scholarly journals Pharmacological and Epigenetic Regulators of NLRP3 Inflammasome Activation in Alzheimer’s Disease

2021 ◽  
Vol 14 (11) ◽  
pp. 1187
Author(s):  
Francesca La Rosa ◽  
Roberta Mancuso ◽  
Simone Agostini ◽  
Federica Piancone ◽  
Ivana Marventano ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nlrp3 Inflammasome ◽  
Mononuclear Cells ◽  
Cytokine Production ◽  
Protein Translation ◽  
Inflammasome Activation ◽  
Peripheral Blood Mononuclear ◽  
Caspase 1 ◽  
Inflammatory Status

Activation of the NLRP3 inflammasome complex results in the production of IL-18, Caspase-1 and IL-1β. These cytokines have a beneficial role in promoting inflammation, but an excessive activation of the inflammasome and the consequent constitutive inflammatory status is a negative factor in human pathologies including Alzheimer’s Disease (AD). MicroRNAs (miR-NAs) target the 3′UTR region of NLRP3, preventing the activation of the inflammasome and inhibiting cytokine production. Because Stavudine (D4T), an antiretroviral drug, was recently shown to reduce inflammasome activation, we verified whether its effect is mediated by miR-7-5p, miR-22-3p, miR-30e-5p and miR-223-3p: miRNAs that bind the NLRP3-mRNA-UTR region and interfere with protein translation, reducing NLRP3 activation. Peripheral blood mononuclear cells (PBMCs) of twenty AD patients and ten sex-matched Healthy Controls (HC) were stimulated with Lipopolysaccharides (LPS)+Amyloid-beta (Aβ42) in the absence/presence of D4T. Expression of genes within the inflammasome complex and of miRNAs was evaluated by RT-PCR; cytokines and caspase-1 production was measured by ELISA. Results have shown that: NLRP3, ASC, IL-1β and IL-18 expression, as well as IL-18, IL-1β and caspase-1 production, were significantly augmented (p < 0.05) in LPS+Aβ42-stimulated PBMCs of AD patients compared to HC. D4T reduced the expression of inflammasome genes and cytokine production (p < 0.005). miR-7-5p and miR-223-3p expression was significantly increased in LPS+Aβ42-stimulated PBMCs of AD patients (p < 0.05), and it was reduced by D4T in AD alone. In conclusion: miR-223-3p and mir-7-5p expression is increased in AD, but this does not result in down-regulation of NLRP3 inflammasome expression and of IL-1β and IL-18 production. D4T increased miRNA expression in HC but had an opposite effect in AD, suggesting that miRNA regulatory mechanisms are altered in AD.

scholarly journals Bruton’s tyrosine kinase drives neuroinflammation and anxiogenic behavior in mouse models of stress

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Simantini Ghosh ◽  
Zaidan Mohammed ◽  
Itender Singh
Keyword(s):  
Mouse Models ◽  
Peripheral Blood Mononuclear Cells ◽  
Nlrp3 Inflammasome ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Specific Inhibitor ◽  
Inflammasome Activation ◽  
Peripheral Blood Mononuclear ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

Abstract Background Current therapies targeting several neurotransmitter systems are only able to partially mitigate the symptoms of stress- and trauma-related disorder. Stress and trauma-related disorders lead to a prominent inflammatory response in humans, and in pre-clinical models. However, mechanisms underlying the induction of neuroinflammatory response in PTSD and anxiety disorders are not clearly understood. The present study investigated the mechanism underlying the activation of proinflammatory NLRP3 inflammasome and IL1β in mouse models of stress. Methods We used two mouse models of stress, i.e., mice subjected to physical restraint stress with brief underwater submersion, and predator odor stress. Mice were injected with MCC950, a small molecule specific inhibitor of NLRP3 activation. To pharmacologically inhibit BTK, a specific inhibitor ibrutinib was used. To validate the observation from ibrutinib studies, a separate group of mice was injected with another BTK-specific inhibitor LFM-A13. Seven days after the induction of stress, mice were examined for anxious behavior using open field test (OFT), light–dark test (LDT), and elevated plus maze test (EPM). Following the behavior tests, hippocampus and amygdale were extracted and analyzed for various components of NLRP3–caspase 1–IL1β pathway. Plasma and peripheral blood mononuclear cells were also used to assess the induction of NLRP3–Caspase 1–IL-1β pathway in stressed mice. Results Using two different pre-clinical models of stress, we demonstrate heightened anxious behavior in female mice as compared to their male counterparts. Stressed animals exhibited upregulation of proinflammatory IL1β, IL-6, Caspase 1 activity and NLRP3 inflammasome activation in brain, which were significantly higher in female mice. Pharmacological inhibition of NLRP3 inflammasome activation led to anxiolysis as well as attenuated neuroinflammatory response. Further, we observed induction of activated Bruton’s tyrosine kinase (BTK), an upstream positive-regulator of NLRP3 inflammasome activation, in hippocampus and amygdala of stressed mice. Next, we conducted proof-of-concept pharmacological BTK inhibitor studies with ibrutinib and LFM-A13. In both sets of experiments, we found BTK inhibition led to anxiolysis and attenuated neuroinflammation, as indicated by significant reduction of NLRP3 inflammasome and proinflammatory IL-1β in hippocampus and amygdala. Analysis of plasma and peripheral blood mononuclear cells indicated peripheral induction of NLRP3–caspase 1–IL1β pathway in stressed mice. Conclusion Our study identified BTK as a key upstream regulator of neuroinflammation, which drives anxiogenic behavior in mouse model of stress. Further, we demonstrated the sexually divergent activation of BTK, providing a clue to heightened neuroinflammation and anxiogenic response to stress in females as compared to their male counterparts. Our data from the pharmacological inhibition studies suggest BTK as a novel target for the development of potential clinical treatment of PTSD and anxiety disorders. Induction of pBTK and NLRP3 in peripheral blood mononuclear cells of stressed mice suggest the potential effect of stress on systemic inflammation.

scholarly journals Systemic Inflammasome Activation and Pyroptosis Associate with the Progression of Alzheimer’s Disease

2021 ◽  
Author(s):  
wenjuan rui ◽  
Hong Xiao ◽  
Yi Fan ◽  
Zhongxuan Ma ◽  
Ming Xiao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mononuclear Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Animal Experiments ◽  
Pathological Process ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammasome Activation ◽  
Mice Model ◽  
Peripheral Blood Mononuclear

Abstract Background: Growing evidence indicates that inflammasome-mediated inflammation plays an important role in the pathophysiology of Alzheimer’s disease (AD). Likewise, gasdermin D (GSDMD) as executive molecule in inflammasome-induced pyroptosis is also involved in many neurological disorders. However, it is not clear whether inflammasome and pyroptosis is activated in the periphery of AD patients and influences central inflammation. The aim of this study was to evaluate the association between systemic inflammasome-induced pyroptosis and clinical features in the progression of AD.Methods: A total of 86 participants, including 33 patients with AD, 33 patients with amnestic mild cognitive impairment (aMCI), and 20 controls, were included in this study. The cognitive level of each participant was evaluated, including Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores were assigned. We collected blood samples from each participant. Gene transcriptomes of peripheral blood mononuclear cells (PBMCs) were determined by RNA-seq. The expression levels of inflammasome-related genes/proteins in PBMCs were determined using quantitative polymerase chain reaction and western blotting. Cerebrospinal fluid (CSF) samples were collected from all AD patients. The levels of IL-1β, Aβ1-42, p-tau, and t-tau in CSF, as well as the plasma IL-1β level, were measured by enzyme-linked immunosorbent assay. Lastly, a low dose of lipopolysaccharides (LPS) was performed to investigate the effects of systemic pyroptosis in AD mice model.Results: Several genes involved in the inflammatory response pathway were enriched in PBMCs of AD patients. The mRNA and protein levels of NLRP3, caspase-1, GSDMD, and IL-1β were all increased in PBMCs from AD and aMCI patients. The IL-1β levels in plasma and CSF in AD and aMCI patients were significantly higher than those in controls and have a negative correlation with levels of Aβ1-42 in CSF, MMSE and MOCA scores. Furthermore, there was a positive correlation between the IL-1β level in plasma and CSF of AD or aMCI patients. In addition, animal experiments also showed that systemic pyroptosis aggravates neuroinflammation in 5×FAD mice.Conclusions: All these findings showed that the canonical inflammasome pathway and GSDMD-induced pyroptosis is activated in PBMCs from AD and aMCI patients. Proinflammatory cytokine IL-1β in periphery is highly associated with the pathological process of AD. Targeting peripheral inflammasomes and pyroptosis may be a strategy to inhibit neuroinflammation in AD.

scholarly journals Alterations in the Gut-Microbial-Inflammasome-Brain Axis in a Mouse Model of Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 779
Author(s):  
Pradeep K. Shukla ◽  
David F. Delotterie ◽  
Jianfeng Xiao ◽  
Joseph F. Pierre ◽  
RadhaKrishna Rao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Gut Microbiota ◽  
Transgenic Mice ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Gut Barrier Function ◽  
Elevated Expression ◽  
5Xfad Mice

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.

scholarly journals Key Mechanisms and Potential Implications of Hericium erinaceus in NLRP3 Inflammasome Activation by Reactive Oxygen Species during Alzheimer’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1664
Author(s):  
Marika Cordaro ◽  
Angela Trovato Salinaro ◽  
Rosalba Siracusa ◽  
Ramona D’Amico ◽  
Daniela Impellizzeri ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nlrp3 Inflammasome ◽  
Neuronal Degeneration ◽  
Behavioral Changes ◽  
Antioxidant Systems ◽  
Inflammasome Activation ◽  
Protective Effects ◽  
Behavioral Alteration ◽  
Hericium Erinaceus

Alzheimer’s disease (AD) is the principal cause of dementia, and its incidence increases with age. Altered antioxidant systems and inflammation have an important role in the etiology of neurodegenerative disorders. In this study, we evaluated the effects of Hericium erinaceus, a nutritional mushroom with important antioxidant effects, in a rat model of AD. Animals were injected with 70 mg/Kg of AlCl3 daily for 6 weeks, and Hericium erinaceus was administered daily by gavage. Before the experiment’s end date, behavioral test training was performed. At the end of the study, behavioral changes were assessed, and the animals were euthanized. Brain tissues were harvested for further analysis. AlCl3 mainly accumulates in the hippocampus, the principal region of the brain involved in memory functions and learning. Hericium erinaceus administration reduced behavioral changes and hippocampal neuronal degeneration. Additionally, it reduced phosphorylated Tau levels, aberrant APP overexpression, and β-amyloid accumulation. Moreover, Hericium erinaceus decreased the pro-oxidative and pro-inflammatory hippocampal alterations induced by AD. In particular, it reduced the activation of the NLRP3 inflammasome components, usually activated by increased oxidative stress during AD. Collectively, our results showed that Hericium erinaceus has protective effects on behavioral alteration and histological modification associated with AD due to the modulation of the oxidative and inflammatory pathways, as well as regulating cellular brain stress.

scholarly journals Diagnosing Alzheimer’s Disease from Circulating Blood Leukocytes Using a Fluorescent Amyloid Probe

2021 ◽  
pp. 1-14
Author(s):  
Stefanie A.G. Black ◽  
Anastasiia A. Stepanchuk ◽  
George W. Templeton ◽  
Yda Hernandez ◽  
Tomoko Ota ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Protein Misfolding ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Amyloid Β ◽  
Csf Biomarkers ◽  
Blood Leukocytes ◽  
Peripheral Blood Mononuclear ◽  
The Brain

Background: Toxic amyloid-β (Aβ) peptides aggregate into higher molecular weight assemblies and accumulate not only in the extracellular space, but also in the walls of blood vessels in the brain, increasing their permeability, and promoting immune cell migration and activation. Given the prominent role of the immune system, phagocytic blood cells may contact pathological brain materials. Objective: To develop a novel method for early Alzheimer’s disease (AD) detection, we used blood leukocytes, that could act as “sentinels” after trafficking through the brain microvasculature, to detect pathological amyloid by labelling with a conformationally-sensitive fluorescent amyloid probe and imaging with confocal spectral microscopy. Methods: Formalin-fixed peripheral blood mononuclear cells (PBMCs) from cognitively healthy control (HC) subjects, mild cognitive impairment (MCI) and AD patients were stained with the fluorescent amyloid probe K114, and imaged. Results were validated against cerebrospinal fluid (CSF) biomarkers and clinical diagnosis. Results: K114-labeled leukocytes exhibited distinctive fluorescent spectral signatures in MCI/AD subjects. Comparing subjects with single CSF biomarker-positive AD/MCI to negative controls, our technique yielded modest AUCs, which improved to the 0.90 range when only MCI subjects were included in order to measure performance in an early disease state. Combining CSF Aβ 42 and t-Tau metrics further improved the AUC to 0.93. Conclusion: Our method holds promise for sensitive detection of AD-related protein misfolding in circulating leukocytes, particularly in the early stages of disease.

Muscarinic Receptors Expression in the Peripheral Blood Cells Differentiate Dementia with Lewy Bodies from Alzheimer’s Disease

2021 ◽  
pp. 1-8
Author(s):  
Marcella Reale ◽  
Claudia Carrarini ◽  
Mirella Russo ◽  
Fedele Dono ◽  
Laura Ferri ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Peripheral Blood ◽  
Dementia With Lewy Bodies ◽  
Mononuclear Cells ◽  
Lewy Bodies ◽  
Acetylcholinesterase Inhibitors ◽  
Operating Characteristics ◽  
Peripheral Blood Mononuclear

Background: Central nervous system disruption of cholinergic (ACh) signaling, which plays a major role in cognitive processes, is well documented in dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD). The expression of muscarinic ACh receptors type 1 and 4 (CHRM1 and CHRM4) has been reported to be altered in the brain of DLB patients. Objective: We aim to assess the peripheral gene expression of CHRM1 and 4 in DLB as a possible marker as compared to AD and healthy control (HC) subjects. Methods: Peripheral blood mononuclear cells were collected from 21 DLB, 13 AD, and 8 HC matched subjects. RT-PCR was performed to estimate gene expression of CHRM1 and CHRM4. Results: Peripheral CHRM1 expression was higher and CHRM4 was lower in DLB and AD compared to HC, whereas both CHRM1 and CHRM4 levels were higher in AD compared to DLB patients. Receiver operating characteristics curves, with logistic regression analysis, showed that combining peripheral CHRM1 and CHRM4 levels, DLB and AD subjects were classified with an accuracy of 76.0%. Conclusion: Alterations of peripheral CHRM1 and CHRM4 was found in both AD and DLB patients as compared to HC. CHRM1 and CHRM4 gene expression resulted to be lower in DLB patients compared to AD. In the future, peripheral CHRM expression could be studied as a possible marker of neurodegenerative conditions associated with cholinergic deficit and a possible marker of response to acetylcholinesterase inhibitors.

scholarly journals Systemic activation of NLRP3 inflammasome and plasma α-synuclein levels are correlated with motor severity and progression in Parkinson’s disease

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Zheng Fan ◽  
Yu-Ting Pan ◽  
Zhi-Yuan Zhang ◽  
Hui Yang ◽  
Shu-Yue Yu ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nlrp3 Inflammasome ◽  
Plasma Levels ◽  
Mononuclear Cells ◽  
Inflammasome Activation ◽  
Complete Evaluation ◽  
Positive Correlation ◽  
Caspase 1 ◽  
Updrs Part

Abstract Background Emerging evidence indicates that inflammasome-induced inflammation plays a crucial role in the pathogenesis of Parkinson’s disease (PD). Several proteins including α-synuclein trigger the activation of NLRP3 inflammasome. However, few studies examined whether inflammasomes are activated in the periphery of PD patients and their possible value in the diagnosis or tracking of the progress of PD. The aim of this study was to determine the association between inflammasome-induced inflammation and clinical features in PD. Methods There were a total of 67 participants, including 43 patients with PD and 24 controls, in the study. Participants received a complete evaluation of motor and non-motor symptoms, including Hoehn and Yahr (H-Y) staging scale. Blood samples were collected from all participants. The protein and mRNA expression levels of inflammasomes subtypes and components in peripheral blood mononuclear cells (PBMCs) were determined using western blotting and RT-qPCR. We applied Meso Scale Discovery (MSD) immunoassay to measure the plasma levels of IL-1β and α-synuclein. Results We observed increased gene expression of NLRP3, ASC, and caspase-1 in PBMCs, and increased protein levels of NLRP3, caspase-1, and IL-1β in PD patients. Plasma levels of IL-1β were significantly higher in patients with PD compared with controls and have a positive correlation with H-Y stage and UPDRS part III scores. Furthermore, plasma α-synuclein levels were also increased in PD patients and have a positive correlation with both UPDRS part III scores and plasma IL-1β levels. Conclusions Our data demonstrated that the NLRP3 inflammasome is activated in the PBMCs from PD patients. The related inflammatory cytokine IL-1β and total α-synuclein in plasma were increased in PD patients than controls, and both of them presented a positive correlation with motor severity in patients with PD. Furthermore, plasma α-synuclein levels have a positive correlation with IL-1β levels in PD patients. All these findings suggested that the NLRP3 inflammasome activation-related cytokine IL-1β and α-synuclein could serve as non-invasive biomarkers to monitor the severity and progression of PD in regard to motor function.

scholarly journals Toll-Like Receptor 2 and NLRP3 Cooperate To Recognize a Functional Bacterial Amyloid, Curli

2014 ◽  
Vol 83 (2) ◽  
pp. 693-701 ◽  
Author(s):  
Glenn J. Rapsinski ◽  
Meghan A. Wynosky-Dolfi ◽  
Gertrude O. Oppong ◽  
Sarah A. Tursi ◽  
R. Paul Wilson ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nlrp3 Inflammasome ◽  
Amyloid Β ◽  
Underlying Mechanism ◽  
Secondary Amyloidosis ◽  
Toll Like Receptor ◽  
Content Type ◽  
Caspase 1 ◽  
Toll Like Receptor 2

Amyloids are proteins with cross-β-sheet structure that contribute to pathology and inflammation in complex human diseases, including Alzheimer's disease, Parkinson's disease, type II diabetes, and secondary amyloidosis. Bacteria also produce amyloids as a component of their extracellular matrix during biofilm formation. Recently, several human amyloids were shown to activate the NLRP3 inflammasome, leading to the activation of caspase 1 and production of interleukin 1β (IL-1β). In this study, we investigated the activation of the NLRP3 inflammasome by bacterial amyloids using curli fibers, produced bySalmonella entericaserovar Typhimurium andEscherichia coli. Here, we show that curli fibers activate the NLRP3 inflammasome, leading to the production of IL-1β via caspase 1 activation. Investigation of the underlying mechanism revealed that activation of Toll-like receptor 2 (TLR2) by curli fibers is critical in the generation of IL-1β. Interestingly, activation of the NLRP3 inflammasome by curli fibers or by amyloid β of Alzheimer's disease does not cause cell death in macrophages. Overall, these data identify a cross talk between TLR2 and NLRP3 in response to the bacterial amyloid curli and generation of IL-1β as a product of this interaction.

Sign in / Sign up

Export Citation Format

Share Document