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

Mg-Cross-Linked Alginate Hydrogel Induces BMSC/Macrophage Crosstalk to Enhance Bone Tissue Regeneration via Dual Promotion of the Ligand-Receptor Pairing of the OSM/miR-370-3p-gp130 Signaling Pathway

Macrophages play a pivotal role in the crosstalk between the immune and skeletal systems, while Mg-based biomaterials demonstrate immunomodulatory capabilities in this procedure. However, the mechanism of how Mg2+ promotes osteogenesis through the interplay of bone marrow-derived mesenchymal stem cells (BMSCs) and macrophages remains undescribed. Here, we demonstrated that a Mg-cross-linked alginate hydrogel exerted a dual enhancement of BMSCs osteogenic differentiation through the ligand-receptor pairing of the OSM/miR-370-3p-gp130 axis. On the one hand, Mg2+, released from the Mg-cross-linked hydrogel, stimulates bone marrow-derived macrophages to produce and secrete more OSM. On the other hand, Mg2+ lowers the miR-370-3p level in BMSCs and in turn, reverses its suppression on gp130. Then, the OSM binds to the gp130 heterodimer receptor and activates intracellular osteogenic programs in BMSCs. Taken together, this study reveals a novel cross-talk pattern between the skeletal and immune systems under Mg2+ stimulation. This study not only brings new insights into the immunomodulatory properties of Mg-based biomaterials for orthopedic applications but also enriches the miRNA regulatory network and provides a promising target to facilitate bone regeneration in large bone defects.

BASOPHILS ACTIVATE PRURICEPTOR-LIKE VAGAL SENSORY NEURONS

Vagal sensory neurons convey sensations from internal organs along the vagus nerve to the brainstem. Pruriceptors are a subtype of neurons that transmit itch and induce pruritus. Despite extensive research on the molecular mechanisms of itch, studies focusing on pruriceptors in the vagal ganglia still need to be explored. In this study, we characterized vagal pruriceptor neurons by their responsiveness to pruritogens such as lysophosphatidic acid, β-alanine, chloroquine, and the cytokine oncostatin M. We discovered that lung-resident basophils produce oncostatin M and that its release can be induced by engagement of FcεRIα. Oncostatin M then sensitizes multiple populations of vagal sensory neurons, including Tac1+ and MrgprA3+ neurons in the jugular ganglia. Finally, we observed an increase in oncostatin M release in mice sensitized to the house dust mite Dermatophagoides pteronyssinus or to the fungal allergen Alternaria alternata, highlighting a novel mechanism through which basophils and vagal sensory neurons may communicate during type I hypersensitivity diseases such as allergic asthma.

Oncostatin M's Involvement in the Pathogenesis of Chronic Rhinosinusitis: Focus on Type 1 and 2 Inflammation

OBJECTIVES

The cytokine oncostatin M (OSM) elicits pathogenic effects involving disruption of the epithelial barrier function as a part of immunological response networks. It is unclear how these integrated cytokine signals influence inflammation and other physiological processes in the pathology of chronic rhinosinusitis (CRS). We investigated the expression and distribution of OSM and OSM receptor (OSMR) in CRS patients' sinonasal specimens, and we compared the results with a panel of inflammatory cytokine levels and clinical features.

PATIENTS AND METHODS

We classified CRS patients as eosinophilic (ECRS, n = 36) or non-eosinophilic (non-ECRS, n = 35) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis phenotypic criteria and compared their cases with those of 20 control subjects. We also examined OSM's stimulatory effects on cytokine receptor expression levels using the human bronchial epithelium cell line BEAS-2B.

RESULTS

RT-PCR showed that the OSM mRNA levels were significantly increased in the CRS patients' ethmoid sinus mucosa. The OSM mRNA levels were positively correlated with those of TNF-α, IL-1β, IL-13, and OSMR-β. In BEAS-2B cells, OSM treatment induced significant increases in the OSMRβ, IL-1R1, and IL-13Ra mRNA levels.

CONCLUSIONS

OSM is involved in the pathogenesis of CRS in both type 1 and type 2 inflammation, suggesting the OSM signaling pathway as a potential therapeutic target for modulating epithelial stromal interactions.

Mast cells disrupt the function of the esophageal epithelial barrier

Mast cells (MCs) accumulate in the epithelium of patients with eosinophilic esophagitis (EoE), an inflammatory disorder characterized by extensive esophageal eosinophilic infiltration. Esophageal barrier dysfunction plays an important role in the pathophysiology of EoE. We hypothesized that MCs contribute to the observed impaired esophageal epithelial barrier. Herein, we demonstrate that coculture of differentiated esophageal epithelial cells with immunoglobulin E-activated MCs significanly decreased epithelial resistance by 30% and increased permeability by 22% compared with non-activated MCs. These changes were associated with decreased messenger RNA expression of barrier proteins filaggrin, desmoglein-1 and involucrin, and antiprotease serine peptidase inhibitor kazal type 7. Using targeted proteomics, we detected various cytokines in coculture supernatants, most notably granulocyte-macrophage colony-stimulating factor and oncostatin M (OSM). OSM expression was increased by 12-fold in active EoE and associated with MC marker genes. Furthermore, OSM receptor-expressing esophageal epithelial cells were found in the esophageal tissue of patients with EoE, suggesting that the epithelial cells may respond to OSM. Stimulation of esophageal epithelial cells with OSM resulted in a dose-dependent decrease in barrier function and expression of filaggrin and desmoglein-1 and an increase in protease calpain-14. Taken together, these data suggest a role for MCs in decreasing esophageal epithelial barrier function in EoE, which may in part be mediated by OSM.

The clinical relevance of OSM in inflammatory diseases: a comprehensive review

Oncostatin M (OSM) is a pleiotropic cytokine involved in a variety of inflammatory responses such as wound healing, liver regeneration, and bone remodeling. As a member of the interleukin-6 (IL-6) family of cytokines, OSM binds the shared receptor gp130, recruits either OSMRβ or LIFRβ, and activates a variety of signaling pathways including the JAK/STAT, MAPK, JNK, and PI3K/AKT pathways. Since its discovery in 1986, OSM has been identified as a significant contributor to a multitude of inflammatory diseases, including arthritis, inflammatory bowel disease, lung and skin disease, cardiovascular disease, and most recently, COVID-19. Additionally, OSM has also been extensively studied in the context of several cancer types including breast, cervical, ovarian, testicular, colon and gastrointestinal, brain,lung, skin, as well as other cancers. While OSM has been recognized as a significant contributor for each of these diseases, and studies have shown OSM inhibition is effective at treating or reducing symptoms, very few therapeutics have succeeded into clinical trials, and none have yet been approved by the FDA for treatment. In this review, we outline the role OSM plays in a variety of inflammatory diseases, including cancer, and outline the previous and current strategies for developing an inhibitor for OSM signaling.

In-silico identification and prioritization of therapeutic targets of asthma

Asthma is a "common chronic disorder that affects the lungs causing variable and recurring symptoms like repeated episodes of wheezing, breathlessness, chest tightness and underlying inflammation. The interaction of these features of asthma determines the clinical manifestations and severity of asthma and the response to treatment" [cited from: National Heart, Lung, and Blood Institute. Expert Panel 3 Report. Guidelines for the Diagnosis and Management of Asthma 2007 (EPR-3). Available at: https://www.ncbi.nlm.nih.gov/books/NBK7232/ (accessed on January 3, 2023)]. As per the WHO, 262 million people were affected by asthma in 2019 that leads to 455,000 deaths ( https://www.who.int/news-room/fact-sheets/detail/asthma ). In this current study, our aim was to evaluate thousands of scientific documents and asthma associated omics datasets to identify the most crucial therapeutic target for experimental validation. We leveraged the proprietary tool Ontosight® Discover to annotate asthma associated genes and proteins. Additionally, we also collected and evaluated asthma related patient datasets through bioinformatics and machine learning based approaches to identify most suitable targets. Identified targets were further evaluated based on the various biological parameters to scrutinize their candidature for the ideal therapeutic target. We identified 7237 molecular targets from published scientific documents, 2932 targets from genomic structured databases and 7690 dysregulated genes from the transcriptomics and 560 targets from genomics mutational analysis. In total, 18,419 targets from all the desperate sources were analyzed and evaluated though our approach to identify most promising targets in asthma. Our study revealed IL-13 as one of the most important targets for asthma with approved drugs on the market currently. TNF, VEGFA and IL-18 were the other top targets identified to be explored for therapeutic benefit in asthma but need further clinical testing. HMOX1, ITGAM, DDX58, SFTPD and ADAM17 were the top novel targets identified for asthma which needs to be validated experimentally.

Evidence that oncostatin M synergizes with IL-4 signaling to induce TSLP expression in chronic rhinosinusitis with nasal polyps

BACKGROUND

Oncostatin M (OSM) may promote type 2 inflammation in chronic rhinosinusitis with nasal polyps (CRSwNP) by inducing thymic stromal lymphopoietin (TSLP).

OBJECTIVE

We sought to study the impact of OSM on TSLP synthesis and release from nasal epithelial cells (NECs).

METHODS

OSM receptors, IL-4 receptors (IL-4R), and TSLP were evaluated in mucosal tissue and primary NECs from patients with CRSwNP by quantitative PCR and immunofluorescence. Air-liquid interface-cultured NECs were stimulated with cytokines, including OSM, and quantitative PCR, ELISA, Western blot, and flow cytometry were used to assess the expression of OSM receptors, IL-4R, and TSLP.

RESULTS

Increased levels of OSM receptor β chain (OSMRβ), IL-4Rα, and TSLP were observed in nasal polyp tissues and primary epithelial cells from nasal polyps of patients with CRSwNP compared with control tissues or cells from control subjects. The level of expression of OSMRβ in tissue was correlated with levels of both IL-4Rα and TSLP. OSM stimulation of NECs increased the expression of OSMRβ and IL-4Rα. Stimulation with IL-4 plus OSM augmented the production of TSLP; the response was suppressed by a signal transducer and activator of transcription 6 inhibitor. Stimulation of NECs with IL-4 plus OSM increased the expression of proprotein convertase subtilisin/kexin 3, an enzyme that truncates and activates TSLP.

CONCLUSIONS

OSM increases the expression of IL-4Rα and synergizes with IL-4 to induce the synthesis and release of TSLP in NECs. Because the combination of IL-4 and OSM also augmented the expression of proprotein convertase subtilisin/kexin 3, these results suggest that OSM can induce both synthesis and posttranslational processing/activation of TSLP, promoting type 2 inflammation.

Hydrogen Sulfide Downregulates Oncostatin M Expression via PI3K/Akt/NF-κB Signaling Processes in Neutrophil-like Differentiated HL-60 Cells

The cytokine oncostatin M (OSM) is regarded as a critical mediator in various inflammatory responses. While the gaseous signaling molecule hydrogen sulfide (H₂S) plays a role in a variety of pathophysiological conditions, such as hypertension, inflammatory pain, osteoarthritis, ischemic stroke, oxidative stress, retinal degeneration, and inflammatory responses, the underlying mechanism of H₂S action on OSM expression in neutrophils needs to be clarified. In this work, we studied how H₂S reduces OSM expression in neutrophil-like differentiated (d)HL-60 cells. To evaluate the effects of H₂S, sodium hydrosulfide (NaHS, a donor that produces H₂S), ELISA, real-time PCR (qPCR), immunoblotting, and immunofluorescence staining were utilized. Although exposure to granulocyte-macrophage colony-stimulating factor (GM-CSF) resulted in upregulated levels of production and mRNA expression of OSM, these upregulated levels were reduced by pretreatment with NaHS in dHL-60 cells. Similarly, the same pretreatment lowered phosphorylated levels of phosphatidylinositol 3-kinase, Akt, and nuclear factor-kB that had been elevated by stimulation with GM-CSF. Overall, our results indicated that H₂S could be a therapeutic agent for inflammatory disorders via suppression of OSM.

Neutrophils as emerging protagonists and targets in chronic inflammatory diseases

INTRODUCTION

Neutrophils are the key cells of our innate immune system with a primary role in host defense. They rapidly arrive at the site of infection and display a range of effector functions including phagocytosis, degranulation, and NETosis to eliminate the invading pathogens. However, in recent years, studies focusing on neutrophil biology have revealed the highly adaptable nature and versatile functions of these cells which extend beyond host defense. Neutrophils are now referred to as powerful mediators of chronic inflammation. In several chronic inflammatory diseases, their untoward actions, such as immense infiltration, hyper-activation, dysregulation of effector functions, and extended survival, eventually contribute to disease pathogenesis. Therefore, a better understanding of neutrophils and their effector functions in prevalent chronic diseases will not only shed light on their role in disease pathogenesis but will also reveal them as novel therapeutic targets.

METHODS

We performed a computer-based online search using the databases, PubMed.gov and Clinical trials.gov for published research and review articles.

RESULTS AND CONCLUSIONS

This review provides an assessment of neutrophils and their crucial involvement in various chronic inflammatory disorders ranging from respiratory, neurodegenerative, autoimmune, and cardiovascular diseases. In addition, we also discuss the therapeutic approach for targeting neutrophils in disease settings that will pave the way forward for future research.

Oncostatin M: Risks and Benefits of a Novel Therapeutic Target for Atherosclerosis

BACKGROUND

Cardiovascular disease (CVD) is a leading cause of death worldwide. It is predicted that approximately 23.6 million people will die from CVDs annually by 2030. Therefore, there is a great need for an effective therapeutic approach to combat this disease. The European Cardiovascular Target Discovery (CarTarDis) consortium identified Oncostatin M (OSM) as a potential therapeutic target for atherosclerosis. The benefits of modulating OSM - an interleukin (IL)-6 family cytokine - have since been studied for multiple indications. However, as decades of high attrition rates have stressed, the success of a drug target is determined by the fine balance between benefits and the risk of adverse events. Safety issues should therefore not be overlooked.

OBJECTIVE

In this review, a risk/benefit analysis is performed on OSM inhibition in the context of atherosclerosis treatment. First, OSM signaling characteristics and its role in atherosclerosis are described. Next, an overview of in vitro, in vivo, and clinical findings relating to both the benefits and risks of modulating OSM in major organ systems is provided. Based on OSM's biological function and expression profile as well as drug intervention studies, safety concerns of inhibiting this target have been identified, assessed, and ranked for the target population.

CONCLUSION

While OSM may be of therapeutic value in atherosclerosis, drug development should also focus on de-risking the herein identified major safety concerns: tissue remodeling, angiogenesis, bleeding, anemia, and NMDA- and glutamate-induced neurotoxicity. Close monitoring and/or exclusion of patients with various comorbidities may be required for optimal therapeutic benefit.

Neutrophils and Asthma

Although eosinophilic inflammation is characteristic of asthma pathogenesis, neutrophilic inflammation is also marked, and eosinophils and neutrophils can coexist in some cases. Based on the proportion of sputum cell differentiation, asthma is classified into eosinophilic asthma, neutrophilic asthma, neutrophilic and eosinophilic asthma, and paucigranulocytic asthma. Classification by bronchoalveolar lavage is also performed. Eosinophilic asthma accounts for most severe asthma cases, but neutrophilic asthma or a mixture of the two types can also present a severe phenotype. Biomarkers for the diagnosis of neutrophilic asthma include sputum neutrophils, blood neutrophils, chitinase-3-like protein, and hydrogen sulfide in sputum and serum. Thymic stromal lymphoprotein (TSLP)/T-helper 17 pathways, bacterial colonization/microbiome, neutrophil extracellular traps, and activation of nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 pathways are involved in the pathophysiology of neutrophilic asthma and coexistence of obesity, gastroesophageal reflux disease, and habitual cigarette smoking have been associated with its pathogenesis. Thus, targeting neutrophilic asthma is important. Smoking cessation, neutrophil-targeting treatments, and biologics have been tested as treatments for severe asthma, but most clinical studies have not focused on neutrophilic asthma. Phosphodiesterase inhibitors, anti-TSLP antibodies, azithromycin, and anti-cholinergic agents are promising drugs for neutrophilic asthma. However, clinical research targeting neutrophilic inflammation is required to elucidate the optimal treatment.

Ursolic Acid Suppresses Oncostatin M Expression through Blockade of PI3K/Akt/NF-κB Signaling Processes in Neutrophil-like Differentiated HL-60 Cells

Cytokine oncostatin M (OSM) plays an important role in a variety of inflammatory reactions and is mainly produced in neutrophils in inflammatory diseases. While natural pentacyclic triterpenoid ursolic acid (UA) possesses a wide range of beneficial effects, such as anti-oxidant, anti-tumor, and anti-inflammatory, the regulatory processes of OSM suppression by UA in neutrophils are still poorly understood. This study was aimed at examining how UA regulates OSM expression in neutrophil-like differentiated (d)HL-60 cells. Enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and immunoblotting were employed to analyze the effects of UA. Whereas stimulation with granulocyte-macrophage colony-stimulating factor (GM-CSF) led to elevations of OSM production and mRNA expression, these elevations were lowered by treatment with UA in neutrophil-like dHL-60 cells. When the cells were exposed to GM-CSF, phosphorylated levels of phosphatidylinositol 3-kinase, Akt, and nuclear factor-kB were upregulated. However, the upregulations were diminished by treatment with UA in neutrophil-like dHL-60 cells. The results of this study proposed that UA might relieve inflammatory diseases via inhibition of OSM.

Resveratrol Downregulates Granulocyte-Macrophage Colony-Stimulating Factor-Induced Oncostatin M Production through Blocking of PI3K/Akt/NF-κB Signal Cascade in Neutrophil-like Differentiated HL-60 Cells

Oncostatin M (OSM) is essential in a wide range of inflammatory responses, and most OSM is produced by neutrophils in respiratory diseases. While resveratrol (RES) is regarded as an anti-inflammatory agent in a variety of conditions, the mechanism of OSM inhibition by RES in neutrophils remains to be elucidated. In this study, we investigated whether RES could inhibit OSM production in neutrophil-like differentiated (d)HL-60 cells. The effects of RES were measured by means of an enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blotting. Increases in production and mRNA expression of OSM resulted from the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) in neutrophil-like dHL-60 cells; however, these increases were downregulated by RES treatment. Exposure to GM-CSF led to elevations of phosphorylation of phosphatidylinositol 3-kinase (PI3K), Akt, and nuclear factor (NF)-kB. Treatment with RES induced downregulation of the phosphorylated levels of PI3K, Akt, and NF-κB in neutrophil-like dHL-60 cells. These results suggest that RES could be applicable to prevent and/or treat inflammatory disorders through blockade of OSM.

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

[Figure: see text].

Dexamethasone Attenuates Oncostatin M Production via Suppressing of PI3K/Akt/NF-κB Signaling in Neutrophil-like Differentiated HL-60 Cells

Oncostatin M (OSM) plays a role in various inflammatory reactions, and neutrophils are the main source of OSM in pulmonary diseases. However, there is no evidence showing the mechanism of OSM production in neutrophils. While dexamethasone (Dex) has been known to exert anti-inflammatory activity in various fields, the precise mechanisms of OSM downregulation by Dex in neutrophils remain to be determined. Here, we examined how OSM is produced in neutrophil-like differentiated HL-60 cells. Enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blot analysis were utilized to assess the potential of Dex. Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation resulted in OSM elevation in neutrophil-like dHL-60 cells. OSM elevation induced by GM-CSF is regulated by phosphatidylinositol 3-kinase (PI3K)/Akt/nuclear factor (NF)-kB signal cascades. GM-CSF stimulation upregulated phosphorylated levels of PI3K or Akt or NF-κB in neutrophil-like dHL-60 cells. Treatment with Dex decreased OSM levels as well as the phosphorylated levels of PI3K or Akt or NF-κB in neutrophil-like dHL-60 cells. Our findings show the potential of Dex in the treatment of inflammatory diseases via blocking of OSM.

IL-6 family cytokines in respiratory health and disease

Chronic lung diseases including asthma, chronic obstructive pulmonary disease (COPD) and lung fibrosis represent a major burden on healthcare systems with limited effective therapeutic options. Developing effective treatments for these debilitating diseases requires an understanding of how alterations at the molecular level affect lung macroscopic architecture. A common theme among these lung disorders is the presence of an underlying dysregulated immune system which can lead to sustained chronic inflammation. In this respect, several inflammatory cytokines have been implicated in the pathogenesis of lung diseases, thus leading to the notion that cytokines are attractive therapeutic targets for these disorders. In this review, we discuss and highlight the recent breakthroughs that have enhanced our understanding of the role of the interleukin (IL)-6 family of cytokines in lung homeostasis and chronic diseases including asthma, COPD, lung fibrosis and lung cancer.

Neutrophil-derived granule cargoes: paving the way for tumor growth and progression

Neutrophils are the key cells of our innate immune system mediating host defense via a range of effector functions including phagocytosis, degranulation, and NETosis. For this, they employ an arsenal of anti-microbial cargoes packed in their readily mobilizable granule subsets. Notably, the release of granule content is tightly regulated; however, under certain circumstances, their unregulated release can aggravate tissue damage and could be detrimental to the host. Several constituents of neutrophil granules have also been associated with various inflammatory diseases including cancer. In cancer setting, their excessive release may modulate tissue microenvironment which ultimately leads the way for tumor initiation, growth and metastasis. Neutrophils actively infiltrate within tumor tissues, wherein they show diverse phenotypic and functional heterogeneity. While most studies are focused at understanding the phenotypic heterogeneity of neutrophils, their functional heterogeneity, much of which is likely orchestrated by their granule cargoes, is beginning to emerge. Therefore, a better understanding of neutrophil granules and their cargoes will not only shed light on their diverse role in cancer but will also reveal them as novel therapeutic targets. This review provides an overview on existing knowledge of neutrophil granules and detailed insight into the pathological relevance of their cargoes in cancer. In addition, we also discuss the therapeutic approach for targeting neutrophils or their microenvironment in disease setting that will pave the way forward for future research.

IL-33 Mediates Lung Inflammation by the IL-6-Type Cytokine Oncostatin M

The interleukin-1 family member IL-33 participates in both innate and adaptive T helper-2 immune cell responses in models of lung disease. The IL-6-type cytokine Oncostatin M (OSM) elevates lung inflammation, Th2-skewed cytokines, alternatively activated (M2) macrophages, and eosinophils in C57Bl/6 mice in vivo. Since OSM induces IL-33 expression, we here test the IL-33 function in OSM-mediated lung inflammation using IL-33-/- mice. Adenoviral OSM (AdOSM) markedly induced IL-33 mRNA and protein levels in wild-type animals while IL-33 was undetectable in IL-33-/- animals. AdOSM treatment showed recruitment of neutrophils, eosinophils, and elevated inflammatory chemokines (KC, eotaxin-1, MIP1a, and MIP1b), Th2 cytokines (IL-4/IL-5), and arginase-1 (M2 macrophage marker) whereas these responses were markedly diminished in IL-33-/- mice. AdOSM-induced IL-33 was unaffected by IL-6-/- deficiency. AdOSM also induced IL-33R+ ILC2 cells in the lung, while IL-6 (AdIL-6) overexpression did not. Flow-sorted ILC2 responded in vitro to IL-33 (but not OSM or IL-6 stimulation). Matrix remodelling genes col3A1, MMP-13, and TIMP-1 were also decreased in IL-33-/- mice. In vitro, IL-33 upregulated expression of OSM in the RAW264.7 macrophage cell line and in bone marrow-derived macrophages. Taken together, IL-33 is a critical mediator of OSM-driven, Th2-skewed, and M2-like responses in mouse lung inflammation and contributes in part through activation of ILC2 cells.

Oncostatin M: A mysterious cytokine in cancers

Oncostatin M (OSM), as a member of the Interleukin-6 family cytokines, plays a significant role in inflammation, autoimmunity, and cancers. It is mainly secreted by T lymphocytes, neutrophils, and macrophages and was initially introduced as anti-cancer agent. However, in some cases, it promotes cancer progression. Overexpression of OSM and OSM receptor has been detected in various cancers including colon cancer, breast cancer, pancreatic cancer, myeloma, brain tumors, chronic lymphocytic leukemia, and hepatoblastoma. STAT3 is the main downstream signaling molecule of OSM, which operates the leading role in modifications of cancer cells and enhancing cell growth, invasion, survival, and all other hallmarks of cancer cells. However, due to the presence of multiple signaling pathways, it can act contradictory in some cancers. In this review, we will discuss the emerging roles of OSM in cancer and elucidate its function in tumor control or progression and finally discuss therapeutic approaches designed to manipulate this cytokine in cancer.

Targeting neutrophils in asthma: A therapeutic opportunity?

Suppression of airway inflammation with inhaled corticosteroids has been the key therapeutic approach for asthma for many years. Identification of inflammatory phenotypes in asthma has moreover led to important breakthroughs, e.g. with specific targeting of the IL-5 pathway as add-on treatment in difficult-to-treat eosinophilic asthma. However, the impact of interfering with the neutrophilic component in asthma is less documented and understood. This review provides an overview of established and recent insights with regard to the role of neutrophils in asthma, focusing on research in humans. We will describe the main drivers of neutrophilic responses in asthma, the heterogeneity in neutrophils and how they could contribute to asthma pathogenesis. Moreover we will describe findings from clinical trials, in which neutrophilic inflammation was targeted. It is clear that neutrophils are important actors in asthma development and play a role in exacerbations. However, more research is required to fully understand how modulation of neutrophil activity could lead to a significant benefit in asthma patients with airway neutrophilia.

RELMα is Induced in Airway Epithelial Cells by Oncostatin M Without Requirement of STAT6 or IL-6 in Mouse Lungs In Vivo

Resistin-like molecule alpha (RELMα) and YM-1 are secreted proteins implicated in murine models of alternatively activated macrophage (AA/M2) accumulation and Th2-skewed inflammation. Since the gp130 cytokine Oncostatin M (OSM) induces a Th2-like cytokine and AA/M2 skewed inflammation in mouse lung, we here investigated regulation of RELMα and YM-1. Transient pulmonary overexpression of OSM by Adenovirus vector (AdOSM) markedly induced RELMα and YM-1 protein expression in total lung. In situ hybridization showed that RELMα mRNA was highly induced in airway epithelial cells (AEC) and was co-expressed with CD68 mRNA in some but not all CD68+ cells in parenchyma. IL-6 overexpression (a comparator gp130 cytokine) induced RELMα, but at significantly lower levels. IL-6 (assessing IL-6^-/- mice) was not required, nor was STAT6 (IL-4/13 canonical signalling) for AdOSM-induction of RELMα in AEC. AEC responded directly to OSM in vitro as assessed by pSTAT3 activation. RELMα-deficient mice showed similar inflammatory cell infiltration and cytokine responses to wt in response to AdOSM, but showed less accumulation of CD206+ AA/M2 macrophages, reduced induction of extracellular matrix gene mRNAs for COL1A1, COL3A1, MMP13, and TIMP1, and reduced parenchymal alpha smooth muscle actin. Thus, RELMα is regulated by OSM in AEC and contributes to extracellular matrix remodelling in mouse lung.

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.

BAL Cell Gene Expression in Severe Asthma Reveals Mechanisms of Severe Disease and Influences of Medications

Rationale: Gene expression of BAL cells, which samples the cellular milieu within the lower respiratory tract, has not been well studied in severe asthma.Objectives: To identify new biomolecular mechanisms underlying severe asthma by an unbiased, detailed interrogation of global gene expression.Methods: BAL cell expression was profiled in 154 asthma and control subjects. Of these participants, 100 had accompanying airway epithelial cell gene expression. BAL cell expression profiles were related to participant (age, sex, race, and medication) and sample traits (cell proportions), and then severity-related gene expression determined by correlating transcripts and coexpression networks to lung function, emergency department visits or hospitalizations in the last year, medication use, and quality-of-life scores.Measurements and Main Results: Age, sex, race, cell proportions, and medications strongly influenced BAL cell gene expression, but leading severity-related genes could be determined by carefully identifying and accounting for these influences. A BAL cell expression network enriched for cAMP signaling components most differentiated subjects with severe asthma from other subjects. Subsequently, an in vitro cellular model showed this phenomenon was likely caused by a robust upregulation in cAMP-related expression in nonsevere and β-agonist-naive subjects given a β-agonist before cell collection. Interestingly, ELISAs performed on BAL lysates showed protein levels may partly disagree with expression changes.Conclusions: Gene expression in BAL cells is influenced by factors seldomly considered. Notably, β-agonist exposure likely had a strong and immediate impact on cellular gene expression, which may not translate to important disease mechanisms or necessarily match protein levels. Leading severity-related genes were discovered in an unbiased, system-wide analysis, revealing new targets that map to asthma susceptibility loci.

Activation of Shc1 Allows Oncostatin M to Induce RANKL and Osteoclast Formation More Effectively Than Leukemia Inhibitory Factor

Background and Purpose: The gp130 family of cytokines signals through receptors dimerizing with the gp130 subunit. Downstream signaling typically activates STAT3 but also SHP2/Ras/MAPK pathways. Oncostatin M (OSM) is a unique cytokine in this family since the receptor (OSMR) activates a non-redundant signaling pathway by recruitment of the adapter Shc1. We have studied the functional relevance of Shc1 for OSM-induced bone resorption.

Experimental Approach: Osteoblasts were stimulated with OSM and STAT3 and Shc1 activations were studied using real-time PCR and Western blots. The role of STAT3 and Shc1 for OSM-induced RANKL expression and osteoclast formation was studied by silencing their mRNA expressions. Effects of OSM were compared to those of the closely related cytokine leukemia inhibitory factor (LIF).

Key Results: OSM, but not LIF, induced the mRNA and protein expression of Shc1 and activated phosphorylation of Shc1 in the osteoblasts. Silencing of Shc1 decreased OSM-induced activation of STAT3 and RANKL expression. Silencing of STAT3 had no effect on activation of Shc1, but prevented the OSM-mediated increase of RANKL expression. Silencing of either Shc1 or STAT3 in osteoblasts decreased formation of osteoclasts in OSM-stimulated co-cultures of osteoblasts and macrophages. In agreement with these observations, OSM was a more potent and robust stimulator than LIF of RANKL formation and bone resorption in mouse calvariae and osteoclast formation in bone marrow cultures.

Conclusions and Implications: Activation of the Shc1-dependent STAT3 signaling is crucial for OSM-induced osteoclast formation. Inhibition of Shc1 is a potential mechanism to specifically inhibit OSM-induced bone resorption.

Extracellular Matrix and Fibrocyte Accumulation in BALB/c Mouse Lung upon Transient Overexpression of Oncostatin M

The accumulation of extracellular matrix in lung diseases involves numerous factors, including cytokines and chemokines that participate in cell activation in lung tissues and the circulation of fibrocytes that contribute to local fibrotic responses. The transient overexpression of the gp130 cytokine Oncostatin M can induce extracellular matrix (ECM) accumulation in mouse lungs, and here, we assess a role for IL-13 in this activity using gene deficient mice. The endotracheal administration of an adenovirus vector encoding Oncostatin M (AdOSM) caused increases in parenchymal lung collagen accumulation, neutrophil numbers, and CXCL1/KC chemokine elevation in bronchioalveolar lavage fluids. These effects were similar in IL-13-/- mice at day 7; however, the ECM matrix induced by Oncostatin M (OSM) was reduced at day 14 in the IL-13-/- mice. CD45+col1+ fibrocyte numbers were elevated at day 7 due to AdOSM whereas macrophages were not. Day 14 levels of CD45+col1+ fibrocytes were maintained in the wildtype mice treated with AdOSM but were reduced in IL-13-/- mice. The expression of the fibrocyte chemotactic factor CXCL12/SDF-1 was suppressed marginally by AdOSM in vivo and significantly in vitro in mouse lung fibroblast cell cultures. Thus, Oncostatin M can stimulate inflammation in an IL-13-independent manner in BALB/c lungs; however, the ECM remodeling and fibrocyte accumulation is reduced in IL-13 deficiency.

Fibroblast-to-myofibroblast transition in bronchial asthma

Bronchial asthma is a chronic inflammatory disease in which bronchial wall remodelling plays a significant role. This phenomenon is related to enhanced proliferation of airway smooth muscle cells, elevated extracellular matrix protein secretion and an increased number of myofibroblasts. Phenotypic fibroblast-to-myofibroblast transition represents one of the primary mechanisms by which myofibroblasts arise in fibrotic lung tissue. Fibroblast-to-myofibroblast transition requires a combination of several types of factors, the most important of which are divided into humoural and mechanical factors, as well as certain extracellular matrix proteins. Despite intensive research on the nature of this process, its underlying mechanisms during bronchial airway wall remodelling in asthma are not yet fully clarified. This review focuses on what is known about the nature of fibroblast-to-myofibroblast transition in asthma. We aim to consider possible mechanisms and conditions that may play an important role in fibroblast-to-myofibroblast transition but have not yet been discussed in this context. Recent studies have shown that some inherent and previously undescribed features of fibroblasts can also play a significant role in fibroblast-to-myofibroblast transition. Differences observed between asthmatic and non-asthmatic bronchial fibroblasts (e.g., response to transforming growth factor β, cell shape, elasticity, and protein expression profile) may have a crucial influence on this phenomenon. An accurate understanding and recognition of all factors affecting fibroblast-to-myofibroblast transition might provide an opportunity to discover efficient methods of counteracting this phenomenon.

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.

Impaired response of the bronchial epithelium to inflammation characterizes severe equine asthma

BACKGROUND

Severe equine asthma is a naturally occurring lung inflammatory disease of mature animals characterized by neutrophilic inflammation, bronchoconstriction, mucus hypersecretion and airway remodeling. Exacerbations are triggered by inhalation of dust and microbial components. Affected animals eventually are unable of aerobic performance. In this study transcriptomic differences between asthmatic and non-asthmatic animals in the response of the bronchial epithelium to an inhaled challenge were determined.

RESULTS

Paired endobronchial biopsies were obtained pre- and post-challenge from asthmatic and non-asthmatic animals. The transcriptome, determined by RNA-seq and analyzed with edgeR, contained 111 genes differentially expressed (DE) after challenge between horses with and without asthma, and 81 of these were upregulated. Genes involved in neutrophil migration and activation were in central location in interaction networks, and related gene ontology terms were significantly overrepresented. Relative abundance of specific gene products as determined by immunohistochemistry was correlated with differential gene expression. Gene sets involved in neutrophil chemotaxis, immune and inflammatory response, secretion, blood coagulation and apoptosis were overrepresented among up-regulated genes, while the rhythmic process gene set was overrepresented among down-regulated genes. MMP1, IL8, TLR4 and MMP9 appeared to be the most important proteins in connecting the STRING protein network of DE genes.

CONCLUSIONS

Several differentially expressed genes and networks in horses with asthma also contribute to human asthma, highlighting similarities between severe human adult and equine asthma. Neutrophil activation by the bronchial epithelium is suggested as the trigger of the inflammatory cascade in equine asthma, followed by epithelial injury and impaired repair and differentiation. Circadian rhythm dysregulation and the sonic Hedgehog pathway were identified as potential novel contributory factors in equine asthma.

The barrier hypothesis and Oncostatin M: Restoration of epithelial barrier function as a novel therapeutic strategy for the treatment of type 2 inflammatory disease

Mucosal epithelium maintains tissue homeostasis through many processes, including epithelial barrier function, which separates the environment from the tissue. The barrier hypothesis of type 2 inflammatory disease postulates that epithelial and epidermal barrier dysfunction, which cause inappropriate exposure to the environment, can result in allergic sensitization and development of type 2 inflammatory disease. The restoration of barrier dysfunction once it's lost, or the prevention of barrier dysfunction, have the potential to be exciting new therapeutic strategies for the treatment of type 2 inflammatory disease. Neutrophil-derived Oncostatin M has been shown to be a potent disrupter of epithelial barrier function through the induction of epithelial-mesenchymal transition (EMT). This review will discuss these events and outline several points along this axis at which therapeutic intervention could be beneficial for the treatment of type 2 inflammatory diseases.

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.

Innate Immune Cytokines, Fibroblast Phenotypes, and Regulation of Extracellular Matrix in Lung

Chronic inflammation can be caused by adaptive immune responses in autoimmune and allergic conditions, driven by a T lymphocyte subset balance (TH1, TH2, Th17, Th22, and/or Treg) and skewed cellular profiles in an antigen-specific manner. However, several chronic inflammatory diseases have no clearly defined adaptive immune mechanisms that drive chronicity. These conditions include those that affect the lung such as nonatopic asthma or idiopathic pulmonary fibrosis comprising significant health problems. The remodeling of extracellular matrix (ECM) causes organ dysfunction, and it is largely generated by fibroblasts as the major cell controlling net ECM. As such, these are potential targets of treatment approaches in the context of ECM pathology. Fibroblast phenotypes contribute to ECM and inflammatory cell accumulation, and they are integrated into chronic disease mechanisms including cancer. Evidence suggests that innate cytokine responses may be critical in nonallergic/nonautoimmune disease, and they enable environmental agent exposure mechanisms that are independent of adaptive immunity. Innate immune cytokines derived from macrophage subsets (M1/M2) and innate lymphoid cell (ILC) subsets can directly regulate fibroblast function. We also suggest that STAT3-activating gp130 cytokines can sensitize fibroblasts to the innate cytokine milieu to drive phenotypes and exacerbate existing adaptive responses. Here, we review evidence exploring innate cytokine regulation of fibroblast behavior.

Neutrophilic inflammation in asthma: mechanisms and therapeutic considerations

INTRODUCTION

Neutrophilic airway inflammation represents a pathologically distinct form of asthma and frequently appears in symptomatic adulthood asthmatics. However, clinical impacts and mechanisms of the neutrophilic inflammation have not been thoroughly evaluated up to date. Areas covered: Currently, distinct clinical manifestations, triggers, and molecular mechanisms of the neutrophilic inflammation (namely Toll-like receptor, Th1, Th17, inflammasome) are under investigation in asthma. Furthermore, possible role of the neutrophilic inflammation is being investigated in respect to the airway remodeling. We searched the related literatures published during the past 10 years on the website of Pub Med under the title of asthma and neutrophilic inflammation in human. Expert commentary: Epidemiologic and experimental studies have revealed that the neutrophilic airway inflammation is induced by a wide variety of stimuli including ozone, particulate matters, cigarette smoke, occupational irritants, endotoxins, microbial infection and colonization, and aeroallergens. These triggers provoke diverse immune and inflammatory responses leading to progressive and sometimes irreversible airway obstruction. Clinically, neutrophilic airway inflammation is frequently associated with severe asthma and poor response to glucocorticoid therapy, indicating the need for other treatment strategies. Accordingly, therapeutics will be targeted against the main mediators behind the underlying molecular mechanisms of the neutrophilic inflammation.

Regulation of IL-33 by Oncostatin M in Mouse Lung Epithelial Cells

IL-33 modulates both innate and adaptive immune responses at tissue sites including lung and may play critical roles in inflammatory lung disease. Although IL-33 expression can be altered upon NF-Kappa B activation, here we examine regulation by Oncostatin M, a gp130 cytokine family member, in mouse lung tissue. Responses were assessed in BALB/c mouse lung at day 7 of transient overexpression using endotracheally administered adenovirus encoding OSM (AdOSM) or empty vector (AdDel70). Whole lung extracts showed induction of IL-33 mRNA (>20-fold) and protein (10-fold increase in immunoblots) by AdOSM relative to AdDel70. Immunohistochemistry for IL-33 indicated a marked induction of nuclear staining in alveolar epithelial cells in vivo. Oncostatin M stimulated IL-33 mRNA and IL-33 full length protein in C10 mouse type 2 alveolar epithelial cells in culture in time-dependent and dose-dependent fashion, whereas IL-6, LIF, IL-31, IL-4, or IL-13 did not, and TGFβ repressed IL-33. IL-33 induction was associated with activation of STAT3, and pharmacological inhibition of STAT3 ameliorated IL-33 levels. These results indicate Oncostatin M as a potent inducer of IL-33 in mouse lung epithelial cells and suggest that an OSM/IL-33 axis may participate in innate immunity and inflammatory conditions in lung.

Murine Oncostatin M Acts via Leukemia Inhibitory Factor Receptor to Phosphorylate Signal Transducer and Activator of Transcription 3 (STAT3) but Not STAT1, an Effect That Protects Bone Mass

Oncostatin M (OSM) and leukemia inhibitory factor (LIF) are IL-6 family members with a wide range of biological functions. Human OSM (hOSM) and murine LIF (mLIF) act in mouse cells via a LIF receptor (LIFR)-glycoprotein 130 (gp130) heterodimer. In contrast, murine OSM (mOSM) signals mainly via an OSM receptor (OSMR)-gp130 heterodimer and binds with only very low affinity to mLIFR. hOSM and mLIF stimulate bone remodeling by both reducing osteocytic sclerostin and up-regulating the pro-osteoclastic factor receptor activator of NF-κB ligand (RANKL) in osteoblasts. In the absence of OSMR, mOSM still strongly suppressed sclerostin and stimulated bone formation but did not induce RANKL, suggesting that intracellular signaling activated by the low affinity interaction of mOSM with mLIFR is different from the downstream effects when mLIF or hOSM interacts with the same receptor. Both STAT1 and STAT3 were activated by mOSM in wild type cells or by mLIF/hOSM in wild type and Osmr^-/- cells. In contrast, in Osmr^-/- primary osteocyte-like cells stimulated with mOSM (therefore acting through mLIFR), microarray expression profiling and Western blotting analysis identified preferential phosphorylation of STAT3 and induction of its target genes but not of STAT1 and its target genes; this correlated with reduced phosphorylation of both gp130 and LIFR. In a mouse model of spontaneous osteopenia caused by hyperactivation of STAT1/3 signaling downstream of gp130 (gp130^Y757F/Y757F), STAT1 deletion rescued the osteopenic phenotype, indicating a beneficial effect of promoting STAT3 signaling over STAT1 downstream of gp130 in this low bone mass condition, and this may have therapeutic value.

Asthma and chronic obstructive pulmonary disease overlap: asthmatic chronic obstructive pulmonary disease or chronic obstructive asthma?

Asthma and chronic obstructive pulmonary disease (COPD) are different disease entities. They are both clinical diagnoses, with diagnostic tools to discriminate between one another. However, especially in older patients (>55 years) it seems more difficult to differentiate between asthma and COPD. This has led to the definition of a new phenotype called asthma COPD overlap syndrome (ACOS). However, our understanding of ACOS is at a very preliminary stage, as most research has involved subjects with existing diagnoses of asthma or COPD from studies with different definitions for ACOS. This has led to different and sometimes opposing results between studies on several features of ACOS, also depending on the comparison with COPD alone, asthma alone or both, which are summarized in this review.We suggest not using the term ACOS for a patient with features of both asthma and COPD, but to describe a patient with chronic obstructive airway disease as completely as possible, with regard to characteristics that determine treatment response (e.g. eosinophilic inflammation) and prognosis (such as smoking status, exacerbation rate, fixed airflow limitation, hyperresponsiveness, comorbidities). This will provide a far more clinically relevant diagnosis, and would aid in research on treatment in more homogenous groups of patients with chronic airways obstruction. More research is certainly needed to develop more evidence-based definitions for this patient group and to evaluate biomarkers, which will help to further classify these patients, treat them more adequately and unravel the underlying pathophysiological mechanism.

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.

RNA Seq profiling reveals a novel expression pattern of TGF-β target genes in human blood eosinophils

Despite major advances in our understanding of TGF-β signaling in multiple cell types, little is known about the direct target genes of this pathway in human eosinophils. These cells constitute the major inflammatory component present in the sputum and lung of active asthmatics and their numbers correlate well with disease severity. During the transition from acute to chronic asthma, TGF-β levels rise several fold in the lung which drives fibroblasts to produce extracellular matrix (ECM) and participate in airway and parenchymal remodeling. In this report, we use purified blood eosinophils from healthy donors and analyze baseline and TGF-β responsive genes by RNA Seq, and demonstrate that eosinophils (PBE) express 7981 protein-coding genes of which 178 genes are up-regulated and 199 genes are down-regulated by TGF-β. While 18 target genes have been previously associated with asthma and eosinophilic disorders, the vast majority have been implicated in cell death and survival, differentiation, and cellular function. Ingenuity pathway analysis revealed that 126 canonical pathways are activated by TGF-β including iNOS, TREM1, p53, IL-8 and IL-10 signaling. As TGF-β is an important cytokine for eosinophil function and survival, and pulmonary inflammation and fibrosis, our results represent a significant step toward the identification of novel TGF-β responsive genes and provide a potential therapeutic opportunity by selectively targeting relevant genes and pathways.

Asthma-COPD overlap. Clinical relevance of genomic signatures of type 2 inflammation in chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease and likely includes a subgroup that is biologically comparable to asthma. Studying asthma-associated gene expression changes in COPD could add insight into COPD pathogenesis and reveal biomarkers that predict a favorable response to corticosteroids.

OBJECTIVES

To determine whether asthma-associated gene signatures are increased in COPD and associated with asthma-related features.

METHODS

We compared disease-associated airway epithelial gene expression alterations in an asthma cohort (n = 105) and two COPD cohorts (n = 237, 171). The T helper type 2 (Th2) signature (T2S) score, a gene expression metric induced in Th2-high asthma, was evaluated in these COPD cohorts. The T2S score was correlated with asthma-related features and response to corticosteroids in COPD in a randomized, placebo-controlled trial, the Groningen and Leiden Universities study of Corticosteroids in Obstructive Lung Disease (GLUCOLD; n = 89).

MEASUREMENTS AND MAIN RESULTS

The 200 genes most differentially expressed in asthma versus healthy control subjects were enriched among genes associated with more severe airflow obstruction in these COPD cohorts (P < 0.001), suggesting significant gene expression overlap. A higher T2S score was associated with decreased lung function (P < 0.001), but not asthma history, in both COPD cohorts. Higher T2S scores correlated with increased airway wall eosinophil counts (P = 0.003), blood eosinophil percentage (P = 0.03), bronchodilator reversibility (P = 0.01), and improvement in hyperinflation after corticosteroid treatment (P = 0.019) in GLUCOLD.

CONCLUSIONS

These data identify airway gene expression alterations that can co-occur in asthma and COPD. The association of the T2S score with increased severity and "asthma-like" features (including a favorable corticosteroid response) in COPD suggests that Th2 inflammation is important in a COPD subset that cannot be identified by clinical history of asthma.

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.

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.

Neutrophils in asthma--a review

Asthma is a chronic inflammatory disease, with an array of cells involved in the pathogenesis of the disease. The role of neutrophils in the development of bronchial asthma is found to be complex, as they may trigger activation of immunocompetent cells and are a potent source of free oxygen radicals and enzymes participating in airway remodeling. The review highlights the role of neutrophils in bronchial asthma.

Systemic Inflammation in Older Adults With Asthma-COPD Overlap Syndrome

PURPOSE

The role of systemic inflammation on asthma-COPD overlap syndrome is unknown. This study aimed to examine systemic inflammation in asthma-COPD overlap syndrome, and to identify associations between clinical characteristics and inflammatory mediators in asthma-COPD overlap syndrome.

METHODS

In 108 adults older than 55 years comprising healthy controls (n=29), asthma (n=16), COPD (n=21) and asthma-COPD overlap syndrome (n=42), serum high sensitivity C-reactive protein and Interleukin 6 (IL-6) were assayed. Spirometry, induced sputum, quality of life, comorbidities and medications were assessed, and their associations with asthma-COPD overlap syndrome were analyzed using logistic regression. Associations between systemic inflammatory mediators and clinical characteristics were tested in multivariate linear regression models.

RESULTS

Patients with asthma-COPD overlap syndrome had significantly elevated IL-6 levels compared with healthy controls and asthmatics. Age, comorbidity index and IL-6 level were independently associated with asthma-COPD overlap syndrome. FEV1% predicted was inversely associated with IL-6 level, and cardiovascular disease was associated with an increased IL-6 level. Systemic markers were not associated with airway inflammation.

CONCLUSIONS

Systemic inflammation is commonly present in asthma-COPD overlap syndrome, and asthma-COPD overlap syndrome resembled COPD in terms of systemic inflammation. IL-6 is a pivotal inflammatory mediator that may be involved in airflow obstruction and cardiovascular disease and may be an independent treatment target.

Osteoimmunology: oncostatin M as a pleiotropic regulator of bone formation and resorption in health and disease

Bone remodeling in health and disease is carried out by osteoblasts and osteoclasts, which respectively produce bone matrix and resorb it. Endocrine and paracrine control of these cells can be direct, but they are also exerted indirectly, either by influencing progenitor cell differentiation or by stimulating paracrine signals from local accessory cells including osteocytes (which form a critical communication and regulation network within the bone matrix), macrophages and T lymphocytes. Here we review the osteotropic actions of the interleukin-6 family member cytokine oncostatin M (OSM), which is of particular interest because of its ability to stimulate bone accrual. OSM is produced within the bone microenvironment by cells of both mesenchymal and hematopoietic origin, including osteocytes, osteoblasts, macrophages and T lymphocytes, and can act via two receptor complexes: OSM receptor:gp130 and leukemia inhibitory factor receptor (LIFR):gp130. Although OSM can directly stimulate osteoblast mineralization activity and differentiation, it can also stimulate mesenchymal stem cell osteoblastic commitment at the expense of adipogenesis. In osteocytes, OSM can suppress the production of the bone formation inhibitor sclerostin, an action that is mediated by LIFR:gp130. OSM also stimulates the production of receptor activator of nuclear factor κB ligand by osteoblasts and thereby drives the formation of osteoclasts particularly in pathological conditions. Thus, cellular effects of OSM on bone metabolism include direct and indirect actions mediated by two related receptor/ligand complexes. OSM therefore provides an example of paracrine and endocrine control mechanisms that regulate bone mass by controlling both bone formation and resorption.

Oncostatin M modulates fibroblast function via signal transducers and activators of transcription proteins-3

Oncostatin M (OSM), an inflammatory cytokine of the interleukin-6 (IL-6) superfamily, plays a key role in various biological processes such as modulation of extracellular matrix (ECM), cell proliferation, cell survival, and induction of inflammation. It has been reported that OSM was increased in asthma and pulmonary fibrosis, and thus OSM may play a role in airway remodeling and the development of lung parenchymal fibrosis. Recruitment of lung fibroblasts to the sites of airway injury and subsequent differentiation into myofibroblasts is believed to contribute to excess ECM deposition. In the current study, we assessed the ability of OSM to modulate fibroblast collagen gel contraction, migration toward fibronectin, and expression of α-smooth muscle actin (α-SMA). We demonstrated that OSM augments gel contraction, chemotaxis, and α-SMA expression. OSM-augmented fibroblast chemotaxis was mediated by the signal transducer and activator of transcription (STAT3) and p38 mitogen-activated protein kinase, while augmentation on gel contraction and α-SMA expression was mediated by STAT3. Neither transforming growth factor-β1 nor PGE2 was involved in mediating OSM effect on the cells. The Th2 cytokines IL-4 and IL-13, which also are believed to play an important role in promoting lung fibrosis and airway remodeling, act through STAT3, and we demonstrated the potential for additive effects of OSM with IL-4 and IL-13. The present study supports the concept that OSM may contribute to tissue remodeling, which may be additive with IL-4 or IL-13. Blockade of OSM or OSM-mediated STAT3 signaling could be a therapeutic target to regulate lung fibrotic mechanisms.

Dissecting childhood asthma with nasal transcriptomics distinguishes subphenotypes of disease

BACKGROUND

Bronchial airway expression profiling has identified inflammatory subphenotypes of asthma, but the invasiveness of this technique has limited its application to childhood asthma.

OBJECTIVES

We sought to determine whether the nasal transcriptome can proxy expression changes in the lung airway transcriptome in asthmatic patients. We also sought to determine whether the nasal transcriptome can distinguish subphenotypes of asthma.

METHODS

Whole-transcriptome RNA sequencing was performed on nasal airway brushings from 10 control subjects and 10 asthmatic subjects, which were compared with established bronchial and small-airway transcriptomes. Targeted RNA sequencing nasal expression analysis was used to profile 105 genes in 50 asthmatic subjects and 50 control subjects for differential expression and clustering analyses.

RESULTS

We found 90.2% overlap in expressed genes and strong correlation in gene expression (ρ = .87) between the nasal and bronchial transcriptomes. Previously observed asthmatic bronchial differential expression was strongly correlated with asthmatic nasal differential expression (ρ = 0.77, P = 5.6 × 10(-9)). Clustering analysis identified TH2-high and TH2-low subjects differentiated by expression of 70 genes, including IL13, IL5, periostin (POSTN), calcium-activated chloride channel regulator 1 (CLCA1), and serpin peptidase inhibitor, clade B (SERPINB2). TH2-high subjects were more likely to have atopy (odds ratio, 10.3; P = 3.5 × 10(-6)), atopic asthma (odds ratio, 32.6; P = 6.9 × 10(-7)), high blood eosinophil counts (odds ratio, 9.1; P = 2.6 × 10(-6)), and rhinitis (odds ratio, 8.3; P = 4.1 × 10(-6)) compared with TH2-low subjects. Nasal IL13 expression levels were 3.9-fold higher in asthmatic participants who experienced an asthma exacerbation in the past year (P = .01). Several differentially expressed nasal genes were specific to asthma and independent of atopic status.

CONCLUSION

Nasal airway gene expression profiles largely recapitulate expression profiles in the lung airways. Nasal expression profiling can be used to identify subjects with IL13-driven asthma and a TH2-skewed systemic immune response.

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.

Pulmonary expression of oncostatin M (OSM) promotes inducible BALT formation independently of IL-6, despite a role for IL-6 in OSM-driven pulmonary inflammation

Inducible BALT (iBALT) is associated with immune responses to respiratory infections as well as with local pathology derived from chronic inflammatory lung diseases. In this study, we assessed the role of oncostatin M (OSM) in B cell activation and iBALT formation in mouse lungs. We found that C57BL/6 mice responded to an endotracheally administered adenovirus vector expressing mouse OSM, with marked iBALT formation, increased cytokine (IL-4, IL-5, IL-6, IL-10, TNF-α, and IL-12), and chemokine (CXCL13, CCL20, CCL21, eotaxin-2, KC, and MCP-1) production as well as inflammatory cell accumulation in the airways. B cells, T cells, and dendritic cells were also recruited to the lung, where many displayed an activated phenotype. Mice treated with control adenovirus vector (Addl70) were not affected. Interestingly, IL-6 was required for inflammatory responses in the airways and for the expression of most cytokines and chemokines. However, iBALT formation and lymphocyte recruitment to the lung tissue occurred independently of IL-6 and STAT6 as assessed in gene-deficient mice. Collectively, these results support the ability of OSM to induce B cell activation and iBALT formation independently of IL-6 and highlight a role for IL-6 downstream of OSM in the induction of pulmonary inflammation.