scholarly journals Monitoring phagocytic uptake of amyloid β into glial cell lysosomes in real time

2021 ◽  
Author(s):  
Priya Prakash ◽  
Krupal P. Jethava ◽  
Nils Korte ◽  
Pablo Izquierdo ◽  
Emilia Favuzzi ◽  
...  
Keyword(s):  
Real Time ◽  
Brain Tissue ◽  
Glial Cell ◽  
Amyloid Β ◽  
Tissue Sections ◽  
Health And Disease ◽  
Ph Dependent ◽  
Phagocytic Uptake

Glial cell phagocytosis of pH-dependent amyloid-β, AβpH, in live and fixed cultures, brain tissue sections, retina, cortex and in live animals useful for studying function in health and disease.

A pH-dependent conformational transition of Aβ peptide and physicochemical properties of the conformers in the glial cell

2002 ◽  
Vol 361 (3) ◽  
pp. 547-556 ◽  
Author(s):  
Yoichi MATSUNAGA ◽  
Nobuhiro SAITO ◽  
Akihiro FUJII ◽  
Junichi YOKOTANI ◽  
Tadakazu TAKAKURA ◽  
...  
Keyword(s):  
Glial Cell ◽  
Conformational Changes ◽  
Conformational Transition ◽  
Early Stage ◽  
Ph Dependence ◽  
Amyloid Β ◽  
Proteinase K ◽  
Aβ Peptide ◽  
Ph Dependent ◽  
Insight Into

In the present study we identified the epitopes of antibodies against amyloid β-(1–42)-peptide (Aβ1–42): 4G8 reacted with peptides corresponding to residues 17–21, 6F/3D reacted with peptides corresponding to residues 9–14, and anti 5-10 reacted with peptides corresponding to residues 5–10. The study also yielded some insight into the Aβ1–42 structures resulting from differences in pH. An ELISA study using monoclonal antibodies showed that pH-dependent conformational changes occur in the 6F/3D and 4G8 epitopes modified at pH 4.6, but not in the sequences recognized by anti 1-7 and anti 5-10. This was unique to Aβ1–40 and Aβ1–42 and did not occur with Aβ1–16 or Aβ17–42. The reactivity profile of 4G8 was not affected by blockage of histidine residues of pH-modified Aβ1–40 and Aβ1–42 with diethyl pyrocarbonate; however, the mutant [Gln11]Aβ1–40 abrogated the unique pH-dependence towards 4G8 observed with Aβ1–40. These findings suggest that these epitopes are cryptic at pH4.6, and that Glu11 is responsible for the changes. We suggest that the abnormal folding of 6F/3D epitope affected by pH masked the 4G8 epitope. A study of the binding of metal ions to Aβ1–42 suggested that Cu2+ and Zn2+ induced a conformational transition around the 6F/3D region at pH7.4, but did not affect the region when it was modified at pH4.6. However, Fe2+ had no effect, irrespective of pH. Aβ modified at pH 4.6 appeared to be relatively resistant to proteinase K compared with Aβs modified at pH7.4, and the former might be preferentially internalized and accumulated in a human glial cell. Our findings suggest the importance of microenvironmental changes, such as pH, in the early stage of formation of Aβ aggregates in the glial cell.

scholarly journals Cerebral amyloid angiopathy severity is linked to dilation of juxtacortical perivascular spaces

2015 ◽  
Vol 36 (3) ◽  
pp. 576-580 ◽  
Author(s):  
Susanne J van Veluw ◽  
Geert Jan Biessels ◽  
Willem H Bouvy ◽  
Wim GM Spliet ◽  
Jaco JM Zwanenburg ◽  
...  
Keyword(s):  
Cerebral Amyloid Angiopathy ◽  
Small Vessel Disease ◽  
Amyloid Β ◽  
Amyloid Angiopathy ◽  
Perivascular Spaces ◽  
Resonance Imaging ◽  
Centrum Semiovale ◽  
Tissue Sections ◽  
Cortical Areas ◽  
Cerebral Amyloid

Perivascular spaces are an emerging marker of small vessel disease. Perivascular spaces in the centrum semiovale have been associated with cerebral amyloid angiopathy. However, a direct topographical relationship between dilated perivascular spaces and cerebral amyloid angiopathy severity has not been established. We examined this association using post-mortem magnetic resonance imaging in five cases with evidence of cerebral amyloid angiopathy pathology. Juxtacortical perivascular spaces dilation was evaluated on T2 images and related to cerebral amyloid angiopathy severity in overlying cortical areas on 34 tissue sections stained for Amyloid β. Degree of perivascular spaces dilation was significantly associated with cerebral amyloid angiopathy severity (odds ratio = 3.3, 95% confidence interval 1.3–7.9, p = 0.011). Thus, dilated juxtacortical perivascular spaces are a promising neuroimaging marker of cerebral amyloid angiopathy severity.

Visualisation of GABAergic neurons and synapses in the rat brain using immunohistochemistry for two forms of glutamate decarboxylase

2021 ◽  
Vol 21 (2) ◽  
pp. 63-73
Author(s):  
Valeria A. Razenkova ◽  
Dmitrii E. Korzhevskii
Keyword(s):  
Brain Tissue ◽  
Glutamate Decarboxylase ◽  
Brain Structures ◽  
Gabaergic Neurons ◽  
Laboratory Animals ◽  
Tissue Samples ◽  
Tissue Sections ◽  
Background Staining ◽  
The Central Nervous System ◽  
Rat Forebrain

BACKGROUND: Taking into account the importance of GABAergic brain system research and also the opportunity to achieve specific and accurate results in laboratory studies using immunohistochemical approaches, it seems important to have a reliable method of visualization GABA-synthesizing cells, their projections and synapses, for the morphofunctional analysis of GABAergic system both in normal conditions and in the experimental pathology. AIM: The aim of the study was to visualize analyze GABAergic neurons and synapses within rats brain using three different antibody types against glutamate decarboxylase and to identify the optimal conditions for reaction performing. MATERIALS AND METHODS: The study was performed on paraffin brain tissue sections of 5 adult Wistar rats. Immunohistochemical reactions using three antibody types against glutamate decarboxylase isoform 67 (GAD67) and glutamate decarboxylase isoform 65 (GAD65) were performed. Additional controls on C57/Bl6 mice and Chinchilla rabbits brain samples were also carried out. RESULTS: Antibodies used in the research made it possible to achieve high quality of GABAergic structures visualizing without increasing background staining. At the same time different antibody types are distinct in their efficacy to perform immunohistochemistry reaction on laboratory animal brain tissue samples. By performing additional controls, we discovered that there is necessary to adsorb secondary reagents immunoglobulins in order to eliminate nonspecific staining. It was found that GAD67 and GAD65 distribution in rat forebrain structures is different. It was stated that GAD67 immunohistochemistry most completely reveals GABAergic brain structures compared to GAD65 immunhistochemistry. The possibility of determining morphological features of GABAergic neurons and synaptic terminals, as well as performing quantitative analysis, was demonstrated. CONCLUSIONS: The approach proposed makes it possible to specifically visualize GABAergic structures of the central nervous system of different laboratory animals. This could be useful both in fundamental studies and in pathology research.

scholarly journals Detection and characterisation of papillomavirus in skin lesions of giraffe and sable antelope in South Africa

2011 ◽  
Vol 82 (2) ◽  
Author(s):  
E. Van Dyk ◽  
A-M Bosman ◽  
E. Van Wilpe ◽  
J. H. Williams ◽  
R. G. Bengis ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Skin Lesions ◽  
Immunoperoxidase Staining ◽  
Bovine Papillomavirus ◽  
Virus Particles ◽  
Tissue Sections ◽  
Equine Sarcoid ◽  
Pcr Product ◽  
Papillomavirus Dna

Papillomavirus was detected electron microscopically in cutaneous fibropapillomas of a giraffe (Giraffa camelopardalis) and a sable antelope (Hippotragus niger). The virus particles measured 45 nm in diameter. Histopathologically, the lesions showed histopathological features similar to those of equine sarcoid as well as positive immunoperoxidase-staining of tissue sections for papillomavirus antigen. Polymerase chain reaction (PCR) detected bovine papillomavirus (BPV) DNA. Bovine papillomavirus-1 was characterised by real-time PCR in the sable and giraffe, and cloning and sequencing of the PCR product revealed a similarity to BPV-1. As in the 1st giraffe, the lesions from a 2nd giraffe revealed locally malignant pleomorphism, possibly indicating the lesional end-point of papilloma infection. Neither virus particles nor positively staining papillomavirus antigen could be demonstrated in the 2nd giraffe but papillomavirus DNA was detected by real-time PCR which corresponded with BPV-1 and BPV-2.

scholarly journals Borrelia burgdorferi Co-Localizing with Amyloid Markers in Alzheimer’s Disease Brain Tissues

2021 ◽  
pp. 1-15
Author(s):  
Alireza G. Senejani ◽  
Jasmin Maghsoudlou ◽  
Dina El-Zohiry ◽  
Gauri Gaur ◽  
Keith Wawrzeniak ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Neurodegenerative Diseases ◽  
Amyloid Β ◽  
Tau Proteins ◽  
Tissue Sections ◽  
Mammalian Cell Lines ◽  
Parkinson’S Diseases ◽  
Relationship Of ◽  
Brain Tissues

Background: Infections by bacterial or viral agents have been hypothesized to influence the etiology of neurodegenerative diseases. Objective: This study examined the potential presence of Borrelia burgdorferi spirochete, the causative agent of Lyme disease, in brain autopsy tissue of patients diagnosed with either Alzheimer’s (AD) or Parkinson’s diseases. Methods: Brain tissue sections from patients with age-matched controls were evaluated for antigen and DNA presence of B. burgdorferi using various methods. Positive Borrelia structures were evaluated for co-localization with biofilm and AD markers such as amyloid and phospho-tau (p-Tau) using immunohistochemical methods. Results: The results showed the presence of B. burgdorferi antigen and DNA in patients with AD pathology and among those, one of them was previously diagnosed with Lyme disease. Interestingly, a significant number of Borrelia-positive aggregates with a known biofilm marker, alginate, were found along with the spirochetal structures. Our immunohistochemical data also showed that Borrelia-positive aggregates co-localized with amyloid and anti-phospho-tau markers. To further prove the potential relationship of B. burgdorferi and amyloids, we infected two mammalian cell lines with B. burgdorferi which resulted in a significant increase in the expression of amyloid-β and p-Tau proteins in both cells lines post-infection. Conclusion: These results indicate that B. burgdorferi can be found in AD brain tissues, not just in spirochete but a known antibiotics resistant biofilm form, and its co-localized amyloid markers. In summary, this study provides evidence for a likely association between B. burgdorferi infections and biofilm formation, AD pathology, and chronic neurodegenerative diseases.

scholarly journals Elevated Expression of MiR-17 in Microglia of Alzheimer’s Disease Patients Abrogates Autophagy-Mediated Amyloid-β Degradation

2021 ◽  
Vol 12 ◽  
Author(s):  
Shady Estfanous ◽  
Kylene P. Daily ◽  
Mostafa Eltobgy ◽  
Nicholas P. Deems ◽  
Midhun N. K. Anne ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Therapeutic Interventions ◽  
Tissue Sections ◽  
Cargo Receptor ◽  
5Xfad Mouse ◽  
Aβ Degradation

Autophagy is a proposed route of amyloid-β (Aβ) clearance by microglia that is halted in Alzheimer’s Disease (AD), though mechanisms underlying this dysfunction remain elusive. Here, primary microglia from adult AD (5xFAD) mice were utilized to demonstrate that 5xFAD microglia fail to degrade Aβ and express low levels of autophagy cargo receptor NBR1. In 5xFAD mouse brains, we show for the first time that AD microglia express elevated levels of microRNA cluster Mirc1/Mir17-92a, which is known to downregulate autophagy proteins. By in situ hybridization in post-mortem AD human tissue sections, we observed that the Mirc1/Mir17-92a cluster member miR-17 is also elevated in human AD microglia, specifically in the vicinity of Aβ deposits, compared to non-disease controls. We show that NBR1 expression is negatively correlated with expression of miR-17 in human AD microglia via immunohistopathologic staining in human AD brain tissue sections. We demonstrate in healthy microglia that autophagy cargo receptor NBR1 is required for Aβ degradation. Inhibiting elevated miR-17 in 5xFAD mouse microglia improves Aβ degradation, autophagy, and NBR1 puncta formation in vitro and improves NBR1 expression in vivo. These findings offer a mechanism behind dysfunctional autophagy in AD microglia which may be useful for therapeutic interventions aiming to improve autophagy function in AD.

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