scholarly journals Iron-loading is a prominent feature of activated microglia in Alzheimer’s disease patients

2021 ◽  
Author(s):  
Boyd Kenkhuis ◽  
Antonios Somarakis ◽  
Lorraine de Haan ◽  
Oleh Dzyubachyk ◽  
Marieke E IJsselsteijn ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Iron Loading ◽  
Brain Iron ◽  
Disease Pathogenesis ◽  
Analysis Pipeline ◽  
Iron Storage ◽  
Activated Microglia ◽  
Key Players ◽  
Functional Phenotype ◽  
Iron Storage Protein

AbstractBrain iron accumulation has been found to accelerate disease progression in Amyloid β-positive Alzheimer patients, though the mechanism is still unknown. Microglia have been identified as key-players in the disease pathogenesis, and are highly reactive cells responding to aberrations such as increased iron levels. Therefore, using histological methods, multispectral immunofluorescence and an automated in-house developed microglia segmentation and analysis pipeline, we studied the occurrence of iron-accumulating microglia and the effect on its activation state in human Alzheimer brains. We identified a subset of microglia with increased expression of the iron storage protein ferritin light chain (FTL), together with increased Iba1 expression, decreased TMEM119 and P2RY12 expression. This activated microglia subset represented iron-accumulating microglia and appeared morphologically dystrophic. Multispectral immunofluorescence allowed for spatial analysis of FTL+Iba1+-microglia, which were found to be the predominant Aβ-plaque infiltrating microglia. Finally, an increase of FTL+Iba1+-microglia was seen in patients with high Amyloid-β load and Tau load. These findings suggest iron to be taken up by microglia and to influence the functional phenotype of these cells, especially in conjunction with Aβ.

scholarly journals Iron loading is a prominent feature of activated microglia in Alzheimer’s disease patients

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Boyd Kenkhuis ◽  
Antonios Somarakis ◽  
Lorraine de Haan ◽  
Oleh Dzyubachyk ◽  
Marieke E. IJsselsteijn ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Iron Loading ◽  
Brain Iron ◽  
Disease Pathogenesis ◽  
Analysis Pipeline ◽  
Iron Storage ◽  
Activated Microglia ◽  
Key Players ◽  
Functional Phenotype ◽  
Iron Storage Protein

AbstractBrain iron accumulation has been found to accelerate disease progression in amyloid-β(Aβ) positive Alzheimer patients, though the mechanism is still unknown. Microglia have been identified as key players in the disease pathogenesis, and are highly reactive cells responding to aberrations such as increased iron levels. Therefore, using histological methods, multispectral immunofluorescence and an automated in-house developed microglia segmentation and analysis pipeline, we studied the occurrence of iron-accumulating microglia and the effect on its activation state in human Alzheimer brains. We identified a subset of microglia with increased expression of the iron storage protein ferritin light chain (FTL), together with increased Iba1 expression, decreased TMEM119 and P2RY12 expression. This activated microglia subset represented iron-accumulating microglia and appeared morphologically dystrophic. Multispectral immunofluorescence allowed for spatial analysis of FTL+Iba1+-microglia, which were found to be the predominant Aβ-plaque infiltrating microglia. Finally, an increase of FTL+Iba1+-microglia was seen in patients with high Aβ load and Tau load. These findings suggest iron to be taken up by microglia and to influence the functional phenotype of these cells, especially in conjunction with Aβ.

scholarly journals Fe(II) formation after interaction of the amyloid β-peptide with iron-storage protein ferritin

2018 ◽  
Vol 44 (3) ◽  
pp. 237-243 ◽  
Author(s):  
Lucia Balejcikova ◽  
Katarina Siposova ◽  
Peter Kopcansky ◽  
Ivo Safarik
Keyword(s):  
Storage Protein ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Iron Storage ◽  
Iron Storage Protein

scholarly journals CD63 is Regulated by Iron via the IRE-IRP System and is Important for Ferritin Secretion by Extracellular Vesicles

Blood ◽  
2021 ◽  
Author(s):  
Izumi Yanatori ◽  
Des R Richardson ◽  
Herschel Shrikant Dhekne ◽  
Shinya Toyokuni ◽  
Fumio Kishi
Keyword(s):  
Extracellular Vesicles ◽  
Storage Protein ◽  
Regulatory Protein ◽  
Iron Loading ◽  
Nuclear Receptor Coactivator ◽  
Iron Storage ◽  
Cellular Iron ◽  
Associated Proteins ◽  
Responsive Element ◽  
Iron Storage Protein

Extracellular vesicles (EVs) transfer functional molecules between cells. CD63 is a widely recognized EV marker that contributes to EV secretion from cells. However, the regulation of its expression remains largely unknown. Ferritin is a cellular iron storage protein that can be also secreted by the exosome pathway (Truman-Rosentsvit M. et al. BLOOD 131 (2018) 342-352), with serum ferritin levels classically reflecting body iron stores. Iron metabolism-associated proteins, such as ferritin, are intricately regulated by cellular iron levels via the iron responsive element (IRE)-iron regulatory protein (IRP) system. Herein, we present a novel mechanism demonstrating that the expression of the EV-associated protein, CD63, is under the regulation of the IRE-IRP system. We discovered a canonical IRE in the 5'-untranslated region (UTR) of CD63 mRNA responsible for regulating its expression in response to increased iron. Cellular iron-loading caused a marked increase in CD63 expression and the secretion from cells of CD63 positive (i.e., CD63(+)) EVs, which were shown to contain ferritin-H (FtH) and -L (FtL). Our results demonstrate that under iron-loading, intracellular ferritin is transferred via nuclear receptor coactivator 4 (NCOA4) to CD63(+) EVs that are then secreted. Such iron-regulated secretion of the major iron storage protein ferritin via CD63(+) EVs, poses significant impact for understanding the local cell-to-cell exchange of ferritin and iron.

Polygonal profiles of ferritin molecules

1983 ◽  
Vol 41 ◽  
pp. 600-601
Author(s):  
William H. Massover
Keyword(s):  
Axial Ratio ◽  
X Ray Diffraction ◽  
Rhombic Dodecahedron ◽  
Apparent Contradiction ◽  
Iron Storage ◽  
X Ray ◽  
Hexagonal Shape ◽  
Axes Of Symmetry ◽  
Apparent Conflict ◽  
Iron Storage Protein

The molecular structure of the iron-storage protein, ferritin, is becoming known in ever finer detail. The 24 apoferritin subunits (MW ca. 20,000) have a 2:1 axial ratio and are polymerized with 4:3:2 symmetry to form an outer shell surrounding a variable amount of microcrystalline iron, Recent x-ray diffraction results indicate that the projected outline of the native molecule has a quasi-hexagonal shape when viewed down the 3-fold axes of symmetry, and a quasi-square shape when looking down the 4-fold axes. To date, no electron microscope study has reported observing anything other than circular profiles, which would indicate that ferritin is strictly spherical. The apparent conflict between the "hollow sphere" of electron microscopy (E.M.) and the "truncated rhombic dodecahedron" of x-ray diffraction could reflect the poorer effective resolution of E.M. coming from radiation damage, staining, drying, etc. The present study investigates the detailed shape of individual ferritin molecules in order to search for the predicted aspherical profiles and to interpret the nature of this apparent contradiction.

Insights into amyloid disease from fly models

2014 ◽  
Vol 56 ◽  
pp. 69-83 ◽  
Author(s):  
Ko-Fan Chen ◽  
Damian C. Crowther
Keyword(s):  
Drosophila Melanogaster ◽  
Neurodegenerative Disorders ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Disease Pathogenesis ◽  
Amyloid Aggregates ◽  
Aβ Amyloid ◽  
Polypeptide Chains ◽  
Amyloid Diseases

The formation of amyloid aggregates is a feature of most, if not all, polypeptide chains. In vivo modelling of this process has been undertaken in the fruitfly Drosophila melanogaster with remarkable success. Models of both neurological and systemic amyloid diseases have been generated and have informed our understanding of disease pathogenesis in two main ways. First, the toxic amyloid species have been at least partially characterized, for example in the case of the Aβ (amyloid β-peptide) associated with Alzheimer's disease. Secondly, the genetic underpinning of model disease-linked phenotypes has been characterized for a number of neurodegenerative disorders. The current challenge is to integrate our understanding of disease-linked processes in the fly with our growing knowledge of human disease, for the benefit of patients.

scholarly journals Neuroinflammation and protein pathology in Parkinson’s disease dementia

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Antonina Kouli ◽  
Marta Camacho ◽  
Kieren Allinson ◽  
Caroline H. Williams-Gray
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
T Lymphocytes ◽  
Substantia Nigra ◽  
Amyloid Β ◽  
Brain Regions ◽  
Parkinson’S Disease Dementia ◽  
Activated Microglia ◽  
Cell Counts ◽  
The Brain

AbstractParkinson’s disease dementia is neuropathologically characterized by aggregates of α-synuclein (Lewy bodies) in limbic and neocortical areas of the brain with additional involvement of Alzheimer’s disease-type pathology. Whilst immune activation is well-described in Parkinson’s disease (PD), how it links to protein aggregation and its role in PD dementia has not been explored. We hypothesized that neuroinflammatory processes are a critical contributor to the pathology of PDD. To address this hypothesis, we examined 7 brain regions at postmortem from 17 PD patients with no dementia (PDND), 11 patients with PD dementia (PDD), and 14 age and sex-matched neurologically healthy controls. Digital quantification after immunohistochemical staining showed a significant increase in the severity of α-synuclein pathology in the hippocampus, entorhinal and occipitotemporal cortex of PDD compared to PDND cases. In contrast, there was no difference in either tau or amyloid-β pathology between the groups in any of the examined regions. Importantly, we found an increase in activated microglia in the amygdala of demented PD brains compared to controls which correlated significantly with the extent of α-synuclein pathology in this region. Significant infiltration of CD4+ T lymphocytes into the brain parenchyma was commonly observed in PDND and PDD cases compared to controls, in both the substantia nigra and the amygdala. Amongst PDND/PDD cases, CD4+ T cell counts in the amygdala correlated with activated microglia, α-synuclein and tau pathology. Upregulation of the pro-inflammatory cytokine interleukin 1β was also evident in the substantia nigra as well as the frontal cortex in PDND/PDD versus controls with a concomitant upregulation in Toll-like receptor 4 (TLR4) in these regions, as well as the amygdala. The evidence presented in this study show an increased immune response in limbic and cortical brain regions, including increased microglial activation, infiltration of T lymphocytes, upregulation of pro-inflammatory cytokines and TLR gene expression, which has not been previously reported in the postmortem PDD brain.

Analysis of Iron in Ferritin, the Iron-Storage Protein: A General Chemistry Experiment

1998 ◽  
Vol 75 (4) ◽  
pp. 437 ◽  
Author(s):  
Maureen J. Donlin ◽  
Regina F. Frey ◽  
Christopher Putnam ◽  
Jody Proctor ◽  
James K. Bashkin
Keyword(s):  
General Chemistry ◽  
Storage Protein ◽  
Protein A ◽  
Iron Storage ◽  
Chemistry Experiment ◽  
Iron Storage Protein

scholarly journals Preparation of platinum nanoparticles using iron(ii) as reductant and photosensitized H2 generation on an iron storage protein scaffold

RSC Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 5551-5559
Author(s):  
Brenda S. Benavides ◽  
Silvano Valandro ◽  
Donald M. Kurtz
Keyword(s):  
Heavy Chain ◽  
Platinum Nanoparticles ◽  
Storage Protein ◽  
Iron Storage ◽  
Protein Scaffold ◽  
H2 Generation ◽  
Iron Storage Protein

An assembly of platinum nanoparticles produced by Fe(ii) reduction of Pt(ii) and stabilized by human heavy chain ferritin's native catalysis of Fe(ii)(aq) autoxidation functions as an efficient photosensitized H2 evolution catalyst.

scholarly journals High Dietary Iron Disrupts Iron Homeostasis and Induces Amyloid-β and Phospho-τ Expression in the Hippocampus of Adult Wild-Type and APP/PS1 Transgenic Mice

2019 ◽  
Vol 149 (12) ◽  
pp. 2247-2254 ◽  
Author(s):  
Min Chen ◽  
Jiashuo Zheng ◽  
Guohao Liu ◽  
Chong Zeng ◽  
En Xu ◽  
...  
Keyword(s):  
Cognitive Function ◽  
Transgenic Mice ◽  
Iron Homeostasis ◽  
Iron Concentration ◽  
Amyloid Β ◽  
Dietary Iron ◽  
Wild Type ◽  
Brain Iron ◽  
Sod Activity ◽  
The Impact

ABSTRACT Background Brain iron deposition is a feature of Alzheimer disease and may contribute to its development. However, the relative contribution of dietary iron remains unclear. Objectives We investigated the impact of high dietary iron on brain pathological changes and cognitive function in adult wild-type (WT) mice and amyloid precursor protein/presenilin 1 (APP/PS1) double transgenic mice. Methods Male WT mice and APP/PS1 mice aged 10 wk were fed either a control diet (66 mg Fe/kg) (WT-Ctrl and APP/PS1-Ctrl) or a high iron diet (14 g Fe/kg) (WT-High Fe and APP/PS1-High Fe) for 20 wk. Iron concentrations in brain regions were measured by atomic absorption spectrophotometry. Brain iron staining and amyloid-β (Aβ) immunostaining were performed. Protein expressions in the hippocampus were determined by immunoblotting. Superoxide dismutase (SOD) activity and malondialdehyde concentration were examined. Cognitive functions were tested with the Morris water maze system. Results In the hippocampus, APP/PS1-High Fe mice had significantly higher iron concentration (2.5-fold) and ferritin (2.0-fold) than APP/PS1-Ctrl mice (P < 0.001), and WT-High Fe mice had significantly higher ferritin (2.0-fold) than WT-Ctrl mice (P < 0.001). Interestingly, APP/PS1 mice had significantly higher iron concentration (2–3-fold) and ferritin (2–2.5-fold) than WT mice fed either diet (P < 0.001). Histological analysis indicated that iron accumulated in the hippocampal dentate gyrus region in APP/PS1 mice, consistent with the pattern of Aβ deposition. For both mouse strains, iron treatment induced Aβ and phospho-τ expression (1.5–3-fold) in the hippocampus, but had little impact on oxidative stress and cognitive function. Furthermore, APP/PS1 mice had significantly lower SOD activity and higher malondialdehyde concentration than WT mice in the hippocampus (P < 0.0001), paralleled by apparent cognitive dysfunction. Conclusions Dietary iron overload induces iron disorder and Aβ and phospho-τ expression in the hippocampus of adult WT and APP/PS1 transgenic mice.

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