Showing papers by "Charles A. Dinarello published in 2018"

Overview of the IL-1 family in innate inflammation and acquired immunity.

Abstract: The interleukin-1 (IL-1) family of cytokines and receptors is unique in immunology because the IL-1 family and Toll-like receptor (TLR) families share similar functions. More than any other cytokine family, the IL-1 family is primarily associated with innate immunity. More than 95% of living organisms use innate immune mechanisms for survival whereas less than 5% depend on T- and B-cell functions. Innate immunity is manifested by inflammation, which can function as a mechanism of host defense but when uncontrolled is detrimental to survival. Each member of the IL-1 receptor and TLR family contains the cytoplasmic Toll-IL-1-Receptor (TIR) domain. The 50 amino acid TIR domains are highly homologous with the Toll protein in Drosophila. The TIR domain is nearly the same and present in each TLR and each IL-1 receptor family. Whereas IL-1 family cytokine members trigger innate inflammation via IL-1 family of receptors, TLRs trigger inflammation via bacteria, microbial products, viruses, nucleic acids, and damage-associated molecular patterns (DAMPs). In fact, IL-1 family member IL-1a and IL-33 also function as DAMPs. Although the inflammatory properties of the IL-1 family dominate in innate immunity, IL-1 family member can play a role in acquired immunity. This overview is a condensed update of the IL-1 family of cytokines and receptors.

OLT1177, a β-sulfonyl nitrile compound, safe in humans, inhibits the NLRP3 inflammasome and reverses the metabolic cost of inflammation.

Abstract: Activation of the NLRP3 inflammasome induces maturation of IL-1β and IL-18, both validated targets for treating acute and chronic inflammatory diseases. Here, we demonstrate that OLT1177, an orally active β-sulfonyl nitrile molecule, inhibits activation of the NLRP3 inflammasome. In vitro, nanomolar concentrations of OLT1177 reduced IL-1β and IL-18 release following canonical and noncanonical NLRP3 inflammasome activation. The molecule showed no effect on the NLRC4 and AIM2 inflammasomes, suggesting specificity for NLRP3. In LPS-stimulated human blood-derived macrophages, OLT1177 decreased IL-1β levels by 60% and IL-18 by 70% at concentrations 100-fold lower in vitro than plasma concentrations safely reached in humans. OLT1177 also reduced IL-1β release and caspase-1 activity in freshly obtained human blood neutrophils. In monocytes isolated from patients with cryopyrin-associated periodic syndrome (CAPS), OLT1177 inhibited LPS-induced IL-1β release by 84% and 36%. Immunoprecipitation and FRET analysis demonstrated that OLT1177 prevented NLRP3-ASC, as well as NLRP3-caspase-1 interaction, thus inhibiting NLRP3 inflammasome oligomerization. In a cell-free assay, OLT1177 reduced ATPase activity of recombinant NLRP3, suggesting direct targeting of NLRP3. Mechanistically, OLT1177 did not affect potassium efflux, gene expression, or synthesis of the IL-1β precursor. Steady-state levels of phosphorylated NF-κB and IkB kinase were significantly lowered in spleen cells from OLT1177-treated mice. We observed reduced IL-1β content in tissue homogenates, limited oxidative stress, and increased muscle oxidative metabolism in OLT1177-treated mice challenged with LPS. Healthy humans receiving 1,000 mg of OLT1177 daily for 8 d exhibited neither adverse effects nor biochemical or hematological changes.

Suppression of inflammation and acquired immunity by IL-37

Abstract: IL-37 is a unique member of the IL-1 family of cytokines, which functions as a natural suppressor of inflammatory and immune responses. Immune and non-immune cells produce IL-37 precursor following pro-inflammatory stimuli. Following activating cleavage by caspase-1, mature IL-37 translocates to the nucleus, where it suppresses transcription of pro-inflammatory genes. Both precursor and mature IL-37 are also secreted in the extracellular space, where they bind IL-18Rα and recruit the IL-1R8 (formerly TIR8 or SIGIRR), which transduces anti-inflammatory signals by suppressing NF-kB and MAPK and by activating Mer-PTEN-DOK pathways. During inflammation, IL-37 restores the metabolism of the cell by reducing succinate, inhibiting mTOR, and activating AMPK. Transgenic mice expressing human IL-37 and wild type mice treated with recombinant human IL-37 are protected from several experimental models of inflammation, including endotoxin shock, colitis, lung and spinal cord injury, coronary artery disease, arthritis and inflammation-induced fatigue, while also exhibiting reduced adaptive immune responses. In humans, IL-37 likely functions to limit excessive inflammation: accordingly, IL-37 levels are abnormal in patients with inflammatory and autoimmune diseases. In this review, we provide an overview of the discovery and biology of IL-37, and discuss the potential for development of this cytokine as a therapeutic agent.

Anakinra Therapy for Non-cancer Inflammatory Diseases.

Abstract: Interleukin-1 (IL-1) is the prototypical inflammatory cytokine: two distinct ligands (IL-1α and IL-1β) bind the IL-1 type 1 receptor (IL-1R1) and induce a myriad of secondary inflammatory mediators, including prostaglandins, cytokines, and chemokines. IL-1α is constitutively present in endothelial and epithelial cells, whereas IL-1β is inducible in myeloid cells and released following cleavage by caspase-1. Over the past 30 years, IL-1-mediated inflammation has been established in a broad spectrum of diseases, ranging from rare autoinflammatory diseases to common conditions such as gout and rheumatoid arthritis (RA), type 2 diabetes, atherosclerosis, and acute myocardial infarction. Blocking IL-1 entered the clinical arena with anakinra, the recombinant form of the naturally occurring IL-1 receptor antagonist (IL-1Ra); IL-1Ra prevents the binding of IL-1α as well as IL-1β to IL-1R1. Quenching IL-1-mediated inflammation prevents the detrimental consequences of tissue damage and organ dysfunction. Although anakinra is presently approved for the treatment of RA and cryopyrin-associated periodic syndromes, off-label use of anakinra far exceeds its approved indications. Dosing of 100 mg of anakinra subcutaneously provides clinically evident benefits within days and for some diseases, anakinra has been used daily for over 12 years. Compared to other biologics, anakinra has an unparalleled record of safety: opportunistic infections, particularly Mycobacterium tuberculosis, are rare even in populations at risk for reactivation of latent infections. Because of this excellent safety profile and relative short duration of action, anakinra can also be used as a diagnostic tool for undefined diseases mediated by IL-1. Although anakinra is presently in clinical trials to treat cancer, this review focuses on anakinra treatment of acute as well as chronic inflammatory diseases.

Histone deacetylase activity governs diastolic dysfunction through a nongenomic mechanism

Abstract: There are no approved drugs for the treatment of heart failure with preserved ejection fraction (HFpEF), which is characterized by left ventricular (LV) diastolic dysfunction. We demonstrate that ITF2357 (givinostat), a clinical-stage inhibitor of histone deacetylase (HDAC) catalytic activity, is efficacious in two distinct murine models of diastolic dysfunction with preserved EF. ITF2357 blocked LV diastolic dysfunction due to hypertension in Dahl salt-sensitive (DSS) rats and suppressed aging-induced diastolic dysfunction in normotensive mice. HDAC inhibitor-mediated efficacy was not due to lowering blood pressure or inhibiting cellular and molecular events commonly associated with diastolic dysfunction, including cardiac fibrosis, cardiac hypertrophy, or changes in cardiac titin and myosin isoform expression. Instead, ex vivo studies revealed impairment of cardiac myofibril relaxation as a previously unrecognized, myocyte-autonomous mechanism for diastolic dysfunction, which can be ameliorated by HDAC inhibition. Translating these findings to humans, cardiac myofibrils from patients with diastolic dysfunction and preserved EF also exhibited compromised relaxation. These data suggest that agents such as HDAC inhibitors, which potentiate cardiac myofibril relaxation, hold promise for the treatment of HFpEF in humans.

IL-38 has an anti-inflammatory action in psoriasis and its expression correlates with disease severity and therapeutic response to anti-IL-17A treatment.

Abstract: IL-36 cytokines, a subgroup of IL-1 family, comprise IL-36α, IL-36β, and IL-36γ agonists, abundantly expressed in psoriatic skin, and IL-36RA and IL-38 antagonists. In psoriatic skin, IL-36 cytokines interfere with keratinocyte cornification programs and induce the release of antimicrobial peptides and chemokines active on neutrophils and Th17 lymphocytes. To date, the role of IL-38 antagonist in psoriasis remains to be defined. Here, we demonstrate that skin and circulating IL-38 levels are reduced in psoriatic patients and in other skin diseases characterized by neutrophilic infiltrate. In psoriasis, the balance of IL-36γ agonist/IL-38 antagonist serum levels is in favor of agonists and is closely associated with disease severity. Interestingly, IL-38 is upregulated by anti-IL-17A biological treatment and positively correlates with the therapeutic efficacy of secukinumab in psoriatic patients. The downregulation of IL-38 expression is strictly related to keratinocyte de-differentiation triggered by the inflammatory cytokines IL-36γ, IL-17, and IL-22. Finally, we demonstrate that administration of recombinant full-length IL-38 counteracts in vitro the biological processes induced by IL-36γ in human keratinocytes and endothelial cells and attenuates in vivo the severity of the psoriasiform phenotype induced by IMQ in mice. Such effects are achieved by restoring the physiological programs of keratinocyte proliferation and differentiation, and reducing the immune cell infiltrates.

NLRP3 inflammasome inhibitor OLT1177 suppresses joint inflammation in murine models of acute arthritis.

Abstract: Activation of the NLRP3 inflammasome in gout amplifies the inflammatory response and mediates further damage. In the current study, we assessed the therapeutic effect of OLT1177, an orally active NLRP3 inflammasome inhibitor that is safe in humans, in murine acute arthritis models. Zymosan or monosodium urate (MSU) crystals were injected intra-articularly (i.a.) into mouse knee joints to induce reactive or gouty arthritis. Joint swelling, articular cell infiltration, and synovial cytokines were evaluated 25 hours and 4 hours following zymosan or MSU challenge, respectively. OLT1177 was administrated intraperitoneally by oral gavage or in the food by an OLT1177-enriched diet. OLT1177 reduced zymosan-induced joint swelling (p 0.0001), which was associated with decreased synovial IL-1β, IL-6, myeloperoxidase, and CXCL1 levels (p < 0.01) compared with vehicle-treated mice. When administrated orally 1 hour after MSU challenge, OLT1177 reduced joint inflammation, processing of IL-1β, and synovial phosphorylated c-Jun N-terminal kinase compared with the vehicle group. Mice were fed an OLT1177-enriched diet for 3 weeks and then challenged i.a. with MSU crystals. Joint swelling, synovial IL-1β, and expression of Nlrp3 and Il1b were significantly reduced in synovial tissues in mice fed an OLT1177-enriched diet when compared with the standard diet group. Oral OLT1177 is highly effective in ameliorating reactive as well as gouty arthritis.

Biology of IL‐38 and its role in disease

Abstract: IL-38 belongs to the IL-36 cytokines, which in turn are part of the IL-1 family. The first biological function of IL-38 described was blocking the activation of the IL-36R signaling similar to IL-36Ra. Since IL-36 cytokines require processing in order to become fully active, it is likely that IL-38 also must be processed to become maximally active. However, the protease(s) responsible for this is currently not known. In addition of IL-38 binding IL-36R, it has been proposed it can also interact with the co-receptor TIGIRR2. IL-38 is expressed in several tissues including tonsils, placenta, heart and brain, and IL-38 has been implicated in a wide variety of diseases including cardiovascular and autoimmune disease. Here, we discuss the discovery and biological function of IL-38, and its role in the pathogenesis of a wide variety of diseases.

The Inter-Relationship of Platelets with Interleukin-1β-Mediated Inflammation in Humans

Abstract: Background Inflammation and coagulation are key processes in cardiovascular diseases (CVDs). The Canakinumab Anti-inflammatory Thrombosis Outcome Study trial affirmed the importance of inflammation in CVD by showing that inhibition of the interleukin (IL)-1β pathway prevents recurrent CVD. A bi-directional relationship exists between inflammation and coagulation, but the precise interaction of platelets and IL-1β-mediated inflammation is incompletely understood. We aimed to determine the inter-relationship between platelets and inflammation-and especially IL-1β-in a cohort of healthy volunteers. Methods We used data from the 500-Human Functional Genomics cohort, which consists of approximately 500 Caucasian, healthy individuals. We determined associations of plasma levels of IL-1β and other inflammatory proteins with platelet number and reactivity, the association of platelet reactivity with ex vivo cytokine production as well as the impact of genetic variations through a genome-wide association study (GWAS). Results Platelets were associated with IL-1β on different levels. First, platelet number was positively associated with plasma IL-1β concentrations (p = 8.9 × 10-9) and inversely with concentrations of α-1-anti-trypsin (p = 1.04 × 10-18), which is a known antagonist of IL-1β. Second, platelet degranulation capacity, as determined by agonist-induced P-selectin expression, was associated with ex vivo IL-1β and IL-6 production. Third, several platelet single-nucleotide polymorphisms (SNPs) were associated with cytokine production and there was a significant platelet SNP enrichment in specific biological important pathways. Finally, platelet SNPs were enriched among SNPs earlier identified in GWAS studies in blood-related diseases and immune-mediated diseases. Conclusion This comprehensive assessment of factors associated with platelet number and reactivity reinforces the important inter-relationship of platelets and IL-1β-mediated inflammation.

Role of glutathione metabolism in host defense against Borrelia burgdorferi infection.

Abstract: Pathogen-induced changes in host cell metabolism are known to be important for the immune response. In this study, we investigated how infection with the Lyme disease-causing bacterium Borrelia burgdorferi (Bb) affects host metabolic pathways and how these metabolic pathways may impact host defense. First, metabolome analysis was performed on human primary monocytes from healthy volunteers, stimulated for 24 h with Bb at low multiplicity of infection (MOI). Pathway analysis indicated that glutathione (GSH) metabolism was the pathway most significantly affected by Bb Specifically, intracellular levels of GSH increased on average 10-fold in response to Bb exposure. Furthermore, these changes were found to be specific, as they were not seen during stimulation with other pathogens. Next, metabolome analysis was performed on serum samples from patients with early-onset Lyme disease in comparison with patients with other infections. Supporting the in vitro analysis, we identified a cluster of GSH-related metabolites, the γ-glutamyl amino acids, specifically altered in patients with Lyme disease, and not in other infections. Lastly, we performed in vitro experiments to validate the role for GSH metabolism in host response against Bb. We found that the GSH pathway is essential for Bb-induced cytokine production and identified glutathionylation as a potential mediating mechanism. Taken together, these data indicate a central role for the GSH pathway in the host response to Bb GSH metabolism and glutathionylation may therefore be important factors in the pathogenesis of Lyme disease and potentially other inflammatory diseases as well.

Treatment of Dilated Cardiomyopathy With Interleukin-1 Inhibition.

Abstract: Treatment of Dilated Cardiomyopathy With Interleukin-1 Inhibition Background: Dilated cardiomyopathy is a severe, irreversible form of heart disease characterized by left ventricular systolic dysfunction and dilation that are not explained by abnormal loading or coronary artery disease. The current mainstay of treatment is symptomatic management of heart failure and arrhythmia. Novel, effective therapeutic options are an unmet clinical need (1). The central role of inflammation in heart failure is now established, and the heart exhibits a stereotyped inflammatory response to injury that is mediated by interleukin-1. Selective inhibition of this cytokine has thus emerged as an intriguing therapeutic opportunity (2). Objective: To report the results of treatment focused on dampening the inflammation mediated by interleukin-1 in a patient with dilated cardiomyopathy. Methods and Findings: A 57-year-old man with a 2-year history of dilated cardiomyopathy was hospitalized for chronic fatigue and dyspnea secondary to New York Heart Association class III heart failure. Transthoracic echocardiography revealed a severely dilated, hypokinetic left ventricle (left ventricular ejection fraction [LVEF], 28%), and cardiac catheterization showed normal coronary arteries. We optimized his treatment with diuretics, -blockers, and angiotensin-converting enzyme inhibitors and discharged him to outpatient care. Six months later (baseline in the Table), he remained symptomatic. Results of blood tests were unremarkable except for elevated troponin T and N-terminal pro–B-type natriuretic peptide levels. Holter electrocardiography revealed many ventricular ectopic beats per 24 hours. Repeated transthoracic echocardiography showed a severely dilated, hypokinetic left ventricle confirmed with magnetic resonance imaging. Magnetic resonance imaging with short -inversion recovery to suppress the signal from fat also revealed that the lateral wall had subepicardial myocardial edema with subendocardial late gadolinium enhancement. Results of endomyocardial biopsy revealed myocardiocyte enlargement, focal fibrosis, and a predominantly lymphocytic inflammatory infiltrate; immunohistochemistry studies showed a CD3 cell count > 7 mm (Figure). A comprehensive search found no autoantibodies in the blood or viral genome sequences in the biopsy specimen. We determined that the patient met criteria for idiopathic inflammatory dilated cardiomyopathy. Given his continuing symptoms despite optimal therapy, we began treatment with anakinra, the recombinant form of the endogenous antagonist for the interleukin-1 receptor, administered at a standard subcutaneous dose of 100 mg/d (3). The clinical response was striking. Within 2 weeks (Table), the patient's clinical symptoms related to heart failure markedly improved to New York Heart Association class I. Transthoracic echocardiography revealed an increase in the LVEF, and 24-hour Holter electrocardiography showed fewer ventricular ectopic beats. Troponin T and N-terminal pro–B-type natriuretic peptide levels normalized. Four weeks after starting anakinra therapy, transthoracic echocardiography revealed a further increase in the LVEF confirmed on magnetic resonance imaging. Late gadolinium enhancement was unchanged, but short -inversion recovery sequences showed that the myocardial edema had nearly resolved. The ventricular ectopic beats nearly disappeared. A decrease in the serum interleukin-6 level, which measures the amount of inflammation sustained by interleukin-1, confirmed that anakinra had effectively suppressed the inflammation. Discussion: This patient with dilated cardiomyopathy experienced what we believe to be unprecedented clinical improvement with use of anakinra to inhibit interleukin-1. Improvement began soon after anakinra administration and was obvious by every measure. The patient felt better and was able to lead a more normal life. The arrhythmia improved;

An Interleukin-1 Signature in Breast Cancer Treated with Interleukin-1 Receptor Blockade: Implications for Treating Cytokine Release Syndrome of Checkpoint Inhibitors.

Abstract: In this issue of Cancer Research, Wu and colleagues show that IL1b orchestrates tumor-promoting inflammation in breast cancer and can be targeted in patients using an IL1 receptor antagonist Cancer Res; 78(18); 5200-2 ©2018 AACRSee related article by Wu et al, p 5243

Treatment of HIV-Infected Individuals with the Histone Deacetylase Inhibitor Panobinostat Results in Increased Numbers of Regulatory T Cells and Limits Ex Vivo Lipopolysaccharide-Induced Inflammatory Responses.

Abstract: Histone deacetylase inhibitors (HDACi) modulate the transcriptional activity of all cells, including innate and adaptive immune cells. Therefore, we aimed to evaluate immunological effects of treatment with the HDACi panobinostat in HIV-infected patients during a clinical phase IIa latency reversal trial. Using flow cytometry, we investigated changes in T cell activation (CD69, CD38, HLA-DR) and the expression of CD39 and CTLA4 on regulatory T cells (Tregs). Whole-blood stimulations were performed and cytokine responses measured using Luminex. Gene expression in purified peripheral blood mononuclear cells (PBMCs) was evaluated using an Affymetrix HTA 2.0 gene chip. We found that proportions of CD4+ and CD8+ T cells expressing CD69 increased 24 h after initial panobinostat administration (P 1.5; false-discovery-rate [FDR]-corrected P, IMPORTANCE The effect of treatment with histone deacetylase inhibitors on the immune system in HIV-infected individuals is not clear. Analysis of results from a clinical trial in which 15 HIV-infected individuals received 12 doses of panobinostat identified a significant impact on both T cell activation status and regulatory T cell suppressive marker expression and a reduced level of monocytic responsiveness to inflammatory stimuli. These changes were substantiated by global gene expression analysis. Collectively, the results suggest that panobinostat has multiple effects on innate and adaptive immune responses. Importantly, all the effects were transient, and further panobinostat treatment did not cause persistent long-term changes in gene expression patterns in HIV-infected individuals.

TLR9 and IL-1R1 Promote Mobilization of Pulmonary Dendritic Cells during Beryllium Sensitization

Abstract: Metal-induced hypersensitivity is driven by dendritic cells (DCs) that migrate from the site of exposure to the lymph nodes, upregulate costimulatory molecules, and initiate metal-specific CD4+ T cell responses Chronic beryllium disease (CBD), a life-threatening metal-induced hypersensitivity, is driven by beryllium-specific CD4+ Th1 cells that expand in the lung-draining lymph nodes (LDLNs) after beryllium exposure (sensitization phase) and are recruited back to the lung, where they orchestrate granulomatous lung disease (elicitation phase) To understand more about how beryllium exposures impact DC function during sensitization, we examined the early events in the lung and LDLNs after pulmonary exposure to different physiochemical forms of beryllium Exposure to soluble or crystalline forms of beryllium induced alveolar macrophage death/release of IL-1α and DNA, enhanced migration of CD80hi DCs to the LDLNs, and sensitized HLA-DP2 transgenic mice after single low-dose exposures, whereas exposures to insoluble particulate forms beryllium did not IL-1α and DNA released by alveolar macrophages upregulated CD80 on immature BMDC via IL-1R1 and TLR9, respectively Intrapulmonary exposure of mice to IL-1R and TLR9 agonists without beryllium was sufficient to drive accumulation of CD80hi DCs in the LDLNs, whereas blocking both pathways prevented accumulation of CD80hi DCs in the LDLNs of beryllium-exposed mice Thus, in contrast to particulate forms of beryllium, which are poor sensitizers, soluble or crystalline forms of beryllium promote death of alveolar macrophages and their release of IL-1α and DNA, which act as damage-associated molecular pattern molecules to enhance DC function during beryllium sensitization

Ethanol-mediated suppression of IL-37 licenses alcoholic liver disease.

Abstract: Background & aims Chronic alcohol consumption and alcoholic liver disease (ALD) afflicts individuals with substantial morbidity and mortality with limited treatment options available. Hepatic inflammation, triggered by activated Kupffer cells, is a driving force in alcoholic liver disease. Interleukin 37 (IL-37) exerts anti-inflammatory effects in hepatic diseases, however, the impact of Interleukin 37 on alcoholic liver disease is unknown. In this study, we addressed the role of Interleukin 37 in alcoholic liver disease. Methods We utilized Interleukin 37 expressing transgenic mice and human recombinant Interleukin 37 in models of alcoholic liver disease. Interleukin 37 expression was measured in liver samples of 20 alcoholic steatohepatitis and 36 non-alcoholic fatty liver disease patients. Results Interleukin 37 transgenic mice are not protected against hepatic injury and inflammation in alcoholic liver disease. Ethanol suppressed Interleukin 37 expression in transgenic mice. Alcoholic steatohepatitis (ASH) patients similarly exhibited reduced Interleukin 37 expression when compared to non-alcoholic fatty liver disease (NAFLD) patients. Human recombinant Interleukin 37 ameliorated hepatic inflammation in a binge drinking model of alcoholic liver disease. Conclusion We provide evidence for an exogenous noxae that suppresses Interleukin 37 expression which limits its anti-inflammatory effects in alcoholic liver disease.

Human Interleukin-32γ Plays a Protective Role in an Experimental Model of Visceral Leishmaniasis in Mice.

Abstract: Visceral leishmaniasis (VL) is a chronic parasitic disease caused by Leishmania infantum in the Americas. During VL, several proinflammatory cytokines are produced in spleen, liver, and bone marrow. However, the role of interleukin-32 (IL-32) has not been explored in this disease. IL-32 can induce production of proinflammatory cytokines in innate immune cells and polarize the adaptive immune response. Herein, we discovered that L. infantum antigens induced expression of mRNA mainly for the IL-32γ isoform but also induced low levels of the IL-32β transcript in human peripheral blood mononuclear cells. Furthermore, infection of human IL-32γ transgenic mice (IL-32γTg mice) with L. infantum promastigote forms increased IL-32γ expression in the spleen and liver. Interestingly, IL-32γTg mice harbored less parasitism in the spleen and liver than wild-type (WT) mice. In addition, IL-32γTg mice showed increased granuloma formation in the liver compared to WT mice. The protection against VL was associated with increased production of nitric oxide (NO), interferon gamma (IFN-γ), IL-17A, and tumor necrosis factor alpha by splenic cells restimulated ex vivo with L. infantum antigens. In parallel, there was an increase in the number of Th1 and Th17 T cells in the spleens of IL-32γTg mice infected with L. infantum IL-32γ induction of IFN-γ and IL-17A expression was found to be essential for NO production by splenic cells of infected animals. These data indicate that IL-32γ potentiates the Th1/Th17 immune response during experimental VL, thus contributing to the control of L. infantum infection.

Indeed, IL-18 is more than an inducer of IFN-γ.

Abstract: Most immune related studies on IL-18 have focused on its property to induce IFN-γ . Indeed, Haruki Okamura and coworkers described in 1995 the release of a cytokine from Propionibacterium acnes-primed liver macrophages stimulated with LPS and gave the cytokine the name “IFN-γ inducing factor”.1 In this issue of the Journal, El-Darawish reports that recombinant IL-18 primes resting mouse spleen-derived NKcells to transduce effective signals, which allows IL-2 to trigger proliferation and survival of NK cells.2 Themain point of their study is that IL-18 is the driver of signal transduction via PI3/AKT, mTOR, ATG, and LC3 in NK cells. IL-18 primed NK cells respond to IL-2 and increase CD25 expression. Using IL-18 deficientmouseNK cells, there is no significant expansion. There is considerable clinical importance to IL-18 in the context of NK cells survival. As described below in this commentary, IL-18 activation of NK cells is consistent with the pathogenesis of the hemophagocytic lymphohistiocytosis syndrome and the related macrophageactivation syndrome.However, in their SignificanceStatement, the authors state “The concept that IL-18 is merely an IFN-γinducer limited research of IL-18 roles in other cellular processes”. We disagreewith this view that research on IL-18was limited to the induction of IFN-γ . On the contrary, research on IL-18 has been studied extensively during the last 20 years in models of human disease and cellular activation quite independent of IFN-γ . The early studies of IL-18 focused on its similarities with IL-1β because the precursor forms of both cytokines require caspase-1 cleavage to convert to active cytokines. However, IL-18 is hardly a recapitulation of IL-1β . The precursor of IL-18 is present constitutively in epithelial cells of the skin, liver, gastrointestinal tract, and kidney of healthy humans and healthy mice, whereas IL-1β is not constitutive in health and is not found in epithelial cells.3 Recent interest in IL-18 comes from missense mutations in NLRP3 where loss of control of caspase-1 cleavage results in a large spectrum of inflammatory diseases termed “autoinflammatory”. In general, manifestations of autoinflammatory diseases are independent of T-cells and IFN-γ . Mice deficient in IL-18 spontaneously develop metabolic syndrome while eating a standard mouse diet. This study and several others reveal the anti-inflammatory properties of IL-18 as reviewed in Ref. 3. IL-18 also plays a significant a role in myocardial suppression, heart failure, and atherosclerosis.3 In heart failure, it is difficult to envision a role for IFN-γ .4 Figure1 lists properties of IL-18,which are independent aswell as related to IFN-γ .3

The selective ROCK2 inhibitor KD025 reduces IL-17 secretion in human peripheral blood mononuclear cells independent of IL-1 and IL-6

Abstract: Reducing the activities of the pro-inflammatory cytokine IL-17 is an effective treatment strategy for several chronic autoimmune disorders. Rho-associated coiled-coil containing kinase 2 (ROCK2) is a member of the serine-threonine protein kinase family that regulates IL-17 secretion in T cells via signal transducer and activator of transcription 3 (STAT3)-dependent mechanism. We reported here that the selective ROCK2 inhibitor KD025 significantly reduced in vitro production of IL-17 in unfractionated human peripheral blood mononuclear cells (PBMCs) stimulated with the dectin-1 agonist Candida albicans. C. albicans induced IL-17 was reduced by 70% (p < 0.0001); a similar reduction (80%) was observed in PBMC stimulated with the Toll-like receptor 2 agonist Staphylococcus epidermidis (p < 0.0001). Treatment of PBMC with KD025 was not associated with a reduction in IL-1beta, IL-6 or IL-1alpha levels; in contrast, a 1.5 fold increase in the level of IL-1 receptor antagonist (IL-1Ra) was observed (p < 0.001). KD025 down-regulated C. albicans-induced Myosin Light Chain and STAT3, whereas STAT5 phosphorylation increased. Using anti-CD3/CD28 activation of the TCR, KD025 similarly suppressed IL-17 independent of a reduction in IL-1beta. Thus, ROCK2 directly regulates IL-17 secretion independent of endogenous IL-1 and IL-6 supporting development of selective ROCK2 inhibitors for treatment of IL-17-driven inflammatory diseases.

Treatment of Inflammatory Diseases with IL-1 Blockade

Abstract: To provide evidence that therapeutic blockade of IL-1 can provide benefit for patients with hearing loss. In this review, we assess clinical trials of the IL-1 receptor antagonist (anakinra), the soluble IL-1 receptor (rilonacept), antibodies to interleukin-1 beta (IL-1β) (canakinumab, gevokizumab), and anti-IL-1α (xilonix) for clinical indications not related to hearing loss but rather to disease conditions that are common to inflammatory diseases. One purpose of this review is to distinguish between autoinflammatory diseases and autoimmune diseases. Whereas autoinflammatory diseases are due to dysfunctional T cells and B cells, autoinflammatory diseases are due to overproduction of macrophage cytokines particularly IL-1β. A causative role for IL-1 in autoinflammatory diseases is derived from clinical studies blocking the IL-1 receptor or neutralizing monoclonal antibodies or soluble receptors. Off-label use of anakinra is common for a broad spectrum of inflammatory diseases. Neutralization of IL-1β is used to treat not only hereditary autoinflammatory diseases but also atherosclerosis. Rilonacept reduces arterial wall inflammation in patients with chronic kidney disease. Neutralization of IL-1α has prolonged life in patients with advanced metastatic colorectal cancer. Compared to other cytokine blocking therapies, reducing the activities of IL-1 has an excellent safety record. Blocking IL-1 therapies can be used to treat a wide spectrum of acute and chronic inflammatory diseases.

OP0170 Human il-38 reduces joint inflammation in a mouse model of gouty arthritis

Abstract: Background Interleukin-38 (IL-38) is the last member of the IL-1 family of cytokines to be fully investigated for its functions. IL-38 is proposed as an anti-inflammatory cytokine in various auto-inflammatory diseases, such as psoriasis and rheumatoid arthritis. For example, IL-38 knockout mice have exacerbated autoantibody-induced arthritis. Current understanding of the capacity of IL-38 in gout, a prototype IL-1β driven auto-inflammatory disease, is unknown. Objectives We hypothesised that in vivo treatment with human recombinant IL-38 results in a reduction in join inflammation in a mouse model of gouty arthritis. Methods We treated C57/Bl6 mice with 1 µg recombinant IL-38 (3–152 AA) intraperitoneally at 24, 12 and 2 hours before induction of gouty arthritis with intra-articular injection of albumin-opsonized monosodium urate crystals (300 µg) and palmitic acid (200 µM) in 10 µL PBS. Joint inflammation was scored after 4 hours. The synovial lining was cultured in RPMI for 2 hours to allow cytokines to be secreted, and cytokines in the synovium were extracted with Triton-X 100 to obtain total cytokines (membrane and intracellular). In the synovial culture fluid and extract, IL-1β, IL-6 and KC were measured by ELISA. Data Results Mice treated with recombinant IL-38 exhibited significantly reduced joint swelling and redness on a three-point macroscopic inflammation scale: Vehicle-treated 1.5±0.25 vs IL-38 Treated 0.75+0.25 (n=10, p Conclusions Human recombinant IL-38 reduces swelling and redness of the joint, and pro-inflammatory cytokines secreted by and contained in the synovial membrane in a mouse model of gouty arthritis. These data reveal that recombinant IL-38 has therapeutic benefit in an IL–1β mediated model of inflammation. Disclosure of Interest None declared

IL-37 Expression Reduces Lean Body Mass in Mice by Reducing Food Intake

Abstract: The human cytokine interleukin (IL)-37 is an anti-inflammatory member of the IL-1 family of cytokines. Transgenic expression of IL-37 in mice protects them from diet-induced obesity and associated metabolic complications including dyslipidemia, inflammation and insulin resistance. The precise mechanism of action leading to these beneficial metabolic effects is not entirely known. Therefore, we aimed to assess in detail the effect of transgenic IL-37 expression on energy balance, including food intake and energy expenditure. Feeding homozygous IL-37 transgenic mice and wild-type (WT) control mice a high-fat diet (HFD; 45% kcal palm fat) for 6 weeks showed that IL-37 reduced body weight related to a marked decrease in food intake. Subsequent mechanistic studies in mice with heterozygous IL-37 expression versus WT littermates, fed the HFD for 18 weeks, confirmed that IL-37 reduces food intake, which led to a decrease in lean body mass, but did not reduce fat mass and plasma lipid levels or alterations in energy expenditure independent of lean body mass. Taken together, this suggests that IL-37 reduces lean body mass by reducing food intake.

OP0285 Identification of rare coding variants in il-1-related pathways in patients with adult-onset still’s disease

Abstract: Background Adult-onset Still’s disease (AOSD) is a rare autoinflammatory disease characterised by fever, arthritis, and multi-organ involvement. Inflammation in AOSD is mediated by interleukin (IL)−1β, as confirmed by the dramatic clinical efficacy of selective blockers of this cytokine. The genetic predisposition to this rampant IL-1-driven inflammation remains nevertheless elusive. Previous studies failed to identify associations between polymorphisms in the genes encoding IL-1 and AOSD, thus pointing at more complex genetic mechanisms. This ‘missing heritability’ cannot be adequately investigated with traditional techniques for genetic partitioning, such as GWAS, which only assess common variants and polymorphisms. Studies focusing on highly penetrant rare variants or different types of mutations (i.e. small copy-number variations; insertions/deletions) are warranted. Objectives We hypothesised that genetically determined changes in IL-1-related pathways resulting in excessive IL-1β activity lead to the development of autoinflammation in AOSD. Scope of this study was to unravel the combined mutational variation of a network of IL-1-related receptors, pathways, counter-regulators, and cellular processes possibly involved in the pathogenesis of AOSD and IL-1-mediated inflammation in general. Methods We collected clinical, demographic, and genetic data from a large cohort of 76 AOSD patients and developed an innovative platform based on molecular inversion probes (MIP) technology for performing highly multiplexed targeted-resequencing. This allows efficient sequencing of the coding sequence of 48 genes related to the IL-1-pathway, and allows studying rare and common variants in one assay. We have also screened 500 healthy controls, and 1000s of samples with other disorders using the same assay. Results We identified rare and unique (i.e. private variants) in the IL1 pathway in several individuals with AOSD. Whether any these are involved in a strong predisposition to AOSD is currently followed-up. Rare genetic variants have been identified in six IL-1-pathway ‘clusters’: Deregulated activation of the inflammasome and release of IL–1β and IL–18. IL–1 family receptors and intracellular signalling mediators. Other pro–inflammatory cytokines and receptors. Regulatory molecules, including IL–1Ra or IL–37. Cellular processes regulating production of IL–1 and IL–18 (i.e. autophagy). Production of ROS, which function as markers of cellular damage and trigger inflammation. Conclusions Unravelling the genetic bases of inflammation in AOSD deepens our understanding of the human innate immunome. Of note, this study platform may serve for the genetic analysis of other IL-1-mediated conditions, including gout and other autoinflammatory diseases, whose genetic predisposition remains elusive. Equally important, the identification of pathways amenable to targeting with small molecules or biologics may translate into remarkable clinical implications. Disclosure of Interest None declared