Distinctive pro-inflammatory gene signatures induced in articular chondrocytes by oncostatin M and IL-6 are regulated by Suppressor of Cytokine Signaling-3.

OBJECTIVE: To describe gene expression in murine chondrocytes stimulated with IL-6 family cytokines and the impact of deleting Suppressor of Cytokine Signaling-3 (SOCS-3) in this cell type. METHOD: Primary chondrocytes were isolated from wild type and SOCS-3-deficient (Socs3(Δ/Δcol2)) mice and stimulated with oncostatin M (OSM), IL-6 plus the soluble IL-6 receptor (IL-6/sIL-6R), IL-11 or leukemia inhibitory factor (LIF) for 4 h. Total RNA was extracted and gene expression was evaluated by microarray analysis. Validation of the microarray results was performed using Taqman probes on RNA derived from chondrocytes stimulated for 1, 2, 4 or 8 h. Gene ontology was characterized using DAVID (database for annotation, visualization and integrated discovery). RESULTS: Multiple genes, including Bcl3, Junb, Tgm1, Angptl4 and Lrg1, were upregulated in chondrocytes stimulated with each gp130 cytokine. The gene transcription profile in response to OSM stimulation was pro-inflammatory and was highly correlated to IL-6/sIL-6R, rather than IL-11 or LIF. In the absence of SOCS-3, OSM and IL-6/sIL-6R stimulation induced an interferon (IFN)-like gene signature, including expression of IL-31ra and S100a9. CONCLUSION: While each gp130 cytokine induced a transcriptional response in chondrocytes, OSM- and IL-6/sIL-6R were the most potent members of this cytokine family. SOCS-3 plays an important regulatory role in this cell type, as it does in hematopoietic cells. Our results provide new insights into a hierarchy of gp130-induced transcriptional responses in chondrocytes that is normally restrained by SOCS-3 and suggest therapeutic inhibition of OSM may have benefit over and above antagonism of IL-6 during inflammatory arthritis.

Interleukins-12 and -23 do not alter expression or activity of multiple cytochrome P450 enzymes in cryopreserved human hepatocytes.

Psoriasis is a T-cell-mediated autoimmune disease involving the skin. Two cytokines, interleukin-12 (IL-12) and IL-23 have been shown to play a pivotal role in the pathogenesis of the disease. Ustekinumab (Stelara) is a therapeutic monoclonal antibody (mAb) targeted against the p40 shared subunit of IL-12 and IL-23. Recently the ability of therapeutic proteins (TP) including mAbs that target either cytokines directly (e.g., Pegasys; peginterferon α-2a) or their respective cell surface receptors [e.g., tocilizumab (Actemra); anti IL-6R] to desuppress cytochrome P450 (P450) enzymes in vitro and in the clinic, has been demonstrated. In the present study the ability of IL-12 and IL-23 to suppress multiple P450 enzymes was investigated in vitro using six separate lots of cultured human hepatocytes. Following exposure of 10 ng/ml IL-12 and IL-23 for 48 hours, either alone or in combination, no change in CYP2B6, 2C9, 2C19, or 3A4 gene expression or functional activity was observed. None of the untreated hepatocyte donors showed appreciable expression of the IL-12 or IL-23 receptors. Similar results were seen with whole human liver samples. Exposure of hepatocytes to IL-12 and/or IL-23, known P450 suppressors (IL-6 and tumor necrosis factor-α) or known P450 inducers (ß-naphthoflavone, phenobarbital, and rifampicin) did not appreciably alter the expression of the IL-12 and IL-23 receptors either. Finally, in contrast to the positive control IL-6, expression of the acute phase C-reactive protein was unaltered following IL-12 and/or IL-23 treatment. Together, these data suggest a negligible propensity for IL-12 or IL-23 to directly alter P450 enzymes in human hepatocytes.

Inflammation and neural signaling: etiologic mechanisms of the cancer treatment-related symptom cluster.

PURPOSE OF REVIEW: Cancer patients undergoing treatment with cytotoxic chemotherapeutic agents (CCAs) often experience a cluster of treatment-related symptoms, which include fatigue, loss of appetite, disturbed sleep, depressed mood, cognitive difficulties, and changes in body composition. This symptom cluster collectively referred to herein as cancer treatment-related symptoms (CTRSs) decrease quality of life, and physical and social functioning. The preclinical and clinical studies described in this review represent important progress in understanding potential underlying mechanisms of CTRS. RECENT FINDINGS: Recent studies support a role for CCA-induced interleukin-1ß (IL-1ß) signaling in the cause of CTRS. CCAs may share a common ability to activate intracellular stress response pathways to trigger the synthesis, processing, and release of IL-1ß from immune cells. Fatigue, sleep disturbance, and cognitive difficulties in cancer patients exposed to CCAs correlate with plasma levels of IL-6, IL-1 receptor antagonist, and soluble tumor necrosis factor receptor-I/II, surrogate markers of IL-1ß-mediated central nervous system (CNS) inflammation. Additional preclinical work suggests IL-1ß-mediated CNS inflammation may cause CTRS by altering hypothalamic and hippocampal functioning. SUMMARY: Although additional research is necessary to further establish the link between CCA exposure, IL-1ß-mediated inflammatory processes and CTRS, these data provide hints for future studies and therapeutic approaches in ameliorating these symptoms in cancer patients.

IL-1 pathways in inflammation and human diseases.

Interleukin (IL)-1 was first cloned in the 1980s, and rapidly emerged as a key player in the regulation of inflammatory processes. The term IL-1 refers to two cytokines, IL-1alpha and IL-1beta, which are encoded by two separate genes. The effects of IL-1 are tightly controlled by several naturally occurring inhibitors, such as IL-1 receptor antagonist (IL-1Ra), IL-1 receptor type II (IL-1RII), and other soluble receptors. Numerous IL-1 inhibitors have been developed and tested primarily in rheumatoid arthritis, with only modest effects. By contrast, the use of IL-1 antagonists has been uniformly associated with beneficial effects in patients with hereditary autoinflammatory conditions associated with excessive IL-1 signaling, such as cryopyrinopathies and IL-1Ra deficiency. Successful treatment with IL-1 blockers has also been reported in other hereditary autoinflammatory diseases, as well as in nonhereditary inflammatory diseases, such as Schnizler syndrome, systemic-onset juvenile idiopathic arthritis and adult Still disease. The role of microcrystals in the regulation of IL-1beta processing and release has provided the rationale for the use of IL-1 inhibitors in crystal-induced arthritis. Finally, preliminary results indicating that IL-1 targeting is efficacious in type 2 diabetes and smoldering myeloma have further broadened the spectrum of IL-1-driven diseases.

Modulation of CLA, IL-12R, CD40L, and IL-2Ralpha expression and inhibition of IL-12- and IL-23-induced cytokine secretion by CNTO 1275.

Cytokines interleukin (IL)-12 and IL-23 are implicated in the pathogenesis of psoriasis. IL-12 causes differentiation of CD4+ T cells to interferon-gamma (IFN-gamma)-producing T helper 1 (Th1) cells, while IL-23 induces differentiation to IL-17-producing pathogenic Th17 cells. The effects of the monoclonal antibody to IL-12/23 p40 subunit (CNTO 1275) on IL-12 receptor (IL-12R) expression, markers associated with skin homing, activation, and cytokine secretion were investigated in vitro using human peripheral blood mononuclear cells (PBMCs) from healthy donors. PBMCs were activated in the presence or absence of recombinant human (rh) IL-12 or rhIL-23, with or without CNTO 1275. CNTO 1275 inhibited upregulation of CLA, IL-12R, IL-2Ralpha and CD40L expression and also inhibited IL-12- and IL-23-induced IFN-gamma, IL-17A, tumor necrosis factor (TNF)-alpha, IL-2, and IL-10 secretion. Thus, the therapeutic effect of CNTO 1275 may be attributed to the IL-12/23 neutralization, resulting in decreased expression of skin homing and activation markers, and IL-12- and IL-23-induced cytokine secretion.

The IL-4 and IL-13 pseudomonas exotoxins: new hope for brain tumor therapy.

Targeting cell surface receptors with cytotoxins or immunotoxins provides a unique opportunity for brain tumor therapy. The authors have discovered that receptors for two cytokines, interleukin (IL)-4 and IL-13, are overexpressed on tumor biopsy samples and on cell lines derived from a variety of human tumors, including brain tumors. These investigators have demonstrated that the structure of these cytokine receptors on tumor cells is different from that found on normal immune cells. In human solid tumor cells, IL-4 binds to two chains (IL-4Ra and IL-13Ra1), whereas IL- 13 binds to three chains in many solid tumor cells, including glioma cells (to IL-4Ra, IL-13Ra1, and IL-13Ra2). To target IL-4Rs and IL-13Rs, the authors generated two recombinant fusion cytotoxins composed of IL-4 or IL-13 and a mutated form of pseudomonas exotoxin (PE), which for simplicity are called IL4-PE and IL13-PE in this paper. These chimeric cytotoxins are highly toxic in vitro to human tumor cell lines and primary cell cultures, including glioma cells, and in vivo to animal models of human tumors, including gliomas. In contrast, normal cells, including immune, endothelial, and brain cells, are spared from their cytotoxic effects. Based on numerous preclinical studies, IL13-PE (also known as IL13-PE38QQR or cintredekin besudotox) has been tested in four Phase I/II clinical trials. The agent IL13-PE was administered intracranially by using convection-enhanced delivery (CED). The drug was delivered through catheters placed either directly into the tumor bed or in the peritumoral region after resection of the lesion. The CED of IL13-PE was fairly well tolerated, with a reasonable benefit/risk profile for treatment of patients with glioma. Based on Phase I/II clinical trials, the Phase III Randomized Evaluation of CED of IL13-PE Compared to Gliadel Wafer with Survival Endpoint Trial (also known as the PRECISE Trial) in patients with initial recurrence of glioblastoma multiforme has recently been completed. Patients are being monitored for safety of the agents, duration of overall survival, and quality of life.

Efficacy of antiangiogenic targeted toxins against glioblastoma multiforme.

OBJECT: Because the prognosis for patients with glioblastoma multiforme (GBM) remains poor, investigators have focused on developing new and more effective treatment modalities. Targeted toxins represent a new class of compounds composed of a potent protein toxin and a carrier ligand that will recognize cell surface antigens located on target tissue. A recombinant fusion protein was created that contains the translocation and catalytic portions of diphtheria toxin that are responsible for cell entry and killing, respectively, fused to the noninternalizing aminoterminal fragment portion of human plasminogen activator. This diptheria toxin-uPA fusion protein (DTAT) has the advantage over other fusion proteins of targeting malignant glioma cells and the endothelial cells of the neovasculature that express the urokinase-type plasminogen activator receptor (uPAR). Another protein, DTAT13, was synthesized to target uPAR on the neovasculature and the uPAR and interleukin-13 receptor-expressing GBM cells. The authors describe the in vitro and in vivo efficacy of DTAT and DTAT13 against GBM. METHODS: The in vitro cytotoxicity of DTAT and DTAT13 was measured using cell proliferation assays. In vivo studies were performed in which DTAT, DTAT13, or a control protein was injected directly into GBM flank tumors in athymic nude mice. Tumor volume was assessed over time and analyzed using the Student t-test. The systemic organ effects of DTAT and DTAT13 were examined functionally and histologically in tumor-free C57BL/6 mice. In vitro, DTAT and DTAT13 were found to be highly potent and selective against U118MG, U87MG, and U373MG GBM cell lines and human umbilical vein endothelial cells. In vivo, DTAT and DTAT13 both caused a statistically significant (p < 0.05) regression of U87MG GBM flank tumors when administered every other day at 10 mg/day for five doses. No tumor regression was seen in control animals. Both DTAT and DTAT13 had little effect on histological findings in the liver, kidney, spleen, and lungs. Serum analysis did not demonstrate an effect on blood urea nitrogen levels, but liver alanine aminotransferase levels rose to statistically significant (p = 0.046) but not life-threatening levels. Also, DTAT13 was less toxic than DTAT in studies of mortality rates. CONCLUSIONS: Both DTAT and DTAT13 might have potential for clinical application against GBM because of their ability to target both the tumor cells and neovasculature simultaneously with an absence of serious systemic side effects. The discovery that DTAT13 was less toxic than DTAT indicated that the bispecific fusion protein might target a broader subset of antigenetically diverse patients with tumors while reducing the systemic exposure to toxin that would be necessary if two agents were administered separately.

TNF-alpha and IFN-gamma inversely modulate expression of the IL-17E receptor in airway smooth muscle cells.

The interleukin-17B receptor (IL-17BR) is expressed in a variety of tissues and is upregulated under inflammatory conditions. This receptor binds both its cognate ligand IL-17B and IL-17E/IL-25, a novel cytokine known to promote Th2 responses. The present study shows that airway smooth muscle cells express IL-17BR in vitro and that its expression is upregulated by TNF-alpha and downregulated by IFN-gamma. Our data indicate that TNF-alpha upregulates IL-17BR mainly through nuclear factor-kappaB as assessed with the IkappaB kinase 2 inhibitor AS-602868. In addition, both IFN-gamma and dexamethasone are able to antagonize a TNF-alpha-induced IL-17BR increase in mRNA expression. The mitogen-activated protein kinase kinase inhibitor U0126 totally reversed the inhibition observed with IFN-gamma, suggesting the involvement of the extracellular signal-regulated kinase pathway in this effect. In addition, on stimulation with IL-17E, airway smooth muscle cells increase their expression of ECM components, namely procollagen-alphaI and lumican mRNA. Furthermore, immunohistochemical analysis of biopsies from asthmatic subjects reveals that this receptor is abundant in smooth muscle layers. This is the first report showing IL-17BR receptor in structural cells of the airways. Our results suggest a potential proremodeling effect of IL-17E on airway smooth muscle cells through the induction of ECM and that its receptor is upregulated by proinflammatory conditions.

Biological effects of a dietary omega-3 polyunsaturated fatty acids supplementation in cystic fibrosis patients: a randomized, crossover placebo-controlled trial.

BACKGROUND AND AIMS: Various anti-inflammatory therapies, including dietary omega-3 polyunsaturated fatty acids (PUFA) supplementation, have been investigated in cystic fibrosis (CF) patients. To further explore this nutritional approach, biological effects of an omega-3 PUFA oral liquid supplementation were measured in 17 CF patients in a double-blind, randomized, crossover without a washout period and placebo-controlled study. METHODS: CF patients (age: 18+/-9 year; weight: 43+/-13 kg) received a liquid dietary supplementation either enriched or not in omega-3 PUFA (390-1170 mg/day according to patient weight) during two 6-month periods. RESULTS: Increase in eicosapentaenoic acid was observed in neutrophil membrane following omega-3 PUFA dietary supplementation (from 0.7+/-0.6 to 1.6+/-0.6 micromol%, P<0.01). The leukotriene B(4) (LTB(4))/leukotriene B(5) (LTB(5)) ratio was decreased (from 72+/-27 to 24+/-7, P<0.001) in CF patients taking omega-3 PUFA supplements. In contrast, omega-3 PUFA supplementation affected neither internalization of IL-8 receptors following IL-8 exposure, nor IL-8-induced neutrophil chemotaxis. CONCLUSION: Our results show that omega-3 PUFA are incorporated in neutrophil membranes. The subsequent decrease in LTB(4)/LTB(5) ratio suggests that, in such conditions, neutrophils may produce less pro-inflammatory mediators from the acid arachidonic pathway. These data indicate that omega-3 PUFA intake may have anti-inflammatory effect that still need to be assessed by long-term studies following large groups of patients.

Preoperative statin therapy does not reduce cognitive dysfunction after cardiopulmonary bypass.

OBJECTIVE: The purpose of this study was to determine if patients receiving statin therapy before coronary artery bypass grafting surgery would have less cognitive dysfunction after cardiopulmonary bypass as a consequence of a diminished inflammatory response. DESIGN: Retrospective observational study of patients undergoing coronary artery bypass grafting surgery. SETTING: Referral center for cardiothoracic surgery at a university hospital. PARTICIPANTS: Four hundred forty patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirty-five percent of patients received statins in the preoperative period. Multivariable analysis revealed no effect of preoperative statin therapy on cognitive function (p = 0.67). Post hoc analysis revealed that statin therapy at hospital discharge was associated with less improvement in cognitive performance at 6 weeks after surgery (p = 0.011). No significant differences were found between statin therapy groups in either range or maximum value of any of the cytokines (p > 0.05). CONCLUSIONS: Preoperative statin therapy did not decrease the inflammatory response to cardiopulmonary bypass or the cognitive dysfunction commonly seen after cardiac surgery.

Combined effects of radiation and interleukin-13 receptor-targeted cytotoxin on glioblastoma cell lines.

PURPOSE: Interleukin-13 receptor-targeted cytotoxin (IL13-PE38) is highly cytotoxic to human glioblastoma (GBM) cells. Although this molecule is being tested in a multicenter Phase III clinical trial (PRECISE Study) in patients with recurrent disease, the activity of IL13-PE38 when combined with radiation therapy has not been investigated. METHODS AND MATERIALS: Cytotoxicity of IL13-PE38 to GBM cell lines was assessed by protein synthesis inhibition and clonogenic assays, and the growth of GBM cells receiving radiation was assessed by thymidine uptake assays. Expression of IL-13 receptor alpha2 (IL-13Ralpha2) messenger ribonucleic acid (mRNA) in GBM cells exposed to radiation was assessed by quantitative reverse transcriptase/polymerase chain reaction (RT-PCR) and IL-13R density by radiolabeled IL-13 binding assays. RESULTS: Prior irradiation of GBM cell lines followed by IL13-PE38 treatment did not enhance cytotoxicity; however, concomitant 5 Gy irradiation and IL13-PE38 treatment was highly cytotoxic to T98G, M059K, A172, and LN-229 cell lines as determined by cell viability assays. There was a statistically significant decrease in number of viable cells in IL13-PE38 and irradiated cells compared with irradiated cells alone (p < 0.05) or IL13-PE38 treated cells alone (p < 0.05). In contrast, U251, SN19, and U87MG cell lines did not show any combined effect. These results were confirmed by clonogenic assays. Although three GBM cell lines-U251, SN19, and A172-showed 2.8- to 13.9-fold upregulation of IL-13Ralpha2 mRNA expression at 6-24 h after exposure to 5 Gy radiation, specific binding of radiolabeled IL-13 to these cell lines did not improve. CONCLUSIONS: Our results suggest that concomitant radiation therapy and IL13-PE38 treatment may be beneficial for the treatment of patients with GBM. This strategy may be worth exploring in animal models of human glioma.

Analysis of target genes induced by IL-13 cytotoxin in human glioblastoma cells.

IL-13 cytotoxin comprised of IL-13 and a mutated form of Pseudomonas exotoxin (fusion protein termed IL-13-PE38QQR) has been shown to inhibit protein synthesis leading to necrotic and apoptotic cell death in glioblastoma cells that express high levels of interleukin-13 receptors (IL-13R). To identify target genes of cell death and other cellular genes with IL-13 receptors in glioblastoma cells, we utilized the cDNA microarrays to analyze global gene expression profiles after IL-13 cytotoxin and IL-13 treatment. IL-13 cytotoxin mediated cytotoxicity to U251 cells in a dose-dependent manner. Hierarchical cluster analysis of differentially expressed genes in U251 glioma cells at different time points after IL-13 cytotoxin treatment showed three major groups, each representing a specific expression pattern. Randomly selected differentially expressed genes from each group were confirmed by RT-PCR analysis. Most down-regulated genes belong to cell adhesion, motility, angiogenesis, DNA repair, and metabolic pathways. While up-regulated genes belong to cell cycle arrest, apoptosis, signaling and various metabolic pathways. Unexpectedly, at early time points, both IL-13 and IL-13 cytotoxin induced several genes belonging to different pathways most notably IL-8, DIO2, END1, and ALDH1A3 indicating that these genes are early response genes and their products may be associated with IL-13R. In addition, IL-13 cytotoxin induced IL-13Ralpha2 mRNA expression during the treatment in glioma cells. Our results indicate that novel cellular genes are involved with IL-13 receptors and that IL-13 cytotoxin induced cell death involves various target genes in human glioblastoma cells. On going studies will determine the role of associated genes and their products in the IL-13R functions in glioma cells.

MyD88-deficient mice develop severe intestinal inflammation in dextran sodium sulfate colitis.

BACKGROUND: Gut commensal microbes affect the development and activation of the mucosal and systemic immune systems. However, the exact molecular mechanism of these microbes that is involved in the development of colitis remains unclear. METHODS: The present study was conducted to determine the distinct role of the innate immune system in the development of a dextran sulfate sodium (DSS) colitis model in MyD88(-/-) mice, because myeloid differentiation protein (MyD88) is a major adaptor molecule essential for signaling via Toll-like receptors (TLRs). To this end, MyD88(-/-) and wild-type (WT) mice received sterile distilled water containing 1.2% DSS for 8 days. The survival rate, total clinical score (body weight loss, stool consistency, and rectal bleeding), colon length, and histological score were assessed. The expression of surface markers (F4/80 and CD4) on infiltrating lamina propria mononuclear cells was analyzed immunohistochemistrically. RESULTS: MyD88(-/-) mice exhibited increased susceptibility to DSS-induced colitis, as reflected by significantly higher lethality and higher clinical and histological scores, and more severe colonic shortening compared to WT mice. Immunohistochemical analysis revealed a significant increase of both F4/80+ macrophages and CD4+ T cells in the inflamed mucosa in DSS-fed MyD88(-/-) mice compared to DSS-fed WT mice. CONCLUSIONS: These findings suggest that, via MyD88 signaling, the innate immune system in the gut plays an important protective role in colitis.

Interleukin-22 activates STAT3 and induces IL-10 by colon epithelial cells.

Human interleukin-22 (IL-22), a cytokine with structural homology to IL-10, is produced by activated T cells. The IL-22 receptor complex consists of a ligand-binding chain, the IL-22R1 and a signal-transducing chain, the IL-10R2. The aim of this study is to identify potential target cells and associated biological activity of IL-22 by identifying cell types that specifically express high levels of IL-22R1 as the expression of IL-10R2 is ubiquitous. Expression of IL-22R1 mRNA, as analyzed by real time quantitative polymerase chain reaction (PCR), was observed in human tumor cell lines of stromal or epithelial origin derived from liver, pancreas, colon and lung tissue. Furthermore, we examined the ability of IL-22 to activate the JAK-Signal Transducer and Activator of Transcription (STAT) pathway in epithelial cells of the colon. IL-22 induced the phosphorylation of STAT1 and STAT3 in Colo205, a colon epithelial cell line. Consequently, IL-22 upregulated mRNA for Suppressor of Cytokine Signaling 3 (SOCS3), a STAT3-responsive gene. Further analyses, by real time quantitative PCR, on a panel of chemokines and immune function related genes revealed that IL-22 induced expression of the acute phase proteins alpha-Antichymotrypsin and Serum Amyloid A, as well as IL-10 mRNA and protein production by Colo205. Induction of IL-10 by IL-22, in Colo205 cells, could be inhibited in the presence of a neutralizing antibody against IL-10R2. IL-22-mediated effects on the Colo205 cells were also inhibited in the presence of IL-22 binding protein (IL-22BP), a soluble receptor with structural similarity to IL-22R1. The high levels of expression of IL-22R1 observed in epithelial cells of the colon and the ability of IL-22 to upregulate production of acute phase proteins and IL-10 in Colo205 cells, suggest a functional role for IL-22 in intestinal inflammation.

Influence of thyroxine on serum soluble interleukin-2 receptor alpha levels in thyroid disorders.

BACKGROUND: Activation of cell-mediated immunity by soluble interleukin-2 receptor alpha (sIL-2Ralpha) release is well documented. The aim of this study was to measure serum concentrations of sIL-2Ralpha in patients with autoimmune and non-autoimmune thyroid disorders in different stages of thyroid function, before and after administration of l-thyroxine (l-T4) and its discontinuation as well as before and during methimazole administration. MATERIALS AND METHODS: The study included 80 females: 16 with Graves' disease, 15 with Hashimoto's thyroiditis and subclinical hypothyroidism, 14 with Hashimoto's thyroiditis with fibrosis and clinical hypothyroidism, 20 after subtotal thyroidectomy following nodular non-toxic goitre and 15 healthy controls. Patients were examined at two different time points. Serum concentrations of sIL-2Ralpha were measured with the use of enzyme immunoassay technique. RESULTS: Souble IL-2Ralpha serum concentration increased in patients with untreated Graves' disease and decreased after methimazole treatment. In Hashimoto's thyroiditis, the sIL-2Ralpha level was within the normal range, in Hashimoto's thyroiditis with clinical hypothyreosis it was low and after l-T4 administration it increased in both patient groups. After thyroidectomy, patients treated with l-T4, had increased levels of sIL-2Ralpha which decreased after discontinuation of therapy. There were a significant positive correlation between sIL-2Ralpha and free thyroxine in patients with (i). Graves' disease both before and after methimazole administration, (ii). Hashimoto's thyroiditis (with subclinical hypothyroidism) both before and after l-T4 therapy, (iii). Hashimoto's thyroiditis with fibrosis and (iv). overt hypothyroidism before l-T4 administration and in individuals during long-term l-T4 treatment (after subtotal thyroidectomy). CONCLUSION: Serum sIL-2Ralpha concentration in autoimmune thyroid diseases depends on thyroid function. In both autoimmune and non-autoimmune thyroid diseases, thyroxine stimulates the release of sIL-2Ralpha.

Characterization of the effect of interleukin-10 on silica-induced lung fibrosis in mice.

We previously described a reduction of silica-induced lung fibrosis in interleukin-10-deficient mice (IL-10-/-) (Huaux and colleagues; Am. J. Respir. Cell Mol. Biol. 1998;18:51-59). In the present study, we further dissect the exact functions of IL-10 in experimental silicosis. The reduced lung fibrotic response to silica in IL-10-/- mice was accompanied by a marked recruitment of TH1 CD4+ lymphocytes. However, treatment with anti-CD4 antibodies reduced silica-induced lung fibrosis in both IL-10-/- and IL-10+/+ mice, suggesting that this T cell population actually contributes to the extension of the fibrotic lesions in a manner that is independent of IL-10. In IL-10-/- mice, silica-induced lung production of the profibrotic mediator transforming growth factor (TGF)-beta1 and the antifibrotic eicosanoid PGE2 were reduced and increased, respectively, relative to that in IL-10+/+ mice. In addition, in vitro experiments indicated that recombinant IL-10 upregulated TGF-beta1 expression in alveolar macrophages while in contrast it downregulated PGE2 production and cyclooxygenase-2 expression in both lung fibroblasts and macrophages. Thus the net profibrotic activity of IL-10 in vivo appears to be mediated by its ability to stimulate the expression of the profibrotic cytokine TGF-beta1 while suppressing the expression of cyclooxygenase-2 and thus production of the antifibrotic eicosanoid PGE2. These effects appear to be independent of the enhanced lung CD4+ T-lymphocytosis observed in IL-10-deficient mice.

Pathophysiological roles for IL-18 in inflammatory arthritis.

IL-18 is a unique cytokine with prominently wide spectrum biological actions. Among these, its IFN-gamma/TNF-alpha-inducing activity primarily contributes to the development of various inflammatory diseases including inflammatory arthritis. IL-18 levels correlate with the disease activity of rheumatoid arthritis (RA) and osteoarthritis (OA). IL-18 is spontaneously released from RA synovial cells and OA chondrocytes and seems to participate in the development of the inflammatory and destructive alterations of joints via induction of TNF-alpha, a potent effector molecule. TNF-alpha, in turn, increases IL-18 expression in RA synovial cells. Recent clinical trials have revealed the efficacy of TNF-alpha in RA with a reduction in circulatory IL-18 levels. These may implicate the positive circuit between IL-18 and TNF-alpha for development of RA. As IL-18-deficient mice evade collagen-induced arthritis in a mouse RA model, therapeutics targeting IL-18 may be beneficial against RA/OA. Here, the authors review the possible roles of IL-18 in inflammatory arthritis.

MIP-T3 associates with IL-13Ralpha1 and suppresses STAT6 activation in response to IL-13 stimulation.

To unravel the mechanism of interleukin-13 (IL-13)-specific functions, we sought to identify IL-13 receptor (IL-13R) binding molecules. A novel human IL-13Ralpha1 binding protein (IL13RBP1) has been identified using yeast tri-hybrid system, which was found to encode the same protein as MIP-T3 (microtubule interacting protein that associates with tumor necrosis factor (TNF) receptor associating factor-3 (TRAF3)). It constitutively associates with IL-13Ralpha1 and suppresses IL-4/13-induced signal transducer and activator of transcription-6 (STAT6) phosphorylation. IL-13-induced STAT6 activation was also inhibited as determined by dual luciferase assay and electrophoretic mobility shift assay (EMSA). These results suggest that MIP-T3 is a novel inhibitor of IL-13 signaling and may be a useful molecule in ameliorating various conditions in which IL-13 plays a central role.

Improved anti-tumor activity and safety of interleukin-13 receptor targeted cytotoxin by systemic continuous administration in head and neck cancer xenograft model.

BACKGROUND: IL-13 receptor (IL-13R) targeted cytotoxin, IL13-PE38QQR, has been shown to have very potent anti-tumor activity to IL-13R-expressing head and neck tumor cells in vitro and in vivo. However, its effect is limited in aggressive tumors. To further improve the anti-tumor activity and safety of IL-13 cytotoxin, we employed continuous infusion technique in animal model of head and neck cancer. MATERIALS AND METHODS: We surgically implanted continuous infusion (CI) pump intraperitoneally that released drug for 7 days, and its anti-tumor effect was evaluated. A comparison was made for antitumor activity and safety with intravenously (IV) administered IL-13 cytotoxin in a head and neck (KCCT873 and HN12) subcutaneous (SC) xenograft tumor models in nude mice. Vital organ toxicities were assessed by histologic examinations and blood serum chemistry analyses. RESULTS: The 50 or 75 micro g/kg/day for 7 days of IL-13 cytotoxin either by IV or CI administration did not show any difference in safety or anti-tumor activity. IV administration of 150 or 200 micro g/kg/day of IL-13 cytotoxin for 7 days was lethal to nude mice, whereas 200 micro g/kg/day X 7 days of CI administration was highly effective in the regression of established tumors without any toxicities. Additionally, CI administration of IL-13 cytotoxin (200 micro g/kg/day) showed growth inhibition of larger HN12 tumors in nude mice. CONCLUSION: With a CI schedule, IL-13 cytotoxin can be systemically administrated at approximately twice the dose otherwise given by daily IV bolus administration.