scholarly journals Neutrophil microvesicles resolve gout by inhibiting C5a-mediated priming of the inflammasome

2015 ◽  
Vol 75 (6) ◽  
pp. 1236-1245 ◽  
Author(s):  
Arun Cumpelik ◽  
Barbara Ankli ◽  
Daniel Zecher ◽  
Jürg A Schifferli
Keyword(s):  
Acute Inflammation ◽  
Gouty Arthritis ◽  
Surface Expression ◽  
Joint Disease ◽  
Inflammasome Activation ◽  
Acute Gout ◽  
Mediated Priming

ObjectivesGout is a highly inflammatory but self-limiting joint disease induced by the precipitation of monosodium urate (MSU) crystals. While it is well established that inflammasome activation by MSU mediates acute inflammation, little is known about the mechanism controlling its spontaneous resolution. The aim of this study was to analyse the role of neutrophil-derived microvesicles (PMN-Ecto) in the resolution of acute gout.MethodsPMN-Ecto were studied in a murine model of MSU-induced peritonitis using C57BL/6, MerTK−/−and C5aR−/−mice. The peritoneal compartment was assessed for the number of infiltrating neutrophils (PMN), neutrophil microvesicles (PMN-Ecto), cytokines (interleukin-1β, TGFβ) and complement factors (C5a). Human PMN-Ecto were isolated from exudates of patients undergoing an acute gouty attack and functionally tested in vitro.ResultsC5a generated after the injection of MSU primed the inflammasome for IL-1β release. Neutrophils infiltrating the peritoneum in response to C5a released phosphatidylserine (PS)-positive PMN-Ecto early on in the course of inflammation. These PMN-Ecto in turn suppressed C5a priming of the inflammasome and consequently inhibited IL-1β release and neutrophil influx. PMN-Ecto-mediated suppression required surface expression of the PS-receptor MerTK and could be reproduced using PS-expressing liposomes. In addition, ectosomes triggered the release of TGFβ independent of MerTK. TGFβ, however, was not sufficient to control acute MSU-driven inflammation in vivo. Finally, PMN-Ecto from joint aspirates of patients with gouty arthritis had similar anti-inflammatory properties.ConclusionsPMN-Ecto-mediated control of inflammasome-driven inflammation is a compelling concept of autoregulation initiated early on during PMN activation in gout.

scholarly journals Cyr61 Promotes Inflammation of a Gouty Arthritis Model in Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Mi Zhou ◽  
Kan Ze ◽  
Liang Hua ◽  
Liu Liu ◽  
Le Kuai ◽  
...  
Keyword(s):  
Western Blot ◽  
Signaling Pathway ◽  
Acute Inflammation ◽  
Gouty Arthritis ◽  
Dependent Manner ◽  
Monosodium Urate ◽  
Synovial Tissues

Background. Cyr61 is considered a novel proinflammatory factor. Gouty arthritis (GA) is a self-limited inflammatory reaction caused by monosodium urate (MSU) crystals. In this study, we assessed the role of Cyr61 in the inflammatory process of GA. Methods. We investigated the expression of Cyr61 in MSU-induced rat gout models and MSU-stimulated rat fibroblast-like synovial (FLS) cells. After inhibiting the expression of Cyr61, levels of IL-1β, TNF-α, and IL-6 were detected by ELISA, qPCR, western blot, and immunohistochemical methods. We probed the downstream NF-κB signaling pathway using the NF-κB inhibitor PDTC, and levels of NF-κB and p-NF-κB were detected by western blot and qPCR. Results. Our results demonstrate that Cyr61 plays a potent role in the formation of local inflammation in vitro and in vivo. Cyr61 was highly expressed in synovial tissues of gout models, and the expression of Cyr61 protein was also significantly increased in MSU-stimulated FLS cells. Cyr61 promoted MSU-induced acute inflammation via the NF-κB signaling pathway. Conclusions. Our study has revealed that Cyr61 is an important regulatory factor for the initiation of inflammation in GA. The high expression of Cyr61 protein can induce synovial cells to produce many inflammatory cytokines, such as IL-1β, TNF-α, and IL-6, partly in an NF-κB-dependent manner. Thus, inhibition of Cyr61 could be a new target and strategy for the prevention and treatment of GA.

Mechanosensitive TRPV4 is required for crystal-induced inflammation

2021 ◽  
pp. annrheumdis-2021-220295
Author(s):  
Zhou Lan ◽  
Lvyi Chen ◽  
Jing Feng ◽  
Zili Xie ◽  
Zhiyong Liu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Gouty Arthritis ◽  
Inflammasome Activation ◽  
Acute Gout ◽  
Human Pbmcs ◽  
Nlrp3 Inflammasome Activation ◽  
Gout Flares

Crystal structures activate innate immune cells, especially macrophages and initiate inflammatory responses. We aimed to understand the role of the mechanosensitive TRPV4 channel in crystal-induced inflammation. Real-time RT-PCR, RNAscope in situ hybridisation, and Trpv4eGFP mice were used to examine TRPV4 expression and whole-cell patch-clamp recording and live-cell Ca2+ imaging were used to study TRPV4 function in mouse synovial macrophages and human peripheral blood mononuclear cells (PBMCs). Both genetic deletion and pharmacological inhibition approaches were used to investigate the role of TRPV4 in NLRP3 inflammasome activation induced by diverse crystals in vitro and in mouse models of crystal-induced pain and inflammation in vivo. TRPV4 was functionally expressed by synovial macrophages and human PBMCs and TRPV4 expression was upregulated by stimulation with monosodium urate (MSU) crystals and in human PBMCs from patients with acute gout flares. MSU crystal-induced gouty arthritis were significantly reduced by either genetic ablation or pharmacological inhibition of TRPV4 function. Mechanistically, TRPV4 mediated the activation of NLRP3 inflammasome by diverse crystalline materials but not non-crystalline NLRP3 inflammasome activators, driving the production of inflammatory cytokine interleukin-1β which elicited TRPV4-dependent inflammatory responses in vivo. Moreover, chemical ablation of the TRPV1-expressing nociceptors significantly attenuated the MSU crystal-induced gouty arthritis. In conclusion, TRPV4 is a common mediator of inflammatory responses induced by diverse crystals through NLRP3 inflammasome activation in macrophages. TRPV4-expressing resident macrophages are critically involved in MSU crystal-induced gouty arthritis. A neuroimmune interaction between the TRPV1-expressing nociceptors and the TRPV4-expressing synovial macrophages contributes to the generation of acute gout flares.

scholarly journals Selonsertib Alleviates the Progression of Rat Osteoarthritis: An in vitro and in vivo Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiyuan Yan ◽  
Yingchi Zhang ◽  
Gaohong Sheng ◽  
Bowei Ni ◽  
Yifan Xiao ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Cartilage Damage ◽  
Cartilage Degradation ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Therapeutic Effects ◽  
Exact Role

Osteoarthritis (OA) is a prevalent degenerative joint disease. Its development is highly associated with inflammatory response and apoptosis in chondrocytes. Selonsertib (Ser), the inhibitor of Apoptosis Signal-regulated kinase-1 (ASK1), has exhibited multiple therapeutic effects in several diseases. However, the exact role of Ser in OA remains unclear. Herein, we investigated the anti-arthritic effects as well as the potential mechanism of Ser on rat OA. Our results showed that Ser could markedly prevent the IL-1β-induced inflammatory reaction, cartilage degradation and cell apoptosis in rat chondrocytes. Meanwhile, the ASK1/P38/JNK and NFκB pathways were involved in the protective roles of Ser. Furthermore, intra-articular injection of Ser could significantly alleviate the surgery induced cartilage damage in rat OA model. In conclusion, our work provided insights into the therapeutic potential of Ser in OA, indicating that Ser might serve as a new avenue in OA treatment.

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

Blood ◽  
2020 ◽  
Vol 136 (4) ◽  
pp. 501-515 ◽  
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.

scholarly journals Granulopoiesis inhibition in acute inflammation: comparative studies in healthy and leukaemic mice

1992 ◽  
Vol 1 (3) ◽  
pp. 171-175
Author(s):  
Mohamad Hamood ◽  
Francis Corazza ◽  
Pierre Francois Bluche ◽  
Hassan El Teraifi ◽  
Pierre Fondu
Keyword(s):  
Acute Inflammation ◽  
Regulatory Mechanism ◽  
Diffusion Chamber ◽  
Colony Growth ◽  
Cell Content ◽  
Humoral Factors ◽  
Leukaemic Cells

It was demonstrated previously that mice undergoing an inflammatory reaction induced by subcutaneous (SC) implantation of copper rods, produce humoral factors that initially enhance, but subsequently inhibit, diffusion chamber (DC) granulopoiesis. This provided evidence that granulopoiesis is under the control of both humoral stimulators and inhibitors. In order to test the granulopoietic regulatory mechanism in leukaemic mice, we investigated the regulatory role of granulopoietic humoral inhibitors during in vivo granulopoiesis. We noticed that mice suffering from acute myeloid leukaemia (AML) are unable to augment the production of these humoral inhibitory factors when acute inflammation is induced, since no change in DC cell content was observed with or without prior inflammation. Moreover, unlike healthy mice, the serum of leukaemic mice withdrawn during the inhibition phase of acute inflammation did not show any inhibitory activity toward granulocyte—monocyte (GM) colony growth in vitro. Our results also show that increased levels of normal humoral inhibitors do not influence the proliferation and/or differentiation of leukaemic cells implanted in diffusion chamber cultures.

scholarly journals RhTrx-1 ameliorates miroglial neuroinflammation after cerebral ischemic stroke

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.

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

Molecules ◽  
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.

scholarly journals The Role of Monocytes in Gouty Arthritis

2021 ◽  
Author(s):  
◽  
Xiao Liu
Keyword(s):  
Acute Inflammation ◽  
Gouty Arthritis ◽  
Local Environment ◽  
Peritoneal Membrane ◽  
Monocyte Chemoattractant Protein 1 ◽  
Inflammatory Microenvironment ◽  
Culture Techniques ◽  
And Function

<p>Gout is one of the most painful forms of arthritis characterised by the deposition of monosodium urate crystals (MSU) in the joint synovium and the subsequent acute influx of circulating leukocytes. This study investigated the contribution of the inflammatory microenvironment in driving recruited monocyte differentiation and function in acute gouty inflammation. Using the murine peritoneal model of MSU-induced inflammation, the differentiation and functional phenotypes of MSU-recruited monocytes were compared in normal acute inflammation and in an inflammatory environment depleted of resident macrophages and infiltrating neutrophils. In addition, the role of the local environment in producing monocyte chemoattractant protein-1 (MCP-1) was investigated. Furthermore, the effect of transmigration on the suppressor phenotype of recruited monocytes was also explored. The pro-inflammatory environment was shown to play a key role in the differentiation and function of recruited monocytes in MSU-induced acute inflammation. In addition, infiltrating neutrophils suppressed the pro-inflammatory abilities of recruited monocytes, which may contribute to the resolution of inflammation. Using both whole peritoneal membrane preparations and in vitro culture techniques, results showed that mesothelial cells lining the peritoneal membrane were a source of MCP-1 production, which contributed to monocyte recruitment. Finally no differences were observed in either the differentiation or functional phenotypes of MSU-recruited monocytes isolated from Glatiramer acetate (GA) treated or non-treated mice. These findings suggest that the inflammatory microenvironment plays a key role in driving the recruitment, differentiation and function of circulating monocytes in the MSU-induced model of acute inflammation.</p>

scholarly journals NLRP3- and AIM2-autonomy in a mouse model of MSU crystal-induced acute inflammation in vivo suggests imiquimod-dependent targeting of Il-1[beta] expression as relevant therapy for gout patients.

2019 ◽  
Author(s):  
Alexandre Mariotte ◽  
Aurore Decauwer ◽  
Chrystelle Po ◽  
Cherine Abou-Faycal ◽  
Angelique Pichot ◽  
...  
Keyword(s):  
Mouse Model ◽  
Acute Inflammation ◽  
Joint Inflammation ◽  
Inflammatory Action ◽  
Recognition Receptor ◽  
Msu Crystals

The role of Monosodium Urate (MSU) crystals in gout pathophysiology is well described, as is the major impact of IL-1b in the inflammatory reaction that constitutes the hallmark of the disease. However, despite the discovery of the NLRP3 inflammasome and its role as a Pattern Recognition Receptor linking the detection of a danger signal (MSU) to IL-1b; secretion in vitro, the precise mechanisms leading to joint inflammation in gout patients are still poorly understood. Here, we provide an extensive clinical, biological and molecular characterization of the acute uratic inflammation mouse model induced by subcutaneous injection of MSU crystals, which accurately mimics human gout. Our work reveals several key features of MSU-dependent inflammation and identifies novel therapeutic opportunities, among which the use of topical application of imiquimod to promote interferon-dependent anti-inflammatory action maybe relevant.

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

Rheumatology ◽  
2017 ◽  
Vol 57 (suppl_1) ◽  
pp. i12-i19 ◽  
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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