P. aeruginosa biofilm activates the NLRP3 inflammasomes in vitro

2022 ◽  
pp. 105379
Author(s):  
Qi Tan ◽  
Qing Ai ◽  
Yu He ◽  
Fang Li ◽  
Jialin Yu
Keyword(s):  
Nlrp3 Inflammasomes

Abstract P259: Endothelial Acid Sphingomyelinase Gene Determines Inflammasome Activation and Atherosclerotic Lesions in Carotid Arteries During Hypercholesterolemia

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Min Xia ◽  
Krishna M Bioni ◽  
Yang Chen ◽  
Xiang Li ◽  
Ashley L Pitzer ◽  
...  
Keyword(s):  
Carotid Arteries ◽  
Acid Sphingomyelinase ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Neointimal Formation ◽  
Atherosclerotic Lesions ◽  
Junction Protein ◽  
Nlrp3 Inflammasomes

Nucleotide oligomerization domain (NOD)-like receptor protein with pyrin domain containing 3 (Nlrp3) inflammasome has been reported to be activated by atherogenic factors, thereby triggering endothelial injury and consequent atherosclerotic lesions in the arterial wall. However, the mechanism activating and regulating Nlrp3 inflammasomes remains poorly understood. The present study tested whether membrane raft (MR) signaling platforms associated with acid sphingomyelinase (ASM) and its product ceramide (Ce) importantly contribute to the activation of Nlrp3 inflammasomes and atherosclerotic lesions during hypercholesterolemia (HC). By confocal microscopy and biochemical analyses, we demonstrated the formation and activation of Nlrp3 inflammasomes in the intima of the carotid arteries of Asm +/+ mice with HC (as shown by a 2-fold increase in caspase-1 activity and a 6-fold enhancement of IL-1β positive stain areas), but not in Asm -/- mice. In endothelium-specific ASM transgenic mice (EC-Asm trg ), this inflammasome formation and activation were enhanced. Correspondingly, HC-induced increases in IL-1β production, ASM expression, Ce level and MR-gp91 phox clustering in the carotid intima were abolished in Asm -/- mice, but enhanced in EC-Asm trg mice. Functionally, endothelium-dependent vasodilation (EDVD) in carotid arteries in vivo (by ultrasound flowmetry) and in vitro (in perfused artery) was impaired by HC in Asm +/+ mice by 33% and 54%, respectively. This endothelial dysfunction was not observed in Asm -/- mice. The endothelial tight junction protein, ZO-1 was reduced by HC in both Asm +/+ and EC-Asm trg mice, but not in Asm -/- mice. It was also found that HC-increased neointimal formation, T-cell infiltration, and fibrosis in 2-week partially ligated carotid arteries (PLCA) occurred in Asm +/+ mice, but not in Asm -/- mice with HC. EC-Asm trg mice even exhibited more severe inflammatory and atherosclerotic lesions. All these results suggest that Asm gene and related MR clustering are essential to endothelial inflammasome activation and dysfunction in carotid arteries, ultimately determining the extent of atherosclerotic lesions.

scholarly journals Palmitate aggravates proteinuria-induced cell death and inflammation via CD36-inflammasome axis in the proximal tubular cells of obese mice

2018 ◽  
Vol 315 (6) ◽  
pp. F1720-F1731 ◽  
Author(s):  
Lung-Chih Li ◽  
Jenq-Lin Yang ◽  
Wen-Chin Lee ◽  
Jin-Bor Chen ◽  
Chien-Te Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Tubular Injury ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Caspase 1 ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Nlrp3 Inflammasomes

High levels of serum free fatty acids (FFAs) and proteinuria have been implicated in the pathogenesis of obesity-related nephropathy. CD36, a class B scavenger receptor, is highly expressed in the renal proximal tubules and mediates FFA uptake. It is not clear whether FFA- and proteinuria-mediated CD36 activation coordinates NLRP3 inflammasomes to induce renal tubular injury and inflammation. In this study, we investigated the roles of CD36 and NLRP3 inflammasomes in FFA-induced renal injury in high-fat diet (HFD)-induced obesity. HFD-fed C57BL/6 mice and palmitate-treated HK2 renal tubular cells were used as in vivo and in vitro models. Immunohistochemical staining showed that CD36, IL-1β, and IL-18 levels increased progressively in the kidneys of HFD-fed mice. Sulfo- N-succinimidyl oleate (SSO), a CD36 inhibitor, attenuated the HFD-induced upregulation of NLRP3, IL-1β, and IL-18 and suppressed the colocalization of NLRP3 and ASC in renal tubular cells. In vitro, SSO abolished the palmitate-induced activation of IL-1β, IL-18, and caspase-1 in HK2 proximal tubular cells. Furthermore, treatment with SSO and the knockdown of caspase-1 expression by siRNA both inhibited palmitate-induced cell death and apoptosis in HK2 cells. Collectively, palmitate causes renal tubular inflammation, cell death, and apoptosis via the CD36/NLRP3/caspase-1 axis, which may explain, at least in part, the mechanism underlying FFA-related renal tubular injury. The blockade of CD36-induced cellular processes is therefore a promising strategy for treating obesity-related nephropathy.

scholarly journals Silibinin Downregulates the NF-κB Pathway and NLRP1/NLRP3 Inflammasomes in Monocytes from Pregnant Women with Preeclampsia

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1548 ◽  
Author(s):  
Mariana Leticia Matias ◽  
Virginia Juliani Gomes ◽  
Mariana Romao-Veiga ◽  
Vanessa Rocha Ribeiro ◽  
Priscila Rezeck Nunes ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Immunological Response ◽  
Response Characteristic ◽  
Sterile Inflammation ◽  
Blood Monocytes ◽  
Specific Syndrome ◽  
Tnf Α ◽  
Gene And Protein Expression ◽  
Nlrp3 Inflammasomes

Preeclampsia (PE) is a human pregnancy-specific syndrome with abnormal activation of cells from the innate immune system. The present study evaluated whether silibinin (SB) treatment of monocytes from preeclamptic women could modulate NLRP1 and NLRP3 inflammasomes as well as TLR4/NF-κB pathway activation. Peripheral blood monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, as well as the THP-1 cell line, were cultured with or without monosodium urate (MSU) or SB. NLRP1, NLRP3, Caspase-1, TLR4, MyD88, NF-κB, IL-1β, IL-18, TNF-α and IL-10 gene expression by monocytes was analysed by quantitative real-time polymerase chain reaction (qPCR), while inflammatory cytokine production and p65NF-κB activity were determined by enzyme-linked immunosorbent assays (ELISAs). TLR4/MyD88/NF-κB and NLRP1/NLRP3 inflammasomes pathways in THP-1 cells were evaluated by flow cytometry and western blot respectively. Compared with NT women, monocytes from preeclamptic women showed The Ethics Committee of the Botucatu Medical School approved the study (protocol number 2.333.216)higher endogenous activation of NLRP1/NLRP3 inflammasomes and the TLR4/NF-κB pathway as well as higher gene and protein expression of IL-1β, IL-18 and TNF-α, and lower expression of IL-10. Monocyte stimulation with MSU increased inflammation-related genes as well as NF-κB activity. In vitro, SB treatment of monocytes from preeclamptic women reduced the basal activation of these cells by decreasing NLRP1/NLRP3 inflammasomes and p65NF-κB activity. THP-1 cells exhibited a similar immunological response profile to monocytes from preeclamptic women when cultured with or without MSU or SB. These results suggest uric acid participates in the systemic inflammatory response characteristic of preeclampsia and that in vitro SB treatment can modulate the sterile inflammation established in monocytes from preeclamptic women.

scholarly journals Essential role of Salmonella Enteritidis DNA adenine methylase in modulating inflammasome activation

2020 ◽  
Author(s):  
Yaxin Guo ◽  
Dan Gu ◽  
Tingting Huang ◽  
Liyan Cao ◽  
Xinyu Zhu ◽  
...  
Keyword(s):  
Salmonella Enteritidis ◽  
Essential Role ◽  
Inflammasome Activation ◽  
Immunological Mechanisms ◽  
Dna Adenine Methylase ◽  
Lentiviral Infection ◽  
Infected Cells ◽  
Potential Factors ◽  
Nlrp3 Inflammasomes

Abstract Background: Salmonella Enteritidis (SE) is one of the major foodborne zoonotic pathogens of worldwide importance which can induce activation of NLRC4 and NLRP3 inflammasomes during infection. Given that the inflammasomes play an essential role in resisting bacterial infection, Salmonella has evolved various strategies to regulate activation of the inflammasome, most of which largely remain unclear.Results: A transposon mutant library in SE strain C50336 was screened for the identification of the potential factors that regulate inflammasome activation. We found that T3SS-associated genes invC, prgH, and spaN were required for inflammasome activation in vitro. Interestingly, C50336 strains with deletion or overexpression of Dam were both defective in activation of caspase-1 and secretion of IL-1β. Transcriptome sequencing (RNA-seq) results suggest that the absence and overexpression of Dam had similar effects on infected cells, as high overlapping rates of differentially expressed genes and enriched pathways were found between the C50336-VS-C50336Δdam and C50336-VS-C50336::dam groups, including multiple signaling pathways related to the inflammasome. Moreover, overexpression of Dam in macrophages by lentiviral infection could specifically promote the activation of the NLRP3 inflammasome independently.Conclusions: These data indicate that Dam was essential for modulating inflammasome activation during SE infection, there are complex and dynamic interplays between Dam and the inflammasome under different conditions. New insights were provided about the battle between SE and host innate immunological mechanisms.

Curcumin Management of Myocardial Fibrosis and its Mechanisms of Action: A Review

2019 ◽  
Vol 47 (08) ◽  
pp. 1675-1710 ◽  
Author(s):  
Yonghui Yu ◽  
Jinghui Sun ◽  
Ru Wang ◽  
Jiangang Liu ◽  
Peili Wang ◽  
...  
Keyword(s):  
Myocardial Fibrosis ◽  
Cardiac Fibrosis ◽  
Cardiac Injury ◽  
Volume Overload ◽  
Curcumin Analogs ◽  
Natural Polyphenol ◽  
Anti Oxidant ◽  
Nlrp3 Inflammasomes

Myocardial fibrosis is implicated as a leading risk factor for heart failure, arrhythmia, and sudden death after cardiac injury, as the excessive interstitial extracellular matrix impedes heart contraction and electrical conduction. Complicated mechanisms involving oxidative stress, pro-inflammatory cytokines, chemokine families, NLRP3 inflammasomes, growth factors, and non-coding RNAs participate in cardiac fibrogenesis and make it difficult to designate specific and effective therapies. Oriental herbs have been popular for thousands of years in the health care of Asian residents, due to their multi-targeted, multi-faceted approaches and their multi-functional effects in fighting difficult and complicated diseases, including cardiovascular disorders such as myocardial fibrosis. Curcumin, a natural polyphenol and yellow pigment obtained from the spice turmeric, was found to have strong anti-oxidant and anti-inflammatory properties. Increasing evidence has shown that curcumin can be used to prevent and treat myocardial fibrosis, when the myocardium suffers pathological pro-fibrotic changes in vivo and in vitro. The present review focuses on recent studies elucidating the mechanisms of curcumin in treating different pathologic conditions, including ischemia, hypoxia/reoxygenation, pressure or volume overload, and hyperglycemia or high-fat-induced cardiac fibrosis. Novel analogs such as C66, B2BrBC, Y20, and J17 have been designed to maximize the therapeutic potentials of curcumin. These optimized curcumin analogs with improved bioavailability and pharmacokinetic profiles need to be clinically verified before curcumin could be recommended for the treatment of myocardial fibrosis.

Microglia NLRP3 Inflammasomes Activation Involving Diabetic Neuroinflammation in Diabetic Mice and BV2 Cells

2021 ◽  
Vol 27 ◽  
Author(s):  
Yuan Li ◽  
Haifeng Zhang ◽  
Mingyuan Liu ◽  
Weiying Guo ◽  
Lu Yu
Keyword(s):  
Proinflammatory Cytokines ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Diabetic Mice ◽  
Continuous Release ◽  
Bv2 Cells ◽  
Physiological Values ◽  
Nlrp3 Inflammasomes

Background: Hyperglycemia-induced microglia activation can cause a continuous release of proinflammatory cytokines, which gradually damages neurons and contributes to central diabetic neuroinflammation. Objective: This study aimed to illustrate the possible mechanism related to NLRP3 inflammasome and the aggravation of diabetes neuroinflammation. Methods: The targeted proteins from BV2 cells and brain tissues were tested by Western blot or immunohistochemistry. Cytokines from cell supernatant and serum were detected by ELISA. Meanwhile, cytoplasm and mitochondria ROS were determined by DCFHDA and Mito sox Red, respectively. Results: In vitro, BV2 cells were stimulated by different glucose concentrations (5.5 to 65 mM/L) above physiological values and maintained for different periods (12 to 48h). The proinflammatory cytokines IL-1β，IL18，IL6，TNFα and cytoplasm ROS were significantly increased in a dose-dependent manner, while mitochondrial ROS was unaffected. NLRP3 inflammasomes, MAPKs, and NF-κB pathways were obviously activated at the concentration of 35 mM/L for 12h. Inhibition assay using specific inhibitors indicated that the treatment of glucose (35 mM/L for 12h) could stimulate NLRP3 inflammasome activation via ROS/JNK MAPKs/NF-κB pathway. In STZ induced diabetes mice models, microglia NLRP3, ASC, and caspase-1 proteins were highly expressed, and serum cytokines IL-1β, IL6, IL18, and TNFα were remarkably increased. Conclusion: Microglia NLRP3 inflammasomes activation involves diabetic neuroinflammation in diabetic mice and BV2 cells via ROS/JNK MAPKs/NF-κB pathways.

scholarly journals Macrolides protect against Pseudomonas aeruginosa infection via inhibition of inflammasomes

2017 ◽  
Vol 313 (4) ◽  
pp. L677-L686 ◽  
Author(s):  
Li-Chao Fan ◽  
Jie-Lu Lin ◽  
Jia-Wei Yang ◽  
Bei Mao ◽  
Hai-Wen Lu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lung Injury ◽  
Treatment Options ◽  
Therapeutic Effects ◽  
Bacterial Clearance ◽  
Pseudomonas Aeruginosa Infection ◽  
Related Proteins ◽  
Nlrp3 Inflammasomes ◽  
Chronic Lung Infection

Macrolides antibiotics have been effectively used in many chronic diseases, especially with Pseudomonas aeruginosa (P. aeruginosa) infection. The mechanisms underlying the therapeutic effects of macrolides in these diseases remain poorly understood. We established a mouse model of chronic lung infection using P. aeruginosa agar-beads, with azithromycin treatment or placebo. Lung injury, bacterial clearance, and inflammasome-related proteins were measured. In vitro, the inflammasomes activation induced by flagellin or ATP were assessed in LPS-primed macrophages with or without macrolides treatment. Plasma IL-18 levels were determined from patients who were diagnosed with bronchiectasis isolated with or without P. aeruginosa and treated with azithromycin for 3–5 days. Azithromycin treatment enhanced bacterial clearance and attenuated lung injury in mice chronically infected with P. aeruginosa, which resulted from the inhibition of caspase-1-dependent IL-1β and IL-18 secretion. In vitro, azithromycin and erythromycin inhibited NLRC4 and NLRP3 inflammasomes activation. Plasma IL-18 levels were higher in bronchiectasis patients with P. aeruginosa isolation compared with healthy controls. Azithromycin administration markedly decreased IL-18 secretion in bronchiectasis patients. The results of this study reveal that azithromycin and erythromycin exert a novel anti-inflammatory effect by attenuating inflammasomes activation, which suggests potential treatment options for inflammasome-related diseases.

scholarly journals hucMSC-derived exosomes attenuate colitis by regulating macrophage pyroptosis via the miR-378a-5p/NLRP3 axis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiu Cai ◽  
Zhi-yu Zhang ◽  
Jin-tao Yuan ◽  
Dickson Kofi Wiredu Ocansey ◽  
Qiang Tu ◽  
...  
Keyword(s):  
Peritoneal Macrophages ◽  
Human Umbilical Cord ◽  
Inflammatory Reactions ◽  
Pyrin Domain ◽  
Inflammatory Bowel ◽  
Nlrp3 Inflammasomes ◽  
Mouse Peritoneal Macrophages

Abstract Background Human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes are recognized as novel cell-free therapeutic agents for inflammatory bowel disease (IBD), a condition caused by dysregulated intestinal mucosal immunity. In this event, macrophage pyroptosis, a process of cell death following the activation of NLRP3 (NOD-like receptor family, pyrin domain-containing 3) inflammasomes, is believed to partially account for inflammatory reactions. However, the role of macrophage pyroptosis in the process of hucMSC-derived exosomes alleviating colitis remains unknown. This study aimed at exploring the therapeutic effect and mechanism of hucMSC-derived exosomes on colitis repair. Methods In vivo, we used BALB/c mice to establish a dextran sulfate sodium (DSS)-induced colitis model and administrated hucMSC-derived exosomes intravenously to estimate its curative effect. Human myeloid leukemia mononuclear (THP-1) cells and mouse peritoneal macrophages (MPMs) were stimulated with lipopolysaccharides (LPS) and Nigericin to activate NLRP3 inflammasomes, which simulated an inflammation environment in vitro. A microRNA mimic was used to verify the role of miR-378a-5p/NLRP3 axis in the colitis repair. Results hucMSC-derived exosomes inhibited the activation of NLRP3 inflammasomes in the mouse colon. The secretion of interleukin (IL)-18, IL-1β, and Caspase-1 cleavage was suppressed, resulting in reduced cell pyroptosis. The same outcome was observed in the in vitro cell experiments, where the co-culture of THP-1 cells and MPMs with hucMSC-derived exosomes caused decreased expression of NLRP3 inflammasomes and increased cell survival. Furthermore, miR-378a-5p was highly expressed in hucMSC-derived exosomes and played a vital function in colitis repair. Conclusion hucMSC-derived exosomes carrying miR-378a-5p inhibited NLRP3 inflammasomes and abrogated cell pyroptosis to protect against DSS-induced colitis.

Avoidance of the NLRP3 Inflammasome by the Stealth Pathogen, Coxiella burnetii

2020 ◽  
pp. 030098582098136
Author(s):  
Martha A. Delaney ◽  
Andreas den Hartigh ◽  
Samuel J. Carpentier ◽  
Timothy P. Birkland ◽  
Donald P. Knowles ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Bacterial Pathogen ◽  
In Vivo Model ◽  
Caspase 1 ◽  
Type Iv ◽  
Clinical Resistance ◽  
Nlrp3 Inflammasomes

Coxiella burnetii, a highly adapted obligate intracellular bacterial pathogen and the cause of the zoonosis Q fever, is a reemerging public health threat. C. burnetii employs a Type IV secretion system (T4SS) to establish and maintain its intracellular niche and modulate host immune responses including the inhibition of apoptosis. Interactions between C. burnetii and caspase-1-mediated inflammasomes are not fully elucidated. This study confirms that C. burnetii does not activate caspase-1 during infection of mouse macrophages in vitro. C. burnetii–infected cells did not develop NLRP3 and ASC foci indicating its ability to avoid cytosolic detection. C. burnetii is unable to inhibit the pyroptosis and IL-1β secretion that is induced by potent inflammasome stimuli but rather enhances these caspase-1-mediated effects. We found that C. burnetii upregulates pro-IL-1β and robustly primes NLRP3 inflammasomes via TLR2 and MyD88 signaling. As for wildtype C. burnetii, T4SS-deficient mutants primed and potentiated NLRP3 inflammasomes. An in vivo model of pulmonary infection in C57BL/6 mice was developed. Mice deficient in NLRP3 or caspase-1 were like wildtype mice in the development and resolution of splenomegaly due to red pulp hyperplasia, and histologic lesions and macrophage kinetics, but had slightly higher pulmonary bacterial burdens at the greatest measured time point. Together these findings indicate that C. burnetii primes but avoids cytosolic detection by NLRP3 inflammasomes, which are not required for the clinical resistance of C57BL/6 mice. Determining mechanisms employed by C. burnetii to avoid cytosolic detection via NLRP3 inflammasomes will be beneficial to the development of preventative and interventional therapies for Q fever.

scholarly journals IL-18 and IL-18 binding protein are related to disease severity and parasitemia during falciparum malaria

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kari Otterdal ◽  
Aase Berg ◽  
Annika E. Michelsen ◽  
Arne Yndestad ◽  
Sam Patel ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Falciparum Malaria ◽  
Disease Severity ◽  
Cell Activation ◽  
Binding Protein ◽  
Endothelial Cell Activation ◽  
Inflammatory Molecules ◽  
Nlrp3 Inflammasomes

Abstract Background Several inflammatory molecules participate in the immune response to malaria. Interleukin (IL)-18 is an inflammatory cytokine activated by NLRP3 inflammasomes. In clinical falciparum malaria, with and without HIV co-infection, data on IL-18 and in particular on its binding protein, IL-18bp, is scarce. Methods Clinical data and blood samples were collected from adults in Mozambique with P. falciparum infection, with (n = 70) and without (n = 61) HIV co-infection, from HIV-infected patients with similar symptoms without malaria (n = 58) and from healthy controls (n = 52). In vitro studies were performed in endothelial cells using hemozoin crystals. Results (i) IL-18 and IL-18bp were markedly up-regulated during falciparum malaria with particular high levels in malaria patients co-infected with HIV and severe malaria disease. (ii) In the malaria group as a whole, both IL-18 and IL-18bp were positively correlated with disease severity, parasitemia, and endothelial cell activation as assessed by vWF in plasma. (iii) Whereas there was no change in IL-18 levels in malaria patients co-infected with HIV during follow-up, the patients with malaria only had slightly increased IL-18 levels. Further, the IL-18pb levels declined and thereby contributed to an increase in IL-18/IL-18bp ratio in all subgroups of malaria patients. (iv) IL-27, previously shown to be up-regulated in this malaria cohort, markedly induced a release of IL-18bp from endothelial cells in vitro, and notably, this presumably anti-inflammatory effect was counteracted by hemozoin. Conclusions Our findings suggest that the IL-18 system could be an important mediator in the immune pathogenesis during falciparum malaria, potentially also representing a target for therapy.

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