scholarly journals Expression of Exosome Biogenesis Genes is Pervasively Altered by Aging in the Mouse and in the Human Brain During Alzheimer's Disease

2021 ◽  
Author(s):  
Dan Lark ◽  
Thomas J LaRocca
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Types ◽  
Cell Populations ◽  
Cell Type ◽  
Body Protein ◽  
Common Gene ◽  
Exosome Biogenesis ◽  
Age Related ◽  
The Impact

Extracellular vesicles (EVs) like exosomes are secreted by numerous cell types in a variety of tissues. EVs have been implicated in both aging and age-related disorders like Alzheimer's disease (AD). However, how aging and AD affect EV biogenesis within and across cell types is poorly understood. Moreover, cells acquire characteristics based on tissue niche, but the impact of tissue residence on cell type EV biogenesis is unknown. We explored the Tabula Muris Senis, Mayo RNA-seq and ROSMAP data sets to characterize the cell and tissue-specific effects of aging and AD on genes involved in EV biogenesis. Specifically, we examined the age-dependent expression (age coefficient) of genes involved in EV biogenesis (22 genes), EV cargo (3 genes) and senescence (5 genes). Of the 131 cell populations (cell type x tissue) studied, 95 have at least one EV biogenesis gene impacted by age. The most common gene increased by age was charged multivesicular body protein 2A (CHMP2A) (54 cell populations). The most common gene decreased by age was syndecan binding protein (SDCBP) (58 cell populations). The senescence-associated genes cyclin-dependent kinase 1A (CDKN1A) and CDKN2A were not related to changes in CHMP2A and SDCBP and were altered by age in fewer cell populations. Finally, individuals with AD had decreased CHMP2A and increased SDCBP expression, opposite of what is observed with aging in the absence of diagnosed neurological disease. These findings indicate that age modifies exosome biogenesis gene expression in many cell populations mostly independent of senescence, and may be further altered in AD.

scholarly journals Relationship between Wine Consumption, Diet and Microbiome Modulation in Alzheimer’s Disease

Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3082
Author(s):  
M. Victoria Moreno-Arribas ◽  
Begoña Bartolomé ◽  
José L. Peñalvo ◽  
Patricia Pérez-Matute ◽  
Maria José Motilva
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Neurodegenerative Disorder ◽  
Current Knowledge ◽  
Intestinal Microbiome ◽  
Dietary Polyphenols ◽  
Age Related ◽  
Wine Polyphenols ◽  
The Impact

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder leading to the most common form of dementia in elderly people. Modifiable dietary and lifestyle factors could either accelerate or ameliorate the aging process and the risk of developing AD and other age-related morbidities. Emerging evidence also reports a potential link between oral and gut microbiota alterations and AD. Dietary polyphenols, in particular wine polyphenols, are a major diver of oral and gut microbiota composition and function. Consequently, wine polyphenols health effects, mediated as a function of the individual’s oral and gut microbiome are considered one of the recent greatest challenges in the field of neurodegenerative diseases as a promising strategy to prevent or slow down AD progression. This review highlights current knowledge on the link of oral and intestinal microbiome and the interaction between wine polyphenols and microbiota in the context of AD. Furthermore, the extent to which mechanisms bacteria and polyphenols and its microbial metabolites exert their action on communication pathways between the brain and the microbiota, as well as the impact of the molecular mediators to these interactions on AD patients, are described.

scholarly journals Tau immunophenotypes in chronic traumatic encephalopathy recapitulate those of ageing and Alzheimer’s disease

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1572-1587 ◽  
Author(s):  
John D Arena ◽  
Douglas H Smith ◽  
Edward B Lee ◽  
Garrett S Gibbons ◽  
David J Irwin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disease ◽  
Chronic Traumatic Encephalopathy ◽  
Cell Types ◽  
Tau Pathology ◽  
Post Translational Modifications ◽  
Age Related ◽  
History Of ◽  
Severe Tbi

Abstract Traumatic brain injury (TBI) is a risk factor for neurodegenerative disease, including chronic traumatic encephalopathy (CTE). Preliminary consensus criteria define the pathognomonic lesion of CTE as patchy tau pathology within neurons and astrocytes at the depths of cortical sulci. However, the specific tau isoform composition and post-translational modifications in CTE remain largely unexplored. Using immunohistochemistry, we performed tau phenotyping of CTE neuropathologies and compared this to a range of tau pathologies, including Alzheimer’s disease, primary age-related tauopathy, ageing-related tau astrogliopathy and multiple subtypes of frontotemporal lobar degeneration with tau inclusions. Cases satisfying preliminary consensus diagnostic criteria for CTE neuropathological change (CTE-NC) were identified (athletes, n = 10; long-term survivors of moderate or severe TBI, n = 4) from the Glasgow TBI Archive and Penn Neurodegenerative Disease Brain Bank. In addition, material from a range of autopsy-proven ageing-associated and primary tauopathies in which there was no known history of exposure to TBI was selected as non-injured controls (n = 32). Each case was then stained with a panel of tau antibodies specific for phospho-epitopes (PHF1, CP13, AT100, pS262), microtubule-binding repeat domains (3R, 4R), truncation (Tau-C3) or conformation (GT-7, GT-38) and the extent and distribution of staining assessed. Cell types were confirmed with double immunofluorescent labelling. Results demonstrate that astroglial tau pathology in CTE is composed of 4R-immunoreactive thorn-shaped astrocytes, echoing the morphology and immunophenotype of astrocytes encountered in ageing-related tau astrogliopathy. In contrast, neurofibrillary tangles of CTE contain both 3R and 4R tau, with post-translational modifications and conformations consistent with Alzheimer’s disease and primary age-related tauopathy. Our observations establish that the astroglial and neurofibrillary tau pathologies of CTE are phenotypically distinct from each other and recapitulate the tau immunophenotypes encountered in ageing and Alzheimer’s disease. As such, the immunohistochemical distinction of CTE neuropathology from other mixed 3R/4R tauopathies of Alzheimer’s disease and ageing may rest solely on the pattern and distribution of pathology.

scholarly journals The Impact of Systemic Inflammation on Alzheimer’s Disease Pathology

2022 ◽  
Vol 12 ◽  
Author(s):  
Junhua Xie ◽  
Lien Van Hoecke ◽  
Roosmarijn E. Vandenbroucke
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Rational Design ◽  
Neurodegenerative Disorder ◽  
Peripheral Inflammation ◽  
Comprehensive Overview ◽  
Age Related ◽  
Symptomatic Medication ◽  
Inflammatory Processes ◽  
The Impact

Alzheimer’s disease (AD) is a devastating age-related neurodegenerative disorder with an alarming increasing prevalence. Except for the recently FDA-approved Aducanumab of which the therapeutic effect is not yet conclusively proven, only symptomatic medication that is effective for some AD patients is available. In order to be able to design more rational and effective treatments, our understanding of the mechanisms behind the pathogenesis and progression of AD urgently needs to be improved. Over the last years, it became increasingly clear that peripheral inflammation is one of the detrimental factors that can contribute to the disease. Here, we discuss the current understanding of how systemic and intestinal (referred to as the gut-brain axis) inflammatory processes may affect brain pathology, with a specific focus on AD. Moreover, we give a comprehensive overview of the different preclinical as well as clinical studies that link peripheral Inflammation to AD initiation and progression. Altogether, this review broadens our understanding of the mechanisms behind AD pathology and may help in the rational design of further research aiming to identify novel therapeutic targets.

Metabolic syndrome, Alzheimer's disease, and Covid 19: A possible correlation

2021 ◽  
Vol 18 ◽  
Author(s):  
Carmine Finelli
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Metabolic Syndrome ◽  
Current Knowledge ◽  
Future Research ◽  
Breathing Exercises ◽  
Lung Capacity ◽  
Age Related ◽  
Key Indicators ◽  
The Impact

: Age and comorbidities are key indicators of hospital admission, serious illness, and mortality in COVID-19 patients. Patients with age-related comorbidities, such as cardiovascular disease, hypertension, diabetes, chronic kidney disease, NAFLD, obesity, and metabolic syndrome, are more likely to require hospitalization and suffer severe sickness of COVID-19. Patients with Alzheimer’s disease and risk factors associated with dementia may also be more vulnerable to serious COVID-19 infection. Peripheral inflammation, including in patients who recover from illness, may promote the course of neurodegenerative disorders through neuroinflammatory pathways The aim of this study is to examine the impact of COVID-19 on immunity in patients with age-related diseases such as metabolic syndrome and Alzheimer’s disease and also to hypothesize the possible correlation between metabolic syndrome, Alzheimer’s disease, and COVID-19. Identifying the mechanisms that explain the complicated interaction between metabolic syndrome, Alzheimer’s disease, COVID-19, inflammation, and immunity could be crucial to designing effective pharmacological therapies and procedures. This study adds to our basic information about the new coronavirus by synthesizing current knowledge of these linkages. To reduce inflammation and enhance immunity, patients should acquire good lifestyle practices. Walking, breathing exercises, and a nutritious diet all help in improving lung capacity and immunity. Future research into novel therapeutics for patients with metabolic syndrome, Alzheimer’s disease, and COVID-19 inflammation and immunology is encouraged by this paper.

scholarly journals Expression weighted cell type enrichments reveal genetic and cellular nature of major brain disorders

2015 ◽  
Author(s):  
Nathan G. Skene ◽  
Seth G.N. Grant
Keyword(s):  
Multiple Sclerosis ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Types ◽  
Brain Diseases ◽  
Causative Mutation ◽  
Specific Marker ◽  
Brain Disorders ◽  
Cell Type ◽  
A Cell

AbstractThe cell types that trigger the primary pathology in many brain diseases remain largely unknown. One route to understanding the primary pathological cell type for a particular disease is to identify the cells expressing susceptibility genes. Although this is straightforward for monogenic conditions where the causative mutation may alter expression of a cell type specific marker, methods are required for the common polygenic disorders. We developed the Expression Weighted Cell Type Enrichment (EWCE) method that uses single cell transcriptomes to generate the probability distribution associated with a gene list having an average level of expression within a cell type. Following validation, we applied EWCE to human genetic data from cases of epilepsy, Schizophrenia, Autism, Intellectual Disability, Alzheimer’s disease, Multiple Sclerosis and anxiety disorders. Genetic susceptibility primarily affected microglia in Alzheimer’s and Multiple Sclerosis; was shared between interneurons and pyramidal neurons in Autism and Schizophrenia; while intellectual disabilities and epilepsy were attributable to a range of cell-types, with the strongest enrichment in interneurons. We hypothesized that the primary cell type pathology could trigger secondary changes in other cell types and these could be detected by applying EWCE to transcriptome data from diseased tissue. In Autism, Schizophrenia and Alzheimer’s disease we find evidence of pathological changes in all of the major brain cell types. These findings give novel insight into the cellular origins and progression in common brain disorders. The methods can be applied to any tissue and disorder and have applications in validating mouse models.

scholarly journals Allele-specific analysis reveals exon- and cell-type-specific regulatory effects of Alzheimer's disease-associated genetic variants

2021 ◽  
Author(s):  
Liang He ◽  
Yury Loika ◽  
Alexander Kulminski
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Variants ◽  
Mixed Model ◽  
Cell Types ◽  
Cell Type ◽  
Causal Pathways ◽  
Allele Specific ◽  
Cell Type Specific ◽  
Regulatory Effects

Elucidating regulatory effects of Alzheimer's disease (AD)-associated genetic variants is critical for unraveling their causal pathways and understanding the pathology. However, their cell-type-specific regulatory mechanisms in the brain remain largely unclear. Here, we conducted an analysis of allele-specific expression quantitative trait loci (aseQTLs) for 33 AD-associated variants in four brain regions and seven cell types using ~3000 bulk RNA-seq samples and >0.25 million single nuclei. We develop a flexible framework using a hierarchical Poisson mixed model unifying samples in both allelic and genotype-level expression data. We identified 24 AD-associated variants (~73%) that are allele-specific eQTLs (aseQTLs) in at least one brain region. Multiple aseQTLs are region-dependent or exon-specific, such as rs2093760 with CR1, rs7982 with CLU, and rs3865444 with CD33. Notably, the APOE e4 variant reduces APOE expression across all regions, even in healthy controls. In pinpointing the cell types responsible for the observed region-level aseQTLs, we found rs2093760 as an aseQTL of CR1 in oligodendrocytes but not in microglia. Many AD-associated variants are aseQTLs in microglia or monocytes of immune-related genes, including HLA-DQB1, HLA-DQA2, CD33, FCER1G, MS4A6A, SPI1, and BIN1, highlighting the regulatory role of AD-associated variants in the immune response. These findings provide further insights into potential causal pathways and cell types mediating the effects of the AD-associated variants.

scholarly journals THE INTERRELATIONSHIP BETWEEN INSULIN-LIKE GROWTH FACTOR 1, APOLIPOPROTEIN E Ε4, LIFESTYLE FACTORS, AND THE AGING BODY AND BRAIN

2020 ◽  
pp. 1-9
Author(s):  
S.A. Galle ◽  
I.K. Geraedts ◽  
J.B. Deijen ◽  
M.V. Milders ◽  
M.L. Drent
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Growth Factor ◽  
Apolipoprotein E ◽  
Cognitive Functioning ◽  
Brain Function ◽  
Healthy Aging ◽  
Insulin Like Growth Factor ◽  
Age Related ◽  
The Impact

Aging is associated with a decrease in body and brain function and with a decline in insulin-like growth factor 1 levels. The observed associations between alterations in insulin-like growth factor 1 levels and cognitive functioning and Mild Cognitive Impairment suggest that altered insulin-like growth factor 1 signaling may accompany Alzheimer’s disease or is involved in the pathogenesis of the disease. Recent animal research has suggested a possible association between insulin-like growth factor 1 levels and the Apolipoprotein E ε4 allele, a genetic predisposition to Alzheimer’s disease. It is therefore hypothesized that a reduction in insulin-like growth factor 1 signaling may moderate the vulnerability to Alzheimer’s disease of human Apolipoprotein E ε4 carriers. We address the impact of age-related decline of insulin-like growth factor 1 levels on physical and brain function in healthy aging and Alzheimer’s disease and discuss the links between insulin-like growth factor 1 and the Apolipoprotein E ε4 polymorphism. Furthermore, we discuss lifestyle interventions that may increase insulin-like growth factor 1 serum levels, including physical activity and adherence to a protein rich diet and the possible benefits to the physical fitness and cognitive functioning of the aging population.

Role of TREM2 in Alzheimer's Disease and its Consequences on β- Amyloid, Tau and Neurofibrillary Tangles

2020 ◽  
Vol 16 (13) ◽  
pp. 1216-1229 ◽  
Author(s):  
Anurag K. Singh ◽  
Gaurav Mishra ◽  
Anand Maurya ◽  
Rajendra Awasthi ◽  
Komal Kumari ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Tau Pathology ◽  
Functional Roles ◽  
Age Related ◽  
Β Amyloid ◽  
The Impact ◽  
Neuronal Stress

: Alzheimer's Disease (AD) is age-related neurodegenerative disorder recognized by a steadily gradual cognitive decline that has devastating personal and socioeconomic implications. Recently, some genetic factors for AD have been identified which attracted wide attention of researchers in different areas of AD biology and possible new therapeutic targets. Alternative forms of triggering receptor expressed on myeloid cells 2 (TREM2) genes are examples of such risk factors, which contribute higher risk for developing AD. Comprehending TREM2 function pledge to provide salient insight into how neuroinflammation contributes to AD pathology. The dearth of microglial TREM2 shepherd to augmented tau pathology is couple with frequent enhancement of activated neuronal stress kinases. The involvement of TREM2 in the regulation of tau-associated innate immune response of the CNS has clearly demonstrated through these findings. However, whether decrease level of TREM2 assists pathology of tau through changed clearance and pathological escalation of tau or through direct contact between microglia and neuron and any alternative possible mechanisms need to examine. This review briefly summarizes distinct functional roles of TREM2 in AD pathology and highlights the TREM2 gene regulation. We have also addressed the impact of TREM2 on β-amyloid plaques and tau pathology in Alzheimer’s disease.

scholarly journals Alterations of Transcription of Genes Coding Anti-oxidative and Mitochondria-Related Proteins in Amyloid β Toxicity: Relevance to Alzheimer’s Disease

2019 ◽  
Vol 57 (3) ◽  
pp. 1374-1388 ◽  
Author(s):  
Magdalena Cieślik ◽  
Grzegorz A. Czapski ◽  
Sylwia Wójtowicz ◽  
Iga Wieczorek ◽  
Przemysław L. Wencel ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Cortex ◽  
Neuronal Degeneration ◽  
Amyloid Β ◽  
Cell Types ◽  
Sirtuin 1 ◽  
Genes Encoding ◽  
Related Proteins ◽  
The Impact

AbstractA growing body of evidence indicates that pathological forms of amyloid beta (Aβ) peptide contribute to neuronal degeneration and synaptic loss in Alzheimer’s disease (AD). In this study, we investigated the impact of exogenous Aβ1-42 oligomers (AβO) and endogenously liberated Aβ peptides on transcription of genes for anti-oxidative and mitochondria-related proteins in cell lines (neuronal SH-SY5Y and microglial BV2) and in brain cortex of transgenic AD (Tg-AD) mice, respectively. Our results demonstrated significant AβO-evoked changes in transcription of genes in SH-SY5Y cells, where AβO enhanced expression of Sod1, Cat, mt-Nd1, Bcl2, and attenuated Sirt5, Sod2 and Sdha. In BV2 line, AβO increased the level of mRNA for Sod2, Dnm1l, Bcl2, and decreased for Gpx4, Sirt1, Sirt3, mt-Nd1, Sdha and Mfn2. Then, AβO enhanced free radicals level and impaired mitochondrial membrane potential only in SH-SY5Y cells, but reduced viability of both cell types. Inhibitor of poly(ADP-ribose)polymerase-1 and activator of sirtuin-1 more efficiently enhanced viability of SH-SY5Y than BV2 affected by AβO. Analysis of brain cortex of Tg-AD mice confirmed significant downregulation of Sirt1, Mfn1 and mt-Nd1 and upregulation of Dnm1l. In human AD brain, changes of microRNA pattern (miRNA-9, miRNA-34a, miRNA-146a and miRNA-155) seem to be responsible for decrease in Sirt1 expression. Overall, our results demonstrated a diverse response of neuronal and microglial cells to AβO toxicity. Alterations of genes encoding Sirt1, Mfn1 and Drp1 in an experimental model of AD suggest that modulation of mitochondria dynamics and Sirt1, including miRNA strategy, may be crucial for improvement of AD therapy.

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