scholarly journals The Roles of Endoplasmic Reticulum in NLRP3 Inflammasome Activation

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1219 ◽  
Author(s):  
Yang Zhou ◽  
Zhizi Tong ◽  
Songhong Jiang ◽  
Wenyan Zheng ◽  
Jianjun Zhao ◽  
...  

The NLRP3 (nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3) inflammasome senses pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), and activates caspase-1, which provokes release of proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-18 as well as pyroptosis to engage in innate immune defense. The endoplasmic reticulum (ER) is a large and dynamic endomembrane compartment, critical to cellular function of organelle networks. Recent studies have unveiled the pivotal roles of the ER in NLRP3 inflammasome activation. ER–mitochondria contact sites provide a location for NLRP3 activation, its association with ligands released from or residing in mitochondria, and rapid Ca2+ mobilization from ER stores to mitochondria. ER-stress signaling plays a critical role in NLRP3 inflammasome activation. Lipid perturbation and cholesterol trafficking to the ER activate the NLRP3 inflammasome. These findings emphasize the importance of the ER in initiation and regulation of the NLRP3 inflammasome.

2018 ◽  
Author(s):  
Yong Yang ◽  
Jianxin Li ◽  
Ting-Li Han ◽  
Xiaobo Zhou ◽  
Hongbo Qi ◽  
...  

AbstractPreeclampsia (PE) development is often associated with placental immune and inflammatory dysregulation, as well as endoplasmic reticulum (ER) stress. However, the mechanisms linking ER stress and inflammatory dysregulation to PE have not been clarified. It has been reported that thioredoxin-interacting protein (TXNIP), which can bind with and activate the NLR family pyrin domain containing 3 (NLRP3) inflammasome, plays a critical role in immune regulation. Recent experimental evidence suggests that activated NLRP3 inflammasomes can activate interleukin-1β (IL-1β) production in the placenta of patients with PE. The objective of the current study was to explore if TXNIP plays a critical signaling role linking ER stress with NLRP3 inflammasome activation in PE. We hypothesised that ER stress would induce TXNIP production, which would bind with NLRP3 inflammasomes to activate IL-1β production. HTR8/SVneo cells were subjected to six hours hypoxia followed by six hours reoxygenation (H/R). These cells showed a higher protein level of NLRP3 and IL-1β, as well as a higher enzymatic activity of caspase-1, indicating enhanced inflammatory dysregulation and ER stress. Cells transfected with TXNIP siRNA showed reduced NLRP3 inflammasome activation. Cells treated with 4-phenylbutyric acid, an inhibitor of ER stress, showed a similar result. In addition, the outgrowth of explant with TXNIP lentivirus in H/R or Tunicamycin (inducers of ER stress) was also measured to verify our hypothesis. These findings demonstrated that TXNIP could influence inflammatory dysregulation by mediating ER stress and NLRP3 inflammasome activation in PE. This novel mechanism may further explain the inflammation observed at the maternal-fetal interface, which leads to placental dysfunction in a patient with PE.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Judit Erdei ◽  
Andrea Tóth ◽  
Enikő Balogh ◽  
Benard Bogonko Nyakundi ◽  
Emese Bányai ◽  
...  

Hemolytic or hemorrhagic episodes are often associated with inflammation even when infectious agents are absent suggesting that red blood cells (RBCs) release damage-associated molecular patterns (DAMPs). DAMPs activate immune and nonimmune cells through pattern recognition receptors. Heme, released from RBCs, is a DAMP and induces IL-1βproduction through the activation of the nucleotide-binding domain and leucine-rich repeat-containing family and pyrin domain containing 3 (NLRP3) in macrophages; however, other cellular targets of heme-mediated inflammasome activation were not investigated. Because of their location, endothelial cells can be largely exposed to RBC-derived DAMPs; therefore, we investigated whether heme and other hemoglobin- (Hb-) derived species induce NLRP3 inflammasome activation in these cells. We found that heme upregulated NLRP3 expression and induced active IL-1βproduction in human umbilical vein endothelial cells (HUVECs). LPS priming largely amplified the heme-mediated production of IL-1β. Heme administration into C57BL/6 mice induced caspase-1 activation and cleavage of IL-1βwhich was not observed in NLRP3−/−mice. Unfettered production of reactive oxygen species played a critical role in heme-mediated NLRP3 activation. Activation of NLRP3 by heme required structural integrity of the heme molecule, as neither protoporphyrin IX nor iron-induced IL-1βproduction. Neither naive nor oxidized forms of Hb were able to induce IL-1βproduction in HUVECs. Our results identified endothelial cells as a target of heme-mediated NLRP3 activation that can contribute to the inflammation triggered by sterile hemolysis. Thus, understanding the characteristics and cellular counterparts of RBC-derived DAMPs might allow us to identify new therapeutic targets for hemolytic diseases.


Reproduction ◽  
2021 ◽  
Vol 162 (6) ◽  
pp. 449-460
Author(s):  
Zixi Chen ◽  
Yali Shan ◽  
Xingji You ◽  
Hang Gu ◽  
Chen Xu ◽  
...  

The nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome plays a critical role in various inflammatory diseases. We sought to investigate the role of NLRP3 inflammasome in uterine activation for labor at term and preterm. We found that NLRP3 inflammasome was activated in the myometrium tissues obtained from the pregnant women undergoing labor at term (TL) compared with those not undergoing labor (TNL) at term. NLRP3 inflammasome was also activated in amnion and chorion-deciduas in TL and preterm labor (PTL) groups. In the mouse model, uterine NLRP3 inflammasome and nuclear factor kappaB (NF-κB) were activated toward term and during labor. Treatment of pregnant mice with lipopolysaccharide (LPS) and RU38486 induced preterm birth (PTB) and also promoted uterine NLRP3 inflammasome and NF-κB activation. Treatment of pregnant mice with NLRP3 inflammasome inhibitor BAY11-7082 and MCC950 delayed the onset of labor and suppressed NLRP3 inflammasome and NF-κB activation in uterus. MCC950 postponed labor onset of the mice with LPS and RU38486 treatment and inhibited NLRP3 inflammasome activation in uterus. Our data provide the evidence that NLRP3 inflammasome is involved in uterine activation for labor onset in term and PTB in humans and mouse model.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mikel D. Haggadone ◽  
Jamison J. Grailer ◽  
Fatemeh Fattahi ◽  
Firas S. Zetoune ◽  
Peter A. Ward

C5a is an inflammatory mediator generated by complement activation that positively regulates various arms of immune defense, including Toll-like receptor 4 (TLR4) signaling. The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is activated by pathogen products and cellular/tissue damage products and is a major contributor of IL-1β. In this study, we investigate whether C5a modulates lipopolysaccharide- (LPS-) induced NLRP3 inflammasome activation in myeloid cells. Appearance of plasma IL-1βduring endotoxemia was reduced inC5aR1-/-mice when compared to wild-type mice. In vitro, C5a significantly enhanced LPS-induced production of IL-1βin bone marrow Ly6C-high inflammatory monocytes, accompanied by augmented intracellular pro-IL-1βexpression. This effect was abolished during p38 blockade by SB 203580 and in the absence of C5aR1. Conversely, C5a suppressed LPS-induced macrophage production of IL-1β, which was accompanied by attenuated levels of pro-IL-1β, NLRP3, and caspase-1 expression. C5a’s suppressive effects were negated during phosphoinositide 3-kinase (PI3K) inhibition by wortmannin but were largely preserved in the absence of C5aR1. Thus, C5a bidirectionally amplifies TLR4-mediated NLRP3 inflammasome activation in monocytes while suppressing this pathway in macrophages. However, as C5aR1 deficiency attenuates the IL-1βresponse to LPS challenge in vivo, our results suggest overall that C5a augments physiologic inflammasome responses.


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.


2018 ◽  
Vol 315 (6) ◽  
pp. G909-G920 ◽  
Author(s):  
Lanju Wang ◽  
Yaohui Wang ◽  
Zhenfeng Wang ◽  
Yu Qi ◽  
Beibei Zong ◽  
...  

Growth differentiation factor 11 (GDF11) has an anti-inflammatory effect in the mouse model of atherosclerosis and Alzheimer's disease, but how GDF11 regulates intestinal inflammation during ulcerative colitis (UC) is poorly defined. The Nod-like receptor family pyrin domain-1 containing 3 (NLRP3) inflammasome is closely associated with intestinal inflammation because of its ability to increase IL-1β secretion. Our aim is to determine whether GDF11 has an effect on attenuating experimental colitis in mice. In this study, using a dextran sodium sulfate (DSS)-induced acute colitis mouse model, we reported that GDF11 treatment attenuated loss of body weight, the severity of the disease activity index, shortening of the colon, and histological changes in the colon. GDF11 remarkably suppressed IL-1β secretion and NLRP3 inflammasome activation in colon samples and RAW 264.7 cells, such as the levels of NLRP3 and activated caspase-1. Furthermore, we found that GDF11 inhibited NLRP3 inflammasome activation by downregulating the Toll-like receptor 4/NF-κB p65 pathway and reactive oxygen species production via the typical Smad2/3 pathway. Thus, our research shows that GDF11 alleviates DSS-induced colitis by inhibiting NLRP3 inflammasome activation, providing some basis for its potential use in the treatment of UC. NEW & NOTEWORTHY Here, we identify a new role for growth differentiation factor 11 (GDF11), which ameliorates dextran sodium sulfate-induced acute colitis. Meanwhile, we discover a new phenomenon of GDF11 inhibiting IL-1β secretion and Nod-like receptor family pyrin domain-1 containing 3 (NLRP3) inflammasome activation. These findings reveal that GDF11 is a new potential candidate for the treatment of ulcerative colitis patients with a hyperactive NLRP3 inflammasome.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xin Zhang ◽  
Siting Hong ◽  
Shuhan Qi ◽  
Wenxiu Liu ◽  
Xiaohui Zhang ◽  
...  

Increasing evidence suggests that the NLRP3 (nucleotide oligomerization domain-like receptor family, pyrin domain containing 3) inflammasome participates in cardiovascular diseases. However, its role and activation mechanism during hypertension remains unclear. In this study, we tested the role and mechanism of calcium-sensing receptor (CaSR) in NLRP3 inflammasome activation during hypertension. We observed that the expressions of CaSR and NLRP3 were increased in spontaneous hypertensive rats (SHRs) along with aortic fibrosis. In vascular smooth muscle cells (VSMCs), the activation of NLRP3 inflammasome associated with CaSR and collagen synthesis was induced by angiotensin II (Ang II). Furthermore, inhibition of CaSR and NLRP3 inflammasome attenuated proinflammatory cytokine release, suggesting that CaSR-mediated activation of the NLRP3 inflammasome may be a therapeutic target in aortic dysfunction and vascular inflammatory lesions.


2020 ◽  
Vol 11 ◽  
Author(s):  
Ziwei Xu ◽  
Zi-mo Chen ◽  
Xiaoyan Wu ◽  
Linjie Zhang ◽  
Ying Cao ◽  
...  

The NLRP3 inflammasome is a core component of innate immunity, and dysregulation of NLRP3 inflammasome involves developing autoimmune, metabolic, and neurodegenerative diseases. Potassium efflux has been reported to be essential for NLRP3 inflammasome activation by structurally diverse pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs). Thus, the molecular mechanisms underlying potassium efflux to activate NLRP3 inflammasome are under extensive investigation. Here, we review current knowledge about the distinction channels or pore-forming proteins underlying potassium efflux for NLRP3 inflammasome activation with canonical/non-canonical signaling or following caspase-8 induced pyroptosis. Ion channels and pore-forming proteins, including P2X7 receptor, Gasdermin D, pannexin-1, and K2P channels involved present viable therapeutic targets for NLRP3 inflammasome related diseases.


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