Production Of IL-1 Receptor Antagonist Research Articles

An anti-inflammatory property of Candida albicans β-glucan: Induction of high levels of interleukin-1 receptor antagonist via a Dectin-1/CR3 independent mechanism

BackgroundCandida albicans is an opportunistic fungal pathogen that induces strong proinflammatory responses, such as IL-1β production. Much less is known about the induction of immune modulatory cytokines, such as the IL-1 receptor antagonist (IL-1Ra) that is the main natural antagonist of IL-1, by C. albicans. MethodsPeripheral blood mononuclear cells (PBMC) of healthy individuals were stimulated with C. albicans and different components of the fungal cell wall. The role of pathogen recognition receptors (PRRs) for the induction of IL-1β and IL-1Ra was investigated by using specific blockers or in PBMC from Dectin-1 deficient patients. ResultsC. albicans induced a strong IL-1Ra response, and this induction was primarily induced by the cell-wall component β-glucan. Blocking IL-1Ra significantly increased C. albicans β-glucan hyphae induced IL-1β and IL-6 production. Surprisingly, blocking the β-glucan receptor Dectin-1 or the downstream Syk or Raf-1 pathways only marginally reduced C. albicans-induced IL-1Ra production, while blocking of the complement receptor 3 (CR3), TLR2 or TLR4 had no effect. In line with this, blocking MAP kinases had little effect on Candida-induced IL-1Ra production. PBMC isolated from Dectin-1 deficient patients produced normal IL-1Ra amounts in response to C. albicans stimulation. Interestingly, the IL-1Ra synthesis induced by β-glucan was blocked by inhibitors of the Akt/PI3K pathway. Conclusionsβ-glucan of C. albicans induces a strong IL-1Ra response, which is independent of the β-glucan receptors dectin-1 and CR3. These data strongly argue for the existence of an unknown β-glucan receptor that specifically induces an Akt/PI3K-dependent anti-inflammatory IL-1Ra response upon recognition of C. albicans.

IL-10–overexpressing B cells regulate innate and adaptive immune responses

Distinct human IL-10-producing B-cell subsets with immunoregulatory properties have been described. However, the broader spectrum of their direct cellular targets and suppressive mechanisms has not been extensively studied, particularly in relation to direct and indirect IL-10-mediated functions. The aim of the study was to investigate the effects of IL-10 overexpression on the phenotype and immunoregulatory capacity of B cells. Primary human B cells were transfected with hIL-10, and IL-10-overexpressing B cells were characterized for cytokine and immunoglobulin production by means of specific ELISA and bead-based assays. Antigen presentation, costimulation capacity, and transcription factor signatures were analyzed by means of flow cytometry and quantitative RT-PCR. Effects of IL-10-overexpresing B cells on Toll-like receptor-triggered cytokine release from PBMCs, LPS-triggered maturation of monocyte-derived dendritic cells, and tetanus toxoid-induced PBMC proliferation were assessed in autologous cocultures. IL-10-overexpressing B cells acquired a prominent immunoregulatory profile comprising upregulation of suppressor of cytokine signaling 3 (SOCS3), glycoprotein A repetitions predominant (GARP), the IL-2 receptor α chain (CD25), and programmed cell death 1 ligand 1 (PD-L1). Concurrently, their secretion profile was characterized by a significant reduction in levels of proinflammatory cytokines (TNF-α, IL-8, and macrophage inflammatory protein 1α) and augmented production of anti-inflammatory IL-1 receptor antagonist and vascular endothelial growth factor. Furthermore, IL-10 overexpression was associated with a decrease in costimulatory potential. IL-10-overexpressing B cells secreted less IgE and potently suppressed proinflammatory cytokines in PBMCs, maturation of monocyte-derived dendritic cells (rendering their profile to regulatory phenotype), and antigen-specific proliferation in vitro. Our data demonstrate an essential role for IL-10 in inducing an immunoregulatory phenotype in B cells that exerts substantial anti-inflammatory and immunosuppressive functions.

α1-antitrypsin increases interleukin-1 receptor antagonist production during pancreatic islet graft transplantation.

Although islet transplantation for individuals with type 1 diabetes has been shown to yield superior blood glucose control, it remains inadequate for long-term control. This is partly due to islet injuries and stresses that can lead to beta cell loss. Inhibition of excess IL-1β activity might minimize islet injuries, thus preserving function. The IL-1 receptor antagonist (IL-1Ra), an endogenous inhibitor of IL-1β, protects islets from cytokine-induced necrosis and apoptosis. Therefore, an imbalance between IL-1β and IL-1Ra might influence the courses of allogeneic and autoimmune responses to islets. Our group previously demonstrated that the circulating serine-protease inhibitor human alpha-1-antitrypsin (hAAT), the levels of which increase in circulation during acute-phase immune responses, exhibits anti-inflammatory and islet-protective properties, as well as immunomodulatory activity. In the present study, we sought to determine whether the pancreatic islet allograft-protective activity of hAAT was mediated by IL-1Ra induction. Our results demonstrated that hAAT led to a 2.04-fold increase in IL-1Ra expression in stimulated macrophages and that hAAT-pre-treated islet grafts exhibited a 4.851-fold increase in IL-1Ra transcript levels, which were associated with a moderate inflammatory profile. Unexpectedly, islets that were isolated from IL-1Ra-knockout mice and pre-treated with hAAT before grafting into wild-type mice yielded an increase in intragraft IL-1Ra expression that was presumably derived from infiltrating host cells, albeit in the absence of hAAT treatment of the host. Indeed, hAAT-pre-treated islets generated hAAT-free conditioned medium that could induce IL-1Ra production in cultured macrophages. Finally, we demonstrated that hAAT promoted a distinct phosphorylation and nuclear translocation pattern for p65, a key transcription factor required for IL-1Ra expression.

Protection against RNA-induced liver damage by myeloid cells requires type I interferon and IL-1 receptor antagonist in mice

Cell types and mechanisms involved in type I interferon (IFN)-mediated anti-inflammatory effects are poorly understood. Upon injection of artificial double-stranded RNA (poly(I:C)), we observed severe liver damage in type I IFN-receptor (IFNAR) chain 1-deficient mice, but not in wild-type (WT) controls. Studying mice with conditional IFNAR ablations revealed that IFNAR triggering of myeloid cells is essential to protect mice from poly(I:C)-induced liver damage. Accordingly, in poly(I:C)-treated WT, but not IFNAR-deficient mice, monocytic myeloid-derived suppressor cells (MDSCs) were recruited to the liver. Comparing WT and IFNAR-deficient mice with animals deficient for the IFNAR on myeloid cells only revealed a direct IFNAR-dependent production of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) that could be assigned to liver-infiltrating cells. Upon poly(I:C) treatment, IFNAR-deficient mice displayed both a severe lack of IL-1RA production and an increased production of proinflammatory IL-1β, indicating a severely imbalanced cytokine milieu in the liver in absence of a functional type I IFN system. Depletion of IL-1β or treatment with recombinant IL-1RA both rescued IFNAR-deficient mice from poly(I:C)-induced liver damage, directly linking the deregulated IL-1β and IL-1RA production to liver pathology. Type I IFN signaling protects from severe liver damage by recruitment of monocytic MDSCs and maintaining a balance between IL-1β and IL-1RA production.

IL-1RN VNTR Polymorphism in Adult Dermatomyositis and Systemic Lupus Erythematosus.

Polymorphisms in the cytokine genes and their natural antagonists are thought to influence the predisposition to dermatomyositis (DM) and systemic lupus erythematosus (SLE). A variable number tandem repeat (VNTR) polymorphism of 86 bp in intron 2 of the interleukin-1 receptor antagonist (IL-1RN) gene leads to the existence of five different alleles which cause differences in the production of both IL-1RA (interleukin-1 receptor antagonist) and IL-1β. The aim of this case-control study was to investigate the association between the IL-1RN VNTR polymorphism and the susceptibility to DM and SLE in Bulgarian patients. Altogether 91 patients, 55 with SLE and 36 with DM, as well as 112 unrelated healthy controls, were included in this study. Only three alleles were identified in both patients and controls ((1) four repeats, (2) two repeats, and (3) five repeats). The IL-1RN*2 allele (P = 0.02, OR 2.5, and 95% CI 1.2–5.4) and the 1/2+2/2 genotypes were found prevalent among the SLE patients (P = 0.05, OR 2.6, and 95% CI 1–6.3). No association was found between this polymorphism and the ACR criteria for SLE as well as with the susceptibility to DM. Our results indicate that the IL-1RN VNTR polymorphism might play a role in the susceptibility of SLE but not DM.

Mature Dendritic Cell Suppression by IL-1 Receptor Antagonist on Retinal Pigment Epithelium Cells

To determine whether retinal pigment epithelial (RPE) cells can inhibit mature dendritic cells (mDCs). Cultured RPE cells were established from C57BL/6 mice. DCs were established from bone marrow cells of normal mice, and mDCc were induced by culture in medium containing granulocyte macrophage-colony-stimulating factor (GM-CSF) and IL-4 in the presence of lipopolysaccharide and TNF-α. Activation of mDCs was assessed by a proliferation assay and ELISA to measure the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-12p40). Expression of major histocompatibility complex (MHC) class II, CD11c, and costimulatory molecules such as CD80, CD86, programmed cell death 1 ligand 1 (PD-L1), and PD-L2 on mDCs or RPE-exposed mDCs was evaluated by immune staining and flow cytometry. Production of IL-1 receptor antagonist (IL-1Ra) by RPE cells was evaluated by oligonucleotide microarray or ELISA. Anti-IL-1Ra neutralizing antibodies or RPE cells from IL-1Ra knockout donors were used for the assay. Cultured RPE cells greatly suppressed the activation of mDCs, especially the production of pro-inflammatory cytokines, and the expression of cell-surface molecules. Moreover, RPE cells significantly suppressed mixed lymphocyte reactions by mDCs. In an examination of immunoregulatory candidate molecules, RPE cells expressed much higher levels of IL-1Ra as compared with control cells, and RPE cells pretreated with recombinant TNF-α and/or IL-1β produced high levels of IL-1Ra. RPE cells in the presence of anti-IL-1Ra antibodies, but not other candidate factors, failed to suppress activation by mDCs. In addition, RPE cells from IL-1Ra null donors failed to suppress mDC activation. Our results suggest that ocular resident cells can produce pro-inflammatory cytokine antagonist that suppresses antigen-presenting cell activation.

Interleukin-6, interleukin-1 beta and interleukin-1 receptor antagonist levels in epileptic seizures

PurposeData are accumulating to support the involvement of inflammatory mechanisms in the pathogenesis and course of epilepsy. MethodsThe aim of this study was to examine seizure-induced changes in plasma concentrations of interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1Ra), and interleukin-1 beta (IL-1β) in 23 patients with epilepsy undergoing a video-electroencephalography (EEG) study. Patients were divided into groups based on epilepsy type as follows: temporal lobe epilepsy (TLE) (n=6), extra-temporal lobe epilepsy (XLE) (n=8) and idiopathic generalised epilepsy (IGE) (n=9). Serum levels of IL-1β, IL-1Ra and IL-6 were measured at baseline, immediately after the epileptic seizure, and at 3h, 6h, 12h and 24h after the seizure. ResultsWe demonstrated a significant increase in plasma levels of IL-6 and IL-1Ra that peaked at 12h into the post-ictal period (p<0.05). IL-1β levels did not differ from the baseline levels. We did not observe any differences in post-ictal cytokine release patterns between the TLE, XLE and IGE groups. ConclusionThe present study confirms the findings that epileptic seizures induce the production of IL-6 and IL-1Ra.

Increased NLRP3-dependent interleukin 1β secretion in patients with familial Mediterranean fever: correlation with MEFV genotype

ObjectivesTo define in patients affected by familial Mediterranean fever (FMF) whether or not interleukin (IL)-1β secretion (1) is enhanced, (2) correlates with the type of MEFV mutation and (3) is...

Intracellular Function of Interleukin-1 Receptor Antagonist in Ischemic Cardiomyocytes

BackgroundLoss of cardiac myocytes due to apoptosis is a relevant feature of ischemic heart disease. It has been described in infarct and peri-infarct regions of the myocardium in coronary syndromes and in ischemia-linked heart remodeling. Previous studies have provided protection against ischemia-induced cardiomyocyte apoptosis by the anti-inflammatory cytokine interleukin-1 receptor-antagonist (IL-1Ra). Mitochondria triggering of caspases plays a central role in ischemia-induced apoptosis. We examined the production of IL-1Ra in the ischemic heart and, based on dual intra/extracellular function of some other interleukins, we hypothesized that IL-1Ra may also directly inhibit mitochondria-activated caspases and cardiomyocyte apoptosis.Methodology/Principal FindingsSynthesis of IL-1Ra was evidenced in the hearts explanted from patients with ischemic heart disease. In the mouse ischemic heart and in a mouse cardiomyocyte cell line exposed to long-lasting hypoxia, IL-1Ra bound and inhibited mitochondria-activated caspases, whereas inhibition of caspase activation was not observed in the heart of mice lacking IL-1Ra (Il-1ra−/−) or in siRNA to IL-1Ra-interfered cells. An impressive 6-fold increase of hypoxia-induced apoptosis was observed in cells lacking IL-1Ra. IL-1Ra down-regulated cells were not protected against caspase activation and apoptosis by knocking down of the IL-1 receptor, confirming the intracellular, receptor-independent, anti-apoptotic function of IL-1Ra. Notably, the inhibitory effect of IL-1Ra was not influenced by enduring ischemic conditions in which previously described physiologic inhibitors of apoptosis are neutralized.Conclusions/SignificanceThese observations point to intracellular IL-1Ra as a critical mechanism of the cell self-protection against ischemia-induced apoptosis and suggest that this cytokine plays an important role in the remodeling of heart by promoting survival of cardiomyocytes in the ischemic regions.

Targeted delivery of cytokine therapy to rheumatoid tissue by a synovial targeting peptide

ObjectivesThe synovial endothelium targeting peptide (SyETP) CKSTHDRLC has been identified previously and was shown to preferentially localise to synovial xenografts in the human/severe combined immunodeficient (SCID) mouse chimera model of...

Deficient production of IL-1 receptor antagonist and IL-6 coupled to oxidative stress in cryopyrin-associated periodic syndrome monocytes

ObjectiveTo determine whether dysregulated production of cytokines downstream of interleukin (IL)-1 participates in the pathophysiology of cryopyrin-associated periodic syndromes (CAPS).MethodsPrimary monocytes from patients with CAPS, unstimulated or after stimulation with...

Airway epithelial cells activate TH2 cytokine production in mast cells through IL-1 and thymic stromal lymphopoietin

Airway epithelial cells are important regulators of innate and adaptive immunity. Although mast cells are known to play a central role in manifestations of allergic inflammation and are found in the epithelium in patients with T(H)2-related diseases, their role is incompletely understood. The objective of this study was to investigate the role of airway epithelial cells in the production of T(H)2 cytokines in mast cells. Normal human bronchial epithelial (NHBE) cells were stimulated with TNF, IL-4, IFN-γ, IL-17A, and double-stranded RNA (dsRNA) alone or in combination. Human mast cells were stimulated with epithelial cell-derived supernatants or cocultured with NHBE cells. T(H)2 cytokine responses were blocked with neutralizing antibodies. Supernatants from IL-4- and dsRNA-stimulated NHBE cells significantly enhanced T(H)2 cytokine production from mast cells. The combination of IL-4 and dsRNA itself or supernatants from NHBE cells stimulated with other cytokines did not activate mast cells, suggesting that mast cell responses were induced by epithelial cell factors that were only induced by IL-4 and dsRNA. Epithelial supernatant-dependent T(H)2 cytokine production in mast cells was suppressed by anti-IL-1 and anti- thymic stromal lymphopoietin (TSLP) and was enhanced by anti-IL-1 receptor antagonist. Similar results were observed in coculture experiments. Finally, we found dsRNA-dependent production of IL-1, TSLP, and IL-1 receptor antagonist in NHBE cells was regulated by T(H) cytokines, and their ratio in NHBE cells correlated with T(H)2 cytokine production in mast cells. Pathogens producing dsRNA, such as respiratory viral infections, might amplify local T(H)2 inflammation in asthmatic patients through the production of TSLP and IL-1 by epithelial cells and subsequent activation of T(H)2 cytokine production by mast cells in the airways.

Mice deficient in hepatocyte‐specific IL‐1Ra show delayed resolution of concanavalin A‐induced hepatitis

Interleukin-1 receptor antagonist (IL-1Ra) is a specific IL-1 inhibitor that possesses anti-inflammatory activities. Several studies in human and mouse suggested a protective role for IL-1Ra in liver inflammation, and we previously demonstrated that hepatocytes produce high levels of IL-1Ra in response to inflammatory challenge in vitro and in vivo. In the present study, we investigated the production and the biological function of hepatocyte-derived IL-1Ra in concanavalin A (ConA)-induced hepatitis in mice. We show that the injured liver produces large amounts of IL-1Ra and that secreted and intracellular IL-1Ra isoforms are produced with different kinetics during the course of hepatitis. By using hepatocyte-specific IL-1Ra-deficient mice (IL-1Ra(ΔH)), we demonstrate that hepatocytes represent the major cellular source of local IL-1Ra. Most interestingly, hepatic necrosis and inflammation were increased in IL-1Ra(ΔH) as compared with wild-type mice during the late phase of the disease, leading to a delayed resolution of hepatitis in IL-1Ra(ΔH) mice. In conclusion, our results show that the local production of IL-1Ra by hepatocytes contributes to the resolution of hepatitis.

Mucosal imbalance of interleukin-1β and interleukin-1 receptor antagonist in canine inflammatory bowel disease

Interleukin (IL)-1β is a key mediator of the inflammatory response. IL-1 receptor antagonist (IL-1Ra) regulates inflammation by functioning as an endogenous inhibitor of IL-1β. A disruption of the balance between IL-1β and IL-1Ra has been identified in human inflammatory bowel disease (IBD). The objective of this study was to determine whether there is an intestinal imbalance of IL-1β and IL-1Ra in canine IBD by comparing expression of IL-1β and IL-1Ra mRNA by real-time RT-PCR and expression of IL-1β and IL-1Ra protein by ELISA in 21 dogs with IBD, 15 dogs with intestinal lymphoma ('inflammatory' controls) and 20 healthy Beagles ('healthy' controls). A significant decrease in the intestinal IL-1Ra:IL-1β ratio of mRNA and protein was observed in IBD cases when compared with healthy control dogs. In contrast, a decrease in IL-1Ra:IL-1β ratio was not observed in dogs with intestinal lymphoma. The IL-1Ra:IL-1β protein ratio was negatively correlated with clinical severity in dogs with IBD. An intestinal imbalance between IL-1β and IL-1Ra production may play a role in the pathogenesis of canine IBD.

Articular inflammation is controlled by myeloid cell-derived interleukin 1 receptor antagonist during the acute phase of arthritis in mice

ObjectivesTo define the cell type (myeloid vs other cells) specific effect of interleukin 1 (IL-1) receptor antagonist (IL-1Ra) deficiency on the acute inflammatory phase of arthritis.MethodsArthritis was induced by K/BxN...

Role of the Gut in Visceral Fat Inflammation and Metabolic Disorders

Role of the Gut in Visceral Fat Inflammation and Metabolic Disorders

IL-1Ra: its role in rheumatoid arthritis

Interleukin-1 (IL-1) is one of the pivotal cytokines in initiating and driving the processes of rheumatoid arthritis (RA), and the body's natural response, IL-1 receptor antagonist (IL-1Ra), has been shown conclusively to block its effects. IL-1 mediate several clinical symptoms of the inflammatory reaction (i.e. fever, pain, sleep disturbances). IL-1 is considered a key mediator in RA joint damage because of its greater capacity (greater than TNF) of increasing matrix degradation by inducing the production of MMPs and PGE2 in synovial cells, as well by its role as mediator of bone and cartilage destruction. In addition, IL-1 decreases the repair process by suppressing matrix synthesis and shows a strong synergism with TNF in inducing many inflammatory genes at both local and systemic level. The induced endogenous production of IL-1Ra, in presence of the RA synovitis, is too low to contrast the high affinity of IL-1 for the cell receptors. Therefore, IL-1Ra presence should result in very effective prevention of IL-1 signal transduction particularly in the inflammatory site. In laboratory and animal studies inhibition of IL-1 by either antibodies to IL-1 or IL-1Ra proved beneficial to the outcome. IL-1Ra is a member of the IL-1 superfamily. The effects of different DMARDs on IL-1Ra levels in RA patients support the important role that selected anticytokine treatments might exert in the pathophysiology of the disease. However, since anti TNF-alpha therapy it is not effective in all RA patients, nor does it fully control the arthritic process in affected joints of good responders and complete TNF suppression should be avoided, the combined treatment with intermediate doses of TNF and IL-1 blockers, reaching synergistic suppression of arthritis, seems warranted in RA.

CS10-5. Deficient IL-1 Receptor antagonist production by monocytes from patients carrying mutations in the NLRP3 gene

CS10-5. Deficient IL-1 Receptor antagonist production by monocytes from patients carrying mutations in the NLRP3 gene

Interleukin 1 receptor antagonist mediates the beneficial effects of systemic interferon beta in mice: implications for rheumatoid arthritis

ObjectivesInterferon beta (IFNβ) therapy is effective in multiple sclerosis and murine models of arthritis. Surprisingly, systemic IFNβ treatment induces only minimal improvement in rheumatoid arthritis (RA). To explain this paradox,...

Modulation of interleukin-1β-induced inflammatory responses by a synthetic cationic innate defence regulator peptide, IDR-1002, in synovial fibroblasts

IntroductionInnate defence regulator (IDR) peptides are synthetic cationic peptides, variants of naturally occurring innate immune effector molecules known as host defence peptides. IDR peptides were recently demonstrated to limit infection-associated inflammation selectively without compromising host innate immune functions. This study examined the impact of a 12-amino acid IDR peptide, IDR-1002, in pro-inflammatory cytokine interleukin (IL)-1β-induced responses in synovial fibroblasts, a critical cell type in the pathogenesis of inflammatory arthritis.MethodsHuman fibroblast-like synoviocytes (FLS) were stimulated with IL-1β in the presence and absence of IDR-1002. Production of enzyme matrix metalloproteinase-3 (MMP-3) and IL-1-receptor antagonist (IL-1RA) was monitored by enzyme-linked immunosorbent assay (ELISA), and various chemokines were evaluated by using multiplex cytometric bead array. Transcriptional responses were analyzed by quantitative real-time PCR. The impact on IL-1β-induced proteome was investigated by quantitative proteomics by using isobaric tags. IL-1β-induced pathways altered by IDR-1002 implicated by the proteomics analyses were further investigated by using various immunochemical assays. Cellular uptake of the peptide was monitored by using a biotinylated IDR-1002 peptide followed by microscopy probing with streptavidin-Alexa Fluor.ResultsThis study demonstrated that IDR-1002 suppressed the production of IL-1β-induced MMP-3 and monocyte chemotactic protein-1 (MCP-1); in contrast, IDR-1002 enhanced the production of IL-1RA, without neutralizing all chemokine responses. IDR-1002 altered the IL-1β-induced proteome primarily by altering the expression of members of nuclear factor kappa-B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways. The proteomics data also suggested that IDR-1002 was altering the transcription factor HNF-4α-mediated responses, known to be critical in metabolic regulation. With various immunochemical assays, it was further demonstrated that IL-1β-induced NF-κB, JNK, and p38 mitogen-activated protein kinase (MAPK) activations were significantly suppressed by IDR-1002.ConclusionsThis study demonstrates the ability of an innate immune-modulatory IDR-peptide to influence the IL-1β-induced regulatory pathways and selectively to suppress inflammatory responses in synovial fibroblasts. The results of this study provide a rationale for examining the use of IDR-peptides as potential therapeutic candidates for chronic inflammatory diseases such as inflammatory arthritis.