Exploring the Potential of Neuroproteomics in Alzheimer's Disease

2020 ◽  
Vol 20 (25) ◽  
pp. 2263-2278 ◽  
Author(s):  
Md. Sahab Uddin ◽  
Md. Tanvir Kabir ◽  
Md. Jakaria ◽  
Eduardo Sobarzo-Sánchez ◽  
George E. Barreto ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Drug Targets ◽  
Senile Plaques ◽  
Brain Regions ◽  
Hyperphosphorylated Tau ◽  
Clinical Expression ◽  
Underlying Processes ◽  
With Memory

Alzheimer's disease (AD) is progressive brain amyloidosis that damages brain regions associated with memory, thinking, behavioral and social skills. Neuropathologically, AD is characterized by intraneuronal hyperphosphorylated tau inclusions as neurofibrillary tangles (NFTs), and buildup of extracellular amyloid-beta (Aβ) peptide as senile plaques. Several biomarker tests capturing these pathologies have been developed. However, for the full clinical expression of the neurodegenerative events of AD, there exist other central molecular pathways. In terms of understanding the unidentified underlying processes for the progression and development of AD, a complete comprehension of the structure and composition of atypical aggregation of proteins is essential. Presently, to aid the prognosis, diagnosis, detection, and development of drug targets in AD, neuroproteomics is elected as one of the leading essential tools for the efficient exploratory discovery of prospective biomarker candidates estimated to play a crucial role. Therefore, the aim of this review is to present the role of neuroproteomics to analyze the complexity of AD.

scholarly journals Neuropathology of Aging in Cats and its Similarities to Human Alzheimer’s Disease

2021 ◽  
Vol 2 ◽  
Author(s):  
Lorena Sordo ◽  
Alessandra C. Martini ◽  
E. Fiona Houston ◽  
Elizabeth Head ◽  
Danièlle Gunn-Moore
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Stage ◽  
Senile Plaques ◽  
Brain Regions ◽  
Hyperphosphorylated Tau ◽  
Age Related ◽  
Cat Brain ◽  
Amyloid Aβ ◽  
Intraneuronal Aβ

Elderly cats develop age-related behavioral and neuropathological changes that ultimately lead to cognitive dysfunction syndrome (CDS). These neuropathologies share similarities to those seen in the brains of humans with Alzheimer’s disease (AD), including the extracellular accumulation of ß-amyloid (Aβ) and intraneuronal deposits of hyperphosphorylated tau, which are considered to be the two major hallmarks of AD. The present study assessed the presence and distribution of Aβ and tau hyperphosphorylation within the cat brain (n = 55 cats), and how the distribution of these proteins changes with age and the presence of CDS. For this, immunohistochemistry was performed on seven brain regions from cats of various ages, with and without CDS (n = 10 with CDS). Cats accumulate both intracytoplasmic and extracellular deposits of Aβ, as well as intranuclear and intracytoplasmic hyperphosphorylated tau deposits. Large extracellular aggregates of Aβ were found in elderly cats, mainly in the cortical brain areas, with occasional hippocampal aggregates. This may suggest that these aggregates start in cortical areas and later progress to the hippocampus. While Aβ senile plaques in people with AD have a dense core, extracellular Aβ deposits in cats exhibited a diffuse pattern, similar to the early stages of plaque pathogenesis. Intraneuronal Aβ deposits were also observed, occurring predominantly in cortical brain regions of younger cats, while older cats had few to no intraneuronal Aβ deposits, especially when extracellular aggregates were abundant. Intracytoplasmic hyperphosphorylated tau was found within neurons in the brains of elderly cats, particularly in those with CDS. Due to their ultrastructural features, these deposits are considered to be pre-tangles, which are an early stage of the neurofibrillary tangles seen in AD. The largest numbers of pre-tangles are found mainly in the cerebral cortex of elderly cats, whereas lower numbers were found in other regions (i.e., entorhinal cortex and hippocampus). For the first time, intranuclear tau was found in both phosphorylated and non-phosphorylated states within neurons in the cat brain. The highest numbers of intranuclear deposits were found in the cortex of younger cats, and this tended to decrease with age. In contrast, elderly cats with pre-tangles had only occasional or no nuclear labelling.

scholarly journals Possible Clues for Brain Energy Translation via Endolysosomal Trafficking of APP-CTFs in Alzheimer’s Disease

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Senthilkumar Sivanesan ◽  
Ravi Mundugaru ◽  
Jayakumar Rajadas
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Ketone Bodies ◽  
Brain Regions ◽  
Pentose Phosphate ◽  
Lactate Shuttle ◽  
Carboxy Terminal ◽  
Brain Energy

Vascular dysfunctions, hypometabolism, and insulin resistance are high and early risk factors for Alzheimer’s disease (AD), a leading neurological disease associated with memory decline and cognitive dysfunctions. Early defects in glucose transporters and glycolysis occur during the course of AD progression. Hypometabolism begins well before the onset of early AD symptoms; this timing implicates the vulnerability of hypometabolic brain regions to beta-secretase 1 (BACE-1) upregulation, oxidative stress, inflammation, synaptic failure, and cell death. Despite the fact that ketone bodies, astrocyte-neuron lactate shuttle, pentose phosphate pathway (PPP), and glycogenolysis compensate to provide energy to the starving AD brain, a considerable energy crisis still persists and increases during disease progression. Studies that track brain energy metabolism in humans, animal models of AD, and in vitro studies reveal striking upregulation of beta-amyloid precursor protein (β-APP) and carboxy-terminal fragments (CTFs). Currently, the precise role of CTFs is unclear, but evidence supports increased endosomal-lysosomal trafficking of β-APP and CTFs through autophagy through a vague mechanism. While intracellular accumulation of Aβ is attributed as both the cause and consequence of a defective endolysosomal-autophagic system, much remains to be explored about the other β-APP cleavage products. Many recent works report altered amino acid catabolism and expression of several urea cycle enzymes in AD brains, but the precise cause for this dysregulation is not fully explained. In this paper, we try to connect the role of CTFs in the energy translation process in AD brain based on recent findings.

Novel Therapeutic Mechanism of Action of Metformin and Its Nanoformulation in Alzheimer's Disease and Role of AKT/ERK/GSK Pathway.

2021 ◽  
Author(s):  
Harish Kumar ◽  
Amitava Chakrabarti ◽  
Phulen Sarma ◽  
Manish Modi ◽  
Dibyajyoti Banerjee ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Control ◽  
Rat Model ◽  
Memory Impairment ◽  
Protective Efficacy ◽  
Control Group ◽  
Hyperphosphorylated Tau ◽  
Days Of Therapy

Abstract Background: Insulin resistance in brain plays a critical role in the pathogenesis of Alzheimer's disease (AD). Metformin is a blood brain barrier crossing anti-diabetic insulin-sensitizer drug. Current study has evaluated the therapeutic and mechanistic role of conventional as well as solid lipid nanoformulation (SLN) of metformin in intracerebro ventricular (ICV) Aβ (1-42) rat-model of AD. Methods: SLN-metformin was prepared by the micro-emulsification method and further evaluated by zetasizer and scanning electron-microscopy. In the animal experimental phase, AD was induced by bilateral ICV injection of Aβ using stereotaxic technique, whereas control group (sham) received ICV-NS. 14 days post-model induction, ICV- Aβ treated rats were further divided into 5 groups: disease control (no treatment), Metformin dose of (50mg/kg, 100mg/kg and 150 mg/kg), SLN of metformin 50mg/kg and memantine 1.8mg/kg (positive-control). Animals were tested for cognitive performance (in EPM, MWM) after 21 days of therapy, and then sacrificed. Brain homogenate was evaluated using ELISA for (Aβ (1-42), hyperphosphorylated tau, pAKTser473, GSK-3β, p-ERK,) and HPLC (metformin level). Brain histopathology was used to evaluate neuronal injury score (H&E) and Bcl2 and BAX (IHC). Results: The average size of SLN-metformin was <200 nm and was of spherical in shape with 94.08% entrapment efficiency. Compared to sham, the disease-control group showed significantly higher (p≤0.05) memory impairment (in MWM and EPM), higher hyperphosphorylated tau, Aβ (1-42), and Bax and lower Bcl-2 expression. Metformin was detectable in brain. Treatment with metformin and its SLN form significantly decreased the memory impairment as well as decreased the expression of hyperphosphorylated tau, Aβ(1-42), Bax expression and increased expression of Bcl-2 in brain. AKT-ERK-GSK3β-Hyperphosphorylated tau pathway can be implicated in the protective efficacy of metformin. Conclusion: Both metformin and SLN metformin is found to be effective as therapeutic agent in ICV-AB rat model of AD. AKT-ERK-GSK3β-Hyperphosphorylated tau pathway is found to be involved in the protective efficacy of metformin.

scholarly journals Factors underlying cognitive decline in old age and Alzheimer’s disease: the role of the hippocampus

2017 ◽  
Vol 28 (7) ◽  
pp. 705-714 ◽  
Author(s):  
Wafa Jaroudi ◽  
Julia Garami ◽  
Sandra Garrido ◽  
Michael Hornberger ◽  
Szabolcs Keri ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Decline ◽  
Personality Traits ◽  
Old Age ◽  
Brain Regions ◽  
Personality Factors ◽  
Associated Symptoms ◽  
Lifestyle Patterns

AbstractThere are many factors that strongly influence the aetiology, development, and progression of cognitive decline in old age, mild cognitive impairment (MCI), and Alzheimer’s disease (AD). These factors include not only different personality traits and moods but also lifestyle patterns (e.g. exercise and diet) and awareness levels that lead to cognitive decline in old age. In this review, we discuss how personality traits, mood states, and lifestyle impact brain and behaviour in older adults. Specifically, our review shows that these lifestyle and personality factors affect several brain regions, including the hippocampus, a region key for memory that is affected by cognitive decline in old age as well as AD. Accordingly, appropriate recommendations are presented in this review to assist individuals in decreasing chances of MCI, dementia, AD, and associated symptoms.

scholarly journals Entropy and Complexity Analyses in Alzheimer’s Disease: An MEG Study

2010 ◽  
Vol 4 (1) ◽  
pp. 223-235 ◽  
Author(s):  
Carlos Gómez ◽  
Roberto Hornero
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Fractal Dimension ◽  
Background Activity ◽  
Senile Plaques ◽  
Approximate Entropy ◽  
Brain Regions ◽  
Brain Disorder ◽  
Complexity Measures ◽  
Control Subjects

Alzheimer’s disease (AD) is one of the most frequent disorders among elderly population and it is considered the main cause of dementia in western countries. This irreversible brain disorder is characterized by neural loss and the appearance of neurofibrillary tangles and senile plaques. The aim of the present study was the analysis of the magnetoencephalogram (MEG) background activity from AD patients and elderly control subjects. MEG recordings from 36 AD patients and 26 controls were analyzed by means of six entropy and complexity measures: Shannon spectral entropy (SSE), approximate entropy (ApEn), sample entropy (SampEn), Higuchi’s fractal dimension (HFD), Maragos and Sun’s fractal dimension (MSFD), and Lempel-Ziv complexity (LZC). SSE is an irregularity estimator in terms of the flatness of the spectrum, whereas ApEn and SampEn are embbeding entropies that quantify the signal regularity. The complexity measures HFD and MSFD were applied to MEG signals to estimate their fractal dimension. Finally, LZC measures the number of different substrings and the rate of their recurrence along the original time series. Our results show that MEG recordings are less complex and more regular in AD patients than in control subjects. Significant differences between both groups were found in several brain regions using all these methods, with the exception of MSFD (p-value < 0.05, Welch’s t-test with Bonferroni’s correction). Using receiver operating characteristic curves with a leave-one-out cross-validation procedure, the highest accuracy was achieved with SSE: 77.42%. We conclude that entropy and complexity analyses from MEG background activity could be useful to help in AD diagnosis.

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.

scholarly journals Emerging Link between Alzheimer’s Disease and Homeostatic Synaptic Plasticity

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Sung-Soo Jang ◽  
Hee Jung Chung
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Synaptic Plasticity ◽  
Senile Plaques ◽  
Long Term Potentiation ◽  
Brain Regions ◽  
Synaptic Activity ◽  
Homeostatic Plasticity ◽  
Brain Disorder

Alzheimer’s disease (AD) is an irreversible brain disorder characterized by progressive cognitive decline and neurodegeneration of brain regions that are crucial for learning and memory. Although intracellular neurofibrillary tangles and extracellular senile plaques, composed of insoluble amyloid-β(Aβ) peptides, have been the hallmarks of postmortem AD brains, memory impairment in early AD correlates better with pathological accumulation of soluble Aβoligomers and persistent weakening of excitatory synaptic strength, which is demonstrated by inhibition of long-term potentiation, enhancement of long-term depression, and loss of synapses. However, current, approved interventions aiming to reduce Aβlevels have failed to retard disease progression; this has led to a pressing need to identify and target alternative pathogenic mechanisms of AD. Recently, it has been suggested that the disruption of Hebbian synaptic plasticity in AD is due to aberrant metaplasticity, which is a form of homeostatic plasticity that tunes the magnitude and direction of future synaptic plasticity based on previous neuronal or synaptic activity. This review examines emerging evidence for aberrant metaplasticity in AD. Putative mechanisms underlying aberrant metaplasticity in AD will also be discussed. We hope this review inspires future studies to test the extent to which these mechanisms contribute to the etiology of AD and offer therapeutic targets.

scholarly journals Relationship of Wine Consumption with Alzheimer’s Disease

Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 206 ◽  
Author(s):  
Reale ◽  
Costantini ◽  
Jagarlapoodi ◽  
Khan ◽  
Belwal ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Alcohol Intake ◽  
Senile Plaques ◽  
Neuronal Loss ◽  
Language Function ◽  
Reduce Risk ◽  
Relationship Of ◽  
The Relationship

Background: Alzheimer’s disease (AD), the most threatening neurodegenerative disease, is characterized by the loss of memory and language function, an unbalanced perception of space, and other cognitive and physical manifestations. The pathology of AD is characterized by neuronal loss and the extensive distribution of senile plaques and neurofibrillary tangles (NFTs). The role of environment and the diet in AD is being actively studied, and nutrition is one of the main factors playing a prominent role in the prevention of neurodegenerative diseases. In this context, the relationship between dementia and wine use/abuse has received increased research interest, with varying and often conflicting results. Scope and Approach: With this review, we aimed to critically summarize the main relevant studies to clarify the relationship between wine drinking and AD, as well as how frequency and/or amount of drinking may influence the effects. Key Findings and Conclusions: Overall, based on the interpretation of various studies, no definitive results highlight if light to moderate alcohol drinking is detrimental to cognition and dementia, or if alcohol intake could reduce risk of developing AD.

scholarly journals An App knock-in rat model for Alzheimer’s disease exhibiting Aβ and tau pathologies, neuronal death and cognitive impairments

Cell Research ◽  
2021 ◽  
Author(s):  
Keliang Pang ◽  
Richeng Jiang ◽  
Wei Zhang ◽  
Zhengyi Yang ◽  
Lin-Lin Li ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Progression ◽  
Rat Model ◽  
Neuronal Death ◽  
Drug Targets ◽  
Ectopic Expression ◽  
Drug Efficacy ◽  
Brain Regions ◽  
Tau Pathology

AbstractA major obstacle in Alzheimer’s disease (AD) research is the lack of predictive and translatable animal models that reflect disease progression and drug efficacy. Transgenic mice overexpressing amyloid precursor protein (App) gene manifest non-physiological and ectopic expression of APP and its fragments in the brain, which is not observed in AD patients. The App knock-in mice circumvented some of these problems, but they do not exhibit tau pathology and neuronal death. We have generated a rat model, with three familiar App mutations and humanized Aβ sequence knocked into the rat App gene. Without altering the levels of full-length APP and other APP fragments, this model exhibits pathologies and disease progression resembling those in human patients: deposit of Aβ plaques in relevant brain regions, microglia activation and gliosis, progressive synaptic degeneration and AD-relevant cognitive deficits. Interestingly, we have observed tau pathology, neuronal apoptosis and necroptosis and brain atrophy, phenotypes rarely seen in other APP models. This App knock-in rat model may serve as a useful tool for AD research, identifying new drug targets and biomarkers, and testing therapeutics.

Navigating Alzheimer’s Disease via Chronic Stress: The Role of Glucocorticoids

2020 ◽  
Vol 21 (5) ◽  
pp. 433-444 ◽  
Author(s):  
Vivek Kumar Sharma ◽  
Thakur Gurjeet Singh
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Chronic Stress ◽  
Glucocorticoid Receptors ◽  
Molecular Mechanisms ◽  
Senile Plaques ◽  
Symptomatic Relief ◽  
Therapeutic Interventions ◽  
Physiological Status

Alzheimer’s disease (AD) is a chronic intensifying incurable progressive disease leading to neurological deterioration manifested as impairment of memory and executive brain functioning affecting the physical ability like intellectual brilliance, common sense in patients. The recent therapeutic approach in Alzheimer&#039;s disease is only the symptomatic relief further emerging the need for therapeutic strategies to be targeted in managing the underlying silent killing progression of dreaded pathology. Therefore, the current research direction is focused on identifying the molecular mechanisms leading to the evolution of the understanding of the neuropathology of Alzheimer&#039;s disease. The resultant saturation in the area of current targets (amyloid &#946;, &#964; Protein, oxidative stress etc.) has led the scientific community to rethink of the mechanistic neurodegenerative pathways and reprogram the current research directions. Although, the role of stress has been recognized for many years and contributing to the development of cognitive impairment, the area of stress has got the much-needed impetus recently and is being recognized as a modifiable menace for AD. Stress is an unavoidable human experience that can be resolved and normalized but chronic activation of stress pathways unsettle the physiological status. Chronic stress mediated activation of neuroendocrine stimulation is generally linked to a high risk of developing AD. Chronic stress-driven physiological dysregulation and hypercortisolemia intermingle at the neuronal level and leads to functional (hypometabolism, excitotoxicity, inflammation) and anatomical remodeling of the brain architecture (senile plaques, τ tangles, hippocampal atrophy, retraction of spines) ending with severe cognitive deterioration. The present review is an effort to collect the most pertinent evidence that support chronic stress as a realistic and modifiable therapeutic earmark for AD and to advocate glucocorticoid receptors as therapeutic interventions.

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