Treponema denticola stimulates Oncostatin M cytokine release and de novo synthesis in neutrophils and macrophages.

Oncostatin M (OSM) is a pleiotropic cytokine elevated in a number of inflammatory conditions including periodontal disease. OSM is produced by a variety of immune cells and has diverse functionality such as regulation of metabolic processes, cell differentiation, and the inflammatory response to bacterial pathogens. The oral cavity is under constant immune surveillance including complementary neutrophil and macrophage populations, due to a persistent symbiotic bacterial presence. Periodontal disease is characterized by a dysbiotic bacterial community, with an abundance of Treponema denticola. Despite strong associations with severe periodontal disease, the source and mechanism of the release of OSM have not been defined in the oral cavity. We show that OSM protein is elevated in the gingival epithelium and immune cell infiltrate during periodontal disease. Furthermore, salivary and oral neutrophil OSM is elevated in correlation with the presence of T. denticola. In an air pouch infection model, T. denticola stimulated higher levels of OSM than the oral pathogen Porphorymonas gingivalis, despite differential recruitment of innate immune cells suggesting T. denticola has distinct properties to elevate OSM levels. OSM release and transcription were increased in isolated human blood, oral neutrophils, or macrophages exposed to T. denticola in vitro as measured by ELISA, qPCR, and microscopy. Using transcription, translation, and actin polymerization inhibition, we found that T. denticola stimulates both OSM release through degranulation and de novo synthesis in neutrophils and also OSM release and synthesis in macrophages. Differential induction of OSM by T. denticola may promote clinical periodontal disease.

In vivo affinity and target engagement in skin and blood in a first-time-in-human study of an anti-oncostatin M monoclonal antibody.

AIMS: The oncostatin M (OSM) pathway drives fibrosis, inflammation and vasculopathy, and is a potential therapeutic target for inflammatory and fibrotic diseases. The aim of this first-time-in-human experimental medicine study was to assess the safety, tolerability, pharmacokinetics and target engagement of single subcutaneous doses of GSK2330811, an anti-OSM monoclonal antibody, in healthy subjects. METHODS: This was a phase I, randomized, double-blind, placebo-controlled, single-dose escalation, first-time-in-human study of subcutaneously administered GSK2330811 in healthy adults (NCT02386436). Safety and tolerability, GSK2330811 pharmacokinetic profile, OSM levels in blood and skin, and the potential for antidrug antibody formation were assessed. The in vivo affinity of GSK2330811 for OSM and target engagement in serum and skin blister fluid (obtained via a skin suction blister model) were estimated using target-mediated drug disposition (TMDD) models in combination with compartmental and physiology-based pharmacokinetic (PBPK) models. RESULTS: Thirty subjects were randomized to receive GSK2330811 and 10 to placebo in this completed study. GSK2330811 demonstrated a favourable safety profile in healthy subjects; no adverse events were serious or led to withdrawal. There were no clinically relevant trends in change from baseline in laboratory values, with the exception of a reversible dose-dependent reduction in platelet count. GSK2330811 exhibited linear pharmacokinetics over the dose range 0.1-6 mg kg-1 . The estimated in vivo affinity (nM) of GSK2330811 for OSM was 0.568 [95% confidence interval (CI) 0.455, 0.710] in the compartmental with TMDD model and 0.629 (95% CI 0.494, 0.802) using the minimal PBPK with TMDD model. CONCLUSIONS: Single subcutaneous doses of GSK2330811 were well tolerated in healthy subjects. GSK2330811 demonstrated sufficient affinity to achieve target engagement in systemic circulation and target skin tissue, supporting the progression of GSK2330811 clinical development.

Oncostatin M induces tumorigenic properties in non-transformed human prostate epithelial cells, in part through activation of signal transducer and activator of transcription 3 (STAT3).

Prostate cancer is one of the most common types of cancer in men in Western countries. Chronic inflammation in the prostate, regulated by a complex network of factors including inflammatory cytokines, is one of the established risk factors for development of prostate cancer. Interleukin-6 (IL-6) is a well-known promoter of inflammation-induced carcinogenesis and disease progression in prostate cancer. Presence in the prostate and possible roles in tumor development by other members of the IL-6 family of cytokines have, however, been less studied. Here we show that the IL-6-type cytokine oncostatin M (OSM) indeed induce cellular properties associated with tumorigenesis and disease progression in non-transformed human prostate epithelial cells, including morphological changes, epithelial-to-mesenchymal transition (EMT), enhanced migration and pro-invasive growth patterns. The effects by OSM were partly mediated by activation of signal transducer and activator of transcription 3 (STAT3), a transcription factor established as driver of cancer progression and treatment resistance in numerous types of cancer. The findings presented here further consolidate IL-6-type cytokines and STAT3 as promising future treatment targets for prostate cancer.

Anti-OSM Antibody Inhibits Tubulointerstitial Lesion in a Murine Model of Lupus Nephritis.

The purpose of this study was to investigate the role of oncostatin M (OSM) in tubulointerstitial lesion (TIL) in lupus nephritis (LN). We found that OSM was highly expressed in the renal tissue of LN mice. OSM is one of the interleukin-6 cytokine family members. In order to clarify the role and mechanism of OSM in LN, mice with LN were treated with anti-OSM antibody or isotype antibody. We evaluated the tubular epithelial-mesenchymal transdifferentiation (EMT) by detecting the E-cadherin, α-smooth muscle actin (α-SMA), and fibronectin (FN) expression. We analyzed the inflammation by observing the monocyte chemotactic factor-1 (MCP-1) and intercellular adhesion molecule (ICAM-1) expression and calculated the tubulointerstitial fibrosis area by Masson staining. The results showed that anti-OSM antibody, rather than isotype antibody, improved EMT, inflammation, and tubulointerstitial fibrosis. In addition, the signal transducer and activator of transcription (STAT) 1 and STAT3 signaling was activated by tyrosine phosphorylation in LN mouse renal tissue, indicating that the phosphorylated STAT1 (p-STAT1) and p-STAT3 were involved in kidney injury. Moreover, decreased p-STAT3 instead of p-STAT1 has been observed after anti-OSM antibody injection. Thus, we concluded that OSM is associated with TIL in lupus nephritis, which may be connected with the activation of STAT3 rather than that of STAT1.

Oncostatin M drives intestinal inflammation and predicts response to tumor necrosis factor-neutralizing therapy in patients with inflammatory bowel disease.

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex chronic inflammatory conditions of the gastrointestinal tract that are driven by perturbed cytokine pathways. Anti-tumor necrosis factor-α (TNF) antibodies are mainstay therapies for IBD. However, up to 40% of patients are nonresponsive to anti-TNF agents, which makes the identification of alternative therapeutic targets a priority. Here we show that, relative to healthy controls, inflamed intestinal tissues from patients with IBD express high amounts of the cytokine oncostatin M (OSM) and its receptor (OSMR), which correlate closely with histopathological disease severity. The OSMR is expressed in nonhematopoietic, nonepithelial intestinal stromal cells, which respond to OSM by producing various proinflammatory molecules, including interleukin (IL)-6, the leukocyte adhesion factor ICAM1, and chemokines that attract neutrophils, monocytes, and T cells. In an animal model of anti-TNF-resistant intestinal inflammation, genetic deletion or pharmacological blockade of OSM significantly attenuates colitis. Furthermore, according to an analysis of more than 200 patients with IBD, including two cohorts from phase 3 clinical trials of infliximab and golimumab, high pretreatment expression of OSM is strongly associated with failure of anti-TNF therapy. OSM is thus a potential biomarker and therapeutic target for IBD, and has particular relevance for anti-TNF-resistant patients.

Inhibition of lipopolysaccharide-induced osteoclast formation and bone resorption in vitro and in vivo by cysteine proteinase inhibitors.

Inflammation-induced bone destruction is a major treatment target in many inflammatory skeletal diseases. The aim of this study was to investigate if the cysteine proteinase inhibitors cystatin C, fungal cysteine proteinase inhibitor (E-64), and N-benzyloxycarbonyl-arginyl-leucyl-valyl-glycyl-diazomethane acetate (Z-RLVG-CHN2) can inhibit LPS-induced osteoclast formation. Mouse bone marrow macrophages (BMMs) were isolated and primed with receptor activator of NF-κB ligand (RANKL) for 24 h, followed by stimulation with LPS, with and without inhibitors. Adult mice were injected locally with LPS and then treated with E-64 and osteoclast formation assessed by the number of cathepsin K+ multinucleated cells. Cystatin C inhibited LPS-induced osteoclast formation time and concentration dependently (IC50 = 0.3 µM). The effect was associated with decreased mRNA and protein expression of tartrate-resistant acid phosphatase (TRAP) and cathepsin K and of the osteoclastogenic transcription factors c-Fos and NFATc1. LPS-induced osteoclast formation on bone slices was also inhibited by cystatin C, resulting in decreased pit formation and release of bone matrix proteins. Similar data were obtained with E-64 and Z-RLVG-CHN2 Cystatin C was internalized in BMMs stimulated by LPS but not in unstimulated BMMs. Osteoclast formation induced by LPS was dependent on TNF-α, and the 3 inhibitors abolished LPS-induced TNF superfamily 2 (gene encoding TNF-α; Tnfsf2) mRNA expression without affecting Il1b, Il6, or oncostatin M (Osm) expression. Formation of osteoclasts in the skull bones after local LPS stimulation was inhibited by E-64. It is concluded that cysteine proteinase inhibitors effectively inhibit LPS-induced osteoclast formation in vivo and in vitro by inhibition of TNF-α expression. The targeting of cysteine proteinases might represent a novel treatment modality for prevention of inflammatory bone loss.

Modification of the Fc Region of a Human Anti-oncostatin M Monoclonal Antibody for Higher Affinity to FcRn Receptor and Extension of Half-life in Cynomolgus Monkeys.

The purpose of this study was to evaluate the pharmacokinetics (PK) of anti-oncostatin M (OSM) IgG1 monoclonal antibodies, CNTO 1119 and its Fc variant (CNTO 8212), which incorporates the LS(Xtend) mutation to extend terminal half-life (T1/2 ), after a single intravenous (IV) or subcutaneous (SC) administration in cynomolgus monkeys, and to predict human PK. In study 1, single doses of CNTO 1119 and CNTO 8212 were administered IV or SC at 3 mg/kg to cynomolgus monkeys (n = 3 per group). In study 2, single doses of CNTO 8212 were administered IV at 1, 5 or 20 mg/kg, or SC at 5 mg/kg to cynomolgus monkeys (n = 5 per group). Serial blood samples were collected for assessment of serum concentrations of CNTO 1119 and/or CNTO 8212. A two-compartment population PK model with first-order elimination was utilized to simultaneously describe the serum concentrations of CNTO 1119 and CNTO 8212 over time after IV and SC administration in cynomolgus monkeys. The typical population PK parameter estimates for CNTO 1119 in cynomolgus monkeys were clearance (CL) = 2.81 mL/day/kg, volume of distribution of central compartment (V1 ) = 31.3 mL/kg, volume of distribution of peripheral compartment (V2 ) = 23.3 mL/kg, absolute bioavailability (F) = 0.84 and T1/2 = 13.4 days. In comparison, the typical population PK parameter estimates for CNTO 8212 in cynomolgus monkeys were CL = 1.41 mL/day/kg, V1 = 39.8 mL/kg, V2 = 32.6 mL/kg, F = 0.75 and T1/2 = 35.7 days. The mean CL of CNTO 8212 was ~50% lower compared with that for CNTO 1119 in cynomolgus monkeys. The overall volume of distribution (V1 +V2 ) for CNTO 8212 was about 32% larger compared with that for CNTO 1119, but generally similar to the vascular volume in cynomolgus monkeys. The T1/2 of CNTO 8212 was significantly (p < 0.05) longer by about 2.7-fold than that for CNTO 1119 in cynomolgus monkeys. Thus, the modification of the Fc portion of an anti-OSM IgG1 mAb for higher FcRn binding affinity resulted in lower systemic clearance and a longer terminal half-life in cynomolgus monkeys. CNTO 8212 demonstrated linear PK after a single IV dose (1-20 mg/kg) in cynomolgus monkeys. The predicted human PK parameters suggest that CNTO 8212 is likely to exhibit slow clearance and long terminal half-life in human beings and may likely allow less frequent dosing in the clinical setting.

Neutrophils are a major source of the epithelial barrier disrupting cytokine oncostatin M in patients with mucosal airways disease.

BACKGROUND: We have previously shown that oncostatin M (OSM) levels are increased in nasal polyps (NPs) of patients with chronic rhinosinusitis (CRS), as well as in bronchoalveolar lavage fluid, after segmental allergen challenge in allergic asthmatic patients. We also showed in vitro that physiologic levels of OSM impair barrier function in differentiated airway epithelium. OBJECTIVE: We sought to determine which hematopoietic or resident cell type or types were the source of the OSM expressed in patients with mucosal airways disease. METHODS: Paraffin-embedded NP sections were stained with fluorescence-labeled specific antibodies against OSM, GM-CSF, and hematopoietic cell-specific markers. Live cells were isolated from NPs and matched blood samples for flow cytometric analysis. Neutrophils were isolated from whole blood and cultured with the known OSM inducers GM-CSF and follistatin-like 1, and OSM levels were measured in the supernatants. Bronchial biopsy sections from control subjects, patients with moderate asthma, and patients with severe asthma were stained for OSM and neutrophil elastase. RESULTS: OSM staining was observed in NPs, showed colocalization with neutrophil elastase (n = 10), and did not colocalize with markers for eosinophils, macrophages, T cells, or B cells (n = 3-5). Flow cytometric analysis of NPs (n = 9) showed that 5.1% ± 2% of CD45+ cells were OSM+, and of the OSM+ cells, 56% ± 7% were CD16+Siglec-8-, indicating neutrophil lineage. Only 0.6 ± 0.4% of CD45+ events from matched blood samples (n = 5) were OSM+, suggesting that increased OSM levels in patients with CRS was locally stimulated and produced. A majority of OSM+ neutrophils expressed arginase 1 (72.5% ± 12%), suggesting an N2 phenotype. GM-CSF levels were increased in NPs compared with those in control tissue and were sufficient to induce OSM production (P < .001) in peripheral blood neutrophils in vitro. OSM+ neutrophils were also observed at increased levels in biopsy specimens from patients with severe asthma. Additionally, OSM protein levels were increased in induced sputum from asthmatic patients compared with that from control subjects (P < .05). CONCLUSIONS: Neutrophils are a major source of OSM-producing cells in patients with CRS and severe asthma.

Fstl1 Promotes Asthmatic Airway Remodeling by Inducing Oncostatin M.

Chronic asthma is associated with airway remodeling and decline in lung function. In this article, we show that follistatin-like 1 (Fstl1), a mediator not previously associated with asthma, is highly expressed by macrophages in the lungs of humans with severe asthma. Chronic allergen-challenged Lys-Cre(tg) /Fstl1(Δ/Δ) mice in whom Fstl1 is inactivated in macrophages/myeloid cells had significantly reduced airway remodeling and reduced levels of oncostatin M (OSM), a cytokine previously not known to be regulated by Fstl1. The importance of the Fstl1 induction of OSM to airway remodeling was demonstrated in murine studies in which administration of Fstl1 induced airway remodeling and increased OSM, whereas administration of an anti-OSM Ab blocked the effect of Fstl1 on inducing airway remodeling, eosinophilic airway inflammation, and airway hyperresponsiveness, all cardinal features of asthma. Overall, these studies demonstrate that the Fstl1/OSM pathway may be a novel pathway to inhibit airway remodeling in severe human asthma.

Oncostatin M and interleukin-31: Cytokines, receptors, signal transduction and physiology.

Oncostatin M (OSM) and interleukin-31 (IL-31) are two cytokines belonging to the IL-6 family which share a common signaling receptor subunit, the OSM receptor beta (OSMRß). Both of them are released by monocytes/macrophages, dendritic cells and T lymphocytes in inflammatory situations and upon binding to their respective receptor complexes they signal mainly via the JAK/STAT pathway. Besides sharing many biochemical properties, both display divergent physiological functions. This review summarizes aspects of cytokine transcription and biosynthesis, cytokine-receptor interactions, cross-species activities, signal transduction and physiology delineated from recent findings in genetic mouse models for both cytokines, OSM and IL-31.

Regulation of IL-17A responses in human airway smooth muscle cells by Oncostatin M.

BACKGROUND: Regulation of human airway smooth muscle cells (HASMC) by cytokines contributes to chemotactic factor levels and thus to inflammatory cell accumulation in lung diseases. Cytokines such as the gp130 family member Oncostatin M (OSM) can act synergistically with Th2 cytokines (IL-4 and IL-13) to modulate lung cells, however whether IL-17A responses by HASMC can be altered is not known. OBJECTIVE: To determine the effects of recombinant OSM, or other gp130 cytokines (LIF, IL-31, and IL-6) in regulating HASMC responses to IL-17A, assessing MCP-1/CCL2 and IL-6 expression and cell signaling pathways. METHODS: Cell responses of primary HASMC cultures were measured by the assessment of protein levels in supernatants (ELISA) and mRNA levels (qRT-PCR) in cell extracts. Activation of STAT, MAPK (p38) and Akt pathways were measured by immunoblot. Pharmacological agents were used to assess the effects of inhibition of these pathways. RESULTS: OSM but not LIF, IL-31 or IL-6 could induce detectable responses in HASMC, elevating MCP-1/CCL2, IL-6 levels and activation of STAT-1, 3, 5, p38 and Akt cell signaling pathways. OSM induced synergistic action with IL-17A enhancing MCP-1/CCL-2 and IL-6 mRNA and protein expression, but not eotaxin-1 expression, while OSM in combination with IL-4 or IL-13 synergistically induced eotaxin-1 and MCP-1/CCL2. OSM elevated steady state mRNA levels of IL-4Rα, OSMRß and gp130, but not IL-17RA or IL-17RC. Pharmacologic inhibition of STAT3 activation using Stattic down-regulated OSM, OSM/IL-4 or OSM/IL-13, and OSM/IL-17A synergistic responses of MCP-1/CCL-2 induction, whereas, inhibitors of Akt and p38 MAPK resulted in less reduction in MCP-1/CCL2 levels. IL-6 expression was more sensitive to inhibition of p38 (using SB203580) and was affected by Stattic in response to IL-17A/OSM stimulation. CONCLUSIONS: Oncostatin M can regulate HASMC responses alone or in synergy with IL-17A. OSM/IL-17A combinations enhance MCP-1/CCL2 and IL-6 but not eotaxin-1. Thus, OSM through STAT3 activation of HASMC may participate in inflammatory cell recruitment in inflammatory airway disease.

Oncostatin M promotes mucosal epithelial barrier dysfunction, and its expression is increased in patients with eosinophilic mucosal disease.

BACKGROUND: Epithelial barrier dysfunction is thought to play a role in many mucosal diseases, including asthma, chronic rhinosinusitis (CRS), and eosinophilic esophagitis. OBJECTIVE: The objective of this study was to investigate the role of oncostatin M (OSM) in epithelial barrier dysfunction in human mucosal disease. METHODS: OSM expression was measured in tissue extracts, nasal secretions, and bronchoalveolar lavage fluid. The effects of OSM stimulation on barrier function of normal human bronchial epithelial cells and nasal epithelial cells cultured at the air-liquid interface were assessed by using transepithelial electrical resistance and fluorescein isothiocyanate-dextran flux. Dual-color immunofluorescence was used to evaluate the integrity of tight junction structures in cultured epithelial cells. RESULTS: Analysis of samples from patients with CRS showed that OSM mRNA and protein levels were highly increased in nasal polyps compared with those seen in control uncinate tissue (P < .05). OSM levels were also increased in bronchoalveolar lavage fluid of allergic asthmatic patients after segmental allergen challenge and in esophageal biopsy specimens from patients with eosinophilic esophagitis. OSM stimulation of air-liquid interface cultures resulted in reduced barrier function, as measured by decreased transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran flux (P < .05). Alterations in barrier function by OSM were reversible, and the viability of epithelial cells was unaffected. OSM levels in lysates of nasal polyps and uncinate tissue positively correlated with levels of α2-macroglobulin, a marker of epithelial leak, in localized nasal secretions (r = 0.4855, P < .05). CONCLUSIONS: These results suggest that OSM might play a role in epithelial barrier dysfunction in patients with CRS and other mucosal diseases.

Stimulation of the JAK/STAT pathway by LIF and OSM in the human granulosa cell line COV434.

The development of the follicle and competent oocyte is highly coordinated, requiring interplay among several systems. These implicate endocrine, immune, and metabolic signals, intrafollicular paracrine factors from theca, mural, and cumulus granulosa cells, and the oocyte itself. Granulosa cells play a key role in their interaction. COV434 is one of the few human granulosa cell lines that can be used as an in vitro model for ovarian research. We aimed to evaluate the possible activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway by IL-6-type cytokines leukemia inhibitory factor (LIF) and oncostatin M (OSM) in COV434 cells. Expression of GP130 (glycoprotein 130), STAT3 (signal transducer and activators of transcription 3), PIAS3 (protein inhibitor of activated STAT 3), and SOCS3 (suppressor of cytokine signaling 3) genes after stimulation with LIF or OSM was assessed using RT-qPCR (real-time PCR). GP130 transcripts were significantly upregulated after incubation with LIF or OSM for 24h. Expression of the STAT3 gene was stimulated only after incubation with LIF, but not OSM. SOCS3 showed significant upregulation for all time periods and the levels of PIAS3 were initially down- and after 24h upregulated. Furthermore, the major signaling components of the JAK/STAT pathway, GP130 and STAT3, and the kinase activation patterns of STAT3, were examined at protein level. We found constitutive protein expression for GP130, STAT3, pSTAT3(ser727) and upregulation of pSTAT3(tyr705) by LIF and OSM. Our results demonstrate the activation of the JAK/STAT pathway by LIF and OSM in human granulosa cells.

Safety, tolerability, pharmacokinetics and pharmacodynamics of an anti- oncostatin M monoclonal antibody in rheumatoid arthritis: results from phase II randomized, placebo-controlled trials.

INTRODUCTION: Oncostatin M (OSM) has been implicated in the pathophysiology of rheumatoid arthritis (RA) through its effect on inflammation and joint damage. GSK315234 is a humanised anti-OSM Immunoglobulin G1 (IgG1) monoclonal antibody (mAb). This 3-part study examines the safety, tolerability and efficacy of GSK315234 in patients with active RA. METHOD: This was a 3-part (Parts A, B and C), multicenter study. Part A and Part B were randomised, double-blind, placebo-controlled, Bayesian adaptive dose finding studies to investigate the safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of single (Part A) and 3 repeat (Part B) intravenous infusions of GSK315234 in patients with active RA on a background of methotrexate (MTX). Part C was a single dose, randomised, single-blind, placebo-controlled study to assess subcutaneously administered GSK315234 to patients with active RA on a background of MTX. RESULT: The primary endpoint of the study was mean change in DAS28 at Day 28 in Part A and Day 56 in Part B and C. All patients receiving at least one dose of GSK315234 were included in safety analysis. In Part A, there were statistically significant differences in DAS28 between 3 mg/kg and placebo at Day 56, 84 and 91. There was also a statistically significant difference in DAS28 between 0.3 mg/kg, 3 mg/kg and 10 mg/kg, as compared to placebo, at Day 84. Although these changes were small and occurred late, they supported progression to Part B and C to determine the therapeutic potential of GSK315234. For Part B, no significant difference was observed between 6 mg/kg and placebo. For Part C, a statistically significant difference in DAS28 was observed at Day 40, Day 84 and Day 100 between the 500 mg subcutaneous group, as compared to placebo. No significant findings were observed at any of the time points for EULAR response criteria, ACR20, ACR50 or ACR70. An exploratory analysis of clinical, pharmacokinetic and pharmacodynamics data suggests the lack of efficacy may be due to moderate binding affinity and rapid off-rate of GSK315234 as compared to the higher affinity OSM receptor causing a protein carrier effect prolonging the half life of OSM due to accumulation of the OSM/antibody complex in the serum and synovial fluid. CONCLUSION: Our data highlighted the importance of binding affinity and off-rate effect of a mAb to fully neutralize the target and how this may influence its efficacy and potentially worsen disease activity. Using an anti-OSM mAb with high affinity should test this hypothesis and examine the potential of OSM as a therapeutic target in RA. TRIAL REGISTRATION: ClinicalTrials.gov no: NCT00674635.

A unique loop structure in oncostatin M determines binding affinity toward oncostatin M receptor and leukemia inhibitory factor receptor.

Oncostatin M (OSM) and leukemia inhibitory factor are pleiotropic cytokines that belong to the interleukin-6 (IL-6) family. These cytokines play a crucial role in diverse biological events like inflammation, neuroprotection, hematopoiesis, metabolism, and development. The family is grouped together based on structural similarities and their ability to activate the transmembrane receptor glycoprotein 130 (gp130). The common structure among these cytokines defines the spacing and the orientation of binding sites for cell surface receptors. OSM is unique in this family as it can signal using heterodimers of gp130 with either leukemia inhibitory factor receptor (LIFR) (type I) or oncostatin M receptor (OSMR) (type II). We have identified a unique helical loop on OSM between its B and C helices that is not found on other IL-6 family cytokines. This loop is located near the "FXXK" motif in active site III, which is essential for OSM's binding to both LIFR and OSMR. In this study, we show that the BC loop does not play a role in OSM's unique ability to bind OSMR. Shortening of the loop enhanced OSM's interaction with OSMR and LIFR as shown by kinetic and equilibrium binding analysis, suggesting the loop may hinder receptor interactions. As a consequence of improved binding, these structurally modified OSMs exhibited enhanced biological activity, including suppressed proliferation of A375 melanoma cells.

Decreased serum LL-37 and vitamin D3 levels in atopic dermatitis: relationship between IL-31 and oncostatin M.

BACKGROUND: Skin lesions with atopic dermatitis (AD) are associated with dysregulated expression of LL-37 and enhanced expression of IL-22, thymic stromal lymphopoietin (TSLP), IL-25, IL-31, and oncostatin M. Vitamin D3 enhances LL-37 production in keratinocytes. This study aimed to examine the serum levels of LL-37 and vitamin D3 and their regulation of cytokine production in patients with AD. METHODS: Serum levels of LL-37 and 25-hydroxyvitamin D3 were analyzed by ELISA. The effects of 1,25-dihydroxyvitamin D3 or LL-37 on cytokine production in T cells or keratinocytes were analyzed by ELISA and real-time PCR. RESULTS: Serum levels of LL-37 and 25-hydroxyvitamin D3 were decreased in patients with AD compared to normal donors and were correlated in both groups. Serum levels of LL-37 correlated with those of oncostatin M and IL-31 in normal donors and patients with AD, while 25-hydroxyvitamin D3 levels did so only in normal donors. 1,25-dihydroxyvitamin D3 increased LL-37 production in human keratinocytes and neutrophils. 1,25-dihydroxyvitamin D3 and LL-37 enhanced the oncostatin M and IL-31 production in CD3/28-stimulated T cells, but did not alter IL-25 and TSLP production in TNF-α-stimulated keratinocytes. In CD3/28-stimulated T cells, 1,25-dihydroxyvitamin D3 reduced the IL-22 production, while LL-37 enhanced it. These effects of 1,25-dihydroxyvitamin D3 and LL-37 were suppressed by vitamin D receptor antagonist and pertussis toxin, respectively. CONCLUSIONS: Systemic vitamin D3 levels are reduced in patients with AD, which may contribute to decreased systemic LL-37 levels. LL-37 may systemically potentiate the oncostatin M and IL-31 production in normal donors and patients with AD, while vitamin D3 may do so only in normal donors.

Increased serum human ß-defensin-2 levels in atopic dermatitis: relationship to IL-22 and oncostatin M.

Atopic dermatitis (AD) is associated with dysregulated expression of human ß-defensins (hBDs) and infiltration of T cells producing cytokines which regulate hBD expression. We examined serum levels of hBDs and cytokines in AD patients, the effects of cytokines on hBD production in human keratinocytes, and those of hBDs on cytokine production in human peripheral blood-derived T cells. Levels of serum hBD-2, IL-22, and oncostatin M, but not hBD-3, were higher in AD patients than in normal donors. Serum hBD-2 levels of AD patients correlated with AD scoring and IL-22 levels. IL-22 and oncostatin M enhanced hBD-2 production and signal transducer and activator of transcription 3 (STAT3) activities strongly and hBD-3 production moderately in human keratinocytes. STAT3 inhibitor suppressed IL-22 and oncostatin M-induced production of hBD-2 and hBD-3. hBD-2 strongly and hBD-3 moderately enhanced IL-22 and oncostatin M production, whereas hBD-3 strongly and hBD-2 moderately enhanced IL-31, IL-13, and IL-4 production in CD3/28-stimulated T cells. hBD-2 induced phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, and Akt, while hBD-3 induced phosphorylation of inhibitory κB kinase, p38 mitogen-activated protein kinase, and Akt in CD3/28-stimulated T cells. Inhibitors of these signals attenuated hBD-2- or hBD-3-induced production of cytokines. These results suggest that serum hBD-2 may be a biomarker of skin inflammation. IL-22 and oncostatin M may enhance hBD-2 production via STAT3 in keratinocytes, while hBD-2 may enhance IL-22 and oncostatin M production in T cells. hBD-3 may enhance T(H)2 responses.

Oncostatin M promotes STAT3 activation, VEGF production, and invasion in osteosarcoma cell lines.

BACKGROUND: We have previously demonstrated that both canine and human OSA cell lines, as well as 8 fresh canine OSA tumor samples, exhibit constitutive phosphorylation of STAT3, and that this correlates with enhanced expression of matrix metalloproteinase-2 (MMP2). While multiple signal transduction pathways can result in phosphorylation of STAT3, stimulation of the cytokine receptor gp130 through either IL-6 or Oncostatin M (OSM) is the most common mechanism through which STAT3 is activated. The purpose of this study was to evaluate the role of IL-6 and OSM stimulation on both canine and human OSA cell lines to begin to determine the role of these cytokines in the biology of OSA. METHODS: RT-PCR and Western blotting were used to interrogate the consequences of OSM and IL-6 stimulation of OSA cell lines. OSA cells were stimulated with OSM and/or hepatocyte growth factor (HGF) and the effects on MMP2 activity (gel zymography), proliferation (CyQUANT), invasion (Matrigel transwell assay), and VEGF production (Western blotting, ELISA) were assessed. The small molecule STAT3 inhibitor LLL3 was used to investigate the impact of STAT3 inhibition following OSM stimulation of OSA cells. RESULTS: Our data demonstrate that the OSM receptor (OSMR), but not IL-6 or its receptor, is expressed by all human and canine OSA cell lines and canine OSA tumor samples; additionally, OSM expression was noted in all tumor samples. Treatment of OSA cell lines with OSM induced phosphorylation of STAT3, Src, and JAK2. OSM stimulation also resulted in a dose dependent increase in MMP2 activity and VEGF expression that was markedly reduced following treatment with the small molecule STAT3 inhibitor LLL3. Lastly, OSM stimulation of OSA cell lines enhanced invasion through Matrigel, particularly in the presence of rhHGF. In contrast, both OSM and HGF stimulation of OSA cell lines did not alter their proliferative capacity. CONCLUSIONS: These data indicate OSM stimulation of human and canine OSA cells induces STAT3 activation, thereby enhancing the expression/activation of MMP2 and VEGF, ultimately promoting invasive behavior and tumor angiogenesis. As such, OSM and its receptor may represent a novel target for therapeutic intervention in OSA.

Black tea polyphenol inhibits CXCL10 production in oncostatin M-stimulated human gingival fibroblasts.

CXC chemokine ligand 10 (CXCL10) plays an important role in the infiltration of Th1 cells and thus in the exacerbation of periodontal disease. Theaflavin-3,3'-digallate (TFDG), polyphenol in black tea, has some beneficial effects but the effect of TFDG on CXCL10 production from human gingival fibroblasts (HGFs) is uncertain. In this study, we investigated the mechanisms by which TFDG may inhibit oncostatin M (OSM)-induced CXCL10 production in human gingival fibroblasts. TFDG prevented OSM-mediated CXCL10 production by HGFs in a dose dependent manner. TFDG significantly inhibited OSM-induced phosphorylation of c-Jun N terminal kinase (JNK), protein kinase B (Akt) (Ser473) that are related to CXCL10 production from OSM-stimulated HGFs. In addition, TFDG suppressed OSM receptor (OSMR) ß expression on HGFs. These data provide a novel mechanism where the black tea flavonoid, theaflavin, could provide direct benefits in periodontal disease.

IL-31 receptor (IL-31RA) knockout mice exhibit elevated responsiveness to oncostatin M.

IL-31 signals through the heterodimeric receptor IL-31RA and oncostatin M receptor (OSMR), and has been linked with the development of atopic dermatitis, a Th2 cytokine-associated disease in humans. However, recent studies of IL-31RA knockout (KO) mice have suggested that IL-31 signaling may be required to negatively regulate Th2 type responses rather than exacerbate them. Because those studies were performed on genetically modified mice, we examined whether neutralizing IL-31 with a specific mAb would give similar results to IL-31RA KO mice in two Th2 cytokine-associated immune models. We report no difference in lymphocyte Th2-type cytokine production after Ag immunization between IL-31RA KO mice, mice treated with the IL-31 mAb, or control animals. Second, we tested whether the absence of the IL-31RA subunit in IL-31RA KO mice may allow for increased pairing of the OSMR subunit with another cytokine receptor, gp130, resulting in overrepresentation of the heterodimeric receptor for OSM and increased responsiveness to OSM protein. We found that intranasal OSM challenge of IL-31RA KO mice resulted in increased IL-6 and vascular endothelial growth factor production in the lung compared with wild-type littermate control animals. Moreover, PBS-challenged IL-31RA KO mice already had increased levels of vascular endothelial growth factor, which were further increased by OSM challenge. These data imply that IL-31RA-deficient mice produce increased levels of OSM-inducible cytokines during airway sensitization and challenge, which may be the driving force behind the apparent exacerbation of Th2-type inflammatory responses previously observed in these mice.