Anti-Inflammatory Activity of Lobaric Acid via Suppressing NF-κB/MAPK Pathways or NLRP3 Inflammasome Activation

Planta Medica ◽  
2018 ◽  
Vol 85 (04) ◽  
pp. 302-311 ◽  
Author(s):  
Hee-Weon Lee ◽  
JinWook Kim ◽  
Joung-Han Yim ◽  
Hong-Kum Lee ◽  
Suhkneung Pyo
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Biological Activities ◽  
Inflammasome Activation ◽  
Mapk Pathways ◽  
Nlrp3 Inflammasome Activation ◽  
Mitogen Activated Protein ◽  
Factor Α ◽  
Necrosis Factor

Lobaric acid (LA) is a constituent of the lichen Stereocaulon alpinum. LA has multiple biological activities, including antibacterial and antioxidant ones. The purpose of this study was to investigate the effect of LA and its mechanism on lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. Macrophages were pretreated with different concentrations of LA (0.2 – 20 µM), followed by LPS stimulation. LA treatment of LPS stimulated macrophages decreased their nitric oxide production and the expression of cyclooxygenase-2 and prostaglandin E2. LA also significantly reduced the production of tumor necrosis factor-α and interleukin (IL)-6 by inhibiting the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB). Additionally, LA inhibited the production of IL-1β and IL-18, as well as caspase-1 maturation, by inhibition of NLRP3 inflammasome activation in LPS/ATP-stimulated cells. These results strongly suggest that LA could inhibit inflammation by downregulating NF-κB/MAPK pathways and NLRP3 inflammasome activation in activated macrophages. These results reveal a new therapeutic approach to modulate inflammatory diseases linked to deregulated inflammasome activities.

scholarly journals Cullin1 represses systematic inflammasome activation by binding and catalyzing NLRP3 ubiquitination

2018 ◽  
Author(s):  
Pin Wan ◽  
Qi Zhang ◽  
Weiyong Liu ◽  
Yaling Jia ◽  
Tianci Wang ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Critical Role ◽  
Inflammasome Activation ◽  
First Line ◽  
Physiological Conditions ◽  
Nlrp3 Inflammasome Activation ◽  
Inflammatory Stimuli ◽  
Cellular Stresses

AbstractActivation of the NLRP3 inflammasome is a key process of host immune response, the first line of defense against cellular stresses and pathogen infections. However, excessive inflammasome activation damages the hosts, and thus it must be precisely controlled. The mechanism underlying the repression of systematic inflammasome activation remains largely unknown. This study reveals that CUL1, a key component of the SCF E3 ligase, plays a critical role in regulation of the inflammasome. CUL1 suppresses the inflammasome activation in HEK293T cells, inhibits endogenous NLRP3 in macrophages, and represses inflammatory responses in C57BL/6 mice. Under normal physiological conditions, CUL1 interacts with NLRP3 to disrupt the inflammasome assembly, and catalyzes NLRP3 ubiquitination to repress the inflammasome activation. In response to inflammatory stimuli, CUL1 disassociates from NLRP3 to release the repression of NLRP3 inflammasome activation. This work reveals a distinct mechanism underlying the repression of inflammasome activation under physiological conditions and the induction of inflammasome activation in response to inflammatory stimuli, and thus provides insights into the prevention and treatment of infectious and inflammatory diseases.

scholarly journals Thioredoxin-1 distinctly promotes NF-κB target DNA binding and NLRP3 inflammasome activation independently of Txnip

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jonathan Muri ◽  
Helen Thut ◽  
Qian Feng ◽  
Manfred Kopf
Keyword(s):  
Dna Binding ◽  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Critical Role ◽  
Myeloid Cell ◽  
Antioxidant Systems ◽  
Inflammasome Activation ◽  
Nlrp3 Inflammasome Activation ◽  
Thioredoxin 1

Antioxidant systems, such as the thioredoxin-1 (Trx1) pathway, ensure cellular redox homeostasis. However, how such systems regulate development and function of myeloid cells is barely understood. Here we show that in contrast to its critical role in T cells, the murine Trx1 system is dispensable for steady-state myeloid-cell hematopoiesis due to their capacity to tap the glutathione/glutaredoxin pathway for DNA biosynthesis. However, the Trx1 pathway instrumentally enables nuclear NF-κB DNA-binding and thereby pro-inflammatory responses in monocytes and dendritic cells. Moreover, independent of this activity, Trx1 is critical for NLRP3 inflammasome activation and IL-1β production in macrophages by detoxifying excessive ROS levels. Notably, we exclude the involvement of the Trx1 inhibitor Txnip as a redox-sensitive ligand of NLRP3 as previously proposed. Together, this study suggests that targeting Trx1 may be exploited to treat inflammatory diseases.

scholarly journals Bisphenol A disrupts inflammatory responses via Nod-like receptor protein 3 pathway in macrophages

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Hee-Weon Lee ◽  
Sang Keun Ha ◽  
Yoonsook Kim
Keyword(s):  
Bisphenol A ◽  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Receptor Protein ◽  
Prostaglandin E ◽  
Inflammasome Activation ◽  
No Production ◽  
Dental Resins ◽  
Nlrp3 Inflammasome Activation ◽  
Mitogen Activated Protein

AbstractBisphenol A (BPA) is a harmful endocrine disruptor that is found in polycarbonate plastics such as plastic food containers and in epoxy resins such as dental resins. In the current study, we investigated the effect of BPA on function of inflammatory responses involving activation of Nod-like receptor protein 3 (NLRP3) inflammasome. Treatment with BPA decreased nitric oxide (NO) production and expression levels of inducible NO synthase (iNOS), prostaglandin E2 (PGE2), and cyclooxygenase (Cox)-2 in RAW 264.7 macrophages. BPA also suppressed activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B activity (NF-κB). BPA significantly down-regulated the secretion of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and IL-18. The decreased production of IL-1β and IL-18 induced by BPA was associated with inactivation of the activity of the NLRP3 inflammasome. Collectively, these data suggested that BPA could act as a disruptor of the inflammation activity by regulating the NF-κB/MAPK pathways and NLRP3 inflammasome activation.

scholarly journals SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pan Pan ◽  
Miaomiao Shen ◽  
Zhenyang Yu ◽  
Weiwei Ge ◽  
Keli Chen ◽  
...  
Keyword(s):  
Lung Injury ◽  
Nlrp3 Inflammasome ◽  
Cultured Cells ◽  
Inflammatory Responses ◽  
Specific Inhibitor ◽  
Inflammasome Activation ◽  
N Protein ◽  
Distinct Mechanism ◽  
Nlrp3 Inflammasome Activation ◽  
Proinflammatory Responses

AbstractExcessive inflammatory responses induced upon SARS-CoV-2 infection are associated with severe symptoms of COVID-19. Inflammasomes activated in response to SARS-CoV-2 infection are also associated with COVID-19 severity. Here, we show a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation. N protein facilitates maturation of proinflammatory cytokines and induces proinflammatory responses in cultured cells and mice. Mechanistically, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates NLRP3 inflammasome assembly. More importantly, N protein aggravates lung injury, accelerates death in sepsis and acute inflammation mouse models, and promotes IL-1β and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production are blocked by MCC950 (a specific inhibitor of NLRP3) and Ac-YVAD-cmk (an inhibitor of caspase-1). Therefore, this study reveals a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses.

Psidium guajava Flavonoids Prevent NLRP3 Inflammasome Activation and Alleviate the Pancreatic Fibrosis in a Chronic Pancreatitis Mouse Model

2021 ◽  
Vol 49 (08) ◽  
pp. 2001-2015
Author(s):  
Guixian Zhang ◽  
Liming Tang ◽  
Hongbin Liu ◽  
Dawei Liu ◽  
Manxue Wang ◽  
...  
Keyword(s):  
Chronic Pancreatitis ◽  
Signaling Pathway ◽  
Nlrp3 Inflammasome ◽  
Target Genes ◽  
Inflammatory Responses ◽  
Psidium Guajava ◽  
Pancreatic Fibrosis ◽  
Inflammasome Activation ◽  
Caspase 1 ◽  
Nlrp3 Inflammasome Activation

Chronic pancreatitis (CP) is a multifactorial, inflammatory syndrome characterized by acinar atrophy and fibrosis. Activation of NOD-like receptors family pyrin domain-containing 3 (NLRP3) inflammasome is a central mediator of multiple chronic inflammatory responses and chronic fibrosis including pancreatic fibrosis in CP. The Psidium guajavaleaf is widely used in traditional medicine for the treatment of chronic inflammation, but the anti-inflammatory effect of Psidium guajavaleaf on CP has not yet been revealed. In this study, we investigated whether the extract of total flavonoids from Psidium guajava leaves (TFPGL) plays a therapeutic mechanism on CP through NLRP3 inflammasome signaling pathway in a mouse CP model. The H&E and acid-Sirius red staining indicted that TFPGL attenuated the inflammatory cell infiltration and fibrosis significantly. The results of immunohistological staining, western blot and RT-qPCR showed that the expressions of NLRP3 and caspase-1 were significantly increased in the CP model group, while TFPGL significantly decreased the NLRP3 and caspase-1 expression at both the gene and protein levels. Moreover, ELISA assay was used to examine the levels of NLRP3 inflammasome target genes, such as caspase-1, IL-1[Formula: see text] and IL-18. We found that TFPGL treatment decreased the expression of caspase-1, IL-1[Formula: see text] and IL-18, which is critical for the NLRP3 inflammasome signaling pathway and inflammation response significantly. These results demonstrated that TFPGL attenuated pancreatic inflammation and fibrosis via preventing NLRP3 inflammasome activation and TFPGL can be used as a potential therapeutic agent for CP.

scholarly journals ROS-Mediated NLRP3 Inflammasome Activation in Brain, Heart, Kidney, and Testis Ischemia/Reperfusion Injury

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Letteria Minutoli ◽  
Domenico Puzzolo ◽  
Mariagrazia Rinaldi ◽  
Natasha Irrera ◽  
Herbert Marini ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Current Knowledge ◽  
Ischemia Reperfusion ◽  
Ion Homeostasis ◽  
Inflammasome Activation ◽  
Mortality And Morbidity ◽  
Arterial Blood ◽  
Nlrp3 Inflammasome Activation

Ischemia and reperfusion (I/R) causes a reduction in arterial blood supply to tissues, followed by the restoration of perfusion and consequent reoxygenation. The reestablishment of blood flow triggers further damage to the ischemic tissue through reactive oxygen species (ROS) accumulation, interference with cellular ion homeostasis, and inflammatory responses to cell death. In normal conditions, ROS mediate important beneficial responses. When their production is prolonged or elevated, harmful events are observed with peculiar cellular changes. In particular, during I/R, ROS stimulate tissue inflammation and induce NLRP3 inflammasome activation. The mechanisms underlying the activation of NLRP3 are several and not completely elucidated. It was recently shown that NLRP3 might sense directly the presence of ROS produced by normal or malfunctioning mitochondria or indirectly by other activators of NLRP3. Aim of the present review is to describe the current knowledge on the role of NLRP3 in some organs (brain, heart, kidney, and testis) after I/R injury, with particular regard to the role played by ROS in its activation. Furthermore, as no specific therapy for the prevention or treatment of the high mortality and morbidity associated with I/R is available, the state of the art of the development of novel therapeutic approaches is illustrated.

scholarly journals Inhibitory Effect and Mechanism of Arctium lappa Extract on NLRP3 Inflammasome Activation

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Young-Kyu Kim ◽  
Sushruta Koppula ◽  
Do-Wan Shim ◽  
Eun-Jung In ◽  
Su-Bin Kwak ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Biological Activities ◽  
Inhibitory Effect ◽  
Inflammasome Activation ◽  
Inhibitory Effects ◽  
Arctium Lappa ◽  
Nlrp3 Inflammasome Activation ◽  
Anti Inflammatory ◽  
Underlying Mechanisms ◽  
Peritonitis Model

Arctium lappa (A. lappa), Compositae, is considered a potential source of nutrition and is used as a traditional medicine in East Asian countries for centuries. Although several studies have shown its biological activities as an anti-inflammatory agent, there have been no reports on A. lappa with regard to regulatory role in inflammasome activation. The purpose of this study was to investigate the inhibitory effects of A. lappa extract (ALE) on NLRP3 inflammasome activation and explore the underlying mechanisms. We found that ALE inhibited IL-1β secretion from NLRP3 inflammasome activated bone marrow derived macrophages but not that secreted by NLRC4 and AIM2 inflammasomes activation. Mechanistic studies revealed that ALE suppressed the ATPase activity of purified NLRP3 and reduced mitochondrial reactive oxygen species (mROS) generated during NLRP3 activation. Therefore, the inhibitory effect of ALE on NLRP3 inflammasome might be attributed to its ability to inhibit the NLRP3 ATPase function and attenuated the mROS during inflammasome activation. In addition, ALE significantly reduced the LPS-induced increase of plasma IL-1β in mouse peritonitis model. These results provide evidence of novel anti-inflammatory mechanisms of A. lappa, which might be used for therapeutic applications in the treatment of NLRP3 inflammasome-associated inflammatory disorders.

scholarly journals TRPV1 channel mediates NLRP3 inflammasome-dependent neuroinflammation in microglia

2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Yahui Zhang ◽  
Baohua Hou ◽  
Peiyu Liang ◽  
Xin Lu ◽  
Yifan Wu ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Transient Receptor Potential ◽  
Inflammatory Diseases ◽  
Critical Role ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Inflammasome Activation ◽  
Trpv1 Channel ◽  
Nlrp3 Inflammasome Activation

AbstractMultiple sclerosis (MS) is a chronic inflammatory autoimmune disease in the central nervous system (CNS). The NLRP3 inflammasome is considered an important regulator of immunity and inflammation, both of which play a critical role in MS. However, the underlying mechanism of NLRP3 inflammasome activation is not fully understood. Here we identified that the TRPV1 (transient receptor potential vanilloid type 1) channel in microglia, as a Ca2+ influx-regulating channel, played an important role in NLRP3 inflammasome activation. Deletion or pharmacological blockade of TRPV1 inhibited NLRP3 inflammasome activation in microglia in vitro. Further research revealed that TRPV1 channel regulated ATP-induced NLRP3 inflammasome activation through mediating Ca2+ influx and phosphorylation of phosphatase PP2A in microglia. In addition, TRPV1 deletion could alleviate mice experimental autoimmune encephalomyelitis (EAE) and reduce neuroinflammation by inhibiting NLRP3 inflammasome activation. These data suggested that the TRPV1 channel in microglia can regulate NLRP3 inflammasome activation and consequently mediate neuroinflammation. Meanwhile, our study indicated that TRPV1–Ca2+–PP2A pathway may be a novel regulator of NLRP3 inflammasome activation, pointing to TRPV1 as a potential target for CNS inflammatory diseases.

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