Uric acid-driven Th17 differentiation requires inflammasome-derived IL-1 and IL-18

Understanding the interplay between psoriatic arthritis and gout: "Psout"

The interplay between Psoriatic arthritis and Gout is a current diagnostic challenge faced by many physicians and researchers. We aimed at reviewing the coexistence of gout and its features such as hyperuricemia and deposition of monosodium urate crystals in patients with psoriatic arthritis (PsA). We also focused on a brief presentation of the pathophysiology underneath the interplay between PsA and gout, and ultimately on recommendation of approaches for the differential diagnosis. The literature search for this narrative review was conducted using PubMed and Medline and after retrieving and screening the references, articles were selected according to the inclusion and exclusion criteria. Part of the assessed studies reported the coexistence of PsA and gout (Psout) and its association with several clinical outcomes among affected patients. Other studies stressed incidences of misdiagnosis of gout with PsA and vice versa. Additionally, the presence of hyperuricemia in PsA patients could interfere with the patient's characteristics and outcomes of their treatment. Further research on the assessment and clinical course of Psout is required to develop an official protocol for its diagnosis and treatment.

Exploration of the potential mechanism of Yiyi Tongfeng Formula in the treatment of acute gouty arthritis based on network pharmacology and molecular docking: A review

The global prevalence of gout is on the rise. Yiyi Tongfeng Formula (YTF), a traditional herbal compound, has gained recognition for its efficacy in managing acute gouty arthritis (AGA). Despite its widespread use, the underlying mechanisms of YTF in AGA treatment remain largely undefined. This study employed network pharmacology and molecular docking to elucidate these mechanisms. We utilized the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, SymMap database, and various literature sources to identify active components and corresponding targets of YTF. Relevant AGA-associated targets were identified through the Genecards, Drugbank, Therapeutic Target Database, and Online Mendelian Inheritance in Man databases. A protein-protein interaction network was constructed to delineate interactions between YTF targets and AGA. Key ingredients and central targets were further analyzed using Cytoscape. Functional enrichment analyses, including Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, were conducted via Metascape. Additionally, molecular docking studies were performed using PyMOL and AutoDock4. It was found that quercetin, kaempferol, and luteolin may be the main active components of YTF for AGA treatment. Gene Ontology enrichment analysis shows that the main biological processes involved are cellular responses to lipids, and inflammatory responses. Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggests the involvement of the IL-17 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, and so on. The findings suggest a multi-faceted therapeutic approach of YTF in treating AGA, involving multiple components, targets, biological processes, and signaling pathways. This comprehensive mechanism offers a foundation for further experimental validation.

Swaying the advantage: multifaceted functions of inflammasomes in adaptive immunity

Eukaryotic cells are equipped with cytoplasmic sensors that recognize diverse pathogen- or danger-associated molecular patterns. In cells of the myeloid lineage, activation of these sensors leads to the assembly of a multimeric protein complex, called the inflammasome, that culminates in the production of inflammatory cytokines and pyroptosis. Recently, investigation of the inflammasomes in lymphocytes led to the discovery of functional pathways that were initially believed to be confined to the innate arm of the immune system. Thus, the adapter protein apoptosis-associated speck-like protein containing a CARD (ASC) was documented to play a critical role in antigen uptake by dendritic cells, and regulation of T- and B-cell motility at several stages, and absent in melanoma 2 (AIM2) was found to act as a modulator of regulatory T-cell differentiation. Remarkably, NLRP3 was demonstrated to act as a transcription factor that controls Th2 cell polarization, and as a negative regulator of regulatory T-cell differentiation by limiting Foxp3 expression. In B lymphocytes, NLRP3 plays a role in the transcriptional network that regulates B-cell development and homing, and its activation is essential for germinal center formation and maturation of high-affinity antibody responses. Such recently discovered inflammasome-mediated functions in T and B lymphocytes offer multiple cross-talk opportunities for the innate and adaptive arms of the immune system. A better understanding of the dialog between inflammasomes and intracellular components could be beneficial for therapeutic purposes in restoring immune homeostasis and mitigating inflammation in a wide range of disorders.

Serum Uric Acid Associates with Systemic Complement C3 Activation in Severe ANCA-Associated Renal Vasculitides

Involvement of the complement system is key to the pathogenesis of antineutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis, but immunometabolic implications, especially on serum uric acid (UA) levels, still need to be elucidated. A total of 34 patients with biopsy-proven ANCA-associated renal vasculitis between 2015 and 2020 were retrospectively enrolled. Serum UA levels were correlated with clinical and histopathological characteristics, separated for critically ill (CI, n = 19), myeloperoxidase (MPO)-ANCA (n = 21) and proteinase 3 (PR3)-ANCA (n = 13) subgroups. We here identified inverse correlations of serum UA levels and complement C3 levels in the total cohort (p = 0.005) and the CI subgroup (p < 0.001). Intrarenal complement C4d deposition in venules correlated with serum UA levels in the total cohort (p = 0.007) and in the CI subgroup (p = 0.016). Significant associations of serum UA levels and tubulitis in areas of scarred cortex (t-IFTA) were identified in the total cohort (p = 0.008), and both subgroups of CI (p = 0.034) and MPO-ANCA (p = 0.029). In PR3-ANCA, interstitial fibrosis (ci) was observed as the strongest association with serum UA levels (p = 0.022). Our observations broaden our current understanding of contributory metabolic factors that influence the initial disease course in ANCA-associated renal vasculitis.

The dysregulation of immune cells induced by uric acid: mechanisms of inflammation associated with hyperuricemia and its complications

Changes in lifestyle induce an increase in patients with hyperuricemia (HUA), leading to gout, gouty arthritis, renal damage, and cardiovascular injury. There is a strong inflammatory response in the process of HUA, while dysregulation of immune cells, including monocytes, macrophages, and T cells, plays a crucial role in the inflammatory response. Recent studies have indicated that urate has a direct impact on immune cell populations, changes in cytokine expression, modifications in chemotaxis and differentiation, and the provocation of immune cells by intrinsic cells to cause the aforementioned conditions. Here we conducted a detailed review of the relationship among uric acid, immune response, and inflammatory status in hyperuricemia and its complications, providing new therapeutic targets and strategies.

Hyperuricemia remodels the serum proteome toward a higher inflammatory state

Gout is an autoinflammatory disease triggered by a complex innate immune response to MSU crystals and inflammatory triggers. While hyperuricemia is an obligatory risk factor for the development of gout, the majority of individuals with hyperuricemia never develop gout but have an increased risk of developing cardiometabolic disorders. Current management of gout aims at MSU crystal dissolution by lowering serum urate. We apply a targeted proteomic analysis, using Olink inflammation panel, to a large group of individuals with gout, asymptomatic hyperuricemia, and normouricemic controls, and we show a urate-driven inflammatory signature. We add in vivo evidence of persistent immune activation linked to urate exposure and describe immune pathways involved in the pathogenesis of gout. Our results support a pro-inflammatory effect of asymptomatic hyperuricemia and pave the way for new research into targetable mechanisms in gout and cardiometabolic complications of asymptomatic hyperuricemia.

Self-assembled ferritin nanoparticles displaying PcrV and OprI as an adjuvant-free Pseudomonas aeruginosa vaccine

Introduction

Serious infections of Pseudomonas aeruginosa (PA) in hospitals and the emergence and increase of multidrug resistance have raised an urgent need for effective vaccines. However, no vaccine has been approved to date. One possible reason for this is the limited immune response due to the lack of an efficient delivery system. Self-assembled ferritin nanoparticles are good carriers of heterogeneous antigens, which enhance the activation of immunological responses.

Methods

In this study, two well-studied antigen candidates, PcrV and OprI, were selected and connected to the ferritin nanoparticle by the Spytag/SpyCatcher system to generate the nanovaccine rePO-FN.

Results

Compared to recombinant PcrV-OprI formulated with aluminum adjuvants, intramuscular immunization with adjuvant-free rePO-FN induced quick and efficient immunity and conferred protection against PA pneumonia in mice. In addition, intranasal immunization with adjuvant-free rePO-FN enhanced protective mucosal immunity. Moreover, rePO-FN exhibited good biocompatibility and safety.

Discussion

Our results suggest that rePO-FN is a promising vaccine candidate, as well as, provide additional evidence for the success of ferritin-based nanovaccines.

Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases

Natural soluble antagonist and decoy receptor on the surface of the cell membrane are evolving as crucial immune system regulators as these molecules are capable of recognizing, binding, and neutralizing (so-called inhibitors) their targeted ligands. Eventually, these soluble antagonists and decoy receptors terminate signaling by prohibiting ligands from connecting to their receptors on the surface of cell membrane. Interleukin-18 binding protein (IL-18BP) participates in regulating both Th1 and Th2 cytokines. IL-18BP is a soluble neutralizing protein belonging to the immunoglobulin (Ig) superfamily as it harbors a single Ig domain. The Ig domain is essential for its binding to the IL-18 ligand and holds partial homology to the IL-1 receptor 2 (IL-1R2) known as a decoy receptor of IL-1α and IL-1β. IL-18BP was defined as a unique soluble IL-18BP that is distinct from IL-18Rα and IL-18Rβ chain. IL-18BP is encoded by a separated gene, contains 8 exons, and is located at chr.11 q13.4 within the human genome. In this review, we address the difference in the biological activity of IL-18BP isoforms, in the immunity balancing Th1 and Th2 immune response, its critical role in autoimmune diseases, as well as current clinical trials of recombinant IL-18BP (rIL-18BP) or equivalent.

Additional Evidence for Commonalities between COVID-19 and Radiation Injury: Novel Insight into COVID-19 Candidate Drugs

COVID-19 is a challenge to biosecurity and public health. The speed of vaccine development lags behind that of virus evolution and mutation. To date, no agent has been demonstrated to be fully effective against COVID-19. Therefore, it remains of great urgency to rapidly develop promising therapeutic and diagnostic candidates. Intriguingly, mounting evidence hints at parallel etiologies between SARS-CoV-2 infection and radiation injury. Herein, from the perspectives of immunogenic pathway activation and metabolic alterations, we provide novel evidence of commonalities between these two pathological conditions based on the most recent findings. Since numerous agents have been developed to prevent or reverse radiation injury in the past 70 years to ensure nuclear safety, we also advocate investigating the promising function of radioprotectors and radiomitigators against COVID-19 in clinical settings.

3,4-Methylenedioxy-β-Nitrostyrene Alleviates Dextran Sulfate Sodium–Induced Mouse Colitis by Inhibiting the NLRP3 Inflammasome

Inflammatory bowel disease (IBD) has been reported to be associated with NLRP3 inflammasome activation. Therefore inhibiting inflammasome activation could be a new approach to treat IBD. Inflammasome inhibitors NLRP3-IN-2, JC124, and 3,4-methylenedioxy-β-nitrostyrene (MNS) were previously reported to exert anti-inflammatory effects in various disease models but not in the dextran sulfate sodium (DSS)–induced colitis model. Here, we showed that MNS was more efficient in inhibiting the secretion of interleukin-1β (IL-1β) by blocking oligomerization of apoptosis-associated speck-like protein (ASC) than NLRP3-IN-2 and JC124. To investigate the protective effects of MNS on enteritis, we administered intragastric MNS to DSS-induced colitis mice. The results demonstrated that MNS attenuated DSS-induced body weight loss, colon length shortening, and pathological damage. In addition, MNS inhibited the infiltration of macrophages and inflammatory cells and reduced IL-1β and IL-12p40 pro-inflammatory cytokines but had no significant effect on tumor necrosis factor α (TNF-α) and IL-6. Furthermore, we also found that the differentiation of IL-17A⁺interferon-γ (IFN-γ)⁺CD4⁺ T cell was decreased in the colon after MNS treatment, which might be mediated by IL-1β, etc. cytokine release. Taken together, MNS alleviated DSS-induced intestinal inflammation by inhibiting NLRP3 inflammasome activation, which may function as an effective therapeutic for IBD.

Serum Uric Acid as a Diagnostic Biomarker for Rheumatoid Arthritis-Associated Interstitial Lung Disease

Previous studies have suggested a correlation between uric acid (UA) and lung lesion in some diseases. However, it remains unknown whether UA contributes to the lung injury in rheumatoid arthritis (RA). Our study aimed to investigate the clinical value of the UA level in the severity of rheumatoid arthritis-associated interstitial lung disease (RA-ILD). We measured UA in serum and bronchoalveolar lavage fluid (BALF), and UA levels of subjects were compared. As for the role of UA on ILD, we incubated A549 cells with UA and the expression of EMT markers was measured by immunofluorescence staining. The concentrations and messenger RNA expression of IL-1, IL-6, and transforming growth factor-β (TGF-β) were measured by ELISA and RT-PCR, respectively. We observed that serum UA levels in RA were significantly higher than those in controls. And, higher UA was measured in both serum and BALF of patients with RA-ILD, particularly those with interstitial pneumonia (UIP) pattern. Additionally, the correlation of the serum and BALF UA levels with serum KL-6, a biomarker of ILDs, in RA was significant (r = 0.44, p < 0.01; r = 0.43, p < 0.01). And, the negative correlations of UA, in both serum and BALF, with forced vital capacity (r =  -0.61, p < 0.01; r =  -0.34, p < 0.01) and diffusing capacity for carbon monoxide (r =  -0.43, p < 0.01; r =  -0.30, p < 0.01) were measured in patients. In the ROC curve analysis, the AUC value of UA for RA-ILD was 0.744 (95% CI: 0.69-0.80; p < 0.01), and the AUC of serum UA for predicting UIP pattern of patients with RA-ILD was 0.845 (95% CI: 0.78-0.91; p < 0.01), which showed the significance of the UA in clinical settings. Also, the in vitro experiment showed that UA induced epithelial-to-mesenchymal transition (EMT) and production of IL-1, IL-6, and TGF-β in A549 cells. Therefore, the elevated UA levels may be a diagnostic marker in RA-ILD, particularly RA-UIP.

Probing Inflammasome Activation in Atherosclerosis

Atherosclerosis is driven by chronic inflammation in all stages of the disease. Inflammation is fueled by elevated levels of pro-inflammatory cytokines. Interleukins (IL) are cytokines of particular importance in atherosclerosis, due to their key involvement in various pro-atherogenic processes, including infiltration of immune cells to the lesion, stimulation of the production of other pro-inflammatory mediators by other sources, and generation of lipid laden foam cells, all of which contribute to plaque development and progression. Various stimuli that are abundant in atherosclerotic plaques, including oxidized low-density lipoprotein, cholesterol crystals and reactive oxygen species can trigger inflammasome activation. Importantly, activation of the nucleotide oligomerization domain leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) inflammasome activates the caspase-1 protease and results in the generation and release of potent pro-inflammatory cytokines, IL-1β and IL-18. Both cytokines are influential in driving chronic inflammation and atherogenesis. This chapter describes the use of enzyme-linked immunosorbent assay (ELISA) and Western blot to quantify these cytokines in cell supernatant and lysate respectively, after stimulating inflammasome activation in cultured cells.

Effects of Dietary Astragalus Polysaccharide Supplementation on the Th17/Treg Balance and the Gut Microbiota of Broiler Chickens Challenged With Necrotic Enteritis

This study aimed to investigate the effects of dietary astragalus polysaccharide (APS) supplementation on the immune function, gut microbiota and metabolism of broiler chickens challenged with necrotic enteritis (NE). Two hundred forty Arbor Acres broiler chicks (one day old) were randomly assigned using a 2 × 2 factorial arrangement into two groups fed different levels of dietary APS (0 or 200 ppm of diet) and two disease challenge groups (control or NE challenged). The results showed that NE infection significantly increased FCR, mortality rate, Th17/Treg (Th17 cells% in blood and ileum, Th17/Treg, IL-17 and IL-17/IL-10 in blood), NO, lysozyme activity and IL-1β in blood, intestinal immune cell proportion and activity (Tc%, Treg% and monocyte phagocytic activity in ileum), intestinal inflammatory cytokines (TLR2, NF-κB, TNF-α and IL- 6) gene expression levels, and the number of Clostridium perfringens in cecum. NE infection significantly reduced body weight gain, thymus index, lymphocyte proliferation activity in blood and ileum, villus height and V/C in jejunum, Th cells% and Mucin2 gene expression in ileum. Dietary APS supplementation significantly increased body weight, feed intake, proportion of immune cells (T cells in blood and Tc, Treg in ileum), lymphocyte proliferation activity, V/C in jejunum, and ZO-1 gene expression in ileum. Dietary APS supplementation significantly reduced FCR and mortality rate, Th17/Treg, Th17%, intestinal pathology scores, intestinal inflammatory cytokine gene expression levels, and the number of Clostridium perfringens in cecum. In addition, broilers challenged with NE significantly increased Staphylococcus and Turicibacter and reduced α diversity of microbiota in ileum. Dietary APS supplementation significantly increased α diversity, Romboutsia, Halomonas, propionic acid, butyric acid, formononetin, taurine, cholic acid and equol and downregulated uric acid, L-arginine and serotonin in ileum. Spearman’s correlation analysis revealed that Romboutsia, Turicibacter, Staphylocpccus, Halomonas, Streptococcus, Escherichia-Shigella, Prevotella, uric acid, L-arginine, jerivne, sodium cholate and cholic acid were related to inflammation and Th17/Treg balance. In conclusion, APS alleviated intestinal inflammation in broilers challenged with NE probably by regulating intestinal immune, Th17/Treg balance, as well as intestinal microbiota and metabolites.

DAMPs are able to skew CD4+ T cell subsets and increase the inflammatory profile in pregnant women with preeclampsia

Preeclampsia (PE) is characterized by abnormal activation of the immune system. The intense systemic inflammatory reaction, could be related to the presence of molecules released after cell stress or death, that are capable of inducing inflammation and are known as damage-associated molecular patterns (DAMP). This study evaluated the profile of T cells through the analysis of transcription factors and the cytokines produced after culture with or without DAMPs: heat shock protein 70 (Hsp70), hyaluronan (HA) and monosodium urate (MSU). Twenty pregnant women with PE, 20 normotensive (NT) pregnant women and 20 non-pregnant (NP) women were studied. The results showed polarization toward Th1/Th17 and a decrease in Th2/Treg profiles in preeclamptic women associated with elevated levels of TNF, IFN-γ, and IL-17A and diminished levels of TGF-β1 and IL-10 when compared to the normotensive group. In addition, preeclamptic women had a higher percentage of cells co-expressing T-bet/GATA-3 and T-bet/RORγt and fewer T-bet/FoxP3 cells when compared to normotensive group. MSU induced an increase in IFN-γ and IL-22 in all studied groups. MSU, HA, and Hsp70 induced significant higher production of TNF in the PE and NP groups. The PE group showed elevated levels of TGF-β1 after incubation with MSU, HA, and Hsp70, whereas HA and Hsp70 decreased TGF-β1 production in NT group. The results suggest that these alarmins may play a role in the activation of innate and adaptive immune systems by skewing CD4 + T cells and increasing the release of inflammatory cytokines, thereby contributing to the pathogenesis of this important syndrome.

Centrality of Myeloid-Lineage Phagocytes in Particle-Triggered Inflammation and Autoimmunity

Exposure to exogenous particles found as airborne contaminants or endogenous particles that form by crystallization of certain nutrients can activate inflammatory pathways and potentially accelerate autoimmunity onset and progression in genetically predisposed individuals. The first line of innate immunological defense against particles are myeloid-lineage phagocytes, namely macrophages and neutrophils, which recognize/internalize the particles, release inflammatory mediators, undergo programmed/unprogrammed death, and recruit/activate other leukocytes to clear the particles and resolve inflammation. However, immunogenic cell death and release of damage-associated molecules, collectively referred to as "danger signals," coupled with failure to efficiently clear dead/dying cells, can elicit unresolved inflammation, accumulation of self-antigens, and adaptive leukocyte recruitment/activation. Collectively, these events can promote loss of immunological self-tolerance and onset/progression of autoimmunity. This review discusses critical molecular mechanisms by which exogenous particles (i.e., silica, asbestos, carbon nanotubes, titanium dioxide, aluminum-containing salts) and endogenous particles (i.e., monosodium urate, cholesterol crystals, calcium-containing salts) may promote unresolved inflammation and autoimmunity by inducing toxic responses in myeloid-lineage phagocytes with emphases on inflammasome activation and necrotic and programmed cell death pathways. A prototypical example is occupational exposure to respirable crystalline silica, which is etiologically linked to systemic lupus erythematosus (SLE) and other human autoimmune diseases. Importantly, airway instillation of SLE-prone mice with crystalline silica elicits severe pulmonary pathology involving accumulation of particle-laden alveolar macrophages, dying and dead cells, nuclear and cytoplasmic debris, and neutrophilic inflammation that drive cytokine, chemokine, and interferon-regulated gene expression. Silica-induced immunogenic cell death and danger signal release triggers accumulation of T and B cells, along with IgG-secreting plasma cells, indicative of ectopic lymphoid tissue neogenesis, and broad-spectrum autoantibody production in the lung. These events drive early autoimmunity onset and accelerate end-stage autoimmune glomerulonephritis. Intriguingly, dietary supplementation with ω-3 fatty acids have been demonstrated to be an intervention against silica-triggered murine autoimmunity. Taken together, further insight into how particles drive immunogenic cell death and danger signaling in myeloid-lineage phagocytes and how these responses are influenced by the genome will be essential for identification of novel interventions for preventing and treating inflammatory and autoimmune diseases associated with these agents.

Uric acid as a prognostic factor and critical marker of COVID-19

The purpose of this study is to explore whether uric acid (UA) can independently act as a prognostic factor and critical marker of the 2019 novel corona virus disease (COVID-19). A multicenter, retrospective, and observational study including 540 patients with confirmed COVID-19 was carried out at four designated hospitals in Wuhan. Demographic, clinical, laboratory data were collected and analyzed. The primary end point was in-hospital death of patients with COVID-19. The concentration of admission UA (adUA) and the lowest concentration of uric acid during hospitalization (lowUA) in the dead patients were significantly lower than those in the survivors. Multivariate logistic regression analysis showed the concentration of lowUA (OR 0.986, 95% CI 0.980-0.992, p < 0.001) was able to independently predict the risk of in-hospital death. The mean survival time in the low-level group of lowUA was significantly lower than other groups. When lowUA was ≤ 166 µmol/L, the sensitivity and specificity in predicting hospital short-term mortality were 76.9%, (95% CI 68.5-85.1%) and 74.9% (95% CI 70.3-78.9%). This retrospective study determined that the lowest concentration of UA during hospitalization can be used as a prognostic indicator and a marker of disease severity in severe patients with COVID-19.

Clinical and immunologic differences in cellulitis vs. pseudocellulitis

Introduction: The immunologic mechanisms between cellulitis and pseudocellulitis differ greatly, even though their clinical presentations may overlap.Areas covered: This article discusses cellulitis and common entities within the pseudocellulitis spectrum including acute lymphedema, superficial venous thrombosis, allergic contact dermatitis, lipodermatosclerosis, stasis dermatitis, erythema nodosum, cutaneous gout, and bursitis. The literature search was conducted from PubMed search engine between March and May 2021.Expert commentary: While immunologic differences in cellulitis and the various entities of pseudocellulitis are clear, there is a practice gap in applying these differences to the clinic and hospital setting. Further, existing studies are weakened by the lack of a gold-standard diagnosis in this disease category. Additional work is necessary in developing a gold-standard for the diagnosis and secondly, to project these immunologic differences as biomarkers to differentiate sterile inflammation from a potential life threatening bacterial or fungal infection.

Inflammasomes in dendritic cells: Friend or foe?

Inflammasomes are cytosolic multiprotein complexes that crucially contribute to host defense against pathogens but are also involved in the pathogenesis of autoinflammatory diseases. Inflammasome formation leads to activation of effector caspases (caspase-1, 4, 5, or 11), the proteolytic maturation of IL-1β and IL-18 as well as cleavage of the pore-forming protein Gasdermin D. Dendritic cells are major regulators of immune responses as they bridge innate and adaptive immunity. We here summarize the current knowledge on inflammasome expression and formation in murine bone marrow-, human monocyte-derived as well as murine and human primary dendritic cells. Further, we discuss both, the beneficial and detrimental, involvement of inflammasome activation in dendritic cells in cancer, infections, and autoimmune diseases. As inflammasome activation is typically accompanied by Gasdermin d-mediated pyroptosis, which is an inflammatory form of programmed cell death, inflammasome formation in dendritic cells seems ill-advised. Therefore, we propose that hyperactivation, which is inflammasome activation without the induction of pyroptosis, may be a general model of inflammasome activation in dendritic cells to enhance Th1, Th17 as well as cytotoxic T cell responses.

Development of a Chimeric Vaccine Against Pseudomonas aeruginosa Based on the Th17-Stimulating Epitopes of PcrV and AmpC

Pulmonary infection caused by Pseudomonas aeruginosa (PA) has created an urgent need for an efficient vaccine, but the protection induced by current candidates is limited, partially because of the high variability of the PA genome. Antigens targeting pulmonary Th17 responses are able to provide antibody-independent and broad-spectrum protection; however, little information about Th17-stimulating antigens in PA is available. Herein, we identified two novel PA antigens that effectively induce Th17-dependent protection, namely, PcrV (PA1706) and AmpC (PA4110). Compared to intramuscular immunization, intranasal immunization enhanced the protection of rePcrV due to activation of a Th17 response. The Th17-stimulating epitopes of PcrV and AmpC were identified, and the recombinant protein PVAC was designed and generated by combining these Th17-stimulating epitopes. PVAC was successfully produced in soluble form and elicited broad protective immunity against PA. Our results provide an alternative strategy for the development of Th17-based vaccines against PA and other pathogens.

Age-Specific Imbalance of Circulating Tfh Cell Subsets and Its Association With Gout-Targeted Kidney Impairment

Objective

Gout is a chronic disease characterized by the deposition of monosodium urate (MSU) crystals in tissue. Study with a focus on adaptive immune response remains to be understood although innate immune response has been reported extensively in gout etiology. Our study attempted to investigate the association of gout-related immune cell imbalance with clinical features and comorbidity with renal impairment and the implicated pathogenesis via the assessment of T and B cell subsets in different activity phases or with immune effects combined with the analyses of clinical parameters.

Methods

Fifty-eight gout patients and 56 age- and sex-matched healthy individuals were enrolled. To learn the roles of circulating T cells, a lymphocyte profile incorporating 32 T cell subsets was tested from isolated freshly peripheral blood monocyte cells (PBMCs) with multiple-color flow cytometry. Furthermore, the collected clinical features of participants were used to analyze the characteristics of these differential cell subsets. Stratified on the basis of the level of creatinine (Cr, enzymatic method), all patients were categorized into Cr^low (Cr ≤ 116 μmol/L) and Cr^hi (Cr > 116 μmol/L) groups to exploit whether these gout-associated T cell subsets were functional in gout-targeted kidney dysfunction. The differentiation of B cells was investigated in gout patients.

Results

Our results show that CD 4⁺ T cells, Th2 cells, and Tc2 cells were upregulated, whereas Tc17 cells were downregulated. Tfh cells skewed toward the polarization of Tfh2 cells. Specifically, Tfh2 cells increased, but Tfh1 cells decreased, accompanied with aging for gout patients, suggesting that age might trigger the skewing of Tfh1/Tfh2 cell subsets to influence gout development. Moreover, Tfh2 cells were connected to renal dysfunction as well. No alterations of B cell subsets were observed in patients when compared to controls.

Conclusions

Our data demonstrate age-specific dysfunctions of Tfh1/2 cells in gout occurrence, and Tfh2 cell upregulation is associated with gout-targeted renal dysfunction. However, Tfh2 cells may function in auto-inflammatory gout independent of helping B differentiation, and an in-depth study remains to be conducted.

sLeX Expression Delineates Distinct Functional Subsets of Human Blood Central and Effector Memory T Cells

Sialyl Lewis X (sLeX) regulates T cell trafficking from the vasculature into skin and sites of inflammation, thereby playing a critical role in immunity. In healthy persons, only a small proportion of human blood T cells express sLeX, and their function is not fully defined. Using a combination of biochemical and functional studies, we find that human blood sLeX+CD4+T cells comprise a subpopulation expressing high levels of Th2 and Th17 cytokines, chemokine receptors CCR4 and CCR6, and the transcription factors GATA-3 and RORγT. Additionally, sLeX+CD4+T cells exclusively contain the regulatory T cell population (CD127lowCD25high and FOXP3+) and characteristically display immune-suppressive molecules, including the coinhibitor receptors PD-1 and CTLA-4. Among CD8+T cells, sLeX expression distinguishes a subset displaying low expression of cytotoxic effector molecules, perforin and granzyme β, with reduced degranulation and CD57 expression and, consistently, marginal cytolytic capacity after TCR engagement. Furthermore, sLeX+CD8+T cells present a pattern of features consistent with Th cell-like phenotype, including release of pertinent Tc2 cytokines and elevated expression of CD40L. Together, these findings reveal that sLeX display is associated with unique functional specialization of both CD4+ and CD8+T cells and indicate that circulating T cells that are primed to migrate to lesional sites at onset of inflammation are not poised for cytotoxic function.

Role of T cells in the pathogenesis and treatment of gout

Though macrophages and neutrophils are considered to be the principal immune cells involved in gout inflammation, recent studies highlight an emerging role of T cell subsets in the pathogenesis of gout. Some studies found that abnormal functions of several T cell subsets and aberrant expressions of their signature cytokines existed in gouty arthritis. Additionally, recent studies also suggested that therapeutic strategies by targeting pro-inflammatory T cell subsets or their related cytokines could ameliorate monosodium urate (MSU) crystals-induced arthritis in mice. The important role of T cells in gouty arthritis may provide some explanation for the absence of acute gout attacks among individuals with severe hyperuricemia or clinical evidence of MSU crystals deposition. Nevertheless, the molecular mechanisms underlying the role of those T cell subsets in gouty arthritis and their role in the initiation, progression and resolution of gouty arthritis are largely elusive, which need to be elaborated in future research. Uncovering the role of those T cell subsets in gout may transform our understanding of gout and facilitate new promising preventive or therapeutic strategies for gouty arthritis.

Research Advances in the Mechanisms of Hyperuricemia-Induced Renal Injury

Uric acid is the end product of purine metabolism in humans, and its excessive accumulation leads to hyperuricemia and urate crystal deposition in tissues including joints and kidneys. Hyperuricemia is considered an independent risk factor for cardiovascular and renal diseases. Although the symptoms of hyperuricemia-induced renal injury have long been known, the pathophysiological molecular mechanisms are not completely understood. In this review, we focus on the research advances in the mechanisms of hyperuricemia-caused renal injury, primarily on oxidative stress, endothelial dysfunction, renal fibrosis, and inflammation. Furthermore, we discuss the progress in hyperuricemia management.

Gout: a disease involved with complicated immunoinflammatory responses: a narrative review

Gout is a disease with acute and/or chronic inflammation and tissue damage induced by the precipitation of monosodium urate crystal (MSU) crystals in bone joints, kidneys, and subcutaneous sites. In recent years, with the continuous research on gout animal models and patient clinical investigations, the mechanism of inflammation activation of gout has been further discovered. Studies have shown that pro-inflammatory factors such as interleukin (IL)-1β, IL-8 and IL-17, NLRP3 inflammasome, and tumor necrosis factor alpha (TNF-α), anti-inflammatory factors such as IL-10, IL-37 are all involved in the MSU-induced gout inflammatory process. And the immune cells in gout, including neutrophils, monocytes/macrophages, and lymphocytes, all play important roles in the pathogenesis of gout. In this review, we mainly emphasize the understanding of various cytokines, inflammasome, and immune cells involved in the onset of gout, in order to provide a systematic and theoretical basis for the novel exploration of inflammatory therapeutic targets for gout.

Uric acid and inflammation in kidney disease

Asymptomatic hyperuricemia is frequently observed in patients with kidney disease. Although a substantial number of epidemiologic studies have suggested that an elevated uric acid level plays a causative role in the development and progression of kidney disease, whether hyperuricemia is simply a result of decreased renal excretion of uric acid or is a contributor to kidney disease remains a matter of debate. Over the last two decades, multiple experimental studies have expanded the knowledge of the biological effects of uric acid beyond its role in gout. In particular, uric acid induces immune system activation and alters the characteristics of resident kidney cells, such as tubular epithelial cells, endothelial cells, and vascular smooth muscle cells, toward a proinflammatory and profibrotic state. These findings have led to an increased awareness of uric acid as a potential and modifiable risk factor in kidney disease. Here, we discuss the effects of uric acid on the immune system and subsequently review the effects of uric acid on the kidneys mainly in the context of inflammation.

Fructose metabolism as a common evolutionary pathway of survival associated with climate change, food shortage and droughts

Mass extinctions occur frequently in natural history. While studies of animals that became extinct can be informative, it is the survivors that provide clues for mechanisms of adaptation when conditions are adverse. Here, we describe a survival pathway used by many species as a means for providing adequate fuel and water, while also providing protection from a decrease in oxygen availability. Fructose, whether supplied in the diet (primarily fruits and honey), or endogenously (via activation of the polyol pathway), preferentially shifts the organism towards the storing of fuel (fat, glycogen) that can be used to provide energy and water at a later date. Fructose causes sodium retention and raises blood pressure and likely helped survival in the setting of dehydration or salt deprivation. By shifting energy production from the mitochondria to glycolysis, fructose reduced oxygen demands to aid survival in situations where oxygen availability is low. The actions of fructose are driven in part by vasopressin and the generation of uric acid. Twice in history, mutations occurred during periods of mass extinction that enhanced the activity of fructose to generate fat, with the first being a mutation in vitamin C metabolism during the Cretaceous-Paleogene extinction (65 million years ago) and the second being a mutation in uricase that occurred during the Middle Miocene disruption (12-14 million years ago). Today, the excessive intake of fructose due to the availability of refined sugar and high-fructose corn syrup is driving 'burden of life style' diseases, including obesity, diabetes and high blood pressure.

At the crossroads of gout and psoriatic arthritis: "psout"

Psoriatic arthritis and gout are frequently encountered conditions sharing a number of common risk factors, which render their independent study difficult. Epidemiological studies have demonstrated a strong link between these diseases, suggesting the presence of underlying, intertwined pathophysiological mechanisms that currently remain unknown. Indeed, sodium urate crystals could play a pathogenic role in psoriasis and psoriatic arthritis. In daily practice, the distinction between psoriatic arthritis associated with hyperuricemia and a gouty arthropathy with psoriasis is complex. Several common pathogenic features suggest a more intricate relationship than their mere coexistence in the same patient. Thus, the concurrence of these two diseases should be seen as a novel overlap syndrome, at the boundary between inflammatory and metabolic rheumatism. The present update aims to clarify the determinants of the link and to define this new nosological entity. Its recognition could have therapeutic implications that appear essential for treatment optimization in a personalized setting.Key Points• What is already known about this subject? Psoriatic arthritis (PsA) and gout have strong interconnections, including comorbidities and pathophysiology. One must note that confounding clinical symptoms and radiological signs of PsA and gout are similar and difficult to differentiate in patients whose radiological lesions become too advanced to be differentiated or with less clearly defined phenotypes.• What does this study add? The pathogenic role of chronic hyperuricemia in the development and maintenance of PsA is based on epidemiological, clinical, and fundamental arguments and hence does not appear fortuitous. These two pathological processes can influence each other.• How might this impact on clinical practice? This new line of thinking regarding the convergence of gout and PsA, involving the role of urate crystals, could prompt a potential new approach to treatment (urate-lowering therapy) among patients with active/refractory PsA.

Leptin facilitates the differentiation of Th17 cells from MRL/Mp-Fas lpr lupus mice by activating NLRP3 inflammasome

Both NLRP3 inflammasome and Th17 cells play important roles in the pathogenesis of systemic lupus erythematosus (SLE). Here we tried to investigate whether leptin promotes the differentiation of Th17 cells from lupus mice by activating the NLRP3 inflammasome. Th17 cells induced from MRL/Mp-Fas lpr mice splenocytes under Th17 polarizing condition were treated with leptin at scalar doses during the last 18 h of culture. The mRNA levels of IL-17A, IL-17F, RORγt, IL-1β, IL-18, NLRP3, ASC, and IL-1R1 were detected by quantitative PCR. IL-17A, IL-17F, IL-1β, and IL-18 were tested by ELISA, while the activity of caspase-1 and number of Th17 cells were counted by flow cytometry before/after inhibition of the NLRP3 inflammasome. We found that leptin pushed up the expression of IL-17A, IL-17F, NLRP3, and IL-1β and increased the number of Th17 cells in lupus mice, while the expression of IL-17A, RORγt, and IL-1β and the number of Th17 cells were decreased after inhibition of the NLRP3 inflammasome. Leptin promoted the differentiation of Th17 cells from lupus mice by activating the NLRP3 inflammasome.

A comparative study on the mechanisms of innate immune responses in mice induced by Alum and Actinidia eriantha polysaccharide

The innate immune mechanisms by which adjuvants enhance the potency and protection of vaccine remain at cellular level, but the molecular mechanisms, especially in vivo, are ill-identified. Actinidia eriantha polysaccharide (AEPS) is a potent adjuvant with dual Th1 and Th2 potentiating activity, while Alum elicits a strict Th2 response. The current experiments were designed to compare the innate immune responses in the peritoneal cavity of mice induced by two adjuvants and explore their molecular mechanisms using gene expression microarray including long noncoding RNAs (lncRNAs). AEPS induced the recruitment of monocytes, neutrophils and dendritic cells. However, Alum recruited neutrophils and eosinophils. AEPS and Alum specifically induced the differential expression of 546 and 922 genes in peritoneal cells, respectively. AEPS induced higher mRNA expression of CCL2, CCL3, CCL4, CCL7, CXCL2, CXCL3, CXCL5, CXCL10, IL-12β, and IL-23α in immune effector process, while Alum tended to Th17 response mRNAs such as IL-7A, IL-17F and IL-17RA. Furthermore, a robust adjuvant-specific expression pattern of lncRNAs was found in above mentioned biological processes, suggesting the involvement of lncRNAs in immune responses induced by AEPS and Alum. This study led to a better understanding of different molecular mechanisms of adjuvants and benefited the rational design of effective vaccines.

The Inflammasome Adaptor ASC Intrinsically Limits CD4+ T-Cell Proliferation to Help Maintain Intestinal Homeostasis

The inflammasome is a multi-protein complex that mediates proteolytic cleavage and release of the pro-inflammatory cytokines IL-1β and IL-18, and pyroptosis—a form of cell death induced by various pathogenic bacteria. Apoptosis-associated speck-like protein containing a CARD (ASC) has a pivotal role in inflammasome assembly and activation. While ASC function has been primarily implicated in innate immune cells, its contribution to lymphocyte biology is unclear. Here we report that ASC is constitutively expressed in naïve CD4⁺ T cells together with the inflammasome sensor NLRP3 and caspase-1. When adoptively transferred in immunocompromised Rag1^−/− mice, Asc^−/− CD4⁺ T cells exacerbate T-cell-mediated autoimmune colitis. Asc^−/− CD4⁺ T cells exhibit a higher proliferative capacity in vitro than wild-type CD4⁺ T cells. The increased expansion of Asc^−/− CD4⁺ T cells in vivo correlated with robust TCR-mediated activation, inflammatory activity, and higher metabolic profile toward a highly glycolytic phenotype. These findings identify ASC as a crucial intrinsic regulator of CD4⁺ T-cell expansion that serves to maintain intestinal homeostasis.

Male asymptomatic hyperuricemia patients display a lower number of NKG2D+ NK cells before and after a low-purine diet

BACKGROUND

Aberrant activation of the immune system has been reported in asymptomatic hyperuricemia (HUA) patients. However, very few studies have elucidated the role of natural killer (NK) cells in this disease.

METHODS

In this study, we evaluated the relationship between NK cells and HUA in 16 control subjects and 20 patients, who were all on a low-purine diet. We analyzed the number of circulating NK cells, its subsets, interferon-γ, and CD107 NK cells, by flow cytometry, before and after 4 and 24 weeks of diet control. We also assessed the potential association of the NK cells with clinical measures.

RESULTS

The patients consistently had a lower number of NKG2D NK cells before and after low-purine diet, even the serum uric acid (SUA) levels <7 mg/dL after diet control. Moreover, a lower number of NK cells and a higher number of CD107a NK cells were observed on recruitment. Low-purine diet was benefit on the improvement of the SUA levels, body mass index (BMI), and the number and functions of NK cells. Furthermore, the number of CD3CD56 NK cells and NKG2D NK cells negatively correlated with the BMI before and after diet control.

CONCLUSION

The consistent lower number of NKG2D NK cells and correlated with BMI before and after low-purine diet may be involved in the occurrence and development of HUA.

Unraveling the enigma: elucidating the relationship between the physicochemical properties of aluminium-based adjuvants and their immunological mechanisms of action

Aluminium salts are by far the most commonly used adjuvants in vaccines. There are only two aluminium salts which are used in clinically-approved vaccines, Alhydrogel® and AdjuPhos®, while the novel aluminium adjuvant used in Gardasil® is a sulphated version of the latter. We have investigated the physicochemical properties of these two aluminium adjuvants and specifically in milieus approximating to both vaccine vehicles and the composition of injection sites. Additionally we have used a monocytic cell line to establish the relationship between their physicochemical properties and their internalisation and cytotoxicity. We emphasise that aluminium adjuvants used in clinically approved vaccines are chemically and biologically dissimilar with concomitantly potentially distinct roles in vaccine-related adverse events.

MiR-29b antagonizes the pro-inflammatory tumor-promoting activity of multiple myeloma-educated dendritic cells

Dendritic cells (DCs) have a key role in regulating tumor immunity, tumor cell growth and drug resistance. We hypothesized that multiple myeloma (MM) cells might recruit and reprogram DCs to a tumor-permissive phenotype by changes within their microRNA (miRNA) network. By analyzing six different miRNA-profiling data sets, miR-29b was identified as the only miRNA upregulated in normal mature DCs and significantly downregulated in tumor-associated DCs. This finding was validated in primary DCs co-cultured in vitro with MM cell lines and in primary bone marrow DCs from MM patients. In DCs co-cultured with MM cells, enforced expression of miR-29b counteracted pro-inflammatory pathways, including signal transducer and activator of transcription 3 and nuclear factor-κB, and cytokine/chemokine signaling networks, which correlated with patients' adverse prognosis and development of bone disease. Moreover, miR-29b downregulated interleukin-23 in vitro and in the SCID-synth-hu in vivo model, and antagonized a Th17 inflammatory response. All together, these effects translated into strong anti-proliferative activity and reduction of genomic instability of MM cells. Our study demonstrates that MM reprograms the DCs functional phenotype by downregulating miR-29b whose reconstitution impairs DCs ability to sustain MM cell growth and survival. These results underscore miR-29b as an innovative and attractive candidate for miRNA-based immune therapy of MM.

NLRP3 inflammasome pathways in atherosclerosis

Atherosclerosis is the major cause of death and disability. Atherosclerotic plaques are characterized by a chronic sterile inflammation in the large blood vessels, where lipid-derived and damage-associated molecular patterns play important roles in inciting immune responses. Following the initial demonstration that NLR family Pyrin domain containing 3 (NLRP3) was important for atherogenesis, a substantial number of studies have emerged addressing the basic mechanisms of inflammasome activation and their relevance to atherosclerosis. In this review, we introduce the basic cellular and molecular mechanisms of NLRP3 inflammasome activation, and discuss the current findings and therapeutic strategies that target NLRP3 inflammasome activation during the development and progression of atherosclerosis.

Vaccination with a recombinant OprL fragment induces a Th17 response and confers serotype-independent protection against Pseudomonas aeruginosa infection in mice

Pseudomonas aeruginosa (PA) is the major causative agent of nosocomial infection. Despite of adequate use of antibiotics, it still represents a major challenge in controlling PA infection. The local pulmonary Th17 response plays an important protective role against PA infection. And the Th17-mediated protection is antibody independent, so we hypothesized that it would be an optimal strategy of a vaccine for PA control to induce an effective Th17 response. Herein we report the successful production of a recombinant fragment of the OprL (reOprL) of PA. Purified reOprL forms homogeneous monomers in solution and vaccination with reOprL elicited a remarkable Th17 response. In addition, reOprL vaccination conferred effective serotype-independent protection against PA infection, which relied on the Th17 response. Our data suggest that reOprL is a good candidate for the future development of Th17 immunity based PA vaccines.

Association between cytokine profile and transcription factors produced by T-cell subsets in early- and late-onset pre-eclampsia

Pre-eclampsia (PE) is an obstetric pathology characterized by abnormal activation of the innate and adaptive immune systems dependent on the imbalance of T helper subsets. The present study aimed to evaluate the gene and protein expression of T helper type 1 (Th1)/Th2/Th17/regulatory T (Treg) cell transcription factors in peripheral blood lymphocytes from pregnant women with PE employing quantitative RT-PCR and flow cytometry techniques, as well as the cytokine profile produced by these CD4+ T-cell subsets in the plasma of pregnant women with PE, classified as early-onset PE (n = 20), late-onset PE (n = 20) and normotensive pregnant women (n = 20). Results showed a higher percentage of CD4+ T cells expressing the RORc transcription factor (Th17) and a lower percentage of cells expressing FoxP3 (Treg) in women with early-onset PE compared with late-onset PE and normotensive groups. A lower gene expression of GATA-3 transcription factor was detected in cells of women with early-onset PE compared with the late-onset PE group. Endogenous plasma levels of interleukin-6 (IL-6), IL-17 and tumour necrosis factor-α were significantly higher in the early-onset PE group than in the late-onset PE and normotensive groups, whereas IL-4 (Th2 profile) and IL-22 (Th17 profile), were not significantly different between the studied groups. The endogenous levels of transforming growth factor-β and IL-10 were significantly lower in the pre-eclamptic than in the normotensive groups of the same gestational age, with a significant difference between early- and late-onset PE. The results show that in women with PE there is an imbalance between inflammatory and anti-inflammatory profiles in CD4+ T-cell subsets, with polarization to Th17 profiles in the early-onset PE, considered as the severe form of PE.

Suitable Concentrations of Uric Acid Can Reduce Cell Death in Models of OGD and Cerebral Ischemia-Reperfusion Injury

Cerebral infarction (CI) is a common clinical cerebrovascular disease, and to explore the pathophysiological mechanisms and seek effective treatment means are the hotspot and difficult point in medical research nowadays. Numerous studies have confirmed that uric acid plays an important role in CI, but the mechanism has not yet been clarified. When treating HT22 and BV-2 cells with different concentrations of uric acid, uric acid below 450 μM does not have significant effect on cell viability, but uric acid more than 500 μM can significantly inhibit cell viability. After establishing models of OGD (oxygen-glucose deprivation) with HT22 and BV-2 cells, uric acid at a low concentration (50 μM) cannot improve cell viability and apoptosis, and Reactive oxygen species (ROS) levels during OGD/reoxygenation; a suitable concentration (300 μM) of uric acid can significantly improve cell viability and apoptosis, and reduce ROS production during OGD/reoxygenation; but a high concentration (1000 μM) of uric acid can further reduce cell viability and enhance ROS production. After establishing middle cerebral artery occlusion of male rats with suture method, damage and increase of ROS production in brain tissue could be seen, and after adding suitable concentration of uric acid, the degree of brain damage and ROS production was reduced. Therefore, different concentrations of uric acid should have different effect, and suitable concentrations of uric acid have neuroprotective effect, and this finding may provide guidance for study on the clinical curative effect of uric acid.

Blood-borne phagocytes internalize urate microaggregates and prevent intravascular NETosis by urate crystals

Hyperuricemia is strongly linked to cardiovascular complications including atherosclerosis and thrombosis. In individuals with hyperuricemia, needle-shaped monosodium urate crystals (nsMSU) frequently form within joints or urine, giving rise to gouty arthritis or renal calculi, respectively. These nsMSU are potent instigators of neutrophil extracellular trap (NET) formation. Little is known on the mechanism(s) that prevent nsMSU formation within hyperuricemic blood, which would potentially cause detrimental consequences for the host. Here, we report that complement proteins and fetuins facilitate the continuous clearance by blood-borne phagocytes and resident macrophages of small urate microaggregates (UMA; <1 μm in size) that initially form in hyperuricemic blood. If this clearance fails, UMA exhibit bipolar growth to form typical full-sized nsMSU with a size up to 100 μm. In contrast to UMA, nsMSU stimulated neutrophils to release NETs. Under conditions of flow, nsMSU and NETs formed densely packed DNase I-resistant tophus-like structures with a high obstructive potential, highlighting the importance of an adequate and rapid removal of UMA from the circulation. Under pathological conditions, intravascularly formed nsMSU may hold the key to the incompletely understood association between NET-driven cardiovascular disease and hyperuricemia.

IL-18BP is decreased in osteoporotic women: Prevents Inflammasome mediated IL-18 activation and reduces Th17 differentiation

IL-18BP is a natural antagonist of pro-inflammatory IL-18 cytokine linked to autoimmune disorders like rheumatoid arthritis. However, its role in post menopausal osteoporosis is still unknown. In this study, we investigated the role of IL-18BP on murine osteoblasts, its effect on osteoblasts-CD4+ T cells and osteoblasts-CD11b+ macrophage co-culture. mIL-18BPd enhances osteoblast differentiation and inhibits the activation of NLRP3 inflammasome and caspase-1 which process IL-18 to its active form. Using estrogen deficient mice, we also determined the effect of mIL-18BP on various immune and skeletal parameters. Ovariectomized mice treated with mIL-18BPd exhibited decrease in Th17/Treg ratio and pro-inflammatory cytokines. mIL-18BPd treatment restored trabecular microarchitecture, preserved cortical bone parameters likely attributed to an increased number of bone lining cells and reduced osteoclastogenesis. Importantly, these results were corroborated in female osteoporotic subjects where decreased serum IL-18BP levels and enhanced serum IL-18 levels were observed. Our study forms a strong basis for using humanized IL-18BP towards the treatment of postmenopausal osteoporosis.

Cytokine Profile in Gout: Inflammation Driven by IL-6 and IL-18?

INTRODUCTION

Gout is considered to be an autoinflammatory disease and the presence of monosodium urate (MSU) crystals stimulates activation of NPRL3 inflammasome and subsequently caspase-1, generating production of active IL-1β and IL-18. However, the association between serum cytokines levels and clinical manifestations of the disease is not yet well understood. We evaluated the serum profile of proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17A, IL-18, IL-22, and IL-23) and described their relationship with clinical and laboratory data.

METHODOLOGY

Thirty-nine male patients with gout (GG) were assessed for clinical and laboratory variables and cytokine levels were measured by ELISA. For the purposes of comparison, 34 males with no previous history of arthritis were also included in the study (CG).

RESULTS

Seventeen participants (43%) exhibited active arthritis on evaluation. Levels of IL-18 were significantly higher in patients in relation to the CG (p = 0.0013). No statistically significant differences were found between the GG and CG for the other measured cytokines. There was a moderate correlation between IL-18 and ESR (R = 0.43, p = 0.0073), CRP (R = 0.47, p = 0.0025), and serum levels of IL-6 (R = 0.36, p = 0.023). An association was observed between serum levels of IL-6 and the presence of tophi (p = 0.005) and deformities (p = 0.0008), as well as a correlation between this cytokine and ESR (R = 0.41, p = 0.011) and CRP (R = 0.48, p = 0.02).

CONCLUSIONS

IL-18 is associated with inflammatory activity in gout, as well as with IL-6 levels, while IL-6 is associated with clinical and laboratory activity, the presence of tophi and articular deformities, and may be a prognostic marker of this pathology.

The role of danger signals and ectonucleotidases in acute graft-versus-host disease

Allogeneic hematopoietic cell transplantation (allo-HCT) represents the only curative treatment approach for many patients with benign or malignant diseases of the hematopoietic system. However, post-transplant morbidity and mortality are significantly increased by the development of acute graft-versus-host disease (GvHD). While alloreactive T cells act as the main cellular mediator of the GvH reaction, recent evidence suggests a critical role of the innate immune system in the early stages of GvHD initiation. Danger-associated molecular patterns released from the intracellular space as well as from the extracellular matrix activate antigen-presenting cells and set pro-inflammatory pathways in motion. This review gives an overview about danger signals representing therapeutic targets with a clinical perspective with a particular focus on extracellular nucleotides and ectonucleotidases.

Vinegar Treatment Prevents the Development of Murine Experimental Colitis via Inhibition of Inflammation and Apoptosis

This study investigated the preventive effects of vinegar and acetic acid (the active component of vinegar) on ulcerative colitis (UC) in mice. Vinegar (5% v/v) or acetic acid (0.3% w/v) treatment significantly reduced the disease activity index and histopathological scores, attenuated body weight loss, and shortened the colon length in a murine experimental colitis model induced by dextran sulfate sodium (DSS). Further mechanistic analysis showed that vinegar inhibited inflammation through suppressing Th1 and Th17 responses, the NLRP3 inflammasome, and MAPK signaling activation. Vinegar also inhibited endoplasmic reticulum (ER) stress-mediated apoptosis in the colitis mouse model. Surprisingly, pretreatment with vinegar for 28 days before DSS induction increased levels of the commensal lactic acid-producing or acetic acid-producing bacteria, including Lactobacillus, Bifidobacteria, and Enterococcus faecalis, whereas decreased Escherichia coli levels were found in the feces of mice. These results suggest that vinegar supplementation might provide a new dietary strategy for the prevention of UC.

Endogenous and Uric Acid-Induced Activation of NLRP3 Inflammasome in Pregnant Women with Preeclampsia

Preeclampsia (PE) is a specific syndrome of pregnancy, characterized by hypertension and proteinuria. This pathology is associated with hyperuricemia and elevated serum levels of inflammatory cytokines. Uric acid crystals may activate an intracellular complex called inflammasome, which is important for processing and release of inflammatory cytokines. This study investigated the state of monocyte activation, both endogenous and stimulated with monosodium urate (MSU), by gene expression of NLRP1 and NLRP3 receptors as well as their association with inflammatory cytokines expression. Monocytes were obtained from peripheral blood of 23 preeclamptic pregnant women, 23 normotensive pregnant women (NT) and 23 healthy non-pregnant women (NP). Inflammasome activation was evaluated by the gene expression of NLRP1, NLRP3, caspase-1, IL-1β, IL-18 and TNF-α by RT-qPCR in unstimulated monocytes (endogenous expression), or after cell stimulation with MSU (stimulated expression). The concentration of cytokines was assessed by ELISA. In preeclamptic pregnant women, gene expression of NLRP1, NLRP3, caspase-1, IL-1β and TNF-α by monocytes stimulated or not with MSU was significantly higher than in NT and NP groups. Stimulation of monocytes from preeclamptic and non-pregnant women with MSU induced increased gene expression of NLRP3, caspase-1 and TNF-α in relation to the endogenous expression in these groups, while this was not observed in the NT group. The cytokine determination showed that monocytes from women with PE produced higher endogenous levels of IL-1β, IL-18 and TNF-α compared to the other groups, while the stimulus with MSU led to higher production of these cytokines in preeclamptic group than in the NT group. In conclusion, the results showed increased basal gene expression of NLRP1 and NLRP3 receptors in monocytes from PE group. These cells stimulation with MSU demonstrates that uric acid plays a role in NLRP3 inflammasome activation, suggesting the participation of this inflammatory complex in the pathogenesis of preeclampsia.

Monosodium Urate Crystals Promote Innate Anti-Mycobacterial Immunity and Improve BCG Efficacy as a Vaccine against Tuberculosis

A safer and more effective anti-Tuberculosis vaccine is still an urgent need. We probed the effects of monosodium urate crystals (MSU) on innate immunity to improve the Bacille Calmette-Guerin (BCG) vaccination. Results showed that in vitro MSU cause an enduring macrophage stimulation of the anti-mycobacterial response, measured as intracellular killing, ROS production and phagolysosome maturation. The contribution of MSU to anti-mycobacterial activity was also shown in vivo. Mice vaccinated in the presence of MSU showed a lower number of BCG in lymph nodes draining the vaccine inoculation site, in comparison to mice vaccinated without MSU. Lastly, we showed that MSU improved the efficacy of BCG vaccination in mice infected with Mycobacterium tuberculosis (MTB), measured in terms of lung and spleen MTB burden. These results demonstrate that the use of MSU as adjuvant may represent a novel strategy to enhance the efficacy of BCG vaccination.

The sterile inflammation in the exacerbation of HBV-associated liver injury

Exacerbation of hepatitis B virus-associated liver injury is characterized by abnormal immune response which not only mobilizes specific antiviral effects but also poses a potentially lethal nonspecific sterile inflammation to the host. How nonspecific sterile inflammation is triggered after the preexisting injury caused by specific immune injury remains elusive. In the setting of sterile inflammation, endogenous damage-associated molecular patterns are released by stressed and dying hepatocytes, which alarm the immune system through their potential pattern recognition receptors and related signaling pathways, orchestrate the influx of diverse cytokines, and ultimately amplify liver destruction. This review highlights current knowledge about the sterile hepatic inflammation in the exacerbation of chronic hepatitis B.