Spectrum of T-lymphocyte activities regulating allergic lung inflammation

Gene editing in allergic diseases: Identification of novel pathways and impact of deleting allergen genes

Gene editing technology has emerged as a powerful tool in all aspects of health research and continues to advance our understanding of critical and essential elements in disease pathophysiology. The clustered regularly interspaced short palindromic repeats (CRISPR) gene editing technology has been used with precision to generate gene knockouts, alter genes, and identify genes that cause disease. The full spectrum of allergic/atopic diseases, in part because of shared pathophysiology, is ripe for studies with this technology. In this way, novel culprit genes are being identified and allow for manipulation of triggering allergens to reduce allergenicity and disease. Notwithstanding current limitations on precision and potential off-target effects, newer approaches are rapidly being introduced to more fully understand specific gene functions as well as the consequences of genetic manipulation. In this review, we examine the impact of editing technologies of novel genes relevant to peanut allergy and asthma as well as how gene modification of common allergens may lead to the deletion of allergenic proteins.

β-glucan mitigates ovalbumin-induced airway inflammation by preventing oxidative stress and CD8+ T cell infiltration

BACKGROUND

Bronchial asthma is a severe respiratory condition characterized by airway inflammation, remodeling, and oxidative stress. β-Glucan (BG) is a polysaccharide found in fungal cell walls with powerful immunomodulatory properties. This study examined and clarified the mechanisms behind BG's ameliorativeactivitiesin an allergic asthma animal model.

METHOD

BG was extracted from Chaga mushroom and characterized using FT-IR, UV-visible, zeta potential, and 1H NMR analysis. The mice were divided into five groups, including control, untreated asthmatic, dexamethasone (Dexa)-treated (1 mg/kg), and BG (30 and 100 mg/kg)-treated groups.

RESULTS

BG treatment reduced nasal scratching behavior, airway-infiltrating inflammatory cells, and serum levels of IgE significantly. Additionally, BG attenuated oxidative stress biomarkers by lowering malonaldehyde (MDA) concentrations and increasing the levels of reduced glutathione (GSH), glutathione peroxidase (GPx), and catalase (CAT). Immunohistochemical and flow cytometric analyses have confirmed the suppressive effect of BG on the percentage of airway-infiltrating cytotoxic CD8+ T cells.

CONCLUSION

The findings revealed the role of CD8+ T cells in the pathogenesis of asthma and the role of BG as a potential therapeutic agent for asthma management through the suppression of airway inflammation and oxidative stress.

The impact of formaldehyde exposure on lung inflammatory disorders: Insights into asthma, bronchitis, and pulmonary fibrosis

Lung inflammatory disorders are a major global health burden, impacting millions of people and raising rates of morbidity and death across many demographic groups. An industrial chemical and common environmental contaminant, formaldehyde (FA) presents serious health concerns to the respiratory system, including the onset and aggravation of lung inflammatory disorders. Epidemiological studies have shown significant associations between FA exposure levels and the incidence and severity of several respiratory diseases. FA causes inflammation in the respiratory tract via immunological activation, oxidative stress, and airway remodelling, aggravating pre-existing pulmonary inflammation and compromising lung function. Additionally, FA functions as a respiratory sensitizer, causing allergic responses and hypersensitivity pneumonitis in sensitive people. Understanding the complicated processes behind formaldehyde-induced lung inflammation is critical for directing targeted strategies aimed at minimizing environmental exposures and alleviating the burden of formaldehyde-related lung illnesses on global respiratory health. This abstract explores the intricate relationship between FA exposure and lung inflammatory diseases, including asthma, bronchitis, allergic inflammation, lung injury and pulmonary fibrosis.

Anti-inflammation of LZTFL1 knockdown in OVA-induced asthmatic mice: Through ERK/GATA3 signaling pathway

Asthma is a common chronic respiratory disease characterized by Th2-type inflammation in the airways. Leucine zip transcription factor-like 1 (LZTFL1) has been implicated in the regulation of Th2-related factors. The knockdown of LZTFL1 resulted in decreased levels of IL-4, IL-5, and IL-13. We hypothesize that LZTFL1 may have an effect on asthma. We established an acute asthmatic mouse model using the Ovalbumin (OVA) sensitization, and we found that LZTFL1 expression was upregulated in OVA-induced CD4 + T cells. Mice challenged with OVA were administered 5 × 107 TU of lentivirus via tail vein injection. LZTFL1 knockdown reversed the frequency of sneezing and nose rubbing in OVA mice. LZTFL1 knockdown reduced inflammatory cell infiltration, reduced goblet cell numbers, and mitigated collagen deposition in lung tissue. LZTFL1 knockdown decreased the levels of OVA-specific IgE, IL-4, IL-5, and IL-13 in alveolar lavage fluid of asthmatic mice. Furthermore, LZTFL1 knockdown inhibited the aberrant activation of MEK/ERK signaling pathway in asthmatic mice. GATA binding protein 3 (GATA3) is an essential transcription factor in Th2 differentiation. Flow cytometry results revealed that LZTFL1 knockdown reduced the number of GATA3 + CD4 + Th2 cells, while it did not affect the stability of GATA3 mRNA. This may be attributed to ERK signaling which stabilized GATA3 by preventing its ubiquitination and subsequent degradation. In conclusion, LZTFL1 knockdown attenuates inflammation and pathological changes in OVA-induced asthmatic mice through ERK/GATA3 signaling pathway.

A bifurcated role for c-Maf in Th2 and Tfh2 cells during helminth infection

Differences in transcriptomes, transcription factor usage, and function have identified T follicular helper 2 (Tfh2) cells and T helper 2 (Th2) cells as distinct clusters of differentiation 4+",(CD4) T-cell subsets in settings of type-2 inflammation. Although the transcriptional programs driving Th2 cell differentiation and cytokine production are well defined, dependence on these classical Th2 programs by Tfh2 cells is less clear. Using cytokine reporter mice in combination with transcription factor inference analysis, the b-Zip transcription factor c-Maf and its targets were identified as an important regulon in both Th2 and Tfh2 cells. Conditional deletion of c-Maf in T cells confirmed its importance in type-2 cytokine expression by Th2 and Tfh2 cells. However, while c-Maf was not required for Th2-driven helminth clearance or lung eosinophilia, it was required for Tfh2-driven Immunoglobulin E production and germinal center formation. This differential regulation of cell-mediated and humoral immunity by c-Maf was a result of redundant pathways in Th2 cells that were absent in Tfh2 cells, and c-Maf-specific mechanisms in Tfh2 cells that were absent in Th2 cells. Thus, despite shared expression by Tfh2 and Th2 cells, c-Maf serves as a unique regulator of Tfh2-driven humoral hallmarks during type-2 immunity.

Translational Analysis of Moderate to Severe Asthma GWAS Signals Into Candidate Causal Genes and Their Functional, Tissue-Dependent and Disease-Related Associations

Asthma affects more than 300 million people globally and is both under diagnosed and under treated. The most recent and largest genome-wide association study investigating moderate to severe asthma to date was carried out in 2019 and identified 25 independent signals. However, as new and in-depth downstream databases become available, the translational analysis of these signals into target genes and pathways is timely. In this study, unique (U-BIOPRED) and publicly available datasets (HaploReg, Open Target Genetics and GTEx) were investigated for the 25 GWAS signals to identify 37 candidate causal genes. Additional traits associated with these signals were identified through PheWAS using the UK Biobank resource, with asthma and eosinophilic traits amongst the strongest associated. Gene expression omnibus dataset examination identified 13 candidate genes with altered expression profiles in the airways and blood of asthmatic subjects, including MUC5AC and STAT6. Gene expression analysis through publicly available datasets highlighted lung tissue cell specific expression, with both MUC5AC and SLC22A4 genes showing enriched expression in ciliated cells. Gene enrichment pathway and interaction analysis highlighted the dominance of the HLA-DQA1/A2/B1/B2 gene cluster across many immunological diseases including asthma, type I diabetes, and rheumatoid arthritis. Interaction and prediction analyses found IL33 and IL18R1 to be key co-localization partners for other genes, predicted that CD274 forms co-expression relationships with 13 other genes, including the HLA-DQA1/A2/B1/B2 gene cluster and that MUC5AC and IL37 are co-expressed. Drug interaction analysis revealed that 11 of the candidate genes have an interaction with available therapeutics. This study provides significant insight into these GWAS signals in the context of cell expression, function, and disease relationship with the view of informing future research and drug development efforts for moderate-severe asthma.

Identification of potential biomarkers and immune infiltration characteristics in severe asthma

OBJECTIVES

We hope to identify key molecules that can be used as markers of asthma severity and investigate their correlation with immune cell infiltration in severe asthma.

METHODS

An asthma dataset was downloaded from the Gene Expression Omnibus database and then processed by R software to obtain differentially expressed genes (DEGs). First, multiple enrichment platforms were applied to analyze crucial biological processes and pathways and protein-protein interaction networks related to the DEGs. We next combined least absolute shrinkage and selection operator logistic regression and the support vector machine-recursive feature elimination algorithms to screen diagnostic markers of severe asthma. Then, a local cohort consisting of 40 asthmatic subjects (24 with moderate asthma and 16 with severe asthma) was used for biomarker validation. Finally, infiltration of immune cells in asthma bronchoalveolar lavage fluid and their correlation with the screened markers was evaluated by CIBERSORT.

RESULTS

A total of 97 DEGs were identified in this study. Most of these genes are enriched in T cell activation and immune response in the asthma biological process. CC-chemokine receptor 7 (CCR7) and natural killer cell protein 7(NKG7) were identified as markers of severe asthma. The highest area under the ROC curve (AUC) was from a new indicator combining CCR7 and NKG7 (AUC = 0.851, adj. p < 0.05). Resting and activated memory CD4 T cells, activated NK cells, and CD8 T cells were found to be significantly higher in the severe asthma group (adj. p < 0.01). CCR7 and NKG7 were significantly correlated with these infiltrated cells that showed differences between the two groups. In addition, CCR7 was found to be significantly positively correlated with eosinophils (r = 0.38, adj. p < 0.05) infiltrated in bronchoalveolar lavage fluid.

CONCLUSION

CCR7 and NKG7 might be used as potential markers for asthma severity, and their expression may be associated with differences in immune cell infiltration in the moderate and severe asthma groups.

Ruxolitinib Ameliorates Airway Hyperresponsiveness and Lung Inflammation in a Corticosteroid-Resistant Murine Model of Severe Asthma

Asthma prevalence has increased considerably over the decades and it is now considered as one of the most common chronic disorders in the world. While the current anti-asthmatic therapies are effective for most asthma patients, there are 5-10% subjects whose disease is not controlled by such agents and they account for about 50% of the asthma-associated healthcare costs. Such patients develop severe asthma (SA), a condition characterized by a dominant Th1/Th17 cytokine response that is accompanied by Type 2 (T2)-low endotype. As JAK (Janus Kinase) signaling is very important for the activation of several cytokine pathways, we examined whether inhibition of JAKs might lessen the clinical and laboratory manifestations of SA. To that end, we employed a recently described murine model that recapitulates the complex immune response identified in the airways of human SA patients. To induce SA, mice were sensitized with house dust mite extract (HDME) and cyclic (c)-di-GMP and then subsequently challenged with HDME and a lower dose of c-di-GMP. In this model, treatment with the JAK inhibitor, Ruxolitinib, significantly ameliorated all the features of SA, including airway hyperresponsiveness and lung inflammation as well as total IgE antibody titers. Thus, these studies highlight JAKs as critical targets for mitigating the hyper-inflammation that occurs in SA and provide the framework for their incorporation into future clinical trials for patients that have severe or difficult-to manage asthma.

The significance of CYP11A1 expression in skin physiology and pathology

CYP11A1, a member of the cytochrome P450 family, plays several key roles in the human body. It catalyzes the first and rate-limiting step in steroidogenesis, converting cholesterol to pregnenolone. Aside from the classical steroidogenic tissues such as the adrenals, gonads and placenta, CYP11A1 has also been found in the brain, gastrointestinal tract, immune systems, and finally the skin. CYP11A1 activity in the skin is regulated predominately by StAR protein and hence cholesterol levels in the mitochondria. However, UVB, UVC, CRH, ACTH, cAMP, and cytokines IL-1, IL-6 and TNFα can also regulate its expression and activity. Indeed, CYP11A1 plays several critical roles in the skin through its initiation of local steroidogenesis and specific metabolism of vitamin D, lumisterol, and 7-dehydrocholesterol. Products of these pathways regulate the protective barrier and skin immune functions in a context-dependent fashion through interactions with a number of receptors. Disturbances in CYP11A1 activity can lead to skin pathology.

Salvinorin A inhibits ovalbumin-stimulated allergic rhinitis and RBL-2H3 cells degranulation

Allergic rhinitis (AR) is a long-term noncommunicable inflammatory disease of the nasal mucosa mediated by immunoglobulin E and is mainly caused by exposure of genetically susceptible individuals to environmental allergens. Mast cells contribute to the pathogenesis of allergic and nonallergic inflammatory diseases. Salvinorin A has been previously shown to inhibit leukotriene production and mast cell degranulation to suppress airway hyperresponsiveness caused by sensitization; thus, we hypothesized that salvinorin A has an anti-AR effect. We tested this hypothesis using monoclonal anti-2,4,6-dinitrophenyl immunoglobulin E/human serum albumin-induced rat basophilic leukemia cells (RBL-2H3 cells) and ovalbumin (OVA)-induced AR in mice as in vivo and in vitro AR models, respectively. The expression levels of histamine, β-hexosaminidase, interleukin-4 and tumor necrosis factor-α were decreased by salvinorin A in vitro. Granule release and F-actin organization were also suppressed by salvinorin A. Furthermore, salvinorin A inhibited OVA-induced features of AR in mice, including nasal rubbing and sneezing, as well as increased OVA-specific immunoglobulin E, histamine, tumor necrosis factor-α and interleukin-4 levels. In addition, salvinorin A decreased the phosphorylation of phosphoinositide 3-kinase/Akt in vitro and in vivo. Our work suggests that salvinorin A suppresses AR caused by sensitization by inhibiting the inflammatory responses of mast cells; thus, salvinorin A may have potential for treatment of AR.

Macrophage and dendritic cell subset composition can distinguish endotypes in adjuvant-induced asthma mouse models

Asthma is a heterogeneous disease with neutrophilic and eosinophilic asthma as the main endotypes that are distinguished according to the cells recruited to the airways and the related pathology. Eosinophilic asthma is the treatment-responsive endotype, which is mainly associated with allergic asthma. Neutrophilic asthma is a treatment-resistant endotype, affecting 5-10% of asthmatics. Although eosinophilic asthma is well-studied, a clear understanding of the endotypes is essential to devise effective diagnosis and treatment approaches for neutrophilic asthma. To this end, we directly compared adjuvant-induced mouse models of neutrophilic (CFA/OVA) and eosinophilic (Alum/OVA) asthma side-by-side. The immune response in the inflamed lung was analyzed by multi-parametric flow cytometry and immunofluorescence. We found that eosinophilic asthma was characterized by a preferential recruitment of interstitial macrophages and myeloid dendritic cells, whereas in neutrophilic asthma plasmacytoid dendritic cells, exudate macrophages, and GL7+ activated B cells predominated. This differential distribution of macrophage and dendritic cell subsets reveals important aspects of the pathophysiology of asthma and holds the promise to be used as biomarkers to diagnose asthma endotypes.

The Hygiene Hypothesis and New Perspectives-Current Challenges Meeting an Old Postulate

During its 30 years history, the Hygiene Hypothesis has shown itself to be adaptable whenever it has been challenged by new scientific developments and this is a still a continuously ongoing process. In this regard, the mini review aims to discuss some selected new developments in relation to their impact on further fine-tuning and expansion of the Hygiene Hypothesis. This will include the role of recently discovered classes of innate and adaptive immune cells that challenges the old Th1/Th2 paradigm, the applicability of the Hygiene Hypothesis to newly identified allergy/asthma phenotypes with diverse underlying pathomechanistic endotypes, and the increasing knowledge derived from epigenetic studies that leads to better understanding of mechanisms involved in the translation of environmental impacts on biological systems. Further, we discuss in brief the expansion of the Hygiene Hypothesis to other disease areas like psychiatric disorders and cancer and conclude that the continuously developing Hygiene Hypothesis may provide a more generalized explanation for health burden in highly industrialized countries also relation to global changes.

Extracellular Vesicles in Allergic Rhinitis and Asthma and Laboratory Possibilities for Their Assessment

Currently, extracellular vesicles (EVs) have been implicated in the etiopathogenesis of many diseases, including lung disorders, with the possibility of diagnostic and therapeutic applications. The analysis of EV in respiratory tract diseases faces many obstacles, including material collection from airways, standardization of isolation techniques, detection methods, the analysis of their content, etc. This review focuses on the role of extracellular vesicles in the pathogenesis of atopic respiratory diseases, especially asthma, with a special focus on their clinical applicability as a diagnostic tool. We also summarize available laboratory techniques that enable the detection of EVs in various biological materials, with particular emphasis on flow cytometry. The opportunities and limitations of detecting EV in bronchoalveolar lavage fluid (BALF) were also described.

RELATIONS BETWEEN ASTHMA AND OBESITY: AN ANALYSIS OF MULTIPLE FACTORS

OBJECTIVE

Asthma and obesity are prevalent and interrelated diseases. In the pediatric population, the effect of systemic inflammation associated to obesity, leading to inflammation of the airways, is currently controversial. Our aim was to compare inflammatory, clinical and spirometric patterns between children with asthma and obesity and those within the normal weight status range.

METHODS

A total of 79 boys and girls from 6 to 10 years old were selected and divided into four groups: obese asthmatics, non-obese asthmatics, obese non-asthmatics, and non-obese non-asthmatics. In addition to collecting clinical and anthropometric data, all children underwent spirometry and skin prick tests for inhalant allergens. Blood samples for measurement of cytokines and adipokines were also collected.

RESULTS

Obese asthmatics had significantly worse control of asthma than non-obese asthmatics (OR 4.9; 95%CI 1.1‒22.1), regardless of sex, physical activity and atopy. No differences in spirometry, Th1 and Th2 cytokines and adipokines levels were observed among the four groups. The prick tests were positive in 81.8 and 80% of non-obese asthmatics and obese asthmatics, respectively.

CONCLUSIONS

The degree of control of asthma was significantly lower in the obese group, regardless of the findings of no differences in spirometry. Extra-pulmonary factors could be responsible for this symptomatic profile. High positivity of skin test in both groups, which is considered a good marker of atopy, shows a preponderant atopic component in the genesis of asthma, both in children with obesity and in those within the normal weight status.

Mimicking Antigen-Driven Asthma in Rodent Models-How Close Can We Get?

Asthma is a heterogeneous disease with increasing prevalence worldwide characterized by chronic airway inflammation, increased mucus secretion and bronchial hyperresponsiveness. The phenotypic heterogeneity among asthmatic patients is accompanied by different endotypes, mainly Type 2 or non-Type 2. To investigate the pathomechanism of this complex disease many animal models have been developed, each trying to mimic specific aspects of the human disease. Rodents have classically been employed in animal models of asthma. The present review provides an overview of currently used Type 2 vs. non-Type 2 rodent asthma models, both acute and chronic. It further assesses the methods used to simulate disease development and exacerbations as well as to quantify allergic airway inflammation, including lung physiologic, cellular and molecular immunologic responses. Furthermore, the employment of genetically modified animals, which provide an in-depth understanding of the role of a variety of molecules, signaling pathways and receptors implicated in the development of this disease as well as humanized models of allergic inflammation, which have been recently developed to overcome differences between the rodent and human immune systems, are discussed. Nevertheless, differences between mice and humans should be carefully considered and limits of extrapolation should be wisely taken into account when translating experimental results into clinical use.

Acupoint application inhibits nerve growth factor and attenuates allergic inflammation in allergic rhinitis model rats

Background

Acupoint application therapy (AAT) has been widely used to treat allergic inflammation induced by allergic rhinitis (AR). The therapeutic effect of acupoint application is obvious. But the underlying therapeutic mechanism is still indistinct. Nerve growth factor (NGF) expression showed a dramatic rise in nasal mucosa tissue after AR, and allergic inflammation also increased significantly. To demonstrate how AAT can improve allergic inflammation by down-regulating the expression of NGF, AR rat models were established by intraperitoneal injection of ovalbumin (OVA) and nasal drops in SD rats. The number of nasal rubbing, sneezing and the degree of runny nose were observed and the symptoms were scored by behavioral symptom scoring method within 3 min. The expression levels of NGF and its downstream key proteins, such as IL-4, IL-5, IL-13, IgE and IFN-γ were determined by q-PCR, Western blot analysis, ELISA and immunofluorescence staining. Furthermore, H&E staining and toluidine blue staining were used to observe the pathological structure of nasal mucosa and mast cells in nasal mucosa, and the ultrastructure of nasal mucosa was observed by electron microscopy.

Results

Our data demonstrated that acupoint application significantly reduced the score of behavioral symptoms, and decreased the expression levels of NGF and its downstream key proteins, including IL-4, IL-5, IL-13, IgE, as well as promoting the expression level of IFN-γ in nasal mucosa tissue in AR rats. Thus, the activation of IgE and viability of mast cells was inhibited.

Conclusion

Our findings suggest that AAT can attenuate allergic inflammation by inhibiting the expression of NGF and its downstream pathway.

Extracellular vesicles and asthma: A review of the literature

Asthma is a chronic, recurrent and incurable allergy-related respiratory disease characterized by inflammation, bronchial hyperresponsiveness and narrowing of the airways. Extracellular vesicles (EVs) are a universal feature of cellular function and can be detected in different bodily fluids. Recent evidence has shown the possibility of using EVs in understanding the pathogenesis of asthma, including their potential as diagnostic and therapeutic tools. Studies have reported that EVs released from key cells involved in asthma can induce priming and activation of other asthma-associated cells. A literature review was conducted on all current research regarding the role and function of EVs in the pathogenesis of asthma via the PRISMA statement method. An electronic search was performed using EMBASE and PubMed through to November 2018. The EMBASE search returned 76 papers, while the PubMed search returned 211 papers. Following duplicate removal, titles and abstracts were screened for eligibility with a total of 34 studies included in the final qualitative analysis. The review found evidence of association between the presence of EVs and physiological changes characteristic of asthma, suggesting that EVs are involved in the pathogenesis, with the weight of evidence presently favouring deleterious effects of EVs in asthma. Numerous studies highlighted differences in exosomal contents between EVs of healthy and asthmatic individuals, which could be employed as potential diagnostic markers. In some circumstances, EVs were also found to be suppressive to disease, but more often promote inflammation and airway remodelling. In conclusion, EVs hold immense potential in understanding the pathophysiology of asthma, and as diagnostic and therapeutic markers. While more research is needed for definitive conclusions and their application in medical practice, the literature presented in this review should encourage further research and discovery within the field of EVs and asthma.

CD8+ Tc2 cells: underappreciated contributors to severe asthma

The complexity of asthma is underscored by the number of cell types and mediators implicated in the pathogenesis of this heterogeneous syndrome. Type 2 CD4⁺ T-cells (Th2) and more recently, type 2 innate lymphoid cells dominate current descriptions of asthma pathogenesis. However, another important source of these type 2 cytokines, especially interleukin (IL)-5 and IL-13, are CD8⁺ T-cells, which are increasingly proposed to play an important role in asthma pathogenesis, because they are abundant and are comparatively insensitive to corticosteroids. Many common triggers of asthma exacerbations are mediated via corticosteroid-resistant pathways involving neutrophils and CD8⁺ T-cells. Extensive murine data reveal the plasticity of CD8⁺ T-cells and their capacity to enhance airway inflammation and airway dysfunction. In humans, Tc2 cells are predominant in fatal asthma, while in stable state, severe eosinophilic asthma is associated with greater numbers of Tc2 than Th2 cells in blood, bronchoalveolar lavage fluid and bronchial biopsies. Tc2 cells strongly express CRTH2, the receptor for prostaglandin D2, the cysteinyl leukotriene receptor 1 and the leukotriene B4 receptor. When activated, these elicit Tc2 cell chemotaxis and production of chemokines and type 2 and other cytokines, resulting directly or indirectly in eosinophil recruitment and survival. These factors position CD8⁺ Tc2 cells as important and underappreciated effector cells contributing to asthma pathogenesis. Here, we review recent advances and new insights in understanding the pro-asthmatic functions of CD8⁺ T-cells in eosinophilic asthma, especially corticosteroid-resistant asthma, and the molecular mechanisms underlying their pathologic effector function.

Alongside Th2 and ILC2 cells, CD8⁺ T-cells are a cellular source of type 2 cytokines. We review recent findings and insights into the pathologic effector functions of type 2 CD8⁺ T-cells in eosinophilic asthma, especially steroid-resistant disease.http://bit.ly/2KbVGL2

Coptisine Suppresses Mast Cell Degranulation and Ovalbumin-Induced Allergic Rhinitis

Coptisine is one of the main components of isoquinoline alkaloids in the coptidis rhizome. The effect of coptisine on allergic rhinitis has not been investigated. In this study, we report the effects and mechanisms of coptisine using monoclonal anti-2,4,6-dinitrophenyl-immunoglobulin (Ig) E/human serum albumin (DNP-IgE/HSA)-stimulated rat basophilic leukemia cells (RBL-2H3 cells) in vitro and an ovalbumin (OVA)-induced allergic rhinitis (AR) in mice. The results showed that coptisine markedly decreased the levels of β-hexosaminidase, histamine, interleukin (IL)-4, and tumor necrosis factor (TNF)-α. Coptisine also prevented morphological changes, such as restoring an elongated shape, inhibiting granule release on toluidine blue staining, and reorganizing inhibited filamentous actins (F-actin). Additionally, coptisine blocked the phosphorylation of phosphoinositide3-kinase (PI3K)/Akt (as known as protein kinase B(PKB)) in RBL-2H3 cell. Furthermore, the results showed that coptisine suppressed OVA-induced allergic rhinitis symptoms, such as nasal rubbing and OVA-specific IgE, and histamine, IL-4 and TNF-α levels in the serum of AR mice. These data suggested that coptisine should have inhibitory effects on the inflammatory responses of mast cells, and may be beneficial for the development of coptisine as a potential anti-allergic drug.

Antigen-specific regulatory T-cell responses against aeroantigens and their role in allergy

The mucosal immune system of the respiratory tract is specialized to continuously monitor the external environment and to protect against invading pathogens, while maintaining tolerance to innocuous inhaled particles. Allergies result from a loss of tolerance against harmless antigens characterized by formation of allergen-specific Th2 cells and IgE. Tolerance is often described as a balance between harmful Th2 cells and various types of protective "regulatory" T cells. However, the identity of the protective T cells in healthy vs. allergic individuals or following successful allergen-specific therapy is controversially discussed. Recent technological progress enabling the identification of antigen-specific effector and regulatory T cells has significantly contributed to our understanding of tolerance. Here we discuss the experimental evidence for the various tolerance mechanisms described. We try to integrate the partially contradictory data into a new model proposing different mechanism of tolerance depending on the quality and quantity of the antigens as well as the way of antigen exposure. Understanding the basis of tolerance is essential for the rational design of novel and more efficient immunotherapies.

Propofol attenuates mast cell degranulation via inhibiting the miR-221/PI3K/Akt/Ca2+ pathway

The aim of the present study was to investigate the effect of propofol on immunoglobulin (Ig)E-activated mast cell degranulation and explore the underlying mechanisms responsible. RBL-2H3 cells were treated with propofol for at a variety of concentrations and different amounts of time. Cell viability was assessed using an MTT assay and microRNA (miR)-221 expression was quantified using reverse transcription-quantitative polymerase chain reaction. RBL-2H3 cells were transfected with miR-221 mimic or a negative control and degranulation, including the release of β-hexosaminidase and histamine, was evaluated using an ELISA kit. The effect of miR-221 overexpression on the phosphorylation of protein kinase B (Akt) was detected using western blotting and extracellular Ca²⁺ influx was measured via afura-2 assay. The phosphoinositide 3-kinase(PI3K) inhibitor LY294002 was used to investigate the association between PI3K/Akt signaling and Ca²⁺ influx in the presence of propofol. The results demonstrated that propofol treatment suppressed RBL-2H3 cell proliferation in a dose- and time-dependent manner. Propofol inhibited miR-221 expression in a dose-dependent manner compared with the control group; however, the inhibitive effect was significantly abrogated following transfection with miR-221 mimics. Furthermore, β-hexosaminidase and histamine release, PI3K/Akt signaling and Ca²⁺ influx were decreased following propofol application. miR-221 overexpression markedly ameliorated the suppressive effect of propofol. Treatment with LY294002 reversed the propofol-induced decrement of Ca²⁺ influx on IgE-mediated RBL-2H3 cells, suggesting an association between PI3K/Akt signaling and Ca²⁺ influx. In conclusion, the results of the present study suggest that propofol treatment attenuates mast cell degranulation via inhibiting the miR-221/PI3K/Akt/Ca²⁺ pathway. These results indicate that propofol may have a potential therapeutic effect as a treatment for allergic diseases.