An Autophagy Modulator Peptide Prevents Lung Function Decrease and Corrects Established Inflammation in Murine Models of Airway Allergy.

The involvement of autophagy and its dysfunction in asthma is still poorly documented. By using a murine model of chronic house dust mite (HDM)-induced airway inflammation, we tested the expression of several autophagy markers in the lung and spleen of asthma-like animals. Compared to control mice, in HDM-sensitized and challenged mice, the expression of sequestosome-1/p62, a multifunctional adaptor protein that plays an important role in the autophagy machinery, was raised in the splenocytes. In contrast, its expression was decreased in the neutrophils recovered from the bronchoalveolar fluid, indicating that autophagy was independently regulated in these two compartments. In a strategy of drug repositioning, we treated allergen-sensitized mice with the therapeutic peptide P140 known to target chaperone-mediated autophagy. A single intravenous administration of P140 in these mice resulted in a significant reduction in airway resistance and elastance, and a reduction in the number of neutrophils and eosinophils present in the bronchoalveolar fluid. It corrected the autophagic alteration without showing any suppressive effect in the production of IgG1 and IgE. Collectively, these findings show that autophagy processes are altered in allergic airway inflammation. This cellular pathway may represent a potential therapeutic target for treating selected patients with asthma.

Disrupting Tryptophan in the Central Hydrophobic Region Selectively Mitigates Immunomodulatory Activities of the Innate Defence Regulator Peptide IDR-1002.

Innate defense regulator (IDR) peptides show promise as immunomodulatory therapeutics. However, there is limited understanding of the relationship of IDR peptide sequence and/or structure with its immunomodulatory activity. We previously reported that an IDR peptide, IDR-1002, reduces airway hyperresponsiveness (AHR) and inflammation in a house dust mite (HDM)-challenged murine model of airway inflammation. Here, we examined the sequence-to-function relationship of IDR-1002 in HDM-challenged mice and human bronchial epithelial cells (HBEC). We demonstrated that the tryptophan (W8) in the central hydrophobic region of IDR-1002 is required for the peptide to (i) suppress the pro-inflammatory cytokine IL-33, and induce anti-inflammatory mediators IL-1RA and stanniocalcin-1 in HBEC, and (ii) reduce IL-33 abundance, and eosinophil and neutrophil infiltration, in the lungs of HDM-challenged mice, without affecting the capacity to improve AHR, suggesting multimodal activity in vivo. Findings from this study can be used to design IDR peptides with targeted impact on immunomodulation and pathophysiology in respiratory diseases.

Tilianin attenuates HDM-induced allergic asthma by suppressing Th2-immune responses via downregulation of IRF4 in dendritic cells.

BACKGROUND: Acacetin 7-O-ß-D-glucoside (tilianin) is a major constituent of Agastache rugosa, a traditional medicine that has long been used for the treatment of gastrointestinal disorders. Tilianin has a wide variety of pharmacological properties such as cardioprotective, neuroprotective, and anti-atherogenic activities. We recently discovered that tilianin has the ability to suppress MUC5AC expression in vitro. In addition, we have established an in vivo model of allergic asthma using house dust mite (HDM) that can be applied to tilianin. PURPOSE: We investigated the effects of tilianin on airway inflammation in a HDM-induced asthma mouse model and associated mechanisms. METHODS: Tilianin was treated in splenocytes cultured in Th0 condition and HDM-stimulated bone marrow-derived dendritic cells (BMDCs), and their mRNA expression and cytokines production were determined by quantitative real-time PCR and ELISA. To evaluate the effects of tilianin in an allergic asthma model, mice were sensitized and challenged with HDM. Tilianin was administered prior to challenge by oral gavage and airway hyper-reactivity (AHR) to methacholine, inflammatory cell infiltration, cytokine levels, and airway remodeling were assessed. RESULTS: Tilianin inhibited the production of Th2-related cytokines in splenocytes, which play pivotal roles in allergic airway inflammation. When treated in HDM-stimulated BMDCs, tilianin decreased Th2-skewing cytokine IL-33 and transcription factor IRF4. On the contrary, tilianin increased Th1-skewing regulators, IL-12 and IRF1. In an HDM-induced asthmatic mouse model, tilianin attenuated AHR and airway inflammation. Tilianin suppressed the expression of Th2-related cytokines, IL-13 and IL-33 in lung tissues. As seen in HDM-stimulated BMDCs, tilianin also downregulated the expression of the transcription factor IRF4 but not IRF1. CONCLUSION: Taken together, these results suggest that tilianin attenuates HDM-induced allergic airway inflammation by inhibiting Th2-mediated inflammation through the selective inhibition of the IRF4-IL-33 axis in dendritic cells.

LncRNA OIP5­AS1 aggravates house dust mite­induced inflammatory responses in human bronchial epithelial cells via the miR­143­3p/HMGB1 axis.

Bronchial asthma poses a serious threat to human health. Previous studies have documented the role of long non­coding RNAs (lncRNAs) in asthma. However, the molecular mechanism underlying bronchial asthma remains unclear. The aim of the present study was to evaluate the role of the lncRNA Opa­interacting protein 5 antisense RNA1 (OIP5­AS1) in the house dust mite­induced inflammatory response in human bronchial epithelial cells. BEAS­2B cells were treated with Dermatophagoides pteronyssinus peptidase 1 (Der p1) to establish an in vitro model of asthma. OIP5­AS1 expression levels increased in BEAS­2B cells following Der p1 treatment, while microRNA (miR)­143­3p was downregulated. Additionally, the levels of the pro­inflammatory factors tumor necrosis factor­α, interleukin (IL)­6 and IL­8 were measured, and apoptosis was evaluated following OIP5 silencing. OIP5­AS1 knockdown reduced the inflammatory response and apoptosis in BEAS­2B cells. Furthermore, using dual luciferase reporter assays and co­transfection experiments, it was demonstrated that the function of OIP5­AS1 was mediated by miR­143­3p. miR­143­3p overexpression attenuated the Der p1­induced inflammatory response and apoptosis of BEAS­2B cells by targeting high mobility group box 1 (HMGB1). In summary, OIP5­AS1 exacerbated Der p1­induced inflammation and apoptosis in BEAS­2B cells by targeting miR­143­3p via HMGB1.

Update on House Dust Mite Allergen Avoidance Measures for Asthma.

PURPOSE OF REVIEW: To critically review the evidence in favor or against the use of house dust mite (HDM) allergen avoidance measures in patients with asthma. RECENT FINDINGS: Systematic reviews and meta-analyses suggested no positive effect of mite allergen avoidance strategies on asthma outcomes, resulting in a lack of consensus regarding the utility of these measures. However, such analyses have a number limitations and might not be the most adequate tool to evaluate current evidence and to derive clinical recommendations regarding mite allergen avoidance in asthmatic patients. We should not disproportionately rely on the results of meta-analyses and systematic reviews to inform clinical practice and asthma guidelines in this area. Recent high-quality evidence from randomized controlled trial in children confirmed that mite allergen-impermeable bed encasings reduce emergency hospital attendance with acute severe asthma exacerbations. Until better evidence is available, we suggest that physicians should adopt a pragmatic approach to mite allergen avoidance and advise sensitized patients to implement a multifaceted set of measures to achieve as great a reduction in exposure as possible. Potential predictors of positive response (e.g., patient's sensitization and exposure status) can pragmatically be evaluated using the size of skin test wheal or the titer of allergen-specific IgE. Finally, the intervention should be started as early as possible.

Crude Turmeric Extract Improves the Suppressive Effects of Lactobacillus rhamnosus GG on Allergic Inflammation in a Murine Model of House Dust Mite-Induced Asthma.

There is a strong correlation between dysregulation of the gastrointestinal microbiota and development of allergic diseases. The most prevalent therapies for relieving asthma symptoms are associated with serious side effects, and therefore novel approaches are needed. Our objective was to elucidate whether oral administration of Lactobacillus rhamnosus GG (LGG) as a probiotic or turmeric powder (TP) as a prebiotic or both as a synbiotic mitigate allergic inflammation including lung function, airway inflammatory cell infiltration, Th2 cytokines/chemokine in a murine model of house dust mite (HDM)-induced asthma. BALB/c mice were intranasally sensitized and challenged with HDM received TP (20 mg/Kg mouse), or/and LGG (105 or 107 cfu/ml), or both orally. Interestingly, the synbiotic intervention (HDM-TP-LGG E7) specifically suppress the developement of airway hyperresponsiveness in response to methacholine. Besides, our synbiotic, TP, and LGG strongly down-regulated eosinophilia, IL-5, CCL17, IL-13. In terms of T cell response, CD4+ Th2 cells and CD4+ Th17 population were reduced in the splenocytes of the treatment groups compared to control. The synbiotic group not only elevated CD25+Foxp3+Treg frequency compared to asthmatic group, but also increased T reg cells compared to the probiotic group. The synbiotic also indicated the superior effect in suppressing Th2 cells compared to probiotic. Although, TP and LGG alone displayed suppressive effects, this study showed that the combination therapy consisting of TP and LGG (synbiotic) is more effective in some of the parameters than either of the treatments alone. This novel synbiotic, might be considered as a potential food-based drug for translational medicine and can possibly be used along with corticosteroid treatment.

Efficacy and adherence of sublingual immunotherapy in patients aged 60 to 75 years old with house dust mite-induced allergic rhinitis.

PURPOSE: This study aimed to evaluate the efficacy and adherence of sublingual immunotherapy (SLIT) for house dust mite (HDM)-induced allergic rhinitis (AR) patients over 60 years old. MATERIALS AND METHODS: Eighty-six AR patients aged 60-75 years old were randomly divided in the control and treatment group as 1:1 ratio. The control group was treated with standard pharmacotherapy while the treatment group was treated with SLIT plus pharmacotherapy on demand. Patients adherence, combined symptom and medication score (CSMS), visual analog scale (VAS), and presence of adverse events were evaluated in the baseline and after 6-months, 12-months and 24-months treatment. RESULTS: Twenty-five (58.1%) subjects in the treatment group and 20 (46.5%) subjects in the control group completed the study (P > 0.05). The major reasons for premature cessation were out of touch and relieved symptoms. At the same time, CSMS and VAS of the patients over 60 years old in both groups significantly decreased from baseline to any post-baseline time point (all P < 0.05). The comparison of CSMS and VAS between the two groups revealed statistically significant differences in favor of the SLIT group at month 24 (P < 0.05), whereas no differences at month 6 and month 12 (all P > 0.05). CONCLUSION: 41.9% of the patients dropped out within 2 years of SLIT treatment and the major reasons for premature cessation were out of touch and relieved symptoms. This study suggested that SLIT plus pharmacotherapy provided a greater clinical benefit than pharmacotherapy alone at two years.

Semaphorin 3E Inhibits House Dust Mite-Induced Angiogenesis in a Mouse Model of Allergic Asthma.

Increased angiogenesis is a characteristic feature of remodeling in asthmatic airways and stems from the imbalance between pro-angiogenic and anti-angiogenic factors. Surprisingly, the factors regulating this process in allergic asthma are poorly defined. Previously, we showed an important role of semaphorins 3E (Sema3E) in growth factor-induced airway smooth muscle proliferation and migration in vitro, and in down-regulating airway inflammation, T helper 2/T helper 17 cytokine response, mucus cell hyperplasia, and airway hyperresponsiveness in vivo. However, the role of Sema3E in airway angiogenesis is not fully understood. Here, we investigated the role of Sema3E in airway angiogenesis using a house dust mite (HDM) murine model of allergic asthma. Intranasal treatment with recombinant Sema3E significantly reduced the expression of angiogenesis markers within the airways of HDM-challenged mice compared with untreated mice. HDM-induced expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 protein were diminished substantially on Sema3E treatment. Interestingly, Sema3E-treated mice showed an enhanced expression of the negative regulator of angiogenesis, soluble VEGF receptor 1, compared with the untreated mice. These events were reversed in Sema3E-deficient mice at baseline or on HDM challenge. Taken together, this study provides the first evidence that Sema3E modulates angiogenesis in allergic asthmatic airways via modulating pro- and anti-angiogenic factors.

High molecular weight hyaluronan ameliorates allergic inflammation and airway hyperresponsiveness in the mouse.

Allergic asthma is a major cause of morbidity in both pediatric and adult patients. Recent research has highlighted the role of hyaluronan (HA), an extracellular matrix glycosaminoglycan, in asthma pathogenesis. Experimental allergic airway inflammation and clinical asthma are associated with an increase of shorter fragments of HA (sHA), which complex with inter-α-inhibitor heavy chains (HCs) and induce inflammation and airway hyperresponsiveness (AHR). Importantly, the effects of sHA can be antagonized by the physiological counterpart high molecular weight HA (HMWHA). We used a mouse model of house dust mite-induced allergic airway inflammation and demonstrated that instilled HMWHA ameliorated allergic airway inflammation and AHR, even when given after the establishment of allergic sensitization and after challenge exposures. Furthermore, instilled HMWHA reduced the development of HA-HC complexes and the activation of Rho-associated, coiled-coil containing protein kinase 2. We conclude that airway application of HMWHA is a potential treatment for allergic airway inflammation.

Lung eosinophilia induced by house dust mites or ovalbumin is modulated by nicotinic receptor α7 and inhibited by cigarette smoke.

Eosinophilia (EOS) is an important component of airway inflammation and hyperresponsiveness in allergic reactions including those leading to asthma. Although cigarette smoking (CS) is a significant contributor to long-term adverse outcomes in these lung disorders, there are also the curious reports of its ability to produce acute suppression of inflammatory responses including EOS through poorly understood mechanisms. One possibility is that proinflammatory processes are suppressed by nicotine in CS acting through nicotinic receptor α7 (α7). Here we addressed the role of α7 in modulating EOS with two mouse models of an allergic response: house dust mites (HDM; Dermatophagoides sp.) and ovalbumin (OVA). The influence of α7 on EOS was experimentally resolved in wild-type mice or in mice in which a point mutation of the α7 receptor (α7E260A:G) selectively restricts normal signaling of cellular responses. RNA analysis of alveolar macrophages and the distal lung epithelium indicates that normal α7 function robustly impacts gene expression in the epithelium to HDM and OVA but to different degrees. Notable was allergen-specific α7 modulation of Ccl11 and Ccl24 (eotaxins) expression, which was enhanced in HDM but suppressed in OVA EOS. CS suppressed EOS induced by both OVA and HDM, as well as the inflammatory genes involved, regardless of α7 genotype. These results suggest that EOS in response to HDM or OVA is through signaling pathways that are modulated in a cell-specific manner by α7 and are distinct from CS suppression.

ITGB4 is essential for containing HDM-induced airway inflammation and airway hyperresponsiveness.

Airway epithelial cells play a significant role in the pathogenesis of asthma. Although the structural and functional defects of airway epithelial cells have been postulated to increase asthma susceptibility and exacerbate asthma severity, the mechanism and implication of these defects remain uncertain. Integrin ß4 (ITGB4) is a structural adhesion molecule that is downregulated in the airway epithelium of asthma patients. In this study, we demonstrated that ITGB4 deficiency leads to severe allergy-induced airway inflammation and airway hyper-responsiveness (AHR) in mice. After house dust mite (HDM) challenge, epithelial cell-specific ITGB4-deleted mice showed increased lymphocyte, eosinophil, and neutrophil infiltration into lung compared with that of the wild-type mice. ITGB4 deficiency also resulted in increased expression of the Th2 cytokine IL-4, IL-13, and the Th17 cytokine IL-17A in the lung tissue and in the T cells after HDM challenge. The aggravated inflammation in ITGB4 defect mice was partly caused by enhanced disrupted epithelial barrier integrity after HDM stress, which induced the increased thymic stromal lymphopoietin secretion from airway epithelial cells. This study therefore demonstrates that ITGB4 plays a pivotal role in containing allergen-mediated lung inflammation and airway hyper-responsiveness in allergic asthma.

A functional variant of miRNA-149 confers risk for allergic rhinitis and comorbid asthma in Chinese children.

The prevalence of allergic rhinitis (AR) and asthma has been increasing, and the comorbidity rates of these diseases are very high. Here, 176 AR patients, 124 patients with comorbid AR and asthma (AR-A) and 206 healthy Chinese children as controls were included in a case-control study. Six single-nucleotide polymorphisms (SNPs), miR-146a (rs2910164, rs57095329 and rs6864584), miR-196a2 (rs11614913), miR-499 (rs3746444) and miR-149 (rs2292832), were genotyped. The prevalence of homozygous miR-149 (rs2292832) CC genotype and C allele were considerably increased in AR and AR-A patients, compared with the controls. AR-A group showed higher frequencies of CC genotype and C allele of rs2292832 than AR group. No significant difference in the genotypic and allelic frequencies of other miRNA SNPs was found between the groups. MiR-149 levels in peripheral blood mononuclear cells (PBMCs) were significantly lower in CC (variant type) cases compared with TT (wild-type) cases. In further experiments, PBMCs obtained from the healthy controls with CC, CT and TT genotypes were stimulated by house dust mite extracts, which led to a significant decrease in the levels of miR-149 in PBMCs obtained from CC and TT individuals. This decrease was more pronounced in CC compared with TT cases. Our results demonstrate that miR-149 rs2292832 variant is not only strongly associated with AR and AR-A, but it may lead to an increase in the susceptibility to allergies following the stimulation with an allergen, through the changes in miR149 expression. Additionally, AR patients with CC genotypes were shown to be more susceptible to asthma.

Dermatophagoides pteronyssinus: changes in sensitisation in the past 11 years and comparison with other centres in Mexico

BACKGROUND: House dust mites are a ubiquitous air allergen in the human habitat. It has been shown that exposure to them is a fundamental factor in sensitisation and development of atopic disease. The objective of the study was to analyse changes in sensitisation to Dermatophagoides pteronyssinus (Der p.) in children treated in a tertiary level care hospital in Mexico City for a period of 11 years and compare with other studies carried out in Mexico. METHODS: A retrospective study was performed at the Hospital Infantil de México Federico Gómez (HIMFG). Information was gathered from skin tests for Der p. performed in the Allergy Laboratory from January 2004 to April 2015. Patients 2-18 years old who presented for examination of some type of allergic condition and who had immediate hypersensitivity tests to Der p. were included in the study. Results were compared with prior reports from other institutions. Descriptive analysis and 2 statistics were used. RESULTS: A total of 8794 patients were included in the study; 49.3% of the tests (95% CI 48-50) were positive for Der p. The percentage of monosensitised to mites was 2.7% for Der p. (95% CI 2-3). A significant difference was found between the results of older patients and those <6 years old. The frequency of sensitisation had a tendency to decrease during the 11 years analysed in all age groups. Conclusions and clinical relevance: The frequency of sensitisation to Der p. increased with age until reaching adolescence. In the last 11 years a decrease in sensitisation to this air allergen was observed

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Anti-angiogenic Nanotherapy Inhibits Airway Remodeling and Hyper-responsiveness of Dust Mite Triggered Asthma in the Brown Norway Rat.

Although angiogenesis is a hallmark feature of asthmatic inflammatory responses, therapeutic anti-angiogenesis interventions have received little attention. Objective: Assess the effectiveness of anti-angiogenic Sn2 lipase-labile prodrugs delivered via αvß3-micellar nanotherapy to suppress microvascular expansion, bronchial remodeling, and airway hyper-responsiveness in Brown Norway rats exposed to serial house dust mite (HDM) inhalation challenges. Results: Anti-neovascular effectiveness of αvß3-mixed micelles incorporating docetaxel-prodrug (Dxtl-PD) or fumagillin-prodrug (Fum-PD) were shown to robustly suppress neovascular expansion (p<0.01) in the upper airways/bronchi of HDM rats using simultaneous 19F/1H MR neovascular imaging, which was corroborated by adjunctive fluorescent microscopy. Micelles without a drug payload (αvß3-No-Drug) served as a carrier-only control. Morphometric measurements of HDM rat airway size (perimeter) and vessel number at 21d revealed classic vascular expansion in control rats but less vascularity (p<0.001) after the anti-angiogenic nanotherapies. CD31 RNA expression independently corroborated the decrease in airway microvasculature. Methacholine (MCh) induced respiratory system resistance (Rrs) was high in the HDM rats receiving αvß3-No-Drug micelles while αvß3-Dxtl-PD or αvß3-Fum-PD micelles markedly and equivalently attenuated airway hyper-responsiveness and improved airway compliance. Total inflammatory BAL cells among HDM challenged rats did not differ with treatment, but αvß3+ macrophages/monocytes were significantly reduced by both nanotherapies (p<0.001), most notably by the αvß3-Dxtl-PD micelles. Additionally, αvß3-Dxtl-PD decreased BAL eosinophil and αvß3+ CD45+ leukocytes relative to αvß3-No-Drug micelles, whereas αvß3-Fum-PD micelles did not. Conclusion: These results demonstrate the potential of targeted anti-angiogenesis nanotherapy to ameliorate the inflammatory hallmarks of asthma in a clinically relevant rodent model.

A review on emerging frontiers of house dust mite and cockroach allergy research

Currently, mankind is afflicted with diversified health issues, allergies being a common, yet little understood malady. Allergies, the outcome of a baffled immune system encompasses myriad allergens and causes an array of health consequences, ranging from transient to recurrent and mild to fatal. Indoor allergy is a serious hypersensitivity in genetically-predisposed people, triggered by ingestion, inhalation or mere contact of allergens, of which mite and cockroaches are one of the most-represented constituents. Arduous to eliminate, these aeroallergens pose constant health challenges, mostly manifested as respiratory and dermatological inflammations, leading to further aggravations if unrestrained. Recent times have seen an unprecedented endeavour to understand the conformation of these allergens, their immune manipulative ploys and other underlying causes of pathogenesis, most importantly therapies. Yet a large section of vulnerable people is ignorant of these innocuous-looking immune irritants, prevailing around them, and continues to suffer. This review aims to expedite this field by a concise, informative account of seminal findings in the past few years, with particular emphasis on leading frontiers like genome-wide association studies (GWAS), epitope mapping, metabolomics etc. Drawbacks linked to current approaches and solutions to overcome them have been proposed

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Plethysmography Phenotype QTL in Mice Before and After Allergen Sensitization and Challenge.

Allergic asthma is common airway disease that is characterized in part by enhanced airway constriction in response to nonspecific stimuli. Genome-wide association studies have identified multiple loci associated with asthma risk in humans, but these studies have not accounted for gene-environment interactions, which are thought to be important factors in asthma. To identify quantitative trait loci (QTL) that regulate responses to a common human allergen, we applied a house dust mite mouse (HDM) model of allergic airway disease (AAD) to 146 incipient lines of the Collaborative Cross (CC) and the CC founder strains. We employed a longitudinal study design in which mice were phenotyped for response to the bronchoconstrictor methacholine both before and after HDM sensitization and challenge using whole body plethysmography (WBP). There was significant variation in methacholine responsiveness due to both strain and HDM treatment, as reflected by changes in the WBP parameter enhanced pause. We also found that distinct QTL regulate baseline [chromosome (Chr) 18] and post-HDM (Chr 19) methacholine responsiveness and that post-HDM airway responsiveness was correlated with other features of AAD. Finally, using invasive measurements of airway mechanics, we tested whether the Chr 19 QTL affects lung resistance per se using C57BL/6J mice and a consomic strain but found that QTL haplotype did not affect lung resistance. We conclude that aspects of baseline and allergen-induced methacholine responsiveness are associated with genetic variation, and that robust detection of airway resistance QTL in genetically diverse mice will be facilitated by direct measurement of airway mechanics.

mRNA-Mediated Gene Supplementation of Toll-Like Receptors as Treatment Strategy for Asthma In Vivo.

Asthma is the most common chronic disease in childhood. Although several therapeutic options are currently available to control the symptoms, many drugs have significant side effects and asthma remains an incurable disease. Microbial exposure in early life reduces the risk of asthma and several studies have suggested protective effects of Toll-like receptor (TLR) activation. We showed previously that modified mRNA provides a safe and efficient therapeutic tool for in vivo gene supplementation. Since current asthma drugs do not take patient specific immune and TLR backgrounds into consideration, treatment with tailored mRNA could be an attractive approach to account for the patient's individual asthma phenotype. Therefore, we investigated the effect of a preventative treatment with combinations of Tlr1, Tlr2 and Tlr6 mRNA in a House Dust Mite-induced mouse model of asthma. We used chemically modified mRNA which is-in contrast to conventional viral vectors-non-integrating and highly efficient in gene transfer. In our study, we found that treatment with either Tlr1/2 mRNA or Tlr2/6 mRNA, but not Tlr2 mRNA alone, resulted in better lung function as well as reduced airway inflammation in vivo. The present results point to a potentially protective effect of TLR heterodimers in asthma pathogenesis.

PGE2-treated macrophages inhibit development of allergic lung inflammation in mice.

In healthy lungs, many macrophages are characterized by IL-10 production, and few are characterized by expression of IFN regulatory factor 5 (formerly M1) or YM1 and/or CD206 (formerly M2), whereas in asthma, this balance shifts toward few producing IL-10 and many expressing IFN regulatory factor 5 or YM1/CD206. In this study, we tested whether redressing the balance by reinstating IL-10 production could prevent house dust mite-induced allergic lung inflammation. PGE2 was found to be the best inducer of IL-10 in macrophages in vitro. Mice were then sensitized and challenged to house dust mites during a 2 wk protocol while treated with PGE2 in different ways. Lung inflammation was assessed 3 d after the last house dust mite challenge. House dust mite-exposed mice treated with free PGE2 had fewer infiltrating eosinophils in lungs and lower YM1 serum levels than vehicle-treated mice. Macrophage-specific delivery of PGE2 did not affect lung inflammation. Adoptive transfer of PGE2-treated macrophages led to fewer infiltrating eosinophils, macrophages, (activated) CD4(+), and regulatory T lymphocytes in lungs. Our study shows that the redirection of macrophage polarization by using PGE2 inhibits development of allergic lung inflammation. This beneficial effect of macrophage repolarization is a novel avenue to explore for therapeutic purposes.

High-level expression and purification of the major house dust mite allergen Der p 2 in Escherichia coli.

Der p 2, a major allergen derived from the house dust mite Dermatophagoides pteronyssinus, is one of the most clinically relevant allergens worldwide. Recombinant Der p 2 (rDer p 2) is useful in clinical diagnosis and disease-specific immunotherapy. However, previous studies showed that Der p 2 can only be expressed in Escherichia coli (E. coli) cells as inclusion bodies, thus protein refolding is required to obtain functional products. Here we report a new method to produce biologically active Der p 2 protein in E. coli. N-terminal hexahistidine- and trigger factor (TF)-tagged Der p 2 was expressed in soluble form in E. coli and purified using a combination of chromatography processes. This procedure produced milligram-level high purity Der p 2 per liter of bacterial culture. Moreover, far-UV region circular dichroism (CD) analysis and serum specific IgE reactivity test demonstrated that the secondary structure and IgE reactivity properties of rDer p 2 produced in our study were almost identical to those of natural Der p 2 (nDer p 2). In conclusion, the method developed in this work provides a useful tool for the production of immunologically active recombinant Der p 2 for clinical applications.