Live cell imaging of single neurotrophin receptor molecules on human neuron in Alzheimer’s disease

AbstractThe changes in the receptor dynamics such as the surface movement of the receptor molecules on the plasma membrane are essential to receptor function. However, whether the receptor dynamics are affected by disease conditions is unknown. Neurotrophin receptors such as TrkA and p75NTR play a critical role in neuronal survival and their functions are highly affected in Alzheimer’s disease (AD). Using live-cell single-molecule imaging of neurotrophin receptors we examined the surface trafficking of TrKA and p75NTR molecules on human induced pluripotent stem cells (hiPSCs) derived live neurons from presenilin 1 (PSEN1) mutant AD patients and healthy subjects. Here we report that surface trafficking of p75NTR molecules on neurites is faster than that of TrkA molecules in healthy controls. The surface dynamics of TrkA molecules were elevated in AD patients compared to healthy individuals. In contrast, the surface movement of p75NTR was significantly smaller in AD patients compared to healthy individuals. Interestingly, amyloid beta1-42 (Aβ1-42) administration increased the surface trafficking of both TrkA and p75NTR in healthy hiPSCs neurons. These findings provides the first evidence that the surface diffusion of TrkA and p75NTR molecules are altered in patients suffering from AD. Our data also suggest that Aβ1-42 may responsible for the alteration of the surface movements of TrkA but not for p75NTR.One Sentence SummaryThe surface movements of neurotrophin receptors such as TrkA and p75NTR are altered in neurons derived from patients suffering from familial Alzheimer’s disease.

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Live-Cell Imaging of Single Neurotrophin Receptor Molecules on Human Neurons in Alzheimer’s Disease

International Journal of Molecular Sciences ◽

10.3390/ijms222413260 ◽

2021 ◽

Vol 22 (24) ◽

pp. 13260

Author(s):

Klaudia Barabás ◽

Julianna Kobolák ◽

Soma Godó ◽

Tamás Kovács ◽

Dávid Ernszt ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Single Molecule ◽

Critical Role ◽

Live Cell ◽

Neurotrophin Receptor ◽

P75 Neurotrophin Receptor ◽

Surface Movement ◽

Human Neurons ◽

Receptor Dynamics

Neurotrophin receptors such as the tropomyosin receptor kinase A receptor (TrkA) and the low-affinity binding p75 neurotrophin receptor p75NTR play a critical role in neuronal survival and their functions are altered in Alzheimer’s disease (AD). Changes in the dynamics of receptors on the plasma membrane are essential to receptor function. However, whether receptor dynamics are affected in different pathophysiological conditions is unexplored. Using live-cell single-molecule imaging, we examined the surface trafficking of TrkA and p75NTR molecules on live neurons that were derived from human-induced pluripotent stem cells (hiPSCs) of presenilin 1 (PSEN1) mutant familial AD (fAD) patients and non-demented control subjects. Our results show that the surface movement of TrkA and p75NTR and the activation of TrkA- and p75NTR-related phosphoinositide-3-kinase (PI3K)/serine/threonine-protein kinase (AKT) signaling pathways are altered in neurons that are derived from patients suffering from fAD compared to controls. These results provide evidence for altered surface movement of receptors in AD and highlight the importance of investigating receptor dynamics in disease conditions. Uncovering these mechanisms might enable novel therapies for AD.

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Cerebellar Calcium-Binding Protein and Neurotrophin Receptor Defects in Down Syndrome and Alzheimer's Disease

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.645334 ◽

2021 ◽

Vol 13 ◽

Author(s):

Jennifer C. Miguel ◽

Sylvia E. Perez ◽

Michael Malek-Ahmadi ◽

Elliott J. Mufson

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Down Syndrome ◽

Calcium Binding ◽

Critical Role ◽

Neurotrophin Receptor ◽

Strong Negative Correlation ◽

Brush Cells ◽

Plaque Load ◽

Calbindin D

Cerebellar hypoplasia is a major characteristic of the Down syndrome (DS) brain. However, the consequences of trisomy upon cerebellar Purkinje cells (PC) and interneurons in DS are unclear. The present study performed a quantitative and qualitative analysis of cerebellar neurons immunostained with antibodies against calbindin D-28k (Calb), parvalbumin (Parv), and calretinin (Calr), phosphorylated and non-phosphorylated intermediate neurofilaments (SMI-34 and SMI-32), and high (TrkA) and low (p75NTR) affinity nerve growth factor (NGF) receptors as well as tau and amyloid in DS (n = 12), Alzheimer's disease (AD) (n = 10), and healthy non-dementia control (HC) (n = 8) cases. Our findings revealed higher Aβ42 plaque load in DS compared to AD and HC but no differences in APP/Aβ plaque load between HC, AD, and DS. The cerebellar cortex neither displayed Aβ40 containing plaques nor pathologic phosphorylated tau in any of the cases examined. The number and optical density (OD) measurements of Calb immunoreactive (-ir) PC soma and dendrites were similar between groups, while the number of PCs positive for Parv and SMI-32 were significantly reduced in AD and DS compared to HC. By contrast, the number of SMI-34-ir PC dystrophic axonal swellings, termed torpedoes, was significantly greater in AD compared to DS. No differences in SMI-32- and Parv-ir PC OD measurements were observed between groups. Conversely, total number of Parv- (stellate/basket) and Calr (Lugaro, brush, and Golgi)-positive interneurons were significantly reduced in DS compared to AD and HC. A strong negative correlation was found between counts for Parv-ir interneurons, Calr-ir Golgi and brush cells, and Aβ42 plaque load. Number of TrkA and p75NTR positive PCs were reduced in AD compared to HC. These findings suggest that disturbances in calcium binding proteins play a critical role in cerebellar neuronal dysfunction in adults with DS.

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Loss of ferroportin induces memory impairment by promoting ferroptosis in Alzheimer’s disease

Cell Death and Differentiation ◽

10.1038/s41418-020-00685-9 ◽

2021 ◽

Author(s):

Wen-Dai Bao ◽

Pei Pang ◽

Xiao-Ting Zhou ◽

Fan Hu ◽

Wan Xiong ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Memory Impairment ◽

Iron Homeostasis ◽

Critical Role ◽

Gene Set Enrichment Analysis ◽

Molecular Characteristics ◽

Intracellular Iron

AbstractIron homeostasis disturbance has been implicated in Alzheimer’s disease (AD), and excess iron exacerbates oxidative damage and cognitive defects. Ferroptosis is a nonapoptotic form of cell death dependent upon intracellular iron. However, the involvement of ferroptosis in the pathogenesis of AD remains elusive. Here, we report that ferroportin1 (Fpn), the only identified mammalian nonheme iron exporter, was downregulated in the brains of APPswe/PS1dE9 mice as an Alzheimer’s mouse model and Alzheimer’s patients. Genetic deletion of Fpn in principal neurons of the neocortex and hippocampus by breeding Fpnfl/fl mice with NEX-Cre mice led to AD-like hippocampal atrophy and memory deficits. Interestingly, the canonical morphological and molecular characteristics of ferroptosis were observed in both Fpnfl/fl/NEXcre and AD mice. Gene set enrichment analysis (GSEA) of ferroptosis-related RNA-seq data showed that the differentially expressed genes were highly enriched in gene sets associated with AD. Furthermore, administration of specific inhibitors of ferroptosis effectively reduced the neuronal death and memory impairments induced by Aβ aggregation in vitro and in vivo. In addition, restoring Fpn ameliorated ferroptosis and memory impairment in APPswe/PS1dE9 mice. Our study demonstrates the critical role of Fpn and ferroptosis in the progression of AD, thus provides promising therapeutic approaches for this disease.

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Differential diagnosis of Alzheimer’s disease using spectrochemical analysis of blood

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1701517114 ◽

2017 ◽

Vol 114 (38) ◽

pp. E7929-E7938 ◽

Cited By ~ 56

Author(s):

Maria Paraskevaidi ◽

Camilo L. M. Morais ◽

Kássio M. G. Lima ◽

Julie S. Snowden ◽

Jennifer A. Saxon ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neurodegenerative Diseases ◽

Sensitivity And Specificity ◽

Lewy Bodies ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Repeated Measurements ◽

Healthy Individuals ◽

Different Types

The progressive aging of the world’s population makes a higher prevalence of neurodegenerative diseases inevitable. The necessity for an accurate, but at the same time, inexpensive and minimally invasive, diagnostic test is urgently required, not only to confirm the presence of the disease but also to discriminate between different types of dementia to provide the appropriate management and treatment. In this study, attenuated total reflection FTIR (ATR-FTIR) spectroscopy combined with chemometric techniques were used to analyze blood plasma samples from our cohort. Blood samples are easily collected by conventional venepuncture, permitting repeated measurements from the same individuals to monitor their progression throughout the years or evaluate any tested drugs. We included 549 individuals: 347 with various neurodegenerative diseases and 202 age-matched healthy individuals. Alzheimer’s disease (AD;n= 164) was identified with 70% sensitivity and specificity, which after the incorporation of apolipoprotein ε4 genotype (APOEε4) information, increased to 86% when individuals carried one or two alleles of ε4, and to 72% sensitivity and 77% specificity when individuals did not carry ε4 alleles. Early AD cases (n= 14) were identified with 80% sensitivity and 74% specificity. Segregation of AD from dementia with Lewy bodies (DLB;n= 34) was achieved with 90% sensitivity and specificity. Other neurodegenerative diseases, such as frontotemporal dementia (FTD;n= 30), Parkinson’s disease (PD;n= 32), and progressive supranuclear palsy (PSP;n= 31), were included in our cohort for diagnostic purposes. Our method allows for both rapid and robust diagnosis of neurodegeneration and segregation between different dementias.

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The APOE ε4/ε4 Genotype Potentiates Vascular Fibrin(Ogen) Deposition in Amyloid-Laden Vessels in the Brains of Alzheimer's Disease Patients

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2013.76 ◽

2013 ◽

Vol 33 (8) ◽

pp. 1251-1258 ◽

Cited By ~ 71

Author(s):

Karin Hultman ◽

Sidney Strickland ◽

Erin H Norris

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Critical Role ◽

Apoe Genotype ◽

Postmortem Brain ◽

Amyloid Angiopathy ◽

Apoe Ε4 ◽

Cerebrovascular Dysfunction ◽

Postmortem Brain Tissue ◽

Clotting Protein

Evidence indicates a critical role for cerebrovascular dysfunction in Alzheimer's disease (AD) pathophysiology. We have shown that fibrin(ogen), the principal blood-clotting protein, is deposited in the AD neurovasculature and interacts with beta-amyloid (Ab), resulting in increased formation of blood clots. As apolipoprotein E (ApoE), a lipid-transporting protein with three human isoforms (E2, E3, and E4), also binds to Aβ, we hypothesized that ApoE and fibrin(ogen) may have a combined effect on the vascular pathophysiology in AD. We assessed whether APOE genotype differentially influences vascular fibrin(ogen) deposition in postmortem brain tissue using immunohistochemistry. An increased deposition of fibrin(ogen) was observed in AD cases compared with non-demented controls, and there was a strong correlation between cerebral amyloid angiopathy (CAA) severity and fibrin(ogen) deposition. Moreover, brains from AD cases homozygous for APOE ε4 showed increased deposition of fibrin(ogen), specifically in CAA- and oligomeric Aβ-positive vessels compared with AD APOE ε2 and ε3 allele carriers, an effect that was not directly linked to CAA severity and cerebrovascular atherosclerosis. These data further support a role for fibrin(ogen) in AD pathophysiology and link the APOE ε4/ε4 genotype with increased thrombosis and/or impaired fibrinolysis in the human AD brain.

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Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer’s Disease

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.703876 ◽

2021 ◽

Vol 13 ◽

Author(s):

Jose L. Martinez ◽

Matthew D. Zammit ◽

Nicole R. West ◽

Bradley T. Christian ◽

Anita Bhattacharyya

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Down Syndrome ◽

Basal Forebrain ◽

Critical Role ◽

Memory Loss ◽

Cholinergic Neurons ◽

Cholinergic Innervation ◽

Attention And Memory ◽

Basal Forebrain Cholinergic Neurons

Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer’s disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.

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Implication of exosomes derived from cholesterol-accumulated astrocytes in Alzheimer's disease pathology

Disease Models & Mechanisms ◽

10.1242/dmm.048929 ◽

2021 ◽

Author(s):

Qi Wu ◽

Leonardo Cortez ◽

Razieh Kamali-Jamil ◽

Valerie Sim ◽

Holger Wille ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Influence Function ◽

Critical Role ◽

Amyloid Β ◽

Cholesterol Accumulation ◽

Aβ Peptides ◽

Neuronal Viability ◽

Cultured Astrocytes ◽

Aβ Production

Amyloid β (Aβ) peptides generated from the amyloid precursor protein (APP) play a critical role in the development of Alzheimer's disease (AD) pathology. Aβ-containing neuronal exosomes, which represent a novel form of intercellular communication, have been shown to influence function/vulnerability of neurons in AD. Unlike neurons, the significance of exosomes derived from astrocytes remains unclear. In this study, we evaluated the significance of exosomes derived from U18666A-induced cholesterol-accumulated astrocytes in the development of AD pathology. Our results show that cholesterol accumulation decreases exosome secretion, whereas lowering cholesterol level increases exosome secretion from cultured astrocytes. Interestingly, exosomes secreted from U18666A-treated astrocytes contain higher levels of APP, APP-CTFs, soluble APP, APP secretases and Aβ1-40 than exosomes secreted from control astrocytes. Furthermore, we show that exosomes derived from U18666A-treated astrocytes can lead to neurodegeneration, which is attenuated by decreasing Aβ production or by neutralizing exosomal Aβ peptide with an Aβ antibody. These results, taken together, suggest that exosomes derived from cholesterol-accumulated astrocytes can play an important role in trafficking APP/Aβ peptides and influencing neuronal viability in the affected regions of the AD brain.

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Blocking microglial activation of reactive astrocytes is neuroprotective in models of Alzheimer’s disease

Acta Neuropathologica Communications ◽

10.1186/s40478-021-01180-z ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Jong-Sung Park ◽

Tae-In Kam ◽

Saebom Lee ◽

Hyejin Park ◽

Yumin Oh ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neurodegenerative Disorders ◽

Critical Role ◽

Subcutaneous Administration ◽

Reactive Astrocytes ◽

Reactive Astrocyte ◽

Spatial Learning And Memory ◽

Neuronal Viability ◽

Age Related

AbstractAlzheimer’s disease (AD) is the most common cause of age-related dementia. Increasing evidence suggests that neuroinflammation mediated by microglia and astrocytes contributes to disease progression and severity in AD and other neurodegenerative disorders. During AD progression, resident microglia undergo proinflammatory activation, resulting in an increased capacity to convert resting astrocytes to reactive astrocytes. Therefore, microglia are a major therapeutic target for AD and blocking microglia-astrocyte activation could limit neurodegeneration in AD. Here we report that NLY01, an engineered exedin-4, glucagon-like peptide-1 receptor (GLP-1R) agonist, selectively blocks β-amyloid (Aβ)-induced activation of microglia through GLP-1R activation and inhibits the formation of reactive astrocytes as well as preserves neurons in AD models. In two transgenic AD mouse models (5xFAD and 3xTg-AD), repeated subcutaneous administration of NLY01 blocked microglia-mediated reactive astrocyte conversion and preserved neuronal viability, resulting in improved spatial learning and memory. Our study indicates that the GLP-1 pathway plays a critical role in microglia-reactive astrocyte associated neuroinflammation in AD and the effects of NLY01 are primarily mediated through a direct action on Aβ-induced GLP-1R+ microglia, contributing to the inhibition of astrocyte reactivity. These results show that targeting upregulated GLP-1R in microglia is a viable therapy for AD and other neurodegenerative disorders.

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