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Dengue virus (DENV) is a medically important flavivirus causing an estimated 50-100 million dengue cases annually, some of whom progress to severe disease. DENV non-structural protein 1 (NS1) is secreted from infected cells and has been implicated as a major driver of dengue pathogenesis by inducing endothelial barrier dysfunction. However, less is known about how DENV NS1 interacts with immune cells and what role these interactions play. Here we report that DENV NS1 can trigger activation of inflammasomes, a family of cytosolic innate immune sensors that respond to infectious and noxious stimuli, in mouse and human macrophages. DENV NS1 induces the release of IL-1β in a caspase-1 dependent manner. Additionally, we find that DENV NS1-induced inflammasome activation is independent of the NLRP3, Pyrin, and AIM2 inflammasome pathways, but requires CD14. Intriguingly, DENV NS1-induced inflammasome activation does not induce pyroptosis and rapid cell death; instead, macrophages maintain cellular viability while releasing IL-1β. Lastly, we show that caspase-1/11-deficient, but not NLRP3-deficient, mice are more susceptible to lethal DENV infection. Together, these results indicate that the inflammasome pathway acts as a sensor of DENV NS1 and plays a protective role during infection.

BACKGROUND: Oxidized phospholipids play a key role in the atherogenic potential of lipoprotein(a) (Lp[a]); however, Lp(a) is a complex particle that warrants research into additional proinflammatory mediators. We hypothesized that additional Lp(a)-associated lipids contribute to the atherogenicity of Lp(a). METHODS: Untargeted lipidomics was performed on plasma and isolated lipoprotein fractions. The atherogenicity of the observed Lp(a)-associated lipids was tested ex vivo in primary human monocytes by RNA sequencing, ELISA, Western blot, and transendothelial migratory assays. Using immunofluorescence staining and single-cell RNA sequencing, the phenotype of macrophages was investigated in human atherosclerotic lesions. RESULTS: Compared with healthy individuals with low/normal Lp(a) levels (median, 7 mg/dL [18 nmol/L]; n=13), individuals with elevated Lp(a) levels (median, 87 mg/dL [218 nmol/L]; n=12) demonstrated an increase in lipid species, particularly diacylglycerols (DGs) and lysophosphatidic acid (LPA). DG and the LPA precursor lysophosphatidylcholine were enriched in the Lp(a) fraction. Ex vivo stimulation with DG(40:6) demonstrated a significant upregulation in proinflammatory pathways related to leukocyte migration, chemotaxis, NF-κB (nuclear factor kappa B) signaling, and cytokine production. Functional assessment showed a dose-dependent increase in the secretion of IL (interleukin)-6, IL-8, and IL-1β after DG(40:6) and DG(38:4) stimulation, which was, in part, mediated via the NLRP3 (NOD [nucleotide-binding oligomerization domain]-like receptor family pyrin domain containing 3) inflammasome. Conversely, LPA-stimulated monocytes did not exhibit an inflammatory phenotype. Furthermore, activation of monocytes by DGs and LPA increased their transendothelial migratory capacity. Human atherosclerotic plaques from patients with high Lp(a) levels demonstrated colocalization of Lp(a) with M1 macrophages, and an enrichment of CD68+IL-18+TLR4+ (toll-like receptor) TREM2+ (triggering receptor expressed on myeloid cells) resident macrophages and CD68+CASP1+ (caspase) IL-1B+SELL+ (selectin L) inflammatory macrophages compared with patients with low Lp(a). Finally, potent Lp(a)-lowering treatment (pelacarsen) resulted in a reduction in specific circulating DG lipid subspecies in patients with cardiovascular disease with elevated Lp(a) levels (median, 82 mg/dL [205 nmol/L]). CONCLUSIONS: Lp(a)-associated DGs and LPA have a potential role in Lp(a)-induced monocyte inflammation by increasing cytokine secretion and monocyte transendothelial migration. This DG-induced inflammation is, in part, NLRP3 inflammasome dependent.

From studies of individual families to global collaborative efforts, the NLRP3 inflammasome is now recognized to be a key regulator of innate immunity. Activated by a panoply of pathogen-associated and endogenous triggers, NLRP3 serves as an intracellular sensor that drives carefully coordinated assembly of the inflammasome, and downstream inflammation mediated by IL-1 and IL-18. Initially discovered as the cause of the autoinflammatory spectrum of cryopyrin-associated periodic syndrome (CAPS), NLRP3 is now also known to play a role in more common diseases including cardiovascular disease, gout, and liver disease. We have seen cohesion in results from clinical studies in CAPS patients, ex vivo studies of human cells and murine cells, and in vivo murine models leading to our understanding of the downstream pathways, cytokine secretion, and cell death pathways that has solidified the role of autoinflammation in the pathogenesis of human disease. Recent advances in our understanding of the structure of the inflammasome have provided ways for us to visualize normal and mutant protein function and pharmacologic inhibition. The subsequent development of targeted therapies successfully used in the treatment of patients with CAPS completes the bench to bedside translational loop which has defined the study of this unique protein.

Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1β production is detrimental during Salmonella infection. Mice lacking IL-1β (IL-1β -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid (SCFA)-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1β -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1β induces expression of complement anaphylatoxins and suppresses the complement-inactivator carboxypeptidase N (CPN1). Disrupting this process via IL-1β loss prevented mortality in Salmonella-infected IL-1β -/- mice. Finally, we found that IL-1β expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1β signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1β signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.

Atherosclerosis is a chronic inflammatory condition of the arteries and represents the primary cause of various cardiovascular diseases. Despite ongoing progress, finding effective anti-inflammatory therapeutic strategies for atherosclerosis remains a challenge. Here, we assessed the potential of molecular magnetic resonance imaging (MRI) to visualize the effects of 01BSUR, an anti-interleukin-1β monoclonal antibody, for treating atherosclerosis in a murine model. Male apolipoprotein E-deficient mice were divided into a therapy group (01BSUR, 2 × 0.3 mg/kg subcutaneously, n = 10) and control group (no treatment, n = 10) and received a high-fat diet for eight weeks. The plaque burden was assessed using an elastin-targeted gadolinium-based contrast probe (0.2 mmol/kg intravenously) on a 3 T MRI scanner. T1-weighted imaging showed a significantly lower contrast-to-noise (CNR) ratio in the 01BSUR group (pre: 3.93042664; post: 8.4007067) compared to the control group (pre: 3.70679168; post: 13.2982156) following administration of the elastin-specific MRI probe (p < 0.05). Histological examinations demonstrated a significant reduction in plaque size (p < 0.05) and a significant decrease in plaque elastin content (p < 0.05) in the treatment group compared to control animals. This study demonstrated that 01BSUR hinders the progression of atherosclerosis in a mouse model. Using an elastin-targeted MRI probe, we could quantify these therapeutic effects in MRI. [ABSTRACT FROM AUTHOR]

Background: Neurogenic meningeal inflammation is regarded as a key driver of migraine headache. Multiple evidence show importance of inflammatory processes in the dura mater for pain generation but contribution of the leptomeninges is less clear. We assessed effects of cortical spreading depolarization (CSD), the pathophysiological mechanism of migraine aura, on expression of inflammatory mediators in the leptomeninges. Methods: A single CSD event was produced by a focal unilateral microdamage of the cortex in freely behaving rats. Three hours later intact cortical leptomeninges and parenchyma of ipsi-lesional (invaded by CSD) and sham-treated contra-lesional (unaffected by CSD) hemispheres were collected and mRNA levels of genes associated with inflammation (Il1b, Tnf, Ccl2; Cx3cl1, Zc3h12a) and endocannabinoid CB2 receptors (Cnr2) were measured using qPCR. Results: Three hours after a single unilateral CSD, most inflammatory factors changed their expression levels in the leptomeninges, mainly on the side of CSD. The meninges overlying affected cortex increased mRNA expression of all proinflammatory cytokines (Il1b, Tnf, Ccl2) and anti-inflammatory factors Zc3h12a and Cx3cl1. Upregulation of proinflammatory cytokines was found in both meninges and parenchyma while anti-inflammatory markers increased only meningeal expression. Conclusion: A single CSD is sufficient to produce pronounced leptomeningeal inflammation that lasts for at least three hours and involves mostly meninges overlying the cortex affected by CSD. The prolonged post-CSD inflammation of the leptomeninges can contribute to mechanisms of headache generation following aura phase of migraine attack. [ABSTRACT FROM AUTHOR]

Peripheral cytokines may influence psychoemotional behavior, but the role of interleukin-1beta (IL-1beta) in altering anxiety and motor activity in response to inflammatory activation remains unclear. To clarify this issue, correlations between behavioral parameters in the elevated plus maze (EPM) test and plasma levels of IL-1beta after administration of the proinflammatory stimulus lipopolysaccharide (LPS) in different modes were analyzed in adult male rats. LPS in doses of 0.5 or 5 mg/kg, as well as physiological solution (control), were administered to rats intraperitoneally. The most pronounced behavioral effect 24 hours after a single injection was an endotoxin dose-dependent inhibition of the animals' motor activity. Twenty four hours after the 5 mg/kg, an increased anxiety behavior was also observed. The behavioral changes caused by the high dose of endotoxin were completely normalized after a week. The behavior of the animals one day after the end of repeated injections of LPS at a lower dose for a week (0.5 mg/kg; once every two days) also did not differ from the control. The inhibition of motor activity after LPS could be due to an increase in the level of IL-1beta in the blood plasma, as indicated by the identified significant negative correlations between IL-1beta and the corresponding behavioral parameters. No significant correlation was found between the peripheral level of IL-1beta and such a classic indicator of anxiety as the percentage of entries into the open arms of the maze. In general, the obtained results allow us to conclude that IL-1beta is an undoubted participant in the mechanism of the transient inhibitory effect of LPS on motor activity. [ABSTRACT FROM AUTHOR]

The abuse of methamphetamine is a significant threat to cardiovascular health and has detrimental effects on the myocardium. The present study aims to explore potential interventions that can mitigate myocardial pyroptosis in rats following methamphetamine withdrawal. A total of 104 male Wistar rats were randomly assigned to eight groups. The rats underwent a methamphetamine administration protocol, receiving intraperitoneal injections of 10 mg/kg during the 1st week, followed by a weekly dose escalation of 1 mg/kg from the second to the 6th week and two times per day. Concurrently, the rats engaged in 6 weeks of moderate-intensity treadmill aerobic training, lasting 60 min per day, 5 days a week. Simultaneously, the Nutrition bio-shield Superfood (NBS) supplement was administered at a dosage of 25 g/kg daily for 6 weeks. The study assessed the expression levels of Caspase-1, Interleukin-1beta (IL-1β), and Interleukin-18 (IL-18) genes in myocardial tissue. Data analysis utilized a one-way analysis of variance (p ≤ 0.05). The findings revealed that methamphetamine usage significantly elevated the expression of Caspase-1, IL-1β, and IL-18 genes (p ≤ 0.05). Conversely, methamphetamine withdrawal led to a notable reduction in the expression of these genes (p ≤ 0.05). Noteworthy reductions in Caspase-1, IL-1β, and IL-18 expression were observed following aerobic training, supplementation, and the combined approach (p ≤ 0.05). The chronic use of methamphetamine was associated with cardiac tissue damage. This study highlights the potential of aerobic training and NBS Superfood supplementation in mitigating the harmful effects of methamphetamine-induced myocardial pyroptosis. The observed reductions in gene expression levels indicate promising interventions to address the cardiovascular consequences of methamphetamine abuse. The findings of this study suggest that a combination of aerobic exercise and NBS Superfood supplementation can provide a promising approach to mitigate the deleterious effects of methamphetamine on the heart. These findings can be useful for healthcare professionals and policymakers to design effective interventions to prevent and manage the adverse effects of methamphetamine abuse. [ABSTRACT FROM AUTHOR]

Abstract Atherosclerosis is a chronic inflammatory condition of the arteries and represents the primary cause of various cardiovascular diseases. Despite ongoing progress, finding effective anti-inflammatory therapeutic strategies for atherosclerosis remains a challenge. Here, we assessed the potential of molecular magnetic resonance imaging (MRI) to visualize the effects of 01BSUR, an anti-interleukin-1β monoclonal antibody, for treating atherosclerosis in a murine model. Male apolipoprotein E-deficient mice were divided into a therapy group (01BSUR, 2 × 0.3 mg/kg subcutaneously, n = 10) and control group (no treatment, n = 10) and received a high-fat diet for eight weeks. The plaque burden was assessed using an elastin-targeted gadolinium-based contrast probe (0.2 mmol/kg intravenously) on a 3 T MRI scanner. T1-weighted imaging showed a significantly lower contrast-to-noise (CNR) ratio in the 01BSUR group (pre: 3.93042664; post: 8.4007067) compared to the control group (pre: 3.70679168; post: 13.2982156) following administration of the elastin-specific MRI probe (p

In the past decade, targeted therapies for solid tumors, including non-small cell lung cancer (NSCLC), have advanced significantly, offering tailored treatment options for patients. However, individuals without targetable mutations pose a clinical challenge, as they may not respond to standard treatments like immune-checkpoint inhibitors (ICIs) and novel targeted therapies. While the mechanism of action of ICIs seems promising, the lack of a robust response limits their widespread use. Although the expression levels of programmed death ligand 1 (PD-L1) on tumor cells are used to predict ICI response, identifying new biomarkers, particularly those associated with the tumor microenvironment (TME), is crucial to address this unmet need. Recently, inflammatory cytokines such as interleukin-1 beta (IL-1β) have emerged as a key area of focus and hold significant potential implications for future clinical practice. Combinatorial approaches of IL-1β inhibitors and ICIs may provide a potential therapeutic modality for NSCLC patients without targetable mutations. Recent advancements in our understanding of the intricate relationship between inflammation and oncogenesis, particularly involving the IL-1β/PD-1/PD-L1 pathway, have shed light on their application in lung cancer development and clinical outcomes of patients. Targeting these pathways in cancers like NSCLC holds immense potential to revolutionize cancer treatment, particularly for patients lacking targetable genetic mutations. However, despite these promising prospects, there remain certain aspects of this pathway that require further investigation, particularly regarding treatment resistance. Therefore, the objective of this review is to delve into the role of IL-1β in NSCLC, its participation in inflammatory pathways, and its intricate crosstalk with the PD-1/PD-L1 pathway. Additionally, we aim to explore the potential of IL-1β as a therapeutic target for NSCLC treatment.

Objective To investigate the expression levels of nerve injury-induced protein 1 (Ninjl), interleukin-1β(IL-1β), and protein gene product 9.5 (PGP-9.5) in the ectopic endometrial tissues of patients with endometriosis (EMT) and their relationship with dysmenorrhea. Methods Ectopic endometrial tissues from 40 patients with ovarian EMT diagnosed by post-ope-rative gynecological pathological examination in our hospital from April 2020 to April 2021 were selected as group A. In situ endo-metrial tissues from 20 of these patients were obtained as group B. Normal endometrial tissues from 20 patients with uterine fi-broids in the same period were collected as group C. Group A was divided into a dysmenorrhoea subgroup and a non-dysmenorrhoea subgroup according to the presence or absence of dysmenorrhoea, with 20 patients per subgroup. The expression levels of Ninj1, IL-1β, and PGP-9.5 in the endometrial tissues of groups A, B, and C were measured by immunohistochemistry, and their correlation was analyzed. The expression level of IL-1β in the peripheral blood of patiens in groups A and C was measured by enzyme-linked immunosorbent assay. Results The expression level of IL-1β in the peripheral blood of patients in group A was signifi-cantly higher than that in group C (t=-4.184,P

Abstract Background Glomus Tumor (GT) are benign neoplasms that originate from mesenchymal cells. It presents as tenderness and cold allodynia in the digits, especially in the subungual region. There are a few studies that investigated the mechanism of pain. Objectives To analyze the clinical-pathologic characteristics of GT and to identify the expression of IL-1β, IL-6, and CGRP in it, further, to explore the possible mechanism of pain. Methods The clinical and pathological data of 60 GT patients were retrospectively analyzed. Tissue microarrays and immunohistochemistry were used to measure the expression of IL-1β, IL-6 and CGRP. Results GT is more common in females and the ratio of male to was near to 1:2, mostly in middle-aged people. It often occurs in fingertips, especially the thumbs. Patients often present with spontaneous pain, tenderness, and cold hypersensitivity. Both the two pain mediators IL-1β and IL-6 were highly expressed in GT cells of patients with and without cold hypersensitivity. While CGRP was not expressed in GT. Study limitations Low sample size and further research is needed to explore the specific mechanism. Conclusions IL-1β and IL-6 were highly expressed in GT cells, suggesting that IL-1β and IL-6 have certain nociceptive roles in GT. In the 4 patients with cold intolerance, the intensity of IL-1β and IL-6 staining was also strong, suggesting that they may not play a role in the cold hypersensitivity. However, since there are only 4 patients with cold intolerance, it’s necessary to conduct further in-depth research using a larger sample size. The specific role of CGRP in GT has not been found yet.

ObjectiveIn gout, hyperuricemia promotes urate crystal deposition, which stimulates the NLRP3 inflammasome and interleukin-1β (IL-1β)-mediated arthritis. Incident gout without background hyperuricemia is rarely reported. To identify hyperuricemia-independent mechanisms driving gout incidence and progression, we characterized erosive urate crystalline inflammatory arthritis in a young female patient with normouricemia diagnosed as having sufficient and weighted classification criteria for gout according to the American College of Rheumatology (ACR)/EULAR gout classification criteria (the proband).MethodsWe conducted whole-genome sequencing, quantitative proteomics, whole-blood RNA-sequencing analysis using serum samples from the proband. We used a mouse model of IL-1β-induced knee synovitis to characterize proband candidate genes, biomarkers, and pathogenic mechanisms of gout.ResultsLubricin level was attenuated in human proband serum and associated with elevated acute-phase reactants and inflammatory whole-blood transcripts and transcriptional pathways. The proband had predicted damaging gene variants of NLRP3 and of inter-α trypsin inhibitor heavy chain 3, an inhibitor of lubricin-degrading cathepsin G. Changes in the proband's serum protein interactome network supported enhanced lubricin degradation, with cathepsin G activity increased relative to its inhibitors, SERPINB6 and thrombospondin 1. Activation of Toll-like receptor 2 (TLR-2) suppressed levels of lubricin mRNA and lubricin release in cultured human synovial fibroblasts (P

Background Hepatic steatosis, which involves the excessive accumulation of lipid droplets in hepatocytes, presents a significant global health concern due to its association with obesity and metabolic disorders. Inflammation plays a crucial role in the progression of hepatic steatosis; however, the precise molecular mechanisms responsible for this process remain unknown. Methods This study investigated the involvement of the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3) inflammasome and the forkhead box O6 (FoxO6) transcription factor in the pathogenesis of hepatic steatosis. We monitored the NLRP3 inflammasome and lipogenesis in mice overexpressing the constitutively active (CA)-FoxO6 allele and FoxO6-null mice. In an in vitro study, we administered palmitate to liver cells overexpressing CA-FoxO6 and measured changes in lipid metabolism. Results We administered palmitate treatment to clarify the mechanisms through which FoxO6 activates cytokine interleukin (IL)-1β through the NLRP3 inflammasome. The initial experiments revealed that dephosphorylation led to palmitate-induced FoxO6 transcriptional activity. Further palmitate experiments showed increased expression of IL-1β and the hepatic NLRP3 inflammasome complex, including adaptor protein apoptotic speck protein containing a caspase recruitment domain (ASC) and pro-caspase-1. Furthermore, thioredoxin-interacting protein (TXNIP), a key regulator of cellular redox conditions upstream of the NLRP3 inflammasome, was induced by FoxO6 in the liver and HepG2 cells. Conclusion The findings of this study shed light on the molecular mechanisms underpinning the FoxO6-NLRP3 inflammasome axis in promoting inflammation and lipid accumulation in the liver.

Abstract Background: Only a fraction of patients with cutaneous lupus erythematosus (CLE) will eventually progress toward systemic disease (SLE). Objective: To find inflammatory biomarkers which could predict the progression of cutaneous lupus erythematosus (CLE) into systemic lupus erythematosus (SLE) using immunohistochemical (IHC) assays. Methods: Immunohistochemical markers for cytotoxic, inflammatory, and anti-inflammatory responses and morphometric methods were applied to routine paraffin sections of skin biopsies, taken from lesions of 59 patients with discoid lupus, subacute lupus, and lupus tumidus. For the diagnosis of SLE, patients were classified by both the American College of Rheumatology (ACR-82) and the Systemic Lupus International Collaborating Clinics (SLICC-12) systems. Results: Skin samples from CLE/SLE +patients presented higher expression of IL-1β (ARC-82: p = 0.024; SLICC-12: p = 0.0143) and a significantly higher number of cells marked with granzyme B and perforin (ARC: p = 0.0097; SLICC-12: p = 0.0148). Biopsies from CLE/SLE- individuals had higher expression of IL-17 (ARC-82: p = 0.0003; SLICC-12: p = 0.0351) and presented a positive correlation between the density of granzyme A+and FoxP3+ cells (ARC-82: p = 0.0257; SLICC-12: p = 0.0285) and CD8+ cells (ARC-82: p = 0.0075; SLICC-12: p = 0.0102), as well as between granulysin-positive and CD8+ cells (ARC-82: p = 0.0024; SLICC-12: p = 0.0116). Study limitations: Patients were evaluated at a specific point in their evolution and according to the presence or not of systemic disease. The authors cannot predict how many more, from each group, would have evolved towards SLE in the following years. Conclusions: In this cohort, immunohistochemical findings suggested that patients with a tendency to systemic disease will show strong reactivity for IL-1β, while those with purely cutaneous involvement will tend to express IL-17 more intensely.

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The tumor microenvironment (TME) consists of cancer cells surrounded by stromal components including tumor vessels. Transforming growth factor‐β (TGF‐β) promotes tumor progression by inducing epithelial–mesenchymal transition (EMT) in cancer cells and stimulating tumor angiogenesis in the tumor stroma. We previously developed an Fc chimeric TGF‐β receptor containing both TGF‐β type I (TβRI) and type II (TβRII) receptors (TβRI‐TβRII‐Fc), which trapped all TGF‐β isoforms and suppressed tumor growth. However, the precise mechanisms underlying this action have not yet been elucidated. In the present study, we showed that the recombinant TβRI‐TβRII‐Fc protein effectively suppressed in vitro EMT of oral cancer cells and in vivo tumor growth in a human oral cancer cell xenograft mouse model. Tumor cell proliferation and angiogenesis were suppressed in tumors treated with TβRI‐TβRII‐Fc. Molecular profiling of human cancer cells and mouse stroma revealed that K‐Ras signaling and angiogenesis were suppressed. Administration of TβRI‐TβRII‐Fc protein decreased the expression of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF), interleukin‐1β (IL‐1β) and epiregulin (EREG) in the TME of oral cancer tumor xenografts. HB‐EGF increased proliferation of human oral cancer cells and mouse endothelial cells by activating ERK1/2 phosphorylation. HB‐EGF also promoted oral cancer cell‐derived tumor formation by enhancing cancer cell proliferation and tumor angiogenesis. In addition, increased expressions of IL‐1β and EREG in oral cancer cells significantly enhanced tumor formation. These results suggest that TGF‐β signaling in the TME controls cancer cell proliferation and angiogenesis by activating HB‐EGF/IL‐1β/EREG pathways and that TβRI‐TβRII‐Fc protein is a promising tool for targeting the TME networks. [ABSTRACT FROM AUTHOR]

BackgroundSalt sensitivity of blood pressure is an independent predictor of cardiovascular morbidity and mortality. The exact mechanism by which salt intake increases blood pressure and cardiovascular risk is unknown. We previously found that sodium entry into antigen-presenting cells (APCs) via the amiloride-sensitive epithelial sodium channel EnaC (epithelial sodium channel) leads to the formation of IsoLGs (isolevuglandins) and release of proinflammatory cytokines to activate T cells and modulate salt-sensitive hypertension. In the current study, we hypothesized that ENaC-dependent entry of sodium into APCs activates the NLRP3 (NOD [nucleotide-binding and oligomerization domain]-like receptor family pyrin domain containing 3) inflammasome via IsoLG formation leading to salt-sensitive hypertension.MethodsWe performed RNA sequencing on human monocytes treated with elevated sodium in vitro and Cellular Indexing of Transcriptomes and Epitopes by Sequencing analysis of peripheral blood mononuclear cells from participants rigorously phenotyped for salt sensitivity of blood pressure using an established inpatient protocol. To determine mechanisms, we analyzed inflammasome activation in mouse models of deoxycorticosterone acetate salt-induced hypertension as well as salt-sensitive mice with ENaC inhibition or expression, IsoLG scavenging, and adoptive transfer of wild-type dendritic cells into NLRP3 deficient mice.ResultsWe found that high levels of salt exposure upregulates the NLRP3 inflammasome, pyroptotic and apoptotic caspases, and IL (interleukin)-1β transcription in human monocytes. Cellular Indexing of Transcriptomes and Epitopes by Sequencing revealed that components of the NLRP3 inflammasome and activation marker IL-1β dynamically vary with changes in salt loading/depletion. Mechanistically, we found that sodium-induced activation of the NLRP3 inflammasome is ENaC and IsoLG dependent. NLRP3 deficient mice develop a blunted hypertensive response to elevated sodium, and this is restored by the adoptive transfer of NLRP3 replete APCs.ConclusionsThese findings reveal a mechanistic link between ENaC, inflammation, and salt-sensitive hypertension involving NLRP3 inflammasome activation in APCs. APC activation via the NLRP3 inflammasome can serve as a potential diagnostic biomarker for salt sensitivity of blood pressure.

Simple Summary: Studying inflammasomes in red foxes is crucial for wildlife veterinary medicine, as it helps in treating and preventing inflammatory diseases in foxes. Inflammasomes, protein complexes in innate immune cells, regulate the release of interleukin (IL)-1β, a pro-inflammatory cytokine, in response to cytosolic danger signals, such as pathogens. Limited understanding exists regarding how inflammasome diversity across species influences pathogen carriage in red foxes. Through investigating the activation and intracellular mechanisms of fox inflammasomes, utilizing systems established in humans and mice, we compared the activating mechanism with that of humans and mice. Our research identified both similarities and differences in the fox inflammasome, providing insights that can be leveraged for treating and modulating veterinary medicine in foxes. Background: Inflammasomes recognize endogenous and exogenous danger signals, and subsequently induce the secretion of IL-1β. Studying inflammasomes in the red fox (Vulpes vulpes) is crucial for wildlife veterinary medicine, as it can help control inflammatory diseases in foxes. Methods: We investigated the activation and intracellular mechanisms of three inflammasomes (NLRP3, AIM2, and NLRC4) in fox peripheral blood mononuclear cells (PBMCs), using established triggers and inhibitors derived from humans and mice. Results: Fox PBMCs exhibited normal activation and induction of IL-1β secretion in response to representative inflammasome triggers (ATP and nigericin for NLRP3, dsDNA for AIM2, flagellin for NLRC4). Additionally, PBMCs showed normal IL-1β secretion when inoculated with inflammasome-activating bacteria. In inhibitors of the inflammasome signaling pathway, fox inflammasome activation was compared with mouse inflammasomes. MCC950, a selective NLRP3 inhibitor, suppressed the secretion of dsDNA- and flagellin-mediated IL-1β in foxes, unlike mice. Conclusions: These findings suggest that NLRP3 may have a common role in dsDNA- and flagellin-mediated inflammasome activation in the red fox. It implies that this fox inflammasome biology can be applied to the treatment of inflammasome-mediated diseases in the red fox. [ABSTRACT FROM AUTHOR]

Candidalysin (CL), a hydrophobic peptide toxin secreted by Candida albicans , is a key virulence factor that contributes to cytolysis, tissue damage, and immune activation. CL is thought to exert some of its biological activities, including IL-1β production, through the activation of the NLRP3-inflammasome pathway. To date, the mechanism by which CL affects human NLRP3 is not fully understood. We investigated specific activities of synthetic CL peptides using human-derived NLRP3-deficient cells. Two distinct synthetic CL peptide solutions were prepared: CLd, with CL completely solubilized as nanoparticles in dimethyl sulfoxide, and CLw, with CL partly solubilized in water, and including insoluble microparticles. THP-1 human monocytic cells and NLRP3-deficient THP-1 cells were differentiated into macrophages and stimulated with these peptide solutions. Cell membrane damage, lactate dehydrogenase release, IL-1β production, and caspase-1 activation in stimulated cells were subsequently evaluated. Both CLd and CLw exhibited cytotoxic activities independent of NLRP3. Importantly, CLd induced IL-1β production and caspase-1 activation in an NLRP3-independent manner, whereas these activities in CLw-stimulated cells were entirely NLRP3-dependent, suggesting that the NLRP3-dependent response might be triggered by insoluble microparticles. Our results demonstrate that inherent CL activities can cause cell damage and IL-1β production in an NLRP3-independent manner. Our research advances the elucidation of the role of NLRP3 in CL biological activity, underscoring the necessity for further exploration of the precise mechanisms underlying the NLRP3-independent effects of CL and providing novel insights into the complexity of host–pathogen interactions. [ABSTRACT FROM AUTHOR]

Abstract—The pathology of diseases arising from infections by viruses of Flaviviridae is largely determined by the development of systemic inflammation. The cytokines interleukin-1beta and interleukin-18 play a key role in triggering inflammation. Their secretion from cells, in its turn, is induced upon activation of inflammasomes. Activation of NLRP3 (NLR pyrin domain-containing family 3) inflammasomes was detected in cells infected with Flaviviridae. Some nonstructural proteins of these viruses have been shown to be able to activate or to inhibit the NLRP3 inflammasome, in particular, through interaction with its components. In this study, a functional NLRP3 inflammasome was reconstructed in human HEK293T cells and the effect of some nonstructural proteins of individual Flaviviridae viruses on it was studied. This model did not reveal any impact of nonstructural NS1 proteins of the West Nile virus, NS3 of hepatitis C virus, or NS5 of tick-borne encephalitis virus on the inflammasome components content. At the same time, in the presence of the NS1 of the West Nile virus and NS5 of the tick-borne encephalitis virus, the level of secretion of interleukin-1beta did not change, whereas in the presence of the NS3 protein of the hepatitis C virus, it increased by 1.5 times. Thus, NS3 can be considered as one of the factors of NLRP3 inflammasome activation and inflammatory pathogenesis in chronic hepatitis C virus infection. [ABSTRACT FROM AUTHOR]

Background: Alterations of astrocyte function play a crucial role in neuroinflammatory diseases due to either the loss of their neuroprotective role or the gain of their toxic inflammatory properties. Accumulating evidence highlights that cannabinoids and cannabinoid receptor agonists, such as WIN55,212-2 (WIN), reduce inflammation in cellular and animal models. Thus, the endocannabinoid system has become an attractive target to attenuate chronic inflammation in neurodegenerative diseases. However, the mechanism of action of WIN in astrocytes remains poorly understood. Objective: We studied the immunosuppressive property of WIN by examining gene expression patterns that were modulated by WIN in reactive astrocytes. Materials and Methods: Transcriptomic analysis by RNA-seq was carried out using primary human astrocyte cultures stimulated by the proinflammatory cytokine interleukin 1 beta (IL1β) in the presence or absence of WIN. Real-time quantitative polymerase chain reaction analysis was conducted on selected transcripts to characterize the dose-response effects of WIN, and to test the effect of selective antagonists of cannabinoid receptor 1 (CB1) and peroxisome proliferator-activated receptors (PPAR). Results: Transcriptomic analysis showed that the IL1β-induced inflammatory response is robustly inhibited by WIN pretreatment. WIN treatment alone also induced substantial gene expression changes. Pathway analysis revealed that the anti-inflammatory properties of WIN were linked to the regulation of kinase pathways and gene targets of neuroprotective transcription factors, including PPAR and SMAD (mothers against decapentaplegic homolog). The inhibitory effect of WIN was dose-dependent, but it was not affected by selective antagonists of CB1 or PPAR. Conclusions: This study suggests that targeting the endocannabinoid system may be a promising strategy to disrupt inflammatory pathways in reactive astrocytes. The anti-inflammatory activity of WIN is independent of CB1, suggesting that alternative receptors mediate the effects of WIN. These results provide mechanistic insights into the anti-inflammatory activity of WIN and highlight that astrocytes are a potential therapeutic target to ameliorate neuroinflammation in the brain.

Atherosclerosis is an inflammatory disease of the artery walls and involves immune cells such as macrophages. Olfactory receptors (OLFRs) are G protein–coupled chemoreceptors that have a central role in detecting odorants and the sense of smell. We found that mouse vascular macrophages express the olfactory receptor Olfr2 and all associated trafficking and signaling molecules. Olfr2 detects the compound octanal, which activates the NLR family pyrin domain containing 3 (NLRP3) inflammasome and induces interleukin-1β secretion in human and mouse macrophages. We found that human and mouse blood plasma contains octanal, a product of lipid peroxidation, at concentrations sufficient to activate Olfr2 and the human ortholog olfactory receptor 6A2 (OR6A2). Boosting octanal levels exacerbated atherosclerosis, whereas genetic targeting of Olfr2 in mice significantly reduced atherosclerotic plaques. Our findings suggest that inhibiting OR6A2 may provide a promising strategy to prevent and treat atherosclerosis.

Development of normal blood cells is often suppressed in juvenile myelomonocytic leukemia (JMML), a myeloproliferative neoplasm (MPN) of childhood, causing complications and impacting therapeutic outcomes. However, the mechanism underlying this phenomenon remains uncharacterized. To address this question, we induced the most common mutation identified in JMML (Ptpn11E76K) specifically in the myeloid lineage with hematopoietic stem cells (HSCs) spared. These mice uniformly developed a JMML-like MPN. Importantly, HSCs in the same bone marrow (BM) microenvironment were aberrantly activated and differentiated at the expense of self-renewal. As a result, HSCs lost quiescence and became exhausted. A similar result was observed in wild-type (WT) donor HSCs when co-transplanted with Ptpn11E76K/+ BM cells into WT mice. Co-culture testing demonstrated that JMML/MPN cells robustly accelerated differentiation in mouse and human normal hematopoietic stem/progenitor cells. Cytokine profiling revealed that Ptpn11E76K/+ MPN cells produced excessive IL-1β, but not IL-6, T NF-α, IFN-γ, IL-1α, or other inflammatory cytokines. Depletion of the IL-1β receptor effectively restored HSC quiescence, normalized their pool size, and rescued them from exhaustion in Ptpn11E76K/+/IL-1R-/- double mutant mice. These findings suggest IL-1β signaling as a potential therapeutic target for preserving normal hematopoietic development in JMML.

The role of the gastric mucosal microbiome in Helicobacter pylori-negative gastric cancer (GC) remains unclear. Therefore, we aimed to characterize the microbial alterations and host inflammatory cytokine responses in H. pylori-negative GC. Gastric mucosal samples were obtained from 137 H. pylori-negative patients with GC (n = 45) and controls (chronic gastritis or intestinal metaplasia, n = 92). We performed 16S rRNA gene sequencing (n = 67), a quantitative reverse transcription-polymerase chain reaction to determine the relative mRNA expression levels of TNF (tumor necrosis factor), IL1B (interleukin 1 beta), IL6 (interleukin 6), CXCL8 (C-X-C motif chemokine ligand 8), IL10 (interleukin 10), IL17A (interleukin 17A), TGFB1 (transforming growth factor beta 1) (n = 113), and the correlation analysis between sequencing and expression data (n = 47). Gastric mucosal microbiota in patients with GC showed reduced diversity and a significantly different composition compared to that of the controls. Lacticaseibacillus was significantly enriched, while Haemophilus and Campylobacter were depleted in the cancer group compared to the control group. These taxa could distinguish the two groups in a random forest algorithm. Moreover, the combined relative abundance of these taxa, a GC microbiome index, significantly correlated with gastric mucosal IL1B expression, which was elevated in the cancer group. Overall, altered gastric mucosal microbiota was found to be associated with increased mucosal IL1B expression in H. pylori-negative GC.

Background & aimsNonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. The NLRP3 inflammasome, a platform for caspase-1 activation and release of interleukin 1β, is increasingly recognized in the induction of inflammation and liver fibrosis during NAFLD. However, the cell-specific contribution of NLRP3 inflammasome activation in NAFLD remains unknown.MethodsTo investigate the role of NLRP3 inflammasome activation in hepatocytes, hepatic stellate cells (HSCs) and myeloid cells, a conditional Nlrp3 knock-out mouse was generated and bred to cell-specific Cre mice. Both acute and chronic liver injury models were used: lipopolysaccharide/adenosine-triphosphate to induce in vivo NLRP3 activation, choline-deficient, L-amino acid-defined high-fat diet, and Western-type diet to induce fibrotic nonalcoholic steatohepatitis (NASH). In vitro co-culture studies were performed to dissect the crosstalk between myeloid cells and HSCs.ResultsMyeloid-specific deletion of Nlrp3 blunted the systemic and hepatic increase in interleukin 1β induced by lipopolysaccharide/adenosine-triphosphate injection. In the choline-deficient, L-amino acid-defined high-fat diet model of fibrotic NASH, myeloid-specific Nlrp3 knock-out but not hepatocyte- or HSC-specific knock-out mice showed significant reduction in inflammation independent of steatosis development. Moreover, myeloid-specific Nlrp3 knock-out mice showed ameliorated liver fibrosis and decreased HSC activation. These results were validated in the Western-type diet model. In vitro co-cultured studies with human cell lines demonstrated that HSC can be activated by inflammasome stimulation in monocytes, and this effect was significantly reduced if NLRP3 was downregulated in monocytes.ConclusionsThe study provides new insights in the cell-specific role of NLRP3 in liver inflammation and fibrosis. NLRP3 inflammasome activation in myeloid cells was identified as crucial for the progression of NAFLD to fibrotic NASH. These results may have implications for the development of cell-specific strategies for modulation of NLRP3 activation for treatment of fibrotic NASH.

Non-alcoholic fatty liver disease (NAFLD) affects up to 20% of the world's population. Overactivation of the angiotensin receptor type 1 (AT1) contributes to metabolic dysfunction and increased oxidant production, which are associated with NAFLD and impaired hepatic lipid metabolism. Nuclear factor erythroid-2-related factor 2 (Nrf2) regulates the expression of antioxidant phase II genes by binding to the antioxidant response element (ARE); however, the mechanisms by which AT1 contributes to this pathway during the progression of NAFLD remain unresolved. To investigate hepatic Nrf2 response to a hyperglycemic challenge, we studied three groups of rats (male, 10-weeks-old): (1) untreated, lean Long Evans Tokushima Otsuka (LETO), (2) untreated, obese Otsuka Long Evans Tokushima Fatty (OLETF), and (3) OLETF + angiotensin receptor blocker (OLETF + ARB; 10 mg olmesartan/kg/d × 6 weeks). Livers were collected after overnight fasting (T0; baseline), and 1 h and 2 h post-oral glucose load. At baseline, chronic AT1 blockade increased nuclear Nrf2 content, reduced expression of glutamate-cysteine ligase catalytic (GCLC) subunit, glutathione peroxidase 1 (GPx1), and superoxide dismutase 2 (SOD2), mitochondrial catalase activity, and hepatic 4-hydroxy-2-nonenal (4-HNE) content. The expression of hepatic interleukin-1 beta (IL-1β) and collagen type IV, which are associated with liver fibrosis, were decreased with AT1 blockade. Glucose increased Nrf2 translocation in OLETF but was reduced in ARB, suggesting that glucose induces the need for antioxidant defense that is ameliorated with ARB. These results suggest that overactivation of AT1 promotes oxidant damage by suppressing Nrf2 and contributing to hepatic fibrosis associated with NAFLD development.

Febrile infection-related epilepsy syndrome (FIRES) characteristically affects previously healthy children, who experience a sudden and explosive onset of super-refractory status epilepticus preceded by febrile infection and accompanied by fulminant neurogenic inflammation. FIRES, however, can affect individuals of all ages and is a subcategory of new-onset refractory status epilepticus. This definition of FIRES excludes febrile status epilepticus in infants. FIRES is a rare type of epileptic encephalopathy with rapidly progressive onset of seizures and a devastating prognosis, as drug-resistant epilepsy often follows without a latency period. Although the exact pathogenesis of FIRES has not been elucidated, a functional deficiency in the endogenous interleukin-1 receptor antagonist has been implicated in a genetic predisposition to FIRES. Dysregulation of the interleukin-1β–interleukin-1 receptor 1 (IL-1β–IL-1R1) signaling pathway appears to be involved in the pathogenesis of FIRES. In this review, the authors summarize the definition of FIRES, IL-1β–IL-1R1 signaling, the nucleotide-binding oligomerization domain the NLRP3 inflammasome, and IL-1 targeted therapy for FIRES.

BACKGROUNDMultisystem inflammatory syndrome in children (MIS-C) is a rare but potentially severe illness that follows exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Kawasaki disease (KD) shares several clinical features with MIS-C, which prompted the use of intravenous immunoglobulin (IVIG), a mainstay therapy for KD. Both diseases share a robust activation of the innate immune system, including the IL-1 signaling pathway, and IL-1 blockade has been used for the treatment of both MIS-C and KD. The mechanism of action of IVIG in these 2 diseases and the cellular source of IL-1β have not been defined.METHODSThe effects of IVIG on peripheral blood leukocyte populations from patients with MIS-C and KD were examined using flow cytometry and mass cytometry (CyTOF) and live-cell imaging.RESULTSCirculating neutrophils were highly activated in patients with KD and MIS-C and were a major source of IL-1β. Following IVIG treatment, activated IL-1β+ neutrophils were reduced in the circulation. In vitro, IVIG was a potent activator of neutrophil cell death via PI3K and NADPH oxidase, but independently of caspase activation.CONCLUSIONSActivated neutrophils expressing IL-1β can be targeted by IVIG, supporting its use in both KD and MIS-C to ameliorate inflammation.FUNDINGPatient Centered Outcomes Research Institute; NIH; American Asthma Foundation; American Heart Association; Novo Nordisk Foundation; NIGMS; American Academy of Allergy, Asthma and Immunology Foundation.

[Figure: see text].

Acute respiratory distress syndrome (ARDS), an inflammatory condition with high mortality rates, is common in severe COVID-19, whose risk is reduced by metformin rather than other anti-diabetic medications. Detecting of inflammasome assembly in post-mortem COVID-19 lungs, we asked whether and how metformin inhibits inflammasome activation while exerting its anti-inflammatory effect. We show that metformin inhibited NLRP3 inflammasome activation and interleukin (IL)-1β production in cultured and alveolar macrophages along with inflammasome-independent IL-6 secretion, thus attenuating lipopolysaccharide (LPS)- and SARS-CoV-2-induced ARDS. By targeting electron transport chain complex 1 and independently of AMP-activated protein kinase (AMPK) or NF-κB, metformin blocked LPS-induced and ATP-dependent mitochondrial (mt) DNA synthesis and generation of oxidized mtDNA, an NLRP3 ligand. Myeloid-specific ablation of LPS-induced cytidine monophosphate kinase 2 (CMPK2), which is rate limiting for mtDNA synthesis, reduced ARDS severity without a direct effect on IL-6. Thus, inhibition of ATP and mtDNA synthesis is sufficient for ARDS amelioration.

A challenge for central nervous system (CNS) tissue analysis in neuroscience research has been the difficulty to codetect and colocalize gene and protein expression in the same tissue. Given the importance of identifying gene expression relative to proteins of interest, for example, cell-type specific markers, we aimed to develop a protocol to optimize their codetection. RNAscope fluorescent in situ hybridization (FISH) combined with immunohistochemistry (IHC) in fixed (CNS) tissue sections allows for reliable quantification of gene transcripts of interest within IHC-labeled cells. This paper describes a new method for simultaneous visualization of FISH and IHC in thicker (14-µm), fixed tissue samples, using spinal cord sections. This method's effectiveness is shown by the cell-type-specific quantification of two genes, namely the proinflammatory cytokine interleukin-1beta (IL-1b) and the inflammasome NLR family pyrin domain containing 3 (NLRP3). These genes are challenging to measure accurately using immunohistochemistry (IHC) due to the nonspecificity of available antibodies and the hard-todistinguish, dot-like visualizations of the labeled proteins within the tissue. These measurements were carried out in spinal cord sections after unilateral chronic constriction injury of the sciatic nerve to induce neuroinflammation in the spinal cord. RNAscope is used to label transcripts of genes of interest and IHC is used to label cell-type specific antigens (IBA1 for microglia, NeuN for neurons). This combination allowed for labeled RNA transcripts to be quantified within celltype specific boundaries using confocal microscopy and standard image analysis methods. This method makes it easy to answer empirical questions that are intractable with standard IHC or in situ hybridization alone. The method, which has been optimized for spinal cord tissue and to minimize tissue preparation time and costs, is described in detail from tissue collection to image analysis. Further, the relative expression changes in inflammatory genes NLRP3 and IL-1b in spinal cord microglia vs. neurons of somatotopically relevant laminae are described for the first time. [ABSTRACT FROM AUTHOR]

Febrile infection-related epilepsy syndrome (FIRES) characteristically affects previously healthy children, who experience a sudden and explosive onset of super-refractory status epilepticus preceded by febrile infection and accompanied by fulminant neurogenic inflammation. FIRES, however, can affect individuals of all ages and is a subcategory of new-onset refractory status epilepticus. This definition of FIRES excludes febrile status epilepticus in infants. FIRES is a rare type of epileptic encephalopathy with rapidly progressive onset of seizures and a devastating prognosis, as drug-resistant epilepsy often follows without a latency period. Although the exact pathogenesis of FIRES has not been elucidated, a functional deficiency in the endogenous interleukin-1 receptor antagonist has been implicated in a genetic predisposition to FIRES. Dysregulation of the interleukin-1β–interleukin-1 receptor 1 (IL-1β–IL-1R1) signaling pathway appears to be involved in the pathogenesis of FIRES. In this review, the authors summarize the definition of FIRES, IL-1β–IL-1R1 signaling, the nucleotide-binding oligomerization domain the NLRP3 inflammasome, and IL-1 targeted therapy for FIRES. [ABSTRACT FROM AUTHOR]

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Toxoplasmic encephalitis can develop in individuals infected with the protozoan parasite Toxoplasma gondii and is typified by parasite replication and inflammation within the brain. Patients often present with seizures, but the parasite genes and host pathways involved in seizure development and/or propagation are unknown. We previously reported that seizure induction in Toxoplasma-infected mice is parasite strain dependent. Using quantitative trait locus mapping, we identify four loci in the Toxoplasma genome that potentially correlate with seizure development. In one locus, we identify the polymorphic virulence factor, GRA15, as a Toxoplasma gene associated with onset of seizures. GRA15 was previously shown to regulate host NF-κB-dependent gene expression during acute infections, and we demonstrate a similar role for GRA15 in brains of toxoplasmic encephalitic mice. GRA15 is important for increased expression of interleukin 1 beta (IL-1β) and other IL-1 pathway host genes, which is significant since IL-1 signaling is involved in onset of seizures. Inhibiting IL-1 receptor signaling reduced seizure severity in Toxoplasma-infected mice. These data reveal one mechanism by which seizures are induced during toxoplasmic encephalitis. IMPORTANCE Inflammation in the brain caused by infections lead to seizures and other neurological symptoms. But the microbial products that induce seizures as well as the host pathways downstream of these factors are largely unknown. Using a nonbiased genetic screening approach, we identify 4 loci in the Toxoplasma genome that correlate with the induction of seizures in Toxoplasma-infected mice. One of these loci contains the gene, GRA15, which we demonstrate is associated with seizure development in toxoplasmic encephalitic mice. GRA15 accomplishes this in part by activating host pathways that lead to increased IL-1 receptor signaling and that inhibition of this signaling inhibits Toxoplasma-induced seizures.

The COVID-19 pandemic has affected over 114 million people and has resulted in >2.5 million deaths so far. Some people have greater susceptibility which influences both SARS-CoV-2 infectivity and COVID-19 severity. Smoking is associated with increased ACE-2, the receptor for SARS-CoV-2, which facilitates its entry through the lung. However, despite the widespread use of e-cigarettes, also known as vaping, little is known regarding the effects of vaping on ACE-2 expression and how this affects SARS-CoV-2 infection. In addition, the added effect of nicotine in the vapor is also unknown. Thus, we tested whether vaping induces ACE-2 expression in the mouse lung. BALB/c mice exposed to e-cigarette vapor (±nicotine) resulted in a significant increase in peribronchiolar inflammation and influx of immune cells into the airways. Vapor increased monocyte chemoattractant protein-1, interleukin 1β, and KC levels in bronchoalveolar lavage fluid in both sexes, which were further enhanced by nicotine (whereas increase in interleukin 6 was sex and nicotine independent). The reduction in basal inspiratory capacity with vapor exposure occurred independent of sex or nicotine. The increase in methacholine-induced airway hyper-responsiveness was independent of sex; however, in female mice it was only significant in the nicotine-exposed group. Lung ACE-2 expression was increased in male mice in a nicotine-dependent manner as compared with female mice. Collectively, while vaping (±nicotine) induced airway inflammation and impaired lung function, the induction of lung ACE-2 occurred to a significantly greater degree in males exposed to vapor containing nicotine as compared with females. Thus, via these effects on ACE-2 expression in the lungs and airways, vaping itself may facilitate SARS-CoV-2 entry into the airways.

As organelles of the innate immune system, inflammasomes activate caspase-1 and other inflammatory caspases that cleave gasdermin D (GSDMD). Caspase-1 also cleaves inactive precursors of the interleukin (IL)-1 family to generate mature cytokines such as IL-1β and IL-18. Cleaved GSDMD forms transmembrane pores to enable the release of IL-1 and to drive cell lysis through pyroptosis1-9. Here we report cryo-electron microscopy structures of the pore and the prepore of GSDMD. These structures reveal the different conformations of the two states, as well as extensive membrane-binding elements including a hydrophobic anchor and three positively charged patches. The GSDMD pore conduit is predominantly negatively charged. By contrast, IL-1 precursors have an acidic domain that is proteolytically removed by caspase-110. When permeabilized by GSDMD pores, unlysed liposomes release positively charged and neutral cargoes faster than negatively charged cargoes of similar sizes, and the pores favour the passage of IL-1β and IL-18 over that of their precursors. Consistent with these findings, living-but not pyroptotic-macrophages preferentially release mature IL-1β upon perforation by GSDMD. Mutation of the acidic residues of GSDMD compromises this preference, hindering intracellular retention of the precursor and secretion of the mature cytokine. The GSDMD pore therefore mediates IL-1 release by electrostatic filtering, which suggests the importance of charge in addition to size in the transport of cargoes across this large channel.

Melanoma differentiation associated gene-9 (MDA-9), Syntenin-1, or syndecan binding protein is a differentially regulated prometastatic gene with elevated expression in advanced stages of melanoma. MDA-9/Syntenin expression positively associates with advanced disease stage in multiple histologically distinct cancers and negatively correlates with patient survival and response to chemotherapy. MDA-9/Syntenin is a highly conserved PDZ-domain scaffold protein, robustly expressed in a spectrum of diverse cancer cell lines and clinical samples. PDZ domains interact with a number of proteins, many of which are critical regulators of signaling cascades in cancer. Knockdown of MDA-9/Syntenin decreases cancer cell metastasis, sensitizing these cells to radiation. Genetic silencing of MDA-9/Syntenin or treatment with a pharmacological inhibitor of the PDZ1 domain, PDZ1i, also activates the immune system to kill cancer cells. Additionally, suppression of MDA-9/Syntenin deregulates myeloid-derived suppressor cell differentiation via the STAT3/interleukin (IL)-1β pathway, which concomitantly promotes activation of cytotoxic T lymphocytes. Biologically, PDZ1i treatment decreases metastatic nodule formation in the lungs, resulting in significantly fewer invasive cancer cells. In summary, our observations indicate that MDA-9/Syntenin provides a direct therapeutic target for mitigating aggressive breast cancer and a small-molecule inhibitor, PDZ1i, provides a promising reagent for inhibiting advanced breast cancer pathogenesis.

Bipolar disorder (BD) is characterized by cyclical mood shifts. Studies indicate that BD patients have a peripheral pro-inflammatory state and alterations in glial populations in the brain. We utilized an in vitro model to study inflammation-related phenotypes of astrocytes derived from induced pluripotent stem cells (iPSCs) generated from BD patients and healthy controls. BD astrocytes showed changes in transcriptome and induced a reduction in neuronal activity when co-cultured with neurons. IL-1β-stimulated BD astrocytes displayed a unique inflammatory gene expression signature and increased secretion of IL-6. Conditioned medium from stimulated BD astrocytes reduced neuronal activity, and this effect was partially blocked by IL-6 inactivating antibody. Our results suggest that BD astrocytes are functionally less supportive of neuronal excitability and this effect is partially mediated by IL-6. We confirmed higher IL-6 in blood in a distinct cohort of BD patients, highlighting the potential role of astrocyte-mediated inflammatory signaling in BD neuropathology.

Effective clearance of neurotoxic amyloid-beta (Aβ) from the brain is a critical process to prevent Alzheimer's disease (AD). One major clearance mechanism is Aβ transcytosis mediated by low-density lipoprotein receptor-related protein 1 (LRP1) in capillary endothelial cells. A marked loss of endothelial LRP1 is found in AD brains and is believed to significantly impair Aβ clearance. Recently, we demonstrated that pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, significantly down-regulated LRP1 in human primary microvascular endothelial cells (MVECs). In this study, we sought to determine the underlying molecular mechanism by which IL-1β led to LRP1 loss in MVECs. Reduced LRP1 protein and transcript were detected up to 24 h post-exposure and returned to the baseline levels after 48 h post-exposure with 1 ng/ml IL-1β. This reduction was in part mediated by microRNA-205-5p, -200b-3p, and -200c-3p, as these microRNAs were concomitantly upregulated in MVECs exposed to IL-1β. Synthetic microRNA-205-5p, -200b-3p, and -200c-3p mimics recapitulated LRP1 loss in MVECs without IL-1β, and their synthetic antagomirs effectively reversed IL-1β-mediated LRP1 loss. Importantly, we found that the expression of these three microRNAs was controlled by NF-κB as pharmacological NF-κB inhibitor, BMS-345541, inhibited the IL-1β-mediated upregulation of these microRNAs and rescued LRP1 expression. siRNA-mediated silencing of IκB in MVECs elevated microRNA-200b-3p and decreased LRP1 transcript, partially confirming our overall findings. In conclusion, our study provides a mechanism by which pro-inflammatory IL-1β instigates the suppression of LRP1 expression in MVECs. Our findings could implicate spatiotemporal loss of LRP1 and impairment of the LRP1-mediated clearance mechanism by endothelial cells.

ObjectiveJoint injury rapidly induces expression of primary response genes (PRGs), which activate a cascade of secondary genes that destroy joint tissues and initiate post-traumatic osteoarthritis (PTOA). Bromodomain-containing-protein-4 (Brd4) and cyclin-dependent-kinase-9 (CDK9) cooperatively control the rate-limiting step of PRG transactivation, including pro-inflammatory genes. This study investigated whether Brd4 and CDK9 inhibitors suppress inflammation and prevent PTOA development in vitro and in a mouse PTOA model.MethodsThe effects of Brd4 and CDK9 inhibitors (JQ1 and Flavopiridol) on PRG and associated secondary damage were rigorously tested in different settings. Short-term effects of inflammatory stimuli (IL-1β, IL-6, TNF) on human chondrocyte PRG expression were assessed by RT-PCR and microarray after 5-h. We quantified glycosaminoglycan release from IL-1β-treated bovine cartilage explants after 3-6 days, and osteoarthritic changes in mice after ACL-rupture using RT-PCR (2-24hrs), in vivo imaging of MMP activity (24hrs), AFM-nanoindentation (3-7days), and histology (3days-4wks).ResultsFlavopiridol and JQ1 inhibitors act synergistically, and a combination of both almost completely prevented the activation of most IL-1β-induced PRGs in vitro by microarray analysis, and prevented IL-1β-induced glycosaminoglycan release from cartilage explants. Mice given the drug combination showed reduced IL-1β and IL-6 expression, less in vivo MMP activity, and lower synovitis (1.5 vs 4.9) and OARSI scores (2.8 vs 6.0) than untreated mice with ACL-rupture.ConclusionsJQ1 and Flavopiridol work synergistically to reduce injury response after joint trauma, suggesting that targeting Brd4 and/or CDK9 could be a viable strategy for PTOA prevention and treatment of early OA.

Background & aimsIncreased hepatocyte death contributes to the pathology of acute and chronic liver diseases. However, the role of hepatocyte pyroptosis and extracellular inflammasome release in liver disease is unknown.MethodsWe used primary mouse and human hepatocytes, hepatocyte-specific leucine 351 to proline Nlrp3KICreA mice, and GsdmdKO mice to investigate pyroptotic cell death in hepatocytes and its impact on liver inflammation and damage. Extracellular NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasomes were isolated from mutant NLRP3-YFP HEK cells and internalisation was studied in LX2 and primary human hepatic stellate cells. We also examined a cohort of 154 adult patients with biopsy-proven non-alcoholic fatty liver disease (Sir Charles Gairdner Hospital, Nedlands, Western Australia).ResultsWe demonstrated that primary mouse and human hepatocytes can undergo pyroptosis upon NLRP3 inflammasome activation with subsequent release of NLRP3 inflammasome proteins that amplify and perpetuate inflammasome-driven fibrogenesis. Pyroptosis was inhibited by blocking caspase-1 and gasdermin D activation. The activated form of caspase-1 was detected in the livers and in serum from patients with non-alcoholic steatohepatitis and correlated with disease severity. Nlrp3KICreA mice showed spontaneous liver fibrosis under normal chow diet, and increased sensitivity to liver damage and inflammation after treatment with low dose lipopolysaccharide. Mechanistically, hepatic stellate cells engulfed extracellular NLRP3 inflammasome particles leading to increased IL-1β secretion and α-smooth muscle actin expression. This effect was abrogated when cells were pre-treated with the endocytosis inhibitor cytochalasin B.ConclusionsThese results identify hepatocyte pyroptosis and release of inflammasome components as a novel mechanism to propagate liver injury and liver fibrosis development.Lay summaryOur findings identify a novel mechanism of inflammation in the liver. Experiments in cell cultures, mice, and human samples show that a specific form of cell death, called pyroptosis, leads to the release of complex inflammatory particles, the NLRP3 inflammasome, from inside hepatocytes into the extracellular space. From there they are taken up by other cells and thereby mediate inflammatory and pro-fibrogenic stress signals. The discovery of this mechanism may lead to novel treatments for chronic liver diseases in the future.

Talaromyce marneffei is an important thermally dimorphic pathogen causing disseminated mycoses in immunocompromised individuals in southeast Asia. Previous studies have suggested that NLRP3 inflammasome plays a critical role in antifungal immunity. However, the mechanism underlying the role of NLRP3 inflammasome activation in host defense against T. marneffei remains unclear. We show that T. marneffei yeasts but not conidia induce potent IL-1β production. The IL-1β response to T. marneffei yeasts is differently regulated in different cell types; T. marneffei yeasts alone are able to induce IL-1β production in human PBMCs and monocytes, whereas LPS priming is essential for IL-1β response to yeasts. We also find that Dectin-1/Syk signaling pathway mediates pro-IL-1β production, and NLRP3-ASC-caspase-1 inflammasome is assembled to trigger the processing of pro-IL-1β into IL-1β. In vivo, mice deficient in NLRP3 or caspase-1 exhibit higher mortality rate and fungal load compared to wild-type mice after systemic T. marneffei infection, which correlates with the diminished recruitment of CD4 T cells into granulomas in knockout mice. Thus, our study first demonstrates that NLRP3 inflammasome contributes to host defense against T. marneffei infection.

Despite the integration of salivary inflammatory cytokines into research across the biobehavioral, psychological, clinical, and health-related disciplines, there is little guidance regarding the biospecimen collection, handling, and storage practices that maximize the quality and validity of salivary cytokine data. Furthermore, associations between salivary cytokines and measures related to oral health are rarely assessed and accounted for in studies outside the oral health fields. To address these gaps, we examine the sensitivity of salivary interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) to changes in saliva sample collection technique and cold chain management procedures. Using subsets of saliva samples collected from 150 healthy adults, we measure salivary IL-1β, IL-6, IL-8, TNF-α, and other oral health-related indices (i.e., blood contamination [transferrin], and salivary matrixmallotprotienase-8). In addition to examining changes in cytokine levels associated with sample collection technique and cold chain management procedures, we assess relations between cytokine concentrations and levels of other oral health-related measures. We found that IL-1β, IL-6, and IL-8 were more robust to changes in sample collection and cold chain management procedures than TNF-α, and all cytokines were positively associated with other oral health-related measures. Based on our findings, we recommend analyte-specific guidance for measuring and interpreting salivary cytokine concentrations.

The purpose of the study is to determine the prevalence of interleukin (IL)-1A (rs1800587), IL-1B (rs1143634) and vitamin D receptor (VDR) (TaqI, rs731236) gene polymorphisms in the Turkish population and their association with Stage III Grade B/C periodontitis. Systemically and periodontally healthy individuals (N = 100) and Stage III Grade B/C periodontitis patients (N=100) based on clinical and radiographic examination were included in this research. Clinical attachment level, probing depth, bleeding on probing, plaque and gingival indices of the subjects were measured. Genotyping of IL-1A (rs1800587), IL-1B (rs1143634) and VDR (rs731236) polymorphisms was conducted by Real Time PCR. Allelic and genotypic distributions of IL-1A (rs1800587) gene polymorphism were not associated with periodontitis (p>0.05). In IL-1B (rs1143634) gene polymorphism, the C allele was detected more frequently in healthy individuals compared with the periodontitis patients (p=0.045). CC genotype and C allele in VDR (rs731236) gene polymorphism was higher in periodontitis patients (p=0.031, p=0.034, respectively). In comparison with Grade B periodontitis patients and healthy subjects, CC genotype and C allele were observed more frequently in the Grade B periodontitis in terms of alleles (C/T) and genotypes for VDR (rs731236) polymorphism (p=0.024, p=0.008, respectively). This study presents that the VDR (rs731236) polymorphism are associated with enhanced susceptibility to Stage III periodontitis in the Turkish population. Furthermore, VDR (rs731236) polymorphism may be used as an identification criteria to discriminate Grade B and Grade C in Stage III periodontitis.

Gasdermin-D (GSDMD) in inflammasome-activated macrophages is cleaved by caspase-1 to generate N-GSDMD fragments. N-GSDMD then oligomerizes in the plasma membrane (PM) to form pores that increase membrane permeability, leading to pyroptosis and IL-1β release. In contrast, we report that although N-GSDMD is required for IL-1β secretion in NLRP3-activated human and murine neutrophils, N-GSDMD does not localize to the PM or increase PM permeability or pyroptosis. Instead, biochemical and microscopy studies reveal that N-GSDMD in neutrophils predominantly associates with azurophilic granules and LC3+ autophagosomes. N-GSDMD trafficking to azurophilic granules causes leakage of neutrophil elastase into the cytosol, resulting in secondary cleavage of GSDMD to an alternatively cleaved N-GSDMD product. Genetic analyses using ATG7-deficient cells indicate that neutrophils secrete IL-1β via an autophagy-dependent mechanism. These findings reveal fundamental differences in GSDMD trafficking between neutrophils and macrophages that underlie neutrophil-specific functions during inflammasome activation.

Aims/hypothesisAggregation of the beta cell secretory product human islet amyloid polypeptide (hIAPP) results in islet amyloid deposition, a pathological feature of type 2 diabetes. Amyloid formation is associated with increased levels of islet IL-1β as well as beta cell dysfunction and death, but the mechanisms that promote amyloid deposition in situ remain unclear. We hypothesised that physiologically relevant concentrations of IL-1β stimulate beta cell islet amyloid polypeptide (IAPP) release and promote amyloid formation.MethodsWe used a humanised mouse model of endogenous beta cell hIAPP expression to examine whether low (pg/ml) concentrations of IL-1β promote islet amyloid formation in vitro. Amyloid-forming islets were cultured for 48 h in the presence or absence of IL-1β with or without an IL-1β neutralising antibody. Islet morphology was assessed by immunohistochemistry and islet mRNA expression, hormone content and release were also quantified. Cell-free thioflavin T assays were used to monitor hIAPP aggregation kinetics in the presence and absence of IL-1β.ResultsTreatment with a low concentration of IL-1β (4 pg/ml) for 48 h increased islet amyloid prevalence (93.52 ± 3.89% vs 43.83 ± 9.67% amyloid-containing islets) and amyloid severity (4.45 ± 0.82% vs 2.16 ± 0.50% amyloid area/islet area) in hIAPP-expressing mouse islets in vitro. This effect of IL-1β was reduced when hIAPP-expressing islets were co-treated with an IL-1β neutralising antibody. Cell-free hIAPP aggregation assays showed no effect of IL-1β on hIAPP aggregation in vitro. Low concentration IL-1β did not increase markers of the unfolded protein response (Atf4, Ddit3) or alter proIAPP processing enzyme gene expression (Pcsk1, Pcsk2, Cpe) in hIAPP-expressing islets. However, release of IAPP and insulin were increased over 48 h in IL-1β-treated vs control islets (IAPP 0.409 ± 0.082 vs 0.165 ± 0.051 pmol/5 islets; insulin 87.5 ± 8.81 vs 48.3 ± 17.3 pmol/5 islets), and this effect was blocked by co-treatment with IL-1β neutralising antibody.Conclusions/interpretationUnder amyloidogenic conditions, physiologically relevant levels of IL-1β promote islet amyloid formation by increasing beta cell release of IAPP. Neutralisation of this effect of IL-1β may decrease the deleterious effects of islet amyloid formation on beta cell function and survival.

BackgroundPulmonary damage by Pseudomonas aeruginosa during cystic fibrosis lung infection and ventilator-associated pneumonia is mediated both by pathogen virulence factors and host inflammation. Impaired immune function due to tissue damage and inflammation, coupled with pathogen multidrug resistance, complicates the management of these deep-seated infections. Pathological inflammation during infection is driven by interleukin-1β (IL-1β), but the molecular processes involved are not fully understood.MethodsWe examined IL-1β activation in a pulmonary model infection of Pseudomonas aeruginosa and in vitro using genetics, specific inhibitors, recombinant proteins, and targeted reporters of protease activity and IL-1β bioactivity.FindingsCaspase-family inflammasome proteases canonically regulate maturation of this proinflammatory cytokine, but we report that plasticity in IL-1β proteolytic activation allows for its direct maturation by the pseudomonal protease LasB. LasB promotes IL-1β activation, neutrophilic inflammation, and destruction of lung architecture characteristic of severe P. aeruginosa pulmonary infection.InterpretationPreservation of lung function and effective immune clearance may be enhanced by selectively controlling inflammation. Discovery of this IL-1β regulatory mechanism provides a distinct target for anti-inflammatory therapeutics, such as matrix metalloprotease inhibitors that inhibit LasB and limit inflammation and pathology during P. aeruginosa pulmonary infections.FundingFull details are provided in the Acknowledgements section.

A challenge for central nervous system (CNS) tissue analysis in neuroscience research has been the difficulty to codetect and colocalize gene and protein expression in the same tissue. Given the importance of identifying gene expression relative to proteins of interest, for example, cell-type specific markers, we aimed to develop a protocol to optimize their codetection. RNAscope fluorescent in situ hybridization (FISH) combined with immunohistochemistry (IHC) in fixed (CNS) tissue sections allows for reliable quantification of gene transcripts of interest within IHC-labeled cells. This paper describes a new method for simultaneous visualization of FISH and IHC in thicker (14-μm), fixed tissue samples, using spinal cord sections. This method’s effectiveness is shown by the cell-type-specific quantification of two genes, namely the proinflammatory cytokine interleukin-1beta (IL-1b) and the inflammasome NLR family pyrin domain containing 3 (NLRP3). These genes are challenging to measure accurately using immunohistochemistry (IHC) due to the nonspecificity of available antibodies and the hard-to-distinguish, dot-like visualizations of the labeled proteins within the tissue. These measurements were carried out in spinal cord sections after unilateral chronic constriction injury of the sciatic nerve to induce neuroinflammation in the spinal cord. RNAscope is used to label transcripts of genes of interest and IHC is used to label cell-type specific antigens (IBA1 for microglia, NeuN for neurons). This combination allowed for labeled RNA transcripts to be quantified within cell-type specific boundaries using confocal microscopy and standard image analysis methods. This method makes it easy to answer empirical questions that are intractable with standard IHC or in situ hybridization alone. The method, which has been optimized for spinal cord tissue and to minimize tissue preparation time and costs, is described in detail from tissue collection to image analysis. Further, the relative expression changes in inflammatory genes NLRP3 and IL-1b in spinal cord microglia vs. neurons of somatotopically relevant laminae are described for the first time.

Objective To investigate effects of malt extract (ME) on the proliferation and secretion of prolactin (PRL) in anterior pituitary cells of hyperprolactinemia (HPRL) rats by regulating the Nod-like receptor protein 3(NLRP3)/ cysteine aspartic specific protease-1 (Caspase-1)/ interleukin-1β (IL-1β) pathway. Methods The anterior pituitary cells of normal and HPRL rats were separated and named as the NC group and the model group. The expression levels of growth hormone and PRL in cells were identified by immunohistochemistry. Cells in the model group were treated with 0 mg/L ME, 25 mg/L ME, 50 mg/L ME, 100 mg/L ME, 5 mmol/L Adenosine 5'-triphosphate (ATP), 100 mg/L ME and 5 mmol/L ATP for 48 h, and named as the Blank group, the ME low dose group (ME-L group), the ME medium dose group (ME-M group), the ME high dose group (ME-H group), the ATP (NLRP3 activator) group and ME-H+ATP group. The morphology of cells in each group was observed by light microscope. Cell proliferation was detected by CCK-8 method. Cell apoptosis was detected by flow cytometry. The level of PRL in the supernatant of rat anterior pituitary cells was detected by ELISA. Western blot assay was applied to detect expression levels of proliferating cell nuclear antigen (PCNA), dopamine receptor D2 (DRD2), dopamine transporter (DAT), NLRP3, Caspase-1 and IL-1β in rat anterior pituitary cells. Results Rat anterior pituitary cells were isolated successfully. Compared with the NC group, the volume of anterior pituitary cells was smaller and the shape was irregular, the OD450 value, prolactin level, DAT, PCNA, NLRP3, Caspase-1, IL-1β protein expression increased, and the apoptosis rate and DRD2 protein expression decreased in the blank group (P＜0.05). Compared with the blank group, the morphology of anterior pituitary cells was improved in the ME-L group, the ME-M group and the ME-H group. The OD450 value, prolactin level, DAT, PCNA, NLRP3, Caspase-1 and IL-1β protein expression levels decreased, and the apoptosis rate and DRD2 protein expression increased in a dose-dependent manner. The change trend of the corresponding indexes was contrary to the above in the ATP group (P＜0.05). ATP attenuated the inhibitory effect of high-dose ME on the proliferation of anterior pituitary cells and PRL secretion in HPRL rats. Conclusion ME may inhibit the proliferation and PRL secretion of HPRL rat anterior pituitary cells by down-regulating the NLRP3/Caspase-1/IL-1β pathway. [ABSTRACT FROM AUTHOR]