scholarly journals The Eminent Role of microRNAs in the Pathogenesis of Alzheimer's Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Mohammad Samadian ◽  
Mahdi Gholipour ◽  
Mohammadreza Hajiesmaeili ◽  
Mohammad Taheri ◽  
Soudeh Ghafouri-Fard

Alzheimer's disease (AD) is an irrevocable neurodegenerative condition characterized by the presence of senile plaques comprising amassed β-amyloid peptides (Aβ) and neurofibrillary tangles mainly comprising extremely phosphorylated Tau proteins. Recent studies have emphasized the role of microRNAs (miRNAs) in the development of AD. A number of miRNAs, namely, miR-200a-3p, miR-195, miR-338-5p, miR-34a-5p, miR-125b-5p, miR-132, miR-384, miR-339-5p, miR-135b, miR-425-5p, and miR-339-5p, have been shown to participate in the development of AD through interacting with BACE1. Other miRNAs might affect the inflammatory responses in the course of AD. Aberrant expression of several miRNAs in the plasma samples of AD subjects has been shown to have the aptitude for differentiation of AD subjects from healthy subjects. Finally, a number of AD-modifying agents affect miRNA profile in cell cultures or animal models. We have performed a comprehensive search and summarized the obtained data about the function of miRNAs in AD in the current review article.

Epigenomics ◽  
2020 ◽  
Vol 12 (17) ◽  
pp. 1501-1513 ◽  
Author(s):  
Bo-Wen Wu ◽  
Jin-Dong Guo ◽  
Mi-Shan Wu ◽  
Yu Liu ◽  
Meng Lu ◽  
...  

Aim: Alzheimer’s disease (AD) is the most frequent cause of dementia and characterized by the accumulation of β-amyloid peptides in plaques and vessel walls. This study proposed a hypothesis of an inhibitory role of miR-96-5p in AD via regulating Foxo1. Methods & methods: AD mouse models were established by injecting with 1% pentobarbital. Results: Knockdown of miR-96-5p in the presence of naringin was shown to reduce the expression of Foxo1 and contents of superoxide dismutase, catalase and glutathione peroxidase, yet increase lipocalin-2 expression as well as hydroxyproline and malondialdehyde contents. Also, Foxo1-mediated lipocalin-2 inhibition attenuated AD. Conclusion: Our study shows downregulating miR-96-5p limited AD progression, highlighting miR-96-5p a potential therapeutic target in treating AD.


2020 ◽  
Vol 20 (9) ◽  
pp. 770-781 ◽  
Author(s):  
Poornima Sharma ◽  
Anjali Sharma ◽  
Faizana Fayaz ◽  
Sharad Wakode ◽  
Faheem H. Pottoo

Alzheimer’s disease (AD) is the most prevalent and severe neurodegenerative disease affecting more than 0.024 billion people globally, more common in women as compared to men. Senile plaques and amyloid deposition are among the main causes of AD. Amyloid deposition is considered as a central event which induces the link between the production of β amyloid and vascular changes. Presence of numerous biomarkers such as cerebral amyloid angiopathy, microvascular changes, senile plaques, changes in white matter, granulovascular degeneration specifies the manifestation of AD while an aggregation of tau protein is considered as a primary marker of AD. Likewise, microvascular changes, activation of microglia (immune defense system of CNS), amyloid-beta aggregation, senile plaque and many more biomarkers are nearly found in all Alzheimer’s patients. It was seen that 70% of Alzheimer’s cases occur due to genetic factors. It has been reported in various studies that apolipoprotein E(APOE) mainly APOE4 is one of the major risk factors for the later onset of AD. Several pathological changes also occur in the white matter which include dilation of the perivascular space, loss of axons, reactive astrocytosis, oligodendrocytes and failure to drain interstitial fluid. In this review, we aim to highlight the various biological signatures associated with the AD which may further help in discovering multitargeting drug therapy.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 690
Author(s):  
Umair Shabbir ◽  
Muhammad Sajid Arshad ◽  
Aysha Sameen ◽  
Deog-Hwan Oh

The gut microbiota (GM) represents a diverse and dynamic population of microorganisms and about 100 trillion symbiotic microbial cells that dwell in the gastrointestinal tract. Studies suggest that the GM can influence the health of the host, and several factors can modify the GM composition, such as diet, drug intake, lifestyle, and geographical locations. Gut dysbiosis can affect brain immune homeostasis through the microbiota–gut–brain axis and can play a key role in the pathogenesis of neurodegenerative diseases, including dementia and Alzheimer’s disease (AD). The relationship between gut dysbiosis and AD is still elusive, but emerging evidence suggests that it can enhance the secretion of lipopolysaccharides and amyloids that may disturb intestinal permeability and the blood–brain barrier. In addition, it can promote the hallmarks of AD, such as oxidative stress, neuroinflammation, amyloid-beta formation, insulin resistance, and ultimately the causation of neural death. Poor dietary habits and aging, along with inflammatory responses due to dysbiosis, may contribute to the pathogenesis of AD. Thus, GM modulation through diet, probiotics, or fecal microbiota transplantation could represent potential therapeutics in AD. In this review, we discuss the role of GM dysbiosis in AD and potential therapeutic strategies to modulate GM in AD.


2021 ◽  
pp. 1-22
Author(s):  
Mariana Van Zeller ◽  
Diogo M. Dias ◽  
Ana M. Sebastião ◽  
Cláudia A. Valente

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease commonly diagnosed among the elderly population. AD is characterized by the loss of synaptic connections, neuronal death, and progressive cognitive impairment, attributed to the extracellular accumulation of senile plaques, composed by insoluble aggregates of amyloid-β (Aβ) peptides, and to the intraneuronal formation of neurofibrillary tangles shaped by hyperphosphorylated filaments of the microtubule-associated protein tau. However, evidence showed that chronic inflammatory responses, with long-lasting exacerbated release of proinflammatory cytokines by reactive glial cells, contribute to the pathophysiology of the disease. NLRP3 inflammasome (NLRP3), a cytosolic multiprotein complex sensor of a wide range of stimuli, was implicated in multiple neurological diseases, including AD. Herein, we review the most recent findings regarding the involvement of NLRP3 in the pathogenesis of AD. We address the mechanisms of NLRP3 priming and activation in glial cells by Aβ species and the potential role of neurofibrillary tangles and extracellular vesicles in disease progression. Neuronal death by NLRP3-mediated pyroptosis, driven by the interneuronal tau propagation, is also discussed. We present considerable evidence to claim that NLRP3 inhibition, is undoubtfully a potential therapeutic strategy for AD.


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.


2020 ◽  
Vol 21 (18) ◽  
pp. 6739
Author(s):  
Sharmeelavathi Krishnan ◽  
Yasaswi Shrestha ◽  
Dona P. W. Jayatunga ◽  
Sarah Rea ◽  
Ralph Martins ◽  
...  

Neurodegenerative diseases result in a range of conditions depending on the type of proteinopathy, genes affected or the location of the degeneration in the brain. Proteinopathies such as senile plaques and neurofibrillary tangles in the brain are prominent features of Alzheimer’s disease (AD). Autophagy is a highly regulated mechanism of eliminating dysfunctional organelles and proteins, and plays an important role in removing these pathogenic intracellular protein aggregates, not only in AD, but also in other neurodegenerative diseases. Activating autophagy is gaining interest as a potential therapeutic strategy for chronic diseases featuring protein aggregation and misfolding, including AD. Although autophagy activation is a promising intervention, over-activation of autophagy in neurodegenerative diseases that display impaired lysosomal clearance may accelerate pathology, suggesting that the success of any autophagy-based intervention is dependent on lysosomal clearance being functional. Additionally, the effects of autophagy activation may vary significantly depending on the physiological state of the cell, especially during proteotoxic stress and ageing. Growing evidence seems to favour a strategy of enhancing the efficacy of autophagy by preventing or reversing the impairments of the specific processes that are disrupted. Therefore, it is essential to understand the underlying causes of the autophagy defect in different neurodegenerative diseases to explore possible therapeutic approaches. This review will focus on the role of autophagy during stress and ageing, consequences that are linked to its activation and caveats in modulating this pathway as a treatment.


Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1267 ◽  
Author(s):  
Md. Sahab Uddin ◽  
Md. Tanvir Kabir ◽  
Kamal Niaz ◽  
Philippe Jeandet ◽  
Christophe Clément ◽  
...  

Alzheimer’s disease (AD) is one of the utmost chronic neurodegenerative disorders, which is characterized from a neuropathological point of view by the aggregates of amyloid beta (Aβ) peptides that are deposited as senile plaques and tau proteins which form neurofibrillary tangles (NFTs). Even though advancement has been observed in order to understand AD pathogenesis, currently available therapeutic methods can only deliver modest symptomatic relief. Interestingly, naturally occurring dietary flavonoids have gained substantial attention due to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties as alternative candidates for AD therapy. Experimental proof provides support to the idea that some flavonoids might protect AD by interfering with the production and aggregation of Aβ peptides and/or decreasing the aggregation of tau. Flavonoids have the ability to promote clearance of Aβ peptides and inhibit tau phosphorylation by the mTOR/autophagy signaling pathway. Moreover, due to their cholinesterase inhibitory potential, flavonoids can represent promising symptomatic anti-Alzheimer agents. Several processes have been suggested for the aptitude of flavonoids to slow down the advancement or to avert the onset of Alzheimer’s pathogenesis. To enhance cognitive performance and to prevent the onset and progress of AD, the interaction of flavonoids with various signaling pathways is proposed to exert their therapeutic potential. Therefore, this review elaborates on the probable therapeutic approaches of flavonoids aimed at averting or slowing the progression of the AD pathogenesis.


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