (Aβ) plaques, and intracellular accumulation of hyper-phosphorylated tau (p-tau) protein. Many recent clinical trials have failed to show therapeutic benefit, likely because at the time in which patients exhibit clinical symptoms the brain is irreversibly damaged. In recent years, induced pluripotent stem cells (iPSCs) have been suggested as a promising cell therapy to recover brain functionality in neurodegenerative diseases such as AD. To evaluate the potential benefits of iPSCs on AD progression, we stereotaxically injected mouse iPSC-derived neural precursors (iPSC-NPCs) into the hippocampus of aged triple transgenic (3xTg-AD) mice harboring extensive pathological abnormalities typical of AD. Interestingly, iPSC-NPCs transplanted mice showed improved memory, synaptic plasticity, and reduced AD brain pathology, including a reduction of amyloid and tangles deposits. Our findings suggest that iPSC-NPCs might be a useful therapy that could produce benefit at the advanced clinical and pathological stages of AD.

scholarly journals Case of early-onset Alzheimer’s disease with atypical manifestation

2021 ◽  
Vol 34 (1) ◽  
pp. e100283
Author(s):  
Lin Zhu ◽  
Limin Sun ◽  
Lin Sun ◽  
Shifu Xiao
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Manifestation ◽  
Early Onset ◽  
Short Term Memory ◽  
Brain Mri ◽  
Memory Loss ◽  
Amyloid Β ◽  
Amyloid Β Protein ◽  
Fluent Aphasia

Short-term memory decline is the typical clinical manifestation of Alzheimer’s disease (AD). However, early-onset AD usually has atypical symptoms and may get misdiagnosed. In the present case study, we reported a patient who experienced symptoms of memory loss with progressive non-fluent aphasia accompanied by gradual social withdrawal. He did not meet the diagnostic criteria of AD based on the clinical manifestation and brain MRI. However, his cerebrospinal fluid examination showed a decreased level of beta-amyloid 42, and increased total tau and phosphorylated tau. Massive amyloid β-protein deposition by 11C-Pittsburgh positron emission tomography confirmed the diagnosis of frontal variant AD. This case indicated that early-onset AD may have progressive non-fluent aphasia as the core manifestation. The combination of individual and precision diagnosis would be beneficial for similar cases.

scholarly journals Comparison of Amyloid β and Tau Spread Models in Alzheimer’s Disease

2018 ◽  
Vol 29 (10) ◽  
pp. 4291-4302 ◽  
Author(s):  
Hang-Rai Kim ◽  
Peter Lee ◽  
Sang Won Seo ◽  
Jee Hoon Roh ◽  
Minyoung Oh ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Amyloid Β ◽  
Brain Network ◽  
Amyloid Positron Emission Tomography ◽  
Local Spread ◽  
Positron Emission ◽  
Spread Model ◽  
Graph Theoretical Approach

Abstract Tau and amyloid β (Aβ), 2 key pathogenic proteins in Alzheimer’s disease (AD), reportedly spread throughout the brain as the disease progresses. Models of how these pathogenic proteins spread from affected to unaffected areas had been proposed based on the observation that these proteins could transmit to other regions either through neural fibers (transneuronal spread model) or through extracellular space (local spread model). In this study, we modeled the spread of tau and Aβ using a graph theoretical approach based on resting-state functional magnetic resonance imaging. We tested whether these models predict the distribution of tau and Aβ in the brains of AD spectrum patients. To assess the models’ performance, we calculated spatial correlation between the model-predicted map and the actual map from tau and amyloid positron emission tomography. The transneuronal spread model predicted the distribution of tau and Aβ deposition with significantly higher accuracy than the local spread model. Compared with tau, the local spread model also predicted a comparable portion of Aβ deposition. These findings provide evidence of transneuronal spread of AD pathogenic proteins in a large-scale brain network and furthermore suggest different contributions of spread models for tau and Aβ in AD.

Targeted delivery of montelukast for treatment of Alzheimer’s disease

2021 ◽  
Vol 20 ◽  
Author(s):  
Ashok K. Datusalia ◽  
Gurpreet Singh ◽  
Nikita Yadav ◽  
Sachin Gaun ◽  
Moumita Manik ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Targeted Delivery ◽  
Symptomatic Relief ◽  
Memory Loss ◽  
Amyloid Β ◽  
Lessons Learned ◽  
Nano Structure ◽  
Substantial Impact ◽  
Structure Lipid

: Alzheimer’s disease (AD) is one of the most common neurodegenerative disease, which affect millions of people worldwide. Accumulation of amyloid-β plaques and hyperphosphorylated neurofibrillary tangles are the key mechanisms involved in the etiopathogenesis of AD, characterized by memory loss and behavioural changes. Effective therapies targeting AD pathogenesis are limited, making it the largest unmet clinical need. Unfortunately, the available drugs provide symptomatic relief and primary care, with no substantial impact on the disease pathology. However, in recent years researchers are working hard on several potential therapeutic targets to combat disease pathogenesis and few drugs have also reached clinical trials. In addition, drugs are being repurposed both in the preclinical and clinical studies for the treatment of AD. For instance, montelukast is most commonly used leukotriene receptor antagonist, for treating asthma and seasonal allergy. Its leukotriene antagonistic action can also be beneficial for the reduction of detrimental effects of leukotriene against neuro-inflammation, an hallmark feature of AD. The available marketed formulations of montelukast present challenges such as poor bioavailability and reduced uptake, reflecting the lack of effectiveness of its desired action in the CNS. While on the other side targeted drug delivery is a satisfactory approach to surpass the challenges associated with the therapeutic agents. This review will discuss the enhancement of montelukast treatment efficacy and its access to CNS, by using new approaches like nano-formulation, nasal gel, solid lipid formulation, nano-structure lipid carrier (NSLC), highlighting lessons learned to target AD pathologies and hurdles that persist.

MR Brain Screening using Optimization Techniques – A survey

2021 ◽  
Vol 17 ◽  
Author(s):  
Chitradevi D ◽  
Prabha S.
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Symptoms ◽  
Memory Loss ◽  
Amyloid Β ◽  
Cell Loss ◽  
Optimization Techniques ◽  
Amyloid Β Protein ◽  
The Brain ◽  
Brain Tissues

Background: Alzheimer’s disease (AD) is associated with Dementia, and it is also a memory syndrome in the brain. It affects the brain tissues and causes major changes in day-to-day activities. Aging is a major cause of Alzheimer's disease. AD is characterized by two pathological hallmarks as, Amyloid β protein and neurofibrillary tangles of hyperphosphorylated tau protein. The imaging hallmarks for Alzheimer’s disease are namely, swelling, shrinkage of brain tissues due to cell loss, and atrophy in the brain due to protein dissemination. Based on the survey, 60% to 80% of dementia patients belong to Alzheimer’s disease. Introduction: AD is now becoming an increasing and important brain disease. The goal of AD pathology is to cause changes/damage in brain tissues. Alzheimer's disease is thought to begin 20 years or more before symptoms appear, with tiny changes in the brain that are undetectable to the person affected. The changes in a person's brain after a few years are noticeable through symptoms such as language difficulties and memory loss. Neurons in different parts of the brain have detected symptoms such as cognitive impairments and learning disabilities. In this case, neuroimaging tools are necessary to identify the development of pathology which relates to the clinical symptoms. Methods: Several approaches have been tried during the last two decades for brain screening to analyse AD with the process of pre-processing, segmentation and classification. Different individual such as Grey Wolf optimization, Lion Optimization, Ant Lion Optimization and so on. Similarly, hybrid optimization techniques are also attempted to segment the brain sub-regions which helps in identifying the bio-markers to analyse AD. Conclusion: This study discusses a review of neuroimaging technologies for diagnosing Alzheimer's disease, as well as the discovery of hallmarks for the disease and the methodologies for finding hallmarks from brain images to evaluate AD. According to the literature review, most of the techniques predicted higher accuracy (more than 90%), which is beneficial for assessing and screening neurodegenerative illness, particularly Alzheimer's disease.

scholarly journals Alzheimer’s disease: many failed trials, so where do we go from here?

2020 ◽  
Vol 68 (6) ◽  
pp. 1135-1140 ◽  
Author(s):  
Allison Bethanne Reiss ◽  
Amy D Glass ◽  
Thomas Wisniewski ◽  
Benjamin Wolozin ◽  
Irving H Gomolin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Current Knowledge ◽  
Memory Loss ◽  
Treatment Strategies ◽  
Amyloid Β ◽  
Tau Proteins ◽  
Brain Disorder ◽  
The Central Nervous System ◽  
Progressive Cognitive Impairment

Alzheimer’s disease (AD) is a neurodegenerative brain disorder associated with relentlessly progressive cognitive impairment and memory loss. AD pathology proceeds for decades before cognitive deficits become clinically apparent, opening a window for preventative therapy. Imbalance of clearance and buildup of amyloid β and phosphorylated tau proteins in the central nervous system is believed to contribute to AD pathogenesis. However, multiple clinical trials of treatments aimed at averting accumulation of these proteins have yielded little success, and there is still no disease-modifying intervention. Here, we discuss current knowledge of AD pathology and treatment with an emphasis on emerging biomarkers and treatment strategies.

scholarly journals Intracellular Calcium Dysregulation by the Alzheimer’s Disease-Linked Protein Presenilin 2

2020 ◽  
Vol 21 (3) ◽  
pp. 770 ◽  
Author(s):  
Luisa Galla ◽  
Nelly Redolfi ◽  
Tullio Pozzan ◽  
Paola Pizzo ◽  
Elisa Greotti
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Autosomal Dominant ◽  
Amyloid Β ◽  
Presenilin 1 ◽  
Calcium Dysregulation ◽  
Aβ Peptides ◽  
Functional Consequences ◽  
Presenilin 2 ◽  
Amyloid Cascade

Alzheimer’s disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis.

Extraction of Polysaccharides From Bletilla Striata Using a Modified Low-temperature Method and Evaluation of Their Efficacy Against Alzheimer’s Disease

2021 ◽  
Author(s):  
Yi-Wen Lin ◽  
Chih-Hsiang Fang ◽  
Hung-Hsiang Liao ◽  
Feng Huei Lin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Low Temperature ◽  
Memory Loss ◽  
Amyloid Β ◽  
Ulcer Bleeding ◽  
Bletilla Striata ◽  
Temperature Method

Abstract Background: Amyloid-β (Aβ) peptides play a key role in Alzheimer’s disease (AD), the most common type of dementia. AD is characterized by progressive cognitive and memory loss accompanied by personality changes. Bletilla striata, a traditional Chinese medicine, has been widely used in Eastern Asian countries for alimentary canal damage, ulcer, bleeding, bruises, and burns. in this study, we investigated whether BSP could prevent the ROS from Aβ and the possibility to recover from the disease by memory improvement.Methods: In this study, a polysaccharide from Bletilla striata (BSP) with strong antioxidant and anti-inflammatory properties was extracted following a low-temperature method and tested for its efficacy against AD in vitro using N2a and BV-2 cells and in vivo using AD rats.Results: The characterization of the extracted BSP for its molecular structure and the functional group demonstrated the efficiency of the modified method to retain its bioactivity. In vitro, BSP reduced ROS levels in N2a cells and the expression levels of inflammatory-related genes in BV-2 cells treated with Aβ fibrils. In vivo, BSP recovered the learning memory, ameliorated the morphological damages in the hippocampus and cortex, and reduced the expression of the β-secretase protein in AlCl3-induced AD rats.Conclusions: To the best of our knowledge, this is the first study of BSP applicating in AD. Collectively, these findings demonstrated the efficacy of BSP to prevent and alleviate the effects of AD.

scholarly journals Dedifferentiation orchestrated through remodeling of the chromatin landscape defines PSEN1 mutation-induced Alzheimer’s Disease

2019 ◽  
Author(s):  
Andrew B. Caldwell ◽  
Qing Liu ◽  
Gary P. Schroth ◽  
Rudolph E. Tanzi ◽  
Douglas R. Galasko ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Late Onset ◽  
Disease Model ◽  
Memory Loss ◽  
Amyloid Β ◽  
Chromatin Accessibility ◽  
Experimental Models ◽  
Patient Specific

AbstractEarly-Onset Familial Alzheimer’s Disease (EOFAD) is a dominantly inherited neurodegenerative disorder elicited by mutations in the PSEN1, PSEN2, and APP genes1. Hallmark pathological changes and symptoms observed, namely the accumulation of misfolded Amyloid-β (Aβ) in plaques and Tau aggregates in neurofibrillary tangles associated with memory loss and cognitive decline, are understood to be temporally accelerated manifestations of the more common sporadic Late-Onset Alzheimer’s Disease. The complete penetrance of EOFAD-causing mutations has allowed for experimental models which have proven integral to the overall understanding of AD2. However, the failure of pathology-targeting therapeutic development suggests that the formation of plaques and tangles may be symptomatic and not describe the etiology of the disease3,4. Here, we use an integrative, multi-omics approach and systems-level analysis in hiPSC-derived neurons to generate a mechanistic disease model for EOFAD. Using patient-specific cells from donors harboring mutations in PSEN1 differentiated into neurons, we characterize the disease-related gene expression and chromatin accessibility changes by RNA- Seq, ATAC-Seq, and histone methylation ChIP-Seq. We show that the defining disease-causing mechanism of EOFAD is dedifferentiation, primarily through the REST-mediated repression of neuronal lineage specification gene programs and the activation of non-specific germ layer precursor gene programs concomitant with modifications in chromatin accessibility. These gene signature profiles and changes in chromatin topology illustrate that EOFAD neurons traverse the chromatin landscape from an ectodermal origin to a mixed germ lineage state. Further, a reanalysis of existing transcriptomic data from PSEN1 patient brain samples demonstrates that the mechanisms identified in our experimental system recapitulate EOFAD in the human brain. Our results comprise a disease model which describes the mechanisms culminating in dedifferentiation that precede amyloid and tau pathology formation and engender neurodegeneration.

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