scholarly journals The Effect of the APOE4 Gene on Accumulation of Aβ 40 After Brain Injury Cannot Be Reversed by Increasing apoE4 Protein

2016 ◽  
Vol 75 (8) ◽  
pp. 770-778 ◽  
Author(s):  
Patricia M. Washington ◽  
Mark P. Burns
Keyword(s):  
Brain Injury ◽  
Amyloid Precursor Protein Processing ◽  
Biphasic Response ◽  
Protein Levels ◽  
Abnormal Accumulation ◽  
Apoe Protein ◽  
Rapid Clearance ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain

Abstract The apolipoprotein E (apoE) protein is involved in clearance of β-amyloid (Aβ) from the brain; and the APOE4 gene is associated with Aβ plaque formation in humans following traumatic brain injury (TBI). Here, we examined the association between apoE and Aβ 40 after experimental TBI and the effects of APOE alleles on this relationship. We report a biphasic response of soluble apoE protein after TBI with an acute reduction at 1 day postinjury followed by an increase at 7 days postinjury. TBI-induced Aβ 40 levels decreased as soluble apoE levels increased. In APOE4 mice there was a diminished apoE response to TBI that corresponded to prolonged accumulation of TBI-induced Aβ 40 versus that in APOE3 mice. Amyloid precursor protein processing was similar in APOE3 and APOE4 mice suggesting that impaired clearance was responsible for the abnormal accumulation of Aβ 40 in the latter. Treatment of APOE4 mice with bexarotene for 7 days increased apoE4 protein levels but was not sufficient to reduce TBI-induced Aβ 40 . Thus, rapid clearance of TBI-induced Aβ 40 occurs in mice but these pathways are impaired in APOE4 carriers. These data may help explain the deposition of Aβ in APOE4 carriers and the increased incidence of brain Aβ plaques following TBI.

MiR-335-5p Inhibits β-Amyloid (Aβ) Accumulation to Attenuate Cognitive Deficits Through Targeting c-jun-N-terminal Kinase 3 in Alzheimer’s Disease

2020 ◽  
Vol 17 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Dan Wang ◽  
Zhifu Fei ◽  
Song Luo ◽  
Hai Wang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transgenic Mice ◽  
Western Blot ◽  
Mrna Expression ◽  
Cognitive Deficits ◽  
Protein Levels ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Relationship

Objectives: Alzheimer's disease (AD), also known as senile dementia, is a common neurodegenerative disease characterized by progressive cognitive impairment and personality changes. Numerous evidences have suggested that microRNAs (miRNAs) are involved in the pathogenesis and development of AD. However, the exact role of miR-335-5p in the progression of AD is still not clearly clarified. Methods: The protein and mRNA levels were measured by western blot and RNA extraction and quantitative real-time PCR (qRT-PCR), respectively. The relationship between miR-335-5p and c-jun-N-terminal kinase 3 (JNK3) was confirmed by dual-luciferase reporter assay. SH-SY5Y cells were transfected with APP mutant gene to establish the in vitro AD cell model. Flow cytometry and western blot were performed to evaluate cell apoptosis. The APP/PS1 transgenic mice were used as an in vivo AD model. Morris water maze test was performed to assess the effect of miR- 335-5p on the cognitive deficits in APP/PS1 transgenic mice. Results: The JNK3 mRNA expression and protein levels of JNK3 and β-Amyloid (Aβ) were significantly up-regulated, and the mRNA expression of miR-335-5p was down-regulated in the brain tissues of AD patients. The expression levels of miR-335-5p and JNK3 were significantly inversely correlated. Further, the dual Luciferase assay verified the relationship between miR-335- 5p and JNK3. Overexpression of miR-335-5p significantly decreased the protein levels of JNK3 and Aβ and inhibited apoptosis in SH-SY5Y/APPswe cells, whereas the inhibition of miR-335-5p obtained the opposite results. Moreover, the overexpression of miR-335-5p remarkably improved the cognitive abilities of APP/PS1 mice. Conclusion: The results revealed that the increased JNK3 expression, negatively regulated by miR-335-5p, may be a potential mechanism that contributes to Aβ accumulation and AD progression, indicating a novel approach for AD treatment.

scholarly journals Changes in expression of GFAP, ApoE and APP mRNA and protein levels in the adult rat brain following cortical injury

2013 ◽  
Vol 65 (1) ◽  
pp. 255-264
Author(s):  
Natasa Loncarevic-Vasiljkovic ◽  
Vesna Pesic ◽  
N. Tanic ◽  
Desanka Milanovic ◽  
Aleksandra Mladenovic-Djordjevic ◽  
...  
Keyword(s):  
Brain Plasticity ◽  
Recovery Period ◽  
Potential Contribution ◽  
Cortical Injury ◽  
Adult Rat ◽  
Protein Levels ◽  
Adult Rat Brain ◽  
Apoe Protein ◽  
The Brain

The recovery period following cortical injury (CI) is characterized by a dynamic and highly complex interplay between beneficial and detrimental events. The aim of this study was to examine the expressions of Glial Fibrillary Acidic Protein (GFAP), Apolipoprotein E (ApoE) and Amyloid Precursor Protein (APP), all of which are involved in brain plasticity and neurodegeneration. Our results reveal that CI strongly influenced GFAP, ApoE and APP mRNA expression, as well as GFAP and ApoE protein expression. Considering the pivotal role of these proteins in the brain, the obtained results point to their potential contribution in neurodegeneration and consequent Alzheimer?s disease development.

scholarly journals Editorial for the Genetics of Alzheimer’s Disease Special Issue: October 2021

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1794
Author(s):  
Laura Ibanez ◽  
Justin B. Miller
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gray Matter ◽  
Neuronal Death ◽  
Tau Proteins ◽  
Special Issue ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain

Alzheimer’s disease is a complex and multifactorial condition regulated by both genetics and lifestyle, which ultimately results in the accumulation of β-amyloid (Aβ) and tau proteins in the brain, loss of gray matter, and neuronal death [...]

scholarly journals Substrate-Specific Activation of α-Secretase by 7-Deoxy-Trans-Dihydronarciclasine Increases Non-Amyloidogenic Processing of β-Amyloid Protein Precursor

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 646
Author(s):  
Yoon Sun Chun ◽  
Yoon Young Cho ◽  
Oh Hoon Kwon ◽  
Dong Zhao ◽  
Hyun Ok Yang ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Protein Precursor ◽  
App Processing ◽  
Plot Analysis ◽  
Amyloidogenic Processing ◽  
Model Mouse ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain ◽  
Aβ Production

Accumulation of β-amyloid (Aβ) in the brain has been implicated in the pathology of Alzheimer’s disease (AD). Aβ is produced from the Aβ precursor protein (APP) through the amyloidogenic pathway by β-, and γ-secretase. Alternatively, APP can be cleaved by α-, and γ-secretase, precluding the production of Aβ. Thus, stimulating α-secretase mediated APP processing is considered a therapeutic option not only for decreasing Aβ production but for increasing neuroprotective sAPPα. We have previously reported that 7-deoxy-trans-dihydronarciclasine (E144), the active component of Lycoris chejuensis, decreases Aβ production by attenuating APP level, and retarding APP maturation. It can also improve cognitive function in the AD model mouse. In this study, we further analyzed the activating effect of E144 on α-secretase. Treatment of E144 increased sAPPα, but decreased β-secretase products from HeLa cells stably transfected with APP. E144 directly activated ADAM10 and ADAM17 in a substrate-specific manner both in cell-based and in cell-free assays. The Lineweaver–Burk plot analysis revealed that E144 enhanced the affinities of A Disintegrin and Metalloproteinases (ADAMs) towards the substrate. Consistent with this result, immunoprecipitation analysis showed that interactions of APP with ADAM10 and ADAM17 were increased by E144. Our results indicate that E144 might be a novel agent for AD treatment as a substrate-specific activator of α-secretase.

scholarly journals Transmissible Endosomal Intoxication: A Balance between Exosomes and Lysosomes at the Basis of Intercellular Amyloid Propagation

Biomedicines ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 272
Author(s):  
Anaïs Bécot ◽  
Charlotte Volgers ◽  
Guillaume van Niel
Keyword(s):  
Amyloid Precursor Protein ◽  
Neurodegenerative Diseases ◽  
Multivesicular Body ◽  
Precursor Protein ◽  
Aβ Peptides ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Novel Concept ◽  
The Brain

In Alzheimer′s disease (AD), endolysosomal dysfunctions are amongst the earliest cellular features to appear. Each organelle of the endolysosomal system, from the multivesicular body (MVB) to the lysosome, contributes to the homeostasis of amyloid precursor protein (APP) cleavage products including β-amyloid (Aβ) peptides. Hence, this review will attempt to disentangle how changes in the endolysosomal system cumulate to the generation of toxic amyloid species and hamper their degradation. We highlight that the formation of MVBs and the generation of amyloid species are closely linked and describe how the molecular machineries acting at MVBs determine the generation and sorting of APP cleavage products towards their degradation or release in association with exosomes. In particular, we will focus on AD-related distortions of the endolysomal system that divert it from its degradative function to favour the release of exosomes and associated amyloid species. We propose here that such an imbalance transposed at the brain scale poses a novel concept of transmissible endosomal intoxication (TEI). This TEI would initiate a self-perpetuating transmission of endosomal dysfunction between cells that would support the propagation of amyloid species in neurodegenerative diseases.

scholarly journals Pharmacogenetic features of cathepsin B inhibitors that improve memory deficit and reduce β-amyloid related to Alzheimer's disease

2010 ◽  
Vol 391 (8) ◽  
Author(s):  
Vivian Hook ◽  
Gregory Hook ◽  
Mark Kindy
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Models ◽  
Cathepsin B ◽  
Memory Deficit ◽  
Mutant Site ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain ◽  
Aβ Production

Abstract Beta-amyloid (Aβ) in the brain is a major factor involved in Alzheimer's disease (AD) that results in severe memory deficit. Our recent studies demonstrate pharmacogenetic differences in the effects of inhibitors of cathepsin B to improve memory and reduce Aβ in different mouse models of AD. The inhibitors improve memory and reduce brain Aβ in mice expressing the wild-type (WT) β-secretase site of human APP, expressed in most AD patients. However, these inhibitors have no effect in mice expressing the rare Swedish (Swe) mutant amyloid precursor protein (APP). Knockout of the cathepsin B decreased brain Aβ in mice expressing WT APP, validating cathepsin B as the target. The specificity of cathepsin B to cleave the WT β-secretase site, but not the Swe mutant site, of APP for Aβ production explains the distinct inhibitor responses in the different AD mouse models. In contrast to cathepsin B, the BACE1 β-secretase prefers to cleave the Swe mutant site. Discussion of BACE1 data in the field indicate that they do not preclude cathepsin B as also being a β-secretase. Cathepsin B and BACE1 could participate jointly as β-secretases. Significantly, the majority of AD patients express WT APP and, therefore, inhibitors of cathepsin B represent candidate drugs for AD.

Detection of β-amyloid oligomers as a predictor of neurological outcome after brain injury

2013 ◽  
Vol 118 (6) ◽  
pp. 1336-1342 ◽  
Author(s):  
Joshua Wayne Gatson ◽  
Victoria Warren ◽  
Kareem Abdelfattah ◽  
Steven Wolf ◽  
Linda S. Hynan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Brain Injury ◽  
High Molecular Weight ◽  
Enzyme Linked Immunosorbent Assay ◽  
Neurological Outcomes ◽  
Amyloid Oligomers ◽  
Scale Scores ◽  
Csf Levels ◽  
Β Amyloid ◽  
The Brain

Object Traumatic brain injury (TBI) is known to be a risk factor for Alzheimer-like dementia. In previous studies, an increase in β-amyloid (Aβ) monomers, such as β-amyloid 42 (Aβ42), in the CSF of patients with TBI has been shown to correlate with a decrease in amyloid plaques in the brain and improved neurological outcomes. In this study, the authors hypothesized that the levels of toxic high-molecular-weight β-amyloid oligomers are increased in the brain and are detectable within the CSF of TBI patients with poor neurological outcomes. Methods Samples of CSF were collected from 18 patients with severe TBI (Glasgow Coma Scale Scores 3–8) and a ventriculostomy. In all cases the CSF was collected within 72 hours of injury. The CSF levels of neuron-specific enolase (NSE) and Aβ42 were measured using enzyme-linked immunosorbent assay. The levels of high-molecular-weight β-amyloid oligomers were measured using Western blot analysis. Results Patients with good outcomes showed an increase in the levels of CSF Aβ42 (p = 0.003). Those with bad outcomes exhibited an increase in CSF levels of β-amyloid oligomers (p = 0.009) and NSE (p = 0.001). In addition, the CSF oligomer levels correlated with the scores on the extended Glasgow Outcome Scale (r = −0.89, p = 0.0001), disability rating scale scores (r = 0.77, p = 0.005), CSF Aβ42 levels (r = −0.42, p = 0.12), and CSF NSE levels (r = 0.70, p = 0.004). Additionally, the receiver operating characteristic curve yielded an area under the curve for β-amyloid oligomers of 0.8750 ± 0.09. Conclusions Detection of β-amyloid oligomers may someday become a useful clinical tool for determining injury severity and neurological outcomes in patients with TBI.

scholarly journals Reduced Levels of ABCA1 Transporter Are Responsible for the Cholesterol Efflux Impairment in β-Amyloid-Induced Reactive Astrocytes: Potential Rescue from Biomimetic HDLs

2021 ◽  
Vol 23 (1) ◽  
pp. 102
Author(s):  
Giulia Sierri ◽  
Roberta Dal Magro ◽  
Barbara Vergani ◽  
Biagio Eugenio Leone ◽  
Beatrice Formicola ◽  
...  
Keyword(s):  
Cholesterol Efflux ◽  
Brain Parenchyma ◽  
Reactive Astrocytes ◽  
Cholesterol Transport ◽  
Functional Changes ◽  
Atp Binding Cassette Transporters ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
The Brain

The cerebral synthesis of cholesterol is mainly handled by astrocytes, which are also responsible for apoproteins’ synthesis and lipoproteins’ assembly required for the cholesterol transport in the brain parenchyma. In Alzheimer disease (AD), these processes are impaired, likely because of the astrogliosis, a process characterized by morphological and functional changes in astrocytes. Several ATP-binding cassette transporters expressed by brain cells are involved in the formation of nascent discoidal lipoproteins, but the effect of beta-amyloid (Aβ) assemblies on this process is not fully understood. In this study, we investigated how of Aβ1-42-induced astrogliosis affects the metabolism of cholesterol in vitro. We detected an impairment in the cholesterol efflux of reactive astrocytes attributable to reduced levels of ABCA1 transporters that could explain the decreased lipoproteins’ levels detected in AD patients. To approach this issue, we designed biomimetic HDLs and evaluated their performance as cholesterol acceptors. The results demonstrated the ability of apoA-I nanodiscs to cross the blood–brain barrier in vitro and to promote the cholesterol efflux from astrocytes, making them suitable as a potential supportive treatment for AD to compensate the depletion of cerebral HDLs.

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