scholarly journals TOMM40 RNA Transcription in Alzheimer’s Disease Brain and Its Implication in Mitochondrial Dysfunction

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 871
Author(s):  
Eun-Gyung Lee ◽  
Sunny Chen ◽  
Lesley Leong ◽  
Jessica Tulloch ◽  
Chang-En Yu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Postmortem Brain ◽  
Human Postmortem Brain ◽  
Mitochondrial Dna Copy Number ◽  
Mitochondrial Functions ◽  
Differential Transcription ◽  
And Control ◽  
Rna Levels

Increasing evidence suggests that the Translocase of Outer Mitochondria Membrane 40 (TOMM40) gene may contribute to the risk of Alzheimer’s disease (AD). Currently, there is no consensus as to whether TOMM40 expression is up- or down-regulated in AD brains, hindering a clear interpretation of TOMM40’s role in this disease. The aim of this study was to determine if TOMM40 RNA levels differ between AD and control brains. We applied RT-qPCR to study TOMM40 transcription in human postmortem brain (PMB) and assessed associations of these RNA levels with genetic variants in APOE and TOMM40. We also compared TOMM40 RNA levels with mitochondrial functions in human cell lines. Initially, we found that the human genome carries multiple TOMM40 pseudogenes capable of producing highly homologous RNAs that can obscure precise TOMM40 RNA measurements. To circumvent this obstacle, we developed a novel RNA expression assay targeting the primary transcript of TOMM40. Using this assay, we showed that TOMM40 RNA was upregulated in AD PMB. Additionally, elevated TOMM40 RNA levels were associated with decreases in mitochondrial DNA copy number and mitochondrial membrane potential in oxidative stress-challenged cells. Overall, differential transcription of TOMM40 RNA in the brain is associated with AD and could be an indicator of mitochondrial dysfunction.

scholarly journals Mitochondrial Dysfunction: Different Routes to Alzheimer’s Disease Therapy

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Pasquale Picone ◽  
Domenico Nuzzo ◽  
Luca Caruana ◽  
Valeria Scafidi ◽  
Marta Di Carlo
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Permeability Transition ◽  
Mitochondrial Protein ◽  
Radical Scavenging ◽  
Permeability Transition ◽  
Oxidation Potential ◽  
Mitochondrial Functions

Mitochondria are dynamic ATP-generating organelle which contribute to many cellular functions including bioenergetics processes, intracellular calcium regulation, alteration of reduction-oxidation potential of cells, free radical scavenging, and activation of caspase mediated cell death. Mitochondrial functions can be negatively affected by amyloidβpeptide (Aβ), an important component in Alzheimer’s disease (AD) pathogenesis, and Aβcan interact with mitochondria and cause mitochondrial dysfunction. One of the most accepted hypotheses for AD onset implicates that mitochondrial dysfunction and oxidative stress are one of the primary events in the insurgence of the pathology. Here, we examine structural and functional mitochondrial changes in presence of Aβ. In particular we review data concerning Aβimport into mitochondrion and its involvement in mitochondrial oxidative stress, bioenergetics, biogenesis, trafficking, mitochondrial permeability transition pore (mPTP) formation, and mitochondrial protein interaction. Moreover, the development of AD therapy targeting mitochondria is also discussed.

scholarly journals Tau-mediated Disruption of the Spliceosome Triggers Cryptic RNA-splicing and Neurodegeneration in Alzheimer’s Disease

2019 ◽  
Author(s):  
Yi-Chen Hsieh ◽  
Caiwei Guo ◽  
Hari K. Yalamanchili ◽  
Measho Abreha ◽  
Rami Al-Ouran ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Rna Splicing ◽  
Intron Retention ◽  
Neurofibrillary Tangle ◽  
Neuronal Loss ◽  
Mrna Splicing ◽  
Postmortem Brain ◽  
Loss Of Function ◽  
Human Postmortem Brain

SUMMARYIn Alzheimer’s disease (AD), spliceosomal proteins with critical roles in RNA processing aberrantly aggregate and mislocalize to Tau neurofibrillary tangles. We test the hypothesis that Tau-spliceosome interactions disrupt pre-mRNA splicing in AD. In human postmortem brain with AD pathology, Tau coimmunoprecipitates with spliceosomal core components. In Drosophila models, pan-neuronal Tau expression triggers reductions in core and U1-specific spliceosomal proteins, and genetic disruption of these factors, including SmB, U1-70K, and U1A, enhances Tau-mediated neurodegeneration. We further show that loss-of-function in SmB, encoding a core spliceosomal protein, causes decreased survival, progressive locomotor impairment, and neuronal loss, independent of Tau toxicity. Lastly, RNA-sequencing reveals a similar profile of mRNA splicing errors in SmB mutant and Tau transgenic flies, including intron retention and non-annotated cryptic splice junctions. In human brains, we confirm cryptic splicing errors in association with neurofibrillary tangle pathologic burden. Our results implicate spliceosome disruption and perturbations of the neuronal transcriptome in Tau-mediated neurodegeneration in AD.

scholarly journals Altered synaptic ingestion by human microglia in Alzheimer’s disease

2019 ◽  
Author(s):  
Makis Tzioras ◽  
Michael J.D. Daniels ◽  
Declan King ◽  
Karla Popovic ◽  
Rebecca K. Holloway ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Brain ◽  
Mouse Models ◽  
Disease Risk ◽  
Synaptic Proteins ◽  
Postmortem Brain ◽  
Human Microglia ◽  
Human Postmortem Brain ◽  
Synapse Loss

AbstractSynapse loss correlates strongly with cognitive decline in Alzheimer’s disease, but the mechanisms underpinning this phenomenon remain unclear. Recent evidence from mouse models points to microglial cells as mediators of synapse removal, and human genetic evidence implicates microglia in disease risk. Here we demonstrate that microglia from human postmortem brain contain synaptic proteins and that greater amounts are observed in microglia from Alzheimer’s compared to non-diseased brain tissue. Further, we observe that primary human adult microglia phagocytose synapses isolated from human brain, and that AD brain-derived synapses are phagocytosed more rapidly and abundantly than controls. Together, these data show that synapses in the human AD brain are more prone to ingestion by microglia. Our findings provide evidence from human tissue implicating altered microglial-mediated synaptic uptake in AD pathobiology.One Sentence SummaryAD alters synapse ingestion by microglia

PINK1 Activation Attenuates Impaired Neuronal-Like Differentiation and Synaptogenesis and Mitochondrial Dysfunction in Alzheimer’s Disease Trans-Mitochondrial Cybrid Cells

2021 ◽  
pp. 1-13
Author(s):  
Fang Du ◽  
Qing Yu ◽  
Shirley ShiDu Yan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Energy Homeostasis ◽  
Early Stage ◽  
Mitochondrial Morphology ◽  
Mitochondrial Functions ◽  
Lentivirus Transduction ◽  
And Function ◽  
Human Brains

Background: Mitochondrial dysfunction, bioenergetic deficit, and extensive oxidative stress underlie neuronal perturbation during the early stage of Alzheimer’s disease (AD). Previously, we demonstrated that decreased PTEN-induced putative kinase 1 (PINK1) expression is associated with AD pathology in AD-affected human brains and AD mice. Objective: In the present study, we highlight the essential role of PINK1 in AD-relevant mitochondrial perturbation and neuronal malfunction. Methods: Using trans-mitochondrial “cybrid” (cytoplasmic hybrid) neuronal cells, whose mitochondria are transferred from platelets of patients with sporadic AD, we observed the effect of PINK1 in neuronal-like differentiation and synaptogenesis and mitochondrial functions. Results: In AD cybrid cells, the downregulation of PINK1 is correlated to the alterations in mitochondrial morphology and function and deficit in neuronal-like differentiation. Restoring/increasing PINK1 by lentivirus transduction of PINK1 robustly attenuate mitochondrial defects and rescue neurite-like outgrowth. Importantly, defective PINK1 kinase activity fails to reverse these detrimental effects. Mechanistically, AD cybrid cells reveal a significant decrease in PINK1-dependent phosphorylated mitofusin (Mfn) 2, a key mitochondrial membrane protein that participates in mitochondrial fusion, and an insufficient autophagic activity for clearance of dysfunctional mitochondria. Overexpression of PINK1, but not mutant PINK1 elevates phosphorylation of Mfn2 and autophagy signaling LC3-II. Accordingly, PINK1-overexpressed AD cybrids exhibit increases in mitochondrial length and density and suppressed reactive oxygen species. These results imply that activation of PINK1 protects against AD-affected mitochondrial dysfunction and impairment in neuronal maturation and differentiation. Conclusion: PINK1-mediated mitophagy is important for maintaining mitochondrial health by clearance of dysfunctional mitochondria and therefore, improves energy homeostasis in AD.

SPECIFIC PROPERTIES OF TUBULIN IN THE PREFRONTAL CORTEX IN CONTROL, SCHIZOPHRENIA AND VASCULAR DEMENTIA

2020 ◽  
pp. 65-71
Author(s):  
Burbaeva G.Sh. ◽  
Androsova L.V. ◽  
Vorobyeva E.A. ◽  
Savushkina O.K.
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Prefrontal Cortex ◽  
Vascular Dementia ◽  
Binding Activity ◽  
Nephelometric Method ◽  
Rate Of Polymerization ◽  
Mental Diseases ◽  
And Control ◽  
The Brain

The aim of the study was to evaluate the rate of polymerization of tubulin into microtubules and determine the level of colchicine binding (colchicine-binding activity of tubulin) in the prefrontal cortex in schizophrenia, vascular dementia (VD) and control. Colchicine-binding activity of tubulin was determined by Sherlinе in tubulin-enriched extracts of proteins from the samples. Measurement of light scattering during the polymerization of the tubulin was carried out using the nephelometric method at a wavelength of 450-550 nm. There was a significant decrease in colchicine-binding activity and the rate of tubulin polymerization in the prefrontal cortex in both diseases, and in VD to a greater extent than in schizophrenia. The obtained results suggest that not only in Alzheimer's disease, but also in other mental diseases such as schizophrenia and VD, there is a decrease in the level of tubulin in the prefrontal cortex of the brain, although to a lesser extent than in Alzheimer's disease, and consequently the amount of microtubules.

scholarly journals Mitochondrial complex I abnormalities is associated with tau and clinical symptoms in mild Alzheimer’s disease

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Tatsuhiro Terada ◽  
Joseph Therriault ◽  
Min Su Peter Kang ◽  
Melissa Savard ◽  
Tharick Ali Pascoal ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Complex I ◽  
Clinical Symptoms ◽  
Mitochondrial Complex I ◽  
Braak Stage ◽  
Mitochondrial Complex ◽  
Temporal Area

Abstract Background Mitochondrial electron transport chain abnormalities have been reported in postmortem pathological specimens of Alzheimer’s disease (AD). However, it remains unclear how amyloid and tau are associated with mitochondrial dysfunction in vivo. The purpose of this study is to assess the local relationships between mitochondrial dysfunction and AD pathophysiology in mild AD using the novel mitochondrial complex I PET imaging agent [18F]BCPP-EF. Methods Thirty-two amyloid and tau positive mild stage AD dementia patients (mean age ± SD: 71.1 ± 8.3 years) underwent a series of PET measurements with [18F]BCPP-EF mitochondrial function, [11C]PBB3 for tau deposition, and [11C] PiB for amyloid deposition. Age-matched normal control subjects were also recruited. Inter and intrasubject comparisons of levels of mitochondrial complex I activity, amyloid and tau deposition were performed. Results The [18F]BCPP-EF uptake was significantly lower in the medial temporal area, highlighting the importance of the mitochondrial involvement in AD pathology. [11C]PBB3 uptake was greater in the temporo-parietal regions in AD. Region of interest analysis in the Braak stage I-II region showed significant negative correlation between [18F]BCPP-EF SUVR and [11C]PBB3 BPND (R = 0.2679, p = 0.04), but not [11C] PiB SUVR. Conclusions Our results indicated that mitochondrial complex I is closely associated with tau load evaluated by [11C]PBB3, which might suffer in the presence of its off-target binding. The absence of association between mitochondrial complex I dysfunction with amyloid load suggests that mitochondrial dysfunction in the trans-entorhinal and entorhinal region is a reflection of neuronal injury occurring in the brain of mild AD.

scholarly journals Distinct network topology in Alzheimer’s disease and behavioral variant frontotemporal dementia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Adeline Su Lyn Ng ◽  
Juan Wang ◽  
Kwun Kei Ng ◽  
Joanna Su Xian Chong ◽  
Xing Qian ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Frontotemporal Dementia ◽  
Network Topology ◽  
Neuropsychiatric Symptoms ◽  
Brain Network ◽  
Salience Network ◽  
Behavioral Variant Frontotemporal Dementia ◽  
Control Networks ◽  
And Control

Abstract Background Alzheimer’s disease (AD) and behavioral variant frontotemporal dementia (bvFTD) cause distinct atrophy and functional disruptions within two major intrinsic brain networks, namely the default network and the salience network, respectively. It remains unclear if inter-network relationships and whole-brain network topology are also altered and underpin cognitive and social–emotional functional deficits. Methods In total, 111 participants (50 AD, 14 bvFTD, and 47 age- and gender-matched healthy controls) underwent resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessments. Functional connectivity was derived among 144 brain regions of interest. Graph theoretical analysis was applied to characterize network integration, segregation, and module distinctiveness (degree centrality, nodal efficiency, within-module degree, and participation coefficient) in AD, bvFTD, and healthy participants. Group differences in graph theoretical measures and empirically derived network community structures, as well as the associations between these indices and cognitive performance and neuropsychiatric symptoms, were subject to general linear models, with age, gender, education, motion, and scanner type controlled. Results Our results suggested that AD had lower integration in the default and control networks, while bvFTD exhibited disrupted integration in the salience network. Interestingly, AD and bvFTD had the highest and lowest degree of integration in the thalamus, respectively. Such divergence in topological aberration was recapitulated in network segregation and module distinctiveness loss, with AD showing poorer modular structure between the default and control networks, and bvFTD having more fragmented modules in the salience network and subcortical regions. Importantly, aberrations in network topology were related to worse attention deficits and greater severity in neuropsychiatric symptoms across syndromes. Conclusions Our findings underscore the reciprocal relationships between the default, control, and salience networks that may account for the cognitive decline and neuropsychiatric symptoms in dementia.

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