Inflammasomes are cytosolic protein complexes that respond to diverse danger signals by activating caspase-1. The sensor components of the inflammasome, often proteins of the nucleotide-binding oligomerization domain-like receptor (NLR) family, detect stress, danger stimuli, and pathogen-associated molecular patterns. We report that the eicosanoid 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2) and related cyclopentenone PGs inhibit caspase-1 activation by the NLR family leucine-rich repeat protein (NLRP)1 and NLRP3 inflammasomes. This inhibition was independent of the well-characterized role of 15d-PGJ2 as a peroxisome proliferator receptor-γ agonist, its activation of NF erythroid 2-related factor 2, or its anti-inflammatory function as an inhibitor of NF-κB. Instead, 15d-PGJ2 prevents the autoproteolytic activation of caspase-1 and the maturation of IL-1β through induction of a cellular state inhibitory to caspase-1 proteolytic function. The eicosanoid does not directly modify or inactivate the caspase-1 ...
The results presented in this study show that inflammasome formation and IL-1β processing is induced by hyperoxia in vivo and in vitro and is associated with increased alveolar epithelial protein permeability. Hyperoxia-stimulated K+ efflux, inflammasome formation, proinflammatory cytokine release, and marked induction of caspase-1 and IL-1β cleavage. The P2X7 agonist ATP enhanced hyperoxia-induced inflammasome activation, whereas the P2X7 antagonist, oxATP, inhibited hyperoxia-induced inflammasome activation. However, when ATP was scavenged with apyrase, hyperoxia-induced inflammasome activation was significantly decreased, indicating the possible involvement of the P2X7 receptor. Furthermore, shRNA silencing of inflammasome component expression abrogated hyperoxia-induced secretion of proinflammatory cytokines in vitro. These results suggest that hyperoxia induces K+ efflux through the P2X7 receptor and leads to inflammasome activation and secretion of proinflammatory cytokines.. Our studies ...
The hypothesis of this study was that sustained activity of the Nod-like receptor protein (NLRP)-3 inflammasome in wounds of diabetic humans and mice contributes to the persistent inflammatory response and impaired healing characteristic of these wounds. Macrophages (Mp) isolated from wounds on diabetic humans and db/db mice exhibited sustained inflammasome activity associated with low level of expression of endogenous inflammasome inhibitors. Soluble factors in the biochemical milieu of these wounds are sufficient to activate the inflammasome, as wound conditioned medium activates caspase-1 and induces release of IL-1β and IL-18 in cultured Mp via a reactive oxygen species-mediated pathway. Importantly, inhibiting inflammasome activity in wounds of db/db mice using topical application of pharmacological inhibitors improved healing of these wounds, induced a switch from pro-inflammatory to healing-associated Mp phenotypes and increased levels of pro-healing growth factors. Furthermore, data ...
To the Editor. We read the article of Osuka et al. (1) entitled "A Protective Role for Inflammasome Activation Following Injury" with great interest. However, we are concerned that the authors have not sufficiently ruled out the possibility that the major effects attributed to inflammasome inhibition were merely due to the solvent used.. The authors describe inflammasome activation in burned mice 1 day after injury as revealed by caspase 1 activation and increased interleukin 1β (IL-1β) production. Interestingly, the data suggest that inhibiting caspase 1 activity-and thereby inhibiting inflammasome activation-with the Ac-YVAD-cmk peptide did not reduce inflammation as expected. On the contrary, it caused a significantly higher mortality and increased expression of the proinflammatory cytokines IL-6 and IL-33 as compared with untreated burned mice. The authors therefore conclude that inflammasome activation might have a protective role following severe injury. Inhibition of (pro)caspase 1 ...
Chronic inflammation and inflammasome activation play roles in the pathogenesis of type 2 diabetes (2,29,30). NLRP3 is a member of the NLR family, which is responsible for cytosolic inflammasome activation. The NLRP3 inflammasome has been the focus of particular attention with regard to its roles in inflammatory responses, antimicrobial responses, and a variety of human diseases, including hereditary autoinflammatory syndromes, atherosclerosis, and diabetes (7,22,30,31). Recently, obesity-induced danger signals have been reported to activate the NLRP3 inflammasome and induce the production of IL-1β in adipose tissue in type 2 diabetic patients and mice fed a high-fat diet (9). Circulating levels of C-X-C motif chemokine 10 and CCL2, as well as interferon-γ mRNA and protein levels in adipose tissue, were significantly reduced in NLRP3-deficient mice, suggesting that the NLRP3 inflammasome plays a role in the macrophage-T-cell interactions that are associated with sustained levels of chronic ...
The NOD-like receptors (NLR) represent a major class of cytosolic pattern recognition receptors (PRR) that, like their cell-surface Toll-Like Receptor counterparts, are a central part of the innate immune response. There are more than 20 NLR family members, which recognize a wide variety of pathogen-associated molecular patterns (PAMPs). The pathogen specificity of many NLRs is not known, however, 3 of the NLRs form inflammasomes, protein complexes that activate immune and inflammatory responses. These complexes often activate pyroptosis, or caspase-1-dependent programmed cell death. Activation of any of 4 PRR family members (AIM2, NLRC4 or IPAF, NLRP1, and NLRP3) initiates the formation of an inflammasome. These protein complexes in turn activate caspase-1, leading to up-regulation of the pro-inflammatory cytokines IL1B and IL18. Other NLRs signal through RIP2, activating NFB signaling and ultimately cytokine release. As the inflammasomes were only recently identified, their mechanisms, as ...
Inflammatory responses play a key role in many neural pathologies, with localized signaling from the non-immune cells making critical contributions. The NLRP3 inflammasome is an important component of innate immune signaling and can link neural insult to chronic inflammation. The NLRP3 inflammasome requires two stages to contribute: priming and activation. The priming stage involves upregulation of inflammasome components while the activation stage results in the assembly and activation of the inflammasome complex. The priming step can be rate limiting and can connect insult to chronic inflammation, but our knowledge of the signals that regulate NLRP3 inflammasome priming in sterile inflammation is limited. This study examined the link between mechanical strain and inflammasome priming in neural systems. Transient non-ischemic elevation of intraocular pressure (IOP) increased mRNA for inflammasome components IL-1β, NLRP3, ASC and CASP1 in rat and mouse retinas. The elevation was greater one day after
Here, we demonstrate that HOIL-1L is specifically required for NLRP3 inflammasome-dependent IL-1β secretion in BMDMs independently of NF-κB activation. Mechanistically, the assembly of the NLRP3/ASC inflammasome and linear ubiquitination of the novel LUBAC substrate, ASC, both require HOIL-1L expression. The loss of these functions in HOIL-1L−/− mice results in resistance to MDP-induced peritonitis and contributes to survival upon LPS-induced systemic inflammation. This is the first demonstration that linear ubiquitination is required for NLRP3/ASC-dependent inflammasome activation, thus expanding the role of LUBAC as an innate immune regulator. This work is also the first to compare the role of HOIL-1L in MEF and macrophage cells. Our data indicate that HOIL-1L is critical for NF-κB activation in MEF cells, consistent with the literature (Fig. 1; Tokunaga et al., 2009; Gerlach et al., 2011; Ikeda et al., 2011). However, this activity is cell type specific because HOIL-1L is not required ...
The PYHIN family protein AIM2 is the only inflammasome sensor that does not belong to the NLR family, nevertheless some structural features are shared. AIM2 is characterized by the presence of an N‐terminal PYD and a C‐terminal HIN200 DNA‐binding domain. Since AIM2 lacks a CARD, it essentially requires, similar to NLRPs, the bridging protein ASC to recruit caspase‐1. Unlike other members of the PYHIN family, AIM2 is preferentially localized in the cytosol and operates as a direct intracellular sensor for cytosolic DNA (Fernandes‐Alnemri et al, 2009; Hornung et al, 2009). So far, no substantial prerequisites for its ligand DNA have been described (e.g. sequence motifs or nucleotide modifications), beside the DNA needs to be double stranded and of more than 80 bp in length to accomplish sufficient AIM2 inflammasome formation to allow caspase‐1 cleavage (Jin et al, 2012). Since AIM2 does not contain a NACHT domain, which could facilitate its multimerization, it was already initially ...
The ASC (apoptosis speck-like protein) is a key component of multimeric protein complexes that mediate inflammation and host defence. Comprising a PYD (Pyrin) domain and a CARD (caspase activation and recruitment domain), ASC functions downstream of NLRs (nucleotide-binding domain, leucine-rich repeat-containing receptors) and AIM2 (absent in melanoma 2) through the formation of supramolecular structures termed inflammasomes. However, the mechanism underlying ASC signalling and its dependency on oligomeric arrangements in inflammasome formation remain poorly understood. When expressed in cells, ASC forms discrete foci (called specks) typically with one speck per cell. We employed a BiFC (bimolecular fluorescence complementation) system to investigate and visualize ASC foci formation in living cells. We demonstrated that the CARD of ASC plays a central role in ASC inflammasome assembly, representing the minimal unit capable of forming foci in conjunction with the caspase 1 CARD. Mutational ...
Inflammasomes are high-molecular-weight cytosolic complexes that mediate the activation of caspases. There are many inflammasomes, and each is influenced by a unique pattern-recognition receptor response. Two signals are typically involved in the inflammasome pathways. Signal one involves recognition of pathogen-associated molecular patterns (PAMPs), such as LPS or other colonizing/invading microbes, that interact with TLRs, which induce the downstream production of pro-IL-1β. This is followed by signal two, which involves recognition of PAMPs or damage-associated molecular patterns (DAMPs), such as uric acid or ATP, via NLRP3, which leads to caspase-1-dependent cleavage of pro-IL-1β to active IL-1β and pyroptosis. Ultimately, these two signals cause the release of multiple proinflammatory cytokines. Both PAMPs and DAMPs can be liberated by early insults to the allograft, including ischemia/reperfusion injury, infections, and rejection. The consequence of inflammasome activation and IL-1 ...
Chronic low-grade inflammation is considered a driver of many age-related disorders, including vascular diseases (inflammaging). Inhibition of autophagic capacity with ageing was postulated to generate a pro-inflammatory condition via activation of inflammasomes, a group of Interleukin-1 activating intracellular multi-protein complexes. We thus investigated gene expression of inflammasome components in PBMC of 77 vascular patients (age 22-82) in association with age. Linear regression of real-time qRT-PCR data revealed a significant positive association of gene expression of each of the inflammasome components with age (Pearson correlation coefficients: AIM2: r = 0.245; P = 0.032; NLRP3: r = 0.367; P = 0.001; ASC (PYCARD): r = 0.252; P = 0.027; CASP1: r = 0.296; P = 0.009; CASP5: r = 0.453; P = 0.00003; IL1B: r = 0.247; P = 0.030). No difference in gene expression of AIM2, NLRP3, ASC CASP1, and CASP5 was detected between PBMC of patients with advanced atherosclerosis and other vascular patients, whereas
The NLRP3 (nucleotide-binding oligomerization domain-like receptor [NLR] family pyrin domain-containing 3) inflammasome is a member of the NLR family of innate immune cell sensors. These are crucial regulators of cytokine secretions, which promote ischemic cell death and insulin resistance. This review summarizes recent progress regarding the NLRP3 inflammasome as a potential treatment for ischemic stroke in patients with diabetes, two complicated diseases that often occur together. Stroke worsens glucose metabolism abnormalities, and the outcomes after stroke are more serious for diabetic patients compared with those without diabetes. Inflammation contributes to organ injury after ischemic stroke and diabetes. Recent research has focused on inhibiting the activation of inflammasomes and thus reducing the maturation of proinflammatory cytokines such as interleukin (IL)-1β and IL-18. Studies suggest that inhibition of NLRP3 prevents or alleviates both ischemic stroke and diabetes. Targeting against the
NLRP3 inflammasome assembly. CARD, caspase recruitment domain; LRR, leucine-rich repeat; NACHT/NBD, nucleotide binding domain; PYD, pyrin domain; CAP1, caspase-
INFLASOMES AND DISEASE PROCESSESA great many publications have focused on the roles of inflammasomes in various disease processes. Typical examples of these follow.1. Inflammasome and AtherosclerosisThe NLRP3 Inflammasome subtype links cholesterol crystals to the formation of atherosclerotic "vasculitis."Ref. NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals (2010) "The inflammatory nature of atherosclerosis is well established but the agent(s) that incite inflammation in the artery wall remain largely unknown. Germ-free animals are susceptible to atherosclerosis, suggesting that endogenous substances initiate the inflammation1. Mature atherosclerotic lesions contain macroscopic deposits of cholesterol crystals in the necrotic core, but their appearance late in atherogenesis had been thought to disqualify them as primary inflammatory stimuli. However, using a new microscopic technique, we revealed that minute cholesterol crystals are present in early ...
There is a clear need for interdisciplinary research and publications that bring together scientists who work on the inflammasome. This protein complex, termed the inflammasome and many of its components are implicated in disease disorders, autoimmune and infectious diseases. The structure, activation and regulation of the inflammasome complex have been and are still studied in increasing number of laboratories around the world. Our goal is to provide an issue summarizing every fascinating aspect of inflammasome activation and modulation of the innate immune response to microbial and to danger signals. This issue will bring the experts in inflammasome research up to speed with the most recent findings. However, several reviews are geared towards introducing the new scientists to the inflammasome complex and to the fundamental and essential information that will help them understand and even pursue their studies in this direction. By looking at the two sides of the coin, notably, some authors focused on
Exaggerated inflammasome activation in venous thrombosis in CD39-deficient mice. Extracellular release of ATP and ADP through cell death, injury, or activation is a potent stress response, altering the local microenvironment to activate paracrine and autocrine signaling pathways (18, 19). Binding of extracellular ATP to the plasma membrane receptor ionophore P2X7 activates a potent stress-response-signaling pathway characterized by potassium efflux, which triggers assembly and activity of the inflammasome, a multiprotein oligomer that activates highly proinflammatory cytokines including IL-1β (20). Gupta et al. recently reported increased NLRP3 inflammasome assembly in patients at high altitude at risk for DVT (21). Canonical inflammasome activation requires a "priming" step marked by NF-κB activation and inflammasome component transcription (20). A second signal initiates NLRP3-mediated assembly and oligomerization of inflammasome component fibers, proteolytic cleavage of pro-caspase-1 to ...
The term pyroptosis (pyro greek for fire or fever) has been originally coined to describe the non‐apoptotic, caspase‐1‐dependent cell death of Salmonella‐infected macrophages that would alarm and recruit neighboring cells to the site of infection (Cookson & Brennan, 2001). Later it became apparent that the activation of caspase‐1 to induce pyroptosis is controlled by a subset of PRRs that can induce inflammasome activation (e.g. NLRP3, AIM2 or NLRC4/NAIP). Upon recognition of their cognate ligands, these sensors seed the prion‐like assembly of the inflammasome adapter ASC into a high molecular weight cytosolic complex to which caspase‐1 becomes recruited and is activated by. Auto‐processed caspase‐1 then matures the cytokines IL‐1β and IL‐18 to render them bioactive and induce pyroptotic cell death. Besides this canonical inflammasome activation leading to caspase‐1 maturation, other pro‐inflammatory caspases, murine caspase‐11 and human caspase‐4 and caspase‐5, ...
The term pyroptosis (pyro greek for fire or fever) has been originally coined to describe the non‐apoptotic, caspase‐1‐dependent cell death of Salmonella‐infected macrophages that would alarm and recruit neighboring cells to the site of infection (Cookson & Brennan, 2001). Later it became apparent that the activation of caspase‐1 to induce pyroptosis is controlled by a subset of PRRs that can induce inflammasome activation (e.g. NLRP3, AIM2 or NLRC4/NAIP). Upon recognition of their cognate ligands, these sensors seed the prion‐like assembly of the inflammasome adapter ASC into a high molecular weight cytosolic complex to which caspase‐1 becomes recruited and is activated by. Auto‐processed caspase‐1 then matures the cytokines IL‐1β and IL‐18 to render them bioactive and induce pyroptotic cell death. Besides this canonical inflammasome activation leading to caspase‐1 maturation, other pro‐inflammatory caspases, murine caspase‐11 and human caspase‐4 and caspase‐5, ...
Deubiquitination of NLRP3 has been suggested to contribute to inflammasome activation, but the roles and molecular mechanisms are still unclear. We here demonstrate that ABRO1, a subunit of the BRISC deubiquitinase complex, is necessary for optimal NLRP3‐ASC complex formation, ASC oligomerization, caspase‐1 activation, and IL‐1β and IL‐18 production upon treatment with NLRP3 ligands after the priming step, indicating that efficient NLRP3 activation requires ABRO1. Moreover, we report that ABRO1 deficiency results in a remarkable attenuation in the syndrome severity of NLRP3‐associated inflammatory diseases, including MSU‐ and Alum‐induced peritonitis and LPS‐induced sepsis in mice. Mechanistic studies reveal that LPS priming induces ABRO1 binding to NLRP3 in an S194 phosphorylation‐dependent manner, subsequently recruiting the BRISC to remove K63‐linked ubiquitin chains of NLRP3 upon stimulation with activators. Furthermore, deficiency of BRCC3, the catalytically active ...
On September 21, 2017, Posted by Birgit Rogell , In Press Releases, With Kommentare deaktiviert für EMBL: Visualization of inflammasome formation in real life ...
Background: Inflammation is a key feature of aldosterone-induced vascular damage and dysfunction, but molecular mechanisms by which aldosterone triggers inflammation remain unclear. The NLRP3 inflammasome is a pivotal immune sensor that recognizes endogenous danger signals triggering sterile inflammation. Methods: We analyzed vascular function and inflammatory profile of wild-type (WT), NLRP3 knockout (NLRP3−/−), caspase-1 knockout (Casp-1−/−), and interleukin-1 receptor knockout (IL-1R−/−) mice treated with vehicle or aldosterone (600 µg·kg−1·d−1 for 14 days through osmotic mini-pump) while receiving 1% saline to drink. Results: Here, we show that NLRP3 inflammasome plays a central role in aldosterone-induced vascular dysfunction. Long-term infusion of aldosterone in mice resulted in elevation of plasma interleukin-1β levels and vascular abnormalities. Mice lacking the IL-1R or the inflammasome components NLRP3 and caspase-1 were protected from aldosterone-induced vascular ...
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The NOD-like receptors (NLR) are a family of intracellular sensors of microbial motifs and danger signals that have emerged as being crucial components of the innate immune responses and inflammation. Several NLRs (NALPs and IPAF) form a caspase-1-activating multiprotein complex, termed inflammasome, that processes proinflammatory cytokines including IL-1beta. Amongst the various inflammasomes, the NALP3 inflammasome is particularly qualified to sense a plethora of diverse molecules, ranging from bacterial muramyldipeptide to monosodium urate crystals. The important role of the NALP3 inflammasome is emphasized by the identification of mutations in the NALP3 gene that are associated with a susceptibility to inflammatory disorders. These and other issues related to the inflammasome are discussed in this review.
NALP3 is a component of the innate immune system that functions as a pattern recognition receptor (PRR) that recognizes pathogen-associated molecular patterns (PAMPs).[15] NALP3 belongs to the NOD-like receptor (NLR) subfamily of PRRs and NALP3 together with the adaptor ASC protein PYCARD forms a caspase-1 activating complex known as the NALP3 inflammasome. NALP3 in the absence of activating signal is kept in an inactive state complexed with HSP90 and SGT1 in the cytoplasm. NALP3 inflammasome detects danger signals such as crystalline uric acid and extracellular ATP released by damaged cells. These signals release HSP90 and SGT1 from and recruit ASC protein and caspase-1 to the inflammasome complex. Caspase-1 within the activated NALP3 inflammasome complex in turn activates the inflammatory cytokine, IL-1β.[15] The NALP3 inflammasome appears to be activated by changes in intracellular potassium caused by potassium efflux from mechanosensitive ion channels located in the cell membrane.[16] It ...
Inflammasomes are large protein complexes formed in response to cellular stresses that are platforms for recruitment and activation of caspase 1
Cellulose nanocrystal cationic derivative induces NLRP3 inflammasome-dependent IL-1β secretion associated with mitochondrial ROS production
Supplementary Material for: Inhibition of Rac1 Signaling Downregulates Inflammasome Activation and Attenuates Lung Injury in Neonatal Rats Exposed to Hyperoxia
As the sensor component of the NLRP9 inflammasome, plays a crucial role in innate immunity and inflammation. In response to pathogens, including rotavirus, initiates the formation of the inflammasome polymeric complex, made of NLRP9, PYCARD and CASP1. Recruitment of proCASP1 to the inflammasome promotes its activation and CASP1-catalyzed IL1B and IL18 maturation and release in the extracellular milieu. The active cytokines stimulate inflammatory responses. Inflammasomes can also induce pyroptosis, an inflammatory form of programmed cell death. NLRP9 inflammasome activation may be initiated by DHX9 interaction with viral double-stranded RNA (dsRNA), preferentially to short dsRNA segments.
Inflammation affects all stages of tumorigenesis. A key signaling pathway leading to acute and chronic inflammation is through activation of the caspase-1 inflammasome. Inflammasome complexes are assembled on activation of certain nucleotide-binding domain, leucine-rich repeat-containing proteins (NLR), AIM2-like receptors, or pyrin. Of these, NLRP1, NLRP3, NLRC4, NLRP6, and AIM2 influence the pathogenesis of cancer by modulating innate and adaptive immune responses, cell death, proliferation, and/or the gut microbiota. Activation of the inflammasome and IL18 signaling pathways is largely protective in colitis-associated colorectal cancer, whereas excessive inflammation driven by the inflammasome or the IL1 signaling pathways promotes breast cancer, fibrosarcoma, gastric carcinoma, and lung metastasis in a context-dependent manner. The clinical relevance of inflammasomes in multiple forms of cancer highlights their therapeutic promise as molecular targets. In this review, we explore the ...
Dying tumor cells release ATP, which activates the NLRP3 inflammasome in dendritic cells, enabling the secretion of interleukin-1β and the subsequent priming of tumor-specific interferon-γ-producing T lymphocytes. The therapeutic efficacy of anticancer chemotherapies may depend on dendritic cells (DCs), which present antigens from dying cancer cells to prime tumor-specific interferon-γ (IFN-γ)-producing T lymphocytes. Here we show that dying tumor cells release ATP, which then acts on P2X7 purinergic receptors from DCs and triggers the NOD-like receptor family, pyrin domain containing-3 protein (NLRP3)-dependent caspase-1 activation complex (inflammasome), allowing for the secretion of interleukin-1β (IL-1β). The priming of IFN-γ-producing CD8+ T cells by dying tumor cells fails in the absence of a functional IL-1 receptor 1 and in Nlpr3-deficient (Nlrp3−/−) or caspase-1-deficient (Casp-1−/−) mice unless exogenous IL-1β is provided. Accordingly, anticancer chemotherapy turned out to be
cAMP/EPAC Signaling Enables ETV2 to Induce Endothelial Cells with High Angiogenesis Potential The ETV2-induced endothelial cells obtained via cAMP signaling activation showed superior angiogenesis in vivo as well as in vitro. [Mol Ther] Abstract , Graphical Abstract Endothelial EphB4 Maintains Vascular Integrity and Transport Function in Adult Heart The authors showed that inducible and endothelial cell-specific inactivation of Ephb4 in adult mice was compatible with survival, but led to rupturing of cardiac capillaries, cardiomyocyte hypertrophy, and pathological cardiac remodeling. [eLIFE] Full Article Melatonin Inhibits Inflammasome-Associated Activation of Endothelium and Macrophages Attenuating Pulmonary Arterial Hypertension Melatonin attenuated inflammasome-associated vascular disorders by directly improving endothelial leakage and decreasing the formation of inflammasome multiprotein complexes in macrophages. [Cardiovasc Res] Abstract Coxsackievirus and Adenovirus Receptor Mediates the ...
Recent study of the CAPS disease spectrum has led to significant advances in our understanding of the NLRP3 inflammasome and IL-1β-mediated inflammation. While translational studies have resulted in vital therapies for patients with CAPS, many questions about the inflammasome and other caspase-1-dependent pathways remain. Inflammasome-mediated IL-18 has largely been overlooked in the context of human disease. In addition, recent studies have demonstrated caspase-1 and inflammasome functions extending beyond cytokine maturation to cellular death pathways, but whether these processes have any bearing on CAPS remains to be seen. Here, we take advantage of mutant NLRP3 knockin mouse lines to investigate these questions.. Our studies demonstrate that dysregulated IL-18 secretion occurs from both patient and Nlrp3 mutant mouse cells in a manner similar to IL-1β. In vitro, a hallmark of CAPS is lack of reliance on the 2-signal paradigm generally required for secretion of active IL-1β. We used this ...
In the current issue of Circulation Research, Folco et al24 suggest a novel link between hypoxia, inflammasome activation, and induction of the macrophage IL-1β response. To gain a holistic understanding of IL-1β production under hypoxic conditions, Folco et al interrogated the effect of moderate hypoxia in human macrophages and plaques at several levels of regulation, including transcription, pro-IL-1β processing, and inflammasome activation. First, they make the interesting observation that hypoxia synergistically elevates lipopolysaccharide-induced pro-IL-1β levels in a manner independent of transcription. Follow-up pulse-chase experiments confirmed slower pro-IL-1β degradation under hypoxia, an observation that implicates either proteasomal or autophagic dysfunction. Several prior reports have suggested a complex role for autophagy in IL-1β production. Autophagy can both facilitate the degradation of pro-IL-1β25 and dampen the ability of the NLRP3 inflammasome to convert pro-IL-1β to ...
Induction of the inflammasome protein cryopyrin (NLRP3) in visceral adipose tissue (VAT) promotes release of the proinflammatory cytokine IL-1β in obesity. Although this mechanism contributes to peripheral metabolic dysfunction, effects on the brain remain unexplored. We investigated whether visceral adipose NLRP3 impairs cognition by activating microglial IL-1 receptor 1 (IL-1R1). After observing protection against obesity-induced neuroinflammation and cognitive impairment in NLRP3-KO mice, we transplanted VAT from obese WT or NLRP3-KO donors into lean recipient mice. Transplantation of VAT from a WT donor (TRANSWT) increased hippocampal IL-1β and impaired cognition, but VAT transplants from comparably obese NLRP3-KO donors (TRANSKO) had no effect. Visceral adipose NLRP3 was required for deficits in long-term potentiation (LTP) in transplant recipients, and LTP impairment in TRANSWT mice was IL-1 dependent. Flow cytometric and gene expression analyses revealed that VAT transplantation ...
Induction of the inflammasome protein cryopyrin (NLRP3) in visceral adipose tissue (VAT) promotes release of the pro-inflammatory cytokine interleukin-1β (IL1β) in obesity. While this mechanism contributes to peripheral metabolic dysfunction, effects on the brain remain unexplored. These studies investigated whether visceral adipose NLRP3 impairs cognition by activating microglial interleukin-1 receptor 1 (IL1R1). After observing protection against obesity-induced neuroinflammation and cognitive impairment in NLRP3KO mice, we transplanted VAT from obese WT or NLRP3KO donors into lean recipients. Transplantation of VAT from a WT donor (TRANSWT) increased hippocampal IL1β and impaired cognition, but VAT transplants from comparably obese NLRP3KO donors (TRANSKO) had no effect. Visceral adipose NLRP3 was required for deficits in long-term potentiation (LTP) in transplant recipients, and LTP impairment in TRANSWT mice was IL1-dependent. Flow cytometric and gene expression analyses revealed that ...
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Formation of the inflammasome results in the activation of multiple pathways responsible for co-ordinating our immune response, yet interestingly, there are multiple forms of inflammasomes made up and triggered by different sets of proteins. This initial step of activation has been covered very well before, here. The activated inflammsome goes on to trigger key downstream members of our innate immune system through the recruitment of an important regulatory protease (it cuts up other proteins) - caspase 1, which converts inactive molecules to active, pro-inflammatory ones, such as interleukin-1 beta and interleukin-18. This inflammatory cascade functions to initiate an effective local and systemic immune response through the control of the innate and adaptive immune system; for example, IL-beta is responsible for fever and the recruitment of immune cells to the site of infection, and IL-18 induces the development of key T cell responses ...
Despite the recognized role of inflammation in cardiovascular diseases including atherosclerosis, this role may not be an initiating or essential mechanism in a...
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Abstract:The connection between the innate immune system, clock genes, and mitochondrial bioenergetics was analyzed during aging and sepsis in mouse heart. Our results suggest that the sole NF-κB activation does not explain the inflammatory process underlying aging; the former also triggers the NLRP
Sigma-Aldrich offers abstracts and full-text articles by [Ying Yang, Dong-Mei Zhang, Jia-Hui Liu, Lin-Shui Hu, Qiao-Chu Xue, Xiao-Qin Ding, Ling-Dong Kong].
This rat study demonstrated that opioids can actually cause chronic pain rather than treating it. In rats, anyway. Obviously replication in human studies is…
Our results suggest that PVCs may be therapeutically useful for the treatment of macrophage- and inflammation-mediated diseases by paracrine action via the secretion of various biological factors.
Pyroptosis is a form of lytic programmed cell death initiated by inflammasomes, which detect cytosolic contamination or perturbation. This drives activation of caspase-1 or caspase-11/4/5, which cleave gasdermin D, separating its N-terminal pore-forming domain (PFD) from the C-terminal repressor dom …
Pyroptosis is a form of necrotic and inflammatory programmed cell death induced by inflammatory caspases, one of which is activated by Inflammasome, a multiprotein oligomer responsible for the activation of inflammatory responses. Discover the latest research on inflammasome and pyroptosis here. ...
A major focus of our lab is to understand how the immune system distinguishes between virulent and avirulent bacteria and tailors appropriate antimicrobial responses. One key immune pathway involves the inflammasome, a multi-protein cytosolic complex that activates the host proteases caspase-1 and caspase-11 upon cytosolic detection of bacterial products. These caspases mediate the release of IL-1 family cytokines and other inflammatory factors critical for host defense, but overexuberant activation can lead to pathological outcomes such as septic shock. We are currently pursuing how mouse and human inflammasomes differentially respond to bacterial infection ...
February 13, 2018. The assembly of the NLRP3 inflammasome can promote the release of IL-1β/IL-18 and initiate pyroptosis. Accordingly, the dysregulation of NLRP3 inflammasome activation is involved in a variety of... ...
Dhar, Poshmaal, Sarkar, Sohinee, Ng, Garrett Z, Kalitsis, Paul, Saeed, Muhammad A, McGuckin, Michael A, Ellis, Justine A and Sutton, Philip 2019, Effect of MUC1 length polymorphisms on the NLRP3 inflammasome response of human macrophages, Human immunology, vol. 80, no. 10, pp. 878-882, doi: 10.1016/j.humimm.2019.06.001. ...
The aim of our research is to understand how host cells recognize the presence of bacterial pathogens and how they eliminate this threat. We focus on the initial contact between host and pathogen, during which host defense mainly relies on the innate immune system. The major area of research in the lab is the study of inflammasome complexes, which are assembled by cytosolic pattern recognition receptors in response to pathogens.. Keywords: Innate immunity / inflammasome / host-pathogen interaction / cell signaling / Salmonella. Subject area(s): Immunology , Microbiology, Virology & Pathogens , Signal Transduction. ...