Secretion of interleukin-1 receptor antagonist from human mast cells after immunoglobulin E-mediated activation and after segmental antigen challenge

Bronchial epithelial transcriptomics and experimental validation reveal asthma severity-related neutrophilc signatures and potential treatments

Airway epithelial transcriptome analysis of asthma patients with different severity was used to disentangle the immune infiltration mechanisms affecting asthma exacerbation, which may be advantageous to asthma treatment. Here we introduce various bioinformatics methods and develop two models: an OVA/CFA-induced neutrophil asthma mouse model and an LPS-induced human bronchial epithelial cell damage model. Our objective is to investigate the molecular mechanisms, potential targets, and therapeutic strategies associated with asthma severity. Multiple bioinformatics methods identify meaningful differences in the degree of neutrophil infiltration in asthma patients with different severity. Then, PTPRC, TLR2, MMP9, FCGR3B, TYROBP, CXCR1, S100A12, FPR1, CCR1 and CXCR2 are identified as the hub genes. Furthermore, the mRNA expression of 10 hub genes is determined in vivo and in vitro models. Reperixin is identified as a pivotal drug targeting CXCR1, CXCR2 and MMP9. We further test the potential efficiency of Reperixin in 16HBE cells, and conclude that Reperixin can attenuate LPS-induced cellular damage and inhibit the expression of them. In this study, we successfully identify and validate several neutrophilic signatures and targets associated with asthma severity. Notably, Reperixin displays the ability to target CXCR1, CXCR2, and MMP9, suggesting its potential therapeutic value for managing deteriorating asthma.

Interleukin-1 receptor antagonist: An alternative therapy for cancer treatment

The interleukin-1 receptor antagonist (IL-1Ra) is an anti-inflammatory cytokine and a naturally occurring antagonist of the IL-1 receptor. It effectively counteracts the IL-1 signaling pathway mediated by IL-1α/β. Over the past few decades, accumulating evidence has suggested that IL-1 signaling plays an essential role in tumor formation, growth, and metastasis. Significantly, anakinra, the first United States Food and Drug Administration (FDA)-approved IL-1Ra drug, has demonstrated promising antitumor effects in animal studies. Numerous clinical trials have subsequently incorporated anakinra into their cancer treatment protocols. In this review, we comprehensively discuss the research progress on the role of IL-1 in tumors and summarize the significant contribution of IL-1Ra (anakinra) to tumor immunity. Additionally, we analyze the potential value of IL-1Ra as a biomarker from a clinical perspective. This review is aimed to highlight the important link between inflammation and cancer and provide potential drug targets for future cancer therapy.

Divergent Mast Cell Responses Modulate Antiviral Immunity During Influenza Virus Infection

Influenza A virus (IAV) is a respiratory pathogen that infects millions of people each year. Both seasonal and pandemic strains of IAV are capable of causing severe respiratory disease with a high risk of respiratory failure and opportunistic secondary infection. A strong inflammatory cytokine response is a hallmark of severe IAV infection. The widespread tissue damage and edema in the lung during severe influenza is largely attributed to an overexuberant production of inflammatory cytokines and cell killing by resident and infiltrating leukocytes. Mast cells (MCs) are a sentinel hematopoietic cell type situated at mucosal sites, including the lung. Poised to react immediately upon detecting infection, MCs produce a vast array of immune modulating molecules, including inflammatory cytokines, chemokines, and proteases. As such, MCs have been implicated as a source of the immunopathology observed in severe influenza. However, a growing body of evidence indicates that MCs play an essential role not only in inducing an inflammatory response but in suppressing inflammation as well. MC-derived immune suppressive cytokines are essential to the resolution of a number of viral infections and other immune insults. Absence of MCs prolongs infection, exacerbates tissue damage, and contributes to dissemination of the pathogen to other tissues. Production of cytokines such as IL-10 and IL-6 by MCs is essential for mitigating the inflammation and tissue damage caused by innate and adaptive immune cells alike. The two opposing functions of MCs-one pro-inflammatory and one anti-inflammatory-distinguish MCs as master regulators of immunity at the site of infection. Amongst the first cells to respond to infection or injury, MCs persist for the duration of the infection, modulating the recruitment, activation, and eventual suppression of other immune cells. In this review, we will discuss the immune modulatory roles of MCs over the course of viral infection and propose that the immune suppressive mediators produced by MCs are vital to minimizing immunopathology during influenza infection.

Interferon α2 and interferon γ induce the degranulation independent production of VEGF-A and IL-1 receptor antagonist and other mediators from human mast cells

Background

Mast cells are resident immune effector cells, often studied in the context of allergic disease. Found in substantial numbers at sites of potential infection they are increased at sites of angiogenesis and can be pivotal for the sensing and clearance of a variety of pathogens. Interferons (IFNs) are cytokines that are critical for host defence against intracellular pathogens. Increased levels of IFNs are observed during viral infection and in autoimmune diseases. IFNs are also widely used therapeutically and have been examined in the therapy of severe asthma.

Objective

To define the selective human mast cell cytokine and chemokine response following activation with type I or type II IFN's.

Methods

The ability of both IFNα2 and IFNγ to induce cytokine production by human cord blood‐derived mast cells was examined in vitro. Cytokine and chemokine production at 6 and 24 h was assessed by multiplex protein analysis. Degranulation was assessed by β‐hexosaminidase release. Mast cells were also treated with reovirus or respiratory syncytial virus and their production of CXCL10, IL‐1 receptor antagonist (IL‐1Ra), and vascular endothelial growth factor (VEGF) examined after 24 h.

Results

In addition to increased expression of classical IFN response genes, such as CXCL10, small but significant increases in CCL5 and IL‐17 production were observed following IFN activation. Notably, human mast cells produced both VEGF and IL‐1Ra in a dose dependent manner. These responses occurred in the absence of mast cell degranulation by a mechanism consistent with classical IFN signaling. Both reovirus and respiratory syncytial virus infection of mast cells, were also associated with IFN‐dependent IL‐1Ra expression.

Conclusion and Clinical Relevance

Our findings demonstrate that IFNs have profound impact on cytokine and chemokine expression by human mast cells, alone or in the context of viral infection. Mast cell VEGF and IL‐1Ra responses to IFNs could impact the regulation of local inflammatory responses and subsequent tissue remodeling.

Differential association of plasma monocyte chemoattractant protein-1 with systemic inflammatory and airway remodeling biomarkers in type-2 diabetic patients with and without asthma

BACKGROUND

Chronic inflammation is a hallmark of type-2 diabetes (T2D) and asthma. Monocyte chemoattractant protein (MCP)-1 or CCL-2 is a key regulator of monocytic infiltration into the sites of inflammation. The changes in systemic MCP-1 levels and its relationship with other inflammatory/immune markers in T2D patients with asthma remain unclear and have been addressed in this study.

METHODS

Plasma samples from 10 asthmatic T2D patients (Group I: BMI = 37.82 ± 9.75 kg/m²), 13 non-asthmatic T2D patients (Group II: BMI = 32.68 ± 4.63 kg/m²), 23 asthma patients without T2D (Group III: BMI = 30.14 ± 6.74 kg/m²), and 25 non-asthmatic non-diabetic controls (Group IV: BMI = 27.99 ± 5.86 kg/m²) were used to measure levels of MCP-1 and multiple cytokine/chemokine biomarkers with bead-based multiplex assays using Luminex technology. IgE/ECP were measured using commercial ELISA kits. Data (mean ± SEM) were compared using unpaired Student's t-test and linear dependence between two variables was assessed by Pearson's correlation coefficient (r) and P ≤ 0.05 was considered as significant.

RESULTS

Plasma MCP-1 levels were significantly higher in Group I (337.95 ± 46.40 pg/mL) as compared with Group II (216.69 ± 17.30 pg/mL), Group III (251.76 ± 19.80 pg/mL), and Group IV (223.52 ± 133.36 pg/mL). MCP-1 showed differential association with tested biomarkers by correlating positively with: (i) IFN-α2, IL-10, fractalkine, and VEGF in T2D patients with asthma; (ii) IL-6 and GRO-α in T2D patients without asthma; (iii) MDC, IP-10, GM-CSF, FGF-2, and PDGF-AA/BB in patients with asthma only; and (iv) FPG and TG in non-asthmatic non-diabetic controls. MCP-1 associated with IL-1RA only in subjects with asthma.

CONCLUSION

The systemic MCP-1 levels were significantly elevated in T2D patients with asthma as compared with those without asthma and/or diabetes while these changes correlated differentially with important biomarkers of inflammation and airway remodeling.

Activated mast cells synthesize and release soluble ST2-a decoy receptor for IL-33

IL-33 released from damaged cells plays a central role in allergic inflammation by acting through its membrane-bound receptor, ST2 receptor (ST2L). IL-33 activity can be neutralized by the soluble spliced variant of ST2 (sST2) that has been associated with allergic inflammation but its source is not well defined. We investigated whether mast cells (MCs) are a significant source of sST2 following activation through FcεRI or ST2. We find that antigen and IL-33 induce substantial production and release of sST2 from human and mouse MCs in culture and do so synergistically when added together or in combination with stem cell factor. Moreover, increases in circulating sST2 during anaphylaxis in mice were dependent on the presence of MCs. Human MCs activated via FcεRI failed to generate IL-33 and IL-33 produced by mouse bone marrow-derived MCs was retained within the cells. Therefore, FcεRI-mediated sST2 production is independent of MC-derived IL-33 acting in an autocrine manner. These results are consistent with the conclusion that both mouse and human MCs when activated are a significant inducible source of sST2 but not IL-33 and thus have the ability to modulate the biologic impact of IL-33 produced locally by other cell types during allergic inflammation.

Potential effector and immunoregulatory functions of mast cells in mucosal immunity

Mast cells (MCs) are cells of hematopoietic origin that normally reside in mucosal tissues, often near epithelial cells, glands, smooth muscle cells, and nerves. Best known for their contributions to pathology during IgE-associated disorders such as food allergy, asthma, and anaphylaxis, MCs are also thought to mediate IgE-associated effector functions during certain parasite infections. However, various MC populations also can be activated to express functional programs--such as secreting preformed and/or newly synthesized biologically active products--in response to encounters with products derived from diverse pathogens, other host cells (including leukocytes and structural cells), damaged tissue, or the activation of the complement or coagulation systems, as well as by signals derived from the external environment (including animal toxins, plant products, and physical agents). In this review, we will discuss evidence suggesting that MCs can perform diverse effector and immunoregulatory roles that contribute to homeostasis or pathology in mucosal tissues.

The multifaceted effects of polysaccharides isolated from Dendrobium huoshanense on immune functions with the induction of interleukin-1 receptor antagonist (IL-1ra) in monocytes

Dendrobium huoshanense is a valuable and versatile Chinese herbal medicine with the anecdotal claims of cancer prevention and anti-inflammation. However, its immunological activities are limited to in vitro studies on a few cytokines and immune cell functions. First, we investigated the effects of polysaccharides isolated from DH (DH-PS) on inducing a panel of cytokines/chemokines in mice in vivo and human in vitro. We found that DH polysaccharides (DH-PS) induced TH1, TH2, inflammatory cytokines and chemokines in mouse in vivo and human cells in vitro. Secondly, we demonstrated that DH-PS expanded mouse splenocytes in vivo including CD4⁺ T cells, CD8⁺ T cells, B cells, NK cells, NKT cells, monocytes/macrophages, granulocytes and regulatory T cells. Notably, DH-PS induced an anti-inflammatory molecule, IL-1ra, in mouse and human immune cells, especially monocytes. The serum level of IL-1ra elicited by the injection of DH-PS was over 10 folds of IL-1β, suggesting that DH-PS-induced anti-inflammatory activities might over-ride the inflammatory ones mediated by IL-1β. The signaling pathways of DH-PS-induced IL-1ra production was shown to involve ERK/ELK, p38 MAPK, PI3K and NFκB. Finally, we observed that IL-1ra level induced by DH-PS was significantly higher than that by F3, a polysaccharide extract isolated from another popular Chinese herbal medicine, Ganoderma lucidum. These results indicated that DH-PS might have potential applications for ameliorating IL-1-induced pathogenic conditions.

Targeting mast cells in inflammatory diseases

Although mast cells have long been known to play a critical role in anaphylaxis and other allergic diseases, they also participate in some innate immune responses and may even have some protective functions. Data from the study of mast cell-deficient mice have facilitated our understanding of some of the molecular mechanisms driving mast cell functions during both innate and adaptive immune responses. This review presents an overview of the biology of mast cells and their potential involvement in various inflammatory diseases. We then discuss some of the current pharmacological approaches used to target mast cells and their products in several diseases associated with mast cell activation.

Mast cell regulation of the immune response

Mast cells are well known as principle effector cells of type I hypersensitivity responses. Beyond this role in allergic disease, these cells are now appreciated as playing an important role in many inflammatory conditions. This review summarizes the support for mast cell involvement in resisting bacterial infection, exacerbating autoimmunity and atherosclerosis, and promoting cancer progression. A commonality in these conditions is the ability of mast cells to elicit migration of many cell types, often through the production of inflammatory cytokines such as tumor necrosis factor. However, recent data also demonstrates that mast cells can suppress the immune response through interleukin-10 production. The data encourage those working in this field to expand their view of how mast cells contribute to immune homeostasis.

Mast cells and mastocytosis

Mast cells have been recognized for well over 100 years. With time, human mast cells have been documented to originate from CD34+ cells, and have been implicated in host responses in both innate and acquired immunity. In clinical immunology, they are recognized for their central role in IgE-mediated degranulation and allergic inflammation by virtue of their expression of the high-affinity receptor for IgE and release of potent proinflammatory mediators. In hematology, the clinical disease of mastocytosis is characterized by a pathologic increase of mast cells in tissues, often associated with mutations in KIT, the receptor for stem cell factor. More recently, and with increased understanding of how human mast cells are activated through receptors including the high-affinity receptor for IgE and KIT, specific tyrosine kinase inhibitors have been identified with the potential to interrupt signaling pathways and thus limit the proliferation of mast cells as well as their activation through immunoglobulin receptors.

Safety of segmental allergen challenge in human allergic asthma

BACKGROUND

Segmental allergen challenge is widely used to study mechanisms of human allergic asthma. Despite the relatively large dissemination, limited information is available about the safety of this method.

OBJECTIVE

Observational, retrospective study to report the adverse events of segmental allergen challenge in a large group of volunteers with asthma.

METHODS

In total, 78 cases from several studies performed between 1994 and 2007 were pooled for this analysis. Volunteers underwent allergen challenge using either a fixed dose of allergen (7 cases) or an individually standardized allergen dose defined by an inhaled allergen test before the challenge (71 cases). A subgroup of 13 volunteers underwent repeated challenges, with more than 6 months between the challenges.

RESULTS

With a fixed dose instilled during bronchoscopy, 43% of the participants developed wheezing and coughing, requiring 2-6 puffs of a ss(2)-agonist after segmental allergen challenge. In volunteers with individually standardized doses, a ss(2)-agonist was required in only 19% of the cases. No severe adverse events occurred in all cases studied. Volunteers who underwent repeated challenges did not develop more adverse events than those who underwent 1 challenge.

CONCLUSIONS

Segmental allergen challenge is a safe tool to study the mechanisms of human allergic asthma, even when repeated challenges are performed in the same patient. It is associated with only a few, tolerable adverse events, especially when the dose of allergen is standardized individually.

IL-1 receptor antagonist in metabolic diseases: Dr Jekyll or Mr Hyde?

Interleukin-1 receptor antagonist (IL-1ra) has been shown to play a crucial role in the prevention of various inflammatory diseases. There is also convincing evidence that IL-1ra is able to counteract inflammatory effects of IL-1 members implicated in insulin resistance and diabetes. However, the use of knock-out animal models provides evidence to the contrary and the role of IL-1ra in obesity-linked anomalies remains controversial. This minireview gets an insight into recent findings on the implication of IL-1ra and its gene polymorphism in diabetes and obesity, discusses the potential dual effects of IL-1ra observed in different models, and comments on future directions.

Soluble CD23 and interleukin-1 receptor antagonist in human asthmatics following antigen challenge

Two postulated intrinsic anti-inflammatory mechanisms in asthma include the low affinity IgE receptor, or CD23, and interleukin 1 receptor antagonist (IL-1ra). We investigated the role these mediators play in the asthmatic response by measuring local levels in human asthmatics before and after segmental allergen challenge and examined the effect of inhaled corticosteroids on soluble CD23 and IL-1ra levels. Ten subjects underwent bronchoscopy at baseline and 24 hours after antigen challenge. Prior to challenge and every 12 hours afterward subjects received beclomethasone 252 microg or placebo. Fluid was analyzed for sCD23 and IL-1ra using ELISA immunoassays. Eosinophil percentages significantly increased at 24 hours following antigen challenge. sCD23 levels were generally undetectable at baseline and increased significantly following antigen challenge. IL-1ra levels increased 28-fold in the late-phase response. Beclomethasone significantly reduced the late-phase eosinophil percentage at 24 hours compared with placebo but did not attenuate late-phase sCD23 or IL-1ra levels. Our data showed a significant rise in the levels of two mediators thought to play an important role in the attenuation of the asthmatic response. The finding that steroid treatment did not enhance these levels suggests that this may be an independent approach to asthma therapy that should be investigated.

High-resolution tracking of cell division demonstrates differential effects of TH1 and TH2 cytokines on SCF-dependent human mast cell production in vitro: correlation with apoptosis and Kit expression

T-helper 1 (TH1) (interferon-gamma [IFN-gamma]) and TH2 (interleukin-4 [IL-4] and IL-5) cytokines have been variably reported to alter human mast cell numbers in complex culture systems. The effects of these cytokines on the kinetics of cell division and cell death are unknown, and their effect on mast cell behavior is relevant to anticipate the consequences of in vivo strategies that alter cytokine levels. To determine the effect of these cytokines on stem cell factor (SCF)-dependent human mast cell production, we used high-resolution tracking of cell division and correlated the results with cell apoptosis, expression of Kit, and mast cell degranulation. When IFN-gamma, IL-5, or IL-4 was administered over 8 weeks, we found each cytokine decreased the mast number through a different mechanism. IFN-gamma inhibited early progenitor cell division, IL-4 down-regulated early Kit expression, and IL-5 blocked later cell division. Further, IL-4 and IFN-gamma had the greatest suppressive effect on degranulation and FcepsilonRI expression. When these cytokines were administered to mature mast cells, IFN-gamma and IL-5 had no effect on degranulation and cell division, but IL-4 induced division and potentiated FcepsilonRI-mediated degranulation. Thus, exposure of human mast cells to IL-4, IL-5, and IFN-gamma during growth and differentiation generally down-regulated mast cell number and function, whereas IL-4 increased mature mast cell division and degranulation.

4. IgE, mast cells, basophils, and eosinophils

IgE, mast cells, basophils, and eosinophils constitute essential elements in allergic inflammation. Allergen-specific IgE, synthesized in response to allergens in the environment and in susceptible individuals, becomes fixed to high-affinity receptors on cellular membranes, especially of mast cells and basophils. If these receptor-bound IgE molecules are aggregated on reexposure to specific allergen, these mast cells and basophils produce mediators that result in the allergic response. Principal among the cells drawn to sites of mediator release is the eosinophil.