Analysis of novel disease-related genes in bronchial asthma

Bronchial asthma is a complex disease characterized by airway inflammation involving interleukin (IL)-4 and IL-13. We have applied microarray analyses to human bronchial epithelial cultures to probe for genes regulated by these cytokines and have identified a subset of disease-relevant genes by comparison with cDNA libraries derived from normal and asthmatic bronchial biopsies. Squamous cell carcinoma antigen-1 (SCCA1) and SCCA2, the cysteine and serine protease inhibitors, respectively, showed the highest expression by IL-4 and IL-13, and particularly, SCCA1 was significantly increased in the asthmatic cDNA library. STAT6 was shown to be involved in expression of SCCA1 and SCCA2 in vitro. Furthermore, serum levels of SCCA were also elevated in asthmatic patients. Taken together, it was supposed that SCCA may play some role in the pathogenesis of bronchia asthma, and measuring its serum level may be relevant for diagnosing or monitoring the status of bronchial asthma. In a complex disorder such as asthma, this combination of in vitro and in vivo genomic approaches is a powerful discriminatory method enabling identification of novel disease-related genes and their mechanisms of regulation.     

Anti-inflammatory effects of Tat-Annexin protein on ovalbumin-induced airway inflammation in a mouse model of asthma

Chronic airway inflammation is a key feature of bronchial asthma. Annexin-1 (ANX1) is an anti-inflammatory protein that is an important modulator and plays a key role in inflammation. Although the precise action of ANX1 remains unclear, it has emerged as a potential drug target for inflammatory diseases such as asthma. To examine the protective effects of ANX1 protein on ovalbumin (OVA)-induced asthma in animal models, we used a cell-permeable Tat-ANX1 protein. Mice sensitized and challenged with OVA antigen had an increased amount of cytokines and eosinophils in their bronchoalveolar lavage (BAL) fluid. However, administration of Tat-ANX1 protein before OVA challenge significantly decreased the levels of cytokines (interleukin (IL)-4, IL-5, and IL-13) and BAL fluid in lung tissues. Furthermore, OVA significantly increased the activation of mitogen-activated protein kinase (MAPK) in lung tissues, whereas Tat-ANX1 protein markedly reduced phosphorylation of MAPKs such as extracellular signal-regulated protein kinase, p38, and stress-activated protein kinase/c-Jun N-terminal kinase. These results suggest that transduced Tat-ANX1 protein may be a potential protein therapeutic agent for the treatment of lung disorders including asthma.     

Pendrin function in airway epithelia

The expression and function of the anion exchanger pendrin (SLC26A4) was thought to be limited mainly to the inner ear, kidney and thyroid. Recent data indicates that pendrin is also expressed in the bronchial epithelium following exposure to the T(H)2-type cytokines, interleukin (IL)-4 and IL-13. Expression of the transporter is also upregulated in bronchial asthma and chronic obstructive pulmonary disease. Both diseases involve respiratory inflammation leading to tissue destruction/remodeling and decreased airway function, and data so far indicate that increased pendrin expression and/or activity might contribute to their pathogenesis. In this review, we summarize data that have emerged within the past years aimed at revealing the role for pendrin in the airway epithelia.     

Bee venom ameliorates ovalbumin induced allergic asthma via modulating CD4+CD25+ regulatory T cells in mice

Asthma is a potentially life-threatening inflammatory disease of the lung characterized by the presence of large numbers of CD4⁺ T cells. These cells produce the Th2 and Th17 cytokines that are thought to orchestrate the inflammation associated with asthma. Bee venom (BV) has traditionally been used to relieve pain and to treat chronic inflammatory diseases. Recent reports have suggested that BV might be an effective treatment for allergic diseases. However, there are still unanswered questions related to the efficacy of BV therapy in treating asthma and its therapeutic mechanism. In this study, we evaluated whether BV could inhibit asthma and whether BV inhibition of asthma could be correlated with regulatory T cells (Treg) activity. We found that BV treatment increased Treg populations and suppressed the production of Th1, Th2 and Th17-related cytokines in an in vitro culture system, including IL2, IL4, and IL17. Interestingly, production of IL10, an anti-inflammatory cytokine secreted by Tregs, was significantly augmented by BV treatment. We next evaluated the effects of BV treatment on allergic asthma in an ovalbumin (OVA)-induced mouse model of allergic asthma. Cellular profiling of the bronchoalveolar lavage (BAL) and histopathologic analysis demonstrated that peribronchial and perivascular inflammatory cell infiltrates were significantly lowered following BV treatment. BV also ameliorated airway hyperresponsiveness, a hallmark symptom of asthma. In addition, IL4 and IL13 levels in the BAL fluid were decreased in the BV treated group. Surprisingly, the beneficial effects of BV treatment on asthma were eradicated following Treg depletion by anti-CD25 antibody injection, suggesting that the major therapeutic targets of BV were Tregs. These results indicate that BV efficiently diminishes bronchial inflammation in an OVA-induced allergic asthma murine model, and that this effect might correlate with Tregs, which play an important role in maintaining immune homeostasis and suppressing the function of other T cells to limit the immune response. These results also suggest that BV has potential therapeutic value for controlling allergic asthma responses.     

Cytokine-directed therapies for the treatment of chronic airway diseases

Multiple cytokines play a critical role in orchestrating and perpetuating inflammation in asthma and chronic obstructive pulmonary disease (COPD) and several specific cytokine and chemokine inhibitors now in development as future therapy for these diseases. Anti-IL-5 antibody markedly reduces peripheral blood and airway eosinophils, but does not appear to be effective in symptomatic asthma. Inhibition of IL-4 despite promising early results in asthma has been discontinued and blocking IL-13 might be more effective. Inhibitory cytokines, such as IL-10, interferons and IL-12 are less promising, as systemic delivery produces side effects. Inhibition of TNF-alpha may be useful in severe asthma and for treating severe COPD with systemic features. Many chemokines are involved in the inflammatory response of asthma and COPD and several small molecule inhibitors of chemokine receptors (CCR) are in development. CCR3 antagonists (which block eosinophil chemotaxis) and CXCR2 antagonists (which block neutrophil and monocyte chemotaxis) are in clinical development for asthma and COPD, respectively. Because so many cytokines are involved in asthma, drugs that inhibit the synthesis of multiple cytokines may prove to be more useful; several such classes of drug are now in clinical development and any risk of side effects with these non-specific inhibitors may be reduced by the inhaled route.     

Anti-inflammatory effects of the neurotransmitter agonist Honokiol in a mouse model of allergic asthma

Chronic airway inflammation is a hallmark of asthma, an immune-based disease with great societal impact. Honokiol (HNK), a phenolic neurotransmitter receptor (γ-aminobutyric acid type A) agonist purified from magnolia, has anti-inflammatory properties, including stabilization of inflammation in experimentally induced arthritis. The present study tested the prediction that HNK could inhibit the chronic inflammatory component of allergic asthma. C57BL/6 mice sensitized to and challenged with OVA had increased airway hyperresponsiveness to methacholine challenge and eosinophilia compared with naive controls. HNK-treated mice showed a reduction in airway hyperresponsiveness as well as a significant decrease in lung eosinophilia. Histopathology studies revealed a marked drop in lung inflammation, goblet cell hyperplasia, and collagen deposition with HNK treatment. Ag recall responses from HNK-treated mice showed decreased proinflammatory cytokines in response to OVA, including TNF-α-, IL-6-, Th1-, and Th17-type cytokines, despite an increase in Th2-type cytokines. Regulatory cytokines IL-10 and TGF-β were also increased. Assessment of lung homogenates revealed a similar pattern of cytokines, with a noted increase in the number of FoxP3(+) cells in the lung. HNK was able to alter B and T lymphocyte cytokine secretion in a γ-aminobutyric acid type A-dependent manner. These results indicate that symptoms and pathology of asthma can be alleviated even in the presence of increased Th2 cytokines and that neurotransmitter agonists such as HNK have promise as a novel class of anti-inflammatory agents in the treatment of chronic asthma.     

Personalized medicine with biologics for severe type 2 asthma: current status and future prospects

Asthma affects more than 300 million people worldwide and poses a large socioeconomic burden, particularly in the 5% to 10% of severe asthmatics. So far, each entry of new biologics in clinical trials has led to high expectations for treating all severe asthma forms, but the outcome has only been successful if the biologic, as add-on treatment, targeted specific patient subgroups. Indeed, we now realize that asthma is a heterogeneous disease with multiple phenotypes, based on distinct pathophysiological mechanisms, called endotypes. Thus, asthma therapy is gradually moving to a personalized medicine approach, tailored to individual's asthma endotypes identified through biomarkers. Here, we review the clinical efficacy of antibody-related therapeutics undergoing clinical trials, or those already approved, for the treatment of severe type 2 asthma. Biologics targeting type 2 cytokines have shown consistent efficacy, especially in patients with evidence of type 2 inflammation, suggesting that the future of asthma biologics is promising.     

Cutting edge: the absence of C3 demonstrates a role for complement in Th2 effector functions in a murine model of pulmonary allergy

Asthma is a chronic disease of the lung resulting from airway obstruction. Although the initiating causes are not entirely clear, the airway inflammation in asthma is associated with Th2 lymphocytes and their cytokines, particularly IL-4, which play a prominent role in this disease by regulating airway hyperresponsiveness, eosinophil activation, and IgE synthesis. Historically, complement was not thought to contribute to the pathogenesis of asthma. However, using C3-deficient mice in an allergen-induced model of pulmonary allergy, we demonstrate that complement may impact key features of this disease. When challenged with allergen, mice deficient in C3 exhibit diminished airway hyperresponsiveness and lung eosinophilia. Furthermore, these mice also have dramatically reduced numbers of IL-4-producing cells and attenuated Ag-specific IgE and IgG1 responses. Collectively, these results demonstrate that C3-deficient mice have significantly altered allergic lung responses and indicate a role for the complement system in promoting Th2 effector functions in asthma.     

Epithelium-fibroblast interactions in response to airway inflammation

Dramatic changes to the architecture of the airway walls have been commonly described in the airways of patients with asthma, cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Much research has focused on how airway inflammation drives these structural changes, particularly in terms of the mechanisms/mediators that are involved, and a number of parallels are observed between the disease phenotypes. For example, the increased deposition of extracellular matrix (ECM) at focal sites in the airway wall is seen in asthma and all interstitial lung diseases that involve fibrosis. In addition, increased expression of a number of well characterized cytokines and growth factors, such as TGF-beta and epidermal growth factor (EGF) have been demonstrated in these diseases. However, the role of the lesser-known cytokines, including the leukaemia inhibitory factor (LIF) and other members of the IL-6 family of cytokines in the pathogenesis of airway remodelling and fibrosis is largely unknown. However, the use of genetic manipulation in vivo and more specific inhibitors/antibodies in vitro has now provided increasing evidence to support the hypothesis that a complex interaction exists between these cytokines, ECM and integrins in regulating the function of both epithelial cells and fibroblasts.     

5A, an apolipoprotein A-I mimetic peptide, attenuates the induction of house dust mite-induced asthma

New treatment approaches are needed for patients with asthma. Apolipoprotein A-I (apoA-I), the major structural protein of high-density lipoproteins, mediates reverse cholesterol transport and has atheroprotective and anti-inflammatory effects. In this study, we hypothesized that an apoA-I mimetic peptide might be effective at inhibiting asthmatic airway inflammation. A 5A peptide, which is a synthetic, bihelical apoA-I mimetic, was administered to wild-type A/J mice via osmotic mini-pump prior to the induction of house dust mite (HDM)-induced asthma. HDM-challenged mice that received the 5A apoA-I mimetic peptide had significant reductions in the number of bronchoalveolar lavage fluid eosinophils, lymphocytes, and neutrophils, as well as in histopathological evidence of airway inflammation. The reduction in airway inflammation was mediated by a reduction in the expression of Th2- and Th17-type cytokines, as well as in chemokines that promote T cell and eosinophil chemotaxis, including CCL7, CCL17, CCL11, and CCL24. Furthermore, the 5A apoA-I mimetic peptide inhibited the alternative activation of pulmonary macrophages in the lungs of HDM-challenged mice. It also abrogated the development of airway hyperresponsiveness and reduced several key features of airway remodeling, including goblet cell hyperplasia and the expression of collagen genes (Col1a1 and Col3a1). Our results demonstrate that the 5A apoA-I mimetic peptide attenuates the development of airway inflammation and airway hyperresponsiveness in an experimental murine model of HDM-induced asthma. These data support the conclusion that strategies using apoA-I mimetic peptides, such as 5A, might be developed further as a possible new treatment approach for asthma.     

The role of cytokines in the pathogenesis of cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is an inflammatory disease with a broad range of cutaneous manifestations that may be accompanied by systemic symptoms. The pathogenesis of CLE is complex, multifactorial and incompletely defined. Below we review the current understanding of the cytokines involved in these processes. Ultraviolet (UV) light plays a central role in the pathogenesis of CLE, triggering keratinocyte apoptosis, transport of nucleoprotein autoantigens to the keratinocyte cell surface and the release of inflammatory cytokines (including interferons (IFNs), tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, IL-8, IL-10 and IL-17). Increased IFN, particularly type I IFN, is central to the development of CLE lesions. In CLE, type I IFN is produced in response to nuclear antigens, immune complexes and UV light. Type I IFN increases leukocyte recruitment to the skin via inflammatory cytokines, chemokines, and adhesion molecules, thereby inducing a cycle of cutaneous inflammation. Increased TNFα in CLE may also cause inflammation. However, decreasing TNFα with an anti-TNFα agent can induce CLE-like lesions. TNFα regulates B cells, increases the production of inflammatory molecules and inhibits the production of IFN-α. An increase in the inflammatory cytokines IL-1, IL-6, IL-10, IL-17 and IL-18 and a decrease in the anti-inflammatory cytokine IL-12 also act to amplify inflammation in CLE. Specific gene mutations may increase the levels of these inflammatory cytokines in some CLE patients. New drugs targeting various aspects of these cytokine pathways are being developed to treat CLE and systemic lupus erythematosus (SLE).     

Allergic Inflammation—Innately Homeostatic

Allergic inflammation is associated closely with parasite infection but also asthma and other common allergic diseases. Despite the engagement of similar immunologic pathways, parasitized individuals often show no outward manifestations of allergic disease. In this perspective, we present the thesis that allergic inflammatory responses play a primary role in regulating circadian and environmental inputs involved with tissue homeostasis and metabolic needs. Parasites feed into these pathways and thus engage allergic inflammation to sustain aspects of the parasitic life cycle. In response to parasite infection, an adaptive and regulated immune response is layered on the host effector response, but in the setting of allergy, the effector response remains unregulated, thus leading to the cardinal features of disease. Further understanding of the homeostatic pressures driving allergic inflammation holds promise to further our understanding of human health and the treatment of these common afflictions.Buoyed by the successes of prophylactic immunization against toxins at the turn of the 20th century, Portier and Richet began studies with hypnotoxin from the cnidarian, Physalia physalis, commonly known as the Portuguese man o’ war, and a related toxin from the sea anemones, Actinia equina and Anemonia sulcata. These investigations led to the paradoxical discovery of immediate hypersensitivity reactions and even death among some immunized animals by a process termed “anaphylaxis” (Richet 1913). Recognized by a Nobel Prize, these seminal findings underpinned the modern field of allergy and led to the eventual identification of the transferable nature of the activating agent in serum, first noted by Richet, as immunoglobulin E (IgE) (Ishizaka et al. 1966). The rapid advances in molecular biology, genetics, and genomics from 1970 to 2000 elucidated the central role for cytokines, particularly the duplicated genes for interleukin (IL)-4, IL-13, IL-5, and IL-9, in mediating the effector functions of allergic immunity. Although initial studies fueled by the discoveries of helper T-cell subsets focused on T cells, designated Th2 cells, as sources of these cytokines, recent findings have increasingly highlighted the role of innate cells in allergic immunity. These discoveries have raised hopes that insights regarding the initiation and/or maintenance of tissue pathology mediated by interactions between innate and adaptive cells might translate to new therapeutic modalities for diseases underpinned by type 2 immunity.     

Stimulation of airway mucin gene expression by interleukin (IL)-17 through IL-6 paracrine/autocrine loop

Mucus hypersecretion and persistent airway inflammation are common features of various airway diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. One key question is: does the associated airway inflammation in these diseases affect mucus production? If so, what is the underlying mechanism? It appears that increased mucus secretion results from increased mucin gene expression and is also frequently accompanied by an increased number of mucous cells (goblet cell hyperplasia/metaplasia) in the airway epithelium. Many studies on mucin gene expression have been directed toward Th2 cytokines such as interleukin (IL)-4, IL-9, and IL-13 because of their known pathophysiological role in allergic airway diseases such as asthma. However, the effect of these cytokines has not been definitely linked to their direct interaction with airway epithelial cells. In our study, we treated highly differentiated cultures of primary human tracheobronchial epithelial (TBE) cells with a panel of cytokines (interleukin-1alpha, 1beta, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, and tumor necrosis factor alpha). We found that IL-6 and IL-17 could stimulate the mucin genes, MUC5B and MUC5AC. The Th2 cytokines IL-4, IL-9, and IL-13 did not stimulate MUC5AC or MUC5B in our experiments. A similar stimulation of MUC5B/Muc5b expression by IL-6 and IL-17 was demonstrated in primary monkey and mouse TBE cells. Further investigation of MUC5B expression demonstrated that IL-17's effect is at least partly mediated through IL-6 by a JAK2-dependent autocrine/paracrine loop. Finally, evidence is presented to show that both IL-6 and IL-17 mediate MUC5B expression through the ERK signaling pathway.     

Immune regulation of myeloma cells

MM is a B-cell neoplasm that is accompanied by a variety of qualitative and quantitative alterations in immunoregulatory cells. Interactions between myeloma cells and immunoregulatory cells may relate both to disease progression and to some of the complications of MM, including hypogammaglobulinemia. Of particular interest is the relationship between stable-phase or plateau-phase myeloma and increased numbers of T-suppressor cells. In addition, the more recent discovery of production of certain interleukins and the presence of interleukin receptors on the plasma membranes of myeloma cells suggest that these cytokines may be involved in oncogenesis in MM. Because these cytokines may also be produced by immunoregulatory cells, further work needs to be done to determine the relative contribution of cytokines to the growth and regulation of myeloma cells. Finally, it is also possible that certain interleukins may be efficacious in the treatment of patients with MM.     

Budesonide and formoterol reduce early innate anti-viral immune responses in vitro

Asthma is a chronic inflammatory airways disease in which respiratory viral infections frequently trigger exacerbations. Current treatment of asthma with combinations of inhaled corticosteroids and long acting beta2 agonists improves asthma control and reduces exacerbations but what impact this might have on innate anti-viral immunity is unclear. We investigated the in vitro effects of asthma drugs on innate anti-viral immunity. Peripheral blood mononuclear cells (PBMC) from healthy and asthmatic donors were cultured for 24 hours with the Toll-like receptor 7 agonist, imiquimod, or rhinovirus 16 (RV16) in the presence of budesonide and/or formoterol. Production of proinflammatory cytokines and expression of anti-viral intracellular signalling molecules were measured by ELISA and RT-PCR respectively. In PBMC from healthy donors, budesonide alone inhibited IP-10 and IL-6 production induced by imiquimod in a concentration-dependent manner and the degree of inhibition was amplified when budesonide and formoterol were used in combination. Formoterol alone had little effect on these parameters, except at high concentrations (10⁻⁶ M) when IL-6 production increased. In RV16 stimulated PBMC, the combination of budesonide and formoterol inhibited IFNα and IP-10 production in asthmatic as well as healthy donors. Combination of budesonide and formoterol also inhibited RV16-stimulated expression of the type I IFN induced genes myxovirus protein A and 2′, 5′ oligoadenylate synthetise. Notably, RV16 stimulated lower levels of type Myxovirus A and oligoadenylate synthase in PBMC of asthmatics than control donors. These in vitro studies demonstrate that combinations of drugs commonly used in asthma therapy inhibit both early pro-inflammatory cytokines and key aspects of the type I IFN pathway. These findings suggest that budesonide and formoterol curtail excessive inflammation induced by rhinovirus infections in patients with asthma, but whether this inhibits viral clearance in vivo remains to be determined.     

The role of interferon-gamma on immune and allergic responses

Allergic diseases have been closely related to Th2 immune responses, which are characterized by high levels of interleukin (IL) IL-4, IL-5, IL-9 and IL-13. These cytokines orchestrate the recruitment and activation of different effector cells, such as eosinophils and mast cells. These cells along with Th2 cytokines are key players on the development of chronic allergic inflammatory disorders, usually characterized by airway hyperresponsiveness, reversible airway obstruction, and airway inflammation. Accumulating evidences have shown that altering cytokine-producing profile of Th2 cells by inducing Th1 responses may be protective against Th2-related diseases such as asthma and allergy. Interferon-gamma (IFN-gamma), the principal Th1 effector cytokine, has shown to be crucial for the resolution of allergic-related immunopathologies. In fact, reduced production of this cytokine has been correlated with severe asthma. In this review, we will discuss the role of IFN-gamma during the generation of immune responses and its influence on allergic inflammation models, emphasizing its biologic properties during the different aspects of allergic responses.     

HIV-1, macrophages, glial cells, and cytokines in AIDS nervous system disease

Hallmarks of central nervous system (CNS) disease in AIDS patients are headaches, fever, subtle cognitive changes, abnormal reflexes, and ataxia. Dementia and severe sensory and motor dysfunction characterize more severe disease. Autoimmune-like peripheral neuropathies, cerebrovascular disease, and brain tumors are also observed. Histological changes include inflammation, astrocytosis, microglial nodule formation, and diffuse de- or dysmyelination. Focal demyelination can also be seen. It is clear that AIDS-associated neurological diseases are correlated with greater levels of HIV-1 antigen or genome in tissues. In AIDS dementia, macrophages and microglial cells of the CNS are the predominant cell types infected and producing HIV-1. However, manifestations of the disease make it unlikely that direct infection by HIV-1 is responsible. It seems more likely that the effects are mediated through secretion of viral proteins or viral induction of cytokines that bind to glial cells and neurons. HIV-1 induction of such cytokines as interleukin 1 (IL 1) and tumor necrosis factor-alpha (TNF alpha) may lead to an autocrine feedback loop involving further productive virus replication and induction of other cytokines such as interleukin 6 (IL 6) and granulocyte-macrophage colony-stimulating factor (GMCSF). Interleukin 1 and TNF alpha in combination with IL 6 and GMCSF could account for many clinical and histopathological findings in AIDS nervous system diseases. As HIV-1 infected patients produce elevated levels of IL 1, TNF alpha, and IL 6, it will be important to make a formal connection between the presence of these factors in the CNS, which are all products of activated macrophages, astroglia, and microglia, their in vivo induction directly by virus or indirectly by virus-induced intermediates, and the clinical and pathological conditions seen in the nervous system in this disease.