Loss of T follicular regulatory cell-derived IL-1R2 augments germinal center reactions via increased IL-1

Inappropriate immune activity is key in the pathogenesis of multiple diseases, and it is typically driven by excess inflammation and/or autoimmunity. IL-1 is often the effector owing to its powerful role in both innate and adaptive immunity, and, thus, it is tightly controlled at multiple levels. IL-1R2 antagonizes IL-1, but effects of losing this regulation are unknown. We found that IL-1R2 resolves inflammation by rapidly scavenging free IL-1. Specific IL-1R2 loss in germinal center (GC) T follicular regulatory (Tfr) cells increased the GC response after a first, but not booster, immunization, with an increase in T follicular helper (Tfh) cells, GC B cells, and antigen-specific antibodies, which was reversed upon IL-1 blockade. However, IL-1 signaling is not obligate for GC reactions, as WT and Il1r1-/- mice showed equivalent phenotypes, suggesting that GC IL-1 is normally restrained by IL-1R2. Fascinatingly, germline Il1r2-/- mice did not show this phenotype, but conditional Il1r2 deletion in adulthood recapitulated it, implying that compensation during development counteracts IL-1R2 loss. Finally, patients with ulcerative colitis or Crohn's disease had lower serum IL-1R2. All together, we show that IL-1R2 controls important aspects of innate and adaptive immunity and that IL-1R2 level may contribute to human disease propensity and/or progression.

Intracellular IL-1alpha-binding proteins contribute to biological functions of endogenous IL-1alpha in systemic sclerosis fibroblasts

The aberrant production of precursor IL-1alpha (pre-IL-1alpha) in skin fibroblasts that are derived from systemic sclerosis (SSc) is associated with the induction of IL-6 and procollagen, which contributes to the fibrosis of SSc. However, little is understood about how intracellular pre-IL-1alpha regulates the expression of the other molecules in fibroblasts. We report here that pre-IL-1alpha can form a complex with IL-1alpha-binding proteins that is translocated into the nuclei of fibroblasts. Immunoprecipitation that used anti-human IL-1alpha Ab and (35)S-labeled nuclear extracts of fibroblasts showed three specific bands (approximately equal to 31, 35, and 65 kDa). The 31-kDa molecule was identified as pre-IL-1alpha, and the 35- and 65-kDa molecules might be pre-IL-1alpha-binding proteins. A partial sequencing for the 10 aa from the N-terminals of the molecules showed 100% homology for HAX-1 (HS1-associated protein X-1) and IL-1 receptor type II (IL-1RII). Suppression of the genes of HAX-1 or IL-1RII induced the inhibitory effects of IL-1 signal transduction, including production of IL-6 and procollagen, by fibroblasts. In particular, pre-IL-1alpha was not translocated into the nucleus by an inhibition of HAX-1. These findings reveal that nuclear localization of pre-IL-1alpha depends on the binding to HAX-1 and that biological activities might be elicited by the binding to both HAX-1 and IL-1RII in SSc fibroblasts.

Selective modulation of Hedgehog/GLI target gene expression by epidermal growth factor signaling in human keratinocytes

Hedgehog (HH)/GLI signaling plays a critical role in epidermal development and basal cell carcinoma. Here, we provide evidence that epidermal growth factor receptor (EGFR) signaling modulates the target gene expression profile of GLI transcription factors in epidermal cells. Using expression profiling and quantitative reverse transcriptase PCR, we identified a set of 19 genes whose transcription is synergistically induced by GLI1 and parallel EGF treatment. Promoter studies of a subset of GLI/EGF-regulated genes, including the genes encoding interleukin-1 antagonist IL1R2, Jagged 2, cyclin D1, S100A7, and S100A9, suggest convergence of EGFR and HH/GLI signaling at the level of promoters of selected direct GLI target genes. Inhibition of EGFR and MEK/ERK but not of phosphatidylinositol 3-kinase/AKT abrogated synergistic activation of GLI/EGF target genes, showing that EGFR can signal via RAF/MEK/ERK to cooperate with GLI proteins in selective target gene regulation. Coexpression of the GLI/EGF target IL1R2, EGFR, and activated ERK1/2 in human anagen hair follicles argues for a cooperative role of EGFR and HH/GLI signaling in specifying the fate of outer root sheath (ORS) cells. We also show that EGF treatment neutralizes GLI-mediated induction of epidermal stem cell marker expression and provide evidence that EGFR signaling is essential for GLI-induced cell cycle progression in epidermal cells. The results suggest that EGFR signaling modulates GLI target gene profiles which may play an important regulatory role in ORS specification, hair growth, and possibly cancer.

UBD, a downstream element of FOXP3, allows the identification of LGALS3, a new marker of human regulatory T cells

Here, we report the identification of the ubiquitin-like gene UBD as a downstream element of FOXP3 in human activated regulatory CD4(+)CD25(hi) T cells (T(reg)). Retroviral transduction of UBD in human allo-reactive effector CD4(+) T helper (T(h)) cells upregulates CD25 and mediates downregulation of IL4 and IL5 expression similar to overexpression of FOXP3. Moreover, UBD impairs T(h) cell proliferation without upregulation of FOXP3 and impairs calcium mobilization. In the presence of ionomycin, overexpression of UBD in T(h) cells leads to the induction of IL1R2 that resemble FOXP3-transduced T(h) cells and naturally derived T(reg) cells. A comparison of the transcriptome of FOXP3- and UBD-transduced T(h) cells with T(reg) cells allowed the identification of the gene LGALS3. However, high levels of LGALS3 protein expression were observed only in human CD4(+)CD25(hi) derived T(reg) cells and FOXP3-transduced T(h) cells, whereas little was induced in UBD-transduced T(h) cells. Thus, UBD contributes to the anergic phenotype of human regulatory T cells and acts downstream in FOXP3 induced regulatory signaling pathways, including regulation of LGALS3 expression. High levels of LGALS3 expression represent a FOXP3-signature of human antigen-stimulated CD4(+)CD25(hi) derived regulatory T cells.

Analysis of interleukin (IL)-1beta IL-1 receptor antagonist, soluble IL-1 receptor type II and IL-1 accessory protein in HCV-associated lymphoproliferative disorders

Hepatitis C virus (HCV) causes hepatitis, liver cirrhosis and hepatocellular carcinoma, and may also induce type II mixed cryoglobulinemia syndrome (MC), a disease characterized by clonal B-cell lymphoproliferations that can evolve into non-Hodgkin's lymphoma (NHL). Interleukin-1 (IL-1) is a cytokine that plays an important role in initiating the cascade of events of immunoinflammatory responses through costimulation of T lymphocytes, B-cell proliferation, induction of adhesion molecules and stimulation of the production of other inflammatory cytokines. The role of IL-1 in immunoinflammatory responses is highlighted by the presence of endogenous regulators (IL-1 receptor antagonist, soluble receptors type 1 and II, human IL-1 accessory protein) that, when secreted into the blood stream may serve as endogenous regulators of IL-1 action. The aim of this study was to evaluate whether abnormalities in the blood levels of IL-1beta IL-1 receptor antagonist, soluble IL-1 receptor type II and human IL-1 accessory protein in HCV+ patients are associated with development of MC and/or NHL. Relative to healthy controls, we observed: i) an increase in the circulating levels of IL-1beta in HCV+ patients simultaneously affected by NHL; ii) increased levels of IL-1 accessory protein in patients singly infected by HCV; iii) increase of IL-1 receptor antagonist in HCV+ patients and in those affected also by NHL with or without MC; iv) a homogeneous increase of sIL-1R type II in all the subgroup of patients. These data indicate that an attempt to increased circulating levels of IL-1 inhibitors occurs at different extent in the course of HCV infection as well as in its progression to NHL and/or MC.

Molecular characterization and functional expression of equine interleukin-1 type I and type II receptor cDNAs

cDNA generated from lipopolysaccharide-stimulated equine peripheral blood mononuclear cells was used to amplify and clone type I and type II equine interleukin-1 receptors (IL-1RI and IL-1RII) using primers derived from semi-conserved regions between human and mouse IL-1RI and IL-1RII sequences, respectively. 5' and 3' terminal sequences of equine IL-1RI and IL-1RII were amplified by 5' and 3' rapid amplification of cDNA ends. The deduced amino acid sequence of equine IL-1RI demonstrated 77, 64 and 63% similarity with human, mouse and rat sequences, respectively. The predicted amino acid sequence of equine IL-1RII demonstrated 70, 60 and 58% similarity with human, mouse and rat sequences, respectively. Recombinant equine soluble IL-1RI and IL-1RII produced in insect cells bound recombinant equine IL-1alpha and IL-1beta. Furthermore, both receptors suppressed the growth inhibitory activities of equine IL-1alpha and IL-1beta toward A375 cells in a dose-dependent manner, indicating that the present equine IL-1RI and IL-1RII cDNA encodes biologically active proteins.

Interleukin-1 receptor antagonist is upregulated during diet-induced obesity and regulates insulin sensitivity in rodents

AIMS/HYPOTHESIS

The IL-1 receptor antagonist (IL-1Ra) is an anti-inflammatory cytokine known to antagonise the actions of IL-1. We have previously shown that IL-1Ra is markedly upregulated in the serum of obese patients, is correlated with BMI and insulin resistance, and is overexpressed in the white adipose tissue (WAT) of obese humans. The aim of this study was to examine the role of IL-1Ra in the regulation of glucose homeostasis in rodents.

METHODS

We assessed the expression of genes related to IL-1 signalling in the WAT of mice fed a high-fat diet, as well as the effect of Il1rn (the gene for IL-1Ra) deletion and treatment with IL-1Ra on glucose homeostasis in rodents.

RESULTS

We show that the expression of Il1rn and the gene encoding the inhibitory type II IL-1 receptor was upregulated in diet-induced obesity. The blood insulin:glucose ratio was significantly lower in Il1rn ( -/- )animals, which is compatible with an increased sensitivity to insulin, reinforced by the fact that the insulin content and pancreatic islet morphology of Il1rn ( -/- ) animals were normal. In contrast, the administration of IL-1Ra to normal rats for 5 days led to a decrease in the whole-body glucose disposal due to a selective decrease in muscle-specific glucose uptake.

CONCLUSIONS/INTERPRETATION

The expression of genes encoding inhibitors of IL-1 signalling is upregulated in the WAT of mice with diet-induced obesity, and IL-1Ra reduces insulin sensitivity in rats through a muscle-specific decrease in glucose uptake. These results suggest that the markedly increased levels of IL-1Ra in human obesity might contribute to the development of insulin resistance.

Development of a sandwich ELISA assay for measuring bovine soluble type II IL-1 receptor (IL1R2) concentration in serum and milk

The IL1R is composed of two kinds of molecule, type I (IL1R I) and type II (IL1R2). IL1R1 contributes to IL-1 signaling, whereas the IL1R2 has no signaling property and acts as a decoy for IL-1. In this study, we developed a bovine IL1R2-specific sandwich ELISA to examine the sIL1R2 concentration in serum and milk from dairy cows. The concentration of colostral IL-1beta was examined to estimate the correlation to sIL1R2. The results showed that the sIL1R2 concentration in sera and milk changes with the stages of lactation. The serum sIL1R2 concentrations were 5.56+/-0.69 ng/ml (colostrum), 3.14+/-0.72 ng/ml (the early stage of lactation) and 5.76+/-1.25 ng/ml (the late stage of lactation). The milk sIL1R2 concentrations were 1.83+/-0.47 ng/ml (colostrum), 0.73+/-0.22 ng/ml (the early stage of lactation) and 2.92+/-0.56 ng/ml (the late stage of lactation). The concentrations of IL1R2 in sera and milk were significantly higher at the late stage of lactation and colostrum than that of the early stage of lactation. The reduction rates of sIL1R2 levels from the colostrum to the early stage of lactation were 43.6% (serum) and 61% (whey). IL-1beta was detected in all the colostrum (995.9+/-346.6 ng/ml). Significant correlation was observed between the levels of colostral IL-1beta and IL1R2 (r=0.75).

Cytokine responses of human gingival fibroblasts to Actinobacillus actinomycetemcomitans cytolethal distending toxin

Actinobacillus actinomycetemcomitans is implicated in the pathogenesis of localized aggressive periodontitis, and has the capacity to express a cytolethal distending toxin (Cdt). Gingival fibroblasts (GF) are resident cells of the periodontium, which can express several osteolytic cytokines. The aims of this study were a) to investigate the role of Cdt in A. actinomycetemcomitans-induced expression of osteolytic cytokines and their cognate receptors in GF and b) to determine if the previously demonstrated induction of receptor activator of NFkappaB ligand (RANKL) by A. actinomycetemcomitans is mediated by these pro-inflammatory cytokines or by prostaglandin E(2) (PGE(2)). A. actinomycetemcomitans clearly induced interleukin (IL)-6, IL-1beta, and to a minimal extent, tumor necrosis factor (TNF)-alpha mRNA expression. At the protein level, IL-6 but not IL-1beta or TNF-alpha expression was stimulated. The mRNA expression of the different receptor subtypes recognizing IL-6, IL-1beta and TNF-alpha was not affected. A cdt-knockout strain of A. actinomycetemcomitans had similar effects on cytokine and cytokine receptor mRNA expression, compared to its parental wild-type strain. Purified Cdt stimulated IL-6, but not IL-1beta or TNF-alpha protein biosynthesis. Antibodies neutralizing IL-6, IL-1 or TNF-alpha, and the PGE(2) synthesis inhibitor indomethacin, did not affect A. actinomycetemcomitans-induced RANKL expression. In conclusion, a) A. actinomycetemcomitans induces IL-6 production in GF by a mechanism largely independent of its Cdt and b) A. actinomycetemcomitans-induced RANKL expression in GF occurs independently of IL-1, IL-6, TNF-alpha, or PGE(2).

Concentrations of interleukin (IL)-1alpha, IL-1 soluble receptor type II (IL-1 sRII) and IL-1 receptor antagonist (IL-1 Ra) in the peritoneal fluid and serum of infertile women with endometriosis

OBJECTIVE

Endometriosis is an immune system-related gynaecological disease, characterised by an increase in number and activation of peritoneal macrophages. One of macrophage-derived factors is interleukin (IL)-1. The effects of IL-1 are inhibited by IL-1 receptor type II (IL-1 RII), soluble forms of IL-1 RII (IL-1 sRII) and IL-1 receptor antagonist (IL-1 Ra). The aim of our work was to study the IL-1alpha, IL-1 sRII and IL-1 Ra levels in the peritoneal fluid (PF) and serum of women with endometriosis in relation to stage of disease.

STUDY DESIGN

Concentrations of IL-1alpha, IL-1 sRII and IL-1 Ra were measured by ELISA assay in the PF and serum of 58 women; 43 with and 15 without endometriosis (control group).

RESULTS

Elevated PF and serum IL-1alpha and IL-1 Ra levels in the women with endometriosis in comparison with the control group were observed. IL-1 sRII levels in PF and serum were higher in the controls than in the women with endometriosis. Concentrations of IL-1alpha and IL-1 sRII were higher in advanced endometriosis, but higher IL-1 Ra was observed in the early stage of the disease.

CONCLUSION

Impairment of regulation IL-1 activity in the peritoneal fluid and serum of women with endometriosis may play an important role in the pathogenesis and development of the disease.

Soluble interleukin-1 receptor type II, IL-18 and caspase-1 in mild cognitive impairment and severe Alzheimer's disease

In the present study, we have determined levels of soluble interleukin-1 (IL-1) receptor type II (sIL-1RII), interleukin-18 (IL-18) and caspase-1 in cerebrospinal fluid and serum from mild cognitive impairment patients that later progressed to Alzheimer's disease (AD) and severe AD patients. Previous studies have shown that a chronic local inflammatory process is a part of AD neuropathology. In this process, activated microglial production of IL-1 seems to play an important role. In a previous study, we have shown increased levels of sIL-1RII in CSF from AD patients in a mild-moderate disease stage. In the present study, we found no significant differences in CSF or serum levels of sIL-1RII in either mild cognitive impairment or advanced AD patients as compared to control subjects. Likewise, there was no significant difference between mild cognitive impairment and severe AD patients. The same was true for caspase-1 and IL-18 serum levels, whereas CSF levels of caspase-1 and IL-18 were below detection limits. Our data indicate that the IL-1 system is relatively intact in the early and late stages of AD.

Differential regulation of type I and type II interleukin-1 receptors in focal brain inflammation

Most pathologies of the brain have an inflammatory component, associated with the release of cytokines such as interleukin-1beta (IL-1beta) from resident and infiltrating cells. The IL-1 type I receptor (IL-1RI) initiates a signalling cascade but the type II receptor (IL-1RII) acts as a decoy receptor. Here we have investigated the expression of IL-1beta, IL-1RI and IL-1RII in distinct inflammatory lesions in the rat brain. IL-1beta was injected into the brain to generate an inflammatory lesion in the absence of neuronal cell death whereas neuronal death was specifically induced by the microinjection of N-methyl-D-aspartate (NMDA). Using TaqMan RT-PCR and ELISA, we observed elevated de novo IL-1beta synthesis 2 h after the intracerebral microinjection of IL-1beta; this de novo IL-1beta remained elevated 24 h later. There was a concomitant increase in IL-1RI mRNA but a much greater increase in IL-1RII mRNA. Immunostaining revealed that IL-1RII was expressed on brain endothelial cells and on infiltrating neutrophils. In contrast, although IL-1beta and IL-1RI were elevated to similar levels in response to NMDA challenge, the response was delayed and IL-1RII mRNA expression was unchanged. The lesion-specific expression of IL-1 receptors suggests that the receptors are differentially regulated in a manner not directly related to the endogenous level of IL-1 in the CNS.

Scan-Rate-Dependent Melting Transitions of Interleukin-1 Receptor (Type II): Elucidation of Meaningful Thermodynamic and Kinetic Parameters of Aggregation Acquired from DSC Simulations

The role of thermal unfolding as it pertains to thermodynamic properties of proteins and their stability has been the subject of study for more than 50 years. Moreover, exactly how the unfolding properties of a given protein system may influence the kinetics of aggregation has not been fully characterized. In the study of recombinant human Interleukin-1 receptor type II (rhuIL-1R(II)) aggregation, data obtained from size exclusion chromatography and differential scanning calorimetry (DSC) were used to model the thermodynamic and kinetic properties of irreversible denaturation. A break from linearity in the initial aggregation rates as a function of 1/T was observed in the vicinity of the melting transition temperature (T(m) approximately 53.5 degrees C), suggesting significant involvement of protein unfolding in the reaction pathway. A scan-rate dependence in the DSC experiment testifies to the nonequilibrium influences of the aggregation process. A mechanistic model was developed to extract meaningful thermodynamic and kinetic parameters from an irreversibly denatured process. The model was used to simulate how unfolding properties could be used to predict aggregation rates at different temperatures above and below the T(m) and to account for concentration dependence of reaction rates. The model was shown to uniquely identify the thermodynamic parameters DeltaC(P) (1.3 +/- 0.7 kcal/mol-K), DeltaH(m) (74.3 +/- 6.8 kcal/mol), and T(m) with reasonable variances.

IL-1beta-mediated innate immunity is amplified in the db/db mouse model of type 2 diabetes

Chronic inflammation appears to play a critical role in type 2 diabetes and its complications. Here we tested the hypothesis that this inflammatory dysregulation affects the IL-1beta system and has functional consequences in the brain. Diabetic, db/db, and nondiabetic, db/+, mice were administered i.p. LPS, a potent cytokine inducer, at a dose of 100 microg/kg/mouse. db/db mouse innate immune-associated sickness behavior was 14.8, 33, 44.7, and 34% greater than that of db/+ mice at 2, 4, 8, and 12 h, respectively. When a fixed dose of LPS was used (5 microg/mouse), db/db mouse sickness was again enhanced 18.4, 22.2, and 14.5% at 4, 8, and 12 h as compared with db/+ mice. In diabetic mice, peritoneal macrophages produced more IL-1beta in response to LPS, and peritoneal levels of IL-1beta induced by LPS were increased. Importantly, IL-1R antagonist and type 2 IL-1 receptor (IL-1R2) failed to up-regulate in response to LPS in db/db mice. Finally, both peripheral and central administration of IL-1beta, itself, induced sickness in db/db mice that mimicked the effects of peripheral LPS and was significantly greater than that seen in db/+ mice. Taken together, these results indicate that IL-1beta-mediated innate immunity is augmented in db/db mice both at the periphery and in the brain, and the mechanism is due to diabetes-associated loss of IL-1beta counterregulation.

Increased soluble interleukin-1 receptor type II proteolysis in the endometrium of women with endometriosis

Numerous functional changes were observed in the intrauterine endometrial tissue of women with endometriosis. Our previous studies revealed a marked decrease in the expression of interleukin-1 receptor type 2 (IL-1RII), a decoy receptor known for its ability to buffer IL-1 effects. The aim of the present study was to assess whether post-translational mechanisms such as proteolysis may contribute to the down-regulation of IL-1RII levels. Our data showed that soluble IL-1RII (sIL-1RII) concentrations released by freshly cultured endometrial tissue were significantly lower in women with endometriosis than in normal women (P < 0.01) and further revealed a statistically significant correlation between increased proteolysis and decreased sIL-1RII levels (P < 0.05; r = -0.47). (125)I-labelled soluble recombinant human IL-1RII ([(125)I]srhIL-1RII) was significantly more degraded in culture supernatant of tissues from women with endometriosis compared to normal women (P < 0.05), and natural tissue inhibitor of matrix metalloproteinase (TIMP)-1 inhibited [(125)I]srhIL-1RII degradation. Incubation of srhIL-1RII with active rhMMP-9 resulted in a dose-dependent degradation of srhIL-1RII as analysed by western blotting. Dual immunofluorescence showed an increased immunostaining for matrix metalloproteinase-9 in situ in the endometrial tissue of women with endometriosis compared to normal women and a decreased immunostaining for IL-1RII. The present study showed a reduced release of sIL-1RII by the endometrial tissue of women with endometriosis and revealed a proteolytic post-translational mechanism which may be involved in the down-regulation of IL-1RII levels. This may enhance IL-1-mediated activation of endometrial cells and contribute to the local immuno-inflammatory process observed in endometriosis patients.

Evolution of interleukin-18 binding proteins and interleukin-1 receptor, type II proteins

Interleukin-18 (IL-18) is one of the pivotal cytokines controlling the defense mechanism called inflammation. As a first step to develop proteins for controlling the IL-18 level, we initiated a study of IL-18-binding proteins (IL-18BPs). Twenty-four IL-18BP family members, 11 from vertebrates and 13 from chordopoxviruses, were picked from the NCBI database. Eight of these vertebrate IL-18BPs and two of the chordopoxvirus IL18-BPs were identified here and characterized as new members of the IL-18BP family. Their IL-18 binding domains were aligned and the distribution of highly conserved critical amino acid residues was analyzed and used to construct a phylogenetic tree. From this tree it was inferred that at least two independent events created two different ancestral viral IL-18BP genes by retroposition of IL-18BP genes from the vertebrate lineage. These two events are estimated to have occurred after an ancient mammalian IL-18BP gene diverged from birds, and before the mammalian IL-18BP gene diverged into human, ungulate and rodent IL-18BP genes. Moreover, our results suggest that IL-18BP and interleukin-1 receptor, type II (IL-1R2) had a common ancestral gene and diverged from the ancestral gene into IL-18BP and IL-1R2 genes in the fish period.

Contribution of tumour necrosis factor alpha and interleukin (IL) 1beta to IL6 production, NF-kappaB nuclear translocation, and class I MHC expression in muscle cells: in vitro regulation with specific cytokine inhibitors

OBJECTIVE

To evaluate the effect of tumour necrosis factor alpha (TNFalpha), interleukin (IL) 1beta, and their respective inhibitors the p75 TNFalpha soluble receptor (sTNFR) and the type II sIL1betaR (sIL1RII) on whole muscle and isolated myoblast activation.

METHODS

Normal muscle samples were stimulated for 7 days with TNFalpha alone or in combination with IL1beta, and myoblasts from these samples for 48 hours. IL6 production was measured by ELISA. Nuclear translocation of NF-kappaB was analysed by immunofluorescent staining and class I MHC expression by FACS.

RESULTS

TNFalpha and IL1beta induced IL6 production by normal muscle samples and myoblasts, the action of TNFalpha being more potent on muscle samples. Their soluble receptors (1 microg/ml) decreased this production. Suboptimal concentrations of TNFalpha and IL1beta induced NF-kappaB translocation. sTNFR markedly down regulated TNFalpha-induced translocation while sIL1RII was less potent on IL1beta-induced activation. NF-kappaB translocation induced by the combination of optimal concentrations of TNFalpha and IL1beta was completely inhibited by their soluble receptors. TNFalpha and to a lesser extent IL1beta induced class I MHC expression by myoblasts and this effect was completely inhibited by their respective soluble receptors.

CONCLUSION

These results suggest that TNFalpha and IL1beta should be targeted for myositis treatment.

Soluble cytokine receptor treatment in experimental orthodontic tooth movement in the rat

Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha), are believed to play a role in the biological processes involved in the course of orthodontic tooth movement and especially in root resorption. The inhibition of cytokine activity, e.g. by soluble receptors, could be beneficial in reducing this unwanted side-effect. The aim of this study was to investigate the role of cytokines IL-1 and TNF-alpha in the course of experimentally induced tooth movement. The upper left first molar was moved orthodontically in 80 male Wistar rats using a coil spring with a force of 0.5 N. Starting at day -1, three groups of 20 animals each received daily intraperitoneal injections (ip) of 2 ml of 1 mug/ml soluble receptors (a) to IL-1(sIL-RII), (b) to TNF-alpha (sTNF-alpha-RI) and (c) a combination of (a) and (b). Twenty animals served as the control. After 3, 6, 9 and 12 days, the animals were killed in groups of five. The amount of tooth movement was registered and the maxillae were prepared for histological and histomorphometric analysis. Osteoclasts and odontoclasts were identified using tartrate-resistant acid phosphatase (TRAP) histochemistry. The amount of tooth movement was reduced in all receptor-treated groups by approximately 50 per cent. At the same time, the number of TRAP-positive cells on the desmodontal bone surface and on the surface of the roots was reduced. Thus, systemic application of soluble receptors to IL-1 and TNF-alpha following experimental induction of tooth movement in the rat reduced the number of osteoclasts as well as odontoclasts.

Imbalance between interleukin-1 agonists and antagonists: relationship to severity of inflammatory bowel disease

Interleukin (IL)-1 is a key mediator in the pathogenesis of inflammatory bowel disease (IBD). Naturally occurring IL-1 modulators include IL-1 receptor antagonist (IL-1Ra), IL-1 soluble receptor Type I (IL-1sRI), IL-1sRII and IL-1 receptor accessory protein (AcP). Systemic and mucosal levels of IL-1 soluble receptors remain unknown in IBD. Plasma or colonic tissues were obtained from 185 consecutive unselected patients with Crohn's disease (CD) or ulcerative colitis (UC) and from 52 control subjects. Plasma and colonic explant culture supernatants were assessed for IL-1alpha, IL-1beta, IL-1Ra, IL-1sRI and IL-1sRII. Plasma IL-1Ra levels were higher in UC (+93%) than in healthy subjects. IL-1alpha and IL-1beta were not detected. IL-1sRII levels were marginally lower in CD (-10%) and UC (-9%), whereas IL-1sRI levels were elevated in CD (+28%) only. Plasma IL-1sRI levels correlated positively (P < 0.01) with Crohn's disease activity index (r = 0.53), C-reactive protein (r = 0.46) and alpha1-acid glycoprotein (r = 0.42). In colonic explant cultures, IL-1alpha and IL-1Ra levels were elevated in non-lesional (+233% and +185% respectively) and lesional CD (+353% and +1069%), lesional UC (+604% and +1138%), but not in non-lesional UC. IL-1beta was elevated in lesional UC (+152%) and CD (+128%). In contrast, IL-1sRII levels were elevated in non-lesional CD (+65%), but remained unchanged in lesional CD, non-lesional and lesional UC. IL-1sRI levels did not differ between patient and control groups. These results indicate that (i) the proinflammatory moiety IL-1sRI is a systemic marker of inflammation and activity in CD and (ii) local shedding of the functional antagonist IL-1sRII may dampen colonic inflammation in CD, but not in UC.

Transcriptional pattern analysis of adrenergic immunoregulation in mice. Twelve hours norepinephrine treatment alters the expression of a set of genes involved in monocyte activation and leukocyte trafficking

We investigated in vivo effects of norepinephrine (NE) on the transcription of 200 immunologically relevant genes in the mouse. Balb/c mice were s.c. implanted with NE containing retard tablets. Twelve hours later, splenic mRNA was prepared and hybridized onto cDNA microarrays containing the sequences of the major cytokines, their receptors and all CD-antigens of the mouse. Consistent results were obtained with a set of five genes: in the NE-treated animals four genes (CXCR4, VCAM1, IL-1R2, CD 14) were found 2-8 fold upregulated as compared to sham treated animals, whereas the gene for CCR3 was downregulated (< 0.5 fold). The findings were confirmed using quantitative reverse transcriptase Real Time PCR. These first results prove the usefulness of gene microarray technology towards transcription pattern analysis in neuroimmune interactions. Furthermore, they support the relevance of catecholamines in the regulation of leukocyte migration and the inflammatory response.

Down-regulation of interleukin-1 receptor type 1 expression causes the dysregulated expression of CXC chemokines in endometriotic stromal cells: a possible mechanism for the altered immunological functions in endometriosis

To evaluate the involvement of chemokines in the pathogenesis of endometriosis, we investigated the expression of CXC chemokines in cultured ovarian endometriotic cyst stromal cells (ECSC), endometrial stromal cells with endometriosis (ESCwE), and normal endometrial stromal cells (NESC). Using ELISA, TNF-alpha significantly enhanced the production of IL-8, growth-related oncogene alpha, and epithelial neutrophil-activating peptide-78 in all cases of ECSC (n = 10), ESCwE (n = 6), and, NESC (n = 10). IL-1beta did not affect the production of these chemokines in eight of 10 cases of ECSC. In contrast, IL-1beta significantly enhanced the expression of these chemokines in all cases of ESCwE (n = 6) and NESC (n = 10). Western blot analysis revealed down-regulation of expression of IL-1 receptor type 1 (IL-1-R1) in all cases of ECSC with low response to IL-1beta (n = 8). In contrast, significant IL-1-R1 expression was detected in all cases of NESC. Although IL-1-R1 expression was detected in all cases of ESCwE (n = 6), its expression in ESCwE tended to decrease compared with that in NESC. Moreover, phosphorylation of inhibitor kappaB-alpha was detected in all cases of ESCwE and NESC after stimulation with IL-1beta, but not in ECSC with low response to IL-1beta (n = 8). In contrast, significant IL-1-R2 expression was detected in all cases of ECSC, ESCwE, and NESC. The present findings suggest that the dysregulation of IL-1/IL-1-R system relates to immunological dysfunction in endometriosis. The alteration of the CXC chemokines expression may be important for elucidation of the pathogenesis of endometriosis.

Determinants of plasma leptin concentration in postmenopausal women

This investigation examined the influence of hormone replacement therapy on plasma leptin concentrations in postmenopausal women and sought to determine if a relationship existed between plasma leptin, the thermoregulatory cytokine interleukin-1 (IL-1), and basal body temperature. Twenty-two women (54-71 years of age) were studied: eight were not taking hormone replacement, seven took oral estrogen only, and seven took oral estrogen plus progestin. Morning oral temperature, plasma leptin concentration, and mononuclear cell secretion of IL-1beta, IL-1 receptor antagonist (IL-1Ra), and soluble IL-1 receptor type II (sIL-1RII) were measured. Plasma leptin concentrations were not affected by hormone replacement therapy, but were inversely related to years since menopause (R = -0.48, P = 0.02) and were proportional to IL-1 activity (the balance of IL-1beta/IL-1Ra secretion, R = 0.69, P = 0.001). Moreover, morning oral temperature was positively related to plasma leptin (P = 0.03), after stratifying by progestin intake. These results support the concept that basal body temperature is regulated by a network of endocrine and immune mediators that are significantly influenced by age.

IL-1 beta, IL-1 receptor antagonist and soluble type II IL-1 receptor in synovial fluid of patients with temporomandibular disorders

Among the members of the interleukin-1 (IL-1) family, IL-1 beta, which is a major agonist, has been detected in synovial fluid (SF) of the temporomandibular joint (TMJ) of patients with temporomandibular joint disorders (TMD). However, there is little knowledge regarding suppressive molecules, such as IL-1 receptor antagonist (IL-1ra) and the soluble form of type II IL-1 receptor (sIL-1RII), in TMD patients. The aim of this study was to investigate the levels of IL-1 beta, IL-1ra and sIL-1RII in the TMJ SF of patients with TMD and their relationship. Fifty-two SF samples from TMD patients and nine samples from asymptomatic volunteers were examined. Detected levels of IL-1 beta and sIL-1RII were significantly higher in the TMD group compared with the volunteer group. There was no significant difference in IL-1ra levels between the TMD and volunteer groups. The IL-1 beta/IL-1ra ratio in the TMD group, however, was higher than that in the volunteer group. In the TMD group, positive correlations were found between IL-1 beta and IL-1ra, IL-1ra and sIL-1RII, and IL-1 beta and sIL-1RII. In addition to increased IL-1 beta, development of TMD may also lead to decreased IL-1ra and increased sIL-1RII in response to increasing IL-1.

Interleukin-1 (IL-1alpha and IL-1beta) and its receptors (IL-1RI, IL-1RII, and IL-1Ra) in prostate carcinoma

BACKGROUND

The principal components of the interleukin-1 (IL-1) family are two secreted factors (IL-1alpha and IL-1beta), two transmembrane receptors (IL-1RI [biologically active] and IL-1RII [inert receptor]), and a natural antagonist receptor of IL-1 function (IL-1Ra). Changes in the expression pattern of these IL-1 members have been reported to be related to disease progression. The objective of the current study was to evaluate these changes in prostatic tissue by means of immunohistochemistry and Western blot analysis.

METHODS

Immunohistochemical and Western blot analyses were performed in 20 normal samples, 35 samples of benign prostatic hyperplasia (BPH) and 27 samples from patients with prostate carcinoma (PC).

RESULTS

In normal prostate samples, immunoreactions to IL-1beta and IL-1RI were positive, whereas there were no immunoreactions observed to IL-1alpha, IL-1RII, or IL-1Ra. In BPH, in addition to immunoreactions to IL-1beta and IL-1RI, immunoreactions to IL-1alpha, IL-1RII, and IL-1Ra were observed in many samples. In samples of PC with low Gleason grade, most tumors had positive immunoreactions to IL-1alpha and IL-1RI. In samples of PC with high Gleason grade, immunoreactions were seen only to IL-1alpha, IL-1RI, and IL-1RII.

CONCLUSIONS

The current results suggested that high expression levels of IL-1alpha and IL1-RI in epithelial cells in BPH and PC samples were involved in cell proliferation and that the loss of immunoexpression of IL-1beta and IL-1Ra was a characteristic feature of PC compared with normal prostate samples and BPH. Because this loss is progressive up to a complete absence of immunoexpression in PC of high Gleason grade, the evaluation of IL-1beta and IL-1Ra in PC may be significant in assessing for malignancy.

[Cloning and expression of human IL-1R II gene]

AIM

To clone human IL-1R II cDNA and construct its recombinant retrovirus vector so as to explore its role in IL-1R II related diseases.

METHODS

Human IL-1R II cDNA was amplified by RT-PCR from peripheral blood mononuclear cells (PBMCs) and inserted into the vector PET22b to construct recombinant vector PET22b-IL-R II. The recombinant was transfected into E. coli BL21 and expressed under IPTG induction. Expressed products were detected by Western blot. In addition, human IL-1R-II cDNA was subcloned into retrovirus vector LZRSPBMN and transfected into 293 cells by calcium phosphate precipitation. IL-1R II expression was detected by immunohistochemical staining.

RESULTS

IL-1R II cDNA with 1,203 bp was amplified by RT-PCR from human PBMCs. The recombinant of this cDNA could be expressed in E. coli,which was confirmed by Western blot results. Immunohistochemistry detection showed IL-1R II protein was expressed in 293 cells.

CONCLUSION

Human IL-1R II gene was cloned successfully. PET22b-IL-1R II and LZR-IL-1R II were constructed and the recombinant protein IL-1R II was expressed in E.coli BL21. The results reported herein lay the foundation for further research on the role of IL-1R II in certain diseases.

Progression of radiographic changes in the temporomandibular joints of patients with rheumatoid arthritis in relation to inflammatory markers and mediators in the blood

The aim of this study was to investigate longitudinal radiographic changes in the temporomandibular joint (TMJ) with clinical involvement of rheumatoid arthritis (RA) and its relation to the blood level of inflammatory mediators and markers. Sixteen patients were investigated by computed tomography on two occasions 25-46 months apart. The radiographs were assessed independently for changes in presence of erosions, sclerosis, flattening, osteophytes, and subchondral pseudocysts. The serum (S) or plasma (P) concentrations of C-reactive protein (CRP), thrombocyte particle concentration, scrotonin (S-5-HT and P-5-HT), tumor necrosis factor alpha, interleukin-1 receptor antagonist, tumor necrosis factor soluble receptor type II, interleukin-1 soluble receptor type II (P-IL-1sRII) and interleukin 6 as well as the erythrocyte sedimentation rate (ESR) were measured. The radiographic status showed no consistent or significant change during the observation period, but the individual variation was considerable. The radiographic signs of erosion and sclerosis varied most. Regression of erosions was associated with high S-5-HT and P-IL-1sRII, while progression of erosions was associated with high P-5-HT. Regression of sclerosis was associated with an increase in P-5-HT and high ESR. Progression of flattening was associated with high CRP. In conclusion, this study indicates that the progression of radiographic changes that occurs in the TMJ of patients with well-controlled RA during a period of 25-46 months seems to be related to the blood levels of CRP, 5-HT, and IL-1sRII. However, only minor progression can be expected to occur, and with considerable individual variation.

Tuning of Innate Immunity and Polarized Responses by Decoy Receptors

After the identification of the interleukin (IL)-1 type II receptor as the prototype, decoy receptors have been identified for a number of members of the IL-1/IL-18, TNF, IL-10 and IL-13 receptor families. Moreover, the silent receptor D6 is a promiscuous decoy and scavenger receptor of inflammatory chemokines. The IL-1 decoy receptor is regulated by pro- and anti-inflammatory signals and its levels may serve as a readout of the activation of anti-inflammatory pathways, for instance by glucocorticoid hormones. Decoy receptors represent a strategy to tune inflammatory and polarized adaptive responses.

Homeostasis of the extracellular matrix of normal and osteoarthritic human articular cartilage chondrocytes in vitro

OBJECTIVE

In normal articular cartilage cells, the IGFRI/insulin-like growth factor 1 (IGF-1) autocrine pathway was shown to overrule the catabolic effects of the IL-1/IL-1RI pathway by up-regulation of the IL-1RII decoy receptor. The activity of the IGF-1/IGFR1 and IL-1/IL-1R pathways, and of the IL-1RII control mechanism in the synthesis and turnover of the extracellular matrix (ECM) by chondrocytes from normal and osteoarthritic (OA) articular cartilage was compared in order to identify possible therapeutic targets of this disease.

METHODS

Phenotypically stable human articular cartilage cells were obtained from normal and OA cartilage of the same knee showing focal OA. The cells were cultured in alginate beads over 1 week to re-establish the intracellular cytokine and growth factors, to reexpress the respective plasma membrane receptors and to reach equilibrium in accumulated cell-associated matrix (CAM) compounds. Following liberation of the cells from the alginate beads, the levels of cell-associated matrix (CAM) aggrecan, type II collagen and fibronectin, of intracellular IGF-1, IL-1alpha and beta and of their respective plasma membrane-bound receptors, IGFR1, IL-1RI and the decoy receptor IL-1RII, were assayed using flow cytometry.

RESULTS

Coordinated production and accumulation of CAM aggrecan and type II collagen under the effect of the IGFR1/IGF-1 autocrine pathway-as documented for chondrocytes from healthy controls-was absent when the chondrocytes had been obtained from OA joints. When compared with cells obtained from normal tissues, chondrocytes from fibrillated OA cartilage expressed significantly higher intracellular IGF-1 levels and plasma membrane-bound IGFR1. At the same time, significantly higher intracellular IL-1alpha and beta levels and upregulated plasma membrane-bound IL-1RI were observed. Plasma membrane-bound IL-1RII decoy receptor was downregulated in OA chondrocytes. The levels of CAM aggrecan, type II collagen and fibronectin were significantly reduced in the chondrocytes obtained from pathological tissue.

CONCLUSION

Paired analysis of normal and OA chondrocytes from the same knee joint has shown an enhanced capacity of chondrocytes from OA cartilage to produce ECM macromolecules. However, the same cells have increased catabolic signalling pathways. As a consequence of this increased IL-1 activity and the reduced amounts of IL-1RII decoy receptor, less of the produced ECM macromolecules may persist in the CAM of the OA chondrocytes.

Human colon carcinomas constitutively express and shed type II IL-1 receptor, an IL-1 antagonist

We reported earlier that rat intestinal epithelial cells respond to helminth infection, to NSAID injury, and to detachment in vitro with expression of the IL-1RII. Now we have sought to determine whether human colon carcinoma cell lines express, or may be induced to express, this potent IL-1 antagonist. Using RT-PCR, the T84 and HT-29 cell lines constitutively expressed mRNA for the membrane-bound, but not the secreted variant of the receptor. The protein was detectable by immunohistochemistry and was estimated to be 70 kDa by western blotting. TNF treatment of T84 cells led to slightly increased levels of IL-1RII mRNA and to significant increases in soluble protein detected in culture supernatants. Treating T84 cells with inhibitory anti-IL-1RII antibodies led to heightened responsiveness to IL-1, measured as IL-8 production. Expression of the IL-1RII by human epithelial cells has implications in terms of the IL-1 agonist versus antagonist balance in the diseased intestines.

[Significantly increased interleukin-1A and interleukin-1 soluble type II receptor levels in women with ovarian cancer]

OBJECTIVES

Recent studies indicate that interleukin-1 alpha (IL-1 alpha) is an autocrine growth factor for some ovarian cancer cells and suggest that IL-1 alpha plays an important role in the progression of this disease. However, soluble IL-1 receptors as IL-1 sRII, can modulate the effects of IL-1 alpha by acting as IL-1 alpha antagonists. The aim of our study was to compare serum IL-1 alpha and IL-1 sRII levels in patients with benign and malignant gynaecological tumours and in control.

MATERIALS AND METHODS

Pretreatment serum samples were obtained from 72 women with gynaecological tumors. This study included 37 patients with gynaecological cancers (21 with cervical cancer, 16 with ovarian cancer), and 35 women with benign gynaecological disorders (20 with ovarian tumour, 15 with uterine myoma). As a control group, sera were obtained from 20 healthy female volunteers. The levels of IL-1 alpha and IL-1 sRII were measured by ELISA (R&D Systems, Inc, Minneapolis, USA).

RESULTS

Serum IL-1 alpha and IL-1 sRII levels in women with ovarian cancers were significantly higher than those in cervical cancer, and in patients with benign disorders, and in healthy control (p < 0.0001).

CONCLUSIONS

Our results suggests that IL-1 alpha has a strong association with ovarian cancer.

The interleukin-1 family of cytokines and receptors in human breast cancer: implications for tumor progression

We have previously described the expression of interleukin cytokines (IL)-1alpha, IL-1beta, and IL-1 receptor antagonist (IL-1ra) in human breast cancer (HBC) tissue. Based on our previous studies, we hypothesize that the IL-1 family of cytokines, antagonists (IL-1ra) and receptors (IL-1RI and IL-1RII) are present within the human breast cancer (HBC) tumor microenvironment and that the IL-1 network of cytokines and receptors within the tumor microenvironment can control tumor cell subpopulation expression of other protumorigenic cytokines such as the angiogenic/growth factor, interleukin-8 (IL-8). To test this hypothesis we characterized the in vivo expression of the IL-1 network in HBC tissues and homogenates by immunohistochemistry (IHC) and ELISA. Additionally, we examined IL-1R expression in HBC cell lines in vitro and in a murine xenograft model by IHC. Finally, we determined the ability of IL-1 to induce IL-8 expression in in vitro using HBC cell lines. We observed that not only are the IL-1 cytokines present in HBC tissue and homogenates, but that IL-1Rs and IL-8 are also present in the HBC tumor microenvironment. Additionally, expression levels for some members of the IL-1/IL-8 network of cytokines correlated with the prognostic indicators, ER/PR. Using HBC cell lines, we observed that HBC cell lines express IL-1Rs in vitro and in the xenograft model. Furthermore, in vitro, HBC cell lines show a spectrum of responsiveness to IL-1 as measured by expression the proangiogenic/mitogenic cytokine IL-8. Our data clearly demonstrate the presence and distribution of IL-1 cytokines and receptors in HBC and suggests that the local expression of IL-1 results in the activation of a population of cells within the HBC tumor microenvironment. This activation of the IL-1/IL-1R cytokine family via autocrine and/or paracrine mechanisms leads to a cascade of secondary protumorigenic cytokines. These secondary signals induce the expression of numerous protumorigenic activities such as the expression of IL-8, and subsequently contribute to angiogenesis, tumor proliferation, and tumor invasion.

Gyrodactylus derjavini infection elicits IL-1beta expression in rainbow trout skin

Specific gene expression of the pro-inflammatory cytokine IL-1beta and the type II IL-1beta receptor (IL-1RII, 'decoy receptor') was studied in skin of rainbow trout Oncorhynchus mykiss (Walbaum, 1792) fry during infection with the ectoparasitic monogenean Gyrodactylus derjavini Mikailov, 1975. Cytokine expression was studied in both primary and secondary infections using a semi-quantitative RT-PCR technique. Generally, low levels of specific IL-1beta1, IL-1beta2 and IL-1RII gene transcription were found in uninfected hosts. In contrast, a clear induction of both IL-1beta isoforms could be observed during the initial phases of primary G. derjavini infections. A less obvious induction of IL-1beta expression was seen in secondary infections imposed just after recovery from the priming infection. However, challenge infections given one-month post full recovery of the primary infections did not elicit transcription levels above those seen in skin samples from uninfected hosts. Despite this, hosts carrying a secondary infection elicited a stronger response toward G. derjavini thus expelling parasites quicker than their nai;ve counterparts. When induced, indications of a more tight regulation of the IL-1beta1 isoform compared to IL-1beta2 could be observed. Increased expression of IL-1RII was seen later during the course of a primary infection and could be involved in the observed down regulation of IL-1, especially the beta1 isoform. The current study represents the first example of cytokine expression in fish induced by an ectoparasitic infection and indicates the importance of localised mucosal immune reactions in responses of fish towards gyrodactylids.

Inflammatory events are involved in acne lesion initiation

The earliest subclinical acne "lesion" is a microcomedone, of which hyperproliferation of the follicular epithelium is a characteristic feature. Inflammatory cells have been observed at the periphery of these "lesions". This study investigated whether inflammatory events occur pre or post hyperproliferative changes. Cellular, vascular, and proliferative markers were examined by immunohistochemical techniques on biopsies of clinically normal follicles from uninvolved skin and early inflamed lesions from acne patients. Control follicles were obtained from non-acne subjects. Follicles from uninvolved skin exhibited no microcomedonal features. Proliferation in the epithelium was comparable to controls and was significantly lower than in inflamed lesions. Numbers of CD3+, CD4+ T cells were elevated in the perifollicular and papillary dermis although levels were not equivalent to those in papules. The number of macrophages was also greatly increased and similar to those in papules. There were no changes in blood vessel numbers or vascular intercellular adhesion molecule 1 expression but E-selectin expression was increased to levels found in papules and vascular adhesion molecule 1 levels were upregulated. Levels of the pro-inflammatory cytokine interleukin-1 were also upregulated perifollicularly. Moreover, aberrant integrin expression was demonstrated in the epidermis around these uninvolved follicles and inflamed lesions whereas the basement membrane was still intact. These results provide novel evidence for vascular endothelial cell activation and involvement of inflammatory responses in the very earliest stages of acne lesion development.

Relative cytokine and cytokine inhibitor production by mononuclear cells and neutrophils

Mononuclear cells represent the major source of cytokines in blood; however, it has been postulated that neutrophils may produce and/or release modest amounts of cytokines. In this study, we compared the production of cytokines and cytokine inhibitors in lipopolysaccharide (LPS)-stimulated whole blood, peripheral blood mononuclear cells (PBMCs), and neutrophils (PMNs) separated by density gradient centrifugation. Contamination of PBMCs in the isolated PMNs was less than 0.1% as determined by morphological analysis and flow cytometry. LPS (50 ng/mL) induced a strong increase of the proinflammatory cytokines tumor necrosis factor, interleukin (IL)-1beta, IL-8, and IL-6 in whole blood. In the isolated cell preparations, proinflammatory cytokine production was significantly greater in the PBMCs compared with the PMNs. On a per cell basis, PMNs produced less than 1.5% of these cytokines compared with PBMCs. For cytokine inhibitors, TNF-soluble receptor type II and IL-1 receptor antagonist were increased by LPS stimulation in whole blood, PBMCs, and PMNs. On a per cell basis, LPS-induced TNF-soluble receptor type II and IL-1 receptor antagonist production by PMNs was 9.8% and 15.4% of those of PBMCs, respectively. These data show that a highly purified population of PMNs makes a relatively minor to nonexistent contribution to the production of proinflammatory cytokines.

IL-1 beta scavenging by the type II IL-1 decoy receptor in human neutrophils

IL-1 elicits its cellular effects by binding a heterodimeric receptor consisting of IL-1RI and the accessory protein, IL-1RAcPr. In addition, it binds to IL-1RII, which lacking signaling function has been ascribed a decoy role. The fate of the ligand following interaction with the decoy receptor was examined in human polymorphonuclear cells (PMN), which express predominantly (>90%) IL-1RII. Incubation of PMN with IL-1beta results in a rapid decrease in cell surface-associated ligand accompanied by a concomitant increase in internalized IL-1 with 50-60% of IL-1beta located intracellularly within 1 h at 37 degrees C. The use of blocking Abs revealed that IL-1 internalization is mediated exclusively by the decoy receptor. The results of inhibitor analysis demonstrate that internalization requires ATP synthesis and involves clathrin-mediated endocytosis. Following removal of the ligand, the receptor was rapidly re-expressed on the cell surface. Cyclohexamide, a protein synthesis inhibitor, had no effect upon the process, suggesting that the re-expressed receptor was recycled. In addition, human keratinocytes stably transfected with IL-1RII (HaCAT 811) also internalized the IL-1RII with 43% cell surface receptor internalized after 90 min. Immunofluorescence microscopy revealed colocalization of the internalized receptor with wheat germ agglutinin-labeled internalized glycoproteins and early endosome Ag-1, a protein associated with the early endosome compartments, indicative of cellular uptake of IL-1RII by endocytosis. In contrast, little or no internalization was observed in other cells of immune origin. These results suggest that the decoy receptor IL-1RII can act as a scavenger of IL-1, representing a novel autoregulatory mechanism of the IL-1 system.

Interleukin-1 (IL-1) system gene expression in granulosa cells: kinetics during terminal preovulatory follicle maturation in the mare

BACKGROUND

A growing body of evidences suggests that the ovary is a site of inflammatory reactions, and thus, ovarian cells could represent sources and targets of the interleukin-1 (IL-1) system. The purpose of this study was to examine the IL-1 system gene expressions in equine granulosa cells, and to study the IL-1beta content in follicular fluid during the follicle maturation. For this purpose, granulosa cells and follicular fluids were collected from the largest follicle at the early dominance stage (diameter 24 +/- 3 mm) or during the preovulatory maturation phase, at T0 h, T6 h, T12 h, T24 h and T34 h after induction of ovulation. Cells were analysed by RT-PCR and follicular fluids were studied by gel electrophoresis and immunoblotting.

RESULTS

We demonstrated that interleukin-1beta (IL-1beta), interleukin-1 receptor 2 (IL-1R2) and interleukin-1 receptor antagonist (IL-1RA) genes are expressed in equine granulosa cells. We observed that the IL-1beta and IL-1RA mRNA content changed in granulosa cells during the terminal follicular maturation whereas IL-1R2 mRNA did not vary. In follicular fluid, IL-1beta content fluctuated few hours after induction of ovulation.

CONCLUSIONS

The expression of IL-1beta gene in granulosa cells and the follicular fluid IL-1beta content seem to be regulated by gonadotropins suggesting that IL-1beta could be an intermediate paracrine factor involved in ovulation.

IL-1beta-dependent neurological effects of the whole cell pertussis vaccine: a role for IL-1-associated signalling components in vaccine reactogenicity

Immunization with the whole cell pertussis vaccine (Pw), but not the acellular pertussis vaccine (Pa), is associated with a number of neurological side effects. Previously, we have demonstrated a role for interleukin-1beta (IL-1beta) in Pw reactogenicity. Here we report that parenteral Pw administration resulted in a concomitant increase IL-1 type I receptor (IL-1RI) mRNA and a decrease in IL-1 type II receptor (IL-1RII) mRNA expression in the murine hypothalamus. These Pw-induced changes were accompanied by an increase in caspase-1 and interleukin-1beta (IL-1beta), and were associated with increased activity of the stress-activated kinase, p38. In contrast, immunization with Pa failed to activate pro-inflammatory IL-1 responses but resulted in increased IL-1 receptor antagonist (IL-1ra) production. These results suggest that the neurological effects of Pw are associated with central activation of IL-1beta and IL-1-associated signalling components.

The soluble form of IL-1 receptor accessory protein enhances the ability of soluble type II IL-1 receptor to inhibit IL-1 action

Regulation of the activity of the proinflammatory cytokine IL-1 is complex, involving transcriptional and translational control, precursor processing, a receptor antagonist (IL-1ra), and a decoy receptor. Here we report that the soluble form of the IL-1 receptor accessory protein (AcP) increases the affinity of binding of human IL-1alpha and IL-1beta to the soluble human type II IL-1 receptor by approximately 100-fold, while leaving unaltered the low binding affinity of IL-1ra. Soluble AcP is present in normal human serum at an average concentration greater than 300 ng/ml. These findings suggest that the soluble form of IL-1R AcP contributes to the antagonism of IL-1 action by the type II decoy receptor, adding another layer of complexity to the regulation of IL-1 action.

A single amino acid difference between human and monkey interleukin (IL)-1beta dictates effective binding to soluble type II IL-1 receptor

Soluble type II interleukin (IL)-1 receptor (sIL1R-II) binds human IL-1beta with high affinity and neutralizes its activity. Recombinant sIL1R-II is considered a potentially useful anti-IL-1 therapeutic, and preclinical studies have been undertaken with this molecule in primates. To better understand the cytokine-receptor interactions occurring in this nonhuman context, monkey IL-1 and IL1R-II were cloned, and their binding abilities were examined in vitro. IL-1beta from cynomolgus monkey was capable of binding and activating the human type I IL-1 receptor. However, unlike human IL-1beta, it was unable to effectively bind and become neutralized by sIL1R-II. Human and cynomolgus IL-1beta proteins are 96% identical, differing by only six amino acids. Structural and mutational analysis revealed that the unique sIL1R-II binding ability of human IL-1beta is due to a single amino acid difference compared with monkey IL-1beta.

Effect of IL-18 on IL-1beta and sIL-1RII production by human neutrophils

In the present study we investigated the effect of interleukin 18 (IL-18) on the production of IL-1beta and soluble IL-1 receptor II (sIL-1RII) by human neutrophils. The results obtained indicate that recombinant human IL-18 (rhIL-18) induces IL-1beta and, to a lesser extent, sIL-1RII production by human neutrophil isolated from peripheral blood. However, this effect was less important than lipopolysaccharide (LPS) stimulation. Additionally, our observations suggest that IL-18 can induce priming of neutrophils for IL-1beta and, to a lesser extent, sIL-IRII production by LPS-stimulated cells. The ability of IL-18 to serve as an effective modulator for IL-1beta and its regulatory protein may have significance in the inflammatory and immune reactions mediated by IL-1beta.

Expression of interleukin-1 receptors and their role in interleukin-1 actions in murine microglial cells

Interleukin (IL)-1 is an important mediator of acute brain injury and inflammation, and has been implicated in chronic neurodegeneration. The main source of IL-1 in the CNS is microglial cells, which have also been suggested as targets for its action. However, no data exist demonstrating expression of IL-1 receptors [IL-1 type-I receptor (IL-1RI), IL-1 type-II receptor (IL-1RII) and IL-1 receptor accessory protein (IL-1RAcP)] on microglia. In the present study we investigated whether microglia express IL-1 receptors and whether they present target or modulatory properties for IL-1 actions. RT-PCR analysis demonstrated lower expression of IL-1RI and higher expression of IL-1RII mRNAs in mouse microglial cultures compared with mixed glial or pure astrocyte cultures. Bacterial lipopolysaccharide (LPS) caused increased expression of IL-1RI, IL-1RII and IL-1RAcP mRNAs, induced the release of IL-1beta, IL-6 and prostaglandin-E2 (PGE2), and activated nuclear factor kappaB (NF-kappaB) and the mitogen-activated protein kinases (MAPKs) p38, and extracellular signal-regulated protein kinase (ERK1/2), but not c-Jun N-terminal kinase (JNK) in microglial cultures. In comparison, IL-1beta induced the release of PGE2, IL-6 and activated NF-kappaB, p38, JNK and ERK1/2 in mixed glial cultures, but failed to induce any of these responses in microglial cell cultures. IL-1beta also failed to affect LPS-primed microglial cells. Interestingly, a neutralizing antibody to IL-1RII significantly increased the concentration of IL-1beta in the medium of LPS-treated microglia and exacerbated the IL-1beta-induced IL-6 release in mixed glia, providing the first evidence that microglial IL-1RII regulates IL-1beta actions by binding excess levels of this cytokine during brain inflammation.

White matter lesions and soluble interleukin-1 receptor type II in CSF from demented and non-demented subjects

White matter lesions (WMLs) in the brain is a common, unspecific finding on magnetic resonance imaging appearing both in the healthy elderly as well as in a number of different diseases including dementia disorders. However, the pathophysiological and clinical significance of WMLs in dementia disorders is still unknown. In this study, we investigated the possibility of their origin being inflammatory by studying the correlation between WMLs and cerebrospinal fluid (CSF) levels of the proinflammatory cytokine soluble interleukin-1 receptor type II (sIL-1RII). The sIL-1RII is a member of the IL-1 family, and has been found to be elevated in CSF from Alzheimer's disease (AD) patients. In the present study, two groups of patients complaining of memory disturbances with little or extensive WMLs respectively, were examined, as well as healthy subjects. In accordance with other reports, WML scores (total, periventricular as well as deep lesions) were positively correlated with age but not mini mental state examination (MMSE) scores, and were significantly higher in patients with a dementia diagnosis as compared to non-demented subjects. There were no differences in sIL-1RII levels in CSF regardless of amount of total, periventricular or deep WMLs, nor were there any differences between demented and non-demented subjects. In conclusion, sIL-1RII levels in CSF are not correlated to magnetic resonance imaging WMLs in patients with dementia disorders or in healthy subjects.

Inhibition of interleukin-1 but not tumor necrosis factor suppresses neovascularization in rat models of corneal angiogenesis and adjuvant arthritis

OBJECTIVE

To assess the capacities of the cytokine inhibitors interleukin-1 receptor antagonist (IL-1Ra; anakinra) and PEGylated soluble tumor necrosis factor receptor I (PEG sTNFRI; pegsunercept) to suppress neovascularization.

METHODS

A corneal angiogenesis assay was performed by implanting nylon discs impregnated with an angiogenic stimulator (basic fibroblast growth factor or vascular endothelial growth factor) into one cornea of female Sprague-Dawley rats. Animals were treated with IL-1Ra or PEG sTNFRI for 7 days, after which new vessels were quantified. In a parallel study, male Lewis rats with mycobacteria-induced adjuvant-induced arthritis were treated with IL-1Ra or PEG sTNFRI for 7 days beginning at disease onset, after which scores for inflammation and bone erosion as well as capillary counts were acquired from sections of arthritic hind paws.

RESULTS

Treatment with IL-1Ra yielded a dose-dependent reduction in growth factor-induced corneal angiogenesis, while PEG sTNFRI did not. IL-1Ra, but not PEG sTNFRI, significantly reduced the number of capillaries in arthritic paws, even though both anticytokines reduced inflammation and bone erosion to a similar degree.

CONCLUSION

These data support a major role for IL-1, but not TNFalpha, in angiogenesis and suggest that an additional antiarthritic mechanism afforded by IL-1 inhibitors, but not anti-TNF agents, is the suppression of the angiogenic component of pannus.

IL-1 beta potentiates heat-activated currents in rat sensory neurons: involvement of IL-1RI, tyrosine kinase, and protein kinase C

Interleukin 1 beta (IL-1 beta) is a proinflammatory cytokine that maintains thermal hyperalgesia and facilitates the release of calcitonin gene-related peptide from rat cutaneous nociceptors in vivo and in vitro. Brief applications of IL-1 beta to nociceptive neurons yielded a potentiation of heat-activated inward currents (Iheat) and a shift of activation threshold toward lower temperature without altering intracellular calcium levels. The IL-1 beta-induced heat sensitization was not dependent on G-protein-coupled receptors but was mediated by activation of protein kinases. The nonspecific protein kinase inhibitor staurosporine, the specific protein kinase C inhibitor bisindolylmaleimide BIM1, and the protein tyrosine kinase inhibitor genistein reduced the sensitizing effect of IL-1 beta whereas negative controls were ineffective. RT-PCR and in situ hybridization revealed IL-1RI but not RII expression in neurons rather than surrounding satellite cells in rat dorsal root ganglia. IL-1 beta acts on sensory neurons to increase their susceptibility for noxious heat via an IL-1RI/PTK/PKC-dependent mechanism.

Soluble interleukin-1 receptor type II blocks monocyte chemotactic protein-1 secretion by U937 cells in response to peripheral blood serum of women with endometriosis

OBJECTIVE

To assess the ability of peripheral blood serum from women with endometriosis to induce monocyte chemotactic protein-1 (MCP-1) secretion by monocytes and the putative role of the interleukin-1 (IL-1) system in endometriosis-associated monocyte activation.

DESIGN

Cultures of U937 monocytic cells exposed to serum from normal women (control group) or women with endometriosis.

SETTING

Gynecology clinic and human reproduction research laboratory.

PATIENT(S)

Seventy-nine women with endometriosis and 38 control women with no evidence of endometriosis at laparoscopy.

INTERVENTION(S)

Peripheral blood obtained a few days before laparoscopy.

MAIN OUTCOME MEASURE(S)

MCP-1 secretion in the culture medium and serum concentrations of soluble IL-1 receptor type II (sIL-1RII), IL-1beta, and IL-1alpha by ELISA or by enzyme immunometric assay.

RESULT(S)

Serum concentrations of sIL-1RII were significantly lower in women with stage I-II endometriosis than in control women, whereas serum concentrations of IL-1beta and IL-1alpha were comparable between the two groups. The serum of women with endometriosis induced higher secretion of MCP-1 by U937 cells than that of control women, particularly in the initial stages of endometriosis (stages I-II), and recombinant IL-1RII (rIL-1RII) significantly blocked that secretion.

CONCLUSION(S)

These findings point toward a deficiency in the mechanisms involved in the down-regulation of IL-1 actions at the systemic level and reveal sIL-1RII as a key factor involved in that process.

Heat stress and/or endotoxin effects on cytokine expression by human whole blood

Immune system cytokines induce vascular shock. Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and bacterial endotoxin (E) circulate in human heatstroke to suggest that E release from a heat-damaged gut may stimulate cytokines that contribute to hypovolemia. However, immune activation by heat-induced tissue necrosis might stimulate cytokine generation in the absence of E. To evaluate this potential and heat stress effects on the anti-inflammatory cytokines, IL-1 receptor antagonist (IL-1ra) and IL-1 soluble receptor II (IL-1srII), a human whole blood (HWB) model was employed in which the presence or absence of E could be controlled. Using thermoelectric technology to regulate the HWB heat exposures, the temperature modulations of lethal heatstroke were precisely replicated (maximum temperature = 42.4 degrees C +/- 0.04 degrees C; thermal area = 52.3 degrees C +/- 1.5 degrees C per min). Cytokine and mRNA measurements employed enzyme-linked immunosorbant-based assay systems. Significant elevations in TNF-alpha, IL-1beta, interleukin 6 (IL-6), and IL-1ra resulted when HWB was exposed to E concentrations (10 ng/ml) reported to circulate in heatstroke. While E-stimulated IL-1ra was significantly decreased by the presence of prior heat stress (PPHS), E-stimulated IL-1beta, TNF-alpha, and IL-6 were not significantly altered by PPHS, but tended to be elevated. IL-1srII expression was unchanged by PPHS and/or E. PPHS in the absence of E did not induce cytokine responses, nor were there elevations in TNF-alpha or IL-1beta mRNA. Thus, some factor normally absent under in vitro conditions, like endotoxin, was required to provoke HWB cytokine expressions and the heat stress and E conditions that characterize heatstroke affected HWB cytokine metabolism to favor a proinflammatory environment.

Functional genomic analysis of type II IL-1beta decoy receptor: potential for gene therapy in human arthritis and inflammation

Gene expression arrays show that human epithelial cells and human arthritis-affected cartilage lack detectable amounts of mRNA for IL-1 antagonizing molecules: IL-1Ra and IL-1RII, but constitutively express IL-1. Functional genomic analysis was performed by reconstituting human IL-1RII expression in various IL-1RII-deficient cell types to examine its antagonist role using gene therapy approaches. Adenovirus-expressing IL-1RII when transduced into human and bovine chondrocytes, human and rabbit synovial cells, human epithelial cells, and rodent fibroblasts expressed membrane IL-1RII and spontaneously released functional soluble IL-1RII. The IL-1RII(+) (but not IL-1RII(-)) cells were resistant to IL-1beta-induced, NO, PGE(2), IL-6, and IL-8 production or decreased proteoglycan synthesis. IL-1RII inhibited the function of IL-1 in chondrocytes and IL-1- and TNF-alpha-induced inflammatory mediators in human synovial and epithelial cells. IL-1RII(+) chondrocytes were more resistant to induction of NO and PGE(2) by IL-1beta compared with IL-1RII(-) cells incubated with a 10-fold (weight) excess of soluble type II IL-1R (sIL-1RII) protein. In cocultures, IL-1RII(+) synovial cells released sIL-1RII, which in a paracrine fashion protected chondrocytes from the effects of IL-1beta. Furthermore, IL-1RII(+) (but not IL-1RII(-)) chondrocytes when transplanted onto human osteoarthritis-affected cartilage in vitro, which showed spontaneous release of sIL-1RII for 20 days, inhibited the spontaneous production of NO and PGE(2) in cartilage in ex vivo. In summary, reconstitution of IL-1RII in IL-1RII(-) cells using gene therapy approaches significantly protects cells against the autocrine and paracrine effects of IL-1 at the signaling and transcriptional levels.

Abnormal interleukin-1 receptor type II gene expression in the endometrium of women with endometriosis

Interleukin 1 (IL-1) is a major proinflammatory cytokine that is believed to play a central role in the pathophysiology of endometriosis. The IL-1 receptor type II (IL-1RII) is known to bind to IL-1 and to inhibit its biological effects. In our previous studies, we showed that human endometrium expresses IL-1RII, and we observed reduced expression of the protein in women with endometriosis. The aim of this study was to investigate IL-1RII mRNA in the endometrial tissue of normal women (n = 26) and of patients with various degrees of endometriosis (n = 53). In situ hybridization showed that IL-1RII mRNA expression was significantly decreased in endometriosis, particularly during the early stages of the disease (stages I and II). This was quite obvious in both glandular and stromal cells, and it was corroborated by reverse transcription-polymerase chain reaction analysis of IL-1RII mRNA in the endometrial tissue of women with (n = 10) and without (n = 8) endometriosis. The reduced levels of IL-1RII mRNA in the endometrium of women suffering from endometriosis reveals a profound defect in IL-1RII gene expression and, consequently, a reduced capability of endometrial tissue to down-regulate IL-1 activity. Defective IL-1RII gene expression during the early stages of endometriosis (stages I and II) may contribute to the etiology of the disease.

Glucosamine modulates IL-1-induced activation of rat chondrocytes at a receptor level, and by inhibiting the NF-kappa B pathway

We recently reported that glucosamine reversed the decrease in proteoglycan synthesis and in UDP-glucuronosyltransferase I mRNA expression induced by interleukin-1 beta (IL-1 beta) [Arthritis Rheum. 44 (2001) 351-360]. In the present work, we show that glucosamine does not exert the same effects when chondrocytes were stimulated with reactive oxygen species (ROS). In order to better understand its mechanism of action, we determined if glucosamine could prevent the binding of IL-1 beta to its cellular receptors or could interfere with its signaling pathway at a post-receptor level. Addition of glucosamine to rat chondrocytes treated with IL-1 beta or with ROS decreased the activation of the nuclear factor kappa B, but not the activator protein-1. After treatment with IL-1 beta, glucosamine increased the expression of mRNA encoding the type II IL-1 beta receptor. These results emphasize the potential role of two regulating proteins of the IL-1 beta signaling pathway that could account for the beneficial effect of glucosamine in osteoarthritis.