Susetta Finotto

IL-6 signaling in autoimmunity, chronic inflammation and inflammation-associated cancer.

IL-6 activates various cell types carrying the membrane bound IL-6R (classical IL-6 signaling) as well as IL-6R(-) gp130(+) cells via the soluble IL-6R (IL-6 trans-signaling). IL-6 signaling plays a pivotal role in controlling the differentiation and activation of T lymphocytes by inducing the Jak/STAT-3 and the Ras/Erk/C/EBP pathways. In particular, IL-6 modulates the resistance of T cells against apoptosis, induces activation of T helper cells and controls the balance between regulatory T cells and Th17 cells. Importantly, recent findings suggest that blockade of IL-6 signaling is effective in treating experimental models of autoimmune and chronic inflammatory diseases such as inflammatory bowel diseases, diabetes, multiple sclerosis, asthma and rheumatoid arthritis as well as models of inflammation-associated cancer. Thus, anti-IL-6/anti-IL-6R strategies emerge as promising novel approaches for therapy of inflammatory diseases in humans. In this review article, we discuss the latest findings on the role of IL-6 in experimental models of autoimmunity and cancer, as well as clinical perspectives.

IL‐28A (IFN‐λ2) modulates lung DC function to promote Th1 immune skewing and suppress allergic airway disease

IL‐28 (IFN‐λ) cytokines exhibit potent antiviral and antitumor function but their full spectrum of activities remains largely unknown. Recently, IL‐28 cytokine family members were found to be profoundly down‐regulated in allergic asthma. We now reveal a novel role of IL‐28 cytokines in inducing type 1 immunity and protection from allergic airway disease. Treatment of wild‐type mice with recombinant or adenovirally expressed IL‐28A ameliorated allergic airway disease, suppressed Th2 and Th17 responses and induced IFN‐γ. Moreover, abrogation of endogenous IL‐28 cytokine function in IL‐28Rα−/− mice exacerbated allergic airway inflammation by augmenting Th2 and Th17 responses, and IgE levels. Central to IL‐28A immunoregulatory activity was its capacity to modulate lung CD11c+ dendritic cell (DC) function to down‐regulate OX40L, up‐regulate IL‐12p70 and promote Th1 differentiation. Consistently, IL‐28A‐mediated protection was absent in IFN‐γ−/− mice or after IL‐12 neutralization and could be adoptively transferred by IL‐28A‐treated CD11c+ cells. These data demonstrate a critical role of IL‐28 cytokines in controlling T cell responses in vivo through the modulation of lung CD11c+ DC function in experimental allergic asthma.

IL-10 and Regulatory T Cells Cooperate in Allergen-Specific Immunotherapy To Ameliorate Allergic Asthma

Human studies demonstrated that allergen-specific immunotherapy (IT) represents an effective treatment for allergic diseases. IT involves repeated administration of the sensitizing allergen, indicating a crucial contribution of T cells to its medicinal benefit. However, the underlying mechanisms of IT, especially in a chronic disease, are far from being definitive. In the current study, we sought to elucidate the suppressive mechanisms of IT in a mouse model of chronic allergic asthma. OVA-sensitized mice were challenged with OVA or PBS for 4 wk. After development of chronic airway inflammation, mice received OVA-specific IT or placebo alternately to airway challenge for 3 wk. To analyze the T cell–mediated mechanisms underlying IT in vivo, we elaborated the role of T-bet–expressing Th1 cells, T cell–derived IL-10, and Ag-specific thymic as well as peripherally induced Foxp3+ regulatory T (Treg) cells. IT ameliorated airway hyperresponsiveness and airway inflammation in a chronic asthma model. Of note, IT even resulted in a regression of structural changes in the airways following chronic inhaled allergen exposure. Concomitantly, IT induced Th1 cells, Foxp3+, and IL-10–producing Treg cells. Detailed analyses revealed that thymic Treg cells crucially contribute to the effectiveness of IT by promoting IL-10 production in Foxp3-negative T cells. Together with the peripherally induced Ag-specific Foxp3+ Treg cells, thymic Foxp3+ Treg cells orchestrate the curative mechanisms of IT. Taken together, we demonstrate that IT is effective in a chronic allergic disease and dependent on IL-10 and thymic as well as peripherally induced Ag-specific Treg cells.

A role for T-bet-mediated tumour immune surveillance in anti-IL-17A treatment of lung cancer

Lung cancer is the leading cause of cancer deaths worldwide. The cytokine interleukin-17A supports tumour vascularization and growth, however, its role in lung cancer is unknown. Here we show, in the lungs of patients with lung adenocarcinoma, an increase in interleukin-17A that is inversely correlated with the expression of T-bet and correlated with the T regulatory cell transcription factor Foxp3. Local targeting of interleukin-17A in experimental lung adenocarcinoma results in a reduction in tumour load, local expansion of interferon-γ-producing CD4(+) T cells and a reduction in lung CD4(+)CD25(+)Foxp3(+) regulatory T cells. T-bet((-/-)) mice have a significantly higher tumour load compared with wild-type mice. This is associated with the local upregulation of interleukin-23 and induction of interleukin-17A/interleukin-17R-expressing T cells infiltrating the tumour. Local anti-interleukin-17A antibody treatment partially improves the survival of T-bet((-/-)) mice. These results suggest that local anti-interleukin-17A antibody therapy could be considered for the treatment of lung tumours.

The TGF‐β‐inducible miR‐23a cluster attenuates IFN‐γ levels and antigen‐specific cytotoxicity in human CD8+ T cells

Cytokine secretion and degranulation represent key components of CD8+ T‐cell cytotoxicity. While transcriptional blockade of IFN‐γ and inhibition of degranulation by TGF‐β are well established, we wondered whether TGF‐β could also induce immune‐regulatory miRNAs in human CD8+ T cells. We used miRNA microarrays and high‐throughput sequencing in combination with qRT‐PCR and found that TGF‐β promotes expression of the miR‐23a cluster in human CD8+ T cells. Likewise, TGF‐β up‐regulated expression of the cluster in CD8+ T cells from wild‐type mice, but not in cells from mice with tissue‐specific expression of a dominant‐negative TGF‐β type II receptor. Reporter gene assays including site mutations confirmed that miR‐23a specifically targets the 3′UTR of CD107a/LAMP1 mRNA, whereas the further miRNAs expressed in this cluster—namely, miR‐27a and ‐24—target the 3′UTR of IFN‐γ mRNA. Upon modulation of the miR‐23a cluster by the respective miRNA antagomirs and mimics, we observed significant changes in IFN‐γ expression, but only slight effects on CD107a/LAMP1 expression. Still, overexpression of the cluster attenuated the cytotoxic activity of antigen‐specific CD8+ T cells. These functional data thus reveal that the miR‐23a cluster not only is induced by TGF‐β, but also exerts a suppressive effect on CD8+ T‐cell effector functions, even in the absence of TGF‐β signaling.

Induction of tolerogenic lung CD4+ T cells by local treatment with a pSTAT-3 and pSTAT-5 inhibitor ameliorated experimental allergic asthma

Signal transducer and activator of transcription (STAT)-3 inhibitors play an important role in regulating immune responses. Galiellalactone (GL) is a fungal secondary metabolite known to interfere with the binding of phosphorylated signal transducer and activator of transcription (pSTAT)-3 as well of pSTAT-6 dimers to their target DNA in vitro. Intra nasal delivery of 50 μg GL into the lung of naive Balb/c mice induced FoxP3 expression locally and IL-10 production and IL-12p40 in RNA expression in the airways in vivo. In a murine model of allergic asthma, GL significantly suppressed the cardinal features of asthma, such as airway hyperresponsiveness, eosinophilia and mucus production, after sensitization and subsequent challenge with ovalbumin (OVA). These changes resulted in induction of IL-12p70 and IL-10 production by lung CD11c(+) dendritic cells (DCs) accompanied by an increase of IL-3 receptor α chain and indoleamine-2,3-dioxygenase expression in these cells. Furthermore, GL inhibited IL-4 production in T-bet-deficient CD4(+) T cells and down-regulated the suppressor of cytokine signaling-3 (SOCS-3), also in the absence of STAT-3 in T cells, in the lung in a murine model of asthma. In addition, we found reduced amounts of pSTAT-5 in the lung of GL-treated mice that correlated with decreased release of IL-2 by lung OVA-specific CD4(+) T cells after treatment with GL in vitro also in the absence of T-bet. Thus, GL treatment in vivo and in vitro emerges as a novel therapeutic approach for allergic asthma by modulating lung DC phenotype and function resulting in a protective response via CD4(+)FoxP3(+) regulatory T cells locally.

SFTA3, a novel protein of the lung: three-dimensional structure, characterisation and immune activation

The lung constantly interacts with numerous pathogens. Thus, complex local immune defence mechanisms are essential to recognise and dispose of these intruders. This work describes the detection, characterisation and three-dimensional structure of a novel protein of the lung (surfactant-associated protein 3 (SFTA3/SP-H)) with putative immunological features. Bioinformatics, biochemical and immunological methods were combined to elucidate the structure and function of SFTA3. The tissue-specific detection and characterisation was performed by using electron microscopy as well as fluorescence imaging. Three-dimensional structure generation and analysis led to the development of specific antibodies and, as a consequence, to the localisation of a novel protein in human lung under consideration of cystic fibrosis, asthma and sepsis. In vitro experiments revealed that lipopolysaccharide induces expression of SFTA3 in the human lung alveolar type II cell line A549. By contrast, the inflammatory cytokines interleukin (IL)-1&bgr; and IL-23 inhibit expression of SFTA3 in A549. Sequence- and structure-based prediction analysis indicated that the novel protein is likely to belong to the family of lung surfactant proteins. The results suggest that SFTA3 is an immunoregulatory protein of the lung with relevant protective functions during inflammation at the mucosal sites. SFTA3: a novel lung protein with putative protective and immunological functions during inflammation in lung diseases http://ow.ly/tsnne

The emerging role of T cell cytokines in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is among the most frequent types of cancer and associated with significant mortality. Recent studies suggest that tumor infiltrating T lymphocytes and their immunoregulatory cytokines play a fundamental role in controlling tumor growth and metastasis. Whereas T helper 1 cells and their master transcription factor T-bet have been identified as important regulators of IFN-gamma driven anti-tumoral immune response, IL-17 producing T helper 17 cells expressing RORA/C transcription factors have been found to augment tumor growth and cell proliferation in NSCLC. Furthermore, regulatory T cells were shown to impair immune responses against lung cancer. As modulation of T cell cytokines such as IL-17A has been recently shown to suppress tumor growth in experimental models, anti-cytokine agents emerge as a promising new approach for treatment of lung cancer.

Increased immunosuppressive function of CD4(+)CD25(+)Foxp3(+)GITR+ T regulatory cells from NFATc2((-/-)) mice controls allergen-induced experimental asthma.

The expansion of effector T cells is tightly controlled by transcription factors like nuclear factor of activated T cells (NFAT) family members that mediate early intracellular responses to T cell receptor-mediated signals. In this study we show that, after allergen challenge, NFATc2((-/-)) mice had augmented number of functionally intact CD4(+)CD25(++)GITR(++) T regulatory (T regs) cells in the lung. Anti-GITR antibody treatment inhibited T regulatory cell function and enhanced the number of activated lung CD4(+) T cells associated with increased IL-2 and pSTAT-5 in the airways of NFATc2((-/-)) mice in experimental allergic asthma. This agonistic treatment led to increased inflammation in the lung of NFATc2((-/-)) treated mice. These data indicate that NFATc2((-/-)) mice have increased number of CD4(+)CD25(+)Foxp3(+) T regulatory cells with induced immunosuppressive function that control allergen-induced experimental asthma.

Th9 and other IL-9-producing cells in allergic asthma.

Allergic asthma is a worldwide increasing chronic disease of the airways which affects more than 300 million people. It is associated with increased IgE, mast cell activation, airway hyperresponsiveness (AHR), mucus overproduction and remodeling of the airways. Previously, this pathological trait has been associated with T helper type 2 (Th2) cells. Recently, different CD4+ T cell subsets (Th17, Th9) as well as cells of innate immunity, like mast cells and innate lymphoid cells type 2 (ILC2s), which are all capable of producing the rediscovered cytokine IL-9, are known to contribute to this disease. Regarding Th9 cells, it is known that naïve T cells develop into IL-9-producing cells in the presence of interleukin-4 (IL-4) and transforming growth factor beta (TGFβ). Downstream of IL-4, several transcription factors like signal transducer and activator of transcription 6 (STAT6), interferon regulatory factor 4 (IRF4), GATA binding protein 3 (GATA3), basic leucine zipper transcription factor, ATF-like (BATF) and nuclear factor of activated T cells (NFAT) are activated. Additionally, the transcription factor PU.1, which is downstream of TGFβ signaling, also seems to be crucial in the development of Th9 cells. IL-9 is a pleiotropic cytokine that influences various distinct functions of different target cells such as T cells, B cells, mast cells and airway epithelial cells by activating STAT1, STAT3 and STAT5. Because of its pleiotropic functions, IL-9 has been demonstrated to be involved in several diseases, such as cancer, autoimmunity and other pathogen-mediated immune-regulated diseases. In this review, we focus on the role of Th9 and IL-9-producing cells in allergic asthma.