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 ◽  
...  

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.

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 ◽  
...  

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.


2020 ◽  
Author(s):  
Zhiquan Zhang ◽  
Qing Ma ◽  
Ravikanth Velagapudi ◽  
William E. Barclay ◽  
Ramona M. Rodriguiz ◽  
...  

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Elisa Benetti ◽  
Fausto Chiazza ◽  
Nimesh S. A. Patel ◽  
Massimo Collino

The combination of obesity and type 2 diabetes is a serious health problem, which is projected to afflict 300 million people worldwide by 2020. Both clinical and translational laboratory studies have demonstrated that chronic inflammation is associated with obesity and obesity-related conditions such as insulin resistance. However, the precise etiopathogenetic mechanisms linking obesity to diabetes remain to be elucidated, and the pathways that mediate this phenomenon are not fully characterized. One of the most recently identified signaling pathways, whose activation seems to affect many metabolic disorders, is the “inflammasome,” a multiprotein complex composed of NLRP3 (nucleotide-binding domain and leucine-rich repeat protein 3), ASC (apoptosis-associated speck-like protein containing a CARD), and procaspase-1. NLRP3 inflammasome activation leads to the processing and secretion of the proinflammatory cytokines interleukin- (IL-) 1βand IL-18. The goal of this paper is to review new insights on the effects of the NLRP3 inflammasome activation in the complex mechanisms of crosstalk between different organs, for a better understanding of the role of chronic inflammation in metabolic disease pathogenesis. We will provide here a perspective on the current research on NLRP3 inflammasome, which may represent an innovative therapeutic target to reverse the detrimental metabolic consequences of the metabolic inflammation.


2019 ◽  
Vol 118 ◽  
pp. 109217 ◽  
Author(s):  
Jinlong Wei ◽  
Heru Wang ◽  
Huanhuan Wang ◽  
Bin Wang ◽  
Lingbin Meng ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Merry W. Ma ◽  
Jing Wang ◽  
Krishnan M. Dhandapani ◽  
Darrell W. Brann

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. After the initial primary mechanical injury, a complex secondary injury cascade involving oxidative stress and neuroinflammation follows, which may exacerbate the injury and complicate the healing process. NADPH oxidase 2 (NOX2) is a major contributor to oxidative stress in TBI pathology, and inhibition of NOX2 is neuroprotective. The NLRP3 inflammasome can become activated in response to oxidative stress, but little is known about the role of NOX2 in regulating NLRP3 inflammasome activation following TBI. In this study, we utilized NOX2 knockout mice to study the role of NOX2 in mediating NLRP3 inflammasome expression and activation following a controlled cortical impact. Expression of NLRP3 inflammasome components NLRP3 and apoptosis-associated speck-like protein containing a CARD (ASC), as well as its downstream products cleaved caspase-1 and interleukin-1β (IL-1β), was robustly increased in the injured cerebral cortex following TBI. Deletion of NOX2 attenuated the expression, assembly, and activity of the NLRP3 inflammasome via a mechanism that was associated with TXNIP, a sensor of oxidative stress. The results support the notion that NOX2-dependent inflammasome activation contributes to TBI pathology.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e17028-e17028 ◽  
Author(s):  
Yuan-Ru Chen ◽  
Hsin-Chih Yeh ◽  
Fang-Yen Chiu ◽  
Hsin-En Wu ◽  
Huei-Chen Fang ◽  
...  

e17028 Background: Bladder cancer is one of the most common malignancies of urinary system with the forth incidence rate and the eighth leading mortality rate in male genitourinary tumors. Hypoxia environment activates the hypoxia‐signalling pathway, principally via hypoxia‐inducible transcription factors (HIF) to activate numerous target genes which mediate embryonic vascularization, metabolism, tumor angiogenesis and the other processes to supply tissues with blood and oxygen. Inflammasomes are multiprotein signal responsible for the maturation of proinflammatory cytokines IL-1β and IL-18 as well as trigger the inflammatory cell pyroptosis. Recent study showed that HIF-1α promotes NLRP3 inflammasome activation in bleomycin-induced acute lung injury. However, the role of HIF1α in regulating the progression of bladder cancer has not been examined so far. The present study aimed to investigate the effect of HIF-1α on NLRP3 inflammasome activation in urothelial carcinoma. Methods: In this research, urothelial carcinoma cell lines were treated with NLRP3 inflammasome inducers, LPS/ATP, to induce NLRP3 inflammasome activation. Results: Our preliminary results showed that both T24 and 5637 bladder cancer cells can be induced NLRP3 inflammasome activation and IL-1β secretion. In addition, hypoxia also induces the secretion of IL-1β in T24 cells. We further investigated the effect of NLRP3 inflammasome activation in modulating EMT-related protein levels, migration and invasion in bladder cancer T24 cells. Our results demonstrated that NLRP3 inflammasome activation promotes tumor growth and metastasis in bladder cancer cells. Furthermore, knockdown of HIF1α reduces both inflammatory response and migratory activity in bladder cancer. Conclusions: Collectively, these results suggest that targeting NLRP3 inflammasome might offer potential to treat hypoxic malignant tumor in bladder carcinoma.


2013 ◽  
Vol 231 (3) ◽  
pp. 342-353 ◽  
Author(s):  
Anna Solini ◽  
Stefano Menini ◽  
Chiara Rossi ◽  
Carlo Ricci ◽  
Eleonora Santini ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ralph A. Pietrofesa ◽  
Patrick Woodruff ◽  
Wei-Ting Hwang ◽  
Priyal Patel ◽  
Shampa Chatterjee ◽  
...  

Background. The interaction of asbestos with macrophages drives two key processes that are linked to malignancy: (1) the generation of reactive oxygen species (ROS)/reactive nitrogen species (RNS) and (2) the activation of an inflammation cascade that drives acute and chronic inflammation, with the NLRP3 inflammasome playing a key role. Synthetic secoisolariciresinol diglucoside (SDG), LGM2605, is a nontoxic lignan with anti-inflammatory and antioxidant properties and was evaluated for protection from asbestos in murine peritoneal macrophages (MF).Methods. MFs were exposed to crocidolite asbestos ± LGM2605 given 4 hours prior to exposure and evaluated at various times for NLRP3 expression, secretion of inflammasome-activated cytokines (IL-1βand IL-18), proinflammatory cytokines (IL-6, TNFα, and HMGB1), NF-κB activation, and levels of total nitrates/nitrites.Results. Asbestos induces a significant (p<0.0001) increase in the NLRP3 subunit, release of proinflammatory cytokines, NLRP3-activated cytokines, NF-κB, and levels of nitrates/nitrites. LGM2605 significantly reduced NLRP3 ranging from 40 to 81%, IL-1βby 89–96%, and TNFαby 67–78%, as well as activated NF-κB by 48-49% while decreasing levels of nitrates/nitrites by 85–93%.Conclusions. LGM2605 reduced asbestos-induced NLRP3 expression, proinflammatory cytokine release, NF-κB activation, and nitrosative stress in MFs supporting its possible use in preventing the asbestos-induced inflammatory cascade leading to malignancy.


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