Lipoprotein-Based Nanoparticles Rescue the Memory Loss of Mice with Alzheimer’s Disease by Accelerating the Clearance of Amyloid-Beta

ACS Nano ◽  
2014 ◽  
Vol 8 (3) ◽  
pp. 2345-2359 ◽  
Author(s):  
Qingxiang Song ◽  
Meng Huang ◽  
Lei Yao ◽  
Xiaolin Wang ◽  
Xiao Gu ◽  
...  
2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Li Zuo ◽  
Benjamin T. Hemmelgarn ◽  
Chia-Chen Chuang ◽  
Thomas M. Best

An increasing number of studies have proposed a strong correlation between reactive oxygen species (ROS)-induced oxidative stress (OS) and the pathogenesis of Alzheimer’s disease (AD). With over five million people diagnosed in the United States alone, AD is the most common type of dementia worldwide. AD includes progressive neurodegeneration, followed by memory loss and reduced cognitive ability. Characterized by the formation of amyloid-beta (Aβ) plaques as a hallmark, the connection between ROS and AD is compelling. Analyzing the ROS response of essential proteins in the amyloidogenic pathway, such as amyloid-beta precursor protein (APP) and beta-secretase (BACE1), along with influential signaling programs of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and c-Jun N-terminal kinase (JNK), has helped visualize the path between OS and Aβoverproduction. In this review, attention will be paid to significant advances in the area of OS, epigenetics, and their influence on Aβplaque assembly. Additionally, we aim to discuss available treatment options for AD that include antioxidant supplements, Asian traditional medicines, metal-protein-attenuating compounds, and histone modifying inhibitors.


2018 ◽  
Author(s):  
James P Higham ◽  
Bilal R Malik ◽  
Edgar Buhl ◽  
Jenny Dawson ◽  
Anna S Ogier ◽  
...  

ABSTRACTAlzheimer’s disease (AD) is the most common form of dementia and is characterized by the accumulation of extracellular amyloid beta (Aβ) plaques and intracellular neurofibrillary tangles of hyperphosphorylated Tau, including the 4R0N isoform. Recent epigenome-wide association studies (EWAS) of AD have identified a number of loci that are differentially methylated in AD cortex. Indeed, hypermethylation of the Ankyrin 1 (ANK1) gene in AD has been reported in the cortex in numerous different post-mortem brain cohorts. Little is known about the normal function of ANK1 in the healthy brain, nor the role it may play in AD. We have generated Drosophila models to allow us to functionally characterize Drosophila Ank2, the ortholog of human ANK1. These models have targeted reduction in the expression of Ank2 in neurons. We find that Drosophila with reduced neuronal Ank2 expression have shortened lifespan, reduced locomotion, reduced memory and reduced neuronal excitability similar to flies overexpressing either human mutant APP (that leads to Aβ42 production) and MAPT (that leads to 0N4R Tau). Therefore, we show that the mis-expression of Ank2 can drive disease relevant processes and phenocopy some features of AD and we propose targeting ANK1 may have therapeutic potential. This represents the first study to characterize a gene implicated in AD, which was nominated from EWAS.Author summaryThe majority (>95%) of Alzheimer’s disease (AD) cases are sporadic, with their incidence attributed to common genetic mutations, epigenetic variation, aging and the environment. There is no cure for AD and only limited treatment options which only treat the symptoms of AD and only work in some people. Recent epigenome-wide association studies (EWAS) in AD have highlighted hypermethylation of the Ankyrin1 (ANK1) gene in AD cortex. Little is known of the normal role of the gene in the brain. Here, we have demonstrated that Drosophila with reduced neuronal expression of the Drosophila ortholog of human ANK1 (Ank2), can drive AD relevant processes including locomotor difficulties, memory loss and shortened lifespan similar to expression of human amyloid-Beta or tau mutant proteins. Furthermore, increasing Ank2 expression reversed the memory loss caused by expression of human amyloid-Beta or tau mutant proteins, suggesting that targeting ANK1 may have therapeutic potential. This represents the first study to characterize a gene implicated in AD, which was nominated from EWAS.


2021 ◽  
Author(s):  
Niall Murphy

Alzheimer’s Disease is defined as progressive memory loss coincident with accumulation of aggregated amyloid beta and phosphorylated tau. Identifying the relationship between these features has guided Alzheimer’s Disease research for decades, principally with the view that aggregated proteins drive a neurodegenerative process. Here I propose that amyloid beta and phospho-tau write-protect and tag neuroplastic changes as they form, protecting and insuring established neuroplasticity from corruption. In way of illustration, binding of oligomeric amyloid beta to the prion receptor is presented as an example possible mechanism. The write-protecting process is conjected to occur at least partially under the governance of isodendritic neuromodulators such as norepinephrine and acetylcholine. Coincident with aging, animals are exposed to accumulating amounts of memorable information. Compounded with recent increases in life expectancy and exposure to information-rich environments this causes aggregating proteins to reach unforeseen toxic levels as mnemonic circuits overload. As the brain cannot purposefully delete memories nor protect against overaccumulation of aggregating proteins, the result is catastrophic breakdown on cellular and network levels causing memory loss.


Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 488 ◽  
Author(s):  
P. Hemachandra Reddy ◽  
Darryll MA Oliver

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by memory loss and multiple cognitive impairments. Several decades of intense research have revealed that multiple cellular changes are implicated in the development and progression of AD, including mitochondrial damage, synaptic dysfunction, amyloid beta (Aβ) formation and accumulation, hyperphosphorylated tau (P-Tau) formation and accumulation, deregulated microRNAs, synaptic damage, and neuronal loss in patients with AD. Among these, mitochondrial dysfunction and synaptic damage are early events in the disease process. Recent research also revealed that Aβ and P-Tau-induced defective autophagy and mitophagy are prominent events in AD pathogenesis. Age-dependent increased levels of Aβ and P-Tau reduced levels of several autophagy and mitophagy proteins. In addition, abnormal interactions between (1) Aβ and mitochondrial fission protein Drp1; (2) P-Tau and Drp1; and (3) Aβ and PINK1/parkin lead to an inability to clear damaged mitochondria and other cellular debris from neurons. These events occur selectively in affected AD neurons. The purpose of our article is to highlight recent developments of a Aβ and P-Tau-induced defective autophagy and mitophagy in AD. This article also summarizes several aspects of mitochondrial dysfunction, including abnormal mitochondrial dynamics (increased fission and reduced fusion), defective mitochondrial biogenesis, reduced ATP, increased free radicals and lipid peroxidation, and decreased cytochrome c oxidase (COX) activity and calcium dyshomeostasis in AD pathogenesis. Our article also discusses how reduced levels of Drp1, Aβ, and P-Tau can enhance the clearance of damaged mitochondria and other cellular debris by autophagy and mitophagy mechanisms.


2002 ◽  
Vol 38 ◽  
pp. 37-49 ◽  
Author(s):  
Janelle Nunan ◽  
David H Small

The proteolytic processing of the amyloid-beta protein precursor plays a key role in the development of Alzheimer's disease. Cleavage of the amyloid-beta protein precursor may occur via two pathways, both of which involve the action of proteases called secretases. One pathway, involving beta- and gamma-secretase, liberates amyloid-beta protein, a protein associated with the neurodegeneration seen in Alzheimer's disease. The alternative pathway, involving alpha-secretase, precludes amyloid-beta protein formation. In this review, we describe the progress that has been made in identifying the secretases and their potential as therapeutic targets in the treatment or prevention of Alzheimer's disease.


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