Non-uinform gut microbiota alteration patterns associated with therapeutic outcomes in an Alzheimer's disease animal model

2019 ◽  
Author(s):  
Min Wang ◽  
William Kwame Amakye ◽  
Jianing Cao ◽  
Congcong Gong ◽  
Xiaoyu Sun ◽  
...  

Abstract Background: Dysbiosis of gut microbiota is associated with the progression of beta-amyloid (Aβ) pathology in Alzheimer’s disease (AD). We aimed to identify uniform Aβ-responsible gut microbiota status as possible guideline for gut microbiota manipulation and the prediction of outcomes of microbiota targeted treatments. Six months old APP/PS1 mice from the same genetic background, housing and feeding conditions were then daily gavage with Metformin, peptides WN5 or PW5 to manipulate the gut microbiota for 12 weeks. Aβ pathology and gut microbiota were then explored and compared. Results: Fecal microbiota transplantation (FMT) from a 16 month old APP/PS1 mouse reconstituted the gut microbiota towards the donor and increased Aβ pathology in APP/PS1 mouse model. Metformin, peptides WN5 and PW5 all attenuated Aβ-plaque formation in APP/PS1 mouse model but each was associated with distinct gut microbiota status. No uniform gut microbiota pattern associated with Aβ pathology was found among different gut microbiota-targeted treatments. Conclusion: We found no uniform gut microbiota status associated with Aβ pathology suggesting gut microbiota status is not a suitable biomarker for AD diagnosis and treatment predictions. Alteration of gut microbiota in itself may not be sufficiently directly related to functional outcomes and might only be a shadow of deeper molecular mechanisms not fully understood. The findings here strongly suggested that the significance of gut microbiota alteration in disease pathology and treatment may have so far been over claimed and that interpretation of gut microbiota data should be done with utmost caution.

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.


2020 ◽  
Vol 10 (11) ◽  
pp. 814
Author(s):  
Emily M. Borsom ◽  
Keehoon Lee ◽  
Emily K. Cope

The human microbiota is composed of trillions of microbial cells inhabiting the oral cavity, skin, gastrointestinal (GI) tract, airways, and reproductive organs. The gut microbiota is composed of dynamic communities of microorganisms that communicate bidirectionally with the brain via cytokines, neurotransmitters, hormones, and secondary metabolites, known as the gut microbiota–brain axis. The gut microbiota–brain axis is suspected to be involved in the development of neurological diseases, including Alzheimer’s disease (AD), Parkinson’s disease, and Autism Spectrum Disorder. AD is an irreversible, neurodegenerative disease of the central nervous system (CNS), characterized by amyloid-β plaques, neurofibrillary tangles, and neuroinflammation. Microglia and astrocytes, the resident immune cells of the CNS, play an integral role in AD development, as neuroinflammation is a driving factor of disease severity. The gut microbiota–brain axis is a novel target for Alzheimer’s disease therapeutics to modulate critical neuroimmune and metabolic pathways. Potential therapeutics include probiotics, prebiotics, fecal microbiota transplantation, and dietary intervention. This review summarizes our current understanding of the role of the gut microbiota–brain axis and neuroinflammation in the onset and development of Alzheimer’s disease, limitations of current research, and potential for gut microbiota–brain axis targeted therapies.


2021 ◽  
Author(s):  
Sirena Soriano ◽  
Kristen Curry ◽  
Qi Wang ◽  
Elsbeth Chow ◽  
Todd Treangen ◽  
...  

Traumatic brain injury (TBI) cause neuroinflammation, exaggerated immune response, and, consequently, neurodegeneration. The gut microbiome is an essential modulator of the immune system, impacting in the brain. There are not effective treatments for TBI, therefore, modulating the gut microbiome may shed novel therapeutics for the damaged brain. Also, in patients with Alzheimer's disease (AD), the microbiota has been associated with a lack of diversity, which negatively modulates the immune system. This study aimed to determine whether the gut microbiota from AD mice exacerbates neurological deficits after TBI in young mice. For this purpose, we performed fecal microbiota transplants from AD (FMT-AD) mice into young C57BL/6 (wild-type, WT) mice following TBI. Thus, FMT-AD and fecal microbiota transplants from healthy controls (FMT-young) were administered orally to young WT mice after the TBI occurred. We first determined the gut microbiota diversity and composition by analyzing full-length 16S rRNA sequences from mouse fecal samples using the Oxford Nanopore MinION technology. We collected the blood, brain, and gut tissues for protein and immunohistochemical analysis. Our results showed that FMT-AD treatment stimulates a higher relative abundance of Muribaculum intestinal and a decrease in Lactobacillus johnsonii compared FMT-young treatment in WT mice. Furthermore, WT mice exhibited larger lesion volumes, increased the number of activated microglia/macrophages cells, and reduced motor recovery after FMT-AD compared to FMT-young one day after TBI. Thus, the gut microbiota from AD mice not only aggravates the neuroinflammatory response and motor recovery, but also increases the lesion size after TBI in young WT mice.


Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 779
Author(s):  
Pradeep K. Shukla ◽  
David F. Delotterie ◽  
Jianfeng Xiao ◽  
Joseph F. Pierre ◽  
RadhaKrishna Rao ◽  
...  

Alzheimer’s disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive decline, is a major cause of death and disability among the older population. Despite decades of scientific research, the underlying etiological triggers are unknown. Recent studies suggested that gut microbiota can influence AD progression; however, potential mechanisms linking the gut microbiota with AD pathogenesis remain obscure. In the present study, we provided a potential mechanistic link between dysbiotic gut microbiota and neuroinflammation associated with AD progression. Using a mouse model of AD, we discovered that unfavorable gut microbiota are correlated with abnormally elevated expression of gut NLRP3 and lead to peripheral inflammasome activation, which in turn exacerbates AD-associated neuroinflammation. To this end, we observe significantly altered gut microbiota compositions in young and old 5xFAD mice compared to age-matched non-transgenic mice. Moreover, 5xFAD mice demonstrated compromised gut barrier function as evident from the loss of tight junction and adherens junction proteins compared to non-transgenic mice. Concurrently, we observed increased expression of NLRP3 inflammasome and IL-1β production in the 5xFAD gut. Consistent with our hypothesis, increased gut–microbial–inflammasome activation is positively correlated with enhanced astrogliosis and microglial activation, along with higher expression of NLRP3 inflammasome and IL-1β production in the brains of 5xFAD mice. These data indicate that the elevated expression of gut–microbial–inflammasome components may be an important trigger for subsequent downstream activation of inflammatory and potentially cytotoxic mediators, and gastrointestinal NLRP3 may promote NLRP3 inflammasome-mediated neuroinflammation. Thus, modulation of the gut microbiota may be a potential strategy for the treatment of AD-related neurological disorders in genetically susceptible hosts.


2018 ◽  
Vol 2 (2) ◽  
pp. 241-258 ◽  
Author(s):  
Shelli R. Kesler ◽  
Paul Acton ◽  
Vikram Rao ◽  
William J. Ray

Neurodegeneration in Alzheimer’s disease (AD) is associated with amyloid-beta peptide accumulation into insoluble amyloid plaques. The five-familial AD (5XFAD) transgenic mouse model exhibits accelerated amyloid-beta deposition, neuronal dysfunction, and cognitive impairment. We aimed to determine whether connectome properties of these mice parallel those observed in patients with AD. We obtained diffusion tensor imaging and resting-state functional magnetic resonance imaging data for four transgenic and four nontransgenic male mice. We constructed both structural and functional connectomes and measured their topological properties by applying graph theoretical analysis. We compared connectome properties between groups using both binarized and weighted networks. Transgenic mice showed higher characteristic path length in weighted structural connectomes and functional connectomes at minimum density. Normalized clustering and modularity were lower in transgenic mice across the upper densities of the structural connectome. Transgenic mice also showed lower small-worldness index in higher structural connectome densities and in weighted structural networks. Hyper-correlation of structural and functional connectivity was observed in transgenic mice compared with nontransgenic controls. These preliminary findings suggest that 5XFAD mouse connectomes may provide useful models for investigating the molecular mechanisms of AD pathogenesis and testing the effectiveness of potential treatments.


2017 ◽  
Vol 59 (4) ◽  
pp. 1415-1426 ◽  
Author(s):  
Michail B. Evgen’ev ◽  
George S. Krasnov ◽  
Inna V. Nesterova ◽  
David G. Garbuz ◽  
Vadim L. Karpov ◽  
...  

2016 ◽  
Vol 2 (2) ◽  
pp. e1501244 ◽  
Author(s):  
Johnny Habchi ◽  
Paolo Arosio ◽  
Michele Perni ◽  
Ana Rita Costa ◽  
Maho Yagi-Utsumi ◽  
...  

The conversion of the β-amyloid (Aβ) peptide into pathogenic aggregates is linked to the onset and progression of Alzheimer’s disease. Although this observation has prompted an extensive search for therapeutic agents to modulate the concentration of Aβ or inhibit its aggregation, all clinical trials with these objectives have so far failed, at least in part because of a lack of understanding of the molecular mechanisms underlying the process of aggregation and its inhibition. To address this problem, we describe a chemical kinetics approach for rational drug discovery, in which the effects of small molecules on the rates of specific microscopic steps in the self-assembly of Aβ42, the most aggregation-prone variant of Aβ, are analyzed quantitatively. By applying this approach, we report that bexarotene, an anticancer drug approved by the U.S. Food and Drug Administration, selectively targets the primary nucleation step in Aβ42 aggregation, delays the formation of toxic species in neuroblastoma cells, and completely suppresses Aβ42 deposition and its consequences in a Caenorhabditis elegans model of Aβ42-mediated toxicity. These results suggest that the prevention of the primary nucleation of Aβ42 by compounds such as bexarotene could potentially reduce the risk of onset of Alzheimer’s disease and, more generally, that our strategy provides a general framework for the rational identification of a range of candidate drugs directed against neurodegenerative disorders.


2016 ◽  
Vol 310 (6) ◽  
pp. E388-E393 ◽  
Author(s):  
Jackob Moskovitz ◽  
Fang Du ◽  
Connor F. Bowman ◽  
Shirley S. Yan

Accumulation of oxidized proteins, and especially β-amyloid (Aβ), is thought to be one of the common causes of Alzheimer's disease (AD). The current studies determine the effect of an in vivo methionine sulfoxidation of Aβ through ablation of the methionine sulfoxide reductase A (MsrA) in a mouse model of AD, a mouse that overexpresses amyloid precursor protein (APP) and Aβ in neurons. Lack of MsrA fosters the formation of methionine sulfoxide in proteins, and thus its ablation in the AD-mouse model will increase the formation of methionine sulfoxide in Aβ. Indeed, the novel MsrA-deficient APP mice ( APP+/ MsrAKO) exhibited higher levels of soluble Aβ in brain compared with APP+ mice. Furthermore, mitochondrial respiration and the activity of cytochrome c oxidase were compromised in the APP+/ MsrAKO compared with control mice. These results suggest that lower MsrA activity modifies Aβ solubility properties and causes mitochondrial dysfunction, and augmenting its activity may be beneficial in delaying AD progression.


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