Platelet-activating factor (PAF) mediates NLRP3-NEK7 inflammasome induction independently of PAFR

The role of lipids in inflammasome activation remains underappreciated. The phospholipid, platelet-activating factor (PAF), exerts multiple physiological functions by binding to a G protein–coupled seven-transmembrane receptor (PAFR). PAF is associated with a number of inflammatory disorders, yet the molecular mechanism underlying its proinflammatory function remains to be fully elucidated. We show that multiple PAF isoforms and PAF-like lipids can activate the inflammasome, resulting in IL-1β and IL-18 maturation. This is dependent on NLRP3, ASC, caspase-1, and NEK7, but not on NLRC4, NLRP1, NLRP6, AIM2, caspase-11, or GSDMD. Inflammasome activation by PAF also requires potassium efflux and calcium influx but not lysosomal cathepsin or mitochondrial reactive oxygen species. PAF exacerbates peritonitis partly through inflammasome activation, but PAFR is dispensable for PAF-induced inflammasome activation in vivo or in vitro. These findings reveal that PAF represents a damage-associated signal that activates the canonical inflammasome independently of PAFR and provides an explanation for the ineffectiveness of PAFR antagonist in blocking PAF-mediated inflammation in the clinic.

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Attenuating Effect of Chlorella Extract on NLRP3 Inflammasome Activation by Mitochondrial Reactive Oxygen Species

Frontiers in Nutrition ◽

10.3389/fnut.2021.763492 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yuya Nakashima ◽

Kazuhito Gotoh ◽

Soichi Mizuguchi ◽

Daiki Setoyama ◽

Yurie Takata ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Nlrp3 Inflammasome ◽

Reactive Oxygen ◽

Food Supplement ◽

Inflammasome Activation ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species ◽

Nlrp3 Inflammasome Activation

The NOD-like receptor family, pyrin domain-containing protein 3 (NLRP3) inflammasome has been linked to the pathogenesis of a wide variety of human diseases. Although many drugs and inhibitors have been developed to treat NLRP3-associated diseases, only limited clinical data support their efficacy and safety. Chlorella, a unicellular green alga that is widely and safely used as a food supplement, contains various antioxidants. In this study, we obtained a fat-soluble extract from Chlorella (CE) and demonstrated that it reduced NLRP3 inflammasome activation by inhibiting mitochondrial reactive oxygen species and caspase-1 activation. In addition, CE supplementation attenuated lipopolysaccharide-induced interleukin 1β transcription through activation of hypoxia-inducible factor 1α in vitro and in vivo. As Chlorella is a safe and useful food supplement, it may be a practical pharmacological approach for treating NLRP3-driven diseases.

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A Review on Melatonin’s Effects in Cancer: Potential Mechanisms

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520617666171121120223 ◽

2018 ◽

Vol 18 (7) ◽

pp. 985-992 ◽

Cited By ~ 3

Author(s):

Aysegul Hanikoglu ◽

Ertan Kucuksayan ◽

Rana Cagla Akduman ◽

Tomris Ozben

Keyword(s):

Systematic Review ◽

Antioxidant Activity ◽

Membrane Receptors ◽

Cancer Development ◽

Secretory Product ◽

Prevention And Treatment ◽

G Protein Coupled

This systematic review aims to elucidate the role of melatonin (N-acetyl-5-metoxy-tryptamine) (MLT) in the prevention and treatment of cancer. MLT is a pineal gland secretory product, an evolutionarily highly conserved molecule; it is also an antioxidant and an impressive protector of mitochondrial bioenergetic activity. MLT is characterized by an ample range of activities, modulating the physiology and molecular biology of the cell. Its physiological functions relate principally to the interaction of G Protein-Coupled MT1 and MT2 trans-membrane receptors (GPCRs), a family of guanidine triphosphate binding proteins. MLT has been demonstrated to suppress the growth of various tumours both, in vivo and in vitro. In this review, we analyze in depth, the antioxidant activity of melatonin, aiming to illustrate the cancer treatment potential of the molecule, by limiting or reversing the changes occurring during cancer development and growth.

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Mitochondrion-Dependent Cell Death in TDP-43 Proteinopathies

Biomedicines ◽

10.3390/biomedicines9040376 ◽

2021 ◽

Vol 9 (4) ◽

pp. 376

Author(s):

Chantal B. Lucini ◽

Ralf J. Braun

Keyword(s):

Cell Death ◽

Oxygen Species ◽

In Vivo Models ◽

Dependent Cell ◽

Cell Death Mechanisms ◽

Sting Pathway ◽

Mitochondrial Membrane Permeabilization

In the last decade, pieces of evidence for TDP-43-mediated mitochondrial dysfunction in neurodegenerative diseases have accumulated. In patient samples, in vitro and in vivo models have shown mitochondrial accumulation of TDP-43, concomitantly with hallmarks of mitochondrial destabilization, such as increased production of reactive oxygen species (ROS), reduced level of oxidative phosphorylation (OXPHOS), and mitochondrial membrane permeabilization. Incidences of TDP-43-dependent cell death, which depends on mitochondrial DNA (mtDNA) content, is increased upon ageing. However, the molecular pathways behind mitochondrion-dependent cell death in TDP-43 proteinopathies remained unclear. In this review, we discuss the role of TDP-43 in mitochondria, as well as in mitochondrion-dependent cell death. This review includes the recent discovery of the TDP-43-dependent activation of the innate immunity cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) pathway. Unravelling cell death mechanisms upon TDP-43 accumulation in mitochondria may open up new opportunities in TDP-43 proteinopathy research.

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The gut microbial metabolite trimethylamine N-oxide aggravates GVHD by inducing M1 macrophage polarization in mice

Blood ◽

10.1182/blood.2019003990 ◽

2020 ◽

Vol 136 (4) ◽

pp. 501-515 ◽

Cited By ~ 8

Author(s):

Kunpeng Wu ◽

Yan Yuan ◽

Huihui Yu ◽

Xin Dai ◽

Shu Wang ◽

...

Keyword(s):

Nlrp3 Inflammasome ◽

Macrophage Polarization ◽

Short Chain Fatty Acids ◽

Inflammasome Activation ◽

Microbial Metabolites ◽

M1 Macrophage ◽

The Impact

Abstract The diversity of the human microbiome heralds the difference of the impact that gut microbial metabolites exert on allogenic graft-versus-host (GVH) disease (GVHD), even though short-chain fatty acids and indole were demonstrated to reduce its severity. In this study, we dissected the role of choline-metabolized trimethylamine N-oxide (TMAO) in the GVHD process. Either TMAO or a high-choline diet enhanced the allogenic GVH reaction, whereas the analog of choline, 3,3-dimethyl-1-butanol reversed TMAO-induced GVHD severity. Interestingly, TMAO-induced alloreactive T-cell proliferation and differentiation into T-helper (Th) subtypes was seen in GVHD mice but not in in vitro cultures. We thus investigated the role of macrophage polarization, which was absent from the in vitro culture system. F4/80+CD11b+CD16/32+ M1 macrophage and signature genes, IL-1β, IL-6, TNF-α, CXCL9, and CXCL10, were increased in TMAO-induced GVHD tissues and in TMAO-cultured bone marrow–derived macrophages (BMDMs). Inhibition of the NLRP3 inflammasome reversed TMAO-stimulated M1 features, indicating that NLRP3 is the key proteolytic activator involved in the macrophage’s response to TMAO stimulation. Consistently, mitochondrial reactive oxygen species and enhanced NF-κB nuclear relocalization were investigated in TMAO-stimulated BMDMs. In vivo depletion of NLRP3 in GVHD recipients not only blocked M1 polarization but also reversed GVHD severity in the presence of TMAO treatment. In conclusion, our data revealed that TMAO-induced GVHD progression resulted from Th1 and Th17 differentiation, which is mediated by the polarized M1 macrophage requiring NLRP3 inflammasome activation. It provides the link among the host choline diet, microbial metabolites, and GVH reaction, shedding light on alleviating GVHD by controlling choline intake.

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The P2Y6 Receptor Stimulates Bone Resorption by Osteoclasts

Endocrinology ◽

10.1210/en.2011-1073 ◽

2011 ◽

Vol 152 (10) ◽

pp. 3706-3716 ◽

Cited By ~ 22

Author(s):

Isabel R. Orriss ◽

Ning Wang ◽

Geoffrey Burnstock ◽

Timothy R. Arnett ◽

Alison Gartland ◽

...

Keyword(s):

Cell Function ◽

Bone Cell ◽

Extracellular Nucleotides ◽

P2y6 Receptor ◽

Tomographic Analysis ◽

G Protein Coupled ◽

Resorptive Activity

Accumulating evidence indicates that extracellular nucleotides, signaling through P2 receptors, play a significant role in bone remodeling. Osteoclasts (the bone-resorbing cell) and osteoblasts (the bone-forming cell) display expression of the G protein-coupled P2Y6 receptor, but the role of this receptor in modulating cell function is unclear. Here, we demonstrate that extracellular UDP, acting via P2Y6 receptors, stimulates the formation of osteoclasts from precursor cells, while also enhancing the resorptive activity of mature osteoclasts. Furthermore, osteoclasts derived from P2Y6 receptor-deficient (P2Y6R−/−) animals displayed defective function in vitro. Using dual energy x-ray absorptiometry scanning and microcomputed tomographic analysis we showed that P2Y6R−/− mice have increased bone mineral content, cortical bone volume, and cortical thickness in the long bones and spine, whereas trabecular bone parameters were unaffected. Histomorphometric analysis showed the perimeter of the bone occupied by osteoclasts on the endocortical and trabecular surfaces was decreased in P2Y6R−/− mice. Taken together these results show the P2Y6 receptor may play an important role in the regulation of bone cell function in vivo.

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RhTrx-1 ameliorates miroglial neuroinflammation after cerebral ischemic stroke

10.21203/rs.3.rs-18172/v1 ◽

2020 ◽

Author(s):

Yang Jiao ◽

Jianjian Wang ◽

Huixue Zhang ◽

Yuze Cao ◽

Yang Qu ◽

...

Keyword(s):

Ischemic Stroke ◽

Inflammatory Response ◽

Inflammatory Responses ◽

Inflammatory Factors ◽

Experimental Stroke ◽

Inflammasome Activation ◽

Cerebral Ischemic

Abstract Background Microglia are rapidly activated after ischemic stroke and participate in the occurrence of neuroinflammation, which exacerbates the injury of ischemic stroke. Receptor Interacting Serine Threonine Kinase 1 (RIPK1) is thought to be involved in the development of inflammatory responses, but its role in ischemic microglia remains unclear. Here, we applied recombinant human thioredoxin-1 (rhTrx-1), a potential neuroprotective agent, to explore the role of rhTrx-1 in inhibiting RIPK1-mediated neuroinflammatory responses in microglia. Method Middle cerebral artery occlusion (MCAO) and Oxygen and glucose deprivation (OGD) were conducted for in vivo and in vitro experimental stroke models. The expression of RIPK1 in microglia after ischemia was examined. The inflammatory response of microglia was analyzed after treatment with rhTrx-1 and Necrostatin-1 (Nec-1, inhibitors of RIPK1), and the mechanisms were explored. In addition, the effects of rhTrx-1 on neurobehavioral deficits and cerebral infarct volume were examined. Results RIPK1 expression was detected in microglia after ischemia. Molecular docking results showed that rhTrx-1 could directly bind to RIPK1. In vitro experiments found that rhTrx-1 reduced necroptosis, mitochondrial membrane potential damage, Reactive oxygen species (ROS) accumulation and NLR Family, pyrin domain-containing 3 protein (NLRP3) inflammasome activation by inhibiting RIPK-1 expression, and regulated microglial M1/M2 phenotypic changes, thereby reducing the release of inflammatory factors. Consistently, in vivo experiments found that rhTrx-1 treatment attenuated cerebral ischemic injury by inhibiting the inflammatory response. Conclusion Our study demonstrates the role of RIPK1 in microglia-arranged neuroinflammation after cerebral ischemia. Administration of rhTrx-1 provides neuroprotection in ischemic stroke-induced microglial neuroinflammation by inhibiting RIPK1 expression.

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Inhibitory Role of Berberine, an Isoquinoline Alkaloid, on NLRP3 Inflammasome Activation for the Treatment of Inflammatory Diseases

Molecules ◽

10.3390/molecules26206238 ◽

2021 ◽

Vol 26 (20) ◽

pp. 6238

Author(s):

Paromita Sarbadhikary ◽

Blassan P. George ◽

Heidi Abrahamse

Keyword(s):

Nlrp3 Inflammasome ◽

Inflammatory Diseases ◽

In Vivo Studies ◽

Inflammasome Activation ◽

Inflammatory Disorders ◽

Nlrp3 Inflammasome Activation ◽

Anti Inflammatory

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.

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Elesclomol-induced increase of mitochondrial reactive oxygen species impairs glioblastoma stem-like cell survival and tumor growth

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-02031-4 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Mariachiara Buccarelli ◽

Quintino Giorgio D’Alessandris ◽

Paola Matarrese ◽

Cristiana Mollinari ◽

Michele Signore ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Cell Death ◽

Molecular Mechanisms ◽

Reactive Oxygen ◽

Strong Increase ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species

Abstract Background Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor in adults, characterized by a poor prognosis mainly due to recurrence and therapeutic resistance. It has been widely demonstrated that glioblastoma stem-like cells (GSCs), a subpopulation of tumor cells endowed with stem-like properties is responsible for tumor maintenance and progression. Moreover, it has been demonstrated that GSCs contribute to GBM-associated neovascularization processes, through different mechanisms including the transdifferentiation into GSC-derived endothelial cells (GdECs). Methods In order to identify druggable cancer-related pathways in GBM, we assessed the effect of a selection of 349 compounds on both GSCs and GdECs and we selected elesclomol (STA-4783) as the most effective agent in inducing cell death on both GSC and GdEC lines tested. Results Elesclomol has been already described to be a potent oxidative stress inducer. In depth investigation of the molecular mechanisms underlying GSC and GdEC response to elesclomol, confirmed that this compound induces a strong increase in mitochondrial reactive oxygen species (ROS) in both GSCs and GdECs ultimately leading to a non-apoptotic copper-dependent cell death. Moreover, combined in vitro treatment with elesclomol and the alkylating agent temozolomide (TMZ) enhanced the cytotoxicity compared to TMZ alone. Finally, we used our experimental model of mouse brain xenografts to test the combination of elesclomol and TMZ and confirmed their efficacy in vivo. Conclusions Our results support further evaluation of therapeutics targeting oxidative stress such as elesclomol with the aim of satisfying the high unmet medical need in the management of GBM.

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The role of IL-1 in gout: from bench to bedside

Rheumatology ◽

10.1093/rheumatology/kex449 ◽

2017 ◽

Vol 57 (suppl_1) ◽

pp. i12-i19 ◽

Cited By ~ 10

Author(s):

Alexander So ◽

Alexandre Dumusc ◽

Sonia Nasi

Keyword(s):

Animal Studies ◽

Reactive Oxygen Species Generation ◽

Inflammasome Activation ◽

Acute Gout ◽

Oxygen Species ◽

Biological Responses ◽

Novel Approach ◽

The Subject

Abstract The translation of our knowledge of the biology of MSU crystal-induced IL-1 secretion gives rise to new targets and therapeutic strategies in the treatment of acute gout. The NACHT, LRR and PYD domains-containing protein 3 inflammasome is key to this, and is the subject of intense research. Novel pathways that modulate inflammasome activation, reactive oxygen species generation and extracellular processing of IL-1 have been described and show promise in in vitro and animal studies. Meanwhile, blocking IL-1 by various IL-1 inhibitors has shown the validity of this concept. Patients with acute gout treated with these inhibitors showed positive clinical and biological responses. More work needs to be performed to assess the risk/benefit profile of anti-IL-1 therapies as well as to identify those who will benefit the most from this novel approach to the treatment of gout.

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Abstract 15983: Increased Mitochondrial Reactive Oxygen Species Lead to Deleterious JNK Signaling and Ischemia-Reperfusion Injury in AMPK-Inactivated Hearts

Circulation ◽

10.1161/circ.130.suppl_2.15983 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Vlad G Zaha ◽

Dake Qi ◽

Hui-Young Lee ◽

Xiaoyue Hu ◽

Xiaohong Wu ◽

...

Keyword(s):

Ischemia Reperfusion ◽

Reactive Oxygen ◽

Myocardial Necrosis ◽

Ros Production ◽

Oxygen Species ◽

Mitochondrial Reactive Oxygen Species ◽

Jnk Signaling ◽

Mitochondrial Ros

AMP-activated kinase (AMPK) is a key stress responsive kinase that regulates cellular adaptation to metabolic stress. Inactivation of AMPK in “kinase-dead” (KD) mice increases myocardial damage following ischemia-reperfusion (IR). We have also shown decreased mitochondrial respiration and increased mitochondrial reactive oxygen species (ROS) production and susceptibility to mitochondrial transition pore opening in KD hearts following IR. The aim of this study was to establish the importance of mitochondrial ROS production and downstream deleterious signaling to mediate tissue damage in absence of active AMPK in the heart. Detoxification of mitochondrial ROS requires conversion of hydrogen peroxide to water, therefore, we studied the effect of transgenic expression of mitochondrial catalase (MCAT) in wild type (WT) and KD mice. MCAT prevents mitochondrial hydrogen peroxide production independent of mitochondrial energy production. Myocardial necrosis was assessed in vitro after global ischemia-reperfusion and in vivo after LAD ligation and reperfusion. Mitogen activated protein kinase kinase 4 (MKK4) and downstream c-Jun terminal kinase (JNK) expression and phosphorylation was assessed in vivo. Increased necrosis in KD hearts following mild global ischemia (15 minutes) - reperfusion (10 minutes) in vitro, was prevented by expression of MCAT (WT vs. KD 17.8±4.1 vs. 50±4.1%, p<0.05 and MCAT-WT vs. MCAT-KD 16.9±4.8 vs. 29.3±4.4%, n.s., and factorial p<0.05). Total JNK protein was not increased in WT and KD hearts with or without expression of MCAT. After coronary occlusion in vivo, KD mice showed increased cardiac activation of MKK4/JNK pathway (p<0.05) as well as greater myocardial necrosis (p<0.05). MCAT expression prevented the excessive cardiac JNK activation observed during IR in KD mice in vivo. Inhibition of JNK with SP600125 (10μM) during in vivo IR also resulted in a significant decrease in necrosis in KD hearts (WT vs. KD 9.1±0.7 vs. 28.2±2.9%, p<0.05 and WT vs. KD with SP600125 8.5±0.5 vs. 10.2±1.1%, n.s. and factorial p<0.05, percentage of equivalent area at risk). Thus, AMPK activation during IR prevents excess mitochondrial reactive oxygen production and consequent JNK signaling, thus protecting against myocardial injury.

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