Interleukin-1 Family Members Research Articles

CNS-specific Therapy for Ongoing EAE by Silencing IL-17 Pathway in Astrocytes

The interleukin-17 (IL-17) cytokine family is crucial to the progression of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). It has been shown in a neuroectoderm-specific knockout study that astrocyte-restricted ablation of Act1, a key and common transcription factor for signals mediated by IL-17 family members (IL-17A, IL-17F, and IL-17C), ameliorates EAE. However, the effect of Act1 deficiency in astrocytes on ongoing disease, which is of clinical relevance for MS therapy, has not been investigated. Here we report that intracerebroventricular (i.c.v.) injection of a novel lentiviral vector (shAct1) to knockdown Act1 expression in astrocytes effectively inhibited disease progression at EAE induction, clinical onset, and peak of disease (ongoing phases), with significantly reduced numbers of infiltrating inflammatory cells and percentage of Th17 cells in the central nervous system (CNS). This was mainly due to the suppressed expression of Th17-related chemokines in astrocytes, while neurotrophic factors in the CNS and immune responses in the periphery were not affected. These results demonstrate that blocking the IL-17 pathways in astrocytes is a promising therapeutic approach for MS in a CNS-specific manner, which does not interfere with systemic immune responses, a major concern in conventional MS therapy.

Assessment of Echocardiography and Biomarkers for the Extended Prediction of Cardiotoxicity in Patients Treated With Anthracyclines, Taxanes, and Trastuzumab

Because cancer patients survive longer, the impact of cardiotoxicity associated with the use of cancer treatments escalates. The present study investigates whether early alterations of myocardial strain and blood biomarkers predict incident cardiotoxicity in patients with breast cancer during treatment with anthracyclines, taxanes, and trastuzumab. Eighty-one women with newly diagnosed human epidermal growth factor receptor 2-positive breast cancer, treated with anthracyclines followed by taxanes and trastuzumab were enrolled to be evaluated every 3 months during their cancer therapy (total of 15 months) using echocardiograms and blood samples. Left ventricular ejection fraction, peak systolic longitudinal, radial, and circumferential myocardial strain were calculated. Ultrasensitive troponin I, N-terminal pro-B-type natriuretic peptide, and the interleukin family member (ST2) were also measured. Left ventricular ejection fraction decreased (64 ± 5% to 59 ± 6%; P<0.0001) over 15 months. Twenty-six patients (32%, [22%-43%]) developed cardiotoxicity as defined by the Cardiac Review and Evaluation Committee Reviewing Trastuzumab; of these patients, 5 (6%, [2%-14%]) had symptoms of heart failure. Peak systolic longitudinal myocardial strain and ultrasensitive troponin I measured at the completion of anthracyclines treatment predicted the subsequent development of cardiotoxicity; no significant associations were observed for left ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide, and ST2. Longitudinal strain was <19% in all patients who later developed heart failure. In patients with breast cancer treated with anthracyclines, taxanes, and trastuzumab, systolic longitudinal myocardial strain and ultrasensitive troponin I measured at the completion of anthracyclines therapy are useful in the prediction of subsequent cardiotoxicity and may help guide treatment to avoid cardiac side-effects.

Cytokine-Like Factor 1 Gene Expression Is Enriched in Idiopathic Pulmonary Fibrosis and Drives the Accumulation of CD4+ T Cells in Murine Lungs: Evidence for an Antifibrotic Role in Bleomycin Injury

Idiopathic pulmonary fibrosis (IPF) is a progressive and typically fatal lung disease. To gain insight into the pathogenesis of IPF, we reanalyzed our previously published gene expression data profiling IPF lungs. Cytokine receptor-like factor 1 (CRLF1) was among the most highly up-regulated genes in IPF lungs, compared with normal controls. The protein product (CLF-1) and its partner, cardiotrophin-like cytokine (CLC), function as members of the interleukin 6 (IL-6) family of cytokines. Because of earlier work implicating IL-6 family members in IPF pathogenesis, we tested whether CLF-1 expression contributes to inflammation in experimental pulmonary fibrosis. In IPF, we detected CLF-1 expression in both type II alveolar epithelial cells and macrophages. We found that the receptor for CLF-1/CLC signaling, ciliary neurotrophic factor receptor (CNTFR), was expressed only in type II alveolar epithelial cells. Administration of CLF-1/CLC to both uninjured and bleomycin-injured mice led to the pulmonary accumulation of CD4(+) T cells. We also found that CLF-1/CLC administration increased inflammation but decreased pulmonary fibrosis. CLF-1/CLC leads to significantly enriched expression of T-cell-derived chemokines and cytokines, including the antifibrotic cytokine interferon-γ. We propose that, in IPF, CLF-1 is a selective stimulus of type II alveolar epithelial cells and may potentially drive an antifibrotic response by augmenting both T-helper-1-driven and T-regulatory-cell-driven inflammatory responses in the lung.

Novel regulation of TNFα-induced-IL-18 bioactivity in rheumatoid arthritis synovial fibroblasts by reducing caspase-1 Via JAK2 inhibition

Background/purposeRheumatoid arthritis (RA) is the most common inflammatory chronic joint disorder. Interleukin-1 (IL-1) family members play a key part in the pathogenesis of RA. Among the IL-1 cytokine family members,...

Birth control vaccine targeting leukemia inhibitory factor

The population explosion and unintended pregnancies resulting in elective abortions continue to impose major public health issues. This calls for a better method of contraception. Immunocontraception has been proposed as a valuable alternative that can fulfill most, if not all, of the properties of an ideal contraceptive. There are several targets that are being explored for contraceptive vaccine development. Leukemia inhibitory factor (LIF), a member of interleukin-6 family, is required for embryo development and successful blastocyst implantation in several mammalian species. The present study was conducted to examine if LIF can be a target for the development of a birth control vaccine. Three sequences from LIF and two sequences from LIF-receptor (LIF-R) that span the regions involved in ligand-receptor binding were delineated, and peptides were synthesized based upon these sequences. Antibodies raised against these five peptides reduced LIF bioactivity in an in vitro culture assay using BA/F3 mLIF-R-mpg130 cells. Vaccines were prepared by conjugating these peptides to various carrier proteins. Immunization of female mice with these peptide vaccines induced a long-lasting, circulating as well as local antibody response in various parts of the genital tract, and resulted in a significant (P ≤ 0.05) inhibition in fertility in all the three trials; the LIF-R peptide vaccines proved to be a better vaccine target. The data indicate that LIF/LIF-R is an excellent target for the development of a birth control vaccine. This is the first study, to our knowledge, that examined LIF/LIF-R as a target for immunocontraception. The findings of this study can be easily translated to humans since LIF/LIF-R is also important for implantation and pregnancy in women.

PS1-007. The RNA-binding protein tristetraprolin controls the balance between Interleukin-12 family members

PS1-007. The RNA-binding protein tristetraprolin controls the balance between Interleukin-12 family members

Tissue and circulating expression of IL-1 family members following heat stroke

Interleukin-1 (IL-1) is thought to have a significant role in the pathophysiology of heat stroke (HS), although little is known regarding the actions or expression patterns of the IL-1 family. This study tested the hypotheses that following HS IL-1 family gene expression is dynamic, while loss of IL-1 signaling enhances recovery. IL-1 family expression was determined in plasma, spleen, and liver from C57BL/6J mice (n=24 control, n=20 HS) at maximum core temperature (Tc,Max), hypothermia, and 24 h post-HS (24 h). Soluble IL-1 receptor subtype I (sIL-1RI) protein expression peaked at 24 h (14,659.01±2,016.28 pg/ml, P<0.05), while sIL-1RII peaked at hypothermia (19,099.30±1,177.07 pg/ml). IL-1α gene expression in the spleen (ninefold) and liver (fourfold) along with IL-1RI (threefold spleen and fivefold liver) were maximal at hypothermia. Spleen IL-1β gene expression peaked at Tc,Max (fourfold) but at hypothermia (fourfold) in liver. Gene expression of the IL-1 family member IL-18 peaked (2.5-fold) at Tc,Max but was similar at all other time points. Subsequent studies revealed that despite accruing a greater heating area (298±16 vs. 247±13°C·min, P<0.05), IL-1RI knockout (KO) mice (n=14) showed an attenuated hypothermia depth (28.5±0.2 vs. 27.3±0.5°C, P<0.05) and duration (675±82 vs. 1,283±390 min, P<0.05) with a higher 24 h Tc (36.9 vs. 34.1°C, P<0.05) compared with C57BL/6J mice (n=8). The current results demonstrate that following HS IL-1 family gene expression is altered and IL-1RI KO mice display Tc responses consistent with a more rapid recovery.

Novel cytokine signaling pathways in inflammatory bowel disease: insight into the dichotomous functions of IL-33 during chronic intestinal inflammation

In 2010, four independent groups almost simultaneously reported the association of the novel interleukin-1 (IL-1) family member, IL-33, with inflammatory bowel disease (IBD). The findings were remarkably consistent and demonstrated that IL-33 is markedly upregulated in, and specific to, ulcerative colitis (UC). In addition, although a variety of gut-associated immune cell subsets express IL-33, the primary source appears to be the intestinal epithelium. IL-33's receptor, ST2, a formerly orphaned IL-1 receptor-related protein, was also found to be increased in UC patients, although the cellular source of ST2 appears to be somewhat more ambiguous. In fact, emerging evidence indicates that the IL-33/ST2 axis plays a critical role in several other chronic inflammatory and immune disorders. In the gut, IL-33 has been shown to be important in the clearance of intestinal parasites, and inducing epithelial cell hyperplasia, mucus production and mucosal eosinophilic infiltration. However, despite the established trend of increased IL-33 and ST2 expression during IBD, specifically UC, the precise pathophysiologic relevance of these findings has yet to be determined. Interestingly, IL-33 has the ability to potentiate pathogenic Th2 and Th17 responses in gut-associated lymphoid tissues, while also promoting healing of damaged mucosa following inflammatory insults. Indeed, further mechanistic studies are warranted to confirm the possible dichotomous functions of IL-33 during chronic intestinal inflammation and better define its precise role in the pathogenesis of IBD. Herein, we discuss what is currently known about IL-33/ST2 in the gut and speculate as to the potential role of the IL-33/ST2 system in IBD.

Antagonistic RNA aptamer specific to a heterodimeric form of human interleukin-17A/F

Interleukin-17 (IL-17) is a pro-inflammatory cytokine produced primarily by a subset of CD4 + T cells, called Th17 cells, that is involved in host defense, inflammation and autoimmune disorders. The two most structurally related IL-17 family members, IL-17A and IL-17F, form homodimeric (IL-17A/A, IL-17F/F) and heterodimeric (IL-17A/F) complexes. Although the biological significance of IL-17A and IL-17F have been investigated using respective antibodies or gene knockout mice, the functional study of IL-17A/F heterodimeric form has been hampered by the lack of an inhibitory tool specific to IL-17A/F. In this study, we aimed to develop an RNA aptamer that specifically inhibits IL-17A/F. Aptamers are short single-stranded nucleic acid sequences that are selected in vitro based on their high affinity to a target molecule. One selected aptamer against human IL-17A/F, AptAF42, was isolated by repeated cycles of selection and counterselection against heterodimeric and homodimeric complexes, respectively. Thus, AptAF42 bound IL-17A/F but not IL-17A/A or IL-17F/F. The optimized derivative, AptAF42dope1, blocked the binding of IL-17A/F, but not of IL-17A/A or IL-17F/F, to the IL-17 receptor in the surface plasmon resonance assay in vitro. Consistently, AptAF42dope1 blocked cytokine GRO-α production induced by IL-17A/F, but not by IL-17A/A or IL-17F/F, in human cells. An RNA footprinting assay using ribonucleases against AptAF42dope1 in the presence or absence of IL-17A/F revealed that part of the predicted secondary structure fluctuates between alternate forms and that AptAF42dope1 is globally protected from ribonuclease cleavage by IL-17A/F. These results suggest that the selected aptamer recognizes a global conformation specified by the heterodimeric surface of IL-17A/F.

Abstract 1580: Molecular mechanisms of OSM-induced VEGF in breast cancer

Abstract Oncostatin M (OSM) is an interleukin-6 (IL-6) family cytokine that has been shown to induce expression of vascular endothelial growth factor (VEGF) in astroglioma and in hepatocellular and breast carcinoma. It is also known to induce VEGF in non-cancerous cells such as cardiac myocytes, hepatocytes, and smooth muscle cells. Under hypoxic conditions, VEGF expression is known to be dependent on the transcription factor hypoxia-inducible factor 1 alpha (HIF1α). Our current studies were designed to determine whether VEGF expression induced by OSM and other IL-6 family members, including IL-6 and leukemia inhibitory factor (LIF), is likewise dependent on HIF1α in human breast cancer cells. To analyze VEGF expression levels, MDA-MB-231 and T47D human breast cancer cells were cultured in the presence or absence of OSM, IL-6, and LIF, with or without a HIF1α siRNA, for 12 to 72 hrs. All three cytokines significantly induced HIF1α expression by Western blot analysis at each time point in both MDA-MD-231 and T47D cells. Conditioned media from these experiments was also analyzed using ELISA to determine HIF1α-induced VEGF expression. Treatment with OSM resulted in a two- to three-fold induction of secreted VEGF, while treatment with IL-6 and LIF showed no significant induction. In addition, OSM-induced VEGF expression was independent of HIF1α in MDA-MB-231 cells. This was indicated by unchanged secreted VEGF levels despite the reduction of HIF1α expression in siRNA treated groups. In T47D cells however, HIF1α siRNA-treatment for 72 hrs reduced VEGF levels by 40% suggesting that OSM-induced HIF1α may be partially responsible for VEGF expression in this cell line. To summarize, it is important to note that IL-6 and LIF did not induce VEGF expression in two commonly used human breast cancer cell lines, MDA-MB-231 and T47D. Furthermore, OSM-induced VEGF was not dependent on HIF1α in MDA-MB-231 cells, suggesting regulation of VEGF by an alternative molecular mechanism. Investigations are in progress to better understand mechanisms utilized by breast cancer cells for OSM-induced VEGF expression. Future results could lead to the potential design of OSM-targeted therapeutics. Funded by NIH R15CA137510, ACS RSG-09-276-01-CSM, Susan G. Komen for the Cure KG100513, and NIH/NCRR P20RR016454. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1580. doi:10.1158/1538-7445.AM2011-1580

Adipose and Liver Expression of Interleukin (IL)-1 Family Members in Morbid Obesity and Effects of Weight Loss

Morbid obesity is associated with a state of chronic inflammation. Interleukin-1 family (IL-1F) cytokine members are produced by human adipose tissue in obesity. Whereas certain IL-1F members such as IL-1β or IL-18 are potently proinflammatory, others such as IL-1 receptor antagonist (IL-1Ra) or IL-37 (formerly IL-1F7) are antiinflammatory. The NLRP3 inflammasome plays a key role in the processing of bioactive IL-1β and IL-18. We investigated the effect of excessive weight loss on subcutaneous adipose tissue and liver expression of IL-1α, IL-1β, IL-18, IL-1Ra, IL-37 and NLRP3. Twenty-one severely obese patients undergoing laparoscopic adjustable gastric banding were studied. Tissue samples were collected before and 6 months after laparoscopic adjustable gastric banding surgery. mRNA expression of all studied IL-1F members, but especially of IL-37, was much higher in subcutaneous/visceral adipose tissue compared with their liver expression. Subcutaneous adipose tissue mRNA expression of IL-1β decreased significantly after extensive weight loss; expression of IL-18 and IL-1Ra did not change, whereas IL-37 expression increased. Weight loss led to a significant reduction in liver IL-1β, IL-18 and IL-1Ra expression, whereas hepatic IL-37 mRNA expression remained stable. Adipose/liver NLRP3 inflammasome and IL-1α expression were not affected by weight loss. Tissue expression of IL-1β, IL-18 and IL-37 were significantly higher in subcutaneous/visceral adipose tissue compared with the liver. In conclusion, expression of IL-1F members is more pronounced in adipose compared with liver tissue in patients with severe obesity. Excessive weight loss changes the adipose and liver expression profile of IL-1F members toward a more antiinflammatory direction.

Soluble IL-1RII and IL-18 are associated with incipient upper extremity soft tissue disorders

Previous studies suggest a role for IL-1β in the pathophysiology of upper extremity soft tissue disorders (UESTDs). We studied the levels of interleukin-1 family members in patients with incipient UESTDs and compared them with healthy controls. In this case control study, we included 163 patients with UESTDs and symptom duration shorter than 1month and 42 healthy controls matched for age and gender at the group level. Serum levels of cytokines IL-1α, IL-1β, IL-1Ra, IL-6, IL-8, IL-18, IL-33, TNFα and sensitized C-reactive protein as well as IL-1 family soluble receptors sIL-1RII and sST2 were assessed. We used unconditional logistic regression models to study the associations between cytokines and UESTDs. After adjustment for potential confounders, the serum levels of sIL-1RII (p<0.001) and sST2 (p=0.014) were higher in the patients than the controls. The level of IL-18 was lower in the patients than the controls (p=0.005). There were no significant differences between the patients and controls regarding the levels of IL-1α, IL-1β, IL-1Ra, IL-33, IL-6, IL-8, TNFα, or sensitized C-reactive protein. The levels of circulating sIL-1RII and IL-18 are associated with incipient UESTDs, suggesting an important role for these IL-1 family members in the early course of UESTDs.

Hip osteoarthritis susceptibility is associated with IL1B −511(G&gt;A) and IL1 RN (VNTR) genotypic polymorphisms in Croatian caucasian population

Among the predisposing factors to osteoarthritis (OA), a frequent destructive joint disease, is the complex genetic heritage including the interleukin-1 family members like the IL1β (IL1B) and the IL1 receptor antagonist (IL1RN) genes. The aim of this study was to investigate allelic and genotypic frequencies of the IL1B gene single nucleotide polymorphism (SNP) at -511(G>A) and the variable number tandem repeat (VNTR) in the IL1RN gene in a Croatian Caucasian population of hip OA (HOA) cases and healthy controls. A total of 259 HOA patients with total hip replacement (THR) and 518 healthy blood donors as controls were genotyped for IL1B gene SNP -511(G>A) and the VNTR in the IL1RN gene associated with HOA. The genotype G/A (1/2) at IL1B was significantly associated with the protection of the HOA (p < 0.036, OR = 0.72, 95% CI = 0.52-0.99). The genotype G/G (1/1) had only a trend towards the susceptibility (p = 0.053, OR = 1.35, 95% CI = 0.98-1.86) to disease. None of the haplotypes IL1B -511(G>A) and IL1RN (VNTR) were found associated with the HOA. The haplotype 1-2 at these loci had only a trend to susceptibility (p = 0.065). Haplotype 1-3 had a significant male bias in diseased. Furthermore, genotype comprising 2-1/2-2 haplotypes was found significantly associated with predisposition to HOA (p = 0.027, OR = 2.23, 95% CI = 1.03-4.88), whereas genotype 1-1/2-2 with protection to disease (p = 0.028, OR = 0.65, 95% CI = 0.43-0.97). Our findings suggest that HOA in Croatian population might have a different genetic risk regarding the IL1 locus than has been reported for other Caucasian populations previously.

Distinct Expression of Interleukin-1α, Interleukin-1β, and Interleukin-1 Receptor Antagonist in Testicular Tissues and Cells from Human Biopsies with Normal and Abnormal Histology

Cytokines are paracrine/autocrine growth factors known to affect testicular cell functions. The cellular origin and expression levels of interleukin-1 (IL-1) in human normal and pathological testicular biopsies are not yet clear. In the present study, we have investigated the levels and cellular origin of IL-1 family members [IL-1α, IL-β, and IL-1 receptor antagonist (IL-1ra)] in human testicular normal and abnormal biopsies with incomplete maturation arrest (IMA) or Sertoli only syndrome (SOS), using real-time polymerase chain reaction and immunohistochemical staining analysis. Our results show that the levels of IL-1α were higher in Leydig/interstitial cells of biopsies with IMA and SOS compared with normal. The levels of IL-1α in Sertoli cells of normal biopsies were higher than IMA and SOS. The mRNA levels of IL-1α were similar in all biopsies. IL-1β levels were higher in Leydig/interstitial cells of normal biopsies compared with Sertoli and germ cells. The levels of IL-1β were similar in testicular cells of all biopsies. However, the mRNA levels of IL-1β were significantly lower in SOS and IMA biopsies compared with normal. IL-1ra was expressed only in Leydig/interstitial cells, and their expression in normal biopsies was higher than in biopsies with IMA and SOS. The mRNA levels of IL-1ra were similar in all biopsies. Thus, it is possible to suggest the involvement of IL-1 system in the regulation of spermatogenesis and male infertility.

Increased Expression of Interleukin-6 Family Members and Receptors in Urinary Bladder with Cyclophosphamide-Induced Bladder Inflammation in Female Rats

Recent studies suggest that janus-activated kinases–signal transducer and activator of transcription signaling pathways contribute to increased voiding frequency and referred pain of cyclophosphamide (CYP)-induced cystitis in rats. Potential upstream chemical mediator(s) that may be activated by CYP-induced cystitis to stimulate JAK/STAT signaling are not known in detail. In these studies, members of the interleukin (IL)-6 family of cytokines including, leukemia inhibitory factor (LIF), IL-6, and ciliary neurotrophic factor (CNTF) and associated receptors, IL-6 receptor (R) α, LIFR, and gp130 were examined in the urinary bladder in control and CYP-treated rats. Cytokine and receptor transcript and protein expression and distribution were determined in urinary bladder after CYP-induced cystitis using quantitative, real-time polymerase chain reaction (Q-PCR), western blotting, and immunohistochemistry. Acute (4 h; 150 mg/kg; i.p.), intermediate (48 h; 150 mg/kg; i.p.), or chronic (75 mg/kg; i.p., once every 3 days for 10 days) cystitis was induced in adult, female Wistar rats with CYP treatment. Q-PCR analyses revealed significant (p ≤ 0.01) CYP duration- and tissue- (e.g., urothelium, detrusor) dependent increases in LIF, IL-6, IL-6Rα, LIFR, and gp130 mRNA expression. Western blotting demonstrated significant (p ≤ 0.01) increases in IL-6, LIF, and gp130 protein expression in whole urinary bladder with CYP treatment. CYP-induced cystitis significantly (p ≤ 0.01) increased LIF-immunoreactivity (IR) in urothelium, detrusor, and suburothelial plexus whereas increased gp130-IR was only observed in urothelium and detrusor. These studies suggest that IL-6 and LIF may be potential upstream chemical mediators that activate JAK/STAT signaling in urinary bladder pathways.

Usefulness of Soluble Concentrations of Interleukin Family Member ST2 as Predictor of Mortality in Patients With Acutely Decompensated Heart Failure Relative to Left Ventricular Ejection Fraction

The aim of the present study was to determine whether the risk of mortality associated with the concentration of soluble ST2 (sST2) differs in patients with acutely decompensated heart failure with preserved ejection fraction (HFpEF) compared to patients with systolic heart failure. We prospectively enrolled 447 patients with acutely decompensated heart failure. Blood samples were collected at presentation to determine the sST2 concentration. HFpEF was defined as symptoms or signs of acutely decompensated heart failure and left ventricular ejection fraction of ≥50% on the echocardiogram. The patients were followed up for 1 year, and the vital status was obtained for all. The sST2 concentrations were greater in the patients with systolic heart failure (n = 250) than in those with HFpEF (n = 197) at 0.55 versus 0.38 ng/ml (p <0.001). Receiver operating characteristic curve analyses showed different cutoff point values for sST2 for the prediction of 1-year mortality in patients with HFpEF (>0.35 ng/ml) and systolic heart failure (>0.56 mg//ml). These cutoff points had similar prognostic accuracy (area under the curve of 0.69 vs 0.73; p >0.05). In the adjusted analyses that included amino terminal B-type natriuretic peptide concentrations, elevated sST2 concentrations were associated with a greater mortality risk in both populations (HFpEF, per ng/ml, hazard ratio 1.41, 95% confidence interval 1.14 to 1.76, p = 0.002; and systolic heart failure, per ng/ml, hazard ratio 1.20, 95% confidence interval 1.10 to 1.32, p <0.001). The determination of the sST2 concentration improved the clinical risk prediction compared to amino terminal B-type natriuretic peptide, as assessed by both the improved C-statistic and an improvement in the net reclassification index and integrated discrimination improvement analyses. In conclusion, in the present multicenter study, sST2 concentrations were lower in patients with HfpEF; however, sST2 remained an independent predictor of mortality, regardless of the left ventricular ejection fraction.

IL-1 family nomenclature

To the Editor: Newly cloned interleukin 1 (IL-1) family members1–3 were originally given an IL-1 family (IL-1F) designation4, but as functions have now been elucidated for several of these5,6, we propose that each now be assigned an individual interleukin designation. IL-1F6, IL-1F8 and IL-1F9 are encoded by distinct genes but use the same receptor complex (IL-1Rrp2 and AcP), are proinflammatory and deliver nearly identical signals7–12. We propose these be designated IL-36α, IL-36β and IL-36γ, respectively. IL-1F5 also binds to IL-1Rrp2 but antagonizes those cytokines in a manner analogous to that used by IL-1Ra to antagonize IL-1α and IL-1β7–9. We propose that IL-1F5 be renamed IL-36Ra (for ‘receptor antagonist’). In the IL-1 nomenclature, IL-1Ra is used for the natural product, whereas IL-1ra is used for the recombinant product; therefore, IL-36Ra is appropriate for natural IL-1F5. IL-1F7 produces anti-inflammatory effects by suppressing innate immune responses; it does this by decreasing the production of inflammatory cytokines induced by Toll-like receptor agonists as well as that of IL-1 and tumor necrosis factor13,14. We propose this IL-1 family member be renamed IL-37. IL-1F7 has various splice forms1,2,15,16, of which IL-1F7b is the most studied. We propose that IL-1F7a, IL-1F7b and so on be renamed IL-37a, IL-37b and so on. The one remaining IL-1 family member, for which no function has yet been demonstrated, is IL-1F10; however, as evidence of its properties remains limited, we suggest that it retain its IL-1F designation until a function is clearly identified, although it might be prudent to reserve the designation IL-38 for this eventuality.

Interleukin-33 is expressed in differentiated osteoblasts and blocks osteoclast formation from bone marrow precursor cells

Since the hematopoetic system is located within the bone marrow, it is not surprising that recent evidence has demonstrated the existence of molecular interactions between bone and immune cells. While interleukin 1 (IL-1) and IL-18, two cytokines of the IL-1 family, have been shown to regulate differentiation and activity of bone cells, the role of IL-33, another IL-1 family member, has not been addressed yet. Since we observed that the expression of IL-33 increases during osteoblast differentiation, we analyzed its possible influence on bone formation and observed that IL-33 did not affect matrix mineralization but enhanced the expression of Tnfsf11, the gene encoding RANKL. This finding led us to analyze the skeletal phenotype of Il1rl1-deficient mice, which lack the IL-33 receptor ST2. Unexpectedly, these mice displayed normal bone formation but increased bone resorption, thereby resulting in low trabecular bone mass. Since this finding suggested a negative influence of IL-33 on osteoclastogenesis, we next analyzed osteoclast differentiation from bone marrow precursor cells and observed that IL-33 completely abolished the generation of TRACP(+) multinucleated osteoclasts, even in the presence of RANKL and macrophage colony-stimulating factor (M-CSF). Although our molecular studies revealed that IL-33 treatment of bone marrow cells caused a shift toward other hematopoetic lineages, we further observed a direct negative influence of IL-33 on the osteoclastogenic differentiation of RAW264.7 macrophages, where IL-33 repressed the expression of Nfatc1, which encodes one of the key transciption factors of osteoclast differentiation. Taken together, these findings have uncovered a previously unknown function of IL-33 as an inhibitor of bone resorption.

Interleukin family member ST2 and mortality in acute dyspnoea

The study objective was to investigate the prognostic utility and patient-specific characteristics of ST2 (suppression of tumorigenicity 2), assessed with a novel sensitive assay. Suppression of tumorigenicity 2 signalling has been shown to be associated with death in cardiac and pulmonary diseases. In an international multicentre cohort design, we prospectively enrolled 1091 patients presenting with acute dyspnoea to the emergency department (ED). ST2 was measured in a blinded fashion using a novel assay and compared to B-type natriuretic peptide (BNP) and NT-proBNP. The primary end-point was mortality within 30 days and 1 year. The prognostic value of ST2 was evaluated in comparison and in addition to BNP and NT-proBNP. Suppression of tumorigenicity 2 concentrations was higher amongst decedents than among survivors (median 85 vs. 43 U mL⁻¹, P < 0.001) and also higher in patients with impaired left ventricular ejection fraction (LVEF) when compared with preserved LVEF (P < 0.001). In receiver operator characteristics analysis, the area under the curve (AUC) for ST2, BNP and NT-proBNP to predict 30-day and 1-year mortality were 0.76, 0.63 and 0.71, and 0.72, 0.71 and 0.73, respectively. The combinations of ST2 with BNP or NT-proBNP improved prediction of mortality provided by BNP or NT-proBNP alone. After multivariable adjustment, ST2 values above the median (50 U mL⁻¹) significantly predicted 1-year mortality (HR 2.3, P < 0.001). In patients presenting to the ED with acute dyspnoea, ST2 is a strong and independent predictor of 30-day and 1-year mortality and might improve risk stratification already provided by BNP or NT-proBNP.

Fibroblast growth factor receptors 1 and 2 in keratinocytes control the epidermal barrier and cutaneous homeostasis

Fibroblast growth factors (FGFs) are master regulators of organogenesis and tissue homeostasis. In this study, we used different combinations of FGF receptor (FGFR)-deficient mice to unravel their functions in the skin. Loss of the IIIb splice variants of FGFR1 and FGFR2 in keratinocytes caused progressive loss of skin appendages, cutaneous inflammation, keratinocyte hyperproliferation, and acanthosis. We identified loss of FGF-induced expression of tight junction components with subsequent deficits in epidermal barrier function as the mechanism underlying the progressive inflammatory skin disease. The defective barrier causes activation of keratinocytes and epidermal gammadelta T cells, which produce interleukin-1 family member 8 and S100A8/A9 proteins. These cytokines initiate an inflammatory response and induce a double paracrine loop through production of keratinocyte mitogens by dermal cells. Our results identify essential roles for FGFs in the regulation of the epidermal barrier and in the prevention of cutaneous inflammation, and highlight the importance of stromal-epithelial interactions in skin homeostasis and disease.