Aysefa Doganci

The IL-6R α chain controls lung CD4+CD25+ Treg development and function during allergic airway inflammation in vivo

The cytokine IL-6 acts via a specific receptor complex that consists of the membrane-bound IL-6 receptor (mIL-6R) or the soluble IL-6 receptor (sIL-6R) and glycoprotein 130 (gp130). In this study, we investigated the role of IL-6R components in asthma. We observed increased levels of sIL-6R in the airways of patients with allergic asthma as compared to those in controls. In addition, local blockade of the sIL-6R in a murine model of late-phase asthma after OVA sensitization by gp130-fraction constant led to suppression of Th2 cells in the lung. By contrast, blockade of mIL-6R induced local expansion of Foxp3-positive CD4+CD25+ Tregs with increased immunosuppressive capacities. CD4+CD25+ but not CD4+CD25- lung T cells selectively expressed the IL-6R alpha chain and showed IL-6-dependent STAT-3 phosphorylation. Finally, in an in vivo transfer model of asthma in immunodeficient Rag1 mice, CD4+CD25+ T cells isolated from anti-IL-6R antibody-treated mice exhibited marked immunosuppressive and antiinflammatory functions. IL-6 signaling therefore controls the balance between effector cells and Tregs in the lung by means of different receptor components. Furthermore, inhibition of IL-6 signaling emerges as a novel molecular approach for the treatment of allergic asthma.

Pathological role of IL-6 in the experimental allergic bronchial asthma in mice

Although allergic asthma was described to be associated with the presence of mucosal T-helper (Th)2 cells, it is not entirely clear which factors are responsible for priming of T cells to differentiate into Th2 effector cells in this disease. Interleukin (IL)-6 has been recognized as important because it is secreted by cells of the innate immunity and induces the expansion of the Th2 effector cells, which are major players of the adaptive immune responses. Additionally, IL-6 released by dendritic cells (DCs) inhibits the suppressive function of CD4+CD25+ T-regulatory cells, thus inhibiting the peripheral tolerance. The signal transduction of IL-6 has recently taught us how this cytokine influences different aspects of the immune response, especially under pathological conditions. IL-6 can bind to the soluble IL-6R, increased after allergen challenge in asthmatic patients, and, through a mechanism called trans-signaling, induces proliferation of cells expressing the cognate receptor gp130. This mechanism appears to be used for proliferation by developed Th2 cells in the airways. In contrast, through the membrane-bound IL-6R, IL-6 controls CD4+CD25+ survival, as well as the initial stages of the Th2 cells development in the lung. These findings impact the establishment of new therapies for allergic diseases; indeed, blockade of the soluble IL-6R through the fusion protein gp130Fc reduces Th2 cells in the lung, and by blocking the membrane-bound Il-6R, anti-IL-6R antibody treatment induces the number of T-regulatory cells in the lung, thereby reducing the local number of CD4+ T-effector cells in experimental asthma.

IL-2 Receptor β-Chain Signaling Controls Immunosuppressive CD4+ T Cells in the Draining Lymph Nodes and Lung during Allergic Airway Inflammation In Vivo

IL-2 influences both survival and differentiation of CD4+ T effector and regulatory T cells. We studied the effect of i.n. administration of Abs against the α- and the β-chains of the IL-2R in a murine model of allergic asthma. Blockade of the β- but not the α-chain of the IL-2R after allergen challenge led to a significant reduction of airway hyperresponsiveness. Although both treatments led to reduction of lung inflammation, IL-2 signaling, STAT-5 phosphorylation, and Th2-type cytokine production (IL-4 and IL-5) by lung T cells, IL-13 production and CD4+ T cell survival were solely inhibited by the blockade of the IL-2R β-chain. Moreover, local blockade of the common IL-2R/IL-15R β-chain reduced NK cell number and IL-2 production by lung CD4+CD25+ and CD4+CD25− T cells while inducing IL-10- and TGF-β-producing CD4+ T cells in the lung. This cytokine milieu was associated with reduced CD4+ T cell proliferation in the draining lymph nodes. Thus, local blockade of the β-chain of the IL-2R restored an immunosuppressive cytokine milieu in the lung that ameliorated both inflammation and airway hyperresponsiveness in experimental allergic asthma. These findings provide novel insights into the functional role of IL-2 signaling in experimental asthma and suggest that blockade of the IL-2R β-chain might be useful for therapy of allergic asthma in humans.

Enhanced in vivo targeting of murine nonparenchymal liver cells with monophosphoryl lipid A functionalized microcapsules.

A broad spectrum of infectious liver diseases emphasizes the need of microparticles for targeted delivery of immunomodulatory substances to the liver. Microcapsules (MCs) are particularly attractive for innovative drug and vaccine formulations, enabling the combination of antigen, drugs, and adjuvants. The present study aimed to develop microcapsules characterized by an enhanced liver deposition and accelerated uptake by nonparenchymal liver cells (NPCs). Initially, two formulations of biodegradable microcapsules were synthesized from either hydroxyethyl starch (HES) or mannose. Notably, HES-MCs accumulated primarily in the liver, while mannose particles displayed a lung preference. Functionalization of HES-MCs with anti-CD40, anti-DEC205, and/or monophosphoryl lipid A (MPLA) enhanced uptake of MCs by nonparenchymal liver cells in vitro. In contrast, only MPLA-coated HES-MCs promoted significantly the in vivo uptake by NPCs. Finally, HES-MCs equipped with MPLA, anti-CD40, and anti-DEC205 induced the secretion of TNF-α, IL-6 by Kupffer cells (KCs), and IFN-γ and IL-12p70 by liver dendritic cells (DCs). The enhanced uptake and activation of KCs by MPLA-HES-MCs is a promising approach to prevent or treat infection, since KCs are exploited as an entry gate in various infectious diseases, such as malaria. In parallel, loading and activating liver DCs, usually prone to tolerance, bears the potential to induce antigen specific, intrahepatic immune responses necessary to prevent and treat infections affecting the liver.

Mucosal immunoregulation: transcription factors as possible therapeutic targets.

Much progress has been recently made with regard to our understanding of the mucosal immune system in health and disease. In particular, it has been shown that uncontrolled mucosal immune responses driven by lymphocytes or non-lymphoid cells may lead to immunological diseases such as allergy, hypersensitivity and inflammation. Thus, a more detailed understanding of mucosal immune regulation and decision making at mucosal surfaces is essential for a better understanding of mucosal immune responses in health and disease. Antigen presenting cells and T lymphocytes play a key role in controlling mucosal immune responses. To deal with this key task, T helper cells differentiate into functionally distinct subsets: TH1 (CD4+ T Helper cells), TH2, TH3, Tr1, and CD4+CD25+ T (Treg) cells. This review summarizes the role of antigen presenting cells, eosinophils, mast cells and T-cell subsets in the pathogenesis of allergic inflammation and intestinal inflammation. Furthermore, we discuss novel immunological treatment modalities for allergic inflammation (e.g. allergic asthma) and chronic intestinal inflammation (e.g. inflammatory bowel diseases (IBD)) such as the control of the expression of transcription factors to redirect pathological immune responses.

IL-27 improves migrational and antiviral potential of CB dendritic cells

Interleukin (IL)-27 is known to be increased considerably in cord blood (CB) dendritic cells (DCs) after TLR ligation. Previously, we demonstrated that also basal IL-27 levels are higher in CB DCs. Here, we examined effects of IL-27 on monocyte derived dendritic cells (moDCs) to approach its particular role in the specialized immune system of the human neonate. Exogenous IL-27 promotes IL-27 transcription in CB and adult blood (AB) moDCs. IL-27 acts on CB moDCs primarily by significantly augmenting IL-27 protein, secondarily by increasing transcription of CXCL10 among other chemokines, chemokine receptor CCR1, interferon stimulated genes, transcription factor IRF8 and genes involved in antigen presentation. Furthermore, CB moDCs respond to IL-27 with augmented IL-8 and Tumor necrosis factor (TNF)-α. The results suggest that IL-27 enhances migrational and antiviral properties of CB dendritic cells.

Inflammatory Characteristics of Monocytes from Pediatric Patients with Tuberous Sclerosis.

OBJECTIVE Therapeutic options for the tuberous sclerosis complex (TSC) syndrome showed varying outcomes. Malfunctional tsc1/tsc2 genes leave mTOR uninhibited, a positive downstream modulator of the innate proinflammatory immune system, which has not yet been described in pediatric patients with TSC. METHODS Using polymerase chain reaction (PCR) gene expression levels of monocytes after cultivation with lipopolysaccharide (LPS) or with LPS + mTOR inhibitor rapamycin, patients with TSC (n = 16) were compared with healthy subjects (n = 20). RESULTS Compared with monocytes from healthy controls, LPS showed a more prominent gene expression pattern in patients with TSC (CCL24, CXCL10, IL-6, IL-10, and IL-1B). Proinflammatory reactions against LPS were modulated by rapamycin. With LPS + rapamycin monocytes from patients with TSC showed gene expression patterns different from healthy subjects. Furthermore, developmental differences were discernible in patients with TSC, compared with gene expression levels for patients 0 to 5 years to those 6 to 11 years of age, the latter with marked expression of IL-6 IL-1A, IL-1B, RIPK2, but also IL-10. CONCLUSION The effects of LPS, even more of LPS with rapamycin on monocytes from patients with TSC suggested that inflammatory processes are distinct from those in healthy subjects. Furthermore, reaction to rapamycin indicates age-related gene expression levels. Our findings offer a model to decipher the unknown and varying gene expression pattern induced by rapamycin.

Microbiome analysis in a pediatric cohort of inflammatory bowel disease supports the rational of fecal microbiome therapy

Aims In recent years, the role of gut flora in inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn s Disease (CD) has become focus of intense research. The working hypothesis is that an altered microbiota causes mucosal inflammation in a genetically susceptible individual. Understanding the microbiota s role in the pathogenesis of the disease is essential for new IBD treatments aimed in shifting the intestinal bacterial flora back to a physiological homeostasis, particularly relevant for children not responding to conventional therapy.