Cysteinyl-leukotrienes induce vascular endothelial growth factor production in human monocytes and bronchial smooth muscle cells

The role of human mast cells in allergy and asthma

Mast cells are tissue-inhabiting cells that play an important role in inflammatory diseases of the airway tract. Mast cells arise in the bone marrow as progenitor cells and complete their differentiation in tissues exposed to the external environment, such as the skin and respiratory tract, and are among the first to respond to bacterial and parasitic infections. Mast cells express a variety of receptors that enable them to respond to a wide range of stimulants, including the high-affinity FcεRI receptor. Upon initial contact with an antigen, mast cells are sensitized with IgE to recognize the allergen upon further contact. FcεRI-activated mast cells are known to release histamine and proteases that contribute to asthma symptoms. They release a variety of cytokines and lipid mediators that contribute to immune cell accumulation and tissue remodeling in asthma. Mast cell mediators trigger inflammation and also have a protective effect. This review aims to update the existing knowledge on the mediators released by human FcεRI-activated mast cells, and to unravel their pathological and protective roles in asthma and allergy. In addition, we highlight other diseases that arise from mast cell dysfunction, the therapeutic approaches used to address them, and fill the gaps in our current knowledge. Mast cell mediators not only trigger inflammation but may also have a protective effect. Given the differences between human and animal mast cells, this review focuses on the mediators released by human FcεRI-activated mast cells and the role they play in asthma and allergy.

Leukotriene D4 role in allergic asthma pathogenesis from cellular and therapeutic perspectives

Asthma is a chronic inflammatory and allergic disease that is mainly characterized by reversible airway obstruction and bronchial hyperresponsiveness. The incidence of asthma is increasing with more than 350 million people worldwide are affected. Up to now, there is no therapeutic option for asthma and most of the prescribed drugs aim to ameliorate the symptoms of the disease especially during the acute exacerbations after trigger exposure. Asthma is a heterogonous disease that involves interactions between inflammatory mediators and cellular components within the disease microenvironment including inflammatory and structural cells. Cysteinyl leukotrienes (cys-LTs) are inflammatory lipid mediators that have potent roles in asthma pathogenesis. CysLTs consisting of LTC₄, LTD₄, and LTE₄ are mainly secreted by leukocytes and act through three main G-protein coupled receptors (CysLT₁R, CysLT₂R, and CysLT₃R). LTD₄ is the most potent bronchoconstrictor which gives it the priority to be discussed in detail in this review. LTD₄ binds with high affinity to CysLT₁R and many studies showed that using CysLT₁R antagonists such as montelukast has a beneficial effect for asthmatics especially in corticosteroid refractory cases. Since asthma is a heterogeneous inflammatory disease of many cell types involved in the disease pathogenies and LTD₄ has a special role in inflammation and bronchoconstriction, this review highlights the role of LTD₄ on each cellular component in asthma and the benefits of using CysLT₁R antagonists in ameliorating LTD₄-induced effects.

Montelukast Prevents Early Diabetic Retinopathy in Mice

Chronic inflammation and oxidative stress are critical components in the pathogenic cascade of early diabetic retinopathy, characterized by neuronal and vascular degeneration. We investigated pharmacologic inhibition of the proinflammatory leukotriene cascade for therapeutic benefit in early diabetic retinopathy. Using the streptozotocin-induced diabetes mouse model, we administered montelukast, a leukotriene receptor antagonist, and diabetes-related retinal pathology was assessed. Early biochemical and cellular function measures were evaluated at 3 months' diabetes duration and included vascular permeability, superoxide production, leukotriene generation, leukocyte-induced microvascular endothelial cell death, and retinal function by electroretinography. Histopathology assessments at 9 months' diabetes duration included capillary degeneration and retinal ganglion cell loss. Leukotriene receptor antagonism resulted in a significant reduction of early, diabetes-induced retinal capillary leakage, superoxide generation, leukocyte adherence, and leukotriene generation. After 9 months of diabetes, the retinal microvasculature from untreated diabetic mice demonstrated a nearly threefold increase in capillary degeneration compared with nondiabetic mice. Montelukast inhibited the diabetes-induced capillary and neuronal degeneration, whether administered as a prevention strategy, immediately after induction of diabetes, or as an intervention strategy starting at 4.5 months after confirmation of diabetes. Pharmacologic blockade of the leukotriene pathway holds potential as a novel therapy to prevent or slow the development of diabetic retinopathy.

Tumor-associated macrophages: a short compendium

Macrophages play an important role in tissue development and homeostasis. They serve as a nexus between adaptive and innate immunity, and employ considerable plasticity. In cancer, they play a pivotal role in chronic inflammation and tumor growth either by directly stimulating the proliferation of cancer cells or by producing angiogenic and lymphangiogenic factors. Although numerous immune cells play an important role in the tumor microenvironment, tumor-associated macrophages (TAMs) are by far the most extensively studied. A better understanding of the role of TAMs in mediating chemo- and radiotherapy resistance and suppressing immunosurveillance has led to numerous strategies targeting TAMs as an anticancer therapy either by targeting them directly or by polarizing TAMs toward a tumoricidal phenotype.

Innate effector cells in angiogenesis and lymphangiogenesis

Angiogenesis and lymphangiogenesis are distinct and complex processes requiring a finely tuned balance between stimulatory and inhibitory signals. During adulthood, angiogenesis and lymphangiogenesis are activated at sites of tumor growth, tissue injury and remodeling, and chronic inflammation. Vascular endothelial growth factors (VEGFs), angiopoietin (ANGPTs) and a multitude of additional signaling molecules play distinct roles in the modulation of angiogenesis/lymphangiogenesis. VEGFs and ANGPTs activate specific tyrosine kinase receptor (e.g., VEGFR1, VEGFR-2, VEGFR-3 and TIE2 respectively), expressed on blood endothelial cells (angiogenesis) and lymphatic endothelial cells (lymphangiogenesis). Although tumor cells produce VEGFs and other proangiogenic mediators, tissue resident (e.g., macrophages, mast cells) and circulating immune cells (e.g., basophils, neutrophils, monocytes, eosinophils) are an important source of angiogenic/lymphangiogenic mediators in inflammation and in tumor microenvironment and at site of chronic inflammation. Certain immune cells can also release anti-angiogenic factors. Mast cells, basophils, neutrophils and presumably other immune cells are not only a source of angiogenic/lymphangiogenic molecules, but also their target. Cells of the immune system need consideration as major players and possible targets for therapeutic manipulation of angiogenesis/lymphangiogenesis in chronic inflammatory disorders and tumors.

GM-CSF- and M-CSF-primed macrophages present similar resolving but distinct inflammatory lipid mediator signatures

M1 and M2 activated macrophages (Mϕs) have different roles in inflammation. Because pathogens may first encounter resting cells, we investigated lipid mediator profiles prior to full activation. Human monocytes were differentiated with granulocyte Mϕ colony-stimulating factor (GM-CSF) or Mϕ colony-stimulating factor (M-CSF), which are known to prime toward M1 or M2 phenotypes, respectively. Lipid mediators released during resting conditions and produced in response to bacterial stimuli (LPS/N-formylmethionyl-leucyl-phenylalanine or peptidoglycan) were quantified by liquid chromatography-mass spectrometry. In resting conditions, both Mϕ phenotypes released primarily proresolving lipid mediators (prostaglandin E₂ metabolite, lipoxin A₄, and 18-hydroxyeicosapentaenoic acid). A striking shift toward proinflammatory eicosanoids was observed when the same cells were exposed (30 min) to bacterial stimuli: M-CSF Mϕs produced considerably more 5-lipoxygenase products, particularly leukotriene C₄, potentially linked to M2 functions in asthma. Prostaglandins were formed by both Mϕ types. In the M-CSF cells, there was also an enhanced release of arachidonic acid and activation of cytosolic phospholipase A₂ However, GM-CSF cells expressed higher levels of 5-lipoxygenase and 5-lipoxygenase-activating protein, and in ionophore incubations these cells also produced the highest levels of 5-hydroxyeicosatetraenoic acid. In summary, GM-CSF and M-CSF Mϕs displayed similar proresolving lipid mediator formation in resting conditions but shifted toward different proinflammatory eicosanoids upon bacterial stimuli. This demonstrates that preference for specific eicosanoid pathways is primed by CSFs before full M1/M2 activation.-Lukic, A., Larssen, P., Fauland, A., Samuelsson, B., Wheelock, C. E., Gabrielsson, S., Radmark, O. GM-CSF- and M-CSF-primed macrophages present similar resolving but distinct inflammatory lipid mediator signatures.

Alleviating Promotion of Inflammation and Cancer Induced by Nonsteroidal Anti-Inflammatory Drugs

Clinical Relevance

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) including aspirin are of intensive use nowadays. These drugs exert their activity via the metabolism of arachidonic acid (AA) by cyclooxygenase inhibition. Though beneficial for health in some instances, both unspecific and specific cyclooxygenase inhibitor activity interfere with AA metabolism producing also proinflammatory lipids that may promote cancer.

Materials and Methods

This review is based on available literature on clinical uses, biochemical investigations, molecular medicine, pharmacology, toxicity, and epidemiology-clinical studies on NSAIDs and other drugs that may be used accordingly, which was collected from electronic (SciFinder, Medline, Science Direct, and ACS among others) and library searches of books and journals.

Results

Relevant literature supports the notion that NDSAID use may also promote proinflammatory biochemical events that are also related to precancerous predisposition. Several agents are proposed that may be employed in immediate future to supplement and optimize treatment with NSAIDs. In this way serious side effects arising from promotion of inflammation and cancer, especially in chronic NSAID users and high risk groups of patients, could be avoided.

[Effect of montelukast sodium intervention on airway remodeling and percentage of Th17 cells/CD4+CD25+ regulatory T cells in asthmatic mice]

OBJECTIVE

To study the dynamic changes in the percentage of Th17 cells/CD4⁺CD25⁺ regulatory T cells after intervention with montelukast sodium, a leukotriene receptor antagonist, in asthmatic mice and the association between them.

METHODS

Balb/c mice were randomly divided into blank group, asthma group, and montelukast sodium group. The asthmatic mouse model of airway remodeling was established by sensitization with intraperitoneal injection of chicken ovalbumin (OVA) and aluminum hydroxide suspension and aerosol inhalation of OVA. The mice in the blank group were given normal saline, and those in the montelukast sodium group were given montelukast sodium by gavage before aerosol inhalation. Eight mice were randomly sacrificed within 24 hours after 2, 4, and 8 weeks of aerosol inhalation. The pathological sections of lung tissue were used to observe the degree of airway remodeling. Flow cytometry was used to measure the percentages of Th17 cells and CD4⁺CD25⁺ regulatory T cells in CD4⁺ T cells.

RESULTS

The asthma group and the montelukast sodium group had significantly higher bronchial wall thickness and smooth muscle thickness at all time points compared with the blank group (P<0.05). At 8 weeks of intervention, the montelukast sodium group had significantly greater improvements in the above changes compared with the asthma group (P<0.05). Compared with the blank group, the asthma group and the montelukast sodium group had significant increases in Th17 cells (positively correlated with airway remodeling) and significant reductions in CD4⁺CD25⁺ regulatory T cells (negatively correlated to airway remodeling) at all time points (P<0.05). At 8 weeks of intervention, the montelukast sodium group had a significant reduction in the number of Th17 cells and a significant increase in the number of CD4⁺CD25⁺ regulatory T cells compared with the asthma group (P<0.05).

CONCLUSIONS

Montelukast sodium intervention can alleviate airway remodeling and achieve better improvements over the time of intervention. The possible mechanism may be related to the improvement of immunologic derangement of CD4⁺CD25⁺ regulatory T cells and inhibition of airway inflammation.

Evaluation of Cysteinyl Leukotriene Signaling as a Therapeutic Target for Colorectal Cancer

Colorectal cancer is the third most common cancer worldwide and is associated with significant morbidity and mortality. Current pharmacotherapy options include cytotoxic chemotherapy, anti-VEGF, and anti-EGFR targeting drugs, but these are limited by toxic side effects, limited responses and ultimately resistance. Cysteinyl leukotriene (CysLT) signaling regulates intestinal homeostasis with mounting evidence suggesting that CysLT signaling also plays a role in the pathogenesis of colorectal cancer. Therefore, CysLT signaling represents a novel target for this malignancy. This review evaluates reported links between CysLT signaling and established hallmarks of cancer in addition to its pharmacological potential as a new therapeutic target.

Leukotriene B4 Receptor 2 Is Critical for the Synthesis of Vascular Endothelial Growth Factor in Allergen-Stimulated Mast Cells

Mast cells are among the principal effector cells in the pathogenesis of allergic asthma. In allergic reactions, allergen (Ag)-induced cross-linking of IgE bound to FcεRI on mast cells results in the production of vascular endothelial growth factor (VEGF), which is essential for the initiation and development of the allergic response. Despite the central role of VEGF in allergic asthma, the signaling events responsible for the production of VEGF remain unclear, particularly in Ag-stimulated mast cells. In the present study, we observed that blocking leukotriene B4 receptor 2 (BLT2) completely abrogated the production of VEGF in Ag-stimulated bone marrow-derived mast cells (BMMCs). The synthesis of BLT2 ligands (leukotriene B4 and 12(S)-hydroxyeicosatetraenoic acid) was also required for VEGF production, suggesting a mediating role of an autocrine BLT2 ligands-BLT2 axis in the production of VEGF in mast cells. The NADPH oxidase 1-reactive oxygen species-NF-κB cascade is downstream of BLT2 during Ag signaling to VEGF synthesis in mast cells. Furthermore, the level of VEGF synthesis in genetically mast cell-deficient Kit(W/Wv) mice was significantly lower than that in wild-type mice in the OVA-induced asthma model, suggesting that mast cells play a critical role in the synthesis of VEGF in OVA-induced allergic asthma. Importantly, VEGF production was restored to the levels observed in wild-type mice after adoptive transfer of normal BMMCs into Kit(W/Wv) mice but was not restored in BLT2(-/-) BMMC-reconstituted Kit(W/Wv) mice in the OVA-induced asthma model. Taken together, our results suggest that BLT2 expression in mast cells is essential for the production of VEGF in OVA-induced allergic asthma.

CysLT1 Receptor Is Protective against Oxidative Stress in a Model of Irritant-Induced Asthma

The bronchoconstrictive and proinflammatory properties of cysteinyl leukotrienes (cysLTs) in allergic asthma mediate their effects predominantly through the cysLT1 receptor (cysLT1R). However, the role of cysLTs and cysLT1R in innate immune-triggered asthma is largely unexplored. We explored the synthesis of cysLTs and cysLT1R as determinants of airway responses in an oxidative stress-induced model of irritant asthma. Wild-type (WT) mice exposed to 100 ppm Cl2 for 5 min had airway neutrophilia, increased cysLT production, and pulmonary expression of cysLT-related biosynthetic genes. CysLT1R-deficient (CysLTr1(-/-)) mice that were exposed to Cl2 demonstrated airway hyperresponsiveness to inhaled methacholine significantly greater than in WT BALB/c mice. Compared to WT mice, airway neutrophilia and keratinocyte chemoattractant production levels were higher in CysLTr1(-/-) mice and airway hyperresponsiveness was ameliorated using a granulocyte depletion Ab. CysLTr1(-/-) mice also demonstrated prolonged bronchial epithelial cell apoptosis following Cl2 WT mice showed increased antioxidant and NF erythroid 2-related factor 2 (Nrf2) gene expression, Nrf2 nuclear translocation in bronchial epithelial cells, and increased reduced glutathione/oxidized glutathione following Cl2 exposure whereas CysLTr1(-/-) mice did not. Furthermore, CysLTr1(-/-) mice demonstrated increased pulmonary E-cadherin expression and soluble E-cadherin shedding compared with WT mice. Loss of a functional cysLT1R results in aberrant antioxidant response and increased susceptibility to oxidative injury, apparently via a cysLT1R-dependent impairment of Nrf2 function.

Level of Fatty Acid Binding Protein 5 (FABP5) Is Increased in Sputum of Allergic Asthmatics and Links to Airway Remodeling and Inflammation

BACKGROUND

The inflammatory processes in the upper and lower airways in allergic rhinitis and asthma are similar. Induced sputum and nasal lavage fluid provide a non-invasive way to examine proteins involved in airway inflammation in these conditions.

OBJECTIVES

We conducted proteomic analyses of sputum and nasal lavage fluid samples to reveal differences in protein abundances and compositions between the asthma and rhinitis patients and to investigate potential underlying mechanisms.

METHODS

Induced sputum and nasal lavage fluid samples were collected from 172 subjects with 1) allergic rhinitis, 2) asthma combined with allergic rhinitis, 3) nonallergic rhinitis and 4) healthy controls. Proteome changes in 21 sputum samples were analysed with two-dimensional difference gel electrophoresis (2D-DIGE), and the found differentially regulated proteins identified with mass spectrometry. Immunological validation of identified proteins in the sputum and nasal lavage fluid samples was performed with Western blot and ELISA.

RESULTS

Altogether 31 different proteins were identified in the sputum proteome analysis, most of these were found also in the nasal lavage fluid. Fatty acid binding protein 5 (FABP5) was up-regulated in the sputum of asthmatics. Immunological validation in the whole study population confirmed the higher abundance levels of FABP5 in asthmatic subjects in both the sputum and nasal lavage fluid samples. In addition, the vascular endothelial growth factor (VEGF) level was increased in the nasal lavage fluid of asthmatics and there were positive correlations between FABP5 and VEGF levels (r=0.660, p<0.001) and concentrations of FABP5 and cysteinyl leukotriene (CysLT) (r=0.535, p<0.001) in the nasal lavage fluid.

CONCLUSIONS

FABP5 may contribute to the airway remodeling and inflammation in asthma by fine-tuning the levels of CysLTs, which induce VEGF production.

Enhanced cysteinyl-leukotriene type 1 receptor expression in T cells from house dust mite-allergic individuals following stimulation with Der p

In order to determine the potential for allergen to modulate T cell expression of the CysLT₁ receptor and responsiveness to leukotrienes, peripheral blood mononuclear cells from house dust mite-allergic or nonallergic individuals were incubated with D. pteronyssinus allergen (Der p). Baseline CysLT₁ expression was similar in both groups of donors, but Der p significantly enhanced CysLT₁ expression in CD4⁺ and CD8⁺ T cells of only allergic individuals and induced enhanced responsiveness of CD4⁺ T cells to LTD₄ in terms of calcium mobilisation. This effect was prevented by the CysLT₁ antagonist MK571. Der p also induced IL-4 and IL-10 production, and neutralizing antibody to IL-4 prevented both the enhanced CysLT₁ expression and the enhanced responsiveness of T cells to LTD₄ induced by Der p. In allergic individuals, Der p also induced T cell proliferation and a Th2-biased phenotype. Our data suggest that, in allergen-sensitized individuals, exposure to allergen can enhance T cell expression of CysLT₁ receptors through a mechanism involving IL-4 production. This, in turn, would induce CD4⁺ T cell responsiveness to cysteinyl-leukotrienes and Th2 cell activation.

Update on leukotriene, lipoxin and oxoeicosanoid receptors: IUPHAR Review 7

The endogenous ligands for the LT, lipoxin (LX) and oxoeicosanoid receptors are bioactive products produced by the action of the lipoxygenase family of enzymes. The LT receptors BLT1 and BLT2 , are activated by LTB4 and the CysLT1 and CysLT2 receptors are activated by the cysteinyl-LTs, whereas oxoeicosanoids exert their action through the OXE receptor. In contrast to these pro-inflammatory mediators, LXA4 transduces responses associated with the resolution of inflammation through the receptor FPR2/ALX (ALX/FPR2). The aim of the present review is to give a state of the field on these receptors, with focus on recent important findings. For example, BLT1 receptor signalling in cancer and the dual role of the BLT2 receptor in pro- and anti-inflammatory actions have added more complexity to lipid mediator signalling. Furthermore, a cross-talk between the CysLT and P2Y receptor systems has been described, and also the presence of novel receptors for cysteinyl-LTs, such as GPR17 and GPR99. Finally, lipoxygenase metabolites derived from ω-3 essential polyunsaturated acids, the resolvins, activate the receptors GPR32 and ChemR23. In conclusion, the receptors for the lipoxygenase products make up a sophisticated and tightly controlled system of endogenous pro- and anti-inflammatory signalling in physiology and pathology.

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

Vascular endothelial growth factor and cysteinyl leukotrienes in sputum supernatant of patients with asthma

BACKGROUND

Vascular endothelial growth factor (VEGF) is considered to be the most important angiogenic factor in asthma. Cysteinyl leukotrienes (Cyst-LTs) have been implicated in vascular permeability in asthma. Cyst-LTs receptor antagonists modulate vascular permeability by reducing VEGF expression.

OBJECTIVE

We aimed to determine the levels of VEGF and Cyst-LTs in sputum supernatants of patients with asthma and to investigate possible associations within them and with airway vascular permeability (AVP) index. Possible confounding factors were also assessed.

METHODS

One hundred twenty one patients with asthma (38 with severe refractory asthma, 41 smokers) and 30 healthy subjects (15 smokers) were studied. All subjects underwent lung function tests, and sputum induction for cell count identification and VEGF, Cyst-LTs, measurement in supernatants. AVP index was also assessed.

RESULTS

Both VEGF & Cyst-LTs (pg/ml) levels were significantly elevated in patients with asthma compared to normal subjects (median, interquartile ranges 845 [487-1034] vs. 432 (327-654) and 209 [171-296] vs. 92 [75-114] respectively, p < 0.001 for both). Multivariate regression analysis in the whole group showed a significant association of Cyst-LTs levels in sputum supernatants with VEGF levels in sputum supernatants and AVP index. A similar positive association was observed between VEGF levels in sputum supernatants and AVP index. The presence of Severe asthma was a significant covariate for both associations.

CONCLUSION

Our results indicate that Cyst-LTs may modulate vascular permeability by up-regulating VEGF expression. The above effect seems to be affected by asthma severity.

Developments in the field of allergy in 2011 through the eyes of Clinical and Experimental Allergy

As in previous years, we felt it would be of value to our readership to summarize the new information provided by the authors who have published in Clinical and Experimental Allergy in 2011 and set this in the context of recent advances in our understanding of the pathogenesis and management of allergic disease in all its many manifestations. In 2011, about 210 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, guidelines, letters, book reviews and of course at the heart of the journal, papers containing original data. As before, this review is divided into sections based on the way the journal is structured, although this year we have grouped together all the papers dealing with mechanisms of allergic disease, whether they involve patients (clinical mechanisms), pure in vitro studies (basic mechanisms) or animal models (experimental models), as we felt this was a more coherent way to deal with the subject. In the field of asthma and rhinitis, the relationship between airway inflammation and airway dysfunction was of perennial interest to investigators, as were phenotypes and biomarkers. Aspirin hypersensitivity appeared in studies in several papers and there was new interest in asthma in the elderly. The mechanisms involved in allergic disease describe advances in our understanding of T cell responses, the relationship between inflammation and disease, mast cell and basophil activation, steroid resistance and novel therapies. In the section dealing with epidemiology, studies seeking to identify risk factors for allergic disease including vitamin D are prominent, as once again are studies investigating gene-environment interactions. The clinical allergy section focuses on drug allergy, food allergy and immunotherapy. The area of oral immunotherapy for food allergy is well covered and we were grateful to Stephen Durham for guest editing an outstanding special issue on immunotherapy in the centenary year of Leonard Noon's pioneering work. Lastly, in the field of allergens, the interest in component-resolved diagnosis continues to grow and there are also articles describing important novel cultivars and the effect of food processing on the allergenic properties of foods. Another terrific year, full of important and high-quality work,which the journal has been proud to bring to the allergy community.

Vascular endothelial growth factor as a key inducer of angiogenesis in the asthmatic airways

Asthma is a chronic inflammatory disease of the airways characterized by structural airway changes, which are known as airway remodeling, including smooth muscle hypertrophy, goblet cell hyperplasia, subepithelial fibrosis, and angiogenesis. Vascular remodeling in asthmatic lungs results from increased angiogenesis, which is mainly mediated by vascular endothelial growth factor (VEGF). VEGF is a key regulator of blood vessel growth in the airways of asthma patients by promoting proliferation and differentiation of endothelial cells and inducing vascular leakage and permeability. In addition, VEGF induces allergic inflammation, enhances allergic sensitization, and has a role in Th2 type inflammatory responses. Specific inhibitors of VEGF and blockers of its receptors might be useful to control chronic airway inflammation and vascular remodeling, and might be a new therapeutic approach for chronic inflammatory airway disease like asthma.

Structure-based drug design using GPCR homology modeling: toward the discovery of novel selective CysLT2 antagonists

3D structure of CysLT2 receptor was constructed by using homology modeling and molecular simulations. The binding pocket of CysLT2 receptor and the proposition of the interaction mode between CysLT2 and HAMI3379 were identified. A series of dicarboxylated chalcones was then virtually evaluated through molecular docking studies. A total of six compounds 13a-f with preferable scores was further synthesized and tested for CysLT2 antagonistic activities by determination of the cytosolic free Ca(2+) levels in HEK293 cells. Compounds 13e and 13f exhibited potent and selective CysLT2 antagonistic activities with IC50 values being 7.5 and 0.25 μM, respectively.

Asthma treatment outcome in children is associated with vascular endothelial growth factor A (VEGFA) polymorphisms

BACKGROUND

Asthma is a common chronic disease characterized by airway inflammation and structural remodeling. Vascular endothelial growth factor (VEGF), a major regulator of angiogenesis, is elevated in asthma patients. VEGF contributes to airway responsiveness and remodeling. It has been shown that treatment of asthma patients decreases VEGF levels, and inhibition of VEGF diminishes asthma symptoms in mice. Therefore, polymorphisms in the vascular endothelial growth factor A (VEGFA) gene might be associated with asthma treatment response.

METHODS

This study enrolled 131 children with asthma treated with different therapies - specifically, the inhaled corticosteroid (ICS) fluticasone propionate or the leukotriene receptor antagonist (LTRA) montelukast. We performed an association analysis between improvement of lung function - assessed by measurement of the percentage of the predicted forced expiratory volume in 1 second (%predicted FEV(1)), the ratio between the FEV(1) and the forced vital capacity (FEV(1)/FVC) after 6 and 12 months of treatment, and asthma control after 12 months of treatment - and two polymorphisms, rs2146323 and rs833058, in the VEGFA gene.

RESULTS

Polymorphism rs2146323 A>C in VEGFA was associated with response to ICS therapy. Asthma patients with the AA genotype had a greater improvement in the %predicted FEV(1) than those with the AC or CC genotype (p = 0.018). Conversely, the AA genotype in rs2146323 was associated with uncontrolled asthma in patients regularly receiving LTRA therapy (p = 0.020) and a worse FEV(1)/FVC ratio in patients who episodically used LTRA therapy (p = 0.044). Furthermore, polymorphism rs833058 C>T was associated with treatment response to episodically used LTRA therapy. A subgroup of patients with the TT genotype had an improvement in the %predicted FEV(1), compared with no improvement in patients with the CT or CC genotype (p = 0.029).

CONCLUSIONS

Our results showed that treatment response to commonly used asthma therapies (ICS or LTRA) is associated with polymorphisms rs2146323 and rs833058 in VEGFA. With additional replication of this preliminary study, our findings could contribute to the development of individualized asthma therapy.

Circulating and exhaled vascular endothelial growth factor in asthmatic pregnancy

CONTEXT

Vascular endothelial growth factor (VEGF) plays a role in asthma and pathological pregnancies.

OBJECTIVE

This is the first study assessing plasma and exhaled breath condensate VEGF levels in asthmatic pregnancy.

MATERIAL AND METHODS

Thirty-one asthmatic pregnant, 29 asthmatic nonpregnant, 28 healthy pregnant and 22 healthy nonpregnant women were enrolled. Plasma was collected in all subjects, EBC in 57 volunteers for VEGF measurements.

RESULTS

Plasma VEGF decreased in both pregnant groups (p < 0.01), without any differences between the asthmatic and the respective nonasthmatic groups (p > 0.05). VEGF was undetectable in EBC.

CONCLUSION

Concomitant asthma does not affect plasma VEGF during pregnancy.

Modulation of angiogenesis by dietary phytoconstituents in the prevention and intervention of breast cancer

Breast cancer is the leading cause of cancer-related deaths for women in the United States and the rest of the world. About 8% of women develop breast cancer during the course of their lives. Dietary habits are closely associated with both the risk and progression of breast cancer. Dietary agents have accumulated increasing importance with regards to the prevention and treatment of breast cancer. One such manner by which these compounds can target breast cancer development and progression is through interference with the angiogenic pathways. Angiogenesis is an intricate process that involves the development of new capillaries from previously existing blood vessels. Disruption of this pathway, therefore, provides a novel and effective avenue for therapeutic intervention of breast cancer. Various phytochemicals found in the diet kill breast cancer cells in vitro and prevent as well as suppress breast cancer progression in various preclinical animal models. This review examines the value of dietary phytoconstituents in the prevention and treatment of breast cancer through modulation of the intricate and complex process of angiogenesis. In addition, the potential benefits, challenges, and future directions of research on anti-angiogenic dietary phytochemicals in the prevention and intervention of breast cancer are also addressed.

Leukotriene C(4) prevents the complete maturation of murine dendritic cells and modifies interleukin-12/interleukin-23 balance

Leukotriene C(4) is an important mediator in the development of inflammatory reactions and ischaemia. Previous studies have shown that leukotriene C(4) is able to modulate the function of dendritic cells (DCs) and induce their chemotaxis from skin to lymph node. In this study, we decided to evaluate the modulation exerted by leukotriene C(4) on DCs, depending on their status of activation. We showed for the first time that leukotriene C(4) stimulates endocytosis both in immature and lipopolysaccharide (LPS) -activated DCs. Moreover, it suppressed the interleukin-12p70 (IL-12p70) release, but induces the secretion of IL-23 by DCs activated with LPS and promotes the expansion of T helper type 17 (Th17) lymphocytes. Furthermore, blocking the release of IL-23 reduced the percentages of CD4(+) T cells producing IL-17 in a mixed lymphocyte reaction. Ours results suggest that leukotriene C(4) interferes with the complete maturation of inflammatory DCs in terms of phenotype and antigen uptake, while favouring the release of IL-23, the main cytokine involved in the maintenance of the Th17 profile.