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 ◽  
...  

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.

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

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.


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.


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.


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.


2018 ◽  
Author(s):  
Francesca La Rosa ◽  
Marina Saresella ◽  
Ivana Marventano ◽  
Federica Piancone ◽  
Enrico Ripamonti ◽  
...  

AbstractAlzheimer’s disease (AD) is associated with amyloid-beta (Aβ) deposition and neuroinflammation, possibly driven by activation of the NLRP3 inflammasome. Nucleoside reverse transcriptase inhibitors (NRTI) hamper the assembly of the NLRP3 inflammasome; we analyzed whether stavudine (D4T), a prototypical NRTI, modulates Aβ-mediated inflammasome activation; because neuroinflammation impairs Aβ clearance by phagocytes, phagocytosis and autophagy were examined as well. THP-1-derived macrophages were stimulated in vitro with Aβ42 alone or after LPS priming with/without D4T. NLRP3 and TREM2 expression was analyzed by RT-PCR, phagocytosis and ASC-Speck by AmnisFlowSight, NLRP3-produced cytokines by ELISA, authophagy by P-ELISA evaluation of P-ERK and P-AKT. Results showed that IL1β, IL18 and caspase-1 were increased whereas Aβ-phagocytosis and TREM2 were reduced in LPS+Aβ42-stimulated cells. D4T reduced NLRP3 assembly as well as IL18 and caspase-1 production, but not IL1β, phagocytosis, and TREM2. P-AKT expression was augmented and P-ERK was reduced by D4T, suggesting a stimulatory effect on autophagy. D4T reduces NLRP3 inflammasome-associated inflammation, possibly restoring autophagy, in an in vitro model of AD; it will be interesting to verify its possibly beneficial effects in the clinical scenario.


Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6238
Author(s):  
Paromita Sarbadhikary ◽  
Blassan P. George ◽  
Heidi Abrahamse

The pyrin domain-containing multiprotein complex NLRP3 inflammasome, consisting of the NLRP3 protein, ASC adaptor, and procaspase-1, plays a vital role in the pathophysiology of several inflammatory disorders, including neurological and metabolic disorders, chronic inflammatory diseases, and cancer. Several phytochemicals act as promising anti-inflammatory agents and are usually regarded to have potential applications as complementary or alternative therapeutic agents against chronic inflammatory disorders. Various in vitro and in vivo studies have reported the anti-inflammatory role of berberine (BRB), an organic heteropentacyclic phytochemical and natural isoquinoline, in inhibiting NLRP3 inflammasome-dependent inflammation against many disorders. This review summarizes the mechanism and regulation of NLRP3 inflammasome activation and its involvement in inflammatory diseases, and discusses the current scientific evidence on the repressive role of BRB on NLRP3 inflammasome pathways along with the possible mechanism(s) and their potential in counteracting various inflammatory diseases.


Nanoscale ◽  
2018 ◽  
Vol 10 (19) ◽  
pp. 9141-9152 ◽  
Author(s):  
Xuyao Zhang ◽  
Jingyun Luan ◽  
Wei Chen ◽  
Jiajun Fan ◽  
Yanyang Nan ◽  
...  

Novel insights into mesoporous silica nanoparticle (MSN)-induced hepatotoxicity and the underlying mechanism, facilitating an increase of the biosafety of MSNs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenyun Zeng ◽  
Danbin Wu ◽  
Yingxin Sun ◽  
Yanrong Suo ◽  
Qun Yu ◽  
...  

AbstractNLRP3 inflammasome is a vital player in macrophages pyroptosis, which is a type of proinflammatory cell-death and takes part in the pathogenesis of atherosclerosis. In this study, we used apoE−/− mice and ox-LDL induced THP-1 derived macrophages to explore the mechanisms of MCC950, a selective NLRP3 inhibitor in treating atherosclerosis. For the in vivo study, MCC950 was intraperitoneal injected to 8-week-old apoE−/− mice fed with high-fat diet for 12 weeks. For the in vitro study, THP-1 derived macrophages were treated with ox-LDL and MCC950 for 48 h. MCC950 administration reduced plaque areas and macrophages contents, but did not improve the serum lipid profiles in aortic root of apoE−/− mice. MCC950 inhibited the activation of NLRP3/ASC/Caspase-1/GSDMD-N axis, and alleviated macrophages pyroptosis and the production of IL-1β and IL-18 both in aorta and in cell lysates. However, MCC950 did not affect the expression of TLR4 or the mRNA levels of NLRP3 inflammasome and its downstream proteins, suggesting that MCC950 had no effects on the priming of NLRP3 inflammasome activation in macrophages. The anti-atherosclerotic mechanisms of MCC950 on attenuating macrophages inflammation and pyroptosis involved in inhibiting the assembly and activation of NLRP3 inflammasome, rather than interrupting its priming.


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.


2021 ◽  
Vol 11 ◽  
Author(s):  
Yufei Luo ◽  
Bojun Xiong ◽  
Haiping Liu ◽  
Zehong Chen ◽  
Huihui Huang ◽  
...  

Koumine (KM), one of the primary constituents of Gelsemium elegans, has been used for the treatment of inflammatory diseases such as rheumatoid arthritis, but whether KM impacts the activation of the NOD-like receptor protein 3 (NLRP3) inflammasome remains unknown. This study aimed to explore the inhibitory effect of KM on NLRP3 inflammasome activation and the underlying mechanisms both in vitro using macrophages stimulated with LPS plus ATP, nigericin or monosodium urate (MSU) crystals and in vivo using an MSU-induced peritonitis model. We found that KM dose-dependently inhibited IL-1β secretion in macrophages after NLRP3 inflammasome activators stimulation. Furthermore, KM treatment efficiently attenuated the infiltration of neutrophils and suppressed IL-1β production in mice with MSU-induced peritonitis. These results indicated that KM inhibited NLRP3 inflammasome activation, and consistent with this finding, KM effectively inhibited caspase-1 activation, mature IL-1β secretion, NLRP3 formation and pro-IL-1β expression in LPS-primed macrophages treated with ATP, nigericin or MSU. The mechanistic study showed that, KM exerted a potent inhibitory effect on the NLRP3 priming step, which decreased the phosphorylation of IκBα and p65, the nuclear localization of p65, and the secretion of TNF-α and IL-6. Moreover, the assembly of NLRP3 was also interrupted by KM. KM blocked apoptosis-associated speck-like protein containing a CARD (ASC) speck formation and its oligomerization and hampered the NLRP3-ASC interaction. This suppression was attributed to the ability of KM to inhibit the production of reactive oxygen species (ROS). In support of this finding, the inhibitory effect of KM on ROS production was completely counteracted by H2O2, an ROS promoter. Our results provide the first indication that KM exerts an inhibitory effect on NLRP3 inflammasome activation associated with blocking the ROS/NF-κB/NLRP3 signal axis. KM might have potential clinical application in the treatment of NLRP3 inflammasome-related diseases.


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