Abstract 11852: Role of Lox-1 in Mitochondrial Dna Damage and NLRP3 Inflammasome Activation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Zufeng Ding ◽  
Sadip Pant ◽  
Abhishek Deshmukh ◽  
Jawahar L Mehta
Keyword(s):  
Dna Damage ◽  
Mitochondrial Dna ◽  
Nlrp3 Inflammasome ◽  
Ros Generation ◽  
Inflammasome Activation ◽  
Mtdna Damage ◽  
Mitochondrial Dna Damage ◽  
Mitochondrial Ros ◽  
Nlrp3 Inflammasome Activation

Objective: This study tested the hypothesis that mitochondrial DNA damage could trigger NLRP3 inflammasome activation during inflammation, and LOX-1 may play a critical role in this process. Methods and Results: We performed studies in cultured human THP1 macrophages exposed to ox-LDL or LPS,which are often used as inflammation stimuli in vitro . We examined and confirmed the increase in LOX-1 expression when cells were treated with ox-LDL or LPS. Parallel groups of cells were treated with LOX-1 Ab to bind LOX-1. In accordance with our previous studies in endothelial cells and smooth muscle cells, LOX-1 Ab markedly reduced ox-LDL- as well as LPS-stimulated LOX-1 expression. To assess mitochondrial ROS generation, MitoSOX™ Red mitochondrial superoxide indicator was used. Both fluorescence staining and flow cytometry analysis showed that LPS induced (more than ox-LDL) mitochondrial ROS generation. Pretreatment with LOX-1 Ab significantly attenuated mitochondrial ROS generation in response to ox-LDL or LPS. Then we observed mtDNA damage in THP1 cells exposed to ox-LDL or LPS. Importantly, pretreatment with LOX-1 Ab protected mtDNA from damage in response to both stimuli. This was also confirmed by q-PCR (mtDNA/nDNA ratio) analysis. Further, ox-LDL or LPS induced the expression of phos-NF-kB p65, caspase-1 p10 and p20, and cleaved proteins IL-1β and IL-18. Of note, NLRP3 inflammasome was activated in response to ox-LDL or LPS in a similar manner. Pretreatment of cells with LOX-1 Ab treatment blocked or significantly attenuated these inflammatory responses. Conclusions: These observations based on in vitro observations indicate that LOX-1 via ROS generation plays a key role in mtDNA damage which then leads to NLRP3 inflammasome activation during inflammation.

Abstract 96: Melatonin Prevents Atherosclerosis via Regulating NLRP3 Inflammasome: The Role of Sirt3 Signaling

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Sai Ma ◽  
Jiangwei Chen ◽  
Zhenli Luo ◽  
Yabin Wang ◽  
Feng Cao
Keyword(s):  
Protective Effect ◽  
Signaling Pathway ◽  
Nlrp3 Inflammasome ◽  
Inflammatory Factors ◽  
Ros Generation ◽  
Inflammasome Activation ◽  
Mitochondrial Ros ◽  
Nlrp3 Inflammasome Activation

Introduction: NLRP3 inflammasome mediated inflammatory factors secretion is critically involved in atherosclerosis (AS). Melatonin has anti-inflammatory properties. However, it is unknown whether melatonin is beneficial in AS. Hypothesis: Melatonin plays a beneficial role in AS by decreasing NLRP3 inflammasome activation in macrophages. Methods: AS model was induced with high fat diet in apoE -/- mice. Plaque stability was examined with historical staining. In vitro study was performed in ox-LDL treated RAW264.7 cells. NLRP3 inflammasome activation, inflammatory factors secretion, mitochondrial ROS generation, autophagy, mitophagy indexes and potential signaling pathways were investigated. Results: Historical staining results showed that melatonin treatment markedly alleviated AS plaque progression. Despite of unchanged protein expression, Sirt 3 activity was elevated in plaque tissue in melatonin treated mice. Melatonin attenuated NLRP3 inflammasome activation and inflammatory factors secretion in ox-LDL treated macrophages, while this protective effect was abolished by Sirt3-siRNA. Mitochondrial ROS (mitoROS), which was an inducer for NLRP3 inflammasome, was reduced by melatonin through the elimination of damaged mitochondria (mitophagy). Similar with Sirt3-siRNA, autophagy inhibitor 3-MA also abolished the effects of melatonin on mitoROS clearance, indicating the crucial role of autophagy and mitophagy in melatonin caused NLRP3 inactivation. Furthermore, melatonin protected against AS via Sirt3/FoxO3/Parkin signaling pathway. Conclusions: Melatonin prevented atherosclerotic progression. Melatonin reduced mitochondrial ROS through the activation of autophagy and mitophagy, thereby attenuating NLRP3 inflammasome activation in macrophages. Moreover, the protective effect of melatonin was mediated by Sirt3/FoxO3/Parkin signaling pathway. Our study provides insight into a new therapeutic target for AS.

Pharmacological Blocker of NF-κb and Mitochondrial Ros Restrict NLRP3 Inflammasome Activation and Rescue Dopaminergic Neurons in Vitro and in Vivo Parkinson’s Disease

2021 ◽  
Author(s):  
Sahabuddin Ahmed ◽  
Samir Ranjan Panda ◽  
Mohit Kwatra ◽  
Bidya Dhar Sahu ◽  
VGM Naidu
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Free Radicals ◽  
Nlrp3 Inflammasome ◽  
Nuclear Translocation ◽  
Inflammasome Activation ◽  
Mitochondrial Ros ◽  
Nlrp3 Inflammasome Activation

Abstract Several activators of NLRP3 inflammasome have been described; however, the central mechanisms of NLRP3 inflammasome activation in brain microglia, especially at the activating step through free radical generation, still require further clarification. Hence the present study aimed to investigate the role of free radicals in activating NLRP3 inflammasome driven neurodegeneration and elucidated the neuroprotective role of perillyl alcohol (PA) in vitro and in vivo models of Parkinson’s disease. Initial priming of microglial cells with lipopolysaccharide (LPS) following treatment with hydrogen peroxide (H2O2) induces NF-κB translocation to nucleus with robust generation of free radicals that act as Signal 2 in augmenting NLRP3 inflammasome assembly and its downstream targets. PA treatment suppresses nuclear translocation of NF-κB and maintains cellular redox homeostasis in microglia that limits NLRP3 inflammasome activation along with processing active caspase-1, IL-1β and IL-18. To further correlates the in vitro study with in vivo MPTP model, treatment with PA also inhibits the nuclear translocation of NF-κB and downregulates the NLRP3 inflammasome activation. PA administration upregulates various antioxidant enzymes levels and restored the level of dopamine and other neurotransmitters in the striatum of the mice brain with improved behavioural activities. Additionally, treatment with Mito-TEMPO (a mitochondrial ROS inhibitor) was also seen to inhibit NLRP3 inflammasome and rescue dopaminergic neuron loss in the mice brain. Therefore, we conclude that NLRP3 inflammasome activation requires a signal from damaged mitochondria for its activation. Further pharmacological scavenging of free radicals restricts microglia activation and simultaneously supports neuronal survival via targeting NLRP3 inflammasome pathway in Parkinson’s disease.

scholarly journals Coenzyme Q0 Inhibits NLRP3 Inflammasome Activation through Mitophagy Induction in LPS/ATP-Stimulated Macrophages

2022 ◽  
Vol 2022 ◽  
pp. 1-15
Author(s):  
You-Cheng Hseu ◽  
Yu-Fang Tseng ◽  
Sudhir Pandey ◽  
Sirjana Shrestha ◽  
Kai-Yuan Lin ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Coenzyme Q ◽  
Antioxidant Properties ◽  
Variable Number ◽  
Ros Generation ◽  
Inflammasome Activation ◽  
Raw264.7 Macrophages ◽  
Mitochondrial Ros ◽  
Nlrp3 Inflammasome Activation ◽  
Anti Inflammatory

Coenzyme Q (CoQ) analogs with a variable number of isoprenoid units have exhibited as anti-inflammatory as well as antioxidant molecules. Using novel quinone derivative CoQ0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone, zero side chain isoprenoid), we studied its molecular activities against LPS/ATP-induced inflammation and redox imbalance in murine RAW264.7 macrophages. CoQ0’s non- or subcytotoxic concentration suppressed the NLRP3 inflammasome and procaspase-1 activation, followed by downregulation of IL1β expression in LPS/ATP-stimulated RAW264.7 macrophages. Similarly, treatment of CoQ0 led to LC3-I/II accumulation and p62/SQSTM1 activation. An increase in the Beclin-1/Bcl-2 ratio and a decrease in the expression of phosphorylated PI3K/AKT, p70 S6 kinase, and mTOR showed that autophagy was activated. Besides, CoQ0 increased Parkin protein to recruit damaged mitochondria and induced mitophagy in LPS/ATP-stimulated RAW264.7 macrophages. CoQ0 inhibited LPS/ATP-stimulated ROS generation in RAW264.7 macrophages. Notably, when LPS/ATP-stimulated RAW264.7 macrophages were treated with CoQ0, Mito-TEMPO (a mitochondrial ROS inhibitor), or N-acetylcysteine (NAC, a ROS inhibitor), there was a significant reduction of LPS/ATP-stimulated NLRP3 inflammasome activation and IL1β expression. Interestingly, treatment with CoQ0 or Mito-TEMPO, but not NAC, significantly increased LPS/ATP-induced LC3-II accumulation indicating that mitophagy plays a key role in the regulation of CoQ0-inhibited NLRP3 inflammasome activation. Nrf2 knockdown significantly decreased IL1β expression in LPS/ATP-stimulated RAW264.7 macrophages suggesting that CoQ0 inhibited ROS-mediated NLRP3 inflammasome activation and IL1β expression was suppressed due to the Nrf2 activation. Hence, this study showed that CoQ0 might be a promising candidate for the therapeutics of inflammatory disorders due to its effective anti-inflammatory as well as antioxidant properties.

scholarly journals Bletilla striata Polysaccharide Promotes Diabetic Wound Healing Through Inhibition of the NLRP3 Inflammasome

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Zhao ◽  
Qibin Wang ◽  
Shan Yan ◽  
Jun Zhou ◽  
Liangyong Huang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Insulin Sensitivity ◽  
Cell Viability ◽  
Nlrp3 Inflammasome ◽  
Ros Generation ◽  
Inflammasome Activation ◽  
Bletilla Striata ◽  
Nlrp3 Inflammasome Activation ◽  
Diabetic Wound Healing

The aim of this study was to evaluate the therapeutic effects of Bletilla striata polysaccharide (BSP) on wound healing in diabetes mellitus (DM) and to explore the underlying mechanisms. DM mouse models were induced by high fat-diet feeding combined with low-dose streptozocin injection. To establish diabetic foot ulcer (DFU) models, DM mice were wounded on the dorsal surface. Subsequently, mice were treated with vehicle or BSP for 12 days and wound healing was monitored. The effects of BSP on the production of interleukin-1β (IL-1β), tumor necrosis factor-α, macrophages infiltration, angiogenesis, the activation of nucleotide-binding and oligomerization (NACHT) domain, leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome, and insulin sensitivity in wound tissues were subsequently evaluated. Separated- and cultured- bone marrow-derived macrophages (BMDMs) and cardiac microvascular endothelial cells (CMECs) were isolated from mice and used to investigate the effects of BSP on cell viability, reactive oxygen species (ROS) generation, NLRP3 inflammasome activation and insulin sensitivity in vitro following exposure to high glucose (HG). BSP administration accelerated diabetic wound healing, suppressed macrophage infiltration, promoted angiogenesis, suppressed NLRP3 inflammasome activation, decreased IL-1β secretion, and improved insulin sensitivity in wound tissues in DM mice. In vitro, co-treatment with BSP protected against HG-induced ROS generation, NLRP3 inflammasome activation, and IL-1β secretion in BMDMs, and improved cell viability and decreased ROS levels in CMECs. Moreover, in HG exposed BMDMs-CMECs cultures, BSP treatment suppressed NLRP3 inflammasome activation and IL-1β secretion in BMDMs, and improved cell viability and insulin sensitivity in CMECs. Furthermore, treatment with IL-1β almost completely suppressed the beneficial effects of BSP on the NLRP3 inflammasome, IL-1β secretion, and insulin sensitivity in HG-treated BMDMs-CMECs. BSP promotes DFU healing through inhibition of the HG-activated NLRP3 inflammasome.

Panax notoginseng saponins attenuate neuroinflammation through TXNIP-mediated NLRP3 inflammasome activation in aging rats

2020 ◽  
Vol 21 ◽  
Author(s):  
Zhiyong Zhou ◽  
Menghan He ◽  
Qingqing Zhao ◽  
Dongfan Wang ◽  
Changcheng Zhang ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Panax Notoginseng ◽  
Control Group ◽  
Inflammasome Activation ◽  
Panax Notoginseng Saponins ◽  
Aging Rats ◽  
Nlrp3 Inflammasome Activation ◽  
Bv2 Microglia ◽  
Old Rats

Introduction:: Microglia-mediated inflammatory responses play a crucial role in aging-related neurodegenerative diseases. The TXNIP/NLRP3 pathway is a key pathway leading to microglial activation. Panax notoginseng saponins (PNS) have been widely used for the treatment of stroke in China. Objective:: This study evaluates the anti-neuroinflammatory effect of PNS and investigates the mechanism via TXNIPmediated NLRP3 inflammasome activation in aging rats. Materials and Methods:: Eighteen-month-old Sprague-Dawley rats were randomly divided into the aging control group and PNS treated groups (n=15 each group). For PNS-treated groups, rats were administrated food with PNS at the doses of 10 mg/kg and 30 mg/kg for consecutive 6 months until they were 24-month old. Rats from the aging control group were given the same food without PNS. Two-month-old rats were purchased and given the same food until 6-month old as the adult control group (n = 15). Then, the cortex and hippocampus were rapidly harvested and deposited. H&E staining was used to assess histo-morphological changes. Western blotting was carried out to detect the protein expression. Immunofluorescence was employed to measure the co-localization of NLRP3, TXNIP and Iba-1. In vitro model was established by LPS+ATP coincubation in the BV2 microglia cell line. Results:: Aging rats exhibited increased activation of microglia, accompanied by a high level of IL-1β expression. Meanwhile, aging rats showed enhanced protein expression of TXNIP and NLRP3 related molecules, which co-localized with microglia. PNS treatment effectively reduced the number of degenerated neurons and reversed the activation of the TXNIP/NLRP3 inflammatory pathway. In vitro results showed that PNS up to 100 μg / ml had no significant toxicity on BV2 microglia. Discussion:: PNS (25, 50 μg/ml) effectively reduced the inflammatory response induced by LPS and ATP co-stimulation, thus inhibiting the expression of TXNIP/NLRP3 pathway-related proteins. Conclusion:: PNS treatment improved aging-related neuronal damage through inhibiting TXNIP mediated NLRP3 inflammasome activation, which provided a potential target for the treatment of inflammatory-related neurodegenerative diseases.

scholarly journals Role of ASM/Cer/TXNIP signaling module in the NLRP3 inflammasome activation

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jianjun Jiang ◽  
Yining Shi ◽  
Jiyu Cao ◽  
Youjin Lu ◽  
Gengyun Sun ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Nlrp3 Inflammasome ◽  
Mrna Level ◽  
Scavenger Receptor ◽  
Nuclear Factor Κb ◽  
Inflammasome Activation ◽  
Mrna Levels ◽  
Irreversible Inhibitor ◽  
Nlrp3 Inflammasome Activation

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.

Kaempferol Alleviates Corneal Transplantation Rejection by Inhibiting NLRP3 Inflammasome Activation and Macrophage M1 Polarization via Promoting Autophagy

2021 ◽  
Author(s):  
Huiwen Tian ◽  
Shumei Lin ◽  
Jing Wu ◽  
Ming Ma ◽  
Jian Yu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Macrophage Polarization ◽  
Corneal Transplantation ◽  
Inflammasome Activation ◽  
M1 Polarization ◽  
Nlrp3 Inflammasome Activation ◽  
M1 Macrophage ◽  
Transplantation Rejection

Abstract Corneal transplantation rejection remains a major threat to the success rate in high-risk patients. Given the many side effects presented by traditional immunosuppressants, there is an urgency to clarify the mechanism of corneal transplantation rejection and to identify new therapeutic targets. Kaempferol is a natural flavonoid that has been proven in various studies to possess anti-inflammatory, antioxidant, anticancer, and neuroprotective properties. However, the relationship between kaempferol and corneal transplantation remains largely unexplored. To address this, both in vivo and in vitro, we established a model of corneal allograft transplantation in Wistar rats and an LPS-induced inflammatory model in THP-1 derived human macrophages. In the transplantation experiments, we observed an enhancement in the NLRP3 / IL-1 β axis and in M1 macrophage polarization post-operation. In groups to which kaempferol intraperitoneal injections were administered, this response was effectively reduced. However, the effect of kaempferol was reversed after the application of autophagy inhibitors. Similarly, in the inflammatory model, we found that different concentrations of kaempferol can reduce the LPS-induced M1 polarization and NLRP3 inflammasome activation. Moreover, we confirmed that kaempferol induced autophagy and that autophagy inhibitors reversed the effect in macrophages. In conclusion, we found that kaempferol can inhibit the activation of the NLRP3 inflammasomes by inducing autophagy, thus inhibiting macrophage polarization, and ultimately alleviating corneal transplantation rejection. Thus, our study suggests that kaempferol could be used as a potential therapeutic agent in the treatment of allograft rejection.

ASC deglutathionylation is a checkpoint for NLRP3 inflammasome activation

2021 ◽  
Vol 218 (9) ◽  
Author(s):  
Shuhang Li ◽  
Linlin Wang ◽  
Zhihao Xu ◽  
Yuanyuan Huang ◽  
Rufeng Xue ◽  
...  
Keyword(s):  
Metabolic Control ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Mitochondrial Ros ◽  
Nlrp3 Inflammasome Activation ◽  
Multiple Molecules ◽  
Excessive Activation

Activation of NLRP3 inflammasome is precisely controlled to avoid excessive activation. Although multiple molecules regulating NLRP3 inflammasome activation have been revealed, the checkpoints governing NLRP3 inflammasome activation remain elusive. Here, we show that activation of NLRP3 inflammasome is governed by GSTO1-promoted ASC deglutathionylation in macrophages. Glutathionylation of ASC inhibits ASC oligomerization and thus represses activation of NLRP3 inflammasome in macrophages, unless GSTO1 binds ASC and deglutathionylates ASC at ER, under control of mitochondrial ROS and triacylglyceride synthesis. In macrophages expressing ASCC171A, a mutant ASC without glutathionylation site, activation of NLRP3 inflammasome is GSTO1 independent, ROS independent, and signal 2 less dependent. Moreover, AscC171A mice exhibit NLRP3-dependent hyperinflammation in vivo. Our results demonstrate that glutathionylation of ASC represses NLRP3 inflammasome activation, and GSTO1-promoted ASC deglutathionylation at ER, under metabolic control, is a checkpoint for activating NLRP3 inflammasome.

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