A T cell-myeloid IL-10 axis regulates pathogenic IFN-γ-dependent immunity in a mouse model of type 2-low asthma

Therapeutic potential of a novel hybrid protein: Mitigating allergy and airway remodeling in chronic asthma models induced by Dermatophagoides pteronyssinus

BACKGROUND

The house-dust mite Dermatophagoides pteronyssinus is a key trigger of allergic asthma. Therefore, it is essential to develop new vaccines that can alter inflammatory processes and airway remodeling. The goal of this study was to test the hypoallergenic and immunogenic characteristics of the hypoallergen rDer p 2231 in a murine model of chronic asthma induced by D. pteronyssinus.

METHODS

For this, we measured the levels of IgE, IgG1, IgG2a, and cytokines produced by mice receiving the rDer p 2231 protein. Histopathological parameters of the chronic inflammatory response were also investigated by assessing inflammation and airway remodeling.

RESULTS

rDer p 2231 given as a therapeutic vaccine, led to a reduction in the production of IgE, eosinophils, and neutrophils, a lower activity of eosinophilic peroxidase in the airways, and an increase in the production of IgG1 and IgG2a antibodies. IgG antibodies blocked IgE binding to parental allergens in sera from atopic patients. Splenocytes, BALF, and lung from mice treated with rDer p 2231 secreted higher levels of Th1 and regulatory cytokines, as well as reduced levels of Th2 cytokines. Histopathological investigation of the lower airways demonstrated reductions in the thickness of the bronchiolar smooth muscle layer, in the subepithelial fibrosis, and in the goblet cells hyperplasia.

CONCLUSIONS

Our preclinical studies suggest that rDer p 2231 is a promising candidate for the treatment of D. pteronyssinus allergy, as the hypoallergen has demonstrated the ability to reduce IgE production, induce specific blocking antibodies, restore and balance Th1/Th2 immune responses, and significantly reduce airway remodeling factors. However, additional clinical studies are needed to more accurately assess the efficacy and safety of rDer p 2231 as a vaccine against D. pteronyssinus-induced allergy.

Regulation of inflammation by Interleukin-10 in the intestinal and respiratory mucosa

Intricate immune regulation is required at mucosal surfaces to allow tolerance to microbiota and harmless allergens and to prevent overexuberant inflammatory responses to pathogens. The cytokine Interleukin-10 (IL-10) is a key mediator of mucosal immune regulation. While IL-10 can be produced by virtually all cells of the immune system, many of its in vivo functions depend upon its production by regulatory or effector T cell populations and its signalling to macrophages, dendritic cells and specific T cell subsets. In this review, we discuss our current understanding of the role of IL-10 in regulation of immune responses, with a focus on its context-specific roles in intestinal homeostasis, respiratory infection and asthma. We highlight the importance of appropriate production and function of IL-10 for balancing pathogen clearance, control of microbiota and host tissue damage, and that precise modulation of IL-10 functions in vivo could present therapeutic opportunities.

Beyond CAR-T: The rise of CAR-NK cell therapy in asthma immunotherapy

Asthma poses a major public health burden. While existing asthma drugs manage symptoms for many, some patients remain resistant. The lack of a cure, especially for severe asthma, compels exploration of novel therapies. Cancer immunotherapy successes with CAR-T cells suggest its potential for asthma treatment. Researchers are exploring various approaches for allergic diseases including membrane-bound IgE, IL-5, PD-L2, and CTLA-4 for asthma, and Dectin-1 for fungal asthma. NK cells offer several advantages over T cells for CAR-based immunotherapy. They offer key benefits: (1) HLA compatibility, meaning they can be used in a wider range of patients without the need for matching tissue types. (2) Minimal side effects (CRS and GVHD) due to their limited persistence and cytokine profile. (3) Scalability for "off-the-shelf" production from various sources. Several strategies have been introduced that highlight the superiority and challenges of CAR-NK cell therapy for asthma treatment including IL-10, IFN-γ, ADCC, perforin-granzyme, FASL, KIR, NCRs (NKP46), DAP, DNAM-1, TGF-β, TNF-α, CCL, NKG2A, TF, and EGFR. Furthermore, we advocate for incorporating AI for CAR design optimization and CRISPR-Cas9 gene editing technology for precise gene manipulation to generate highly effective CAR constructs. This review will delve into the evolution and production of CAR designs, explore pre-clinical and clinical studies of CAR-based therapies in asthma, analyze strategies to optimize CAR-NK cell function, conduct a comparative analysis of CAR-T and CAR-NK cell therapy with their respective challenges, and finally present established novel CAR designs with promising potential for asthma treatment.

Advances in non-type 2 severe asthma: from molecular insights to novel treatment strategies

Asthma is a prevalent pulmonary disease that affects more than 300 million people worldwide and imposes a substantial economic burden. While medication can effectively control symptoms in some patients, severe asthma attacks, driven by airway inflammation induced by environmental and infectious exposures, continue to be a major cause of asthma-related mortality. Heterogeneous phenotypes of asthma include type 2 (T2) and non-T2 asthma. Non-T2 asthma is often observed in patients with severe and/or steroid-resistant asthma. This review covers the molecular mechanisms, clinical phenotypes, causes and promising treatments of non-T2 severe asthma. Specifically, we discuss the signalling pathways for non-T2 asthma including the activation of inflammasomes, interferon responses and interleukin-17 pathways, and their contributions to the subtypes, progression and severity of non-T2 asthma. Understanding the molecular mechanisms and genetic determinants underlying non-T2 asthma could form the basis for precision medicine in severe asthma treatment.

Obesity Enhances Non-Th2 Airway Inflammation in a Murine Model of Allergic Asthma

Obese patients with asthma present with aggravated symptoms that are also harder to treat. Here, we used a mouse model of allergic asthma sensitised and challenged to house dust mite (HDM) extracts to determine whether high-fat-diet consumption would exacerbate the key features of allergic airway inflammation. C57BL/6 mice were intranasally sensitised and challenged with HDM extracts over a duration of 3 weeks. The impact of high-fat-diet (HFD) vs. normal diet (ND) chow was studied on HDM-induced lung inflammation and inflammatory cell infiltration as well as cytokine production. HFD-fed mice had greater inflammatory cell infiltration around airways and blood vessels, and an overall more severe degree of inflammation than in the ND-fed mice (semiquantitative blinded evaluation). Quantitative assessment of HDM-associated Th2 responses (numbers of lung CD4+ T cells, eosinophils, serum levels of allergen-specific IgE as well as the expression of Th2 cytokines (Il5 and Il13)) did not show significant changes between the HFD and ND groups. Interestingly, the HFD group exhibited a more pronounced neutrophilic infiltration within their lung tissues and an increase in non-Th2 cytokines (Il17, Tnfa, Tgf-b, Il-1b). These findings provide additional evidence that obesity triggered by a high-fat-diet regimen may exacerbate asthma by involving non-Th2 and neutrophilic pathways.

Risk prediction model construction for asthma after allergic rhinitis by blood immune T effector cells

BACKGROUND

Allergic rhinitis (AR) and asthma (AS) are prevalent and frequently co-occurring respiratory diseases, with mutual influence on each other. They share similar etiology, pathogenesis, and pathological changes. Due to the anatomical continuity between the upper and lower respiratory tracts, allergic inflammation in the nasal cavity can readily propagate downwards, leading to bronchial inflammation and asthma. AR serves as a significant risk factor for AS by potentially inducing airway hyperresponsiveness in patients. Currently, there is a lack of reliable predictors for the progression from AR to AS.

METHODS

In this exhaustive investigation, we reexamined peripheral blood single cell RNA sequencing datasets from patients with AS following AR and healthy individuals. In addition, we used the bulk RNA sequencing dataset as a validation lineup, which included AS, AR, and healthy controls. Using marker genes of related cell subtype, signatures predicting the progression of AR to AS were generated.

RESULTS

We identified a subtype of immune-activating effector T cells that can distinguish patients with AS after AR. By combining specific marker genes of effector T cell subtype, we established prediction models of 16 markers. The model holds great promise for assessing AS risk in individuals with AR, providing innovative avenues for clinical diagnosis and treatment strategies.

CONCLUSION

Subcluster T effector cells may play a key role in post-AR AS. Notably, ACTR3 and HSPA8 genes were significantly upregulated in the blood of AS patients compared to healthy patients.

Lung proinflammatory microRNA and cytokine expression in a mouse model of allergic inflammation: role of sex chromosome complement and gonadal hormones

Epigenetic alterations such as dysregulation of miRNAs have been reported to play important roles in interactions between genetic and environmental factors. In this study, we tested the hypothesis that induction of lung inflammation by inhaled allergens triggers a sex-specific miRNA regulation that is dependent on chromosome complement and hormonal milieu. We challenged the four core genotypes (FCGs) model through intranasal sensitization with a house dust mite (HDM) solution (or PBS as a control) for 5 wk. The FCG model allows four combinations of gonads and sex chromosomes: 1) XX mice with ovaries (XXF), 2) XY mice with testes (XYM), 3) XX mice with testes (XXM), and 4) XY mice with ovaries (XYF). Following the challenge (n = 5-7/group), we assessed the expression of 84 inflammatory miRNAs in lung tissue using a PCR array and cytokine levels in bronchoalveolar lavage fluid (BAL) by a multiplex protein assay (n = 4-7 animals/group). Our results showed higher levels of the chemokine KC (an Il-8 homolog) and IL-7 in BAL from XYF mice challenged with HDM. In addition, IL-17A was significantly higher in BAL from both XXF and XYF mice. A three-way interaction among treatment, gonads, and sex chromosome revealed 60 of 64 miRNAs that differed in expression depending on genotype; XXF, XXM, XYF, and XYM mice had 45, 32, 4, and 52 differentially expressed miRNAs, respectively. Regulatory networks of miRNAs identified in this study were implicated in pathways associated with asthma. Female gonadal hormonal effects may alter miRNA expression and contribute to the higher susceptibility of females to asthma.NEW & NOTEWORTHY miRNAs play important roles in regulating gene and environmental interactions. However, their role in mediating sex differences in allergic responses and lung diseases has not been elucidated. Our study used a targeted omics approach to characterize the contributions of gonadal hormones and chromosomal components to lung responses to an allergen challenge. Our results point to the influence of sex hormones in miRNA expression and proinflammatory markers in allergic airway inflammation.

Endogenous inhibitory mechanisms in asthma

Endogenous inhibitory mechanisms promote resolution of inflammation, enhance tissue repair and integrity, and promote homeostasis in the lung. These mechanisms include steroid hormones, regulatory T cells, IL-10, prostaglandin E2, prostaglandin I2, lipoxins, resolvins, protectins, maresins, glucagon-like peptide-1 receptor, adrenomedullin, nitric oxide, and carbon monoxide. Here we review the most recent literature regarding these endogenous inhibitory mechanisms in asthma, which remain a promising target for the prevention and treatment of asthma.

B-cell-derived IL-10 promotes allergic sensitization in asthma regulated by Bcl-3

Aeroallergen sensitization, mainly mediated by lung epithelium and dendritic cells (DCs), is integral to allergic asthma pathogenesis and progression. IL-10 has a dual role in immune responses, as it inhibits myeloid cell activation but promotes B-cell responses and epithelial cell proliferation. Here, we report a proinflammatory function of B-cell-derived IL-10 modulated by Bcl-3 in allergic asthma. Specifically, Bcl-3-/- mice showed elevated IL-10 levels and were found to be highly vulnerable to allergic asthma induced by house dust mites (HDMs). IL-10 had a positive correlation with the levels of the DC chemoattractant CCL-20 in HDM-sensitized mice and in patients with asthma and induced a selective increase in CCL-20 production by mouse lung epithelial cells. Blockade of IL-10 or IL-10 receptors during sensitization dampened both HDM-induced sensitization and asthma development. IL-10 levels peaked 4 h post sensitization with HDM and IL-10 was primarily produced by B cells under Bcl-3-Blimp-1-Bcl-6 regulation. Mice lacking B-cell-derived IL-10 displayed decreased lung epithelial CCL-20 production and diminished DC recruitment to the lungs upon HDM sensitization, thereby demonstrating resistance to HDM-induced asthma. Moreover, responses to HDM stimulation in Bcl-3-/- mice lacking B-cell-derived IL-10 were comparable to those in Bcl-3+/+ mice. The results revealed an unexpected role of B-cell-derived IL-10 in promoting allergic sensitization and demonstrated that Bcl-3 prevents HDM-induced asthma by inhibiting B-cell-derived IL-10 production. Thus, targeting the Bcl-3/IL-10 axis to inhibit allergic sensitization is a promising approach for treating allergic asthma. IL-10 is released rapidly from lung plasma cells under Bcl-3-Blimp-1-Bcl-6 regulation upon house dust mite exposure and amplifies lung epithelial cell (EC)-derived CCL-20 production and subsequent dendritic cell (DC) recruitment to promote allergic sensitization in asthma.

Intrapulmonary IFN-γ instillation causes chronic lymphocytic inflammation in the spleen and lung through the CXCR3 pathway

Some patients with chronic refractory cough have high levels of pulmonary IFN-γ and IFN-γ-producing T lymphocytes. Pulmonary IFN-γ administration causes acute airway lymphocytic inflammation and cough hypersensitivity by increasing the number of pulmonary IFN-γ-producing T lymphocytes, but these lymphocytes may be recruited from other organs. Intraperitoneal IFN-γ injection can increase the spleen weight of mice. It remains elusive whether pulmonary IFN-γ can induce chronic airway lymphocytic inflammation and cough hypersensitivity by stimulating the proliferation of IFN-γ -producing T lymphocytes in the spleen. Here, we found that pulmonary IFN-γ administration induced chronic airway inflammation and chronic cough hypersensitivity with an increased number of IFN-γ-producing T lymphocytes in the spleen, blood and lung. Pulmonary IFN-γ administration also increased 1) the proliferation of spleen lymphocytes in vivo and 2) the IP-10 level and CXCR3+ T lymphocyte numbers in the spleen and lung of mice. IP-10 could promote the proliferation of spleen lymphocytes in vitro but not blood lymphocytes or lung-resident lymphocytes. AMG487, a potent inhibitor of binding between IP-10 and CXCR3, could block pulmonary IFN-γ instillation-induced chronic airway lymphocytic inflammation and the proliferation of IFN-γ-producing T lymphocytes in mouse spleens. In conclusion, intrapulmonary IFN-γ instillation may induce the proliferation of splenic IFN-γ-producing T lymphocytes through IP-10 and the CXCR3 pathway. The IFN-γ-producing T lymphocytes in blood, partly released from the mouse spleen, may be partly attracted to the lung by pulmonary IP-10 through the CXCR3 pathway. IFN-γ-producing T lymphocytes and IFN-γ in the lung may cause chronic airway lymphocytic inflammation and chronic cough hypersensitivity.

T helper 2 cells in asthma

Allergic asthma is among the most common immune-mediated diseases across the world, and type 2 immune responses are thought to be central to pathogenesis. The importance of T helper 2 (Th2) cells as central regulators of type 2 responses in asthma has, however, become less clear with the discovery of other potent innate sources of type 2 cytokines and innate mediators of inflammation such as the alarmins. This review provides an update of our current understanding of Th2 cells in human asthma, highlighting their many guises and functions in asthma, both pathogenic and regulatory, and how these are influenced by the tissue location and disease stage and severity. It also explores how biologics targeting type 2 immune pathways are impacting asthma, and how these have the potential to reveal hitherto underappreciated roles for Th2 cell in lung inflammation.

Interleukin-10-alveolar macrophage cell membrane-coated nanoparticles alleviate airway inflammation and regulate Th17/regulatory T cell balance in a mouse model

Background

Allergic airway disease (AAD) is a chronic disease characterized by airway inflammation, bronchoconstriction, and hyperresponsiveness. Although exogenous interleukin-10 (IL-10) alleviates allergic inflammation, it has a short half-life in vivo. Cell membrane-coated nanomaterials have been shown to protect therapeutic payloads and increase therapeutic efficacy.

Objective

This study was aimed at investigating the efficacy of a novel macrophage-based nanoparticle drug for the treatment of house dust mite (HDM)-induced allergic airway diseases.

Methods

IL-10-poly (lactic-co-glycolic acid (PLGA) nanoparticles were encapsulated in alveolar macrophage cell membranes. An allergic airway disease mouse model was established by repeated inhalation of HDM extracts. The mice were treated with free IL-10, IL-10-PLGA nanoparticles (IL10-NP), or IL-10-alveolar macrophage cell membrane-coated nanoparticles (IL10-AMNP). The therapeutic effects were evaluated by measuring airway hyperresponsiveness, lung inflammation, cytokine levels, and regulatory T cells (Treg)- T-helper 17 (Th17) cell balance.

Results

Compared to free IL-10, IL10-AMNP significantly reduced airway hyperresponsiveness and T-helper 2 (Th2)/Th17 cytokines and inhibited neutrophilia and eosinophilia recruitment into the airways of HDM-induced mouse models. Additionally, the balance between Tregs and Th17 cells was significantly improved in groups treated with IL10-AMNP.

Conclusion

This study demonstrated that PLGA nanoparticle cores coated with alveolar macrophage cell membranes can effectively deliver therapeutic cytokines to the lungs and improve the homeostatic balance between Tregs and Th17 cells. These findings suggest that macrophage-based nanoparticle drugs represent a promising approach for treating allergic airway diseases.

Severe Asthmatic Responses: The Impact of TSLP

Asthma is a chronic inflammatory disease that affects the lower respiratory system and includes several categories of patients with varying features or phenotypes. Patients with severe asthma (SA) represent a group of asthmatics that are poorly responsive to medium-to-high doses of inhaled corticosteroids and additional controllers, thus leading in some cases to life-threatening disease exacerbations. To elaborate on SA heterogeneity, the concept of asthma endotypes has been developed, with the latter being characterized as T2-high or low, depending on the type of inflammation implicated in disease pathogenesis. As SA patients exhibit curtailed responses to standard-of-care treatment, biologic therapies are prescribed as adjunctive treatments. To date, several biologics that target specific downstream effector molecules involved in disease pathophysiology have displayed superior efficacy only in patients with T2-high, eosinophilic inflammation, suggesting that upstream mediators of the inflammatory cascade could constitute an attractive therapeutic approach for difficult-to-treat asthma. One such appealing therapeutic target is thymic stromal lymphopoietin (TSLP), an epithelial-derived cytokine with critical functions in allergic diseases, including asthma. Numerous studies in both humans and mice have provided major insights pertinent to the role of TSLP in the initiation and propagation of asthmatic responses. Undoubtedly, the magnitude of TSLP in asthma pathogenesis is highlighted by the fact that the FDA recently approved tezepelumab (Tezspire), a human monoclonal antibody that targets TSLP, for SA treatment. Nevertheless, further research focusing on the biology and mode of function of TSLP in SA will considerably advance disease management.

Human PD-1 agonist treatment alleviates neutrophilic asthma by reprogramming T cells

BACKGROUND

Neutrophilic asthma is associated with disease severity and corticosteroid insensitivity. Novel therapies are required to manage this life-threatening asthma phenotype. Programmed cell death protein-1 (PD-1) is a key homeostatic modulator of the immune response for T-cell effector functions.

OBJECTIVE

We sought to investigate the role of PD-1 in the regulation of acute neutrophilic inflammation in a murine model of airway hyperreactivity (AHR).

METHODS

House dust mite was used to induce and compare neutrophilic AHR in wild-type and PD-1 knockout mice. Then, the therapeutic potential of a human PD-1 agonist was tested in a humanized mouse model in which the PD-1 extracellular domain is entirely humanized. Single-cell RNA sequencing and flow cytometry were mainly used to investigate molecular and cellular mechanisms.

RESULTS

PD-1 was highly induced on pulmonary T cells in our inflammatory model. PD-1 deficiency was associated with an increased neutrophilic AHR and high recruitment of inflammatory cells to the lungs. Consistently, PD-1 agonist treatment dampened AHR, decreased neutrophil recruitment, and modulated cytokine production in a humanized PD-1 mouse model. Mechanistically, we demonstrated at the transcriptional and protein levels that the inhibitory effect of PD-1 agonist is associated with the reprogramming of pulmonary effector T cells that showed decreased number and activation.

CONCLUSIONS

PD-1 agonist treatment is efficient in dampening neutrophilic AHR and lung inflammation in a preclinical humanized mouse model.

Recombinant T-cell epitope conjugation: A new approach for Dermatophagoides hypoallergen design

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only clinical approach that can potentially cure some allergic diseases by inducing immunological tolerance. Dermatophagoides pteronyssinus is considered as the most important source of mite allergens worldwide, with high sensitization rates for the major allergens Der p 1, Der p 2 and Der p 23. The aim of this work is to generate a hypoallergenic hybrid molecule containing T-cell epitopes from these three major allergens.

METHODS

The hybrid protein termed Der p 2231 containing T-cell epitopes was purified by affinity chromatography. The human IgE reactivity was verified by comparing those with the parental allergens. The hybrid was also characterized immunologically through an in vivo mice model.

RESULTS

The hybrid rDer p 2231 stimulated in peripheral blood mononuclear cells (PBMCs) isolated from allergic patients with higher levels of IL- 2, IL-10, IL-15 and IFN-γ, as well as lower levels of IL-4, IL-5, IL-13, TNF-α and GM-CSF. The use of hybrid molecules as a therapeutic model in D. pteronyssinus allergic mice led to the reduction of IgE production and lower eosinophilic peroxidase activity in the airways. We found increased levels of IgG antibodies that blocked the IgE binding to the parental allergens in the serum of allergic patients. Furthermore, the stimulation of splenocytes from mice treated with rDer p 2231 induced higher levels of IL-10 and IFN-γ and decreased the secretion of IL-4 and IL-5, when compared with parental allergens and D. pteronyssinus extract.

CONCLUSIONS

rDer p 2231 has the potential to be used in AIT in patients co-sensitized with D. pteronyssinus major allergens, once it was able to reduce IgE production, inducing allergen-specific blocking antibodies, restoring and balancing Th1/Th2 immune responses, and inducing regulatory T-cells.

Effect of transduced mesenchymal stem cells with IL-10 gene on control of allergic asthma

Asthma is an important pulmonary disease associated with T helper lymphocyte (Th)2 dominant immune response, which can initiate allergic and inflammatory reactions. Interleukin (IL)-10 is the main immune suppressor cytokine, and mesenchymal stem cells (MSCs) have an immune-modulatory potential that can be transduced with the expression of the IL-10 gene to control pathophysiology of allergic asthma. Bone marrow's MSCs were isolated and transduced with the expression vector that contains the expressible IL-10 gene. Then, allergic asthma mouse model was produced and treated with manipulated MSCs. Methacholine challenge test; measurement of IL-4, IL-5, IL-8, IL-13, IL-25, and IL-33; and total and ovalbumin (OVA)-specific immunoglobulin (Ig)E levels were done. Hyperplasia of the goblet cell, secretion of mucus, and peribronchiolar and perivascular eosinophilic inflammation were evaluated in lung pathological sections. IL-25, IL-33, and total IgE levels; AHR; eosinophilic inflammation; hyperplasia of the goblet cell; and secretion of mucus could be controlled in M, MV, and MV-10 groups, and the control in the MV-10 group was strong compared to M and MV groups. MSCs have immune-modulatory capacity that can control allergic asthma pathophysiology, and this effect can be strengthened and reinforced by the expression of IL-10 gene.

Lactoferrin Ameliorates Ovalbumin-Induced Asthma in Mice through Reducing Dendritic-Cell-Derived Th2 Cell Responses

Asthma is a chronic respiratory disease with symptoms such as expiratory airflow narrowing and airway hyperresponsiveness (AHR). Millions of people suffer from asthma and are at risk of life-threatening conditions. Lactoferrin (LF) is a glycoprotein with multiple physiological functions, including antioxidant, anti-inflammatory, antimicrobial, and antitumoral activities. LF has been shown to function in immunoregulatory activities in ovalbumin (OVA)-induced delayed type hypersensitivity (DTH) in mice. Hence, the purpose of this study was to investigate the roles of LF in AHR and the functions of dendritic cells (DCs) and Th2-related responses in asthma. Twenty 8-week-old male BALB/c mice were divided into normal control (NC), ovalbumin (OVA)-sensitized, and OVA-sensitized with low dose of LF (100 mg/kg) or high dose of LF (300 mg/kg) treatment groups. The mice were challenged by intranasal instillation with 5% OVA on the 21st to 27th day after the start of the sensitization period. The AHR, cytokines in bronchoalveolar lavage fluid, and pulmonary histology of each mouse were measured. Serum OVA-specific IgE and IgG1 and OVA-specific splenocyte responses were further detected. The results showed that LF exhibited protective effects in ameliorating AHR, as well as lung inflammation and damage, in reducing the expression of Th2 cytokines and the secretion of allergen-specific antibodies, in influencing the functions of DCs, and in decreasing the level of Th2 immune responses in a BALB/c mouse model of OVA-induced allergic asthma. Importantly, we demonstrated that LF has practical application in reducing DC-induced Th2 cell responses in asthma. In conclusion, LF exhibits anti-inflammation and immunoregulation activities in OVA-induced allergic asthma. These results suggest that LF may act as a supplement to prevent asthma-induced lung injury and provide an additional agent for reducing asthma severity.

Pulmonary IFN-γ Causes Lymphocytic Inflammation and Cough Hypersensitivity by Increasing the Number of IFN-γ-Secreting T Lymphocytes

PURPOSE

Respiratory viral infection increases the number of lung-resident T lymphocytes, which enhance cough sensitivity by producing interferon-γ (IFN-γ). It is poorly understood why IFN-γ-secreting T lymphocytes persist for a long time when the respiratory viruses have been removed.

METHODS

Repeated pulmonary administration of IFN-γ and intraperitoneal injection with different inhibitors were used to study the effects of pulmonary IFN-γ in mice and guinea pigs.

RESULTS

IFN-γ administration caused the increasing of IFN-γ-secreting T lymphocytes in both lung and blood, followed by the elevated physiological level of IFN-γ in the lung, the airway inflammation and the airway epithelial damage. IFN-γ administration also enhanced the cough sensitivity of guinea pigs. IFN-γ activated the STAT1 and extracellular signal-regulated kinase (ERK) pathways in lung tissues, released IFN-γ-inducible protein 10 (IP-10), and resulted in F-actin accumulation in lung-resident lymphocytes. The CXC chemokine receptor 3 (CXCR3) inhibitor potently suppressed all the IFN-γ-induced inflammatory changes. The STAT1 inhibitor mitigated IFN-γ-secreting T lymphocytes infiltration by inhibiting T lymphocytes proliferation. F-actin accumulation and the ERK1/2 pathway contributed to pulmonary IFN-γ-induced augmentation of the airway inflammation and increasing of IFN-γ-secreting T lymphocytes in blood.

CONCLUSIONS

High physiological levels of IFN-γ in the lung may cause pulmonary lymphocytic inflammation and cough hypersensitivity by increasing the number of IFN-γ-secreting T lymphocytes through the IP-10 and CXCR3 pathways.

Identifying a novel serum microRNA biomarker panel for the diagnosis of childhood asthma

The pathological mechanism of childhood asthma is complex, and timely diagnosis is the key to effective prevention and control of childhood asthma. We collected 170 serum samples from 95 children with asthma and 75 healthy children. Serum miRNA biomarkers were analyzed by Illumina sequencing for childhood asthma. Differentially serum miRNAs were confirmed with quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. The Illumina sequencing data showed the differential expression of 111 serum miRNAs among asthmatic and healthy children. After confirmation of miRNAs expression through qRT-PCR, four of them (namely hsa-miR-106a-5p, hsa-miR-18a-5p, hsa-miR-144-3p, and hsa-miR-375) manifested significant differential expression between asthmatic children and healthy controls. The biomarkers classification tree model created with these four miRNAs using the Biomarker Patterns Software could effectively separate childhood asthma and healthy children, with a specificity of 88.3%, a sensitivity of 95.0%, and an area under the curve (AUC) value of 0.942. The regulatory networks containing miRNAs and their gene targets suggested that the four miRNAs might have gene targets implicated in inflammation, immunity, and transcriptional efficiency. Taken together, this four-serum-miRNA panel is a promising biomarker to diagnose childhood asthma noninvasively.

Vitamin D ameliorates asthma-induced lung injury by regulating HIF-1α/Notch1 signaling during autophagy

Herein, we aimed to determine the effect of vitamin D (Vit D) and underlying mechanisms on asthma-induced lung injury via regulation of HIF-1α/Notch1 (hypoxia-inducible factor 1 alpha/neurogenic locus notch homolog protein 1) signaling during autophagy. We established an asthma mouse model using respiratory syncytial virus (RSV) nasal drop combined with ovalbumin (OVA) atomization. Mice were treated with different Vit D concentrations. Pathological changes and cell apoptosis were examined using hematoxylin-eosin (HE) staining and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end-labeling) assay, respectively. Additionally, periodic acid-Schiff (PAS) and Masson's trichrome staining solutions were used to examine changes in lung tissue. Immunofluorescence determined LC 3B (microtubule-associated protein 1 light chain 3B) expression in lung tissues, whereas western blotting and immunohistochemistry were used to evaluate other proteins, including HIF-1α and Notch1. Compared with the normal group, the asthma model group exhibited pathological lung tissue deterioration, elevated fibrosis, increased apoptosis cell numbers, and upregulated autophagy. Vitamin D supplementation ameliorated pathological changes and fibrosis in the lung tissue. Furthermore, Vit D treatment significantly suppressed apoptotic cell numbers and autophagy while enhancing the HIF-1α/Notch1 pathway. Given the HIF-1α/Notch1 agonistic activity, Vit D treatment inhibited apoptosis cell numbers, which were increased following asthma-induced upregulation of autophagy. Vitamin D improved asthma-induced lung tissue injury by suppressing autophagy via regulation of HIF-1α/Notch1 signaling in vivo.

Dermatophagoides pteronyssinus allergen Der p 22: Cloning, expression, IgE-binding in asthmatic children, and immunogenicity

BACKGROUND

Dust mite extract contains multiple components that, while useful in clinical allergy diagnosis and treatment, can cause serious side effects. Defining components of dust mite extract is important their contributions to allergic disease. This study aimed to characterize a novel dust mite allergen, Der p 22.

METHODS

We amplified the cDNA encoding Der p 22 from total RNA of the mite Dermatophagoides pteronyssinus, and inserted it into an expression construct for transformation to competent cells. Purified recombinant (r) Der p 22 was tested for IgE-binding reactivity in sera obtained from children with allergic asthma by the Affiliated Wuxi Children's Hospital of Nanjing Medical University (Jiangsu, China). rDer p 22 also was used to challenge BALB/c mice to assess effects on T helper cells and cytokine levels and applied to cultured lung epithelial cells to evaluate apoptosis and cytokine secretion.

RESULTS

rDer p 22 bound to IgE in 93.75% of sera from pediatric allergic asthma patients. Mice challenged with rDer p 22 had altered Th1/Th2 ratios in spleen and lymph, and lower levels of cytokines IFN-γ but higher levels of IL-4 and IL-10 in alveolar lavage fluid compared with controls (p < .05). Cultured lung epithelial cells had greater apoptosis rates and exhibited higher levels of IL-6, IL-8, and GM-CSF when treated with rDer p 22 compared with control treatment (p < .05).

CONCLUSIONS

Recombinant Der p 22 exhibited high IgE-binding rates in allergic children, indicating the activity of the recombinant protein and suggesting this novel allergen may be appropriate for inclusion in an allergy diagnostic workup. This finding is supported by in vitro and mouse in vivo studies showing rDer p 22 induced strong allergenic reactivity and apoptosis.

TFEB signaling attenuates NLRP3-driven inflammatory responses in severe asthma

BACKGROUND

NLRP3-driven inflammatory responses by circulating and lung-resident monocytes are critical drivers of asthma pathogenesis. Autophagy restrains NLRP3-induced monocyte activation in asthma models. Yet, the effects of autophagy and its master regulator, transcription factor EB (TFEB), on monocyte responses in human asthma remain unexplored. Here, we investigated whether activation of autophagy and TFEB signaling suppress inflammatory monocyte responses in asthmatic individuals.

METHODS

Peripheral blood CD14⁺ monocytes from asthmatic patients (n = 83) and healthy controls (n = 46) were stimulated with LPS/ATP to induce NLRP3 activation with or without the autophagy inducer, rapamycin. ASC specks, caspase-1 activation, IL-1β and IL-18 levels, mitochondrial function, ROS release, and mTORC1 signaling were examined. Autophagy was evaluated by LC3 puncta formation, p62/SQSTM1 degradation and TFEB activation. In a severe asthma (SA) model, we investigated the role of NLRP3 signaling using Nlrp3^-/- mice and/or MCC950 administration, and the effects of TFEB activation using myeloid-specific TFEB-overexpressing mice or administration of the TFEB activator, trehalose.

RESULTS

We observed increased NLRP3 inflammasome activation, concomitant with impaired autophagy in circulating monocytes that correlated with asthma severity. SA patients also exhibited mitochondrial dysfunction and ROS accumulation. Autophagy failed to inhibit NLRP3-driven monocyte responses, due to defective TFEB activation and excessive mTORC1 signaling. NLRP3 blockade restrained inflammatory cytokine release and linked airway disease. TFEB activation restored impaired autophagy, attenuated NLRP3-driven pulmonary inflammation, and ameliorated SA phenotype.

CONCLUSIONS

Our studies uncover a crucial role for TFEB-mediated reprogramming of monocyte inflammatory responses, raising the prospect that this pathway can be therapeutically harnessed for the management of SA.

Exacerbation of allergic asthma by somatic antigen of Echinococcus granulosus in allergic airway inflammation in BALB/c mice

BACKGROUND

There is ample evidence demonstrating a reverse relationship between helminth infection and immune-mediated diseases. Accordingly, several studies have shown that Echinococcus granulosus infection and hydatid cyst compounds are able to suppress immune responses in allergic airway inflammation. Previous studies have documented the ability of hydatid cysts to suppress aberrant Th2 immune response in a mouse model of allergic asthma. However, there is a paucity of research on the effects of protoscoleces on allergic asthma. Thus, this study was designed to evaluate the effects of somatic antigens of protoscoleces in a murine model of allergic airway inflammation.

METHODS

Ovalbumin (OVA)/aluminum hydroxide (alum) was injected intraperitoneally to sensitize BALB/c mice over a period of 0 to 7 days, followed by challenge with 1% OVA. The treatment group received somatic antigens of protoscoleces emulsified with PBS on these days in each sensitization before being challenged with 1% OVA on days 14, 15, and 16. The effects of somatic antigens of protoscoleces on allergic airway inflammation were evaluated by examining histopathological changes, the recruitment of inflammatory cells in the bronchoalveolar lavage, cytokine production in the homogenized lung tissue (IL-4, IL-5, IL-10, IL-17, and IFN-γ), and total antioxidant capacity in serum.

RESULTS

Overall, administration of somatic antigens of protoscoleces exacerbated allergic airway inflammation via increased Th2 cytokine levels in the lung homogenate, recruitment of eosinophils into bronchoalveolar lavage fluid, and pathological changes. In addition, total antioxidant capacity and IFN-γ levels declined following the administration of somatic antigens.

CONCLUSIONS

The results revealed that the co-administration of somatic products of protoscoleces with OVA/alum contributed to the exacerbation of allergic airway inflammation in BALB/c mice. Currently, the main cause of allergic-type inflammation exacerbation is unknown, and further research is needed to understand the mechanism of these interactions.

Systemic and local cytokine profile and risk factors for persistent allergic airway inflammation in patients sensitised to house dust mite allergens

Objective

To evaluate cytokine profile, vitamin D status, symptom score and quality of life in patients with persistent allergic airway diseases sensitised to house dust mites (HDM) in comparison with healthy individuals.

Material and methods

Patients sensitized to HDM with persistent AR and having symptoms for at least 2 years with or without AA were involved into the study. Measurements of vitamin D level in serum and IL-10, IL-13, IL-17, IL-22, IL-33 and IFN-gamma in serum and nasal lavage were performed by ELISA.

Results

Eighty-one subjects were involved into the study. Serum IL-10 concentration was higher in patients with AR than in patients with AR and AA (6.71 ± 1.73 vs. 1.98 ± 0.24, p < 0.05). IFN-gamma level in nasal lavage was higher in patients with AR and AA than in patients with AR (p < 0.01) and healthy individuals (p < 0.05) (7.50 ± 0.37 vs. 6.80 ± 0.99 vs. 6.50 ± 0.22). Serum IL-22 negatively correlated with IL-22 in nasal lavage, whereas serum IFN-gamma positively correlated with IFN-gamma in nasal lavage. Positive correlation between serum IL-17 and total IgE and negative correlation between IL-17 in nasal lavage and eosinophils in nasal smear were found in patients with AR and AA. Serum IFN-gamma decreased the risk of AR for healthy individuals. Serum IL-10 and vitamin D decreased risk for development of AA for patients with AR. IL-22 in serum and IL-10 and IL-33 in nasal lavage increased this risk.

Conclusion

Novel cytokines such as IL-22, IL-17 and IL-33 and vitamin D may be involved in pathogenesis of persistent airway inflammation in patients sensitized to HDM.

Regulated on Activation, Normal T cell Expressed and Secreted (RANTES) drives the resolution of allergic asthma

RANTES is implicated in allergic asthma and in T cell-dependent clearance of infection. RANTES receptor family comprises CCR1, CCR3, and CCR5, which are G-protein-coupled receptors consisting of seven transmembrane helices. Infections with respiratory viruses like Rhinovirus cause induction of RANTES production by epithelial cells. Here, we studied the role of RANTES in the peripheral blood mononuclear cells in cohorts of children with and without asthma and validated and extended this study to the airways of adults with and without asthma. We further translated these studies to a murine model of asthma induced by house dust mite allergen in wild-type RANTES and CCR5-deficient mice. Here we show an unpredicted therapeutic role of RANTES in the resolution of allergen-induced asthma by orchestrating the transition of effector GATA-3+CD4+ T cells into immune-regulatory-type T cells and inflammatory eosinophils into resident eosinophils as well as increased IL-10 production in the lung.

Advances in asthma: New understandings of asthma's natural history, risk factors, underlying mechanisms, and clinical management

The last 2 years yielded a proliferation of high-quality asthma research. These include new understandings of the incidence and natural history of asthma, findings on the effects of exposure to air pollution, allergens, and intake of acetaminophen, soy isoflavones, and polyunsaturated fatty acids, and exposure to microbial products. The past 2 years have benefited from great strides in determining potential mechanisms of asthma development and asthma exacerbations. These novel understandings led to identification and development of exciting new avenues for potential therapeutic intervention. Finally, there has been significant progress made in the development of tools to facilitate the diagnosis of asthma and measurement of airway physiology and in precision diagnostic approaches. Asthma guidelines were updated and new insights into the pharmacologic management of patients, including biologics, were reported. We review the most notable advances in the natural history of asthma, risk factors for the development of asthma, underlying mechanisms, diagnostic approaches, and treatments. Although greater knowledge of the mechanisms underlying responses and nonresponses to novel therapeutics and across asthma phenotypes would be beneficial, the progress over just the past 2 years has been immense and impactful.

Different Phenotypes in Asthma: Clinical Findings and Experimental Animal Models

Asthma is a respiratory allergic disease presenting a high prevalence worldwide, and it is responsible for several complications throughout life, including death. Fortunately, asthma is no longer recognized as a unique manifestation but as a very heterogenic manifestation. Its phenotypes and endotypes are known, respectively, as pathologic and molecular features that might not be directly associated with each other. The increasing number of studies covering this issue has brought significant insights and knowledge that are constantly expanding. In this review, we intended to summarize this new information obtained from clinical studies, which not only allowed for the creation of patient clusters by means of personalized medicine and a deeper molecular evaluation, but also created a connection with data obtained from experimental models, especially murine models. We gathered information regarding sensitization and trigger and emphasizing the most relevant phenotypes and endotypes, such as Th2-^high asthma and Th2-^low asthma, which included smoking and obesity-related asthma and mixed and paucigranulocytic asthma, not only in physiopathology and the clinic but also in how these phenotypes can be determined with relative similarity using murine models. We also further investigated how clinical studies have been treating patients using newly developed drugs focusing on specific biomarkers that are more relevant according to the patient's clinical manifestation of the disease.

Inflammation in Asthma Pathogenesis: Role of T cells, Macrophages, Epithelial Cells and Type 2 Inflammation

Asthma is a chronic disease with abnormal inflammatory and immunological responses. The disease initiated by antigens in subjects with genetic susceptibility. However, environmental factors play a role in the initiation and exacerbation of asthma attack. Asthma is T helper 2 (Th2)-cell-mediated disease. Recent studies indicated that asthma is not a single disease entity, but it is with multiple phenotypes and endotypes. The pathophysiological changes in asthma included a series of subsequent continuous vicious circle of cellular activation contributed to induction of chemokines and cytokines that potentiate inflammation. The heterogeneity of asthma influenced the treatment response. The asthma pathogenesis driven by varied set of cells such as eosinophils, basophils, neutrophils, mast cells, macrophages, epithelial cells and T cells. In this review the role of T cells, macrophage, and epithelial cells are discussed.

The magnitude of airway remodeling is not altered by distinct allergic inflammatory responses in BALB/c versus C57BL/6 mice but matrix composition differs

Allergic airway inflammation is heterogeneous with variability in immune phenotypes observed across asthmatic patients. Inflammation has been thought to directly contribute to airway remodeling in asthma, but clinical data suggest that neutralizing type 2 cytokines does not necessarily alter disease pathogenesis. Here, we utilized C57BL/6 and BALB/c mice to investigate the development of allergic airway inflammation and remodeling. Exposure to an allergen cocktail for up to 8 weeks led to type 2 and type 17 inflammation, characterized by airway eosinophilia and neutrophilia and increased expression of chitinase-like proteins in both C57BL/6 and BALB/c mice. However, BALB/c mice developed much greater inflammatory responses than C57BL/6 mice, effects possibly explained by a failure to induce pathways that regulate and maintain T-cell activation in C57BL/6 mice, as shown by whole lung RNA transcript analysis. Allergen administration resulted in a similar degree of airway remodeling between mouse strains but with differences in collagen subtype composition. Increased collagen III was observed around the airways of C57BL/6 but not BALB/c mice while allergen-induced loss of basement membrane collagen IV was only observed in BALB/c mice. This study highlights a model of type 2/type 17 airway inflammation in mice whereby development of airway remodeling can occur in both BALB/c and C57BL/6 mice despite differences in immune response dynamics between strains. Importantly, compositional changes in the extracellular matrix between genetic strains of mice may help us better understand the relationships between lung function, remodeling and airway inflammation.

Airway macrophage-intrinsic TGF-β1 regulates pulmonary immunity during early-life allergen exposure

BACKGROUND

Early life represents a major risk window for asthma development. However, the mechanisms controlling the threshold for establishment of allergic airway inflammation in early life are incompletely understood. Airway macrophages (AMs) regulate pulmonary allergic responses and undergo TGF-β-dependent postnatal development, but the role of AM maturation factors such as TGF-β in controlling the threshold for pathogenic immune responses to inhaled allergens remains unclear.

OBJECTIVE

Our aim was to test the hypothesis that AM-derived TGF-β1 regulates pathogenic immunity to inhaled allergen in early life.

METHODS

Conditional knockout (Tgfb1ΔCD11c) mice, with TGF-β1 deficiency in AMs and other CD11c+ cells, were analyzed throughout early life and following neonatal house dust mite (HDM) inhalation. The roles of specific chemokine receptors were determined by using in vivo blocking antibodies.

RESULTS

AM-intrinsic TGF-β1 was redundant for initial population of the neonatal lung with AMs, but AMs from Tgfb1ΔCD11c mice failed to adopt a mature homeostatic AM phenotype in the first weeks of life. Evidence of constitutive TGF-β1 signaling was also observed in pediatric human AMs. TGF-β1-deficient AMs expressed enhanced levels of monocyte-attractant chemokines, and accordingly, Tgfb1ΔCD11c mice exposed to HDM throughout early life accumulated CCR2-dependent inflammatory CD11c+ mononuclear phagocytes into the airway niche that expressed the proallergic chemokine CCL8. Tgfb1ΔCD11c mice displayed augmented TH2, group 2 innate lymphoid cell, and airway remodeling responses to HDM, which were ameliorated by blockade of the CCL8 receptor CCR8.

CONCLUSION

Our results highlight a causal relationship between AM maturity, chemokines, and pathogenic immunity to environmental stimuli in early life and identify TGF-β1 as a key regulator of this.

Experimental Mouse Models of Asthma and Analysis of CD4 T Cells

Asthma is a highly prevalent lung disease, characterized by airway dysfunction and chronic inflammation. Asthma occurs in both children and adults, but frequently originates in early life. Heterogeneous asthma phenotypes exist, but Th2 cells are key players in a large proportion of cases, while other CD4+ T cell subsets are also implicated in driving and limiting pathology. In this chapter, we describe methods for establishing allergic airway disease to model asthma in adult and neonatal mice, along with protocols for measuring key disease parameters and quantifying and phenotyping CD4+ T cell subtypes.

IL-2-Agonist-Induced IFN-γ Exacerbates Systemic Anaphylaxis in Food Allergen-Sensitized Mice

Food allergies are common, costly and potentially life-threatening disorders. They are driven by Th2, but inhibited by Th1 reactions. There is also evidence indicating that IL-2 agonist treatment inhibits allergic sensitization through expansion of regulatory T cells. Here, we tested the impact of an IL-2 agonist in a novel model for food allergy to hen´s egg in mice sensitized without artificial adjuvants. Prophylactic IL-2 agonist treatment expanded Treg populations and inhibited allergen-specific sensitization. However, IL-2 agonist treatment of already sensitized mice increased mast cell responses and allergic anaphylaxis upon allergen re-challenge. These effects depended on allergen-specific IgE and were mediated through IFN-γ, as shown by IgE transfer and blockade of IFN-γ with monoclonal antibodies. These results suggest that although shifting the allergic reaction toward a Treg/Th1 response inhibits allergic sensitization, the prototypic Th1 cytokine IFN-γ promotes mast cell activation and allergen-induced anaphylaxis in individuals that are already IgE-sensitized. Hence, while a Th1 response can prevent the development of food allergy, IFN-γ has the ability to exacerbate already established food allergy.

DEK-targeting aptamer DTA-64 attenuates bronchial EMT-mediated airway remodelling by suppressing TGF-β1/Smad, MAPK and PI3K signalling pathway in asthma

This study is to investigate the inhibitory effects and mechanisms of DEK-targeting aptamer (DTA-64) on epithelial mesenchymaltransition (EMT)-mediated airway remodelling in mice and human bronchial epithelial cell line BEAS-2B. In the ovalbumin (OVA)-induced asthmatic mice, DTA-64 significantly reduced the infiltration of eosinophils and neutrophils in lung tissue, attenuated the airway resistance and the proliferation of goblet cells. In addition, DTA-64 reduced collagen deposition, transforming growth factor 1 (TGF-β1) level in BALF and IgE levels in serum, balanced Th1/Th2/Th17 ratio, and decreased mesenchymal proteins (vimentin and α-SMA), as well as weekend matrix metalloproteinases (MMP-2 and MMP-9) and NF-κB p65 activity. In the in vitro experiments, we used TGF-β1 to induce EMT in the human epithelial cell line BEAS-2B. DEK overexpression (ovDEK) or silencing (shDEK) up-regulated or down-regulated TGF-β1 expression, respectively, on the contrary, TGF-β1 exposure had no effect on DEK expression. Furthermore, ovDEK and TGF-β1 synergistically promoted EMT, whereas shDEK significantly reduced mesenchymal markers and increased epithelial markers, thus inhibiting EMT. Additionally, shDEK inhibited key proteins in TGF-β1-mediated signalling pathways, including Smad2/3, Smad4, p38 MAPK, ERK1/2, JNK and PI3K/AKT/mTOR. In conclusion, the effects of DTA-64 against EMT of asthmatic mice and BEAS-2B might partially be achieved through suppressing TGF-β1/Smad, MAPK and PI3K signalling pathways. DTA-64 may be a new therapeutic option for the management of airway remodelling in asthma patients.

The anti-asthmatic potential of flavonol kaempferol in an experimental model of allergic airway inflammation

Flavonol kaempferol possesses a broad spectrum of potent pharmacological activities that seem to be effective in the modulation of allergic respiratory diseases. In our study, an experimental animal model of ovalbumin (OVA)-induced allergic airway inflammation in guinea pigs was used to determine the anti-asthmatic potential of kaempferol. The parameters of specific airway resistance (sRaw) and cough reflex response were evaluated in vivo. In vitro, an assessment of tracheal smooth muscle (TSM) contractility and analyses of inflammatory cytokines (IL-4, IL-5, IL-13, GM-CSF, IFN-γ), transforming growth factor (TGF-β1), immune cells count and ciliary beating frequency (CBF) were performed. Both single (6, 20 mg/kg b. w. p. o.) and long-term administered doses of kaempferol (20 mg/kg b. w. p. o., 21 days) suppressed sRaw provoked by histamine in conscious animals. The administration of kaempferol for 21 days attenuated histamine-induced TSM contractility in vitro and ameliorated the progression of chronic airway inflammation by decreasing the levels of IL-5, IL-13, GM-CSF, eosinophil count in bronchoalveolar lavage (BAL) fluid and TGF-β1 protein level in lung tissue. Kaempferol also eliminated the alterations in cough reflex sensitivity invoked by OVA-sensitization, but it did not affect CBF. The results demonstrate that flavonol kaempferol can modulate allergic airway inflammation and associated asthma features (AHR, aberrant stimulation of cough reflex).

The Role of T Cells and Macrophages in Asthma Pathogenesis: A New Perspective on Mutual Crosstalk

Asthma is associated with innate and adaptive immunity mediated by immune cells. T cell or macrophage dysfunction plays a particularly significant role in asthma pathogenesis. Furthermore, crosstalk between them continuously transmits proinflammatory or anti-inflammatory signals, causing the immune cell activation or repression in the immune response. Consequently, the imbalanced immune microenvironment is the major cause of the exacerbation of asthma. Here, we discuss the role of T cells, macrophages, and their interactions in asthma pathogenesis.

Transcriptomic analysis reveals diverse gene expression changes in airway macrophages during experimental allergic airway disease

Background: Airway macrophages (AMs) are the most abundant leukocytes in the healthy airway lumen and have a highly specialised but plastic phenotype that is governed by signals in the local microenvironment. AMs are thought to maintain immunological homeostasis in the steady state, but have also been implicated in the pathogenesis of allergic airway disease (AAD). In this study, we aimed to better understand these potentially contrasting AM functions using transcriptomic analysis. Methods: Bulk RNA sequencing was performed on AMs (CD11c + Siglec F + CD64 + CD45 + SSC hi) flow cytometry sorted from C57BL/6 mice during experimental AAD driven by repeated house dust mite inhalation (AMs HDM), compared to control AMs from non-allergic mice. Differentially expressed genes were further analysed by hierarchical clustering and biological pathway analysis. Results: AMs HDM showed increased expression of genes associated with antigen presentation, inflammatory cell recruitment and tissue repair, including several chemokine and matrix metalloproteinase genes. This was accompanied by increased expression of mitochondrial electron transport chain subunit genes and the retinoic acid biosynthetic enzyme gene Raldh2. Conversely, AMs HDM displayed decreased expression of a number of cell cycle genes, genes related to cytoskeletal functions and a subset of genes implicated in antimicrobial innate immunity, such as Tlr5, Il18 and Tnf. Differential gene expression in AMs HDM was consistent with upstream effects of the cytokines IL-4 and IFN-γ, both of which were present at increased concentrations in lung tissue after HDM treatment. Conclusions: These data highlight diverse gene expression changes in the total AM population in a clinically relevant mouse model of AAD, collectively suggestive of contributions to inflammation and tissue repair/remodelling, but with decreases in certain steady state cellular and immunological functions.

Transcriptomic analysis reveals diverse gene expression changes in airway macrophages during experimental allergic airway disease

Background: Airway macrophages (AMs) are the most abundant leukocytes in the healthy airway lumen and have a highly specialised but plastic phenotype that is governed by signals in the local microenvironment. AMs are thought to maintain immunological homeostasis in the steady state, but have also been implicated in the pathogenesis of allergic airway disease (AAD). In this study, we aimed to better understand these potentially contrasting AM functions using transcriptomic analysis. Methods: Bulk RNA sequencing was performed on AMs flow cytometry sorted from C57BL/6 mice during experimental AAD driven by repeated house dust mite inhalation (AMs HDM), compared to control AMs from non-allergic mice. Differentially expressed genes were further analysed by hierarchical clustering and biological pathway analysis. Results: AMs HDM showed increased expression of genes associated with antigen presentation, inflammatory cell recruitment and tissue repair, including several chemokine and matrix metalloproteinase genes. This was accompanied by increased expression of mitochondrial electron transport chain subunit genes and the retinoic acid biosynthetic enzyme gene Raldh2. Conversely, AMs HDM displayed decreased expression of a number of cell cycle genes, genes related to cytoskeletal functions and a subset of genes implicated in antimicrobial innate immunity, such as Tlr5, Il18 and Tnf. Differential gene expression in AMs HDM was consistent with upstream effects of the cytokines IL-4 and IFN-γ, both of which were present at increased concentrations in lung tissue after HDM treatment. Conclusions: These data highlight diverse gene expression changes in the total AM population in a clinically relevant mouse model of AAD, collectively suggestive of contributions to inflammation and tissue repair/remodelling, but with decreases in certain steady state cellular and immunological functions.

Resolution of allergic asthma

Allergic asthma is an inflammatory disease of the airways characterized by recurrent episodes of wheezing and bronchoconstriction. Chronic inflammation may finally lead to structural damage followed by airway remodeling. Various studies in recent years contributed to unravel important aspects of the immunopathogenesis of asthma and adapted new pharmaceutical developments. Here, I consider some novel insights into the immunopathogenesis of asthma and the protective and pathogenic roles of some innate and adaptive immune cells as well as the function of soluble mediators such as cytokines. Particular attention will be given to new concepts on resolution of chronic airway inflammation for prevention of airway structural damage.