scholarly journals Linking lipids, Alzheimer's and LXRs?

2004 ◽  
Vol 2 (1) ◽  
pp. nrs.02001 ◽  
Author(s):  
Nilay V. Patel ◽  
Barry Marc Forman
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Pathology ◽  
Liver X Receptor ◽  
Therapeutic Strategies ◽  
Cholesterol Homeostasis ◽  
Aβ Peptide ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Aβ Production

Deposition of the β-amyloid (Aβ) peptide is thought to underlie development of Alzheimer's disease (AD). This pathological linkage has spurred considerable interest in therapeutic strategies to reduce Aβ production. It is becoming increasingly clear that altered cholesterol homeostasis can modulate Aβ production and/or accumulation. In this review, we discuss the molecular pathology of AD, the cholesterol connection and recent data suggesting that the oxysterol receptor, liver X receptor LXR (NR1H2 and NR1H3), may modulate these events.

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.

Current theories for the molecular and cellular pathogenesis of Alzheimer's disease

2001 ◽  
Vol 3 (16) ◽  
pp. 1-11 ◽  
Author(s):  
Gunnar K. Gouras
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Process ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Cellular Pathogenesis ◽  
Amyloid Cascade ◽  
The Brain ◽  
Aβ Production ◽  
Prevailing View

Over the past decade, the prevailing view for the molecular and cellular pathogenesis of Alzheimer's disease (AD) has centred on the β-amyloid (Aβ) peptide that accumulates in vulnerable brain areas in the disease. The amyloid cascade hypothesis postulates that the build up of Aβ in the brain causes damage to neurons, leading to dysfunction and loss of neurons, and the clinical phenotype of the amnestic dementia characteristic of AD. All known mutations that result in autosomal dominant forms of early-onset familial AD cause increased production of Aβ42, a form of Aβ that is particularly relevant in AD. Other proteins that are crucial to the pathogenesis of AD are the presenilins 1 and 2, which are intimately involved with Aβ production and when mutated in familial forms of AD cause increases in Aβ42. Currently, challenges in AD research include determining the earliest pathological effects of Aβ42, how the important AD risk factor apolipoprotein E affects the disease process, whether presenilin is the elusive γ-secretase, and how levels of Aβ can be effectively reduced therapeutically.

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 Macroautophagy—a novel β-amyloid peptide-generating pathway activated in Alzheimer's disease

2005 ◽  
Vol 171 (1) ◽  
pp. 87-98 ◽  
Author(s):  
W. Haung Yu ◽  
Ana Maria Cuervo ◽  
Asok Kumar ◽  
Corrinne M. Peterhoff ◽  
Stephen D. Schmidt ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Survival ◽  
Mammalian Target Of Rapamycin ◽  
Amyloid Peptide ◽  
Survival Pathways ◽  
Secretase Activity ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Β Amyloid Peptide

Macroautophagy, which is a lysosomal pathway for the turnover of organelles and long-lived proteins, is a key determinant of cell survival and longevity. In this study, we show that neuronal macroautophagy is induced early in Alzheimer's disease (AD) and before β-amyloid (Aβ) deposits extracellularly in the presenilin (PS) 1/Aβ precursor protein (APP) mouse model of β-amyloidosis. Subsequently, autophagosomes and late autophagic vacuoles (AVs) accumulate markedly in dystrophic dendrites, implying an impaired maturation of AVs to lysosomes. Immunolabeling identifies AVs in the brain as a major reservoir of intracellular Aβ. Purified AVs contain APP and β-cleaved APP and are highly enriched in PS1, nicastrin, and PS-dependent γ-secretase activity. Inducing or inhibiting macroautophagy in neuronal and nonneuronal cells by modulating mammalian target of rapamycin kinase elicits parallel changes in AV proliferation and Aβ production. Our results, therefore, link β-amyloidogenic and cell survival pathways through macroautophagy, which is activated and is abnormal in AD.

scholarly journals Neuronal aging potentiates beta-amyloid generation via amyloid precursor protein endocytosis

2019 ◽  
Author(s):  
Tatiana Burrinha ◽  
Ricardo Gomes ◽  
Ana Paula Terrasso ◽  
Cláudia Guimas Almeida
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Precursor Protein ◽  
Precursor Protein ◽  
App Processing ◽  
Early Endosomes ◽  
Primary Mouse ◽  
Β Amyloid ◽  
Aβ Production

AbstractAging increases the risk of Alzheimer’s disease (AD). During normal aging synapses decline and β-Amyloid (Aβ) accumulates. An Aβ defective clearance with aging is postulated as responsible for Aβ accumulation, although a role for increased Aβ production with aging can also lead to Aβ accumulation. To test this hypothesis, we established a long-term culture of primary mouse neurons that mimics neuronal aging (lysosomal lipofuscin accumulation and synapse decline). Intracellular endogenous Aβ42 accumulated in aged neurites due to increased amyloid-precursor protein (APP) processing. We show that APP processing is up-regulated by a specific age-dependent increase in APP endocytosis. Endocytosed APP accumulated in early endosomes that, in turn were found augmented in aged neurites. APP processing and early endosomes up-regulation was recapitulated in vivo. Finally, we found that inhibition of Aβ production reduced the decline in synapses in aged neurons. We propose that potentiation of APP endocytosis by neuronal aging increases Aβ production, which contributes to aging-dependent decline in synapses.SummaryHow aging increases the risk of Alzheimer’s disease is not clear. We show that normal neuronal aging increases the intracellular production of β-amyloid, due to an upregulation of the amyloid precursor protein endocytosis. Importantly, increased Aβ production contributes to the aging-dependent synapse loss.

Distance-based β-amyloid protein detection on PADs for scanning and subsequent follow up of Alzheimer’s disease in human urine sample

The Analyst ◽  
2022 ◽  
Author(s):  
Kawin Khachornsakkul ◽  
Anongnat Tiangtrong ◽  
Araya Suwannasom ◽  
Wuttichai Sangkharoek ◽  
Opor Jamjumrus ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Urine ◽  
Protein Detection ◽  
Protein Quantification ◽  
Amyloid Protein ◽  
Human Urine Sample ◽  
Amyloid Aβ ◽  
Β Amyloid

We report on the first development of a simple distance-based β-amyloid (Aβ) protein quantification using paper-based devices (dPADs) to screen for Alzheimer’s disease (AD) and to subsequently follow up on...

scholarly journals Noncanonical function of an autophagy protein prevents spontaneous Alzheimer’s disease

2020 ◽  
Vol 6 (33) ◽  
pp. eabb9036
Author(s):  
Bradlee L. Heckmann ◽  
Brett J. W. Teubner ◽  
Emilio Boada-Romero ◽  
Bart Tummers ◽  
Clifford Guy ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Human Disease ◽  
Memory Impairment ◽  
Memory Loss ◽  
Tau Hyperphosphorylation ◽  
Primary Microglia ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Old Mice

Noncanonical functions of autophagy proteins have been implicated in neurodegenerative conditions, including Alzheimer’s disease (AD). The WD domain of the autophagy protein Atg16L is dispensable for canonical autophagy but required for its noncanonical functions. Two-year-old mice lacking this domain presented with robust β-amyloid (Aβ) pathology, tau hyperphosphorylation, reactive microgliosis, pervasive neurodegeneration, and severe behavioral and memory deficiencies, consistent with human disease. Mechanistically, we found this WD domain was required for the recycling of Aβ receptors in primary microglia. Pharmacologic suppression of neuroinflammation reversed established memory impairment and markers of disease pathology in this novel AD model. Therefore, loss of the Atg16L WD domain drives spontaneous AD in mice, and inhibition of neuroinflammation is a potential therapeutic approach for treating neurodegeneration and memory loss. A decline in expression of ATG16L in the brains of human patients with AD suggests the possibility that a similar mechanism may contribute in human disease.

scholarly journals Imbalance of Endocannabinoid/Lysophosphatidylinositol Receptors Marks the Severity of Alzheimer’s Disease in a Preclinical Model: A Therapeutic Opportunity

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 377
Author(s):  
Dina Medina-Vera ◽  
Cristina Rosell-Valle ◽  
Antonio J. López-Gambero ◽  
Juan A. Navarro ◽  
Emma N. Zambrana-Infantes ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Receptor Expression ◽  
Preclinical Model ◽  
Diacylglycerol Lipase ◽  
Therapeutic Opportunity ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
5Xfad Mice ◽  
Old Mice

Alzheimer’s disease (AD) is the most common form of neurodegeneration and dementia. The endocannabinoid (ECB) system has been proposed as a novel therapeutic target to treat AD. The present study explores the expression of the ECB system, the ECB-related receptor GPR55, and cognitive functions (novel object recognition; NOR) in the 5xFAD (FAD: family Alzheimer’s disease) transgenic mouse model of AD. Experiments were performed on heterozygous (HTZ) and homozygous (HZ) 11 month old mice. Protein expression of ECB system components, neuroinflammation markers, and β-amyloid (Aβ) plaques were analyzed in the hippocampus. According to the NOR test, anxiety-like behavior and memory were altered in both HTZ and HZ 5xFAD mice. Furthermore, both animal groups displayed a reduction of cannabinoid (CB1) receptor expression in the hippocampus, which is related to memory dysfunction. This finding was associated with indirect markers of enhanced ECB production, resulting from the combination of impaired monoacylglycerol lipase (MAGL) degradation and increased diacylglycerol lipase (DAGL) levels, an effect observed in the HZ group. Regarding neuroinflammation, we observed increased levels of CB2 receptors in the HZ group that positively correlate with Aβ’s accumulation. Moreover, HZ 5xFAD mice also exhibited increased expression of the GPR55 receptor. These results highlight the importance of the ECB signaling for the AD pathogenesis development beyond Aβ deposition.

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