Tumour necrosis factor-alpha blockade suppresses murine allergic airways inflammation

Lactobacillus sakei S1 Improves Colitis Induced by 2,4,6-Trinitrobenzene Sulfonic Acid by the Inhibition of NF-κB Signaling in Mice

Lactobacillus sakei S1 strongly inhibits the expression of interleukin (IL)-6 and IL-1β in lipopolysaccharide-induced peritoneal macrophages by a mechanism for which lactic acid bacteria from kimchi that inhibit tumor necrosis factor-alpha (TNF-κ) were isolated. Therefore, we further evaluated the protective effect of this strain on the colitis mouse model induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS significantly elevated myeloperoxidase (MPO) expression, macroscopic scores, and colon shortening. Oral L. sakei S1 administration resulted in reduction of TNBS-induced loss in body weight, colon shortening, MPO activity, expression of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB). L. sakei S1 inhibited the expression of inflammatory cytokines IL-1β, IL-6 and TNF-κ, induced by TNBS, but enhanced IL-10 expression. L. sakei S1 showed resistance to artificial digestive juices and adherence to intestinal epithelial Caco-2 cells. Thus, L. sakei S1 may inhibit the NF-κB pathway and be used in functional food to treat colitis.

Zinc and iron complexes of oleanolic acid, (OA) attenuate allergic airway inflammation in rats

Oleanolic acid (OA) is a hydroxyl pentacyclic triterpene acid (HTAs) used in various ailments. Inflammatory diseases may be profoundly influenced by iron (Fe) and zinc (Zn) status. We studied the anti-asthmatic effects of two metal complexes (Fe and Zn) of OA in the ovalbumin (OVA)-induced rat model. Delayed type hypersensitivity (DTH) was measured. Total and differential leucocyte count was done in blood as well as bronchoalveolar lavage fluid (BALF). The mRNA expression levels of pro-inflammatory cytokines were measured in lung tissue by reverse transcription polymerase chain reaction. The levels of cyclooxygenase-2 (COX-2), immunoglobulin E (IgE) and 5-lipoxygenase (5-LOX) were estimated by enzyme linked immunosorbent assay. Splenocyte proliferation was performed through BrdU uptake method and nitric oxide levels were measured by colorimetric assay kit. The acute toxicity study was also done for the complexes. The asthmatic group developed allergic airway inflammation shown by increased DTH and inflammatory markers in blood and BALF. OA + Fe and OA + Zn displayed significant decrease in DTH, NO, expression of IL-4, 5, 13, 17, toll-like receptor-2, nuclear factor-kappa B and tumor necrosis factor-α; serum IgE, COX-2, and 5-LOX. The metal complexes also attenuated OVA-stimulated splenocyte proliferation. While no hepatotoxic or nephrotoxic potential was shown by OA + Fe and OA + Zn. Our findings indicate that both OA + Fe and OA + Zn possess significant anti-asthmatic effect which may be ascribed to its immunomodulatory and anti-inflammatory features.

Comparing the effects of fluticasone, anti-IgE and anti-TNF treatments in a chronic asthma model

BACKGROUND

Corticosteroids are used in the treatment of asthma. The aim of this study was to determine the efficacy of anti-IgE and anti-TNF alpha as asthma treatments.

METHODS

A mouse model of chronic asthma was developed. The fluticasone group was exposed to fluticasone and the anti-IgE and anti-TNF groups were administered anti-IgE or anti-TNF. IL-4, and IgE levels were measured, and histological analysis, pathological analysis and miRNA-126, miRNA-133a analyses were applied.

RESULTS

The cell concentration in the BAL fluid decreased in all the treatment groups. The rate of perivascular and peribronchial cell infiltration decreased in the lung in the high-dose anti-IgE and anti-TNF groups. Smooth muscle thickness decreased in the lung tissue in the low-dose anti-IgE and anti-TNF groups. Bronchial wall thickness decreased in the lung tissue in the fluticasone+anti-IgE group. The IL-4 level in BAL fluid decreased in the high-dose anti-IgE, fluticasone+anti-IgE and anti-TNF groups. IgE levels increased in the BAL fluid in the high-dose anti-IgE and anti-TNF groups. The lymphocyte level increased in the BAL fluid in the high-dose anti-IgE group. The macrophage level decreased in the BAL fluid in the anti-TNF group. The relative expression of miRNA-126 increased in all groups. The relative expression of miRNA-133a decreased in the placebo and fluticasone groups. The relative expression of miRNA-133a increased in the low-dose anti-IgE, high-dose anti-IgE, fluticasone+anti-IgE and anti-TNF groups.

CONCLUSIONS

The results showed that anti-IgE is successful as a treatment. Fluticasone+anti-IgE and anti-TNF were seen to be superior to other therapeutic modalities when used for prophylaxis.

T2-low asthma: current approach to diagnosis and therapy

PURPOSE OF REVIEW

Asthma is a heterogeneous disease not only on a clinical but also on a mechanistic level. For a long time, the molecular mechanisms of asthma were considered to be driven by type 2 helper T cells (Th2) and eosinophilic airway inflammation; however, extensive research has revealed that T2-low subtypes that differ from the dominant T2 paradigm are also common.

RECENT FINDINGS

Research into asthma pathways has led to the recognition that some asthma phenotypes show absence of T2 inflammation or alternate between T2 and non-T2 responses. Moreover, numerous immune response modifiers that block key-molecules such as interleukin (IL)-5, IL-13, and immunoglobulin E (IgE) have been identified. Along the way, these studies pointed that T2-low inflammation may also be responsible for lack of responsiveness to current treatment regimes.

SUMMARY

Asthma pathogenesis is characterized by two major endotypes, a T2-high featuring increased eosinophilic airway inflammation, and a T2-low endotype presenting with either neutrophilic or paucigranulocytic airway inflammation and showing greater resistance to steroids. This clearly presents an unmet therapeutic challenge. A precise definition and characterization of the mechanisms that drive this T2-low inflammatory response in each patient phenotype is necessary to help identify novel drug targets and design more effective and targeted treatments.

Protective Role of Eosinophils and TNFa after Ozone Inhalation

Introduction

Exposure to ozone induces deleterious responses in the airways that include shortness of breath, inflammation, and bronchoconstriction. People with asthma have increased airway sensitivity to ozone and other irritants. Dr. Allison Fryer and colleagues addressed how exposure to ozone affects the immune and physiological responses in guinea pigs. Guinea pigs are considered a useful animal model for studies of respiratory and physiological responses in humans; their response to airborne allergens is similar to that in humans and shares some features of allergic asthma. Fryer and colleagues had previously observed that within 24 hours of exposure, ozone not only induced bronchoconstriction but also stimulated the production of new cells in the bone marrow, where all white blood cells develop. As a result of ozone exposure, increased numbers of newly synthesized white blood cells, particularly eosinophils, moved into the blood and lungs. The central hypothesis of the current study was that newly synthesized eosinophils recruited to the lungs 3 days after ozone exposure were beneficial to the animals because they reduced ozoneinduced bronchoconstriction. The investigators also hypothesized that the beneficial effect seen in normal (nonsensitized) animals was lost in animals that had been injected with an allergen, ovalbumin (sensitized). They also planned to explore the effects of inhibitors of certain cytokines (cellsignaling molecules). Immune responses in sensitized animals are dominated by a Th2 pattern, which is characterized by the synthesis of cytokines (interleukin [IL]-4, IL-5, and IL-13) and the Th2 subset of CD4+ T lymphocytes and the cells they activate (predominantly eosinophils, and B lymphocytes that switch to making immunoglobulin E [IgE]). Thus, sensitized animals were used as a model of allergic humans, whose immune responses tend to be dominated by IgE.

Approach

Fryer and colleagues exposed normal and sensitized (allergic) guinea pigs to 2 ppm ozone or filtered air for 4 hours and measured changes in cell numbers and airway responses 1 or 3 days later. They counted the numbers of eosinophils and other white blood cells (macrophages, neutrophils, and lymphocytes) in bone marrow, blood, and bronchoalveolar lung lavage fluid. The investigators also measured important physiological responses, including bronchoconstriction. Some animals were pretreated with etanercept and monoclonal anti-IL-5, which block tumor necrosis factor-a (TNFa) and IL-5, respectively. TNFa and IL-5 blockers have been used to treat patients with asthma. A key feature of the study was a technique to distinguish which white blood cells were synthesized after exposure from those that already existed, by injecting animals with bromodeoxyuridine (BrdU). BrdU is a thymidine analogue that is incorporated into the DNA of dividing cells, serving as a marker of newly produced cells. Therefore, a snapshot can be obtained of the proportion of newly synthesized (BrdU-positive) versus pre-existing (BrdU-negative) cell types.

Key results

1. Allergic and normal animals differed in the time course of bronchoconstriction and changes in cell types after ozone exposure. In normal animals, bronchoconstriction increased substantially at day 1 but decreased by day 3 after ozone exposure. In contrast, in allergic animals bronchoconstriction remained high at day 3. Ozone also increased the percentage of newly formed, BrdU2 positive eosinophils in the bone marrow and lungs of normal but not allergic animals. 2. Pretreatment with the TNFa blocker etanercept had complex effects, which differed between normal and allergic animals. In normal animals, etanercept decreased ozone-induced new synthesis of eosinophils in the bone marrow and blocked eosinophil migration to the lung; it also increased bronchoconstriction at day 3 (relative to day 1 without etanercept). In allergic animals, etanercept had no effect on any cell type in the bone marrow or lung after exposure to ozone and did not change bronchoconstriction compared with allergic animals not treated with etanercept. Etanercept tended to increase the numbers of blood monocytes and lymphocytes in air- and ozone-exposed normal and allergic animals at day 3, but had no effect on eosinophils in blood at this time point. This was one of the few statistically significant findings in the blood of exposed animals in the study. 3. Anti-IL-5 reduced bronchoconstriction at day 3 after exposure of allergic animals to ozone. In contrast, bronchoconstriction was greatly increased in normal animals treated with anti-IL-5.

Conclusions

Fryer and colleagues explored the airway and cellular responses in guinea pigs exposed to ozone. The HEI Review Committee, which conducted an independent review of the study, agreed that the findings supported the authors’ hypothesis (1) that exposure to ozone stimulates production of eosinophils in bone marrow, (2) that these newly formed eosinophils migrate to the lungs, and (3) that those eosinophils play a delayed but potentially beneficial role in reducing ozone-induced inflammation in the airways of healthy normal animals, but not in allergen-sensitized animals. The Committee also agreed that guinea pigs were a good model for studying responses to an allergen, because a major subtype of asthma (the high Th2 or allergic type) is associated with high levels of eosinophils in the blood. A novel finding was that the TNFa blocker etanercept decreased ozone-induced formation of eosinophils in the bone marrow and blocked eosinophil migration to the lung in normal animals. However, because injecting etanercept had little effect on eosinophils and did not decrease bronchoconstriction in allergic guinea pigs, the potential for treating patients with allergic asthma with TNFa blockers is uncertain. This is consistent with the poor performance of TNFa blockers in clinical studies of asthma treatment. Blocking the cytokine IL-5 with an anti-IL-5 antibody substantially decreased bronchoconstriction in sensitized animals. This suggests that therapies targeting IL-5 and eosinophils would be promising in at least some types of asthma. The Committee expressed caution toward experiments with cytokine blockers, both in animal models and humans, because such blockers are often not specific to a particular cell type and may differ at different sites in the body. Without further detailed confirmation of the effects of the blockers, interpreting these experiments can be challenging. The Committee concluded that the study by Fryer and colleagues raises several intriguing directions for future research, including exploring ways in which newly formed eosinophils differ from pre-existing ones, and how such findings apply to humans with allergy or asthma.

Baicalin attenuates inflammation in mice with OVA-induced asthma by inhibiting NF-κB and suppressing CCR7/CCL19/CCL21

Baicalin, extracted and purified from the Chinese medicinal plant, Scutellaria baicalensis Georgi (Huang qin in Chinese), exhibits potent anti-inflammatory activity against asthma. However, it remains unknown whether baicalin inhibits the activity of CC chemokine receptor 7 (CCR7) and its ligands, which are crucial for the initiation of airway inflammation. In the present study, we investigated the effects of baicalin on CCR7 and its ligands, CCL19 and CCL21, as well as on the nuclear factor-κB (NF-κB) pathway in a mouse model of asthma. A mouse model of acute asthma was established by exposing the mice to ovalbumin (OVA) (by intraperitoneal injection and inhalational challenge). Within 24 h of the final OVA challenge, lung function was detected by direct airway resistance analysis. Lung tissues were examined for pathological changes. Inflammatory cell counts in bronchoalveolar lavage fluid (BALF) were assessed. ELISA was utilized to evaluate the OVA-IgE, CCL19 and CCL21 levels in BALF. The interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels in serum were also detected by ELISA. The protein expression levels of CCR7, as well as that of phosphorylated IκBα (p-IκBα) and phosphorylated p65 (p-p65) were determined by western blot analysis and RT-qPCR was used to determine the CCR7 mRNA levels. Our data demonstrated that the oral administration of baicalin significantly improved pulmonary function and attenuated inflammatory cell infiltration into the lungs. Baicalin also decreased the levels of OVA-IgE, IL-6, TNF-α and CCR7, as well as those of its ligand, CCL19; the levels of NF-κB were also markedly suppressed by baicalin. The CCR7 mRNA level was substantially decreased. Our results thus suggest that baicalin exerts an inhibitory effect on airway inflammation, and this effect may be associated with the inhibition of CCR7 and CCL19/CCL21, which may provide new mechanistic insight into the anti‑inflammatory effects of baicalin.

Anti-inflammatory properties of pterocarpanquinone LQB-118 in mice

Pterocarpanquinone (+/-)-LQB-118 presents antineoplastic and antiparasitic properties and also shows great inhibitory effect on TNF-α release in vitro. Here, its anti-inflammatory activity was evaluated in a lipopolysaccharide (LPS)-induced lung inflammation model in C57BL/6 mice. LPS inhalation induced a marked neutrophil infiltration to the lungs which was reduced by intraperitoneal treatment with (+/-)-LQB-118 in a similar manner to that of dexamethasone and even better than that of acetylsalicylic acid. Moreover, (+/-)-LQB-118 administration resulted in decrease of NF-κB activation and KC level in lungs, with a pronounced inhibitory effect on TNF-α release, measured in bronchoalveolar lavage fluid. Trying to understand the anti-inflammatory mechanism by which (+/-)-LQB-118 acts, we performed a molecular modeling analysis, including docking to estrogen receptors α and β. Results suggested that (+/-)-LQB-118 may bind to both receptors, with a similar orientation to 17-β-estradiol. Together, these results showed that (+/-)-LQB-118 exhibits an anti-inflammatory effect, most likely by inhibiting TNF-α release and NF-κB activation, which may be related to the estrogen receptor binding.

TNF-α and Macrophages Are Critical for Respiratory Syncytial Virus-Induced Exacerbations in a Mouse Model of Allergic Airways Disease

Viral respiratory infections trigger severe exacerbations of asthma, worsen disease symptoms, and impair lung function. To investigate the mechanisms underlying viral exacerbation, we established a mouse model of respiratory syncytial virus (RSV)-induced exacerbation after allergen sensitization and challenge. RSV infection of OVA-sensitized/challenged BALB/c mice resulted in significantly increased airway hyperresponsiveness (AHR) and macrophage and neutrophil lung infiltration. Exacerbation was accompanied by increased levels of inflammatory cytokines (including TNF-α, MCP-1, and keratinocyte-derived protein chemokine [KC]) compared with uninfected OVA-treated mice or OVA-treated mice exposed to UV-inactivated RSV. Dexamethasone treatment completely inhibited all features of allergic disease, including AHR and eosinophil infiltration, in uninfected OVA-sensitized/challenged mice. Conversely, dexamethasone treatment following RSV-induced exacerbation only partially suppressed AHR and failed to dampen macrophage and neutrophil infiltration or inflammatory cytokine production (TNF-α, MCP-1, and KC). This mimics clinical observations in patients with exacerbations, which is associated with increased neutrophils and often poorly responds to corticosteroid therapy. Interestingly, we also observed increased TNF-α levels in sputum samples from patients with neutrophilic asthma. Although RSV-induced exacerbation was resistant to steroid treatment, inhibition of TNF-α and MCP-1 function or depletion of macrophages suppressed features of disease, including AHR and macrophage and neutrophil infiltration. Our findings highlight critical roles for macrophages and inflammatory cytokines (including TNF-α and MCP-1) in viral-induced exacerbation of asthma and suggest examination of these pathways as novel therapeutic approaches for disease management.

Human eosinophil activin A synthesis and mRNA stabilization are induced by the combination of IL-3 plus TNF

Eosinophils contribute to immune regulation and wound healing/fibrosis in various diseases including asthma. Growing appreciation for the role of activin A in such processes led us to hypothesize that eosinophils are a source of this TGF-β superfamily member. TNFα (TNF) induces activin A by other cell types and is often present at the site of allergic inflammation along with the eosinophil activating common β (βc) chain-signaling cytokines (IL-5, IL-3, GM-CSF). Previously, we established that the combination of TNF plus a βc chain-signaling cytokine synergistically induces eosinophil synthesis of the remodeling enzyme MMP-9. Therefore, eosinophils were stimulated ex vivo by these cytokines and in vivo through an allergen-induced airway inflammatory response. In contrast to IL-5+TNF or GM-CSF+TNF, the combination of IL-3+TNF synergistically induced activin A synthesis and release by human blood eosinophils. IL-3+TNF enhanced activin A mRNA stability, which required sustained signaling of pathways downstream of p38 and ERK MAP kinases. In vivo, following segmental airway allergen challenge of subjects with mild allergic asthma, activin A mRNA was upregulated in airway eosinophils compared to circulating eosinophils, and ex vivo, circulating eosinophils tended to release activin A in response to IL-3+TNF. These data provide evidence that eosinophils release activin A and that this function is enhanced when eosinophils are present in an allergen-induced inflammatory environment. Moreover, these data provide the first evidence for post-transcriptional control of activin A mRNA. We propose that, an environment rich in IL-3+TNF will lead to eosinophil–derived activin A, which plays an important role in regulating inflammation and/or fibrosis.

A human monoclonal anti-TNF alpha antibody (adalimumab) reduces airway inflammation and ameliorates lung histology in a murine model of acute asthma

BACKGROUND

A few experimental studies related to asthma have unveiled the beneficial effects of TNF alpha blocking agents on the airway histology, cytokine levels in bronchoalveolar lavage and bronchial hyper-responsiveness. In the current study, we aimed to assess the effect of adalimumab on the inflammation and histology of asthma in a murine model.

METHOD

Twelve-week-old BALB/c (H-2d/d) female rats (n=18) were allocated into three groups, including (group I) control (phosphate-buffered saline was implemented), (group II) asthma induced with OVA (n=6), and (group III) asthma induced with OVA+treated with adalimumab (n=6). Rats were executed on the 28th day of the study. The lung samples were fixed in 10% neutral buffered formalin. Lung parenchyma, alveolus, peribronchial and perivascular inflammation were assessed. Lung pathological scoring was performed.

RESULT

Severity of lung damage was found to be reduced significantly in the asthma induced with OVA+treated with adalimumab group. When compared with the untreated group, adalimumab significantly reduced the inflammatory cells around the bronchi and bronchioles, and reduced inflammation of the alveolar wall and alveolar wall thickness as well (median score=1, p=0.52). Peribronchial smooth muscle hypertrophy and oedema were significantly reduced after adalimumab administration.

CONCLUSION

Adalimumab (a human monoclonal anti-TNF alpha antibody) therapy significantly reduced the severity of lung damage by decreasing cellular infiltration and improvement on the lung histology in a murine model of acute asthma.

Hypereosinophilia and seroconversion of rheumatoid arthritis

At the intersection of atopy and autoimmunity, we present a patient with seronegative rheumatoid arthritis (RA) who developed hypereosinophilia, without evidence of other etiologies, as she became rheumatoid factor (RF) positive. Although the magnitude of eosinophilia in patients with RA has been thought to reflect the severity or activity of the RA, in our patient, eosinophilia developed at a time when the patient's synovitis was well controlled. Although eosinophilia may reflect associated drug hypersensitivity, discontinuation of the medications utilized to control our patient's disease, adalimumab and methotrexate, did not promote clinical improvement. Probably the most curious aspect of our patient was the concomitant development of rheumatoid factor seropositivity in the setting of previously seronegative RA. The temporal relationship between the development of peripheral eosinophilia and seroconversion suggests a possible connection between these events. We speculate that the T cell cytokine production that can induce eosinophilia may simultaneously activate RF production.

The effect of rhinovirus on airway inflammation in a murine asthma model

PURPOSE

The aim of the present study was to investigate the differences in lower airway inflammatory immune responses, including cellular responses and responses in terms of inflammatory mediators in bronchoalveolar lavage fluid (BALF) and the airway, to rhinovirus (RV) infection on asthma exacerbation by comparing a control and a murine asthma model, with or without RV infection.

METHODS

BALB/c mice were intraperitoneally injected with a crude extract of Dermatophagoides farinae (Df) or phosphate buffered saline (PBS) and were subsequently intranasally treated with a crude extract of Df or PBS. Airway responsiveness and cell infiltration, differential cell counts in BALF, and cytokine and chemokine concentrations in BALF were measured 24 hours after intranasal RV1B infection.

RESULTS

RV infection increased the enhanced pause (Penh) in both the Df sensitized and challenged mice (Df mice) and PBS-treated mice (PBS mice) (P<0.05). Airway eosinophil infiltration increased in Df mice after RV infection (P<0.05). The levels of interleukin (IL) 13, tumor necrosis factor alpha, and regulated on activation, normal T cells expressed and secreted (RANTES) increased in response to RV infection in Df mice, but not in PBS mice (P<0.05). The level of IL-10 significantly decreased following RV infection in Df mice (P<0.05).

CONCLUSION

Our findings suggest that the augmented induction of proinflammatory cytokines, Th2 cytokines, and chemokines that mediate an eosinophil response and the decreased induction of regulatory cytokines after RV infection may be important manifestations leading to airway inflammation with eosinophil infiltration and changes in airway responsiveness in the asthma model.

Aging predisposes to acute inflammatory induced pathology after tumor immunotherapy

Aging strongly promotes inflammation responses, which may predispose individuals after cancer therapies to lethal system toxicities and pathology that can be partially prevented by TNF blockade.

Cancer commonly occurs in the elderly and immunotherapy (IT) is being increasingly applied to this population. However, the majority of preclinical mouse tumor models assessing potential efficacy and toxicities of therapeutics use young mice. We assessed the impact of age on responses to systemic immune stimulation. In contrast to young mice, systemic cancer IT regimens or LPS given to aged mice resulted in rapid and lethal toxicities affecting multiple organs correlating with heightened proinflammatory cytokines systemically and within the parenchymal tissues. This inflammatory response and increased morbidity with age was independent of T cells or NK cells. However, prior in vivo depletion of macrophages in aged mice resulted in lesser cytokine levels, increased survival, and decreased liver histopathology. Furthermore, macrophages from aged mice and normal human elderly volunteers displayed heightened TNF and IL-6 production upon in vitro stimulation. Treatment of both TNF knockout mice and in vivo TNF blockade in aged mice resulted in significant increases in survival and lessened pathology. Importantly, TNF blockade in tumor-bearing, aged mice receiving IT displayed significant anti-tumor effects. These data demonstrate the critical role of macrophages in the age-associated hyper-inflammatory cytokine responses to systemic immunostimulation and underscore the importance of performing preclinical assessments in aged mice.

IgE cross-linking critically impairs human monocyte function by blocking phagocytosis

BACKGROUND

IgE cross-linking triggers many cellular processes that drive allergic disease. While the role of IgE in mediating allergic responses is best described on basophils and mast cells, expression of the high-affinity IgE receptor on other innate immune cells, including monocytes, suggests that it may affect the function of these cells in allergic environments.

OBJECTIVE

To determine the effect of IgE cross-linking on the function of human monocytes.

METHODS

Monocytes purified from healthy donor blood samples were cultured for 4 to 96 hours with media alone, a cross-linking anti-IgE antibody or control IgG. Surface CD14 and CD64 expression and secreted cytokine concentrations were determined. Monocyte function was determined by assessing (1) phagocytosis of Escherichia coli or apoptotic HEp2 cells and (2) killing of intracellular E coli. Select experiments were performed on monocytes obtained from participants with elevated versus normal serum IgE concentrations.

RESULTS

IgE cross-linking on monocytes increased CD14 expression and induced secretion of TNF-α, IL-6, and autoregulatory IL-10. These effects were greatest in individuals with elevated serum IgE concentrations. In contrast, IgE cross-linking reduced CD64 expression and significantly impaired phagocytic function without disrupting the capacity of monocytes to kill bacteria.

CONCLUSIONS

IgE cross-linking drives monocyte proinflammatory processes and autoregulatory IL-10 in a serum IgE-dependent manner. In contrast, monocyte phagocytic function is critically impaired by IgE cross-linking. Our findings suggest that IgE cross-linking on monocytes may contribute to allergic disease by both enhancing detrimental inflammatory responses and concomitantly crippling phagocytosis, a primary mechanism used by these cells to resolve inflammation.

The relationship of plasma aluminum to oxidant-antioxidant and inflammation status in asthma patients

Aluminum (Al) is a non-essential mineral which human beings are exposed to on day-to-day life. The purpose of this study was to assess the concentrations of plasma Al and the relationship of those levels with risk factors for asthma. In total, 27 allergic asthmatics and 30 healthy volunteers were enrolled. Plasma Al and selected blood parameters were measured, and a pulmonary function test was performed. Higher Al concentrations were found in the asthmatics than the healthy controls. Increased immunoglobulin E, high-sensitivity C-reactive protein, lipid peroxidation products, and pro-inflammatory cytokines (tumor necrosis factor-α and interleukin [IL]-4) were observed, but IL-10 and overall antioxidant and enzyme activities were lower. Associations between oxidative-antioxidant status and inflammatory markers with plasma Al levels in asthmatics were noted. Al status was also linked to cytokine concentrations and pulmonary function. In conclusion, abnormal Al distribution may further precipitate oxidative stress and inflammation, alter Th1/Th2 lymphocyte balance, and therefore contribute to the development of asthma.

Novel insights into mechanisms of food allergy and allergic airway inflammation using experimental mouse models

Over the last decades, considerable efforts have been undertaken in the development of animal models mimicking the pathogenesis of allergic diseases occurring in humans. The mouse has rapidly emerged as the animal model of choice, due to considerations of handling and costs and, importantly, due to the availability of a large and increasing arsenal of genetically modified mouse strains and molecular tools facilitating the analysis of complex disease models. Here, we review latest developments in allergy research that have arisen from in vivo experimentation in the mouse, with a focus on models of food allergy and allergic asthma, which constitute major health problems with increasing incidence in industrialized countries. We highlight recent novel findings and controversies in the field, most of which were obtained through the use of gene-deficient or germ-free mice, and discuss new potential therapeutic approaches that have emerged from animal studies and that aim at attenuating allergic reactions in human patients.

Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N'-nitro-N-nitroso-guanidine-treated mice or H(2)O(2)-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production.

TNF-α-induces airway hyperresponsiveness to cholinergic stimulation in guinea pig airways

BACKGROUND AND PURPOSE

TNF-α is an inflammatory cytokine implicated in the pathogenesis of asthma and it causes airway inflammation, bronchoconstriction and airway hyperresponsiveness to a number of spasmogens following inhalation.

EXPERIMENTAL APPROACH

We compared contractions of guinea pig isolated trachea incubated with saline or TNF-α for 1, 2 or 4 days to electrical field stimulation (EFS), 5-HT or methacholine. In addition, we compared bronchoconstriction in anaesthetized guinea pigs 6 h after intratracheal instillation of saline or TNF-α to vagal nerve stimulation, i.v. 5-HT or methacholine. Differential counts were performed on the bronchoalvelolar lavage fluid (BALF).

KEY RESULTS

Maximum contractions to methacholine, 5-HT and EFS were not different between freshly prepared and saline-incubated tissues. Exposure to TNF-α concentration-dependently potentiated contractions to 5-HT and EFS, but not methacholine. All contractions were atropine-sensitive, but not hexamethonium-sensitive. 5-HT-evoked contractions were inhibited by ketanserin or epithelial denudation. Only EFS-evoked contractions were tetrodotoxin-sensitive. Vagal stimulation, i.v. 5-HT or MCh caused a significant atropine-sensitive, frequency- and dose-dependent bronchoconstriction and decreased blood pressure similarly in both saline and TNF-α pre-treated animals. TNF-α potentiated the bronchoconstriction to vagal stimulation and 5-HT, but not MCh. The BALF from saline-treated animals contained predominantly macrophages, whereas that from TNF-α-treated animals contained neutrophils.

CONCLUSIONS AND IMPLICATIONS

TNF-α caused airway hyperresponsiveness to nerve stimulation in vivo and increased contractility in vitro. However, responsiveness to MCh was unchanged, suggesting a pre-synaptic action of TNF-α on parasympathetic nerves. TNF-α-induced airway hyperresponsiveness to 5-HT suggested an increased 5-HT(2A) receptor-mediated acetylcholine release from epithelial cells.

Induction of group IVC phospholipase A2 in allergic asthma: transcriptional regulation by TNFα in bronchoepithelial cells

Airway inflammation in allergen-induced asthma is associated with eicosanoid release. These bioactive lipids exhibit anti- and pro-inflammatory activities with relevance to pulmonary pathophysiology. We hypothesized that sensitization/challenge using an extract from the ubiquitous fungus Aspergillus fumigatus in a mouse model of allergic asthma would result in altered phospholipase gene expression, thus modulating the downstream eicosanoid pathway. We observed the most significant induction in the group IVC PLA2 (phospholipase A2) [also known as cPLA2γ (cytosolic PLA2γ) or PLA2G4C]. Our results infer that A. fumigatus extract can induce cPLA2γ levels directly in eosinophils, whereas induction in lung epithelial cells is most likely to be a consequence of TNFα (tumour necrosis factor α) secretion by A. fumigatus-activated macrophages. The mechanism of TNFα-dependent induction of cPLA2γ gene expression was elucidated through a combination of promoter deletions, ChIP (chromatin immunoprecipitation) and overexpression studies in human bronchoepithelial cells, leading to the identification of functionally relevant CRE (cAMP-response element), NF-κB (nuclear factor κB) and E-box promoter elements. ChIP analysis demonstrated that RNA polymerase II, ATF-2 (activating transcription factor 2)-c-Jun, p65-p65 and USF (upstream stimulating factor) 1-USF2 complexes are recruited to the cPLA2γ enhancer/promoter in response to TNFα, with overexpression and dominant-negative studies implying a strong level of co-operation and interplay between these factors. Overall, our results link cytokine-mediated alterations in cPLA2γ gene expression with allergic asthma and outline a complex regulatory mechanism.

Asthma translational medicine: report card

Over the last 30 years, scientific research into asthma has focused almost exclusively on one component of the disorder - airway inflammation - as being the key underlying feature. These studies have provided a remarkably detailed and comprehensive picture of the events following antigen challenge that lead to an influx of T cells and eosinophils in the airways. Indeed, in basic research, even the term "asthma" has become synonymous with a T helper 2 cell-mediated disorder. From this cascade of cellular activation processes and mediators that have been identified it has been possible to pinpoint critical junctures for therapeutic intervention, leading experimentalists to produce therapies that are very effective in decreasing airway inflammation in animal models. Many of these compounds have now completed early Phase 2 "proof-of-concept" clinical trials so the translational success of the basic research model can be evaluated. This commentary discusses clinical results from 39 compounds and biologics acting at 23 different targets, and while 6 of these drugs can be regarded as a qualified success, none benefit the bulk of asthma sufferers. Despite this disappointing rate of success, the same immune paradigm and basic research models, with a few embellishments to incorporate newly identified cells and mediators, continue to drive target identification and drug discovery efforts. It is time to re-evaluate the focus of these efforts.

Infliximab alleviates inflammation and ex vivo airway hyperreactivity in asthmatic E3 rats

Tumor necrosis factor-α (TNF-α) has been implicated in the pathogenesis of asthma, and neutralization of TNF-α is an effective therapy for inflammatory diseases. The present study tested the idea that a TNF-α antibody, infliximab, may be useful in the management of asthma. E3 rats were immunized with ovalbumin (OVA)/alum and received infliximab intra-peritoneally. Two weeks later, OVA-PBS was instilled intranasally daily for 7 days. Bronchoalveolar lavage fluids (BALFs), serum and lung homogenates were collected for analysis of cells and inflammatory mediators. Contractile responses of lobar-bronchus segments to agonists were functionally tested. Pulmonary tissues were investigated using histological examination. The results showed that the sensitized 'model E3 rats' exhibited an increase in the total amount of inflammatory cells, primarily eosinophils, in BALF and pulmonary tissue, as well as epithelial damage. Serum levels of IgE increased and so did the levels of nitric oxide, inducible nitric oxide synthase, TNF-α and IL-4, IL-5 and IL-13 in lung homogenate and serum. Furthermore, the contractile responses in bronchi induced by endothelin-1, sarafotoxin 6c and bradykinin increased and isoprenaline-induced relaxations decreased. All these changes induced by the sensitization procedure were reduced by the infliximab treatment. The results suggest that infliximab prevents the development of local airway inflammation and antagonizes changes of the bronchial smooth muscle receptor phenotype, thereby blocking the development of airway smooth muscle hyperreactivity of asthmatic rats.

Immunotherapy in asthma

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. Chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing, as well as variable airflow obstruction within the lung. With time, such airflow obstruction may become permanent due to remodeling. It has been treated for more than 100 years by subcutaneous immunotherapy with allergen extracts but in recent years, other forms and types of immunotherapy have been introduced. Perhaps the most successful of these to date, is sublingual immunotherapy, which has attained significant usage in European countries but has yet to make inroads into clinical practice in North America. Other mechanisms to modify the inflammatory responses of asthma have included immunotherapy with recombinant allergens, the use of allergen peptides targeting antigen-specific T cells and the administration of Toll-like receptor agonists coupled to allergen proteins. As the inflammatory responses in asthma frequently involve IgE, a modified monoclonal antibody to IgE and interfering with its binding to the IgE receptor have gained acceptance for treating severe allergic asthma. Other monoclonal antibodies or recombinant receptor antagonists are being assessed for their ability to block other contributors to the inflammatory response. Finally, attempts have been made to generate autoantibody responses to cytokines implicated in asthma. Most of these therapies aim to modify or inhibit the so-called Th 2 immune response, which is implicated in many forms of asthma, or to inhibit cytokines involved in these responses. However, an added benefit of classical immunotherapy seems to be the ability to prevent the allergic progression to new sensitivities and new forms of allergic disease.

What's new in asthma pathophysiology and immunopathology?

Research on asthma pathophysiology over the past decade has expanded the complex repertoire involved in the pathophysiology of asthma to include inflammatory, immune and structural cells, as well as a wide range of mediators. Studies have identified a role for connective and other mesenchymal tissues involved in airway remodeling. Recent findings have implicated the innate immune response in asthma and have revealed interesting patterns of interaction between the innate and adaptive immune response and the associated complex chronic inflammatory reaction. New immune cell populations have also been added to this repertoire, including Tregs, natural killer T cells and Th17 cells. The role of the eosinophil, a prominent pathological feature in most asthma phenotypes, has also been expanding to include roles such as tissue modifiers and immune regulators via a number of fascinating and hitherto unexplored mechanistic pathways. In addition, new and significant roles have been proposed for airway smooth muscle cells, fibroblasts, epithelial and endothelial cells. Tissue remodeling is now considered an integral element of asthma pathophysiology. Finally, an intricate network of mediators, released from both immune and inflammatory cells, including thymus stromal lymphopoietin and matrix metalloproteinases, have added to the complex milieu of asthma immunity and inflammation. These findings have implications for therapy and the search for novel strategies towards better disease management. Sadly, and perhaps due to the complex nature of asthma, advances in therapeutic discoveries and developments have been limited. Thus, understanding the precise roles played by the numerous dramatis personae in this odyssey, both individually and collectively within the context of asthma pathophysiology, continues to pose new challenges. It is clear that the next stage in this saga is to embark on studies that transcend reductionist approaches to involve system analysis of the complex and multiple variables involved in asthma, including the need to narrow down the phenotypes of this condition based on careful analysis of the organs (lung and airways), cells, mediators and other factors involved in bronchial asthma.

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.

Deficiency in the serum-derived hyaluronan-associated protein-hyaluronan complex enhances airway hyperresponsiveness in a murine model of asthma

BACKGROUND

Serum-derived hyaluronan (HA)-associated proteins (SHAPs), the heavy chains of inter-α-trypsin inhibitor, covalently bind to HA to form the SHAP-HA complex. The SHAP-HA complex is involved in the pathophysiology of inflammatory diseases, including rheumatoid arthritis. We investigated whether this complex is also involved in airway allergy.

METHODS

SHAP-HA-deficient (bikunin knockout, KO) mice and wild-type (WT) mice were immunized twice by intraperitoneal injection of ovalbumin (OVA) and exposed to aerosol OVA for 30 min each day for 2 weeks. Twenty-four hours after the final OVA challenge, airway responsiveness to inhaled methacholine (MCh) was measured, and analysis of bronchoalveolar lavage fluid (BALF) and lung histological studies were done.

RESULTS

Compared to WT mice, KO mice showed higher airway hyperresponsiveness to inhaled MCh and higher late-phase responses to OVA whereas the early-phase responses were similar. Cell differentials of BALF showed an increased number of macrophages and neutrophils in KO mice. Furthermore, decreased concentrations of soluble tumor necrosis factor receptor-1 (sTNFR1) were found in BALF from KO mice whereas the levels of Th1 and Th2 cytokines were not different from WT mice. Immunochemical study of the lung tissues revealed stronger staining of sTNFR1 in KO than in WT mice.

CONCLUSIONS

Our results suggest that in this murine asthma model, the SHAP-HA complex has an inhibitory role in the development of airway hyperresponsiveness and allergic airway inflammation which may be attributed, at least in part, to negative feedback mechanisms exerted by sTNFR1, the shedding of which from the cell surface might also be promoted by the SHAP-HA complex.

Cytokine antagonists for the treatment of asthma: progress to date

Asthma is a disease of the airways in which several cytokines such as interleukin (IL)-4, IL-5, IL-13 and tumor necrosis factor-alpha (TNFalpha) play a major role in the development and progression of inflammation, airway hyperresponsiveness, mucus production, and airway remodeling. The conventional anti-inflammatory therapies, represented by inhaled corticosteroids and antileukotrienes, are not always able to provide optimal disease control and it is therefore hoped that cytokine antagonists could achieve this goal in such situations. Anticytokine therapies have been tested in preclinical studies and some have entered clinical trials. Anti-IL-4 therapies have been tested in animal models of allergy-related asthma, but because of unclear efficacy their development was discontinued. However, IL-4/IL-13 dual antagonists and IL-13-specific blocking agents are more promising, as they exhibit more sustained anti-inflammatory effects. IL-5 antagonists have been found to be of limited efficacy in clinical studies but might be useful in conditions characterized by severe hypereosinophilia, and in which asthma is one of the disease manifestations. Unlike other chronic inflammatory conditions, such as rheumatoid arthritis, the use of anti-TNFalpha therapies in asthma might be limited by the unfavorable risk/benefit ratio associated with long-term use. The identification of so-called asthma TNFalpha phenotypes and perhaps the use of a less aggressive treatment regimen might address this important aspect. Other cytokine antagonists (for example for IL-9 or IL-25) are currently being evaluated in the asthma setting, and could open new therapeutic perspectives based on their efficacy and safety.

Golimumab for severe asthma

BACKGROUND

In severe asthma anti-TNF-alpha therapies might be effective in improving disease control based on preclinical results and on clinical short-term data. However, the long-term efficacy and safety is not known.

OBJECTIVE

To discuss the data on golimumab, an anti-TNF-alpha monoclonal antibody currently used in various forms of arthritis, evaluated as an add-on anti-inflammatory therapy in severe asthma.

METHODS/RESULTS

Critical appraisal of the efficacy and safety clinical data. Golimumab was not found to be generally efficacious and demonstrated an unfavourable risk-benefit ratio, but in some asthma subsets its better therapeutic effects might support its use provided the long-term safety is acceptable.

CONCLUSIONS

Although at first sight the safety and efficacy data of long-term use of golimumab in severe asthma might be unsupportive, in some disease subsets it might be really effective.

Anti-inflammatory and immunosuppressive effects of the enaminone E121

Asthma is a chronic inflammatory disease of the airways. The treatment of asthma is far from optimal and hence the need for novel therapeutic agents exists. The purpose of this study was to assess the anti-asthma effects of an enaminone, E121, and also its effects on human peripheral blood mononuclear cell proliferation and cytokine release. The effects of E121 were assessed in an ovalbumin-induced model of airway inflammation and airway hyperresponsiveness. In addition, the effects of E121 on phytohemagglutinin (PHA), anti-CD3 monoclonal antibody and lipopolysaccharide (LPS)-induced human peripheral blood mononuclear cell proliferation and cytokine release, respectively, were assessed. Treatment of mice with E121 significantly decreased the ovalbumin-induced increase in airway total cell influx and eosinophil infiltration and this was associated with an inhibition of ovalbumin-induced airway hyperresponsiveness. Moreover, E121 reduced PHA and anti-CD3-induced human peripheral blood mononuclear cell proliferation in vitro. E121 also inhibited PHA, anti-CD3 monoclonal antibody and LPS-induced cytokine release from human peripheral blood mononuclear cell cultures. These findings indicate that E121 exhibits anti-inflammatory and immunosuppressive activities.

Decrease in airway mucous gene expression caused by treatment with anti-tumor necrosis factor alpha in a murine model of allergic asthma

BACKGROUND

Mucous hypersecretion increases asthma morbidity and mortality. Tumor necrosis factor a (TNF-a) levels are elevated in bronchoalveolar fluid, sputum, and monocyte membranes in some patients with asthma. Anti-TNF-a decreased asthma exacerbations and improved forced expiratory volume in 1 second in these patients. Whether anti-TNF-a reduces mucous cell metaplasia or hyperplasia has not been evaluated.

OBJECTIVE

To investigate the role of anti-TNF-alpha in mucous hypersecretion.

METHODS

BALB/c mice sensitized intraperitoneally and challenged intratracheally with ovalbumin were treated with 250 microg of anti-TNF-alpha before ovalbumin sensitization and challenge or before only ovalbumin challenge. Control groups were sham treated. The tumor necrosis factor receptor (TNFR) mice (TNFR-/- and TNFR+/+) were identically sensitized and challenged. Seventy-two hours after the final challenge, the airway pressure time index (APTI), which measures airway hyperresponsiveness, was recorded. Mucous cell metaplasia was accessed by quantitative polymerase chain reaction for MUC-5AC (the epithelial cell mucous-inducing gene) and the percentage of periodic acid-Schiff (PAS) staining of bronchial epithelial cells. A human airway cell line (constitutively expressing MUC-5AC) was pretreated with a NF-kappaB inhibitor before TNF-alpha culture.

RESULTS

The mean (SE) fold change of MUC-5AC expression (compared with naive controls), the percentage of PAS-positive bronchiole epithelial cells, and the APTI decreased in BALB/c mice treated with anti-TNF-alpha before sensitization and challenge (4.9 [1.14], P = .007; 28.9% [6.8%], P < .001; and 545.8 [104.5] cm H2O/s, P < .001, respectively) and before challenge alone (9.3 [1.8], P = .03; 43.6% [10.7%], P = .009; and 896.8 [81.23] cm H2O/s, P = .06, respectively) compared with sham-treated mice (20.9 [3.9], 82.4% [1.8%], and 1,055 [30.6] cm H20/s, respectively). MUC-5AC expression decreased in ovalbumin sensitized or challenged TNFR-/- (2.41 [0.4]) compared with ovalbumin sensitized or challenged TNFR+/+ mice (18.4 [2.5], P < .001). TNF-alpha-induced MUC-5AC expression in human airway culture significantly decreased with pretreatment of a NF-kappaB inhibitor.

CONCLUSIONS

Anti-TNF-alpha treatment reduces airway mucous cell metaplasia in a mouse model of asthma, which may in part underlie its beneficial effect as asthma therapy.

Effects of TNF-alpha-converting enzyme inhibition on acute lung injury induced by endotoxin in the rat

We studied the effects of TNF-converting enzyme inhibition with Y-41654, which down-regulates the production of soluble TNF-alpha (sTNF-alpha), on acute lung injury induced by intratracheal administration of LPS. We first verified in vitro that pretreatment of isolated alveolar macrophages from Sprague-Dawley male rats with 20 microL of 0.1-mM Y-41654, decreased significantly (P < 0.05) the concentration of sTNF-alpha in cell supernatants induced by 10 microg/mL of LPS. We then studied four groups of rats (each n = 10) including 1) a control group, 2) an LPS group (300 microg /kg, instilled intratracheally), 3) a Y-41654 group, and 4) a treatment group treated with Y-41654 after LPS instillation. Y-41654, 10 mg/kg in 0.7 mL of phosphate-buffered saline, was administered (i.v.), 15 min before and 0.5, 1.5, 2.5, and 3.5 h after saline or LPS instillation. The animals were observed for 4 h. In the animals treated with Y-41654, the concentrations of sTNF-alpha and protein in bronchoalveolar lavage fluid, and the number of neutrophils in lung tissue and bronchoalveolar lavage fluid were significantly lower at 4 h than in the LPS group (P < 0.05). In conclusion, sTNF-alpha plays an important role in the development of acute lung injury induced by intratracheal administration of LPS, in part modulating neutrophil kinetics.

Inhibitory effect of eupatilin and jaceosidin isolated from Artemisia princeps on carrageenan-induced inflammation in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia princeps Pampanini (family Asteraceae) is an herbal medicine widely used as a hepatoprotective, antioxidative, anti-inflammatory, and antibacterial agent in Korea, China, and Japan.

AIM OF THE STUDY

This study aimed to elucidate the anti-inflammatory effect of the main constituents, eupatilin and jaceosidin, isolated from Artemisia princeps.

MATERIALS AND METHODS

We used carrageenan-induced inflammation in an air pouch on the back of mice and carrageenan-induced hind paw edema in rats to determine the anti-inflammatory effects of eupatilin and jaceosidin. Inflammatory makers, such as expression of pro-inflammatory cytokines and cyclooxygenase (COX)-2, and activation of nuclear factor-kappa B (NF-kappaB), were measured by enzyme-linked immunosorbent assays and immunoblot analyses.

RESULTS

Eupatilin and jaceosidin blocked carrageenan-induced increase in leukocyte number and protein levels in air pouch exudates. Eupatilin and jaceosidin inhibited COX-2 expression and NF-kappaB activation, and markedly reduced TNF-alpha, IL-1beta, and prostaglandin E2 (PGE(2)) levels. They also inhibited hind paw edema induced by carrageenan. Eupatilin and jaceosidin had similar activity.

CONCLUSIONS

These findings suggest that eupatilin and jaceosidin may reduce inflammation by inhibiting NF-kappaB activation, and that Artemisia princeps inhibits inflammation because of these constituents.

Etanercept prevents airway hyperresponsiveness by protecting neuronal M2 muscarinic receptors in antigen-challenged guinea pigs

BACKGROUND AND PURPOSE

Increased tumour necrosis factor-alpha (TNF-alpha) is associated with airway hyperreactivity in antigen-challenged animals. In human asthmatics, TNF-alpha is increased and blocking it prevents airway hyperreactivity in some asthmatic patients. However, the mechanisms by which TNF-alpha mediates hyperreactivity are unknown. Airway hyperreactivity can be caused by dysfunction of neuronal M(2) muscarinic receptors that normally limit acetylcholine release from parasympathetic nerves. Here we test whether blocking TNF-alpha receptors with etanercept prevents M(2) receptor dysfunction and airway hyperreactivity in antigen-challenged guinea pigs.

EXPERIMENTAL APPROACH

Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Some animals received etanercept (3 mg kg(-1) i.p.) 3 h before challenge. 24 h after challenge, airway hyperreactivity and M(2) receptor function were tested. Inflammatory cells in bronchoalveolar lavage, blood and lung were counted. TNF-alpha and its receptors were detected by real-time RT-PCR and immunocytochemistry in parasympathetic nerves from humans and guinea pigs and in human neuroblastoma cells.

KEY RESULTS

Antigen-challenged animals were hyperreactive to vagal stimulation and neuronal M(2) receptors were dysfunctional. Both M(2) receptor dysfunction and airway hyperreactivity were prevented by etanercept. Etanercept reduced eosinophils around airway nerves, and in blood, bronchoalveolar lavage and airway smooth muscle. Also, TNF-alpha decreased M(2) receptor mRNA in human and guinea pig parasympathetic neurons.

CONCLUSIONS AND IMPLICATIONS

Tumour necrosis factor-alpha may contribute to M(2) receptor dysfunction and airway hyperreactivity directly by decreasing receptor expression and indirectly by promoting recruitment of eosinophils, containing major basic protein, an M(2) antagonist. This suggests that etanercept may be beneficial in treatment of allergic asthma.

An investigation of the impact of the location and timing of antigen-specific T cell division on airways inflammation

It is widely accepted that allergic asthma is orchestrated by T helper type 2 lymphocytes specific for inhaled allergen. However, it remains unclear where and when T cell activation and division occurs after allergen challenge, and whether these factors have a significant impact on airways inflammation. We therefore employed a CD4-T cell receptor transgenic adoptive transfer model in conjunction with laser scanning cytometry to characterize the location and timing of T cell division in asthma in vivo. Thus, for the first time we have directly assessed the division of antigen-specific T cells in situ. We found that accumulation of divided antigen-specific T cells in the lungs appeared to occur in two waves. The first very early wave was apparent before dividing T cells could be detected in the lymph node (LN) and coincided with neutrophil influx. The second wave of divided T cells accumulating in lung followed the appearance of these cells in LN and coincided with peak eosinophilia. Furthermore, accumulation of antigen-specific T cells in the draining LN and lung tissue, together with accompanying pathology, was reduced by intervention with the sphingosine 1-phosphate receptor agonist FTY720 2 days after challenge. These findings provide greater insight into the timing and location of antigen-specific T cell division in airways inflammation, indicate that distinct phases and locations of antigen presentation may be associated with different aspects of pathology and that therapeutics targeted against leukocyte migration may be useful in these conditions.

Anti-TNF-alpha therapies in chronic obstructive pulmonary diseases

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and asthma are chronic diseases in which inflammation of the airways leads to progressive transient airway obstruction and TNF-alpha plays an important pro-inflammatory role.

OBJECTIVE

To assess the plausibility of anti-TNF-alpha therapies playing an anti-inflammatory role in asthma and COPD.

METHODS

Scientific rationale of TNF-alpha targeting in asthma and COPD was assessed individually and the available data on the use of anti-TNF-alpha in each disease were reviewed.

RESULTS AND CONCLUSION

Anti-TNF-alpha therapies demonstrate different efficacies in asthma and COPD and further supportive preclinical and clinical data are needed, especially about subsets of certain diseases which could benefit the most from these therapies.

Allergy and the nose

Allergic rhinitis (AR) is the most common immunological disorder and is characterized by an immunoglobulin E (IgE)-mediated inflammation induced by the allergen exposure. This review will consider some issues concerning pathophysiological aspects of AR: impact on asthma, response to decongestion, link with infections, response to specific immunotherapy, relationship with adiposity, effects on quality of life (QoL) and allergic inflammation. AR, even though not a serious illness, may be a clinically relevant disorder as it may present numerous complications and affect QoL, as reported in this review. Therefore, the management of AR patients should be rigorously careful and multi-disciplinary.