Human Allergic Asthma Research Articles

Understanding the Mouse Model of Respiratory Allergic Diseases

Respiratory allergic diseases, represented by allergic rhinitis and asthma, show various features due to their complex pathophysiology. Mouse models of respiratory allergic diseases replicate the characteristics of human allergic rhinitis and asthma, including airway inflammation airway hyperresponsiveness. Different phenotypes and immunologic features are shown according to the various strain of mouse; C57BL/6 strain and BALB/c strain are commonly used in allergic rhinitis and asthma. Ovalbumin as well as pathophysiologically relevant allergen, including house dust mite and fungus are generally used. The mouse model protocols usually include allergen sensitization period followed by allergen provocation period. Allergens possibly combined with adjuvant are introduced into mouse via intraperitoneal, subcutaneous, or intranasal route (sensitization period). Then, mouse repetitively inhales allergen by intranasal, intratracheal, or nebulized formation (aerosol), resulting in a robust influx of inflammatory cells in the airways (provocation period). We can evaluate several parameters including nasal rubbing and sneezing count, airway hyperresponsiveness, histological assessment, cellular composition, cytokine expression of nasal and lung tissue, and allergenspecific immunoglobulin of serum. These examinations provide useful information to understand the pathogenesis of allergic rhinitis and asthma and to test the safety and efficacy of new therapeutic agents. The present review analyzes several protocols and considerations as well as similarities and differences of mouse model of allergic rhinitis and asthma in detail.

Essential role of smooth muscle Rac1 in severe asthma associated-airway remodelling

Severe asthma is a chronic lung disease characterized by inflammation, airway hyperresponsiveness (AHR) and airway remodelling with hyperplasia of airway smooth muscle cells (aSMC). Small G proteins of the Rho family (RhoA, Rac1 and Cdc42) are key regulators of smooth muscle functions and we recently demonstrated that Rac1 controls bronchoconstriction. The objective of this study was to assess the role of Rac1 in severe asthma associated airway remodelling. We have studied the level of Rac1 activation by immunofluorescence in bronchial biopsies from severe asthmatic patients and control patients. In order to identify the role of Rac1 in aSMC remodelling, mice with specific deletion of Rac1 in SMC were sensitized to house dust mite to mimic the characteristics of severe allergic asthma in humans. Immunofluorescence analysis in human bronchial biopsies revealed an increased Rac1 activity in aSMC from severe asthmatic patients compared to control subjects. The basal proliferation rate of aSMC from severe asthmatics subjects is increased compared to control subjects. We have also observed that bFGF and PDGF-BB, growth factors described to be implicated in airway remodelling, stimulate the proliferation of aSMC from severe asthmatic subjects by 33% and 37% respectively. Moreover, the inhibition of Rac1 by EHT1864 decreased this proliferation by more than 50%. By a biochemical approach we have demonstrated that Rac1 signalling controlled human aSMC proliferation induced by mitogenic stimuli through the STAT3 signalling pathway. In vivo, we have demonstrated that specific deletion of Rac1 in SMC prevents aSMC hyperplasia and hypertrophy. This study demonstrates that Rac1 is overactive in the airways of patients with severe asthma and is essential for aSMC proliferation and airway remodelling. Inhibition of Rac1 dependant signalling pathway may represent an interesting target for the treatment of severe asthma.

Ceramide in apoptosis and oxidative stress in allergic inflammation and asthma

Nothing is known about the mechanisms by which increased ceramide levels in the lung contribute to allergic responses and asthma severity. We sought to investigate the functional role of ceramide in mouse models of allergic airway disease that recapitulate the cardinal clinical features of human allergic asthma. Allergic airway disease was induced in mice by repeated intranasal administration of house dust mite or the fungal allergen Alternaria alternata. Processes that can be regulated by ceramide and are important for severity of allergic asthma were correlated with ceramide levels measured by mass spectrometry. Both allergens induced massive pulmonary apoptosis and also significantly increased reactive oxygen species in the lung. Prevention of increases in lung ceramide levels mitigated allergen-induced apoptosis, reactive oxygen species, and neutrophil infiltration. In contrast, dietary supplementation of the antioxidant α-tocopherol decreased reactive oxygen species but had no significant effects on elevation of ceramide level or apoptosis, indicating that the increases in lung ceramide levels in allergen-challenged mice are not mediated by oxidative stress. Moreover, specific ceramide species were altered in bronchoalveolar lavage fluid from patients with severe asthma compared with in bronchoalveolar lavage fluid from individuals without asthma. Our data suggest that elevation of ceramide level after allergen challenge contributes to the apoptosis, reactive oxygen species generation, and neutrophilic infiltrate that characterize the severe asthmatic phenotype. Ceramide might be the trigger of formation of Creola bodies found in the sputum of patients with severe asthma and could be a biomarker to optimize diagnosis and to monitor and improve clinical outcomes in this disease.

Early Metabolic Syndrome (MetS) in Chronic Rhesus Macaque Model of Human Allergic Asthma

Human asthma, obesity, MetS, overt Type 2 diabetes, and related sequelae such as cardiovascular diseases, account for much of the mortality and morbidity worldwide. The etiology and complex physiological mechanisms underlying these pathological states intersect within the human body – and within Rhesus macaques. Much like humans, these animals (in captivity) often develop spontaneous, age‐related obesity. Hence, these animals are ideally suited for investigations of obesity and metabolism, as well as chronic allergic asthma.In 2013, twenty animals were sensitized by i.p. injection of house dust mite antigen (HDM) adsorbed to alum; airway sensitization and maintenance were accomplished by exposure to aerosolized HDM (aeroHDM) at ≥ 2‐week intervals, to a dose that induced an acute asthmatic response: ≥ 100% increase in lung resistance, ≥ 40% decrease in dynamic compliance, and/or peripheral oxygen saturation ≤ 70%. Periodically, we assessed the late phase asthmatic response 24 hours after aeroHDM exposure: airway hyperreactivity was assessed by aerosolized methacholine challenge; pulmonary inflammation was assessed by bronchoalveolar lavage. Occasionally animals were also exposed to an experimental asthma therapeutic.In 2018, ten animals had developed obesity and were suspected to harbor other clinical manifestations of MetS. Retrospective analyses confirmed relative hypertension in animals that had robust responsiveness to aeroHDM and were > 16 kg. Using archived frozen serum samples, we reconstructed the biochemical history of adiposity development and glucose metabolism ‐ a story that was evolving coincident with chronic exposures to both Diet A and aeroHDM (Fig. 1). By age 10 years, 4/5 of the largest animals (body weight, 21 ± 2 kg; waist circumference in lateral recumbency, 68 ± 5 cm; BMI using crown‐to‐rump length, 53 ± 3 kg/m2: values are mean ± SD) had insulin resistance (peak HOMA‐IR, 61 ± 29) associated with leptin > 14 ng/ml and total adiponectin < 3.5 μg/ml; 3/5 animals had dyslipidemia (Fig. 2); 1/5 animals had diabetes by age 8 years – 4 to 6 years earlier than would be expected based on non‐human primate literature. Biomarkers of inflammation and oxidative stress are outstanding.In July 2019, six months after switching to lower carbohydrate/higher protein Diet B, and > 12 months since the last aeroHDM exposure: all animals lost weight coincident with larger animals resolving insulin resistance, dyslipidemia, and diabetes. As seen in some obese asthmatic humans, larger animals had higher pulmonary inflammation (especially neutrophilic) and higher airway hyperreactivity to aerosolized methacholine.We concluded that chronic allergic inflammation synergized with inflammation of developing adiposity, accelerating onset of MetS in susceptible animals. We hypothesize that resumption of chronic periodic aeroHDM exposure will trigger more rapid progression/re‐establishment of MetS, IR, and eventually overt Type 2 diabetes if we do not intervene.Historical event timeline.Figure 1Body weight and serum triglycerides of 5 largest animals (mean ± SD: n=3 to 5 for each time point). Gray vertical bar: gradual transition to lower carbohydrate/higher protein Diet B.Figure 2

Similar immune mechanisms control experimental airway eosinophilia elicited by different allergens and treatment protocols

BackgroundMouse models have been extremely valuable in identifying the fundamental mechanisms of airway inflammation that underlie human allergic asthma. Several models are commonly used, employing different methods and routes of sensitisation, and allergens of varying clinical relevance. Although all models elicit similar hallmarks of allergic airway inflammation, including airway eosinophilia, goblet cell hyperplasia and cellular infiltration in lung, it is not established whether they do so by involving the same mechanisms.ResultsWe compared the impact of inactivation of various innate or adaptive immune genes, as well as sex, in different models of allergic airway inflammation in mice of C57BL/6 background. Chicken ovalbumin (OVA) and house dust mite (HDM) were used as allergens in settings of single or multiple intranasal (i.n.) challenges, after sensitisation in adjuvant or in adjuvant-free conditions. Eosinophil numbers in the broncho-alveolar lavage and lung histopathology were assessed in each model. We found that Major Histocompatibility Complex Class II (MHCII) deficiency and lack of conventional CD4+ T cells had the most profound effect, essentially ablating airway eosinophilia and goblet cell hyperplasia in all models. In contrast, Thymic stromal lymphopoietin receptor (TSLPR) deficiency greatly reduced eosinophilia but had a variable effect on goblet cells. CD1d deficiency and lack of Natural Killer T (NKT) cells moderately impaired inflammation in OVA models but not HDM, whereas sex affected the response to HDM but not OVA. Lastly, defective Toll-like receptor (TLR)4 expression had only a relatively modest overall impact on inflammation.ConclusionAll the models studied were comparably dependent on adaptive CD4+ T cell responses and TSLP. In contrast, sex, NKT cells and TLR4 appeared to play subtler and more variable roles that were dependent on the type of allergen and mode of immunization and challenge. These results are consistent with clinical data suggesting a key role of CD4+ T cells and TSLP in patients with allergic asthma.

Immunomodulatory asthma therapy in the equine animal model: A dose-response study and evaluation of a long-term effect.

IntroductionEquine asthma represents a naturally occurring animal model for human allergic neutrophilic asthma. Inhalative nanoparticle‐bound cytosine‐phosphate‐guanosine (CpG‐GNP) immunotherapy, independent of specific allergens, has already shown promising clinical and immunological results in previous studies and offers the possibility to treat the underlying cause of the disease. This study analyses the relationship between dose and response, and evaluates a possible long‐term effect.MethodsIn the prospective, randomised, double‐blind clinical field study, 29 horses suffering from equine asthma received 10 inhalation treatments with either 187.5 µg CpG‐GNP (CpG single dose [CpGsd]; n = 11), 375 µg CpG‐GNP double dose (CpG double dose [CpGdd]; n = 9) (q48h for 20 days) or 1600 µg beclomethasone (n = 9) (q24h for 10 days). Each horse was examined three times: before the treatment (I), immediately after the 10 inhalations (II), and 8 weeks after the final inhalation (III). The three groups were compared according to clinical and laboratory parameters. The study examined the sustainability of the long‐term effect of the treatment after 8 weeks, as well as the tolerability of the formula as a double dose.ResultsThe CpGsd resulted in a significant improvement in 82% of the parameters, the CpGdd in 72%. In the long‐term evaluation, the CpGsd showed a significant improvement in 100% of the parameters in comparison to the initial values, the CpGdd in 67%. On the immunological level, the bronchoalveolar lavage revealed a significant reduction of IL‐4, IL‐8, and interferon‐γ.ConclusionBoth CpG groups displayed significant improvements in clinical and laboratory parameters, especially regarding the long‐term effect of CpGsd. Doubling the CpG dose did not result in any improvement in comparison to the original single dose. On the immunological level, an anti‐inflammatory, as well as an immunomodulatory effect, apart from a Th2‐dominated immune response, could be observed. This immunomodulatory inhalation treatment could indicate a new possibility for human allergic asthma therapy.

The Combination Therapy of Dietary Galacto-Oligosaccharides With Budesonide Reduces Pulmonary Th2 Driving Mediators and Mast Cell Degranulation in a Murine Model of House Dust Mite Induced Asthma.

Background: Dietary non-digestible galacto-oligosaccharides (GOS) suppress allergic responses in mice sensitized and challenged with house dust mite (HDM). Budesonide is the standard therapy for allergic asthma in humans but is not always completely effective.Aim: To compare the efficacy of budesonide or different doses of GOS alone or with a combination therapy of budesonide and GOS on HDM-allergic responses in mice.Methods:BALB/c mice were sensitized and challenged with HDM, while fed a control diet or a diet supplemented with 1 or 2.5 w/w% GOS, and either or not oropharyngeally instilled with budesonide. Systemic and local inflammatory markers, such as mucosal mast cell protease-1 (mMCP-1) in serum, pulmonary CCL17, CCL22, and IL-33 concentrations and inflammatory cell influx in the bronchoalveolar lavage fluid (BALF) were determined.Results: Budesonide or GOS alone suppressed the number of eosinophils in the BALF of HDM allergic mice whereas budesonide either or not combined with GOS lowered both eosinophil and lymphocyte numbers in the BALF of HDM-allergic mice. Both 1 w/w% and 2.5 w/w% GOS and/or budesonide suppressed serum mMCP-1 concentrations. However, budesonide nor GOS alone was capable of reducing Th2 driving chemokines CCL17, CCL22 and IL-33 protein levels in supernatants of lung homogenates of HDM allergic mice, whereas the combination therapy did. Moreover, IL-13 concentrations were only significantly suppressed in mice treated with budesonide while fed GOS. A similar tendency was observed for the frequency of GATA3+CD4+ Th2 and CD4+RORγt+ Th17 cells in the lungs of the allergic mice.Conclusion: Dietary intervention using GOS may be a novel way to further improve the efficacy of anti-inflammatory drug therapy in allergic asthma by lowering Th2 driving mediators and mast cell degranulation.

Anti-Allergic Inflammatory Activity of Interleukin-37 Is Mediated by Novel Signaling Cascades in Human Eosinophils.

IL-1 family regulatory cytokine IL-37b can suppress innate immunity and inflammatory activity in inflammatory diseases. In this study, IL-37b showed remarkable in vitro suppression of inflammatory tumor necrosis factor-α, IL-1β, IL-6, CCL2, and CXCL8 production in the coculture of human primary eosinophils and human bronchial epithelial BEAS-2B cells with the stimulation of bacterial toll-like receptor-2 ligand peptidoglycan, while antagonizing the activation of intracellular nuclear factor-κB, PI3K–Akt, extracellular signal-regulated kinase 1/2, and suppressing the gene transcription of allergic inflammation-related PYCARD, S100A9, and CAMP as demonstrated by flow cytometry, RNA-sequencing, and bioinformatics. Results therefore elucidated the novel anti-inflammation-related molecular mechanisms mediated by IL-37b. Using the house dust mite (HDM)-induced humanized asthmatic NOD/SCID mice for preclinical study, intravenous administration of IL-37b restored the normal plasma levels of eosinophil activators CCL11 and IL-5, suppressed the elevated concentrations of Th2 and asthma-related cytokines IL-4, IL-6, and IL-13 and inflammatory IL-17, CCL5, and CCL11 in lung homogenate of asthmatic mice. Histopathological results of lung tissue illustrated that IL-37b could mitigate the enhanced mucus, eosinophil infiltration, thickened airway wall, and goblet cells. Together with similar findings using the ovalbumin- and HDM-induced allergic asthmatic mice further validated the therapeutic potential of IL-37b in allergic asthma. The above results illustrate the novel IL-37-mediated regulation of intracellular inflammation mechanism linking bacterial infection and the activation of human eosinophils and confirm the in vivo anti-inflammatory activity of IL-37b on human allergic asthma.

Psychosocial Stress and Immunity-What Can We Learn From Pig Studies?

Psychosocial stress may impair immune functions and provoke the development of pathologies. The underlying communication between the brain and the immune system is being studied predominantly in rodents. However, pigs offer several advantages as preclinical models for humans because pigs are more similar to humans than rodents in many anatomical and physiological characteristics. Unlike in rodents, the main stress-induced glucocorticoid in humans and pigs is cortisol with a similar circadian rhythm. In this study, we summarize data on short-term and long-term effects of social stress in pigs for their immunity and neuroendocrine regulation with consequences for their health and well-being. As typical social stressors, regrouping, crowding, social isolation, and maternal deprivation have been studied. Psychosocial stress in pigs may affect various reactions of innate and adaptive immunity, such as leukocyte distribution, cytokine secretion, lymphocyte proliferation, and antibody production as well as immune responses to viral infection or vaccination. Furthermore, social stress may induce or promote gastrointestinal diseases through dysregulation of inflammatory processes. In piglets, psychosocial stress may also result in glucocorticoid resistance of lymphocytes, which has been discussed as a cause of allergic asthma in humans. Stress-related neuroendocrine alterations in the cortico-limbic structures, such as the prefrontal cortex, amygdala, hippocampus and hypothalamus, have been demonstrated in pigs at different ages. Based on these data, we propose using pigs as models for psychosocial stress in humans to study the mechanisms of brain-to-immune and immune-to-brain communication from the systemic level down to the cellular and subcellular levels.

Plasticizer, di(2-ethylhexyl)phthalate (DEHP) enhances cockroach allergen extract-driven airway inflammation by enhancing pulmonary Th2 as well as Th17 immune responses in mice

In recent decades, there has been a gradual increase in the prevalence of asthma. Various factors including environmental pollutants have contributed to this phenomenon. Plasticizer, di(2-ethylhexyl)phthalate (DEHP) is one of the commonest environmental pollutants due to its association with plastic products. DEHP gets released from plastic products easily leading to respiratory exposure in humans. As a consequence, DEHP is associated with allergic asthma in humans and animals. DEHP is reported to act as an adjuvant in ovalbumin-induced mouse models of asthma at high doses. However, these studies mostly looked into the role of DEHP on Th2 cytokines/eosinophilic inflammation without investigating the role of airway epithelial cells (AECs)/dendritic cells (DCs)/Th17 cells. Its adjuvant activity with natural allergens such as cockroach allergens at tolerable daily intake needs to be explored. Cockroach allergens and DEHP may be inhaled together due to their coexistence in work place as well as household environments. Therefore, effect of DEHP was assessed in cockroach allergens extract (CE)-induced mouse model of asthma. Airway inflammation, histopathology, mucus secretion, and immune responses related to Th2/Th17/DCs and AECs were assessed in mice with DEHP exposure alone and in combination with CE. Our study shows that DEHP converts CE-induced eosinophilic inflammation into mixed granulocytic inflammation by promoting Th2 as well as Th17 immune responses. This was probably due to downregulation of E-cadherin in AECs, and enhancement of costimulatory molecules (MHCII/CD86/CD40)/pro-inflammatory cytokines (IL-6/MCP-1) in DCs by DEHP. This suggests that DEHP facilitates development of mixed granulocytic airway inflammation in the presence of a natural allergen.

A comparison of nanoparticullate CpG immunotherapy with and without allergens in spontaneously equine asthma-affected horses, an animal model.

IntroductionNew therapeutic strategies to modulate the immune response of human and equine allergic asthma are still under extensive investigation. Immunomodulating agents stimulating T‐regulatory cells offer new treatment options beyond conventional symptomatic treatment or specific immunotherapy for human and equine allergic airway diseases, with the goal of a homoeostatic T‐helper cell balance. The aim of this study was to evaluate the effects of a nebulized gelatin nanoparticle‐CpG formulation (CpG‐GNP) with and without specific allergens for the treatment of spontaneous allergic equine asthma as a model for human asthma.MethodsTwenty equine asthma‐affected horses were treated either with CpG‐GNP alone or CpG‐GNP with allergens. Two specific allergens were selected for each horse based on history and an in‐vitro test. Each horse received seven administrations of the respective nebulized composition and was examined before treatment, immediately after and 6 weeks after the treatment course.ResultsClinical parameters such as breathing rate, indirect interpleural measurement, arterial blood gases, amount of tracheal mucus and percentage of neutrophils and cytokines in tracheal washes and serum samples were evaluated. Treatment with CpG‐GNP alone as well as in combinations with relevant allergens resulted in clinical improvement of nasal discharge, breathing rate, amount of secretion and viscosity, neutrophil percentage and partial oxygen pressure directly after and 6 weeks after treatment. There were no significant differences between the two treatments in clinical parameters or local cytokine profiles in the tracheal wash fluid (IL‐10, IFN‐g, and IL‐17). IL‐4 concentrations decreased significantly in both groups.ConclusionNonspecific CpG‐GNP‐based immunotherapy shows potential as a treatment for equine and possibly also human allergic asthma.

Differential regulation of PD-1 and its ligands in allergic asthma.

Targeting PD-1/PD-1 ligand signalling is an established treatment option for cancer. The role of these molecules in allergic asthma has been investigated in several mouse studies yielding conflicting results. However, human studies investigating the expression and regulation of PD-1 and its ligands in allergic inflammation are lacking. To analyse the expression and regulation of PD-1 and its ligands in human allergic asthma. The well-established human asthma model of segmental allergen challenge (SAC) was used to analyse the regulation of PD-1 and its ligands PD-L1 and PD-L2 on T lymphocytes and dendritic cells by flow cytometry. The impact of immunoglobulin E (IgE)-mediated signalling on PD-L1 expression was analysed on isolated plasmacytoid dendritic cells (pDCs). PD-1 expression by blood CD4+ T cells was negatively associated with total and specific (against the allergen used for provocation) IgE serum concentrations. Twenty-four hours after SAC, a small decrease in endobronchial PD-1+ CD4+ T cells was accompanied by an increase in PD-L1 expression on endobronchial myeloid dendritic cells (mDCs) and pDCs. The PD-L1 up-regulation on pDCs was not induced by IgE-mediated mechanisms. In contrast, PD-L2 was only detected on endobronchial mDCs and was significantly down-regulated 24hours after SAC. This study shows, for the first time, an association of a low PD-1 expression by circulating CD4+ T cells with high total and specific (against the allergen used for provocation) IgE concentrations in allergic asthma. In addition, we demonstrate a differential regulation of PD-1 ligands on endobronchial DCs after allergen challenge which may favour Th2 inflammation. Therefore, modulating PD-1 ligand-mediated pathways might be a promising target in allergic asthma.

Lung responses in murine models of experimental asthma: Value of house dust mite over ovalbumin sensitization

Ovalbumin (OVA) sensitization has limitations in modelling asthma. Thus, we examined the value of allergic sensitization using a purified natural allergen, house dust mite (HDM), over the sensitization performed with OVA. Mice were sham-treated, or sensitized with OVA- or HDM with identical chronology. Airway resistance, tissue damping and elastance were assessed under control conditions and after challenging the animals with methacholine (MCh) and the specific allergen. Inflammatory profile of the bronchoalveolar lavage fluid was characterized and lung histology was performed. While no difference in the lung responsiveness to the specific allergen was noted, hyperresponsiveness to MCh was observed only in the HDM-sensitized animals in the lung peripheral parameters. Lung inflammation differed between the models, but excessive bronchial smooth muscle remodelling occurred only with OVA. In conclusion, we demonstrate that a purified natural allergen offers a more relevant murine model of human allergic asthma by expressing the key features of this chronic inflammatory disease both in the lung function and structure.

Identification of a plasma miRNA biomarker signature for allergic asthma: A translational approach.

Asthma is a heterogeneous chronic disease with different phenotypes and treatment responses. Thus, there is a high clinical need for molecular disease biomarkers to aid in differentiating these distinct phenotypes. As MicroRNAs (miRNAs), that regulate gene expression at the post-transcriptional level, are altered in experimental and human asthma, circulating miRNAs are attractive candidates for the identification of novel biomarkers. This study aimed to identify plasmatic miRNA-based biomarkers of asthma, through a translational approach. We prescreened miRNAs in plasma samples from two different murine models of experimental asthma (ovalbumin and house dust mite); miRNAs deregulated in both models were further tested in a human training cohort of 20 asthma patients and 9 healthy controls. Candidate miRNAs were then validated in a second, independent group of 26 asthma patients and 12 healthy controls. Ten miRNA ratios consisting of 13 miRNAs were differentially regulated in both murine models. Measuring these miRNAs in the training cohort identified a biomarker signature consisting of five miRNA ratios (7 miRNAs). This signature showed a good sensitivity and specificity in the test cohort with an area under the receiver operating characteristic curve (AUC) of 0.92. Correlation of miRNA ratios with clinical characteristics further revealed associations with FVC % predicted, and oral corticosteroid or antileukotriene use. Distinct plasma miRNAs are differentially regulated both in murine and in human allergic asthma and were associated with clinical characteristics of patients. Thus, we suggest that miRNA levels in plasma might have future potential to subphenotype patients with asthma.

Investigation and morphological observation of Suidasia breeding in flourmills in Huaibei

To investigate the Suidasia breeding in the flourmill and further observe its morphological characteristics. The samples were collected from different habitats of a flourmill and then separated, and the chipping was kept. The mites were selected and counted from the chipping under an optical microscope. The mites were made slide samples and identified. The mites were identified as Suidasia (including Suidasia nesbitti and Suidasia medanensis). A total of 20 samples were collected in this study, of which 13 were positively detected, with the detection rate of 65%. There were 2 876 mites of Suidasia that were detected from 200 g sample. The average breeding density was 14.38/g. It is common that Suidasia breeding in flour, which might cause human acariasis and allergic asthma. Therefore, the effective prevention measures should be taken.

A crucial role of the PD-1H coinhibitory receptor in suppressing experimental asthma.

Programmed death one homolog (PD-1H) is a cell surface molecule of the B7/CD28 immune modulatory gene family. Although PD-1H has been shown to function as a coinhibitory receptor on T cells to limit naive T-cell activation and proliferation, its role in the regulation of the T-cell response to allergens is unknown. We report here that genetic ablation or blockade of PD-1H drastically promotes pulmonary inflammation with massive accumulation of eosinophils in a mouse model of experimental asthma, indicating a suppressive function of PD-1H in allergic inflammation. The loss of PD-1H led to elevated production of both innate cytokines (IL-6, MCP-1 and TNFα) and Th2 cytokines (IL-5 and IL-13) in the lung, indicating a critical role of PD-1H in suppressing the production of airway inflammatory cytokines. In addition, the loss of PD-1H also impaired the expansion of systemic and pulmonary regulatory T cells during asthma induction. These findings support a critical role of intrinsic PD-1H in the regulation of inflammatory responses to allergens. Finally, we showed that treatment with a PD-1H agonistic monoclonal antibody reduced the severity of asthma, which was accompanied by suppressed lung inflammation. Our findings support PD-1H as a potential target and suggest a possible strategy for the treatment of allergic asthma in humans.

House dust mite exposure upregulates C3a receptor expression in pulmonary innate immune cells during the sensitization phase of allergic asthma by an IL-33-dependent mechanism

Abstract The anaphylatoxin C3a exerts its biologic functions through the activation of its cognate G-protein-coupled receptor C3a receptor (C3aR). C3aR mRNA expression has been described both in human and mouse lungs. However, no systematic analysis of C3aR expression at steady state and under pro-inflammatory conditions in the different pulmonary cell subsets has been done so far. Using a newly developed Tandem-dye (td)-Tomato-C3aR reporter knock-in mouse, we found C3aR expression in pulmonary eosinophils, resident CD11b+ conventional dendritic cells (cDC), and monocyte-derived DCs (moDC) at steady state. In contrast, pulmonary CD103+ cDCs and plasmacytoid DCs stained negative. Surprisingly, lung and bronchoalveolar alveolar macrophages (AMs), as well as neutrophils, lacked td-Tomato-C3aR. C3aR antibody staining revealed that only moDCs express the receptor at the cell surface. House dust mite (HDM) is a potent allergen that drives the development of allergic asthma in humans. Using the td-Tomato-C3aR reporter mouse, we found that HDM exposure resulted in the upregulation of C3aR in AMs, eosinophils, CD11b+ cDCs, and moDCs during the early phase of HDM-induced allergic asthma. Further, C3aR translocated to the cell surface in eosinophils and AMs following HDM exposure. Importantly, intra-tracheal administration of IL-33, an alarmin released by epithelial cells upon allergen contact, recapitulated these results. In summary, our findings demonstrate that allergen contact triggers the upregulation of C3aR and its surface expression in previously negative innate immune cells from the lung by an IL-33 dependent mechanism. C3aR-mediated activation of innate immune cells may play a critical role for early asthma development.

The IL-33/ST2 axis is crucial in type 2 airway responses induced by the Staphylococcus aureus protease SplD

Abstract Background Chronic airway inflammatory diseases such as chronic rhinosinusitis with nasal polyps and asthma showed increased nasal Staphylococcus aureus (S. aureus) colonization. Serine protease like protein D (SplD) and other closely related proteases secreted by S. aureus have recently been identified as inducers of allergic asthma in humans and mice but their mechanism of action is largely unknown Objective We investigated the role of recombinant SplD in driving Th2-biased responses and IgE formation in a murine model of allergic asthma. Methods Allergic asthma was induced in C57BL/6 J wild type mice, TLR4−/− mice and Rag2 Rag2−/− mice by repeated intratracheal applications of SplD. Inflammatory parameters in the airways were assessed by flow cytometry, ELISA, Luminex and immunofluorescence. Serum SplD-specific IgE levels were analysed by ELISA. Results We observed that repeated intratracheal exposure to SplD led to IL-33 and eotaxin production, eosinophilia, bronchial hyperreactivity and goblet cell hyperplasia in the airways. Blocking the IL-33 activity using a sST2 receptor significantly decreased the numbers of eosinophils, CD4+ T cells, and IL-5 and IL-13 production by lymph node cells but had no effect on IgE production. SplD-induced airway inflammation and IgE production were largely dependent on the presence of the functional adaptive immune system and independent of TLR4 signalling. Conclusion The S. aureus-derived protein SplD is a potent allergen of S. aureus and induces a Th2-biased inflammatory response in the airways in an IL-33-dependent, but TRL4-independent manner. sST2 could be an efficient strategy to interfere with SplD-induced Th2 inflammation, but does not prevent the allergic sensitization.

Targeted inhibition of Six1 attenuates allergic airway inflammation and remodeling in asthmatic mice.

Asthma is an inflammatory disease of the airways, characterized by lung eosinophilia, mucus hypersecretion by goblet cells and airway hyperresponsiveness to inhaled allergens. The purpose of this study was to evaluate the effects of Six1 on airway inflammation and remodeling and the underlying mechanisms in a murine model of chronic asthma. Female BALB/c mice were randomly divided into four groups: phosphate-buffered saline control, ovalbumin (OVA)-induced asthma group, OVA+siNC and OVA+siSix1. In this mice model, Six1 expression level was significantly elevated in OVA-induced asthma of mice. Additionally, downregulation of Six1 dramatically decreased OVA-challenged inflammation, infiltration, and mucus production. Moreover, silencing of Six1 resulted in decreased levels of immunoglobulin E and inflammatory mediators and reduced inflammatory cell accumulation, as well as inhibiting the expression of important mediators including matrix metalloproteinase MMP-2 and MMP-9, which is related to airway remodeling. Further analysis indicated that silencing of Six1 can significantly inhibit NF-kB pathway activation in the lungs. .In conclusion, these findings indicated that the downregulation of Six1 effectively inhibited airway inflammation and reversed airway remodeling, which suggest that Six1 represents a promising therapeutic strategy for human allergic asthma.

In Vitro effects of tamoxifen on equine neutrophils

Neutrophils participate in innate immunity as the first line of host defense against microorganisms. However, exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including allergic asthma and chronic obstructive pulmonary disease in humans, and equine asthma (also known as recurrent airway obstruction (RAO). Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effects on cell growth and survival. Previous preliminary studies showed that TX treatment in horses with induced acute pulmonary inflammation promoted early apoptosis of blood and BALF neutrophils, reduction of BALF neutrophils, and improvement in animals' clinical status. The aim of this study was to evaluate the in vitro effect of TX on functional tests in equine peripheral blood neutrophils. Chemotaxis, respiratory burst production and phagocytosis assays were performed on neutrophils isolated from peripheral blood samples from 10 healthy horses. Results showed that IL-8 stimulated cells decrease their chemotactic index when treated with TX (1 and 10μM). Respiratory burst production was also dampened after treatment with TX. In conclusion, these results confirm that tamoxifen has a direct action on equine peripheral blood neutrophils. However, more in vivo and in vitro studies are required to fully understand the mechanisms of action of TX on neutrophils, in order to elucidate if it can be used as treatment in disorders such as allergic asthma in humans and horses.