The Anti-diabetic Drug Gliquidone Modulates Lipopolysaccharide-Mediated Microglial Neuroinflammatory Responses by Inhibiting the NLRP3 Inflammasome

The sulfonylurea drug gliquidone is FDA approved for the treatment of type 2 diabetes. Binding of gliquidone to ATP-sensitive potassium channels (SUR1, Kir6 subunit) in pancreatic β-cells increases insulin release to regulate blood glucose levels. Diabetes has been associated with increased levels of neuroinflammation, and therefore the potential effects of gliquidone on micro- and astroglial neuroinflammatory responses in the brain are of interest. Here, we found that gliquidone suppressed LPS-mediated microgliosis, microglial hypertrophy, and proinflammatory cytokine COX-2 and IL-6 levels in wild-type mice, with smaller effects on astrogliosis. Importantly, gliquidone downregulated the LPS-induced microglial NLRP3 inflammasome and peripheral inflammation in wild-type mice. An investigation of the molecular mechanism of the effects of gliquidone on LPS-stimulated proinflammatory responses showed that in BV2 microglial cells, gliquidone significantly decreased LPS-induced proinflammatory cytokine levels and inhibited ERK/STAT3/NF-κB phosphorylation by altering NLRP3 inflammasome activation. In primary astrocytes, gliquidone selectively affected LPS-mediated proinflammatory cytokine expression and decreased STAT3/NF-κB signaling in an NLRP3-independent manner. These results indicate that gliquidone differentially modulates LPS-induced microglial and astroglial neuroinflammation in BV2 microglial cells, primary astrocytes, and a model of neuroinflammatory disease.

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Dasatinib regulates LPS-induced microglial and astrocytic neuroinflammatory responses by inhibiting AKT/STAT3 signaling

Journal of Neuroinflammation ◽

10.1186/s12974-019-1561-x ◽

2019 ◽

Vol 16 (1) ◽

Cited By ~ 10

Author(s):

Ka-Young Ryu ◽

Hyun-ju Lee ◽

Hanwoong Woo ◽

Ri-Jin Kang ◽

Kyung-Min Han ◽

...

Keyword(s):

Proinflammatory Cytokine ◽

Tween 80 ◽

Subcellular Fractionation ◽

Microglial Cells ◽

Wild Type ◽

Stat3 Signaling ◽

Tnf Α ◽

Cytokine Levels ◽

Primary Astrocytes ◽

Bv2 Microglial Cells

Abstract Background The FDA-approved small-molecule drug dasatinib is currently used as a treatment for chronic myeloid leukemia (CML). However, the effects of dasatinib on microglial and/or astrocytic neuroinflammatory responses and its mechanism of action have not been studied in detail. Methods BV2 microglial cells, primary astrocytes, or primary microglial cells were treated with dasatinib (100 or 250 nM) or vehicle (1% DMSO) for 30 min or 2 h followed by lipopolysaccharide (LPS; 200 ng/ml or 1 μg/ml) or PBS for 5.5 h. RT-PCR, real-time PCR; immunocytochemistry; subcellular fractionation; and immunohistochemistry were subsequently conducted to determine the effects of dasatinib on LPS-induced neuroinflammation. In addition, wild-type mice were injected with dasatinib (20 mg/kg, intraperitoneally (i.p.) daily for 4 days or 20 mg/kg, orally administered (p.o.) daily for 4 days or 2 weeks) or vehicle (4% DMSO + 30% polyethylene glycol (PEG) + 5% Tween 80), followed by injection with LPS (10 mg/kg, i.p.) or PBS. Then, immunohistochemistry was performed, and plasma IL-6, IL-1β, and TNF-α levels were analyzed by ELISA. Results Dasatinib regulates LPS-induced proinflammatory cytokine and anti-inflammatory cytokine levels in BV2 microglial cells, primary microglial cells, and primary astrocytes. In BV2 microglial cells, dasatinib regulates LPS-induced proinflammatory cytokine levels by regulating TLR4/AKT and/or TLR4/ERK signaling. In addition, intraperitoneal injection and oral administration of dasatinib suppress LPS-induced microglial/astrocyte activation, proinflammatory cytokine levels (including brain and plasma levels), and neutrophil rolling in the brains of wild-type mice. Conclusions Our results suggest that dasatinib modulates LPS-induced microglial and astrocytic activation, proinflammatory cytokine levels, and neutrophil rolling in the brain.

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Ephedrine ameliorates cerebral ischemia injury via inhibiting NOD-like receptor pyrin domain 3 inflammasome activation through the Akt/GSK3β/NRF2 pathway

Human & Experimental Toxicology ◽

10.1177/09603271211052981 ◽

2021 ◽

pp. 096032712110529

Author(s):

Qunxian Li ◽

Jing Wu ◽

Lixian Huang ◽

Bo Zhao ◽

Qingbin Li

Keyword(s):

Ischemic Stroke ◽

Nlrp3 Inflammasome ◽

Microglial Cells ◽

Inflammasome Activation ◽

Nrf2 Pathway ◽

Pyrin Domain ◽

Nlrp3 Inflammasome Activation ◽

Tnf Α ◽

Domain 3 ◽

Bv2 Microglial Cells

Ischemic stroke is a leading cause of death and long-term disability worldwide. The aim of this study is to explore the potential function of ephedrine in ischemic stroke and the underlying molecular mechanism. A middle cerebral artery occlusion (MCAO) rat model was established. The potential effects of ephedrine on MCAO rats and LPS-stimulated BV2 microglial cells were evaluated. Ephedrine reduced the infarct volume, cell apoptosis, brain water content, neurological score, and proinflammatory cytokines (TNF-α and IL-1β) production in MCAO rats. Ephedrine treatment also suppressed TNF-α and IL-1β production and NOD-like receptor pyrin domain 3 (NLRP3) inflammasome activation in BV2 microglial cells. The expression of NLRP3, caspase-1, and IL-1β was suppressed by ephedrine. Moreover, ephedrine treatment increased the phosphorylation of Akt and GSK3β and nuclear NRF2 levels in LPS-treated BV2 microglial cells. Meanwhile, LY294002 attenuated the inhibitory effects of ephedrine on NLRP3 inflammasome activation and TNF-α and IL-1β production. In addition, the level of pAkt was increased, while NLRP3, caspase-1, and IL-1β were decreased by ephedrine treatment in MCAO rats. In conclusion, ephedrine ameliorated cerebral ischemia injury via inhibiting NLRP3 inflammasome activation through the Akt/GSK3β/NRF2 pathway. Our results revealed a potential role of ephedrine in ischemic stroke treatment.

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The MAO Inhibitor Tranylcypromine Alters LPS- and Aβ-Mediated Neuroinflammatory Responses in Wild-type Mice and a Mouse Model of AD

Cells ◽

10.3390/cells9091982 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1982

Author(s):

HyunHee Park ◽

Kyung-Min Han ◽

Hyongjun Jeon ◽

Ji-Soo Lee ◽

Hyunju Lee ◽

...

Keyword(s):

Mouse Model ◽

Proinflammatory Cytokine ◽

Microglial Activation ◽

Microglial Cells ◽

Wild Type ◽

Mao Inhibitor ◽

Cytokine Levels ◽

Bv2 Microglial Cells

Monoamine oxidase (MAO) has been implicated in neuroinflammation, and therapies targeting MAO are of interest for neurodegenerative diseases. The small-molecule drug tranylcypromine, an inhibitor of MAO, is currently used as an antidepressant and in the treatment of cancer. However, whether tranylcypromine can regulate LPS- and/or Aβ-induced neuroinflammation in the brain has not been well-studied. In the present study, we found that tranylcypromine selectively altered LPS-induced proinflammatory cytokine levels in BV2 microglial cells but not primary astrocytes. In addition, tranylcypromine modulated LPS-mediated TLR4/ERK/STAT3 signaling to alter neuroinflammatory responses in BV2 microglial cells. Importantly, tranylcypromine significantly reduced microglial activation as well as proinflammatory cytokine levels in LPS-injected wild-type mice. Moreover, injection of tranylcypromine in 5xFAD mice (a mouse model of AD) significantly decreased microglial activation but had smaller effects on astrocyte activation. Taken together, our results suggest that tranylcypromine can suppress LPS- and Aβ-induced neuroinflammatory responses in vitro and in vivo.

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SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation

Nature Communications ◽

10.1038/s41467-021-25015-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Pan Pan ◽

Miaomiao Shen ◽

Zhenyang Yu ◽

Weiwei Ge ◽

Keli Chen ◽

...

Keyword(s):

Lung Injury ◽

Nlrp3 Inflammasome ◽

Cultured Cells ◽

Inflammatory Responses ◽

Specific Inhibitor ◽

Inflammasome Activation ◽

N Protein ◽

Distinct Mechanism ◽

Nlrp3 Inflammasome Activation ◽

Proinflammatory Responses

AbstractExcessive inflammatory responses induced upon SARS-CoV-2 infection are associated with severe symptoms of COVID-19. Inflammasomes activated in response to SARS-CoV-2 infection are also associated with COVID-19 severity. Here, we show a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation. N protein facilitates maturation of proinflammatory cytokines and induces proinflammatory responses in cultured cells and mice. Mechanistically, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates NLRP3 inflammasome assembly. More importantly, N protein aggravates lung injury, accelerates death in sepsis and acute inflammation mouse models, and promotes IL-1β and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production are blocked by MCC950 (a specific inhibitor of NLRP3) and Ac-YVAD-cmk (an inhibitor of caspase-1). Therefore, this study reveals a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses.

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Aggregated Tau-PHF6 (VQIVYK) Potentiates NLRP3 Inflammasome Expression and Autophagy in Human Microglial Cells

Cells ◽

10.3390/cells10071652 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1652

Author(s):

Chinmaya Panda ◽

Clara Voelz ◽

Pardes Habib ◽

Christian Mevissen ◽

Thomas Pufe ◽

...

Keyword(s):

Tau Protein ◽

Nlrp3 Inflammasome ◽

Time Dependent ◽

Microglial Cells ◽

Inflammasome Activation ◽

Dependent Manner ◽

Progressive Dementia ◽

Microglial Polarization ◽

Protein Levels ◽

Pyrin Domain

Intra-neuronal misfolding of monomeric tau protein to toxic β-sheet rich neurofibrillary tangles is a hallmark of Alzheimer’s disease (AD). Tau pathology correlates not only with progressive dementia but also with microglia-mediated inflammation in AD. Amyloid-beta (Aβ), another pathogenic peptide involved in AD, has been shown to activate NLRP3 inflammasome (NOD-like receptor family, pyrin domain containing 3), triggering the secretion of proinflammatory interleukin-1β (IL1β) and interleukin-18 (IL18). However, the effect of tau protein on microglia concerning inflammasome activation, microglial polarization, and autophagy is poorly understood. In this study, human microglial cells (HMC3) were stimulated with the unaggregated and aggregated forms of the tau-derived PHF6 peptide (VQIVYK). Modulation of NLRP3 inflammasome was examined by qRT-PCR, immunocytochemistry, and Western blot. We demonstrate that fibrillar aggregates of VQIVYK upregulated the NLRP3 expression at both mRNA and protein levels in a dose- and time-dependent manner, leading to increased expression of IL1β and IL18 in HMC3 cells. Aggregated PHF6-peptide also activated other related inflammation and microglial polarization markers. Furthermore, we also report a time-dependent effect of the aggregated PHF6 on BECN1 (Beclin-1) expression and autophagy. Overall, the PHF6 model system-based study may help to better understand the complex interconnections between Alzheimer’s PHF6 peptide aggregation and microglial inflammation, polarization, and autophagy.

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A Paradox in Bacterial Pathogenesis: Activation of the Local Macrophage Inflammasome Is Required for Virulence of Streptococcus uberis

Pathogens ◽

10.3390/pathogens9120997 ◽

2020 ◽

Vol 9 (12) ◽

pp. 997

Author(s):

Nathan Archer ◽

Sharon A. Egan ◽

Tracey J. Coffey ◽

Richard D. Emes ◽

M. Filippa Addis ◽

...

Keyword(s):

Mammary Epithelial Cells ◽

Ex Vivo ◽

Mammary Epithelial ◽

Inflammasome Activation ◽

Wild Type ◽

Independent Manner ◽

Streptococcus Uberis ◽

Correct Location ◽

Isogenic Mutants ◽

Transcriptomic Changes

Streptococcus uberis is a common cause of intramammary infection and mastitis in dairy cattle. Unlike other mammary pathogens, S. uberis evades detection by mammary epithelial cells, and the host–pathogen interactions during early colonisation are poorly understood. Intramammary challenge of dairy cows with S. uberis (strain 0140J) or isogenic mutants lacking the surface-anchored serine protease, SUB1154, demonstrated that virulence was dependent on the presence and correct location of this protein. Unlike the wild-type strain, the mutant lacking SUB1154 failed to elicit IL-1β from ex vivo CD14+ cells obtained from milk (bovine mammary macrophages, BMM), but this response was reinstated by complementation with recombinant SUB1154; the protein in isolation elicited no response. Production of IL-1β was ablated in the presence of various inhibitors, indicating dependency on internalisation and activation of NLRP3 and caspase-1, consistent with inflammasome activation. Similar transcriptomic changes were detected in ex vivo BMM in response to the wild-type or the SUB1154 deletion mutant, consistent with S. uberis priming BMM, enabling the SUB1154 protein to activate inflammasome maturation in a transcriptionally independent manner. These data can be reconciled in a novel model of pathogenesis in which, paradoxically, early colonisation is dependent on the innate response to the initial infection.

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Z-ligustilide protects BV-2 microglial cells against oxygen-glucose deprivation/reoxygenation-induced injury by inhibiting NLRP3 inflammasome activation and pyroptosis

European Journal of Inflammation ◽

10.1177/2058739220934925 ◽

2020 ◽

Vol 18 ◽

pp. 205873922093492

Author(s):

Jia Hu ◽

Jie Wei ◽

Cheng Zeng ◽

Fengqi Duan ◽

Sijun Liu ◽

...

Keyword(s):

Cell Viability ◽

Nlrp3 Inflammasome ◽

Glucose Deprivation ◽

Microglial Cells ◽

Cell Counting ◽

Oxygen Glucose Deprivation ◽

Inflammasome Activation ◽

Caspase 1 ◽

Nlrp3 Inflammasome Activation ◽

Active Caspase

Z-ligustilide (LIG) is the main bioactive compound of Danggui essential oil, which was reported to exert neuroprotective and anti-inflammatory effects. However, the underlying mechanism remains largely elusive. The present study aims to investigate the effect of LIG on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury and whether Nod-like receptor protein 3 (NLRP3) inflammasome and related pyroptosis are targets for the treatment of LIG. The OGD/R model was established in BV-2 microglial cells to investigate the protective effect of LIG. Cell viability and the release of lactate dehydrogenase (LDH) were determined by cell counting assay kit 8 and the LDH release assay kit. Western blot and immunofluorescence staining were carried out to detect NLRP3 inflammasome activation and pyroptosis. Active caspase-1 and TdT-mediated dUTP nick end labeling (TUNEL) double positive cells were defined as pyroptosis population. Statistical comparison among multiple groups was carried out by one-way analysis of variance (ANOVA) followed by least significant difference (LSD) test. Compared with control cells, OGD/R impaired cell viability and induced the release of LDH in BV-2 microglial cells, which were associated with the activation of NLRP3 inflammasome as evidenced by increased expression of NLRP3 and the cleavage of caspase-1 and interleukin-1 beta (IL-1β). In parallel with NLRP3 inflammasome activation, OGD/R induced pyroptotic cell death, manifested by the cleavage of gasdermin D (GSDMD) and increased population of active caspase-1+/TUNEL+ cells. All these events were significantly attenuated by treatment with LIG, indicating that LIG significantly inhibited NLRP3 inflammasome activation and pyroptosis, and ameliorated OGD/R-induced cell injury. In conclusion, LIG protects BV-2 microglial cells against OGD/R-induced injury via inhibition of NLRP3 inflammasome and pyroptosis.

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SARS-CoV-2 N promotes the NLRP3 inflammasome activation to induce hyperinflammation

10.21203/rs.3.rs-101224/v1 ◽

2020 ◽

Author(s):

Pan Pan ◽

Miaomiao Shen ◽

Zhenyang Yu ◽

Weiwei Ge ◽

Keli Chen ◽

...

Keyword(s):

Lung Injury ◽

Nlrp3 Inflammasome ◽

Cultured Cells ◽

Inflammatory Responses ◽

Pathological Process ◽

Inflammasome Activation ◽

N Protein ◽

Distinct Mechanism ◽

Nlrp3 Inflammasome Activation ◽

Proinflammatory Responses

Abstract Excessive inflammatory responses induced upon SARS-CoV-2 infection interlocks with severe symptoms and acute lung injury in patients with Severe Coronavirus Disease 2019 (COVID-19). Revealing the mechanism underlying the control of SARS-CoV-2-triggered immune-inflammatory responses would help us to understand the pathological process and guide clinical treatment. However, the effect of the NLRP3 inflammasome on regulating SARS-CoV-2-induced inflammatory responses has not been reported. Here, we revealed a distinct mechanism by which SARS-CoV-2 nucleocapsid (N) protein promotes the NLRP3 inflammasome activation to induce hyperinflammation. We demonstrated that N protein facilitates the maturation of proinflammatory cytokines IL-1β and IL-6 and induces proinflammatory responses in cultured cells and mice tissues. In team of molecular mechanism, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates the assemble of the inflammasome complex. More importantly, N protein aggravates lung injury, accelerated death in sepsis and acute inflammation mouse models, and promotes IL-1β and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production were blocked by Ac-YVAD-cmk, an inhibitor of the NLRP3 inflammasome. Therefore, this study revealed a distinct mechanism by which SARS-CoV-2 N protein promotes the NLRP3 inflammasome activation and induces excessive inflammatory responses.

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