Paeonol reduces IL-β production by inhibiting the activation of nucleotide oligomerization domain-like receptor protein-3 inflammasome and nuclear factor-κB in macrophages

2021 ◽  
pp. 1-9
Author(s):  
Gang Chen ◽  
Tingwang Guo ◽  
Lin Yang

Interleukin-1β, a key cytokine in gouty inflammation, is precisely regulated by the NLRP3 inflammasome and NF-κB. Our previous study demonstrated that paeonol suppressed IL-1β production in rats with monosodium urate (MSU)-induced arthritis. Whether NLRP3 inflammasome or NF-κB is responsible for the anti-inflammatory effect of paeonol remains unclear. In this study, J774A.1 cells induced by lipopolysaccharide (LPS) plus MSU, was used to investigate the effect of paeonol on NLRP3 inflammasome activation, and J774A.1 cells induced by LPS alone were used to investigate the effect of paeonol on NF-κB activation. In J774A.1 cells induced by LPS plus MSU, paeonol decreased the levels of IL-1β and caspase-1 and reduced the MSU-induced interaction of pro-caspase-1 and apoptosis-associated speck-like protein containing caspase recruitment domain (ASC), but did not affect the levels of pro-IL-1β and pro-caspase-1. In J774A.1 cells induced by LPS alone, paeonol reduced the levels of IL-1β, NLRP3, p-IKK, p-IκBα, and p-p65, but did not affect ASC levels. Paeonol also promoted the content of IκBα and retained more p65 in the cytoplasm. Furthermore, paeonol reduced the DNA-binding activity of p65 and lowered the levels of p-JNK, p-ERK, and p-p38. These results suggest that paeonol inhibits IL-1β production by inhibiting the activation of NLRP3 inflammasome, NF-κB, and MAPK signaling pathways.

2020 ◽  
Author(s):  
Yuan Yuan ◽  
Chenxu Wang ◽  
Beibei Dong ◽  
Keliang Xie ◽  
Yonghao Yu

Abstract Background Although remifentanil provides perfect analgesia during operations, postoperative remifentanil-induced hyperalgesia (RIH) might be a challenge to anaesthetists. Increasingly, the NOD-like receptor protein 3 (NLRP3) signalling pathway are being implicated in the initiation and maintenance of these conditions. In the present work, we examined the hypothesis that NLRP3 inflammasome activation contributes to RIH via regulation of NMDA receptor NR1 subunit phosphorylation and glutamate transporter-1 (GLT-1) by interleukin-1β (IL-1β). Methods We first tested the changes in thermal and mechanical hyperalgesia at baseline (24 h before remifentanil infusion) and 2 h, 6 h, 24 h, and 48 h after remifentanil infusion in a rat model of incisional pain. Then, the expression of IL-1β and GLT-1 and phosphorylation of NMDA receptor NR1 subunits (Phospho-NR1) in the L4–L6 spinal cord segments were measured. Furthermore, we investigated the effects of IL-1ra, a selective IL-1β inhibitor, on behavioural tests of RIH and on the expression of GLT-1 and Phospho-NR1. In addition, we measured the expression of TLR4, P2X7R, NLRP3 and caspase-1, which are indicators of NLRP3 inflammasome activation. Finally, we investigated the effects of (+)-naloxone (a TLR4 inhibitor), A438079 (a P2X7R inhibitor) and ac-YVADcmk (a caspase-1 inhibitor), which are all selective NLRP3 inflammasome inhibitors, on behavioural tests of RIH and on the expression of IL-1β, GLT-1 and Phospho-NR1. Results The initiation and maintenance of RIH was mediated by a previously unidentified mechanism--namely, remifentanil-induced spinal NLRP3 inflammasome activation and the associated release of IL-1β. Remifentanil induced significant postoperative hyperalgesia, as indicated by behavioural tests, which were markedly improved by pretreatment with IL-1ra and NLRP3 inflammasome inhibitors. Moreover, remifentanil infusion decreased the expression of GLT-1 and increased Phospho-NR1 in the spinal cord, which were reversed by pretreatment with IL-1ra and NLRP3 inflammasome inhibitors. More importantly, remifentanil infusion increased IL-1β expression and activated NLRP3 inflammasomes, which were significantly attenuated by NLRP3 inflammasome inhibitors. Conclusion The above results suggest that NLRP3 inflammasome activation contributes to RIH via regulation of Phospho-NR1 and GLT-1 by IL-1β. Inhibition of NLRP3 inflammasome activation or IL-1β may be an effective and novel option for the treatment of RIH.


2020 ◽  
Author(s):  
Jianjun Jiang ◽  
Jin Yang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
...  

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.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Lulu Shen ◽  
Swapnil V Shewale ◽  
Chia-Chi Chung ◽  
Elena Boudyguina ◽  
John S Parks ◽  
...  

Progression of atherosclerosis leads to progressive macrophage autophagy deficiency, which enhances inflammasome activation and atherosclerosis. We previously showed that dietary enrichment with n-3 and n-6 polyunsaturated fatty acids (PUFAs) derived from botanical oils (Echium oil (EO) containing 18:4 n-3 and borage oil (BO) containing 18:3 n-6), reduced atherosclerosis similar to that observed with fish oil (FO) consumption, compared to the saturated/monounsaturated-enriched botanical palm oil (PO). We hypothesized that dietary PUFAs enhance autophagy, which in turn, dampens macrophage NLRP3 (Nucleotide-binding oligomerization domain leucine-rich repeat containing receptor protein 3) inflammasome activation, reducing macrophage inflammation and atherosclerosis. To test the hypothesis, we fed female low density lipoprotein receptor (LDLr) knockout mice diets containing 10% (calories) PO and 0.2% cholesterol, supplemented with an additional 10% of calories as PO, EO, BO or FO for 10-16 weeks before measurement of atherosclerosis, autophagy and inflammasome activation. Compared to their PO-fed counterparts, mice fed PUFAs enriched diets (EO, BO or FO) had increased LC3-II expression in peritoneal macrophage, aorta and liver, suggesting autophagic activation. Consistent with enhanced autophagy, plasma reactive oxygen species (ROS) were significantly lower in PUFA diet-fed mice, relative to PO-fed animals. Since ROS activates, but autophagy attenuates, NLRP3 inflammasome activation, we examined whether dietary PUFAs attenuate NLRP3 inflammasome activation in mice. We found that dietary PUFAs markedly inhibited inflammasome activation, shown by: 1) less IL-1β secretion from peritoneal macrophages after ATP, oxidized LDL, or palmitate-induced NLRP3 inflammasome activation, 2) less IL-1β secretion from liver explants in response to lipopolysaccharide (LPS), and 3) deceased caspase-1 cleavage in peritoneal macrophages and liver and attenuated caspase-1 activity in blood monocytes. In conclusion, our data suggest that dietary n-3 and n-6 PUFAs are equally effective in reducing atherosclerosis, in part, by activation of macrophage autophagy and attenuation of NLRP3 inflammasome activation.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jianjun Jiang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
Gengyun Sun ◽  
...  

Abstract Background This study aimed to explore the effects of ceramide (Cer) on NLRP3 inflammasome activation and their underlying mechanisms. Methods Lipopolysaccharide (LPS)/adenosine triphosphate (ATP)-induced NLRP3 inflammasome activation in J774A.1 cells and THP-1 macrophages was used as an in vitro model of inflammation. 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 measured by ELISA. ASM assay kit and immunofluorescence were used to detect ASM activity and Cer content. Results Imipramine, a well-known inhibitor of ASM, significantly inhibited LPS/ATP-induced activity of ASM and the consequent accumulation of Cer. Additionally, imipramine suppressed the LPS/ATP-induced expression of thioredoxin interacting protein (TXNIP), NLRP3, caspase-1, IL-1β, and IL-18 at the protein and mRNA level. Interestingly verapamil, a TXNIP inhibitor, suppressed LPS/ATP-induced activation of TXNIP/NLRP3 inflammasome but did not affect LPS/ATP-induced ASM activation and Cer formation. TXNIP siRNA and verapamil inhibited C2-Cer-induced upregulation of TXNIP and activation of the NLRP3 inflammasome. In addition, the pretreatment of cells with sulfo-N-succinimidyl oleate (SSO), an irreversible inhibitor of the scavenger receptor CD36, blocked Cer-induced upregulation of nuclear factor-κB (NF-κB) activity, TXNIP expression, and NLRP3 inflammasome activation. Inhibition of NF-κB activation by SN50 prevented Cer-induced upregulation of TXNIP and activation of the NLRP3 inflammasome but did not affect CD36 expression. Conclusion This study demonstrated that the ASM/Cer/TXNIP signaling pathway is involved in NLRP3 inflammasome activation. The results documented that the CD36-dependent NF-κB-TXNIP signaling pathway plays an essential role in the Cer-induced activation of NLRP3 inflammasomes in macrophages.


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.


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