Upstream regulators and downstream effectors of NF-κB in Alzheimer's disease

Interaction of Wip1 and NF-κB regulates neuroinflammatory response in astrocytes

OBJECTIVE

The aims of the present study were to detect the interaction of Wip1 and NF-κB P65 in retina of an LPS-induced astrocytes activation model.

METHODS

The interaction between Wip1 and nuclear factor kappa B (NF-κB) P65 was observed in lipopolysaccharide (LPS)-stimulated primary rat astrocytes derived from retina. The expressions of Wip1 and NF-κB P65 were evaluated using Western blot and RT-PCR. Small interfering RNA (siRNA) against Wip1 was transfected into astrocytes to clarify the phosphorylation status and nuclear translocation of NF-κB P65 and expressions of these proinflammatory factors. Meanwhile, expression of Wip1 was assessed following treatment with NF-κB inhibitor.

RESULTS

Wip1 and phospho-NF-κB P65 (p-P65) expressions were significantly increased and colocalization in astrocytes after LPS treatment. The expression of p-P65 was augmented by transfected with Wip1 siRNA followed by LPS. Furthermore, pre-treatment with Wip1 siRNA further enhanced LPS-induced NF-κB P65 translocation into the nuclei and proinflammatory cytokine release. Finally, inhibition of NF-κB decreases Wip1 expression and transcription in primary astrocytes.

CONCLUSION

These data provide a mechanism for the role for a negative feedback loop of Wip1 and NF-κB in LPS-induced astrocytic activation.

Linking deregulation of non-coding RNA to the core pathophysiology of Alzheimer's disease: An integrative review

The human genome encodes a vast repertoire of protein non-coding RNAs (ncRNA), some specific to the brain. MicroRNAs, which interfere with the translation of target mRNAs, are of particular interest since their deregulation has been implicated in neurodegenerative disorders like Alzheimer's disease (AD). However, it remains challenging to link the complex body of observations on miRNAs and AD into a coherent framework. Using extensive graphical support, this article discusses how a diverse panoply of miRNAs convergently and divergently impact (and are impacted by) core pathophysiological processes underlying AD: neuroinflammation and oxidative stress; aberrant generation of β-amyloid-42 (Aβ42); anomalies in the production, cleavage and post-translational marking of Tau; impaired clearance of Aβ42 and Tau; perturbation of axonal organisation; disruption of synaptic plasticity; endoplasmic reticulum stress and the unfolded protein response; mitochondrial dysfunction; aberrant induction of cell cycle re-entry; and apoptotic loss of neurons. Intriguingly, some classes of miRNA provoke these cellular anomalies, whereas others act in a counter-regulatory, protective mode. Moreover, changes in levels of certain species of miRNA are a consequence of the above-mentioned anomalies. In addition to miRNAs, circular RNAs, piRNAs, long non-coding RNAs and other types of ncRNA are being increasingly implicated in AD. Overall, a complex mesh of deregulated and multi-tasking ncRNAs reciprocally interacts with core pathophysiological mechanisms underlying AD. Alterations in ncRNAs can be detected in CSF and the circulation as well as the brain and are showing promise as biomarkers, with the ultimate goal clinical exploitation as targets for novel modes of symptomatic and course-altering therapy.

Zfra restores memory deficits in Alzheimer's disease triple-transgenic mice by blocking aggregation of TRAPPC6AΔ, SH3GLB2, tau, and amyloid β, and inflammatory NF-κB activation

Introduction

Zinc finger-like protein that regulates apoptosis (Zfra) is a naturally occurring 31-amino-acid protein. Synthetic peptides Zfra1–31 and Zfra4–10 are known to effectively block the growth of many types of cancer cells.

Methods

Ten-month-old triple-transgenic (3×Tg) mice for Alzheimer's disease (AD) received synthetic Zfra peptides via tail vein injections, followed by examining restoration of memory deficits.

Results

Zfra significantly downregulated TRAPPC6AΔ, SH3GLB2, tau, and amyloid β (Αβ) aggregates in the brains of 3×Tg mice and effectively restored their memory capabilities. Zfra inhibited melanoma-induced neuronal death in the hippocampus and plaque formation in the cortex. Mechanistically, Zfra blocked the aggregation of amyloid β 42 and many serine-containing peptides in vitro, suppressed tumor necrosis factor–mediated NF-κB activation, and bound cytosolic proteins for accelerating their degradation in ubiquitin/proteasome-independent manner.

Discussion

Zfra peptides exhibit a strong efficacy in blocking tau aggregation and amyloid Αβ formation and restore memory deficits in 3×Tg mice, suggesting its potential for treatment of AD.

Nutrition and AGE-ing: Focusing on Alzheimer's Disease

Recently, the role of food and nutrition in preventing or delaying chronic disability in the elderly population has received great attention. Thanks to their ability to influence biochemical and biological processes, bioactive nutrients are considered modifiable factors capable of preserving a healthy brain status. A diet rich in vitamins and polyphenols and poor in saturated fatty acids has been recommended. In the prospective of a healthy diet, cooking methods should be also considered. In fact, cooking procedures can modify the original dietary content, contributing not only to the loss of healthy nutrients, but also to the formation of toxins, including advanced glycation end products (AGEs). These harmful compounds are adsorbed at intestinal levels and can contribute to the ageing process. The accumulation of AGEs in ageing (“AGE-ing”) is further involved in the exacerbation of neurodegenerative and many other chronic diseases. In this review, we discuss food's dual role as both source of bioactive nutrients and reservoir for potential toxic compounds—paying particular attention to the importance of proper nutrition in preventing/delaying Alzheimer's disease. In addition, we focus on the importance of a good education in processing food in order to benefit from the nutritional properties of an optimal diet.

Toxin-Induced Experimental Models of Learning and Memory Impairment

Animal models for learning and memory have significantly contributed to novel strategies for drug development and hence are an imperative part in the assessment of therapeutics. Learning and memory involve different stages including acquisition, consolidation, and retrieval and each stage can be characterized using specific toxin. Recent studies have postulated the molecular basis of these processes and have also demonstrated many signaling molecules that are involved in several stages of memory. Most insights into learning and memory impairment and to develop a novel compound stems from the investigations performed in experimental models, especially those produced by neurotoxins models. Several toxins have been utilized based on their mechanism of action for learning and memory impairment such as scopolamine, streptozotocin, quinolinic acid, and domoic acid. Further, some toxins like 6-hydroxy dopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amyloid-β are known to cause specific learning and memory impairment which imitate the disease pathology of Parkinson's disease dementia and Alzheimer's disease dementia. Apart from these toxins, several other toxins come under a miscellaneous category like an environmental pollutant, snake venoms, botulinum, and lipopolysaccharide. This review will focus on the various classes of neurotoxin models for learning and memory impairment with their specific mechanism of action that could assist the process of drug discovery and development for dementia and cognitive disorders.