Oncostatin M (OSM) primes IL-13- and IL-4-induced eotaxin responses in fibroblasts: Regulation of the type-II IL-4 receptor chains IL-4Rα and IL-13Rα1

Oncostatin M (OSM), a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family, has been implicated in regulation of various chronic inflammatory processes. Previous work has shown that OSM induces eosinophil accumulation in mouse lungs in vivo and stimulates the eosinophil-selective chemokine eotaxin-1 synergistically with IL-4 in vitro. To examine the role of receptor regulation by OSM in synergistic eotaxin-1 responses, we here examine the modulation of the type-II IL-4 receptor (IL-4Rα and IL-13Rα1) by OSM and other gp130/IL-6 cytokine family members using NIH3T3 fibroblasts and primary mouse lung fibroblasts. We first show that OSM with either IL-13 or IL-4 synergistically induces eotaxin-1 expression in a dose-dependent fashion. Analysis of IL-4Rα expression at the protein (Western blot and FACS) and RNA (TAQMAN) levels showed that OSM markedly elevates expression by 3 h. OSM enhanced IL-13Rα1 mRNA and induced a smaller but detectable increase in total IL-13Rα1 protein. Priming fibroblasts with OSM for 6 h markedly enhanced subsequent IL-13 and IL-4-induced eotaxin-1 responses and STAT6 tyrosine-641 phosphorylation. Regulation of IL-4Rα by OSM was sensitive to inhibition of the PI3′K pathway by LY294002. These studies provide novel mechanistic insights in OSM role in regulation of synergistic eotaxin-1 responses and IL-4Rα expression in fibroblasts.     

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, OSMRβ 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.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0164-4) contains supplementary material, which is available to authorized users.     

A mouse model of airway disease: oncostatin M-induced pulmonary eosinophilia, goblet cell hyperplasia, and airway hyperresponsiveness are STAT6 dependent, and interstitial pulmonary fibrosis is STAT6 independent

Oncostatin M (OSM), a pleiotropic cytokine of the gp130 cytokine family, has been implicated in chronic allergic inflammatory and fibrotic disease states associated with tissue eosinophilia. Mouse (m)OSM induces airway eosinophilic inflammation and interstitial pulmonary fibrosis in vivo and regulates STAT6 activation in vitro. To determine the requirement of STAT6 in OSM-induced effects in vivo, we examined wild-type (WT) and STAT6-knockout (STAT6(-/-)) C57BL/6 mouse lung responses to transient ectopic overexpression of mOSM using an adenoviral vector (AdmOSM). Intratracheal AdmOSM elicited persistent eosinophilic lung inflammation that was abolished in STAT6(-/-) mice. AdmOSM also induced pronounced pulmonary remodeling characterized by goblet cell hyperplasia and parenchymal interstitial fibrosis. Goblet cell hyperplasia was STAT6 dependent; however, parenchymal interstitial fibrosis was not. OSM also induced airway hyperresponsiveness in WT mice that was abolished in STAT6(-/-) mice. OSM stimulated an inflammatory signature in the lungs of WT mice that demonstrated STAT6-dependent regulation of Th2 cytokines (IL-4, IL-13), chemokines (eotaxin-1/2, MCP-1, keratinocyte chemoattractant), and extracellular matrix modulators (tissue inhibitor of matrix metalloproteinase-1, matrix metalloproteinase-13), but STAT6-independent regulation of IL-4Rα, total lung collagen, collagen-1A1, -1A2 mRNA, and parenchymal collagen and α smooth muscle actin accumulation. Thus, overexpression of mOSM induces STAT6-dependent pulmonary eosinophilia, mucous/goblet cell hyperplasia, and airway hyperresponsiveness but STAT6-independent mechanisms of lung tissue extracellular matrix accumulation. These results also suggest that eosinophil or neutrophil accumulation in mouse lungs is not required for OSM-induced lung parenchymal collagen deposition and that OSM may have unique roles in the pathogenesis of allergic and fibrotic lung disease.     

Oncostatin M regulates eotaxin expression in fibroblasts and eosinophilic inflammation in C57BL/6 mice

Oncostatin M (OSM) is a member of the IL-6/LIF (or gp130) cytokine family, and its potential role in inflammation is supported by a number of activities identified in vitro. In this study, we investigate the action of murine OSM on expression of the CC chemokine eotaxin by fibroblasts in vitro and on mouse lung tissue in vivo. Recombinant murine OSM stimulated eotaxin protein production and mRNA levels in the NIH 3T3 fibroblast cell line. IL-6 could regulate a small induction of eotaxin in NIH 3T3 cells, but other IL-6/LIF cytokines (LIF, cardiotrophin-1 (CT-1)) had no effect. Cell signaling studies showed that murine OSM, LIF, IL-6, and CT-1 stimulated the tyrosine phosphorylation of STAT-3, suggesting STAT-3 activation is not sufficient for eotaxin induction in NIH 3T3 cells. OSM induced ERK-1,2 and p38 mitogen-activated protein kinase phosphorylation in NIH 3T3 cells, and inhibitors of ERK (PD98059) or p38 (SB203580) could partially reduce OSM-induced eotaxin production, suggesting partial dependence on mitogen-activated protein kinase signaling. OSM (but not LIF, IL-6, or CT-1) also induced eotaxin release by mouse lung fibroblast cultures derived from C57BL/6 mice. Overexpression of murine OSM in lungs of C57BL/6 mice using an adenovirus vector encoding murine OSM resulted in a vigorous inflammatory response by day 7 after intranasal administration, including marked extracellular matrix accumulation and eosinophil infiltration. Elevated levels of eotaxin mRNA in whole lung were detected at days 4 and 5. These data strongly support a role of OSM in lung inflammatory responses that involve eosinophil infiltration.     

A novel oncostatin M-inducible gene OIG37 forms a gene family with MyD118 and GADD45 and negatively regulates cell growth.

Oncostatin M (OSM) is a member of the IL-6 family cytokines that use gp130 as a common signal transducer and exhibits both growth stimulatory as well as growth inhibitory activity depending on the cells. To analyze the mechanism of OSM function, we isolated immediate early responsive genes upon OSM stimulation. Here we describe the novel OSM-inducible gene OIG37 that is related to MyD118 and GADD45. The MyD118 gene has been described as an immediate early gene induced by IL-6 in M1 monocytic cells, and GADD45 was identified as a gene induced by UV or gamma-ray irradiation. Both are considered to function in growth arrest and/or DNA repair. Although the expression of OIG37, MyD118, and GADD45 was rather ubiquitous, it was differentially regulated. As the gp130 mutant defective for activating the STAT3 pathway showed the reduced induction of OIG37 by cytokine stimulation and expression of dominant negative STAT3 inhibited the induction of OIG37 by OSM, STAT3 is involved in OIG37 induction by IL-6 family cytokines. To examine the function of OIG37, we expressed it in NIH3T3 and IL-3-dependent BaF3 cells and found that OIG37 suppressed cell growth without any evidence of apoptosis. Whereas both MyD118 and OIG37 suppressed cell growth in both cell lines, suppression by OIG37 was more efficient than by MyD118. Immunoprecipitation experiments indicated that OIG37 associates with p21, a cyclin-dependent kinase inhibitor, and proliferating cell nuclear antigen.     

Secretion of oncostatin M by infiltrating neutrophils: regulation of IL-6 and chemokine expression in human mesothelial cells

Recently, we identified that regulation of leukocyte recruitment by IL-6 requires shedding of the IL-6R from infiltrating neutrophils. In this study, experiments have examined whether other IL-6-related cytokines possess similar properties. Levels of oncostatin M (OSM) and leukemia inhibitory factor were analyzed in patients with overt bacterial peritonitis during the first 5 days of infection. Although no change in leukemia inhibitory factor was observed throughout the duration of infection, OSM was significantly elevated on day 1 and rapidly returned to baseline by days 2-3. The source of OSM was identified as the infiltrating neutrophils, and OSM levels correlated both with leukocyte numbers and i.p. soluble IL-6R (sIL-6R) levels. FACS analysis revealed that OSM receptor beta expression was restricted to human peritoneal mesothelial cells. Stimulation of human peritoneal mesothelial cells with OSM induced phosphorylation of gp130 and OSM receptor beta, which was accompanied by activation of STAT3 and secretion of CC chemokine ligand 2/monocyte chemoattractant protein-1 and IL-6. Although OSM itself did not modulate CXC chemokine ligand 8/IL-8 release, it effectively suppressed IL-1beta-mediated expression of this neutrophil-activating CXC chemokine. Moreover, OSM synergistically blocked IL-1beta-induced CXC chemokine ligand 8 secretion in combination with the IL-6/sIL-6R complex. Thus suggesting that OSM and sIL-6R release from infiltrating neutrophils may contribute to the temporal switch between neutrophil influx and mononuclear cell recruitment seen during acute inflammation.     

Receptor subunit-specific action of oncostatin M in hepatic cells and its modulation by leukemia inhibitory factor

The related cytokines, interleukin-6 (IL-6), oncostatin M (OSM), and leukemia inhibitory factor (LIF) direct the formation of specific heteromeric receptor complexes to achieve signaling. Each complex includes the common signal-transducing subunit gp130. OSM and LIF also recruit the signaling competent, but structurally distinct OSMRbeta and LIFRalpha subunits, respectively. To test the hypothesis that the particularly prominent cell regulation by OSM is due to signals contributed by OSMRbeta, we introduced stable expression of human or mouse OSMRbeta in rat hepatoma cells which have endogenous receptors for IL-6 and LIF, but not OSM. Both mouse and human OSM engaged gp130 with their respective OSMRbeta subunits, but only human OSM also acted through LIFR. Signaling by OSMRbeta-containing receptors was characterized by highest activation of STAT5 and ERK, recruitment of the insulin receptor substrate and Jun-N-terminal kinase pathways, and induction of a characteristic pattern of acute phase proteins. Since LIF together with LIFRalpha appear to form a more stable complex with gp130 than OSM with gp130 and OSMRbeta, co-activation of LIFR and OSMR resulted in a predominant LIF-like response. These results suggest that signaling by IL-6 cytokines is not identical, and that a hierarchical order of cytokine receptor action exists in which LIFR ranks as dominant member.     

Oncostatin M induces tissue-type plasminogen activator and plasminogen activator inhibitor-1 in Calu-1 lung carcinoma cells

Oncostatin M (OSM) is a glycoprotein cytokine that is produced by activated T-lymphocytes, monocytes, and macrophages. In a DNA synthesis assay, OSM reduced tritiated thymidine incorporation by 53% in Calu-1 lung carcinoma cells. Radiolabeled cDNAs from untreated Calu-1 cells and 30-h OSM-treated cells were used to probe duplicate nylon membrane cDNA expression arrays. This study revealed OSM-mediated expression of mRNAs encoding tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). Northern blot analysis showed that the steady-state level of tPA mRNA is nearly undetectable in Calu-1 cells. Exposure of these cells to OSM for 30 h increased tPA mRNA expression by 20-fold and PAI-1 mRNA expression by 5-fold. Exposure of these cells to other gp130 receptor family cytokines, including leukemia inhibitory factor (LIF), interleukin-6 (IL-6), and IL-11, do not significantly affect DNA synthesis or induction of tPA/PAI-1. Western blot studies demonstrated that OSM mediates a marked increase in secretion of the tPA protein. Secreted tPA was present in the conditioned medium almost exclusively as tPA/PAI-1 complexes. Inhibitor studies demonstrated that OSM-mediated induction of tPA and PAI-1 mRNAs is largely dependent upon activation of the MEK1/2 pathway. The JAK3/STAT3 pathway potentially serves a secondary role in these regulatory events.     

Oncostatin M receptor-mediated signal transduction is negatively regulated by SOCS3 through a receptor tyrosine-independent mechanism

Down-regulation of interleukin (IL)-6-type cytokine signaling has been shown to occur, among other mechanisms, via induction of the feedback inhibitor SOCS3 (suppressor of cytokine signaling 3). Binding of SOCS3 to the phosphorylated Tyr(759) in the cytoplasmic region of gp130, the common signal transducing receptor chain of all IL-6-type cytokines, is necessary for inhibition of Janus kinase-mediated signaling. In the present study, we analyzed the effect of SOCS3 on signal transduction by the proinflammatory cytokine oncostatin M (OSM), which signals through a receptor complex of gp130 and the OSM receptor (OSMR). OSM leads to a much stronger and prolonged induction of SOCS3 in HepG2 hepatoma cells and murine embryonal fibroblasts (MEF) compared with IL-6. A negative effect of SOCS3 on OSM signaling was confirmed using MEF cells lacking SOCS3. We can show that the OSMR-mediated signaling is inhibited by SOCS3 to a similar extent as previously described for gp130. However, the inhibition occurs independent of tyrosine motifs within the OSMR. Instead, SOCS3 interacts directly with JAK1 in a stimulation-dependent manner, a mechanism so far only known for SOCS1.     

TNF-alpha induces tyrosine phosphorylation and recruitment of the Src homology protein-tyrosine phosphatase 2 to the gp130 signal-transducing subunit of the IL-6 receptor complex

Recently, it has been demonstrated that TNF-alpha and LPS induce the expression of suppressor of cytokine signaling 3 (SOCS3) and inhibit IL-6-induced STAT3 activation in macrophages. Inhibitor studies suggested that both induction of SOCS3 and inhibition of IL-6-induced STAT3 activation depend on the activation of p38 mitogen-activated protein kinase. Since recruitment of the tyrosine phosphatase Src homology protein tyrosine phosphatase 2 (SHP2) to the signal-transducing receptor subunit gp130 attenuates IL-6-mediated STAT-activation, we were interested in whether TNF-alpha also induces the association of SHP2 to the gp130 receptor subunit. In this study we demonstrate that stimulation of macrophages and fibroblast cell lines with TNF-alpha causes the recruitment of SHP2 to the gp130 signal-transducing subunit and leads to tyrosine phosphorylation of SHP2 and gp130. In this context the cytoplasmic SHP2/SOCS3 recruitment site of gp130 tyrosine 759 is shown to be important for the inhibitory effects of TNF-alpha, since mutation of this residue completely restores IL-6-stimulated activation of STAT3 and, consequently, of a STAT3-dependent promoter. In this respect murine fibroblasts lacking exon 3 of SHP2 are not sensitive to TNF-alpha, indicating that functional SHP2 and its recruitment to gp130 are key events in inhibition of IL-6-dependent STAT activation by TNF-alpha. Furthermore, activation of p38 mitogen-activated protein kinase is shown to be essential for the inhibitory effect of TNF-alpha on IL-6 signaling and TNF-alpha-dependent recruitment of SHP2 to gp130.