Neuroinflammation in Alzheimer’s disease: focus on NLRP1 and NLRP3 inflammasomes

Author(s):  
Eliana Cristina de Brito Toscano ◽  
Natalia Pessoa Rocha ◽  
Beatriz Noele Azevedo Lopes ◽  
Claudia Kimie Suemoto ◽  
Antonio Lucio Teixeira

Background: Alzheimer’s disease (AD) is the main cause of dementia worldwide. The definitive diagnosis of AD is clinicopathological and based on the identification of cerebral deposition of amyloid β (Aβ) plaques and neurofibrillary tangles. However, the link between amyloid cascade and depositions of phosphorylated tau (p-tau) is still missing. In this scenario, inflammasomes might play a relevant role. Experimental models of AD have suggested that Aβ accumulation induces, through microglia, activation of the NLRP3 inflammasome. This activation contributes to the dissemination of Aβ and p-tau, as well as to hyperphosphorylation of tau. Also in experimental models, NLPR1 promoted neuronal pyroptosis. There are neither comprehensive neuropathologic characterization, nor clinicopathologic studies evaluating the NLRP1 and NLRP3 inflammasomes in subjects with AD. Objective: The current mini-review aims to summarize recent and promising findings on the role of NLRP1 and NLRP3 signaling in the pathophysiology of AD. We also sought to highlight the knowledge gap in patients with AD, mainly the lack of clinicopathologic studies on the interaction among inflammasomes, Aβ/tau pathology, and cognitive decline.

2019 ◽  
Vol 68 (1) ◽  
pp. 415-415 ◽  
Author(s):  
Walter Gulisano ◽  
Daniele Maugeri ◽  
Marian A. Baltrons ◽  
Mauro Fà ◽  
Arianna Amato ◽  
...  

2018 ◽  
Vol 64 (s1) ◽  
pp. S611-S631 ◽  
Author(s):  
Walter Gulisano ◽  
Daniele Maugeri ◽  
Marian A. Baltrons ◽  
Mauro Fà ◽  
Arianna Amato ◽  
...  

2020 ◽  
Vol 19 (2) ◽  
pp. 85-93
Author(s):  
Win Ning Chen ◽  
Keng Yoon Yeong

Scopolamine as a drug is often used to treat motion sickness. Derivatives of scopolamine have also found applications as antispasmodic drugs among others. In neuroscience-related research, it is often used to induce cognitive disorders in experimental models as it readily permeates the bloodbrain barrier. In the context of Alzheimer’s disease, its effects include causing cholinergic dysfunction and increasing amyloid-β deposition, both of which are hallmarks of the disease. Hence, the application of scopolamine in Alzheimer’s disease research is proven pivotal but seldom discussed. In this review, the relationship between scopolamine and Alzheimer’s disease will be delineated through an overall effect of scopolamine administration and its specific mechanisms of action, discussing mainly its influences on cholinergic function and amyloid cascade. The validity of scopolamine as a model of cognitive impairment or neurotoxin model will also be discussed in terms of advantages and limitations with future insights.


2013 ◽  
Vol 66 (5) ◽  
pp. 362-366 ◽  
Author(s):  
Barnabas James Gilbert

The amyloid-β peptide (Aβ) is widely considered to be the major toxic agent in the pathogenesis of Alzheimer's disease, a condition which afflicts approximately 36 million people worldwide. Despite a plethora of studies stretching back over two decades, identifying the toxic Aβ species has proved difficult. Debate has centred on the Aβ fibril and oligomer. Despite support from numerous experimental models, important questions linger regarding the role of the Aβ oligomer in particular. It is likely a huge array of oligomers, rather than a single species, which cause toxicity. Reappraisal of the role of the Aβ fibril points towards a dynamic relationship with the Aβ oligomer within an integrated system, as supported by evidence from microglia. However, some continue to doubt the pathological role of amyloid β, instead proposing a protective role. If the field is to progress, all Aβ oligomers should be characterised, the nomenclature revised and a consistent experimental protocol defined. For this to occur, collaboration will be required between major research groups and innovative analytical tools developed. Such action must surely be taken if amyloid-based therapeutic endeavour is to progress.


Author(s):  
Roger G. Biringer

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders known. Estimates from the Alzheimer’s Association suggest that there are currently 5.8 million Americans living with the disease and that this will rise to 14 million by 2050. Research over the decades has revealed that AD pathology is complex and involves a number of cellular processes. In addition to the well-studied amyloid-β and tau pathology, oxidative damage to lipids and inflammation are also intimately involved. One aspect all these processes share is eicosanoid signaling. Eicosanoids are derived from polyunsaturated fatty acids by enzymatic or non-enzymatic means and serve as short-lived autocrine or paracrine agents. Some of these eicosanoids serve to exacerbate AD pathology while others serve to remediate AD pathology. A thorough understanding of eicosanoid signaling is paramount for understanding the underlying mechanisms and developing potential treatments for AD. In this review, eicosanoid metabolism is examined in terms of in vivo production, sites of production, receptor signaling, non-AD biological functions, and known participation in AD pathology.


2014 ◽  
Vol 56 ◽  
pp. 99-110 ◽  
Author(s):  
David Allsop ◽  
Jennifer Mayes

One of the hallmarks of AD (Alzheimer's disease) is the formation of senile plaques in the brain, which contain fibrils composed of Aβ (amyloid β-peptide). According to the ‘amyloid cascade’ hypothesis, the aggregation of Aβ initiates a sequence of events leading to the formation of neurofibrillary tangles, neurodegeneration, and on to the main symptom of dementia. However, emphasis has now shifted away from fibrillar forms of Aβ and towards smaller and more soluble ‘oligomers’ as the main culprit in AD. The present chapter commences with a brief introduction to the disease and its current treatment, and then focuses on the formation of Aβ from the APP (amyloid precursor protein), the genetics of early-onset AD, which has provided strong support for the amyloid cascade hypothesis, and then on the development of new drugs aimed at reducing the load of cerebral Aβ, which is still the main hope for providing a more effective treatment for AD in the future.


2020 ◽  
Vol 17 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Patrick Süß ◽  
Johannes C.M. Schlachetzki

: Alzheimer’s Disease (AD) is the most frequent neurodegenerative disorder. Although proteinaceous aggregates of extracellular Amyloid-β (Aβ) and intracellular hyperphosphorylated microtubule- associated tau have long been identified as characteristic neuropathological hallmarks of AD, a disease- modifying therapy against these targets has not been successful. An emerging concept is that microglia, the innate immune cells of the brain, are major players in AD pathogenesis. Microglia are longlived tissue-resident professional phagocytes that survey and rapidly respond to changes in their microenvironment. Subpopulations of microglia cluster around Aβ plaques and adopt a transcriptomic signature specifically linked to neurodegeneration. A plethora of molecules and pathways associated with microglia function and dysfunction has been identified as important players in mediating neurodegeneration. However, whether microglia exert either beneficial or detrimental effects in AD pathology may depend on the disease stage. : In this review, we summarize the current knowledge about the stage-dependent role of microglia in AD, including recent insights from genetic and gene expression profiling studies as well as novel imaging techniques focusing on microglia in human AD pathology and AD mouse models.


2021 ◽  
Vol 79 (3) ◽  
pp. 961-968
Author(s):  
Wolfgang J. Streit ◽  
Habibeh Khoshbouei ◽  
Ingo Bechmann

Microglia constitute the brain’s immune system and their involvement in Alzheimer’s disease has been discussed. Commonly, and in line with the amyloid/neuroinflammation cascade hypothesis, microglia have been portrayed as potentially dangerous immune effector cells thought to be overactivated by amyloid and producing neurotoxic inflammatory mediators that lead to neurofibrillary degeneration. We disagree with this theory and offer as an alternative the microglial dysfunction theory stating that microglia become impaired in their normally neuroprotective roles because of aging, i.e., they become senescent and aging neurons degenerate because they lack the needed microglial support for their survival. Thus, while the amyloid cascade theory relies primarily on genetic data, the dysfunction theory incorporates aging as a critical etiological factor. Aging is the greatest risk factor for the sporadic (late-onset) and most common form of Alzheimer’s disease, where fully penetrant genetic mutations are absent. In this review, we lay out and discuss the human evidence that supports senescent microglial dysfunction and conflicts with the amyloid/neuroinflammation idea.


2014 ◽  
Vol 42 (5) ◽  
pp. 1321-1325 ◽  
Author(s):  
Emma C. Phillips ◽  
Cara L. Croft ◽  
Ksenia Kurbatskaya ◽  
Michael J. O’Neill ◽  
Michael L. Hutton ◽  
...  

Increased production of amyloid β-peptide (Aβ) and altered processing of tau in Alzheimer's disease (AD) are associated with synaptic dysfunction, neuronal death and cognitive and behavioural deficits. Neuroinflammation is also a prominent feature of AD brain and considerable evidence indicates that inflammatory events play a significant role in modulating the progression of AD. The role of microglia in AD inflammation has long been acknowledged. Substantial evidence now demonstrates that astrocyte-mediated inflammatory responses also influence pathology development, synapse health and neurodegeneration in AD. Several anti-inflammatory therapies targeting astrocytes show significant benefit in models of disease, particularly with respect to tau-associated neurodegeneration. However, the effectiveness of these approaches is complex, since modulating inflammatory pathways often has opposing effects on the development of tau and amyloid pathology, and is dependent on the precise phenotype and activities of astrocytes in different cellular environments. An increased understanding of interactions between astrocytes and neurons under different conditions is required for the development of safe and effective astrocyte-based therapies for AD and related neurodegenerative diseases.


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