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

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.

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Systemic inflammasome activation and pyroptosis associate with the progression of amnestic mild cognitive impairment and Alzheimer’s disease

Journal of Neuroinflammation ◽

10.1186/s12974-021-02329-2 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Wenjuan Rui ◽

Hong Xiao ◽

Yi Fan ◽

Zhongxuan Ma ◽

Ming Xiao ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Cognitive Assessment ◽

Mononuclear Cells ◽

Quantitative Polymerase Chain Reaction ◽

Amnestic Mild Cognitive Impairment ◽

Enzyme Linked Immunosorbent Assay ◽

Inflammasome Activation

Abstract Background Growing evidence indicates that inflammasome-mediated inflammation plays important roles in the pathophysiology of amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). Pyroptosis induced by inflammasome, and Gasdermin D (GSDMD) is involved in several neurodegenerative disorders. However, it is not clear whether peripheral inflammasome and pyroptosis are activated in aMCI and AD patients, influencing on neuroinflammation. The aim of this study was to examine the association between systemic inflammasome-induced pyroptosis and clinical features in aMCI and AD. Methods A total of 86 participants, including 33 subjects with aMCI, 33 subjects with AD, and 20 cognitively normal controls, in this study. The Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) scale were used for cognitive assessment. Levels of inflammasome-related genes/proteins in peripheral blood mononuclear cells (PBMCs) were determined using quantitative polymerase chain reaction and Western blotting. The levels of IL-1β, Aβ1-42, Aβ1-40, p-tau, and t-tau in cerebrospinal fluid (CSF), as well as the plasma IL-1β level, were measured by enzyme-linked immunosorbent assay. Finally, lipopolysaccharides (LPS) were used to investigate the effects of systemic inflammasome-induced pyroptosis in an AD mice model. Results Several genes involved in the inflammatory response were enriched in PBMCs of AD patients. The mRNA and protein levels of NLRP3, caspase-1, GSDMD, and IL-1β were increased in PBMCs of aMCI and AD patients. The IL-1β level in plasma and CSF of aMCI and AD patients was significantly higher than that in controls and negatively correlated with the CSF Aβ1-42 level, as well as MMSE and MoCA scores. Furthermore, there was a positive correlation between the IL-1β level in plasma and CSF of aMCI or AD patients. In vivo experiments showed that systemic inflammasome-induced pyroptosis aggravated neuroinflammation in 5 × FAD mice. Conclusions Our findings showed that canonical inflammasome signaling and GSDMD-induced pyroptosis were activated in PBMCs of aMCI and AD patients. In addition, the proinflammatory cytokine IL-1β was strongly associated with the pathophysiology of aMCI and AD. As such, targeting inflammasome-induced pyroptosis may be a new approach to inhibit neuroinflammation in aMCI and AD patients.

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

Pharmaceuticals ◽

10.3390/ph14111187 ◽

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.

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2109

Journal of Clinical and Translational Science ◽

10.1017/cts.2017.21 ◽

2017 ◽

Vol 1 (S1) ◽

pp. 1-1

Author(s):

Stephanie Davis ◽

Jeffrey Huang

Keyword(s):

Mononuclear Cells ◽

Age Of Onset ◽

Quantitative Polymerase Chain Reaction ◽

Study Groups ◽

Interleukin 4 ◽

Enzyme Linked Immunosorbent Assay ◽

Peripheral Blood Mononuclear ◽

Repair Capacity ◽

Relapsing Remitting ◽

Inflammatory Profile

OBJECTIVES/SPECIFIC AIMS: The overall objective of this proposal is to establish and modulate the inflammatory profile of individuals across the spectrum of multiple sclerosis (MS), with a focus on determining the potential of interleukin 4-induced protein 1 (IL4I1) as a possible marker of progression and modulator of inflammation in human blood samples. METHODS/STUDY POPULATION: The proposed experimental approach involves isolating plasma and peripheral blood mononuclear cells (PBMCs) from individuals across the spectrum of MS phenotypes, and analyzing these samples primarily by quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) methods. Specifically, study groups include: (1) actively relapsing-remitting MS (a-RRMS), (2) non-actively relapsing-remitting MS (n-RRMS), (3) non-active secondary-progressive MS (SPMS), (4) other autoimmune diseases (OAD), (5) healthy controls (HC). RESULTS/ANTICIPATED RESULTS: We expect that IL4I1 treatment increases regulatory cytokine (eg, IL10, TGFb) expression while decreasing Th1 and Th17-derived cytokines (IFNg, IL17), as well as increasing relative composition of regulatory cells (Th2, Treg, M2) as compared with Th1, Th17, M1 (aim 1). Preliminary data on healthy control cells support this prediction. Our central hypothesis is that IL4I1 level indicates the body’s ability to repair itself. As such, we anticipate that all MS groups are deficient in IL4I1, to varying degrees, such that HC>n-RRMS>a-RRMS>SPMS. HC have full repair capacity. RRMS>SPMS as remission indicates existent repair capacity, which is lost in SPMS. n-RRMS>a-RRMS since both, as RRMS, capable of repair response, but a-RRMS triggered this response more recently in response to more recent relapse. In all groups, we expect IL4I-treatment to mitigate inflammation (aim 2). Finally, we expect that H2O2 production by IL4I1 is a key player in IL4I1 function, and that H2O2 will preferentially induce oxidative stress to pro-inflammatory subsets of PBCMs (aim 3). DISCUSSION/SIGNIFICANCE OF IMPACT: MS is a chronic inflammatory neurodegenerative disease of the central nervous system that, with an average age of onset of 34, afflicts over 2.3 million individuals worldwide during many of the most productive years of their lives. The pathogenesis of MS, which involves autoimmune destruction of myelin, is poorly understood. Accurate biomarkers, which could predict disease progression, are yet to be identified and would provide valuable information to patients and their treating clinicians. Likewise, effective treatments are few and in high demand. IL4I1 is a promising candidate for both roles.

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

Journal of Alzheimer s Disease ◽

10.3233/jad-215402 ◽

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.

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

Journal of Alzheimer s Disease ◽

10.3233/jad-215285 ◽

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.

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