Interleukin-31 and oncostatin-M mediate distinct signaling reactions and response patterns in lung epithelial cells

Emerging Concepts in Cytokine Regulation of Airway Remodeling in Asthma

Asthma, a chronic respiratory condition that has seen a dramatic rise in prevalence over the past few decades, now affects more than 300 million people globally and imposes a significant burden on healthcare systems. The key pathological features of asthma include inflammation, airway hyperresponsiveness, mucus cell metaplasia, smooth muscle hypertrophy, and subepithelial fibrosis. Cytokines released by lung epithelial cells, stromal cells, and immune cells during asthma are critical to pathological tissue remodeling in asthma. Over the past few decades, researchers have made great strides in understanding key cells involved in asthma and the cytokines that they produce. Epithelial cells as well as many adaptive and innate immune cells are activated by environmental signals to produce cytokines, namely, type 2 cytokines (IL-4, IL-5, IL-13), IFN-γ, IL-17, TGF-β, and multiple IL-6 family members. However, the precise mechanisms through which these cytokines contribute to airway remodeling remain elusive. Additionally, multiple cell types can produce the same cytokines, making it challenging to decipher how specific cell types and cytokines uniquely contribute to asthma pathogenesis. This review highlights recent advances and provides a comprehensive overview of the key cells involved in the production of cytokines and how these cytokines modulate airway remodeling in asthma.

WISIT vaccines based on IL-31-derived peptides as a novel therapeutic approach for chronic pruritic dermatoses

Vaccines are a promising therapy for the treatment of chronic conditions such as pruritus. IL-31 has been identified as an important mediator of itch. By targeting IL-31 signaling with immunotherapy, CP can be effectively alleviated. However, self-antigens such as IL-31 are highly tolerated, which has rendered conventional conjugate vaccines (CCVs) ineffective at generating sufficient antibody (Ab) responses to alleviate CP. Novel Win the Skin Immune System Trick (WISIT) vaccines however have been shown to induce substantially stronger Ab responses than CCVs in Parkinson's Disease, and so may be capable of overcoming IL-31 tolerance to effectively treat CP. In this report, WISIT vaccines presenting ten different IL-31-specific peptides were compared to CCVs presenting the same peptides. Multiple response parameters were assessed, including Ab titers induced, avidity of these Abs, and IL-31 signaling inhibition. Results demonstrated that WISIT vaccines outperform CCVs across all investigated metrics, culminating in the identification of 3 promising candidate WISIT vaccines to be taken forward for further clinical development. This report thus provides evidence that the improved immunogenicity of WISIT vaccines is not disease-specific and that WISIT vaccines may also be translated to treat dermatological disorders. Further preclinical development will be necessary to prepare the identified IL-31 targeting WISIT vaccine candidates for clinical testing.

The role of interleukin-6 family cytokines in cancer cachexia

Cachexia is a wasting syndrome that manifests in more than half of all cancer patients. Cancer-associated cachexia negatively influences the survival of patients and their quality of life. It is characterized by a rapid loss of adipose and skeletal muscle tissues, which is partly mediated by inflammatory cytokines. Here, we explored the crucial roles of interleukin-6 (IL-6) family cytokines, including IL-6, leukemia inhibitory factor, and oncostatin M, in the development of cancer cachexia. These cytokines have been shown to exacerbate cachexia by promoting the wasting of adipose and muscle tissues, activating mechanisms that enhance lipolysis and proteolysis. Overlapping effects of the IL-6 family cytokines depend on janus kinase/signal transducer and activator of transcription 3 signaling. We argue that the blockade of these cytokine pathways individually may fail due to redundancy and future therapeutic approaches should target common downstream elements to yield effective clinical outcomes.

Suppression of gp130 attenuated insulin-mediated signaling and glucose uptake in skeletal muscle cells

The aim of the present study was to investigate the effects of Oncostatin M receptor (OSMR) subunit gp130 knockdown on insulin-stimulated glucose metabolism-related signaling pathways and glucose uptake in skeletal muscle cells. siRNA-mediated gp130 knockdown was conducted in C2C12 muscle cells, and insulin was added and incubated for 1 h. The cells were cultivated to analyze the mRNA levels of gp130, phosphorylation of STAT3, and glucose metabolism-regulated signaling pathways, and OSM levels in the culture medium were analyzed. The phosphorylation of STAT 3 was significantly decreased in gp130-/- cell. The insulin stimulation was significantly increased in both gp130-/- and gp130+/+ and the phosphorylation of IRS-1 Ser 1101 was significantly decreased in gp130-/-. PI3-kinase activity and Akt Thr 308 phosphorylation were significantly decreased in gp130-/-. The insulin-stimulated increase in glucose uptake rate was significantly attenuated in gp130-/-. In the culture medium, OSM levels were significantly lower in gp130+/+compared to gp130-/- cell. In conclusion, the knockdown of gp130 caused a decrease in STAT 3 phosphorylation and resulted in the attenuation of insulin-mediated glucose metabolism signaling in skeletal muscle cells. Thus, an excessive increase in extracellular OSM may induce blunted insulin action in skeletal muscle cells.

Vitamin D Level and Immune Modulation in Children with Recurrent Wheezing

INTRODUCTION AND AIM

A direct causal relationship between vitamin D (vit D) deficiency and recurrent wheezing has not been proven. The present study investigated the role of vit D in enhancing the risk of asthma or recurrent wheezing by modifying the intensity of the inflammatory process.

MATERIAL AND METHOD

Forty children with wheezing presenting at the emergency service and sixteen healthy control subjects were included in the study. Children with wheezing were either in the first episode (20) or with recurrent wheezing (20). Children with chronic diseases, and other conditions that present with acute wheezing or that might influence the vit D level, were excluded. Blood samples were taken at presentation and 3-6 months later, to evaluate the serum levels of total IgE, vit D, IL-10 and IL-31. Statistical analysis was performed using the SPSS 25 program, with a significance level of p < 0.05.

RESULTS AND CONCLUSION

The vit D level was lower in patients with recurrent wheezing compared with those with a single episode and with the control group, and this increased with time. IL-10 was significantly higher in children with wheezing than in the control group, with the highest values in those with an acute episode of wheezing. IL-31 was higher in children with recurrent wheezing than in those with a first episode only at the initial point, while at the final time point it was lower. Low levels of vit D appear to be detected more frequently in recurrent wheezing than in simple wheezing. Immune modulation, as measured by Th2 status reflected by IL-10 and IL-31 levels, appears to depend on the wheezing phenotype and on the general health status.

Blockade of OSMRβ signaling ameliorates skin lesions in a mouse model of human atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by severe pruritus and eczematous skin lesions. Although IL-31, a type 2 helper T (Th2)-derived cytokine, is important to the development of pruritus and skin lesions in AD, the blockade of IL-31 signaling does not improve the skin lesions in AD. Oncostatin M (OSM), a member of IL-6 family of cytokines, plays important roles in the regulation of various inflammatory responses through OSM receptor β subunit (OSMRβ), a common receptor subunit for OSM and IL-31. However, the effects of OSM on the pathogenesis of AD remain to be elucidated. When AD model mice were treated with OSM, skin lesions were exacerbated and IL-4 production was increased in the lymph nodes. Next, we investigated the effects of the monoclonal antibody (mAb) against OSMRβ on the pathogenesis of AD. Treatment with the anti-OSMRβ mAb (7D2) reduced skin severity score in AD model mice. In addition to skin lesions, scratching behavior was decreased by 7D2 mAb with the reduction in the number of OSMRβ-positive neurons in the dorsal root ganglia of AD model mice. 7D2 mAb also reduced the serum concentration of IL-4, IL-13, and IgE as well as the gene expressions of IL-4 and IL-13 in the lymph nodes of AD model mice. Blockade of both IL-31 and OSM signaling is suggested to suppress both pruritus and Th2 responses, resulting in the improvement of skin lesions in AD. The anti-OSMRβ mAb may be a new therapeutic candidate for the treatment of AD.

Interleukin 31 receptor α promotes smooth muscle cell contraction and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Multiple cytokines, including IFNγ, IL-4, and IL-13 are associated with asthma; however, the mechanisms underlying the effects of these cytokines remain unclear. Here, we report a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31, in mouse models of allergic asthma. In support of this, IFNγ, IL-4, and IL-13 upregulated IL-31RA but not IL-31 in both human and mice primary airway smooth muscle cells (ASMC) isolated from the airways of murine and human lungs. Importantly, the loss of IL-31RA attenuated AHR but had no effect on inflammation and goblet cell hyperplasia in mice challenged with allergens or treated with IL-13 or IFNγ. We show that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression, augmenting calcium levels and myosin light chain phosphorylation in human and murine ASMC. These findings identify a role for IL-31RA in AHR that is distinct from airway inflammation and goblet cell hyperplasia in asthma.

Expression, purification, and biological characterization of recombinant human interleukin-31 protein

Interleukin-31 (IL-31), belonging to the IL-6 cytokine family, is involved in skin inflammation and pruritus, as well as some tumors' progression. Here, we reported the expression and purification of recombinant human IL-31 (rhIL-31) using a prokaryotic system. This recombinant protein was expressed in the form of inclusion bodies, refolded and purified by size-exclusion chromatography. Circular dichroism analysis revealed that the secondary structure of rhIL-31 was mainly composed of alpha-helix, which is in consistence with the 3D model structure built by AlphaFold server. In vitro studies showed that rhIL-31 exhibited a good binding ability to the recombinant hIL-31 receptor alpha fused with human Fc fragment (rhIL-31RA-hFc) with EC50 value of 16.36 µg/mL in ELISA assay. Meanwhile, flow cytometry demonstrated that rhIL-31 was able to bind to hIL-31RA or hOSMRβ expressed on the cell surface, independently. Furthermore, rhIL-31 could induce the phosphorylation of STAT3 in A549 cells. In conclusion, the prepared rhIL-31 in this study possesses the binding ability to its receptors, and can activate the signal pathway of JAK/STAT. Thus, it can be applied in further studies, including investigation of hIL-31-related diseases, structural analysis, and development of therapeutic drugs, and monoclonal antibodies targeting hIL-31.

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.

Interleukin 31 receptor alpha augments muscarinic acetylcholine receptor 3-driven calcium signaling and airway hyperresponsiveness in asthma

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and goblet cell hyperplasia. Both Th1 and Th2 cytokines, including IFN-γ, IL-4, and IL-13 have been shown to induce asthma; however, the underlying mechanisms remain unclear. We observed a significant increase in the expression of IL-31RA, but not its cognate ligand IL-31 during allergic asthma. In support of this, IFN-γ and Th2 cytokines, IL-4 and IL-13, upregulated IL-31RA but not IL-31 in airway smooth muscle cells (ASMC). Importantly, the loss of IL-31RA attenuated AHR but had no effects on inflammation and goblet cell hyperplasia in allergic asthma or mice treated with IL-13 or IFN-γ. Mechanistically, we demonstrate that IL-31RA functions as a positive regulator of muscarinic acetylcholine receptor 3 expression and calcium signaling in ASMC. Together, these results identified a novel role for IL-31RA in AHR distinct from airway inflammation and goblet cell hyperplasia in asthma.

Interleukin-31 promotes fibrosis and T helper 2 polarization in systemic sclerosis

Systemic sclerosis (SSc) is a chronic multisystem disorder characterized by fibrosis and autoimmunity. Interleukin (IL)-31 has been implicated in fibrosis and T helper (Th) 2 immune responses, both of which are characteristics of SSc. The exact role of IL-31 in SSc pathogenesis is unclear. Here we show the overexpression of IL-31 and IL-31 receptor A (IL-31RA) in dermal fibroblasts (DFs) from SSc patients. We elucidate the dual role of IL-31 in SSc, where IL-31 directly promotes collagen production in DFs and indirectly enhances Th2 immune responses by increasing pro-Th2 cytokine expression in DFs. Furthermore, blockade of IL-31 with anti-IL-31RA antibody significantly ameliorates fibrosis and Th2 polarization in a mouse model of SSc. Therefore, in addition to defining IL-31 as a mediator of fibrosis and Th2 immune responses in SSc, our study provides a rationale for targeting the IL-31/IL-31RA axis in the treatment of SSc.

Systemic sclerosis (SSc) disease involves multisystem fibrosis and autoimmunity with limited treatment options. Here the authors demonstrate that IL-31 and IL-31RA are overexpressed in dermal fibroblasts from SSc patients and show that fibrosis and cytokine release can be reduced upon blocking of IL-31/IL-31RA.

Interleukin-31: The "itchy" cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main "drivers" of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H 2 cells play a central role in AD and release high levels of T_H 2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.

IL-31 Inhibition as a Therapeutic Approach for the Management of Chronic Pruritic Dermatoses

Chronic pruritus is a debilitating symptom with limited treatment options. Identifying molecular targets underlying chronic pruritic dermatoses is essential for the development of novel, targeted therapies. IL-31 is an important mediator of itch by integrating dermatologic, neural, and immune systems. IL-31 helps induce and maintain chronic pruritus via both indirect stimulation of inflammatory cells and through direct neural sensitization. IL-31 is overexpressed in various chronic pruritic skin conditions, and exogenous IL-31 induces itch and scratching behavior. Studies have demonstrated that IL-31R and IL-31 antagonism significantly reduces itch in patients with atopic dermatitis and prurigo nodularis, two extremely pruritic skin conditions. Emerging evidence, including recent phase II clinical trials of IL-31R antagonists, demonstrates that IL-31 plays an important role in itch signaling. Additional studies are ongoing to evaluate IL-31R and IL-31 antagonism as treatments of chronic pruritus.

Neutrophil-Derived Oncostatin M Triggers Diverse Signaling Pathways during Pneumonia

Pneumonia is a major public health concern, causing significant morbidity and mortality annually despite the broad use of antimicrobial agents. Underlying many of the severe sequelae of acute lung infections is dysfunction of the immune response, which remains incompletely understood yet is an attractive target of adjunct therapy in pneumonia. Here, we investigate the role of oncostatin M (OSM), a pleiotropic cytokine of the interleukin-6 (IL-6) family, and how its signaling modulates multiple innate immune pathways during pneumonia. Previously, we showed that OSM is necessary for neutrophil recruitment to the lungs during pneumonia by stimulating STAT3-driven CXCL5 expression. In this study, transcriptional profiling of whole-lung pneumonia with OSM neutralization revealed 241 differentially expressed genes following only 6 h of infection. Many downregulated genes are associated with STAT1, STAT3, and interferon signaling, suggesting these pathways are induced by OSM early in pneumonia. Interestingly, STAT1 and STAT3 activation was subsequently upregulated with OSM neutralization by 24 h, suggesting that OSM interruption dysregulates these central signaling pathways. When we investigated the source of OSM in pneumonia, neutrophils and, to a lesser extent, macrophages appear to be primary sources, suggesting a positive feedback loop of OSM production by neutrophils. From these studies, we conclude that OSM produced by recruited neutrophils tunes early innate immune signaling pathways, improving pneumonia outcomes.

Interleukin-31 Signaling Bridges the Gap Between Immune Cells, the Nervous System and Epithelial Tissues

Pruritus represents one of the most common symptoms in dermatology and general medicine. Chronic pruritus severely impairs the quality of life of affected patients. During the last two decades a number of modulators and mediator of pruritus have been identified. Recently, Interleukin (IL)-31 and its receptor complex attracted significant interest, as clinical phase two studies demonstrated therapeutic efficacy of the neutralizing IL-31 receptor A (IL-31RA) antibody nemolizumab in patients suffering from atopic dermatitis or prurigo nodularis. IL-31 has also been shown to play relevant roles in allergic contact dermatitis, urticaria, mastocytosis, allergic rhinitis and asthma. Here, we summarize the current knowledge of the novel cytokine IL-31 and its receptor regarding cellular origin, regulation, signaling pathways and their involvement in biological processes such as pruritus, neuronal growth, inflammation, barrier dysfunction and tissue remodeling.

IL-31 transgenic mice show reduced allergen-induced lung inflammation

Interleukin-31 (IL-31) is a Th2 cell-derived cytokine that has been closely linked to pruritic skin inflammation. More recently, enhanced IL-31 serum levels have also been observed in patients with allergic rhinitis and allergic asthma. Therefore, the main aim of this study was to unravel the contribution of IL-31 to allergen-induced lung inflammation. We analyzed lung inflammation in response to the timothy grass (Phleum pratense) pollen allergen Phl p 5 in C57BL/6 wild-type (wt) mice, IL-31 transgenic (IL-31tg) mice, and IL-31 receptor alpha-deficient animals (IL-31RA-/- ). IL-31 and IL-31RA levels were monitored by qRT-PCR. Cellular infiltrate in bronchoalveolar lavage fluid (BALF) and lung tissue inflammation, mucus production as well as epithelial thickness were measured by flow cytometry and histomorphology. While allergen challenge induced IL-31RA expression in lung tissue of wt and IL-31tg mice, high IL-31 expression was exclusively observed in lung tissue of IL-31tg mice. Upon Phl p 5 challenge, IL-31tg mice showed reduced numbers of leukocytes and eosinophils in BALF and lung tissue as well as diminished mucin expression and less pronounced epithelial thickening compared to IL-31RA-/- or wt animals. These findings suggest that the IL-31/IL-31RA axis may regulate local, allergen-induced inflammation in the lungs.

Serum concentrations of IL-31 in dogs with nonpruritic mast cell tumours or lymphoma

BACKGROUND

The aim of this study was to compare serum interleukin (IL)-31 concentrations in dogs with lymphoma and mast cell tumours (MCT) without pruritus to those of healthy dogs.

HYPOTHESIS/OBJECTIVES

To determine if IL-31 plays a role in tumour pathogenesis and if IL-31 could be a biological marker for disease progression.

ANIMALS

Forty-eight healthy dogs and 36 dogs with neoplasia [multicentric lymphoma (14), MCT (15) and cutaneous lymphoma (7)] were included in the study.

METHODS AND MATERIALS

Dogs with neoplasia were assigned to three different groups. Group 1 consisted of patients with multicentric lymphoma, which were diagnosed by cytological, histopathological and clonality investigations. Thoracic radiographs, ultrasound examination of the abdominal cavity, and fine-needle aspirates from liver and spleen were used to determine the lymphoma stage Patients with cutaneous lymphoma, diagnosed by cytological and histopathological findings, were included in Group 2. Patients with MCT, diagnosed by cytological and histopathological findings, were included in Group 3. Serum was frozen at -80ºC before measuring the concentration of IL-31 via a Simoa ultra-sensitive, fully automated two-step immunoassay.

RESULTS

Serum concentrations of IL-31, regardless of the disease and its staging, were within the normal range in all patients; there was no difference between any of the different tumour groups and healthy dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

IL-31 is not likely to be involved in the pathogenesis of canine MCT or lymphoma without pruritus.

IL-31 induces antitumor immunity in breast carcinoma

Background

Immunomodulatory agents that induce antitumor immunity have great potential for treatment of cancer. We have previously shown that interleukin (IL)-31, a proinflammatory cytokine from the IL-6 family, acts as an antiangiogenic agent. Here, we characterize the immunomodulatory effect of IL-31 in breast cancer.

Methods

In vivo breast carcinoma models including EMT6 and PyMT cell lines were used to analyze the effect of IL-31 on the composition of various immune cells in the tumor microenvironment using high-throughput flow cytometry. In vitro studies using isolated cytotoxic T cells, CD4⁺ T cells, myeloid-derived suppressor cells (MDSCs) and macrophages were carried out to study IL-31 immunological activity. The generation of recombinant IL-31 bound to IgG backbone was used to test IL-31 therapeutic activity.

Results

The growth rate of IL-31-expressing breast carcinomas is decreased in comparison with control tumors due, in part, to antitumor immunomodulation. Specifically, cytotoxic T cell activity is increased, whereas the levels of CD4⁺ T cells, MDSCs, and tumor-associated macrophages are decreased in IL-31-expressing tumors. These cellular changes are accompanied by a cytokine profile associated with antitumor immunity. In vitro, IL-31 directly inhibits CD4⁺ Th0 cell proliferation, and the expression of Th2 canonical factors GATA3 and IL-4. It also promotes CD8⁺ T cell activation through inhibition of MDSC activity and motility. Clinically, in agreement with the mouse data, alterations in immune cell composition in human breast cancer biopsies were found to correlate with high expression of IL-31 receptor A (IL-31Ra). Furthermore, high coexpression of IL-31Ra, IL-2 and IL-4 in tumors correlates with increased survival. Lastly, to study the therapeutic potential of IL-31, a recombinant murine IL-31 molecule was fused to IgG via a linker region (IL-31-L-IgG). This IL-31-L-IgG therapy demonstrates antitumor therapeutic activity in a murine breast carcinoma model.

Conclusions

Our findings demonstrate that IL-31 induces antitumor immunity, highlighting its potential utility as a therapeutic immunomodulatory agent.

IL-24: A new player in the pathogenesis of pro-inflammatory and allergic skin diseases

Interleukin (IL)-24 is a member of the IL-20 family of cytokines and is produced by various types of cells, such as CD4⁺ T cells, NK cells, mast cells, keratinocytes, bronchial epithelial cells, and myofibroblasts. Previous studies suggest that IL-24 plays an essential role in the pathogenesis of pro-inflammatory autoimmune disorders such as psoriasis, arthritis, and inflammatory bowel diseases. However, the role of IL-24 in the pathogenesis of allergic diseases has been elusive. It has already been reported that IL-24 is involved in the pathogenesis of allergic lung and skin diseases. Moreover, we have recently revealed for the first time the pivotal functions of IL-24 in IL-13-mediated skin barrier dysfunction in atopic dermatitis (AD), which is known to be a characteristic of AD caused by Th2 cytokines such as IL-4 or IL-13. In this review, we show recent advances in the basic characteristics of IL-24 and its novel functions in the pathogenesis of allergic skin inflammation, focusing on AD. A better understanding of the role of IL-24 in allergic diseases can lead to the development of new therapeutic options.

Role of the Pruritic Cytokine IL-31 in Autoimmune Skin Diseases

Many autoimmune skin diseases, such as bullous pemphigoid (BP), psoriasis and certain types of chronic urticaria, are associated with intensive pruritus. While histamine and neuropeptides have previously been ascribed to play a role in itch that accompanies these diseases, recent evidence suggests that the pruritogenic cytokine interleukin (IL)-31 is a major driver of pruritic responses. IL-31 was originally shown to be produced by activated helper T cells, particularly Th2 cells, mast cells, macrophages and dendritic cells. However, more recent evidence demonstrated that eosinophils are a major source of this cytokine too, particularly in bullous pemphigoid. Basophils have also been shown to express the cytokine which, through autocrine action, strongly supports the production of other Th2-type cytokines from these cells. These investigations suggest that the dynamic recruitment of eosinophils and basophils in some autoimmune skin diseases could play an important role in the severity of IL-31-mediated itch. Furthermore, these studies suggest that IL-31, in addition to its pruritic actions, also has potential immunomodulatory roles in terms of supporting Th2-type immunity, which often underpins IgE-associated autoimmune diseases (such as bullous pemphigoid and urticaria) as well as allergies. While the role of IL-31 in psoriasis remains to be clarified, current evidence shows that this cytokine plays a major role in BP, chronic spontaneous urticaria and dermatomyositis. This suggests potential use of IL-31 receptor-blocking therapeutic approaches (e.g., Nemolizumab) for the treatment of IL-31-associated disorders.

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.

IL-31 plays dual roles in lung inflammation in an OVA-induced murine asthma model

Interleukin 31 (IL-31) is a four-helix cytokine made predominantly by Th2 CD4⁺ T cells. It was initially identified as being associated with the promotion of atopic dermatitis, where increased levels of IL-31 levels have been found and IL-31 induced the expression of proinflammatory cytokines and chemokines in a human bronchial epithelial cell line. However, subsequent study has shown that IL-31RA knockout mice developed exacerbated type 2 inflammation in the lung following infection with Schistosoma mansoni eggs. In this study, we investigated the dynamic expression of IL-31 and IL-31RA during eight consecutive ovalbumin (OVA) challenges and measured the chemokines from lung alveolar epithelial cells induced by IL-31. In addition, we examined the effect deletion of IL-31RA has on lung inflammation and the differentiation of CD4⁺ T cells. Our results demonstrate that the expression of IL-31 and IL-31RA was elevated after each weekly OVA challenge, although slightly less of both observed after the first week of OVA challenge. IL-31 also promoted the expression of inflammatory chemokines CCL5, CCL6, CCL11, CCL16, CCL22, CCL28, CX3CL1, CXCL3, CXCL14 and CXCL16 in alveolar epithelial cells. Migration of macrophages and T cells was enhanced by culture supernatants of IL-31-stimulated alveolar epithelial cells. Lastly, and in contrast to the IL-31 results, mice deficient in IL-31RA developed exacerbated lung inflammation, increased IL-4-positive cell infiltrates and elevated Th2 cytokine responses in draining lymph nodes. The proliferation of IL-31RA^-/- CD4⁺ T cells was enhanced in vitro after anti-CD3/anti-CD28 antibody stimulation. These data indicate that IL-31/IL-31RA may play dual roles, first as an early inflammatory mediator promoting the secretion of chemokines to recruit inflammatory cells, and subsequently as a late inflammatory suppressor, limiting Th2 cytokine responses in allergic asthma.

The IL-13/periostin/IL-24 pathway causes epidermal barrier dysfunction in allergic skin inflammation

BACKGROUND

Barrier dysfunction is an important feature of atopic dermatitis (AD) in which IL-4 and IL-13, signature type 2 cytokines, are involved. Periostin, a matricellular protein induced by IL-4 or IL-13, plays a crucial role in the onset of allergic skin inflammation, including barrier dysfunction. However, it remains elusive how periostin causes barrier dysfunction downstream of the IL-13 signal.

METHODS

We systematically identified periostin-dependent expression profile using DNA microarrays. We then investigated whether IL-24 downregulates filaggrin expression downstream of the IL-13 signals and whether IL-13-induced IL-24 expression and IL-24-induced downregulation of filaggrin expression are dependent on the JAK/STAT pathway. To build on the significance of in vitro findings, we investigated expression of IL-24 and activation of STAT3 in mite-treated mice and in AD patients.

RESULTS

We identified IL-24 as an IL-13-induced molecule in a periostin-dependent manner. Keratinocytes are the main IL-24-producing tissue-resident cells stimulated by IL-13 in a periostin-dependent manner via STAT6. IL-24 significantly downregulated filaggrin expression via STAT3, contributing to barrier dysfunction downstream of the IL-13/periostin pathway. Wild-type mite-treated mice showed significantly enhanced expression of IL-24 and activation of STAT3 in the epidermis, which disappeared in both STAT6-deficient and periostin-deficient mice, suggesting that these events are downstream of both STAT6 and periostin. Moreover, IL-24 expression was enhanced in the epidermis of skin tissues taken from AD patients.

CONCLUSIONS

The IL-13/periostin pathway induces IL-24 production in keratinocytes, playing an important role in barrier dysfunction in AD.

IL-33/IL-31 Axis: A Potential Inflammatory Pathway

Cytokines play an important role in the regulation of the immune system (adaptive and innate). Given their importance in proinflammatory processes, cytokines have been used for understanding the pathogenesis and as biomarkers in many diseases. IL-31 and IL-33 are still considered novel cytokines. IL-31 controls signalling and regulates a huge amount of biological functions: it induces proinflammatory cytokines, regulates cell proliferation, and is involved also in tissue remodelling. On the other hand, IL-33 has been identified as an “alarmin” released from the epithelial cells and from different human tissues and organs after a damage following, that is, an inflammatory process. The aim of this literature review is to strengthen the hypothesis about an IL-31/IL-33 axis by evaluating the most recent studies linking these two cytokines. Literature data showed that, in many cases, IL-31 and IL-33 are linked to each other and that their expression is correlated with disease severity. The presence of one interleukin might stimulate the induction of the other, amplifying inflammation and the consequent detrimental processes. In a near future, influencing their balance could be helpful in modulating the first responses of the immune system in order to prevent the development of many inflammation-related diseases.

Genetic Association of Interleukin-31 Gene Polymorphisms with Epithelial Ovarian Cancer in Chinese Population

Roles of interleukin-31 (IL-31) in the development and progression of human epithelial ovarian cancer are largely unknown. Studies report that the polymorphisms, rs7977932 C>G and rs4758680 C>A in IL-31, affect the expression level of IL-31. In the present study, we examined 412 patients with epithelial ovarian cancer and 428 healthy individuals to explore whether these polymorphisms are associated with the epithelial ovarian cancer in Chinese women. The genotype of the polymorphisms in each individual was identified. The associations of the polymorphisms with patients' clinical characteristics and outcomes were evaluated. For rs7977932, the frequency of the CG/GG was significantly decreased in patients with epithelial ovarian cancer. However, the frequency of the rs4758680 CA/AA was significantly increased in those patients. Moreover, the frequency of rs7977932 CG/GG genotype was significantly higher in patients with less advanced FIGO stages. Kaplan-Meier curve showed that patients with CG/GG genotypes of rs7977932 had a decreased risk for recurrence compared to those with CC genotype. Our findings suggested that rs7977932 and rs4758680 of IL-31 may be associated with the development and progression of the epithelial ovarian cancer in the Chinese population. IL-31, therefore, may be a potential therapeutic target for the development of drugs to treat the disease.

IL-31: A new key player in dermatology and beyond

IL-31 is a novel cytokine expressed in many human tissues and involved mainly in T_H2-weighted inflammation. IL-31 signals through a receptor complex consisting of IL-31 receptor α and oncostatin M receptor β. The available data show that IL-31 is strongly linked with chronic pruritic skin disorders, such as atopic eczema, and represents a novel target for directed drug therapy. Regulation of immune responses and cellular differentiation and proliferation are recently elucidated effects of IL-31, suggesting a more complex and diverse area of effect for this novel cytokine. This review summarizes the current knowledge on IL-31 and its receptors and the involvement of IL-31 in diseases both in human subjects and mouse models.

Monoclonal antibodies against interleukin 13 and interleukin 31RA in development for atopic dermatitis

The interleukin 13 (IL-13) and IL-31 cytokines and inflammatory pathways have been identified as important for the pathophysiology of atopic dermatitis (AD). Monoclonal antibodies against IL-13 have been studied for the treatment of asthma since 2011. More recently, 2 phase 2 trials have been completed with these antibodies in AD treatment. In both trials, significant reductions of Eczema Area and Severity Index scores were seen. IL-31 is thought to play a role transmitting itch sensation to the central nervous system, and blocking IL-31 activity reduces itch in patients with AD. One phase 2 trial has been completed for a humanized antibody against IL-31 receptor alpha, which is 1 subunit of the IL-31 receptor complex. This study showed significant dose-dependent reductions in pruritus, Eczema Area and Severity Index scores, and markers of sleep quality. Initial clinical trials for monoclonal antibodies against IL-13 and IL-31 receptor A all show promise, although long-term safety and efficacy data are lacking. Nevertheless, these medications will likely play a role in the treatment of moderate-to-severe AD.

Potential Involvement of the Epidermal Growth Factor Receptor Ligand Epiregulin and Matrix Metalloproteinase-1 in Pathogenesis of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease of the nose and paranasal sinuses that presents without or with nasal polyps (CRSwNP). Notable features of CRSwNP are the frequent presence of type 2 allergic inflammation and high prevalence of Staphylococcus aureus (SA) colonization. As inflammation persists, sinus tissue undergoes epithelial damage and repair along with polyp growth, despite active medical management. Because one feature of damaged tissue is enhancement of growth factor signaling, we evaluated the presence of epidermal growth factor receptor (EGFR) ligands and matrix metalloproteinases (MMPs) in CRS. The objectives of this study were to analyze the expression of EGFR ligands and MMPs in patients with CRS and to investigate the possible role of SA on epithelial activation. Sinonasal tissues were collected during surgery from control subjects and patients with CRS. Tissues were processed as described previously for analysis of mRNA (RT-PCR) and proteins (ELISA) for the majority of EGFR ligands within the tissue extracts. CRS tissue was used for evaluation of the distribution of epiregulin (EREG), an EGFR ligand, and MMP-1 by immunohistochemistry. In parallel studies, expression of these genes and proteins was analyzed in cultured primary airway epithelial cells. Elevated expression of EREG and MMP-1 mRNA and protein was observed in uncinate and polyp tissue from patients with CRSwNP. Immunohistochemistry study of clinical samples revealed that airway epithelial cells expressed both of these proteins. Cultured primary human airway epithelial cells expressed MMP-1, and MMP-1 was further induced by stimulation with EREG or heat-killed SA (HKSA). The induction of MMP-1 by HKSA was blocked by an antibody against EREG, suggesting that endogenous EREG induces MMP-1 after stimulation with HKSA. EREG and MMP-1 were found to be elevated in nasal polyp and uncinate tissues in patients with CRSwNP. Elevated expression of EREG and MMP-1 may be related to polyp formation in CRS, and colonization of SA might further enhance this process.

The antiangiogenic role of the pro-inflammatory cytokine interleukin-31

Pro-inflammatory cytokines in the tumor microenvironment are known for their ability to either inhibit or promote cancer progression. Here we evaluated the role of Interleukin-31 (IL31), a protein belonging to the pro-inflammatory IL-6 cytokine family which has been characterized in autoimmune disease, in tumorigenesis. We show that IL31 and its receptor, IL31RA, are highly expressed in various human and mouse cancer cell lines, as well as in tumor specimens from cancer patients. MC38 murine colon carcinoma cells depleted of IL31 exhibit an increase in invasive and migratory properties in vitro, effects that are reversed by supplementing the cells with exogenous IL31. In vivo, IL31-depleted MC38 tumor cells implanted to mice grow faster than control tumors. In contrast, MC38 tumor-bearing mice infused with recombinant IL31, exhibit a significant reduction in tumor growth than control mice. Furthermore, IL31 infusion reduces the number of metastatic lesions in the lungs of mice bearing 4T1 murine metastatic breast carcinoma. Lastly, injecting tumor-bearing, chemotherapy-treated mice with a long-lived IL31-IgG fusion protein reduces tumor growth, angiogenesis and pulmonary metastasis to a greater extent than when chemotherapy is used alone. The IL31 anti-tumor activity is explained, in part, by the anti-angiogenic effects demonstrated both in vitro and in vivo highlighting the potential use of IL31 as an anti-cancer drug.

Non-cell-autonomous activation of IL-6/STAT3 signaling mediates FGF19-driven hepatocarcinogenesis

Hepatocellular carcinoma (HCC), a primary malignancy of the liver, is the second leading cause of cancer mortality worldwide. Fibroblast Growth Factor 19 (FGF19) is one of the most frequently amplified genes in HCC patients. Moreover, mice expressing an FGF19 transgene have been shown to develop HCC. However, the downstream signalling pathways that mediate FGF19-dependent tumorigenesis remain to be deciphered. Here we show that FGF19 triggers a previously unsuspected, non-cell-autonomous program to activate STAT3 signalling in hepatocytes through IL-6 produced in the liver microenvironment. We show that the hepatocyte-specific deletion of Stat3, genetic ablation of Il6, treatment with a neutralizing anti-IL-6 antibody or administration of a small-molecule JAK inhibitor, abolishes FGF19-induced tumorigenesis, while the regulatory functions of FGF19 in bile acid, glucose and energy metabolism remain intact. Collectively, these data reveal a key role for the IL-6/STAT3 axis in potentiating FGF19-driven HCC in mice, a finding which may have translational relevance in HCC pathogenesis.

Fibroblast Growth Factor 19 (FGF19) neutralizing antibodies inhibit hepatocellular carcinoma (HCC) growth but have safety issues. Here, the authors show that FGF19 promotes HCC by activating STAT3 signalling via IL-6 production and that targeting IL-6 pathway abolishes FGF19-induced HCC without side effects.

Oncostatin M overexpression induces skin inflammation but is not required in the mouse model of imiquimod-induced psoriasis-like inflammation

Oncostatin M (OSM) has been reported to be overexpressed in psoriasis skin lesions and to exert proinflammatory effects in vitro on human keratinocytes. Here, we report the proinflammatory role of OSM in vivo in a mouse model of skin inflammation induced by intradermal injection of murine OSM-encoding adenovirus (AdOSM) and compare with that induced by IL-6 injection. Here, we show that OSM potently regulates the expression of genes involved in skin inflammation and epidermal differentiation in murine primary keratinocytes. In vivo, intradermal injection of AdOSM in mouse ears provoked robust skin inflammation with epidermal thickening and keratinocyte proliferation, while minimal effect was observed after AdIL-6 injection. OSM overexpression in the skin increased the expression of the S100A8/9 antimicrobial peptides, CXCL3, CCL2, CCL5, CCL20, and Th1/Th2 cytokines, in correlation with neutrophil and macrophage infiltration. In contrast, OSM downregulated the expression of epidermal differentiation genes, such as cytokeratin-10 or filaggrin. Collectively, these results support the proinflammatory role of OSM when it is overexpressed in the skin. However, OSM expression was not required in the murine model of psoriasis induced by topical application of imiquimod, as demonstrated by the inflammatory phenotype of OSM-deficient mice or wild-type mice treated with anti-OSM antibodies.

Interleukin-31 expression and relation to disease severity in human asthma

Interleukin 31 (IL-31) is a novel T helper type 2 effector cytokine that plays an important role in the pathogenesis of allergic diseases. However, its role in human asthma remains unclear. The aim of this study was to measure IL-31 levels in the serum, bronchoalveolar lavage fluid (BALF) and bronchial tissue of asthmatics and healthy subjects, and identify its possible correlation to disease severity. We quantified IL-31 levels in the serum of patients with asthma (n = 44), as well as in controls (n = 22). Of these subjects, 9 asthmatics and five controls underwent bronchoscopy with endobronchial biopsy and BALF collection. Our data showed that serum and BALF IL-31 levels were significantly elevated in patients with asthma compared with controls. Expressions of IL-31 and IL-31 receptor (IL-31RA and OSMR) were more prominent in the bronchial tissue in severe compared to mild asthma and controls. Serum IL-31 levels correlated positively with Th2 related cytokines (IL-5, IL-13, and TSLP), asthma severity or total serum immunoglobulin E (IgE), and inversely with asthma control and the forced expiratory volume in 1 second (FEV₁). The current data may provide insight into the underlying pathogenesis of asthma, in which IL-31 has an important pathogenic role.

Methylation and microRNA-mediated epigenetic regulation of SOCS3

Epigenetic gene silencing of several genes causes different pathological conditions in humans, and DNA methylation has been identified as one of the key mechanisms that underlie this evolutionarily conserved phenomenon associated with developmental and pathological gene regulation. Recent advances in the miRNA technology with high throughput analysis of gene regulation further increased our understanding on the role of miRNAs regulating multiple gene expression. There is increasing evidence supporting that the miRNAs not only regulate gene expression but they also are involved in the hypermethylation of promoter sequences, which cumulatively contributes to the epigenetic gene silencing. Here, we critically evaluated the recent progress on the transcriptional regulation of an important suppressor protein that inhibits cytokine-mediated signaling, SOCS3, whose expression is directly regulated both by promoter methylation and also by microRNAs, affecting its vital cell regulating functions. SOCS3 was identified as a potent inhibitor of Jak/Stat signaling pathway which is frequently upregulated in several pathologies, including cardiovascular disease, cancer, diabetes, viral infections, and the expression of SOCS3 was inhibited or greatly reduced due to hypermethylation of the CpG islands in its promoter region or suppression of its expression by different microRNAs. Additionally, we discuss key intracellular signaling pathways regulated by SOCS3 involving cellular events, including cell proliferation, cell growth, cell migration and apoptosis. Identification of the pathway intermediates as specific targets would not only aid in the development of novel therapeutic drugs, but, would also assist in developing new treatment strategies that could successfully be employed in combination therapy to target multiple signaling pathways.

Increased levels of interleukin 31 (IL-31) in osteoporosis

Background

Several inflammatory cytokines play a key part in the induction of osteoporosis. Until now, involvement of the Th2 cytokine interleukin-31 (IL-31) in osteoporosis hadn’t yet been studied. IL-31 is a proinflammatory cytokine mediating multiple immune functions, whose involvement in a wide range of diseases, such as atopic dermatitis, inflammatory bowel diseases and cutaneous lymphomas, is now emerging. Given the important role of IL-31 in inflammation, we measured its serum levels in postmenopausal osteoporotic patients.

Methods and results

In fifty-six postmenopausal females with osteoporosis and 26 healthy controls, bone mineral density (BMD) measurements were performed by using calcaneal quantitative ultrasound (QUS) technique, confirmed at the lumbar spine and hip by dual energy X-ray absorptiometry (DXA). Both patients and controls were divided according to age (less or more than 65 years) and disease severity (T-score levels and presence of fractures). Serum IL-31 levels were measured by ELISA technique. Osteoporotic patients exhibited elevated levels of serum IL-31 compared with healthy controls (43.12 ± 6.97 vs 29.58 ± 6.09 pg/ml; p < 0.049). IL-31 expression was higher in over 65 years old patients compared to age-matched controls (45 ± 11.05 vs. 17.92 ± 5.92; p < 0.01), whereas in younger subjects no statistically significant differences were detected between patients and controls (37.91 ± 6.9 vs 32.08 ± 8.2). No statistically significant differences were found between IL-31 levels in patients affected by mild (T-score > -3) compared to severe (T-score < -3) osteoporosis (59.17 ± 9.22 vs 37.91 ± 10.52), neither between fractured and unfractured osteoporotic women (33.75 ± 9.16 vs 51.25 ± 8.9).

Conclusions

We showed for the first time an increase of IL-31 serum levels in postmenopausal women with decreased BMD. Although they did not reflect the severity of osteoporosis and/or the presence of fractures, they clearly correlated with age, as reflected by the higher levels of this cytokine in aged patients.

Prerequisites for Functional Interleukin 31 Signaling and Its Feedback Regulation by Suppressor of Cytokine Signaling 3 (SOCS3)

Interleukin-31 (IL-31) is a T helper type 2 cell-derived cytokine tightly associated with inflammatory skin disorders. IL-31-induced signaling is mediated by a receptor complex composed of oncostatin M receptor β and the cytokine-specific receptor subunit IL-31Rα, of which there are several isoforms. The latter can be classified as long or short isoforms with respect to their intracellular domain. At present, the signaling capabilities of the different isoforms remain inchoately understood, and potential mechanisms involved in negative regulation of IL-31Rα signaling have so far not been studied in detail. Here, we show that both the long and short isoforms of IL-31Rα are capable of inducing STAT signaling. However, the presence of a functional JAK-binding box within IL-31Rα is an essential prerequisite for functional IL-31-mediated STAT3 signaling. Moreover, both the long and short isoforms require oncostatin M receptor β for their activity. We also show that IL-31 induces expression of four suppressor of cytokine signaling family members and provide evidence that SOCS3 acts as a potent feedback inhibitor of IL-31-induced signaling. Taken together, this study identifies crucial requirements for IL-31 signaling and shows its counter-regulation by SOCS3.

Th2 Cytokines Augment IL-31/IL-31RA Interactions via STAT6-dependent IL-31RA Expression

Interleukin 31 receptor α (IL-31RA) is a novel Type I cytokine receptor that pairs with oncostatin M receptor to mediate IL-31 signaling. Binding of IL-31 to its receptor results in the phosphorylation and activation of STATs, MAPK, and JNK signaling pathways. IL-31 plays a pathogenic role in tissue inflammation, particularly in allergic diseases. Recent studies demonstrate IL-31RA expression and signaling in non-hematopoietic cells, but this receptor is poorly studied in immune cells. Macrophages are key immune-effector cells that play a critical role in Th2-cytokine-mediated allergic diseases. Here, we demonstrate that Th2 cytokines IL-4 and IL-13 are capable of up-regulating IL-31RA expression on both peritoneal and bone marrow-derived macrophages from mice. Our data also demonstrate that IL-4Rα-driven IL-31RA expression is STAT6 dependent in macrophages. Notably, the inflammation-associated genes Fizz1 and serum amyloid A (SAA) are significantly up-regulated in M2 macrophages stimulated with IL-31, but not in IL-4 receptor-deficient macrophages. Furthermore, the absence of Type II IL-4 receptor signaling is sufficient to attenuate the expression of IL-31RA in vivo during allergic asthma induced by soluble egg antigen, which may suggest a role for IL-31 signaling in Th2 cytokine-driven inflammation and allergic responses. Our study reveals an important counter-regulatory role between Th2 cytokine and IL-31 signaling involved in allergic diseases.

Myocardial healing requires Reg3β-dependent accumulation of macrophages in the ischemic heart

Cardiac healing after myocardial ischemia depends on the recruitment and local expansion of myeloid cells, particularly macrophages. Here we identify Reg3β as an essential regulator of macrophage trafficking to the damaged heart. Using mass spectrometry-based secretome analysis, we found that dedifferentiating cardiomyocytes release Reg3β in response to the cytokine OSM, which signals through Jak1 and Stat3. Loss of Reg3β led to a large decrease in the number of macrophages in the ischemic heart, accompanied by increased ventricular dilatation and insufficient removal of neutrophils. This defect in neutrophil removal in turn caused enhanced matrix degradation, delayed collagen deposition and increased susceptibility to cardiac rupture. Our data indicate that OSM, acting through distinct intracellular pathways, regulates both cardiomyocyte dedifferentiation and cardiomyocyte-dependent regulation of macrophage trafficking. Release of OSM from infiltrating neutrophils and macrophages initiates a positive feedback loop in which OSM-induced production of Reg3β in cardiomyocytes attracts additional OSM-secreting macrophages. The activity of the feedback loop controls the degree of macrophage accumulation in the heart, which is instrumental in myocardial healing.

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.

The interleukin (IL)-31/IL-31R axis contributes to tumor growth in human follicular lymphoma

Interleukin (IL)-31A binds to an heterodimer composed of IL-31 receptor A (IL-31RA) and Oncostatin M Receptor (OSMR). The IL-31/IL-31R complex is involved in the pathogenesis of various skin diseases, including cutaneous T-cell lymphoma. No information is available on the relations between the IL-31/IL-31R complex and B-cell lymphoma. Here we have addressed this issue in follicular lymphoma (FL), a prototypic germinal center(GC)-derived B-cell malignancy. IL-31 enhanced primary FL cell proliferation through IL-31R-driven signal transducer and activator of transcription factor 1/3 (STAT1/3), extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt phosphorylation. In contrast, GC B cells did not signal to IL-31 in spite of IL-31R expression. GC B cells expressed predominantly the inhibitory short IL-31RA isoform, whereas FL cells expressed predominantly the long signaling isoform. Moreover, GC B cells lacked expression of other IL-31RA isoforms potentially involved in the signaling pathway. IL-31 protein expression was significantly higher in surface membrane than in cytosol of both FL and GC B cells. IL-31 was detected in plasma membrane microvesicles from both cell types but not released in soluble form in culture supernatants. IL-31 and IL-31RA expression was higher in lymph nodes from FL patients with grade IIIa compared with grade I/II, suggesting a paracrine and/or autocrine role of IL-31/IL-31RA complex in tumor progression through microvesicle shedding.

A novel approach to the discovery of survival biomarkers in glioblastoma using a joint analysis of DNA methylation and gene expression

Glioblastoma multiforme (GBM) is the most aggressive of all brain tumors, with a median survival of less than 1.5 years. Recently, epigenetic alterations were found to play key roles in both glioma genesis and clinical outcome, demonstrating the need to integrate genetic and epigenetic data in predictive models. To enhance current models through discovery of novel predictive biomarkers, we employed a genome-wide, agnostic strategy to specifically capture both methylation-directed changes in gene expression and alternative associations of DNA methylation with disease survival in glioma. Human GBM-associated DNA methylation, gene expression, IDH1 mutation status, and survival data were obtained from The Cancer Genome Atlas. DNA methylation loci and expression probes were paired by gene, and their subsequent association with survival was determined by applying an accelerated failure time model to previously published alternative and expression-based association equations. Significant associations were seen in 27 unique methylation/expression pairs with expression-based, alternative, and combinatorial associations observed (10, 13, and 4 pairs, respectively). The majority of the predictive DNA methylation loci were located within CpG islands, and all but three of the locus pairs were negatively correlated with survival. This finding suggests that for most loci, methylation/expression pairs are inversely related, consistent with methylation-associated gene regulatory action. Our results indicate that changes in DNA methylation are associated with altered survival outcome through both coordinated changes in gene expression and alternative mechanisms. Furthermore, our approach offers an alternative method of biomarker discovery using a priori gene pairing and precise targeting to identify novel sites for locus-specific therapeutic intervention.

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.

Interleukin (IL)-31 activates signal transducer and activator of transcription (STAT)-1, STAT-5 and extracellular signal-regulated kinase 1/2 and down-regulates IL-12p40 production in activated human macrophages

BACKGROUND

Interleukin-31 is a cytokine expressed by activated T cells. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin. We recently showed that IL-31 induces pro-inflammatory cytokines following staphylococcal exotoxins' stimulation in human macrophages. However, signalling pathways of IL-31 in activated human macrophages still remain unclear. The aim of the study was to investigate the signalling pathways of IL-31 receptor as well as functional effects of IL-31 in activated macrophages.

METHODS

Human macrophages were prestimulated with staphylococcal exotoxins (SEB, α-toxin) to up-regulate the IL-31 receptor with and without IL-31. Phospho-signal transducer and activator of transcription (pSTAT) 1/3/5, phospho-extracellular signal-regulated kinase (ERK 1/2), β-actin as well as p21/WAF/Cip1 levels were determined by means of Western blot analysis. Interleukin-12p40, IL-12p70 and IL-23 secretions were assessed by using an enzyme-linked immunosorbent assay.

RESULTS

Interleukin-31 strongly activated STAT-1 and 5 but not STAT-3 in human macrophages after up-regulation of IL-31 receptor with staphylococcal exotoxins. p21/WAF/Cip1 expression was induced by IL-31 in activated human macrophages. Furthermore, IL-31 down-regulated. IL-12p40 secretion via ERK 1/2 phosphorylation in human macrophages following up-regulation of IL-31 receptor with staphylococcal exotoxins.

CONCLUSIONS

The T helper (Th) 2 cytokine IL-31 induces pro-inflammatory effects in activated human macrophages via STAT-1 and 5 phosphorylation. Interleukin-31-induced ERK 1/2 activation contributes to the underlying mechanism of Th1 cytokine IL-12 suppression in macrophages. This mechanism may be relevant in Th2 inflammatory responses and may help to develop therapeutic strategies in IL-31-associated diseases such as AD.

Increased frequencies of IL-31-producing T cells are found in chronic atopic dermatitis skin

Interleukin (IL)-31 has been associated with pruritus, a characteristic feature of atopic dermatitis (AD). Local T cell responses may be responsible for the increased level of IL-31 mRNA observed in AD. We investigated the frequency of IL-31-producing T cells in AD lesions, as well as their cytokine profile. T cells were isolated from chronic AD lesions, autologous blood and healthy donor skin. Intracellular expression of IL-31, IFN-γ, IL-13, IL-17 and IL-22 was measured using flow cytometry. T cells from AD lesions contained significantly higher percentages of IL-31-producing T cells compared to autologous blood and donor skin. Many IL-31-producing T cells co-produced IL-13 and to lesser extent IL-22, but rarely IFN-γ or IL-17. A substantial part of the IL-31-producing T cells did not co-produce any of the other cytokines and could therefore not be linked to any of the known functionally different T cell subsets. The T cell infiltrates were also relatively enriched for Th2/Tc2 and Th22/Tc22 cells, while frequencies of Th1/Tc1 and Th17 cells were decreased. This is the first report describing the detection of IL-31 at protein level in skin-infiltrating T cells. We show here that T cells in chronic AD skin produce IL-31 and that AD lesions contain increased levels of these IL-31-producing T cells. This suggests that a substantial part of previously reported increased IL-31 mRNA levels in AD skin is T cell derived and that these cells may be involved in the pathogenesis of AD.