Oncostatin M causes VEGF release from human airway smooth muscle: synergy with IL-1beta

Systemic inflammatory cytokine profiles in patients with gout during flare, intercritical and treat-to-target phases: TNFSF14 as new biomarker

INTRODUCTION

Untreated gout is characterised by monosodium urate (MSU) crystal accumulation responsible for recurrent flares that are commonly separated by asymptomatic phases. Both phases are inflammatory conditions of variable intensity. Gout flares are self-limited inflammatory reactions involving multiple mediators. This study aimed to characterise the inflammatory profiles of gout at different phases.

METHODS

Using the Olink targeted proteomics, levels of 92 inflammation-related proteins were measured in plasma samples of a prospective gout population (GOUTROS), collected at gout flare (T1), the intercritical phase (T2) and after reaching the target serum urate level under urate-lowering therapy (T3). Results were validated in an independent cohort (OLT1177-05) with plasmas collected at T1 and T2. Ex vivo and in vitro experiments were performed to assess the inflammatory properties of new biomarkers.

RESULTS

In total, 21 inflammatory new biomarkers were differentially expressed during the three time-points of gout disease. The levels of four of these proteins (interleukin 6 (IL-6), colony-stimulating factor 1, vascular endothelial growth factor A and tumour necrosis factor superfamily 14 (TNFSF14)) were increased during gout flare in an independent cohort. IL-6 and TNFSF14 had the highest fold change in expression during T1 versus T2 or T3. TNFSF14 was produced at the inflamed joint and enhanced the inflammatory response induced by lipopolysaccharide and MSU crystal stimulation. Conversely, TNFSF14 blockade reduced the inflammatory response. Additionally, single nucleotide polymorphisms of TNFSF14 affected the ability of myeloid cells to produce inflammatory cytokines.

CONCLUSION

Gout flare involves multiple inflammatory mediators that may be used as potential therapeutic targets.

Oncostatin M expression induced by bacterial triggers drives airway inflammatory and mucus secretion in severe asthma

[Figure: see text].

Oncostatin M in the Regulation of Connective Tissue Cells and Macrophages in Pulmonary Disease

Oncostatin M (OSM), as one of the gp130/IL-6 family of cytokines, interacts with receptor complexes that include the gp130 signaling molecule and OSM receptor β OSMRβ chain subunits. OSMRβ chains are expressed relatively highly across a broad array of connective tissue (CT) cells of the lung, such as fibroblasts, smooth muscle cells, and epithelial cells, thus enabling robust responses to OSM, compared to other gp130 cytokines, in the regulation of extracellular matrix (ECM) remodeling and inflammation. OSMRβ chain expression in lung monocyte/macrophage populations is low, whereas other receptor subunits, such as that for IL-6, are present, enabling responses to IL-6. OSM is produced by macrophages and neutrophils, but not CT cells, indicating a dichotomy of OSM roles in macrophage verses CT cells in lung inflammatory disease. ECM remodeling and inflammation are components of a number of chronic lung diseases that show elevated levels of OSM. OSM-induced products of CT cells, such as MCP-1, IL-6, and PGE2 can modulate macrophage function, including the expression of OSM itself, indicating feedback loops that characterize Macrophage and CT cell interaction.

STAT3 Mediates the Differential Effects of Oncostatin M and TNFα on RA Synovial Fibroblast and Endothelial Cell Function

Objectives: Oncostatin M (OSM), a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family, has been implicated in the pathogenesis of autoimmune diseases. Here we investigate the mechanisms by which its synergistic interactions with TNFα regulate the cellular bioenergetics and invasive function of synovial cells from patients with Rheumatoid Arthritis. Methods: Primary RA synovial fibroblasts (RAFLS) and human umbilical vein endothelial cells (HUVEC) were cultured with OSM alone or in combination with TNFα. Pro-inflammatory cytokines, angiogenic growth factors and adhesion molecules were quantified by real-time PCR and ELISA. Invasion, angiogenesis and cellular adhesion were quantified by Transwell invasion chambers, Matrigel tube formation assays, and adhesion binding assays. Cellular bioenergetics was assessed using the Seahorse XFe96 Analyser. Key metabolic genes (GLUT-1, HK2, PFKFB3, HIF1α, LDHA, PKM2) and transcription factor STAT3 were measured using real-time PCR and western blot. Results: OSM differentially regulates pro-inflammatory mediators in RAFLS and HUVEC, with IL-6, MCP-1, ICAM-1, and VEGF all significantly induced, in contrast to the observed inhibition of IL-8 and GROα, with opposing effects observed for VCAM-1 depending on cell type. Functionally, OSM significantly induced angiogenic network formation, adhesion, and invasive mechanisms. This was accompanied by a change in the cellular bioenergetic profile of the cells, where OSM significantly increased the ECAR/OCR ratio in favor of glycolysis, paralleled by induction of the glucose transporter GLUT-1 and key glycolytic enzymes (HK2, PFKFB3, HIF1α). OSM synergizes with TNFα to differentially regulate pro-inflammatory mechanisms in RAFLS and HUVEC. Interestingly, OSM differentially synergizes with TNFα to regulate metabolic reprogramming, where induction of glycolytic activity with concomitant attenuation of mitochondrial respiration and ATP activity was demonstrated in RAFLS but not in HUVEC. Finally, we identified a mechanism, whereby the combination of OSM with TNFα induces transcriptional activity of STAT3 only in RAFLS, with no effect observed in HUVEC. Conclusion: STAT3 mediates the differential effects of OSM and TNFα on RAFLS and EC function. Targeting OSM or downstream signaling pathways may lead to new potential therapeutic or adjuvant strategies, particularly for those patients who have sub-optimal responses to TNFi.

Coordination of Immune-Stroma Crosstalk by IL-6 Family Cytokines

Stromal cells are a subject of rapidly growing immunological interest based on their ability to influence virtually all aspects of innate and adaptive immunity. Present in every bodily tissue, stromal cells complement the functions of classical immune cells by sensing pathogens and tissue damage, coordinating leukocyte recruitment and function, and promoting immune response resolution and tissue repair. These diverse roles come with a price: like classical immune cells, inappropriate stromal cell behavior can lead to various forms of pathology, including inflammatory disease, tissue fibrosis, and cancer. An important immunological function of stromal cells is to act as information relays, responding to leukocyte-derived signals and instructing leukocyte behavior in kind. In this regard, several members of the interleukin-6 (IL-6) cytokine family, including IL-6, IL-11, oncostatin M (OSM), and leukemia inhibitory factor (LIF), have gained recognition as factors that mediate crosstalk between stromal and immune cells, with diverse roles in numerous inflammatory and homeostatic processes. This review summarizes our current understanding of how IL-6 family cytokines control stromal-immune crosstalk in health and disease, and how these interactions can be leveraged for clinical benefit.

Inhibition of H3K27me3 demethylases attenuates asthma by reversing the shift in airway smooth muscle phenotype

BACKGROUND

The shift in airway smooth muscle cells (ASMCs) phenotype between proliferation and contraction during asthma has been reported recently, highlighting a role of ASMCs plasticity in the pathophysiology of asthma. As an event involved in epigenetic post-translational modification, histone H3 lysine27 (H3K27) demethylation has attracted significant attention with respect to the epigenetic changes in diverse cells; however, little is known about its contribution to the switching of ASMCs phenotype in asthma.

OBJECTIVE

To investigate the role of trimethylated H3K27 (H3k27me3) demethylation in ASM remodelling as well as the underling mechanism.

METHODS

Mice were exposed five times a week to house dust mite (HDM) extract for 5 weeks. Lung function was measured following the final HDM challenge. Airway inflammation and remodelling were then assessed in lungs of individual mice. Human ASMCs were purchased from Sciencell Research Laboratories. Proliferation, synthesis, migration and contraction of ASMCs were analysed, respectively.

RESULTS

We observed demethylation at H3k27me3 sites in lungs harvested from mice exposed to HDM extract. Administration of a selective inhibitor of H3K27 demethylase (GSK-J4) could ameliorate the classical hallmarks of asthma, such as airway hyperresponsiveness, airway inflammation and remodelling. We established a proliferative as well as a contractive model of human ASMCs to explore the impacts of H3K27 demethylase inhibition on ASMCs phenotype. Our results indicated that GSK-J4 decreased ASMCs proliferation and migration elicited by PDGF through the Akt/JNK signalling; GSK-J4 also prevented the upregulation of contractile proteins in ASMCs induced by TGF-β through the Smad3 pathway.

CONCLUSIONS

Inhibition of H3K27me3 demethylation alleviated the development of asthmatic airway disease in vivo and modulated ASMCs phenotype in vitro. Collectively, our findings highlight a role of H3K27me3 demethylation in experimental asthma and ASMCs phenotype switch.

Pathological Roles of Neutrophil-Mediated Inflammation in Asthma and Its Potential for Therapy as a Target

Asthma is a chronic inflammatory disease that undermines the airways. It is caused by dysfunction of various types of cells, as well as cellular components, and is characterized by recruitment of inflammatory cells, bronchial hyperreactivity, mucus production, and airway remodelling and narrowing. It has commonly been considered that airway inflammation is caused by the Th2 immune response, or eosinophilia, which is a hallmark of bronchial asthma pathogenesis. Some patients display a neutrophil-dominant presentation and are characterized with low (or even absent) Th2 cytokines. In recent years, increasing evidence has also suggested that neutrophils play a key role in the development of certain subtypes of asthma. This review discusses neutrophils in asthma and potentially related targeted therapies.

STAT3 potentiates the ability of airway smooth muscle cells to promote angiogenesis by regulating VEGF signalling

NEW FINDINGS

What is the central question of this study? Airway angiogenesis occurs in asthma, and airway smooth muscle (ASM) cells have been reported to be capable of promoting airway angiogenesis. What is the potential mechanism by which ASM cells harvested from patients with asthma are capable of promoting airway angiogenesis? What is the main finding and its importance? Endogenous STAT3 mediated the pro-angiogenic ability of ASM cells by directly activating VEGF signalling. These findings contribute to the understanding of airway angiogenesis in pathology and could represent a possible therapeutic target for asthma. Airway angiogenesis indicates the specific vascular structure remodelling that occurs in asthma. Airway smooth muscle (ASM) cells have been reported to be capable of promoting airway angiogenesis; however, the potential mechanism is not yet fully defined. Herein, we investigated the role of signal transducer and activator of transcription 3 (STAT3) in the progress of airway angiogenesis. Western blot analysis showed that STAT3 activation was aberrantly upregulated in ASM tissues of patients with asthma and ASM cells that were exposed to cytokines to imitate the airway conditions in patients with asthma. Compared with the control group, both the inhibition of STAT3 activation and the silencing of endogenous STAT3 in ASM cells significantly reduced the proliferation, migration and tube-forming ability of human lung microvascular endothelial cells induced by the conditioned medium (CM) of ASM cells. The increased proliferation and migration of human aortic vascular smooth muscle cells were also repressed by inhibition of STAT3 in ASM cells. Besides, the increased activity of VEGF signalling was observed in ASM cells and the CM by RT-PCR and Western blotting assay, whereas this increased activity was reduced by STAT3 silencing. Further studies indicated that STAT3 regulated VEGF activation by directly interacting with the binding site on the 5' region of the VEGF gene. The increase in STAT3-induced pro-angiogenic activity of ASM cells was significantly decreased by administration of VEGF neutralizing antibody. In conclusion, we provided evidence that endogenous STAT3 mediates the pro-angiogenic ability of ASM cells by directly activating VEGF signalling, which could represent a possible therapeutic target for asthma.

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.

Wheezing and itching: The requirement for STAT proteins in allergic inflammation

The development of allergic inflammation requires the orchestration of gene expression from the inflamed tissue and from the infiltrating immune cells. Since many of the cytokines that promote allergic inflammation signal through hematopoietin family receptors, the Signal Transducer and Activator of Transcription (STAT) family have obligate roles in pro-allergic cytokine-induced gene regulation in multiple cell types. In this review, we summarize work defining the contribution of each of the STAT family members to the development of allergic inflammation, using data from mouse models of allergic inflammation, studies on patient samples and correlations with single nucleotide polymorphisms in STAT genes.

The enigmatic cytokine oncostatin m and roles in disease

Oncostatin M is a secreted cytokine involved in homeostasis and in diseases involving chronic inflammation. It is a member of the gp130 family of cytokines that have pleiotropic functions in differentiation, cell proliferation, and hematopoetic, immunologic, and inflammatory networks. However, Oncostatin M also has activities novel to mediators of this cytokine family and others and may have fundamental roles in mechanisms of inflammation in pathology. Studies have explored Oncostatin M functions in cancer, bone metabolism, liver regeneration, and conditions with chronic inflammation including rheumatoid arthritis, lung and skin inflammatory disease, atherosclerosis, and cardiovascular disease. This paper will review Oncostatin M biology in a historical fashion and focus on its unique activities, in vitro and in vivo, that differentiate it from other cytokines and inspire further study or consideration in therapeutic approaches.

Oncostatin M and TLR-4 ligand synergize to induce MCP-1, IL-6, and VEGF in human aortic adventitial fibroblasts and smooth muscle cells

Accumulating evidence suggests that adventitial fibroblasts play a significant role in contributing to inflammation of the arterial wall and pathogenesis of atherosclerosis. The effects of gp130 cytokines on these cells (including oncostatin M-[OSM] and IL-6), some of which have been implicated in atherosclerosis, are currently unknown. Experiments were performed to determine whether gp130 cytokines regulate human aortic adventitial fibroblasts (HAoAFs) or smooth muscle cells (HAoSMCs) alone or in context of TLR-4 ligands (also implicated in atherosclerosis). HAoAFs and HAoSMCs were stimulated with LPS and/or one of OSM, IL-6, IL-11, IL-31, or LIF. ELISAs performed on cell supernatants showed that stimulation with OSM alone caused increased MCP-1, IL-6, and VEGF levels. When combined, LPS and OSM synergized to increase MCP-1, IL-6, VEGF protein, and mRNA expression as assessed by qRT-PCR, in both HAoAFs and HAoSMCs, while LPS-induced IL-8 levels were reduced. Such effects were not observed with other gp130 cytokines. Signalling pathways including STATs, MAPKinases, and NFκB were activated, and LPS induced steady state mRNA levels of the OSM receptor chains OSMRβ and gp130. The results suggest that OSM is able to synergize with TLR-4 ligands to induce proinflammatory responses by HAoAFs and HAoSMCs, supporting the notion that OSM regulation of these cells contributes to the pathogenesis of atherosclerosis.

Otitis media impacts hundreds of mouse middle and inner ear genes

Objective

Otitis media is known to alter expression of cytokine and other genes in the mouse middle ear and inner ear. However, whole mouse genome studies of gene expression in otitis media have not previously been undertaken. Ninety-nine percent of mouse genes are shared in the human, so these studies are relevant to the human condition.

Methods

To assess inflammation-driven processes in the mouse ear, gene chip analyses were conducted on mice treated with trans-tympanic heat-killed Hemophilus influenza using untreated mice as controls. Middle and inner ear tissues were separately harvested at 6 hours, RNA extracted, and samples for each treatment processed on the Affymetrix 430 2.0 Gene Chip for expression of its 34,000 genes.

Results

Statistical analysis of gene expression compared to control mice showed significant alteration of gene expression in 2,355 genes, 11% of the genes tested and 8% of the mouse genome. Significant middle and inner ear upregulation (fold change >1.5, p<0.05) was seen in 1,081 and 599 genes respectively. Significant middle and inner ear downregulation (fold change <0.67, p<0.05) was seen in 978 and 287 genes respectively. While otitis media is widely believed to be an exclusively middle ear process with little impact on the inner ear, the inner ear changes noted in this study were numerous and discrete from the middle ear responses. This suggests that the inner ear does indeed respond to otitis media and that its response is a distinctive process. Numerous new genes, previously not studied, are found to be affected by inflammation in the ear.

Conclusion

Whole genome analysis via gene chip allows simultaneous examination of expression of hundreds of gene families influenced by inflammation in the middle ear. Discovery of new gene families affected by inflammation may lead to new approaches to the study and treatment of otitis media.

Arginase Inhibition by Ethylacetate Extract of Caesalpinia sappan Lignum Contributes to Activation of Endothelial Nitric Oxide Synthase

Caesalpinia sappan (C. sappan) is a medicinal plant used for promoting blood circulation and removing stasis. During a screening procedure on medicinal plants, the ethylacetate extract of the lignum of C. sappan (CLE) showed inhibitory activity on arginase which has recently been reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. CLE inhibited arginase II activity prepared from kidney lysate in a dose-dependent manner. In HUVECs, inhibition of arginase activity by CLE reciprocally increased NOx production through enhancement of eNOS dimer stability without any significant changes in the protein levels of eNOS and arginase II expression. Furthermore, CLE-dependent arginase inhibition resulted in increase of NO generation and decrease of superoxide production on endothelium of isolated mice aorta. These results indicate that CLE augments NO production on endothelium through inhibition of arginase activity, and may imply their usefulness for the treatment of cardiovascular diseases associated with endothelial dysfunction.

Does airway smooth muscle express an inflammatory phenotype in asthma?

In addition to hyperresponsiveness in asthma, airway smooth muscle (ASM) also manifests an inflammatory phenotype characterized by augmented expression of mediators that enhance inflammation, contribute to tissue remodelling and augment leucocyte trafficking and activity. Our present review summarizes contemporary understanding of ASM-derived mediators and their paracrine and autocrine actions in airway diseases.

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.

Oncostatin M is expressed in atherosclerotic lesions: a role for Oncostatin M in the pathogenesis of atherosclerosis

OBJECTIVE

Chronic inflammation plays a pivotal role in the development and progression of atherosclerosis. The inflammatory response is mediated by cytokines. The aim of this study was to determine if Oncostatin M (OSM), a monocyte and T-lymphocyte specific cytokine is present in atherosclerotic lesions. We also investigated the roles of signal transducer and activator of transcription (STAT)-1 and STAT-3 in regulating OSM-induced smooth muscle cell (SMC) proliferation, migration and cellular fibronectin (cFN) synthesis.

METHODS AND RESULTS

Immunostaining of atherosclerotic lesions from human carotid plaques demonstrated the expression of OSM antigen in both macrophages and SMCs. Explanted SMCs from human carotid plaques expressed OSM mRNA and protein as determined by RT-PCR and Western blotting. Using the chow-fed ApoE(-/-) mouse model of atherosclerosis, we observed that OSM was initially expressed in the intima at 20 weeks of age. By 30 weeks, OSM was expressed in both the intima and media. In vitro studies show that OSM promotes SMC proliferation, migration and cFN synthesis. Lentivirus mediated-inhibition of STAT-1 and STAT-3 prevented OSM-induced SMC proliferation, migration and cellular fibronectin synthesis.

CONCLUSIONS

These findings demonstrate that OSM is expressed in atherosclerotic lesions and may contribute to the progression of atherosclerosis by promoting SMC proliferation, migration and extracellular matrix protein synthesis through the STAT pathway.

Oncostatin M-enhanced vascular endothelial growth factor expression in human vascular smooth muscle cells involves PI3K-, p38 MAPK-, Erk1/2- and STAT1/STAT3-dependent pathways and is attenuated by interferon-γ

The pleiotropic cytokine oncostatin M (OSM), a member of the glycoprotein (gp)130 ligand family, plays a key role in inflammation and cardiovascular disease. As inflammation precedes and accompanies pathological angiogenesis, we investigated the effect of OSM and other gp130 ligands on vascular endothelial growth factor (VEGF) production in human vascular smooth muscle cells (SMC). Human coronary artery SMC (HCASMC) and human aortic SMC (HASMC) were treated with different gp130 ligands. VEGF protein was determined by ELISA. Specific mRNA was detected by RT-PCR. Western blotting was performed for signal transducers and activators of transcription1 (STAT1), STAT3, Akt and p38 mitogen-activated protein kinase (p38 MAPK). OSM mRNA and VEGF mRNA expression was analyzed in human carotid endaterectomy specimens from 15 patients. OSM increased VEGF production in both HCASMC and HASMC derived from different donors. OSM upregulated VEGF and OSM receptor-specific mRNA in these cells. STAT3 inhibitor WP1066, p38 MAPK inhibitors SB-202190 and BIRB 0796, extracellular signal-regulated kinase1/2 (Erk1/2) inhibitor U0126, and phosphatidylinositol 3-kinase (PI3K) inhibitors LY-294002 and PI-103 reduced OSM-induced VEGF synthesis. We found OSM expression in human atherosclerotic lesions where OSM mRNA correlated with VEGF mRNA expression. Interferon-γ (IFN-γ), but not IL-4 or IL-10, reduced OSM-induced VEGF production in vascular SMC. Our findings that OSM, which is present in human atherosclerotic lesions and correlates with VEGF expression, stimulates production of VEGF by human coronary artery and aortic SMC indicate that OSM could contribute to plaque angiogenesis and destabilization. IFN-γ reduced OSM-induced VEGF production by vascular SMC.

Piceatannol-3'-O-beta-D-glucopyranoside as an active component of rhubarb activates endothelial nitric oxide synthase through inhibition of arginase activity

Arginase competitively inhibits nitric oxide synthase (NOS) via use of the common substrate L-arginine. Arginase II has recently reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. Here, we demonstrate that piceatannol-3'-O-beta-D-glucopyranoside (PG), a potent component of stilbenes, inhibits the activity of arginase I and II prepared from mouse liver and kidney lysates, respectively, in a dose-dependent manner. In human umbilical vein endothelial cells, incubation of PG markedly blocked arginase activity and increased NOx production, as measured by Griess assay. The PG effect was associated with increase of eNOS dimer ratio, although the protein levels of arginase II or eNOS were not changed. Furthermore, isolated mice aortic rings treated with PG showed inhibited arginase activity that resulted in increased nitric oxide (NO) production upto 78%, as measured using 4-amino-5-methylamino-2',7'-difluorescein (DAF-FM) and a decreased superoxide anions up to 63%, as measured using dihydroethidine (DHE) in the intact endothelium. PG showed IC((50)) value of 11.22 microM and 11.06 microM against arginase I and II, respectively. PG as an arginase inhibitor, therefore, represents a novel molecule for the therapy of cardiovascular diseases derived from endothelial dysfunction and may be used for the design of pharmaceutical compounds.

The use of cytokine array to examine cytokine profiles of two human cell lines exposed to indoor dust

Human cytokine array was used to investigate the cytokine profile of U937 and KERTr after exposure to indoor dust or dust extracts. The release of MCP-1 was increased while release of IL-8 and IL-1β on U937 were decreased after exposure to indoor dust. The releases of RANTES, IL-8 and VEGF from KERTr after exposure to dust extract were increased. The results of IL-8 ELISA assay were consistent with the cytokine array. Real-time RT-PCR was performed to analyze relative changes in gene expression. The MCP-1 mRNA levels were increased after U937 exposure to 18 indoor dust samples, whereas, IL-8 and IL-1β mRNA level showed both up-regulation and down-regulation. The dose-related increase and decrease response was observed on MCP-1 and IL-8, respectively. Most indoor dust extracts increased RANTES, IL-8 and VEGF mRNA levels on KERTr. The dose-dependent response was observed on RANTES and IL-8. A significant correlation (r=0.48, p<0.05) was obtained between the total PAHs concentration in dust extracts and the induction of RANTES mRNA.

gp130 at the nexus of inflammation, autoimmunity, and cancer

Glycoprotein 130 (gp130) is a shared receptor utilized by several related cytokines, including IL-6, IL-11, IL-27, Leukemia Inhibitory Factor (LIF), Oncostatin M (OSM), Ciliary Neurotrophic Factor (CNTF), Cardiotrophin 1 (CT-1) and Cardiotrophin-like Cytokine (CLC). Gp130 plays critical roles during development and gp130-deficient mice are embryonically lethal. However, the best characterized facet of this receptor and its associated cytokines is the ability to promote or suppress inflammation. The aim of this review is to discuss the role of gp130 in promoting or preventing the development of autoimmunity and cancer, two processes that are associated with aberrant inflammatory responses.

The inflammatory mediator oncostatin M induces angiopoietin 2 expression in endothelial cells in vitro and in vivo

OBJECTIVES

Members of the glycoprotein 130 (gp130) receptor-gp130 ligand family play a role in angiogenesis in different tissues. We tested the effect of this cytokine family on the angiopoietin (Ang)-Tie system, which is involved in blood vessel maturation, stabilization, and regression.

RESULTS

Oncostatin M (OSM) increased Ang2 expression in human umbilical vein endothelial cells via Janus kinase/signal transducer and activator of transcription (JAK/STAT) and mitogen-activated protein (MAP) kinase activation. Furthermore, OSM induced Ang2 expression in macrovascular endothelial cells isolated from the human aorta and in microvascular endothelial cells isolated from human heart. Our in vivo experiments revealed that mRNA expression of Ang2 in hearts of mice injected with OSM increased significantly, and levels of OSM mRNA significantly correlated with mRNA levels of Ang2 in human hearts. In addition, OSM increased the expression of its own receptors, gp130 and OSM receptor, in endothelial cells in vitro and in mice in vivo, and levels of OSM mRNA significantly correlated with mRNA levels of gp130 and OSM receptor in human hearts.

CONCLUSION

Our data, showing the effects of OSM on the Ang-Tie system in endothelial cells, in hearts of mice, and in human heart tissue, provide yet another link between inflammation and angiogenesis.

Oncostatin M (OSM) is increased in asthma with incompletely reversible airflow obstruction

Oncostatin M, a unique member of the interleukin (IL)-6 cytokine family, is thought to be involved in airway remodeling. The expression of oncostatin M in the lower airways is unknown. The aim of this study was to measure the sputum expression of oncostatin M in patients with asthma with and without irreversible airflow obstruction. Induced sputum was collected from nonsmoking adults with stable asthma (n = 53), 31 with incomplete reversibility of airflow obstruction. Peripheral blood cells were isolated and stimulated with lipopolysaccharide in 10 participants with asthma and irreversible airflow obstruction. Oncostatin M protein levels were determined in supernatant, whereas RNA was extracted to determine Oncostatin M mRNA expression using real-time polymerase chain reaction (PCR). Oncostatin M mRNA expression and protein levels were significantly higher in the sputum of asthmatics with irreversible airflow obstruction. Sputum oncostatin M levels were highest in people with severe airflow obstruction and were localized to airway neutrophils and macrophages. Peripheral blood neutrophils released more oncostatin M when stimulated with lipopolysaccharide compared with unstimulated neutrophils. Sputum oncostatin M is increased in asthma with irreversible airflow obstruction and is present in airway neutrophils and macrophages. Oncostatin M may link airway inflammation to remodeling in asthma.

Transcriptional regulation of cytokine function in airway smooth muscle cells

The immuno-modulatory properties of airway smooth muscle have become of increasing importance in our understanding of the mechanisms underlying chronic inflammation and structural remodeling of the airway wall in asthma and chronic obstructive pulmonary disease (COPD). ASM cells respond to many cytokines, growth factors and lipid mediators to produce a wide array of immuno-modulatory molecules which may in turn orchestrate and perpetuate the disease process in asthma and COPD. Despite numerous studies of the cellular effects of cytokines on cultured ASM, few have identified intracellular signaling pathways by which cytokines modulate or induce these cellular responses. In this review we provide an overview of the transcriptional mechanisms as well as intracellular signaling pathways regulating cytokine functions in ASM cells. The recent discovery of toll-like receptors in ASM cells represents a significant development in our understanding of the immuno-modulatory capabilities of ASM cells. Thus, we also review emerging evidence of the inflammatory response to toll-like receptor activation in ASM cells.

The role of the extracellular matrix and specific growth factors in the regulation of inflammation and remodelling in asthma

Asthma is a disease characterised by persistent inflammation and structural changes in the airways, referred to as airway remodelling. The mechanisms underlying these processes may be interdependent or they may be separate processes that are driven by common factors. The levels of a variety of growth factors (including transforming growth factor beta, granulocyte macrophage colony stimulating factor, and vascular endothelial growth factor) are known to be changed in the asthmatic airway. These and other growth factors can contribute to the development and persistence of inflammation and remodelling. One of the prominent features of the structural changes of the airways is the increased deposition and alterations in the composition of the extracellular matrix proteins. These proteins include fibronectin, many different collagen types and hyaluronan. There is a dynamic relationship between the extracellular matrix proteins and the airway mesenchymal cells such that the changes in the extracellular matrix proteins can also contribute to the persistence of inflammation and the airway remodelling. This review aims to summarise the role growth factors and extracellular matrix proteins play in the regulation of inflammation and airway remodelling in the asthmatic airway.

Monocyte-dependent oncostatin M and TNF-alpha synergize to stimulate unopposed matrix metalloproteinase-1/3 secretion from human lung fibroblasts in tuberculosis

Leukocyte-derived matrix metalloproteinases (MMP) are implicated in the tissue destruction characteristic of tuberculosis (TB). The contribution of lung stromal cells to MMP activity in TB is unknown. Oncostatin M (OSM) is an important stimulus to extrapulmonary stromal MMP induction, but its role in regulation of pulmonary MMP secretion or pathophysiology of TB is unknown. We investigated OSM secretion from Mycobacterium tuberculosis (Mtb)-infected human monocytes/macrophages and the networking effects of such OSM on lung fibroblast MMP secretion. Mtb increased monocyte OSM secretion dose dependently in vitro. In vivo tuberculous granulomas immunostained positively for OSM. Further, conditioned media from Mtb-infected monocytes (CoMTb) induced monocyte OSM secretion (670 +/- 55 versus 166 +/- 14 pg/mL in controls), implicating an autocrine loop. Mtb-induced OSM secretion was prostaglandin (PG) sensitive, and required activation of surface G-protein coupled receptors. OSM induction was ERK MAP kinase dependent, p38-requiring but JNK-independent. OSM synergized with TNF-alpha, a key cytokine in TB granuloma formation, to stimulate pulmonary fibroblast MMP-1/-3 secretion, while suppressing secretion of tissue inhibitors of metalloproteinases-1/-2. In summary, Mtb infection of monocytes results in PG-dependent OSM secretion, which synergizes with TNF-alpha to drive functionally unopposed fibroblast MMP-1/-3 secretion, demonstrating a previously unrecognized role for OSM in TB.

PDGF-induced human airway smooth muscle cell proliferation requires STAT3 and the small GTPase Rac1

The signal transducers and activators of transcription (STAT) family of transcription factors regulates a variety of biological functions including cellular proliferation, transformation, apoptosis, and differentiation. We have previously determined that PDGF activates the STAT pathway in human airway smooth muscle cells (HASMC) and that the Jak and Src kinases are required for both PDGF-induced STAT activation and HASMC proliferation. As increased airway smooth muscle (ASM) volume is associated with airflow obstruction and disease severity in patients with asthma, it is important to elucidate the cellular and molecular pathways that regulate ASM accumulation. In this paper, we investigated the requirement of STAT3 for PDGF-induced HASMC proliferation. We demonstrate that knockdown of STAT3 expression in HASMC resulted in a significant decrease in mitogen-induced cellular proliferation. Additionally, PDGF-induced activation of STAT3 required the small GTP-binding protein Rac1, and Rac1 was also required for PDGF-induced HASMC proliferation. Furthermore, PDGF treatment induced STAT3 and Rac1 to physically associate and translocate to the nucleus, identifying one mechanism by which STAT3 is regulated in response to PDGF in HASMC. Finally, we determined that STAT3 expression is required for PDGF-mediated regulation of cell cycle targets cyclin D3 and p27. These data define a novel mitogenic signaling pathway in airway smooth muscle cells leading from PDGF to Rac1 and STAT3 and subsequent cell cycle gene regulation. Thus, targeting STAT3 may prove to be a novel therapeutic approach for patients with severe asthma and significant airway wall remodeling, as manifested by ASM accumulation.

Oncostatin M induces growth arrest of skeletal muscle cells in G1 phase by regulating cyclin D1 protein level

Oncostatin M (OSM), an IL-6 family cytokine, either inhibits or enhances the growth of cells depending on cell type. Here, we report that OSM inhibits proliferation of skeletal muscle cells by blocking cell cycle progression from G(1) to S phase. OSM treatment significantly reduced levels of cyclin D1 protein and phosphorylation of retinoblastoma protein (Rb) at Ser-795, a CDK4-specific phosphorylation site. The OSM-induced cyclin D1 reduction correlated with decreased amount of the cyclin D1/p27 Kip1 complex and increased amounts of the CDK2/p27 Kip1 complex, resulting in inhibition of CDK2 activity. Results obtained with lactacystin, a proteasome inhibitor, demonstrated that cyclin D1 reduction occurred through ubiquitin/proteasome proteolysis. In addition, activation of STAT3, but not STAT1, is likely to regulate OSM-induced cyclin D1 reduction. Dominant negative (DN)-STAT3 blocked OSM-induced cyclin D1 reduction, and constitutively active-STAT3 also induced cyclin D1 reduction. These results suggest that OSM arrests skeletal muscle cell growth at the G1/S checkpoint and that this response occurs by an ubiquitin/proteasome-dependent cyclin D1 protein reduction which is regulated by STAT3.

Vascular endothelial growth factor and its relationship to inflammatory mediators

Inflammation occurs in response to host injury or infection, as the result of an autoimmune disease, or in response to the development of a tumor. Although the immune system may be helpful in fighting the tumor, it may also fuel the tumorigenic process. In fact, recent data suggest a strong link between chronic inflammation, angiogenesis, and the development of cancer. For example, inflammation and scarring caused by recurring infections with Mycobacterium tuberculosis may be a cause for cancers of the lung. Inflammatory breast cancer exhibits increased angiogenesis and lymphangiogenesis and has a higher metastatic potential than noninflammatory breast cancer. Nonsteroidal anti-inflammatory drugs have been proposed as preventives for the development of colon carcinoma and ovarian cancer. Inhibition of nuclear factor-kappaB contributes to the proposed mechanism of action. Inflammatory cytokines, including interleukin-6, serve as autocrine and paracrine growth factors for several cancers, and high levels of these cytokines may correlate with a poor prognosis and increased production of angiogenic factors. The state of the art of our understanding of this critical interaction is reviewed.

Type I interleukin-1 receptor is required for pulmonary responses to subacute ozone exposure in mice

Interleukin (IL)-1, a proinflammatory cytokine, is expressed in the lung after ozone (O(3)) exposure. IL-1 mediates its effects through the type I IL-1 receptor (IL-1RI), the only signaling receptor for both IL-1alpha and IL-1beta. The purpose of this study was to determine the role of IL-1RI in pulmonary responses to O(3.) To that end, wild-type, C57BL/6 (IL-1RI(+/+)) mice and IL-1RI-deficient (IL-1RI(-/-)) mice were exposed to O(3) either subacutely (0.3 ppm for 72 h) or acutely (2 ppm for 3 h). Subacute O(3) exposure increased bronchoalveolar lavage fluid (BALF) protein, interferon-gamma-inducible protein (IP)-10, soluble tumor necrosis factor receptor 1 (sTNFR1), and neutrophils in IL-1RI(+/+) and IL-1RI(-/-) mice. With the exception of IP-10, all outcome indicators were reduced in IL-1RI(-/-) mice. Furthermore, subacute O(3) exposure increased IL-6 mRNA expression in IL-1RI(+/+), but not IL-1RI(-/-) mice. Acute (2 ppm) O(3) exposure increased BALF protein, IL-6, eotaxin, KC, macrophage inflammatory protein (MIP)-2, IP-10, monocyte chemotactic protein-1, sTNFR1, neutrophils, and epithelial cells in IL-1RI(+/+) and IL-1RI(-/-) mice. For IL-6, eotaxin, MIP-2, and sTNFR1, there were small but significant reductions of these outcome indicators in IL-1RI(-/-) versus IL-1RI(+/+) mice at 6 hours after exposure, but not at other time points, whereas other outcome indicators were unaffected by IL-1RI deficiency. These results suggest that IL-1RI is required for O(3)-induced pulmonary inflammation during subacute O(3) exposure, but plays a more minor role during acute O(3) exposure. In addition, these results suggest that the induction of IL-6 via IL-1RI may be important in mediating the effects of O(3) during subacute exposure.

Vascular endothelial growth factor is induced by the inflammatory cytokines interleukin-6 and oncostatin m in human adipose tissue in vitro and in murine adipose tissue in vivo

OBJECTIVES

It is believed that adipose tissue acts as an endocrine organ by producing inflammatory mediators and thereby contributes to the increased cardiovascular risk seen in obesity. A link between adipose tissue mass and angiogenesis has been suggested. Vascular endothelial growth factor (VEGF) seems to be implicated in this process. Members of the glycoprotein (gp)130 ligand family regulate VEGF expression in other cells.

METHODS AND RESULTS

We used tissue explants as well as primary cultures of preadipocytes and adipocytes from human subcutaneous and visceral adipose tissue to investigate whether the gp130 ligands oncostatin M (OSM), interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and cardiotrophin-1 (CT-1) regulate VEGF expression in human adipose tissue. Human subcutaneous and visceral adipose tissue responded to treatment with IL-6 and OSM with a significant increase in VEGF production. Human preadipocytes were isolated from subcutaneous and visceral adipose tissue. Adipocyte-differentiation was induced by hormone-supplementation. All cell types responded to IL-6 and OSM with a robust increase in VEGF protein production and a similar increase in VEGF-specific mRNA. Furthermore, IL-1beta synergistically enhanced the effect of OSM on VEGF production. AG-490, a JAK/STAT inhibitor, abolished the OSM-dependent VEGF induction almost completely. In mice, IL-6 and OSM increased serum levels of VEGF and VEGF mRNA and vessel density in adipose tissue.

CONCLUSION

We speculate that the inflammatory cytokines IL-6 and OSM might support angiogenesis during adipose tissue growth by upregulating VEGF.

Oncostatin M stimulates expression of stromal-derived factor-1 in human mesenchymal stem cells

Stromal-derived factor-1 (SDF-1) is a CXC chemokine that attracts leukocytes and endothelial progenitor cells. In the present study, we demonstrated that oncostatin M (OSM) stimulates expression and secretion of SDF-1 in both human adipose tissue-derived mesenchymal stem cells (hATSCs) and bone marrow-derived mesenchymal stem cells. The OSM-stimulated expression of SDF-1 in hATSCs was completely abrogated by pretreatment of the cells with U0126, an MEK-specific inhibitor, but not with AG490, a JAK2 inhibitor, or WHI-P131, a JAK3 inhibitor, suggesting that ERK, but not JAK2 and JAK3, is involved in the OSM-induced expression of SDF-1. Pretreatment of hATSCs with anti-VEGF neutralizing antibody or VEGF receptor inhibitors, SU5416 and KRN633, had no significant impact on the OSM induction of SDF-1. Furthermore, treatment of hATSCs with recombinant human VEGF165 or adenoviral overexpression of VEGF did not increase the expression of SDF-1. These results suggest that OSM induces secretion of SDF-1 through ERK-, but not VEGF-, dependent signaling pathways in mesenchymal stem cells.

Oncostatin M induces angiogenesis and cartilage degradation in rheumatoid arthritis synovial tissue and human cartilage cocultures

OBJECTIVE

To investigate the role of oncostatin M (OSM) in cell adhesion, angiogenesis, and matrix degradation in rheumatoid arthritis (RA) synovial tissue and normal human cartilage.

METHODS

Human dermal microvascular endothelial cell (HDMEC) and RA synovial fibroblast (RASF) proliferation and intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression were assessed by a bromodeoxyuridine proliferation assay and flow cytometry. HDMEC tubule formation and migration were assessed by Matrigel culture and migration assay. Production of matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinases 1 (TIMP-1) in RA synovial explants, and proteoglycan/glycosaminoglycan (GAG) release, vascular endothelial growth factor (VEGF), and angiopoietin 2 production from RASF/normal cartilage cocultures were assessed by enzyme-linked immunosorbent assay and immunohistology.

RESULTS

HDMEC/RASF proliferation was induced by OSM and interleukin-1beta (IL-1beta), alone and in combination. OSM enhanced cell surface expression of ICAM-1, but not VCAM-1, on endothelial cells and RASFs. OSM increased endothelial cell tubule formation and migration. In RA synovial explants, OSM induced production of MMP-1 and TIMP-1. When OSM was combined with IL-1beta, however, the MMP-1:TIMP-1 ratio was significantly increased. OSM potentiated IL-1beta-induced MMP-1 and MMP-13 expression in normal human cartilage/RASF cocultures, resulting in a significant increase in the MMP:TIMP ratio. In OSM/IL-1beta- stimulated cocultures, cartilage sections demonstrated significant proteoglycan depletion that was paralleled by a significant increase in GAG release in supernatants. Finally, compared with either cytokine alone, the combination of OSM and IL-1beta significantly induced VEGF production in RASF/cartilage cocultures.

CONCLUSION

These data suggest that OSM promotes angiogenesis and endothelial cell migration and potentiates the effects of IL-1beta in promoting extracellular matrix turnover and human cartilage degradation. Furthermore, the induction of VEGF in cocultures supports the hypothesis of a link between angiogenesis and cartilage degradation.

Effect of IL-6 trans-signaling on the pro-remodeling phenotype of airway smooth muscle

Increased levels of IL-6 are documented in asthma, but its contribution to the pathology is unknown. Asthma is characterized by airway wall thickening due to increased extracellular matrix deposition, inflammation, angiogenesis, and airway smooth muscle (ASM) mass. IL-6 binds to a specific membrane-bound receptor, IL-6 receptor-alpha (mIL-6Ralpha), and subsequently to the signaling protein gp130. Alternatively, IL-6 can bind to soluble IL-6 recpetor-alpha (sIL-6Ralpha) to stimulate membrane receptor-deficient cells, a process called trans-signaling. We discovered that primary human ASM cells do not express mIL-6Ralpha and, therefore, investigated the effect of IL-6 trans-signaling on the pro-remodeling phenotype of ASM. ASM required sIL-6Ralpha to activate signal transducer and activator 3, with no differences observed between cells from asthmatic subjects compared with controls. Further analysis revealed that IL-6 alone or with sIL-6Ralpha did not induce release of matrix-stimulating factors (including connective tissue growth factor, fibronectin, or integrins) and had no effect on mast cell adhesion to ASM or ASM proliferation. However, in the presence of sIL-6Ralpha, IL-6 increased eotaxin and VEGF release and may thereby contribute to local inflammation and vessel expansion in airway walls of asthmatic subjects. As levels of sIL-6Ralpha are increased in asthma, this demonstration of IL-6 trans-signaling in ASM has relevance to the development of airway remodeling.

Endothelin-1 induces hypertrophy and inhibits apoptosis in human airway smooth muscle cells

Endothelin-1 (ET-1), a G protein-coupled receptor-activating peptide, is increased in airway epithelium, plasma, and bronchoalveolar lavage fluid of asthmatic patients. We hypothesized that ET-1 may contribute to the increased airway smooth muscle mass found in severe asthma by inducing hypertrophy and inhibiting apoptosis of smooth muscle cells. To investigate this hypothesis, we determined that treatment of primary human bronchial smooth muscle cells with ET-1 dose dependently [10(-11)-10(-7) M] inhibited the apoptosis induced by serum withdrawal. ET-1 treatment also resulted in a significant increase in total protein synthesis, mediated through both ET(A) and ET(B) receptors, cell size, as well as increased expression of myosin heavy chain, alpha-smooth muscle actin, and calponin. ET-1-induced hypertrophy was accompanied by activation of JAK1/STAT-3 and MAPK1/2 (ERK1/2) cell signaling pathways. Inhibition of JAK1/STAT-3 pathways by piceatannol or ERK1/2 by the MAPK/ERK kinase 1/2 inhibitor U0126 blunted the increase in total protein synthesis. The hypertrophic effect of ET-1 was equivalent to that of the gp130 cytokine oncostatin M and greater than that induced by cardiotrophin-1. ET-1 induced release of IL-6 but not IL-11, leukemia inhibitory factor, oncostatin M, or cardiotrophin-1, although treatment of cells with IL-6 alone did not induce hypertrophy. These results suggest that ET-1 is a candidate mediator for the induction of increased smooth muscle mass in asthma and identify signaling pathways activated by this mediator.

Oncostatin M expression is functionally connected to neutrophils in the early inflammatory phase of skin repair: implications for normal and diabetes-impaired wounds

In this study, we investigated the role of the cytokine oncostatin M (OSM) for wound biology. OSM and its specific OSM receptor subunit beta (OSMRbeta) were induced upon injury. OSM induction paralleled the early influx of polymorphonuclear neutrophils (PMN) into the wound. OSM protein was localized in PMN in very early wounds, whereas OSMRbeta could be detected on macrophages, keratinocytes, and fibroblasts later in repair. To establish a functional connection between PMN and OSM expression in wounds, we depleted mice from circulating PMN by injecting an anti-PMN monoclonal antibody (Ly-6G). PMN-depleted wounds were characterized by a nearly complete loss of OSM but not OSMRbeta mRNA and protein expression within the initial 16-24 hours after injury. PMN-rich chronic wounds from diabetic ob/ob mice were characterized by a strongly elevated OSM mRNA and protein expression as compared to healthy animals. Moreover, a leptin-mediated improvement of chronic wounds in ob/ob mice was paralleled by a complete inhibition of PMN influx associated again with a dramatic loss of OSM expression at the wound site. These data constitute strong evidence that OSM expression during wound inflammation is functionally connected to PMN infiltration.

Interleukin-13 and interleukin-4 induce vascular endothelial growth factor release from airway smooth muscle cells: role of vascular endothelial growth factor genotype

Th2 cytokines induce the release of vascular endothelial growth factor (VEGF) from cultured human airway smooth muscle cells. The objective of this study was to examine the mechanistic basis for IL-4- and IL-13-induced VEGF release and to determine whether genetic differences are responsible for donor-to-donor variability in VEGF release. We measured VEGF mRNA expression by real-time PCR, mRNA stability using actinomycin D, and promoter activity with a VEGF-promoter luciferase reporter construct. We measured IL-4- and IL-13-induced VEGF release in cells from 21 donors by ELISA, genotyped the cells for common single nucleotide polymorphisms in the IL-4R alpha (Ile50Val, Ser478Pro, and Gln551Arg) and VEGF (-460T/C, -160C/T, -152G/A, +405C/G and +936 C/T) genes, and stratified the data by IL-4R alpha and VEGF genotype. IL-4 and IL-13 increased VEGF release and VEGF mRNA expression. IL-4 also increased mRNA stability but did not affect VEGF promoter activity. There was marked donor-to-donor variability in VEGF release from smooth muscle cells. The presence of Val50, Pro478/Arg551, or the Val50/Pro478/Arg551 IL-4R alpha haplotype had little effect on VEGF release. VEGF genotype at +405 or +936 alone had no effect on VEGF release, whereas cells bearing at least one -460C/-152A/+405G VEGF allele had lower release of VEGF in response to IL-13 or IL-4 than cells with other genotypes. Our data suggest that IL-4 and IL-13 mediate their effects on VEGF expression post-transcriptionally and indicate that polymorphisms in the VEGF, but not the IL-4R alpha, gene affect VEGF release from smooth muscle cells.

Beta-adrenergic receptor agonists induce the release of granulocyte chemotactic protein-2, oncostatin M, and vascular endothelial growth factor from macrophages

Vascular endothelial growth factor (VEGF), oncostatin M (OSM), and granulocyte chemotactic protein-2 (GCP-2/CXCL6) are up-regulated in U937 macrophages and peripheral blood macrophages exposed to LPS, beta-adrenergic receptor (beta2-AR) agonists (e.g. zilpaterol, and clenbuterol) and some other agents that induce intracellular cAMP (prostaglandin E2, forskolin, and butyryl cAMP). LPS in combination with beta2-agonists and cAMP elevating agents had an additional effect on the release of VEGF, OSM, and CXCL6. These proteins are up-regulated after 16-24 h of exposure and this is mediated by the beta2-AR, as determined by time course experiments and the use of a specific beta2-AR antagonist (ICI 118551). Beta2-AR agonists are used as bronchodilators in the treatment of asthma, but appear to have no effect on the chronic inflammation of the disease. However, the up-regulation of VEGF, OSM, and CXCL6 may have adverse effects on the inflammatory process of asthma. These mediators are involved in the recruitment of neutrophils, airway remodelling and angiogenesis, known features of chronic inflammatory diseases. We propose that the up-regulation of these proteins could play a role in the adverse effects of prolonged excessive usage of beta2-AR agonists on the airways besides the desensitization of the beta2-AR.