scholarly journals Role of Annexin A1 in NLRP3 Inflammasome Activation in Murine Neutrophils

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 121
Author(s):  
José Marcos Sanches ◽  
Rebeca D. Correia-Silva ◽  
Gustavo H. B. Duarte ◽  
Anna Maria A. P. Fernandes ◽  
Salvador Sánchez-Vinces ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Nlrp3 Inflammasome ◽  
Cell Stress ◽  
Lipid Biomarkers ◽  
Inflammasome Activation ◽  
Annexin A1 ◽  
Wild Type ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

This study evaluated the role of endogenous and exogenous annexin A1 (AnxA1) in the activation of the NLRP3 inflammasome in isolated peritoneal neutrophils. C57BL/6 wild-type (WT) and AnxA1 knockout mice (AnxA1-/-) received 0.3% carrageenan intraperitoneally and, after 3 h, the peritoneal exudate was collected. WT and AnxA1-/- neutrophils were then stimulated with lipopolysaccharide, followed by the NLRP3 agonists nigericin or ATP. To determine the exogenous effect of AnxA1, the neutrophils were pretreated with the AnxA1-derived peptide Ac2-26 followed by the NLRP3 agonists. Ac2-26 administration reduced NLRP3-derived IL-1β production by WT neutrophils after nigericin and ATP stimulation. However, IL-1β release was impaired in AnxA1-/- neutrophils stimulated by both agonists, and there was no further impairment in IL-1β release with Ac2-26 treatment before stimulation. Despite this, ATP- and nigericin-stimulated AnxA1-/- neutrophils had increased levels of cleaved caspase-1. The lipidomics of supernatants from nigericin-stimulated WT and AnxA1-/- neutrophils showed potential lipid biomarkers of cell stress and activation, including specific sphingolipids and glycerophospholipids. AnxA1 peptidomimetic treatment also increased the concentration of phosphatidylserines and oxidized phosphocholines, which are lipid biomarkers related to the inflammatory resolution pathway. Together, our results indicate that exogenous AnxA1 negatively regulates NLRP3-derived IL-1β production by neutrophils, while endogenous AnxA1 is required for the activation of the NLRP3 machinery.

scholarly journals Annexin A1 Regulates NLRP3 Inflammasome Activation and Modifies Lipid Release Profile in Isolated Peritoneal Macrophages

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 926 ◽  
Author(s):  
José Marcos Sanches ◽  
Laura Migliari Branco ◽  
Gustavo Henrique Bueno Duarte ◽  
Sonia Maria Oliani ◽  
Karina Ramalho Bortoluci ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Peritoneal Macrophages ◽  
Lipid Mediator ◽  
Inflammasome Activation ◽  
Annexin A1 ◽  
Wild Type ◽  
Inflammatory Protein ◽  
Nlrp3 Inflammasome Activation ◽  
Macrophage Viability

Annexin A1 (AnxA1) is a potent anti-inflammatory protein that downregulates proinflammatory cytokine release. This study evaluated the role of AnxA1 in the regulation of NLRP3 inflammasome activation and lipid release by starch-elicited murine peritoneal macrophages. C57bl/6 wild-type (WT) and AnxA1-null (AnxA1-/-) mice received an intraperitoneal injection of 1.5% starch solution for macrophage recruitment. NLRP3 was activated by priming cells with lipopolysaccharide for 3 h, followed by nigericin (1 h) or ATP (30 min) incubation. As expected, nigericin and ATP administration decreased elicited peritoneal macrophage viability and induced IL-1β release, more pronounced in the AnxA1-/- cells than in the control peritoneal macrophages. In addition, nigericin-activated AnxA1-/- macrophages showed increased levels of NLRP3, while points of co-localization of the AnxA1 protein and NLRP3 inflammasome were detected in WT cells, as demonstrated by ultrastructural analysis. The lipidomic analysis showed a pronounced release of prostaglandins in nigericin-stimulated WT peritoneal macrophages, while ceramides were detected in AnxA1-/- cell supernatants. Different eicosanoid profiles were detected for both genotypes, and our results suggest that endogenous AnxA1 regulates the NLRP3-derived IL-1β and lipid mediator release in macrophages.

Abstract 127: Txnip-Mediated NLRP3 Inflammasome Activation as a Novel Mechanism of Myocardial Ischemia-Reperfusion Injury

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Yi Liu ◽  
Lijian Zhang ◽  
Yan Qu ◽  
Chao Gao ◽  
Jingyi Liu ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion ◽  
Inflammatory Cells ◽  
Inflammasome Activation ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation ◽  
Myocardial Ischemia Reperfusion

As an inhibitor of the antioxidant thioredoxin, thioredoxin-interacting protein (Txnip) is linked to insulin resistance. NLRP3 inflammasome, a major regulator of innate immunity, has been reported to be activated by Txnip, thus contributing to the pathogenesis of type 2 diabetes mellitus. However, the role of Txnip and its NLRP3 inflammasome activation in the myocardial ischemia/reperfusion (MI/R) injury has not been previously investigated. C57BL/6J mice were subjected to 30 min of ischemia and 3 or 24 hrs of reperfusion. The ischemic heart exhibited increased Txnip and NLRP3 expressions, increased interaction between Txnip and NLRP3 (by immunoprecipitation, 1.8-fold increase over sham), and increased IL-1β, IL-18 and caspase-1 expressions (%increase: 80%, 77% and 110%, respectively) (n=8, all P <0.05). Compared with vehicle group, those mice either receiving intramyocardial small-interfering RNA (siRNA) injection to specifically knockdown the myocardial NLRP3 or intraperitoneal injection of the inflammasome inhibitor (BAY 11-7082) exhibited significantly improved cardiac function (by 28% and 25%), decreased the infarct size (by 40% and 38%), and decreased the cardiomyocytes apoptosis (all P <0.05). NLRP3 knockdown or inflammasome inhibitor also decreased the inflammatory cells infiltration (macrophages and neutrophils) and cytokines (TNF-α, INF-γ and IL-6) production (all P <0.05). To elucidate the role of Txnip in the NLRP3 activation in MI/R, intramyocardial injection of Txnip siRNA was performed to specifically knockdown the myocardial Txnip expression. Compared with vehicle, the Txnip knockdown significantly decreased Txnip/NLRP3 interaction and NLRP3activation as evidenced by lower expressions of IL-1β and caspase-1, decreased inflammatory cells infiltration and cytokines expressions, and consequently decreased the myocardial infarct size and increased the heart function (all P <0.05). Collectively, we demonstrated for the first time that Txnip mediatedNLRP3 inflammasome activation is a novel mechanism of MI/R injury. Interventions targeted to blocking the activation of NLRP3 by inhibiting Txnip may have therapeutic potential for preventing MI/R injury.

NLRP3 inflammasome activation contributes to aldosterone-induced podocyte injury

2017 ◽  
Vol 312 (4) ◽  
pp. F556-F564 ◽  
Author(s):  
Mi Bai ◽  
Ying Chen ◽  
Min Zhao ◽  
Yue Zhang ◽  
John Ci-Jiang He ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Renal Tubules ◽  
Mineralocorticoid Receptor Antagonist ◽  
Podocyte Injury ◽  
Nlrp3 Gene ◽  
Caspase 1 ◽  
Focal Segmental Glomerular Sclerosis ◽  
Nlrp3 Inflammasome Activation

Aldosterone (Aldo) has been shown as an important contributor of podocyte injury. However, the underlying molecular mechanisms are still elusive. Recently, the pathogenic role of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in mediating renal tubular damage was identified while its role in podocyte injury still needs evidence. Thus the present study was undertaken to investigate the role of NLRP3 inflammasome in Aldo-induced podocyte damage. In vitro, exposure of podocytes to Aldo enhanced NLRP3, caspase-1, and IL-18 expressions in dose- and time-dependent manners, indicating an activation of NLRP3 inflammasome, which was significantly blocked by the mineralocorticoid receptor antagonist eplerenone or the antioxidant N-acetylcysteine. Silencing NLRP3 by a siRNA approach strikingly attenuated Aldo-induced podocyte apoptosis and nephrin protein downregulation in line with the blockade of caspase-1 and IL-18. In vivo, since day 5 of Aldo infusion, NLRP3 inflammasome activation and podocyte injury evidenced by nephrin reduction occurred concurrently. More importantly, immunofluorescence analysis showed a significant induction of NLRP3 in podocytes of glomeruli following Aldo infusion. In the mice with NLRP3 gene deletion, Aldo-induced downregulation of nephrin and podocin, podocyte foot processes, and albuminuria was remarkably improved, indicating an amelioration of podocyte injury. Finally, we observed a striking induction of NLRP3 in glomeruli and renal tubules in line with an enhanced urinary IL-18 output in nephrotic syndrome patients with minimal change disease or focal segmental glomerular sclerosis. Together, these results demonstrated an important role of NLRP3 inflammasome in mediating the podocyte injury induced by Aldo.

scholarly journals Role of ASM/Cer/TXNIP signaling module in the NLRP3 inflammasome activation

2020 ◽  
Author(s):  
Jianjun Jiang ◽  
Jin Yang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Underlying Mechanism ◽  
Acid Sphingomyelinase ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Mrna Levels ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

Abstract Background: The NOD-Like Receptor Protein 3 (NLRP3) inflammasome is a crucial component of an array of inflammatory conditions. It functions by boosting the secretion of pro-inflammatory cytokines: interleukin-1β (IL-1β) and interleukin-18 (IL-18). Previous studies have established the vital role of the acid sphingomyelinase (ASM)/ceramide (Cer) pathway in the functional outcome of cells, with a particular emphasis on the inflammatory processes. This study aimed to explore the effects and associated underlying mechanism of Cer-induced NLRP3 inflammasome activation.Methods: Lipopolysaccharide (LPS)/adenosine triphosphate (ATP)-induced NLRP3 inflammasome activation in J774A.1 cells was used as an in vitro inflammatory model. Western blotting and Real-time PCR (RT-PCR) were used to detect the protein and mRNA levels, respectively. IL-1β and IL-18 levels were evaluated using ELISA kits. ASM assay kit and immunofluorescence were used to detect ASM activity and Cer content.Results: Imipramine, a well-known inhibitor of ASM, significantly inhibited ASM activity and inhibited Cer accumulation, which indicated ASM activation. Besides, it also suppressed the LPS/ATP-induced expression of proteins and mRNA: thioredoxin interacting protein (TXNIP), NLRP3, caspase-1, IL-1β and IL-18. Interestingly verapamil, a TXNIP inhibitor, suppressed LPS/ATP-induced TXNIP/NLRP3 inflammasome activation; however, it did not affect LPS/ATP-induced ASM activation and ceramide production. Further analysis showed that the exogenous C2-Cer treated J774A.1 cells induced the overexpression of TXNIP, NLRP3, caspase-1, IL-1β and IL-18. Besides, TXNIP siRNA or verapamil inhibited C2-Cer-induced TXNIP overexpression and NLRP3 inflammasome activation.Conclusion: This study demonstrated the involvement of the ASM/Cer/TXNIP signaling pathway in NLRP3 inflammasome activation.

scholarly journals Annexin-A1 tripeptide attenuates surgery-induced neuroinflammation and memory deficits through regulation of the NLRP3 inflammasome

2020 ◽  
Author(s):  
Zhiquan Zhang ◽  
Qing Ma ◽  
Ravikanth Velagapudi ◽  
William E. Barclay ◽  
Ramona M. Rodriguiz ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Morphological Changes ◽  
Memory Deficits ◽  
Inflammasome Activation ◽  
Surgical Trauma ◽  
Annexin A1 ◽  
Neuroprotective Effects ◽  
Nlrp3 Inflammasome Activation ◽  
The Impact

AbstractNeuroinflammation is a growing hallmark of perioperative neurocognitive disorders (PNDs), including delirium and longer-lasting cognitive deficits. We have developed a clinically-relevant orthopedic mouse model to study the impact of a common surgical procedure on the vulnerable brain. The mechanism underlying PNDs remain unknown. Here we evaluated the impact of surgical trauma on the NLRP3 inflammasome signaling, including the expression of apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, and IL-1β in the hippocampus of C57BL6/J male mice, adult (3-months) and aged (>18-months). Surgery triggered ASC specks formation in CA1 hippocampal microglia, but without inducing significant morphological changes in NLRP3 and ASC knockout mice. Since no therapies are currently available to treat PNDs, we assessed the neuroprotective effects of a biomimetic peptide derived from the endogenous inflammation-ending molecule, Annexin-A1 (ANXA1). We tested the hypothesis that this peptide (ANXA1sp) inhibits NLRP3 inflammasome activation, thus preventing microglial activation and hippocampal-dependent memory deficits. Together these results uncover a previously underrecognized role of the NLRP3 inflammasome in triggering postoperative neuroinflammation and offer a new target for advancing treatment of PNDs through resolution of inflammation.

scholarly journals Role of NLRP3 Inflammasomes in Neuroinflammation Diseases

2020 ◽  
pp. 1-5
Author(s):  
Sen Lin ◽  
Xifan Mei
Keyword(s):  
Nlrp3 Inflammasome ◽  
Current Knowledge ◽  
Inflammasome Activation ◽  
Protein Signaling ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation ◽  
Inflammatory Immune Response ◽  
Nlrp3 Inflammasomes ◽  
Pro Inflammatory Cytokines

<b><i>Background:</i></b> Inflammasomes are large intracellular multi-protein signaling complexes that are formed in the cytosolic compartment as an inflammatory immune response to endogenous danger signals. The formation of the inflammasome enables activation of an inflammatory protease caspase-1 and pyroptosis initiation with the subsequent cleaving of the pro-inflammatory cytokines interleukin (IL)-1β and proIL-18 to produce active forms. The inflammasome complex consists of a nod-like receptor, the adapter apoptosis-associated speck-like protein, and caspase-1. Dysregulation of NLRP3 inflammasome activation is involved in neuroinflammation disease pathogenesis, although its role in SCI development and progression remains controversial due to the inconsistent findings described. <b><i>Summary:</i></b> In this review, we summarize the current knowledge on the contribution of the NLRP3 inflammasome on potential neuroinflammation diseases therapy.

scholarly journals Mul1 suppresses Nlrp3 inflammasome activation through ubiquitination and degradation of Asc

2019 ◽  
Author(s):  
June-Hyung Kim ◽  
Yunjong Lee ◽  
Gee Young Suh ◽  
Yun-Song Lee
Keyword(s):  
Inflammatory Response ◽  
Nlrp3 Inflammasome ◽  
Raw264.7 Cells ◽  
Inflammasome Activation ◽  
Wild Type ◽  
Ubiquitin Protein Ligase ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation ◽  
In The Wild ◽  
Excessive Inflammatory Response

AbstractActivation of the Nlrp3 inflammasome consisting of three major components, Nlrp3, Asc, and pro-caspase-1, results in the activation of caspase-1 and subsequent proteolytic cleavage of pro-IL-1β and pro-IL-18. To avoid excessive inflammatory response, the Nlrp3 inflammasome has to be precisely controlled. In this study, we show that the mouse mitochondrial E3 ubiquitin protein ligase (Mul1) suppresses Nlrp3 inflammasome activation through ubiquitination and degradation of Asc. In J774A.1 cells, Mul1 overexpression attenuated Nlrp3 activation, whereas Mul1 knockdown augmented Nlrp3 activation in terms of IL-1β secretion and cleavage of pro-caspase-1 and pro-IL-1β. Mul1 interacted with Asc, and ubiquitinated it at K21, K22, K26, and K55 residues, in a K48-linked manner, leading to proteasomal degradation. Convincingly, Mul1-mediated suppression of Nlrp3 activation was inhibited by K21R-, K22R-, K26R-, K52R-Asc mutants in RAW264.7 cells, when compared with the wild-type Asc. Furthermore, Aim2 inflammasome activation was also inhibited by Mul1 in the wild-type Asc-, but not in mutant Asc-expressing RAW264.7 cells. Taken together, these data suggest that Mul1 suppresses Nlrp3 inflammasome activation, through Asc ubiquitination and degradation.

scholarly journals Inhibiting the NLRP3 Inflammasome Activation with MCC950 Ameliorates Diabetic Encephalopathy in db/db Mice

Molecules ◽  
2018 ◽  
Vol 23 (3) ◽  
pp. 522 ◽  
Author(s):  
Yadong Zhai ◽  
Xiangbao Meng ◽  
Tianyuan Ye ◽  
Weijie Xie ◽  
Guibo Sun ◽  
...  
Keyword(s):  
Cognitive Dysfunction ◽  
Nlrp3 Inflammasome ◽  
Cognitive Disorders ◽  
Anxiety And Depression ◽  
Inflammasome Activation ◽  
Diabetic Encephalopathy ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

Diabetes is associated with a high risk of developing cognitive dysfunction and neuropsychiatric disabilities, and these disease symptomsare termed diabetic encephalopathy (DEP). Inflammation is involved in the development of DEP. The cleavage and maturation of the proinflammatory cytokine interleukin (IL)-1β is regulated by the NLRP3 inflammasome. Obese and type 2 diabetic db/db mice show anxiety- and depression-like behaviors and cognitive disorders associated with hippocampal inflammation. The purpose of this study was to explore the role of NLRP3 inflammasome in DEP. Results showed that expression levels of inflammasome components including NLRP3, apoptosis-associated speck-like protein (ASC), and caspase-1, as well as IL-1β in the hippocampus of diabetic db/db mice were higher than those of non-diabetic db/m mice. Treatment of db/db mice with NLRP3 inflammasome inhibitor MCC950 ameliorated anxiety- and depression-like behaviors as well as cognitive dysfunction, and reversed increased NLRP3, ASC, and IL-1βexpression levels and caspase-1 activity in hippocampus. Moreover, MCC950 treatment significantly improved insulin sensitivity in db/db mice. These results demonstrate that inhibition of NLRP3 inflammasome activation may prove to be a potential therapeutic approach for DEP treatment.

scholarly journals Role of ASM/Cer/TXNIP Signaling Module in the NLRP3 Inflammasome Activation

2020 ◽  
Author(s):  
Jianjun Jiang ◽  
Jin Yang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Drug Targets ◽  
Inflammatory Diseases ◽  
Acid Sphingomyelinase ◽  
Inflammasome Activation ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation ◽  
Ceramide Production

Abstract Background: The NLRP3 inflammasome serves as a crucial component in an array of inflammatory conditions by boosting the secretion of pro-inflammatory cytokines: IL-1β and IL-18. Hence, a thorough investigation of the underlying mechanism of NLRP3 activation could ascertain the requisite directionality to the ongoing studies, along with the identification of the novel drug targets for the management of inflammatory diseases. Previous studies have established the vital role of the Acid sphingomyelinase (ASM)/Ceramide (Cer) pathway in the functional outcome of cells, with a particular emphasis on the inflammatory processes. ASM mediates the ceramide production by sphingomyelin hydrolysis. Furthermore, the participation of the ASM/Cer in NLRP3 activation remains ambiguous. Methods: We employed lipopoysaccharide (LPS)/Adenosine Triphosphate (ATP)-induced activation of NLRP3 inflammasome in J774A.1 cells as an in vitro inflammatory model. Results: We observed that imipramine, a well-known inhibitor of ASM, significantly inhibited ASM activity & increased ceramide accumulation, which indicates ASM activation. Besides, it also suppressed the LPS/ATP-induced expression of proteins and mRNA: Thioredoxin interacting protein (TXNIP), NLRP3, Caspase-1, IL-1β and IL-18. Interestingly verapamil, a TXNIP inhibitor, suppressed LPS/ATP-induced TXNIP/NLRP3 inflammasome activation; however, it did not affect LPS/ATP-induced ASM activity and ceramide production. Further examination showed that the exogenous C2-ceramide-treated J774A.1 cells induce the overexpression of TXNIP, NLRP3, Caspase-1, IL-1β, and IL-18. Furthermore, verapamil inhibited C2-Ceramide mediated TXNIP overexpression and NLRP3 inflammasome activation. These findings infer that TXNIP overexpression leads to Cer mediated NLRP3 inflammasome activation. Conclusion: Our study validated the crucial role of the ASM/Cer/TXNIP signaling pathway in NLRP3 inflammasome activation.

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