scholarly journals Oxidative metabolism enables Salmonella evasion of the NLRP3 inflammasome

2014 ◽  
Vol 211 (4) ◽  
pp. 653-668 ◽  
Author(s):  
Meghan A. Wynosky-Dolfi ◽  
Annelise G. Snyder ◽  
Naomi H. Philip ◽  
Patrick J. Doonan ◽  
Maya C. Poffenberger ◽  
...  

Microbial infection triggers assembly of inflammasome complexes that promote caspase-1–dependent antimicrobial responses. Inflammasome assembly is mediated by members of the nucleotide binding domain leucine-rich repeat (NLR) protein family that respond to cytosolic bacterial products or disruption of cellular processes. Flagellin injected into host cells by invading Salmonella induces inflammasome activation through NLRC4, whereas NLRP3 is required for inflammasome activation in response to multiple stimuli, including microbial infection, tissue damage, and metabolic dysregulation, through mechanisms that remain poorly understood. During systemic infection, Salmonella avoids NLRC4 inflammasome activation by down-regulating flagellin expression. Macrophages exhibit delayed NLRP3 inflammasome activation after Salmonella infection, suggesting that Salmonella may evade or prevent the rapid activation of the NLRP3 inflammasome. We therefore screened a Salmonella Typhimurium transposon library to identify bacterial factors that limit NLRP3 inflammasome activation. Surprisingly, absence of the Salmonella TCA enzyme aconitase induced rapid NLRP3 inflammasome activation. This inflammasome activation correlated with elevated levels of bacterial citrate, and required mitochondrial reactive oxygen species and bacterial citrate synthase. Importantly, Salmonella lacking aconitase displayed NLRP3- and caspase-1/11–dependent attenuation of virulence, and induced elevated serum IL-18 in wild-type mice. Together, our data link Salmonella genes controlling oxidative metabolism to inflammasome activation and suggest that NLRP3 inflammasome evasion promotes systemic Salmonella virulence.

2013 ◽  
Vol 81 (8) ◽  
pp. 2997-3008 ◽  
Author(s):  
Wei Li ◽  
Barry P. Katz ◽  
Margaret E. Bauer ◽  
Stanley M. Spinola

ABSTRACTRecognition of microbial infection by certain intracellular pattern recognition receptors leads to the formation of a multiprotein complex termed the inflammasome. Inflammasome assembly activates caspase-1 and leads to cleavage and secretion of the proinflammatory cytokines interleukin-1 beta (IL-1β) and IL-18, which help control many bacterial pathogens. However, excessive inflammation mediated by inflammasome activation can also contribute to immunopathology. Here, we investigated whetherHaemophilus ducreyi, a Gram-negative bacterium that causes the genital ulcer disease chancroid, activates inflammasomes in experimentally infected human skin and in monocyte-derived macrophages (MDM). AlthoughH. ducreyiis predominantly extracellular during human infection, several inflammasome-related components were transcriptionally upregulated inH. ducreyi-infected skin. Infection of MDM with live, but not heat-killed,H. ducreyiinduced caspase-1- and caspase-5-dependent processing and secretion of IL-1β. Blockage ofH. ducreyiuptake by cytochalasin D significantly reduced the amount of secreted IL-1β. Knocking down the expression of the inflammasome components NLRP3 and ASC abolished IL-1β production. Consistent with NLRP3-dependent inflammasome activation, blocking ATP signaling, K+efflux, cathepsin B activity, and lysosomal acidification all inhibited IL-1β secretion. However, inhibition of the production and function of reactive oxygen species did not decrease IL-1β production. Polarization of macrophages to classically activated M1 or alternatively activated M2 cells abrogated IL-1β secretion elicited byH. ducreyi. Our study data indicate thatH. ducreyiinduces NLRP3 inflammasome activation via multiple mechanisms and suggest that the heterogeneity of macrophages within human lesions may modulate inflammasome activation during human infection.


2019 ◽  
Vol 147 ◽  
pp. 104348 ◽  
Author(s):  
Jiasi Wu ◽  
Yu Luo ◽  
Qing Jiang ◽  
Sheng Li ◽  
Wenge Huang ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Pengxiao Chen ◽  
Qi Bai ◽  
Yanting Wu ◽  
Qiongzhen Zeng ◽  
Xiaowei Song ◽  
...  

Artemisia argyi H. Lév. and Vaniot is a traditional medical herb that has been used for a long time in China and other Asian counties. Essential oil is the main active fraction of Artemisia argyi H. Lév. and Vaniot, and its anti-inflammatory potential has been observed in vitro and in vivo. Here, we found that the essential oil of Artemisia argyi H. Lév. and Vaniot (EOAA) inhibited monosodium urate (MSU)- and nigericin-induced NLRP3 inflammasome activation. EOAA suppressed caspase-1 and IL-1β processing and pyroptosis. NF-κB p65 phosphorylation and translocation were also inhibited. In addition, EOAA suppressed nigericin-induced NLRP3 inflammasome activation without blocking ASC oligomerization, suggesting that it may inhibit NLRP3 inflammasome activation by preventing caspase-1 processing. Our study thus indicates that EOAA inhibits NLRP3 inflammasome activation and has therapeutic potential against NLRP3-driven diseases.


2021 ◽  
Vol 5 (5) ◽  
pp. 1523-1534
Author(s):  
Johan Courjon ◽  
Océane Dufies ◽  
Alexandre Robert ◽  
Laurent Bailly ◽  
Cédric Torre ◽  
...  

Abstract Dysregulated immune response is the key factor leading to unfavorable coronavirus disease 2019 (COVID-19) outcome. Depending on the pathogen-associated molecular pattern, the NLRP3 inflammasome can play a crucial role during innate immunity activation. To date, studies describing the NLRP3 response during severe acute respiratory syndrome coronavirus 2 infection in patients are lacking. We prospectively monitored caspase-1 activation levels in peripheral myeloid cells from healthy donors and patients with mild to critical COVID-19. The caspase-1 activation potential in response to NLRP3 inflammasome stimulation was opposed between nonclassical monocytes and CD66b+CD16dim granulocytes in severe and critical COVID-19 patients. Unexpectedly, the CD66b+CD16dim granulocytes had decreased nigericin-triggered caspase-1 activation potential associated with an increased percentage of NLRP3 inflammasome impaired immature neutrophils and a loss of eosinophils in the blood. In patients who recovered from COVID-19, nigericin-triggered caspase-1 activation potential in CD66b+CD16dim cells was restored and the proportion of immature neutrophils was similar to control. Here, we reveal that NLRP3 inflammasome activation potential differs among myeloid cells and could be used as a biomarker of a COVID-19 patient’s evolution. This assay could be a useful tool to predict patient outcome. This trial was registered at www.clinicaltrials.gov as #NCT04385017.


2021 ◽  
Vol 49 (08) ◽  
pp. 2001-2015
Author(s):  
Guixian Zhang ◽  
Liming Tang ◽  
Hongbin Liu ◽  
Dawei Liu ◽  
Manxue Wang ◽  
...  

Chronic pancreatitis (CP) is a multifactorial, inflammatory syndrome characterized by acinar atrophy and fibrosis. Activation of NOD-like receptors family pyrin domain-containing 3 (NLRP3) inflammasome is a central mediator of multiple chronic inflammatory responses and chronic fibrosis including pancreatic fibrosis in CP. The Psidium guajavaleaf is widely used in traditional medicine for the treatment of chronic inflammation, but the anti-inflammatory effect of Psidium guajavaleaf on CP has not yet been revealed. In this study, we investigated whether the extract of total flavonoids from Psidium guajava leaves (TFPGL) plays a therapeutic mechanism on CP through NLRP3 inflammasome signaling pathway in a mouse CP model. The H&E and acid-Sirius red staining indicted that TFPGL attenuated the inflammatory cell infiltration and fibrosis significantly. The results of immunohistological staining, western blot and RT-qPCR showed that the expressions of NLRP3 and caspase-1 were significantly increased in the CP model group, while TFPGL significantly decreased the NLRP3 and caspase-1 expression at both the gene and protein levels. Moreover, ELISA assay was used to examine the levels of NLRP3 inflammasome target genes, such as caspase-1, IL-1[Formula: see text] and IL-18. We found that TFPGL treatment decreased the expression of caspase-1, IL-1[Formula: see text] and IL-18, which is critical for the NLRP3 inflammasome signaling pathway and inflammation response significantly. These results demonstrated that TFPGL attenuated pancreatic inflammation and fibrosis via preventing NLRP3 inflammasome activation and TFPGL can be used as a potential therapeutic agent for CP.


2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Bin Leng ◽  
Yingjie Zhang ◽  
Xinran Liu ◽  
Zhen Zhang ◽  
Yang Liu ◽  
...  

Long-term exposure to high glucose induces vascular endothelial inflammation that can result in cardiovascular disease. Astragaloside IV (As-IV) is widely used for anti-inflammatory treatment of cardiovascular diseases. However, its mechanism of action is still not fully understood. In this study, we investigated the effect of As-IV on high glucose-induced endothelial inflammation and explored its possible mechanisms. In vivo, As-IV (40 and 80 mg/kg/d) was orally administered to rats for 8 weeks after a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg). In vitro, human umbilical vein endothelial cells (HUVECs) were treated with high glucose (33 mM glucose) in the presence or absence of As-IV, NPS2143 (CaSR inhibitor), BAY 11-7082 (NF-κB p65 inhibitor), and INF39 (NLRP3 inhibitor), and overexpression of CaSR was induced by infection of CaSR-overexpressing lentiviral vectors to further discuss the anti-inflammatory property of As-IV. The results showed that high glucose increased the expression of interleukin-18 (IL-18), interleukin-1β (IL-1β), NLRP3, caspase-1, and ASC, as well as the protein level of TLR4, nucleus p65, and CaSR. As-IV can reverse these changes in vivo and in vitro. Meanwhile, NPS2143, BAY 11-7082, and INF39 could significantly abolish the high glucose-enhanced NLRP3, ASC, caspase-1, IL-18, and IL-1β expression in vitro. In addition, both NPS2143 and BAY 11-7082 attenuated high glucose-induced upregulation of NLRP3, ASC, caspase-1, IL-18, and IL-1β expression. In conclusion, this study suggested that As-IV could inhibit high glucose-induced NLRP3 inflammasome activation and subsequent secretion of proinflammatory cytokines via inhibiting TLR4/NF-κB signaling pathway and CaSR, which provides new insights into the anti-inflammatory activity of As-IV.


2020 ◽  
Vol 18 ◽  
pp. 205873922093492
Author(s):  
Jia Hu ◽  
Jie Wei ◽  
Cheng Zeng ◽  
Fengqi Duan ◽  
Sijun Liu ◽  
...  

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.


Pharmacology ◽  
2018 ◽  
Vol 101 (5-6) ◽  
pp. 236-245 ◽  
Author(s):  
Shiro Nakamura ◽  
Toshio Watanabe ◽  
Tetsuya Tanigawa ◽  
Sunao Shimada ◽  
Yuji Nadatani ◽  
...  

Activation of the NOD-Like Receptor Family, Pyrin Domain-Containing 3 (NLRP3) inflammasome, which consists of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and pro-caspase-1, triggers pro-caspase-1 cleavage promoting the processing of pro-interleukin (IL)-1β into mature IL-1β, which is critical for the development of non-steroidal anti-inflammatory drug (NSAID)-induced enteropathy. We investigated the effects of isoliquiritigenin, a flavonoid derived from the roots of Glycyrrhiza species, on NSAID-induced small intestinal damage and the inflammasome activation. To induce enteropathy, mice were administered indomethacin by gavage with or without isoliquiritigenin pretreatment. Some mice received an intraperitoneal injection of recombinant murine IL-1β in addition to isoliquiritigenin and indomethacin. Indomethacin induced small intestinal damage and increased protein levels of cleaved caspase-1 and mature IL-1β in the small intestine. Treatment with 7.5 and 75 mg/kg isoliquiritigenin inhibited indomethacin-induced small intestinal damage by 40 and 56%, respectively. Isoliquiritigenin also inhibited the indomethacin-induced increase in cleaved caspase-1 and mature IL-1β protein levels, whereas it did not affect the mRNA expression of NLRP3, ASC, caspase-1, and IL-1β. Protection against intestinal damage in isoliquiritigenin-treated mice was completely abolished with exogenous IL-1β. NLRP3–/– and caspase-1–/– mice exhibited resistance to intestinal damage, and isoliquiritigenin treatment failed to inhibit the damage in NLRP3–/– and caspase-1–/– mice. Isoliquiritigenin prevents NSAID-induced small intestinal damage by inhibiting NLRP3 inflammasome activation.


Blood ◽  
2013 ◽  
Vol 121 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Ming-Fang Wu ◽  
Szu-Ting Chen ◽  
An-Hang Yang ◽  
Wan-Wan Lin ◽  
Yi-Ling Lin ◽  
...  

AbstractPersistent high fever is one of the most typical clinical symptoms in dengue virus (DV)–infected patients. However, the source of endogenous pyrogen (eg, IL-1β) and the signaling cascade leading to the activation of inflammasome and caspase-1, which are essential for IL-1β and IL-18 secretion, during dengue infection have not been elucidated yet. Macrophages can be polarized into distinct phenotypes under the influence of GM-CSF or M-CSF, denoted as GM-Mφ and M-Mφ, respectively. We found that DV induced high levels of IL-1β and IL-18 from GM-Mφ (inflammatory macrophage) and caused cell death (pyroptosis), whereas M-Mφ (resting macrophage) did not produce IL-1β and IL-18 on DV infection even with lipopolysaccharide priming. This observation demonstrates the distinct responses of GM-Mφ and M-Mφ to DV infection. Moreover, up-regulation of pro-IL-1β, pro-IL-18, and NLRP3 associated with caspase-1 activation was observed in DV-infected GM-Mφ, whereas blockade of CLEC5A/MDL-1, a C-type lectin critical for dengue hemorrhagic fever and Japanese encephalitis virus infection, inhibits NLRP3 inflammasome activation and pyrotopsis in GM-Mφ. Thus, DV can activate NLRP3 inflammasome via CLEC5A, and GM-Mφ plays a more important role than M-Mφ in the pathogenesis of DV infection.


Sign in / Sign up

Export Citation Format

Share Document