scholarly journals DDX3X Links NLRP11 to the Regulation of Type I Interferon Responses and NLRP3 Inflammasome Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Ioannis Kienes ◽  
Sarah Bauer ◽  
Clarissa Gottschild ◽  
Nora Mirza ◽  
Jens Pfannstiel ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Nlrp3 Inflammasome ◽  
Inflammatory Cytokine ◽  
Inflammasome Activation ◽  
Type I ◽  
Dependent Manner ◽  
Type I Ifn ◽  
Central Target ◽  
Nlrp3 Inflammasome Activation ◽  
Lrr Domain

Tight regulation of inflammatory cytokine and interferon (IFN) production in innate immunity is pivotal for optimal control of pathogens and avoidance of immunopathology. The human Nod-like receptor (NLR) NLRP11 has been shown to regulate type I IFN and pro-inflammatory cytokine responses. Here, we identified the ATP-dependent RNA helicase DDX3X as a novel binding partner of NLRP11, using co-immunoprecipitation and LC-MS/MS. DDX3X is known to enhance type I IFN responses and NLRP3 inflammasome activation. We demonstrate that NLRP11 can abolish IKKϵ-mediated phosphorylation of DDX3X, resulting in lower type I IFN induction upon viral infection. These effects were dependent on the LRR domain of NLRP11 that we mapped as the interaction domain for DDX3X. In addition, NLRP11 also suppressed NLRP3-mediated caspase-1 activation in an LRR domain-dependent manner, suggesting that NLRP11 might sequester DDX3X and prevent it from promoting NLRP3-induced inflammasome activation. Taken together, our data revealed DDX3X as a central target of NLRP11, which can mediate the effects of NLRP11 on type I IFN induction as well as NLRP3 inflammasome activation. This expands our knowledge of the molecular mechanisms underlying NLRP11 function in innate immunity and suggests that both NLRP11 and DDX3X might be promising targets for modulation of innate immune responses.

scholarly journals Nod-like Receptors: Critical Intracellular Sensors for Host Protection and Cell Death in Microbial and Parasitic Infections

2021 ◽  
Vol 22 (21) ◽  
pp. 11398
Author(s):  
Abdulkareem Olarewaju Babamale ◽  
Szu-Ting Chen
Keyword(s):  
Innate Immunity ◽  
Cell Death ◽  
Host Defense ◽  
Nucleotide Binding ◽  
Parasitic Infections ◽  
Inflammasome Activation ◽  
Type I ◽  
Dependent Manner ◽  
Type I Ifn ◽  
Microbial Infection

Cell death is an essential immunological apparatus of host defense, but dysregulation of mutually inclusive cell deaths poses severe threats during microbial and parasitic infections leading to deleterious consequences in the pathological progression of infectious diseases. Nucleotide-binding oligomerization domain (NOD)-Leucine-rich repeats (LRR)-containing receptors (NLRs), also called nucleotide-binding oligomerization (NOD)-like receptors (NLRs), are major cytosolic pattern recognition receptors (PRRs), their involvement in the orchestration of innate immunity and host defense against bacteria, viruses, fungi and parasites, often results in the cleavage of gasdermin and the release of IL-1β and IL-18, should be tightly regulated. NLRs are functionally diverse and tissue-specific PRRs expressed by both immune and non-immune cells. Beyond the inflammasome activation, NLRs are also involved in NF-κB and MAPK activation signaling, the regulation of type I IFN (IFN-I) production and the inflammatory cell death during microbial infections. Recent advancements of NLRs biology revealed its possible interplay with pyroptotic cell death and inflammatory mediators, such as caspase 1, caspase 11, IFN-I and GSDMD. This review provides the most updated information that caspase 8 skews the NLRP3 inflammasome activation in PANoptosis during pathogen infection. We also update multidimensional roles of NLRP12 in regulating innate immunity in a content-dependent manner: novel interference of NLRP12 on TLRs and NOD derived-signaling cascade, and the recently unveiled regulatory property of NLRP12 in production of type I IFN. Future prospects of exploring NLRs in controlling cell death during parasitic and microbial infection were highlighted.

PAF and the inflammasome

2019 ◽  
Vol 12 (602) ◽  
pp. eaaz7370
Author(s):  
John F. Foley
Keyword(s):  
Nlrp3 Inflammasome ◽  
Inflammatory Cytokine ◽  
Cytokine Production ◽  
Inflammasome Activation ◽  
Inflammatory Cytokine Production ◽  
Nlrp3 Inflammasome Activation

The phospholipid PAF stimulates NLRP3 inflammasome activation and inflammatory cytokine production independently of its GPCR.

scholarly journals A Synthetic Small Molecule F240B Decreases NLRP3 Inflammasome Activation by Autophagy Induction

2020 ◽  
Vol 11 ◽  
Author(s):  
Chun-Hsien Wu ◽  
Chin Heng Gan ◽  
Lan-Hui Li ◽  
Jen-Che Chang ◽  
Shin-Tai Chen ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Membrane Integrity ◽  
Mechanistic Study ◽  
Autophagic Flux ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Inflammatory Agent ◽  
Nlrp3 Inflammasome Activation ◽  
Autophagy Induction ◽  
Anti Inflammatory

Conjugated polyenes are a class of widely occurring natural products with various biological functions. We previously identified 4-hydroxy auxarconjugatin B (4-HAB) as anti‐inflammatory agent with an IC50 of ~20 µM. In this study, we synthesized a new anti‐inflammatory 4-HAB analogue, F240B, which has an IC50 of less than 1 µM. F240B dose-dependently induced autophagy by increasing autophagic flux, LC3 speck formation and acidic vesicular organelle formation. F240B inhibited NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome activation through autophagy induction. In a mechanistic study, F240B inhibited interleukin (IL)-1β (IL-1β) precursor expression, promoted degradation of NLRP3 and IL-1β, and reduced mitochondrial membrane integrity loss in an autophagy-dependent manner. Additionally, F240B inhibited apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and speck formation without affecting the interaction between NLRP3 and ASC or NIMA-related kinase 7 (NEK7) and double-stranded RNA-dependent kinase (PKR). Furthermore, F240B exerted in vivo anti-inflammatory activity by reducing the intraperitoneal influx of neutrophils and the levels of IL-1β, active caspase-1, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in lavage fluids in a mouse model of uric acid crystal-induced peritonitis. In conclusion, F240B attenuated the NLRP3 inflammasome through autophagy induction and can be developed as an anti-inflammatory agent in the future.

scholarly journals Paclitaxel Enhances the Innate Immunity by Promoting NLRP3 Inflammasome Activation in Macrophages

2019 ◽  
Vol 10 ◽  
Author(s):  
Qiong-zhen Zeng ◽  
Fan Yang ◽  
Chen-guang Li ◽  
Li-hui Xu ◽  
Xian-hui He ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Nlrp3 Inflammasome Activation

scholarly journals Sequential ubiquitination of NLRP3 by RNF125 and Cbl-b limits inflammasome activation and endotoxemia

2020 ◽  
Vol 217 (4) ◽  
Author(s):  
Juan Tang ◽  
Sha Tu ◽  
Guoxin Lin ◽  
Hui Guo ◽  
Chengkai Yan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Lethal Dose ◽  
E3 Ubiquitin Ligase ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Leucine Rich Repeat ◽  
Nlrp3 Inflammasome Activation ◽  
Repeat Domain ◽  
Nlrp3 Inflammasomes ◽  
Lrr Domain

Aberrant NLRP3 inflammasome activation contributes to the development of endotoxemia. The importance of negative regulation of NLRP3 inflammasomes remains poorly understood. Here, we show that the E3 ubiquitin ligase Cbl-b is essential for preventing endotoxemia induced by a sub-lethal dose of LPS via a caspase-11/NLRP3–dependent manner. Further studies show that NLRP3 undergoes both K63- and K48-linked polyubiquitination. Cbl-b binds to the K63-ubiquitin chains attached to the NLRP3 leucine-rich repeat domain (LRR) via its ubiquitin-associated region (UBA) and then targets NLRP3 at K496 for K48-linked ubiquitination and proteasome-mediated degradation. We also identify RNF125 as an additional E3 ubiquitin ligase that initiates K63-linked ubiquitination of the NLRP3 LRR domain. Therefore, NLRP3 is sequentially ubiquitinated by K63- and K48-linked ubiquitination, thus keeping the NLRP3 inflammasomes in check and restraining endotoxemia.

scholarly journals Agnuside Alleviates Synovitis and Fibrosis in Knee Osteoarthritis through the Inhibition of HIF-1α and NLRP3 Inflammasome

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Li Zhang ◽  
Xiaochen Li ◽  
Haosheng Zhang ◽  
Zhengquan Huang ◽  
Nongshan Zhang ◽  
...  
Keyword(s):  
Knee Osteoarthritis ◽  
Nlrp3 Inflammasome ◽  
Type I Collagen ◽  
Vital Role ◽  
Inflammasome Activation ◽  
Type I ◽  
Aseptic Inflammation ◽  
Protein Levels ◽  
Nlrp3 Inflammasome Activation ◽  
Anti Inflammatory

Increasing evidence has shown that NLRP3 inflammasome activation participates in chronic aseptic inflammation and is related to tissue fibrosis. Our last study also revealed the vital role of NLRP3 inflammasome, highly associated with tissue hypoxia, in the onset and development of knee osteoarthritis (KOA). In this study, we tried to find a possible benign intervention for that pathological process. Agnuside (AGN), a nontoxic, natural small molecule isolated from the extract of Vitex negundo L. (Verbenaceae), has been demonstrated to have antioxidation, anti-inflammatory, analgesia, and many other properties as an iridoid glycoside, although its specific target is still unclear. Therefore, we established MIA-induced KOA model rats and investigated the effects of AGN oral gavage on oxygen-containing state, NLRP3 inflammasome, synovitis, and fibrosis in KOA. Pimonidazole staining and HIF-1α immunohistochemical assay both showed that AGN at the oral dose of 6.25 mg/kg can effectively relieve local hypoxia in synovial tissue. Besides, we observed a decrease of HIF-1α, caspase-1, ASC, and NLRP3 after AGN intervention, both in the mRNA and protein levels. In addition, rats treated with the AGN showed less inflammatory reaction and fibrosis, not only in the expression of NLRP3, inflammasome downstream factors IL-1β and IL-18, and fibrosis markers TGF-β, TIMP1, and VEGF but also in the observation of HE staining, anatomical characteristics, Sirius Red staining, and type I collagen immunohistochemistry. Subsequently, we established LPS-induced models of fibroblast-like synoviocytes (FLSs) mimicking the inflammatory environment of KOA and activating NLRP3 inflammasome. FLSs treated with AGN (3 μM) resulted in a downregulation of HIF-1α and the components required for NLRP3 inflammasome activation. Meanwhile, the content of proinflammatory factors IL-1β and IL-18 in FLS supernatant was also reduced by AGN. In addition, both mRNA and protein levels of the fibrotic markers were significantly decreased after AGN management. To conclude, this study demonstrates that AGN alleviates synovitis and fibrosis in experimental KOA through the inhibition of HIF-1α accumulation and NLRP3 inflammasome activation. Additionally, not only does it reveal some novel targets for anti-inflammatory and antioxidant effects of AGN but also announces its potential value in treating KOA in humans.

scholarly journals Intra-articular Injection of Baicalein Inhibits Cartilage Catabolism and NLRP3 Inflammasome Signaling in a Posttraumatic OA Model

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hui Bai ◽  
Rui Yuan ◽  
Zhiheng Zhang ◽  
Lin Liu ◽  
Xinyu Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Rat Model ◽  
Nlrp3 Inflammasome ◽  
Type Ii Collagen ◽  
Cartilage Degeneration ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Nlrp3 Inflammasome Activation ◽  
Immunochemical Staining

Baicalein has been shown to have chondroprotective potential in vitro. However, its effect on disease modification in osteoarthritis (OA) is largely unknown. The present study is aimed at determining whether baicalein could slow the progression of OA and inhibit OA-related inflammation in a rat model of destabilization of the medial meniscus (DMM) and the underlying mechanisms. The rats subjected to DMM surgery were treated with baicalein (0.8, 1.6, and 3.2 μg/L, 50 μL, once a week) by intra-articular injection for 6 weeks. Dexamethasone (0.4 mg/mL, 50 μL, once a week) was used as a positive control. Histologic grading of cartilage degeneration was performed using the Osteoarthritis Research Society International (OARSI) recommended grading system (on a scale of 0-6). The expression levels of molecules associated with cartilage homeostasis and inflammatory cytokines were analyzed; moreover, the NLRP3 inflammasome activation and cartilage oxidative stress-associated molecules were determined. Baicalein treatment reduced the OARSI score and slowed OA disease progression in a dose-dependent manner within a certain range. Compared with DMM rats, intra-articular injection of baicalein led to (1) reduced levels of inflammatory mediates such as IL-1β and TNF-α, (2) reduced immunochemical staining of MMP-13 and ADAMTS-5, (3) suppressed immunochemical staining loss of type II collagen, (4) reduced expression of cartilage degradation markers including CTX-II and COMP in urine, and (5) inhibited NLRP3 inflammasome activation rather than regulated expression of SOD, GSH, and MDA. In contrast to the administration of baicalein, dexamethasone injection showed similar effects to slow OA progression, while dexamethasone inhibited NLRP3 inflammasome partly through decreasing levels of SOD, GSH, and MDA. This study indicated that baicalein may have the potential for OA prevention and exerts anti-inflammatory effects partly via suppressing NLRP3 inflammasome activation without affecting oxidative stress-associated molecules, and inhibition of cartilage catabolism enzymes in an OA rat model.

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